FXUS63 KLMK 260552
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
1252 AM EST THU NOV 26 2009
...UPDATED AVIATION DISCUSSION...
.SHORT TERM (TONIGHT AND THURSDAY)...
A SHARP UPPER TROF WILL BE DIGGING INTO THE EASTERN UNITED STATES AS
LOW PRESSURE ROTATES OVER THE UPPER GREAT LAKES BEFORE SPINNING DOWN
THURSDAY NIGHT. A VERY WEAK TROF WILL CROSS THE LMK CWFA FROM WEST
TO EAST TONIGHT. THERE IS VERY LITTLE CONVERGENCE OR MOISTURE
ASSOCIATED WITH THIS FEATURE. SOME ISOLATED PATCHES OF LIGHT RAIN
COULD MANAGE TO SQUEEZE OUT OF THE CLOUDS ROUGHLY ALONG AND NORTH OF
INTERSTATE 64 WITH A FEW SPRINKLES TO THE SOUTH...MOSTLY IN THE
MIDDLE OF THE NIGHT...AND THAT SHOULD BE ABOUT IT. BY MORNING WHEN
WE REACH OUR EXPECTED LOWS IN THE MIDDLE TO UPPER 30S THE TROF WILL
BE OFF TO OUR EAST TAKING ITS PRECIPITATION CHANCES WITH IT.
ON THANKSGIVING THE MORNING MIGHT NOT BE TOO BAD...WITH DRY
WEATHER AND POSSIBLY SOME PARTIAL SUNSHINE. HOWEVER CONDITIONS WILL
DETERIORATE IN THE AFTERNOON AS ANOTHER VERY WEAK SURFACE TROF
APPROACHES FROM THE WEST. CLOUDINESS WILL INCREASE AND SCATTERED
LIGHT RAIN SHOWERS WILL BE POSSIBLE. THIS COMBINED WITH BRISK WEST
WINDS OF 10 TO 15 MPH AND HIGHER GUSTS AND TEMPERATURES ONLY IN THE
LOWER TO MIDDLE 40S WILL MAKE FOR A SOMEWHAT RAW AFTERNOON.
THIS TROF WILL HAVE MORE MOISTURE WITH IT THAN THE PREVIOUS ONE...SO
CHANCES OF PRECIPITATION WILL BE A BIT BETTER THURSDAY AFTERNOON AND
EVENING. BY THE LATE AFTERNOON OR EARLY EVENING HOURS THE MOISTURE
BECOMES DEEP ENOUGH THAT IT WILL REACH UP INTO COLDER LEVELS OF THE
ATMOSPHERE AND WE COULD SEE A FEW WET SNOWFLAKES OR SOME SOFT SLEET
MIX IN WITH THE LIGHT RAIN.
AS THE TROF CONTINUES TO PUSH TO THE EAST THURSDAY NIGHT
PRECIPITATION WILL GRADUALLY END. THE BEST CHANCE FOR ANY RAIN/SNOW
MIX WILL BE IN THE BLUE GRASS. LOWS EARLY FRIDAY MORNING LOOK TO BE
IN THE 30 TO 35 DEGREE RANGE.
.LONG TERM (THURSDAY NIGHT - WEDNESDAY)...
FRIDAY THROUGH SUNDAY...
SHORT-MED RANGE MODELS CONTINUE TO BE IN VERY GOOD AGREEMENT AT THE
BEGINNING OF THE PERIOD WITH A HIGHLY AMPLIFIED UPPER LEVEL FLOW.
LARGE SCALE TROF AND CLOSED H5 LOW IS FCST TO CONTINUE TO LIFT NE
THROUGH NEW ENGLAND WITH SFC CYCLONE GOING UP THE NEUS COAST.
STRONG NORTHWEST FLOW WILL BE THE RULE IN THE OHIO VALLEY ON FRIDAY
WITH SOME SCT LIGHT SNOW SHOWERS POSSIBLE FOR A TIME FRIDAY
MORNING...MAINLY ACROSS THE BLUEGRASS REGION. THIS ACTIVITY SHOULD
END BY MID-MORNING AS DRIER AIR ADVECTS IN FROM THE WEST AND
MOISTURE MOVES OFF TO THE EAST. AFTER THAT...SFC HIGH PRESSURE AND
LARGE SCALE H5 RIDGING WILL BUILD INTO THE REGION AS A DEEP TROF IS
CARVED OUT OVER THE DESERT SOUTHWEST. HEIGHTS WILL START TO FALL
LATE SATURDAY AND INTO SUNDAY AS THE UPPER TROUGH HEADS EASTWARD. A
BROAD SOUTHWESTERLY FLOW WILL ALLOW A QUICK MODERATION IN
TEMPERATURES AS WELL...AFTER A BELOW NORMAL EARLY HOLIDAY PERIOD.
THE WEATHER LOOKS DRY FOR SATURDAY AND SUNDAY...THOUGH THE
APPROACHING TROF TO THE WEST WILL BEGIN TO SPREAD CLOUDS INTO THE
REGION DURING THE DAY ON SUNDAY.
AS MENTIONED ABOVE...TEMPERATURES WILL START OFF BELOW NORMAL ON
FRIDAY WITH A GRADIENT OF TEMPERATURE LIKELY SETTING UP. HIGHS WILL
RANGE FROM THE UPPER 30S OVER THE NORTHEASTERN/NORTHERN BLUEGRASS
SECTIONS TO THE LOWER-MID 40S ACROSS THE I-65 CORRIDOR AND POINTS
WEST. LOWS FRIDAY NIGHT WILL BE LARGELY DEPENDENT ON SKY
COVER...WHICH SHOULD BE MOSTLY CLEAR AND LOW SHOULD DROP INTO THE
UPPER 20S TO THE LOWER 30S. AS SOUTHWESTERLY FLOW GETS QUICKLY
RE-ESTABLISHED ON SATURDAY...MILDER WEATHER LOOKS ON TAP. HIGHS
SATURDAY SHOULD RANGE FROM THE MID-UPPER 40S IN THE NORTHEAST TO THE
LOWER-MID 50S ACROSS THE CENTRAL AND SOUTHWEST SECTIONS. SAT NIGHT
TEMPS WILL BE MILDER DUE TO THE SOUTHERLY FLOW AND A BIT OF MID-HIGH
LEVEL CLOUDS STREAMING OUT OF THE SOUTHWEST U.S. LOWS SHOULD DROP
INTO THE UPPER 30S TO THE LOWER 40S. CONTINUED MILD WEATHER LOOKS
ON TAP FOR SUNDAY WITH AFTERNOON HIGHS TOPPING OUT IN THE LOWER 50S.
SUNDAY NIGHT THROUGH WEDNESDAY...
BY LATE SUNDAY...CONSENSUS OF THE 12Z DETERMINISTIC AND ENSEMBLE
GUIDANCE FROM THE GFS/EURO/UKMET/CMC ARE IN GENERAL AGREEMENT WITH A
DEEP TROF DEVELOPING ACROSS THE DESERT SOUTHWEST. THIS TROF LOOKS
TO GO POSITIVE TILT WHICH WILL IN EFFECT LEAD TO A SPLIT FLOW
PATTERN ACROSS THE CONUS NEXT WEEK. IN THE 25/12Z MODELS...THE GFS
IS MORE PROGRESSIVE WITH THE NORTHERN STREAM WHICH IT KEEPS THE FLOW
SPLIT. ON THE OTHER HAND...THE 25/12Z EURO SOLUTION IS KEEPS THINGS
LESS SPLIT AND ALLOWS A SLOWER PROGRESSION OF A WEATHER SYSTEM THAT
DEVELOPS ON THE LEE SIDE OF THE ROCKIES. IN GENERAL...THE 25/12Z
EURO SOLUTION IS SLIGHTLY SLOWER THAN ITS 25/00Z COUNTERPART AND
GENERALLY AGREES WITH ITS ENSEMBLES. SO RATHER THAN MAKING DRASTIC
CHANGES TO THE FORECAST...WE WILL BE SIMPLY TRENDING THE FCST CLOSER
TO THE 25/12Z EURO SOLUTION AT THIS TIME.
WITH THAT SAID...THE SLOWER PROGRESSION AND LESSER SEPARATION
BETWEEN THE STREAMS IN THE EURO LOOK TO ALLOW SFC CYCLOGENESIS TO
OCCUR OVER TX WITH A LOW TRACKING FROM TX NE THROUGH AR/MO/IL.
AGAIN THIS IS A SIMILAR STORM TRACK THAT WE'VE SEEN THIS FALL. WITH
THIS TRACK...A DECENT PRECIPITATION EVENT LOOKS TO AFFECT THE REGION
FOR LATE SUNDAY NIGHT THROUGH TUESDAY NIGHT. WIDESPREAD SHOWERS AND
PERHAPS A FEW RUMBLES OF THUNDER WILL BE IN THE REGION ESPECIALLY
MON-TUESDAY. AS FOR QPF...AMOUNTS OF ONE QUARTER TO ONE HALF INCH
SEEM LIKELY WITH THIS SYSTEM. THE SYSTEM LOOKS TO PULL THE NE
QUICKLY TUE NIGHT WITH DRIER AND COOLER WEATHER SETTING IN FOR
WEDNESDAY.
LOWS SUNDAY NIGHT LOOK TO DROP INTO THE LOWER TO MID 40S WITH HIGHS
ON MONDAY TOPPING OUT IN THE UPPER 40S TO THE LOWER 50S. LOWS TUES
MORNING WILL DROP INTO THE MID-UPPER 30S WITH HIGHS TUE AFTERNOON
REACHING THE LOWER 40S IN THE NE TO THE UPPER 40S-LOWER 50S IN THE
SOUTHWEST. MUCH COOLER WEATHER SHOULD POUR INTO THE REGION TUE NIGHT
WITH LOWS DROPPING INTO THE LOWER 30S AND HIGHS ON WED LOOK TO TOP
OUT IN THE LOWER 40S. WE WENT WELL BELOW MOS HERE AND STUCK CLOSER
TO THE 2M TEMPS WHICH HAVE BEEN VERIFYING QUITE WELL RECENTLY.
LOOKING AHEAD TOWARD THE REMINDER OF THE WORKWEEK...THE LONG RANGE
MODELS CONTINUE TO ADVERTISE A HIGHLY AMPLIFIED FLOW ACROSS NORTH
AMERICA. AN ACTIVE SOUTHERN STREAM WITH ANOTHER WAVE LOOKS TO SPIN
UP CYCLOGENESIS ACROSS THE SE TX COAST WITH A LOW MOVING UP THE
EAST SIDE OF THE APPALACHIANS. THE GFS LIFTS THE UPPER LOW FAST
RESULTING IN A FURTHER WESTWARD TRACK...WHICH WOULD BRING ANOTHER
ROUND OF RAIN TO THE REGION AS LOW-LEVEL COLD AIR STAYS TO THE NORTH
AND WEST. AFTER THAT...THE EURO HAS BEEN SUGGESTING CARVING OUT A
LARGE TROUGH ACROSS THE CENTER OF THE COUNTRY WHICH SHOULD BRING A
FAIR AMOUNT OF COLD AIR DOWN INTO THE PLAINS. THIS AGREES VERY WELL
WITH THE EURO WEEKLIES THAT SHOW -2.5 -2.5 DEG C 850 TEMP ANOMALIES
ACROSS THE GREAT PLAINS. EVENTUALLY THIS WILL SHIFT EASTWARD BUT
MODIFY A BIT. THE MODIFICATION OF THIS AIR WILL BE DETERMINED BY
WHAT THE MJO DECIDES TO DO. AT THIS TIME...IT IS FCST TO GO INTO A
NON-DETERMINANT PHASE WHICH WOULD TEND TO ALLOW TRANSIENT COLD AIR
SHOTS TO COME THROUGH WITH WARMUPS AS THEY DEPART.
&&
.AVIATION (06Z TAF ISSUANCE)...
A SHRTWV TROF AND ASSOCIATED SFC TROF WILL MOVE ACRS THE REGION
DURING MIDDAY THU. AN INCREASE IN LOW CLOUDS (HIGH MVFR TO VFR ) IS
EXPECTED BEHIND THE TROF WITH SOME AREAS OF LIGHT RAIN...AND
POSSIBLY SOME SNOW FLAKES DURING THE AFTN AND EARLY EVE. ANY SNOW
FLAKES WOULD BE MOST LIKELY AT SDF AND LEX. POST TROF WLY WINDS WILL
INCREASE THU WITH GUSTS AROUND 20KTS.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
SHORT TERM........JSD
LONG TERM.........MJ
AVIATION..........DK/11
