textproduct: Cleveland

WHAT HAS CHANGED

With this update, opted to add a slight chance of showers to western counties tomorrow as forcing associated with a weak boundary moves into the area.

KEY MESSAGES

1) High pressure will continue to drift east through Tuesday with gradually warming temperatures. Light, scattered rain showers are possible Monday across the western counties.

2) Confidence is increasing that a strong low pressure will impact the region midweek, resulting in widespread rain showers Wednesday and Thursday.

DISCUSSION

KEY MESSAGE 1... High pressure will continue to influence the area as it slowly drifts towards the Mid-Atlantic Coast through Tuesday. With the area now on the backside of the aforementioned high pressure, overall flow will become more southerly allowing for an increase in both moisture and warmer air across the area. Highs today and tomorrow will climb into the upper 60s to low 70s before really warming into the mid 70s on Tuesday. As the area transitions to this southwest flow, conditions should remain dry today. However, late tonight through Monday there is a mid-level push of energy that is expected to move northeast through the area which could provide enough support for some isolated shower development across western counties. At this point not expecting anything widespread or any heavy rain showers, however wanted to make note of the change given previous forecasts were dry through Tuesday. By Monday night, the axis of mid-level energy should push east, allowing for conditions to dry out through Tuesday. No matter what, given the proximity of the area to the departing high and approaching low pressure, mostly cloudy skies are expected to stick around.

KEY MESSAGE 2... The end of this prolonged period of dry weather looks to be in site as confidence continues to increase that widespread precipitation will impact the area Wednesday and Thursday. Behind the departing high pressure discussed prior, a deepening upper level trough and associated low pressure system over the north-central US is expected to track east towards the Great Lakes region. Models are slowly beginning to agree on the overall timing of the system through Thursday, which essentially keeps the surface low over the region and moves multiple boundaries east. This couples with strong upper level support from the trough and an open stream of moisture from the Gulf should result in multiple rounds of showers in the middle of the week. The biggest uncertainty now is the progression of the system once it reaches the region. Models have now begun to slow the progression of this low, nearly stalling it over the region as the overall pattern becomes less amplified. If this does occur, the potential for showers could extend past Thursday possibly even lingering into the weekend.

At this point, there are no flooding concerns with this precipitation as it should be slow and steady limiting the localized runoff from the dry antecedent conditions. In addition, given the increasing temperatures into the mid 70s, cannot rule out a few rumbles of thunder on Wednesday and Thursday, although overall instability looks to be marginal given the expected cloud cover and decreasing daylight hours. Temperatures through next weekend are expected to remain above normal.

AVIATION /06Z Sunday THROUGH Thursday/

High pressure east of the area will allow for VFR conditions to continue across the airspace with mid-level ceilings. Winds will start from the east to southeast and shift to the south as warmer air surges into the region. Some spotty showers will be possible today and tonight with the warm air advection in the region but probability of precipitation at a terminal is extremely low and would likely not have any operational impact.

Outlook...Non-VFR possible in rain on Wednesday and Thursday.

MARINE

A high pressure system will continue to slowly drift towards the Mid- Atlantic Coast through Tuesday. This will result in south-southwest winds of 5-10 knots to continue through Monday before increasing Monday night to 10-15 knots from the south. These winds will be consistent through Tuesday, allowing for waves along the southern lakeshore of Lake Erie to remain 2 feet or less. By Tuesday night, the aforementioned high will drift off the coast as a low pressure system over the north central US tracks into the region. This robust system will increase the gradient over the area and increase winds from the south-southwest to 12-18 knots. Given the offshore flow, waves should remain between 1-3 feet at most through at least Thursday. Confidence begins to diminish as models diverge in handling the progression of this low at the end of the week and into the weekend with some models suggesting the aforementioned low nearly stalls over the region. Will have to continue to monitor the progression and any potential marine headlines needed.

CLE WATCHES/WARNINGS/ADVISORIES

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