Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 192121 AFDILN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 421 PM EST WED NOV 19 2014 .SYNOPSIS... A COLD FRONT WILL PUSH EAST ACROSS THE AREA TONIGHT...BRINGING A FEW SNOW SHOWERS AND A REINFORCING SHOT OF COLD AIR. HIGHS THURSDAY AND FRIDAY WILL BE WELL BELOW NORMAL. INCREASING SOUTHERLY WINDS WILL ALLOW FOR A WARMING TREND THROUGH THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... GOOD WAA TODAY HAS ALLOWED TEMPERATURES TO MOVE UP ABOVE FREEZING ACROSS THE AREA. HOWEVER...A MID LEVEL SHORT WAVE ROTATING THROUGH THE SOUTHERN GREAT LAKES WILL HELP PUSH A COLD FRONT EAST ACROSS THE AREA TONIGHT. AN AXIS OF BETTER LOW LEVEL CONVERGENCE WILL WORK EAST WITH THE FRONT THIS EVENING INTO THE OVERNIGHT HOURS. MOISTURE IS FAIRLY SHALLOW BUT THERE MAY BE ENOUGH FORCING TO PRODUCE SOME ISOLATED TO POSSIBLY SCATTERED SNOW SHOWERS. WE COULD THEN SEE A FEW FLURRIES LINGER THROUGH MUCH OF THE REST OF THE NIGHT AS WE GET INTO SOME DECENT CAA AND CYCLONIC FLOW BEHIND THE FRONT. SOUTHWEST FLOW AHEAD OF THE FRONT WILL LEAD TO SOME NON DIURNAL TEMPERATURES INTO THIS EVENING...ESPECIALLY ACROSS THE EAST. OVERNIGHT LOWS WILL RANGE FROM THE TEENS IN THE NORTHWEST TO THE LOWER 20S IN THE SOUTHEAST. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... CYCLONIC LOW LEVEL FLOW AND CONTINUED WEAK CAA SHOULD ALLOW FOR SOME LINGERING STRATOCUMULUS INTO THE DAY ON THURSDAY. TOUGH TO RULE OUT A FEW FLURRIES TOO...ESPECIALLY ACROSS OUR NORTHEAST. OTHERWISE...SURFACE HIGH PRESSURE WILL BUILD EAST ACROSS THE REGION THURSDAY AFTERNOON INTO FRIDAY. THIS WILL ALLOW FOR DECREASING CLOUDS BY THURSDAY NIGHT AND MOSTLY SUNNY SKIES ON FRIDAY. THE SURFACE HIGH SHOULD BE CENTERED OVER US BY 12Z FRIDAY MORNING. ASSUMING WE CLEAR OUT THURSDAY NIGHT...EXPECT GOOD RADIATIONAL COOLING...ESPECIALLY IN AREAS WITH LINGERING SNOW COVER. WILL GO AHEAD AND UNDERCUT GUIDANCE A FEW DEGREES...RANGING LOWS FROM THE SINGLE DIGITS NORTHWEST TO THE MID TEENS SOUTHEAST. HIGHS ON THURSDAY WILL BE WELL BELOW NORMAL...RANGING FROM THE LOW/MID 20S NORTH TO NEAR 30 SOUTH. A FAIR AMOUNT OF SUN ON FRIDAY WILL ALLOW FOR SLIGHTLY WARMER TEMPERATURES BUT READINGS WILL STILL BE WELL BELOW NORMAL. INCREASING SOUTHWESTERLY FLOW WILL LEAD TO DEVELOPING WAA/ISENTROPIC LIFT FRIDAY NIGHT. THIS WILL RESULT IN INCREASING CLOUDS AND PERHAPS A FEW SHOWERS MOVING IN FROM THE SOUTHWEST LATE. ASSUMING THE CLOUDS HOLD OFF LONG ENOUGH...TEMPERATURES WILL LIKELY FALL OFF EARLY FRIDAY EVENING AND THEN SLOWLY RISE THROUGH THE OVERNIGHT HOURS. HOWEVER...SURFACE TEMPS WILL STILL BE BELOW FREEZING SO ANY PCPN WOULD LIKELY FALL AS AT LEAST A MIX OF FREEZING RAIN GIVEN THE WARMER AIR MOVING IN ALOFT. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... FOCUS IN THIS PERIOD WILL BE THE VERY DEEP LOW PRESSURE SYSTEM TO DEVELOP VIA PHASING MID/UPPER LEVEL SHORTWAVE TROUGHS LATE IN THE WEEKEND IN THE MISSISSIPPI VALLEY AND WESTERN GREAT LAKES. CHANGEABLE TEMPERATURES...GUSTY WINDS...AND HIGH PROBABILITY OF SHOWERS IS EXPECTED AROUND THIS SYSTEM. AT 12Z SATURDAY MORNING....STRONG ARCTIC HIGH PRESSURE /1032 MB/ WILL HAVE PUSHED SOUTHEAST INTO THE CAROLINAS WITH RETURN FLOW/WARM ADVECTION REGIME WELL ESTABLISHED OVER THE OHIO VALLEY ALOFT. DECOUPLED BOUNDARY LAYER/WEAK SURFACE FLOW MEANS THAT SURFACE TEMPS LIKELY BE NEAR OR BELOW FREEZING AS WARM/MOIST ADVECTION IS RAMPING UP. ALOFT...A POTENT SOUTHERN STREAM SHORTWAVE TROUGH WILL BE ACROSS WRN TEXAS AND A SLIGHTLY WEAKER SHORTWAVE IN BRITISH COLUMBIA IN THE NRN STREAM. ON SATURDAY MORNING...THE WARM/MOIST ADVECTION ALOFT /ISENTROPIC ASCENT/ WILL LEAD TO GRADUAL MOISTENING ESPECIALLY ALONG/WEST OF I-71 WHERE FCST SOUNDINGS /19.12Z NAM...GFS...GFSP...ECMWF/ ALL SUGGEST ENOUGH LOW/MID LEVEL MOISTURE FOR LIGHT/SCATTERED PRECIP DVLPMENT. ELEVATED WARM LAYER > 5C SUGGESTS COMPLETE HYDROMETEOR MELTING THUS ANYTHING REACHING THE GROUND /VERY LIGHT/ WOULD BE FREEZING RAIN OR RAIN...THERE IS SOME UNCERTAINTY ON HOW QUICKLY THE BOUNDARY LAYER WILL WARM FRIDAY NIGHT/SATURDAY MORNING. RIGHT NOW AM NOT SEEING ENOUGH DEPTH/BREADTH OF THE VERTICAL MOTION TO SUGGEST A WIDESPREAD TRAVEL ISSUE...BUT SOMETHING THAT WILL NEED TO BE WATCHED IN THE EARLY MORNING HOURS BEFORE THE WARM ADVECTION DEEPENS AND ALL RISE ABOVE FREEZING LATER SAT MORNING. ON SATURDAY NIGHT/SUNDAY...DEEPENING SHORTWAVE IN THE NRN STREAM AS IT CROSSES ALBERTA/SASK BEGINS TO STEER DEEPENING SRN STREAM WAVE IN THE ARKLATEX MORE NNEWD WITH RAPID PHASING OF THE STREAMS TO OCCUR BY SUNDAY NIGHT. BY MONDAY MORNING...ANOMALOUS/DEEP CLOSED LOW WILL BE OVER MN AS A RESULT OF THIS PROCESS. AT THE SURFACE...AMALGAM OF DETERMINISTIC RUNS /GFS...GFSP...ECMWF...CMC...AS WELL SOME EXPERIMENTAL DATA/ ALL INDICATE A DRAMATIC PRESSURE FALL AND DEEPENING OF THE SFC LOW ATTENDANT TO THE SRN STREAM SHORTWAVE...WITH A SUB 980MB CYCLONE NEAR CHICAGO/MADISON BY LATER SUNDAY NIGHT. THIS OPENS UP THE GULF BY SUNDAY AS STRONG SHORTWAVE DYNAMICS CROSS THE AREA. CONTINUED HIGH RAIN CHANCES AND MAY NEED TO CONSIDER ADDING THUNDER IN THE SOUTH ABOVE THE RELATIVELY STABLE NEAR-SURFACE LAYER GIVEN DYNAMICS/NON-ZERO ELEVATED INSTBY. OCCLUSION TO RAPIDLY TAKE PLACE INTO MONDAY WITH COLD FRONT CROSSING THE AREA MONDAY MORNING. CONTINUED HIGHER RAIN CHANCES WITH DIMINISHING TREND THEREAFTER...THEN DRY MIDWEEK. TEMPS WILL BE A SOURCE OF POTENTIAL SIGNIFICANT ERROR IN THE FCST GIVEN SEVERAL INSTANCES OF NON-DIURNAL/ADVECTION DRIVEN TEMP RISES/FALLS. KEPT TEMPS COOL SATURDAY WITH MAINLY A SSELY FLOW AND WEAKER VERTICAL MIXING...THIS IS NOT A GOOD WARMING WIND DIRECTION FOR OUR AREA ESP WITH PLENTY OF CLOUDS. ALLOWED FOR CONTINUED RISE IN TEMPS SAT NIGHT THROUGH SUNDAY....TIGHTENED THE DIURNAL RANGE QUITE A BIT THESE DAYS. ALLOWED FOR STEADY/FALLING TEMPS ON MONDAY IN WAKE OF COLD FRONTAL PASSAGE. BY TUES/WED...TEMPS BACK WELL BELOW NORMAL /30S AND LOWER 40S/ AMIDST STRONG COLD ADVECTION. ALSO INCREASED WINDS OVER BLENDED GUIDANCE GIVEN SUB 980MB CYCLONE TO OUR WEST. MAY NEED TO GO HIGHER STILL ESPECIALLY SUNDAY/SUNDAY NIGHT/MON MORNING. && .AVIATION /20Z WEDNESDAY THROUGH MONDAY/... STRONG SOUTHWEST FLOW HAS DEVELOPED ON THE BACK SIDE OF RETREATING SFC HIGH PRESSURE. SW WINDS WILL GUST UP TO 30 KTS THRU THE AFTN. EXPECT TO SEE VFR CONDITIONS THRU THE AFTN WITH MVFR CIGS DEVELOPING THIS EVENING WITH THE APPROACH AND PASSAGE OF A COLD FRONT. A FEW SNOW SHOWERS OR FLURRIES WILL DEVELOP THIS EVENING AND THEREFORE HAVE INCLUDED A MENTION OF VCSH OR P6SM -SHSN. MVFR CIGS WILL PERSIST THROUGH MOST OF THE NIGHT DUE TO STRONG COLD AIR ADVECTION AND CYCLONIC FLOW BEHIND THE FRONT. EXPECT SOME IMPROVEMENT WITH CIGS RISING INTO VFR CATEGORY VERY LATE TONIGHT/TOWARD SUNRISE. VFR CIGS BETWEEN 3500 AND 5000 FEET ARE EXPECTED THURSDAY. WINDS WILL GENERALLY BE FROM THE WEST AT 10 TO 15 KTS TONIGHT AND SW AROUND 15 KNOTS WITH GUSTS AS HIGH AS 25 KTS ON THURSDAY. OUTLOOK...MVFR CIGS POSSIBLE SUNDAY AND MONDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...JGL NEAR TERM...JGL SHORT TERM...JGL LONG TERM...BINAU AVIATION...AR

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