textproduct: Cleveland

WHAT HAS CHANGED

Increased rain chances before sunrise this morning near the lakeshore, and slightly increased rain chances tonight into Friday afternoon. Also increased winds on Lake Erie this morning through Friday.

KEY MESSAGES

1) Light rain lingers near the lakeshore early this morning, then very warm today followed by a soaking rain tonight into Friday.

2) Cool and dry weather this weekend through mid next week. Frost headlines are possible Monday night and Tuesday night.

DISCUSSION

KEY MESSAGE 1... Rain showers overperformed this past evening and early this morning in a zone of broad warm air advection and isentropic ascent along and north of a warm front. This band of light rain is gradually lifting north with the frontal boundary, but increased POPS along the lakeshore of northern Ohio and NW PA through 14Z this morning to reflect a slower exit. Additional QPF will only be a trace to few hundredths of an inch.

By mid morning, any remaining showers will exit NW PA as the area becomes firmly in the warm sector. A tightening pressure gradient between surface high pressure over the Mid Atlantic region and a cold front approaching from the western Great Lakes will lead to gusty SSW winds over 20 knots at times, and this combined with 850 mb temps rising to 17-18 C will boost highs into the low 80s this afternoon. The aforementioned cold front is associated with a deepening mid/upper trough over the northern Plains and northern/central Great Lakes, leading to strong height falls over the southern Great Lakes and Ohio Valley by tonight. This trough still looks to absorb the old cut off low that impacted the Desert Southwest earlier in the week, but the jet support and resultant surface wave on the frontal boundary is trending weaker. This will result in more of a frontal passage rain event tonight as opposed to a surface wave riding along the boundary, so QPF is trending lighter. Nevertheless, the front will be slow to cross the region given the strength of the ridge at the surface and aloft over the Mid Atlantic and SE CONUS, so expect the band of rain showers to last from tonight into Friday afternoon, only slowly ending from NW to SE. The right entrance of a modest 80+ knot H3 jet rounding the base of the trough also supports enough dynamics/frontogenesis for widespread rain showers tonight into Friday, so slightly increased POPS from 23Z this evening through 18Z Friday as the rain slowly sinks NW to SE. Minor instability this evening could cause isolated thunder, but this will largely be stratiform rain. Overall, looking at 0.40 to 0.80 inches of QPF across the region, with the highest amounts in NW Ohio and near the lakeshore.

Drier air will quickly work into the region Friday evening and Friday night, but it will be the start of a much cooler pattern as the elongated mid/upper trough takes up residence from the northern Plains through the Great Lakes and Northeast CONUS, and a strong Canadian high at the surface builds down across the Great Lakes. This will lead to a chilly night Friday night, with lows dipping into the low/mid 40s.

KEY MESSAGE 2... The mid/upper trough and Canadian high will remain across the Great Lakes Saturday before another reinforcing shortwave and associated surface low tracking near Hudson Bay brings another cold front through the region Sunday, effectively reloading the trough and allowing an even more impressive 1025-1030 mb surface high to build down from the Upper Midwest early next week. This will keep cool and dry conditions in place, with temperatures eventually averaging 10 degrees below normal Monday and Tuesday. Expect highs in the mid 60s Saturday to slightly rebound into the upper 60s to near 70 Sunday before dropping into the upper 50s/low 60s Monday and Tuesday. Lows in the mid 30s to low 40s Monday night and Tuesday night could support the first frost of the season in portions of interior north central and NE Ohio and NW PA. Gradual moderation is expected by Wednesday.

AVIATION /12Z Thursday THROUGH Monday/

The main message for aviation weather today is VFR conditions are expected to continue today into this evening with high and mid level clouds above 6000 feet through this evening. A cold front with widespread rain showers will move in late tonight through the end of this TAF period or 12z Friday morning. There will be gradual lowering of ceilings after 03z this evening for NWOH and later in time after 06z tonight NEOH and NWPA. Forecast confidence is lower end MVFR is expected but there may be lower into IFR towards towards the very end of the TAF period or closer to the 09z to 12z Friday timeframe. Rain showers will also reduce visibility 3sm to 5sm during the late night hours. Winds will be southerly to southwesterly 8 to 13 knots later today with afternoon gusts up to 20 knots ahead of the approaching cold front through 00z. The winds will shift out of the west to northwest late in the night around 10 knots late tonight towards 12z Friday morning.

Outlook...Non-VFR likely with rain showers and lower ceilings behind a cold front late Thursday night through late Friday morning.

MARINE

SSW winds will increase on Lake Erie behind a warm front this morning, with speeds of 10-15 knots through the day. These winds will quickly turn N and briefly reach 15-25 knots late tonight behind a strong cold front, so issued a short-fused Small Craft Advisory from 03-14Z Friday from the Islands to Conneaut where criteria is most likely to be reached (winds and 3-5 foot waves), but it will be choppy everywhere. N winds briefly decrease to 10-15 knots Friday morning through the afternoon before briefly nearing 20 knots again Friday evening, so another headline may be needed Friday evening into early Friday night.

NE winds will average 5-15 knots by Saturday as high pressure builds across the Great Lakes before turning S at 5-10 knots early Sunday ahead of another cold front. Winds then turn W and eventually NW behind the front late Sunday and increase to at least 15-20 knots Sunday night into Monday, so another period of Small Craft headlines will be possible. Getting to be that time of year!

CLE WATCHES/WARNINGS/ADVISORIES

OH...None. PA...None. MARINE...Small Craft Advisory from 11 PM this evening to 10 AM EDT Friday for LEZ144>148.