####018002707####
ACUS48 KWNS 120900

SWOD48

SPC AC 120859



Day 4-8 Convective Outlook  

NWS Storm Prediction Center Norman OK

0359 AM CDT Fri Apr 12 2024



Valid 151200Z - 201200Z



...DISCUSSION...

...Significant severe weather possible late afternoon Monday through

Tuesday evening across the central states...



Latest ensemble and deterministic guidance continues an overall

slower trend with the evolution of an amplifying shortwave trough

expected to be over parts of the Southwest early Monday. As it

crosses the southern Rockies into the central Great Plains by midday

Tuesday, the tropospheric flow field will amplify Monday night

through Tuesday morning. Substantial lee cyclogenesis will occur

over the central High Plains by Monday afternoon, and this cyclone

should track into the Mid-MO Valley vicinity by Tuesday afternoon

before occluding over the Upper MS Valley late Tuesday. This overall

slower trend results in expansion of severe probabilities

west-southwestward on D5.



Low-level moisture modification from the northwest Gulf, while

sufficient for severe storms, does not appear to be overly rich. As

such, the more westward initiation of convection during the late

afternoon to early evening Monday may be within a more deeply mixed

environment across parts of the dryline. Still, there is consensus

that a plume of low to mid 60s surface dew points should be advected

ahead of the dryline across much of western OK into western north

TX. More widespread convective development will occur during the

evening to overnight time frame, especially as the Pacific cold

front overtakes the dryline and surges east from parts of KS

southward. With this coinciding with the period of tropospheric flow

amplification, it is plausible an extensive convective band is

maintained east-northeast into early Tuesday. Whether this outpaces

the relatively confined warm-moist sector and weakens, or is

maintained through the end of D4 is unclear. This will have profound

implications on the degree of daytime destabilization downstream

over parts of the Corn Belt to the south-central states. With slower

timing, and if convection can adequately weaken, a conditionally

more favorable tornado threat may occur on Tuesday over the Mid-MS

Valley vicinity. Otherwise, should convection continue

east-northeast, greater buoyancy may largely be confined south

across the Ark-La-Tex into the Mid-South. As such, will defer to

later outlooks for a potential 30 percent area on D5-Tuesday.



Severe probabilities appear too low in D6-8 to warrant consideration

of highlights as predictability wanes.



..Grams.. 04/12/2024