textproduct: Cleveland

WHAT HAS CHANGED

The potential for fog overnight has increased across eastern portions of the forecast area. Have added a mention of patchy dense fog to the forecast. The potential for strong southwesterly wind speeds and gusts on Wednesday has also increased.

KEY MESSAGES

1) Areas of fog, including patchy dense fog, is expected to develop overnight. Visibility may occasionally fall to one mile or less along and east of the I-71 corridor.

2) Periods of rain showers expected through the forecast period. Areawide showers accompanied by gusty winds are expected on Wednesday. Additional chances of rain/snow mix towards the end of the week.

3) Temperatures warm to above average values through the week, turning cooler towards next weekend. Extended period of above average temperatures resulting in melting of remaining snow pack and the possibility of localized ice jams on area rivers.

DISCUSSION

KEY MESSAGE 1... Light winds under building high pressure coupled with saturated low levels will lead to areas of fog, including patchy dense fog, to develop this evening through Monday morning. Latest HREF guidance shows probabilities of 1/2 mile or less visibility ranging between 40- 60% across western zones and up to 80-100% along and east of I-71. A Dense Fog Advisory may be needed for a portion of the forecast area overnight tonight.

KEY MESSAGE 2... Multiple periods of showers will continue through the forecast period. Scattered rain showers this afternoon will exit this evening as the parent low pressure drifts eastward. The next chance for rain comes Monday night into Tuesday as a weak shortwave aloft pushes across the Great Lakes region. Any slight chance to chance PoPs will be confined to Northeast Ohio and Northwest Pennsylvania. QPF will be negligible.

A more potent low pressure system will glide east across the Upper Midwest on Wednesday while lifting a warm front northeast across the local area. The low will push east into the eastern Great Lakes on Thursday before dragging a cold front east across the local area Thursday night into Friday. Precipitation ahead of the cold front will remain as all rain given the warm temperatures aloft and at the surface behind the warm front. Can't rule out a rumble of thunder and gusty showers as surface based CAPE values rise to the 400-800 J/kg range and a strong LLJ ~40-45 knots moves overhead Wednesday morning through Wednesday afternoon. Initial push of rain showers exits late Wednesday night with a dry window expected through Thursday afternoon. Chance to likely PoPs return Thursday night through the weekend. Expect p-types to be a mix of rain/snow as temperatures behind the cold front on Friday night will hover around freezing.

KEY MESSAGE 3... Upper level ridge will build across the eastern CONUS early this week. Persistent southerly to southwesterly flow will lead to 850mb temperatures rising to +5C to +8C across the region, roughly the 90th to 95th percentile when compared to climatology. A prolonged period of above average temperatures is anticipated beneath this upper level ridge. Daily highs in the low to mid 50s Monday and Tuesday will top out in the upper 50s to lower 60s by Wednesday behind a warm front. For reference, average temperatures in mid to late February are generally in the upper 30s to lower 40s.

This extended period of above normal temperatures may lead to localized impacts due to the melting of the existing snow pack and ice jams. Will continue to monitor the potential for ice jams over the next few days.

AVIATION /18Z Sunday THROUGH Friday/

A mix of low stratus and high cirrus currently and exiting light rain across the south as low pressure passes south of the region. The complication in the aviation forecast comes tonight with a low level inversion and trapped moisture, and deciphering between fog, low stratus, or nothing in the lower levels at all. Based on forecast soundings, the best chance for fog will be south and east of the MFD to CLE line, not including those terminals. Have LIFR fog in the forecast for CAK and YNG after 05Z tonight lingering into the late morning hours Monday. Going with IFR to perhaps LIFR stratus at MFD and ERI, and CLE/FDY/TOL at mainly VFR ceilings with no low stratus cloud formation expected. There is some lower confidence to this forecast at this time, with the biggest impact of this lower confidence at the VFR terminals tonight. May need to add the low stratus in if the signal for cloud cover development in the trapped inversion becomes a little more robust. For terminals that do go into low ceilings or visibilities, it will likely take some time after sunrise for the flight categories to improve.

Outlook...Non-VFR possible in rain Wednesday.

MARINE

A sliver of open water has developed just east of the islands and pulled away from the shore from around Vermilion to Cleveland. Otherwise, the lake is primarily ice-covered. Variable winds less than 10kts become offshore Monday/Monday night increasing to 10-15kts, then back to variable through Tuesday as a frontal boundary approaches and then becomes stationary near the southern shore of Lake Erie. Winds increase out of the south to 15-25kts Tuesday night, and then back to southwesterly late Wednesday into Wednesday night 15-25kts with another low pressure system moving through the region. Low pressure with a cold front is expected at the end of the week.

CLE WATCHES/WARNINGS/ADVISORIES

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