FXUS61 KILN 250549
AFDILN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
1249 AM EST FRI DEC 25 2009

.SYNOPSIS...
A STRONG SURFACE LOW WILL LIFT NORTH UP THE MISSISSIPPI VALLEY
TONIGHT...SENDING AN OCCLUDED FRONT ACROSS THE REGION ON CHRISTMAS
DAY. THE LOW WILL MEANDER IN THE VICINITY OF IOWA CHRISTMAS DAY
AND SATURDAY...BEFORE LIFTING EAST INTO THE GREAT LAKES ON SUNDAY.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SEVERAL CONCERNS THIS EVENING...BUT OVERALL FORECAST IS ON TRACK
WITH MINOR ADJUSTMENTS TO SPEED UP RAIN ARRIVAL A BIT IN THE
SOUTH/WEST...AND BUMP WINDS UP LATE. 

990MB CYCLONE NOW DEEPENING QUICKLY OVER SRN MO AS PHASING OF
ENERGY IS OCCURRING OVER THE CENTRAL CONUS. 25.00Z RUC HAS GOOD
HANDLE ON THIS...AND ANOMALOUS 70-80KT SELY LOW LEVEL JET OVER
AL/TN BRINGING COPIOUS MOISTURE NORTHWARD IN A HURRY THIS EVENING.
PRECIPITABLE WATER OFF THE KILN 25.00Z SOUNDING ALREADY 180
PERCENT OF NORMAL WITH LOWER MS VALLEY RAOBS ALL CONTAINING
175-200 PERCENT NORMAL. AS LOW PIVOTS NORTH INTO NRN MO AND SERN
IA BY SUNRISE...LOW LEVEL JET ON THE SERN QUAD OF THE CYCLONE WILL
SWING NORTHEAST AND FOCUS INTENSE MOISTURE TRANSPORT INTO THE OHIO
VALLEY. THIS SHOULD CONTINUE TO PROMOTE DEVELOPMENT OF RAIN BANDS
ON THE ERN SIDE /GRADIENT/ OF THE MOISTURE TRANSPORT REGION...AN
AREA ALSO RIPE WITH ISENTROPIC /290-300K/ ASCENT STRONG Q/G
FORCING. GIVEN THE LOW WILL BE 985MB...AND STRONG GRADIENT OVER
OHIO BY 12Z...WENT AHEAD AND BUMPED UP SUSTAINED WINDS OVERNIGHT
IN MOST LOCATIONS. STILL DON/T THINK A WIND ADVISORY IS
NEEDED...THANKS TO THE VERY STRONG INVERSION WHICH SHOULD KEEP
HIGH GUSTS ALOFT ESPECIALLY CONSIDERING WARM ADVECTION/LIFT IN THE
LOWEST 1-2KM. INITIAL RAIN BAND JUST INCHING INTO FAR SWRN CWA
NOW...SO ADJUSTED RAIN WORDING/GRIDS IN THESE AREAS...AND STILL
LOOK FOR STRONGEST PUSH OF RAIN OVERNIGHT FROM SSW TO NNE.
TEMPERATURES HANGING TOUGH IN THE MID 30S BUT STRONG WAA WILL WIN
OUT IN TIME AND SHOULD SEE A STEADY OR SLOWLY RISING SCENARIO
OVERNIGHT.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/...
12Z MODELS ARE IN GOOD AGREEMENT...PLACING THE SFC LOW IN NE MO
BY 12Z FRI. OCCLUDED FRONT WILL LIFT NORTHEAST ACROSS THE FA FRI.
GFS/ECMWF/CANADIAN ARE A LITTLE QUICKER WITH THE FROPA THAN THE
NAM/UKMET. LEANED TOWARDS THE GFS/EC TIMING. AS OCCLUDED FNT LIFTS
NE ACRS FA...IT SHOULD BRING AN END TO THE WIDESPREAD RAIN. THERE
WILL BE A CHANCE OF LINGERING R BEHIND THE FNT...WITH PLENTY OF
LOW LEVEL MOISTURE AND WEAK LOW LEVEL CONVERGENCE. MIGHT SEE SOME
SNOW TRY TO MIX IN ACROSS THE NW COUNTIES IN THE AFTERNOON...BUT
LITTLE IF ANY SNOW ACCUMULATION IS EXPECTED.

ALL MODELS ARE TRYING TO BRING A DRY SLOT IN FRI NGT...AS OCCLUDED
FNT CONTINUES TO LIFT N...SO DRIED OUT THE FA AFT MIDNIGHT. H5 AND
SFC LOW BEGIN TO KICK OUT THE MS VLY ON SAT. THIS WILL GIVE SOME
LIFT TO THE WRN AREAS...SO WILL NEED A SMALL POP. THE OVERALL
FLOW IS SW...SO THIS IS NOT FAVORABLE TO SHSN EVERYWHERE. AS THE
LOWS KICK E SAT NGT...CHC OF SHSN WILL INCREASE.

MAV/MET TEMP GUIDANCE WERE VERY SIMILAR...SO DIDNT STRAY VERY FAR.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
WITH THE GFS COMING IN LINE WITH THE ECMWF...SNOW SHOWERS WILL BE 
LIKELY SUNDAY DUE TO A POTENT SHORT WAVE THAT WILL DROP DOWN FROM 
THE WESTERN GREAT LAKES. MODEL QPF IS RATHER SKIMPY AS USUAL WITH 
THIS TYPE OF SYSTEM...BUT THERE IS THE POTENTIAL FOR LIGHT SNOW 
ACCUMULATIONS. A FEW SNOW SHOWERS MAY PERSIST ON MONDAY WITH A 
LITTLE HELP FROM LAKE MICHIGAN MOISTURE CARRIED BY A NORTHWEST 
FLOW.  

HIGH PRESSURE WILL PROVIDE DRY WEATHER AS IT TRAVELS ACROSS THE 
REGION TUESDAY AND WEDNESDAY. A COLD FRONT AND ASSOCIATED WAVE OF 
LOW PRESSURE WILL BRING A CHANCE OF SNOW NEXT THURSDAY.

TEMPERATURES WILL BE BELOW NORMAL THROUGH THE PERIOD WITH HIGHS IN 
THE 20 AND 30S AND LOWS IN THE TEENS AND 20S.

&&

.AVIATION /05Z FRIDAY THROUGH TUESDAY/...
CONDITIONS WILL START OUT IN THE VFR CATEGORY HOWEVER MVFR
CONDITIONS WILL DEVELOP DURING THE OVERNIGHT HOURS AND CONTINUE
THROUGHOUT THE REST OF THE TAF PERIOD. A STRONG LOW PRESSURE
SYSTEM OVER MISSOURI WILL MOVE TO THE NORTH. RAIN HAS ALREADY
ARRIVED AT MOST OF THE TAF SITES AND WILL CONTINUE TO MOVE IN
OVERNIGHT AS LOW LEVEL JET BECOMES MORE PRONOUNCED OVER THE AREA.
AS HEAVIER RAIN MOVES IN CIGS WILL BEGIN TO DROP AS WELL AS
VISBYS. WINDS AND WIND GUSTS WILL ALSO BEGIN TO PICK UP...HOWEVER
INVERSION WILL KEEP WINDS FROM GUSTING MORE THAN GENERALLY IN THE
20 KT TO 30 KT RANGE. DID CONTINUE WIND SHEAR MENTION IN THE TAFS
WITH WINDS AT TWO THOUSAND FEET BEING STRONGER AND MORE SOUTHERLY
THAN AT THE SURFACE. FRONT MOVES THROUGH DURING THE LATE AFTERNOON
AND EARLY EVENING ON FRIDAY AND AS IT MOVES THROUGH COLDER AIR
WILL BE USHERED INTO THE REGION. BY THE TIME PRECIP HAS AN
OPPORTUNITY TO CHANGE OVER TO SOME SNOW IT WILL DECREASE IN
INTENSITY AND COVERAGE AND THEREFORE HAVE HANDLED THIS WITH A VCSH
MENTION.

OUTLOOK...MVFR CIGS POSSIBLE SATURDAY INTO MONDAY. MVFR/IFR
VSBYS POSSIBLE SUNDAY INTO SUNDAY NIGHT.

&&

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

&&

$$
SYNOPSIS...SITES
NEAR TERM...BINAU
SHORT TERM...SITES
LONG TERM...CONIGLIO
AVIATION...NOVAK