Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 311623
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1223 PM EDT TUE MAR 31 2015

.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 422 AM EDT TUE MAR 31 2015

HIGH PRESSURE WILL MOVE ACROSS THE GREAT LAKES AND OHIO VALLEY LATE
TODAY AND TONIGHT BEFORE MOVING TO THE EASTERN STATES ON WEDNESDAY.
THIS WILL RESULT IN ABOVE NORMAL TEMPERATURES WITH HIGHS IN THE 60S
TODAY AND WEDNESDAY AND 70S THURSDAY.

THEN...A FRONTAL SYSTEM WILL BRING WIDESPREAD SHOWERS AND SOME
THUNDERSTORMS TO THE AREA THURSDAY AND THURSDAY NIGHT. THE SHOWERS
WILL LINGER THROUGH FRIDAY NIGHT AS COOLER TEMPERATURES MOVE IN FOR
THE WEEKEND BEHIND THE SYSTEM. FINALLY...ANOTHER SYSTEM WILL BRING
SHOWERS BACK TO THE AREA BY MONDAY.

&&

.NEAR TERM /REST OF TODAY/...

ISSUED AT 926 AM EDT TUE MAR 31 2015

UPDATE...
FORECAST IS ON TRACK...SO NO CHANGES. CURRENT TEMPS ACROSS THE
AREA ARE GENERALLY IN THE 50S WITH WESTERLY WINDS OF 10 TO 15
MPH...GUSTING TO 30 MPH. UPDATED GRIDS HAVE BEEN SENT.

PREVIOUS DISCUSSION...
A DRY BACKDOOR COLD FRONT WILL DROP SOUTH ACROSS THE AREA TODAY.
WITH ONLY SHALLOW MOISTURE AROUND 925 MILLIBARS AND ABOVE 500
MILLIBARS...SHOULD SEE VERY LITTLE CLOUD COVER. WINDS WILL SHIFT TO
NORTHWEST BEHIND THE FRONT. BUFKIT SUGGESTS COULD SEE WIND GUSTS TO
NEAR 25 MPH MAINLY NORTH AND EAST.

WITH COLD ADVECTION AS REFLECTED IN MODEL 850 MILLIBAR TEMPERATURES
SLIDING FROM 8 TO 10 DEGREES CELSIUS THIS MORNING TO 3 TO 5 DEGREES
THIS EVENING...FAVOR TEMPERATURES AT OR BELOW 00Z OPERATIONAL MOS
AND CLOSER TO ENSEMBLE MEAN MOS GUIDANCE TODAY. THIS SHOULD
TRANSLATE TO AFTERNOON HIGHS IN THE UPPER 50S NORTHEAST TO THE UPPER
60S SOUTHWEST.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
ISSUED AT 422 AM EDT TUE MAR 31 2015

MAIN CHALLENGE FOR THE SHORT TERM WILL BE TIMING AND COVERAGE OF
SHOWER AND THUNDERSTORM ACTIVITY ALONG WITH TEMPERATURES.

MODELS IN GOOD AGREEMENT THAT SURFACE HIGH PRESSURE WILL SETTLE EAST
ACROSS THE GREAT LAKES AND OHIO VALLEY TONIGHT AND WEDNESDAY...WHILE
AN UPPER RIDGE WILL TRAIL ACROSS THE AREA WEDNESDAY AND WEDNESDAY
EVENING. IN ADDITION...MODEL RH TIME SECTIONS WERE SHOWING A DRY
COLUMN. THIS SHOULD RESULT IN DRY WEATHER WITH VERY LITTLE CLOUD
COVER THROUGH AT LEAST WEDNESDAY EVENING. MEANWHILE...RETURN FLOW
WILL RESULT IN WARM AIR ADVECTION STARTING LATE WEDNESDAY WITH 850
MILLIBAR TEMPERATURES RISING TO ABOVE 10 DEGREES CELSIUS BY 06Z
THURSDAY. THIS SHOULD ALLOW TEMPERATURES TO REACH 00Z TUESDAY MOS
NUMBERS OR BETTER ON WEDNESDAY WITH AFTERNOON HIGHS IN THE MID 60S
NORTHEAST TO THE LOWER 70S SOUTHWEST. PREFER TEMPERATURES BELOW 00Z
MOS FOR TONIGHT WITH CLEAR SKIES AND LIGHT WINDS.

MODELS CONTINUE TO HAVE SOME TIMING DIFFERENCES WITH A COLD FRONT
AND VARIOUS IMPULSES THAT WILL BE RIDING NORTHEAST ALONG IT AS IT
SETTLES SOUTHEAST ACROSS CENTRAL INDIANA THURSDAY NIGHT. THE 00Z
ECMWF IS THE SLOWEST TO MOVE THE FRONT THROUGH AND PREFERRED WITH
THE WAVES OF LOW PRESSURE EXPECTED TO SLOW IT DOWN. THE 00Z ECMWF
MOVES THE COLD FRONT TO SOUTH CENTRAL INDIANA BY 12Z FRIDAY. PRIOR
TO THE COLD FRONT...A WARM FRONT WILL MOVE THROUGH THE AREA
WEDNESDAY EVENING WITH RETURN FLOW INCREASING OVERNIGHT WEDNESDAY
NIGHT ACROSS WESTERN PARTS OF CENTRAL INDIANA AND THURSDAY ACROSS
THE ENTIRE AREA. THIS SHOULD RESULT IN A FEW THUNDERSTORMS JUST
PRIOR TO 12Z THURSDAY ACROSS WEST CENTRAL INDIANA. MODELS HAVE A
40-50 KNOT LOW LEVEL JET ACROSS NORTHWEST PARTS OF CENTRAL INDIANA
AT 12Z THURSDAY AND ACROSS THE REST OF THE AREA BY 18Z. WITH THE JET
BRINGING IN WARM...MOIST AND UNSTABLE AIR AHEAD OF THE COLD
FRONT...AND UPPER WAVE APPROACHING FROM THE SOUTHWEST...SHOULD SEE
WIDESPREAD
THUNDERSTORMS THURSDAY. SPC DAY3 SEVERE OUTLOOK WAS BRINGING A
MARGINAL RISK OF SEVERE WEATHER TO ALL OF CENTRAL INDIANA. WITH 25
KNOT SHEAR FROM 1000-700 MILLIBARS...VEERING WITH HEIGHT...CURVED
HODOGRAPH AND MIXED LAYER CAPE TO AROUND 500 J/KG...WOULD NOT BE
SURPRISED TO SEE THAT UPGRADED IN LATER OUTLOOKS.

THUNDERSTORM COVERAGE SHOULD INCREASE THURSDAY NIGHT...ESPECIALLY
SOUTH...AS THE PREVIOUS MENTIONED WAVES SLIDE ALONG THE COLD FRONT.
THUS...BUMPED POPS UP TO CATEGORICAL.

WENT AT OR BELOW 00Z MOS DAYTIME HIGHS AND ABOVE NIGHTTIME LOWS DUE
TO THE EXPECTED HIGH COVERAGE OF CLOUD COVER. STILL...TEMPERATURES
SHOULD REACH THE UPPER 60S AND LOWER 70S THURSDAY.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
ISSUED AT 337 AM EDT TUE MAR 31 2015

TWO ACTIVE PERIODS EXPECTED DURING THE LONG TERM TIME FRAME...EARLY
AS A FRONTAL BOUNDARY LINGERS TO OUR SOUTH AND LATER IN THE PERIOD
AS BROAD LOW PRESSURE DEVELOPS OVER THE PLAINS AND DRAWS AMPLE
MOISTURE INTO THE OHIO VALLEY FOR SHOWERS AND PERHAPS THUNDERSTORMS.
INITIALIZED BLEND HANDLED THINGS WELL AND FEW CHANGES WERE REQUIRED.

WITH UPPER LEVEL FLOW QUASIZONAL OR OCCASIONALLY WEAKLY CYCLONIC
DURING THE PERIOD...EXPECT TEMPERATURES TO BE AT OR SLIGHTLY BELOW
NORMAL...WHICH IS ROUGHLY WHERE CONSENSUS NUMBERS PUT IT. ACCEPTED
BLEND.

&&

.AVIATION /DISCUSSION FOR 311800Z TAF ISSUANCE/...
ISSUED AT 1223 PM EDT TUE MAR 31 2015

VFR CONDITIONS EXPECTED THROUGHOUT THE FORECAST PERIOD.

HIGH PRESSURE WILL MAINTAIN DRY WEATHER AND MAINLY CLEAR SKIES
ACROSS CENTRAL INDIANA THROUGH WEDNESDAY MORNING. MVFR STRATOCU
DROPPING SOUTH FROM THE GREAT LAKES MAY BRIEFLY GRAZE KLAF THIS
AFTERNOON...BUT MOST OF THESE CLOUDS ARE EXPECTED TO MIX OUT OVER
THE NEXT FEW HOURS. NORTHWEST WINDS WILL CONTINUE TO GUST TO
20-25KTS THROUGH THE AFTERNOON BUT AS LOW PRESSURE OVER OHIO MOVES
AWAY TO THE EAST...WIND WILL BECOME LIGHT AND VARIABLE THIS
EVENING. LIGHT SOUTHERLY FLOW WILL DEVELOP WEDNESDAY MORNING AS
THE HIGH DRIFTS OFF TO THE EAST.

&&

.IND WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SYNOPSIS...MK
NEAR TERM...MK/TDUD
SHORT TERM...MK
LONG TERM...NIELD
AVIATION...RYAN

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