FXUS63 KIND 300218
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
925 PM EST SUN NOV 29 2009
.UPDATED DISCUSSION...
THE COLD FRONT WILL MOVE OUT OF INDIANA BY 11 PM. MOST OF THE
UNSTABLE AIR IS ALONG AND AHEAD OF IT. ONLY RAIN THAT REMAINS IS
VERY LIGHT WHICH WILL MOVE OUT WITH THE FRONT. IT WAS ALSO
DECREASING IN COVERAGE. DUE TO THIS HAVE DROPPED THE RAIN WITH THE
UPDATED FORECAST. WINDS HAVE SHIFTED TO THE NORTHWEST SO ADJUSTED
FORECAST WINDS TO THAT. GOING TEMP FORECAST LOOKS OK.
&&
.AVIATION...DISCUSSION FOR 0Z TAFS.
A COLD FRONT HAS MOVED THROUGH KLAF AND WILL BE MOVING THROUGH THE
REST OF THE SITES OVER THE NEXT COUPLE OF HOURS. WINDS WILL SHIFT
FROM SOUTHWESTERLY TO NORTHWESTERLY AS THE FRONT MOVES THROUGH.
MAINLY LOWER MVFR CEILINGS ARE SEEN ASSOCIATED WITH THIS FRONT BUT
WITHIN THE PAST HOUR OR SO SOME IFR CEILINGS HAVE DEVELOPED JUST
BEHIND THE FRONT. WITH THIS DEVELOPMENT WILL TRY TO TIME IN A BRIEF
PERIOD OF IFR CEILINGS COINCIDENT WITH FRONTAL PASSAGE ALONG WITH
SOME MVFR VISIBILITIES THAT ARE ALSO OCCURRING BEHIND THE FRONT.
WILL RAISE THESE TO MVFR AFTER A COUPLE OF HOURS. THE NEXT CONCERN
WILL BE WHEN THE CLOUDS WILL RAISE TO VFR. WHILE THERE IS A BRIEF
BIT OF CLEARING CURRENTLY ACROSS EASTERN IOWA/NORTHWEST
ILLINOIS...THERE IS ANOTHER AREA OF MVFR CEILINGS BEHIND IT IN IOWA
AND MINNESOTA. THIS MATCHES WELL WITH LOW LEVEL MOISTURE IN TIME
HEIGHT CROSS SECTIONS AND THUS WILL KEEP MVFR CEILINGS AROUND UNTIL
AT LEAST MID MORNING.
&&
.PREV DISCUSSION...
SKIES HAVE BECOME MOSTLY CLOUDY ACROSS INDIANA AS A COLD FRONT
MOVES INTO THE AREA. THE FRONT IS CURRENTLY STRETCHING FROM LAKE
MICHIGAN...THROUGH ILLINOIS...AND INTO TEXAS. RAINFALL AND A FEW
EMBEDDED THUNDERSTORMS HAVE BEEN MOVING THROUGH NORTHEAST
ILLINOIS...SOUTHEAST WI...AND LOWER MICHIGAN ALL AFTERNOON. CLOSER
TO HOME...LIGHT RAIN AND DRIZZLE ARE FALLING ACROSS THE FORECAST
AREA AT THIS TIME.
THE FORECAST FOCUSES ON THE COLD FRONT/RAIN TODAY AND SNOW ON
WEDNESDAY AND THURSDAY.
THIS EVENING AND TONIGHT...RAIN WILL GRADUALLY MOVE ACROSS INDIANA
FROM NORTHWEST TO SOUTHEAST. THE BEST ISENTROPIC LIFT IS BETWEEN
MON 06 AND 09Z...AND THEN DRY AIR WILL QUICKLY FILTER IN BY
TOMORROW MORNING. THE DRY CONDITIONS WILL LAST THROUGH TUESDAY
NIGHT. TEMPERATURES WILL BE A BIT COOLER TOMORROW...BUT THEY WILL
WARM UP AGAIN BRIEFLY ON TUESDAY. MODELS WERE IN GOOD AGREEMENT
THROUGH TUESDAY NIGHT. SO...WENT WITH A BLEND...BUT LEANED TOWARD
THE HIGHER SIDE OF GUIDANCE. H850 TEMPS ARE AS HIGH AS 5 C THROUGH
THE BEGINNING OF THE WEEK.
IN THE EXTENDED...THE MAIN FOCUS CONTINUES TO BE THE MID WEEK
SYSTEM. MODELS HAVE COME INTO BETTER AGREEMENT...BUT THE GFS
CONTINUES TO BE THE OUTLIER...DRAGGING THE SYSTEM FURTHER SOUTH.
HOWEVER...LATEST MODEL RUNS OF THE GFS HAVE IT COMING INTO
AGREEMENT WITH THE CANADIAN AND ECMWF FOR A BRIEF TIME. THE GFS
THEN SPEEDS UP AND EXITS THE REGION FASTER THAN THE OTHER MODELS.
CONFIDENCE IN PRECIPITATION TYPE IS HIGHER WITH FORECAST SOUNDINGS
SHOWING TEMPERATURES BELOW FREEZING FROM WEDNESDAY NIGHT THROUGH THE
DURATION OF EVENT. RAIN COULD START MOVING INTO THE SOUTHERN
PORTIONS OF FORECAST AREA AS EARLY AS WED 12Z...BUT RAIN DOESN/T
REALLY GET GOING UNTIL WED 18Z. RAIN SHOULD START TRANSITIONING TO
A RAIN/SNOW MIXTURE BY THU 00Z...AND THEN ALL SNOW AFTER THU 06Z.
THE BULK OF THE PRECIPITATION SHOULD BE DONE LATE THURSDAY MORNING.
HOWEVER...THE ECMWF AND GFS WANT TO BRING MOISTURE INTO THE NORTHERN
FORECAST AREA FROM A SYSTEM OVER THE GREAT LAKES REGION. THE
CANADIAN IS THE OUTLIER IN THIS CASE...DECIDED TO LEAVE FLURRIES IN
THE FORECAST THROUGH FRIDAY MORNING. TOTAL SNOW ACCUMULATIONS...IF
ANY...WILL BE AROUND AN INCH.
AS FAR AS TEMPERATURES...STUCK CLOSE GUIDANCE...LOWS IN THE 20S AND
HIGHS IN THE MID TO UPPER 30S FOR DAYS 4 THROUGH 7.
FURTHER OUT...THE NEXT TROUGH SHOULD START MOVING IN SATURDAY
NIGHT...BUT MODELS ARE IN NO AGREEMENT AT THIS TIME.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...TDUD
AVIATION...CP
UPDATE...SH
