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000
FXUS63 KIWX 302118 CCA
AFDIWX

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE NORTHERN INDIANA
417 PM EST FRI JAN 30 2015

.SYNOPSIS...
ISSUED AT 405 PM EST FRI JAN 30 2015

LAKE EFFECT CLOUDS AND FLURRIES WILL CONTINUE TO DIMINISH THIS
EVENING AS HIGH PRESSURE BUILDS ACROSS THE REGION. LOW
TEMPERATURES TONIGHT WILL DROP BACK INTO THE TEENS. HIGHS ON
SATURDAY WILL BE IN THE 30S. A DEVELOPING WINTER STORM WILL
IMPACT THE REGION STARTING SATURDAY NIGHT AND CONTINUING INTO
SUNDAY. WINTER STORM WATCHES REMAIN IN EFFECT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 PM EST FRI JAN 30 2015

BENIGN WEATHER EXPECTED THROUGH SATURDAY AS HIGH PRESSURE DRIFTS
ACROSS THE REGION. BANDS OF LAKE EFFECT CLOUDS AND FLURRIES HAVE
BEEN STEADILY CONTRACTING PAST COUPLE OF HOURS WITH THIS TREND
LIKELY TO INCREASE AS WE CLOSE IN ON THE EARLY EVENING HOURS. THE
CLEAR SKIES AND DIMINISHING WINDS WILL ALLOW LOWS TO DROP INTO
THE TEENS AS THE HIGH DRIFTS OVERHEAD.

THE REGION WILL BE ON THE WARM SIDE OF THE HIGH ON SATURDAY
ALLOWING AFTERNOON HIGHS TO CLIMB TO NEAR OR ABOVE
FREEZING...ALLOWING FOR TEMPORARILY IMPROVING ROAD CONDITIONS
PRIOR TO THE ARRIVAL OF THE SNOW SATURDAY EVENING.

&&

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 405 PM EST FRI JAN 30 2015

12 UTC MODELS/COBB OUTPUT ALONG WITH 09/15 UTC SREF ENSEMBLE
PLUMES LENDING INCREASED CONFIDENCE FOR SIG EVENT SAT NIGHT
THROUGH SUN NIGHT...LEADING TO PRIOR MIDDAY ISSUANCE OF WINTER
STORM WATCH FOLLOWING WPC/INTEROFFICE COORD. SW/BAJA VORTEX
PUMPING EXTREME MOISTURE TRANSPORT NWD. 4-6 G/KG PLUS WITHIN
850-500 MB EXTRUDED NWD FM SWRN MEXICO INTO INTMTN/CENTRAL ROCKIES
TO HARMONIOUSLY MELD WITH HIGH MOISTURE LADEN WRN VANCOUVER WAVE
INTO SAT. PRESENCE OF HUDSON BAY AND SWRN VORTEX TO AID IN PHASING
TO SHARPLY HEWN SEWD DIVING SHORTWAVE THROUGH NRN PLAINS INTO MID
MS VLY. INCREASINGLY RAMPED HGHT FALLS WITH LONG DURATION TO AID
IN LARGE SCALE ASCENT. PROLONGED EWD REACH OF HGHT ADJUSTMENTS
NOTED AS HFC IN EXCESS OF 100M/12HR SUN AM INTENSIFIES UPWARDS OF
180M/12 HR AS IT INTO SWRN OH/NRN KY BY 12 UTC MON.
EXTREME/PROLONGED MFLUX CONVERGENCE IN E-W FASHION THROUGH NRN IL
INTO NWRN OH PER I285/I290K NAM ISENTROPIC SFCS. 50 KT SWRLY
JETLET ORTHOGONAL TO ISENT SFCS MOVES EWD FM SERN MO UP OHIO BASIN
SUN AM TO NEAR KCVG BY 00 UTC MON. 7H TRACK IN LARGELY
OPEN/POSITIVE TILT TO WEAKLY CLOSED ALONG ROUTE 6 CORRIDOR AND
HINT OF TROWAL AT I285K JUST SOUTH...ALONG WITH TIGHTER ENSEMBLE
SPREAD LENDS HIR CONFIDENCE TO FARTHER NWD SWATH OF HEAVIEST
SNOWFALL. WHILE CONFIDENCE OF SIG EVENT/6 PLUS INCHES IS VERY
HIGH...EVENTUAL PLACEMENT AND DETAILS ALONG N/S GRADIENT EDGES
STILL EVOKE HESITANCE/UNCERTAINTY. THEREFORE ENTIRE CWA UNDER WSW
FOR 6 TO 12 INCHES POSSIBLE...WITH LATER RUNS PROVIDING SUFFICIENT
CONFIDENCE FOR UPG WARNING/ADV DECISIONS...LIKELY EARLY AM SUN AND
CERTAINLY BY NOON SHOULD DEFERENCE BE MADE TO 12 UTC SUN MODEL
OUTPUT. WHAT COULD GO WRONG...INCLUSION OF PLATES/NEEDLES IN DEEP
SUPERSATURATION ABOVE THE DGZ COULD LEAD TO MORE GRANULAR FLAKES
AND ANY FARTHER NWD TREND WOULD BEGIN TO GREATLY LESSEN FAR SRN
CWA SLR AS COLUMN WARMS...THOUGH SRN CWA NAM BUFKIT SITES FIRM IN
FROZEN/SNOW PTYPE PER ENERGY NOMOGRAM. RAMPED GRADIENT FLOW TO
BRING PD OF BLSN ESP LATE SUN AFTN/EVE AS OH VLY SFC LOW DEEPENS
ALONG TRACK THROUGH MID INTO UPR OH VLY.

BRIEF LES IN WAKE OF SYSTEM...THOUGH INITIAL BAND MAY SET WEST OF
CWA UNTIL BACKING FLOW BY DAYBREAK MON. THEREAFTER DRY AIR
INTRUSION ALONG WITH LOWERING/STRENGTHENING SUBSIDENCE INVERSION
SHOULD GREATLY MITIGATE NWRN CWA ACCUMS. WEAK CLIPPER SYSTEM INTO
GRTLKS TUE NIGHT/WED...FOLLOWED AGAIN BY AT LEAST WEAK LES
RESPONSE AS PRIMARY TROF AXIS SHARPENS FM HUDSON BAY INTO LWR
GRTLKS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1245 PM EST FRI JAN 30 2015

MARGINAL MVFR CIGS WILL PERSIST AT KSBN THROUGH THE AFTERNOON WITH
EVENTUAL TREND TO CLEARING SKIES TONIGHT. RADAR RETURNS AND SFC
REPORTS SHOWING LITTLE MORE THAN FLURRIES HERE AND THERE SO NO
VSBY IMPACTS EXPECTED.

AFTER 00Z SAT LITTLE IN THE WAY OF SENSIBLE WEATHER CONCERNS AS
HIGH PRESSURE DOMINATES.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY EVENING
     FOR INZ003>009-012>018-020-022>027-032>034.

MI...WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY EVENING
     FOR MIZ077>081.

OH...WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY EVENING
     FOR OHZ001-002-004-005-015-016-024-025.

LM...NONE.
&&

$$

SYNOPSIS...MURPHY
SHORT TERM...FISHER
LONG TERM...MURPHY
AVIATION...FISHER


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 302118 CCA
AFDIWX

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE NORTHERN INDIANA
417 PM EST FRI JAN 30 2015

.SYNOPSIS...
ISSUED AT 405 PM EST FRI JAN 30 2015

LAKE EFFECT CLOUDS AND FLURRIES WILL CONTINUE TO DIMINISH THIS
EVENING AS HIGH PRESSURE BUILDS ACROSS THE REGION. LOW
TEMPERATURES TONIGHT WILL DROP BACK INTO THE TEENS. HIGHS ON
SATURDAY WILL BE IN THE 30S. A DEVELOPING WINTER STORM WILL
IMPACT THE REGION STARTING SATURDAY NIGHT AND CONTINUING INTO
SUNDAY. WINTER STORM WATCHES REMAIN IN EFFECT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 PM EST FRI JAN 30 2015

BENIGN WEATHER EXPECTED THROUGH SATURDAY AS HIGH PRESSURE DRIFTS
ACROSS THE REGION. BANDS OF LAKE EFFECT CLOUDS AND FLURRIES HAVE
BEEN STEADILY CONTRACTING PAST COUPLE OF HOURS WITH THIS TREND
LIKELY TO INCREASE AS WE CLOSE IN ON THE EARLY EVENING HOURS. THE
CLEAR SKIES AND DIMINISHING WINDS WILL ALLOW LOWS TO DROP INTO
THE TEENS AS THE HIGH DRIFTS OVERHEAD.

THE REGION WILL BE ON THE WARM SIDE OF THE HIGH ON SATURDAY
ALLOWING AFTERNOON HIGHS TO CLIMB TO NEAR OR ABOVE
FREEZING...ALLOWING FOR TEMPORARILY IMPROVING ROAD CONDITIONS
PRIOR TO THE ARRIVAL OF THE SNOW SATURDAY EVENING.

&&

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 405 PM EST FRI JAN 30 2015

12 UTC MODELS/COBB OUTPUT ALONG WITH 09/15 UTC SREF ENSEMBLE
PLUMES LENDING INCREASED CONFIDENCE FOR SIG EVENT SAT NIGHT
THROUGH SUN NIGHT...LEADING TO PRIOR MIDDAY ISSUANCE OF WINTER
STORM WATCH FOLLOWING WPC/INTEROFFICE COORD. SW/BAJA VORTEX
PUMPING EXTREME MOISTURE TRANSPORT NWD. 4-6 G/KG PLUS WITHIN
850-500 MB EXTRUDED NWD FM SWRN MEXICO INTO INTMTN/CENTRAL ROCKIES
TO HARMONIOUSLY MELD WITH HIGH MOISTURE LADEN WRN VANCOUVER WAVE
INTO SAT. PRESENCE OF HUDSON BAY AND SWRN VORTEX TO AID IN PHASING
TO SHARPLY HEWN SEWD DIVING SHORTWAVE THROUGH NRN PLAINS INTO MID
MS VLY. INCREASINGLY RAMPED HGHT FALLS WITH LONG DURATION TO AID
IN LARGE SCALE ASCENT. PROLONGED EWD REACH OF HGHT ADJUSTMENTS
NOTED AS HFC IN EXCESS OF 100M/12HR SUN AM INTENSIFIES UPWARDS OF
180M/12 HR AS IT INTO SWRN OH/NRN KY BY 12 UTC MON.
EXTREME/PROLONGED MFLUX CONVERGENCE IN E-W FASHION THROUGH NRN IL
INTO NWRN OH PER I285/I290K NAM ISENTROPIC SFCS. 50 KT SWRLY
JETLET ORTHOGONAL TO ISENT SFCS MOVES EWD FM SERN MO UP OHIO BASIN
SUN AM TO NEAR KCVG BY 00 UTC MON. 7H TRACK IN LARGELY
OPEN/POSITIVE TILT TO WEAKLY CLOSED ALONG ROUTE 6 CORRIDOR AND
HINT OF TROWAL AT I285K JUST SOUTH...ALONG WITH TIGHTER ENSEMBLE
SPREAD LENDS HIR CONFIDENCE TO FARTHER NWD SWATH OF HEAVIEST
SNOWFALL. WHILE CONFIDENCE OF SIG EVENT/6 PLUS INCHES IS VERY
HIGH...EVENTUAL PLACEMENT AND DETAILS ALONG N/S GRADIENT EDGES
STILL EVOKE HESITANCE/UNCERTAINTY. THEREFORE ENTIRE CWA UNDER WSW
FOR 6 TO 12 INCHES POSSIBLE...WITH LATER RUNS PROVIDING SUFFICIENT
CONFIDENCE FOR UPG WARNING/ADV DECISIONS...LIKELY EARLY AM SUN AND
CERTAINLY BY NOON SHOULD DEFERENCE BE MADE TO 12 UTC SUN MODEL
OUTPUT. WHAT COULD GO WRONG...INCLUSION OF PLATES/NEEDLES IN DEEP
SUPERSATURATION ABOVE THE DGZ COULD LEAD TO MORE GRANULAR FLAKES
AND ANY FARTHER NWD TREND WOULD BEGIN TO GREATLY LESSEN FAR SRN
CWA SLR AS COLUMN WARMS...THOUGH SRN CWA NAM BUFKIT SITES FIRM IN
FROZEN/SNOW PTYPE PER ENERGY NOMOGRAM. RAMPED GRADIENT FLOW TO
BRING PD OF BLSN ESP LATE SUN AFTN/EVE AS OH VLY SFC LOW DEEPENS
ALONG TRACK THROUGH MID INTO UPR OH VLY.

BRIEF LES IN WAKE OF SYSTEM...THOUGH INITIAL BAND MAY SET WEST OF
CWA UNTIL BACKING FLOW BY DAYBREAK MON. THEREAFTER DRY AIR
INTRUSION ALONG WITH LOWERING/STRENGTHENING SUBSIDENCE INVERSION
SHOULD GREATLY MITIGATE NWRN CWA ACCUMS. WEAK CLIPPER SYSTEM INTO
GRTLKS TUE NIGHT/WED...FOLLOWED AGAIN BY AT LEAST WEAK LES
RESPONSE AS PRIMARY TROF AXIS SHARPENS FM HUDSON BAY INTO LWR
GRTLKS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1245 PM EST FRI JAN 30 2015

MARGINAL MVFR CIGS WILL PERSIST AT KSBN THROUGH THE AFTERNOON WITH
EVENTUAL TREND TO CLEARING SKIES TONIGHT. RADAR RETURNS AND SFC
REPORTS SHOWING LITTLE MORE THAN FLURRIES HERE AND THERE SO NO
VSBY IMPACTS EXPECTED.

AFTER 00Z SAT LITTLE IN THE WAY OF SENSIBLE WEATHER CONCERNS AS
HIGH PRESSURE DOMINATES.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY EVENING
     FOR INZ003>009-012>018-020-022>027-032>034.

MI...WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY EVENING
     FOR MIZ077>081.

OH...WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY EVENING
     FOR OHZ001-002-004-005-015-016-024-025.

LM...NONE.
&&

$$

SYNOPSIS...MURPHY
SHORT TERM...FISHER
LONG TERM...MURPHY
AVIATION...FISHER


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 302108
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
408 PM EST FRI JAN 30 2015

.SYNOPSIS...
ISSUED AT 405 PM EST FRI JAN 30 2015

LAKE EFFECT CLOUDS AND FLURRIES WILL CONTINUE TO DIMINISH THIS
EVENING AS HIGH PRESSURE BUILDS ACROSS THE REGION. LOW
TEMPERATURES TONIGHT WILL DROP BACK INTO THE TEENS. HIGHS ON
SATURDAY WILL BE IN THE 30S. A DEVELOPING WINTER STORM WILL
IMPACT THE REGION STARTING SATURDAY NIGHT AND CONTINUING INTO
SUNDAY. WINTER STORM WATCHES REMAIN IN EFFECT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 PM EST FRI JAN 30 2015

BENIGN WEATHER EXPECTED THROUGH SATURDAY AS HIGH PRESSURE DRIFTS
ACROSS THE REGION. BANDS OF LAKE EFFECT CLOUDS AND FLURRIES HAVE
BEEN STEADILY CONTRACTING PAST COUPLE OF HOURS WITH THIS TREND
LIKELY TO INCREASE AS WE CLOSE IN ON THE EARLY EVENING HOURS. THE
CLEAR SKIES AND DIMINISHING WINDS WILL ALLOW LOWS TO DROP INTO
THE TEENS AS THE HIGH DRIFTS OVERHEAD.

THE REGION WILL BE ON THE WARM SIDE OF THE HIGH ON SATURDAY
ALLOWING AFTERNOON HIGHS TO CLIMB TO NEAR OR ABOVE
FREEZING...ALLOWING FOR TEMPORARILY IMPROVING ROAD CONDITIONS
PRIOR TO THE ARRIVAL OF THE SNOW SATURDAY EVENING.

&&

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 405 PM EST FRI JAN 30 2015

12 UTC MODELS/COBB OUTPUT ALONG WITH 09/15 UTC SREF ENSEMBLE
PLUMES LENDING INCREASED CONFIDENCE FOR SIG EVENT SAT NIGHT
THROUGH SUN NIGHT...LEADING TO PRIOR MIDDAY ISSUANCE OF WINTER
STORM WATCH FOLLOWING WPC/INTEROFFICE COORD. SW/BAJA VORTEX
PUMPING EXTREME MOISTURE TRANSPORT NWD. 4-6 G/KG PLUS WITHIN
850-500 MB EXTRUDED NWD FM SWRN MEXICO INTO INTMTN/CENTRAL ROCKIES
TO HARMONIOUSLY MELD WITH HIGH MOISTURE LADEN WRN VANCOUVER WAVE
INTO SAT. PRESENCE OF HUDSON BAY AND SWRN VORTEX TO AID IN PHASING
TO SHARPLY HEWN SEWD DIVING SHORTWAVE THROUGH NRN PLAINS INTO MID
MS VLY. INCREASINGLY RAMPED HGHT FALLS WITH LONG DURATION TO AID
IN LARGE SCALE ASCENT. PROLONGED EWD REACH OF HGHT ADJUSTMENTS
NOTED AS HFC IN EXCESS OF 100M/12HR SUN AM INTENSIFIES UPWARDS OF
180M/12 HR AS IT INTO SWRN OH/NRN KY BY 12 UTC MON.
EXTREME/PROLONGED MFLUX CONVERGENCE IN E-W FASHION THROUGH NRN IL
INTO NWRN OH PER I285/I290K NAM ISENTROPIC SFCS. 50 KT SWRLY
JETLET ORTHOGONAL TO ISENT SFCS MOVES EWD FM SERN MO UP OHIO BASIN
SUN AM TO NEAR KCVG BY 00 UTC MON. 7H TRACK IN LARGELY
OPEN/POSITIVE TILT TO WEAKLY CLOSED ALONG ROUTE 6 CORRIDOR AND
HINT OF TROWAL AT I285K JUST SOUTH...ALONG WITH TIGHTER ENSEMBLE
SPREAD LENDS HIR CONFIDENCE TO FARTHER NWD SWATH OF HEAVIEST
SNOWFALL. WHILE CONFIDENCE OF SIG EVENT/6 PLUS INCHES IS VERY
HIGH...EVENTUAL PLACEMENT AND DETAILS ALONG N/S GRADIENT EDGES
STILL EVOKE HESITANCE/UNCERTAINTY. THEREFORE ENTIRE CWA UNDER WSW
FOR 6 TO 12 INCHES POSSIBLE...WITH LATER RUNS PROVIDING SUFFICIENT
CONFIDENCE FOR UPG WARNING/ADV DECISIONS...LIKELY EARLY AM SUN AND
CERTAINLY BY NOON SHOULD DEFERENCE BE MADE TO 12 UTC SUN MODEL
OUTPUT. WHAT COULD GO WRONG...INCLUSION OF PLATES/NEEDLES IN DEEP
SUPERSATURATION ABOVE THE DGZ COULD LEAD TO MORE GRANULAR FLAKES
AND ANY FARTHER NWD TREND WOULD BEGIN TO GREATLY LESSEN FAR SRN
CWA SLR AS COLUMN WARMS...THOUGH SRN CWA NAM BUFKIT SITES FIRM IN
FROZEN/SNOW PTYPE PER ENERGY NOMOGRAM. RAMPED GRADIENT FLOW TO
BRING PD OF BLSN ESP LATE SUN AFTN/EVE AS OH VLY SFC LOW DEEPENS
ALONG TRACK THROUGH MID INTO UPR OH VLY.

BRIEF LES IN WAKE OF SYSTEM...THOUGH INITIAL BAND MAY SET WEST OF
CWA UNTIL BACKING FLOW BY DAYBREAK MON. THEREAFTER DRY AIR
INTRUSION ALONG WITH LOWERING/STRENGTHENING SUBSIDENCE INVERSION
SHOULD GREATLY MITIGATE NWRN CWA ACCUMS. WEAK CLIPPER SYSTEM INTO
GRTLKS TUE NIGHT/WED...FOLLOWED AGAIN BY AT LEAST WEAK LES
RESPONSE AS PRIMARY TROF AXIS SHARPENS FM HUDSON BAY INTO LWR
GRTLKS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1245 PM EST FRI JAN 30 2015

MARGINAL MVFR CIGS WILL PERSIST AT KSBN THROUGH THE AFTERNOON WITH
EVENTUAL TREND TO CLEARING SKIES TONIGHT. RADAR RETURNS AND SFC
REPORTS SHOWING LITTLE MORE THAN FLURRIES HERE AND THERE SO NO
VSBY IMPACTS EXPECTED.

AFTER 00Z SAT LITTLE IN THE WAY OF SENSIBLE WEATHER CONCERNS AS
HIGH PRESSURE DOMINATES.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY EVENING
     FOR INZ003>009-012>018-020-022>027-032>034.

MI...WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY EVENING
     FOR MIZ077>081.

OH...WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY EVENING
     FOR OHZ001-002-004-005-015-016-024-025.

LM...NONE.
&&

$$

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


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 302108
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
408 PM EST FRI JAN 30 2015

.SYNOPSIS...
ISSUED AT 405 PM EST FRI JAN 30 2015

LAKE EFFECT CLOUDS AND FLURRIES WILL CONTINUE TO DIMINISH THIS
EVENING AS HIGH PRESSURE BUILDS ACROSS THE REGION. LOW
TEMPERATURES TONIGHT WILL DROP BACK INTO THE TEENS. HIGHS ON
SATURDAY WILL BE IN THE 30S. A DEVELOPING WINTER STORM WILL
IMPACT THE REGION STARTING SATURDAY NIGHT AND CONTINUING INTO
SUNDAY. WINTER STORM WATCHES REMAIN IN EFFECT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 PM EST FRI JAN 30 2015

BENIGN WEATHER EXPECTED THROUGH SATURDAY AS HIGH PRESSURE DRIFTS
ACROSS THE REGION. BANDS OF LAKE EFFECT CLOUDS AND FLURRIES HAVE
BEEN STEADILY CONTRACTING PAST COUPLE OF HOURS WITH THIS TREND
LIKELY TO INCREASE AS WE CLOSE IN ON THE EARLY EVENING HOURS. THE
CLEAR SKIES AND DIMINISHING WINDS WILL ALLOW LOWS TO DROP INTO
THE TEENS AS THE HIGH DRIFTS OVERHEAD.

THE REGION WILL BE ON THE WARM SIDE OF THE HIGH ON SATURDAY
ALLOWING AFTERNOON HIGHS TO CLIMB TO NEAR OR ABOVE
FREEZING...ALLOWING FOR TEMPORARILY IMPROVING ROAD CONDITIONS
PRIOR TO THE ARRIVAL OF THE SNOW SATURDAY EVENING.

&&

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 405 PM EST FRI JAN 30 2015

12 UTC MODELS/COBB OUTPUT ALONG WITH 09/15 UTC SREF ENSEMBLE
PLUMES LENDING INCREASED CONFIDENCE FOR SIG EVENT SAT NIGHT
THROUGH SUN NIGHT...LEADING TO PRIOR MIDDAY ISSUANCE OF WINTER
STORM WATCH FOLLOWING WPC/INTEROFFICE COORD. SW/BAJA VORTEX
PUMPING EXTREME MOISTURE TRANSPORT NWD. 4-6 G/KG PLUS WITHIN
850-500 MB EXTRUDED NWD FM SWRN MEXICO INTO INTMTN/CENTRAL ROCKIES
TO HARMONIOUSLY MELD WITH HIGH MOISTURE LADEN WRN VANCOUVER WAVE
INTO SAT. PRESENCE OF HUDSON BAY AND SWRN VORTEX TO AID IN PHASING
TO SHARPLY HEWN SEWD DIVING SHORTWAVE THROUGH NRN PLAINS INTO MID
MS VLY. INCREASINGLY RAMPED HGHT FALLS WITH LONG DURATION TO AID
IN LARGE SCALE ASCENT. PROLONGED EWD REACH OF HGHT ADJUSTMENTS
NOTED AS HFC IN EXCESS OF 100M/12HR SUN AM INTENSIFIES UPWARDS OF
180M/12 HR AS IT INTO SWRN OH/NRN KY BY 12 UTC MON.
EXTREME/PROLONGED MFLUX CONVERGENCE IN E-W FASHION THROUGH NRN IL
INTO NWRN OH PER I285/I290K NAM ISENTROPIC SFCS. 50 KT SWRLY
JETLET ORTHOGONAL TO ISENT SFCS MOVES EWD FM SERN MO UP OHIO BASIN
SUN AM TO NEAR KCVG BY 00 UTC MON. 7H TRACK IN LARGELY
OPEN/POSITIVE TILT TO WEAKLY CLOSED ALONG ROUTE 6 CORRIDOR AND
HINT OF TROWAL AT I285K JUST SOUTH...ALONG WITH TIGHTER ENSEMBLE
SPREAD LENDS HIR CONFIDENCE TO FARTHER NWD SWATH OF HEAVIEST
SNOWFALL. WHILE CONFIDENCE OF SIG EVENT/6 PLUS INCHES IS VERY
HIGH...EVENTUAL PLACEMENT AND DETAILS ALONG N/S GRADIENT EDGES
STILL EVOKE HESITANCE/UNCERTAINTY. THEREFORE ENTIRE CWA UNDER WSW
FOR 6 TO 12 INCHES POSSIBLE...WITH LATER RUNS PROVIDING SUFFICIENT
CONFIDENCE FOR UPG WARNING/ADV DECISIONS...LIKELY EARLY AM SUN AND
CERTAINLY BY NOON SHOULD DEFERENCE BE MADE TO 12 UTC SUN MODEL
OUTPUT. WHAT COULD GO WRONG...INCLUSION OF PLATES/NEEDLES IN DEEP
SUPERSATURATION ABOVE THE DGZ COULD LEAD TO MORE GRANULAR FLAKES
AND ANY FARTHER NWD TREND WOULD BEGIN TO GREATLY LESSEN FAR SRN
CWA SLR AS COLUMN WARMS...THOUGH SRN CWA NAM BUFKIT SITES FIRM IN
FROZEN/SNOW PTYPE PER ENERGY NOMOGRAM. RAMPED GRADIENT FLOW TO
BRING PD OF BLSN ESP LATE SUN AFTN/EVE AS OH VLY SFC LOW DEEPENS
ALONG TRACK THROUGH MID INTO UPR OH VLY.

BRIEF LES IN WAKE OF SYSTEM...THOUGH INITIAL BAND MAY SET WEST OF
CWA UNTIL BACKING FLOW BY DAYBREAK MON. THEREAFTER DRY AIR
INTRUSION ALONG WITH LOWERING/STRENGTHENING SUBSIDENCE INVERSION
SHOULD GREATLY MITIGATE NWRN CWA ACCUMS. WEAK CLIPPER SYSTEM INTO
GRTLKS TUE NIGHT/WED...FOLLOWED AGAIN BY AT LEAST WEAK LES
RESPONSE AS PRIMARY TROF AXIS SHARPENS FM HUDSON BAY INTO LWR
GRTLKS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1245 PM EST FRI JAN 30 2015

MARGINAL MVFR CIGS WILL PERSIST AT KSBN THROUGH THE AFTERNOON WITH
EVENTUAL TREND TO CLEARING SKIES TONIGHT. RADAR RETURNS AND SFC
REPORTS SHOWING LITTLE MORE THAN FLURRIES HERE AND THERE SO NO
VSBY IMPACTS EXPECTED.

AFTER 00Z SAT LITTLE IN THE WAY OF SENSIBLE WEATHER CONCERNS AS
HIGH PRESSURE DOMINATES.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY EVENING
     FOR INZ003>009-012>018-020-022>027-032>034.

MI...WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY EVENING
     FOR MIZ077>081.

OH...WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY EVENING
     FOR OHZ001-002-004-005-015-016-024-025.

LM...NONE.
&&

$$

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


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 301750
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1250 PM EST FRI JAN 30 2015

.SYNOPSIS...
ISSUED AT 1245 PM EST FRI JAN 30 2015

LAKE EFFECT CLOUDS AND FLURRIES WILL CONTINUE TO DIMINISH THIS
AFTERNOON AS HIGH PRESSURE BUILDS ACROSS THE REGION. AFTERNOON
HIGHS WILL BE IN THE 20S WITH WARMEST READINGS UNDER ANY CLOUD
COVER. LOW TEMPERATURES TONIGHT WILL DROP BACK INTO THE TEENS. A
WINTER STORM WILL TAKE SHAPE AND IMPACT THE REGION STARTING
SATURDAY NIGHT. WINTER STORM WATCHES ARE IN EFFECT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 455 AM EST FRI JAN 30 2015

A VIGOROUS UPPER LEVEL TROUGH DROPPING ACROSS THE SOUTHERN GREAT
LAKES REGION PROVIDED SOME SYNOPTIC ENHANCEMENT TO PRECIP...BUT
STRONGER FORCING WITH THIS VORT MAX IS PROGRESSING EAST OF THE AREA
EARLY THIS MORNING. THIS WILL RESULT IN A CONTINUED TRANSITION TO
MORE OF PURE LAKE EFFECT SNOW SHOWER SCENARIO FOR THIS
MORNING...ALTHOUGH SETUP LOOKS TO BE ON THE MARGINAL SIDE.
REINFORCING LOW LEVEL CAA PUSH WITH SECONDARY SFC TROUGH PASSAGE
OVERNIGHT WILL KEEP SHALLOW BASED INSTABILITY IN PLACE FOR CONTINUED
LAKE EFFECT SNOW SHOWERS THIS MORNING...WITH INVERSION HEIGHTS
LOWERING THROUGH MID MORNING AS STRONGER SYNOPTIC SCALE SUBSIDENCE
IS ESTABLISHED IN THE WAKE OF DEPARTING UPPER LEVEL TROUGH. ANY
ACCUMULATIONS SHOULD GENERALLY BE LESS THAN AN INCH AND MAINLY
THROUGH MID TO LATE MORNING.

OTHERWISE FOR TODAY MAIN FORECAST CHALLENGE WILL BE RESOLVING SKY
COVER TRENDS. UPPER INFLECTION ZONE/LOW LEVEL ANTICYCLONE TO
OVERSPREAD THE REGION TODAY WITH EARLY MORNING GUSTY WINDS
DIMINISHING. MID LEVEL SYNOPTIC SUBSIDENCE TO CONTINUE THIS MORNING
AND ALREADY SEEING SOME DECENT EROSION OF LOW CLOUD DECK ACROSS
PORTIONS OF THE AREA. CONCERN IS THAT SHARPENING LOW LEVEL INVERSION
UNDER THE INFLUENCE OF THIS SUBSIDENCE MAY ALLOW STRATOCU TO PERSIST
THROUGH THE DAY...PARTICULARLY DOWNWIND OF LAKE MICHIGAN. RETREATING
LOW LEVEL THERMAL TROUGH WILL RESULT IN SOUTHWEST TO NORTHEAST
GRADIENT FOR MAX TEMPS TODAY RANGING FROM MID 20S SOUTHWEST TO
AROUND 20 FAR NORTHEAST. BACKING LOW LEVEL WINDS IN ASSOCIATION WITH
THE RIDGE OF HIGH PRESSURE SHOULD TAKE ANY RESIDUAL LAKE EFFECT
CLOUDINESS NORTHEASTWARD ACROSS FAR NORTHERN PORTIONS OF THE AREA
TONIGHT...WITH OVERALL TREND TO PARTLY CLOUDY/MOSTLY CLEAR SKIES AND
LIGHT WINDS ALLOWING FOR MINS TO DROP BACK INTO THE TEENS EARLY
SATURDAY MORNING.

&&

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 455 AM EST FRI JAN 30 2015

THE MAIN CHALLENGES THIS PERIOD INCLUDE THE TIMING AND TRACK OF A
SHORTWAVE TROF WELL UPSTREAM OVER ALASKA THAT WILL RACE SOUTHEAST
INTO THE WESTERN GREAT LAKES REGION. NCEP MODELS AND OTHERS HAVE
RECENTLY BEEN TRENDING NORTH WITH THIS SYSTEM. THE GARCIA/MIXING RAW
RATIO SNOWFALL FAVORS SNOWFALL AMOUNTS BETWEEN 8 AND 10 INCHES.
HOWEVER...ISSUES INCLUDING SATURATION TIME...LOW LEVEL DRY AIR
ENTRAINMENT AND CONVECTION ALONG AND SOUTH OF THE WARM FRONT MAY CUT
DEEPLY INTO SNOWFALL AMOUNTS. CURRENT THINKING IS EVENT SNOWFALL
TOTALS OF 4 TO 9 INCHES...WITH THE LOWER AMOUNTS NORTH OVER LOWER
MICHIGAN AND THE HIGHER AMOUNTS OVER NORTHERN INDIANA AND NORTHWEST
OHIO.  CIPS TOP 15 ANALOGS PAINT A SOLID 4 TO 6 INCHES OF SNOW
ACROSS THE AREA. AFTER COORDINATION WITH NEIGHBORING OFFICES...
HAVE ELECTED TO HOLD OFF ISSUING A WATCH DUE TO UNCERTAIN MODEL
HANDING OF THIS SYSTEM AMID LINGERING UNCERTAINTIES. WILL HIGHLIGHT
CONCERNS IN A SPECIAL WEATHER STATEMENT FOR NOW. OTHERWISE...MUCH
COLDER AIR WILL BE OVER THE AREA FOR THE UPCOMING WORK WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1245 PM EST FRI JAN 30 2015

MARGINAL MVFR CIGS WILL PERSIST AT KSBN THROUGH THE AFTERNOON WITH
EVENTUAL TREND TO CLEARING SKIES TONIGHT. RADAR RETURNS AND SFC
REPORTS SHOWING LITTLE MORE THAN FLURRIES HERE AND THERE SO NO
VSBY IMPACTS EXPECTED.

AFTER 00Z SAT LITTLE IN THE WAY OF SENSIBLE WEATHER CONCERNS AS
HIGH PRESSURE DOMINATES.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY EVENING
     FOR INZ003>009-012>018-020-022>027-032>034.

MI...WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY EVENING
     FOR MIZ077>081.

OH...WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY EVENING
     FOR OHZ001-002-004-005-015-016-024-025.

LM...NONE.
&&

$$

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


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 301750
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1250 PM EST FRI JAN 30 2015

.SYNOPSIS...
ISSUED AT 1245 PM EST FRI JAN 30 2015

LAKE EFFECT CLOUDS AND FLURRIES WILL CONTINUE TO DIMINISH THIS
AFTERNOON AS HIGH PRESSURE BUILDS ACROSS THE REGION. AFTERNOON
HIGHS WILL BE IN THE 20S WITH WARMEST READINGS UNDER ANY CLOUD
COVER. LOW TEMPERATURES TONIGHT WILL DROP BACK INTO THE TEENS. A
WINTER STORM WILL TAKE SHAPE AND IMPACT THE REGION STARTING
SATURDAY NIGHT. WINTER STORM WATCHES ARE IN EFFECT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 455 AM EST FRI JAN 30 2015

A VIGOROUS UPPER LEVEL TROUGH DROPPING ACROSS THE SOUTHERN GREAT
LAKES REGION PROVIDED SOME SYNOPTIC ENHANCEMENT TO PRECIP...BUT
STRONGER FORCING WITH THIS VORT MAX IS PROGRESSING EAST OF THE AREA
EARLY THIS MORNING. THIS WILL RESULT IN A CONTINUED TRANSITION TO
MORE OF PURE LAKE EFFECT SNOW SHOWER SCENARIO FOR THIS
MORNING...ALTHOUGH SETUP LOOKS TO BE ON THE MARGINAL SIDE.
REINFORCING LOW LEVEL CAA PUSH WITH SECONDARY SFC TROUGH PASSAGE
OVERNIGHT WILL KEEP SHALLOW BASED INSTABILITY IN PLACE FOR CONTINUED
LAKE EFFECT SNOW SHOWERS THIS MORNING...WITH INVERSION HEIGHTS
LOWERING THROUGH MID MORNING AS STRONGER SYNOPTIC SCALE SUBSIDENCE
IS ESTABLISHED IN THE WAKE OF DEPARTING UPPER LEVEL TROUGH. ANY
ACCUMULATIONS SHOULD GENERALLY BE LESS THAN AN INCH AND MAINLY
THROUGH MID TO LATE MORNING.

OTHERWISE FOR TODAY MAIN FORECAST CHALLENGE WILL BE RESOLVING SKY
COVER TRENDS. UPPER INFLECTION ZONE/LOW LEVEL ANTICYCLONE TO
OVERSPREAD THE REGION TODAY WITH EARLY MORNING GUSTY WINDS
DIMINISHING. MID LEVEL SYNOPTIC SUBSIDENCE TO CONTINUE THIS MORNING
AND ALREADY SEEING SOME DECENT EROSION OF LOW CLOUD DECK ACROSS
PORTIONS OF THE AREA. CONCERN IS THAT SHARPENING LOW LEVEL INVERSION
UNDER THE INFLUENCE OF THIS SUBSIDENCE MAY ALLOW STRATOCU TO PERSIST
THROUGH THE DAY...PARTICULARLY DOWNWIND OF LAKE MICHIGAN. RETREATING
LOW LEVEL THERMAL TROUGH WILL RESULT IN SOUTHWEST TO NORTHEAST
GRADIENT FOR MAX TEMPS TODAY RANGING FROM MID 20S SOUTHWEST TO
AROUND 20 FAR NORTHEAST. BACKING LOW LEVEL WINDS IN ASSOCIATION WITH
THE RIDGE OF HIGH PRESSURE SHOULD TAKE ANY RESIDUAL LAKE EFFECT
CLOUDINESS NORTHEASTWARD ACROSS FAR NORTHERN PORTIONS OF THE AREA
TONIGHT...WITH OVERALL TREND TO PARTLY CLOUDY/MOSTLY CLEAR SKIES AND
LIGHT WINDS ALLOWING FOR MINS TO DROP BACK INTO THE TEENS EARLY
SATURDAY MORNING.

&&

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 455 AM EST FRI JAN 30 2015

THE MAIN CHALLENGES THIS PERIOD INCLUDE THE TIMING AND TRACK OF A
SHORTWAVE TROF WELL UPSTREAM OVER ALASKA THAT WILL RACE SOUTHEAST
INTO THE WESTERN GREAT LAKES REGION. NCEP MODELS AND OTHERS HAVE
RECENTLY BEEN TRENDING NORTH WITH THIS SYSTEM. THE GARCIA/MIXING RAW
RATIO SNOWFALL FAVORS SNOWFALL AMOUNTS BETWEEN 8 AND 10 INCHES.
HOWEVER...ISSUES INCLUDING SATURATION TIME...LOW LEVEL DRY AIR
ENTRAINMENT AND CONVECTION ALONG AND SOUTH OF THE WARM FRONT MAY CUT
DEEPLY INTO SNOWFALL AMOUNTS. CURRENT THINKING IS EVENT SNOWFALL
TOTALS OF 4 TO 9 INCHES...WITH THE LOWER AMOUNTS NORTH OVER LOWER
MICHIGAN AND THE HIGHER AMOUNTS OVER NORTHERN INDIANA AND NORTHWEST
OHIO.  CIPS TOP 15 ANALOGS PAINT A SOLID 4 TO 6 INCHES OF SNOW
ACROSS THE AREA. AFTER COORDINATION WITH NEIGHBORING OFFICES...
HAVE ELECTED TO HOLD OFF ISSUING A WATCH DUE TO UNCERTAIN MODEL
HANDING OF THIS SYSTEM AMID LINGERING UNCERTAINTIES. WILL HIGHLIGHT
CONCERNS IN A SPECIAL WEATHER STATEMENT FOR NOW. OTHERWISE...MUCH
COLDER AIR WILL BE OVER THE AREA FOR THE UPCOMING WORK WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1245 PM EST FRI JAN 30 2015

MARGINAL MVFR CIGS WILL PERSIST AT KSBN THROUGH THE AFTERNOON WITH
EVENTUAL TREND TO CLEARING SKIES TONIGHT. RADAR RETURNS AND SFC
REPORTS SHOWING LITTLE MORE THAN FLURRIES HERE AND THERE SO NO
VSBY IMPACTS EXPECTED.

AFTER 00Z SAT LITTLE IN THE WAY OF SENSIBLE WEATHER CONCERNS AS
HIGH PRESSURE DOMINATES.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY EVENING
     FOR INZ003>009-012>018-020-022>027-032>034.

MI...WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY EVENING
     FOR MIZ077>081.

OH...WINTER STORM WATCH FROM SATURDAY EVENING THROUGH SUNDAY EVENING
     FOR OHZ001-002-004-005-015-016-024-025.

LM...NONE.
&&

$$

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


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 301146
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
646 AM EST FRI JAN 30 2015

.SYNOPSIS...
ISSUED AT 455 AM EST FRI JAN 30 2015

LAKE EFFECT SNOW SHOWERS WILL DIMINISH TODAY AS A RIDGE OF HIGH
PRESSURE BEGINS TO BUILD IN FROM THE WEST. THIS RIDGE OF HIGH
PRESSURE WILL DEPART TO THE EAST TONIGHT ALLOWING FOR A RETURN OF
SOUTHERLY WINDS AND MILDER CONDITIONS FOR SATURDAY. A STORM SYSTEM
WILL ORGANIZE ACROSS THE ROCKIES ON SATURDAY AND WILL BRING A GOOD
CHANCE OF ACCUMULATING SNOW TO THE REGION FROM SATURDAY NIGHT
THROUGH SUNDAY NIGHT. HIGH TEMPERATURES TODAY WILL RANGE FROM THE
UPPER TEENS ACROSS SOUTHEAST LOWER MICHIGAN TO THE UPPER 20S ACROSS
WEST CENTRAL INDIANA. LOW TEMPERATURES TONIGHT WILL DROP BACK INTO
THE TEENS.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 455 AM EST FRI JAN 30 2015

A VIGOROUS UPPER LEVEL TROUGH DROPPING ACROSS THE SOUTHERN GREAT
LAKES REGION PROVIDED SOME SYNOPTIC ENHANCEMENT TO PRECIP...BUT
STRONGER FORCING WITH THIS VORT MAX IS PROGRESSING EAST OF THE AREA
EARLY THIS MORNING. THIS WILL RESULT IN A CONTINUED TRANSITION TO
MORE OF PURE LAKE EFFECT SNOW SHOWER SCENARIO FOR THIS
MORNING...ALTHOUGH SETUP LOOKS TO BE ON THE MARGINAL SIDE.
REINFORCING LOW LEVEL CAA PUSH WITH SECONDARY SFC TROUGH PASSAGE
OVERNIGHT WILL KEEP SHALLOW BASED INSTABILITY IN PLACE FOR CONTINUED
LAKE EFFECT SNOW SHOWERS THIS MORNING...WITH INVERSION HEIGHTS
LOWERING THROUGH MID MORNING AS STRONGER SYNOPTIC SCALE SUBSIDENCE
IS ESTABLISHED IN THE WAKE OF DEPARTING UPPER LEVEL TROUGH. ANY
ACCUMULATIONS SHOULD GENERALLY BE LESS THAN AN INCH AND MAINLY
THROUGH MID TO LATE MORNING.

OTHERWISE FOR TODAY MAIN FORECAST CHALLENGE WILL BE RESOLVING SKY
COVER TRENDS. UPPER INFLECTION ZONE/LOW LEVEL ANTICYCLONE TO
OVERSPREAD THE REGION TODAY WITH EARLY MORNING GUSTY WINDS
DIMINISHING. MID LEVEL SYNOPTIC SUBSIDENCE TO CONTINUE THIS MORNING
AND ALREADY SEEING SOME DECENT EROSION OF LOW CLOUD DECK ACROSS
PORTIONS OF THE AREA. CONCERN IS THAT SHARPENING LOW LEVEL INVERSION
UNDER THE INFLUENCE OF THIS SUBSIDENCE MAY ALLOW STRATOCU TO PERSIST
THROUGH THE DAY...PARTICULARLY DOWNWIND OF LAKE MICHIGAN. RETREATING
LOW LEVEL THERMAL TROUGH WILL RESULT IN SOUTHWEST TO NORTHEAST
GRADIENT FOR MAX TEMPS TODAY RANGING FROM MID 20S SOUTHWEST TO
AROUND 20 FAR NORTHEAST. BACKING LOW LEVEL WINDS IN ASSOCIATION WITH
THE RIDGE OF HIGH PRESSURE SHOULD TAKE ANY RESIDUAL LAKE EFFECT
CLOUDINESS NORTHEASTWARD ACROSS FAR NORTHERN PORTIONS OF THE AREA
TONIGHT...WITH OVERALL TREND TO PARTLY CLOUDY/MOSTLY CLEAR SKIES AND
LIGHT WINDS ALLOWING FOR MINS TO DROP BACK INTO THE TEENS EARLY
SATURDAY MORNING.

&&

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 455 AM EST FRI JAN 30 2015

THE MAIN CHALLENGES THIS PERIOD INCLUDE THE TIMING AND TRACK OF A
SHORTWAVE TROF WELL UPSTREAM OVER ALASKA THAT WILL RACE SOUTHEAST
INTO THE WESTERN GREAT LAKES REGION. NCEP MODELS AND OTHERS HAVE
RECENTLY BEEN TRENDING NORTH WITH THIS SYSTEM. THE GARCIA/MIXING RAW
RATIO SNOWFALL FAVORS SNOWFALL AMOUNTS BETWEEN 8 AND 10 INCHES.
HOWEVER...ISSUES INCLUDING SATURATION TIME...LOW LEVEL DRY AIR
ENTRAINMENT AND CONVECTION ALONG AND SOUTH OF THE WARM FRONT MAY CUT
DEEPLY INTO SNOWFALL AMOUNTS. CURRENT THINKING IS EVENT SNOWFALL
TOTALS OF 4 TO 9 INCHES...WITH THE LOWER AMOUNTS NORTH OVER LOWER
MICHIGAN AND THE HIGHER AMOUNTS OVER NORTHERN INDIANA AND NORTHWEST
OHIO.  CIPS TOP 15 ANALOGS PAINT A SOLID 4 TO 6 INCHES OF SNOW
ACROSS THE AREA. AFTER COORDINATION WITH NEIGHBORING OFFICES...
HAVE ELECTED TO HOLD OFF ISSUING A WATCH DUE TO UNCERTAIN MODEL
HANDING OF THIS SYSTEM AMID LINGERING UNCERTAINTIES. WILL HIGHLIGHT
CONCERNS IN A SPECIAL WEATHER STATEMENT FOR NOW. OTHERWISE...MUCH
COLDER AIR WILL BE OVER THE AREA FOR THE UPCOMING WORK WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 634 AM EST FRI JAN 30 2015

LAKE EFFECT SNOW SHOWERS AND FLURRIES WILL GRADUALLY COME TO AN
END THIS MORNING AS STRONG MID LEVEL SUBSIDENCE CONTINUES TO
OVERSPREAD THE SOUTHERN GREAT LAKES. ANY ADDITIONAL SNOW
ACCUMULATION AT KSBN SHOULD ONLY TOTAL A FEW TENTHS OF AN INCH AT
MOST BEFORE DIMINISHING LATER THIS MORNING. OTHERWISE...STRENGTH
OF LOW LEVEL INVERSION MAY ALLOW HIGHER END MVFR OR VFR LOW CLOUDS
TO PERSIST THROUGH MUCH OF THE DAY BEFORE DIMINISHING TONIGHT AS
MUCH DRIER LOW LEVEL AIR MOVES INTO THE AREA IN ASSOCIATION WITH
LOW LEVEL RIDGE AXIS. WINDS WILL CONTINUE TO DIMINISH THIS MORNING
AND BACK WESTERLY THIS EVENING...AND THEN LIGHT SOUTHWESTERLY
TOWARD THE END OF THE PERIOD.

&&

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

$$

SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...SKIPPER
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 301146
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
646 AM EST FRI JAN 30 2015

.SYNOPSIS...
ISSUED AT 455 AM EST FRI JAN 30 2015

LAKE EFFECT SNOW SHOWERS WILL DIMINISH TODAY AS A RIDGE OF HIGH
PRESSURE BEGINS TO BUILD IN FROM THE WEST. THIS RIDGE OF HIGH
PRESSURE WILL DEPART TO THE EAST TONIGHT ALLOWING FOR A RETURN OF
SOUTHERLY WINDS AND MILDER CONDITIONS FOR SATURDAY. A STORM SYSTEM
WILL ORGANIZE ACROSS THE ROCKIES ON SATURDAY AND WILL BRING A GOOD
CHANCE OF ACCUMULATING SNOW TO THE REGION FROM SATURDAY NIGHT
THROUGH SUNDAY NIGHT. HIGH TEMPERATURES TODAY WILL RANGE FROM THE
UPPER TEENS ACROSS SOUTHEAST LOWER MICHIGAN TO THE UPPER 20S ACROSS
WEST CENTRAL INDIANA. LOW TEMPERATURES TONIGHT WILL DROP BACK INTO
THE TEENS.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 455 AM EST FRI JAN 30 2015

A VIGOROUS UPPER LEVEL TROUGH DROPPING ACROSS THE SOUTHERN GREAT
LAKES REGION PROVIDED SOME SYNOPTIC ENHANCEMENT TO PRECIP...BUT
STRONGER FORCING WITH THIS VORT MAX IS PROGRESSING EAST OF THE AREA
EARLY THIS MORNING. THIS WILL RESULT IN A CONTINUED TRANSITION TO
MORE OF PURE LAKE EFFECT SNOW SHOWER SCENARIO FOR THIS
MORNING...ALTHOUGH SETUP LOOKS TO BE ON THE MARGINAL SIDE.
REINFORCING LOW LEVEL CAA PUSH WITH SECONDARY SFC TROUGH PASSAGE
OVERNIGHT WILL KEEP SHALLOW BASED INSTABILITY IN PLACE FOR CONTINUED
LAKE EFFECT SNOW SHOWERS THIS MORNING...WITH INVERSION HEIGHTS
LOWERING THROUGH MID MORNING AS STRONGER SYNOPTIC SCALE SUBSIDENCE
IS ESTABLISHED IN THE WAKE OF DEPARTING UPPER LEVEL TROUGH. ANY
ACCUMULATIONS SHOULD GENERALLY BE LESS THAN AN INCH AND MAINLY
THROUGH MID TO LATE MORNING.

OTHERWISE FOR TODAY MAIN FORECAST CHALLENGE WILL BE RESOLVING SKY
COVER TRENDS. UPPER INFLECTION ZONE/LOW LEVEL ANTICYCLONE TO
OVERSPREAD THE REGION TODAY WITH EARLY MORNING GUSTY WINDS
DIMINISHING. MID LEVEL SYNOPTIC SUBSIDENCE TO CONTINUE THIS MORNING
AND ALREADY SEEING SOME DECENT EROSION OF LOW CLOUD DECK ACROSS
PORTIONS OF THE AREA. CONCERN IS THAT SHARPENING LOW LEVEL INVERSION
UNDER THE INFLUENCE OF THIS SUBSIDENCE MAY ALLOW STRATOCU TO PERSIST
THROUGH THE DAY...PARTICULARLY DOWNWIND OF LAKE MICHIGAN. RETREATING
LOW LEVEL THERMAL TROUGH WILL RESULT IN SOUTHWEST TO NORTHEAST
GRADIENT FOR MAX TEMPS TODAY RANGING FROM MID 20S SOUTHWEST TO
AROUND 20 FAR NORTHEAST. BACKING LOW LEVEL WINDS IN ASSOCIATION WITH
THE RIDGE OF HIGH PRESSURE SHOULD TAKE ANY RESIDUAL LAKE EFFECT
CLOUDINESS NORTHEASTWARD ACROSS FAR NORTHERN PORTIONS OF THE AREA
TONIGHT...WITH OVERALL TREND TO PARTLY CLOUDY/MOSTLY CLEAR SKIES AND
LIGHT WINDS ALLOWING FOR MINS TO DROP BACK INTO THE TEENS EARLY
SATURDAY MORNING.

&&

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 455 AM EST FRI JAN 30 2015

THE MAIN CHALLENGES THIS PERIOD INCLUDE THE TIMING AND TRACK OF A
SHORTWAVE TROF WELL UPSTREAM OVER ALASKA THAT WILL RACE SOUTHEAST
INTO THE WESTERN GREAT LAKES REGION. NCEP MODELS AND OTHERS HAVE
RECENTLY BEEN TRENDING NORTH WITH THIS SYSTEM. THE GARCIA/MIXING RAW
RATIO SNOWFALL FAVORS SNOWFALL AMOUNTS BETWEEN 8 AND 10 INCHES.
HOWEVER...ISSUES INCLUDING SATURATION TIME...LOW LEVEL DRY AIR
ENTRAINMENT AND CONVECTION ALONG AND SOUTH OF THE WARM FRONT MAY CUT
DEEPLY INTO SNOWFALL AMOUNTS. CURRENT THINKING IS EVENT SNOWFALL
TOTALS OF 4 TO 9 INCHES...WITH THE LOWER AMOUNTS NORTH OVER LOWER
MICHIGAN AND THE HIGHER AMOUNTS OVER NORTHERN INDIANA AND NORTHWEST
OHIO.  CIPS TOP 15 ANALOGS PAINT A SOLID 4 TO 6 INCHES OF SNOW
ACROSS THE AREA. AFTER COORDINATION WITH NEIGHBORING OFFICES...
HAVE ELECTED TO HOLD OFF ISSUING A WATCH DUE TO UNCERTAIN MODEL
HANDING OF THIS SYSTEM AMID LINGERING UNCERTAINTIES. WILL HIGHLIGHT
CONCERNS IN A SPECIAL WEATHER STATEMENT FOR NOW. OTHERWISE...MUCH
COLDER AIR WILL BE OVER THE AREA FOR THE UPCOMING WORK WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 634 AM EST FRI JAN 30 2015

LAKE EFFECT SNOW SHOWERS AND FLURRIES WILL GRADUALLY COME TO AN
END THIS MORNING AS STRONG MID LEVEL SUBSIDENCE CONTINUES TO
OVERSPREAD THE SOUTHERN GREAT LAKES. ANY ADDITIONAL SNOW
ACCUMULATION AT KSBN SHOULD ONLY TOTAL A FEW TENTHS OF AN INCH AT
MOST BEFORE DIMINISHING LATER THIS MORNING. OTHERWISE...STRENGTH
OF LOW LEVEL INVERSION MAY ALLOW HIGHER END MVFR OR VFR LOW CLOUDS
TO PERSIST THROUGH MUCH OF THE DAY BEFORE DIMINISHING TONIGHT AS
MUCH DRIER LOW LEVEL AIR MOVES INTO THE AREA IN ASSOCIATION WITH
LOW LEVEL RIDGE AXIS. WINDS WILL CONTINUE TO DIMINISH THIS MORNING
AND BACK WESTERLY THIS EVENING...AND THEN LIGHT SOUTHWESTERLY
TOWARD THE END OF THE PERIOD.

&&

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

$$

SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...SKIPPER
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 300957
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
457 AM EST FRI JAN 30 2015

.SYNOPSIS...
ISSUED AT 455 AM EST FRI JAN 30 2015

LAKE EFFECT SNOW SHOWERS WILL DIMINISH TODAY AS A RIDGE OF HIGH
PRESSURE BEGINS TO BUILD IN FROM THE WEST. THIS RIDGE OF HIGH
PRESSURE WILL DEPART TO THE EAST TONIGHT ALLOWING FOR A RETURN OF
SOUTHERLY WINDS AND MILDER CONDITIONS FOR SATURDAY. A STORM SYSTEM
WILL ORGANIZE ACROSS THE ROCKIES ON SATURDAY AND WILL BRING A GOOD
CHANCE OF ACCUMULATING SNOW TO THE REGION FROM SATURDAY NIGHT
THROUGH SUNDAY NIGHT. HIGH TEMPERATURES TODAY WILL RANGE FROM THE
UPPER TEENS ACROSS SOUTHEAST LOWER MICHIGAN TO THE UPPER 20S ACROSS
WEST CENTRAL INDIANA. LOW TEMPERATURES TONIGHT WILL DROP BACK INTO
THE TEENS.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 455 AM EST FRI JAN 30 2015

A VIGOROUS UPPER LEVEL TROUGH DROPPING ACROSS THE SOUTHERN GREAT
LAKES REGION PROVIDED SOME SYNOPTIC ENHANCEMENT TO PRECIP...BUT
STRONGER FORCING WITH THIS VORT MAX IS PROGRESSING EAST OF THE AREA
EARLY THIS MORNING. THIS WILL RESULT IN A CONTINUED TRANSITION TO
MORE OF PURE LAKE EFFECT SNOW SHOWER SCENARIO FOR THIS
MORNING...ALTHOUGH SETUP LOOKS TO BE ON THE MARGINAL SIDE.
REINFORCING LOW LEVEL CAA PUSH WITH SECONDARY SFC TROUGH PASSAGE
OVERNIGHT WILL KEEP SHALLOW BASED INSTABILITY IN PLACE FOR CONTINUED
LAKE EFFECT SNOW SHOWERS THIS MORNING...WITH INVERSION HEIGHTS
LOWERING THROUGH MID MORNING AS STRONGER SYNOPTIC SCALE SUBSIDENCE
IS ESTABLISHED IN THE WAKE OF DEPARTING UPPER LEVEL TROUGH. ANY
ACCUMULATIONS SHOULD GENERALLY BE LESS THAN AN INCH AND MAINLY
THROUGH MID TO LATE MORNING.

OTHERWISE FOR TODAY MAIN FORECAST CHALLENGE WILL BE RESOLVING SKY
COVER TRENDS. UPPER INFLECTION ZONE/LOW LEVEL ANTICYCLONE TO
OVERSPREAD THE REGION TODAY WITH EARLY MORNING GUSTY WINDS
DIMINISHING. MID LEVEL SYNOPTIC SUBSIDENCE TO CONTINUE THIS MORNING
AND ALREADY SEEING SOME DECENT EROSION OF LOW CLOUD DECK ACROSS
PORTIONS OF THE AREA. CONCERN IS THAT SHARPENING LOW LEVEL INVERSION
UNDER THE INFLUENCE OF THIS SUBSIDENCE MAY ALLOW STRATOCU TO PERSIST
THROUGH THE DAY...PARTICULARLY DOWNWIND OF LAKE MICHIGAN. RETREATING
LOW LEVEL THERMAL TROUGH WILL RESULT IN SOUTHWEST TO NORTHEAST
GRADIENT FOR MAX TEMPS TODAY RANGING FROM MID 20S SOUTHWEST TO
AROUND 20 FAR NORTHEAST. BACKING LOW LEVEL WINDS IN ASSOCIATION WITH
THE RIDGE OF HIGH PRESSURE SHOULD TAKE ANY RESIDUAL LAKE EFFECT
CLOUDINESS NORTHEASTWARD ACROSS FAR NORTHERN PORTIONS OF THE AREA
TONIGHT...WITH OVERALL TREND TO PARTLY CLOUDY/MOSTLY CLEAR SKIES AND
LIGHT WINDS ALLOWING FOR MINS TO DROP BACK INTO THE TEENS EARLY
SATURDAY MORNING.

&&

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 455 AM EST FRI JAN 30 2015

THE MAIN CHALLENGES THIS PERIOD INCLUDE THE TIMING AND TRACK OF A
SHORTWAVE TROF WELL UPSTREAM OVER ALASKA THAT WILL RACE SOUTHEAST
INTO THE WESTERN GREAT LAKES REGION. NCEP MODELS AND OTHERS HAVE
RECENTLY BEEN TRENDING NORTH WITH THIS SYSTEM. THE GARCIA/MIXING RAW
RATIO SNOWFALL FAVORS SNOWFALL AMOUNTS BETWEEN 8 AND 10 INCHES.
HOWEVER...ISSUES INCLUDING SATURATION TIME...LOW LEVEL DRY AIR
ENTRAINMENT AND CONVECTION ALONG AND SOUTH OF THE WARM FRONT MAY CUT
DEEPLY INTO SNOWFALL AMOUNTS. CURRENT THINKING IS EVENT SNOWFALL
TOTALS OF 4 TO 9 INCHES...WITH THE LOWER AMOUNTS NORTH OVER LOWER
MICHIGAN AND THE HIGHER AMOUNTS OVER NORTHERN INDIANA AND NORTHWEST
OHIO.  CIPS TOP 15 ANALOGS PAINT A SOLID 4 TO 6 INCHES OF SNOW
ACROSS THE AREA. AFTER COORDINATION WITH NEIGHBORING OFFICES...
HAVE ELECTED TO HOLD OFF ISSUING A WATCH DUE TO UNCERTAIN MODEL
HANDING OF THIS SYSTEM AMID LINGERING UNCERTAINTIES. WILL HIGHLIGHT
CONCERNS IN A SPECIAL WEATHER STATEMENT FOR NOW. OTHERWISE...MUCH
COLDER AIR WILL BE OVER THE AREA FOR THE UPCOMING WORK WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 123 AM EST FRI JAN 30 2015

SCATTERED SNOW SHOWERS TO CONTINUE OVER THE NEXT SEVERAL
HOURS...WITH TRANSITION TO MORE PURE LAKE EFFECT SNOW SHOWERS
AFTER 09Z. A STRONG UPPER VORT MAX DROPPING ACROSS THE SOUTHERN
GREAT LAKES REGION HAS ENHANCED COVERAGE/INTENSITY OF SCATTERED
SNOW SHOWERS ACROSS THE REGION. STRONGEST FORCING WITH THIS SHORT
WAVE WILL SLIP EAST OF THE TERMINALS AFTER 09Z...WITH CONTINUED
SCATTERED SNOW SHOWERS EXPECTED TO AFFECT KSBN THROUGH FRIDAY
MORNING. WILL MAINTAIN PRIMARILY MVFR CONDITIONS WITH THE PERIODIC
SNOW SHOWERS AT KSBN...ALTHOUGH VERY BRIEF PERIODS OF IFR VSBYS
ARE POSSIBLE WITH THE HEAVIER SNOW SHOWERS. INTENSITY OF LAKE
EFFECT SNOW SHOWERS SHOULD DIMINISH AFTER 12Z AS INVERSION HEIGHTS
CONTINUE TO LOWER...WITH TOTAL ACCUMULATIONS AT KSBN GENERALLY
LESS THAN AN INCH EXPECTED. A REINFORCING SURFACE TROUGH
ACCOMPANYING THIS STRONGER UPPER VORT MAX WILL CONTINUE TO ALLOW
FOR A PERIOD OF NORTHWEST WIND GUSTS AROUND 25 KNOTS...WHICH
SHOULD SLOWLY DIMINISH TOWARD DAYBREAK. CIGS IN THE 2500-3500 FT
RANGE MAY PERSIST INTO MUCH OF FRIDAY AS SYNOPTIC SUBSIDENCE
STRENGTHENS LOW LEVEL INVERSION HELPING TO TRAP LOW CLOUDS.

&&

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

$$

SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...SKIPPER
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 300957
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
457 AM EST FRI JAN 30 2015

.SYNOPSIS...
ISSUED AT 455 AM EST FRI JAN 30 2015

LAKE EFFECT SNOW SHOWERS WILL DIMINISH TODAY AS A RIDGE OF HIGH
PRESSURE BEGINS TO BUILD IN FROM THE WEST. THIS RIDGE OF HIGH
PRESSURE WILL DEPART TO THE EAST TONIGHT ALLOWING FOR A RETURN OF
SOUTHERLY WINDS AND MILDER CONDITIONS FOR SATURDAY. A STORM SYSTEM
WILL ORGANIZE ACROSS THE ROCKIES ON SATURDAY AND WILL BRING A GOOD
CHANCE OF ACCUMULATING SNOW TO THE REGION FROM SATURDAY NIGHT
THROUGH SUNDAY NIGHT. HIGH TEMPERATURES TODAY WILL RANGE FROM THE
UPPER TEENS ACROSS SOUTHEAST LOWER MICHIGAN TO THE UPPER 20S ACROSS
WEST CENTRAL INDIANA. LOW TEMPERATURES TONIGHT WILL DROP BACK INTO
THE TEENS.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 455 AM EST FRI JAN 30 2015

A VIGOROUS UPPER LEVEL TROUGH DROPPING ACROSS THE SOUTHERN GREAT
LAKES REGION PROVIDED SOME SYNOPTIC ENHANCEMENT TO PRECIP...BUT
STRONGER FORCING WITH THIS VORT MAX IS PROGRESSING EAST OF THE AREA
EARLY THIS MORNING. THIS WILL RESULT IN A CONTINUED TRANSITION TO
MORE OF PURE LAKE EFFECT SNOW SHOWER SCENARIO FOR THIS
MORNING...ALTHOUGH SETUP LOOKS TO BE ON THE MARGINAL SIDE.
REINFORCING LOW LEVEL CAA PUSH WITH SECONDARY SFC TROUGH PASSAGE
OVERNIGHT WILL KEEP SHALLOW BASED INSTABILITY IN PLACE FOR CONTINUED
LAKE EFFECT SNOW SHOWERS THIS MORNING...WITH INVERSION HEIGHTS
LOWERING THROUGH MID MORNING AS STRONGER SYNOPTIC SCALE SUBSIDENCE
IS ESTABLISHED IN THE WAKE OF DEPARTING UPPER LEVEL TROUGH. ANY
ACCUMULATIONS SHOULD GENERALLY BE LESS THAN AN INCH AND MAINLY
THROUGH MID TO LATE MORNING.

OTHERWISE FOR TODAY MAIN FORECAST CHALLENGE WILL BE RESOLVING SKY
COVER TRENDS. UPPER INFLECTION ZONE/LOW LEVEL ANTICYCLONE TO
OVERSPREAD THE REGION TODAY WITH EARLY MORNING GUSTY WINDS
DIMINISHING. MID LEVEL SYNOPTIC SUBSIDENCE TO CONTINUE THIS MORNING
AND ALREADY SEEING SOME DECENT EROSION OF LOW CLOUD DECK ACROSS
PORTIONS OF THE AREA. CONCERN IS THAT SHARPENING LOW LEVEL INVERSION
UNDER THE INFLUENCE OF THIS SUBSIDENCE MAY ALLOW STRATOCU TO PERSIST
THROUGH THE DAY...PARTICULARLY DOWNWIND OF LAKE MICHIGAN. RETREATING
LOW LEVEL THERMAL TROUGH WILL RESULT IN SOUTHWEST TO NORTHEAST
GRADIENT FOR MAX TEMPS TODAY RANGING FROM MID 20S SOUTHWEST TO
AROUND 20 FAR NORTHEAST. BACKING LOW LEVEL WINDS IN ASSOCIATION WITH
THE RIDGE OF HIGH PRESSURE SHOULD TAKE ANY RESIDUAL LAKE EFFECT
CLOUDINESS NORTHEASTWARD ACROSS FAR NORTHERN PORTIONS OF THE AREA
TONIGHT...WITH OVERALL TREND TO PARTLY CLOUDY/MOSTLY CLEAR SKIES AND
LIGHT WINDS ALLOWING FOR MINS TO DROP BACK INTO THE TEENS EARLY
SATURDAY MORNING.

&&

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 455 AM EST FRI JAN 30 2015

THE MAIN CHALLENGES THIS PERIOD INCLUDE THE TIMING AND TRACK OF A
SHORTWAVE TROF WELL UPSTREAM OVER ALASKA THAT WILL RACE SOUTHEAST
INTO THE WESTERN GREAT LAKES REGION. NCEP MODELS AND OTHERS HAVE
RECENTLY BEEN TRENDING NORTH WITH THIS SYSTEM. THE GARCIA/MIXING RAW
RATIO SNOWFALL FAVORS SNOWFALL AMOUNTS BETWEEN 8 AND 10 INCHES.
HOWEVER...ISSUES INCLUDING SATURATION TIME...LOW LEVEL DRY AIR
ENTRAINMENT AND CONVECTION ALONG AND SOUTH OF THE WARM FRONT MAY CUT
DEEPLY INTO SNOWFALL AMOUNTS. CURRENT THINKING IS EVENT SNOWFALL
TOTALS OF 4 TO 9 INCHES...WITH THE LOWER AMOUNTS NORTH OVER LOWER
MICHIGAN AND THE HIGHER AMOUNTS OVER NORTHERN INDIANA AND NORTHWEST
OHIO.  CIPS TOP 15 ANALOGS PAINT A SOLID 4 TO 6 INCHES OF SNOW
ACROSS THE AREA. AFTER COORDINATION WITH NEIGHBORING OFFICES...
HAVE ELECTED TO HOLD OFF ISSUING A WATCH DUE TO UNCERTAIN MODEL
HANDING OF THIS SYSTEM AMID LINGERING UNCERTAINTIES. WILL HIGHLIGHT
CONCERNS IN A SPECIAL WEATHER STATEMENT FOR NOW. OTHERWISE...MUCH
COLDER AIR WILL BE OVER THE AREA FOR THE UPCOMING WORK WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 123 AM EST FRI JAN 30 2015

SCATTERED SNOW SHOWERS TO CONTINUE OVER THE NEXT SEVERAL
HOURS...WITH TRANSITION TO MORE PURE LAKE EFFECT SNOW SHOWERS
AFTER 09Z. A STRONG UPPER VORT MAX DROPPING ACROSS THE SOUTHERN
GREAT LAKES REGION HAS ENHANCED COVERAGE/INTENSITY OF SCATTERED
SNOW SHOWERS ACROSS THE REGION. STRONGEST FORCING WITH THIS SHORT
WAVE WILL SLIP EAST OF THE TERMINALS AFTER 09Z...WITH CONTINUED
SCATTERED SNOW SHOWERS EXPECTED TO AFFECT KSBN THROUGH FRIDAY
MORNING. WILL MAINTAIN PRIMARILY MVFR CONDITIONS WITH THE PERIODIC
SNOW SHOWERS AT KSBN...ALTHOUGH VERY BRIEF PERIODS OF IFR VSBYS
ARE POSSIBLE WITH THE HEAVIER SNOW SHOWERS. INTENSITY OF LAKE
EFFECT SNOW SHOWERS SHOULD DIMINISH AFTER 12Z AS INVERSION HEIGHTS
CONTINUE TO LOWER...WITH TOTAL ACCUMULATIONS AT KSBN GENERALLY
LESS THAN AN INCH EXPECTED. A REINFORCING SURFACE TROUGH
ACCOMPANYING THIS STRONGER UPPER VORT MAX WILL CONTINUE TO ALLOW
FOR A PERIOD OF NORTHWEST WIND GUSTS AROUND 25 KNOTS...WHICH
SHOULD SLOWLY DIMINISH TOWARD DAYBREAK. CIGS IN THE 2500-3500 FT
RANGE MAY PERSIST INTO MUCH OF FRIDAY AS SYNOPTIC SUBSIDENCE
STRENGTHENS LOW LEVEL INVERSION HELPING TO TRAP LOW CLOUDS.

&&

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

$$

SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...SKIPPER
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 300631
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
131 AM EST FRI JAN 30 2015

.SYNOPSIS...
ISSUED AT 408 PM EST THU JAN 29 2015

COLDER AIR WILL MOVE IN ACROSS THE GREAT LAKES OVER THE NEXT 24
HOURS. LAKE EFFECT SNOW SHOWERS WILL IMPACT PORTIONS OF NORTHERN
INDIANA AND SOUTHWESTERN LOWER MICHIGAN INTO FRIDAY AFTERNOON
BEFORE DIMINISHING. LOWS TONIGHT WILL RANGE FROM THE MIDDLE 20S
WHERE LAKE EFFECT CLOUDS PERSIST...TO THE MIDDLE TEENS ELSEWHERE.
TEMPERATURES WILL RISE LITTLE ON FRIDAY WITH HIGHS IN THE LOWER TO
MIDDLE 20S.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 408 PM EST THU JAN 29 2015

FIRST OF 3 WAVES WAS NOW MOVING THROUGH WESTERN OHIO WITH AN AREA OF
RAIN JUST AHEAD OF IT. NW WINDS WERE NOW BLOWING ACROSS MUCH OF THE
AREA WITH SOME GUSTS IN THE 25 TO 30 MPH RANGE. BEHIND THE
WAVE...PRECIP HAS WENT TO MORE OF A FLURRY/DRIZZLE SETUP AS ICE
PRODUCTION AND DEEPER LIFT APPEARS TO HAVE DEPARTED FOR THE MOMENT.
THIS WILL BE SHORT LIVED AS NEXT WAVE WAS RIGHT ON ITS HEELS
CURRENTLY WRAPPING UP OVER EAST IOWA/NW ILLINOIS BRINGS IN COLDER
LOW LEVEL TEMPS AND TRANSITION TO ALL SNOW FOR WHATEVER IS LEFT
OVER. LAKE EFFECT SNOW SHOWERS WILL MATERIALIZE LATE AFTERNOON INTO
THIS EVENING...BUT REMAIN WEAK AND DISORGANIZED AS MARGINAL DELTA
T`S PREVAIL. ENOUGH DEVELOPMENT SHOULD EXIST TO STILL WARRANT LIKELY
POPS DOWNWIND OF THE LAKE FOR THIS EVENING.

LAST WAVE...CURRENTLY ENTERING NORTHERN MINNESOTA...WILL RAPIDLY
DROP SOUTHEAST AND IMPACT THE REGION LATER TONIGHT INTO FRIDAY. BEST
LAKE EFFECT CHANCES WILL ARRIVE WITH THIS FEATURE AS 850 MB TEMPS
DROP TO -14 TO -16 C BY 12Z FRIDAY. A FAVORABLE FETCH DOWN THE WEST
PART OF THE LAKE CURVING EAST WOULD ALLOW FOR SOME STRONGER BAND
POTENTIAL. INVERSION HGTS WILL PEAK AROUND 7 KFT BRIEFLY BEHIND THE
WAVE BUT CO LOCATION WITH DGZ AND BEST LIFT WILL NEVER FULLY
COINCIDE. IN ADDITION...BANDS WILL LIKELY BE MOVING AROUND AS FLOW
VARIES BETWEEN 310 AND 330 DEGREES MUCH OF THE EVENT. ALL THESE
FACTORS SHOULD LIMIT AND THEN SLOWLY FALL. THIS SHOULD LIMIT
ACCUMULATIONS TO THE 1 TO 2 INCH RANGE.

IN TERMS OF TEMPERATURES...LOWS WILL DROP OFF INTO THE TEENS LATER
TONIGHT FOR MOST LOCATIONS WITH AREAS SHELTERED BY LAKE EFFECT
CLOUDS DROPPING IN THE LOWER TO MIDDLE 20S. ONLY A MINOR DIURNAL
SWING IN TEMPS IS EXPECTED ON FRIDAY.

&&

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 408 PM EST THU JAN 29 2015

COMPLEX AND VIGOROUS UPSTREAM INTERACTION BETWEEN MULTITUDE OF
SHORTWAVES BEGINNING TO CONVERGE INTERMODEL CONSENSUS. SURFACE RIDGE
OVHD FRIDAY EVENING WITH WEAK CLIPPER SYSTEM PUSHING SEWD THROUGH
NRN PLAINS. MOISTURE LACKING WITH BNDRY CONTG TO SLIDE SEWD THROUGH
GRTLKS SAT. FURTIVE SWD DIG OF HEIGHT FALL CENTROID TOWARD BAJA
CUTOFF SUPPORTING FARTHER SWD CYCLOGENESIS EMANATING OUT OF ARKLATEX
SUN AND INTO TN VALLEY SUN NIGHT. STILL STRONG OPEN/POSITIVE TILTED
7H WAVE WITH NRN FRINGE OF HFC PROVIDING 100-120M/12 HR HEIGHT
ADJUSTMENTS CARVES THROUGH SRN TIER CWA. HAVE MUTED POPS 00-06 UTC
SUNDAY WITH CONCERNS OF MODELS A BIT FAST IN OVERCOMING PRIOR
100-150MB LOW LEVEL CONDENSATION PRESSURE DEFICITS...BUT THEN RAMP
RAPIDLY BY 12 UTC. WHILE ENTIRE EVENT I280-285K ISENT UPGLIDE NOT
ASTOUNDING...THOUGH SYSTEM RELATIVE FLOW ESPECIALLY IN LWR LEVELS
ALONG WITH SIG MOISTURE FLUX CONVERGENCE INTO FAR SRN TIER CWA.
RAMPED POPS SUN...ESPECIALLY FAR SRN TIER ANTICIPATORY OF BEING ON
NRN FRINGE OF MARKED SNOWFALL GRADIENT. RICH BULK MOISTURE AROUND 3
G/KG 1000-850MB LAYER SUN ACRS SRN CWA...GRADUALLY LOWERS TO 2 G/KG
BY LATE AFTN/EVE AS SURFACE RESPONSE TIGHTENS SIGNIFICANTLY AND WELL
SOUTH OF CWA. BRIEF LES RESPONSE SUN NIGHT THOUGH QUICKLY ENDING
MONDAY AS PRIMARY SYSTEM FURTHER DEEPENS OFF MID ATL COAST...DRAWING
DRIER AIR/LOW SUBSIDENCE INVERSION THROUGH WRN GRLKS. WEAK CLIPPER
SYSTEM PSBL TUE/TUE NIGHT...FOLLOWED BY MEAGER LAKE RESPONSE INTO
MIDWEEK AS TROF SHARPENS THROUGH LWR GRTLKS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 123 AM EST FRI JAN 30 2015

SCATTERED SNOW SHOWERS TO CONTINUE OVER THE NEXT SEVERAL
HOURS...WITH TRANSITION TO MORE PURE LAKE EFFECT SNOW SHOWERS
AFTER 09Z. A STRONG UPPER VORT MAX DROPPING ACROSS THE SOUTHERN
GREAT LAKES REGION HAS ENHANCED COVERAGE/INTENSITY OF SCATTERED
SNOW SHOWERS ACROSS THE REGION. STRONGEST FORCING WITH THIS SHORT
WAVE WILL SLIP EAST OF THE TERMINALS AFTER 09Z...WITH CONTINUED
SCATTERED SNOW SHOWERS EXPECTED TO AFFECT KSBN THROUGH FRIDAY
MORNING. WILL MAINTAIN PRIMARILY MVFR CONDITIONS WITH THE PERIODIC
SNOW SHOWERS AT KSBN...ALTHOUGH VERY BRIEF PERIODS OF IFR VSBYS
ARE POSSIBLE WITH THE HEAVIER SNOW SHOWERS. INTENSITY OF LAKE
EFFECT SNOW SHOWERS SHOULD DIMINISH AFTER 12Z AS INVERSION HEIGHTS
CONTINUE TO LOWER...WITH TOTAL ACCUMULATIONS AT KSBN GENERALLY
LESS THAN AN INCH EXPECTED. A REINFORCING SURFACE TROUGH
ACCOMPANYING THIS STRONGER UPPER VORT MAX WILL CONTINUE TO ALLOW
FOR A PERIOD OF NORTHWEST WIND GUSTS AROUND 25 KNOTS...WHICH
SHOULD SLOWLY DIMINISH TOWARD DAYBREAK. CIGS IN THE 2500-3500 FT
RANGE MAY PERSIST INTO MUCH OF FRIDAY AS SYNOPTIC SUBSIDENCE
STRENGTHENS LOW LEVEL INVERSION HELPING TO TRAP LOW CLOUDS.

&&

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

$$

SYNOPSIS...FISHER
SHORT TERM...FISHER
LONG TERM...MURPHY
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 300631
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
131 AM EST FRI JAN 30 2015

.SYNOPSIS...
ISSUED AT 408 PM EST THU JAN 29 2015

COLDER AIR WILL MOVE IN ACROSS THE GREAT LAKES OVER THE NEXT 24
HOURS. LAKE EFFECT SNOW SHOWERS WILL IMPACT PORTIONS OF NORTHERN
INDIANA AND SOUTHWESTERN LOWER MICHIGAN INTO FRIDAY AFTERNOON
BEFORE DIMINISHING. LOWS TONIGHT WILL RANGE FROM THE MIDDLE 20S
WHERE LAKE EFFECT CLOUDS PERSIST...TO THE MIDDLE TEENS ELSEWHERE.
TEMPERATURES WILL RISE LITTLE ON FRIDAY WITH HIGHS IN THE LOWER TO
MIDDLE 20S.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 408 PM EST THU JAN 29 2015

FIRST OF 3 WAVES WAS NOW MOVING THROUGH WESTERN OHIO WITH AN AREA OF
RAIN JUST AHEAD OF IT. NW WINDS WERE NOW BLOWING ACROSS MUCH OF THE
AREA WITH SOME GUSTS IN THE 25 TO 30 MPH RANGE. BEHIND THE
WAVE...PRECIP HAS WENT TO MORE OF A FLURRY/DRIZZLE SETUP AS ICE
PRODUCTION AND DEEPER LIFT APPEARS TO HAVE DEPARTED FOR THE MOMENT.
THIS WILL BE SHORT LIVED AS NEXT WAVE WAS RIGHT ON ITS HEELS
CURRENTLY WRAPPING UP OVER EAST IOWA/NW ILLINOIS BRINGS IN COLDER
LOW LEVEL TEMPS AND TRANSITION TO ALL SNOW FOR WHATEVER IS LEFT
OVER. LAKE EFFECT SNOW SHOWERS WILL MATERIALIZE LATE AFTERNOON INTO
THIS EVENING...BUT REMAIN WEAK AND DISORGANIZED AS MARGINAL DELTA
T`S PREVAIL. ENOUGH DEVELOPMENT SHOULD EXIST TO STILL WARRANT LIKELY
POPS DOWNWIND OF THE LAKE FOR THIS EVENING.

LAST WAVE...CURRENTLY ENTERING NORTHERN MINNESOTA...WILL RAPIDLY
DROP SOUTHEAST AND IMPACT THE REGION LATER TONIGHT INTO FRIDAY. BEST
LAKE EFFECT CHANCES WILL ARRIVE WITH THIS FEATURE AS 850 MB TEMPS
DROP TO -14 TO -16 C BY 12Z FRIDAY. A FAVORABLE FETCH DOWN THE WEST
PART OF THE LAKE CURVING EAST WOULD ALLOW FOR SOME STRONGER BAND
POTENTIAL. INVERSION HGTS WILL PEAK AROUND 7 KFT BRIEFLY BEHIND THE
WAVE BUT CO LOCATION WITH DGZ AND BEST LIFT WILL NEVER FULLY
COINCIDE. IN ADDITION...BANDS WILL LIKELY BE MOVING AROUND AS FLOW
VARIES BETWEEN 310 AND 330 DEGREES MUCH OF THE EVENT. ALL THESE
FACTORS SHOULD LIMIT AND THEN SLOWLY FALL. THIS SHOULD LIMIT
ACCUMULATIONS TO THE 1 TO 2 INCH RANGE.

IN TERMS OF TEMPERATURES...LOWS WILL DROP OFF INTO THE TEENS LATER
TONIGHT FOR MOST LOCATIONS WITH AREAS SHELTERED BY LAKE EFFECT
CLOUDS DROPPING IN THE LOWER TO MIDDLE 20S. ONLY A MINOR DIURNAL
SWING IN TEMPS IS EXPECTED ON FRIDAY.

&&

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 408 PM EST THU JAN 29 2015

COMPLEX AND VIGOROUS UPSTREAM INTERACTION BETWEEN MULTITUDE OF
SHORTWAVES BEGINNING TO CONVERGE INTERMODEL CONSENSUS. SURFACE RIDGE
OVHD FRIDAY EVENING WITH WEAK CLIPPER SYSTEM PUSHING SEWD THROUGH
NRN PLAINS. MOISTURE LACKING WITH BNDRY CONTG TO SLIDE SEWD THROUGH
GRTLKS SAT. FURTIVE SWD DIG OF HEIGHT FALL CENTROID TOWARD BAJA
CUTOFF SUPPORTING FARTHER SWD CYCLOGENESIS EMANATING OUT OF ARKLATEX
SUN AND INTO TN VALLEY SUN NIGHT. STILL STRONG OPEN/POSITIVE TILTED
7H WAVE WITH NRN FRINGE OF HFC PROVIDING 100-120M/12 HR HEIGHT
ADJUSTMENTS CARVES THROUGH SRN TIER CWA. HAVE MUTED POPS 00-06 UTC
SUNDAY WITH CONCERNS OF MODELS A BIT FAST IN OVERCOMING PRIOR
100-150MB LOW LEVEL CONDENSATION PRESSURE DEFICITS...BUT THEN RAMP
RAPIDLY BY 12 UTC. WHILE ENTIRE EVENT I280-285K ISENT UPGLIDE NOT
ASTOUNDING...THOUGH SYSTEM RELATIVE FLOW ESPECIALLY IN LWR LEVELS
ALONG WITH SIG MOISTURE FLUX CONVERGENCE INTO FAR SRN TIER CWA.
RAMPED POPS SUN...ESPECIALLY FAR SRN TIER ANTICIPATORY OF BEING ON
NRN FRINGE OF MARKED SNOWFALL GRADIENT. RICH BULK MOISTURE AROUND 3
G/KG 1000-850MB LAYER SUN ACRS SRN CWA...GRADUALLY LOWERS TO 2 G/KG
BY LATE AFTN/EVE AS SURFACE RESPONSE TIGHTENS SIGNIFICANTLY AND WELL
SOUTH OF CWA. BRIEF LES RESPONSE SUN NIGHT THOUGH QUICKLY ENDING
MONDAY AS PRIMARY SYSTEM FURTHER DEEPENS OFF MID ATL COAST...DRAWING
DRIER AIR/LOW SUBSIDENCE INVERSION THROUGH WRN GRLKS. WEAK CLIPPER
SYSTEM PSBL TUE/TUE NIGHT...FOLLOWED BY MEAGER LAKE RESPONSE INTO
MIDWEEK AS TROF SHARPENS THROUGH LWR GRTLKS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 123 AM EST FRI JAN 30 2015

SCATTERED SNOW SHOWERS TO CONTINUE OVER THE NEXT SEVERAL
HOURS...WITH TRANSITION TO MORE PURE LAKE EFFECT SNOW SHOWERS
AFTER 09Z. A STRONG UPPER VORT MAX DROPPING ACROSS THE SOUTHERN
GREAT LAKES REGION HAS ENHANCED COVERAGE/INTENSITY OF SCATTERED
SNOW SHOWERS ACROSS THE REGION. STRONGEST FORCING WITH THIS SHORT
WAVE WILL SLIP EAST OF THE TERMINALS AFTER 09Z...WITH CONTINUED
SCATTERED SNOW SHOWERS EXPECTED TO AFFECT KSBN THROUGH FRIDAY
MORNING. WILL MAINTAIN PRIMARILY MVFR CONDITIONS WITH THE PERIODIC
SNOW SHOWERS AT KSBN...ALTHOUGH VERY BRIEF PERIODS OF IFR VSBYS
ARE POSSIBLE WITH THE HEAVIER SNOW SHOWERS. INTENSITY OF LAKE
EFFECT SNOW SHOWERS SHOULD DIMINISH AFTER 12Z AS INVERSION HEIGHTS
CONTINUE TO LOWER...WITH TOTAL ACCUMULATIONS AT KSBN GENERALLY
LESS THAN AN INCH EXPECTED. A REINFORCING SURFACE TROUGH
ACCOMPANYING THIS STRONGER UPPER VORT MAX WILL CONTINUE TO ALLOW
FOR A PERIOD OF NORTHWEST WIND GUSTS AROUND 25 KNOTS...WHICH
SHOULD SLOWLY DIMINISH TOWARD DAYBREAK. CIGS IN THE 2500-3500 FT
RANGE MAY PERSIST INTO MUCH OF FRIDAY AS SYNOPTIC SUBSIDENCE
STRENGTHENS LOW LEVEL INVERSION HELPING TO TRAP LOW CLOUDS.

&&

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

$$

SYNOPSIS...FISHER
SHORT TERM...FISHER
LONG TERM...MURPHY
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 300028
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
728 PM EST THU JAN 29 2015

.SYNOPSIS...
ISSUED AT 408 PM EST THU JAN 29 2015

COLDER AIR WILL MOVE IN ACROSS THE GREAT LAKES OVER THE NEXT 24
HOURS. LAKE EFFECT SNOW SHOWERS WILL IMPACT PORTIONS OF NORTHERN
INDIANA AND SOUTHWESTERN LOWER MICHIGAN INTO FRIDAY AFTERNOON
BEFORE DIMINISHING. LOWS TONIGHT WILL RANGE FROM THE MIDDLE 20S
WHERE LAKE EFFECT CLOUDS PERSIST...TO THE MIDDLE TEENS ELSEWHERE.
TEMPERATURES WILL RISE LITTLE ON FRIDAY WITH HIGHS IN THE LOWER TO
MIDDLE 20S.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 408 PM EST THU JAN 29 2015

FIRST OF 3 WAVES WAS NOW MOVING THROUGH WESTERN OHIO WITH AN AREA OF
RAIN JUST AHEAD OF IT. NW WINDS WERE NOW BLOWING ACROSS MUCH OF THE
AREA WITH SOME GUSTS IN THE 25 TO 30 MPH RANGE. BEHIND THE
WAVE...PRECIP HAS WENT TO MORE OF A FLURRY/DRIZZLE SETUP AS ICE
PRODUCTION AND DEEPER LIFT APPEARS TO HAVE DEPARTED FOR THE MOMENT.
THIS WILL BE SHORT LIVED AS NEXT WAVE WAS RIGHT ON ITS HEELS
CURRENTLY WRAPPING UP OVER EAST IOWA/NW ILLINOIS BRINGS IN COLDER
LOW LEVEL TEMPS AND TRANSITION TO ALL SNOW FOR WHATEVER IS LEFT
OVER. LAKE EFFECT SNOW SHOWERS WILL MATERIALIZE LATE AFTERNOON INTO
THIS EVENING...BUT REMAIN WEAK AND DISORGANIZED AS MARGINAL DELTA
T`S PREVAIL. ENOUGH DEVELOPMENT SHOULD EXIST TO STILL WARRANT LIKELY
POPS DOWNWIND OF THE LAKE FOR THIS EVENING.

LAST WAVE...CURRENTLY ENTERING NORTHERN MINNESOTA...WILL RAPIDLY
DROP SOUTHEAST AND IMPACT THE REGION LATER TONIGHT INTO FRIDAY. BEST
LAKE EFFECT CHANCES WILL ARRIVE WITH THIS FEATURE AS 850 MB TEMPS
DROP TO -14 TO -16 C BY 12Z FRIDAY. A FAVORABLE FETCH DOWN THE WEST
PART OF THE LAKE CURVING EAST WOULD ALLOW FOR SOME STRONGER BAND
POTENTIAL. INVERSION HGTS WILL PEAK AROUND 7 KFT BRIEFLY BEHIND THE
WAVE BUT CO LOCATION WITH DGZ AND BEST LIFT WILL NEVER FULLY
COINCIDE. IN ADDITION...BANDS WILL LIKELY BE MOVING AROUND AS FLOW
VARIES BETWEEN 310 AND 330 DEGREES MUCH OF THE EVENT. ALL THESE
FACTORS SHOULD LIMIT AND THEN SLOWLY FALL. THIS SHOULD LIMIT
ACCUMULATIONS TO THE 1 TO 2 INCH RANGE.

IN TERMS OF TEMPERATURES...LOWS WILL DROP OFF INTO THE TEENS LATER
TONIGHT FOR MOST LOCATIONS WITH AREAS SHELTERED BY LAKE EFFECT
CLOUDS DROPPING IN THE LOWER TO MIDDLE 20S. ONLY A MINOR DIURNAL
SWING IN TEMPS IS EXPECTED ON FRIDAY.

&&

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 408 PM EST THU JAN 29 2015

COMPLEX AND VIGOROUS UPSTREAM INTERACTION BETWEEN MULTITUDE OF
SHORTWAVES BEGINNING TO CONVERGE INTERMODEL CONSENSUS. SURFACE RIDGE
OVHD FRIDAY EVENING WITH WEAK CLIPPER SYSTEM PUSHING SEWD THROUGH
NRN PLAINS. MOISTURE LACKING WITH BNDRY CONTG TO SLIDE SEWD THROUGH
GRTLKS SAT. FURTIVE SWD DIG OF HEIGHT FALL CENTROID TOWARD BAJA
CUTOFF SUPPORTING FARTHER SWD CYCLOGENESIS EMANATING OUT OF ARKLATEX
SUN AND INTO TN VALLEY SUN NIGHT. STILL STRONG OPEN/POSITIVE TILTED
7H WAVE WITH NRN FRINGE OF HFC PROVIDING 100-120M/12 HR HEIGHT
ADJUSTMENTS CARVES THROUGH SRN TIER CWA. HAVE MUTED POPS 00-06 UTC
SUNDAY WITH CONCERNS OF MODELS A BIT FAST IN OVERCOMING PRIOR
100-150MB LOW LEVEL CONDENSATION PRESSURE DEFICITS...BUT THEN RAMP
RAPIDLY BY 12 UTC. WHILE ENTIRE EVENT I280-285K ISENT UPGLIDE NOT
ASTOUNDING...THOUGH SYSTEM RELATIVE FLOW ESPECIALLY IN LWR LEVELS
ALONG WITH SIG MOISTURE FLUX CONVERGENCE INTO FAR SRN TIER CWA.
RAMPED POPS SUN...ESPECIALLY FAR SRN TIER ANTICIPATORY OF BEING ON
NRN FRINGE OF MARKED SNOWFALL GRADIENT. RICH BULK MOISTURE AROUND 3
G/KG 1000-850MB LAYER SUN ACRS SRN CWA...GRADUALLY LOWERS TO 2 G/KG
BY LATE AFTN/EVE AS SURFACE RESPONSE TIGHTENS SIGNIFICANTLY AND WELL
SOUTH OF CWA. BRIEF LES RESPONSE SUN NIGHT THOUGH QUICKLY ENDING
MONDAY AS PRIMARY SYSTEM FURTHER DEEPENS OFF MID ATL COAST...DRAWING
DRIER AIR/LOW SUBSIDENCE INVERSION THROUGH WRN GRLKS. WEAK CLIPPER
SYSTEM PSBL TUE/TUE NIGHT...FOLLOWED BY MEAGER LAKE RESPONSE INTO
MIDWEEK AS TROF SHARPENS THROUGH LWR GRTLKS.

&&

.UPDATE/AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED
AT 720 PM EST THU JAN 29 2015

SLOWLY DEEPENING LL CAA WING WILL YIELD CLOUD TOP ICE NUCLEATION
BY MID EVENING OUTSIDE BTR RADAR RTNS. PATCHY DZ W/SFC TEMPS NR
FREEZING MAY POSE A BRIEF PROBLEM EARLY THIS EVENING YET XPCD TO
GIVE WAY QUICKLY TO --SN/-SN.

GENERAL MVFR CONDS XPCD AT THE TERMINALS OVERNIGHT W/CONTD LL
VEERING STEERING MORE FOCUSED LAKE RESPONSE WWD W/TIME.
IMPROVEMENT TO VFR ANTICIPATED FRI AM.

&&

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

$$

SYNOPSIS...FISHER
SHORT TERM...FISHER
LONG TERM...MURPHY
AVIATION...T


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 300028
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
728 PM EST THU JAN 29 2015

.SYNOPSIS...
ISSUED AT 408 PM EST THU JAN 29 2015

COLDER AIR WILL MOVE IN ACROSS THE GREAT LAKES OVER THE NEXT 24
HOURS. LAKE EFFECT SNOW SHOWERS WILL IMPACT PORTIONS OF NORTHERN
INDIANA AND SOUTHWESTERN LOWER MICHIGAN INTO FRIDAY AFTERNOON
BEFORE DIMINISHING. LOWS TONIGHT WILL RANGE FROM THE MIDDLE 20S
WHERE LAKE EFFECT CLOUDS PERSIST...TO THE MIDDLE TEENS ELSEWHERE.
TEMPERATURES WILL RISE LITTLE ON FRIDAY WITH HIGHS IN THE LOWER TO
MIDDLE 20S.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 408 PM EST THU JAN 29 2015

FIRST OF 3 WAVES WAS NOW MOVING THROUGH WESTERN OHIO WITH AN AREA OF
RAIN JUST AHEAD OF IT. NW WINDS WERE NOW BLOWING ACROSS MUCH OF THE
AREA WITH SOME GUSTS IN THE 25 TO 30 MPH RANGE. BEHIND THE
WAVE...PRECIP HAS WENT TO MORE OF A FLURRY/DRIZZLE SETUP AS ICE
PRODUCTION AND DEEPER LIFT APPEARS TO HAVE DEPARTED FOR THE MOMENT.
THIS WILL BE SHORT LIVED AS NEXT WAVE WAS RIGHT ON ITS HEELS
CURRENTLY WRAPPING UP OVER EAST IOWA/NW ILLINOIS BRINGS IN COLDER
LOW LEVEL TEMPS AND TRANSITION TO ALL SNOW FOR WHATEVER IS LEFT
OVER. LAKE EFFECT SNOW SHOWERS WILL MATERIALIZE LATE AFTERNOON INTO
THIS EVENING...BUT REMAIN WEAK AND DISORGANIZED AS MARGINAL DELTA
T`S PREVAIL. ENOUGH DEVELOPMENT SHOULD EXIST TO STILL WARRANT LIKELY
POPS DOWNWIND OF THE LAKE FOR THIS EVENING.

LAST WAVE...CURRENTLY ENTERING NORTHERN MINNESOTA...WILL RAPIDLY
DROP SOUTHEAST AND IMPACT THE REGION LATER TONIGHT INTO FRIDAY. BEST
LAKE EFFECT CHANCES WILL ARRIVE WITH THIS FEATURE AS 850 MB TEMPS
DROP TO -14 TO -16 C BY 12Z FRIDAY. A FAVORABLE FETCH DOWN THE WEST
PART OF THE LAKE CURVING EAST WOULD ALLOW FOR SOME STRONGER BAND
POTENTIAL. INVERSION HGTS WILL PEAK AROUND 7 KFT BRIEFLY BEHIND THE
WAVE BUT CO LOCATION WITH DGZ AND BEST LIFT WILL NEVER FULLY
COINCIDE. IN ADDITION...BANDS WILL LIKELY BE MOVING AROUND AS FLOW
VARIES BETWEEN 310 AND 330 DEGREES MUCH OF THE EVENT. ALL THESE
FACTORS SHOULD LIMIT AND THEN SLOWLY FALL. THIS SHOULD LIMIT
ACCUMULATIONS TO THE 1 TO 2 INCH RANGE.

IN TERMS OF TEMPERATURES...LOWS WILL DROP OFF INTO THE TEENS LATER
TONIGHT FOR MOST LOCATIONS WITH AREAS SHELTERED BY LAKE EFFECT
CLOUDS DROPPING IN THE LOWER TO MIDDLE 20S. ONLY A MINOR DIURNAL
SWING IN TEMPS IS EXPECTED ON FRIDAY.

&&

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 408 PM EST THU JAN 29 2015

COMPLEX AND VIGOROUS UPSTREAM INTERACTION BETWEEN MULTITUDE OF
SHORTWAVES BEGINNING TO CONVERGE INTERMODEL CONSENSUS. SURFACE RIDGE
OVHD FRIDAY EVENING WITH WEAK CLIPPER SYSTEM PUSHING SEWD THROUGH
NRN PLAINS. MOISTURE LACKING WITH BNDRY CONTG TO SLIDE SEWD THROUGH
GRTLKS SAT. FURTIVE SWD DIG OF HEIGHT FALL CENTROID TOWARD BAJA
CUTOFF SUPPORTING FARTHER SWD CYCLOGENESIS EMANATING OUT OF ARKLATEX
SUN AND INTO TN VALLEY SUN NIGHT. STILL STRONG OPEN/POSITIVE TILTED
7H WAVE WITH NRN FRINGE OF HFC PROVIDING 100-120M/12 HR HEIGHT
ADJUSTMENTS CARVES THROUGH SRN TIER CWA. HAVE MUTED POPS 00-06 UTC
SUNDAY WITH CONCERNS OF MODELS A BIT FAST IN OVERCOMING PRIOR
100-150MB LOW LEVEL CONDENSATION PRESSURE DEFICITS...BUT THEN RAMP
RAPIDLY BY 12 UTC. WHILE ENTIRE EVENT I280-285K ISENT UPGLIDE NOT
ASTOUNDING...THOUGH SYSTEM RELATIVE FLOW ESPECIALLY IN LWR LEVELS
ALONG WITH SIG MOISTURE FLUX CONVERGENCE INTO FAR SRN TIER CWA.
RAMPED POPS SUN...ESPECIALLY FAR SRN TIER ANTICIPATORY OF BEING ON
NRN FRINGE OF MARKED SNOWFALL GRADIENT. RICH BULK MOISTURE AROUND 3
G/KG 1000-850MB LAYER SUN ACRS SRN CWA...GRADUALLY LOWERS TO 2 G/KG
BY LATE AFTN/EVE AS SURFACE RESPONSE TIGHTENS SIGNIFICANTLY AND WELL
SOUTH OF CWA. BRIEF LES RESPONSE SUN NIGHT THOUGH QUICKLY ENDING
MONDAY AS PRIMARY SYSTEM FURTHER DEEPENS OFF MID ATL COAST...DRAWING
DRIER AIR/LOW SUBSIDENCE INVERSION THROUGH WRN GRLKS. WEAK CLIPPER
SYSTEM PSBL TUE/TUE NIGHT...FOLLOWED BY MEAGER LAKE RESPONSE INTO
MIDWEEK AS TROF SHARPENS THROUGH LWR GRTLKS.

&&

.UPDATE/AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED
AT 720 PM EST THU JAN 29 2015

SLOWLY DEEPENING LL CAA WING WILL YIELD CLOUD TOP ICE NUCLEATION
BY MID EVENING OUTSIDE BTR RADAR RTNS. PATCHY DZ W/SFC TEMPS NR
FREEZING MAY POSE A BRIEF PROBLEM EARLY THIS EVENING YET XPCD TO
GIVE WAY QUICKLY TO --SN/-SN.

GENERAL MVFR CONDS XPCD AT THE TERMINALS OVERNIGHT W/CONTD LL
VEERING STEERING MORE FOCUSED LAKE RESPONSE WWD W/TIME.
IMPROVEMENT TO VFR ANTICIPATED FRI AM.

&&

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

$$

SYNOPSIS...FISHER
SHORT TERM...FISHER
LONG TERM...MURPHY
AVIATION...T


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 292118
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
418 PM EST THU JAN 29 2015

.SYNOPSIS...
ISSUED AT 408 PM EST THU JAN 29 2015

COLDER AIR WILL MOVE IN ACROSS THE GREAT LAKES OVER THE NEXT 24
HOURS. LAKE EFFECT SNOW SHOWERS WILL IMPACT PORTIONS OF NORTHERN
INDIANA AND SOUTHWESTERN LOWER MICHIGAN INTO FRIDAY AFTERNOON
BEFORE DIMINISHING. LOWS TONIGHT WILL RANGE FROM THE MIDDLE 20S
WHERE LAKE EFFECT CLOUDS PERSIST...TO THE MIDDLE TEENS ELSEWHERE.
TEMPERATURES WILL RISE LITTLE ON FRIDAY WITH HIGHS IN THE LOWER TO
MIDDLE 20S.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 408 PM EST THU JAN 29 2015

FIRST OF 3 WAVES WAS NOW MOVING THROUGH WESTERN OHIO WITH AN AREA OF
RAIN JUST AHEAD OF IT. NW WINDS WERE NOW BLOWING ACROSS MUCH OF THE
AREA WITH SOME GUSTS IN THE 25 TO 30 MPH RANGE. BEHIND THE
WAVE...PRECIP HAS WENT TO MORE OF A FLURRY/DRIZZLE SETUP AS ICE
PRODUCTION AND DEEPER LIFT APPEARS TO HAVE DEPARTED FOR THE MOMENT.
THIS WILL BE SHORT LIVED AS NEXT WAVE WAS RIGHT ON ITS HEELS
CURRENTLY WRAPPING UP OVER EAST IOWA/NW ILLINOIS BRINGS IN COLDER
LOW LEVEL TEMPS AND TRANSITION TO ALL SNOW FOR WHATEVER IS LEFT
OVER. LAKE EFFECT SNOW SHOWERS WILL MATERIALIZE LATE AFTERNOON INTO
THIS EVENING...BUT REMAIN WEAK AND DISORGANIZED AS MARGINAL DELTA
T`S PREVAIL. ENOUGH DEVELOPMENT SHOULD EXIST TO STILL WARRANT LIKELY
POPS DOWNWIND OF THE LAKE FOR THIS EVENING.

LAST WAVE...CURRENTLY ENTERING NORTHERN MINNESOTA...WILL RAPIDLY
DROP SOUTHEAST AND IMPACT THE REGION LATER TONIGHT INTO FRIDAY. BEST
LAKE EFFECT CHANCES WILL ARRIVE WITH THIS FEATURE AS 850 MB TEMPS
DROP TO -14 TO -16 C BY 12Z FRIDAY. A FAVORABLE FETCH DOWN THE WEST
PART OF THE LAKE CURVING EAST WOULD ALLOW FOR SOME STRONGER BAND
POTENTIAL. INVERSION HGTS WILL PEAK AROUND 7 KFT BRIEFLY BEHIND THE
WAVE BUT CO LOCATION WITH DGZ AND BEST LIFT WILL NEVER FULLY
COINCIDE. IN ADDITION...BANDS WILL LIKELY BE MOVING AROUND AS FLOW
VARIES BETWEEN 310 AND 330 DEGREES MUCH OF THE EVENT. ALL THESE
FACTORS SHOULD LIMIT AND THEN SLOWLY FALL. THIS SHOULD LIMIT
ACCUMULATIONS TO THE 1 TO 2 INCH RANGE.

IN TERMS OF TEMPERATURES...LOWS WILL DROP OFF INTO THE TEENS LATER
TONIGHT FOR MOST LOCATIONS WITH AREAS SHELTERED BY LAKE EFFECT
CLOUDS DROPPING IN THE LOWER TO MIDDLE 20S. ONLY A MINOR DIURNAL
SWING IN TEMPS IS EXPECTED ON FRIDAY.


&&

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 408 PM EST THU JAN 29 2015

COMPLEX AND VIGOROUS UPSTREAM INTERACTION BETWEEN MULTITUDE OF
SHORTWAVES BEGINNING TO CONVERGE INTERMODEL CONSENSUS. SURFACE RIDGE
OVHD FRIDAY EVENING WITH WEAK CLIPPER SYSTEM PUSHING SEWD THROUGH
NRN PLAINS. MOISTURE LACKING WITH BNDRY CONTG TO SLIDE SEWD THROUGH
GRTLKS SAT. FURTIVE SWD DIG OF HEIGHT FALL CENTROID TOWARD BAJA
CUTOFF SUPPORTING FARTHER SWD CYCLOGENESIS EMANATING OUT OF ARKLATEX
SUN AND INTO TN VALLEY SUN NIGHT. STILL STRONG OPEN/POSITIVE TILTED
7H WAVE WITH NRN FRINGE OF HFC PROVIDING 100-120M/12 HR HEIGHT
ADJUSTMENTS CARVES THROUGH SRN TIER CWA. HAVE MUTED POPS 00-06 UTC
SUNDAY WITH CONCERNS OF MODELS A BIT FAST IN OVERCOMING PRIOR
100-150MB LOW LEVEL CONDENSATION PRESSURE DEFICITS...BUT THEN RAMP
RAPIDLY BY 12 UTC. WHILE ENTIRE EVENT I280-285K ISENT UPGLIDE NOT
ASTOUNDING...THOUGH SYSTEM RELATIVE FLOW ESPECIALLY IN LWR LEVELS
ALONG WITH SIG MOISTURE FLUX CONVERGENCE INTO FAR SRN TIER CWA.
RAMPED POPS SUN...ESPECIALLY FAR SRN TIER ANTICIPATORY OF BEING ON
NRN FRINGE OF MARKED SNOWFALL GRADIENT. RICH BULK MOISTURE AROUND 3
G/KG 1000-850MB LAYER SUN ACRS SRN CWA...GRADUALLY LOWERS TO 2 G/KG
BY LATE AFTN/EVE AS SURFACE RESPONSE TIGHTENS SIGNIFICANTLY AND WELL
SOUTH OF CWA. BRIEF LES RESPONSE SUN NIGHT THOUGH QUICKLY ENDING
MONDAY AS PRIMARY SYSTEM FURTHER DEEPENS OFF MID ATL COAST...DRAWING
DRIER AIR/LOW SUBSIDENCE INVERSION THROUGH WRN GRLKS. WEAK CLIPPER
SYSTEM PSBL TUE/TUE NIGHT...FOLLOWED BY MEAGER LAKE RESPONSE INTO
MIDWEEK AS TROF SHARPENS THROUGH LWR GRTLKS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1143 AM EST THU JAN 29 2015

WINDS HAVE COME AROUND TO NW AT KSBN AND WILL REMAIN ON THE GUSTY
SIDE INTO THIS EVENING. EXPANSIVE STRATUS DECK WILL CONTINUE TO
MOVE IN WITH CIGS HOVERING IN THE 800 TO 1200 FT RANGE THROUGH
MUCH OF THE PERIOD. PERIODS OF SNOW SHOWERS WILL BECOME MORE
LIKELY WITH TIME AS WE MOVE INTO THE LATE AFTERNOON
HOURS...CONTINUING THROUGH THE NIGHT.

AT KFWA...WINDS SHOULD BECOME NW CLOSE TO OR JUST AFTER VALID TIME
OF TAFS WITH SOME LIGHT RAIN/SNOW INTO LATE AFTERNOON ALONG WITH
GUSTY WINDS. CIGS WILL REMAIN AROUND 1000 FT MUCH OF THE PERIOD AS
WELL.


&&

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

$$

SYNOPSIS...FISHER
SHORT TERM...FISHER
LONG TERM...MURPHY
AVIATION...FISHER


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 292118
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
418 PM EST THU JAN 29 2015

.SYNOPSIS...
ISSUED AT 408 PM EST THU JAN 29 2015

COLDER AIR WILL MOVE IN ACROSS THE GREAT LAKES OVER THE NEXT 24
HOURS. LAKE EFFECT SNOW SHOWERS WILL IMPACT PORTIONS OF NORTHERN
INDIANA AND SOUTHWESTERN LOWER MICHIGAN INTO FRIDAY AFTERNOON
BEFORE DIMINISHING. LOWS TONIGHT WILL RANGE FROM THE MIDDLE 20S
WHERE LAKE EFFECT CLOUDS PERSIST...TO THE MIDDLE TEENS ELSEWHERE.
TEMPERATURES WILL RISE LITTLE ON FRIDAY WITH HIGHS IN THE LOWER TO
MIDDLE 20S.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 408 PM EST THU JAN 29 2015

FIRST OF 3 WAVES WAS NOW MOVING THROUGH WESTERN OHIO WITH AN AREA OF
RAIN JUST AHEAD OF IT. NW WINDS WERE NOW BLOWING ACROSS MUCH OF THE
AREA WITH SOME GUSTS IN THE 25 TO 30 MPH RANGE. BEHIND THE
WAVE...PRECIP HAS WENT TO MORE OF A FLURRY/DRIZZLE SETUP AS ICE
PRODUCTION AND DEEPER LIFT APPEARS TO HAVE DEPARTED FOR THE MOMENT.
THIS WILL BE SHORT LIVED AS NEXT WAVE WAS RIGHT ON ITS HEELS
CURRENTLY WRAPPING UP OVER EAST IOWA/NW ILLINOIS BRINGS IN COLDER
LOW LEVEL TEMPS AND TRANSITION TO ALL SNOW FOR WHATEVER IS LEFT
OVER. LAKE EFFECT SNOW SHOWERS WILL MATERIALIZE LATE AFTERNOON INTO
THIS EVENING...BUT REMAIN WEAK AND DISORGANIZED AS MARGINAL DELTA
T`S PREVAIL. ENOUGH DEVELOPMENT SHOULD EXIST TO STILL WARRANT LIKELY
POPS DOWNWIND OF THE LAKE FOR THIS EVENING.

LAST WAVE...CURRENTLY ENTERING NORTHERN MINNESOTA...WILL RAPIDLY
DROP SOUTHEAST AND IMPACT THE REGION LATER TONIGHT INTO FRIDAY. BEST
LAKE EFFECT CHANCES WILL ARRIVE WITH THIS FEATURE AS 850 MB TEMPS
DROP TO -14 TO -16 C BY 12Z FRIDAY. A FAVORABLE FETCH DOWN THE WEST
PART OF THE LAKE CURVING EAST WOULD ALLOW FOR SOME STRONGER BAND
POTENTIAL. INVERSION HGTS WILL PEAK AROUND 7 KFT BRIEFLY BEHIND THE
WAVE BUT CO LOCATION WITH DGZ AND BEST LIFT WILL NEVER FULLY
COINCIDE. IN ADDITION...BANDS WILL LIKELY BE MOVING AROUND AS FLOW
VARIES BETWEEN 310 AND 330 DEGREES MUCH OF THE EVENT. ALL THESE
FACTORS SHOULD LIMIT AND THEN SLOWLY FALL. THIS SHOULD LIMIT
ACCUMULATIONS TO THE 1 TO 2 INCH RANGE.

IN TERMS OF TEMPERATURES...LOWS WILL DROP OFF INTO THE TEENS LATER
TONIGHT FOR MOST LOCATIONS WITH AREAS SHELTERED BY LAKE EFFECT
CLOUDS DROPPING IN THE LOWER TO MIDDLE 20S. ONLY A MINOR DIURNAL
SWING IN TEMPS IS EXPECTED ON FRIDAY.


&&

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 408 PM EST THU JAN 29 2015

COMPLEX AND VIGOROUS UPSTREAM INTERACTION BETWEEN MULTITUDE OF
SHORTWAVES BEGINNING TO CONVERGE INTERMODEL CONSENSUS. SURFACE RIDGE
OVHD FRIDAY EVENING WITH WEAK CLIPPER SYSTEM PUSHING SEWD THROUGH
NRN PLAINS. MOISTURE LACKING WITH BNDRY CONTG TO SLIDE SEWD THROUGH
GRTLKS SAT. FURTIVE SWD DIG OF HEIGHT FALL CENTROID TOWARD BAJA
CUTOFF SUPPORTING FARTHER SWD CYCLOGENESIS EMANATING OUT OF ARKLATEX
SUN AND INTO TN VALLEY SUN NIGHT. STILL STRONG OPEN/POSITIVE TILTED
7H WAVE WITH NRN FRINGE OF HFC PROVIDING 100-120M/12 HR HEIGHT
ADJUSTMENTS CARVES THROUGH SRN TIER CWA. HAVE MUTED POPS 00-06 UTC
SUNDAY WITH CONCERNS OF MODELS A BIT FAST IN OVERCOMING PRIOR
100-150MB LOW LEVEL CONDENSATION PRESSURE DEFICITS...BUT THEN RAMP
RAPIDLY BY 12 UTC. WHILE ENTIRE EVENT I280-285K ISENT UPGLIDE NOT
ASTOUNDING...THOUGH SYSTEM RELATIVE FLOW ESPECIALLY IN LWR LEVELS
ALONG WITH SIG MOISTURE FLUX CONVERGENCE INTO FAR SRN TIER CWA.
RAMPED POPS SUN...ESPECIALLY FAR SRN TIER ANTICIPATORY OF BEING ON
NRN FRINGE OF MARKED SNOWFALL GRADIENT. RICH BULK MOISTURE AROUND 3
G/KG 1000-850MB LAYER SUN ACRS SRN CWA...GRADUALLY LOWERS TO 2 G/KG
BY LATE AFTN/EVE AS SURFACE RESPONSE TIGHTENS SIGNIFICANTLY AND WELL
SOUTH OF CWA. BRIEF LES RESPONSE SUN NIGHT THOUGH QUICKLY ENDING
MONDAY AS PRIMARY SYSTEM FURTHER DEEPENS OFF MID ATL COAST...DRAWING
DRIER AIR/LOW SUBSIDENCE INVERSION THROUGH WRN GRLKS. WEAK CLIPPER
SYSTEM PSBL TUE/TUE NIGHT...FOLLOWED BY MEAGER LAKE RESPONSE INTO
MIDWEEK AS TROF SHARPENS THROUGH LWR GRTLKS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1143 AM EST THU JAN 29 2015

WINDS HAVE COME AROUND TO NW AT KSBN AND WILL REMAIN ON THE GUSTY
SIDE INTO THIS EVENING. EXPANSIVE STRATUS DECK WILL CONTINUE TO
MOVE IN WITH CIGS HOVERING IN THE 800 TO 1200 FT RANGE THROUGH
MUCH OF THE PERIOD. PERIODS OF SNOW SHOWERS WILL BECOME MORE
LIKELY WITH TIME AS WE MOVE INTO THE LATE AFTERNOON
HOURS...CONTINUING THROUGH THE NIGHT.

AT KFWA...WINDS SHOULD BECOME NW CLOSE TO OR JUST AFTER VALID TIME
OF TAFS WITH SOME LIGHT RAIN/SNOW INTO LATE AFTERNOON ALONG WITH
GUSTY WINDS. CIGS WILL REMAIN AROUND 1000 FT MUCH OF THE PERIOD AS
WELL.


&&

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

$$

SYNOPSIS...FISHER
SHORT TERM...FISHER
LONG TERM...MURPHY
AVIATION...FISHER


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 291700
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1200 PM EST THU JAN 29 2015

.SYNOPSIS...
ISSUED AT 1159 AM EST THU JAN 29 2015

A SERIES OF UPPER LEVEL DISTURBANCES WILL TRACK ACROSS THE REGION
TODAY. LIGHT RAIN WILL MIX WITH AND THEN CHANGE TO ALL SNOW BY
LATE AFTERNOON AS COLDER AIR ARRIVES. A DUSTING OF SNOW IS
POSSIBLE IN A FEW SPOTS. EVEN COLDER AIR WILL FILTER INTO THE
REGION TONIGHT BEHIND A FRONTAL BOUNDARY. THIS WILL PROVIDE THE
POTENTIAL OF LIGHT SNOW ACCUMULATIONS WITH LAKE EFFECT SNOW
SHOWERS TONIGHT INTO EARLY FRIDAY ACROSS PORTIONS OF SOUTHWESTERN
LOWER MICHIGAN AND NORTHWESTERN INDIANA. STEADY OR SLOWLY FALLING
TEMPERATURES IN THE LOW TO MID 30S ARE EXPECTED THE REST OF THE
DAY. LOW TEMPERATURES TONIGHT WILL RANGE FROM THE MID TEENS TO
LOWER 20S.

&&

.UPDATE...
ISSUED AT 1143 AM EST THU JAN 29 2015

2 WAVES BEING WATCHED INTO THE AFTERNOON HOURS. FIRST WAS MOVING
ACROSS NORTHERN INDIANA WITH RAIN SHOWERS AHEAD OF IT AND A
MIXTURE OF RAIN OR SNOW SHOWERS BEHIND IT. SECOND STRONGER WAVE
WILL SWEEP ACROSS THE AREA MID AFTERNOON AND BRING A QUICK BURST
OF LGT SNOW TO MANY AREAS. LITTLE OR NO ACCUMULATIONS ARE
EXPECTED...BUT WITH FALLING TEMPERATURES SOME SLICK SPOTS MAY
REFORM ON UNTREATED ROADS.

DID INCREASE POPS THIS AFTERNOON AS SEVERAL HIGH RES MODELS
SUGGEST BIT MORE COVERAGE TO PRECIP THAN PREVIOUSLY DEPICTED WITH
UPSTREAM OBS AND RADAR DATA GIVING SOME CREDENCE TO THIS. BEHIND
THE LOW GUSTY WINDS WILL MOVE IN WITH STRONGEST GUSTS WITHIN THE
FIRST FEW HOURS OF THE SHIFT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 421 AM EST THU JAN 29 2015

FORECAST CONCERN FOR THE SHORT TERM WILL CONTINUE TO CENTER ON
FREEZING RAIN CHANCES THIS MORNING...FOLLOWED BY POTENTIAL OF
CONTINUED LIGHT PRECIPITATION THROUGH THE DAY AND LAKE EFFECT SNOW
TONIGHT.

PRIMARY FORCING MECHANISM THROUGH MUCH OF THE OVERNIGHT HOURS HAS
BEEN A RELATIVELY NARROW ZONE OF MODERATE TO STRONG LOW/MID LEVEL
MOISTURE CONVERGENCE. THIS AXIS IS SHIFTING ACROSS EXTREME
NORTHEAST INDIANA AND SOUTH CENTRAL LOWER MICHIGAN AS OF 09Z. A
LIGHT GLAZE OF ICE ACCUMULATION WAS RECEIVED AT WFO IWX THIS MORNING
WITH THIS AXIS OF PRECIP. CURRENTLY EXPECTING THE BIGGEST CONCERNS
WILL PERSIST ACROSS EXTREME NORTHEAST INDIANA...FAR NORTHWEST
OHIO...AND SOUTH CENTRAL LOWER MICHIGAN THIS MORNING WHERE NEAR SFC
WARM ADVECTION IS WEAKER...AND NOT ABLE TO FULLY OFFSET EVAPORATIVE
COOLING EFFECTS. UP TO 0.05 INCHES OF ICE ACCUMULATION IS POSSIBLE
ACROSS ESPECIALLY NORTHEAST PORTIONS OF THE FREEZING RAIN ADVISORY
AREA. AFOREMENTIONED AXIS OF LOW/MID LEVEL MOISTURE CONVERGENCE
SHOULD BE FAIRLY PROGRESSIVE THROUGH NORTHWEST OHIO THROUGH 14Z
WHICH SHOULD MARK AN END TO ANY ADDITIONAL ICE ACCUMULATION. ONLY
WILDCARD FOR THIS FORECAST IS THE POTENTIAL OF UPSTREAM PV ANOMALY
ACROSS MID MS RIVER VALLEY TO IMPINGE ON THIS AXIS OF STRONGER
MOISTURE CONVERGENCE FORCING ACROSS NORTHWEST OHIO...WHICH COULD
YIELD AN INCREASE IN PRECIP COVERAGE/INTENSITY...ESPECIALLY
CONSIDERING THE APPROACH OF A PLUME OF VERY STEEP MID LEVEL LAPSE
RATES. FOR THIS REASON...HAVE CONTINUED TO HOLD THE EASTERN FREEZING
RAIN ADVISORY SEGMENT IN EFFECT UNTIL 10 AM EST...ALTHOUGH WILL
LIKELY BE ABLE TO CLEAR AT LEAST NORTHEAST INDIANA COUNTIES OVER THE
NEXT FEW HOURS. DID REMOVE A ST. JOSEPH INDIANA/WELLS/ADAMS COUNTY
FROM THE ADVISORY WITH SFC TEMPS HAVING RISEN ABOVE FREEZING.

FOR THE REMAINDER OF THE DAY...GUIDANCE STILL SUGGESTS POTENTIAL OF
PRECIP REDEVELOPING IN WEAK DEFORMATION/FGEN AXIS ACROSS NORTHWEST
PORTIONS OF THE AREA LATER THIS MORNING...AND SHIFTING ACROSS THE
REMAINDER OF THE AREA THIS AFTERNOON. IT DOES APPEAR AS THROUGH
LOCAL AREA MAY BE SITUATED BETWEEN THE MORE PRONOUNCED MID/UPPER
LEVEL WAVES THROUGH MOST OF THE AFTERNOON...LENDING TO SOME QUESTION
AS TO EXTENT OF MEASURABLE PRECIP IN THIS WEAK DEFORMATION AXIS.
HAVE MADE SOME SLIGHT DOWNWARD ADJUSTMENTS TO POPS BUT HAVE KEPT
GENERAL IDEA OF PREVIOUS FORECAST INTACT. THERMAL PROFILES SHOULD
SUPPORT MAINLY LIQUID FROM MID TO LATE MORNING ACROSS MOST OF THE
FORECAST AREA...WITH POSSIBLE EXCEPTION ACROSS THE FAR
NORTH/NORTHWEST WHERE SOME LIGHT SNOW/SLEET MAY MIX IN. SFC LOW
PRESSURE REACHING FAR SOUTHERN LAKE HURON THIS AFTERNOON WILL ALLOW
FOR ONSET OF MORE SIGNIFICANT COLD ADVECTION ACROSS ESPECIALLY
WESTERN/NORTHERN LOCATIONS WHERE A BRIEF PERIOD OF MAINLY LIGHT SNOW
IS POSSIBLE ON WESTERN PERIPHERY OF LIGHT DEFORMATION PRECIP.
MARGINAL THERMO PROFILES/LOW LEVEL WET BULBS SUGGEST LITTLE OR NO
SNOW ACCUMULATION HOWEVER. PRESSURE RISE BUBBLE WORKING ACROSS
SOUTHERN IOWA IS EXPECTED TO ENTER THE AREA THIS AFTERNOON...WHICH
SHOULD YIELD SOME WEST NORTHWEST GUSTS TO 20 TO 30 MPH ACCOMPANYING
THE LOW LEVEL CAA.

FOR TONIGHT...LAKE EFFECT/ENHANCED SNOW SHOWERS SHOULD DEVELOP EARLY
THIS EVENING AS WEAK SYNOPTIC UPPER WAVE TRACKS ACROSS THE SOUTHERN
GREAT LAKES. A MORE VIGOROUS WAVE DROPPING OUT OF SOUTH CENTRAL
CANADA WILL BRING MORE PRONOUNCED LOW LEVEL CAA AND INCREASING LAKE
EFFECT CHANCES DURING THE OVERNIGHT HOURS. RELATIVELY DRY MID LEVELS
AND SHALLOW INSTABILITY PROFILES CONTINUE TO SUGGEST MINOR SNOW
ACCUMS OF AN INCH OR TWO POSSIBLE FOR NORTHWEST FETCH LAKE EFFECT
AREAS.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 421 AM EST THU JAN 29 2015

LAKE EFFECT SNOW WILL GRADUALLY WIND DOWN DURING THE DAY FRIDAY.
INCREASING SUBSIDENCE/LOWERING INVERSION...BACKING WINDS...AND DRY
AIR ENTRAINMENT WILL TAKE AN INCREASING TOLL ON LAKE INDUCED
CONVECTION. ACCUMULATING SNOW WILL PROBABLY END BY MIDDAY WITH JUST
SOME RESIDUAL FLURRIES POSSIBLE ACROSS BERRIEN AND CASS COUNTIES
DURING THE AFTERNOON AS LOW LEVEL WINDS BACK TO A MORE WESTERLY
DIRECTION. HIGH TEMPS WILL BE ON THE COOL SIDE WITH THERMAL TROUGH
STILL IN PLACE BUT NOTHING OUT OF THE ORDINARY FOR LATE JANUARY.
EXPECT HIGHS GENERALLY IN THE MID 20S. W/SW LOW LEVEL FLOW DEVELOPS
BY FRIDAY NIGHT AND SATURDAY...ADVECTING SLIGHTLY WARMER AIR INTO
THE REGION AHEAD OF NEXT APPROACHING TROUGH. RAISED HIGHS A BIT TO
BE MORE IN LINE WITH LATEST MOS GUIDANCE. SHOULD MAKE A RUN AT LOWER
30S IN MOST LOCATIONS AFTER OVERNIGHT LOWS IN THE MID TO UPPER TEENS.

ATTENTION THEN TURNS TO POTENTIAL SNOW ON SUNDAY. AS EXPECTED...
DETERMINISTIC MODELS HAVE STRUGGLED IMMENSELY WITH THE EVOLUTION OF
THIS SYSTEM. RUN TO RUN VARIABILITY AND INTERMODEL DISAGREEMENT HAS
BEEN VERY HIGH. THIS IS NOT SURPRISING GIVEN THE EVENT IS PREDICATED
ON A RATHER COMPLEX INTERACTION BETWEEN MULTIPLE JET STREAKS AND
SHORTWAVES THAT HAVE NOT EVEN DEVELOPED YET. GFS ENSEMBLE MEMBERS
STILL SHOW A HIGH DEGREE OF SPREAD AND CONFIDENCE REMAINS VERY LOW.
00Z OPERATIONAL GFS TRENDED A BIT FURTHER NORTH BUT STILL KEEPS BULK
OF THE PRECIP SOUTH OF OUR CWA. LATEST GEM AND NAM EXTRAPOLATION
SUGGEST A STRONGER AND FURTHER NORTH SOLUTION WHILE THE ECMWF
REMAINS THE MOST SUBDUED. WILL LARGELY STAY THE COURSE WITH THIS
FORECAST PACKAGE. STILL MAINTAIN A BETTER THAN 50/50 SHOT OF
MEASURABLE SNOW BASED ON STRENGTH AND PLACEMENT OF UPPER LEVEL JET
SEEN IN ALL OF THE LATEST DETERMINISTIC MODELS...ESPECIALLY THE
FURTHER SOUTH YOU GO. CONFIDENCE IN EXACT AMOUNTS AND LOCATION
REMAIN VERY LOW HOWEVER. STAY TUNED TO THE LATEST FORECASTS OVER THE
NEXT DAY OR TWO AS THE SOLUTION SPACE SHOULD GRADUALLY NARROW.

MUCH COLDER AIR STILL EXPECTED EARLY NEXT WEEK AS 850MB TEMPS DROP
TO AROUND -20C. THIS SHOULD KEEP MONDAY`S HIGHS IN THE TEENS WITH
LOWS SUNDAY AND MONDAY NIGHT IN THE SINGLE DIGITS. BRIEF WARM UP
SEEN ON TUESDAY IN WAA REGIME AHEAD OF ANOTHER CLIPPER SYSTEM BUT
ANOTHER...POSSIBLY COLDER...ARCTIC SURGE IS POSSIBLE FOR THE MIDDLE
AND END OF NEXT WEEK. VERY HIGH AMPLITUDE RIDGE IS SHOWN TO DEVELOP
OVER WESTERN NOAM WITH PERSISTENT TROUGHING OVER EASTERN CANADA
YIELDING VERY COLD N/NW FLOW FOR THE GREAT LAKES.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1143 AM EST THU JAN 29 2015

WINDS HAVE COME AROUND TO NW AT KSBN AND WILL REMAIN ON THE GUSTY
SIDE INTO THIS EVENING. EXPANSIVE STRATUS DECK WILL CONTINUE TO
MOVE IN WITH CIGS HOVERING IN THE 800 TO 1200 FT RANGE THROUGH
MUCH OF THE PERIOD. PERIODS OF SNOW SHOWERS WILL BECOME MORE
LIKELY WITH TIME AS WE MOVE INTO THE LATE AFTERNOON
HOURS...CONTINUING THROUGH THE NIGHT.

AT KFWA...WINDS SHOULD BECOME NW CLOSE TO OR JUST AFTER VALID TIME
OF TAFS WITH SOME LIGHT RAIN/SNOW INTO LATE AFTERNOON ALONG WITH
GUSTY WINDS. CIGS WILL REMAIN AROUND 1000 FT MUCH OF THE PERIOD AS
WELL.

&&

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

$$

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


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 291700
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1200 PM EST THU JAN 29 2015

.SYNOPSIS...
ISSUED AT 1159 AM EST THU JAN 29 2015

A SERIES OF UPPER LEVEL DISTURBANCES WILL TRACK ACROSS THE REGION
TODAY. LIGHT RAIN WILL MIX WITH AND THEN CHANGE TO ALL SNOW BY
LATE AFTERNOON AS COLDER AIR ARRIVES. A DUSTING OF SNOW IS
POSSIBLE IN A FEW SPOTS. EVEN COLDER AIR WILL FILTER INTO THE
REGION TONIGHT BEHIND A FRONTAL BOUNDARY. THIS WILL PROVIDE THE
POTENTIAL OF LIGHT SNOW ACCUMULATIONS WITH LAKE EFFECT SNOW
SHOWERS TONIGHT INTO EARLY FRIDAY ACROSS PORTIONS OF SOUTHWESTERN
LOWER MICHIGAN AND NORTHWESTERN INDIANA. STEADY OR SLOWLY FALLING
TEMPERATURES IN THE LOW TO MID 30S ARE EXPECTED THE REST OF THE
DAY. LOW TEMPERATURES TONIGHT WILL RANGE FROM THE MID TEENS TO
LOWER 20S.

&&

.UPDATE...
ISSUED AT 1143 AM EST THU JAN 29 2015

2 WAVES BEING WATCHED INTO THE AFTERNOON HOURS. FIRST WAS MOVING
ACROSS NORTHERN INDIANA WITH RAIN SHOWERS AHEAD OF IT AND A
MIXTURE OF RAIN OR SNOW SHOWERS BEHIND IT. SECOND STRONGER WAVE
WILL SWEEP ACROSS THE AREA MID AFTERNOON AND BRING A QUICK BURST
OF LGT SNOW TO MANY AREAS. LITTLE OR NO ACCUMULATIONS ARE
EXPECTED...BUT WITH FALLING TEMPERATURES SOME SLICK SPOTS MAY
REFORM ON UNTREATED ROADS.

DID INCREASE POPS THIS AFTERNOON AS SEVERAL HIGH RES MODELS
SUGGEST BIT MORE COVERAGE TO PRECIP THAN PREVIOUSLY DEPICTED WITH
UPSTREAM OBS AND RADAR DATA GIVING SOME CREDENCE TO THIS. BEHIND
THE LOW GUSTY WINDS WILL MOVE IN WITH STRONGEST GUSTS WITHIN THE
FIRST FEW HOURS OF THE SHIFT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 421 AM EST THU JAN 29 2015

FORECAST CONCERN FOR THE SHORT TERM WILL CONTINUE TO CENTER ON
FREEZING RAIN CHANCES THIS MORNING...FOLLOWED BY POTENTIAL OF
CONTINUED LIGHT PRECIPITATION THROUGH THE DAY AND LAKE EFFECT SNOW
TONIGHT.

PRIMARY FORCING MECHANISM THROUGH MUCH OF THE OVERNIGHT HOURS HAS
BEEN A RELATIVELY NARROW ZONE OF MODERATE TO STRONG LOW/MID LEVEL
MOISTURE CONVERGENCE. THIS AXIS IS SHIFTING ACROSS EXTREME
NORTHEAST INDIANA AND SOUTH CENTRAL LOWER MICHIGAN AS OF 09Z. A
LIGHT GLAZE OF ICE ACCUMULATION WAS RECEIVED AT WFO IWX THIS MORNING
WITH THIS AXIS OF PRECIP. CURRENTLY EXPECTING THE BIGGEST CONCERNS
WILL PERSIST ACROSS EXTREME NORTHEAST INDIANA...FAR NORTHWEST
OHIO...AND SOUTH CENTRAL LOWER MICHIGAN THIS MORNING WHERE NEAR SFC
WARM ADVECTION IS WEAKER...AND NOT ABLE TO FULLY OFFSET EVAPORATIVE
COOLING EFFECTS. UP TO 0.05 INCHES OF ICE ACCUMULATION IS POSSIBLE
ACROSS ESPECIALLY NORTHEAST PORTIONS OF THE FREEZING RAIN ADVISORY
AREA. AFOREMENTIONED AXIS OF LOW/MID LEVEL MOISTURE CONVERGENCE
SHOULD BE FAIRLY PROGRESSIVE THROUGH NORTHWEST OHIO THROUGH 14Z
WHICH SHOULD MARK AN END TO ANY ADDITIONAL ICE ACCUMULATION. ONLY
WILDCARD FOR THIS FORECAST IS THE POTENTIAL OF UPSTREAM PV ANOMALY
ACROSS MID MS RIVER VALLEY TO IMPINGE ON THIS AXIS OF STRONGER
MOISTURE CONVERGENCE FORCING ACROSS NORTHWEST OHIO...WHICH COULD
YIELD AN INCREASE IN PRECIP COVERAGE/INTENSITY...ESPECIALLY
CONSIDERING THE APPROACH OF A PLUME OF VERY STEEP MID LEVEL LAPSE
RATES. FOR THIS REASON...HAVE CONTINUED TO HOLD THE EASTERN FREEZING
RAIN ADVISORY SEGMENT IN EFFECT UNTIL 10 AM EST...ALTHOUGH WILL
LIKELY BE ABLE TO CLEAR AT LEAST NORTHEAST INDIANA COUNTIES OVER THE
NEXT FEW HOURS. DID REMOVE A ST. JOSEPH INDIANA/WELLS/ADAMS COUNTY
FROM THE ADVISORY WITH SFC TEMPS HAVING RISEN ABOVE FREEZING.

FOR THE REMAINDER OF THE DAY...GUIDANCE STILL SUGGESTS POTENTIAL OF
PRECIP REDEVELOPING IN WEAK DEFORMATION/FGEN AXIS ACROSS NORTHWEST
PORTIONS OF THE AREA LATER THIS MORNING...AND SHIFTING ACROSS THE
REMAINDER OF THE AREA THIS AFTERNOON. IT DOES APPEAR AS THROUGH
LOCAL AREA MAY BE SITUATED BETWEEN THE MORE PRONOUNCED MID/UPPER
LEVEL WAVES THROUGH MOST OF THE AFTERNOON...LENDING TO SOME QUESTION
AS TO EXTENT OF MEASURABLE PRECIP IN THIS WEAK DEFORMATION AXIS.
HAVE MADE SOME SLIGHT DOWNWARD ADJUSTMENTS TO POPS BUT HAVE KEPT
GENERAL IDEA OF PREVIOUS FORECAST INTACT. THERMAL PROFILES SHOULD
SUPPORT MAINLY LIQUID FROM MID TO LATE MORNING ACROSS MOST OF THE
FORECAST AREA...WITH POSSIBLE EXCEPTION ACROSS THE FAR
NORTH/NORTHWEST WHERE SOME LIGHT SNOW/SLEET MAY MIX IN. SFC LOW
PRESSURE REACHING FAR SOUTHERN LAKE HURON THIS AFTERNOON WILL ALLOW
FOR ONSET OF MORE SIGNIFICANT COLD ADVECTION ACROSS ESPECIALLY
WESTERN/NORTHERN LOCATIONS WHERE A BRIEF PERIOD OF MAINLY LIGHT SNOW
IS POSSIBLE ON WESTERN PERIPHERY OF LIGHT DEFORMATION PRECIP.
MARGINAL THERMO PROFILES/LOW LEVEL WET BULBS SUGGEST LITTLE OR NO
SNOW ACCUMULATION HOWEVER. PRESSURE RISE BUBBLE WORKING ACROSS
SOUTHERN IOWA IS EXPECTED TO ENTER THE AREA THIS AFTERNOON...WHICH
SHOULD YIELD SOME WEST NORTHWEST GUSTS TO 20 TO 30 MPH ACCOMPANYING
THE LOW LEVEL CAA.

FOR TONIGHT...LAKE EFFECT/ENHANCED SNOW SHOWERS SHOULD DEVELOP EARLY
THIS EVENING AS WEAK SYNOPTIC UPPER WAVE TRACKS ACROSS THE SOUTHERN
GREAT LAKES. A MORE VIGOROUS WAVE DROPPING OUT OF SOUTH CENTRAL
CANADA WILL BRING MORE PRONOUNCED LOW LEVEL CAA AND INCREASING LAKE
EFFECT CHANCES DURING THE OVERNIGHT HOURS. RELATIVELY DRY MID LEVELS
AND SHALLOW INSTABILITY PROFILES CONTINUE TO SUGGEST MINOR SNOW
ACCUMS OF AN INCH OR TWO POSSIBLE FOR NORTHWEST FETCH LAKE EFFECT
AREAS.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 421 AM EST THU JAN 29 2015

LAKE EFFECT SNOW WILL GRADUALLY WIND DOWN DURING THE DAY FRIDAY.
INCREASING SUBSIDENCE/LOWERING INVERSION...BACKING WINDS...AND DRY
AIR ENTRAINMENT WILL TAKE AN INCREASING TOLL ON LAKE INDUCED
CONVECTION. ACCUMULATING SNOW WILL PROBABLY END BY MIDDAY WITH JUST
SOME RESIDUAL FLURRIES POSSIBLE ACROSS BERRIEN AND CASS COUNTIES
DURING THE AFTERNOON AS LOW LEVEL WINDS BACK TO A MORE WESTERLY
DIRECTION. HIGH TEMPS WILL BE ON THE COOL SIDE WITH THERMAL TROUGH
STILL IN PLACE BUT NOTHING OUT OF THE ORDINARY FOR LATE JANUARY.
EXPECT HIGHS GENERALLY IN THE MID 20S. W/SW LOW LEVEL FLOW DEVELOPS
BY FRIDAY NIGHT AND SATURDAY...ADVECTING SLIGHTLY WARMER AIR INTO
THE REGION AHEAD OF NEXT APPROACHING TROUGH. RAISED HIGHS A BIT TO
BE MORE IN LINE WITH LATEST MOS GUIDANCE. SHOULD MAKE A RUN AT LOWER
30S IN MOST LOCATIONS AFTER OVERNIGHT LOWS IN THE MID TO UPPER TEENS.

ATTENTION THEN TURNS TO POTENTIAL SNOW ON SUNDAY. AS EXPECTED...
DETERMINISTIC MODELS HAVE STRUGGLED IMMENSELY WITH THE EVOLUTION OF
THIS SYSTEM. RUN TO RUN VARIABILITY AND INTERMODEL DISAGREEMENT HAS
BEEN VERY HIGH. THIS IS NOT SURPRISING GIVEN THE EVENT IS PREDICATED
ON A RATHER COMPLEX INTERACTION BETWEEN MULTIPLE JET STREAKS AND
SHORTWAVES THAT HAVE NOT EVEN DEVELOPED YET. GFS ENSEMBLE MEMBERS
STILL SHOW A HIGH DEGREE OF SPREAD AND CONFIDENCE REMAINS VERY LOW.
00Z OPERATIONAL GFS TRENDED A BIT FURTHER NORTH BUT STILL KEEPS BULK
OF THE PRECIP SOUTH OF OUR CWA. LATEST GEM AND NAM EXTRAPOLATION
SUGGEST A STRONGER AND FURTHER NORTH SOLUTION WHILE THE ECMWF
REMAINS THE MOST SUBDUED. WILL LARGELY STAY THE COURSE WITH THIS
FORECAST PACKAGE. STILL MAINTAIN A BETTER THAN 50/50 SHOT OF
MEASURABLE SNOW BASED ON STRENGTH AND PLACEMENT OF UPPER LEVEL JET
SEEN IN ALL OF THE LATEST DETERMINISTIC MODELS...ESPECIALLY THE
FURTHER SOUTH YOU GO. CONFIDENCE IN EXACT AMOUNTS AND LOCATION
REMAIN VERY LOW HOWEVER. STAY TUNED TO THE LATEST FORECASTS OVER THE
NEXT DAY OR TWO AS THE SOLUTION SPACE SHOULD GRADUALLY NARROW.

MUCH COLDER AIR STILL EXPECTED EARLY NEXT WEEK AS 850MB TEMPS DROP
TO AROUND -20C. THIS SHOULD KEEP MONDAY`S HIGHS IN THE TEENS WITH
LOWS SUNDAY AND MONDAY NIGHT IN THE SINGLE DIGITS. BRIEF WARM UP
SEEN ON TUESDAY IN WAA REGIME AHEAD OF ANOTHER CLIPPER SYSTEM BUT
ANOTHER...POSSIBLY COLDER...ARCTIC SURGE IS POSSIBLE FOR THE MIDDLE
AND END OF NEXT WEEK. VERY HIGH AMPLITUDE RIDGE IS SHOWN TO DEVELOP
OVER WESTERN NOAM WITH PERSISTENT TROUGHING OVER EASTERN CANADA
YIELDING VERY COLD N/NW FLOW FOR THE GREAT LAKES.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1143 AM EST THU JAN 29 2015

WINDS HAVE COME AROUND TO NW AT KSBN AND WILL REMAIN ON THE GUSTY
SIDE INTO THIS EVENING. EXPANSIVE STRATUS DECK WILL CONTINUE TO
MOVE IN WITH CIGS HOVERING IN THE 800 TO 1200 FT RANGE THROUGH
MUCH OF THE PERIOD. PERIODS OF SNOW SHOWERS WILL BECOME MORE
LIKELY WITH TIME AS WE MOVE INTO THE LATE AFTERNOON
HOURS...CONTINUING THROUGH THE NIGHT.

AT KFWA...WINDS SHOULD BECOME NW CLOSE TO OR JUST AFTER VALID TIME
OF TAFS WITH SOME LIGHT RAIN/SNOW INTO LATE AFTERNOON ALONG WITH
GUSTY WINDS. CIGS WILL REMAIN AROUND 1000 FT MUCH OF THE PERIOD AS
WELL.

&&

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

$$

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


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 291210
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
710 AM EST THU JAN 29 2015

.SYNOPSIS...
ISSUED AT 421 AM EST THU JAN 29 2015

A SERIES OF UPPER LEVEL DISTURBANCES WILL TRACK ACROSS THE REGION
TODAY. AFTER A PERIOD OF LIGHT FREEZING RAIN THIS MORNING ACROSS
SOUTHERN LOWER MICHIGAN...NORTHEAST INDIANA...AND NORTHWEST
OHIO...A MIX OF LIGHT RAIN AND LIGHT SNOW IS THEN EXPECTED THIS
AFTERNOON WITH LITTLE OR NO SNOW ACCUMULATION. COLDER AIR WILL
FILTER INTO THE REGION LATER THIS AFTERNOON INTO TONIGHT BEHIND A
FRONTAL BOUNDARY. THIS WILL PROVIDE THE POTENTIAL OF LIGHT SNOW
ACCUMULATIONS WITH LAKE EFFECT SNOW SHOWERS TONIGHT INTO EARLY FRIDAY.
HIGH TEMPERATURES THIS AFTERNOON WILL RANGE FROM THE MID 30S TO
AROUND 40. LOW TEMPERATURES TONIGHT WILL RANGE FROM THE MID TEENS
TO LOWER 20S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 421 AM EST THU JAN 29 2015

FORECAST CONCERN FOR THE SHORT TERM WILL CONTINUE TO CENTER ON
FREEZING RAIN CHANCES THIS MORNING...FOLLOWED BY POTENTIAL OF
CONTINUED LIGHT PRECIPITATION THROUGH THE DAY AND LAKE EFFECT SNOW
TONIGHT.

PRIMARY FORCING MECHANISM THROUGH MUCH OF THE OVERNIGHT HOURS HAS
BEEN A RELATIVELY NARROW ZONE OF MODERATE TO STRONG LOW/MID LEVEL
MOISTURE CONVERGENCE. THIS AXIS IS SHIFTING ACROSS EXTREME
NORTHEAST INDIANA AND SOUTH CENTRAL LOWER MICHIGAN AS OF 09Z. A
LIGHT GLAZE OF ICE ACCUMULATION WAS RECEIVED AT WFO IWX THIS MORNING
WITH THIS AXIS OF PRECIP. CURRENTLY EXPECTING THE BIGGEST CONCERNS
WILL PERSIST ACROSS EXTREME NORTHEAST INDIANA...FAR NORTHWEST
OHIO...AND SOUTH CENTRAL LOWER MICHIGAN THIS MORNING WHERE NEAR SFC
WARM ADVECTION IS WEAKER...AND NOT ABLE TO FULLY OFFSET EVAPORATIVE
COOLING EFFECTS. UP TO 0.05 INCHES OF ICE ACCUMULATION IS POSSIBLE
ACROSS ESPECIALLY NORTHEAST PORTIONS OF THE FREEZING RAIN ADVISORY
AREA. AFOREMENTIONED AXIS OF LOW/MID LEVEL MOISTURE CONVERGENCE
SHOULD BE FAIRLY PROGRESSIVE THROUGH NORTHWEST OHIO THROUGH 14Z
WHICH SHOULD MARK AN END TO ANY ADDITIONAL ICE ACCUMULATION. ONLY
WILDCARD FOR THIS FORECAST IS THE POTENTIAL OF UPSTREAM PV ANOMALY
ACROSS MID MS RIVER VALLEY TO IMPINGE ON THIS AXIS OF STRONGER
MOISTURE CONVERGENCE FORCING ACROSS NORTHWEST OHIO...WHICH COULD
YIELD AN INCREASE IN PRECIP COVERAGE/INTENSITY...ESPECIALLY
CONSIDERING THE APPROACH OF A PLUME OF VERY STEEP MID LEVEL LAPSE
RATES. FOR THIS REASON...HAVE CONTINUED TO HOLD THE EASTERN FREEZING
RAIN ADVISORY SEGMENT IN EFFECT UNTIL 10 AM EST...ALTHOUGH WILL
LIKELY BE ABLE TO CLEAR AT LEAST NORTHEAST INDIANA COUNTIES OVER THE
NEXT FEW HOURS. DID REMOVE A ST. JOSEPH INDIANA/WELLS/ADAMS COUNTY
FROM THE ADVISORY WITH SFC TEMPS HAVING RISEN ABOVE FREEZING.

FOR THE REMAINDER OF THE DAY...GUIDANCE STILL SUGGESTS POTENTIAL OF
PRECIP REDEVELOPING IN WEAK DEFORMATION/FGEN AXIS ACROSS NORTHWEST
PORTIONS OF THE AREA LATER THIS MORNING...AND SHIFTING ACROSS THE
REMAINDER OF THE AREA THIS AFTERNOON. IT DOES APPEAR AS THROUGH
LOCAL AREA MAY BE SITUATED BETWEEN THE MORE PRONOUNCED MID/UPPER
LEVEL WAVES THROUGH MOST OF THE AFTERNOON...LENDING TO SOME QUESTION
AS TO EXTENT OF MEASURABLE PRECIP IN THIS WEAK DEFORMATION AXIS.
HAVE MADE SOME SLIGHT DOWNWARD ADJUSTMENTS TO POPS BUT HAVE KEPT
GENERAL IDEA OF PREVIOUS FORECAST INTACT. THERMAL PROFILES SHOULD
SUPPORT MAINLY LIQUID FROM MID TO LATE MORNING ACROSS MOST OF THE
FORECAST AREA...WITH POSSIBLE EXCEPTION ACROSS THE FAR
NORTH/NORTHWEST WHERE SOME LIGHT SNOW/SLEET MAY MIX IN. SFC LOW
PRESSURE REACHING FAR SOUTHERN LAKE HURON THIS AFTERNOON WILL ALLOW
FOR ONSET OF MORE SIGNIFICANT COLD ADVECTION ACROSS ESPECIALLY
WESTERN/NORTHERN LOCATIONS WHERE A BRIEF PERIOD OF MAINLY LIGHT SNOW
IS POSSIBLE ON WESTERN PERIPHERY OF LIGHT DEFORMATION PRECIP.
MARGINAL THERMO PROFILES/LOW LEVEL WET BULBS SUGGEST LITTLE OR NO
SNOW ACCUMULATION HOWEVER. PRESSURE RISE BUBBLE WORKING ACROSS
SOUTHERN IOWA IS EXPECTED TO ENTER THE AREA THIS AFTERNOON...WHICH
SHOULD YIELD SOME WEST NORTHWEST GUSTS TO 20 TO 30 MPH ACCOMPANYING
THE LOW LEVEL CAA.

FOR TONIGHT...LAKE EFFECT/ENHANCED SNOW SHOWERS SHOULD DEVELOP EARLY
THIS EVENING AS WEAK SYNOPTIC UPPER WAVE TRACKS ACROSS THE SOUTHERN
GREAT LAKES. A MORE VIGOROUS WAVE DROPPING OUT OF SOUTH CENTRAL
CANADA WILL BRING MORE PRONOUNCED LOW LEVEL CAA AND INCREASING LAKE
EFFECT CHANCES DURING THE OVERNIGHT HOURS. RELATIVELY DRY MID LEVELS
AND SHALLOW INSTABILITY PROFILES CONTINUE TO SUGGEST MINOR SNOW
ACCUMS OF AN INCH OR TWO POSSIBLE FOR NORTHWEST FETCH LAKE EFFECT
AREAS.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 421 AM EST THU JAN 29 2015

LAKE EFFECT SNOW WILL GRADUALLY WIND DOWN DURING THE DAY FRIDAY.
INCREASING SUBSIDENCE/LOWERING INVERSION...BACKING WINDS...AND DRY
AIR ENTRAINMENT WILL TAKE AN INCREASING TOLL ON LAKE INDUCED
CONVECTION. ACCUMULATING SNOW WILL PROBABLY END BY MIDDAY WITH JUST
SOME RESIDUAL FLURRIES POSSIBLE ACROSS BERRIEN AND CASS COUNTIES
DURING THE AFTERNOON AS LOW LEVEL WINDS BACK TO A MORE WESTERLY
DIRECTION. HIGH TEMPS WILL BE ON THE COOL SIDE WITH THERMAL TROUGH
STILL IN PLACE BUT NOTHING OUT OF THE ORDINARY FOR LATE JANUARY.
EXPECT HIGHS GENERALLY IN THE MID 20S. W/SW LOW LEVEL FLOW DEVELOPS
BY FRIDAY NIGHT AND SATURDAY...ADVECTING SLIGHTLY WARMER AIR INTO
THE REGION AHEAD OF NEXT APPROACHING TROUGH. RAISED HIGHS A BIT TO
BE MORE IN LINE WITH LATEST MOS GUIDANCE. SHOULD MAKE A RUN AT LOWER
30S IN MOST LOCATIONS AFTER OVERNIGHT LOWS IN THE MID TO UPPER TEENS.

ATTENTION THEN TURNS TO POTENTIAL SNOW ON SUNDAY. AS EXPECTED...
DETERMINISTIC MODELS HAVE STRUGGLED IMMENSELY WITH THE EVOLUTION OF
THIS SYSTEM. RUN TO RUN VARIABILITY AND INTERMODEL DISAGREEMENT HAS
BEEN VERY HIGH. THIS IS NOT SURPRISING GIVEN THE EVENT IS PREDICATED
ON A RATHER COMPLEX INTERACTION BETWEEN MULTIPLE JET STREAKS AND
SHORTWAVES THAT HAVE NOT EVEN DEVELOPED YET. GFS ENSEMBLE MEMBERS
STILL SHOW A HIGH DEGREE OF SPREAD AND CONFIDENCE REMAINS VERY LOW.
00Z OPERATIONAL GFS TRENDED A BIT FURTHER NORTH BUT STILL KEEPS BULK
OF THE PRECIP SOUTH OF OUR CWA. LATEST GEM AND NAM EXTRAPOLATION
SUGGEST A STRONGER AND FURTHER NORTH SOLUTION WHILE THE ECMWF
REMAINS THE MOST SUBDUED. WILL LARGELY STAY THE COURSE WITH THIS
FORECAST PACKAGE. STILL MAINTAIN A BETTER THAN 50/50 SHOT OF
MEASURABLE SNOW BASED ON STRENGTH AND PLACEMENT OF UPPER LEVEL JET
SEEN IN ALL OF THE LATEST DETERMINISTIC MODELS...ESPECIALLY THE
FURTHER SOUTH YOU GO. CONFIDENCE IN EXACT AMOUNTS AND LOCATION
REMAIN VERY LOW HOWEVER. STAY TUNED TO THE LATEST FORECASTS OVER THE
NEXT DAY OR TWO AS THE SOLUTION SPACE SHOULD GRADUALLY NARROW.

MUCH COLDER AIR STILL EXPECTED EARLY NEXT WEEK AS 850MB TEMPS DROP
TO AROUND -20C. THIS SHOULD KEEP MONDAY`S HIGHS IN THE TEENS WITH
LOWS SUNDAY AND MONDAY NIGHT IN THE SINGLE DIGITS. BRIEF WARM UP
SEEN ON TUESDAY IN WAA REGIME AHEAD OF ANOTHER CLIPPER SYSTEM BUT
ANOTHER...POSSIBLY COLDER...ARCTIC SURGE IS POSSIBLE FOR THE MIDDLE
AND END OF NEXT WEEK. VERY HIGH AMPLITUDE RIDGE IS SHOWN TO DEVELOP
OVER WESTERN NOAM WITH PERSISTENT TROUGHING OVER EASTERN CANADA
YIELDING VERY COLD N/NW FLOW FOR THE GREAT LAKES.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 658 AM EST THU JAN 29 2015

NO SUBSTANTIAL CHANGES MADE FROM PREVIOUS FORECAST FOR THE 12Z
TAFS. ZONE OF LOW/MID LEVEL MOISTURE CONVERGENCE HAS NOW EXITED
INTO NORTHWEST OHIO TAKING MOST OF THE FREEZING RAIN EAST OF THE
TERMINALS. LIGHT RAIN MAY REDEVELOP LATER THIS MORNING AS A FAIRLY
STRONG UPPER VORT MAX TRACKS INTO THE AREA FROM NORTHERN ILLINOIS.
WEAK DEFORMATION ZONE SHOULD ALLOW FOR RAIN/SNOW TO DEVELOP EARLY
THIS AFTERNOON...EVENTUALLY CHANGING TO PRIMARILY SNOW LATER THIS
AFTERNOON AS COLDER AIR ADVECTS SOUTHWARD. SFC LOW PRESSURE WILL
WORK ACROSS SOUTHERN LAKE HURON THIS AFTERNOON WHICH WILL DRAG A
FRONTAL BOUNDARY EASTWARD ACROSS THE AREA. CIGS ARE EXPECTED TO
DETERIORATE BY MID TO LATE MORNING AS LOW LEVEL REFLECTION
APPROACHES THE AREA...WITH LOWER END MVFR OR IFR CIGS PERSISTING
THROUGH MUCH OF THE DAY. LAKE EFFECT SNOW SHOWERS WILL DEVELOP
TONIGHT...WITH A PERIOD OF IFR VSBYS POSSIBLE AT KSBN LATE IN THE
PERIOD. NORTHWEST WINDS WILL DEVELOP BEHIND THE FRONT THIS
AFTERNOON...WITH GUSTS TO AROUND 25 KNOTS EXPECTED.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...FREEZING RAIN ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ081.

OH...FREEZING RAIN ADVISORY UNTIL 10 AM EST THIS MORNING FOR OHZ001-
     002-004-005-015-016-024-025.

LM...NONE.
&&

$$

SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...AGD
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 291210
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
710 AM EST THU JAN 29 2015

.SYNOPSIS...
ISSUED AT 421 AM EST THU JAN 29 2015

A SERIES OF UPPER LEVEL DISTURBANCES WILL TRACK ACROSS THE REGION
TODAY. AFTER A PERIOD OF LIGHT FREEZING RAIN THIS MORNING ACROSS
SOUTHERN LOWER MICHIGAN...NORTHEAST INDIANA...AND NORTHWEST
OHIO...A MIX OF LIGHT RAIN AND LIGHT SNOW IS THEN EXPECTED THIS
AFTERNOON WITH LITTLE OR NO SNOW ACCUMULATION. COLDER AIR WILL
FILTER INTO THE REGION LATER THIS AFTERNOON INTO TONIGHT BEHIND A
FRONTAL BOUNDARY. THIS WILL PROVIDE THE POTENTIAL OF LIGHT SNOW
ACCUMULATIONS WITH LAKE EFFECT SNOW SHOWERS TONIGHT INTO EARLY FRIDAY.
HIGH TEMPERATURES THIS AFTERNOON WILL RANGE FROM THE MID 30S TO
AROUND 40. LOW TEMPERATURES TONIGHT WILL RANGE FROM THE MID TEENS
TO LOWER 20S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 421 AM EST THU JAN 29 2015

FORECAST CONCERN FOR THE SHORT TERM WILL CONTINUE TO CENTER ON
FREEZING RAIN CHANCES THIS MORNING...FOLLOWED BY POTENTIAL OF
CONTINUED LIGHT PRECIPITATION THROUGH THE DAY AND LAKE EFFECT SNOW
TONIGHT.

PRIMARY FORCING MECHANISM THROUGH MUCH OF THE OVERNIGHT HOURS HAS
BEEN A RELATIVELY NARROW ZONE OF MODERATE TO STRONG LOW/MID LEVEL
MOISTURE CONVERGENCE. THIS AXIS IS SHIFTING ACROSS EXTREME
NORTHEAST INDIANA AND SOUTH CENTRAL LOWER MICHIGAN AS OF 09Z. A
LIGHT GLAZE OF ICE ACCUMULATION WAS RECEIVED AT WFO IWX THIS MORNING
WITH THIS AXIS OF PRECIP. CURRENTLY EXPECTING THE BIGGEST CONCERNS
WILL PERSIST ACROSS EXTREME NORTHEAST INDIANA...FAR NORTHWEST
OHIO...AND SOUTH CENTRAL LOWER MICHIGAN THIS MORNING WHERE NEAR SFC
WARM ADVECTION IS WEAKER...AND NOT ABLE TO FULLY OFFSET EVAPORATIVE
COOLING EFFECTS. UP TO 0.05 INCHES OF ICE ACCUMULATION IS POSSIBLE
ACROSS ESPECIALLY NORTHEAST PORTIONS OF THE FREEZING RAIN ADVISORY
AREA. AFOREMENTIONED AXIS OF LOW/MID LEVEL MOISTURE CONVERGENCE
SHOULD BE FAIRLY PROGRESSIVE THROUGH NORTHWEST OHIO THROUGH 14Z
WHICH SHOULD MARK AN END TO ANY ADDITIONAL ICE ACCUMULATION. ONLY
WILDCARD FOR THIS FORECAST IS THE POTENTIAL OF UPSTREAM PV ANOMALY
ACROSS MID MS RIVER VALLEY TO IMPINGE ON THIS AXIS OF STRONGER
MOISTURE CONVERGENCE FORCING ACROSS NORTHWEST OHIO...WHICH COULD
YIELD AN INCREASE IN PRECIP COVERAGE/INTENSITY...ESPECIALLY
CONSIDERING THE APPROACH OF A PLUME OF VERY STEEP MID LEVEL LAPSE
RATES. FOR THIS REASON...HAVE CONTINUED TO HOLD THE EASTERN FREEZING
RAIN ADVISORY SEGMENT IN EFFECT UNTIL 10 AM EST...ALTHOUGH WILL
LIKELY BE ABLE TO CLEAR AT LEAST NORTHEAST INDIANA COUNTIES OVER THE
NEXT FEW HOURS. DID REMOVE A ST. JOSEPH INDIANA/WELLS/ADAMS COUNTY
FROM THE ADVISORY WITH SFC TEMPS HAVING RISEN ABOVE FREEZING.

FOR THE REMAINDER OF THE DAY...GUIDANCE STILL SUGGESTS POTENTIAL OF
PRECIP REDEVELOPING IN WEAK DEFORMATION/FGEN AXIS ACROSS NORTHWEST
PORTIONS OF THE AREA LATER THIS MORNING...AND SHIFTING ACROSS THE
REMAINDER OF THE AREA THIS AFTERNOON. IT DOES APPEAR AS THROUGH
LOCAL AREA MAY BE SITUATED BETWEEN THE MORE PRONOUNCED MID/UPPER
LEVEL WAVES THROUGH MOST OF THE AFTERNOON...LENDING TO SOME QUESTION
AS TO EXTENT OF MEASURABLE PRECIP IN THIS WEAK DEFORMATION AXIS.
HAVE MADE SOME SLIGHT DOWNWARD ADJUSTMENTS TO POPS BUT HAVE KEPT
GENERAL IDEA OF PREVIOUS FORECAST INTACT. THERMAL PROFILES SHOULD
SUPPORT MAINLY LIQUID FROM MID TO LATE MORNING ACROSS MOST OF THE
FORECAST AREA...WITH POSSIBLE EXCEPTION ACROSS THE FAR
NORTH/NORTHWEST WHERE SOME LIGHT SNOW/SLEET MAY MIX IN. SFC LOW
PRESSURE REACHING FAR SOUTHERN LAKE HURON THIS AFTERNOON WILL ALLOW
FOR ONSET OF MORE SIGNIFICANT COLD ADVECTION ACROSS ESPECIALLY
WESTERN/NORTHERN LOCATIONS WHERE A BRIEF PERIOD OF MAINLY LIGHT SNOW
IS POSSIBLE ON WESTERN PERIPHERY OF LIGHT DEFORMATION PRECIP.
MARGINAL THERMO PROFILES/LOW LEVEL WET BULBS SUGGEST LITTLE OR NO
SNOW ACCUMULATION HOWEVER. PRESSURE RISE BUBBLE WORKING ACROSS
SOUTHERN IOWA IS EXPECTED TO ENTER THE AREA THIS AFTERNOON...WHICH
SHOULD YIELD SOME WEST NORTHWEST GUSTS TO 20 TO 30 MPH ACCOMPANYING
THE LOW LEVEL CAA.

FOR TONIGHT...LAKE EFFECT/ENHANCED SNOW SHOWERS SHOULD DEVELOP EARLY
THIS EVENING AS WEAK SYNOPTIC UPPER WAVE TRACKS ACROSS THE SOUTHERN
GREAT LAKES. A MORE VIGOROUS WAVE DROPPING OUT OF SOUTH CENTRAL
CANADA WILL BRING MORE PRONOUNCED LOW LEVEL CAA AND INCREASING LAKE
EFFECT CHANCES DURING THE OVERNIGHT HOURS. RELATIVELY DRY MID LEVELS
AND SHALLOW INSTABILITY PROFILES CONTINUE TO SUGGEST MINOR SNOW
ACCUMS OF AN INCH OR TWO POSSIBLE FOR NORTHWEST FETCH LAKE EFFECT
AREAS.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 421 AM EST THU JAN 29 2015

LAKE EFFECT SNOW WILL GRADUALLY WIND DOWN DURING THE DAY FRIDAY.
INCREASING SUBSIDENCE/LOWERING INVERSION...BACKING WINDS...AND DRY
AIR ENTRAINMENT WILL TAKE AN INCREASING TOLL ON LAKE INDUCED
CONVECTION. ACCUMULATING SNOW WILL PROBABLY END BY MIDDAY WITH JUST
SOME RESIDUAL FLURRIES POSSIBLE ACROSS BERRIEN AND CASS COUNTIES
DURING THE AFTERNOON AS LOW LEVEL WINDS BACK TO A MORE WESTERLY
DIRECTION. HIGH TEMPS WILL BE ON THE COOL SIDE WITH THERMAL TROUGH
STILL IN PLACE BUT NOTHING OUT OF THE ORDINARY FOR LATE JANUARY.
EXPECT HIGHS GENERALLY IN THE MID 20S. W/SW LOW LEVEL FLOW DEVELOPS
BY FRIDAY NIGHT AND SATURDAY...ADVECTING SLIGHTLY WARMER AIR INTO
THE REGION AHEAD OF NEXT APPROACHING TROUGH. RAISED HIGHS A BIT TO
BE MORE IN LINE WITH LATEST MOS GUIDANCE. SHOULD MAKE A RUN AT LOWER
30S IN MOST LOCATIONS AFTER OVERNIGHT LOWS IN THE MID TO UPPER TEENS.

ATTENTION THEN TURNS TO POTENTIAL SNOW ON SUNDAY. AS EXPECTED...
DETERMINISTIC MODELS HAVE STRUGGLED IMMENSELY WITH THE EVOLUTION OF
THIS SYSTEM. RUN TO RUN VARIABILITY AND INTERMODEL DISAGREEMENT HAS
BEEN VERY HIGH. THIS IS NOT SURPRISING GIVEN THE EVENT IS PREDICATED
ON A RATHER COMPLEX INTERACTION BETWEEN MULTIPLE JET STREAKS AND
SHORTWAVES THAT HAVE NOT EVEN DEVELOPED YET. GFS ENSEMBLE MEMBERS
STILL SHOW A HIGH DEGREE OF SPREAD AND CONFIDENCE REMAINS VERY LOW.
00Z OPERATIONAL GFS TRENDED A BIT FURTHER NORTH BUT STILL KEEPS BULK
OF THE PRECIP SOUTH OF OUR CWA. LATEST GEM AND NAM EXTRAPOLATION
SUGGEST A STRONGER AND FURTHER NORTH SOLUTION WHILE THE ECMWF
REMAINS THE MOST SUBDUED. WILL LARGELY STAY THE COURSE WITH THIS
FORECAST PACKAGE. STILL MAINTAIN A BETTER THAN 50/50 SHOT OF
MEASURABLE SNOW BASED ON STRENGTH AND PLACEMENT OF UPPER LEVEL JET
SEEN IN ALL OF THE LATEST DETERMINISTIC MODELS...ESPECIALLY THE
FURTHER SOUTH YOU GO. CONFIDENCE IN EXACT AMOUNTS AND LOCATION
REMAIN VERY LOW HOWEVER. STAY TUNED TO THE LATEST FORECASTS OVER THE
NEXT DAY OR TWO AS THE SOLUTION SPACE SHOULD GRADUALLY NARROW.

MUCH COLDER AIR STILL EXPECTED EARLY NEXT WEEK AS 850MB TEMPS DROP
TO AROUND -20C. THIS SHOULD KEEP MONDAY`S HIGHS IN THE TEENS WITH
LOWS SUNDAY AND MONDAY NIGHT IN THE SINGLE DIGITS. BRIEF WARM UP
SEEN ON TUESDAY IN WAA REGIME AHEAD OF ANOTHER CLIPPER SYSTEM BUT
ANOTHER...POSSIBLY COLDER...ARCTIC SURGE IS POSSIBLE FOR THE MIDDLE
AND END OF NEXT WEEK. VERY HIGH AMPLITUDE RIDGE IS SHOWN TO DEVELOP
OVER WESTERN NOAM WITH PERSISTENT TROUGHING OVER EASTERN CANADA
YIELDING VERY COLD N/NW FLOW FOR THE GREAT LAKES.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 658 AM EST THU JAN 29 2015

NO SUBSTANTIAL CHANGES MADE FROM PREVIOUS FORECAST FOR THE 12Z
TAFS. ZONE OF LOW/MID LEVEL MOISTURE CONVERGENCE HAS NOW EXITED
INTO NORTHWEST OHIO TAKING MOST OF THE FREEZING RAIN EAST OF THE
TERMINALS. LIGHT RAIN MAY REDEVELOP LATER THIS MORNING AS A FAIRLY
STRONG UPPER VORT MAX TRACKS INTO THE AREA FROM NORTHERN ILLINOIS.
WEAK DEFORMATION ZONE SHOULD ALLOW FOR RAIN/SNOW TO DEVELOP EARLY
THIS AFTERNOON...EVENTUALLY CHANGING TO PRIMARILY SNOW LATER THIS
AFTERNOON AS COLDER AIR ADVECTS SOUTHWARD. SFC LOW PRESSURE WILL
WORK ACROSS SOUTHERN LAKE HURON THIS AFTERNOON WHICH WILL DRAG A
FRONTAL BOUNDARY EASTWARD ACROSS THE AREA. CIGS ARE EXPECTED TO
DETERIORATE BY MID TO LATE MORNING AS LOW LEVEL REFLECTION
APPROACHES THE AREA...WITH LOWER END MVFR OR IFR CIGS PERSISTING
THROUGH MUCH OF THE DAY. LAKE EFFECT SNOW SHOWERS WILL DEVELOP
TONIGHT...WITH A PERIOD OF IFR VSBYS POSSIBLE AT KSBN LATE IN THE
PERIOD. NORTHWEST WINDS WILL DEVELOP BEHIND THE FRONT THIS
AFTERNOON...WITH GUSTS TO AROUND 25 KNOTS EXPECTED.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...FREEZING RAIN ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ081.

OH...FREEZING RAIN ADVISORY UNTIL 10 AM EST THIS MORNING FOR OHZ001-
     002-004-005-015-016-024-025.

LM...NONE.
&&

$$

SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...AGD
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 290925
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
425 AM EST THU JAN 29 2015

.SYNOPSIS...
ISSUED AT 421 AM EST THU JAN 29 2015

A SERIES OF UPPER LEVEL DISTURBANCES WILL TRACK ACROSS THE REGION
TODAY. AFTER A PERIOD OF LIGHT FREEZING RAIN THIS MORNING ACROSS
SOUTHERN LOWER MICHIGAN...NORTHEAST INDIANA...AND NORTHWEST
OHIO...A MIX OF LIGHT RAIN AND LIGHT SNOW IS THEN EXPECTED THIS
AFTERNOON WITH LITTLE OR NO SNOW ACCUMULATION. COLDER AIR WILL
FILTER INTO THE REGION LATER THIS AFTERNOON INTO TONIGHT BEHIND A
FRONTAL BOUNDARY. THIS WILL PROVIDE THE POTENTIAL OF LIGHT SNOW
ACCUMULATIONS WITH LAKE EFFECT SNOW SHOWERS TONIGHT INTO EARLY FRIDAY.
HIGH TEMPERATURES THIS AFTERNOON WILL RANGE FROM THE MID 30S TO
AROUND 40. LOW TEMPERATURES TONIGHT WILL RANGE FROM THE MID TEENS
TO LOWER 20S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 421 AM EST THU JAN 29 2015

FORECAST CONCERN FOR THE SHORT TERM WILL CONTINUE TO CENTER ON
FREEZING RAIN CHANCES THIS MORNING...FOLLOWED BY POTENTIAL OF
CONTINUED LIGHT PRECIPITATION THROUGH THE DAY AND LAKE EFFECT SNOW
TONIGHT.

PRIMARY FORCING MECHANISM THROUGH MUCH OF THE OVERNIGHT HOURS HAS
BEEN A RELATIVELY NARROW ZONE OF MODERATE TO STRONG LOW/MID LEVEL
MOISTURE CONVERGENCE. THIS AXIS IS SHIFTING ACROSS EXTREME
NORTHEAST INDIANA AND SOUTH CENTRAL LOWER MICHIGAN AS OF 09Z. A
LIGHT GLAZE OF ICE ACCUMULATION WAS RECEIVED AT WFO IWX THIS MORNING
WITH THIS AXIS OF PRECIP. CURRENTLY EXPECTING THE BIGGEST CONCERNS
WILL PERSIST ACROSS EXTREME NORTHEAST INDIANA...FAR NORTHWEST
OHIO...AND SOUTH CENTRAL LOWER MICHIGAN THIS MORNING WHERE NEAR SFC
WARM ADVECTION IS WEAKER...AND NOT ABLE TO FULLY OFFSET EVAPORATIVE
COOLING EFFECTS. UP TO 0.05 INCHES OF ICE ACCUMULATION IS POSSIBLE
ACROSS ESPECIALLY NORTHEAST PORTIONS OF THE FREEZING RAIN ADVISORY
AREA. AFOREMENTIONED AXIS OF LOW/MID LEVEL MOISTURE CONVERGENCE
SHOULD BE FAIRLY PROGRESSIVE THROUGH NORTHWEST OHIO THROUGH 14Z
WHICH SHOULD MARK AN END TO ANY ADDITIONAL ICE ACCUMULATION. ONLY
WILDCARD FOR THIS FORECAST IS THE POTENTIAL OF UPSTREAM PV ANOMALY
ACROSS MID MS RIVER VALLEY TO IMPINGE ON THIS AXIS OF STRONGER
MOISTURE CONVERGENCE FORCING ACROSS NORTHWEST OHIO...WHICH COULD
YIELD AN INCREASE IN PRECIP COVERAGE/INTENSITY...ESPECIALLY
CONSIDERING THE APPROACH OF A PLUME OF VERY STEEP MID LEVEL LAPSE
RATES. FOR THIS REASON...HAVE CONTINUED TO HOLD THE EASTERN FREEZING
RAIN ADVISORY SEGMENT IN EFFECT UNTIL 10 AM EST...ALTHOUGH WILL
LIKELY BE ABLE TO CLEAR AT LEAST NORTHEAST INDIANA COUNTIES OVER THE
NEXT FEW HOURS. DID REMOVE A ST. JOSEPH INDIANA/WELLS/ADAMS COUNTY
FROM THE ADVISORY WITH SFC TEMPS HAVING RISEN ABOVE FREEZING.

FOR THE REMAINDER OF THE DAY...GUIDANCE STILL SUGGESTS POTENTIAL OF
PRECIP REDEVELOPING IN WEAK DEFORMATION/FGEN AXIS ACROSS NORTHWEST
PORTIONS OF THE AREA LATER THIS MORNING...AND SHIFTING ACROSS THE
REMAINDER OF THE AREA THIS AFTERNOON. IT DOES APPEAR AS THROUGH
LOCAL AREA MAY BE SITUATED BETWEEN THE MORE PRONOUNCED MID/UPPER
LEVEL WAVES THROUGH MOST OF THE AFTERNOON...LENDING TO SOME QUESTION
AS TO EXTENT OF MEASURABLE PRECIP IN THIS WEAK DEFORMATION AXIS.
HAVE MADE SOME SLIGHT DOWNWARD ADJUSTMENTS TO POPS BUT HAVE KEPT
GENERAL IDEA OF PREVIOUS FORECAST INTACT. THERMAL PROFILES SHOULD
SUPPORT MAINLY LIQUID FROM MID TO LATE MORNING ACROSS MOST OF THE
FORECAST AREA...WITH POSSIBLE EXCEPTION ACROSS THE FAR
NORTH/NORTHWEST WHERE SOME LIGHT SNOW/SLEET MAY MIX IN. SFC LOW
PRESSURE REACHING FAR SOUTHERN LAKE HURON THIS AFTERNOON WILL ALLOW
FOR ONSET OF MORE SIGNIFICANT COLD ADVECTION ACROSS ESPECIALLY
WESTERN/NORTHERN LOCATIONS WHERE A BRIEF PERIOD OF MAINLY LIGHT SNOW
IS POSSIBLE ON WESTERN PERIPHERY OF LIGHT DEFORMATION PRECIP.
MARGINAL THERMO PROFILES/LOW LEVEL WET BULBS SUGGEST LITTLE OR NO
SNOW ACCUMULATION HOWEVER. PRESSURE RISE BUBBLE WORKING ACROSS
SOUTHERN IOWA IS EXPECTED TO ENTER THE AREA THIS AFTERNOON...WHICH
SHOULD YIELD SOME WEST NORTHWEST GUSTS TO 20 TO 30 MPH ACCOMPANYING
THE LOW LEVEL CAA.

FOR TONIGHT...LAKE EFFECT/ENHANCED SNOW SHOWERS SHOULD DEVELOP EARLY
THIS EVENING AS WEAK SYNOPTIC UPPER WAVE TRACKS ACROSS THE SOUTHERN
GREAT LAKES. A MORE VIGOROUS WAVE DROPPING OUT OF SOUTH CENTRAL
CANADA WILL BRING MORE PRONOUNCED LOW LEVEL CAA AND INCREASING LAKE
EFFECT CHANCES DURING THE OVERNIGHT HOURS. RELATIVELY DRY MID LEVELS
AND SHALLOW INSTABILITY PROFILES CONTINUE TO SUGGEST MINOR SNOW
ACCUMS OF AN INCH OR TWO POSSIBLE FOR NORTHWEST FETCH LAKE EFFECT
AREAS.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 421 AM EST THU JAN 29 2015

LAKE EFFECT SNOW WILL GRADUALLY WIND DOWN DURING THE DAY FRIDAY.
INCREASING SUBSIDENCE/LOWERING INVERSION...BACKING WINDS...AND DRY
AIR ENTRAINMENT WILL TAKE AN INCREASING TOLL ON LAKE INDUCED
CONVECTION. ACCUMULATING SNOW WILL PROBABLY END BY MIDDAY WITH JUST
SOME RESIDUAL FLURRIES POSSIBLE ACROSS BERRIEN AND CASS COUNTIES
DURING THE AFTERNOON AS LOW LEVEL WINDS BACK TO A MORE WESTERLY
DIRECTION. HIGH TEMPS WILL BE ON THE COOL SIDE WITH THERMAL TROUGH
STILL IN PLACE BUT NOTHING OUT OF THE ORDINARY FOR LATE JANUARY.
EXPECT HIGHS GENERALLY IN THE MID 20S. W/SW LOW LEVEL FLOW DEVELOPS
BY FRIDAY NIGHT AND SATURDAY...ADVECTING SLIGHTLY WARMER AIR INTO
THE REGION AHEAD OF NEXT APPROACHING TROUGH. RAISED HIGHS A BIT TO
BE MORE IN LINE WITH LATEST MOS GUIDANCE. SHOULD MAKE A RUN AT LOWER
30S IN MOST LOCATIONS AFTER OVERNIGHT LOWS IN THE MID TO UPPER TEENS.

ATTENTION THEN TURNS TO POTENTIAL SNOW ON SUNDAY. AS EXPECTED...
DETERMINISTIC MODELS HAVE STRUGGLED IMMENSELY WITH THE EVOLUTION OF
THIS SYSTEM. RUN TO RUN VARIABILITY AND INTERMODEL DISAGREEMENT HAS
BEEN VERY HIGH. THIS IS NOT SURPRISING GIVEN THE EVENT IS PREDICATED
ON A RATHER COMPLEX INTERACTION BETWEEN MULTIPLE JET STREAKS AND
SHORTWAVES THAT HAVE NOT EVEN DEVELOPED YET. GFS ENSEMBLE MEMBERS
STILL SHOW A HIGH DEGREE OF SPREAD AND CONFIDENCE REMAINS VERY LOW.
00Z OPERATIONAL GFS TRENDED A BIT FURTHER NORTH BUT STILL KEEPS BULK
OF THE PRECIP SOUTH OF OUR CWA. LATEST GEM AND NAM EXTRAPOLATION
SUGGEST A STRONGER AND FURTHER NORTH SOLUTION WHILE THE ECMWF
REMAINS THE MOST SUBDUED. WILL LARGELY STAY THE COURSE WITH THIS
FORECAST PACKAGE. STILL MAINTAIN A BETTER THAN 50/50 SHOT OF
MEASURABLE SNOW BASED ON STRENGTH AND PLACEMENT OF UPPER LEVEL JET
SEEN IN ALL OF THE LATEST DETERMINISTIC MODELS...ESPECIALLY THE
FURTHER SOUTH YOU GO. CONFIDENCE IN EXACT AMOUNTS AND LOCATION
REMAIN VERY LOW HOWEVER. STAY TUNED TO THE LATEST FORECASTS OVER THE
NEXT DAY OR TWO AS THE SOLUTION SPACE SHOULD GRADUALLY NARROW.

MUCH COLDER AIR STILL EXPECTED EARLY NEXT WEEK AS 850MB TEMPS DROP
TO AROUND -20C. THIS SHOULD KEEP MONDAY`S HIGHS IN THE TEENS WITH
LOWS SUNDAY AND MONDAY NIGHT IN THE SINGLE DIGITS. BRIEF WARM UP
SEEN ON TUESDAY IN WAA REGIME AHEAD OF ANOTHER CLIPPER SYSTEM BUT
ANOTHER...POSSIBLY COLDER...ARCTIC SURGE IS POSSIBLE FOR THE MIDDLE
AND END OF NEXT WEEK. VERY HIGH AMPLITUDE RIDGE IS SHOWN TO DEVELOP
OVER WESTERN NOAM WITH PERSISTENT TROUGHING OVER EASTERN CANADA
YIELDING VERY COLD N/NW FLOW FOR THE GREAT LAKES.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1253 AM EST THU JAN 29 2015

PRIMARY FORECAST CONCERNS FOR THE 06Z TAFS WILL CONTINUE TO BE
POTENTIAL OF A BRIEF PERIOD OF FREEZING RAIN EARLY THIS MORNING
ALONG WITH DETERIORATION TO IFR CONDITIONS EXPECTED AFTER DAYBREAK.
ZONE OF LOW/MID LEVEL MOISTURE CONVERGENCE HAS REACHED NORTHWEST
INDIANA WITH A NARROW SWATH OF LIGHT PRECIP. LOW LEVEL WARM
ADVECTION APPEARS TO BE BALANCING EVAPORATIVE COOLING EFFECTS TO
KEEP SFC TEMPS RIGHT NEAR THE FREEZING MARK OR SLIGHTLY ABOVE. A
VERY BRIEF PERIOD OF -FZRA APPEARS TO BE POSSIBLE AT BOTH
TERMINALS THROUGH 10Z...BUT CURRENT EXPECTATION IS THAT PRECIP
SHOULD CHANGE OVER TO MAINLY RAIN. PRECIP AMOUNTS ARE EXPECTED TO
REMAIN QUITE LIGHT...GENERALLY A FEW HUNDREDTHS OF AN INCH OR
LESS. SFC REFLECTION TO TRACK ACROSS NORTHERN INDIANA THURSDAY
MORNING WITH IFR OR LOWER END MVFR CIGS OVERSPREADING THE AREA FOR
MOST OF THURSDAY. WEAK DEFORMATION ZONE ON BACKSIDE OF THIS SYSTEM
SHOULD ALLOW FOR OCCASIONAL RAIN AND SNOW SHOWERS THROUGH MOST OF
THE DAY BUT LITTLE OR NO SNOW ACCUMULATION IS EXPECTED. WEST
NORTHWEST WINDS WILL BECOME GUSTY IN ASSOCIATION WITH POST COLD
FRONTAL ADVECTION...WITH GUSTS TO AROUND 25 KNOTS EXPECTED FOR THE
AFTERNOON HOURS.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...FREEZING RAIN ADVISORY UNTIL 10 AM EST THIS MORNING FOR INZ007-
     009-018.

     FREEZING RAIN ADVISORY UNTIL 7 AM EST THIS MORNING FOR INZ005-
     006-008-016-017.

MI...FREEZING RAIN ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ080-
     081.

     FREEZING RAIN ADVISORY UNTIL 7 AM EST THIS MORNING FOR
     MIZ077>079.

OH...FREEZING RAIN ADVISORY UNTIL 10 AM EST THIS MORNING FOR OHZ001-
     002-004-005-015-016-024-025.

LM...NONE.
&&

$$

SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...AGD
AVIATION...MARSILI


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 290925
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
425 AM EST THU JAN 29 2015

.SYNOPSIS...
ISSUED AT 421 AM EST THU JAN 29 2015

A SERIES OF UPPER LEVEL DISTURBANCES WILL TRACK ACROSS THE REGION
TODAY. AFTER A PERIOD OF LIGHT FREEZING RAIN THIS MORNING ACROSS
SOUTHERN LOWER MICHIGAN...NORTHEAST INDIANA...AND NORTHWEST
OHIO...A MIX OF LIGHT RAIN AND LIGHT SNOW IS THEN EXPECTED THIS
AFTERNOON WITH LITTLE OR NO SNOW ACCUMULATION. COLDER AIR WILL
FILTER INTO THE REGION LATER THIS AFTERNOON INTO TONIGHT BEHIND A
FRONTAL BOUNDARY. THIS WILL PROVIDE THE POTENTIAL OF LIGHT SNOW
ACCUMULATIONS WITH LAKE EFFECT SNOW SHOWERS TONIGHT INTO EARLY FRIDAY.
HIGH TEMPERATURES THIS AFTERNOON WILL RANGE FROM THE MID 30S TO
AROUND 40. LOW TEMPERATURES TONIGHT WILL RANGE FROM THE MID TEENS
TO LOWER 20S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 421 AM EST THU JAN 29 2015

FORECAST CONCERN FOR THE SHORT TERM WILL CONTINUE TO CENTER ON
FREEZING RAIN CHANCES THIS MORNING...FOLLOWED BY POTENTIAL OF
CONTINUED LIGHT PRECIPITATION THROUGH THE DAY AND LAKE EFFECT SNOW
TONIGHT.

PRIMARY FORCING MECHANISM THROUGH MUCH OF THE OVERNIGHT HOURS HAS
BEEN A RELATIVELY NARROW ZONE OF MODERATE TO STRONG LOW/MID LEVEL
MOISTURE CONVERGENCE. THIS AXIS IS SHIFTING ACROSS EXTREME
NORTHEAST INDIANA AND SOUTH CENTRAL LOWER MICHIGAN AS OF 09Z. A
LIGHT GLAZE OF ICE ACCUMULATION WAS RECEIVED AT WFO IWX THIS MORNING
WITH THIS AXIS OF PRECIP. CURRENTLY EXPECTING THE BIGGEST CONCERNS
WILL PERSIST ACROSS EXTREME NORTHEAST INDIANA...FAR NORTHWEST
OHIO...AND SOUTH CENTRAL LOWER MICHIGAN THIS MORNING WHERE NEAR SFC
WARM ADVECTION IS WEAKER...AND NOT ABLE TO FULLY OFFSET EVAPORATIVE
COOLING EFFECTS. UP TO 0.05 INCHES OF ICE ACCUMULATION IS POSSIBLE
ACROSS ESPECIALLY NORTHEAST PORTIONS OF THE FREEZING RAIN ADVISORY
AREA. AFOREMENTIONED AXIS OF LOW/MID LEVEL MOISTURE CONVERGENCE
SHOULD BE FAIRLY PROGRESSIVE THROUGH NORTHWEST OHIO THROUGH 14Z
WHICH SHOULD MARK AN END TO ANY ADDITIONAL ICE ACCUMULATION. ONLY
WILDCARD FOR THIS FORECAST IS THE POTENTIAL OF UPSTREAM PV ANOMALY
ACROSS MID MS RIVER VALLEY TO IMPINGE ON THIS AXIS OF STRONGER
MOISTURE CONVERGENCE FORCING ACROSS NORTHWEST OHIO...WHICH COULD
YIELD AN INCREASE IN PRECIP COVERAGE/INTENSITY...ESPECIALLY
CONSIDERING THE APPROACH OF A PLUME OF VERY STEEP MID LEVEL LAPSE
RATES. FOR THIS REASON...HAVE CONTINUED TO HOLD THE EASTERN FREEZING
RAIN ADVISORY SEGMENT IN EFFECT UNTIL 10 AM EST...ALTHOUGH WILL
LIKELY BE ABLE TO CLEAR AT LEAST NORTHEAST INDIANA COUNTIES OVER THE
NEXT FEW HOURS. DID REMOVE A ST. JOSEPH INDIANA/WELLS/ADAMS COUNTY
FROM THE ADVISORY WITH SFC TEMPS HAVING RISEN ABOVE FREEZING.

FOR THE REMAINDER OF THE DAY...GUIDANCE STILL SUGGESTS POTENTIAL OF
PRECIP REDEVELOPING IN WEAK DEFORMATION/FGEN AXIS ACROSS NORTHWEST
PORTIONS OF THE AREA LATER THIS MORNING...AND SHIFTING ACROSS THE
REMAINDER OF THE AREA THIS AFTERNOON. IT DOES APPEAR AS THROUGH
LOCAL AREA MAY BE SITUATED BETWEEN THE MORE PRONOUNCED MID/UPPER
LEVEL WAVES THROUGH MOST OF THE AFTERNOON...LENDING TO SOME QUESTION
AS TO EXTENT OF MEASURABLE PRECIP IN THIS WEAK DEFORMATION AXIS.
HAVE MADE SOME SLIGHT DOWNWARD ADJUSTMENTS TO POPS BUT HAVE KEPT
GENERAL IDEA OF PREVIOUS FORECAST INTACT. THERMAL PROFILES SHOULD
SUPPORT MAINLY LIQUID FROM MID TO LATE MORNING ACROSS MOST OF THE
FORECAST AREA...WITH POSSIBLE EXCEPTION ACROSS THE FAR
NORTH/NORTHWEST WHERE SOME LIGHT SNOW/SLEET MAY MIX IN. SFC LOW
PRESSURE REACHING FAR SOUTHERN LAKE HURON THIS AFTERNOON WILL ALLOW
FOR ONSET OF MORE SIGNIFICANT COLD ADVECTION ACROSS ESPECIALLY
WESTERN/NORTHERN LOCATIONS WHERE A BRIEF PERIOD OF MAINLY LIGHT SNOW
IS POSSIBLE ON WESTERN PERIPHERY OF LIGHT DEFORMATION PRECIP.
MARGINAL THERMO PROFILES/LOW LEVEL WET BULBS SUGGEST LITTLE OR NO
SNOW ACCUMULATION HOWEVER. PRESSURE RISE BUBBLE WORKING ACROSS
SOUTHERN IOWA IS EXPECTED TO ENTER THE AREA THIS AFTERNOON...WHICH
SHOULD YIELD SOME WEST NORTHWEST GUSTS TO 20 TO 30 MPH ACCOMPANYING
THE LOW LEVEL CAA.

FOR TONIGHT...LAKE EFFECT/ENHANCED SNOW SHOWERS SHOULD DEVELOP EARLY
THIS EVENING AS WEAK SYNOPTIC UPPER WAVE TRACKS ACROSS THE SOUTHERN
GREAT LAKES. A MORE VIGOROUS WAVE DROPPING OUT OF SOUTH CENTRAL
CANADA WILL BRING MORE PRONOUNCED LOW LEVEL CAA AND INCREASING LAKE
EFFECT CHANCES DURING THE OVERNIGHT HOURS. RELATIVELY DRY MID LEVELS
AND SHALLOW INSTABILITY PROFILES CONTINUE TO SUGGEST MINOR SNOW
ACCUMS OF AN INCH OR TWO POSSIBLE FOR NORTHWEST FETCH LAKE EFFECT
AREAS.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 421 AM EST THU JAN 29 2015

LAKE EFFECT SNOW WILL GRADUALLY WIND DOWN DURING THE DAY FRIDAY.
INCREASING SUBSIDENCE/LOWERING INVERSION...BACKING WINDS...AND DRY
AIR ENTRAINMENT WILL TAKE AN INCREASING TOLL ON LAKE INDUCED
CONVECTION. ACCUMULATING SNOW WILL PROBABLY END BY MIDDAY WITH JUST
SOME RESIDUAL FLURRIES POSSIBLE ACROSS BERRIEN AND CASS COUNTIES
DURING THE AFTERNOON AS LOW LEVEL WINDS BACK TO A MORE WESTERLY
DIRECTION. HIGH TEMPS WILL BE ON THE COOL SIDE WITH THERMAL TROUGH
STILL IN PLACE BUT NOTHING OUT OF THE ORDINARY FOR LATE JANUARY.
EXPECT HIGHS GENERALLY IN THE MID 20S. W/SW LOW LEVEL FLOW DEVELOPS
BY FRIDAY NIGHT AND SATURDAY...ADVECTING SLIGHTLY WARMER AIR INTO
THE REGION AHEAD OF NEXT APPROACHING TROUGH. RAISED HIGHS A BIT TO
BE MORE IN LINE WITH LATEST MOS GUIDANCE. SHOULD MAKE A RUN AT LOWER
30S IN MOST LOCATIONS AFTER OVERNIGHT LOWS IN THE MID TO UPPER TEENS.

ATTENTION THEN TURNS TO POTENTIAL SNOW ON SUNDAY. AS EXPECTED...
DETERMINISTIC MODELS HAVE STRUGGLED IMMENSELY WITH THE EVOLUTION OF
THIS SYSTEM. RUN TO RUN VARIABILITY AND INTERMODEL DISAGREEMENT HAS
BEEN VERY HIGH. THIS IS NOT SURPRISING GIVEN THE EVENT IS PREDICATED
ON A RATHER COMPLEX INTERACTION BETWEEN MULTIPLE JET STREAKS AND
SHORTWAVES THAT HAVE NOT EVEN DEVELOPED YET. GFS ENSEMBLE MEMBERS
STILL SHOW A HIGH DEGREE OF SPREAD AND CONFIDENCE REMAINS VERY LOW.
00Z OPERATIONAL GFS TRENDED A BIT FURTHER NORTH BUT STILL KEEPS BULK
OF THE PRECIP SOUTH OF OUR CWA. LATEST GEM AND NAM EXTRAPOLATION
SUGGEST A STRONGER AND FURTHER NORTH SOLUTION WHILE THE ECMWF
REMAINS THE MOST SUBDUED. WILL LARGELY STAY THE COURSE WITH THIS
FORECAST PACKAGE. STILL MAINTAIN A BETTER THAN 50/50 SHOT OF
MEASURABLE SNOW BASED ON STRENGTH AND PLACEMENT OF UPPER LEVEL JET
SEEN IN ALL OF THE LATEST DETERMINISTIC MODELS...ESPECIALLY THE
FURTHER SOUTH YOU GO. CONFIDENCE IN EXACT AMOUNTS AND LOCATION
REMAIN VERY LOW HOWEVER. STAY TUNED TO THE LATEST FORECASTS OVER THE
NEXT DAY OR TWO AS THE SOLUTION SPACE SHOULD GRADUALLY NARROW.

MUCH COLDER AIR STILL EXPECTED EARLY NEXT WEEK AS 850MB TEMPS DROP
TO AROUND -20C. THIS SHOULD KEEP MONDAY`S HIGHS IN THE TEENS WITH
LOWS SUNDAY AND MONDAY NIGHT IN THE SINGLE DIGITS. BRIEF WARM UP
SEEN ON TUESDAY IN WAA REGIME AHEAD OF ANOTHER CLIPPER SYSTEM BUT
ANOTHER...POSSIBLY COLDER...ARCTIC SURGE IS POSSIBLE FOR THE MIDDLE
AND END OF NEXT WEEK. VERY HIGH AMPLITUDE RIDGE IS SHOWN TO DEVELOP
OVER WESTERN NOAM WITH PERSISTENT TROUGHING OVER EASTERN CANADA
YIELDING VERY COLD N/NW FLOW FOR THE GREAT LAKES.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1253 AM EST THU JAN 29 2015

PRIMARY FORECAST CONCERNS FOR THE 06Z TAFS WILL CONTINUE TO BE
POTENTIAL OF A BRIEF PERIOD OF FREEZING RAIN EARLY THIS MORNING
ALONG WITH DETERIORATION TO IFR CONDITIONS EXPECTED AFTER DAYBREAK.
ZONE OF LOW/MID LEVEL MOISTURE CONVERGENCE HAS REACHED NORTHWEST
INDIANA WITH A NARROW SWATH OF LIGHT PRECIP. LOW LEVEL WARM
ADVECTION APPEARS TO BE BALANCING EVAPORATIVE COOLING EFFECTS TO
KEEP SFC TEMPS RIGHT NEAR THE FREEZING MARK OR SLIGHTLY ABOVE. A
VERY BRIEF PERIOD OF -FZRA APPEARS TO BE POSSIBLE AT BOTH
TERMINALS THROUGH 10Z...BUT CURRENT EXPECTATION IS THAT PRECIP
SHOULD CHANGE OVER TO MAINLY RAIN. PRECIP AMOUNTS ARE EXPECTED TO
REMAIN QUITE LIGHT...GENERALLY A FEW HUNDREDTHS OF AN INCH OR
LESS. SFC REFLECTION TO TRACK ACROSS NORTHERN INDIANA THURSDAY
MORNING WITH IFR OR LOWER END MVFR CIGS OVERSPREADING THE AREA FOR
MOST OF THURSDAY. WEAK DEFORMATION ZONE ON BACKSIDE OF THIS SYSTEM
SHOULD ALLOW FOR OCCASIONAL RAIN AND SNOW SHOWERS THROUGH MOST OF
THE DAY BUT LITTLE OR NO SNOW ACCUMULATION IS EXPECTED. WEST
NORTHWEST WINDS WILL BECOME GUSTY IN ASSOCIATION WITH POST COLD
FRONTAL ADVECTION...WITH GUSTS TO AROUND 25 KNOTS EXPECTED FOR THE
AFTERNOON HOURS.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...FREEZING RAIN ADVISORY UNTIL 10 AM EST THIS MORNING FOR INZ007-
     009-018.

     FREEZING RAIN ADVISORY UNTIL 7 AM EST THIS MORNING FOR INZ005-
     006-008-016-017.

MI...FREEZING RAIN ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ080-
     081.

     FREEZING RAIN ADVISORY UNTIL 7 AM EST THIS MORNING FOR
     MIZ077>079.

OH...FREEZING RAIN ADVISORY UNTIL 10 AM EST THIS MORNING FOR OHZ001-
     002-004-005-015-016-024-025.

LM...NONE.
&&

$$

SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...AGD
AVIATION...MARSILI


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

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







000
FXUS63 KIWX 290600
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
100 AM EST THU JAN 29 2015

.SYNOPSIS...
ISSUED AT 401 AM EST WED JAN 28 2015

CLOUDS WILL INCREASE THIS EVENING AS A RIDGE OF HIGH PRESSURE
SHIFTS OFF TO THE EAST. AN UPPER LEVEL DISTURBANCE ACROSS THE
ROCKIES WILL TRACK INTO THE GREAT LAKES AND OHIO VALLEY REGIONS
TONIGHT BRINGING A WINTRY MIX LATE TONIGHT INTO THURSDAY. SOME
MINOR ICE AND SNOW ACCUMULATIONS ARE POSSIBLE...PARTICULARLY
ACROSS FAR NORTHERN INDIANA...MUCH OF LOWER MICHIGAN...AND
NORTHWEST OHIO.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 359 PM EST WED JAN 28 2015

QUIET/DRY WEATHER CONTINUES INTO THIS EVENING WITH ATTENTION
TURNING TO LIGHT WINTRY MIX LATER TONIGHT/TOMORROW...

MID LEVEL TROP UNDULATION JUST ENTERING WESTERN NE/NORTHEAST CO WILL
TRANSLATE EAST WITH 120-140 METER HEIGHT FALL TRACK AT 500 MB
INTO THE NORTHERN OH VALLEY BY THURSDAY MORNING...WHILE A SEPARATE
NORTHERN STREAM WAVE DROPS OUT OF SOUTH-CENTRAL CANADA INTO THE
WESTERN LAKES BY THURSDAY AFTERNOON. PCPN TIED TO STRONG
ISENTROPIC LIFT/MOISTURE CONVERGENCE WITHIN DOWNSTREAM LLJ/THETA-E
RIDGE (AMPLE MOISTURE AS PWATS SURGE TO 0.80 INCHES AND 1000-850
MB MIXING RATIOS TO 4-5 G/KG WITHIN MOISTURE CHANNEL) SHOULD BREAK
OUT SHORTLY AFTER MIDNIGHT IN NW IN/SW LOWER MI...AND THEN SPREAD
ESE INTO THE REST OF THE FA THROUGH MID MORNING IN ADVANCE OF AN
ELONGATED SFC TROUGH. PCPN MAY BE MORE SPOTTY/SHOWERY DURING THIS
TIME GIVEN OVERSPREAD OF STEEP MID LVL LAPSE RATES AND SLIGHT LAG
OF DEEPER MOISTURE/MID-UPPER LVL ASCENT. SHOULD SEE LIGHT PCPN
FILL IN ALONG AND BEHIND THE SFC TROUGH LATE MORNING THROUGH MID
AFTN ACROSS MAINLY NORTHERN/EASTERN PORTIONS OF THE FORECAST AREA
AS WEAK DEFORMATION FORCING SHIFTS THROUGH. THIS FORCING/DEEPER
MOISTURE THEN EXITS EAST BY LATE AFTERNOON..ALTHOUGH SHOULD SEE
SOME DRIZZLE/LIGHT SNOW SHOWERS LINGER GIVEN SOME LAKE
ENHANCEMENT.

PTYPE INITIALLY STILL EXPECTED TO BE A SLEET/FREEZING RAIN MIX
LATER TONIGHT/EARLY THURSDAY MORNING AS SATURATION/WET BULBING
OCCURS AND WARM LAYER CENTERED AROUND 800 MB OVERSPREADS. SUB
FREEZING SFC AMBIENT TEMPS IN THE NORTH AND EAST LIKELY WITH LIGHT
ICING EXPECTED TOWARD DAYBREAK/MORNING COMMUTE HINTS AT THE
POTENTIAL FOR DIFFICULT TRAVEL FROM LIGHT ICE ACCRETIONS. PER
COLLABORATION AND POOR TIMING WILL ISSUE A HEADLINE FOR THESE
AREAS...WITH CONFIDENCE IN DURATION/MEASURABLE PCPN TOO LOW ACROSS
SOUTHWEST ZONES FOR A HEADLINE ATTM. SFC TEMPS AND ANY ICING
CONCERNS SHOULD ABATE BY LATE MORNING AS WARM/MOIST ADVECTION IN
SOUTHERLY FLOW ALLOWS SFC WET BULB TEMPS TO WARM ABOVE FREEZING.
PTYPE CONTINUES TO BE MESSY INTO THE AFTERNOON...MORE LIGHT
SNOW/SLEET THAN RAIN IN SOUTHERN LOWER MI AND RAIN CHANGING TO
LIGHT SNOW SOUTHERN HALF. DEEP LAYER OF TEMPS WARMER THAN -10C AND
MARGINAL BOUNDARY LAYER TEMPS WILL SIGNIFICANTLY REDUCE SNOW
RATIOS WITH LITTLE TO NO SNOW/SLEET ACCUMULATION EXPECTED.

&&

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 359 PM EST WED JAN 28 2015

STEADY COURSE THIS FORECAST CYCLE. ASSURED THOUGH MODEST/SHALLOW LES
CONVECTION CULMINATING LATE THU NIGHT...WITH LAKE INDUCED CAPE AOB
300 J/KG AND EQL BLO 6KFT. DRY AIR ENTRAINMENT/BACKING STEERING FLOW
AND INCREASED TURBIDITY WITHIN CBL TO SHARPLY DEGRADE RESPONSE BY
MIDDAY FRIDAY. MOST FOCUS ON POSSIBLE SAT NIGHT/SUNDAY SNOW EVENT.
INCREASED MODEL SPREAD LENDING TO LOW CONFIDENCE FOR ANY SIG EVENT.
LATEST ECMWF QUELLS MOISTURE FARTHER SWD THAN PRIOR AND EVEN PRIOR
ALL IN GEM HAS BACKED OFF CONSIDERABLY BUT STILL SLOW/STRONG WITH
GFS WEAK AND DECISIVELY FAST. BEST COURSE OF ACTION ATTM TO
CONT/THOUGH SLIGHTLY LOWER MSRBL POPS FOR LIGHT SNOW EVENT SUN AS
UPSTREAM ATTEMPT TO CONGEAL NOTABLE SHORTWAVE ENERGIES CURRENTLY
LOCATED ACRS NRN CANADA/GULF OF AK/SIBERIAN STRAITS. AT LEAST
80-100M/12 HR HEIGHT FALL CENTROID PER LATEST MIDDLE OF ROAD
ECMWF...ON ORDER OF 50M/12 HR WEAKER THAN PRIOR ITERATION... DROPS
ESEWD FROM NRN PLAINS INTO MID OHIO SHOULD ILLICIT SUFFICIENT DEEP
LAYER ASCENT FOR AT LEAST A LIGHT EVENT. LATER FORECASTS ALLOWED TO
FINE TUNE AS POTENTIAL OUTCOMES HOPEFULLY HONE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1253 AM EST THU JAN 29 2015

PRIMARY FORECAST CONCERNS FOR THE 06Z TAFS WILL CONTINUE TO BE
POTENTIAL OF A BRIEF PERIOD OF FREEZING RAIN EARLY THIS MORNING
ALONG WITH DETERIORATION TO IFR CONDITIONS EXPECTED AFTER DAYBREAK.
ZONE OF LOW/MID LEVEL MOISTURE CONVERGENCE HAS REACHED NORTHWEST
INDIANA WITH A NARROW SWATH OF LIGHT PRECIP. LOW LEVEL WARM
ADVECTION APPEARS TO BE BALANCING EVAPORATIVE COOLING EFFECTS TO
KEEP SFC TEMPS RIGHT NEAR THE FREEZING MARK OR SLIGHTLY ABOVE. A
VERY BRIEF PERIOD OF -FZRA APPEARS TO BE POSSIBLE AT BOTH
TERMINALS THROUGH 10Z...BUT CURRENT EXPECTATION IS THAT PRECIP
SHOULD CHANGE OVER TO MAINLY RAIN. PRECIP AMOUNTS ARE EXPECTED TO
REMAIN QUITE LIGHT...GENERALLY A FEW HUNDREDTHS OF AN INCH OR
LESS. SFC REFLECTION TO TRACK ACROSS NORTHERN INDIANA THURSDAY
MORNING WITH IFR OR LOWER END MVFR CIGS OVERSPREADING THE AREA FOR
MOST OF THURSDAY. WEAK DEFORMATION ZONE ON BACKSIDE OF THIS SYSTEM
SHOULD ALLOW FOR OCCASIONAL RAIN AND SNOW SHOWERS THROUGH MOST OF
THE DAY BUT LITTLE OR NO SNOW ACCUMULATION IS EXPECTED. WEST
NORTHWEST WINDS WILL BECOME GUSTY IN ASSOCIATION WITH POST COLD
FRONTAL ADVECTION...WITH GUSTS TO AROUND 25 KNOTS EXPECTED FOR THE
AFTERNOON HOURS.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...FREEZING RAIN ADVISORY FROM 4 AM TO 10 AM EST THIS MORNING FOR
     INZ007-009-018-026-027.

     FREEZING RAIN ADVISORY UNTIL 9 AM EST THIS MORNING FOR
     INZ004>006-008-016-017.

MI...FREEZING RAIN ADVISORY FROM 4 AM TO 10 AM EST THIS MORNING FOR
     MIZ080-081.

     FREEZING RAIN ADVISORY UNTIL 9 AM EST THIS MORNING FOR
     MIZ077>079.

OH...FREEZING RAIN ADVISORY FROM 4 AM TO 10 AM EST THIS MORNING FOR
     OHZ001-002-004-005-015-016-024-025.

LM...NONE.
&&

$$

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


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

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







000
FXUS63 KIWX 290600
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
100 AM EST THU JAN 29 2015

.SYNOPSIS...
ISSUED AT 401 AM EST WED JAN 28 2015

CLOUDS WILL INCREASE THIS EVENING AS A RIDGE OF HIGH PRESSURE
SHIFTS OFF TO THE EAST. AN UPPER LEVEL DISTURBANCE ACROSS THE
ROCKIES WILL TRACK INTO THE GREAT LAKES AND OHIO VALLEY REGIONS
TONIGHT BRINGING A WINTRY MIX LATE TONIGHT INTO THURSDAY. SOME
MINOR ICE AND SNOW ACCUMULATIONS ARE POSSIBLE...PARTICULARLY
ACROSS FAR NORTHERN INDIANA...MUCH OF LOWER MICHIGAN...AND
NORTHWEST OHIO.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 359 PM EST WED JAN 28 2015

QUIET/DRY WEATHER CONTINUES INTO THIS EVENING WITH ATTENTION
TURNING TO LIGHT WINTRY MIX LATER TONIGHT/TOMORROW...

MID LEVEL TROP UNDULATION JUST ENTERING WESTERN NE/NORTHEAST CO WILL
TRANSLATE EAST WITH 120-140 METER HEIGHT FALL TRACK AT 500 MB
INTO THE NORTHERN OH VALLEY BY THURSDAY MORNING...WHILE A SEPARATE
NORTHERN STREAM WAVE DROPS OUT OF SOUTH-CENTRAL CANADA INTO THE
WESTERN LAKES BY THURSDAY AFTERNOON. PCPN TIED TO STRONG
ISENTROPIC LIFT/MOISTURE CONVERGENCE WITHIN DOWNSTREAM LLJ/THETA-E
RIDGE (AMPLE MOISTURE AS PWATS SURGE TO 0.80 INCHES AND 1000-850
MB MIXING RATIOS TO 4-5 G/KG WITHIN MOISTURE CHANNEL) SHOULD BREAK
OUT SHORTLY AFTER MIDNIGHT IN NW IN/SW LOWER MI...AND THEN SPREAD
ESE INTO THE REST OF THE FA THROUGH MID MORNING IN ADVANCE OF AN
ELONGATED SFC TROUGH. PCPN MAY BE MORE SPOTTY/SHOWERY DURING THIS
TIME GIVEN OVERSPREAD OF STEEP MID LVL LAPSE RATES AND SLIGHT LAG
OF DEEPER MOISTURE/MID-UPPER LVL ASCENT. SHOULD SEE LIGHT PCPN
FILL IN ALONG AND BEHIND THE SFC TROUGH LATE MORNING THROUGH MID
AFTN ACROSS MAINLY NORTHERN/EASTERN PORTIONS OF THE FORECAST AREA
AS WEAK DEFORMATION FORCING SHIFTS THROUGH. THIS FORCING/DEEPER
MOISTURE THEN EXITS EAST BY LATE AFTERNOON..ALTHOUGH SHOULD SEE
SOME DRIZZLE/LIGHT SNOW SHOWERS LINGER GIVEN SOME LAKE
ENHANCEMENT.

PTYPE INITIALLY STILL EXPECTED TO BE A SLEET/FREEZING RAIN MIX
LATER TONIGHT/EARLY THURSDAY MORNING AS SATURATION/WET BULBING
OCCURS AND WARM LAYER CENTERED AROUND 800 MB OVERSPREADS. SUB
FREEZING SFC AMBIENT TEMPS IN THE NORTH AND EAST LIKELY WITH LIGHT
ICING EXPECTED TOWARD DAYBREAK/MORNING COMMUTE HINTS AT THE
POTENTIAL FOR DIFFICULT TRAVEL FROM LIGHT ICE ACCRETIONS. PER
COLLABORATION AND POOR TIMING WILL ISSUE A HEADLINE FOR THESE
AREAS...WITH CONFIDENCE IN DURATION/MEASURABLE PCPN TOO LOW ACROSS
SOUTHWEST ZONES FOR A HEADLINE ATTM. SFC TEMPS AND ANY ICING
CONCERNS SHOULD ABATE BY LATE MORNING AS WARM/MOIST ADVECTION IN
SOUTHERLY FLOW ALLOWS SFC WET BULB TEMPS TO WARM ABOVE FREEZING.
PTYPE CONTINUES TO BE MESSY INTO THE AFTERNOON...MORE LIGHT
SNOW/SLEET THAN RAIN IN SOUTHERN LOWER MI AND RAIN CHANGING TO
LIGHT SNOW SOUTHERN HALF. DEEP LAYER OF TEMPS WARMER THAN -10C AND
MARGINAL BOUNDARY LAYER TEMPS WILL SIGNIFICANTLY REDUCE SNOW
RATIOS WITH LITTLE TO NO SNOW/SLEET ACCUMULATION EXPECTED.

&&

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 359 PM EST WED JAN 28 2015

STEADY COURSE THIS FORECAST CYCLE. ASSURED THOUGH MODEST/SHALLOW LES
CONVECTION CULMINATING LATE THU NIGHT...WITH LAKE INDUCED CAPE AOB
300 J/KG AND EQL BLO 6KFT. DRY AIR ENTRAINMENT/BACKING STEERING FLOW
AND INCREASED TURBIDITY WITHIN CBL TO SHARPLY DEGRADE RESPONSE BY
MIDDAY FRIDAY. MOST FOCUS ON POSSIBLE SAT NIGHT/SUNDAY SNOW EVENT.
INCREASED MODEL SPREAD LENDING TO LOW CONFIDENCE FOR ANY SIG EVENT.
LATEST ECMWF QUELLS MOISTURE FARTHER SWD THAN PRIOR AND EVEN PRIOR
ALL IN GEM HAS BACKED OFF CONSIDERABLY BUT STILL SLOW/STRONG WITH
GFS WEAK AND DECISIVELY FAST. BEST COURSE OF ACTION ATTM TO
CONT/THOUGH SLIGHTLY LOWER MSRBL POPS FOR LIGHT SNOW EVENT SUN AS
UPSTREAM ATTEMPT TO CONGEAL NOTABLE SHORTWAVE ENERGIES CURRENTLY
LOCATED ACRS NRN CANADA/GULF OF AK/SIBERIAN STRAITS. AT LEAST
80-100M/12 HR HEIGHT FALL CENTROID PER LATEST MIDDLE OF ROAD
ECMWF...ON ORDER OF 50M/12 HR WEAKER THAN PRIOR ITERATION... DROPS
ESEWD FROM NRN PLAINS INTO MID OHIO SHOULD ILLICIT SUFFICIENT DEEP
LAYER ASCENT FOR AT LEAST A LIGHT EVENT. LATER FORECASTS ALLOWED TO
FINE TUNE AS POTENTIAL OUTCOMES HOPEFULLY HONE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1253 AM EST THU JAN 29 2015

PRIMARY FORECAST CONCERNS FOR THE 06Z TAFS WILL CONTINUE TO BE
POTENTIAL OF A BRIEF PERIOD OF FREEZING RAIN EARLY THIS MORNING
ALONG WITH DETERIORATION TO IFR CONDITIONS EXPECTED AFTER DAYBREAK.
ZONE OF LOW/MID LEVEL MOISTURE CONVERGENCE HAS REACHED NORTHWEST
INDIANA WITH A NARROW SWATH OF LIGHT PRECIP. LOW LEVEL WARM
ADVECTION APPEARS TO BE BALANCING EVAPORATIVE COOLING EFFECTS TO
KEEP SFC TEMPS RIGHT NEAR THE FREEZING MARK OR SLIGHTLY ABOVE. A
VERY BRIEF PERIOD OF -FZRA APPEARS TO BE POSSIBLE AT BOTH
TERMINALS THROUGH 10Z...BUT CURRENT EXPECTATION IS THAT PRECIP
SHOULD CHANGE OVER TO MAINLY RAIN. PRECIP AMOUNTS ARE EXPECTED TO
REMAIN QUITE LIGHT...GENERALLY A FEW HUNDREDTHS OF AN INCH OR
LESS. SFC REFLECTION TO TRACK ACROSS NORTHERN INDIANA THURSDAY
MORNING WITH IFR OR LOWER END MVFR CIGS OVERSPREADING THE AREA FOR
MOST OF THURSDAY. WEAK DEFORMATION ZONE ON BACKSIDE OF THIS SYSTEM
SHOULD ALLOW FOR OCCASIONAL RAIN AND SNOW SHOWERS THROUGH MOST OF
THE DAY BUT LITTLE OR NO SNOW ACCUMULATION IS EXPECTED. WEST
NORTHWEST WINDS WILL BECOME GUSTY IN ASSOCIATION WITH POST COLD
FRONTAL ADVECTION...WITH GUSTS TO AROUND 25 KNOTS EXPECTED FOR THE
AFTERNOON HOURS.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...FREEZING RAIN ADVISORY FROM 4 AM TO 10 AM EST THIS MORNING FOR
     INZ007-009-018-026-027.

     FREEZING RAIN ADVISORY UNTIL 9 AM EST THIS MORNING FOR
     INZ004>006-008-016-017.

MI...FREEZING RAIN ADVISORY FROM 4 AM TO 10 AM EST THIS MORNING FOR
     MIZ080-081.

     FREEZING RAIN ADVISORY UNTIL 9 AM EST THIS MORNING FOR
     MIZ077>079.

OH...FREEZING RAIN ADVISORY FROM 4 AM TO 10 AM EST THIS MORNING FOR
     OHZ001-002-004-005-015-016-024-025.

LM...NONE.
&&

$$

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


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

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSIWX
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000
FXUS63 KIWX 282343
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
643 PM EST WED JAN 28 2015

.SYNOPSIS...
ISSUED AT 401 AM EST WED JAN 28 2015

CLOUDS WILL INCREASE THIS EVENING AS A RIDGE OF HIGH PRESSURE
SHIFTS OFF TO THE EAST. AN UPPER LEVEL DISTURBANCE ACROSS THE
ROCKIES WILL TRACK INTO THE GREAT LAKES AND OHIO VALLEY REGIONS
TONIGHT BRINGING A WINTRY MIX LATE TONIGHT INTO THURSDAY. SOME
MINOR ICE AND SNOW ACCUMULATIONS ARE POSSIBLE...PARTICULARLY
ACROSS FAR NORTHERN INDIANA...MUCH OF LOWER MICHIGAN...AND
NORTHWEST OHIO.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 359 PM EST WED JAN 28 2015

QUIET/DRY WEATHER CONTINUES INTO THIS EVENING WITH ATTENTION
TURNING TO LIGHT WINTRY MIX LATER TONIGHT/TOMORROW...

MID LEVEL TROP UNDULATION JUST ENTERING WESTERN NE/NORTHEAST CO WILL
TRANSLATE EAST WITH 120-140 METER HEIGHT FALL TRACK AT 500 MB
INTO THE NORTHERN OH VALLEY BY THURSDAY MORNING...WHILE A SEPARATE
NORTHERN STREAM WAVE DROPS OUT OF SOUTH-CENTRAL CANADA INTO THE
WESTERN LAKES BY THURSDAY AFTERNOON. PCPN TIED TO STRONG
ISENTROPIC LIFT/MOISTURE CONVERGENCE WITHIN DOWNSTREAM LLJ/THETA-E
RIDGE (AMPLE MOISTURE AS PWATS SURGE TO 0.80 INCHES AND 1000-850
MB MIXING RATIOS TO 4-5 G/KG WITHIN MOISTURE CHANNEL) SHOULD BREAK
OUT SHORTLY AFTER MIDNIGHT IN NW IN/SW LOWER MI...AND THEN SPREAD
ESE INTO THE REST OF THE FA THROUGH MID MORNING IN ADVANCE OF AN
ELONGATED SFC TROUGH. PCPN MAY BE MORE SPOTTY/SHOWERY DURING THIS
TIME GIVEN OVERSPREAD OF STEEP MID LVL LAPSE RATES AND SLIGHT LAG
OF DEEPER MOISTURE/MID-UPPER LVL ASCENT. SHOULD SEE LIGHT PCPN
FILL IN ALONG AND BEHIND THE SFC TROUGH LATE MORNING THROUGH MID
AFTN ACROSS MAINLY NORTHERN/EASTERN PORTIONS OF THE FORECAST AREA
AS WEAK DEFORMATION FORCING SHIFTS THROUGH. THIS FORCING/DEEPER
MOISTURE THEN EXITS EAST BY LATE AFTERNOON..ALTHOUGH SHOULD SEE
SOME DRIZZLE/LIGHT SNOW SHOWERS LINGER GIVEN SOME LAKE
ENHANCEMENT.

PTYPE INITIALLY STILL EXPECTED TO BE A SLEET/FREEZING RAIN MIX
LATER TONIGHT/EARLY THURSDAY MORNING AS SATURATION/WET BULBING
OCCURS AND WARM LAYER CENTERED AROUND 800 MB OVERSPREADS. SUB
FREEZING SFC AMBIENT TEMPS IN THE NORTH AND EAST LIKELY WITH LIGHT
ICING EXPECTED TOWARD DAYBREAK/MORNING COMMUTE HINTS AT THE
POTENTIAL FOR DIFFICULT TRAVEL FROM LIGHT ICE ACCRETIONS. PER
COLLABORATION AND POOR TIMING WILL ISSUE A HEADLINE FOR THESE
AREAS...WITH CONFIDENCE IN DURATION/MEASURABLE PCPN TOO LOW ACROSS
SOUTHWEST ZONES FOR A HEADLINE ATTM. SFC TEMPS AND ANY ICING
CONCERNS SHOULD ABATE BY LATE MORNING AS WARM/MOIST ADVECTION IN
SOUTHERLY FLOW ALLOWS SFC WET BULB TEMPS TO WARM ABOVE FREEZING.
PTYPE CONTINUES TO BE MESSY INTO THE AFTERNOON...MORE LIGHT
SNOW/SLEET THAN RAIN IN SOUTHERN LOWER MI AND RAIN CHANGING TO
LIGHT SNOW SOUTHERN HALF. DEEP LAYER OF TEMPS WARMER THAN -10C AND
MARGINAL BOUNDARY LAYER TEMPS WILL SIGNIFICANTLY REDUCE SNOW
RATIOS WITH LITTLE TO NO SNOW/SLEET ACCUMULATION EXPECTED.

&&

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 359 PM EST WED JAN 28 2015

STEADY COURSE THIS FORECAST CYCLE. ASSURED THOUGH MODEST/SHALLOW LES
CONVECTION CULMINATING LATE THU NIGHT...WITH LAKE INDUCED CAPE AOB
300 J/KG AND EQL BLO 6KFT. DRY AIR ENTRAINMENT/BACKING STEERING FLOW
AND INCREASED TURBIDITY WITHIN CBL TO SHARPLY DEGRADE RESPONSE BY
MIDDAY FRIDAY. MOST FOCUS ON POSSIBLE SAT NIGHT/SUNDAY SNOW EVENT.
INCREASED MODEL SPREAD LENDING TO LOW CONFIDENCE FOR ANY SIG EVENT.
LATEST ECMWF QUELLS MOISTURE FARTHER SWD THAN PRIOR AND EVEN PRIOR
ALL IN GEM HAS BACKED OFF CONSIDERABLY BUT STILL SLOW/STRONG WITH
GFS WEAK AND DECISIVELY FAST. BEST COURSE OF ACTION ATTM TO
CONT/THOUGH SLIGHTLY LOWER MSRBL POPS FOR LIGHT SNOW EVENT SUN AS
UPSTREAM ATTEMPT TO CONGEAL NOTABLE SHORTWAVE ENERGIES CURRENTLY
LOCATED ACRS NRN CANADA/GULF OF AK/SIBERIAN STRAITS. AT LEAST
80-100M/12 HR HEIGHT FALL CENTROID PER LATEST MIDDLE OF ROAD
ECMWF...ON ORDER OF 50M/12 HR WEAKER THAN PRIOR ITERATION... DROPS
ESEWD FROM NRN PLAINS INTO MID OHIO SHOULD ILLICIT SUFFICIENT DEEP
LAYER ASCENT FOR AT LEAST A LIGHT EVENT. LATER FORECASTS ALLOWED TO
FINE TUNE AS POTENTIAL OUTCOMES HOPEFULLY HONE.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 637 PM EST WED JAN 28 2015

VFR CONDS XPCD TO BEGIN W/DETERIORATION TO IFR XPCD THU AM.

QUICKLY RAMPING LL FLW WILL OCCUR TWD MID EVENING AS UPSTREAM STG
LLJ AHD OF SEWD DIGGING DISTURBANCE DROPPING OUT OF SK. ATTENDANT
PD OF LLWS WILL DVLP AND PERSIST INTO DAYBREAK BFR SHIFTING EWD.
SLW MSTR RTN AND NWD TRACK OF BTR LIFT LOOKS TO PRECLUDE PD OF
FREEZING PCPN LTR THIS EVENING AND DROPPED PRIOR PROB30 MENTION IN
LIGHT OF LATEST AGREEABLE NR TERM GUIDANCE.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...FREEZING RAIN ADVISORY FROM 6 AM TO 10 AM EST THURSDAY FOR
     INZ007-009-018-026-027.

     FREEZING RAIN ADVISORY FROM 4 AM TO 9 AM EST THURSDAY FOR
     INZ004>006-008-016-017.

MI...FREEZING RAIN ADVISORY FROM 6 AM TO 10 AM EST THURSDAY FOR
     MIZ080-081.

     FREEZING RAIN ADVISORY FROM 4 AM TO 9 AM EST THURSDAY FOR
     MIZ077>079.

OH...FREEZING RAIN ADVISORY FROM 6 AM TO 10 AM EST THURSDAY FOR
     OHZ001-002-004-005-015-016-024-025.

LM...NONE.
&&

$$

SYNOPSIS...MARSILI
SHORT TERM...STEINWEDEL
LONG TERM...MURPHY
AVIATION...T


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 282343
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
643 PM EST WED JAN 28 2015

.SYNOPSIS...
ISSUED AT 401 AM EST WED JAN 28 2015

CLOUDS WILL INCREASE THIS EVENING AS A RIDGE OF HIGH PRESSURE
SHIFTS OFF TO THE EAST. AN UPPER LEVEL DISTURBANCE ACROSS THE
ROCKIES WILL TRACK INTO THE GREAT LAKES AND OHIO VALLEY REGIONS
TONIGHT BRINGING A WINTRY MIX LATE TONIGHT INTO THURSDAY. SOME
MINOR ICE AND SNOW ACCUMULATIONS ARE POSSIBLE...PARTICULARLY
ACROSS FAR NORTHERN INDIANA...MUCH OF LOWER MICHIGAN...AND
NORTHWEST OHIO.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 359 PM EST WED JAN 28 2015

QUIET/DRY WEATHER CONTINUES INTO THIS EVENING WITH ATTENTION
TURNING TO LIGHT WINTRY MIX LATER TONIGHT/TOMORROW...

MID LEVEL TROP UNDULATION JUST ENTERING WESTERN NE/NORTHEAST CO WILL
TRANSLATE EAST WITH 120-140 METER HEIGHT FALL TRACK AT 500 MB
INTO THE NORTHERN OH VALLEY BY THURSDAY MORNING...WHILE A SEPARATE
NORTHERN STREAM WAVE DROPS OUT OF SOUTH-CENTRAL CANADA INTO THE
WESTERN LAKES BY THURSDAY AFTERNOON. PCPN TIED TO STRONG
ISENTROPIC LIFT/MOISTURE CONVERGENCE WITHIN DOWNSTREAM LLJ/THETA-E
RIDGE (AMPLE MOISTURE AS PWATS SURGE TO 0.80 INCHES AND 1000-850
MB MIXING RATIOS TO 4-5 G/KG WITHIN MOISTURE CHANNEL) SHOULD BREAK
OUT SHORTLY AFTER MIDNIGHT IN NW IN/SW LOWER MI...AND THEN SPREAD
ESE INTO THE REST OF THE FA THROUGH MID MORNING IN ADVANCE OF AN
ELONGATED SFC TROUGH. PCPN MAY BE MORE SPOTTY/SHOWERY DURING THIS
TIME GIVEN OVERSPREAD OF STEEP MID LVL LAPSE RATES AND SLIGHT LAG
OF DEEPER MOISTURE/MID-UPPER LVL ASCENT. SHOULD SEE LIGHT PCPN
FILL IN ALONG AND BEHIND THE SFC TROUGH LATE MORNING THROUGH MID
AFTN ACROSS MAINLY NORTHERN/EASTERN PORTIONS OF THE FORECAST AREA
AS WEAK DEFORMATION FORCING SHIFTS THROUGH. THIS FORCING/DEEPER
MOISTURE THEN EXITS EAST BY LATE AFTERNOON..ALTHOUGH SHOULD SEE
SOME DRIZZLE/LIGHT SNOW SHOWERS LINGER GIVEN SOME LAKE
ENHANCEMENT.

PTYPE INITIALLY STILL EXPECTED TO BE A SLEET/FREEZING RAIN MIX
LATER TONIGHT/EARLY THURSDAY MORNING AS SATURATION/WET BULBING
OCCURS AND WARM LAYER CENTERED AROUND 800 MB OVERSPREADS. SUB
FREEZING SFC AMBIENT TEMPS IN THE NORTH AND EAST LIKELY WITH LIGHT
ICING EXPECTED TOWARD DAYBREAK/MORNING COMMUTE HINTS AT THE
POTENTIAL FOR DIFFICULT TRAVEL FROM LIGHT ICE ACCRETIONS. PER
COLLABORATION AND POOR TIMING WILL ISSUE A HEADLINE FOR THESE
AREAS...WITH CONFIDENCE IN DURATION/MEASURABLE PCPN TOO LOW ACROSS
SOUTHWEST ZONES FOR A HEADLINE ATTM. SFC TEMPS AND ANY ICING
CONCERNS SHOULD ABATE BY LATE MORNING AS WARM/MOIST ADVECTION IN
SOUTHERLY FLOW ALLOWS SFC WET BULB TEMPS TO WARM ABOVE FREEZING.
PTYPE CONTINUES TO BE MESSY INTO THE AFTERNOON...MORE LIGHT
SNOW/SLEET THAN RAIN IN SOUTHERN LOWER MI AND RAIN CHANGING TO
LIGHT SNOW SOUTHERN HALF. DEEP LAYER OF TEMPS WARMER THAN -10C AND
MARGINAL BOUNDARY LAYER TEMPS WILL SIGNIFICANTLY REDUCE SNOW
RATIOS WITH LITTLE TO NO SNOW/SLEET ACCUMULATION EXPECTED.

&&

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 359 PM EST WED JAN 28 2015

STEADY COURSE THIS FORECAST CYCLE. ASSURED THOUGH MODEST/SHALLOW LES
CONVECTION CULMINATING LATE THU NIGHT...WITH LAKE INDUCED CAPE AOB
300 J/KG AND EQL BLO 6KFT. DRY AIR ENTRAINMENT/BACKING STEERING FLOW
AND INCREASED TURBIDITY WITHIN CBL TO SHARPLY DEGRADE RESPONSE BY
MIDDAY FRIDAY. MOST FOCUS ON POSSIBLE SAT NIGHT/SUNDAY SNOW EVENT.
INCREASED MODEL SPREAD LENDING TO LOW CONFIDENCE FOR ANY SIG EVENT.
LATEST ECMWF QUELLS MOISTURE FARTHER SWD THAN PRIOR AND EVEN PRIOR
ALL IN GEM HAS BACKED OFF CONSIDERABLY BUT STILL SLOW/STRONG WITH
GFS WEAK AND DECISIVELY FAST. BEST COURSE OF ACTION ATTM TO
CONT/THOUGH SLIGHTLY LOWER MSRBL POPS FOR LIGHT SNOW EVENT SUN AS
UPSTREAM ATTEMPT TO CONGEAL NOTABLE SHORTWAVE ENERGIES CURRENTLY
LOCATED ACRS NRN CANADA/GULF OF AK/SIBERIAN STRAITS. AT LEAST
80-100M/12 HR HEIGHT FALL CENTROID PER LATEST MIDDLE OF ROAD
ECMWF...ON ORDER OF 50M/12 HR WEAKER THAN PRIOR ITERATION... DROPS
ESEWD FROM NRN PLAINS INTO MID OHIO SHOULD ILLICIT SUFFICIENT DEEP
LAYER ASCENT FOR AT LEAST A LIGHT EVENT. LATER FORECASTS ALLOWED TO
FINE TUNE AS POTENTIAL OUTCOMES HOPEFULLY HONE.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 637 PM EST WED JAN 28 2015

VFR CONDS XPCD TO BEGIN W/DETERIORATION TO IFR XPCD THU AM.

QUICKLY RAMPING LL FLW WILL OCCUR TWD MID EVENING AS UPSTREAM STG
LLJ AHD OF SEWD DIGGING DISTURBANCE DROPPING OUT OF SK. ATTENDANT
PD OF LLWS WILL DVLP AND PERSIST INTO DAYBREAK BFR SHIFTING EWD.
SLW MSTR RTN AND NWD TRACK OF BTR LIFT LOOKS TO PRECLUDE PD OF
FREEZING PCPN LTR THIS EVENING AND DROPPED PRIOR PROB30 MENTION IN
LIGHT OF LATEST AGREEABLE NR TERM GUIDANCE.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...FREEZING RAIN ADVISORY FROM 6 AM TO 10 AM EST THURSDAY FOR
     INZ007-009-018-026-027.

     FREEZING RAIN ADVISORY FROM 4 AM TO 9 AM EST THURSDAY FOR
     INZ004>006-008-016-017.

MI...FREEZING RAIN ADVISORY FROM 6 AM TO 10 AM EST THURSDAY FOR
     MIZ080-081.

     FREEZING RAIN ADVISORY FROM 4 AM TO 9 AM EST THURSDAY FOR
     MIZ077>079.

OH...FREEZING RAIN ADVISORY FROM 6 AM TO 10 AM EST THURSDAY FOR
     OHZ001-002-004-005-015-016-024-025.

LM...NONE.
&&

$$

SYNOPSIS...MARSILI
SHORT TERM...STEINWEDEL
LONG TERM...MURPHY
AVIATION...T


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 282059
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
359 PM EST WED JAN 28 2015

.SYNOPSIS...
ISSUED AT 401 AM EST WED JAN 28 2015

CLOUDS WILL INCREASE THIS EVENING AS A RIDGE OF HIGH PRESSURE
SHIFTS OFF TO THE EAST. AN UPPER LEVEL DISTURBANCE ACROSS THE
ROCKIES WILL TRACK INTO THE GREAT LAKES AND OHIO VALLEY REGIONS
TONIGHT BRINGING A WINTRY MIX LATE TONIGHT INTO THURSDAY. SOME
MINOR ICE AND SNOW ACCUMULATIONS ARE POSSIBLE...PARTICULARLY
ACROSS FAR NORTHERN INDIANA...MUCH OF LOWER MICHIGAN...AND
NORTHWEST OHIO.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 359 PM EST WED JAN 28 2015

QUIET/DRY WEATHER CONTINUES INTO THIS EVENING WITH ATTENTION
TURNING TO LIGHT WINTRY MIX LATER TONIGHT/TOMORROW...

MID LEVEL TROP UNDULATION JUST ENTERING WESTERN NE/NORTHEAST CO WILL
TRANSLATE EAST WITH 120-140 METER HEIGHT FALL TRACK AT 500 MB
INTO THE NORTHERN OH VALLEY BY THURSDAY MORNING...WHILE A SEPARATE
NORTHERN STREAM WAVE DROPS OUT OF SOUTH-CENTRAL CANADA INTO THE
WESTERN LAKES BY THURSDAY AFTERNOON. PCPN TIED TO STRONG
ISENTROPIC LIFT/MOISTURE CONVERGENCE WITHIN DOWNSTREAM LLJ/THETA-E
RIDGE (AMPLE MOISTURE AS PWATS SURGE TO 0.80 INCHES AND 1000-850
MB MIXING RATIOS TO 4-5 G/KG WITHIN MOISTURE CHANNEL) SHOULD BREAK
OUT SHORTLY AFTER MIDNIGHT IN NW IN/SW LOWER MI...AND THEN SPREAD
ESE INTO THE REST OF THE FA THROUGH MID MORNING IN ADVANCE OF AN
ELONGATED SFC TROUGH. PCPN MAY BE MORE SPOTTY/SHOWERY DURING THIS
TIME GIVEN OVERSPREAD OF STEEP MID LVL LAPSE RATES AND SLIGHT LAG
OF DEEPER MOISTURE/MID-UPPER LVL ASCENT. SHOULD SEE LIGHT PCPN
FILL IN ALONG AND BEHIND THE SFC TROUGH LATE MORNING THROUGH MID
AFTN ACROSS MAINLY NORTHERN/EASTERN PORTIONS OF THE FORECAST AREA
AS WEAK DEFORMATION FORCING SHIFTS THROUGH. THIS FORCING/DEEPER
MOISTURE THEN EXITS EAST BY LATE AFTERNOON..ALTHOUGH SHOULD SEE
SOME DRIZZLE/LIGHT SNOW SHOWERS LINGER GIVEN SOME LAKE
ENHANCEMENT.

PTYPE INITIALLY STILL EXPECTED TO BE A SLEET/FREEZING RAIN MIX
LATER TONIGHT/EARLY THURSDAY MORNING AS SATURATION/WET BULBING
OCCURS AND WARM LAYER CENTERED AROUND 800 MB OVERSPREADS. SUB
FREEZING SFC AMBIENT TEMPS IN THE NORTH AND EAST LIKELY WITH LIGHT
ICING EXPECTED TOWARD DAYBREAK/MORNING COMMUTE HINTS AT THE
POTENTIAL FOR DIFFICULT TRAVEL FROM LIGHT ICE ACCRETIONS. PER
COLLABORATION AND POOR TIMING WILL ISSUE A HEADLINE FOR THESE
AREAS...WITH CONFIDENCE IN DURATION/MEASURABLE PCPN TOO LOW ACROSS
SOUTHWEST ZONES FOR A HEADLINE ATTM. SFC TEMPS AND ANY ICING
CONCERNS SHOULD ABATE BY LATE MORNING AS WARM/MOIST ADVECTION IN
SOUTHERLY FLOW ALLOWS SFC WET BULB TEMPS TO WARM ABOVE FREEZING.
PTYPE CONTINUES TO BE MESSY INTO THE AFTERNOON...MORE LIGHT
SNOW/SLEET THAN RAIN IN SOUTHERN LOWER MI AND RAIN CHANGING TO
LIGHT SNOW SOUTHERN HALF. DEEP LAYER OF TEMPS WARMER THAN -10C AND
MARGINAL BOUNDARY LAYER TEMPS WILL SIGNIFICANTLY REDUCE SNOW
RATIOS WITH LITTLE TO NO SNOW/SLEET ACCUMULATION EXPECTED.

&&

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 359 PM EST WED JAN 28 2015

STEADY COURSE THIS FORECAST CYCLE. ASSURED THOUGH MODEST/SHALLOW LES
CONVECTION CULMINATING LATE THU NIGHT...WITH LAKE INDUCED CAPE AOB
300 J/KG AND EQL BLO 6KFT. DRY AIR ENTRAINMENT/BACKING STEERING FLOW
AND INCREASED TURBIDITY WITHIN CBL TO SHARPLY DEGRADE RESPONSE BY
MIDDAY FRIDAY. MOST FOCUS ON POSSIBLE SAT NIGHT/SUNDAY SNOW EVENT.
INCREASED MODEL SPREAD LENDING TO LOW CONFIDENCE FOR ANY SIG EVENT.
LATEST ECMWF QUELLS MOISTURE FARTHER SWD THAN PRIOR AND EVEN PRIOR
ALL IN GEM HAS BACKED OFF CONSIDERABLY BUT STILL SLOW/STRONG WITH
GFS WEAK AND DECISIVELY FAST. BEST COURSE OF ACTION ATTM TO
CONT/THOUGH SLIGHTLY LOWER MSRBL POPS FOR LIGHT SNOW EVENT SUN AS
UPSTREAM ATTEMPT TO CONGEAL NOTABLE SHORTWAVE ENERGIES CURRENTLY
LOCATED ACRS NRN CANADA/GULF OF AK/SIBERIAN STRAITS. AT LEAST
80-100M/12 HR HEIGHT FALL CENTROID PER LATEST MIDDLE OF ROAD
ECMWF...ON ORDER OF 50M/12 HR WEAKER THAN PRIOR ITERATION... DROPS
ESEWD FROM NRN PLAINS INTO MID OHIO SHOULD ILLICIT SUFFICIENT DEEP
LAYER ASCENT FOR AT LEAST A LIGHT EVENT. LATER FORECASTS ALLOWED TO
FINE TUNE AS POTENTIAL OUTCOMES HOPEFULLY HONE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1213 PM EST WED JAN 28 2015

VFR WITH A GRADUAL INCREASE IN SOUTHERLY WINDS AND MID-HIGH LEVEL
CLOUDS CAN BE EXPECTED THIS AFTERNOON AS WARM ADVECTION COMMENCES.
MOISTURE CHANNEL WITHIN RAMPING LOW LEVEL JET WILL DRIFT EAST OVER
NORTHERN INDIANA LATER TONIGHT INTO EARLY THURSDAY MORNING IN
ADVANCE OF AN APPROACHING MID LEVEL DISTURBANCE AND ELONGATED SFC
TROUGH. THE RESULT WILL BE DETERIORATING FLIGHT CONDITIONS AND
INCREASING CHANCES FOR RAIN SHOWERS (FREEZING RAIN POSSIBLE AT
ONSET) DURING THIS TIME.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...FREEZING RAIN ADVISORY FROM 6 AM TO 10 AM EST THURSDAY FOR
     INZ007-009-018-026-027.

     FREEZING RAIN ADVISORY FROM 4 AM TO 9 AM EST THURSDAY FOR
     INZ004>006-008-016-017.

MI...FREEZING RAIN ADVISORY FROM 6 AM TO 10 AM EST THURSDAY FOR
     MIZ080-081.

     FREEZING RAIN ADVISORY FROM 4 AM TO 9 AM EST THURSDAY FOR
     MIZ077>079.

OH...FREEZING RAIN ADVISORY FROM 6 AM TO 10 AM EST THURSDAY FOR
     OHZ001-002-004-005-015-016-024-025.

LM...NONE.
&&

$$

SYNOPSIS...MARSILI
SHORT TERM...STEINWEDEL
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 282059
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
359 PM EST WED JAN 28 2015

.SYNOPSIS...
ISSUED AT 401 AM EST WED JAN 28 2015

CLOUDS WILL INCREASE THIS EVENING AS A RIDGE OF HIGH PRESSURE
SHIFTS OFF TO THE EAST. AN UPPER LEVEL DISTURBANCE ACROSS THE
ROCKIES WILL TRACK INTO THE GREAT LAKES AND OHIO VALLEY REGIONS
TONIGHT BRINGING A WINTRY MIX LATE TONIGHT INTO THURSDAY. SOME
MINOR ICE AND SNOW ACCUMULATIONS ARE POSSIBLE...PARTICULARLY
ACROSS FAR NORTHERN INDIANA...MUCH OF LOWER MICHIGAN...AND
NORTHWEST OHIO.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 359 PM EST WED JAN 28 2015

QUIET/DRY WEATHER CONTINUES INTO THIS EVENING WITH ATTENTION
TURNING TO LIGHT WINTRY MIX LATER TONIGHT/TOMORROW...

MID LEVEL TROP UNDULATION JUST ENTERING WESTERN NE/NORTHEAST CO WILL
TRANSLATE EAST WITH 120-140 METER HEIGHT FALL TRACK AT 500 MB
INTO THE NORTHERN OH VALLEY BY THURSDAY MORNING...WHILE A SEPARATE
NORTHERN STREAM WAVE DROPS OUT OF SOUTH-CENTRAL CANADA INTO THE
WESTERN LAKES BY THURSDAY AFTERNOON. PCPN TIED TO STRONG
ISENTROPIC LIFT/MOISTURE CONVERGENCE WITHIN DOWNSTREAM LLJ/THETA-E
RIDGE (AMPLE MOISTURE AS PWATS SURGE TO 0.80 INCHES AND 1000-850
MB MIXING RATIOS TO 4-5 G/KG WITHIN MOISTURE CHANNEL) SHOULD BREAK
OUT SHORTLY AFTER MIDNIGHT IN NW IN/SW LOWER MI...AND THEN SPREAD
ESE INTO THE REST OF THE FA THROUGH MID MORNING IN ADVANCE OF AN
ELONGATED SFC TROUGH. PCPN MAY BE MORE SPOTTY/SHOWERY DURING THIS
TIME GIVEN OVERSPREAD OF STEEP MID LVL LAPSE RATES AND SLIGHT LAG
OF DEEPER MOISTURE/MID-UPPER LVL ASCENT. SHOULD SEE LIGHT PCPN
FILL IN ALONG AND BEHIND THE SFC TROUGH LATE MORNING THROUGH MID
AFTN ACROSS MAINLY NORTHERN/EASTERN PORTIONS OF THE FORECAST AREA
AS WEAK DEFORMATION FORCING SHIFTS THROUGH. THIS FORCING/DEEPER
MOISTURE THEN EXITS EAST BY LATE AFTERNOON..ALTHOUGH SHOULD SEE
SOME DRIZZLE/LIGHT SNOW SHOWERS LINGER GIVEN SOME LAKE
ENHANCEMENT.

PTYPE INITIALLY STILL EXPECTED TO BE A SLEET/FREEZING RAIN MIX
LATER TONIGHT/EARLY THURSDAY MORNING AS SATURATION/WET BULBING
OCCURS AND WARM LAYER CENTERED AROUND 800 MB OVERSPREADS. SUB
FREEZING SFC AMBIENT TEMPS IN THE NORTH AND EAST LIKELY WITH LIGHT
ICING EXPECTED TOWARD DAYBREAK/MORNING COMMUTE HINTS AT THE
POTENTIAL FOR DIFFICULT TRAVEL FROM LIGHT ICE ACCRETIONS. PER
COLLABORATION AND POOR TIMING WILL ISSUE A HEADLINE FOR THESE
AREAS...WITH CONFIDENCE IN DURATION/MEASURABLE PCPN TOO LOW ACROSS
SOUTHWEST ZONES FOR A HEADLINE ATTM. SFC TEMPS AND ANY ICING
CONCERNS SHOULD ABATE BY LATE MORNING AS WARM/MOIST ADVECTION IN
SOUTHERLY FLOW ALLOWS SFC WET BULB TEMPS TO WARM ABOVE FREEZING.
PTYPE CONTINUES TO BE MESSY INTO THE AFTERNOON...MORE LIGHT
SNOW/SLEET THAN RAIN IN SOUTHERN LOWER MI AND RAIN CHANGING TO
LIGHT SNOW SOUTHERN HALF. DEEP LAYER OF TEMPS WARMER THAN -10C AND
MARGINAL BOUNDARY LAYER TEMPS WILL SIGNIFICANTLY REDUCE SNOW
RATIOS WITH LITTLE TO NO SNOW/SLEET ACCUMULATION EXPECTED.

&&

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 359 PM EST WED JAN 28 2015

STEADY COURSE THIS FORECAST CYCLE. ASSURED THOUGH MODEST/SHALLOW LES
CONVECTION CULMINATING LATE THU NIGHT...WITH LAKE INDUCED CAPE AOB
300 J/KG AND EQL BLO 6KFT. DRY AIR ENTRAINMENT/BACKING STEERING FLOW
AND INCREASED TURBIDITY WITHIN CBL TO SHARPLY DEGRADE RESPONSE BY
MIDDAY FRIDAY. MOST FOCUS ON POSSIBLE SAT NIGHT/SUNDAY SNOW EVENT.
INCREASED MODEL SPREAD LENDING TO LOW CONFIDENCE FOR ANY SIG EVENT.
LATEST ECMWF QUELLS MOISTURE FARTHER SWD THAN PRIOR AND EVEN PRIOR
ALL IN GEM HAS BACKED OFF CONSIDERABLY BUT STILL SLOW/STRONG WITH
GFS WEAK AND DECISIVELY FAST. BEST COURSE OF ACTION ATTM TO
CONT/THOUGH SLIGHTLY LOWER MSRBL POPS FOR LIGHT SNOW EVENT SUN AS
UPSTREAM ATTEMPT TO CONGEAL NOTABLE SHORTWAVE ENERGIES CURRENTLY
LOCATED ACRS NRN CANADA/GULF OF AK/SIBERIAN STRAITS. AT LEAST
80-100M/12 HR HEIGHT FALL CENTROID PER LATEST MIDDLE OF ROAD
ECMWF...ON ORDER OF 50M/12 HR WEAKER THAN PRIOR ITERATION... DROPS
ESEWD FROM NRN PLAINS INTO MID OHIO SHOULD ILLICIT SUFFICIENT DEEP
LAYER ASCENT FOR AT LEAST A LIGHT EVENT. LATER FORECASTS ALLOWED TO
FINE TUNE AS POTENTIAL OUTCOMES HOPEFULLY HONE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1213 PM EST WED JAN 28 2015

VFR WITH A GRADUAL INCREASE IN SOUTHERLY WINDS AND MID-HIGH LEVEL
CLOUDS CAN BE EXPECTED THIS AFTERNOON AS WARM ADVECTION COMMENCES.
MOISTURE CHANNEL WITHIN RAMPING LOW LEVEL JET WILL DRIFT EAST OVER
NORTHERN INDIANA LATER TONIGHT INTO EARLY THURSDAY MORNING IN
ADVANCE OF AN APPROACHING MID LEVEL DISTURBANCE AND ELONGATED SFC
TROUGH. THE RESULT WILL BE DETERIORATING FLIGHT CONDITIONS AND
INCREASING CHANCES FOR RAIN SHOWERS (FREEZING RAIN POSSIBLE AT
ONSET) DURING THIS TIME.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...FREEZING RAIN ADVISORY FROM 6 AM TO 10 AM EST THURSDAY FOR
     INZ007-009-018-026-027.

     FREEZING RAIN ADVISORY FROM 4 AM TO 9 AM EST THURSDAY FOR
     INZ004>006-008-016-017.

MI...FREEZING RAIN ADVISORY FROM 6 AM TO 10 AM EST THURSDAY FOR
     MIZ080-081.

     FREEZING RAIN ADVISORY FROM 4 AM TO 9 AM EST THURSDAY FOR
     MIZ077>079.

OH...FREEZING RAIN ADVISORY FROM 6 AM TO 10 AM EST THURSDAY FOR
     OHZ001-002-004-005-015-016-024-025.

LM...NONE.
&&

$$

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


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

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSIWX
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000
FXUS63 KIWX 281722
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1222 PM EST WED JAN 28 2015

.SYNOPSIS...
ISSUED AT 401 AM EST WED JAN 28 2015

CLOUDS WILL INCREASE TODAY AS A RIDGE OF HIGH PRESSURE SHIFTS OFF TO
THE EAST. AN UPPER LEVEL DISTURBANCE ACROSS THE ROCKIES WILL TRACK
INTO THE GREAT LAKES AND OHIO VALLEY REGIONS TONIGHT BRINGING A
WINTRY MIX LATE TONIGHT INTO THURSDAY. SOME MINOR ICE AND SNOW
ACCUMULATIONS ARE POSSIBLE...PARTICULARLY ACROSS FAR NORTHERN
INDIANA...MUCH OF LOWER MICHIGAN...AND NORTHWEST OHIO. HIGH
TEMPERATURES TODAY WILL RANGE FROM THE UPPER 30S ACROSS NORTHEAST
ILLINOIS TO THE UPPER 20S ACROSS NORTHWEST OHIO AND SOUTHEAST LOWER
MICHIGAN. STEADY OR SLOWLY RISING TEMPERATURES ARE EXPECTED THROUGH
MUCH OF TONIGHT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM EST WED JAN 28 2015

AFTER CONTINUED QUIET WEATHER CONDITIONS TODAY...ATTENTION FOR
TONIGHT WILL TURN TO NEXT SYSTEM THAT COULD BRING A WINTRY MIX TO
THE AREA INTO THURSDAY.

LARGE SCALE SUBSIDENCE CONTINUES EARLY THIS MORNING AS UPSTREAM
UPPER LEVEL RIDGE AXIS BEGINS TO SHIFT EASTWARD ACROSS THE SOUTHERN
GREAT LAKES TODAY. SOUTHERLY FLOW WILL INCREASE TOADY AS LOW LEVEL
ANTICYCLONE SHIFTS EASTWARD...WITH MAINLY JUST AN INCREASE IN MID
AND HIGH LEVEL CLOUDINESS THROUGH THE DAY AS MID LEVEL WAA
STRENGTHENS MORE SUBSTANTIALLY LATE THIS AFTERNOON. DESPITE
STRENGTHENING LOW LEVEL WAA LATER...A VERY STRONG LOW LEVEL
INVERSION WILL LIMIT AFTERNOON TEMPS...ESPECIALLY CONSIDERING
THICKENING MID LEVEL CLOUDS LATER THIS AFTERNOON. PREVIOUS
FORECASTED MAX TEMPS FROM LOWER TO MID 30S WEST...TO UPPER 20S
EAST...STILL APPEAR REASONABLE.

A FAIRLY ROBUST UPPER LEVEL PV ANOMALY APPROACHING THE ROCKIES
THIS MORNING WILL REACH THE SOUTHERN GREAT LAKES/OHIO VALLEY BY
EARLY THURSDAY MORNING. AN AXIS OF 40-50 KNOT SOUTHWESTERLY LOW
LEVEL FLOW PRECEDING THIS UPPER PV ANOMALY WILL ALLOW FOR ZONE OF
STRONG ISENTROPIC LIFT AND AN AXIS OF LOW/MID LEVEL MOISTURE
CONVERGENCE WORKING FROM WEST TO EAST ACROSS THE AREA THIS EVENING
INTO THE EARLY PORTIONS OF THE OVERNIGHT. DIFFERENTIAL WARM
ADVECTION WILL ALSO ALLOW PLUME OF FAIRLY STEEP MID LEVEL LAPSE
RATES TO OVERSPREAD THE AREA DURING THE EVENING HOURS. WHILE UPPER
FORCING WILL STILL LAG TO THE WEST FOR MUCH OF THE NIGHT...NAM/GFS
DO DEPICT STRENGTHENING 850-700 HPA QVEC CONVG SIGNAL OVERSPREADING
AREA THIS EVENING...WHICH WILL BE FOLLOWED BY PERIOD OF MORE
PRONOUNCED UPPER FORCING LATE TONIGHT INTO EARLY THURSDAY.

PTYPE QUESTIONS STILL ARE THE MAIN CONCERN WITH THIS SYSTEM AS
SUBSTANTIAL LOW LEVEL WARM LAYER ADVECTING INTO THE AREA AND AN
INITIALLY DRY LOW/MID LEVEL AIR MASS (EVAPORATIVE COOLING EFFECTS)
WILL MAKE FOR CHALLENGING FORECAST. DID MAINTAIN SOME LOW TO MID
RANGE CHANCE POPS LATE EVENING INTO THE EARLY PORTION OF OVERNIGHT
GIVEN AXIS OF STRONG LOW/MID LEVEL THETAE ADVECTION AND STEEPENING
MID LEVEL LAPSE RATES...WITH SOME LIGHT FREEZING RAIN POSSIBLE
ESPECIALLY AT PRECIP ONSET. IT DOES APPEAR AS THOUGH PRECIP ACROSS
THE WEST SHOULD TRANSITION TO LIQUID AS PRIMARY LOW LEVEL MOISTURE
AXIS SHIFTS INTO THE AREA ALONG WITH NON-DIURNAL TEMP CURVE AND
TEMPS RISING INTO THE MID 30S. ACROSS THE FAR NORTH AND
PARTICULARLY THE NORTHEAST PORTIONS OF THE CWA WHERE A WEAKER WARM
LAYER IS EXPECTED...MIXED PRECIP IN THE FORM OF LIGHT FREEZING
RAIN/SLEET/SNOW MAY BE MORE OF AN ISSUE THROUGH EARLY THURSDAY
MORNING. SOME LIGHT ICE ACCUMULATION IS POSSIBLE MAINLY NORTH OF
ROUTE 30...WITH PERHAPS BEST CHANCE OF MEASURABLE ICE ACCUMULATION
ACROSS EXTREME NORTHEAST INDIANA INTO PORTIONS OF SOUTH CENTRAL
LOWER MICHIGAN AND NORTHWEST OHIO. CONFIDENCE IN MIXED PRECIP
DURATION/LOCATION A BIT TOO LOW FOR ANY HEADLINES AT THIS TIME BUT
WILL NEED TO MONITOR THIS CLOSELY DUE TO TIMING WITH THURSDAY
MORNING COMMUTE. THE POSSIBILITY DOES EXIST THAT AN ADVISORY WILL
BE NEEDED FOR THIS PERIOD FOR PORTIONS OF THE AREA.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 401 AM EST WED JAN 28 2015

ACTIVE LONG TERM PERIOD WITH NUMEROUS ISSUES TO DISCUSS. THURSDAY`S
WINTRY MIX AND POTENTIAL SUNDAY STORM ARE THE PRIMARY ITEMS OF NOTE
BUT THERE WILL BE INTERMEDIATE PERIODS OF LAKE EFFECT SNOW AS WELL
AND AT LEAST A BRIEF RETURN TO MUCH COLDER TEMPS EARLY NEXT WEEK.

PRECIP TYPES FOR THURSDAY STILL APPEAR VERY MESSY. CONTINUED WARM
AND MOIST AIR ADVECTION WITH STRONG SOUTHERLY WINDS AT THE SURFACE
WILL PUSH WET BULB TEMPS ABOVE FREEZING BY THURSDAY MORNING.
FREEZING RAIN SHOULD TRANSITION TO JUST RAIN BY 12Z THURSDAY IN ALL
BUT OUR FAR NORTHEAST COUNTIES WHERE IT MAY PERSIST FOR AN HOUR OR
TWO LONGER. HOWEVER...ARRIVAL OF SECONDARY NORTHERN STREAM VORT MAX
WILL DO TWO THINGS. ONE...INCREASE COVERAGE OF MEASURABLE PRECIP IN
OUR CWA FOR THE MIDDAY PERIOD WITH AN ADDED BUMP OF CVA-FORCED
ASCENT IN A VERY MOIST ENVIRONMENT. AND TWO...ALLOW COLDER AIR TO
FILTER BACK INTO THE AREA BEHIND SURFACE LOW TRACKING EASTWARD. THIS
WILL FORCE A CHANGEOVER TO SNOW FROM NORTH TO SOUTH DURING THE
AFTERNOON WITH A PERIOD OF SLEET ALSO POSSIBLE DURING THE
TRANSITION. EXPECTING LITTLE IF ANY ACCUMULATION THOUGH. TROWAL AXIS
AND BEST MIDLEVEL CVA BYPASS US TO THE NORTH AND WARM/WET GROUND
WILL PREVENT MOST OF WHAT DOES FALL FROM ACCUMULATING. THINK A FEW
TENTHS AT BEST FOR MOST AREAS WITH UP TO AN INCH POSSIBLE IN OUR FAR
NORTHEAST COUNTIES.

SYNOPTICALLY DRIVEN SNOW WILL EXIT BY THURSDAY EVENING BUT LAKE
EFFECT WILL LIKELY CRANK UP TO SOME DEGREE OVERNIGHT. 850MB TEMPS
WILL DROP TO ROUGHLY -16C BEHIND A THIRD SHORTWAVE DIVING THROUGH
THE CENTRAL GREAT LAKES AROUND 06Z. NEARLY IDEAL 340 DEGREE FETCH
DEVELOPS BUT LAKE INDUCED CONVECTION WILL BE BATTLING INCREASING DRY
AIR ENTRAINMENT AND A STRENGTHENING SUBSIDENCE INVERSION. CONVECTIVE
DEPTHS ARE ONLY AROUND 5 KFT AND DROP EVEN LOWER BY FRIDAY MORNING.
ON THE OTHER HAND...MUCH OF THE LAKE EFFECT CLOUD LAYER WILL BE IN
THE PREFERRED -12 TO -18C DENDRITIC GROWTH ZONE (ESPECIALLY BY LATE
THURSDAY NIGHT) AND BOTH NAM AND GFS BUFR SOUNDINGS SHOW GOOD
SUPERSATURATION WITH RESPECT TO ICE IN THAT LAYER. NOT EXPECTING ANY
SIGNIFICANT ACCUMULATIONS BUT AN INCH OR TWO IS CERTAINLY POSSIBLE
IN BERRIEN COUNTY AND HAVE RAISED POPS ACCORDINGLY. OTHER COUNTIES
MAY ALSO SEE A LIGHT DUSTING WITH STRONG BOUNDARY LAYER WINDS LIKELY
PUSHING ORPHANED BANDS PRETTY FAR INLAND.

NOW ON TO THE ELEPHANT IN THE ROOM. 00Z DETERMINISTIC GUIDANCE
TRENDED MUCH SLOWER...DEEPER...AND FURTHER NORTHWEST WITH THE
MIDLATITUDE CYCLONE SLATED TO DEVELOP OVER THE EASTERN CONUS LATE
SUNDAY. 00Z GFS IN PARTICULAR PAINTS AN OMINOUS PICTURE. HOWEVER...A
PRUDENT AND JUDICIOUS APPROACH IS DEMANDED AT THESE TIME RANGES.
CIRCUMSTANCES THAT CONSPIRE TO PRODUCE STORM DEPICTED IN THE 00Z GFS
ARE COMPLICATED TO SAY THE LEAST...INVOLVING THE INTERACTION OF
SOUTHWEST CONUS CUTOFF LOW AND TWO DISTINCT NORTHERN STREAM
SHORTWAVES THAT ARE SHOWN TO PHASE AND PRODUCE A STRONG/NEGATIVELY
TILTED TROUGH OVER THE OHIO VALLEY. SHORTWAVES IN QUESTION HAVE NOT
EVEN DEVELOPED YET MUCH LESS BEEN SAMPLED. FURTHERMORE...ENSEMBLE
MEMBERS STILL SHOW A HIGH DEGREE OF SPREAD AND ECMWF DEPICTS A LESS
ROBUST CYCLONE. RUN TO RUN VARIABILITY HAS ALSO BEEN VERY HIGH FOR
THIS TIME RANGE. ALL OF THIS IS TO SAY THAT FORECAST CONFIDENCE IS
VERY LOW AT THIS POINT...MUCH LOWER THAN EVEN A TYPICAL DAY5
FORECAST. CERTAINLY THE CHANCES FOR PRECIP ON SUNDAY ARE INCREASING
AND THE NEW FORECAST REFLECTS THAT BUT DETAILS REGARDING AMOUNTS AND
TYPES ARE VERY MUCH IN FLUX. STAY TUNED TO THE LATEST FORECASTS OVER
THE COMING DAYS AS DETAILS ARE ALMOST CERTAIN TO CHANGE.

STILL EXPECTING A BLAST OF MUCH COLDER AIR BEHIND THIS SYSTEM EARLY
NEXT WEEK. HIGHS WILL LIKELY REMAIN IN THE TEENS WITH OVERNIGHT LOWS
POTENTIALLY IN THE NEGATIVE SINGLE DIGITS. A BRIEF SHOT OF LAKE
EFFECT SNOW IS ALSO POSSIBLE IN THE COLD WAKE OF EXITING CYCLONE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1213 PM EST WED JAN 28 2015

VFR WITH A GRADUAL INCREASE IN SOUTHERLY WINDS AND MID-HIGH LEVEL
CLOUDS CAN BE EXPECTED THIS AFTERNOON AS WARM ADVECTION COMMENCES.
MOISTURE CHANNEL WITHIN RAMPING LOW LEVEL JET WILL DRIFT EAST OVER
NORTHERN INDIANA LATER TONIGHT INTO EARLY THURSDAY MORNING IN
ADVANCE OF AN APPROACHING MID LEVEL DISTURBANCE AND ELONGATED SFC
TROUGH. THE RESULT WILL BE DETERIORATING FLIGHT CONDITIONS AND
INCREASING CHANCES FOR RAIN SHOWERS (FREEZING RAIN POSSIBLE AT
ONSET) DURING THIS TIME.

&&

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

$$

SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...AGD
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 281722
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1222 PM EST WED JAN 28 2015

.SYNOPSIS...
ISSUED AT 401 AM EST WED JAN 28 2015

CLOUDS WILL INCREASE TODAY AS A RIDGE OF HIGH PRESSURE SHIFTS OFF TO
THE EAST. AN UPPER LEVEL DISTURBANCE ACROSS THE ROCKIES WILL TRACK
INTO THE GREAT LAKES AND OHIO VALLEY REGIONS TONIGHT BRINGING A
WINTRY MIX LATE TONIGHT INTO THURSDAY. SOME MINOR ICE AND SNOW
ACCUMULATIONS ARE POSSIBLE...PARTICULARLY ACROSS FAR NORTHERN
INDIANA...MUCH OF LOWER MICHIGAN...AND NORTHWEST OHIO. HIGH
TEMPERATURES TODAY WILL RANGE FROM THE UPPER 30S ACROSS NORTHEAST
ILLINOIS TO THE UPPER 20S ACROSS NORTHWEST OHIO AND SOUTHEAST LOWER
MICHIGAN. STEADY OR SLOWLY RISING TEMPERATURES ARE EXPECTED THROUGH
MUCH OF TONIGHT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM EST WED JAN 28 2015

AFTER CONTINUED QUIET WEATHER CONDITIONS TODAY...ATTENTION FOR
TONIGHT WILL TURN TO NEXT SYSTEM THAT COULD BRING A WINTRY MIX TO
THE AREA INTO THURSDAY.

LARGE SCALE SUBSIDENCE CONTINUES EARLY THIS MORNING AS UPSTREAM
UPPER LEVEL RIDGE AXIS BEGINS TO SHIFT EASTWARD ACROSS THE SOUTHERN
GREAT LAKES TODAY. SOUTHERLY FLOW WILL INCREASE TOADY AS LOW LEVEL
ANTICYCLONE SHIFTS EASTWARD...WITH MAINLY JUST AN INCREASE IN MID
AND HIGH LEVEL CLOUDINESS THROUGH THE DAY AS MID LEVEL WAA
STRENGTHENS MORE SUBSTANTIALLY LATE THIS AFTERNOON. DESPITE
STRENGTHENING LOW LEVEL WAA LATER...A VERY STRONG LOW LEVEL
INVERSION WILL LIMIT AFTERNOON TEMPS...ESPECIALLY CONSIDERING
THICKENING MID LEVEL CLOUDS LATER THIS AFTERNOON. PREVIOUS
FORECASTED MAX TEMPS FROM LOWER TO MID 30S WEST...TO UPPER 20S
EAST...STILL APPEAR REASONABLE.

A FAIRLY ROBUST UPPER LEVEL PV ANOMALY APPROACHING THE ROCKIES
THIS MORNING WILL REACH THE SOUTHERN GREAT LAKES/OHIO VALLEY BY
EARLY THURSDAY MORNING. AN AXIS OF 40-50 KNOT SOUTHWESTERLY LOW
LEVEL FLOW PRECEDING THIS UPPER PV ANOMALY WILL ALLOW FOR ZONE OF
STRONG ISENTROPIC LIFT AND AN AXIS OF LOW/MID LEVEL MOISTURE
CONVERGENCE WORKING FROM WEST TO EAST ACROSS THE AREA THIS EVENING
INTO THE EARLY PORTIONS OF THE OVERNIGHT. DIFFERENTIAL WARM
ADVECTION WILL ALSO ALLOW PLUME OF FAIRLY STEEP MID LEVEL LAPSE
RATES TO OVERSPREAD THE AREA DURING THE EVENING HOURS. WHILE UPPER
FORCING WILL STILL LAG TO THE WEST FOR MUCH OF THE NIGHT...NAM/GFS
DO DEPICT STRENGTHENING 850-700 HPA QVEC CONVG SIGNAL OVERSPREADING
AREA THIS EVENING...WHICH WILL BE FOLLOWED BY PERIOD OF MORE
PRONOUNCED UPPER FORCING LATE TONIGHT INTO EARLY THURSDAY.

PTYPE QUESTIONS STILL ARE THE MAIN CONCERN WITH THIS SYSTEM AS
SUBSTANTIAL LOW LEVEL WARM LAYER ADVECTING INTO THE AREA AND AN
INITIALLY DRY LOW/MID LEVEL AIR MASS (EVAPORATIVE COOLING EFFECTS)
WILL MAKE FOR CHALLENGING FORECAST. DID MAINTAIN SOME LOW TO MID
RANGE CHANCE POPS LATE EVENING INTO THE EARLY PORTION OF OVERNIGHT
GIVEN AXIS OF STRONG LOW/MID LEVEL THETAE ADVECTION AND STEEPENING
MID LEVEL LAPSE RATES...WITH SOME LIGHT FREEZING RAIN POSSIBLE
ESPECIALLY AT PRECIP ONSET. IT DOES APPEAR AS THOUGH PRECIP ACROSS
THE WEST SHOULD TRANSITION TO LIQUID AS PRIMARY LOW LEVEL MOISTURE
AXIS SHIFTS INTO THE AREA ALONG WITH NON-DIURNAL TEMP CURVE AND
TEMPS RISING INTO THE MID 30S. ACROSS THE FAR NORTH AND
PARTICULARLY THE NORTHEAST PORTIONS OF THE CWA WHERE A WEAKER WARM
LAYER IS EXPECTED...MIXED PRECIP IN THE FORM OF LIGHT FREEZING
RAIN/SLEET/SNOW MAY BE MORE OF AN ISSUE THROUGH EARLY THURSDAY
MORNING. SOME LIGHT ICE ACCUMULATION IS POSSIBLE MAINLY NORTH OF
ROUTE 30...WITH PERHAPS BEST CHANCE OF MEASURABLE ICE ACCUMULATION
ACROSS EXTREME NORTHEAST INDIANA INTO PORTIONS OF SOUTH CENTRAL
LOWER MICHIGAN AND NORTHWEST OHIO. CONFIDENCE IN MIXED PRECIP
DURATION/LOCATION A BIT TOO LOW FOR ANY HEADLINES AT THIS TIME BUT
WILL NEED TO MONITOR THIS CLOSELY DUE TO TIMING WITH THURSDAY
MORNING COMMUTE. THE POSSIBILITY DOES EXIST THAT AN ADVISORY WILL
BE NEEDED FOR THIS PERIOD FOR PORTIONS OF THE AREA.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 401 AM EST WED JAN 28 2015

ACTIVE LONG TERM PERIOD WITH NUMEROUS ISSUES TO DISCUSS. THURSDAY`S
WINTRY MIX AND POTENTIAL SUNDAY STORM ARE THE PRIMARY ITEMS OF NOTE
BUT THERE WILL BE INTERMEDIATE PERIODS OF LAKE EFFECT SNOW AS WELL
AND AT LEAST A BRIEF RETURN TO MUCH COLDER TEMPS EARLY NEXT WEEK.

PRECIP TYPES FOR THURSDAY STILL APPEAR VERY MESSY. CONTINUED WARM
AND MOIST AIR ADVECTION WITH STRONG SOUTHERLY WINDS AT THE SURFACE
WILL PUSH WET BULB TEMPS ABOVE FREEZING BY THURSDAY MORNING.
FREEZING RAIN SHOULD TRANSITION TO JUST RAIN BY 12Z THURSDAY IN ALL
BUT OUR FAR NORTHEAST COUNTIES WHERE IT MAY PERSIST FOR AN HOUR OR
TWO LONGER. HOWEVER...ARRIVAL OF SECONDARY NORTHERN STREAM VORT MAX
WILL DO TWO THINGS. ONE...INCREASE COVERAGE OF MEASURABLE PRECIP IN
OUR CWA FOR THE MIDDAY PERIOD WITH AN ADDED BUMP OF CVA-FORCED
ASCENT IN A VERY MOIST ENVIRONMENT. AND TWO...ALLOW COLDER AIR TO
FILTER BACK INTO THE AREA BEHIND SURFACE LOW TRACKING EASTWARD. THIS
WILL FORCE A CHANGEOVER TO SNOW FROM NORTH TO SOUTH DURING THE
AFTERNOON WITH A PERIOD OF SLEET ALSO POSSIBLE DURING THE
TRANSITION. EXPECTING LITTLE IF ANY ACCUMULATION THOUGH. TROWAL AXIS
AND BEST MIDLEVEL CVA BYPASS US TO THE NORTH AND WARM/WET GROUND
WILL PREVENT MOST OF WHAT DOES FALL FROM ACCUMULATING. THINK A FEW
TENTHS AT BEST FOR MOST AREAS WITH UP TO AN INCH POSSIBLE IN OUR FAR
NORTHEAST COUNTIES.

SYNOPTICALLY DRIVEN SNOW WILL EXIT BY THURSDAY EVENING BUT LAKE
EFFECT WILL LIKELY CRANK UP TO SOME DEGREE OVERNIGHT. 850MB TEMPS
WILL DROP TO ROUGHLY -16C BEHIND A THIRD SHORTWAVE DIVING THROUGH
THE CENTRAL GREAT LAKES AROUND 06Z. NEARLY IDEAL 340 DEGREE FETCH
DEVELOPS BUT LAKE INDUCED CONVECTION WILL BE BATTLING INCREASING DRY
AIR ENTRAINMENT AND A STRENGTHENING SUBSIDENCE INVERSION. CONVECTIVE
DEPTHS ARE ONLY AROUND 5 KFT AND DROP EVEN LOWER BY FRIDAY MORNING.
ON THE OTHER HAND...MUCH OF THE LAKE EFFECT CLOUD LAYER WILL BE IN
THE PREFERRED -12 TO -18C DENDRITIC GROWTH ZONE (ESPECIALLY BY LATE
THURSDAY NIGHT) AND BOTH NAM AND GFS BUFR SOUNDINGS SHOW GOOD
SUPERSATURATION WITH RESPECT TO ICE IN THAT LAYER. NOT EXPECTING ANY
SIGNIFICANT ACCUMULATIONS BUT AN INCH OR TWO IS CERTAINLY POSSIBLE
IN BERRIEN COUNTY AND HAVE RAISED POPS ACCORDINGLY. OTHER COUNTIES
MAY ALSO SEE A LIGHT DUSTING WITH STRONG BOUNDARY LAYER WINDS LIKELY
PUSHING ORPHANED BANDS PRETTY FAR INLAND.

NOW ON TO THE ELEPHANT IN THE ROOM. 00Z DETERMINISTIC GUIDANCE
TRENDED MUCH SLOWER...DEEPER...AND FURTHER NORTHWEST WITH THE
MIDLATITUDE CYCLONE SLATED TO DEVELOP OVER THE EASTERN CONUS LATE
SUNDAY. 00Z GFS IN PARTICULAR PAINTS AN OMINOUS PICTURE. HOWEVER...A
PRUDENT AND JUDICIOUS APPROACH IS DEMANDED AT THESE TIME RANGES.
CIRCUMSTANCES THAT CONSPIRE TO PRODUCE STORM DEPICTED IN THE 00Z GFS
ARE COMPLICATED TO SAY THE LEAST...INVOLVING THE INTERACTION OF
SOUTHWEST CONUS CUTOFF LOW AND TWO DISTINCT NORTHERN STREAM
SHORTWAVES THAT ARE SHOWN TO PHASE AND PRODUCE A STRONG/NEGATIVELY
TILTED TROUGH OVER THE OHIO VALLEY. SHORTWAVES IN QUESTION HAVE NOT
EVEN DEVELOPED YET MUCH LESS BEEN SAMPLED. FURTHERMORE...ENSEMBLE
MEMBERS STILL SHOW A HIGH DEGREE OF SPREAD AND ECMWF DEPICTS A LESS
ROBUST CYCLONE. RUN TO RUN VARIABILITY HAS ALSO BEEN VERY HIGH FOR
THIS TIME RANGE. ALL OF THIS IS TO SAY THAT FORECAST CONFIDENCE IS
VERY LOW AT THIS POINT...MUCH LOWER THAN EVEN A TYPICAL DAY5
FORECAST. CERTAINLY THE CHANCES FOR PRECIP ON SUNDAY ARE INCREASING
AND THE NEW FORECAST REFLECTS THAT BUT DETAILS REGARDING AMOUNTS AND
TYPES ARE VERY MUCH IN FLUX. STAY TUNED TO THE LATEST FORECASTS OVER
THE COMING DAYS AS DETAILS ARE ALMOST CERTAIN TO CHANGE.

STILL EXPECTING A BLAST OF MUCH COLDER AIR BEHIND THIS SYSTEM EARLY
NEXT WEEK. HIGHS WILL LIKELY REMAIN IN THE TEENS WITH OVERNIGHT LOWS
POTENTIALLY IN THE NEGATIVE SINGLE DIGITS. A BRIEF SHOT OF LAKE
EFFECT SNOW IS ALSO POSSIBLE IN THE COLD WAKE OF EXITING CYCLONE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1213 PM EST WED JAN 28 2015

VFR WITH A GRADUAL INCREASE IN SOUTHERLY WINDS AND MID-HIGH LEVEL
CLOUDS CAN BE EXPECTED THIS AFTERNOON AS WARM ADVECTION COMMENCES.
MOISTURE CHANNEL WITHIN RAMPING LOW LEVEL JET WILL DRIFT EAST OVER
NORTHERN INDIANA LATER TONIGHT INTO EARLY THURSDAY MORNING IN
ADVANCE OF AN APPROACHING MID LEVEL DISTURBANCE AND ELONGATED SFC
TROUGH. THE RESULT WILL BE DETERIORATING FLIGHT CONDITIONS AND
INCREASING CHANCES FOR RAIN SHOWERS (FREEZING RAIN POSSIBLE AT
ONSET) DURING THIS TIME.

&&

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

$$

SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...AGD
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 281152
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
652 AM EST WED JAN 28 2015

.SYNOPSIS...
ISSUED AT 401 AM EST WED JAN 28 2015

CLOUDS WILL INCREASE TODAY AS A RIDGE OF HIGH PRESSURE SHIFTS OFF TO
THE EAST. AN UPPER LEVEL DISTURBANCE ACROSS THE ROCKIES WILL TRACK
INTO THE GREAT LAKES AND OHIO VALLEY REGIONS TONIGHT BRINGING A
WINTRY MIX LATE TONIGHT INTO THURSDAY. SOME MINOR ICE AND SNOW
ACCUMULATIONS ARE POSSIBLE...PARTICULARLY ACROSS FAR NORTHERN
INDIANA...MUCH OF LOWER MICHIGAN...AND NORTHWEST OHIO. HIGH
TEMPERATURES TODAY WILL RANGE FROM THE UPPER 30S ACROSS NORTHEAST
ILLINOIS TO THE UPPER 20S ACROSS NORTHWEST OHIO AND SOUTHEAST LOWER
MICHIGAN. STEADY OR SLOWLY RISING TEMPERATURES ARE EXPECTED THROUGH
MUCH OF TONIGHT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM EST WED JAN 28 2015

AFTER CONTINUED QUIET WEATHER CONDITIONS TODAY...ATTENTION FOR
TONIGHT WILL TURN TO NEXT SYSTEM THAT COULD BRING A WINTRY MIX TO
THE AREA INTO THURSDAY.

LARGE SCALE SUBSIDENCE CONTINUES EARLY THIS MORNING AS UPSTREAM
UPPER LEVEL RIDGE AXIS BEGINS TO SHIFT EASTWARD ACROSS THE SOUTHERN
GREAT LAKES TODAY. SOUTHERLY FLOW WILL INCREASE TOADY AS LOW LEVEL
ANTICYCLONE SHIFTS EASTWARD...WITH MAINLY JUST AN INCREASE IN MID
AND HIGH LEVEL CLOUDINESS THROUGH THE DAY AS MID LEVEL WAA
STRENGTHENS MORE SUBSTANTIALLY LATE THIS AFTERNOON. DESPITE
STRENGTHENING LOW LEVEL WAA LATER...A VERY STRONG LOW LEVEL
INVERSION WILL LIMIT AFTERNOON TEMPS...ESPECIALLY CONSIDERING
THICKENING MID LEVEL CLOUDS LATER THIS AFTERNOON. PREVIOUS
FORECASTED MAX TEMPS FROM LOWER TO MID 30S WEST...TO UPPER 20S
EAST...STILL APPEAR REASONABLE.

A FAIRLY ROBUST UPPER LEVEL PV ANOMALY APPROACHING THE ROCKIES
THIS MORNING WILL REACH THE SOUTHERN GREAT LAKES/OHIO VALLEY BY
EARLY THURSDAY MORNING. AN AXIS OF 40-50 KNOT SOUTHWESTERLY LOW
LEVEL FLOW PRECEDING THIS UPPER PV ANOMALY WILL ALLOW FOR ZONE OF
STRONG ISENTROPIC LIFT AND AN AXIS OF LOW/MID LEVEL MOISTURE
CONVERGENCE WORKING FROM WEST TO EAST ACROSS THE AREA THIS EVENING
INTO THE EARLY PORTIONS OF THE OVERNIGHT. DIFFERENTIAL WARM
ADVECTION WILL ALSO ALLOW PLUME OF FAIRLY STEEP MID LEVEL LAPSE
RATES TO OVERSPREAD THE AREA DURING THE EVENING HOURS. WHILE UPPER
FORCING WILL STILL LAG TO THE WEST FOR MUCH OF THE NIGHT...NAM/GFS
DO DEPICT STRENGTHENING 850-700 HPA QVEC CONVG SIGNAL OVERSPREADING
AREA THIS EVENING...WHICH WILL BE FOLLOWED BY PERIOD OF MORE
PRONOUNCED UPPER FORCING LATE TONIGHT INTO EARLY THURSDAY.

PTYPE QUESTIONS STILL ARE THE MAIN CONCERN WITH THIS SYSTEM AS
SUBSTANTIAL LOW LEVEL WARM LAYER ADVECTING INTO THE AREA AND AN
INITIALLY DRY LOW/MID LEVEL AIR MASS (EVAPORATIVE COOLING EFFECTS)
WILL MAKE FOR CHALLENGING FORECAST. DID MAINTAIN SOME LOW TO MID
RANGE CHANCE POPS LATE EVENING INTO THE EARLY PORTION OF OVERNIGHT
GIVEN AXIS OF STRONG LOW/MID LEVEL THETAE ADVECTION AND STEEPENING
MID LEVEL LAPSE RATES...WITH SOME LIGHT FREEZING RAIN POSSIBLE
ESPECIALLY AT PRECIP ONSET. IT DOES APPEAR AS THOUGH PRECIP ACROSS
THE WEST SHOULD TRANSITION TO LIQUID AS PRIMARY LOW LEVEL MOISTURE
AXIS SHIFTS INTO THE AREA ALONG WITH NON-DIURNAL TEMP CURVE AND
TEMPS RISING INTO THE MID 30S. ACROSS THE FAR NORTH AND
PARTICULARLY THE NORTHEAST PORTIONS OF THE CWA WHERE A WEAKER WARM
LAYER IS EXPECTED...MIXED PRECIP IN THE FORM OF LIGHT FREEZING
RAIN/SLEET/SNOW MAY BE MORE OF AN ISSUE THROUGH EARLY THURSDAY
MORNING. SOME LIGHT ICE ACCUMULATION IS POSSIBLE MAINLY NORTH OF
ROUTE 30...WITH PERHAPS BEST CHANCE OF MEASURABLE ICE ACCUMULATION
ACROSS EXTREME NORTHEAST INDIANA INTO PORTIONS OF SOUTH CENTRAL
LOWER MICHIGAN AND NORTHWEST OHIO. CONFIDENCE IN MIXED PRECIP
DURATION/LOCATION A BIT TOO LOW FOR ANY HEADLINES AT THIS TIME BUT
WILL NEED TO MONITOR THIS CLOSELY DUE TO TIMING WITH THURSDAY
MORNING COMMUTE. THE POSSIBILITY DOES EXIST THAT AN ADVISORY WILL
BE NEEDED FOR THIS PERIOD FOR PORTIONS OF THE AREA.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 401 AM EST WED JAN 28 2015

ACTIVE LONG TERM PERIOD WITH NUMEROUS ISSUES TO DISCUSS. THURSDAY`S
WINTRY MIX AND POTENTIAL SUNDAY STORM ARE THE PRIMARY ITEMS OF NOTE
BUT THERE WILL BE INTERMEDIATE PERIODS OF LAKE EFFECT SNOW AS WELL
AND AT LEAST A BRIEF RETURN TO MUCH COLDER TEMPS EARLY NEXT WEEK.

PRECIP TYPES FOR THURSDAY STILL APPEAR VERY MESSY. CONTINUED WARM
AND MOIST AIR ADVECTION WITH STRONG SOUTHERLY WINDS AT THE SURFACE
WILL PUSH WET BULB TEMPS ABOVE FREEZING BY THURSDAY MORNING.
FREEZING RAIN SHOULD TRANSITION TO JUST RAIN BY 12Z THURSDAY IN ALL
BUT OUR FAR NORTHEAST COUNTIES WHERE IT MAY PERSIST FOR AN HOUR OR
TWO LONGER. HOWEVER...ARRIVAL OF SECONDARY NORTHERN STREAM VORT MAX
WILL DO TWO THINGS. ONE...INCREASE COVERAGE OF MEASURABLE PRECIP IN
OUR CWA FOR THE MIDDAY PERIOD WITH AN ADDED BUMP OF CVA-FORCED
ASCENT IN A VERY MOIST ENVIRONMENT. AND TWO...ALLOW COLDER AIR TO
FILTER BACK INTO THE AREA BEHIND SURFACE LOW TRACKING EASTWARD. THIS
WILL FORCE A CHANGEOVER TO SNOW FROM NORTH TO SOUTH DURING THE
AFTERNOON WITH A PERIOD OF SLEET ALSO POSSIBLE DURING THE
TRANSITION. EXPECTING LITTLE IF ANY ACCUMULATION THOUGH. TROWAL AXIS
AND BEST MIDLEVEL CVA BYPASS US TO THE NORTH AND WARM/WET GROUND
WILL PREVENT MOST OF WHAT DOES FALL FROM ACCUMULATING. THINK A FEW
TENTHS AT BEST FOR MOST AREAS WITH UP TO AN INCH POSSIBLE IN OUR FAR
NORTHEAST COUNTIES.

SYNOPTICALLY DRIVEN SNOW WILL EXIT BY THURSDAY EVENING BUT LAKE
EFFECT WILL LIKELY CRANK UP TO SOME DEGREE OVERNIGHT. 850MB TEMPS
WILL DROP TO ROUGHLY -16C BEHIND A THIRD SHORTWAVE DIVING THROUGH
THE CENTRAL GREAT LAKES AROUND 06Z. NEARLY IDEAL 340 DEGREE FETCH
DEVELOPS BUT LAKE INDUCED CONVECTION WILL BE BATTLING INCREASING DRY
AIR ENTRAINMENT AND A STRENGTHENING SUBSIDENCE INVERSION. CONVECTIVE
DEPTHS ARE ONLY AROUND 5 KFT AND DROP EVEN LOWER BY FRIDAY MORNING.
ON THE OTHER HAND...MUCH OF THE LAKE EFFECT CLOUD LAYER WILL BE IN
THE PREFERRED -12 TO -18C DENDRITIC GROWTH ZONE (ESPECIALLY BY LATE
THURSDAY NIGHT) AND BOTH NAM AND GFS BUFR SOUNDINGS SHOW GOOD
SUPERSATURATION WITH RESPECT TO ICE IN THAT LAYER. NOT EXPECTING ANY
SIGNIFICANT ACCUMULATIONS BUT AN INCH OR TWO IS CERTAINLY POSSIBLE
IN BERRIEN COUNTY AND HAVE RAISED POPS ACCORDINGLY. OTHER COUNTIES
MAY ALSO SEE A LIGHT DUSTING WITH STRONG BOUNDARY LAYER WINDS LIKELY
PUSHING ORPHANED BANDS PRETTY FAR INLAND.

NOW ON TO THE ELEPHANT IN THE ROOM. 00Z DETERMINISTIC GUIDANCE
TRENDED MUCH SLOWER...DEEPER...AND FURTHER NORTHWEST WITH THE
MIDLATITUDE CYCLONE SLATED TO DEVELOP OVER THE EASTERN CONUS LATE
SUNDAY. 00Z GFS IN PARTICULAR PAINTS AN OMINOUS PICTURE. HOWEVER...A
PRUDENT AND JUDICIOUS APPROACH IS DEMANDED AT THESE TIME RANGES.
CIRCUMSTANCES THAT CONSPIRE TO PRODUCE STORM DEPICTED IN THE 00Z GFS
ARE COMPLICATED TO SAY THE LEAST...INVOLVING THE INTERACTION OF
SOUTHWEST CONUS CUTOFF LOW AND TWO DISTINCT NORTHERN STREAM
SHORTWAVES THAT ARE SHOWN TO PHASE AND PRODUCE A STRONG/NEGATIVELY
TILTED TROUGH OVER THE OHIO VALLEY. SHORTWAVES IN QUESTION HAVE NOT
EVEN DEVELOPED YET MUCH LESS BEEN SAMPLED. FURTHERMORE...ENSEMBLE
MEMBERS STILL SHOW A HIGH DEGREE OF SPREAD AND ECMWF DEPICTS A LESS
ROBUST CYCLONE. RUN TO RUN VARIABILITY HAS ALSO BEEN VERY HIGH FOR
THIS TIME RANGE. ALL OF THIS IS TO SAY THAT FORECAST CONFIDENCE IS
VERY LOW AT THIS POINT...MUCH LOWER THAN EVEN A TYPICAL DAY5
FORECAST. CERTAINLY THE CHANCES FOR PRECIP ON SUNDAY ARE INCREASING
AND THE NEW FORECAST REFLECTS THAT BUT DETAILS REGARDING AMOUNTS AND
TYPES ARE VERY MUCH IN FLUX. STAY TUNED TO THE LATEST FORECASTS OVER
THE COMING DAYS AS DETAILS ARE ALMOST CERTAIN TO CHANGE.

STILL EXPECTING A BLAST OF MUCH COLDER AIR BEHIND THIS SYSTEM EARLY
NEXT WEEK. HIGHS WILL LIKELY REMAIN IN THE TEENS WITH OVERNIGHT LOWS
POTENTIALLY IN THE NEGATIVE SINGLE DIGITS. A BRIEF SHOT OF LAKE
EFFECT SNOW IS ALSO POSSIBLE IN THE COLD WAKE OF EXITING CYCLONE.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 650 AM EST WED JAN 28 2015

LOW LEVEL ANTICYCLONE ACROSS THE REGION WILL DEPART TO THE EAST
TODAY RESULTING IN INCREASING SOUTHERLY WINDS LATE THIS AFTERNOON
INTO THIS EVENING. STRONG LOW LEVEL MOISTURE TRANSPORT IS EXPECTED
FROM WEST TO EAST ACROSS NORTHERN INDIANA FROM LATE THIS EVENING
INTO EARLY THURSDAY MORNING IN ADVANCE OF AN UPPER LEVEL
DISTURBANCE EJECTING OUT OF THE ROCKIES. THIS WILL SUPPORT
INCREASING CHANCES OF PRECIPITATION LATE TONIGHT INTO THURSDAY.
HAVE ADDED A MENTION OF LLWS FOR LATE TONIGHT IN ASSOCIATION WITH
SOUTH/SOUTHWESTERLY LOW LEVEL JET IN ADVANCE OF THIS FEATURE. THIS
LOW LEVEL JET WILL ADVECT A WARM LAYER ACROSS NORTHERN INDIANA
THAT WILL PROVIDE AT LEAST A POTENTIAL OF SOME FREEZING RAIN
MAINLY IN THE 05Z-09Z TIMEFRAME. ROBUST LOW LEVEL MOISTURE
ADVECTION SHOULD TEND TO SUPPORT MAINLY LIQUID PRECIP AT TERMINALS
TOWARD THE END OF THE FORECAST VALID PERIOD.

&&

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

$$

SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...AGD
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 281152
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
652 AM EST WED JAN 28 2015

.SYNOPSIS...
ISSUED AT 401 AM EST WED JAN 28 2015

CLOUDS WILL INCREASE TODAY AS A RIDGE OF HIGH PRESSURE SHIFTS OFF TO
THE EAST. AN UPPER LEVEL DISTURBANCE ACROSS THE ROCKIES WILL TRACK
INTO THE GREAT LAKES AND OHIO VALLEY REGIONS TONIGHT BRINGING A
WINTRY MIX LATE TONIGHT INTO THURSDAY. SOME MINOR ICE AND SNOW
ACCUMULATIONS ARE POSSIBLE...PARTICULARLY ACROSS FAR NORTHERN
INDIANA...MUCH OF LOWER MICHIGAN...AND NORTHWEST OHIO. HIGH
TEMPERATURES TODAY WILL RANGE FROM THE UPPER 30S ACROSS NORTHEAST
ILLINOIS TO THE UPPER 20S ACROSS NORTHWEST OHIO AND SOUTHEAST LOWER
MICHIGAN. STEADY OR SLOWLY RISING TEMPERATURES ARE EXPECTED THROUGH
MUCH OF TONIGHT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM EST WED JAN 28 2015

AFTER CONTINUED QUIET WEATHER CONDITIONS TODAY...ATTENTION FOR
TONIGHT WILL TURN TO NEXT SYSTEM THAT COULD BRING A WINTRY MIX TO
THE AREA INTO THURSDAY.

LARGE SCALE SUBSIDENCE CONTINUES EARLY THIS MORNING AS UPSTREAM
UPPER LEVEL RIDGE AXIS BEGINS TO SHIFT EASTWARD ACROSS THE SOUTHERN
GREAT LAKES TODAY. SOUTHERLY FLOW WILL INCREASE TOADY AS LOW LEVEL
ANTICYCLONE SHIFTS EASTWARD...WITH MAINLY JUST AN INCREASE IN MID
AND HIGH LEVEL CLOUDINESS THROUGH THE DAY AS MID LEVEL WAA
STRENGTHENS MORE SUBSTANTIALLY LATE THIS AFTERNOON. DESPITE
STRENGTHENING LOW LEVEL WAA LATER...A VERY STRONG LOW LEVEL
INVERSION WILL LIMIT AFTERNOON TEMPS...ESPECIALLY CONSIDERING
THICKENING MID LEVEL CLOUDS LATER THIS AFTERNOON. PREVIOUS
FORECASTED MAX TEMPS FROM LOWER TO MID 30S WEST...TO UPPER 20S
EAST...STILL APPEAR REASONABLE.

A FAIRLY ROBUST UPPER LEVEL PV ANOMALY APPROACHING THE ROCKIES
THIS MORNING WILL REACH THE SOUTHERN GREAT LAKES/OHIO VALLEY BY
EARLY THURSDAY MORNING. AN AXIS OF 40-50 KNOT SOUTHWESTERLY LOW
LEVEL FLOW PRECEDING THIS UPPER PV ANOMALY WILL ALLOW FOR ZONE OF
STRONG ISENTROPIC LIFT AND AN AXIS OF LOW/MID LEVEL MOISTURE
CONVERGENCE WORKING FROM WEST TO EAST ACROSS THE AREA THIS EVENING
INTO THE EARLY PORTIONS OF THE OVERNIGHT. DIFFERENTIAL WARM
ADVECTION WILL ALSO ALLOW PLUME OF FAIRLY STEEP MID LEVEL LAPSE
RATES TO OVERSPREAD THE AREA DURING THE EVENING HOURS. WHILE UPPER
FORCING WILL STILL LAG TO THE WEST FOR MUCH OF THE NIGHT...NAM/GFS
DO DEPICT STRENGTHENING 850-700 HPA QVEC CONVG SIGNAL OVERSPREADING
AREA THIS EVENING...WHICH WILL BE FOLLOWED BY PERIOD OF MORE
PRONOUNCED UPPER FORCING LATE TONIGHT INTO EARLY THURSDAY.

PTYPE QUESTIONS STILL ARE THE MAIN CONCERN WITH THIS SYSTEM AS
SUBSTANTIAL LOW LEVEL WARM LAYER ADVECTING INTO THE AREA AND AN
INITIALLY DRY LOW/MID LEVEL AIR MASS (EVAPORATIVE COOLING EFFECTS)
WILL MAKE FOR CHALLENGING FORECAST. DID MAINTAIN SOME LOW TO MID
RANGE CHANCE POPS LATE EVENING INTO THE EARLY PORTION OF OVERNIGHT
GIVEN AXIS OF STRONG LOW/MID LEVEL THETAE ADVECTION AND STEEPENING
MID LEVEL LAPSE RATES...WITH SOME LIGHT FREEZING RAIN POSSIBLE
ESPECIALLY AT PRECIP ONSET. IT DOES APPEAR AS THOUGH PRECIP ACROSS
THE WEST SHOULD TRANSITION TO LIQUID AS PRIMARY LOW LEVEL MOISTURE
AXIS SHIFTS INTO THE AREA ALONG WITH NON-DIURNAL TEMP CURVE AND
TEMPS RISING INTO THE MID 30S. ACROSS THE FAR NORTH AND
PARTICULARLY THE NORTHEAST PORTIONS OF THE CWA WHERE A WEAKER WARM
LAYER IS EXPECTED...MIXED PRECIP IN THE FORM OF LIGHT FREEZING
RAIN/SLEET/SNOW MAY BE MORE OF AN ISSUE THROUGH EARLY THURSDAY
MORNING. SOME LIGHT ICE ACCUMULATION IS POSSIBLE MAINLY NORTH OF
ROUTE 30...WITH PERHAPS BEST CHANCE OF MEASURABLE ICE ACCUMULATION
ACROSS EXTREME NORTHEAST INDIANA INTO PORTIONS OF SOUTH CENTRAL
LOWER MICHIGAN AND NORTHWEST OHIO. CONFIDENCE IN MIXED PRECIP
DURATION/LOCATION A BIT TOO LOW FOR ANY HEADLINES AT THIS TIME BUT
WILL NEED TO MONITOR THIS CLOSELY DUE TO TIMING WITH THURSDAY
MORNING COMMUTE. THE POSSIBILITY DOES EXIST THAT AN ADVISORY WILL
BE NEEDED FOR THIS PERIOD FOR PORTIONS OF THE AREA.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 401 AM EST WED JAN 28 2015

ACTIVE LONG TERM PERIOD WITH NUMEROUS ISSUES TO DISCUSS. THURSDAY`S
WINTRY MIX AND POTENTIAL SUNDAY STORM ARE THE PRIMARY ITEMS OF NOTE
BUT THERE WILL BE INTERMEDIATE PERIODS OF LAKE EFFECT SNOW AS WELL
AND AT LEAST A BRIEF RETURN TO MUCH COLDER TEMPS EARLY NEXT WEEK.

PRECIP TYPES FOR THURSDAY STILL APPEAR VERY MESSY. CONTINUED WARM
AND MOIST AIR ADVECTION WITH STRONG SOUTHERLY WINDS AT THE SURFACE
WILL PUSH WET BULB TEMPS ABOVE FREEZING BY THURSDAY MORNING.
FREEZING RAIN SHOULD TRANSITION TO JUST RAIN BY 12Z THURSDAY IN ALL
BUT OUR FAR NORTHEAST COUNTIES WHERE IT MAY PERSIST FOR AN HOUR OR
TWO LONGER. HOWEVER...ARRIVAL OF SECONDARY NORTHERN STREAM VORT MAX
WILL DO TWO THINGS. ONE...INCREASE COVERAGE OF MEASURABLE PRECIP IN
OUR CWA FOR THE MIDDAY PERIOD WITH AN ADDED BUMP OF CVA-FORCED
ASCENT IN A VERY MOIST ENVIRONMENT. AND TWO...ALLOW COLDER AIR TO
FILTER BACK INTO THE AREA BEHIND SURFACE LOW TRACKING EASTWARD. THIS
WILL FORCE A CHANGEOVER TO SNOW FROM NORTH TO SOUTH DURING THE
AFTERNOON WITH A PERIOD OF SLEET ALSO POSSIBLE DURING THE
TRANSITION. EXPECTING LITTLE IF ANY ACCUMULATION THOUGH. TROWAL AXIS
AND BEST MIDLEVEL CVA BYPASS US TO THE NORTH AND WARM/WET GROUND
WILL PREVENT MOST OF WHAT DOES FALL FROM ACCUMULATING. THINK A FEW
TENTHS AT BEST FOR MOST AREAS WITH UP TO AN INCH POSSIBLE IN OUR FAR
NORTHEAST COUNTIES.

SYNOPTICALLY DRIVEN SNOW WILL EXIT BY THURSDAY EVENING BUT LAKE
EFFECT WILL LIKELY CRANK UP TO SOME DEGREE OVERNIGHT. 850MB TEMPS
WILL DROP TO ROUGHLY -16C BEHIND A THIRD SHORTWAVE DIVING THROUGH
THE CENTRAL GREAT LAKES AROUND 06Z. NEARLY IDEAL 340 DEGREE FETCH
DEVELOPS BUT LAKE INDUCED CONVECTION WILL BE BATTLING INCREASING DRY
AIR ENTRAINMENT AND A STRENGTHENING SUBSIDENCE INVERSION. CONVECTIVE
DEPTHS ARE ONLY AROUND 5 KFT AND DROP EVEN LOWER BY FRIDAY MORNING.
ON THE OTHER HAND...MUCH OF THE LAKE EFFECT CLOUD LAYER WILL BE IN
THE PREFERRED -12 TO -18C DENDRITIC GROWTH ZONE (ESPECIALLY BY LATE
THURSDAY NIGHT) AND BOTH NAM AND GFS BUFR SOUNDINGS SHOW GOOD
SUPERSATURATION WITH RESPECT TO ICE IN THAT LAYER. NOT EXPECTING ANY
SIGNIFICANT ACCUMULATIONS BUT AN INCH OR TWO IS CERTAINLY POSSIBLE
IN BERRIEN COUNTY AND HAVE RAISED POPS ACCORDINGLY. OTHER COUNTIES
MAY ALSO SEE A LIGHT DUSTING WITH STRONG BOUNDARY LAYER WINDS LIKELY
PUSHING ORPHANED BANDS PRETTY FAR INLAND.

NOW ON TO THE ELEPHANT IN THE ROOM. 00Z DETERMINISTIC GUIDANCE
TRENDED MUCH SLOWER...DEEPER...AND FURTHER NORTHWEST WITH THE
MIDLATITUDE CYCLONE SLATED TO DEVELOP OVER THE EASTERN CONUS LATE
SUNDAY. 00Z GFS IN PARTICULAR PAINTS AN OMINOUS PICTURE. HOWEVER...A
PRUDENT AND JUDICIOUS APPROACH IS DEMANDED AT THESE TIME RANGES.
CIRCUMSTANCES THAT CONSPIRE TO PRODUCE STORM DEPICTED IN THE 00Z GFS
ARE COMPLICATED TO SAY THE LEAST...INVOLVING THE INTERACTION OF
SOUTHWEST CONUS CUTOFF LOW AND TWO DISTINCT NORTHERN STREAM
SHORTWAVES THAT ARE SHOWN TO PHASE AND PRODUCE A STRONG/NEGATIVELY
TILTED TROUGH OVER THE OHIO VALLEY. SHORTWAVES IN QUESTION HAVE NOT
EVEN DEVELOPED YET MUCH LESS BEEN SAMPLED. FURTHERMORE...ENSEMBLE
MEMBERS STILL SHOW A HIGH DEGREE OF SPREAD AND ECMWF DEPICTS A LESS
ROBUST CYCLONE. RUN TO RUN VARIABILITY HAS ALSO BEEN VERY HIGH FOR
THIS TIME RANGE. ALL OF THIS IS TO SAY THAT FORECAST CONFIDENCE IS
VERY LOW AT THIS POINT...MUCH LOWER THAN EVEN A TYPICAL DAY5
FORECAST. CERTAINLY THE CHANCES FOR PRECIP ON SUNDAY ARE INCREASING
AND THE NEW FORECAST REFLECTS THAT BUT DETAILS REGARDING AMOUNTS AND
TYPES ARE VERY MUCH IN FLUX. STAY TUNED TO THE LATEST FORECASTS OVER
THE COMING DAYS AS DETAILS ARE ALMOST CERTAIN TO CHANGE.

STILL EXPECTING A BLAST OF MUCH COLDER AIR BEHIND THIS SYSTEM EARLY
NEXT WEEK. HIGHS WILL LIKELY REMAIN IN THE TEENS WITH OVERNIGHT LOWS
POTENTIALLY IN THE NEGATIVE SINGLE DIGITS. A BRIEF SHOT OF LAKE
EFFECT SNOW IS ALSO POSSIBLE IN THE COLD WAKE OF EXITING CYCLONE.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 650 AM EST WED JAN 28 2015

LOW LEVEL ANTICYCLONE ACROSS THE REGION WILL DEPART TO THE EAST
TODAY RESULTING IN INCREASING SOUTHERLY WINDS LATE THIS AFTERNOON
INTO THIS EVENING. STRONG LOW LEVEL MOISTURE TRANSPORT IS EXPECTED
FROM WEST TO EAST ACROSS NORTHERN INDIANA FROM LATE THIS EVENING
INTO EARLY THURSDAY MORNING IN ADVANCE OF AN UPPER LEVEL
DISTURBANCE EJECTING OUT OF THE ROCKIES. THIS WILL SUPPORT
INCREASING CHANCES OF PRECIPITATION LATE TONIGHT INTO THURSDAY.
HAVE ADDED A MENTION OF LLWS FOR LATE TONIGHT IN ASSOCIATION WITH
SOUTH/SOUTHWESTERLY LOW LEVEL JET IN ADVANCE OF THIS FEATURE. THIS
LOW LEVEL JET WILL ADVECT A WARM LAYER ACROSS NORTHERN INDIANA
THAT WILL PROVIDE AT LEAST A POTENTIAL OF SOME FREEZING RAIN
MAINLY IN THE 05Z-09Z TIMEFRAME. ROBUST LOW LEVEL MOISTURE
ADVECTION SHOULD TEND TO SUPPORT MAINLY LIQUID PRECIP AT TERMINALS
TOWARD THE END OF THE FORECAST VALID PERIOD.

&&

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

$$

SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...AGD
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 280906
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
406 AM EST WED JAN 28 2015

.SYNOPSIS...
ISSUED AT 401 AM EST WED JAN 28 2015

CLOUDS WILL INCREASE TODAY AS A RIDGE OF HIGH PRESSURE SHIFTS OFF TO
THE EAST. AN UPPER LEVEL DISTURBANCE ACROSS THE ROCKIES WILL TRACK
INTO THE GREAT LAKES AND OHIO VALLEY REGIONS TONIGHT BRINGING A
WINTRY MIX LATE TONIGHT INTO THURSDAY. SOME MINOR ICE AND SNOW
ACCUMULATIONS ARE POSSIBLE...PARTICULARLY ACROSS FAR NORTHERN
INDIANA...MUCH OF LOWER MICHIGAN...AND NORTHWEST OHIO. HIGH
TEMPERATURES TODAY WILL RANGE FROM THE UPPER 30S ACROSS NORTHEAST
ILLINOIS TO THE UPPER 20S ACROSS NORTHWEST OHIO AND SOUTHEAST LOWER
MICHIGAN. STEADY OR SLOWLY RISING TEMPERATURES ARE EXPECTED THROUGH
MUCH OF TONIGHT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM EST WED JAN 28 2015

AFTER CONTINUED QUIET WEATHER CONDITIONS TODAY...ATTENTION FOR
TONIGHT WILL TURN TO NEXT SYSTEM THAT COULD BRING A WINTRY MIX TO
THE AREA INTO THURSDAY.

LARGE SCALE SUBSIDENCE CONTINUES EARLY THIS MORNING AS UPSTREAM
UPPER LEVEL RIDGE AXIS BEGINS TO SHIFT EASTWARD ACROSS THE SOUTHERN
GREAT LAKES TODAY. SOUTHERLY FLOW WILL INCREASE TOADY AS LOW LEVEL
ANTICYCLONE SHIFTS EASTWARD...WITH MAINLY JUST AN INCREASE IN MID
AND HIGH LEVEL CLOUDINESS THROUGH THE DAY AS MID LEVEL WAA
STRENGTHENS MORE SUBSTANTIALLY LATE THIS AFTERNOON. DESPITE
STRENGTHENING LOW LEVEL WAA LATER...A VERY STRONG LOW LEVEL
INVERSION WILL LIMIT AFTERNOON TEMPS...ESPECIALLY CONSIDERING
THICKENING MID LEVEL CLOUDS LATER THIS AFTERNOON. PREVIOUS
FORECASTED MAX TEMPS FROM LOWER TO MID 30S WEST...TO UPPER 20S
EAST...STILL APPEAR REASONABLE.

A FAIRLY ROBUST UPPER LEVEL PV ANOMALY APPROACHING THE ROCKIES
THIS MORNING WILL REACH THE SOUTHERN GREAT LAKES/OHIO VALLEY BY
EARLY THURSDAY MORNING. AN AXIS OF 40-50 KNOT SOUTHWESTERLY LOW
LEVEL FLOW PRECEDING THIS UPPER PV ANOMALY WILL ALLOW FOR ZONE OF
STRONG ISENTROPIC LIFT AND AN AXIS OF LOW/MID LEVEL MOISTURE
CONVERGENCE WORKING FROM WEST TO EAST ACROSS THE AREA THIS EVENING
INTO THE EARLY PORTIONS OF THE OVERNIGHT. DIFFERENTIAL WARM
ADVECTION WILL ALSO ALLOW PLUME OF FAIRLY STEEP MID LEVEL LAPSE
RATES TO OVERSPREAD THE AREA DURING THE EVENING HOURS. WHILE UPPER
FORCING WILL STILL LAG TO THE WEST FOR MUCH OF THE NIGHT...NAM/GFS
DO DEPICT STRENGTHENING 850-700 HPA QVEC CONVG SIGNAL OVERSPREADING
AREA THIS EVENING...WHICH WILL BE FOLLOWED BY PERIOD OF MORE
PRONOUNCED UPPER FORCING LATE TONIGHT INTO EARLY THURSDAY.

PTYPE QUESTIONS STILL ARE THE MAIN CONCERN WITH THIS SYSTEM AS
SUBSTANTIAL LOW LEVEL WARM LAYER ADVECTING INTO THE AREA AND AN
INITIALLY DRY LOW/MID LEVEL AIR MASS (EVAPORATIVE COOLING EFFECTS)
WILL MAKE FOR CHALLENGING FORECAST. DID MAINTAIN SOME LOW TO MID
RANGE CHANCE POPS LATE EVENING INTO THE EARLY PORTION OF OVERNIGHT
GIVEN AXIS OF STRONG LOW/MID LEVEL THETAE ADVECTION AND STEEPENING
MID LEVEL LAPSE RATES...WITH SOME LIGHT FREEZING RAIN POSSIBLE
ESPECIALLY AT PRECIP ONSET. IT DOES APPEAR AS THOUGH PRECIP ACROSS
THE WEST SHOULD TRANSITION TO LIQUID AS PRIMARY LOW LEVEL MOISTURE
AXIS SHIFTS INTO THE AREA ALONG WITH NON-DIURNAL TEMP CURVE AND
TEMPS RISING INTO THE MID 30S. ACROSS THE FAR NORTH AND
PARTICULARLY THE NORTHEAST PORTIONS OF THE CWA WHERE A WEAKER WARM
LAYER IS EXPECTED...MIXED PRECIP IN THE FORM OF LIGHT FREEZING
RAIN/SLEET/SNOW MAY BE MORE OF AN ISSUE THROUGH EARLY THURSDAY
MORNING. SOME LIGHT ICE ACCUMULATION IS POSSIBLE MAINLY NORTH OF
ROUTE 30...WITH PERHAPS BEST CHANCE OF MEASURABLE ICE ACCUMULATION
ACROSS EXTREME NORTHEAST INDIANA INTO PORTIONS OF SOUTH CENTRAL
LOWER MICHIGAN AND NORTHWEST OHIO. CONFIDENCE IN MIXED PRECIP
DURATION/LOCATION A BIT TOO LOW FOR ANY HEADLINES AT THIS TIME BUT
WILL NEED TO MONITOR THIS CLOSELY DUE TO TIMING WITH THURSDAY
MORNING COMMUTE. THE POSSIBILITY DOES EXIST THAT AN ADVISORY WILL
BE NEEDED FOR THIS PERIOD FOR PORTIONS OF THE AREA.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 401 AM EST WED JAN 28 2015

ACTIVE LONG TERM PERIOD WITH NUMEROUS ISSUES TO DISCUSS. THURSDAY`S
WINTRY MIX AND POTENTIAL SUNDAY STORM ARE THE PRIMARY ITEMS OF NOTE
BUT THERE WILL BE INTERMEDIATE PERIODS OF LAKE EFFECT SNOW AS WELL
AND AT LEAST A BRIEF RETURN TO MUCH COLDER TEMPS EARLY NEXT WEEK.

PRECIP TYPES FOR THURSDAY STILL APPEAR VERY MESSY. CONTINUED WARM
AND MOIST AIR ADVECTION WITH STRONG SOUTHERLY WINDS AT THE SURFACE
WILL PUSH WET BULB TEMPS ABOVE FREEZING BY THURSDAY MORNING.
FREEZING RAIN SHOULD TRANSITION TO JUST RAIN BY 12Z THURSDAY IN ALL
BUT OUR FAR NORTHEAST COUNTIES WHERE IT MAY PERSIST FOR AN HOUR OR
TWO LONGER. HOWEVER...ARRIVAL OF SECONDARY NORTHERN STREAM VORT MAX
WILL DO TWO THINGS. ONE...INCREASE COVERAGE OF MEASURABLE PRECIP IN
OUR CWA FOR THE MIDDAY PERIOD WITH AN ADDED BUMP OF CVA-FORCED
ASCENT IN A VERY MOIST ENVIRONMENT. AND TWO...ALLOW COLDER AIR TO
FILTER BACK INTO THE AREA BEHIND SURFACE LOW TRACKING EASTWARD. THIS
WILL FORCE A CHANGEOVER TO SNOW FROM NORTH TO SOUTH DURING THE
AFTERNOON WITH A PERIOD OF SLEET ALSO POSSIBLE DURING THE
TRANSITION. EXPECTING LITTLE IF ANY ACCUMULATION THOUGH. TROWAL AXIS
AND BEST MIDLEVEL CVA BYPASS US TO THE NORTH AND WARM/WET GROUND
WILL PREVENT MOST OF WHAT DOES FALL FROM ACCUMULATING. THINK A FEW
TENTHS AT BEST FOR MOST AREAS WITH UP TO AN INCH POSSIBLE IN OUR FAR
NORTHEAST COUNTIES.

SYNOPTICALLY DRIVEN SNOW WILL EXIT BY THURSDAY EVENING BUT LAKE
EFFECT WILL LIKELY CRANK UP TO SOME DEGREE OVERNIGHT. 850MB TEMPS
WILL DROP TO ROUGHLY -16C BEHIND A THIRD SHORTWAVE DIVING THROUGH
THE CENTRAL GREAT LAKES AROUND 06Z. NEARLY IDEAL 340 DEGREE FETCH
DEVELOPS BUT LAKE INDUCED CONVECTION WILL BE BATTLING INCREASING DRY
AIR ENTRAINMENT AND A STRENGTHENING SUBSIDENCE INVERSION. CONVECTIVE
DEPTHS ARE ONLY AROUND 5 KFT AND DROP EVEN LOWER BY FRIDAY MORNING.
ON THE OTHER HAND...MUCH OF THE LAKE EFFECT CLOUD LAYER WILL BE IN
THE PREFERRED -12 TO -18C DENDRITIC GROWTH ZONE (ESPECIALLY BY LATE
THURSDAY NIGHT) AND BOTH NAM AND GFS BUFR SOUNDINGS SHOW GOOD
SUPERSATURATION WITH RESPECT TO ICE IN THAT LAYER. NOT EXPECTING ANY
SIGNIFICANT ACCUMULATIONS BUT AN INCH OR TWO IS CERTAINLY POSSIBLE
IN BERRIEN COUNTY AND HAVE RAISED POPS ACCORDINGLY. OTHER COUNTIES
MAY ALSO SEE A LIGHT DUSTING WITH STRONG BOUNDARY LAYER WINDS LIKELY
PUSHING ORPHANED BANDS PRETTY FAR INLAND.

NOW ON TO THE ELEPHANT IN THE ROOM. 00Z DETERMINISTIC GUIDANCE
TRENDED MUCH SLOWER...DEEPER...AND FURTHER NORTHWEST WITH THE
MIDLATITUDE CYCLONE SLATED TO DEVELOP OVER THE EASTERN CONUS LATE
SUNDAY. 00Z GFS IN PARTICULAR PAINTS AN OMINOUS PICTURE. HOWEVER...A
PRUDENT AND JUDICIOUS APPROACH IS DEMANDED AT THESE TIME RANGES.
CIRCUMSTANCES THAT CONSPIRE TO PRODUCE STORM DEPICTED IN THE 00Z GFS
ARE COMPLICATED TO SAY THE LEAST...INVOLVING THE INTERACTION OF
SOUTHWEST CONUS CUTOFF LOW AND TWO DISTINCT NORTHERN STREAM
SHORTWAVES THAT ARE SHOWN TO PHASE AND PRODUCE A STRONG/NEGATIVELY
TILTED TROUGH OVER THE OHIO VALLEY. SHORTWAVES IN QUESTION HAVE NOT
EVEN DEVELOPED YET MUCH LESS BEEN SAMPLED. FURTHERMORE...ENSEMBLE
MEMBERS STILL SHOW A HIGH DEGREE OF SPREAD AND ECMWF DEPICTS A LESS
ROBUST CYCLONE. RUN TO RUN VARIABILITY HAS ALSO BEEN VERY HIGH FOR
THIS TIME RANGE. ALL OF THIS IS TO SAY THAT FORECAST CONFIDENCE IS
VERY LOW AT THIS POINT...MUCH LOWER THAN EVEN A TYPICAL DAY5
FORECAST. CERTAINLY THE CHANCES FOR PRECIP ON SUNDAY ARE INCREASING
AND THE NEW FORECAST REFLECTS THAT BUT DETAILS REGARDING AMOUNTS AND
TYPES ARE VERY MUCH IN FLUX. STAY TUNED TO THE LATEST FORECASTS OVER
THE COMING DAYS AS DETAILS ARE ALMOST CERTAIN TO CHANGE.

STILL EXPECTING A BLAST OF MUCH COLDER AIR BEHIND THIS SYSTEM EARLY
NEXT WEEK. HIGHS WILL LIKELY REMAIN IN THE TEENS WITH OVERNIGHT LOWS
POTENTIALLY IN THE NEGATIVE SINGLE DIGITS. A BRIEF SHOT OF LAKE
EFFECT SNOW IS ALSO POSSIBLE IN THE COLD WAKE OF EXITING CYCLONE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1251 AM EST WED JAN 28 2015

LOW LEVEL ANTICYCLONE WILL BRING CONTINUED LIGHT AND VARIABLE
WINDS THROUGH EARLY THIS MORNING. SOUTHEAST WINDS WILL DEVELOP AS
THIS HIGH PRESSURE DEPARTS TO THE EAST TODAY...WITH STRONGEST LATE
AFTERNOON GRADIENT SETTING UP ACROSS NORTHWEST INDIANA WHERE SOME
LATE AFTERNOON SOUTHEAST GUSTS INTO THE 15 TO 18 KNOT RANGE ARE
POSSIBLE. A SOUTHWESTERLY LOW LEVEL JET IN ADVANCE OF NEXT SYSTEM
LATE TONIGHT INTO EARLY THURSDAY WILL ALLOW FOR SOUTHEAST WINDS IN
THE 15G20-25 KNOT RANGE FOR TONIGHT WITH SOME INDICATIONS THAT
LLWS MAY BECOME A CONCERN MAINLY OUTSIDE OF THIS FORECAST PERIOD
IN THE 06Z-12Z TIMEFRAME EARLY THURSDAY MORNING. MID AND HIGH
LEVEL CLOUDINESS TO INCREASE TODAY...WITH DETERIORATING CIGS NOT
ANTICIPATED UNTIL AFTER THIS FORECAST VALID PERIOD. SOME LIGHT
SNOW/RAIN/FREEZING RAIN CONCERNS SHOULD ALSO HOLD OFF UNTIL MAINLY
AFTER THIS FORECAST VALID PERIOD AS NEXT SYSTEM APPROACHES...WHICH
WILL NEED TO BE ADDRESSED IN GREATER DEPTH FOR THE 12Z TAFS.

&&

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

$$

SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...AGD
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 280906
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
406 AM EST WED JAN 28 2015

.SYNOPSIS...
ISSUED AT 401 AM EST WED JAN 28 2015

CLOUDS WILL INCREASE TODAY AS A RIDGE OF HIGH PRESSURE SHIFTS OFF TO
THE EAST. AN UPPER LEVEL DISTURBANCE ACROSS THE ROCKIES WILL TRACK
INTO THE GREAT LAKES AND OHIO VALLEY REGIONS TONIGHT BRINGING A
WINTRY MIX LATE TONIGHT INTO THURSDAY. SOME MINOR ICE AND SNOW
ACCUMULATIONS ARE POSSIBLE...PARTICULARLY ACROSS FAR NORTHERN
INDIANA...MUCH OF LOWER MICHIGAN...AND NORTHWEST OHIO. HIGH
TEMPERATURES TODAY WILL RANGE FROM THE UPPER 30S ACROSS NORTHEAST
ILLINOIS TO THE UPPER 20S ACROSS NORTHWEST OHIO AND SOUTHEAST LOWER
MICHIGAN. STEADY OR SLOWLY RISING TEMPERATURES ARE EXPECTED THROUGH
MUCH OF TONIGHT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM EST WED JAN 28 2015

AFTER CONTINUED QUIET WEATHER CONDITIONS TODAY...ATTENTION FOR
TONIGHT WILL TURN TO NEXT SYSTEM THAT COULD BRING A WINTRY MIX TO
THE AREA INTO THURSDAY.

LARGE SCALE SUBSIDENCE CONTINUES EARLY THIS MORNING AS UPSTREAM
UPPER LEVEL RIDGE AXIS BEGINS TO SHIFT EASTWARD ACROSS THE SOUTHERN
GREAT LAKES TODAY. SOUTHERLY FLOW WILL INCREASE TOADY AS LOW LEVEL
ANTICYCLONE SHIFTS EASTWARD...WITH MAINLY JUST AN INCREASE IN MID
AND HIGH LEVEL CLOUDINESS THROUGH THE DAY AS MID LEVEL WAA
STRENGTHENS MORE SUBSTANTIALLY LATE THIS AFTERNOON. DESPITE
STRENGTHENING LOW LEVEL WAA LATER...A VERY STRONG LOW LEVEL
INVERSION WILL LIMIT AFTERNOON TEMPS...ESPECIALLY CONSIDERING
THICKENING MID LEVEL CLOUDS LATER THIS AFTERNOON. PREVIOUS
FORECASTED MAX TEMPS FROM LOWER TO MID 30S WEST...TO UPPER 20S
EAST...STILL APPEAR REASONABLE.

A FAIRLY ROBUST UPPER LEVEL PV ANOMALY APPROACHING THE ROCKIES
THIS MORNING WILL REACH THE SOUTHERN GREAT LAKES/OHIO VALLEY BY
EARLY THURSDAY MORNING. AN AXIS OF 40-50 KNOT SOUTHWESTERLY LOW
LEVEL FLOW PRECEDING THIS UPPER PV ANOMALY WILL ALLOW FOR ZONE OF
STRONG ISENTROPIC LIFT AND AN AXIS OF LOW/MID LEVEL MOISTURE
CONVERGENCE WORKING FROM WEST TO EAST ACROSS THE AREA THIS EVENING
INTO THE EARLY PORTIONS OF THE OVERNIGHT. DIFFERENTIAL WARM
ADVECTION WILL ALSO ALLOW PLUME OF FAIRLY STEEP MID LEVEL LAPSE
RATES TO OVERSPREAD THE AREA DURING THE EVENING HOURS. WHILE UPPER
FORCING WILL STILL LAG TO THE WEST FOR MUCH OF THE NIGHT...NAM/GFS
DO DEPICT STRENGTHENING 850-700 HPA QVEC CONVG SIGNAL OVERSPREADING
AREA THIS EVENING...WHICH WILL BE FOLLOWED BY PERIOD OF MORE
PRONOUNCED UPPER FORCING LATE TONIGHT INTO EARLY THURSDAY.

PTYPE QUESTIONS STILL ARE THE MAIN CONCERN WITH THIS SYSTEM AS
SUBSTANTIAL LOW LEVEL WARM LAYER ADVECTING INTO THE AREA AND AN
INITIALLY DRY LOW/MID LEVEL AIR MASS (EVAPORATIVE COOLING EFFECTS)
WILL MAKE FOR CHALLENGING FORECAST. DID MAINTAIN SOME LOW TO MID
RANGE CHANCE POPS LATE EVENING INTO THE EARLY PORTION OF OVERNIGHT
GIVEN AXIS OF STRONG LOW/MID LEVEL THETAE ADVECTION AND STEEPENING
MID LEVEL LAPSE RATES...WITH SOME LIGHT FREEZING RAIN POSSIBLE
ESPECIALLY AT PRECIP ONSET. IT DOES APPEAR AS THOUGH PRECIP ACROSS
THE WEST SHOULD TRANSITION TO LIQUID AS PRIMARY LOW LEVEL MOISTURE
AXIS SHIFTS INTO THE AREA ALONG WITH NON-DIURNAL TEMP CURVE AND
TEMPS RISING INTO THE MID 30S. ACROSS THE FAR NORTH AND
PARTICULARLY THE NORTHEAST PORTIONS OF THE CWA WHERE A WEAKER WARM
LAYER IS EXPECTED...MIXED PRECIP IN THE FORM OF LIGHT FREEZING
RAIN/SLEET/SNOW MAY BE MORE OF AN ISSUE THROUGH EARLY THURSDAY
MORNING. SOME LIGHT ICE ACCUMULATION IS POSSIBLE MAINLY NORTH OF
ROUTE 30...WITH PERHAPS BEST CHANCE OF MEASURABLE ICE ACCUMULATION
ACROSS EXTREME NORTHEAST INDIANA INTO PORTIONS OF SOUTH CENTRAL
LOWER MICHIGAN AND NORTHWEST OHIO. CONFIDENCE IN MIXED PRECIP
DURATION/LOCATION A BIT TOO LOW FOR ANY HEADLINES AT THIS TIME BUT
WILL NEED TO MONITOR THIS CLOSELY DUE TO TIMING WITH THURSDAY
MORNING COMMUTE. THE POSSIBILITY DOES EXIST THAT AN ADVISORY WILL
BE NEEDED FOR THIS PERIOD FOR PORTIONS OF THE AREA.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 401 AM EST WED JAN 28 2015

ACTIVE LONG TERM PERIOD WITH NUMEROUS ISSUES TO DISCUSS. THURSDAY`S
WINTRY MIX AND POTENTIAL SUNDAY STORM ARE THE PRIMARY ITEMS OF NOTE
BUT THERE WILL BE INTERMEDIATE PERIODS OF LAKE EFFECT SNOW AS WELL
AND AT LEAST A BRIEF RETURN TO MUCH COLDER TEMPS EARLY NEXT WEEK.

PRECIP TYPES FOR THURSDAY STILL APPEAR VERY MESSY. CONTINUED WARM
AND MOIST AIR ADVECTION WITH STRONG SOUTHERLY WINDS AT THE SURFACE
WILL PUSH WET BULB TEMPS ABOVE FREEZING BY THURSDAY MORNING.
FREEZING RAIN SHOULD TRANSITION TO JUST RAIN BY 12Z THURSDAY IN ALL
BUT OUR FAR NORTHEAST COUNTIES WHERE IT MAY PERSIST FOR AN HOUR OR
TWO LONGER. HOWEVER...ARRIVAL OF SECONDARY NORTHERN STREAM VORT MAX
WILL DO TWO THINGS. ONE...INCREASE COVERAGE OF MEASURABLE PRECIP IN
OUR CWA FOR THE MIDDAY PERIOD WITH AN ADDED BUMP OF CVA-FORCED
ASCENT IN A VERY MOIST ENVIRONMENT. AND TWO...ALLOW COLDER AIR TO
FILTER BACK INTO THE AREA BEHIND SURFACE LOW TRACKING EASTWARD. THIS
WILL FORCE A CHANGEOVER TO SNOW FROM NORTH TO SOUTH DURING THE
AFTERNOON WITH A PERIOD OF SLEET ALSO POSSIBLE DURING THE
TRANSITION. EXPECTING LITTLE IF ANY ACCUMULATION THOUGH. TROWAL AXIS
AND BEST MIDLEVEL CVA BYPASS US TO THE NORTH AND WARM/WET GROUND
WILL PREVENT MOST OF WHAT DOES FALL FROM ACCUMULATING. THINK A FEW
TENTHS AT BEST FOR MOST AREAS WITH UP TO AN INCH POSSIBLE IN OUR FAR
NORTHEAST COUNTIES.

SYNOPTICALLY DRIVEN SNOW WILL EXIT BY THURSDAY EVENING BUT LAKE
EFFECT WILL LIKELY CRANK UP TO SOME DEGREE OVERNIGHT. 850MB TEMPS
WILL DROP TO ROUGHLY -16C BEHIND A THIRD SHORTWAVE DIVING THROUGH
THE CENTRAL GREAT LAKES AROUND 06Z. NEARLY IDEAL 340 DEGREE FETCH
DEVELOPS BUT LAKE INDUCED CONVECTION WILL BE BATTLING INCREASING DRY
AIR ENTRAINMENT AND A STRENGTHENING SUBSIDENCE INVERSION. CONVECTIVE
DEPTHS ARE ONLY AROUND 5 KFT AND DROP EVEN LOWER BY FRIDAY MORNING.
ON THE OTHER HAND...MUCH OF THE LAKE EFFECT CLOUD LAYER WILL BE IN
THE PREFERRED -12 TO -18C DENDRITIC GROWTH ZONE (ESPECIALLY BY LATE
THURSDAY NIGHT) AND BOTH NAM AND GFS BUFR SOUNDINGS SHOW GOOD
SUPERSATURATION WITH RESPECT TO ICE IN THAT LAYER. NOT EXPECTING ANY
SIGNIFICANT ACCUMULATIONS BUT AN INCH OR TWO IS CERTAINLY POSSIBLE
IN BERRIEN COUNTY AND HAVE RAISED POPS ACCORDINGLY. OTHER COUNTIES
MAY ALSO SEE A LIGHT DUSTING WITH STRONG BOUNDARY LAYER WINDS LIKELY
PUSHING ORPHANED BANDS PRETTY FAR INLAND.

NOW ON TO THE ELEPHANT IN THE ROOM. 00Z DETERMINISTIC GUIDANCE
TRENDED MUCH SLOWER...DEEPER...AND FURTHER NORTHWEST WITH THE
MIDLATITUDE CYCLONE SLATED TO DEVELOP OVER THE EASTERN CONUS LATE
SUNDAY. 00Z GFS IN PARTICULAR PAINTS AN OMINOUS PICTURE. HOWEVER...A
PRUDENT AND JUDICIOUS APPROACH IS DEMANDED AT THESE TIME RANGES.
CIRCUMSTANCES THAT CONSPIRE TO PRODUCE STORM DEPICTED IN THE 00Z GFS
ARE COMPLICATED TO SAY THE LEAST...INVOLVING THE INTERACTION OF
SOUTHWEST CONUS CUTOFF LOW AND TWO DISTINCT NORTHERN STREAM
SHORTWAVES THAT ARE SHOWN TO PHASE AND PRODUCE A STRONG/NEGATIVELY
TILTED TROUGH OVER THE OHIO VALLEY. SHORTWAVES IN QUESTION HAVE NOT
EVEN DEVELOPED YET MUCH LESS BEEN SAMPLED. FURTHERMORE...ENSEMBLE
MEMBERS STILL SHOW A HIGH DEGREE OF SPREAD AND ECMWF DEPICTS A LESS
ROBUST CYCLONE. RUN TO RUN VARIABILITY HAS ALSO BEEN VERY HIGH FOR
THIS TIME RANGE. ALL OF THIS IS TO SAY THAT FORECAST CONFIDENCE IS
VERY LOW AT THIS POINT...MUCH LOWER THAN EVEN A TYPICAL DAY5
FORECAST. CERTAINLY THE CHANCES FOR PRECIP ON SUNDAY ARE INCREASING
AND THE NEW FORECAST REFLECTS THAT BUT DETAILS REGARDING AMOUNTS AND
TYPES ARE VERY MUCH IN FLUX. STAY TUNED TO THE LATEST FORECASTS OVER
THE COMING DAYS AS DETAILS ARE ALMOST CERTAIN TO CHANGE.

STILL EXPECTING A BLAST OF MUCH COLDER AIR BEHIND THIS SYSTEM EARLY
NEXT WEEK. HIGHS WILL LIKELY REMAIN IN THE TEENS WITH OVERNIGHT LOWS
POTENTIALLY IN THE NEGATIVE SINGLE DIGITS. A BRIEF SHOT OF LAKE
EFFECT SNOW IS ALSO POSSIBLE IN THE COLD WAKE OF EXITING CYCLONE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1251 AM EST WED JAN 28 2015

LOW LEVEL ANTICYCLONE WILL BRING CONTINUED LIGHT AND VARIABLE
WINDS THROUGH EARLY THIS MORNING. SOUTHEAST WINDS WILL DEVELOP AS
THIS HIGH PRESSURE DEPARTS TO THE EAST TODAY...WITH STRONGEST LATE
AFTERNOON GRADIENT SETTING UP ACROSS NORTHWEST INDIANA WHERE SOME
LATE AFTERNOON SOUTHEAST GUSTS INTO THE 15 TO 18 KNOT RANGE ARE
POSSIBLE. A SOUTHWESTERLY LOW LEVEL JET IN ADVANCE OF NEXT SYSTEM
LATE TONIGHT INTO EARLY THURSDAY WILL ALLOW FOR SOUTHEAST WINDS IN
THE 15G20-25 KNOT RANGE FOR TONIGHT WITH SOME INDICATIONS THAT
LLWS MAY BECOME A CONCERN MAINLY OUTSIDE OF THIS FORECAST PERIOD
IN THE 06Z-12Z TIMEFRAME EARLY THURSDAY MORNING. MID AND HIGH
LEVEL CLOUDINESS TO INCREASE TODAY...WITH DETERIORATING CIGS NOT
ANTICIPATED UNTIL AFTER THIS FORECAST VALID PERIOD. SOME LIGHT
SNOW/RAIN/FREEZING RAIN CONCERNS SHOULD ALSO HOLD OFF UNTIL MAINLY
AFTER THIS FORECAST VALID PERIOD AS NEXT SYSTEM APPROACHES...WHICH
WILL NEED TO BE ADDRESSED IN GREATER DEPTH FOR THE 12Z TAFS.

&&

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

$$

SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...AGD
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 280906
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
406 AM EST WED JAN 28 2015

.SYNOPSIS...
ISSUED AT 401 AM EST WED JAN 28 2015

CLOUDS WILL INCREASE TODAY AS A RIDGE OF HIGH PRESSURE SHIFTS OFF TO
THE EAST. AN UPPER LEVEL DISTURBANCE ACROSS THE ROCKIES WILL TRACK
INTO THE GREAT LAKES AND OHIO VALLEY REGIONS TONIGHT BRINGING A
WINTRY MIX LATE TONIGHT INTO THURSDAY. SOME MINOR ICE AND SNOW
ACCUMULATIONS ARE POSSIBLE...PARTICULARLY ACROSS FAR NORTHERN
INDIANA...MUCH OF LOWER MICHIGAN...AND NORTHWEST OHIO. HIGH
TEMPERATURES TODAY WILL RANGE FROM THE UPPER 30S ACROSS NORTHEAST
ILLINOIS TO THE UPPER 20S ACROSS NORTHWEST OHIO AND SOUTHEAST LOWER
MICHIGAN. STEADY OR SLOWLY RISING TEMPERATURES ARE EXPECTED THROUGH
MUCH OF TONIGHT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM EST WED JAN 28 2015

AFTER CONTINUED QUIET WEATHER CONDITIONS TODAY...ATTENTION FOR
TONIGHT WILL TURN TO NEXT SYSTEM THAT COULD BRING A WINTRY MIX TO
THE AREA INTO THURSDAY.

LARGE SCALE SUBSIDENCE CONTINUES EARLY THIS MORNING AS UPSTREAM
UPPER LEVEL RIDGE AXIS BEGINS TO SHIFT EASTWARD ACROSS THE SOUTHERN
GREAT LAKES TODAY. SOUTHERLY FLOW WILL INCREASE TOADY AS LOW LEVEL
ANTICYCLONE SHIFTS EASTWARD...WITH MAINLY JUST AN INCREASE IN MID
AND HIGH LEVEL CLOUDINESS THROUGH THE DAY AS MID LEVEL WAA
STRENGTHENS MORE SUBSTANTIALLY LATE THIS AFTERNOON. DESPITE
STRENGTHENING LOW LEVEL WAA LATER...A VERY STRONG LOW LEVEL
INVERSION WILL LIMIT AFTERNOON TEMPS...ESPECIALLY CONSIDERING
THICKENING MID LEVEL CLOUDS LATER THIS AFTERNOON. PREVIOUS
FORECASTED MAX TEMPS FROM LOWER TO MID 30S WEST...TO UPPER 20S
EAST...STILL APPEAR REASONABLE.

A FAIRLY ROBUST UPPER LEVEL PV ANOMALY APPROACHING THE ROCKIES
THIS MORNING WILL REACH THE SOUTHERN GREAT LAKES/OHIO VALLEY BY
EARLY THURSDAY MORNING. AN AXIS OF 40-50 KNOT SOUTHWESTERLY LOW
LEVEL FLOW PRECEDING THIS UPPER PV ANOMALY WILL ALLOW FOR ZONE OF
STRONG ISENTROPIC LIFT AND AN AXIS OF LOW/MID LEVEL MOISTURE
CONVERGENCE WORKING FROM WEST TO EAST ACROSS THE AREA THIS EVENING
INTO THE EARLY PORTIONS OF THE OVERNIGHT. DIFFERENTIAL WARM
ADVECTION WILL ALSO ALLOW PLUME OF FAIRLY STEEP MID LEVEL LAPSE
RATES TO OVERSPREAD THE AREA DURING THE EVENING HOURS. WHILE UPPER
FORCING WILL STILL LAG TO THE WEST FOR MUCH OF THE NIGHT...NAM/GFS
DO DEPICT STRENGTHENING 850-700 HPA QVEC CONVG SIGNAL OVERSPREADING
AREA THIS EVENING...WHICH WILL BE FOLLOWED BY PERIOD OF MORE
PRONOUNCED UPPER FORCING LATE TONIGHT INTO EARLY THURSDAY.

PTYPE QUESTIONS STILL ARE THE MAIN CONCERN WITH THIS SYSTEM AS
SUBSTANTIAL LOW LEVEL WARM LAYER ADVECTING INTO THE AREA AND AN
INITIALLY DRY LOW/MID LEVEL AIR MASS (EVAPORATIVE COOLING EFFECTS)
WILL MAKE FOR CHALLENGING FORECAST. DID MAINTAIN SOME LOW TO MID
RANGE CHANCE POPS LATE EVENING INTO THE EARLY PORTION OF OVERNIGHT
GIVEN AXIS OF STRONG LOW/MID LEVEL THETAE ADVECTION AND STEEPENING
MID LEVEL LAPSE RATES...WITH SOME LIGHT FREEZING RAIN POSSIBLE
ESPECIALLY AT PRECIP ONSET. IT DOES APPEAR AS THOUGH PRECIP ACROSS
THE WEST SHOULD TRANSITION TO LIQUID AS PRIMARY LOW LEVEL MOISTURE
AXIS SHIFTS INTO THE AREA ALONG WITH NON-DIURNAL TEMP CURVE AND
TEMPS RISING INTO THE MID 30S. ACROSS THE FAR NORTH AND
PARTICULARLY THE NORTHEAST PORTIONS OF THE CWA WHERE A WEAKER WARM
LAYER IS EXPECTED...MIXED PRECIP IN THE FORM OF LIGHT FREEZING
RAIN/SLEET/SNOW MAY BE MORE OF AN ISSUE THROUGH EARLY THURSDAY
MORNING. SOME LIGHT ICE ACCUMULATION IS POSSIBLE MAINLY NORTH OF
ROUTE 30...WITH PERHAPS BEST CHANCE OF MEASURABLE ICE ACCUMULATION
ACROSS EXTREME NORTHEAST INDIANA INTO PORTIONS OF SOUTH CENTRAL
LOWER MICHIGAN AND NORTHWEST OHIO. CONFIDENCE IN MIXED PRECIP
DURATION/LOCATION A BIT TOO LOW FOR ANY HEADLINES AT THIS TIME BUT
WILL NEED TO MONITOR THIS CLOSELY DUE TO TIMING WITH THURSDAY
MORNING COMMUTE. THE POSSIBILITY DOES EXIST THAT AN ADVISORY WILL
BE NEEDED FOR THIS PERIOD FOR PORTIONS OF THE AREA.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 401 AM EST WED JAN 28 2015

ACTIVE LONG TERM PERIOD WITH NUMEROUS ISSUES TO DISCUSS. THURSDAY`S
WINTRY MIX AND POTENTIAL SUNDAY STORM ARE THE PRIMARY ITEMS OF NOTE
BUT THERE WILL BE INTERMEDIATE PERIODS OF LAKE EFFECT SNOW AS WELL
AND AT LEAST A BRIEF RETURN TO MUCH COLDER TEMPS EARLY NEXT WEEK.

PRECIP TYPES FOR THURSDAY STILL APPEAR VERY MESSY. CONTINUED WARM
AND MOIST AIR ADVECTION WITH STRONG SOUTHERLY WINDS AT THE SURFACE
WILL PUSH WET BULB TEMPS ABOVE FREEZING BY THURSDAY MORNING.
FREEZING RAIN SHOULD TRANSITION TO JUST RAIN BY 12Z THURSDAY IN ALL
BUT OUR FAR NORTHEAST COUNTIES WHERE IT MAY PERSIST FOR AN HOUR OR
TWO LONGER. HOWEVER...ARRIVAL OF SECONDARY NORTHERN STREAM VORT MAX
WILL DO TWO THINGS. ONE...INCREASE COVERAGE OF MEASURABLE PRECIP IN
OUR CWA FOR THE MIDDAY PERIOD WITH AN ADDED BUMP OF CVA-FORCED
ASCENT IN A VERY MOIST ENVIRONMENT. AND TWO...ALLOW COLDER AIR TO
FILTER BACK INTO THE AREA BEHIND SURFACE LOW TRACKING EASTWARD. THIS
WILL FORCE A CHANGEOVER TO SNOW FROM NORTH TO SOUTH DURING THE
AFTERNOON WITH A PERIOD OF SLEET ALSO POSSIBLE DURING THE
TRANSITION. EXPECTING LITTLE IF ANY ACCUMULATION THOUGH. TROWAL AXIS
AND BEST MIDLEVEL CVA BYPASS US TO THE NORTH AND WARM/WET GROUND
WILL PREVENT MOST OF WHAT DOES FALL FROM ACCUMULATING. THINK A FEW
TENTHS AT BEST FOR MOST AREAS WITH UP TO AN INCH POSSIBLE IN OUR FAR
NORTHEAST COUNTIES.

SYNOPTICALLY DRIVEN SNOW WILL EXIT BY THURSDAY EVENING BUT LAKE
EFFECT WILL LIKELY CRANK UP TO SOME DEGREE OVERNIGHT. 850MB TEMPS
WILL DROP TO ROUGHLY -16C BEHIND A THIRD SHORTWAVE DIVING THROUGH
THE CENTRAL GREAT LAKES AROUND 06Z. NEARLY IDEAL 340 DEGREE FETCH
DEVELOPS BUT LAKE INDUCED CONVECTION WILL BE BATTLING INCREASING DRY
AIR ENTRAINMENT AND A STRENGTHENING SUBSIDENCE INVERSION. CONVECTIVE
DEPTHS ARE ONLY AROUND 5 KFT AND DROP EVEN LOWER BY FRIDAY MORNING.
ON THE OTHER HAND...MUCH OF THE LAKE EFFECT CLOUD LAYER WILL BE IN
THE PREFERRED -12 TO -18C DENDRITIC GROWTH ZONE (ESPECIALLY BY LATE
THURSDAY NIGHT) AND BOTH NAM AND GFS BUFR SOUNDINGS SHOW GOOD
SUPERSATURATION WITH RESPECT TO ICE IN THAT LAYER. NOT EXPECTING ANY
SIGNIFICANT ACCUMULATIONS BUT AN INCH OR TWO IS CERTAINLY POSSIBLE
IN BERRIEN COUNTY AND HAVE RAISED POPS ACCORDINGLY. OTHER COUNTIES
MAY ALSO SEE A LIGHT DUSTING WITH STRONG BOUNDARY LAYER WINDS LIKELY
PUSHING ORPHANED BANDS PRETTY FAR INLAND.

NOW ON TO THE ELEPHANT IN THE ROOM. 00Z DETERMINISTIC GUIDANCE
TRENDED MUCH SLOWER...DEEPER...AND FURTHER NORTHWEST WITH THE
MIDLATITUDE CYCLONE SLATED TO DEVELOP OVER THE EASTERN CONUS LATE
SUNDAY. 00Z GFS IN PARTICULAR PAINTS AN OMINOUS PICTURE. HOWEVER...A
PRUDENT AND JUDICIOUS APPROACH IS DEMANDED AT THESE TIME RANGES.
CIRCUMSTANCES THAT CONSPIRE TO PRODUCE STORM DEPICTED IN THE 00Z GFS
ARE COMPLICATED TO SAY THE LEAST...INVOLVING THE INTERACTION OF
SOUTHWEST CONUS CUTOFF LOW AND TWO DISTINCT NORTHERN STREAM
SHORTWAVES THAT ARE SHOWN TO PHASE AND PRODUCE A STRONG/NEGATIVELY
TILTED TROUGH OVER THE OHIO VALLEY. SHORTWAVES IN QUESTION HAVE NOT
EVEN DEVELOPED YET MUCH LESS BEEN SAMPLED. FURTHERMORE...ENSEMBLE
MEMBERS STILL SHOW A HIGH DEGREE OF SPREAD AND ECMWF DEPICTS A LESS
ROBUST CYCLONE. RUN TO RUN VARIABILITY HAS ALSO BEEN VERY HIGH FOR
THIS TIME RANGE. ALL OF THIS IS TO SAY THAT FORECAST CONFIDENCE IS
VERY LOW AT THIS POINT...MUCH LOWER THAN EVEN A TYPICAL DAY5
FORECAST. CERTAINLY THE CHANCES FOR PRECIP ON SUNDAY ARE INCREASING
AND THE NEW FORECAST REFLECTS THAT BUT DETAILS REGARDING AMOUNTS AND
TYPES ARE VERY MUCH IN FLUX. STAY TUNED TO THE LATEST FORECASTS OVER
THE COMING DAYS AS DETAILS ARE ALMOST CERTAIN TO CHANGE.

STILL EXPECTING A BLAST OF MUCH COLDER AIR BEHIND THIS SYSTEM EARLY
NEXT WEEK. HIGHS WILL LIKELY REMAIN IN THE TEENS WITH OVERNIGHT LOWS
POTENTIALLY IN THE NEGATIVE SINGLE DIGITS. A BRIEF SHOT OF LAKE
EFFECT SNOW IS ALSO POSSIBLE IN THE COLD WAKE OF EXITING CYCLONE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1251 AM EST WED JAN 28 2015

LOW LEVEL ANTICYCLONE WILL BRING CONTINUED LIGHT AND VARIABLE
WINDS THROUGH EARLY THIS MORNING. SOUTHEAST WINDS WILL DEVELOP AS
THIS HIGH PRESSURE DEPARTS TO THE EAST TODAY...WITH STRONGEST LATE
AFTERNOON GRADIENT SETTING UP ACROSS NORTHWEST INDIANA WHERE SOME
LATE AFTERNOON SOUTHEAST GUSTS INTO THE 15 TO 18 KNOT RANGE ARE
POSSIBLE. A SOUTHWESTERLY LOW LEVEL JET IN ADVANCE OF NEXT SYSTEM
LATE TONIGHT INTO EARLY THURSDAY WILL ALLOW FOR SOUTHEAST WINDS IN
THE 15G20-25 KNOT RANGE FOR TONIGHT WITH SOME INDICATIONS THAT
LLWS MAY BECOME A CONCERN MAINLY OUTSIDE OF THIS FORECAST PERIOD
IN THE 06Z-12Z TIMEFRAME EARLY THURSDAY MORNING. MID AND HIGH
LEVEL CLOUDINESS TO INCREASE TODAY...WITH DETERIORATING CIGS NOT
ANTICIPATED UNTIL AFTER THIS FORECAST VALID PERIOD. SOME LIGHT
SNOW/RAIN/FREEZING RAIN CONCERNS SHOULD ALSO HOLD OFF UNTIL MAINLY
AFTER THIS FORECAST VALID PERIOD AS NEXT SYSTEM APPROACHES...WHICH
WILL NEED TO BE ADDRESSED IN GREATER DEPTH FOR THE 12Z TAFS.

&&

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

$$

SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...AGD
AVIATION...MARSILI


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 280906
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
406 AM EST WED JAN 28 2015

.SYNOPSIS...
ISSUED AT 401 AM EST WED JAN 28 2015

CLOUDS WILL INCREASE TODAY AS A RIDGE OF HIGH PRESSURE SHIFTS OFF TO
THE EAST. AN UPPER LEVEL DISTURBANCE ACROSS THE ROCKIES WILL TRACK
INTO THE GREAT LAKES AND OHIO VALLEY REGIONS TONIGHT BRINGING A
WINTRY MIX LATE TONIGHT INTO THURSDAY. SOME MINOR ICE AND SNOW
ACCUMULATIONS ARE POSSIBLE...PARTICULARLY ACROSS FAR NORTHERN
INDIANA...MUCH OF LOWER MICHIGAN...AND NORTHWEST OHIO. HIGH
TEMPERATURES TODAY WILL RANGE FROM THE UPPER 30S ACROSS NORTHEAST
ILLINOIS TO THE UPPER 20S ACROSS NORTHWEST OHIO AND SOUTHEAST LOWER
MICHIGAN. STEADY OR SLOWLY RISING TEMPERATURES ARE EXPECTED THROUGH
MUCH OF TONIGHT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM EST WED JAN 28 2015

AFTER CONTINUED QUIET WEATHER CONDITIONS TODAY...ATTENTION FOR
TONIGHT WILL TURN TO NEXT SYSTEM THAT COULD BRING A WINTRY MIX TO
THE AREA INTO THURSDAY.

LARGE SCALE SUBSIDENCE CONTINUES EARLY THIS MORNING AS UPSTREAM
UPPER LEVEL RIDGE AXIS BEGINS TO SHIFT EASTWARD ACROSS THE SOUTHERN
GREAT LAKES TODAY. SOUTHERLY FLOW WILL INCREASE TOADY AS LOW LEVEL
ANTICYCLONE SHIFTS EASTWARD...WITH MAINLY JUST AN INCREASE IN MID
AND HIGH LEVEL CLOUDINESS THROUGH THE DAY AS MID LEVEL WAA
STRENGTHENS MORE SUBSTANTIALLY LATE THIS AFTERNOON. DESPITE
STRENGTHENING LOW LEVEL WAA LATER...A VERY STRONG LOW LEVEL
INVERSION WILL LIMIT AFTERNOON TEMPS...ESPECIALLY CONSIDERING
THICKENING MID LEVEL CLOUDS LATER THIS AFTERNOON. PREVIOUS
FORECASTED MAX TEMPS FROM LOWER TO MID 30S WEST...TO UPPER 20S
EAST...STILL APPEAR REASONABLE.

A FAIRLY ROBUST UPPER LEVEL PV ANOMALY APPROACHING THE ROCKIES
THIS MORNING WILL REACH THE SOUTHERN GREAT LAKES/OHIO VALLEY BY
EARLY THURSDAY MORNING. AN AXIS OF 40-50 KNOT SOUTHWESTERLY LOW
LEVEL FLOW PRECEDING THIS UPPER PV ANOMALY WILL ALLOW FOR ZONE OF
STRONG ISENTROPIC LIFT AND AN AXIS OF LOW/MID LEVEL MOISTURE
CONVERGENCE WORKING FROM WEST TO EAST ACROSS THE AREA THIS EVENING
INTO THE EARLY PORTIONS OF THE OVERNIGHT. DIFFERENTIAL WARM
ADVECTION WILL ALSO ALLOW PLUME OF FAIRLY STEEP MID LEVEL LAPSE
RATES TO OVERSPREAD THE AREA DURING THE EVENING HOURS. WHILE UPPER
FORCING WILL STILL LAG TO THE WEST FOR MUCH OF THE NIGHT...NAM/GFS
DO DEPICT STRENGTHENING 850-700 HPA QVEC CONVG SIGNAL OVERSPREADING
AREA THIS EVENING...WHICH WILL BE FOLLOWED BY PERIOD OF MORE
PRONOUNCED UPPER FORCING LATE TONIGHT INTO EARLY THURSDAY.

PTYPE QUESTIONS STILL ARE THE MAIN CONCERN WITH THIS SYSTEM AS
SUBSTANTIAL LOW LEVEL WARM LAYER ADVECTING INTO THE AREA AND AN
INITIALLY DRY LOW/MID LEVEL AIR MASS (EVAPORATIVE COOLING EFFECTS)
WILL MAKE FOR CHALLENGING FORECAST. DID MAINTAIN SOME LOW TO MID
RANGE CHANCE POPS LATE EVENING INTO THE EARLY PORTION OF OVERNIGHT
GIVEN AXIS OF STRONG LOW/MID LEVEL THETAE ADVECTION AND STEEPENING
MID LEVEL LAPSE RATES...WITH SOME LIGHT FREEZING RAIN POSSIBLE
ESPECIALLY AT PRECIP ONSET. IT DOES APPEAR AS THOUGH PRECIP ACROSS
THE WEST SHOULD TRANSITION TO LIQUID AS PRIMARY LOW LEVEL MOISTURE
AXIS SHIFTS INTO THE AREA ALONG WITH NON-DIURNAL TEMP CURVE AND
TEMPS RISING INTO THE MID 30S. ACROSS THE FAR NORTH AND
PARTICULARLY THE NORTHEAST PORTIONS OF THE CWA WHERE A WEAKER WARM
LAYER IS EXPECTED...MIXED PRECIP IN THE FORM OF LIGHT FREEZING
RAIN/SLEET/SNOW MAY BE MORE OF AN ISSUE THROUGH EARLY THURSDAY
MORNING. SOME LIGHT ICE ACCUMULATION IS POSSIBLE MAINLY NORTH OF
ROUTE 30...WITH PERHAPS BEST CHANCE OF MEASURABLE ICE ACCUMULATION
ACROSS EXTREME NORTHEAST INDIANA INTO PORTIONS OF SOUTH CENTRAL
LOWER MICHIGAN AND NORTHWEST OHIO. CONFIDENCE IN MIXED PRECIP
DURATION/LOCATION A BIT TOO LOW FOR ANY HEADLINES AT THIS TIME BUT
WILL NEED TO MONITOR THIS CLOSELY DUE TO TIMING WITH THURSDAY
MORNING COMMUTE. THE POSSIBILITY DOES EXIST THAT AN ADVISORY WILL
BE NEEDED FOR THIS PERIOD FOR PORTIONS OF THE AREA.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 401 AM EST WED JAN 28 2015

ACTIVE LONG TERM PERIOD WITH NUMEROUS ISSUES TO DISCUSS. THURSDAY`S
WINTRY MIX AND POTENTIAL SUNDAY STORM ARE THE PRIMARY ITEMS OF NOTE
BUT THERE WILL BE INTERMEDIATE PERIODS OF LAKE EFFECT SNOW AS WELL
AND AT LEAST A BRIEF RETURN TO MUCH COLDER TEMPS EARLY NEXT WEEK.

PRECIP TYPES FOR THURSDAY STILL APPEAR VERY MESSY. CONTINUED WARM
AND MOIST AIR ADVECTION WITH STRONG SOUTHERLY WINDS AT THE SURFACE
WILL PUSH WET BULB TEMPS ABOVE FREEZING BY THURSDAY MORNING.
FREEZING RAIN SHOULD TRANSITION TO JUST RAIN BY 12Z THURSDAY IN ALL
BUT OUR FAR NORTHEAST COUNTIES WHERE IT MAY PERSIST FOR AN HOUR OR
TWO LONGER. HOWEVER...ARRIVAL OF SECONDARY NORTHERN STREAM VORT MAX
WILL DO TWO THINGS. ONE...INCREASE COVERAGE OF MEASURABLE PRECIP IN
OUR CWA FOR THE MIDDAY PERIOD WITH AN ADDED BUMP OF CVA-FORCED
ASCENT IN A VERY MOIST ENVIRONMENT. AND TWO...ALLOW COLDER AIR TO
FILTER BACK INTO THE AREA BEHIND SURFACE LOW TRACKING EASTWARD. THIS
WILL FORCE A CHANGEOVER TO SNOW FROM NORTH TO SOUTH DURING THE
AFTERNOON WITH A PERIOD OF SLEET ALSO POSSIBLE DURING THE
TRANSITION. EXPECTING LITTLE IF ANY ACCUMULATION THOUGH. TROWAL AXIS
AND BEST MIDLEVEL CVA BYPASS US TO THE NORTH AND WARM/WET GROUND
WILL PREVENT MOST OF WHAT DOES FALL FROM ACCUMULATING. THINK A FEW
TENTHS AT BEST FOR MOST AREAS WITH UP TO AN INCH POSSIBLE IN OUR FAR
NORTHEAST COUNTIES.

SYNOPTICALLY DRIVEN SNOW WILL EXIT BY THURSDAY EVENING BUT LAKE
EFFECT WILL LIKELY CRANK UP TO SOME DEGREE OVERNIGHT. 850MB TEMPS
WILL DROP TO ROUGHLY -16C BEHIND A THIRD SHORTWAVE DIVING THROUGH
THE CENTRAL GREAT LAKES AROUND 06Z. NEARLY IDEAL 340 DEGREE FETCH
DEVELOPS BUT LAKE INDUCED CONVECTION WILL BE BATTLING INCREASING DRY
AIR ENTRAINMENT AND A STRENGTHENING SUBSIDENCE INVERSION. CONVECTIVE
DEPTHS ARE ONLY AROUND 5 KFT AND DROP EVEN LOWER BY FRIDAY MORNING.
ON THE OTHER HAND...MUCH OF THE LAKE EFFECT CLOUD LAYER WILL BE IN
THE PREFERRED -12 TO -18C DENDRITIC GROWTH ZONE (ESPECIALLY BY LATE
THURSDAY NIGHT) AND BOTH NAM AND GFS BUFR SOUNDINGS SHOW GOOD
SUPERSATURATION WITH RESPECT TO ICE IN THAT LAYER. NOT EXPECTING ANY
SIGNIFICANT ACCUMULATIONS BUT AN INCH OR TWO IS CERTAINLY POSSIBLE
IN BERRIEN COUNTY AND HAVE RAISED POPS ACCORDINGLY. OTHER COUNTIES
MAY ALSO SEE A LIGHT DUSTING WITH STRONG BOUNDARY LAYER WINDS LIKELY
PUSHING ORPHANED BANDS PRETTY FAR INLAND.

NOW ON TO THE ELEPHANT IN THE ROOM. 00Z DETERMINISTIC GUIDANCE
TRENDED MUCH SLOWER...DEEPER...AND FURTHER NORTHWEST WITH THE
MIDLATITUDE CYCLONE SLATED TO DEVELOP OVER THE EASTERN CONUS LATE
SUNDAY. 00Z GFS IN PARTICULAR PAINTS AN OMINOUS PICTURE. HOWEVER...A
PRUDENT AND JUDICIOUS APPROACH IS DEMANDED AT THESE TIME RANGES.
CIRCUMSTANCES THAT CONSPIRE TO PRODUCE STORM DEPICTED IN THE 00Z GFS
ARE COMPLICATED TO SAY THE LEAST...INVOLVING THE INTERACTION OF
SOUTHWEST CONUS CUTOFF LOW AND TWO DISTINCT NORTHERN STREAM
SHORTWAVES THAT ARE SHOWN TO PHASE AND PRODUCE A STRONG/NEGATIVELY
TILTED TROUGH OVER THE OHIO VALLEY. SHORTWAVES IN QUESTION HAVE NOT
EVEN DEVELOPED YET MUCH LESS BEEN SAMPLED. FURTHERMORE...ENSEMBLE
MEMBERS STILL SHOW A HIGH DEGREE OF SPREAD AND ECMWF DEPICTS A LESS
ROBUST CYCLONE. RUN TO RUN VARIABILITY HAS ALSO BEEN VERY HIGH FOR
THIS TIME RANGE. ALL OF THIS IS TO SAY THAT FORECAST CONFIDENCE IS
VERY LOW AT THIS POINT...MUCH LOWER THAN EVEN A TYPICAL DAY5
FORECAST. CERTAINLY THE CHANCES FOR PRECIP ON SUNDAY ARE INCREASING
AND THE NEW FORECAST REFLECTS THAT BUT DETAILS REGARDING AMOUNTS AND
TYPES ARE VERY MUCH IN FLUX. STAY TUNED TO THE LATEST FORECASTS OVER
THE COMING DAYS AS DETAILS ARE ALMOST CERTAIN TO CHANGE.

STILL EXPECTING A BLAST OF MUCH COLDER AIR BEHIND THIS SYSTEM EARLY
NEXT WEEK. HIGHS WILL LIKELY REMAIN IN THE TEENS WITH OVERNIGHT LOWS
POTENTIALLY IN THE NEGATIVE SINGLE DIGITS. A BRIEF SHOT OF LAKE
EFFECT SNOW IS ALSO POSSIBLE IN THE COLD WAKE OF EXITING CYCLONE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1251 AM EST WED JAN 28 2015

LOW LEVEL ANTICYCLONE WILL BRING CONTINUED LIGHT AND VARIABLE
WINDS THROUGH EARLY THIS MORNING. SOUTHEAST WINDS WILL DEVELOP AS
THIS HIGH PRESSURE DEPARTS TO THE EAST TODAY...WITH STRONGEST LATE
AFTERNOON GRADIENT SETTING UP ACROSS NORTHWEST INDIANA WHERE SOME
LATE AFTERNOON SOUTHEAST GUSTS INTO THE 15 TO 18 KNOT RANGE ARE
POSSIBLE. A SOUTHWESTERLY LOW LEVEL JET IN ADVANCE OF NEXT SYSTEM
LATE TONIGHT INTO EARLY THURSDAY WILL ALLOW FOR SOUTHEAST WINDS IN
THE 15G20-25 KNOT RANGE FOR TONIGHT WITH SOME INDICATIONS THAT
LLWS MAY BECOME A CONCERN MAINLY OUTSIDE OF THIS FORECAST PERIOD
IN THE 06Z-12Z TIMEFRAME EARLY THURSDAY MORNING. MID AND HIGH
LEVEL CLOUDINESS TO INCREASE TODAY...WITH DETERIORATING CIGS NOT
ANTICIPATED UNTIL AFTER THIS FORECAST VALID PERIOD. SOME LIGHT
SNOW/RAIN/FREEZING RAIN CONCERNS SHOULD ALSO HOLD OFF UNTIL MAINLY
AFTER THIS FORECAST VALID PERIOD AS NEXT SYSTEM APPROACHES...WHICH
WILL NEED TO BE ADDRESSED IN GREATER DEPTH FOR THE 12Z TAFS.

&&

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

$$

SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...AGD
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 280559
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1259 AM EST WED JAN 28 2015

.SYNOPSIS...
ISSUED AT 754 PM EST TUE JAN 27 2015

MOSTLY CLEAR SKIES WILL BRING TEMPERATURES DOWN INTO THE SINGLE
DIGITS AND LOW TEENS. CLOUD COVER WILL INCREASE THROUGHOUT THE DAY
ON WEDNESDAY AS THE NEXT LOW PRESSURE SYSTEM APPROACHES THE AREA.
HIGHS WILL BE IN THE UPPER 20S AND LOW TO MID 30S. EXPECT A WINTRY
MIX OF PRECIPITATION WEDNESDAY NIGHT INTO THURSDAY...WITH MINOR
ICE AND SNOW ACCUMULATIONS POSSIBLE.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 326 PM EST TUE JAN 27 2015

DEEP LAYERED QG SUBSIDENCE IN WAKE OF AN EXITING EAST COAST TROUGH
WILL CONTINUE TO PROMOTE QUIET/MAINLY CLEAR CONDITIONS INTO
TONIGHT/TOMORROW. ASSOCIATED SFC HIGH SETTLING SOUTH OVER THE AREA
IN TANDEM WITH MAINLY CLEAR SKIES/LIGHT WINDS WILL PRODUCE OPTIMAL
RADIATIONAL COOLING TONIGHT. AS A RESULT CONTINUED TO FAVOR COOLER
GUIDANCE FOR OVERNIGHT LOWS. RETURN SOUTHWEST FLOW BY WEDNESDAY
AFTERNOON AND JUST A GRADUAL INCREASE IN MID-HIGH CLOUDS SHOULD
ALLOW WEDNESDAY HIGHS TO RUN A FEW DEGREES WARMER THAN TODAY.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 326 PM EST TUE JAN 27 2015

INITIAL FOCUS WILL BE ON 2 WAVES THAT WILL ATTEMPT TO PHASE SOMEWHAT
ACROSS THE GREAT LAKES INTO THURSDAY. FIRST WAVE WILL BE SCOOTING
OUT OF THE PLAINS AT THE ONSET WITH WEAK CLIPPER MOVING RAPIDLY SE
OUT OF CANADA. PLAINS SYSTEM WILL HAVE A LARGE WARM TONGUE THAT WILL
ACCOMPANY IT AND MOVE INTO THE AREA WEDNESDAY NIGHT. MSTR WILL
INITIALLY BE LIMITED BUT RAPID SATURATION THROUGH 800 MB WILL TAKE
PLACE TOWARDS THURSDAY MORNING. WEDGE OF WARM AIR WILL MOVE IN
BETWEEN 800 AND 900 MB AND COMPLICATE PRECIP TYPE. WARMEST AIR WILL
BE IN PLACE AT THE ONSET WITH COOLING EFFECTS OF SATURATION AS WELL
AS APPROACH OF CANADIAN WAVE ALL LEADING TOWARDS AN EVENTUAL
TRANSITION TO COLDER PROFILES AND CHANGE OVER TO MORE SLEET/SNOW.
NOW WITH ALL THAT BEING SAID...THE BEST LIFT AND DYNAMICS WILL PASS
ACROSS THE FAR NORTHERN PARTS OF THE AREA WITH MAIN IMPACTS ACROSS
LWR MI WHERE PEAK ISENTROPIC LIFT AND FAVORABLE LOW/MID LEVEL LOW
TRACK OCCURS. GRIDS REFLECT A RATHER MESSY SETUP WITH THERMAL
PROFILES STILL HIGHLY SUSPECT CAUSING A LOW CONFIDENCE FORECAST IN
TERMS OF IMPACTS AND DURATION. SFC TEMPS WILL HOVER NEAR OR JUST
BELOW FREEZING MOST OF THE NIGHT BEFORE BEGINNING TO FALL OFF DURING
THE AFTERNOON HOURS OF THURSDAY. ANY PRECIP BY THIS TIME SHOULD
TRANSITION TO ALL SNOW WITH MAYBE A DUSTING IN SOME SPOTS.

TOUCH OF LAKE EFFECT SNOW SHOWERS WILL OCCUR THURSDAY NIGHT AS
STRONG NW FLOW SETS UP. HOWEVER...DESPITE INCREASING DELTA T`S MSTR
WILL BE ON THE DECREASE WHICH SHOULD LIMIT ANY IMPACTS AND KEEP
ACCUMULATIONS ON THE VERY LGT SIDE.

FOCUS SHIFTS TO NORTHERN AND SOUTHERN STREAM SYSTEM AND IMPACTS OVER
THE WEEKEND WITH MODELS STILL HAVING NO CLUE AS TO WHAT MAY EVOLVE.
GFS/ECMWF STILL SUGGEST DECENT CYCLOGENESIS TAKING PLACE MORE EAST
OF THE FORECAST AREA AS TROUGH TAKES ON A NEGATIVE TILT. CHANCES FOR
SOME SNOWFALL LOOK TO BE INCREASING ESPECIALLY INTO PORTIONS OF OHIO
CLOSER TO THE SUGGESTED TRACK. GIVEN TRACK RECORD OF EXTENDED MODELS
THUS FAR THIS MANY DAYS OUT...LOW CONFIDENCE ON WHAT WILL
UNFOLD...RESULTING IN A LOWERING OF BLEND OF MODEL GUIDANCE TO MID
TO HIGH CHANCE POPS FOR NOW. SYSTEM DOES HAVE THE POTENTIAL TO BRING
SEVERAL INCHES OF SNOW TO PARTS OF THE REGION SUNDAY INTO MONDAY SO
WILL NEED TO MONITOR TRENDS AND HOPE MODELS CAN COME TO SOME
AGREEMENT WITH TIME. MUCH COLDER AIR WILL FILTER IN BEHIND THE
SYSTEM WITH HIGHS IN THE SINGLE DIGITS AND TEENS ABOVE AND LOWS AT
OR BELOW ZERO.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1251 AM EST WED JAN 28 2015

LOW LEVEL ANTICYCLONE WILL BRING CONTINUED LIGHT AND VARIABLE
WINDS THROUGH EARLY THIS MORNING. SOUTHEAST WINDS WILL DEVELOP AS
THIS HIGH PRESSURE DEPARTS TO THE EAST TODAY...WITH STRONGEST LATE
AFTERNOON GRADIENT SETTING UP ACROSS NORTHWEST INDIANA WHERE SOME
LATE AFTERNOON SOUTHEAST GUSTS INTO THE 15 TO 18 KNOT RANGE ARE
POSSIBLE. A SOUTHWESTERLY LOW LEVEL JET IN ADVANCE OF NEXT SYSTEM
LATE TONIGHT INTO EARLY THURSDAY WILL ALLOW FOR SOUTHEAST WINDS IN
THE 15G20-25 KNOT RANGE FOR TONIGHT WITH SOME INDICATIONS THAT
LLWS MAY BECOME A CONCERN MAINLY OUTSIDE OF THIS FORECAST PERIOD
IN THE 06Z-12Z TIMEFRAME EARLY THURSDAY MORNING. MID AND HIGH
LEVEL CLOUDINESS TO INCREASE TODAY...WITH DETERIORATING CIGS NOT
ANTICIPATED UNTIL AFTER THIS FORECAST VALID PERIOD. SOME LIGHT
SNOW/RAIN/FREEZING RAIN CONCERNS SHOULD ALSO HOLD OFF UNTIL MAINLY
AFTER THIS FORECAST VALID PERIOD AS NEXT SYSTEM APPROACHES...WHICH
WILL NEED TO BE ADDRESSED IN GREATER DEPTH FOR THE 12Z TAFS.

&&

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

$$

SYNOPSIS...MCD
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:
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000
FXUS63 KIWX 280559
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1259 AM EST WED JAN 28 2015

.SYNOPSIS...
ISSUED AT 754 PM EST TUE JAN 27 2015

MOSTLY CLEAR SKIES WILL BRING TEMPERATURES DOWN INTO THE SINGLE
DIGITS AND LOW TEENS. CLOUD COVER WILL INCREASE THROUGHOUT THE DAY
ON WEDNESDAY AS THE NEXT LOW PRESSURE SYSTEM APPROACHES THE AREA.
HIGHS WILL BE IN THE UPPER 20S AND LOW TO MID 30S. EXPECT A WINTRY
MIX OF PRECIPITATION WEDNESDAY NIGHT INTO THURSDAY...WITH MINOR
ICE AND SNOW ACCUMULATIONS POSSIBLE.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 326 PM EST TUE JAN 27 2015

DEEP LAYERED QG SUBSIDENCE IN WAKE OF AN EXITING EAST COAST TROUGH
WILL CONTINUE TO PROMOTE QUIET/MAINLY CLEAR CONDITIONS INTO
TONIGHT/TOMORROW. ASSOCIATED SFC HIGH SETTLING SOUTH OVER THE AREA
IN TANDEM WITH MAINLY CLEAR SKIES/LIGHT WINDS WILL PRODUCE OPTIMAL
RADIATIONAL COOLING TONIGHT. AS A RESULT CONTINUED TO FAVOR COOLER
GUIDANCE FOR OVERNIGHT LOWS. RETURN SOUTHWEST FLOW BY WEDNESDAY
AFTERNOON AND JUST A GRADUAL INCREASE IN MID-HIGH CLOUDS SHOULD
ALLOW WEDNESDAY HIGHS TO RUN A FEW DEGREES WARMER THAN TODAY.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 326 PM EST TUE JAN 27 2015

INITIAL FOCUS WILL BE ON 2 WAVES THAT WILL ATTEMPT TO PHASE SOMEWHAT
ACROSS THE GREAT LAKES INTO THURSDAY. FIRST WAVE WILL BE SCOOTING
OUT OF THE PLAINS AT THE ONSET WITH WEAK CLIPPER MOVING RAPIDLY SE
OUT OF CANADA. PLAINS SYSTEM WILL HAVE A LARGE WARM TONGUE THAT WILL
ACCOMPANY IT AND MOVE INTO THE AREA WEDNESDAY NIGHT. MSTR WILL
INITIALLY BE LIMITED BUT RAPID SATURATION THROUGH 800 MB WILL TAKE
PLACE TOWARDS THURSDAY MORNING. WEDGE OF WARM AIR WILL MOVE IN
BETWEEN 800 AND 900 MB AND COMPLICATE PRECIP TYPE. WARMEST AIR WILL
BE IN PLACE AT THE ONSET WITH COOLING EFFECTS OF SATURATION AS WELL
AS APPROACH OF CANADIAN WAVE ALL LEADING TOWARDS AN EVENTUAL
TRANSITION TO COLDER PROFILES AND CHANGE OVER TO MORE SLEET/SNOW.
NOW WITH ALL THAT BEING SAID...THE BEST LIFT AND DYNAMICS WILL PASS
ACROSS THE FAR NORTHERN PARTS OF THE AREA WITH MAIN IMPACTS ACROSS
LWR MI WHERE PEAK ISENTROPIC LIFT AND FAVORABLE LOW/MID LEVEL LOW
TRACK OCCURS. GRIDS REFLECT A RATHER MESSY SETUP WITH THERMAL
PROFILES STILL HIGHLY SUSPECT CAUSING A LOW CONFIDENCE FORECAST IN
TERMS OF IMPACTS AND DURATION. SFC TEMPS WILL HOVER NEAR OR JUST
BELOW FREEZING MOST OF THE NIGHT BEFORE BEGINNING TO FALL OFF DURING
THE AFTERNOON HOURS OF THURSDAY. ANY PRECIP BY THIS TIME SHOULD
TRANSITION TO ALL SNOW WITH MAYBE A DUSTING IN SOME SPOTS.

TOUCH OF LAKE EFFECT SNOW SHOWERS WILL OCCUR THURSDAY NIGHT AS
STRONG NW FLOW SETS UP. HOWEVER...DESPITE INCREASING DELTA T`S MSTR
WILL BE ON THE DECREASE WHICH SHOULD LIMIT ANY IMPACTS AND KEEP
ACCUMULATIONS ON THE VERY LGT SIDE.

FOCUS SHIFTS TO NORTHERN AND SOUTHERN STREAM SYSTEM AND IMPACTS OVER
THE WEEKEND WITH MODELS STILL HAVING NO CLUE AS TO WHAT MAY EVOLVE.
GFS/ECMWF STILL SUGGEST DECENT CYCLOGENESIS TAKING PLACE MORE EAST
OF THE FORECAST AREA AS TROUGH TAKES ON A NEGATIVE TILT. CHANCES FOR
SOME SNOWFALL LOOK TO BE INCREASING ESPECIALLY INTO PORTIONS OF OHIO
CLOSER TO THE SUGGESTED TRACK. GIVEN TRACK RECORD OF EXTENDED MODELS
THUS FAR THIS MANY DAYS OUT...LOW CONFIDENCE ON WHAT WILL
UNFOLD...RESULTING IN A LOWERING OF BLEND OF MODEL GUIDANCE TO MID
TO HIGH CHANCE POPS FOR NOW. SYSTEM DOES HAVE THE POTENTIAL TO BRING
SEVERAL INCHES OF SNOW TO PARTS OF THE REGION SUNDAY INTO MONDAY SO
WILL NEED TO MONITOR TRENDS AND HOPE MODELS CAN COME TO SOME
AGREEMENT WITH TIME. MUCH COLDER AIR WILL FILTER IN BEHIND THE
SYSTEM WITH HIGHS IN THE SINGLE DIGITS AND TEENS ABOVE AND LOWS AT
OR BELOW ZERO.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1251 AM EST WED JAN 28 2015

LOW LEVEL ANTICYCLONE WILL BRING CONTINUED LIGHT AND VARIABLE
WINDS THROUGH EARLY THIS MORNING. SOUTHEAST WINDS WILL DEVELOP AS
THIS HIGH PRESSURE DEPARTS TO THE EAST TODAY...WITH STRONGEST LATE
AFTERNOON GRADIENT SETTING UP ACROSS NORTHWEST INDIANA WHERE SOME
LATE AFTERNOON SOUTHEAST GUSTS INTO THE 15 TO 18 KNOT RANGE ARE
POSSIBLE. A SOUTHWESTERLY LOW LEVEL JET IN ADVANCE OF NEXT SYSTEM
LATE TONIGHT INTO EARLY THURSDAY WILL ALLOW FOR SOUTHEAST WINDS IN
THE 15G20-25 KNOT RANGE FOR TONIGHT WITH SOME INDICATIONS THAT
LLWS MAY BECOME A CONCERN MAINLY OUTSIDE OF THIS FORECAST PERIOD
IN THE 06Z-12Z TIMEFRAME EARLY THURSDAY MORNING. MID AND HIGH
LEVEL CLOUDINESS TO INCREASE TODAY...WITH DETERIORATING CIGS NOT
ANTICIPATED UNTIL AFTER THIS FORECAST VALID PERIOD. SOME LIGHT
SNOW/RAIN/FREEZING RAIN CONCERNS SHOULD ALSO HOLD OFF UNTIL MAINLY
AFTER THIS FORECAST VALID PERIOD AS NEXT SYSTEM APPROACHES...WHICH
WILL NEED TO BE ADDRESSED IN GREATER DEPTH FOR THE 12Z TAFS.

&&

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

$$

SYNOPSIS...MCD
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 280559
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1259 AM EST WED JAN 28 2015

.SYNOPSIS...
ISSUED AT 754 PM EST TUE JAN 27 2015

MOSTLY CLEAR SKIES WILL BRING TEMPERATURES DOWN INTO THE SINGLE
DIGITS AND LOW TEENS. CLOUD COVER WILL INCREASE THROUGHOUT THE DAY
ON WEDNESDAY AS THE NEXT LOW PRESSURE SYSTEM APPROACHES THE AREA.
HIGHS WILL BE IN THE UPPER 20S AND LOW TO MID 30S. EXPECT A WINTRY
MIX OF PRECIPITATION WEDNESDAY NIGHT INTO THURSDAY...WITH MINOR
ICE AND SNOW ACCUMULATIONS POSSIBLE.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 326 PM EST TUE JAN 27 2015

DEEP LAYERED QG SUBSIDENCE IN WAKE OF AN EXITING EAST COAST TROUGH
WILL CONTINUE TO PROMOTE QUIET/MAINLY CLEAR CONDITIONS INTO
TONIGHT/TOMORROW. ASSOCIATED SFC HIGH SETTLING SOUTH OVER THE AREA
IN TANDEM WITH MAINLY CLEAR SKIES/LIGHT WINDS WILL PRODUCE OPTIMAL
RADIATIONAL COOLING TONIGHT. AS A RESULT CONTINUED TO FAVOR COOLER
GUIDANCE FOR OVERNIGHT LOWS. RETURN SOUTHWEST FLOW BY WEDNESDAY
AFTERNOON AND JUST A GRADUAL INCREASE IN MID-HIGH CLOUDS SHOULD
ALLOW WEDNESDAY HIGHS TO RUN A FEW DEGREES WARMER THAN TODAY.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 326 PM EST TUE JAN 27 2015

INITIAL FOCUS WILL BE ON 2 WAVES THAT WILL ATTEMPT TO PHASE SOMEWHAT
ACROSS THE GREAT LAKES INTO THURSDAY. FIRST WAVE WILL BE SCOOTING
OUT OF THE PLAINS AT THE ONSET WITH WEAK CLIPPER MOVING RAPIDLY SE
OUT OF CANADA. PLAINS SYSTEM WILL HAVE A LARGE WARM TONGUE THAT WILL
ACCOMPANY IT AND MOVE INTO THE AREA WEDNESDAY NIGHT. MSTR WILL
INITIALLY BE LIMITED BUT RAPID SATURATION THROUGH 800 MB WILL TAKE
PLACE TOWARDS THURSDAY MORNING. WEDGE OF WARM AIR WILL MOVE IN
BETWEEN 800 AND 900 MB AND COMPLICATE PRECIP TYPE. WARMEST AIR WILL
BE IN PLACE AT THE ONSET WITH COOLING EFFECTS OF SATURATION AS WELL
AS APPROACH OF CANADIAN WAVE ALL LEADING TOWARDS AN EVENTUAL
TRANSITION TO COLDER PROFILES AND CHANGE OVER TO MORE SLEET/SNOW.
NOW WITH ALL THAT BEING SAID...THE BEST LIFT AND DYNAMICS WILL PASS
ACROSS THE FAR NORTHERN PARTS OF THE AREA WITH MAIN IMPACTS ACROSS
LWR MI WHERE PEAK ISENTROPIC LIFT AND FAVORABLE LOW/MID LEVEL LOW
TRACK OCCURS. GRIDS REFLECT A RATHER MESSY SETUP WITH THERMAL
PROFILES STILL HIGHLY SUSPECT CAUSING A LOW CONFIDENCE FORECAST IN
TERMS OF IMPACTS AND DURATION. SFC TEMPS WILL HOVER NEAR OR JUST
BELOW FREEZING MOST OF THE NIGHT BEFORE BEGINNING TO FALL OFF DURING
THE AFTERNOON HOURS OF THURSDAY. ANY PRECIP BY THIS TIME SHOULD
TRANSITION TO ALL SNOW WITH MAYBE A DUSTING IN SOME SPOTS.

TOUCH OF LAKE EFFECT SNOW SHOWERS WILL OCCUR THURSDAY NIGHT AS
STRONG NW FLOW SETS UP. HOWEVER...DESPITE INCREASING DELTA T`S MSTR
WILL BE ON THE DECREASE WHICH SHOULD LIMIT ANY IMPACTS AND KEEP
ACCUMULATIONS ON THE VERY LGT SIDE.

FOCUS SHIFTS TO NORTHERN AND SOUTHERN STREAM SYSTEM AND IMPACTS OVER
THE WEEKEND WITH MODELS STILL HAVING NO CLUE AS TO WHAT MAY EVOLVE.
GFS/ECMWF STILL SUGGEST DECENT CYCLOGENESIS TAKING PLACE MORE EAST
OF THE FORECAST AREA AS TROUGH TAKES ON A NEGATIVE TILT. CHANCES FOR
SOME SNOWFALL LOOK TO BE INCREASING ESPECIALLY INTO PORTIONS OF OHIO
CLOSER TO THE SUGGESTED TRACK. GIVEN TRACK RECORD OF EXTENDED MODELS
THUS FAR THIS MANY DAYS OUT...LOW CONFIDENCE ON WHAT WILL
UNFOLD...RESULTING IN A LOWERING OF BLEND OF MODEL GUIDANCE TO MID
TO HIGH CHANCE POPS FOR NOW. SYSTEM DOES HAVE THE POTENTIAL TO BRING
SEVERAL INCHES OF SNOW TO PARTS OF THE REGION SUNDAY INTO MONDAY SO
WILL NEED TO MONITOR TRENDS AND HOPE MODELS CAN COME TO SOME
AGREEMENT WITH TIME. MUCH COLDER AIR WILL FILTER IN BEHIND THE
SYSTEM WITH HIGHS IN THE SINGLE DIGITS AND TEENS ABOVE AND LOWS AT
OR BELOW ZERO.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1251 AM EST WED JAN 28 2015

LOW LEVEL ANTICYCLONE WILL BRING CONTINUED LIGHT AND VARIABLE
WINDS THROUGH EARLY THIS MORNING. SOUTHEAST WINDS WILL DEVELOP AS
THIS HIGH PRESSURE DEPARTS TO THE EAST TODAY...WITH STRONGEST LATE
AFTERNOON GRADIENT SETTING UP ACROSS NORTHWEST INDIANA WHERE SOME
LATE AFTERNOON SOUTHEAST GUSTS INTO THE 15 TO 18 KNOT RANGE ARE
POSSIBLE. A SOUTHWESTERLY LOW LEVEL JET IN ADVANCE OF NEXT SYSTEM
LATE TONIGHT INTO EARLY THURSDAY WILL ALLOW FOR SOUTHEAST WINDS IN
THE 15G20-25 KNOT RANGE FOR TONIGHT WITH SOME INDICATIONS THAT
LLWS MAY BECOME A CONCERN MAINLY OUTSIDE OF THIS FORECAST PERIOD
IN THE 06Z-12Z TIMEFRAME EARLY THURSDAY MORNING. MID AND HIGH
LEVEL CLOUDINESS TO INCREASE TODAY...WITH DETERIORATING CIGS NOT
ANTICIPATED UNTIL AFTER THIS FORECAST VALID PERIOD. SOME LIGHT
SNOW/RAIN/FREEZING RAIN CONCERNS SHOULD ALSO HOLD OFF UNTIL MAINLY
AFTER THIS FORECAST VALID PERIOD AS NEXT SYSTEM APPROACHES...WHICH
WILL NEED TO BE ADDRESSED IN GREATER DEPTH FOR THE 12Z TAFS.

&&

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

$$

SYNOPSIS...MCD
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 280559
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1259 AM EST WED JAN 28 2015

.SYNOPSIS...
ISSUED AT 754 PM EST TUE JAN 27 2015

MOSTLY CLEAR SKIES WILL BRING TEMPERATURES DOWN INTO THE SINGLE
DIGITS AND LOW TEENS. CLOUD COVER WILL INCREASE THROUGHOUT THE DAY
ON WEDNESDAY AS THE NEXT LOW PRESSURE SYSTEM APPROACHES THE AREA.
HIGHS WILL BE IN THE UPPER 20S AND LOW TO MID 30S. EXPECT A WINTRY
MIX OF PRECIPITATION WEDNESDAY NIGHT INTO THURSDAY...WITH MINOR
ICE AND SNOW ACCUMULATIONS POSSIBLE.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 326 PM EST TUE JAN 27 2015

DEEP LAYERED QG SUBSIDENCE IN WAKE OF AN EXITING EAST COAST TROUGH
WILL CONTINUE TO PROMOTE QUIET/MAINLY CLEAR CONDITIONS INTO
TONIGHT/TOMORROW. ASSOCIATED SFC HIGH SETTLING SOUTH OVER THE AREA
IN TANDEM WITH MAINLY CLEAR SKIES/LIGHT WINDS WILL PRODUCE OPTIMAL
RADIATIONAL COOLING TONIGHT. AS A RESULT CONTINUED TO FAVOR COOLER
GUIDANCE FOR OVERNIGHT LOWS. RETURN SOUTHWEST FLOW BY WEDNESDAY
AFTERNOON AND JUST A GRADUAL INCREASE IN MID-HIGH CLOUDS SHOULD
ALLOW WEDNESDAY HIGHS TO RUN A FEW DEGREES WARMER THAN TODAY.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 326 PM EST TUE JAN 27 2015

INITIAL FOCUS WILL BE ON 2 WAVES THAT WILL ATTEMPT TO PHASE SOMEWHAT
ACROSS THE GREAT LAKES INTO THURSDAY. FIRST WAVE WILL BE SCOOTING
OUT OF THE PLAINS AT THE ONSET WITH WEAK CLIPPER MOVING RAPIDLY SE
OUT OF CANADA. PLAINS SYSTEM WILL HAVE A LARGE WARM TONGUE THAT WILL
ACCOMPANY IT AND MOVE INTO THE AREA WEDNESDAY NIGHT. MSTR WILL
INITIALLY BE LIMITED BUT RAPID SATURATION THROUGH 800 MB WILL TAKE
PLACE TOWARDS THURSDAY MORNING. WEDGE OF WARM AIR WILL MOVE IN
BETWEEN 800 AND 900 MB AND COMPLICATE PRECIP TYPE. WARMEST AIR WILL
BE IN PLACE AT THE ONSET WITH COOLING EFFECTS OF SATURATION AS WELL
AS APPROACH OF CANADIAN WAVE ALL LEADING TOWARDS AN EVENTUAL
TRANSITION TO COLDER PROFILES AND CHANGE OVER TO MORE SLEET/SNOW.
NOW WITH ALL THAT BEING SAID...THE BEST LIFT AND DYNAMICS WILL PASS
ACROSS THE FAR NORTHERN PARTS OF THE AREA WITH MAIN IMPACTS ACROSS
LWR MI WHERE PEAK ISENTROPIC LIFT AND FAVORABLE LOW/MID LEVEL LOW
TRACK OCCURS. GRIDS REFLECT A RATHER MESSY SETUP WITH THERMAL
PROFILES STILL HIGHLY SUSPECT CAUSING A LOW CONFIDENCE FORECAST IN
TERMS OF IMPACTS AND DURATION. SFC TEMPS WILL HOVER NEAR OR JUST
BELOW FREEZING MOST OF THE NIGHT BEFORE BEGINNING TO FALL OFF DURING
THE AFTERNOON HOURS OF THURSDAY. ANY PRECIP BY THIS TIME SHOULD
TRANSITION TO ALL SNOW WITH MAYBE A DUSTING IN SOME SPOTS.

TOUCH OF LAKE EFFECT SNOW SHOWERS WILL OCCUR THURSDAY NIGHT AS
STRONG NW FLOW SETS UP. HOWEVER...DESPITE INCREASING DELTA T`S MSTR
WILL BE ON THE DECREASE WHICH SHOULD LIMIT ANY IMPACTS AND KEEP
ACCUMULATIONS ON THE VERY LGT SIDE.

FOCUS SHIFTS TO NORTHERN AND SOUTHERN STREAM SYSTEM AND IMPACTS OVER
THE WEEKEND WITH MODELS STILL HAVING NO CLUE AS TO WHAT MAY EVOLVE.
GFS/ECMWF STILL SUGGEST DECENT CYCLOGENESIS TAKING PLACE MORE EAST
OF THE FORECAST AREA AS TROUGH TAKES ON A NEGATIVE TILT. CHANCES FOR
SOME SNOWFALL LOOK TO BE INCREASING ESPECIALLY INTO PORTIONS OF OHIO
CLOSER TO THE SUGGESTED TRACK. GIVEN TRACK RECORD OF EXTENDED MODELS
THUS FAR THIS MANY DAYS OUT...LOW CONFIDENCE ON WHAT WILL
UNFOLD...RESULTING IN A LOWERING OF BLEND OF MODEL GUIDANCE TO MID
TO HIGH CHANCE POPS FOR NOW. SYSTEM DOES HAVE THE POTENTIAL TO BRING
SEVERAL INCHES OF SNOW TO PARTS OF THE REGION SUNDAY INTO MONDAY SO
WILL NEED TO MONITOR TRENDS AND HOPE MODELS CAN COME TO SOME
AGREEMENT WITH TIME. MUCH COLDER AIR WILL FILTER IN BEHIND THE
SYSTEM WITH HIGHS IN THE SINGLE DIGITS AND TEENS ABOVE AND LOWS AT
OR BELOW ZERO.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1251 AM EST WED JAN 28 2015

LOW LEVEL ANTICYCLONE WILL BRING CONTINUED LIGHT AND VARIABLE
WINDS THROUGH EARLY THIS MORNING. SOUTHEAST WINDS WILL DEVELOP AS
THIS HIGH PRESSURE DEPARTS TO THE EAST TODAY...WITH STRONGEST LATE
AFTERNOON GRADIENT SETTING UP ACROSS NORTHWEST INDIANA WHERE SOME
LATE AFTERNOON SOUTHEAST GUSTS INTO THE 15 TO 18 KNOT RANGE ARE
POSSIBLE. A SOUTHWESTERLY LOW LEVEL JET IN ADVANCE OF NEXT SYSTEM
LATE TONIGHT INTO EARLY THURSDAY WILL ALLOW FOR SOUTHEAST WINDS IN
THE 15G20-25 KNOT RANGE FOR TONIGHT WITH SOME INDICATIONS THAT
LLWS MAY BECOME A CONCERN MAINLY OUTSIDE OF THIS FORECAST PERIOD
IN THE 06Z-12Z TIMEFRAME EARLY THURSDAY MORNING. MID AND HIGH
LEVEL CLOUDINESS TO INCREASE TODAY...WITH DETERIORATING CIGS NOT
ANTICIPATED UNTIL AFTER THIS FORECAST VALID PERIOD. SOME LIGHT
SNOW/RAIN/FREEZING RAIN CONCERNS SHOULD ALSO HOLD OFF UNTIL MAINLY
AFTER THIS FORECAST VALID PERIOD AS NEXT SYSTEM APPROACHES...WHICH
WILL NEED TO BE ADDRESSED IN GREATER DEPTH FOR THE 12Z TAFS.

&&

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

$$

SYNOPSIS...MCD
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 280110
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
810 PM EST TUE JAN 27 2015

.SYNOPSIS...
ISSUED AT 754 PM EST TUE JAN 27 2015

MOSTLY CLEAR SKIES WILL BRING TEMPERATURES DOWN INTO THE SINGLE
DIGITS AND LOW TEENS. CLOUD COVER WILL INCREASE THROUGHOUT THE DAY
ON WEDNESDAY AS THE NEXT LOW PRESSURE SYSTEM APPROACHES THE AREA.
HIGHS WILL BE IN THE UPPER 20S AND LOW TO MID 30S. EXPECT A WINTRY
MIX OF PRECIPITATION WEDNESDAY NIGHT INTO THURSDAY...WITH MINOR
ICE AND SNOW ACCUMULATIONS POSSIBLE.


&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 326 PM EST TUE JAN 27 2015

DEEP LAYERED QG SUBSIDENCE IN WAKE OF AN EXITING EAST COAST TROUGH
WILL CONTINUE TO PROMOTE QUIET/MAINLY CLEAR CONDITIONS INTO
TONIGHT/TOMORROW. ASSOCIATED SFC HIGH SETTLING SOUTH OVER THE AREA
IN TANDEM WITH MAINLY CLEAR SKIES/LIGHT WINDS WILL PRODUCE OPTIMAL
RADIATIONAL COOLING TONIGHT. AS A RESULT CONTINUED TO FAVOR COOLER
GUIDANCE FOR OVERNIGHT LOWS. RETURN SOUTHWEST FLOW BY WEDNESDAY
AFTERNOON AND JUST A GRADUAL INCREASE IN MID-HIGH CLOUDS SHOULD
ALLOW WEDNESDAY HIGHS TO RUN A FEW DEGREES WARMER THAN TODAY.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 326 PM EST TUE JAN 27 2015

INITIAL FOCUS WILL BE ON 2 WAVES THAT WILL ATTEMPT TO PHASE SOMEWHAT
ACROSS THE GREAT LAKES INTO THURSDAY. FIRST WAVE WILL BE SCOOTING
OUT OF THE PLAINS AT THE ONSET WITH WEAK CLIPPER MOVING RAPIDLY SE
OUT OF CANADA. PLAINS SYSTEM WILL HAVE A LARGE WARM TONGUE THAT WILL
ACCOMPANY IT AND MOVE INTO THE AREA WEDNESDAY NIGHT. MSTR WILL
INITIALLY BE LIMITED BUT RAPID SATURATION THROUGH 800 MB WILL TAKE
PLACE TOWARDS THURSDAY MORNING. WEDGE OF WARM AIR WILL MOVE IN
BETWEEN 800 AND 900 MB AND COMPLICATE PRECIP TYPE. WARMEST AIR WILL
BE IN PLACE AT THE ONSET WITH COOLING EFFECTS OF SATURATION AS WELL
AS APPROACH OF CANADIAN WAVE ALL LEADING TOWARDS AN EVENTUAL
TRANSITION TO COLDER PROFILES AND CHANGE OVER TO MORE SLEET/SNOW.
NOW WITH ALL THAT BEING SAID...THE BEST LIFT AND DYNAMICS WILL PASS
ACROSS THE FAR NORTHERN PARTS OF THE AREA WITH MAIN IMPACTS ACROSS
LWR MI WHERE PEAK ISENTROPIC LIFT AND FAVORABLE LOW/MID LEVEL LOW
TRACK OCCURS. GRIDS REFLECT A RATHER MESSY SETUP WITH THERMAL
PROFILES STILL HIGHLY SUSPECT CAUSING A LOW CONFIDENCE FORECAST IN
TERMS OF IMPACTS AND DURATION. SFC TEMPS WILL HOVER NEAR OR JUST
BELOW FREEZING MOST OF THE NIGHT BEFORE BEGINNING TO FALL OFF DURING
THE AFTERNOON HOURS OF THURSDAY. ANY PRECIP BY THIS TIME SHOULD
TRANSITION TO ALL SNOW WITH MAYBE A DUSTING IN SOME SPOTS.

TOUCH OF LAKE EFFECT SNOW SHOWERS WILL OCCUR THURSDAY NIGHT AS
STRONG NW FLOW SETS UP. HOWEVER...DESPITE INCREASING DELTA T`S MSTR
WILL BE ON THE DECREASE WHICH SHOULD LIMIT ANY IMPACTS AND KEEP
ACCUMULATIONS ON THE VERY LGT SIDE.

FOCUS SHIFTS TO NORTHERN AND SOUTHERN STREAM SYSTEM AND IMPACTS OVER
THE WEEKEND WITH MODELS STILL HAVING NO CLUE AS TO WHAT MAY EVOLVE.
GFS/ECMWF STILL SUGGEST DECENT CYCLOGENESIS TAKING PLACE MORE EAST
OF THE FORECAST AREA AS TROUGH TAKES ON A NEGATIVE TILT. CHANCES FOR
SOME SNOWFALL LOOK TO BE INCREASING ESPECIALLY INTO PORTIONS OF OHIO
CLOSER TO THE SUGGESTED TRACK. GIVEN TRACK RECORD OF EXTENDED MODELS
THUS FAR THIS MANY DAYS OUT...LOW CONFIDENCE ON WHAT WILL
UNFOLD...RESULTING IN A LOWERING OF BLEND OF MODEL GUIDANCE TO MID
TO HIGH CHANCE POPS FOR NOW. SYSTEM DOES HAVE THE POTENTIAL TO BRING
SEVERAL INCHES OF SNOW TO PARTS OF THE REGION SUNDAY INTO MONDAY SO
WILL NEED TO MONITOR TRENDS AND HOPE MODELS CAN COME TO SOME
AGREEMENT WITH TIME. MUCH COLDER AIR WILL FILTER IN BEHIND THE
SYSTEM WITH HIGHS IN THE SINGLE DIGITS AND TEENS ABOVE AND LOWS AT
OR BELOW ZERO.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1235 PM EST TUE JAN 27 2015

VFR WITH LIGHT WINDS EXPECTED THROUGH THE TAF CYCLE. MAY SEE A
SCT CU DECK NEAR 3 KFT MATERIALIZE FOR A BRIEF TIME THIS AFTERNOON
AS MOISTURE STREAMS OFF OF LAKE HURON UNDER A STRENGTHENING
SUBSIDENCE INVERSION. OTHERWISE ANTICIPATE SOME MID-HIGH LEVEL
CLOUDINESS...ESPECIALLY BY TOMORROW AS WAA ENSUES.


&&

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

$$

SYNOPSIS...MCD
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 280110
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
810 PM EST TUE JAN 27 2015

.SYNOPSIS...
ISSUED AT 754 PM EST TUE JAN 27 2015

MOSTLY CLEAR SKIES WILL BRING TEMPERATURES DOWN INTO THE SINGLE
DIGITS AND LOW TEENS. CLOUD COVER WILL INCREASE THROUGHOUT THE DAY
ON WEDNESDAY AS THE NEXT LOW PRESSURE SYSTEM APPROACHES THE AREA.
HIGHS WILL BE IN THE UPPER 20S AND LOW TO MID 30S. EXPECT A WINTRY
MIX OF PRECIPITATION WEDNESDAY NIGHT INTO THURSDAY...WITH MINOR
ICE AND SNOW ACCUMULATIONS POSSIBLE.


&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 326 PM EST TUE JAN 27 2015

DEEP LAYERED QG SUBSIDENCE IN WAKE OF AN EXITING EAST COAST TROUGH
WILL CONTINUE TO PROMOTE QUIET/MAINLY CLEAR CONDITIONS INTO
TONIGHT/TOMORROW. ASSOCIATED SFC HIGH SETTLING SOUTH OVER THE AREA
IN TANDEM WITH MAINLY CLEAR SKIES/LIGHT WINDS WILL PRODUCE OPTIMAL
RADIATIONAL COOLING TONIGHT. AS A RESULT CONTINUED TO FAVOR COOLER
GUIDANCE FOR OVERNIGHT LOWS. RETURN SOUTHWEST FLOW BY WEDNESDAY
AFTERNOON AND JUST A GRADUAL INCREASE IN MID-HIGH CLOUDS SHOULD
ALLOW WEDNESDAY HIGHS TO RUN A FEW DEGREES WARMER THAN TODAY.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 326 PM EST TUE JAN 27 2015

INITIAL FOCUS WILL BE ON 2 WAVES THAT WILL ATTEMPT TO PHASE SOMEWHAT
ACROSS THE GREAT LAKES INTO THURSDAY. FIRST WAVE WILL BE SCOOTING
OUT OF THE PLAINS AT THE ONSET WITH WEAK CLIPPER MOVING RAPIDLY SE
OUT OF CANADA. PLAINS SYSTEM WILL HAVE A LARGE WARM TONGUE THAT WILL
ACCOMPANY IT AND MOVE INTO THE AREA WEDNESDAY NIGHT. MSTR WILL
INITIALLY BE LIMITED BUT RAPID SATURATION THROUGH 800 MB WILL TAKE
PLACE TOWARDS THURSDAY MORNING. WEDGE OF WARM AIR WILL MOVE IN
BETWEEN 800 AND 900 MB AND COMPLICATE PRECIP TYPE. WARMEST AIR WILL
BE IN PLACE AT THE ONSET WITH COOLING EFFECTS OF SATURATION AS WELL
AS APPROACH OF CANADIAN WAVE ALL LEADING TOWARDS AN EVENTUAL
TRANSITION TO COLDER PROFILES AND CHANGE OVER TO MORE SLEET/SNOW.
NOW WITH ALL THAT BEING SAID...THE BEST LIFT AND DYNAMICS WILL PASS
ACROSS THE FAR NORTHERN PARTS OF THE AREA WITH MAIN IMPACTS ACROSS
LWR MI WHERE PEAK ISENTROPIC LIFT AND FAVORABLE LOW/MID LEVEL LOW
TRACK OCCURS. GRIDS REFLECT A RATHER MESSY SETUP WITH THERMAL
PROFILES STILL HIGHLY SUSPECT CAUSING A LOW CONFIDENCE FORECAST IN
TERMS OF IMPACTS AND DURATION. SFC TEMPS WILL HOVER NEAR OR JUST
BELOW FREEZING MOST OF THE NIGHT BEFORE BEGINNING TO FALL OFF DURING
THE AFTERNOON HOURS OF THURSDAY. ANY PRECIP BY THIS TIME SHOULD
TRANSITION TO ALL SNOW WITH MAYBE A DUSTING IN SOME SPOTS.

TOUCH OF LAKE EFFECT SNOW SHOWERS WILL OCCUR THURSDAY NIGHT AS
STRONG NW FLOW SETS UP. HOWEVER...DESPITE INCREASING DELTA T`S MSTR
WILL BE ON THE DECREASE WHICH SHOULD LIMIT ANY IMPACTS AND KEEP
ACCUMULATIONS ON THE VERY LGT SIDE.

FOCUS SHIFTS TO NORTHERN AND SOUTHERN STREAM SYSTEM AND IMPACTS OVER
THE WEEKEND WITH MODELS STILL HAVING NO CLUE AS TO WHAT MAY EVOLVE.
GFS/ECMWF STILL SUGGEST DECENT CYCLOGENESIS TAKING PLACE MORE EAST
OF THE FORECAST AREA AS TROUGH TAKES ON A NEGATIVE TILT. CHANCES FOR
SOME SNOWFALL LOOK TO BE INCREASING ESPECIALLY INTO PORTIONS OF OHIO
CLOSER TO THE SUGGESTED TRACK. GIVEN TRACK RECORD OF EXTENDED MODELS
THUS FAR THIS MANY DAYS OUT...LOW CONFIDENCE ON WHAT WILL
UNFOLD...RESULTING IN A LOWERING OF BLEND OF MODEL GUIDANCE TO MID
TO HIGH CHANCE POPS FOR NOW. SYSTEM DOES HAVE THE POTENTIAL TO BRING
SEVERAL INCHES OF SNOW TO PARTS OF THE REGION SUNDAY INTO MONDAY SO
WILL NEED TO MONITOR TRENDS AND HOPE MODELS CAN COME TO SOME
AGREEMENT WITH TIME. MUCH COLDER AIR WILL FILTER IN BEHIND THE
SYSTEM WITH HIGHS IN THE SINGLE DIGITS AND TEENS ABOVE AND LOWS AT
OR BELOW ZERO.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1235 PM EST TUE JAN 27 2015

VFR WITH LIGHT WINDS EXPECTED THROUGH THE TAF CYCLE. MAY SEE A
SCT CU DECK NEAR 3 KFT MATERIALIZE FOR A BRIEF TIME THIS AFTERNOON
AS MOISTURE STREAMS OFF OF LAKE HURON UNDER A STRENGTHENING
SUBSIDENCE INVERSION. OTHERWISE ANTICIPATE SOME MID-HIGH LEVEL
CLOUDINESS...ESPECIALLY BY TOMORROW AS WAA ENSUES.


&&

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

$$

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


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