Area Forecast Discussion
Issued by NWS Northern Indiana

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203
FXUS63 KIWX 120040
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
740 PM EST THU FEB 11 2016

.SYNOPSIS...
ISSUED AT 334 PM EST THU FEB 11 2016

LAKE EFFECT SNOW SHOWERS WILL DISSIPATE THIS EVENING WITH
GENERALLY DRY AND COLD CONDITIONS OVERNIGHT. AN ARCTIC COLD FRONT
WILL MOVE ACROSS THE AREA ON FRIDAY, LIKELY ACCOMPANIED BY SNOW
SHOWERS. LAKE EFFECT SNOW WILL DEVELOP BEHIND THE FRONT BY FRIDAY
EVENING AND CONTINUE THROUGH SATURDAY AFTERNOON. LOWS TONIGHT WILL
BE NEAR 10 WITH HIGHS FRIDAY IN THE LOWER 20S.

&&

.UPDATE...
ISSUED AT 727 PM EST THU FEB 11 2016

LAKE EFFECT SNOW SHOWERS/FLURRIES WILL CONTINUE TO DIMINISH THIS
EVENING AS LOW LEVEL ANTICYCLONE BUILDS INTO THE REGION. SKIES
HAVE CLEARED FAIRLY QUICKLY ACROSS THE WEST THIS EVENING WHICH
HAVE ALLOWED TEMPS TO TAKE A SHARP DROP. LAKE EFFECT CLOUDS WILL
LIKELY LINGER ACROSS THE FAR NORTH INTO THE OVERNIGHT WHICH SHOULD
LIMIT TEMP DROPS SOMEWHAT...WITH ALSO AN INCREASE IN MID/HIGH
LEVEL CLOUDS OVERNIGHT. WOULD SUSPECT LOW TEMP MAY BE REACHED
AROUND MIDNIGHT OR IN THE EARLY PORTIONS OF THE OVERNIGHT HOURS
BEFORE BECOMING STEADY. MADE SOME SLIGHT ADJUSTMENTS TO MINS
TONIGHT BASED ON CURRENT TRENDS...MAINLY FOR SNOW COVERED AREAS
AWAY FROM LAKE EFFECT CLOUDS WHERE MORE SUBSTANTIAL MID/HIGH CLOUD
ARRIVAL SHOULD BE MORE DELAYED. OTHERWISE...NO SUBSTANTIAL
CHANGES TO PREVIOUS FORECAST WITH JUST A CORRESPONDING SLIGHT
DOWNWARD ADJUSTMENT TO POPS THIS EVENING.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 334 PM EST THU FEB 11 2016

SFC HIGH PRESSURE MOVG SE INTO THE OH VALLEY TODAY PROVIDING
SUBSIDENCE/DRYING AND BACKING WINDS WHICH SHOULD DIMINISH THE SCT
LAKE EFFECT/DIURNALLY DRIVEN SNOW SHOWERS/FLURRIES EARLY THIS
EVENING. WK SHRTWV TOPPING WRN RIDGE TODAY WILL DIVE RAPIDLY SE TO
THE LWR OH VALLEY BY FRIDAY MORNING AND TO THE MID ATLANTIC COAST
BY EVE. EXPECT INCREASING MID/HIGH CLOUDINESS TONIGHT AS THIS
SYSTEM APPROACHES WHICH COMBINED WITH WK WAA SHOULD LIMIT TEMP
FALLS OVERNIGHT.

SECOND STRONGER SHRTWV AND ASSOCIATED ARCTIC CDFNT WILL DROP SSE
ACROSS THE GRTLKS FRIDAY. THIS FRONT WILL LIKELY BE ACCOMPANIED BY
SNOW SHOWERS WITH GREATEST COVERAGE OVER THE NW WHERE THERE WILL BE
SOME LAKE ENHANCEMENT. WINDS WILL ALSO INCREASE, PRBLY LEADING TO
AREAS OF BLOWING SNOW, ESPECIALLY OVER THE NW WHERE CURRENT SNOW
PACK IS DEEPER AND MORE NEW SNOWFALL EXPECTED. HIGHS SHOULD BE IN
THE L20S WITH TEMPS PSBLY FALLING OFF A BIT DURING THE AFTN AS CAA
STRENGTHENS.

&&

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 334 PM EST THU FEB 11 2016

ANOTHER ARCTIC ONSLAUGHT AS STRONG SWD DROP FM POLAR EXTENSION OVER
CENTRAL HUDSON REACHES FAR SWRN QUEBEC/LK ONT/UPSTATE NY BY 12 UTC
SAT. RAPID LES RESPONSE ANTICIPATED AND LIKELY PEAKING 00-06 UTC SAT
AS LK INDUCED PARAMETERS PEAK WITH EQL TOPPING 10KFT AND CAPE VALUES
TO 600-650 J/KG WITH LWR 20C LK/8H DIFFERENTIALS. WITH TIME PRIMARY
SURFACE LOW UNDERGOES TRANSFER TO NEW ENGLAND COASTAL SYSTEM BY 12
UTC SAT...LARGELY SHEARING OUT WRN EXTENSION OF LAKE AGGREGATE TROF.
THIS ALONG WITH RELATIVELY LOW CP BULK MOISTURE AND COMMENSURATE
SHALLOW MOISTURE DEPTH AND SHALLOW DGZ WITH POOR LEVEL OF
SUPERSATURATION AND MAJORITY OF DEPTH IN SFC TO CLOUD BASE WITH
SUPERSATURATION ABOVE DGZ FOR INTRODUCTIONS OF COLUMNS AND SMALL
HEXAGONAL PLATES TO LEND INCREASINGLY LOWER SLR WITH TIME THROUGH
END OF ADVISORY LEVEL EVENT. STILL AMOUNT OF NEW SNOW ATOP
SUBSTANTIAL SNOWPACK TO AFFORD BLOWING SNOW POTENTIAL AND COLD
AIRMASS SUPPORTING MIN WIND CHILLS -5 TO -10 DURING LATTER PART OF
LES SNOW EVENT FOR A MULTI HAZARD ADVISORY. UNLIKE THE LAST
SUBSTANTIAL LONG DURATION LES EVENT HEIGHTS REBUILD AS ARCTIC
SURFACE RIDGE QUICKLY ENVELOPES UPPER GREAT LAKES SQUELCHING
RESPONSE LATE SAT AFTN/EVE. THEREAFTER MINOR WAVES FOR LOW POPS
ASSOCCD WITH POSSIBLE WEAK CLIPPER SYSTEMS DYS4-6 FOLLOWED BY
EXPECTED MINOR LES TUE NIGHT INTO WED AS ERN CONUS TROF DEEPENS AND
DRIVES APPALACHIAN TO NEW ENGLAND OR A NEAR COASTAL SYSTEM AROUND
MIDDLE OF NEXT WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 727 PM EST THU FEB 11 2016

LOW LEVEL RIDGE AXIS BUILDING INTO THE AREA HAS ALLOWED FOR RAPID
DOWNWARD TREND IN LAKE EFFECT PRECIP. THE THREAT OF LAKE EFFECT
SNOW SHOWERS AT KSBN APPEARS TO HAVE ENDED FOR THE REMAINDER OF
THE NIGHT. THE NEXT UPPER LEVEL TROUGH APPROACH THE MID MS RIVER
VALLEY WILL TAKE A MORE SOUTHERLY TRACK THAT SHOULD KEEP ANY LATE
NIGHT CHANCES OF LIGHT SNOW SOUTH OF THE TERMINALS. THE NEXT
NORTHERN STREAM VORT MAX WILL DIG ACROSS THE WESTERN GREAT LAKES
FRIDAY MORNING BRINGING A REINFORCING COLD FRONTAL PASSAGE. SNOW
SHOWERS ARE POSSIBLE ALONG THIS TROUGH AXIS FRIDAY MORNING/EARLY
AFTERNOON...WITH A TRANSITION TO LAKE EFFECT SNOW SHOWERS TOWARD
THE END OF THE PERIOD. DEEPENING MIXED LAYER FRIDAY
AFTERNOON/EVENING WITH COLD ADVECTION SHOULD RESULT IN NORTHWEST
WIND GUSTS INTO THE 25 TO 30 KNOT RANGE FOR A TIME FRIDAY
AFTERNOON/EARLY FRIDAY EVENING BEFORE SETTLING MORE INTO THE 20 TO
25 KNOT RANGE BEYOND THIS FORECAST VALID PERIOD. DID TREND TO IFR
CONDITIONS AT KSBN TOWARD THE END OF THE PERIOD AS LAKE EFFECT
SNOW SHOWERS INCREASE AND SYNOPTIC TROUGH APPROACHES. SHORT LIVED
IFR VSBYS ARE ALSO POSSIBLE WITH ANY SNOW SHOWERS ASSOCIATED WITH
TROUGH AXIS LATE FRIDAY MORNING/AFTERNOON.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY FROM 7 AM EST /6 AM CST/ FRIDAY TO 4 PM
     EST /3 PM CST/ SATURDAY FOR INZ003>005.

MI...WINTER WEATHER ADVISORY FROM 7 AM FRIDAY TO 4 PM EST SATURDAY
     FOR MIZ077>079.

OH...NONE.
LM...HEAVY FREEZING SPRAY WARNING FROM 7 PM FRIDAY TO 7 AM EST
     SATURDAY FOR LMZ043-046.

     GALE WARNING FROM 3 PM FRIDAY TO 5 AM EST SATURDAY FOR LMZ043-
     046.

&&

$$

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


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