Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 070941
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
441 AM EST SUN FEB 7 2016

.SYNOPSIS...
ISSUED AT 434 AM EST SUN FEB 7 2016

ONE MORE DAY OF ABOVE NORMAL TEMPERATURES IS IN STORE FOR THE
REGION BEFORE MORE WINTER LIKE CONDITIONS DOMINATE THE UPCOMING
WEEK. ACCUMULATING SNOWFALL WILL BE SEEN ACROSS THE ENTIRE REGION
OVER THE UPCOMING WEEK WITH THE HEAVIEST AMOUNTS EXPECTED CLOSER
TO LAKE MICHIGAN.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 434 AM EST SUN FEB 7 2016

MODELS GENERALLY IN CONSENSUS ON HANDLING OF FEATURES THAT WILL
IMPACT THE REGION INTO MUCH OF THE LONG TERM PERIOD. SFC LOW WILL
DROP EAST-SOUTHEAST OUT OF MANITOBA INTO VCNTY OF NORTHERN LK
MI/EASTERN UP OF MICHIGAN BY 12Z SUNDAY. GIVEN THE FAR NORTHERLY
TRACK AND INCREASING LOW LEVEL RESPONSE IN WINDS ONE MORE DAY OF
ABOVE NORMAL TEMPERATURES WILL BE IN STORE WITH HIGHS CLIMBING
INTO THE 40S DESPITE INCREASING CLOUD COVER. FORCING WILL INCREASE
AHEAD OF PRE FRONTAL TROUGH WITH INFLUX OF HIGHER THETA E AIR TO
ALLOW FOR SATURATION OF LOW LEVELS TO COMMENCE. HOWEVER...CONCERNS
REMAIN THAT THIS MAY NOT OCCUR PRIOR TO THE TROUGH DEPARTING THE
FORECAST AREA. BEST CHANCE...IF IT CAN OCCUR...WILL BE GENERALLY
ALONG/EAST OF I-69 WHERE SLGT CHC TO CHC POPS REMAIN WARRANTED
TONIGHT. PTYPE IN THIS AREA REMAINS SOMEWHAT QUESTIONABLE AS
MODELS DO DIFFER ON HOW FAST LOW LEVEL THERMAL PROFILES COOL. GFS
MORE AGGRESSIVE ON COLD AIR ARRIVAL THAN NAM. HAVE OPTED FOR A
BLEND TO KEEP WITH A RAIN/SNOW MIX THROUGH 6Z MON AND THEN ALL
SNOW (IF ANY PRECIP IS LEFT IN THE EAST) THEREAFTER.

WHILE MOISTURE PROFILES WILL REMAIN NEARLY SATURATED IN BETWEEN
DEPARTING TROUGH AND MAIN PUSH OF COLD AIR...LIFT WILL BE MINIMIZED
FOR A PERIOD WHICH MAY RESULT IN LITTLE MORE THAN FLURRIES OR EVEN A
BRIEF DRY PERIOD PRIOR TO ARRIVAL OF MORE WIDESPREAD SNOW SHOWERS
TOWARDS 12Z MON. HAVE PLACED EITHER A MENTION OF FLURRIES OR CHC
SNOWSHOWERS EVERYWHERE AFTER 6Z MON TO COVER POTENTIAL FOR NON
MEASURABLE SNOWFALL. BY THE 9 TO 12Z MON WINDOW...POPS HAVE BEEN
RAMPED UP TO MID TO HIGH CHC AS LIFT RAPIDLY INCREASES IN THE WEST.

&&

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 434 AM EST SUN FEB 7 2016

EXTREME 160 TO MORE THAN 200 M/12 HR HEIGHT FALL ANOMALY TO DIG FROM
EASTERN ND INTO LOWER MID OHIO VALLEY BY MONDAY MORNING.  ONLY SEE
SLIGHT DELAY WITH RESPECT TO TIMING OF ASSERTIVE DCVA ONSLAUGHT
COINCIDENT WITH RESPECTABLE MID LVL MOISTURE ALONG SECONDARY
WRAPPED ARCTIC INTRUSION TO PROVIDE SUBSTANTIAL LOW LEVEL
FRONTOGENETIC FORCING. FEATURE COLLOCATED WITH LEADING EDGE
ISALLOBAIC GRADIENT/LOW STATIC STABILITY THROUGH ABOUT 10KT...AS
TYPICAL/MODEST 50-80 J/KG SBCAPE AXIS SWEEPS EASTWARD THROUGH CWA
FROM ABOUT 15 UTC MON THROUGH EVENING. FAVORABLE SPIKE IN SNOWSQUALL
PARAMETER /BANACOS ET AL./ POINTS TO FAVORABLE THERMODYNAMIC/
KINEMATIC INGREDIENTS FOR THE POTENTIAL FOR A HIGH IMPACT/SUB
ADVISORY/HIGH POP/LOW QPF/ACCUM EVENT ASSOCIATED WITH SQUALLY/LINEAR
BANDED SEGMENTS. FOR RIGHT NOW SAVING GRACE MAY BE INITIAL WARM/WET
SURFACE TEMPS AND SLIGHT DELAY THAT MORE SO BRIDGES GAP BETWEEN
AM/PM COMMUTE TIMES. AS EXPECTED LINGERING MID LEVEL SYSTEM MOISTURE
HAS LED TO NOTABLE UPTICK IN DGZ LAYER SUPERSATURATION OVER PAST 24
HRS. INITIAL CBL SHEAR FOR MULTI BAND INITIALLY LIKELY TRANSFORMING
INTO FEWER/MORE SUCCINCT THERMAL CIRCULATIONS INTO TUE/TUE NIGHT.
AGAIN AT SOME POINT MULTI-PERIOD ADVISORY WILL BE NEEDED...BUT MORE
TIME TO ALLOW FURTHER MODEL SHIFTS/INT. PEAK EVENT TIMEFRAME APPEARS
TO BE TUE AFTN/EARLY TUE NIGHT AS OPTIMAL OVERLAP OF DEEP
SUPERSATURATED DGZ/MODERATELY STRONG LAKE INDUCED THERMODYNAMICS
WITH LK INDUCED EQL NEAR STEADY AROUND 8KFT AND LK BASED CAPE
INCREASES FROM ABOUT 200 TO 400 J/KG. WHILST LATER IN EVENT EVEN
THOUGH A STEADY INCREASE IN THERMODYNAMIC CHARACTERISTICS
CONTINUE...SUSPECT SLR AND TOTAL QPF STUNTED BY DWINDLING/LOWERING
DGZ/DIMINISHED BULK MOISTURE WITHIN FIRMLY ESTABLISHED ARCTIC
AIRMASS/INTRODUCTION OF PLATES/COLUMNS ABOUT 3-4KFT LEVEL. TOTAL
DURATION OF EVENT THROUGH 00 UTC THU SUGGESTS 8 PLUS INCHES ACROSS
NORTHERN BERRIEN/NWRN CASS COUNTIES AS GOOD INITIAL ATTEMPT TO
NUMERIC CONTEXT TO EVENT. CAVEAT FOR EVEN MORE EXTREME AMOUNTS MAY
BE THE DELAY IN LOWER GREAT LAKES ENERGY TRANSFER TO COASTAL SYSTEMS
WITH INCREASE IN MULTI-MODEL SURFACE PRESSURE REFLECTIONS EXHIBITING
A LAGGARDLY TWO TO THREE PART PARTIAL HANDOFF WITH LAKE AGGREGATE
TROF REMAINING STAUNCH INTO LATE WED/EARLY THU.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1235 AM EST SUN FEB 7 2016

HIGH CLOUDS WILL MOVE EAST ACROSS BOTH TAF SITES OVER THE NEXT
SEVERAL HOURS IN ADVANCE OF THE NEXT SYSTEM. CIGS WILL SLOWLY
LOWER THROUGH THE PERIOD BUT SHOULD POSE LITTLE IN THE WAY OF
IMPACTS UNTIL OUTSIDE THE VALID PERIOD. INCREASED MIXING OF
STRONGER LOW LEVEL WINDS WILL BRING WIND GUSTS TO AROUND 20 KTS
UNTIL PASSAGE OF PRE FRONTAL TROUGH LATE AFTERNOON INTO EARLY
EVENING.


&&

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

$$

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


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