Marine Weather and Tide Forecast for Leesville, OH

NEAR TERM /UNTIL 6 AM THIS MORNING/
KEY MESSAGES:

- Cold Weather Advisory/Extreme Cold Warning in effect

-----------------------------------------------------------------

Update...
Nudged temperatures down further with most locations in the single digits, and a few observations coming in just below zero outside of the higher terrain. The 00Z sounding shows dry air in place, and this will continue to support clear skies much of the night. No other changes for the late evening update.

Previous discussion...
The latest surface analysis shows a ridge of surface high pressure across the Upper Ohio Valley region. Skies have cleared under this ridge, and temperatures have been running colder than guidance so far this evening. Lowered overnight lows based on the expected clear skies, diminishing wind, and snow pack in place. Some increase in mid level clouds is expected late tonight, though this should have minimal impact on overnight lows. Currently forecasting for all areas to drop below zero overnight, with wind chills across the lower elevations around -15. Wind chills across the ridges are expected to be as low as minus 25.

SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/
KEY MESSAGES:

- Arctic outbreak with dangerously cold temperatures and wind chills.
- Extreme Cold Warning for ridges and Advisory for lowlands in effect.
- A passing shortwave could impact the Tues afternoon/evening commute

--------------------------------------------------------------------

EXTREME COLD THROUGH WEDNESDAY MORNING...

Confidence is high that a potentially dangerous cold weather outbreak is expected to continue into the short term period as an arctic airmass lingers across the Great Lakes/Ohio River Valley region.

Long and short range models (NAEFS and GEFS) have climatological anomalies ranging within the -3.5C to -4.0C standard deviation for the upper-lvl temps (850mb/700mb/500mb) and highlighting that return interval of this cold outbreak is a 1 in every 10 year occurrence, which is rare. The coldest time period is expected to be late Tuesday into Wednesday morning as an embedded shortwave tracks through the Dakotas and advances the coldest air aloft, which is currently in the Midwest, towards the East Coast. Record lows and record LoMax temps could be tied or broken at a number of climate sites tomorrow into Wednesday.

The potential for upgrading to a Extreme Cold Warning across the region is below 50% for early Wednesday. The spread of the apparent temperatures for the latest run of the ensembles that cover the 25th to 75th percentile is 6 degrees (between -17F to -23F). A potential outcome is that a strong sfc high builds over the region (potentially as high as 1040mb) and measured temps could range from -15F to -18F but with very little wind.

Historically, these are the noted impacts across our region with a cold weather outbreak this severe: Unprotected pipes can freeze and burst. Prolonged exposure to the cold may lead to hypothermia. Frostbite can occur in as little as 30 minutes for exposed skin.

We advise checking in routinely with vulnerable friends and family. Extreme care is encouraged for the protection of pets and animals. Rescheduling any events, especially those taking place outdoors, is also encouraged.

Along with cold weather, a potential shortwave is expected to cross the region Tuesday afternoon and increase the threat of hazardous travel due to snow. Snowfall amounts are expected to stay below Advisory criteria (likely 0.5 to 1.0 inches in isolated areas; a trace to 0.5 elsewhere). However, brief periods of low visibility from heavy snow can't be ruled out.
The 0-3km CAPE values range from 25J/kg to 50J/kg along the trough axis. Hi-Res guidance also has some noted potential stronger bands (reflectivity on the radar could measure 20DBZ to 30DBZ at times) between 3pm to 6pm (including Pittsburgh). If models remain consistent with this potential outcome, short- fused special weather statements and/or snow squall warnings may be needed to highlight the threat.

LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/
KEY MESSAGES:

- Confidence is high that very extremely cold temperatures will exit the region Wednesday. However, below average temps are expected to linger.
- Near normal temps and widespread precip may return Sunday into Monday

--------------------------------------------------------------------

A ridge axis is expected to drift over the Ohio River Valley early Wednesday. The return of warm southwest flow will likely end the threat for extreme cold conditions across portions of the region by mid-day. Overnight lows/wind chills late Wednesday into early Thursday may prompt a Cold Weather Advisory for forecast zones within the ridges (Tucker/Preston), but the potential of -10F wind chill values for the lower terrain is low (less than 10% based on numerous long range ensembles).

Models have been consistent that widespread precipitation may return on Sunday. Probability of measurable precipitation within a 24 hour time period is 60% to 75%, higher values noted along the ridges. If temperatures trend colder, there is a 10% chance of snow amounts along the ridges reach or exceeding the Winter Weather Advisory criteria. If warm air lingers, snow ratios could trend down (decreasing snow amounts totals) and a rain/snow/wintry mix may occur in portions of our region.

AVIATION /06Z TUESDAY THROUGH SATURDAY/
Light wind and VFR conditions continue and are expected to last into the day Tuesday. The end of this will be brought about as an upper- level shortwave slides through the region later in the day Tuesday.
This shortwave is expected to result in borderline MVFR/VFR cigs (60- 80% probability). There also will be the chance for isolated snow showers. VIS in these showers can briefly reduce to 1 mile or less.

Outlook...
Development of strong surface high pressure from the west will return VFR (near 100% probability) to all sites by Wednesday.
Restriction and precipitation chances increase Friday with the likely approach/passage of the next upper level trough.

CLIMATE
A period of anomalously cold weather is expected to settle in through Wednesday that will challenge many standing January temperature records. Attached below are the standing climatology for local sites. Pittsburgh has a full record, while other sites are partial records and may not be fully reflective of historical temperatures:

January 21st: High Minimum Low Minimum Pittsburgh, PA 5F (1984) -18F (1985)
Wheeling, WV 12F (2000) -2F (1924)
Morgantown, WV 2F (1985) -18F (1985)
New Philadelphia, OH -8F (1985) -19F (1985)
Zanesville, OH 7F (1985) -22F (1984)
DuBois, PA 0F (1985) -22F (1985)

January 22nd: High Minimum Low Minimum Pittsburgh, PA 10F (1961) -14F (1936)
Wheeling, WV 11F (2014) -4F (2014)
Morgantown, WV 11F (2014) -5F (1984)
New Philadelphia, OH 5F (1984) -15F (1994)
Zanesville, OH 13F (2014) -11F (2011)
DuBois, PA 8F (2013) -11F (1984)

Below is the lowest daily high and daily low temperatures of the 21st century. This encompasses all days of all months running from January 2000 to present:

High Minimum Low Minimum Pittsburgh, PA 4F (01/07/2014) -10F (01/17/2009)
(02/20/2015)

Wheeling, WV 5F (01/07/2014) -10F (01/07/2014)

Morgantown, WV 7F (01/07/2014) -9F (01/28/2014)
(01/28/2014) (01/29/2014)

New Philadelphia, OH 6F (01/16/2009) -18F (01/28/2014)
(01/28/2014)
(02/15/2015)

Zanesville, OH 6F (01/28/2014) -20F (01/29/2014)

DuBois, PA 0F (01/07/2014) -17F (02/16/2015)

In addition, Pittsburgh has not seen a daytime high below 4F since January of 1994. Pittsburgh has also has not seen 2 consecutive days of high temperatures less than 10F since January of 1997. If you extend this statistic to 3 days, you would have to go back to February 1899.

The last time Pittsburgh's minimum temperature was less than or equal to -5F was December 2022. Last time it was below or equal to -10F was February 2015. For 2 consecutive days of lows less than or equal -10F, you would have to go back to January of 1994.

PBZ WATCHES/WARNINGS/ADVISORIES
PA...Cold Weather Advisory until 1 PM EST Wednesday for PAZ007>009- 013>016-020>022-029-031-073-075-077.
Extreme Cold Warning until 1 PM EST Wednesday for PAZ074-076- 078.
OH...Cold Weather Advisory until 1 PM EST Wednesday for OHZ039>041- 048>050-057>059-068-069.
WV...Cold Weather Advisory until 1 PM EST Wednesday for WVZ001>004- 012-021-509>511.
Extreme Cold Warning until 1 PM EST Wednesday for WVZ512>514.