680

ACUS01 KWNS 241627

SWODY1

SPC AC 241625



Day 1 Convective Outlook

NWS Storm Prediction Center Norman OK

1025 AM CST Wed Dec 24 2025



Valid 241630Z - 251200Z



...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF

COASTAL CALIFORNIA AND PORTIONS OF THE CENTRAL VALLEY...



...SUMMARY...

An isolated risk for severe/damaging gusts and perhaps a brief

tornado will exist today into tonight along much of the California

Coast and portions of the Central Valley.



...California...

A shallow band of pre-frontal convection may continue to pose a

threat for locally severe/damaging winds (especially across higher

terrain/ridgetops) and perhaps a brief tornado this morning across

parts of coastal southern CA. This activity is being supported by

strong low-level warm advection and large-scale ascent associated

with an enhanced mid/upper-level jet. Current expectations are for

this activity to continue moving eastward through the afternoon

across the remainder of coastal southern CA in a strongly sheared

environment. However, various NAM/RAP forecast soundings across this

area suggest that even with low 60s surface dewpoints and

modest/filtered daytime heating, the overall severe threat will

likely remain isolated due to poor lapse rates aloft and limited

boundary-layer instability. Reference Mesoscale Discussion 2269 for

more details on the near-term severe threat across southern CA.



Additional rounds of convection are expected later this evening and

overnight into early Thursday morning over portions of

northern/central CA, as multiple mid-level shortwave troughs

embedded within persistent large-scale upper troughing over the

eastern Pacific overspread these areas. One such shortwave trough is

forecast to advance over coastal central CA and vicinity around

25/00-06Z this evening, with cool temperatures aloft (less than -20C

at 500 mb) supporting weak MUCAPE. Both low-level and deep-layer

shear are expected to gradually increase this evening as the

shortwave trough approaches, with some updraft organization

possible. Strong to locally severe winds and a brief tornado or two

appear possible with this activity, but uncertainty is still

substantial whether sufficient instability will be present to

support surface-based thunderstorms.



A stronger mid-level shortwave trough will move east-northeastward

from the eastern Pacific and approach the northern CA Coast by 12Z

Thursday morning, along with a deepening surface low and attendant

cold front. A 70-80+ kt mid-level jet will accompany this shortwave

trough, along with a 50-60 kt south-southwesterly low-level jet. A

broken band of low-topped thunderstorms will likely develop in

association with this shortwave trough along/ahead of the front, and

overspread coastal portions of northern/central CA late tonight

through early Thursday morning (25/06-12Z). A strongly sheared

environment and weak but sufficient MLCAPE may exist to support at

least an isolated threat for severe/damaging winds and a tornado or

two as this activity spreads inland through the end of the period.

Still, the overall severe threat should be tempered by the lack of

stronger instability.



Finally, some chance for low-topped/mini supercells may exist late

this afternoon/evening across parts of the Central Valley of CA. If

these thunderstorms can develop and be sustained, they could pose a

threat for both damaging winds and a brief tornado. But, confidence

in this scenario occurring remains rather low.



..Gleason/Bunting.. 12/24/2025



$$






                

                        

861

ACUS02 KWNS 241730

SWODY2

SPC AC 241728



Day 2 Convective Outlook

NWS Storm Prediction Center Norman OK

1128 AM CST Wed Dec 24 2025



Valid 251200Z - 261200Z



...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF

THE CENTRAL CALIFORNIA COAST...



...SUMMARY...

Thunderstorms with potential to produce marginally severe wind gusts

and perhaps a brief tornado will be possible on Thursday along parts

of the central California Coast.



...Central California Coast...

A broad upper low with multiple embedded disturbances will continue

to linger over the West Coast Thursday. Ahead of the trough, a

stream of moisture associated with an ongoing atmospheric river will

continue overspreading much of California where numerous convective

showers and isolated thunderstorms are expected to develop during

the day and continuing into early Friday. Buoyancy will be weak, but

MUCAPE peaking around 400 J/kg amidst the strong westerly flow could

support a couple marginally severe storms.



One of the more intense embedded features will likely move onshore

across parts of central CA early in the period before lifting

northward across southern WA Thursday evening. A strong offshore low

and cold front will likely support a broken band of low-topped

storms moving onshore early. Beneath a 50 to 60 knot southwesterly

low-level jet, flow aloft may mix down to the surface supporting

marginally severe gusts. Additionally, moderate shear in the lowest

few km could support a brief tornado with any transiently organized

storms.



A second embedded impulse is forecast to approach the coast farther

south into early Friday. Ascent ahead of the trough and a second

weaker cold front will help support another band of low-topped

storms. Considerable uncertainty remains regarding buoyancy for this

round given the overnight timing and multiple rounds of rain prior.

Still, some CAM guidance shows a narrow frontal band of low-topped

storms capable of damaging gusts or a brief tornado moving onshore

over the central Coast before 12z Friday.



..Lyons.. 12/24/2025



$$






                

                        

749

NWUS53 KAPX 240446

LSRAPX



Preliminary Local Storm Report

National Weather Service Gaylord MI

1146 PM EST Tue Dec 23 2025



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

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

            ..REMARKS..



1050 PM     Non-Tstm Wnd Gst 4 NNW Presque Isle      45.36N 83.49W

12/23/2025  M46 MPH          LHZ347             MI   Buoy



            Station PRIM4 - Presque Isle Light, MI.





&&



$$












                

                        

526

FXUS63 KAPX 241051

AFDAPX



Area Forecast Discussion

National Weather Service Gaylord MI

551 AM EST Wed Dec 24 2025



.KEY MESSAGES...



-Surface high pressure continues (relatively) mild temperatures and

quiet weather through Christmas.



-Low level trough digs across Michigan this Friday, delivering a

 quick shot of mixed precipitation. Cold temperatures across

 eastern upper today.



-Larger deepening cyclone continues widespread precip, gusty

 winds and lake effect snowfall chances around the Sunday/Monday

 timeframe.



&&



.SHORT TERM /THROUGH TONIGHT/...

Issued at 204 AM EST Wed Dec 24 2025



Pattern Synopsis...Mid-tropospheric ridging pattern across the

central U.S extends north today centering its axis over the plains

region. At the surface, anticyclonic flow with high pressure remains

straddled over the Great Lakes region continuing mild temperatures

(mild for late December) and overall quiet condtions.



Forecast Details...



Today...Overnight arctic air mass will spill cold temperatures from

Ontario into eastern upper this morning. Temperatures will struggle

to climb this morning with persistent low level clouds blocking

solar radiation from hitting the surface and light northerly flow

will continue cold air advection from the north. Temperatures across

eastern upper will likely remain in the single digits until roughly

the 18Z hour when anticyclonic flow backs wind direction to the SW.

Otherwise, the remainder of the CWA and expect more widespread mild

temperatures with highs in the low to mid 30s.



Tonight...As weak cold frontal boundary tracks across the CWA this

evening causing light winds to veer northwest tonight. Breezy winds

build tonight as support enough cold air advection to drop overnight

lows to the mid teen across eastern upper while northern lower

remains in the 20s. Atmospherically dry weather continues no chances

of precipitation across the CWA through the remainder of the short

term.



&&



.LONG TERM /THURSDAY THROUGH TUESDAY/...

Issued at 204 AM EST Wed Dec 24 2025



Christmas and Friday...Midlevel ridge axis centers itself over the

upper midwest this Thursday. Surface high pressure extended across

the region will keep conditions quiet and dry through Christmas.

Active weather returns overnight Christmas night through Friday

afternoon as an embedded height disturbance with a small vorticity

maxima progresses across Michigan. With H8 temperatures near

freezing, mixed precipitation will be the main concern with this

forecast. Current guidance continues to keep the boundary of mostly

mixed precipitation including freeing rain across central Michigan

extending up through M-72 while profiles north of the Bridge remain

cold enough to remain snow. Highest probs of ice accumulations of

only a trace to a few hundredths while accumulations of 2-4" remain

likely across eastern upper.



Saturday through Tuesday Outlook...Upper level pattern turns more

active this weekend as midlevel troughing currently over the Gulf of

Alaska progresses southeast this week and positions itself over the

upper midwest this Friday. Surface level cyclone will be deepening

and becoming more organized while tracking across the Great Lakes

region. Rainfall amounts remain questionable on if the frontal

boundary organizes, but cool northwest flow behind the front will

likely return classic accumulating lake effect snowfall through the

end of the forecast period.



&&



.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...

Issued at 551 AM EST Wed Dec 24 2025



Ongoing MVFR CIGs set to gradually erode to VFR through the

morning into this afternoon. Lighter S to SE flow prevails this

afternoon, tapering into the evening. Low clouds build back

through this evening into tonight, with most sites reverting

back to at least MVFR to close out the forecast period.



&&



.APX WATCHES/WARNINGS/ADVISORIES...

MI...None.

MARINE...None.



&&



$$



SHORT TERM...SJC

LONG TERM...SJC

AVIATION...HAD






                

                        

849

ACUS11 KWNS 241522

SWOMCD

SPC MCD 241522

CAZ000-241715-



Mesoscale Discussion 2269

NWS Storm Prediction Center Norman OK

0922 AM CST Wed Dec 24 2025



Areas affected...Portions of the southern California Coast



Concerning...Severe potential...Watch unlikely



Valid 241522Z - 241715Z



Probability of Watch Issuance...5 percent



SUMMARY...A brief tornado is possible along the immediate coast as a

shallow convective band moves east this morning.



DISCUSSION...A shallow band of convection, not currently deep enough

to support lightning production, continues to move eastward into the

LA Basin region ahead of a strong shortwave trough. The strongest

parts of this band remain near the coastline where dewpoints appear

to be in the low 60s F. Prior to the passage of this activity, KVTX

VAD data did show notable low-level shear/SRH. Recent velocity

imagery has also depicted weak, transient areas of low-level

rotation. A brief tornado will remain possible as this activity

continues east. Strong and gusty winds may also accompany the band.

The primary threat area will likely remain along the immediate coast

given decreasing surface moisture and buoyancy inland.



..Wendt/Gleason.. 12/24/2025



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



ATTN...WFO...SGX...LOX...



LAT...LON   33911889 34031895 34311890 34181855 33971821 33781789

            33581766 33461763 33411778 33461806 33551816 33911889



MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH