323 FXUS61 KCLE 061214 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 714 AM EST Fri Dec 6 2019 .SYNOPSIS... A weak clipper system will move through the Great Lakes region today and exit off the New England coast tonight. High pressure will return to the area for Saturday and remain under its influence through Sunday. An area of low pressure will develop over the southern Plains on Sunday night and extend a warm front into the area for Monday. This low will move northeast along the warm front and enter the Great Lakes region for Monday night, extending an associated cold front across the area on Tuesday. && .NEAR TERM /THROUGH SATURDAY/... Tough to update the forecast this morning as temperatures across the forecast area vary greatly with localized temperature gradients from the mid 30s to mid to upper 40s. High temperatures will be achieved today this morning before the cold frontal passage later this afternoon. Some precipitation has developed along the lakeshore with some light rain in the Erie area. Expect a little bit better coverage this morning in this area as the front approaches and have a brief window of likely PoPs for Erie County PA. Previous Discussion... A weak clipper system is sliding through the northern Great Lakes this morning and will continue east-southeast through Upstate New York this afternoon and eventually off the New England coast this evening. This system will miss the area well to the north during the daytime hours and any precipitation will be with the associated cold front with some help from Lake Erie in the snow belt region. With that, have dialed back PoPs for today from categorical to just a mix of slight chance to chance for NE OH and NW PA. Temperatures today will get into the 40s ahead of the front before falling with the cold frontal passage. With warm temperatures trapped close to the surface, expecting any early precipitation to be more rain than snow with some mix closer to the front. Once the clipper and cold front pass to the east, lake effect processes will attempt to set up over the region as 850 mb temperatures settle into the -8 to -10 C range. Recent trends are that it will take a few hours for the atmosphere to re-saturate behind the cold frontal passage and lake effect snow will have trouble developing until the evening hours and so have highest PoPs around 00z with a brief period of likely snow. Dry air surges in quickly Friday night and snow should be done by day break on Saturday morning. Snow accumulations look low as snow will be scattered in nature with perhaps an inch of snow possible in the hills of Erie County, PA. High pressure builds into the region on Saturday and will keep the area dry, while cooler air remains over the region. Temperatures will struggle to approach normals in the upper 30s on Saturday. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... Surface high pressure will be located over Pennsylvania Saturday evening, building to the Mid-Atlantic Coast by Sunday morning. Winds will start out nearly calm in eastern areas Saturday evening but a light southerly wind will develop through the overnight. Passing mid and high cloud expected at times on Saturday night, giving way to an expanding stratus deck on Sunday. A warm front lifts north across the area on Sunday as low pressure tracks out of the northern Plains towards Hudson Bay. Despite the cloud cover, southerly flow and warm advection will result in highs on Sunday approximately 10 degrees warmer than Saturday. Southerly flow ahead of the trough developing over the Plains will also result in good moisture advection, especially Sunday night into Monday. Showers will expand in coverage Sunday night with widespread rain expected on Monday as another wave of low pressure tracks northeast along the frontal boundary. Much of the area can expect to see rainfall amounts of around a half inch with above normal temperatures in the low 50s on Monday. && .LONG TERM /TUESDAY THROUGH THURSDAY/... A deep upper level trough will develop over the Plains on Monday night, swinging eastward across the Great Lakes Region through Tuesday night. A strong cold front will move east across the area on Tuesday with temperatures falling through the daytime hours as an arctic airmass arrives. 850mb temperatures are expected to reach between -17 to -20C by Wednesday morning. At this time long range models continue to show a favorable set-up for westerly flow across Lake Erie from Tuesday evening through Wednesday evening. As previously noted, moisture depth is limited but good convergence down the long fetch of the lake coupled with extreme instability over the relatively warm lake waters presents the potential for heavy lake effect snows to develop, especially closer to the lakeshore. We will need to monitor model trends into next week as some slowing of the system is likely and slight adjustments in wind direction will alter the favored areas for snowfall. Highs on Wednesday could be 20 or more degrees below normal in the 20s trended the forecast temperatures towards the cooler ECMWF MOS guidance. && .AVIATION /12Z Friday THROUGH Tuesday/... VFR conditions with mid-level clouds remain over the region ahead of a surface cold front currently stretching from north of KDTW to just northwest of KFWA. This front will progress southeast this morning, crossing much of the airspace by this afternoon. Ahead of the front, some precipitation was developing along the Lake Erie lakeshore around KERI and some rain or wet snow will be present through the cold frontal passage. As the front crosses the area, ceilings will lower with MVFR expected at several locations. Winds will veer with the front to the west then northwest through the TAF period. Some lake effect snow is possible around the KERI and perhaps KYNG areas tonight. Dry air enters the region quickly overnight and all locations should be VFR for the first part of Saturday. .OUTLOOK...Non-VFR likely late Sunday through Monday with rain. Non-VFR across the snowbelt into Tuesday. && .MARINE... Low pressure will pass north of Lake Erie this morning pulling a cold front south across the lake behind it. A Small Craft Advisory has been issued from Cleveland eastward as the flow shifts to the northwest at 15 to 25 knots behind the front. Waves of 4 to 6 feet can be expected this afternoon into tonight. Strong high pressure will build east across the region on Saturday, reaching the East Coast on Sunday. Southerly winds will increase into the 15 to 25 knot range on Sunday and remain breezy into Monday. A strong cold front will move west to east across Lake Erie on Tuesday ushering in an arctic airmass. Westerly winds of at least 20-25 knots can be expected behind the front with Small Craft Advisories likely during the mid-week period. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...Small Craft Advisory from 10 AM this morning to 4 AM EST Saturday for LEZ146>149. && $$ SYNOPSIS...Sefcovic NEAR TERM...Sefcovic SHORT TERM...KEC LONG TERM...KEC AVIATION...Sefcovic MARINE...KEC