Severe Storm Outlook Narrative (AC)
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435
ACUS11 KWNS 051830
SWOMCD
SPC MCD 051829
FLZ000-GAZ000-ALZ000-052030-

MESOSCALE DISCUSSION 1867
NWS STORM PREDICTION CENTER NORMAN OK
1229 PM CST MON DEC 05 2016

AREAS AFFECTED...ALABAMA AND FLORIDA GULF COAST

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 051829Z - 052030Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...IT APPEARS THAT THE ENVIRONMENT MAY BECOME INCREASINGLY
CONDUCIVE TO SEVERE STORMS BY 21-23Z...POSSIBLE INCLUDING A SUPERCELL
OR TWO CAPABLE OF PRODUCING TORNADOES.  IT IS NOT YET CERTAIN THAT A
WATCH WILL BE NEEDED...BUT TRENDS ARE BEING MONITORED FOR THIS
POSSIBILITY.

DISCUSSION...WELL IN ADVANCE OF THE MID-LEVEL CLOSED LOW NOW TURNING
NORTHEASTWARD ACROSS THE RIO GRAND VALLEY...LOWER/MID TROPOSPHERIC
WARM ADVECTION HAS BEEN SUPPORTING CONSIDERABLE THUNDERSTORM
DEVELOPMENT ACROSS THE NORTH CENTRAL GULF COAST.  THIS INCLUDES A
RECENT INCREASE IN THUNDERSTORM ACTIVITY SOUTH OF THE ALABAMA AND
FLORIDA COAST...WHICH LIKELY WILL CONTINUE SPREADING NORTHWARD...AND
INLAND THIS AFTERNOON.

WHILE RAIN APPEARS TO BE REINFORCING A RELATIVELY COOL/STABLE
BOUNDARY LAYER ACROSS MOST COASTAL AREAS NEAR AND WEST OF MOBILE
BAY...THE BOUNDARY LAYER ACROSS MUCH OF THE FLORIDA PANHANDLE IS
ALREADY CONSIDERABLY WARMER AND MORE MOIST.  THE LATEST RAPID
REFRESH SUGGESTS FURTHER WARMING AND MOISTENING IS POSSIBLE THROUGH
THE REMAINDER OF THE AFTERNOON...EVEN AS CONVECTION OVERSPREADS THE
REGION.  THIS IS EXPECTED TO ACCOMPANY STRENGTHENING SOUTHERLY
LOW-LEVEL FLOW (INCLUDING 30-40+ KT AT 850 MB) EAST OF A DEVELOPING
SURFACE LOW NEAR THE LOUISIANA COAST.

FORECAST SOUNDINGS ACROSS THE WESTERN FLORIDA PANHANDLE SUGGEST THAT
INCREASING BOUNDARY LAYER INSTABILITY COUPLED WITH ENLARGING...
CLOCKWISE-CURVED LOW-LEVEL HODOGRAPHS COULD LEAD TO A RISK FOR
SUPERCELLS CAPABLE OF PRODUCING TORNADOES BY THE 21-23Z TIME FRAME.
DEEP LAYER SHEAR IS ALREADY POTENTIAL STRONG (FOR BOUNDARY LAYER
BASED STORMS) ACROSS THIS REGION...BENEATH 40-50 KT SOUTHWESTERLY 500
MB FLOW.

..KERR/HART.. 12/05/2016

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

ATTN...WFO...TAE...MOB...

LAT...LON   30728755 30958680 31028507 30608443 29798468 29768628
            29668718 30088774 30728755




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