Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 280010 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 710 PM EST Sun Nov 27 2016 .SYNOPSIS... High pressure and a dry airmass will move east tonight. Moisture will increase Monday as low pressure travels to Minnesota, with widespread showers expected Monday night. Drier weather will follow for Tuesday in the relatively dry southerly flow behind the low. More showers will be likely Wednesday when a large swath of moisture and forcing is forecast to move up along the Appalachian Mountains. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... Surface high pressure centered near the Carolina coast will keep dry weather over the ILN area tonight. Mid and high clouds will increase ahead of vigorous low pressure advancing toward Minnesota. This will allow overnight lows in the mid 30s northeast to around 40 southwest, a bit above normal. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... Moisture will be increasing well ahead of the low on Monday. Clouds will thicken and lower, and showers may develop by afternoon, mainly over western locations closer to the low. For Monday night, the initial low center in the vicinity of western Minnesota will fill in, while another low develops and moves to Lake Michigan. The ILN area will be under a very strong low level jet ahead of this system, resulting in a concentrated plume of moisture being advected from the southwest. Showers will develop in convergence and lift under the jet. Kept categorical pops as measurable rain is nearly certain. Rainfall averaging 1 inch is indicated by model QPF, breaking the dry spell. Decided to keep thunder out of the forecast in a regime containing limited instability. Breezy conditions are expected, with gusts around 30 mph common, and higher gusts likely with heavy showers. Tuesday will feature drier conditions as the band of showers moves quickly east. Showers may develop again Tuesday night in a swath of moisture and forcing arriving on a southwest flow aloft. Temperatures will exhibit a warming trend in the persistent southerly flow. Highs are forecast to be in the 50s Monday, rising to the 60s most locations on Tuesday. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... On Wednesday morning, a stacked area of low pressure will be located over Minnesota, with a shortwave trough developing to its south from Iowa to Oklahoma. The overall pattern ahead of this feature will be amplifying, with deep-layer southwesterly flow (and a very fast upper jet) running from Texas to the eastern Great Lakes. The Ohio Valley will be in this regime, which will see an increase in forcing through Tuesday night into Wednesday, especially just to the southeast of the forecast area. Several elements are coming together, with upper support from the jet, mid-level frontogenesis, and some convergence along an approaching surface cold front. Models have converged on the faster ECMWF solution, bringing the highest chances for precipitation through the region in the 12Z-21Z time frame. With good agreement on timing and a slight northwestward shift in position from previous runs, PoPs have been increased -- with room to increase even further in future forecasts. Hazardous weather is unlikely, but there is some potential for a decent amount of rainfall in the southern and southeastern sections of the CWA, which could be beneficial. Though Wednesday will be relatively mild, with temperatures above normal, cooler conditions are expected once the cold front passes through late in the day. However, with boundary layer flow only turning to the WSW behind the front, cold advection is not expected to be particularly strong. This will set up several days with temperatures slightly below normal, but not significantly so. As the large upper low elongates from west-to-east while moving across Canada, cool temperatures aloft will help lead to mostly cloudy conditions through the end of the week. As the coolest 850mb/700mb air rotates across the southern Great Lakes on Friday evening / Saturday morning, a few light rain or snow showers could be possible near or north of Interstate 70. Generally zonal flow is expected heading into the weekend, with a slight upward adjustment in temperatures, but uncertainty in the forecast increases significantly beyond Saturday. && .AVIATION /00Z MONDAY THROUGH FRIDAY/...
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High pressure will move off the Carolina coast by Monday morning as deepening low pressure pivots northward across the central and northern Plains. For our region, considerable mid and high level clouds will increase/thicken overnight. A deeper plume of moisture along with warm/moist ascent will bring some showers near the western terminals toward 12Z. On Monday, as low pressure occludes over the northern Plains, embedded energy rotating around the mid level circulation will eject from the southern plains to the lower Ohio Valley through the day. As this occurs, deeper moisture and eventually widespread showers will gradually pivot east/northeast into our area. The surface pressure gradient will tighten through the period along with a developing 70-80 knot 850 mb low level jet. Conditions will lower to MVFR from west to east as showers become moderate to locally heavy and saturation allows ceilings to drop. The increasing low level jet will bring winds at 2000 feet into the 55 to 65 knot range toward 00Z, so non convective LLWS was added to the western terminals for this likely occurrence. Surface winds will increase into the 15 to 20 knot range with gusts at least in the lower 30 knots possible by evening. For Monday night, embedded energy will perturb another area of low pressure to our northwest while an occluded front moves through our the region. Widespread showers will occur ahead of the front along with continuing MVFR conditions. Precipitation is expected to quickly come to an end from west to east late Monday night into Tuesday morning along with decreasing winds and improving conditions. OUTLOOK...MVFR ceilings and visibilities with showers expected Monday night into early Tuesday morning, along with the potential for wind gusts in the lower 30 knots. MVFR ceilings and visibilities possible Wednesday into Wednesday night.
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&& .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Coniglio NEAR TERM...Coniglio/Hickman SHORT TERM...Coniglio LONG TERM...Hatzos AVIATION...Hickman

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