Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 042247
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
647 PM EDT MON MAY 4 2015

.SYNOPSIS...
ISSUED AT 1149 AM EDT MON MAY 4 2015

A FRONT WILL UNDULATE ACROSS THE AREA THROUGH TUESDAY...AND BE
ACCOMPANIED BY SHOWERS AND THUNDERSTORMS. AFTER THAT...TEMPERATURES
WILL WARM MUCH ABOVE NORMAL DURING THE SECOND HALF OF THE WEEK
WITH HIGHS REACHING THE 80S.

&&

.UPDATE...
ISSUED AT 646 PM EDT MON MAY 4 2015

LOWERED POPS AND DROPPED THUNDER MENTION (EXCEPT FOR FAR SOUTHERN
ZONES) THROUGH THE EARLY MORNING HOURS WITH WEAKENING MULTICELL
CLUSTERS TO REMAIN FOCUSED JUST SSW OF THE LOCAL AREA ALONG
LEFTOVER COMPOSITE OUTFLOW/INSTABILITY GRADIENT. ONLY MINOR
CHANGES OTHERWISE WITH BETTER RAIN/THUNDER CHANCES STILL ON TRACK
FOR LATER TONIGHT/TUE AM WITH MCS/MCV REMNANTS.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 239 PM EDT MON MAY 4 2015

KIWX RADAR AND LATEST SURFACE ANALYSIS INDICATING REMNANTS OF
SHOWERS HAS EXITED THE AREA AS FRONTAL BOUNDARY NOW SINKING DOWN
INTO NORTHERN CWA. 17Z MESOANALYSIS INDICATING SBCAPES HAVE
REBOUNDED TO 1500J/KG ACROSS CENTRAL ILLINOIS SUGGESTING WE STILL
MAY SEE SOME AIRMASS RECOVERY IN THE SOUTH BY LATE AFTERNOON/EARLY
EVENING SO WILL KEEP CHANCE POPS GOING THERE. MAIN FOCUS WILL BE FOR
CONVECTIVE REDEVELOPMENT OUT WEST IN THE PRESENCE OF BETTER
DYNAMICS. WATER VAPOR IMAGERY SHOWING SHORT WAVE ENERGY MOVING UP
ALONG THE BACKSIDE OF UPPER RIDGE AND WILL COINCIDE WITH AXIS OF
THETAE RIDGE AND EFFECTIVE SHEAR VALUES AROUND 50KT. HIRES GUIDANCE
INDICATING THIS WILL EVOLVE INTO NOCTURNAL MCS AND PROPAGATE
EASTWARD ALONG STALLED FRONTAL BOUNDARY TONIGHT. BASED ON THIS
SCENARIO WILL KEEP WINDOW OF LIKELY POPS GOING AFTER 06Z IN
ANTICIPATION OF MCS ARRIVAL. FRONTAL BOUNDARY THEN LIFTS BACK
NORTHWARD ON TUESDAY AND WILL FOCUS BEST CHANCES FOR PRECIP IN THE
NORTHERN HALF OF THE CWA...BUT ALL HINGES ON HOW OVERNIGHT
CONVECTION EVOLVES SO WILL KEEP EVERYTHING IN CHANCE RANGE FOR NOW.
EXPECT TEMPS IN 55-60 RANGE FOR LOWS TONIGHT WHILE FRONTAL BOUNDARY
IS EXPECTED TO PRODUCE STRONG GRADIENT ACROSS THE FORECAST AREA ON
TUESDAY WITH UPPER 70S IN THE FAR SOUTH TO MID 60S IN THE NORTH.

&&

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 239 PM EDT MON MAY 4 2015

STOUT MID LVL RIDGE DVLPMNT XPCD DOWNSTREAM OF WRN US TROUGHING THIS
PD W/MUCH ABV NORMAL TEMPS AND GENERALLY DRY UNTIL LT PD.

MUCH SLWR 12Z MODEL CONSENSUS OF NEWD EJECTION OF FOUR CORNERS
IMPULSE LT NXT WEEKEND LOOKS IDEAL ESP IN LIGHT OF FLW SEPARATION
ACRS THE WRN US AND COMMON MODEL BIASES. THUS DOWNPLAYED POPS FRI
AFTN THROUGH SUN IN REFLECTION OF GENERAL POOR SYNOPTIC SPRT HERE
AND LACKLUSTER MOISTENING EWD OF THE MS RVR. AT SOME POINT NO DOUBT
UPSTREAM CONV EVOLUTION AND/OR PIECEMEAL EJECTION OF WRN ENERGY WILL
AUGMENT MUCH HIGHER MESOSCALE FORCING AT TIMES HWVR BASED ON GROSS
SPECTRAL SOLUTION SCOPE...THAT DOES NOT SEEM PLAUSIBLE UNTIL FRI
NIGHT AT THE EARLIEST AND MOST LIKELY LT SAT AND AGAIN ON SUN.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 646 PM EDT MON MAY 4 2015

MAINLY DRY/VFR CONDITIONS ARE EXPECTED THROUGH THE EARLY MORNING
HOURS AS CONVECTION REMAINS FOCUSED SOUTH OF THE AREA ALONG
LEFTOVER COMPOSITE OUTFLOW ACROSS CENTRAL IN/IL. CONVECTIVELY
ENHANCED SHORTWAVE WILL LIKELY BRING WIDESPREAD SHOWERS/EMBEDDED
THUNDER AND FLIGHT RESTRICTIONS BACK INTO THE REGION LATER TONIGHT
INTO TUESDAY MORNING AS IT INTERACTS WITH PRIMARY FRONTAL BOUNDARY
DRAPED ACROSS NORTHERN IL/IN.

&&

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

$$

UPDATE...STEINWEDEL
SYNOPSIS...SKIPPER
SHORT TERM...LOGSDON
LONG TERM...T
AVIATION...STEINWEDEL


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