FXUS63 KLMK 290534
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
1234 AM EST SUN NOV 29 2009
...UPDATED AVIATION DISCUSSION...
.SHORT TERM (TONIGHT AND SUNDAY)...
HIGH PRESSURE OVER THE SOUTHEAST STATES WILL CONTINUE TO INFLUENCE
THE AREA TONIGHT INTO SUNDAY MORNING. MOISTURE WILL ADVECT INTO THE
REGION AND AS SURFACE WINDS INCREASE FROM THE SOUTHWEST DURING THE
DAY SUNDAY. AN UPPER LEVEL TROUGH OVER THE UPPER MIDWEST WILL DIG
INTO THE MISSISSIPPI VALLEY AND A SURFACE LOW WILL BRING A COLD
FRONT TOWARD SOUTHERN INDIANA LATE SUNDAY AFTERNOON/EARLY EVENING.
THE OVERNIGHT HOURS TONIGHT AND MOST OF SUNDAY SHOULD REMAIN DRY
WITH SHOWERS MOVING INTO SOUTHERN INDIANA LATE IN THE DAY BEFORE
OVERSPREADING THE REGION SUNDAY NIGHT. MOST OF THE LATEST MODEL
GUIDANCE HAVE SLOWED DOWN THE ONSET OF PRECIPITATION WITH THE SREF
AND SPC WRF SHOWING SHOWERS MOVING INTO SOUTHERN INDIANA BY AROUND
21Z. HAVE ADJUSTED POPS ACCORDINGLY TO MATCH UP BETTER WITH THIS
TREND WITH THE BEST CHANCES OVER OUR INDIANA COUNTIES AND FAR NORTH
CENTRAL KENTUCKY BY 21Z-00Z.
OVERNIGHT LOWS WILL BE AROUND 10 TO 15 DEGREES WARMER AREAWIDE
TONIGHT UNDER A WARM AIR ADVECTION PATTERN WITH TEMPERATURES FALLING
INTO THE LOW 40S. HIGHS ON SUNDAY WILL RANGE FROM THE MID 50S IN THE
NORTHWEST TO AROUND 60 IN THE EAST.
.LONG TERM (SUNDAY NIGHT - SATURDAY)...
SUNDAY NIGHT THROUGH TUESDAY...
A QUICK MOVING NORTHERN STREAM UPPER LEVEL TROUGH WILL DROP OUT OF
MONTANA AND MOVE TOWARD THE GREAT LAKES. AT THE BEGINNING OF THIS
FORECAST PERIOD AN ASSOCIATED COLD FRONT WILL STRETCH SOUTHWEST FROM
AN AREA OF LOW PRESSURE OVER NORTHERN OHIO TO EXTREME WESTERN
KENTUCKY. GULF MOISTURE WILL BE STREAMING NORTH AHEAD OF THIS SYSTEM
AND WILL OVERSPREAD THE LOWER OHIO VALLEY.
PREVIOUS FORECASTS HAVE HANDLED THIS SYSTEM WELL AND FEW CHANGES
HAVE BEEN MADE WITH A 6 TO 12 HOUR PERIOD OF CATEGORICAL POPS SUNDAY
NIGHT INTO MONDAY MORNING. QPF WILL GENERALLY REMAIN BELOW 1/4 INCH
WITH THE EXCEPTION OF THE SOUTHEAST WHERE SOME HIGHER AMOUNTS MAY BE
NOTED. A MODERATING PACIFIC AIRMASS WILL FILTER INTO THE LOWER OHIO
VALLEY BEHIND THE FRONTAL BOUNDARY MONDAY AFTERNOON THROUGH TUESDAY
SO TEMPERATURES WILL REMAIN FAIRLY MILD FOR THE FIRST OF DECEMBER.
SO MONDAY... TEMPERATURES WILL HOLD IN THE 40S BUT WILL WARM INTO
THE LOWER 50S TUESDAY UNDER MOSTLY SUNNY SKIES. LOWS TUESDAY MORNING
WILL FALL INTO THE LOWER 30S.
WEDNESDAY THROUGH SATURDAY...
DURING THIS TIMEFRAME WE WILL TRANSITION INTO A MUCH MORE WINTER
WEATHER PATTERN WITH A DEEP UPPER LEVEL CLOSED LOW OVER THE GREAT
LAKES BY THE END OF THE WEEK. SO WHERE AS WE HAVE SEEN TEMPERATURES
ABOVE NORMAL FOR MOST OF NOVEMBER SOME MUCH COLDER AIR WILL ARRIVE
AND EARLY DECEMBER WILL FEEL MUCH MORE WINTER LIKE.
IN THE TRANSITION WE WILL HAVE A COUPLE OF SYSTEM AFFECT THE
FORECAST AREA. THE FIRST WILL BE A SOUTHERN STREAM UPPER LOW THAT
WILL TRACK FROM THE SOUTHWEST STATES ACROSS TEXAS AND THEN NORTHEAST
INTO THE LOWER OHIO VALLEY. THIS SYSTEM WILL BE RESPONSIBLE FOR A
NORTHWARD PUSH OF GULF MOISTURE WHICH WILL ARRIVE DURING THE DAY
WEDNESDAY WITH THE BULK OF THE MOISTURE AND PRECIPITATION MOVING
EAST OF THE AREA BEFORE AN ARCTIC AIRMASS DROPS INTO THE REGION
WEDNESDAY NIGHT. AS LONG AS THIS SOUTHERN STREAM SYSTEM ARRIVES
FIRST AND DOES NOT PHASE WITH THE NORTHERN STREAM... AS MENTIONED...
MOST OF THE PRECIPITATION WILL REMAIN IN THE FORM OF RAIN. WE DO
EXPECT A CHANGE TO SNOW BY THURSDAY MORNING AS THE FLOW SHIFTS TO
THE NORTHWEST AND MUCH COLDER AIR ARRIVES BUT ONLY RESIDUAL MOISTURE
WILL EXIST AND THEREFORE LITTLE OR NO SNOW ACCUMULATION IS
EXPECTED. THURSDAY WILL BE A BLUSTERY DAY WITH A BRISK NORTHWEST
WIND AND TEMPERATURES HOLDING IN THE UPPER 30S AND LOWER 40S.
FRIDAY AND SATURDAY WILL BE DRY AND COLD WITH HIGHS EACH DAY
STRUGGLING TO REACH 40 DEGREES AND LOWS FALLING INTO THE 20S.
&&
.AVIATION (06Z TAF ISSUANCE)...
VFR CONDITIONS WILL BE EXPECTED FOR MOST OF THIS TAF PERIOD. A COLD
FRONT WILL APPROACH THE AREA TONIGHT. AHEAD OF THE FRONT...THE SFC
PRESSURE GRADIENT WILL INCREASE TODAY CAUSING SW WINDS TO GUST UP TO
18 TO 22KTS THIS AFTERNOON AND EARLY EVENING. MID AND UPPER LEVEL
CLOUDS WILL BE ON THE INCREASE THIS AFTERNOON ALSO. FOR
TONIGHT...WE SHOULD SEE MOSTLY VCSH AHEAD OF THE FRONT THROUGH ABOUT
3Z-6Z. AROUND OR AFTER 6Z FLIGHT CONDITIONS WILL DROP INTO THE MVFR
CAT FOR CIGS/VSBYS AS MORE WIDESPREAD LIGHT TO MODERATE RAINFALL
ENTERS THE AREA AND PERSISTS THROUGH THE MORNING HOURS. THE FROPA
WIND SHIFT TO NW SHOULD OCCUR JUST BEYOND THIS TAF PERIOD IN THE
9Z-12Z TIME FRAME TOMORROW MORNING.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
SHORT TERM........LMS
LONG TERM.........JA
AVIATION..........AML
