Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 291850
AFDIND

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

.UPDATE...
THE LONG TERM SECTION HAS 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 NIGHT THROUGH SUNDAY/...
ISSUED AT 250 PM EDT SUN MAR 29 2015

FIRST HALF OF THE EXTENDED WILL BE ACTIVE AS A COLD FRONT SLOWLY
DROPS THROUGH THE REGION IN A QUASI-ZONAL FLOW PATTERN ALOFT. WARM
START WITH SOUTHERLY FLOW AHEAD OF THE FRONT WEDNESDAY NIGHT. OP GFS
APPEARS TO BE SHOWING ITS PROGRESSIVE BIAS WITH SYSTEMS SO TYPICALLY
SEEN AT BEYOND 4 DAYS OUT. HAVE LEANED CLOSER TO THE GLOBAL MODELS
AND ESPECIALLY THE ECMWF WHICH DELAY MOST OF THE CONVECTION
ASSOCIATED WITH THE FRONT UNTIL THURSDAY MORNING FOR MOST OF THE
FORECAST AREA.

THURSDAY EXPECTED TO BE THE MOST UNSETTLED DAY OF THE EXTENDED AS
THE FRONT MOVES SLOWLY THROUGH THE REGION. PRESENCE OF INSTABILITY
WARRANTS A MENTION OF THUNDERSTORMS THURSDAY AND THURSDAY NIGHT.
WILL HOLD ONTO PRECIP INTO FRIDAY AS WELL AS A SECONDARY WAVE
DEVELOPS ALONG THE FRONT OVER THE SOUTHERN PLAINS AND RIDES ALONG
THE BOUNDARY THROUGH THE GREAT LAKES.

THE FRONT WILL FINALLY SHIFT AWAY TO THE SOUTHEAST FRIDAY
NIGHT...SETTING THE STAGE FOR A PLEASANT BUT COOL WEEKEND AS HIGH
PRESSURE BUILDS ACROSS THE OHIO VALLEY. HIGHS AROUND 70 ON THURSDAY
WILL FALL BACK INTO THE 50S FOR MUCH OF THE REST OF THE PERIOD.

&&

.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...RYAN
AVIATION...RYAN

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