000 FXUS61 KCLE 062359 AFDCLE AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CLEVELAND OH 759 PM EDT SAT SEP 6 2008 .SYNOPSIS... WEAK HIGH PRESSURE WILL BUILD IN THIS EVENING BEHIND A COLD FRONT NOW TO OUR EAST. A DISTURBANCE ALOFT HOWEVER WILL MOVE INTO THE OHIO VALLEY FROM THE CENTRAL PLAINS OVERNIGHT. THIS UPPER TROUGH WILL CONTINUE TO MOVE THOUGH THE AREA ON SUNDAY. SUNDAY NIGHT AND MONDAY ANOTHER AREA OF HIGH PRESSURE WILL BUILD IN FROM THE CENTRAL PLAINS. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... MAIN CONCERN FOR THE EVENING WILL BE THE CLOUDS ACROSS THE EAST THIRD OF THE AREA. THE REMAINDER OF THE CLOUD COVER IS CONVECTIVE IN NATURE AND SHOULD DISSIPATE RATHER QUICKLY THIS EVENING. THE EAST THIRD WILL TAKE A COUPLE MORE HOURS TO CLEAR BUT STILL EXPECT THIS TO OCCUR DURING THE EVENING. OVERNIGHT EXPECT CLOUDS TO INCREASE FROM THE WEST AFTER MIDNIGHT WITH APPROACHING DISTURBANCE. MODELS A BIT FASTER WITH THE MOISTURE VS YDAYS RUNS SO HAVE INTRODUCED A SMALL CHANCE FOR RAIN IN THE FAR NORTHWEST LATE. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY NIGHT/... HAVE FOLLOWED THE NAM FORECAST TRENDS THROUGH THE SHORT TERM PERIOD ALTHOUGH THE NAM AND GFS ARE NOT TOO FAR OFF INITIALLY. FOR SUNDAY BOTH MODELS SHOW THE UPPER DISTURBANCE MOVING EAST ACROSS THE AREA. WITH MINOR DIFFERENCES IN TIMING AND INTENSITY. ENOUGH AGREEMENT HOWEVER FOR AT LEAST MID/HIGH CHC POPS ACROSS THE REGION. DRIER AIR WILL MOVE IN BEHIND THE SYSTEM SUNDAY NIGHT. SO WILL GO WITH BECOMING PARTLY CLOUDY IN ZONES. MONDAY AFTERNOON BROUGHT IN A SLIGHT CHANCE IN THE GRAPHICS HAVING BACKED OFF FROM CHC IN EARLIER FORECASTS. NAM SHOWS UPPER TROUGH DIGGING INTO THE CENTRAL PLAINS WITH SURFACE CYCLOGENESIS TAKING PLACE IN MISSOURI. AHEAD OF THE DEVELOPING LOW WARM FRONTOGENESIS WILL OCCUR FROM THE LOW NORTHEAST ACROSS SRN LWR MI AND NRN OH. MONDAY EVENING INTO TUESDAY THERMAL GRADIENT WILL CONTINUE TO INCREASE WITH AN 850MB FLOW APPROACHING 50 KTS ACROSS THE AREA BY TUESDAY MORNING. MOST OF THE ISENTROPIC LIFT APPEARS TO BE NORTH OF THE AREA. MONDAY EVENING HAVE INCREASED POPS TO CHC IN THE NORTHWEST AND THEN AFTER MIDNIGHT INCREASED FURTHER TO HIGH CHC. TUESDAY SHOULD BE THE BEST CHANCE FOR SHOWERS AND THUNDERSTORMS AS THE ASSOCIATED COLD FRONT SWINGS QUICKLY THROUGH THE AREA. STARTED POPS OUT WITH CHC CATEGORY EAST AND LIKELY WEST. FOR THE AFTERNOON APPEARS ENOUGH DRY AIR MOVES INTO THE WEST TO REMOVE POPS. IN THE EAST WILL BOOST TO LIKELY. TUESDAY NIGHT DRY AIR CONTINUES ACROSS THE REMAINDER OF THE AREA SO CLEARING AND COOLER LOOKS LIKE A GOOD TREND. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... MODELS ARE IN AGREEMENT IN STARTING OUT THE PERIOD ON WEDNESDAY WITH HIGH PRESSURE OVER THE AREA WHICH SHIFTS INTO NEW ENGLAND BY LATE THURSDAY TO ALLOW A RETURN FLOW TO DEVELOP AND BRING INCREASING MOISTURE AND TEMPERATURES. THE NEXT WEATHER MAKER WILL BE A COLD FRONT THAT IS EXPECTED TO MOVE ACROSS THE AREA ABOUT FRIDAY WITH THE MODELS STILL REMAINING FAIRLY CONSISTENT WITH THIS FEATURE SO REASONABLY CONFIDENT WITH THE FRONT ALTHOUGH THE TIMING COULD BE OFF A LITTLE. FRONT SHOWN TO SWEEP THROUGH WITH MORE HIGH PRESSURE PUSHING IN FOR DRY WEATHER BY SATURDAY. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... WEAK HIGH PRESSURE BUILDING IN HAS CLEARED SKIES OVER MOST OF THE FORECAST AREA THIS EVENING. SKIES WILL BE MOSTLY CLEAR AND VISIBILITIES WILL BE GOOD TO START WITH. EASTERN AREAS ESPECIALLY INLAND AREAS WILL LIKE SEE MVFR OR IFR WEATHER IN FOG LATE TONIGHT AND EARLY SUNDAY MORNING. A TROF ALOFT OVER THE CENTRAL PLAINS WILL MOVE ENE THROUGH THE AREA ON SUNDAY. SOME LIGHT SHOWERS ARE POSSIBLE AND COULD BRING SOME LOCAL MVFR CONDITION BUT BELIEVE VFR WEATHER SHOULD PREVAIL EVEN IN MOST OF THE SHOWERS. THE TREAT OF SHOWERS SHOULD END BY EARLY AFTERNOON FAR WEST AND BY END TAF PERIOD IN EAST. OUTLOOK...VFR WEATHER SHOULD PREVAIL FROM SUNDAY NIGHT UNTIL UNTIL A LOW AND COLD FRONT MOVE THROUGH THE AREA MONDAY NIGHT INTO TUESDAY WHEN MORE AREAS OF MVFR ARE EXPECTED IN SHOWERS AND POSSIBLE THUNDERSTORMS. HIGH PRESSURE TO PROVIDE WIDESPREAD VFR WED THEN A CHANCE FOR MORE AREAS OF MVFR SHOULD RETURN LATE THU INTO THU NIGHT AS SCT SHRA AND TSRA AGAIN DEVELOP. && .MARINE... HIGH PRESSURE BUILDING OVER LAKE ERIE FROM THE WEST SHOULD BE PUTTING AND END TO THE SMALL CRAFT CONDITIONS OVER THE EASTERN HALF AROUND FORECAST ISSUE TIME. CONTINUED DIMINISHING WINDS TONIGHT AS THE HIGH MOVES EAST ACROSS OHIO AND OFF THE EAST COAST THROUGH MONDAY. SOME QUESTION MONDAY NIGHT AS A S TO SW FLOW SHOULD INCREASE BUT THE EXACT POSITION OF A WAVE OF LOW PRESSURE MOVING ALONG THE FRONT WILL HAVE A BIG DIFFERENCE ON THE POTENTIAL FOR WHEN SMALL CRAFT WINDS MAY DEVELOP...IF NOT AHEAD OF THE COLD FRONT THEN ALMOST CERTAINLY IN THE COLDER AIR IN THE WAKE OF THE FRONT. HIGH PRESSURE AND LIGHT FLOW RETURN FOR WED THEN AN INCREASING S FLOW EXPECTED ON THU. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...TK NEAR TERM...TK SHORT TERM...TK LONG TERM...ADAMS AVIATION...RANDEL MARINE...ADAMS