Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 242341
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
741 PM EDT THU APR 24 2014

.SYNOPSIS...
ISSUED AT 330 PM EDT THU APR 24 2014

A LOW PRESSURE SYSTEM WILL MOVE FROM MISSOURI INTO CENTRAL
INDIANA OVERNIGHT AND BRING SHOWERS TO THE REGION THROUGH FRIDAY
MORNING. LOWS TONIGHT WILL BE IN THE MID 40S TO LOWER 50S. HIGHS
ON FRIDAY WILL REACH INTO THE 60S WITH INCREASING SUNSHINE IN THE
AFTERNOON HOURS.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 352 PM EDT THU APR 24 2014

PRIMARY FOCUS ON APPROACH OF VIGOROUS UPSTREAM SHORTWAVE TROF
EMBEDDED WITHIN OVERALL NEGATIVE TILTED LONGWAVE PATTERN.
ATTENDANT WESTERN MO SURFACE LOW TO TRACK ENEWD INTO CNTRL IN BY
12 UTC FRI AND INTO NRN OH AT 18 UTC. STRONG MOISTURE FLUX
CONVERGENCE GIVEN ADVECTION OF 5 PLUS G/KG 8-5H LYR AS MID
TROPOSPHERIC FLOW OF 40-50KTS ACRS SRN MO MOVES UP OHIO RIVER
VALLEY BASIN. HAVE RELEGATED SLIGHT TSRA MENTION TO FAR SRN/SERN
CWA MAXIMIZED HODO WITH DEEP LAYER FORCED PARCEL ASCENT AMPLIFIED
BY ARRIVAL OF 80-100M/12HR ALONG WITH NORTHERN EXTENT OF MUCAPE
PLUME/APEX AOB 200 J/KG TOWARD DAYBREAK. SOME SLIGHT SLOWING OF
FRONTAL SYSTEM AFFORDED GIVEN NEG TILT/MATURATION TO OCCLUSION.
MAINTAIN WARM TEMPS ON FRI AS POST FNTL THERMAL TROF RATHER
NARROW... LACK OF STRONG UPSTREAM SFC RIDGE AND POTENTIAL STRONG
AFTERNOON INSOLATION.

&&

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 352 PM EDT THU APR 24 2014

FRONTAL BOUNDARY SHOULD BE CLEAR OF THE AREA AT THE START OF THE
PERIOD WITH A DRY START TO FRI EVENING. A HANDFUL OF MODELS STILL
BRING A WEAK DISTURBANCE ACROSS THE CWA WITH LIGHT QPF. NOT OVERLY
IMPRESSED BUT GIVEN LOCATION OF FRONT JUST SOUTH OF THE AREA CAN`T
DISCOUNT ENTIRELY. HAVE WENT WITH SLGT CHC POPS ONLY LATE FRI NGT.

OTHERWISE FOCUS WILL SHIFT TO LARGE UPPER LOW THAT WILL SLOWLY MAKE
ITS PRESENCE KNOWN ACROSS THE REGION TOWARDS MID WEEK. A MASSIVE
STRUGGLE SHOULD TAKE PLACE IN MSTR RETURN WITH LIMITED FLOW FROM THE
GULF UNTIL THE LOW DRAWS CLOSER. ECMWF CLOSEST TO THIS THOUGHT
PROCESS WITH OTHER MED RANGE MODELS TRYING TO BRING PRECIP IN
FASTER. AS A RESULT HAVE INCREASED POPS FAR SW STARTING SUN NGT AND
SLOWLY EXPANDING NE THROUGH MONDAY NIGHT AND TUESDAY WHEN UPPER LOW
BEGINS TO MOVE OVERHEAD. FROM THIS POINT FORWARDS IS WHERE IT
BECOMES SOMEWHAT MORE INTERESTING. AS NOTED ABOVE...MSTR FROM THE
GULF WILL BEGIN TO COME NORTH AND GET WRAPPED ON THE EAST SIDE OF
THE LOW. HINTS OF DEWPTS INTO THE 50S EXIST WITH GUIDANCE NUMBERS
POINTING TOWARD POTENTIAL HIGHS IN THE 60S TO MAYBE NEAR 70. TO
COMPLICATE FURTHER...AS IS TYPICAL WITH THESE SPRING CUT OFF
LOWS...POOL OF COLD 500 MB TEMPS WILL BE APPROACHING...POSSIBLY
PUSHING -20 C DEPENDING ON MODEL OF CHOICE. IF POCKET OF LIMITED
CLEARING CAN OCCUR...VERY STEEP LAPSE RATES WOULD ENSURE WITH
POTENTIAL FOR LOW TOPPED CONVECTION. SINCE THIS IS SEVERAL DAYS OFF
AND NO REAL AGREEMENT IN MODELS WILL KEEP TEMPS CONSERVATIVE FOR
HIGHS AND HOLD OFF ON ANY THUNDER MENTION. LOW WILL TAKE ITS OWN
SWEET TIME LEAVING THE AREA STILL GIVING LINGERING EFFECTS OUTSIDE
THE CURRENT PERIOD.

&&

.AVIATION/UPDATE...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 738 PM EDT THU APR 24 2014

POTENT SW TROUGH OVR ERN KS WILL SHEAR NEWD ACRS THE OH VALLEY
THROUGH FRI AFTN AS ATTENDANT SFC CYCLONE OCCLUDES OVR CNTRL IN FRI
AM EFFECTIVELY HOLDING BEST OF NARROW THETA-E PLUME WELL SOUTH OF
CWA LT TONIGHT. HWVR VIGOROUS LWR-MID MS VALLEY CONVN ONGOING THIS
EVENING SIGNALS POTENTIAL FCST BUST IN LIGHT OF CONCURRENT/MULTI RUC/HRRR
CYCLES WHICH INDICATE RAPIDLY DWINDLING WINDOW OF SATURATED ASCENT
LT TONIGHT AS SRN CONVN BOTTLES UP MORE APPRECIABLE LL MSTR PLUME.
THUS WILL MAKE BOLD ADJUSTMENTS TO POPS OVERNIGHT/FRI AM.

BRIEF AND NARROW WINDOW OF TOP-DOWN SATURATION AND INHERENT MVFR
CIGS XPCD TWD SUNRISE IN ASSOCN/W NEWD SHEARING SW TROUGH COMING OUT
OF ERN KS AND PASSAGE OF ATTENDANT SFC BNDRY. HWVR VFR CONDS XPCD
FOR THE REMAINDER OF THE PD. STG POST FNTL SUBSIDENCE AND DIURNALLY
ENHANCED MIXING XPCD ON FRI AFTN W/SFC GUSTS AOA 25KTS.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LMZ043-046.

&&

$$

SYNOPSIS...MURPHY
SHORT TERM...MURPHY
LONG TERM...FISHER
AVIATION...T


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