565
ACUS48 KWNS 090929
SWOD48
SPC AC 090927

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0327 AM CST Tue Dec 09 2025

Valid 121200Z - 171200Z

...DISCUSSION...
Medium-range models indicate that at least a couple of short wave
troughs, digging within an initially strong northwesterly regime
across and to the east-southeast of the Canadian Rockies, will
contribute to reinforcement of large-scale troughing farther
downstream late this work week into next weekend.  As this occurs,
cold surface ridging building to the lee of the Canadian and
northern U.S. Rockies is forecast to eventually overspread much of
the central and eastern U.S., offshore Atlantic and northwestern
Gulf Basin by the beginning of next week.

Based on the past few model runs, it appears that an initial
southeastward surge of cold air may weaken before reaching the Gulf
coast, allowing for a gradual boundary-layer modification over the
northwestern Gulf Basin to continue, before the more substantive
surge of cold air reaches the northern Gulf by late this weekend.
Particularly in association with the stronger front, if not also the
weaker initial one, a moistening elevated and perhaps boundary-layer
based return flow may contribute to sufficient destabilization to
support a risk for thunderstorms, anywhere in a corridor from
southeastern Texas toward the Mid South and Tennessee Valley.
However, with any surface frontal wave development forecast to
remain weak, the risk for severe weather is likely to remain low.

Into early next week, model output becomes more varied, but it
appears that flow may trend more zonal across the northern
mid-latitudes of North America.  In lower latitudes, another
developing moist southerly return flow, in advance of troughing
digging across the southern Rockies and Great Plains, may contribute
to renewed thunderstorm development across the northwestern Gulf
coast vicinity.  However, the potential for severe weather still
seems limited at this time.

..Kerr.. 12/09/2025