Area Forecast Discussion
Issued by NWS Northern Indiana

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556
FXUS63 KIWX 072000
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
300 PM EST SUN FEB 7 2016

.SYNOPSIS...
ISSUED AT 1234 PM 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...(THIS EVENING THROUGH MONDAY)
ISSUED AT 300 PM EST SUN FEB 7 2016

UPPER TROUGH OVER THE UPPER MIDWEST WILL DIG SE INTO THE EASTERN US
TONIGHT-MONDAY IN RESPONSE TO WEST COAST RIDGE AMPLIFICATION. AT THE
SFC...997 MB LOW NEAR DULUTH MN WILL BROADEN SE INTO LOWER MI
FORCING A CDFNT THROUGH ON LEADING EDGE OF EXTREME HEIGHT FALLS EAST
TONIGHT. THE RESULT WILL BE A TREND TOWARD COOLER TEMPS AND CHANCES
FOR PRECIPITATION.

FIRST OPPORTUNITY FOR A LIGHT RAIN/SNOW MIX WILL COME THIS EVENING
INTO THE EARLY OVERNIGHT MAINLY ALONG/EAST OF INTERSTATE 69 AS
INCREASING UPPER DIVERGENCE AND STRONG MID LVL DCVA ENHANCE LOW-MID
LEVEL CONVERGENCE ALONG SFC FRONT ONCE REACHING OHIO. HELD POPS IN
CHANCE RANGE HERE GIVEN INITIAL FIGHT WITH DRY AIR IN LOWEST 10 KFT.
ONSET OF PCPN (IF IT DEVELOPS) WOULD LIKELY BE RAIN GIVEN WARM NEAR
SFC LAYER...AND THEN TRANSITION TO A BRIEF RAIN/SNOW MIX (LITTLE TO
NO ACCUMULATION) LATE EVENING/OVERNIGHT BEFORE ENDING.

MONDAY WILL FEATURE SCATTERED TO NUMEROUS SNOW SHOWERS AS DEEPER
MOISTURE/SATURATION OVERSPREADS UNDER CLOSED MID LVL CIRCULATION.
ASSOCIATED SECONDARY PV PUSH/CDFNT WITH LAPSE RATES STEEPENING UNDER
COLD POCKET ALOFT COULD ALLOW FOR BRIEF HEAVIER SQUALLS WHICH COULD
LAY DOWN A QUICK DUSTING TO HALF INCH. ROADS FOR THE MOST PART
SHOULD BE IN DECENT SHAPE GIVEN MARGINAL SFC TEMPS.

&&

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 300 PM EST SUN FEB 7 2016

AN EXTENDED STRETCH OF BELOW NORMAL TEMPS AND LONG DURATION LAKE
ENHANCED/EFFECT SNOW EVENT MONDAY NIGHT THROUGH THURSDAY THE PRIMARY
FOCUS THROUGH THE EXTENDED...

MODELS REMAIN IN GOOD AGREEMENT IN LOW LEVEL CIRCULATION/TROUGH
EDGING SLOWLY EAST OVER THE EASTERN GREAT LAKES MONDAY NIGHT THROUGH
WEDNESDAY...WITH CONTINUED COLD ADVECTION IN NW FLOW (850 MB TEMPS
-10C MONDAY NIGHT TO -18C WEDNESDAY) AND AMPLE BACKGROUND MOISTURE
TO SET UP A PROLONGED NW FLOW LAKE ENHANCED/EFFECT SNOW EVENT.
IMPRESSIVE MOISTURE DEPTH TO 15 KFT AND 20-25 KNOTS WITHIN 925-800
MB LAYER SHOULD FAVOR GOOD INLAND PENETRATION OF LAKE ENHANCED SNOW
SHOWERS LATER MONDAY NIGHT THROUGH EARLY WEDNESDAY. LIMITING FACTOR
FOR HEAVIER SNOWFALL RATES/RATIOS AT LEAST INITIALLY (LATE MONDAY
NIGHT-TUESDAY) WILL BE SOMEWHAT MARGINAL DELTA T/S AND BETTER
OMEGA/HIGHER THETA-E LAPSE RATES TAKING PLACE JUST BELOW THE DGZ.
THIS OVERLAP AND RESULTING POTENTIAL FOR MORE IMPRESSIVE
BANDING/HIGHER RATIOS BECOMES MORE FAVORABLE BY TUESDAY NIGHT-
WEDNESDAY AS LAKE-700 MB DIFFERENTIALS PUSH WELL INTO THE 20S. A
LONG DURATION ADVISORY WILL LIKELY BE NEEDED FOR AT LEAST ST JOE
IN/CASS MI/BERRIEN COUNTIES LATER MONDAY NIGHT THROUGH
WEDNESDAY...WITH LIGHTER ACCUMS/IMPACTS TO TRAVEL ANTICIPATED WELL
INLAND. DRIER POLAR AIR AND BACKING WINDS/LOWERING INVERSION HEIGHTS
SHOULD ALLOW FOR LAKE EFFECT SNOW TO WIND DOWN INTO LATER WEDNESDAY-
THURSDAY AS EASTERN LAKES SYSTEM FINALLY LIFTS OUT.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1234 PM EST SUN FEB 7 2016

VFR CONDITIONS EXPECTED THROUGH THE FIRST HALF OF THE TAF PD.
GUSTY SW WINDS THIS AFTERNOON WILL SUBSIDE THIS EVENING AS A LOW
PRESSURE SYSTEM TRACKS SOUTHEAST THROUGH THE GREAT LAKES REGION.
ANTICIPATING DETERIORATING CONDITIONS TOWARDS THE END OF THE
PERIOD...WITH STRONG CAA/SATURATING BOUNDARY LAYER BRINGING SCT
-SHSN AND MVFR CONDS. THINKING THERE WILL BE PERIODS OF IFR
CONDITIONS AFTER 09Z...ESPECIALLY AT KSBN...HOWEVER CONFIDENCE ON
THE LOWER SIDE ATTM WITH EXACT TIMING. THEREFORE...INTRODUCED MVFR
CONDS AT BOTH TERMINALS LATER IN THE PERIOD.

&&

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

$$

SYNOPSIS...FISHER/NG
SHORT TERM...STEINWEDEL
LONG TERM...STEINWEDEL
AVIATION...NG


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