189
ACUS03 KWNS 150729
SWODY3
SPC AC 150729

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0229 AM CDT Thu May 15 2025

Valid 171200Z - 181200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SATURDAY ACROSS
PARTS OF EASTERN NORTH CAROLINA...EASTERN VIRGINIA...CENTRAL AND
EASTERN MARYLAND...DELAWARE...SOUTHEASTERN PENNSYLVANIA...CENTRAL
AND SOUTHERN NEW JERSEY AND LATE SATURDAY INTO SATURDAY NIGHT ACROSS
PARTS OF WEST CENTRAL THROUGH NORTH CENTRAL TEXAS...EASTERN OKLAHOMA
AND SOUTHWESTERN INTO CENTRAL ARKANSAS...

...SUMMARY...
Severe thunderstorms are possible Saturday across parts of the Mid
Atlantic, and late Saturday into Saturday night across parts of the
southeastern Great Plains.

...Discussion...
Downstream of a persistent, prominent mid-level ridge across the
southern mid-latitude and subtropical eastern Pacific, models
indicate that large-scale troughing will continue to dig inland of
the Pacific coast through this period.  It appears that this will
include one notable embedded smaller-scale perturbation digging
across the Sierra Nevada, toward the Four Corners, and a trailing
perturbation digging across the Pacific Northwest coast.

Farther downstream, it appears that one or two  more modest short
wave impulses, within a belt of westerlies emanating from the
subtropical eastern Pacific, may accelerate across the northern
Mexican Plateau through the southern Great Plains and lower
Mississippi Valley, around the northwestern periphery of broad
mid/upper ridging centered over the Gulf Basin.  To the north of
this ridge, large-scale ridging within the mid-latitude westerlies
is forecast to overspread much of the interior U.S., with a remnant
downstream cyclone and associated troughing progressing across parts
of the Northeast and Mid Atlantic.

In lower levels, models generally indicate that a significant cold
front will advance southeast of the lower Great Lakes and Ohio
Valley, while stalling across parts of the Mid South into central
Great Plains.  However, this is likely to be preceded by a weaker
front, largely driven or reinforced by outflow from Friday/Friday
night convection.

...Mid Atlantic...
Strong convectively augmented westerly lower/mid-tropospheric flow
(in excess of 50 kt in the 850-700 mb layer) is likely to spread
east of the Allegheny and Blue Ridge Mountains, coincident with the
convective outflow boundary by early Saturday.  The extent and
intensity of continuing convective development along the gust front
at the outset of the period remains unclear.  However, if the severe
storm cluster from Friday night does not maintain strength with a
continuing risk for severe wind gusts into and across the Mid
Atlantic early Saturday, it is possible that destabilization ahead
of the surface boundary could become sufficient for considerable
re-intensification of thunderstorm activity along it, before it
advances offshore.

...Southeastern Great Plains...
Beneath steep lower/mid-tropospheric lapse rates, models indicate
that seasonably moist air will maintain a reservoir of large CAPE
along and south of the initial pre-frontal wind shift/convective
outflow, roughly across the Ark-La-Texas, and east of a sharpening
dryline, across western North Texas toward the Del Rio TX area by
late afternoon.  Aided by forcing for ascent and strengthening
westerly mid/upper flow associated with the subtropical
perturbations, isolated to scattered supercells may initiate and
propagate off the retreating dryline by late afternoon.  Other
strong to severe thunderstorm development is possible, aided by
forcing for ascent associated with warm advection, where mid-level
inhibition will be weaker along and north of the initial pre-frontal
wind shift, and perhaps near the surface front across northern
Oklahoma into north central Arkansas.

..Kerr.. 05/15/2025

$$