811
FXUS64 KOHX 042341
AFDOHX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
641 PM CDT SAT JUL 4 2009
MESOSCALE UPDATE
BROAD CIRCULATION FROM STORM IN CALLOWAY CO KY AT 2326Z OFF PAH DOPPLER.
MESO POPPED OFF IN EASTERN CALLOWAY CO AT 2329Z OFF OHX DOPPLER. THIS
STORM HAS PRODUCED REPORTS OF FUNNEL CLOUDS. HAVE ISSUED TORNADO WARNING
FOR STEWART COUNTY UNTIL 700 PM CDT. THIS STORM IS NOW ENTERING LAND
BETWEEN LAKES AREA. SHOULD BE A TREE DOWNER AS IT PASSES THROUGH
THAT AREA. BOATERS NEED TO GET OFF TENNESSEE AND CUMBERLAND RIVERS
IN STEWART CO IMMEDIATELY.
BOYD
PREV DISCUSSION
/ISSUED 523 PM CDT SAT JUL 4 2009/
MESOSCALE UPDATE...
CLUSTER OF STORMS TO THE WEST OF NASHVILLE...FROM ABOUT ASHLAND CITY
WEST TO WAVERLY WITH A RATHER INTENSE CELL OVER SOUTHEAST DICKSON
CO NEAR BURNS. CELL OVER BURNS STILL HAS SUSPENDED CORE. WARNING
REMAINS IN EFFECT UNTIL 530 PM FOR SOUTHEAST DICKSON AND NORTHEAST
HICKMAN CO'S.
MSAS SURFACE LI'S HAVE LOWERED SOMEWHAT FROM NASHVILLE EASTWARD. ALSO...
THERE APPEARS TO BE SOME SURFACE BASED NEGATIVE ENERGY (CIN) FROM
ABOUT I65 EASTWARD. AS STORMS TO THE WEST NASHVILLE MOVE EAST OF
I65 THEY SHOULD WEAKEN AS INSTABILITY IS MUCH WEAKER.
BOYD
PREV DISCUSSION... /ISSUED 435 PM CDT SAT JUL 4 2009/
MESOSCALE UPDATE...
-6 LIFTED INDICES STRUNG OUT ACROSS NORTHWEST MIDDLE TN GENERALLY ALONG
AND NORTH OF INTERSTATE 40 AS FAR EAST AS I65. ONE STORM IN SOUTHWEST
SUMNER CO HAS 60 DBZ SUSPENDED AROUND 11K. THIS RIGHT ON EASTERN EDGE
OF BEST LI'S. STORM MOVEMENT FROM 270/30KTS.
BOYD
PREV DISCUSSION... /ISSUED 244 PM CDT SAT JUL 4 2009/
DISCUSSION...
SFC LOW OVER NORTHERN MO THIS AFTERNOON WITH GOOD LOW LEVEL
CONVERGENCE EVIDENT ON THE SFC ANALYSIS CHARTS ACROSS SOUTHERN
IL...SW IN AND ALONG THE OH RIVER. BEST SFC CONVERGENCE ZONE TO MOVE
EASTWARD TONIGHT AS OPPOSED TO SOUTHEASTWARD. BEST PRECIP ON THE
NORTHERN SIDE OF THE SYSTEM WILL OCCUR GENERALLY ALONG AND JUST
SOUTH OF THE 850 MB BOUNDARY. OF ADDITIONAL NOTE...PVA CORRIDOR TO
SET UP GENERALLY SW OF THE MID STATE. THUS...ALL IN ALL...THE
HEAVIEST PRECIP WILL REMAIN NORTH OF THE MID STATE AND SOUTHWEST OF
THE MID STATE.
SFC LOW LOOKS TO BE DISPLACED FROM THE PVA CORRIDOR AND THUS...THE
SFC LOW WILL WEAKEN SOME AFTER 06Z GIVEN THE LACK OF IMMEDIATE UPPER
SUPPORT.
NEVERTHELESS...FRONTAL BOUNDARY WILL SWING THROUGH BUT NOT UNTIL
SUNDAY AFTERNOON. CURRENT PRESSURE FALLS DO EXIST IN ADVANCE OF THE
BOUNDARY BUT ARE UNIMPRESSIVE. AS THE BOUNDARY SWINGS
THROUGH...ENERGY ALONG THE SFC FRONT BECOMES MORE ELONGATED THEREBY
REDUCING THE ASSOCIATED SFC FORCING. SO...HEAVIER PRECIP OVER A
GENERAL AREA APPEARS TO BE ABSENT FROM THE EQUATION ONCE AGAIN.
OVERALL...CATEGORICAL POPS WILL STILL BE INCLUDED TONIGHT GIVEN THE
APPROACHING MOISTURE AXIS WITH LIKELY POPS FOR TOMORROW. IT JUST
LOOKS AS THOUGH THE HEAVIEST ACTIVITY WILL REMAIN NORTH AND
SOUTHWEST OF THE MID STATE.
AS FOR TIMING OF TONIGHT'S ACTIVITY. PRECIP PROBABILITIES WILL
INCREASE WITH TIME WITH THE CATEGORICAL IMPACT GEARED TOWARD THE
AFTER MIDNIGHT HOURS. TOUGH CALL FOR THE FIREWORKS ACROSS THE AREA
BUT I WILL INCLUDE A CHC OF SHOWER AND TSTMS THIS EVENING...WITH THE
BEST CHANCE...OF COURSE...BEING ACROSS THE NW ZONES. FOR BNA IN
PARTICULAR...RAINFALL MAY HOLD OFF UNTIL 9 OR 10 PM.
SFC FRONT TO BECOME MORE PARALLEL TO UPPER FLOW WITH TIME SO WE WILL
SEE THE FRONT SLOW DOWN EVEN FURTHER AS IT REACHES NORTHERN AL
SUNDAY NIGHT. WILL THEREFORE KEEP 20-40 POPS GOING FOR SOUTH MIDDLE
TN THROUGH MON NT AND A SLT CHC NORTH THROUGH SUN NT.
FOR TEMPS...MAV LOOKS TOO COOL FOR LOWS AS THAT MODEL APPEARS A BIT
SLUGGISH IN REGARD TO THE INCREASING DEWPOINT TREND. WILL THEREFORE
GO ABOVE THE MAV MINS.
IN THE EXT FCST...UPPER RIDGE AXIS TO LEAN TOWARD TN TOWARD THE END
OF NEXT WEEK. WILL START OUT THE PERIOD WITH A RATHER DEEP DRY LAYER
IN PLACE AS A SFC RIDGE CONTROLS. THEN...AS SFC RIDGE SHIFTS
EAST...LOW LEVEL HUMIDITIES WILL INCREASE ALONG WITH WARMER
MID/UPPER LEVEL TEMPS...COMPLIMENTS OF THE APPROACHING UPPER RIDGE.
AT THE TAIL END OF THE EXTENDED...WEAK NW FLOW MAY SLIP A BOUNDARY
ACROSS US. THUS...WILL INCLUDE A SLT CHC OF SHOWERS AND STORMS FOR
SATURDAY. FOR TEMPS...WILL GO ABOVE THE MEX AS IT CONTINUES TO
MIGRATE TOWARD CLIMO WHILE THE EURO AND THE GFS POINT TOWARD
INCREASING HEIGHTS.
OHX WATCHES/WARNINGS/ADVISORIES
NONE.
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