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/

It will be a mostly sunny/clear and VFR afternoon. A period of mid-level clouds and perhaps a few showers is expected overnight tonight along and ahead of a warm front that will lift across the area early Monday. Expanded the VCSH mention to much of Northeast OH and Northwest PA, though confidence in any impacts to a given terminal remains low...brief non-VFR vsby is possible with a few showers. Otherwise, conditions remain VFR into Monday with potential for scattered showers/storms to move in from the southwest after 18z Monday. Began including VCSH at CLE who has a 30 hour TAF, other sites will need evaluated as the shower/thunder potential moves into their TAF period.

Southwest winds of 10-18kt with gusts to 25kt continues this afternoon. Winds shift more southerly and will try losing their gustiness this evening. A 40-45kt low-level jet (at 1500-2000 feet) moves west-east across the area between ~5-13z Monday, introducing low-level wind shear potential. Expanded the wind shear mention to all TAFs except for ERI, where the low-level jet will be a bit more marginal and arrive close to sunrise. Wind shear quickly subsides Monday morning as mixing improves after sunrise and as the low-level jet subsides/exits east. Southwest wind gusts to 25kt are likely Monday afternoon.

Outlook...Non-VFR possible in scattered showers and thunderstorms Monday afternoon/night followed by increasing coverage of precipitation Tuesday afternoon and night and again on Thursday.

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>145- 147>149.