Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 290551 AFDILN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 1251 AM EST THU JAN 29 2015 .SYNOPSIS... A COLD FRONT WILL APPROACH TONIGHT AND MOVE THROUGH THE REGION ON THURSDAY. THIS SYSTEM WILL BRING A THREAT OF WINTRY PRECIPITATION AT LEAST AT THE ONSET IN SOME LOCATIONS. AS THE LOW PRESSURE SYSTEM DEPARTS...ANY LINGERING SHOWERS SHOULD TURN TO SNOW SHOWERS FROM LATE THU AFTERNOON INTO THURSDAY EVENING. HIGH PRESSURE WILL BEGIN TO BUILD BACK INTO THE AREA ON FRIDAY AND REMAIN IN CONTROL OF THE WEATHER INTO THE START OF THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... CONDITIONS ARE DRY INITIALLY DUE TO HIGH PRESSURE THAT WILL BEGIN TO DEPART THE REGION. HIGH CLOUDS ARE THICKENING AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. IT STILL APPEARS THAT TEMPERATURES WILL GENERALLY BE STEADY DURING THE EVENING HOURS WITH GUIDANCE SUGGESTING MIN TEMPERATURES AROUND MIDNIGHT IN MANY LOCATIONS OUTSIDE OF ANY DECOUPLED VALLEYS IN EASTERN AND SOUTHEAST PART OF THE CWA. SOUTHERLY FLOW WILL INCREASE TONIGHT. AS SOUTHERLY FLOW INCREASES TEMPERATURES WILL BEGIN TO SLOWLY RISE THROUGH THE OVERNIGHT HOURS. PRECIPITATION WILL HOLD OFF FOR MOST OF THE OVERNIGHT HOURS. THERE IS ENOUGH CONCERN FOR SOME OF THIS TO REACHING THE GROUND TOWARD DAWN THAT A FREEZING RAIN ADVISORY IS PLANNED FOR THE NORTHERN TIER OR TWO OF COUNTIES...THOUGH MOST OF THIS SHOULD HOLD OFF UNTIL THE SHORT TERM PERIOD. && .SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/... IN THE SW PART OF THE AREA...EXPECT TEMPERATURES TO ALREADY BE NEAR OR ABOVE FREEZING TO START THE PERIOD AND THE PRECIPITATION WILL LIKELY JUST BEGIN AS RAIN. HOWEVER...THERE IS SOME UNCERTAINTY WITH THE TIME OF ARRIVAL OF PRECIPITATION AS THE GFS SATURATES THIS AREA A BIT QUICKER AND THE TOP DOWN APPROACH WOULD SUGGEST THE POSSIBILITY OF A MIX AT ONSET THERE AS WELL. THE CHANCES FOR A MIX AT ONSET ARE BETTER FURTHER TO THE NORTH AND EAST AS THE INITIALLY DRY AIRMASS WILL BE ABLE TO WET BULB AND FREEZING RAIN OR SLEET WOULD BE POSSIBLE FOR A LONGER PERIOD OF TIME...BUT THIS PRECIPITATION WOULD BE VERY LIGHT. IN THIS AREA...THERE WILL BE A BRIEF WINDOW FOR A COUPLE OF HOURS WHERE TEMPERATURES COULD BE AT OR JUST BELOW FREEZING AS PRECIPITATION MOVES INTO THE AREA. DUE TO THIS...A BRIEF PERIOD OF FREEZING RAIN WILL BE POSSIBLE CONSIDERING THE COLD AND INITIALLY FROZEN OR SNOW COVERED GROUND IN PLACE PARTICULARLY ACROSS THE NORTH AND NORTHEASTERN PART OF THE AREA DUE TO THE RECENT COLDER WEATHER. ANY PRECIPITATION THAT REACHES THE GROUND BEFORE MID MORNING IN THE FAR NORTH AND EAST COULD LEAD TO SOME IMPACTS OF SLICK OR ICY SPOTS ON UNTREATED OR SECONDARY ROADS...BRIDGES...OVERPASSES AND WALKWAYS DURING THE MORNING...SO A FREEZING RAIN ADVISORY HAS BEEN ISSUED FOR THE NORTHERN TIER OR TWO OF COUNTIES TO INCLUDE THE COLUMBUS METRO AREA. ANY FREEZING RAIN IS EXPECTED TO BE LIGHT...BUT STILL A POTENTIAL THREAT. AS FOR THE HWO...WE PLAN TO CONTINUE TO MENTION FREEZING RAIN OR MIX AT ONSET FOR THE SOUTHWEST THREE QUARTERS OF THE AREA. WARMER AIR WILL CONTINUE TO SURGE INTO THE AREA BY MID TO LATE THURSDAY MORNING AND AS IT DOES TEMPERATURES WILL RISE ABOVE FREEZING ACROSS THE ENTIRE FA AHEAD OF THE COLD FRONT. THIS COLD FRONT MOVE THROUGH THE FA DURING THE AFTERNOON AND EARLY EVENING HOURS ON THURSDAY BRINGING ADDITIONAL PRECIPITATION CHANCES TO THE AREA. AS THE COLDER AIR BEGINS TO WORK INTO THE REGION LATER IN THE AFTERNOON AND EVENING...PRECIPITATION WILL CHANGEOVER TO SNOW SHOWERS FROM NORTH OR NORTHEAST TO SOUTHEAST. THE CHANCES FOR LIGHT SNOW SHOWERS WILL CONTINUE THURSDAY NIGHT AND POSSIBLY INTO EARLY ON FRIDAY DUE TO A COMBINATION OF A WEAK DISTURBANCE PASSING THROUGH AND WINDS OFF OF LAKE MICHIGAN. SNOWFALL ACCUMULATION FROM THIS IS STILL EXPECTED TO LIGHT AND AN INCH OR LESS. HIGH PRESSURE WILL BEGIN TO WORK INTO THE FA LATER FRIDAY AFTERNOON INTO FRIDAY NIGHT. CLOUD COVER WILL DECREASE THROUGH THE NIGHT FRIDAY NIGHT AND WINDS WILL BE LIGHT. WITH THIS COMBINATION EXPECT TEMPERATURES TO DROP DOWN INTO THE SINGLE DIGITS TO THE TEENS ACROSS THE FA. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... SURFACE HIGH PRESSURE PASSING NW TO SE OVER THE REGION AT THE START OF THE PERIOD WILL PROVIDE CLEAR TO PARTLY CLOUDY SKIES AND COLD TEMPERATURES FRIDAY NIGHT AND SATURDAY. AFTER THIS...THE FORECAST TROUBLES BEGIN. AN UPPER LEVEL TROUGH ABOUT TO MOVE ONSHORE ON THE WEST COAST WILL CLOSE OFF A LOW OVER THE SW CONUS LATE IN THE WEEK. AN UPPER LEVEL IMPULSE SHOULD THEN DROP SE OUT OF CANADA ACROSS THE GREAT PLAINS THIS WEEKEND. THE DEGREE TO WHICH THIS PHASES WITH THE UPPER LOW/RESIDUAL TROUGH OVER THE SW CONUS IS STILL UNCERTAIN. THE EVENTUAL TRACK AND STRENGTH OF THE UPPER LEVEL SYSTEM WILL AFFECT SUBSEQUENT SURFACE LOW DEVELOPMENT IN THE EASTERN CONUS. A WIDE RANGE OF TRACKS AND STRENGTHS OF SURFACE SYSTEMS HAS BEEN OBSERVED IN THE MODELS IN RECENT DAYS...WITH THE GFS AND ECMWF SHOWING BOTH RUN TO RUN AND MODEL TO MODEL INCONSISTENCIES...AND NO CONSENSUS YET. THE LATEST 12Z RUNS HAVE GENERALLY TRENDED WEAKER WITH THE SYSTEM. BOTTOM LINE...THERE IS STILL A LARGE DEGREE OF UNCERTAINTY REGARDING THE FORECAST DURING THIS PERIOD. AT THIS POINT THE FORECAST IS STILL ONE OF LOW CONFIDENCE...AND IS BASED ON A BLEND OF RECENT MODEL RUNS. THE PRECIP THREAT WILL BE FROM SATURDAY NIGHT INTO SUNDAY NIGHT...AND MAINLY IN THE FORM OF SNOW. HAVE ALLOWED FOR A POTENTIAL MIX WITH RAIN IN SOUTHERN OH AND NORTHERN KY. IN THE WAKE OF THE WEEKEND SYSTEM...HIGH PRESSURE WITH ANOTHER ARCTIC AIR MASS IS EXPECTED TO MOVE IN FROM THE NW AND DOMINATE THROUGH TUESDAY. ON WEDNESDAY...ANOTHER LARGE SCALE UPPER TROUGH BEGINS TO DEEPEN AS IT MOVES IN FROM THE NW...AND LOW LEVEL WARM AIR ADVECTION BEGINS IN ADVANCE OF IT. TIMING OF WEAK UPPER LEVEL IMPULSES IN THAT TIME FRAME WOULD BE A GUESS AT THIS POINT...BUT SOME MODEL RUNS HAVE SHOWN A POTENTIAL FOR A BIT OF SNOW...AND HAVE USED A 20 PERCENT POP ON WEDNESDAY. && .AVIATION /06Z THURSDAY THROUGH MONDAY/...
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VFR CONDITIONS WILL PREVAIL THROUGH THE EARLY PART OF THE TAF PERIOD. SHOWERS FALLING OUT OF A MID DECK WILL SPREAD INTO THE REGION AROUND 12Z AND QUICKLY MOVE THROUGH WITH A CHANCE OF PRECIPITATION FOR ONLY A COUPLE OF HOURS AT ANY ONE LOCATIONS. WILL BE A CLOSE CALL...BUT LATEST HIGH RESOLUTION GUIDANCE SUGGESTS THAT TEMPERATURES WILL BE JUST RISING ABOVE FREEZING AS PRECIPITATION MOVES THROUGH. WHILE TAFS ONLY MENTION RAIN...THERE STILL IS A CHANCE OF FREEZING RAIN AT ALL BUT THE CINCINNATI TERMINALS. ONCE THIS BAND OF PRECIPITATION MOVES THROUGH EXPECT WINDS TO BECOME GUSTY. MVFR CEILINGS WILL MOVE IN AHEAD OF A COLD FRONT. EXPECT FRONTAL PASSAGE BETWEEN 18Z AND 22Z. WINDS WILL VEER TO THE WEST AND REMAIN GUSTY WITH CEILINGS LOWER A BIT FURTHER. CANNOT RULE OUT A FEW SHOWERS WITH THE FRONT BUT PROBABILITY DOES NOT LOOK TOO HIGH SO ONLY INCLUDED VCSH. WINDS WILL DIMINISH A BIT AFTER 00Z WITH A SLIGHT IMPROVEMENT IN CEILINGS. OUTLOOK...MVFR CEILINGS WILL LIKELY CONTINUE THROUGH FRIDAY. IFR CEILINGS AND VISIBILITIES LIKELY SUNDAY INTO SUNDAY NIGHT WITH MVFR CONDITIONS POSSIBLY CONTINUING INTO MONDAY.
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&& .ILN WATCHES/WARNINGS/ADVISORIES...
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OH...FREEZING RAIN ADVISORY FROM 4 AM TO 11 AM EST THIS MORNING FOR OHZ026-034-035-043>046-052-054>056-065. KY...NONE. IN...NONE.
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&& $$ SYNOPSIS...JP NEAR TERM...CONIGLIO SHORT TERM...JP LONG TERM...HAL AVIATION...

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