Area Forecast Discussion
Issued by NWS Northern Indiana

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938
FXUS63 KIWX 110513
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1213 AM EST THU FEB 11 2016

.SYNOPSIS...
ISSUED AT 1210 AM EST THU FEB 11 2016

LAKE EFFECT SNOW SHOWERS WILL CONTINUE TODAY FOR AREAS MAINLY
NORTH OF US 30. HIGHS TODAY WILL REACH THE LOW TO MID 20S.
ANOTHER ROUND OF LAKE EFFECT SNOW SHOWERS IS EXPECTED LATER FRIDAY
INTO SATURDAY...THOUGH LIGHTER AMOUNTS ARE FORECAST.
OTHERWISE...IT WILL REMAIN COLD THROUGH THE WEEKEND WITH HIGHS
GENERALLY IN THE TEENS AND 20S.

&&

.UPDATE...
ISSUED AT 836 PM EST WED FEB 10 2016

LAKE EFFECT SNOW SHOWERS WILL CONTINUE OVERNIGHT WITH MODERATE
LAKE INDUCED INSTABILITY PERSISTING. STEEP LOW LEVEL LAPSE RATES
HAVE ALLOWED FOR CONTINUED SIGNIFICANT INLAND PENETRATION WITH THE
STRONGEST OF THESE BANDS AT 0130Z FROM THREE RIVERS MI TO
NORTHWEST OF DEFIANCE. THIS BAND ALSO APPEARS TO BE ALIGNED WITH
BETTER LAKE SUPERIOR CONNECTION. MAIN TWEAK FOR EVENING UPDATE WAS
TO INCREASE ACCUMULATIONS SLIGHTLY ACROSS THE FAR NORTH/NORTHEAST
TO ACCOUNT FOR ONGOING MORE PRONOUNCED BANDING. OTHERWISE...WILL
CONTINUE WITH CATEGORICAL POPS FOR FAVORED LAKE EFFECT AREAS WITH
LITTLE CHANGE IN LAKE INDUCED INSTABILITY MAGNITUDE OVERNIGHT.
GREAT LAKES MID LEVEL TROUGH WILL BEGIN TO PULL OFF TO THE EAST
OVERNIGHT WITH INCREASING MID LEVEL SUBSIDENCE IN THE 06-12Z
TIMEFRAME. MID LEVEL DRY AIR MAY ALSO BECOME AN INCREASING FACTOR
TO CONSIDER OVERNIGHT INTO EARLY THURSDAY MORNING. PREVIOUS
FORECAST THOUGHTS STILL APPEAR TO BE VALID WITH ABOVE FACTORS
SUPPORTING GENERAL DOWNWARD TREND IN INTENSITY LATE
TONIGHT/THURSDAY MORNING AS INVERSION HEIGHTS BEGIN TO LOWER MORE
SHARPLY.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 337 PM EST WED FEB 10 2016

NW FLOW AND LAKE INDUCED MODERATE INSTABILITY WITH DELTA T`S NEAR
20C AND 300-400J/KG CAPE SHOULD ALLOW LAKE EFFECT SNOW SHOWERS TO
PERSIST OVERNIGHT AND AT LEAST THROUGH MIDDAY THURSDAY. LOWERING
INVERSION, DRY AIR ADVECTION, AND BACKING WINDS SHOULD CAUSE A
DIMINISHING TREND TO THE LAKE EFFECT SNOW BEGINNING LATE TONIGHT
AND CONTG THROUGH THE DAY THU. ADDITIONAL ACCUMS TONIGHT EXPECTED
TO BE SIMILAR TO TODAY, IN THE 1-3" RANGE ACROSS THE NW PORTION OF
THE CWA AND GENERALLY <1" FARTHER INLAND, WITH AN ADDITIONAL INCH
OR LESS IN THE WINTER WX ADVISORY AREA ON THU. THIS SHOULD BRING
THE STORM TOTAL FOR THIS PROLONGED EVENT UP TO AROUND A FOOT IN
SOME LOCATIONS IN THE ADVISORY AREA.

GRADIENT MIXING AND SOME CLOUD COVER SHOULD LIMIT RADIATIONAL
COOLING AGAIN TONIGHT. LOWS EXPECTED TO BE IN THE HIGH SINGLE
DIGITS SW AND NE WHERE PARTIAL CLEARING EXPECTED, AND IN THE 10-15
RANGE OVER THE REST OF THE CWA WHICH SHOULD STAY MOSTLY CLOUDY. WK
WAA AND A LITTLE MORE SUNSHINE THU SHOULD RESULT IN A LITTLE
WARMER TEMPS THAN TODAY WITH HIGHS IN THE L-M20S.

&&

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 337 PM EST WED FEB 10 2016

BACKING FLOW AND LOWERING INVERSION HEIGHTS TO STIFFLE LES
PRODUCTION ALONG SOUTHERN PERIPHERY LATE THU/THU NIGHT...
RETREATING NWD INTO MI. WEAK CLIPPER SYSTEM DIVES TOWARD OHIO
VALLEY EARLY FRIDAY IN TEMPORARY RELAXATION IN SOUTHERN PERIPHERY
OF GREAT LAKES. HOWEVER AS A STRONG 65N ORIGINATING VORTEX PLUNGES
SSEWD INTO RESPONSE TO HIGH AMPLITUDE CANADIAN ROCKIES RIDGING.
MORE ARCTIC FRONTAL FORCED SHSN INTO FRI AFTN FOLLOWED BY RETURN
OF LES. HAVE RAMPED LES POPS SUBSTANTIALLY FRI NIGHT INTO SAT WITH
NEAR 20/LWR 20S DELTA T. LESS REMARKABLE MOISTURE DEPTH AND
THIN/MOSTLY SUB CLOUD DGZ TO AFFORD TO LIKELY KEEP OVERALL
QPF/ACCUMS/SLR IN CHECK...THOUGH WOULD NOT RULE OUT POTENTIAL FOR
TARGETED ADV. COLDEST TEMPS SAT NIGHT IN HEART OF 925MB THERMAL
TROF WITH LES RESPONSE QUICKLY WANING AMID DESCENDING INVERSION
HEIGHTS/NRLY VEERING FLOW LIKELY PUSHING LES INTO NWRN IN/NERN IL.
FLATTER MORE PROGRESSIVE FLOW INTO MID WEEK TO EMBARQ OF THERMAL
MODERATION ALONG WITH EPISODIC LOW CHC PRECIP.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1210 AM EST THU FEB 11 2016

LAKE EFFECT SHSN WILL CONTINUE TO IMPACT MAINLY KSBN WITH VARIABLE
FLIGHT CONDITIONS (VIS RANGING MVFR TO LIFR) THROUGH AT LEAST THE
EARLY AFTERNOON. LESSER IMPACTS EXPECTED AT KFWA BUT COULD SEE
BRIEF IFR/MVFR RESTRICTIONS WITH ANY SHSN THROUGH MID AFTERNOON.
BACKING/WEAKENING WINDS WILL ALLOW ANY LAKE EFFECT ACTIVITY TO
DIMINISH BY THIS EVENING WITH VFR CONDITIONS ANTICIPATED.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL 10 AM EST /9 AM CST/ THURSDAY FOR
     INZ003>005.

MI...WINTER WEATHER ADVISORY UNTIL 10 AM EST THURSDAY FOR MIZ077>079.

OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 PM EST THURSDAY FOR LMZ043-046.

&&

$$

UPDATE...MARSILI
SYNOPSIS...STEINWEDEL
SHORT TERM...JT
LONG TERM...MURPHY
AVIATION...STEINWEDEL


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