220
ACUS02 KWNS 181734
SWODY2
SPC AC 181732
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1232 PM CDT SUN MAY 18 2025
VALID 191200Z - 201200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE CENTRAL AND SOUTHERN PLAINS INTO THE OZARKS...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM MIDDLE
TENNESSEE INTO SOUTH CAROLINA...
..SUMMARY
SEVERE STORMS WITH ALL SEVERE WEATHER HAZARDS ARE EXPECTED FROM THE
CENTRAL/SOUTHERN PLAINS INTO THE OZARKS ON MONDAY.
..CENTRAL/SOUTHERN PLAINS TO THE MID-MISSISSIPPI VALLEY
AN UNCERTAIN AND POTENTIALLY MESSY CONVECTIVE SCENARIO IS APPARENT
ACROSS THE REGION ON MONDAY. AN UPPER TROUGH OVER THE SOUTHERN
ROCKIES WILL BECOME NEGATIVELY TILTED AS IT EJECTS ACROSS THE
CENTRAL/SOUTHERN PLAINS TOWARD THE MID-MS VALLEY. AS THIS OCCURS, A
SOUTHWESTERLY 500 MB JET STREAK AROUND 70-80 KT WILL OVERSPREAD THE
REGION. BY EARLY EVENING AND INTO THE OVERNIGHT HOURS, AN 850-700 MB
LOW-LEVEL JET WILL INCREASE TO AROUND 45-55 KT.
AT THE SURFACE, A SOMEWHAT ELONGATED LOW WILL EXTEND FROM CENTRAL NE
INTO WESTERN KS/OK, WITH SOME FORECAST GUIDANCE SUGGESTING A
SECONDARY LOW PRESSURE CENTER DEVELOPING OVER NORTHWEST OK DURING
LATE AFTERNOON/EARLY EVENING. AT MIDDAY, A DRYLINE WILL EXTEND
SOUTHWARD FROM CENTRAL KS INTO WESTERN OK AND CENTRAL TX WHILE A
COLD FRONT DEVELOP EAST/SOUTHWEST ACROSS NE AND WESTERN KS. A WARM
FRONT WILL EXTEND FROM SOUTHEAST NE INTO NORTHERN MO AND THEN
EASTWARD INTO THE LOWER OH VALLEY. THE WARM FRONT IS NOT FORECAST TO
MOVE MUCH THROUGH THE FORECAST PERIOD. BETWEEN THESE SURFACE
BOUNDARIES, A MOISTURE-RICH BOUNDARY LAYER WILL BE IN PLACE WITH MID
60S TO LOW 70S F DEWPOINTS ACROSS A BROAD ZONE FROM EASTERN KS/OK/TX
TOWARD THE MID-SOUTH. A PLUME OF STEEP MIDLEVEL LAPSE RATES ATOP
THIS MOIST BOUNDARY LAYER WILL RESULT IN STRONG DESTABILIZATION BY
EARLY AFTERNOON, WITH MLCAPE AROUND 2500-3500 J/KG COMMON.
VERTICALLY VEERING, SUPERCELL WIND PROFILES, BECOMING
ELONGATED/STRAIGHT ABOVE 2-3 KM WILL BE PRESENT. LOW-LEVEL
HODOGRAPHS INITIALLY WILL BE SOMEWHAT SMALL, BUT SHOULD BECOME
ENLARGED AS THE LOW-LEVEL JET INCREASES TOWARD EVENING.
CAPPING IS EXPECTED TO ERODE BY EARLY TO MID AFTERNOON ACROSS THE
REGION. CONVECTIVE EVOLUTION IS UNCERTAIN. MOST GUIDANCE DEVELOPS
QUITE A BIT OF THUNDERSTORMS RATHER EARLY IN THE AFTERNOON ACROSS
PORTIONS OF THE OZARKS WHERE 850 MB WARM AIR ADVECTION WILL BE
MAXIMIZED. WHILE INITIAL SUPERCELLS COULD BE POSSIBLE, CELL
INTERACTIONS AND CONSOLIDATION COULD RESULT IN SOME UPSCALE
DEVELOPMENT. REGARDLESS, THIS INITIAL ACTIVITY WILL POSE AN
ALL-HAZARDS SEVERE RISK.
ADDITIONAL SUPERCELLS ARE LIKELY TO DEVELOP ALONG THE SURFACE
DRYLINE FROM CENTRAL/EASTERN KS/OK WHERE STRONG HEATING ALONG/TO THE
WEST OF THE BOUNDARY IS EXPECTED. CONVERGENCE ALONG THE DRYLINE IS
NOT FORECAST TO BE OVERLY STRONG AS LOW-LEVEL FLOW APPEARS TO REMAIN
MORE SOUTHERLY RATHER THAN SOUTHEASTERLY GIVEN A LACK OF STRONGER
SURFACE CYCLOGENESIS. THIS COULD RESULT IN A MESSY STORM MODE DUE TO
STORM INTERACTIONS. NEVERTHELESS, STRONG INSTABILITY, VERY STEEP
LAPSE RATES, AND A FAVORABLY SHEARED ENVIRONMENT WILL SUPPORT
SIGNIFICANT SEVERE STORMS POSE AN ALL-HAZARDS SEVERE RISK. WITH
TIME AND AN INCREASING LOW-LEVEL JET, ONE OR MORE LINEAR BANDS MAY
DEVELOP ACROSS EASTERN KS/OK AND MOVE INTO MO/AR DURING THE
NIGHTTIME HOURS. A CORRIDOR OF GREATER RISK POTENTIAL IS POSSIBLE
SOMEWHERE ACROSS CENTRAL/EASTERN OK/KS BUT UNCERTAINTY REMAINS TOO
GREAT AT THIS TIME FOR A CATEGORICAL OUTLOOK UPGRADE.
..MIDDLE TN INTO PARTS OF SC
AN UPPER RIDGE IS FORECAST TO BE CENTERED OVER THE OH/TN VALLEY AND
GULF COAST REGION, WITH MODEST NORTHWESTERLY FLOW ALOFT SPREADING
OVER THE SOUTHEAST. MOST GUIDANCE DEPICTS A REMNANT MCV MIGRATING
THROUGH THE NORTHWEST FLOW AMID A CORRIDOR OF STRONG INSTABILITY.
DEEP-LAYER FLOW WILL BE UNIDIRECTIONAL, BUT SPEED SHEAR WILL PRODUCE
LONG/STRAIGHT HODOGRAPHS, WITH EFFECTIVE SHEAR MAGNITUDES AROUND
25-35 KT. MODEST MIDLEVEL LAPSE RATES NEARING 7 C/KM, AND STRONG
SURFACE HEATING LEADING TO STEEP LOW-LEVEL LAPSE RATES. ISOLATED
LARGE HAIL AND STRONG/DAMAGING GUSTS WILL BE POSSIBLE AS CONVECTION
DEVELOPS SOUTHEAST ACROSS THE REGION THROUGH THE AFTERNOON.
..LEITMAN.. 05/18/2025
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