FXUS63 KIND 092325
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
625 PM EST WED DEC 9 2009
.AVIATION...DISCUSSION FOR THE 10/00Z TAFS.
SCATTERED SNOW SHOWERS AND FLURRIES CONTINUE ACROSS CENTRAL INDIANA
THIS EVENING...ALONG WITH GUSTY WINDS...ON THE BACK SIDE OF INTENSE
LOW PRESSURE OVER THE GREAT LAKES. THE LOW WILL MOVE AWAY TO THE
NORTHEAST OVERNIGHT...WITH WESTERLY WIND GUSTS SLOWLY DIMINISHING TO
25 TO 30KTS. SUBTLE UPPER LEVEL DISTURBANCES CONTINUE TO ROTATE
AROUND THE BACK SIDE OF THE LOW...AND THIS IS CONTRIBUTING TO THE
CONTINUATION OF SNOW SHOWERS AND FLURRIES. STRONGER UPPER LEVEL
SHORT WAVE WILL MOVE ACROSS CENTRAL INDIANA BY 06Z...WITH RIDGING
DEVELOPING THEREAFTER. FEEL IT IS QUITE POSSIBLE THAT LIGHT SNOW
SHOWERS/FLURRIES WILL PERSIST UNTIL THIS PASSES...ESPECIALLY OVER
NORTHERN FORECAST AREA. HAVE HELD ONTO P6SM -SHSN FOR THE FIRST FEW
HOURS OF THE FORECAST. VISIBILITIES MAY BE REDUCED FOR BRIEF PERIODS
IN SNOW SHOWERS...ESPECIALLY AT KLAF.
APPEARS CEILINGS MAY SLIDE BACK BELOW 2000FT IN WAKE OF THE SHORT
WAVE PASSAGE LATE TONIGHT...AND HAVE INTRODUCED A PERIOD OF LOW MVFR
THROUGH EARLY THURSDAY MORNING. HIGH PRESSURE WILL SLOWLY BUILD INTO
THE REGION ON THURSDAY...WITH STRATOCUMULUS BREAKING OUT INTO A
CUMULUS FIELD. CEILINGS WILL LIFT BACK UP INTO VFR CATEGORY AS DRIER
AIR MIXES THROUGH THE LOW LEVELS. WINDS WILL REMAIN GUSTY FROM THE
WEST AT 25 TO 30KTS...GRADUALLY WEAKENING LATE IN THE DAY AS THE
SURFACE PRESSURE GRADIENT RELAXES.
&&
.DISCUSSION...
FORECAST FOCUS IS ON WINDS AND TEMPERATURES IN THE SHORT TERM.
AT 18Z A 975MB LOW WAS LOCATED ACROSS NORTHERN LOWER MICHIGAN.
SCATTERED SNOW SHOWERS WERE WRAPPING AROUND THIS LOW ACROSS THE
FORECAST AREA. DUE TO THE STRENGTH OF THE LOW...SURFACE WINDS WERE
STRONG ACROSS THE AREA...WITH GUSTS WELL OVER 40 MPH COMMON.
TEMPERATURES TO THE WEST AND SOUTHWEST OF INDIANA WERE IN THE TEENS
AND 20S.
MODELS ARE IN DECENT AGREEMENT OVERALL THROUGH THE FIRST FEW DAYS SO
WILL USE A BLEND. IN THE EXTENDED UNCERTAINTY INCREASES RAPIDLY WITH
GFS ENSEMBLE MOS SHOWING 4 TO 5 STANDARD DEVIATIONS FOR
TEMPERATURES. WITH NO REAL FAVORITE IN MODELS...WILL STICK CLOSE TO
HPC EXTENDED GUIDANCE FOR MOST ITEMS FROM DAY 4 /SUNDAY/ ON.
SURFACE LOW WILL CONTINUE TO SLOWLY PULL AWAY FROM THE AREA TONIGHT.
THIS WILL KEEP GUSTY WINDS AROUND DURING THE EVENING. BUFKIT SHOWS
35-40KT GUSTS MAINLY DURING THE EARLY EVENING HOURS ACROSS THE AREA.
THUS EXPECT WINDY CONDITIONS TO CONTINUE EARLY ON. ALTHOUGH WINDS
MAY DROP TO BELOW ADVISORY CRITERIA BEFORE 06Z...WOULD RATHER KEEP
ADVISORY AS IS AND LET EVENING SHIFT CANCEL EARLY THAN TRY TO PIN
DOWN TIMING NOW AND RISK CUTTING IT TOO EARLY. THUS WILL LEAVE
ADVISORY AS IS. EVEN THOUGH WINDS WILL BE BELOW CRITERIA...THEY WILL
STILL BE GUSTY.
NAM 2 METER /2M/ TEMPERATURES ARE DOING A PRETTY GOOD JOB THIS
AFTERNOON. THESE NUMBERS LOOK BETTER THAN THE WARMER MAV
TEMPERATURES FOR LOWS TONIGHT GIVEN UPSTREAM TEMPERATURES. MET LOW
TEMPERATURES ARE EVEN COOLER THAN NAM 2M READINGS. SINCE THE 2M
TEMPERATURES ARE DOING WELL...WILL GO CLOSER TO THESE NUMBERS FOR
LOWS. THESE ARE WELL BELOW AVERAGE AND MAINLY IN THE 10 TO 15 DEGREE
RANGE. COMBINED WITH THE AFOREMENTIONED WINDS...WIND CHILL
TEMPERATURES WILL BE BELOW ZERO FOR MUCH OF THE AREAS. WILL CONTINUE
TO HIGHLIGHT IN THE HWO.
A WEAK WAVE IN THE UPPER FLOW COULD PRODUCE SOME SCATTERED SNOW
SHOWERS ACROSS THE NORTHERN AREA THIS EVENING WITH FLURRIES POSSIBLE
MOST OTHER AREAS. NO ACCUMULATIONS ARE EXPECTED.
ON THURSDAY...BRISK AND COLD CONDITIONS WILL CONTINUE...WITH MAXIMUM
APPARENT TEMPERATURES ONLY REACHING ZERO ACROSS FAR NORTHERN
SECTIONS OF THE AREA. MAV TEMPERATURES LOOK TOO WARM GIVEN THE
STRENGTH OF THE COLD AIR...SO WENT CLOSER TO THE MET/NAM 2M NUMBERS
FOR HIGHS. CLOUDS WILL GIVE WAY TO SUN DURING THE MORNING.
TEMPERATURES THEN MODERATE INTO THE WEEKEND WITH HIGH PRESSURE IN
CONTROL. THE AREA MAY GET CLIPPED BY A SYSTEM MOVING ACROSS THE
SOUTHEAST USA ON SATURDAY NIGHT...SO INCLUDED SMALL POPS THEN. A
COLD FRONT WILL IMPACT THE AREA IN THE SUNDAY NIGHT INTO MONDAY
NIGHT TIME FRAME...SO CONTINUED LOW POPS THEN AS WELL.
&&
.AVIATION...DISCUSSION FOR 18Z TAFS
MAIN AREA OF SNOW SHOWERS HAS MOVED PAST TAFS SITES AND VISIBILITIES
SHOULD IMPROVE QUICKLY TO 6 MILES OR BETTER BY 22Z. BRIEF IFR
VISIBILITIES ARE STILL POSSIBLE FOR ANOTHER HOUR OR TWO...MAINLY
FROM INDY AND NORTHWARD.
WIND GUSTS UP TO 45 KNOTS WILL CONTINUE TO 22Z AND THEN GRADUALLY
DIMINISH OVERNIGHT AS VERY STRONG LOW PRESSURE OVER NORTHERN LOWER
MICHIGAN CONTINUES MOVING NORTHEAST. WIND LATE TONIGHT AND THURSDAY
WILL BE FROM THE WEST AT 15 KNOTS AND OCCASIONAL GUSTS TO 25 KNOTS.
FINALLY MVFR CIGS WILL BE THE RULE THIS AFTERNOON AND TONIGHT.
MODEL SOUNDINGS INDICATE CLOUDS MAY SCATTER OUT AFTER 12Z THURSDAY
AS HIGH PRESSURE BUILDS FROM THE CENTRAL PLAINS INTO THE MID
MISSISSIPPI VALLEY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 1 AM EST THURSDAY FOR INZ021-028>031-035>049-
051>057-060>065-067>072.
&&
$$
PUBLIC...CS
AVIATION...RYAN
