Area Forecast Discussion
Issued by NWS Cleveland, OH

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000 FXUS61 KCLE 170455 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 1155 PM EST Thu Nov 16 2017 .SYNOPSIS... A trough will finish crossing the eastern Great Lakes this evening. High pressure will build overhead for later tonight and Friday. A warm front will lift north early Saturday morning with the low center tracking across northern Indiana and across Lake Erie during the day. A strong cold front will follow Saturday evening. High pressure will build across the lower Ohio Valley late Sunday and across the upper Ohio Valley Monday. && .NEAR TERM /THROUGH FRIDAY NIGHT/... Update...Previous forecast remains on track. Only made minor adjustments to the hourly temperature grids. Original Discussion... Trend for this evening will be for the scattered light showers/drizzle across north-central OH east to nw PA to diminish and come to an end closer to midnight. This is as a trough across the eastern lakes exits taking with it the deeper moisture and the ridge begins to build in from the west. Up to this point only a few wet flakes have mixed in with the rain. This will continue to be possible this evening, but any accumulation would be hard to come by. Others will keep the cloudy skies with breaks limited. Feel the stratus will be hard to get rid of tonight and most will likely have to wait until tomorrow and a south flow to scour it out. Temperatures today have been holding in the upper 30s/lower 40s. Only expecting a drop to just below freezing tonight which is slightly warmer than guidance due to the cloud cover forecast. Quiet weather day Friday with high clouds expanding and thickening. Highs in the 40s. Southerly flow increases Friday night. Rain will rapidly expand across the area with a significant amount of moisture transport and arrival of upper support. Lows will be early in the evening with the rising temperatures going into Saturday morning. Kept the mention of thunderstorms with some elevated instability. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... A fairly compact upper level trough moving east across the CONUS will become negatively tilted over the Great Lakes Region by Saturday evening. Low pressure tracking out of the Plains will deepen as it moves northeast to near Lake Erie by 00Z Sunday, then rapidly deepens overnight as it continues northeast into Sunday. A strong 55-65 knot low level jet will move overhead on Saturday, with a warm front lifting north across the area. Widespread rain is expected on Saturday with the front and will continue with a chance of thunderstorms with some elevated instability. A strong inversion will prevent the stronger winds aloft from mixing down although breezy conditions are expected. Locally stronger winds are possible at Erie, PA where downsloping may result in wind gusts to 40 mph or higher. The temperature forecast is difficult on Saturday with warm advection offset by rain. Kept highs in the upper 50s but could be warmer in some sites, especially if sizable breaks in the rain occur in the south. Convection is not expected to become surface based but that is something to watch. A strong cold front sweeps east across the area Saturday evening with temperatures falling quickly behind the front. Gusty winds of 30 to locally 40 mph are expected along the front. Precipitation will linger in the east overnight as the low continues to deepen while tracking towards Quebec. Rain will transition to snow although accumulations will be limited by warmer flow off the lake and the wet ground. The forecast includes around an inch of accumulation over the higher areas in northwest PA. Will continue to evaluate timing of the rain to snow transition and adjust forecast as needed. Precipitation transitions to lake effect on Sunday as 850mb temps of -10C move across Lake Erie. Despite good low level instability, we lack upper level support with drier air spreading in from the west during the day. There may be upstream contribution from Lake Huron but that is expected to shift east. Enough limiting factors to keep accumulations on the low side and generally focused over the higher terrain in PA. Could see an inch or 2 across inland portions of the Ohio snowbelt with a few inches in NW PA. As the flow backs on Sunday night, will need to watch for some intensification of a westerly band off Lake Erie but confidence is low at this point. Snow showers will become confined closer to the lake on Monday before coming to an end. && .LONG TERM /MONDAY THROUGH THURSDAY/... High pressure will be sliding off the east coast of the US Monday night with warm advection occurring across the County Warning Area. The next cold front will arrive Tuesday afternoon but it appears we will be dry. However lake effect snow will likely develop in the wake of the front Tuesday night into Wednesday. There is uncertainty how long this will linger into Thursday with models differing on how fast high pressure ends the snow. Tuesday will be the warm day of the long term with highs in the middle to upper 40s. Temperatures will drop to below seasonal averages Wednesday into Thursday with highs 35 to 40 degrees. && .AVIATION /06Z Friday THROUGH Tuesday/...
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Dirty ridge centered over the Great Lakes will drift to the East coast by evening. MVFR deck will improve to VFR by late morning then start to scatter out by mid afternoon. OUTLOOK...Non-VFR returns tonight through Saturday in SHRA. Thunderstorms possible late Friday night and Saturday as arctic front moves across forecast area. Rain changes to snow Saturday night. Lake effect snow showers develops in the snowbelt Sunday into Monday.
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&& .MARINE... Winds are starting to decrease on Lake Erie as low pressure over Quebec departs to the northeast. A Small Craft Advisory will remain in effect on the western basin through 10 PM with eastern areas expiring at 4 AM. Winds will drop off quickly late tonight as high pressure over the western Great Lakes expands eastward. Southerly winds will develop as the high shifts to the east Friday. Winds will increase Friday night into Saturday with Small Craft conditions and winds of 20-25 knots ahead of an approaching low pressure system. Low pressure tracking out of the Mississippi Valley will undergo rapid deepening into Saturday night as it tracks northeast into Canada, pulling a strong cold front east across Lake Erie. Gale force winds can be expected with a wind shift to the northwest behind the cold front Saturday night with Small Craft conditions lingering Sunday into Sunday night. We will have to monitor water levels on the western basin of Lake Erie ahead of the front on Saturday. Water levels are forecast to drop to near the critical mark for safe navigation. High pressure will build east across the Tennessee Valley on Monday with winds backing to southwest. Brisk winds expected to continue and Small Crafts may need to be extended. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...Small Craft Advisory until 4 AM EST Friday for LEZ145>149. && $$ SYNOPSIS...Oudeman NEAR TERM...Mottice/Oudeman SHORT TERM...KEC LONG TERM...Mullen AVIATION...DJB MARINE...KEC is the U.S. government's official web portal to all federal, state and local government web resources and services.