500
ACUS02 KWNS 151727
SWODY2
SPC AC 151725
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1225 PM CDT THU OCT 15 2026
VALID 161200Z - 171200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE MID ATLANTIC INTO SOUTHERN NEW ENGLAND...
..SUMMARY
SCATTERED DAMAGING GUSTS AND PERHAPS A BRIEF TORNADO MAY ACCOMPANY A
SQUALL LINE THAT IS EXPECTED ACROSS THE MID-ATLANTIC INTO NEW
ENGLAND TOMORROW (FRIDAY).
..SYNOPSIS
A PRONOUNCED, POSITIVELY TILTED UPPER TROUGH WILL CONTINUE TO
AMPLIFY AS IT RAPIDLY APPROACHES THE EAST COAST TOMORROW (FRIDAY).
ACCOMPANYING THIS UPPER TROUGH WILL BE A STRONG SURFACE CYCLONE,
WHICH WILL TRACK FROM THE EASTERN GREAT LAKES TO NORTHERN NEW
ENGLAND DURING THE DAY. A MARGINALLY UNSTABLE AIRMASS WILL ADVECT
AHEAD OF A SURFACE TROUGH ATTENDANT FROM THE CYCLONE, SUPPORTING
DEEP-MOIST CONVECTIVE POTENTIAL AMID AN ENVIRONMENT CHARACTERIZED BY
STRONG FORCING AND VERTICAL WIND SHEAR. AS SUCH, SEVERE STORMS WILL
BE POSSIBLE ACROSS PORTIONS OF THE MID-ATLANTIC INTO SOUTHERN NEW
ENGLAND LATE TOMORROW MORNING INTO THE EVENING HOURS.
..MID-ATLANTIC INTO SOUTHERN NEW ENGLAND
AS THE UPPER TROUGH AMPLIFIES AND THE SURFACE CYCLONE DEEPENS OVER
THE NORTHERN APPALACHIANS, LOW-LEVEL CONVERGENCE ALONG THE ATTENDANT
SURFACE TROUGH WILL INCREASE INTO THE MORNING HOURS, RESULTING IN
THE DEVELOPMENT OF LOW-TOPPED CONVECTION THAT WILL QUICKLY EVOLVE
INTO A SQUALL LINE ACROSS WESTERN NY/PA. THE NORTHWARD ADVECTION OF
MID 60S F SURFACE DEWPOINTS BENEATH 6 C/KM MID-LEVEL LAPSE RATES
WILL RESULT IN 500 J/KG MLCAPE ON A WIDESPREAD BASIS AHEAD OF THE
LINE, WITH LOCALLY HIGHER VALUES APPROACHING 1000 J/KG IN SPOTS.
SOME GUIDANCE MEMBERS SUGGEST THAT SURFACE AIRMASS RECOVERY MAY BE
BRIEF AHEAD OF THE SQUALL LINE GIVEN THE POTENTIAL FOR WIDESPREAD
ANTECEDENT CLOUD COVER. STILL, STRONG TROPOSPHERIC WIND FIELDS WILL
ACCOMPANY THE SQUALL LINE, WITH FORECAST SOUNDINGS SHOWING 50+ KT
FLOW AS LOW AS 800-700 MB, WITH 35-40 KT FLOW CONTAINED WITHIN THE
BOUNDARY LAYER, JUST ABOVE THE SURFACE.
REGARDLESS OF THE DEGREE OF DESTABILIZATION THAT PRECEDES THE SQUALL
LINE, DOWNWARD MOMENTUM TRANSPORT OF THE STRONGER FLOW ALOFT WITHIN
THE SQUALL LINE SHOULD SUPPORT STRONG TO OCCASIONALLY SEVERE SURFACE
GUSTS, MOSTLY IN THE 35-55 KT RANGE. SCATTERED INSTANCES OF
TREE/WIRE DAMAGE ARE EXPECTED, STARTING FROM AROUND WESTERN PA
DURING THE LATE MORNING HOURS, TO THE EAST COAST AROUND EARLY
EVENING.
..SQUITIERI.. 10/15/2026
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