Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 291838
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
238 PM EDT SUN MAR 29 2015

.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 236 PM EDT SUN MAR 29 2015

A FRONTAL SYSTEM IS EXPECTED TO PASS ACROSS THE AREA TONIGHT. IN THE
WAKE OF THIS FRONT...HIGH PRESSURE WILL MOVE IN FOR THE EARLY PARTS
OF THE WEEK. ANOTHER FRONTAL SYSTEM MAY AFFECT THE AREA AROUND
THURSDAY OR FRIDAY.

&&

.NEAR TERM /REST OF THIS AFTERNOON AND TONIGHT/...
ISSUED AT 236 PM EDT SUN MAR 29 2015

RADAR LOOP INDICATES A BAND OF PRECIPITATION CURRENTLY MOVING
THROUGH THE WESTERN ZONES. MOST OF THIS APPEARS TO BE
RAIN...ALTHOUGH DUAL POL SUGGESTS THERE MIGHT BE A LITTLE SLEET
ALONG THE LEADING EDGE. EXTRAPOLATION AND SHORT TERM MODEL GUIDANCE
SUGGESTS THIS AREA OF RAIN WILL BE OVER THE SOUTHEAST ZONES AROUND
SUNSET...EXITING THE AREA SHORTLY AFTER. COLD FRONT LAGS BEHIND THE
BETTER LIFT BY ABOUT 6 HOURS...SO WILL KEEP SOME CHANCE POPS GOING
UNTIL ABOUT 300500Z.

MAY BE AM PERIOD OF LOWER LEVEL CLOUD IN THE POST FRONTAL ZONE LATE
TONIGHT...BUT APPEARS SKIES SHOULD CLEAR OUT TOWARDS DAYBREAK
MONDAY.

LOW LEVEL THICKNESSES SUGGEST TONIGHT/S LOWS MAY BE ABOUT A CATEGORY
COOLER THAN THE GFS MOS GUIDANCE. WILL CUT THE GUIDANCE LOWS ABOUT
2-4 DEGREES.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 236 PM EDT SUN MAR 29 2015

NORTHWEST UPPER FLOW WILL GRADUALLY BECOME MORE ZONAL BY THE MIDDLE
OF THE WEEK AS MEAN UPPER TROUGH OVER THE EASTERN PARTS OF THE
COUNTRY LIFTS OFF TO THE NORTHEAST.

MODEL DATA SUGGEST A SHORT WAVE TROUGH MAY PUSH ACROSS THE GREAT
LAKES REGION AROUND MONDAY NIGHT AND TUESDAY. AT THIS
POINT...APPEARS MOST OF THE LIFT/ASSOCIATED PRECIPITATION THREAT
WILL BE TO THE NORTHEAST OF THE FORECAST AREA...BUT IT MAY CLOSE
OVER THE NORTHEAST ZONES. WILL KEEP THINGS DRY FOR NOW AND MONITOR
TRENDS.

ONLY OTHER CONCERN FOR PRECIPITATION DURING THIS PERIOD IS ON
WEDNESDAY AS WARM ADVECTION DEVELOPS AHEAD OF NEXT FRONTAL SYSTEM
THAT IS EXPECTED TO BE MOVING EAST THROUGH THE PLAINS BY THAT TIME.
OPERATIONAL AND ENSEMBLE DATA SUGGEST PRECIPITATION THREAT WITH THIS
NEXT SYSTEM WILL HOLD OFF UNTIL AFTER THIS PERIOD.

PROGGED LOW LEVEL THICKNESSES SUGGEST THE GFS MOS TEMPERATURE
GUIDANCE MAY BE ON THE WARM SIDE...ESPECIALLY BY TUESDAY AND TUESDAY
NIGHT. WILL DROP THE GUIDANCE TEMPERATURES ABOUT A CATEGORY AT THOSE
TIMES.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
ISSUED AT 225 AM EDT SUN MAR 29 2015

MILD AND ACTIVE EXTENDED WILL BE IN STORE ACROSS THE THE GREAT
LAKES...OHIO VALLEY AND THE SOUTH FOR THE FIRST WEEK OF APRIL.
MODELS AGREE THAT THE UPPER FLOW WILL BE FAST AND QUASI-ZONAL. THAT
IN IT ITSELF LENDS ITSELF TO TIMING DIFFICULTIES FOR THE MODELS WITH
THE VARIOUS EMBEDDED DISTURBANCES. THE BIGGEST MODEL DIFFERENCES
RELATE TO A LATE WEEKEND SURFACE WAVE AND ITS STRENGTH. AS FAR AS
OPERATIONAL MODELS GO...THE 12Z ECMWF WAS THE STRONGEST WITH THIS
FEATURE...WHILE THE 00Z GFS WAS THE WEAKEST AND FURTHEST SOUTH. THE
00Z CANADIAN WAS MORE OF A COMPROMISE. MEANWHILE...THE ENSEMBLE
MEANS LEANED TOWARDS THEIR DETERMINISTIC SOLUTIONS. THE MAJORITY OF
THE ENSEMBLE MEMBERS FAVORED A MORE NORTHERLY TRACK OF A SURFACE LOW
ALBEIT NOT AS STRONG AS THE ECMWF. FINALLY...THE ECMWF AND ITS
ENSEMBLE HAVE BEEN MORE CONSISTENT. SO...PREFER A SOLUTION CLOSER TO
THE EURO ENSEMBLE MEAN...BUT WITH DIFFERENCES STILL YET TO BE
RESOLVED...WILL NOT MAKE LARGE CHANGES TO THE REGIONAL BLEND.

THE WEATHER PREDICTION CENTER SURFACE PROGS FROM LATE LAST EVENING
SUGGEST A WARM FRONT WILL LIFT NORTHEAST ACROSS CENTRAL INDIANA
WEDNESDAY AFTERNOON AND EVENING. THEN...AN ASSOCIATED COLD FRONT IS
EXPECTED TO DROP SOUTHEAST ACROSS NORTHERN PARTS OF CENTRAL INDIANA
THURSDAY NIGHT BUT STALL SOMEWHERE NEARBY ON FRIDAY AS A SURFACE
WAVE SLIDES NORTHEAST ALONG THE FRONT. THE FRONT SHOULD THEN DROP
SOUTHEAST TO THE SOUTHERN STATES FRIDAY NIGHT AS THE WAVE EXITS
NORTHEAST. MOIST SOUTHERLY FLOW AHEAD OF THIS SYSTEM WILL ALLOW
TEMPERATURES TO RISE ABOVE NORMAL IN THE 60S BY THURSDAY. IT WILL
ALSO SERVE AS AN INGREDIENT FOR PERIODS OF SHOWERS WEDNESDAY NIGHT
THROUGH FRIDAY. THUNDERSTORMS ALSO A GOOD BET PER ECMWF INSTABILITY
PROGS. DRY AND COOLER WEATHER WILL THEN TAKE OVER FOR THE LATTER
PART OF THE WEEKEND.

&&

.AVIATION /DISCUSSION FOR 291800Z TAF ISSUANCE/...
ISSUED AT 100 PM EDT SUN MAR 29 2015

MVFR CEILINGS POSSIBLE THIS EVENING INTO THE OVERNIGHT...OTHERWISE
VFR CONDITIONS EXPECTED.

MID LEVEL CLOUD DECK OVERSPREADING WESTERN INDIANA EARLY THIS
AFTERNOON AS A PREFRONTAL TROUGH APPROACHES FROM THE WEST. SHOWERS
ASSOCIATED WITH THIS FEATURE ARE ALREADY APPROACHING THE ILLINOIS-
INDIANA BORDER. WITH THE EXCEPTION OF POSSIBLY A BRIEF SHOWER AT
KLAF THIS AFTERNOON HOWEVER...EXPECT THIS INITIAL BATCH OF PRECIP
TO GRADUALLY WEAKEN AS IT MOVES INTO A VERY DRY AIRMASS. HI-RES
GUIDANCE SUGGESTING ADDITIONAL DEVELOPMENT ALONG THE PREFRONTAL
TROUGH BY LATE AFTERNOON...SPREADING ACROSS THE TERMINALS INTO THE
EARLY EVENING PRODUCING RAIN WITH NO RESTRICTIONS. BIGGER ISSUE
FOR THE AFTERNOON WILL BE THE WINDS WHICH WILL GUST UP TO 30KTS IF
NOT SLIGHTLY HIGHER OVER THE NEXT SEVERAL HOURS FROM THE SOUTH...
THEN THE SOUTHWEST THIS EVENING ONCE THE PREFRONTAL TROUGH PASSES.

THE PASSAGE OF A COLD FRONT LATER THIS EVENING WILL PRODUCE A
BRIEF PERIOD WITH SCATTERED SHOWERS AND CEILINGS DIPPING INTO THE
MVFR CATEGORY AS COLD ADVECTION GRAZES THE FORECAST AREA. WINDS
WILL REMAIN GUSTY THROUGH THE EVENING BUT SHOULD DROP OFF AROUND
OR SHORTLY AFTER MIDNIGHT. SKIES WILL CLEAR TOWARDS DAYBREAK AS
HIGH PRESSURE BUILDS IN FOR MONDAY. WEST-NORTHWEST WINDS UP TO
10KTS ARE EXPECTED INTO MONDAY AFTERNOON.

&&

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

$$

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

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