664
FXUS63 KLMK 210436
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
1136 PM EST FRI NOV 20 2009
..UPDATED AVIATION DISCUSSION
SHORT TERM (TONIGHT AND SATURDAY)
MAIN QUESTION FOR TONIGHT AND SATURDAY REVOLVES AROUND PATCHY FOG
POSSIBILITIES LATE TONIGHT.
UPPER AIR PATTERN IS IN SOMEWHAT OF A SPLIT FLOW PATTERN OVER THE
CONUS. A BROAD ZONAL SOUTHERN JET CONTINUES JUST SOUTH OF OUR BORDER
AND ACROSS THE GULF OF MEXICO. EMBEDDED WITHIN THIS SOUTHERN JET IS
A DISTURBANCE NOW ACROSS TEXAS THAT WILL SPREAD RAIN ACROSS THE
WESTERN GULF STATES TOMORROW. THE MORE ACTIVE NORTHERN JET WILL
FEATURE A VIGOROUS 500MB TROUGH APPROACHING THE GREAT BASIN THIS
EVENING AND ANOTHER TROUGH SCOOTING EAST ACROSS NEW ENGLAND.
THE LOWER OHIO VALLEY WILL REMAIN WITHIN A DRY AND TRANQUIL PATTERN
THROUGH AT LEAST SATURDAY. THE CENTER OF A BROAD SURFACE RIDGE WILL
CROSS THE COMMONWEALTH AND MOVE INTO OHIO SATURDAY AFTERNOON.
NEARLY CALM WINDS WILL CONTINUE THIS EVENING AND
OVERNIGHT...TRENDING TOWARDS LIGHT EASTERLY BY SATURDAY AFTERNOON.
WIDESPREAD DENSE FOG DEVELOPED EARLIER THIS MORNING ACROSS CENTRAL
INDIANA. THIS AREA OF FOG THEN MOVED SOUTH ACROSS SOUTHERN INDIANA
AND BASICALLY TOOK ALL MORNING TO BURN OFF. FOG ALSO DEVELOPED
ACROSS SOME RIVER VALLEYS ACROSS CENTRAL AND EASTERN KENTUCKY.
FEEL THAT PATCHY FOG IS AGAIN POSSIBLE EARLY SATURDAY ACROSS RIVER
VALLEYS AND OPEN FIELDS. HOWEVER DO FEEL THAT IT WILL NOT BE AS
WIDESPREAD AS YESTERDAY DUE TO A SLIGHTLY BETTER MIXED BOUNDARY LAYER
AND AN EXPECTED LIGHT EASTERLY BOUNDARY LAYER WIND TOWARDS EARLY
MORNING.
EXPECT MOSTLY CLEAR SKIES THIS EVENING AND OVERNIGHT. ALTHOUGH MANY
AREAS WILL SEE QUITE A BIT OF SUN SATURDAY...INCREASING HIGH LEVEL
CLOUDS LATE AND POSSIBLE AFTERNOON SCATTERED CU DEVELOPMENT WILL TIP
THE FORECAST TOWARDS PARTLY CLOUDY. HIGHS TOMORROW WILL BE SIMILAR
TO FRIDAY AFTERNOON'S.
LONG TERM (SATURDAY NIGHT - FRIDAY)
NO MAJOR CHANGES MADE TO THE LONG TERM FORECAST FOR THIS PACKAGE.
MODELS HAVE TRENDED BACK TO DRIER OVER THE LAST FEW RUNS REGARDING
THE LOW PRESSURE SYSTEM MOVING NORTHEAST OUT OF THE WESTERN GULF
COAST STATES ON SUNDAY. RIGHT NOW IT LOOKS LIKE THE BEST CHANCE FOR
PRECIPITATION WILL BE OVER THE LAKE CUMBERLAND AND POSSIBLY
BLUEGRASS REGIONS. WILL LEAVE IN A SLIGHT CHANCE FOR RAIN OVER THE
NORTHERN HALF OF THE FORECAST AREA AS ANY DEVIATION IN THE PATH OF
THIS SYSTEM WILL BRING RAINS FARTHER NORTH ACROSS THE AREA. RAIN
WILL BEGIN EARLY SUNDAY AND LINGER THROUGH THE EVENING AS THIS
SYSTEM PULLS OFF TO THE NORTHEAST.
MONDAY WILL BE DRY IN BETWEEN THE DEPARTING SOUTHERN SYSTEM AND A
COLD FRONT APPROACHING THE REGION FROM THE WEST. A COLD RAIN WILL
ACCOMPANY THIS SYSTEM AS IT MOVES THROUGH THE REGION ON TUESDAY. WE
MAY SEE A BREAK IN PRECIPITATION ON WEDNESDAY BEFORE ANOTHER WEAK
SYSTEM DIVING DOWN IN NORTHWEST FLOW ALOFT WILL CLIP MAINLY THE
NORTHERN HALF OF THE FORECAST AREA ON THURSDAY.
TEMPERATURES WILL BE A BIT ABOVE NORMAL THE FIRST HALF OF THE
FORECAST PERIOD WITH MONDAY LOOKING TO BE THE WARMEST DAY. HIGHS
OVER SOUTH CENTRAL KENTUCKY COULD TOP OUT AROUND 60 ON MONDAY. WITH
COOL NORTHWEST FLOW BEHIND THE COLD FRONT WEDNESDAY WILL BE AROUND
NORMAL IN THE LOWER TO MID 50S WHILE HIGHS AT THE END OF THE REACH
COULD STRUGGLE TO GET TO 50. LOWS WILL RANGE FROM THE MID 40S TO
LOWER 30S BY THE END OF THE WEEK.
AVIATION (06Z TAF ISSUANCE)
WEAK HIGH PRESSURE CENTERED OVER THE LOWER OHIO VALLEY WILL
GRADUALLY SHIFT TO THE NORTHEAST DURING THE NEXT 24 HOURS. THE MAIN
ISSUE FOR THIS PERIOD WILL AGAIN BE FOG FORMATION TOWARDS MORNING.
ALL MODELS SHOW A FAIRLY MOIST LOWER LEVEL SO WE EXPECT FOG
FORMATION AFTER 08Z. SDF AND LEX SHOULD REMAIN IN THE MVFR RANGE
WHILE BWG MAY BRIEFLY DROP TO IFR CONDITIONS. ONCE THE FOG
DISSIPATES AFTER 14Z VFR CONDITIONS ARE EXPECTED.
LMK WATCHES/WARNINGS/ADVISORIES
KY...NONE.
IN...NONE.
SHORT TERM........JSD
LONG TERM.........EES
AVIATION..........JA
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