FXUS63 KLMK 270148
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
848 PM EST THU NOV 26 2009
...FORECAST UPDATE...
UPDATED THE FORECAST TO ACCOUNT FOR THE EXPECTED ENDING OF LIGHT
SPRINKLES OR MAYBE EVEN A FLURRY ACROSS THE BLUEGRASS BY EARLY
MORNING. THE MESO-NAM IS PRETTY ACCURATE WITH THE FORECAST
CLEARING LINE...WHICH HAS ALREADY RAPIDLY MOVED EASTWARDS INTO
WESTERN KENTUCKY. EXPECT CLEARING WELL BEFORE DAWN WEST OF
INTERSTATE 65...WITH CLOUDS LINGERING UNTIL SHORTLY AFTER DAWN
ACROSS THE BLUEGRASS AND SOUTHEASTERN INDIANA. WEST WINDS WILL
CONTINUE AROUND 10 MPH THROUGH FRIDAY.
.SHORT TERM (TONIGHT AND FRIDAY)...
A SHARP UPPER TROF WILL BRING OVERCAST SKIES AND SCATTERED LIGHT
PRECIPITATION TO THE REGION TONIGHT. FOR THE MOST PART IT APPEARS WE
WILL MERELY SEE SPRINKLES AND FLURRIES...WITH A FEW LOCATIONS MAYBE
RECEIVING ONE OR TWO HUNDREDTHS OF AN INCH OF LIGHT RAIN. THE BEST
CHANCE FOR ANY FLURRIES AND FOR ANY MEASURABLE LIGHT RAIN WILL BE
FROM SOUTHERN INDIANA INTO THE KENTUCKY BLUE GRASS.
AS THE TROF RACES OFF TO THE EAST THE LIGHT SCATTERED PRECIPITATION
WILL COME TO AN END AND WE WILL LIKELY SEE A FAIR AMOUNT OF CLEARING
BY SUNRISE FRIDAY...ESPECIALLY IN THE WEST. CLOUDS WILL CONTINUE TO
DECREASE OVER THE COURSE OF THE DAY FRIDAY AND IT SHOULD END UP
BEING A FAIRLY DECENT DAY. THE MAIN DETERRENT WOULD PROBABLY BE THE
WINDS...WHICH WILL BE FROM THE WEST AROUND 10 TO 15 MPH AND WILL PUT
A BIT OF A CHILL INTO THE AIR. MORNING WIND CHILLS ARE FORECAST IN
THE LOWER TO MIDDLE 20S.
LOWS TONIGHT SHOULD BE RIGHT AROUND THE FREEZING MARK. OTHER THAN A
FEW SLICK SPOTS ON ELEVATED ROADWAYS EARLY FRIDAY MORNING...THE
CHILLY TEMPERATURES AND SCATTERED FLURRIES SHOULD BE OF LITTLE
CONSEQUENCE TO TRAVELERS.
HIGH TEMPERATURES ON FRIDAY SHOULD REACH THE MIDDLE OR UPPER
40S...DEPENDING ON ANY REMAINING CLOUD COVER.
.LONG TERM (FRIDAY NIGHT - THURSDAY)...
FRIDAY NIGHT MONDAY NIGHT...
500MB HEIGHTS WILL BE ON THE RISE ACROSS THE REGION FRIDAY NIGHT AS
UPPER LEVEL AND SFC LOW MOVE OFF TO THE EAST AND HIGH PRESSURE
DRIFTS INTO THE REGION. MOSTLY CLEAR SKIES AND DRY WEATHER ARE
EXPECTED FOR FRIDAY NIGHT THROUGH SATURDAY NIGHT. OVERALL...BOTH
THE 26/12Z GFS/EURO AND THEIR ENSEMBLES ARE IN VERY GOOD AGREEMENT
HERE. LOWS FRIDAY NIGHT LOOK TO DROP INTO THE LOWER 30S IN THE
NORTH AND LOWER-MID 30S IN THE SOUTH. A WARMUP WILL BEGIN IN EARNEST
ON SATURDAY WITH HIGHS WARMING INTO THE LOWER-MID 50S IN THE
NORTHERN HALF WITH UPPER 50S ACROSS THE SOUTH. SOME HIGHS AROUND 60
MAY BE POSSIBLE IN LOCATIONS ALONG THE KY/TN BORDER. LOWS SATURDAY
NIGHT LOOK TO COOL BACK DOWN INTO THE LOWER 40S AS SOUTHWESTERLY PBL
FLOW WILL HELP KEEP TEMPS UP A BIT.
FOR SUN-MON NIGHT...LARGE SCALE MODELS CONTINUE TO BE IN GOOD
AGREEMENT WITH MAJOR HEIGHT FALLS SPREADING ACROSS THE PLAINS AS
VERY DECENT LOOKING TROF GETS CARVED OUT ACROSS THE PLAINS AND A CUT
OFF LOW FORMS OVER THE DESERT SOUTHWEST. THIS WILL LEAD US INTO A
DISTINCT SPLIT FLOW PATTERN. IN THE SPIRIT OF KEEPING A CONSISTENT
FCST GOING...HAVE CONTINUED TO FOLLOW A COMBINATION OF THE
DETERMINISTIC AND ENSEMBLE SOLUTIONS FROM THE EURO THROUGH THIS PD.
MORE PROGRESSIVE NORTHERN BRANCH WILL SEND ITS MID-LEVEL WAVE
THROUGH THE REGION LATE SUN THROUGH MON NIGHT. DEEP MOISTURE INFLUX
COURTESY OF THE SOUTHERN JET WILL SPREAD CLOUDS INTO THE REGION
DURING THE DAY ON SUNDAY WITH A THREAT OF SOME LIGHT PRECIPITATION
ACROSS THE FAR WESTERN PORTIONS OF THE FA. SFC LOW AND FRONTAL
BOUNDARY WILL MOVE ACROSS THE REGION LATE SUNDAY AND EARLY MONDAY
BRINGING WIDESPREAD SHOWERS TO THE REGION. HAVE GONE AHEAD AND
RAISED POPS SIGNIFICANTLY HERE GIVEN THE RECENT MODEL TRENDS AND
REASONABLE AGREEMENT WITHIN THE MODELS. PRECIPITATION SHOULD
GRADUALLY END MONDAY NIGHT AS THE SYSTEM QUICKLY PULLS EASTWARD.
MILD READINGS ARE EXPECTED FOR SUNDAY WITH HIGHS IN THE LOWER TO MID
50S. SOME UPPER 50S WILL BE POSSIBLE ACROSS THE SOUTH AND SOUTHEAST
SECTIONS WHERE MORE SUNSHINE WILL BE POSSIBLE. LOWS SUNDAY NIGHT
LOOK TO DROP INTO THE LOWER-MID 40S...WITH HIGHS ON MONDAY TOPPING
OUT IN THE MID-UPPER 40S. MUCH COOLER AIR WILL ARRIVE INTO THE
REGION LATE MONDAY NIGHT AFTER THE PRECIPITATION HAS MOVED EAST.
LOWS LOOK TO DROP INTO THE LOWER 30S.
TUESDAY THROUGH THURSDAY...
AS THE NORTHERN STREAM H5 TROF SLIDES EAST...WE'LL BE LEFT A CUT OFF
LOW ACROSS THE DEEP SOUTH PART OF TEXAS. THE EURO TAKES THIS
MID-LEVEL LOW AND TRIES TO PHASE IT WITH ANOTHER NORTHERN STREAM
TROF BY THURSDAY. THE 26/12Z EURO ALMOST GETS THE THING TO
PHASE...BUT IT LOOKS LIKE IT MIGHT MISS. THE 26/12Z GFS IS MUCH
DIFFERENT KEEPING A LARGE GYRE TO THE NORTH AND LETTING THE SOUTHERN
STREAM LOW GO SOUTH AROUND ITS SOUTHERN PERIPHERY. SO WITH
CONTINUITY IN MIND...WE HAVE KEPT THINGS VERY CLOSE TO THE 26/12Z
EURO SOLUTION HERE. WITH THAT SAID...THE PHASING ATTEMPT WILL ALLOW
THE SOUTHERN STREAM SYSTEM TO BE PULLED NORTHWARD AND BRING A SFC
LOW UP FROM THE MS DELTA REGION AND INTO THE VIRGINIAS. TYPICALLY
THIS IS A GREAT TRACK FOR A WINTER STORM...BUT COLD AIR IS WELL
NORTHWEST OF HERE. SO ANOTHER RAINMAKER WILL IMPACT THE REGION FOR
WED/THU. FOR NOW HAVE GONE WITH CHC POPS...BUT IF THE EURO
CONTINUES IN THE SAME DIRECTION ITS BEEN GOING...WE'LL PROBABLY NEED
TO BUMP UP POPS IN LATER FORECASTS.
HIGHS TUES SHOULD WARM INTO THE LOWER 40S IN THE NORTH WITH MID 40S
IN THE SOUTH. A BRIEF MODERATION IN TEMPS IS EXPECTED FOR WEDNESDAY
WITH HIGHS WARMING BACK UP INTO THE UPPER 40S...WITH COOLER WEATHER
ARRIVING ON THE BACKSIDE OF THE DEPARTING WEATHER SYSTEM ON THU.
WENT CLOSE TO THE EURO 2M TEMPS HERE WITH HIGHS IN THE LOWER 40S.
OVERNIGHT LOWS THROUGH THE PD LOOK TO BE IN THE MID-UPPER 30S...WITH
UPPER 20S POSSIBLE BY FRIDAY MORNING.
BEYOND THE PERIOD...THE EUROPEAN RUNS CONTINUE TO SHOW A DECENT COOL
DOWN AS WE HEAD INTO THE END OF NEXT WEEK. THIS HAS BEEN ADVERTISED
IN THE LONG RANGE MODELING FOR A TIME. HOWEVER THERE IS CONCERN IN
THE RUN THAT SUGGESTS THAT THE H5 RIDGE OVER THE WESTERN U.S. MAY IN
FACT GET SQUEEZED ENOUGH BY THE APPROACHING PACIFIC JET THAT IT MAY
CUT OFF AND FLOOD THE CONUS WITH SOMEWHAT MILDER AIR.
ON THE HAND...THE NEW PHASE DIAGRAMS OF THE MJO SHOW IT NOW IN PHASE
6. THE MJO HAS NOT BEEN WELL FORECAST AT ALL IN THE LAST COUPLE OF
WEEK...EVEN BY THE UKMET MODEL. TYPHOON NIDA IS LIKELY TO HAVE AN
IMPACT ON THIS...AND MAY EVENTUALLY LEAD THE MJO TO GO INTO PHASE
7/8. THIS HAS RAMIFICATIONS IN THAT MAY ALLOW A POLAR VORTEX TO
DEVELOP ACROSS EASTERN CANADA AS A STRONGER RIDGE BUILDS ACROSS THE
WEST. THIS SOLUTION COULD LEAD TO A DECENT COLD OUTBREAK ACROSS THE
U.S. AS WE GET INTO THE 3RD WEEK OF DEC. FORECAST HEADACHES FOR
SURE!
&&
.AVIATION (00Z TAF ISSUANCE)...
AS A TROUGH MOVES ACROSS WEST VIRGINIA THIS EVENING...LIGHT
RAIN...POSSIBLY MIXED WITH AN ICE PELLET OR SNOWFLAKE...WILL END
FROM WEST TO EAST THIS EVENING.
LIGHT SPRINKLES WILL END AT SDF SHORTLY AFTER 00Z THIS EVENING...AND
END AT BWG AND LEX AFTER 03Z. UNTIL THEN EXPECT LITTLE RESTRICTION
TO VISIBILITIES...BUT CLOUD CIGS IN THE MVFR RANGE RANGING FROM 15
TO 30 HUNDRED FEET. WINDS WILL REMAIN FROM THE WEST AROUND 10 MPH
OVERNIGHT.
CLEARING WILL ARRIVE AT SDF IN THE 09 TO 12Z TIME FRAME...AND A FEW
HOURS LATER AT LEX AND BWG. WEST WINDS WILL INCREASE SLIGHTLY FRIDAY
AFTERNOON TO AROUND 10 TO 15 MPH.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
UPDATE.........JSD
SHORT TERM.....JSD
LONG TERM......MJ
AVIATION.......JSD
