FXUS63 KLMK 261522
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
1022 AM EST SAT DEC 26 2009
...FORECAST UPDATE...
DRIER AIR HAS WORKED ITS WAY INTO THE FORECAST AREA THIS MORNING
WITH CLEAR SKIES PREVAILING ACROSS SOUTHERN INDIANA AND CENTRAL
KENTUCKY. CLOUDS OVER CENTRAL INDIANA WILL SLOWLY MAKE THEIR WAY
INTO SOUTHERN INDIANA BY MIDDAY AND SPREAD ACROSS THE FORECAST AREA
THIS AFTERNOON. HAVE MADE SOME ADJUSTMENTS TO REFLECT CURRENT SKY
CONDITIONS AND TEMPERATURES. OTHERWISE THE FORECAST LOOKS ON TRACK
FOR THIS AFTERNOON. UPDATE OUT SOON.
.SHORT TERM (TODAY AND TONIGHT)...
THE STORM SYSTEM THAT BROUGHT BLIZZARD CONDITIONS TO THE PLAINS
CHRISTMAS DAY HAS BECOME A SPRAWLING VERTICALLY STACKED SYSTEM
ROUGHLY CENTERED OVER ILLINOIS. SURFACE LOW PRESSURE IS CURRENTLY OVER
IOWA AND WILL CONTINUE TO WEAKEN AND SLOWLY MOVE TOWARDS MICHIGAN BY
EARLY SUNDAY. A COUPLE OF SUBTLE WEAKER DISTURBANCES ARE ROTATING
AROUND THE WEST SIDE OF THE MAIN 500MB CLOSED LOW AND WILL MOVE
SOUTH ACROSS KANSAS AND SOUTH DAKOTA LATER THIS MORNING.
DRY MID LEVEL AIR HAS OVERSPREAD THE LOWER OHIO VALLEY. OUR MAIN
FORECAST CHALLENGES THROUGH EARLY SUNDAY WILL BE CLOUDS AND
TEMPERATURES. CURRENT SATELLITE TRENDS ROUGHLY CONFIRM THE NAM-12
FORECAST IN BRINGING CLEARING SKIES NORTH OF INTERSTATE 64 DURING
THE PRE-DAWN HOURS. EVEN THE EDGE OF THE CLOUD SHIELD NOW STRETCHING
ACROSS SOUTHERN ILLINOIS SEEMS TO BE ERODING...OR AT LEAST NOT
FILLING IN TOWARDS THE EAST.
EXPECT MOSTLY CLEAR SKIES FOR A GOOD PORTION OF THIS MORNING. THE
NAM-12 FORECASTS A WEAK REINFORCING COLD FRONT THAT WILL MOVE ACROSS
CENTRAL KENTUCKY LATE THIS AFTERNOON. EXPECT THAT CLOUDS WILL
INCREASE BY MID TO LATE AFTERNOON AND BECOME MOSTLY CLOUDY THIS
EVENING AS STEEPENING LAPSE RATES WILL AID IN STRATO-CU DEVELOPMENT.
WITH COLDER AIR LAGGING ACROSS MISSOURI AND ILLINOIS
TODAY...TEMPERATURES WILL ACTUALLY SEEM REASONABLE THIS AFTERNOON.
WITH HIGHS LIKELY REACHING THE LOWER 40S...TODAY MAY PROVE THE
WARMEST DAY THROUGH AT LEAST THE MIDDLE PORTION OF NEXT WEEK.
SOUTH WINDS AROUND 10 MPH THIS MORNING WILL INCREASE THIS AFTERNOON
TO AROUND 15 TO 20 MPH FROM THE SOUTHWEST.
.LONG TERM (SUNDAY - FRIDAY)...
THE UPPER AIR PATTERN THROUGH THE MIDDLE OF THIS COMING WEEK WILL BE
MORE ZONAL THAN THE WEEK JUST ENDING...WITH GENTLY ROLLING RIDGES
AND TROFS MOVING ACROSS THE COUNTRY.
THE FIRST WEATHER-MAKER TO DEAL WITH WILL BE THE LAST VESTIGES OF
THE HUGE STORM THAT WALLOPED THE PLAINS OVER CHRISTMAS. ITS
DISSIPATING SURFACE LOW WILL CROSS THE UPPER GREAT LAKES SUNDAY AND
WILL DRAG A VERY WEAK COLD FRONT THROUGH THE LMK CWFA. UPPER
VORTICITY WILL BE SWINGING THROUGH THE TROF OVERHEAD AT ABOUT THE
SAME TIME. MOISTURE WILL BE MOST PLENTIFUL OVER SOUTHERN INDIANA AND
NORTHERN KENTUCKY. PRECIPITATION WILL BE IN THE FORM OF SNOW...WITH
HALF AN INCH TO AN INCH POSSIBLE NORTH AND A DUSTING SOUTH. HOWEVER
HIGH TEMPERATURES IN THE MIDDLE TO UPPER 30S WILL MELT MUCH OF WHICH
FALLS AND MAY MIX SOME RAIN INTO THE PRECIPITATION...ESPECIALLY IN
SOUTHERN KENTUCKY IN THE AFTERNOON. THE PRECIPITATION WILL TAPER OFF
FROM WEST TO EAST SUNDAY NIGHT.
DRY WEATHER CAN BE EXPECTED MONDAY THROUGH TUESDAY NIGHT AS A
NORTH-SOUTH ORIENTED RIDGE OF HIGH PRESSURE MOVES FROM THE PLAINS TO
THE EAST COAST. THE AIR ASSOCIATED WITH THIS RIDGE IS NOT TERRIBLY
COLD...ABOUT 5 TO 8 DEGREES COOLER THAN NORMAL FOR THIS TIME OF YEAR.
BY MID WEEK ONE AREA OF LOW PRESSURE WILL BE MOVING EAST ACROSS FAR
SOUTHERN CANADA WHILE ANOTHER DEVELOPS OVER THE GULF OF MEXICO AND
MOVES EAST ALONG THE COAST. A LENGTHY TROF WILL CONNECT THE TWO LOWS
AS THEY MOVE EASTWARD APPROXIMATELY IN TANDEM. THE GULF LOW WILL
BEAR THE CLOSEST WATCHING AS MODELS ARE SUGGESTING IT WILL TAKE A
TRACK VERY SIMILAR TO THE GULF LOW THAT BROUGHT A FOOT OF SNOW TO
EASTERN KENTUCKY ON DECEMBER 18-19. THIS WEEK/S LOW APPEARS TO BE
WEAKER THAN THAT ONE BUT IS STILL INTRIGUING. WILL HAVE TO KEEP A
CLOSE EYE ON IT. THE 1000-500 HPA 5400M THICKNESS LINE IS DRAPED
RIGHT ACROSS THE MIDDLE OF THE LMK CWFA WEDNESDAY AND POSSIBLY
WEDNESDAY NIGHT SO ONCE AGAIN THE TEMPERATURE PROFILE WILL BE
CRITICAL TO WHAT KIND OF PRECIP WE END UP GETTING. HAVE UPPED POPS
AS MUCH AS POSSIBLE FOR WEDNESDAY AND WEDNESDAY NIGHT WHILE NOT
STRAYING TOO FAR FROM MY NEIGHBORS' POPS FOR COORDINATION SAKE. WILL
NEED TO HAVE BOTH RAIN AND SNOW IN THE FORECAST.
&&
.AVIATION (12Z TAF ISSUANCE)...
MOSTLY CLEAR SKIES EXPECTED AT ALL TAF SITES THROUGH AROUND 15Z.
COOLER AIR WILL BEGIN TO ARRIVE LATER TODAY AND STRATO-CU WILL
LIKELY ARRIVE FROM THE NORTHWEST AS LAPSE RATES STEEPEN THIS
AFTERNOON. EVEN AS CLOUD COVER INCREASES THIS EVENING...CIGS WILL
STAY VFR THROUGH 06Z SUNDAY.
SOUTH SOUTHWEST WINDS ARE EXPECTED TO CONTINUE AROUND 10 TO 12KT
THROUGH AROUND 15Z THIS MORNING...THEN INCREASE TO JUST OVER 15KT
AFTER 15Z TODAY. WINDS MAY GUST ABOVE 25KT AT TIMES THIS AFTERNOON.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
UPDATE.........EES
SHORT TERM.....JSD
LONG TERM......13
AVIATION.......JSD
