Area Forecast Discussion
Issued by NWS Indianapolis, IN

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136
FXUS63 KIND 091010
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
510 AM EST TUE FEB 9 2016

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

&&

.SYNOPSIS...
ISSUED AT 313 AM EST TUE FEB 9 2016

WINTER WILL CONTINUE ITS HOLD ON CENTRAL INDIANA WITH BELOW NORMAL
TEMPERATURES THROUGH THE WEEKEND. A COUPLE OF ARCTIC BLASTS WILL
PROVIDE LOWS IN THE SINGLE DIGITS AND HIGHS IN THE TEENS A COUPLE OF
TIMES DURING THE WEEK. SNOW SHOWERS WILL END ON WEDNESDAY...BUT
PERIODIC SNOW CHANCES WILL RETURN FRIDAY AND AGAIN AROUND MONDAY.

&&

.NEAR TERM.../TODAY/
ISSUED AT 313 AM EST TUE FEB 9 2016

EARLY THIS MORNING...SCATTERED SNOW SHOWERS CONTINUE ACROSS THE AREA
WITH AN UPPER LOW TO OUR NORTHEAST. MORE PERSISTENT SNOW BANDS WERE
JUST TO OUR EAST IN OHIO...WHERE MUCH HIGHER ACCUMULATIONS WERE
OCCURRING.

RADAR SHOWS AN AREA OF SNOW SHOWERS ACROSS NORTHERN ILLINOIS AND
NORTHERN INDIANA THAT SHOULD WORK INTO THE NORTHEAST FORECAST AREA
EARLY THIS MORNING. MEANWHILE OTHER AREAS OF SNOW SHOWERS ACROSS
WESTERN ILLINOIS LOOK TO SLIDE JUST SOUTHWEST OF THE FORECAST AREA.
WILL GO LIKELY POPS THIS MORNING FAR NORTHEAST AND HIGH CHANCE POPS
ELSEWHERE.

THIS AFTERNOON...EXPECT MORE SNOW SHOWERS TO DEVELOP WITH HEATING.
IN ADDITION...ANOTHER PIECE OF UPPER ENERGY AND A SURFACE TROUGH
LOOK TO MOVE THROUGH. THIS TOO WILL HELP INCREASE SNOW SHOWER
COVERAGE. THUS WENT LIKELY POPS THIS AFTERNOON ACROSS MOST OF THE
AREA.

SNOW SQUALL PARAMETER INDICATES GREATEST THREAT FOR INTENSE SQUALLS
WILL LIE TO THE NORTH AND EAST OF THE AREA. SHORT RANGE ENSEMBLES
SHOW THAT ODDS OF VISIBILITY OF A MILE OR LESS IS LOW.

QPF IS EXPECTED TO BE LOW AS WELL. EXPECTING...ON AVERAGE...AN INCH
OR LESS 12Z-24Z. THUS WITH THE LOW COVERAGE OF SQUALLS EXPECTED AND
THE LOW QPF AMOUNTS...HAVE DECIDED AGAINST GOING WITH AN ADVISORY
TODAY. THERE WILL STILL BE SLICK SPOTS ON ROADS AND VISIBILITY DOWN
TO AROUND 2 MILES THOUGH. IT IS FEBRUARY IN INDIANA AFTER ALL. WILL
CONTINUE WITH A SPECIAL WEATHER STATEMENT HIGHLIGHTING THE THREATS.

WITH THE CLOUDS AND SNOW AROUND FEEL THAT MOS IS TOO HIGH WITH
TEMPERATURES TODAY. TRIMMED THEM A BIT.

&&

.SHORT TERM.../TONIGHT THROUGH THURSDAY NIGHT/
ISSUED AT 313 AM EST TUE FEB 9 2016

FOCUS REMAINS ON SNOW CHANCES THROUGH THE PERIOD. MODELS ARE CLOSE
ENOUGH TO USE A BLEND.

ALTHOUGH HEIGHTS INCREASE TONIGHT...THERE LOOKS TO BE A PERIOD OF
POSITIVE VORTICITY ADVECTION THIS EVENING. IN ADDITION...NORTHEAST
FORECAST AREA COULD SEE LAKE ENHANCED SNOW SHOWERS. THUS RAISED
MODEL POPS AND WENT LIKELY FAR NORTHEAST...TO HIGH CHANCE CATEGORY
POPS MUCH OF THE REMAINDER OF THE AREA...TO LOW CHANCE FAR WEST.
CHANCES WILL DECREASE THROUGH THE NIGHT AS THE SYSTEM STARTS TO EXIT.

BY WEDNESDAY MORNING...ONLY CHANCE TO SLIGHT CHANCE POPS ARE
WARRANTED ACROSS THE EASTERN HALF OF THE AREA WITH AGAIN THE THREAT
OF SOME LAKE ENHANCED SNOW SHOWERS. CONTINUED THE LOWERING OF POPS
THROUGH THE DAY AS THE SYSTEM PULLS AWAY. HOWEVER KEPT CHANCE POPS
ALL DAY FAR NORTHEAST DUE TO THE LAKE SNOW SHOWER THREAT.

WEDNESDAY NIGHT A QUICK MOVING SYSTEM WILL REMAIN JUST SOUTHEAST OF
THE AREA. WILL KEEP CLOUD COVER HIGH EARLY WITH THE SYSTEM...BUT
FEEL THAT ANY SNOW WILL REMAIN OUT OF CENTRAL INDIANA.

THE AREA WILL REMAIN IN BETWEEN SYSTEMS THURSDAY AND THURSDAY
NIGHT...SO CONTINUED WITH A DRY FORECAST THEN.

GENERALLY STUCK WITH A MODEL BLEND FOR TEMPERATURES THROUGH THE
PERIOD. THE ARCTIC AIRMASS WILL PROVIDE WIND CHILLS BELOW ZERO MID
WEEK.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
ISSUED AT 245 AM EST TUE FEB 9 2016

BIG MODEL AND ENSEMBLE DIFFERENCES WILL BE A MAJOR HURDLE TO PARTS
OF THE LONG TERM FORECAST INCLUDING POPS AND TEMPERATURES.

VERY FAST NORTHWEST FLOW ALOFT WILL BE IN PLACE AT THE START OF THE
LONG TERM. THIS IS CAUSING SIGNIFICANT SHEARING OF ANY PACIFIC WAVE
THAT CRESTS THE UPPER WESTERN RIDGE AND HEADS TOWARDS THE OHIO
VALLEY. THAT SAID MODELS...ESPECIALLY THE 00Z ECMWF...CONTINUE TO
BRING SOME SNOW TO THE FORECAST AREA ON FRIDAY. WITH CONFIDENCE
LOW...WILL CONTINUE WITH SMALL SNOW CHANCES ON FRIDAY. THEN...MODELS
AGREE THAT JAMES BAY UPPER LOW WILL DROP SOUTHEAST ACROSS NEW
ENGLAND ON SATURDAY. THIS WILL BRING ANOTHER SHOT OF COLD TO THE
OHIO VALLEY. ARCTIC HIGH WILL THE MOVE OVER THE OHIO VALLEY AND
GREAT LAKES ON SATURDAY WITH SOUTHERLY FLOW ON THE BACK SIDE TO
RETURN ON SUNDAY.

THE BIGGEST MODEL AND ENSEMBLE DIFFERENCES WILL BE WITH ANOTHER
WINTER STORM SYSTEM THAT WILL EFFECT CENTRAL INDIANA BY SUNDAY
NIGHT. MODELS MOVE A STRONGER WAVE OVER THE WESTERN RIDGE AND MOVE
IT TO ACROSS THE LOWER GREAT LAKES AND OHIO VALLEY SUNDAY NIGHT INTO
MONDAY. THE 00Z GFS WAS BRINGING A TRAILING FRONT ACROSS ON MONDAY
WITH THE ASSOCIATED SURFACE LOW OVER NORTHERN MICHIGAN.
HOWEVER...THE 00Z ECMWF HAD THE MAIN SURFACE LOW LIFTING NORTHEAST
ACROSS SOUTHERN AND EASTERN INDIANA SUNDAY NIGHT INTO MONDAY. THE
EURO SOLUTION WOULD BRING DECENT SNOW AMOUNTS TO CENTRAL INDIANA
WITH LESSER AMOUNTS IF THE GFS VERIFIES. EITHER WAY...WILL LEAVE
SNOW CHANCES IN THE FORECAST.

TEMPERATURES FRIDAY NIGHT AND SATURDAY WILL LIKELY DEPEND A LOT ON
SNOW COVER AS THERE SHOULD BE AT LEAST PARTIAL CLEARING IN THE WAKE
OF THE CLIPPER AND AS ARCTIC HIGH PRESSURE APPROACHES. NUDGED
REGIONAL BLEND TEMPERATURES DOWN A COUPLE OF DEGREES FOR THAT
PERIOD...BUT IT MAY NOT BE ENOUGH. TEMPERATURES ARE ONLY EXPECTED TO
REBOUND TO CLOSE TO NORMAL BY EARLY NEXT WEEK PER THE BLEND.

&&

.AVIATION /DISCUSSION FOR THE 09/1200Z TAF ISSUANCE/...
ISSUED AT 510 AM EST TUE FEB 9 2016

GOOD CONFIDENCE THAT COLD CYCLONIC FLOW AND LOW LEVEL MOISTURE WILL
CONTINUE TO GENERATE MOSTLY MVFR CEILINGS TODAY WITH SNOW SHOWERS
INCREASING DURING THE AFTERNOON. BRIEF IFR CONDITIONS ARE LIKELY
WITHIN ANY SNOW SHOWER...ESPECIALLY AT LAF AND IND. WILL ALSO LIKELY
NEED A TEMPO IFR CEILING AT IND THROUGH 14Z OR SO BASED ON TRENDS
AND LAMP IFR PROBABILITIES.

THE SNOW SHOWERS SHOULD COME TO AN END FROM SOUTHWEST TO NORTHEAST
TONIGHT AS THE BACK END OF THE BROAD TROUGH APPROACHES. WILL STILL
HOLD ON TO MVFR CEILINGS THROUGH THE NIGHT...HOWEVER PER MODEL RH
TIME SECTIONS AND LAMP AND SREF MVFR PROBABILITIES.

WEST TO NORTHWEST WINDS 10 TO 15 KNOTS WILL GUST TO NEAR 20 KNOTS
THROUGH TONIGHT.

&&

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

&&

$$

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



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