Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1229 AM CDT Thu Jul 25 2024

Valid 251200Z - 261200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND EVENING ACROSS PARTS OF THE EASTERN CAROLINAS AND ADJACENT
SOUTHEASTERN VIRGINIA...SOUTHEASTERN ARIZONA AND ADJACENT PORTIONS
OF SOUTHWESTERN NEW MEXICO...AND CENTRAL MONTANA...

...SUMMARY...
The risk for severe thunderstorms appears likely to remain
seasonably low across much of the U.S. today through tonight.

...Synopsis...
Stronger westerlies remain generally confined to the northern
mid-latitudes, with one significant short wave trough and embedded
low currently progressing inland of the British Columbia/Pacific
Northwest coast.  This perturbation is forecast to continue slowly
across and east-northeast of the Canadian/northern U.S. Rockies
today into early Friday, accompanied by cyclogenesis across the
northern Canadian Prairies (near the northern Alberta/Saskatchewan
border vicinity).  While ridging to its east and south is likely to
be maintained across the northern Great Plains/upper Mississippi
Valley into the Southwest, models indicate that it may undergo at
least some suppression, with the Southwestern mid-level high center
shifting across western Arizona toward northern Baja.  

Farther downstream, broad mid-level troughing is forecast to
continue slowly eastward across the Ohio Valley, Mid Atlantic and
Northeast, with the primary embedded short wave digging southeast of
the lower Great Lakes/St. Lawrence Valley, before turning across and
offshore of the New England coast.  Seasonably high precipitable
water content will generally remain confined to portions of the
northwestern Gulf coast into lower Mississippi Valley, the eastern
Gulf into south Atlantic Coast states, and near the Southwestern
international border area.

...Northern Rockies...
Near/just ahead of the base of the mid-level short wave trough,
scattered thunderstorm development is forecast to initiate off the
higher terrain, and in advance of a cold front, across central
Montana late this afternoon, where a hot and deeply mixed boundary
layer may become characterized by modest instability.  With forecast
soundings suggesting 40-60 degree F temperature-dew point spreads by
peak heating, a few strong downbursts are possible.  Downward mixing
of 30-40+ kt ambient southwesterly to westerly flow in the 700-500
mb layer may contribute to the potential development of localized
damaging wind gusts in consolidating outflows, as convection spreads
eastward into this evening.

...Arizona...
Perhaps aided by forcing associated with a perturbation progressing
around the periphery of the mid-level high, thunderstorms appear
likely to again initiate across the Mogollon Rim and adjacent
mountains of southwestern New Mexico this afternoon.  Given the
position and movement of the mid-level high, northeasterly steering
flow off the higher terrain toward the more strongly heated and
deeply mixed lower elevations appears likely to remain focused
across southeastern into adjacent portions of central Arizona,
possibly including portions of the Greater Phoenix area.

...Southern Mid Atlantic...
Near the southern periphery of the larger-scale mid-level troughing,
a belt of 30-40 kt south to southwesterly flow in the 850-500 mb
layer may enhance convective development today within a plume of
seasonably high moisture content across eastern North Carolina and
adjacent portions of northeastern South Carolina/southeastern
Virginia.  With moderate CAPE contributing to vigorous updrafts,
heavy precipitation loading and downward mixing of momentum may
contribute to a few strong downdrafts with potentially damaging
surface gusts.

..Kerr/Halbert/Lyons.. 07/25/2024