Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 220540 AFDILN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 140 AM EDT TUE APR 22 2014 .SYNOPSIS... A COLD FRONT WILL MOVE THROUGH THE AREA LATE TONIGHT INTO TUESDAY MORNING. HIGH PRESSURE WILL THEN BUILD IN FOR THE MIDDLE OF THE WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AREA OF LIGHT SHRA IS WORKING ACROSS WRN PORTIONS OF THE FA ATTM. THE HRRR...AND THE NAM TO SOME EXTENT...HAS PICKED UP ON THIS AND THEY MOVE THIS FEATURE THRU THE AREA IN THE NEXT SEVERAL HOURS. ANOTHER ROUND OF SHOWERS AND MAYBE AN ISOLATED RUMBLE OF THUNDER WILL THEN MOVE THRU THE REGION AFTER MIDNIGHT JUST AHEAD OF THE APPROACHING COLD FRONT. KEPT THE OVERNIGHT LOWS FROM THE PREVIOUS SHIFT ALONE...FROM THE LOWER 50S IN THE NW TO THE UPPER 50S SOUTHEAST. && .SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/... THE COLD FRONT WILL PUSH THROUGH THE REMAINDER OF THE REGION DURING TUESDAY MORNING. SHOWERS...WITH PERHAPS A RUMBLE OF THUNDER...WILL END WITH FRONTAL PASSAGE. SKIES WILL BECOME MOSTLY CLEAR IN THE WAKE OF THE FRONT. THE PRESSURE GRADIENT WILL TIGHTEN AND WITH DAYTIME MIXING WILL RESULT IN GUSTY NORTHWEST WINDS. HIGHS WILL BE COOLER THAN MONDAYS READINGS DUE TO CAA...BUT THERE SHOULD BE SOME DIURNAL RISE FROM MORNING READINGS. HIGHS WILL RANGE FROM THE UPPER 50S NW TO THE UPPER 60S SE. FOR TUESDAY NIGHT...MID LVL TROUGH WILL DIG INTO THE EASTERN GREAT LAKES AND NEW ENGLAND WHILE SURFACE HIGH PRESSURE BUILDS INTO THE WESTERN GREAT LAKES AND OHIO VALLEY FROM THE NORTHWEST. SKIES WILL BE MOSTLY CLEAR...EXCEPT IN THE FAR NORTHEAST WHERE CAA STRATOCUMULUS/LAKE EFFECT CLOUDS MAY RESULT IN PARTLY CLOUDY CONDITIONS. A MUCH DRIER AND COLDER AIRMASS WILL SETTLE INTO THE REGION. AS SUCH...TEMPERATURES WILL DROP INTO THE 30S. THE WIND SHOULD STAY UP ENOUGH TUESDAY NIGHT TO PREVENT FROST FORMATION. HOWEVER...TEMPERATURES ACROSS OUR NW ZONES WILL APPROACH THE FREEZING MARK. WILL MENTION THIS POTENTIAL IN THE HWO SHOULD LATER FORECASTS BECOME SLIGHTLY COLDER WHICH MAY RESULT IN THE NEED FOR FREEZE HEADLINES. AS OF TODAY...WE HAVE STARTED THE FROST/FREEZE PROGRAM FOR THE REMAINDER OF THE NORTHERN CWFA WHICH INCLUDES THE DAYTON AND COLUMBUS METROS. ON WEDNESDAY...HIGH PRESSURE WILL SETTLE INTO OUR AREA. DESPITE MOSTLY SUNNY SKIES...COLD TEMPERATURES ALOFT WILL KEEP HIGH TEMPERATURES ON THE COOL SIDE. HAVE USED 925 MB TEMPERATURES AS A PROXY FOR FORECASTING HIGHS. THIS METHOD YIELDS VALUES COOLER THAN MOST MODEL MOS GUIDANCE. HAVE HIGHS RANGING FROM THE UPPER 50S NORTH TO THE LOWER 60S SOUTH. THE HIGH WILL SHIFT EAST OF THE REGION WEDNESDAY NIGHT AS A MID LEVEL RIDGE BUILDS TO OUR WEST. RETURN FLOW/WAA ALOFT IN ASSOCIATION WITH THE RIDGE WILL ALLOW MID AND HIGH LEVEL CLOUDS TO SPILL INTO THE AREA FROM THE NW. MODELS CONTINUE TO HINT A THE POSSIBILITY OF SOME LIGHT SHOWERS DEVELOPING IN THE WAA PATTERN...BUT THE MAJORITY SOLUTION KEEPS THIS LOW THREAT TO OUR NW...SO HAVE MAINTAINED A DRY FORECAST FOR NOW. LOWS WILL BE SLIGHTLY WARMER DUE TO SOME CLOUD COVER. && .LONG TERM /THURSDAY THROUGH MONDAY/... AN ELEVATED WARM FRONT WILL BE MOVING NORTH OF THE REGION EARLY THURSDAY MORNING...PERHAPS CAPABLE OF PRODUCING A SPRINKLE OR LIGHT SHOWER ACROSS THE REGION. AFTER THE MORNING HAS PASSED...THE ILN CWA WILL BE FIRMLY IN THE WARM SECTOR...AHEAD OF AN APPROACHING COLD FRONT. THE FRONT IS ATTACHED TO A SURFACE LOW THAT WILL LUMBER EASTWARD ACROSS THE GREAT LAKES. OVERALL MODEL TIMING WITH THIS FRONT IS FAIRLY STRONG...WITH A SLIGHT DECREASE IN SPEED AS THE ONLY MAJOR CHANGE FROM THE PREVIOUS FORECAST. THE NEW POPS GO AS HIGH AS 60-70 PERCENT FOR THE ENTIRE CWA. INSTABILITY IS STILL FORECAST TO BE WEAK...SO ONLY A SLIGHT CHANCE OF THUNDER HAS BEEN USED FOR THE FORECAST GRIDS. LATER ON FRIDAY MORNING...THE FRONT WILL CLEAR THE REGION QUICKLY. UNDER WESTERLY FLOW...DRIER AIR WILL MOVE INTO THE AREA. WITH MOISTURE LACKING...AND CLEAR SKIES...THE WSW FLOW WILL KEEP THE BIGGEST DROPS IN TEMPERATURE UNTIL OVERNIGHT. A SECOND FRONT WILL UNDULATE SOUTHWARD THROUGH THE GREAT LAKES...SWITCHING WINDS STRONGER TO THE NORTH. COLD ADVECTION IS FORECAST TO BEGIN. ALONG WITH THIS FRONT...A SLIGHT CHANCE OF PRECIPITATION HAS BEEN ADDED TO THE NORTHERN HALF OF THE FORECAST AREA FOR FRIDAY NIGHT INTO SATURDAY MORNING. COLDER AIR WILL MOVE INTO THE AREA ON THE NORTHERLY FLOW...BUT THE POSITION OF THIS BOUNDARY AS IT MOVES SOUTH OF THE CWA WILL HAVE AN IMPACT ON THE WEATHER GOING INTO NEXT WEEK. SIGNIFICANT DIFFERENCES BETWEEN THE OPERATIONAL GFS AND ECMWF RUNS HAVE CONTINUED WITH THE 12Z RUNS...INVOLVING THE FORECAST NEXT WEEK. A LARGE TROUGH OVER THE WESTERN STATES IS FORECAST TO MOVE INTO THE HIGH PLAINS BY MONDAY...WITH A RIDGE EXTENDING SOUTHEAST-TO-NORTHWEST FROM THE SOUTHEASTERN STATES THROUGH THE MISSISSIPPI VALLEY. ANOTHER AREA OF LOW PRESSURE IS FORECAST TO EXIST NEAR NEW ENGLAND. THE STRENGTH OF THESE SYSTEMS WILL HELP DETERMINE THE OVERALL FLOW OVER THE OHIO VALLEY...AND WHETHER OR NOT THE LEFTOVER BOUNDARY ACTIVATES THROUGH THE REGION OR FURTHER SOUTH. THERE ARE NO CLEAR ANSWERS...WITH DIFFERENT STRENGTHS BETWEEN THE UPPER FEATURES FROM MODEL TO MODEL. THE ECMWF IS THE MOST SUPPRESSED WITH THE WESTERN TROUGH...WITH A WEAKER RIDGE THROUGH THE OHIO VALLEY...AND THUS A MUCH WETTER PATTERN. ALTHOUGH THE ECMWF HAS A STRONG LOW OVER NEW ENGLAND...AS THE OPERATIONAL GFS ALSO DEPICTS...THE GFS ENSEMBLE MEAN IS MUCH WEAKER OVER THE NORTHEASTERN STATES. FINALLY...THE CANADIAN MODEL SOLUTION LOOKS VERY SIMILAR TO THE GFS...WITH STRONGER RIDGING AND A SURFACE HIGH BUILDING INTO THE OHIO VALLEY...KEEPING THE REGION UNDER A COLDER AND DRIER AIR MASS. WHILE TEMPERATURES SEEM LIKELY TO BE COOLER THAN NORMAL NEXT WEEK...THE PRECIPITATION FORECAST REMAINS VERY UNCERTAIN. SOME 20-30 PERCENT POPS WERE INTRODUCED WITH A FOCUS ON THE SOUTHERN CWA...FOR THE SECOND HALF OF SUNDAY INTO MONDAY. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/...
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CONDITIONS BEGINNING THE PERIOD VFR WITH SPOTTY SHOWERS. EXPECT THAT TO CONTINUE THROUGH MUCH OF THE NIGHT. THERE IS THE POTENTIAL FOR CEILINGS TO DROP TO MVFR JUST AHEAD OF A COLD FRONT THAT WILL MOVE THROUGH AROUND OR SLIGHTLY AFTER 12Z. FOR SIMPLICITY HAVE INDICATED PREVAILING MVFR CEILINGS BUT BASED ON UPSTREAM CONDITIONS THE MVFR CONDITIONS MAY ONLY BE TEMPORARY. WINDS WILL SHIFT TO NORTHWEST AND SKIES WILL CLEAR BEHIND THE FRONT ALTHOUGH A FEW STRATOCUMULUS COULD PERSIST THROUGH THE DAY. WINDS WILL GUST UP TO 25 KT UNTIL AROUND 00Z. WINDS GRADUALLY DIMINISH LATE IN THE TAF PERIOD UNDER CLEAR SKIES. OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED.
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&& .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HICKMAN NEAR TERM...SITES SHORT TERM...HICKMAN LONG TERM...HATZOS AVIATION...

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