Area Forecast Discussion
Issued by NWS Wilmington, OH

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KILN 291054 AFDILN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 654 AM EDT WED OCT 29 2014 .SYNOPSIS... HIGH PRESSURE WILL BEGIN TO MOVE INTO THE OHIO VALLEY TODAY. A TROUGH OF LOW PRESSURE AND A COLD FRONT WILL MOVE INTO THE REGION FRIDAY...BRINGING CHANCES FOR PRECIPITATION THROUGH SATURDAY MORNING...AND MUCH COOLER CONDITIONS FOR THE WEEKEND. A WARMING TREND WILL BEGIN EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A FEW REMAINING SHOWERS ARE EXITING THE SOUTHEASTERN CORNER OF THE FORECAST AREA...LEAVING DRY CONDITIONS EXPECTED FOR THE REST OF THE DAY. A WEDGE OF CLEARING IS EXPECTED TO BUILD INTO THE FORECAST AREA TODAY...BEHIND THE STREAM OF HIGH CLOUDS...AND AHEAD OF ANY LOW CLOUDS THAT WILL EVENTUALLY MOVE SOUTH FROM THE GREAT LAKES. IN ADDITION...CUMULUS DEVELOPMENT APPEARS LIKELY...WITH BOUNDARY LAYER MIXING THROUGH AROUND 875MB-850MB. AS THIS MIXING OCCURS...OCCASIONAL WIND GUSTS OF 15-20 KNOTS WILL BE POSSIBLE. WEAK COLD ADVECTION WILL CONTINUE THROUGH THE DAY ON WNW FLOW...BUT WITH ENOUGH SUN TO ALLOW FOR ABOUT A TEN-DEGREE RISE IN TEMPERATURES FROM MORNING LOWS. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/... THE FIRST CONCERN FOR THE SHORT TERM FORECAST IS THE POTENTIAL FOR FROST EARLY THURSDAY MORNING. RAW MODEL TEMPERATURES SEEM UNANIMOUS IN ALLOWING FOR TEMPERATURES IN THE LOWER TO MID 30S ACROSS THE VAST MAJORITY OF THE FORECAST AREA. HOWEVER...THERE REMAIN SOME SIGNIFICANT CONCERNS REGARDING THE WIND AND CLOUD FORECASTS. WINDS ARE NOT EXPECTED TO BECOME CALM (OR NEAR-CALM) UNTIL CLOSE TO SUNRISE...THOUGH THEY WILL BECOME LIGHT IN THE EASTERN HALF OF THE FORECAST AREA. CLOUDS ARE EXPECTED TO BE FAIRLY PERSISTENT FOR THE NORTHERN HALF OF THE FORECAST AREA...WITH RATHER LOW CONFIDENCE IN THE SPECIFIC CLOUD FORECAST ELSEWHERE. COMBINING ALL THESE FACTORS TOGETHER...CONDITIONS MAY COME TOGETHER TO BE THE MOST FAVORABLE FOR FROST IN THE EAST-CENTRAL PART OF THE FORECAST AREA (WHITEWATER VALLEY). PATCHY FROST WILL BE MAINTAINED IN THE GRIDS FOR A FAIRLY LARGE AREA...WITH HWO MENTIONS CONTINUING. HOWEVER...OWING TO UNCERTAINTY AND COLLABORATION WITH SURROUNDING FORECAST OFFICES...HEADLINE ISSUANCE WAS DEFERRED. THE CENTER OF AN AREA OF SURFACE HIGH PRESSURE WILL BE OVER THE REGION ON THURSDAY...IN A BRIEF PERIOD OF TRANSITION BETWEEN DISTURBANCES...WITH LIGHT WINDS AND SLIGHTLY CLEARER CONDITIONS. A BRIEF PERIOD OF SOUTHWESTERLY FLOW ON THURSDAY NIGHT WILL ALLOW TEMPERATURES TO STAY IN THE LOWER 40S HEADED INTO FRIDAY. FROM FRIDAY INTO SATURDAY...A COMPLEX WEATHER SYSTEM WILL AFFECT THE OHIO VALLEY. A SHARP MID-LEVEL TROUGH IS EXPECTED TO DEVELOP INTO A COMPACT CLOSED LOW AS IT MOVES SSE OUT OF THE CANADIAN PLAINS...CROSSING THE WESTERN GREAT LAKES ON FRIDAY...AND REACHING THE SOUTHEASTERN STATES ON SATURDAY MORNING. THE STRENGTH OF THIS SYSTEM (AS NOTED BY HEIGHT ANOMALIES) IS VERY MUCH OUT OF THE ORDINARY...THOUGH OVERALL...THE IMPACTS FOR THE ILN FORECAST AREA WILL BE MOST NOTABLE IN TERMS OF TEMPERATURES (AND NOT DUE TO ANY SIGNIFICANT HAZARDOUS WEATHER). AT THE SURFACE...A COLD FRONT IS FORECAST TO MOVE SOUTHEAST THROUGH THE FORECAST AREA ON FRIDAY. THIS REQUIRED A NON-DIURNAL TEMPERATURE CURVE...WITH A GRADIENT IN MAX TEMPERATURES FROM NORTHWEST TO SOUTHEAST. THE FRONT IS NOT EXPECTED TO BE A SIGNIFICANT FOCUS FOR PRECIPITATION ON ITS OWN...BUT A LARGE AREA FAVORABLE FOR ASCENT WILL BE LOCATED AHEAD (EAST) OF THE MID-LEVEL LOW...ESPECIALLY AS A REGION OF UPPER DIVERGENCE MOVES THROUGH ON FRIDAY EVENING. HIGH-CHANCE TO LIKELY POPS HAVE BEEN INCLUDED FOR THE ENTIRE FORECAST AREA...AND THOUGH THE PLACEMENT OF THE LOW IS A LITTLE DIFFERENT FROM MODEL TO MODEL...THE CONSENSUS SUGGESTS THAT THE EASTERN HALF OF THE FORECAST AREA WILL BE THE MOST LIKELY TO RECEIVE A MORE PROLONGED PERIOD OF PRECIPITATION. NORTHERLY WINDS BEHIND THE FRONT ARE EXPECTED TO BE RATHER GUSTY...AND WIND GUSTS FRIDAY NIGHT HAVE BEEN INCREASED INTO THE MIDDLE TO UPPER 20S (WITH THE HIGHEST VALUES IN THE NORTHERN HALF OF THE CWA). AS TEMPERATURES CONTINUE TO COOL BEHIND THE SURFACE FRONT ON FRIDAY NIGHT...MODEL SOUNDINGS SUGGEST THAT SUB-FREEZING AIR WILL EVENTUALLY WORK ITS WAY CLOSE ENOUGH TO THE SURFACE TO ALLOW FOR WET SNOW TO MIX WITH RAIN. HOWEVER...THIS CONTINUED EVOLUTION IN THE BOUNDARY LAYER THERMAL ENVIRONMENT WILL BE ACCOMPANIED BY DRYING CONDITIONS AND THE LOSS OF ASCENT...WITH ALMOST ALL APPRECIABLE QPF OUTPUT SHUNTING EAST BEFORE CONDITIONS BECOME COLD ENOUGH FOR SNOW. CHANGES TO THE WEATHER GRIDS WERE GENERALLY JUST AN EVOLUTION OF THE PREVIOUS FORECAST...WITH A TRANSITION TO A CHANCE OF A RAIN/SNOW MIX LATE IN THE EVENT DURING THE MORNING HOURS ON SATURDAY. ACCUMULATING SNOW APPEARS VERY UNLIKELY. A SLIGHT CHANGE TO THE TIMING OF THE SYSTEM HAS ALSO RESULTED IN THE EXPECTATION FOR CLOUDS REMAINING IN PLACE THROUGH SATURDAY MORNING...ESPECIALLY FOR THE EASTERN HALF OF THE FORECAST AREA. THIS RESULTED IN A SLIGHT UPWARD ADJUSTMENT IN MIN TEMPS FRIDAY NIGHT / SATURDAY MORNING...MAKING FROST/FREEZE CONDITIONS A LITTLE MORE UNLIKELY. IN THE FACE OF CONTINUED COLD ADVECTION...GRADUALLY CLEARING CONDITIONS ON SATURDAY WILL NOT BE ENOUGH TO ALLOW FOR MUCH OF AN INCREASE IN TEMPERATURES. HIGHS ARE FORECAST TO BE IN THE LOWER 40S...15-20 DEGREES BELOW NORMAL. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... AN EXTENSIVE AREA OF HIGH PRESSURE WILL FOLLOW THE UPPER LOW. THIS WILL PROVIDE A PERIOD OF DRY WEATHER SUNDAY AND MONDAY. FOR TUESDAY...A FRONTAL BOUNDARY DEVELOPING ALONG A SOUTHWEST UPPER FLOW MAY TAP A STREAM OF PACIFIC MOISTURE TO PRODUCE RAIN SHOWERS. COOL TEMPERATURES ARE IN STORE FOR THE PERIOD...ESPECIALLY AT THE START. HIGHS ON FRIDAY IN THE UPPER 40S ARE EXPECTED TO OCCUR AROUND NOON WITH FALLING READINGS IN THE AFTERNOON DUE TO STRONG COLD ADVECTION ON A NORTHERLY FLOW. HIGHS IN THE LOWER 40S SATURDAY WILL BE AROUND 15 DEGREES BELOW NORMAL. LOWS IN THE 20S SATURDAY AND SUNDAY WILL PUT AN END TO THE GROWING SEASON. HIGHS ARE FORECAST TO REBOUND BACK INTO THE 50S BY TUESDAY AS WARM ADVECTION CAUSES THE ATMOSPHERE TO RECOVER TOWARD NORMAL. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
FOR TODAY...A MID LVL TROUGH WILL MOVE EAST/SOUTHEAST INTO THE REGION. A GRADUAL INCREASE IN LOW LEVEL MOISTURE...ALONG WITH CAA...WILL RESULT IN AN INCREASE OF CUMULUS/STRATOCUMULUS CLOUDS DURING THE AFTERNOON AND EVENING. BEST COVERAGE WILL BE ACROSS THE NORTHERN TAF SITES. DAYTIME MIXING WILL BRING SUSTAINED WEST WINDS BETWEEN 10 AND 15 KNOTS WITH GUSTS UP TO 25 KNOTS IN SOME SPOTS. FOR TONIGHT...MID LEVEL TROUGH WILL MOVE OFF TO THE EAST AS SURFACE HIGH PRESSURE BUILDS INTO AND EVENTUALLY SETTLES OVER THE OHIO VALLEY BY THURSDAY MORNING. STRATOCUMULUS SHOULD SLOWLY ERODE OVERNIGHT. WINDS ARE FORECAST TO DIMINISH AND VEER TO THE NORTH. OUTLOOK...MVFR/IFR CEILINGS AND VISIBILITIES POSSIBLE FRIDAY INTO SATURDAY MORNING...THEN MVFR CEILINGS POSSIBLY LINGERING INTO THE REMAINDER OF SATURDAY.
-- End Changed Discussion --
&& .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM...HATZOS SHORT TERM...HATZOS LONG TERM...CONIGLIO AVIATION...HICKMAN

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.