Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 130444
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1244 AM EDT SUN APR 13 2014

.SYNOPSIS...
ISSUED AT 536 PM EDT SAT APR 12 2014

WARM CONDITIONS WILL CONTINUE INTO THE OVERNIGHT HOURS WITH LOW
TEMPERATURES IN THE UPPER 50S TO NEAR 60. HIGH TEMPERATURES WILL
RISE INTO THE MID 70S AGAIN ON SUNDAY. A STRONGER UPPER LEVEL
DISTURBANCE AND FRONTAL BOUNDARY WILL INCREASE THE CHANCES OF RAIN
AND SCATTERED THUNDERSTORMS ACROSS THE REGION SUNDAY NIGHT AND
MONDAY. CONDITIONS WILL TURN COOLER AND BLUSTERY EARLY NEXT WEEK
IN THE WAKE OF THIS FRONTAL SYSTEM.

&&

.UPDATE...
ISSUED AT 813 PM EDT SAT APR 12 2014

NO MAJOR CHANGES ANTICIPATED TO THE FORECAST TONIGHT. BROAD WARM
ADVECTION WILL CONTINUE TO SUPPORT SCATTERED/NUMEROUS SHOWERS AND
THUNDERSTORMS FOR AREAS MAINLY WEST AND NORTH OF THE LOCAL AREA
TONIGHT. RADAR IMAGERY/SFC OBS HAVE DEPICTED SLIGHT SOUTHWARD
DISPLACEMENT OF SFC BOUNDARY TO THE NORTH OF KALAMAZOO MICHIGAN
OVER PAST FEW HOURS AS A RESULT OF CONTINUED CONVECTION. LITTLE OF
ANY IMPETUS FOR MUCH ADDITIONAL SOUTHWARD DISPLACEMENT IS EXPECTED
THROUGH THE REMAINDER OF THE NIGHT...AND FAIRLY SHALLOW NATURE OF
THIS SFC BOUNDARY WOULD SUGGEST MINIMAL CHANCES OF ANY
SHOWER/THUNDERSTORM ACTIVITY MAKING IT AS FAR SOUTH AS FAR
SOUTHERN LOWER MICHIGAN. DID GO AHEAD AND REMOVE EARLY EVENING
SLIGHT CHANCE TSRA WORDING ACROSS FAR SOUTHWEST LOWER
MICHIGAN...AND HAVE MAINTAINED INHERITED DRY FORECAST FOR THE
OVERNIGHT HOURS WITH AXIS OF MORE PRONOUNCED LOW LEVEL MOISTURE
CONVERGENCE REMAINING FROM THE MID MS RIVER VALLEY NORTHEASTWARD
INTO WEST CENTRAL LOWER MICHIGAN.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 454 PM EDT SAT APR 12 2014

LOW PRES DVLPG ACRS WRN KS THIS AFTN WILL INTENSIFY AND LIFT NEWD
INTO ERN IA SUN AFTN. SFC BNDRY STRETCHED FM CNTRL LWR MI SWWD
THROUGH ERN IA WILL MOVE LTL AND XPC BULK OF SHRA/TSRA ACTIVITY TO
DVLP IN PROXIMITY TO FNTL ZONE TONIGHT. POSITION OF LL THETA-E RIDGE
PRETTY MUCH WARRANTS GOING W/A DRY FCST OVERNIGHT. OTRWS MOD
GRADIENT FLW TO CONT W/MILD NIGHT XPCD.

ON SUN WARM SECTOR WILL DEEPEN FURTHER AS SW IMPULSE OUT WEST
AMPLIFIES FURTHER THROUGH THE CNTRL ROCKIES. LL THERMAL RIDGE BLDS A
BIT FURTHER DURING THE AFTN AS SFC CYCLONE MIGRATES INTO ERN IA. XPC
MUCH OF THE DAY WILL REMAIN DRY FOR MOST AS CONVN IF FOCUSED INVOF
OF SFC FNTL ZONE. ALTHOUGH LOW CHC MENTION STILL WARRANTED FAR NW
SUN AFTN TIED TO LLJ DVLPMNT AND BTR THETA-E RIDGING/MSTR FLUX LATE.
WARM START AND BINOVC AGAIN FVRS WARMEST MOS TEMPS W/AN 80 DEGREE
READING PSBL OVR NW OH.

&&

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 454 PM EDT SAT APR 12 2014

SOME OF THE MAIN CHALLENGES THIS PERIOD INCLUDE THE POTENTIAL FOR
HEAVY RAIN SUNDAY NIGHT INTO MONDAY FOLLOWED BY THE POSSIBILITY FOR
SNOW MONDAY NIGHT. THE LATEST GFS...SRF AND ECMWF ALL SUPPORT THE
HEAVIEST PRECIPITATION REMAINING TO THE NORTH OF THE AREA INTO
SUNDAY EVENING...WITH INCREASING CHANCES FOR RAIN OVERNIGHT SUNDAY
NIGHT AS THE FRONT MOVES SOUTHEAST. ALTHOUGH LOW LEVEL WIND SPEEDS
WILL BECOME IMPRESSIVE AROUND 65 KNOTS SUNDAY NIGHT...A FAIRLY
UNIFORM DIRECTION WITH TALL BUT THIN CAPE SHOULD LIMIT THE CHANCES
FOR SEVERE STORMS. CURRENT THINKING IS TOTAL RAINFALL AMOUNTS SHOULD
RANGE FROM AROUND A HALF AN INCH TO AN INCH. MUCH COLDER AIR WILL
SPREAD INTO THE REGION LATER MONDAY...SETTING THE STAGE FOR THE
CHANCE OF A RAIN/SNOW MIX...AND THEN ALL SNOW BY LATE MONDAY NIGHT.
THE 12 KM NAM STILL SUPPORTS A TRAILING SHORTWAVE WITH SOME SNOW
ACCUMULATION BY LATE MONDAY NIGHT...SO HAVE A CHANCE FOR SNOW
NORTHWEST AREAS. OTHERWISE...VERY CHILLY AIR WILL SPREAD INTO THE
REGION MONDAY NIGHT...WITH HIGHS IN THE MID 30S TO LOWER 40S...SOME
20 DEGREES BELOW NORMAL TUESDAY. WENT WITH THE LOWER END ECMWF AND
GFS ENSEMBLES TEMPS. TEMPERATURES WILL RECOVER TO NEAR NORMAL BY
THURSDAY AHEAD OF AN UPSTREAM UPPER TROF.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1244 AM EDT SUN APR 13 2014

VFR CONDITIONS WILL LIKELY PERSIST THROUGH MOST OF THE TAF PERIOD
AS NORTHERN INDIANA REMAINS IN WARM SECTOR. PARTIAL DECOUPLING HAS
ALLOWED WINDS TO DIMINISH TO LESS THAN 10 KNOTS IN MANY LOCATIONS
AS OF 04Z...BUT SHOULD SEE SOUTHERLY WINDS INCREASE AGAIN LATER
THIS MORNING/AFTERNOON AS DEEP DIURNAL MIXING COMMENCES AND LOW
LEVEL FLOW INCREASES IN RESPONSE TO UPSTREAM HEIGHT FALLS. LOW
CHANCE REMAINS FOR SOME CONVECTION TO CLIP SBN LATER THIS
AFTERNOON/EVENING AS WEAK INSTABILITY BUILDS AND LOWER AMPLITUDE
(CONVECTIVELY ENHANCED) SHORTWAVE ENERGY POSSIBLY DETACHES
CONVECTION SOUTH INTO WARM SECTOR. MUCH BETTER CHANCES FOR
RAIN/RESTRICTIONS WILL CONTINUE TO RESIDE NORTH AND WEST OF THE
TAF SITES ALONG A WELL DEFINED FRONTAL BOUNDARY THAT WILL FINALLY
WORK INTO AREA LATER TONIGHT.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EDT EARLY THIS MORNING FOR
     LMZ046.

&&

$$

UPDATE...MARSILI
SYNOPSIS...BENTLEY
SHORT TERM...T
LONG TERM...SKIPPER
AVIATION...STEINWEDEL


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