Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 261434
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1034 AM EDT TUE MAY 26 2015

.UPDATE...
AVIATION SECTION UPDATED.

&&

.SYNOPSIS...
ISSUED AT 326 AM EDT TUE MAY 26 2015

UNSETTLED CONDITIONS EXPECTED THROUGH THE WORK WEEK AND INTO THE
WEEKEND AS OCCASIONAL UPPER DISTURBANCES MOVE OVER THE
AREA...RESULTING IN PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS.

&&

.NEAR TERM /REST OF TODAY/...
ISSUED AT 1012 AM EDT TUE MAY 26 2015

SHORT WAVE TROUGH CURRENTLY PUSHING THROUGH WESTERN ILLINOIS...WITH
A BROKEN LINE OF SHOWERS AND THUNDERSTORMS ALONG IT. SHORT TERM
MODEL GUIDANCE SUGGESTS THIS WAVE WILL PASS ACROSS THE LOCAL AREA
AROUND 261700Z-262300Z...SO EXPECTING THE HIGHEST PRECIPITATION
POTENTIAL DURING THAT TIME.

THIS MORNING/S UPPER AIR INDICATES MARGINALLY FAVORABLE DEEP LAYER
SHEAR FOR ORGANIZED SEVERE CONVECTION...BUT LAPSE RATES ARE POOR.
LOW LEVEL SHEAR ALSO SOMEWHAT FAVORABLE FOR TORNADO POTENTIAL.
SURFACE WINDS ACROSS EASTERN ILLINOIS/WESTERN INDIANA AHEAD OF UPPER
FEATURE BACKED A BIT AS WELL.

SOME CONCERN THAT HIGHS TODAY ARE NOT WARM ENOUGH...ESPECIALLY IN
THE EAST WHICH IS RELATIVELY CLOUD FREE AT THIS TIME. WILL KEEP THE
PREVIOUS FORECAST HIGHS GOING FOR NOW AND WATCH THE TEMPERATURE
TRENDS.

WIND PROFILERS AND UPPER AIR INDICATES THERE IS STILL ABOUT 35-40
KTS OF FLOW ABOVE 030...SO WILL ADD SOME GUSTS TO THE
FORECAST...ESPECIALLY OVER THE EAST WHERE THE BEST MIXING WILL
OCCUR.

PREVIOUS DISCUSSION FOLLOWS.

THE NEXT UPPER WAVE CURRENTLY APPROACHING NORTHWEST ILLINOIS IS
EXPECTED TO EJECT NORTHEAST ACROSS THE FORECAST AREA BEGINNING LATER
THIS MORNING. IN RESPONSE TO THIS FEATURE...THE LOW LEVEL JET WILL
INCREASE AGAIN TOWARDS DAWN...RESULTING IN ADDITIONAL GUSTY WINDS
TODAY. THIS WAVE WILL PRODUCE RAIN SHOWERS AND THUNDERSTORMS
ACROSS MOST OF CENTRAL INDIANA...WITH THE HIGHEST POPS DEPICTED IN
THE GUIDANCE TO BE ACROSS THE SOUTHWEST COUNTIES OF CENTRAL INDIANA.
BASED ON GOOD MODEL CONSENSUS AND CONSISTENCY LIKELY POPS WILL
REMAIN IN THE FORECAST FOR TODAY. LAPSE RATES/DEEP SHEAR LOOK RATHER
MARGINAL FOR SEVERE CONVECTION...ALTHOUGH MODELS SUGGEST LAPSE RATES
MAY STEEPEN SOME DURING THE AFTERNOON SO ISOLATED SEVERE STORMS
CANNOT BE COMPLETELY RULED OUT.

AS FOR TEMPERATURES...UNDERCUT MOS SLIGHTLY TO ACCOUNT FOR CLOUDS
AND PRECIPITATION CHANCES FOR HIGHS REACHING THE UPPER 70S TO AROUND
80.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...

ISSUED AT 326 AM EDT TUE MAY 26 2015

THIS UNSETTLED PATTERN WILL CONTINUE FOR SCATTERED SHOWERS AND
THUNDERSTORMS INTO AT LEAST MID WEEK AS A SERIES OF UPPER LEVEL
DISTURBANCES RIPPLE THROUGH THE FLOW. WILL CONTINUE WITH CHANCE
POPS FOR WEDNESDAY AND THURSDAY. THE CONVECTIVE THREAT APPEARS
MORE SUPPRESSED ON THURSDAY SO DOWNPLAYED POPS TO 20-30 PERCENT
DURING THE DAY AS HEIGHTS START TO RISE AGAIN...AND DRY BRIEFLY
FOR THURSDAY NIGHT.

MOS BLEND FOR TEMPERATURES APPEARS REASONABLE DURING THIS PERIOD
FOR HIGHS IN THE LOW 80S AND LOWS IN THE MID 60S.

&&

.LONG TERM /FRIDAY THROUGH MONDAY NIGHT/...

ISSUED AT 332 AM EDT TUE MAY 26 2015

A RATHER ACTIVE WEATHER PATTERN WILL BE IN PLACE FOR THE DURATION
OF THE EXTENDED PERIOD. FIRST...CENTRAL INDIANA WILL FALL INTO THE
WARM SECTOR OF A SURFACE LOW CENTERED OVER THE CENTRAL PLAINS ON
FRIDAY. MEANWHILE...HIGH PRESSURE WILL DOMINATE THE SOUTHEAST
PORTIONS OF THE U.S. THIS SET UP WILL BE CONDUCIVE TO DIURNALLY
DRIVEN SHOWERS AND THUNDERSTORMS FOR THE BEGINNING OF THE LONG
TERM PERIOD.

AS A COLD FRONT ASSOCIATED WITH AFOREMENTIONED SURFACE LOW PASSES
OVER THE FORECAST AREA ON SATURDAY...PRECIPITATION CHANCES ARE
EXPECTED TO INCREASE PER THE LATEST REGIONAL INITIALIZATION.

LATE IN THE EXTENDED...A CUT-OFF LOW ALOFT WILL TRACK ACROSS THE
LOWER MIDWEST. THIS WILL PROVIDE ADDITIONAL ENHANCEMENT FOR
SHOWER AND THUNDERSTORM DEVELOPMENT ON MONDAY. LATEST SUPERBLEND
SEEMS A TAD LOW IN REGARD TO PRECIP CHANCES THOUGH WITH THIS
UPPER DISTURBANCE...BUT WILL NOT DEVIATE FROM THOSE NUMBERS AT
THIS TIME.

&&

.AVIATION /DISCUSSION FOR THE 261500Z IND TAF UPDATE/...

BASED UPON RADAR TRENDS AND CONVECTIVE TEMPS EXPECTED TO BE
REACHED IN THE NEXT 1-2 HOURS...HAVE TRENDED PRECIP CHANCES BACK A
FEW HOURS THAN THE PREVIOUS TAF.

TSRA THIS AFTERNOON LOOKS QUITE REASONABLE GIVEN THE APPROACHING
SHORT WAVE ALONG WITH THE FAVORABLE TIMING FOR DAYTIME HEATING.
REST OF THE TAF REMAINS UNCHANGED.

PREVIOUS DISCUSSION BELOW

/DISCUSSION FOR THE 26/1200Z TAF ISSUANCE/...

ISSUED AT 732 AM EDT TUE MAY 26 2015

CONDITIONS ARE CURRENTLY AT MVFR CATEGORY AT ALL TAF SITES AND
SHOULD REMAIN THERE FOR MOST OF THE DAY WITH BRIEF IMPROVEMENT TO
VFR THIS AFTERNOON. ANTICIPATE RAIN TO START ENTERING TAF SITES BY
LATE MORNING WITH A CHANCE FOR STRONG TO SEVERE THUNDERSTORMS THIS
AFTERNOON AND EVENING.

CONVECTIVE THREAT SHOULD TAPER OFF AFTER SUNSET...BUT FOCUS THEN
SHIFTS TO THE CHANCE FOR FOG DEVELOPMENT TONIGHT. INSERTED MENTION
OF IFR AND MVFR FOG AT TAF SITES AFTER WED 09Z...BUT THIS IS LOW
CONFIDENCE AND DEPENDANT ON HOW MUCH PRECIP FALLS AT TAF SITES LATER
TODAY.

WINDS WILL BE SOUTHWESTERLY FOR DURATION OF TAF PERIOD WITH
SUSTAINED SPEEDS GENERALLY BETWEEN 5 TO 10 KTS...GUSTING TO 25
KTS AT TIMES TODAY AND TOMORROW.


&&

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

$$

SYNOPSIS...SMF
NEAR TERM...SMF/JAS
SHORT TERM...SMF
LONG TERM....TDUD
AVIATION...TDUD/JP

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