FXUS63 KLMK 021950
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
250 PM EST WED DEC 2 2009
.SHORT TERM (TONIGHT AND THURSDAY)...
19Z SFC ANALYSIS REVEALS SFC LOW PRESSURE SYSTEM NOW IN SOUTH
CENTRAL TENNESSEE. 3HR PRESSURE FALLS WERE STRONGEST ACROSS
EAST-CENTRAL KY INCLUDING THE BLUEGRASS REGION SUGGESTING THE LOW
WILL CONTINUE NORTHEAST THROUGH THE AFTERNOON. THIS IS IN GOOD
AGREEMENT WITH THE SHORT TERM ENSEMBLE GUIDANCE. SKIES WERE CLOUDY
ACROSS THE ENTIRE STATE. A LITTLE BIT OF A DRY PUNCH WAS WORKING
NORTHWARD INTO THE TOMPKINSVILLE/BURKESVILLE/ALBANY AREA OF FAR
SOUTHERN KY. THIS PARTIAL CLEARING IS IS VERY SMALL AND WILL NOT
LAST LONG. CONVECTIVE ACTIVITY HAS BEEN NON-EXISTENT THIS
AFTERNOON. HOWEVER...SOME CONVECTION IS TRYING TO DEVELOP ACROSS THE
PLATEAU OF TN AND MAY WORK INTO OUR FAR SE COUNTIES THIS AFTERNOON.
TEMPERATURES HAVE RISEN MODESTLY UNDER A GOOD SOUTHWEST FLOW AHEAD
OF THE SYSTEM. TEMPS RANGED FROM 55 DOWN AT LONDON TO 45 UP AT
HUNTINGBURG INDIANA.
SHORT TERM DETERMINISTIC AND ENSEMBLE GUIDANCE CONTINUES TO BE IN
VERY GOOD AGREEMENT WITH THE WEATHER OVER THE NEXT 24 HOURS. SFC
LOW OVER TN WILL MOVE NORTHEAST TONIGHT PASSING THROUGH THE HEART OF
CENTRAL KY ON ITS WAY TO ONTARIO CANADA...WHERE IT SHOULD ARRIVE BY
12Z THU. SHOWERS ARE EXPECTED TO CONTINUE ACROSS THE REGION AS THIS
SYSTEM MOVES THROUGH. SOME BACK END MOISTURE WILL ALSO WORK
EASTWARD ACROSS THE REGION TONIGHT. QUITE A BIT OF PRECIPITATION
SHOULD BE IN PROGRESS AT 00Z TONIGHT SO WILL CONTINUE HIGH POPS AT
THE BEGINNING OF THE PD. AS THE SURFACE LOW DEPARTS...MOISTURE WILL
AS WELL SO WE WILL SEE PRECIPITATION GRADUALLY WIND DOWN FROM THE SE
TO THE NE. IN GENERAL...PRECIPITATION SHOULD GENERALLY BE LIGHT IN
NATURE. MORE NOTICEABLE WILL BE THE WINDS. AS THE SFC LOW
DEEPENS...THE PRESSURE GRADIENT IS EXPECTED TO INCREASE TONIGHT SO
WINDS WILL AS WELL. IT WILL BE A COLD BLUSTERY NIGHT WITH WINDS
SUSTAINED AT 15-20MPH WITH GUSTS UP 25 MPH POSSIBLE. MODEST COLD
AIR ADVECTION WILL TAKE OVER TONIGHT ON THE HEELS OF THE GUSTY
WESTERLY WINDS. AS PRECIPITATION BEGINS TO WIND DOWN...A CHANGE
OVER TO SNOW SHOWERS IS EXPECTED TOWARD DAWN...MAINLY OVER THE
NORTHWEST THIRD OF THE FCST AREA. WITH TEMPERATURES EXPECTED TO
REMAIN ABOVE FREEZING...NO ACCUMULATION IS EXPECTED.
FOR THURSDAY...SKIES WILL REMAIN MOSTLY CLOUDY THROUGH THE DAY AS
COLD AIR ADVECTION CONTINUES TO INCREASE OVER THE REGION. THE
COLDER AIR ALOFT MOVING IN WILL HELP CONTRIBUTE TO STEEPENING LAPSE
RATES ACROSS THE REGION. SOME LIGHT SNOW SHOWERS WILL BE POSSIBLE
ACROSS THE NORTHERN HALF DURING THE MORNING HOURS AND QUICKLY
DIMINISH TO SNOW FLURRIES DURING THE AFTERNOON. COMBINATION OF
CLOUDY SKIES AND COLD NW WINDS WILL KEEP AFTERNOON HIGHS WELL BELOW
NORMAL. AFTERNOON HIGHS WILL ONLY LIKELY WARM INTO THE UPPER 30S.
.LONG TERM (THURSDAY NIGHT - WEDNESDAY)...
THE EXTENDED PERIOD WILL BE CHARACTERIZED BY A SERIES OF UPPER LEVEL
TROUGHS MOVING THROUGH THE REGION BEGINNING WITH A LARGE TROUGH
MOVING OUT OF THE PLAINS AND ACROSS THE OHIO VALLEY THIS WEEKEND.
HOWEVER...BEFORE THAT SYSTEM COMES THROUGH WE WILL SEE DRIER
CONDITIONS BEGINNING THURSDAY NIGHT. WHILE PRECIPITATION IS NOT
EXPECTED THURSDAY NIGHT OR FRIDAY SKIES WILL REMAIN CLOUDY KEEPING
TEMPERATURES COOLER WITH OVERNIGHT LOWS THURSDAY NIGHT IN THE MID
AND UPPER 20S AND HIGHS ONLY CLIMBING INTO THE UPPER 30S TO LOW 40S
ON FRIDAY.
BY SATURDAY...THE TROUGH WILL SWING THROUGH THE AREA BRINGING
ANOTHER COLD FRONT AND REINFORCING SHOT OF COLDER AIR WITH IT.
HOWEVER...SKIES WILL CLEAR BEHIND THIS SYSTEM AS HIGH PRESSURE
BUILDS OVER THE AREA SO EXPECT THAT HIGH TEMPERATURES WILL NOT BE
COLD AS PREVIOUS EXPECTED WITH HIGHS MAINTAINING IN THE UPPER 30S TO
LOW 40S THROUGH SATURDAY. OVERNIGHT LOWS WILL FALL INTO THE MID 20S
SATURDAY NIGHT. BY SUNDAY...A SHORTWAVE RIDGE WILL MOVE ACROSS THE
OHIO VALLEY AND WITH SUNNY SKIES TEMPERATURES WILL REACH INTO THE
MID 40S AHEAD OF YET ANOTHER WEAK TROUGH FOR MONDAY.
A WEAK SHORTWAVE TROUGH WILL MOVE ACROSS IN AND OH ON MONDAY BUT
WILL NOT AFFECT TEMPERATURES MUCH AS THE AREA WILL REMAIN UNDER WEAK
WARM AIR ADVECTION WITH INCREASING MOISTURE ON SOUTHEASTERLY SURFACE
FLOW. HIGHS WILL REMAIN IN THE MID 40S WITH OVERNIGHT LOWS AROUND
30. AN UPPER LEVEL RIDGE OFF THE EAST COAST WILL BUILD BY MIDWEEK AS
YET ANOTHER TROUGH DIPS INTO THE CENTRAL PLAINS AND TEMPERATURES
WILL WARM IN RESPONSE TO THE UPPER 40S AND LOW 50S ON TUESDAY. BY
TUESDAY NIGHT...THE COLD FRONT ASSOCIATED WITH THE PLAINS TROUGH
WILL BE RACING TOWARD THE AREA AND WITH INCREASED SOUTHERLY SURFACE
FLOW MOISTURE WILL OVERRIDE INTO THE AREA AND RAINFALL LOOKS LIKE A
GOOD BET AT THIS TIME FOR TUESDAY NIGHT INTO WEDNESDAY. ANOTHER
BRIEF SHOT OF COLDER AIR WILL BE POSSIBLE FOR WEDNESDAY NIGHT AND
THURSDAY BEHIND THE COLD FRONT.
&&
.AVIATION (18Z TAF ISSUANCE)...
SFC LOW PRESSURE MOVING INTO SOUTH-CENTRAL TN WILL MOVE INTO CENTRAL
KENTUCKY LATER THIS EVENING AND INTO CENTRAL OHIO LATER TONIGHT. AS
THIS SYSTEM APPROACHES AND PASSES...WIDESPREAD CLOUDS AND
PRECIPITATION ARE EXPECTED. REGIONAL RADARS SHOW BULK OF
PRECIPITATION NOW MOVING NORTH OF THE TERMINAL SITES INTO CENTRAL
IN/OH. SOME ADDITIONAL SCATTERED SHOWERS ARE MOVING NORTHEAST
ACROSS WEST TN AND WILL BE IN THE AREA THIS AFTERNOON.
THERE IS STILL CONCERN THAT WHILE PRECIPITATION MIGHT BECOME MORE
SCATTERED...IT ALSO MAY TAKE ON A MORE CONVECTIVE CHARACTER RATHER
THAN THE STRATIFORM THAT WE'VE SEEN. CURRENT INDICATIONS SUGGEST
THAT ANY THREAT OF CONVECTIVE TYPE PRECIP WOULD BE LIMITED TO MAINLY
KBWG AND KLEX...BUT OVERALL THREAT SEEMS TO LOW GIVEN THE LACK OF
SFC BASED INSTABILITY.
SFC WINDS WILL BE DIFFICULT TO PREDICT THIS AFTERNOON AS THE SFC LOW
PASSES RIGHT THROUGH THE TERMINALS. SOUTHEAST TO EAST WINDS THIS
AFTERNOON WILL LIKELY GO MORE VARIABLE AS THE LOW MOVES THROUGH AND
THEN BECOME MORE WESTERLY TONIGHT. SPEEDS SHOULD ALSO INCREASE AS
WELL AS PRESSURE GRADIENT TIGHTENS AS SFC LOW DEEPENS. CIGS/VSBYS
ARE EXPECTED TO GENERALLY REMAIN IFR THIS AFTERNOON WITH SOME
IMPROVEMENT EXPECTED LATER TONIGHT WITH CIGS/VSBYS GOING TO MVFR AS
DEEPER MOISTURE PULLS OUT OF THE REGION.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
SHORT TERM........MJ
LONG TERM.........LMS
AVIATION..........MJ
