textproduct: Cleveland

WHAT HAS CHANGED

Confidence continues to increase in wet and warm conditions Tuesday onward.

KEY MESSAGES

1) Light snow continues through the pre-dawn hours this morning across Northeast Ohio and Northwest Pennsylvania. Limited impacts are expected.

2) A brief period of freezing rain is possible Tuesday morning, though confidence remains low.

3) Warmer conditions with multiple rounds of rain are expected Tuesday through next weekend, bringing the potential for nuisance flooding and rising water levels on area rivers and creeks.

DISCUSSION

1) A quick round of light snow continues through the pre-dawn hours this morning, mainly east of I-77 . Dry-low levels did prevent snow from beginning until around 11 PM - 12 AM, which is likely to lower overall snow amounts. There are a few spots with road temperatures at or below freezing, mainly in Lake/Ashtabula Counties, and Northwest Pennsylvania. Outside of these areas, snow will struggle to stick to pavement, limiting any road impacts. Any snow that does stick won't last long as it melts with sunny skies. Snow accumulations of a half inch or less are expected.

2) An upper-level trough and associated surface low move to the lee of the Rockies Monday night into Tuesday, with a warm front lifting north towards our area in response to broad south to southwest flow ahead of the trough/low. Precipitation is likely to develop upstream in response to isentropic lift and frontogenetical forcing, with the precipitation shield moving northeastward across the area Monday night into Tuesday. A warm nose aloft ahead of the surface front may produce a vertical thermodynamic profile briefly favorable for freezing rain, particularly along the leading edge of the advancing precipitation.Surface temperatures ahead of the warm front will be below freezing, though only marginally so.

Confidence in freezing rain is low at this point. It is very dependent on the location/timing of the warm front, which will impact surface temperatures. Meanwhile, there is also some uncertainty with precipitation location/timing. Northwest Pennsylvania has the best chance at seeing a glaze of ice, which is where there's likely to be the best overlap of cold surface temperatures and precipitation. Freezing rain could also be possible in Northeast Ohio (uncertainty with temperature) and Northwest Ohio (uncertainty with precipitation). We should start to have a better idea once we get into range of hi-res guidance (12Z cycle on Sunday will be in range). Where freezing rain occurs, a light glaze could make thing slick before temperature warm up to the 40s and 50s by the afternoon.

3) A strong upper-level ridge anchored off the southeast Atlantic coast will provide sustained southwest flow of warm, moist air to much of the eastern CONUS through at least this weekend (and probably into much of the following week too). Meanwhile, a warm front wavering over the area and several upper-level trough will be the focal points for several periods of rainy weather. A few specific points worth mentioning regarding this period: -Confidence is very high in multiple rounds of precipitation and warm weather continuing through at least the weekend, though some uncertainty regarding the exact details. -Confidence is low in flooding and associated impacts. It's likely we see at least nuisance flooding (i.e. ponding near curbs, standing water in parking lots/yards, minor basement seepage, or flooded parks from high water levels on rivers/creeks) but there is some uncertainty in higher impacts. -The best chance for thunderstorms will be Wednesday night and again Friday. Convection could lead to locally heavy rain and higher QPF/flooding potential. -Friday has the best overlap of surface-based instability and deep-layer shear, and consequentially, a low chance for severe weather. -Friday is likely to be the warmest day of the forecast, and could challenge record daily highs.

AVIATION /06Z Sunday THROUGH Thursday/

The main aviation concern for potential weather impacts will be overnight with areas of light snow moving in. Mostly TAF locations have MVFR to VFR conditions and ceilings as of late this Saturday evening. We expected ceilings to lower to MVFR to lower end MVFR for most locations tonight through Sunday morning. The best potential for IFR conditions will be at ERI with 1sm to 2sm snow with ceilings down to 1500 feet for a few hours between 06z and 09z. We have mentioned PROB30 or TEMPO groups for the rest of the TAF sites for possible 3sm to 5sm light snow and ceilings between 1500 and 2500 feet later tonight into Sunday morning. Conditions will improve late Sunday morning to VFR ceilings through Sunday afternoon/evening.

Winds will be from the north-northeast 8-12 knots through Sunday afternoon. There will be a few gusts of 20 to 25 knots through about 09z overnight.

Outlook...Non-VFR possible in snow again Sunday night into Monday, mainly along and south of US-30. Periods of non- VFR conditions are possible throughout next week as an active pattern becomes established.

MARINE

Elevated northerly flow 10-20 knots early this morning will diminish throughout the day today to 5-10 knots while becoming easterly. Flow will briefly shift offshore on Tuesday before returning easterly to northeasterly Tuesday night and Wednesday. A more prolonged period of primarily offshore flow 10-15 knots is expected Thursday into the weekend.

An extended period of mild temperatures accompanied by multiple systems moving through the region will lead to continued shifting and decay of remaining lake ice.

CLE WATCHES/WARNINGS/ADVISORIES

OH...None. PA...None. MARINE...None.