textproduct: Cleveland

WHAT HAS CHANGED

Increasing POPs in coverage tonight in mid level isentropic lift that will become more pronounced over the eastern half of the CWA, but in coverage only.

KEY MESSAGES

1) Prefrontal PVA brings a chance for storms Monday ahead of the cold front that drops into the CWA from the northwest on Tuesday.

2) Dominant upper level troughing reclaims its hold on the Great Lakes and brings temperatures back below normal for the end of the week and into the weekend.

DISCUSSION

KEY MESSAGE 1... PVA aloft in the 500mb flow will utilize the MLCAPE available Monday for sparking convection across the CWA. This will occur as higher dewpoints advect in from the west and low level jet enters the region with a 50kt streak 00Z Tuesday. For now, the Day 2 convective outlook has the western half of the CWA in the Marginal risk category for the severe potential. As the cold front approaches the region from the northwest, waves of low pressure will develop along the cold front. This will result in a reduced forward speed of the boundary as it moves into the CWA and a longer residence time heading into midweek. With multiple rounds of convection now expected in association with this frontal boundary, Tuesday has a marginal risk for excessive rainfall for much of the CWA with a now consistent influx of low level moisture in southwesterly flow. For the duration of the event into late Tuesday, should easily see 1-2 inches of rain for portions of the CWA, especially where the first day convection occurs as this storm total will take into account the Monday into Monday night activity.

KEY MESSAGE 2... System finally exits late Tuesday night with more cold air advection dominating the picture and a broad upper level trough returning to the Great Lakes. Temperatures from Monday will drop 15-20F area wide back to below normal values, the trend of the region since the last week of April. The trailing upper level trough axis gives another chance for showers in the cold pool Thursday, and then again with more PVA aloft for early Friday. Drying for the first part of the weekend. Will possibly be looking at more frost/freeze headlines for the Thursday night time frame with lows in the 30s. Temperatures slowly moderate back into the 60s primarily for Saturday.

AVIATION /18Z Sunday THROUGH Friday/

Aloft, W'erly to NW'erly flow and embedded shortwave ridges and troughs affect our region through 00Z/Tues. Variable amounts of mainly mid/upper-level cloudiness will precede each shortwave trough axis. At the surface, a ridge continues to exit slowly E'ward. Our regional surface winds trend S'erly to SW'erly around 10 to 20 knots through the TAF period. These winds will gust up to 20 to 30 knots at times, especially before 01Z/Mon and between ~14Z/Mon and ~23Z/Mon. Note: diurnal cumuliform clouds with bases near 7kft AGL are expected to dissipate by ~00:30Z/Mon, but then redevelop with bases near 5kft AGL after ~14Z/Mon.

Mainly dry weather and VFR are expected through the TAF period. However, a SW'erly low-level jet of about 35 to 45 knots at/near 925 mb should develop over our region between ~04Z/Mon and ~12Z/Mon and yield low-level wind shear at all TAF sites in northern OH and NW PA. Moist ascent associated with this low-level jet will cause scattered stratocumuli with bases near 6kft AGL to blossom over our region. These stratocumuli may produce isolated rain showers with brief MVFR, but confidence in these showers impacting any of our TAF sites remains low. After ~20Z/Mon, isolated to scattered rain showers and thunderstorms associated with the aforementioned shortwave troughs aloft and attendant surface trough axes should enter northern OH from the WSW and develop over northern OH and perhaps NW PA. Brief MVFR to LIFR and brief/erratic surface wind gusts up to 30 to 50 knots are expected with these showers and especially storms.

Outlook...Periodic rain showers with non-VFR are expected Monday night through this Friday. Occasional thunderstorms are forecast, especially Monday night and again Tuesday afternoon through evening.

MARINE

West-southwest winds of 10-20kt are ongoing this afternoon, with wind gusts of 25-30kt across the nearshore waters. Winds will briefly lull early this evening, before sustained winds increase to 15-25kt across the entire lake overnight tonight as a stronger low-level jet and tighter pressure gradient move across the lake. Waves of 1-3/2-4 feet in the nearshore waters and 4-7 feet in the open waters are expected through early Monday. Small Craft Advisories will be out for all nearshore waters through 8 AM Monday to account for the brisk southwest winds with the full afternoon forecast update. Winds decrease to under 20kt during the day Monday, though increase a bit again Monday night into early Tuesday ahead of an approaching cold front. Another round of Small Craft Advisories may be needed. A cold front moves south across the lake on Tuesday, with winds whipping around to the north behind it and subsiding into Wednesday.

CLE WATCHES/WARNINGS/ADVISORIES

OH...None. PA...None. MARINE...Small Craft Advisory until 8 AM EDT Monday for LEZ142>149.