Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 310621 AFDILN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 221 AM EDT MON AUG 31 2015 .SYNOPSIS... A WARM AND HUMID PATTERN IS BECOMING LOCKED IN ACROSS THE OHIO VALLEY THROUGH THE UPCOMING WEEK...WITH LITTLE THREAT FOR MEANINGFUL RAINFALL BEYOND ISOLATED TO SCATTERED SHOWERS AND STORMS FOCUSED IN THE PEAK HEATING OF THE AFTERNOON WANING BY EARLY TO MID EVENING. TEMPERATURES INTO THE MIDDLE AND UPPER 80S ARE EXPECTED INTO NEXT WEEKEND. THE BETTER CHANCES OF ISOLATED TO SCATTERED STORMS APPEAR TO BE FOCUSED ON MONDAY AND TUESDAY ACROSS CENTRAL OHIO...BEFORE THE THREAT APPEARS TO DIMINISH SOMEWHAT TOWARD THE MIDDLE AND END OF THE WORK WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... RADAR TRENDS HAVE BEEN DOWNWARD SINCE ABOUT 630PM...WITH CONVECTION SHUNTING NORTH AND WEAKENING. THE SLOW MOTIONS HAVE MANAGED TO KEEP SOME OF THESE CELLS PRODUCING PERSISTENT HEAVY RAINFALL (PERHAPS AN INCH OR TWO IN ISOLATED SPOTS) BUT THE THREAT FOR ANYTHING MORE SIGNIFICANT APPEARS TO HAVE ENDED FOR THE NIGHT. POPS WILL GRADUALLY TREND DOWNWARD THROUGH AROUND 09Z...WITH DRY CONDITIONS BY MONDAY MORNING. TEMPERATURE AND SATELLITE TRENDS SUGGEST THAT THE SOUTHERN HALF OF THE CWA MAY GET A LITTLE COOLER THAN PREVIOUSLY EXPECTED...SO MIN TEMPS WERE DROPPED BY A DEGREE OR TWO. PREVIOUS DISCUSSION > ISOLATED SHOWERS/STORMS HAVE DEVELOPED AMIDST ROBUST INSTBY /MLCAPE FROM 1500 TO 1750 J/KG OWING TO SFC DEW POINTS IN THE UPPER 60S TO AROUND 70/ AND VERY WEAK SHEAR. KILN VWP AND OBJECTIVE ANALYSIS INDICATES EFFECTIVE SHEAR AROUND 10-15KTS MEANING THESE UPDRAFTS WILL BEHAVE IN VERY PULSEY FASHION THROUGH THE REMAINDER OF THE DAY INTO THE EARLY EVENING. WHILE AN ISOLATED WIND GUST TO 50 MPH IS A POSSIBILITY /GIVEN DCAPE APPROACHING 1000 J/KG/ THIS WOULD ONLY OCCUR WITH THE MOST INTENSE CORES...WHICH WILL BE TOUGH TO COME BY GIVEN THE WEAK FLOW/WEAK LAPSE RATE ENVIRONMENT. EXPECT ACTIVITY TO CONTINUE TO BE LOOSELY FOCUSED DUE TO THE ABSENCE OF SURFACE BOUNDARIES...AND VARIOUS WEAK VORTICITY MAXIMUM WOBBLING THROUGH THE WEAK FLOW UNDERNEATH BROAD LONGWAVE RIDGING. MAIN THREATS OUTSIDE OF A LOCALIZED STRONG WIND GUSTS WILL BE VERY LOCALIZED HEAVY RAIN WITH THE SLOW MOVING STORMS...OR ANY BRIEF CELL MERGERS WHICH PROLONG THE DURATION OF INTENSE RAIN. WITH PWAT ONLY AROUND 1.40" - RAINFALL EFFICIENCY IS NOT OVERLY HIGH AND DRY AIR ENTRAINMENT SHOULD LEAD TO STORM COLLAPSE/COLD POOL PROPAGATION WITH TIME. LOWS TONIGHT IN THE MID 60S AND PERHAPS SOME FOG LATER IN THE NIGHT...LIKELY CONFINED TO THE FOG PRONE RIVER VALLEYS AND LOW LYING AREAS. RAIN CHANCES SLOWLY WANE THROUGH THE EVENING. POTENT UPPER TROUGH SHOWN NICELY IN GOES WATER VAPOR LOOPS EJECTING THROUGH GEORGIA THIS AFTERNOON WILL SHEAR/ACCELERATE NORTHEAST THROUGH THE MID-APPALACHIAN REGION OVERNIGHT AND MAY BRUSH SOUTH-CENTRAL OHIO/NORTHEAST KENTUCKY WITH SOME LIGHT RAIN POTENTIAL LATER TONIGHT - SO LINGERED THE THREATS A LITTLE LATER DOWN THERE. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/... COMPLEX...POSITIVELY TILTED WEAKNESS IN THE MID/UPPER LEVEL HEIGHT FIELD WITHIN A BROAD/STRONG LONGWAVE TROUGH WILL CONTINUE TO PLAGUE THE REGION THROUGH TUESDAY. THERE ARE NUMEROUS SMALL SCALE VORTICITY MAXIMUMS FORMING WITHIN AND RETROGRADING SOUTHWESTWARD WITHIN THIS HEIGHT WEAKNESS...AND DESPITE THE SHEARED/WEAK APPEARANCE OF THESE FEATURES THERE/S ENOUGH FORCING TO KEEP AT LEAST A SMALL /ISOLD/SCT/ THREAT FOR DIURNALLY ENHANCED SHOWERS AND STORMS ACROSS THE OHIO VALLEY BOTH DAYS. THIS WILL BE AUGMENTED BY SEASONALLY WARM/MOIST AIRMASS WITH DEW POINTS IN THE MID/UPPER 60S AND TEMPERATURES IN THE MID/UPPER 80S. WITH SUCH WEAK FLOW...STORMS WILL BE SLOW MOVING AND WON/T MOVE MUCH BEYOND THEIR INITIATION...WHICH ADMITTEDLY COULD BE OVER A LARGE AREA GIVEN A LACK OF BOUNDARIES IN THE LOWEST 3KM OF THE SURFACE. SO WILL CONTINUE TO RUN WITH 20-30% RAIN CHANCES MAINLY NEAR THE MID LEVEL SHEAR ZONE/HEIGHT WEAKNESS WHICH ORIENTS ACROSS WCNTL/CNTL OH PRIMARILY AND INTO ADJACENT AREAS OF SRN OH AND SERN INDIANA. EXPECT MOST AREAS WILL REMAIN DRY...BUT DON/T EXPECT RADAR TO BE ECHO-FREE EITHER AFTERNOON/EARLY EVENING. NO REAL WX HAZARDS WITH THESE STORMS /LOCALIZED WIND GUSTS TO 40 MPH OR SO/ AND ISOLATED HEAVY RAIN TOTALS GIVEN THE SLOW/WAYWARD MOTIONS. EXPECT ACTIVITY TO HAVE A DIURNAL MAX/MINIMUM SO KEPT RAIN CHANCES OUT OF THE FORECAST DURING THE NIGHTTIME HOURS. TEMPERATURES SEEM PRETTY STRAIGHTFORWARD BOTH DAYS...MIDDLE/UPPER 80S BY DAY AND MIDDLE/UPPER 60S BY NIGHT. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... NUMERICAL MODEL SOLUTIONS GENERALLY SIMILAR WITH MAINLY DRY AND WARM WEATHER THROUGH THE LONG TERM FORECAST PERIOD. WEAK MID LEVEL SHORTWAVE TO TOP RIDGE AXIS AND MOVE THRU THE OHIO VALLEY EARLY WEDNESDAY. HAVE INCLUDED SLIGHT CHANCE POPS IN THE EAST EARLY WED AND THEN DRY THE AREA OUT AS THE S/W SHIFTS EAST. WARM TEMPERATURES TO CONTINUE WITH HIGHS ON WED IN THE MID/UPR 80S. MID/UPR LEVEL RIDGE AXIS OVER THE NATIONS MID SECTION BUILDING EAST INTO GREAT LAKES/OHIO VALLEY BY NEXT WEEKEND. THIS RIDGE WILL ACT TO INHIBIT WIDESPREAD THUNDERSTORM ACTIVITY DUE TO A LACK OF ENHANCED FORCING. CAN NOT RULE OUT DIURNALLY DRIVEN ISOLD CONVECTION BUT DUE TO LIMITED COVERAGE AND PROBABILITY...AT THIS TIME HAVE OPTED TO KEEP THE FCST DRY FROM THURSDAY THRU NEXT WEEKEND. ABOVE NORMAL TEMPERATURES TO CONTINUE WITH HIGHS GENERALLY IN THE MID AND UPPER 80S. A FEW SPOTS WILL LIKELY HIT 90 OVER THE SOUTH AND SOUTHEAST. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... STORMS HAVE ENDED THIS OVERNIGHT PERIOD AND SKIES HAVE ALSO SHOWN A MARKED DECREASE IN CLOUD COVER. H5 LOW IS RETROGRADING WEST TOWARDS INDIANAPOLIS TODAY AND WEAK SURFACE HIGH PRESSURE IS ALSO SLOWLY PUSHING NORTHWEST INTO OHIO VALLEY FROM ERN KY. MODELS WERE SHOWING A GOOD BIT LESS QPF IN SHOWER AND THUNDERSTORM ACTIVITY TODAY WHICH SEEMS A FAIR REPRESENTATION GIVEN THAT THE REGION IS WORKED OVER AND A DEFINITIVE MOISTURE MAXIMA ON ANY LEVEL IS NOT BEING SHOWN TODAY. ONE DIFFERENCE HERE IS THAT 4KFT MOISTURE IS A BIT DEEPER OVER KCMH/LCK LATER TODAY. VCSH IN THE 18-0Z TIME FRAME TODAY WAS ALREADY IN FCST AND THIS IS STILL POSSIBLE...THOUGH I WOULD NOT HAVE INTRODUCED IT WITH THE EXPECTATION THAT ANY SHOWERS/THUNDERSTORMS WOULD BE ISOLATED TODAY. WIND FIELDS ARE LIGHT AND WILL BE SOUTH-SOUTHWEST TODAY AND RELAX TO CALM LATER THIS EVENING. THIS WOULD ALSO SUPPORT MVFR VSBYS IN FOG...TRENDING TO A LOWER VSBY REDUCTION TOWARDS MORNING...BEYOND THE 24 HOUR TAF PERIOD AT THIS TIME. OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...BINAU NEAR TERM...BINAU/HATZOS SHORT TERM...BINAU LONG TERM...AR AVIATION...FRANKS

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