FXUS63 KIND 091114
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
615 AM EST WED DEC 9 2009
.AVIATION DISCUSSION...FOR THE 12Z TAFS
A MAJOR WEATHER PROBLEM FOR AVIATION TODAY WILL BE EXTREMELY STRONG
WIND. A VERY STRONG LOW PRESSURE SYSTEM WILL MOVE THROUGH THE GREAT
LAKES AREA TODAY. THE VERY TIGHT PRESSURE GRADIENT WILL GIVE WIND
GUSTS UP TO 45 KTS. WIND DIRECTION WILL BE FROM THE SW THIS MORNING
SHIFTING TO THE WEST DURING THE LATE AFTERNOON. MVFR CEILINGS WILL
OCCUR ACROSS THE AREA. SNOW WAS WRAPPING AROUND THE LOW. THIS WILL
MOVE INTO INDIANA LATER IN THE MORNING. THE SNOW SHOULD NOT DECREASE
VSBYS BELOW MVFR LEVELS. AS THE LOW CONTINUES TO PULL NE THE WINDS
WILL DECREASE. BY 04Z WINDSPEEDS WILL ONLY BR AROUND 20 KTS. THE
SNOW WILL MOVE OUT BUT MVFR CEILINGS WILL REMAIN.
&&
.SHORT TERM...
A POWERFUL LOW PRESSURE SYSTEM HAS FINALLY MOVED INTO THE
MIDWEST...AND IS PRODUCING AN ARRAY OF WEATHER FROM THE DEEP SOUTH
TO THE UPPER MIDWEST. SHOWERS AND THUNDERSTORMS HAVE FORMED ALONG
A COLD FRONT STRETCHING FROM THE OHIO VALLEY TO THE GULF OF
MEXICO. FURTHER NORTH...HEAVY SNOW AND STRONG WINDS ARE MOVING
THROUGH THE GREAT LAKES AREA. THE SYSTEM CONTINUES TO DEEPEN WITH
PRESSURE DROPS OF OVER 30 MB.
THE MAIN FOCUS OF FORECAST PERIOD IS THE PRECIPITATION TYPE/TIMING
THIS MORNING AND THE HIGH WINDS.
NO CHANGES WERE MADE TO THE TIMING/TYPE OF PRECIPITATION TODAY.
FORECAST IS STILL ON TRACK FOR RAIN THROUGH THE EARLY MORNING
HOURS AS TEMPERATURES HOLD STEADY IN THE MID 40S THROUGH MID
MORNING. THE WESTERN PORTIONS OF FORECAST AREA COULD STILL SEE A
MIXTURE OF RAIN/SNOW BY LATE MORNING AS COLD AIR BEGINS FILTERING
INTO INDIANA. THE RAIN/SNOW MIX WILL TRANSITION TO ALL SNOW ACROSS
ENTIRE FORECAST AREA AFTER NOON AS TEMPERATURES BEGIN PLUMMETING.
HOWEVER...THERE COULD BE A LULL IN PRECIPITATION BETWEEN THE WED
15Z/18Z TIME FRAME AS ISENTROPIC LIFT SHUTS DOWN AND DRY SLOT
MOVES INTO AREA. HOWEVER...WRAPAROUND MOISTURE WILL MOVE ACROSS
INDIANA AROUND WED 18Z WHEN PRECIPITATION WILL TRANSITION TO ALL
SNOW. SNOW ACCUMULATIONS WILL BE MINIMAL THOUGH AS MOISTURE
QUICKLY MOVES TO THE NORTHEAST.
WINDS ARE CURRENTLY GUSTING TO 40 MPH OVER PORTIONS OF THE AREA.
STILL TORN ON WHETHER TO ISSUE THE HIGH WIND WARNING. THE PRESSURE
GRADIENT AND UPPER LEVEL JET APPEAR TO BE THE STRONGEST JUST SOUTH
OF COUNTY WARNING AREA. BUT...GUSTS ARE ALREADY UP TO 40 MPH AND
WILL GET STRONGER THIS AFTERNOON. WILL MONITOR THIS SITUATION.
DANGEROUS WINDCHILLS ARE STILL EXPECTED THROUGH FRIDAY WITH
TEMPERATURES WELL BELOW ZERO. A WINDCHILL ADVISORY MAY HAVE TO BE
ISSUED AFTER NEW MODELS COME IN. THERE IS TOO MUCH DISCREPANCY
RIGHT NOW TO ISSUE ADVISORY. THE CANADIAN SEEMED TOO COLD
YESTERDAY...BUT THE NAM HAS NOW COME INTO AGREEMENT WITH
IT...LEAVING THE GFS AS THE OUTLIER. TRENDED WELL BELOW GUIDANCE
DUE TO HOW FAST NAM HAS COME INTO AGREEMENT WITH GEM.
HOWEVER...GEM IS STILL ON ITS OWN WITH REGARD TO FRIDAY NIGHT
LOWS...FORECASTING SINGLE DIGITS WHILE OTHER MODELS ARE INDICATING
LOW 20S.
LONG TERM.../FRIDAY THROUGH TUESDAY/
IN THE EXTENDED PERIOD...ARCTIC AIR WILL BE ENTRENCHED ACROSS THE
NORTHERN TIER STATES...WHILE A MOIST AND RATHER ACTIVE PATTERN
OCCURS ACROSS THE SOUTHERN U.S.
ON FRIDAY HIGH PRESSURE WILL MOVE FROM THE OHIO VALLEY TO MID
ATLANTIC STATES. THE EUROPEAN...GEM AND GFS MODELS MOVE AN UPPER
LEVEL DISTURBANCE ACROSS THE DEEP SOUTH LATE FRIDAY AND FRIDAY
NIGHT. THE EUROPEAN BRINGS MOISTURE FROM THIS SYSTEM AS FAR NORTH
AS INDIANA LATE FRIDAY NIGHT AND SATURDAY...WHILE THE GEM...GFS
MODELS KEEP PRECIPITATION SUPPRESSED TO THE SOUTH. HPC WENT CLOSE
TO THE EUROPEAN. BUT WITH THE GEM AND GFS COMING IN DRIER WILL
DOWNPLAY PRECIPITATION A LITTLE.
THIS SOUTHERN SYSTEM MOVES ON TO THE EAST BY SUNDAY. THE EUROPEAN
BRINGS AN UPPER LEVEL DISTURBANCE ACROSS OUR AREA BY MONDAY. BOTH
THE GFS AND GEM SHOW VERY LITTLE MOISTURE NORTH OF THE OHIO
RIVER...SO WILL DOWNPLAY PRECIPITATION CHANCES AGAIN TO A SLIGHT
CHANCE LATER SUNDAY NIGHT AND MONDAY.
THE 12Z GFS DEVELOPS A STRONG UPPER TROUGH ACROSS OUR REGION BY
TUESDAY. IT ALSO TAKES A STRONG SURFACE LOW FROM THE NORTHERN GULF
TO THE MID ATLANTIC STATES AND IN TURN SPREADS PRECIPITATION ACROSS
OUR REGION. I HAVE LOW CONFIDENCE ON THIS AND WILL MENTION SLIGHT
CHANCES OF PRECIPITATION MONDAY NIGHT AND THEN KEEP TUESDAY DRY.
AS FAR AS TEMPERATURES ARE CONCERNED...I TRENDED A FEW DEGREES BELOW
HPC NUMBERS...BUT NOT QUITE AS COLD AS MEX. ON MONDAY NIGHT ...I
WENT SLIGHTLY WARMER THAN HPC TEMPERATURES AS THERE COULD BE QUITE A
BIT OF CLOUDINESS ACROSS OUR REGION.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 1 AM EST THURSDAY FOR INZ021-028>031-035>049-
051>057-060>065-067>072.
&&
$$
SHORT TERM...TDUD
LONG TERM...JH
AVIATION...SH
