textproduct: Cleveland

WHAT HAS CHANGED

Forecast remains largely on track through the 7 day period.

KEY MESSAGES

1) More fog possible again tonight with rain chances becoming more isolated to scattered, followed by a drier period Friday and temperatures increasing as a warm front moves through.

2) Thunderstorm chances on the increase Saturday in the warm sector with increasing low level winds, dewpoints, and an approaching cold front.

3) Drier Sunday and Monday, continued above average temperatures, and another frontal system midweek.

DISCUSSION

KEY MESSAGE 1... As rain lifts northeastward with a warm front that is ever so slowly creeping in the same direction, precipitation will become more isolated to scattered this evening and into the overnight time frame. So there is a drying trend overall to the forecast in the next 24 hours, but without the ability to scour out the saturated near-surface layer of the atmosphere and a stubborn inversion in place, fog and low stratus will likely be an issue once again heading into tonight and could need another Dense Fog Advisory for a third night in a row. A warm front finally makes better headway through the CWA Friday, and temperatures will finally see the increases into the 60s with some low 70s possible in the southern tier.

KEY MESSAGE 2... The first real threat for severe weather this year arrives on Saturday as the SPC has a portion of the eastern CWA outlooked for a Slight Risk. Low level winds will be on the increase in the warm sector ahead of an evening cold front. Meanwhile, dewpoints will be decidedly spring-like with upper 50s and lower 60s expected. This will help with developing instability into the afternoon hours as the aforementioned low level jet strengthens to the 40-50kt range, making winds the primary threat in this case. With 0-6km shear around 50kts, expecting line segments to form ahead of the cold front in the potential severe weather day.

KEY MESSAGE 3... Cold front late Saturday clears the airmass, and knocks temperatures down 15 degrees or so for Sunday, climbing again Monday. Significant warm-up through Tuesday/Wednesday ahead of another potent cold front expected midweek. Out in the forecast quite a ways, but this synoptic setup suggest another convective potential.

AVIATION /06Z Friday THROUGH Tuesday/

A frontal boundary extends from near GKJ-MFD-FDY and is slowly sinking south. Locations south of the boundary have tended to have MVFR visibilities and possibly even VFR ceilings but those are expected to decline quickly through 08Z. Locations north of the boundary have had low IFR conditions with ceilings generally less than 400 feet. Patchy dense fog has been noted but has tended to fluctuate some. We do expect the coverage of dense fog to fill in but later than previously expected, more in the 8-13Z window. Patchy drizzle is also possible in northwest Ohio. The warm front starts to lift north after 12Z which will lead to rapid improvement of conditions.

Winds will be light overnight with less than 6 knots, increasing to the 5-10 knot range out of the south at most terminals on Friday afternoon.

Outlook...Occasional periods of rain through Saturday will bring additional non-VFR conditions.

MARINE

Northeast winds of 10-15 knots across Lake Erie today will persist through much of Friday before a warm front lifts north late Friday into Saturday. Behind the warm front, winds will veer to become southwesterly, increasing to 15-20 knots through Saturday evening. As a surface ridge builds over the area late Saturday, winds will weaken to 5-10 knots before ramping back up Sunday night to 15-20 knots. The active pattern will continue to bring elevated wind speeds periodically across Lake Erie this week. Although the lake remains mostly ice covered, where there are breaks in ice, waves will periodically increase to 2-4 feet. These breaks are primarily observed in the western basin. As temperatures remain above average the next couple of days, the ice thickness and coverage will continue to slowly decrease.

CLE WATCHES/WARNINGS/ADVISORIES

OH...None. PA...None. MARINE...Dense Fog Advisory until 10 AM EST this morning for LEZ142>146- 162>166.