National Weather Service Weather Forecast Office

Area Forecast Discussion

986
FXUS64 KOHX 200435 AAC
AFDOHX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NASHVILLE TN
1135 PM CDT WED JUN 19 2013

.UPDATE...FOR 06Z AVIATION DISCUSSION.
&&

.AVIATION...06Z AVIATION DISCUSSION.
UNCERTAINTIES...MVFR/IFR FOG POTENTIAL CSV 20/09Z-20/13Z AND IMPACTS OF ISO
SHWRS/TSTMS TAF SITES 20/15Z-21/02Z. OVERALL SFC RIDGING INFLUENCES AND
GENERALLY DRY NWLY FLOW ALOFT RESULT IN MAINLY VFR CONDITIONS THRU 21/06Z.
BEST OVERALL LOW LEVEL MOISTURE POOLING POTENTIAL...ALONG WITH CALMS WINDS
AND RADIATIONAL AFFECTS...AT CSV...MVFR FOG REDUCED VSBYS 20/05Z AND IFR
REDUCED FOG VSBYS 20/09Z. ISO SHWRS/TSTMS POSSIBLE 20/15Z-21/02Z...BUT
PINPOINTING ACTUAL DEVELOPMENTAL LOCATIONS STILL QUITE UNCERTAIN PER
CONVECTION DRIVEN BY MAINLY LOCAL DIURNAL/LIFTING MECHANISM AFFECTS.
&&

.PREV DISCUSSION... /ISSUED 649 PM CDT WED JUN 19 2013/

UPDATE...FOR 00Z AVIATION DISCUSSION.

AVIATION...00Z AVIATION DISCUSSION.
UNCERTAINTIES...MVFR/IFR FOG POTENTIAL CSV 20/09Z-20/13Z AND IMPACTS OF ISO
SHWRS/TSTMS TAF SITES. OVERALL SFC RIDGING RIDGING INFLUENCES ALONG WITH
GENERALLY DRY NWLY FLOW ALOFT WILL RESULT IN VFR CONDITIONS THRU 20/24Z.
LOOKS LIKE BEST LOW LEVEL MOISTURE POOLING POTENTIAL...ALONG WITH CALMS WINDS
AND RADIATIONAL AFFECTS WILL BE AT CSV...AND HAVE THUS MENTIONED MVFR FOG
REDUCED VSBYS BY 20/05Z AND IFR REDUCED FOG REDUCED VSBYS BY 20/09Z. ISO
SHWRS/TSTMS POSSIBLE FROM 20/15Z-20/24Z...BUT PINPOINTING ACTUAL DEVELOPMENTAL
LOCATION QUITE UNCERTAIN AT THIS TIME PER CONVECTION BEING DRIVEN BY MAINLY
LOCAL DIURNAL AND LIFTING MECHANISM AFFECTS.

PREV DISCUSSION... /ISSUED 643 PM CDT WED JUN 19 2013/

UPDATE...
A FEW ISOL SHOWERS HAVE DEVELOPED OVER THE PAST FEW HOURS.
HOWEVER...THE CONVECTION IS SHORT LIVED AND APPEARS TO BE DYING OUT.
MEAN STORM MOTION IS A SLOW DRIFT TOWARD THE SOUTHEAST. LAPS DOES
REVEAL STRONGER CAPES OVER WESTERN TN WHERE THE STRONGEST...BUT
STILL ISOL...CONVECTION IS OCCURRING. LATEST LAPS TRENDS DO SHOW
DECREASING CAPES AND THE LATEST HRRR LOOP SHOWS NO REDEVELOPMENT
OVERNIGHT.

FOR THE FORECAST...WILL WAIT UNTIL ABOUT 8PM OR SO...AND THEN
UPDATE AND REMOVE THE EVENING CONVECTION. REMAINDER OF FCST
APPEARS TO BE IN GOOD SHAPE. LOW DEW POINT DEPRESSIONS SHOULD NOT
BE AN ISSUE OVERNIGHT. ALSO...TOVER VALUES LOOK NO LOWER THAN A -3
AT CKV. VSBYS SHOULD REMAIN AOA 1SM SO NO NEED TO INCLUDE FOG IN
FCST.

PREV DISCUSSION... /ISSUED 239 PM CDT WED JUN 19 2013/

DISCUSSION...
STARTING TO SEE A FEW CELLS DEVELOPING IN FAR NORTHEAST ARKANSAS AND
BOOTHEEL AREA OF MISSOURI...THIS IN AN AREA OF -7 LI`S AND SBCAPE
OF 2500 J/KG. ALSO LIGHT SURFACE WIND CONVERGENCE INTO THAT AREA
AT 19Z. WE DO HAVE ONE OR TWO CELLS HERE IN THE MID STATE IN
MARSHALL COUNTY AND IN VAN BUREN AND WHITE COUNTIES. NOT MUCH IN
THE WAY OF MOVEMENT ON ANY OF THIS STUFF BUT THEY DO APPEAR TO BE
SINKING SLOWLY SOUTH. GOOD CU FIELD ACROSS KENTUCKY AND TENNESSEE
THIS AFTERNOON BUT AT THIS TIME VERTICAL DEVELOPMENT IS LACKING
ACROSS MUCH OF THE AREA. EXPECT ISOLATED ACTIVITY TO CONTINUE
DEVELOPING THROUGH THE AFTERNOON AND INTO THE EARLY PART OF THE
EVENING THEN DISSIPATE AROUND SUNSET. WILL KEEP A DRY FORECAST FOR
TONIGHT. NOT ANTICIPATING ANY FOG ISSUES SINCE SLIGHTLY DRIER AIR
WILL BE FILTERING INTO THE MID STATE FROM THE NORTH. SURFACE HIGH
SHIFTS EAST AND OFF THE ATLANTIC SEABOARD ON THURSDAY BUT THERE
WILL BE ENOUGH MOISTURE IN THE TROPOSPHERE FOR ISOLATED STORMS IN
THE AFTERNOON AND EVENING AS TEMPS WARM UP TO AROUND 90 WITH
LOWER 90S ALONG THE ALABAMA BORDER AND MIDDLE 80S ON THE PLATEAU.

FRIDAY WILL USHER IN THE FIRST DAY OF SUMMER WHICH BEGINS AT 12:04
AM C.D.T. (JUST AFTER MIDNIGHT THURSDAY NIGHT INTO FRIDAY MORNING).
THE WEATHER WILL ALSO FEEL SUMMERY FRIDAY THROUGH THE WEEKEND AS
SURFACE RIDGE FROM THE ATLANTIC TAKES ON THE LOOK OF A BERMUDA
HIGH WHILE A SOMEWHAT DIRTY UPPER RIDGE BUILDS THIS WAY FROM
SOUTHERN AND CENTRAL PLAINS. THE 5-WAVE GFS 500 MBAR PATTERN
FRIDAY INTO NEXT WEEK STRENGTHENS THE ATLANTIC RIDGE ACROSS
FLORIDA AND GULF REGION WHICH MEANS TEMPS AVERAGING ABOVE NORMAL
FOR THE MID STATE. GFS ALSO HAS 20 TO 30 PERCENT RAIN CHANCES FOR THE
MID STATE JUST ABOUT EACH DAY THROUGH THE WEEKEND INTO THE FIRST
OF NEXT WEEK.

BOYD

&&

.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$
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