Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 241539
SWOMCD
SPC MCD 241539
FLZ000-241815-

MESOSCALE DISCUSSION 1385
NWS STORM PREDICTION CENTER NORMAN OK
1039 AM CDT SUN JUL 24 2016

AREAS AFFECTED...PORTIONS OF CENTRAL AND SOUTH FLORIDA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 241539Z - 241815Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...ISOLATED SEVERE THUNDERSTORMS WILL BE POSSIBLE DURING THE
AFTERNOON HOURS...WITH LOCALLY DMGG WIND GUSTS AND A FEW INSTANCES
OF MARGINALLY SVR HAIL ALSO POSSIBLE. WHILE CONVECTIVE TRENDS WILL
CONTINUE TO BE MONITORED...WW ISSUANCE IS PRESENTLY UNLIKELY. THE
ADDITION OF MRGL RISK IS PLANNED FOR THE 1630Z DAY-1 CONVECTIVE
OUTLOOK.

DISCUSSION...THE AIR MASS ACROSS CENTRAL AND SOUTH FLORIDA COUNTIES
TO DESTABILIZE...OWING TO STRONG INSOLATION/DIABATIC SFC HEATING
OVER THE MAINLAND. THIS IS BEING AIDED BY SEASONABLY RICH LOW-LEVEL
MOISTURE OVER THE AREA...WITH SFC DEWPOINTS IN THE LOWER 70S.
DIURNAL GAINS IN BUOYANCY ARE BEING AMPLIFIED BY THE PRESENCE OF
COLD AIR ALOFT ACCOMPANYING AN UPPER LOW NEAR/E OF LAKE OKEECHOBEE.
THE H5 TEMPERATURE AT MIAMI BASED ON THE 12Z RAOB IS -8.9C...WHICH
IS AROUND/JUST COLDER THAN THE 10TH PERCENTILE VALUE FOR THIS TIME
OF YEAR -- HIGHLIGHTING THE ANOMALOUSLY COLD AIR ALOFT.

A BAND OF DISORGANIZED CONVECTION COILING AROUND THE SRN SEMICIRCLE
OF THE CYCLONIC ENVELOPE SURROUNDING THE UPPER LOW...AND ASSOCIATED
CLOUD DEBRIS...ARE MITIGATING STRONGER DESTABILIZATION ACROSS FAR S
FLORIDA -- ESPECIALLY NEAR/S OF A LINE FROM CORAL GABLES TO
CHOKOLOSKEE. THE STRONGEST SFC HEATING IS ONGOING N OF A LINE FROM
NEAR BOCA RATON/FORT LAUDERDALE WWD TO NAPLES -- AND NWD INTO THE
CNTRL FL PENINSULA. VISIBLE SATELLITE LOOPS SUGGEST A RECENT
BLOSSOMING OF BOUNDARY-LAYER CUMULUS IN THESE AREAS -- LOCALLY
AGITATED OVER INLAND AREAS ADJACENT TO BODIES OF WATER OWING TO
BAROCLINICITY ASSOCIATED WITH SEA-BREEZE BOUNDARIES.

SCATTERED TSTMS WILL LIKELY EVOLVE FROM THIS ACTIVITY WITHIN THE
NEXT FEW HOURS ESPECIALLY AFTER 17Z -- WITH TSTM COVERAGE/INTENSITY
PEAKING IN THE 19Z-23Z TIME FRAME. ANTECEDENT
DIURNAL-HEATING-SUPPORTED MLCAPE WILL LIKELY REACH 1500-2500
J/KG...WHICH WILL SUPPORT VIGOROUS UPDRAFTS -- AIDED BY MODERATE
MID-LEVEL LAPSE RATES. THESE LAPSE RATES -- E.G. 6.7 C/KM IN THE
H7-H5 LAYER -- WILL OFFER SUFFICIENT NORMALIZED CAPE FOR STORM-SCALE
UPWARD ACCELERATIONS TO BE ENHANCED TODAY...AND HAIL REACHING
QUARTER SIZE CANNOT BE RULED OUT. AMPLE PRECIPITATION-LOADING
ASSOCIATED WITH PW AROUND 2 INCHES WILL ALSO SUPPORT WET MICROBURSTS
CAPABLE OF LOCALLY DMGG WIND GUSTS.

DEEP SHEAR WILL BE WEAK...THOUGH SLIGHTLY ENHANCED HIGH-LEVEL FLOW
PERIPHERAL TO THE UPPER LOW WILL ENCOURAGE CONVECTIVE
VENTING/SUSTAINABILITY. THE LACK OF OVERALL CONVECTIVE ORGANIZATION
SHOULD PRECLUDE WW ISSUANCE. HOWEVER...WWD/NWWD-MOVING TSTM CLUSTERS
WILL OFFER AT LEAST ISOLATED SVR POTENTIAL THROUGH THE LATE
AFTERNOON HOURS.

..COHEN/WEISS.. 07/24/2016

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

ATTN...WFO...MFL...MLB...TBW...

LAT...LON   26048030 25968128 26838230 27648268 28208261 28358146
            27998066 27148016 26048030




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