Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 040706
AFDLMK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
306 AM EDT TUE AUG 4 2015

.SHORT TERM (NOW THROUGH WEDNESDAY)...
ISSUED AT 300 AM EDT TUE AUG 4 2015

AN EARLY MORNING SURFACE ANALYSIS SHOWED WEAK HIGH PRESSURE OVER THE
GREAT LAKES INTO THE LOWER OHIO VALLEY REGION. A REFLECTION OF
YESTERDAY`S SURFACE FRONT / OUTFLOW BOUNDARY EXISTED FROM EASTERN TO
SOUTH CENTRAL KENTUCKY. A DEWPOINT ANALYSIS INDICATED SLIGHTLY DRIER
AIR HAD FILTERED IN SOUTHERN INDIANA...NOTED BY READINGS IN THE MID
60S COMPARED TO LOW/MID 70S CLOSER TO THE TN BORDER. ALOFT...WATER
VAPOR IMAGERY AND 500 MB HEIGHTS SHOWED THE PERSISTENT RIDGE WEST
/ TROUGH EAST PATTERN. SHORTWAVE TROUGHS WERE NOTED COMING OFF THE
CENTRAL ROCKIES...THROUGH THE CENTRAL PLAINS AND TN/OH VALLEYS.
EARLY MORNING READINGS WERE IN THE LOW/MID 70S WITH LIGHT/VARIABLE
WINDS AND MOSTLY CLEAR SKIES.

FOR TODAY...04.00Z GUIDANCE AND HI-RES MODELS ARE IN REASONABLE
AGREEMENT ACROSS SOUTHERN INDIANA AND CENTRAL KENTUCKY. THE
STALLED/WASHED OUT SURFACE FRONT WILL REMAIN DRAPED ACROSS THE AREA
BUT THE LACK OF ANY STRONG UPPER LEVEL TRIGGER WILL LIKELY KEEP
STORM DEVELOPMENT IN THE ISOLATED TO WIDELY SCATTERED RANGE. PLAN ON
HIGHS IN THE MID/UPPER 80S TO NEAR 90 AND WINDS 5-10 MPH OUT OF THE
WEST.

WHATEVER CONVECTION THAT DOES MANAGE TO DEVELOP TODAY WOULD BE
DIURNAL IN NATURE...SO TAPERED PRECIPITATION CHANCES DOWNWARD
THROUGH THE EVENING. LOOK FOR ANOTHER MILD NIGHT WITH LOWS IN THE
70S. WHERE WINDS SLACKEN OFF AND GIVEN SOME RESIDUAL MOISTURE IN
PLAY...THERE COULD BE SOME LIGHT PATCHY FOG IN THE FAVORED AREAS.

FOR WEDNESDAY...A TIME TREND ANALYSIS SHOWS THAT MODEL GUIDANCE IS
TRENDING SLOWER AND WEAKER WITH THE NEXT SHORTWAVE TROUGH COMING IN
FROM THE WEST. THE WAVE DAMPENS OUT CONSIDERABLY AS IT NEARS WESTERN
KENTUCKY. THE LIMITED FORCING COULD MAKE FOR A LESSER COVERAGE OF
STORMS THAN INITIALLY ANTICIPATED...SO HAVE CONTINUED THE TREND OF
LOWERING POPS TO MORE OF THE ISOLATED/SCATTERED RANGE OR 30 TO 50
PERCENT. AS A RESULT...NUDGED UP HIGHS A COUPLE DEGREES INTO THE 88-
93 DEGREE RANGE.

.LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)...
ISSUED AT 300 AM EDT TUE AUG 4 2015

WED NIGHT - THURS NIGHT...

A SFC FRONT WILL SLOWLY MOVE NORTH THROUGH THE OHIO VALLEY WED NIGHT
THROUGH THURS NIGHT WHILE ONE OR TWO UPPER LEVEL SHORTWAVES MOVE
THROUGH THE REGION AS WELL.  THIS WILL CAUSE NUMEROUS SHOWERS/STORMS
WED NIGHT THROUGH THURS NIGHT.  WITH A VERY MOIST SOUNDING PROFILE
AND PRECIPITABLE WATER VALUES BETWEEN 2-2.25 INCHES ESPECIALLY
DURING THE DAY ON THURSDAY, HEAVY RAINFALL AND POTENTIAL FLOODING
WILL BE THE GREATEST THREAT FROM MID WEEK CONVECTION.  MODELS VARY
ON HOW QUICKLY PRECIPITATION WILL MOVE EAST OF THE AREA THURS NIGHT.
WILL CONTINUE THE DRIER SOLN SIMILAR TO THE ECMWF/NAM.

TEMPERATURES WILL RANGE THROUGH THE 60S AND LOW 70S FOR LOWS.  HIGHS
WILL BE LIMITED TO THE UPPER 70S AND LOWER 80S FOR THURS AS CLOUD
COVER AND PRECIP LIMIT DIURNAL HEATING.

FRIDAY - MONDAY...

FRIDAY MID RANGE MODELS VARY ON IF ANOTHER SIGNIFICANT UPPER LEVEL
SHORTWAVE WILL DROP INTO THE OHIO VALLEY OR IF IT WILL STAY TO THE
NORTH LEAVING OUR REGION MAINLY DRY.  IF THE WETTER GFS SOLN PLAYS
OUT...AN EXTENDED RAINY PERIOD MAY START WED NIGHT AND CONTINUE
THROUGH FRIDAY NIGHT.  THIS SCENARIO WOULD LIKELY RESULT IN SOME
MINOR FLOODING.  HOWEVER...THE ECMWF REMAINS LARGELY DRY THURS NIGHT
THROUGH FRIDAY STILL.  AT THIS POINT...WILL CONTINUE A MIDDLE OF
THE ROAD APPROACH LEAVING 20-30% POPS IN FOR THE END OF THE WEEK.

SAT/SUN SHOULD BE PRIMARILY DRY BEFORE AN ACTIVE PATTERN BRINGS MORE
STORMS CLUSTERS FOR THE BEGINNING OF NEXT WEEK.  HIGHS WILL LARGELY
REMAIN IN THE 80S FRI-MON WITH LOWS IN THE 60S TO AROUND 70.

&&

.AVIATION (06Z TAF UPDATE)...
ISSUED AT 1250 AM EDT TUE AUG 4 2015

LIGHT/VARIABLE WINDS AND MOISTURE POOL ALONG STALLING SURFACE FRONT
AND CONVECTIVE OUTFLOW BOUNDARIES MAY ALLOW LIGHT FOG TO DEVELOP AT
BWG AND LEX DURING THE PRE-DAWN HOURS. FOR THE REMAINDER OF
TODAY...VFR CONDITIONS EXPECTED AT ALL SITES WITH WINDS AT OR BELOW
10 KTS. DURING PEAK HEATING THIS AFTERNOON...AN APPROACHING WEATHER
SYSTEM AND INTERACTION WITH THE AFOREMENTIONED SURFACE BOUNDARIES
MAY RESULT IN ISOLATED TO WIDELY SCATTERED SHOWERS/STORMS.
HOWEVER...ENVIRONMENT IS NOT SUPPORTIVE OF HIGH COVERAGE SO WILL
LEAVE OUT OF TAF AT THIS POINT. PLAN ON LIGHT/VARIABLE WINDS AGAIN
TONIGHT...WITH INCREASING HIGH CLOUDS FROM THE WEST BY THE END OF
THE PERIOD.

&&

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

$$

SHORT TERM........ZT
LONG TERM.........AMS
AVIATION..........ZT


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