000
FXUS63 KIWX 091524
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1024 AM EST MON DEC 9 2013

.SYNOPSIS...
ISSUED AT 1005 AM EST MON DEC 9 2013

A STRONG COLD FRONT WILL MOVE ACROSS THE REGION TODAY. LIGHT SNOW
OR FLURRIES WILL BE POSSIBLE ALONG AND AHEAD OF THE FRONT...WITH
LIGHT LAKE EFFECT SNOWSHOWERS POSSIBLE IN ITS WAKE. HIGHS TODAY
WILL BE STEADY OR SLOWING FALLING FROM THE 20S. LOWS TONIGHT WILL
DIP INTO THE LOW TO MID 20S WITH BELOW NORMAL TEMPERATURES WILL
DROP INTO THE TEENS AND SINGLE DIGITS.

&&

.UPDATE...
ISSUED AT 1005 AM EST MON DEC 9 2013

COLD FRONT MAKING ITS WAY TOWARDS THE AREA WITH OBS UPSTREAM
ACROSS N ILLINOIS SHOWING VSBYS IN THE 3 TO 5 MILE RANGE IN SOME
SPOTS. RADAR RETURNS RAPIDLY EXPANDING ACROSS THE NW HALF OF THE
FORECAST AREA WITH HIGHEST RETURNS FAR NORTH WHERE LAKE
ENHANCEMENT WILL AID SNOWFALL DEVELOPMENT. KSBN ALREADY DOWN TO 1
1/2 MILE VSBY. HAVE INCREASED POPS THROUGH 18Z AND BUMPED UP
ACCUMULATIONS A HAIR...BUT STILL KEPT UNDER AN INCH. LOCATIONS
ACROSS SE HALF WILL BE MONITORED FOR POSSIBLE INCREASE IN POPS AS
WELL OVER THE NEXT HOUR OR 2. LAKE EFFECT WILL TAKE OVER THIS
AFTERNOON WITH MAIN FOCUS ACROSS BERRIEN COUNTY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 515 AM EST MON DEC 9 2013

MUCH DRIER AIR WILL SPREAD INTO THE AREA FROM THE WEST TODAY...
ACCOMPANIED BY A STRONG COLD FRONT. INITIAL CHALLENGES INCLUDE THE
ONGOING FREEZING RAIN ADVISORY WITH PATCHY FREEZING DRIZZLE AND
FLURRIES. DECIDED TO CANCEL THE FREEZING RAIN ADVISORY GIVEN PATCHY
FREEZING DRIZZLE WITH FLURRIES...AND HANDLE IN A SPECIAL WEATHER
STATEMENT. LOW LEVEL DOWNGLIDE AND INCREASING SUBSIDENCE SHOULD HELP
END MOST OF THE PRECIPITATION BY LATE MORNING...ALTHOUGH LIGHT LAKE
EFFECT SNOW SHOWERS OR FLURRIES WILL PERSIST. GIVEN A LIMITED LAKE
FETCH WITH A WEST WIND AND INVERSION HEIGHTS BELOW 3000 FEET...KEPT
LIGHT SNOW SHOWERS LIMITED TO FAR SW LOWER MICHIGAN. TEMPERATURES
WILL RISE VERY LITTLE IF ANY AS MUCH COLDER AIR SPREADS ACROSS THE
AREA. LOWERED LOWS TONIGHT SEVERAL DEGREES GIVEN RECENT SNOW COVER
AND UPSTREAM TEMPERATURES OVER WESTERN IA FALLING BELOW ZERO.
GFS/MAV HAS BEEN TRENDING LOWS DOWN INTO THE SINGLE DIGITS...AND
APPEARS TO BE TRENDING THE RIGHT DIRECTION.

&&

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 515 AM EST MON DEC 9 2013

ARCTIC AIR MASS AND VERY COLD TEMPERATURES ALONG WITH ADDITIONAL
SYNOPTIC/LAKE EFFECT SNOW CHANCES WILL BE THE PRIMARY FORECAST
CONCERNS FOR THE LONG TERM.

TO BEGIN THE PERIOD...GUIDANCE HAS BEEN FAIRLY CONSISTENT IN
ADVERTISING NEXT MID/UPPER LEVEL TROUGH APPROACHING THE WESTERN
GREAT LAKES BY 12Z TUESDAY. STRONGEST DPVA WITH THIS FEATURE SHOULD
KEEP BULK OF SYNOPTIC SNOW CHANCES TO THE NORTH OF THE AREA. A
WEAKER SOUTHERN STREAM TROUGH SHOULD ALSO ELICIT LOW LEVEL FGEN
RESPONSE...BUT BETTER CHANCES OF THIS LIGHT SNOW SHOULD REMAIN SOUTH
OF THE FORECAST AREA EARLY TUESDAY. BACKED SOUTHWESTERLY LOW LEVEL
FLOW IN ADVANCE OF THE WESTERN GREAT LAKES SHORT WAVE SHOULD ALSO
KEEP BETTER LAKE EFFECT SNOW CHANCES TO THE NORTH OF IWX FCST AREA
THROUGH THE MORNING...WITH INCREASING CHANCES WORKING SOUTHWARD IN
THE AFTERNOON AS WINDS VEER WESTERLY BEHIND THE SFC TROUGH. A BRIEF
WINDOW LIKELY TO EXIST ON TUESDAY WITH INCREASING INSTABILITY DEPTH
AND SOME POOLING OF LOW/MID LEVEL MOISTURE FOR SOME LAKE
EFFECT/ENHANCED SNOW ACCUMULATION ESPECIALLY ACROSS NORTHERN BERRIEN
AND PERHAPS NORTHERN CASS WHERE UPSTREAM WESTERLY FETCH IS
MAXIMIZED. FOR THE REMAINDER OF THE AREA...A BREEZY/WINDY DAY
APPEARS TO BE IN STORE WITH STRONG POST FRONTAL LOW LEVEL CAA.
FOLLOWED CR ALLBLEND CONSENSUS IDEA OF SLIGHTLY LOWERING HIGHS ON
TUESDAY...BUT THIS TREND MAY NEED TO BE CONTINUED IN FUTURE
FORECASTS WITH A POSSIBILITY THAT AFTERNOON TEMPS COULD DROP BELOW
20. WIND CHILLS TUESDAY AFTERNOON ARE ALSO EXPECTED TO DROP TO
AROUND ZERO IN THE AFTERNOON WITH WEST WINDS OF 15 TO 25 MPH GUSTING
TO 30 TO 35 MPH AT TIMES.

LOWERING LAKE INDUCED EQUILIBRIUM HEIGHTS AND DRYING MID
LEVELS SHOULD TEND TO LIMIT SIGNIFICANT LAKE EFFECT ACCUMULATIONS
TUESDAY NIGHT BUT ATTENTION WILL SHIFT TO APPROACHING LOW AMPLITUDE
CLIPPER SYSTEM. GUIDANCE HAS BEEN FAIRLY CONSISTENT IN DEPICTING
BAND OF ENHANCED LOW LEVEL FRONTOGENESIS ACROSS THE SOUTHERN GREAT
LAKES REGION IN ADVANCE OF THIS SHORT WAVE AND HAVE NUDGED POPS UP
FOR THIS PERIOD...WITH LAKE EFFECT/ENHANCED SNOW CHANCES ALSO
INCREASING DURING THE WEDNESDAY/WEDNESDAY NIGHT PERIOD. BEST CHANCES
FOR LAKE EFFECT MAY BE MORE EARLY WEDNESDAY...AS STRONG MID LEVEL
DRY AIR ADVECTION SHOULD FOLLOW ON THE HEELS OF THIS CLIPPER BUT
LAKE EFFECT SNOW SHOWER CHANCES SHOULD EXTEND INTO WEDNESDAY NIGHT.
LAKE EFFECT SHOULD WIND DOWN ON THURSDAY AS FLOW DEAMPLIFICATION
ENSUES WITH MODERATING LOW/MID LEVEL THERMAL PROFILES. WEDNESDAY
NIGHT STILL APPEARS TO BE SHAPING UP AS COLDEST NIGHT OF THE PERIOD
WITH AREAS OUTSIDE OF LAKE EFFECT STRATUS LIKELY DROPPING WELL INTO
THE SINGLE DIGITS...PARTICULARLY ACROSS SOUTHWEST/SOUTHERN PORTIONS
OF THE AREA WHERE A GREATER POTENTIAL OF DECOUPLING MAY EXIST GIVEN
POSITIONING OF LOW LEVEL ANTICYCLONE TO THE WEST. SNOW COVER
EVOLUTION THROUGH MID WEEK WILL ALSO IMPACT LOWS. THURSDAY ALSO
STILL APPEARS TO BE A DAY WHERE TEMPS MAY REMAIN IN THE UPPER TEENS
MOST LOCATIONS WITH LIMITED AFTERNOON MIXING MAKING DAYTIME RECOVERY
DIFFICULT.

MEDIUM RANGE MODELS ALSO APPEAR NOW TO BE IN REASONABLE AGREEMENT IN
KICKING OUT SOUTHWEST CONUS UPPER PV ANOMALY IN THE LOWER/MID MS
VALLEY DURING THE FRIDAY/SATURDAY PERIOD WITH A PERIOD OF WAA
INDUCED PRECIP POSSIBLE. STILL SOME QUESTION AS TO IF AN ELEVATED
WARM LAYER WOULD BE ABLE TO SURVIVE EVAPORATIVE COOLING EFFECTS.
WILL KEEP PTYPES AS LIGHT SNOW AT THIS TIME BUT NOT ENTIRELY OUT OF
THE QUESTION SOME SLEET POTENTIAL COULD EXIST WITH WEAK ELEVATED
WARM LAYER. VERY FEW CHANGES MADE FOR THE THURSDAY-SUNDAY PERIOD
WITH MODERATING TEMPERATURES DURING THIS PERIOD.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 607 AM EST MON DEC 9 2013

CIGS WERE MAINLY LOW MVFR AHEAD OF A STRONG COLD FRONT AND
WEAKENING LOW LEVEL ISENTROPIC LIFT. SOME LIGHT FREEZING DRIZZLE
IS POSSIBLE...AND MAY INCLUDE THIS MENTION BRIEFLY IN THE EARLY
FEW HOURS OF THE SBN AND FWA TAFS. WINDS SHOULD CONTINUE FROM THE
WEST...WITH CONDITIONS BECOMING VFR BY LATE IN THE DAY AS MUCH
DRIER AIR SPREADS ACROSS NRN INDIANA BEHIND THE COLD FRONT.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...GALE WATCH FROM TUESDAY MORNING THROUGH TUESDAY EVENING FOR
     LMZ043-046.

     SMALL CRAFT ADVISORY UNTIL 9 AM EST TUESDAY FOR LMZ043-046.

&&

$$

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


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