Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 270255
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
955 PM EST MON JAN 26 2015

.SYNOPSIS...
ISSUED AT 542 PM EST MON JAN 26 2015

OTHER THAN SOME LIGHT SNOW IN THE WEST TONIGHT...WEATHER WILL
REMAIN QUIET THROUGH MID WEEK. LOWS TONIGHT WILL RANGE FROM 7
TO 22 DEGREES. HIGHS ON WEDNESDAY WILL BE IN THE UPPER 20S AND
30S. SKIES WILL BE PARTLY TO MOSTLY CLOUDY.

&&

.UPDATE...
ISSUED AT 951 PM EST MON JAN 26 2015

NR TERM EXPANSION OF -SN/FZDZ ACRS NE IL AND PLETHORA OF ACCIDENT
REPORTS HAS PROMPTED THE ISSUANCE OF A WINTER WX ADVISORY ACRS
FAR SW INCLUDING WHITE AND PULASKI COUNTIES. CONTD LWRG OF CIG
HGTS AND NARROWING SFC TD DEPRESSIONS OVR NW IN SUGGESTS SFC
PRECIP IMMINENT FAR SW ALG LL BAROCLINIC ZONE. WHILE SIG ICING NOT
XPCD SHRT TERM HIGHRES GUIDANCE SUGGESTING UPWARD OF .05 INCH
LIQUID EQUIVALENT PSBL W/MUCH OF THAT IN FORM OF FZDZ. THUS GIVEN
TIMING AND SFC TEMPS IN THE MID/UPR 20S GLAZING LIKELY.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 325 PM EST MON JAN 26 2015

AREA OF SHEARED CYCLONIC VORTICITY EMBEDDED WITHIN THE LEFT EXIT
REGION OF A 140 KT 3H JET WILL CONTINUE TO DROP INTO THE MID
MS/WESTERN OH VALLEYS THIS EVENING INTO THE EARLY OVERNIGHT. A
NARROW BAND OF -SN ORIENTED NW TO SE ACROSS WI-IL (AS OF 20Z) ALONG
THE ASSOCIATED FGEN INDUCED CIRCULATION/TIGHTENING THERMAL GRADIENT
MAY CLIP OUR FAR WSW WITH A LIGHT COATING OF SNOW DURING THIS TIME.
LIMITING FACTOR FOR ANYTHING MORE THAN A MID CHC POP HERE WILL BE A
PRONOUNCED LOW LEVEL DRY WEDGE WITH MUCH BETTER CHANCES JUST WEST OF
THE IWX CWA. DRY OUTSIDE OF A FEW FLURRIES OTHERWISE TONIGHT.

STRONG SUBSIDENCE/RAPID HEIGHT RISES WITH WEAK CONVERGENCE/PCPN
SETTLING WELL SOUTH SHOULD ENSURE A DRY TUESDAY AS WESTERN/CENTRAL
LAKES LOW LEVEL RIDGING BECOMES RE-ESTABLISHED. CLOUD COVER REMAINS
THE MAIN UNCERTAINTY WITH SIG MID LVL DRYING HOPEFULLY ALLOWING FOR A
N-S CLEARING TREND. WILL TREND TOWARD PARTLY CLOUDY WORDING FOR NOW
IN HOPE THAT BOUNDARY LAYER STRATOCU THINS/BREAKS UP.
OTHERWISE...ONLY MINOR TWEAKS MADE TO TEMPS.

&&

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 421 PM EST MON JAN 26 2015

SFC HIGH EXPECTED TO MOVE ACROSS THE CWA TUE NGT. STRONG RADIATIONAL
COOLING WITH NEARLY CLEAR SKIES/LIGHT WINDS/SNOW COVER SHOULD
COMPENSATE FOR WK WAA ON BACKSIDE OF SFC HIGH AND UPR RIDGE BUILDING
IN... LOWERED GOING FCST MINS A FEW DEGREES TO RANGE FROM UPR TEENS
WEST... TO UPR SINGLE DIGITS EAST WHERE LESS CLOUDS/MORE SNOW COVER
EXPECTED. BETTER RESPONSE TO WAA EXPECTED WED AS LOW PRESSURE MOVES
EAST FROM THE CENTRAL PLAINS INCREASING MIXING.... HIGHS FCST TO
RANGE FROM THE U20S EAST TO THE M30S WEST.

SHRTWV APCHG PAC NW/SW CANADA TODAY KICKING OUT CUT-OFF LOW WEST OF
BAJA. THESE TWO SYSTEMS EXPECTED TO PHASE OVER THE MIDWEST THU. TOP
DOWN SATURATION EXPECTED IN OUR AREA WED NGT AS THIS SYSTEM
APPROACHES. WARM LAYER ALOFT SHOULD RESULT IN LIQUID PRECIP BUT
EVAPORATIONAL COOLING MAY KEEP PRECIP PREDOMINANTLY SNOW IN PORTIONS
OF THE AREA... MAINLY NORTH. A PERIOD OF FREEZING RAIN ALSO PSBL.

FOR THE REST OF THE PERIOD...ANOTHER STRONG NORTHERN STREAM SYSTEM
WILL DROP SOUTH INTO THE MAIN LONGWAVE TROF OVER CENTRAL NORTH
AMERICA. GIVEN THE SUPERIOR ECMWF HANDLING WITH THE PAST SYSTEM...HAVE
REJECTED THE GFS/MOS HEAVY SNOW SUNDAY. KEPT A CHANCE FOR SNOW
SATURDAY NIGHT AND SUNDAY...HOWEVER...CONFIDENCE IS LOW WITH THIS
SYSTEM.  OTHERWISE...TEMPERATURES WILL BE MUCH BELOW NORMAL FRIDAY
THROUGH TUESDAY AS NORTHWEST FLOW ALOFT CONTINUES WITH CROSS POLAR
FLOW. CONCERN FOR BITTERLY COLD AIR REACHING THE FORECAST AREA AGAIN
WITH ECMWF 850 MB TEMPS NEAR -40C OVER HUDSON BAY SATURDAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 812 PM EST MON JAN 26 2015

SHEARING SW ACRS IL DROPPING THROUGH WRN PERIPHERY OF DEEP H5 LW
TROUGH WILL STEER ASSOCD -SN/FZDZ WELL WEST OF THE TERMINALS
OVERNIGHT AS SURFACE CYCLONE BOMBS OUT OUT ACRS THE WRN ATL.
THUS XPC VFR CIGS TO PERSIST THIS PD W/LIGHT GRADIENT FLW CONTG
WITHIN SFC RIDGE AXIS.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...FREEZING RAIN ADVISORY UNTIL 6 AM EST TUESDAY FOR INZ013-020.

MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

UPDATE...T
SYNOPSIS...MCD
SHORT TERM...STEINWEDEL
LONG TERM...SKIPPER
AVIATION...T


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