Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 290706
AFDLMK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
306 AM EDT SAT AUG 29 2015

.SHORT TERM (NOW THROUGH SUNDAY)...
ISSUED AT 235 AM EDT SAT AUG 29 2015

EARLY MORNING WATER VAPOR IMAGERY COMBINED WITH 500 MB HEIGHTS
SHOWED A MID LEVEL TROUGH EXTENDING FROM THE CENTRAL PLAINS
NORTHEASTWARD TOWARD EASTERN WISCONSIN...WHILE A BROAD CLOSED LOW
WAS ADVANCING NORTHWARD FROM THE GULF INTO THE DEEP SOUTH. THE
LOWER OHIO VALLEY LIED IN BETWEEN...AS OBSERVED BY IR SATELLITE
IMAGERY WHICH SHOWED MOSTLY CLEAR SKIES AND LIGHT WINDS. DEEPER
MOISTURE...CLOUDY SKIES...AND LIGHT RADAR RETURNS WERE OFF TO THE
NORTHWEST.

THE MAIN FORECAST CONCERN FOR TODAY IS PRECIPITATION CHANCES AS THE
TWO AFOREMENTIONED SYSTEMS TRACK TOWARD EACH OTHER. THE SOUTHERN
SYSTEM WILL DRAW MORE MOISTURE INTO THE AREA...CHARACTERIZED BY
DEWPOINTS APPROACHING THE UPPER 60S TO NEAR 70 THIS AFTERNOON. THE
NORTHERN SYSTEM WILL BEGIN TO WASH OUT AS IT SLOWLY ADVANCES
EASTWARD. OVERALL...DYNAMICS ARE RATHER WEAK WITH THESE SYSTEMS BUT
A WEAKLY OR UNCAPPED ENVIRONMENT ALONG WITH PEAK HEATING GENERATING
POCKETS OF INSTABILITY SHOULD BREAK OUT ISOLATED TO SCATTERED NON
SEVERE SHOWERS AND STORMS.

NEAR TERM HI-RES MODELS SHOW HIGH AGREEMENT SPATIALLY...TEMPORALLY
AND RUN TO RUN WHICH LEADS TO A HIGHER CONFIDENCE FORECAST FOR
TODAY. THE HRRR HAS BEEN VERY CONSISTENT SHOWING ISOLATED
SHOWERS/STORMS BREAKING OUT DURING THE EARLY AFTERNOON HOURS AS
CONVECTIVE TEMPS ARE REACHED. THE NSSL AND SPC WRF SOLUTIONS OFFER
SIMILAR SOLUTIONS AS WELL. THE HIGHEST COVERAGE LOOKS TO BE ALONG A
BOWLING GREEN TO FRANKFORT LINE AND WESTWARD...ALONG THE AXIS OF
GREATER INSTABILITY AND MOISTURE.

MOSTLY SUNNY SKIES THIS MORNING WILL BE REPLACED BY SCATTERED
CUMULUS AS WELL AS MID/HIGH CLOUDS...WHICH SHOULD MAKE FOR A PARTLY
TO MOSTLY CLOUDY AFTERNOON AT TIMES. PLAN ON HIGHS TO TOP OUT IN THE
MID TO UPPER 80S. THE INCREASE IN DEWPOINTS WILL MAKE IT FEEL
SLIGHTLY MORE MUGGY THAN RECENT DAYS.

EXPECTING A DROP OFF IN PRECIPITATION THIS EVENING WITH THE LOSS OF
HEATING...THOUGH WILL STILL CARRY A CHANCE THROUGH THE OVERNIGHT
WITH THE WEAK TROUGH OVERHEAD. SUNDAY STILL LOOKS TO BE THE BETTER
DAY FOR PRECIPITATION AS WE`LL HAVE A MORE FAVORABLE ENVIRONMENT AND
OVERALL DYNAMICS. PRECIPITATION COVERAGE STILL LOOKS TO BE
SCATTERED...SO KEPT CHANCES IN THE 30-40 PERCENT RANGE.

.LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)...
ISSUED AT 300 AM EDT SAT AUG 29 2015

MONDAY - WEDNESDAY...

A WEAK UPPER LOW NEAR THE OHIO VALLEY MAY PROVIDE ENOUGH SUPPORT FOR
ISLD SHOWERS/STORMS MAINLY ALONG AND EAST OF I-65 SUNDAY NIGHT AND
MONDAY.  THE GFS IS MOST OPTIMISTIC WITH THIS CONVECTION AND EVEN
THIS NOTORIOUSLY WET MODEL ISN`T SHOWING MUCH PRECIP.

TUESDAY LOOKS TO BE DRY WITH THE NEXT CHANCE FOR SHOWERS/STORMS
ARRIVING FOR WED.  MID RANGE MODELS ARE DIFFERENT IN DEPICTING THE
MAIN SOURCE FOR FORCING/MOISTURE.  THE GFS INDICATES THE REMNANTS OF
T.S. ERIKA WILL BE THE CAUSE WHILE THE ECMWF SUGGESTS A NORTHERN
STREAM TROUGH WILL BE THE CAUSE.  EITHER WAY WILL CARRY 20-30% POPS
FOR WED.

TEMPS FOR EARLY TO MID WEEK WILL BE ON THE INCREASE BACK TO SEASONAL
NORMS WITH HIGHS RANGING MAINLY THE MID TO UPPER 80S WITH A FEW
LOCATIONS NEAR 90 TUES/WED.

THURSDAY - FRIDAY...

LONG RANGE MODELS AGREE THAT A STRONG UPPER RIDGE AXIS WILL BUILD
INTO PORTIONS OF THE PLAINS/MIDWEST.  THICKNESSES WILL INCREASE OVER
THE OHIO VALLEY AS A RESULT BRINGING TEMPS SLIGHTLY ABOVE NORMAL FOR
THE LATTER HALF OF THE WEEK (UPPER 80S/LOWER 90S FOR HIGHS).
ALTHOUGH A CLEAR TRIGGER IS NOT APPARENT, SOME LONG RANGE SIGNALS
SUGGEST A DIRTY RIDGE WITH SUBTLE WAVES MAY CAUSE MAINLY DIURNAL
CONVECTION PEAKING DURING THE AFTERNOON/EVENING HOURS BOTH
THURS/FRI.  THUS WILL HAVE LOW POPS BOTH OF THESE DAYS.

&&

.AVIATION (06Z TAF UPDATE)...
ISSUED AT 104 AM EDT SAT AUG 29 2015

A LIGHT WIND COMBINED WITH PASSING HIGH CLOUDS SHOULD LIMIT FOG
POTENTIAL AT BWG/LEX THROUGH EARLY THIS MORNING. OTHERWISE...PLAN ON
VFR CONDITIONS AT ALL SITES AS SOUTHERLY WINDS DEVELOP BY MID-
MORNING ALONG WITH A SCATTERED CU FIELD WITH BASES 4-5 KFT. THERE
ARE SIGNALS FOR ISOLATED TO SCATTERED SHOWERS OR A STORM
DEVELOPING BY 17-18Z...LASTING THROUGH ABOUT 23-00Z.
THOUGH...EXPECTING LOW COVERAGE WHICH PRECLUDES MENTIONING IN THE
TAF FOR NOW. WINDS WILL REMAIN SOUTHERLY THROUGH THE END OF THE
TAF PERIOD WITH PASSING SCATTERED/BROKEN HIGH CLOUDS.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&

$$

SHORT TERM........ZBT
LONG TERM.........AMS
AVIATION..........ZBT



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