Area Forecast Discussion

WHAT HAS CHANGED

Chances of rain have trended up on Friday and will continue across the snowbelt region of Northeast Ohio and Northwest Pennsylvania on Saturday. Temperatures continue to trend cooler for Saturday.

KEY MESSAGES

1) Rain will spread east across the area through this evening. Many areas can expect a quarter to a half inch of rain with locally higher amounts closer to Central Ohio.

2) Cooler temperatures and showers will arrive behind a front on Friday and linger into Saturday across Northeast Ohio and Northwest Pennsylvania.

DISCUSSION

KEY MESSAGE 1... Low pressure is located over the Upper Midwest with a cold front extending south through the Mississippi Valley. Radar imagery shows a swath of rain ahead of a deep upper level trough that will curl northeast towards the Great Lakes Region today. Rain is forecast to reach the I-75 corridor towards sunrise on the nose of a 45 knot low level jet and expand east today. The deep moisture axis shifts east with time with most areas receiving between a quarter and half inch of rain. Locally higher rain amounts are focused towards Central Ohio. Temperatures will be warmer in the east today where most of the morning will be dry. Looking upstream a broken S type radar signature in Indiana is starting to fall apart as it moves northeast. Fortunately there is little to no surface based instability so this trend is expected to continue with no hazardous weather expected. We will see southerly winds gusting to around 30 mph in Northwest Ohio as the gradient tightens and low level jet arrives. Once the rain arrives fills in the potential for stronger wind gusts will be reduced due to stable boundary layer conditions. Have included just a slight chance of thunderstorms in portions of Northwest and North Central Ohio but so far not seeing any lightning upstream in Indiana.

Rain will tend to exit to the east by Thursday morning as the dry slot sets up overhead. Favorable mixing should help clear clouds out and mix into drier air aloft. High temperatures are forecast to be in the low 60s on Thursday with breezy southwest winds and clearing skies.

KEY MESSAGE 2... An upper level trough will dive south out of Canada on Thursday and phase with the upper low over the Great Lakes Region. Another trough will race northeast from the Four Corners region on Thursday night and bring a plume of deeper moisture back towards the local area. Showers will tend to expand from west to east on Friday as a cold front wraps around the south side of the upper level low. Showers will blossom across the area, especially during the afternoon. Another dry-slot does wrap into the system on Friday evening but wrap around moisture through 700mb is forecast to return and be focused across the east half of Lake Erie on Saturday. Temperatures on Friday will be in the 50s with the highest values in the east ahead of the front. High temperatures on Saturday continue to trend downward as we end up on the back side of the upper level low. Temperatures at 850mb will be as low as -3C on Saturday morning which should be sufficient for lake enhanced rain across the east half of the forecast area. Did not add thunder but can not rule out a few isolated thunderstorms coming off Lake Erie.

Precipitation is generally expected to be done by Sunday with a gradual warming trend setting up for the early part of next week.

AVIATION /06Z Wednesday THROUGH Sunday/

VFR conditions are expected early this morning ahead of a cold front and rain entering the region from the west. A low level jet will enter the region ahead of the front and present a LLWS threat, mainly to the western TAF sites. As rain enters the region during the late morning hours, ceilings will fall to lower VFR and eventually to MVFR with persistent rain showers. Winds will remain out of the south with gusts of 20 to 30 kts with the rain today. Some IFR could develop, especially in typical spots like KMFD, KCAK, and KYNG. The cold front will move through the airspace late in the TAF period, ending the rain and shifting winds to the southwest.

Outlook...Low pressure and a cold front crossing through the region Friday into Saturday bring the next potential round of non-VFR in rain showers/low ceilings.

MARINE

Southerly winds will increase to 15-20 knots on the west half of Lake Erie today. We could see a brief window of winds in the 20-25 knot range this evening but did not issue a Small Craft Advisory given the offshore flow. Will let day shift take another look at observational data before deciding if an Advisory is needed. Southwesterly winds on Thursday may be slightly stronger and close to Small Craft Advisory criteria again. A cold front pushes south across Lake Erie on Friday with a compact trough setting up across the eastern Great Lakes. We could see a chance of both waterspouts and a few thunderstorms on Friday. A Small Craft Advisory will likely be needed for most of Lake Erie Friday night into Saturday.

CLIMATE

Daily Record High Maximum Temperatures

Date Toledo Mansfield Cleveland Akron Youngstown Erie 11-04 80(2003) 77(2015) 79(2003) 76(2015) 77(2003) 78(2015)

CLE WATCHES / WARNINGS / ADVISORIES

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