ACUS01 KWNS 031214

SWODY1

SPC AC 031213



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

0713 AM CDT Thu Jul 03 2025



Valid 031300Z - 041200Z



...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR NORTH DAKOTA

AND MUCH OF THE NORTHEAST...



...SUMMARY...

Scattered severe thunderstorms capable of producing severe/damaging

winds and large hail are forecast across parts of the Northeast and

northern Plains today.



...Northern Plains...

Water-vapor imagery this morning indicates a weak disturbance over

western ND is cresting a central U.S. upper ridge.  An upstream

minor perturbation is forecast to move from northern WY/MT eastward

into western ND by late afternoon/evening.  Coincident with this

feature, an elongated weak low is forecast from the north-central

High Plains northward into SK, with an attendant warm frontal zone

draped east-southeast from ND into the Upper Midwest.  



A seasonably moist boundary layer is indicated by morning surface

observations.  Dewpoints currently range from the lower 60s deg F

over ND to upper 60s to near 70 in central and eastern SD.  Steep

700-500 mb lapse rates coupled with heating in wake of morning cloud

debris/shower activity, will likely result in a weakly capped and

very unstable airmass by mid-late afternoon over ND where low-level

moisture is maximized.  Isolated to scattered storms are forecast to

develop 20-23 UTC with a few supercells possible.  A risk for very

large hail and perhaps a tornado would accompany the supercells

before storm outflow and mergers leading to upscale growth into one

or two eastward-moving clusters during the evening.  Have introduced

a significant wind highlight for potential peak gusts in the 70-85

mph range.  A focused mesoscale wind corridor is indicated by some

00z HREF and MPAS members but sufficient model variability precludes

higher probabilities at this time.  This activity will likely weaken

late this evening as it approaches the Red River and adjacent

portions of northern MN. 



...Northeast...

An upper trough with an embedded 40-50 kt mid-level speed maximum

will pivot across the Northeast today. A related surface cold front

will likewise develop eastward across this region through the

afternoon/evening.  Heating will act to destabilize a moist

airmass and support weak to moderate buoyancy (500-1500 J/kg MLCAPE)

along/ahead of the cold front by early afternoon.  Sufficient

deep-layer shear will favor multicellular and some transient

supercell organization.  Scattered damaging (50-65 mph) winds should

be the primary severe threat as low-level lapse rates gradually

steepen. But, some large hail may occur given favorable shear,

especially with any supercell.  The severe risk will likely diminish

by the early to mid evening as thunderstorms push east of the coast.



...Upper Midwest...

Weak forcing aloft and the persistence of the upper ridge should

tend to limit convective development in an otherwise moderately to

strongly unstable airmass. Still, any thunderstorms which can

develop, perhaps aided by modest low-level warm advection this

evening/tonight, could pose an isolated severe hail/wind threat.



..Smith/Broyles.. 07/03/2025



$$