Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 012047 AFDILN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 447 PM EDT WED OCT 1 2014 .SYNOPSIS... HIGH PRESSURE WILL MOVE OFF TO THE EAST TONIGHT AND THURSDAY. SOUTHERLY FLOW DEVELOPING BETWEEN THE DEPARTING HIGH AND LOW PRESSURE OVER THE CENTRAL PLAINS WILL RESULT IN A WARM THURSDAY. THE DEEPENING LOW PRESSURE AND ITS ASSOCIATED COLD FRONT WILL PUSH ACROSS THE GREAT LAKES AND OHIO VALLEY THURSDAY NIGHT THROUGH FRIDAY NIGHT. THIS SYSTEM WILL BRING THE THREAT FOR SHOWERS AND EMBEDDED THUNDERSTORMS DURING THE PERIOD. MUCH COLDER AIR WILL FOLLOW THE FRONT FOR THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... SURFACE HIGH PRESSURE WILL CONTINUE TO EXTEND FROM THE NEW ENGLAND REGION SOUTHWEST INTO THE OHIO VALLEY AREA OVERNIGHT. MEANWHILE...A MID LVL S/WV RIDGE WILL MOVE EAST ACROSS THE REGION. WITH THE SURFACE HIGH IN PLACE...WINDS WILL BE LIGHT TO CALM ACROSS OUR EAST AND SOUTH WITH SOME GRADIENT EXPECTED FOR THE WEST. SOME HIGHER LEVEL CLOUDS WILL TRY TO ENCROACH THE WESTERN ZONES LATE TONIGHT. AS A RESULT...BELIEVE SOME PATCHY FOG WILL DEVELOP OVER THE EASTERN/SOUTHERN ZONES AS THIS AREA WILL HAVE THE MOST EFFICIENT RADIATIONAL COOLING. LOWS WILL RANGE FROM THE MID 40S IN THE COOLER LOCATIONS OF EAST CENTRAL OHIO TO THE LOWER/MID 50S ELSEWHERE. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... HAVE USED A COMBINATION OF CONVECTION ALLOWING MODELS AND THE GFS/ECMWF FOR THURSDAY INTO THURSDAY NIGHT. MID LEVEL S/WV RIDGE WILL MOVE EAST ON THURSDAY. SURFACE RIDGING WILL MOVE EAST AS WELL. MODELS SUGGEST THAT DISTURBED ENERGY WITHIN THE BACK SIDE FLOW OF THE MID LEVEL RIDGE WILL KEEP PCPN THREAT TO OUR WEST/NORTHWEST ON THURSDAY. AS A RESULT...WE SHOULD JUST SEE SOME INCREASE IN CLOUDS FROM THE UPSTREAM SYSTEM. MEANWHILE...LOW PRESSURE WILL BE DEVELOPING ACROSS THE CENTRAL PLAINS. THE FLOW BETWEEN THE DEPARTING HIGH AND THE LOW WILL ALLOW FOR AN INCREASING SOUTHERLY FLOW. ENOUGH FILTERED SUNSHINE WITH LOW LEVEL WAA SHOULD RESULT IN HIGHS RANGING FROM THE LOWER TO MID 80S. THESE TEMPERATURES ARE SOME 10 DEGREES ABOVE NORMAL FOR EARLY OCTOBER. FOR THURSDAY NIGHT...S/WV ENERGY OVER THE CENTRAL PLAINS WILL BE EJECTED QUICKLY NE INTO THE WESTERN GREAT LAKES AS A LARGE SCALE MID LEVEL TROUGH DIGS SOUTHEAST INTO THE NRN PLAINS. AT THE SAME TIME...LOW PRESSURE WILL DEEPEN AS IT MOVES NORTH/NORTHEAST TO THE WESTERN GREAT LAKES. THE COMBINATION OF AN INCREASING LOW LEVEL MOIST ASCENT WITH A LOW LEVEL JET AND THE APPROACHING S/WV WILL ALLOW FOR SHOWERS TO INCREASE FROM WEST TO EAST OVERNIGHT. IT APPEARS THAT THERE WILL BE ENOUGH INSTABILITY FOR A FEW RUMBLES OF THUNDER...BUT THIS IS EXPECTED TO BE OF THE ELEVATED VARIETY. ON FRIDAY...GFS/ECMWF ARE FAIRLY SIMILAR WITH THE TIMING OF SYNOPTIC SCALE SYSTEMS. A SECOND WAVE OF PCPN IS EXPECTED FRIDAY AFTERNOON AS A COLD FRONT PUSHES EAST THROUGH THE AREA WHILE LOW PRESSURE CONTINUES NORTHWARD INTO SOUTHERN CANADA. A VERY MOIST AIRMASS WILL BE IN PLACE WITH PWATS APPROACHING 200 PERCENT OF NORMAL. GIVEN MODERATE BULK SHEAR...THE PROSPECTS OF MLCAPES AROUND 500 J/KG AHEAD OF THE FRONT...LOW LEVEL JET BETWEEN 40 AND 50 KNOTS...LOW LCLS...MID LEVEL JET BETWEEN 50 AND 60 KNOTS...THERE IS SOME CONCERN THAT SOME OF THE CONVECTION ALONG THE FRONT MAY RESULT IN A FEW STRONG...PERHAPS SEVERE STORMS. THE PRIMARY THREAT WOULD BE DAMAGING WINDS. HOWEVER...THIS IS THE TYPE OF SETUP THAT COULD RESULT IN A LOW THREAT OF SPIN UP TORNADOES IF THE CONDITIONS ARE RIGHT. AS A RESULT...WILL MENTION THE THREAT FOR STRONG TO SEVERE STORMS IN THE HWO...WITH DAMAGING WIND BEING THE MAIN THREAT. WILL LEAVE OUT THE THREAT OF TORNADOES FOR NOW UNTIL AND IF IT BECOMES CLEARER THAT THIS MAY BE SOMETHING OF CONCERN. THIS SYSTEM WILL BE THE FIRST SYSTEM TO BRING A DECENT RAINFALL TO MUCH OF THE AREA IN THE LAST TWO WEEKS. SO...ALTHOUGH PWATS WILL BE APPROACHING 200 PERCENT OF NORMAL...AND SOME MODERATE TO LOCALLY HEAVY RAIN WILL BE POSSIBLE...THE DRY ANTECEDENT CONDITIONS AND THE FAST MOVEMENT OF THE CONVECTION SHOULD KEEP THE THREAT FLOOD SUBDUED. FOR FRIDAY NIGHT...THE COLD FRONT WILL MOVE EAST AS A LARGE SCALE MID LEVEL TROUGH DIGS INTO THE GREAT LAKES AND OHIO VALLEY. PCPN SHOULD TAPER OFF THROUGH THE EVENING. THERE WILL BE DECENT COLD AIR ADVECTION IN THE WAKE OF THE FRONT. AS FOR TEMPERATURES...MILD READINGS CAN BE EXPECTED THURSDAY NIGHT. CLOUDS AND PCPN WILL HOLD VALUES IN THE UPPER 60S TO THE LOWER 70S ON FRIDAY. THE CAA FRIDAY NIGHT WILL ALLOW TEMPERATURES TO BOTTOM OUT IN THE LOWER TO MID 40S. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... A SIGNIFICANT CHANGE IN AIRMASS WILL BE ONGOING ON SATURDAY MORNING...AS A PUSH OF COLD AIR MOVES OVER THE OHIO VALLEY. THE BASE OF A 500MB TROUGH WILL BE THROUGH THE AREA...BUT THE COLD AIR ALOFT WILL HELP LEAD TO SIGNIFICANT ENHANCEMENTS IN RH OVER THE GREAT LAKES. AS SOME OF THIS MAKES ITS WAY INTO THE NORTHERN OHIO VALLEY...PRECIPITATION IS EXPECTED FOR THE NORTHERN SECTIONS OF THE ILN CWA ON SATURDAY. CURRENT TEMPERATURE FORECASTS SUGGEST THAT THIS ACTIVITY WILL REMAIN LIQUID...THOUGH TEMPERATURES IN THE NORTH MAY START THE DAY NEAR 40 DEGREES. AFTER THE TROUGH AXIS PASSES THROUGH THE OHIO VALLEY...THE REGION WILL ENTER A REGIME OF DRY NORTHWESTERLY FLOW. AT THE SURFACE...HIGH PRESSURE OVER THE SOUTHEASTERN STATES WILL ALLOW FOR A SLIGHT SOUTHERLY COMPONENT TO THE WINDS. THIS WILL LEAD TO GRADUALLY WARMING CONDITIONS AFTER SATURDAY...WHICH LOOKS TO BE THE COLDEST OF THE EXTENDED FORECAST PERIOD. BEYOND SUNDAY...WHICH APPEARS LIKELY TO BE DRY...CONFIDENCE DECREASES IN THE TIMING OF SHORTWAVE FEATURES THROUGH THE FAST NORTHWEST FLOW. GFSE PLOTS SHOW A WIDE ARRAY OF SPREAD IN TROUGH PLACEMENT AND AMPLITUDE...AND AGREEMENT BETWEEN THE GFS/ECMWF IS ONLY DECENT AT BEST. MONDAY INTO MONDAY NIGHT APPEAR TO HAVE A HIGHER CHANCE THAN OTHER TIME PERIODS FOR PRECIPITATION...AND THIS HAS BEEN REFINED IN THE FORECAST GRIDS...EXTENDING SLIGHTLY INTO TUESDAY. && .AVIATION /20Z WEDNESDAY THROUGH MONDAY/... MORNING STRATUS CONTINUES TO ERODE AND SHOULD BE GONE BY 22Z. SFC HIGH PRESSURE AND H5 RIDGING SHOULD PROVIDE MOSTLY CLEAR SKIES FOR TONIGHT. OVERALL THE SFC FLOW TONIGHT IS FROM THE SE. THIS IS FAVORABLE FOR LIFR FOG CONDITIONS AT KLUK DUE TO RIVER VALLEY FOG. ALSO BUT IFR FOG AT KILN DUE TO ITS PROPENSITY FOR RADIATIONAL FOG IN THESE LIGHT WIND/CLEAR SKIES SITUATIONS. BY 12Z THURSDAY THE FLOW BEGINS TO PICK UP AS UPPER LEVEL ENERGY WORKS UP THE OHIO RIVER. MID CLOUDS SHOULD BE ON THE INCREASE AND SFC WINDS WILL PICK UP QUICKLY ENDING ANY FOG. CIGS SHOULD REMAIN VFR THRU 00Z FRIDAY AND DONT EXPECT ANY PCPN. OUTLOOK...THUNDERSTORMS POSSIBLE LATE THURSDAY NIGHT INTO FRIDAY. MVFR CIGS POSSIBLE FRIDAY NIGHT INTO SATURDAY...THEN AGAIN MONDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HICKMAN NEAR TERM...HICKMAN SHORT TERM...HICKMAN LONG TERM...HATZOS AVIATION...SITES

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