ACUS48 KWNS 130859
SWOD48
SPC AC 130858

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0258 AM CST Mon Jan 13 2025

Valid 161200Z - 211200Z

...DISCUSSION...
Shortwave upper ridging will move over the southern Plains vicinity
on Day 4/Thu as shortwave trough develops eastward over the
Southwest. While surface lee troughing will develop over the High
Plains as this occurs, high pressure will persist across eastern
portions of the Plains into the Southeast. This will keep Gulf
moisture offshore and thunderstorm potential is low on Day 4/Thu.

Forecast guidance continues to have quite a bit of spread heading
into the weekend (Days 5-6/Fri-Sat). In general, the Southwest upper
trough is expected migrate eastward into the southern Plains on
Friday, and across the Mid-South and Southeast on Saturday. However,
forecast guidance shows a fairly low-amplitude trough despite strong
mid/upper southwesterly flow streaming over the Plains into the
Southeast. A surface low should develop over the southern High
Plains and migrate east through weekend, allowing for northward
transport of Gulf moisture from east TX into the Lower MS Valley and
central/eastern Gulf coast vicinity. Guidance varies quite a bit in
the northward extent of moisture return. The ECMWF suite of guidance
is a bit faster and further north compared to the GFS model suite.
Furthermore, SPC and NSSL machine learning guidance has trended
lower with severe potential compared to yesterday. While some severe
potential is possible from east TX into the central Gulf coast
Friday evening into Saturday, confidence remains too low to
delineate unconditional Slight risk probabilities at this time.

By Day 7/Sun, a cold front will move offshore the Atlantic coast and
deep into the Gulf of Mexico. Strong surface high pressure and an
arctic airmass will overspread much of the CONUS, bringing very
cold, dry/stable conditions into early next week.

..Leitman.. 01/13/2025

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