SPC Feb 27, 2025 1300 UTC Day 1 Convective Outlook

SPC 1300Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0702 AM CST Thu Feb 27 2025

Valid 271300Z - 281200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Isolated to scattered thunderstorms are possible from the Mid and
Upper Ohio Valley to the Carolinas/southern Virginia.

...Synopsis...
Recent satellite imagery shows a pair of shortwave troughs moving
through the broadly cyclonic flow aloft extending from the
northern/central Plains and southern Canadian Prairies into the OH
Valley and Northeast. The lead wave in the pair is currently over
the Upper OH Valley, and should continue northeastward through the
Northeast States today. The trailing wave is currently moving
southeastward through the Upper Midwest, with the expectation that
it will pivot more eastward as it moves through the Upper Great
Lakes and OH Valley today before then continuing eastward through
the Mid-Atlantic States overnight.

Recent surface analysis placed a low over eastern Lake Erie, with an
extensive cold front extending southwestward from this low into the
TX Hill Country. This low is forecast to progress northeastward up
the St. Lawrence Valley just ahead of the lead shortwave, with the
attendant front moving eastward/southeastward. A weak, secondary
frontal boundary is expected to move through the OH Valley,
demarcated primarily by a shift to stronger, more northwesterly
winds. Isolated thunderstorms are possible along both of these
fronts, mostly during the late afternoon and early evening.

...Mid/Upper OH Valley...
Very cold mid-level temperatures are expected to spread across the
region as the shortwave trough mentioned in the synopsis progresses
through. These cold temperatures and associated steep mid-level
lapse rates will occur atop a well-mixed boundary layer, resulting
in 7 to 8 deg C/km lapse rates throughout the troposphere. These
lapse rates will help support modest buoyancy, despite surface
temperatures in the upper 40s/low 50s and dewpoints in the upper
30s. Isolated thunderstorm development is anticipated along the
surface boundary that is expected to move through the region, with
the greatest coverage in the OH/KY/WV border vicinity this evening.
Predominantly low-topped thunderstorms with transient updraft
structures are anticipated. Even so, gusty winds and small hail may
be noted with the more persistent and organized updrafts. Overall
severe coverage is expected to be below thresholds for outlooking
any areas.

...Carolinas in central GA...
Modest pre-frontal buoyancy is expected to develop amid increasing
mid-level moisture and diurnal heating, supporting the potential for
isolated thunderstorms as the front moves through. Small hail and a
damaging gust or two are possible within the strongest storms, but a
largely anafrontal and elevated storm structure should keep the
overall severe potential low.

..Mosier/Grams.. 02/27/2025

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