Severe Storm Outlook Narrative (AC)
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000
ACUS48 KWNS 100900
SWOD48
SPC AC 100859

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0359 AM CDT Wed Apr 10 2024

Valid 131200Z - 181200Z

...DISCUSSION...
Primary feature of concern will be an amplified upper low that is
initially off the CA coast at 12Z Saturday. This low should dampen
as it steadily progresses across the Southwest, before amplifying
once again as it emerges onto the central Great Plains sometime on
D6, as a separate shortwave trough digs towards the Pacific
Northwest. Timing spread within the 00Z deterministic and ensemble
guidance appears larger relative to yesterday, with the 00Z ECMWF
decidedly trending farther east over the past 24 hours. It appears
to be on the eastern envelope compared to its ensemble members. The
overall forecast impact is with regard to dryline placement and
surface cyclone evolution during the day on Monday and beyond.

The actual severe weather setup appears substantial. Air mass
modification will ensue northward from the western Gulf on D3, with
multiple days to improve the low-level moisture profile amid well
above-normal surface temperatures and a pronounced elevated mixed
layer. With the likely flow field amplification through the
troposphere, all ingredients appear present for a significant severe
weather day on D6/Monday. The areal uncertainty of the synoptic
features is the primary limiting factor. For now, have added a
confined 30 percent highlight to indicate the higher-end potential
and the most probable corridor, while broadening the previous 15
percent area.

A lesser severe threat will probably continue into D7/Tuesday. But
even further spatial uncertainty, in conjunction with the impact of
the prior day convection and consensus signal for the deep cyclone
to occlude northeastward, renders low confidence for highlighting a
severe threat area yet. The area-of-interest appears to have shifted
more to the east relative to yesterday, in an arc around the eastern
Corn Belt to the Ark-La-Tex.

..Grams.. 04/10/2024
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