570
ACUS01 KWNS 181233
SWODY1
SPC AC 181232
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0732 AM CDT SAT APR 18 2026
VALID 181300Z - 191200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
UPPER OHIO VALLEY TO THE APPALACHIANS...
..SUMMARY
SCATTERED STRONG TO SEVERE THUNDERSTORMS CAPABLE MAINLY OF DAMAGING
WINDS WILL BE POSSIBLE TODAY ACROSS THE UPPER OHIO VALLEY AND
CENTRAL APPALACHIANS.
..SYNOPSIS
WATER-VAPOR IMAGERY THIS MORNING SHOWS A LARGE-SCALE UPPER TROUGH
OVER THE UPPER MIDWEST INTO THE SOUTH-CENTRAL PLAINS. AN ELONGATED
MID-LEVEL VORTICITY LOBE AND ASSOCIATED SPEED MAX WILL QUICKLY MOVE
EASTWARD ACROSS THE MIDWEST TODAY AND REACH THE LOWER GREAT LAKES
AND UPPER OH VALLEY LATE TONIGHT. FARTHER SOUTH, A BELT OF STRONG
WEST-SOUTHWESTERLY FLOW ASSOCIATED WITH A SUBTROPICAL JET WILL
RESIDE OVER TX.
A COLD FRONT EXTENDING FROM A LOW NEAR JAMES BAY SOUTHWARD THROUGH
THE GREAT LAKES AND INTO TX WILL CONTINUE TO PUSH EAST AND SOUTHEAST
THROUGH THE PERIOD. CONVECTIVE OUTFLOW OVER THE OH VALLEY TO THE
EAST OF THE FRONT WILL EVENTUALLY BE OVERTAKEN BY THE FRONT LATER
TODAY AS A BAND OF SHOWERS/THUNDERSTORMS DEVELOPS OVER THE UPPER OH
VALLEY BY EARLY AFTERNOON.
..OH VALLEY INTO THE APPALACHIANS
SOME HEATING COMBINED WITH A GRADUALLY MOISTENING AIRMASS (55-60 DEG
F SURFACE DEWPOINTS) WILL RESULT IN WEAK DESTABILIZATION BY MIDDAY
AS CONVECTIVE DEVELOPMENT ENSUES NEAR THE PRECEDING OUTFLOW/WIND
SHIFT AND FRONT. AMPLE MID TO HIGH-LEVEL FLOW WILL AID IN SOME
POTENTIAL FOR STORM ORGANIZATION, MAINLY IN THE FORM OF A FEW
STRONGER CELLS AND LINEAR BANDS. WIDELY SCATTERED STRONG TO SEVERE
GUSTS CAPABLE OF WIND DAMAGE WILL LIKELY BE THE PRIMARY HAZARD, BUT
AN ISOLATED RISK FOR HAIL OR A BRIEF TORNADO IS POSSIBLE WITH THE
STRONGEST CELLS. THIS ACTIVITY WILL LIKELY WEAKEN BY EARLY EVENING
AS IT ENCOUNTERS A SLIGHTLY DRIER AND LESS UNSTABLE AIRMASS WITH
EAST EXTENT.
..CENTRAL TEXAS
SCATTERED SHOWERS AND ELEVATED THUNDERSTORMS ARE EXPECTED THROUGHOUT
MUCH OF THE DAY AS THE COLD FRONT RAPIDLY UNDERCUTS A MOIST AND
UNSTABLE AIR MASS. THE 12 UTC DEL RIO, TX RAOB SHOWS AN 8.2 DEG
C/KM 700-500 MB LAPSE RATE. FORECAST SOUNDINGS SHOW MUCAPE PARCELS
ROOTED IN THE 850-700 MB LAYER, WITH EFFECTIVE DEEP-LAYER SHEAR OF
50-60 KT. ALTHOUGH AN ISOLATED RISK FOR LARGE HAIL APPEARS TO BE
THE MAIN HAZARD WITH THE STRONGER CELLS, THERE HAS BEEN SOME
INDICATION THAT A LOCALIZED RISK FOR SEVERE GUSTS COULD ACCOMPANY
THE STRONGEST CORES. FOR SHORT-TERM DETAILS REGARDING A RISK FOR
HAIL/WIND WITH A FEW STRONGER THUNDERSTORMS THIS MORNING EXTENDING
FROM THE CONCHO VALLEY EAST-NORTHEAST TOWARDS DFW, REFERENCE MCD
#490.
..SMITH/DEAN.. 04/18/2026
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