textproduct: Cleveland

WHAT HAS CHANGED

Slightly increased chances for rain this morning through the afternoon today as a weak trough crosses the region. The chance of freezing rain has diminished. Rain chances were also increased areawide Friday as the stronger low drops through the eastern Great Lakes, but the greatest coverage of rain still looks to be across NE Ohio and NW PA.

KEY MESSAGES

1) Scattered, light rain showers are expected this morning into the early afternoon. Amounts will be light and low-impact and mainly confined to NW and north central Ohio.

2) Warmer Friday through the weekend with two systems impacting the region. The first Friday will bring a more widespread rain and a few potential thunderstorms. The second Sunday will bring another round of showers and thunderstorms then much colder air early next week. No severe weather expected at this time.

DISCUSSION

KEY MESSAGE #1... Early morning infrared satellite and water vapor loops show the amplified pattern continuing across the Lower 48 characterized by a strong mid/upper ridge over the western CONUS and southern Plains and broad mid/upper trough over the eastern CONUS. A weak shortwave analyzed over the western Great Lakes is generating scattered precip across Lower Michigan and Indiana near the left exit of a 120+ knot H3 jet streak. This weak shortwave will continue southeastward through the southern Great Lakes and Ohio Valley today, with the associated weak surface trough/cold front crossing the region this morning. Slightly raised POPS for scattered rain showers this morning through early afternoon. Moisture is limited with a lot of dry air in place, but the aforementioned trough moving through combined with the upper jet streak forcing should allow for decent coverage of light showers this morning, lingering into the early afternoon before exiting to the southeast. Any rainfall amounts will be light (0.05 inch or less), and the greatest potential for measurable rain will be in NW and north central Ohio closer to the upper jet support. Removed the mention of freezing rain this morning since surface temperatures are currently in the mid 30s in most areas and should not fall much more before any precip begins. KEY MESSAGE #2... A stronger northern stream mid/upper shortwave is still on track to drop through the broad trough Friday. The associated clipper low pressure system will track from Lake Superior Friday morning across the eastern Lake Ontario region by late afternoon. The associated H3 jet streak (120+ knots) will be in much closer proximity with this system Friday morning, with the left exit region providing abundant lift over the southern Great Lakes region. This combined with a 40-50 knot westerly low- level jet in response to the upper forcing will generate a larger shield of rain showers, with the main swath of measurable rain tracking through NE Ohio and NW PA Friday morning through early afternoon where the low-level jet will focus warm/moist advection and isentropic ascent ahead of the warm front. Raised POPS everywhere Friday morning into the afternoon, with the highest POPS in the NE counties.

Much warmer temperatures in the warm sector Friday afternoon will briefly allow for some weak instability on the far southwest edge of the steadier rain shield before the trailing cold front crosses the region. This part of the forecast is lower confidence since the front looks to cross quickly in the mid to late afternoon, which could quickly pinch off the instability. HREF probabilities for >250 joules of SBCAPE are highest along a roughly Marion to Mt. Vernon line but still only in the 20-40% range, so the best chance for convection and associated thunder/lightning will be in our SW counties. Severe weather is generally not expected, but cannot rule out small hail if any convection materializes given cooling temps aloft.

High pressure will briefly build in Saturday with slightly cooler temps, especially near Lake Erie given onshore flow, but temps will still be above normal. Warm air advection will quickly bring the warmer air back Sunday as the front returns north as a warm front ahead of another northern stream mid/upper shortwave dropping into the Upper Midwest and Great Lakes. This will start to deepen the longwave trough over the Great Lakes again, with an associated surface low tracking across Lower Michigan Sunday and dragging a strong cold front across the region in the afternoon and evening. Guidance continues to suggest a decent surge of warmth and moisture ahead of this front, and there will be some strong dynamics and associated shear in place ahead of the deepening trough. At this point, the best overlap of shear and instability still looks to be over the Lower Ohio Valley, but will need to watch for some stronger convection if the better instability can trend northward, especially since we will have a favorable late afternoon/evening cold frontal passage. Much colder air and below normal temperatures will return early next week as the troughing becomes reestablished across the Great Lakes and Northeast.

AVIATION /12Z Thursday THROUGH Monday/

Scattered light rain this morning in TEMPO groups with brief MVFR ceilings possible due to a weak upper level disturbance. Otherwise, VFR with wind direction changes through the period under 10kts as high pressure moves in temporarily today followed by a warm front tonight.

Outlook...Non-VFR possible in rain showers and low ceilings Friday and Sunday with cold fronts.

MARINE

Winds variable today and tonight with high pressure moving in, becoming southwesterly Friday 15-20kts and wave heights 1-3ft east of Cleveland. A late Friday cold front turns winds northwesterly 10kts and wave heights building to 1-3ft for all nearshore zones before becoming light and variable Saturday and wave heights falling below 2ft. Offshore winds 10-15kts early Sunday before a strong cold front moves through Sunday afternoon. Northerly onshore winds 20- 30kts behind the cold front into Sunday night with Small Craft Advisories likely to be needed.

CLE WATCHES/WARNINGS/ADVISORIES

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