Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 251721
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
121 PM EDT MON MAY 25 2015

.SYNOPSIS...
ISSUED AT 1135 AM EDT MON MAY 25 2015

SCATTERED SHOWERS WILL DIMINISH LATER THIS AFTERNOON AS AN UPPER
LEVEL DISTURBANCE SWEEPS NORTHEAST THROUGH THE AREA.
OTHERWISE...WINDY CONDITIONS WILL CONTINUE THIS AFTERNOON WITH
SOME DECREASE IN CLOUDS EXPECTED FOR MID TO LATE AFTERNOON.
THUNDERSTORMS WILL BECOME MORE LIKELY BY LATE TUESDAY AS ANOTHER
UPPER LEVEL DISTURBANCE MOVES ACROSS THE AREA. MORE STORMS ARE
POSSIBLE LATE THIS WEEK AND THROUGH THIS COMING WEEKEND. HIGHS
THIS WEEK SHOULD BE MAINLY IN THE UPPER 70S TO MID 80S WITH LOWS
AROUND 60 TO THE MID 60S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 406 AM EDT MON MAY 25 2015

SW OVR SE KS THIS MORNING WILL SHEAR NEWD THROUGH WI THIS AFTN WHILE
SIG MIDLVL DRYSLOT ADVTS NEWD UP ACRS THE CWA THIS AFTN. INBTWN LL
THETA-E BURST ALG NOSE OF LLJ ABT THE ONLY FORCING MECHANISM OF NOTE
NR TERM YET RUNS COUNTER TO WWD DISPLACEMENT OF ATTENDANT UPR JET
STREAK NOT TO MENTION BTR SFC BASED MSTR TRANSPORT. HWVR POCKET OF
MORE VIGOROUS SHRA OVR WRN KY ERLY THIS MORNING XPCD TO CARRY NWD
THROUGH NW CWA THROUGH MID MORNING WHERE HIGHEST POPS WERE CONFINED.
OTRWS TRUNCATED POPS FURTHER THIS AFTN AND DROPPED ENTIRELY
OVERNIGHT.

PRIMARY ITEM OF SIGNIFICANCE WILL BE ESCALATION OF GRADIENT WINDS
LTR THIS MORNING THROUGH THIS AFTN. INCOHERENT UPSTREAM CLD MASS
STEMMING FM GENERAL DECAYING/BKN BAND OF SHRA THROUGH CNTRL/SRN IL
SUGGESTS POCKETS OF INSOLATION WILL DVLP BY MID MORNING PRIOR TO
ARRIVAL OF STG SUBSIDENCE ASSOCD/W DRYSLOT THIS AFT. GIVEN SLOW
EXIT/DISSIPATION OF LLJ SOME CONCERN EXISTS W/POTENTIAL MOMENTUM
TRANSFER THROUGH AN INCREASINGLY WELL MIXED AND DEEPENING BNDRY LYR.
00Z GUIDANCE CONSENSUS PORTENTS SFC GUSTS TO 35KTS THIS AFTN
W/VARIOUS MIX DOWN TOOLS INDICATING 40KT GUSTS PSBL. HWVR MORE
RECENT UPSTREAM SHRA DVLPMNT THROUGH FAR WRN KY AND MORE VIGOROUS
CLD DVLPMNT THERE MAY SEDATE MORE RAPID HEATING THROUGH MORNING TIED
TO STGR FLW ALOFT AND CURTAIL THIS POTENTIAL. FOR NOW WILL JUST BUMP
WINDS HIGHER YET HOLD BLO ADVISORY CRITERIA AND PASS ON TO NXT SHIFT
TO MONITOR.

&&

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 406 AM EDT MON MAY 25 2015

THE ONGOING FORECAST FOR TUESDAY INTO TUESDAY NIGHT APPEARS ON TRACK
WITH THUNDERSTORMS BECOMING LIKELY BY LATE TUESDAY. NCEP MODELS AND
THE ECMWF CONTINUE TO INDICATE A SHORT WAVE TROF EJECTING NORTHEAST
ACROSS THE MIDWEST INTO NORTHERN INDIANA. THERMAL AND WIND PROFILES
INDICATE STORMS COULD BECOME MARGINALLY SEVERE WITH DAYTIME HEATING.
HOWEVER...FACTORS LIMITING SEVERE POTENTIAL INCLUDE FAIRLY STABLE
MID LEVEL LAPSE RATES WITH GENERALLY TALL BUT THIN CAPES PER 00Z GFS
BUFKIT AND MARGINAL WIND SHEAR. THUNDERSTORMS WILL LIKELY PRODUCE
HEAVY RAIN WITH LOCAL FLOODING POSSIBLE GIVEN HIGH PRECIPITABLE
WATER VALUES AND A FAIRLY DEEP WARM CLOUD LAYER. FOR THE REST OF THE
PERIOD...KEPT WEDNESDAY NIGHT THROUGH THURSDAY NIGHT DRY. STORM
CHANCES INCREASE ONCE AGAIN LATE IN THE WEEK AS A SLOW MOVING UPPER
LEVEL SYSTEM FROM THE WEST IN THE SOUTHERN STREAM WILL COME CLOSE TO
PHASING WITH A NORTHERN SHORT WAVE TROF DROPPING SOUTH OUT OF
CENTRAL CANADA. THERE WAS STILL A LOT OF UNCERTAINTY HOW THE COLD
FRONT ASSOCIATED WITH THE NORTHERN STREAM SYSTEM WILL INTERACT THIS
WEEKEND WITH THE SHORT WAVE OF THE SOUTHERN SYSTEM. FOR NOW...GIVEN
THIS UNCERTAINTY...KEPT MAINLY MID/CHANCE RANGE FOR SHOWERS AND
STORMS FROM FRIDAY THROUGH SUNDAY. AS FOR TEMPERATURES...UPPER LEVEL
RIDGING EXTENDING NORTHEAST FROM THE SUB TROPICAL RIDGE OVER THE
SOUTHEAST CONUS COULD REALLY ALLOW TEMPS TO WARM BETWEEN SYSTEMS.
CAN NOT RULE OUT THE GFS FCST MEX HIGH OF 90 DEGREES FOR LIMA ON
FRIDAY SO RAISED HIGHS TO 82 TO 86 FRIDAY WITH 850 MB TEMPS RISING
TO NEAR 17C. HIGHS SHOULD BY ABLE TO CLIMB TO AT LEAST 80 DEGREES
EACH DAY FROM TUESDAY THROUGH FRIDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 120 PM EDT MON MAY 25 2015

CONDITIONS WILL CONTINUE TO HOVER IN LOW END VFR CATEGORY THROUGH
THE LATE AFTERNOON AS A SHORTWAVE LIFTS ACROSS THE REGION. A FEW
SCT SHOWERS ASSOCIATED WITH THIS FEATURE ARE ALSO CURRENTLY MOVING
ACROSS NORTHERN INDIANA. THESE SHOWERS WILL EXIT DURING THE NEXT
1-2 HOURS BUT UPSTREAM OBS STILL SHOW SPORADIC MVFR STRATOCU
THROUGH WESTERN ILLINOIS. THIS LOW LEVEL MOISTURE WILL LIKELY NOT
SCATTER OUT UNTIL LATER THIS EVENING. MAINLY VFR CONDITIONS
EXPECTED OVERNIGHT BUT NEXT WAVE WILL BE QUICKLY APPROACHING.
INCREASING LOW LEVEL MOISTURE AND BOUNDARY LAYER COOLING COULD
LEAD TO SOME FUEL ALTERNATE STRATUS BY EARLY TOMORROW MORNING PER
LATEST GFS AND NAM FORECAST SOUNDINGS/MOS GUIDANCE. WILL HOLD WITH
HIGH END MVFR FOR NOW AND LET LATER SHIFTS ADJUST AS NECESSARY.
SHOWERS AND THUNDERSTORMS ALSO POSSIBLE BY THE VERY END OF THIS
TAF PERIOD.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR MIZ077.

OH...NONE.
LM...GALE WARNING UNTIL 4 PM EDT THIS AFTERNOON FOR LMZ043-046.

&&

$$

SYNOPSIS...MARSILI/SKIPPER
SHORT TERM...T
LONG TERM...SKIPPER
AVIATION...AGD


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