651
ACUS01 KWNS 180049
SWODY1
SPC AC 180047

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0747 PM CDT Thu Jul 17 2025

Valid 180100Z - 181200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN EASTERN MT TO
FAR SOUTHWEST ND...

...SUMMARY...
A couple supercells will remain capable of large hail and severe
gusts through about midnight across eastern Montana.

...Northern Great Plains...
A couple supercells are ongoing over north-central MT with a history
of measured severe gusts and severe hail signatures per MRMS MESH.
This activity should persist southeastward through at least late
evening amid strong effective bulk shear but weak buoyancy and
modest mid-level lapse rates per the 00Z GGW sounding. Most guidance
outside of the RRFS suggest that convection will remain as discrete
supercells before eventually waning as it impinges on minimal
surface-based instability near the MT/ND border. With such a cool
and dry boundary layer per surface observations across far eastern
MT into ND, the overall severe threat should diminish towards
midnight. Elevated convection should develop across parts of the
Dakotas overnight, with weak MUCAPE marginalizing severe potential.

...Southern High Plains...
A slow-moving, loosely organized cluster is ongoing east-southeast
of the Sangre de Cristo Mountains in northeast NM. While the
boundary layer is climatologically cool, it is moist and moderately
unstable (per the 00Z AMA sounding), amid persistent low-level
easterlies. This upslope flow regime should support cluster
maintenance through late evening before gradually waning overnight.
While heavy rain is the primary hazard (per WPC ERO SLGT risk), a
few strong to marginal severe gusts and small hail remain possible.

...Northern ME...
Convection has largely waned across New England and should continue
to do so over the next hour. With some lingering deep convection
across northern ME, a moist boundary layer and still sufficient
deep-layer shear (per the CBW VWP) may support a weakly rotating
storm or two before convection spreads entirely into NB.

...Eastern OK to the Delmarva...
A couple microbursts capable of strong gusts may still occur in yet
to be overturned areas across a broad swath from the Ozarks to the
Mid-Atlantic Coast. With modest deep-layer shear and nocturnal
boundary-layer cooling, severe probabilities appear negligible.

..Grams.. 07/18/2025

$$