Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 290858
SWOMCD
SPC MCD 290857
FLZ000-291100-

MESOSCALE DISCUSSION 0488
NWS STORM PREDICTION CENTER NORMAN OK
0357 AM CDT WED APR 29 2015

AREAS AFFECTED...SRN FL

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 290857Z - 291100Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...STORMS MAY POSE A THREAT FOR MAINLY STRONG TO MARGINALLY
SEVERE WIND GUSTS OVER S FL EARLY THIS MORNING. A BRIEF...WEAK
TORNADO ALSO CANNOT BE RULED OUT.

DISCUSSION...EARLY THIS MORNING A BROKEN BAND OF STORMS WITH
EMBEDDED MARGINAL SUPERCELL STRUCTURES WAS LOCATED OVER S FL FROM
NORTH OF FLAMINGO TO NEAR KEY LARGO. THIS BAND OF STORMS APPEARS TO
BE DEVELOPING IN ASSOCIATION WITH MODEST ISENTROPIC ASCENT ABOVE A
REMNANT BOUNDARY LOCATED OFFSHORE. VWP DATA FROM MIAMI SHOW WEAK
/AOB 20 KT/ WINDS THROUGH LOWEST 3 KM WHICH IS LIMITING HODOGRAPH
SIZE...BUT SHEAR THROUGH A DEEPER LAYER IS IN EXCESS OF 40 KT. WHILE
THIS WIND PROFILE IS SUPPORTIVE OF MID-LEVEL UPDRAFT ROTATION...IT
IS NOT CONDUCIVE FOR SUSTAINED LOW-LEVEL MESOCYCLONES WHICH IS A
LIMITING FACTOR FOR MORE THAN JUST A BRIEF...WEAK TORNADO OR
WATERSPOUT.

OTHERWISE...LINEAR MCS OVER SWRN FL IS ADVANCING SEWD AT AROUND 25
KT. A ROTATING COMMA HEAD STRUCTURE IS EMBEDDED WITHIN THE LINE.
SOME THREAT FOR AT LEAST MARGINALLY SEVERE WIND GUSTS MAY ACCOMPANY
THIS FEATURE AS IT MOVES THROUGH S FL NEXT COUPLE HOURS WHERE THE
ATMOSPHERE REMAINS MODERATELY UNSTABLE WITH 1500 J/KG MUCAPE...BUT
WEAK LAPSE RATES.

..DIAL/CORFIDI.. 04/29/2015

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

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

LAT...LON   25558080 26118023 25068014 24678179 25558080



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