Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 020742
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
342 AM EDT WED SEP 2 2015

.SYNOPSIS...
ISSUED AT 145 AM EDT WED SEP 2 2015

AN UPPER LEVEL DISTURBANCE WILL SLOWLY EXIT THE REGION THROUGH
WEDNESDAY AFTERNOON. AN ISOLATED SHOWER OR THUNDERSTORM IS
POSSIBLE THROUGH THIS AFTERNOON...BUT OTHERWISE HOT AND HUMID
CONDITIONS WILL PERSIST THROUGH MUCH OF THE REMAINDER OF THE WEEK.
HIGH TEMPERATURES THIS AFTERNOON WILL REACH INTO THE UPPER 80S TO
AROUND 90. LOW TEMPERATURES TONIGHT WILL DROP BACK INTO THE MID TO
UPPER 60S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 341 AM EDT WED SEP 2 2015

UPPER LEVEL LOW CONTINUES TO SLOWLY EXIT THE AREA THIS
MORNING...DRIFTING ACROSS SOUTHWEST OHIO AS OF 07Z. BROAD 850-700
HPA WARM ADVECTION WILL CONTINUE EARLY THIS MORNING ACROSS MUCH OF
LOWER MICHIGAN/NORTHERN INDIANA/NORTHWEST OHIO IN ASSOCIATION WITH
THICKNESS MINIMUM ACCOMPANYING DEPARTING UPPER LOW. DESPITE THIS
STRONGER ISENTROPIC UPGLIDE OVERSPREADING WESTERN PORTIONS OF THE
AREA EARLIER IN THE OVERNIGHT HOURS...ELEVATED SHOWERS HAVE HAD A
DIFFICULT TIME FORMING...POSSIBLY IN PART DUE TO FAIRLY STRONG
DNVA WITH DEPARTING UPPER VORT MAX. SHOWERS ARE BEGINNING TO FILL
IN A BIT ACROSS LOWER MICHIGAN HOWEVER...AND EXPECTING ISOLATED
SHOWERS TO CONTINUE TO DEVELOP SOUTHWARD ACROSS NORTHEAST
INDIANA/NORTHWEST OHIO THROUGH THE EARLY MORNING HOURS AS A POCKET
OF SLIGHTLY ENHANCED LOW LEVEL MOISTURE/ELEVATED INSTABILITY
SHIFTS INTO NORTHWEST OHIO TOWARD 12Z. STRONGEST ISENTROPIC
UPGLIDE SHOULD EVENTUALLY FOCUS ACROSS SOUTHEAST THIRD OF THE AREA
LATER THIS MORNING/AFTERNOON...AND CURRENT THINKING IS BEST CHANCE
OF ISOLATED CONVECTION WOULD BE ACROSS THE SOUTHEAST.
HOWEVER...WITH BROAD ISENTROPIC UPGLIDE AND DIURNAL
INSTABILITY...HAVE MAINTAINED IDEA OF PREVIOUS FORECAST IN SLIGHT
CHANCE POPS ACROSS APPROXIMATELY EASTERN HALF OF THE AREA TODAY.
SHEAR PROFILES REMAIN VERY WEAK TODAY WITH NOT MUCH CONVECTIVE
ORGANIZATION EXPECTED...WITH STILL A POSSIBILITY OF ISOLATED
HEAVIER DOWNPOURS GIVEN SMALL MAGNITUDES TO STORM MOTIONS. ANOTHER
UNSEASONABLY WARM DAY IS IN STORE...EVEN PERHAPS A FEW DEGREES
WARMER THAN YESTERDAY IN SPOTS DEPENDING ON EXTENT OF ANY
CONVECTIVE CLOUD DEBRIS.

FORECAST FOR TONIGHT SOMEWHAT MUDDLED GIVEN INITIALLY WEAK MID/UPPER
LEVEL FORCING ACROSS THE AREA AND CONTINUED BROAD/WEAK ISENTROPIC
ASCENT. HARD TO DISCOUNT ISOLATED SHOWER REALLY ANY TIME
TONIGHT...BUT BEST CHANCE APPEARS TO BE ACROSS THE NORTHWEST LATE IN
THE NIGHT AS THE NEXT UPPER LEVEL SHORT WAVE APPROACHES FROM THE
NORTHERN PLAINS. HAVE ADDED SLIGHT CHANCE TSRA POPS ACROSS THE
NORTHWEST AFTER 09Z. OTHERWISE...ANOTHER MILD NIGHT IN STORE WITH
LOWS GENERALLY IN THE UPPER 60S.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 341 AM EDT WED SEP 2 2015

ABOVE NORMAL TEMPERATURES AND MAINLY DRY CONDITIONS WILL REMAIN THE
STORY THROUGH LABOR DAY AS AN EXPANSIVE UPPER RIDGE BUILDS ACROSS
THE EASTERN US/SE CANADA. WITH THAT SAID STILL SEVERAL (ALBEIT LOW)
CHANCES FOR ISO-SCT PRECIPITATION GIVEN LACK OF SIGNIFICANT CAPPING
AND ELEVATED SFC DEWPOINTS SUPPORTING MODEST INSTABILITY/LIMITED CIN
FOR THE AFTERNOON HOURS EACH DAY. BEST CHANCES APPEAR TO BE ON
THURSDAY AS A DISJOINTED/WEAK SHORTWAVE DROPS INTO THE LOWER LAKES
ON THE NORTHEAST PERIPHERY OF BUILDING RIDGE...ALTHOUGH ISOLATED
CONVECTION ALSO POSSIBLE WITH THE HEATING OF THE DAY INTO FRIDAY-
SATURDAY AS THIS WEAKNESS IN THE HEIGHT FIELD AND ATTENDANT ILL-
DEFINED SFC TROUGH STALL SOMEWHERE IN THE VICINITY BENEATH BUILDING
RIDGE.

SLIGHTLY DRIER AIR LOOKS TO FILTER IN ON EITHER SATURDAY OR
SUNDAY...WITH SUNDAY INTO MONDAY MORNING DRY WITH RIDGING IN COMMAND
BOTH ALOFT AND AT THE SFC. A VIGOROUS SHORTWAVE LIFTING OUT OF THE
PAC NW/NRN ROCKIES NORTHEAST INTO SOUTH-CENTRAL CANADA WILL ACT TO
FLATTEN THE RIDGE AND SEND A SLOWING FRONTAL BOUNDARY AND RENEWED
STORM CHANCES (AND COOLER TEMPS) INTO THE LOCAL AREA BY MONDAY NIGHT-
TUESDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 145 AM EDT WED SEP 2 2015

WATER VAPOR IMAGERY EARLY THIS MORNING INDICATES THE CONTINUED
SLOW EASTWARD PROGRESSION OF OLD VORT MAX WHICH HAS RESIDED ACROSS
THE REGION THE PAST FEW DAYS. WHILE FORCING WITH THIS WAVE IS
MIGRATING EAST OF THE AREA...BROAD ISENTROPIC ASCENT IN THE WAKE
OF THIS WAVE MAY BE ENOUGH TO GENERATE AN ISOLATED SHOWER OR
THUNDERSTORM OVERNIGHT. VERY LIMITED COVERAGE (IF OCCURS)
CONTINUES TO PRECLUDE MENTION IN TERMINAL FORECASTS. FAVORED AREA
OF WEAK ISENTROPIC FORCING SHOULD SHIFT INTO NORTHEAST INDIANA
LATER TODAY...BUT AGAIN DIFFICULT AT THIS TIME TO HAVE ANY
CONFIDENCE FOR TAF INCLUSION GIVEN EXPECTED LIMITED COVERAGE. FOG
POTENTIAL SEEMS TO BE LIMITED FOR TONIGHT AND NO CHANGE TO TEMPO
MVFR VSBYS FOR TERMINALS FOR A BRIEF TIME EARLY THIS MORNING FROM
10-12Z. OTHERWISE...SFC ANTICYCLONE SINKING SOUTH OF THE AREA
SHOULD PROMOTE WESTERLY WINDS AROUND 10 KNOTS THIS AFTERNOON
BACKING LIGHT SOUTHWEST FOR TONIGHT.

&&

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

$$

SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...STEINWEDEL
AVIATION...MARSILI


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