000
FXUS61 KILN 280836
AFDILN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
336 AM EST TUE DEC 28 2010
.SYNOPSIS...
HIGH PRESSURE WILL MOVE THROUGH THE REGION TO THE EAST THROUGH
WEDNESDAY...WITH SOUTHERLY WINDS BEGINNING TO BRING IN WARMER
CONDITIONS. PRECIPITATION CHANCES WILL INCREASE THROUGH THE END OF
THE WEEK AS A FEW WEATHER SYSTEMS MOVE INTO THE AREA FROM THE WEST.
&&
.NEAR TERM /TUESDAY/...
SURFACE HIGH PRESSURE WILL CONTINUE TO BUILD IN FROM THE SOUTHEAST
ON TUESDAY...WITH WINDS BEGINNING TO SWITCH AROUND TO THE SOUTH AS
WARM ADVECTION BEGINS. MAIN FORECAST CONCERN FOR TODAY WILL BE HOW
THE CLOUD SITUATION EVOLVES. SHALLOW LOW LEVEL MOISTURE IS RESULTING
IN WIDESPREAD LOW CEILINGS...BUT WITH A FEW BREAKS HERE AND THERE.
HAVE GENERALLY TRENDED THE GRIDS TOWARD A MOSTLY CLOUDY SOLUTION
TO ACCOUNT FOR THIS...GOING MORE TOWARD PARTLY CLOUDY BY AFTERNOON
AND EVENING AS THE BETTER MOISTURE PULLS TO THE EAST.
EXPECTING A SLIGHT MODIFICATION UPWARD IN TEMPS FROM
YESTERDAY...AND DID NOT GO FAR FROM GUIDANCE WITH GOOD AGREEMENT
ON THIS.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH FRIDAY/...
WITH SOME EXPECTED CLEARING ON TUESDAY NIGHT...HAVE GONE A BIT
BELOW GUIDANCE FOR LOW TEMPS. WARM ADVECTION WILL HELP THE AIRMASS
MODIFY A BIT...BUT A BETTER RADIATIONAL COMPONENT TO THE
TEMPERATURE CURVE SHOULD BRING THINGS DOWN A BIT MORE THAN THE
GUIDANCE NUMBERS MIGHT BE INDICATING.
NON-DIURNAL TEMPERATURES WILL BE IN PLAY BY WEDNESDAY NIGHT...AS
WARM ADVECTION JUST OFF THE SURFACE REALLY BEGINS TO PICK UP. THIS
WILL BE IN ADVANCE OF A WEAK SHORTWAVE THAT WILL MOVE INTO THE
REGION AT AROUND THE SAME TIME. MOIST ISENTROPIC ASCENT IN THE
WARM ADVECTION WILL COMBINE WITH THIS TO PRODUCE AN AREA OF
SHOWERS THAT WILL OVERSPREAD THE REGION...WITH THE BEST COVERAGE
IN THE WEST WHERE HIGH CHANCE POPS WERE PUT INTO THE GRIDS.
PRECIP TYPE WILL BE AN ISSUE HERE...WITH SURFACE TEMPS SLOWLY
CLIMBING OVERNIGHT BUT STILL NOT QUITE GETTING ABOVE 0C EVERYWHERE
UNTIL MID MORNING ON THURSDAY. MEANWHILE...BOTH THE GFS AND NAM
INDICATE THAT 925MB TEMPS WILL CLIMB ABOVE FREEZING ON WEDNESDAY
EVENING ACROSS THE VAST MAJORITY OF THE FORECAST AREA. WILL
THEREFORE KEEP THE FREEZING RAIN CHANCE IN ALL LOCATIONS EXCEPT
SOUTHWEST OF CINCINNATI...BEFORE SWITCHING THINGS TO ALL RAIN BY
14Z THURSDAY MORNING.
FORCING WILL BE MORE SPARSE BETWEEN SYSTEMS ON FRIDAY...BUT
THOUGHT IT PRUDENT TO KEEP A 20 POP HERE. WITH WARMER
TEMPS...PRECIPITATION SHOULD JUST BE RAIN AT THIS POINT.
NO BIG CHANGES WERE MADE TO THE TEMPERATURE FORECAST...BUT OPTED
NOT TO GO WITH THE WARMER MET NUMBERS GIVEN THE PRECIPITATION AND
EXPECTED CLOUD COVER.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
MODELS HAVE COME INTO GOOD AGREEMENT WITH FRONTAL SYSTEM FOR THIS
WEEKEND. THE 12Z GFS AND BOTH THE 00Z/12Z ECMWF ARE PUSHING THE
FRONT THROUGH OUR AREA SATURDAY NIGHT. AHEAD OF THIS...EXPECT
WIDESPREAD PCPN TO OVERSPREAD THE AREA FROM THE WEST FRIDAY NIGHT
AND CONTINUE INTO SATURDAY. THE GFS IS HINTING AT A RIBBON OF VERY
WEAK ELEVATED INSTABILITY PUSHING ACROSS THE AREA LATE FRIDAY
NIGHT INTO SATURDAY MORNING. SUPPOSE THIS COULD LEAD TO AN
ISOLATED THUNDERSTORM...BUT WILL NOT MENTION IN FORECAST AS
DIURNAL TIMING IS UNFAVORABLE. THE MODELS ARE NOW MORE PROGRESSIVE
WITH THE FRONT WITH GOOD DRYING WORKING IN FROM THE WEST SATURDAY
NIGHT. WILL THEREFORE TAPER OFF PCPN FAIRLY QUICKLY BUT AS COOLER
AIR MOVES IN...SUPPOSE PCPN COULD BRIEFLY CHANGE OVER TO SNOW
BEFORE ENDING. HIGH PRESSURE WILL THEN BUILD INTO THE REGION
THROUGH EARLY NEXT WEEK...LEADING TO DRY CONDITIONS BUT COOLER
TEMPERATURES.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
SURFACE HIGH PRESSURE WILL REMAIN ANCHORED FROM THE OHIO VALLEY
SOUTHWARD INTO THE EASTERN GULF COAST STATES THROUGH THE TAF
PERIOD. DESPITE THIS RIDGE...LOW LEVEL MOISTURE TRAPPED BENEATH
RETURN WARM AIR ADVECTION FLOW WILL RESULT IN A PROLONGED PERIOD
OF MVFR/IFR CIGS AND MVFR VSBYS. THE RUC MODEL IS CURRENTLY THE
ONLY MODEL REALLY CAPTURING WHAT IS BEING SEEN ON SATELLITE AND
HAVE THUS USED FOR THIS FORECAST PACKAGE. HAVE BASICALLY KEPT
THINGS PESSIMISTIC UNTIL DAYTIME HEATING AND ADVECTION ERODE AND
PUSH LOW LEVEL MOISTURE EASTWARD...ALLOWING VFR CONDITIONS TO
RETURN BETWEEN 19Z AND 22Z. MOISTURE SPILLING IN FROM THE NW MAY
BRING SOME STRATOCUMULUS CLOUDS BETWEEN 4 AND 5 KFT BETWEEN 21Z
AND 00Z. ONCE THIS MOISTURE PUSHES THROUGH...JUST SOME MID AND
HIGH LEVEL CLOUDS ARE EXPECTED BETWEEN 04Z AND 06Z.
OUTLOOK...MVFR CIGS/VSBYS POSSIBLE WEDNESDAY NIGHT INTO THURSDAY
ALONG WITH A CHANCE OF RAIN/FREEZING RAIN. MVFR CIGS/VSBYS POSSIBLE
FRIDAY NIGHT INTO SATURDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...JGL
AVIATION...HICKMAN
