754
ACUS48 KWNS 132006
SWOD48
SPC AC 132004
DAY 4-8 CONVECTIVE OUTLOOK AMEND 1
NWS STORM PREDICTION CENTER NORMAN OK
0304 PM CDT FRI MAR 13 2026
VALID 161200Z - 211200Z
AMENDED TO EXPAND D4/MONDAY THREAT AREAS
..DISCUSSION
..UPDATED DISCUSSION FOR D4
THE MAJORITY OF DETERMINISTIC AND ENSEMBLE MODEL GUIDANCE AGREE ON A
DEEP MIDLEVEL TROUGH AND ASSOCIATED COLD FRONT THAT WILL MOVE
EASTWARD ACROSS THE APPALACHIANS AND TO THE ATLANTIC COAST BY
TUESDAY MORNING. SEVERE STORMS COULD BE ONGOING AT THE BEGINNING OF
THE PERIOD ALONG THE NORTHEAST GULF COAST INTO GA. THE WARM SECTOR,
CHARACTERIZED BY BOUNDARY-LAYER DEWPOINTS IN THE 60S, WILL EXPAND
NORTHWARD (GENERALLY EAST OF THE APPALACHIANS) THROUGH THE DAY AS
FAR NORTH AS PA. THOUGH CLOUDS COULD LIMIT DOWNSTREAM SURFACE
HEATING SOMEWHAT, VERY STRONG WIND PROFILES AND FOCUSED FORCING FOR
ASCENT WILL FAVOR A CONTINUATION OF CONVECTION ALONG THE FRONT, AS
WELL AS PRE-FRONTAL CONVECTION, WITH THE POTENTIAL TO PRODUCE
RELATIVELY WIDESPREAD DAMAGING WINDS AND SEVERAL TORNADOES.
..PREVIOUS DISCUSSION BELOW
SIGNIFICANT SEVERE WINDS AND THE POTENTIAL FOR A FEW TORNADOES WILL
DEVELOP ON MONDAY OVER PARTS OF THE CAROLINAS AND MID ATLANTIC.
MODELS ARE IN GOOD AGREEMENT WITH THE LARGE SCALE PATTERN ON
MONDAY/D4, DEPICTING A DEEP UPPER TROUGH MOVING OUT OF THE
MISSISSIPPI VALLEY AND EJECTING IN NEGATIVE-TILT FASHION ACROSS THE
MID ATLANTIC AND INTO TO THE NORTHEAST.
GIVEN THE ANTECEDENT UPPER RIDGING ON THE PREVIOUS DAY, LOW-LEVEL
SOUTHERLY WINDS WILL HELP TO MOISTEN THE AIR MASS WELL AHEAD OF AN
APPROACHING COLD FRONT. BY 12Z MONDAY, 60S F DEWPOINTS WILL ALREADY
EXTEND FROM NORTHERN GA ACROSS THE PIEDMONT AND INTO SOUTHEAST VA,
AND THIS PLUME OF MOISTURE WILL RAPIDLY SPREAD NORTH WITH NEAR 60 F
DEWPOINTS INTO SOUTHEAST PA BY 00Z.
THERE APPEARS TO BE TWO REGIMES FOR SEVERE POTENTIAL ON MONDAY.
FIRST, UP TO 1000 J/KG MUCAPE MAY DEVELOP WELL AHEAD OF THE
APPROACHING COLD FRONT, AND THERE IS SOME INDICATION THAT SCATTERED
CONVECTION MAY OCCUR ACROSS THE WARM SECTOR FROM MID TO LATE
AFTERNOON. IF THIS OCCURS, SUPERCELLS WOULD BE MOST LIKELY, WITH
POTENTIAL FOR A FEW TORNADOES FROM THE CAROLINAS INTO EASTERN VA.
MODELS ALSO INDICATE AN ELONGATED PRESSURE FALL/RISE COUPLET, WHICH
WHEN COMBINED WITH 50-70 KT 850 MB WINDS AND EXTREME LOW-LEVEL
SHEAR, COULD EASILY RESULT IN A QLCS ALONG THE COLD FRONT WITH
CORRIDORS OF SIGNIFICANT DAMAGING WINDS AND EMBEDDED TORNADO RISK.
BEYOND MONDAY/D4, STABLE AIR BEHIND THIS SYSTEM WILL LIKELY PRECLUDE
ANY SEVERE THREAT THROUGH FRIDAY/D8.
..THOMPSON.. 03/13/2026
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