Area Forecast Discussion
Issued by NWS Cleveland, OH

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000 FXUS61 KCLE 251354 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 954 AM EDT Tue Sep 25 2018 ...Wet and Potentially Stormy Late Today into Tonight... .SYNOPSIS... Low pressure will develop over Lake Michigan today and then move northeast through the central Great Lakes. Meanwhile, the low will deepen and force a warm front to lift northeast across the area early this afternoon. A cold front will move east across the local area late tonight and Wednesday morning. High pressure will build northeast out of the Central Plains states to Pennsylvania by Wednesday night. Another low pressure system will move northeast to James Bay by Thursday night forcing a cold front east across the area Friday. && .NEAR TERM /THROUGH WEDNESDAY/... The main concern with this forecast update is the increased tornado potential for northwestern Ohio late this afternoon into tonight. Shear dynamics are very good especially the low level shear with a deep layer moisture field over the area. The only limiting factor is instability but current thinking that there is enough low level CAPE and shear that we will see low top convection with spinning showers/storm potential a few tornadoes may be possible especially west of I-71 late this afternoon into this evening. This threat will turn into more of a damaging wind threat late this evening and overnight as the low level jet kicks in across Ohio. No other changes have been made with the ongoing forecast. Previous Discussion... Second round of showers pulling out to the east at this time. Convection, as expected continues to develop over Indiana and will move northeast across the area. Will stick with isolated thunderstorms since convection appears to be weakening as it moves east. Rest of the area will see next round of showers and thunderstorms move east across the area this morning. Made minor adjustments to temperatures. Large amplitude upper level ridge will build east into the eastern Pacific Ocean forcing vigorous upper level trough to dive into the mid section of the United States. This in turn will cause ridging to amplify over the east coast through tonight. The upper level trough will become somewhat negatively tilted by tonight and this will cause surface low pressure to increase in intensity as it tracks northeast into central Ontario, Canada. Warm air will continue to push northeast out of the Gulf of Mexico with a strong support of deep moisture from the Gulf as well. Surface high pressure will begin to build in from the west with much drier and cooler air Wednesday. In the mean time, large area of rain over the eastern half of the area will continue to advance northeast and out of the region. Models suggest some destabilization will take place over the western portions of the area during the next few hours as reinforcing warm front and this air will advance east through the morning hours. begins to lift north. This trend will support the threat for thunderstorms from west to east during the day today. Latest radar and lightning detection systems indicate thunderstorms will continue to develop in the more unstable air over Indiana and advance northeast today. Main concern today will be the proximity of the warm front to the local area. Nose of the low level jet will push northeast into the local area by this evening. 925 MB winds alone reach 45 knots over northern Ohio and western Lake Erie. Hodographs support the possibility for tornadoes; especially in the western third of the forecast area. But, main threat will be strong damaging winds in thunderstorms. As the cold front approaches, the threat for showers and thunderstorms; some possibly severe, will move east into the area this evening. Front is not expected to push east of the area until late Wednesday morning. There is a diminishing threat for thunderstorms toward Wednesday morning just ahead of the cold front. Temperatures will remain mild today and tonight in the warm sector and then drop back a tad for Wednesday post cold front. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... By the start of the short term the entire area will be dry as high pressure begins to build over the region. The high will dominate through the end of the workweek and will see dry weather persist into the weekend. Thursday will be a cool day but the area should rebound to near normal for Friday. && .LONG TERM /SATURDAY THROUGH MONDAY/... Not many changes to the long term today. Models still struggling to determine where a stalled front will set up over the weekend. Best guess right now is that it will be somewhere near Lake Erie which means precip chances late Saturday through early Sunday will be at the northern end of the area. The front will eventually push south of the area on Sunday and have removed all mention of rain from the forecast. Better chances for precip will occur later Monday into Monday night as a wave approaches from the west. Saturday and Monday will see seasonable high temperatures but Sunday will be cool. && .AVIATION /12Z Tuesday THROUGH Saturday/... Little to no improvement in ceilings expected through this forecast period. Showers continue to move off to the east with the first batch of rain. Next batch of showers and embedded thunderstorms will move northeast into the area this morning. Warm front will lift north of the area early this afternoon and will aid in making the atmosphere more unstable and increase threat for thunderstorms. Some thunderstorms will be severe with damaging winds and large hail. Can`t rule out possibility for a tornado; especially west half of the area. Cold front will move through late tonight and Wednesday morning and improving conditions expected behind the front. OUTLOOK...Non-VFR across NE OH/NW PA Wednesday into Thursday. && .MARINE... Winds at the Erie Airport continue to gust to 30 knots but buoy reports just offshore show winds of no more than 20 knots. West of Erie winds along the shore are generally no more than 15 knots although I suspect they may be a tad higher further out. Winds will continue to slowly diminish this morning and will let the small craft expire at mid morning. South to southwest flow generally no more than 15 knots will then continue till a cold front arrives late tonight and Wednesday morning. The front should be east of the lake by 18z. Northwest flow behind the front should be strong enough for more small craft headlines. Winds will quickly diminish Wednesday night as a ridge builds across the lake. Light southwest flow is expected both Thursday and Friday. Another weak boundary will sag south across the lake Friday night causing the flow to briefly return to a northerly direction. The front will stall just to the south on Saturday with the flow becoming light and variable. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...Small Craft Advisory until 10 AM EDT this morning for LEZ142>149. && $$ SYNOPSIS...Lombardy NEAR TERM...Griffin SHORT TERM...Kubina LONG TERM...Kubina AVIATION...Lombardy MARINE...Kubina is the U.S. government's official web portal to all federal, state and local government web resources and services.