DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 180048
SWODY1
SPC AC 180046

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0746 PM CDT SAT AUG 17 2013

VALID 180100Z - 181200Z

...NO SVR TSTM AREAS FORECAST...

...NRN PLAINS...
THE LATEST WATER VAPOR IMAGERY SHOWS A WELL-DEFINED SHORTWAVE TROUGH
CURRENTLY MOVING THROUGH THE NRN HIGH PLAINS. AS THE SHORTWAVE
TROUGH APPROACHES FROM THE WEST...ISOLATED THUNDERSTORMS COULD
DEVELOP ALONG A COLD FRONT IN NRN ND LATER THIS EVENING. FORECAST
SOUNDINGS AT 06Z NEAR THE CANADIAN-ND BORDER SHOW MLCAPE IN THE 1500
TO 2000 J/KG RANGE WITH 30-40 KT OF DEEP LAYER SHEAR. THIS
ENVIRONMENT ALONG WITH STEEP MID-LEVEL LAPSE RATES COULD SUPPORT
SEVERE THUNDERSTORM DEVELOPMENT. HOWEVER...MUCH OF THE SHORT-TERM
GUIDANCE KEEPS CONVECTIVE COVERAGE ISOLATED WHICH ALONG WITH
DECREASING INSTABILITY DURING THE OVERNIGHT PERIOD SHOULD KEEP ANY
SEVERE THREAT CONFINED TO A SMALL AREA. HAIL AND STRONG GUSTY WINDS
WOULD BE THE PRIMARY THREATS.

...SE GA/NRN FL...
A CLUSTER OF STRONG TO MARGINALLY SEVERE THUNDERSTORMS IS ONGOING IN
SERN GA LOCATED AHEAD OF A SUBTLE IMPULSE MOVING NNEWD OUT OF THE
NERN GULF OF MEXICO. THE STORMS ARE LOCATED ON THE NRN EDGE OF
MODERATE INSTABILITY WHERE MESOANALYSIS IS ESTIMATING MLCAPE AROUND
1500 J/KG. THIS COMBINED WITH SFC DEWPOINTS IN THE MID 70S F AND 20
TO 30 KT OF UNIDIRECTIONAL FLOW IN THE LOW TO MID-LEVELS EVIDENT ON
THE TALLAHASSEE WSR-88D VWP SHOULD BE ENOUGH FOR ISOLATED WET
DOWNBURSTS FOR ANOTHER HOUR OR SO.

...CNTRL GULF COAST...
THE LATEST WATER VAPOR IMAGERY SHOWS SEVERAL IMPULSES MOVING NNEWD
OUT OF THE CNTRL GULF OF MEXICO WITH A VORTICITY MAX LOCATED JUST TO
THE SOUTH OF NEW ORLEANS. AHEAD OF THIS FEATURE...NUMEROUS
THUNDERSTORMS ARE ONGOING AND SHOULD MOVE TOWARD THE CNTRL GULF
COAST BY LATE THIS EVENING AND INLAND DURING THE OVERNIGHT PERIOD.
ONSHORE FLOW SHOULD RESULT IN INCREASING SFC DEWPOINTS FROM NEW
ORLEANS EWD TO TALLAHASSEE. IN RESPONSE...INSTABILITY SHOULD
INCREASE WHICH ALONG WITH 20 TO 30 KT OF LOW-LEVEL FLOW COULD BE
ENOUGH FOR A MARGINAL THREAT FOR DAMAGING WIND GUSTS LATER TONIGHT.

...SCNTRL AZ...
NUMEROUS THUNDERSTORMS ARE ONGOING ALONG THE MOGOLLON RIM EARLY THIS
EVENING. THIS ACTIVITY SHOULD TRANSLATE SLOWLY SWD ACROSS SCNTRL AZ
WHERE MESOANALYSIS IS SHOWING MODERATE INSTABILITY WITH MLCAPE
AROUND 1500 J/KG. THIS COMBINED WITH 0-3 KM LAPSE RATES EXCEEDING
9.0 C/KM WITH LARGE TEMP-DEWPOINT SPREADS SHOULD HELP ACCELERATE
DOWNDRAFT SPEEDS ENOUGH FOR A MARGINAL WIND DAMAGE THREAT WITH THE
MORE INTENSE CELLS.

..BROYLES.. 08/18/2013

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