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000
FXUS64 KOHX 170457 AAC
AFDOHX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NASHVILLE TN
1157 PM CDT THU MAY 16 2013

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

.AVIATION...06Z AVIATION DISCUSSION.
UNCERTAINTIES...ACTUAL SHWRS/TSTMS LOCATION DEVELOPMENT...TRANSITIONAL TIMING
FROM VFR/MVFR CEILINGS AND ACTUAL COVERAGE OF SHWRS/TSTMS 17/10Z-18/06Z. STILL
EXPECTING OVERALL INCREASING INSTABILITY...MOISTURE...AND LIFTING MECHANISM THRU
18/06Z...ESPECIALLY AFTER 17/10Z...AND WILL CONTINUE WITH A GENERAL TREND OF
VCSH THRU 17/11Z...TRANSITIONING TO CAT SHWRS/TSTMS 17/11Z-18/06Z...AS OPENING
UPPER LEVEL LOW/UPPER LEVEL TROUGH MOVES ACROSS WRN COUNTIES AND THEN ACROSS
REST OF MID STATE. STILL BELIEVE THAT ACTIVITY MAY BE MORE DIURNAL BASED ERN
PORTIONS OF MID STATE AS OF 17/12Z-18/00Z AND THUS WILL CONTINUE WITH VCTS
REMARKS AS LOCATION DEVELOPMENT UNCERTAIN THRU AT LEAST 18/00Z. CAT SHWRS/TSTMS
ALL AREAS EXPECTED BETWEEN 18/00Z-18/06Z.
&&

.PREV DISCUSSION.../ISSUED 658 PM CDT THU MAY 16 2013/

UPDATE...
JUST ISOLATED SHOWER AND TSTM ACTIVITY THUS FAR ACROSS THE MID
STATE THIS EVENING. BETTER COVERAGE OF SHOWERS AND TSTMS EXISTS
BACK TO OUR WEST ACROSS AR. MODELS ARE IN AGREEMENT WITH THIS
DEEPER AREA OF MOISTURE SPREADING EASTWARD AND REACHING WESTERN
PORTIONS OF MIDDLE TN TOWARD SUNRISE. HRRR FURTHER SUPPORTS AN
INCREASE IN OUR POPS OVERNIGHT FOR MAINLY OUR WESTERN AREAS.
THUS...WILL GO AHEAD AND MODIFY THE WEATHER GRIDS AND SEPARATE THE
OVERNIGHT GRIDS INTO TWO...00Z-06Z AND 06Z-12Z. WILL EXPAND THE LIKELY
POPS OVER OUR WEST AND MOVE THE CHC CATEGORY A LITTLE FURTHER EAST
AS WELL.

REMAINDER OF FCST IS IN GOOD SHAPE. SEE NO REASON FOR ANY FURTHER
MODS. UPDATES OUT SHORTLY.

PREV DISCUSSION.../ISSUED 312 PM CDT THU MAY 16 2013/

SHORT TERM...RIDGE OF HIGH PRESSURE SITUATED EAST OF MIDDLE
TENNESSEE THIS AFTERNOON, ALLOWING ADVECTION OF WARM, MOIST AIR TO
TAKE PLACE. LATEST LAPS SOUNDING SHOWS INSTABILITY GRADUALLY
INCREASING WITH AFTERNOON HEATING, BUT ATMOSPHERE BELOW 600 MB IS
STILL LARGELY DRY. LOOK FOR SATURATION TO GRADUALLY TAKE PLACE
LATER TONIGHT AS TOMORROW S A SHORTWAVE APPROACHES MIDDLE
TENNESSEE FROM THE WEST AND BEGINS TO SPREAD CONVECTION ACROSS THE
MID STATE. LOOK FOR MAINLY SCATTERED ACTIVITY WEST OF THE PLATEAU
OVERNIGHT, WITH POP`S INCREASING TOMORROW.

CENTER OF UPPER LOW MOVES INTO SOUTHWESTERN KENTUCKY BY TOMORROW
AFTERNOON ACCOMPANIED BY A GOOD BAND OF LIFT OVER OUR WESTERN
COUNTIES. THUS, HAVE GONE WITH CATEGORICAL POPS FOR THOSE AREAS
TOMORROW, RANGING TO 50% POPS ALONG THE UPPER CUMBERLAND.

SHORTWAVE CONTINUES SLOWLY EASTWARD FRIDAY NIGHT, WITH SHOWERS
AND THUNDERSTORMS LIKELY AREA-WIDE. ATMOSPHERIC MOISTURE REMAINS
DEEP ON SATURDAY, ESPECIALLY NORTH AND EAST, WHERE SHOWERS AND
THUNDERSTORMS WILL REMAIN LIKELY.

WESTERN AREAS SHOULD START TO DRY OUT BY LATE SATURDAY NIGHT, AS
UPPER LOW CENTER MOVES TO NEAR SOUTHWEST VIRGINIA BY 12Z SUNDAY.

RIDGE OF HIGH PRESSURE BUILDS IN OVER THE AREA EARLY NEXT WEEK,
ALLOWING FOR MORE DAYTIME SUNSHINE AND SENDING DAYTIME HIGHS
PUSHING INTO THE MIDDLE AND UPPER 80S BOTH MONDAY AND TUESDAY.

LONG TERM...DURING THE MIDDLE TO LATTER PART OF NEXT WEEK, EXPECT
UPPER RIDGE TO PUSH EAST, ALLOWING FOR A MOIST SOUTHWEST FLOW TO
DEVELOP FROM THE SOUTHERN PLAINS AND LOWER MISSISSIPPI RIVER VALLEY
UP ACROSS THE TENNESSEE AND OHIO RIVER VALLEYS. SHOWERS AND
THUNDERSTORMS WILL PROBABLY BECOME LIKELY AGAIN BY WEDNESDAY, WITH
AT LEAST SMALL CHANCES FOR SHOWERS AND THUNDERSTORMS LINGERING
INTO THURSDAY AS WELL.
&&

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

$$
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