Special Weather Statement, NWS Indianapolis, IN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1034 AM EDT FRI SEP 7 2012

.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...

ISSUED AT 335 AM EDT FRI SEP 7 2012

A STRONG UPPER TROUGH OVER THE UPPER MIDWEST WILL ROTATE ACROSS OUR
REGION BY SATURDAY.  THIS WILL CAUSE A COLD FRONT FROM THE CENTRAL
PLAINS TO WISCONSIN TO STRENGTHEN AS IT MOVES OUR WAY BY TONIGHT.
MODELS ALSO DEVELOP A LOW PRESSURE SYSTEM ALONG THE FRONT...AND MOVE
IT ACROSS OUR REGION EARLY TONIGHT AND INTO THE EASTERN GREAT LAKES
ON SATURDAY.  THIS FRONTAL SYSTEM WILL BRING LOCALLY HEAVY RAINFALL
LATER TONIGHT AND EARLY TONIGHT.  A FEW SHOWERS COULD LINGER INTO
SATURDAY MORNING. OTHERWISE...MUCH COOLER AND DRY WEATHER WILL BE
THE RULE THE REST OF THE WEEKEND.

IN THE EXTENDED AN UPPER TROUGH OVER THE ST. LAWRENCE RIVER MOVES ON
TO THE EAST AND WARMER AND DRY WEATHER WILL BE THE RULE AS HIGH
PRESSURE DOMINATES OUR WEATHER AND AN UPPER RIDGE OVER THE CENTRAL
U.S. BUILDS OUR WAY.

&&

.NEAR TERM /REST OF TODAY/...

ISSUED AT 1024 AM EDT FRI SEP 7 2012

1015Z UPDATE...WELL UNLIKE YESTERDAY THERE REMAINS QUITE A BIT OF
UNCERTAINTY WITH REGARD TO THE MODEL TIMING OF THIS SYSTEM. THE
GENERAL CONSENSUS IS THAT THE TIMING HAS SLOWED DOWN
CONSIDERABLY...BY AS MUCH AS 6 HOURS COMPARED TO THIS TIME
YESTERDAY...PUSHING THE BULK OF THE SHOWER/TSRA ACTIVITY UNTIL
LATER THIS EVENING...CLOSER TO 00Z.

IN THE MEANTIME...A COMPLEX OF STORMS DEVELOPED OVER PORTIONS OF
IOWA LAST NIGHT AND AND IS CURRENTLY OVER NE IL AND NW IN. SHORT
TERM GUIDANCE SHOWS THIS ACTIVITY BEING KEPT TO THE NORTH OF THE
AREA...BUT RADAR TRENDS ARE LEADING TO BELIEVE SOME OF THIS WILL
MAKE IT INTO OUR NW/W COUNTIES BY THIS AFTERNOON. HAVE ACCOUNTED
FOR THIS IN THE GRIDS.

IN TERMS OF OTHER GRID COMPONENTS...MADE SOME ADJUSTMENTS TO
SKY/TEMP/DEW PT...MAINLY TO ACCOUNT FOR LATEST TRENDS. PREVIOUS
DISCUSSION FOLLOWS...

THUNDERSTORMS WERE CURRENTLY DEVELOPING ACROSS IOWA...AND PARTS OF
THE CENTRAL PLAINS.  MODELS DISAGREE ON HOW FAST THUNDERSTORMS MOVE
INTO OUR REGION AND THIS COULD HAVE A BIG AFFECT ON TEMPERATURES.
THE GFS AND GEMNH BRING PRECIP QUICKLY INTO OUR REGION...WHILE THE
NAM...MM5 AND RAPID REFRESH MOVE THE IOWA STORMS INTO NORTHERN
INDIANA LATER THIS MORNING AND DON'T BRING MUCH INTO OUR REGION
UNTIL AFTER 21Z.  AS A RESULT WILL GO A LITTLE WARMER MOST AREAS
TODAY AND WILL ONLY KEEP MENTION OF HEAVY RAINFALL ACROSS OUR
NORTHWEST THIS AFTERNOON. WILL MENTION CHANCE POPS ACROSS OUR
NORTHWEST HALF BY LATE MORNING AND HIGH POPS ACROSS OUR NORTHWEST
2/3 BY LATE AFTERNOON WITH CHANCE POPS IN THE SOUTHEAST.

SPC HAS US UNDER A SLIGHT RISK OF SEVERE STORMS THIS AFTERNOON AND
EARLY TONIGHT.  NAM INDICATES MU CAPES OF UP TO 3500 J/KG AND
MODERATE LOW LEVEL SHEAR.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...

ISSUED AT 335 AM EDT FRI SEP 7 2012

FORECAST FOCUS WILL BE ON RAIN AMOUNTS AND CHANCES TONIGHT AS WELL
AS THREAT FOR SEVERE WEATHER.  ALL MODELS INDICATE LOCALLY HEAVY
RAINFALL THIS EVENING WITH SOME AREAS RECEIVING 1 TO 2 INCHES OF
PRECIP AS A COLD FRONT MOVES THROUGH AHEAD OF THE ROTATING UPPER
TROUGH.  MOST OF THE SEVERE WEATHER AND HEAVY RAINFALL WILL BE IN
THE EVENING...THEN PRECIP WILL LESSEN OVERNIGHT AFTER COLD FRONT
MOVES THROUGH.  WILL MENTION SLIGHT CHANCE POPS ACROSS OUR EAST
EARLY SATURDAY PER SREF. WIND GUSTS OF 20 TO 25 KNOTS WILL BE
POSSIBLE SATURDAY AS A PRETTY GOOD PRESSURE GRADIENT WILL BE ACROSS
OUR REGION.

DRY AND COOL WEATHER WILL BE THE RULE DURING REST OF THE SHORT TERM
AS HIGH PRESSURE BUILDS INTO THE NORTHERN PLAINS SATURDAY AND INTO
OUR REGION SUNDAY AND SUNDAY NIGHT.  WILL MENTION CLEARING SKIES
SATURDAY NIGHT AND MOSTLY CLEAR AND COOL WEATHER SUNDAY.

AS FAR AS TEMPERATURES ARE CONCERNED...WENT CLOSE TO A MAV/MET BLEND
MOST AREAS.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...

ISSUED AT 335 AM EDT FRI SEP 7 2012

MODELS ARE IN DECENT AGREEMENT THROUGH THE LONG TERM...SO THE
ALLBLEND INITIALIZATION WAS ACCEPTED.

AN UPPER RIDGE WILL BUILD IN ALOFT DURING THE PERIOD WITH HIGH
PRESSURE AT THE SURFACE. THIS WILL KEEP THE LONG TERM DRY AND ALLOW
FOR GRADUALLY WARMING TEMPERATURES THROUGH THE PERIOD. TEMPERATURES
WILL START OUT BELOW AVERAGE BUT WARM TO ABOVE AVERAGE BY THE END OF
THE PERIOD.

&&

.AVIATION /DISCUSSION FOR THE 071500Z IND TAF UPDATE/...

MORNING MVFR FOG IS EXPECTED TO FINISH BURNING OFF WITHIN THE
NEXT 60 MINUTES AS DIURNAL HEATING CONTINUES. VFR CONDITIONS WILL
RETURN FOR THE NEXT FEW HOURS.

WEAKENING TSRA COMPLEX OVER EAST CENTRAL ILLINOIS WILL CONTINUES
TO PROGRESS EAST-SOUTHEAST AND MAY IMPACT THE IND TAF SITE EARLY
THIS AFTERNOON. ANY TSRA THAT STRIKES A TAF SITE MAY PRODUCE BRIEF
MVFR CONDITIONS. RADAR TRENDS CONTINUE TO INDICATE A DIMINISHING
TREND WITH THIS CONVECTION...HOWEVER THERE HAS BEEN SOME NEWER
DEVELOPMENT ON THE SOUTH SIDE OF THE WEAKENING COMPLEX...CLOSER TO
AREAS THAT ARE RECEIVING MORE HEATING. THIS HAS ALSO AIDED IN
TRENDING PROPAGATION MORE SOUTHEASTERLY.

FOR NOW...WILL KEEP THE TEMPS TSRA MENTION AFTER 18Z...BUT WILL
UPGRADE TO PREVAILING WHEN CONFIDENCE IS HIGHER.

PREVIOUS DISCUSSION BELOW

/DISCUSSION FOR THE 071200Z TAFS/...

ISSUED AT 611 AM EDT FRI SEP 7 2012

LOW CONFIDENCE FORECAST IN SPECIFIC TIMING OF CONVECTION TODAY...BUT
CHANCES FOR THUNDERSTORMS WILL INCREASE THROUGH THE DAY.

FIRST CONCERN IS PATCHY DENSE FOG WHICH HAS BROUGHT KHUF AND KBMG
INTO LIFR AT TIMES THIS MORNING. SIMILAR TO YESTERDAY THIS FOG
SHOULD BURN OFF WITHIN THE FIRST HOUR OR TWO OF THE TAF PERIOD.
KLAF/KIND MAY GET BRIEFLY INTO MVFR BEFORE THE FOG BURNS OFF.

CONVECTION CURRENTLY ACROSS IOWA/NORTHERN ILLINOIS LOOKS TO BRUSH
NEAR KLAF THIS MORNING SO WILL INCLUDE A VCTS THERE. UNCERTAINTY
BEGINS WITH HOW THIS CONVECTION WILL INFLUENCE DEVELOPMENT OF OTHER
CONVECTION LATE THIS MORNING AND THIS AFTERNOON.

HOWEVER AS NOTED ABOVE CHANCES FOR TSRA WILL GENERALLY INCREASE
THROUGH THE DAY...SO SHOWED THIS IN THE TAF. BY 22-24Z TSRA SHOULD
BE WIDESPREAD AND THEN PERSIST INTO THE EVENING. OVERNIGHT TSRA WILL
DIMINISH BUT RAIN MAY HANG ON FOR SEVERAL HOURS.

EXPECT LOW MVFR TO IFR CEILINGS TO DEVELOP OVERNIGHT BEHIND THE
CONVECTION.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

SYNOPSIS...JH
NEAR TERM...JH/SMF
SHORT TERM...JH
LONG TERM....50
AVIATION...50/JP

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1014 AM EDT FRI SEP 7 2012

INZ021-028>031-035>049-051>057-060>065-067>072-081415-
CARROLL-WARREN-TIPPECANOE-CLINTON-HOWARD-FOUNTAIN-MONTGOMERY-
BOONE-TIPTON-HAMILTON-MADISON-DELAWARE-RANDOLPH-VERMILLION-PARKE-
PUTNAM-HENDRICKS-MARION-HANCOCK-HENRY-VIGO-CLAY-OWEN-MORGAN-
JOHNSON-SHELBY-RUSH-SULLIVAN-GREENE-MONROE-BROWN-BARTHOLOMEW-
DECATUR-KNOX-DAVIESS-MARTIN-LAWRENCE-JACKSON-JENNINGS-
1014 AM EDT FRI SEP 7 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL INDIANA.

.DAY ONE...TODAY AND TONIGHT.

OUTLOOK: NUMEROUS THUNDERSTORMS WILL OCCUR THIS AFTERNOON AND
TONIGHT...SOME WITH HEAVY RAINFALL. IN ADDITION THERE IS A SLIGHT RISK
OF SEVERE THUNDERSTORMS WITH THE MAIN THREAT BEING DAMAGING WINDS
AND LARGE HAIL. AN ISOLATED TORNADO AND MINOR FLOODING IS ALSO
POSSIBLE.

HAZARDS: THUNDERSTORMS...DAMAGING WINDS...LARGE HAIL...ISOLATED
TORNADOES...LIGHTNING...MINOR FLOODING.

TIMING: THIS AFTERNOON AND EARLY TONIGHT.

DISCUSSION: A COLD FRONT WILL MOVE INTO OUR REGION EARLY TONIGHT
AND NUMEROUS THUNDERSTORMS WILL DEVELOP AHEAD OF THIS COLD FRONT.
THE COMBINATION OF A VERY UNSTABLE AIR MASS...MODERATE LOW LEVEL
SHEAR AND HIGH PRECIPITABLE WATER WILL PRODUCE THE SLIGHT RISK OF
SEVERE WEATHER ALONG WITH HEAVY RAINFALL.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

OUTLOOK: NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

DISCUSSION: A FEW SHOWERS ARE POSSIBLE EARLY SATURDAY.
OTHERWISE...DRY AND COOL WEATHER WILL OCCUR THROUGH EARLY NEXT
WEEK FOLLOWED BY WARMER WEATHER BY THE MIDDLE OF NEXT WEEK.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EARLY TONIGHT.

&&

MORE INFORMATION...ALONG WITH OTHER WEATHER...HYDROLOGICAL AND
CLIMATE INFORMATION CAN BE FOUND...AT HTTP://WEATHER.GOV/IND (ALL
LOWERCASE)

JH

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
622 AM EDT FRI SEP 7 2012

INZ039>045-048-049-051>057-060>065-067>072-071230-
HAMILTON-MADISON-DELAWARE-RANDOLPH-VERMILLION-PARKE-PUTNAM-
HANCOCK-HENRY-VIGO-CLAY-OWEN-MORGAN-JOHNSON-SHELBY-RUSH-SULLIVAN-
GREENE-MONROE-BROWN-BARTHOLOMEW-DECATUR-KNOX-DAVIESS-MARTIN-
LAWRENCE-JACKSON-JENNINGS-
INCLUDING THE CITIES OF...ANDERSON...MUNCIE...TERRE HAUTE...
SHELBYVILLE...BLOOMINGTON...COLUMBUS...VINCENNES...BEDFORD...
SEYMOUR
622 AM EDT FRI SEP 7 2012

...AREAS OF PATCHY DENSE FOG EARLY THIS MORNING...

AREAS OF PATCHY DENSE FOG HAVE DEVELOPED THIS MORNING OVER PARTS
OF WEST CENTRAL...SOUTH CENTRAL AND EAST CENTRAL INDIANA. SOME
LOCATIONS THAT WILL BE IMPACTED INCLUDE...TERRE HAUTE...
BLOOMINGTON...GREENSBURG AND RUSHVILLE. VISIBILITIES MAY BE
REDUCED TO A HALF MILE OR LESS IN SOME SPOTS AT TIMES THROUGH 830
AM.

MOTORISTS ARE URGED TO USE EXTRA CAUTION EARLY THIS MORNING AND BE
AWARE FOR BIG CHANGES IN VISIBILITY. FOG WILL LIFT AND DISSIPATE
BY MID MORNING.

JH

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1142 AM EDT FRI SEP 7 2012

INZ021-030-031-038-071630-
CARROLL-CLINTON-HOWARD-TIPTON-
1142 AM EDT FRI SEP 7 2012

...STRONG THUNDERSTORM ADVISORY FOR NORTHERN CLINTON...SOUTHEASTERN
CARROLL...HOWARD AND NORTHERN TIPTON COUNTIES UNTIL 1230 PM EDT...

AT 1139 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING
A STRONG THUNDERSTORM 13 MILES SOUTHWEST OF WALTON...OR 15 MILES
SOUTH OF LOGANSPORT...MOVING EAST AT 45 MPH.

WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THIS STORM.

LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE...
  KOKOMO...
  RUSSIAVILLE...
  INDIAN HEIGHTS...
  SHARPSVILLE...
  GREENTOWN...
  WINDFALL...

THIS STORM MAY INTENSIFY...AND A SEVERE THUNDERSTORM WATCH IS IN
EFFECT FOR THIS AREA. BE CERTAIN TO MONITOR LOCAL RADIO AND TV
STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS...FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.

&&

LAT...LON 4057 8636 4057 8586 4032 8587 4042 8658
      4069 8641 4069 8637
TIME...MOT...LOC 1542Z 274DEG 37KT 4054 8639

KOCH

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1206 PM EDT FRI SEP 7 2012

INZ030-038>040-071645-
CLINTON-HAMILTON-MADISON-TIPTON-
1206 PM EDT FRI SEP 7 2012

...STRONG THUNDERSTORM ADVISORY FOR EASTERN CLINTON...NORTHEASTERN
HAMILTON...WESTERN MADISON AND TIPTON COUNTIES UNTIL 1245 PM EDT...

AT 1203 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING
A STRONG THUNDERSTORM 12 MILES EAST OF FRANKFORT...MOVING EAST AT 35
MPH.

WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THIS STORM.

LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE...
  TIPTON...
  ELWOOD...
  KEMPTON...
  ATLANTA...
  ARCADIA...

THIS STORM MAY INTENSIFY...AND A SEVERE THUNDERSTORM WATCH IS IN
EFFECT FOR THIS AREA. BE CERTAIN TO MONITOR LOCAL RADIO AND TV
STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS...FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.

&&

LAT...LON 4039 8631 4039 8628 4038 8628 4038 8624
      4031 8574 4009 8583 4027 8638 4039 8632
TIME...MOT...LOC 1607Z 287DEG 30KT 4032 8625

KOCH