Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 291924
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
324 PM EDT FRI AUG 29 2014

.SYNOPSIS...
ISSUED AT 323 PM EDT FRI AUG 29 2014

A WARM FRONT WILL LIFT NORTHEAST INTO THE AREA TODAY INTO THIS
EVENING BRINGING INCREASING CHANCES FOR SHOWERS AND
THUNDERSTORMS...ESPECIALLY LATE THIS AFTERNOON AND EVENING ACROSS
NORTHWEST INDIANA AND SOUTHWEST LOWER MICHIGAN. LOWS TONIGHT WILL
FALL BACK INTO THE 60S.

SATURDAY WILL FEATURE BETTER CHANCES FOR THUNDERSTORMS AND
LOCALLY HEAVY RAINFALL AS A LOW PRESSURE SYSTEM TRACKS INTO THE
GREAT LAKES REGION.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 323 PM EDT FRI AUG 29 2014

WMFNT MAKING QUICK PROGRESS NWD THIS AFTN IN ASSOCN/W SW TROUGH AND
ATTENDANT SFC CYCLONE LIFTING NEWD OUT OF THE PLAINS. BROAD BELT OF
LL MSTR FLUX TIED TO LLJ WITHIN THETA-E RIDGE LEADING TO AN
EXPANDING AREA OF SHRA/EMBEDDED TSRA ACRS WRN ZONES EXTENDING SWWD
INTO ERN IL/WRN IN AND XPC THIS WILL CONT TO GRAVITATE N/NEWD
THROUGH THIS AFTN. SERN HALF THOUGH XPCD TO REMAIN DRY GIVEN
INFLUENCE OF WRN PERIPHERY OF RETREATING CONTINENTAL RIDGE AND POOR
EWD MSTR FLUX BOUND.

OTRWS W/WMFNT LIFTING THROUGH THIS EVENING DO NOT SEE MUCH OF AN
APPRECIABLE FOCUS SANS FAR NW ZONES FOR ANYTHING MORE THAN A
THRESHOLD LWR BOUND SLGT CHC POP MENTION. ON SAT WARM SECTOR IS
FULLY ENTRENCHED ACRS CWA ALG W/A VRY MOIST AIRMASS. DIURNAL HEATING
SHLD FOSTER SIG INSTABILITY BY AFTN AND W/SRN EDGE OF HGT FALLS IN
ASSOCN/W EJECTING PLAINS SW AND APCHG SFC FNTL ZONE WILL KEEP
W/PRIOR LIKELY POPS ALTHOUGH DID ADD SOME TEMPORAL DETAIL TO SAT
MORNING. SOME LOW RISK FOR SEVERE (DAMAGING WINDS) PER MODEST 0-6KM
BULK SHEAR NR 30-35KTS WHICH COMBINED W/PWATS NR 2 INCHES SUGGESTIVE
OF LOCAL MASS LOADING AND A PULSE SVR THREAT. MUCH WARMER W/LOW TO
MID 80S W-E ACRS CWA.

&&

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 323 PM EDT FRI AUG 29 2014

MAIN FOCUS IN LONG TERM REMAINS ON TIMING OF PRECIP CHANCES AND
POTENTIAL FOR ADDITIONAL HEAVY RAINFALL. UPPER TROF AND ASSOC SFC
BOUNDARY WILL BE MOVING ACROSS THE AREA SATURDAY NIGHT WITH RAIN
CHANCES CONTINUING THRU THE OVERNIGHT HOURS. AS MENTIONED BY SEVERAL
PREVIOUS SHIFTS...LOCALIZED HEAVY RAINFALL REMAINS A THREAT AS
IMPRESSIVE GULF MOISTURE TRANSPORT CONTINUES INTO THE AREA (PWATS IN
THE 1.7 TO 2 INCH RANGE WHICH IS NEAR 99TH PERCENTILE FOR THIS TIME
OF YEAR). SYSTEM WILL EXIT DURING THE DAY SUNDAY WITH PRECIP
TAPERING OFF FROM NW TO SE. LATEST 12Z MODEL RUNS IN AGREEMENT WITH
TIMING AND SUSPECT MOST OF SUNDAY WILL BE DRY...ESP IN NW SO HAVE
CUT POPS FURTHER ESP DURING THE AFTN/EVENING HOURS. BRIEF DRY PERIOD
LIKELY INTO THE START OF LABOR DAY AS FORCING DIMINISHES AND
SHORTWAVE RIDGE MOVES IN AHEAD OF NEXT SYSTEM.

AFOREMENTIONED SYSTEM PROGGED TO MOVE EAST FROM N PLAINS/S CANADA
AND SWING A COLD FRONT THRU THE AREA BY LATE AFTERNOON INTO THE
EVENING HOURS. LATEST NAM12 HAS SPED UP TIMING A FEW HOURS FROM
PREVIOUS RUN WITH FRONT MOVING THRU IN THE 21Z TIMEFRAME DURING PEAK
HEATING WITH MID LEVEL JET RAMPING UP. 12Z GFS/GEM/ECMWF REMAIN
SLOWER WITH FROPA IN THE 00-06Z TIMEFRAME. SVR THREAT REMAINS
CONDITIONAL AND WILL HINGE ON TIMING OF FROPA WHICH CAN BE FURTHER
NAILED DOWN AS LABOR DAY APPROACHES. LAPSE RATES WILL REMAIN MEAGER
WITH MARGINAL SHEAR ON THE ORDER OF 20-30 KTS BUT IF DESTABILIZATION
OCCURS...EXPECT MODERATE INSTABILITY WHICH MAY BE ENOUGH TO TRIGGER
A FEW STRONGER STORMS. AGAIN HEAVY RAINFALL WOULD BE BIGGEST THREAT
AS BOUNTIFUL MOISTURE TRANSPORT CONTINUES IN WARM SECTOR. PRECIP
WILL TAPER OFF DURING THE DAY TUESDAY AS FRONT DEPARTS AND STALLS
E-W INVOF OH VALLEY. MODELS DIFFER A BIT IN DETAILS AND PLACEMENT OF
SEVERAL SHORTWAVES RIDING ALONG BOUNDARY IN ZONAL UPPER LEVEL FLOW
THRU END OF PERIOD. FOR NOW HAVE KEPT WITH GOING DRY FORECAST FOR
WEDS THRU THURS AFTERNOON UNTIL DETAILS ARE BETTER RESOLVED.

TEMPERATURES WILL REMAIN NEAR NORMAL FOR THE START OF THE PERIOD
BEFORE RAMPING UP BY END OF THE WEEK WITH MORE MUGGY CONDITIONS
EXPECTED. HIGHS WILL GENERALLY BE IN THE LOW 80S THRU WEDS WITH MID
TO UPPER 80S POSSIBLE BY END OF THE WEEK. OVERNIGHT LOWS WILL BE IN
THE 60S.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 119 PM EDT FRI AUG 29 2014

VFR CONDS XPCD TO CONT THROUGH THE PD. HWVR LEADING EDGE OF MOD LL
THETA-E RIDGE WORKING EWD OUT OF IL ALG W/FVRBL LLJ LEADING TO A
RECENT UPTICK IN CONVN ACRS NW IN AND SUSPECT THIS WILL CONT THROUGH
MID AFTN NWD OF WMFNTL BNDRY MIXING NORTH THROUGH CNTRL IN/IL ATTM.
PREV AMENDMENT FOR KSBN COVERS THIS BUT WILL KEEP W/PRIOR DRY TAF
FCST AT KFWA WHICH LOOKS TO STILL RESIDE WITHIN LESS FVRBL WRN
PERIPHERY OF LL RIDGE AXIS AND W/MUCH WEAKER MASS FLUX XPCD THERE.
CANT ENTIRELY RULE AN ISOLD STORM THERE LTR THIS AFTN BUT ODDS ARE
AGAINST IT.


&&

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

$$

SYNOPSIS...T
SHORT TERM...T
LONG TERM...CEO
AVIATION...T


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