DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 170541
SWODY1
SPC AC 170540

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1140 PM CST SUN JAN 16 2011

VALID 171200Z - 181200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN AND
CNTRL FL PENINSULA...

...SRN AND CNTRL FL PENINSULA...
A LARGE-SCALE UPPER-LEVEL TROUGH OVER THE WRN GULF OF MEXICO WILL
MOVE QUICKLY EWD TODAY. IN RESPONSE TO THE APPROACHING UPPER-LEVEL
TROUGH...A LOW-LEVEL JET WILL DEVELOP THIS MORNING OVER THE ERN GULF
OF MEXICO AND STRENGTHEN QUICKLY AFTER DAYBREAK ON THE WRN EDGE OF
THE FL PENINSULA. THIS WILL HELP TO INCREASE CONVECTION WITH
THUNDERSTORM ACTIVITY BEGINNING TO AFFECT THE WRN PENINSULA DURING
THE 12Z TO 15Z TIMEFRAME. DUE TO THE TIMING OF THE CONVECTION...THE
GREATEST SFC HEATING THIS MORNING SHOULD OCCUR OUT AHEAD OF THE
STORMS AROUND LAKE OKEECHOBEE AND NEAR MIAMI.

ALTHOUGH THE AIRMASS HAS YET TO MOISTEN...SFC DEWPOINTS ARE FORECAST
TO REACH THE MID 60S F BY EARLY AFTERNOON ACROSS SRN FL. BECAUSE OF
THIS...ETA-KF FORECAST SOUNDINGS DEVELOP MODERATE INSTABILITY BY
AFTERNOON WITH MLCAPE VALUES REACHING THE 1000 TO 1500 J/KG RANGE.
IN ADDITION...A 60 TO 75 KT MID-LEVEL JET IS FORECAST TO MOVE ACROSS
THE CNTRL PENINSULA THIS AFTERNOON. THIS FEATURE WILL REINFORCE
MODERATE DEEP LAYER SHEAR ACROSS SOUTH FL HELPING TO PRODUCE AN
ENVIRONMENT SUPPORTIVE OF ROTATING STORMS. AS THE LOW-LEVEL JET
BROADENS AND DEVELOPS SWD ACROSS THE SOUTHEAST COAST THIS
AFTERNOON...LOW-LEVEL SHEAR MAY BECOME STRONG ENOUGH FOR AN ISOLATED
TORNADO THREAT. IF SOME CELLS CAN REMAIN DISCRETE...THEN A TORNADO
OR TWO COULD OCCUR AROUND MIAMI THIS AFTERNOON AND THE WRF-NMM
HI-RES MODEL IS IN AGREEMENT WITH THIS IDEA. SUPERCELLS SHOULD ALSO
BE CAPABLE OF PRODUCING WIND DAMAGE AND THIS MAY BECOME THE FAVORED
THREAT IF A LINE-SEGMENT CAN ORGANIZE LATE THIS AFTERNOON. FURTHER
NORTH ACROSS THE CNTRL PENINSULA...LOW-LEVEL MOISTURE SHOULD BE A
LIMITATION. HOWEVER...THE STRONG SHEAR MAY ENABLE SOME STORMS TO
ROTATE THERE AS WELL.

..BROYLES/ROGERS.. 01/17/2011

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