Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 290449
SWOMCD
SPC MCD 290448
FLZ000-290615-

MESOSCALE DISCUSSION 0487
NWS STORM PREDICTION CENTER NORMAN OK
1148 PM CDT TUE APR 28 2015

AREAS AFFECTED...PARTS OF SRN FL AND THE KEY

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 290448Z - 290615Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...FREQUENT CLOUD TO GROUND LIGHTNING...MARGINALLY SEVERE
HAIL AND PERHAPS GUSTY WINDS PERHAPS APPROACHING SEVERE LIMITS MAY
ACCOMPANY AN EVOLVING CLUSTER OF STORMS WHICH COULD REACH NAPLES AND
ADJACENT FLORIDA GULF COASTAL AREAS BY 07-08Z.  A SEVERE WEATHER
WATCH PROBABLY IS NOT NEEDED...BUT TRENDS WILL BE MONITORED.

DISCUSSION...MID/UPPER FORCING DOES NOT APPEAR PARTICULARLY
STRONG...BUT INFRARED SATELLITE IMAGERY INDICATES THAT CLOUD TOPS
CONTINUE TO COOL IN ASSOCIATION WITH AN EVOLVING MESOSCALE
CONVECTIVE SYSTEM NEAR A WEAK FRONTAL WAVE WEST OF THE FLORIDA
PENINSULA.  FREQUENT CLOUD TO GROUND LIGHTNING IS EVIDENT IN 5
MINUTE LIGHTNING DATA WITH THE STRONGEST...FORWARD PROPAGATING
PORTION OF THE CLUSTER WHICH APPEARS LIKELY TO REACH THE NAPLES FL
AREA TOWARD 07-08Z.  MRMS MESH DATA SUGGEST THAT THIS
CONVECTION...AND THE STRONGER CORES IN CONVECTION WITHIN THE
DOWNSTREAM WARM ADVECTION WING...MAY BE PRODUCING AT LEAST
MARGINALLY SEVERE HAIL...IN THE PRESENCE OF MODEST CAPE AND AND
MODERATELY STRONG VERTICAL SHEAR BENEATH 35-40 KT 500 MB FLOW.  IT
DOES NOT APPEAR OUT OF THE QUESTION THAT PEAK GUSTS COULD AT LEAST
APPROACH SEVERE LIMITS AS THE DEVELOPING COLD POOL ADVANCES INTO
SOUTHERN FLORIDA GULF COASTAL AREAS.  IT REMAINS A BIT MORE UNCLEAR
HOW FAR INLAND THIS WILL REMAIN AN APPRECIABLE THREAT.

..KERR/THOMPSON.. 04/29/2015

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...MFL...KEY...TBW...

LAT...LON   26808331 26658252 26388191 26158077 26008050 25618048
            25048075 24498177 25258288 25548378 25988433 26378375
            26808331



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