Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 250819
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
419 AM EDT MON MAY 25 2015

.SYNOPSIS...
ISSUED AT 406 AM EDT MON MAY 25 2015

WARM WEATHER WILL PREVAIL THIS WEEK WITH A CHANCE FOR SHOWERS
TODAY AS AN UPPER LEVEL TROF LIFTS NORTH. THUNDERSTORMS WILL BE
LIKELY BY LATE TUESDAY AS AN UPPER LEVEL DISTURBANCE MOVES ACROSS
THE AREA. MORE STORMS ARE POSSIBLE LATE THIS WEEK AND THROUGH THIS
COMING WEEKEND AS AN UPPER LEVEL SYSTEM MOVES EAST. 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 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 154 AM EDT MON MAY 25 2015

PRIMARILY VFR CONDS THIS PD. LLWS CONCERN REMAINS INTACT IN
DEFERENCE TO LLJ IN PLACE THIS MORNING. OTRWS KEPT VCSH
MENTION/TIMING INVOF KSBN LTR THIS MORNING UNDER THE ASSUMPTION
UPSTREAM ACTIVITY ACRS ERN IL HOLDS TOGETHER. OTRWS POOR LL MSTR RTN
UNDERNEATH ENCROCHING DRYSLOT THIS AFTN OBVIATES ANY FURTHER
SENSIBLE WX MENTION FOR THE VALID TAF PD.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...BEACH HAZARDS STATEMENT FROM 8 AM EDT THIS MORNING THROUGH THIS
     EVENING FOR MIZ077.

OH...NONE.
LM...GALE WARNING FROM 10 AM THIS MORNING TO 4 PM EDT THIS AFTERNOON
     FOR LMZ043-046.

&&

$$

SYNOPSIS...SKIPPER
SHORT TERM...T
LONG TERM...SKIPPER
AVIATION...T


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