SPC - No watches are valid as of Tue Jan 20 12:52:01 UTC 2026

No watches are valid as of Tue Jan 20 12:52:01 UTC 2026.

SPC MD 30

MD 0030 CONCERNING HEAVY SNOW FOR EASTERN SHORE OF LAKE ONTARIO INTO THE TUG HILL PLATEAU

Mesoscale Discussion 0030
NWS Storm Prediction Center Norman OK
0522 AM CST Tue Jan 20 2026

Areas affected...Eastern shore of Lake Ontario into the Tug Hill
Plateau

Concerning...Heavy snow 

Valid 201122Z - 201615Z

SUMMARY...A heavy lake-effect snow band will continue through the
morning, with rates of 2-4 inches/hour possible in the most intense
portions of the band.

DISCUSSION...A well-established lake-effect snow band is ongoing
from Lake Ontario into parts of the Tug Hill Plateau this morning.
While some north-south oscillations will be possible as a minor
midlevel shortwave trough approaches from the west, this band is
expected to persist through the morning. A favorably long fetch off
of Lake Ontario and a relatively deep convective boundary layer will
continue to favor very heavy snow rates within the most intense
portions of the band. 

Short-term guidance indicates that midlevel temperatures will reach
a minimum (-32 to -33 C at 700 mb) by mid/late morning, and snow
rates of 2-4 inches/hour will continue to be possible through this
time frame. Some warming aloft and modest lowering of equilibrium
levels is eventually expected in the wake of the approaching
shortwave trough, but the favorable fetch will help to maintain this
band through much of the day.

..Dean.. 01/20/2026

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

ATTN...WFO...ALY...BGM...BUF...

LAT...LON   43977635 44047581 44027529 43777512 43597509 43477539
            43437602 43467629 43547644 43977635 

SPC Jan 20, 2026 1300 UTC Day 1 Convective Outlook

SPC 1300Z Day 1 Outlook
      
Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0648 AM CST Tue Jan 20 2026

Valid 201300Z - 211200Z

...NO THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Thunderstorms are not forecast across the U.S. today or tonight.

...Synopsis and Discussion...
With large-scale upper troughing persisting over central/eastern
Canada and the CONUS today, expansive surface high pressure in place
across the MS/OH Valleys and eastern states will shift gradually
eastward as weak surface lee troughing/low development occurs across
the central High Plains. Modest low-level moisture will advance
slightly inland across parts of deep south into coastal/east TX, but
instability is expected to remain too limited to support
thunderstorms through the end of the period.

..Gleason/Dean.. 01/20/2026


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SPC Jan 20, 2026 Day 4-8 Severe Weather Outlook

Day 4-8 Outlook
      
Day 4-8 Convective Outlook  
NWS Storm Prediction Center Norman OK
0252 AM CST Tue Jan 20 2026

Valid 231200Z - 281200Z

...DISCUSSION...
An arctic airmass will settle across much of the CONUS east of the
Rockies on Days 4-5/Fri-Sat. Resulting strong high pressure and
cold/dry/stable conditions will persist over much of the country
throughout the period. However, some thunderstorm potential could
develop across portions of the Gulf Coast states/Southeast on Days
4-6/Fri-Sun as a surface cold front progresses east/southeast.
Modified Gulf moisture will be in place near the immediate Gulf
Coast. Warm advection in the low-levels could result in isolated
thunderstorms near or just to the cool side of the cold front Friday
afternoon across parts of TX, spreading east/northeast across the
Southeast through Saturday and early Sunday. Instability should
remain weak as better moisture remains offshore, and due to
convection becoming undercut by the cold front.


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