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ACUS01 KWNS 301630

SWODY1

SPC AC 301629



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

1129 AM CDT Tue Apr 30 2024



Valid 301630Z - 011200Z



...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON

AND EVENING ACROSS PARTS OF WESTERN IOWA...SOUTHEAST

NEBRASKA...NORTHEAST KANSAS...AND NORTHWEST MISSOURI...



...SUMMARY...

The greatest threat for severe weather (large hail, severe gusts,

and a few tornadoes) is from western and central Iowa to

northeastern Kansas.



...Eastern NE/Western IA/Northwest MO/Northeast KS...

Water vapor loops show a fast-moving shortwave trough and associated

mid/upper level speed max moving across the central Rockies into the

Plains.  Ahead of this trough, southerly low-level winds are

transporting moisture northward with dewpoints in the 60s now as far

north as southeast NE.  Continued daytime heating and moisture

advection will lead to a narrow corridor of moderate CAPE over

eastern NE by mid-afternoon.  A consensus of morning model guidance

indicated that thunderstorms will form in this regime, with other

intense storms developing southward along the surface cold front

into northeast KS by late afternoon.  Forecast soundings show shear

profiles favorable for supercell structures capable of very large

hail and a few tornadoes.  After dark, these storms are expected to

congeal into one or more bowing structures that will track eastward

into central IA/northern MO with a greater risk of damaging wind

gusts along with hail and perhaps tornadoes.



...Eastern KS/Western OK/Northwest TX...

The surface dryline will extend southward from northeast KS into

northwest OK and northwest TX.  Isolated intense storms are expected

from roughly Wichita northward, with decreasing confidence from

there southward.  Weak large scale forcing, rising mid level

heights, and generally warming temperatures at 700mb suggest any

storms that form along the dryline will be widely scattered. 

However, large CAPE values, steep mid level lapse rates, and

sufficient vertical shear will support supercell structures capable

of all severe hazards in any storm that can form/sustain.  Will

maintain the ongoing SLGT/MRGL areas at this time, but will

reevaluate at 20z.



...NY/PA...

Strong daytime heating is occurring over areas from central NY into

central PA, where dewpoints are in the upper 50s.  Forecast

soundings suggest afternoon MLCAPE values of 500-1000 J/kg, leading

to scattered afternoon thunderstorms.  Low-level winds are

relatively weak/veered, but sufficient winds aloft and steep

low-level lapse rates could contribute to a risk of gusty/damaging

wind gusts and hail in the strongest cells this afternoon.



..Hart/Lyons.. 04/30/2024



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