Area Forecast Discussion
Issued by NWS Indianapolis, IN

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KIND 012000
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
400 PM EDT MON SEP 1 2014

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

&&

.SYNOPSIS...
ISSUED AT 321 PM EDT MON SEP 1 2014

WIDESPREAD RAIN SHOWERS AND THUNDERSTORMS WILL IMPACT CENTRAL
INDIANA TONIGHT THROUGH TOMORROW MORNING AS AN UPPER TROUGH AND
ASSOCIATED COLD FRONT TRACK ACROSS THE AREA. AFTER CALM CONDITIONS
ON WEDNESDAY...A WARM HUMID AIRMASS WILL ENTER THE FORECAST AREA
AT THE END OF THE WEEK...ALSO BRINGING THE THREAT OF ADDITIONAL
SHOWERS AND THUNDERSTORMS. FURTHER OUT...HIGH TEMPS WILL DROP
DRASTICALLY FROM THE UPPER 80S/LOW 90S ON THURSDAY AND FRIDAY TO
70S FOR THE WEEKEND.


&&

.NEAR TERM /TONIGHT THROUGH TOMORROW/...

ISSUED AT 321 PM EDT MON SEP 1 2014

THE MAIN FOCUS OF THE NEAR TERM IS THUNDERSTORM CHANCES AND SEVERE
THREAT FOR TONIGHT.

SUBSTANTIAL CLOUD COVER HAS INHIBITED ENVIRONMENT FROM
DESTABILIZING THIS AFTERNOON...AND BEST DYNAMICS WILL BE BOTH
NORTH AND SOUTH OF CENTRAL INDIANA. AS A RESULT...CENTRAL INDIANA
HAS BEEN REMOVED FROM THE SEVERE THREAT FOR TONIGHT.
HOWEVER...ISOLATED STRONG THUNDERSTORMS CANNOT BE RULED OUT
ENTIRELY AS ENVIRONMENT DESTABILIZES A BIT LATE THIS
AFTERNOON...AND A LOW LEVEL JET PROVIDES SOME ENHANCEMENT ALONG
AND AHEAD OF COLD FRONT PROGGED FOR TONIGHT.

AT THIS POINT...HEAVY RAIN/FLOODING WILL BE THE MAIN THREAT
OVERNIGHT...BUT WILL NOT ISSUE WATCH AT THIS TIME DUE TO
INCONSISTENCIES IN MODELS IN REGARD TO LOCATION AND AMOUNTS. THE
GFS AND CANADIAN ARE TRENDING WITH HIGHER AMOUNTS THAN THE
NAM/EURO...IN THE 2 TO 3 INCH RANGE.  BUT THE GFS TAKES THE HEAVY
RAIN BAND OVER CENTRAL PORTIONS OF THE FORECAST AREA...AND THE
CANADIAN TAKES IT OVER THE NORTHERN COUNTIES. MEANWHILE...THE NAM
AND EURO ARE CONSISTENT IN REGARD TO LOCATION OF RAIN /CENTRAL
PORTIONS/...BUT ARE TRENDING MORE TOWARD 1 TO 2 INCHES. WITHOUT
ANY SIGNIFICANT RAINFALLS RECENTLY EITHER...HAVE TRENDED TOWARD
NO WATCH.

ACTIVITY WILL TAPER OFF RATHER QUICKLY FROM NORTHWEST TO SOUTHEAST
AROUND MID MORNING TOMORROW AS ISENTROPIC LIFT WEAKENS. DRIER AIR
WILL BE OVER MOST OF THE AREA BY TOMORROW AFTERNOON...EXCEPT THE
FAR SOUTHEAST COUNTIES...WILL HOLD ONTO LOW END POPS OVER THAT
AREA INTO THE EARLY EVENING HOURS.

TEMPS...OVERNIGHT LOWS WILL BE IN THE UPPER 60S/LOW 70S WITH
PLENTY OF CLOUD COVER OVER THE AREA...STUCK CLOSE TO GUIDANCE.

&&

.SHORT TERM /TOMORROW NIGHT THROUGH THURSDAY/...

ISSUED AT 321 PM EDT MON SEP 1 2014

THE MAIN FOCUS OF THE SHORT TERM PERIOD WILL BE THE RE-
INTRODUCTION OF POPS INTO THE FORECAST ON WEDNESDAY NIGHT
AND THURSDAY.

ZONAL FLOW ALOFT AND HIGH PRESSURE AT THE SURFACE WILL RESULT IN
DRY CONDITIONS FOR TOMORROW NIGHT THROUGH WEDNESDAY. HOWEVER...A
WARM FRONT WILL START PUSHING INTO THE AREA FROM THE SOUTHWEST ON
WEDNESDAY NIGHT. MODELS ARE NOT AGREEING ON TIMING...WITH THE GFS
A TAD FASTER THAN THE EURO IN REGARD TO START TIME OF PRECIP.
SO...WILL JUST INTRODUCE SLIGHT CHANCE POPS OVER THE SOUTHWEST
COUNTIES ON WEDNESDAY NIGHT...EXPANDING FURTHER INTO CENTRAL
INDIANA ON THURSDAY.

TEMPS...STUCK CLOSE TO GUIDANCE THROUGH WEDNESDAY NIGHT AND
TRENDED ON THE WARMER SIDE FOR THURSDAY WITH APPROACHING WARM FRONT.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...

ISSUED AT 321 PM EDT MON SEP 1 2014

MODEL GUIDANCE REMAINS IN VERY GOOD AGREEMENT ON THE MAIN WEATHER
IMPACTS THROUGH THE EXTENDED. A VERY WARM AND HUMID AIRMASS WILL BE
PRESENT ACROSS THE OHIO VALLEY FOR THE END OF THE WEEK AS A STRONG
UPPER RIDGE IS CENTERED OVER THE TENNESSEE VALLEY AND SOUTHERN
APPALACHIANS. HIGH TEMPERATURES WILL BE AROUND 90 DEGREES ON FRIDAY.
A SHARP WAVE ALOFT MOVING ACROSS THE NORTHERN PLAINS WILL SERVE TO
BUCKLE THE RIDGE AND ENABLE A COLD FRONT TO DROP INTO THE OHIO
VALLEY WITH SCATTERED THUNDERSTORMS FROM FRIDAY AFTERNOON THROUGH
SATURDAY.

THE PASSAGE OF THE FRONT WILL USHER IN A MUCH COOLER AND DRIER
AIRMASS BEGINNING SUNDAY AS LARGE HIGH PRESSURE OVERSPREADS THE
LOWER GREAT LAKES. THE HIGH WILL REMAIN THE DOMINANT WEATHER FEATURE
FOR CENTRAL INDIANA INTO EARLY NEXT WEEK AS IT DRIFTS SLOWLY EAST
INTO NEW ENGLAND. HIGH TEMPS WILL FALL BACK INTO THE 70S SUNDAY AND
MONDAY WITH OVERNIGHT LOWS THE COOLEST SEEN IN THE REGION SINCE THE
MIDDLE OF AUGUST.


&&

.AVIATION /DISCUSSION FOR 011800Z TAF ISSUANCE/...
ISSUED AT 120 PM EDT MON SEP 1 2014

MVFR CEILINGS EXPECTED TO LIFT TO VFR THIS AFTERNOON...POOR FLYING
CONDITIONS LIKELY TO RETURN OVERNIGHT INTO TUESDAY MORNING IN
THUNDERSTORMS.

INSTABILITY BEING LIMITED SO FAR WITH HIGH LEVEL CONVECTIVE CLOUD
DEBRIS FROM EARLY MORNING STORMS OVER MISSOURI DRIFTING OVER THE
REGION. ADDITIONALLY...POCKETS OF MVFR STRATOCU FROM EARLIER
CONTINUE TO MIX OUT INTO A VFR CU FIELD. SCATTERED CONVECTION
ASSOCIATED WITH A SUBTLE MID LEVEL WAVE ALREADY EAST OF THE
FORECAST AREA WITH ADDITIONAL STORMS FIRING ALONG AN OLD OUTFLOW
BOUNDARY OVER THE LOWER GREAT LAKES. THIS BOUNDARY EXTENDS BACK
TO WHAT APPEARS TO BE A WEAK SURFACE LOW NEAR KSTL...AND VERY WELL
MAY SERVE AS THE INITIAL CATALYST FOR ISOLATED TO SCATTERED STORMS
TO DEVELOP LATER THIS AFTERNOON AS INSTABILITY INCREASES A BIT.
SHORT RANGE MODEL GUIDANCE HAS LEFT A LOT TO BE DESIRED SO FAR
TODAY...WITH THE WRF ALREADY OVERDOING CONVECTION. HARD TO JUSTIFY
MUCH GREATER THAN VCTS AT ALL SITES AS THE BOUNDARY MOVES INTO THE
REGION LATER THIS AFTERNOON. SOUTHWEST WINDS WILL CONTINUE TO GUST
AT 20-25KTS THROUGH THE REMAINDER OF THE AFTERNOON.

FOCUS FOR GREATER IMPACTS FROM CONVECTION REMAIN FOR TONIGHT AND
ESPECIALLY AFTER MIDNIGHT AS A GROWING MODEL CONSENSUS FAVORS A
CONVECTIVE CLUSTER DEVELOPING IN THE VICINITY OF LOW PRESSURE OVER
MISSOURI BY EARLY EVENING...GRADUALLY SPREADING NORTHEAST INTO
CENTRAL INDIANA FOR THE OVERNIGHT. WITH THE LOW LEVEL JET
STRENGTHENING ONCE AGAIN TONIGHT...EXPECT STORMS TO GO INTO EARLY
TUESDAY AS THE SURFACE LOW TRACKS THROUGH THE REGION. WILL
MAINTAIN PREVAILING THUNDER AT ALL TERMINALS...BUT BACK ONSET
TIMING TO 04-06Z. POTENTIAL EXISTS FOR IFR CONDITIONS WITHIN
HEAVIER STORMS TO CONTINUE THROUGH MID MORNING TUESDAY. WINDS WILL
VEER TO A W/NW DIRECTION ONCE THE LOW AND FRONT SHIFT EAST BY
MIDDAY...WITH JUST LINGERING SCATTERED SHOWERS EXPECTED BEFORE
RAIN ENDS IN THE AFTERNOON.


&&

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

&&

$$

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

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

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






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.