Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 271725
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
125 PM EDT SUN JUL 27 2014

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

&&

.SYNOPSIS...
ISSUED AT 412 AM EDT SUN JUL 27 2014

A COLD FRONT WILL DROP SOUTHEAST ACROSS CENTRAL INDIANA TODAY AS AN
UPPER WAVE PIVOTS SOUTHEAST FROM THE UPPER MIDWEST TO THE GREAT
LAKES. THESE FEATURES WILL INTERACT WITH A MOIST AND UNSTABLE
AIRMASS AND RESULT IN SCATTERED THUNDERSTORMS...SOME OF WHICH COULD
BE STRONG TO SEVERE...ESPECIALLY ACROSS SOUTHEASTERN PARTS OF
CENTRAL INDIANA. DRIER AND MUCH COOLER AIR WILL FILTER IN BEHIND THE
FRONT WITH AFTERNOON HIGHS ONLY IN THE 70S EARLY TO MID WEEK. SMALL
THUNDERSTORM CHANCES WILL RETURN BY WEDNESDAY AS CYCLONIC FLOW
CONTINUES.

&&

.NEAR TERM /TODAY/...
ISSUED AT 412 AM EDT SUN JUL 27 2014

STRONG TO SEVERE THUNDERSTORMS WILL BE THE MAIN FOCUS TODAY AS AN
UPPER WAVE PIVOTS SOUTHEAST FROM NEBRASKA TO WISCONSIN AND
EVENTUALLY MICHIGAN. THIS WAVE WILL FORCE A COLD FRONT SOUTHEAST
ACROSS CENTRAL INDIANA THIS AFTERNOON. THIS FRONT WILL INTERACT WITH
AN UNSTABLE AIRMASS /AFTERNOON MIXED LAYER CAPES 1500 TO 2500 J/KG/
AND 50 TO 60 KNOT DEEP SHEAR TO TRIGGER SCATTERED THUNDERSTORMS
TODAY. THE BEST CHANCE OF SEVERE STORMS LOOKS TO BE ACROSS OUR
SOUTHEASTERN HALF IN LEFT EXIT REGION OF 65 KNOT MID LEVEL JET
STREAK AND NEAR 850 MILLIBAR 30 KNOT MAX. STILL...THE WHOLE FORECAST
AREA IS IN THE DAY1 SPC SLIGHT RISK WHICH LOOKS REASONABLE. WITH
DEEP MOSTLY UNI-DIRECTIONAL SHEAR...DAMAGING WINDS LOOKS TO BE A
BIGGER THREAT THAN TORNADOES...HOWEVER WOULD NOT RULE OUT AN
ISOLATED ONE OR TWO ESPECIALLY ACROSS OUR SOUTHEASTERN COUNTIES.

CURRENTLY...STRONG STORMS WERE MARCHING SOUTHEAST ACROSS EAST
CENTRAL ILLINOIS IN THE NORTHWEST FLOW ALOFT. AFTERNOON SEVERE
POTENTIAL WILL HINGE ON HOW WIDESPREAD THE MORNING CONVECTION IS.
WIDESPREAD MORNING STORMS WOULD LIKELY KEEP MODEL INSTABILITY
NUMBERS FROM BEING REALIZED AND LIMIT THE SEVERE POTENTIAL DESPITE
THE STRONG SYNOPTIC FORCING.

WITH DRIER AIR WORKING IN ALOFT AND STORM MOTION OF 30 KNOTS OR
MORE...FLASH FLOODING DOES NOT LOOK LIKE A HUGE CONCERN.

00Z MOS VERY CLOSE ON TEMPERATURES TODAY...LOOKS REASONABLE AND
MATCHES WITH REGIONAL BLEND.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 412 AM EDT SUN JUL 27 2014

THE MAIN FOCUS FOR THE SHORT TERM WILL BE TEMPERATURES AS DRY AND
MUCH COOLER AIR INVADES THE AREA IN THE WAKE OF A COLD FRONT.

MODELS IN GOOD AGREEMENT THAT AN UPPER TROUGH WILL PIVOT EAST ACROSS
THE EASTERN GREAT LAKES TONIGHT SWEEPING A STRONG COLD FRONT WELL
EAST OF THE AREA. WOULD NOT RULE OUT AN EVENING
THUNDERSTORM...ESPECIALLY SOUTHEAST CLOSER TO THE BETTER INSTABILITY
AND DEPARTING COLD FRONT...HOWEVER...BETTER BET IS ANY ACTIVITY WILL
BE EAST OF THE AREA BY 00Z TONIGHT WITH JUST SOME LEFT OVER STRATUS
POSSIBLE WITH MODEL SOUNDINGS SHOWING LINGERING LOW LEVEL MOISTURE.
THE REMAINDER OF THE SHORT TERM...CYCLONIC FLOW AROUND THE BASE OF
STRONG HUDSON BAY VORTEX EXPECTED TO GENERATE A DECENT AMOUNT OF
DIURNAL CU. WOULD NOT COMPLETELY RULE OUT AN INSTABILITY SHOWER OR
TWO...BUT CHANCES TOO LOW TO MENTION.

MODEL 850 MILLIBAR TEMPERATURES FROM 9 TO 11 DEGREES CELSIUS
SUGGESTS LEANING TOWARDS THE COOLER 00Z NAM MOS WITH WELL BELOW
NORMAL HIGHS IN THE LOWER TO MID 70S. NORMAL HIGHS FOR THIS TIME OF
YEAR ARE IN THE MID 80S. MEANWHILE...SIMILAR MOS LOWS IN THE LOWER
60S LOOK GOOD TONIGHT WITH LOWS IN THE 50S THEREAFTER. WOULD NOT
EVEN RULE OUT UPPER 40S IN SOME LOCALIZED AREAS MONDAY NIGHT.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY NIGHT/...

ISSUED AT 340 AM EDT SUN JUL 27 2014

A VERY BROAD UPPER LOW CENTERED OVER THE HUDSON BAY WILL EXTEND INTO
THE EASTERN U.S.  THIS SYSTEM WILL BE RESPONSIBLE FOR PERIODS OF
SHOWERS AND THUNDERSTORMS THROUGHOUT THE PERIOD AS SEVERAL SHORT
WAVES RIDE ALONG THAT UPPER LOW. LATEST INITIALIZATION IS
HIGHLIGHTING BEST PRECIP CHANCES DURING THE AFTERNOON HOURS
THROUGHOUT THE EXTENDED PERIOD IN ASSOCIATION WITH PEAK HEATING OF
THE DAY.  MODELS CLOSE OFF AN UPPER LOW OVER THE OHIO VALLEY ON
SATURDAY AND INCREASE PRECIP CHANCES AS A RESULT.  TEMPS THROUGH THE
PERIOD WILL BE BELOW NORMAL WITH HIGHS IN THE UPPER 70S/LOW 80S AND
LOWS IN THE UPPER 50S/LOW 60S.

&&

.AVIATION /DISCUSSION FOR 271800Z TAF ISSUANCE/...
ISSUED AT 125 PM EDT SUN JUL 27 2014

MVFR/IFR CEILINGS EARLY THIS AFTERNOON WILL IMPROVE TO VFR LATE
THIS AFTERNOON AND EVENING. MVFR AND LOWER CONDITIONS RETURN LATE
TONIGHT INTO MONDAY MORNING.

WEAK BOUNDARY NEARING KIND AND KBMG CURRENTLY AND SHOULD BE EAST
OF ALL TERMINALS NEAR OR SHORTLY AFTER 18Z. WINDS WILL VEER TO
W/NW ONCE THE BOUNDARY PASSES. ADDITIONALLY...LOW CEILINGS AT
800-1500FT WILL DEPART TO THE EAST OF THE TERMINALS WITH THE
PASSAGE OF THE BOUNDARY...GRADUALLY IMPROVING TO VFR CU BY 19-20Z
AT ALL SITES. SECONDARY BOUNDARY NOTED NICELY ON VIS SATELLITE...
EXTENDING FROM NEAR KORD TO KBMI AND KSPI AT 17Z. THIS BOUNDARY
MAY SERVE AS THE FINAL CATALYST FOR SCATTERED LINEAR CONVECTIVE
DEVELOPMENT LATER THIS AFTERNOON...ESPECIALLY AT KIND AND KLAF.
WILL CONTINUE TO HIGHLIGHT A 3-4 HOUR WINDOW FOR VCTS AT ALL SITES
AND FINE TUNE AS CONVECTION ORGANIZES OVER THE NEXT FEW HOURS.
WINDS WILL ALSO INCREASE AS DRIER AIR SURGES INTO THE REGION...
WITH GUSTS AT 25 TO 30KTS EXPECTED DURING THE LATE AFTERNOON AND
EARLY EVENING. HIGHER GUSTS WILL BE POSSIBLE WITHIN CONVECTION.

MUCH DRIER AIR BUILDS WITH A PERIOD OF MAINLY CLEAR SKIES THIS
EVENING. AS COLD POOL ALOFT EXPANDS SOUTH OVERNIGHT...EXPECT MVFR
STRATUS TO EXPAND ACROSS THE TERMINALS. MAY SEE VISIBILITY
RESTRICTIONS AS WELL...ESPECIALLY AT KBMG WHERE HEAVY RAIN FELL
EARLIER TODAY. LOWER CEILINGS WILL LINGER THROUGH MUCH OF THE
MORNING WITH SOME IMPROVEMENTS NEAR THE END OF THE FORECAST
PERIOD. COULD SEE A FEW SHOWERS IMPACT KIND...BUT COVERAGE NOT
EXPECTED TO BE HIGH ENOUGH TO WARRANT A MENTION. N/NW WINDS WILL
INCREASE AGAIN TO 10-15KTS BY MIDDAY MONDAY...POSSIBLY WITH HIGHER
GUSTS.

&&

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

&&

$$

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

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