Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 050449
AFDLMK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
1249 AM EDT WED AUG 5 2015

...FORECAST UPDATE...
ISSUED AT 1245 AM EDT WED AUG 5 2015

UPDATED THE FORECAST TO GET RID OF AFTERNOON WORDING AND REFRESH TO
CURRENT TEMPS/DEWPTS/PRECIP.  THE MAJORITY OF THE OVERNIGHT HOURS
LOOK DRY ALTHOUGH WE SHOULD SEE RE-DEVELOPMENT OF CONVECTION TOWARD
SUNRISE AS THE LOW LEVEL JET RAMPS UP TO OUR WEST INCREASING
ISENTROPIC LIFT. THE CURRENT FORECAST HANDLES THIS WELL.  DID ADD
MORE PATCHY FOG THROUGH THE OVERNIGHT HOURS AS MANY PLACES WILL SEE
LIGHT GROUND FOG OVERNIGHT IN THE WAKE OF EVENING RAINS.

ISSUED AT 953 PM EDT TUE AUG 4 2015

CONVECTION CONTINUES TO DIE THIS EVENING WITH THE LOSS OF DAYTIME
HEATING.  EXPECT THIS TREND TO CONTINUE INTO THE OVERNIGHT HOURS.
UNCERTAINTY REMAINS RATHER HIGH ON WHAT WILL OCCUR EARLY WEDNESDAY
MORNING...AS THE GUIDANCE SUITE IS STRUGGLING WITH ONGOING
CONVECTION LEADING LITTLE CONFIDENCE TO THEIR SOLUTIONS FOR TONIGHT.
THAT BEING SAID...THE 04/23Z HRRR SEEMS TO HAVE THE BEST HANDLE OF
THE ONGOING SITUATION SO WILL LEAN ON THAT FOR THE OVERNIGHT HOURS.
THIS SOLUTION KEEPS MUCH OF THE OVERNIGHT DRY...SO WILL TREND THE
FORECAST THAT WAY.  THE SYNOPTIC MODELS ARE TRYING TO HINT AT
ISENTROPIC ASCENT PICKING UP TOWARDS DAWN WEDNESDAY...BUT SEEING
VERY LITTLE HINTS OF THAT OCCURRING TO THE WEST CURRENTLY.
THEREFORE...WILL TREND DRIER BUT WILL STILL KEEP POPS IN MAINLY
ACROSS SOUTH-CENTRAL KENTUCKY WEDNESDAY MORNING.

.SHORT TERM (NOW THROUGH THURSDAY NIGHT)...
ISSUED AT 315 PM EDT TUE AUG 4 2015

SCATTERED SHOWERS AND STORMS HAVE DEVELOPED ON A DIFFERENTIAL
HEATING AND DEW POINT BOUNDARY ACROSS CENTRAL AND SOUTH CENTRAL KY.
THE SLOW MOVING NATURE OF THESE STORMS MAY PUT DOWN SOME HEAVY
RAINFALL IN SPOTS. A FEW STRONGER STORMS ARE POSSIBLE GIVEN THE
AMOUNT OF INSTABILITY, ALTHOUGH OVERALL ORGANIZATION IS NOT EXPECTED
DUE TO THE LACK OF STRONGER DEEP LAYER SHEAR. SHOWERS/STORMS WILL
PUSH OFF TO THE EAST THROUGH THE EARLY EVENING HOURS, BEFORE A
RELATIVE LULL THROUGH THE OVERNIGHT. CAN`T RULE OUT A FEW SHOWERS
DROPPING IN FROM THE NW, SO WILL LEAVE SMALL CHANCES IN THROUGH THE
OVERNIGHT. LOOK FOR LOWS IN THE UPPER 60S NE TO LOW 70S SW.

DO EXPECT TO SEE ISOLATED TO WIDELY SCATTERED SHOWER/STORM ACTIVITY
MAINLY CONFINDED TO OUR WESTERN CWA ROUGHLY ALONG THE STALLED
BOUNDARY THAT WILL BE IN PLACE. EXPECT MOST HIGHS TO BE IN THE UPPER
80S.

...FLASH FLOOD WATCH LATE WEDNESDAY EVENING THROUGH EARLY FRIDAY...

AS WE ENTER LATER WEDNESDAY AFTERNOON AND EVENING A SLOW MOVING
UPPER WAVE AND ASSOCIATED SURFACE LOW WILL MOVE INTO THE MISSISSIPPI
RIVER VALLEY AND THEN LOWER OHIO RIVER VALLEY. AS THIS OCCURS DEEPER
MOISTURE WILL BE TRANSPORTED IN THROUGH A DEEP LAYER, PARTICULARLY
OF NOTE WILL BE A 40 KNOT LOW LEVEL JET. PRECIPITABLE WATER AMOUNTS
WILL RANGE IN THE 2 - 2.5 RANGE FROM LATE WEDNESDAY NIGHT THROUGH
THURSDAY AS THE SLOW MOVING SYSTEM MOVES THROUGH. SOME AREAS WILL
LIKELY SEE REPEATED ROUNDS OF HEAVY RAINFALL. DURING THIS TIME, 1.5
TO 2 INCHES OF RAIN IS EXPECTED WITH LOCALLY HIGHER AMOUNTS POSSIBLE
ACROSS SOUTHERN IN AND NORTH CENTRAL KY. GIVEN THE METEOROLOGICAL
SETUP, RECENT HEAVY RAINFALL IN SPOTS, AND A WPC SLIGHT RISK OF
EXCESSIVE RAINFALL ELECTED TO ISSUE A FLASH FLOOD WATCH IN
COORDINATION WITH JKL FROM LATER WEDNESDAY EVENING THROUGH EARLY
FRIDAY MORNING ACROSS THE NORTHERN TWO-THIRDS OF THE CWA. AT THIS
POINT, EXPECT THE HEAVIEST AXIS OF RAIN TO FALL ALONG AND ON EITHER
SIDE OF THE I-64 CORRIDOR.

THE SYSTEM SLIDES EAST BY THURSDAY NIGHT WITH PRECIPITATION ENDING
FROM WEST TO EAST. FLASH FLOOD WATCH IS SET TO EXPIRE AT 2 AM EDT/1
AM CDT.

.LONG TERM (FRIDAY THROUGH WEDNESDAY)...
ISSUED AT 325 PM EDT TUE AUG 4 2015

MID LEVEL VORTICITY MAXIMUM WILL PUSH ON OFF TO THE EAST ON FRIDAY
AND IN ITS WAKE, A BIT OF MID-LEVEL RIDGING WILL BUILD IN FROM THE
WEST.  THIS SHOULD GIVE US A TEMPORARY BREAK FROM THE RAINS FROM
MIDWEEK.  HOWEVER, THIS DRY TREND WILL NOT LAST ALL THAT LONG.  THE
LATEST FORECASTS SUGGEST THAT A MID-LEVEL RIDGE AXIS WILL SET BACK
UP ACROSS TEXAS BY THE LATE PART OF THE WEEKEND AND INTO EARLY NEXT
WEEK.  THE UPPER LEVEL RIDGE IS EXPECTED TO BE MORE FLAT, THUS, THE
OHIO VALLEY WILL REMAIN ON THE PERIPHERY OF THE RIDGE AXIS SETTING
THE STAGE FOR MORE UNSETTLED WEATHER AS MID-LEVEL VORT MAXES ROUND
THE TOP OF THE RIDGE.

WHILE FORECAST CONFIDENCE IS LOW REGARDING THE TIMING OF THE WAVES
IN THE LATE PART OF THE PERIOD, IT DOES APPEAR THAT SEVERAL WILL
IMPACT THE REGION FROM LATE SATURDAY NIGHT THROUGH TUESDAY.  THE
FIRST MAY AFFECT OUR REGION LATE SATURDAY NIGHT, FOLLOWED BY ANOTHER
ONE ON MONDAY.  THE PATTERN IS ONE THAT FAVORS ONE OR MORE MESOSCALE
CONVECTIVE COMPLEXES DEVELOPING AND THEN RACING FROM THE CENTRAL
PLAINS THROUGH THE OHIO VALLEY.  IT IS REALLY NOT ALL THAT
SURPRISING GIVEN THIS PATTERN HAS BEEN SEEN IN RECENT WEEKS.  THE
THREAT OF ADDITIONAL HEAVY RAINFALL IS CERTAINLY THERE, AND WE MAY
SEE ADDITIONAL HYDRO ISSUES IN SOME PARTS OF THE AREA EARLY NEXT
WEEK, DEPENDING ON WHERE THE EVENTUAL MCS TRACK SETS UP.

TEMPERATURES WILL START OFF BELOW NORMAL FOR THE PERIOD WITH LOW-MID
80S ACROSS THE REGION ON FRIDAY.  A BRIEF MODERATION IN TEMPS LOOKS
LIKELY FOR SATURDAY AND SUNDAY WITH HIGHS IN THE MID 80S NORTH AND
MID-UPPER 80S IN THE SOUTH.  LOW TO MID 80S LOOK LIKELY FOR MONDAY
AND TUESDAY AS WELL, GIVEN THAT WE`RE EXPECTING CLOUDS AND
PRECIPITATION TO BE IN THE AREA.  IF CONVECTIVE COVERAGE IS LESS,
THEN TEMPERATURES MAY NEED TO BE INCREASED SLIGHTLY IN SUBSEQUENT
FORECASTS.  OVERNIGHT LOWS DURING THE PERIOD WILL BE IN THE UPPER
60S TO THE LOWER 70S.

&&

.AVIATION (00Z TAF UPDATE)...
ISSUED AT 744 PM EDT TUE AUG 4 2015

A LINE OF THUNDERSTORMS PACKING STRONG WINDS AND IFR VSBYS WILL PASS
THROUGH KSDF AT THE START OF THE PERIOD.  THIS LINE MAY PERSIST EAST
INTO LEXINGTON...BUT WILL SEE HOW THINGS PROGRESS BEFORE ADDING MORE
THAN VCTS AT THIS TIME.  AFTER THIS LINE MOVES THROUGH...CONFIDENCE
LOWERS QUITE A BIT IN WHAT MAY OCCUR OVERNIGHT.  THE LATEST HI-RES
GUIDANCE SUITE SUGGESTS ACTIVITY WILL STRUGGLE TO GET GOING
OVERNIGHT...SO HAVE PLAYED DOWN THUNDERSTORM CHANCES AFTER THIS
INITIAL LINE MOVES THROUGH.  THAT BEING SAID...CANNOT RULE OUT
CONVECTION FIRING ACROSS MISSOURI AND WESTERN KENTUCKY
TONIGHT...GETTING INTO KSDF OR KBWG EARLY WEDNESDAY MORNING. IF
CONVECTION DOES NOT REDEVELOP OVERNIGHT...THEN SOME LIGHT FOG WILL
BE POSSIBLE AT KWBG OR KLEX.

WEDNESDAY WILL ALL DEPEND ON HOW CONVECTION PLAYS OUT
OVERNIGHT...BUT ADDITIONAL THUNDERSTORMS WILL BE POSSIBLE TOWARD THE
END OF THE PERIOD AS ANOTHER SYSTEM APPROACHES FROM THE WEST.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...FLASH FLOOD WATCH FROM THIS EVENING THROUGH LATE THURSDAY NIGHT
     FOR KYZ023>043-045>049-053>057-063>067.

IN...FLASH FLOOD WATCH FROM THIS EVENING THROUGH LATE THURSDAY NIGHT
     FOR INZ076>079-083-084-089>092.

&&

$$

UPDATE.........KJD/AMS
SHORT TERM.....BJS
LONG TERM......MJ
AVIATION.......KJD



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