Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 211053 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 653 AM EDT Fri Oct 21 2016 .SYNOPSIS... Low pressure will continue to move northeast today slowing pulling the backedge of the rain eastward with it. A much colder airmass will filter into the region today and Saturday, before warmer air works back into the region for Sunday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... The center of low pressure and a cdfnt are located over West Virginia early this morning. This has allowed winds to turn to the north and temperatures to fall into upper 40s and 50s. However, sharp H5 trof will swing thru the fa this morning. This is combining with a deformation axis to produce a secondary band of rain across IN into wrn OH. It will take a good part of the morning for deformation zone to work thru the fa, and to bring an end to the chance of rain. Some rain could linger in the extreme eastern counties into early afternoon. Strong pressure gradient on the backside of the low will keep winds gusty, especially this morning. Gusts 20-30 mph will be possible. CAA will persist through the day with 850 mb temperatures dropping down below 0C by late afternoon. This will counteract the drier air trying to build in this afternoon, to linger the clouds today. With the cloud cover, temperatures will be limited to the lower to mid 50s, with a few spots in the Cincy Tri-State making the upper 50s. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... By 00Z the H5 trof axis will be into the Appalachians, leaving the fa in nw flow both at the sfc and aloft. Feel that there will be enuf cold air aloft to linger the clouds overnight. The clouds will help keep temperatures up a little, but they still be a little below normal falling in the upper 30s and lower 40s. Surface high pressure will begin to build up into the Tennessee Valley. While this keep dry conditions on Saturday, lingering cold air aloft will allow for clouds to redevelop especially during the afternoon. This will keep temperatures in the 50s, ranging from the lower 50s in the east to the mid 50s in the west. Saturday night will see H8 temperatures warming, but think that the atmosphere will decouple enough for a small diurnal drop in temperatures. Lows Saturday night will drop back into the lower to mid 40s. On Sunday, southwest winds at the sfc will bring warm air back into the region. A few high clouds could affect the region in fast flow aloft, but there will be plenty of sunshine and temperatures should make the mid to upper 60s for highs. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... Sunday night into Monday morning a shortwave will push southeast down mid-level ridging and around the upper level low. The GFS is slightly more progressive and weaker with the shortwave compared to the ECMWF. Both 20.12z model runs bring the shortwave slightly further west than yesterday and therefore try to bring the heart of the colder air slightly further west as well. The ECMWF and the GFS push the front through the area by Monday evening. The frontal passage also appears to be a dry frontal passage as PWATs remain around 0.60". Behind the front highs will cool down back to normal as the heart of the cold air still misses the area (850 mb temperatures around 4 degrees C). Tuesday the upper level trough will finally head east of the area taking the cooler air with it. Wednesday into Thursday a shortwave will eject out of the midwest and approach the area. This means clouds will begin to increase on Wednesday and into Thursday. Have also introduced a chance of rain into the forecast Thursday as the low approaches. PWATs on the GFS rise to above 1.00" with limited instability. Upper level forcing looks good though as the ILN forecast area is in the diffluent side of the trough axis and widespread PV moves over the area. For now have just edged the chance of precipitation up as model consistency remains low at this time. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... A weak low pressure east of the terminals will continue to lift northeast away from the area. Pcpn associated with the deformation axis is now beginning to pivot east across the region. This area has filled in quite nicely over the past several hours with -SHRA/-DZ with pockets of heavier pcpn. Still do think that back edge of pcpn will work east of KDAY/KCVG/KLUK around/shortly after 14z. Anticipate drying trend towards latter part of the afternoon for eastern sites of KCMH and KLCK. In the meantime, CIGS will continue to hover around 1k ft and periodically bounce between low MVFR and IFR. IFR CIGs have been more prevalent in pockets of heavier pcpn, so have accounted for this in the TEMPO groups. Do anticipate that as axis of -SHRA works east, that CIGs will go strictly MVFR, with the potential for VFR late afternoon for western sites of KCVG, KDAY, and KLUK. In the wake of the low, a fairly pronounced pressure gradient has settled over the area which will lead to northwesterly winds of 12 to 15 kts with gusts up to 25 kts through the afternoon. The gradient will relax from west to east late this afternoon, allowing for a weakening trend by evening. Winds will be 5 to 10 kts tonight. Main concern tonight will be potential for a stream of low level moisture off Lake Michigan to filter into western parts of the area. Models have been fairly consistent showing this axis developing, which may lead to MVFR CIGs once again for western sites past 06z Saturday. Although there remains some uncertainty on the exact extent and location of the stream of low level moisture, the eastern sites will likely remain VFR through the overnight period. OUTLOOK...No significant weather expected. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...JGL/Sites NEAR TERM...Sites SHORT TERM...Sites LONG TERM...Haines AVIATION...KC is the U.S. government's official web portal to all federal, state and local government web resources and services.