textproduct: Cleveland

WHAT HAS CHANGED

No significant changes from previous forecast.

KEY MESSAGES

1) Patchy dense fog possible again tonight, particularly across Northwest Pennsylvania.

2) Above average temperatures expected through Friday before falling near to below normal for the weekend. With the increased temperatures, the remaining snow pack will melt providing a minor risk in river rises and ice jams.

3) Periodic precipitation expected this week. Wednesday will have the highest potential for rain showers with another chance on Friday. Rain/snow mix possible this weekend with a colder air mass over the region.

DISCUSSION

KEY MESSAGE 1... Patchy dense fog may develop again overnight tonight as high pressure continues to build east across the region where saturated low levels persist. Latest HREF guidance shows probabilities of 1/2 mile or less visibility ranging between 40-50% areawide with locally higher probabilities 70-90% across Northwest Pennsylvania.

KEY MESSAGE 2... Upper level ridge will build across the eastern CONUS through the week. Persistent southerly to southwesterly flow will lead to 850mb temperatures rising to +5C to +8C across the region, roughly the 90th to 95th percentile when compared to climatology. A prolonged period of above average temperatures is anticipated beneath this upper level ridge with daily highs in the low to mid 50s Monday and Tuesday. A warm front lifts across the region Wednesday morning leading to highs in the upper 50s to lower 60s by Wednesday afternoon. For reference, average temperatures in mid to late February are generally in the upper 30s to lower 40s. Highs remain above normal Thursday and Friday before dropping back down near to below normal this weekend behind a cold front.

This extended period of above normal temperatures may lead to localized impacts due to the melting of the existing snow pack and ice jams. Will continue to monitor the potential for ice jams over the next few days.

KEY MESSAGE 3... Multiple periods of showers will continue through the forecast period. A weak shortwave aloft pushes across the Great Lakes region which may bring some light rain showers to a portion of the forecast area tonight. Any slight chance to chance PoPs will be confined to Northeast Ohio and Northwest Pennsylvania. QPF will be negligible.

A series of low pressure systems will track across the Great Lakes and Ohio Valley regions Wednesday through the weekend providing multiple chances for precipitation. The first system arrives on Wednesday and will lift a warm front northeastward across the local area. Precipitation on Wednesday will remain as all rain given the warm temperatures aloft and at the surface behind the warm front. Can't rule out a rumble of thunder and gusty showers as surface based CAPE values rise to the 250-500 J/kg range and a strong LLJ 40-45 knots moves overhead Wednesday morning through Wednesday afternoon. Initial push of rain showers exits late Wednesday night with a dry window expected through Thursday evening.

Another low pressure system arrives from the southwest on Thursday night and will move across the local area through Friday. The region will remain in the warm sector which will keep the p-type as all rain before the cold front swings through Friday night. Still some uncertainty in the placement of the next system for the weekend, but a cooler airmass in place will lead to any precipitation that occurs to fall as a rain/snow mix.

AVIATION /18Z Monday THROUGH Saturday/

It is tricky aviation forecast for terminals across the area today as a surface high continues to drift east with an approaching surface trough tonight. Conditions this afternoon have generally improved from this morning, however many terminals are still experiencing non-VFR visibilities and ceilings. As winds increase from the southwest this afternoon, more mixing sure occur, further improving conditions. Cannot rule out patches of dense fog however, especially across southeastern counties where visibilities could remain below 1SM for much of the day. Tonight, there is once again a chance of fog across the area, presenting another period of non-VFR conditions. Confidence is not very high in how extensive this fog will be given mid-level clouds pushing east and elevated winds, so capped diminished vsby's at 2SM for now.

Winds this afternoon from the southwest at 10-12 knots will calm to 5 knots or less tonight into Tuesday.

Outlook...Non-VFR conditions possible on Tuesday afternoon. Additional non-VFR conditions possible Wednesday and Thursday night into Friday in rain showers.

MARINE

Lake Erie continues to remain ice covered. According to GLERL, there is a swatch of ice just east of the Lake Erie Islands that is much thinner than the rest of the ice.

Winds across Lake Erie will gradually increase tonight from the southwest to 10-12 knots before remaining calm on Tuesday. A more notable increase in winds will occur on Wednesday as a warm front lifts north. Winds from the south-southwest are expected to increase to 20-25 knots. Winds will briefly weaken before once again becoming elevated late Thursday into Friday. In addition to the increased winds, a prolonged period of above average temperatures (and temperatures above freezing) will begin to deteriorate the ice sheet. As a result, ice will become more fragile and more prone to ice floes. It is critical that people remain off of the ice on Lake Erie this week! Shifting ice can result in persons becoming stranded and current shipping lanes becoming closed.

In addition to the primary concern of the ice, there is a chance of patchy dense fog tonight across portions of the lake, but given low confidence have opted not to issue anything at this point.

CLE WATCHES/WARNINGS/ADVISORIES

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