Special Weather Statement, NWS Indianapolis, IN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
603 AM EDT THU APR 9 2015

.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 309 AM EDT THU APR 9 2015

A COLD FRONT IS EXPECTED TO MOVE THROUGH THE AREA TONIGHT. IN THE
WAKE OF THIS FRONT...HIGH PRESSURE WILL MOVE INTO THE AREA OVER THE
WEEKEND. ANOTHER FRONTAL SYSTEM MAY AFFECT THE AREA EARLY NEXT WEEK.

&&

.NEAR TERM /TODAY AND TONIGHT/...
ISSUED AT 309 AM EDT THU APR 9 2015

SURFACE WAVE CURRENTLY LOCATED OVER FAR NORTHWEST INDIANA...WITH A
WELL DEFINED OUTFLOW PUSHING THROUGH THE WESTERN ZONES. THIS OUTFLOW
CURVES BACK ACROSS THE SOUTHERN TIP OF ILLINOIS...AND THEN BACK INTO
MISSOURI. SCATTERED CONVECTION DEVELOPING OVER THE EASTERN ZONES
AHEAD OF OUTFLOW...WHILE REMNANTS OF EARLIER CONVECTION OVER
ILLINOIS WAS MOVING INTO WESTERN INDIANA AND WEAKENING.

MOST OF THE SHORT TERM GUIDANCE SUGGESTS CONVECTION WILL DEVELOP INTO
WESTERN INDIANA AROUND DAYBREAK AS A 40 KT LOW LEVEL JET INTERACTS
WITH THE RETREATING OUTFLOW BOUNDARY. STARTING TO SEE CONVECTION
DEVELOP AGAIN OVER WESTERN ILLINOIS...SO THIS MAY BE THE BEGINNING
OF THAT. UPPER AIR FROM LAST EVENING STILL SHOWS RATHER STEEP LAPSE
RATES OVER THE AREA...BUT NOT AS STEEP AS YESTERDAY AS THE AIR MASS
HAS BEEN WORKED OVER SOMEWHAT. STILL APPEARS A THREAT FOR HAIL WITH
ANY DEEP CONVECTION THAT DEVELOPS LATER THIS MORNING.

MAY BE A RELATIVE LULL FOR A TIME THIS AFTERNOON AS ANY MORNING
CONVECTION MOVES OFF TO THE NORTHEAST AND MAIN FORCING WITH APPROACHING
COLD FRONT BEGINS TO ARRIVE TOWARDS EVENING. SCATTERED CONVECTION
MAY DEVELOP THIS AFTERNOON ALONG THE RETREATING OUTFLOW OR IN THE
WARM SECTOR AS AIR MASS IS ONLY WEAKLY CAPPED. LOW LEVEL HELICITY
MAY BE ENHANCED IN THE VICINITY OF ANY CELLS THAT DEVELOP THIS
AFTERNOON NEAR ANY RESIDUAL BOUNDARIES. APPEARS BEST THREAT FOR
SEVERE STORMS WILL BE THIS EVENING AND TONIGHT AS DEEP LAYER SHEAR
INCREASES WITH THE APPROACH OF THE MID LEVEL JET CORE. THE THREAT
MAY TRANSITION TO MORE OF A HIGH WIND THREAT THIS EVENING AS LAPSE
RATES MAY TAIL OFF SOME BY THEN.

WILL GO WITH HIGH POPS FOR TODAY AND MOST OF TONIGHT UNTIL FRONTAL
PASSAGE DURING THE EARLY MORNING HOURS OF FRIDAY. SEVERE THREAT
SHOULD END WITH THE FRONTAL PASSAGE.

PRECIPITABLE WATERS REMAIN HIGH UNTIL FRONTAL PASSAGE...SO THE
THREAT FOR HEAVY RAIN AND FLOODING WILL CONTINUE UNTIL THEN. WILL
EXTEND THE FLASH FLOOD WATCH THROUGH MOST OF TONIGHT.

LOOKING AT LOW LEVEL THICKNESSES...DON/T HAVE TOO MUCH OF A PROBLEM
WITH THE GFS MOS HIGHS TODAY. CONSIDERING THE SPEED OF THE COLD
FRONT TONIGHT AND STRENGTH OF COLD ADVECTION BEHIND IT...WILL CUT
THE GUIDANCE LOWS TONIGHT A FEW DEGREES.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
ISSUED AT 309 AM EDT THU APR 9 2015

DRY WEATHER EXPECTED DURING THIS PERIOD WITH HIGH PRESSURE BUILDING
INTO THE AREA. THE GFS MOS HIGHS ON SATURDAY MAY BE A LITTLE WARM
OVER THE SOUTH...BUT OVERALL THE GUIDANCE LOOKS REASONABLE.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
ISSUED AT 326 AM EDT THU APR 9 2015

A NICE START TO THE EXTENDED ON SUNDAY WITH ZONAL FLOW ALOFT AND
SOUTHERLY WINDS AS HIGH PRESSURE SHIFTS OFF TO THE EAST. THE ZONAL
PATTERN ALOFT WILL GRADUALLY TRANSITION TO A MOIST SOUTHWEST FLOW BY
MIDWEEK AS A SOUTHERN STREAM WAVE ALOFT TRACKS THROUGH THE REGION
AND BECOMES ABSORBED BY AN EXPANDING UPPER TROUGH FROM THE NORTHWEST
BY THE END OF THE PERIOD. THIS WILL RESULT IN A RESUMPTION OF
UNSETTLED WEATHER FOR MUCH OF NEXT WEEK.

DRY WEATHER IS EXPECTED SUNDAY WITH INCREASING CLOUDS AHEAD OF A
WEAK COLD FRONT. THE FRONT WILL TRACK THROUGH THE REGION SUNDAY
NIGHT AND MONDAY DRAWING GULF MOISTURE NORTH INTO THE OHIO VALLEY.
THIS WILL BRING SHOWERS AND THUNDERSTORMS THROUGH CENTRAL INDIANA.
RECENT EXTENDED MODEL RUNS NOW PUSHING THE FRONT FURTHER SOUTH MONDAY
NIGHT WITH WEAK HIGH PRESSURE BUILDING INTO THE GREAT LAKES DUE TO
THE SLOWER EJECTION OF THE UPPER WAVE OUT OF BAJA CALIFORNIA.
HESITATE TO COMPLETELY REMOVE POPS FOR MONDAY NIGHT AND EARLY
TUESDAY JUST YET...BUT THERE IS GROWING CONSENSUS AMONG THE MODEL
SOLUTIONS FOR BULK OF THE PRECIP REMAINING SOUTH OF THE FORECAST
AREA DURING THIS TIMEFRAME.

AS THE UPPER WAVE MOVES INTO THE CENTRAL PLAINS TUESDAY...SHOWERS
AND THUNDERSTORMS WILL INCREASE IN COVERAGE AS THE BOUNDARY RETURNS
NORTH AS A WARM FRONT. WILL MAINTAIN CHANCE POPS THROUGH THE
REMAINDER OF THE EXTENDED AS THE WARM FRONT LIFTS INTO THE LOWER
GREAT LAKES.

SEASONABLE TEMPS ARE EXPECTED THROUGHOUT THE PERIOD...WITH HIGHS IN
THE 60S AND LOWER 70S THROUGH TUESDAY. WITH THE WARM FRONT LIFTING
NORTH OF THE AREA WEDNESDAY...HIGHS IN THE 70S ARE EXPECTED ACROSS
THE ENTIRE FORECAST AREA.

&&

.AVIATION /DISCUSSION FOR 091200Z TAF ISSUANCE/...
ISSUED AT 603 AM EDT THU APR 9 2015

SUB-IFR CONDITIONS POSSIBLE WITHIN CONVECTION THROUGH THIS
EVENING...OTHERWISE VFR EXPECTED. MVFR CEILINGS POSSIBLE LATE
TONIGHT.

ANOTHER COMPLEX CONVECTIVE FORECAST TODAY FOR CENTRAL INDIANA. A
WARM FRONT STRETCHES ACROSS NORTH CENTRAL INDIANA EARLY THIS
MORNING WITH S/SW WINDS SOUTH OF THE FRONT. HAVE SEEN AN INCREASE
IN CONVECTIVE COVERAGE FROM CENTRAL ILLINOIS SOUTHWEST INTO
MISSOURI AIDED BY A LOW LEVEL JET AND AN UPPER LEVEL WAVE. HI-RES
GUIDANCE TRACKING THIS CONVECTION INTO THE REGION THIS MORNING...
WITH MOST IMMEDIATE IMPACTS LIKELY AT KLAF. ANTICIPATE KHUF AND
KIND WILL EVENTUALLY BE IMPACTED BY STORMS AS WELL AND POSSIBLY
EVEN KBMG.

SHOULD SEE PRECIP BECOME MORE SCATTERED DURING THE AFTERNOON AS
UPPER WAVE MOVES OFF TO THE EAST AND LOW LEVEL JET WEAKENS. COULD
SEE SCATTERED STORMS IMPACT THE TERMINALS AT ANY TIME THROUGH THE
AFTERNOON...BUT CONFIDENCE TOO LOW TO MENTION AT THIS TIME. THE
MOST SIGNIFICANT IMPACT TO OPERATIONS DURING THE AFTERNOON WILL BE
SYNOPTIC WINDS. S/SW WINDS OVER 20KTS WITH GUSTS AT 30-35KTS ARE
POSSIBLE BY LATE AFTERNOON AS THE GRADIENT TIGHTENS AHEAD OF
STRENGTHENING LOW PRESSURE. THESE WINDS WILL REMAIN GUSTY INTO THE
EVENING.

BEST CHANCE FOR SEVERE WEATHER COMES DURING THE MID/LATE EVENING
AS A SQUALL LINE EXPECTED TO DEVELOP ALONG THE FRONT AND MOVE
THROUGH CENTRAL INDIANA. BEST TIMING ON IMPACTS TO TERMINALS FROM
THIS SQUALL LINE IS 02Z THROUGH 07Z FROM WEST TO EAST. MVFR
STRATUS WILL MOVE INTO THE REGION BEHIND THE FRONT WITH WINDS
VEERING TO WESTERLY AND REMAINING GUSTY.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR INZ021-028>031-
035>049-051>057-060>065-067>072.

&&

SYNOPSIS...JAS
NEAR TERM...JAS
SHORT TERM...JAS
LONG TERM...RYAN
AVIATION...RYAN

VISIT US AT HTTP://WWW.WEATHER.GOV/IND

FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
527 AM EDT THU APR 9 2015

INZ021-028>031-035>049-051>057-060>065-067>072-101000-
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-
527 AM EDT THU APR 9 2015

...FLASH FLOOD WATCH IN EFFECT THROUGH LATE TONIGHT...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL INDIANA.

.DAY ONE...TODAY AND TONIGHT.

OUTLOOK: THERE IS AN ENHANCED RISK FOR SEVERE THUNDERSTORMS ACROSS
CENTRAL INDIANA FOR MAINLY THIS AFTERNOON AND TONIGHT.

SOUTH TO SOUTHWEST WINDS...INDEPENDENT OF CONVECTION...MAY GUST
TO AROUND 35 MPH THIS AFTERNOON AND EVENING.

HAZARDS: DAMAGING WIND GUSTS...LARGE HAIL...CLOUD TO GROUND
LIGHTNING...HEAVY RAINFALL WHICH MAY CAUSE FLASH FLOODING AND
REDUCED VISIBILITY...ISOLATED TORNADOES.

TIMING: BEST THREAT FOR SEVERE STORMS FROM MID AFTERNOON TODAY
INTO THE EARLY MORNING HOURS OF TONIGHT.

DISCUSSION: A COLD FRONT IS EXPECTED TO MOVE THROUGH CENTRAL
INDIANA TONIGHT. PERIODIC THUNDERSTORM ACTIVITY IS EXPECTED AHEAD
AND ALONG THE FRONTAL ZONE TODAY AND TONIGHT. SOME OF THE STRONGER
STORMS THIS MORNING MAY PRODUCE HAIL. THE BETTER THREAT FOR MORE
NUMEROUS SEVERE STORMS WILL DEVELOP FROM THE MID AFTERNOON HOURS
AND LINGER WELL INTO THE NIGHT. DAMAGING WINDS...LARGE
HAIL...FLASH FLOODING...AND ISOLATED TORNADOES ARE POSSIBLE WITH
STORMS THAT DEVELOP LATER THIS AFTERNOON AND TONIGHT.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

OUTLOOK: THUNDERSTORM ACTIVITY IS POSSIBLE EARLY NEXT WEEK...FROM
SUNDAY NIGHT THROUGH NEXT WEDNESDAY. SEVERE STORMS ARE NOT
EXPECTED AT THIS TIME.

RIVER FLOODING IS EXPECTED TO DEVELOP ALONG AREA RIVERS BY THIS
WEEKEND...AND LINGER INTO NEXT WEEK.

DISCUSSION: HIGH PRESSURE WILL BUILD INTO THE AREA DURING THE
WEEKEND. ANOTHER FRONTAL SYSTEM MAY AFFECT THE AREA BY EARLY NEXT
WEEK WITH THE THREAT FOR ADDITIONAL THUNDERSTORM ACTIVITY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED FROM THE MID AFTERNOON HOURS
TODAY INTO TONIGHT.

&&

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

JAS

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
614 AM EDT THU APR 9 2015

INZ028-035-043-091100-
FOUNTAIN-VERMILLION-WARREN-
614 AM EDT THU APR 9 2015

...STRONG THUNDERSTORM ADVISORY FOR NORTHERN FOUNTAIN...NORTHWESTERN
VERMILLION AND WARREN COUNTIES UNTIL 700 AM EDT...

AT 612 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM NEAR CATLIN...OR 8 MILES SOUTHWEST OF DANVILLE...
MOVING NORTHEAST AT 50 MPH.

HAIL UP TO THE SIZE OF NICKELS AND WIND GUSTS UP TO 50 MPH ARE
EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN AND FREQUENT
DANGEROUS LIGHTNING.

LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE...
  COVINGTON...
  WILLIAMSPORT...
  GESSIE...
  FOSTER...
  STATE LINE CITY...
  PENCE...
  WEST LEBANON...
  TAB...
  ATTICA...
  RAINSVILLE...
  PINE VILLAGE...

THIS STORM MAY INTENSIFY...SO 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.

TORRENTIAL RAIN...WHICH MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND
UNDERPASSES...IS ALSO LIKELY. DO NOT DRIVE YOUR VEHICLE ON A FLOODED
ROADWAY.

&&

LAT...LON 4039 8753 4048 8736 4048 8720 4040 8709
      4030 8709 4003 8753
TIME...MOT...LOC 1014Z 230DEG 43KT 4007 8771

RYAN