061

ACUS01 KWNS 050035

SWODY1

SPC AC 050033



Day 1 Convective Outlook

NWS Storm Prediction Center Norman OK

0633 PM CST Thu Dec 04 2025



Valid 050100Z - 051200Z



...NO SEVERE THUNDERSTORM AREAS FORECAST...



...SUMMARY...

A few thunderstorms are expected near/along the northern Gulf Coast

tonight.



...01z Update...



Low-amplitude short-wave trough is advancing east-northeast across

the lower MS Valley early this evening. A corridor of weak

convection is noted ahead of this feature from southeast LA into

southwest AL. The deepest, more robust updrafts over southeast LA

are generating a few flashes of lightning. Surface-based buoyancy is

not expected to materialize inland through sunrise, and any

thunderstorm activity near the Gulf Coast will be driven in large

part by warm advection, and should remain elevated. Midlevel

instability appears too weak to warrant any meaningful risk for

severe.



..Darrow.. 12/05/2025



$$






                

                        

065

ACUS02 KWNS 041729

SWODY2

SPC AC 041728



Day 2 Convective Outlook

NWS Storm Prediction Center Norman OK

1128 AM CST Thu Dec 04 2025



Valid 051200Z - 061200Z



...NO SEVERE THUNDERSTORM AREAS FORECAST...



...SUMMARY...

Severe storms are not forecast Friday.



...Synopsis...

Broad mid-level troughing over the eastern US is forecast to

continue Friday as several small-scale perturbations pass over the

Plains and Midwest. At the surface, a low will deepen over the

northern Rockies while a stalled front will remain in place along

the Gulf Coast. Behind the front, a cold and dry polar air mass will

largely preclude thunderstorm development over much of the US. The

exception will be along the central and northeastern Gulf Coast

where a few thunderstorms are possible early.



...Southern LA to the FL Panhandle...

Along the stalled front, a weak wave low is forecast to develop

across the northern Gulf ahead of a low-amplitude shortwave moving

out of the southern Plains. Convergence along the front and ahead of

this feature could allow the front to move inland a few miles Friday

morning. While not overly warm nor moist, modest destabilization

could support isolated elevated thunderstorms inland and closer to

the coast through midday. Strong flow aloft and backing along the

front could allow for a few transient rotating cells. This appears

most likely over parts of southern LA and the FL Big Bend where

storms closer to the front could potentiality be near surface-based

for a couple hours. However, given the weak buoyancy and few if any

surface-based storms inland for a longer duration, severe potential

remains too low for probabilities.



..Lyons.. 12/04/2025



$$






                

                        

285

NWUS53 KAPX 041452

LSRAPX



Preliminary Local Storm Report

National Weather Service Gaylord MI

952 AM EST Thu Dec 4 2025



..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...

..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....

            ..REMARKS..



1112 PM     Non-Tstm Wnd Gst 1 S Sault Ste. Marie    46.47N 84.37W

12/03/2025  M43 MPH          Chippewa           MI   AWOS



            AWOS station KANJ Sault Ste Marie -

            Municipal Airport.



0540 AM     Non-Tstm Wnd Gst 7 NNE Northport         45.21N 85.55W

12/04/2025  M41 MPH          LMZ344             MI   Mesonet



            Mesonet station GTLM4 6 NE Northport.





&&



$$












                

                        

599

FXUS63 KAPX 042338

AFDAPX



Area Forecast Discussion

National Weather Service Gaylord MI

638 PM EST Thu Dec 4 2025



.KEY MESSAGES...



- Light snow tonight with some lake enhancement in southwest flow

off Lake Michigan...round 1.



- More widespread snow Friday night with (maybe) some lake

enhancement off Lake Michigan...round 2.



- Windy and colder Saturday with lake effect snow showers returning.



- Another round of synoptic snowfall in the Sunday time frame.



- Alberta clipper around Tuesday? Maybe...



&&



.SHORT TERM /THROUGH FRIDAY NIGHT/...

Issued at 358 PM EST Thu Dec 4 2025



Pattern Synopsis/Forecast: Full latitude long wave trough

encompasses North America this afternoon...some impressive 500mb

height/temperature anomalies within the core of the trough over

Ontario/Quebec (-2 to -3 sigma standardized height anomalies/-48C

with the thermal trough).  Large scale pattern is amplified all the

way across the Pacific Basin...with -EPO ridging over the eastern

Pacific.  But things are shifting...trough axis is east of the upper

Lakes this afternoon as a strong PV anomaly (dynamic tropopause

below 600mb) rotates across southern Ontario/Quebec with height

rises just upstream.  Mid level warm advection already underway

across the upper Midwest and spreading into Wisconsin/ Michigan...

ahead of another short wave trough digging southeast out of Manitoba

(better defined at 700mb).



Surface analysis shows a 1035mb high centered over Iowa...in the wake

of yesterday`s cold front passage.  Sharp mesoscale troughing runs

southeast/northwest across Lake Huron/Lake Superior due to lake

heating.  Surface cold air was "horseshoeing" around the upper

Lakes...but an impressive textbook example of cold air draining off

the higher terrain east of Lake Superior and into eastern Upper

earlier this morning.  Winds at CYAM were gusting to 43kts from the

northwest before the wind flipped to northeast and the temperature

dropped 9F.  So even against that background flow the density current

was able to overcome that and dropped all the way into northern Lake

Huron.



Surface high over Iowa slides south of Michigan this evening...

swinging boundary layer winds to the southwest while upstream short

wave trough crosses Lake Superior during the early morning hours.

This will be followed by another short wave trough tracking farther

south than the previous one...arriving Friday night and pushing a

cold front across Michigan that will bring a renewed shot of cold

air for the weekend.



Primary Forecast Concerns:



Light snow tonight with some lake enhancement in southwest flow off

Lake Michigan...round 1: Backing low level winds already underway

this afternoon...which will push existing multiband convection east

and northeast and should get some southwest flow bands going on

northern Lake Michigan.  These look to be relatively shallow to

start but the cloud layer is within the DGZ thermal range with an

inversion height around 800mb.  Most of this activity should be

focused into eastern Upper and the tip of the mitt.  Isentropic

ascent will spread mid/high level moisture across roughly the

northern half of the forecast area this evening...but there is a dry

layer between the higher level clouds and the top of the CBL.  So

initially there won`t be seeder-feeder enhancement...but the column

is expected to moisten after midnight and some increase in low level

convergence which may be a signal of a more dominant band getting

organized.  Anticipating a boost in snow intensity into eastern

Upper and the Straits region overnight and into Friday morning.

Eventually looks like a band of snow will propagate southward across

northern Lower Friday (more on this below).



So for snow amounts in the enhanced areas do think that parts of the

eastern Upper plus Emmet county zones are going to be pushing

advisory criteria snowfall amounts (in the 3-6 inch range roughly

from midnight to noon).  Far northern Cheboygan county and westerly

Mackinac county will be close...but snowfall won`t be the only issue

with increasing southwest winds tonight.  Wind gusts of 30 to 40mph

are likely...so blowing and drifting snow will just add to the

impact (the drive along US-2 might not be much fun overnight).  Will

go ahead and hoist a Winter Weather Advisory for the zones mentioned

above (plus the islands)...will include Cheboygan county to avoid

getting to cute though it may not get "bad" there until late tonight.



More widespread snow Friday night with (maybe) some lake enhancement

off Lake Michigan...round 2: Approach of next short wave trough

Friday afternoon is expected to result in an increase in snowfall

coverage across northern Michigan.  Good dynamic forcing and steep

mid level lapse rates could surprise a bit from a synoptic QPF

standpoint.  But will see about the details of that...mid level

moisture may strip away overnight ahead of the cold front passage

(so maybe end with a period of freezing drizzle??).  Not as great a

lake enhancement signal off Lake Michigan Friday night but it is

still there and certainly won`t hurt the cause; shallow CBL mostly

at temperatures warmer than -10C may just add a lot more supercooled

droplets and riming potential to the equation...which would cut down

on SLR.  But certainly several more inches of snow in the cards for

eastern Upper/northwest Lower through 1200Z Saturday.



&&



.LONG TERM /SATURDAY THROUGH THURSDAY/...

Issued at 358 PM EST Thu Dec 4 2025



Primary Forecast Concerns:



Windy and colder Saturday with lake effect snow showers returning:

Gusty northwest winds will bring colder air into Michigan Saturday

in the wake of a morning cold frontal passage.  Does not look overly

impactful at this point (other than the fact that it won`t stop

snowing).  Temperatures probably steady or falling through the 20s

Saturday.



Another round of synoptic snowfall in the Sunday time frame: Another

short wave trough in the persistent northwest flow looks to arrive

Sunday and bring another round of widespread snow...followed by some

lake effect (again not looking overly impressive).  Another day of

highs in the 20s (normals this time of year are lower to mid 30s).



Alberta clipper around Tuesday?  Maybe...: Indications of such an

event but the details are all over the place.  But PoPs will be

increasing into the midweek period.



&&



.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...

Issued at 638 PM EST Thu Dec 4 2025



Worsening conditions late tonight CIU/PLN. Sw flow lake-

enhanced snow will develop and increase in coverage/intensity

over eastern upper and far northern lower MI. Expect CIU to

become IFR late tonight, and PLN Friday morning, in falling and

blowing snow. Conditions improve to MVFR in the afternoon.



For TVC/APN/MBL, VFR tonight, becoming MVFR cigs/vsbys with

light snow on Friday.



S to sw winds become blustery late tonight. Winds diminish a

bit Friday afternoon.



&&



.APX WATCHES/WARNINGS/ADVISORIES...

MI...Winter Weather Advisory from 11 PM this evening to 11 AM EST

     Friday for MIZ016-086>088-095-096-098.

     Winter Weather Advisory from 1 AM to 11 AM EST Friday for

     MIZ017.

MARINE...Gale Warning from 10 PM this evening to 11 AM EST Friday for

     LHZ345.

     Small Craft Advisory until 5 PM EST Friday for LHZ346>348.

     Small Craft Advisory until 5 AM EST Saturday for LHZ349.

     Gale Warning from 10 PM this evening to 11 AM EST Friday for

     LMZ323-341-342-344>346.

     Gale Warning from 11 PM this evening to 11 AM EST Friday for

     LSZ321.

     Small Craft Advisory from 11 PM this evening to 11 AM EST

     Saturday for LSZ322.



&&



$$



SHORT TERM...JPB

LONG TERM...JPB

AVIATION...JZ






                

                        

867

ACUS11 KWNS 030113

SWOMCD

SPC MCD 030112

MEZ000-NHZ000-030715-



Mesoscale Discussion 2249

NWS Storm Prediction Center Norman OK

0712 PM CST Tue Dec 02 2025



Areas affected...coastal northern New England



Concerning...Heavy snow



Valid 030112Z - 030715Z



SUMMARY...Moderate to heavy snow rates on the order of 1/2 to 1+

inches per hour are possible across southern Maine this evening,

with heaviest rates most probable near Down East coastal areas

closer to and after Midnight EST, as strengthening and gusty winds

contribute to reduced visibilities and blowing/drifting.



DISCUSSION...A deepening surface cyclone is forecast to continue an

east-northeastward migration, generally south through east of the

Cape Cod vicinity through mid to late evening.  This will be

accompanied by a zone of strengthening lower/mid-tropospheric

frontogenetic forcing to its north through northeast.  At

mid-levels, the Rapid Refresh indicates that this will shift across

southern Maine through southern New Brunswick, where forecast

soundings indicate that  strengthening lift in (roughly) the 600-500

mb layer may coincide with temperatures most conducive to large

dendritic ice crystal growth (around -15 C).



There is notable spread within and among the various model output

concerning these details, and potentially varying rates of cyclone

and upward vertical motion intensification.  However, in the

presence of sub-freezing thermodynamic profiles, guidance generally

indicates snow rates on the order of 1/2 to 1 inch per hour are

possible this evening across much of southern Maine.  Heaviest rates

appear most probable near immediate coastal areas of Maine,

particularly across Down East coastal Maine closer to and after

05-06Z, when strengthening and gusty east-northeasterly surface

winds may contribute to considerable blowing/drifting and reduced

visibilities.



..Kerr.. 12/03/2025



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



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



LAT...LON   43277133 44757076 45456714 44046610 43626951 43127081

            43277133