textproduct: Cleveland

WHAT HAS CHANGED

QPF has continued to trend down today, with most areas only seeing light to moderate rain.

KEY MESSAGES

1) Widespread rain early this morning will give way to scattered showers late this morning through the afternoon before ending from NW to SE. Most areas will only see 0.25 to 0.75 inches of rain.

2) Dry weather and continued below normal temperatures expected Tuesday and Wednesday before periodic rain chances return Thursday through the weekend along with a warming trend.

DISCUSSION

KEY MESSAGE 1... The latest Infrared satellite and water vapor loops show the mid/upper shortwave trough axis now crossing the western Great Lakes, with RAP analysis placing the surface low over southern Indiana. Broad warm air advection and isentropic ascent to the north of the associated warm front extending east from the low has been driving a shield of light rain, but it has struggled to efficiently reach the ground all night. This is due to both an abundance of low-level dry air and the best synoptic support displaced just to our north. RAP analysis shows an 80+ knot H3 jet streak crossing Lake Erie on the southeast flank of the shortwave early this morning, so the greatest forcing for ascent beneath the left exit of that jet streak has been over southern Lower Michigan and southern Ontario. This has set up the strongest mid-level frontogenesis band over that area, and regional radar loops support this in showing the higher reflectivity bands up that way.

Despite the best forcing displaced to the north, a fairly steady light rain will continue through sunrise driven by the warm air advection and isentropic ascent until a dry slot moves in from SW to NE. As the low progresses ENE across northern Ohio late this morning through the early afternoon, the trailing cold front will slowly sag through the area. The RAP and other hi-res guidance depict better upper jet support as the trailing front sags south, and weak instability should combine with this to generate some heavier convective showers late this morning through the afternoon. Would not be surprised if some areas see slightly better rainfall with this cold frontal round compared to the early morning round due to the convective elements, but overall, continued to lower QPF significantly from previous forecasts. Most areas will only see 0.25 to 0.75 inches by this evening as the lingering showers end from NW to SE. The clouds and showers will keep temperatures very cool today, with highs in the upper 60s/low 70s.

KEY MESSAGE 2... Canadian high pressure will build down across the Great Lakes in the wake of this system tonight and Tuesday and eventually settle over the Ohio Valley by Wednesday. This will support dry conditions and plenty of sunshine, but a continuation of broad mid/upper troughing across much of the northern tier of the CONUS will keep temperatures below normal

The pattern will become active again starting Wednesday night and Thursday as a mid/upper shortwave drops through the broad longwave trough and pushes a weak cold front into the region. The amount of moisture return ahead of this front is uncertain since the troughing will keep the main pool of higher PWATs and instability shunted well to our south, but the pattern seems to support the idea that the front will become quasi-stationary across the Ohio Valley region late Thursday into the weekend as it becomes aligned parallel with the west-east flow on the southern edge of the broad trough. The front in the vicinity and multiple shortwaves dropping through the trough will allow for periodic showers and thunderstorms from late Wednesday night through the weekend. At this point, it looks like the greatest coverage will be with the initial frontal passage Thursday then again Saturday as a stronger shortwave drops through the Great Lakes. Temperatures will gradually warm Thursday through the weekend but will remain a little below normal until a better surge of warmth and humidity potentially arrives Sunday in response to a ridge building upstream over the Mississippi Valley.

AVIATION /12Z Monday THROUGH Friday/

As low pressure moves into western Pennsylvania this morning, the steady rain is shifting eastward with it. Portions of northwest and north central Ohio will experience drizzle or intermittent showers as a front is pulled south behind the low. IFR ceilings have also expanded on the northwest side of the low pressure system and will persist through mid-afternoon. Some daytime heating is expected to enhance showers moving southeast across the area this afternoon in the 17-20Z window and may impact MFD/CAK/YNG. Isolated thunder can not be ruled out but probabilities are too low to include. Stratocu clouds will erode from the northwest towards this evening with the potential for stratus to develop as clouds clear. This seems more likely in Northeast Ohio and Northwest Pennsylvania where IFR ceilings may return. Northeast winds of 8-12 knots will back to the north and may gust to around 20 knots near TOL/CLE/ERI. Winds will decrease tonight as the low pulls away and high pressure builds in from the north.

Outlook...Non-VFR continues into Monday night with low ceilings. Non-VFR possible again in rain showers Wednesday night through Thursday night.

MARINE

Northeast winds will ramp up to 20-25 knots on Lake Erie today as low pressure tracks from Central Ohio east into Pennsylvania. Waves will build to 4 to 8 feet with onshore flow. Small Craft Advisories and Beach Hazards are in effect through 4 PM west of the Lake Erie Islands and 10 PM east of the Islands. North winds will decrease tonight as the low departs and high pressure strengthens over the Great Lakes.

The next low pressure system will pass north of Lake Erie on Thursday with a cold front stalling just south of the lake on Friday. Southwest winds of 10-15 knots will veer to northwesterly but look to remain at 15 knots or less.

CLE WATCHES/WARNINGS/ADVISORIES

OH...Beach Hazards Statement until 4 PM EDT this afternoon for OHZ003-007. Beach Hazards Statement through this evening for OHZ009>011. Beach Hazards Statement through this evening for OHZ012-089. PA...Beach Hazards Statement through this evening for PAZ001. MARINE...Small Craft Advisory until 4 PM EDT this afternoon for LEZ142- 143. Small Craft Advisory until 10 PM EDT this evening for LEZ144>146. Small Craft Advisory until 10 PM EDT this evening for LEZ147>149.