000
FXUS63 KIWX 121748
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1248 PM EST THU DEC 12 2013

.SYNOPSIS...
ISSUED AT 1034 AM EST THU DEC 12 2013

HIGH PRESSURE WILL MOVE SOUTHEAST OF THE AREA LEAVING VERY COLD
AIR IN ITS WAKE. HIGHS TODAY WILL ONLY BE IN THE TEENS. THE
AIRMASS OVER THE AREA WILL BEGIN TO MODERATE TONIGHT WITH LOWS
REMAINING IN THE TEENS. SLIGHTLY WARMER TEMPERATURES CAN BE
EXPECTED FRIDAY WITH HIGHS NEAR 30.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 426 AM EST THU DEC 12 2013

INITIAL CHALLENGES ARE WITH THE WIND CHILL TEMPERATURES EARLY THIS
MORNING. ISSUED AN ADVISORY UNTIL 13Z/8 AM EST GIVEN BITTERLY COLD
CONDITIONS DEVELOPING OVERNIGHT. TEMPERATURES HAD FALLEN BELOW ZERO
AT SEVERAL LOCATIONS OVER NRN INDIANA...WITH THE WIND CHILL DOWN TO
-24 AT VPZ. UPSTREAM CLOUDS WERE RACING SOUTHEAST AND WILL REACH THE
WESTERN SECTIONS BY DAYBREAK...BUT NOT FAST ENOUGH TO PREVENT
WIDESPREAD TEMPERATURES FROM REACHING BETWEEN -5 AND -10 DEGREES AS
SNOW COVER AND INITIALLY CLEAR SKIES ALLOW EARLY MORNING
TEMPERATURES TO PLUMMET. OTHERWISE...WARM AIR ADVECTION WILL BEGIN
LATER TODAY AS WINDS BACK TO THE SOUTHWEST ON THE BACK SIDE OF THE
SURFACE HIGH PRESSURE AREA. GIVEN CURRENT MODEL OUTPUT
INITIALIZATION AND VERIFICATION...WENT WITH THE COLDER GFS MAV WITH
TEMPERATURES REACHING ONLY INTO THE TEENS TODAY.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 426 AM EST THU DEC 12 2013

...SIGNIFICANT SNOW ACCUMULATIONS LIKELY FRI NIGHT-SAT...

ACTIVE NOAM FLW REGIME CONTS THIS PD AND HIGHLITED BY EJECTING
POTENT SRN STREAM SW NR SAN DIEGO THIS AM. THIS SYS WILL EDGE EWD
AND OPEN OVR THE FOUR CORNERS TONIGHT AND THEN LIFT OUT NEWD INTO
THE OH VALLEY ON SAT AHD OF POTENT ARCTIC STREAM SW DROPPING INTO
THE NRN LAKES. FAIRLY CONGRUENT LG SCALE CONSENSUS REMAINS AND
SIMILAR IN SCOPE TO LAST NIGHTS 00Z CONSENSUS TAKING HFC FM SE MO
FRI NIGHT AND INTO ERN OH SAT AFTN. WHILE DIFFS REMAIN W/EWD
AMPLITUDE OF MID LVL TROUGH...COASTAL HANDOFF DECIDEDLY SLWR AND
FITS W/ISENTROPIC PROGS CARRYING ACCUMULATING SNOW FURTHER INTO SAT
AFTN. STGR SOLUTIONS ALOFT FVRD ATTM GIVEN SAT DEPICTION AND XPCD
WKNG DOWNSTREAM CONFLUENCE ALTHOUGH DETAIL DIFFS AT THIS JUNCTURE
ARE ADMITTEDLY SMALL FOR AN EVENT AT THIS TIME RANGE. ROEBBER SNOW
RATIO PROBABILITIES TIED TO CONSENSUS BLENDED QPF OF ONE QUARTER
INCH NW CORNER TO ONE HALF IN SE CORNER PORTENDS A GENERAL 3 TO 6
INCH SNOW. HWVR AS STATED YDA UPSIDE POTENTIAL CAN NOT BE IGNORED
W/POTENTIAL FOR BAND OF 6 TO 8 INCHES ALG/S OF A WINIMAC...COLUMBIA
CITY...WAUSEON LINE. THUS GIVEN INCREASING LIKELIHOOD OF SIG SNOW
THAT WILL NO DOUBT IMPACT HOLIDAY SHOPPING WILL ISSUE A WINTER STORM
OUTLOOK LTR THIS MORNING.

MUTED LK RESPONSE FOLLOWS SAT NIGHT AS DEPTH OF ARCTIC STREAM WAVE
HAD DAMPENED CONSIDERABLY. LL THERMAL TROUGH WHILE SEASONABLY
INTENSE SAT NIGHT FLEETING W/CONSIDERABLE SUBSIDENT DRYING IN WAKE
OF SRN STREAM LEFTOVER. SECONDARY CLIPPER DIVES THROUGH THE LAKES LT
MON W/PD OF LIGHT SNOW MON NIGHT.

AFT THAT SIG UNCERTAINTY DVLPS W/POTENTIAL DEMISE OF ERN NOAM LW
TROUGH AND GENERALLY DOUBT LATEST EC DISLODGING ENTRENCHED COLD
AIRMASS FULLY OUT AND PLAINLY ILLUSTRATED BY EC/MEX MOS DIVIDE IN
EXCESS OF 20 DEGREES BY DY7. WILL HOLD W/ALL BLEND NOD FOR NOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1247 PM EST THU DEC 12 2013

VFR CONDITIONS TO START THE PERIOD WITH SOME UNCERTAINTY
REGARDING CIGS TONIGHT AND FRIDAY MORNING. MID AND HIGH CLOUDS
GRADUALLY MOVING OFF TO SOUTHEAST WITH PARTIAL CLEARING OCCURING
AT TAF SITES EARLY THIS AFTERNOON. LAKE CLOUDS SEEN ON SATELLITE
DROPPING SOUTH TOWARD KBEH AT 1730Z WITHIN THERMAL TROUGH. THIS
TROUGH NOT PROGGED TO REACH KSBN AS IT SLOWLY MIGRATES EAST.
HOWEVER...LOW LEVEL WIND FIELD BECOMES WNW FOR A PERIOD WHICH MAY
ALLOW CLOUDS TO DRIFT TOWARD KSBN. MODEL SOUNDINGS ALSO SHOWING
INCREASING LOW LEVEL MOISTURE AROUND 00Z WITH THESE TRAJECTORIES.
FOR NOW DO NOT HAVE ENOUGH CONFIDENCE FOR MVFR OR IFR CONDITIONS
AT KSBN OVERNIGHT SO STAYED VFR WITH INTRODUCTION OF SOME SCT015
CLOUDS. WEAK FRONTAL BOUNDARY TO SAG NEAR KSBN FRI AM WITH WEAK
WINDS AND MOISTURE TRAPPED BENEATH INVERSION WITH WARM AIR
ADVECTION ALOFT. THIS LEADS TO A LITTLE HIGHER CONFIDENCE IN MVFR
CIGS DEVELOPING DURING THE DAY ALONG WITH MODEL GUIDANCE SO ADDED
MVFR CONDITIONS. KFWA TO REMAIN VFR THROUGH THIS PERIOD WITH
DETERIORATING CONDITIONS EXPECTED LATER FRIDAY AND ESPECIALLY
FRIDAY NIGHT ALL AREAS WITH SNOW DEVELOPING.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LMZ043-046.

&&

$$

SYNOPSIS...KG
SHORT TERM...SKIPPER
LONG TERM...T
AVIATION...LASHLEY


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