Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS01 KWNS 261244
SWODY1
SPC AC 261242

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0742 AM CDT TUE MAY 26 2015

VALID 261300Z - 271200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE GREAT LAKES
REGION AND OH VALLEY...

...THERE IS A SLGT RISK OF SVR TSTMS FROM WESTERN OK INTO WEST
CENTRAL TX...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS MUCH OF THE
CENTRAL/SOUTHERN PLAINS...MID MS VALLEY...AND GULF COAST REGIONS...

...SUMMARY...
SCATTERED SEVERE STORMS ARE POSSIBLE TODAY ACROSS PARTS OF THE GREAT
LAKES REGION AND OHIO VALLEY.  ADDITIONAL SEVERE STORMS ARE POSSIBLE
LATE THIS AFTERNOON AND EVENING ACROSS PARTS OF THE SOUTH CENTRAL
PLAINS.

...GREAT LAKES AND OHIO VALLEY...
A STRONG UPPER TROUGH IS ROTATING NORTHEASTWARD TODAY ACROSS MO/IA.
SHOWERS AND THUNDERSTORMS PERSIST AHEAD OF THIS FEATURE OVER IA.
THIS CONVECTION WILL TRACK NORTHEASTWARD AND RESULT IN CLOUDS AND
LIMITED HEATING TODAY OVER MN AND WESTERN WI.  HOWEVER...AREAS
FARTHER SOUTH AND EAST /IL INTO THE OH VALLEY AND LOWER MI/ WILL SEE
POCKETS OF STRONGER HEATING.  THE WIDESPREAD CONVECTION OVER THE
PLAINS ON MONDAY HAS ERODED THE PLUME OF STEEP LAPSE RATES INTO THIS
REGION...WITH FORECAST SOUNDINGS LATER TODAY SHOWING LIMITED
DESTABILIZATION.  NEVERTHELESS...POTENTIAL EXISTS FOR AREAS OF
1000-1500 J/KG MLCAPE VALUES.  WINDS ALOFT WILL BE RELATIVELY STRONG
AND WILL SUPPORT ORGANIZED CONVECTION DESPITE THE WEAK INSTABILITY.

DETAILS OF THE EVOLUTION OF STRONG/SEVERE CONVECTION IN THIS REGION
ARE UNCLEAR DUE TO CONSIDERABLE VARIABILITY IN THE OVERNIGHT CAM
SOLUTIONS.  SCATTERED THUNDERSTORMS WITH A RISK OF GUSTY WINDS IN
THE STRONGEST STORMS WILL BE POSSIBLE THROUGHOUT THE SLIGHT RISK
AREA TODAY.  HOWEVER THE MOST LIKELY SCENARIO FOR MORE ORGANIZED
SEVERE ACTIVITY WOULD BE IF STORMS CAN DEVELOP AND INTENSIFY ALONG
THE SURFACE COLD FRONT OVER SOUTHEAST WI/IL/WESTERN KY DURING THE
MID AFTERNOON.  THOSE STORMS WOULD THEN PROGRESS EASTWARD INTO PARTS
OF KY/IND/OH/LOWER MI THROUGH THE AFTERNOON AND EVENING.  DAMAGING
WINDS APPEAR TO BE THE MAIN THREAT TODAY.

...CENTRAL/SOUTHERN PLAINS...
WATER VAPOR IMAGERY HINTS AT A WEAK SHORTWAVE TROUGH OVER NM.  THIS
FEATURE WILL TRACK EASTWARD TODAY AND BEGIN AFFECTING THE DRYLINE
AREA BY EARLY/MID AFTERNOON.  STRONG HEATING OVER THE EASTERN TX
PANHANDLE...WESTERN OK...AND WESTERN NORTH TX WILL YIELD MLCAPE
VALUES OVER 3000 J/KG AND ONLY A WEAK CAP.  CAMS SUGGEST CONVECTIVE
INITIATION MAY OCCUR RATHER EARLY TODAY AS THE UPPER SYSTEM
APPROACHES.  EFFECTIVE SHEAR IS NOT PARTICULARLY STRONG...BUT
SUFFICIENT FOR A FEW SUPERCELLS GIVEN THE STEEP LAPSE RATES AND
STRONG CAPE VALUES.  LARGE HAIL APPEARS TO BE THE MAIN RISK IN THIS
AREA...BUT DAMAGING WIND GUSTS AND AN ISOLATED TORNADO OR TWO ARE
ALSO POSSIBLE.

..HART/GLEASON.. 05/26/2015



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