000
FXUS63 KIND 211706
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
106 PM EDT TUE MAY 21 2013

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

&&

.SYNOPSIS...
ISSUED AT 436 AM EDT TUE MAY 21 2013

LARGE LOW PRESSURE SYSTEM OVER THE NORTHERN PLAINS/UPPER MIDWEST
CONTINUES TO DRIFT SLOWLY EASTWARD...AND WILL CONTINUE TO BRING
UNSETTLED WEATHER TO THE AREA THROUGH THURSDAY. HIGH PRESSURE WILL
BUILD INTO THE AREA AS THE WEEKEND APPROACHES.

&&

.NEAR TERM /REST OF TODAY/...
ISSUED AT 1025 AM EDT TUE MAY 21 2013

EARLIER ACTIVITY HAS JUST ABOUT MOVED OUT OF THE LOCAL AREA. AIR
MASS OVER THE PAST COUPLE OF HOURS HAS BEGUN TO DESTABILIZE FAIRLY
RAPIDLY AGAIN...ALTHOUGH LAST NIGHT/S ACTIVITY HAS PUSHED THE MAIN
INSTABILITY AXIS WELL OFF TO THE SOUTHEAST. STEEP LAPSE RATES AND
GOOD DEEP LAYER SHEAR REMAIN.

DON/T REALLY SEE ANY KIND OF REAL FOCUS FOR CONVECTION THE REST OF
THE DAY...OTHER THAT A POSSIBLE MVC COMING OUT OF THE CONVECTION
OVER SOUTHEAST MISSOURI. THIS MAY MOVE OVER SOUTHERN INDIANA LATER
THIS AFTERNOON...POTENTIALLY ENHANCING CONVECTION IN THAT AREA. WILL
KEEP CHANCE POPS GOING FOR THE REST OF THE DAY...HIGHEST IN THE
SOUTH AND SOUTHEAST.

QUITE A BIT OF THICKER CLOUD COVER UPSTREAM THIS MORNING...AND THIS
MAY EVENTUALLY SLOW THE TEMPERATURE RISE THIS AFTERNOON SOME. AS A
RESULT...WILL NUDGE THE HIGHS DOWN A BIT...ESPECIALLY OVER THE SOUTH.

PREVIOUS DISCUSSION FOLLOWS.

LARGE MCS MOVED THROUGH THE AREA OVERNIGHT AND HAS RAPIDLY
WEAKENED AND DISSIPATED OVER THE LAST HOUR OR SO. TRAILING
STRATIFORM SHOWERS/ISOLATED THUNDER ASSOCIATED WITH THE SOUTHERN
PORTION OF THE COMPLEX MAY CONTINUE TO IMPACT PARTS OF THE
FORECAST AREA REMAINDER OF THE NIGHT AND INTO THE MORNING HOURS.
APPEARS LIKELY THAT THINGS MAY CALM DOWN DURING THE MORNING AND
RAMP BACK UP AGAIN LATER THIS AFTERNOON AND INTO THE OVERNIGHT.
HAVE ATTEMPTED TO DEPICT THIS IN POPS WITH MINIMUM NUMBERS LATE
MORNING AND NUMBERS INCREASING LATE THIS AFTERNOON.

ON TEMPS...WITH CLOUD TOPS COOLING AND STORMS DISSIPATING...EXPECT
THAT AT LEAST SOME SUNSHINE WILL BREAK THROUGH LATER THIS MORNING
AND INTO THE AFTERNOON. WITH ANY SUNSHINE...TEMPS SHOULD BE ABLE
TO RAPIDLY CLIMB...SO WILL LEAN TO WARM SIDE OF GUIDANCE AND
EXPECT HIGHS BACK IN THE 80S AGAIN. IF CLOUD COVER IS THICKER OR
MORE PERSISTENT THAN EXPECTED...THIS COULD BE TOO WARM.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
ISSUED AT 436 AM EDT TUE MAY 21 2013

GUIDANCE DEPICTS DEVELOPMENT OF A SECONDARY SURFACE LOW TO OUR
WEST THIS EVENING ALONG FRONTAL BOUNDARY...AND THIS SHOULD HELP
SET THE STAGE FOR PERHAPS ANOTHER ORGANIZED ROUND OF THUNDERSTORMS
THIS EVENING INTO TONIGHT. GIVEN EXPECTED DYNAMIC SUPPORT AND
CONTINUED WARM MOIST AIRMASS IN PLACE...SLIGHT RISK AGAIN APPEARS
VERY REASONABLE.

ORGANIZED STORMS COULD PERSIST INTO MIDDAY WEDNESDAY BEFORE GIVING
WAY TO MORE SHOWERS/ISOLATED THUNDER WEDNESDAY NIGHT. UPPER LOW
WILL MOVE THROUGH THE AREA THURSDAY INTO THURSDAY EVENING...AND
SHOWERS WILL BE POSSIBLE. WILL NOT INCLUDE THUNDER AT THIS TIME AS
FORECAST SOUNDINGS DEPICT VERY WEAK AND SHALLOW INSTABILITY.

ON TEMPS...CONSENSUS NUMBERS APPEARED FINE ON LOWS...BUT APPEARED
TOO COOL AT TIMES ON HIGHS...ALTHOUGH THIS IS ACKNOWLEDGED AS A
LOW CONFIDENCE AREA OF THE FORECAST WITH MAJOR POTENTIAL FOR
CONVECTION TO DISRUPT THESE EXPECTATIONS.

&&

.LONG TERM /FRIDAY THROUGH MONDAY NIGHT/...
ISSUED AT 314 AM EDT TUE MAY 21 2013

GENERALLY DRY WEATHER IS ANTICIPATED DURING THIS PERIOD AS ENSEMBLES
AGREE IN BUILDING A LARGE SURFACE HIGH ACROSS THE REGION. THIS WILL
RESULT IN DRY WEATHER WITH TEMPS AT OR BELOW SEASONABLE NORMALS DUE
TO THE COOL CANADIAN AIR FOR THE BEGINNING OF THE PERIOD. TEMPS WILL
GRADUALLY WARM ON SUNDAY AND SOME OF THE MODELS...NOTABLY THE GFS
DEPICT A WEAK UPPER LEVEL DISTURBANCE MAKING ITS INTO CENTRAL
INDIANA FROM THE NW SUNDAY AND SUNDAY NIGHT...WHICH COULD POSSIBLY
BRING SHOWERS AND THUNDERSTORMS TO THE AREA. NOT VERY CONFIDENT IN
THIS..SO ONLY INCLUDED A SLIGHT CHANCE OF THUNDERSTORMS DURING THIS
TIME.  EARLY NEXT WEEK THE RIDGE PROGRESSES EASTWARD AND
WARMER...MORE HUMID AIR ARRIVES ON SOUTHERLY WINDS ON THE BACK OF
THE RIDGE.

&&

.AVIATION /DISCUSSION FOR THE 211800Z IND TAFS/...

ISSUED AT 1244 PM EDT TUE MAY 21 2013

VFR CONDITIONS ARE EXPECTED FOR MUCH OF THIS TAF PERIOD.

FORECAST SOUNDINGS SHOWS A MOIST AND STILL CONVECTIVELY UNSTABLE
ATMOSPHERE IN PLACE ACROSS CENTRAL INDIANA WITH STEEP LAPSE
RATES...LITTLE CAPPING AND CONVECTIVE TEMPERATURES IN THE UPPER
70S. THUS DIURNAL SCT SHRA OR TSRA WILL BE EXPECTED LATE THIS
AFTERNOON AND EARLY EVENING BEFORE DYING OUT AFTER SUNSET.

GFS AND ECMWF SHOW A STRONG SHORT WAVE AND ASSOCIATED LIFT PUSHING
INTO INDIANA AGAIN OVERNIGHT FROM THE SOUTHWEST. TOO SOON FOR
PRECISE TIMING...THUS WILL USE A VCTS WINDOW FOR NOW. BRIEF MVFR
CONDITIONS WILL BE POSSIBLE AT ANY TAF SITE THAT IS STRUCK BY A THUNDERSTORM.

&&

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

$$

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

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