Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 311852
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
252 PM EDT FRI OCT 31 2014

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

&&

.SYNOPSIS...
ISSUED AT 252 PM EDT FRI OCT 31 2014

COLD CANADIAN AIR WILL INVADE CENTRAL INDIANA TONIGHT IN THE WAKE OF
A STRONG COLD FRONT BRINGING A KILLING FREEZE TO THE AREA. IN
ADDITION...AN UPPER LOW WILL MOVE INTO SOUTHEASTERN INDIANA THIS
EVENING AND RESULT IN SCATTERED SHOWERS WITH A CHANGE OVER TO SNOW
EXPECTED BY EARLY EVENING. A FEW LAKE EFFECT SNOW SHOWERS WILL
LINGER OVERNIGHT ACROSS NORTHWESTERN PARTS OF CENTRAL
INDIANA...OTHERWISE THE SNOW SHOWERS WILL BE ENDING. IN ADDITION TO
THE COLD...WINDY CONDITIONS WILL RESULT IN WIND CHILLS IN THE TEENS.

STRONG HIGH PRESSURE WILL BE BUILDING ACROSS THE AREA SATURDAY AND
SUNDAY RESULTING IN LITTLE CLOUD COVER BUT CONTINUED WELL BELOW
NORMAL TEMPERATURES. MONDAY WILL SEE TEMPERATURES RETURN TO CLOSE TO
NORMAL AS SOUTHWEST FLOW COMMENCES ON THE BACK SIDE OF THE HIGH. AS
MOISTURE INCREASES AND A COLD FRONT APPROACHES FROM THE WEST...THERE
WILL BE CHANCES OF SHOWERS EARLY TUESDAY THROUGH WEDNESDAY NIGHT.

&&

.NEAR TERM /TONIGHT/...

ISSUED AT 252 PM EDT FRI OCT 31 2014

MAIN CHALLENGE TONIGHT WILL BE ON PRECIPITATION TYPE...COVERAGE AND
TIMING AS WELL AS TEMPERATURES AND WIND CHILLS AS A DEEPENING UPPER
TROUGH CLOSES OFF OVER SOUTHEASTERN INDIANA AT 00Z SATURDAY BEFORE
QUICKLY MOVING TO THE MOUNTAINS OF EASTERN TENNESSEE BY 06Z SATURDAY.

REGARDING PRECIPITATION...THE RAIN SHOWERS SHOULD BE IN THE PROCESS
OF CHANGING OVER TO SNOW PER BUFKIT AS THE NEW FORECAST BEGINS. BY
00Z THIS EVENING...IT SHOULD ALL BE SNOW PER BUFKIT. SOUTHEASTERN
PARTS OF THE FORECAST SHOULD SEE THE MOST COVERAGE AS THE UPPER LOW
SETTLES ACROSS THAT AREA THIS EVENING. OUR NORTHWESTERN COUNTIES
COULD SEE SOME LAKE EFFECT SNOW SHOWERS AS WELL WITH DEEP NORTH
BOUNDARY LAYER FLOW TO 45 KNOTS. THE REST OF THE AREA SHOULD JUST
SEE ISOLATED TO SCATTERED SNOW SHOWERS ON THE BACK END OF THE
DEPARTING UPPER LOW. LAKE EFFECT SNOW COULD GO ON ALL TIL 06Z OR SO
UNTIL MODEL SOUNDINGS SHOW DRIER AIR AND SLIGHTLY LOWER WINDS.
OTHERWISE...THE THREAT FOR SNOW SHOULD BE OVER AROUND MIDNIGHT. DO
NOT SEE ANY THREAT FOR ACCUMULATION WITH ROAD TEMPERATURES STILL IN
THE MID TO UPPER 40S. SKIES SHOULD BE CLEARING OVERNIGHT AS WELL.

REGARDING TEMPERATURES AND WINDS...WINDS SHOULD STAY UP ALL NIGHT
BASED ON MESOSCALE MODEL SOUNDINGS WITH EVENING GUSTS TO 35 MPH AND
OVERNIGHT GUSTS TO 25 MPH. WITH SUCH STRONG COLD AIR
ADVECTION...PREFER COLDER 12Z GFS MOS...ALTHOUGH MAYBE NOT QUITE AS
COLD WITH WINDS STAYING UP. THIS BLEND WOULD RESULT IN A HARD FREEZE
WITH OVERNIGHT LOWS IN THE MID TO UPPER 20S. THERE IS EVEN A SMALL
CHANCE WE COULD BREAK THE NOVEMBER 1 RECORD LOW OF 24 DEGREES.
TRICK OR TREAT TEMPERATURES WILL BE DROPPING THROUGH THE 30S WITH
WIND CHILLS IN THE 20S AND POSSIBLY EVEN UPPER TEENS.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...

ISSUED AT 252 PM EDT FRI OCT 31 2014

MAIN FOCUS FOR THE SHORT TERM WILL BE TEMPERATURES.

MODELS AND ENSEMBLES AGREE THAT STRONG HIGH PRESSURE WILL BE
BUILDING ACROSS THE AREA SATURDAY THROUGH SUNDAY. MEANWHILE...MODEL
RH TIME SECTIONS WERE SHOWING THE COLUMN DRYING ON SATURDAY MORNING
WITH ONLY SOME INCREASE IN HIGH LEVEL MOISTURE ON SUNDAY AS CIRRUS
IS EXPECTED TO SPILL OVER TOP A SHARP MISSISSIPPI VALLEY UPPER RIDGE
ALOFT. SHOULD ALSO SEE INCREASE IN WARM ADVECTION MID CLOUDS SUNDAY
NIGHT AND MONDAY AS SOUTHWEST LOW LEVEL FLOW INCREASES AHEAD OF AN
APPROACHING FRONTAL SYSTEM.

MOS TEMPERATURES ARE CLOSE THROUGHOUT THE SHORT TERM WITH MODERATING
TRENDS LOOKING GOOD. SATURDAY WILL CONTINUE TO BE WELL BELOW NORMAL
WITH AFTERNOON HIGHS ONLY IN THE LOWER TO MID 40S.
MEANWHILE...ANOTHER HARD FREEZE IS IN STORE SATURDAY NIGHT. THIS
WILL ONLY BE SIGNIFICANT IN UNLIKELY EVENT THAT WE DO NOT SEE A HARD
FREEZE TONIGHT. THEN...SOUTHWEST FLOW WILL ALLOW TEMPERATURES TO
MODERATE AND BECOME NEAR NORMAL BY MONDAY WITH HIGHS IN THE MID 50S
TO AROUND 60 DEGREES ON TAP.

&&


.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ISSUED AT 227 PM EDT FRI OCT 31 2014

GIVEN RELATIVELY HIGH UNCERTAINTY...THE SUPERBLEND INITIALIZATION
WAS ACCEPTED FOR MOST ITEMS.

AN UPPER TROUGH WILL MOVE THROUGH THE AREA DURING THE LONG
TERM...BUT MODELS DIFFER ON HOW FAST IT EXITS THE AREA. ALSO...00Z
ECMWF AND 12Z DIFFER EXTENSIVELY ON HOW AN UPPER LOW IS HANDLED
ACROSS THE SOUTHWEST USA. THUS CONFIDENCE IS LOW IN LONG TERM.

A COLD FRONT WILL SLOWLY MOVE ACROSS THE REGION MONDAY NIGHT INTO
WEDNESDAY...AND THIS WILL KEEP CHANCES FOR RAIN IN THE FORECAST
DURING THAT TIME. HIGH PRESSURE SHOULD MOVE IN FOR THE END OF THE
WEEK SO WENT DRY THEN.

TEMPERATURES LOOK TO REMAIN NEAR AVERAGE TO ABOVE AVERAGE FOR MOST
OF THE PERIOD...BUT THEY WILL COOL DOWN BY FRIDAY.

&&

.AVIATION /DISCUSSION FOR THE 311800Z TAF ISSUANCE/...
ISSUED AT 1255 PM EDT FRI OCT 31 2014

MVFR CONDITIONS THROUGH FIRST HALF OF THE PERIOD...WITH VFR FOR
SECOND HALF. GUSTY WINDS THROUGHOUT...WITH STRONGEST GUSTS BEFORE
06Z.

SECONDARY SURFACE TROUGH WILL MOVE THROUGH THE SITES THIS AFTERNOON.
WIND GUSTS WILL INCREASE AS THIS PASSES WITH GUSTS OVER 30KT COMMON.
SCATTERED TO NUMEROUS SHOWERS WILL MOVE ACROSS THE AREA. AS
TEMPERATURES FALL...SOME SNOW SHOWERS COULD MIX IN AT ALL SITES.

HEAVIER SNOW SHOWERS FROM LAKE MICHIGAN MAY IMPACT KLAF AND REDUCE
VISIBILITY TO IFR BRIEFLY...BUT CONFIDENCE IS TOO LOW TO ADD TO THE
TAF AT THIS TIME.

AS SYSTEM MOVES EAST OVERNIGHT CONDITIONS WILL IMPROVE TO VFR. AM
GOING PESSIMISTIC IN KEEPING CLOUD COVER IN THROUGH THE NIGHT AS
MODELS MAY CLEAR THINGS OUT TOO FAST.

SATURDAY WILL SEE VFR CONDITIONS WITH WIND GUSTS NEAR 20KT AS HIGH
PRESSURE BUILDS IN.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
FREEZE WARNING FROM MIDNIGHT TONIGHT TO 10 AM EDT SATURDAY FOR
INZ021-028>031-035>049-051>057-060>065-067>072.

&&

$$

SYNOPSIS...MK
NEAR TERM...MK
SHORT TERM...MK
LONG TERM....50
AVIATION...50

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