Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 310020
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
820 PM EDT WED JUL 30 2014

.SYNOPSIS...
ISSUED AT 810 PM EDT WED JUL 30 2014

A SERIES OF WEAK DISTURBANCES ROTATING AROUND AN UPPER LEVEL LOW
WILL PROVIDE A CHANCE OF MAINLY AFTERNOON SHOWERS AND ISOLATED
THUNDERSTORMS THROUGH FRIDAY. TEMPERATURES WILL BEGIN TO MODERATE
BY THE WEEKEND.

&&

.UPDATE...
ISSUED AT 810 PM EDT WED JUL 30 2014

AN AREA OF SHOWERS PERSISTS THIS EVENING ACROSS NORTHEAST INDIANA
ALONG WEAK SFC TROUGH WHICH HAS BEEN ENHANCED BY LAKE BREEZE THIS
AFTERNOON. MID/UPPER LEVEL FORCING WITH THE ASSOCIATED SHORT
WAVE...HAS EXITED WELL EAST OF THE AREA HOWEVER...AND THIS SHOULD
CONTINUE TO LIMIT COVERAGE OF SHOWERS OVER THE NEXT FEW HOURS.
WANING INSTABILITY SHOULD LIMIT ANY TS AND HAVE UPDATED FORECAST
TO GO WITH MAINLY ISOLATED SHOWERS ACROSS FAR SOUTHEAST PORTIONS
OF THE AREA THIS EVENING. ADDITIONAL CONVECTION HAS DEVELOPED
ACROSS NORTHWEST WISCONSIN EARLY THIS EVENING IN ASSOCIATION WITH
NEXT VORT MAX ROTATING AROUND PARENT UPPER LOW. WITH BULK OF THIS
FORCING DROPPING SOUTHEAST INTO THE NORTHERN/CENTRAL GREAT
LAKES...ANY SHOWERS REMAINDER OF THE EVENING AND OVERNIGHT SHOULD
REMAIN TO THE NORTHWEST/NORTH OF THE LOCAL AREA. UPDATED FORECAST
SENT TO REMOVE EVENING TS AND TO SLIGHTLY TWEAK POPS TO ACCOUNT
FOR CURRENT TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 328 PM EDT WED JUL 30 2014

WIDELY SCATTERED SHOWERS AND STORMS WILL CONTINUE TO AFFECT MUCH OF
THE AREA INTO EARLY EVENING AWAY FROM THE LAKE SHADOW THAT HAS ONCE
AGAIN WORKED WELL INLAND. BY MID EVENING SKIES WILL CLEAR WITH QUIET
CONDITIONS RETURNING.

UPPER LOW WILL FINALLY BEGIN TO PULL AWAY LATER TONIGHT INTO
THURSDAY TAKING THE CORE OF THE COLDEST AIR WITH IT. THAT BEING SAID
ANOTHER WEAK DISTURBANCE WILL STILL MOVE THROUGH THE REGION WITH
ENOUGH LINGERING MOISTURE AND COLD AIR ALOFT TO ALLOW FOR ISOLATED
SHOWERS AND STORMS...MAINLY NORTHEAST DURING THE AFTERNOON HOURS
WHERE INSTABILITY WILL PEAK IN THE 500 TO 1000 J/KG OF SURFACE BASED
CAPE. HIGHS SHOULD EDGE A DEGREE OR 2 WARMER THAN TODAY WITH
READINGS IN THE MID TO UPPER 70S.

&&

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 328 PM EDT WED JUL 30 2014

UPR LOW NEAR JAMES BAY EXPECTED TO MOVE SLOWLY EAST THU NIGHT...
HWVR AN UPR LEVEL TROF SHOULD LINGER ACROSS THE GRTLKS/OH VALLEY
INTO FRIDAY... MOVG SLOWLY EAST OVER THE WEEKEND. WK SHRTWVS
EXPECTED TO MOVE THROUGH THE UPR TROF AND ACROSS OUR CWA BOTH
FRI/SAT WITH WK/MOD DIURNAL INSTABILITY RESULTING IN A CHC OF TSTMS.
BETTER CHC LOOKS TO BE FRI WHEN A SFC REFLECTION INVERTED TROF
SLIDES EAST ACROSS THE AREA. WK N-NE LOW LEVEL FLOW EXPECTED IN THE
WAKE OF THE INVERTED TROF SATURDAY AS SFC HIGH PRESSURE BUILDS OVER
THE UPR GRTLKS. A CHC OF SHOWERS/TSTMS STILL WARRANTED FOR SATURDAY
AS LINGERING LOW LEVEL MOISTURE SHOULD AGAIN RESULT IN WK/MOD
DIURNAL INSTABILITY WITH LAKE BREEZE BOUNDARIES MEANDERING THROUGH
THE AREA IN THE AFTN TO ALSO FOCUS CONVECTION. GIVEN WK STEERING
FLOW AND LIMITED MOISTURE/INSTABILITY BOTH DAYS... EXPECT COVERAGE
OF SHOWERS/STORMS WILL BE 30-40% AT BEST.

UPR LEVEL TROF EXPECTED TO MOVE EAST ACROSS OH SUNDAY SHIFTING
BETTER FORCING/INSTABILITY TO EAST OF OUR CWA. SHRTWV MOVG ACROSS
SRN CANADA EARLY NEXT WEEK SHOULD PUSH A SLOW MOVG BACKDOOR CDFNT
SOUTH INTO OUR AREA BY TUE. MOISTURE POOLING ALONG THE FRONT MAY
ALLOW AFTN TSTMS TO FORM OVER THE AREA TUE. WRN RIDGE EXPECTED TO
CONT TO FLATTEN AS NEXT SHRTWV MOVES OVER TOP AND ACROSS THE PLAINS
WED. THIS MAY RESULT IN SCT TSTMS ALONG/NORTH OF THE STALLED SFC
BOUNDARY... MAINLY OVER NRN PORTIONS OF THE CWA.

TEMPS EXPECTED TO REMAIN A BIT BLO NORMAL THROUGH SATURDAY... THEN WARM
TO AT OR SLIGHTLY ABOVE NORMAL EARLY NEXT WEEK AS MODEST UPR RIDGING
BUILDS INTO THE AREA. THESE WARMER TEMPS SHOULD PERSIST ACROSS SRN
PORTIONS OF THE CWA AT LEAST INTO TUE... WITH WK CAA BEHIND
BACKDOOR CDFNT PRBLY IMPACTING AT LEAST THE N-NE PORTION OF THE
CWA BY WED.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 810 PM EDT WED JUL 30 2014

COMBINATION OF WEAK SFC TROUGH/NORTHERLY FLOW ASSOCIATED WITH
DECAYING LAKE BREEZE AND WEAK DIURNAL INSTABILITY WAS SUFFICIENT FOR
ISOLATED SHOWERS AND THUNDERSTORMS ACROSS NORTHERN INDIANA...ALTHOUGH
ADDITIONAL ISOLATED SHOWERS THIS EVENING SHOULD REMAIN SOUTH OF
KFWA. OTHERWISE...VFR CONDITIONS TO PERSIST WITH ANOTHER UPSTREAM
VORT MAX DROPPING INTO THE NORTHERN GREAT LAKES EVENING. TRACK OF
THIS VORT SHOULD FAVOR ADDITIONAL PRECIP CHANCES TONIGHT WELL
NORTHWEST/NORTH OF TERMINALS. MID/UPPER LEVEL FORCING APPEARS TO
BE QUITE WEAK TOMORROW. LOW LEVEL HEIGHT GRADIENT IS ALSO EXPECTED
TO BE SLIGHTLY STRONGER WHICH LENDS TO LOWER CONFIDENCE IN LAKE
BREEZE DEVELOPMENT. WEAK LAKE INFLUENCE STILL POSSIBLE
TOMORROW...MORE LIKELY RESULTING IN WESTERLY WINDS DURING
AFTERNOON AT KSBN AFTER SYNOPTIC MODIFICATION. THIS COULD YIELD
AN ASSOCIATED WEAK SFC CONVERGENCE AXIS THAT MAY BE FOCUS FOR ISOLD
AFTERNOON SHOWERS/STORMS. WILL OMIT ANY MENTION OF PRECIP AT THIS
FORECAST DISTANCE GIVEN EXPECTED LOW COVERAGE...AND LOW CONFIDENCE
OF OCCURENCE AT TERMINALS.

&&

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

$$

UPDATE...MARSILI
SYNOPSIS...MARSILI
SHORT TERM...FISHER
LONG TERM...JT
AVIATION...MARSILI


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