Area Forecast Discussion
Issued by NWS Northern Indiana

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 KIWX 261737
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
137 PM EDT TUE AUG 26 2014

.SYNOPSIS...
ISSUED AT 1048 AM EDT TUE AUG 26 2014

HOT AND HUMID CONDITIONS WILL CONTINUE TODAY AHEAD OF AN
APPROACHING COLD FRONT. THE COLD FRONT WILL SLOWLY DRIFT SOUTHWARD
OVER THE NEXT 24 HOURS. THIS FRONT WILL BE BRINGING SHOWERS AND
THUNDERSTORMS TO THE REGION. THE FRONT AND PRECIPITATION CHANCES WILL
DEPART THE AREA TOMORROW LEAVING WEDNESDAY NIGHT AND THURSDAY DRY.
HIGH TEMPERATURES TODAY WILL RANGE FROM THE UPPER 80S IN SOUTHERN
MICHIGAN TO THE LOWER 90S ALONG THE OHIO RIVER. LOW TEMPERATURES
TONIGHT WILL RANGE FROM THE LOWER 60S IN SOUTHERN MICHIGAN TO THE
UPPER 60S NEAR THE OHIO RIVER.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 413 AM EDT TUE AUG 26 2014

BACK EDGE OF DEPARTING WAVE WAS WORKING ACROSS WESTERN PARTS OF THE
AREA. IN ITS WAKE...VSBYS WERE RAPIDLY DROPPING WITH VALPARAISO AND
KNOX NOW SHOWING AT PATCHY...LOCALLY DENSE FOG. WOULD EXPECTED THIS
TREND TO EXPAND EAST AS CLEARING OCCURS. SOME CONCERN THAT DENSE FOG
COULD BECOME MORE WIDESPREAD ALONG AND WEST OF ROUTE 15 BUT FOR NOW
WILL GO WITH PRE 1ST PERIOD OF PATCHY FOG AND MONITOR.

COLD FRONT WILL SLOWLY SAG SOUTH INTO THE REGION TODAY BRINGING
ANOTHER SHOT AT SHOWERS AND THUNDERSTORMS. HIGH RES MODELS ALL
SUGGEST CONVECTIVE DEVELOPMENT SOMEWHERE FROM CENTRAL ILLINOIS INTO
NW PARTS OF THE FORECAST AREA TOWARDS 12Z WITH THIS THEN EXPANDING
SE WITH TIME THROUGH LATE AFTERNOON. AS OF WRITING THIS...A FEW
CELLS WERE RAPIDLY DEVELOPING IN EASTERN IOWA WHICH COULD BE THE
STARTS OF THINGS TO COME. WATER VAPOR LOOP SHOWING SOME INDICATIONS
OF A WAVE MOVING ACROSS EASTERN IOWA INTO ILLINOIS THAT COULD GET
THINGS MOVING. SPC MESOANALYSIS SHOWING 3500-4000 J/KG OF MOST
UNSTABLE CAPE OVER ILLINOIS AND AREAS OF WEAK CONVERGENCE. HAVE
ADJUSTED CHANCES FOR PRECIP TO FOCUS MAINLY NW AT THE START OF THE
PERIOD BUT HELD IN CHC RANGE FOR NOW. AS THE MORNING PROGRESSES ANY
CONVECTION SHOULD EITHER EXPAND OR DEVELOP FURTHER SOUTHEAST WHERE
HEATING WILL BE MORE FOCUS AND PRONOUNCED. BY 18Z A SWATH OF
MODERATE TO STRONG INSTABILITY SHOULD BE IN PLACE ACROSS SE HALF OF
THE AREA WHERE TEMPS SHOULD CLIMB INTO THE UPPER 80S TO NEAR 90. AS
HAS BEEN THE CASE...SHEAR PROFILES RATHER ANEMIC LENDING TO SLOW
MOVING STORMS CAPABLE OF HEAVY RAIN AND MAYBE AN ISOLATED STRONG
WIND GUST AS STORMS COLLAPSE.

FRONT SHOULD RESIDE ACROSS THE SOUTHERN COUNTIES THIS EVENING AND
THEN STALL OUT. MODELS HAD HINTED AT ADDITIONAL STORMS DEVELOPING
OVERNIGHT BUT NOT SURE EXACTLY WHERE BEST CONVERGENCE WILL EXIST SO
WILL DOWN PLAY SOMEWHAT AND KEEP IN SLGT CHC TO CHC RANGE.

&&

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 413 AM EDT TUE AUG 26 2014

CDFNT OVER WI/IA THIS MORNING IS EXPECTED TO BECOME MORE E-W
ORIENTED AND MOVE TO JUST SOUTH OF OUR CWA BY WED MORNING. A FEW
POST FRONTAL SHOWERS/TSTMS STILL PSBL WED AS A SHRTWV CURRENTLY OVER
SASK/MT DROPS SE ACROSS THE GRTLKS. SFC HIGH MOVG INTO THE UPR
GRTLKS WED WILL ADVECT COOLER/DRIER AIR INTO THE AREA BRINGING AN
END TO THE RECENT MUGGY CONDITIONS WITH HIGHS EXPECTED NEAR NORMAL
IN THE U70S/L80S AND DWPTS FALLING BACK TO THE L-M60S. SFC RIDGE
CROSSING THE CWA SHOULD PROVIDE DRY CONDITIONS WED NIGHT.
RADIATIONAL COOLING MAY BE LIMITED SOME BY HIGH CLOUDS SPILLING E-SE
FROM CONVECTION OVER THE PLAINS IN RESPONSE TO CUT-OFF LOW CROSSING
THE ROCKIES... THUS LOWS ONLY EXPECTED TO FALL INTO THE U50S NE TO
THE M60S SW.

ROCKIES UPR LOW WILL SHEAR OUT TO AN OPEN WAVE OVER THE HIGH PLAINS
THU-THU NGT. RIDGING ALOFT IN ADVANCE OF THIS SYSTEM SHOULD RESULT
IN CONTD DRY WX ACROSS OUR AREA THU... BUT BY THU NGT STALLED SFC
BOUNDARY OVER THE OH VALLEY IS EXPECTED TO LIFT NORTH IN RESPONSE
TO APCHG UPR TROF... PSBLY CAUSING SHOWERS/TSTMS IN OUR AREA.

UPR RIDGE WILL MOVE EAST OF THE AREA ON FRIDAY BUT RETURN OF
MOIST/UNSTABLE AIRMASS MAY ALLOW FOR SOME AFTN TSTMS TO DEVELOP. NRN
STREAM SHRTWV MOVG THROUGH ZONAL FLOW ACROSS CANADA IS EXPECTED TO
PUSH A CDFNT SOUTH INTO OUR CWA SATURDAY WHICH WILL LIKELY STALL
OVER THE AREA AS IT AWAITS PLAINS TROF AND ASSOCIATED SFC WAVE ALONG
THE FRONT TO MOVE THROUGH. THIS WILL KEEP STORM CHANCES THROUGH THE
WEEKEND... THOUGH CONDITIONS MAY DRY OUT/WARM UP ON LABOR DAY AS THE
SHRTWV MOVES EAST TO THE LWR GRTLKS AND ANOTHER SOMEWHAT STRONGER
SHRTWV/CDFNT MOVES EAST ACROSS THE PLAINS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 136 PM EDT TUE AUG 26 2014

LINE OF THUNDERSTORMS ASSOCIATED WITH SLOWLY ADVANCING COLD FRONT IS
CURRENTLY PUSHING THROUGH NORTHERN INDIANA. MODERATE INSTABILITY
WILL MAINTAIN THIS LINE OF STORMS AS IT PUSHES EASTWARD BUT LACK
OF SHEAR WILL KEEP CONVECTION DISORGANIZED THROUGH THE LATE
AFTERNOON. EXPECT A BROKEN LINE OF STORMS TO IMPACT KFWA AROUND
21Z. CONFIDENCE IN EXACT TIMING AND COVERAGE IS TOO LOW FOR A
PREVAILING THUNDER MENTION AT THIS TIME. VFR CONDITIONS EXPECTED
FOR TONIGHT AND INTO TOMORROW AS COLD/DRY AIR ADVECTION INCREASES
BEHIND EXITING FRONT. SOME MVFR BR POSSIBLE AROUND SUNRISE BUT
FORECAST SOUNDINGS ARE NOT OVERLY SUPPORTIVE AND WILL HOLD OFF ON
INCLUSION IN THE TAF AT THIS TIME.

&&

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

$$

SYNOPSIS...LOTHAMER
SHORT TERM...FISHER
LONG TERM...JT
AVIATION...AGD


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

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






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