ZSE Aviation Forecast Discussions

000 FXUS66 KSEW 292129 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 229 PM PDT Thu Oct 29 2020 .SYNOPSIS...A front will bring a shot of rain and breezy winds late tonight with showers tapering on Friday. Dry weather will return this weekend with an upper ridge again building. A shift to a wetter pattern is expected next week as a series of fronts move across the region. && .SHORT TERM /TONIGHT THROUGH SUNDAY/...An upper ridge shifts east of the region this afternoon as a frontal system approaches the region from the northwest. Rain looks to reach much of the coast by midnight then spread into the interior during the early hours of Friday morning. Westerly flow aloft will shadow much of the Puget Sound on Friday, but a decent westerly post-frontal punch through the Strait of Juan de Fuca will get a convergence zone going later Friday morning. Upper ridging begins to rebuild into the region by Friday evening for drying conditions. Saturday is likely to start on the cloudy side for much of the lowlands, but upper ridging will continue to build into the region and most areas should clear out by mid afternoon. Temperatures on Saturday will be right around seasonal normals. The upper ridge axis shifts onshore on Sunday. A strengthening surface ridge east of the Cascades will turn the flow offshore. With the exception of some patchy night and morning fog, Sunday looks clear with high temperatures edging upward to slightly above normal. .LONG TERM /MONDAY THROUGH THURSDAY/...But like all good things, it`s all about to end. And in sharp contrast to the first week of November last year, model ensembles are in good agreement that wetter and unsettled conditions will arrive next week. Upper ridging shifts east of the area by Monday afternoon as a frontal system spreads more rain into the region Monday night and Tuesday. It is likely to be followed by a secondary, stronger system Tuesday night or Wednesday. And, yes, a third system less than 24 hours later. If the Tuesday and Wednesday systems verify as depicted in a number of models at this time, hydrologically significant precipitation may result (see hydrology discussion). After October`s run of below average precipitation and warmer than average temperatures, the fortunes appear to be turning. 27 && .AVIATION...Westerly flow aloft is expected to last through Friday as a low pressure system moves through the area tonight and into tomorrow. Southerly surface winds are expected to start picking up after 0600 UTC. The front is expected to have passed through the Western Washington area by 1200 UTC. Winds behind this front will be westerly at 10-15 knots with gusts up to 20-25 knots for most locations. Winds at KBLI and KCLM should expect winds to be closer to 15-20 knots with gusts 25-30 knots. Winds should decrease and become west/northwesterly after 0000 UTC Saturday. With the incoming system clouds will continue to move into the area throughout tonight. MVFR to IFR conditions are expected for most locations, with ceilings around 1000-2000 feet and light rain dropping visibility slightly. KCLM and KBLI are the exceptions to this where ceilings will be closer to 2000-3000 feet. Sky cover is expected to improve Friday night. KSEA...There is some slight clearing over the Puget Sound region this afternoon. This clearing may reach the terminals for a few hours this afternoon bringing conditions up to VFR. Clouds will come back in this evening resulting in MVFR conditions. Ceilings around 1500-2000 feet with west winds 15-20 knots and gusts up to 25 are expected tonight and into Friday afternoon. Butwin && .MARINE...The rest of the afternoon is expected to be fairly quiet over the waters of Western Washington, however this is expected to change during the overnight hours. A front associated with an area of low pressure to our north is expected to pass through the area tonight into tomorrow morning. Southerly winds are expected to be increasing around midnight tonight. As the front moves through winds will shift to become more westerly but will remain elevated. Expect sustained winds in the coastal and inner waters to be at 20-30 knots through tomorrow afternoon. Winds in the central and east entrance of the Strait of Juan de Fuca are expected to be gale strength starting early Friday morning and lasting to the afternoon before gradually decreasing Friday night. Winds are not the only concern for the coastal waters. The swell is expected to be 10-15 feet with a period around 10 seconds as the system moves through. Once the front passes things will improve slightly, with swell closer to 10 feet and a period of 10 seconds throughout the coastal waters by Friday night. The weekend is expected to be rather quiet. The next system that will bring elevated seas is not expected until Tuesday. Butwin && .HYDROLOGY...No river flooding is expected through Monday. A series of stronger frontal system will begin to impact the region beginning Monday night and Tuesday through much of next week. A number of models depict potentially hydrologically significant precipitation over the Olympics and the North Cascades. If this trend continues, rivers running off those ranges could experience sharp rises and potential flooding. Stay tuned. 27 && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...Small Craft Advisory from 2 AM Friday to 6 AM PDT Saturday for Coastal Waters From Cape Flattery To James Island 10 To 60 Nm-Coastal Waters From Cape Flattery To James Island Out 10 Nm-Coastal Waters From James Island To Point Grenville 10 To 60 Nm-Coastal Waters From James Island To Point Grenville Out 10 Nm-Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm-Coastal Waters From Point Grenville To Cape Shoalwater Out 10 Nm-West Entrance U.S. Waters Strait Of Juan De Fuca. Gale Warning from 6 AM to 6 PM PDT Friday for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca. Small Craft Advisory from 2 AM to 6 PM PDT Friday for Northern Inland Waters Including The San Juan Islands. Small Craft Advisory from 2 AM Friday to 2 AM PDT Saturday for Admiralty Inlet. Small Craft Advisory from 2 AM to 2 PM PDT Friday for Puget Sound and Hood Canal. && $$ www.weather.gov/seattle

743 FXUS66 KPQR 292153 AFDPQR Area Forecast Discussion National Weather Service Portland OR 253 PM PDT Thu Oct 29 2020 .SYNOPSIS...A weakening front will bring clouds and areas of light rain to the region on Friday, mainly through mid-day. Then, back to dry weather, though will see areas of late night/morning fog again this weekend. Rather zonal flow into the Pac NW next week, with a series of fronts expected. This will bring lot more in way of clouds, and rain at times next week. && .SHORT TERM...Tonight through Sunday...Clouds clearing out in the valley but quite stubborn south of Salem. Do think the south valley will clear but will take a while. Satellite shows a front now near 135W off the WA/OR coast continue to progress eastward. This front to move to the coast late tonight then across the interior during the morning hours. But before that will likely have enough clearing before frontal clouds arrive for some fog to redevelop in the interior valleys. Front is not all that strong will modest lift as the forecast area is more in the tail end of the front. The bulk of the moisture is below 850 mb so the coastal mountains will cut into rain amounts reaching the valley. Looks like the southwest WA zones will have the higher rain amounts. High pressure builds back into the region later Friday and Friday night. So, will see clearing skies Friday night, with areas of fog again. Overall, mild again on Saturday, under variable high clouds. Could see bit of north to northeast flow aloft, which give bit more support for mild temperatures on Saturday. /mh .LONG TERM...Sunday night through Wednesday...As we switch from October to November, almost like clockwork we transition into a progressive pattern. High pressure at the surface and aloft will hold through at least Monday morning. During this time will likely see valley temperatures inversions for at least some fog or low clouds in the morning with afternoon sunshine and temperatures climbing to the upper 50s to low 60s. But by Monday morning the ridge has shifted east of the Cascades. This will open the door to a series of fronts moving through during the week. The first front arrives later Monday into Tuesday but is in a weakening state by the time it arrives. This may be delayed or weakend further as cluster analysis has some of the groups weakening the ridge less. Stronger fronts arrives for the latter half of the week as a much zonal jet noses into western WA beginning Wed. 12Z ECMWF & GFS currently indicating the jet peaking 150-160 kt Wed evening. The forecast area will be in the warmer side of the jet so snowlevel will be above Cascade peaks. /mh && .AVIATION...Areas of LIFR/IFR conditions continue to linger within the central and southern Willamette Valley. Satellite observations are showing these lingering cigs slowly eroding. KSLE and KTTD should improve to VFR within the next hour or two. However, KEUG will likely be locked into LIFR for the remainder of the day. Otherwise, VFR will persist through 06Z to 08Z Friday when MVFR/IFR conditions are likely to return along with precipitation across the area. Southerly winds likely to gust up to 25 kt along the coast starting around 11Z Friday. For detailed regional Pac NW weather information, go online to: http://weather.gov/zse KPDX AND APPROACHES...VFR under clear skies will persist through around 07Z Friday, when MVFR conditions are likely to return along with precipitation. /42 && .MARINE...Northerly winds will continue across the waters through Thursday night, with the strongest winds expected south of Cascade Head. Seas will stay between 4 to 6 ft through Thursday. Low pressure will move into the Queen Charlotte Sound late Thursday night and swing a weakening front across the waters early Friday morning. Strongest winds look to stay confined to zones PZZ270 and PZZ250. Sustained winds between 15 to 20 kt with gusts up to 25 kt are likely. Also, seas will likely build to around 10 ft Friday afternoon and subside by Friday night for the same zones. High pressure will be reestablished over the weekend. Northerly winds and seas between 4 to 6 ft can be expected. - BPhillips/42 && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...Small Craft Advisory from 11 PM this evening to 11 PM PDT Friday for coastal waters from Cape Shoalwater WA to Cascade Head OR out 60 NM. && $$ Interact with us via social media: www.facebook.com/NWSPortland www.twitter.com/NWSPortland

000 FXUS66 KMFR 292151 AFDMFR Area Forecast Discussion National Weather Service Medford OR 251 PM PDT Thu Oct 29 2020 .DISCUSSION... Current satellite observations are showing a cloud-free southern Oregon and northern California. The Slater and Red Salmon fires are producing a little bit of smoke, mainly hovering around the fire locations. This is largely indicative of the influence of high pressure over our area. This area of high pressure will weaken tonight into tomorrow as a disturbance moves over it it, well to our north. This means that we`ll see a disruption to the east winds we`ve been experiencing--turning them to be from the west to southwest. The winds will also increase in speed. This will also push the marine layer a little farther inland on Friday, and it will bring a slight chance for very light precipitation (measurable drizzle) to the coast and areas around and north of Roseburg tomorrow night. Temperatures may also become a bit cooler during the day and warmer at night for areas west of the Cascades due to slightly increased cloud cover. Then, on Halloween, conditions will start reverting back to the influence of high pressure. The clouds will clear out by the afternoon, and although temperatures will be above normal for this time of year, they`ll be a few degrees cooler than what we`re expecting for this afternoon. Any outdoor activities should see mainly clear skies with no chances of rain. Temperatures will be mild to warm across the area. 60s across the Coast and Umpqua basin, 70s in the Rogue Valley and northern California, and 60s for areas east of the Cascades. These temperatures will begin decreasing pretty quickly after the sun sets due to those clear skies. The area of high pressure will strengthen once again bringing more east winds to the area Sunday through Tuesday, and keeping us drier and well warmer than normal. Then, by mid-week another front will weaken the ridge and bring some more light rain to the coast and areas north of the Douglas/Josephine and Jackson County Line, more clouds, and cooler weather. More importantly, this front will allow a stronger front to approach the area late next week. Ensembles are showing that this system will be considerably wetter, with many iterations showing at least a half an inch of rain in Medford. Have not quite jumped on board with that since we tend to get downsloped in these scenarios, but late next week into next weekend could see the first significant rainfall we`ve had since early October. Please keep an eye on the forecast, since this could shift our operations toward the winter/wet season. -Schaaf Sneaker waves...Latest model data suggests a long period west swell arriving at the coast late Sunday, and this could bring an enhanced risk for sneaker waves. We`ll continue to evaluate the data in future shifts to determine if a Beach Hazards Statement is needed. -Keene && .AVIATION...For the 29/18Z TAFS...VFR conditions will prevail through the TAF period over most locations. The exceptions are the coast/coastal valleys north of Cape Blanco and the Umpqua Basin near Roseburg. In those locations, IFR conditions will form first this evening at the coast and by early Friday morning in the Umpqua Basin and Roseburg. Conditions will likely improve to VFR late Friday morning. Keene && .MARINE...Updated 200 PM PDT Thursday 29 Oct 2020...Calmer conditions are expected through Friday. A weak front will move onshore late Friday and bring building northwest swell but conditions are expected to remain just below Small Craft Advisory criteria. The thermal trough will develop and set up along the coast again this weekend and there`s a chance it could bring low end Small Craft conditions in the southern waters, but confidence is not high enough to include a headline at this time. Later shifts will reevaluate this and should confidence increase, a headline may for Small Craft conditions may be added. -Keene && .FIRE WEATHER...Updated 200 PM PDT Thursday Oct 29 2020...High pressure will result in another night of poor RH recovery over the upper slopes and ridges tonight into Friday morning. The good news is that winds will be relatively light. A cold front will move into the area on Friday resulting in breezy west-northwest winds east of the Cascades and in NE California. An associated marine push will bring higher RH and lower temperatures, as well as another surge of moderate easterly winds in southwestern Oregon and northwestern California Friday night into Saturday. Upper ridging over the area is then likely to gradually give way to low pressure troughing over the Pacific Northwest next week with increasing probabilities of precipitation beginning on Election Day. -Spilde && .MFR WATCHES/WARNINGS/ADVISORIES... OR...None. CA...None. Pacific Coastal Waters...None. $$

000 FXUS66 KEKA 292200 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 300 PM PDT Thu Oct 29 2020 .SYNOPSIS...Dry weather is expected through early next week, with chilly mornings and warm afternoons. Skies will generally remain clear except for occasional coastal clouds and patches of fog. && .DISCUSSION...Upper level ridging will dominate through early next week. Above normal afternoon temperatures are expected in the interior each day. With low dewpoints, clear skies and light winds, temperatures will likely fall into the mid 30`s in some of the valleys of Humboldt county again tonight. A frost advisory has been issued for these colder valleys of Humboldt county. Many sites in Trinity and northern Mendocino counties have already seen a season ending freeze. Frost advisories and freeze warnings will no longer be issued for Trinity and northern Mendocino counties until Spring. A transient shortwave disturbance will move across the Pacific NW on Friday and temporarily flatten the ridge. This shortwave will likely induce a low level push of higher humidities for coastal areas and adjacent river valleys as high pressure rebuilds offshore behind the wave. Satellite imagery was already showing a southerly wind reversal south of Cape Mendo, with low clouds and fog propagating northward along the shoreline of Mendocino county this afternoon. The offshore pressure gradients will likely keep the shallow moist air and low clouds from pushing into the adjacent river valleys tonight. The fog and low cloud may push north of Cape Mendocino later tonight and early Friday morning. High resolutions model guidance has not been handling this southerly wind reversal and increase in coastal stratus well. Even BUFKIT time-height sections for coastal land sites were not showing a considerable increase in low level humidity and low clouds tonight and Friday. Just offshore, profiles moisten up tonight and Friday, suggesting a greater potential for low cloud cover along the entire coast on Friday. The low level moisture should push deeper into the coastal river valleys Friday night and Saturday, providing better RH recoveries except over the highest ridgetops. Otherwise, inland areas will remain quite dry through the weekend. A few upper level stations were still reporting 5 to 10% RH`s today. Even sites with higher RH`s, 15-25%, sites were still reaching red flag with gusts to 20 mph this afternoon. Locally critical fire weather conditions are expected for the windier ridges through Friday. Widespread and long duration red flag conditions are not expected, however. A marine push Friday night should result in higher RH`s this weekend, however the highest mountain peaks will probably not see any significant RH increase. The ridge aloft will spring back up quickly this weekend, for continued above normal daytime temperatures in the interior. Another transient shortwave will move into the ridge early next week, around Tuesday, and may provide the northern most portion of the forecast area with light rain amounts. The ECMWF and ENS were generally much wetter than the GFS/GEFS and CMCE even into Wednesday and Thursday. We could see more light rain on both these day across the northern portion of the area, however confidence remains low. Southern portions of the forecast area will most likely remain dry. && .AVIATION...Offshore flow and a dry airmass continue to bring clear and dry conditions across the area this morning. The satellite is showing widespread stratus off the Mendocino coast, but it doesn`t appear to be making it onshore. winds appear to remain northerly near Cape Mendocino. Hires models are showing stratus developing off the Humboldt and Del Norte coasts tonight, however confidence is low as to onshore intrusion or into the coastal airports. Winds will remain light through period and inland areas are expected to remain clear. /EYS && .MARINE...A weak nearshore flow reversal has developed today, with light southerlies near the coast and northerlies in the western outer waters. This reversal is expected to break down tomorrow as a surface high nears the PNW, moderately strengthening the local pressure gradient and generating building northerlies late Friday into Saturday. Northerlies may reach SCY levels in the usual spot downwind of Cape Mendocino Friday afternoon, however coverage currently looks pretty marginal. These are expected to hold overnight before spreading into to the western half of the Northern outers by Saturday morning. Winds then significantly weaken late this weekend, with light southerlies expected to develop north of Trinidad and light northerlies to the south of Fort Bragg. This wind pattern is expected to persist from early through mid next week. A subtle, brief spike of short period northerly seas will be generated Friday and Saturday from local winds, and these should diminish fairly quickly overnight Saturday. A mid period NNW pulse around 6 ft should fill in during the day on Saturday as well, however this is expected to be short-lived, quickly waning overnight on Saturday as well. A small, long period WNW swell from a storm currently off the Aleutians is expected to arrive Sunday afternoon. This may drive a low-end sneaker wave threat for late Sunday afternoon and Monday. /TDJ && .EKA WATCHES/WARNINGS/ADVISORIES... CA...NORTHWEST CALIFORNIA COASTAL WATERS...None. && $$ Visit us at https://www.weather.gov/eureka Follow us on Facebook and Twitter at: https://www.facebook.com/NWSEureka https://www.twitter.com/NWSEureka For forecast zone information see the forecast zone map online: https://www.weather.gov/images/eka/zonemap.png

000 FXUS66 KMTR 300004 AFDMTR Area Forecast Discussion National Weather Service San Francisco Bay Area 504 PM PDT Thu Oct 29 2020 .SYNOPSIS...High pressure will bring mostly sunny, mild afternoons and cool, mainly clear nights through the remainder of the week. A slight warming trend is then forecast over the upcoming weekend, along with continued dry weather conditions. && .DISCUSSION..as of 2:39PM PDT Thursday...Water Vapor Imagery captures a low pressure system centered to the north of Hawaii and another low quickly moving towards British Columbia this afternoon. Moisture is being channeled between the two systems and traveling up and around the 586dm 500 hPa ridge whose axis is just off the West Coast. With the exception of a few low-lying stratus, clear skies and relatively dry conditions are in place all across the CWA as a result. Elevated smoke is also present in the form of haze over the Central Coast and portions of the Bay Area this afternoon as smoke from the Creek Fire traverses the Central Valley. Visible Satellite imagery captures a narrow haze band exiting southern Monterey County shoreline and over our southern waters. Given the stable air mass overhead, expecting hazy conditions across portions of the CWA to continue through the rest of the day. Max temps in the 70s F near the coast and low 80s F in the interior valleys still on track. Given the time of year and the subsequent shorter days and longer nights, will continue to see sharp variations in diurnal max/min temperatures, especially across the interior valleys. For tonight, expecting overnight temps to dip down into the 40s F across much of the interior, with low 40s F (and some isolated pockets of upper 30s F) possible in valleys regionwide. As for the Bay Shoreline and the coast, min temps in the upper 40s F and low 50s F are expected. Could see some shallow stratus develop through the evening as well, but not expecting it to be as prevalent until Friday. The coast will see an increase in marine layer influence by Friday. As a result, expecting max temps on Friday along the Coast and Bay Shoreline to be 2-3 degrees F cooler. Interior locations, on the other hand, will see max temps 3 to 5 degrees F warmer than today as the upper-level ridge continues to come ashore. Subtle warming trend will continue through the weekend all across the CWA and can expect for max temps by Sunday for the interior to get into the 80s F while coastal areas will reach the 65-79 F range. GEFS and ECMWF ENS members suggest a very robust pattern next week. Following the passage of the upper-level ridge, the upper-level trough associated with the low pressure to the north of Hawaii will channel some of its moisture over to the trough due west of BC. ECMWF and GFS IVT values expected to increase substantially along the PAC NW as moisture plume comes ashore by midweek next week. Unfortunately, not looking like much, if any, of this moisture makes it down to Central California, so for now members are suggesting the first of two dry cold FROPAs for the CWA through Election Day. A lot of uncertainty over the chances for precipitation during the second half of next week, with most members still trending dry while a few continue to show the chance for it to develop. On our current runs of the ECMWF and GFS, see that IVT values do increase off the PAC NW coast and seem to travel in the direction of our CWA through Friday, but this comes with some major synoptic-scale caveats. Looking across the PAC, we find that an upper-level trough will begin to dig itself over the Sea of Japan during the first part of next week. Depending on how much it deepens, will have a large influence on the downstream development of an upper-level ridge over the north-central PAC. Should this ridge build enough, will see it cut off the moisture transport between the central PAC and West Coast by midweek. And should that transpire, will see a second dry cold FROPA over the CWA during the second-half of the week. As such, will continue to monitor the setup closely, but confidence remains low that precip will move over our CWA in the foreseeable future. && .AVIATION...as of 5:03 PM PDT Thursday...For 00z tafs. VFR across all terminals with clear skies. Stratus remains well offshore for most of the area`s coastline, except for some patchy clouds SW of Santa Cruz Co and from northern Sonoma Co coast northward. With dry airmass in place and no onshore gradient, expect terminals to remain mostly clear through evening, and possibly throughout the TAF period. Will monitor marine layer development for any coastal impacts overnight. Some lingering smoke from distant fires may bring minimal amounts of HZ/FU. Winds generally light with some breezier conditions through coastal valleys and around KSFO. Light to calm winds overnight. Vicinity of KSFO...VFR. Clear skies throughout the area. Winds have picked up within the last hour and are now WNW at 18 kt but should begin to dropoff as the evening progresses. Clear skies expected through evening, with possible few to sct late overnight. VFR expected Friday afternoon with return of onshore winds. SFO Bridge Approach...Similar to KSFO. Monterey Bay Terminals...VFR. Winds light along the bay but breezier NW winds in the Salinas Valley. Patch of stratus entering the bay but not expected to reach land. Clear skies over the terminals for the evening hours with chance of stratus developing early Friday morning. VFR expected Friday afternoon. && .MARINE...as of 03:13 PM PDT Thursday...Predominately light northerly winds through tonight. Winds increase gradually Friday and into Saturday. Mixed seas will persist through the period with a pair of northwest swell trains in addition to a lighter southerly swell. && .MTR WATCHES/WARNINGS/ADVISORIES... .Tngt...NONE. && $$ PUBLIC FORECAST: Diaz AVIATION: Lorber MARINE: BFG Visit us at www.weather.gov/sanfrancisco Follow us on Facebook, Twitter, and YouTube at: www.facebook.com/nwsbayarea www.twitter.com/nwsbayarea www.youtube.com/nwsbayarea

000 FXUS66 KOTX 292253 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 353 PM PDT Thu Oct 29 2020 .SYNOPSIS... A cold front will bring gusty winds and chance for showers Friday. High pressure will return for the weekend into early next week for more periods of sunshine and mild temperatures. Breezy and unsettled weather returns the middle to end of the week. Changes could arrive by next weekend with the potential for another unseasonably cold air mass. && .DISCUSSION... ...GUSTY WEST TO SOUTHWEST WINDS FRIDAY... Tonight through Friday night: A potent shortwave is approaching the Pac NW Coast tonight and will track through on Friday. Mostly clear conditions will in place this evening and first half of the night. Combined with light winds, thinking we could see patchy fog developing within the valleys of NE WA and N ID mainly Silver Valley northward. Light southeast winds will begin to develop in the L-C Valley and Palouse in response to a 990mb surface low crossing inland just north of Vancouver Island around midnight. The surface low will fill 4-5 mb while crossing through southern BC then looks to deepen or drop another 5 mb back closer to 990mb again while crossing the Northern Rockies into southern Alberta and Saskatchewan. This will drag a strong cold front across the Inland NW Friday morning bringing a band of clouds and chance for showers. Heaviest shower activity will be along the Cascade Crest and Idaho Panhandle but a few showers will be possible across the eastern reaches of WA. As a matter of fact, we have seen a slight uptick in the potential for a 0.01" for locations like Colville, Spokane, and Pullman but this is generally all the QPF we are expected for these areas. The lee of the Cascades will get shadowed with nothing more than sprinkles or just passing clouds. The combination of cold air advection and a 14-15mb cross-CWA pressure gradient on Friday will deliver gusty winds to a good portion of the Inland NW. Winds will come from the west and southwest with speeds of 10-25 mph and be accompanied by gusts of 30-40 mph. Strongest winds will blow from the East Slopes...across the Columbia Basin...and into the Central Idaho Panhandle. This includes the foothills of the Blue Mountains, Palouse, and West Plains. Models have been trending stronger with the frontal passage with each consecutive run and we are now seeing nearly a 100% chance for wind gusts of at least 34kts across a big portion of the Upper Columbia Basin along the Hwy 2 corridor. Guidance from the UW WRF also suggest isolated gusts of 40-45 mph possible along this corridor so would not rule out a few stronger gusts however there is some uncertainty. The uncertainty comes from looking into the NAM. The NAM also has these stronger winds speeds advertised in the vertical profiles but keeps the surface decoupled from these stronger winds initially and mixes up to these levels a few hours later. By the time the NAM mixes into these levels, peak wind speeds are closer to 35 mph. So overall, we are confident for wind gusts 30-40 mph but somewhat uncertain if we will hit peak gusts in excess of 40 mph. Winds will quickly wane Friday evening and become light overnight. Impacts: We have not seen a lot of rain in the Western Columbia Basin in the last 7 days and we do not anticipate any rain with the incoming front. Winter wheat has emerged but potato fields have recently been harvested. If we get sustained winds of 25 mph with gusts 35-40 mph for a few hours over a recently harvested field, cannot rule out some patchy blowing dust but overall, the threat is much lower than previous events this fall. The winds will also lead to choppy lakes for any water bodies across the Basin for those who may have plans for boating. Lastly loose objects may blow around so be sure to secure any empty garbage cans or other light-weight objects. /sb Saturday to Thursday: Dry, seasonal weather is expected through early next week, but a change start to emerge for the latter part of next week. First high pressure builds in, with the ridge axis coming onto Pacific coastline by late Saturday and translating toward the northern Rockies by Monday. Some middle to high clouds spill over the top of the ridge Saturday before they clear out for Sunday and Monday. However the tricky part remains the lower level moisture and the potential for stratus and/or fog. Confidence points to a threat over the eastern third of WA and ID Saturday morning, especially in the sheltered valleys and the southeast CWA. Confidence starts to wane after that as models diverge. The NAM holds moisture in and sloshes it west-northwest toward the Upper Columbia Basin, northeast WA and ID and eventually toward the Cascades and northern valleys between Saturday afternoon and Sunday. The GFS shows a similar trend but it is not as expansive. So this will be monitored. This may impacts temperatures, especially if the stratus holds on, but overall models forecast temperatures pushing above normal through this period. Between Monday night and Thursday the ridge axis shifts east and Pacific systems start to move in. A weak wave passes around Tuesday, with limited shower chances and some increase in clouds. A more substantial system moves inland between Tuesday night and Thursday. This comes with a moisture a modest moisture fetch in the west to southwest flow on a strong 160kt jet. This will mean a good chance of precipitation and increased winds. In this flow pattern models point to the Cascades and Idaho Panhandle as having the best chance for more significant precipitation. Models are pointing to the 80 percentile for precipitation near the Cascade crest for Wednesday. So this will have to be monitored for rises may be possible on places like the Stehekin River. Snow levels will initially be high enough through Wednesday to not have many impacts, but by Wednesday evening into Thursday morning the threat of snow moves toward passes levels and could cause travel impacts, especially the Cascade crest. Overall precipitation chances retreat to the mountains and far SE WA/lower ID going into Thursday. Winds will also be on the rise with this system, with the stronger threat focused around Wednesday with gusts in the 30 mph range or so possible. Temperatures are expected to remain Wednesday, then start to push down by Thursday. After that we may be looking for even cooler temperatures going into next weekend (in the 8-14 day period), with some snow potential returning to the valleys but that is still a ways out to have much confidence. /Cote` && .AVIATION... 00Z TAFS: Clear skies have returned to the region as high pressure buckles northward this evening. A strong cold front is approaching from the west but will not cross into E WA until after 10-12z. Prior the frontal arrival Friday morning, light winds and clear skies will bring the potential for a few hours of radiational fog around Spokane, Cd`A, Colville, Sandpoint, and Kellogg. Confidence is not extremely high this will impact the main terminals. A low- level jet develops ahead of the cold front with a moderate threat for LLWS between 12z-17z or generally with the frontal passage. A few showers also expected to develop with the front. As winds surface behind the front gusts 25-35kts will remain possible through 00z Friday afternoon. Isolated gusts closer to 40 kts will be possible in the mountains and upper reaches of the Columbia Basin. Band of precipitation expected to pass through ID fairly quick but could lead to on and off mountain obscurations along the Cascade Crest. /sb && .PRELIMINARY POINT TEMPS/POPS... Spokane 34 55 27 49 26 53 / 0 20 0 0 0 0 Coeur d`Alene 34 53 29 47 28 53 / 0 30 0 0 0 0 Pullman 35 54 30 49 28 55 / 0 40 0 0 0 0 Lewiston 40 61 37 54 35 59 / 0 10 0 0 0 0 Colville 29 54 24 49 23 53 / 0 20 0 0 0 0 Sandpoint 33 48 30 44 28 49 / 0 60 0 0 0 0 Kellogg 38 51 32 46 33 56 / 0 50 10 0 0 0 Moses Lake 34 62 27 53 28 56 / 0 0 0 0 0 0 Wenatchee 40 56 34 53 34 55 / 0 10 0 0 0 0 Omak 35 53 29 51 30 52 / 0 10 0 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Air Stagnation Advisory until 11 AM PDT Friday for Central Panhandle Mountains-Lewis and Southern Nez Perce Counties- Lewiston Area-Northern Panhandle. WA...Air Stagnation Advisory until 11 AM PDT Friday for East Slopes Northern Cascades-Northeast Mountains-Okanogan Highlands- Okanogan Valley-Waterville Plateau-Wenatchee Area. && $$

000 FXUS66 KPDT 292131 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 231 PM PDT Thu Oct 29 2020 .SHORT TERM...Today through Saturday night...High pressure ridge axis over our area will lead to the warmest day of the week, as high temps climb into the low 70s throughout central OR and the Basin, with highs in the low to mid 60s in WA as strong surface inversions prevail despite robust daytime heating. Rest of Thursday will be quiet before a shortwave moves through the PacNW during the early morning hours of Friday, bringing chances for light rain for the WA Cascade crests and the Blue Mountains, ending before Friday afternoon. Friday will be breezy for the rest of the CWA, with gusts eclipsing 30 and up to 40 mph for the Basin and Columbia River Gorge, as well as the Kittitas Valley. Guidance not confident in advisory-level winds, so will avoid headlines for now, but still expect a windy Friday for most of the area. Highs will drop into the low 60s for most of the area, expect for the Basin, where winds will mix out inversions and allow for better daytime heating, with highs in the mid 60s. Ridging will build back in by the evening of Halloween, keeping conditions mild and dry through early next week. .LONG TERM...Sunday into next weekend...Sunday into Tuesday to feature transiting just south of the region lending influence over the area. Skies will be clear to mostly clear with temperatures ranging from mid 50s in the Basin and mtns to about 70 in Central OR, closer to ridge axis, by Monday afternoon. Tuesday will be a transition day as downstream development across the Pacific nudges an active jet over us. This will bring breezy conditions down to the surface by Wednesday afternoon, clouds, and Cascade showers, particularly in WA Cascades. This generally unsettled pattern expected to last until roughly Friday when our next deep trough and associated low pressure system sweep the area. Details for this system are still quite a bit fuzzy in model guidance, but confidence is tepidly increasing that week 2 will begin with cold dome of air in place as next weekends system retreats. 76 && .AVIATION...00Z TAFs...VFR conditions to prevail through period with exception of the possibility of some light fog/BR possible in early morning hours at PSC. Otherwise, light winds and mostly clear skies expected into tomorrow morning. Tomorrow during the day, ceilings will drop slightly as a modest system sweeps the area, though VFR conditions still expected. Main impact will be breezy winds, both at the surface and aloft. Afternoon winds will be strongest through Columbia Basin terminals. 76 && .PRELIMINARY POINT TEMPS/POPS... PDT 39 62 32 55 / 0 10 0 0 ALW 43 62 35 56 / 0 20 0 0 PSC 39 65 34 54 / 0 0 0 0 YKM 35 63 30 57 / 0 10 0 0 HRI 39 65 34 58 / 0 0 0 0 ELN 39 57 33 53 / 0 20 0 0 RDM 35 64 28 62 / 0 0 0 0 LGD 33 61 30 56 / 0 20 0 0 GCD 38 66 31 63 / 0 0 0 0 DLS 43 61 37 58 / 0 10 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...None. WA...Air Stagnation Advisory until 11 AM PDT Friday for WAZ026-027- 520-521. && $$ SHORT TERM...74 LONG TERM....76 AVIATION...76

000 FXUS65 KREV 292036 AFDREV Area Forecast Discussion National Weather Service Reno NV 136 PM PDT Thu Oct 29 2020 .SYNOPSIS... High pressure will prevail over eastern California and western Nevada for the upcoming week. Above average high temperatures will continue through the middle of next week, with seasonably cool nights. Winds will remain generally light with no rain or snow expected. && .DISCUSSION... Main forecast changes were related to haze for southern Mono County where some smoke is expected to filter through mountain passes off of the Creek Fire. Hi-res models show best potential for haze through Friday afternoon with unconsolidated flow allowing for a drainage of smoke into portions of southern Mono County mainly this afternoon and again Friday afternoon. The severity of smoke infiltration does not appear to be as bad as recent weeks, but some air quality degradation can be expected. Otherwise, high pressure will mostly dominate the weather pattern for Nevada and California. Expect light winds, moderate to strong morning inversions, and above average temperatures to persist through the next 6 days or so for most locations. Air quality for urban centers could see some issues given the strength of inversions and build-up of pollutants. Far northeastern California and extreme northern Nevada will see an uptick in wind speeds towards the Oregon border for Friday. A passing wave in Oregon will be responsible for the increase in speeds with winds generally gusting 20-25 mph. There could be a brief period of stronger gusts in wind prone spots that could lead to some fire weather concerns; please, see the Fire Weather section below for details. Forecaster focus for more significant weather remains on the horizon in the 7-10 day period. A significant number of deterministic and ensemble model members have a consensus that a strong trough will drop out of the Pacific Northwest in this timeframe. This trough could bring strong wind gusts, more widespread fire weather concerns, and possibly some precipitation. Boyd && .AVIATION... Light, mainly terrain driven winds are expected through tomorrow morning. Smoke or haze is possible into the Mammoth/MMH vicinity this evening and again Friday afternoon as models show a light push of southwesterly winds from the Creek Fire. Possibly into MVFR at times but overall keeping TAF at VFR haze until proven otherwise. Trough swinging through the Pac NW on Friday will help kick up the winds tomorrow afternoon and evening, mainly SVE-WMC northward. Mountain waves downwind of the Warner Range are possible. Elsewhere including Reno-Tahoe we`re just expecting a slight increase in W/NW breezes Friday afternoon. The upcoming weekend looks like a great one for flying with high pressure building in, yielding light E/NE winds for the most part along with excellent visibility. -Chris && .FIRE WEATHER... Trough and cold front swinging through the Pac NW Friday will help increase winds during the afternoon and evening hours. Only area we`re concerned with regarding fire weather is closer to the Oregon border where pressure gradient is tighter: north parts of zones 270 and 458. Could see a few hours of near-critical winds and low humidity, but mainly wind prone areas. Will simply headline in FWF. Not widespread nor long enough duration for warnings. As a heads up, long range simulations are trending toward our first autumn storm late next week that could bring fire weather issues to the region. Friday 11/6 is the current leading scenario for potential critical winds. Much colder air and a chance for wetting rain showers follows into that weekend, but this far out it`s pretty low confidence. -Chris && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$ For more information from the National Weather Service visit... http://weather.gov/reno

000 FXUS66 KSTO 292014 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 114 PM PDT Thu Oct 29 2020 .SYNOPSIS... Light winds, above average temperatures, and very dry conditions are expected through early next week. && .DISCUSSION... GOES-West visible imagery reveals clear skies throughout nearly all of northern California. The only sign of clouds is along the immediate Pacific coast as well as offshore. The sunny conditions are allowing temperatures to warm into the low/middle 70s this early afternoon across the Sacramento Valley. By the time the afternoon concludes, communities in the Sacramento and northern San Joaquin Valleys will max out in the upper 70s to low 80s, or about 5 to 10 degrees above late October climatological normals. Upper level ridge just off the West Coast will provide continued dry and above normal temperatures through the weekend and into early next week. The mostly clear skies, dry conditions, and decreasing daylight hours will allow for efficient radiational cooling during the overnight hours in the Valley with sunrise temperatures in the 40s. Rowe && .EXTENDED DISCUSSION (Monday THROUGH Thursday)... Unseasonably warm and dry weather is expected to continue through the extended period as upper level ridging remains in place over California. Daytime temperatures are forecast to remain around 10 to 15 degrees above daily normals generally peaking in the upper 70s to low 80s across the Valley and 50s to 70s across the mountains. Cool overnight temperatures will continue with Valley lows in the upper 40s to low 50s with 30s to 50s across the mountains. Ensemble models indicate the upper level ridging will flatten by midweek as a weather system moves through the PacNW. The main impact to interior Northern California will be a slight increase in onshore flow and slightly rising relative humidity. Otherwise, all precipitation is expected to remain north of the forecast area with this system. Ensembles continue to indicate the possibility of another weather system moving south from the Gulf of Alaska into California late next week into the weekend that could bring a chance of precipitation to Northern California. Details remain fuzzy at this time, so check back for forecast updates. HEC && .AVIATION... VFR conditions over interior NorCal next 24 hours. Winds generally less than 12 kts. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$

000 FXUS65 KMSO 292105 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 305 PM MDT Thu Oct 29 2020 .DISCUSSION...Sunny skies, except for some morning fog in the lower valleys, prevail across the Northern Rockies today. Temperatures warmed up quite nicely: into the 50s and even lower 60s in some spots. There were a couple of exceptions where the inversion did not lift, namely Missoula, where temperatures have struggled to reach 40 degrees. Expect one more night of high pressure, valley inversions, and resultant valley fog. A weather disturbance will move through the Northern Rockies Friday afternoon through Saturday morning. As it does so, expect breezy conditions to develop with wind gusts to 25 mph, with some locally higher gusts to 35 mph. A Lake Wind Advisory has been issued for Flathead Lake, as these breezy conditions will bring choppy conditions to the lake through the evening. The other impact from this system will be showers developing along the frontal passage. These showers will move from northwest Montana through southwest Montana between early afternoon and early evening. Showers should remain as rain in valleys overall, however any remaining cold pockets could see a mix of snow (confidence is low). Saturday afternoon, a ridge of high pressure will quickly redevelop and persist through Tuesday. Expect dry weather with at or above seasonal temperatures. The stable air under the ridge may lead to increasing stagnant air and the potential for valley fog once again. A transition to a moist westerly flow aloft is expected around the middle of next week, which would result in an increase in moisture, especially in the mountains. Late next week, models remain consistent showing a low pressure trough amplifying over the western US. This would open the door for colder air and a potential for valley and mountain snow to make a return. && .AVIATION... Strong valley inversions will persist through 30/1800z. Expect a redevelopment of fog after 30/0900z at KGPI and KMSO persisting through 30/1600z. KSMN and KBTM can expect VFR conditions through 30/1800z. A strong cold front will move through the Northern Rockies Friday afternoon. The biggest impact from this front will be westerly winds gusting 15-25 mph through 31/0200z. Showers are also possible along the frontal passage which may temporarily lower visibility and ceilings. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...Air Stagnation Advisory until noon MDT Friday Bitterroot/Sapphire Mountains...Flathead/Mission Valleys... Kootenai/Cabinet Region...Lower Clark Fork Region... Missoula/Bitterroot Valleys...Potomac/Seeley Lake Region... West Glacier Region. Lake Wind Advisory from noon to 8 PM MDT Friday Flathead/Mission Valleys. ID...Air Stagnation Advisory until 11 AM PDT Friday Lower Hells Canyon/Salmon River Region...Northern Clearwater Mountains...Orofino/Grangeville Region...Southern Clearwater Mountains. && $$

000 FXUS65 KBOI 292048 AFDBOI Area Forecast Discussion National Weather Service Boise ID 248 PM MDT Thu Oct 29 2020 .SHORT TERM...Tonight through Saturday night...Warm, dry weather with light winds will continue until midday Friday. Surface cold front and upper trough will come in from the northwest Friday afternoon and evening with breezy west/northwest winds. Gusts to 25 mph in the Snake basin Friday evening. Chance of rain and snow showers only in northernmost mountains as the front passes. Other areas will see increasing clouds. Clearing Friday night with gradually decreasing winds. Saturday will be sunny with light west winds and about ten degrees cooler than Friday, under northwesterly flow aloft. Saturday night looks clear and a little colder than Friday night due to calmer wind. Sunday will be sunny and warmer as the upper ridge rebuilds. .LONG TERM...Sunday through Thursday...An upper ridge will build over the western U.S. over the weekend and into early next week. Temperatures will stay roughly 5 to 10 degrees above normal as conditions remain dry and calm. A longwave trough will pass over the Intermountain West mid-week, bringing a series of weak systems across the area on Wednesday and Thursday. Models suggest most of the precipitation will stay to the north of the CWA, but a chance of mixed precip remains for the northern mountains on Wednesday and Thursday. && .AVIATION...VFR. Surface winds generally variable 10kt or less. Winds aloft at 10k feet MSL: NW 15-25kt becoming W-SW 10-20kt this evening. Weekend Outlook...VFR conditions through the weekend with light winds and mostly clear skies. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...None. && $$ www.weather.gov/Boise www.facebook.com/NWSBoise www.twitter.com/NWSBoise SHORT TERM...LC LONG TERM....AL AVIATION.....AL

000 FXUS65 KLKN 292208 AFDLKN Area Forecast Discussion National Weather Service Elko NV 308 PM PDT Thu Oct 29 2020 .SYNOPSIS...Sunny and seasonably warm days with crisp nights continue for the next few days. && .SHORT TERM...Tonight through Saturday No low/mid level moisture accompanies this positive tilted diffused trough that is over Nevada today and tonight. Nocturnal inversions will be very shallow, resulting in large diurnal temperature swings from daybreak to late afternoon. A progressive short wave races across the northern inter-mountain region that brings cooler air into northern NV on Saturday. Ahead of the short wave, WSW breezes in the 15-20 mph range are expected north of I80 Thursday afternoon. .LONG TERM...Saturday night through next Thursday Dry weather is expected to prevail through the extended, although there are subtle hints of transitioning into a pattern change by Thursday. Main westerlies stay north of Nevada with blocking pattern covering the West (high pressure over the Pacific Northwest but closed low circulation along the SoCal coast). This pattern breaks down middle of the week with progressive westerly flow punching into the Pacific Northwest. By Thursday, the westerlies sag southward with an increase of gradient wind on Thursday across the northern NV. Temperatures stay well above seasonal averages. && .AVIATION... SKC conditions prevail with no aviation hazards expected. Local G25kts will be possible north of KWMC-KBAM-KEKO after 20Z Friday. && .FIRE WEATHER... Dry weather with low humidities continuing for the next several days. For the northern fire weather zones Friday afternoon (437, 438, 469, 470), gradient winds increase from WSW with local gusts to 25 mph (ridgetops to 30 mph) for 1-2 hours, conditions stay below critical thresholds. For next Wednesday and particularly Thursday, gradient winds may increase and may approach critical thresholds. && .LKN WATCHES/WARNINGS/ADVISORIES... None. && $$ 88/88/88/88