000
FXUS63 KIND 211014
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
614 AM 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 /TODAY/...
ISSUED AT 436 AM EDT TUE MAY 21 2013

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 211200Z TAF ISSUANCE/...

ISSUED AT 611 AM EDT TUE MAY 21 2013

ATMOSPHERE LIKELY TO DESTABILIZE LATE IN THE DAY WITH MORE
THUNDERSTORM DEVELOPMENT ON TAP. COULD SEE WIND GUSTS TO 40 KNOTS
WITH SUSTAINED WINDS 20 KNOTS FROM THE SOUTHWEST WITHIN THE LINE
OVERNIGHT...BUT STILL HARD TO NAIL DOWN TIMING AT THIS POINT SO
WILL GO WITH VCTS DURING THIS TIME FOR NOW. WINDS GUSTING TO
AROUND 20 KT STARING LATER THIS MORNING.

&&

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

$$

SYNOPSIS...NIELD
NEAR TERM...NIELD
SHORT TERM...NIELD
LONG TERM....SMF
AVIATION...SMF

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

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

000
FXUS63 KIWX 210845
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
445 AM EDT TUE MAY 21 2013

.SYNOPSIS...
ISSUED AT 440 AM EDT TUE MAY 21 2013

SHOWER AND THUNDERSTORM CHANCES WILL CONTINUE TO INCREASE THROUGH
WEDNESDAY...WITH A FEW SHOWERS POSSIBLY LINGERING INTO THURSDAY.
DRIER AND COOLER WEATHER IS ANTICIPATED LATE THIS WEEK INTO NEXT
WEEKEND.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 442 AM EDT TUE MAY 21 2013

OUTFLW DOMINANT CONVN CONTS TO PROGRESS SLOWLY ACRS
WRN PORTION OF CWA THIS MORNING YET CONTS TO FESTER WITHIN AS YET
FVRBLY UNSTABLE LL THETA-E RIDGE. HWVR UPSTREAM STRATIFORM ACRS WRN
IN/ERN IL DECAYING RAPIDLY W/WARMING CLOUD TOPS NOTED IN IR AND
MARKS XPCD RAPID EWD DOWNTREND THROUGH DAYBREAK.

STABILIZATION OCCURRING IN WAKE OF THIS LINE AND SUSPECT LTL IF ANY
REDVLPMNT IN THE CARDS UNTIL VRY LT THIS AFTN/EARLY EVE IN ASSOCN/W
EWD TRANSLATION OF SFC LOW INTO NE WI BY 00Z. HWVR NWD REDVLPMNT OF
PREFERRED LL THETA-E RIDGE LIKELY DELAYED TO WELL AFT DARK TIMED
W/NWD EXPANSION OF LLJ TIED TO EJECTING CONV INDUCED SW TROUGH OUT
OF OK. THUS DELAYED OVERNIGHT RAMP TO PRIOR POPS TWD WINDOW OF
GREATER MODEL CONSENSUS IMPLIED FORCING AFT MIDNIGHT.

INBTWN XPC CLDS TO SCT OUT BY LT MORNING/EARLY AFTN W/ANOTHER VRY
WARM DAY IN STORE PER MODEST MIXING WITHIN LL THERMAL RIDGE.

&&

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 442 AM EDT TUE MAY 21 2013

AN UPPER LOW WILL LIFT NORTHEAST WEDNESDAY...ACCOMPANIED BY A COLD
FRONT. THE RIGHT ENTRANCE REGION OF AN UPPER LEVEL JET WILL PASS
OVER THE SOUTHEAST PORTION OF THE FORECAST AREA WEDNESDAY INCLUDING
MOST OF NW OHIO. HOWEVER...GIVEN VERY LIMITED CAPE AND A RATHER
UNIDIRECTIONAL WIND PROFILE...CURRENT THINKING IS SEVERE STORM
POTENTIAL IS MARGINAL. MUCH COOLER AIR WILL SPREAD INTO THE AREA
BEHIND THE COLD FOR LATE THIS WEEK. FAVORED THE GFS MEAN ENSEMBLE
MOS WHICH HAS BEEN GENERALLY TRENDING A LITTLE COLDER LATE THIS
WEEK...OTHERWISE...HAS BEEN CONSISTENT FOR THE PAST FEW 00Z RUNS.
KEPT THE FORECAST DRY AFTER THURSDAY AS AN UPPER LEVEL RIDGE BUILDS
UPSTREAM.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 442 AM EDT TUE MAY 21 2013


DIFFICULT FORECAST WITH RESPECT TO CONVECTIVE PROBABILITIES THROUGH
THE FORECAST PERIOD AND EARLY FAILURE. AMID A STRONGLY DIVERGENT
BOUNDARY LAYER AXIS PER VIS SAT IMAGERY LYING ACROSS NERN IL/NWRN IN
PAST FEW HOURS PROVING TO BE STRONGLY DETRIMENTAL. THIS DESPITE
MODERATE SURFACE BASED INSTABILITY POOL SITUATED ACROSS NORTHERN
INDIANA/SOUTHERN LOWER MICHIGAN THIS EVENING. A WELL SCOURED/DEEPLY
MIXED ENVIRONMENT ACROSS NORTHERN/CENTRAL ILLINOIS WITH PUTRID
MID/UPR 50S DPS THIS AFTERNOON...REMOVES ANY IMMEDIATE CONCERN FOR
INITIATION NEXT FEW HOURS. THIS IMMEDIATE UPSTREAM ENVIRON WAS
WITHIN WAKE OF EARLY AFTERNOON SHORTWAVE...THAT INITIATED
STRONG/SEVERE CONVECTION MIDDAY ACROSS YOOP/NORTHERN LOWER MICHIGAN.
EASTERN FRINGE OF EML ENVIRONMENT WITH 7.5-8.25 C/KM MID LEVEL LAPSE
RATES TO LIKELY KEEP UPDRAFTS IN CHECK/ISOLATED REMAINDER OF THE
EVENING. WILL MAINTAIN THAT ANY SIG CHANCE FOR CONVECTION TO BE
ASSOCIATED WITH WELL UPSTREAM CONVECTION ACROSS EAST CENTRAL
MO...WITH SEVERAL HOUR WAIT UNTIL MORE VIGORED UPSTREAM 925-8H WIND
FIELD WITH PRESENT FOCUS OVER THE OZARKS/NORTHERN ARKANSAS SHIFTS
NORTHEASTWARD OVERNIGHT INTO SRN/CENTRAL ILLINOIS AND VEERS/RAMPS TO
45-55KTS...FINALLY NOSING INTO KLAF VCNTY AROUND 09-12 UTC PER
RAP/ARW...AND A SIGNIFICANTLY POOR/LAGGARD HRRR3KM RECENTLY COMING
IN LINE TO REALITY. SUFFICIENT PREPARATORY CONDITIONING OF
ENVIRONMENT VIA MOISTURE FLUX CONVERGENCE SFC-900MB TO MAINTAIN
MUCAPE POOL OF 1200-2000 J/KG ACROSS FORECAST AREA. THIS SHOULD
ALLOW DECENT MAINTENANCE OF CONVECTIVE COMPLEX WITH ACROSS MISSOURI
TO REACH NORTHERN INDIANA WELL AFTER MIDNIGHT INTO KSBN AND NEAR
DAYBREAK AT KFWA. DISFAVORED TIMING/PARCEL ASCENT BECOMING LESS
SURFACE BASED WITH TIME AND MODEST DEEP LAYER SHEAR TO LARGELY
PRECLUDE SEVERE POTENTIAL...THOUGH HAVE CONTD TO ACK THAT STRONGEST
CELLS MAY APPROACH LOW END SEVERE LIMITS IN HWO.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...SKIPPER
SHORT TERM...T
LONG TERM...SKIPPER
AVIATION...T


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIND 210845
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
445 AM 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 /TODAY/...
ISSUED AT 436 AM EDT TUE MAY 21 2013

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 210830Z TAF UPDATE/...

ISSUED AT 442 AM EDT TUE MAY 21 2013

WIDESPREAD UPDATES TO ALL THE TAF SITES TO ACCOUNT FOR LINE OF
THUNDERSTORMS HAVING MOVED THROUGH THE AREA. SOME SCATTERED
SHOWERS WILL LINGER OVER THE NEXT FEW HOURS. OTHERWISE VFR
EXPECTED FOR THIS MORNING AND THIS AFTERNOON. PREVIOUS DISCUSSION
FOLLOWS...

RADAR REFLECTIVITY AND RAPID REFRESH REFLECTIVITY PROGS SUGGESTS
LINE OF THUNDERSTORMS...ACROSS ILLINOIS WILL MOVE INTO THE LAF AND
HUF AREAS AROUND 07Z AND IND AND BMG AFTER 08Z. SO...WILL HAVE TEMPO
IFR THUNDERSTORMS THROUGH 11Z AT LAF AND HUF AND 12Z AT IND AND BMG
WITH VCTS FOR A FEW HOURS AFTER AS A BUFFER. THEN...ATMOSPHERE
LIKELY TO DESTABILIZE LATE IN THE DAY WITH MORE THUNDERSTORM
DEVELOPMENT ON TAP ESPECIALLY AFTER 00Z WEDNESDAY. COULD SEE WIND
GUSTS TO 40 KNOTS WITH SUSTAINED WINDS 20 KNOTS FROM THE SOUTHWEST
WITHIN THE LINE OVERNIGHT.

OTHERWISE...POTENTIAL FOR SOUTH AND SOUTHWEST WINDS TO NEAR 20 KNOTS
GUSTING TO NEAR 30 KNOTS AFTER 15Z TODAY AS THE ATMOSPHERE MIXES.

&&

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

$$

SYNOPSIS...NIELD
NEAR TERM...NIELD
SHORT TERM...NIELD
LONG TERM....SMF
AVIATION...KOCH/SMF

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

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

000
FXUS63 KIND 210836
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
436 AM EDT TUE MAY 21 2013

.UPDATE...

THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE 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 /TODAY/...
ISSUED AT 436 AM EDT TUE MAY 21 2013

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 210600Z TAF ISSUANCE/...
ISSUED AT 1215 AM EDT TUE MAY 21 2013

RADAR REFLECTIVITY AND RAPID REFRESH REFLECTIVITY PROGS SUGGESTS
LINE OF THUNDERSTORMS...ACROSS ILLINOIS WILL MOVE INTO THE LAF AND
HUF AREAS AROUND 07Z AND IND AND BMG AFTER 08Z. SO...WILL HAVE TEMPO
IFR THUNDERSTORMS THROUGH 11Z AT LAF AND HUF AND 12Z AT IND AND BMG
WITH VCTS FOR A FEW HOURS AFTER AS A BUFFER. THEN...ATMOSPHERE
LIKELY TO DESTABILIZE LATE IN THE DAY WITH MORE THUNDERSTORM
DEVELOPMENT ON TAP ESPECIALLY AFTER 00Z WEDNESDAY. COULD SEE WIND
GUSTS TO 40 KNOTS WITH SUSTAINED WINDS 20 KNOTS FROM THE SOUTHWEST
WITHIN THE LINE OVERNIGHT.

OTHERWISE...POTENTIAL FOR SOUTH AND SOUTHWEST WINDS TO NEAR 20 KNOTS
GUSTING TO NEAR 30 KNOTS AFTER 15Z TODAY AS THE ATMOSPHERE MIXES.

&&

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

&&

$$

SYNOPSIS...NIELD
NEAR TERM...NIELD
SHORT TERM...NIELD
LONG TERM....SMF
AVIATION...MK

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

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

000
FXUS63 KIND 210714
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
314 AM EDT TUE MAY 21 2013

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

&&

.SYNOPSIS...
ISSUED AT 239 PM EDT MON MAY 20 2013

A LARGE UPPER LOW CURRENTLY OVER THE PLAINS IS EXPECTED TO BRING
UNSETTLED WEATHER TO THE AREA THROUGH THURSDAY AS IT SLOWLY MOVES
EAST AND WEAKENS WITH TIME. IN THE WAKE OF THIS SYSTEM...HIGH
PRESSURE IS EXPECTED TO BUILD INTO THE AREA OVER THE WEEKEND AND
INTO EARLY NEXT WEEK.

&&

.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 835 PM EDT MON MAY 20 2013

CONVECTION ACROSS THE FORECAST AREA HAS CEASED...AND NOW FOCUS IS ON
CONVECTION MOVING INTO ILLINOIS AT THE MOMENT.

CURRENT TIMING ON CONVECTION IN ILLINOIS PUTS IT IN CENTRAL INDIANA
AFTER MIDNIGHT. THUS HAVE REMOVED POPS MOST AREAS UNTIL AFTER
MIDNIGHT...THEN GRADUALLY INCREASED THEM BACK UP TO PREVIOUS
FORECAST. MAY HAVE TO UP THEM INTO LIKELY OR HIGHER CATEGORY LATER
THIS EVENING DEPENDING ON HOW CONVECTION IN ILLINOIS MOVES/DEVELOPS.
RIGHT NOW THE NORTHWEST FORECAST AREA LOOKS TO BE THE AREA WHERE
POPS WOULD HAVE TO BE INCREASED.

DEEP LAYER SHEAR...INITIALLY RATHER WEAK THIS EVENING...IS EXPECTED
TO STRENGTHEN LATER TONIGHT. AS A RESULT...THINK THE POTENTIAL FOR
ORGANIZED SEVERE CONVECTION SHOULD GRADUALLY INCREASE AS TIME GOES
BY TONIGHT. THUS WILL CONTINUE TO MENTION SEVERE THREAT FOR AFTER
MIDNIGHT.

NO CHANGES MADE TO TEMPERATURES AT THIS TIME.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
ISSUED AT 239 PM EDT MON MAY 20 2013

MAIN FEATURE DURING THIS PERIOD WILL BE THE LARGE UPPER LOW OVER THE
PLAINS THAT IS EXPECTED TO GRADUALLY OPEN UP AND MOVE INTO THE
MIDWEST BY THURSDAY...KEEPING THE SHORT TERM UNSETTLED.

DETAILS REVOLVING AROUND THE FRONTAL BOUNDARY OR ANY EFFECTIVE
OUTFLOW BOUNDARIES TO FOCUS CONVECTION ON OVER THE NEXT COUPLE OF
DAYS IS STILL MURKY...WITH SEVERAL ROUNDS OF CONVECTION EXPECTED.
ACTUAL COLD FRONT MAY NOT PASS UNTIL WEDNESDAY NIGHT OR THURSDAY
MORNING. APPEARS FROM THE MODEL DATA...THE BEST PRECIPITATION
SIGNALS ARRIVE TUESDAY NIGHT AND WEDNESDAY...SO WILL GO WITH THE
HIGHEST POPS DURING THOSE TIMES. WILL GO WITH CHANCE POPS IN THE
OTHER PERIODS FOR NOW.

AT THIS POINT...THE COMBINATION OF LAPSE RATES AND DEEP LAYER SHEAR
SUGGEST THAT TUESDAY MAY HAVE THE BEST POTENTIAL FOR SEVERE
CONVECTION OVER THE NEXT COUPLE OF DAYS. BY WEDNESDAY...LAPSE RATES
BECOME POORER...WHICH SHOULD HELP TO DIMINISH THE SEVERE THREAT BY
THAT TIME.

GIVEN PROGGED LOW LEVEL THICKNESSES AND EXPECTED CONVECTION OR CLOUD
COVER...THE GFS MOS HIGHS FOR TUESDAY AND WEDNESDAY LOOK A LITTLE
WARM. WILL NUDGE THE NUMBERS DOWN A FEW DEGREES. GUIDANCE LOWS LOOK
OK.

&&

.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 210600Z TAF ISSUANCE/...

ISSUED AT 1215 AM EDT TUE MAY 21 2013

RADAR REFLECTIVITY AND RAPID REFRESH REFLECTIVITY PROGS SUGGESTS
LINE OF THUNDERSTORMS...ACROSS ILLINOIS WILL MOVE INTO THE LAF AND
HUF AREAS AROUND 07Z AND IND AND BMG AFTER 08Z. SO...WILL HAVE TEMPO
IFR THUNDERSTORMS THROUGH 11Z AT LAF AND HUF AND 12Z AT IND AND BMG
WITH VCTS FOR A FEW HOURS AFTER AS A BUFFER. THEN...ATMOSPHERE
LIKELY TO DESTABILIZE LATE IN THE DAY WITH MORE THUNDERSTORM
DEVELOPMENT ON TAP ESPECIALLY AFTER 00Z WEDNESDAY. COULD SEE WIND
GUSTS TO 40 KNOTS WITH SUSTAINED WINDS 20 KNOTS FROM THE SOUTHWEST
WITHIN THE LINE OVERNIGHT.

OTHERWISE...POTENTIAL FOR SOUTH AND SOUTHWEST WINDS TO NEAR 20 KNOTS
GUSTING TO NEAR 30 KNOTS AFTER 15Z TODAY AS THE ATMOSPHERE MIXES.


&&

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

$$

SYNOPSIS...JAS
NEAR TERM...JAS/50
SHORT TERM...JAS
LONG TERM....SMF
AVIATION...MK

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

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

000
FXUS63 KIWX 210629
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
229 AM EDT TUE MAY 21 2013

.AVIATION...(FOR THE 06Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED
AT 225 AM EDT TUE MAY 21 2013

MADE SOME ADJUSTMENTS TO TAFS TO ACCOMMODATE ACCELERATING LINE OF
STORMS MOVING OUT OF NE IL INTO NW INDIANA. SPC MESO ANALYSIS
SHOWS 3 HOUR SFC BASED CAPES CHANGES 200 TO 800 J/KG LOWER...SO
EXPECT STORMS TO GRADUALLY WEAKEN THE REST OF THE NIGHT. ALSO...
SOME SUPPORT FROM THE RIGHT ENTRANCE REGION OF AN UPPER LEVEL JET
WILL WANE AS THE JET AXIS TRANSLATES BACK TO THE WEST GIVEN THE
RESPONSE TO AN UPSTREAM TROF MOVING INTO THE CENTRAL PLAINS. SO
KEPT THUNDER OUT AFTER 12Z. A FAIRLY TIGHT PRESSURE GRADIENT WILL
PERSIST TODAY...WITH DAYTIME MIXING OF HIGHER MOMENTUM AIR CAUSING
SOUTHWEST GUSTS TO AROUND 25 KNOTS.

&&

.SYNOPSIS...
ISSUED AT 532 PM EDT MON MAY 20 2013

SHOWER AND THUNDERSTORM CHANCES WILL CONTINUE TO INCREASE TONIGHT
THROUGH WEDNESDAY...WITH A FEW SHOWERS POSSIBLY LINGERING INTO
THURSDAY. THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS THIS
EVENING THROUGH TUESDAY NIGHT. DRIER AND COOLER WEATHER IS
ANTICIPATED LATE THIS WEEK INTO NEXT WEEKEND.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 305 PM EDT MON MAY 20 2013

REMNANT GRAVITY WAVE FROM OVERNIGHT CONVECTION AND
ASSOCIATED WITH A ~10F DEGREE DEWPOINT DROP IN ITS WAKE HAS WASHED
OUT AS IT MOVED INTO OUR FORECAST AREA. THIS HAS KEPT MODERATELY
UNSTABLE AIRMASS ACROSS THE EASTERN TWO-THIRDS OF OUR FORECAST AREA.
ADDED SLIGHT CHANCE POPS FOR THE EAST THIS EVENING AS CONVECTION
COULD FIRE ALONG OR IN FRONT OF THIS BOUNDARY WHERE THE AIRMASS IS
CHARACTERIZED BY SBCAPE VALUES IN EXCESS OF 3000 J/KG. THE GREATEST
LIMITING FACTOR IS THE LACK OF SIGNIFICANT FORCING...ALTHOUGH
CONVECTION ACROSS MICHIGAN AND ADDITIONAL CONVECTION FIRING ALONG
THE BOUNDARY ACROSS EASTERN ILLINOIS AT 1830Z INDICATES THIS
BOUNDARY MAY PROVIDE JUST ENOUGH FORCED ASCENT FOR ISOLATED STORM
DEVELOPMENT.

STILL SOME UNCERTAINTY REGARDING CONVECTIVE EVOLUTION AND IMPACTS
ACROSS OUR AREA TONIGHT. DECAYING STORM CLUSTER ACROSS WESTERN
ILLINOIS SHOULD CONTINUE ITS WEAKENING TREND AS IT MOVES INTO A
MOISTURE VOID AREA ACROSS ILLINOIS WITH SURFACE DEWPOINTS IN THE
UPPER 50S. WITH THAT BEING SAID...SOME SHORT TERM MODEL GUIDANCE IS
INDICATING A QUICK RECOVERY OF THE MOISTURE PROFILE IN THAT AREA AS
850 MOISTURE TRANSPORT INCREASES THIS AFTERNOON. IF THE AIRMASS
AHEAD OF THESE STORMS CAN DESTABILIZE OVER THE NEXT FEW HOURS...AS
THE HRRR SUGGESTS...UPSCALE GROWTH OF THAT CLUSTER AS WELL AS
ADDITIONAL STORM DEVELOPMENT MAY TRACK ACROSS THE NORTHWEST PORTION
OF OUR FORECAST AREA DURING THE LATE EVENING. IF STORMS CAN
DEVELOP...SEVERE POTENTIAL DOES EXIST AS 0-6 KM SHEAR OF 35-45 KNOTS
OVERSPREADS THE NORTHWEST PORTION OF OUR FORECAST AREA WITH THE MAIN
THREATS BEING SEVERE HAIL AND WIND.

REMAIN MORE CONFIDENT IN PRECIPITATION CHANCES AFTER 06Z WHEN
REMNANT CONVECTION FROM MISSOURI TRACKS TOWARDS THE AREA. SEVERE
THREAT WILL BE MINIMAL WITH THIS CONVECTION DUE TO ITS TIMING DURING
THE EARLY MORNING HOURS.

TUESDAY LOOKS TO BE COOLER THAN TODAY AS LITTLE SUN WILL BE SEEN
ACROSS OUR FORECAST AREA DUE TO CLOUD DEBRIS FROM FROM OVERNIGHT
CONVECTION AS WELL AS ADDITIONAL DYNAMIC LIFT FROM 40-50 KT LLJ.
SEVERE THREAT DOES EXIST IF A FEW BREAKS IN THE CLOUDS CAN PROVIDE
SIGNIFICANT SURFACE HEATING FOR EVEN MARGINAL SURFACE BASED
INSTABILITY. THE MAIN THREAT WILL BE LARGE HAIL AND DAMAGING WINDS
AS UNIDIRECTIONAL 35-40 KNOT SHEAR OVERSPREADS THE AREA.

&&

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 305 PM EDT MON MAY 20 2013

ONE OR TWO MORE ROUNDS OF CONVECTION TO BEGIN THE FORECAST PERIOD.
MODELS IN PRETTY GOOD AGREEMENT IN SHORT WAVE COMING OUT OF BASE OF
CLOSED LOW AND IMPACTING THE AREA TUE NIGHT. GOOD SUPPORT WILL
ACCOMPANY THIS FEATURE AND 50-60KT MID LEVEL SPEED MAX WILL COMBINE
WITH INFLUX OF LOW LEVEL MOISTURE WITH AT LEAST SUFFICIENT
INSTABILITY TO INITIATE OR MAINTAIN CONVECTION. UNIDIRECTIONAL WIND
PROFILE WITH AROUND 30KT OF SPEED SHEAR WILL HAVE DAMAGING WINDS AS
THE MAIN SEVERE THREAT. CLOSED LOW FINALLY OPENS UP AND WILL MOVE
EASTWARD INTO THE GREAT LAKES REGION WEDNESDAY NIGHT...BRINGING SFC
LOW AND MAIN COLD FRONT WITH IT. MODELS OFFERING VARYING
TIMING/PLACEMENT OF THESE FEATURES BUT ONE MORE ROUND OF CONVECTION
POSSIBLE WEDNESDAY...MAINLY FOR THE EASTERN HALF OF THE CWA. UPPER
TROF AXIS ROTATES THROUGH THE AREA WEDNESDAY NIGHT INTO THURSDAY
KEEPING CHANCE FOR A FEW SHOWERS BEFORE COOLER DRIER CANADIAN HIGH
PRESSURE BEGINS TO BUILD INTO THE GREAT LAKES REGION ON FRIDAY. THIS
WILL PROVIDE A NICE START TO THE HOLIDAY WEEKEND...QUESTIONS REMAIN
AS TO WHETHER IT WILL LAST THROUGH MONDAY. SFC RIDGE AXIS WILL
PROGRESS EASTWARD SUNDAY AND MONDAY...PLACING OUR AREA ON THE
WESTERN PERIPHERY OF THE HIGH WHILE MEDIUM RANGE MODELS ATTEMPTING
TO BRING SHORT WAVE ENERGY DOWN IN NW FLOW. GETTING BETTER MODEL
AGREEMENT WITH THIS SOLN BUT LOTS OF VARIATION IN TIMING AND
PLACEMENT. ENSEMBLE GUIDANCE NEAR OR MOSTLY BELOW CLIMO FOR POPS AS
WELL SO WILL STILL HOLD OUT FOR DRY FORECAST FOR AT LEAST ONE MORE
ISSUANCE. TEMPS TRENDING SEASONABLY COOLER WITH AOB NORMAL FOR MOST

&&

.UPDATE...
ISSUED AT 857 PM EDT MON MAY 20 2013

DIFFICULT FORECAST WITH RESPECT TO CONVECTIVE PROBABILITIES THROUGH
THE FORECAST PERIOD AND DISMAL EARLY FAILURE. AMID A STRONGLY
DIVERGENT BOUNDARY LAYER AXIS PER VIS SAT IMAGERY LYING ACROSS
NERN IL/NWRN IN PAST FEW HOURS...HAS PROVEN TO BE STRONGLY
DETRIMENTAL. THIS DESPITE MODERATE SURFACE BASED INSTABILITY POOL
SITUATED ACROSS NORTHERN INDIANA/SOUTHERN LOWER MICHIGAN THIS
EVENING. A WELL SCOURED/DEEPLY MIXED ENVIRONMENT EXISTS ACROSS
NORTHERN/CENTRAL ILLINOIS WITH PUTRID MID/UPR 50S DPS THIS
EVENING...REMOVES ANY IMMEDIATE CONCERN FOR INITIATION NEXT FEW
HOURS. THIS IMMEDIATE UPSTREAM ENVIRON WAS WITHIN WAKE OF EARLY
AFTERNOON SHORTWAVE...THAT INITIATED STRONG/SEVERE CONVECTION
MIDDAY ACROSS YOOP/NORTHERN LOWER MICHIGAN. EASTERN FRINGE OF DRY
SLOTTED ENVIRONMENT WITH 7.5-8.25 C/KM MID LEVEL LAPSE RATES TO
LIKELY KEEP UPDRAFTS IN CHECK/ISOLATED REMAINDER OF THE EVENING.
WILL MAINTAIN THAT ANY SIG CHANCE FOR CONVECTION TO BE ASSOCIATED
WITH WELL UPSTREAM CONVECTION PRESENTLY ACROSS EAST CENTRAL
MO...WITH SEVERAL HOUR WAIT UNTIL A MORE VIGORED UPSTREAM 925-8H
WIND FIELD WITH PRESENT FOCUS INTO THE OZARKS/NORTHERN ARKANSAS
SHIFTS NORTHEASTWARD OVERNIGHT INTO SRN/CENTRAL ILLINOIS WHILE
JETLET VEERS/RAMPS TO 45-55KTS...FINALLY NOSING INTO KLAF VCNTY
AROUND 09-12 UTC PER RAP/ARW...AND A SIGNIFICANTLY POOR/LAGGARD
HRRR3KM THAT RECENTLY CAME IN LINE TO REALITY. SUFFICIENT
PREPARATORY CONDITIONING/RECOVERY OF ENVIRONMENT VIA MOISTURE
FLUX CONVERGENCE SFC-900MB ALONG/NORTH OF STRONG ISODROSOTHERMAL
GRADIENT WITH UPPER 60S/NEAR 70 DPS SOURCE TAPPED WITH
TIME....PUSHING NORTH OF I70 TO MAINTAIN MUCAPE POOL OF 1200-2000
J/KG ACROSS FORECAST AREA. THIS SHOULD ALLOW DECENT MAINTENANCE OF
CONVECTIVE COMPLEX WITH ACROSS MISSOURI TO REACH NORTHERN INDIANA
WELL AFTER MIDNIGHT INTO KSBN AND NEAR DAYBREAK AT KFWA.
DISFAVORED TIMING/PARCEL ASCENT BECOMING LESS SURFACE BASED WITH
TIME AND MODEST DEEP LAYER SHEAR TO LARGELY PRECLUDE SEVERE
POTENTIAL...THOUGH HAVE CONTD TO ACK THAT STRONGEST CELLS MAY
APPROACH LOW END SEVERE LIMITS IN HWO.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...STEINWEDEL/KG
AVIATION...SKIPPER
SHORT TERM...BENTLEY
LONG TERM...JAL
UPDATE...MURPHY


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIND 210416
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1215 AM EDT TUE MAY 21 2013

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

&&

.SYNOPSIS...
ISSUED AT 239 PM EDT MON MAY 20 2013

A LARGE UPPER LOW CURRENTLY OVER THE PLAINS IS EXPECTED TO BRING
UNSETTLED WEATHER TO THE AREA THROUGH THURSDAY AS IT SLOWLY MOVES
EAST AND WEAKENS WITH TIME. IN THE WAKE OF THIS SYSTEM...HIGH
PRESSURE IS EXPECTED TO BUILD INTO THE AREA OVER THE WEEKEND AND
INTO EARLY NEXT WEEK.

&&

.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 835 PM EDT MON MAY 20 2013

CONVECTION ACROSS THE FORECAST AREA HAS CEASED...AND NOW FOCUS IS ON
CONVECTION MOVING INTO ILLINOIS AT THE MOMENT.

CURRENT TIMING ON CONVECTION IN ILLINOIS PUTS IT IN CENTRAL INDIANA
AFTER MIDNIGHT. THUS HAVE REMOVED POPS MOST AREAS UNTIL AFTER
MIDNIGHT...THEN GRADUALLY INCREASED THEM BACK UP TO PREVIOUS
FORECAST. MAY HAVE TO UP THEM INTO LIKELY OR HIGHER CATEGORY LATER
THIS EVENING DEPENDING ON HOW CONVECTION IN ILLINOIS MOVES/DEVELOPS.
RIGHT NOW THE NORTHWEST FORECAST AREA LOOKS TO BE THE AREA WHERE
POPS WOULD HAVE TO BE INCREASED.

DEEP LAYER SHEAR...INITIALLY RATHER WEAK THIS EVENING...IS EXPECTED
TO STRENGTHEN LATER TONIGHT. AS A RESULT...THINK THE POTENTIAL FOR
ORGANIZED SEVERE CONVECTION SHOULD GRADUALLY INCREASE AS TIME GOES
BY TONIGHT. THUS WILL CONTINUE TO MENTION SEVERE THREAT FOR AFTER
MIDNIGHT.

NO CHANGES MADE TO TEMPERATURES AT THIS TIME.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
ISSUED AT 239 PM EDT MON MAY 20 2013

MAIN FEATURE DURING THIS PERIOD WILL BE THE LARGE UPPER LOW OVER THE
PLAINS THAT IS EXPECTED TO GRADUALLY OPEN UP AND MOVE INTO THE
MIDWEST BY THURSDAY...KEEPING THE SHORT TERM UNSETTLED.

DETAILS REVOLVING AROUND THE FRONTAL BOUNDARY OR ANY EFFECTIVE
OUTFLOW BOUNDARIES TO FOCUS CONVECTION ON OVER THE NEXT COUPLE OF
DAYS IS STILL MURKY...WITH SEVERAL ROUNDS OF CONVECTION EXPECTED.
ACTUAL COLD FRONT MAY NOT PASS UNTIL WEDNESDAY NIGHT OR THURSDAY
MORNING. APPEARS FROM THE MODEL DATA...THE BEST PRECIPITATION
SIGNALS ARRIVE TUESDAY NIGHT AND WEDNESDAY...SO WILL GO WITH THE
HIGHEST POPS DURING THOSE TIMES. WILL GO WITH CHANCE POPS IN THE
OTHER PERIODS FOR NOW.

AT THIS POINT...THE COMBINATION OF LAPSE RATES AND DEEP LAYER SHEAR
SUGGEST THAT TUESDAY MAY HAVE THE BEST POTENTIAL FOR SEVERE
CONVECTION OVER THE NEXT COUPLE OF DAYS. BY WEDNESDAY...LAPSE RATES
BECOME POORER...WHICH SHOULD HELP TO DIMINISH THE SEVERE THREAT BY
THAT TIME.

GIVEN PROGGED LOW LEVEL THICKNESSES AND EXPECTED CONVECTION OR CLOUD
COVER...THE GFS MOS HIGHS FOR TUESDAY AND WEDNESDAY LOOK A LITTLE
WARM. WILL NUDGE THE NUMBERS DOWN A FEW DEGREES. GUIDANCE LOWS LOOK
OK.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ISSUED AT 239 PM EDT MON MAY 20 2013

DRY WEATHER IS ANTICIPATED DURING THIS PERIOD AND THE ECMWF AND
THE GFS BOTH AGREE IN BUILDING A LARGE RIDGE OVER THE CENTRAL
PLAINS ACROSS INDIANA DURING THIS TIME. A SHORT WAVE TROUGH WILL
EXIT THE AREA ON THURSDAY...ALLOWING THE LEE SIDE OF THE RIDGE AND
ASSOCIATED SUBSIDENCE ON NORTHWEST WIND TO ARRIVE ACROSS THE AREA
FOR FRIDAY AND SATURDAY. THIS WILL RESULT IN DRY WEATHER WITH
TEMPS AT OR BELOW SEASONABLE NORMALS AS DUE TO THE COOL CANADIAN
AIR.

TEMPS WILL GRADUALLY WARM ON SUNDAY AND MONDAY AS THE RIDGE
PROGRESSES EASTWARD AND WARMER...MORE HUMID AIR ARRIVES ON
SOUTHERLY WINDS ON THE BACK OF THE RIDGE.

&&

.AVIATION /DISCUSSION FOR THE 210600Z TAF ISSUANCE/...

ISSUED AT 1215 AM EDT TUE MAY 21 2013

RADAR REFLECTIVITY AND RAPID REFRESH REFLECTIVITY PROGS SUGGESTS
LINE OF THUNDERSTORMS...ACROSS ILLINOIS WILL MOVE INTO THE LAF AND
HUF AREAS AROUND 07Z AND IND AND BMG AFTER 08Z. SO...WILL HAVE TEMPO
IFR THUNDERSTORMS THROUGH 11Z AT LAF AND HUF AND 12Z AT IND AND BMG
WITH VCTS FOR A FEW HOURS AFTER AS A BUFFER. THEN...ATMOSPHERE
LIKELY TO DESTABILIZE LATE IN THE DAY WITH MORE THUNDERSTORM
DEVELOPMENT ON TAP ESPECIALLY AFTER 00Z WEDNESDAY. COULD SEE WIND
GUSTS TO 40 KNOTS WITH SUSTAINED WINDS 20 KNOTS FROM THE SOUTHWEST
WITHIN THE LINE OVERNIGHT.

OTHERWISE...POTENTIAL FOR SOUTH AND SOUTHWEST WINDS TO NEAR 20 KNOTS
GUSTING TO NEAR 30 KNOTS AFTER 15Z TODAY AS THE ATMOSPHERE MIXES.

&&

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

$$

SYNOPSIS...JAS
NEAR TERM...JAS/50
SHORT TERM...JAS
LONG TERM....PUMA
AVIATION...MK

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

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

000
FXUS63 KIND 210227
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1025 PM EDT MON MAY 20 2013

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

&&

.SYNOPSIS...
ISSUED AT 239 PM EDT MON MAY 20 2013

A LARGE UPPER LOW CURRENTLY OVER THE PLAINS IS EXPECTED TO BRING
UNSETTLED WEATHER TO THE AREA THROUGH THURSDAY AS IT SLOWLY MOVES
EAST AND WEAKENS WITH TIME. IN THE WAKE OF THIS SYSTEM...HIGH
PRESSURE IS EXPECTED TO BUILD INTO THE AREA OVER THE WEEKEND AND
INTO EARLY NEXT WEEK.

&&

.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 835 PM EDT MON MAY 20 2013

CONVECTION ACROSS THE FORECAST AREA HAS CEASED...AND NOW FOCUS IS ON
CONVECTION MOVING INTO ILLINOIS AT THE MOMENT.

CURRENT TIMING ON CONVECTION IN ILLINOIS PUTS IT IN CENTRAL INDIANA
AFTER MIDNIGHT. THUS HAVE REMOVED POPS MOST AREAS UNTIL AFTER
MIDNIGHT...THEN GRADUALLY INCREASED THEM BACK UP TO PREVIOUS
FORECAST. MAY HAVE TO UP THEM INTO LIKELY OR HIGHER CATEGORY LATER
THIS EVENING DEPENDING ON HOW CONVECTION IN ILLINOIS MOVES/DEVELOPS.
RIGHT NOW THE NORTHWEST FORECAST AREA LOOKS TO BE THE AREA WHERE
POPS WOULD HAVE TO BE INCREASED.

DEEP LAYER SHEAR...INITIALLY RATHER WEAK THIS EVENING...IS EXPECTED
TO STRENGTHEN LATER TONIGHT. AS A RESULT...THINK THE POTENTIAL FOR
ORGANIZED SEVERE CONVECTION SHOULD GRADUALLY INCREASE AS TIME GOES
BY TONIGHT. THUS WILL CONTINUE TO MENTION SEVERE THREAT FOR AFTER
MIDNIGHT.

NO CHANGES MADE TO TEMPERATURES AT THIS TIME.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
ISSUED AT 239 PM EDT MON MAY 20 2013

MAIN FEATURE DURING THIS PERIOD WILL BE THE LARGE UPPER LOW OVER THE
PLAINS THAT IS EXPECTED TO GRADUALLY OPEN UP AND MOVE INTO THE
MIDWEST BY THURSDAY...KEEPING THE SHORT TERM UNSETTLED.

DETAILS REVOLVING AROUND THE FRONTAL BOUNDARY OR ANY EFFECTIVE
OUTFLOW BOUNDARIES TO FOCUS CONVECTION ON OVER THE NEXT COUPLE OF
DAYS IS STILL MURKY...WITH SEVERAL ROUNDS OF CONVECTION EXPECTED.
ACTUAL COLD FRONT MAY NOT PASS UNTIL WEDNESDAY NIGHT OR THURSDAY
MORNING. APPEARS FROM THE MODEL DATA...THE BEST PRECIPITATION
SIGNALS ARRIVE TUESDAY NIGHT AND WEDNESDAY...SO WILL GO WITH THE
HIGHEST POPS DURING THOSE TIMES. WILL GO WITH CHANCE POPS IN THE
OTHER PERIODS FOR NOW.

AT THIS POINT...THE COMBINATION OF LAPSE RATES AND DEEP LAYER SHEAR
SUGGEST THAT TUESDAY MAY HAVE THE BEST POTENTIAL FOR SEVERE
CONVECTION OVER THE NEXT COUPLE OF DAYS. BY WEDNESDAY...LAPSE RATES
BECOME POORER...WHICH SHOULD HELP TO DIMINISH THE SEVERE THREAT BY
THAT TIME.

GIVEN PROGGED LOW LEVEL THICKNESSES AND EXPECTED CONVECTION OR CLOUD
COVER...THE GFS MOS HIGHS FOR TUESDAY AND WEDNESDAY LOOK A LITTLE
WARM. WILL NUDGE THE NUMBERS DOWN A FEW DEGREES. GUIDANCE LOWS LOOK
OK.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ISSUED AT 239 PM EDT MON MAY 20 2013

DRY WEATHER IS ANTICIPATED DURING THIS PERIOD AND THE ECMWF AND
THE GFS BOTH AGREE IN BUILDING A LARGE RIDGE OVER THE CENTRAL
PLAINS ACROSS INDIANA DURING THIS TIME. A SHORT WAVE TROUGH WILL
EXIT THE AREA ON THURSDAY...ALLOWING THE LEE SIDE OF THE RIDGE AND
ASSOCIATED SUBSIDENCE ON NORTHWEST WIND TO ARRIVE ACROSS THE AREA
FOR FRIDAY AND SATURDAY. THIS WILL RESULT IN DRY WEATHER WITH
TEMPS AT OR BELOW SEASONABLE NORMALS AS DUE TO THE COOL CANADIAN
AIR.

TEMPS WILL GRADUALLY WARM ON SUNDAY AND MONDAY AS THE RIDGE
PROGRESSES EASTWARD AND WARMER...MORE HUMID AIR ARRIVES ON
SOUTHERLY WINDS ON THE BACK OF THE RIDGE.

&&

.AVIATION /DISCUSSION FOR THE 210300Z IND TAF UPDATE/...

ISSUED AT 1025 PM EDT MON MAY 20 2013

ADDED TEMPO THUNDERSTORMS 08Z-12Z BASED ON RADAR TRENDS ALONG WITH
LATEST RAPID REFRESH REFLECTIVITY PROGS.

PREVIOUS DISCUSSION FOLLOWS...

CONDITIONS SHOULD BE VFR THROUGH THE TAF PERIOD EXCEPT PERHAPS IN
THUNDERSTORMS. LOOKS LIKE THIS EVENING WILL BE QUIET WITH
THUNDERSTORM CHANCES INCREASING AFTER 06Z ESPECIALLY AT HUF AND LAF.
ACTIVITY EXPECTED TO COME FROM CURRENT MISSOURI STORMS. FOR
NOW...WILL GO WITH VCTS AND CONSIDER TEMPO GROUPS LATER IF ACTIVITY
CAN BE CONFIDENTLY TIMED ACROSS ONE OR MORE OF THE TERMINALS. SOUTH
WINDS SHOULD STAY UP AROUND 10 KNOTS TONIGHT PERHAPS GUSTING TO NEAR
20 AT TIMES. AFTER 15Z TUESDAY...SHOULD SEE SOME BREAKS IN THE
CLOUDS WHICH SHOULD ALLOW GOOD MIXING AND SOUTHWEST WINDS NEAR 20
KNOTS AND GUSTING TO NEAR 30 KNOTS. COULD ALSO SEE SOME MORE
THUNDERSTORM ACTIVITY...BUT BETTER CHANCE AFTER 00Z WEDNESDAY...SO
WILL ONLY GO WITH VCTS FOR NOW AFTER 19Z EXCEPT PROB30 AT IND AFTER
00Z WEDNESDAY.

&&

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

$$

SYNOPSIS...JAS
NEAR TERM...JAS/50
SHORT TERM...JAS
LONG TERM....PUMA
AVIATION...MK

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

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

000
FXUS63 KIWX 210100
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
900 PM EDT MON MAY 20 2013

.AVIATION/UPDATE...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 857 PM EDT MON MAY 20 2013

DIFFICULT FORECAST WITH RESPECT TO CONVECTIVE PROBABILITIES THROUGH
THE FORECAST PERIOD AND DISMAL EARLY FAILURE. AMID A STRONGLY
DIVERGENT BOUNDARY LAYER AXIS PER VIS SAT IMAGERY LYING ACROSS
NERN IL/NWRN IN PAST FEW HOURS...HAS PROVEN TO BE STRONGLY
DETRIMENTAL. THIS DESPITE MODERATE SURFACE BASED INSTABILITY POOL
SITUATED ACROSS NORTHERN INDIANA/SOUTHERN LOWER MICHIGAN THIS
EVENING. A WELL SCOURED/DEEPLY MIXED ENVIRONMENT EXISTS ACROSS
NORTHERN/CENTRAL ILLINOIS WITH PUTRID MID/UPR 50S DPS THIS
EVENING...REMOVES ANY IMMEDIATE CONCERN FOR INITIATION NEXT FEW
HOURS. THIS IMMEDIATE UPSTREAM ENVIRON WAS WITHIN WAKE OF EARLY
AFTERNOON SHORTWAVE...THAT INITIATED STRONG/SEVERE CONVECTION
MIDDAY ACROSS YOOP/NORTHERN LOWER MICHIGAN. EASTERN FRINGE OF DRY
SLOTTED ENVIRONMENT WITH 7.5-8.25 C/KM MID LEVEL LAPSE RATES TO
LIKELY KEEP UPDRAFTS IN CHECK/ISOLATED REMAINDER OF THE EVENING.
WILL MAINTAIN THAT ANY SIG CHANCE FOR CONVECTION TO BE ASSOCIATED
WITH WELL UPSTREAM CONVECTION PRESENTLY ACROSS EAST CENTRAL
MO...WITH SEVERAL HOUR WAIT UNTIL A MORE VIGORED UPSTREAM 925-8H
WIND FIELD WITH PRESENT FOCUS INTO THE OZARKS/NORTHERN ARKANSAS
SHIFTS NORTHEASTWARD OVERNIGHT INTO SRN/CENTRAL ILLINOIS WHILE
JETLET VEERS/RAMPS TO 45-55KTS...FINALLY NOSING INTO KLAF VCNTY
AROUND 09-12 UTC PER RAP/ARW...AND A SIGNIFICANTLY POOR/LAGGARD
HRRR3KM THAT RECENTLY CAME IN LINE TO REALITY. SUFFICIENT
PREPARATORY CONDITIONING/RECOVERY OF ENVIRONMENT VIA MOISTURE
FLUX CONVERGENCE SFC-900MB ALONG/NORTH OF STRONG ISODROSOTHERMAL
GRADIENT WITH UPPER 60S/NEAR 70 DPS SOURCE TAPPED WITH
TIME....PUSHING NORTH OF I70 TO MAINTAIN MUCAPE POOL OF 1200-2000
J/KG ACROSS FORECAST AREA. THIS SHOULD ALLOW DECENT MAINTENANCE OF
CONVECTIVE COMPLEX WITH ACROSS MISSOURI TO REACH NORTHERN INDIANA
WELL AFTER MIDNIGHT INTO KSBN AND NEAR DAYBREAK AT KFWA.
DISFAVORED TIMING/PARCEL ASCENT BECOMING LESS SURFACE BASED WITH
TIME AND MODEST DEEP LAYER SHEAR TO LARGELY PRECLUDE SEVERE
POTENTIAL...THOUGH HAVE CONTD TO ACK THAT STRONGEST CELLS MAY
APPROACH LOW END SEVERE LIMITS IN HWO.

&&

.SYNOPSIS...
ISSUED AT 532 PM EDT MON MAY 20 2013

SHOWER AND THUNDERSTORM CHANCES WILL CONTINUE TO INCREASE TONIGHT
THROUGH WEDNESDAY...WITH A FEW SHOWERS POSSIBLY LINGERING INTO
THURSDAY. THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS THIS
EVENING THROUGH TUESDAY NIGHT. DRIER AND COOLER WEATHER IS
ANTICIPATED LATE THIS WEEK INTO NEXT WEEKEND.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 305 PM EDT MON MAY 20 2013

REMNANT GRAVITY WAVE FROM OVERNIGHT CONVECTION AND
ASSOCIATED WITH A ~10F DEGREE DEWPOINT DROP IN ITS WAKE HAS WASHED
OUT AS IT MOVED INTO OUR FORECAST AREA. THIS HAS KEPT MODERATELY
UNSTABLE AIRMASS ACROSS THE EASTERN TWO-THIRDS OF OUR FORECAST AREA.
ADDED SLIGHT CHANCE POPS FOR THE EAST THIS EVENING AS CONVECTION
COULD FIRE ALONG OR IN FRONT OF THIS BOUNDARY WHERE THE AIRMASS IS
CHARACTERIZED BY SBCAPE VALUES IN EXCESS OF 3000 J/KG. THE GREATEST
LIMITING FACTOR IS THE LACK OF SIGNIFICANT FORCING...ALTHOUGH
CONVECTION ACROSS MICHIGAN AND ADDITIONAL CONVECTION FIRING ALONG
THE BOUNDARY ACROSS EASTERN ILLINOIS AT 1830Z INDICATES THIS
BOUNDARY MAY PROVIDE JUST ENOUGH FORCED ASCENT FOR ISOLATED STORM
DEVELOPMENT.

STILL SOME UNCERTAINTY REGARDING CONVECTIVE EVOLUTION AND IMPACTS
ACROSS OUR AREA TONIGHT. DECAYING STORM CLUSTER ACROSS WESTERN
ILLINOIS SHOULD CONTINUE ITS WEAKENING TREND AS IT MOVES INTO A
MOISTURE VOID AREA ACROSS ILLINOIS WITH SURFACE DEWPOINTS IN THE
UPPER 50S. WITH THAT BEING SAID...SOME SHORT TERM MODEL GUIDANCE IS
INDICATING A QUICK RECOVERY OF THE MOISTURE PROFILE IN THAT AREA AS
850 MOISTURE TRANSPORT INCREASES THIS AFTERNOON. IF THE AIRMASS
AHEAD OF THESE STORMS CAN DESTABILIZE OVER THE NEXT FEW HOURS...AS
THE HRRR SUGGESTS...UPSCALE GROWTH OF THAT CLUSTER AS WELL AS
ADDITIONAL STORM DEVELOPMENT MAY TRACK ACROSS THE NORTHWEST PORTION
OF OUR FORECAST AREA DURING THE LATE EVENING. IF STORMS CAN
DEVELOP...SEVERE POTENTIAL DOES EXIST AS 0-6 KM SHEAR OF 35-45 KNOTS
OVERSPREADS THE NORTHWEST PORTION OF OUR FORECAST AREA WITH THE MAIN
THREATS BEING SEVERE HAIL AND WIND.

REMAIN MORE CONFIDENT IN PRECIPITATION CHANCES AFTER 06Z WHEN
REMNANT CONVECTION FROM MISSOURI TRACKS TOWARDS THE AREA. SEVERE
THREAT WILL BE MINIMAL WITH THIS CONVECTION DUE TO ITS TIMING DURING
THE EARLY MORNING HOURS.

TUESDAY LOOKS TO BE COOLER THAN TODAY AS LITTLE SUN WILL BE SEEN
ACROSS OUR FORECAST AREA DUE TO CLOUD DEBRIS FROM FROM OVERNIGHT
CONVECTION AS WELL AS ADDITIONAL DYNAMIC LIFT FROM 40-50 KT LLJ.
SEVERE THREAT DOES EXIST IF A FEW BREAKS IN THE CLOUDS CAN PROVIDE
SIGNIFICANT SURFACE HEATING FOR EVEN MARGINAL SURFACE BASED
INSTABILITY. THE MAIN THREAT WILL BE LARGE HAIL AND DAMAGING WINDS
AS UNIDIRECTIONAL 35-40 KNOT SHEAR OVERSPREADS THE AREA.

&&

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 305 PM EDT MON MAY 20 2013

ONE OR TWO MORE ROUNDS OF CONVECTION TO BEGIN THE FORECAST PERIOD.
MODELS IN PRETTY GOOD AGREEMENT IN SHORT WAVE COMING OUT OF BASE OF
CLOSED LOW AND IMPACTING THE AREA TUE NIGHT. GOOD SUPPORT WILL
ACCOMPANY THIS FEATURE AND 50-60KT MID LEVEL SPEED MAX WILL COMBINE
WITH INFLUX OF LOW LEVEL MOISTURE WITH AT LEAST SUFFICIENT
INSTABILITY TO INITIATE OR MAINTAIN CONVECTION. UNIDIRECTIONAL WIND
PROFILE WITH AROUND 30KT OF SPEED SHEAR WILL HAVE DAMAGING WINDS AS
THE MAIN SEVERE THREAT. CLOSED LOW FINALLY OPENS UP AND WILL MOVE
EASTWARD INTO THE GREAT LAKES REGION WEDNESDAY NIGHT...BRINGING SFC
LOW AND MAIN COLD FRONT WITH IT. MODELS OFFERING VARYING
TIMING/PLACEMENT OF THESE FEATURES BUT ONE MORE ROUND OF CONVECTION
POSSIBLE WEDNESDAY...MAINLY FOR THE EASTERN HALF OF THE CWA. UPPER
TROF AXIS ROTATES THROUGH THE AREA WEDNESDAY NIGHT INTO THURSDAY
KEEPING CHANCE FOR A FEW SHOWERS BEFORE COOLER DRIER CANADIAN HIGH
PRESSURE BEGINS TO BUILD INTO THE GREAT LAKES REGION ON FRIDAY. THIS
WILL PROVIDE A NICE START TO THE HOLIDAY WEEKEND...QUESTIONS REMAIN
AS TO WHETHER IT WILL LAST THROUGH MONDAY. SFC RIDGE AXIS WILL
PROGRESS EASTWARD SUNDAY AND MONDAY...PLACING OUR AREA ON THE
WESTERN PERIPHERY OF THE HIGH WHILE MEDIUM RANGE MODELS ATTEMPTING
TO BRING SHORT WAVE ENERGY DOWN IN NW FLOW. GETTING BETTER MODEL
AGREEMENT WITH THIS SOLN BUT LOTS OF VARIATION IN TIMING AND
PLACEMENT. ENSEMBLE GUIDANCE NEAR OR MOSTLY BELOW CLIMO FOR POPS AS
WELL SO WILL STILL HOLD OUT FOR DRY FORECAST FOR AT LEAST ONE MORE
ISSUANCE. TEMPS TRENDING SEASONABLY COOLER WITH AOB NORMAL FOR MOST

&&


.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...STEINWEDEL/KG
SHORT TERM...BENTLEY
LONG TERM...JAL
AVIATION/UPDATE...MURPHY


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIND 210035
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
835 PM EDT MON MAY 20 2013

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

&&

.SYNOPSIS...
ISSUED AT 239 PM EDT MON MAY 20 2013

A LARGE UPPER LOW CURRENTLY OVER THE PLAINS IS EXPECTED TO BRING
UNSETTLED WEATHER TO THE AREA THROUGH THURSDAY AS IT SLOWLY MOVES
EAST AND WEAKENS WITH TIME. IN THE WAKE OF THIS SYSTEM...HIGH
PRESSURE IS EXPECTED TO BUILD INTO THE AREA OVER THE WEEKEND AND
INTO EARLY NEXT WEEK.

&&

.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 835 PM EDT MON MAY 20 2013

CONVECTION ACROSS THE FORECAST AREA HAS CEASED...AND NOW FOCUS IS ON
CONVECTION MOVING INTO ILLINOIS AT THE MOMENT.

CURRENT TIMING ON CONVECTION IN ILLINOIS PUTS IT IN CENTRAL INDIANA
AFTER MIDNIGHT. THUS HAVE REMOVED POPS MOST AREAS UNTIL AFTER
MIDNIGHT...THEN GRADUALLY INCREASED THEM BACK UP TO PREVIOUS
FORECAST. MAY HAVE TO UP THEM INTO LIKELY OR HIGHER CATEGORY LATER
THIS EVENING DEPENDING ON HOW CONVECTION IN ILLINOIS MOVES/DEVELOPS.
RIGHT NOW THE NORTHWEST FORECAST AREA LOOKS TO BE THE AREA WHERE
POPS WOULD HAVE TO BE INCREASED.

DEEP LAYER SHEAR...INITIALLY RATHER WEAK THIS EVENING...IS EXPECTED
TO STRENGTHEN LATER TONIGHT. AS A RESULT...THINK THE POTENTIAL FOR
ORGANIZED SEVERE CONVECTION SHOULD GRADUALLY INCREASE AS TIME GOES
BY TONIGHT. THUS WILL CONTINUE TO MENTION SEVERE THREAT FOR AFTER
MIDNIGHT.

NO CHANGES MADE TO TEMPERATURES AT THIS TIME.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
ISSUED AT 239 PM EDT MON MAY 20 2013

MAIN FEATURE DURING THIS PERIOD WILL BE THE LARGE UPPER LOW OVER THE
PLAINS THAT IS EXPECTED TO GRADUALLY OPEN UP AND MOVE INTO THE
MIDWEST BY THURSDAY...KEEPING THE SHORT TERM UNSETTLED.

DETAILS REVOLVING AROUND THE FRONTAL BOUNDARY OR ANY EFFECTIVE
OUTFLOW BOUNDARIES TO FOCUS CONVECTION ON OVER THE NEXT COUPLE OF
DAYS IS STILL MURKY...WITH SEVERAL ROUNDS OF CONVECTION EXPECTED.
ACTUAL COLD FRONT MAY NOT PASS UNTIL WEDNESDAY NIGHT OR THURSDAY
MORNING. APPEARS FROM THE MODEL DATA...THE BEST PRECIPITATION
SIGNALS ARRIVE TUESDAY NIGHT AND WEDNESDAY...SO WILL GO WITH THE
HIGHEST POPS DURING THOSE TIMES. WILL GO WITH CHANCE POPS IN THE
OTHER PERIODS FOR NOW.

AT THIS POINT...THE COMBINATION OF LAPSE RATES AND DEEP LAYER SHEAR
SUGGEST THAT TUESDAY MAY HAVE THE BEST POTENTIAL FOR SEVERE
CONVECTION OVER THE NEXT COUPLE OF DAYS. BY WEDNESDAY...LAPSE RATES
BECOME POORER...WHICH SHOULD HELP TO DIMINISH THE SEVERE THREAT BY
THAT TIME.

GIVEN PROGGED LOW LEVEL THICKNESSES AND EXPECTED CONVECTION OR CLOUD
COVER...THE GFS MOS HIGHS FOR TUESDAY AND WEDNESDAY LOOK A LITTLE
WARM. WILL NUDGE THE NUMBERS DOWN A FEW DEGREES. GUIDANCE LOWS LOOK
OK.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ISSUED AT 239 PM EDT MON MAY 20 2013

DRY WEATHER IS ANTICIPATED DURING THIS PERIOD AND THE ECMWF AND
THE GFS BOTH AGREE IN BUILDING A LARGE RIDGE OVER THE CENTRAL
PLAINS ACROSS INDIANA DURING THIS TIME. A SHORT WAVE TROUGH WILL
EXIT THE AREA ON THURSDAY...ALLOWING THE LEE SIDE OF THE RIDGE AND
ASSOCIATED SUBSIDENCE ON NORTHWEST WIND TO ARRIVE ACROSS THE AREA
FOR FRIDAY AND SATURDAY. THIS WILL RESULT IN DRY WEATHER WITH
TEMPS AT OR BELOW SEASONABLE NORMALS AS DUE TO THE COOL CANADIAN
AIR.

TEMPS WILL GRADUALLY WARM ON SUNDAY AND MONDAY AS THE RIDGE
PROGRESSES EASTWARD AND WARMER...MORE HUMID AIR ARRIVES ON
SOUTHERLY WINDS ON THE BACK OF THE RIDGE.

&&

.AVIATION /DISCUSSION FOR THE 210000Z TAF ISSUANCE/...

ISSUED AT 700 PM EDT MON MAY 20 2013

CONDITIONS SHOULD BE VFR THROUGH THE TAF PERIOD EXCEPT PERHAPS IN
THUNDERSTORMS. LOOKS LIKE THIS EVENING WILL BE QUIET WITH
THUNDERSTORM CHANCES INCREASING AFTER 06Z ESPECIALLY AT HUF AND LAF.
ACTIVITY EXPECTED TO COME FROM CURRENT MISSOURI STORMS. FOR
NOW...WILL GO WITH VCTS AND CONSIDER TEMPO GROUPS LATER IF ACTIVITY
CAN BE CONFIDENTLY TIMED ACROSS ONE OR MORE OF THE TERMINALS. SOUTH
WINDS SHOULD STAY UP AROUND 10 KNOTS TONIGHT PERHAPS GUSTING TO NEAR
20 AT TIMES. AFTER 15Z TUESDAY...SHOULD SEE SOME BREAKS IN THE
CLOUDS WHICH SHOULD ALLOW GOOD MIXING AND SOUTHWEST WINDS NEAR 20
KNOTS AND GUSTING TO NEAR 30 KNOTS. COULD ALSO SEE SOME MORE
THUNDERSTORM ACTIVITY...BUT BETTER CHANCE AFTER 00Z WEDNESDAY...SO
WILL ONLY GO WITH VCTS FOR NOW AFTER 19Z EXCEPT PROB30 AT IND AFTER
00Z WEDNESDAY.

&&

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

$$

SYNOPSIS...JAS
NEAR TERM...JAS/50
SHORT TERM...JAS
LONG TERM....PUMA
AVIATION...MK

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

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

000
FXUS63 KIND 202304
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
700 PM EDT MON MAY 20 2013

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

&&

.SYNOPSIS...
ISSUED AT 239 PM EDT MON MAY 20 2013

A LARGE UPPER LOW CURRENTLY OVER THE PLAINS IS EXPECTED TO BRING
UNSETTLED WEATHER TO THE AREA THROUGH THURSDAY AS IT SLOWLY MOVES
EAST AND WEAKENS WITH TIME. IN THE WAKE OF THIS SYSTEM...HIGH
PRESSURE IS EXPECTED TO BUILD INTO THE AREA OVER THE WEEKEND AND
INTO EARLY NEXT WEEK.

&&

.NEAR TERM /REST OF THIS AFTERNOON AND TONIGHT/...
ISSUED AT 239 PM EDT MON MAY 20 2013

DEWPOINT DISCONTINUITY LINGERS OVER THE NORTHWEST ZONES...WITH
DEWPOINTS MIXING OUT INTO THE 50S OVER NORTHERN ILLINOIS. THIS MAY
BE EITHER THE REMNANTS OF AN OUTFLOW OR A FRONTAL SYSTEM. IN ANY
EVENT...AIR MASS OVER THE LOCAL AREA CONTINUES TO BE CAPPED...BUT
VERY UNSTABLE. SHORT TERM MODEL DATA SUGGEST THIS CAP MAY WEAKEN
AROUND 202200Z OR SO...LEADING TO THE POTENTIAL FOR THUNDERSTORM
DEVELOPMENT NEAR THIS DISCONTINUITY BY EARLY EVENING.
HOWEVER...THERE IS A QUESTION WHETHER THIS CAP WILL ACTUALLY BREAK.
MODEL DATA ALSO BRING IN AN AREA OF ORGANIZED LIFT DURING THE PRE
DAWN HOURS OF TUESDAY...PROBABLY RELATED TO CONVECTION THAT IS
EXPECTED TO DEVELOP FARTHER WEST LATER THIS AFTERNOON/EVENING.
THIS MAY RESULT IN ANOTHER ENHANCED CHANCE FOR CONVECTION BY EARLY
MORNING TUESDAY. DUE TO QUESTIONS REVOLVING AROUND THE CAP AND ANY
FUTURE STORM DEVELOPMENT...WILL KEEP POPS IN THE CHANCE CATEGORY
TONIGHT...HIGHEST IN THE WEST/NORTHWEST.

LAPSE RATE REMAIN QUITE FAVORABLE FOR SEVERE CONVECTION TONIGHT.
DEEP LAYER SHEAR...INITIALLY RATHER WEAK THIS EVENING...IS EXPECTED
TO STRENGTHEN LATER TONIGHT. AS A RESULT...THINK THE POTENTIAL FOR
ORGANIZED SEVERE CONVECTION SHOULD GRADUALLY INCREASE AS TIME GOES
BY TONIGHT.

GFS MOS LOWS TONIGHT LOOK REASONABLE BASED ON LOW LEVEL THICKNESS
PROGS.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
ISSUED AT 239 PM EDT MON MAY 20 2013

MAIN FEATURE DURING THIS PERIOD WILL BE THE LARGE UPPER LOW OVER THE
PLAINS THAT IS EXPECTED TO GRADUALLY OPEN UP AND MOVE INTO THE
MIDWEST BY THURSDAY...KEEPING THE SHORT TERM UNSETTLED.

DETAILS REVOLVING AROUND THE FRONTAL BOUNDARY OR ANY EFFECTIVE
OUTFLOW BOUNDARIES TO FOCUS CONVECTION ON OVER THE NEXT COUPLE OF
DAYS IS STILL MURKY...WITH SEVERAL ROUNDS OF CONVECTION EXPECTED.
ACTUAL COLD FRONT MAY NOT PASS UNTIL WEDNESDAY NIGHT OR THURSDAY
MORNING. APPEARS FROM THE MODEL DATA...THE BEST PRECIPITATION
SIGNALS ARRIVE TUESDAY NIGHT AND WEDNESDAY...SO WILL GO WITH THE
HIGHEST POPS DURING THOSE TIMES. WILL GO WITH CHANCE POPS IN THE
OTHER PERIODS FOR NOW.

AT THIS POINT...THE COMBINATION OF LAPSE RATES AND DEEP LAYER SHEAR
SUGGEST THAT TUESDAY MAY HAVE THE BEST POTENTIAL FOR SEVERE
CONVECTION OVER THE NEXT COUPLE OF DAYS. BY WEDNESDAY...LAPSE RATES
BECOME POORER...WHICH SHOULD HELP TO DIMINISH THE SEVERE THREAT BY
THAT TIME.

GIVEN PROGGED LOW LEVEL THICKNESSES AND EXPECTED CONVECTION OR CLOUD
COVER...THE GFS MOS HIGHS FOR TUESDAY AND WEDNESDAY LOOK A LITTLE
WARM. WILL NUDGE THE NUMBERS DOWN A FEW DEGREES. GUIDANCE LOWS LOOK
OK.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ISSUED AT 239 PM EDT MON MAY 20 2013

DRY WEATHER IS ANTICIPATED DURING THIS PERIOD AND THE ECMWF AND
THE GFS BOTH AGREE IN BUILDING A LARGE RIDGE OVER THE CENTRAL
PLAINS ACROSS INDIANA DURING THIS TIME. A SHORT WAVE TROUGH WILL
EXIT THE AREA ON THURSDAY...ALLOWING THE LEE SIDE OF THE RIDGE AND
ASSOCIATED SUBSIDENCE ON NORTHWEST WIND TO ARRIVE ACROSS THE AREA
FOR FRIDAY AND SATURDAY. THIS WILL RESULT IN DRY WEATHER WITH
TEMPS AT OR BELOW SEASONABLE NORMALS AS DUE TO THE COOL CANADIAN
AIR.

TEMPS WILL GRADUALLY WARM ON SUNDAY AND MONDAY AS THE RIDGE
PROGRESSES EASTWARD AND WARMER...MORE HUMID AIR ARRIVES ON
SOUTHERLY WINDS ON THE BACK OF THE RIDGE.

&&

.AVIATION /DISCUSSION FOR THE 210000Z TAF ISSUANCE/...

ISSUED AT 700 PM EDT MON MAY 20 2013

CONDITIONS SHOULD BE VFR THROUGH THE TAF PERIOD EXCEPT PERHAPS IN
THUNDERSTORMS. LOOKS LIKE THIS EVENING WILL BE QUIET WITH
THUNDERSTORM CHANCES INCREASING AFTER 06Z ESPECIALLY AT HUF AND LAF.
ACTIVITY EXPECTED TO COME FROM CURRENT MISSOURI STORMS. FOR
NOW...WILL GO WITH VCTS AND CONSIDER TEMPO GROUPS LATER IF ACTIVITY
CAN BE CONFIDENTLY TIMED ACROSS ONE OR MORE OF THE TERMINALS. SOUTH
WINDS SHOULD STAY UP AROUND 10 KNOTS TONIGHT PERHAPS GUSTING TO NEAR
20 AT TIMES. AFTER 15Z TUESDAY...SHOULD SEE SOME BREAKS IN THE
CLOUDS WHICH SHOULD ALLOW GOOD MIXING AND SOUTHWEST WINDS NEAR 20
KNOTS AND GUSTING TO NEAR 30 KNOTS. COULD ALSO SEE SOME MORE
THUNDERSTORM ACTIVITY...BUT BETTER CHANCE AFTER 00Z WEDNESDAY...SO
WILL ONLY GO WITH VCTS FOR NOW AFTER 19Z EXCEPT PROB30 AT IND AFTER
00Z WEDNESDAY.

&&

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

$$

SYNOPSIS...JAS
NEAR TERM...JAS
SHORT TERM...JAS
LONG TERM....PUMA
AVIATION...MK

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

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

000
FXUS63 KIWX 202134
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
534 PM EDT MON MAY 20 2013

.SYNOPSIS...
ISSUED AT 532 PM EDT MON MAY 20 2013

SHOWER AND THUNDERSTORM CHANCES WILL CONTINUE TO INCREASE TONIGHT THROUGH
WEDNESDAY...WITH A FEW SHOWERS POSSIBLY LINGERING INTO THURSDAY.
THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS THIS EVENING
THROUGH TUESDAY NIGHT. DRIER AND COOLER WEATHER IS ANTICIPATED
LATE THIS WEEK INTO NEXT WEEKEND.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 305 PM EDT MON MAY 20 2013

REMNANT GRAVITY WAVE FROM OVERNIGHT CONVECTION AND
ASSOCIATED WITH A ~10F DEGREE DEWPOINT DROP IN ITS WAKE HAS WASHED
OUT AS IT MOVED INTO OUR FORECAST AREA. THIS HAS KEPT MODERATELY
UNSTABLE AIRMASS ACROSS THE EASTERN TWO-THIRDS OF OUR FORECAST AREA.
ADDED SLIGHT CHANCE POPS FOR THE EAST THIS EVENING AS CONVECTION
COULD FIRE ALONG OR IN FRONT OF THIS BOUNDARY WHERE THE AIRMASS IS
CHARACTERIZED BY SBCAPE VALUES IN EXCESS OF 3000 J/KG. THE GREATEST
LIMITING FACTOR IS THE LACK OF SIGNIFICANT FORCING...ALTHOUGH
CONVECTION ACROSS MICHIGAN AND ADDITIONAL CONVECTION FIRING ALONG
THE BOUNDARY ACROSS EASTERN ILLINOIS AT 1830Z INDICATES THIS
BOUNDARY MAY PROVIDE JUST ENOUGH FORCED ASCENT FOR ISOLATED STORM
DEVELOPMENT.

STILL SOME UNCERTAINTY REGARDING CONVECTIVE EVOLUTION AND IMPACTS
ACROSS OUR AREA TONIGHT. DECAYING STORM CLUSTER ACROSS WESTERN
ILLINOIS SHOULD CONTINUE ITS WEAKENING TREND AS IT MOVES INTO A
MOISTURE VOID AREA ACROSS ILLINOIS WITH SURFACE DEWPOINTS IN THE
UPPER 50S. WITH THAT BEING SAID...SOME SHORT TERM MODEL GUIDANCE IS
INDICATING A QUICK RECOVERY OF THE MOISTURE PROFILE IN THAT AREA AS
850 MOISTURE TRANSPORT INCREASES THIS AFTERNOON. IF THE AIRMASS
AHEAD OF THESE STORMS CAN DESTABILIZE OVER THE NEXT FEW HOURS...AS
THE HRRR SUGGESTS...UPSCALE GROWTH OF THAT CLUSTER AS WELL AS
ADDITIONAL STORM DEVELOPMENT MAY TRACK ACROSS THE NORTHWEST PORTION
OF OUR FORECAST AREA DURING THE LATE EVENING. IF STORMS CAN
DEVELOP...SEVERE POTENTIAL DOES EXIST AS 0-6 KM SHEAR OF 35-45 KNOTS
OVERSPREADS THE NORTHWEST PORTION OF OUR FORECAST AREA WITH THE MAIN
THREATS BEING SEVERE HAIL AND WIND.

REMAIN MORE CONFIDENT IN PRECIPITATION CHANCES AFTER 06Z WHEN
REMNANT CONVECTION FROM MISSOURI TRACKS TOWARDS THE AREA. SEVERE
THREAT WILL BE MINIMAL WITH THIS CONVECTION DUE TO ITS TIMING DURING
THE EARLY MORNING HOURS.

TUESDAY LOOKS TO BE COOLER THAN TODAY AS LITTLE SUN WILL BE SEEN
ACROSS OUR FORECAST AREA DUE TO CLOUD DEBRIS FROM FROM OVERNIGHT
CONVECTION AS WELL AS ADDITIONAL DYNAMIC LIFT FROM 40-50 KT LLJ.
SEVERE THREAT DOES EXIST IF A FEW BREAKS IN THE CLOUDS CAN PROVIDE
SIGNIFICANT SURFACE HEATING FOR EVEN MARGINAL SURFACE BASED
INSTABILITY. THE MAIN THREAT WILL BE LARGE HAIL AND DAMAGING WINDS
AS UNIDIRECTIONAL 35-40 KNOT SHEAR OVERSPREADS THE AREA.

&&

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 305 PM EDT MON MAY 20 2013

ONE OR TWO MORE ROUNDS OF CONVECTION TO BEGIN THE FORECAST PERIOD.
MODELS IN PRETTY GOOD AGREEMENT IN SHORT WAVE COMING OUT OF BASE OF
CLOSED LOW AND IMPACTING THE AREA TUE NIGHT. GOOD SUPPORT WILL
ACCOMPANY THIS FEATURE AND 50-60KT MID LEVEL SPEED MAX WILL COMBINE
WITH INFLUX OF LOW LEVEL MOISTURE WITH AT LEAST SUFFICIENT
INSTABILITY TO INITIATE OR MAINTAIN CONVECTION. UNIDIRECTIONAL WIND
PROFILE WITH AROUND 30KT OF SPEED SHEAR WILL HAVE DAMAGING WINDS AS
THE MAIN SEVERE THREAT. CLOSED LOW FINALLY OPENS UP AND WILL MOVE
EASTWARD INTO THE GREAT LAKES REGION WEDNESDAY NIGHT...BRINGING SFC
LOW AND MAIN COLD FRONT WITH IT. MODELS OFFERING VARYING
TIMING/PLACEMENT OF THESE FEATURES BUT ONE MORE ROUND OF CONVECTION
POSSIBLE WEDNESDAY...MAINLY FOR THE EASTERN HALF OF THE CWA. UPPER
TROF AXIS ROTATES THROUGH THE AREA WEDNESDAY NIGHT INTO THURSDAY
KEEPING CHANCE FOR A FEW SHOWERS BEFORE COOLER DRIER CANADIAN HIGH
PRESSURE BEGINS TO BUILD INTO THE GREAT LAKES REGION ON FRIDAY. THIS
WILL PROVIDE A NICE START TO THE HOLIDAY WEEKEND...QUESTIONS REMAIN
AS TO WHETHER IT WILL LAST THROUGH MONDAY. SFC RIDGE AXIS WILL
PROGRESS EASTWARD SUNDAY AND MONDAY...PLACING OUR AREA ON THE
WESTERN PERIPHERY OF THE HIGH WHILE MEDIUM RANGE MODELS ATTEMPTING
TO BRING SHORT WAVE ENERGY DOWN IN NW FLOW. GETTING BETTER MODEL
AGREEMENT WITH THIS SOLN BUT LOTS OF VARIATION IN TIMING AND
PLACEMENT. ENSEMBLE GUIDANCE NEAR OR MOSTLY BELOW CLIMO FOR POPS AS
WELL SO WILL STILL HOLD OUT FOR DRY FORECAST FOR AT LEAST ONE MORE
ISSUANCE. TEMPS TRENDING SEASONABLY COOLER WITH AOB NORMAL FOR MOST

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 128 PM EDT MON MAY 20 2013

VFR CONDITIONS EXPECTED FOR THE REST OF TODAY AND INTO
THE OVERNIGHT HOURS. SLIGHT CHANCE THAT A STRAY SHOWER OR ISOLATED
STORM COULD POP UP NEAR KFWA...BUT CONFIDENCE WAS TOO LOW FOR
INCLUSION IN 18Z TAF ISSUANCE. STORMS WILL FIRE ACROSS MISSOURI
TODAY AND WILL LIKELY TRACK INTO NORTHERN INDIANA DURING THE EARLY
MORNING HOURS. THIS THREAT IS GREATEST AT KSBN. WILL WAIT FOR LATER
TAF ISSUANCES BEFORE INCLUDING THESE STORMS AS SUBTLE TIMING
DIFFERENCES AND EXACT LOCATION WILL NOT BE KNOWN UNTIL THE
CONVECTION HAS FIRED AND BEGINS TRACKING TOWARDS THE AREA.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...STEINWEDEL/KG
SHORT TERM...BENTLEY
LONG TERM...JAL
AVIATION...BENTLEY


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIND 202033
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
430 PM EDT MON MAY 20 2013

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

&&

.SYNOPSIS...
ISSUED AT 239 PM EDT MON MAY 20 2013

A LARGE UPPER LOW CURRENTLY OVER THE PLAINS IS EXPECTED TO BRING
UNSETTLED WEATHER TO THE AREA THROUGH THURSDAY AS IT SLOWLY MOVES
EAST AND WEAKENS WITH TIME. IN THE WAKE OF THIS SYSTEM...HIGH
PRESSURE IS EXPECTED TO BUILD INTO THE AREA OVER THE WEEKEND AND
INTO EARLY NEXT WEEK.

&&

.NEAR TERM /REST OF THIS AFTERNOON AND TONIGHT/...
ISSUED AT 239 PM EDT MON MAY 20 2013

DEWPOINT DISCONTINUITY LINGERS OVER THE NORTHWEST ZONES...WITH
DEWPOINTS MIXING OUT INTO THE 50S OVER NORTHERN ILLINOIS. THIS MAY
BE EITHER THE REMNANTS OF AN OUTFLOW OR A FRONTAL SYSTEM. IN ANY
EVENT...AIR MASS OVER THE LOCAL AREA CONTINUES TO BE CAPPED...BUT
VERY UNSTABLE. SHORT TERM MODEL DATA SUGGEST THIS CAP MAY WEAKEN
AROUND 202200Z OR SO...LEADING TO THE POTENTIAL FOR THUNDERSTORM
DEVELOPMENT NEAR THIS DISCONTINUITY BY EARLY EVENING.
HOWEVER...THERE IS A QUESTION WHETHER THIS CAP WILL ACTUALLY BREAK.
MODEL DATA ALSO BRING IN AN AREA OF ORGANIZED LIFT DURING THE PRE
DAWN HOURS OF TUESDAY...PROBABLY RELATED TO CONVECTION THAT IS
EXPECTED TO DEVELOP FARTHER WEST LATER THIS AFTERNOON/EVENING.
THIS MAY RESULT IN ANOTHER ENHANCED CHANCE FOR CONVECTION BY EARLY
MORNING TUESDAY. DUE TO QUESTIONS REVOLVING AROUND THE CAP AND ANY
FUTURE STORM DEVELOPMENT...WILL KEEP POPS IN THE CHANCE CATEGORY
TONIGHT...HIGHEST IN THE WEST/NORTHWEST.

LAPSE RATE REMAIN QUITE FAVORABLE FOR SEVERE CONVECTION TONIGHT.
DEEP LAYER SHEAR...INITIALLY RATHER WEAK THIS EVENING...IS EXPECTED
TO STRENGTHEN LATER TONIGHT. AS A RESULT...THINK THE POTENTIAL FOR
ORGANIZED SEVERE CONVECTION SHOULD GRADUALLY INCREASE AS TIME GOES
BY TONIGHT.

GFS MOS LOWS TONIGHT LOOK REASONABLE BASED ON LOW LEVEL THICKNESS
PROGS.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
ISSUED AT 239 PM EDT MON MAY 20 2013

MAIN FEATURE DURING THIS PERIOD WILL BE THE LARGE UPPER LOW OVER THE
PLAINS THAT IS EXPECTED TO GRADUALLY OPEN UP AND MOVE INTO THE
MIDWEST BY THURSDAY...KEEPING THE SHORT TERM UNSETTLED.

DETAILS REVOLVING AROUND THE FRONTAL BOUNDARY OR ANY EFFECTIVE
OUTFLOW BOUNDARIES TO FOCUS CONVECTION ON OVER THE NEXT COUPLE OF
DAYS IS STILL MURKY...WITH SEVERAL ROUNDS OF CONVECTION EXPECTED.
ACTUAL COLD FRONT MAY NOT PASS UNTIL WEDNESDAY NIGHT OR THURSDAY
MORNING. APPEARS FROM THE MODEL DATA...THE BEST PRECIPITATION
SIGNALS ARRIVE TUESDAY NIGHT AND WEDNESDAY...SO WILL GO WITH THE
HIGHEST POPS DURING THOSE TIMES. WILL GO WITH CHANCE POPS IN THE
OTHER PERIODS FOR NOW.

AT THIS POINT...THE COMBINATION OF LAPSE RATES AND DEEP LAYER SHEAR
SUGGEST THAT TUESDAY MAY HAVE THE BEST POTENTIAL FOR SEVERE
CONVECTION OVER THE NEXT COUPLE OF DAYS. BY WEDNESDAY...LAPSE RATES
BECOME POORER...WHICH SHOULD HELP TO DIMINISH THE SEVERE THREAT BY
THAT TIME.

GIVEN PROGGED LOW LEVEL THICKNESSES AND EXPECTED CONVECTION OR CLOUD
COVER...THE GFS MOS HIGHS FOR TUESDAY AND WEDNESDAY LOOK A LITTLE
WARM. WILL NUDGE THE NUMBERS DOWN A FEW DEGREES. GUIDANCE LOWS LOOK
OK.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ISSUED AT 239 PM EDT MON MAY 20 2013

DRY WEATHER IS ANTICIPATED DURING THIS PERIOD AND THE ECMWF AND
THE GFS BOTH AGREE IN BUILDING A LARGE RIDGE OVER THE CENTRAL
PLAINS ACROSS INDIANA DURING THIS TIME. A SHORT WAVE TROUGH WILL
EXIT THE AREA ON THURSDAY...ALLOWING THE LEE SIDE OF THE RIDGE AND
ASSOCIATED SUBSIDENCE ON NORTHWEST WIND TO ARRIVE ACROSS THE AREA
FOR FRIDAY AND SATURDAY. THIS WILL RESULT IN DRY WEATHER WITH
TEMPS AT OR BELOW SEASONABLE NORMALS AS DUE TO THE COOL CANADIAN
AIR.

TEMPS WILL GRADUALLY WARM ON SUNDAY AND MONDAY AS THE RIDGE
PROGRESSES EASTWARD AND WARMER...MORE HUMID AIR ARRIVES ON
SOUTHERLY WINDS ON THE BACK OF THE RIDGE.

&&

.AVIATION /DISCUSSION FOR THE 202100Z IND TAF UPDATE/...

ISSUED AT 430 PM EDT MON MAY 20 2013

MADE TWEAK TO WINDS. OTHERWISE...BROKEN LINE OF THUNDERSTORMS STILL
LOOKS LIKE IT WILL BE IN THE VICINITY OF IND AROUND 22Z.

PREVIOUS DISCUSSION FOLLOWS...

VFR CONDITIONS ARE EXPECTED FOR MUCH OF THIS TAF PERIOD.

FORECAST SOUNDINGS ACROSS THE AREA INDICATE A DECENT MID LEVEL CAP
IN PLACE ACROSS THE AREA THAT SHOULD INHIBIT CONVECTION FOR
THE FIRST FEW HOURS OF THE TAF PERIOD. HOWEVER...CAPPING APPEARS TO
ERODE LATE IN THE AFTERNOON. THUS HAVE CONTINUED TO KEEP A
MENTION OF VCTS DUE TO DAYTIME HEATING IN THE VERY WARM AND
UNSTABLE AIR MASS THAT REMAINS IN PLACE ACROSS CENTRAL INDIANA.

ANY CONVECTIVE ACTIVITY SHOULD WAVE IN THE EVENING AS HEATING IS
LOST...HOWEVER GFS AND ECMWF SUGGEST CONVECTION WEST OF
INDIANA...OVER MISSOURI AND ILLINOIS MAY DRIFT INTO WESTERN PARTS
OF THE FORECAST AREA OVERNIGHT. AGAIN CONFIDENCE REMAINS LOW WITH
THESE FEATURES...SO FOR NOW JUST A VCTS MENTION.

GOOD MIXING OVERNIGHT SHOULD PREVENT MUCH IN THE WAY OF FOG
FORMATION.

AS THAT WAVE DEPARTS ON TUESDAY MORNING...THE WARM AND UNSTABLE
AIR MASS WILL REMAIN IN PLACE ACROSS CENTRAL INDIANA AS YET
ANOTHER SHORT WAVE APPROACHES FROM THE WEST...PROVIDING MORE
SUPPORT FOR CONVECTION ON TUESDAY AFTERNOON AND TUESDAY NIGHT.

&&

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

$$

SYNOPSIS...JAS
NEAR TERM...JAS
SHORT TERM...JAS
LONG TERM....PUMA
AVIATION...JP/MK

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

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

000
FXUS63 KIWX 201907
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
307 PM EDT MON MAY 20 2013

.SYNOPSIS...
ISSUED AT 1052 AM EDT MON MAY 20 2013

A SLOW MOVING LOW PRESSURE SYSTEM WILL BRING INCREASING CHANCES
FOR SHOWERS AND THUNDERSTORMS LATER TODAY THROUGH WEDNESDAY...WITH
A FEW SHOWERS POSSIBLY LINGERING INTO THURSDAY. THERE IS A SLIGHT
RISK FOR SEVERE THUNDERSTORMS THIS AFTERNOON THROUGH TUESDAY
NIGHT. DRIER AND COOLER WEATHER IS ANTICIPATED LATE THIS WEEK
INTO NEXT WEEKEND.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 305 PM EDT MON MAY 20 2013

REMNANT GRAVITY WAVE FROM OVERNIGHT CONVECTION AND
ASSOCIATED WITH A ~10F DEGREE DEWPOINT DROP IN ITS WAKE HAS WASHED
OUT AS IT MOVED INTO OUR FORECAST AREA. THIS HAS KEPT MODERATELY
UNSTABLE AIRMASS ACROSS THE EASTERN TWO-THIRDS OF OUR FORECAST AREA.
ADDED SLIGHT CHANCE POPS FOR THE EAST THIS EVENING AS CONVECTION
COULD FIRE ALONG OR IN FRONT OF THIS BOUNDARY WHERE THE AIRMASS IS
CHARACTERIZED BY SBCAPE VALUES IN EXCESS OF 3000 J/KG. THE GREATEST
LIMITING FACTOR IS THE LACK OF SIGNIFICANT FORCING...ALTHOUGH
CONVECTION ACROSS MICHIGAN AND ADDITIONAL CONVECTION FIRING ALONG
THE BOUNDARY ACROSS EASTERN ILLINOIS AT 1830Z INDICATES THIS
BOUNDARY MAY PROVIDE JUST ENOUGH FORCED ASCENT FOR ISOLATED STORM
DEVELOPMENT.

STILL SOME UNCERTAINTY REGARDING CONVECTIVE EVOLUTION AND IMPACTS
ACROSS OUR AREA TONIGHT. DECAYING STORM CLUSTER ACROSS WESTERN
ILLINOIS SHOULD CONTINUE ITS WEAKENING TREND AS IT MOVES INTO A
MOISTURE VOID AREA ACROSS ILLINOIS WITH SURFACE DEWPOINTS IN THE
UPPER 50S. WITH THAT BEING SAID...SOME SHORT TERM MODEL GUIDANCE IS
INDICATING A QUICK RECOVERY OF THE MOISTURE PROFILE IN THAT AREA AS
850 MOISTURE TRANSPORT INCREASES THIS AFTERNOON. IF THE AIRMASS
AHEAD OF THESE STORMS CAN DESTABILIZE OVER THE NEXT FEW HOURS...AS
THE HRRR SUGGESTS...UPSCALE GROWTH OF THAT CLUSTER AS WELL AS
ADDITIONAL STORM DEVELOPMENT MAY TRACK ACROSS THE NORTHWEST PORTION
OF OUR FORECAST AREA DURING THE LATE EVENING. IF STORMS CAN
DEVELOP...SEVERE POTENTIAL DOES EXIST AS 0-6 KM SHEAR OF 35-45 KNOTS
OVERSPREADS THE NORTHWEST PORTION OF OUR FORECAST AREA WITH THE MAIN
THREATS BEING SEVERE HAIL AND WIND.

REMAIN MORE CONFIDENT IN PRECIPITATION CHANCES AFTER 06Z WHEN
REMNANT CONVECTION FROM MISSOURI TRACKS TOWARDS THE AREA. SEVERE
THREAT WILL BE MINIMAL WITH THIS CONVECTION DUE TO ITS TIMING DURING
THE EARLY MORNING HOURS.

TUESDAY LOOKS TO BE COOLER THAN TODAY AS LITTLE SUN WILL BE SEEN
ACROSS OUR FORECAST AREA DUE TO CLOUD DEBRIS FROM FROM OVERNIGHT
CONVECTION AS WELL AS ADDITIONAL DYNAMIC LIFT FROM 40-50 KT LLJ.
SEVERE THREAT DOES EXIST IF A FEW BREAKS IN THE CLOUDS CAN PROVIDE
SIGNIFICANT SURFACE HEATING FOR EVEN MARGINAL SURFACE BASED
INSTABILITY. THE MAIN THREAT WILL BE LARGE HAIL AND DAMAGING WINDS
AS UNIDIRECTIONAL 35-40 KNOT SHEAR OVERSPREADS THE AREA.

&&

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 305 PM EDT MON MAY 20 2013

ONE OR TWO MORE ROUNDS OF CONVECTION TO BEGIN THE FORECAST PERIOD.
MODELS IN PRETTY GOOD AGREEMENT IN SHORT WAVE COMING OUT OF BASE OF
CLOSED LOW AND IMPACTING THE AREA TUE NIGHT. GOOD SUPPORT WILL
ACCOMPANY THIS FEATURE AND 50-60KT MID LEVEL SPEED MAX WILL COMBINE
WITH INFLUX OF LOW LEVEL MOISTURE WITH AT LEAST SUFFICIENT
INSTABILITY TO INITIATE OR MAINTAIN CONVECTION. UNIDIRECTIONAL WIND
PROFILE WITH AROUND 30KT OF SPEED SHEAR WILL HAVE DAMAGING WINDS AS
THE MAIN SEVERE THREAT. CLOSED LOW FINALLY OPENS UP AND WILL MOVE
EASTWARD INTO THE GREAT LAKES REGION WEDNESDAY NIGHT...BRINGING SFC
LOW AND MAIN COLD FRONT WITH IT. MODELS OFFERING VARYING
TIMING/PLACEMENT OF THESE FEATURES BUT ONE MORE ROUND OF CONVECTION
POSSIBLE WEDNESDAY...MAINLY FOR THE EASTERN HALF OF THE CWA. UPPER
TROF AXIS ROTATES THROUGH THE AREA WEDNESDAY NIGHT INTO THURSDAY
KEEPING CHANCE FOR A FEW SHOWERS BEFORE COOLER DRIER CANADIAN HIGH
PRESSURE BEGINS TO BUILD INTO THE GREAT LAKES REGION ON FRIDAY. THIS
WILL PROVIDE A NICE START TO THE HOLIDAY WEEKEND...QUESTIONS REMAIN
AS TO WHETHER IT WILL LAST THROUGH MONDAY. SFC RIDGE AXIS WILL
PROGRESS EASTWARD SUNDAY AND MONDAY...PLACING OUR AREA ON THE
WESTERN PERIPHERY OF THE HIGH WHILE MEDIUM RANGE MODELS ATTEMPTING
TO BRING SHORT WAVE ENERGY DOWN IN NW FLOW. GETTING BETTER MODEL
AGREEMENT WITH THIS SOLN BUT LOTS OF VARIATION IN TIMING AND
PLACEMENT. ENSEMBLE GUIDANCE NEAR OR MOSTLY BELOW CLIMO FOR POPS AS
WELL SO WILL STILL HOLD OUT FOR DRY FORECAST FOR AT LEAST ONE MORE
ISSUANCE. TEMPS TRENDING SEASONABLY COOLER WITH AOB NORMAL FOR MOST
OF THE FCST PERIOD.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 128 PM EDT MON MAY 20 2013

VFR CONDITIONS EXPECTED FOR THE REST OF TODAY AND INTO
THE OVERNIGHT HOURS. SLIGHT CHANCE THAT A STRAY SHOWER OR ISOLATED
STORM COULD POP UP NEAR KFWA...BUT CONFIDENCE WAS TOO LOW FOR
INCLUSION IN 18Z TAF ISSUANCE. STORMS WILL FIRE ACROSS MISSOURI
TODAY AND WILL LIKELY TRACK INTO NORTHERN INDIANA DURING THE EARLY
MORNING HOURS. THIS THREAT IS GREATEST AT KSBN. WILL WAIT FOR LATER
TAF ISSUANCES BEFORE INCLUDING THESE STORMS AS SUBTLE TIMING
DIFFERENCES AND EXACT LOCATION WILL NOT BE KNOWN UNTIL THE
CONVECTION HAS FIRED AND BEGINS TRACKING TOWARDS THE AREA.



&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...STEINWEDEL
SHORT TERM...BENTLEY
LONG TERM...JAL
AVIATION...BENTLEY


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIND 201844
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
244 PM EDT MON MAY 20 2013

.UPDATE...
THE SYNOPSIS...NEAR TERM...SHORT TERM AND LONG TERM SECTIONS HAVE
BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 239 PM EDT MON MAY 20 2013

A LARGE UPPER LOW CURRENTLY OVER THE PLAINS IS EXPECTED TO BRING
UNSETTLED WEATHER TO THE AREA THROUGH THURSDAY AS IT SLOWLY MOVES
EAST AND WEAKENS WITH TIME. IN THE WAKE OF THIS SYSTEM...HIGH
PRESSURE IS EXPECTED TO BUILD INTO THE AREA OVER THE WEEKEND AND
INTO EARLY NEXT WEEK.

&&

.NEAR TERM /REST OF THIS AFTERNOON AND TONIGHT/...
ISSUED AT 239 PM EDT MON MAY 20 2013

DEWPOINT DISCONTINUITY LINGERS OVER THE NORTHWEST ZONES...WITH
DEWPOINTS MIXING OUT INTO THE 50S OVER NORTHERN ILLINOIS. THIS MAY
BE EITHER THE REMNANTS OF AN OUTFLOW OR A FRONTAL SYSTEM. IN ANY
EVENT...AIR MASS OVER THE LOCAL AREA CONTINUES TO BE CAPPED...BUT
VERY UNSTABLE. SHORT TERM MODEL DATA SUGGEST THIS CAP MAY WEAKEN
AROUND 202200Z OR SO...LEADING TO THE POTENTIAL FOR THUNDERSTORM
DEVELOPMENT NEAR THIS DISCONTINUITY BY EARLY EVENING.
HOWEVER...THERE IS A QUESTION WHETHER THIS CAP WILL ACTUALLY BREAK.
MODEL DATA ALSO BRING IN AN AREA OF ORGANIZED LIFT DURING THE PRE
DAWN HOURS OF TUESDAY...PROBABLY RELATED TO CONVECTION THAT IS
EXPECTED TO DEVELOP FARTHER WEST LATER THIS AFTERNOON/EVENING.
THIS MAY RESULT IN ANOTHER ENHANCED CHANCE FOR CONVECTION BY EARLY
MORNING TUESDAY. DUE TO QUESTIONS REVOLVING AROUND THE CAP AND ANY
FUTURE STORM DEVELOPMENT...WILL KEEP POPS IN THE CHANCE CATEGORY
TONIGHT...HIGHEST IN THE WEST/NORTHWEST.

LAPSE RATE REMAIN QUITE FAVORABLE FOR SEVERE CONVECTION TONIGHT.
DEEP LAYER SHEAR...INITIALLY RATHER WEAK THIS EVENING...IS EXPECTED
TO STRENGTHEN LATER TONIGHT. AS A RESULT...THINK THE POTENTIAL FOR
ORGANIZED SEVERE CONVECTION SHOULD GRADUALLY INCREASE AS TIME GOES
BY TONIGHT.

GFS MOS LOWS TONIGHT LOOK REASONABLE BASED ON LOW LEVEL THICKNESS
PROGS.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
ISSUED AT 239 PM EDT MON MAY 20 2013

MAIN FEATURE DURING THIS PERIOD WILL BE THE LARGE UPPER LOW OVER THE
PLAINS THAT IS EXPECTED TO GRADUALLY OPEN UP AND MOVE INTO THE
MIDWEST BY THURSDAY...KEEPING THE SHORT TERM UNSETTLED.

DETAILS REVOLVING AROUND THE FRONTAL BOUNDARY OR ANY EFFECTIVE
OUTFLOW BOUNDARIES TO FOCUS CONVECTION ON OVER THE NEXT COUPLE OF
DAYS IS STILL MURKY...WITH SEVERAL ROUNDS OF CONVECTION EXPECTED.
ACTUAL COLD FRONT MAY NOT PASS UNTIL WEDNESDAY NIGHT OR THURSDAY
MORNING. APPEARS FROM THE MODEL DATA...THE BEST PRECIPITATION
SIGNALS ARRIVE TUESDAY NIGHT AND WEDNESDAY...SO WILL GO WITH THE
HIGHEST POPS DURING THOSE TIMES. WILL GO WITH CHANCE POPS IN THE
OTHER PERIODS FOR NOW.

AT THIS POINT...THE COMBINATION OF LAPSE RATES AND DEEP LAYER SHEAR
SUGGEST THAT TUESDAY MAY HAVE THE BEST POTENTIAL FOR SEVERE
CONVECTION OVER THE NEXT COUPLE OF DAYS. BY WEDNESDAY...LAPSE RATES
BECOME POORER...WHICH SHOULD HELP TO DIMINISH THE SEVERE THREAT BY
THAT TIME.

GIVEN PROGGED LOW LEVEL THICKNESSES AND EXPECTED CONVECTION OR CLOUD
COVER...THE GFS MOS HIGHS FOR TUESDAY AND WEDNESDAY LOOK A LITTLE
WARM. WILL NUDGE THE NUMBERS DOWN A FEW DEGREES. GUIDANCE LOWS LOOK
OK.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ISSUED AT 239 PM EDT MON MAY 20 2013

DRY WEATHER IS ANTICIPATED DURING THIS PERIOD AND THE ECMWF AND
THE GFS BOTH AGREE IN BUILDING A LARGE RIDGE OVER THE CENTRAL
PLAINS ACROSS INDIANA DURING THIS TIME. A SHORT WAVE TROUGH WILL
EXIT THE AREA ON THURSDAY...ALLOWING THE LEE SIDE OF THE RIDGE AND
ASSOCIATED SUBSIDENCE ON NORTHWEST WIND TO ARRIVE ACROSS THE AREA
FOR FRIDAY AND SATURDAY. THIS WILL RESULT IN DRY WEATHER WITH
TEMPS AT OR BELOW SEASONABLE NORMALS AS DUE TO THE COOL CANADIAN
AIR.

TEMPS WILL GRADUALLY WARM ON SUNDAY AND MONDAY AS THE RIDGE
PROGRESSES EASTWARD AND WARMER...MORE HUMID AIR ARRIVES ON
SOUTHERLY WINDS ON THE BACK OF THE RIDGE.

&&

.AVIATION /DISCUSSION FOR THE 201800Z TAFS/...

ISSUED AT 1237 PM EDT MON MAY 20 2013

VFR CONDITIONS ARE EXPECTED FOR MUCH OF THIS TAF PERIOD.

FORECAST SOUNDINGS ACROSS THE AREA INDICATE A DECENT MID LEVEL CAP
IN PLACE ACROSS THE AREA THAT SHOULD INHIBIT CONVECTION FOR
THE FIRST FEW HOURS OF THE TAF PERIOD. HOWEVER...CAPPING APPEARS TO
ERODE LATE IN THE AFTERNOON. THUS HAVE CONTINUED TO KEEP A
MENTION OF VCTS DUE TO DAYTIME HEATING IN THE VERY WARM AND
UNSTABLE AIR MASS THAT REMAINS IN PLACE ACROSS CENTRAL INDIANA.

ANY CONVECTIVE ACTIVITY SHOULD WAVE IN THE EVENING AS HEATING IS
LOST...HOWEVER GFS AND ECMWF SUGGEST CONVECTION WEST OF
INDIANA...OVER MISSOURI AND ILLINOIS MAY DRIFT INTO WESTERN PARTS
OF THE FORECAST AREA OVERNIGHT. AGAIN CONFIDENCE REMAINS LOW WITH
THESE FEATURES...SO FOR NOW JUST A VCTS MENTION.

GOOD MIXING OVERNIGHT SHOULD PREVENT MUCH IN THE WAY OF FOG FORMATION.

AS THAT WAVE DEPARTS ON TUESDAY MORNING...THE WARM AND UNSTABLE
AIR MASS WILL REMAIN IN PLACE ACROSS CENTRAL INDIANA AS YET
ANOTHER SHORT WAVE APPROACHES FROM THE WEST...PROVIDING MORE
SUPPORT FOR CONVECTION ON TUESDAY AFTERNOON AND TUESDAY NIGHT.

&&

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

$$

SYNOPSIS...JAS
NEAR TERM...JAS
SHORT TERM...JAS
LONG TERM....PUMA
AVIATION...JP

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

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

000
FXUS63 KIWX 201729
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
129 PM EDT MON MAY 20 2013

.SYNOPSIS...
ISSUED AT 1052 AM EDT MON MAY 20 2013

A SLOW MOVING LOW PRESSURE SYSTEM WILL BRING INCREASING CHANCES
FOR SHOWERS AND THUNDERSTORMS LATER TODAY THROUGH WEDNESDAY...WITH
A FEW SHOWERS POSSIBLY LINGERING INTO THURSDAY. THERE IS A SLIGHT
RISK FOR SEVERE THUNDERSTORMS THIS AFTERNOON THROUGH TUESDAY
NIGHT. DRIER AND COOLER WEATHER IS ANTICIPATED LATE THIS WEEK
INTO NEXT WEEKEND.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM EDT MON MAY 20 2013

DEEP REX BLOCKED CUTOFF LOW CNTRD OVR NRN NE THIS
MORNING WILL MOVE LTL THIS PD. THUS W/LTL CHG IN JET
STRUCTURE/POSITIONING ALOFT XPC CONVN WILL ONCE AGAIN STAY FOCUSED
WWD INVOF MS VALLEY.

LG SCALE GRAVITY WAVE EMINATING FM SLOWLY DECAYING CONVN ACRS WRN
IL SWWD INTO ERN MO WILL CONT EWD THIS MORNING. HWVR DOWNSTREAM
AIRMASS OF MUCH POORER QUALITY AS EVIDENT IN 00Z RAOBS AND
W/LLJ/MID LVL JET STREAK AXIS REMAINING ANCHORED TO THE WEST SEE
LTL EVIDENCE OF A SUFFICIENT SYNOPIC TRIGGER FOR AFTN CONVN AGAIN
TDA ESP IN LIGHT OF 00Z MODEL GUIDANCE SFC MSTR BIAS. WILL RETAIN
A LWR BOUND CHC MENTION NW HALF IN PROXIMITY TO EWD EDGE OF BTR LL
MASS FLUX THIS AFTN AND IN COLLABORATION OF WRN/NRN NEIGHBORS BUT
SOME HIGHRES CONVN ALLOWING GUIDANCE DOES CAPTURE IL/ERN MO
DENSITY CURRENT THIS MORNING AND WOULD APPEAR TO MORE CORRECTLY
SUPPRESS CONVN HERE LOCALLY THIS AFTN/EVE WITHIN GENERALLY
SUBSIDENT/CAPPED AIRMASS.

OTRWS UPSTREAM CONVN XPCD TO INITIATE AND GROW UPSCALE THIS AFTN/EVE
VCNTY OF THE OZARK PLATUE AND LIFT NEWD IN REMNANT FASHION INTO AT
LEAST WRN AREAS LT TONIGHT AS LLJ FOCUSES INTO THE WRN LAKES.

&&

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 359 AM EDT MON MAY 20 2013

CONVECTION PLAGUING THE CENTRAL CONUS OVER THE PAST FEW NIGHTS WILL
FINALLY FULLY INFILTRATE THE SOUTHERN GREAT LAKES BY TUESDAY AS
CLOSED UPPER LOW SLOWLY MIGRATES EASTWARD. LACK OF ANY DISTINCT
SYNOPTIC FORCING WILL LEAD TO SEVERAL ROUNDS OF SHOWERS AND
THUNDERSTORMS SIMILAR TO WHAT HAS BEEN EXPERIENCED UPSTREAM. EXACT
TIMING AND LOCATION WILL DEPEND ON AMBIGUOUS MIDLEVEL WAVES ROTATING
THROUGH THE MEAN FLOW AND MESOSCALE SUBTLETIES DIFFICULT TO PINPOINT
THIS FAR OUT. ADDITIONALLY...HIGH THETA-E AIRMASS WILL BE FIRMLY IN
PLACE ACROSS THE REGION THANKS TO PERSISTENT SSW FLOW AND SURFACE
DEWPOINTS SHOULD BE HOVERING IN THE MID TO UPPER 60S. ATMOSPHERE
WILL BE LARGELY UNCAPPED BY TUESDAY AND THIS SHOULD SUPPORT MASS
CONVECTION IN WARM/HUMID AIRMASS. REASONABLY CONFIDENT IN PRECIP
OCCURRING AT SOME POINT TUESDAY BUT EXACT TIMING AND THE RESULTING
IMPACT ON BOTH HIGH TEMPS AND SEVERE CHANCES REMAINS NEBULOUS. WILL
LIKELY BE A FAIR AMOUNT OF NOCTURNAL CONVECTION CHURNING UPSTREAM
AND LATEST HI-RES GUIDANCE...AND EVEN THE COARSER NAM AND
GFS...SUGGEST THIS WILL MOVE OVER OUR AREA BY TUESDAY MORNING. THIS
WOULD SEVERELY LIMIT OUR DIURNAL INSTABILITY RECOVERY AND PREVENT US
FROM CAPITALIZING ON EXPECTED 30-40 KNOTS OF 0-6KM BULK SHEAR.
SEVERE WEATHER CHANCES WILL THEREFORE DEPEND ON FORTUITOUS BREAKS IN
CONVECTION THAT ALLOW INSTABILITY TO BUILD...WHICH MAY PROVE
DIFFICULT IN AN UNCAPPED ENVIRONMENT. SIMILARLY...HIGH TEMPS WILL BE
LARGELY DEPENDENT ON TIMING OF CONVECTION. THERMAL RIDGE WILL DAMPEN
EAST A BIT BY TUESDAY BUT 850MB TEMPS STILL LOOK TO BE AROUND 15C.
CERTAINLY WONT BE AS WARM AS TODAY BUT SHOULD STILL SQUEAK OUT MID
80S IN MOST PLACES...UPPER 80S IF ANY SUN PEAKS THROUGH.

AFTER ANOTHER VERY MILD NIGHT ON TUESDAY NIGHT...HIGHS ON WEDNESDAY
WILL LIKELY BE A CATEGORY COOLER AS AIRMASS BECOMES INCREASINGLY
HOMOGENEOUS AND ABUNDANT CLOUDS/PRECIP TEMPER DIURNAL RESPONSE.
ASSOCIATED WEAKENING OF LAPSE RATES ALOFT WILL FURTHER LIMIT OUR
SEVERE CHANCES BY WEDNESDAY. CAPE VALUES EXPECTED TO BE IN THE
500-1000 J/KG RANGE...ENOUGH FOR THUNDER MENTION BUT NO ORGANIZATION
EXPECTED. WIDESPREAD PRECIP STILL EXPECTED TO CONTINUE THOUGH WITH
SIMILAR SETUP TO THE PRIOR DAY. COULD SEE SOME LOCALLY HEAVY
RAINFALL TOTALS WHEN ALL IS SAID AND DONE GIVEN PW VALUES HOVERING
AROUND 1.5 INCHES FOR MUCH OF THE EVENT. WEAK SURFACE LOW AND
OCCLUDED FRONT WILL PASS THROUGH THE SOUTHERN GREAT LAKES BY LATE
WEDNESDAY AND WESTERLY FLOW WILL FINALLY ADVECT SOME DRIER AIR INTO
THE AREA. COULD STILL BE SOME SHOWERS ON THURSDAY AS THE OLD
MIDLEVEL VORT MAX ROTATES THROUGH BUT HEAVIER/WIDESPREAD PRECIP
SHOULD TAPER OFF WEDNESDAY NIGHT. TANGIBLE AIRMASS CHANGE WONT
ARRIVE UNTIL FRIDAY THOUGH WHEN 1030MB CANADIAN SURFACE HIGH SETTLES
OVER THE GREAT LAKES. EXPECT HIGHS ONLY IN THE MID TO UPPER 60S
FRI/SAT. LATTER HALF OF THE HOLIDAY WEEKEND CONTINUES TO BE A
STRUGGLE FOR VARIOUS DETERMINISTIC NWP WITH POTENTIAL INTRUSION OF
PRECIP ON BACKSIDE OF AFOREMENTIONED SURFACE HIGH. PLACEMENT OF
RELEVANT SYNOPTIC FEATURES AND RELATIVELY COLD LAKES FAVOR STRONGER
HIGH AND DRY FORECAST BUT THIS WILL CERTAINLY HAVE TO BE WATCHED AS
TIME GOES ON.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 128 PM EDT MON MAY 20 2013

VFR CONDITIONS EXPECTED FOR THE REST OF TODAY AND INTO
THE OVERNIGHT HOURS. SLIGHT CHANCE THAT A STRAY SHOWER OR ISOLATED
STORM COULD POP UP NEAR KFWA...BUT CONFIDENCE WAS TOO LOW FOR
INCLUSION IN 18Z TAF ISSUANCE. STORMS WILL FIRE ACROSS MISSOURI
TODAY AND WILL LIKELY TRACK INTO NORTHERN INDIANA DURING THE EARLY
MORNING HOURS. THIS THREAT IS GREATEST AT KSBN. WILL WAIT FOR LATER
TAF ISSUANCES BEFORE INCLUDING THESE STORMS AS SUBTLE TIMING
DIFFERENCES AND EXACT LOCATION WILL NOT BE KNOWN UNTIL THE
CONVECTION HAS FIRED AND BEGINS TRACKING TOWARDS THE AREA.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...STEINWEDEL
SHORT TERM...T
LONG TERM...AGD
AVIATION...BENTLEY


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIND 201646
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1246 PM EDT MON MAY 20 2013

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

&&

.SYNOPSIS...
ISSUED AT 300 AM EDT MON MAY 20 2013

A LARGE UPPER LOW CURRENTLY OVER THE PLAINS IS EXPECTED TO BRING
UNSETTLED WEATHER TO THE AREA THROUGH THURSDAY AS IT SLOWLY MOVES
EAST AND WEAKENS WITH TIME. HIGH PRESSURE IS EXPECTED TO BUILD IN
BEHIND THIS SYSTEM TOWARDS THE END OF THE WEEK. ANOTHER FRONTAL
SYSTEM MAY APPROACH THE AREA BY NEXT SUNDAY.

&&

.NEAR TERM /REST OF TODAY/...
ISSUED AT 1045 AM EDT MON MAY 20 2013

OUTFLOW BOUNDARY CURRENTLY MOVING INTO THE WESTERN BORDER ZONES
SEEMS TO BE LOSING ITS EASTWARD PUSH...BUT STILL QUITE A DEWPOINT
GRADIENT ALONG IT WITH DEWPOINTS FALLING INTO THE UPPER 50S BEHIND
BOUNDARY.

REMNANTS OF THIS BOUNDARY MAY MOVE FARTHER INTO THE AREA THIS
AFTERNOON AS IT WEAKENS. CONVECTION MAY DEVELOP ALONG THIS BOUNDARY
LATER THIS AFTERNOON AS AIR MASS IS EXPECTED TO BECOME VERY
UNSTABLE...HOWEVER A MID LEVEL CAP NOTED ON THIS MORNING/S UPPER AIR
MAY HELP SUPPRESS CONVECTION. MODEL DATA WEAKEN THIS CAP BY MID TO
LATE AFTERNOON...BUT SOME QUESTION AS TO WHETHER THIS WILL ACTUALLY
HAPPEN. WILL KEEP CHANCE POPS GOING FOR MAINLY LATER THIS AFTERNOON.
IF STORMS CAN BREAK THE CAP...LAPSE RATES QUITE FAVORABLE FOR
SEVERE...ALTHOUGH DEEP SHEAR CONTINUES TO LOOK RATHER WEAK.

QUITE A BIT OF CLOUD COVER HAS DEVELOPED OVER THE PAST COUPLE OF
HOURS...ALTHOUGH SATELLITE INDICATES SOME THINNING RECENTLY. AS A
RESULT...WILL LOWER THE HIGHS TODAY A COUPLE OF DEGREES.

PREVIOUS DISCUSSION FOLLOWS.

MODELS STILL HINTING AT A WEAK BOUNDARY ORIGINATING FROM CONVECTIVE
ACTIVITY TO THE WEST THAT WILL MOVE INTO THE AREA THIS AFTERNOON. AS
SO...THE AIR MASS WILL BECOME VERY UNSTABLE LATER TODAY WITH LIFTED
INDEXES AROUND -7/-8 AND STEEP LLVL LAPSE RATES. WILL CONTINUE TO
CARRY CHANCE POPS WITH THE HIGHEST AMOUNTS TO THE NORTH. VERY WARM
TEMPERATURES EXPECTED TODAY...AND ALONG WITH THE HIGHER DEW POINTS
WILL MAKE IT FEEL MUCH LIKE A MID SUMMER/S DAY. LEANED CLOSER TO THE
WARMER MET FOR HIGH IN THE UPPER 80S TO AROUND 90.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 300 AM EDT MON MAY 20 2013

MODELS PROGGING BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS...AND
POTENTIALLY SEVERE FOR TONIGHT...AS MUCH OF THE CWA IS IN A SLIGHT
RISK. BUMPED UP MUCH OF THE FORECAST AREA TO LIKELY BASED ON GOOD
MODEL CONSENSUS.

THE REST OF THE PERIOD LOOKS VERY UNSETTLED WITH ROUNDS OF
CONVECTION MAKING THE POSITION OF THE COLD FRONT HARD TO FIND.
HOWEVER IT APPEARS MODELS HAVE BUMPED UP THE TIMING OF THE MAIN COLD
FRONT TO WED...RATHER THAN WED NIGHT. HAVE LIKELY POPS IN FOR
WED...BUT BEFORE AND AFTER THAT CANNOT REALLY PIN DOWN ANY PERIODS
TO CONCENTRATE HIGH POPS ON...SO WILL CONTINUE TO BROADBRUSH HIGH
CHANCE POPS TUESDAY THRU TUE NIGHT AND AGAIN WED NIGHT.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
ISSUED AT 233 AM EDT MON MAY 20 2013

END OF AN ACTIVE WX PERIOD IS ANTICIPATED IN THE LONG TERM PORTION
OF THE FORECAST...AS LOW PRESSURE PULLS OUT OF THE AREA AND A
BROAD SURFACE RIDGE SETTLES INTO THE REGION DOWNSTREAM OF AN UPPER
RIDGE ACROSS THE CENTRAL PORTION OF THE COUNTRY. NOT OVERLY
PLEASED WITH ALLBLEND INITIALIZATION POPS BEYOND THURSDAY AS IT
WANTS TO INTRODUCE ANOTHER LENGTHY PERIOD OF SLIGHT CHANCE TO
CHANCE POPS OVER THE WEEKEND AND INTO NEXT WEEK...EVEN WITH THIS
SURFACE RIDGE ACROSS THE AREA AND LIMITED IF ANY UPPER LEVEL
SUPPORT FOR PRECIPITATION. HAVE GONE DRY FROM THURSDAY NIGHT ON.

ON TEMPS...EXPECTING NUMBERS CLOSER TO SEASONABLE LEVELS...IF NOT
SLIGHTLY BELOW AT TIMES THROUGHOUT THE PERIOD. IF DRY FORECAST
HOLDS...COULD MAKE FOR A VERY PLEASANT HOLIDAY WEEKEND ACROSS
CENTRAL INDIANA.

&&

.AVIATION /DISCUSSION FOR THE 201800Z TAFS/...

ISSUED AT 1237 PM EDT MON MAY 20 2013

VFR CONDITIONS ARE EXPECTED FOR MUCH OF THIS TAF PERIOD.

FORECAST SOUNDINGS ACROSS THE AREA INDICATE A DECENT MID LEVEL CAP
IN PLACE ACROSS THE AREA THAT SHOULD INHIBIT CONVECTION FOR
THE FIRST FEW HOURS OF THE TAF PERIOD. HOWEVER...CAPPING APPEARS TO
ERODE LATE IN THE AFTERNOON. THUS HAVE CONTINUED TO KEEP A
MENTION OF VCTS DUE TO DAYTIME HEATING IN THE VERY WARM AND
UNSTABLE AIR MASS THAT REMAINS IN PLACE ACROSS CENTRAL INDIANA.

ANY CONVECTIVE ACTIVITY SHOULD WAVE IN THE EVENING AS HEATING IS
LOST...HOWEVER GFS AND ECMWF SUGGEST CONVECTION WEST OF
INDIANA...OVER MISSOURI AND ILLINOIS MAY DRIFT INTO WESTERN PARTS
OF THE FORECAST AREA OVERNIGHT. AGAIN CONFIDENCE REMAINS LOW WITH
THESE FEATURES...SO FOR NOW JUST A VCTS MENTION.

GOOD MIXING OVERNIGHT SHOULD PREVENT MUCH IN THE WAY OF FOG FORMATION.

AS THAT WAVE DEPARTS ON TUESDAY MORNING...THE WARM AND UNSTABLE
AIR MASS WILL REMAIN IN PLACE ACROSS CENTRAL INDIANA AS YET
ANOTHER SHORT WAVE APPROACHES FROM THE WEST...PROVIDING MORE
SUPPORT FOR CONVECTION ON TUESDAY AFTERNOON AND TUESDAY NIGHT.

&&

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

$$

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

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

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

000
FXUS63 KIND 201454
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1050 AM EDT MON MAY 20 2013

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

&&

.SYNOPSIS...
ISSUED AT 300 AM EDT MON MAY 20 2013

A LARGE UPPER LOW CURRENTLY OVER THE PLAINS IS EXPECTED TO BRING
UNSETTLED WEATHER TO THE AREA THROUGH THURSDAY AS IT SLOWLY MOVES
EAST AND WEAKENS WITH TIME. HIGH PRESSURE IS EXPECTED TO BUILD IN
BEHIND THIS SYSTEM TOWARDS THE END OF THE WEEK. ANOTHER FRONTAL
SYSTEM MAY APPROACH THE AREA BY NEXT SUNDAY.

&&

.NEAR TERM /REST OF TODAY/...
ISSUED AT 1045 AM EDT MON MAY 20 2013

OUTFLOW BOUNDARY CURRENTLY MOVING INTO THE WESTERN BORDER ZONES
SEEMS TO BE LOSING ITS EASTWARD PUSH...BUT STILL QUITE A DEWPOINT
GRADIENT ALONG IT WITH DEWPOINTS FALLING INTO THE UPPER 50S BEHIND
BOUNDARY.

REMNANTS OF THIS BOUNDARY MAY MOVE FARTHER INTO THE AREA THIS
AFTERNOON AS IT WEAKENS. CONVECTION MAY DEVELOP ALONG THIS BOUNDARY
LATER THIS AFTERNOON AS AIR MASS IS EXPECTED TO BECOME VERY
UNSTABLE...HOWEVER A MID LEVEL CAP NOTED ON THIS MORNING/S UPPER AIR
MAY HELP SUPPRESS CONVECTION. MODEL DATA WEAKEN THIS CAP BY MID TO
LATE AFTERNOON...BUT SOME QUESTION AS TO WHETHER THIS WILL ACTUALLY
HAPPEN. WILL KEEP CHANCE POPS GOING FOR MAINLY LATER THIS AFTERNOON.
IF STORMS CAN BREAK THE CAP...LAPSE RATES QUITE FAVORABLE FOR
SEVERE...ALTHOUGH DEEP SHEAR CONTINUES TO LOOK RATHER WEAK.

QUITE A BIT OF CLOUD COVER HAS DEVELOPED OVER THE PAST COUPLE OF
HOURS...ALTHOUGH SATELLITE INDICATES SOME THINNING RECENTLY. AS A
RESULT...WILL LOWER THE HIGHS TODAY A COUPLE OF DEGREES.

PREVIOUS DISCUSSION FOLLOWS.

MODELS STILL HINTING AT A WEAK BOUNDARY ORIGINATING FROM CONVECTIVE
ACTIVITY TO THE WEST THAT WILL MOVE INTO THE AREA THIS AFTERNOON. AS
SO...THE AIR MASS WILL BECOME VERY UNSTABLE LATER TODAY WITH LIFTED
INDEXES AROUND -7/-8 AND STEEP LLVL LAPSE RATES. WILL CONTINUE TO
CARRY CHANCE POPS WITH THE HIGHEST AMOUNTS TO THE NORTH. VERY WARM
TEMPERATURES EXPECTED TODAY...AND ALONG WITH THE HIGHER DEW POINTS
WILL MAKE IT FEEL MUCH LIKE A MID SUMMER/S DAY. LEANED CLOSER TO THE
WARMER MET FOR HIGH IN THE UPPER 80S TO AROUND 90.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 300 AM EDT MON MAY 20 2013

MODELS PROGGING BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS...AND
POTENTIALLY SEVERE FOR TONIGHT...AS MUCH OF THE CWA IS IN A SLIGHT
RISK. BUMPED UP MUCH OF THE FORECAST AREA TO LIKELY BASED ON GOOD
MODEL CONSENSUS.

THE REST OF THE PERIOD LOOKS VERY UNSETTLED WITH ROUNDS OF
CONVECTION MAKING THE POSITION OF THE COLD FRONT HARD TO FIND.
HOWEVER IT APPEARS MODELS HAVE BUMPED UP THE TIMING OF THE MAIN COLD
FRONT TO WED...RATHER THAN WED NIGHT. HAVE LIKELY POPS IN FOR
WED...BUT BEFORE AND AFTER THAT CANNOT REALLY PIN DOWN ANY PERIODS
TO CONCENTRATE HIGH POPS ON...SO WILL CONTINUE TO BROADBRUSH HIGH
CHANCE POPS TUESDAY THRU TUE NIGHT AND AGAIN WED NIGHT.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
ISSUED AT 233 AM EDT MON MAY 20 2013

END OF AN ACTIVE WX PERIOD IS ANTICIPATED IN THE LONG TERM PORTION
OF THE FORECAST...AS LOW PRESSURE PULLS OUT OF THE AREA AND A
BROAD SURFACE RIDGE SETTLES INTO THE REGION DOWNSTREAM OF AN UPPER
RIDGE ACROSS THE CENTRAL PORTION OF THE COUNTRY. NOT OVERLY
PLEASED WITH ALLBLEND INITIALIZATION POPS BEYOND THURSDAY AS IT
WANTS TO INTRODUCE ANOTHER LENGTHY PERIOD OF SLIGHT CHANCE TO
CHANCE POPS OVER THE WEEKEND AND INTO NEXT WEEK...EVEN WITH THIS
SURFACE RIDGE ACROSS THE AREA AND LIMITED IF ANY UPPER LEVEL
SUPPORT FOR PRECIPITATION. HAVE GONE DRY FROM THURSDAY NIGHT ON.

ON TEMPS...EXPECTING NUMBERS CLOSER TO SEASONABLE LEVELS...IF NOT
SLIGHTLY BELOW AT TIMES THROUGHOUT THE PERIOD. IF DRY FORECAST
HOLDS...COULD MAKE FOR A VERY PLEASANT HOLIDAY WEEKEND ACROSS
CENTRAL INDIANA.

&&

.AVIATION /DISCUSSION FOR THE 201500Z IND TAF UPDATE/...

BRIEF MVFR CIGS ARE EXPECTED THE NEXT 1-2 HOURS.  OBSERVATIONAL TRENDS AND
SATELLITE SHOW BKN CU ACROSS SEVERAL OF THE TAF SITES. AS HEATING
CONTINUES CCL/S ARE EXPECTED TO RISE ABOVE 3000FT AND VFR CIGS
WILL BE THE RULE THIS AFTERNOON.

PLENTY OF CAPE AND INSTABILITY STILL APPEAR AVAILABLE THIS
AFTERNOON BASED UPON FORECAST SOUNDINGS. THUS FOR NOW THE ONGOING
VCTS SEEMS REASONABLE.

PREVIOUS DISCUSSION BELOW

/DISCUSSION FOR THE 20/12Z TAFS/...
ISSUED AT 713 AM EDT SUN MAY 19 2013

MVFR CONDITIONS AT SOME SITES EARLY IN THE PERIOD IN FOG AND STRATUS
WILL GIVE WAY TO VFR CONDITIONS LATER TODAY...OUTSIDE OF ANY
POTENTIAL SHOWERS AND THUNDERSTORMS.

WARM MOIST AIRMASS IN PLACE ACROSS THE AREA...PRIMED FOR POSSIBLE
SHOWERS AND STORMS LATER TODAY AND TONIGHT. UNCERTAINTIES IN TIMING
AND COVERAGE PRECLUDE EXPLICIT MENTIONS BEYOND VCTS/CB FROM MIDDAY
ON.

WINDS WILL GENERALLY BE OUT OF THE SOUTH AND WILL BECOME GUSTY
TODAY...INTO THE LOW TO MID 20KT RANGE. GUSTS WILL SUBSIDE THIS
EVENING BUT WINDS WILL REMAIN NEAR 8-10KT.


&&

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

$$

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

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

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

000
FXUS63 KIWX 201452
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1052 AM EDT MON MAY 20 2013

.SYNOPSIS...
ISSUED AT 1052 AM EDT MON MAY 20 2013

A SLOW MOVING LOW PRESSURE SYSTEM WILL BRING INCREASING CHANCES
FOR SHOWERS AND THUNDERSTORMS LATER TODAY THROUGH WEDNESDAY...WITH
A FEW SHOWERS POSSIBLY LINGERING INTO THURSDAY. THERE IS A SLIGHT
RISK FOR SEVERE THUNDERSTORMS THIS AFTERNOON THROUGH TUESDAY
NIGHT. DRIER AND COOLER WEATHER IS ANTICIPATED LATE THIS WEEK
INTO NEXT WEEKEND.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM EDT MON MAY 20 2013

DEEP REX BLOCKED CUTOFF LOW CNTRD OVR NRN NE THIS
MORNING WILL MOVE LTL THIS PD. THUS W/LTL CHG IN JET
STRUCTURE/POSITIONING ALOFT XPC CONVN WILL ONCE AGAIN STAY FOCUSED
WWD INVOF MS VALLEY.

LG SCALE GRAVITY WAVE EMINATING FM SLOWLY DECAYING CONVN ACRS WRN
IL SWWD INTO ERN MO WILL CONT EWD THIS MORNING. HWVR DOWNSTREAM
AIRMASS OF MUCH POORER QUALITY AS EVIDENT IN 00Z RAOBS AND
W/LLJ/MID LVL JET STREAK AXIS REMAINING ANCHORED TO THE WEST SEE
LTL EVIDENCE OF A SUFFICIENT SYNOPIC TRIGGER FOR AFTN CONVN AGAIN
TDA ESP IN LIGHT OF 00Z MODEL GUIDANCE SFC MSTR BIAS. WILL RETAIN
A LWR BOUND CHC MENTION NW HALF IN PROXIMITY TO EWD EDGE OF BTR LL
MASS FLUX THIS AFTN AND IN COLLABORATION OF WRN/NRN NEIGHBORS BUT
SOME HIGHRES CONVN ALLOWING GUIDANCE DOES CAPTURE IL/ERN MO
DENSITY CURRENT THIS MORNING AND WOULD APPEAR TO MORE CORRECTLY
SUPPRESS CONVN HERE LOCALLY THIS AFTN/EVE WITHIN GENERALLY
SUBSIDENT/CAPPED AIRMASS.

OTRWS UPSTREAM CONVN XPCD TO INITIATE AND GROW UPSCALE THIS AFTN/EVE
VCNTY OF THE OZARK PLATUE AND LIFT NEWD IN REMNANT FASHION INTO AT
LEAST WRN AREAS LT TONIGHT AS LLJ FOCUSES INTO THE WRN LAKES.

&&

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 359 AM EDT MON MAY 20 2013

CONVECTION PLAGUING THE CENTRAL CONUS OVER THE PAST FEW NIGHTS WILL
FINALLY FULLY INFILTRATE THE SOUTHERN GREAT LAKES BY TUESDAY AS
CLOSED UPPER LOW SLOWLY MIGRATES EASTWARD. LACK OF ANY DISTINCT
SYNOPTIC FORCING WILL LEAD TO SEVERAL ROUNDS OF SHOWERS AND
THUNDERSTORMS SIMILAR TO WHAT HAS BEEN EXPERIENCED UPSTREAM. EXACT
TIMING AND LOCATION WILL DEPEND ON AMBIGUOUS MIDLEVEL WAVES ROTATING
THROUGH THE MEAN FLOW AND MESOSCALE SUBTLETIES DIFFICULT TO PINPOINT
THIS FAR OUT. ADDITIONALLY...HIGH THETA-E AIRMASS WILL BE FIRMLY IN
PLACE ACROSS THE REGION THANKS TO PERSISTENT SSW FLOW AND SURFACE
DEWPOINTS SHOULD BE HOVERING IN THE MID TO UPPER 60S. ATMOSPHERE
WILL BE LARGELY UNCAPPED BY TUESDAY AND THIS SHOULD SUPPORT MASS
CONVECTION IN WARM/HUMID AIRMASS. REASONABLY CONFIDENT IN PRECIP
OCCURRING AT SOME POINT TUESDAY BUT EXACT TIMING AND THE RESULTING
IMPACT ON BOTH HIGH TEMPS AND SEVERE CHANCES REMAINS NEBULOUS. WILL
LIKELY BE A FAIR AMOUNT OF NOCTURNAL CONVECTION CHURNING UPSTREAM
AND LATEST HI-RES GUIDANCE...AND EVEN THE COARSER NAM AND
GFS...SUGGEST THIS WILL MOVE OVER OUR AREA BY TUESDAY MORNING. THIS
WOULD SEVERELY LIMIT OUR DIURNAL INSTABILITY RECOVERY AND PREVENT US
FROM CAPITALIZING ON EXPECTED 30-40 KNOTS OF 0-6KM BULK SHEAR.
SEVERE WEATHER CHANCES WILL THEREFORE DEPEND ON FORTUITOUS BREAKS IN
CONVECTION THAT ALLOW INSTABILITY TO BUILD...WHICH MAY PROVE
DIFFICULT IN AN UNCAPPED ENVIRONMENT. SIMILARLY...HIGH TEMPS WILL BE
LARGELY DEPENDENT ON TIMING OF CONVECTION. THERMAL RIDGE WILL DAMPEN
EAST A BIT BY TUESDAY BUT 850MB TEMPS STILL LOOK TO BE AROUND 15C.
CERTAINLY WONT BE AS WARM AS TODAY BUT SHOULD STILL SQUEAK OUT MID
80S IN MOST PLACES...UPPER 80S IF ANY SUN PEAKS THROUGH.

AFTER ANOTHER VERY MILD NIGHT ON TUESDAY NIGHT...HIGHS ON WEDNESDAY
WILL LIKELY BE A CATEGORY COOLER AS AIRMASS BECOMES INCREASINGLY
HOMOGENEOUS AND ABUNDANT CLOUDS/PRECIP TEMPER DIURNAL RESPONSE.
ASSOCIATED WEAKENING OF LAPSE RATES ALOFT WILL FURTHER LIMIT OUR
SEVERE CHANCES BY WEDNESDAY. CAPE VALUES EXPECTED TO BE IN THE
500-1000 J/KG RANGE...ENOUGH FOR THUNDER MENTION BUT NO ORGANIZATION
EXPECTED. WIDESPREAD PRECIP STILL EXPECTED TO CONTINUE THOUGH WITH
SIMILAR SETUP TO THE PRIOR DAY. COULD SEE SOME LOCALLY HEAVY
RAINFALL TOTALS WHEN ALL IS SAID AND DONE GIVEN PW VALUES HOVERING
AROUND 1.5 INCHES FOR MUCH OF THE EVENT. WEAK SURFACE LOW AND
OCCLUDED FRONT WILL PASS THROUGH THE SOUTHERN GREAT LAKES BY LATE
WEDNESDAY AND WESTERLY FLOW WILL FINALLY ADVECT SOME DRIER AIR INTO
THE AREA. COULD STILL BE SOME SHOWERS ON THURSDAY AS THE OLD
MIDLEVEL VORT MAX ROTATES THROUGH BUT HEAVIER/WIDESPREAD PRECIP
SHOULD TAPER OFF WEDNESDAY NIGHT. TANGIBLE AIRMASS CHANGE WONT
ARRIVE UNTIL FRIDAY THOUGH WHEN 1030MB CANADIAN SURFACE HIGH SETTLES
OVER THE GREAT LAKES. EXPECT HIGHS ONLY IN THE MID TO UPPER 60S
FRI/SAT. LATTER HALF OF THE HOLIDAY WEEKEND CONTINUES TO BE A
STRUGGLE FOR VARIOUS DETERMINISTIC NWP WITH POTENTIAL INTRUSION OF
PRECIP ON BACKSIDE OF AFOREMENTIONED SURFACE HIGH. PLACEMENT OF
RELEVANT SYNOPTIC FEATURES AND RELATIVELY COLD LAKES FAVOR STRONGER
HIGH AND DRY FORECAST BUT THIS WILL CERTAINLY HAVE TO BE WATCHED AS
TIME GOES ON.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 359 AM EDT MON MAY 20 2013

VFR CONDS THROUGH THE PD. CLOSED LOW VCNTY OF SD WILL
MOVE LTL THIS PD. THUS W/LTL CHG ALOFT SUSPECT CONVN WILL REMAIN
WELL WEST OF TERMINALS WITHIN FOCUSED/COLLOCATED STGR SWRLY FLW AND
GREATER INSTABILITY PLUME. HWVR UPSTREAM CONVN XPCD TO SPARK AGAIN
THIS AFTN VCNTY OF THE OZARKS AND LIFT NEWD INTO THE WRN LAKES LT
TONIGHT W/INCREASING COND PROBABILITY TO AFFECT KSBN TERMINAL TWD
12Z.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...STEINWEDEL
SHORT TERM...T
LONG TERM...AGD
AVIATION...T


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIND 201433
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1033 AM EDT MON MAY 20 2013

.UPDATE...
AVIATION SECTION UPDATED

&&

.SYNOPSIS...
ISSUED AT 300 AM EDT MON MAY 20 2013

A LARGE UPPER LOW CURRENTLY OVER THE PLAINS IS EXPECTED TO BRING
UNSETTLED WEATHER TO THE AREA THROUGH THURSDAY AS IT SLOWLY MOVES
EAST AND WEAKENS WITH TIME. HIGH PRESSURE IS EXPECTED TO BUILD IN
BEHIND THIS SYSTEM TOWARDS THE END OF THE WEEK. ANOTHER FRONTAL
SYSTEM MAY APPROACH THE AREA BY NEXT SUNDAY.

&&

.NEAR TERM /TODAY/...
ISSUED AT 300 AM EDT MON MAY 20 2013

MODELS STILL HINTING AT A WEAK BOUNDARY ORIGINATING FROM CONVECTIVE
ACTIVITY TO THE WEST THAT WILL MOVE INTO THE AREA THIS AFTERNOON. AS
SO...THE AIR MASS WILL BECOME VERY UNSTABLE LATER TODAY WITH LIFTED
INDEXES AROUND -7/-8 AND STEEP LLVL LAPSE RATES. WILL CONTINUE TO
CARRY CHANCE POPS WITH THE HIGHEST AMOUNTS TO THE NORTH. VERY WARM
TEMPERATURES EXPECTED TODAY...AND ALONG WITH THE HIGHER DEW POINTS
WILL MAKE IT FEEL MUCH LIKE A MID SUMMER/S DAY. LEANED CLOSER TO THE
WARMER MET FOR HIGH IN THE UPPER 80S TO AROUND 90.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 300 AM EDT MON MAY 20 2013

MODELS PROGGING BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS...AND
POTENTIALLY SEVERE FOR TONIGHT...AS MUCH OF THE CWA IS IN A SLIGHT
RISK. BUMPED UP MUCH OF THE FORECAST AREA TO LIKELY BASED ON GOOD
MODEL CONSENSUS.

THE REST OF THE PERIOD LOOKS VERY UNSETTLED WITH ROUNDS OF
CONVECTION MAKING THE POSITION OF THE COLD FRONT HARD TO FIND.
HOWEVER IT APPEARS MODELS HAVE BUMPED UP THE TIMING OF THE MAIN COLD
FRONT TO WED...RATHER THAN WED NIGHT. HAVE LIKELY POPS IN FOR
WED...BUT BEFORE AND AFTER THAT CANNOT REALLY PIN DOWN ANY PERIODS
TO CONCENTRATE HIGH POPS ON...SO WILL CONTINUE TO BROADBRUSH HIGH
CHANCE POPS TUESDAY THRU TUE NIGHT AND AGAIN WED NIGHT.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
ISSUED AT 233 AM EDT MON MAY 20 2013

END OF AN ACTIVE WX PERIOD IS ANTICIPATED IN THE LONG TERM PORTION
OF THE FORECAST...AS LOW PRESSURE PULLS OUT OF THE AREA AND A
BROAD SURFACE RIDGE SETTLES INTO THE REGION DOWNSTREAM OF AN UPPER
RIDGE ACROSS THE CENTRAL PORTION OF THE COUNTRY. NOT OVERLY
PLEASED WITH ALLBLEND INITIALIZATION POPS BEYOND THURSDAY AS IT
WANTS TO INTRODUCE ANOTHER LENGTHY PERIOD OF SLIGHT CHANCE TO
CHANCE POPS OVER THE WEEKEND AND INTO NEXT WEEK...EVEN WITH THIS
SURFACE RIDGE ACROSS THE AREA AND LIMITED IF ANY UPPER LEVEL
SUPPORT FOR PRECIPITATION. HAVE GONE DRY FROM THURSDAY NIGHT ON.

ON TEMPS...EXPECTING NUMBERS CLOSER TO SEASONABLE LEVELS...IF NOT
SLIGHTLY BELOW AT TIMES THROUGHOUT THE PERIOD. IF DRY FORECAST
HOLDS...COULD MAKE FOR A VERY PLEASANT HOLIDAY WEEKEND ACROSS
CENTRAL INDIANA.

&&

.AVIATION /DISCUSSION FOR THE 201500Z IND TAF UPDATE/...

BRIEF MVFR CIGS ARE EXPECTED THE NEXT 1-2 HOURS.  OBSERVATIONAL TRENDS AND
SATELLITE SHOW BKN CU ACROSS SEVERAL OF THE TAF SITES. AS HEATING
CONTINUES CCL/S ARE EXPECTED TO RISE ABOVE 3000FT AND VFR CIGS
WILL BE THE RULE THIS AFTERNOON.

PLENTY OF CAPE AND INSTABILITY STILL APPEAR AVAILABLE THIS
AFTERNOON BASED UPON FORECAST SOUNDINGS. THUS FOR NOW THE ONGOING
VCTS SEEMS REASONABLE.

PREVIOUS DISCUSSION BELOW

/DISCUSSION FOR THE 20/12Z TAFS/...
ISSUED AT 713 AM EDT SUN MAY 19 2013

MVFR CONDITIONS AT SOME SITES EARLY IN THE PERIOD IN FOG AND STRATUS
WILL GIVE WAY TO VFR CONDITIONS LATER TODAY...OUTSIDE OF ANY
POTENTIAL SHOWERS AND THUNDERSTORMS.

WARM MOIST AIRMASS IN PLACE ACROSS THE AREA...PRIMED FOR POSSIBLE
SHOWERS AND STORMS LATER TODAY AND TONIGHT. UNCERTAINTIES IN TIMING
AND COVERAGE PRECLUDE EXPLICIT MENTIONS BEYOND VCTS/CB FROM MIDDAY
ON.

WINDS WILL GENERALLY BE OUT OF THE SOUTH AND WILL BECOME GUSTY
TODAY...INTO THE LOW TO MID 20KT RANGE. GUSTS WILL SUBSIDE THIS
EVENING BUT WINDS WILL REMAIN NEAR 8-10KT.


&&

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

$$

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

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

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

000
FXUS63 KIND 201113
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
713 AM EDT MON MAY 20 2013

.UPDATE...

THE AVIATION SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 300 AM EDT MON MAY 20 2013

A LARGE UPPER LOW CURRENTLY OVER THE PLAINS IS EXPECTED TO BRING
UNSETTLED WEATHER TO THE AREA THROUGH THURSDAY AS IT SLOWLY MOVES
EAST AND WEAKENS WITH TIME. HIGH PRESSURE IS EXPECTED TO BUILD IN
BEHIND THIS SYSTEM TOWARDS THE END OF THE WEEK. ANOTHER FRONTAL
SYSTEM MAY APPROACH THE AREA BY NEXT SUNDAY.

&&

.NEAR TERM /TODAY/...
ISSUED AT 300 AM EDT MON MAY 20 2013

MODELS STILL HINTING AT A WEAK BOUNDARY ORIGINATING FROM CONVECTIVE
ACTIVITY TO THE WEST THAT WILL MOVE INTO THE AREA THIS AFTERNOON. AS
SO...THE AIR MASS WILL BECOME VERY UNSTABLE LATER TODAY WITH LIFTED
INDEXES AROUND -7/-8 AND STEEP LLVL LAPSE RATES. WILL CONTINUE TO
CARRY CHANCE POPS WITH THE HIGHEST AMOUNTS TO THE NORTH. VERY WARM
TEMPERATURES EXPECTED TODAY...AND ALONG WITH THE HIGHER DEW POINTS
WILL MAKE IT FEEL MUCH LIKE A MID SUMMER/S DAY. LEANED CLOSER TO THE
WARMER MET FOR HIGH IN THE UPPER 80S TO AROUND 90.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 300 AM EDT MON MAY 20 2013

MODELS PROGGING BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS...AND
POTENTIALLY SEVERE FOR TONIGHT...AS MUCH OF THE CWA IS IN A SLIGHT
RISK. BUMPED UP MUCH OF THE FORECAST AREA TO LIKELY BASED ON GOOD
MODEL CONSENSUS.

THE REST OF THE PERIOD LOOKS VERY UNSETTLED WITH ROUNDS OF
CONVECTION MAKING THE POSITION OF THE COLD FRONT HARD TO FIND.
HOWEVER IT APPEARS MODELS HAVE BUMPED UP THE TIMING OF THE MAIN COLD
FRONT TO WED...RATHER THAN WED NIGHT. HAVE LIKELY POPS IN FOR
WED...BUT BEFORE AND AFTER THAT CANNOT REALLY PIN DOWN ANY PERIODS
TO CONCENTRATE HIGH POPS ON...SO WILL CONTINUE TO BROADBRUSH HIGH
CHANCE POPS TUESDAY THRU TUE NIGHT AND AGAIN WED NIGHT.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
ISSUED AT 233 AM EDT MON MAY 20 2013

END OF AN ACTIVE WX PERIOD IS ANTICIPATED IN THE LONG TERM PORTION
OF THE FORECAST...AS LOW PRESSURE PULLS OUT OF THE AREA AND A
BROAD SURFACE RIDGE SETTLES INTO THE REGION DOWNSTREAM OF AN UPPER
RIDGE ACROSS THE CENTRAL PORTION OF THE COUNTRY. NOT OVERLY
PLEASED WITH ALLBLEND INITIALIZATION POPS BEYOND THURSDAY AS IT
WANTS TO INTRODUCE ANOTHER LENGTHY PERIOD OF SLIGHT CHANCE TO
CHANCE POPS OVER THE WEEKEND AND INTO NEXT WEEK...EVEN WITH THIS
SURFACE RIDGE ACROSS THE AREA AND LIMITED IF ANY UPPER LEVEL
SUPPORT FOR PRECIPITATION. HAVE GONE DRY FROM THURSDAY NIGHT ON.

ON TEMPS...EXPECTING NUMBERS CLOSER TO SEASONABLE LEVELS...IF NOT
SLIGHTLY BELOW AT TIMES THROUGHOUT THE PERIOD. IF DRY FORECAST
HOLDS...COULD MAKE FOR A VERY PLEASANT HOLIDAY WEEKEND ACROSS
CENTRAL INDIANA.

&&

.AVIATION /DISCUSSION FOR THE 20/12Z TAFS/...
ISSUED AT 713 AM EDT SUN MAY 19 2013

MVFR CONDITIONS AT SOME SITES EARLY IN THE PERIOD IN FOG AND STRATUS
WILL GIVE WAY TO VFR CONDITIONS LATER TODAY...OUTSIDE OF ANY
POTENTIAL SHOWERS AND THUNDERSTORMS.

WARM MOIST AIRMASS IN PLACE ACROSS THE AREA...PRIMED FOR POSSIBLE
SHOWERS AND STORMS LATER TODAY AND TONIGHT. UNCERTAINTIES IN TIMING
AND COVERAGE PRECLUDE EXPLICIT MENTIONS BEYOND VCTS/CB FROM MIDDAY
ON.

WINDS WILL GENERALLY BE OUT OF THE SOUTH AND WILL BECOME GUSTY
TODAY...INTO THE LOW TO MID 20KT RANGE. GUSTS WILL SUBSIDE THIS
EVENING BUT WINDS WILL REMAIN NEAR 8-10KT.

&&

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

&&

$$

SYNOPSIS...SMF
NEAR TERM...SMF
SHORT TERM...SMF
LONG TERM....NIELD
AVIATION...NIELD

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

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

000
FXUS63 KIND 200810
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
410 AM EDT MON MAY 20 2013

.UPDATE...

THE AVIATION SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 300 AM EDT MON MAY 20 2013

A LARGE UPPER LOW CURRENTLY OVER THE PLAINS IS EXPECTED TO BRING
UNSETTLED WEATHER TO THE AREA THROUGH THURSDAY AS IT SLOWLY MOVES
EAST AND WEAKENS WITH TIME. HIGH PRESSURE IS EXPECTED TO BUILD IN
BEHIND THIS SYSTEM TOWARDS THE END OF THE WEEK. ANOTHER FRONTAL
SYSTEM MAY APPROACH THE AREA BY NEXT SUNDAY.

&&

.NEAR TERM /TODAY/...
ISSUED AT 300 AM EDT MON MAY 20 2013

MODELS STILL HINTING AT A WEAK BOUNDARY ORIGINATING FROM CONVECTIVE
ACTIVITY TO THE WEST THAT WILL MOVE INTO THE AREA THIS AFTERNOON. AS
SO...THE AIR MASS WILL BECOME VERY UNSTABLE LATER TODAY WITH LIFTED
INDEXES AROUND -7/-8 AND STEEP LLVL LAPSE RATES. WILL CONTINUE TO
CARRY CHANCE POPS WITH THE HIGHEST AMOUNTS TO THE NORTH. VERY WARM
TEMPERATURES EXPECTED TODAY...AND ALONG WITH THE HIGHER DEW POINTS
WILL MAKE IT FEEL MUCH LIKE A MID SUMMER/S DAY. LEANED CLOSER TO THE
WARMER MET FOR HIGH IN THE UPPER 80S TO AROUND 90.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 300 AM EDT MON MAY 20 2013

MODELS PROGGING BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS...AND
POTENTIALLY SEVERE FOR TONIGHT...AS MUCH OF THE CWA IS IN A SLIGHT
RISK. BUMPED UP MUCH OF THE FORECAST AREA TO LIKELY BASED ON GOOD
MODEL CONSENSUS.

THE REST OF THE PERIOD LOOKS VERY UNSETTLED WITH ROUNDS OF
CONVECTION MAKING THE POSITION OF THE COLD FRONT HARD TO FIND.
HOWEVER IT APPEARS MODELS HAVE BUMPED UP THE TIMING OF THE MAIN COLD
FRONT TO WED...RATHER THAN WED NIGHT. HAVE LIKELY POPS IN FOR
WED...BUT BEFORE AND AFTER THAT CANNOT REALLY PIN DOWN ANY PERIODS
TO CONCENTRATE HIGH POPS ON...SO WILL CONTINUE TO BROADBRUSH HIGH
CHANCE POPS TUESDAY THRU TUE NIGHT AND AGAIN WED NIGHT.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
ISSUED AT 233 AM EDT MON MAY 20 2013

END OF AN ACTIVE WX PERIOD IS ANTICIPATED IN THE LONG TERM PORTION
OF THE FORECAST...AS LOW PRESSURE PULLS OUT OF THE AREA AND A
BROAD SURFACE RIDGE SETTLES INTO THE REGION DOWNSTREAM OF AN UPPER
RIDGE ACROSS THE CENTRAL PORTION OF THE COUNTRY. NOT OVERLY
PLEASED WITH ALLBLEND INITIALIZATION POPS BEYOND THURSDAY AS IT
WANTS TO INTRODUCE ANOTHER LENGTHY PERIOD OF SLIGHT CHANCE TO
CHANCE POPS OVER THE WEEKEND AND INTO NEXT WEEK...EVEN WITH THIS
SURFACE RIDGE ACROSS THE AREA AND LIMITED IF ANY UPPER LEVEL
SUPPORT FOR PRECIPITATION. HAVE GONE DRY FROM THURSDAY NIGHT ON.

ON TEMPS...EXPECTING NUMBERS CLOSER TO SEASONABLE LEVELS...IF NOT
SLIGHTLY BELOW AT TIMES THROUGHOUT THE PERIOD. IF DRY FORECAST
HOLDS...COULD MAKE FOR A VERY PLEASANT HOLIDAY WEEKEND ACROSS
CENTRAL INDIANA.

&&

.AVIATION /DISCUSSION FOR THE 20/09Z TAF UPDATE/...
ISSUED AT 410 AM EDT SUN MAY 19 2013

MVFR FOG HAS DEVELOPED AT BMG AND MAY DEVELOP ON A TEMPORARY BASIS
AT OTHER SITES. CANNOT RULE OUT PERIODS OF IFR AT BMG. AMENDMENTS
REFLECT THIS EXPECTATION THROUGH DAYBREAK. PREVIOUS DISCUSSION
FOLLOWS.

ISSUED AT 1244 AM EDT SUN MAY 19 2013

VFR CONDITIONS EXPECTED DURING THE TAF PERIOD...EXCEPT HUF AND EVEN
MORE SO BMG COULD SEE SOME RESTRICTIONS TO VISIBILITY AFTER 08Z AS
DEW POINTS WERE IN THE UPPER 60S AND LOWER 70S THERE LATE THIS
EVENING AND WINDS WERE ONLY 3 KNOTS AT BMG. WOULD ALSO NOT RULE OUT
SOME LOW STRATUS AS MODEL TIME SECTIONS WERE SHOWING PLENTY OF LOW
LEVEL MOISTURE. WILL GO WITH SCATTERED CLOUDS BELOW 1000 FEET
OVERNIGHT AND MVFR FOG AT HUF AFTER 08Z AND MVFR AND TEMPO IFR AT
BMG. THE OTHER SITES SHOULD NOT SEE ANY FOG WITH WINDS REMAINING 5
KNOTS OR MORE AND WITH DEW POINTS A TAD LOWER IN THE MID 60S.

COULD SEE SOME THUNDERSTORMS AFTER DAYBREAK ESPECIALLY DURING THE
AFTERNOON...BUT WITH COVERAGE EXPECTED TO BE SCATTERED AT BEST AND
BEING SO FAR OUT...WILL HOLD OFF ON VCTS UNTIL AFTER 00Z TUESDAY
AS COVERAGE SHOULD BE A LITTLE BETTER THEN. SHOULD SEE SCATTERED TO
BROKEN DIURNAL VFR CU TOMORROW AFTERNOON. WINDS WILL BE INCREASING
TOMORROW WITH SOUTH AND SOUTHWEST WINDS INCREASING TO AROUND 15
KNOTS WITH GUSTS TO 23 KNOTS AFTER 14Z.

&&

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

&&

$$

SYNOPSIS...SMF
NEAR TERM...SMF
SHORT TERM...SMF
LONG TERM....NIELD
AVIATION...MK/NIELD

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

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

000
FXUS63 KIWX 200801
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
401 AM EDT MON MAY 20 2013

.SYNOPSIS...
ISSUED AT 400 AM EDT MON MAY 20 2013

SKIES WILL BE PARTLY CLOUDY TODAY...WITH HIGH TEMPERATURES OF 85
TO 90. A LOW PRESSURE SYSTEM WILL MAKE ITS WAY ACROSS THE REGION
THROUGH MID WEEK...BRINGING CHANCES FOR SHOWERS AND THUNDERSTORMS.
TEMPERATURES ARE EXPECTED TO CONTINUE WELL ABOVE NORMAL TODAY AND
TUESDAY BEFORE DROPPING DOWN TO MORE SEASONABLE LEVELS THURSDAY
THROUGH THE WEEKEND.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM EDT MON MAY 20 2013

DEEP REX BLOCKED CUTOFF LOW CNTRD OVR NRN NE THIS
MORNING WILL MOVE LTL THIS PD. THUS W/LTL CHG IN JET
STRUCTURE/POSITIONING ALOFT XPC CONVN WILL ONCE AGAIN STAY FOCUSED
WWD INVOF MS VALLEY.

LG SCALE GRAVITY WAVE EMINATING FM SLOWLY DECAYING CONVN ACRS WRN
IL SWWD INTO ERN MO WILL CONT EWD THIS MORNING. HWVR DOWNSTREAM
AIRMASS OF MUCH POORER QUALITY AS EVIDENT IN 00Z RAOBS AND
W/LLJ/MID LVL JET STREAK AXIS REMAINING ANCHORED TO THE WEST SEE
LTL EVIDENCE OF A SUFFICIENT SYNOPIC TRIGGER FOR AFTN CONVN AGAIN
TDA ESP IN LIGHT OF 00Z MODEL GUIDANCE SFC MSTR BIAS. WILL RETAIN
A LWR BOUND CHC MENTION NW HALF IN PROXIMITY TO EWD EDGE OF BTR LL
MASS FLUX THIS AFTN AND IN COLLABORATION OF WRN/NRN NEIGHBORS BUT
SOME HIGHRES CONVN ALLOWING GUIDANCE DOES CAPTURE IL/ERN MO
DENSITY CURRENT THIS MORNING AND WOULD APPEAR TO MORE CORRECTLY
SUPPRESS CONVN HERE LOCALLY THIS AFTN/EVE WITHIN GENERALLY
SUBSIDENT/CAPPED AIRMASS.

OTRWS UPSTREAM CONVN XPCD TO INITIATE AND GROW UPSCALE THIS AFTN/EVE
VCNTY OF THE OZARK PLATUE AND LIFT NEWD IN REMNANT FASHION INTO AT
LEAST WRN AREAS LT TONIGHT AS LLJ FOCUSES INTO THE WRN LAKES.

&&

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 359 AM EDT MON MAY 20 2013

CONVECTION PLAGUING THE CENTRAL CONUS OVER THE PAST FEW NIGHTS WILL
FINALLY FULLY INFILTRATE THE SOUTHERN GREAT LAKES BY TUESDAY AS
CLOSED UPPER LOW SLOWLY MIGRATES EASTWARD. LACK OF ANY DISTINCT
SYNOPTIC FORCING WILL LEAD TO SEVERAL ROUNDS OF SHOWERS AND
THUNDERSTORMS SIMILAR TO WHAT HAS BEEN EXPERIENCED UPSTREAM. EXACT
TIMING AND LOCATION WILL DEPEND ON AMBIGUOUS MIDLEVEL WAVES ROTATING
THROUGH THE MEAN FLOW AND MESOSCALE SUBTLETIES DIFFICULT TO PINPOINT
THIS FAR OUT. ADDITIONALLY...HIGH THETA-E AIRMASS WILL BE FIRMLY IN
PLACE ACROSS THE REGION THANKS TO PERSISTENT SSW FLOW AND SURFACE
DEWPOINTS SHOULD BE HOVERING IN THE MID TO UPPER 60S. ATMOSPHERE
WILL BE LARGELY UNCAPPED BY TUESDAY AND THIS SHOULD SUPPORT MASS
CONVECTION IN WARM/HUMID AIRMASS. REASONABLY CONFIDENT IN PRECIP
OCCURRING AT SOME POINT TUESDAY BUT EXACT TIMING AND THE RESULTING
IMPACT ON BOTH HIGH TEMPS AND SEVERE CHANCES REMAINS NEBULOUS. WILL
LIKELY BE A FAIR AMOUNT OF NOCTURNAL CONVECTION CHURNING UPSTREAM
AND LATEST HI-RES GUIDANCE...AND EVEN THE COARSER NAM AND
GFS...SUGGEST THIS WILL MOVE OVER OUR AREA BY TUESDAY MORNING. THIS
WOULD SEVERELY LIMIT OUR DIURNAL INSTABILITY RECOVERY AND PREVENT US
FROM CAPITALIZING ON EXPECTED 30-40 KNOTS OF 0-6KM BULK SHEAR.
SEVERE WEATHER CHANCES WILL THEREFORE DEPEND ON FORTUITOUS BREAKS IN
CONVECTION THAT ALLOW INSTABILITY TO BUILD...WHICH MAY PROVE
DIFFICULT IN AN UNCAPPED ENVIRONMENT. SIMILARLY...HIGH TEMPS WILL BE
LARGELY DEPENDENT ON TIMING OF CONVECTION. THERMAL RIDGE WILL DAMPEN
EAST A BIT BY TUESDAY BUT 850MB TEMPS STILL LOOK TO BE AROUND 15C.
CERTAINLY WONT BE AS WARM AS TODAY BUT SHOULD STILL SQUEAK OUT MID
80S IN MOST PLACES...UPPER 80S IF ANY SUN PEAKS THROUGH.

AFTER ANOTHER VERY MILD NIGHT ON TUESDAY NIGHT...HIGHS ON WEDNESDAY
WILL LIKELY BE A CATEGORY COOLER AS AIRMASS BECOMES INCREASINGLY
HOMOGENEOUS AND ABUNDANT CLOUDS/PRECIP TEMPER DIURNAL RESPONSE.
ASSOCIATED WEAKENING OF LAPSE RATES ALOFT WILL FURTHER LIMIT OUR
SEVERE CHANCES BY WEDNESDAY. CAPE VALUES EXPECTED TO BE IN THE
500-1000 J/KG RANGE...ENOUGH FOR THUNDER MENTION BUT NO ORGANIZATION
EXPECTED. WIDESPREAD PRECIP STILL EXPECTED TO CONTINUE THOUGH WITH
SIMILAR SETUP TO THE PRIOR DAY. COULD SEE SOME LOCALLY HEAVY
RAINFALL TOTALS WHEN ALL IS SAID AND DONE GIVEN PW VALUES HOVERING
AROUND 1.5 INCHES FOR MUCH OF THE EVENT. WEAK SURFACE LOW AND
OCCLUDED FRONT WILL PASS THROUGH THE SOUTHERN GREAT LAKES BY LATE
WEDNESDAY AND WESTERLY FLOW WILL FINALLY ADVECT SOME DRIER AIR INTO
THE AREA. COULD STILL BE SOME SHOWERS ON THURSDAY AS THE OLD
MIDLEVEL VORT MAX ROTATES THROUGH BUT HEAVIER/WIDESPREAD PRECIP
SHOULD TAPER OFF WEDNESDAY NIGHT. TANGIBLE AIRMASS CHANGE WONT
ARRIVE UNTIL FRIDAY THOUGH WHEN 1030MB CANADIAN SURFACE HIGH SETTLES
OVER THE GREAT LAKES. EXPECT HIGHS ONLY IN THE MID TO UPPER 60S
FRI/SAT. LATTER HALF OF THE HOLIDAY WEEKEND CONTINUES TO BE A
STRUGGLE FOR VARIOUS DETERMINISTIC NWP WITH POTENTIAL INTRUSION OF
PRECIP ON BACKSIDE OF AFOREMENTIONED SURFACE HIGH. PLACEMENT OF
RELEVANT SYNOPTIC FEATURES AND RELATIVELY COLD LAKES FAVOR STRONGER
HIGH AND DRY FORECAST BUT THIS WILL CERTAINLY HAVE TO BE WATCHED AS
TIME GOES ON.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 359 AM EDT MON MAY 20 2013

VFR CONDS THROUGH THE PD. CLOSED LOW VCNTY OF SD WILL
MOVE LTL THIS PD. THUS W/LTL CHG ALOFT SUSPECT CONVN WILL REMAIN
WELL WEST OF TERMINALS WITHIN FOCUSED/COLLOCATED STGR SWRLY FLW AND
GREATER INSTABILITY PLUME. HWVR UPSTREAM CONVN XPCD TO SPARK AGAIN
THIS AFTN VCNTY OF THE OZARKS AND LIFT NEWD INTO THE WRN LAKES LT
TONIGHT W/INCREASING COND PROBABILITY TO AFFECT KSBN TERMINAL TWD
12Z.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...KG
SHORT TERM...T
LONG TERM...AGD
AVIATION...T


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIND 200702
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
302 AM EDT MON MAY 20 2013

.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED
BELOW.

&&

.SYNOPSIS...

ISSUED AT 300 AM EDT MON MAY 20 2013

A LARGE UPPER LOW CURRENTLY OVER THE PLAINS IS EXPECTED TO BRING
UNSETTLED WEATHER TO THE AREA THROUGH THURSDAY AS IT SLOWLY MOVES
EAST AND WEAKENS WITH TIME. HIGH PRESSURE IS EXPECTED TO BUILD IN
BEHIND THIS SYSTEM TOWARDS THE END OF THE WEEK. ANOTHER FRONTAL
SYSTEM MAY APPROACH THE AREA BY NEXT SUNDAY.

&&

.NEAR TERM /TODAY/...

ISSUED AT 300 AM EDT MON MAY 20 2013

MODELS STILL HINTING AT A WEAK BOUNDARY ORIGINATING FROM CONVECTIVE
ACTIVITY TO THE WEST THAT WILL MOVE INTO THE AREA THIS AFTERNOON. AS
SO...THE AIR MASS WILL BECOME VERY UNSTABLE LATER TODAY WITH LIFTED
INDEXES AROUND -7/-8 AND STEEP LLVL LAPSE RATES. WILL CONTINUE TO
CARRY CHANCE POPS WITH THE HIGHEST AMOUNTS TO THE NORTH. VERY WARM
TEMPERATURES EXPECTED TODAY...AND ALONG WITH THE HIGHER DEW POINTS
WILL MAKE IT FEEL MUCH LIKE A MID SUMMER/S DAY. LEANED CLOSER TO THE
WARMER MET FOR HIGH IN THE UPPER 80S TO AROUND 90.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...

ISSUED AT 300 AM EDT MON MAY 20 2013

MODELS PROGGING BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS...AND
POTENTIALLY SEVERE FOR TONIGHT...AS MUCH OF THE CWA IS IN A SLIGHT
RISK. BUMPED UP MUCH OF THE FORECAST AREA TO LIKELY BASED ON GOOD
MODEL CONSENSUS.

THE REST OF THE PERIOD LOOKS VERY UNSETTLED WITH ROUNDS OF
CONVECTION MAKING THE POSITION OF THE COLD FRONT HARD TO FIND.
HOWEVER IT APPEARS MODELS HAVE BUMPED UP THE TIMING OF THE MAIN COLD
FRONT TO WED...RATHER THAN WED NIGHT. HAVE LIKELY POPS IN FOR
WED...BUT BEFORE AND AFTER THAT CANNOT REALLY PIN DOWN ANY PERIODS
TO CONCENTRATE HIGH POPS ON...SO WILL CONTINUE TO BROADBRUSH HIGH
CHANCE POPS TUESDAY THRU TUE NIGHT AND AGAIN WED NIGHT.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
ISSUED AT 233 AM EDT MON MAY 20 2013

END OF AN ACTIVE WX PERIOD IS ANTICIPATED IN THE LONG TERM PORTION
OF THE FORECAST...AS LOW PRESSURE PULLS OUT OF THE AREA AND A
BROAD SURFACE RIDGE SETTLES INTO THE REGION DOWNSTREAM OF AN UPPER
RIDGE ACROSS THE CENTRAL PORTION OF THE COUNTRY. NOT OVERLY
PLEASED WITH ALLBLEND INITIALIZATION POPS BEYOND THURSDAY AS IT
WANTS TO INTRODUCE ANOTHER LENGTHY PERIOD OF SLIGHT CHANCE TO
CHANCE POPS OVER THE WEEKEND AND INTO NEXT WEEK...EVEN WITH THIS
SURFACE RIDGE ACROSS THE AREA AND LIMITED IF ANY UPPER LEVEL
SUPPORT FOR PRECIPITATION. HAVE GONE DRY FROM THURSDAY NIGHT ON.

ON TEMPS...EXPECTING NUMBERS CLOSER TO SEASONABLE LEVELS...IF NOT
SLIGHTLY BELOW AT TIMES THROUGHOUT THE PERIOD. IF DRY FORECAST
HOLDS...COULD MAKE FOR A VERY PLEASANT HOLIDAY WEEKEND ACROSS
CENTRAL INDIANA.

&&

.AVIATION /DISCUSSION FOR THE 20/06Z TAFS/...
ISSUED AT 1244 AM EDT SUN MAY 19 2013

VFR CONDITIONS EXPECTED DURING THE TAF PERIOD...EXCEPT HUF AND EVEN
MORE SO BMG COULD SEE SOME RESTRICTIONS TO VISIBILITY AFTER 08Z AS
DEW POINTS WERE IN THE UPPER 60S AND LOWER 70S THERE LATE THIS
EVENING AND WINDS WERE ONLY 3 KNOTS AT BMG. WOULD ALSO NOT RULE OUT
SOME LOW STRATUS AS MODEL TIME SECTIONS WERE SHOWING PLENTY OF LOW
LEVEL MOISTURE. WILL GO WITH SCATTERED CLOUDS BELOW 1000 FEET
OVERNIGHT AND MVFR FOG AT HUF AFTER 08Z AND MVFR AND TEMPO IFR AT
BMG. THE OTHER SITES SHOULD NOT SEE ANY FOG WITH WINDS REMAINING 5
KNOTS OR MORE AND WITH DEW POINTS A TAD LOWER IN THE MID 60S.

COULD SEE SOME THUNDERSTORMS AFTER DAYBREAK ESPECIALLY DURING THE
AFTERNOON...BUT WITH COVERAGE EXPECTED TO BE SCATTERED AT BEST AND
BEING SO FAR OUT...WILL HOLD OFF ON VCTS UNTIL AFTER 00Z TUESDAY
AS COVERAGE SHOULD BE A LITTLE BETTER THEN. SHOULD SEE SCATTERED TO
BROKEN DIURNAL VFR CU TOMORROW AFTERNOON. WINDS WILL BE INCREASING
TOMORROW WITH SOUTH AND SOUTHWEST WINDS INCREASING TO AROUND 15
KNOTS WITH GUSTS TO 23 KNOTS AFTER 14Z.


&&

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

$$

SYNOPSIS...SMF
NEAR TERM...SMF
SHORT TERM...SMF
LONG TERM....NIELD
AVIATION...MK

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

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

000
FXUS63 KIND 200633
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
233 AM EDT MON MAY 20 2013

.UPDATE...

THE LONG TERM SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 224 PM EDT SUN MAY 19 2013

A LARGE UPPER LOW CURRENTLY OVER THE PLAINS IS EXPECTED TO BRING
UNSETTLED WEATHER TO THE AREA THROUGH THURSDAY AS IT SLOWLY MOVES
EAST AND WEAKENS WITH TIME. HIGH PRESSURE IS EXPECTED TO BUILD IN
BEHIND THIS SYSTEM TOWARDS THE END OF THE WEEK. ANOTHER FRONTAL
SYSTEM MAY APPROACH THE AREA BY NEXT SUNDAY.

&&

.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 959 PM EDT SUN MAY 19 2013

FORECAST IS ON TRACK. SKIES HAVE CLEARED WITH LOSS OF HEATING. ONLY
EXPECT SOME SCATTERED CIRRUS AND MID CLOUD TO MOVE IN LATER TONIGHT
FROM CONVECTION TO OUR WEST.

DEWPOINT GRADIENT CONTINUES ACROSS THE FORECAST AREA WITH DEWPOINTS
IN THE LOWER 70S SOUTHWEST TO LOWER 60S NORTHEAST. IN AREAS WITH
HIGHER DEWPOINTS THERE IS SOME THOUGHT OF FOG DEVELOPMENT...BUT
WINDS SHOULD STAY UP ENOUGH TO KEEP MOST FOG AT BAY. THUS LEFT
MENTION OUT.

850MB WINDS INCREASE OVERNIGHT AS LOW LEVEL JET APPROACHES. SOME
CONCERN THAT ELEVATED STORMS COULD DEVELOP IN WARM ADVECTION...BUT
CONFIDENCE CONTINUES TO BE TOO LOW TO MENTION ANY POPS IN FORECAST.

TWEAKED TEMPERATURES UP A BIT AT SOME LOCATIONS GIVEN CURRENT
TRENDS...ESPECIALLY IN THE SOUTHWEST WITH THE HIGHER DEWPOINTS.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 224 PM EDT SUN MAY 19 2013

MAIN FEATURE DURING THIS PERIOD WILL BE THE LARGE UPPER LOW OVER THE
PLAINS THAT IS EXPECTED TO GRADUALLY OPEN UP AND MOVE INTO THE
MIDWEST BY WEDNESDAY...KEEPING THE SHORT TERM UNSETTLED.

SOME OF THE FINER SCALE MODELS SUGGEST THERE MAY SOME SORT OF
BOUNDARY...POSSIBLY ORIGINATING FROM CONVECTIVE ACTIVITY TO THE
WEST TONIGHT...THAT MAY MOVE INTO THE AREA AROUND MIDDAY ON
MONDAY. AIR MASS IS PROGGED TO BECOME VERY UNSTABLE ON
MONDAY...LI/S DOWN TO ABOUT -8...UNDERNEATH STEEP MID LEVEL LAPSE
RATES. WILL GO WITH CHANCE POPS STARTING AROUND MIDDAY AND ON INTO
THE AFTERNOON.

AFTER MONDAY...DETAILS BECOME A BIT MORE MURKY AS ROUNDS OF
CONVECTION ASSOCIATED WITH THIS SYSTEM MAY TEND TO BLUR THE COLD
FRONT POSITION. MODEL DATA SUGGEST ACTUAL COLD FRONT MAY NOT MOVE
THROUGH UNTIL WEDNESDAY NIGHT OR LATER. MODEL DATA DOES SUGGEST
LAPSE RATES GRADUALLY BECOME POORER WITH TIME AS AIR MASS GETS
WORKED OVER...ALTHOUGH DEEP LAYER SHEAR MAY TEND TO INCREASE SOME
TOWARDS TUESDAY AND WEDNESDAY. AT THIS POINT...CAN/T REALLY PIN DOWN
ANY PERIODS TO CONCENTRATE POPS ON...SO WITH BROADBRUSH HIGH CHANCE
POPS FROM MONDAY NIGHT THROUGH WEDNESDAY.

PROGGED LOW LEVEL THICKNESSES SUGGEST THE GFS MOS HIGHS FOR MONDAY
AND TUESDAY MAY BE A BIT ON THE WARM SIDE...ESPECIALLY WITH THE
POTENTIAL FOR CONVECTION OR ITS REMNANTS AROUND. WILL NUDGE THE
HIGHS DOWN A BIT. LOWS LOOK OK.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
ISSUED AT 233 AM EDT MON MAY 20 2013

END OF AN ACTIVE WX PERIOD IS ANTICIPATED IN THE LONG TERM PORTION
OF THE FORECAST...AS LOW PRESSURE PULLS OUT OF THE AREA AND A
BROAD SURFACE RIDGE SETTLES INTO THE REGION DOWNSTREAM OF AN UPPER
RIDGE ACROSS THE CENTRAL PORTION OF THE COUNTRY. NOT OVERLY
PLEASED WITH ALLBLEND INITIALIZATION POPS BEYOND THURSDAY AS IT
WANTS TO INTRODUCE ANOTHER LENGTHY PERIOD OF SLIGHT CHANCE TO
CHANCE POPS OVER THE WEEKEND AND INTO NEXT WEEK...EVEN WITH THIS
SURFACE RIDGE ACROSS THE AREA AND LIMITED IF ANY UPPER LEVEL
SUPPORT FOR PRECIPITATION. HAVE GONE DRY FROM THURSDAY NIGHT ON.

ON TEMPS...EXPECTING NUMBERS CLOSER TO SEASONABLE LEVELS...IF NOT
SLIGHTLY BELOW AT TIMES THROUGHOUT THE PERIOD. IF DRY FORECAST
HOLDS...COULD MAKE FOR A VERY PLEASANT HOLIDAY WEEKEND ACROSS
CENTRAL INDIANA.

&&

.AVIATION /DISCUSSION FOR THE 20/06Z TAFS/...
ISSUED AT 1244 AM EDT SUN MAY 19 2013

VFR CONDITIONS EXPECTED DURING THE TAF PERIOD...EXCEPT HUF AND EVEN
MORE SO BMG COULD SEE SOME RESTRICTIONS TO VISIBILITY AFTER 08Z AS
DEW POINTS WERE IN THE UPPER 60S AND LOWER 70S THERE LATE THIS
EVENING AND WINDS WERE ONLY 3 KNOTS AT BMG. WOULD ALSO NOT RULE OUT
SOME LOW STRATUS AS MODEL TIME SECTIONS WERE SHOWING PLENTY OF LOW
LEVEL MOISTURE. WILL GO WITH SCATTERED CLOUDS BELOW 1000 FEET
OVERNIGHT AND MVFR FOG AT HUF AFTER 08Z AND MVFR AND TEMPO IFR AT
BMG. THE OTHER SITES SHOULD NOT SEE ANY FOG WITH WINDS REMAINING 5
KNOTS OR MORE AND WITH DEW POINTS A TAD LOWER IN THE MID 60S.

COULD SEE SOME THUNDERSTORMS AFTER DAYBREAK ESPECIALLY DURING THE
AFTERNOON...BUT WITH COVERAGE EXPECTED TO BE SCATTERED AT BEST AND
BEING SO FAR OUT...WILL HOLD OFF ON VCTS UNTIL AFTER 00Z TUESDAY
AS COVERAGE SHOULD BE A LITTLE BETTER THEN. SHOULD SEE SCATTERED TO
BROKEN DIURNAL VFR CU TOMORROW AFTERNOON. WINDS WILL BE INCREASING
TOMORROW WITH SOUTH AND SOUTHWEST WINDS INCREASING TO AROUND 15
KNOTS WITH GUSTS TO 23 KNOTS AFTER 14Z.

&&

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

&&

$$

SYNOPSIS...JAS
NEAR TERM...50
SHORT TERM...JAS
LONG TERM....NIELD
AVIATION...MK

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

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

000
FXUS63 KIND 200444
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1244 AM EDT MON MAY 20 2013

.UPDATE...

THE AVIATION SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 224 PM EDT SUN MAY 19 2013

A LARGE UPPER LOW CURRENTLY OVER THE PLAINS IS EXPECTED TO BRING
UNSETTLED WEATHER TO THE AREA THROUGH THURSDAY AS IT SLOWLY MOVES
EAST AND WEAKENS WITH TIME. HIGH PRESSURE IS EXPECTED TO BUILD IN
BEHIND THIS SYSTEM TOWARDS THE END OF THE WEEK. ANOTHER FRONTAL
SYSTEM MAY APPROACH THE AREA BY NEXT SUNDAY.

&&

.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 959 PM EDT SUN MAY 19 2013

FORECAST IS ON TRACK. SKIES HAVE CLEARED WITH LOSS OF HEATING. ONLY
EXPECT SOME SCATTERED CIRRUS AND MID CLOUD TO MOVE IN LATER TONIGHT
FROM CONVECTION TO OUR WEST.

DEWPOINT GRADIENT CONTINUES ACROSS THE FORECAST AREA WITH DEWPOINTS
IN THE LOWER 70S SOUTHWEST TO LOWER 60S NORTHEAST. IN AREAS WITH
HIGHER DEWPOINTS THERE IS SOME THOUGHT OF FOG DEVELOPMENT...BUT
WINDS SHOULD STAY UP ENOUGH TO KEEP MOST FOG AT BAY. THUS LEFT
MENTION OUT.

850MB WINDS INCREASE OVERNIGHT AS LOW LEVEL JET APPROACHES. SOME
CONCERN THAT ELEVATED STORMS COULD DEVELOP IN WARM ADVECTION...BUT
CONFIDENCE CONTINUES TO BE TOO LOW TO MENTION ANY POPS IN FORECAST.

TWEAKED TEMPERATURES UP A BIT AT SOME LOCATIONS GIVEN CURRENT
TRENDS...ESPECIALLY IN THE SOUTHWEST WITH THE HIGHER DEWPOINTS.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 224 PM EDT SUN MAY 19 2013

MAIN FEATURE DURING THIS PERIOD WILL BE THE LARGE UPPER LOW OVER THE
PLAINS THAT IS EXPECTED TO GRADUALLY OPEN UP AND MOVE INTO THE
MIDWEST BY WEDNESDAY...KEEPING THE SHORT TERM UNSETTLED.

SOME OF THE FINER SCALE MODELS SUGGEST THERE MAY SOME SORT OF
BOUNDARY...POSSIBLY ORIGINATING FROM CONVECTIVE ACTIVITY TO THE
WEST TONIGHT...THAT MAY MOVE INTO THE AREA AROUND MIDDAY ON
MONDAY. AIR MASS IS PROGGED TO BECOME VERY UNSTABLE ON
MONDAY...LI/S DOWN TO ABOUT -8...UNDERNEATH STEEP MID LEVEL LAPSE
RATES. WILL GO WITH CHANCE POPS STARTING AROUND MIDDAY AND ON INTO
THE AFTERNOON.

AFTER MONDAY...DETAILS BECOME A BIT MORE MURKY AS ROUNDS OF
CONVECTION ASSOCIATED WITH THIS SYSTEM MAY TEND TO BLUR THE COLD
FRONT POSITION. MODEL DATA SUGGEST ACTUAL COLD FRONT MAY NOT MOVE
THROUGH UNTIL WEDNESDAY NIGHT OR LATER. MODEL DATA DOES SUGGEST
LAPSE RATES GRADUALLY BECOME POORER WITH TIME AS AIR MASS GETS
WORKED OVER...ALTHOUGH DEEP LAYER SHEAR MAY TEND TO INCREASE SOME
TOWARDS TUESDAY AND WEDNESDAY. AT THIS POINT...CAN/T REALLY PIN DOWN
ANY PERIODS TO CONCENTRATE POPS ON...SO WITH BROADBRUSH HIGH CHANCE
POPS FROM MONDAY NIGHT THROUGH WEDNESDAY.

PROGGED LOW LEVEL THICKNESSES SUGGEST THE GFS MOS HIGHS FOR MONDAY
AND TUESDAY MAY BE A BIT ON THE WARM SIDE...ESPECIALLY WITH THE
POTENTIAL FOR CONVECTION OR ITS REMNANTS AROUND. WILL NUDGE THE
HIGHS DOWN A BIT. LOWS LOOK OK.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 224 PM EDT SUN MAY 19 2013

ECMWF AND GFS BOTH INDICATE A FRONTAL BOUNDARY AND ASSOCIATED UPPER
TROUGH EXITING THE RGN ON WEDNESDAY NIGHT AND EARLY ON THURSDAY. A
STRONG RIDGE ALOFT THEN BUILDS ACROSS THE OHIO VALLEY FOR FRIDAY AND
SATURDAY FROM THE CENTRAL PLAINS ALONG WITH COOLER AND DRY NW FLOW.
THUS WILL KEEP SOME CHCS FOR TSRA ON WEDNESDAY NIGHT AND SHRA ON
THURSDAY IN THE CYCLONIC FLOW ON THURSDAY. HOWEVER DRY WEATHER WILL
BE EXPECTED AS THE WORK WEEK CONCLUDES ON FRIDAY ALONG WITH TEMPS AT
OR ONLY SLIGHTLY ABOVE NORMALS.

ECMWF HINTS AT A WARM FRONT AND A WEAK S/W WAVE PUSHING INTO THE
AREA ON SUNDAY AND FOR NOW HAVE INCLUDED SOME LOW CHC POPS.

&&

.AVIATION /DISCUSSION FOR THE 20/06Z TAFS/...
ISSUED AT 1244 AM EDT SUN MAY 19 2013

VFR CONDITIONS EXPECTED DURING THE TAF PERIOD...EXCEPT HUF AND EVEN
MORE SO BMG COULD SEE SOME RESTRICTIONS TO VISIBILITY AFTER 08Z AS
DEW POINTS WERE IN THE UPPER 60S AND LOWER 70S THERE LATE THIS
EVENING AND WINDS WERE ONLY 3 KNOTS AT BMG. WOULD ALSO NOT RULE OUT
SOME LOW STRATUS AS MODEL TIME SECTIONS WERE SHOWING PLENTY OF LOW
LEVEL MOISTURE. WILL GO WITH SCATTERED CLOUDS BELOW 1000 FEET
OVERNIGHT AND MVFR FOG AT HUF AFTER 08Z AND MVFR AND TEMPO IFR AT
BMG. THE OTHER SITES SHOULD NOT SEE ANY FOG WITH WINDS REMAINING 5
KNOTS OR MORE AND WITH DEW POINTS A TAD LOWER IN THE MID 60S.

COULD SEE SOME THUNDERSTORMS AFTER DAYBREAK ESPECIALLY DURING THE
AFTERNOON...BUT WITH COVERAGE EXPECTED TO BE SCATTERED AT BEST AND
BEING SO FAR OUT...WILL HOLD OFF ON VCTS UNTIL AFTER 00Z TUESDAY
AS COVERAGE SHOULD BE A LITTLE BETTER THEN. SHOULD SEE SCATTERED TO
BROKEN DIURNAL VFR CU TOMORROW AFTERNOON. WINDS WILL BE INCREASING
TOMORROW WITH SOUTH AND SOUTHWEST WINDS INCREASING TO AROUND 15
KNOTS WITH GUSTS TO 23 KNOTS AFTER 14Z.

&&

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

&&

$$

SYNOPSIS...JAS
NEAR TERM...50
SHORT TERM...JAS
LONG TERM....PUMA
AVIATION...MK

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

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

000
FXUS63 KIND 200224
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1023 PM EDT SUN MAY 19 2013

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

&&

.SYNOPSIS...
ISSUED AT 224 PM EDT SUN MAY 19 2013

A LARGE UPPER LOW CURRENTLY OVER THE PLAINS IS EXPECTED TO BRING
UNSETTLED WEATHER TO THE AREA THROUGH THURSDAY AS IT SLOWLY MOVES
EAST AND WEAKENS WITH TIME. HIGH PRESSURE IS EXPECTED TO BUILD IN
BEHIND THIS SYSTEM TOWARDS THE END OF THE WEEK. ANOTHER FRONTAL
SYSTEM MAY APPROACH THE AREA BY NEXT SUNDAY.

&&

.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 959 PM EDT SUN MAY 19 2013

FORECAST IS ON TRACK. SKIES HAVE CLEARED WITH LOSS OF HEATING. ONLY
EXPECT SOME SCATTERED CIRRUS AND MID CLOUD TO MOVE IN LATER TONIGHT
FROM CONVECTION TO OUR WEST.

DEWPOINT GRADIENT CONTINUES ACROSS THE FORECAST AREA WITH DEWPOINTS
IN THE LOWER 70S SOUTHWEST TO LOWER 60S NORTHEAST. IN AREAS WITH
HIGHER DEWPOINTS THERE IS SOME THOUGHT OF FOG DEVELOPMENT...BUT
WINDS SHOULD STAY UP ENOUGH TO KEEP MOST FOG AT BAY. THUS LEFT
MENTION OUT.

850MB WINDS INCREASE OVERNIGHT AS LOW LEVEL JET APPROACHES. SOME
CONCERN THAT ELEVATED STORMS COULD DEVELOP IN WARM ADVECTION...BUT
CONFIDENCE CONTINUES TO BE TOO LOW TO MENTION ANY POPS IN FORECAST.

TWEAKED TEMPERATURES UP A BIT AT SOME LOCATIONS GIVEN CURRENT
TRENDS...ESPECIALLY IN THE SOUTHWEST WITH THE HIGHER DEWPOINTS.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 224 PM EDT SUN MAY 19 2013

MAIN FEATURE DURING THIS PERIOD WILL BE THE LARGE UPPER LOW OVER THE
PLAINS THAT IS EXPECTED TO GRADUALLY OPEN UP AND MOVE INTO THE
MIDWEST BY WEDNESDAY...KEEPING THE SHORT TERM UNSETTLED.

SOME OF THE FINER SCALE MODELS SUGGEST THERE MAY SOME SORT OF
BOUNDARY...POSSIBLY ORIGINATING FROM CONVECTIVE ACTIVITY TO THE
WEST TONIGHT...THAT MAY MOVE INTO THE AREA AROUND MIDDAY ON
MONDAY. AIR MASS IS PROGGED TO BECOME VERY UNSTABLE ON
MONDAY...LI/S DOWN TO ABOUT -8...UNDERNEATH STEEP MID LEVEL LAPSE
RATES. WILL GO WITH CHANCE POPS STARTING AROUND MIDDAY AND ON INTO
THE AFTERNOON.

AFTER MONDAY...DETAILS BECOME A BIT MORE MURKY AS ROUNDS OF
CONVECTION ASSOCIATED WITH THIS SYSTEM MAY TEND TO BLUR THE COLD
FRONT POSITION. MODEL DATA SUGGEST ACTUAL COLD FRONT MAY NOT MOVE
THROUGH UNTIL WEDNESDAY NIGHT OR LATER. MODEL DATA DOES SUGGEST
LAPSE RATES GRADUALLY BECOME POORER WITH TIME AS AIR MASS GETS
WORKED OVER...ALTHOUGH DEEP LAYER SHEAR MAY TEND TO INCREASE SOME
TOWARDS TUESDAY AND WEDNESDAY. AT THIS POINT...CAN/T REALLY PIN DOWN
ANY PERIODS TO CONCENTRATE POPS ON...SO WITH BROADBRUSH HIGH CHANCE
POPS FROM MONDAY NIGHT THROUGH WEDNESDAY.

PROGGED LOW LEVEL THICKNESSES SUGGEST THE GFS MOS HIGHS FOR MONDAY
AND TUESDAY MAY BE A BIT ON THE WARM SIDE...ESPECIALLY WITH THE
POTENTIAL FOR CONVECTION OR ITS REMNANTS AROUND. WILL NUDGE THE
HIGHS DOWN A BIT. LOWS LOOK OK.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 224 PM EDT SUN MAY 19 2013

ECMWF AND GFS BOTH INDICATE A FRONTAL BOUNDARY AND ASSOCIATED UPPER
TROUGH EXITING THE RGN ON WEDNESDAY NIGHT AND EARLY ON THURSDAY. A
STRONG RIDGE ALOFT THEN BUILDS ACROSS THE OHIO VALLEY FOR FRIDAY AND
SATURDAY FROM THE CENTRAL PLAINS ALONG WITH COOLER AND DRY NW FLOW.
THUS WILL KEEP SOME CHCS FOR TSRA ON WEDNESDAY NIGHT AND SHRA ON
THURSDAY IN THE CYCLONIC FLOW ON THURSDAY. HOWEVER DRY WEATHER WILL
BE EXPECTED AS THE WORK WEEK CONCLUDES ON FRIDAY ALONG WITH TEMPS AT
OR ONLY SLIGHTLY ABOVE NORMALS.

ECMWF HINTS AT A WARM FRONT AND A WEAK S/W WAVE PUSHING INTO THE
AREA ON SUNDAY AND FOR NOW HAVE INCLUDED SOME LOW CHC POPS.

&&

.AVIATION /DISCUSSION FOR THE 200300Z IND TAF UPDATE/...

ISSUED AT 1023 PM EDT SUN MAY 19 2013

NO CHANGES NEEDED TO TAF.

PREVIOUS DISCUSSION FOLLOWS...

VFR CONDITIONS EXPECTED TONIGHT WITH ONLY HIGH CLOUDS AS DIURNAL CU
DISSIPATES. MODELS SHOWING LINGERING LOW LEVEL MOISTURE...BUT THINK
FOG WILL NOT BE A PROBLEM LIKE LAST NIGHT AS SURFACE PRESSURE
GRADIENT PICKS UP AHEAD OF THE PLAINS FRONTAL SYSTEM WHICH SHOULD
KEEP SOUTH WINDS 5 KNOTS OR MORE. THE EXCEPTION COULD BE AT
BMG...WHERE GRADIENT WILL BE A BIT WEAKER WHICH SHOULD ALLOW SOUTH
WINDS TO DROP BELOW 5 KNOTS. THIS COULD ONCE AGAIN RESULT IN SOME
IFR FOG AT BMG AFTER 08Z THROUGH ABOUT 13Z. WOULD ALSO NOT RULE OUT
SOME LOW STRATUS OVERNIGHT...BUT FOR NOW WILL ONLY GO WITH SCATTERED
LOW STRATUS AT IND AND BMG AFTER 08Z.

WOULD NOT RULE OUT THUNDERSTORMS AFTER 14Z TOMORROW...BUT WITH
COVERAGE EXPECTED TO BE SCATTERED AT BEST AND BEING SO FAR
OUT...WILL HOLD OFF ON VCTS FOR NOW. SHOULD SEE SCATTERED TO BROKEN
DIURNAL VFR CU TOMORROW AFTERNOON. WINDS WILL BE INCREASING TOMORROW
WITH SOUTH AND SOUTHWEST WINDS INCREASING TO AROUND 15 KNOTS WITH
GUSTS TO 23 KNOTS AFTER 14Z.

&&

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

$$

SYNOPSIS...JAS
NEAR TERM...50
SHORT TERM...JAS
LONG TERM....PUMA
AVIATION...MK

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

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

000
FXUS63 KIND 200159
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
959 PM EDT SUN MAY 19 2013

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

&&

.SYNOPSIS...
ISSUED AT 224 PM EDT SUN MAY 19 2013

A LARGE UPPER LOW CURRENTLY OVER THE PLAINS IS EXPECTED TO BRING
UNSETTLED WEATHER TO THE AREA THROUGH THURSDAY AS IT SLOWLY MOVES
EAST AND WEAKENS WITH TIME. HIGH PRESSURE IS EXPECTED TO BUILD IN
BEHIND THIS SYSTEM TOWARDS THE END OF THE WEEK. ANOTHER FRONTAL
SYSTEM MAY APPROACH THE AREA BY NEXT SUNDAY.

&&

.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 959 PM EDT SUN MAY 19 2013

FORECAST IS ON TRACK. SKIES HAVE CLEARED WITH LOSS OF HEATING. ONLY
EXPECT SOME SCATTERED CIRRUS AND MID CLOUD TO MOVE IN LATER TONIGHT
FROM CONVECTION TO OUR WEST.

DEWPOINT GRADIENT CONTINUES ACROSS THE FORECAST AREA WITH DEWPOINTS
IN THE LOWER 70S SOUTHWEST TO LOWER 60S NORTHEAST. IN AREAS WITH
HIGHER DEWPOINTS THERE IS SOME THOUGHT OF FOG DEVELOPMENT...BUT
WINDS SHOULD STAY UP ENOUGH TO KEEP MOST FOG AT BAY. THUS LEFT
MENTION OUT.

850MB WINDS INCREASE OVERNIGHT AS LOW LEVEL JET APPROACHES. SOME
CONCERN THAT ELEVATED STORMS COULD DEVELOP IN WARM ADVECTION...BUT
CONFIDENCE CONTINUES TO BE TOO LOW TO MENTION ANY POPS IN FORECAST.

TWEAKED TEMPERATURES UP A BIT AT SOME LOCATIONS GIVEN CURRENT
TRENDS...ESPECIALLY IN THE SOUTHWEST WITH THE HIGHER DEWPOINTS.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 224 PM EDT SUN MAY 19 2013

MAIN FEATURE DURING THIS PERIOD WILL BE THE LARGE UPPER LOW OVER THE
PLAINS THAT IS EXPECTED TO GRADUALLY OPEN UP AND MOVE INTO THE
MIDWEST BY WEDNESDAY...KEEPING THE SHORT TERM UNSETTLED.

SOME OF THE FINER SCALE MODELS SUGGEST THERE MAY SOME SORT OF
BOUNDARY...POSSIBLY ORIGINATING FROM CONVECTIVE ACTIVITY TO THE
WEST TONIGHT...THAT MAY MOVE INTO THE AREA AROUND MIDDAY ON
MONDAY. AIR MASS IS PROGGED TO BECOME VERY UNSTABLE ON
MONDAY...LI/S DOWN TO ABOUT -8...UNDERNEATH STEEP MID LEVEL LAPSE
RATES. WILL GO WITH CHANCE POPS STARTING AROUND MIDDAY AND ON INTO
THE AFTERNOON.

AFTER MONDAY...DETAILS BECOME A BIT MORE MURKY AS ROUNDS OF
CONVECTION ASSOCIATED WITH THIS SYSTEM MAY TEND TO BLUR THE COLD
FRONT POSITION. MODEL DATA SUGGEST ACTUAL COLD FRONT MAY NOT MOVE
THROUGH UNTIL WEDNESDAY NIGHT OR LATER. MODEL DATA DOES SUGGEST
LAPSE RATES GRADUALLY BECOME POORER WITH TIME AS AIR MASS GETS
WORKED OVER...ALTHOUGH DEEP LAYER SHEAR MAY TEND TO INCREASE SOME
TOWARDS TUESDAY AND WEDNESDAY. AT THIS POINT...CAN/T REALLY PIN DOWN
ANY PERIODS TO CONCENTRATE POPS ON...SO WITH BROADBRUSH HIGH CHANCE
POPS FROM MONDAY NIGHT THROUGH WEDNESDAY.

PROGGED LOW LEVEL THICKNESSES SUGGEST THE GFS MOS HIGHS FOR MONDAY
AND TUESDAY MAY BE A BIT ON THE WARM SIDE...ESPECIALLY WITH THE
POTENTIAL FOR CONVECTION OR ITS REMNANTS AROUND. WILL NUDGE THE
HIGHS DOWN A BIT. LOWS LOOK OK.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 224 PM EDT SUN MAY 19 2013

ECMWF AND GFS BOTH INDICATE A FRONTAL BOUNDARY AND ASSOCIATED UPPER
TROUGH EXITING THE RGN ON WEDNESDAY NIGHT AND EARLY ON THURSDAY. A
STRONG RIDGE ALOFT THEN BUILDS ACROSS THE OHIO VALLEY FOR FRIDAY AND
SATURDAY FROM THE CENTRAL PLAINS ALONG WITH COOLER AND DRY NW FLOW.
THUS WILL KEEP SOME CHCS FOR TSRA ON WEDNESDAY NIGHT AND SHRA ON
THURSDAY IN THE CYCLONIC FLOW ON THURSDAY. HOWEVER DRY WEATHER WILL
BE EXPECTED AS THE WORK WEEK CONCLUDES ON FRIDAY ALONG WITH TEMPS AT
OR ONLY SLIGHTLY ABOVE NORMALS.

ECMWF HINTS AT A WARM FRONT AND A WEAK S/W WAVE PUSHING INTO THE
AREA ON SUNDAY AND FOR NOW HAVE INCLUDED SOME LOW CHC POPS.

&&

.AVIATION /DISCUSSION FOR THE 200000Z TAF ISSUANCE/...

ISSUED AT 645 PM EDT SUN MAY 19 2013

VFR CONDITIONS EXPECTED TONIGHT WITH ONLY HIGH CLOUDS AS DIURNAL CU
DISSIPATES. MODELS SHOWING LINGERING LOW LEVEL MOISTURE...BUT THINK
FOG WILL NOT BE A PROBLEM LIKE LAST NIGHT AS SURFACE PRESSURE
GRADIENT PICKS UP AHEAD OF THE PLAINS FRONTAL SYSTEM WHICH SHOULD
KEEP SOUTH WINDS 5 KNOTS OR MORE. THE EXCEPTION COULD BE AT
BMG...WHERE GRADIENT WILL BE A BIT WEAKER WHICH SHOULD ALLOW SOUTH
WINDS TO DROP BELOW 5 KNOTS. THIS COULD ONCE AGAIN RESULT IN SOME
IFR FOG AT BMG AFTER 08Z THROUGH ABOUT 13Z. WOULD ALSO NOT RULE OUT
SOME LOW STRATUS OVERNIGHT...BUT FOR NOW WILL ONLY GO WITH SCATTERED
LOW STRATUS AT IND AND BMG AFTER 08Z.

WOULD NOT RULE OUT THUNDERSTORMS AFTER 14Z TOMORROW...BUT WITH
COVERAGE EXPECTED TO BE SCATTERED AT BEST AND BEING SO FAR
OUT...WILL HOLD OFF ON VCTS FOR NOW. SHOULD SEE SCATTERED TO BROKEN
DIURNAL VFR CU TOMORROW AFTERNOON. WINDS WILL BE INCREASING TOMORROW
WITH SOUTH AND SOUTHWEST WINDS INCREASING TO AROUND 15 KNOTS WITH
GUSTS TO 23 KNOTS AFTER 14Z.

&&

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

$$

SYNOPSIS...JAS
NEAR TERM...50
SHORT TERM...JAS
LONG TERM....PUMA
AVIATION...MK

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

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

000
FXUS63 KIWX 200026
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
826 PM EDT SUN MAY 19 2013

.SYNOPSIS...
ISSUED AT 504 PM EDT SUN MAY 19 2013

SKIES WILL REMAIN MOSTLY CLEAR TO PARTLY CLOUDY TONIGHT...WITH LOW
TEMPERATURES MAINLY IN THE MID 60S. A LOW PRESSURE SYSTEM WILL MAKE
ITS WAY ACROSS THE REGION EARLY THIS WEEK...BRINGING CHANCES FOR
SHOWERS AND THUNDERSTORMS THROUGHOUT THE WEEK. TEMPERATURES ARE
EXPECTED TO BE FAIRLY WARM MONDAY AND TUESDAY BEFORE DROPPING DOWN
TO MORE SEASONABLE LEVELS BY THE END OF THE WEEK.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 320 PM EDT SUN MAY 19 2013

TIGHT DEWPOINT GRADIENT WHICH HAD BEEN EVER PERSISTENT ACROSS OUR
AREA HAS FINALLY BEEN ERRADICATED AS LOW TO MID 60S DEWPOINTS HAVE
NOW OVERSPREAD THE ENTIRE CWA. THIS INCREASE IN SURFACE DEWPOINTS
HAS YIELDED SBCAPE VALUES BETWEEN 1500 AND 2000 J/KG. WITH A LACK OF
ANY SIGNIFICANT FORCING...NOTHING MORE THAN A SCATTERED TO BROKEN CU
DECK HAS BEEN ABLE TO DEVELOP.  THIS CU FIELD WILL DISSIPATE BY
LATE AFTERNOON AS A DEEP EML/CAPPING INVERSION OVERSPREADS THE CWA
FROM THE WEST.

PRECIP POTENTIAL FOR TONIGHT REMAINS COMPLICATED AS SIGNIFICANT
MODEL SPREAD EXISTS REGARDING THE LOCATION AND PERSISTENCE OF
REMNANT CONVECTION FROM IOWA/MISSOURI SEVERE WEATHER TODAY. GLOBAL
MODELS KEEP CONVECTION NORTHWEST OF OUR CWA...WHILE HI
RESOLUTION/CONVECTION ALLOWING MODELS BRING PRECIP INTO AT LEAST THE
WESTERN HALF OF THE CWA AFTER 05Z BEFORE COMPLETELY DISSIPATING.
KEPT SLIGHT CHANCE POPS IN THE NORTHWEST OVERNIGHT WITH THE ONLY
CHANGE BEING A SLIGHTLY EARLIER ARRIVAL TIME AS HRRR GUIDANCE IS
CONSISTENTLY BRINGING CONVECTION INTO WESTERN AREAS BETWEEN 03-04Z.

TEMPS WILL WARM INTO THE UPPER 80S ON MONDAY WITH A FEW LOCATIONS
LIKELY REACHING 90 DEGREES. THESE ABOVE NORMAL TEMPS COUPLED WITH
UPPER 60S TO NEAR 70 DEWPOINTS WILL MAKE THE MONDAY AIRMASS QUITE
UNSTABLE. KEPT POPS IN THE LOW CHANCE RANGE AS UNCERTAINTIES
REGARDING THE STRENGTH OF THE CAP AND ANY CONVECTIVE DEBRIS WHICH
MAY OVERSPREAD THE AREA LIMIT CONFIDENCE. IF CONVECTION CAN
DEVELOP...SEVERE POTENTIAL WILL INCREASE THROUGH TIME AS A 50-60 KT
MID-LEVEL JET STREAK CLIPS THE NORTHWEST PORTION OF OUR FORECAST
AREA NEAR 21Z AND IMPROVES THE SHEAR PROFILE.

&&

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 320 PM EDT SUN MAY 19 2013

FCST PERIOD TO BEGIN WITH SFC LOW AND VERTICALLY STACKED CLOSED
UPPER LOW OVER THE NORTHERN PLAINS/UPPER MIDWEST. BEST FOCUS AND
FORCING FOR CONVECTIVE INITIATION HEADING INTO MONDAY EVENING WILL
BE TO THE WEST OF OUR AREA DESPITE BEING IN A VERY UNSTABLE WARM
SECTOR WITH CAPES AOA 3000J/KG OVER MUCH OF THE CWA. 500MB RIDGE
SHIFTS EAST OF THE AREA MON NITE AND BREAKDOWN OF THICKNESS RIDGE
WILL PROVIDE AN OPPORTUNITY FOR CONVECTION TO WORK INTO THE WESTERN
CWA 06-12Z TUE. GOOD MOISTURE ADVECTION ON A 40-50KT LLJ ALONG WITH
A 50-60KT MID LEVEL SPEED MAX WILL ACCOMPANY SFC PRE-FRONTAL TROF ON
TUE BRINGING GOOD CONVECTIVE POTENTIAL INTO THE AREA. UNCERTAINTY
WILL BE IN ABILITY FOR DESTABILIZATION...PUTTING SEVERE POTENTIAL IN
QUESTION. MAIN SFC FRONT TO FOLLOW ON WED WHICH WILL KEEP LIKELY
POPS FOR SH/TSRA GOING DURING THE DAY. SECONDARY FRONT THEN SET TO
MOVE THRU ON THURSDAY BEFORE ENTIRE SYSTEM FINALLY KICKS EAST OF OUR
AREA AND SETS THE STAGE FOR A COOLER BUT PLEASANT START TO THE
MEMORIAL DAY WEEKEND AS CANADIAN HIGH PRESSURE BUILDS INTO THE GREAT
LAKES REGION ON FRI/SAT. GFS AND ECMWF TRENDING TOWARD A MUCH
DIFFERENT SOLN COMPARED TO EARLIER RUNS FOR THE REST OF THE HOLIDAY
WEEKEND. WHAT WAS ONCE AN AMPLIFIED NW FLOW PATTERN WITH A
RE-ENFORCING DRY CANADIAN AIRMASS IS NOW BEING OFFERED AS A
TRANSITION TO A MORE ZONAL PATTERN AND KICKING SHORTWAVE DISTURBANCE
INTO THE REGION AND A CHANCE FOR PRECIP SUNDAY. NOT EAGER TO BUY
INTO THIS SOLN JUST YET...ESPECIALLY GIVEN THAT EVEN THE HIGHER END
OF THE ENSEMBLE MEMBERS HAVE POPS BELOW CLIMO. THAT AND GIVEN ITS IN
DAY 7 WILL OPT TO CONTINUE WITH DRY FCST FOR NOW AND WAIT TO SEE IF
TREND CONTINUES AND STRONGER SIGNAL IN MODEL GUIDANCE PRESENTS
ITSELF.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 825 PM EDT SUN MAY 19 2013

VFR MET CONDITIONS CONTINUE ODDS ON FAVORITE THROUGH THE FORECAST
PERIOD. INTENSE CONVECTIVE UPSTREAM TIED TO PLAINS DRYLINE/PVU
ANOMALY PUNCHING THROUGH EASTERN KS. WITH NORTHERN INDIANA WELL
REMOVED FROM BELT OF STRONGEST SOUTHWESTERLIES AND SECURELY CAPPED
AT THIS TIME...THE PRIME FOCUS AREA FOR COLLOCATED INSTABILITY AND
FORCED ASCENT WILL REMAIN WELL SOUTHWEST-WEST-NORTHWEST OF
NORTHERN INDIANA TERMINAL SITES. A GRADUAL UPTICK IN CONDITIONAL
PROBABILITIES FOR TSRA SEEN LATE IN FORECAST PERIOD...ESPECIALLY
INTO NORTHWEST INDIANA/KSBN VCNTY AS UPPER LOW COALESCES ACROSS
ND/SD/MN BORDER REGION BY 00 UTC TUE. STILL...CONVECTION MORE
LIKELY THAN NOT TO REMAIN UPSTREAM. WITH INITIATION FOCUSED ALONG
WARM FRONT EXTENSION ACROSS WISCONSIN...AND A SECONDARY AREA WELL
TO THE SOUTHWEST...WITHIN MAXIMUM LATE AFTERNOON DESTABILIZATION
ACROSS WEST CENTRAL ILLINOIS SOUTHWEST INTO OZARKS.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...KG
SHORT TERM...BENTLEY
LONG TERM...JAL
AVIATION...MURPHY


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIND 192245
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
645 PM EDT SUN MAY 19 2013

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

&&

.SYNOPSIS...
ISSUED AT 224 PM EDT SUN MAY 19 2013

A LARGE UPPER LOW CURRENTLY OVER THE PLAINS IS EXPECTED TO BRING
UNSETTLED WEATHER TO THE AREA THROUGH THURSDAY AS IT SLOWLY MOVES
EAST AND WEAKENS WITH TIME. HIGH PRESSURE IS EXPECTED TO BUILD IN
BEHIND THIS SYSTEM TOWARDS THE END OF THE WEEK. ANOTHER FRONTAL
SYSTEM MAY APPROACH THE AREA BY NEXT SUNDAY.

&&

.NEAR TERM /TONIGHT/...
ISSUED AT 224 PM EDT SUN MAY 19 2013

MODEL DATA SUGGEST FAIRLY STRONG 850MB WARM ADVECTION WILL BE
DEVELOPING ACROSS THE AREA BY LATE TONIGHT AS A 40-45KT LOW LEVEL
JET IS PROGGED TO NOSE TOWARDS INTO WESTERN INDIANA BY SUNRISE
MONDAY. SOME CONCERN THAT THIS MAY LEAD TO SOME ELEVATED CONVECTION
DURING THE PRE DAWN HOURS OF MONDAY GIVEN THE VERY STEEP MID LEVEL
LAPSE RATES EXPECTED OVER THE AREA. MODELS INDICATE SOME ENHANCED
MOISTURE IN THE PRECIPITATION BEARING LAYER AS WELL. AT THIS
POINT...DON/T THINK COVERAGE/POTENTIAL IS HIGH ENOUGH FOR A
MENTION IN THE FORECAST...SO WILL KEEP THE FORECAST DRY.

LOW LEVEL THICKNESSES PROGS GENERALLY SUPPORT THE GFS MOS LOWS
TONIGHT...SO LITTLE ADJUSTMENT TO THE GUIDANCE.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 224 PM EDT SUN MAY 19 2013

MAIN FEATURE DURING THIS PERIOD WILL BE THE LARGE UPPER LOW OVER THE
PLAINS THAT IS EXPECTED TO GRADUALLY OPEN UP AND MOVE INTO THE
MIDWEST BY WEDNESDAY...KEEPING THE SHORT TERM UNSETTLED.

SOME OF THE FINER SCALE MODELS SUGGEST THERE MAY SOME SORT OF
BOUNDARY...POSSIBLY ORIGINATING FROM CONVECTIVE ACTIVITY TO THE
WEST TONIGHT...THAT MAY MOVE INTO THE AREA AROUND MIDDAY ON
MONDAY. AIR MASS IS PROGGED TO BECOME VERY UNSTABLE ON
MONDAY...LI/S DOWN TO ABOUT -8...UNDERNEATH STEEP MID LEVEL LAPSE
RATES. WILL GO WITH CHANCE POPS STARTING AROUND MIDDAY AND ON INTO
THE AFTERNOON.

AFTER MONDAY...DETAILS BECOME A BIT MORE MURKY AS ROUNDS OF
CONVECTION ASSOCIATED WITH THIS SYSTEM MAY TEND TO BLUR THE COLD
FRONT POSITION. MODEL DATA SUGGEST ACTUAL COLD FRONT MAY NOT MOVE
THROUGH UNTIL WEDNESDAY NIGHT OR LATER. MODEL DATA DOES SUGGEST
LAPSE RATES GRADUALLY BECOME POORER WITH TIME AS AIR MASS GETS
WORKED OVER...ALTHOUGH DEEP LAYER SHEAR MAY TEND TO INCREASE SOME
TOWARDS TUESDAY AND WEDNESDAY. AT THIS POINT...CAN/T REALLY PIN DOWN
ANY PERIODS TO CONCENTRATE POPS ON...SO WITH BROADBRUSH HIGH CHANCE
POPS FROM MONDAY NIGHT THROUGH WEDNESDAY.

PROGGED LOW LEVEL THICKNESSES SUGGEST THE GFS MOS HIGHS FOR MONDAY
AND TUESDAY MAY BE A BIT ON THE WARM SIDE...ESPECIALLY WITH THE
POTENTIAL FOR CONVECTION OR ITS REMNANTS AROUND. WILL NUDGE THE
HIGHS DOWN A BIT. LOWS LOOK OK.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 224 PM EDT SUN MAY 19 2013

ECMWF AND GFS BOTH INDICATE A FRONTAL BOUNDARY AND ASSOCIATED UPPER
TROUGH EXITING THE RGN ON WEDNESDAY NIGHT AND EARLY ON THURSDAY. A
STRONG RIDGE ALOFT THEN BUILDS ACROSS THE OHIO VALLEY FOR FRIDAY AND
SATURDAY FROM THE CENTRAL PLAINS ALONG WITH COOLER AND DRY NW FLOW.
THUS WILL KEEP SOME CHCS FOR TSRA ON WEDNESDAY NIGHT AND SHRA ON
THURSDAY IN THE CYCLONIC FLOW ON THURSDAY. HOWEVER DRY WEATHER WILL
BE EXPECTED AS THE WORK WEEK CONCLUDES ON FRIDAY ALONG WITH TEMPS AT
OR ONLY SLIGHTLY ABOVE NORMALS.

ECMWF HINTS AT A WARM FRONT AND A WEAK S/W WAVE PUSHING INTO THE
AREA ON SUNDAY AND FOR NOW HAVE INCLUDED SOME LOW CHC POPS.

&&

.AVIATION /DISCUSSION FOR THE 200000Z TAF ISSUANCE/...

ISSUED AT 645 PM EDT SUN MAY 19 2013

VFR CONDITIONS EXPECTED TONIGHT WITH ONLY HIGH CLOUDS AS DIURNAL CU
DISSIPATES. MODELS SHOWING LINGERING LOW LEVEL MOISTURE...BUT THINK
FOG WILL NOT BE A PROBLEM LIKE LAST NIGHT AS SURFACE PRESSURE
GRADIENT PICKS UP AHEAD OF THE PLAINS FRONTAL SYSTEM WHICH SHOULD
KEEP SOUTH WINDS 5 KNOTS OR MORE. THE EXCEPTION COULD BE AT
BMG...WHERE GRADIENT WILL BE A BIT WEAKER WHICH SHOULD ALLOW SOUTH
WINDS TO DROP BELOW 5 KNOTS. THIS COULD ONCE AGAIN RESULT IN SOME
IFR FOG AT BMG AFTER 08Z THROUGH ABOUT 13Z. WOULD ALSO NOT RULE OUT
SOME LOW STRATUS OVERNIGHT...BUT FOR NOW WILL ONLY GO WITH SCATTERED
LOW STRATUS AT IND AND BMG AFTER 08Z.

WOULD NOT RULE OUT THUNDERSTORMS AFTER 14Z TOMORROW...BUT WITH
COVERAGE EXPECTED TO BE SCATTERED AT BEST AND BEING SO FAR
OUT...WILL HOLD OFF ON VCTS FOR NOW. SHOULD SEE SCATTERED TO BROKEN
DIURNAL VFR CU TOMORROW AFTERNOON. WINDS WILL BE INCREASING TOMORROW
WITH SOUTH AND SOUTHWEST WINDS INCREASING TO AROUND 15 KNOTS WITH
GUSTS TO 23 KNOTS AFTER 14Z.

&&

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

$$

SYNOPSIS...JAS
NEAR TERM...JAS
SHORT TERM...JAS
LONG TERM....PUMA
AVIATION...MK

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

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

000
FXUS63 KIWX 192105
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
505 PM EDT SUN MAY 19 2013

.SYNOPSIS...
ISSUED AT 504 PM EDT SUN MAY 19 2013

SKIES WILL REMAIN MOSTLY CLEAR TO PARTLY CLOUDY TONIGHT...WITH LOW
TEMPERATURES MAINLY IN THE MID 60S. A LOW PRESSURE SYSTEM WILL MAKE
ITS WAY ACROSS THE REGION EARLY THIS WEEK...BRINGING CHANCES FOR
SHOWERS AND THUNDERSTORMS THROUGHOUT THE WEEK. TEMPERATURES ARE
EXPECTED TO BE FAIRLY WARM MONDAY AND TUESDAY BEFORE DROPPING DOWN
TO MORE SEASONABLE LEVELS BY THE END OF THE WEEK.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 320 PM EDT SUN MAY 19 2013

TIGHT DEWPOINT GRADIENT WHICH HAD BEEN EVER PERSISTENT ACROSS OUR
AREA HAS FINALLY BEEN ERRADICATED AS LOW TO MID 60S DEWPOINTS HAVE
NOW OVERSPREAD THE ENTIRE CWA. THIS INCREASE IN SURFACE DEWPOINTS
HAS YIELDED SBCAPE VALUES BETWEEN 1500 AND 2000 J/KG. WITH A LACK OF
ANY SIGNIFICANT FORCING...NOTHING MORE THAN A SCATTERED TO BROKEN CU
DECK HAS BEEN ABLE TO DEVELOP.  THIS CU FIELD WILL DISSIPATE BY
LATE AFTERNOON AS A DEEP EML/CAPPING INVERSION OVERSPREADS THE CWA
FROM THE WEST.

PRECIP POTENTIAL FOR TONIGHT REMAINS COMPLICATED AS SIGNIFICANT
MODEL SPREAD EXISTS REGARDING THE LOCATION AND PERSISTENCE OF
REMNANT CONVECTION FROM IOWA/MISSOURI SEVERE WEATHER TODAY. GLOBAL
MODELS KEEP CONVECTION NORTHWEST OF OUR CWA...WHILE HI
RESOLUTION/CONVECTION ALLOWING MODELS BRING PRECIP INTO AT LEAST THE
WESTERN HALF OF THE CWA AFTER 05Z BEFORE COMPLETELY DISSIPATING.
KEPT SLIGHT CHANCE POPS IN THE NORTHWEST OVERNIGHT WITH THE ONLY
CHANGE BEING A SLIGHTLY EARLIER ARRIVAL TIME AS HRRR GUIDANCE IS
CONSISTENTLY BRINGING CONVECTION INTO WESTERN AREAS BETWEEN 03-04Z.

TEMPS WILL WARM INTO THE UPPER 80S ON MONDAY WITH A FEW LOCATIONS
LIKELY REACHING 90 DEGREES. THESE ABOVE NORMAL TEMPS COUPLED WITH
UPPER 60S TO NEAR 70 DEWPOINTS WILL MAKE THE MONDAY AIRMASS QUITE
UNSTABLE. KEPT POPS IN THE LOW CHANCE RANGE AS UNCERTAINTIES
REGARDING THE STRENGTH OF THE CAP AND ANY CONVECTIVE DEBRIS WHICH
MAY OVERSPREAD THE AREA LIMIT CONFIDENCE. IF CONVECTION CAN
DEVELOP...SEVERE POTENTIAL WILL INCREASE THROUGH TIME AS A 50-60 KT
MID-LEVEL JET STREAK CLIPS THE NORTHWEST PORTION OF OUR FORECAST
AREA NEAR 21Z AND IMPROVES THE SHEAR PROFILE.

&&

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 320 PM EDT SUN MAY 19 2013

FCST PERIOD TO BEGIN WITH SFC LOW AND VERTICALLY STACKED CLOSED
UPPER LOW OVER THE NORTHERN PLAINS/UPPER MIDWEST. BEST FOCUS AND
FORCING FOR CONVECTIVE INITIATION HEADING INTO MONDAY EVENING WILL
BE TO THE WEST OF OUR AREA DESPITE BEING IN A VERY UNSTABLE WARM
SECTOR WITH CAPES AOA 3000J/KG OVER MUCH OF THE CWA. 500MB RIDGE
SHIFTS EAST OF THE AREA MON NITE AND BREAKDOWN OF THICKNESS RIDGE
WILL PROVIDE AN OPPORTUNITY FOR CONVECTION TO WORK INTO THE WESTERN
CWA 06-12Z TUE. GOOD MOISTURE ADVECTION ON A 40-50KT LLJ ALONG WITH
A 50-60KT MID LEVEL SPEED MAX WILL ACCOMPANY SFC PRE-FRONTAL TROF ON
TUE BRINGING GOOD CONVECTIVE POTENTIAL INTO THE AREA. UNCERTAINTY
WILL BE IN ABILITY FOR DESTABILIZATION...PUTTING SEVERE POTENTIAL IN
QUESTION. MAIN SFC FRONT TO FOLLOW ON WED WHICH WILL KEEP LIKELY
POPS FOR SH/TSRA GOING DURING THE DAY. SECONDARY FRONT THEN SET TO
MOVE THRU ON THURSDAY BEFORE ENTIRE SYSTEM FINALLY KICKS EAST OF OUR
AREA AND SETS THE STAGE FOR A COOLER BUT PLEASANT START TO THE
MEMORIAL DAY WEEKEND AS CANADIAN HIGH PRESSURE BUILDS INTO THE GREAT
LAKES REGION ON FRI/SAT. GFS AND ECMWF TRENDING TOWARD A MUCH
DIFFERENT SOLN COMPARED TO EARLIER RUNS FOR THE REST OF THE HOLIDAY
WEEKEND. WHAT WAS ONCE AN AMPLIFIED NW FLOW PATTERN WITH A
RE-ENFORCING DRY CANADIAN AIRMASS IS NOW BEING OFFERED AS A
TRANSITION TO A MORE ZONAL PATTERN AND KICKING SHORTWAVE DISTURBANCE
INTO THE REGION AND A CHANCE FOR PRECIP SUNDAY. NOT EAGER TO BUY
INTO THIS SOLN JUST YET...ESPECIALLY GIVEN THAT EVEN THE HIGHER END
OF THE ENSEMBLE MEMBERS HAVE POPS BELOW CLIMO. THAT AND GIVEN ITS IN
DAY 7 WILL OPT TO CONTINUE WITH DRY FCST FOR NOW AND WAIT TO SEE IF
TREND CONTINUES AND STRONGER SIGNAL IN MODEL GUIDANCE PRESENTS
ITSELF.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 0220
PM EDT SUN MAY 19 2013

SCATTERED TO BROKEN CU FIELD HAS DEVELOPED ACROSS THE AREA THIS
AFTERNOON.  THIS CU FIELD WILL DIMINISH OVER THE NEXT FEW HOURS AS
EML/CAPPING INVERSION ADVECTS INTO THE AREA. THIS CAP WILL KEEP BOTH
TERMINALS DRY DURING THE DAY. THERE IS A CHANCE OF THUNDERSTORMS AT
KSBN AFTER 05Z AS SEVERAL SHORT TERM MODELS INDICATE REMNANT
DISSIPATING CONVECTION FROM THE WEST MOVING ACROSS SOUTHERN LAKE
MICHIGAN. KEPT MENTION VCTS MENTION OUT OF THE 18Z TAF AND WILL
CONTINUE TO MONITOR TRENDS FOR POTENTIAL INCLUSION IN 00Z TAF. ANY
CONVECTION WHICH MAY MOVE INTO THE AREA SHOULD STAY NORTHWEST OF
KFWA.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...KG
SHORT TERM...BENTLEY
LONG TERM...JAL
AVIATION...BENTLEY


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIND 192034
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
430 PM EDT SUN MAY 19 2013

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

&&

.SYNOPSIS...
ISSUED AT 224 PM EDT SUN MAY 19 2013

A LARGE UPPER LOW CURRENTLY OVER THE PLAINS IS EXPECTED TO BRING
UNSETTLED WEATHER TO THE AREA THROUGH THURSDAY AS IT SLOWLY MOVES
EAST AND WEAKENS WITH TIME. HIGH PRESSURE IS EXPECTED TO BUILD IN
BEHIND THIS SYSTEM TOWARDS THE END OF THE WEEK. ANOTHER FRONTAL
SYSTEM MAY APPROACH THE AREA BY NEXT SUNDAY.

&&

.NEAR TERM /TONIGHT/...
ISSUED AT 224 PM EDT SUN MAY 19 2013

MODEL DATA SUGGEST FAIRLY STRONG 850MB WARM ADVECTION WILL BE
DEVELOPING ACROSS THE AREA BY LATE TONIGHT AS A 40-45KT LOW LEVEL
JET IS PROGGED TO NOSE TOWARDS INTO WESTERN INDIANA BY SUNRISE
MONDAY. SOME CONCERN THAT THIS MAY LEAD TO SOME ELEVATED CONVECTION
DURING THE PRE DAWN HOURS OF MONDAY GIVEN THE VERY STEEP MID LEVEL
LAPSE RATES EXPECTED OVER THE AREA. MODELS INDICATE SOME ENHANCED
MOISTURE IN THE PRECIPITATION BEARING LAYER AS WELL. AT THIS
POINT...DON/T THINK COVERAGE/POTENTIAL IS HIGH ENOUGH FOR A
MENTION IN THE FORECAST...SO WILL KEEP THE FORECAST DRY.

LOW LEVEL THICKNESSES PROGS GENERALLY SUPPORT THE GFS MOS LOWS
TONIGHT...SO LITTLE ADJUSTMENT TO THE GUIDANCE.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 224 PM EDT SUN MAY 19 2013

MAIN FEATURE DURING THIS PERIOD WILL BE THE LARGE UPPER LOW OVER THE
PLAINS THAT IS EXPECTED TO GRADUALLY OPEN UP AND MOVE INTO THE
MIDWEST BY WEDNESDAY...KEEPING THE SHORT TERM UNSETTLED.

SOME OF THE FINER SCALE MODELS SUGGEST THERE MAY SOME SORT OF
BOUNDARY...POSSIBLY ORIGINATING FROM CONVECTIVE ACTIVITY TO THE
WEST TONIGHT...THAT MAY MOVE INTO THE AREA AROUND MIDDAY ON
MONDAY. AIR MASS IS PROGGED TO BECOME VERY UNSTABLE ON
MONDAY...LI/S DOWN TO ABOUT -8...UNDERNEATH STEEP MID LEVEL LAPSE
RATES. WILL GO WITH CHANCE POPS STARTING AROUND MIDDAY AND ON INTO
THE AFTERNOON.

AFTER MONDAY...DETAILS BECOME A BIT MORE MURKY AS ROUNDS OF
CONVECTION ASSOCIATED WITH THIS SYSTEM MAY TEND TO BLUR THE COLD
FRONT POSITION. MODEL DATA SUGGEST ACTUAL COLD FRONT MAY NOT MOVE
THROUGH UNTIL WEDNESDAY NIGHT OR LATER. MODEL DATA DOES SUGGEST
LAPSE RATES GRADUALLY BECOME POORER WITH TIME AS AIR MASS GETS
WORKED OVER...ALTHOUGH DEEP LAYER SHEAR MAY TEND TO INCREASE SOME
TOWARDS TUESDAY AND WEDNESDAY. AT THIS POINT...CAN/T REALLY PIN DOWN
ANY PERIODS TO CONCENTRATE POPS ON...SO WITH BROADBRUSH HIGH CHANCE
POPS FROM MONDAY NIGHT THROUGH WEDNESDAY.

PROGGED LOW LEVEL THICKNESSES SUGGEST THE GFS MOS HIGHS FOR MONDAY
AND TUESDAY MAY BE A BIT ON THE WARM SIDE...ESPECIALLY WITH THE
POTENTIAL FOR CONVECTION OR ITS REMNANTS AROUND. WILL NUDGE THE
HIGHS DOWN A BIT. LOWS LOOK OK.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 224 PM EDT SUN MAY 19 2013

ECMWF AND GFS BOTH INDICATE A FRONTAL BOUNDARY AND ASSOCIATED UPPER
TROUGH EXITING THE RGN ON WEDNESDAY NIGHT AND EARLY ON THURSDAY. A
STRONG RIDGE ALOFT THEN BUILDS ACROSS THE OHIO VALLEY FOR FRIDAY AND
SATURDAY FROM THE CENTRAL PLAINS ALONG WITH COOLER AND DRY NW FLOW.
THUS WILL KEEP SOME CHCS FOR TSRA ON WEDNESDAY NIGHT AND SHRA ON
THURSDAY IN THE CYCLONIC FLOW ON THURSDAY. HOWEVER DRY WEATHER WILL
BE EXPECTED AS THE WORK WEEK CONCLUDES ON FRIDAY ALONG WITH TEMPS AT
OR ONLY SLIGHTLY ABOVE NORMALS.

ECMWF HINTS AT A WARM FRONT AND A WEAK S/W WAVE PUSHING INTO THE
AREA ON SUNDAY AND FOR NOW HAVE INCLUDED SOME LOW CHC POPS.

&&

.AVIATION /DISCUSSION FOR THE 192100Z IND TAF UPDATE/...

ISSUED AT 430 PM EDT SUN MAY 19 2013

RAISED WINDS TO 9 KNOTS PER TRENDS...OTHERWISE NO CHANGES.

PREVIOUS DISCUSSION FOLLOWS...

VFR CONDITIONS WILL BE EXPECTED THE NEXT 12 HOURS. SOME MVFR OR
IFR VISIBILITIES WILL BE POSSIBLE OVERNIGHT DUE TO DIURNAL FOG. A
RETURN TO VFR IS EXPECTED QUICKLY BY 14Z MONDAY AS HEATING AND
MIXING RESUMES.

A WARM AND MOIST AIR MASS REMAINS IN PLACE ACROSS CENTRAL INDIANA
TODAY WITH DEW POINTS IN THE MIDDLE 60S. CONVECTIVE TEMPERATURES
WILL BE REACHED THIS AFTERNOON AND CU RULE SUGGESTS SCT CU. WITH
CCLS NEAR 3500 FT...ANY BRIEF CIGS WILL BE VFR.

AFTER HEATING IS LOST...EXPECTED CLEARING SKIES. HOWEVER WITH
LIGHT WINDS AND HIGH DEW POINTS IN THE AREA ALONG WITH LITTLE
CHANGE IN THE OVERALL AIRMASS FROM THE PAST FEW DAYS...HAVE
TRENDED TOWARD SOME PERSISTENCE TYPE FOG OVERNIGHT. AGAIN, ONCE
HEATING RESUMES ON MONDAY MORNING...DIURNAL FOG WILL QUICKLY BURN
OFF.


&&

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

$$

SYNOPSIS...JAS
NEAR TERM...JAS
SHORT TERM...JAS
LONG TERM....PUMA
AVIATION...JP/MK

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

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

000
FXUS63 KIWX 191922
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
322 PM EDT SUN MAY 19 2013

.SYNOPSIS...
ISSUED AT 1049 AM EDT SUN MAY 19 2013

HIGH PRESSURE CENTERED OFF OF THE NEW ENGLAND COAST WILL PROVIDE
SUNNY DRY WEATHER FOR TODAY. SOME CLOUDS FROM A LOW PRESSURE
SYSTEM IN THE CENTRAL PART OF THE COUNTRY WILL MOVE THROUGH TODAY
WITH TEMPERATURES ABOVE NORMAL. THAT LOW PRESSURE SYSTEM WILL MOVE
IN AND THROUGH THE REGION THROUGH THIS WEEK PROVIDING SHOWER AND
THUNDERSTORM CHANCES. TEMPERATURES THROUGH THE WEEK WILL GRADUALLY
COOL OFF AND BECOME MORE NORMAL BY WEEKS END.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 320 PM EDT SUN MAY 19 2013

TIGHT DEWPOINT GRADIENT WHICH HAD BEEN EVER PERSISTENT ACROSS OUR
AREA HAS FINALLY BEEN ERRADICATED AS LOW TO MID 60S DEWPOINTS HAVE
NOW OVERSPREAD THE ENTIRE CWA. THIS INCREASE IN SURFACE DEWPOINTS
HAS YIELDED SBCAPE VALUES BETWEEN 1500 AND 2000 J/KG. WITH A LACK OF
ANY SIGNIFICANT FORCING...NOTHING MORE THAN A SCATTERED TO BROKEN CU
DECK HAS BEEN ABLE TO DEVELOP.  THIS CU FIELD WILL DISSIPATE BY
LATE AFTERNOON AS A DEEP EML/CAPPING INVERSION OVERSPREADS THE CWA
FROM THE WEST.

PRECIP POTENTIAL FOR TONIGHT REMAINS COMPLICATED AS SIGNIFICANT
MODEL SPREAD EXISTS REGARDING THE LOCATION AND PERSISTENCE OF
REMNANT CONVECTION FROM IOWA/MISSOURI SEVERE WEATHER TODAY. GLOBAL
MODELS KEEP CONVECTION NORTHWEST OF OUR CWA...WHILE HI
RESOLUTION/CONVECTION ALLOWING MODELS BRING PRECIP INTO AT LEAST THE
WESTERN HALF OF THE CWA AFTER 05Z BEFORE COMPLETELY DISSIPATING.
KEPT SLIGHT CHANCE POPS IN THE NORTHWEST OVERNIGHT WITH THE ONLY
CHANGE BEING A SLIGHTLY EARLIER ARRIVAL TIME AS HRRR GUIDANCE IS
CONSISTENTLY BRINGING CONVECTION INTO WESTERN AREAS BETWEEN 03-04Z.

TEMPS WILL WARM INTO THE UPPER 80S ON MONDAY WITH A FEW LOCATIONS
LIKELY REACHING 90 DEGREES. THESE ABOVE NORMAL TEMPS COUPLED WITH
UPPER 60S TO NEAR 70 DEWPOINTS WILL MAKE THE MONDAY AIRMASS QUITE
UNSTABLE. KEPT POPS IN THE LOW CHANCE RANGE AS UNCERTAINTIES
REGARDING THE STRENGTH OF THE CAP AND ANY CONVECTIVE DEBRIS WHICH
MAY OVERSPREAD THE AREA LIMIT CONFIDENCE. IF CONVECTION CAN
DEVELOP...SEVERE POTENTIAL WILL INCREASE THROUGH TIME AS A 50-60 KT
MID-LEVEL JET STREAK CLIPS THE NORTHWEST PORTION OF OUR FORECAST
AREA NEAR 21Z AND IMPROVES THE SHEAR PROFILE.

&&

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 320 PM EDT SUN MAY 19 2013

FCST PERIOD TO BEGIN WITH SFC LOW AND VERTICALLY STACKED CLOSED
UPPER LOW OVER THE NORTHERN PLAINS/UPPER MIDWEST. BEST FOCUS AND
FORCING FOR CONVECTIVE INITIATION HEADING INTO MONDAY EVENING WILL
BE TO THE WEST OF OUR AREA DESPITE BEING IN A VERY UNSTABLE WARM
SECTOR WITH CAPES AOA 3000J/KG OVER MUCH OF THE CWA. 500MB RIDGE
SHIFTS EAST OF THE AREA MON NITE AND BREAKDOWN OF THICKNESS RIDGE
WILL PROVIDE AN OPPORTUNITY FOR CONVECTION TO WORK INTO THE WESTERN
CWA 06-12Z TUE. GOOD MOISTURE ADVECTION ON A 40-50KT LLJ ALONG WITH
A 50-60KT MID LEVEL SPEED MAX WILL ACCOMPANY SFC PRE-FRONTAL TROF ON
TUE BRINGING GOOD CONVECTIVE POTENTIAL INTO THE AREA. UNCERTAINTY
WILL BE IN ABILITY FOR DESTABILIZATION...PUTTING SEVERE POTENTIAL IN
QUESTION. MAIN SFC FRONT TO FOLLOW ON WED WHICH WILL KEEP LIKELY
POPS FOR SH/TSRA GOING DURING THE DAY. SECONDARY FRONT THEN SET TO
MOVE THRU ON THURSDAY BEFORE ENTIRE SYSTEM FINALLY KICKS EAST OF OUR
AREA AND SETS THE STAGE FOR A COOLER BUT PLEASANT START TO THE
MEMORIAL DAY WEEKEND AS CANADIAN HIGH PRESSURE BUILDS INTO THE GREAT
LAKES REGION ON FRI/SAT. GFS AND ECMWF TRENDING TOWARD A MUCH
DIFFERENT SOLN COMPARED TO EARLIER RUNS FOR THE REST OF THE HOLIDAY
WEEKEND. WHAT WAS ONCE AN AMPLIFIED NW FLOW PATTERN WITH A
RE-ENFORCING DRY CANADIAN AIRMASS IS NOW BEING OFFERED AS A
TRANSITION TO A MORE ZONAL PATTERN AND KICKING SHORTWAVE DISTURBANCE
INTO THE REGION AND A CHANCE FOR PRECIP SUNDAY. NOT EAGER TO BUY
INTO THIS SOLN JUST YET...ESPECIALLY GIVEN THAT EVEN THE HIGHER END
OF THE ENSEMBLE MEMBERS HAVE POPS BELOW CLIMO. THAT AND GIVEN ITS IN
DAY 7 WILL OPT TO CONTINUE WITH DRY FCST FOR NOW AND WAIT TO SEE IF
TREND CONTINUES AND STRONGER SIGNAL IN MODEL GUIDANCE PRESENTS
ITSELF.


&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 0220
PM EDT SUN MAY 19 2013

SCATTERED TO BROKEN CU FIELD HAS DEVELOPED ACROSS THE AREA THIS
AFTERNOON.  THIS CU FIELD WILL DIMINISH OVER THE NEXT FEW HOURS AS
EML/CAPPING INVERSION ADVECTS INTO THE AREA. THIS CAP WILL KEEP BOTH
TERMINALS DRY DURING THE DAY. THERE IS A CHANCE OF THUNDERSTORMS AT
KSBN AFTER 05Z AS SEVERAL SHORT TERM MODELS INDICATE REMNANT
DISSIPATING CONVECTION FROM THE WEST MOVING ACROSS SOUTHERN LAKE
MICHIGAN. KEPT MENTION VCTS MENTION OUT OF THE 18Z TAF AND WILL
CONTINUE TO MONITOR TRENDS FOR POTENTIAL INCLUSION IN 00Z TAF. ANY
CONVECTION WHICH MAY MOVE INTO THE AREA SHOULD STAY NORTHWEST OF
KFWA.



&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...LOTHAMER
SHORT TERM...BENTLEY
LONG TERM...JAL
AVIATION...BENTLEY


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIND 191829
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
229 PM EDT SUN MAY 19 2013

.UPDATE...
THE SYNOPSIS...NEAR TERM...SHORT TERM AND LONG TERM SECTIONS HAVE
BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 224 PM EDT SUN MAY 19 2013

A LARGE UPPER LOW CURRENTLY OVER THE PLAINS IS EXPECTED TO BRING
UNSETTLED WEATHER TO THE AREA THROUGH THURSDAY AS IT SLOWLY MOVES
EAST AND WEAKENS WITH TIME. HIGH PRESSURE IS EXPECTED TO BUILD IN
BEHIND THIS SYSTEM TOWARDS THE END OF THE WEEK. ANOTHER FRONTAL
SYSTEM MAY APPROACH THE AREA BY NEXT SUNDAY.

&&

.NEAR TERM /TONIGHT/...
ISSUED AT 224 PM EDT SUN MAY 19 2013

MODEL DATA SUGGEST FAIRLY STRONG 850MB WARM ADVECTION WILL BE
DEVELOPING ACROSS THE AREA BY LATE TONIGHT AS A 40-45KT LOW LEVEL
JET IS PROGGED TO NOSE TOWARDS INTO WESTERN INDIANA BY SUNRISE
MONDAY. SOME CONCERN THAT THIS MAY LEAD TO SOME ELEVATED CONVECTION
DURING THE PRE DAWN HOURS OF MONDAY GIVEN THE VERY STEEP MID LEVEL
LAPSE RATES EXPECTED OVER THE AREA. MODELS INDICATE SOME ENHANCED
MOISTURE IN THE PRECIPITATION BEARING LAYER AS WELL. AT THIS
POINT...DON/T THINK COVERAGE/POTENTIAL IS HIGH ENOUGH FOR A
MENTION IN THE FORECAST...SO WILL KEEP THE FORECAST DRY.

LOW LEVEL THICKNESSES PROGS GENERALLY SUPPORT THE GFS MOS LOWS
TONIGHT...SO LITTLE ADJUSTMENT TO THE GUIDANCE.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 224 PM EDT SUN MAY 19 2013

MAIN FEATURE DURING THIS PERIOD WILL BE THE LARGE UPPER LOW OVER THE
PLAINS THAT IS EXPECTED TO GRADUALLY OPEN UP AND MOVE INTO THE
MIDWEST BY WEDNESDAY...KEEPING THE SHORT TERM UNSETTLED.

SOME OF THE FINER SCALE MODELS SUGGEST THERE MAY SOME SORT OF
BOUNDARY...POSSIBLY ORIGINATING FROM CONVECTIVE ACTIVITY TO THE
WEST TONIGHT...THAT MAY MOVE INTO THE AREA AROUND MIDDAY ON
MONDAY. AIR MASS IS PROGGED TO BECOME VERY UNSTABLE ON
MONDAY...LI/S DOWN TO ABOUT -8...UNDERNEATH STEEP MID LEVEL LAPSE
RATES. WILL GO WITH CHANCE POPS STARTING AROUND MIDDAY AND ON INTO
THE AFTERNOON.

AFTER MONDAY...DETAILS BECOME A BIT MORE MURKY AS ROUNDS OF
CONVECTION ASSOCIATED WITH THIS SYSTEM MAY TEND TO BLUR THE COLD
FRONT POSITION. MODEL DATA SUGGEST ACTUAL COLD FRONT MAY NOT MOVE
THROUGH UNTIL WEDNESDAY NIGHT OR LATER. MODEL DATA DOES SUGGEST
LAPSE RATES GRADUALLY BECOME POORER WITH TIME AS AIR MASS GETS
WORKED OVER...ALTHOUGH DEEP LAYER SHEAR MAY TEND TO INCREASE SOME
TOWARDS TUESDAY AND WEDNESDAY. AT THIS POINT...CAN/T REALLY PIN DOWN
ANY PERIODS TO CONCENTRATE POPS ON...SO WITH BROADBRUSH HIGH CHANCE
POPS FROM MONDAY NIGHT THROUGH WEDNESDAY.

PROGGED LOW LEVEL THICKNESSES SUGGEST THE GFS MOS HIGHS FOR MONDAY
AND TUESDAY MAY BE A BIT ON THE WARM SIDE...ESPECIALLY WITH THE
POTENTIAL FOR CONVECTION OR ITS REMNANTS AROUND. WILL NUDGE THE
HIGHS DOWN A BIT. LOWS LOOK OK.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 224 PM EDT SUN MAY 19 2013

ECMWF AND GFS BOTH INDICATE A FRONTAL BOUNDARY AND ASSOCIATED UPPER
TROUGH EXITING THE RGN ON WEDNESDAY NIGHT AND EARLY ON THURSDAY. A
STRONG RIDGE ALOFT THEN BUILDS ACROSS THE OHIO VALLEY FOR FRIDAY AND
SATURDAY FROM THE CENTRAL PLAINS ALONG WITH COOLER AND DRY NW FLOW.
THUS WILL KEEP SOME CHCS FOR TSRA ON WEDNESDAY NIGHT AND SHRA ON
THURSDAY IN THE CYCLONIC FLOW ON THURSDAY. HOWEVER DRY WEATHER WILL
BE EXPECTED AS THE WORK WEEK CONCLUDES ON FRIDAY ALONG WITH TEMPS AT
OR ONLY SLIGHTLY ABOVE NORMALS.

ECMWF HINTS AT A WARM FRONT AND A WEAK S/W WAVE PUSHING INTO THE
AREA ON SUNDAY AND FOR NOW HAVE INCLUDED SOME LOW CHC POPS.

&&

.AVIATION /DISCUSSION FOR THE 191800Z TAFS/...

ISSUED AT 1219 PM EDT SUN MAY 19 2013

VFR CONDITIONS WILL BE EXPECTED THE NEXT 12 HOURS. SOME MVFR OR
IFR VISIBILITIES WILL BE POSSIBLE OVERNIGHT DUE TO DIURNAL FOG. A
RETURN TO VFR IS EXPECTED QUICKLY BY 14Z MONDAY AS HEATING AND
MIXING RESUMES.

A WARM AND MOIST AIR MASS REMAINS IN PLACE ACROSS CENTRAL INDIANA
TODAY WITH DEW POINTS IN THE MIDDLE 60S. CONVECTIVE TEMPERATURES
WILL BE REACHED THIS AFTERNOON AND CU RULE SUGGESTS SCT CU. WITH
CCLS NEAR 3500 FT...ANY BRIEF CIGS WILL BE VFR.

AFTER HEATING IS LOST...EXPECTED CLEARING SKIES. HOWEVER WITH
LIGHT WINDS AND HIGH DEW POINTS IN THE AREA ALONG WITH LITTLE
CHANGE IN THE OVERALL AIRMASS FROM THE PAST FEW DAYS...HAVE
TRENDED TOWARD SOME PERSISTENCE TYPE FOG OVERNIGHT. AGAIN, ONCE
HEATING RESUMES ON MONDAY MORNING...DIURNAL FOG WILL QUICKLY BURN
OFF.


&&

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

$$

SYNOPSIS...JAS
NEAR TERM...JAS
SHORT TERM...JAS
LONG TERM....PUMA
AVIATION...JP

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

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

000
FXUS63 KIWX 191724
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
124 PM EDT SUN MAY 19 2013

.SYNOPSIS...
ISSUED AT 1049 AM EDT SUN MAY 19 2013

HIGH PRESSURE CENTERED OFF OF THE NEW ENGLAND COAST WILL PROVIDE
SUNNY DRY WEATHER FOR TODAY. SOME CLOUDS FROM A LOW PRESSURE
SYSTEM IN THE CENTRAL PART OF THE COUNTRY WILL MOVE THROUGH TODAY
WITH TEMPERATURES ABOVE NORMAL. THAT LOW PRESSURE SYSTEM WILL MOVE
IN AND THROUGH THE REGION THROUGH THIS WEEK PROVIDING SHOWER AND
THUNDERSTORM CHANCES. TEMPERATURES THROUGH THE WEEK WILL GRADUALLY
COOL OFF AND BECOME MORE NORMAL BY WEEKS END.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 503 AM EDT SUN MAY 19 2013

AN UPPER LOW SOUTH OF THE AREA WILL EJECT EAST OUT OF THE REGION
TODAY. IN ITS WAKE...A LINGERING SURFACE DEW POINT GRADIENT WAS
STILL OVER THE AREA...BUT NOT AS PRONOUNCED AS THE LAST COUPLE OF
NIGHTS. CONCERN WITH DAYTIME HEATING AND AFTERNOON/EARLY EVENING
CAPES TOPPING 3000 J/KG PER NAM BUF/KIT OVER SOUTHWEST AREAS.
HOWEVER... THE ENVIRONMENT WILL REMAIN VERY LIGHTLY SHEARED WITH
REALLY NOTHING TO FOCUS OR FORCE CONVECTION...OTHER THAN THE
MODIFYING DEW POINT BOUNDARY. FOR NOW...KEPT SHOWERS/STORMS OUT OF
THE FCST TODAY. KEPT A LOW CHANCE FOR SHOWERS/STORMS TONIGHT OVER NW
AREAS WITH THE APPROACH OF AN EMBEDDED SHORT WAVE TROF IN THE
APPROACHING LONG WAVE TROF...AND ALSO IN THE VICINITY OF AN AREAS OF
LOW LEVEL THETA E CONVERGENCE. OTHERWISE...KEPT HIGHS TODAY ABOVE
EVEN THE WARMER GFS/MAV WITH 850 MB TEMPS PUSHING 17C WITH
INCREASING UPPER LEVEL SUBSIDENCE.

&&

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 503 AM EDT SUN MAY 19 2013

NEGATIVELY TILTED LONGWAVE TROUGH CURRENTLY OVER THE ROCKY MOUNTAINS
WILL FULLY TRANSITION TO AN EXPANSIVE CLOSED LOW BY MONDAY AND WILL
BRING INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS IN OUR AREA
THROUGH MIDWEEK AS IT VERY SLOWLY PROGRESSES EASTWARD. PRECIP
CHANCES ON MONDAY STILL A BIT OF A QUESTION MARK THOUGH. SURFACE
FRONTAL BOUNDARY WILL BE WELL NORTH OF HERE BY MONDAY AFTERNOON WITH
GOOD SOUTHWEST FLOW PUSHING 850MB TEMPS TO AROUND 19C. MIXING THIS
TO THE SURFACE YIELDS AFTERNOON TEMPS APPROACHING 90F...IN LINE WITH
A CONSENSUS OF LATEST MOS GUIDANCE. NOT UNHEARD OF TO REACH 90F THIS
EARLY BUT CERTAINLY NOT COMMON. SURFACE DEWPOINTS WILL ALSO BE
CREEPING INTO THE MID AND PERHAPS UPPER 60S. 70F DEWPOINTS SEEN IN
RAW GUIDANCE LIKELY A BIT OVERZEALOUS BUT MODIFIED SOUNDINGS STILL
SHOW A HEALTHY AMOUNT OF CONDITIONAL INSTABILITY. QUESTION CONTINUES
TO BE HOW STRONG THE CAP WILL BE OVER OUR AREA. SOUTHERN GREAT LAKES
CONTINUE TO BE LARGELY UNDER THE INFLUENCE OF MIDLEVEL RIDGING ON
MONDAY AND THE ASSOCIATED ANTICYCLONIC VORTICITY SHOULD FAVOR A
DECENT SUBSIDENCE INVERSION...AT LEAST EARLY IN THE DAY. POTENTIAL
EXISTS FOR MIDLEVEL HEIGHT FALLS TO PUSH FAR ENOUGH EAST BY LATE IN
THE DAY TO ALLOW FOR CONVECTIVE INITIATION AND DOWNSTREAM
PROPAGATION...AS SEEN IN NEWEST 00Z NAM...BUT STILL FEEL THAT
LARGELY CUTOFF NATURE TO UPSTREAM HEIGHT ANOMALY FAVORS SLOWER
PROGRESSION SEEN IN THE LATEST GFS SOLUTION. WILL THEREFORE MAINTAIN
RELATIVELY LOW POPS DURING THE DAY WITH THE BEST CHANCE ACROSS THE
NORTHWEST DURING THE LATE AFTERNOON/EARLY EVENING. CHANCES INCREASE
POST 00Z AS DECAYING CONVECTION EVENTUALLY SPREADS EAST BUT LACK OF
GOOD SYNOPTIC FORCING MAY LIMIT COVERAGE/AMOUNTS AFTER THE LOSS OF
DAYTIME HEATING. SEVERE WEATHER REMAINS POSSIBLE IF CONVECTION
ARRIVES EARLY ENOUGH. SHEAR VALUES ARE LESS THAN STELLAR BUT DO
INCREASE IN THE WEST BY THE END OF THE DAY. THIS COUPLED WITH GOOD
DIURNALLY DRIVEN INSTABILITY WARRANTS CONTINUED CONDITIONAL THREAT.

PRECIP CHANCES/COVERAGE WILL INCREASE HEADING INTO TUES AND WED AS
THE VERTICALLY STACKED LOW GRADUALLY APPROACHES THE GREAT LAKES.
BROAD WARM/MOIST AIR ADVECTION WILL SUPPORT WIDESPREAD SHOWERS AND
THUNDERSTORMS ACROSS THE ENTIRE REGION. ALSO EXPECT SEVERAL MIDLEVEL
WAVES TO RIPPLE THROUGH THE REGION AND ENHANCE PRECIP
COVERAGE/INTENSITY BUT EXACT TIMING AND LOCATION WILL DEPEND ON
MESOSCALE DETAILS IMPOSSIBLE TO RESOLVE AT THIS TIME RANGE. TIMING
OF THESE MESOSCALE FEATURES WILL ALSO IMPACT OUR SEVERE WEATHER
CHANCES. ANY BREAK IN PRECIP ON TUESDAY COULD ALLOW FOR ENOUGH
DIURNAL INSTABILITY TO SUPPORT SEVERE WEATHER GIVEN DECENT WIND
PROFILES BUT FORECAST SOUNDINGS SHOW INCREASINGLY MOIST ADIABATIC
LAPSE RATES THAT WILL LIKELY INHIBIT OUR SEVERE CHANCES...ESPECIALLY
BY WEDNESDAY. SIGNIFICANT DISAGREEMENT BETWEEN ECMWF AND GFS ON HOW
QUICKLY UPPER LOW GETS REABSORBED INTO MEAN FLOW. THIS WILL HAVE A
LARGE IMPACT ON PRECIP CHANCES THURSDAY BUT EXPECT THERE WILL BE AT
LEAST SOME RESIDUAL SHOWERS IN THE WAKE OF DEPARTING LOW. NORTHWEST
FLOW WILL RETURN BY FRIDAY WITH COOL AND DRY CONDITIONS EXPECTED FOR
AT LEAST THE FIRST HALF OF THE WEEKEND.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 123 PM EDT SUN MAY 19 2013

(FOR THE 18Z TAFS THROUGH 18Z SUNDAY NIGHT) ISSUED AT
0220 PM EDT SUN MAY 19 2013

SCATTERED TO BROKEN CU FIELD HAS DEVELOPED ACROSS THE AREA THIS
AFTERNOON.  THIS CU FIELD WILL DIMINISH OVER THE NEXT FEW HOURS AS
EML/CAPPING INVERSION ADVECTS INTO THE AREA. THIS CAP WILL KEEP BOTH
TERMINALS DRY DURING THE DAY. THERE IS A CHANCE OF THUNDERSTORMS AT
KSBN AFTER 05Z AS SEVERAL SHORT TERM MODELS INDICATE REMNANT
DISSIPATING CONVECTION FROM THE WEST MOVING ACROSS SOUTHERN LAKE
MICHIGAN. KEPT MENTION VCTS MENTION OUT OF THE 18Z TAF AND WILL
CONTINUE TO MONITOR TRENDS FOR POTENTIAL INCLUSION IN 00Z TAF. ANY
CONVECTION WHICH MAY MOVE INTO THE AREA SHOULD STAY NORTHWEST OF
KFWA.



&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...LOTHAMER
SHORT TERM...SKIPPER
LONG TERM...AGD
AVIATION...BENTLEY


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIND 191628
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1228 PM EDT SUN MAY 19 2013

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

&&

.SYNOPSIS...
ISSUED AT 307 AM EDT SUN MAY 19 2013

A WEAK RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE AREA
TODAY...KEEPING DRY AND WARM WEATHER ACROSS CENTRAL INDIANA THROUGH
THE BEGINNING OF THE WORK WEEK. A FEW STORMY DAYS ARE POSSIBLE
DURING THE MIDDLE OF THE WEEK AS A STRONGER AREA OF LOW PRESSURE
DEVELOPS OVER THE PLAINS STATES AND ALLOWS MORE FAVORABLE CONDITIONS
FOR STORMS ACROSS INDIANA.

&&

.NEAR TERM /REST OF TODAY/...
ISSUED AT 1022 AM EDT SUN MAY 19 2013

AREAS OF FOG LINGERING OVER SOME OF THE EAST CENTRAL ZONES AT THIS
TIME...BUT SATELLITE INDICATES RAPID IMPROVEMENT IN THESE AREAS OVER
THE NEXT HOUR OR SO.

OTHERWISE...CONVECTIVE TEMPERATURES REMAIN RATHER LOW TODAY...BUT
NEAR TERM MODEL SOUNDINGS SUGGEST AIR MASS WILL BECOME INCREASINGLY
CAPPED OFF AS THE DAY GOES BY. AS A RESULT...THERE SHOULD BE QUITE A
BIT OF DIURNAL CLOUDS DEVELOP...BUT THINK CHANCES OF CONVECTION WILL
REMAIN LOW. WILL KEEP THE SMALL CHANCE POP OVER THE FAR EAST/SOUTHEAST
THIS AFTERNOON CLOSEST TO REMNANT UPPER LOW.

THIS MORNING/S UPPER AIR SUGGEST HIGHS TODAY MAY A LITTLE
WARM...HOWEVER CURRENT TEMPERATURES RUNNING A LITTLE HIGHER THAN
WHAT WAS EXPECTED BY THIS TIME...SO WILL LEAVE THE HIGHS ALONE.

PREVIOUS DISCUSSION FOLLOWS.

PATCHY FOG WILL HAS ALREADY BEGUN TO FORM WITH A MOIST AIRMASS AND
SOME CLEARING THIS MORNING. BEST CHANCES FOR FOG WILL BE IN AREAS
THAT SAW RAIN YESTERDAY. HAVE ADDED PATCHY FOG TO THE FORECAST AND
THE HAZARDOUS WEATHER OUTLOOK WITH AREAS OF FOG WHERE VISIBILITIES
ARE INDICATING LESS THAN A MILE ACROSS THE SOUTHERN TIER OF
COUNTIES.

MODELS ARE SHOWING LIGHT SHOWERS POSSIBLY DEVELOPING ACROSS THE FAR
EASTERN TIER OF COUNTIES LATE THIS MORNING AND THROUGH THE
AFTERNOON. HAVE ADDED A SLIGHT CHANCE FOR THIS AREA DURING THIS TIME
AS NOT NOT VERY CONFIDENT SHOWERS AND/OR THUNDERSTORMS WILL MAKE IT
THIS FAR WEST WITH A RIDGE BUILDING IN.

TEMPERATURES ON THE WARM SIDE TODAY WITH HIGHS AVERAGING IN THE MID
80S. DID NOT STRAY FAR FROM MOS FOR HIGHS.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
ISSUED AT 307 AM EDT SUN MAY 19 2013

STARTING TONIGHT LEANED CLOSER TO WARMER MAV GUIDANCE FOR
TEMPERATURES AS GOOD WARM AIR ADVECTION WILL BE IN PLACE (ESPECIALLY
FOR MONDAY). A DRY FORECAST WILL GENERALLY PREVAIL UNTIL POSSIBLY
LATE MONDAY AFTERNOON WHEN A DEVELOPING LOW OVER THE CENTRAL PLAINS
MOVES INTO THE AREA.

MODELS SHOW A STRONG UPPER LOW MOVING TOWARD INDIANA LATE MONDAY
NIGHT INTO TUESDAY. AN ALREADY WARM AND MOIST AIR MASS COMBINED WITH
A DEVELOPING FRONTAL BOUNDARY ACROSS THE AREA...AND AN UPPER LOW
MOVING TOWARD THE AREA EJECTING S/WV TOWARDS THE AREA SHOULD PROVIDE
MANY SOURCES FOR CONVECTIVE INITIATION. INDICES FOR TUESDAY AND
TUESDAY NIGHT INDICATE THAT SEVERE WEATHER MAY OCCUR.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
ISSUED AT 229 AM EDT SUN MAY 19 2013

CONTINUE TO EXPECT AN ACTIVE PERIOD THROUGH THE LATTER PART OF THE
COMING WEEK AS A LOW PRESSURE SYSTEM MOVES EXTREMELY SLOWLY OUT
OF THE UPPER MIDWEST AND INTO THE MID ATLANTIC STATES BY THE END
OF THE WEEK. ON THIS...LONG TERM GUIDANCE IS IN GOOD AGREEMENT AND
INITIALIZATION HANDLED WELL.

VERY LATE IN THE PERIOD...INTO THE HOLIDAY WEEKEND...GFS KEEPS A
BROAD SURFACE RIDGE OVER THE AREA...AND EURO DOES TO AN EXTENT AS
WELL...BUT EURO IS MUCH MORE BULLISH ABOUT DEVELOPING PRECIP AND
MOVING IT INTO THE AREA LATE IN THE PERIOD. HAVE A HARD TIME
BUYING THIS WITH SURFACE RIDGING STILL IN THE AREA AND MUCH OF THE
PRECIP DEVELOPING DIRECTLY UNDER AN UPPER LEVEL RIDGE. WILL REMOVE
POPS FROM LATE IN THE PERIOD AND CONTINUE WITH A DRY FORECAST
BEYOND FRIDAY.

TEMPS WERE INITIALIZED FAIRLY WELL AND ONLY REQUIRED MINOR TWEAKS.

&&

.AVIATION /DISCUSSION FOR THE 191800Z TAFS/...

ISSUED AT 1219 PM EDT SUN MAY 19 2013

VFR CONDITIONS WILL BE EXPECTED THE NEXT 12 HOURS. SOME MVFR OR
IFR VISIBILITIES WILL BE POSSIBLE OVERNIGHT DUE TO DIURNAL FOG. A
RETURN TO VFR IS EXPECTED QUICKLY BY 14Z MONDAY AS HEATING AND
MIXING RESUMES.

A WARM AND MOIST AIR MASS REMAINS IN PLACE ACROSS CENTRAL INDIANA
TODAY WITH DEW POINTS IN THE MIDDLE 60S. CONVECTIVE TEMPERATURES
WILL BE REACHED THIS AFTERNOON AND CU RULE SUGGESTS SCT CU. WITH
CCLS NEAR 3500 FT...ANY BRIEF CIGS WILL BE VFR.

AFTER HEATING IS LOST...EXPECTED CLEARING SKIES. HOWEVER WITH
LIGHT WINDS AND HIGH DEW POINTS IN THE AREA ALONG WITH LITTLE
CHANGE IN THE OVERALL AIRMASS FROM THE PAST FEW DAYS...HAVE
TRENDED TOWARD SOME PERSISTENCE TYPE FOG OVERNIGHT. AGAIN, ONCE
HEATING RESUMES ON MONDAY MORNING...DIURNAL FOG WILL QUICKLY BURN
OFF.


&&

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

$$

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

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

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

000
FXUS63 KIWX 191458
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1058 AM EDT SUN MAY 19 2013

.SYNOPSIS...
ISSUED AT 1049 AM EDT SUN MAY 19 2013

HIGH PRESSURE CENTERED OFF OF THE NEW ENGLAND COAST WILL PROVIDE
SUNNY DRY WEATHER FOR TODAY. SOME CLOUDS FROM A LOW PRESSURE
SYSTEM IN THE CENTRAL PART OF THE COUNTRY WILL MOVE THROUGH TODAY
WITH TEMPERATURES ABOVE NORMAL. THAT LOW PRESSURE SYSTEM WILL MOVE
IN AND THROUGH THE REGION THROUGH THIS WEEK PROVIDING SHOWER AND
THUNDERSTORM CHANCES. TEMPERATURES THROUGH THE WEEK WILL GRADUALLY
COOL OFF AND BECOME MORE NORMAL BY WEEKS END.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 503 AM EDT SUN MAY 19 2013

AN UPPER LOW SOUTH OF THE AREA WILL EJECT EAST OUT OF THE REGION
TODAY. IN ITS WAKE...A LINGERING SURFACE DEW POINT GRADIENT WAS
STILL OVER THE AREA...BUT NOT AS PRONOUNCED AS THE LAST COUPLE OF
NIGHTS. CONCERN WITH DAYTIME HEATING AND AFTERNOON/EARLY EVENING
CAPES TOPPING 3000 J/KG PER NAM BUF/KIT OVER SOUTHWEST AREAS.
HOWEVER... THE ENVIRONMENT WILL REMAIN VERY LIGHTLY SHEARED WITH
REALLY NOTHING TO FOCUS OR FORCE CONVECTION...OTHER THAN THE
MODIFYING DEW POINT BOUNDARY. FOR NOW...KEPT SHOWERS/STORMS OUT OF
THE FCST TODAY. KEPT A LOW CHANCE FOR SHOWERS/STORMS TONIGHT OVER NW
AREAS WITH THE APPROACH OF AN EMBEDDED SHORT WAVE TROF IN THE
APPROACHING LONG WAVE TROF...AND ALSO IN THE VICINITY OF AN AREAS OF
LOW LEVEL THETA E CONVERGENCE. OTHERWISE...KEPT HIGHS TODAY ABOVE
EVEN THE WARMER GFS/MAV WITH 850 MB TEMPS PUSHING 17C WITH
INCREASING UPPER LEVEL SUBSIDENCE.

&&

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 503 AM EDT SUN MAY 19 2013

NEGATIVELY TILTED LONGWAVE TROUGH CURRENTLY OVER THE ROCKY MOUNTAINS
WILL FULLY TRANSITION TO AN EXPANSIVE CLOSED LOW BY MONDAY AND WILL
BRING INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS IN OUR AREA
THROUGH MIDWEEK AS IT VERY SLOWLY PROGRESSES EASTWARD. PRECIP
CHANCES ON MONDAY STILL A BIT OF A QUESTION MARK THOUGH. SURFACE
FRONTAL BOUNDARY WILL BE WELL NORTH OF HERE BY MONDAY AFTERNOON WITH
GOOD SOUTHWEST FLOW PUSHING 850MB TEMPS TO AROUND 19C. MIXING THIS
TO THE SURFACE YIELDS AFTERNOON TEMPS APPROACHING 90F...IN LINE WITH
A CONSENSUS OF LATEST MOS GUIDANCE. NOT UNHEARD OF TO REACH 90F THIS
EARLY BUT CERTAINLY NOT COMMON. SURFACE DEWPOINTS WILL ALSO BE
CREEPING INTO THE MID AND PERHAPS UPPER 60S. 70F DEWPOINTS SEEN IN
RAW GUIDANCE LIKELY A BIT OVERZEALOUS BUT MODIFIED SOUNDINGS STILL
SHOW A HEALTHY AMOUNT OF CONDITIONAL INSTABILITY. QUESTION CONTINUES
TO BE HOW STRONG THE CAP WILL BE OVER OUR AREA. SOUTHERN GREAT LAKES
CONTINUE TO BE LARGELY UNDER THE INFLUENCE OF MIDLEVEL RIDGING ON
MONDAY AND THE ASSOCIATED ANTICYCLONIC VORTICITY SHOULD FAVOR A
DECENT SUBSIDENCE INVERSION...AT LEAST EARLY IN THE DAY. POTENTIAL
EXISTS FOR MIDLEVEL HEIGHT FALLS TO PUSH FAR ENOUGH EAST BY LATE IN
THE DAY TO ALLOW FOR CONVECTIVE INITIATION AND DOWNSTREAM
PROPAGATION...AS SEEN IN NEWEST 00Z NAM...BUT STILL FEEL THAT
LARGELY CUTOFF NATURE TO UPSTREAM HEIGHT ANOMALY FAVORS SLOWER
PROGRESSION SEEN IN THE LATEST GFS SOLUTION. WILL THEREFORE MAINTAIN
RELATIVELY LOW POPS DURING THE DAY WITH THE BEST CHANCE ACROSS THE
NORTHWEST DURING THE LATE AFTERNOON/EARLY EVENING. CHANCES INCREASE
POST 00Z AS DECAYING CONVECTION EVENTUALLY SPREADS EAST BUT LACK OF
GOOD SYNOPTIC FORCING MAY LIMIT COVERAGE/AMOUNTS AFTER THE LOSS OF
DAYTIME HEATING. SEVERE WEATHER REMAINS POSSIBLE IF CONVECTION
ARRIVES EARLY ENOUGH. SHEAR VALUES ARE LESS THAN STELLAR BUT DO
INCREASE IN THE WEST BY THE END OF THE DAY. THIS COUPLED WITH GOOD
DIURNALLY DRIVEN INSTABILITY WARRANTS CONTINUED CONDITIONAL THREAT.

PRECIP CHANCES/COVERAGE WILL INCREASE HEADING INTO TUES AND WED AS
THE VERTICALLY STACKED LOW GRADUALLY APPROACHES THE GREAT LAKES.
BROAD WARM/MOIST AIR ADVECTION WILL SUPPORT WIDESPREAD SHOWERS AND
THUNDERSTORMS ACROSS THE ENTIRE REGION. ALSO EXPECT SEVERAL MIDLEVEL
WAVES TO RIPPLE THROUGH THE REGION AND ENHANCE PRECIP
COVERAGE/INTENSITY BUT EXACT TIMING AND LOCATION WILL DEPEND ON
MESOSCALE DETAILS IMPOSSIBLE TO RESOLVE AT THIS TIME RANGE. TIMING
OF THESE MESOSCALE FEATURES WILL ALSO IMPACT OUR SEVERE WEATHER
CHANCES. ANY BREAK IN PRECIP ON TUESDAY COULD ALLOW FOR ENOUGH
DIURNAL INSTABILITY TO SUPPORT SEVERE WEATHER GIVEN DECENT WIND
PROFILES BUT FORECAST SOUNDINGS SHOW INCREASINGLY MOIST ADIABATIC
LAPSE RATES THAT WILL LIKELY INHIBIT OUR SEVERE CHANCES...ESPECIALLY
BY WEDNESDAY. SIGNIFICANT DISAGREEMENT BETWEEN ECMWF AND GFS ON HOW
QUICKLY UPPER LOW GETS REABSORBED INTO MEAN FLOW. THIS WILL HAVE A
LARGE IMPACT ON PRECIP CHANCES THURSDAY BUT EXPECT THERE WILL BE AT
LEAST SOME RESIDUAL SHOWERS IN THE WAKE OF DEPARTING LOW. NORTHWEST
FLOW WILL RETURN BY FRIDAY WITH COOL AND DRY CONDITIONS EXPECTED FOR
AT LEAST THE FIRST HALF OF THE WEEKEND.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 620 AM EDT SUN MAY 19 2013

A TIGHT MOISTURE GRADIENT REMAINED OVER THE AREA...WITH DEW
POINTS MUCH HIGHER JUST SOUTH OF THE TERMINALS. AFTERNOON CAPES
OF 2000 TO 3000 J/KG WOULD SUPPORT CONVECTION...BUT GIVEN LIGHT
WIND FIELDS AND NOTHING TO FORCE OR FOCUS CONVECTION...KEPT TAFS
DRY WITH VFR CONDITIONS. WINDS SHOULD REMAIN EAST TO SOUTHEAST
UNDER 10 KNOTS.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...LOTHAMER
SHORT TERM...SKIPPER
LONG TERM...AGD
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIND 191425
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1022 AM EDT SUN MAY 19 2013

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

&&

.SYNOPSIS...
ISSUED AT 307 AM EDT SUN MAY 19 2013

A WEAK RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE AREA
TODAY...KEEPING DRY AND WARM WEATHER ACROSS CENTRAL INDIANA THROUGH
THE BEGINNING OF THE WORK WEEK. A FEW STORMY DAYS ARE POSSIBLE
DURING THE MIDDLE OF THE WEEK AS A STRONGER AREA OF LOW PRESSURE
DEVELOPS OVER THE PLAINS STATES AND ALLOWS MORE FAVORABLE CONDITIONS
FOR STORMS ACROSS INDIANA.

&&

.NEAR TERM /REST OF TODAY/...
ISSUED AT 1022 AM EDT SUN MAY 19 2013

AREAS OF FOG LINGERING OVER SOME OF THE EAST CENTRAL ZONES AT THIS
TIME...BUT SATELLITE INDICATES RAPID IMPROVEMENT IN THESE AREAS OVER
THE NEXT HOUR OR SO.

OTHERWISE...CONVECTIVE TEMPERATURES REMAIN RATHER LOW TODAY...BUT
NEAR TERM MODEL SOUNDINGS SUGGEST AIR MASS WILL BECOME INCREASINGLY
CAPPED OFF AS THE DAY GOES BY. AS A RESULT...THERE SHOULD BE QUITE A
BIT OF DIURNAL CLOUDS DEVELOP...BUT THINK CHANCES OF CONVECTION WILL
REMAIN LOW. WILL KEEP THE SMALL CHANCE POP OVER THE FAR EAST/SOUTHEAST
THIS AFTERNOON CLOSEST TO REMNANT UPPER LOW.

THIS MORNING/S UPPER AIR SUGGEST HIGHS TODAY MAY A LITTLE
WARM...HOWEVER CURRENT TEMPERATURES RUNNING A LITTLE HIGHER THAN
WHAT WAS EXPECTED BY THIS TIME...SO WILL LEAVE THE HIGHS ALONE.

PREVIOUS DISCUSSION FOLLOWS.

PATCHY FOG WILL HAS ALREADY BEGUN TO FORM WITH A MOIST AIRMASS AND
SOME CLEARING THIS MORNING. BEST CHANCES FOR FOG WILL BE IN AREAS
THAT SAW RAIN YESTERDAY. HAVE ADDED PATCHY FOG TO THE FORECAST AND
THE HAZARDOUS WEATHER OUTLOOK WITH AREAS OF FOG WHERE VISIBILITIES
ARE INDICATING LESS THAN A MILE ACROSS THE SOUTHERN TIER OF
COUNTIES.

MODELS ARE SHOWING LIGHT SHOWERS POSSIBLY DEVELOPING ACROSS THE FAR
EASTERN TIER OF COUNTIES LATE THIS MORNING AND THROUGH THE
AFTERNOON. HAVE ADDED A SLIGHT CHANCE FOR THIS AREA DURING THIS TIME
AS NOT NOT VERY CONFIDENT SHOWERS AND/OR THUNDERSTORMS WILL MAKE IT
THIS FAR WEST WITH A RIDGE BUILDING IN.

TEMPERATURES ON THE WARM SIDE TODAY WITH HIGHS AVERAGING IN THE MID
80S. DID NOT STRAY FAR FROM MOS FOR HIGHS.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
ISSUED AT 307 AM EDT SUN MAY 19 2013

STARTING TONIGHT LEANED CLOSER TO WARMER MAV GUIDANCE FOR
TEMPERATURES AS GOOD WARM AIR ADVECTION WILL BE IN PLACE (ESPECIALLY
FOR MONDAY). A DRY FORECAST WILL GENERALLY PREVAIL UNTIL POSSIBLY
LATE MONDAY AFTERNOON WHEN A DEVELOPING LOW OVER THE CENTRAL PLAINS
MOVES INTO THE AREA.

MODELS SHOW A STRONG UPPER LOW MOVING TOWARD INDIANA LATE MONDAY
NIGHT INTO TUESDAY. AN ALREADY WARM AND MOIST AIR MASS COMBINED WITH
A DEVELOPING FRONTAL BOUNDARY ACROSS THE AREA...AND AN UPPER LOW
MOVING TOWARD THE AREA EJECTING S/WV TOWARDS THE AREA SHOULD PROVIDE
MANY SOURCES FOR CONVECTIVE INITIATION. INDICES FOR TUESDAY AND
TUESDAY NIGHT INDICATE THAT SEVERE WEATHER MAY OCCUR.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
ISSUED AT 229 AM EDT SUN MAY 19 2013

CONTINUE TO EXPECT AN ACTIVE PERIOD THROUGH THE LATTER PART OF THE
COMING WEEK AS A LOW PRESSURE SYSTEM MOVES EXTREMELY SLOWLY OUT
OF THE UPPER MIDWEST AND INTO THE MID ATLANTIC STATES BY THE END
OF THE WEEK. ON THIS...LONG TERM GUIDANCE IS IN GOOD AGREEMENT AND
INITIALIZATION HANDLED WELL.

VERY LATE IN THE PERIOD...INTO THE HOLIDAY WEEKEND...GFS KEEPS A
BROAD SURFACE RIDGE OVER THE AREA...AND EURO DOES TO AN EXTENT AS
WELL...BUT EURO IS MUCH MORE BULLISH ABOUT DEVELOPING PRECIP AND
MOVING IT INTO THE AREA LATE IN THE PERIOD. HAVE A HARD TIME
BUYING THIS WITH SURFACE RIDGING STILL IN THE AREA AND MUCH OF THE
PRECIP DEVELOPING DIRECTLY UNDER AN UPPER LEVEL RIDGE. WILL REMOVE
POPS FROM LATE IN THE PERIOD AND CONTINUE WITH A DRY FORECAST
BEYOND FRIDAY.

TEMPS WERE INITIALIZED FAIRLY WELL AND ONLY REQUIRED MINOR TWEAKS.

&&

.AVIATION /DISCUSSION FOR THE 15Z IND TAF UPDATE/...

HEATING AND MIXING IS RESUMING ACROSS THE AREA...AND MORNING MVFR
TO IFR FOG HAVE BURNED OFF. THUS VFR CONDITIONS ARE EXPECTED THE
REST OF THE AFTERNOON...AS CONVECTIVE TEMPERATURES SUGGEST SOME
SCT-BKN CU DEVELOPING WITH BASES NEAR 4000FT. ONGOING TAFS HANDLE
THIS WELL.

PREVIOUS DISCUSSION BELOW.

/DISCUSSION FOR THE 19/12Z TAFS/...
ISSUED AT 657 AM EDT SUN MAY 19 2013

IFR OR WORSE CONDITIONS THIS MORNING AT THE OUTLYING SITES...WITH
VLIFR AT HUF AND ESPECIALLY BMG. IND MAY FLUCTUATE BETWEEN VFR AND
HIGH END MVFR THIS MORNING.

FOG WILL BURN OFF IN TYPICAL DIURNAL FASHION THIS MORNING...BUT THIS
WILL LIKELY TAKE AT LEAST THE FIRST FEW HOURS...ESPECIALLY AT
HUF/BMG WHERE CONDITIONS HAVE BEEN WORST. WILL MAKE FINAL
DETERMINATION ON HOW TO HANDLE FOG NEAR ISSUANCE TIME WITH
FLUCTUATIONS LIKELY.

LATER TODAY...EXPECT SCT-BKN DIURNAL CUMULUS DEVELOPMENT AROUND
3500-4000 FT. MAINLY HIGH CLOUDS EXPECTED TONIGHT. FOG MAY AGAIN
DEVELOP...BUT WILL LEAVE TO LATER PACKAGES FOR NOW.

WINDS WILL BE 10KT OR LESS THROUGHOUT THE PERIOD...MAINLY OUT OF THE
SOUTH/SOUTHEAST.


&&

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

$$

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

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

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

000
FXUS63 KIND 191414
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1014 AM EDT SUN MAY 19 2013

.UPDATE...
AVIATION SECTION UPDATED

&&

.SYNOPSIS...
ISSUED AT 307 AM EDT SUN MAY 19 2013

A WEAK RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE AREA
TODAY...KEEPING DRY AND WARM WEATHER ACROSS CENTRAL INDIANA THROUGH
THE BEGINNING OF THE WORK WEEK. A FEW STORMY DAYS ARE POSSIBLE
DURING THE MIDDLE OF THE WEEK AS A STRONGER AREA OF LOW PRESSURE
DEVELOPS OVER THE PLAINS STATES AND ALLOWS MORE FAVORABLE CONDITIONS
FOR STORMS ACROSS INDIANA.

&&

.NEAR TERM /TODAY/...
ISSUED AT 307 AM EDT SUN MAY 19 2013

PATCHY FOG WILL HAS ALREADY BEGUN TO FORM WITH A MOIST AIRMASS AND
SOME CLEARING THIS MORNING. BEST CHANCES FOR FOG WILL BE IN AREAS
THAT SAW RAIN YESTERDAY. HAVE ADDED PATCHY FOG TO THE FORECAST AND
THE HAZARDOUS WEATHER OUTLOOK WITH AREAS OF FOG WHERE VISIBILITIES
ARE INDICATING LESS THAN A MILE ACROSS THE SOUTHERN TIER OF
COUNTIES.

MODELS ARE SHOWING LIGHT SHOWERS POSSIBLY DEVELOPING ACROSS THE FAR
EASTERN TIER OF COUNTIES LATE THIS MORNING AND THROUGH THE
AFTERNOON. HAVE ADDED A SLIGHT CHANCE FOR THIS AREA DURING THIS TIME
AS NOT NOT VERY CONFIDENT SHOWERS AND/OR THUNDERSTORMS WILL MAKE IT
THIS FAR WEST WITH A RIDGE BUILDING IN.

TEMPERATURES ON THE WARM SIDE TODAY WITH HIGHS AVERAGING IN THE MID
80S. DID NOT STRAY FAR FROM MOS FOR HIGHS.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
ISSUED AT 307 AM EDT SUN MAY 19 2013

STARTING TONIGHT LEANED CLOSER TO WARMER MAV GUIDANCE FOR
TEMPERATURES AS GOOD WARM AIR ADVECTION WILL BE IN PLACE (ESPECIALLY
FOR MONDAY). A DRY FORECAST WILL GENERALLY PREVAIL UNTIL POSSIBLY
LATE MONDAY AFTERNOON WHEN A DEVELOPING LOW OVER THE CENTRAL PLAINS
MOVES INTO THE AREA.

MODELS SHOW A STRONG UPPER LOW MOVING TOWARD INDIANA LATE MONDAY
NIGHT INTO TUESDAY. AN ALREADY WARM AND MOIST AIR MASS COMBINED WITH
A DEVELOPING FRONTAL BOUNDARY ACROSS THE AREA...AND AN UPPER LOW
MOVING TOWARD THE AREA EJECTING S/WV TOWARDS THE AREA SHOULD PROVIDE
MANY SOURCES FOR CONVECTIVE INITIATION. INDICES FOR TUESDAY AND
TUESDAY NIGHT INDICATE THAT SEVERE WEATHER MAY OCCUR.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
ISSUED AT 229 AM EDT SUN MAY 19 2013

CONTINUE TO EXPECT AN ACTIVE PERIOD THROUGH THE LATTER PART OF THE
COMING WEEK AS A LOW PRESSURE SYSTEM MOVES EXTREMELY SLOWLY OUT
OF THE UPPER MIDWEST AND INTO THE MID ATLANTIC STATES BY THE END
OF THE WEEK. ON THIS...LONG TERM GUIDANCE IS IN GOOD AGREEMENT AND
INITIALIZATION HANDLED WELL.

VERY LATE IN THE PERIOD...INTO THE HOLIDAY WEEKEND...GFS KEEPS A
BROAD SURFACE RIDGE OVER THE AREA...AND EURO DOES TO AN EXTENT AS
WELL...BUT EURO IS MUCH MORE BULLISH ABOUT DEVELOPING PRECIP AND
MOVING IT INTO THE AREA LATE IN THE PERIOD. HAVE A HARD TIME
BUYING THIS WITH SURFACE RIDGING STILL IN THE AREA AND MUCH OF THE
PRECIP DEVELOPING DIRECTLY UNDER AN UPPER LEVEL RIDGE. WILL REMOVE
POPS FROM LATE IN THE PERIOD AND CONTINUE WITH A DRY FORECAST
BEYOND FRIDAY.

TEMPS WERE INITIALIZED FAIRLY WELL AND ONLY REQUIRED MINOR TWEAKS.

&&

.AVIATION /DISCUSSION FOR THE 15Z IND TAF UPDATE/...

HEATING AND MIXING IS RESUMING ACROSS THE AREA...AND MORNING MVFR
TO IFR FOG HAVE BURNED OFF. THUS VFR CONDITIONS ARE EXPECTED THE
REST OF THE AFTERNOON...AS CONVECTIVE TEMPERATURES SUGGEST SOME
SCT-BKN CU DEVELOPING WITH BASES NEAR 4000FT. ONGOING TAFS HANDLE
THIS WELL.

PREVIOUS DISCUSSION BELOW.

/DISCUSSION FOR THE 19/12Z TAFS/...
ISSUED AT 657 AM EDT SUN MAY 19 2013

IFR OR WORSE CONDITIONS THIS MORNING AT THE OUTLYING SITES...WITH
VLIFR AT HUF AND ESPECIALLY BMG. IND MAY FLUCTUATE BETWEEN VFR AND
HIGH END MVFR THIS MORNING.

FOG WILL BURN OFF IN TYPICAL DIURNAL FASHION THIS MORNING...BUT THIS
WILL LIKELY TAKE AT LEAST THE FIRST FEW HOURS...ESPECIALLY AT
HUF/BMG WHERE CONDITIONS HAVE BEEN WORST. WILL MAKE FINAL
DETERMINATION ON HOW TO HANDLE FOG NEAR ISSUANCE TIME WITH
FLUCTUATIONS LIKELY.

LATER TODAY...EXPECT SCT-BKN DIURNAL CUMULUS DEVELOPMENT AROUND
3500-4000 FT. MAINLY HIGH CLOUDS EXPECTED TONIGHT. FOG MAY AGAIN
DEVELOP...BUT WILL LEAVE TO LATER PACKAGES FOR NOW.

WINDS WILL BE 10KT OR LESS THROUGHOUT THE PERIOD...MAINLY OUT OF THE
SOUTH/SOUTHEAST.


&&

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

$$

SYNOPSIS...SMF
NEAR TERM...SMF
SHORT TERM...SMF
LONG TERM....NIELD
AVIATION...NIELD

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

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

000
FXUS63 KIND 191057
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
657 AM EDT SUN MAY 19 2013

.UPDATE...

THE AVIATION SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 307 AM EDT SUN MAY 19 2013

A WEAK RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE AREA
TODAY...KEEPING DRY AND WARM WEATHER ACROSS CENTRAL INDIANA THROUGH
THE BEGINNING OF THE WORK WEEK. A FEW STORMY DAYS ARE POSSIBLE
DURING THE MIDDLE OF THE WEEK AS A STRONGER AREA OF LOW PRESSURE
DEVELOPS OVER THE PLAINS STATES AND ALLOWS MORE FAVORABLE CONDITIONS
FOR STORMS ACROSS INDIANA.

&&

.NEAR TERM /TODAY/...
ISSUED AT 307 AM EDT SUN MAY 19 2013

PATCHY FOG WILL HAS ALREADY BEGUN TO FORM WITH A MOIST AIRMASS AND
SOME CLEARING THIS MORNING. BEST CHANCES FOR FOG WILL BE IN AREAS
THAT SAW RAIN YESTERDAY. HAVE ADDED PATCHY FOG TO THE FORECAST AND
THE HAZARDOUS WEATHER OUTLOOK WITH AREAS OF FOG WHERE VISIBILITIES
ARE INDICATING LESS THAN A MILE ACROSS THE SOUTHERN TIER OF
COUNTIES.

MODELS ARE SHOWING LIGHT SHOWERS POSSIBLY DEVELOPING ACROSS THE FAR
EASTERN TIER OF COUNTIES LATE THIS MORNING AND THROUGH THE
AFTERNOON. HAVE ADDED A SLIGHT CHANCE FOR THIS AREA DURING THIS TIME
AS NOT NOT VERY CONFIDENT SHOWERS AND/OR THUNDERSTORMS WILL MAKE IT
THIS FAR WEST WITH A RIDGE BUILDING IN.

TEMPERATURES ON THE WARM SIDE TODAY WITH HIGHS AVERAGING IN THE MID
80S. DID NOT STRAY FAR FROM MOS FOR HIGHS.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
ISSUED AT 307 AM EDT SUN MAY 19 2013

STARTING TONIGHT LEANED CLOSER TO WARMER MAV GUIDANCE FOR
TEMPERATURES AS GOOD WARM AIR ADVECTION WILL BE IN PLACE (ESPECIALLY
FOR MONDAY). A DRY FORECAST WILL GENERALLY PREVAIL UNTIL POSSIBLY
LATE MONDAY AFTERNOON WHEN A DEVELOPING LOW OVER THE CENTRAL PLAINS
MOVES INTO THE AREA.

MODELS SHOW A STRONG UPPER LOW MOVING TOWARD INDIANA LATE MONDAY
NIGHT INTO TUESDAY. AN ALREADY WARM AND MOIST AIR MASS COMBINED WITH
A DEVELOPING FRONTAL BOUNDARY ACROSS THE AREA...AND AN UPPER LOW
MOVING TOWARD THE AREA EJECTING S/WV TOWARDS THE AREA SHOULD PROVIDE
MANY SOURCES FOR CONVECTIVE INITIATION. INDICES FOR TUESDAY AND
TUESDAY NIGHT INDICATE THAT SEVERE WEATHER MAY OCCUR.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
ISSUED AT 229 AM EDT SUN MAY 19 2013

CONTINUE TO EXPECT AN ACTIVE PERIOD THROUGH THE LATTER PART OF THE
COMING WEEK AS A LOW PRESSURE SYSTEM MOVES EXTREMELY SLOWLY OUT
OF THE UPPER MIDWEST AND INTO THE MID ATLANTIC STATES BY THE END
OF THE WEEK. ON THIS...LONG TERM GUIDANCE IS IN GOOD AGREEMENT AND
INITIALIZATION HANDLED WELL.

VERY LATE IN THE PERIOD...INTO THE HOLIDAY WEEKEND...GFS KEEPS A
BROAD SURFACE RIDGE OVER THE AREA...AND EURO DOES TO AN EXTENT AS
WELL...BUT EURO IS MUCH MORE BULLISH ABOUT DEVELOPING PRECIP AND
MOVING IT INTO THE AREA LATE IN THE PERIOD. HAVE A HARD TIME
BUYING THIS WITH SURFACE RIDGING STILL IN THE AREA AND MUCH OF THE
PRECIP DEVELOPING DIRECTLY UNDER AN UPPER LEVEL RIDGE. WILL REMOVE
POPS FROM LATE IN THE PERIOD AND CONTINUE WITH A DRY FORECAST
BEYOND FRIDAY.

TEMPS WERE INITIALIZED FAIRLY WELL AND ONLY REQUIRED MINOR TWEAKS.

&&

.AVIATION /DISCUSSION FOR THE 19/12Z TAFS/...
ISSUED AT 657 AM EDT SUN MAY 19 2013

IFR OR WORSE CONDITIONS THIS MORNING AT THE OUTLYING SITES...WITH
VLIFR AT HUF AND ESPECIALLY BMG. IND MAY FLUCTUATE BETWEEN VFR AND
HIGH END MVFR THIS MORNING.

FOG WILL BURN OFF IN TYPICAL DIURNAL FASHION THIS MORNING...BUT THIS
WILL LIKELY TAKE AT LEAST THE FIRST FEW HOURS...ESPECIALLY AT
HUF/BMG WHERE CONDITIONS HAVE BEEN WORST. WILL MAKE FINAL
DETERMINATION ON HOW TO HANDLE FOG NEAR ISSUANCE TIME WITH
FLUCTUATIONS LIKELY.

LATER TODAY...EXPECT SCT-BKN DIURNAL CUMULUS DEVELOPMENT AROUND
3500-4000 FT. MAINLY HIGH CLOUDS EXPECTED TONIGHT. FOG MAY AGAIN
DEVELOP...BUT WILL LEAVE TO LATER PACKAGES FOR NOW.

WINDS WILL BE 10KT OR LESS THROUGHOUT THE PERIOD...MAINLY OUT OF THE
SOUTH/SOUTHEAST.

&&

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

&&

$$

SYNOPSIS...SMF
NEAR TERM...SMF
SHORT TERM...SMF
LONG TERM....NIELD
AVIATION...NIELD

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

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

000
FXUS63 KIWX 191035
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
635 AM EDT SUN MAY 19 2013

.SYNOPSIS...
ISSUED AT 620 AM EDT SUN MAY 19 2013

A WEAK UPPER LOW WILL EJECT NORTHEAST TODAY...WITH A SHOWER OR
THUNDERSTORM POSSIBLE OVER MAINLY OHIO. OTHERWISE...AN UPPER LEVEL
RIDGE WILL BUILD NORTHEAST ACROSS THE MIDWEST INTO THE OHIO VALLEY
REGION EARLY THIS WEEK. TEMPERATURES WILL BECOME HOT BY MONDAY WITH
HIGHS AROUND 90. AS THE UPPER LEVEL RIDGE BUILDS EAST...SHOWERS AND
THUNDERSTORMS WILL SPREAD EAST IN ADVANCE OF A COLD FRONT AND
UPPER LEVEL DISTURBANCE MONDAY THROUGH THURSDAY. RAINFALL AMOUNTS
SHOULD EXCEED AN INCH BY LATE IN THE WEEK.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 503 AM EDT SUN MAY 19 2013

AN UPPER LOW SOUTH OF THE AREA WILL EJECT EAST OUT OF THE REGION
TODAY. IN ITS WAKE...A LINGERING SURFACE DEW POINT GRADIENT WAS
STILL OVER THE AREA...BUT NOT AS PRONOUNCED AS THE LAST COUPLE OF
NIGHTS. CONCERN WITH DAYTIME HEATING AND AFTERNOON/EARLY EVENING
CAPES TOPPING 3000 J/KG PER NAM BUF/KIT OVER SOUTHWEST AREAS.
HOWEVER... THE ENVIRONMENT WILL REMAIN VERY LIGHTLY SHEARED WITH
REALLY NOTHING TO FOCUS OR FORCE CONVECTION...OTHER THAN THE
MODIFYING DEW POINT BOUNDARY. FOR NOW...KEPT SHOWERS/STORMS OUT OF
THE FCST TODAY. KEPT A LOW CHANCE FOR SHOWERS/STORMS TONIGHT OVER NW
AREAS WITH THE APPROACH OF AN EMBEDDED SHORT WAVE TROF IN THE
APPROACHING LONG WAVE TROF...AND ALSO IN THE VICINITY OF AN AREAS OF
LOW LEVEL THETA E CONVERGENCE. OTHERWISE...KEPT HIGHS TODAY ABOVE
EVEN THE WARMER GFS/MAV WITH 850 MB TEMPS PUSHING 17C WITH
INCREASING UPPER LEVEL SUBSIDENCE.

&&

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 503 AM EDT SUN MAY 19 2013

NEGATIVELY TILTED LONGWAVE TROUGH CURRENTLY OVER THE ROCKY MOUNTAINS
WILL FULLY TRANSITION TO AN EXPANSIVE CLOSED LOW BY MONDAY AND WILL
BRING INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS IN OUR AREA
THROUGH MIDWEEK AS IT VERY SLOWLY PROGRESSES EASTWARD. PRECIP
CHANCES ON MONDAY STILL A BIT OF A QUESTION MARK THOUGH. SURFACE
FRONTAL BOUNDARY WILL BE WELL NORTH OF HERE BY MONDAY AFTERNOON WITH
GOOD SOUTHWEST FLOW PUSHING 850MB TEMPS TO AROUND 19C. MIXING THIS
TO THE SURFACE YIELDS AFTERNOON TEMPS APPROACHING 90F...IN LINE WITH
A CONSENSUS OF LATEST MOS GUIDANCE. NOT UNHEARD OF TO REACH 90F THIS
EARLY BUT CERTAINLY NOT COMMON. SURFACE DEWPOINTS WILL ALSO BE
CREEPING INTO THE MID AND PERHAPS UPPER 60S. 70F DEWPOINTS SEEN IN
RAW GUIDANCE LIKELY A BIT OVERZEALOUS BUT MODIFIED SOUNDINGS STILL
SHOW A HEALTHY AMOUNT OF CONDITIONAL INSTABILITY. QUESTION CONTINUES
TO BE HOW STRONG THE CAP WILL BE OVER OUR AREA. SOUTHERN GREAT LAKES
CONTINUE TO BE LARGELY UNDER THE INFLUENCE OF MIDLEVEL RIDGING ON
MONDAY AND THE ASSOCIATED ANTICYCLONIC VORTICITY SHOULD FAVOR A
DECENT SUBSIDENCE INVERSION...AT LEAST EARLY IN THE DAY. POTENTIAL
EXISTS FOR MIDLEVEL HEIGHT FALLS TO PUSH FAR ENOUGH EAST BY LATE IN
THE DAY TO ALLOW FOR CONVECTIVE INITIATION AND DOWNSTREAM
PROPAGATION...AS SEEN IN NEWEST 00Z NAM...BUT STILL FEEL THAT
LARGELY CUTOFF NATURE TO UPSTREAM HEIGHT ANOMALY FAVORS SLOWER
PROGRESSION SEEN IN THE LATEST GFS SOLUTION. WILL THEREFORE MAINTAIN
RELATIVELY LOW POPS DURING THE DAY WITH THE BEST CHANCE ACROSS THE
NORTHWEST DURING THE LATE AFTERNOON/EARLY EVENING. CHANCES INCREASE
POST 00Z AS DECAYING CONVECTION EVENTUALLY SPREADS EAST BUT LACK OF
GOOD SYNOPTIC FORCING MAY LIMIT COVERAGE/AMOUNTS AFTER THE LOSS OF
DAYTIME HEATING. SEVERE WEATHER REMAINS POSSIBLE IF CONVECTION
ARRIVES EARLY ENOUGH. SHEAR VALUES ARE LESS THAN STELLAR BUT DO
INCREASE IN THE WEST BY THE END OF THE DAY. THIS COUPLED WITH GOOD
DIURNALLY DRIVEN INSTABILITY WARRANTS CONTINUED CONDITIONAL THREAT.

PRECIP CHANCES/COVERAGE WILL INCREASE HEADING INTO TUES AND WED AS
THE VERTICALLY STACKED LOW GRADUALLY APPROACHES THE GREAT LAKES.
BROAD WARM/MOIST AIR ADVECTION WILL SUPPORT WIDESPREAD SHOWERS AND
THUNDERSTORMS ACROSS THE ENTIRE REGION. ALSO EXPECT SEVERAL MIDLEVEL
WAVES TO RIPPLE THROUGH THE REGION AND ENHANCE PRECIP
COVERAGE/INTENSITY BUT EXACT TIMING AND LOCATION WILL DEPEND ON
MESOSCALE DETAILS IMPOSSIBLE TO RESOLVE AT THIS TIME RANGE. TIMING
OF THESE MESOSCALE FEATURES WILL ALSO IMPACT OUR SEVERE WEATHER
CHANCES. ANY BREAK IN PRECIP ON TUESDAY COULD ALLOW FOR ENOUGH
DIURNAL INSTABILITY TO SUPPORT SEVERE WEATHER GIVEN DECENT WIND
PROFILES BUT FORECAST SOUNDINGS SHOW INCREASINGLY MOIST ADIABATIC
LAPSE RATES THAT WILL LIKELY INHIBIT OUR SEVERE CHANCES...ESPECIALLY
BY WEDNESDAY. SIGNIFICANT DISAGREEMENT BETWEEN ECMWF AND GFS ON HOW
QUICKLY UPPER LOW GETS REABSORBED INTO MEAN FLOW. THIS WILL HAVE A
LARGE IMPACT ON PRECIP CHANCES THURSDAY BUT EXPECT THERE WILL BE AT
LEAST SOME RESIDUAL SHOWERS IN THE WAKE OF DEPARTING LOW. NORTHWEST
FLOW WILL RETURN BY FRIDAY WITH COOL AND DRY CONDITIONS EXPECTED FOR
AT LEAST THE FIRST HALF OF THE WEEKEND.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 620 AM EDT SUN MAY 19 2013

A TIGHT MOISTURE GRADIENT REMAINED OVER THE AREA...WITH DEW
POINTS MUCH HIGHER JUST SOUTH OF THE TERMINALS. AFTERNOON CAPES
OF 2000 TO 3000 J/KG WOULD SUPPORT CONVECTION...BUT GIVEN LIGHT
WIND FIELDS AND NOTHING TO FORCE OR FOCUS CONVECTION...KEPT TAFS
DRY WITH VFR CONDITIONS. WINDS SHOULD REMAIN EAST TO SOUTHEAST
UNDER 10 KNOTS.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...MARSILI/KG
SHORT TERM...SKIPPER
LONG TERM...AGD
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA