Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 110151
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
851 PM EST WED FEB 10 2016

.SYNOPSIS...
ISSUED AT 347 PM EST WED FEB 10 2016

LAKE EFFECT SNOW SHOWERS WILL PERSIST OVERNIGHT WITH A COUPLE MORE
INCHES IN THE LAKE EFFECT REGION. THE SNOW SHOWERS WILL TAPER
THROUGH THE DAY ON THURSDAY. LOWS TONIGHT WILL RANGE FROM THE
SINGLE DIGITS WELL AWAY FROM LAKE MICHIGAN TO THE TEENS NEAR THE
LAKE. HIGHS ON THURSDAY WILL ONLY REACH INTO THE LOWER TO MIDDLE
20S. ANOTHER ROUND OF LAKE EFFECT SNOW SHOWERS IS EXPECTED FRIDAY
NIGHT INTO SATURDAY...THOUGH LIGHTER AMOUNTS ARE FORECAST.

&&

.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 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 705 PM EST WED FEB 10 2016

LITTLE CHANGE TO PREVIOUS FORECAST WITH LAKE EFFECT SNOW SHOWERS
CONTINUING AS THE MAIN AVIATION FORECAST CHALLENGE. MODERATE LAKE
INDUCED INSTABILITY WILL PERSIST THIS FORECAST PERIOD. NOT
EXPECTING AS MUCH IN THE WAY OF SYNOPTIC ENHANCEMENT AS IN THE
PREVIOUS 24 HOUR PERIOD...ALTHOUGH SHEARED VORT MAX SHOULD REACH
THE WESTERN GREAT LAKES LATE TONIGHT. SNOW SHOWERS TO CONTINUE
THROUGH MUCH OF THE NIGHT AT KSBN WITH FLUCTUATIONS BETWEEN IFR
AND MVFR VSBYS EXPECTED. MVFR VSBYS IN SNOW SHOWERS EXPECTED AT
KFWA EARLY EVENING...WITH CONFIDENCE IN VSBY RESTRICTIONS AT KFWA
LOWER FOR THE REMAINDER OF THE PERIOD AS BULK OF LAKE EFFECT SNOW
SHOWERS SHOULD REMAIN TO THE NORTHWEST. MVFR CIGS ARE EXPECTED TO
PERSIST AT TERMINALS THROUGH MUCH OF THE PERIOD...WITH GREATER
CONFIDENCE AT KSBN. WEST WINDS OF 10 TO 15 KNOTS SHOULD SETTLE
AROUND 10 KNOTS TONIGHT AND CONTINUE THROUGH THURSDAY AFTERNOON.


&&

.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...MURPHY
SHORT TERM...JT
LONG TERM...MURPHY
AVIATION...MARSILI


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