Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS01 KWNS 241630
SWODY1
SPC AC 241628

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1128 AM CDT SUN JUL 24 2016

VALID 241630Z - 251200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER NERN IL/EXTREME SERN
WI/SWRN LOWER MI AND NRN INDIANA...

...THERE IS A SLGT RISK OF SVR TSTMS OVER ERN CO...

...THERE IS A MRGL RISK OF SVR TSTMS FROM THE GREAT LAKES INTO THE
MIDWEST...

...THERE IS A MRGL RISK OF SVR TSTMS OVER CENTRAL/SRN FL...

...SUMMARY...
SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WIND GUSTS AND
LARGE HAIL WILL BE POSSIBLE OVER PARTS OF EASTERN COLORADO...AND
OVER PARTS OF NORTHEAST ILLINOIS...EXTREME SOUTHEAST
WISCONSIN...SOUTHWEST LOWER MICHIGAN AND NORTHERN INDIANA...MAINLY
DURING THE LATER AFTERNOON AND EVENING.  ISOLATED SEVERE STORMS WILL
BE POSSIBLE ACROSS THE GREAT LAKES AND MIDWEST REGIONS...AND OVER
THE CENTRAL AND SOUTHERN FLORIDA PENINSULA.

...NORTHEAST IL/EXTREME SERN WI/SWRN LOWER MI AND NRN INDIANA...
ONGOING STORMS OVER LOWER MI HAVE GENERATED A COMPOSITE OUTFLOW
BOUNDARY EXTENDING FROM NWRN OH AND NRN INDIANA INTO SRN LAKE MI.
WIDESPREAD CLOUD COVER TO THE NORTH OF THIS BOUNDARY IS EXPECTED TO
LIMIT DIABATIC HEATING AND STRENGTHEN THE THERMAL GRADIENT ALONG THE
COMPOSITE WARM FRONT/OUTFLOW BOUNDARY.  TO THE S/SW OF THIS
BOUNDARY...STRONG HEATING AND DIURNAL DESTABILIZATION WILL OCCUR
WITHIN AN ENVIRONMENT CHARACTERIZED BY AMPLE MOISTURE WITH SURFACE
DEW POINTS IN THE UPPER 70S...RESULTING IN MLCAPE OF 2500-4000 J/KG
LIKELY THIS AFTERNOON.

ALTHOUGH LARGE SCALE ASCENT ASSOCIATED WITH THE UPPER TROUGH
TRANSLATING EWD OVER NRN MN AND LAKE SUPERIOR WILL REMAIN NORTH OF
THIS AREA...WEAK LOW-LEVEL CONVERGENCE ALONG AN APPROACHING COLD
FRONT...POTENTIALLY ENHANCED NEAR A PROJECTED OUTFLOW BOUNDARY/FRONT
INTERSECTION...MAY BE SUFFICIENT TO INITIATE WIDELY SCATTERED
THUNDERSTORMS OVER THIS REGION DURING THE LATE AFTERNOON AND EVENING
HOURS.  MODEST VERTICAL SHEAR WILL PROMOTE A FEW ORGANIZED MULTICELL
CLUSTERS WITH POTENTIAL FOR DAMAGING WIND GUSTS AND LARGE HAIL TO
OCCUR.

...ERN CO...
MOIST UPSLOPE LOW-LEVEL FLOW WILL BECOME BETTER ESTABLISHED ACROSS
THE AREA THIS AFTERNOON AS STRONG HEATING OCCURS OVER THE MOUNTAINS
AND PLAINS...WITH SURFACE DEW POINTS REMAINING IN THE 50S ESPECIALLY
ACROSS THE PLAINS.  STEEP MID-LEVEL LAPSE RATES WILL CONTRIBUTE TO
MODERATE INSTABILITY WITH MLCAPE OF 1000-2000 J/KG DEVELOPING THIS
AFTERNOON.  MODEL CONSENSUS INDICATES STORMS WILL DEVELOP NEAR THE
FRONT RANGE BY MID-AFTERNOON WITH ACTIVITY SPREADING EWD ACROSS THE
PLAINS THROUGH THE EVENING.  STRONG DIRECTIONAL SHEAR WITH HEIGHT
WILL ENHANCE STORM ORGANIZATION WITH MORE INTENSE STORMS CAPABLE OF
PRODUCING LARGE HAIL AND STRONG WIND GUSTS.

...CENTRAL/SRN FL...
AS AN UPPER LOW MOVES WWD ACROSS THE SRN PENINSULA...THUNDERSTORMS
ARE EXPECTED TO CONTINUE DEVELOPING OVER THE CENTRAL/SRN PARTS OF
THE STATE.  RELATIVELY COOL MID-LEVEL TEMPERATURES ARE ENHANCING
LAPSE RATES WITH POTENTIAL FOR ISOLATED STRONG/SEVERE STORMS THIS
AFTERNOON AND EVENING.  SEE MCD 1385 FOR MORE DETAILED INFORMATION.

...PARTS OF NRN/ERN OH INTO WRN PA...
SATELLITE/RADAR ANIMATIONS SUGGEST PRESENCE OF AN MCV OVER NRN OH
THAT IS MOVING SLOWLY EWD.  A FEW STRONGER STORMS ARE ASSOCIATED
WITH THE MCV AT THIS TIME...AND CONVECTIVE DEVELOPMENT MAY BE
ENHANCED DOWNSTREAM FROM THE MCV INTO THIS EVENING.  FOR THIS
REASON...HAVE EXTENDED THE MARGINAL RISK AREA FARTHER E/SE ACROSS
ERN OH INTO WRN PA WHERE STORMS CAPABLE OF PRODUCING GUSTY WINDS AND
MARGINALLY SEVERE HAIL MAY OCCUR.

..WEISS/DEAN.. 07/24/2016

$$



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