textproduct: Cleveland

WHAT HAS CHANGED

Added some timing resolution to POPs on Tuesday, showing a period of relatively drier weather during the day before convection moves in from the northwest late Tuesday and Tuesday night. Confidence in us surging well into the warm sector on Thursday is increasing, with warmer temperatures and a window of drier weather that day.

KEY MESSAGES

1) Hit and miss shower and thunder chances at times through early Tuesday, followed by greater potential for showers and thunderstorms late Tuesday into early Wednesday with a cold front. Some storms late Tuesday into Tuesday night may be severe.

2) The next system in our active pattern is expected Thursday and Friday, with returning shower and storm chances and another brief surge of warmer and more humid conditions.

3) Unsettled weather continues this weekend as low pressure lifts through the Great Lakes, bringing more fronts across the local area.

DISCUSSION

KEY MESSAGE #1:

Most of the day Monday will be dry but with a fair amount of cloud cover driven by ongoing low-level warm air/moisture advection. Highs will push well into the 60s with some western sites likely touching 70. There will be enough of a low-level jet to yield modestly gusty surface winds as mixing deepens this afternoon and early evening, especially along/west of I-71 where peak gusts may reach 30 MPH.

A flat/low-amplitude shortwave will zip across the central Great Lakes this evening and tonight as elevated instability advects in aloft. The combination of modest lift and increased moisture along and ahead of the shortwave to go along with developing elevated instability will lead to an increase in shower and thunderstorm chances beginning late afternoon/early evening, with activity likely peaking this evening and tonight. Activity should diminish and/or shift farther northeast late tonight into Tuesday morning as a capped warm sector becomes established across the area. The greatest rain potential late today and tonight will stretch from the Toledo area east-southeast across Lake Erie into Northeast OH and Northwest PA, with relatively lower POPs and QPF amounts farther south and southwest. Some hi-res models suggest localized corridors of over 1.50" of rain may occur with more organized convection through early Tuesday across some of our northern and northeastern counties, though that will largely be the exception with area average QPF more likely to land in the 0.40-1.00" range across extreme Northeast OH and Northwest PA in that timeframe, diminishing farther southwest. Given this, not expecting notable flooding concerns through Tuesday morning. As a decent elevated mixed layer (EML) works in overnight tonight, bringing steeper mid-level lapse rates amid moderate deep- layer shear, do not want to rule out a bit of hail with any elevated convection. However, the overall severe weather risk will be minimal tonight. Lows tonight will be mild, ranging from the mid- upper 50s east to lower 60s west.

Once lingering showers/storms exit northeast Tuesday morning, most of the day will be dry, breezy, and quite warm. Capping and a lack of forcing in the open warm sector should lead to mainly dry weather until convection potential along the approaching cold front works in from the northwest late Tuesday or Tuesday evening. Highs on Tuesday will push well into the mid-upper 70s for most, with a few sites quite possibly touching 80 in we see enough sunshine and a long enough window of rain-free conditions. Wind gusts of 30-40 MPH are likely on Tuesday in a warm/mixed airmass beneath a moderate low- level jet, with a few gusts to 45 MPH possible west of the I-71 corridor in the afternoon and early evening.

Shower and storm potential increases from the northwest late Tuesday into Tuesday night as large-scale forcing increases and a cold front sags in. There is some disagreement over how quickly the cold front and convective potential with it sinks into our area, with some guidance suggesting this happens as early as late Tuesday afternoon across Northwest OH while a majority of guidance suggests Tuesday evening/night is more likely. Through the evening hours, a combination of increasing forcing, moderate to strong low-mid level flow and weakly capped or uncapped instability can support organized surface-based convection along or just ahead of the front. Thereafter, the low-levels appear to stabilize enough to minimize severe potential overnight Tuesday night. If surface-based convection is realized, 40-50kt of effective deep-layer shear, including strong 0-3km shear of over 40kt, along with weak to moderate instability (up to 1500 J/KG of MLCAPE) and steep mid-level lapse rates (up to 7.5C/km) can support all modes of severe weather, with damaging winds the most likely hazard followed by large hail and perhaps a couple of tornadoes. However, uncertainty remains over how quickly the front can push in before the environment becomes less supportive of severe weather. Overall, the greatest potential for severe weather is in the Toledo area with gradually diminishing potential farther southeast. The new SPC Day 2 Outlook has a Slight Risk (level 2/5) across the northern third of our area, diminishing to a Marginal Risk (level 1/5) farther south. Don't feel this is unreasonable, though the confidence in the Slight Risk is higher farther northwest with a weakening trend likely southeast across our forecast area.

Rain and some elevated convection are expected to spread south- southeast across the rest of the area later Tuesday night into Wednesday along and behind the frontal passage. Area average rain amounts of 0.60-1.20" are forecast across the northern half of our area late Tuesday into Wednesday, diminishing to the south. Locally up to 2.00" may occur with especially organized or training convection. This round of rain will likely cause area streams/creeks/rivers to rise more sharply, with a few more prone points possibly reaching minor flood...though overall, widespread flooding is not expected.

A brief period of drier weather is possible behind the front later Wednesday morning and afternoon ahead of the next system. A notable airmass change is likely behind the front, with forecast highs on Wednesday ranging from the 40s near Lake Erie to perhaps the lower 60s well inland. There is some uncertainty regarding if our southern counties are still rather mild Wednesday morning, though it should be noticeably cooler than Tuesday overall at the end of the day.

KEY MESSAGE #2:

The next trough starts digging into the Plains quickly Wednesday and Wednesday night, causing heights to rise locally and sending our prior cold front back northeast as a warm front late Wednesday and Wednesday night. Another round of showers and some elevated convection will occur along and ahead of the warm front late Wednesday into Wednesday night.

The trough to our west takes on a negative tilt and lifts northeast into the upper Great Lakes Thursday into Thursday night, pulling a deepening low pressure across the central Great Lakes. Thursday is looking more likely to be a drier and very warm day as we get well into the warm sector. Some POPs linger on Thursday, especially across Lake Erie and Northeast OH/Northwest PA early in the day, and then increasing from the west-northwest ahead of the approaching cold front late in the day. However, there should be some dry breaks with highs surging well into the 70s...with lower 80s possible if we end up seeing enough dry time and sunshine.

Rain potential should increase from the west-northwest late Thursday and Thursday night as the low passes to our north and drags the cold front into the local area. This cold front has trended slower in recent runs of guidance, leading to forecast highs for Friday trending a bit warmer as POPs also trend higher. POPs will need to remain fairly high on Friday until the front can clear.

Overall, this system isn't particularly alarming from a severe weather or heavy rain/flooding perspective. However, there may be enough rain area-wide to keep rivers a bit elevated.

KEY MESSAGE #3:

Any period of drier weather behind the Thursday-Friday system won't last too long, as models agree on a fairly impressive trough ejecting into the Plains Friday night and Saturday and shifting into the upper Great Lakes on Sunday. This will drive yet another low pressure towards the upper Great Lakes Saturday into Sunday. This low looks to lift our front back north as a warm front Friday night into Saturday, followed by another cold frontal passage Saturday night or Sunday. Rain amounts and severe potential will depend on the exact track and strength of the low, along with the timing of the cold front. Given that, it's too early to speculate on potential hazards with the weekend system. However, it's safe to say our unsettled/active pattern from this week will continue through the weekend.

AVIATION /12Z Monday THROUGH Friday/

A mid-level, VFR cloud deck continues across the region this morning, although the ceiling flavor is trending more broken than overcast, especially near Lake Erie. Winds will increase over the next hour or two, ending the LLWS threat this morning. With increasing moisture into the region, ceilings should fall a bit this afternoon to 3-5 kft for most of the terminals. Some rain will enter from the northwest, moving along the warm front. The rain will impact the northeast terminals the most with some MVFR ceilings and visibility. There is a bit more confidence in some TS into KERI tonight and have introduced a brief VCTS period. Rain should exit after midnight but MVFR ceilings will continue to spread south through the terminals. A strong low level jet will return tonight and allow for LLWS conditions to also return for most terminals. During the daytime on Tuesday, conditions should trend back to VFR across the area and mixing should end the LLWS threat but wind gusts at the terminals may end up in the 25-35 kt range.

Outlook...Non-VFR likely in showers and thunderstorms Tuesday night into Wednesday. Additional periods of non-VFR conditions possible in rain on Thursday and Friday.

MARINE

Offshore flow will be favored through Tuesday evening with a warm front crossing the lake and southwest return flow surging across the region. Winds may be a bit more muted during the daytime hours today as the front lifts over the lake. Tonight, expecting winds in the 15 to 20 kt range as a low level jet enters the region, along with some shower and storm activity. Tuesday should be an efficient mixing day and winds should at least stay in the 15 to 20 kt range but could even accelerate further to 25 kts. A small craft advisory remains possible tonight into Tuesday with the enhanced southwest flow.

For Tuesday night into Wednesday, a cold front will cross the lake and northwest flow will return to the basin. Winds with the cold advection do not appear all that strong on Wednesday and any increased wave activity may be brief late Tuesday night. This cold front will hover over the area on Wednesday and lift north on Thursday. This will allow for easterly flow on Wednesday night and offshore southerly flow to return on Thursday. The Thursday warm sector appears efficient again and 15 to 20 kts of offshore flow seems likely at this time. A cold front will move through on Friday and winds will shift to the northwest and weaken.

CLE WATCHES/WARNINGS/ADVISORIES

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