000
FXAK68 PAFC 250107
AFDAFC
Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
507 PM AKDT Wed Apr 24 2024
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: This
afternoon through Saturday afternoon)...
The forecast remains on track, with few major changes. Quiet
weather prevails for all but Kodiak Island and southern/eastern
Kenai Peninsula, where fronts will bring light to moderate
precipitation. No major hazards are currently being monitored.
Diving into the details... most of the Southcentral Mainland is
experiencing nearly cloud-free skies under a ridge of high
pressure, though daytime heating and instability are producing
cumulus clouds in Western Kenai Peninsula and along area
mountains. Daytime heating is also contributing to gusty winds
through Knik River Valley and into Palmer, as well as along
Turnagain Arm. Meanwhile, thicker cloud cover is present over
southern Kenai Peninsula and Kodiak Island, where a front is
presently located. The front will remain nearly stationary through
Thursday evening, leading to precipitation accumulations of about
another quarter to half inch for Kodiak Island.
By Thursday evening, an incoming shortwave will push the
aforementioned front into the Southcentral Mainland and bring a
North Pacific low towards Kodiak Island. The arrival of the front
will bring increasing cloud cover and an end to the recent spell
of sunnier weather for the Mainland. With the front weakening as
it moves north, expect precipitation to remain light and largely
confined to Eastern Kenai Peninsula. Still, a few stray showers
are not out of the question for the remainder of the area. For
Kodiak Island, the North Pacific low will bring with it a decent
slug of moisture. Expect additional precipitation amounts of about
an inch for eastern Kodiak Island, with up to about a half inch
for the western/leeward side of Kodiak Island.
The good news is that these wetter conditions won`t persist for
long. By Saturday, precipitation will begin tapering off as the
North Pacific low pivots southwards, leading to quieter weather
for the weekend.
-KC
&&
.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3)...
A large vertically stacked low continues to take up real estate
over the Bering this evening. Over the next couple of days the low
is expected to fill in and weaken while shifting southeastward
across the Eastern Aleutians through Friday. Small craft winds to
around 30 knots are common on the backside of the low and extend
into the Western and Central Aleutians, within general cyclonic
flow around the low. This swath of marginally elevated winds will
shrink in coverage through tonight while shifting between the
Central and Eastern Aleutians by Thursday night. Conditions across
the Bering become more benign Friday and Saturday with elevated
northerly winds only expected through Alaska Peninsula.
Elsewhere, scattered rain showers are ongoing over Greater
Bristol Bay. Shower activity extends northward into eastern
portions of the Kuskokwim Delta and stretches as far east as
Aniak. This activity is associated with remnants of an occluded
front that has now shifted inland of the coast. Showers will
remain possible into Thursday, but activity over the Kuskokwim
Delta is expected to shift eastward into the Lower Kuskokwim
Valley. Rain chances linger into Friday and finally diminish by
the start of the weekend. Afternoon high temperatures for
southwest Alaska will range from the mid 30s to upper 40s the next
few days while overnight lows are expected stay in the low to mid
30s.
&&
.LONG TERM FORECAST (Days 4 through 7: Sun through Wed)...
The low that is currently over the Bering Sea will have meandered
into the Eastern Gulf of Alaska for Sunday and slowly drift south
along the western coast of North America through the early half
of the week. A ridge will likely build behind the low across
Southcentral. Embedded easterly waves could lead to brief showers
in the Copper River Basin each day. A larger, embedded shortwave
is possible for Tuesday along the ridge, but any moisture
associated is still expected to be light and or showery.
Out west, a front is moving through the Bering and across the
Aleutians. For Sunday, the front will be located around the
central to eastern Aleutians and will reach the Pribilofs before
weakening and being replaced by a larger and stronger occluded low
Monday. This low will bring more moisture into the Bering Sea and
Aleutians. Storm force winds look likely for the western
Aleutians Monday morning, weakening to gales by Tuesday. Its front
reaches the Southwest Alaska as early as Tuesday and spreading
the bulk of the moisture to Southwest, the Alaska Peninsula, and
Kodiak Island for Wednesday. Timing of the precipitation will
depend on the position of synoptic feature, the progression, and
orientation of the front. Although the overall synoptic setup is
in better agreement for the extended period, the details could
mean bigger differences in the QPF and wind fields across the
Bering and Southwest Alaska.
rux
$$
.AVIATION...
PANC...VFR conditions will persist. Southeast winds 10 to 15 kts
are expected to develop over the airport late this afternoon into
the evening. Winds are then expected to become light and variable
again overnight. SE winds are also likely to return Thursday
afternoon and evening.
&&
$$
000
FXAK69 PAFG 250025
AFDAFG
Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
425 PM AKDT Wed Apr 24 2024
.SYNOPSIS...
Clear and quiet weather continues across Interior Alaska. Areas of
clouds and light rain continue along a front stretching from the
Bering Strait to Nome to Aniak. Low clouds and fog persist on the
North Slope, with blizzard conditions expected to begin from
Nuiqsut east starting Thursday morning.
&&
.DISCUSSION...
Analysis and Model Discussion...Strong ridging continues to build
over northern Alaska while a vertically stacked low persists over
the Bering Sea. This is bringing areas of light precipitation to
the West Coast and very sunny, clear, and calm weather to the
Interior. Clouds are trapped beneath high pressure on the Arctic
Coast with very low ceilings and low visibility. The low in the
Bering Sea will shift into the Gulf of Alaska by Friday night,
bringing an end to the light precipitation on the West Coast.
Ridging will strengthen over the Interior and North Slope through
Thursday, then weaken slightly through the weekend. A building
area of surface high pressure in the Arctic will bring strong east
winds and blizzard conditions to the central and Eastern Arctic
Coast on Thursday and Friday.
Models are in good agreement on the forecast through the short
term period. By Saturday night, the ECMWF is slightly slower than
the consensus NAM/GFS/Canadian solutions in moving the low in the
Bering Sea into the Gulf of Alaska. We will use a blend of models
for the forecast package, and trend toward the GFS starting late
Saturday.
West Coast and Western Interior...A weak front remains stationary
from the Bering Strait to Nome to Aniak and is bringing areas of
clouds and light rain. Precipitation will intensify slightly
overnight tonight, but is still expected to be mostly light.
Precipitation will diminish Friday. Winds will be mainly offshore
at 15 mph or less with high temperatures in the 30s along the
coast and in the 40s inland.
Central and Eastern Interior...Very quiet and pleasant weather
continues across the area. High temperatures will trend a couple
of degrees warmer on Thursday, into the upper 50s to mid 60s.
Highs Friday through the weekend will trend back to the low 50s by
Sunday. Light southerly gap winds of 15 to 20 mph are expected
through Alaska Range passes Thursday and Friday.
North Slope and Brooks Range...Areas of fog and low clouds remain
trapped beneath high pressure along the Arctic Coast with clear
skies in the Brooks Range. Building high pressure will keep these
low clouds in place across the Arctic Coast. East winds increase
to 25-35 mph with gusts 45 to 50 mph across the Central and
Eastern Arctic Coast starting Thursday morning and continuing
through Friday evening. This will bring blizzard conditions to the
area. Temperatures will range from the upper 30s for highs along
the north side of the Brooks Range tomorrow to the single digits
below zero for lows along the Arctic Coast Saturday morning.
Coastal Hazard Potential Days 3 and 4...None.
Extended Forecast For Days 4 Through 7...Ridging will persist over
northern Alaska, bringing continued fair weather. The ridging will
be weaker than this week, so temperatures will trend back to near
or slightly below normal. Any precipitation is expected to be very
light.
&&
.FIRE WEATHER...Relative humidities will reach critical levels
(25% or lower) Thursday and Friday across the Tanana Valley. The
lowest RHs will be near and south of Delta Junction at around 15%.
South winds through Alaska Range passes will gust to around 25 mph
early Thursday morning through Friday morning, with poor RH
recovery expected in this area Thursday night. High temperatures
will be in the mid to upper 50s near Delta Junction and in the low
to mid 60s across the rest of the middle Tanana Valley.
&&
.HYDROLOGY...River and lake ice continues to decay across the
Interior. Use extreme caution if traveling on ice.
&&
.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Blizzard Warning for AKZ804-805.
PK...Brisk Wind Advisory for PKZ812-858.
Brisk Wind Advisory for PKZ813-859.
Brisk Wind Advisory for PKZ814-815-860-861.
Brisk Wind Advisory for PKZ851.
&&
$$
CHRIEST
000
FXAK67 PAJK 242255
AFDAJK
Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
255 PM AKDT Wed Apr 24 2024
.SHORT TERM.../ through Thursday night / A low over central
British Columbia is rotating bands of the showers westward to the
border mountain range and into southern and central panhandle. PoP
levels for showers diminish to 20-30 percent by Thursday morning,
then dry starting Thursday night.
A weak ridge of high pressure over the eastern gulf and western
Canada has holding the weather at bay for most of the area for a
couple of days, and will continue to the start of the weekend.
Winds through the panhandle should be 15 kt or less, daytime
seabreezes are possible which means winds may be flip flopping
direction. Morning fog develop is likely as well from Yakutat,
Cross Sound and western Prince of Wales Island.
.LONG TERM...
Through the long term a Rossby wave will shift towards the
western seaboard carrying an open 500mb trough and associated
surface low into the Gulf. While Friday still looks quite
agreeable, light winds and warm temperatures, expect southeasterly
winds to increase 22-27 knots south of Cape Fairweather into
Dixon Saturday morning along with a southerly 8 to 12ft fresh
swell. The highest of these significant heights look to remain
south of Cape Decision. For this weekend, main areas of concern
for mariners operating in smaller vessels in our waters is Cross
Sound south along the coast of Prince of Wales, southern Chatham,
and southern Clarence into Dixon Entrance.
While the overall theme remains the same for this system,
clusters are starting to highlight an eastward shift of the
surface low over the weekend, with a slightly steeper pressure
gradient stretching into Haida Gwaii. These features in the
ensembles could increase southerly winds west of Haida Gwaii and
in Hecate Strait, resulting in an increase of the significant wave
heights moving into Dixon and southern Clarence; have adjusted
the forecast accordingly.
Regarding precipitation and guidance analysis, we can take two
stances; one of the realistic optimist, while the other is the
defensive pessimist. Regarding the former, guidance from CW3E
Scripps highlights an uptick of IVT moving into Queen Charlotte
sound, with members starting to bring more moisture north into the
southern Panhandle. While amounts and rates still look abysmal,
we could see a bit more rain than our previous forecasts, perhaps
1 to 1.5 inches or so of light rain accumulation through the
weekend into Tuesday morning.
Switching to the defensive pessimist, while a few members of IVT
guidance are bringing rain north, the majority of solutions
continue to keep higher IVT values further south, with less than 1
inch of total rainfall more likely into Monday. To put this
pessimism into context, precipitation sites in the south are
reporting 2 to 4 inches of rainfall over the month, where April
normals for Ketchikan are around 10 inches. For now, the published
forecast indicates less than 1 inch totals over the weekend. No
matter our attitudes on how this metaphorical milk is spilled, the
central and southern Panhandle will likely finish the month far
under normal precip amounts.
&&
.AVIATION...Widespread VFR conditions for the northern panhandle
through the day Wednesday. Southern half of the panhandle will
continue to see lingering showers and associated lower ceilings
through Wednesday night before beginning to thin out a bit. Areas
with thinning cloud cover overnight however are likely to see
another batch of fog, such as on Prince of Wales and also up north
at Yakutat. Similar to Wednesday, these lower conditions in the
morning should quickly give way to VFR conditions by mid to late
Thursday morning. No significant wind concerns.
&&
.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...None.
&&
$$
SHORT TERM...Bezenek
LONG TERM....AP
AVIATION...STJ
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