Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 220201
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
901 PM EST FRI NOV 21 2014

.UPDATE...

AVIATION SECTION UPDATED.

&&

.SYNOPSIS...
ISSUED AT 332 PM EST FRI NOV 21 2014

HIGH PRESSURE WILL PUSH OFF TO THE EAST AS A WARM FRONT AND A STRONG
LOW PRESSURE SYSTEM ENTER FROM THE SOUTHWEST TONIGHT. THIS SYSTEM
WILL KEEP PRECIPITATION IN THE FORECAST THROUGH THE WEEKEND. IN ITS
WAKE...COLDER AND DRIER WEATHER WILL RETURN...THEN A UPPER LEVEL
SYSTEM WILL BRING CHANCES FOR SNOW TO THE AREA NEXT WEDNESDAY
THROUGH THURSDAY.

&&

.NEAR TERM /REST OF THIS AFTERNOON THROUGH TONIGHT/...
ISSUED AT 657 PM EST FRI NOV 21 2014

WITH REGIONAL RADAR TRENDS VERY SLOW TO SHOW ANY ECHOES AT
ALL AND DEWPOINTS REMAINING VERY DRY ACROSS THE AREA...HAVE PUSHED
BACK POPS AT LEAST A FEW HOURS WITH THIS UPDATE...AND MAY NEED TO
PUSH THEM BACK EVEN MORE DEPENDING ON HOW THINGS EVOLVE OVER THE
NEXT FEW HOURS. HRRR DOES HAVE SOME PRECIP IN THE FAR SOUTHWEST BY
04Z. IT IS A RACE BETWEEN WARM ADVECTION AND PRECIP ONSET AT THIS
POINT TO DETERMINE WHETHER ANY FREEZING PRECIP WILL FALL. PREVIOUS
DISCUSSION FOLLOWS.

ISSUED AT 332 PM EST FRI NOV 21 2014

FOR THE REST OF THIS AFTERNOON AND EARLY EVENING EXPECT INCREASING
CLOUD COVER FROM SOUTHWEST TO NORTHEAST AS A FRONTAL SYSTEM DRAPED
MOVES CLOSER TO THE FORECAST AREA. MODELS ARE TIMING THE MOISTURE
FROM THIS SYSTEM TO ARRIVE EVEN SLOWER THAN EXPECTED WHICH WILL
IMPACT PRECIP TYPE OVERNIGHT WHERE ONCE WIDESPREAD FREEZING RAIN WAS
EXPECTED. THIS PERIOD OF LIGHT FREEZING RAIN LOOKS LIKE A MUCH
SMALLER WINDOW FOR CENTRAL INDIANA AS WARM AIR ADVECTION REALLY
KICKS IN LATER THIS EVENING AND SURFACE TEMPERATURES BEGIN TO RISE
TO ABOVE FREEZING. THIS COMBINED WITH THE MUCH SLOWER ONSET OF
PRECIP. THE MAIN WINDOW FOR -FZRA RAIN IS 9PM THROUGH 5AM...QUICKLY
CHANGING OVER TO RAIN FROM SW TO NE AS THE WARMER AIR ARRIVES. QPF
AMOUNTS STILL LOOK EXTREMELY LOW...ONLY A FEW HUNDREDTHS OF AN INCH.

OPTED NOT TO ISSUE ANY STATEMENTS NOR HEADLINES FOR THE -FZRA RAIN
BASED ON THIS LATEST GUIDANCE AND WILL CONTINUE TO MONITOR
CONDITIONS UPSTREAM TO SEE IF A SPECIAL WEATHER STATEMENT IS NEEDED.
IN COORDINATION WITH SURROUNDING OFFICES WILL CONTINUE TO MENTION
THE LIGHT FREEZING RAIN AND POTENTIALLY SLICK/ICY ROADS FOR A BRIEF
PERIOD OVERNIGHT IN THE HWO AND WX STORY.

LOW TEMPS WILL OCCUR EARLY THIS EVENING (RANGING FROM MID 20S TO MID
30S) AND QUICKLY INCREASE TO MID 30S TO LOW 40S BY 12Z SAT!

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...
ISSUED AT 332 PM EST FRI NOV 21 2014

BY 10-12Z SATURDAY MORNING ALL THE POTENTIAL -FZRA WILL HAVE CHANGED
OVER TO RAIN. AND WARM AIR ADVECTION WILL CONTINUE TO FILTER INTO
THE AREA IN EARNEST THROUGH SATURDAY WITH HIGH TEMPERATURES COMING
IN EVEN WARMER THIS MODEL RUN WITH HIGHS RANGING FROM MID 40S
(NORTH) TO NEARLY THE MID 50S (FAR SOUTH COUNTIES) BY SAT 12Z

THE SURFACE LOW WILL CONTINUE ITS TRACK ACROSS THE MISSISSIPPI
VALLEY ON SATURDAY INTO SATURDAY NIGHT AND THERE CONTINUES TO LOOKS
LIKE A LULL DURING A GOOD PORTION OF THE DAY SATURDAY...SO BACK OFF
ON POPS OVER THE ENTIRE AREA. THE HIGHEST CHANCES FOR RAIN WILL BE
ON SUNDAY AS BEST LIFT FROM WARM FRONT AND LOW PRESSURE MOVES ACROSS
THE AREA. WILL CONTINUE WITH 100 PERCENT POPS...ESPECIALLY FOR THE
SECOND HALF OF SUNDAY.

IN TERMS OF TEMPS...AS MENTIONED ABOVE EXPECT HIGHS TO CLIMB INTO
THE 50S WITH DECENT WARM ADVECTION...AND LOWS TO BE IN THE 40S.

RAIN WILL SLOWLY BEGIN TO TAPER OFF ON MONDAY AS THE SYSTEM SLOWLY
MOST OFF TO THE EAST. COLD AIR WILL THEN MOVE BACK IN MONDAY
NIGHT IN THE WAKE OF THE FRONTAL PASSAGE. COULD SEE A FEW SNOW
SHOWERS IN THE NORTH AS WEAK WAVE MOVES THROUGH. FOR NOW INDICATED
A MIX OF -RA/SN LATE MONDAY AFTERNOON AND SLIGHT CHANCES FOR SNOW
SHOWERS OR FLURRIES ACROSS THE FAR NORTHERN TIER OF COUNTIES
MONDAY NIGHT.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ISSUED AT 255 PM EST FRI NOV 21 2014

COLD AIR WILL MOVE BACK IN MONDAY NIGHT IN THE WAKE OF THE FRONTAL
PASSAGE. COULD SEE A FEW SNOW SHOWERS IN THE NORTH AS WEAK WAVE
MOVES THROUGH. KEPT CHANCE FOR FLURRIES GOING TUESDAY IN THE
NORTHERN HALF OR SO AS WELL WITH CYCLONIC UPPER FLOW. WEDNESDAY ON
MODELS ARE SHOWING SOME DECENT DIFFERENCES IN THE UPPER PATTERN AND
ENSEMBLES ARE PRETTY VARIABLE SO WILL JUST GO WITH INITIALIZATION.
TEMPERATURES DO SEEM TO BE COMING TOGETHER A LITTLE COOLER FOR THAT
TIME SO STUCK WITH SMALL CHANCES FOR SNOW FOR PRECIP TYPE. THERE IS
SOME HINT OF A WARMUP OUT BEYOND FRIDAY BUT THAT REMAINS TO BE SEEN.

&&

.AVIATION /DISCUSSION FOR THE 220300Z IND TAF UPDATE/...

ONGOING TAF APPEARS IN GOOD SHARE AS WARM AIR ADVECTION IS ONGOING
AND CLOUDS OVER THE MID MISSISSIPPI RIVER VALLEY CONTINUE TO TRY
TO ADVECT EAST INTO THE VERY DRY AIR MASS IN PLACE ACROSS INDIANA.

LATEST HRRR SUGGESTS PRECIP ARRIVING IN THE AREA AROUND 08Z-09Z.
SURFACE TEMPS AT THAT TIME SHOULD BE IN THE MIDDLE 30S...WHICH
ONCE AGAIN SUPPORTS JUST RA AS PRECIP TYPE. WILL CONTINUE TO WATCH
CLOSELY.

PREVIOUS DISCUSSION BELOW

/DISCUSSION FOR THE 220000 TAFS/...
ISSUED AT 607 PM EST FRI NOV 21 2014

VFR EXPECTED THE NEXT 6-8 HOURS. A BRIEF PERIOD OF MVFR WILL BE
POSSIBLE FROM 07Z-12Z...BEFORE VFR CONDITIONS RETURN.

LIGHT FREEZING RAIN WILL BE POSSIBLE OVERNIGHT AT LAF.

CLOUDS OVER MISSOURI ASSOCIATED WITH STRONG WARM AIR ADVECTION AND
A STRONG LLJ WILL PUSH INTO THE INDIANA TAF SITES OVERNIGHT.
COLUMN ACROSS THE AREA IS QUITE DRY WITH DEW POINT TEMPS IN THE
SINGLE DIGITS TO LOW TEENS. THUS IT WILL TAKE SOME TIME FOR ANY
PRECIP TO MOIST UP THE COLUMN AS ANY PRECIP MAY START AS VIRGA.
FURTHERMORE...THE STRONG WARM AIR ADVECTION WILL ALLOW TEMPS TO
RISE THROUGH THE NIGHT...LIMITING THE WINDOW FOR ANY FREEZING
PRECIPITATION. DUE TO THIS HAVE FOR NOW HAVE LIMITED THE MENTION FOR
FREEZING RAIN TO THE LAF TAF SITE...WITH JUST RAIN EXPECTED
ELSEWHERE.

TIME HEIGHTS THEN CONTINUE TO SHOW PLENTIFUL LOWER LEVEL MOISTURE
THROUGH THE FORECAST PERIOD AMID WARM AIR ADVECTION WITHIN THE
COLUMN. THUS A RETURN TO VFR WILL BE EXPECTED AFT 12Z WITH SCT
SHOWERS IN THE AREA. A STRONG LLJ OF 50KT WORKING ACROSS THE AREA
MAY RESULT IN SOME LLWS WHICH HAS BEEN INCLUDED.

&&

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

&&

$$

SYNOPSIS...SMF
NEAR TERM...SMF/NIELD
SHORT TERM...SMF
LONG TERM...CP
AVIATION...JP

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