textproduct: Cleveland

WHAT HAS CHANGED

A High Wind Warning has been issued for Erie County Pennsylvania and the Wind Advisory has been expanded to Summit, Portage, and Trumbull counties. Northwest Ohio has been lowered from a Slight Risk to a Marginal Risk of severe thunderstorms for late tonight. Raised pops outside of the snowbelt on Monday night where a light coating of snow is possible.

KEY MESSAGES

1) Windy conditions return today, with a Wind Advisory in effect for much of the area and a High Wind Warning in effect for Erie County Pennsylvania. Damaging winds will also be possible late tonight in Northwest and North Central Ohio as showers and possibly a few thunderstorms bring strong winds along a cold front.

2) Wintry weather returns Monday night and Tuesday with wind chills dropping into the single digits. Accumulating snow is likely in the primary snowbelt region, with scattered snow showers elsewhere.

DISCUSSION

KEY MESSAGE 1...

A dynamic system will impact the region over the next 24 hours as an upper level trough deepens across the Mid-Mississippi Valley today then becomes negatively tilted overnight with a closed low lifting north across Lake Michigan. Surface low pressure is located over Kansas and is forecast to lift a warm front north across the area this morning as it tracks northeast towards Chicago. The local area will undergo rapid warming today with much of Ohio reaching the upper 60s to near 70 in the west, while the warm front is slow to pass Northwest Pennsylvania where temperatures top out in the upper 50s.

High winds remain the primary concern today as a strong wind field arrives this afternoon. A low level jet with speeds of 60-70 knots will pass over Northwest Ohio. As mixing heights increase today, areas in the Wind Advisory will see wind gusts increase to 50 mph or greater. The extent of mixing is a concern, especially in NW Ohio where mixing heights could be near 5k feet and could possibly tap into some of the higher gusts. The placement in the warm sector today does not provide any downward momentum transfer and HREF probabilities of exceeding 60 mph wind gusts are quite low through the afternoon. While an upgrade to a High Wind Warning in NW Ohio can not be ruled out, the greatest likelihood is for winds to remain more in the Advisory range.

For tonight, downsloping winds will continue to strengthen in Erie County Pennsylvania. The southeasterly wind direction is favorable with a tightening gradient and wind speeds at 925mb increasing to around 65 knots. This tends to be an effective set-up to mix the stronger wind gusts down to the surface and the High Wind Watch has been upgraded to a High Wind Warning. The strongest winds are expected between 8 PM and 2 am along the Erie lakeshore with several hours of Advisory level winds on either side.

The next concern is the arrival of the cold front wrapping in from the southwest as the system occludes overnight. The Storm Prediction Center has backed off slightly on the convective risk, removing most of the Slight Risk area from Northwest Ohio with a Marginal Risk for severe thunderstorms from the I-75 corridor to just west of I-77. Instability is a limiting factor for thunderstorms tonight but the concern remains for damaging winds with showers along the cold front. The wind field will be very strong when the front arrives, with speeds at 850mb of 60-70 knots. The strongest winds are oriented at a 30-40 degree angle to the front initially which is less favorable than if the winds were perpendicular. As the front moves eastward, they are expected to become increasingly more parallel to the front and that may help to reduce forward motion with decreasing intensity towards sunrise. Trends will be monitored this evening as this line of showers approaches and severe weather warnings are still possible overnight. The greatest threat is wind gusts to 70 mph between the hours of 2 AM and 6 AM.

KEY MESSAGE 2...

A return to winter-like conditions will occur behind the strong cold front as temperatures fall throughout the day on Monday and are largely in the mid to upper 20s on Tuesday. Temperatures at 850mb fall by about 25C from 06Z Mon to 06Z Tues. The effects of the cold will be amplified by the windy conditions as we reside on the southern side of a broad trough remaining across the eastern Great Lakes. Wind chill values are forecast to be in the single digits Monday night into Tuesday morning with winds gusting to 25 mph. Precipitation type will transition back to all snow by Monday evening and the upper level trough axis pivots through Monday night bringing scattered snow showers to much of northern Ohio. Precipitation amounts are expected to be light and road temperatures may still be marginally warm from Sunday, but a light coating of snow is possible and could result in slick conditions as temperatures continue to fall. Most of northern Ohio will only see about a half inch of snow but additional accumulations will be possible in the snowbelt heading into Tuesday.

A uni-directional west southwest flow will be in place across Lake Erie on Monday night. Lake to 850mb delta T increases to about 20C with moderate instability for lake enhanced snows. We do start to lose moisture on Tuesday both above 700mb and with dewpoints falling into the single digits upstream of Lake Erie. Snow showers are expected across much of the snowbelt, shifting slightly inland Tuesday morning, then shifting back closer to the lake Tuesday evening as the surface ridge builds in from the southwest. Light accumulation of generally 1-4 inches are expected across the snowbelt with the higher amounts possible where westerly bands set-up. We will need to monitor intensity of snow bands for any locally higher amounts and continue to refine the snowfall forecast as mesoscale details such as wind direction/moisture depth come into better agreement.

Fortunately the cold does not stick around very long with upper level ridging extending into the Upper Ohio Valley towards the weekend. Normal highs are in the mid to upper 40s for mid March and we expect to see most of the area in the 50s by Friday.

AVIATION /18Z Sunday THROUGH Friday/

The main impactful weather concern for aviation and this TAF update will be the strong and very gusty winds during the entire time period. Winds from the south have ramped up 15 to 25 knots this afternoon with like gusts 35 to 45 knots, especially areas of northwest and north central Ohio. Conditions will remain VFR this afternoon into the late evening. Clouds will increase from west to east this evening and eventually MVFR ceilings will move in later tonight through the rest of the time period or 18z Monday. There will be a strong cold front that will sweep across the area late tonight into early Monday morning. There will also be a line or area of showers with isolated thunder possible associated with the frontal passage. This is mentioned with TEMPO groups from west to east late tonight/early Monday morning. A brief period of lower MVFR ceilings and visibility due to heavier showers will likely impact all TAF sites. At this time, we have only mentioned the potential for -TSRA at FDY and TOL but that may need to be added to TAFs further east with future updates. Ceilings will stay MVFR to low end MVFR on Monday.

The stronger winds this afternoon will decrease a little overnight but still remain in the 15 to 25 knot range and gusts to 35 knots tonight and Monday. Winds will also shift from southerly to southwesterly by Monday morning.

Outlook...Non-VFR will likely persist with scattered rain showers changing to scattered snow showers on Monday. Lake effect snow showers and possible squalls will impact the Snowbelt of NEOH and NWPA Monday night into Tuesday.

MARINE

Marine weather conditions are expected to be very rough today through Tuesday. A Small Craft Advisory is currently in effect today into tonight. A Gale Warning will take in effect for all of Lake Erie Monday morning through Tuesday morning. Southerly winds will increase 25 to 30 knots today and tonight. Southwester to westerly Gales 35 to 40 knots will move over Lake Erie Monday through Tuesday morning. Gusts Monday will be up to 50 knots likely. Waves will be increase with the highest over the open basin up to 15 feet or more. Winds will slowly ease down Tuesday into Tuesday night but remain from the west 15 to 25 knots. Additional SCA will likely be needed after the Gale Warning. Winds and waves will be on the lighter side mid to end of next week, southerly around 10 knots

As the strong winds shift southwesterly to westerly behind the strong cold front Monday morning, water levels will likely drop in the western basin of Lake Erie. A Low Water Advisory has been issued Monday morning through Tuesday morning as water levels are expected to drop below the critical mark for safe marine navigation.

CLE WATCHES/WARNINGS/ADVISORIES

OH...Wind Advisory until 8 AM EDT Monday for OHZ003-006>014-017>023- 027>031-036-037-047-089. PA...Wind Advisory until 8 AM EDT Monday for PAZ003. High Wind Warning until 8 AM EDT Monday for PAZ001-002. MARINE...Small Craft Advisory until 8 AM EDT Monday for LEZ142>149. Gale Watch from Monday morning through Tuesday morning for LEZ142>149-162>169. Low Water Advisory from 8 AM Monday to 8 AM EDT Tuesday for LEZ142>144-162>164.