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000
FXUS63 KIWX 181735
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1235 PM EST THU DEC 18 2014

.SYNOPSIS...
ISSUED AT 1240 AM EST THU DEC 18 2014

LIGHT LAKE EFFECT SNOW SHOWERS ARE POSSIBLE TODAY INTO THIS
EVENING AS A TROF MOVES SOUTH OVER LOWER MICHIGAN INTO NORTHERN
INDIANA. LITTLE IF ANY SNOW ACCUMULATION IS EXPECTED. HIGHS TODAY
AND FRIDAY WILL BE AROUND 30 TO 35. LOWS TONIGHT WILL BE IN THE
20S.

&&

.UPDATE...
ISSUED AT 950 AM EST THU DEC 18 2014

BAND OF LAKE EFFECT SNOW ASSOCIATED WITH SFC TROF MOVG SOUTH THROUGH
SRN MI/LM AND WK LAKE INDUCED INSTABILITY PASSED THROUGH MKG THIS
PAST HOUR WITH APPARENTLY SOME LIGHT ACCUM PER ASOS OB. THIS BAND IS
EXPECTED TO REMAIN NORTH OF OUR CWA THROUGH DAYLIGHT HOURS TODAY BUT
SHOULD REACH OUR SWRN MI COUNTIES EARLY THIS EVE. KEPT A CHC OF
PRECIP IN THE FCST ACROSS NRN PORTION OF THE CWA DUE TO WK LIFT
ASSOCIATED WITH WKNG UPR TROF MOVG EAST INTO THE OH VALLEY AND SOME
WK LAKE ENHANCEMENT. HWVR CHANGED PRECIP WORDING FOR THE DAYTIME
PERIOD TO FLURRIES/FREEZING DRIZZLE AS EXPECT A NON-MEASURABLE EVENT
THROUGH EARLY EVE AND MOISTURE ON MORNING DTX SOUNDING CONFINED TO
JUST BLO DGZ. GIVEN SFC TEMP-DWPT SPREADS AROUND 5F... DO NOT EXPECT
FREEZING DRIZZLE WILL BE HEAVY ENOUGH TO CAUSE GLAZED SURFACES...
JUST SOME SMALL LIQUID DROPLETS ON THE WINDSHIELD ALONG WITH THE
SNOW GRAINS.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 358 AM EST THU DEC 18 2014

UPPER AIR SOUNDINGS FROM YESTERDAY EVENING AND OVERNIGHT AIRCRAFT
OBSERVATIONS SHOWED AN INCREASING DEPTH TO THE INVERSION FROM
SOUTHWEST TO NORTHEAST. THE BASE OF THE INVERSION RANGED FROM LESS
THEN 2000 FEET AT LINCOLN IL/ILX...TO 4000 FEET AT FT WAYNE TO 5000
FEET NEAR DETROIT. OVERNIGHT SATELLITE SHOWED CLOUDS FILLING IN OVER
LAKE MICHIGAN WHERE THE INVERSION HEIGHT WAS ONLY 3000 FEET. THIS
LOW INVERSION HEIGHT WAS LIMITING LAKE EFFECT SNOW SHOWERS.  A
SURFACE TROF WILL MOVE SOUTH ACROSS LOWER MICHIGAN THIS AFTERNOON
AND INTO NORTHERN INDIANA THIS EVENING...AND HELP TO KEEP A SMALL
CHANCE FOR SNOW SHOWERS LATE TODAY AND EARLY TONIGHT. OTHERWISE...
KEPT LOW CHANCES FOR LIGHT LAKE EFFECT SNOW SHOWERS GIVEN A LOW
INVERSION HEIGHT AND A MARGINAL FETCH WITH MEAGER DELTA T VALUES
AROUND 11C. BELIEVE IT WILL BE DIFFICULT TO BREAK OUT OF THE LOW
CLOUDS WITH THIS PATTERN THROUGH TONIGHT. GIVEN ABUNDANT CLOUD
COVER...KEPT TEMPERATURES COLD TODAY WITH HIGHS ONLY IN THE LOWER
30S.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 358 AM EST THU DEC 18 2014

MOST IMPORTANT INFORMATION FIRST SO THIS LONG TERM WILL BEGIN WITH
DISCUSSION OF POSSIBLE WINTER STORM NEXT WEEK. HYPE ALREADY WELL
UNDERWAY BUT A LOT OF UNCERTAINTY REMAINS WITH RESPECT TO THE VERY
IMPORTANT AND CRITICAL DETAILS OF WHEN AND WHERE THIS STORM WILL
CREATE IMPACTS. CAUTIOUS BUT INFORMATIVE APPROACH WARRANTED GIVEN
THE DAY 6 TO 7 TIME FRAME AND A VERY ENERGETIC PACIFIC JET STREAM
WHICH IS POORLY SAMPLED. THUS NUMEROUS CRITICAL CHANGES AND
DEVIATIONS IN MODEL SOLUTIONS EXPECTED WITH EACH ITERATION OVER THE
NEXT SEVERAL DAYS. THE BROAD SYNOPTIC AGREEMENT AMONG MODELS DOES
GIVE HIGHER THAN NORMAL CONFIDENCE THAT A SUBSTANTIAL STORM SYSTEM WILL
IMPACT SOME PART OF THE EASTERN CONUS REGION BY CHRISTMAS.
HOWEVER...ALREADY SEEING MODEL ADJUSTMENTS IN POTENTIAL TIMING AND
TRACK OF SYSTEM AS WELL AS HOW FAST COLDER AIR WILL SWEEP IN.
CONFIDENCE REMAINS BELOW NORMAL ON IMPORTANT DETAILS SUCH AS
TRACK...PCPN TYPE AND AMOUNTS. LATEST 00Z MODELS TRENDING SYSTEM
WESTWARD AS THEY TEND TO DO WITH DYNAMICALLY STRONG AND NEGATIVELY
TILTED SYSTEMS. CURRENT MODEL RUNS DO BRING COLD AIR IN ON CHRISTMAS
EVE SO KEPT PCPN TYPE ALL SNOW IN THIS PERIOD FOR NOW. MODELS STILL
SHOWING A VERY STRONG LOW DEVELOPING WITH TIGHT GRADIENT AS BLOCKY
PATTERN STALLS SYSTEM OVER GREAT LAKES REGION. ANY SNOW THAT DOES
FALL BY CHRISTMAS WILL CERTAINLY CREATE TRAVEL ISSUES AND HAVE
SIGNIFICANT IMPACTS DUE TO BLOWING AND DRIFTING. THIS REMAINS WORTHY
OF MENTION IN HWO BUT RESTRAINT SHOULD BE EXERCISED FOR NOW IN THE
FORECASTS OF TRACK AND SNOW AMOUNTS GIVEN LITTLE SKILL AT THIS TIME
RANGE.

OTHERWISE A RATHER BENIGN LONG TERM PERIOD EXPECTED LEADING UP TO
THIS POTENTIAL STORM. SEASONABLE TEMPERATURES TO START THE PERIOD
FRIDAY WITH A SUBTLE WARMING TREND INTO EARLY NEXT WEEK. SEVERAL
WEAK SHORT WAVES AND TRAPPED LOW LEVEL MOISTURE BENEATH INVERSION TO
LIKELY KEEP SKIES AT LEAST PARTLY CLOUDY IF NOT MOSTLY CLOUDY
THROUGH THE PERIOD. INITIAL SHORT WAVE AND MOISTURE SURGE MONDAY
WILL BRING INITIAL CHANCES OF PCPN INTO THE REGION.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1229 PM EST THU DEC 18 2014

WKNG SHRTWV MOVG EAST THROUGH THE OH VALLEY TODAY PROVIDING WK LIFT
WHICH COMBINED WITH LINGERING LOW LEVEL MOISTURE WAS CAUSING SOME
LIGHT SNOW WITH OCNL MVFR VSBY RESTRICTIONS. LACK OF MID LEVEL
MOISTURE SUGGESTS SOME POTENTIAL FOR VERY LIGHT -FZDZ AS WELL BUT
GIVEN PREDOMINANTLY -SN SFC OBS ATTM OPTED TO KEEP THIS OUT OF THE
18Z TAF. A BAND OF LAKE ENHANCED -SHSN ALONG A WK TROF MOVG SOUTH
ACROSS SRN LAKE MICHIGAN IS EXPECTED TO IMPACT SBN TONIGHT WITH A
BRIEF PERIOD OF -SHSN WITH MVFR VSBY RESTRICTIONS AND PSBLY LIGHT
ACCUMS. OTRWS LOW CLOUDS SHOULD REMAIN TRAPPED BENEATH INVERSION
THROUGH TONIGHT... WITH DIMINISHING CLOUD TEND FRIDAY AS DRIER AIR
FILTERS IN.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

UPDATE...JT
SYNOPSIS...SKIPPER
SHORT TERM...SKIPPER
LONG TERM...LASHLEY
AVIATION...JT


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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000
FXUS63 KIWX 181735
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1235 PM EST THU DEC 18 2014

.SYNOPSIS...
ISSUED AT 1240 AM EST THU DEC 18 2014

LIGHT LAKE EFFECT SNOW SHOWERS ARE POSSIBLE TODAY INTO THIS
EVENING AS A TROF MOVES SOUTH OVER LOWER MICHIGAN INTO NORTHERN
INDIANA. LITTLE IF ANY SNOW ACCUMULATION IS EXPECTED. HIGHS TODAY
AND FRIDAY WILL BE AROUND 30 TO 35. LOWS TONIGHT WILL BE IN THE
20S.

&&

.UPDATE...
ISSUED AT 950 AM EST THU DEC 18 2014

BAND OF LAKE EFFECT SNOW ASSOCIATED WITH SFC TROF MOVG SOUTH THROUGH
SRN MI/LM AND WK LAKE INDUCED INSTABILITY PASSED THROUGH MKG THIS
PAST HOUR WITH APPARENTLY SOME LIGHT ACCUM PER ASOS OB. THIS BAND IS
EXPECTED TO REMAIN NORTH OF OUR CWA THROUGH DAYLIGHT HOURS TODAY BUT
SHOULD REACH OUR SWRN MI COUNTIES EARLY THIS EVE. KEPT A CHC OF
PRECIP IN THE FCST ACROSS NRN PORTION OF THE CWA DUE TO WK LIFT
ASSOCIATED WITH WKNG UPR TROF MOVG EAST INTO THE OH VALLEY AND SOME
WK LAKE ENHANCEMENT. HWVR CHANGED PRECIP WORDING FOR THE DAYTIME
PERIOD TO FLURRIES/FREEZING DRIZZLE AS EXPECT A NON-MEASURABLE EVENT
THROUGH EARLY EVE AND MOISTURE ON MORNING DTX SOUNDING CONFINED TO
JUST BLO DGZ. GIVEN SFC TEMP-DWPT SPREADS AROUND 5F... DO NOT EXPECT
FREEZING DRIZZLE WILL BE HEAVY ENOUGH TO CAUSE GLAZED SURFACES...
JUST SOME SMALL LIQUID DROPLETS ON THE WINDSHIELD ALONG WITH THE
SNOW GRAINS.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 358 AM EST THU DEC 18 2014

UPPER AIR SOUNDINGS FROM YESTERDAY EVENING AND OVERNIGHT AIRCRAFT
OBSERVATIONS SHOWED AN INCREASING DEPTH TO THE INVERSION FROM
SOUTHWEST TO NORTHEAST. THE BASE OF THE INVERSION RANGED FROM LESS
THEN 2000 FEET AT LINCOLN IL/ILX...TO 4000 FEET AT FT WAYNE TO 5000
FEET NEAR DETROIT. OVERNIGHT SATELLITE SHOWED CLOUDS FILLING IN OVER
LAKE MICHIGAN WHERE THE INVERSION HEIGHT WAS ONLY 3000 FEET. THIS
LOW INVERSION HEIGHT WAS LIMITING LAKE EFFECT SNOW SHOWERS.  A
SURFACE TROF WILL MOVE SOUTH ACROSS LOWER MICHIGAN THIS AFTERNOON
AND INTO NORTHERN INDIANA THIS EVENING...AND HELP TO KEEP A SMALL
CHANCE FOR SNOW SHOWERS LATE TODAY AND EARLY TONIGHT. OTHERWISE...
KEPT LOW CHANCES FOR LIGHT LAKE EFFECT SNOW SHOWERS GIVEN A LOW
INVERSION HEIGHT AND A MARGINAL FETCH WITH MEAGER DELTA T VALUES
AROUND 11C. BELIEVE IT WILL BE DIFFICULT TO BREAK OUT OF THE LOW
CLOUDS WITH THIS PATTERN THROUGH TONIGHT. GIVEN ABUNDANT CLOUD
COVER...KEPT TEMPERATURES COLD TODAY WITH HIGHS ONLY IN THE LOWER
30S.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 358 AM EST THU DEC 18 2014

MOST IMPORTANT INFORMATION FIRST SO THIS LONG TERM WILL BEGIN WITH
DISCUSSION OF POSSIBLE WINTER STORM NEXT WEEK. HYPE ALREADY WELL
UNDERWAY BUT A LOT OF UNCERTAINTY REMAINS WITH RESPECT TO THE VERY
IMPORTANT AND CRITICAL DETAILS OF WHEN AND WHERE THIS STORM WILL
CREATE IMPACTS. CAUTIOUS BUT INFORMATIVE APPROACH WARRANTED GIVEN
THE DAY 6 TO 7 TIME FRAME AND A VERY ENERGETIC PACIFIC JET STREAM
WHICH IS POORLY SAMPLED. THUS NUMEROUS CRITICAL CHANGES AND
DEVIATIONS IN MODEL SOLUTIONS EXPECTED WITH EACH ITERATION OVER THE
NEXT SEVERAL DAYS. THE BROAD SYNOPTIC AGREEMENT AMONG MODELS DOES
GIVE HIGHER THAN NORMAL CONFIDENCE THAT A SUBSTANTIAL STORM SYSTEM WILL
IMPACT SOME PART OF THE EASTERN CONUS REGION BY CHRISTMAS.
HOWEVER...ALREADY SEEING MODEL ADJUSTMENTS IN POTENTIAL TIMING AND
TRACK OF SYSTEM AS WELL AS HOW FAST COLDER AIR WILL SWEEP IN.
CONFIDENCE REMAINS BELOW NORMAL ON IMPORTANT DETAILS SUCH AS
TRACK...PCPN TYPE AND AMOUNTS. LATEST 00Z MODELS TRENDING SYSTEM
WESTWARD AS THEY TEND TO DO WITH DYNAMICALLY STRONG AND NEGATIVELY
TILTED SYSTEMS. CURRENT MODEL RUNS DO BRING COLD AIR IN ON CHRISTMAS
EVE SO KEPT PCPN TYPE ALL SNOW IN THIS PERIOD FOR NOW. MODELS STILL
SHOWING A VERY STRONG LOW DEVELOPING WITH TIGHT GRADIENT AS BLOCKY
PATTERN STALLS SYSTEM OVER GREAT LAKES REGION. ANY SNOW THAT DOES
FALL BY CHRISTMAS WILL CERTAINLY CREATE TRAVEL ISSUES AND HAVE
SIGNIFICANT IMPACTS DUE TO BLOWING AND DRIFTING. THIS REMAINS WORTHY
OF MENTION IN HWO BUT RESTRAINT SHOULD BE EXERCISED FOR NOW IN THE
FORECASTS OF TRACK AND SNOW AMOUNTS GIVEN LITTLE SKILL AT THIS TIME
RANGE.

OTHERWISE A RATHER BENIGN LONG TERM PERIOD EXPECTED LEADING UP TO
THIS POTENTIAL STORM. SEASONABLE TEMPERATURES TO START THE PERIOD
FRIDAY WITH A SUBTLE WARMING TREND INTO EARLY NEXT WEEK. SEVERAL
WEAK SHORT WAVES AND TRAPPED LOW LEVEL MOISTURE BENEATH INVERSION TO
LIKELY KEEP SKIES AT LEAST PARTLY CLOUDY IF NOT MOSTLY CLOUDY
THROUGH THE PERIOD. INITIAL SHORT WAVE AND MOISTURE SURGE MONDAY
WILL BRING INITIAL CHANCES OF PCPN INTO THE REGION.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1229 PM EST THU DEC 18 2014

WKNG SHRTWV MOVG EAST THROUGH THE OH VALLEY TODAY PROVIDING WK LIFT
WHICH COMBINED WITH LINGERING LOW LEVEL MOISTURE WAS CAUSING SOME
LIGHT SNOW WITH OCNL MVFR VSBY RESTRICTIONS. LACK OF MID LEVEL
MOISTURE SUGGESTS SOME POTENTIAL FOR VERY LIGHT -FZDZ AS WELL BUT
GIVEN PREDOMINANTLY -SN SFC OBS ATTM OPTED TO KEEP THIS OUT OF THE
18Z TAF. A BAND OF LAKE ENHANCED -SHSN ALONG A WK TROF MOVG SOUTH
ACROSS SRN LAKE MICHIGAN IS EXPECTED TO IMPACT SBN TONIGHT WITH A
BRIEF PERIOD OF -SHSN WITH MVFR VSBY RESTRICTIONS AND PSBLY LIGHT
ACCUMS. OTRWS LOW CLOUDS SHOULD REMAIN TRAPPED BENEATH INVERSION
THROUGH TONIGHT... WITH DIMINISHING CLOUD TEND FRIDAY AS DRIER AIR
FILTERS IN.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

UPDATE...JT
SYNOPSIS...SKIPPER
SHORT TERM...SKIPPER
LONG TERM...LASHLEY
AVIATION...JT


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA








000
FXUS63 KIWX 181505
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1005 AM EST THU DEC 18 2014

.SYNOPSIS...
ISSUED AT 1240 AM EST THU DEC 18 2014

LIGHT LAKE EFFECT SNOW SHOWERS ARE POSSIBLE TODAY INTO THIS
EVENING AS A TROF MOVES SOUTH OVER LOWER MICHIGAN INTO NORTHERN
INDIANA. LITTLE IF ANY SNOW ACCUMULATION IS EXPECTED. HIGHS TODAY
AND FRIDAY WILL BE AROUND 30 TO 35. LOWS TONIGHT WILL BE IN THE
20S.

&&

.UPDATE...
ISSUED AT 950 AM EST THU DEC 18 2014

BAND OF LAKE EFFECT SNOW ASSOCIATED WITH SFC TROF MOVG SOUTH THROUGH
SRN MI/LM AND WK LAKE INDUCED INSTABILITY PASSED THROUGH MKG THIS
PAST HOUR WITH APPARENTLY SOME LIGHT ACCUM PER ASOS OB. THIS BAND IS
EXPECTED TO REMAIN NORTH OF OUR CWA THROUGH DAYLIGHT HOURS TODAY BUT
SHOULD REACH OUR SWRN MI COUNTIES EARLY THIS EVE. KEPT A CHC OF
PRECIP IN THE FCST ACROSS NRN PORTION OF THE CWA DUE TO WK LIFT
ASSOCIATED WITH WKNG UPR TROF MOVG EAST INTO THE OH VALLEY AND SOME
WK LAKE ENHANCEMENT. HWVR CHANGED PRECIP WORDING FOR THE DAYTIME
PERIOD TO FLURRIES/FREEZING DRIZZLE AS EXPECT A NON-MEASURABLE EVENT
THROUGH EARLY EVE AND MOISTURE ON MORNING DTX SOUNDING CONFINED TO
JUST BLO DGZ. GIVEN SFC TEMP-DWPT SPREADS AROUND 5F... DO NOT EXPECT
FREEZING DRIZZLE WILL BE HEAVY ENOUGH TO CAUSE GLAZED SURFACES...
JUST SOME SMALL LIQUID DROPLETS ON THE WINDSHIELD ALONG WITH THE
SNOW GRAINS.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 358 AM EST THU DEC 18 2014

UPPER AIR SOUNDINGS FROM YESTERDAY EVENING AND OVERNIGHT AIRCRAFT
OBSERVATIONS SHOWED AN INCREASING DEPTH TO THE INVERSION FROM
SOUTHWEST TO NORTHEAST. THE BASE OF THE INVERSION RANGED FROM LESS
THEN 2000 FEET AT LINCOLN IL/ILX...TO 4000 FEET AT FT WAYNE TO 5000
FEET NEAR DETROIT. OVERNIGHT SATELLITE SHOWED CLOUDS FILLING IN OVER
LAKE MICHIGAN WHERE THE INVERSION HEIGHT WAS ONLY 3000 FEET. THIS
LOW INVERSION HEIGHT WAS LIMITING LAKE EFFECT SNOW SHOWERS.  A
SURFACE TROF WILL MOVE SOUTH ACROSS LOWER MICHIGAN THIS AFTERNOON
AND INTO NORTHERN INDIANA THIS EVENING...AND HELP TO KEEP A SMALL
CHANCE FOR SNOW SHOWERS LATE TODAY AND EARLY TONIGHT. OTHERWISE...
KEPT LOW CHANCES FOR LIGHT LAKE EFFECT SNOW SHOWERS GIVEN A LOW
INVERSION HEIGHT AND A MARGINAL FETCH WITH MEAGER DELTA T VALUES
AROUND 11C. BELIEVE IT WILL BE DIFFICULT TO BREAK OUT OF THE LOW
CLOUDS WITH THIS PATTERN THROUGH TONIGHT. GIVEN ABUNDANT CLOUD
COVER...KEPT TEMPERATURES COLD TODAY WITH HIGHS ONLY IN THE LOWER
30S.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 358 AM EST THU DEC 18 2014

MOST IMPORTANT INFORMATION FIRST SO THIS LONG TERM WILL BEGIN WITH
DISCUSSION OF POSSIBLE WINTER STORM NEXT WEEK. HYPE ALREADY WELL
UNDERWAY BUT A LOT OF UNCERTAINTY REMAINS WITH RESPECT TO THE VERY
IMPORTANT AND CRITICAL DETAILS OF WHEN AND WHERE THIS STORM WILL
CREATE IMPACTS. CAUTIOUS BUT INFORMATIVE APPROACH WARRANTED GIVEN
THE DAY 6 TO 7 TIME FRAME AND A VERY ENERGETIC PACIFIC JET STREAM
WHICH IS POORLY SAMPLED. THUS NUMEROUS CRITICAL CHANGES AND
DEVIATIONS IN MODEL SOLUTIONS EXPECTED WITH EACH ITERATION OVER THE
NEXT SEVERAL DAYS. THE BROAD SYNOPTIC AGREEMENT AMONG MODELS DOES
GIVE HIGHER THAN NORMAL CONFIDENCE THAT A SUBSTANTIAL STORM SYSTEM WILL
IMPACT SOME PART OF THE EASTERN CONUS REGION BY CHRISTMAS.
HOWEVER...ALREADY SEEING MODEL ADJUSTMENTS IN POTENTIAL TIMING AND
TRACK OF SYSTEM AS WELL AS HOW FAST COLDER AIR WILL SWEEP IN.
CONFIDENCE REMAINS BELOW NORMAL ON IMPORTANT DETAILS SUCH AS
TRACK...PCPN TYPE AND AMOUNTS. LATEST 00Z MODELS TRENDING SYSTEM
WESTWARD AS THEY TEND TO DO WITH DYNAMICALLY STRONG AND NEGATIVELY
TILTED SYSTEMS. CURRENT MODEL RUNS DO BRING COLD AIR IN ON CHRISTMAS
EVE SO KEPT PCPN TYPE ALL SNOW IN THIS PERIOD FOR NOW. MODELS STILL
SHOWING A VERY STRONG LOW DEVELOPING WITH TIGHT GRADIENT AS BLOCKY
PATTERN STALLS SYSTEM OVER GREAT LAKES REGION. ANY SNOW THAT DOES
FALL BY CHRISTMAS WILL CERTAINLY CREATE TRAVEL ISSUES AND HAVE
SIGNIFICANT IMPACTS DUE TO BLOWING AND DRIFTING. THIS REMAINS WORTHY
OF MENTION IN HWO BUT RESTRAINT SHOULD BE EXERCISED FOR NOW IN THE
FORECASTS OF TRACK AND SNOW AMOUNTS GIVEN LITTLE SKILL AT THIS TIME
RANGE.

OTHERWISE A RATHER BENIGN LONG TERM PERIOD EXPECTED LEADING UP TO
THIS POTENTIAL STORM. SEASONABLE TEMPERATURES TO START THE PERIOD
FRIDAY WITH A SUBTLE WARMING TREND INTO EARLY NEXT WEEK. SEVERAL
WEAK SHORT WAVES AND TRAPPED LOW LEVEL MOISTURE BENEATH INVERSION TO
LIKELY KEEP SKIES AT LEAST PARTLY CLOUDY IF NOT MOSTLY CLOUDY
THROUGH THE PERIOD. INITIAL SHORT WAVE AND MOISTURE SURGE MONDAY
WILL BRING INITIAL CHANCES OF PCPN INTO THE REGION.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 558 AM EST THU DEC 18 2014

KEPT MVFR CIGS THE ENTIRE TAF PERIOD AT BOTH SBN AND FWA WITH
WEST WINDS 5-10 KTS. YESTERDAY EVENING UPPER AIR SOUNDINGS AND
OVERNIGHT AIRCRAFT OBSERVATIONS SHOW AN INCREASING DEPTH TO THE
FRONTAL INVERSION FROM SOUTHWEST TO NORTHEAST. AN AIRCRAFT
SOUNDING AT FWA LAST NIGHT SHOWED THE BASE OF THE SUBSIDENCE
INVERSION AROUND 850 MB...OR ABOUT 4000 FT ABOVE THE SFC. GIVEN
UPSTREAM MOISTURE BELOW THE INVERSION...A CONTINUED NORTHWEST TO
NORTH FETCH AND THE ADDITIONAL OF SOME LAKE MOISTURE...EXPECT IT
WILL BE DIFFICULT TO BREAK OUT OF THE MVFR SC DECK THIS TAF
PERIOD. THEREFORE... HAVE KEPT MVFR CIGS THE ENTIRE PERIOD.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR LMZ043-046.

&&

$$

UPDATE...JT
SYNOPSIS...SKIPPER
SHORT TERM...SKIPPER
LONG TERM...LASHLEY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA







000
FXUS63 KIWX 181505
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1005 AM EST THU DEC 18 2014

.SYNOPSIS...
ISSUED AT 1240 AM EST THU DEC 18 2014

LIGHT LAKE EFFECT SNOW SHOWERS ARE POSSIBLE TODAY INTO THIS
EVENING AS A TROF MOVES SOUTH OVER LOWER MICHIGAN INTO NORTHERN
INDIANA. LITTLE IF ANY SNOW ACCUMULATION IS EXPECTED. HIGHS TODAY
AND FRIDAY WILL BE AROUND 30 TO 35. LOWS TONIGHT WILL BE IN THE
20S.

&&

.UPDATE...
ISSUED AT 950 AM EST THU DEC 18 2014

BAND OF LAKE EFFECT SNOW ASSOCIATED WITH SFC TROF MOVG SOUTH THROUGH
SRN MI/LM AND WK LAKE INDUCED INSTABILITY PASSED THROUGH MKG THIS
PAST HOUR WITH APPARENTLY SOME LIGHT ACCUM PER ASOS OB. THIS BAND IS
EXPECTED TO REMAIN NORTH OF OUR CWA THROUGH DAYLIGHT HOURS TODAY BUT
SHOULD REACH OUR SWRN MI COUNTIES EARLY THIS EVE. KEPT A CHC OF
PRECIP IN THE FCST ACROSS NRN PORTION OF THE CWA DUE TO WK LIFT
ASSOCIATED WITH WKNG UPR TROF MOVG EAST INTO THE OH VALLEY AND SOME
WK LAKE ENHANCEMENT. HWVR CHANGED PRECIP WORDING FOR THE DAYTIME
PERIOD TO FLURRIES/FREEZING DRIZZLE AS EXPECT A NON-MEASURABLE EVENT
THROUGH EARLY EVE AND MOISTURE ON MORNING DTX SOUNDING CONFINED TO
JUST BLO DGZ. GIVEN SFC TEMP-DWPT SPREADS AROUND 5F... DO NOT EXPECT
FREEZING DRIZZLE WILL BE HEAVY ENOUGH TO CAUSE GLAZED SURFACES...
JUST SOME SMALL LIQUID DROPLETS ON THE WINDSHIELD ALONG WITH THE
SNOW GRAINS.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 358 AM EST THU DEC 18 2014

UPPER AIR SOUNDINGS FROM YESTERDAY EVENING AND OVERNIGHT AIRCRAFT
OBSERVATIONS SHOWED AN INCREASING DEPTH TO THE INVERSION FROM
SOUTHWEST TO NORTHEAST. THE BASE OF THE INVERSION RANGED FROM LESS
THEN 2000 FEET AT LINCOLN IL/ILX...TO 4000 FEET AT FT WAYNE TO 5000
FEET NEAR DETROIT. OVERNIGHT SATELLITE SHOWED CLOUDS FILLING IN OVER
LAKE MICHIGAN WHERE THE INVERSION HEIGHT WAS ONLY 3000 FEET. THIS
LOW INVERSION HEIGHT WAS LIMITING LAKE EFFECT SNOW SHOWERS.  A
SURFACE TROF WILL MOVE SOUTH ACROSS LOWER MICHIGAN THIS AFTERNOON
AND INTO NORTHERN INDIANA THIS EVENING...AND HELP TO KEEP A SMALL
CHANCE FOR SNOW SHOWERS LATE TODAY AND EARLY TONIGHT. OTHERWISE...
KEPT LOW CHANCES FOR LIGHT LAKE EFFECT SNOW SHOWERS GIVEN A LOW
INVERSION HEIGHT AND A MARGINAL FETCH WITH MEAGER DELTA T VALUES
AROUND 11C. BELIEVE IT WILL BE DIFFICULT TO BREAK OUT OF THE LOW
CLOUDS WITH THIS PATTERN THROUGH TONIGHT. GIVEN ABUNDANT CLOUD
COVER...KEPT TEMPERATURES COLD TODAY WITH HIGHS ONLY IN THE LOWER
30S.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 358 AM EST THU DEC 18 2014

MOST IMPORTANT INFORMATION FIRST SO THIS LONG TERM WILL BEGIN WITH
DISCUSSION OF POSSIBLE WINTER STORM NEXT WEEK. HYPE ALREADY WELL
UNDERWAY BUT A LOT OF UNCERTAINTY REMAINS WITH RESPECT TO THE VERY
IMPORTANT AND CRITICAL DETAILS OF WHEN AND WHERE THIS STORM WILL
CREATE IMPACTS. CAUTIOUS BUT INFORMATIVE APPROACH WARRANTED GIVEN
THE DAY 6 TO 7 TIME FRAME AND A VERY ENERGETIC PACIFIC JET STREAM
WHICH IS POORLY SAMPLED. THUS NUMEROUS CRITICAL CHANGES AND
DEVIATIONS IN MODEL SOLUTIONS EXPECTED WITH EACH ITERATION OVER THE
NEXT SEVERAL DAYS. THE BROAD SYNOPTIC AGREEMENT AMONG MODELS DOES
GIVE HIGHER THAN NORMAL CONFIDENCE THAT A SUBSTANTIAL STORM SYSTEM WILL
IMPACT SOME PART OF THE EASTERN CONUS REGION BY CHRISTMAS.
HOWEVER...ALREADY SEEING MODEL ADJUSTMENTS IN POTENTIAL TIMING AND
TRACK OF SYSTEM AS WELL AS HOW FAST COLDER AIR WILL SWEEP IN.
CONFIDENCE REMAINS BELOW NORMAL ON IMPORTANT DETAILS SUCH AS
TRACK...PCPN TYPE AND AMOUNTS. LATEST 00Z MODELS TRENDING SYSTEM
WESTWARD AS THEY TEND TO DO WITH DYNAMICALLY STRONG AND NEGATIVELY
TILTED SYSTEMS. CURRENT MODEL RUNS DO BRING COLD AIR IN ON CHRISTMAS
EVE SO KEPT PCPN TYPE ALL SNOW IN THIS PERIOD FOR NOW. MODELS STILL
SHOWING A VERY STRONG LOW DEVELOPING WITH TIGHT GRADIENT AS BLOCKY
PATTERN STALLS SYSTEM OVER GREAT LAKES REGION. ANY SNOW THAT DOES
FALL BY CHRISTMAS WILL CERTAINLY CREATE TRAVEL ISSUES AND HAVE
SIGNIFICANT IMPACTS DUE TO BLOWING AND DRIFTING. THIS REMAINS WORTHY
OF MENTION IN HWO BUT RESTRAINT SHOULD BE EXERCISED FOR NOW IN THE
FORECASTS OF TRACK AND SNOW AMOUNTS GIVEN LITTLE SKILL AT THIS TIME
RANGE.

OTHERWISE A RATHER BENIGN LONG TERM PERIOD EXPECTED LEADING UP TO
THIS POTENTIAL STORM. SEASONABLE TEMPERATURES TO START THE PERIOD
FRIDAY WITH A SUBTLE WARMING TREND INTO EARLY NEXT WEEK. SEVERAL
WEAK SHORT WAVES AND TRAPPED LOW LEVEL MOISTURE BENEATH INVERSION TO
LIKELY KEEP SKIES AT LEAST PARTLY CLOUDY IF NOT MOSTLY CLOUDY
THROUGH THE PERIOD. INITIAL SHORT WAVE AND MOISTURE SURGE MONDAY
WILL BRING INITIAL CHANCES OF PCPN INTO THE REGION.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 558 AM EST THU DEC 18 2014

KEPT MVFR CIGS THE ENTIRE TAF PERIOD AT BOTH SBN AND FWA WITH
WEST WINDS 5-10 KTS. YESTERDAY EVENING UPPER AIR SOUNDINGS AND
OVERNIGHT AIRCRAFT OBSERVATIONS SHOW AN INCREASING DEPTH TO THE
FRONTAL INVERSION FROM SOUTHWEST TO NORTHEAST. AN AIRCRAFT
SOUNDING AT FWA LAST NIGHT SHOWED THE BASE OF THE SUBSIDENCE
INVERSION AROUND 850 MB...OR ABOUT 4000 FT ABOVE THE SFC. GIVEN
UPSTREAM MOISTURE BELOW THE INVERSION...A CONTINUED NORTHWEST TO
NORTH FETCH AND THE ADDITIONAL OF SOME LAKE MOISTURE...EXPECT IT
WILL BE DIFFICULT TO BREAK OUT OF THE MVFR SC DECK THIS TAF
PERIOD. THEREFORE... HAVE KEPT MVFR CIGS THE ENTIRE PERIOD.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR LMZ043-046.

&&

$$

UPDATE...JT
SYNOPSIS...SKIPPER
SHORT TERM...SKIPPER
LONG TERM...LASHLEY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA








000
FXUS63 KIWX 181103
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
603 AM EST THU DEC 18 2014

.SYNOPSIS...
ISSUED AT 1240 AM EST THU DEC 18 2014

LIGHT LAKE EFFECT SNOW SHOWERS ARE POSSIBLE TODAY INTO THIS
EVENING AS A TROF MOVES SOUTH OVER LOWER MICHIGAN INTO NORTHERN
INDIANA. LITTLE IF ANY SNOW ACCUMULATION IS EXPECTED. HIGHS TODAY
AND FRIDAY WILL BE AROUND 30 TO 35. LOWS TONIGHT WILL BE IN THE
20S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 358 AM EST THU DEC 18 2014

UPPER AIR SOUNDINGS FROM YESTERDAY EVENING AND OVERNIGHT AIRCRAFT
OBSERVATIONS SHOWED AN INCREASING DEPTH TO THE INVERSION FROM
SOUTHWEST TO NORTHEAST. THE BASE OF THE INVERSION RANGED FROM LESS
THEN 2000 FEET AT LINCOLN IL/ILX...TO 4000 FEET AT FT WAYNE TO 5000
FEET NEAR DETROIT. OVERNIGHT SATELLITE SHOWED CLOUDS FILLING IN OVER
LAKE MICHIGAN WHERE THE INVERSION HEIGHT WAS ONLY 3000 FEET. THIS
LOW INVERSION HEIGHT WAS LIMITING LAKE EFFECT SNOW SHOWERS.  A
SURFACE TROF WILL MOVE SOUTH ACROSS LOWER MICHIGAN THIS AFTERNOON
AND INTO NORTHERN INDIANA THIS EVENING...AND HELP TO KEEP A SMALL
CHANCE FOR SNOW SHOWERS LATE TODAY AND EARLY TONIGHT. OTHERWISE...
KEPT LOW CHANCES FOR LIGHT LAKE EFFECT SNOW SHOWERS GIVEN A LOW
INVERSION HEIGHT AND A MARGINAL FETCH WITH MEAGER DELTA T VALUES
AROUND 11C. BELIEVE IT WILL BE DIFFICULT TO BREAK OUT OF THE LOW
CLOUDS WITH THIS PATTERN THROUGH TONIGHT. GIVEN ABUNDANT CLOUD
COVER...KEPT TEMPERATURES COLD TODAY WITH HIGHS ONLY IN THE LOWER
30S.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 358 AM EST THU DEC 18 2014

MOST IMPORTANT INFORMATION FIRST SO THIS LONG TERM WILL BEGIN WITH
DISCUSSION OF POSSIBLE WINTER STORM NEXT WEEK. HYPE ALREADY WELL
UNDERWAY BUT A LOT OF UNCERTAINTY REMAINS WITH RESPECT TO THE VERY
IMPORTANT AND CRITICAL DETAILS OF WHEN AND WHERE THIS STORM WILL
CREATE IMPACTS. CAUTIOUS BUT INFORMATIVE APPROACH WARRANTED GIVEN
THE DAY 6 TO 7 TIME FRAME AND A VERY ENERGETIC PACIFIC JET STREAM
WHICH IS POORLY SAMPLED. THUS NUMEROUS CRITICAL CHANGES AND
DEVIATIONS IN MODEL SOLUTIONS EXPECTED WITH EACH ITERATION OVER THE
NEXT SEVERAL DAYS. THE BROAD SYNOPTIC AGREEMENT AMONG MODELS DOES
GIVE HIGHER THAN NORMAL CONFIDENCE THAT A SUBSTANTIAL STORM SYSTEM WILL
IMPACT SOME PART OF THE EASTERN CONUS REGION BY CHRISTMAS.
HOWEVER...ALREADY SEEING MODEL ADJUSTMENTS IN POTENTIAL TIMING AND
TRACK OF SYSTEM AS WELL AS HOW FAST COLDER AIR WILL SWEEP IN.
CONFIDENCE REMAINS BELOW NORMAL ON IMPORTANT DETAILS SUCH AS
TRACK...PCPN TYPE AND AMOUNTS. LATEST 00Z MODELS TRENDING SYSTEM
WESTWARD AS THEY TEND TO DO WITH DYNAMICALLY STRONG AND NEGATIVELY
TILTED SYSTEMS. CURRENT MODEL RUNS DO BRING COLD AIR IN ON CHRISTMAS
EVE SO KEPT PCPN TYPE ALL SNOW IN THIS PERIOD FOR NOW. MODELS STILL
SHOWING A VERY STRONG LOW DEVELOPING WITH TIGHT GRADIENT AS BLOCKY
PATTERN STALLS SYSTEM OVER GREAT LAKES REGION. ANY SNOW THAT DOES
FALL BY CHRISTMAS WILL CERTAINLY CREATE TRAVEL ISSUES AND HAVE
SIGNIFICANT IMPACTS DUE TO BLOWING AND DRIFTING. THIS REMAINS WORTHY
OF MENTION IN HWO BUT RESTRAINT SHOULD BE EXERCISED FOR NOW IN THE
FORECASTS OF TRACK AND SNOW AMOUNTS GIVEN LITTLE SKILL AT THIS TIME
RANGE.

OTHERWISE A RATHER BENIGN LONG TERM PERIOD EXPECTED LEADING UP TO
THIS POTENTIAL STORM. SEASONABLE TEMPERATURES TO START THE PERIOD
FRIDAY WITH A SUBTLE WARMING TREND INTO EARLY NEXT WEEK. SEVERAL
WEAK SHORT WAVES AND TRAPPED LOW LEVEL MOISTURE BENEATH INVERSION TO
LIKELY KEEP SKIES AT LEAST PARTLY CLOUDY IF NOT MOSTLY CLOUDY
THROUGH THE PERIOD. INITIAL SHORT WAVE AND MOISTURE SURGE MONDAY
WILL BRING INITIAL CHANCES OF PCPN INTO THE REGION.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 558 AM EST THU DEC 18 2014

KEPT MVFR CIGS THE ENTIRE TAF PERIOD AT BOTH SBN AND FWA WITH
WEST WINDS 5-10 KTS. YESTERDAY EVENING UPPER AIR SOUNDINGS AND
OVERNIGHT AIRCRAFT OBSERVATIONS SHOW AN INCREASING DEPTH TO THE
FRONTAL INVERSION FROM SOUTHWEST TO NORTHEAST. AN AIRCRAFT
SOUNDING AT FWA LAST NIGHT SHOWED THE BASE OF THE SUBSIDENCE
INVERSION AROUND 850 MB...OR ABOUT 4000 FT ABOVE THE SFC. GIVEN
UPSTREAM MOISTURE BELOW THE INVERSION...A CONTINUED NORTHWEST TO
NORTH FETCH AND THE ADDITIONAL OF SOME LAKE MOISTURE...EXPECT IT
WILL BE DIFFICULT TO BREAK OUT OF THE MVFR SC DECK THIS TAF
PERIOD. THEREFORE... HAVE KEPT MVFR CIGS THE ENTIRE PERIOD.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR LMZ043-046.

&&

$$

SYNOPSIS...SKIPPER
SHORT TERM...SKIPPER
LONG TERM...LASHLEY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA









000
FXUS63 KIWX 181103
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
603 AM EST THU DEC 18 2014

.SYNOPSIS...
ISSUED AT 1240 AM EST THU DEC 18 2014

LIGHT LAKE EFFECT SNOW SHOWERS ARE POSSIBLE TODAY INTO THIS
EVENING AS A TROF MOVES SOUTH OVER LOWER MICHIGAN INTO NORTHERN
INDIANA. LITTLE IF ANY SNOW ACCUMULATION IS EXPECTED. HIGHS TODAY
AND FRIDAY WILL BE AROUND 30 TO 35. LOWS TONIGHT WILL BE IN THE
20S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 358 AM EST THU DEC 18 2014

UPPER AIR SOUNDINGS FROM YESTERDAY EVENING AND OVERNIGHT AIRCRAFT
OBSERVATIONS SHOWED AN INCREASING DEPTH TO THE INVERSION FROM
SOUTHWEST TO NORTHEAST. THE BASE OF THE INVERSION RANGED FROM LESS
THEN 2000 FEET AT LINCOLN IL/ILX...TO 4000 FEET AT FT WAYNE TO 5000
FEET NEAR DETROIT. OVERNIGHT SATELLITE SHOWED CLOUDS FILLING IN OVER
LAKE MICHIGAN WHERE THE INVERSION HEIGHT WAS ONLY 3000 FEET. THIS
LOW INVERSION HEIGHT WAS LIMITING LAKE EFFECT SNOW SHOWERS.  A
SURFACE TROF WILL MOVE SOUTH ACROSS LOWER MICHIGAN THIS AFTERNOON
AND INTO NORTHERN INDIANA THIS EVENING...AND HELP TO KEEP A SMALL
CHANCE FOR SNOW SHOWERS LATE TODAY AND EARLY TONIGHT. OTHERWISE...
KEPT LOW CHANCES FOR LIGHT LAKE EFFECT SNOW SHOWERS GIVEN A LOW
INVERSION HEIGHT AND A MARGINAL FETCH WITH MEAGER DELTA T VALUES
AROUND 11C. BELIEVE IT WILL BE DIFFICULT TO BREAK OUT OF THE LOW
CLOUDS WITH THIS PATTERN THROUGH TONIGHT. GIVEN ABUNDANT CLOUD
COVER...KEPT TEMPERATURES COLD TODAY WITH HIGHS ONLY IN THE LOWER
30S.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 358 AM EST THU DEC 18 2014

MOST IMPORTANT INFORMATION FIRST SO THIS LONG TERM WILL BEGIN WITH
DISCUSSION OF POSSIBLE WINTER STORM NEXT WEEK. HYPE ALREADY WELL
UNDERWAY BUT A LOT OF UNCERTAINTY REMAINS WITH RESPECT TO THE VERY
IMPORTANT AND CRITICAL DETAILS OF WHEN AND WHERE THIS STORM WILL
CREATE IMPACTS. CAUTIOUS BUT INFORMATIVE APPROACH WARRANTED GIVEN
THE DAY 6 TO 7 TIME FRAME AND A VERY ENERGETIC PACIFIC JET STREAM
WHICH IS POORLY SAMPLED. THUS NUMEROUS CRITICAL CHANGES AND
DEVIATIONS IN MODEL SOLUTIONS EXPECTED WITH EACH ITERATION OVER THE
NEXT SEVERAL DAYS. THE BROAD SYNOPTIC AGREEMENT AMONG MODELS DOES
GIVE HIGHER THAN NORMAL CONFIDENCE THAT A SUBSTANTIAL STORM SYSTEM WILL
IMPACT SOME PART OF THE EASTERN CONUS REGION BY CHRISTMAS.
HOWEVER...ALREADY SEEING MODEL ADJUSTMENTS IN POTENTIAL TIMING AND
TRACK OF SYSTEM AS WELL AS HOW FAST COLDER AIR WILL SWEEP IN.
CONFIDENCE REMAINS BELOW NORMAL ON IMPORTANT DETAILS SUCH AS
TRACK...PCPN TYPE AND AMOUNTS. LATEST 00Z MODELS TRENDING SYSTEM
WESTWARD AS THEY TEND TO DO WITH DYNAMICALLY STRONG AND NEGATIVELY
TILTED SYSTEMS. CURRENT MODEL RUNS DO BRING COLD AIR IN ON CHRISTMAS
EVE SO KEPT PCPN TYPE ALL SNOW IN THIS PERIOD FOR NOW. MODELS STILL
SHOWING A VERY STRONG LOW DEVELOPING WITH TIGHT GRADIENT AS BLOCKY
PATTERN STALLS SYSTEM OVER GREAT LAKES REGION. ANY SNOW THAT DOES
FALL BY CHRISTMAS WILL CERTAINLY CREATE TRAVEL ISSUES AND HAVE
SIGNIFICANT IMPACTS DUE TO BLOWING AND DRIFTING. THIS REMAINS WORTHY
OF MENTION IN HWO BUT RESTRAINT SHOULD BE EXERCISED FOR NOW IN THE
FORECASTS OF TRACK AND SNOW AMOUNTS GIVEN LITTLE SKILL AT THIS TIME
RANGE.

OTHERWISE A RATHER BENIGN LONG TERM PERIOD EXPECTED LEADING UP TO
THIS POTENTIAL STORM. SEASONABLE TEMPERATURES TO START THE PERIOD
FRIDAY WITH A SUBTLE WARMING TREND INTO EARLY NEXT WEEK. SEVERAL
WEAK SHORT WAVES AND TRAPPED LOW LEVEL MOISTURE BENEATH INVERSION TO
LIKELY KEEP SKIES AT LEAST PARTLY CLOUDY IF NOT MOSTLY CLOUDY
THROUGH THE PERIOD. INITIAL SHORT WAVE AND MOISTURE SURGE MONDAY
WILL BRING INITIAL CHANCES OF PCPN INTO THE REGION.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 558 AM EST THU DEC 18 2014

KEPT MVFR CIGS THE ENTIRE TAF PERIOD AT BOTH SBN AND FWA WITH
WEST WINDS 5-10 KTS. YESTERDAY EVENING UPPER AIR SOUNDINGS AND
OVERNIGHT AIRCRAFT OBSERVATIONS SHOW AN INCREASING DEPTH TO THE
FRONTAL INVERSION FROM SOUTHWEST TO NORTHEAST. AN AIRCRAFT
SOUNDING AT FWA LAST NIGHT SHOWED THE BASE OF THE SUBSIDENCE
INVERSION AROUND 850 MB...OR ABOUT 4000 FT ABOVE THE SFC. GIVEN
UPSTREAM MOISTURE BELOW THE INVERSION...A CONTINUED NORTHWEST TO
NORTH FETCH AND THE ADDITIONAL OF SOME LAKE MOISTURE...EXPECT IT
WILL BE DIFFICULT TO BREAK OUT OF THE MVFR SC DECK THIS TAF
PERIOD. THEREFORE... HAVE KEPT MVFR CIGS THE ENTIRE PERIOD.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR LMZ043-046.

&&

$$

SYNOPSIS...SKIPPER
SHORT TERM...SKIPPER
LONG TERM...LASHLEY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA








000
FXUS63 KIWX 181103
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
603 AM EST THU DEC 18 2014

.SYNOPSIS...
ISSUED AT 1240 AM EST THU DEC 18 2014

LIGHT LAKE EFFECT SNOW SHOWERS ARE POSSIBLE TODAY INTO THIS
EVENING AS A TROF MOVES SOUTH OVER LOWER MICHIGAN INTO NORTHERN
INDIANA. LITTLE IF ANY SNOW ACCUMULATION IS EXPECTED. HIGHS TODAY
AND FRIDAY WILL BE AROUND 30 TO 35. LOWS TONIGHT WILL BE IN THE
20S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 358 AM EST THU DEC 18 2014

UPPER AIR SOUNDINGS FROM YESTERDAY EVENING AND OVERNIGHT AIRCRAFT
OBSERVATIONS SHOWED AN INCREASING DEPTH TO THE INVERSION FROM
SOUTHWEST TO NORTHEAST. THE BASE OF THE INVERSION RANGED FROM LESS
THEN 2000 FEET AT LINCOLN IL/ILX...TO 4000 FEET AT FT WAYNE TO 5000
FEET NEAR DETROIT. OVERNIGHT SATELLITE SHOWED CLOUDS FILLING IN OVER
LAKE MICHIGAN WHERE THE INVERSION HEIGHT WAS ONLY 3000 FEET. THIS
LOW INVERSION HEIGHT WAS LIMITING LAKE EFFECT SNOW SHOWERS.  A
SURFACE TROF WILL MOVE SOUTH ACROSS LOWER MICHIGAN THIS AFTERNOON
AND INTO NORTHERN INDIANA THIS EVENING...AND HELP TO KEEP A SMALL
CHANCE FOR SNOW SHOWERS LATE TODAY AND EARLY TONIGHT. OTHERWISE...
KEPT LOW CHANCES FOR LIGHT LAKE EFFECT SNOW SHOWERS GIVEN A LOW
INVERSION HEIGHT AND A MARGINAL FETCH WITH MEAGER DELTA T VALUES
AROUND 11C. BELIEVE IT WILL BE DIFFICULT TO BREAK OUT OF THE LOW
CLOUDS WITH THIS PATTERN THROUGH TONIGHT. GIVEN ABUNDANT CLOUD
COVER...KEPT TEMPERATURES COLD TODAY WITH HIGHS ONLY IN THE LOWER
30S.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 358 AM EST THU DEC 18 2014

MOST IMPORTANT INFORMATION FIRST SO THIS LONG TERM WILL BEGIN WITH
DISCUSSION OF POSSIBLE WINTER STORM NEXT WEEK. HYPE ALREADY WELL
UNDERWAY BUT A LOT OF UNCERTAINTY REMAINS WITH RESPECT TO THE VERY
IMPORTANT AND CRITICAL DETAILS OF WHEN AND WHERE THIS STORM WILL
CREATE IMPACTS. CAUTIOUS BUT INFORMATIVE APPROACH WARRANTED GIVEN
THE DAY 6 TO 7 TIME FRAME AND A VERY ENERGETIC PACIFIC JET STREAM
WHICH IS POORLY SAMPLED. THUS NUMEROUS CRITICAL CHANGES AND
DEVIATIONS IN MODEL SOLUTIONS EXPECTED WITH EACH ITERATION OVER THE
NEXT SEVERAL DAYS. THE BROAD SYNOPTIC AGREEMENT AMONG MODELS DOES
GIVE HIGHER THAN NORMAL CONFIDENCE THAT A SUBSTANTIAL STORM SYSTEM WILL
IMPACT SOME PART OF THE EASTERN CONUS REGION BY CHRISTMAS.
HOWEVER...ALREADY SEEING MODEL ADJUSTMENTS IN POTENTIAL TIMING AND
TRACK OF SYSTEM AS WELL AS HOW FAST COLDER AIR WILL SWEEP IN.
CONFIDENCE REMAINS BELOW NORMAL ON IMPORTANT DETAILS SUCH AS
TRACK...PCPN TYPE AND AMOUNTS. LATEST 00Z MODELS TRENDING SYSTEM
WESTWARD AS THEY TEND TO DO WITH DYNAMICALLY STRONG AND NEGATIVELY
TILTED SYSTEMS. CURRENT MODEL RUNS DO BRING COLD AIR IN ON CHRISTMAS
EVE SO KEPT PCPN TYPE ALL SNOW IN THIS PERIOD FOR NOW. MODELS STILL
SHOWING A VERY STRONG LOW DEVELOPING WITH TIGHT GRADIENT AS BLOCKY
PATTERN STALLS SYSTEM OVER GREAT LAKES REGION. ANY SNOW THAT DOES
FALL BY CHRISTMAS WILL CERTAINLY CREATE TRAVEL ISSUES AND HAVE
SIGNIFICANT IMPACTS DUE TO BLOWING AND DRIFTING. THIS REMAINS WORTHY
OF MENTION IN HWO BUT RESTRAINT SHOULD BE EXERCISED FOR NOW IN THE
FORECASTS OF TRACK AND SNOW AMOUNTS GIVEN LITTLE SKILL AT THIS TIME
RANGE.

OTHERWISE A RATHER BENIGN LONG TERM PERIOD EXPECTED LEADING UP TO
THIS POTENTIAL STORM. SEASONABLE TEMPERATURES TO START THE PERIOD
FRIDAY WITH A SUBTLE WARMING TREND INTO EARLY NEXT WEEK. SEVERAL
WEAK SHORT WAVES AND TRAPPED LOW LEVEL MOISTURE BENEATH INVERSION TO
LIKELY KEEP SKIES AT LEAST PARTLY CLOUDY IF NOT MOSTLY CLOUDY
THROUGH THE PERIOD. INITIAL SHORT WAVE AND MOISTURE SURGE MONDAY
WILL BRING INITIAL CHANCES OF PCPN INTO THE REGION.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 558 AM EST THU DEC 18 2014

KEPT MVFR CIGS THE ENTIRE TAF PERIOD AT BOTH SBN AND FWA WITH
WEST WINDS 5-10 KTS. YESTERDAY EVENING UPPER AIR SOUNDINGS AND
OVERNIGHT AIRCRAFT OBSERVATIONS SHOW AN INCREASING DEPTH TO THE
FRONTAL INVERSION FROM SOUTHWEST TO NORTHEAST. AN AIRCRAFT
SOUNDING AT FWA LAST NIGHT SHOWED THE BASE OF THE SUBSIDENCE
INVERSION AROUND 850 MB...OR ABOUT 4000 FT ABOVE THE SFC. GIVEN
UPSTREAM MOISTURE BELOW THE INVERSION...A CONTINUED NORTHWEST TO
NORTH FETCH AND THE ADDITIONAL OF SOME LAKE MOISTURE...EXPECT IT
WILL BE DIFFICULT TO BREAK OUT OF THE MVFR SC DECK THIS TAF
PERIOD. THEREFORE... HAVE KEPT MVFR CIGS THE ENTIRE PERIOD.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR LMZ043-046.

&&

$$

SYNOPSIS...SKIPPER
SHORT TERM...SKIPPER
LONG TERM...LASHLEY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA









000
FXUS63 KIWX 180900
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
400 AM EST THU DEC 18 2014

.SYNOPSIS...
ISSUED AT 1240 AM EST THU DEC 18 2014

LIGHT LAKE EFFECT SNOW SHOWERS ARE POSSIBLE TODAY AS A TROF MOVES
SOUTH OVER LOWER MICHIGAN INTO NORTHERN INDIANA. THE WINDS BEHIND
THIS TROF WILL MAKE THE FETCH A LITTLE MORE FAVORABLE FOR LAKE
EFFECT SNOW. HOWEVER...LITTLE IF ANY SNOW ACCUMULATION IS
EXPECTED. HIGHS TODAY AND FRIDAY WILL BE AROUND 30 TO 35. LOWS
TONIGHT WILL BE IN THE 20S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 358 AM EST THU DEC 18 2014

UPPER AIR SOUNDINGS FROM YESTERDAY EVENING AND OVERNIGHT AIRCRAFT
OBSERVATIONS SHOWED AN INCREASING DEPTH TO THE INVERSION FROM
SOUTHWEST TO NORTHEAST. THE BASE OF THE INVERSION RANGED FROM LESS
THEN 2000 FEET AT LINCOLN IL/ILX...TO 4000 FEET AT FT WAYNE TO 5000
FEET NEAR DETROIT. OVERNIGHT SATELLITE SHOWED CLOUDS FILLING IN OVER
LAKE MICHIGAN WHERE THE INVERSION HEIGHT WAS ONLY 3000 FEET. THIS
LOW INVERSION HEIGHT WAS LIMITING LAKE EFFECT SNOW SHOWERS.  A
SURFACE TROF WILL MOVE SOUTH ACROSS LOWER MICHIGAN THIS AFTERNOON
AND INTO NORTHERN INDIANA THIS EVENING...AND HELP TO KEEP A SMALL
CHANCE FOR SNOW SHOWERS LATE TODAY AND EARLY TONIGHT. OTHERWISE...
KEPT LOW CHANCES FOR LIGHT LAKE EFFECT SNOW SHOWERS GIVEN A LOW
INVERSION HEIGHT AND A MARGINAL FETCH WITH MEAGER DELTA T VALUES
AROUND 11C. BELIEVE IT WILL BE DIFFICULT TO BREAK OUT OF THE LOW
CLOUDS WITH THIS PATTERN THROUGH TONIGHT. GIVEN ABUNDANT CLOUD
COVER...KEPT TEMPERATURES COLD TODAY WITH HIGHS ONLY IN THE LOWER
30S.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 358 AM EST THU DEC 18 2014


MOST IMPORTANT INFORMATION FIRST SO THIS LONG TERM WILL BEGIN WITH
DISCUSSION OF POSSIBLE WINTER STORM NEXT WEEK. HYPE ALREADY WELL
UNDERWAY BUT A LOT OF UNCERTAINTY REMAINS WITH RESPECT TO THE VERY
IMPORTANT AND CRITICAL DETAILS OF WHEN AND WHERE THIS STORM WILL
CREATE IMPACTS. CAUTIOUS BUT INFORMATIVE APPROACH WARRANTED GIVEN
THE DAY 6 TO 7 TIME FRAME AND A VERY ENERGETIC PACIFIC JET STREAM
WHICH IS POORLY SAMPLED. THUS NUMEROUS CRITICAL CHANGES AND
DEVIATIONS IN MODEL SOLUTIONS EXPECTED WITH EACH ITERATION OVER THE
NEXT SEVERAL DAYS. THE BROAD SYNOPTIC AGREEMENT AMONG MODELS DOES
GIVE HIGHER THAN NORMAL CONFIDENCE THAT A SUBSTANTIAL STORM SYSTEM WILL
IMPACT SOME PART OF THE EASTERN CONUS REGION BY CHRISTMAS.
HOWEVER...ALREADY SEEING MODEL ADJUSTMENTS IN POTENTIAL TIMING AND
TRACK OF SYSTEM AS WELL AS HOW FAST COLDER AIR WILL SWEEP IN.
CONFIDENCE REMAINS BELOW NORMAL ON IMPORTANT DETAILS SUCH AS
TRACK...PCPN TYPE AND AMOUNTS. LATEST 00Z MODELS TRENDING SYSTEM
WESTWARD AS THEY TEND TO DO WITH DYNAMICALLY STRONG AND NEGATIVELY
TILTED SYSTEMS. CURRENT MODEL RUNS DO BRING COLD AIR IN ON CHRISTMAS
EVE SO KEPT PCPN TYPE ALL SNOW IN THIS PERIOD FOR NOW. MODELS STILL
SHOWING A VERY STRONG LOW DEVELOPING WITH TIGHT GRADIENT AS BLOCKY
PATTERN STALLS SYSTEM OVER GREAT LAKES REGION. ANY SNOW THAT DOES
FALL BY CHRISTMAS WILL CERTAINLY CREATE TRAVEL ISSUES AND HAVE
SIGNIFICANT IMPACTS DUE TO BLOWING AND DRIFTING. THIS REMAINS WORTHY
OF MENTION IN HWO BUT RESTRAINT SHOULD BE EXERCISED FOR NOW IN THE
FORECASTS OF TRACK AND SNOW AMOUNTS GIVEN LITTLE SKILL AT THIS TIME
RANGE.

OTHERWISE A RATHER BENIGN LONG TERM PERIOD EXPECTED LEADING UP TO
THIS POTENTIAL STORM. SEASONABLE TEMPERATURES TO START THE PERIOD
FRIDAY WITH A SUBTLE WARMING TREND INTO EARLY NEXT WEEK. SEVERAL
WEAK SHORT WAVES AND TRAPPED LOW LEVEL MOISTURE BENEATH INVERSION TO
LIKELY KEEP SKIES AT LEAST PARTLY CLOUDY IF NOT MOSTLY CLOUDY
THROUGH THE PERIOD. INITIAL SHORT WAVE AND MOISTURE SURGE MONDAY
WILL BRING INITIAL CHANCES OF PCPN INTO THE REGION.


&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1209 AM EST THU DEC 18 2014

KEPT MVFR CIGS THE ENTIRE TAF PERIOD AT BOTH SBN AND FWA WITH WEST
WINDS 7-10 KTS. EARLY EVENING UPPER AIR SOUNDINGS AND OVERNIGHT
AIRCRAFT OBSERVATIONS SHOW AN INCREASING DEPTH TO THE FRONTAL
INVERSION FROM SOUTHWEST TO NORTHEAST. AN AIRCRAFT SOUNDING AT FWA
AT 0316Z SHOWED THE BASE OF THE SUBSIDENCE INVERSION AROUND 850
MB...OR ABOUT 4000 FT ABOVE THE SFC. GIVEN UPSTREAM MOISTURE BELOW
THE INVERSION...A CONTINUED NORTHWEST TO NORTH FETCH AND THE
ADDITIONAL OF SOME LAKE MOISTURE...BELIEVE IT WILL BE DIFFICULT TO
BREAK OUT OF THE MVFR SC DECK FOR THE NEXT 24 HOURS. THEREFORE...
HAVE KEPT MVFR CIGS THE ENTIRE PERIOD.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR LMZ043-046.

&&

$$

SYNOPSIS...SKIPPER
SHORT TERM...SKIPPER
LONG TERM...LASHLEY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA







000
FXUS63 KIWX 180900
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
400 AM EST THU DEC 18 2014

.SYNOPSIS...
ISSUED AT 1240 AM EST THU DEC 18 2014

LIGHT LAKE EFFECT SNOW SHOWERS ARE POSSIBLE TODAY AS A TROF MOVES
SOUTH OVER LOWER MICHIGAN INTO NORTHERN INDIANA. THE WINDS BEHIND
THIS TROF WILL MAKE THE FETCH A LITTLE MORE FAVORABLE FOR LAKE
EFFECT SNOW. HOWEVER...LITTLE IF ANY SNOW ACCUMULATION IS
EXPECTED. HIGHS TODAY AND FRIDAY WILL BE AROUND 30 TO 35. LOWS
TONIGHT WILL BE IN THE 20S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 358 AM EST THU DEC 18 2014

UPPER AIR SOUNDINGS FROM YESTERDAY EVENING AND OVERNIGHT AIRCRAFT
OBSERVATIONS SHOWED AN INCREASING DEPTH TO THE INVERSION FROM
SOUTHWEST TO NORTHEAST. THE BASE OF THE INVERSION RANGED FROM LESS
THEN 2000 FEET AT LINCOLN IL/ILX...TO 4000 FEET AT FT WAYNE TO 5000
FEET NEAR DETROIT. OVERNIGHT SATELLITE SHOWED CLOUDS FILLING IN OVER
LAKE MICHIGAN WHERE THE INVERSION HEIGHT WAS ONLY 3000 FEET. THIS
LOW INVERSION HEIGHT WAS LIMITING LAKE EFFECT SNOW SHOWERS.  A
SURFACE TROF WILL MOVE SOUTH ACROSS LOWER MICHIGAN THIS AFTERNOON
AND INTO NORTHERN INDIANA THIS EVENING...AND HELP TO KEEP A SMALL
CHANCE FOR SNOW SHOWERS LATE TODAY AND EARLY TONIGHT. OTHERWISE...
KEPT LOW CHANCES FOR LIGHT LAKE EFFECT SNOW SHOWERS GIVEN A LOW
INVERSION HEIGHT AND A MARGINAL FETCH WITH MEAGER DELTA T VALUES
AROUND 11C. BELIEVE IT WILL BE DIFFICULT TO BREAK OUT OF THE LOW
CLOUDS WITH THIS PATTERN THROUGH TONIGHT. GIVEN ABUNDANT CLOUD
COVER...KEPT TEMPERATURES COLD TODAY WITH HIGHS ONLY IN THE LOWER
30S.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 358 AM EST THU DEC 18 2014


MOST IMPORTANT INFORMATION FIRST SO THIS LONG TERM WILL BEGIN WITH
DISCUSSION OF POSSIBLE WINTER STORM NEXT WEEK. HYPE ALREADY WELL
UNDERWAY BUT A LOT OF UNCERTAINTY REMAINS WITH RESPECT TO THE VERY
IMPORTANT AND CRITICAL DETAILS OF WHEN AND WHERE THIS STORM WILL
CREATE IMPACTS. CAUTIOUS BUT INFORMATIVE APPROACH WARRANTED GIVEN
THE DAY 6 TO 7 TIME FRAME AND A VERY ENERGETIC PACIFIC JET STREAM
WHICH IS POORLY SAMPLED. THUS NUMEROUS CRITICAL CHANGES AND
DEVIATIONS IN MODEL SOLUTIONS EXPECTED WITH EACH ITERATION OVER THE
NEXT SEVERAL DAYS. THE BROAD SYNOPTIC AGREEMENT AMONG MODELS DOES
GIVE HIGHER THAN NORMAL CONFIDENCE THAT A SUBSTANTIAL STORM SYSTEM WILL
IMPACT SOME PART OF THE EASTERN CONUS REGION BY CHRISTMAS.
HOWEVER...ALREADY SEEING MODEL ADJUSTMENTS IN POTENTIAL TIMING AND
TRACK OF SYSTEM AS WELL AS HOW FAST COLDER AIR WILL SWEEP IN.
CONFIDENCE REMAINS BELOW NORMAL ON IMPORTANT DETAILS SUCH AS
TRACK...PCPN TYPE AND AMOUNTS. LATEST 00Z MODELS TRENDING SYSTEM
WESTWARD AS THEY TEND TO DO WITH DYNAMICALLY STRONG AND NEGATIVELY
TILTED SYSTEMS. CURRENT MODEL RUNS DO BRING COLD AIR IN ON CHRISTMAS
EVE SO KEPT PCPN TYPE ALL SNOW IN THIS PERIOD FOR NOW. MODELS STILL
SHOWING A VERY STRONG LOW DEVELOPING WITH TIGHT GRADIENT AS BLOCKY
PATTERN STALLS SYSTEM OVER GREAT LAKES REGION. ANY SNOW THAT DOES
FALL BY CHRISTMAS WILL CERTAINLY CREATE TRAVEL ISSUES AND HAVE
SIGNIFICANT IMPACTS DUE TO BLOWING AND DRIFTING. THIS REMAINS WORTHY
OF MENTION IN HWO BUT RESTRAINT SHOULD BE EXERCISED FOR NOW IN THE
FORECASTS OF TRACK AND SNOW AMOUNTS GIVEN LITTLE SKILL AT THIS TIME
RANGE.

OTHERWISE A RATHER BENIGN LONG TERM PERIOD EXPECTED LEADING UP TO
THIS POTENTIAL STORM. SEASONABLE TEMPERATURES TO START THE PERIOD
FRIDAY WITH A SUBTLE WARMING TREND INTO EARLY NEXT WEEK. SEVERAL
WEAK SHORT WAVES AND TRAPPED LOW LEVEL MOISTURE BENEATH INVERSION TO
LIKELY KEEP SKIES AT LEAST PARTLY CLOUDY IF NOT MOSTLY CLOUDY
THROUGH THE PERIOD. INITIAL SHORT WAVE AND MOISTURE SURGE MONDAY
WILL BRING INITIAL CHANCES OF PCPN INTO THE REGION.


&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1209 AM EST THU DEC 18 2014

KEPT MVFR CIGS THE ENTIRE TAF PERIOD AT BOTH SBN AND FWA WITH WEST
WINDS 7-10 KTS. EARLY EVENING UPPER AIR SOUNDINGS AND OVERNIGHT
AIRCRAFT OBSERVATIONS SHOW AN INCREASING DEPTH TO THE FRONTAL
INVERSION FROM SOUTHWEST TO NORTHEAST. AN AIRCRAFT SOUNDING AT FWA
AT 0316Z SHOWED THE BASE OF THE SUBSIDENCE INVERSION AROUND 850
MB...OR ABOUT 4000 FT ABOVE THE SFC. GIVEN UPSTREAM MOISTURE BELOW
THE INVERSION...A CONTINUED NORTHWEST TO NORTH FETCH AND THE
ADDITIONAL OF SOME LAKE MOISTURE...BELIEVE IT WILL BE DIFFICULT TO
BREAK OUT OF THE MVFR SC DECK FOR THE NEXT 24 HOURS. THEREFORE...
HAVE KEPT MVFR CIGS THE ENTIRE PERIOD.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR LMZ043-046.

&&

$$

SYNOPSIS...SKIPPER
SHORT TERM...SKIPPER
LONG TERM...LASHLEY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA








000
FXUS63 KIWX 180900
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
400 AM EST THU DEC 18 2014

.SYNOPSIS...
ISSUED AT 1240 AM EST THU DEC 18 2014

LIGHT LAKE EFFECT SNOW SHOWERS ARE POSSIBLE TODAY AS A TROF MOVES
SOUTH OVER LOWER MICHIGAN INTO NORTHERN INDIANA. THE WINDS BEHIND
THIS TROF WILL MAKE THE FETCH A LITTLE MORE FAVORABLE FOR LAKE
EFFECT SNOW. HOWEVER...LITTLE IF ANY SNOW ACCUMULATION IS
EXPECTED. HIGHS TODAY AND FRIDAY WILL BE AROUND 30 TO 35. LOWS
TONIGHT WILL BE IN THE 20S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 358 AM EST THU DEC 18 2014

UPPER AIR SOUNDINGS FROM YESTERDAY EVENING AND OVERNIGHT AIRCRAFT
OBSERVATIONS SHOWED AN INCREASING DEPTH TO THE INVERSION FROM
SOUTHWEST TO NORTHEAST. THE BASE OF THE INVERSION RANGED FROM LESS
THEN 2000 FEET AT LINCOLN IL/ILX...TO 4000 FEET AT FT WAYNE TO 5000
FEET NEAR DETROIT. OVERNIGHT SATELLITE SHOWED CLOUDS FILLING IN OVER
LAKE MICHIGAN WHERE THE INVERSION HEIGHT WAS ONLY 3000 FEET. THIS
LOW INVERSION HEIGHT WAS LIMITING LAKE EFFECT SNOW SHOWERS.  A
SURFACE TROF WILL MOVE SOUTH ACROSS LOWER MICHIGAN THIS AFTERNOON
AND INTO NORTHERN INDIANA THIS EVENING...AND HELP TO KEEP A SMALL
CHANCE FOR SNOW SHOWERS LATE TODAY AND EARLY TONIGHT. OTHERWISE...
KEPT LOW CHANCES FOR LIGHT LAKE EFFECT SNOW SHOWERS GIVEN A LOW
INVERSION HEIGHT AND A MARGINAL FETCH WITH MEAGER DELTA T VALUES
AROUND 11C. BELIEVE IT WILL BE DIFFICULT TO BREAK OUT OF THE LOW
CLOUDS WITH THIS PATTERN THROUGH TONIGHT. GIVEN ABUNDANT CLOUD
COVER...KEPT TEMPERATURES COLD TODAY WITH HIGHS ONLY IN THE LOWER
30S.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 358 AM EST THU DEC 18 2014


MOST IMPORTANT INFORMATION FIRST SO THIS LONG TERM WILL BEGIN WITH
DISCUSSION OF POSSIBLE WINTER STORM NEXT WEEK. HYPE ALREADY WELL
UNDERWAY BUT A LOT OF UNCERTAINTY REMAINS WITH RESPECT TO THE VERY
IMPORTANT AND CRITICAL DETAILS OF WHEN AND WHERE THIS STORM WILL
CREATE IMPACTS. CAUTIOUS BUT INFORMATIVE APPROACH WARRANTED GIVEN
THE DAY 6 TO 7 TIME FRAME AND A VERY ENERGETIC PACIFIC JET STREAM
WHICH IS POORLY SAMPLED. THUS NUMEROUS CRITICAL CHANGES AND
DEVIATIONS IN MODEL SOLUTIONS EXPECTED WITH EACH ITERATION OVER THE
NEXT SEVERAL DAYS. THE BROAD SYNOPTIC AGREEMENT AMONG MODELS DOES
GIVE HIGHER THAN NORMAL CONFIDENCE THAT A SUBSTANTIAL STORM SYSTEM WILL
IMPACT SOME PART OF THE EASTERN CONUS REGION BY CHRISTMAS.
HOWEVER...ALREADY SEEING MODEL ADJUSTMENTS IN POTENTIAL TIMING AND
TRACK OF SYSTEM AS WELL AS HOW FAST COLDER AIR WILL SWEEP IN.
CONFIDENCE REMAINS BELOW NORMAL ON IMPORTANT DETAILS SUCH AS
TRACK...PCPN TYPE AND AMOUNTS. LATEST 00Z MODELS TRENDING SYSTEM
WESTWARD AS THEY TEND TO DO WITH DYNAMICALLY STRONG AND NEGATIVELY
TILTED SYSTEMS. CURRENT MODEL RUNS DO BRING COLD AIR IN ON CHRISTMAS
EVE SO KEPT PCPN TYPE ALL SNOW IN THIS PERIOD FOR NOW. MODELS STILL
SHOWING A VERY STRONG LOW DEVELOPING WITH TIGHT GRADIENT AS BLOCKY
PATTERN STALLS SYSTEM OVER GREAT LAKES REGION. ANY SNOW THAT DOES
FALL BY CHRISTMAS WILL CERTAINLY CREATE TRAVEL ISSUES AND HAVE
SIGNIFICANT IMPACTS DUE TO BLOWING AND DRIFTING. THIS REMAINS WORTHY
OF MENTION IN HWO BUT RESTRAINT SHOULD BE EXERCISED FOR NOW IN THE
FORECASTS OF TRACK AND SNOW AMOUNTS GIVEN LITTLE SKILL AT THIS TIME
RANGE.

OTHERWISE A RATHER BENIGN LONG TERM PERIOD EXPECTED LEADING UP TO
THIS POTENTIAL STORM. SEASONABLE TEMPERATURES TO START THE PERIOD
FRIDAY WITH A SUBTLE WARMING TREND INTO EARLY NEXT WEEK. SEVERAL
WEAK SHORT WAVES AND TRAPPED LOW LEVEL MOISTURE BENEATH INVERSION TO
LIKELY KEEP SKIES AT LEAST PARTLY CLOUDY IF NOT MOSTLY CLOUDY
THROUGH THE PERIOD. INITIAL SHORT WAVE AND MOISTURE SURGE MONDAY
WILL BRING INITIAL CHANCES OF PCPN INTO THE REGION.


&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1209 AM EST THU DEC 18 2014

KEPT MVFR CIGS THE ENTIRE TAF PERIOD AT BOTH SBN AND FWA WITH WEST
WINDS 7-10 KTS. EARLY EVENING UPPER AIR SOUNDINGS AND OVERNIGHT
AIRCRAFT OBSERVATIONS SHOW AN INCREASING DEPTH TO THE FRONTAL
INVERSION FROM SOUTHWEST TO NORTHEAST. AN AIRCRAFT SOUNDING AT FWA
AT 0316Z SHOWED THE BASE OF THE SUBSIDENCE INVERSION AROUND 850
MB...OR ABOUT 4000 FT ABOVE THE SFC. GIVEN UPSTREAM MOISTURE BELOW
THE INVERSION...A CONTINUED NORTHWEST TO NORTH FETCH AND THE
ADDITIONAL OF SOME LAKE MOISTURE...BELIEVE IT WILL BE DIFFICULT TO
BREAK OUT OF THE MVFR SC DECK FOR THE NEXT 24 HOURS. THEREFORE...
HAVE KEPT MVFR CIGS THE ENTIRE PERIOD.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR LMZ043-046.

&&

$$

SYNOPSIS...SKIPPER
SHORT TERM...SKIPPER
LONG TERM...LASHLEY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA








000
FXUS63 KIWX 180900
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
400 AM EST THU DEC 18 2014

.SYNOPSIS...
ISSUED AT 1240 AM EST THU DEC 18 2014

LIGHT LAKE EFFECT SNOW SHOWERS ARE POSSIBLE TODAY AS A TROF MOVES
SOUTH OVER LOWER MICHIGAN INTO NORTHERN INDIANA. THE WINDS BEHIND
THIS TROF WILL MAKE THE FETCH A LITTLE MORE FAVORABLE FOR LAKE
EFFECT SNOW. HOWEVER...LITTLE IF ANY SNOW ACCUMULATION IS
EXPECTED. HIGHS TODAY AND FRIDAY WILL BE AROUND 30 TO 35. LOWS
TONIGHT WILL BE IN THE 20S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 358 AM EST THU DEC 18 2014

UPPER AIR SOUNDINGS FROM YESTERDAY EVENING AND OVERNIGHT AIRCRAFT
OBSERVATIONS SHOWED AN INCREASING DEPTH TO THE INVERSION FROM
SOUTHWEST TO NORTHEAST. THE BASE OF THE INVERSION RANGED FROM LESS
THEN 2000 FEET AT LINCOLN IL/ILX...TO 4000 FEET AT FT WAYNE TO 5000
FEET NEAR DETROIT. OVERNIGHT SATELLITE SHOWED CLOUDS FILLING IN OVER
LAKE MICHIGAN WHERE THE INVERSION HEIGHT WAS ONLY 3000 FEET. THIS
LOW INVERSION HEIGHT WAS LIMITING LAKE EFFECT SNOW SHOWERS.  A
SURFACE TROF WILL MOVE SOUTH ACROSS LOWER MICHIGAN THIS AFTERNOON
AND INTO NORTHERN INDIANA THIS EVENING...AND HELP TO KEEP A SMALL
CHANCE FOR SNOW SHOWERS LATE TODAY AND EARLY TONIGHT. OTHERWISE...
KEPT LOW CHANCES FOR LIGHT LAKE EFFECT SNOW SHOWERS GIVEN A LOW
INVERSION HEIGHT AND A MARGINAL FETCH WITH MEAGER DELTA T VALUES
AROUND 11C. BELIEVE IT WILL BE DIFFICULT TO BREAK OUT OF THE LOW
CLOUDS WITH THIS PATTERN THROUGH TONIGHT. GIVEN ABUNDANT CLOUD
COVER...KEPT TEMPERATURES COLD TODAY WITH HIGHS ONLY IN THE LOWER
30S.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 358 AM EST THU DEC 18 2014


MOST IMPORTANT INFORMATION FIRST SO THIS LONG TERM WILL BEGIN WITH
DISCUSSION OF POSSIBLE WINTER STORM NEXT WEEK. HYPE ALREADY WELL
UNDERWAY BUT A LOT OF UNCERTAINTY REMAINS WITH RESPECT TO THE VERY
IMPORTANT AND CRITICAL DETAILS OF WHEN AND WHERE THIS STORM WILL
CREATE IMPACTS. CAUTIOUS BUT INFORMATIVE APPROACH WARRANTED GIVEN
THE DAY 6 TO 7 TIME FRAME AND A VERY ENERGETIC PACIFIC JET STREAM
WHICH IS POORLY SAMPLED. THUS NUMEROUS CRITICAL CHANGES AND
DEVIATIONS IN MODEL SOLUTIONS EXPECTED WITH EACH ITERATION OVER THE
NEXT SEVERAL DAYS. THE BROAD SYNOPTIC AGREEMENT AMONG MODELS DOES
GIVE HIGHER THAN NORMAL CONFIDENCE THAT A SUBSTANTIAL STORM SYSTEM WILL
IMPACT SOME PART OF THE EASTERN CONUS REGION BY CHRISTMAS.
HOWEVER...ALREADY SEEING MODEL ADJUSTMENTS IN POTENTIAL TIMING AND
TRACK OF SYSTEM AS WELL AS HOW FAST COLDER AIR WILL SWEEP IN.
CONFIDENCE REMAINS BELOW NORMAL ON IMPORTANT DETAILS SUCH AS
TRACK...PCPN TYPE AND AMOUNTS. LATEST 00Z MODELS TRENDING SYSTEM
WESTWARD AS THEY TEND TO DO WITH DYNAMICALLY STRONG AND NEGATIVELY
TILTED SYSTEMS. CURRENT MODEL RUNS DO BRING COLD AIR IN ON CHRISTMAS
EVE SO KEPT PCPN TYPE ALL SNOW IN THIS PERIOD FOR NOW. MODELS STILL
SHOWING A VERY STRONG LOW DEVELOPING WITH TIGHT GRADIENT AS BLOCKY
PATTERN STALLS SYSTEM OVER GREAT LAKES REGION. ANY SNOW THAT DOES
FALL BY CHRISTMAS WILL CERTAINLY CREATE TRAVEL ISSUES AND HAVE
SIGNIFICANT IMPACTS DUE TO BLOWING AND DRIFTING. THIS REMAINS WORTHY
OF MENTION IN HWO BUT RESTRAINT SHOULD BE EXERCISED FOR NOW IN THE
FORECASTS OF TRACK AND SNOW AMOUNTS GIVEN LITTLE SKILL AT THIS TIME
RANGE.

OTHERWISE A RATHER BENIGN LONG TERM PERIOD EXPECTED LEADING UP TO
THIS POTENTIAL STORM. SEASONABLE TEMPERATURES TO START THE PERIOD
FRIDAY WITH A SUBTLE WARMING TREND INTO EARLY NEXT WEEK. SEVERAL
WEAK SHORT WAVES AND TRAPPED LOW LEVEL MOISTURE BENEATH INVERSION TO
LIKELY KEEP SKIES AT LEAST PARTLY CLOUDY IF NOT MOSTLY CLOUDY
THROUGH THE PERIOD. INITIAL SHORT WAVE AND MOISTURE SURGE MONDAY
WILL BRING INITIAL CHANCES OF PCPN INTO THE REGION.


&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1209 AM EST THU DEC 18 2014

KEPT MVFR CIGS THE ENTIRE TAF PERIOD AT BOTH SBN AND FWA WITH WEST
WINDS 7-10 KTS. EARLY EVENING UPPER AIR SOUNDINGS AND OVERNIGHT
AIRCRAFT OBSERVATIONS SHOW AN INCREASING DEPTH TO THE FRONTAL
INVERSION FROM SOUTHWEST TO NORTHEAST. AN AIRCRAFT SOUNDING AT FWA
AT 0316Z SHOWED THE BASE OF THE SUBSIDENCE INVERSION AROUND 850
MB...OR ABOUT 4000 FT ABOVE THE SFC. GIVEN UPSTREAM MOISTURE BELOW
THE INVERSION...A CONTINUED NORTHWEST TO NORTH FETCH AND THE
ADDITIONAL OF SOME LAKE MOISTURE...BELIEVE IT WILL BE DIFFICULT TO
BREAK OUT OF THE MVFR SC DECK FOR THE NEXT 24 HOURS. THEREFORE...
HAVE KEPT MVFR CIGS THE ENTIRE PERIOD.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR LMZ043-046.

&&

$$

SYNOPSIS...SKIPPER
SHORT TERM...SKIPPER
LONG TERM...LASHLEY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA







000
FXUS63 KIWX 180558
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1258 AM EST THU DEC 18 2014

.SYNOPSIS...
ISSUED AT 1240 AM EST THU DEC 18 2014

LIGHT LAKE EFFECT SNOW SHOWERS ARE POSSIBLE TODAY AS A TROF MOVES
SOUTH OVER LOWER MICHIGAN INTO NORTHERN INDIANA. THE WINDS BEHIND
THIS TROF WILL MAKE THE FETCH A LITTLE MORE FAVORABLE FOR LAKE
EFFECT SNOW. HOWEVER...LITTLE IF ANY SNOW ACCUMULATION IS
EXPECTED. HIGHS TODAY AND FRIDAY WILL BE AROUND 30 TO 35. LOWS
THURSDAY NIGHT WILL BE IN THE 20S.

&&

.UPDATE...
ISSUED AT 847 PM EST WED DEC 17 2014

NO SIGNIFICANT CHANGES MADE TO FORECAST THIS EVENING. LIGHT SNOW
HAS DIMINISHED OVER THE PAST FEW HOURS AS MID LEVEL SUBSIDENCE HAS
STRENGTHENED SUBSTANTIALLY WITH PASSAGE OF SHEARED VORT MAX NOW
PUSHING ACROSS THE EASTERN GREAT LAKES. ANOTHER WEAKER UPSTREAM
VORT ROUNDING BROADER UPPER TROUGH SHOULD TRACK ACROSS SOUTHERN
LOWER MICHIGAN DURING THE OVERNIGHT HOURS WHICH MAY AID IN SOME
REDEVELOPMENT OF LIGHT LAKE EFFECT SNOW SHOWERS. UPDATED ZONES
SENT TO ACCOUNT FOR CURRENT POP TRENDS AND LIMITED POPS TO LOW
CHANCE OVERNIGHT. SOME SLIGHT DOWNWARD ADJUSTMENT ALSO MADE TO
MINS...PARTICULARLY ACROSS THE FAR SOUTHWEST WHERE SOME PARTIAL
CLEARING IS POSSIBLE LATE TONIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 240 PM EST WED DEC 17 2014

CURRENT TROUGH SWINGING ACROSS THE GREAT LAKES THIS EVENING IS
SHOWING SOME EROSION IN THE CLOUD DECK BEHIND IT ACROSS WESTERN
ILLINOIS. THE QUESTION IS HOW FAR EAST THIS PARTIAL CLEARING MOVES
TOWARDS OUR AREA WHILE AT THE SAME TIME SOUTHERN PLAINS CLOUDS
ADVANCE NORTHEAST TOWARD THAT CLEARING PATCH. END RESULT MAY BE
SOME BRIEF AND PARTIAL CLEARING FOR SOME OF THE SOUTHWEST
COUNTIES.

THE LIGHT SNOW THAT HAS BEEN OCCURRING WILL BE CARRIED AS A CHANCE
THROUGHOUT THE NIGHT IN THE SAME AREAS CURRENTLY AFFECTED. STILL
EXPECT NO MORE THAN A LIGHT COVERING OF SNOW AT WORST FOR SOME
AREAS. MAINLY CLOUDY SKY AND FLOW TURNING MORE OFF THE LAKE SHOULD
KEEP MIN TEMPS TO NO LOWER THAN LOWER 20S TONIGHT.

THURSDAY...THE SOUTHERN PLAINS SYSTEM IS DEPICTED BY MOST MODELS
TO WEAKEN AS IT MOVES INTO RIDGE BEHIND CURRENT TROUGH IN OUR
AREA. NET RESULT WILL BE MAINTENANCE OF CLOUD COVER AND LOW THREAT
FOR LIGHT...NON-ACCUMULATING SNOW THURSDAY AFTERNOON. TEMPERATURES
WILL REBOUND LITTLE...CLIMBING NO MORE THAN LOWER 30S IN THE AFTERNOON.

&&

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 240 PM EST WED DEC 17 2014

IN THE WAKE OF THURSDAY TROUGH EXITING THE AREA MODELS SHOW HIGH
PRESSURE BUILDING OVER THE GREAT LAKES AND AIR DRYING OUT
SUGGESTIVE OF DIMINISHED CLOUD COVER. HESITANT TO DELVE TO FAR
INTO PARTLY CLOUDY SKY GIVEN PERSISTENCE OF LOW CLOUD DECKS
WITHOUT MUCH WIND TO SCOUR THEM OUT. MINIMUM TEMPS ON TRACK IN
LOW TO MID 20S AND DIDN`T CHANGE MUCH.

FRIDAY MAY SHOW A FEW PEAKS AT THE SUN WITH NO WEATHER TO SPEAK
OF. THIS SHOULD ALLOW MAX TEMPS TO REACH MID AND UPPER 30S UNDER
LIGHT EAST WIND.

FRIDAY NIGHT INTO SATURDAY MODELS CONTINUE THE TREND OF NEXT
APPROACHING SYSTEM TO REACH NO FURTHER NORTH THAN SOUTHERN INDIANA
WITH PRECIPITATION AND AN OVERCAST SKY FOR OUR AREA.

HIGH PRESSURE WILL ESSENTIALLY REMAIN IN CONTROL FROM FRIDAY NIGHT
INTO MONDAY AFTERNOON. BEYOND THAT TIME FRAME FAIRLY SIGNIFICANT
SYSTEM IS EXPECTED TO MOVE INTO MIDWEST BUT LATEST TRENDS ARE A
BIT WARMER LEANING TO MORE RAIN THAN SNOW. WITH HIGH UNCERTAINTY
AT TIMES WILL KEEP A RAIN SNOW MIX START CONVERTING TO ALL RAIN BY
TUESDAY THEN BACK TO A MIX OR ALL SNOW WEDNESDAY. AGAIN
UNCERTAINTY IS HIGH AND MANY MORE MODEL RUNS SHOULD SORT THIS OUT.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1209 AM EST THU DEC 18 2014

KEPT MVFR CIGS THE ENTIRE TAF PERIOD AT BOTH SBN AND FWA WITH WEST
WINDS 7-10 KTS. EARLY EVENING UPPER AIR SOUNDINGS AND OVERNIGHT
AIRCRAFT OBSERVATIONS SHOW AN INCREASING DEPTH TO THE FRONTAL
INVERSION FROM SOUTHWEST TO NORTHEAST. AN AIRCRAFT SOUNDING AT FWA
AT 0316Z SHOWED THE BASE OF THE SUBSIDENCE INVERSION AROUND 850
MB...OR ABOUT 4000 FT ABOVE THE SFC. GIVEN UPSTREAM MOISTURE BELOW
THE INVERSION...A CONTINUED NORTHWEST TO NORTH FETCH AND THE
ADDITIONAL OF SOME LAKE MOISTURE...BELIEVE IT WILL BE DIFFICULT TO
BREAK OUT OF THE MVFR SC DECK FOR THE NEXT 24 HOURS. THEREFORE...
HAVE KEPT MVFR CIGS THE ENTIRE PERIOD.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR LMZ043-046.

&&

$$

UPDATE...MARSILI/SKIPPER
SYNOPSIS...MARSILI
SHORT TERM...TUCEK
LONG TERM...TUCEK
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA







000
FXUS63 KIWX 180558
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1258 AM EST THU DEC 18 2014

.SYNOPSIS...
ISSUED AT 1240 AM EST THU DEC 18 2014

LIGHT LAKE EFFECT SNOW SHOWERS ARE POSSIBLE TODAY AS A TROF MOVES
SOUTH OVER LOWER MICHIGAN INTO NORTHERN INDIANA. THE WINDS BEHIND
THIS TROF WILL MAKE THE FETCH A LITTLE MORE FAVORABLE FOR LAKE
EFFECT SNOW. HOWEVER...LITTLE IF ANY SNOW ACCUMULATION IS
EXPECTED. HIGHS TODAY AND FRIDAY WILL BE AROUND 30 TO 35. LOWS
THURSDAY NIGHT WILL BE IN THE 20S.

&&

.UPDATE...
ISSUED AT 847 PM EST WED DEC 17 2014

NO SIGNIFICANT CHANGES MADE TO FORECAST THIS EVENING. LIGHT SNOW
HAS DIMINISHED OVER THE PAST FEW HOURS AS MID LEVEL SUBSIDENCE HAS
STRENGTHENED SUBSTANTIALLY WITH PASSAGE OF SHEARED VORT MAX NOW
PUSHING ACROSS THE EASTERN GREAT LAKES. ANOTHER WEAKER UPSTREAM
VORT ROUNDING BROADER UPPER TROUGH SHOULD TRACK ACROSS SOUTHERN
LOWER MICHIGAN DURING THE OVERNIGHT HOURS WHICH MAY AID IN SOME
REDEVELOPMENT OF LIGHT LAKE EFFECT SNOW SHOWERS. UPDATED ZONES
SENT TO ACCOUNT FOR CURRENT POP TRENDS AND LIMITED POPS TO LOW
CHANCE OVERNIGHT. SOME SLIGHT DOWNWARD ADJUSTMENT ALSO MADE TO
MINS...PARTICULARLY ACROSS THE FAR SOUTHWEST WHERE SOME PARTIAL
CLEARING IS POSSIBLE LATE TONIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 240 PM EST WED DEC 17 2014

CURRENT TROUGH SWINGING ACROSS THE GREAT LAKES THIS EVENING IS
SHOWING SOME EROSION IN THE CLOUD DECK BEHIND IT ACROSS WESTERN
ILLINOIS. THE QUESTION IS HOW FAR EAST THIS PARTIAL CLEARING MOVES
TOWARDS OUR AREA WHILE AT THE SAME TIME SOUTHERN PLAINS CLOUDS
ADVANCE NORTHEAST TOWARD THAT CLEARING PATCH. END RESULT MAY BE
SOME BRIEF AND PARTIAL CLEARING FOR SOME OF THE SOUTHWEST
COUNTIES.

THE LIGHT SNOW THAT HAS BEEN OCCURRING WILL BE CARRIED AS A CHANCE
THROUGHOUT THE NIGHT IN THE SAME AREAS CURRENTLY AFFECTED. STILL
EXPECT NO MORE THAN A LIGHT COVERING OF SNOW AT WORST FOR SOME
AREAS. MAINLY CLOUDY SKY AND FLOW TURNING MORE OFF THE LAKE SHOULD
KEEP MIN TEMPS TO NO LOWER THAN LOWER 20S TONIGHT.

THURSDAY...THE SOUTHERN PLAINS SYSTEM IS DEPICTED BY MOST MODELS
TO WEAKEN AS IT MOVES INTO RIDGE BEHIND CURRENT TROUGH IN OUR
AREA. NET RESULT WILL BE MAINTENANCE OF CLOUD COVER AND LOW THREAT
FOR LIGHT...NON-ACCUMULATING SNOW THURSDAY AFTERNOON. TEMPERATURES
WILL REBOUND LITTLE...CLIMBING NO MORE THAN LOWER 30S IN THE AFTERNOON.

&&

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 240 PM EST WED DEC 17 2014

IN THE WAKE OF THURSDAY TROUGH EXITING THE AREA MODELS SHOW HIGH
PRESSURE BUILDING OVER THE GREAT LAKES AND AIR DRYING OUT
SUGGESTIVE OF DIMINISHED CLOUD COVER. HESITANT TO DELVE TO FAR
INTO PARTLY CLOUDY SKY GIVEN PERSISTENCE OF LOW CLOUD DECKS
WITHOUT MUCH WIND TO SCOUR THEM OUT. MINIMUM TEMPS ON TRACK IN
LOW TO MID 20S AND DIDN`T CHANGE MUCH.

FRIDAY MAY SHOW A FEW PEAKS AT THE SUN WITH NO WEATHER TO SPEAK
OF. THIS SHOULD ALLOW MAX TEMPS TO REACH MID AND UPPER 30S UNDER
LIGHT EAST WIND.

FRIDAY NIGHT INTO SATURDAY MODELS CONTINUE THE TREND OF NEXT
APPROACHING SYSTEM TO REACH NO FURTHER NORTH THAN SOUTHERN INDIANA
WITH PRECIPITATION AND AN OVERCAST SKY FOR OUR AREA.

HIGH PRESSURE WILL ESSENTIALLY REMAIN IN CONTROL FROM FRIDAY NIGHT
INTO MONDAY AFTERNOON. BEYOND THAT TIME FRAME FAIRLY SIGNIFICANT
SYSTEM IS EXPECTED TO MOVE INTO MIDWEST BUT LATEST TRENDS ARE A
BIT WARMER LEANING TO MORE RAIN THAN SNOW. WITH HIGH UNCERTAINTY
AT TIMES WILL KEEP A RAIN SNOW MIX START CONVERTING TO ALL RAIN BY
TUESDAY THEN BACK TO A MIX OR ALL SNOW WEDNESDAY. AGAIN
UNCERTAINTY IS HIGH AND MANY MORE MODEL RUNS SHOULD SORT THIS OUT.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1209 AM EST THU DEC 18 2014

KEPT MVFR CIGS THE ENTIRE TAF PERIOD AT BOTH SBN AND FWA WITH WEST
WINDS 7-10 KTS. EARLY EVENING UPPER AIR SOUNDINGS AND OVERNIGHT
AIRCRAFT OBSERVATIONS SHOW AN INCREASING DEPTH TO THE FRONTAL
INVERSION FROM SOUTHWEST TO NORTHEAST. AN AIRCRAFT SOUNDING AT FWA
AT 0316Z SHOWED THE BASE OF THE SUBSIDENCE INVERSION AROUND 850
MB...OR ABOUT 4000 FT ABOVE THE SFC. GIVEN UPSTREAM MOISTURE BELOW
THE INVERSION...A CONTINUED NORTHWEST TO NORTH FETCH AND THE
ADDITIONAL OF SOME LAKE MOISTURE...BELIEVE IT WILL BE DIFFICULT TO
BREAK OUT OF THE MVFR SC DECK FOR THE NEXT 24 HOURS. THEREFORE...
HAVE KEPT MVFR CIGS THE ENTIRE PERIOD.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR LMZ043-046.

&&

$$

UPDATE...MARSILI/SKIPPER
SYNOPSIS...MARSILI
SHORT TERM...TUCEK
LONG TERM...TUCEK
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA








000
FXUS63 KIWX 180230
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
930 PM EST WED DEC 17 2014

.SYNOPSIS...
ISSUED AT 730 PM EST WED DEC 17 2014

OCCASIONAL LAKE EFFECT SNOW FLURRIES AND LIGHT SNOW WILL CONTINUE
THROUGH THURSDAY...BUT LITTLE TO NO SNOW ACCUMULATION IS EXPECTED.
ANOTHER UPPER LEVEL SYSTEM WILL APPROACH THE REGION THURSDAY AND
WEAKEN AS IT LIFTS INTO INDIANA DURING THE AFTERNOON BRINGING A
SLIGHT CHANCE OF SOME LIGHT SNOW. LOW TEMPERATURES TONIGHT WILL
DROP INTO THE MID 20S...WITH HIGH TEMPERATURES ON THURSDAY
REACHING BACK INTO THE LOWER 30S.

&&

.UPDATE...
ISSUED AT 847 PM EST WED DEC 17 2014

NO SIGNIFICANT CHANGES MADE TO FORECAST THIS EVENING. LIGHT SNOW
HAS DIMINISHED OVER THE PAST FEW HOURS AS MID LEVEL SUBSIDENCE HAS
STRENGTHENED SUBSTANTIALLY WITH PASSAGE OF SHEARED VORT MAX NOW
PUSHING ACROSS THE EASTERN GREAT LAKES. ANOTHER WEAKER UPSTREAM
VORT ROUNDING BROADER UPPER TROUGH SHOULD TRACK ACROSS SOUTHERN
LOWER MICHIGAN DURING THE OVERNIGHT HOURS WHICH MAY AID IN SOME
REDEVELOPMENT OF LIGHT LAKE EFFECT SNOW SHOWERS. UPDATED ZONES
SENT TO ACCOUNT FOR CURRENT POP TRENDS AND LIMITED POPS TO LOW
CHANCE OVERNIGHT. SOME SLIGHT DOWNWARD ADJUSTMENT ALSO MADE TO
MINS...PARTICULARLY ACROSS THE FAR SOUTHWEST WHERE SOME PARTIAL
CLEARING IS POSSIBLE LATE TONIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 240 PM EST WED DEC 17 2014

CURRENT TROUGH SWINGING ACROSS THE GREAT LAKES THIS EVENING IS
SHOWING SOME EROSION IN THE CLOUD DECK BEHIND IT ACROSS WESTERN
ILLINOIS. THE QUESTION IS HOW FAR EAST THIS PARTIAL CLEARING MOVES
TOWARDS OUR AREA WHILE AT THE SAME TIME SOUTHERN PLAINS CLOUDS
ADVANCE NORTHEAST TOWARD THAT CLEARING PATCH. END RESULT MAY BE
SOME BRIEF AND PARTIAL CLEARING FOR SOME OF THE SOUTHWEST
COUNTIES.

THE LIGHT SNOW THAT HAS BEEN OCCURRING WILL BE CARRIED AS A CHANCE
THROUGHOUT THE NIGHT IN THE SAME AREAS CURRENTLY AFFECTED. STILL
EXPECT NO MORE THAN A LIGHT COVERING OF SNOW AT WORST FOR SOME
AREAS. MAINLY CLOUDY SKY AND FLOW TURNING MORE OFF THE LAKE SHOULD
KEEP MIN TEMPS TO NO LOWER THAN LOWER 20S TONIGHT.

THURSDAY...THE SOUTHERN PLAINS SYSTEM IS DEPICTED BY MOST MODELS
TO WEAKEN AS IT MOVES INTO RIDGE BEHIND CURRENT TROUGH IN OUR
AREA. NET RESULT WILL BE MAINTENANCE OF CLOUD COVER AND LOW THREAT
FOR LIGHT...NON-ACCUMULATING SNOW THURSDAY AFTERNOON. TEMPERATURES
WILL REBOUND LITTLE...CLIMBING NO MORE THAN LOWER 30S IN THE AFTERNOON.

&&

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 240 PM EST WED DEC 17 2014

IN THE WAKE OF THURSDAY TROUGH EXITING THE AREA MODELS SHOW HIGH
PRESSURE BUILDING OVER THE GREAT LAKES AND AIR DRYING OUT
SUGGESTIVE OF DIMINISHED CLOUD COVER. HESITANT TO DELVE TO FAR
INTO PARTLY CLOUDY SKY GIVEN PERSISTENCE OF LOW CLOUD DECKS
WITHOUT MUCH WIND TO SCOUR THEM OUT. MINIMUM TEMPS ON TRACK IN
LOW TO MID 20S AND DIDN`T CHANGE MUCH.

FRIDAY MAY SHOW A FEW PEAKS AT THE SUN WITH NO WEATHER TO SPEAK
OF. THIS SHOULD ALLOW MAX TEMPS TO REACH MID AND UPPER 30S UNDER
LIGHT EAST WIND.

FRIDAY NIGHT INTO SATURDAY MODELS CONTINUE THE TREND OF NEXT
APPROACHING SYSTEM TO REACH NO FURTHER NORTH THAN SOUTHERN INDIANA
WITH PRECIPITATION AND AN OVERCAST SKY FOR OUR AREA.

HIGH PRESSURE WILL ESSENTIALLY REMAIN IN CONTROL FROM FRIDAY NIGHT
INTO MONDAY AFTERNOON. BEYOND THAT TIME FRAME FAIRLY SIGNIFICANT
SYSTEM IS EXPECTED TO MOVE INTO MIDWEST BUT LATEST TRENDS ARE A
BIT WARMER LEANING TO MORE RAIN THAN SNOW. WITH HIGH UNCERTAINTY
AT TIMES WILL KEEP A RAIN SNOW MIX START CONVERTING TO ALL RAIN BY
TUESDAY THEN BACK TO A MIX OR ALL SNOW WEDNESDAY. AGAIN
UNCERTAINTY IS HIGH AND MANY MORE MODEL RUNS SHOULD SORT THIS OUT.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 730 PM EST WED DEC 17 2014

SHEARED UPPER LEVEL SHORT WAVE WILL CONTINUE TO SHIFT EAST OF THE
AREA TO THE EASTERN GREAT LAKES TONIGHT. THIS WILL RESULT IN SOME
SUBTLE VEERING OF LOW LEVEL WINDS TO PROVIDE A FAVORABLE FETCH FOR
SOME VERY LIGHT LAKE EFFECT SNOW SHOWERS OR PERHAPS POCKETS OF
VERY LIGHT PATCHY DRIZZLE/FREEZING DRIZZLE. ANY PRECIP SHOULD BE
QUITE LIGHT GIVEN STRONG MID LEVEL SUBSIDENCE IN WAKE OF DEPARTING
WAVE AND DRY MID LEVEL PROFILES. WHILE PERIODS OF FLURRIES/LIGHTS
SNOW SHOWERS ARE POSSIBLE THROUGH THURSDAY...TIMING REMAINS QUITE
DIFFICULT TO PIN DOWN...AND WITH EXPECTATION OF NO ACCUMULATION OR
NOTABLE VSBY RESTRICTIONS....WILL RUN WITH DRY TAFS FOR THE 00Z
CYCLE. SYNOPTIC SUBSIDENCE WILL KEEP INVERSION HEIGHTS RELATIVELY
CONSISTENT AND THUS WILL MAINTAIN 2-3K FT CIGS THROUGH THE PERIOD.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EST THURSDAY FOR LMZ043-046.

&&

$$

UPDATE...MARSILI
SYNOPSIS...MARSILI
SHORT TERM...TUCEK
LONG TERM...TUCEK
AVIATION...MARSILI


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA








000
FXUS63 KIWX 180230
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
930 PM EST WED DEC 17 2014

.SYNOPSIS...
ISSUED AT 730 PM EST WED DEC 17 2014

OCCASIONAL LAKE EFFECT SNOW FLURRIES AND LIGHT SNOW WILL CONTINUE
THROUGH THURSDAY...BUT LITTLE TO NO SNOW ACCUMULATION IS EXPECTED.
ANOTHER UPPER LEVEL SYSTEM WILL APPROACH THE REGION THURSDAY AND
WEAKEN AS IT LIFTS INTO INDIANA DURING THE AFTERNOON BRINGING A
SLIGHT CHANCE OF SOME LIGHT SNOW. LOW TEMPERATURES TONIGHT WILL
DROP INTO THE MID 20S...WITH HIGH TEMPERATURES ON THURSDAY
REACHING BACK INTO THE LOWER 30S.

&&

.UPDATE...
ISSUED AT 847 PM EST WED DEC 17 2014

NO SIGNIFICANT CHANGES MADE TO FORECAST THIS EVENING. LIGHT SNOW
HAS DIMINISHED OVER THE PAST FEW HOURS AS MID LEVEL SUBSIDENCE HAS
STRENGTHENED SUBSTANTIALLY WITH PASSAGE OF SHEARED VORT MAX NOW
PUSHING ACROSS THE EASTERN GREAT LAKES. ANOTHER WEAKER UPSTREAM
VORT ROUNDING BROADER UPPER TROUGH SHOULD TRACK ACROSS SOUTHERN
LOWER MICHIGAN DURING THE OVERNIGHT HOURS WHICH MAY AID IN SOME
REDEVELOPMENT OF LIGHT LAKE EFFECT SNOW SHOWERS. UPDATED ZONES
SENT TO ACCOUNT FOR CURRENT POP TRENDS AND LIMITED POPS TO LOW
CHANCE OVERNIGHT. SOME SLIGHT DOWNWARD ADJUSTMENT ALSO MADE TO
MINS...PARTICULARLY ACROSS THE FAR SOUTHWEST WHERE SOME PARTIAL
CLEARING IS POSSIBLE LATE TONIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 240 PM EST WED DEC 17 2014

CURRENT TROUGH SWINGING ACROSS THE GREAT LAKES THIS EVENING IS
SHOWING SOME EROSION IN THE CLOUD DECK BEHIND IT ACROSS WESTERN
ILLINOIS. THE QUESTION IS HOW FAR EAST THIS PARTIAL CLEARING MOVES
TOWARDS OUR AREA WHILE AT THE SAME TIME SOUTHERN PLAINS CLOUDS
ADVANCE NORTHEAST TOWARD THAT CLEARING PATCH. END RESULT MAY BE
SOME BRIEF AND PARTIAL CLEARING FOR SOME OF THE SOUTHWEST
COUNTIES.

THE LIGHT SNOW THAT HAS BEEN OCCURRING WILL BE CARRIED AS A CHANCE
THROUGHOUT THE NIGHT IN THE SAME AREAS CURRENTLY AFFECTED. STILL
EXPECT NO MORE THAN A LIGHT COVERING OF SNOW AT WORST FOR SOME
AREAS. MAINLY CLOUDY SKY AND FLOW TURNING MORE OFF THE LAKE SHOULD
KEEP MIN TEMPS TO NO LOWER THAN LOWER 20S TONIGHT.

THURSDAY...THE SOUTHERN PLAINS SYSTEM IS DEPICTED BY MOST MODELS
TO WEAKEN AS IT MOVES INTO RIDGE BEHIND CURRENT TROUGH IN OUR
AREA. NET RESULT WILL BE MAINTENANCE OF CLOUD COVER AND LOW THREAT
FOR LIGHT...NON-ACCUMULATING SNOW THURSDAY AFTERNOON. TEMPERATURES
WILL REBOUND LITTLE...CLIMBING NO MORE THAN LOWER 30S IN THE AFTERNOON.

&&

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 240 PM EST WED DEC 17 2014

IN THE WAKE OF THURSDAY TROUGH EXITING THE AREA MODELS SHOW HIGH
PRESSURE BUILDING OVER THE GREAT LAKES AND AIR DRYING OUT
SUGGESTIVE OF DIMINISHED CLOUD COVER. HESITANT TO DELVE TO FAR
INTO PARTLY CLOUDY SKY GIVEN PERSISTENCE OF LOW CLOUD DECKS
WITHOUT MUCH WIND TO SCOUR THEM OUT. MINIMUM TEMPS ON TRACK IN
LOW TO MID 20S AND DIDN`T CHANGE MUCH.

FRIDAY MAY SHOW A FEW PEAKS AT THE SUN WITH NO WEATHER TO SPEAK
OF. THIS SHOULD ALLOW MAX TEMPS TO REACH MID AND UPPER 30S UNDER
LIGHT EAST WIND.

FRIDAY NIGHT INTO SATURDAY MODELS CONTINUE THE TREND OF NEXT
APPROACHING SYSTEM TO REACH NO FURTHER NORTH THAN SOUTHERN INDIANA
WITH PRECIPITATION AND AN OVERCAST SKY FOR OUR AREA.

HIGH PRESSURE WILL ESSENTIALLY REMAIN IN CONTROL FROM FRIDAY NIGHT
INTO MONDAY AFTERNOON. BEYOND THAT TIME FRAME FAIRLY SIGNIFICANT
SYSTEM IS EXPECTED TO MOVE INTO MIDWEST BUT LATEST TRENDS ARE A
BIT WARMER LEANING TO MORE RAIN THAN SNOW. WITH HIGH UNCERTAINTY
AT TIMES WILL KEEP A RAIN SNOW MIX START CONVERTING TO ALL RAIN BY
TUESDAY THEN BACK TO A MIX OR ALL SNOW WEDNESDAY. AGAIN
UNCERTAINTY IS HIGH AND MANY MORE MODEL RUNS SHOULD SORT THIS OUT.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 730 PM EST WED DEC 17 2014

SHEARED UPPER LEVEL SHORT WAVE WILL CONTINUE TO SHIFT EAST OF THE
AREA TO THE EASTERN GREAT LAKES TONIGHT. THIS WILL RESULT IN SOME
SUBTLE VEERING OF LOW LEVEL WINDS TO PROVIDE A FAVORABLE FETCH FOR
SOME VERY LIGHT LAKE EFFECT SNOW SHOWERS OR PERHAPS POCKETS OF
VERY LIGHT PATCHY DRIZZLE/FREEZING DRIZZLE. ANY PRECIP SHOULD BE
QUITE LIGHT GIVEN STRONG MID LEVEL SUBSIDENCE IN WAKE OF DEPARTING
WAVE AND DRY MID LEVEL PROFILES. WHILE PERIODS OF FLURRIES/LIGHTS
SNOW SHOWERS ARE POSSIBLE THROUGH THURSDAY...TIMING REMAINS QUITE
DIFFICULT TO PIN DOWN...AND WITH EXPECTATION OF NO ACCUMULATION OR
NOTABLE VSBY RESTRICTIONS....WILL RUN WITH DRY TAFS FOR THE 00Z
CYCLE. SYNOPTIC SUBSIDENCE WILL KEEP INVERSION HEIGHTS RELATIVELY
CONSISTENT AND THUS WILL MAINTAIN 2-3K FT CIGS THROUGH THE PERIOD.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EST THURSDAY FOR LMZ043-046.

&&

$$

UPDATE...MARSILI
SYNOPSIS...MARSILI
SHORT TERM...TUCEK
LONG TERM...TUCEK
AVIATION...MARSILI


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA







000
FXUS63 KIWX 180039
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
739 PM EST WED DEC 17 2014

.SYNOPSIS...
ISSUED AT 730 PM EST WED DEC 17 2014

OCCASIONAL LAKE EFFECT SNOW FLURRIES AND LIGHT SNOW WILL CONTINUE
THROUGH THURSDAY...BUT LITTLE TO NO SNOW ACCUMULATION IS EXPECTED.
ANOTHER UPPER LEVEL SYSTEM WILL APPROACH THE REGION THURSDAY AND
WEAKEN AS IT LIFTS INTO INDIANA DURING THE AFTERNOON BRINGING A
SLIGHT CHANCE OF SOME LIGHT SNOW. LOW TEMPERATURES TONIGHT WILL
DROP INTO THE MID 20S...WITH HIGH TEMPERATURES ON THURSDAY
REACHING BACK INTO THE LOWER 30S.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 240 PM EST WED DEC 17 2014

CURRENT TROUGH SWINGING ACROSS THE GREAT LAKES THIS EVENING IS
SHOWING SOME EROSION IN THE CLOUD DECK BEHIND IT ACROSS WESTERN
ILLINOIS. THE QUESTION IS HOW FAR EAST THIS PARTIAL CLEARING MOVES
TOWARDS OUR AREA WHILE AT THE SAME TIME SOUTHERN PLAINS CLOUDS
ADVANCE NORTHEAST TOWARD THAT CLEARING PATCH. END RESULT MAY BE
SOME BRIEF AND PARTIAL CLEARING FOR SOME OF THE SOUTHWEST
COUNTIES.

THE LIGHT SNOW THAT HAS BEEN OCCURRING WILL BE CARRIED AS A CHANCE
THROUGHOUT THE NIGHT IN THE SAME AREAS CURRENTLY AFFECTED. STILL
EXPECT NO MORE THAN A LIGHT COVERING OF SNOW AT WORST FOR SOME
AREAS. MAINLY CLOUDY SKY AND FLOW TURNING MORE OFF THE LAKE SHOULD
KEEP MIN TEMPS TO NO LOWER THAN LOWER 20S TONIGHT.

THURSDAY...THE SOUTHERN PLAINS SYSTEM IS DEPICTED BY MOST MODELS
TO WEAKEN AS IT MOVES INTO RIDGE BEHIND CURRENT TROUGH IN OUR
AREA. NET RESULT WILL BE MAINTENANCE OF CLOUD COVER AND LOW THREAT
FOR LIGHT...NON-ACCUMULATING SNOW THURSDAY AFTERNOON. TEMPERATURES
WILL REBOUND LITTLE...CLIMBING NO MORE THAN LOWER 30S IN THE AFTERNOON.

&&

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 240 PM EST WED DEC 17 2014

IN THE WAKE OF THURSDAY TROUGH EXITING THE AREA MODELS SHOW HIGH
PRESSURE BUILDING OVER THE GREAT LAKES AND AIR DRYING OUT
SUGGESTIVE OF DIMINISHED CLOUD COVER. HESITANT TO DELVE TO FAR
INTO PARTLY CLOUDY SKY GIVEN PERSISTENCE OF LOW CLOUD DECKS
WITHOUT MUCH WIND TO SCOUR THEM OUT. MINIMUM TEMPS ON TRACK IN
LOW TO MID 20S AND DIDN`T CHANGE MUCH.

FRIDAY MAY SHOW A FEW PEAKS AT THE SUN WITH NO WEATHER TO SPEAK
OF. THIS SHOULD ALLOW MAX TEMPS TO REACH MID AND UPPER 30S UNDER
LIGHT EAST WIND.

FRIDAY NIGHT INTO SATURDAY MODELS CONTINUE THE TREND OF NEXT
APPROACHING SYSTEM TO REACH NO FURTHER NORTH THAN SOUTHERN INDIANA
WITH PRECIPITATION AND AN OVERCAST SKY FOR OUR AREA.

HIGH PRESSURE WILL ESSENTIALLY REMAIN IN CONTROL FROM FRIDAY NIGHT
INTO MONDAY AFTERNOON. BEYOND THAT TIME FRAME FAIRLY SIGNIFICANT
SYSTEM IS EXPECTED TO MOVE INTO MIDWEST BUT LATEST TRENDS ARE A
BIT WARMER LEANING TO MORE RAIN THAN SNOW. WITH HIGH UNCERTAINTY
AT TIMES WILL KEEP A RAIN SNOW MIX START CONVERTING TO ALL RAIN BY
TUESDAY THEN BACK TO A MIX OR ALL SNOW WEDNESDAY. AGAIN
UNCERTAINTY IS HIGH AND MANY MORE MODEL RUNS SHOULD SORT THIS OUT.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 730 PM EST WED DEC 17 2014

SHEARED UPPER LEVEL SHORT WAVE WILL CONTINUE TO SHIFT EAST OF THE
AREA TO THE EASTERN GREAT LAKES TONIGHT. THIS WILL RESULT IN SOME
SUBTLE VEERING OF LOW LEVEL WINDS TO PROVIDE A FAVORABLE FETCH FOR
SOME VERY LIGHT LAKE EFFECT SNOW SHOWERS OR PERHAPS POCKETS OF
VERY LIGHT PATCHY DRIZZLE/FREEZING DRIZZLE. ANY PRECIP SHOULD BE
QUITE LIGHT GIVEN STRONG MID LEVEL SUBSIDENCE IN WAKE OF DEPARTING
WAVE AND DRY MID LEVEL PROFILES. WHILE PERIODS OF FLURRIES/LIGHTS
SNOW SHOWERS ARE POSSIBLE THROUGH THURSDAY...TIMING REMAINS QUITE
DIFFICULT TO PIN DOWN...AND WITH EXPECTATION OF NO ACCUMULATION OR
NOTABLE VSBY RESTRICTIONS....WILL RUN WITH DRY TAFS FOR THE 00Z
CYCLE. SYNOPTIC SUBSIDENCE WILL KEEP INVERSION HEIGHTS RELATIVELY
CONSISTENT AND THUS WILL MAINTAIN 2-3K FT CIGS THROUGH THE PERIOD.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EST THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...MARSILI
SHORT TERM...TUCEK
LONG TERM...TUCEK
AVIATION...MARSILI


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA







000
FXUS63 KIWX 180039
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
739 PM EST WED DEC 17 2014

.SYNOPSIS...
ISSUED AT 730 PM EST WED DEC 17 2014

OCCASIONAL LAKE EFFECT SNOW FLURRIES AND LIGHT SNOW WILL CONTINUE
THROUGH THURSDAY...BUT LITTLE TO NO SNOW ACCUMULATION IS EXPECTED.
ANOTHER UPPER LEVEL SYSTEM WILL APPROACH THE REGION THURSDAY AND
WEAKEN AS IT LIFTS INTO INDIANA DURING THE AFTERNOON BRINGING A
SLIGHT CHANCE OF SOME LIGHT SNOW. LOW TEMPERATURES TONIGHT WILL
DROP INTO THE MID 20S...WITH HIGH TEMPERATURES ON THURSDAY
REACHING BACK INTO THE LOWER 30S.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 240 PM EST WED DEC 17 2014

CURRENT TROUGH SWINGING ACROSS THE GREAT LAKES THIS EVENING IS
SHOWING SOME EROSION IN THE CLOUD DECK BEHIND IT ACROSS WESTERN
ILLINOIS. THE QUESTION IS HOW FAR EAST THIS PARTIAL CLEARING MOVES
TOWARDS OUR AREA WHILE AT THE SAME TIME SOUTHERN PLAINS CLOUDS
ADVANCE NORTHEAST TOWARD THAT CLEARING PATCH. END RESULT MAY BE
SOME BRIEF AND PARTIAL CLEARING FOR SOME OF THE SOUTHWEST
COUNTIES.

THE LIGHT SNOW THAT HAS BEEN OCCURRING WILL BE CARRIED AS A CHANCE
THROUGHOUT THE NIGHT IN THE SAME AREAS CURRENTLY AFFECTED. STILL
EXPECT NO MORE THAN A LIGHT COVERING OF SNOW AT WORST FOR SOME
AREAS. MAINLY CLOUDY SKY AND FLOW TURNING MORE OFF THE LAKE SHOULD
KEEP MIN TEMPS TO NO LOWER THAN LOWER 20S TONIGHT.

THURSDAY...THE SOUTHERN PLAINS SYSTEM IS DEPICTED BY MOST MODELS
TO WEAKEN AS IT MOVES INTO RIDGE BEHIND CURRENT TROUGH IN OUR
AREA. NET RESULT WILL BE MAINTENANCE OF CLOUD COVER AND LOW THREAT
FOR LIGHT...NON-ACCUMULATING SNOW THURSDAY AFTERNOON. TEMPERATURES
WILL REBOUND LITTLE...CLIMBING NO MORE THAN LOWER 30S IN THE AFTERNOON.

&&

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 240 PM EST WED DEC 17 2014

IN THE WAKE OF THURSDAY TROUGH EXITING THE AREA MODELS SHOW HIGH
PRESSURE BUILDING OVER THE GREAT LAKES AND AIR DRYING OUT
SUGGESTIVE OF DIMINISHED CLOUD COVER. HESITANT TO DELVE TO FAR
INTO PARTLY CLOUDY SKY GIVEN PERSISTENCE OF LOW CLOUD DECKS
WITHOUT MUCH WIND TO SCOUR THEM OUT. MINIMUM TEMPS ON TRACK IN
LOW TO MID 20S AND DIDN`T CHANGE MUCH.

FRIDAY MAY SHOW A FEW PEAKS AT THE SUN WITH NO WEATHER TO SPEAK
OF. THIS SHOULD ALLOW MAX TEMPS TO REACH MID AND UPPER 30S UNDER
LIGHT EAST WIND.

FRIDAY NIGHT INTO SATURDAY MODELS CONTINUE THE TREND OF NEXT
APPROACHING SYSTEM TO REACH NO FURTHER NORTH THAN SOUTHERN INDIANA
WITH PRECIPITATION AND AN OVERCAST SKY FOR OUR AREA.

HIGH PRESSURE WILL ESSENTIALLY REMAIN IN CONTROL FROM FRIDAY NIGHT
INTO MONDAY AFTERNOON. BEYOND THAT TIME FRAME FAIRLY SIGNIFICANT
SYSTEM IS EXPECTED TO MOVE INTO MIDWEST BUT LATEST TRENDS ARE A
BIT WARMER LEANING TO MORE RAIN THAN SNOW. WITH HIGH UNCERTAINTY
AT TIMES WILL KEEP A RAIN SNOW MIX START CONVERTING TO ALL RAIN BY
TUESDAY THEN BACK TO A MIX OR ALL SNOW WEDNESDAY. AGAIN
UNCERTAINTY IS HIGH AND MANY MORE MODEL RUNS SHOULD SORT THIS OUT.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 730 PM EST WED DEC 17 2014

SHEARED UPPER LEVEL SHORT WAVE WILL CONTINUE TO SHIFT EAST OF THE
AREA TO THE EASTERN GREAT LAKES TONIGHT. THIS WILL RESULT IN SOME
SUBTLE VEERING OF LOW LEVEL WINDS TO PROVIDE A FAVORABLE FETCH FOR
SOME VERY LIGHT LAKE EFFECT SNOW SHOWERS OR PERHAPS POCKETS OF
VERY LIGHT PATCHY DRIZZLE/FREEZING DRIZZLE. ANY PRECIP SHOULD BE
QUITE LIGHT GIVEN STRONG MID LEVEL SUBSIDENCE IN WAKE OF DEPARTING
WAVE AND DRY MID LEVEL PROFILES. WHILE PERIODS OF FLURRIES/LIGHTS
SNOW SHOWERS ARE POSSIBLE THROUGH THURSDAY...TIMING REMAINS QUITE
DIFFICULT TO PIN DOWN...AND WITH EXPECTATION OF NO ACCUMULATION OR
NOTABLE VSBY RESTRICTIONS....WILL RUN WITH DRY TAFS FOR THE 00Z
CYCLE. SYNOPTIC SUBSIDENCE WILL KEEP INVERSION HEIGHTS RELATIVELY
CONSISTENT AND THUS WILL MAINTAIN 2-3K FT CIGS THROUGH THE PERIOD.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EST THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...MARSILI
SHORT TERM...TUCEK
LONG TERM...TUCEK
AVIATION...MARSILI


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA








000
FXUS63 KIWX 172016
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
ISSUED BY NATIONAL WEATHER SERVICE INDIANAPOLIS IN
316 PM EST WED DEC 17 2014

.SYNOPSIS...
ISSUED AT 240 PM EST WED DEC 17 2014

MORE NORMAL DECEMBER WEATHER IN PLACE FOR THE MOMENT WITH ONE
TROUGH SWINGING THROUGH THE GREAT LAKES EARLY THIS EVENING WHILE A
TROUGH IN THE SOUTHERN PLAINS WEAKENS AS IT LIFTS INTO INDIANA
THURSDAY BRINGING A SLIGHT CHANCE FOR LIGHT SNOW INTO OUR SOUTHERN COUNTIES.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 240 PM EST WED DEC 17 2014

CURRENT TROUGH SWINGING ACROSS THE GREAT LAKES THIS EVENING IS
SHOWING SOME EROSION IN THE CLOUD DECK BEHIND IT ACROSS WESTERN
ILLINOIS. THE QUESTION IS HOW FAR EAST THIS PARTIAL CLEARING MOVES
TOWARDS OUR AREA WHILE AT THE SAME TIME SOUTHERN PLAINS CLOUDS
ADVANCE NORTHEAST TOWARD THAT CLEARING PATCH. END RESULT MAY BE
SOME BRIEF AND PARTIAL CLEARING FOR SOME OF THE SOUTHWEST
COUNTIES.

THE LIGHT SNOW THAT HAS BEEN OCCURRING WILL BE CARRIED AS A CHANCE
THROUGHOUT THE NIGHT IN THE SAME AREAS CURRENTLY AFFECTED. STILL
EXPECT NO MORE THAN A LIGHT COVERING OF SNOW AT WORST FOR SOME
AREAS. MAINLY CLOUDY SKY AND FLOW TURNING MORE OFF THE LAKE SHOULD
KEEP MIN TEMPS TO NO LOWER THAN LOWER 20S TONIGHT.

THURSDAY...THE SOUTHERN PLAINS SYSTEM IS DEPICTED BY MOST MODELS
TO WEAKEN AS IT MOVES INTO RIDGE BEHIND CURRENT TROUGH IN OUR
AREA. NET RESULT WILL BE MAINTENANCE OF CLOUD COVER AND LOW THREAT
FOR LIGHT...NON-ACCUMULATING SNOW THURSDAY AFTERNOON. TEMPERATURES
WILL REBOUND LITTLE...CLIMBING NO MORE THAN LOWER 30S IN THE AFTERNOON.

&&

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 240 PM EST WED DEC 17 2014

IN THE WAKE OF THURSDAY TROUGH EXITING THE AREA MODELS SHOW HIGH
PRESSURE BUILDING OVER THE GREAT LAKES AND AIR DRYING OUT
SUGGESTIVE OF DIMINISHED CLOUD COVER. HESITANT TO DELVE TO FAR
INTO PARTLY CLOUDY SKY GIVEN PERSISTENCE OF LOW CLOUD DECKS
WITHOUT MUCH WIND TO SCOUR THEM OUT. MINIMUM TEMPS ON TRACK IN
LOW TO MID 20S AND DIDN`T CHANGE MUCH.

FRIDAY MAY SHOW A FEW PEAKS AT THE SUN WITH NO WEATHER TO SPEAK
OF. THIS SHOULD ALLOW MAX TEMPS TO REACH MID AND UPPER 30S UNDER
LIGHT EAST WIND.

FRIDAY NIGHT INTO SATURDAY MODELS CONTINUE THE TREND OF NEXT
APPROACHING SYSTEM TO REACH NO FURTHER NORTH THAN SOUTHERN INDIANA
WITH PRECIPITATION AND AN OVERCAST SKY FOR OUR AREA.

HIGH PRESSURE WILL ESSENTIALLY REMAIN IN CONTROL FROM FRIDAY NIGHT
INTO MONDAY AFTERNOON. BEYOND THAT TIME FRAME FAIRLY SIGNIFICANT
SYSTEM IS EXPECTED TO MOVE INTO MIDWEST BUT LATEST TRENDS ARE A
BIT WARMER LEANING TO MORE RAIN THAN SNOW. WITH HIGH UNCERTAINTY
AT TIMES WILL KEEP A RAIN SNOW MIX START CONVERTING TO ALL RAIN BY
TUESDAY THEN BACK TO A MIX OR ALL SNOW WEDNESDAY. AGAIN
UNCERTAINTY IS HIGH AND MANY MORE MODEL RUNS SHOULD SORT THIS OUT.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 156 PM EST WED DEC 17 2014

MVFR CIGS ARE EXPECTED TO BE FAIRLY STEADY STATE AT BOTH TAF SITES
THROUGH 18Z THURSDAY. SOME LIGHT SNOW MAY CONTINUE AT KFWA OVER
THE NEXT FEW HOURS BEFORE WINDING DOWN AS THE WINDS SUBSIDE THIS EVENING.
WITH WINDS TURNING MORE NORTHWESTERLY BETWEEN 2-4 KFT AGL...KSBN
COULD SEE LIGHT SNOW SHOWERS THIS EVENING...WHICH COULD BRIEFLY
REDUCE VSBYS. THE BEST TIME FRAME FOR THIS WOULD BE 21Z-04Z. P6SM
VSBYS EXPECTED TO PREVAIL OVERNIGHT. OCCASIONALLY GUSTY WINDS OUT
OF THE WNW WILL EVENTUALLY SUBSIDE TO BELOW 8 KTS AFTER 04Z.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...TUCEK
SHORT TERM...TUCEK
LONG TERM...TUCEK
AVIATION...WEBB


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA









000
FXUS63 KIWX 171900
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
ISSUED BY NATIONAL WEATHER SERVICE INDIANAPOLIS IN
200 PM EST WED DEC 17 2014

.SYNOPSIS...
ISSUED AT 424 AM EST WED DEC 17 2014

COLDER CONDITIONS CAN BE EXPECTED TODAY. A FEW AREAS OF LIGHT
SNOW ALONG WITH PATCHY FREEZING DRIZZLE WILL CHANGE TO ALL SNOW
BEFORE ENDING EARLY TODAY. LIGHT LAKE EFFECT SNOW SHOWERS ACROSS
SOUTHERN LOWER MICHIGAN AND FAR NORTHERN INDIANA WILL LINGER
THROUGH TONIGHT WITH LIGHT SNOW ACCUMULATIONS POSSIBLE. HIGHS
TODAY WILL BE ONLY FROM 30 TO 35. LOWS TONIGHT WILL DIP INTO THE
UPPER TEENS TO MID 20S.

&&

.SHORT TERM...(THIS AFTERNOON THROUGH TONIGHT)
ISSUED AT 1253 PM EST WED DEC 17 2014

UPDATED THIS AFTERNOON POPS TO LIKELY FOR LIGHT SNOW THAT HAS
DEVELOPED WITHIN WEAK WAVES IN THE FLOW COMING OFF THE LAKE. SNOW
WILL CREATE A LIGHT COVERING IN MANY AREAS. REMAINING TEMPERATURE
WIND AND CLOUD ELEMENTS UNCHANGED AND ON COURSE THOUGH IT MIGHT BE
A PUSH TO REACH ABOVE 30 DEGREES.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 422 AM EST WED DEC 17 2014

MOST OF THIS LONG TERM PERIOD WILL BE RELATIVELY QUIET WITH A
TRANSITION TO A MORE ACTIVE PATTERN BY END OF PERIOD AND INTO
CHRISTMAS.

LONG TERM PERIOD BEGINS ON THURSDAY WITH A LOW END LAKE ENHANCED
RESPONSE EXPECTED TO SEASONABLY COLD AIR AND SOME WEAK SYNOPTIC
FEATURES. SINGULARLY NOTHING REALLY STANDS OUT FOR LAKE EFFECT OR
SYNOPTIC PCPN BUT COLLECTIVELY THERE MAY BE A WINDOW FOR SOME LIGHT
SNOW SHOWERS OR DRIZZLE/FREEZING DRIZZLE. NAM12 SHOWS ELONGATED MID
LEVEL TROUGH AND AREA OF SHEARED VORTICITY SINKING SOUTHWARD THROUGH
THE LAKES REGION LATE TONIGHT. ASSOCIATED SURFACE TROUGH TO FOLLOW
BUT BECOMES STATIONARY OVER THE WESTERN LAKES AND INTERIOR MICHIGAN
THURSDAY AS DIABATIC HEATING FROM THE WARMER LAKES LEADS TO RESIDUAL
LAKE AGGREGATE TROUGHING. THIS TROUGH TO PROVIDE A CYCLONICALLY
CURVED FETCH DOWN THE LONG AXIS OF LAKE MICHIGAN. DELTA T VALUES WILL
ONLY BE MARGINAL IN THE 11 TO 13C RANGE AND MOISTURE WILL BE
CONFINED TO LOWEST 3KFT. THE DGZ IS NOT EVEN CLOSE TO SATURATED WITH
ONLY THE VERY TOP OF THE SATURATED LAYER NEARING THE -10C THRESHOLD.
WHAT MAKES THIS INTERESTING IS THE POSSIBILITY OF A FEW MESOVORTICES
DEVELOPING WITHIN AXIS OF SURFACE TROUGH NEAR THE LAKESHORE WHERE
DIFFERENTIAL HEATING AND CONVERGENCE WILL BE MAXIMIZED. THESE
PARAMETERS ARE SIMILAR TO THE LOCALLY STUDIED TYPE VI LAKE EFFECT
EVENTS BUT PARAMETERS ARE MUCH WEAKER THAN TYPICALLY EXPECTED.
HOWEVER...A SIMILAR CASE THIS FALL DID PRODUCE SEVERAL VORTICES
WHICH BRIEFLY ENHANCED PCPN NEAR THE LAKESHORE...THOUGH DELTA T
VALUES WERE SLIGHTLY HIGHER. NAM12 IS PICKING UP ON THIS POTENTIAL
WITH A RATHER STRONG 925MB VORTICITY SIGNATURE IN THE EXPECTED
LOCATION. THE LIMITING FACTORS ARE QUITE STRONG BUT BELIEVE THIS
SIGNATURE AND COMBINATION OF FEATURES WARRANT LOW TO MID CHANCE POPS
WITH SCATTERED WORDING. PCPN TYPE REMAINS A QUANDARY GIVEN THE LACK
OF ICE INTRODUCTION. WITH THE SMALL PROBABILITY OF THIS EVENT HAVE
OPTED TO STICK WITH SNOW SHOWERS FOR NOW AND EVALUATE HIGHER RES
GUIDANCE AS TIME NEARS AND SEE IF CONDITIONS COME TOGETHER. ANY SNOW
ACCUMULATIONS WILL BE LIGHT AND GENERALLY AN INCH OR LESS BUT ALSO
CONDITIONAL ON THIS ENHANCED DEVELOPMENT.

A WEAK SHORT WAVE TO PASS BY TO OUR SOUTH LATER THURSDAY WHICH
SHOULD HELP LOCK CLOUDS IN ACROSS THE REGION. WILL KEEP FORECAST DRY
BUT A FEW FLURRIES NOT OUT OF QUESTION. SEVERAL MORE WEAK SHORT
WAVES TO MOVE THROUGH BUT SHOULD STAY DRY THROUGH THE WEEKEND. A
STRONGER SYSTEM TO OUR SOUTH THIS WEEKEND STILL LOOKS TO STAY SOUTH
BUT WILL ALSO HELP TO KEEP SKIES CLOUDY.

THE END OF THIS PERIOD STILL LOOKS TO BE A CHALLENGE WITH A LOT OF
DIFFERENCES AMONG MODELS AND LACK OF CONFIDENCE IN ANY SPECIFIC
OUTCOME. MODELS ARE ALL IN AGREEMENT ON A DECENT STORM SYSTEM MOVING
THROUGH THE MIDWEST NEXT WEEK BUT SPECIFIC AND IMPORTANT DETAILS
VARY SIGNIFICANTLY IN THESE LONGER TIME PERIODS OF DAY 6 TO 9. FOR
NOW HAVE STAYED WITH THE CONSENSUS BLENDS OF MID CHANCE POP CATEGORY
TUESDAY. THERMAL PROFILES ALL OVER THE SPECTRUM BUT ACCUMULATING SNOWFALL
IS PLAUSIBLE BY CHRISTMAS EVE. THOSE WITH TRAVEL PLANS SHOULD STAY
TUNED AND STAY INFORMED AS DETAILS BECOME MORE CLEAR OVER THE NEXT
WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 156 PM EST WED DEC 17 2014

MVFR CIGS ARE EXPECTED TO BE FAIRLY STEADY STATE AT BOTH TAF SITES
THROUGH 18Z THURSDAY. SOME LIGHT SNOW MAY CONTINUE AT KFWA OVER
THE NEXT FEW HOURS BEFORE WINDING DOWN AS THE WINDS SUBSIDE THIS EVENING.
WITH WINDS TURNING MORE NORTHWESTERLY BETWEEN 2-4 KFT AGL...KSBN
COULD SEE LIGHT SNOW SHOWERS THIS EVENING...WHICH COULD BRIEFLY
REDUCE VSBYS. THE BEST TIME FRAME FOR THIS WOULD BE 21Z-04Z. P6SM
VSBYS EXPECTED TO PREVAIL OVERNIGHT. OCCASIONALLY GUSTY WINDS OUT
OF THE WNW WILL EVENTUALLY SUBSIDE TO BELOW 8 KTS AFTER 04Z.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...SKIPPER
SHORT TERM...TUCEK
LONG TERM...LASHLEY
AVIATION...WEBB


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA








000
FXUS63 KIWX 171900
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
ISSUED BY NATIONAL WEATHER SERVICE INDIANAPOLIS IN
200 PM EST WED DEC 17 2014

.SYNOPSIS...
ISSUED AT 424 AM EST WED DEC 17 2014

COLDER CONDITIONS CAN BE EXPECTED TODAY. A FEW AREAS OF LIGHT
SNOW ALONG WITH PATCHY FREEZING DRIZZLE WILL CHANGE TO ALL SNOW
BEFORE ENDING EARLY TODAY. LIGHT LAKE EFFECT SNOW SHOWERS ACROSS
SOUTHERN LOWER MICHIGAN AND FAR NORTHERN INDIANA WILL LINGER
THROUGH TONIGHT WITH LIGHT SNOW ACCUMULATIONS POSSIBLE. HIGHS
TODAY WILL BE ONLY FROM 30 TO 35. LOWS TONIGHT WILL DIP INTO THE
UPPER TEENS TO MID 20S.

&&

.SHORT TERM...(THIS AFTERNOON THROUGH TONIGHT)
ISSUED AT 1253 PM EST WED DEC 17 2014

UPDATED THIS AFTERNOON POPS TO LIKELY FOR LIGHT SNOW THAT HAS
DEVELOPED WITHIN WEAK WAVES IN THE FLOW COMING OFF THE LAKE. SNOW
WILL CREATE A LIGHT COVERING IN MANY AREAS. REMAINING TEMPERATURE
WIND AND CLOUD ELEMENTS UNCHANGED AND ON COURSE THOUGH IT MIGHT BE
A PUSH TO REACH ABOVE 30 DEGREES.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 422 AM EST WED DEC 17 2014

MOST OF THIS LONG TERM PERIOD WILL BE RELATIVELY QUIET WITH A
TRANSITION TO A MORE ACTIVE PATTERN BY END OF PERIOD AND INTO
CHRISTMAS.

LONG TERM PERIOD BEGINS ON THURSDAY WITH A LOW END LAKE ENHANCED
RESPONSE EXPECTED TO SEASONABLY COLD AIR AND SOME WEAK SYNOPTIC
FEATURES. SINGULARLY NOTHING REALLY STANDS OUT FOR LAKE EFFECT OR
SYNOPTIC PCPN BUT COLLECTIVELY THERE MAY BE A WINDOW FOR SOME LIGHT
SNOW SHOWERS OR DRIZZLE/FREEZING DRIZZLE. NAM12 SHOWS ELONGATED MID
LEVEL TROUGH AND AREA OF SHEARED VORTICITY SINKING SOUTHWARD THROUGH
THE LAKES REGION LATE TONIGHT. ASSOCIATED SURFACE TROUGH TO FOLLOW
BUT BECOMES STATIONARY OVER THE WESTERN LAKES AND INTERIOR MICHIGAN
THURSDAY AS DIABATIC HEATING FROM THE WARMER LAKES LEADS TO RESIDUAL
LAKE AGGREGATE TROUGHING. THIS TROUGH TO PROVIDE A CYCLONICALLY
CURVED FETCH DOWN THE LONG AXIS OF LAKE MICHIGAN. DELTA T VALUES WILL
ONLY BE MARGINAL IN THE 11 TO 13C RANGE AND MOISTURE WILL BE
CONFINED TO LOWEST 3KFT. THE DGZ IS NOT EVEN CLOSE TO SATURATED WITH
ONLY THE VERY TOP OF THE SATURATED LAYER NEARING THE -10C THRESHOLD.
WHAT MAKES THIS INTERESTING IS THE POSSIBILITY OF A FEW MESOVORTICES
DEVELOPING WITHIN AXIS OF SURFACE TROUGH NEAR THE LAKESHORE WHERE
DIFFERENTIAL HEATING AND CONVERGENCE WILL BE MAXIMIZED. THESE
PARAMETERS ARE SIMILAR TO THE LOCALLY STUDIED TYPE VI LAKE EFFECT
EVENTS BUT PARAMETERS ARE MUCH WEAKER THAN TYPICALLY EXPECTED.
HOWEVER...A SIMILAR CASE THIS FALL DID PRODUCE SEVERAL VORTICES
WHICH BRIEFLY ENHANCED PCPN NEAR THE LAKESHORE...THOUGH DELTA T
VALUES WERE SLIGHTLY HIGHER. NAM12 IS PICKING UP ON THIS POTENTIAL
WITH A RATHER STRONG 925MB VORTICITY SIGNATURE IN THE EXPECTED
LOCATION. THE LIMITING FACTORS ARE QUITE STRONG BUT BELIEVE THIS
SIGNATURE AND COMBINATION OF FEATURES WARRANT LOW TO MID CHANCE POPS
WITH SCATTERED WORDING. PCPN TYPE REMAINS A QUANDARY GIVEN THE LACK
OF ICE INTRODUCTION. WITH THE SMALL PROBABILITY OF THIS EVENT HAVE
OPTED TO STICK WITH SNOW SHOWERS FOR NOW AND EVALUATE HIGHER RES
GUIDANCE AS TIME NEARS AND SEE IF CONDITIONS COME TOGETHER. ANY SNOW
ACCUMULATIONS WILL BE LIGHT AND GENERALLY AN INCH OR LESS BUT ALSO
CONDITIONAL ON THIS ENHANCED DEVELOPMENT.

A WEAK SHORT WAVE TO PASS BY TO OUR SOUTH LATER THURSDAY WHICH
SHOULD HELP LOCK CLOUDS IN ACROSS THE REGION. WILL KEEP FORECAST DRY
BUT A FEW FLURRIES NOT OUT OF QUESTION. SEVERAL MORE WEAK SHORT
WAVES TO MOVE THROUGH BUT SHOULD STAY DRY THROUGH THE WEEKEND. A
STRONGER SYSTEM TO OUR SOUTH THIS WEEKEND STILL LOOKS TO STAY SOUTH
BUT WILL ALSO HELP TO KEEP SKIES CLOUDY.

THE END OF THIS PERIOD STILL LOOKS TO BE A CHALLENGE WITH A LOT OF
DIFFERENCES AMONG MODELS AND LACK OF CONFIDENCE IN ANY SPECIFIC
OUTCOME. MODELS ARE ALL IN AGREEMENT ON A DECENT STORM SYSTEM MOVING
THROUGH THE MIDWEST NEXT WEEK BUT SPECIFIC AND IMPORTANT DETAILS
VARY SIGNIFICANTLY IN THESE LONGER TIME PERIODS OF DAY 6 TO 9. FOR
NOW HAVE STAYED WITH THE CONSENSUS BLENDS OF MID CHANCE POP CATEGORY
TUESDAY. THERMAL PROFILES ALL OVER THE SPECTRUM BUT ACCUMULATING SNOWFALL
IS PLAUSIBLE BY CHRISTMAS EVE. THOSE WITH TRAVEL PLANS SHOULD STAY
TUNED AND STAY INFORMED AS DETAILS BECOME MORE CLEAR OVER THE NEXT
WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 156 PM EST WED DEC 17 2014

MVFR CIGS ARE EXPECTED TO BE FAIRLY STEADY STATE AT BOTH TAF SITES
THROUGH 18Z THURSDAY. SOME LIGHT SNOW MAY CONTINUE AT KFWA OVER
THE NEXT FEW HOURS BEFORE WINDING DOWN AS THE WINDS SUBSIDE THIS EVENING.
WITH WINDS TURNING MORE NORTHWESTERLY BETWEEN 2-4 KFT AGL...KSBN
COULD SEE LIGHT SNOW SHOWERS THIS EVENING...WHICH COULD BRIEFLY
REDUCE VSBYS. THE BEST TIME FRAME FOR THIS WOULD BE 21Z-04Z. P6SM
VSBYS EXPECTED TO PREVAIL OVERNIGHT. OCCASIONALLY GUSTY WINDS OUT
OF THE WNW WILL EVENTUALLY SUBSIDE TO BELOW 8 KTS AFTER 04Z.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...SKIPPER
SHORT TERM...TUCEK
LONG TERM...LASHLEY
AVIATION...WEBB


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA









000
FXUS63 KIWX 171755
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
ISSUED BY NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1255 PM EST WED DEC 17 2014

.SYNOPSIS...
ISSUED AT 424 AM EST WED DEC 17 2014

COLDER CONDITIONS CAN BE EXPECTED TODAY. A FEW AREAS OF LIGHT
SNOW ALONG WITH PATCHY FREEZING DRIZZLE WILL CHANGE TO ALL SNOW
BEFORE ENDING EARLY TODAY. LIGHT LAKE EFFECT SNOW SHOWERS ACROSS
SOUTHERN LOWER MICHIGAN AND FAR NORTHERN INDIANA WILL LINGER
THROUGH TONIGHT WITH LIGHT SNOW ACCUMULATIONS POSSIBLE. HIGHS
TODAY WILL BE ONLY FROM 30 TO 35. LOWS TONIGHT WILL DIP INTO THE
UPPER TEENS TO MID 20S.

&&

.SHORT TERM...(THIS AFTERNOON THROUGH TONIGHT)
ISSUED AT 1253 PM EST WED DEC 17 2014

UPDATED THIS AFTERNOON POPS TO LIKELY FOR LIGHT SNOW THAT HAS
DEVELOPED WITHIN WEAK WAVES IN THE FLOW COMING OFF THE LAKE. SNOW
WILL CREATE A LIGHT COVERING IN MANY AREAS. REMAINING TEMPERATURE
WIND AND CLOUD ELEMENTS UNCHANGED AND ON COURSE THOUGH IT MIGHT BE
A PUSH TO REACH ABOVE 30 DEGREES.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 422 AM EST WED DEC 17 2014

MOST OF THIS LONG TERM PERIOD WILL BE RELATIVELY QUIET WITH A
TRANSITION TO A MORE ACTIVE PATTERN BY END OF PERIOD AND INTO
CHRISTMAS.

LONG TERM PERIOD BEGINS ON THURSDAY WITH A LOW END LAKE ENHANCED
RESPONSE EXPECTED TO SEASONABLY COLD AIR AND SOME WEAK SYNOPTIC
FEATURES. SINGULARLY NOTHING REALLY STANDS OUT FOR LAKE EFFECT OR
SYNOPTIC PCPN BUT COLLECTIVELY THERE MAY BE A WINDOW FOR SOME LIGHT
SNOW SHOWERS OR DRIZZLE/FREEZING DRIZZLE. NAM12 SHOWS ELONGATED MID
LEVEL TROUGH AND AREA OF SHEARED VORTICITY SINKING SOUTHWARD THROUGH
THE LAKES REGION LATE TONIGHT. ASSOCIATED SURFACE TROUGH TO FOLLOW
BUT BECOMES STATIONARY OVER THE WESTERN LAKES AND INTERIOR MICHIGAN
THURSDAY AS DIABATIC HEATING FROM THE WARMER LAKES LEADS TO RESIDUAL
LAKE AGGREGATE TROUGHING. THIS TROUGH TO PROVIDE A CYCLONICALLY
CURVED FETCH DOWN THE LONG AXIS OF LAKE MICHIGAN. DELTA T VALUES WILL
ONLY BE MARGINAL IN THE 11 TO 13C RANGE AND MOISTURE WILL BE
CONFINED TO LOWEST 3KFT. THE DGZ IS NOT EVEN CLOSE TO SATURATED WITH
ONLY THE VERY TOP OF THE SATURATED LAYER NEARING THE -10C THRESHOLD.
WHAT MAKES THIS INTERESTING IS THE POSSIBILITY OF A FEW MESOVORTICES
DEVELOPING WITHIN AXIS OF SURFACE TROUGH NEAR THE LAKESHORE WHERE
DIFFERENTIAL HEATING AND CONVERGENCE WILL BE MAXIMIZED. THESE
PARAMETERS ARE SIMILAR TO THE LOCALLY STUDIED TYPE VI LAKE EFFECT
EVENTS BUT PARAMETERS ARE MUCH WEAKER THAN TYPICALLY EXPECTED.
HOWEVER...A SIMILAR CASE THIS FALL DID PRODUCE SEVERAL VORTICES
WHICH BRIEFLY ENHANCED PCPN NEAR THE LAKESHORE...THOUGH DELTA T
VALUES WERE SLIGHTLY HIGHER. NAM12 IS PICKING UP ON THIS POTENTIAL
WITH A RATHER STRONG 925MB VORTICITY SIGNATURE IN THE EXPECTED
LOCATION. THE LIMITING FACTORS ARE QUITE STRONG BUT BELIEVE THIS
SIGNATURE AND COMBINATION OF FEATURES WARRANT LOW TO MID CHANCE POPS
WITH SCATTERED WORDING. PCPN TYPE REMAINS A QUANDARY GIVEN THE LACK
OF ICE INTRODUCTION. WITH THE SMALL PROBABILITY OF THIS EVENT HAVE
OPTED TO STICK WITH SNOW SHOWERS FOR NOW AND EVALUATE HIGHER RES
GUIDANCE AS TIME NEARS AND SEE IF CONDITIONS COME TOGETHER. ANY SNOW
ACCUMULATIONS WILL BE LIGHT AND GENERALLY AN INCH OR LESS BUT ALSO
CONDITIONAL ON THIS ENHANCED DEVELOPMENT.

A WEAK SHORT WAVE TO PASS BY TO OUR SOUTH LATER THURSDAY WHICH
SHOULD HELP LOCK CLOUDS IN ACROSS THE REGION. WILL KEEP FORECAST DRY
BUT A FEW FLURRIES NOT OUT OF QUESTION. SEVERAL MORE WEAK SHORT
WAVES TO MOVE THROUGH BUT SHOULD STAY DRY THROUGH THE WEEKEND. A
STRONGER SYSTEM TO OUR SOUTH THIS WEEKEND STILL LOOKS TO STAY SOUTH
BUT WILL ALSO HELP TO KEEP SKIES CLOUDY.

THE END OF THIS PERIOD STILL LOOKS TO BE A CHALLENGE WITH A LOT OF
DIFFERENCES AMONG MODELS AND LACK OF CONFIDENCE IN ANY SPECIFIC
OUTCOME. MODELS ARE ALL IN AGREEMENT ON A DECENT STORM SYSTEM MOVING
THROUGH THE MIDWEST NEXT WEEK BUT SPECIFIC AND IMPORTANT DETAILS
VARY SIGNIFICANTLY IN THESE LONGER TIME PERIODS OF DAY 6 TO 9. FOR
NOW HAVE STAYED WITH THE CONSENSUS BLENDS OF MID CHANCE POP CATEGORY
TUESDAY. THERMAL PROFILES ALL OVER THE SPECTRUM BUT ACCUMULATING SNOWFALL
IS PLAUSIBLE BY CHRISTMAS EVE. THOSE WITH TRAVEL PLANS SHOULD STAY
TUNED AND STAY INFORMED AS DETAILS BECOME MORE CLEAR OVER THE NEXT
WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 549 AM EST WED DEC 17 2014

COLD AIR ADVECTION WILL CONTINUE TODAY. DRIER AIR WAS SPREADING
ACROSS NORTHERN INDIANA...SO EXPECT CLOUDY CONDITIONS WITH LAKE
EFFECT SNOW SHOWERS REMAINING MAINLY NORTHWEST AND NORTH OF SBN.
MVFR CIGS SHOULD IMPROVE BY LATE IN THE TAF PERIOD. WENT
OPTIMISTIC WITH VFR CONDITIONS AT BOTH SITES BY 00Z.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...SKIPPER
SHORT TERM...TUCEK
LONG TERM...LASHLEY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA







000
FXUS63 KIWX 171755
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
ISSUED BY NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1255 PM EST WED DEC 17 2014

.SYNOPSIS...
ISSUED AT 424 AM EST WED DEC 17 2014

COLDER CONDITIONS CAN BE EXPECTED TODAY. A FEW AREAS OF LIGHT
SNOW ALONG WITH PATCHY FREEZING DRIZZLE WILL CHANGE TO ALL SNOW
BEFORE ENDING EARLY TODAY. LIGHT LAKE EFFECT SNOW SHOWERS ACROSS
SOUTHERN LOWER MICHIGAN AND FAR NORTHERN INDIANA WILL LINGER
THROUGH TONIGHT WITH LIGHT SNOW ACCUMULATIONS POSSIBLE. HIGHS
TODAY WILL BE ONLY FROM 30 TO 35. LOWS TONIGHT WILL DIP INTO THE
UPPER TEENS TO MID 20S.

&&

.SHORT TERM...(THIS AFTERNOON THROUGH TONIGHT)
ISSUED AT 1253 PM EST WED DEC 17 2014

UPDATED THIS AFTERNOON POPS TO LIKELY FOR LIGHT SNOW THAT HAS
DEVELOPED WITHIN WEAK WAVES IN THE FLOW COMING OFF THE LAKE. SNOW
WILL CREATE A LIGHT COVERING IN MANY AREAS. REMAINING TEMPERATURE
WIND AND CLOUD ELEMENTS UNCHANGED AND ON COURSE THOUGH IT MIGHT BE
A PUSH TO REACH ABOVE 30 DEGREES.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 422 AM EST WED DEC 17 2014

MOST OF THIS LONG TERM PERIOD WILL BE RELATIVELY QUIET WITH A
TRANSITION TO A MORE ACTIVE PATTERN BY END OF PERIOD AND INTO
CHRISTMAS.

LONG TERM PERIOD BEGINS ON THURSDAY WITH A LOW END LAKE ENHANCED
RESPONSE EXPECTED TO SEASONABLY COLD AIR AND SOME WEAK SYNOPTIC
FEATURES. SINGULARLY NOTHING REALLY STANDS OUT FOR LAKE EFFECT OR
SYNOPTIC PCPN BUT COLLECTIVELY THERE MAY BE A WINDOW FOR SOME LIGHT
SNOW SHOWERS OR DRIZZLE/FREEZING DRIZZLE. NAM12 SHOWS ELONGATED MID
LEVEL TROUGH AND AREA OF SHEARED VORTICITY SINKING SOUTHWARD THROUGH
THE LAKES REGION LATE TONIGHT. ASSOCIATED SURFACE TROUGH TO FOLLOW
BUT BECOMES STATIONARY OVER THE WESTERN LAKES AND INTERIOR MICHIGAN
THURSDAY AS DIABATIC HEATING FROM THE WARMER LAKES LEADS TO RESIDUAL
LAKE AGGREGATE TROUGHING. THIS TROUGH TO PROVIDE A CYCLONICALLY
CURVED FETCH DOWN THE LONG AXIS OF LAKE MICHIGAN. DELTA T VALUES WILL
ONLY BE MARGINAL IN THE 11 TO 13C RANGE AND MOISTURE WILL BE
CONFINED TO LOWEST 3KFT. THE DGZ IS NOT EVEN CLOSE TO SATURATED WITH
ONLY THE VERY TOP OF THE SATURATED LAYER NEARING THE -10C THRESHOLD.
WHAT MAKES THIS INTERESTING IS THE POSSIBILITY OF A FEW MESOVORTICES
DEVELOPING WITHIN AXIS OF SURFACE TROUGH NEAR THE LAKESHORE WHERE
DIFFERENTIAL HEATING AND CONVERGENCE WILL BE MAXIMIZED. THESE
PARAMETERS ARE SIMILAR TO THE LOCALLY STUDIED TYPE VI LAKE EFFECT
EVENTS BUT PARAMETERS ARE MUCH WEAKER THAN TYPICALLY EXPECTED.
HOWEVER...A SIMILAR CASE THIS FALL DID PRODUCE SEVERAL VORTICES
WHICH BRIEFLY ENHANCED PCPN NEAR THE LAKESHORE...THOUGH DELTA T
VALUES WERE SLIGHTLY HIGHER. NAM12 IS PICKING UP ON THIS POTENTIAL
WITH A RATHER STRONG 925MB VORTICITY SIGNATURE IN THE EXPECTED
LOCATION. THE LIMITING FACTORS ARE QUITE STRONG BUT BELIEVE THIS
SIGNATURE AND COMBINATION OF FEATURES WARRANT LOW TO MID CHANCE POPS
WITH SCATTERED WORDING. PCPN TYPE REMAINS A QUANDARY GIVEN THE LACK
OF ICE INTRODUCTION. WITH THE SMALL PROBABILITY OF THIS EVENT HAVE
OPTED TO STICK WITH SNOW SHOWERS FOR NOW AND EVALUATE HIGHER RES
GUIDANCE AS TIME NEARS AND SEE IF CONDITIONS COME TOGETHER. ANY SNOW
ACCUMULATIONS WILL BE LIGHT AND GENERALLY AN INCH OR LESS BUT ALSO
CONDITIONAL ON THIS ENHANCED DEVELOPMENT.

A WEAK SHORT WAVE TO PASS BY TO OUR SOUTH LATER THURSDAY WHICH
SHOULD HELP LOCK CLOUDS IN ACROSS THE REGION. WILL KEEP FORECAST DRY
BUT A FEW FLURRIES NOT OUT OF QUESTION. SEVERAL MORE WEAK SHORT
WAVES TO MOVE THROUGH BUT SHOULD STAY DRY THROUGH THE WEEKEND. A
STRONGER SYSTEM TO OUR SOUTH THIS WEEKEND STILL LOOKS TO STAY SOUTH
BUT WILL ALSO HELP TO KEEP SKIES CLOUDY.

THE END OF THIS PERIOD STILL LOOKS TO BE A CHALLENGE WITH A LOT OF
DIFFERENCES AMONG MODELS AND LACK OF CONFIDENCE IN ANY SPECIFIC
OUTCOME. MODELS ARE ALL IN AGREEMENT ON A DECENT STORM SYSTEM MOVING
THROUGH THE MIDWEST NEXT WEEK BUT SPECIFIC AND IMPORTANT DETAILS
VARY SIGNIFICANTLY IN THESE LONGER TIME PERIODS OF DAY 6 TO 9. FOR
NOW HAVE STAYED WITH THE CONSENSUS BLENDS OF MID CHANCE POP CATEGORY
TUESDAY. THERMAL PROFILES ALL OVER THE SPECTRUM BUT ACCUMULATING SNOWFALL
IS PLAUSIBLE BY CHRISTMAS EVE. THOSE WITH TRAVEL PLANS SHOULD STAY
TUNED AND STAY INFORMED AS DETAILS BECOME MORE CLEAR OVER THE NEXT
WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 549 AM EST WED DEC 17 2014

COLD AIR ADVECTION WILL CONTINUE TODAY. DRIER AIR WAS SPREADING
ACROSS NORTHERN INDIANA...SO EXPECT CLOUDY CONDITIONS WITH LAKE
EFFECT SNOW SHOWERS REMAINING MAINLY NORTHWEST AND NORTH OF SBN.
MVFR CIGS SHOULD IMPROVE BY LATE IN THE TAF PERIOD. WENT
OPTIMISTIC WITH VFR CONDITIONS AT BOTH SITES BY 00Z.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...SKIPPER
SHORT TERM...TUCEK
LONG TERM...LASHLEY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA








000
FXUS63 KIWX 171653
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
ISSUED BY NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1153 AM EST WED DEC 17 2014

.SYNOPSIS...
ISSUED AT 424 AM EST WED DEC 17 2014

COLDER CONDITIONS CAN BE EXPECTED TODAY. A FEW AREAS OF LIGHT
SNOW ALONG WITH PATCHY FREEZING DRIZZLE WILL CHANGE TO ALL SNOW
BEFORE ENDING EARLY TODAY. LIGHT LAKE EFFECT SNOW SHOWERS ACROSS
SOUTHERN LOWER MICHIGAN AND FAR NORTHERN INDIANA WILL LINGER
THROUGH TONIGHT WITH LIGHT SNOW ACCUMULATIONS POSSIBLE. HIGHS
TODAY WILL BE ONLY FROM 30 TO 35. LOWS TONIGHT WILL DIP INTO THE
UPPER TEENS TO MID 20S.

&&

.SHORT TERM...(THIS AFTERNOON AND TONIGHT)
ISSUED AT 1150 AM EST WED DEC 17 2014

UPDATED THIS AFTERNOON TO INCLUDE VERY LIGHT SNOW THAT HAS
DEVELOPED WITHIN WEAK WAVES IN THE FLOW COMING OFF THE LAKE. MAY
CREATE A LIGHT DUSTING IN SOME AREAS. REMAINING TEMPERATURE WIND
AND CLOUD ELEMENTS UNCHANGED AND ON COURSE THOUGH IT MIGHT BE A
PUSH TO REACH ABOVE 30 DEGREES.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 422 AM EST WED DEC 17 2014

MOST OF THIS LONG TERM PERIOD WILL BE RELATIVELY QUIET WITH A
TRANSITION TO A MORE ACTIVE PATTERN BY END OF PERIOD AND INTO
CHRISTMAS.

LONG TERM PERIOD BEGINS ON THURSDAY WITH A LOW END LAKE ENHANCED
RESPONSE EXPECTED TO SEASONABLY COLD AIR AND SOME WEAK SYNOPTIC
FEATURES. SINGULARLY NOTHING REALLY STANDS OUT FOR LAKE EFFECT OR
SYNOPTIC PCPN BUT COLLECTIVELY THERE MAY BE A WINDOW FOR SOME LIGHT
SNOW SHOWERS OR DRIZZLE/FREEZING DRIZZLE. NAM12 SHOWS ELONGATED MID
LEVEL TROUGH AND AREA OF SHEARED VORTICITY SINKING SOUTHWARD THROUGH
THE LAKES REGION LATE TONIGHT. ASSOCIATED SURFACE TROUGH TO FOLLOW
BUT BECOMES STATIONARY OVER THE WESTERN LAKES AND INTERIOR MICHIGAN
THURSDAY AS DIABATIC HEATING FROM THE WARMER LAKES LEADS TO RESIDUAL
LAKE AGGREGATE TROUGHING. THIS TROUGH TO PROVIDE A CYCLONICALLY
CURVED FETCH DOWN THE LONG AXIS OF LAKE MICHIGAN. DELTA T VALUES WILL
ONLY BE MARGINAL IN THE 11 TO 13C RANGE AND MOISTURE WILL BE
CONFINED TO LOWEST 3KFT. THE DGZ IS NOT EVEN CLOSE TO SATURATED WITH
ONLY THE VERY TOP OF THE SATURATED LAYER NEARING THE -10C THRESHOLD.
WHAT MAKES THIS INTERESTING IS THE POSSIBILITY OF A FEW MESOVORTICES
DEVELOPING WITHIN AXIS OF SURFACE TROUGH NEAR THE LAKESHORE WHERE
DIFFERENTIAL HEATING AND CONVERGENCE WILL BE MAXIMIZED. THESE
PARAMETERS ARE SIMILAR TO THE LOCALLY STUDIED TYPE VI LAKE EFFECT
EVENTS BUT PARAMETERS ARE MUCH WEAKER THAN TYPICALLY EXPECTED.
HOWEVER...A SIMILAR CASE THIS FALL DID PRODUCE SEVERAL VORTICES
WHICH BRIEFLY ENHANCED PCPN NEAR THE LAKESHORE...THOUGH DELTA T
VALUES WERE SLIGHTLY HIGHER. NAM12 IS PICKING UP ON THIS POTENTIAL
WITH A RATHER STRONG 925MB VORTICITY SIGNATURE IN THE EXPECTED
LOCATION. THE LIMITING FACTORS ARE QUITE STRONG BUT BELIEVE THIS
SIGNATURE AND COMBINATION OF FEATURES WARRANT LOW TO MID CHANCE POPS
WITH SCATTERED WORDING. PCPN TYPE REMAINS A QUANDARY GIVEN THE LACK
OF ICE INTRODUCTION. WITH THE SMALL PROBABILITY OF THIS EVENT HAVE
OPTED TO STICK WITH SNOW SHOWERS FOR NOW AND EVALUATE HIGHER RES
GUIDANCE AS TIME NEARS AND SEE IF CONDITIONS COME TOGETHER. ANY SNOW
ACCUMULATIONS WILL BE LIGHT AND GENERALLY AN INCH OR LESS BUT ALSO
CONDITIONAL ON THIS ENHANCED DEVELOPMENT.

A WEAK SHORT WAVE TO PASS BY TO OUR SOUTH LATER THURSDAY WHICH
SHOULD HELP LOCK CLOUDS IN ACROSS THE REGION. WILL KEEP FORECAST DRY
BUT A FEW FLURRIES NOT OUT OF QUESTION. SEVERAL MORE WEAK SHORT
WAVES TO MOVE THROUGH BUT SHOULD STAY DRY THROUGH THE WEEKEND. A
STRONGER SYSTEM TO OUR SOUTH THIS WEEKEND STILL LOOKS TO STAY SOUTH
BUT WILL ALSO HELP TO KEEP SKIES CLOUDY.

THE END OF THIS PERIOD STILL LOOKS TO BE A CHALLENGE WITH A LOT OF
DIFFERENCES AMONG MODELS AND LACK OF CONFIDENCE IN ANY SPECIFIC
OUTCOME. MODELS ARE ALL IN AGREEMENT ON A DECENT STORM SYSTEM MOVING
THROUGH THE MIDWEST NEXT WEEK BUT SPECIFIC AND IMPORTANT DETAILS
VARY SIGNIFICANTLY IN THESE LONGER TIME PERIODS OF DAY 6 TO 9. FOR
NOW HAVE STAYED WITH THE CONSENSUS BLENDS OF MID CHANCE POP CATEGORY
TUESDAY. THERMAL PROFILES ALL OVER THE SPECTRUM BUT ACCUMULATING SNOWFALL
IS PLAUSIBLE BY CHRISTMAS EVE. THOSE WITH TRAVEL PLANS SHOULD STAY
TUNED AND STAY INFORMED AS DETAILS BECOME MORE CLEAR OVER THE NEXT
WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 549 AM EST WED DEC 17 2014

COLD AIR ADVECTION WILL CONTINUE TODAY. DRIER AIR WAS SPREADING
ACROSS NORTHERN INDIANA...SO EXPECT CLOUDY CONDITIONS WITH LAKE
EFFECT SNOW SHOWERS REMAINING MAINLY NORTHWEST AND NORTH OF SBN.
MVFR CIGS SHOULD IMPROVE BY LATE IN THE TAF PERIOD. WENT
OPTIMISTIC WITH VFR CONDITIONS AT BOTH SITES BY 00Z.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...SKIPPER
SHORT TERM...TUCEK
LONG TERM...LASHLEY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA







000
FXUS63 KIWX 171653
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
ISSUED BY NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1153 AM EST WED DEC 17 2014

.SYNOPSIS...
ISSUED AT 424 AM EST WED DEC 17 2014

COLDER CONDITIONS CAN BE EXPECTED TODAY. A FEW AREAS OF LIGHT
SNOW ALONG WITH PATCHY FREEZING DRIZZLE WILL CHANGE TO ALL SNOW
BEFORE ENDING EARLY TODAY. LIGHT LAKE EFFECT SNOW SHOWERS ACROSS
SOUTHERN LOWER MICHIGAN AND FAR NORTHERN INDIANA WILL LINGER
THROUGH TONIGHT WITH LIGHT SNOW ACCUMULATIONS POSSIBLE. HIGHS
TODAY WILL BE ONLY FROM 30 TO 35. LOWS TONIGHT WILL DIP INTO THE
UPPER TEENS TO MID 20S.

&&

.SHORT TERM...(THIS AFTERNOON AND TONIGHT)
ISSUED AT 1150 AM EST WED DEC 17 2014

UPDATED THIS AFTERNOON TO INCLUDE VERY LIGHT SNOW THAT HAS
DEVELOPED WITHIN WEAK WAVES IN THE FLOW COMING OFF THE LAKE. MAY
CREATE A LIGHT DUSTING IN SOME AREAS. REMAINING TEMPERATURE WIND
AND CLOUD ELEMENTS UNCHANGED AND ON COURSE THOUGH IT MIGHT BE A
PUSH TO REACH ABOVE 30 DEGREES.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 422 AM EST WED DEC 17 2014

MOST OF THIS LONG TERM PERIOD WILL BE RELATIVELY QUIET WITH A
TRANSITION TO A MORE ACTIVE PATTERN BY END OF PERIOD AND INTO
CHRISTMAS.

LONG TERM PERIOD BEGINS ON THURSDAY WITH A LOW END LAKE ENHANCED
RESPONSE EXPECTED TO SEASONABLY COLD AIR AND SOME WEAK SYNOPTIC
FEATURES. SINGULARLY NOTHING REALLY STANDS OUT FOR LAKE EFFECT OR
SYNOPTIC PCPN BUT COLLECTIVELY THERE MAY BE A WINDOW FOR SOME LIGHT
SNOW SHOWERS OR DRIZZLE/FREEZING DRIZZLE. NAM12 SHOWS ELONGATED MID
LEVEL TROUGH AND AREA OF SHEARED VORTICITY SINKING SOUTHWARD THROUGH
THE LAKES REGION LATE TONIGHT. ASSOCIATED SURFACE TROUGH TO FOLLOW
BUT BECOMES STATIONARY OVER THE WESTERN LAKES AND INTERIOR MICHIGAN
THURSDAY AS DIABATIC HEATING FROM THE WARMER LAKES LEADS TO RESIDUAL
LAKE AGGREGATE TROUGHING. THIS TROUGH TO PROVIDE A CYCLONICALLY
CURVED FETCH DOWN THE LONG AXIS OF LAKE MICHIGAN. DELTA T VALUES WILL
ONLY BE MARGINAL IN THE 11 TO 13C RANGE AND MOISTURE WILL BE
CONFINED TO LOWEST 3KFT. THE DGZ IS NOT EVEN CLOSE TO SATURATED WITH
ONLY THE VERY TOP OF THE SATURATED LAYER NEARING THE -10C THRESHOLD.
WHAT MAKES THIS INTERESTING IS THE POSSIBILITY OF A FEW MESOVORTICES
DEVELOPING WITHIN AXIS OF SURFACE TROUGH NEAR THE LAKESHORE WHERE
DIFFERENTIAL HEATING AND CONVERGENCE WILL BE MAXIMIZED. THESE
PARAMETERS ARE SIMILAR TO THE LOCALLY STUDIED TYPE VI LAKE EFFECT
EVENTS BUT PARAMETERS ARE MUCH WEAKER THAN TYPICALLY EXPECTED.
HOWEVER...A SIMILAR CASE THIS FALL DID PRODUCE SEVERAL VORTICES
WHICH BRIEFLY ENHANCED PCPN NEAR THE LAKESHORE...THOUGH DELTA T
VALUES WERE SLIGHTLY HIGHER. NAM12 IS PICKING UP ON THIS POTENTIAL
WITH A RATHER STRONG 925MB VORTICITY SIGNATURE IN THE EXPECTED
LOCATION. THE LIMITING FACTORS ARE QUITE STRONG BUT BELIEVE THIS
SIGNATURE AND COMBINATION OF FEATURES WARRANT LOW TO MID CHANCE POPS
WITH SCATTERED WORDING. PCPN TYPE REMAINS A QUANDARY GIVEN THE LACK
OF ICE INTRODUCTION. WITH THE SMALL PROBABILITY OF THIS EVENT HAVE
OPTED TO STICK WITH SNOW SHOWERS FOR NOW AND EVALUATE HIGHER RES
GUIDANCE AS TIME NEARS AND SEE IF CONDITIONS COME TOGETHER. ANY SNOW
ACCUMULATIONS WILL BE LIGHT AND GENERALLY AN INCH OR LESS BUT ALSO
CONDITIONAL ON THIS ENHANCED DEVELOPMENT.

A WEAK SHORT WAVE TO PASS BY TO OUR SOUTH LATER THURSDAY WHICH
SHOULD HELP LOCK CLOUDS IN ACROSS THE REGION. WILL KEEP FORECAST DRY
BUT A FEW FLURRIES NOT OUT OF QUESTION. SEVERAL MORE WEAK SHORT
WAVES TO MOVE THROUGH BUT SHOULD STAY DRY THROUGH THE WEEKEND. A
STRONGER SYSTEM TO OUR SOUTH THIS WEEKEND STILL LOOKS TO STAY SOUTH
BUT WILL ALSO HELP TO KEEP SKIES CLOUDY.

THE END OF THIS PERIOD STILL LOOKS TO BE A CHALLENGE WITH A LOT OF
DIFFERENCES AMONG MODELS AND LACK OF CONFIDENCE IN ANY SPECIFIC
OUTCOME. MODELS ARE ALL IN AGREEMENT ON A DECENT STORM SYSTEM MOVING
THROUGH THE MIDWEST NEXT WEEK BUT SPECIFIC AND IMPORTANT DETAILS
VARY SIGNIFICANTLY IN THESE LONGER TIME PERIODS OF DAY 6 TO 9. FOR
NOW HAVE STAYED WITH THE CONSENSUS BLENDS OF MID CHANCE POP CATEGORY
TUESDAY. THERMAL PROFILES ALL OVER THE SPECTRUM BUT ACCUMULATING SNOWFALL
IS PLAUSIBLE BY CHRISTMAS EVE. THOSE WITH TRAVEL PLANS SHOULD STAY
TUNED AND STAY INFORMED AS DETAILS BECOME MORE CLEAR OVER THE NEXT
WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 549 AM EST WED DEC 17 2014

COLD AIR ADVECTION WILL CONTINUE TODAY. DRIER AIR WAS SPREADING
ACROSS NORTHERN INDIANA...SO EXPECT CLOUDY CONDITIONS WITH LAKE
EFFECT SNOW SHOWERS REMAINING MAINLY NORTHWEST AND NORTH OF SBN.
MVFR CIGS SHOULD IMPROVE BY LATE IN THE TAF PERIOD. WENT
OPTIMISTIC WITH VFR CONDITIONS AT BOTH SITES BY 00Z.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...SKIPPER
SHORT TERM...TUCEK
LONG TERM...LASHLEY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA








000
FXUS63 KIWX 171241
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
ISSUED BY NATIONAL WEATHER SERVICE INDIANAPOLIS IN
741 AM EST WED DEC 17 2014

.SYNOPSIS...
ISSUED AT 424 AM EST WED DEC 17 2014

COLDER CONDITIONS CAN BE EXPECTED TODAY. A FEW AREAS OF LIGHT
SNOW ALONG WITH PATCHY FREEZING DRIZZLE WILL CHANGE TO ALL SNOW
BEFORE ENDING EARLY TODAY. LIGHT LAKE EFFECT SNOW SHOWERS ACROSS
SOUTHERN LOWER MICHIGAN AND FAR NORTHERN INDIANA WILL LINGER
THROUGH TONIGHT WITH LIGHT SNOW ACCUMULATIONS POSSIBLE. HIGHS
TODAY WILL BE ONLY FROM 30 TO 35. LOWS TONIGHT WILL DIP INTO THE
UPPER TEENS TO MID 20S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 735 AM EST WED DEC 17 2014

NO SIGNIFICANT CHANGES MADE OTHER THAN REMOVAL OF PRE DAWN DATA AS
IT APPEARS LIGHT POST FRONTAL PRECIPITATION HAS ENDED. STILL
REMAINS A LOW THREAT FOR PRECIPITATION OFF THE LAKE BUT PRIMARILY
CONFINED TO LOCATIONS IN MICHIGAN OR NEARBY.

PREVIOUS DISCUSSION ISSUED AT 422 AM EST WED DEC 17 2014...

LIGHT POST FRONTAL PRECIPITATION HAD FORMED IN THE AREA OF COLD AIR
ADVECTION OVERNIGHT. NCEP MODELS WERE NOT HANDLING THIS LIGHT
PRECIPITATION VERY WELL. DEEPER LIFT HAD DIMINISHED...SO ONLY LIGHT
PRECIPITATION IS EXPECTED. HOWEVER... WHERE THE DENDRITIC GROWTH
ZONE WAS ABOVE THE CLOUD LAYER...PATCHY FREEZING DRIZZLE WAS BEING
REPORTED. COLD AIR ADVECTION EARLY THIS MORNING SHOULD HELP DEEPEN
THE COLD LAYER AND HELP TURN ANY REMAINING PRECIPITATION TO JUST
SNOW. FOR NOW...DUE TO THE PATCHY AND BRIEF NATURE OF THE FREEZING
DRIZZLE...HAVE ISSUED A SPECIAL WEATHER STATEMENT FOR NORTHERN
INDIANA AND NW OHIO. OTHERWISE...LIGHT LAKE EFFECT SNOW SHOWERS
SHOULD PERSIST. GIVEN DELTA T VALUES RISING TO AROUND 11C AND
RELATIVELY LOW INVERSION HEIGHTS...MINOR SNOW ACCUMULATIONS OVER THE
FAR SOUTHWEST CORNER OF LOWER MICHIGAN INTO ADJACENT AREAS OF
NORTHWEST INDIANA ARE POSSIBLE TODAY AND TONIGHT.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 422 AM EST WED DEC 17 2014

MOST OF THIS LONG TERM PERIOD WILL BE RELATIVELY QUIET WITH A
TRANSITION TO A MORE ACTIVE PATTERN BY END OF PERIOD AND INTO
CHRISTMAS.

LONG TERM PERIOD BEGINS ON THURSDAY WITH A LOW END LAKE ENHANCED
RESPONSE EXPECTED TO SEASONABLY COLD AIR AND SOME WEAK SYNOPTIC
FEATURES. SINGULARLY NOTHING REALLY STANDS OUT FOR LAKE EFFECT OR
SYNOPTIC PCPN BUT COLLECTIVELY THERE MAY BE A WINDOW FOR SOME LIGHT
SNOW SHOWERS OR DRIZZLE/FREEZING DRIZZLE. NAM12 SHOWS ELONGATED MID
LEVEL TROUGH AND AREA OF SHEARED VORTICITY SINKING SOUTHWARD THROUGH
THE LAKES REGION LATE TONIGHT. ASSOCIATED SURFACE TROUGH TO FOLLOW
BUT BECOMES STATIONARY OVER THE WESTERN LAKES AND INTERIOR MICHIGAN
THURSDAY AS DIABATIC HEATING FROM THE WARMER LAKES LEADS TO RESIDUAL
LAKE AGGREGATE TROUGHING. THIS TROUGH TO PROVIDE A CYCLONICALLY
CURVED FETCH DOWN THE LONG AXIS OF LAKE MICHIGAN. DELTA T VALUES WILL
ONLY BE MARGINAL IN THE 11 TO 13C RANGE AND MOISTURE WILL BE
CONFINED TO LOWEST 3KFT. THE DGZ IS NOT EVEN CLOSE TO SATURATED WITH
ONLY THE VERY TOP OF THE SATURATED LAYER NEARING THE -10C THRESHOLD.
WHAT MAKES THIS INTERESTING IS THE POSSIBILITY OF A FEW MESOVORTICES
DEVELOPING WITHIN AXIS OF SURFACE TROUGH NEAR THE LAKESHORE WHERE
DIFFERENTIAL HEATING AND CONVERGENCE WILL BE MAXIMIZED. THESE
PARAMETERS ARE SIMILAR TO THE LOCALLY STUDIED TYPE VI LAKE EFFECT
EVENTS BUT PARAMETERS ARE MUCH WEAKER THAN TYPICALLY EXPECTED.
HOWEVER...A SIMILAR CASE THIS FALL DID PRODUCE SEVERAL VORTICES
WHICH BRIEFLY ENHANCED PCPN NEAR THE LAKESHORE...THOUGH DELTA T
VALUES WERE SLIGHTLY HIGHER. NAM12 IS PICKING UP ON THIS POTENTIAL
WITH A RATHER STRONG 925MB VORTICITY SIGNATURE IN THE EXPECTED
LOCATION. THE LIMITING FACTORS ARE QUITE STRONG BUT BELIEVE THIS
SIGNATURE AND COMBINATION OF FEATURES WARRANT LOW TO MID CHANCE POPS
WITH SCATTERED WORDING. PCPN TYPE REMAINS A QUANDARY GIVEN THE LACK
OF ICE INTRODUCTION. WITH THE SMALL PROBABILITY OF THIS EVENT HAVE
OPTED TO STICK WITH SNOW SHOWERS FOR NOW AND EVALUATE HIGHER RES
GUIDANCE AS TIME NEARS AND SEE IF CONDITIONS COME TOGETHER. ANY SNOW
ACCUMULATIONS WILL BE LIGHT AND GENERALLY AN INCH OR LESS BUT ALSO
CONDITIONAL ON THIS ENHANCED DEVELOPMENT.

A WEAK SHORT WAVE TO PASS BY TO OUR SOUTH LATER THURSDAY WHICH
SHOULD HELP LOCK CLOUDS IN ACROSS THE REGION. WILL KEEP FORECAST DRY
BUT A FEW FLURRIES NOT OUT OF QUESTION. SEVERAL MORE WEAK SHORT
WAVES TO MOVE THROUGH BUT SHOULD STAY DRY THROUGH THE WEEKEND. A
STRONGER SYSTEM TO OUR SOUTH THIS WEEKEND STILL LOOKS TO STAY SOUTH
BUT WILL ALSO HELP TO KEEP SKIES CLOUDY.

THE END OF THIS PERIOD STILL LOOKS TO BE A CHALLENGE WITH A LOT OF
DIFFERENCES AMONG MODELS AND LACK OF CONFIDENCE IN ANY SPECIFIC
OUTCOME. MODELS ARE ALL IN AGREEMENT ON A DECENT STORM SYSTEM MOVING
THROUGH THE MIDWEST NEXT WEEK BUT SPECIFIC AND IMPORTANT DETAILS
VARY SIGNIFICANTLY IN THESE LONGER TIME PERIODS OF DAY 6 TO 9. FOR
NOW HAVE STAYED WITH THE CONSENSUS BLENDS OF MID CHANCE POP CATEGORY
TUESDAY. THERMAL PROFILES ALL OVER THE SPECTRUM BUT ACCUMULATING SNOWFALL
IS PLAUSIBLE BY CHRISTMAS EVE. THOSE WITH TRAVEL PLANS SHOULD STAY
TUNED AND STAY INFORMED AS DETAILS BECOME MORE CLEAR OVER THE NEXT
WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 549 AM EST WED DEC 17 2014

COLD AIR ADVECTION WILL CONTINUE TODAY. DRIER AIR WAS SPREADING
ACROSS NORTHERN INDIANA...SO EXPECT CLOUDY CONDITIONS WITH LAKE
EFFECT SNOW SHOWERS REMAINING MAINLY NORTHWEST AND NORTH OF SBN.
MVFR CIGS SHOULD IMPROVE BY LATE IN THE TAF PERIOD. WENT
OPTIMISTIC WITH VFR CONDITIONS AT BOTH SITES BY 00Z.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...SKIPPER
SHORT TERM...TUCEK
LONG TERM...LASHLEY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA







000
FXUS63 KIWX 171241
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
ISSUED BY NATIONAL WEATHER SERVICE INDIANAPOLIS IN
741 AM EST WED DEC 17 2014

.SYNOPSIS...
ISSUED AT 424 AM EST WED DEC 17 2014

COLDER CONDITIONS CAN BE EXPECTED TODAY. A FEW AREAS OF LIGHT
SNOW ALONG WITH PATCHY FREEZING DRIZZLE WILL CHANGE TO ALL SNOW
BEFORE ENDING EARLY TODAY. LIGHT LAKE EFFECT SNOW SHOWERS ACROSS
SOUTHERN LOWER MICHIGAN AND FAR NORTHERN INDIANA WILL LINGER
THROUGH TONIGHT WITH LIGHT SNOW ACCUMULATIONS POSSIBLE. HIGHS
TODAY WILL BE ONLY FROM 30 TO 35. LOWS TONIGHT WILL DIP INTO THE
UPPER TEENS TO MID 20S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 735 AM EST WED DEC 17 2014

NO SIGNIFICANT CHANGES MADE OTHER THAN REMOVAL OF PRE DAWN DATA AS
IT APPEARS LIGHT POST FRONTAL PRECIPITATION HAS ENDED. STILL
REMAINS A LOW THREAT FOR PRECIPITATION OFF THE LAKE BUT PRIMARILY
CONFINED TO LOCATIONS IN MICHIGAN OR NEARBY.

PREVIOUS DISCUSSION ISSUED AT 422 AM EST WED DEC 17 2014...

LIGHT POST FRONTAL PRECIPITATION HAD FORMED IN THE AREA OF COLD AIR
ADVECTION OVERNIGHT. NCEP MODELS WERE NOT HANDLING THIS LIGHT
PRECIPITATION VERY WELL. DEEPER LIFT HAD DIMINISHED...SO ONLY LIGHT
PRECIPITATION IS EXPECTED. HOWEVER... WHERE THE DENDRITIC GROWTH
ZONE WAS ABOVE THE CLOUD LAYER...PATCHY FREEZING DRIZZLE WAS BEING
REPORTED. COLD AIR ADVECTION EARLY THIS MORNING SHOULD HELP DEEPEN
THE COLD LAYER AND HELP TURN ANY REMAINING PRECIPITATION TO JUST
SNOW. FOR NOW...DUE TO THE PATCHY AND BRIEF NATURE OF THE FREEZING
DRIZZLE...HAVE ISSUED A SPECIAL WEATHER STATEMENT FOR NORTHERN
INDIANA AND NW OHIO. OTHERWISE...LIGHT LAKE EFFECT SNOW SHOWERS
SHOULD PERSIST. GIVEN DELTA T VALUES RISING TO AROUND 11C AND
RELATIVELY LOW INVERSION HEIGHTS...MINOR SNOW ACCUMULATIONS OVER THE
FAR SOUTHWEST CORNER OF LOWER MICHIGAN INTO ADJACENT AREAS OF
NORTHWEST INDIANA ARE POSSIBLE TODAY AND TONIGHT.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 422 AM EST WED DEC 17 2014

MOST OF THIS LONG TERM PERIOD WILL BE RELATIVELY QUIET WITH A
TRANSITION TO A MORE ACTIVE PATTERN BY END OF PERIOD AND INTO
CHRISTMAS.

LONG TERM PERIOD BEGINS ON THURSDAY WITH A LOW END LAKE ENHANCED
RESPONSE EXPECTED TO SEASONABLY COLD AIR AND SOME WEAK SYNOPTIC
FEATURES. SINGULARLY NOTHING REALLY STANDS OUT FOR LAKE EFFECT OR
SYNOPTIC PCPN BUT COLLECTIVELY THERE MAY BE A WINDOW FOR SOME LIGHT
SNOW SHOWERS OR DRIZZLE/FREEZING DRIZZLE. NAM12 SHOWS ELONGATED MID
LEVEL TROUGH AND AREA OF SHEARED VORTICITY SINKING SOUTHWARD THROUGH
THE LAKES REGION LATE TONIGHT. ASSOCIATED SURFACE TROUGH TO FOLLOW
BUT BECOMES STATIONARY OVER THE WESTERN LAKES AND INTERIOR MICHIGAN
THURSDAY AS DIABATIC HEATING FROM THE WARMER LAKES LEADS TO RESIDUAL
LAKE AGGREGATE TROUGHING. THIS TROUGH TO PROVIDE A CYCLONICALLY
CURVED FETCH DOWN THE LONG AXIS OF LAKE MICHIGAN. DELTA T VALUES WILL
ONLY BE MARGINAL IN THE 11 TO 13C RANGE AND MOISTURE WILL BE
CONFINED TO LOWEST 3KFT. THE DGZ IS NOT EVEN CLOSE TO SATURATED WITH
ONLY THE VERY TOP OF THE SATURATED LAYER NEARING THE -10C THRESHOLD.
WHAT MAKES THIS INTERESTING IS THE POSSIBILITY OF A FEW MESOVORTICES
DEVELOPING WITHIN AXIS OF SURFACE TROUGH NEAR THE LAKESHORE WHERE
DIFFERENTIAL HEATING AND CONVERGENCE WILL BE MAXIMIZED. THESE
PARAMETERS ARE SIMILAR TO THE LOCALLY STUDIED TYPE VI LAKE EFFECT
EVENTS BUT PARAMETERS ARE MUCH WEAKER THAN TYPICALLY EXPECTED.
HOWEVER...A SIMILAR CASE THIS FALL DID PRODUCE SEVERAL VORTICES
WHICH BRIEFLY ENHANCED PCPN NEAR THE LAKESHORE...THOUGH DELTA T
VALUES WERE SLIGHTLY HIGHER. NAM12 IS PICKING UP ON THIS POTENTIAL
WITH A RATHER STRONG 925MB VORTICITY SIGNATURE IN THE EXPECTED
LOCATION. THE LIMITING FACTORS ARE QUITE STRONG BUT BELIEVE THIS
SIGNATURE AND COMBINATION OF FEATURES WARRANT LOW TO MID CHANCE POPS
WITH SCATTERED WORDING. PCPN TYPE REMAINS A QUANDARY GIVEN THE LACK
OF ICE INTRODUCTION. WITH THE SMALL PROBABILITY OF THIS EVENT HAVE
OPTED TO STICK WITH SNOW SHOWERS FOR NOW AND EVALUATE HIGHER RES
GUIDANCE AS TIME NEARS AND SEE IF CONDITIONS COME TOGETHER. ANY SNOW
ACCUMULATIONS WILL BE LIGHT AND GENERALLY AN INCH OR LESS BUT ALSO
CONDITIONAL ON THIS ENHANCED DEVELOPMENT.

A WEAK SHORT WAVE TO PASS BY TO OUR SOUTH LATER THURSDAY WHICH
SHOULD HELP LOCK CLOUDS IN ACROSS THE REGION. WILL KEEP FORECAST DRY
BUT A FEW FLURRIES NOT OUT OF QUESTION. SEVERAL MORE WEAK SHORT
WAVES TO MOVE THROUGH BUT SHOULD STAY DRY THROUGH THE WEEKEND. A
STRONGER SYSTEM TO OUR SOUTH THIS WEEKEND STILL LOOKS TO STAY SOUTH
BUT WILL ALSO HELP TO KEEP SKIES CLOUDY.

THE END OF THIS PERIOD STILL LOOKS TO BE A CHALLENGE WITH A LOT OF
DIFFERENCES AMONG MODELS AND LACK OF CONFIDENCE IN ANY SPECIFIC
OUTCOME. MODELS ARE ALL IN AGREEMENT ON A DECENT STORM SYSTEM MOVING
THROUGH THE MIDWEST NEXT WEEK BUT SPECIFIC AND IMPORTANT DETAILS
VARY SIGNIFICANTLY IN THESE LONGER TIME PERIODS OF DAY 6 TO 9. FOR
NOW HAVE STAYED WITH THE CONSENSUS BLENDS OF MID CHANCE POP CATEGORY
TUESDAY. THERMAL PROFILES ALL OVER THE SPECTRUM BUT ACCUMULATING SNOWFALL
IS PLAUSIBLE BY CHRISTMAS EVE. THOSE WITH TRAVEL PLANS SHOULD STAY
TUNED AND STAY INFORMED AS DETAILS BECOME MORE CLEAR OVER THE NEXT
WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 549 AM EST WED DEC 17 2014

COLD AIR ADVECTION WILL CONTINUE TODAY. DRIER AIR WAS SPREADING
ACROSS NORTHERN INDIANA...SO EXPECT CLOUDY CONDITIONS WITH LAKE
EFFECT SNOW SHOWERS REMAINING MAINLY NORTHWEST AND NORTH OF SBN.
MVFR CIGS SHOULD IMPROVE BY LATE IN THE TAF PERIOD. WENT
OPTIMISTIC WITH VFR CONDITIONS AT BOTH SITES BY 00Z.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...SKIPPER
SHORT TERM...TUCEK
LONG TERM...LASHLEY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA








000
FXUS63 KIWX 171058
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
558 AM EST WED DEC 17 2014

.SYNOPSIS...
ISSUED AT 424 AM EST WED DEC 17 2014

COLDER CONDITIONS CAN BE EXPECTED TODAY. A FEW AREAS OF LIGHT
SNOW ALONG WITH PATCHY FREEZING DRIZZLE WILL CHANGE TO ALL SNOW
BEFORE ENDING EARLY TODAY. LIGHT LAKE EFFECT SNOW SHOWERS ACROSS
SOUTHERN LOWER MICHIGAN AND FAR NORTHERN INDIANA WILL LINGER
THROUGH TONIGHT WITH LIGHT SNOW ACCUMULATIONS POSSIBLE. HIGHS
TODAY WILL BE ONLY FROM 30 TO 35. LOWS TONIGHT WILL DIP INTO THE
UPPER TEENS TO MID 20S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 422 AM EST WED DEC 17 2014

LIGHT POST FRONTAL PRECIPITATION HAD FORMED IN THE AREA OF COLD AIR
ADVECTION OVERNIGHT. NCEP MODELS WERE NOT HANDLING THIS LIGHT
PRECIPITATION VERY WELL. DEEPER LIFT HAD DIMINISHED...SO ONLY LIGHT
PRECIPITATION IS EXPECTED. HOWEVER... WHERE THE DENDRITIC GROWTH
ZONE WAS ABOVE THE CLOUD LAYER...PATCHY FREEZING DRIZZLE WAS BEING
REPORTED. COLD AIR ADVECTION EARLY THIS MORNING SHOULD HELP DEEPEN
THE COLD LAYER AND HELP TURN ANY REMAINING PRECIPITATION TO JUST
SNOW. FOR NOW...DUE TO THE PATCHY AND BRIEF NATURE OF THE FREEZING
DRIZZLE...HAVE ISSUED A SPECIAL WEATHER STATEMENT FOR NORTHERN
INDIANA AND NW OHIO. OTHERWISE...LIGHT LAKE EFFECT SNOW SHOWERS
SHOULD PERSIST. GIVEN DELTA T VALUES RISING TO AROUND 11C AND
RELATIVELY LOW INVERSION HEIGHTS...MINOR SNOW ACCUMULATIONS OVER THE
FAR SOUTHWEST CORNER OF LOWER MICHIGAN INTO ADJACENT AREAS OF
NORTHWEST INDIANA ARE POSSIBLE TODAY AND TONIGHT.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 422 AM EST WED DEC 17 2014

MOST OF THIS LONG TERM PERIOD WILL BE RELATIVELY QUIET WITH A
TRANSITION TO A MORE ACTIVE PATTERN BY END OF PERIOD AND INTO
CHRISTMAS.

LONG TERM PERIOD BEGINS ON THURSDAY WITH A LOW END LAKE ENHANCED
RESPONSE EXPECTED TO SEASONABLY COLD AIR AND SOME WEAK SYNOPTIC
FEATURES. SINGULARLY NOTHING REALLY STANDS OUT FOR LAKE EFFECT OR
SYNOPTIC PCPN BUT COLLECTIVELY THERE MAY BE A WINDOW FOR SOME LIGHT
SNOW SHOWERS OR DRIZZLE/FREEZING DRIZZLE. NAM12 SHOWS ELONGATED MID
LEVEL TROUGH AND AREA OF SHEARED VORTICITY SINKING SOUTHWARD THROUGH
THE LAKES REGION LATE TONIGHT. ASSOCIATED SURFACE TROUGH TO FOLLOW
BUT BECOMES STATIONARY OVER THE WESTERN LAKES AND INTERIOR MICHIGAN
THURSDAY AS DIABATIC HEATING FROM THE WARMER LAKES LEADS TO RESIDUAL
LAKE AGGREGATE TROUGHING. THIS TROUGH TO PROVIDE A CYCLONICALLY
CURVED FETCH DOWN THE LONG AXIS OF LAKE MICHIGAN. DELTA T VALUES WILL
ONLY BE MARGINAL IN THE 11 TO 13C RANGE AND MOISTURE WILL BE
CONFINED TO LOWEST 3KFT. THE DGZ IS NOT EVEN CLOSE TO SATURATED WITH
ONLY THE VERY TOP OF THE SATURATED LAYER NEARING THE -10C THRESHOLD.
WHAT MAKES THIS INTERESTING IS THE POSSIBILITY OF A FEW MESOVORTICES
DEVELOPING WITHIN AXIS OF SURFACE TROUGH NEAR THE LAKESHORE WHERE
DIFFERENTIAL HEATING AND CONVERGENCE WILL BE MAXIMIZED. THESE
PARAMETERS ARE SIMILAR TO THE LOCALLY STUDIED TYPE VI LAKE EFFECT
EVENTS BUT PARAMETERS ARE MUCH WEAKER THAN TYPICALLY EXPECTED.
HOWEVER...A SIMILAR CASE THIS FALL DID PRODUCE SEVERAL VORTICES
WHICH BRIEFLY ENHANCED PCPN NEAR THE LAKESHORE...THOUGH DELTA T
VALUES WERE SLIGHTLY HIGHER. NAM12 IS PICKING UP ON THIS POTENTIAL
WITH A RATHER STRONG 925MB VORTICITY SIGNATURE IN THE EXPECTED
LOCATION. THE LIMITING FACTORS ARE QUITE STRONG BUT BELIEVE THIS
SIGNATURE AND COMBINATION OF FEATURES WARRANT LOW TO MID CHANCE POPS
WITH SCATTERED WORDING. PCPN TYPE REMAINS A QUANDARY GIVEN THE LACK
OF ICE INTRODUCTION. WITH THE SMALL PROBABILITY OF THIS EVENT HAVE
OPTED TO STICK WITH SNOW SHOWERS FOR NOW AND EVALUATE HIGHER RES
GUIDANCE AS TIME NEARS AND SEE IF CONDITIONS COME TOGETHER. ANY SNOW
ACCUMULATIONS WILL BE LIGHT AND GENERALLY AN INCH OR LESS BUT ALSO
CONDITIONAL ON THIS ENHANCED DEVELOPMENT.

A WEAK SHORT WAVE TO PASS BY TO OUR SOUTH LATER THURSDAY WHICH
SHOULD HELP LOCK CLOUDS IN ACROSS THE REGION. WILL KEEP FORECAST DRY
BUT A FEW FLURRIES NOT OUT OF QUESTION. SEVERAL MORE WEAK SHORT
WAVES TO MOVE THROUGH BUT SHOULD STAY DRY THROUGH THE WEEKEND. A
STRONGER SYSTEM TO OUR SOUTH THIS WEEKEND STILL LOOKS TO STAY SOUTH
BUT WILL ALSO HELP TO KEEP SKIES CLOUDY.

THE END OF THIS PERIOD STILL LOOKS TO BE A CHALLENGE WITH A LOT OF
DIFFERENCES AMONG MODELS AND LACK OF CONFIDENCE IN ANY SPECIFIC
OUTCOME. MODELS ARE ALL IN AGREEMENT ON A DECENT STORM SYSTEM MOVING
THROUGH THE MIDWEST NEXT WEEK BUT SPECIFIC AND IMPORTANT DETAILS
VARY SIGNIFICANTLY IN THESE LONGER TIME PERIODS OF DAY 6 TO 9. FOR
NOW HAVE STAYED WITH THE CONSENSUS BLENDS OF MID CHANCE POP CATEGORY
TUESDAY. THERMAL PROFILES ALL OVER THE SPECTRUM BUT ACCUMULATING SNOWFALL
IS PLAUSIBLE BY CHRISTMAS EVE. THOSE WITH TRAVEL PLANS SHOULD STAY
TUNED AND STAY INFORMED AS DETAILS BECOME MORE CLEAR OVER THE NEXT
WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 549 AM EST WED DEC 17 2014

COLD AIR ADVECTION WILL CONTINUE TODAY. DRIER AIR WAS SPREADING
ACROSS NORTHERN INDIANA...SO EXPECT CLOUDY CONDITIONS WITH LAKE
EFFECT SNOW SHOWERS REMAINING MAINLY NORTHWEST AND NORTH OF SBN.
MVFR CIGS SHOULD IMPROVE BY LATE IN THE TAF PERIOD. WENT
OPTIMISTIC WITH VFR CONDITIONS AT BOTH SITES BY 00Z.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...SKIPPER
SHORT TERM...SKIPPER
LONG TERM...LASHLEY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA








000
FXUS63 KIWX 171058
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
558 AM EST WED DEC 17 2014

.SYNOPSIS...
ISSUED AT 424 AM EST WED DEC 17 2014

COLDER CONDITIONS CAN BE EXPECTED TODAY. A FEW AREAS OF LIGHT
SNOW ALONG WITH PATCHY FREEZING DRIZZLE WILL CHANGE TO ALL SNOW
BEFORE ENDING EARLY TODAY. LIGHT LAKE EFFECT SNOW SHOWERS ACROSS
SOUTHERN LOWER MICHIGAN AND FAR NORTHERN INDIANA WILL LINGER
THROUGH TONIGHT WITH LIGHT SNOW ACCUMULATIONS POSSIBLE. HIGHS
TODAY WILL BE ONLY FROM 30 TO 35. LOWS TONIGHT WILL DIP INTO THE
UPPER TEENS TO MID 20S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 422 AM EST WED DEC 17 2014

LIGHT POST FRONTAL PRECIPITATION HAD FORMED IN THE AREA OF COLD AIR
ADVECTION OVERNIGHT. NCEP MODELS WERE NOT HANDLING THIS LIGHT
PRECIPITATION VERY WELL. DEEPER LIFT HAD DIMINISHED...SO ONLY LIGHT
PRECIPITATION IS EXPECTED. HOWEVER... WHERE THE DENDRITIC GROWTH
ZONE WAS ABOVE THE CLOUD LAYER...PATCHY FREEZING DRIZZLE WAS BEING
REPORTED. COLD AIR ADVECTION EARLY THIS MORNING SHOULD HELP DEEPEN
THE COLD LAYER AND HELP TURN ANY REMAINING PRECIPITATION TO JUST
SNOW. FOR NOW...DUE TO THE PATCHY AND BRIEF NATURE OF THE FREEZING
DRIZZLE...HAVE ISSUED A SPECIAL WEATHER STATEMENT FOR NORTHERN
INDIANA AND NW OHIO. OTHERWISE...LIGHT LAKE EFFECT SNOW SHOWERS
SHOULD PERSIST. GIVEN DELTA T VALUES RISING TO AROUND 11C AND
RELATIVELY LOW INVERSION HEIGHTS...MINOR SNOW ACCUMULATIONS OVER THE
FAR SOUTHWEST CORNER OF LOWER MICHIGAN INTO ADJACENT AREAS OF
NORTHWEST INDIANA ARE POSSIBLE TODAY AND TONIGHT.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 422 AM EST WED DEC 17 2014

MOST OF THIS LONG TERM PERIOD WILL BE RELATIVELY QUIET WITH A
TRANSITION TO A MORE ACTIVE PATTERN BY END OF PERIOD AND INTO
CHRISTMAS.

LONG TERM PERIOD BEGINS ON THURSDAY WITH A LOW END LAKE ENHANCED
RESPONSE EXPECTED TO SEASONABLY COLD AIR AND SOME WEAK SYNOPTIC
FEATURES. SINGULARLY NOTHING REALLY STANDS OUT FOR LAKE EFFECT OR
SYNOPTIC PCPN BUT COLLECTIVELY THERE MAY BE A WINDOW FOR SOME LIGHT
SNOW SHOWERS OR DRIZZLE/FREEZING DRIZZLE. NAM12 SHOWS ELONGATED MID
LEVEL TROUGH AND AREA OF SHEARED VORTICITY SINKING SOUTHWARD THROUGH
THE LAKES REGION LATE TONIGHT. ASSOCIATED SURFACE TROUGH TO FOLLOW
BUT BECOMES STATIONARY OVER THE WESTERN LAKES AND INTERIOR MICHIGAN
THURSDAY AS DIABATIC HEATING FROM THE WARMER LAKES LEADS TO RESIDUAL
LAKE AGGREGATE TROUGHING. THIS TROUGH TO PROVIDE A CYCLONICALLY
CURVED FETCH DOWN THE LONG AXIS OF LAKE MICHIGAN. DELTA T VALUES WILL
ONLY BE MARGINAL IN THE 11 TO 13C RANGE AND MOISTURE WILL BE
CONFINED TO LOWEST 3KFT. THE DGZ IS NOT EVEN CLOSE TO SATURATED WITH
ONLY THE VERY TOP OF THE SATURATED LAYER NEARING THE -10C THRESHOLD.
WHAT MAKES THIS INTERESTING IS THE POSSIBILITY OF A FEW MESOVORTICES
DEVELOPING WITHIN AXIS OF SURFACE TROUGH NEAR THE LAKESHORE WHERE
DIFFERENTIAL HEATING AND CONVERGENCE WILL BE MAXIMIZED. THESE
PARAMETERS ARE SIMILAR TO THE LOCALLY STUDIED TYPE VI LAKE EFFECT
EVENTS BUT PARAMETERS ARE MUCH WEAKER THAN TYPICALLY EXPECTED.
HOWEVER...A SIMILAR CASE THIS FALL DID PRODUCE SEVERAL VORTICES
WHICH BRIEFLY ENHANCED PCPN NEAR THE LAKESHORE...THOUGH DELTA T
VALUES WERE SLIGHTLY HIGHER. NAM12 IS PICKING UP ON THIS POTENTIAL
WITH A RATHER STRONG 925MB VORTICITY SIGNATURE IN THE EXPECTED
LOCATION. THE LIMITING FACTORS ARE QUITE STRONG BUT BELIEVE THIS
SIGNATURE AND COMBINATION OF FEATURES WARRANT LOW TO MID CHANCE POPS
WITH SCATTERED WORDING. PCPN TYPE REMAINS A QUANDARY GIVEN THE LACK
OF ICE INTRODUCTION. WITH THE SMALL PROBABILITY OF THIS EVENT HAVE
OPTED TO STICK WITH SNOW SHOWERS FOR NOW AND EVALUATE HIGHER RES
GUIDANCE AS TIME NEARS AND SEE IF CONDITIONS COME TOGETHER. ANY SNOW
ACCUMULATIONS WILL BE LIGHT AND GENERALLY AN INCH OR LESS BUT ALSO
CONDITIONAL ON THIS ENHANCED DEVELOPMENT.

A WEAK SHORT WAVE TO PASS BY TO OUR SOUTH LATER THURSDAY WHICH
SHOULD HELP LOCK CLOUDS IN ACROSS THE REGION. WILL KEEP FORECAST DRY
BUT A FEW FLURRIES NOT OUT OF QUESTION. SEVERAL MORE WEAK SHORT
WAVES TO MOVE THROUGH BUT SHOULD STAY DRY THROUGH THE WEEKEND. A
STRONGER SYSTEM TO OUR SOUTH THIS WEEKEND STILL LOOKS TO STAY SOUTH
BUT WILL ALSO HELP TO KEEP SKIES CLOUDY.

THE END OF THIS PERIOD STILL LOOKS TO BE A CHALLENGE WITH A LOT OF
DIFFERENCES AMONG MODELS AND LACK OF CONFIDENCE IN ANY SPECIFIC
OUTCOME. MODELS ARE ALL IN AGREEMENT ON A DECENT STORM SYSTEM MOVING
THROUGH THE MIDWEST NEXT WEEK BUT SPECIFIC AND IMPORTANT DETAILS
VARY SIGNIFICANTLY IN THESE LONGER TIME PERIODS OF DAY 6 TO 9. FOR
NOW HAVE STAYED WITH THE CONSENSUS BLENDS OF MID CHANCE POP CATEGORY
TUESDAY. THERMAL PROFILES ALL OVER THE SPECTRUM BUT ACCUMULATING SNOWFALL
IS PLAUSIBLE BY CHRISTMAS EVE. THOSE WITH TRAVEL PLANS SHOULD STAY
TUNED AND STAY INFORMED AS DETAILS BECOME MORE CLEAR OVER THE NEXT
WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 549 AM EST WED DEC 17 2014

COLD AIR ADVECTION WILL CONTINUE TODAY. DRIER AIR WAS SPREADING
ACROSS NORTHERN INDIANA...SO EXPECT CLOUDY CONDITIONS WITH LAKE
EFFECT SNOW SHOWERS REMAINING MAINLY NORTHWEST AND NORTH OF SBN.
MVFR CIGS SHOULD IMPROVE BY LATE IN THE TAF PERIOD. WENT
OPTIMISTIC WITH VFR CONDITIONS AT BOTH SITES BY 00Z.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...SKIPPER
SHORT TERM...SKIPPER
LONG TERM...LASHLEY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA







000
FXUS63 KIWX 170928
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
428 AM EST WED DEC 17 2014

.SYNOPSIS...
ISSUED AT 424 AM EST WED DEC 17 2014

COLDER CONDITIONS CAN BE EXPECTED TODAY. A FEW AREAS OF LIGHT
SNOW ALONG WITH PATCHY FREEZING DRIZZLE WILL CHANGE TO ALL SNOW
BEFORE ENDING EARLY TODAY. LIGHT LAKE EFFECT SNOW SHOWERS ACROSS
SOUTHERN LOWER MICHIGAN AND FAR NORTHERN INDIANA WILL LINGER
THROUGH TONIGHT WITH LIGHT SNOW ACCUMULATIONS POSSIBLE. HIGHS
TODAY WILL BE ONLY FROM 30 TO 35. LOWS TONIGHT WILL DIP INTO THE
UPPER TEENS TO MID 20S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 422 AM EST WED DEC 17 2014

LIGHT POST FRONTAL PRECIPITATION HAD FORMED IN THE AREA OF COLD AIR
ADVECTION OVERNIGHT. NCEP MODELS WERE NOT HANDLING THIS LIGHT
PRECIPITATION VERY WELL. DEEPER LIFT HAD DIMINISHED...SO ONLY LIGHT
PRECIPITATION IS EXPECTED. HOWEVER... WHERE THE DENDRITIC GROWTH
ZONE WAS ABOVE THE CLOUD LAYER...PATCHY FREEZING DRIZZLE WAS BEING
REPORTED. COLD AIR ADVECTION EARLY THIS MORNING SHOULD HELP DEEPEN
THE COLD LAYER AND HELP TURN ANY REMAINING PRECIPITATION TO JUST
SNOW. FOR NOW...DUE TO THE PATCHY AND BRIEF NATURE OF THE FREEZING
DRIZZLE...HAVE ISSUED A SPECIAL WEATHER STATEMENT FOR NORTHERN
INDIANA AND NW OHIO. OTHERWISE...LIGHT LAKE EFFECT SNOW SHOWERS
SHOULD PERSIST. GIVEN DELTA T VALUES RISING TO AROUND 11C AND
RELATIVELY LOW INVERSION HEIGHTS...MINOR SNOW ACCUMULATIONS OVER THE
FAR SOUTHWEST CORNER OF LOWER MICHIGAN INTO ADJACENT AREAS OF
NORTHWEST INDIANA ARE POSSIBLE TODAY AND TONIGHT.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 422 AM EST WED DEC 17 2014

MOST OF THIS LONG TERM PERIOD WILL BE RELATIVELY QUIET WITH A
TRANSITION TO A MORE ACTIVE PATTERN BY END OF PERIOD AND INTO
CHRISTMAS.

LONG TERM PERIOD BEGINS ON THURSDAY WITH A LOW END LAKE ENHANCED
RESPONSE EXPECTED TO SEASONABLY COLD AIR AND SOME WEAK SYNOPTIC
FEATURES. SINGULARLY NOTHING REALLY STANDS OUT FOR LAKE EFFECT OR
SYNOPTIC PCPN BUT COLLECTIVELY THERE MAY BE A WINDOW FOR SOME LIGHT
SNOW SHOWERS OR DRIZZLE/FREEZING DRIZZLE. NAM12 SHOWS ELONGATED MID
LEVEL TROUGH AND AREA OF SHEARED VORTICITY SINKING SOUTHWARD THROUGH
THE LAKES REGION LATE TONIGHT. ASSOCIATED SURFACE TROUGH TO FOLLOW
BUT BECOMES STATIONARY OVER THE WESTERN LAKES AND INTERIOR MICHIGAN
THURSDAY AS DIABATIC HEATING FROM THE WARMER LAKES LEADS TO RESIDUAL
LAKE AGGREGATE TROUGHING. THIS TROUGH TO PROVIDE A CYCLONICALLY
CURVED FETCH DOWN THE LONG AXIS OF LAKE MICHIGAN. DELTA T VALUES WILL
ONLY BE MARGINAL IN THE 11 TO 13C RANGE AND MOISTURE WILL BE
CONFINED TO LOWEST 3KFT. THE DGZ IS NOT EVEN CLOSE TO SATURATED WITH
ONLY THE VERY TOP OF THE SATURATED LAYER NEARING THE -10C THRESHOLD.
WHAT MAKES THIS INTERESTING IS THE POSSIBILITY OF A FEW MESOVORTICES
DEVELOPING WITHIN AXIS OF SURFACE TROUGH NEAR THE LAKESHORE WHERE
DIFFERENTIAL HEATING AND CONVERGENCE WILL BE MAXIMIZED. THESE
PARAMETERS ARE SIMILAR TO THE LOCALLY STUDIED TYPE VI LAKE EFFECT
EVENTS BUT PARAMETERS ARE MUCH WEAKER THAN TYPICALLY EXPECTED.
HOWEVER...A SIMILAR CASE THIS FALL DID PRODUCE SEVERAL VORTICES
WHICH BRIEFLY ENHANCED PCPN NEAR THE LAKESHORE...THOUGH DELTA T
VALUES WERE SLIGHTLY HIGHER. NAM12 IS PICKING UP ON THIS POTENTIAL
WITH A RATHER STRONG 925MB VORTICITY SIGNATURE IN THE EXPECTED
LOCATION. THE LIMITING FACTORS ARE QUITE STRONG BUT BELIEVE THIS
SIGNATURE AND COMBINATION OF FEATURES WARRANT LOW TO MID CHANCE POPS
WITH SCATTERED WORDING. PCPN TYPE REMAINS A QUANDARY GIVEN THE LACK
OF ICE INTRODUCTION. WITH THE SMALL PROBABILITY OF THIS EVENT HAVE
OPTED TO STICK WITH SNOW SHOWERS FOR NOW AND EVALUATE HIGHER RES
GUIDANCE AS TIME NEARS AND SEE IF CONDITIONS COME TOGETHER. ANY SNOW
ACCUMULATIONS WILL BE LIGHT AND GENERALLY AN INCH OR LESS BUT ALSO
CONDITIONAL ON THIS ENHANCED DEVELOPMENT.

A WEAK SHORT WAVE TO PASS BY TO OUR SOUTH LATER THURSDAY WHICH
SHOULD HELP LOCK CLOUDS IN ACROSS THE REGION. WILL KEEP FORECAST DRY
BUT A FEW FLURRIES NOT OUT OF QUESTION. SEVERAL MORE WEAK SHORT
WAVES TO MOVE THROUGH BUT SHOULD STAY DRY THROUGH THE WEEKEND. A
STRONGER SYSTEM TO OUR SOUTH THIS WEEKEND STILL LOOKS TO STAY SOUTH
BUT WILL ALSO HELP TO KEEP SKIES CLOUDY.

THE END OF THIS PERIOD STILL LOOKS TO BE A CHALLENGE WITH A LOT OF
DIFFERENCES AMONG MODELS AND LACK OF CONFIDENCE IN ANY SPECIFIC
OUTCOME. MODELS ARE ALL IN AGREEMENT ON A DECENT STORM SYSTEM MOVING
THROUGH THE MIDWEST NEXT WEEK BUT SPECIFIC AND IMPORTANT DETAILS
VARY SIGNIFICANTLY IN THESE LONGER TIME PERIODS OF DAY 6 TO 9. FOR
NOW HAVE STAYED WITH THE CONSENSUS BLENDS OF MID CHANCE POP CATEGORY
TUESDAY. THERMAL PROFILES ALL OVER THE SPECTRUM BUT ACCUMULATING SNOWFALL
IS PLAUSIBLE BY CHRISTMAS EVE. THOSE WITH TRAVEL PLANS SHOULD STAY
TUNED AND STAY INFORMED AS DETAILS BECOME MORE CLEAR OVER THE NEXT
WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 102 AM EST WED DEC 17 2014

ONE LAST AREA OF LIGHT PRECIPITATION WILL CONTINUE TO MOVE ACROSS
NORTHERN INDIANA EARLY IN THE TAF PERIOD. A RAIN/SNOW MIX WILL
RAPIDLY CHANGE TO ALL SNOW BEFORE ENDING. A BRIEF IFR CIG AT FT
WAYNE IS POSSIBLE BEFORE THE PRECIPITATION ENDS. OTHERWISE...MVFR
CIGS SHOULD PERSIST THROUGH THE TAF PERIOD AS THE UPPER LOW
LINGERS OVER THE REGION WITH PLENTY OF MVFR CLOUDS UPSTREAM.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...SKIPPER
SHORT TERM...SKIPPER
LONG TERM...LASHLEY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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000
FXUS63 KIWX 170928
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
428 AM EST WED DEC 17 2014

.SYNOPSIS...
ISSUED AT 424 AM EST WED DEC 17 2014

COLDER CONDITIONS CAN BE EXPECTED TODAY. A FEW AREAS OF LIGHT
SNOW ALONG WITH PATCHY FREEZING DRIZZLE WILL CHANGE TO ALL SNOW
BEFORE ENDING EARLY TODAY. LIGHT LAKE EFFECT SNOW SHOWERS ACROSS
SOUTHERN LOWER MICHIGAN AND FAR NORTHERN INDIANA WILL LINGER
THROUGH TONIGHT WITH LIGHT SNOW ACCUMULATIONS POSSIBLE. HIGHS
TODAY WILL BE ONLY FROM 30 TO 35. LOWS TONIGHT WILL DIP INTO THE
UPPER TEENS TO MID 20S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 422 AM EST WED DEC 17 2014

LIGHT POST FRONTAL PRECIPITATION HAD FORMED IN THE AREA OF COLD AIR
ADVECTION OVERNIGHT. NCEP MODELS WERE NOT HANDLING THIS LIGHT
PRECIPITATION VERY WELL. DEEPER LIFT HAD DIMINISHED...SO ONLY LIGHT
PRECIPITATION IS EXPECTED. HOWEVER... WHERE THE DENDRITIC GROWTH
ZONE WAS ABOVE THE CLOUD LAYER...PATCHY FREEZING DRIZZLE WAS BEING
REPORTED. COLD AIR ADVECTION EARLY THIS MORNING SHOULD HELP DEEPEN
THE COLD LAYER AND HELP TURN ANY REMAINING PRECIPITATION TO JUST
SNOW. FOR NOW...DUE TO THE PATCHY AND BRIEF NATURE OF THE FREEZING
DRIZZLE...HAVE ISSUED A SPECIAL WEATHER STATEMENT FOR NORTHERN
INDIANA AND NW OHIO. OTHERWISE...LIGHT LAKE EFFECT SNOW SHOWERS
SHOULD PERSIST. GIVEN DELTA T VALUES RISING TO AROUND 11C AND
RELATIVELY LOW INVERSION HEIGHTS...MINOR SNOW ACCUMULATIONS OVER THE
FAR SOUTHWEST CORNER OF LOWER MICHIGAN INTO ADJACENT AREAS OF
NORTHWEST INDIANA ARE POSSIBLE TODAY AND TONIGHT.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 422 AM EST WED DEC 17 2014

MOST OF THIS LONG TERM PERIOD WILL BE RELATIVELY QUIET WITH A
TRANSITION TO A MORE ACTIVE PATTERN BY END OF PERIOD AND INTO
CHRISTMAS.

LONG TERM PERIOD BEGINS ON THURSDAY WITH A LOW END LAKE ENHANCED
RESPONSE EXPECTED TO SEASONABLY COLD AIR AND SOME WEAK SYNOPTIC
FEATURES. SINGULARLY NOTHING REALLY STANDS OUT FOR LAKE EFFECT OR
SYNOPTIC PCPN BUT COLLECTIVELY THERE MAY BE A WINDOW FOR SOME LIGHT
SNOW SHOWERS OR DRIZZLE/FREEZING DRIZZLE. NAM12 SHOWS ELONGATED MID
LEVEL TROUGH AND AREA OF SHEARED VORTICITY SINKING SOUTHWARD THROUGH
THE LAKES REGION LATE TONIGHT. ASSOCIATED SURFACE TROUGH TO FOLLOW
BUT BECOMES STATIONARY OVER THE WESTERN LAKES AND INTERIOR MICHIGAN
THURSDAY AS DIABATIC HEATING FROM THE WARMER LAKES LEADS TO RESIDUAL
LAKE AGGREGATE TROUGHING. THIS TROUGH TO PROVIDE A CYCLONICALLY
CURVED FETCH DOWN THE LONG AXIS OF LAKE MICHIGAN. DELTA T VALUES WILL
ONLY BE MARGINAL IN THE 11 TO 13C RANGE AND MOISTURE WILL BE
CONFINED TO LOWEST 3KFT. THE DGZ IS NOT EVEN CLOSE TO SATURATED WITH
ONLY THE VERY TOP OF THE SATURATED LAYER NEARING THE -10C THRESHOLD.
WHAT MAKES THIS INTERESTING IS THE POSSIBILITY OF A FEW MESOVORTICES
DEVELOPING WITHIN AXIS OF SURFACE TROUGH NEAR THE LAKESHORE WHERE
DIFFERENTIAL HEATING AND CONVERGENCE WILL BE MAXIMIZED. THESE
PARAMETERS ARE SIMILAR TO THE LOCALLY STUDIED TYPE VI LAKE EFFECT
EVENTS BUT PARAMETERS ARE MUCH WEAKER THAN TYPICALLY EXPECTED.
HOWEVER...A SIMILAR CASE THIS FALL DID PRODUCE SEVERAL VORTICES
WHICH BRIEFLY ENHANCED PCPN NEAR THE LAKESHORE...THOUGH DELTA T
VALUES WERE SLIGHTLY HIGHER. NAM12 IS PICKING UP ON THIS POTENTIAL
WITH A RATHER STRONG 925MB VORTICITY SIGNATURE IN THE EXPECTED
LOCATION. THE LIMITING FACTORS ARE QUITE STRONG BUT BELIEVE THIS
SIGNATURE AND COMBINATION OF FEATURES WARRANT LOW TO MID CHANCE POPS
WITH SCATTERED WORDING. PCPN TYPE REMAINS A QUANDARY GIVEN THE LACK
OF ICE INTRODUCTION. WITH THE SMALL PROBABILITY OF THIS EVENT HAVE
OPTED TO STICK WITH SNOW SHOWERS FOR NOW AND EVALUATE HIGHER RES
GUIDANCE AS TIME NEARS AND SEE IF CONDITIONS COME TOGETHER. ANY SNOW
ACCUMULATIONS WILL BE LIGHT AND GENERALLY AN INCH OR LESS BUT ALSO
CONDITIONAL ON THIS ENHANCED DEVELOPMENT.

A WEAK SHORT WAVE TO PASS BY TO OUR SOUTH LATER THURSDAY WHICH
SHOULD HELP LOCK CLOUDS IN ACROSS THE REGION. WILL KEEP FORECAST DRY
BUT A FEW FLURRIES NOT OUT OF QUESTION. SEVERAL MORE WEAK SHORT
WAVES TO MOVE THROUGH BUT SHOULD STAY DRY THROUGH THE WEEKEND. A
STRONGER SYSTEM TO OUR SOUTH THIS WEEKEND STILL LOOKS TO STAY SOUTH
BUT WILL ALSO HELP TO KEEP SKIES CLOUDY.

THE END OF THIS PERIOD STILL LOOKS TO BE A CHALLENGE WITH A LOT OF
DIFFERENCES AMONG MODELS AND LACK OF CONFIDENCE IN ANY SPECIFIC
OUTCOME. MODELS ARE ALL IN AGREEMENT ON A DECENT STORM SYSTEM MOVING
THROUGH THE MIDWEST NEXT WEEK BUT SPECIFIC AND IMPORTANT DETAILS
VARY SIGNIFICANTLY IN THESE LONGER TIME PERIODS OF DAY 6 TO 9. FOR
NOW HAVE STAYED WITH THE CONSENSUS BLENDS OF MID CHANCE POP CATEGORY
TUESDAY. THERMAL PROFILES ALL OVER THE SPECTRUM BUT ACCUMULATING SNOWFALL
IS PLAUSIBLE BY CHRISTMAS EVE. THOSE WITH TRAVEL PLANS SHOULD STAY
TUNED AND STAY INFORMED AS DETAILS BECOME MORE CLEAR OVER THE NEXT
WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 102 AM EST WED DEC 17 2014

ONE LAST AREA OF LIGHT PRECIPITATION WILL CONTINUE TO MOVE ACROSS
NORTHERN INDIANA EARLY IN THE TAF PERIOD. A RAIN/SNOW MIX WILL
RAPIDLY CHANGE TO ALL SNOW BEFORE ENDING. A BRIEF IFR CIG AT FT
WAYNE IS POSSIBLE BEFORE THE PRECIPITATION ENDS. OTHERWISE...MVFR
CIGS SHOULD PERSIST THROUGH THE TAF PERIOD AS THE UPPER LOW
LINGERS OVER THE REGION WITH PLENTY OF MVFR CLOUDS UPSTREAM.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...SKIPPER
SHORT TERM...SKIPPER
LONG TERM...LASHLEY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA







000
FXUS63 KIWX 170629
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
129 AM EST WED DEC 17 2014

.SYNOPSIS...
ISSUED AT 103 AM EST WED DEC 17 2014

A COUPLE OF UPPER LEVEL SHORT WAVES WILL MOVE OUT OF THE REGION
TONIGHT. A FEW AREAS OF LIGHT RAIN AND LIGHT SNOW WILL CHANGE TO
ALL SNOW BEFORE ENDING EXCEPT FOR SOME LINGERS LIGHT LAKE EFFECT
SNOW SHOWERS ACROSS SOUTHERN LOWER MICHIGAN AND FAR NORTHERN
INDIANA. SOME LIGHT SNOW ACCUMULATION IS POSSIBLE...MAINLY ON
GRASSY AREAS. LOW TEMPERATURES TONIGHT WILL RANGE FROM THE MID 20S
ACROSS NORTHEAST ILLINOIS...TO THE LOWER 30S ACROSS NORTHWEST
OHIO. HIGH TEMPERATURES TODAY WILL BE ONLY FROM 30 TO 35.

&&

.UPDATE...
ISSUED AT 931 PM EST TUE DEC 16 2014

PRECIP COVERAGE IS EXPECTED TO DIMINISH OVER THE NEXT FEW HOURS AS
UPPER VORT LOBE ACROSS SOUTHERN LAKE MICHIGAN CONTINUES TO GET
SHEARED IN STRONG BACKGROUND DEFORMATION FLOW. THIS SHOULD LEAD TO
INCREASING SYNOPTIC SCALE SUBSIDENCE OVERNIGHT...WITH REMAINING
PRECIP AFTER 06Z CONFINED TO LIGHT LAKE EFFECT. LAKE EFFECT SETUP STILL
APPEARS TO BE QUITE UNFAVORABLE GIVEN DRY MID LEVEL
PROFILES/SUBSIDENCE...MARGINAL SATURATION AT DEPTHS SUPPORTIVE OF
ICE INTRODUCTION FOR -SHSN...AND LIMITING WESTERLY FETCH. STILL
SOME CHANCE FOR SOME PATCHY LIGHT FREEZING DRIZZLE IN ASSOCIATION
WITH THIS LAKE EFFECT PRECIP...BUT HAVE OPTED TO CONTINUE TO OMIT
THIS MENTION WITH LOW CONFIDENCE OF OCCURRENCE.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 324 PM EST TUE DEC 16 2014

AFTERNOON WATER VAPOR SHOWS SMALLER SCALE VORT MAXES (ONE NEAR THE
IN/OH BORDER AND ANOTHER OVER CENTRAL LAKE MI) EMBEDDED IN PARENT
GREAT LAKES MID-UPPER LEVEL CIRCULATION/OCCLUSION...WITH A
SEPARATE NORTHERN STREAM SHORTWAVE DROPPING SE INTO THE UPPER
MIDWEST. AT THE SFC (19Z)...THERE IS A 1005 MB SFC LOW CENTERED
OVER SE LOWER MI... WITH A COLD FRONT EXTENDING SW INTO SW LOWER
MI AND WESTERN INDIANA. SCT SHOWERS/DRIZZLE ACCOMPANYING THE
CDFNT/MOIST CYCLONIC FLOW AND MORE ORGANIZED AREA OF LIGHT RAIN
TIED TO IMPULSE NOW WORKING INTO WESTERN OH WILL CONTINUE TO PUSH
EAST RESULTING IN A DOWNTREND IN SHOWER/DRIZZLE COVERAGE THIS
EVENING. ANY LINGERING PCPN COULD END AS A FEW SNOW SHOWERS/SNIZZLE
ACROSS THE NORTH LATE THIS EVENING AS COLDER AIR BEGINS TO
UNDERCUT.

THE AFOREMENTIONED NORTHERN STREAM TROUGH WILL ELONGATE INTO THE
CENTRAL LAKES AND BECOME ORIENTED MORE WEST TO EAST OVERNIGHT INTO
WEDNESDAY. THIS FEATURE WILL HELP KICK THE LOWER LAKES SYSTEM OUT
OF THE AREA WITH DRIER/SUBSIDENT AIR ADVECTING IN ON THE SOUTHERN
FLANK OF A STRUNG OUT CENTRAL LAKES MID LEVEL DEFORMATION AXIS.
THE RESULT WILL BE A TREND TOWARD DRY/COLDER/SOMEWHAT BREEZY
CONDITIONS IN WEAK CAA REGIME. VEERED WNW FLOW WITHIN BOUNDARY
LAYER WITH LAKE-8H DIFFERENTIALS REACHING THE LOW TEENS WILL KEEP
LOW CLOUDS AROUND INTO TOMORROW. MARGINAL DELTA T`S/INVERSION
HEIGHTS AND SHALLOW MOISTURE PROFILES SUPPORT INHERITED LOW-MID
CHC POPS FOR SCT LAKE EFFECT SNOW SHOWERS/FLURRIES AND LITTLE/NO
ACCUMS. QUICK PERUSAL OF FCST SOUNDINGS/XSECTIONS SHOWING BULK OF
MOISTURE BELOW THE -12C LAYER ALSO CONCERNING FOR ANY ICE
PRODUCTION AND DZ/FZDZ POTENTIAL. WILL HOLD OFF ON ADDING DZ/FZDZ
IN THE FCST GIVEN LOW PROBABILITY OF OCCURRENCE. DRY AND FEELING
MUCH MORE LIKE MID DECEMBER OTHERWISE TOMORROW.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 324 PM EST TUE DEC 16 2014

INCREASINGLY ACTIVE PATTERN UNFOLDING FOR THE LONG TERM AND BEYOND.
FOCUS WILL BE ON 2 SYSTEMS FOR THE CURRENT PERIOD...ONE FOR THIS
WEEKEND AND THE OTHER ARRIVING PRIOR TO CHRISTMAS.

NW FLOW OFF LAKE MICHIGAN WILL PROVIDE INCREASED CLOUD COVER BUT
QUESTIONABLE IMPACTS IN TERMS OF PRECIPITATION AS COMBINATION OF
MARGINAL DELTA T`S...POTENTIAL FOR DRY AIR ENTRAINMENT AND LOW
INVERSION HEIGHTS ALL LEAD TO LESS THAN IDEAL CONDITIONS FOR
ACCUMULATING SNOWFALL. WILL LIKELY BE AT LEAST SCATTERED SNOW
SHOWERS AROUND...SO WILL MATCH UP WITH COVERAGE WORDING BUT HAVE
LITTLE/NO ACCUMULATIONS. LONGWAVE TROUGH MOVING ACROSS THE
WESTERN STATES WILL DIG INTO TEXAS AND PICK UP A PIECE OF ENERGY
COMING OUT OF THE 4 CORNERS AREA. ALL SIGNS CONTINUE TO POINT
TOWARDS A SUPPRESSED SOLUTION WITH THE LOW TRACKING FROM THE GULF OF
MEXICO NE TO ALONG THE APPALACHIANS SAT/SAT NGT. WHILE PLENTY OF
MSTR WILL EXIST WITH THE SYSTEM...FURTHER EAST TRACK WILL KEEP THE
AREA FROM SEEING ANY MAJOR IMPACTS WITH MAYBE SOME LIGHT
SNOW/FLURRIES.

HIGH PRESSURE WILL BUILD IN FOR SUNDAY INTO MONDAY TO BRING
SEASONABLE TEMPERATURES AND DRY CONDITIONS. FROM THIS POINT
FORWARD...MUCH MORE VOLATILE PATTERN SETS UP WITH NEXT PIECE OF
ENERGY (CLIPPER TYPE) DIVING OUT OF THE PLAINS INTO THE NORTHERN
GREAT LAKES. A COLD FRONT WILL EXTEND FROM THE LOW AND BRING A
CHANCE FOR SNOW SHOWERS TO THE AREA AT THE END OF THE PERIOD. EXACT
COVERAGE AND IMPACTS ARE STILL UNCERTAIN WITH GFS DEEPENING THE SFC
LOW OVER NE WISCONSIN BY TUESDAY AFTERNOON VS MAIN LOW STILL UP BY
THE ARROWHEAD OF MINNESOTA ON THE ECMWF. CONFIDENCE LOW IN EVOLUTION
OF THIS SYSTEM AND ALSO ADDITIONAL ENERGY COMING OUT OF THE 4
CORNERS REGION WITH POTENTIAL FOR PANHANDLE HOOK SYSTEM THAT COULD
BRING ACCUMULATING SNOW JUST OUTSIDE THE PERIOD. POPS WERE INCREASED
SOME BUT KEPT IN CHC FOR AT LEAST SOME CONSISTENCY IN PRECIP ON THE
FRONT ITSELF. TRAVEL INTERESTS OVER THE HOLIDAYS SHOULD MONITOR THE
LATEST FORECASTS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 102 AM EST WED DEC 17 2014

ONE LAST AREA OF LIGHT PRECIPITATION WILL CONTINUE TO MOVE ACROSS
NORTHERN INDIANA EARLY IN THE TAF PERIOD. A RAIN/SNOW MIX WILL
RAPIDLY CHANGE TO ALL SNOW BEFORE ENDING. A BRIEF IFR CIG AT FT
WAYNE IS POSSIBLE BEFORE THE PRECIPITATION ENDS. OTHERWISE...MVFR
CIGS SHOULD PERSIST THROUGH THE TAF PERIOD AS THE UPPER LOW
LINGERS OVER THE REGION WITH PLENTY OF MVFR CLOUDS UPSTREAM.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR LMZ043-046.

&&

$$

UPDATE...MARSILI
SYNOPSIS...MARSILI/SKIPPER
SHORT TERM...STEINWEDEL
LONG TERM...FISHER
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA








000
FXUS63 KIWX 170238
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
938 PM EST TUE DEC 16 2014

.SYNOPSIS...
ISSUED AT 647 PM EST TUE DEC 16 2014

A COUPLE OF UPPER LEVEL SHORT WAVES TRACKING THROUGH THE SOUTHERN
GREAT LAKES REGION WILL CONTINUE TO PROVIDE SOME SCATTERED LIGHT
RAIN SHOWERS OR PATCHY DRIZZLE THIS EVENING. ISOLATED TO SCATTERED
LAKE EFFECT SNOW SHOWERS ARE POSSIBLE LATE TONIGHT INTO
WEDNESDAY...MAINLY ACROSS SOUTHERN LOWER MICHIGAN AND FAR NORTHERN
INDIANA...BUT NO SNOW ACCUMULATION IS EXPECTED. LOW TEMPERATURES
TONIGHT WILL RANGE FROM THE MID 20S ACROSS NORTHEAST ILLINOIS...TO
THE LOWER 30S ACROSS NORTHWEST OHIO. HIGH TEMPERATURES ON
WEDNESDAY WILL REACH INTO THE LOWER TO MID 30S.

&&

.UPDATE...
ISSUED AT 931 PM EST TUE DEC 16 2014

PRECIP COVERAGE IS EXPECTED TO DIMINISH OVER THE NEXT FEW HOURS AS
UPPER VORT LOBE ACROSS SOUTHERN LAKE MICHIGAN CONTINUES TO GET
SHEARED IN STRONG BACKGROUND DEFORMATION FLOW. THIS SHOULD LEAD TO
INCREASING SYNOPTIC SCALE SUBSIDENCE OVERNIGHT...WITH REMAINING
PRECIP AFTER 06Z CONFINED TO LIGHT LAKE EFFECT. LAKE EFFECT SETUP STILL
APPEARS TO BE QUITE UNFAVORABLE GIVEN DRY MID LEVEL
PROFILES/SUBSIDENCE...MARGINAL SATURATION AT DEPTHS SUPPORTIVE OF
ICE INTRODUCTION FOR -SHSN...AND LIMITING WESTERLY FETCH. STILL
SOME CHANCE FOR SOME PATCHY LIGHT FREEZING DRIZZLE IN ASSOCIATION
WITH THIS LAKE EFFECT PRECIP...BUT HAVE OPTED TO CONTINUE TO OMIT
THIS MENTION WITH LOW CONFIDENCE OF OCCURRENCE.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 324 PM EST TUE DEC 16 2014

AFTERNOON WATER VAPOR SHOWS SMALLER SCALE VORT MAXES (ONE NEAR THE
IN/OH BORDER AND ANOTHER OVER CENTRAL LAKE MI) EMBEDDED IN PARENT
GREAT LAKES MID-UPPER LEVEL CIRCULATION/OCCLUSION...WITH A
SEPARATE NORTHERN STREAM SHORTWAVE DROPPING SE INTO THE UPPER
MIDWEST. AT THE SFC (19Z)...THERE IS A 1005 MB SFC LOW CENTERED
OVER SE LOWER MI... WITH A COLD FRONT EXTENDING SW INTO SW LOWER
MI AND WESTERN INDIANA. SCT SHOWERS/DRIZZLE ACCOMPANYING THE
CDFNT/MOIST CYCLONIC FLOW AND MORE ORGANIZED AREA OF LIGHT RAIN
TIED TO IMPULSE NOW WORKING INTO WESTERN OH WILL CONTINUE TO PUSH
EAST RESULTING IN A DOWNTREND IN SHOWER/DRIZZLE COVERAGE THIS
EVENING. ANY LINGERING PCPN COULD END AS A FEW SNOW SHOWERS/SNIZZLE
ACROSS THE NORTH LATE THIS EVENING AS COLDER AIR BEGINS TO
UNDERCUT.

THE AFOREMENTIONED NORTHERN STREAM TROUGH WILL ELONGATE INTO THE
CENTRAL LAKES AND BECOME ORIENTED MORE WEST TO EAST OVERNIGHT INTO
WEDNESDAY. THIS FEATURE WILL HELP KICK THE LOWER LAKES SYSTEM OUT
OF THE AREA WITH DRIER/SUBSIDENT AIR ADVECTING IN ON THE SOUTHERN
FLANK OF A STRUNG OUT CENTRAL LAKES MID LEVEL DEFORMATION AXIS.
THE RESULT WILL BE A TREND TOWARD DRY/COLDER/SOMEWHAT BREEZY
CONDITIONS IN WEAK CAA REGIME. VEERED WNW FLOW WITHIN BOUNDARY
LAYER WITH LAKE-8H DIFFERENTIALS REACHING THE LOW TEENS WILL KEEP
LOW CLOUDS AROUND INTO TOMORROW. MARGINAL DELTA T`S/INVERSION
HEIGHTS AND SHALLOW MOISTURE PROFILES SUPPORT INHERITED LOW-MID
CHC POPS FOR SCT LAKE EFFECT SNOW SHOWERS/FLURRIES AND LITTLE/NO
ACCUMS. QUICK PERUSAL OF FCST SOUNDINGS/XSECTIONS SHOWING BULK OF
MOISTURE BELOW THE -12C LAYER ALSO CONCERNING FOR ANY ICE
PRODUCTION AND DZ/FZDZ POTENTIAL. WILL HOLD OFF ON ADDING DZ/FZDZ
IN THE FCST GIVEN LOW PROBABILITY OF OCCURRENCE. DRY AND FEELING
MUCH MORE LIKE MID DECEMBER OTHERWISE TOMORROW.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 324 PM EST TUE DEC 16 2014

INCREASINGLY ACTIVE PATTERN UNFOLDING FOR THE LONG TERM AND BEYOND.
FOCUS WILL BE ON 2 SYSTEMS FOR THE CURRENT PERIOD...ONE FOR THIS
WEEKEND AND THE OTHER ARRIVING PRIOR TO CHRISTMAS.

NW FLOW OFF LAKE MICHIGAN WILL PROVIDE INCREASED CLOUD COVER BUT
QUESTIONABLE IMPACTS IN TERMS OF PRECIPITATION AS COMBINATION OF
MARGINAL DELTA T`S...POTENTIAL FOR DRY AIR ENTRAINMENT AND LOW
INVERSION HEIGHTS ALL LEAD TO LESS THAN IDEAL CONDITIONS FOR
ACCUMULATING SNOWFALL. WILL LIKELY BE AT LEAST SCATTERED SNOW
SHOWERS AROUND...SO WILL MATCH UP WITH COVERAGE WORDING BUT HAVE
LITTLE/NO ACCUMULATIONS. LONGWAVE TROUGH MOVING ACROSS THE
WESTERN STATES WILL DIG INTO TEXAS AND PICK UP A PIECE OF ENERGY
COMING OUT OF THE 4 CORNERS AREA. ALL SIGNS CONTINUE TO POINT
TOWARDS A SUPPRESSED SOLUTION WITH THE LOW TRACKING FROM THE GULF OF
MEXICO NE TO ALONG THE APPALACHIANS SAT/SAT NGT. WHILE PLENTY OF
MSTR WILL EXIST WITH THE SYSTEM...FURTHER EAST TRACK WILL KEEP THE
AREA FROM SEEING ANY MAJOR IMPACTS WITH MAYBE SOME LIGHT
SNOW/FLURRIES.

HIGH PRESSURE WILL BUILD IN FOR SUNDAY INTO MONDAY TO BRING
SEASONABLE TEMPERATURES AND DRY CONDITIONS. FROM THIS POINT
FORWARD...MUCH MORE VOLATILE PATTERN SETS UP WITH NEXT PIECE OF
ENERGY (CLIPPER TYPE) DIVING OUT OF THE PLAINS INTO THE NORTHERN
GREAT LAKES. A COLD FRONT WILL EXTEND FROM THE LOW AND BRING A
CHANCE FOR SNOW SHOWERS TO THE AREA AT THE END OF THE PERIOD. EXACT
COVERAGE AND IMPACTS ARE STILL UNCERTAIN WITH GFS DEEPENING THE SFC
LOW OVER NE WISCONSIN BY TUESDAY AFTERNOON VS MAIN LOW STILL UP BY
THE ARROWHEAD OF MINNESOTA ON THE ECMWF. CONFIDENCE LOW IN EVOLUTION
OF THIS SYSTEM AND ALSO ADDITIONAL ENERGY COMING OUT OF THE 4
CORNERS REGION WITH POTENTIAL FOR PANHANDLE HOOK SYSTEM THAT COULD
BRING ACCUMULATING SNOW JUST OUTSIDE THE PERIOD. POPS WERE INCREASED
SOME BUT KEPT IN CHC FOR AT LEAST SOME CONSISTENCY IN PRECIP ON THE
FRONT ITSELF. TRAVEL INTERESTS OVER THE HOLIDAYS SHOULD MONITOR THE
LATEST FORECASTS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 647 PM EST TUE DEC 16 2014

SCATTERED LIGHT RAIN SHOWERS ALONG WITH SOME PATCHY DRIZZLE WILL
CONTINUE TO AFFECT TERMINALS THROUGH AROUND 03Z. BY LATE EVENING
INTO THE OVERNIGHT SYNOPTIC SCALE SUBSIDENCE WILL BECOME MORE
ESTABLISHED RESULTING IN DIMINISHING PRECIPITATION COVERAGE. SOME
LAKE EFFECT SNOW SHOWERS ARE POSSIBLE LATE TONIGHT INTO
WEDNESDAY...BUT LOW LEVEL WINDS SHOULD FAVOR THIS CHANCE TO THE
NORTH OF KSBN. IFR CIGS TO START THE PERIOD SHOULD IMPROVE TO MVFR
LATE EVENING OR THE EARLY PORTIONS OF THE OVERNIGHT AS DRIER LOW
LEVEL AIR ADVECTS ACROSS NORTHERN INDIANA. STRENGTHENING
SUBSIDENCE OVERNIGHT AND LOWERING INVERSION WILL KEEP IN LOW
CLOUDS HOWEVER THROUGH MUCH OF THIS PERIOD...WITH MVFR CIGS
EXPECTED TO CONTINUE INTO A GOOD PART OF WEDNESDAY. LOW LEVEL COLD
ADVECTION AND A MODERATELY STRONG PRESSURE GRADIENT WILL ALLOW FOR
WEST WINDS OF 10 TO 15 KNOTS THROUGH THE PERIOD...WITH GUSTS TO
AROUND 20 KNOTS.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST THURSDAY FOR LMZ043-046.

&&

$$

UPDATE...MARSILI
SYNOPSIS...MARSILI
SHORT TERM...STEINWEDEL
LONG TERM...FISHER
AVIATION...MARSILI


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA







000
FXUS63 KIWX 170023
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
723 PM EST TUE DEC 16 2014

.SYNOPSIS...
ISSUED AT 647 PM EST TUE DEC 16 2014

A COUPLE OF UPPER LEVEL SHORT WAVES TRACKING THROUGH THE SOUTHERN
GREAT LAKES REGION WILL CONTINUE TO PROVIDE SOME SCATTERED LIGHT
RAIN SHOWERS OR PATCHY DRIZZLE THIS EVENING. ISOLATED TO SCATTERED
LAKE EFFECT SNOW SHOWERS ARE POSSIBLE LATE TONIGHT INTO
WEDNESDAY...MAINLY ACROSS SOUTHERN LOWER MICHIGAN AND FAR NORTHERN
INDIANA...BUT NO SNOW ACCUMULATION IS EXPECTED. LOW TEMPERATURES
TONIGHT WILL RANGE FROM THE MID 20S ACROSS NORTHEAST ILLINOIS...TO
THE LOWER 30S ACROSS NORTHWEST OHIO. HIGH TEMPERATURES ON
WEDNESDAY WILL REACH INTO THE LOWER TO MID 30S.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 324 PM EST TUE DEC 16 2014

AFTERNOON WATER VAPOR SHOWS SMALLER SCALE VORT MAXES (ONE NEAR THE
IN/OH BORDER AND ANOTHER OVER CENTRAL LAKE MI) EMBEDDED IN PARENT
GREAT LAKES MID-UPPER LEVEL CIRCULATION/OCCLUSION...WITH A
SEPARATE NORTHERN STREAM SHORTWAVE DROPPING SE INTO THE UPPER
MIDWEST. AT THE SFC (19Z)...THERE IS A 1005 MB SFC LOW CENTERED
OVER SE LOWER MI... WITH A COLD FRONT EXTENDING SW INTO SW LOWER
MI AND WESTERN INDIANA. SCT SHOWERS/DRIZZLE ACCOMPANYING THE
CDFNT/MOIST CYCLONIC FLOW AND MORE ORGANIZED AREA OF LIGHT RAIN
TIED TO IMPULSE NOW WORKING INTO WESTERN OH WILL CONTINUE TO PUSH
EAST RESULTING IN A DOWNTREND IN SHOWER/DRIZZLE COVERAGE THIS
EVENING. ANY LINGERING PCPN COULD END AS A FEW SNOW SHOWERS/SNIZZLE
ACROSS THE NORTH LATE THIS EVENING AS COLDER AIR BEGINS TO
UNDERCUT.

THE AFOREMENTIONED NORTHERN STREAM TROUGH WILL ELONGATE INTO THE
CENTRAL LAKES AND BECOME ORIENTED MORE WEST TO EAST OVERNIGHT INTO
WEDNESDAY. THIS FEATURE WILL HELP KICK THE LOWER LAKES SYSTEM OUT
OF THE AREA WITH DRIER/SUBSIDENT AIR ADVECTING IN ON THE SOUTHERN
FLANK OF A STRUNG OUT CENTRAL LAKES MID LEVEL DEFORMATION AXIS.
THE RESULT WILL BE A TREND TOWARD DRY/COLDER/SOMEWHAT BREEZY
CONDITIONS IN WEAK CAA REGIME. VEERED WNW FLOW WITHIN BOUNDARY
LAYER WITH LAKE-8H DIFFERENTIALS REACHING THE LOW TEENS WILL KEEP
LOW CLOUDS AROUND INTO TOMORROW. MARGINAL DELTA T`S/INVERSION
HEIGHTS AND SHALLOW MOISTURE PROFILES SUPPORT INHERITED LOW-MID
CHC POPS FOR SCT LAKE EFFECT SNOW SHOWERS/FLURRIES AND LITTLE/NO
ACCUMS. QUICK PERUSAL OF FCST SOUNDINGS/XSECTIONS SHOWING BULK OF
MOISTURE BELOW THE -12C LAYER ALSO CONCERNING FOR ANY ICE
PRODUCTION AND DZ/FZDZ POTENTIAL. WILL HOLD OFF ON ADDING DZ/FZDZ
IN THE FCST GIVEN LOW PROBABILITY OF OCCURRENCE. DRY AND FEELING
MUCH MORE LIKE MID DECEMBER OTHERWISE TOMORROW.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 324 PM EST TUE DEC 16 2014

INCREASINGLY ACTIVE PATTERN UNFOLDING FOR THE LONG TERM AND BEYOND.
FOCUS WILL BE ON 2 SYSTEMS FOR THE CURRENT PERIOD...ONE FOR THIS
WEEKEND AND THE OTHER ARRIVING PRIOR TO CHRISTMAS.

NW FLOW OFF LAKE MICHIGAN WILL PROVIDE INCREASED CLOUD COVER BUT
QUESTIONABLE IMPACTS IN TERMS OF PRECIPITATION AS COMBINATION OF
MARGINAL DELTA T`S...POTENTIAL FOR DRY AIR ENTRAINMENT AND LOW
INVERSION HEIGHTS ALL LEAD TO LESS THAN IDEAL CONDITIONS FOR
ACCUMULATING SNOWFALL. WILL LIKELY BE AT LEAST SCATTERED SNOW
SHOWERS AROUND...SO WILL MATCH UP WITH COVERAGE WORDING BUT HAVE
LITTLE/NO ACCUMULATIONS. LONGWAVE TROUGH MOVING ACROSS THE
WESTERN STATES WILL DIG INTO TEXAS AND PICK UP A PIECE OF ENERGY
COMING OUT OF THE 4 CORNERS AREA. ALL SIGNS CONTINUE TO POINT
TOWARDS A SUPPRESSED SOLUTION WITH THE LOW TRACKING FROM THE GULF OF
MEXICO NE TO ALONG THE APPALACHIANS SAT/SAT NGT. WHILE PLENTY OF
MSTR WILL EXIST WITH THE SYSTEM...FURTHER EAST TRACK WILL KEEP THE
AREA FROM SEEING ANY MAJOR IMPACTS WITH MAYBE SOME LIGHT
SNOW/FLURRIES.

HIGH PRESSURE WILL BUILD IN FOR SUNDAY INTO MONDAY TO BRING
SEASONABLE TEMPERATURES AND DRY CONDITIONS. FROM THIS POINT
FORWARD...MUCH MORE VOLATILE PATTERN SETS UP WITH NEXT PIECE OF
ENERGY (CLIPPER TYPE) DIVING OUT OF THE PLAINS INTO THE NORTHERN
GREAT LAKES. A COLD FRONT WILL EXTEND FROM THE LOW AND BRING A
CHANCE FOR SNOW SHOWERS TO THE AREA AT THE END OF THE PERIOD. EXACT
COVERAGE AND IMPACTS ARE STILL UNCERTAIN WITH GFS DEEPENING THE SFC
LOW OVER NE WISCONSIN BY TUESDAY AFTERNOON VS MAIN LOW STILL UP BY
THE ARROWHEAD OF MINNESOTA ON THE ECMWF. CONFIDENCE LOW IN EVOLUTION
OF THIS SYSTEM AND ALSO ADDITIONAL ENERGY COMING OUT OF THE 4
CORNERS REGION WITH POTENTIAL FOR PANHANDLE HOOK SYSTEM THAT COULD
BRING ACCUMULATING SNOW JUST OUTSIDE THE PERIOD. POPS WERE INCREASED
SOME BUT KEPT IN CHC FOR AT LEAST SOME CONSISTENCY IN PRECIP ON THE
FRONT ITSELF. TRAVEL INTERESTS OVER THE HOLIDAYS SHOULD MONITOR THE
LATEST FORECASTS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 647 PM EST TUE DEC 16 2014

SCATTERED LIGHT RAIN SHOWERS ALONG WITH SOME PATCHY DRIZZLE WILL
CONTINUE TO AFFECT TERMINALS THROUGH AROUND 03Z. BY LATE EVENING
INTO THE OVERNIGHT SYNOPTIC SCALE SUBSIDENCE WILL BECOME MORE
ESTABLISHED RESULTING IN DIMINISHING PRECIPITATION COVERAGE. SOME
LAKE EFFECT SNOW SHOWERS ARE POSSIBLE LATE TONIGHT INTO
WEDNESDAY...BUT LOW LEVEL WINDS SHOULD FAVOR THIS CHANCE TO THE
NORTH OF KSBN. IFR CIGS TO START THE PERIOD SHOULD IMPROVE TO MVFR
LATE EVENING OR THE EARLY PORTIONS OF THE OVERNIGHT AS DRIER LOW
LEVEL AIR ADVECTS ACROSS NORTHERN INDIANA. STRENGTHENING
SUBSIDENCE OVERNIGHT AND LOWERING INVERSION WILL KEEP IN LOW
CLOUDS HOWEVER THROUGH MUCH OF THIS PERIOD...WITH MVFR CIGS
EXPECTED TO CONTINUE INTO A GOOD PART OF WEDNESDAY. LOW LEVEL COLD
ADVECTION AND A MODERATELY STRONG PRESSURE GRADIENT WILL ALLOW FOR
WEST WINDS OF 10 TO 15 KNOTS THROUGH THE PERIOD...WITH GUSTS TO
AROUND 20 KNOTS.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...MARSILI
SHORT TERM...STEINWEDEL
LONG TERM...FISHER
AVIATION...MARSILI


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA








000
FXUS63 KIWX 170023
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
723 PM EST TUE DEC 16 2014

.SYNOPSIS...
ISSUED AT 647 PM EST TUE DEC 16 2014

A COUPLE OF UPPER LEVEL SHORT WAVES TRACKING THROUGH THE SOUTHERN
GREAT LAKES REGION WILL CONTINUE TO PROVIDE SOME SCATTERED LIGHT
RAIN SHOWERS OR PATCHY DRIZZLE THIS EVENING. ISOLATED TO SCATTERED
LAKE EFFECT SNOW SHOWERS ARE POSSIBLE LATE TONIGHT INTO
WEDNESDAY...MAINLY ACROSS SOUTHERN LOWER MICHIGAN AND FAR NORTHERN
INDIANA...BUT NO SNOW ACCUMULATION IS EXPECTED. LOW TEMPERATURES
TONIGHT WILL RANGE FROM THE MID 20S ACROSS NORTHEAST ILLINOIS...TO
THE LOWER 30S ACROSS NORTHWEST OHIO. HIGH TEMPERATURES ON
WEDNESDAY WILL REACH INTO THE LOWER TO MID 30S.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 324 PM EST TUE DEC 16 2014

AFTERNOON WATER VAPOR SHOWS SMALLER SCALE VORT MAXES (ONE NEAR THE
IN/OH BORDER AND ANOTHER OVER CENTRAL LAKE MI) EMBEDDED IN PARENT
GREAT LAKES MID-UPPER LEVEL CIRCULATION/OCCLUSION...WITH A
SEPARATE NORTHERN STREAM SHORTWAVE DROPPING SE INTO THE UPPER
MIDWEST. AT THE SFC (19Z)...THERE IS A 1005 MB SFC LOW CENTERED
OVER SE LOWER MI... WITH A COLD FRONT EXTENDING SW INTO SW LOWER
MI AND WESTERN INDIANA. SCT SHOWERS/DRIZZLE ACCOMPANYING THE
CDFNT/MOIST CYCLONIC FLOW AND MORE ORGANIZED AREA OF LIGHT RAIN
TIED TO IMPULSE NOW WORKING INTO WESTERN OH WILL CONTINUE TO PUSH
EAST RESULTING IN A DOWNTREND IN SHOWER/DRIZZLE COVERAGE THIS
EVENING. ANY LINGERING PCPN COULD END AS A FEW SNOW SHOWERS/SNIZZLE
ACROSS THE NORTH LATE THIS EVENING AS COLDER AIR BEGINS TO
UNDERCUT.

THE AFOREMENTIONED NORTHERN STREAM TROUGH WILL ELONGATE INTO THE
CENTRAL LAKES AND BECOME ORIENTED MORE WEST TO EAST OVERNIGHT INTO
WEDNESDAY. THIS FEATURE WILL HELP KICK THE LOWER LAKES SYSTEM OUT
OF THE AREA WITH DRIER/SUBSIDENT AIR ADVECTING IN ON THE SOUTHERN
FLANK OF A STRUNG OUT CENTRAL LAKES MID LEVEL DEFORMATION AXIS.
THE RESULT WILL BE A TREND TOWARD DRY/COLDER/SOMEWHAT BREEZY
CONDITIONS IN WEAK CAA REGIME. VEERED WNW FLOW WITHIN BOUNDARY
LAYER WITH LAKE-8H DIFFERENTIALS REACHING THE LOW TEENS WILL KEEP
LOW CLOUDS AROUND INTO TOMORROW. MARGINAL DELTA T`S/INVERSION
HEIGHTS AND SHALLOW MOISTURE PROFILES SUPPORT INHERITED LOW-MID
CHC POPS FOR SCT LAKE EFFECT SNOW SHOWERS/FLURRIES AND LITTLE/NO
ACCUMS. QUICK PERUSAL OF FCST SOUNDINGS/XSECTIONS SHOWING BULK OF
MOISTURE BELOW THE -12C LAYER ALSO CONCERNING FOR ANY ICE
PRODUCTION AND DZ/FZDZ POTENTIAL. WILL HOLD OFF ON ADDING DZ/FZDZ
IN THE FCST GIVEN LOW PROBABILITY OF OCCURRENCE. DRY AND FEELING
MUCH MORE LIKE MID DECEMBER OTHERWISE TOMORROW.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 324 PM EST TUE DEC 16 2014

INCREASINGLY ACTIVE PATTERN UNFOLDING FOR THE LONG TERM AND BEYOND.
FOCUS WILL BE ON 2 SYSTEMS FOR THE CURRENT PERIOD...ONE FOR THIS
WEEKEND AND THE OTHER ARRIVING PRIOR TO CHRISTMAS.

NW FLOW OFF LAKE MICHIGAN WILL PROVIDE INCREASED CLOUD COVER BUT
QUESTIONABLE IMPACTS IN TERMS OF PRECIPITATION AS COMBINATION OF
MARGINAL DELTA T`S...POTENTIAL FOR DRY AIR ENTRAINMENT AND LOW
INVERSION HEIGHTS ALL LEAD TO LESS THAN IDEAL CONDITIONS FOR
ACCUMULATING SNOWFALL. WILL LIKELY BE AT LEAST SCATTERED SNOW
SHOWERS AROUND...SO WILL MATCH UP WITH COVERAGE WORDING BUT HAVE
LITTLE/NO ACCUMULATIONS. LONGWAVE TROUGH MOVING ACROSS THE
WESTERN STATES WILL DIG INTO TEXAS AND PICK UP A PIECE OF ENERGY
COMING OUT OF THE 4 CORNERS AREA. ALL SIGNS CONTINUE TO POINT
TOWARDS A SUPPRESSED SOLUTION WITH THE LOW TRACKING FROM THE GULF OF
MEXICO NE TO ALONG THE APPALACHIANS SAT/SAT NGT. WHILE PLENTY OF
MSTR WILL EXIST WITH THE SYSTEM...FURTHER EAST TRACK WILL KEEP THE
AREA FROM SEEING ANY MAJOR IMPACTS WITH MAYBE SOME LIGHT
SNOW/FLURRIES.

HIGH PRESSURE WILL BUILD IN FOR SUNDAY INTO MONDAY TO BRING
SEASONABLE TEMPERATURES AND DRY CONDITIONS. FROM THIS POINT
FORWARD...MUCH MORE VOLATILE PATTERN SETS UP WITH NEXT PIECE OF
ENERGY (CLIPPER TYPE) DIVING OUT OF THE PLAINS INTO THE NORTHERN
GREAT LAKES. A COLD FRONT WILL EXTEND FROM THE LOW AND BRING A
CHANCE FOR SNOW SHOWERS TO THE AREA AT THE END OF THE PERIOD. EXACT
COVERAGE AND IMPACTS ARE STILL UNCERTAIN WITH GFS DEEPENING THE SFC
LOW OVER NE WISCONSIN BY TUESDAY AFTERNOON VS MAIN LOW STILL UP BY
THE ARROWHEAD OF MINNESOTA ON THE ECMWF. CONFIDENCE LOW IN EVOLUTION
OF THIS SYSTEM AND ALSO ADDITIONAL ENERGY COMING OUT OF THE 4
CORNERS REGION WITH POTENTIAL FOR PANHANDLE HOOK SYSTEM THAT COULD
BRING ACCUMULATING SNOW JUST OUTSIDE THE PERIOD. POPS WERE INCREASED
SOME BUT KEPT IN CHC FOR AT LEAST SOME CONSISTENCY IN PRECIP ON THE
FRONT ITSELF. TRAVEL INTERESTS OVER THE HOLIDAYS SHOULD MONITOR THE
LATEST FORECASTS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 647 PM EST TUE DEC 16 2014

SCATTERED LIGHT RAIN SHOWERS ALONG WITH SOME PATCHY DRIZZLE WILL
CONTINUE TO AFFECT TERMINALS THROUGH AROUND 03Z. BY LATE EVENING
INTO THE OVERNIGHT SYNOPTIC SCALE SUBSIDENCE WILL BECOME MORE
ESTABLISHED RESULTING IN DIMINISHING PRECIPITATION COVERAGE. SOME
LAKE EFFECT SNOW SHOWERS ARE POSSIBLE LATE TONIGHT INTO
WEDNESDAY...BUT LOW LEVEL WINDS SHOULD FAVOR THIS CHANCE TO THE
NORTH OF KSBN. IFR CIGS TO START THE PERIOD SHOULD IMPROVE TO MVFR
LATE EVENING OR THE EARLY PORTIONS OF THE OVERNIGHT AS DRIER LOW
LEVEL AIR ADVECTS ACROSS NORTHERN INDIANA. STRENGTHENING
SUBSIDENCE OVERNIGHT AND LOWERING INVERSION WILL KEEP IN LOW
CLOUDS HOWEVER THROUGH MUCH OF THIS PERIOD...WITH MVFR CIGS
EXPECTED TO CONTINUE INTO A GOOD PART OF WEDNESDAY. LOW LEVEL COLD
ADVECTION AND A MODERATELY STRONG PRESSURE GRADIENT WILL ALLOW FOR
WEST WINDS OF 10 TO 15 KNOTS THROUGH THE PERIOD...WITH GUSTS TO
AROUND 20 KNOTS.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...MARSILI
SHORT TERM...STEINWEDEL
LONG TERM...FISHER
AVIATION...MARSILI


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA







000
FXUS63 KIWX 162024
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
324 PM EST TUE DEC 16 2014

.SYNOPSIS...
ISSUED AT 1044 AM EST TUE DEC 16 2014

A LOW PRESSURE SYSTEM MOVING THROUGH THE REGION IS BRINGING RAIN
TO THE AREA. AS THIS SYSTEM BEGINS TO PULL AWAY TONIGHT THE RAIN
WILL BE CHANGING OVER TO SNOW IN NORTHERN INDIANA AND SOUTHERN
MICHIGAN AND ENDING ELSEWHERE. THE HIGH TEMPERATURES TODAY WILL BE
IN THE MIDDLE 40S. LOWS TONIGHT WILL BE IN THE UPPER 20S IN THE
NORTH TO AROUND 30 NEAR THE OHIO RIVER.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 324 PM EST TUE DEC 16 2014

AFTERNOON WATER VAPOR SHOWS SMALLER SCALE VORT MAXES (ONE NEAR THE
IN/OH BORDER AND ANOTHER OVER CENTRAL LAKE MI) EMBEDDED IN PARENT
GREAT LAKES MID-UPPER LEVEL CIRCULATION/OCCLUSION...WITH A
SEPARATE NORTHERN STREAM SHORTWAVE DROPPING SE INTO THE UPPER
MIDWEST. AT THE SFC (19Z)...THERE IS A 1005 MB SFC LOW CENTERED
OVER SE LOWER MI... WITH A COLD FRONT EXTENDING SW INTO SW LOWER
MI AND WESTERN INDIANA. SCT SHOWERS/DRIZZLE ACCOMPANYING THE
CDFNT/MOIST CYCLONIC FLOW AND MORE ORGANIZED AREA OF LIGHT RAIN
TIED TO IMPULSE NOW WORKING INTO WESTERN OH WILL CONTINUE TO PUSH
EAST RESULTING IN A DOWNTREND IN SHOWER/DRIZZLE COVERAGE THIS
EVENING. ANY LINGERING PCPN COULD END AS A FEW SNOW SHOWERS/SNIZZLE
ACROSS THE NORTH LATE THIS EVENING AS COLDER AIR BEGINS TO
UNDERCUT.

THE AFOREMENTIONED NORTHERN STREAM TROUGH WILL ELONGATE INTO THE
CENTRAL LAKES AND BECOME ORIENTED MORE WEST TO EAST OVERNIGHT INTO
WEDNESDAY. THIS FEATURE WILL HELP KICK THE LOWER LAKES SYSTEM OUT
OF THE AREA WITH DRIER/SUBSIDENT AIR ADVECTING IN ON THE SOUTHERN
FLANK OF A STRUNG OUT CENTRAL LAKES MID LEVEL DEFORMATION AXIS.
THE RESULT WILL BE A TREND TOWARD DRY/COLDER/SOMEWHAT BREEZY
CONDITIONS IN WEAK CAA REGIME. VEERED WNW FLOW WITHIN BOUNDARY
LAYER WITH LAKE-8H DIFFERENTIALS REACHING THE LOW TEENS WILL KEEP
LOW CLOUDS AROUND INTO TOMORROW. MARGINAL DELTA T`S/INVERSION
HEIGHTS AND SHALLOW MOISTURE PROFILES SUPPORT INHERITED LOW-MID
CHC POPS FOR SCT LAKE EFFECT SNOW SHOWERS/FLURRIES AND LITTLE/NO
ACCUMS. QUICK PERUSAL OF FCST SOUNDINGS/XSECTIONS SHOWING BULK OF
MOISTURE BELOW THE -12C LAYER ALSO CONCERNING FOR ANY ICE
PRODUCTION AND DZ/FZDZ POTENTIAL. WILL HOLD OFF ON ADDING DZ/FZDZ
IN THE FCST GIVEN LOW PROBABILITY OF OCCURRENCE. DRY AND FEELING
MUCH MORE LIKE MID DECEMBER OTHERWISE TOMORROW.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 324 PM EST TUE DEC 16 2014

INCREASINGLY ACTIVE PATTERN UNFOLDING FOR THE LONG TERM AND BEYOND.
FOCUS WILL BE ON 2 SYSTEMS FOR THE CURRENT PERIOD...ONE FOR THIS
WEEKEND AND THE OTHER ARRIVING PRIOR TO CHRISTMAS.

NW FLOW OFF LAKE MICHIGAN WILL PROVIDE INCREASED CLOUD COVER BUT
QUESTIONABLE IMPACTS IN TERMS OF PRECIPITATION AS COMBINATION OF
MARGINAL DELTA T`S...POTENTIAL FOR DRY AIR ENTRAINMENT AND LOW
INVERSION HEIGHTS ALL LEAD TO LESS THAN IDEAL CONDITIONS FOR
ACCUMULATING SNOWFALL. WILL LIKELY BE AT LEAST SCATTERED SNOW
SHOWERS AROUND...SO WILL MATCH UP WITH COVERAGE WORDING BUT HAVE
LITTLE/NO ACCUMULATIONS. LONGWAVE TROUGH MOVING ACROSS THE
WESTERN STATES WILL DIG INTO TEXAS AND PICK UP A PIECE OF ENERGY
COMING OUT OF THE 4 CORNERS AREA. ALL SIGNS CONTINUE TO POINT
TOWARDS A SUPPRESSED SOLUTION WITH THE LOW TRACKING FROM THE GULF OF
MEXICO NE TO ALONG THE APPALACHIANS SAT/SAT NGT. WHILE PLENTY OF
MSTR WILL EXIST WITH THE SYSTEM...FURTHER EAST TRACK WILL KEEP THE
AREA FROM SEEING ANY MAJOR IMPACTS WITH MAYBE SOME LIGHT
SNOW/FLURRIES.

HIGH PRESSURE WILL BUILD IN FOR SUNDAY INTO MONDAY TO BRING
SEASONABLE TEMPERATURES AND DRY CONDITIONS. FROM THIS POINT
FORWARD...MUCH MORE VOLATILE PATTERN SETS UP WITH NEXT PIECE OF
ENERGY (CLIPPER TYPE) DIVING OUT OF THE PLAINS INTO THE NORTHERN
GREAT LAKES. A COLD FRONT WILL EXTEND FROM THE LOW AND BRING A
CHANCE FOR SNOW SHOWERS TO THE AREA AT THE END OF THE PERIOD. EXACT
COVERAGE AND IMPACTS ARE STILL UNCERTAIN WITH GFS DEEPENING THE SFC
LOW OVER NE WISCONSIN BY TUESDAY AFTERNOON VS MAIN LOW STILL UP BY
THE ARROWHEAD OF MINNESOTA ON THE ECMWF. CONFIDENCE LOW IN EVOLUTION
OF THIS SYSTEM AND ALSO ADDITIONAL ENERGY COMING OUT OF THE 4
CORNERS REGION WITH POTENTIAL FOR PANHANDLE HOOK SYSTEM THAT COULD
BRING ACCUMULATING SNOW JUST OUTSIDE THE PERIOD. POPS WERE INCREASED
SOME BUT KEPT IN CHC FOR AT LEAST SOME CONSISTENCY IN PRECIP ON THE
FRONT ITSELF. TRAVEL INTERESTS OVER THE HOLIDAYS SHOULD MONITOR THE
LATEST FORECASTS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1147 AM EST TUE DEC 16 2014

IFR CONDITIONS AND AREAS OF DRIZZLE/LIGHT RAIN THIS AFTERNOON WILL
GIVE WAY TO MAINLY MVFR/DRY CONDITIONS AT KSBN AND VFR/HIGH MVFR
AT KFWA WITH TIME TONIGHT AS DRIER AIR OVERSPREADS IN THE WAKE OF
A LOWER LAKES LOW PRESSURE SYSTEM AND ATTENDANT COLD FRONT. THERE
IS SOME CONCERN THAT LIGHT DRIZZLE/SNOW SHOWERS MAY IMPACT KSBN
OVERNIGHT INTO WEDNESDAY AS WINDS VEER WNW AND COLD ADVECTION
ENSUES. OPTED TO LEAVE ANY WX MENTION OUT OF THE FCST FOR NOW
GIVEN A VERY SHALLOW MOISTURE PROFILE AND MARGINAL LIFT.
OTHERWISE...EXPECT WINDS TO INCREASE LATER THIS AFTN/TONIGHT OUT
OF THE WEST.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...LOTHAMER
SHORT TERM...STEINWEDEL
LONG TERM...FISHER
AVIATION...STEINWEDEL


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA







000
FXUS63 KIWX 162024
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
324 PM EST TUE DEC 16 2014

.SYNOPSIS...
ISSUED AT 1044 AM EST TUE DEC 16 2014

A LOW PRESSURE SYSTEM MOVING THROUGH THE REGION IS BRINGING RAIN
TO THE AREA. AS THIS SYSTEM BEGINS TO PULL AWAY TONIGHT THE RAIN
WILL BE CHANGING OVER TO SNOW IN NORTHERN INDIANA AND SOUTHERN
MICHIGAN AND ENDING ELSEWHERE. THE HIGH TEMPERATURES TODAY WILL BE
IN THE MIDDLE 40S. LOWS TONIGHT WILL BE IN THE UPPER 20S IN THE
NORTH TO AROUND 30 NEAR THE OHIO RIVER.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 324 PM EST TUE DEC 16 2014

AFTERNOON WATER VAPOR SHOWS SMALLER SCALE VORT MAXES (ONE NEAR THE
IN/OH BORDER AND ANOTHER OVER CENTRAL LAKE MI) EMBEDDED IN PARENT
GREAT LAKES MID-UPPER LEVEL CIRCULATION/OCCLUSION...WITH A
SEPARATE NORTHERN STREAM SHORTWAVE DROPPING SE INTO THE UPPER
MIDWEST. AT THE SFC (19Z)...THERE IS A 1005 MB SFC LOW CENTERED
OVER SE LOWER MI... WITH A COLD FRONT EXTENDING SW INTO SW LOWER
MI AND WESTERN INDIANA. SCT SHOWERS/DRIZZLE ACCOMPANYING THE
CDFNT/MOIST CYCLONIC FLOW AND MORE ORGANIZED AREA OF LIGHT RAIN
TIED TO IMPULSE NOW WORKING INTO WESTERN OH WILL CONTINUE TO PUSH
EAST RESULTING IN A DOWNTREND IN SHOWER/DRIZZLE COVERAGE THIS
EVENING. ANY LINGERING PCPN COULD END AS A FEW SNOW SHOWERS/SNIZZLE
ACROSS THE NORTH LATE THIS EVENING AS COLDER AIR BEGINS TO
UNDERCUT.

THE AFOREMENTIONED NORTHERN STREAM TROUGH WILL ELONGATE INTO THE
CENTRAL LAKES AND BECOME ORIENTED MORE WEST TO EAST OVERNIGHT INTO
WEDNESDAY. THIS FEATURE WILL HELP KICK THE LOWER LAKES SYSTEM OUT
OF THE AREA WITH DRIER/SUBSIDENT AIR ADVECTING IN ON THE SOUTHERN
FLANK OF A STRUNG OUT CENTRAL LAKES MID LEVEL DEFORMATION AXIS.
THE RESULT WILL BE A TREND TOWARD DRY/COLDER/SOMEWHAT BREEZY
CONDITIONS IN WEAK CAA REGIME. VEERED WNW FLOW WITHIN BOUNDARY
LAYER WITH LAKE-8H DIFFERENTIALS REACHING THE LOW TEENS WILL KEEP
LOW CLOUDS AROUND INTO TOMORROW. MARGINAL DELTA T`S/INVERSION
HEIGHTS AND SHALLOW MOISTURE PROFILES SUPPORT INHERITED LOW-MID
CHC POPS FOR SCT LAKE EFFECT SNOW SHOWERS/FLURRIES AND LITTLE/NO
ACCUMS. QUICK PERUSAL OF FCST SOUNDINGS/XSECTIONS SHOWING BULK OF
MOISTURE BELOW THE -12C LAYER ALSO CONCERNING FOR ANY ICE
PRODUCTION AND DZ/FZDZ POTENTIAL. WILL HOLD OFF ON ADDING DZ/FZDZ
IN THE FCST GIVEN LOW PROBABILITY OF OCCURRENCE. DRY AND FEELING
MUCH MORE LIKE MID DECEMBER OTHERWISE TOMORROW.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 324 PM EST TUE DEC 16 2014

INCREASINGLY ACTIVE PATTERN UNFOLDING FOR THE LONG TERM AND BEYOND.
FOCUS WILL BE ON 2 SYSTEMS FOR THE CURRENT PERIOD...ONE FOR THIS
WEEKEND AND THE OTHER ARRIVING PRIOR TO CHRISTMAS.

NW FLOW OFF LAKE MICHIGAN WILL PROVIDE INCREASED CLOUD COVER BUT
QUESTIONABLE IMPACTS IN TERMS OF PRECIPITATION AS COMBINATION OF
MARGINAL DELTA T`S...POTENTIAL FOR DRY AIR ENTRAINMENT AND LOW
INVERSION HEIGHTS ALL LEAD TO LESS THAN IDEAL CONDITIONS FOR
ACCUMULATING SNOWFALL. WILL LIKELY BE AT LEAST SCATTERED SNOW
SHOWERS AROUND...SO WILL MATCH UP WITH COVERAGE WORDING BUT HAVE
LITTLE/NO ACCUMULATIONS. LONGWAVE TROUGH MOVING ACROSS THE
WESTERN STATES WILL DIG INTO TEXAS AND PICK UP A PIECE OF ENERGY
COMING OUT OF THE 4 CORNERS AREA. ALL SIGNS CONTINUE TO POINT
TOWARDS A SUPPRESSED SOLUTION WITH THE LOW TRACKING FROM THE GULF OF
MEXICO NE TO ALONG THE APPALACHIANS SAT/SAT NGT. WHILE PLENTY OF
MSTR WILL EXIST WITH THE SYSTEM...FURTHER EAST TRACK WILL KEEP THE
AREA FROM SEEING ANY MAJOR IMPACTS WITH MAYBE SOME LIGHT
SNOW/FLURRIES.

HIGH PRESSURE WILL BUILD IN FOR SUNDAY INTO MONDAY TO BRING
SEASONABLE TEMPERATURES AND DRY CONDITIONS. FROM THIS POINT
FORWARD...MUCH MORE VOLATILE PATTERN SETS UP WITH NEXT PIECE OF
ENERGY (CLIPPER TYPE) DIVING OUT OF THE PLAINS INTO THE NORTHERN
GREAT LAKES. A COLD FRONT WILL EXTEND FROM THE LOW AND BRING A
CHANCE FOR SNOW SHOWERS TO THE AREA AT THE END OF THE PERIOD. EXACT
COVERAGE AND IMPACTS ARE STILL UNCERTAIN WITH GFS DEEPENING THE SFC
LOW OVER NE WISCONSIN BY TUESDAY AFTERNOON VS MAIN LOW STILL UP BY
THE ARROWHEAD OF MINNESOTA ON THE ECMWF. CONFIDENCE LOW IN EVOLUTION
OF THIS SYSTEM AND ALSO ADDITIONAL ENERGY COMING OUT OF THE 4
CORNERS REGION WITH POTENTIAL FOR PANHANDLE HOOK SYSTEM THAT COULD
BRING ACCUMULATING SNOW JUST OUTSIDE THE PERIOD. POPS WERE INCREASED
SOME BUT KEPT IN CHC FOR AT LEAST SOME CONSISTENCY IN PRECIP ON THE
FRONT ITSELF. TRAVEL INTERESTS OVER THE HOLIDAYS SHOULD MONITOR THE
LATEST FORECASTS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1147 AM EST TUE DEC 16 2014

IFR CONDITIONS AND AREAS OF DRIZZLE/LIGHT RAIN THIS AFTERNOON WILL
GIVE WAY TO MAINLY MVFR/DRY CONDITIONS AT KSBN AND VFR/HIGH MVFR
AT KFWA WITH TIME TONIGHT AS DRIER AIR OVERSPREADS IN THE WAKE OF
A LOWER LAKES LOW PRESSURE SYSTEM AND ATTENDANT COLD FRONT. THERE
IS SOME CONCERN THAT LIGHT DRIZZLE/SNOW SHOWERS MAY IMPACT KSBN
OVERNIGHT INTO WEDNESDAY AS WINDS VEER WNW AND COLD ADVECTION
ENSUES. OPTED TO LEAVE ANY WX MENTION OUT OF THE FCST FOR NOW
GIVEN A VERY SHALLOW MOISTURE PROFILE AND MARGINAL LIFT.
OTHERWISE...EXPECT WINDS TO INCREASE LATER THIS AFTN/TONIGHT OUT
OF THE WEST.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...LOTHAMER
SHORT TERM...STEINWEDEL
LONG TERM...FISHER
AVIATION...STEINWEDEL


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA








000
FXUS63 KIWX 161647
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1147 AM EST TUE DEC 16 2014

.SYNOPSIS...
ISSUED AT 1044 AM EST TUE DEC 16 2014

A LOW PRESSURE SYSTEM MOVING THROUGH THE REGION IS BRINGING RAIN
TO THE AREA. AS THIS SYSTEM BEGINS TO PULL AWAY TONIGHT THE RAIN
WILL BE CHANGING OVER TO SNOW IN NORTHERN INDIANA AND SOUTHERN
MICHIGAN AND ENDING ELSEWHERE. THE HIGH TEMPERATURES TODAY WILL BE
IN THE MIDDLE 40S. LOWS TONIGHT WILL BE IN THE UPPER 20S IN THE
NORTH TO AROUND 30 NEAR THE OHIO RIVER.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 418 AM EST TUE DEC 16 2014

AN UPPER LOW WAS OVER NORTHERN IL AND WILL TRACK EAST ACROSS FAR
NORTHERN INDIANA AND SOUTHERN LOWER MICHIGAN LATER TODAY. AN AREA
OF RAIN ASSOCIATED WITH A SHORT WAVE WILL MOVE ACROSS THE FORECAST
AREA EARLY TODAY. RADAR AND SURFACE REPORTS INDICATED ISOLATED
SLEET WAS MIXED IN WITH THE RAIN. ANY SLEET WILL BE BRIEF AND SHOULD
BE LOCAL AND SHOULD HAVE MINIMAL IMPACTS WITH SURFACE TEMPERATURES
AROUND 45 DEGREES. THE MAIN AREA OF LIFT WITH THE UPPER LOW IN
THE TROWAL WILL TRANSLATE NORTHEAST OUT OF THE AREA...ALLOWING
PRECIPITATION AMOUNTS TO BECOME LIGHT THIS AFTERNOON. THE REMAINING
PRECIPITATION WILL MIX WITH AND CHANGE TO SNOW TONIGHT AS COLDER
AIR SPREADS BACK OVER THE AREA...ALTHOUGH ONLY LIGHT AMOUNTS OF
SNOW ARE EXPECTED.

&&

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 418 AM EST TUE DEC 16 2014

ONLY MINOR VARIANCES WARRANTED FROM PRIOR FORECAST AND CORROBORATING
LATEST MODEL BLEND. CONTINUE UNIMPRESSED WRT LES RESPONSE MIDWEEK
GIVEN NOMINAL SATURATION DEPTH. 295 DEGREE CBL FLOW VEERS TO ABOUT
310 THROUGH WED/WED NIGHT...THOUGH LWR TEENS DIFFERENTIALS
GENERATING LTE 200 J/KG LAKE INDUCED CAPE WITH LK INDUCED EQL ONLY
TOPPING 4KFT WED AFTN/EVE. THEREAFTER...925-8H COLD POOL SHIFTS WELL
EWD THROUGH LWR GRTLKS/WRN PA BY DAYBREAK...PUTTING FINAL KIBOSH ON
ALREADY LACKLUSTER CONDITIONING. ADVANCE OF UPSTREAM NRN PLAINS/SRN
CANADA RIDGING POSES DIFFICULTY WRT CLOUD COVER AS DIRTY
RIDGE/TRAPPING SUBSIDENCE INVERSION AGAIN APPEARS PSBL THU/FRI.
MODELS TRENDS WRT EVOLUTION OF COMPLEX MULTI-EMBEDDED SHORTWAVE WEST
COAST TROF HAS BEEN DECIDEDLY SOUTHWARD SHUNT WRT SFC CYCLOGENESIS
FRI/SAT. COLLABORATIVELY REMOVED HIGH BIAS BLENDED POPS FRI
NIGHT...AND ONLY TOKEN LIGHT SNOW CHCS SAT...PERHAPS WITHIN LAGGED
INVERTED TROF WITHIN NRN DUMBBELL OF HEIGHT FALL CENTROID TRACKING
THROUGH SRN GRTLKS. NEXT SYSTEM TO WATCH APPEARS TO BE NRN STREAM
CLIPPER FOR POTNL LIGHT ACCUM ABOUT DY8.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1147 AM EST TUE DEC 16 2014

IFR CONDITIONS AND AREAS OF DRIZZLE/LIGHT RAIN THIS AFTERNOON WILL
GIVE WAY TO MAINLY MVFR/DRY CONDITIONS AT KSBN AND VFR/HIGH MVFR
AT KFWA WITH TIME TONIGHT AS DRIER AIR OVERSPREADS IN THE WAKE OF
A LOWER LAKES LOW PRESSURE SYSTEM AND ATTENDANT COLD FRONT. THERE
IS SOME CONCERN THAT LIGHT DRIZZLE/SNOW SHOWERS MAY IMPACT KSBN
OVERNIGHT INTO WEDNESDAY AS WINDS VEER WNW AND COLD ADVECTION
ENSUES. OPTED TO LEAVE ANY WX MENTION OUT OF THE FCST FOR NOW
GIVEN A VERY SHALLOW MOISTURE PROFILE AND MARGINAL LIFT.
OTHERWISE...EXPECT WINDS TO INCREASE LATER THIS AFTN/TONIGHT OUT
OF THE WEST.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 5 AM EST
     THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...LOTHAMER
SHORT TERM...SKIPPER
LONG TERM...MURPHY
AVIATION...STEINWEDEL


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA







000
FXUS63 KIWX 161604
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1104 AM EST TUE DEC 16 2014

.SYNOPSIS...
ISSUED AT 1044 AM EST TUE DEC 16 2014

A LOW PRESSURE SYSTEM MOVING THROUGH THE REGION IS BRINGING RAIN
TO THE AREA. AS THIS SYSTEM BEGINS TO PULL AWAY TONIGHT THE RAIN
WILL BE CHANGING OVER TO SNOW IN NORTHERN INDIANA AND SOUTHERN
MICHIGAN AND ENDING ELSEWHERE. THE HIGH TEMPERATURES TODAY WILL BE
IN THE MIDDLE 40S. LOWS TONIGHT WILL BE IN THE UPPER 20S IN THE
NORTH TO AROUND 30 NEAR THE OHIO RIVER.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 418 AM EST TUE DEC 16 2014

AN UPPER LOW WAS OVER NORTHERN IL AND WILL TRACK EAST ACROSS FAR
NORTHERN INDIANA AND SOUTHERN LOWER MICHIGAN LATER TODAY. AN AREA
OF RAIN ASSOCIATED WITH A SHORT WAVE WILL MOVE ACROSS THE FORECAST
AREA EARLY TODAY. RADAR AND SURFACE REPORTS INDICATED ISOLATED
SLEET WAS MIXED IN WITH THE RAIN. ANY SLEET WILL BE BRIEF AND SHOULD
BE LOCAL AND SHOULD HAVE MINIMAL IMPACTS WITH SURFACE TEMPERATURES
AROUND 45 DEGREES. THE MAIN AREA OF LIFT WITH THE UPPER LOW IN
THE TROWAL WILL TRANSLATE NORTHEAST OUT OF THE AREA...ALLOWING
PRECIPITATION AMOUNTS TO BECOME LIGHT THIS AFTERNOON. THE REMAINING
PRECIPITATION WILL MIX WITH AND CHANGE TO SNOW TONIGHT AS COLDER
AIR SPREADS BACK OVER THE AREA...ALTHOUGH ONLY LIGHT AMOUNTS OF
SNOW ARE EXPECTED.

&&

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 418 AM EST TUE DEC 16 2014

ONLY MINOR VARIANCES WARRANTED FROM PRIOR FORECAST AND CORROBORATING
LATEST MODEL BLEND. CONTINUE UNIMPRESSED WRT LES RESPONSE MIDWEEK
GIVEN NOMINAL SATURATION DEPTH. 295 DEGREE CBL FLOW VEERS TO ABOUT
310 THROUGH WED/WED NIGHT...THOUGH LWR TEENS DIFFERENTIALS
GENERATING LTE 200 J/KG LAKE INDUCED CAPE WITH LK INDUCED EQL ONLY
TOPPING 4KFT WED AFTN/EVE. THEREAFTER...925-8H COLD POOL SHIFTS WELL
EWD THROUGH LWR GRTLKS/WRN PA BY DAYBREAK...PUTTING FINAL KIBOSH ON
ALREADY LACKLUSTER CONDITIONING. ADVANCE OF UPSTREAM NRN PLAINS/SRN
CANADA RIDGING POSES DIFFICULTY WRT CLOUD COVER AS DIRTY
RIDGE/TRAPPING SUBSIDENCE INVERSION AGAIN APPEARS PSBL THU/FRI.
MODELS TRENDS WRT EVOLUTION OF COMPLEX MULTI-EMBEDDED SHORTWAVE WEST
COAST TROF HAS BEEN DECIDEDLY SOUTHWARD SHUNT WRT SFC CYCLOGENESIS
FRI/SAT. COLLABORATIVELY REMOVED HIGH BIAS BLENDED POPS FRI
NIGHT...AND ONLY TOKEN LIGHT SNOW CHCS SAT...PERHAPS WITHIN LAGGED
INVERTED TROF WITHIN NRN DUMBBELL OF HEIGHT FALL CENTROID TRACKING
THROUGH SRN GRTLKS. NEXT SYSTEM TO WATCH APPEARS TO BE NRN STREAM
CLIPPER FOR POTNL LIGHT ACCUM ABOUT DY8.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 556 AM EST TUE DEC 16 2014

THE CORE OF THE UPPER LOW WAS OVER NORTHEAST IL AND WILL TRACK
EAST ACROSS SOUTHERN LOWER MICHIGAN TODAY. AN AREA OF RAIN
ASSOCIATED WITH AN UPPER LEVEL SHORT WAVE WAS ACCOMPANIED BY LOW
CIGS AND VSBYS. THIS SYSTEM WILL KEEP LOW CLOUDS AND VSBYS OVER
THE TERMINALS EARLY IN THE TAF PERIOD. EXPECT LOW TO VERY LOW IFR
CONDITIONS EARLY THIS MORNING AS THE UPPER LEVEL SYSTEM MOVES OVER
THE AREA. SOME IMPROVEMENT IS LIKELY AS THE LOW MOVES EAST AND AS
DRIER AIR SPREADS ACROSS THE AREA NEAR THE END OF THE TAF PERIOD.
WINDS WILL INCREASE AS THE GRADIENT TIGHTENS.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 5 AM EST
     THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...LOTHAMER
SHORT TERM...SKIPPER
LONG TERM...MURPHY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA







000
FXUS63 KIWX 161604
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1104 AM EST TUE DEC 16 2014

.SYNOPSIS...
ISSUED AT 1044 AM EST TUE DEC 16 2014

A LOW PRESSURE SYSTEM MOVING THROUGH THE REGION IS BRINGING RAIN
TO THE AREA. AS THIS SYSTEM BEGINS TO PULL AWAY TONIGHT THE RAIN
WILL BE CHANGING OVER TO SNOW IN NORTHERN INDIANA AND SOUTHERN
MICHIGAN AND ENDING ELSEWHERE. THE HIGH TEMPERATURES TODAY WILL BE
IN THE MIDDLE 40S. LOWS TONIGHT WILL BE IN THE UPPER 20S IN THE
NORTH TO AROUND 30 NEAR THE OHIO RIVER.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 418 AM EST TUE DEC 16 2014

AN UPPER LOW WAS OVER NORTHERN IL AND WILL TRACK EAST ACROSS FAR
NORTHERN INDIANA AND SOUTHERN LOWER MICHIGAN LATER TODAY. AN AREA
OF RAIN ASSOCIATED WITH A SHORT WAVE WILL MOVE ACROSS THE FORECAST
AREA EARLY TODAY. RADAR AND SURFACE REPORTS INDICATED ISOLATED
SLEET WAS MIXED IN WITH THE RAIN. ANY SLEET WILL BE BRIEF AND SHOULD
BE LOCAL AND SHOULD HAVE MINIMAL IMPACTS WITH SURFACE TEMPERATURES
AROUND 45 DEGREES. THE MAIN AREA OF LIFT WITH THE UPPER LOW IN
THE TROWAL WILL TRANSLATE NORTHEAST OUT OF THE AREA...ALLOWING
PRECIPITATION AMOUNTS TO BECOME LIGHT THIS AFTERNOON. THE REMAINING
PRECIPITATION WILL MIX WITH AND CHANGE TO SNOW TONIGHT AS COLDER
AIR SPREADS BACK OVER THE AREA...ALTHOUGH ONLY LIGHT AMOUNTS OF
SNOW ARE EXPECTED.

&&

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 418 AM EST TUE DEC 16 2014

ONLY MINOR VARIANCES WARRANTED FROM PRIOR FORECAST AND CORROBORATING
LATEST MODEL BLEND. CONTINUE UNIMPRESSED WRT LES RESPONSE MIDWEEK
GIVEN NOMINAL SATURATION DEPTH. 295 DEGREE CBL FLOW VEERS TO ABOUT
310 THROUGH WED/WED NIGHT...THOUGH LWR TEENS DIFFERENTIALS
GENERATING LTE 200 J/KG LAKE INDUCED CAPE WITH LK INDUCED EQL ONLY
TOPPING 4KFT WED AFTN/EVE. THEREAFTER...925-8H COLD POOL SHIFTS WELL
EWD THROUGH LWR GRTLKS/WRN PA BY DAYBREAK...PUTTING FINAL KIBOSH ON
ALREADY LACKLUSTER CONDITIONING. ADVANCE OF UPSTREAM NRN PLAINS/SRN
CANADA RIDGING POSES DIFFICULTY WRT CLOUD COVER AS DIRTY
RIDGE/TRAPPING SUBSIDENCE INVERSION AGAIN APPEARS PSBL THU/FRI.
MODELS TRENDS WRT EVOLUTION OF COMPLEX MULTI-EMBEDDED SHORTWAVE WEST
COAST TROF HAS BEEN DECIDEDLY SOUTHWARD SHUNT WRT SFC CYCLOGENESIS
FRI/SAT. COLLABORATIVELY REMOVED HIGH BIAS BLENDED POPS FRI
NIGHT...AND ONLY TOKEN LIGHT SNOW CHCS SAT...PERHAPS WITHIN LAGGED
INVERTED TROF WITHIN NRN DUMBBELL OF HEIGHT FALL CENTROID TRACKING
THROUGH SRN GRTLKS. NEXT SYSTEM TO WATCH APPEARS TO BE NRN STREAM
CLIPPER FOR POTNL LIGHT ACCUM ABOUT DY8.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 556 AM EST TUE DEC 16 2014

THE CORE OF THE UPPER LOW WAS OVER NORTHEAST IL AND WILL TRACK
EAST ACROSS SOUTHERN LOWER MICHIGAN TODAY. AN AREA OF RAIN
ASSOCIATED WITH AN UPPER LEVEL SHORT WAVE WAS ACCOMPANIED BY LOW
CIGS AND VSBYS. THIS SYSTEM WILL KEEP LOW CLOUDS AND VSBYS OVER
THE TERMINALS EARLY IN THE TAF PERIOD. EXPECT LOW TO VERY LOW IFR
CONDITIONS EARLY THIS MORNING AS THE UPPER LEVEL SYSTEM MOVES OVER
THE AREA. SOME IMPROVEMENT IS LIKELY AS THE LOW MOVES EAST AND AS
DRIER AIR SPREADS ACROSS THE AREA NEAR THE END OF THE TAF PERIOD.
WINDS WILL INCREASE AS THE GRADIENT TIGHTENS.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 5 AM EST
     THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...LOTHAMER
SHORT TERM...SKIPPER
LONG TERM...MURPHY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA








000
FXUS63 KIWX 161604
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1104 AM EST TUE DEC 16 2014

.SYNOPSIS...
ISSUED AT 1044 AM EST TUE DEC 16 2014

A LOW PRESSURE SYSTEM MOVING THROUGH THE REGION IS BRINGING RAIN
TO THE AREA. AS THIS SYSTEM BEGINS TO PULL AWAY TONIGHT THE RAIN
WILL BE CHANGING OVER TO SNOW IN NORTHERN INDIANA AND SOUTHERN
MICHIGAN AND ENDING ELSEWHERE. THE HIGH TEMPERATURES TODAY WILL BE
IN THE MIDDLE 40S. LOWS TONIGHT WILL BE IN THE UPPER 20S IN THE
NORTH TO AROUND 30 NEAR THE OHIO RIVER.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 418 AM EST TUE DEC 16 2014

AN UPPER LOW WAS OVER NORTHERN IL AND WILL TRACK EAST ACROSS FAR
NORTHERN INDIANA AND SOUTHERN LOWER MICHIGAN LATER TODAY. AN AREA
OF RAIN ASSOCIATED WITH A SHORT WAVE WILL MOVE ACROSS THE FORECAST
AREA EARLY TODAY. RADAR AND SURFACE REPORTS INDICATED ISOLATED
SLEET WAS MIXED IN WITH THE RAIN. ANY SLEET WILL BE BRIEF AND SHOULD
BE LOCAL AND SHOULD HAVE MINIMAL IMPACTS WITH SURFACE TEMPERATURES
AROUND 45 DEGREES. THE MAIN AREA OF LIFT WITH THE UPPER LOW IN
THE TROWAL WILL TRANSLATE NORTHEAST OUT OF THE AREA...ALLOWING
PRECIPITATION AMOUNTS TO BECOME LIGHT THIS AFTERNOON. THE REMAINING
PRECIPITATION WILL MIX WITH AND CHANGE TO SNOW TONIGHT AS COLDER
AIR SPREADS BACK OVER THE AREA...ALTHOUGH ONLY LIGHT AMOUNTS OF
SNOW ARE EXPECTED.

&&

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 418 AM EST TUE DEC 16 2014

ONLY MINOR VARIANCES WARRANTED FROM PRIOR FORECAST AND CORROBORATING
LATEST MODEL BLEND. CONTINUE UNIMPRESSED WRT LES RESPONSE MIDWEEK
GIVEN NOMINAL SATURATION DEPTH. 295 DEGREE CBL FLOW VEERS TO ABOUT
310 THROUGH WED/WED NIGHT...THOUGH LWR TEENS DIFFERENTIALS
GENERATING LTE 200 J/KG LAKE INDUCED CAPE WITH LK INDUCED EQL ONLY
TOPPING 4KFT WED AFTN/EVE. THEREAFTER...925-8H COLD POOL SHIFTS WELL
EWD THROUGH LWR GRTLKS/WRN PA BY DAYBREAK...PUTTING FINAL KIBOSH ON
ALREADY LACKLUSTER CONDITIONING. ADVANCE OF UPSTREAM NRN PLAINS/SRN
CANADA RIDGING POSES DIFFICULTY WRT CLOUD COVER AS DIRTY
RIDGE/TRAPPING SUBSIDENCE INVERSION AGAIN APPEARS PSBL THU/FRI.
MODELS TRENDS WRT EVOLUTION OF COMPLEX MULTI-EMBEDDED SHORTWAVE WEST
COAST TROF HAS BEEN DECIDEDLY SOUTHWARD SHUNT WRT SFC CYCLOGENESIS
FRI/SAT. COLLABORATIVELY REMOVED HIGH BIAS BLENDED POPS FRI
NIGHT...AND ONLY TOKEN LIGHT SNOW CHCS SAT...PERHAPS WITHIN LAGGED
INVERTED TROF WITHIN NRN DUMBBELL OF HEIGHT FALL CENTROID TRACKING
THROUGH SRN GRTLKS. NEXT SYSTEM TO WATCH APPEARS TO BE NRN STREAM
CLIPPER FOR POTNL LIGHT ACCUM ABOUT DY8.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 556 AM EST TUE DEC 16 2014

THE CORE OF THE UPPER LOW WAS OVER NORTHEAST IL AND WILL TRACK
EAST ACROSS SOUTHERN LOWER MICHIGAN TODAY. AN AREA OF RAIN
ASSOCIATED WITH AN UPPER LEVEL SHORT WAVE WAS ACCOMPANIED BY LOW
CIGS AND VSBYS. THIS SYSTEM WILL KEEP LOW CLOUDS AND VSBYS OVER
THE TERMINALS EARLY IN THE TAF PERIOD. EXPECT LOW TO VERY LOW IFR
CONDITIONS EARLY THIS MORNING AS THE UPPER LEVEL SYSTEM MOVES OVER
THE AREA. SOME IMPROVEMENT IS LIKELY AS THE LOW MOVES EAST AND AS
DRIER AIR SPREADS ACROSS THE AREA NEAR THE END OF THE TAF PERIOD.
WINDS WILL INCREASE AS THE GRADIENT TIGHTENS.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 5 AM EST
     THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...LOTHAMER
SHORT TERM...SKIPPER
LONG TERM...MURPHY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA








000
FXUS63 KIWX 161057
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
557 AM EST TUE DEC 16 2014

.SYNOPSIS...
ISSUED AT 555 AM EST TUE DEC 15 2014

AN UPPER LEVEL DISTURBANCE AND LOW PRESSURE AREA WILL MOVE ACROSS
THE REGION ACCOMPANIED BY PERIODS OF RAIN THIS MORNING. LINGERING
RAIN SHOWERS WILL PERSIST INTO THIS AFTERNOON. THE PRECIPITATION
WILL MIX WITH SNOW AND THEN CHANGE TO ALL SNOW TONIGHT. SOME LIGHT
SNOW ACCUMULATIONS ARE POSSIBLE TONIGHT... ESPECIALLY OVER
NORTHWEST INDIANA AND FAR SOUTHWEST LOWER MICHIGAN. COLDER WEATHER
IS ON THE HORIZON FOR MID WEEK BEHIND THIS SYSTEM. HIGHS TODAY
SHOULD REACH THE MID AND UPPER 40S. LOWS TONIGHT WILL BE MAINLY IN
THE 20S. HIGHS WEDNESDAY WILL ONLY BE AROUND 30.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 418 AM EST TUE DEC 16 2014

AN UPPER LOW WAS OVER NORTHERN IL AND WILL TRACK EAST ACROSS FAR
NORTHERN INDIANA AND SOUTHERN LOWER MICHIGAN LATER TODAY. AN AREA
OF RAIN ASSOCIATED WITH A SHORT WAVE WILL MOVE ACROSS THE FORECAST
AREA EARLY TODAY. RADAR AND SURFACE REPORTS INDICATED ISOLATED
SLEET WAS MIXED IN WITH THE RAIN. ANY SLEET WILL BE BRIEF AND SHOULD
BE LOCAL AND SHOULD HAVE MINIMAL IMPACTS WITH SURFACE TEMPERATURES
AROUND 45 DEGREES. THE MAIN AREA OF LIFT WITH THE UPPER LOW IN
THE TROWAL WILL TRANSLATE NORTHEAST OUT OF THE AREA...ALLOWING
PRECIPITATION AMOUNTS TO BECOME LIGHT THIS AFTERNOON. THE REMAINING
PRECIPITATION WILL MIX WITH AND CHANGE TO SNOW TONIGHT AS COLDER
AIR SPREADS BACK OVER THE AREA...ALTHOUGH ONLY LIGHT AMOUNTS OF
SNOW ARE EXPECTED.

&&

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 418 AM EST TUE DEC 16 2014

ONLY MINOR VARIANCES WARRANTED FROM PRIOR FORECAST AND CORROBORATING
LATEST MODEL BLEND. CONTINUE UNIMPRESSED WRT LES RESPONSE MIDWEEK
GIVEN NOMINAL SATURATION DEPTH. 295 DEGREE CBL FLOW VEERS TO ABOUT
310 THROUGH WED/WED NIGHT...THOUGH LWR TEENS DIFFERENTIALS
GENERATING LTE 200 J/KG LAKE INDUCED CAPE WITH LK INDUCED EQL ONLY
TOPPING 4KFT WED AFTN/EVE. THEREAFTER...925-8H COLD POOL SHIFTS WELL
EWD THROUGH LWR GRTLKS/WRN PA BY DAYBREAK...PUTTING FINAL KIBOSH ON
ALREADY LACKLUSTER CONDITIONING. ADVANCE OF UPSTREAM NRN PLAINS/SRN
CANADA RIDGING POSES DIFFICULTY WRT CLOUD COVER AS DIRTY
RIDGE/TRAPPING SUBSIDENCE INVERSION AGAIN APPEARS PSBL THU/FRI.
MODELS TRENDS WRT EVOLUTION OF COMPLEX MULTI-EMBEDDED SHORTWAVE WEST
COAST TROF HAS BEEN DECIDEDLY SOUTHWARD SHUNT WRT SFC CYCLOGENESIS
FRI/SAT. COLLABORATIVELY REMOVED HIGH BIAS BLENDED POPS FRI
NIGHT...AND ONLY TOKEN LIGHT SNOW CHCS SAT...PERHAPS WITHIN LAGGED
INVERTED TROF WITHIN NRN DUMBBELL OF HEIGHT FALL CENTROID TRACKING
THROUGH SRN GRTLKS. NEXT SYSTEM TO WATCH APPEARS TO BE NRN STREAM
CLIPPER FOR POTNL LIGHT ACCUM ABOUT DY8.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 556 AM EST TUE DEC 16 2014

THE CORE OF THE UPPER LOW WAS OVER NORTHEAST IL AND WILL TRACK
EAST ACROSS SOUTHERN LOWER MICHIGAN TODAY. AN AREA OF RAIN
ASSOCIATED WITH AN UPPER LEVEL SHORT WAVE WAS ACCOMPANIED BY LOW
CIGS AND VSBYS. THIS SYSTEM WILL KEEP LOW CLOUDS AND VSBYS OVER
THE TERMINALS EARLY IN THE TAF PERIOD. EXPECT LOW TO VERY LOW IFR
CONDITIONS EARLY THIS MORNING AS THE UPPER LEVEL SYSTEM MOVES OVER
THE AREA. SOME IMPROVEMENT IS LIKELY AS THE LOW MOVES EAST AND AS
DRIER AIR SPREADS ACROSS THE AREA NEAR THE END OF THE TAF PERIOD.
WINDS WILL INCREASE AS THE GRADIENT TIGHTENS.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 5 AM EST
     THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...MARSILI/SKIPPER
SHORT TERM...SKIPPER
LONG TERM...MURPHY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA








000
FXUS63 KIWX 161057
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
557 AM EST TUE DEC 16 2014

.SYNOPSIS...
ISSUED AT 555 AM EST TUE DEC 15 2014

AN UPPER LEVEL DISTURBANCE AND LOW PRESSURE AREA WILL MOVE ACROSS
THE REGION ACCOMPANIED BY PERIODS OF RAIN THIS MORNING. LINGERING
RAIN SHOWERS WILL PERSIST INTO THIS AFTERNOON. THE PRECIPITATION
WILL MIX WITH SNOW AND THEN CHANGE TO ALL SNOW TONIGHT. SOME LIGHT
SNOW ACCUMULATIONS ARE POSSIBLE TONIGHT... ESPECIALLY OVER
NORTHWEST INDIANA AND FAR SOUTHWEST LOWER MICHIGAN. COLDER WEATHER
IS ON THE HORIZON FOR MID WEEK BEHIND THIS SYSTEM. HIGHS TODAY
SHOULD REACH THE MID AND UPPER 40S. LOWS TONIGHT WILL BE MAINLY IN
THE 20S. HIGHS WEDNESDAY WILL ONLY BE AROUND 30.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 418 AM EST TUE DEC 16 2014

AN UPPER LOW WAS OVER NORTHERN IL AND WILL TRACK EAST ACROSS FAR
NORTHERN INDIANA AND SOUTHERN LOWER MICHIGAN LATER TODAY. AN AREA
OF RAIN ASSOCIATED WITH A SHORT WAVE WILL MOVE ACROSS THE FORECAST
AREA EARLY TODAY. RADAR AND SURFACE REPORTS INDICATED ISOLATED
SLEET WAS MIXED IN WITH THE RAIN. ANY SLEET WILL BE BRIEF AND SHOULD
BE LOCAL AND SHOULD HAVE MINIMAL IMPACTS WITH SURFACE TEMPERATURES
AROUND 45 DEGREES. THE MAIN AREA OF LIFT WITH THE UPPER LOW IN
THE TROWAL WILL TRANSLATE NORTHEAST OUT OF THE AREA...ALLOWING
PRECIPITATION AMOUNTS TO BECOME LIGHT THIS AFTERNOON. THE REMAINING
PRECIPITATION WILL MIX WITH AND CHANGE TO SNOW TONIGHT AS COLDER
AIR SPREADS BACK OVER THE AREA...ALTHOUGH ONLY LIGHT AMOUNTS OF
SNOW ARE EXPECTED.

&&

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 418 AM EST TUE DEC 16 2014

ONLY MINOR VARIANCES WARRANTED FROM PRIOR FORECAST AND CORROBORATING
LATEST MODEL BLEND. CONTINUE UNIMPRESSED WRT LES RESPONSE MIDWEEK
GIVEN NOMINAL SATURATION DEPTH. 295 DEGREE CBL FLOW VEERS TO ABOUT
310 THROUGH WED/WED NIGHT...THOUGH LWR TEENS DIFFERENTIALS
GENERATING LTE 200 J/KG LAKE INDUCED CAPE WITH LK INDUCED EQL ONLY
TOPPING 4KFT WED AFTN/EVE. THEREAFTER...925-8H COLD POOL SHIFTS WELL
EWD THROUGH LWR GRTLKS/WRN PA BY DAYBREAK...PUTTING FINAL KIBOSH ON
ALREADY LACKLUSTER CONDITIONING. ADVANCE OF UPSTREAM NRN PLAINS/SRN
CANADA RIDGING POSES DIFFICULTY WRT CLOUD COVER AS DIRTY
RIDGE/TRAPPING SUBSIDENCE INVERSION AGAIN APPEARS PSBL THU/FRI.
MODELS TRENDS WRT EVOLUTION OF COMPLEX MULTI-EMBEDDED SHORTWAVE WEST
COAST TROF HAS BEEN DECIDEDLY SOUTHWARD SHUNT WRT SFC CYCLOGENESIS
FRI/SAT. COLLABORATIVELY REMOVED HIGH BIAS BLENDED POPS FRI
NIGHT...AND ONLY TOKEN LIGHT SNOW CHCS SAT...PERHAPS WITHIN LAGGED
INVERTED TROF WITHIN NRN DUMBBELL OF HEIGHT FALL CENTROID TRACKING
THROUGH SRN GRTLKS. NEXT SYSTEM TO WATCH APPEARS TO BE NRN STREAM
CLIPPER FOR POTNL LIGHT ACCUM ABOUT DY8.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 556 AM EST TUE DEC 16 2014

THE CORE OF THE UPPER LOW WAS OVER NORTHEAST IL AND WILL TRACK
EAST ACROSS SOUTHERN LOWER MICHIGAN TODAY. AN AREA OF RAIN
ASSOCIATED WITH AN UPPER LEVEL SHORT WAVE WAS ACCOMPANIED BY LOW
CIGS AND VSBYS. THIS SYSTEM WILL KEEP LOW CLOUDS AND VSBYS OVER
THE TERMINALS EARLY IN THE TAF PERIOD. EXPECT LOW TO VERY LOW IFR
CONDITIONS EARLY THIS MORNING AS THE UPPER LEVEL SYSTEM MOVES OVER
THE AREA. SOME IMPROVEMENT IS LIKELY AS THE LOW MOVES EAST AND AS
DRIER AIR SPREADS ACROSS THE AREA NEAR THE END OF THE TAF PERIOD.
WINDS WILL INCREASE AS THE GRADIENT TIGHTENS.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 5 AM EST
     THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...MARSILI/SKIPPER
SHORT TERM...SKIPPER
LONG TERM...MURPHY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA







000
FXUS63 KIWX 160923
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
423 AM EST TUE DEC 16 2014

.SYNOPSIS...
ISSUED AT 125 AM EST TUE DEC 15 2014

AN UPPER LEVEL DISTURBANCE AND LOW PRESSURE AREA WILL MOVE ACROSS
THE REGION ACCOMPANIED BY PERIODS OF RAIN THROUGH THIS MORNING.
LINGERING RAIN SHOWERS WILL PERSIST INTO THIS AFTERNOON. THE
PRECIPITATION WILL MIX WITH SNOW AND THEN CHANGE TO ALL SNOW
TONIGHT. SOME LIGHT SNOW ACCUMULATIONS ARE POSSIBLE TONIGHT...
ESPECIALLY OVER NORTHWEST INDIANA AND FAR SOUTHWEST LOWER
MICHIGAN. COLDER WEATHER WILL BE IN STORE FOR MID WEEK BEHIND
THIS SYSTEM. HIGHS TODAY SHOULD REACH THE MID AND UPPER 40S. LOWS
TONIGHT WILL BE MAINLY IN THE 20S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 418 AM EST TUE DEC 16 2014

AN UPPER LOW WAS OVER NORTHERN IL AND WILL TRACK EAST ACROSS FAR
NORTHERN INDIANA AND SOUTHERN LOWER MICHIGAN LATER TODAY. AN AREA
OF RAIN ASSOCIATED WITH A SHORT WAVE WILL MOVE ACROSS THE FORECAST
AREA EARLY TODAY. RADAR AND SURFACE REPORTS INDICATED ISOLATED
SLEET WAS MIXED IN WITH THE RAIN. ANY SLEET WILL BE BRIEF AND SHOULD
BE LOCAL AND SHOULD HAVE MINIMAL IMPACTS WITH SURFACE TEMPERATURES
AROUND 45 DEGREES. THE MAIN AREA OF LIFT WITH THE UPPER LOW IN
THE TROWAL WILL TRANSLATE NORTHEAST OUT OF THE AREA...ALLOWING
PRECIPITATION AMOUNTS TO BECOME LIGHT THIS AFTERNOON. THE REMAINING
PRECIPITATION WILL MIX WITH AND CHANGE TO SNOW TONIGHT AS COLDER
AIR SPREADS BACK OVER THE AREA...ALTHOUGH ONLY LIGHT AMOUNTS OF
SNOW ARE EXPECTED.

&&

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 418 AM EST TUE DEC 16 2014

ONLY MINOR VARIANCES WARRANTED FROM PRIOR FORECAST AND CORROBORATING
LATEST MODEL BLEND. CONTINUE UNIMPRESSED WRT LES RESPONSE MIDWEEK
GIVEN NOMINAL SATURATION DEPTH. 295 DEGREE CBL FLOW VEERS TO ABOUT
310 THROUGH WED/WED NIGHT...THOUGH LWR TEENS DIFFERENTIALS
GENERATING LTE 200 J/KG LAKE INDUCED CAPE WITH LK INDUCED EQL ONLY
TOPPING 4KFT WED AFTN/EVE. THEREAFTER...925-8H COLD POOL SHIFTS WELL
EWD THROUGH LWR GRTLKS/WRN PA BY DAYBREAK...PUTTING FINAL KIBOSH ON
ALREADY LACKLUSTER CONDITIONING. ADVANCE OF UPSTREAM NRN PLAINS/SRN
CANADA RIDGING POSES DIFFICULTY WRT CLOUD COVER AS DIRTY
RIDGE/TRAPPING SUBSIDENCE INVERSION AGAIN APPEARS PSBL THU/FRI.
MODELS TRENDS WRT EVOLUTION OF COMPLEX MULTI-EMBEDDED SHORTWAVE WEST
COAST TROF HAS BEEN DECIDEDLY SOUTHWARD SHUNT WRT SFC CYCLOGENESIS
FRI/SAT. COLLABORATIVELY REMOVED HIGH BIAS BLENDED POPS FRI
NIGHT...AND ONLY TOKEN LIGHT SNOW CHCS SAT...PERHAPS WITHIN LAGGED
INVERTED TROF WITHIN NRN DUMBBELL OF HEIGHT FALL CENTROID TRACKING
THROUGH SRN GRTLKS. NEXT SYSTEM TO WATCH APPEARS TO BE NRN STREAM
CLIPPER FOR POTNL LIGHT ACCUM ABOUT DY8.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 121 AM EST TUE DEC 16 2014

THE CORE OF THE UPPER LOW WAS OVER NW IL AND WILL TRACK EAST
ACROSS SOUTHERN LOWER MICHIGAN LATER TODAY. ANOTHER AREA OF RAIN
ASSOCIATED WITH AN UPPER LEVEL SHORT WAVE AND ACCOMPANIED BY LOW
CIGS AND VSBYS WILL SPREAD OVER THE TERMINALS EARLY IN THE TAF
PERIOD. EXPECT LOW TO VERY LOW IFR CONDITIONS EARLY THIS MORNING
AS THE UPPER LEVEL SYSTEM MOVES OVER THE AREA. SOME IMPROVEMENT IS
LIKELY AS THE LOW MOVES EAST FOLLOWED BY DRIER AIR SPREADING
ACROSS THE AREA NEAR THE END OF THE TAF PERIOD. HOWEVER...CIGS
MAY STILL BE IFR AT THE END OF THE TAF PERIOD.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 5 AM EST
     THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...MARSILI/SKIPPER
SHORT TERM...SKIPPER
LONG TERM...MURPHY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA







000
FXUS63 KIWX 160923
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
423 AM EST TUE DEC 16 2014

.SYNOPSIS...
ISSUED AT 125 AM EST TUE DEC 15 2014

AN UPPER LEVEL DISTURBANCE AND LOW PRESSURE AREA WILL MOVE ACROSS
THE REGION ACCOMPANIED BY PERIODS OF RAIN THROUGH THIS MORNING.
LINGERING RAIN SHOWERS WILL PERSIST INTO THIS AFTERNOON. THE
PRECIPITATION WILL MIX WITH SNOW AND THEN CHANGE TO ALL SNOW
TONIGHT. SOME LIGHT SNOW ACCUMULATIONS ARE POSSIBLE TONIGHT...
ESPECIALLY OVER NORTHWEST INDIANA AND FAR SOUTHWEST LOWER
MICHIGAN. COLDER WEATHER WILL BE IN STORE FOR MID WEEK BEHIND
THIS SYSTEM. HIGHS TODAY SHOULD REACH THE MID AND UPPER 40S. LOWS
TONIGHT WILL BE MAINLY IN THE 20S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 418 AM EST TUE DEC 16 2014

AN UPPER LOW WAS OVER NORTHERN IL AND WILL TRACK EAST ACROSS FAR
NORTHERN INDIANA AND SOUTHERN LOWER MICHIGAN LATER TODAY. AN AREA
OF RAIN ASSOCIATED WITH A SHORT WAVE WILL MOVE ACROSS THE FORECAST
AREA EARLY TODAY. RADAR AND SURFACE REPORTS INDICATED ISOLATED
SLEET WAS MIXED IN WITH THE RAIN. ANY SLEET WILL BE BRIEF AND SHOULD
BE LOCAL AND SHOULD HAVE MINIMAL IMPACTS WITH SURFACE TEMPERATURES
AROUND 45 DEGREES. THE MAIN AREA OF LIFT WITH THE UPPER LOW IN
THE TROWAL WILL TRANSLATE NORTHEAST OUT OF THE AREA...ALLOWING
PRECIPITATION AMOUNTS TO BECOME LIGHT THIS AFTERNOON. THE REMAINING
PRECIPITATION WILL MIX WITH AND CHANGE TO SNOW TONIGHT AS COLDER
AIR SPREADS BACK OVER THE AREA...ALTHOUGH ONLY LIGHT AMOUNTS OF
SNOW ARE EXPECTED.

&&

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 418 AM EST TUE DEC 16 2014

ONLY MINOR VARIANCES WARRANTED FROM PRIOR FORECAST AND CORROBORATING
LATEST MODEL BLEND. CONTINUE UNIMPRESSED WRT LES RESPONSE MIDWEEK
GIVEN NOMINAL SATURATION DEPTH. 295 DEGREE CBL FLOW VEERS TO ABOUT
310 THROUGH WED/WED NIGHT...THOUGH LWR TEENS DIFFERENTIALS
GENERATING LTE 200 J/KG LAKE INDUCED CAPE WITH LK INDUCED EQL ONLY
TOPPING 4KFT WED AFTN/EVE. THEREAFTER...925-8H COLD POOL SHIFTS WELL
EWD THROUGH LWR GRTLKS/WRN PA BY DAYBREAK...PUTTING FINAL KIBOSH ON
ALREADY LACKLUSTER CONDITIONING. ADVANCE OF UPSTREAM NRN PLAINS/SRN
CANADA RIDGING POSES DIFFICULTY WRT CLOUD COVER AS DIRTY
RIDGE/TRAPPING SUBSIDENCE INVERSION AGAIN APPEARS PSBL THU/FRI.
MODELS TRENDS WRT EVOLUTION OF COMPLEX MULTI-EMBEDDED SHORTWAVE WEST
COAST TROF HAS BEEN DECIDEDLY SOUTHWARD SHUNT WRT SFC CYCLOGENESIS
FRI/SAT. COLLABORATIVELY REMOVED HIGH BIAS BLENDED POPS FRI
NIGHT...AND ONLY TOKEN LIGHT SNOW CHCS SAT...PERHAPS WITHIN LAGGED
INVERTED TROF WITHIN NRN DUMBBELL OF HEIGHT FALL CENTROID TRACKING
THROUGH SRN GRTLKS. NEXT SYSTEM TO WATCH APPEARS TO BE NRN STREAM
CLIPPER FOR POTNL LIGHT ACCUM ABOUT DY8.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 121 AM EST TUE DEC 16 2014

THE CORE OF THE UPPER LOW WAS OVER NW IL AND WILL TRACK EAST
ACROSS SOUTHERN LOWER MICHIGAN LATER TODAY. ANOTHER AREA OF RAIN
ASSOCIATED WITH AN UPPER LEVEL SHORT WAVE AND ACCOMPANIED BY LOW
CIGS AND VSBYS WILL SPREAD OVER THE TERMINALS EARLY IN THE TAF
PERIOD. EXPECT LOW TO VERY LOW IFR CONDITIONS EARLY THIS MORNING
AS THE UPPER LEVEL SYSTEM MOVES OVER THE AREA. SOME IMPROVEMENT IS
LIKELY AS THE LOW MOVES EAST FOLLOWED BY DRIER AIR SPREADING
ACROSS THE AREA NEAR THE END OF THE TAF PERIOD. HOWEVER...CIGS
MAY STILL BE IFR AT THE END OF THE TAF PERIOD.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 5 AM EST
     THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...MARSILI/SKIPPER
SHORT TERM...SKIPPER
LONG TERM...MURPHY
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA








000
FXUS63 KIWX 160641
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
141 AM EST TUE DEC 16 2014

.SYNOPSIS...
ISSUED AT 125 AM EST TUE DEC 15 2014

AN UPPER LEVEL DISTURBANCE AND LOW PRESSURE AREA WILL MOVE ACROSS
THE REGION ACCOMPANIED BY PERIODS OF RAIN THROUGH THIS MORNING.
SCATTERED RAIN SHOWERS WILL PERSIST INTO THIS AFTERNOON...WITH
LINGERING PRECIPITATION MIXING WITH SNOW AND THEN CHANGING TO ALL
SNOW TONIGHT. SOME LIGHT SNOW ACCUMULATIONS ARE POSSIBLE TONIGHT.
COLDER WEATHER WILL BE IN STORE FOR MID WEEK BEHIND THIS SYSTEM.
TEMPERATURES THROUGH EARLY THIS MORNING WILL REMAIN STEADY IN THE
LOW TO MID 40S. HIGHS TODAY SHOULD REACH THE MID AND UPPER 40S.

&&

.UPDATE...
ISSUED AT 730 PM EST MON DEC 15 2014

NEAR TERM UPDATES THIS EVENING HAVE BEEN MAINLY TO FOCUS ON POP
EVOLUTION. THE COMBINATION OF LEAD VORT MAX EJECTING AHEAD OF
PARENT UPPER CIRCULATION ACROSS SOUTHERN IOWA AND NARROW CORRIDOR
OF ENHANCED LOW LEVEL MOISTURE CONVERGENCE HAS LED TO BAND OF RAIN
PROGRESSING ACROSS THE AREA. MAIN TWEAKS TO POPS WERE FOCUSED ON
RESOLVING PROGRESSION OF THIS BAND OVER THE NEXT FEW HOURS ACROSS
EASTERN PORTIONS OF THE FORECAST AREA. DID LOWER POPS TO CHANCE
CATEGORY FOR A TIME LATER THIS EVENING INTO THE EARLY PORTION OF
THE OVERNIGHT HOURS BEFORE ANOTHER VORT MAX ASSOCIATED WITH UPPER
SPEED MAX NOSING INTO THE MID MS VALLEY BEGINS TO WRAP
CYCLONICALLY INTO THE OHIO RIVER VALLEY/SOUTHERN GREAT LAKES
REGION. LOW LEVEL MOISTURE AXIS ALSO SHOULD REMAIN ANCHORED ACROSS
THE REGION INTO TUESDAY MORNING...AND HAVE NOT MADE SIGNIFICANT
CHANGES TO LIKELY/CATEGORICAL POPS AFTER 09Z. OTHERWISE...PREVIOUS
GRIDS REMAIN ON TRACK...AND MAY JUST MAKE SLIGHT DOWNWARD
ADJUSTMENT TO MINS BASED ON CURRENT OBSERVATIONAL TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 315 PM EST MON DEC 15 2014

BLOCKY PATTN ALOFT IN CONCERT W/HEADACHE INDUCING DIRTY RIDGE
FINALLY ON THE WAY OUT THIS PD AS POTENT CYCLONE OVR NW MO EJECTS
OUT ACRS THE SRN LAKES. BAND OF -RA ALG LEADING EDGE OF UPR
TROUGH/VERTICAL ASCENT PLUME HAD DECAYED OUT EWD W/TIME INTO WRN IN
AS FOCUS REDVLPD BACK WWD N-S THROUGH ERN IL. XPCD THIS BAND TO
DOMINATE GOING INTO THIS EVENING W/A GENERAL NEWD EXPANSION FVRD AS
NOTED IN ALL HIGHRES GUIDANCE. OTRWS HEAVIER RAIN POTENTIAL STILL
INDICATED FOR LT TONIGHT AS IMPRESSIVE MID LVL DRY SLOT WRAPS
OVERHEAD. SOME THUNDER NOTED EARLIER OVR NE KS/SE NE HWVR CIRC
INDICATED TO OPEN UP TUE AM W/WKNG WCB AND SUBDUED NWD THETA-E WRAP.
REGARDLESS DECENT AREA OF RAINFALL SHLD MATERIALIZE OVR NRN/ERN
AREAS TWD DAYBREAK.

ON TUE...OPENING CIRC ALOFT WILL PASS OVERHEAD MIDDAY AS MOIST
CYCLONIC FLW ENVELOPES CWA AND XPC OCCASIONAL SHRA TO PERSIST. HWVR
FOCUS FOR GREATER IMPLIED COVERAGE/INTENSITIES SHLD REMAIN GENERALLY
REMAIN ALG/NORTH OF HIGHWAY 6 IN PROXIMITY TO DECAYING MID LVL
DEFORMATION ZONE. TEMPS THROUGH THE PD LTL CHGD UNTIL CAA WING WRAPS
UNDERNEATH DEPARTING CYCLONE TUE NIGHT.

&&

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 315 PM EST MON DEC 15 2014

...LIGHT LAKE EFFECT SNOW SHOWERS EXPECTED WEDNESDAY AND
THURSDAY...THEN DEVELOPING LOW PRESSURE MAY BRING LIGHT SNOW FOR THE
WEEKEND....

A VERTICALLY STACKED LOW PRESSURE SYSTEM CENTERED OVER LAKE HURON
WILL GRADUALLY SHIFT EASTWARD INTO SOUTHERN ONTARIO TUESDAY NIGHT.
MEANWHILE...SFC HIGH PRESSURE WILL GRADUALLY DRIFT INTO THE WESTERN
GREAT LAKES THROUGH FRIDAY WITH ANOTHER SHORTWAVE/UPPER LEVEL LOW
LINGERING ALOFT. IN THE WAKE OF THE LOW...CAA ON WEST-NORTHWEST
WINDS WILL INTRODUCE THE POSSIBILITY OF LAKE EFFECT SNOW/RAIN
SHOWERS IN WNW WIND FAVORED AREAS...MAINLY FAR SW LOWER MI/NW
INDIANA. NOT EXPECTING ANYTHING SIGNIFICANT HOWEVER...AS MOISTURE
AND INSTABILITY ARE LACKING. WITH LAKE TEMPS AROUND 4-5C...700MB
DELTA TS STRUGGLE TO REACH 15C BY 12Z WEDNESDAY...AND THETA E LAPSE
RATES ARE FAIRLY PALTRY. SUBSIDENCE FROM THE INCOMING HIGH PRESSURE
WILL ALSO LIMIT CONVECTIVE DEPTH...WITH THE SUBSEQUENT INVERSION
DROPPING TO AROUND 875MB BY WEDNESDAY AM. THE INCOMING DRIER AIRMASS
WILL ALSO LEAVE US WITH A RATHER UNHEALTHY DGZ...WITH RH LESS THAN
20 PERCENT WITHIN THE -12 TO -18C LAYER. EARLY IN THE
EVENING...EXPECT A BIT OF MIXED PRECIPITATION...AS SFC TEMPS ARE
ABOVE FREEZING. AS DRYING TREND INCREASES ALOFT...WE COULD EVEN SEE
A BRIEF PERIOD OF FREEZING DRIZZLE. BY 6Z HOWEVER...ALL
PRECIPITATION SHOULD TRANSITION TO SNOW AS SFC TEMPS DROP BELOW
FREEZING. KEPT MARGINAL POPS IN WNW WIND FAVORED AREAS...GENERALLY
FLURRIES TO LIGHT SNOW SHOWERS.

THOUGH HIGH PRESSURE IS INCOMING...EXPECT PARTLY TO MOSTLY CLOUDY
SKIES TO LINGER WEDNESDAY AS MOISTURE IS ONCE AGAIN TRAPPED BENEATH
THE SUBSIDENCE INVERSION. LIGHT SNOW SHOWERS IN THE NORTHWEST ARE
EXPECTED TO CONTINUE THROUGHOUT THE DAY. CYCLONIC FLOW ALOFT WILL
ALSO BRING A FEW WEAK SHORTWAVES ACROSS THE CWA...WHICH WILL SERVE
TO LIFT INVERSION HEIGHTS TO NEAR 800 MB AT TIMES. HIGH TEMPERATURES
RETURN TO NEAR NORMAL FOR DECEMBER...PRIMARILY IN THE 30S.

SNOW SHOWERS WILL PERSIST NEAR LAKE MI INTO THURSDAY AFTERNOON WITH
THE 500MB FLOW BECOMING RELATIVELY ZONAL...BUT AS THE UPPER LEVEL
RIDGE BEGINS TO BUILD IN OVERHEAD...TEMPERATURES ALOFT BEGIN TO
WARM. ENDED ALL POPS BY 00Z FRIDAY AS A RESULT.

SFC LOW PRESSURE DEVELOPING IN THE GULF STATES WITH A DEEP UPPER
LEVEL TROUGH CENTERED OVER THE PLAINS WILL BEGIN TO LIFT
NORTHEASTWARD SATURDAY. BOTH THE ECMWF/GFS BRING THE CENTER OF THE
LOW INTO VIRGINIA/WEST VIRGINIA BY 00Z SUNDAY...HOWEVER THEY DIFFER
WITH RESPECT TO THE UPPER LEVEL TROUGH DEVELOPING INTO A CLOSED LOW.
THIS SYSTEM WILL BRING CHANCES FOR SNOW OVER THE WEEKEND. GFS IS
MORE PROGRESSIVE AND BRINGS THE PRECIPITATION INTO OUR CWA BY
SATURDAY 12Z...BUT THE ECMWF LINGERS BACK BY ABOUT 6-12 HOURS. KEPT
CONSENSUS POPS FOR NOW. TEMPERATURES WILL BE SOMETHING TO WATCH...AS
WE COULD SEE A RAIN/SNOW MIX DURING THIS PERIOD. WITH THE LATEST
MODEL TRENDS KEEPING US IN THE COLDER AIR BEHIND THE SYSTEM...KEPT
TEMPS RIGHT AROUND FREEZING FOR NOW...AND KEPT SNOW AS THE P-TYPE.
MONDAY WILL BE RELATIVELY QUIET AS HIGH PRESSURE RETURNS TO THE AREA.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 121 AM EST TUE DEC 16 2014

THE CORE OF THE UPPER LOW WAS OVER NW IL AND WILL TRACK EAST
ACROSS SOUTHERN LOWER MICHIGAN LATER TODAY. ANOTHER AREA OF RAIN
ASSOCIATED WITH AN UPPER LEVEL SHORT WAVE AND ACCOMPANIED BY LOW
CIGS AND VSBYS WILL SPREAD OVER THE TERMINALS EARLY IN THE TAF
PERIOD. EXPECT LOW TO VERY LOW IFR CONDITIONS EARLY THIS MORNING
AS THE UPPER LEVEL SYSTEM MOVES OVER THE AREA. SOME IMPROVEMENT IS
LIKELY AS THE LOW MOVES EAST FOLLOWED BY DRIER AIR SPREADING
ACROSS THE AREA NEAR THE END OF THE TAF PERIOD. HOWEVER...CIGS
MAY STILL BE IFR AT THE END OF THE TAF PERIOD.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 5 AM EST
     THURSDAY FOR LMZ043-046.

&&

$$

UPDATE...MARSILI
SYNOPSIS...MARSILI/SKIPPER
SHORT TERM...T
LONG TERM...MCD
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA







000
FXUS63 KIWX 160641
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
141 AM EST TUE DEC 16 2014

.SYNOPSIS...
ISSUED AT 125 AM EST TUE DEC 15 2014

AN UPPER LEVEL DISTURBANCE AND LOW PRESSURE AREA WILL MOVE ACROSS
THE REGION ACCOMPANIED BY PERIODS OF RAIN THROUGH THIS MORNING.
SCATTERED RAIN SHOWERS WILL PERSIST INTO THIS AFTERNOON...WITH
LINGERING PRECIPITATION MIXING WITH SNOW AND THEN CHANGING TO ALL
SNOW TONIGHT. SOME LIGHT SNOW ACCUMULATIONS ARE POSSIBLE TONIGHT.
COLDER WEATHER WILL BE IN STORE FOR MID WEEK BEHIND THIS SYSTEM.
TEMPERATURES THROUGH EARLY THIS MORNING WILL REMAIN STEADY IN THE
LOW TO MID 40S. HIGHS TODAY SHOULD REACH THE MID AND UPPER 40S.

&&

.UPDATE...
ISSUED AT 730 PM EST MON DEC 15 2014

NEAR TERM UPDATES THIS EVENING HAVE BEEN MAINLY TO FOCUS ON POP
EVOLUTION. THE COMBINATION OF LEAD VORT MAX EJECTING AHEAD OF
PARENT UPPER CIRCULATION ACROSS SOUTHERN IOWA AND NARROW CORRIDOR
OF ENHANCED LOW LEVEL MOISTURE CONVERGENCE HAS LED TO BAND OF RAIN
PROGRESSING ACROSS THE AREA. MAIN TWEAKS TO POPS WERE FOCUSED ON
RESOLVING PROGRESSION OF THIS BAND OVER THE NEXT FEW HOURS ACROSS
EASTERN PORTIONS OF THE FORECAST AREA. DID LOWER POPS TO CHANCE
CATEGORY FOR A TIME LATER THIS EVENING INTO THE EARLY PORTION OF
THE OVERNIGHT HOURS BEFORE ANOTHER VORT MAX ASSOCIATED WITH UPPER
SPEED MAX NOSING INTO THE MID MS VALLEY BEGINS TO WRAP
CYCLONICALLY INTO THE OHIO RIVER VALLEY/SOUTHERN GREAT LAKES
REGION. LOW LEVEL MOISTURE AXIS ALSO SHOULD REMAIN ANCHORED ACROSS
THE REGION INTO TUESDAY MORNING...AND HAVE NOT MADE SIGNIFICANT
CHANGES TO LIKELY/CATEGORICAL POPS AFTER 09Z. OTHERWISE...PREVIOUS
GRIDS REMAIN ON TRACK...AND MAY JUST MAKE SLIGHT DOWNWARD
ADJUSTMENT TO MINS BASED ON CURRENT OBSERVATIONAL TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 315 PM EST MON DEC 15 2014

BLOCKY PATTN ALOFT IN CONCERT W/HEADACHE INDUCING DIRTY RIDGE
FINALLY ON THE WAY OUT THIS PD AS POTENT CYCLONE OVR NW MO EJECTS
OUT ACRS THE SRN LAKES. BAND OF -RA ALG LEADING EDGE OF UPR
TROUGH/VERTICAL ASCENT PLUME HAD DECAYED OUT EWD W/TIME INTO WRN IN
AS FOCUS REDVLPD BACK WWD N-S THROUGH ERN IL. XPCD THIS BAND TO
DOMINATE GOING INTO THIS EVENING W/A GENERAL NEWD EXPANSION FVRD AS
NOTED IN ALL HIGHRES GUIDANCE. OTRWS HEAVIER RAIN POTENTIAL STILL
INDICATED FOR LT TONIGHT AS IMPRESSIVE MID LVL DRY SLOT WRAPS
OVERHEAD. SOME THUNDER NOTED EARLIER OVR NE KS/SE NE HWVR CIRC
INDICATED TO OPEN UP TUE AM W/WKNG WCB AND SUBDUED NWD THETA-E WRAP.
REGARDLESS DECENT AREA OF RAINFALL SHLD MATERIALIZE OVR NRN/ERN
AREAS TWD DAYBREAK.

ON TUE...OPENING CIRC ALOFT WILL PASS OVERHEAD MIDDAY AS MOIST
CYCLONIC FLW ENVELOPES CWA AND XPC OCCASIONAL SHRA TO PERSIST. HWVR
FOCUS FOR GREATER IMPLIED COVERAGE/INTENSITIES SHLD REMAIN GENERALLY
REMAIN ALG/NORTH OF HIGHWAY 6 IN PROXIMITY TO DECAYING MID LVL
DEFORMATION ZONE. TEMPS THROUGH THE PD LTL CHGD UNTIL CAA WING WRAPS
UNDERNEATH DEPARTING CYCLONE TUE NIGHT.

&&

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 315 PM EST MON DEC 15 2014

...LIGHT LAKE EFFECT SNOW SHOWERS EXPECTED WEDNESDAY AND
THURSDAY...THEN DEVELOPING LOW PRESSURE MAY BRING LIGHT SNOW FOR THE
WEEKEND....

A VERTICALLY STACKED LOW PRESSURE SYSTEM CENTERED OVER LAKE HURON
WILL GRADUALLY SHIFT EASTWARD INTO SOUTHERN ONTARIO TUESDAY NIGHT.
MEANWHILE...SFC HIGH PRESSURE WILL GRADUALLY DRIFT INTO THE WESTERN
GREAT LAKES THROUGH FRIDAY WITH ANOTHER SHORTWAVE/UPPER LEVEL LOW
LINGERING ALOFT. IN THE WAKE OF THE LOW...CAA ON WEST-NORTHWEST
WINDS WILL INTRODUCE THE POSSIBILITY OF LAKE EFFECT SNOW/RAIN
SHOWERS IN WNW WIND FAVORED AREAS...MAINLY FAR SW LOWER MI/NW
INDIANA. NOT EXPECTING ANYTHING SIGNIFICANT HOWEVER...AS MOISTURE
AND INSTABILITY ARE LACKING. WITH LAKE TEMPS AROUND 4-5C...700MB
DELTA TS STRUGGLE TO REACH 15C BY 12Z WEDNESDAY...AND THETA E LAPSE
RATES ARE FAIRLY PALTRY. SUBSIDENCE FROM THE INCOMING HIGH PRESSURE
WILL ALSO LIMIT CONVECTIVE DEPTH...WITH THE SUBSEQUENT INVERSION
DROPPING TO AROUND 875MB BY WEDNESDAY AM. THE INCOMING DRIER AIRMASS
WILL ALSO LEAVE US WITH A RATHER UNHEALTHY DGZ...WITH RH LESS THAN
20 PERCENT WITHIN THE -12 TO -18C LAYER. EARLY IN THE
EVENING...EXPECT A BIT OF MIXED PRECIPITATION...AS SFC TEMPS ARE
ABOVE FREEZING. AS DRYING TREND INCREASES ALOFT...WE COULD EVEN SEE
A BRIEF PERIOD OF FREEZING DRIZZLE. BY 6Z HOWEVER...ALL
PRECIPITATION SHOULD TRANSITION TO SNOW AS SFC TEMPS DROP BELOW
FREEZING. KEPT MARGINAL POPS IN WNW WIND FAVORED AREAS...GENERALLY
FLURRIES TO LIGHT SNOW SHOWERS.

THOUGH HIGH PRESSURE IS INCOMING...EXPECT PARTLY TO MOSTLY CLOUDY
SKIES TO LINGER WEDNESDAY AS MOISTURE IS ONCE AGAIN TRAPPED BENEATH
THE SUBSIDENCE INVERSION. LIGHT SNOW SHOWERS IN THE NORTHWEST ARE
EXPECTED TO CONTINUE THROUGHOUT THE DAY. CYCLONIC FLOW ALOFT WILL
ALSO BRING A FEW WEAK SHORTWAVES ACROSS THE CWA...WHICH WILL SERVE
TO LIFT INVERSION HEIGHTS TO NEAR 800 MB AT TIMES. HIGH TEMPERATURES
RETURN TO NEAR NORMAL FOR DECEMBER...PRIMARILY IN THE 30S.

SNOW SHOWERS WILL PERSIST NEAR LAKE MI INTO THURSDAY AFTERNOON WITH
THE 500MB FLOW BECOMING RELATIVELY ZONAL...BUT AS THE UPPER LEVEL
RIDGE BEGINS TO BUILD IN OVERHEAD...TEMPERATURES ALOFT BEGIN TO
WARM. ENDED ALL POPS BY 00Z FRIDAY AS A RESULT.

SFC LOW PRESSURE DEVELOPING IN THE GULF STATES WITH A DEEP UPPER
LEVEL TROUGH CENTERED OVER THE PLAINS WILL BEGIN TO LIFT
NORTHEASTWARD SATURDAY. BOTH THE ECMWF/GFS BRING THE CENTER OF THE
LOW INTO VIRGINIA/WEST VIRGINIA BY 00Z SUNDAY...HOWEVER THEY DIFFER
WITH RESPECT TO THE UPPER LEVEL TROUGH DEVELOPING INTO A CLOSED LOW.
THIS SYSTEM WILL BRING CHANCES FOR SNOW OVER THE WEEKEND. GFS IS
MORE PROGRESSIVE AND BRINGS THE PRECIPITATION INTO OUR CWA BY
SATURDAY 12Z...BUT THE ECMWF LINGERS BACK BY ABOUT 6-12 HOURS. KEPT
CONSENSUS POPS FOR NOW. TEMPERATURES WILL BE SOMETHING TO WATCH...AS
WE COULD SEE A RAIN/SNOW MIX DURING THIS PERIOD. WITH THE LATEST
MODEL TRENDS KEEPING US IN THE COLDER AIR BEHIND THE SYSTEM...KEPT
TEMPS RIGHT AROUND FREEZING FOR NOW...AND KEPT SNOW AS THE P-TYPE.
MONDAY WILL BE RELATIVELY QUIET AS HIGH PRESSURE RETURNS TO THE AREA.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 121 AM EST TUE DEC 16 2014

THE CORE OF THE UPPER LOW WAS OVER NW IL AND WILL TRACK EAST
ACROSS SOUTHERN LOWER MICHIGAN LATER TODAY. ANOTHER AREA OF RAIN
ASSOCIATED WITH AN UPPER LEVEL SHORT WAVE AND ACCOMPANIED BY LOW
CIGS AND VSBYS WILL SPREAD OVER THE TERMINALS EARLY IN THE TAF
PERIOD. EXPECT LOW TO VERY LOW IFR CONDITIONS EARLY THIS MORNING
AS THE UPPER LEVEL SYSTEM MOVES OVER THE AREA. SOME IMPROVEMENT IS
LIKELY AS THE LOW MOVES EAST FOLLOWED BY DRIER AIR SPREADING
ACROSS THE AREA NEAR THE END OF THE TAF PERIOD. HOWEVER...CIGS
MAY STILL BE IFR AT THE END OF THE TAF PERIOD.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 5 AM EST
     THURSDAY FOR LMZ043-046.

&&

$$

UPDATE...MARSILI
SYNOPSIS...MARSILI/SKIPPER
SHORT TERM...T
LONG TERM...MCD
AVIATION...SKIPPER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA








000
FXUS63 KIWX 160056
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
756 PM EST MON DEC 15 2014

.SYNOPSIS...
ISSUED AT 730 PM EST MON DEC 15 2014

AN UPPER LEVEL DISTURBANCE AND LOW PRESSURE AREA WILL MOVE ACROSS
THE REGION BRINGING A LIKELIHOOD OF RAIN TONIGHT INTO TUESDAY
MORNING. SCATTERED RAIN SHOWERS WILL PERSIST INTO TUESDAY
AFTERNOON...WITH A FEW SNOW SHOWERS POSSIBLY MIXING IN TUESDAY
NIGHT. COOLER WEATHER WILL BE IN STORE FOR MID WEEK BEHIND THIS
SYSTEM. LOW TEMPERATURES TONIGHT WILL DROP INTO THE LOWER
40S...WITH HIGH TEMPERATURES ON TUESDAY MAINLY INTO THE MID AND
UPPER 40S.

&&

.UPDATE...
ISSUED AT 730 PM EST MON DEC 15 2014

NEAR TERM UPDATES THIS EVENING HAVE BEEN MAINLY TO FOCUS ON POP
EVOLUTION. THE COMBINATION OF LEAD VORT MAX EJECTING AHEAD OF
PARENT UPPER CIRCULATION ACROSS SOUTHERN IOWA AND NARROW CORRIDOR
OF ENHANCED LOW LEVEL MOISTURE CONVERGENCE HAS LED TO BAND OF RAIN
PROGRESSING ACROSS THE AREA. MAIN TWEAKS TO POPS WERE FOCUSED ON
RESOLVING PROGRESSION OF THIS BAND OVER THE NEXT FEW HOURS ACROSS
EASTERN PORTIONS OF THE FORECAST AREA. DID LOWER POPS TO CHANCE
CATEGORY FOR A TIME LATER THIS EVENING INTO THE EARLY PORTION OF
THE OVERNIGHT HOURS BEFORE ANOTHER VORT MAX ASSOCIATED WITH UPPER
SPEED MAX NOSING INTO THE MID MS VALLEY BEGINS TO WRAP
CYCLONICALLY INTO THE OHIO RIVER VALLEY/SOUTHERN GREAT LAKES
REGION. LOW LEVEL MOISTURE AXIS ALSO SHOULD REMAIN ANCHORED ACROSS
THE REGION INTO TUESDAY MORNING...AND HAVE NOT MADE SIGNIFICANT
CHANGES TO LIKELY/CATEGORICAL POPS AFTER 09Z. OTHERWISE...PREVIOUS
GRIDS REMAIN ON TRACK...AND MAY JUST MAKE SLIGHT DOWNWARD
ADJUSTMENT TO MINS BASED ON CURRENT OBSERVATIONAL TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 315 PM EST MON DEC 15 2014

BLOCKY PATTN ALOFT IN CONCERT W/HEADACHE INDUCING DIRTY RIDGE
FINALLY ON THE WAY OUT THIS PD AS POTENT CYCLONE OVR NW MO EJECTS
OUT ACRS THE SRN LAKES. BAND OF -RA ALG LEADING EDGE OF UPR
TROUGH/VERTICAL ASCENT PLUME HAD DECAYED OUT EWD W/TIME INTO WRN IN
AS FOCUS REDVLPD BACK WWD N-S THROUGH ERN IL. XPCD THIS BAND TO
DOMINATE GOING INTO THIS EVENING W/A GENERAL NEWD EXPANSION FVRD AS
NOTED IN ALL HIGHRES GUIDANCE. OTRWS HEAVIER RAIN POTENTIAL STILL
INDICATED FOR LT TONIGHT AS IMPRESSIVE MID LVL DRY SLOT WRAPS
OVERHEAD. SOME THUNDER NOTED EARLIER OVR NE KS/SE NE HWVR CIRC
INDICATED TO OPEN UP TUE AM W/WKNG WCB AND SUBDUED NWD THETA-E WRAP.
REGARDLESS DECENT AREA OF RAINFALL SHLD MATERIALIZE OVR NRN/ERN
AREAS TWD DAYBREAK.

ON TUE...OPENING CIRC ALOFT WILL PASS OVERHEAD MIDDAY AS MOIST
CYCLONIC FLW ENVELOPES CWA AND XPC OCCASIONAL SHRA TO PERSIST. HWVR
FOCUS FOR GREATER IMPLIED COVERAGE/INTENSITIES SHLD REMAIN GENERALLY
REMAIN ALG/NORTH OF HIGHWAY 6 IN PROXIMITY TO DECAYING MID LVL
DEFORMATION ZONE. TEMPS THROUGH THE PD LTL CHGD UNTIL CAA WING WRAPS
UNDERNEATH DEPARTING CYCLONE TUE NIGHT.

&&

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 315 PM EST MON DEC 15 2014

...LIGHT LAKE EFFECT SNOW SHOWERS EXPECTED WEDNESDAY AND
THURSDAY...THEN DEVELOPING LOW PRESSURE MAY BRING LIGHT SNOW FOR THE
WEEKEND....

A VERTICALLY STACKED LOW PRESSURE SYSTEM CENTERED OVER LAKE HURON
WILL GRADUALLY SHIFT EASTWARD INTO SOUTHERN ONTARIO TUESDAY NIGHT.
MEANWHILE...SFC HIGH PRESSURE WILL GRADUALLY DRIFT INTO THE WESTERN
GREAT LAKES THROUGH FRIDAY WITH ANOTHER SHORTWAVE/UPPER LEVEL LOW
LINGERING ALOFT. IN THE WAKE OF THE LOW...CAA ON WEST-NORTHWEST
WINDS WILL INTRODUCE THE POSSIBILITY OF LAKE EFFECT SNOW/RAIN
SHOWERS IN WNW WIND FAVORED AREAS...MAINLY FAR SW LOWER MI/NW
INDIANA. NOT EXPECTING ANYTHING SIGNIFICANT HOWEVER...AS MOISTURE
AND INSTABILITY ARE LACKING. WITH LAKE TEMPS AROUND 4-5C...700MB
DELTA TS STRUGGLE TO REACH 15C BY 12Z WEDNESDAY...AND THETA E LAPSE
RATES ARE FAIRLY PALTRY. SUBSIDENCE FROM THE INCOMING HIGH PRESSURE
WILL ALSO LIMIT CONVECTIVE DEPTH...WITH THE SUBSEQUENT INVERSION
DROPPING TO AROUND 875MB BY WEDNESDAY AM. THE INCOMING DRIER AIRMASS
WILL ALSO LEAVE US WITH A RATHER UNHEALTHY DGZ...WITH RH LESS THAN
20 PERCENT WITHIN THE -12 TO -18C LAYER. EARLY IN THE
EVENING...EXPECT A BIT OF MIXED PRECIPITATION...AS SFC TEMPS ARE
ABOVE FREEZING. AS DRYING TREND INCREASES ALOFT...WE COULD EVEN SEE
A BRIEF PERIOD OF FREEZING DRIZZLE. BY 6Z HOWEVER...ALL
PRECIPITATION SHOULD TRANSITION TO SNOW AS SFC TEMPS DROP BELOW
FREEZING. KEPT MARGINAL POPS IN WNW WIND FAVORED AREAS...GENERALLY
FLURRIES TO LIGHT SNOW SHOWERS.

THOUGH HIGH PRESSURE IS INCOMING...EXPECT PARTLY TO MOSTLY CLOUDY
SKIES TO LINGER WEDNESDAY AS MOISTURE IS ONCE AGAIN TRAPPED BENEATH
THE SUBSIDENCE INVERSION. LIGHT SNOW SHOWERS IN THE NORTHWEST ARE
EXPECTED TO CONTINUE THROUGHOUT THE DAY. CYCLONIC FLOW ALOFT WILL
ALSO BRING A FEW WEAK SHORTWAVES ACROSS THE CWA...WHICH WILL SERVE
TO LIFT INVERSION HEIGHTS TO NEAR 800 MB AT TIMES. HIGH TEMPERATURES
RETURN TO NEAR NORMAL FOR DECEMBER...PRIMARILY IN THE 30S.

SNOW SHOWERS WILL PERSIST NEAR LAKE MI INTO THURSDAY AFTERNOON WITH
THE 500MB FLOW BECOMING RELATIVELY ZONAL...BUT AS THE UPPER LEVEL
RIDGE BEGINS TO BUILD IN OVERHEAD...TEMPERATURES ALOFT BEGIN TO
WARM. ENDED ALL POPS BY 00Z FRIDAY AS A RESULT.

SFC LOW PRESSURE DEVELOPING IN THE GULF STATES WITH A DEEP UPPER
LEVEL TROUGH CENTERED OVER THE PLAINS WILL BEGIN TO LIFT
NORTHEASTWARD SATURDAY. BOTH THE ECMWF/GFS BRING THE CENTER OF THE
LOW INTO VIRGINIA/WEST VIRGINIA BY 00Z SUNDAY...HOWEVER THEY DIFFER
WITH RESPECT TO THE UPPER LEVEL TROUGH DEVELOPING INTO A CLOSED LOW.
THIS SYSTEM WILL BRING CHANCES FOR SNOW OVER THE WEEKEND. GFS IS
MORE PROGRESSIVE AND BRINGS THE PRECIPITATION INTO OUR CWA BY
SATURDAY 12Z...BUT THE ECMWF LINGERS BACK BY ABOUT 6-12 HOURS. KEPT
CONSENSUS POPS FOR NOW. TEMPERATURES WILL BE SOMETHING TO WATCH...AS
WE COULD SEE A RAIN/SNOW MIX DURING THIS PERIOD. WITH THE LATEST
MODEL TRENDS KEEPING US IN THE COLDER AIR BEHIND THE SYSTEM...KEPT
TEMPS RIGHT AROUND FREEZING FOR NOW...AND KEPT SNOW AS THE P-TYPE.
MONDAY WILL BE RELATIVELY QUIET AS HIGH PRESSURE RETURNS TO THE AREA.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 730 PM EST MON DEC 15 2014

STRONG LOW LEVEL MOISTURE GRADIENT WILL CONTINUE TO LIFT NORTHWARD
ACROSS NORTHERN INDIANA AS SOUTHERLY FLOW HAS RAMPED UP IN ADVANCE
OF UPPER TROUGH ACROSS THE MID MS RIVER VALLEY. AFTER A PERIOD OF
RAIN AT TERMINALS THIS EVENING...A BREAK IN PRECIP IS EXPECTED
LATE THIS EVENING INTO THE POSSIBLY THE EARLY PORTIONS OF THE
OVERNIGHT HOURS BEFORE SCATTERED TO NUMEROUS SHOWERS REDEVELOP.
CIGS SHOULD DETERIORATE TO IFR THIS EVENING...AND POSSIBLY TO LIFR
AT KSBN LATE EVENING OR OVERNIGHT. IFR CONDITIONS ARE EXPECTED TO
PERSIST INTO TUESDAY MORNING...WITH BETTER CHANCE OF IMPROVEMENT
TO MVFR LATE IN THE PERIOD TUESDAY AFTERNOON. TRACK OF ASSOCIATED
LOW PRESSURE AREA WILL ALLOW FOR SOUTHEAST WINDS TONIGHT TO VEER
SOUTHWEST TUESDAY AFTERNOON WITH GUSTS TO 20 KNOTS POSSIBLE.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 3 PM TUESDAY TO 5 AM EST THURSDAY FOR
     LMZ043-046.

&&

$$

UPDATE...MARSILI
SYNOPSIS...MARSILI
SHORT TERM...T
LONG TERM...MCD
AVIATION...MARSILI


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA








000
FXUS63 KIWX 160056
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
756 PM EST MON DEC 15 2014

.SYNOPSIS...
ISSUED AT 730 PM EST MON DEC 15 2014

AN UPPER LEVEL DISTURBANCE AND LOW PRESSURE AREA WILL MOVE ACROSS
THE REGION BRINGING A LIKELIHOOD OF RAIN TONIGHT INTO TUESDAY
MORNING. SCATTERED RAIN SHOWERS WILL PERSIST INTO TUESDAY
AFTERNOON...WITH A FEW SNOW SHOWERS POSSIBLY MIXING IN TUESDAY
NIGHT. COOLER WEATHER WILL BE IN STORE FOR MID WEEK BEHIND THIS
SYSTEM. LOW TEMPERATURES TONIGHT WILL DROP INTO THE LOWER
40S...WITH HIGH TEMPERATURES ON TUESDAY MAINLY INTO THE MID AND
UPPER 40S.

&&

.UPDATE...
ISSUED AT 730 PM EST MON DEC 15 2014

NEAR TERM UPDATES THIS EVENING HAVE BEEN MAINLY TO FOCUS ON POP
EVOLUTION. THE COMBINATION OF LEAD VORT MAX EJECTING AHEAD OF
PARENT UPPER CIRCULATION ACROSS SOUTHERN IOWA AND NARROW CORRIDOR
OF ENHANCED LOW LEVEL MOISTURE CONVERGENCE HAS LED TO BAND OF RAIN
PROGRESSING ACROSS THE AREA. MAIN TWEAKS TO POPS WERE FOCUSED ON
RESOLVING PROGRESSION OF THIS BAND OVER THE NEXT FEW HOURS ACROSS
EASTERN PORTIONS OF THE FORECAST AREA. DID LOWER POPS TO CHANCE
CATEGORY FOR A TIME LATER THIS EVENING INTO THE EARLY PORTION OF
THE OVERNIGHT HOURS BEFORE ANOTHER VORT MAX ASSOCIATED WITH UPPER
SPEED MAX NOSING INTO THE MID MS VALLEY BEGINS TO WRAP
CYCLONICALLY INTO THE OHIO RIVER VALLEY/SOUTHERN GREAT LAKES
REGION. LOW LEVEL MOISTURE AXIS ALSO SHOULD REMAIN ANCHORED ACROSS
THE REGION INTO TUESDAY MORNING...AND HAVE NOT MADE SIGNIFICANT
CHANGES TO LIKELY/CATEGORICAL POPS AFTER 09Z. OTHERWISE...PREVIOUS
GRIDS REMAIN ON TRACK...AND MAY JUST MAKE SLIGHT DOWNWARD
ADJUSTMENT TO MINS BASED ON CURRENT OBSERVATIONAL TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 315 PM EST MON DEC 15 2014

BLOCKY PATTN ALOFT IN CONCERT W/HEADACHE INDUCING DIRTY RIDGE
FINALLY ON THE WAY OUT THIS PD AS POTENT CYCLONE OVR NW MO EJECTS
OUT ACRS THE SRN LAKES. BAND OF -RA ALG LEADING EDGE OF UPR
TROUGH/VERTICAL ASCENT PLUME HAD DECAYED OUT EWD W/TIME INTO WRN IN
AS FOCUS REDVLPD BACK WWD N-S THROUGH ERN IL. XPCD THIS BAND TO
DOMINATE GOING INTO THIS EVENING W/A GENERAL NEWD EXPANSION FVRD AS
NOTED IN ALL HIGHRES GUIDANCE. OTRWS HEAVIER RAIN POTENTIAL STILL
INDICATED FOR LT TONIGHT AS IMPRESSIVE MID LVL DRY SLOT WRAPS
OVERHEAD. SOME THUNDER NOTED EARLIER OVR NE KS/SE NE HWVR CIRC
INDICATED TO OPEN UP TUE AM W/WKNG WCB AND SUBDUED NWD THETA-E WRAP.
REGARDLESS DECENT AREA OF RAINFALL SHLD MATERIALIZE OVR NRN/ERN
AREAS TWD DAYBREAK.

ON TUE...OPENING CIRC ALOFT WILL PASS OVERHEAD MIDDAY AS MOIST
CYCLONIC FLW ENVELOPES CWA AND XPC OCCASIONAL SHRA TO PERSIST. HWVR
FOCUS FOR GREATER IMPLIED COVERAGE/INTENSITIES SHLD REMAIN GENERALLY
REMAIN ALG/NORTH OF HIGHWAY 6 IN PROXIMITY TO DECAYING MID LVL
DEFORMATION ZONE. TEMPS THROUGH THE PD LTL CHGD UNTIL CAA WING WRAPS
UNDERNEATH DEPARTING CYCLONE TUE NIGHT.

&&

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 315 PM EST MON DEC 15 2014

...LIGHT LAKE EFFECT SNOW SHOWERS EXPECTED WEDNESDAY AND
THURSDAY...THEN DEVELOPING LOW PRESSURE MAY BRING LIGHT SNOW FOR THE
WEEKEND....

A VERTICALLY STACKED LOW PRESSURE SYSTEM CENTERED OVER LAKE HURON
WILL GRADUALLY SHIFT EASTWARD INTO SOUTHERN ONTARIO TUESDAY NIGHT.
MEANWHILE...SFC HIGH PRESSURE WILL GRADUALLY DRIFT INTO THE WESTERN
GREAT LAKES THROUGH FRIDAY WITH ANOTHER SHORTWAVE/UPPER LEVEL LOW
LINGERING ALOFT. IN THE WAKE OF THE LOW...CAA ON WEST-NORTHWEST
WINDS WILL INTRODUCE THE POSSIBILITY OF LAKE EFFECT SNOW/RAIN
SHOWERS IN WNW WIND FAVORED AREAS...MAINLY FAR SW LOWER MI/NW
INDIANA. NOT EXPECTING ANYTHING SIGNIFICANT HOWEVER...AS MOISTURE
AND INSTABILITY ARE LACKING. WITH LAKE TEMPS AROUND 4-5C...700MB
DELTA TS STRUGGLE TO REACH 15C BY 12Z WEDNESDAY...AND THETA E LAPSE
RATES ARE FAIRLY PALTRY. SUBSIDENCE FROM THE INCOMING HIGH PRESSURE
WILL ALSO LIMIT CONVECTIVE DEPTH...WITH THE SUBSEQUENT INVERSION
DROPPING TO AROUND 875MB BY WEDNESDAY AM. THE INCOMING DRIER AIRMASS
WILL ALSO LEAVE US WITH A RATHER UNHEALTHY DGZ...WITH RH LESS THAN
20 PERCENT WITHIN THE -12 TO -18C LAYER. EARLY IN THE
EVENING...EXPECT A BIT OF MIXED PRECIPITATION...AS SFC TEMPS ARE
ABOVE FREEZING. AS DRYING TREND INCREASES ALOFT...WE COULD EVEN SEE
A BRIEF PERIOD OF FREEZING DRIZZLE. BY 6Z HOWEVER...ALL
PRECIPITATION SHOULD TRANSITION TO SNOW AS SFC TEMPS DROP BELOW
FREEZING. KEPT MARGINAL POPS IN WNW WIND FAVORED AREAS...GENERALLY
FLURRIES TO LIGHT SNOW SHOWERS.

THOUGH HIGH PRESSURE IS INCOMING...EXPECT PARTLY TO MOSTLY CLOUDY
SKIES TO LINGER WEDNESDAY AS MOISTURE IS ONCE AGAIN TRAPPED BENEATH
THE SUBSIDENCE INVERSION. LIGHT SNOW SHOWERS IN THE NORTHWEST ARE
EXPECTED TO CONTINUE THROUGHOUT THE DAY. CYCLONIC FLOW ALOFT WILL
ALSO BRING A FEW WEAK SHORTWAVES ACROSS THE CWA...WHICH WILL SERVE
TO LIFT INVERSION HEIGHTS TO NEAR 800 MB AT TIMES. HIGH TEMPERATURES
RETURN TO NEAR NORMAL FOR DECEMBER...PRIMARILY IN THE 30S.

SNOW SHOWERS WILL PERSIST NEAR LAKE MI INTO THURSDAY AFTERNOON WITH
THE 500MB FLOW BECOMING RELATIVELY ZONAL...BUT AS THE UPPER LEVEL
RIDGE BEGINS TO BUILD IN OVERHEAD...TEMPERATURES ALOFT BEGIN TO
WARM. ENDED ALL POPS BY 00Z FRIDAY AS A RESULT.

SFC LOW PRESSURE DEVELOPING IN THE GULF STATES WITH A DEEP UPPER
LEVEL TROUGH CENTERED OVER THE PLAINS WILL BEGIN TO LIFT
NORTHEASTWARD SATURDAY. BOTH THE ECMWF/GFS BRING THE CENTER OF THE
LOW INTO VIRGINIA/WEST VIRGINIA BY 00Z SUNDAY...HOWEVER THEY DIFFER
WITH RESPECT TO THE UPPER LEVEL TROUGH DEVELOPING INTO A CLOSED LOW.
THIS SYSTEM WILL BRING CHANCES FOR SNOW OVER THE WEEKEND. GFS IS
MORE PROGRESSIVE AND BRINGS THE PRECIPITATION INTO OUR CWA BY
SATURDAY 12Z...BUT THE ECMWF LINGERS BACK BY ABOUT 6-12 HOURS. KEPT
CONSENSUS POPS FOR NOW. TEMPERATURES WILL BE SOMETHING TO WATCH...AS
WE COULD SEE A RAIN/SNOW MIX DURING THIS PERIOD. WITH THE LATEST
MODEL TRENDS KEEPING US IN THE COLDER AIR BEHIND THE SYSTEM...KEPT
TEMPS RIGHT AROUND FREEZING FOR NOW...AND KEPT SNOW AS THE P-TYPE.
MONDAY WILL BE RELATIVELY QUIET AS HIGH PRESSURE RETURNS TO THE AREA.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 730 PM EST MON DEC 15 2014

STRONG LOW LEVEL MOISTURE GRADIENT WILL CONTINUE TO LIFT NORTHWARD
ACROSS NORTHERN INDIANA AS SOUTHERLY FLOW HAS RAMPED UP IN ADVANCE
OF UPPER TROUGH ACROSS THE MID MS RIVER VALLEY. AFTER A PERIOD OF
RAIN AT TERMINALS THIS EVENING...A BREAK IN PRECIP IS EXPECTED
LATE THIS EVENING INTO THE POSSIBLY THE EARLY PORTIONS OF THE
OVERNIGHT HOURS BEFORE SCATTERED TO NUMEROUS SHOWERS REDEVELOP.
CIGS SHOULD DETERIORATE TO IFR THIS EVENING...AND POSSIBLY TO LIFR
AT KSBN LATE EVENING OR OVERNIGHT. IFR CONDITIONS ARE EXPECTED TO
PERSIST INTO TUESDAY MORNING...WITH BETTER CHANCE OF IMPROVEMENT
TO MVFR LATE IN THE PERIOD TUESDAY AFTERNOON. TRACK OF ASSOCIATED
LOW PRESSURE AREA WILL ALLOW FOR SOUTHEAST WINDS TONIGHT TO VEER
SOUTHWEST TUESDAY AFTERNOON WITH GUSTS TO 20 KNOTS POSSIBLE.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 3 PM TUESDAY TO 5 AM EST THURSDAY FOR
     LMZ043-046.

&&

$$

UPDATE...MARSILI
SYNOPSIS...MARSILI
SHORT TERM...T
LONG TERM...MCD
AVIATION...MARSILI


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