Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 110543 AFDILN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 143 AM EDT FRI APR 11 2014 .SYNOPSIS... A COLD FRONT WILL SAG SOUTHEAST INTO THE REGION TONIGHT. THIS FRONT WILL EVENTUALLY SETTLE ALONG AND SOUTH OF THE OHIO RIVER AS A STATIONARY FRONT BY FRIDAY NIGHT. SOUTHERLY FLOW WILL RETURN ON SATURDAY AS THE FRONT MOVES BACK NORTH AS A WARM FRONT. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... ADJUSTED TEMPERATURES AND DEWPOINTS ALONG WITH THE DECREASING WINDS TO HAVE OBSERVED VALUES A LITTLE MORE WEIGHTED IN THE NEXT FEW HOURS. LOWERED THE CHANCE FOR SHOWERS SLIGHTLY IN THE HERE AND NOW GIVEN NW CWA WAS IN THE LIKELY CATEGORY WITHOUT PRECIP YET...THOUGH CLOSE BY. WHILE THE THREAT FOR THUNDERSTORMS IS DECREASING...THE ACTIVITY IS JUST GETTING GOING NOW AND I DID NOT FEEL THAT REMOVING THUNDER FROM A DEVELOPING SYSTEM WAS THE WAY TO HANDLE THE EVENING UPDATE. SCALED BACK THE QPF FROM THE SYSTEM AS THIS APPEARED A BIT OVERDONE. && .SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/... UPR LVL S/WV WILL EXIT TO THE EAST ON FRIDAY ALONG WITH A WEAKENING/SHIFTING LOW LEVEL JET TO THE EAST. POPS WILL REMAIN HIGH ACRS THE SOUTHEAST CWFA EARLY ON...THEN THEY WILL DIMINISH INTO THE AFTERNOON HOURS AS THE FORCING DECREASES AND MOVES AWAY FROM A SLOW-MOVING FRONTAL BOUNDARY. WE SHOULD SEE SOME SUNSHINE ACRS THE NRN ZONES WITH CLOUDS HANGING TOUGH ALONG AND SOUTH OF THE OHIO RIVER. HIGHS WILL RANGE FROM THE LOWER TO MID 60S. FOR FRIDAY NIGHT...FRONTAL BOUNDARY WILL BECOME STATIONARY ALONG AND SOUTH OF THE OHIO RIVER. PRECIPITATION SHOULD COME TO END BY THEN. WITH RECENT RAINFALL...LIGHT WINDS...AND WITH PARTIAL CLEARING...SREF ENSEMBLES INDICATE THE POSSIBILITY OF LOW CLOUDS AND/OR FOG FORMING...ESPECIALLY ACRS THE SRN TWO THIRDS OF THE CWFA. GIVEN THAT FOG IS OFTEN HARD TO PREDICT...ESPECIALLY THIS FAR OUT...HAVE NOT MENTIONED IT YET IN THE FORECAST...BUT WE WILL HAVE TO MONITOR TRENDS TO SEE IF A STRONG SIGNAL EXISTS TOMORROW AT THIS TIME. FOR SATURDAY INTO SATURDAY NIGHT...STALLED OUT FRONTAL BOUNDARY WILL MOVE NORTH AS A WARM FRONT AS UPR LVL FLOW BEGINS TO BUCKLE AND LOW PRESSURE DEVELOPS ACROSS THE WESTERN GREAT LAKES. LOW LEVEL MOISTURE AND INSTABILITY WILL INCREASE ALONG AND BEHIND THE WARM FRONT ON SATURDAY. OTHER THAN THE BOUNDARY ITSELF...THERE SEEMS TO BE A LACK OF GOOD FORCING. THUS...HAVE CONTINUED TO LIMIT POPS TO SLIGHT CHANCE FROM LATE SATURDAY MORNING INTO SATURDAY EVENING AS THE WARM FRONT LIFTS NORTH. INCREASING SOUTHERLY FLOW WILL ALLOW TEMPERATURES TO WARM INTO THE LOWER AND MID 70S ON SATURDAY FOLLOWED BY WARM NIGHTTIME READINGS IN THE 50S SATURDAY NIGHT. && .LONG TERM /SUNDAY THROUGH THURSDAY/... THE FIRST HALF OF THE EXTENDED FORECAST PERIOD WILL BE ACTIVE...GENERALLY FROM THE MIDDLE OF THE COUNTRY TO THE EAST COAST. THE ILN CWA WILL BE IN A WARM ADVECTION PATTERN TO START THINGS OFF ON SUNDAY...WITH ANY CHANCES OF PRECIPITATION ASSOCIATED WITH THE LEADING EDGE OF THE WARM AIR ALOFT MOVING JUST NORTH OF THE AREA. THE MAIN AREA OF PRECIPITATION...ASSOCIATED WITH A SURFACE FRONTAL BOUNDARY THROUGH THE GREAT LAKES...WILL PIVOT AND ACQUIRE MORE OF A NORTH-TO-SOUTH ORIENTATION BY MONDAY MORNING. DISTINCT SHORTWAVES IN THE NORTHERN AND SOUTHERN STREAMS (SLIGHTLY MORE OBVIOUS ON THE 12Z ECMWF COMPARED TO OTHER MODELS) WILL DRIVE TWO MAIN WAVES OF PRECIPITATION OVER THE EASTERN HALF OF THE COUNTRY. THE FIRST WAVE...ALONG AND BEHIND THE COLD FRONT...IS THE ONE THAT IS CERTAIN TO AFFECT THE ILN CWA. LIKELY POPS HAVE BEEN USED FROM 15Z MONDAY MORNING THROUGH 00Z THAT EVENING. AN OPEN SOUTHERLY FEED OF MOISTURE WILL ALLOW FOR A LOW-END THREAT FOR SOME HEAVY RAIN...BUT WITH MODEL INDICATIONS OF THE SURFACE WAVE TIMING ON THE FRONT FAVORING THE ILN AREA TO BE IN A RELATIVE MIN OF QPF AMOUNTS...IT DOES NOT APPEAR TO BE VERY SIGNIFICANT. FURTHERMORE...WHILE WINDS ARE RATHER STRONG THROUGH THE COLUMN JUST AHEAD OF THE FRONT...THEIR UNFAVORABLE ORIENTATION (PARALLEL TO THE FRONT) AND A LACK OF INSTABILITY WILL PRECLUDE A THREAT FOR STRONG STORMS. THUNDER WILL CERTAINLY BE POSSIBLE...THOUGH THE WELL-DEFINED THETA-E BOUNDARY WILL PUT AN END TO THAT THREAT BY AFTERNOON FOR MOST OF THE CWA. A SECOND WAVE OF PRECIPITATION (ASSOCIATED WITH THE SOUTHERN STREAM SHORTWAVE) WILL PRIMARILY AFFECT AREAS SOUTH AND EAST OF THE ILN CWA...BUT THE TREND WITH THE 12Z MODELS HAS BEEN TO HANG THIS OVER THE AREA A LITTLE LONGER INTO TUESDAY. POPS HAVE BEEN ADJUSTED FOR THIS. WITH TEMPERATURES COOLING INTO THE LOWER 30S (AT LEAST FOR THE NORTHERN CWA) ON TUESDAY MORNING...A BRIEF MIXING OF LIGHT RAIN AND SNOW WILL BE POSSIBLE. FOR ABOUT 12 HOURS ON EITHER SIDE OF THE FRONTAL PASSAGE...NON-DIURNAL TEMPERATURES WERE REQUIRED. BASED ON FRONTAL TIMING (NOT UNTIL MONDAY AFTERNOON)...THE EASTERN HALF OF THE CWA WILL BE PSEUDO-DIURNAL. HOWEVER...THE WESTERN HALF WILL BEGIN COOLING OFF (AND FAIRLY QUICKLY) AFTER NOON. COOL AND DRY SURFACE HIGH PRESSURE WILL MOVE INTO THE GREAT LAKES AND NORTHERN OHIO VALLEY ON WEDNESDAY...SHIFTING EAST ON THURSDAY. AT THE SAME TIME...WEAK RIDGING WILL BE MOVING INTO THE EASTERN HALF OF THE COUNTRY. THIS POINTS THE WAY TOWARD A GRADUAL WARMING AND MOISTENING TREND THROUGH THE END OF THE WEEK...BUT DRY CONDITIONS ARE EXPECTED THROUGH FRIDAY. WIND DIRECTIONS AT THE SURFACE WILL NOT REALLY BE FAVORABLE FOR MUCH WARM ADVECTION ON THURSDAY (WITH A SIGNIFICANT EASTERLY COMPONENT)...THOUGH ALOFT...TEMPERATURES AND HIGH CLOUDS WILL BEGIN TO INCREASE. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/...
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A COLD FRONT WILL SLOWLY SAG SOUTHWARD ACROSS THE TERMINALS OVERNIGHT. LIGHT TO MODERATE RAIN WILL PRODUCE MVFR VSBYS AT TIMES THROUGH THE EARLY MORNING. RAIN IS EXPECTED TO EXIT THE AREA SHORTLY AFTER SUNRISE. THERE IS A CHANCE THAT MVFR CIGS MAY DEVELOP AROUND SUNRISE. WAS OPTIMISTIC IN KEEPING THESE CLOUDS SCT RATHER THAN BKN FOR THIS TAF ISSUANCE. SKIES WILL CLEAR FROM NORTHWEST TO SOUTHEAST DURING THE DAYTIME WITH JUST SOME SCT HIGH CLOUDS LINGERING IN THE EVENING. LIGHT STEERING FLOW BEHIND THE FRONT WILL RESULT IN VARIABLE WINDS AT TIMES DURING THE DAY. OUTLOOK...MVFR CIGS AND VSBYS ALONG WITH THUNDERSTORMS ARE POSSIBLE MONDAY.
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&& .FIRE WEATHER... A RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM FOR THE SOUTHEAST PORTION OF THE CWFA DUE TO GUSTY SOUTHERLY WINDS AND LOW RELATIVE HUMIDITIES. WINDS WILL DIMINISH AFTER SUNSET AS DIURNAL MIXING WANES AS THE SURFACE DECOUPLES FROM THE LOWER ATMOSPHERE. THE SURFACED PRESSURE GRADIENT WILL BEGIN TO RELAX AS WELL. RELATIVE HUMIDITIES WILL RECOVER AS TEMPERATURES COOL AND LOW LEVEL MOISTURE ADVECTS IN FROM THE SOUTHWEST. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HICKMAN NEAR TERM...FRANKS SHORT TERM...HICKMAN LONG TERM...HATZOS AVIATION...FRANKS/HATZOS/LATTO FIRE WEATHER...

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