Area Forecast Discussion
Issued by NWS Wilmington, OH

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
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 242349 AFDILN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 749 PM EDT SUN APR 24 2016 .SYNOPSIS... HIGH PRESSURE WILL MOVE EAST OF THE REGION TODAY...WITH SOUTHERLY FLOW BRINGING A WARMING TREND THROUGH TOMORROW. A COLD FRONT WILL MOVE INTO THE REGION FROM THE NORTHWEST LATE ON MONDAY...PROVIDING CHANCES FOR SHOWERS AND STORMS OVERNIGHT AND INTO TUESDAY. THIS FRONT WILL REMAIN IN PLACE OVER THE AREA THROUGH THE MIDDLE OF THE WEEK...PROVIDING SLIGHTLY COOLER CONDITIONS AND CONTINUED CHANCES FOR RAIN. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... SURFACE HIGH PRESSURE IS NOW CENTERED WELL EAST OF THE OHIO VALLEY...AS STACKED LOW PRESSURE BEGINS TO MOVE EAST ACROSS SOUTH DAKOTA. WITH A WIDE GEOGRAPHIC SPREAD BETWEEN SYSTEMS...THE PRESSURE GRADIENT OVER THE REGION TODAY IS FAIRLY WEAK. NONETHELESS...SOME SLIGHT WARM ADVECTION HAS BEGUN...AND A DAY OF FULL SUN HAS ALLOWED TEMPERATURES TO CLIMB INTO THE UPPER 60S TO MID 70S. WITH VERY LITTLE MOISTURE ADVECTING IN...DRY LOW AND MID LEVELS WILL REMAIN IN PLACE THROUGH THE NEAR TERM...WITH DEWPOINTS JUST STARTING TO RISE BEFORE SUNRISE ON MONDAY MORNING. MIN TEMPS ARE EXPECTED TO RANGE FROM THE MID 50S IN THE SOUTHWEST CWA TO AROUND 50 IN THE EASTERN CWA...POSSIBLY WITH SOME UPPER 40S IN OUTLYING AREAS NORTH AND EAST OF COLUMBUS. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... AFTER A QUIET WEEKEND...A MORE ACTIVE PATTERN IS SETTING UP FOR THE NEW WEEK. THE UPPER LOW OVER SOUTH DAKOTA WILL QUICKLY WEAKEN AND FLATTEN INTO A BARELY-DETECTABLE WAVE...WHILE THE ASSOCIATED SURFACE LOW IS FORECAST TO WEAKEN AS WELL...THOUGH A SURFACE COLD FRONT WILL GRADUALLY PROGRESS TOWARD THE SOUTHERN GREAT LAKES. THIS FRONT SHOULD REMAIN WELL UPSTREAM ON MONDAY...WITH THE ENTIRE OHIO VALLEY REMAINING IN THE WARM SECTOR. WITH A MID-LEVEL RIDGE AXIS MOVING FURTHER TO THE EAST...SOUTHWESTERLY FLOW WILL BECOME MORE WELL-ALIGNED THROUGH THE DEPTH OF THE ATMOSPHERE...CREATING A BETTER PATTERN FOR THETA-E ADVECTION THAN TODAY. THIS WILL CONTRIBUTE TO A SLIGHT RISE IN TEMPERATURES (UPPER 70S TO LOWER 80S ON MONDAY) IN ADDITION TO A LARGER RISE IN BOUNDARY LAYER DEWPOINTS (MID 40S ON SUNDAY TURNING INTO MID 50S ON MONDAY). WITH ESSENTIALLY NO FORCING AND THE PRESENCE OF A WEAK MID-LEVEL CAP...CONVECTION IS NOT EXPECTED TO DEVELOP DEEP WITHIN THE WARM SECTOR. UPSTREAM CONVECTION IS EXPECTED TO DEVELOP LATE MONDAY AFTERNOON AND INTO THE EVENING...AND THESE STORMS (WHICH WILL LIKELY BE IN A WEAKENING STATE OVERNIGHT) WILL MOVE SOUTHEAST THROUGH THE ILN FORECAST AREA. THIS IS WHERE THE FIRST INCREASE IN POPS HAS BEEN FOCUSED...RUNNING FROM AROUND 03Z IN THE NORTHWESTERN CWA TO 15Z IN THE SOUTHEASTERN CWA. CURRENT MODELS DO NOT YET SUGGEST THAT THIS WOULD BE A GUARANTEED CHANCE OF RAIN ACROSS THE AREA...ESPECIALLY FURTHER SOUTH IN THE FORECAST AREA BY EARLY TUESDAY MORNING. THE DECAYING INSTABILITY WITH THE LOSS OF DIURNAL HEATING WILL LIMIT ANY CHANCES FOR STRONG STORMS...FAVORING A LOW-END WIND POTENTIAL DURING THE LATE EVENING IN THE NORTHERN CWA...LIKELY TO BE SUB-SEVERE. AS THE FRONT MOVES INTO THE AREA ON TUESDAY...A SETUP FOR CONVERGENCE (LOW-LEVEL FORCING) WILL BECOME MORE WELL DEFINED. THE FRONT IS NOT EXPECTED TO CLEAR THROUGH THE ENTIRE CWA...BUT WILL LIKELY STALL ABOUT HALFWAY THROUGH...PIVOTING FROM WSW-TO-ENE TO MORE OF A WNW-TO-ENE ORIENTATION. THIS WILL DEFINITELY INCREASE THE TEMPERATURE GRADIENT ACROSS THE FORECAST AREA FROM NORTH TO SOUTH...WITH AN 8-10 DEGREE SPREAD EXPECTED. ANY LEFTOVER MORNING PRECIPITATION SHOULD WEAKEN AND MOVE EAST OF THE CWA ON TUESDAY MORNING...WITH SOME DECREASE IN CLOUDS ALSO EXPECTED GOING INTO THE DAY. WITH HEATING AND INCREASING DEWPOINTS EXPECTED SOUTH OF THE FRONT...ALIGNED WITH COOLING TEMPERATURES ALOFT...INSTABILITY IS EXPECTED TO GROW SIGNIFICANTLY. WHILE MODELS STILL DIFFER IN THE AMOUNTS OF EXPECTED INSTABILITY (AND THE CLOUD SITUATION DURING THE DAY WILL ALSO HAVE AN IMPACT)...SREF PROBABILITIES SUGGEST MLCAPE VALUES COULD BE AS HIGH AS 1200-1800 J/KG IN THE SOUTHERN SECTION OF THE FORECAST AREA. STORM INITIATION IS EXPECTED TO OCCUR DURING THE AFTERNOON...BUT THE EXACT TIMING AND PLACEMENT IS A LITTLE BIT UNCERTAIN...AS THE TIMING OF ANY WEAK SHORTWAVES OR SURFACE BOUNDARIES MAY HAVE MORE OF AN INFLUENCE THAN ANY LARGE SCALE FEATURES (THE SURFACE FRONT WILL BE MOSTLY STALLED...ACTING AS A FOCUS FOR CONVECTION...BUT NOT NECESSARILY ACTING AS A FEATURE TO BE USED FOR TIMING PURPOSES). A LIMITING FACTOR FOR THE SEVERE POTENTIAL IS THE WIND SHEAR...WHICH IS FORECAST TO BE RELATIVELY WEAK THROUGH A DEEP LAYER. THIS FORECAST AGREES WITH THE GENERAL IDEA FROM THE CURRENT HAZARDOUS WEATHER OUTLOOK...AND NO CHANGES APPEAR TO BE NECESSARY. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... FRONTAL BOUNDARY NEAR OUR SOUTHERN/WESTERN CWFA BORDER WILL REMAIN QUASI-STATIONARY ON WEDNESDAY. SOME LIFT WILL OCCUR UP AND OVER THE BOUNDARY THROUGH THE DAY WHICH WILL KEEP A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE FORECAST. FOR WEDNESDAY NIGHT...A LEAD S/WV IS STILL FORECAST TO MOVE WEST TO EAST ACROSS THE REGION. THIS WILL HELP IMPINGE A LOW LEVEL JET ALONG THE FRONTAL BOUNDARY AS IT TRIES TO LIFT A LITTLE TO THE NORTH. THIS DYNAMIC SETUP SHOULD SPREAD SHOWERS AND EMBEDDED THUNDERSTORMS FROM WEST TO EAST OVERNIGHT. FOR THURSDAY INTO THURSDAY NIGHT...SOME DISCREPANCY BEGINS TO OCCURS AMONGST THE OPERATIONAL MODELS. GFS IS THE QUICKEST WITH ANOTHER S/WV MOVING ACROSS THE SOUTHERN GREAT LAKES COMPARED TO THE ECMWF. A WEAK SFC LOW IS FORECAST TO ACCOMPANY THIS FEATURE ALONG OUR FRONTAL BOUNDARY...ALLOWING THE FRONT TO MOVE SOUTHEAST AS A COLD FRONT THURSDAY NIGHT. HAVE SIDED WITH THE FASTER GFS WHICH KEEPS SOME CONTINUITY WITH THE PREVIOUS FORECAST. A CHANCE OF SHOWERS AND THUNDERSTORMS WILL CONTINUE ON THURSDAY. PCPN CHANCES WILL DWINDLE THURSDAY NIGHT FROM NORTHWEST TO SOUTHEAST. WEAK RIDGING WILL RETURN FOR FRIDAY INTO FRIDAY NIGHT ALONG WITH DRY AND SEASONAL TEMPERATURES. 12Z GUIDANCE IS STILL SHOWING TIMING DISCREPANCIES WITH THE APPROACH OF THE NEXT SYSTEM OVER THE WEEKEND. HAVE TAKEN A SUPERBLEND OF MODELS TO ACCOUNT FOR THE TIMING DIFFERENCES WHICH FAVORS THE HIGHEST CHANCE FOR SHOWERS/THUNDERSTORMS TO OCCUR ON SUNDAY. NEAR TO SLIGHTLY ABOVE NORMAL TEMPERATURES ARE EXPECTED. && .AVIATION /00Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
AN AREA OF THIN BROKEN CI HAS WORKED INTO THE TAFS FOR THE START OF THE FCST PERIOD. ADDITIONAL CI IS EXPECTED OVERNIGHT...WITH IT GOING SCATTERED AT TIMES. AFT 06Z...THE SFC FLOW BEGINS TO TIGHTEN UP AND LOW LEVEL MOISTURE BEGINS TO INCREASE. MODELS ARE TRYING TO BRING IN A CIG AROUND 5K BY 09Z IN THE SOUTH AND LIFT IT NORTH. BY MID MORNING...THIS MOISTURE MIXES OUT...BUT STILL EXPECT SOME VFR CU THROUGHOUT THE DAY. THE GFS...12Z AND 18Z RUNS...IS THE ONLY MODEL TRYING TO PRINT OUT QPF TOMORROW. WILL LEAVE THE TAFS DRY FOR NOW. WINDS PICK UP TOMORROW IN THE TIGHTENING PRESSURE GRADIENT. THE TAFS SHOULD SEE SUSTAINED WINDS INTO THE MID TEENS WITH GUSTS TO AROUND 20 KTS. OUTLOOK...MVFR CIGS AND VSBYS WITH SOME THUNDERSTORMS POSSIBLE LATE MONDAY NIGHT INTO TUESDAY...THEN AGAIN WEDNESDAY INTO THURSDAY.
-- End Changed Discussion --
&& .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM...HATZOS SHORT TERM...HATZOS LONG TERM...HICKMAN AVIATION...SITES

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