Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 250538
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1238 AM EST WED FEB 25 2015

.SYNOPSIS...
ISSUED AT 316 PM EST TUE FEB 24 2015

AN ARCTIC FRONT WILL BRING GUSTY WINDS...SCATTERED SNOW SHOWERS
AND COLDER TEMPERATURES TO THE REGION. OVERNIGHT LOWS WILL DROP
INTO 5 TO 10 ABOVE ZERO RANGE WITH HIGHS ON WEDNESDAY IN THE MID
TEENS TO LOWER 20S.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 316 PM EST TUE FEB 24 2015

BAND OF LIGHT TO MODERATE SNOW WAS PERSISTING ACROSS FAR NW PORTIONS
OF THE AREA WHERE VISIBILITIES HAVE DROPPED LOCALLY TO UNDER A MILE
AT TIMES. REPORTS COMING IN OF DRIFTING ON MANY ROADS IN THE
ADVISORY AREA AND EVEN FURTHER SOUTH BUT THUS FAR ACTUAL BLOWING
SNOW HAS BEEN SOMEWHAT LIMITED WITH WINDS GENERALLY HOLDING UNDER 30
MPH (OCCASIONAL GUST 35 TO 40 MPH BUT NOT LONG ENOUGH TO CAUSE SIG
PROBLEMS). INCREASED POPS FURTHER SOUTH REMAINDER OF THE AFTERNOON
AS HIGH RES MODELS SHOW CURRENT BAND DRIFTING FURTHER SOUTH AND
IMPACTING DOWN TO AT LEAST PARTS OF THE US 30 CORRIDOR. WITH
DRIFTING IN MANY AREAS AND POCKETS OF BLOWING SNOW OPTED FOR
SIMPLER AREA OF BLOWING SNOW FOR ALL LOCATIONS THROUGH 00Z. TEMPS
COULD POSE A CHALLENGE OVER THE NEXT COUPLE OF HOURS AS DECENT
WARMING OCCURRING BETWEEN THE TROUGH AXIS AND MAIN COLD FRONT
DROPPING THROUGH WISCONSIN. PARTS OF NORTHERN ILLINOIS NOW
APPROACHING FREEZING WITH MID TO UPPER 20S MAKING A RUN FOR WESTERN
COUNTIES. WITH LOSS OF DAYTIME HEATING...THINK THE WARMEST WILL
REMAIN AWAY FROM THE AREA BUT HAVE NUDGED UP TEMPS A TOUCH IN THE
WEST NEXT COUPLE OF HOURS WHERE SUN HAS POKED THROUGH.

MAIN ARCTIC BOUNDARY WILL DROP IN LATE AFTERNOON/EARLY EVENING WITH
SCATTERED SNOW SHOWERS ACCOMPANYING IT. MOST LOCATIONS WILL SEE
LITTLE IMPACT BUT ANYONE GETTING UNDER THE SNOW SHOWERS WILL SEE
VISIBILITIES BELOW A MILE AND POSSIBLE QUITE A BIT LOWER FOR A
PERIOD. HAVE EXPANDED CHC POPS INLAND MORE FOR THE EVENING TO COVER
THE POTENTIAL BUT LIMITED SE EXTENT.

LIMITED LAKE RESPONSE THIS EVENING AS DELTA T`S APPROACH MID TEENS
BUT A LOT OF DRY AIR LOOKS TO BE ENTRAINED. HAVE INCREASED SOMEWHAT
IN FAR NW BUT STILL HELD WITH CHC FOR NOW...RAPIDLY DECREASING AFTER
9Z. DRY CONDITIONS LOOK TO BE IN STORE FOR WEDS WITH HIGHS IN THE
MID TEENS TO LOWER 20S.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 316 PM EST TUE FEB 24 2015

SNOW CHANCES WEDNESDAY NIGHT/THURSDAY AND AGAIN ON SUNDAY INTO
MONDAY...ALONG WITH ANOTHER BLAST OF ARCTIC TEMPERATURES IN
BETWEEN...REMAINS THE FOCUS OF THE LONG TERM PERIOD.

POTENT BUT SHEARING NORTHERN STREAM WAVE WILL BE DIVING EAST
SOUTHEAST THROUGH THE GREAT LAKES LATE WEDNESDAY NIGHT AND THURSDAY.
LIGHT SNOW WILL OVERSPREAD THE AREA EARLY THURSDAY MORNING.
CONTINUED TREND FOR WARMER MIN TEMPS WEDNESDAY NIGHT W/ RAPID
INCREASE IN CLOUD COVER EXPECTED. WEAK FORCING/ASCENT AND INITIAL
DRY LAYER CENTERED AROUND 850MB WILL YIELD LITTLE MORE THAN FLURRIES
INTO THE EARLY PART OF THE OVERNIGHT...HOWEVER NOTED AN OVERALL
FASTER TREND WITH ONSET OF PRECIP/SHEARING WAVE PASSAGE. SUBTLE
HEIGHT FALLS AND OVERALL WEAKER ASCENT SHOULD KEEP SNOW LIGHT
THROUGH THE DAY...AS SYSTEM EXITS EAST OUT OF THE AREA DURING THE
AFTERNOON INTO EVENING HOURS. FORECAST SNOW AMOUNTS ARE GENERALLY
LESS THAN AN INCH THROUGH THIS PERIOD.

YET ANOTHER ARCTIC INTRUSION IS EXPECTED THURSDAY NIGHT AS
SFC HIGH CENTER SLIDES SOUTHEAST ALONG THE LEE OF THE NORTHERN
ROCKIES INTO THE GREAT LAKES/OHIO VALLEY BY FRIDAY NIGHT. 850MB
TEMPS DROPPING TO -20C THURSDAY NIGHT SHOULD YIELD MODEST LAKE
RESPONSE...HOWEVER BACKGROUND NORTH/NORTHEASTERLY FLOW SHOULD KEEP
BEST LAKE EFFECT SNOW CHANCES WEST OF THE FORECAST AREA THURSDAY
NIGHT THROUGH FRIDAY. CONTINUED A DOWNWARD TREND IN MIN TEMPS
THURSDAY NIGHT OUTSIDE OF LAKE EFFECT CLOUD COVER. WITH SFC RIDGE
EXPECTED DIRECTLY OVER THE REGION FRIDAY NIGHT...SIGNIFICANT
RADIATIONAL COOLING EXPECTED AND HAVE ACCOUNTED FOR THIS WITH A
LOWERING OF MIN TEMPS FRIDAY NIGHT...SEVERAL DEGREES LOWER THAN 12Z
SUPERBLEND.

EJECTION OF SWRN CONUS TROF ENERGY WILL BRING PRECIP CHANCES SUNDAY
INTO MONDAY. LATEST 12Z GUIDANCE CONTINUES TO SHOW A MORE
SOUTHERLY/SUPPRESED SNOWFALL TRACK AS STRONG NORTHERN STREAM VORT
SWINGS EAST ACROSS THE NORTHERN GREAT LAKES. OWING TO LATEST
TRENDS...THERMODYNAMIC PROFILES SUPPORT ALL FROZEN PRECIP...SO
REMOVED RAIN MENTION FOR SOUTHERN HALF OF THE FORECAST AREA SUNDAY
AFTERNOON.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1238 AM EST WED FEB 25 2015

DRY SURFACE COLD FRONT WILL CROSS THE AREA DURING THE NEXT FEW
HOURS. FORECAST SOUNDINGS AND MOS GUIDANCE STILL SUGGEST A BRIEF
PERIOD OF HIGH END MVFR CEILINGS POSSIBLE AT KSBN IMMEDIATELY
BEHIND THE FRONT GIVEN QUICK SHOT OF BOUNDARY LAYER COOLING AND
MOISTURE FLUX FROM LAKE MICHIGAN. DRY AIR ADVECTION SHOULD
SCATTER LOW CLOUDS BY LATE MORNING THOUGH AND VFR CONDITIONS
EXPECTED THROUGH THE REST OF THE DAY. NEXT CHANCE OF LIGHT SNOW
AND REDUCTION IN FLIGHT CATEGORY LOOKS TO BE JUST OUTSIDE THIS TAF
FORECAST PERIOD...AS A WEAK AND MOISTURE STARVED SHORTWAVE SWINGS
THROUGH THE REGION.

&&

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

$$

SYNOPSIS...FISHER
SHORT TERM...FISHER
LONG TERM...NG
AVIATION...AGD


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