DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1128 AM CST WED FEB 15 2023
VALID 161200Z - 171200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
MISSISSIPPI AND ALABAMA NORTHWARD INTO SOUTHWEST OHIO...
..SUMMARY
WIDELY SCATTERED SEVERE THUNDERSTORMS ARE LIKELY FROM THE CENTRAL
GULF COAST STATES NORTHWARD INTO THE OHIO VALLEY ON THURSDAY.
SEVERAL TORNADOES ARE POSSIBLE OVER MISSISSIPPI AND ALABAMA,
INCLUDING THE RISK FOR ISOLATED STRONG TORNADOES.
..SYNOPSIS
AN ELONGATED POSITIVE-TILT UPPER TROUGH WILL EXTEND FROM THE UPPER
GREAT LAKES INTO THE SOUTHERN PLAINS BY 00Z, WITH A PRIMARY/LEADING
MIDLEVEL JET OVER 110 KT FROM MO INTO LOWER MI AND A DRY SLOT
DEVELOPING FROM ST. LOUIS TO LAKE ERIE. AFTER 00Z, A SECONDARY WAVE
WILL MOVE FROM THE SOUTHERN PLAINS TOWARD THE LOWER MS VALLEY, WITH
INCREASING HEIGHT FALLS AND STRENGTHENING WINDS ALOFT ACROSS THE
SOUTHEASTERN STATES.
AT THE SURFACE, LOW PRESSURE WILL MOVE FROM SOUTHERN IL INTO OH BY
00Z, REACHING NEW ENGLAND BY FRIDAY MORNING. A COLD FRONT WILL
EXTEND SOUTH FROM THE LOW, CROSSING THE MS RIVER BY LATE MORNING,
AND PROCEEDING INTO THE MID OH/TN VALLEYS BY LATE AFTERNOON.
MEANWHILE, A WARM FRONT WILL EXTEND EAST FROM THE LOW THURSDAY
MORNING, ACROSS CENTRAL IN AND OH. SOUTHERLY WINDS ACROSS THE WARM
SECTOR WILL MAINTAIN A PLUME OF 60S F DEWPOINTS AS FAR NORTH AS THE
SURFACE LOW, WITH MID 60S F ACROSS THE LOWER MS VALLEY. MORE
SUBSTANTIAL MOISTURE WILL BE IN PLACE OVER LA, WITH UPPER 60S F
TRANSLATING EASTWARD ACROSS SOUTHERN MS/AL AND THE FL PANHANDLE BY
FRIDAY MORNING WITH THE COLD FRONT ROUGHLY FROM WESTERN PA TO FL BY
THIS TIME.
A BROAD AREA OF 40-50 KT SOUTHWESTERLY FLOW AT 850 MB WILL EXIST
ATOP THE ENTIRE WARM SECTOR, ENHANCING LOW-LEVEL SHEAR. THE
COMBINATION OF A MOIST AIR MASS AND FAVORABLE SHEAR OVER A LARGE
AREA WILL LIKELY SUPPORT CORRIDORS OF SEVERE STORMS, INCLUDING A FEW
TORNADOES THROUGH THE PERIOD.
..LA...MS...AL
A COLD FRONT WILL MOVE INTO WESTERN MS AND SOUTH-CENTRAL LA BY
MIDDAY, WHERE AMPLE MOISTURE WILL BE IN PLACE. STORMS BOTH ALONG AND
AHEAD OF THE FRONT WILL BE POSSIBLE AS THE AIR MASS WILL BE
UNCAPPED, WITH UPPER 60S F DEWPOINTS LIKELY SUFFICIENT TO SUPPORT
SURFACE-BASED PARCELS. EFFECTIVE SRH AROUND 300 M2/S2 WILL BE COMMON
ALONG THE EASTERN EDGE OF THE INSTABILITY PLUME, AND SUPERCELLS WILL
BE POSSIBLE WITH TORNADO RISK.
AS HEIGHT FALLS AND WINDS ALOFT INCREASE OVERNIGHT, THE COLD FRONT
WILL CONTINUE TO SUPPORT STRONG TO SEVERE STORMS, WITH 50 KT FLOW AT
850 MB AND MID TO UPPER 60S F DEWPOINTS FROM SOUTHERN AL INTO THE FL
PANHANDLE. HODOGRAPHS WILL BE QUITE FAVORABLE FOR TORNADIC
SUPERCELLS, WITH THE PRIMARY MITIGATING FACTOR BEING COOL/MARGINAL
BOUNDARY-LAYER TEMPERATURES.
..OH VALLEY INTO TN
STORMS ARE LIKELY TO BE ONGOING ACROSS MUCH OF TN AND KY, PERHAPS
EXTENDING INTO NORTHERN MS AND ALONG THE AR/MS BORDER, WITHIN A WARM
ADVECTION REGIME BENEATH 50-60 KT 850 MB FLOW. THE INSTABILITY AXIS
WILL BE NEAR THE MS RIVER THURSDAY MORNING, THUS STORMS ACROSS
WESTERN AREAS MAY HAVE TORNADO OR DAMAGING WIND POTENTIAL AT THAT
TIME. MUCH WILL DEPEND ON EXISTING STORM MODES AT THE BEGINNING OF
THE DAY, AS HEATING WILL BE LIMITED, AND OUTFLOW MAY BOTH PROVIDE A
FOCUS FOR NEW DEVELOPMENT OR STABILIZE PORTIONS OF THE WARM SECTOR.
DURING THE AFTERNOON, AREAS OF AIR MASS RECOVERY MAY OCCUR AHEAD OF
THE COLD FRONT AND BEHIND THE EARLY DAY STORMS. IN ADDITION, SOME OF
THE EXISTING STORM COMPLEXES COULD EVOLVE/REORGANIZE ACROSS KY AND
TN. SHEAR PROFILES WILL STRONGLY FAVOR SUPERCELLS WITH TORNADO
THREAT, BUT LITTLE HEATING AND ONGOING PRECIPITATION MAY LIMIT
SURFACE TEMPERATURES.
FARTHER NORTH, A DRY SLOT SHOULD CLEAR OUT MUCH OF THE AREA AROUND
IL AND NORTHERN IN, BUT SOUTHERN IN INTO OH WILL REMAIN SUFFICIENTLY
UNSTABLE FOR SEVERE STORMS GIVEN STRONG SHEAR. THE AREA ALONG AND
EAST OF THE SURFACE LOW TRACK MAY FAVOR ISOLATED SUPERCELLS,
ASSUMING THE SURFACE AIR MASS CAN WARM INTO THE MID 60S F.
..JEWELL.. 02/15/2023
