FXUS63 KIND 080233
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
930 PM EST MON DEC 7 2009
.UPDATE FOR THE REST OF TONIGHT...
NO CHANGES MADE TO CURRENT FORECASTS. CLOUDS SHOULD CONTINUE
OVERNIGHT MOST AREAS...ALTHOUGH A FEW HOLES IN THE CLOUD COVER HAVE
OPENED UP...ONE OVER NORTHEAST INDIANA AND ANOTHER IN THE FAR
SOUTHWEST. RAISED TEMPERATURES OVERNIGHT TEMPERATURES A DEGREE OR
TWO IN GRIDS ACROSS OUR SOUTH AND NORTHWEST SECTIONS. BUT THIS WAS
NOT ENOUGH TO JUSTIFY AN UPDATE.
&&
.AVIATION...DISCUSSION FOR THE 00Z TAFS.
WIDESPREAD MVFR CONDITIONS AND MODELS FAVOR KEEPING MVFR CLOUDS IN
TGNT UNTIL TOMORROW LATE MORNING WHEN SOME MIXING MAY OCCUR AHEAD OF
STRENGTHENING LOW PRESSURE SYTEM THAT WILL MOVE INTO THE MIDDLE
MISSISSIPPI VALLEY REGION LATE TUESDAY NIGHT. MODELS SUGGEST RAIN
ASSOCIATED WITH THIS SYSTEM WILL MOVE ACROSS THE TAF SITES AFTER 16Z
TOMORROW. MODELS ALSO SUGGEST CEILINGS WILL DROP TO MVFR OR EVEN IFR
WITH THE ONSET. WINDS WILL INCREASE TO 10 TO 15 KNOTS FROM THE EAST
TOMORROW AFTERNOON. BUFKIT SUGGESTS GUSTS TO 20 KNOTS.
&&
.SHORT TERM...
SURFACE ANALYSIS SHOWS LOW PRESSURE FORMING OVER THE DESERT
SOUTHWEST AND WEAK HIGH PRESSURE OVER THE SOUTHEAST. VISIBLE
SATELLITE SHOWS CLOUDY SKIES ACROSS THE FORECAST AREA. TEMPERATURES
WERE IN THE MIDDLE 30S WITH DEWPOINTS IN THE UPPER 20S TO LOW 30S
AND WINDS WERE OUT OF THE SOUTHWEST AT 5 TO 10 KTS.
FORECAST FOCUS IS ON WINDS/POPS/PRECIPITATION TYPE WITH TUESDAY
THROUGH WEDNESDAY NIGHT SYSTEM. AGAIN NAM SEEMS TO BE AN OUTLIER
WITH TIMING COMPARED TO THE GFS/ECMWF/GEM AND SO WILL DISCARD THE
NAM SOLUTION AND RELY ON A BLEND OF THE OTHERS.
DRY WEATHER TONIGHT AS WEAK HIGH PRESSURE IS ACROSS THE AREA BETWEEN
WEATHER SYSTEMS. TUESDAY A SURFACE LOW PRESSURE SYSTEM FORMS IN THE
INTERMOUNTAIN WEST AND SCOOTS TO THE CENTRAL PLAINS. THIS WILL CREAT
SOUTHERLY WINDS AHEAD OF THE SYSTEM WITH A FETCH OPENING UP FROM THE
GULF. ISENTROPIC LIFT ACROSS THE AREA STARTS UP IN THE MORNING AND
CONDENSATION PRESSURE DEFICITS INDICATE PRECIPITATION STARTING IN
THE AFTERNOON ACROSS THE AREA. PROBABILITIES ARE HIGHEST EARLIEST IN
THE SOUTH CLOSEST TO THE LIFT BUT EXPECT THEM TO OVERSPREAD THE
FORECAST AREA BY 0Z. COULD SEE THINGS BEGIN A LITTLE EARLIER IN THE
SOUTHERN COUNTIES AND THUS BEGAN LOW CHANCES WITH THEM IN THE
MORNING. ANOTHER NOTE...ACROSS THE NORTH IN THE AFTERNOON AS THE
PRECIPITATION STARTS FORECAST SOUNDINGS ARE SHOWING THE WARM AIR
ARRIVING A LITTLE LATER THAN PREVIOUS RUNS. IF THIS HOLDS TRUE COULD
SEE A BRIEF PERIOD OF SNOW OR A RAIN/SNOW MIX TO BEGIN WITH BEFORE
CHANGING OVER TO ALL RAIN. HAVE INCLUDED A CHANCE OF SNOW WITH
LIKELY RAIN IN THE NORTHERN THIRD OF COUNTIES TO ACCOUNT FOR THIS.
AS THE WARMING RAMPS UP THOUGH THINGS WILL WIND UP BEING ALL RAIN
AND THUS DO NOT EXPECT ANY SNOW ACCUMULATION. BY TUESDAY NIGHT THE
FORCING ACROSS THE ENTIRE AREA IS SIGNIFICANT...WITH A GREAT
COMBINATION OF ISENTROPIC LIFT AND UPPER LEVEL Q VECTOR CONVERGENCE.
A LOW LEVEL JET POINTS TOWARD INDIANA AND PRECIPITABLE WATER VALUES
RISE TO AROUND 200 PERCENT OF NORMAL. THIS SHOULD LEAD TO DECENT
RAINFALL AMOUNTS ACROSS THE AREA...PERHAPS AROUND AN INCH WITH SOME
HEAVIER POCKETS. WITH NEGATIVELY TILTED TROUGH AND GREAT DYNAMICS
WILL CONTINUE TO KEEP A MENTION OF THUNDER IN THE FORECAST. DESPITE
GREAT SHEAR EXPECT ANY SEVERE THREAT TO REMAIN SOUTH OF THE AREA
GIVEN THE LACK OF WARMER AIR /TEMPERATURES ONLY IN THE 30S-40S/.
WEDNESDAY WILL SEE A CHANGEOVER FROM RAIN TO SNOW. MODEL CONSENSUS
MINUS THE NAM SHOWS COLD AIR ARRIVING BETWEEN 12 AND 18Z SIMILAR TO
PREVIOUS RUNS. WHERE IN THAT SIX HOUR WINDOW CHANGEOVER WILL HAPPEN
IS STILL TOO TOUGH TO PIN DOWN SO WILL LEAVE RAIN OR SNOW WORDING
DURING THAT TIME. BY 18Z ALL PRECIPITATION ACROSS CENTRAL INDIANA
SHOULD HAVE CHANGED OVER TO SNOW. A LOT OF THE FORCING WILL HAVE
MOVED OUT OF THE AREA BY THAT TIME HOWEVER SO LITTLE IS EXPECTED IN
THE WAY OF ACCUMULATIONS.
THE BIGGEST STORY FOR WEDNESDAY APPEARS TO BE THE WINDS. THE SURFACE
LOW IS PROGGED TO STRENGTHEN RAPIDLY AS IT MAKES ITS WAY FROM THE
PLAINS TUESDAY NIGHT THROUGH MICHIGAN WEDNESDAY. A VERY TIGHT
PRESSURE GRADIENT ON THE BACK SIDE OF THIS LOW WILL MOVE THROUGH
CENTRAL INDIANA. WINDS LOOK UNIDIRECTIONAL WITH HEIGHT UP TO 3000 TO
5000 FT AND THIS COULD MIX WINDS OF 40+ KTS /SOME MODELS HIGHER THAN
50/ DOWN TO THE SURFACE PRODUCING WIND GUSTS OF OVER 40 MPH AND
POSSIBLY REACHING 60 MPH. WITH POTENTIAL FOR HIGHER GUSTS WILL GO
AHEAD AT THIS TIME AND ISSUE A HIGH WIND WATCH FOR THE DAY.
WEDNESDAY NIGHT COULD SEE SNOW SHOWERS HANG AROUND IN THE NORTHEAST
COUNTIES FROM SOME WRAPAROUND BUT LITTLE EXPECTED FOR ACCUMULATIONS.
DRY WEATHER EXPECTED THURSDAY WITH COLD TEMPERATURES.
FOR TEMPS...FOR TONIGHT GUIDANCE TEMPERATURES ARE CLOSE WITH THE MAV
A LITTLE BIT WARMER. WITH THE CLOUD COVER AND WARM ADVECTION
STARTING STUCK WITH THE WARMER MAV. FOR HIGHS TUESDAY WENT A BIT
ABOVE GUIDANCE CONSIDERING THE WARM ADVECTION.
&&
.LONG TERM...AS FOR THE EXTENDED...A LARGE AREA OF HIGH PRESSURE
WILL SETTLE OVER THE EASTERN UNITED STATES FOR FRIDAY AND
SATURDAY...PROVIDING SOUTHERLY SURFACE FLOW. WARM AIR ADVECTION ON
SATURDAY SHOULD PROVIDE AN INCREASE IN MIDDLE AND UPPER LEVEL
CLOUDS...BUT WITH A LACK OF UPPER SUPPORT AND STRONG FORCING...WILL
KEEP THE FORECAST DRY FOR NOW.
THE TAIL OF A COLD FRONT WILL QUICKLY PUSH THROUGH THE WESTERN GREAT
LAKES ON SUNDAY PUSHING ACROSS INDIANA ON SUNDAY NIGHT. BEST
FORCING WITH THAT SYSTEM IS WELL TO THE NORTHEAST...OVER ONTARIO
AND QUEBEC...THUS WL ONCE AGAIN KEEP THE FORECAST DRY FOR NOW. WEAK
HIGH PRESSURE SHOULD BE IN PLACE ON MONDAY...KEEPING THINGS DRY.
GIVEN THE EXPECTED H8 TEMPERATURES AND THE LACK OF STRONG ADVECTION
HAVE STAYED CLOSE TO MEXMOS FOR DAILY HIGHS AND LOWS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WATCH FROM WEDNESDAY MORNING THROUGH LATE WEDNESDAY
NIGHT FOR INZ021-028>031-035>049-051>057-060>065-067>072.
&&
$$
UPDATE...JH
AVIATION...MK
PUBLIC...CP
