Severe Weather - Flooding

068
ACUS01 KWNS 181239
SWODY1
SPC AC 181237

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0637 AM CST Mon Jan 18 2021

Valid 181300Z - 191200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Isolated, non-severe thunderstorms are possible during the early
morning Tuesday across a portion of central to east Texas.

...Central to east TX...
Persistent low-level warm theta-e advection centered around 850 mb
ahead of a cold front that will advance southeast across the
southern Great Plains should result in at least isolated showers
developing overnight into Tuesday morning. Guidance generally
suggests meager elevated buoyancy will become prevalent after 06Z.
However, zonal mid-level flow and lack of stronger ascent aloft
suggest a relatively warm/dry profile atop the elevated buoyancy
layer may mitigate appreciable deepening of the showers.
Nevertheless, towards the pre-dawn hours, the potential for charge
separation is not entirely negligible. Have added a thunderstorm
area with probabilities appearing to be between 10-20 percent.

..Grams.. 01/18/2021

$$

293
ACUS02 KWNS 180637
SWODY2
SPC AC 180635

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1235 AM CST Mon Jan 18 2021

Valid 191200Z - 201200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Non-severe thunderstorm development will be possible across parts of
the southern Plains from Tuesday afternoon through Tuesday night.

...DISCUSSION...
An upper-level low will retrograde southwestward across southern
California on Tuesday as zonal mid-level flow remains from the
southern Plains to the Eastern Seaboard. At the surface, a cold
front will advance southward across south-central and east Texas.
Surface heating and increasing low-level convergence along the front
could be enough for isolated thunderstorm development Tuesday
afternoon, mainly in south-central Texas. Instability will likely be
insufficient for a severe threat. Elsewhere across the continental
United States, thunderstorms are not expected Tuesday or Tuesday
night.

..Broyles.. 01/18/2021

$$

000
NWUS53 KAPX 161740
LSRAPX

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GAYLORD MI
1240 PM EST SAT JAN 16 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1000 AM     SNOW             MANTON                  44.41N 85.40W
01/16/2021  E3.0 INCH        WEXFORD            MI   PUBLIC

            24 HOUR TOTAL FROM SOCIAL MEDIA.

1000 AM     SNOW             4 ENE SOUTH BRANCH      44.48N 83.80W
01/16/2021  E4.0 INCH        IOSCO              MI   PUBLIC

            24 HOUR ESTIMATE FROM SOCIAL MEDIA.

1000 AM     SNOW             MCBAIN                  44.19N 85.21W
01/16/2021  E5.5 INCH        MISSAUKEE          MI   PUBLIC

            24 HOUR ESTIMATE FROM SOCIAL MEDIA.

1000 AM     SNOW             1 NE MANTON             44.42N 85.38W
01/16/2021  E3.5 INCH        WEXFORD            MI   PUBLIC

            24 HOUR SNOW. ESTIMATE FROM SOCIAL MEDIA.


&&

$$


FEF

000
FXUS63 KAPX 181138
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
638 AM EST Mon Jan 18 2021

.NEAR TERM...(Today through Tonight)
Issued at 339 AM EST Mon Jan 18 2021

...Increasing lake effect snow tonight onward...

High Impact Weather Potential: Minimal today. Accumulating lake
effect snow for the snowbelts tonight through Tuesday.

Pattern Synopsis/Forecast: Overnight composite analysis reveals
large scale troughing encompassing a large portion of the CONUS,
getting reinforced by sharp short-wave ridging building along the
west coast. One embedded wave is progressing out of the Ohio
Valley toward the mid Atlantic coast with subtle short-wave
ridging across the western lakes region for the moment. Weakening
low level cyclonic flow/lake aggregate troughing still lingers
across the western lakes. But resultant persistent light snow
across the region appears to finally be winding down.

Upstream, additional short-wave energy and substantially colder
air is loading up across central Canada...poised to slide down
into the northern lakes region over the next few days and sure to
bring accumulating lake effect snow.

Details: Lake aggregate troughing is expected to linger across
the region today. Associated low level convergence combined with
modest over lake instability and daytime heating will likely
bring another expansion of light snow showers across northern
Lower Michigan through the day, along with minor (under and inch)
type snow accumulations. Otherwise, not a bad day overall...by mid
January standards...with lighter winds, and daytime temperatures
on par with normal readings.

Starts to get a lot more interesting tonight and heading into
Tuesday. Aforementioned short-wave energy and pocket of colder air
(mid to high negative teens H8 temps by Tuesday morning) dives
into the northern lakes region later tonight, spinning up stronger
surface low pressure over Lake Superior along the lake aggregate
trough. Bufkit forecast soundings reveal what you`d expect in
response...substantially increasing inversion heights/convective
depth and lake induced CAPE values climbing to near 500 J/KG
overnight. This should gin up some decent lake effect snow showers
off Lakes Superior and Michigan and snow accumulations already pushing
into advisory criteria in the snow belts by Tuesday morning.

Decent lake snow showers continue Tuesday into Tuesday night (see
below) and it appears we will be into solid winter weather
advisory headline criteria from later tonight through Tuesday
night...particularly with gustier W/NW winds and some blowing snow
developing. But will let day shift make final tweaks and headline
decisions.

&&

.SHORT TERM...(Tuesday through Thursday)
Issued at 339 AM EST Mon Jan 18 2021

High impact weather potential: Accumulating lake effect/enhanced
snow is possible Tuesday into Wednesday, especially across the
traditional snowbelt locations of eastern upper and northwest lower
Michigan. Maybe some freezing drizzle Wednesday afternoon through
Thursday?

Pattern synopsis and forecast:

Broad troughing will cover the eastern CONUS with a few separate
waves pinwheeling through the forecast area...producing synoptic
snow and enhanced by the lakes at times with 850mb temperatures of
-15 to -20C. A weak surface low will depart east of the forecast
area...setting up the beginning of this more active period. The cold
west-northwest to northwesterly flow will produce lake effect snow,
with the highest accumulations expected in the normal snowbelts of
northwest lower and eastern upper. These snows will be enhanced at
times with another upper wave and some deeper moisture moving
overhead Tuesday afternoon through Tuesday night. Forecast soundings
show inversion heights of just over 5kft with best moisture in the
DGZ. Winds will become a bit gusty Tuesday as the pressure gradient
tightens with the aforementioned weak surface cyclone departing to
our east and another wave approaches from the west...these gusty
winds will further exacerbate the snow, making for reduced
visibility and snow blowing across roadways. Winds back to more
southwesterly Wednesday as heights finally begin to increase and the
broad cyclonic flow is replaced with ridging. Although the lake
effect/enhanced snows will become greatly diminished there will be a
chance of an extended period of time with freezing drizzle either
mixing in or completely changing to freezing drizzle with heights
increasing aloft ahead of the approaching wave...and surface
temperatures remaining well below freezing Wednesday
afternoon/evening into Thursday. Looking at CIPS analogues and some
ensemble data along with what we came up with in our forecast
package tonight...wouldn`t doubt some of our favorable areas seeing
localized heavier amounts of 8"+ in northwest lower and eastern
upper by Wednesday afternoon/evening. Will continue to monitor the
ever-changing weather and update accordingly. Temperatures will be
normal to near normal for this time of the year, with highs in the
20s to near freezing and lows in the single digits and teens above
zero.

.LONG TERM...(Thursday night through Monday)
Issued at 339 AM EST Mon Jan 18 2021

High Impact Weather Potential: Monitoring late week system.

Confidence continues to increase in a relatively strong clipper
system moving across the far northern Great Lakes in the late
Thursday/Friday timeframe. A shortwave and associated speed max is
expected to dig down from western Canada into Midwest by Thursday,
providing strong forcing aloft to support the deepening of this
aforementioned clipper system as it slides into the region.
Precipitation on the front end of the system is expected to be
confined to the northern half of the area, while the main forecast
concern is expected to be the lake effect snow potential on the
backside. Details will become more clear as the week progresses.
Otherwise, temperatures will cool back down into the low to mid 20s
with cold advection behind the passing cyclone. Overnight lows next
weekend may drop back down into the single digits across northern
Michigan as well.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 638 AM EST Mon Jan 18 2021

Overall MVFR conditions persist across northern Lower Michigan,
with occasional breaks of higher CIGS/VFR conditions, which are
hard to forecast precisely. But generally MVFR conditions will be
the rule through the day with some light snow showers about the
region.

Colder air spills into northern Michigan tonight. This will get
the lake effect machine cranked up with heavier snow showers
impacting the snow belts...including TVC/PLN and MBL. MVFR and
periodic IFR conditions should be expected at those terminal
sites. Slightly better conditions at APN.

In addition to the snow showers, gustier W/NW winds develop
tonight and persist through Tuesday.

&&

.MARINE...
Issued at 339 AM EST Mon Jan 18 2021

Turning a bit more active for the next few days. Gusty west to
northwest winds develop later tonight and persist through Tuesday
night. Will be hoisting small craft advisories for many Lake
Michigan and Huron nearshore areas. Additionally, expect lake
effect snow showers to increase substantially on the lakes tonight
through Tuesday night, along with some freezing spray.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY from 5 AM Tuesday to midnight EST Tuesday
     night for LHZ345>348.
LM...SMALL CRAFT ADVISORY from midnight tonight to midnight EST
     Tuesday night for LMZ323-341-342-344>346.
LS...NONE.
&&

$$

NEAR TERM...BA
SHORT TERM...TL
LONG TERM...TL
AVIATION...BA
MARINE...BA

071
ACUS11 KWNS 161747
SWOMCD
SPC MCD 161747
MEZ000-162345-

Mesoscale Discussion 0022
NWS Storm Prediction Center Norman OK
1147 AM CST Sat Jan 16 2021

Areas affected...portions of northern/western Maine

Concerning...Heavy snow

Valid 161747Z - 162345Z

SUMMARY...Heavy snow will continue to develop northeast across the
discussion area through this afternoon.  Snowfall rates of around
one inch/hour will be possible.

DISCUSSION...Strong low-level southeasterly flow and resultant
warm/moist advection continue to support a large area of
precipitation north/east of a surface low over eastern MA at 17z.
Forcing for ascent associated with the warm advection will continue
to shift northeast through this afternoon, supporting a mix of
precipitation types across northern New England.

Across the discussion area, the higher elevations will generally
support snow as the dominant precipitation type, although periods of
mixed precipitation will be possible.  Forecast soundings from the
16z RAP and 12z NAM guidance show below freezing thermal profiles
and saturation/lift developing within the dendritic growth zone this
afternoon, and several hours of 1 to locally 2 inch/hour snowfall
rates will be possible.  This trend is supported by recent guidance
from the HRRR and HREF ensemble.

..Bunting.. 01/16/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...CAR...GYX...

LAT...LON   45277083 45787035 46187020 46467002 46536932 46026907
            45486947 45007024 44667073 44707091 44737097 44847099
            44987101 45097100 45257097 45277083