Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 081054
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
554 AM EST MON FEB 8 2016

.SYNOPSIS...
ISSUED AT 424 AM EST MON FEB 8 2016

ACCUMULATING SNOWFALL IS EXPECTED ACROSS MUCH OF THE GREAT LAKES
THROUGH AT LEAST THURSDAY. AMOUNTS DURING ANY ONE PERIOD WILL BE
GENERALLY LIGHT...BUT THE LONG DURATION OF THE EVENT MAY ALLOW
AREAS NEAR LAKE MICHIGAN TO SEE BETWEEN 6 AND 12 INCHES OF SNOW
BY THE TIME THURSDAY MORNING ARRIVES. A BLAST OF ARTIC AIR IS
POISED TO IMPACT THE REGION BY THE WEEKEND WITH AFTERNOON HIGHS
STRUGGLING THROUGH THE TEENS AND LOWS IN THE SINGLE DIGITS.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 424 AM EST MON FEB 8 2016

PRIMARY FOCUS FROM NEAR TERM THROUGH WED NIGHT IS TO DELAY ONSET OF
PRIMARY LES EVENT OWING TO SLOW SWRN GRTLKS FUJIWHARA WITH CONSERTED
COLD POOL PLUNGE DLAD. INITIAL SHEARED ENVIRONMENT AND MODEST
DIFFERENTIALS TO PROVIDE SOME LAKE ENHANCEMENT OF SYNOPTIC
MOISTURE/ARCTIC FRONTAL SHSN WITH EPISODIC WAVES OF ENHANCED
DEFORMATION/DCVA EMANATING FROM THE UPPER MS VLY REGION. UNTIL
180 KT ULVL JET PRESENTLY TOPPING RIDGE/FAR NRN BC DRIVES SWD
TOWARDS LWR MO VALLEY ON TUE WILL LES INGREDIENTS TO CONGEAL. LAKE
EFFECT CAPE AND LAKE INDUCED EQL APPEAR BROADLY RAMPED WITH
RESPECT TO TIME AND PEAK ON ORDER OF 400 J/KG AND 13 KFT WED AFT
RESPECTIVELY. ANTICIPATE A FEW LES BANDS TO BECOME WELL
ESTABLISHED AND PERSIST TUE NIGHT INTO WED...IF NOT INTO FIRST
HALF WED NIGHT BEFORE DOWNTURN STARTS. TOTAL ACCUMS ESTABLISH WELL
WITHIN RANGE OF MULTIMODEL COBB AVERAGES WITH/WITHOUT COMPACTION
AND CLOSE TO OR SLIGHTEST UPWARD NUDGE OVER PRIOR FORECASTS AND
CONSISTENT WITH TRENDS.

&&

.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 424 AM EST MON FEB 8 2016

DEEP UPPER LEVEL TROUGH WILL BEGIN TO FINALLY PULL AWAY FROM THE
AREA. NW FLOW WILL PERSIST THROUGH AT LEAST THE FIRST HALF OF
THURSDAY WITH HIGH CHC TO LIKELY POPS WARRANTED FOR LIGHT QPF/ACCUMS
AS DELTA T`S IN THE MID 20S. ALIGNMENT OF DGZ AND BEST LIFT WILL NOT
BE FULLY MESHED BUT STILL ENOUGH TO HOLD ONTO HIGHER POPS THAN
DEPICTED BY SUPERBLEND OF MODELS.

LOW LEVEL FLOW AND THERMAL CONTRIBUTIONS WILL BECOME MORE
CHALLENGING AFTER THURSDAY WITH REGARDS TO SFC TEMPERATURES AS WELL
AS LAKE EFFECT POTENTIAL. MED RANGE MODELS CONSISTENT WITH REGARDS
TO -28 TO -34 C CORE OF 850 TEMPS ACCOMPANYING DEEP UPPER LOW.
HOWEVER...WHERE THIS WILL END UP IS LESS CERTAIN. 12Z RUNS OF GFS
AND ECMWF WERE MORE TOWARDS THE NE STATES. 00Z GFS HOLD WITH THIS
IDEA, BUT 00Z ECMWF BRINGS CORE OF COLD AIR INTO THE EASTERN GREAT
LAKES. AT THIS POINT...WILL MAINTAIN PREVIOUS IDEA OF SLGT CHC TO
CHC POPS CLOSER TO THE LAKE. ENOUGH CONFIDENCE IN COLDER TREND TO
LOWER TEMPS A FEW DEGREES FRI INTO SAT. IF CORE OF COLDER AIR DOES
COME FURTHER WEST...THEN A SIGNIFICANT DROP IN TEMPS WILL BE
WARRANTED.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 547 AM EST MON FEB 8 2016

HIGH CONFIDENCE IN DETERIORATING FLIGHT CONDITIONS THROUGH THE
PERIOD WITH THE GREATEST IMPACTS OCCURRING TONIGHT AND BEYOND.
MVFR CONDITIONS WILL OCCUR THROUGH MUCH OF THE DAY AS SNOW SHOWERS
AFFECT BOTH SITES. A GREATER CONCENTRATION OF SNOW SHOWER
ACTIVITY AS WELL AS TREND TOWARDS POTENTIAL IFR CONDITIONS WILL
TAKE PLACE AFTER 6Z TUES. FURTHER CHANGES IN TAFS WILL BE NEEDED
AS SITUATION UNFOLDS.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 1 AM TUESDAY TO 10 AM EST THURSDAY FOR
     LMZ043-046.

&&

$$

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


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