textproduct: Cleveland

WHAT HAS CHANGED

Temperatures have trended a little colder this afternoon/evening, and Friday has trended a little cooler and wetter. Otherwise, no changes to the forecast or messaging.

KEY MESSAGES

1) Unseasonably cold tonight with mid-winter like arctic air.

2) Temperatures warm to near seasonable levels Wednesday through Saturday, followed by well above normal temperatures Sunday through early next week. Periodic showers and thunderstorms are expected between Thursday and Tuesday.

DISCUSSION

KEY MESSAGE 1... An amplified pattern continues this afternoon characterized by deep mid/upper troughing over the Great Lakes and Northeast CONUS downstream of broad mid/upper ridging over the western U.S. and Plains. This is maintaining a northwesterly feed of arctic air through the region, but strong surface high pressure building in from the central Great Lakes has allowed skies to clear out, so the strong April sun at least makes it feel slightly better. Lowered highs a couple of degrees this afternoon based on current observations. Lingering lake-effect clouds in far NE Ohio and NW PA will clear out by early evening as the high builds overhead, and this will set up strong radiational cooling tonight. Expect lows to bottom out in the low/mid 20s areawide, with teens in favored portions of interior NE Ohio and NW PA and perhaps along the U.S. 30 corridor.

KEY MESSAGE 2... Quiet weather and welcomed warming will begin Wednesday as the mid/upper trough lifts out and allows for height rises across the region as the surface high shifts into New England and also sets up return flow. The warming trend will continue Wednesday night and Thursday as a warm front lifts across the region ahead of a mid/upper shortwave and associated surface low progressing into the northern Great Lakes. The low-level moisture return in the warm sector ahead of this system does not look too impressive, partly due to the strongest upper support passing north of the region leading to a weaker low-level jet response. However, some pooling and low-level convergence ahead of the trailing cold front will generate scattered showers and thunderstorms late Thursday and Thursday night as the front gradually sags into the region from NW to SE, so POPS have trended a little faster on Thursday. Any convection Thursday afternoon and Thursday night should be mostly low-impact.

The period to watch for somewhat more impactful weather will be Friday and Friday night as the front becomes quasi-stationary across the region in response to a mid/upper jet max forming a surface wave on the front. Details are still uncertain, but as the wave tracks along the boundary during the day Friday, slightly higher wind fields and associated shear, along with better low-level moisture advection, could generate a few stronger thunderstorms as well as locally heavy rain. Given how saturated the soils are in many areas, this could cause localized impacts, so trends will be monitored.

The front will be pushed into the Ohio Valley Saturday as Canadian high pressure at the surface builds across the Great Lakes, setting up dry and cooler conditions. This front will quickly return north as a warm front Sunday as a broad area of deep southerly flow develops through early next week along with corresponding mid/upper ridging building into the eastern CONUS. This is in response to a strong mid/upper trough and closed low slowly progressing from the Pacific Northwest Sunday into the Plains by Tuesday. In this pattern, confidence is highest that temperatures will warm to well above normal levels Sunday through Tuesday. Shower and thunderstorm chances are less certain. A series of shortwaves will eject out of the main upstream upper trough/low and traverse an active baroclinic zone/quasi-stationary front across the Great Lakes. This will bring periodic clusters of convection, but the placement of the boundary may keep the bulk of it north of our area until the front starts to sag into the region Tuesday. At this point, expect periodic showers and thunderstorms (mostly scattered) between Sunday and Monday, with a more organized round possible Tuesday. The timeframe around Tuesday will be the next period to watch for potential severe weather and heavy rainfall.

AVIATION /18Z Tuesday THROUGH Sunday/

The main message for aviation weather with this midday 18z TAF update will be VFR conditions are expected this afternoon through tonight and Wednesday. The are some lingering scattered to broken lake effect ceilings over far NEOH and NWPA around the YNG and ERI site around 3500 feet this afternoon. These clouds will gradually scattered out later this afternoon and early evening. Elsewhere, skies are mostly clear this afternoon and these fair weather conditions will stay through the end of this TAF period or early afternoon Wednesday. High pressure is building in this afternoon. Winds will start out from the north or northeast 5 to 10 knots this afternoon. Winds will decrease down to around 5 knots tonight and become easterly overnight. Winds will shift back around from the southeast by Wednesday morning around 10 knots.

Outlook...Non-VFR possible in scattered rain showers on Thursday night through Friday.

MARINE

Conditions on Lake Erie will continue to calm down as high pressure builds into the region this afternoon and evening. Winds this afternoon will be from the north or northeast 5 to 12 knots. Waves are still gradually decreasing and will be around 2 to 4 feet this afternoon as the lake continues to settle down. Winds will shift around from the east tonight and southeast on Wednesday increasing to 8 to 15 knots. The next cold front will approach Lake Erie late Thursday. Southerly winds will increase Wednesday night 15 to 20 knots. Winds will become southwesterly on Thursday between 15 and 20 knots. Even though the wind will be mainly an offshore flow late Wednesday night into Thursday, we may need additional Small Craft Advisories if the trends for wind speeds increase closer to 25 knots. That cold front may weaken as it moves across Lake Erie Thursday night with decreasing and variable winds overnight. Winds will remain southwesterly on Friday 10 to 15 knots before another front moves across Lake Erie with a shift from the north 5 to 10 knots by Friday night. High pressure will be near the lake this weekend with a light northeasterly to easterly flow expected on Saturday. A return flow of southerly winds will be back by Sunday, increasing late in the day 8 to 15 knots.

CLE WATCHES/WARNINGS/ADVISORIES

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