Area Forecast Discussion
Issued by NWS Northern Indiana

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414 FXUS63 KIWX 061056 AFDIWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 556 AM EST SAT FEB 6 2016 .SYNOPSIS... ISSUED AT 523 AM EST SAT FEB 6 2016 COLDER AIR AND SNOW SHOWERS WILL DOMINATE THE UPCOMING WORK WEEK WITH MANY LOCATIONS SEEING ACCUMULATING SNOWFALL MONDAY THROUGH AT LEAST WEDNESDAY. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 523 AM EST SAT FEB 6 2016 UPPER LEVEL TROUGH WILL QUICKLY MOVE THROUGH TODAY. LITTLE IN THE WAY OF DEEP MOISTURE BEING SEEN WITH MAINLY MID/HIGH CLOUDS AND A FEW POCKETS OF STRATUS/GROUND FOG. MORE EXTENSIVE CLOUD DECK WILL MOVE IN THIS MORNING TO BRING PARTLY TO MOSTLY CLOUDY SKIES. BULK OF DEEPEST MOISTURE AND ANY LIGHT PRECIP POTENTIAL SHOULD REMAIN NORTH OF THE AREA. SKIES WILL BEGIN TO CLEAR THIS AFTERNOON MAINLY SE...ALLOWING FOR TEMPS TO CLIMB TO NEAR OR JUST ABOVE 40. CLOUDS MAY LINGER LONGER IN NORTHERN AREAS WHICH WILL KEEP HIGHS IN THE MIDDLE TO UPPER 30S. UPPER LEVEL RIDGING WILL CONTINUE WITH LOW LEVEL FLOW CONTINUING TO PUMP IN SOMEWHAT WARMER AIR. AS ONE TROUGH LEAVES TO THE EAST ANOTHER WILL QUICKLY MOVE IN FROM THE WEST LATER TONIGHT...MAINLY INCREASING CLOUD COVER ONCE AGAIN. && .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 523 AM EST SAT FEB 6 2016 TRIPLE ULVL JETLETS ON ORDER OF 140-180KTS PUNCH THROUGH NORTHERN PERIPHERY OF GRADUALLY EXPANSION OF WRN CONUS RIDGE TODAY THROUGH MONDAY...CULMINATING IN EXTREME AMPLITUDE TROF BASE ACROSS SOUTHERN GREAT LAKES BY 12 UTC TUE WITH SLIGHT NEG TILT INTO SOUTHWARD DROPPING POLAR ORIGIN VORTEX. THIS SETUP SHOULD AID IN LONGEVITY OF SURFACE REFLECTION/LAKE AGGREGATE TROFFING THAT BODES WELL FOR MULTI DAY LES EVENT. IN MEANTIME...PRE SYSTEM WAA SUNDAY WITH MODEST MID LEVEL THETA-E TONGUE THAT IS INITIALLY MORE DOWNSTREAM DISPLACED OF DEEPENING SYSTEM. NOTABLE HIGH SUB CLOUD CONDENSATION PRESSURE DEFICITS SUGGEST LITTLE PROB OF MSRB QPF. CONTD MIX MENTION AS NEAR SURFACE SNOW MELT RATE HIGH WITH SHALLOW SFC BASED WARM TW. SYSTEM ACCELERATION INTO SUNDAY NIGHT SUGGESTS INCREASING CHCS/AMOUNTS ACROSS EASTERN CWA AS REFLECTED IN POPS/QPF. HAVE GREATLY REDUCED SNOW ACCUMS HOWEVER ESPECIALLY EASTERN CWA WHERE PROLONGED MIX/WET GROUND TO OFFSET ACCUMS ESPECIALLY PRIOR TO 06 UTC MON. SUCCINCT MID LEVEL WRAPPED CVA/RESPECTABLE MOISTURE CURL IMPINGING ON CWA BY DAYBREAK MON COULD BRING BURSTS OF ACCUMULATING SNOW FOR MON AM COMMUTE. EXTREME CAA PLUS DYNAMIC COOLING EFFECTS/PROLONGED MID LVL HEIGHT FALLS TO QUICKLY TRANSITION TO ALL SNOW EARLY MON AM. ADDITIONALLY HAVE LOWERED MAX TEMPS ON MON AS DIURNAL RANGE TO REMAIN WELL SQUELCHED. RAISED POPS FOR MON SANS TIMING THOUGH UPWARD NUDGE TO 12-18 UTC ACCUMS OVER PRIOR IN ATTEMPT TO AFFORD HINT OF TEMPORAL RESOLUTION. LOW STATIC STABILITY COULD PORTEND TO MESOBETA/GAMMA BANDED ENHANCEMENTS THOUGH AT DY3 BEYOND SCOPE OF MORE THAN PASSING MENTION FOR NOW. AS LES SETUP RAMP CONSIDERABLY MONDAY NIGHT SYNOPYIC MOISTURE ENHANCEMENT TO AID IN DGZ DEPTH THOUGH AT PRESENT MODEL PROFILES LACK EXTREME SUPERSATURATION. HEIGHT OF LES EVENT/LAKE INDUCED PARAMETERS TUE INTO EARLY TUE NIGHT. FOR NOW HAVE CONTINUED TRENDS OF RAISING POPS SIG IN LES FAVORED AREA MIDWEEK...WITH SIMILAR ALBEIT TRAILING INDICATIONS IN SLR/ACCUMS GIVEN MESOSCALE CONDITIONALS. SUSPECT LONG DURATION ADV TO BE CONSIDERED IN FUTURE. EVENTUALLY MIDATL CYLCLOGENESIS LENDS LYSIS OF LAKE AGGREGATE TROF WITH GRADUAL DIMINISHING MOISTURE DEPTH/LK EQL WITH A MORE SHALLOW DGZ EXTENDING INTO SUBCLOUD REGION FOR LESSER ACCUM RATES WED/THU. CONTD HINTS OF CLIPPER SYSTEM FRI WITH SOME LAKE RESPONSE THEREAFTER. HOWEVER EXPECT RESPONSE NOT AKIN TO LATEST GIVEN RAPID SOUTHEAST OVERTAKE OF ARCTIC RIDGE INTO SAT. EC STILL HINTING AT STRONG SOUTHERN STREAM SYSTEM ABOUT VALETINES DAY WITH SURFACE LOW TRACK INTO OHIO VALLEY. NORTHWARD MOISTURE FLUX/OPEN GOMEX ATOP ARCTIC AIRMASS WILL NEED TO BE MONITORED FOR POSSIBLE SIG SYNOPTIC SNOW EVENT...WITH CAVEAT OF A SLOWER/MORE NORTHERN TRACK AFFORDING POTENTIAL ICE SWATCH. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 553 AM EST SAT FEB 6 2016 LITTLE MORE THAN HIGH CLOUDS HAS ALLOWED BOTH TAF SITES TO DROP INTO MVFR RANGE DUE TO HAZE/FOG AS LOW LEVEL MOISTURE SLOWLY INCREASES. ANY FOG SHOULD QUICKLY DISSIPATE SHORTLY AFTER 12Z WITH HIGH CLOUDS DOMINATING THE SKIES THROUGH AT LEAST THIS EVENING BEFORE CEILINGS SLOWLY BEGIN LOWERING IN ADVANCE OF THE NEXT SYSTEM. WINDS WILL BECOME SOUTHWESTERLY WITH TIME AND REMAIN AROUND 10 KNOTS THROUGH THE PERIOD. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...FISHER SHORT TERM...FISHER LONG TERM...MURPHY AVIATION...FISHER VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

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