Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 202348 AFDILN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 748 PM EDT SAT SEP 20 2014 .SYNOPSIS... A STRONG COLD FRONT WILL SHIFT THROUGH THE GREAT LAKES TONIGHT AND SUNDAY WITH THE THREAT FOR SHOWERS AND THUNDERSTORMS. A MILD NIGHT IS IN STORE AHEAD OF THE FRONT TONIGHT...WITH LOWS IN THE 60S. COOLER AIR WILL DROP IN QUICKLY BEHIND THE FRONT SUNDAY AFTERNOON AND NIGHT...LEADING TO SEVERAL NIGHTS WITH LOWS IN THE 40S...WITH PERHAPS SOME UPPER 30S IN OUTLYING AREAS. MUCH OF THE WORK WEEK WILL FEATURE STRONG HIGH PRESSURE...WHICH WILL BRING MILD DAYS...COOL NIGHTS...AND LOW HUMIDITY. PLENTY OF SUN IS EXPECTED THROUGH THE WEEK. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... UPDATE...SPED UP ARRIVAL OF RAIN CHANCES BY AN HOUR OR TWO BASED ON TIME TRENDS FROM RADAR ON NOW WELL-DEVELOPED LINE OF CONVECTION FROM NERN IND BACK TO WCNTL IND. MOST CONCENTRATED N-S PORTION OF LINE WITH HISTORY OF WIND DAMAGE WILL PASS NORTH OF OUR AREA THROUGH EARLY EVENING. REST OF LINE SEEMS TO BE STRUGGLING TO BE SEVERE...AND WE/RE WATCHING PORTION OF THE LINE FROM LOGANSPORT BACK TO IL BORDER AS THE PORTION THAT WILL AFFECT US. GUST FRONT NOW KICKING SWRD FROM SEGMENT OF LINE FROM COLUMBIA CITY BACK TO LOGANSPORT SO THIS PORTION OF LINE LIKELY TO WEAKEN. MESOA OVER IND/OH SHOWS INSTBY DECREASING WITH EWRD EXTENT INTO ILN CWA AND WITH SUNSET APPROACHING STILL THINK OVERALL SEVERE THREAT IS MARGINAL. DID UPDATE HWO TO GIVE HEADS UP TO WCNTL OHIO/ECNTL IND COUNTIES THAT A GUSTY/WEAKENING LINE OF STORMS IS LIKELY 00Z-02Z. REF MCD#1741 THAT A NEW WATCH /IF ISSUED/ MAY GRAB A COUPLE OF OUR FAR NWRN COUNTIES. ALSO PULLED RAIN CHANCES IN NRN KY AS CUMULUS/PVS SHRA DOWN THERE HAVE LARGELY DISSIPATED. PREVIOUS DISCUSSION -> SEVERAL FOCI FOR PRECIPITATION NOW THROUGH SUNRISE ON SUNDAY MORNING. FIRST...IS IN A RELATIVELY NARROW AXIS OF HIGHER THETA-E THAT RUNS NORTHEAST ALONG THE OHIO RIVER INTO THE CVG AREA THIS AFTERNOON. BOUNDARY LAYER DWPTS HAVE WITHSTOOD MIXING TO REMAIN IN THE MID 60S YIELDING SOME MARGINAL MLCAPE FROM 200-500 J/KG. CONFLUENT FLOW/VERY WEAK CONVERGENCE HAS LED TO THIS EXTENSION OF BUOYANCY AND SOME ISOLD SHRA HAVE DEVELOPED IN THIS AXIS AND WILL CONTINUE TO DO SO THROUGH ABT 7-8 PM TIED STRONGLY TO THE BOUNDARY LAYER FLOW/INSTBY. HAVE PLACED A SMALL RAIN CHANCE IN PARTS OF OUR NRN KY COUNTIES FOR THIS EVENING TO ACCOUNT FOR THIS THREAT. LARGER CONCERN IS STRONG COLD FRONT WHICH IS SHIFTING THROUGH WI/IA/NRN IL ATTM ATTENDANT TO A COUPLE OF HEIGHT FALL CENTERS...ONE IN WI THIS AFTN AND ANOTHER VERY COMPACT ONE IN ERN ND. LOW LEVEL FORCING IS STRONG WITH THE FRONT AND ASSOCIATED PRE- FRONTAL TROUGH...AND DEEP LAYER FLOW IS INCREASING AS THE THROUGH AMPLIFIES WITH TIME TONIGHT. CONVECTION HAS RECENTLY ERUPTED AS OF 19Z JUST SOUTH OF CHICAGO AND SPC WATCH #504 ACCOMPANIES THIS INCREASE IN CONVECTION OFF TO OUR NW. ACCORDING TO 20.12Z AWR-WRF...20.09Z SREF...AND MULTIPLE WELL-AGREED UPON HRRR RUNS...A RATHER ROBUST LINE OF STORMS WILL DEVELOP ALONG/AHEAD OF THE FRONT OVER THE NEXT FEW HOURS AND PUSH EAST/NORTHEAST. ORIENTATION/MAGNITUDE /30+KTS BY TONIGHT/ OF 0-3KM SHEAR VECTOR IS FAVORABLE FOR SOME DURATION/ORGANIZATION TO LINE SEGMENTS WHICH CAN ORIENT IN MORE N-S FASHION OR SOME VARIATION OF THAT. NOT SURPRISINGLY...HRRR RUNS HAVE DEMONSTRATED SPORADIC SWATHS OF DAMAGING WIND GUSTS > 50KTS ACROSS NRN IND POTENTIALLY INVOLVING NWRN/WCNTL OH LATER THIS EVE /AFTER 10 PM OR SO/. REALLY LIKE THE 5% WIND CONTOUR INTO WCNTL OHIO BASED ON THE HRRR/ARW WRF SOLUTIONS SHOWING A WEAKENING ORGANIZED LINE COMING INTO OUR AREA AROUND 10 PM...PERHAPS WITH SOME 40-50 MPH WINDS. THIS FITS CURRENT MESOA WHICH HAS MINIMUM OF INSTBY IN WRN OH DUE TO MIXED DWPTS IN THE 50S...SO LINE SHOULD WEAKEN CONSIDERABLY AS IT CROSSES INTO OHIO...DESPITE BRINGING A MODEST INCREASE IN MOISTURE VIA ADVECTION. STRUGGLED A LOT WITH RAIN CHANCES...FEEL CONFIDENT ENOUGH FOR LIKELY RAIN CHANCES WITH DYING LINE INTO ABOUT THE NWRN 1/2 OF OUR FORECAST AREA...BUT ALL CAMS/PARAMETRIZED DATA SHOWING ACTIVITY BECOMING MORE SCT WITH TIME AS NIGHT WEARS ON. SO RAIN CHANCES OVERNIGHT RANGE FROM A LOW CONFIDENCE 20% IN FAR SOUTH/EAST UP TO A 70% CHANCE OR SO IN WCNTL OH. ALL WILL DEPEND HOW QUICKLY THE INCOMING LINE WEAKENS. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... FIRST HEIGHT FALL CENTER MENTIONED ABOVE PULLS EAST OF THE AREA SUNDAY MORNING TAKING PRIMARY CONVERGENCE/PREFRONTAL TROUGH WITH IT THROUGH THE MORNING. RESIDUAL SHOWERS/STORMS TO CROSS THE AREA IN THE MORNING AND THEN SCT STORMS WILL BEGIN TO BUBBLE ALONG THIS BOUNDARY LATE MORNING/EARLY AFTERNOON AND LIKELY IN OUR FAR SOUTH/EAST OR JUST OUT OF OUR AREA. RATHER IMPRESSIVE/NARROW DRY SLOT SHOULD WRAP IN LATE MORNING/EARLY AFTERNOON WITH SOME SUNSHINE BEFORE STRONG CAA SETS IN DURING THE AFTERNOON WITH THE PASSAGE OF SECONDARY FRONT. WITH SHALLOW INSTBY DEVELOPING...COULD SEE SOME SCT SHRA DEVELOP WITH THIS FEATURE WHICH WAS ALREADY WELL HANDLED BY PVS FORECASTER. THIS MOST LIKELY ACROSS OUR NORTH CLOSER TO STRONG/COMPACT SHORTWAVE DIGGING ACROSS NRN OH. DON/T EXPECT MUCH IF ANY THUNDER AFTER ABOUT 18Z...AS INSTBY BECOMES TOO SHALLOW FOR CHARGE SEPARATION. WILL DEFINITELY A BE A CHANGEABLE /AUTUMN-LIKE DAY DESPITE MAX TEMPS IN THE 70S. WINDS WILL BECOME BREEZY/GUSTY IN THE AFTN AS THE COLD ADVECTION ARRIVES AND CHANGEABLE SKY WITH THE DRY SLOT TO LOWER CLOUDS ALONG/BEHIND THE SECONDARY SURFACE FRONT. AS THIS ACTION ALL CLEARS THE CWA SUNDAY NIGHT AND STRONG HIGH PRESSURE BUILDS IN...A VERY CHILLY NIGHT IN STORE WITH LOWS WELL INTO THE 40S IN OUR INDIANA/WRN OHIO COUNTIES AS 925MB TEMPS DROP TO +5C IN THIS AREA BY SUNRISE ON MONDAY. SHOULD SEE A SLOW DECREASE IN LOW CLOUDS THROUGH THE NIGHT AND LESSENING WINDS AS WELL...GIVEN THE DEGREE OF COLD AIR INBOUND...AM A LITTLE WORRIED I AM CLEARING THE SKIES A LITTLE TOO QUICKLY AND STRATOCUMULUS MAY BE MORE WIDESPREAD. MONDAY BRINGS 1024MB SURFACE HIGH PRESSURE SPRAWLING INTO THE GREAT LAKES AND CENTERED NEAR CHICAGO BY MONDAY EVENING. SHOULD BE PLENTY OF SUNSHINE WITH DEWPTS IN THE 40S. CONTINUED WEAK CAA SHOULD KEEP 925MB TEMPS IN THE +8 TO +10C RANGE WHICH PER CLIMO STUDY SUGGESTS MAX TEMPS IN THE LOW TO MID 60S MOST AREAS...DESPITE PLENTY OF SUN. MONDAY NIGHT WILL BE COLDEST OF THE WEEK AND WOULD NOT BE SURPRISED TO SEE COLD PRONE/OUTLYING SITES TOUCH THE MID TO UPPER 30S AGAIN LIKE DELAWARE/MARYSVILLE ETC DID LAST WEEK. MAY EVEN BE A TOUCH COLDER THIS TIME AROUND. LOW TEMPS THIS NIGHT MAY STILL BE A DEGREE OR TWO TOO WARM IN GOING FORECAST...ESPECIALLY WITH SURFACE HIGH MOVING RIGHT OVERHEAD AT 12Z AND THE VERY DRY PROFILE /PWATS RUNNING 40% OF NORMAL/. AN IDEAL RADIATIONAL COOLING SIGNAL BEING SEEN IN THE DATA. && .LONG TERM /TUESDAY THROUGH SATURDAY/... MID/UPPER LEVEL RIDGE WILL REMAIN IN PLACE ACROSS THE REGION THROUGH THE END OF THE WEEK. THIS WILL RESULT IN DRY CONDITIONS AND FAIRLY SEASONABLE TEMPERATURES THROUGH THE LONG TERM PERIOD. AS THE AIRMASS SLOWLY MODIFIES...HIGH TEMPERATURES WILL GRADUALLY WARM EACH DAY...FROM THE LOW TO MID 70S MID WEEK INTO THE UPPER 70S TO AROUND 80 DEGREES BY THE WEEKEND. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/...
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LINE OF STORMS DEVELOPED TO OUR WEST ACROSS INDIANA IN MODERATE INSTBY AHD OF SFC COLD FRONT AND WAS BEGINNING TO PUSH INTO NW OHIO. INSTBY SHARPLY DROPS OFF INTO MARGINAL CATEGORY ACROSS OHIO. THIS LINE WAS SHOWING A WEAKENING TREND AND EXPECTED TO CONTINUE TO WEAKEN AS IT MOVES INTO LESS FAVORABLE THERMAL ENVIRONMENT. HAVE TIMED A PERIOD OF VCSH TO ACCOUNT FOR REMNANTS OF THIS CONVECTION AT ALL TAF SITES TONIGHT. EXPECT A PERIOD OF MVFR CIGS LATE TONIGHT PRIOR TO SFC COLD FRONT SWEEPING THRU SUNDAY MORNING. EXPECT SOME IMPROVEMENT TO CIGS FOR A PERIOD SUNDAY AFTN WHEN VFR CONDITIONS ARE EXPECTED. LOW LEVEL MOISTURE ASSOCIATED WITH UPR LEVEL TROF LATE AFTN INTO SUNDAY EVENING. EXPECT THESE CIGS TO BE VFR BETWEEN 4000 AND 5000 FEET BUT A PERIOD OF MVFR CIGS CAN NOT BE RULED OUT. SW WINDS WILL CONTINUE AROUND 10 KTS TONIGHT AND THEN SHIFT WEST WITH FROPA ON SUNDAY AND THEN BECOME NW SUNDAY AFTN. WINDS WILL GUST AS HIGH AS 27 KTS SUNDAY IN WAKE OF THE FRONT OUTLOOK...MVFR CEILINGS POSSIBLE SUNDAY NIGHT.
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&& .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...BINAU NEAR TERM...BINAU SHORT TERM...BINAU LONG TERM...JGL AVIATION...AR

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