FXUS61 KILN 010555
AFDILN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
1255 AM EST TUE DEC 1 2009

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OVER THE OHIO VALLEY REGION THROUGH 
TUESDAY. ON WEDNESDAY...AN AREA OF LOW PRESSURE WILL MOVE INTO
THE OHIO VALLEY FROM THE SOUTH.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
A SFC RIDGE OF HIGH PRESSURE WILL REMAIN ACROSS THE OHIO VALLEY
OVERNIGHT. LATEST SATELLITE IMAGERY WAS SHOWING STRATOCUMULUS
CLOUDS SCT TO LOCALLY BKN...GENERALLY ALONG AND E OF I-75. AM
EXPECTING MOST OF THESE CLOUDS TO EXIT OUT OF THE AREA BY 06Z.
SOME SCATTERED MID LVL CLOUDS MAY SKIRT THE NRN ZONES. THUS...
SKIES WILL BE CLEAR TO MOSTLY CLEAR. SOUTH TO SOUTHWEST WINDS
SHOULD PICK UP A TAD OVERNIGHT...ESPECIALLY NORTH...AS A SFC TROF
MOVES ACRS THE GREAT LAKES. THE WIND AND MAINLY CLEAR SKIES WILL
MAKE FOR A TRICKY LOW TEMPERATURE FORECAST. HAVE BASICALLY WENT A
LITTLE COOLER THAN PREVIOUS FORECAST WITH LOWS GENERALLY DROPPING
INTO THE 25 TO 30 DEGREE RANGE.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
NOT MUCH TO SPEAK OF ON TUESDAY...WITH HIGH PRESSURE TO THE SOUTH
AND SOME MODEST SOUTHWESTERLY FLOW. CLOSE TO GUIDANCE FOR HIGHS.

AN AREA OF LOW PRESSURE DEVELOPING NEAR THE GULF COAST WILL BE THE
MAIN CONCERN FOR THIS PERIOD OF THE FORECAST. A SHARP 500MB TROUGH
WILL PULL A LOW UP THE MISSISSIPPI RIVER AND THEN INTO THE OHIO
VALLEY BY WEDNESDAY NIGHT. MODEL TIMING HAS COME INTO PRETTY GOOD
AGREEMENT...WITH DIFFERENCES MAINLY IN PLACEMENT. THE NAM IS
FURTHEST WEST...BRINGING THE LOW UP THROUGH INDIANA...WHILE THE
GFS AND ECMWF TAKE IT FURTHER EAST INTO PENNSYLVANIA. THE GEM IS A
GOOD COMPROMISE OF THE TWO AND GENERALLY STUCK CLOSE TO IT.

HAVE INCLUDED SOME PRETTY HIGH POPS...WITH THE BEST CHANCE FOR
GOOD RAINFALL COMING IN THE STRONG ISENTROPIC LIFT AHEAD OF THE
LOW. LINGERING MOISTURE WILL LEAD FOR A CHANCE OF MORE SPOTTY
SHOWERS CONTINUING THROUGH WEDNESDAY NIGHT INTO THURSDAY MORNING.

TEMPS ON WEDNESDAY NIGHT WERE A BIT TRICKY WITH A NON-DIURNAL
CURVE IN THE FORECAST. GOOD AGREEMENT ON A SURGE OF HIGHER THETA-E
AIR RIDING AT LEAST INTO THE SOUTHWEST CORNER OF THE FORECAST
AREA...AND SURFACE TEMPERATURES IN THIS AREA MAY PEAK OUT AFTER
SUNSET. AFTERWARDS...THE COLD FRONT WILL PUSH THROUGH BY SUNRISE
THURSDAY...LEADING TO SHARPLY FALLING TEMPERATURES WITH COLD
ADVECTION.

BECAUSE OF THE COLD ADVECTION...PROFILES LOOK COLD ENOUGH FOR A
TRANSITION TO SNOW IN THE WESTERN PORTION OF THE FORECAST AREA.
WITH ONLY SPOTTY PRECIPITATION AROUND AT THAT TIME...DO NOT EXPECT
APPRECIABLE ACCUMULATIONS.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
LATEST MODELS A BIT WARMER WITH SYSTEM TO MOVE THROUGH MIDWEEK. GFS 
AND ECMWF SIMILAR WITH LOCATION OF SURFACE LOW ACROSS NY STATE BY 
12Z THU MORNING. GFS CONTINUES TO BE MORE PROGRESSIVE WITH MOVEMENT 
OF UPPER LEVEL TROF THU AND FRI THAN ECMWF. FORECAST WILL TREND 
TOWARD SLOWER ECMWF. DEEP UPPER LEVEL TROF WILL SETTLE INTO THE 
GREAT LAKES ON THU. FORECAST AREA WILL SEE CHANCE OF SNOW SHOWERS IN 
THE MORNING WITH A CHANCE OF SEEING SOME RAIN SHOWERS FOR A BRIEF 
PERIOD IN THE AFTERNOON BEFORE CHANGING BACK TO A CHANCE OF SNOW 
SHOWERS. ANY SCATTERED SNOW SHOWERS WILL END LATE FRI AFTERNOON. AS 
SURFACE RIDGING WILL BUILD INTO THE OHIO VALLEY. 

MODEL SOLUTIONS SHOW A LARGE DIVERGENCE THIS WEEKEND WITH ECMWF 
MAINTAINING THE UPPER LOW OVER THE GREAT LAKES WHILE THE GFS IS MORE 
PROGRESSIVE. WILL FOLLOW SOLUTION CLOSER TO ECMWF WITH CONTINUED  
COLD TEMPERATURES. TEMPERATURES IN THE EXTENDED PERIOD MAY BE SOME 
OF THE COLDEST SO FAR THIS YEAR.  AT THIS TIME...WILL KEEP DRY 
CONDITIONS AFTER FRIDAY. HOWEVER...FORECAST AREA MAY SEE A FEW 
SHOWERS SAT OR SUN IF THE SLOWER ECMWF TRACK OF THE UPPER LOW 
VERIFIES.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
VFR CLOUDS ASSOCIATED WITH WEAK H5 S/W DROPPING THRU THE LAKES ARE
DROPPING SE THRU NRN OH AND MAY BRUSH CMH/LCK. ONLY WENT A TEMPO
FOR SCT080 FOR A FEW HOURS AT THE BEGINNING OF THE TAF PERIOD. 

CENTER OF SFC HIGH WILL SLIDE OFF TO THE CAROLINAS TODAY...BUT
HIGH SHOULD REMAIN IN CONTROL OF THE TAFS. LOW LEVELS WILL REMAIN
DRY TODAY. H3 AND H5 WILL SEE AN INCREASE IN MOISTURE AFT
00Z...WITH BKN CI EXPECTED AFT 06Z.

OUTLOOK...MVFR/IFR CIGS/VSBYS POSSIBLE WEDNESDAY NIGHT INTO
THURSDAY. MVFR CIGS POSSIBLE ON FRIDAY.

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.

&&

$$
SYNOPSIS...HATZOS/HICKMAN
NEAR TERM...HICKMAN
SHORT TERM...HATZOS
LONG TERM...PARKER
AVIATION...SITES