Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 310850
AFDIWX

AREA FORECAST DISCUSSION...CORRECTION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
449 AM EDT SUN AUG 31 2014

.SYNOPSIS...
ISSUED AT 1250 AM EDT SUN AUG 31 2014

SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL REMAIN POSSIBLE
MAINLY SOUTHEAST OF HIGHWAY 24 IN INDIANA AND OHIO THIS MORNING
ALONG A WEAK FRONTAL BOUNDARY. DRIER AIR WILL FILTER INTO THE AREA
LATER TODAY INTO TONIGHT AS HIGH PRESSURE BRIEFLY BUILDS INTO THE
GREAT LAKES REGION. A COLD FRONT WILL PUSH IN FROM THE WEST MONDAY
INTO MONDAY EVENING BRINGING RENEWED CHANCES FOR SHOWERS AND
THUNDERSTORMS. HIGHS WILL REACH INTO THE UPPER 70S TO LOW 80S
TODAY AND THE LOW TO MID 80S ON MONDAY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 444 AM EDT SUN AUG 31 2014

WEAK TRAILING SFC TROUGH/SHEAR AXIS FROM POTENT MID LEVEL
CIRCULATION TRANSLATING EAST THROUGH THE NORTHERN GREAT LAKES WILL
SINK SLOWLY SE THROUGH SOUTHEASTERN PORTIONS OF THE FA TODAY.
ISO-SCT SHOWERS/THUNDER MAY CONTINUE TO ACCOMPANY THIS WEAK
CONVERGENT BOUNDARY INTO THE AFTERNOON GIVEN AMPLE
MOISTURE/BUILDING INSTABILITY (850 MB DEWPOINTS TO 13-14C AND PWATS
1.7-1.8 INCHES)...AND WEAK DEFORMATION TIED TO AN APPROACHING MID MS
VALLEY UPPER TROUGH. PRONOUNCED MID LVL SUBSIDENCE/DRYING IN WAKE OF
THE NRN LAKES WAVE SHOULD KEEP NORTHWEST ZONES DRY THROUGH THE DAY
WITH SKIES EVENTUALLY TRENDING PARTLY CLOUDY. ANTICIPATE STUBBORN
BKN-OVC STRATOCUMULUS TO REMAIN LOCKED IN ELSEWHERE...WITH MOIST
BOUNDARY LAYER, DECAYING PRES GRADIENT NEAR SFC TROUGH, AND SOME
PARTIAL CLEARING POSSIBLY SUPPORTING SOME PATCHY FOG DEVELOPMENT
INTO NW IN/SW LOWER MI EARLY THIS MORNING.

TONIGHT...RIDGING BOTH ALOFT AND AT THE SFC WORKING EAST THROUGH THE
LOWER LAKES SHOULD ENSURE A DRY NIGHT OUTSIDE OF NONZERO CHC FOR AN
ISO SHOWER EARLY EVENING EASTERN HALF. OTHERWISE...PATTERN FAVORS
PATCHY FOG/STRATUS DEVELOPMENT OVERNIGHT GIVEN LIGHT WINDS AND MOIST
BL UNDER SUBSIDENCE/NOCTURNAL INVERSION.

&&

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 444 AM EDT SUN AUG 31 2014

PRIMARY FOCUS ON MONDAY HOLIDAY. VIGOROUS SHORTWAVE ENERGY PUSHING
EASTWARD THROUGH INTERMOUNTAIN WEST AT THIS TIME...ENTERING UPPER
MISSISSIPPI VALLEY/INTO WESTERN GREAT LAKES BY MONDAY AFTERNOON.
ANTICIPATE ANY ONGOING CONVECTION EARLY TO DECAY ACROSS THE
SOUTHWEST GREAT LAKES IN AM HOURS...AND PROVIDED SOME GREATER
TIME/SPACE DETAILS WITH RESPECT TO POP/WX...WITH EARLIEST
POTENTIAL/LOW PROBABILITIES FOR CONVECTIVE INITIATION NOT UNTIL
MIDDAY ALONG OUTFLOW BOUNDARY. STRONG SURFACE HEATING THROUGH WARM
SECTOR TO YIELD MODERATE 2500-3500 J/KG SBCAPE BY LATE AFTERNOON
ACROSS NORTHWEST CWA. SYNCHRONICITY OF MAX DESTABILIZATION WITH
ROBUST 50-60KT 7-6H JET SEGMENT PUSHING EWD THROUGH NORTHERN IL/SRN
WI INTO NWRN CWA LENDS CONCERN FOR POTENTIAL LATE AFTERNOON/EVENING
SEVERE EVENT. DEEP LAYER SHEAR VALUES ON ORDER OF 35-40 KTS WITH
DECENT LOW LEVEL VEERING COULD LEND SOME PREFRONTAL SUPERCELLULAR
ORGANIZATION WITH ASSOCIATED WIND/HAIL THREAT.....WITH NOTABLE
600-850 J/KG PER NAM IN HAIL GROWTH REGION...DESPITE FAIRLY HIGH
WETBULB ZERO HEIGHTS AROUND 13-13.5 KFT. ADDITIONAL SEVERE WIND
CONCERN TIED TO LINEAR/FRONTAL FOCUSED CONVECTION SPREADING EASTWARD
THROUGH THE EARLY NIGHT. ADDITIONAL CONCERN FOR HEAVY RAINFALL LATE
MONDAY NIGHT INTO TUESDAY WITH ENHANCED LOW LEVEL CONVERGENCE
ASSOCIATED WITH NORTHEASTWARD EJECTION OF FRONTAL WAVE FROM CENTRAL
PLAINS TOWARD ECNTL MO/CNTL IL. CWA COLLOCATED WITH DIVERGENT
QUADRANT OF UPPER LEVEL JET SEGMENT RAMPING TO 120 KTS FROM CNTL
LAKE MI TO NORTHERN LAKE HURON. HIGHEST PRECIP EFFICIENCY ACROSS
SOUTHEAST HALF OF CWA...THOUGH LACK OF CONFIDENCE IN ANY LATE
DAY2/EARLY DAY 3 MESOSCALE DETAILS PRECLUDE ANYTHING MORE THAN
GENERALIZED MENTION IN HWO ATTM. FRONTAL BOUNDARY TO SLOWLY LIE
SOUTHEAST INTO OHIO VALLEY WITH SLOW SCOUR OF LOW LEVEL MOISTURE
TUESDAY WARRANTS LINGERING MENTION ACROSS SOUTHERN/SOUTHEAST CWA
INTO AFTERNOON HOURS. SIGNIFICANTLY COOLER/DRIER MIDWEEK WITH
MODERATION THEREAFTER. FAVOR DRY THROUGH THURSDAY WITH ANY WARM
FRONTAL FOCUS WELL S-W OF CWA. SLOWED MOISTURE RETURN SLIGHTLY OVER
EAGER CONSENSUS BLEND WITH CAPPED ENVIRONMENT ANTICIPATED THU ACROSS
CWA. THEREAFTER CIRCUITOUS GOMEX FEED AND ANOTHER FRONTAL BOUNDARY
PUSHING ESEWD FROM UPPER MIDWEST INTO GREAT LAKES...THEN STALLING
E-W THROUGH SOUTHERN GREAT LAKES...HAVE LOW CHC/LONG DURATION TSRA
MENTION THU NIGHT INTO SAT.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1250 AM EDT SUN AUG 31 2014

HIGH BOUNDARY LAYER MOISTURE AND WEAK CONVERGENCE INVOF OF A SFC
TROUGH WILL ALLOW CIGS TO LOWER INTO MAINLY IFR-LOW MVFR THIS
MORNING. BROKEN/POORLY ORGANIZED CONVECTIVE LINE ALONG THIS SFC
TROUGH WILL SAG SLOWLY SSE INTO THE KFWA AREA THIS MORNING/EARLY
AFTERNOON. OPTED FOR A VCSH MENTION FOR NOW GIVEN UNCERTAINTY/WEAK
FORCING. PCPN SHOULD REMAIN SOUTH/EAST OF KSBN WITH POTENTIAL FOR
FOG/LIFR CONDITIONS TO FILL IN TOWARD DAYBREAK. CONDITIONS SHOULD
GRADUALLY IMPROVE TO VFR THIS AFTERNOON.

&&

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

$$

SYNOPSIS...STEINWEDEL
SHORT TERM...STEINWEDEL
LONG TERM...MURPHY
AVIATION...STEINWEDEL


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