Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 050455
AFDLMK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
1255 AM EDT SAT SEP 5 2015

...UPDATED AVIATION DISCUSSION...

...FORECAST UPDATE...
ISSUED AT 910 PM EDT FRI SEP 4 2015

UPDATED THE FORECAST TO EXTEND POPS OVER SOUTHEAST INDIANA AND THE
NORTHERN BLUEGRASS THROUGH 3-4Z.  A STRONG OUTFLOW BOUNDARY FROM THE
CENTRAL INDIANA/SOUTHERN OHIO COMPLEX OF STORMS HAS PUSHED SOUTHWEST
INTO OUR AREA AND HAS SPURRED RENEWED CONVECTION MAINLY OVER
JEFFERSON COUNTY INDIANA.  THIS OUTFLOW WILL CONTINUE TO PUSH
SOUTHWEST AND MAY CONTINUE TO STIR UP SOME CONVECTION, HOWEVER, IN
THE VERY LATEST RADAR SCANS IT SEEMS TO BE LESS EFFICIENT IN
CREATING NEW STORMS PROBABLY SINCE THE IT`S BECOMING WEAKER AS IT
BECOMES MORE DISPLACED FROM IT`S PARENT COMPLEX AND BECAUSE THE
ENVIRONMENT ISN`T QUITE AS FAVORABLE FOR NEW STORM DEVELOPMENT.
STILL EXPECT THE GUST FRONT ITSELF TO CONTINUE TO PUSH SOUTHWEST
PRODUCING WIND GUSTS IN THE 30-40 MPH RANGE (AS REPORTED IN
MADISON, IN) FOR ANOTHER 1-3 HRS THIS EVENING.

ALSO ADDED PATCHY FOG OVER THE ENTIRE AREA FOR LATE TONIGHT.  THINK
THAT PATCHY LIGHT FOG WILL BE QUITE COMMON IN THE REGION LIKE LAST
NIGHT.

ISSUED AT 500 PM EDT FRI SEP 4 2015

UPDATED THE FORECAST TO INCLUDE A 20% CHANCE OF AN ISLD SHOWER/STORM
FOR MUCH OF THE AREA THROUGH THIS EVENING.  A FEW SHOWERS/STORMS
HAVE POPPED UP ON RADAR OVER THE LAST HOUR AND SHOULD PERSIST
THROUGH THIS EVENING BEFORE FIZZLING.

.SHORT TERM (NOW THROUGH SATURDAY NIGHT)...
ISSUED AT 230 PM EDT FRI SEP 4 2015

BROAD BUT WEAK SURFACE HIGH PRESSURE OVER THE OHIO VALLEY, WITH
UPPER RIDGING JUST TO OUR WEST, WILL MAINTAIN A STAGNANT WEATHER
PATTERN INTO THE HOLIDAY WEEKEND. THE FLOW ALOFT IS QUITE WEAK OUT
OF THE NW, BUT FORCING FOR ANY ORGANIZED PRECIP REMAINS WELL TO OUR
NORTH AND EAST. GIVEN THE ISOLATED AFTERNOON CONVECTION OF THE LAST
FEW DAYS, STILL CAN`T RULE OUT A POP-UP SHOWER OR THUNDERSTORM,
ESPECIALLY OVER THE BLUEGRASS REGION WHERE HEIGHTS ARE SLIGHTLY
LOWER.

MODELS CONTINUE TO ADVERTISE SUBTLE HEIGHT RISES ON SATURDAY, BUT WE
HAVE SEEN THAT DAILY IN THIS PATTERN WITH LITTLE CHANGE IN SENSIBLE
WX. THEREFORE IT REMAINS A PERSISTENCE FORECAST, RIGHT DOWN TO THE
VALLEY FOG OVERNIGHT AND THE MORNING HAZE. TEMPS MAY EDGE UP ANOTHER
DEGREE IN SOME LOCATIONS, KEEPING THE DOOR OPEN FOR THE WARMEST
TEMPS OF THE YEAR.

.LONG TERM (SUNDAY THROUGH FRIDAY)...
ISSUED AT 225 PM EDT FRI SEP 4 2015

THE MAIN FOCUS IN THE LONG TERM FORECAST PERIOD IS THE CONTINUATION
OF THE UNSEASONABLY WARM TO HOT CONDITIONS...THEN SHOWER AND STORM
CHANCES THE MIDDLE OF NEXT WEEK THAT WILL BRING RELIEF FROM THE HEAT
AND HUMIDITY TO THE AREA.

OVERALL...THE SYNOPTIC PATTERN WILL REMAIN UNCHANGED SUNDAY THROUGH
TUESDAY AS UPPER LEVEL RIDGING DOMINATES OVER THE LOWER OHIO VALLEY
AND SOUTHEAST US. DAYTIME HIGHS LOOK TO TOP OUT IN THE UPPER 80S TO
LOW 90S...WITH MID 90S POSSIBLE IN THE TYPICAL WARM SPOTS AND URBAN
CORES. A WEAK MID LEVEL CAP...SUBSIDENCE ALOFT AND THE LACK OF A
REAL FORCING MECHANISM WILL CONTINUE TO KEEP THE FORECAST DRY FOR
THE AREA. PLAN ON MILD TO MUGGY NIGHTS...WITH PATCHY MORNING
FOG/HAZE IN THE TYPICAL FAVORED SPOTS.

04.12Z GUIDANCE FOLLOWED PREVIOUS MODEL CYCLES IN A SLOWING TREND
WITH THE NEXT WEATHER SYSTEM AND COLD FRONTAL PASSAGE. BASED ON THE
ENSEMBLE SPREAD AND DETERMINISTIC GUIDANCE...SHOWER AND STORM
CHANCES WILL RETURN TO THE FORECAST WEDNESDAY...THOUGH THE HIGHEST
CHANCES AT THIS TIME LOOK TO BE WEDNESDAY NIGHT THROUGH THURSDAY
AFTERNOON AS THE FRONT PASSES. AT THIS TIME...SEVERE CHANCES LOOK
LOW BASED ON VERY WEAK SHEAR PROFILES AND AN UNFAVORABLE TIME OF
DAY.

ONCE THE FRONT CLEARS THE REGION...A STRONG PUSH OF DRIER AND COOLER
AIR IS LOOKING LIKELY AND SHOULD SEND READINGS TO NEAR NORMAL OR
SLIGHTLY BELOW NORMAL LEVELS. A MODEL CONSENSUS OF HIGHS IN THE
UPPER 70S TO LOW 80S WITH LOWS IN THE LOW 60S LOOKS GOOD FOR NOW.

&&

.AVIATION (06Z TAF UPDATE)...
ISSUED AT 1254 AM EDT SAT SEP 5 2015

EARLIER CONVECTION TO THE NORTHEAST BROUGHT AN OUTFLOW BOUNDARY
THROUGH KSDF AND KLEX THIS EVENING.  BEHIND THIS
BOUNDARY...DEWPOINTS HAVE COME DOWN A BIT WHICH MAY HELP TO LIMIT
FOG/HZ POTENTIAL.  HAVE KEPT IN MVFR RESTRICTIONS...BUT STARTED THEM
A BIT LATER THAN THE PREVIOUS FORECAST.  THE BOUNDARY MAY HELP LIMIT
KBWG FOG POTENTIAL AS WELL...BUT WITH THE BOUNDARY LIKELY WASHING
OUT SOMEWHERE NEAR THE TERMINAL...DO NOT HAVE THE CONFIDENCE TO
DOWNPLAY FOG POTENTIAL JUST YET.  WILL LEAVE IN A TEMPO IFR GROUP.

OTHERWISE TODAY WILL BE MORE OF THE SAME...WITH ANY FOG/HZ QUICKLY
BURNING OFF AND DIURNAL CU DEVELOPING IN THE AFTERNOON.  A FEW
ISOLATED STORMS WILL BE POSSIBLE ONCE AGAIN...BUT COVERAGE TOO LOW
TO WARRANT MENTION IN THE TAFS.  WINDS WILL BE OUT OF THE ESE AT 5-
10 KNOTS.

&&

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

$$

UPDATE.........AMS
SHORT TERM.....RAS
LONG TERM......ZBT
AVIATION.......KJD



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