Marine Weather and Tide Forecast for Leonard, MD

KEY MESSAGES
- 1) An Arctic air mass will remain in place through the weekend with dangerously cold wind chills.

- 2) A strong coastal low will bring bitter to extreme cold wind chills Saturday night into Sunday.

- 3) Chance of light snow mid next week.

DISCUSSION
KEY MESSAGE 1...An Arctic air mass will remain in place through the weekend with dangerously cold wind chills.

Temperatures as of mid morning were in the single digits and teens with light winds resulting in wind chills near or below zero in many spots. Temperatures will rise a bit through midday with high clouds building across.

Wind chill values tonight will be again close to zero, so new cold weather headlines were issued. The coldest wind chill values are expected Saturday night into Sunday morning which latest forecast has values reaching solidly into the advisory range and in the warning category in the Allegheny Mountains.

KEY MESSAGE 2...A strong coastal low will bring blustery conditions with extreme cold wind chills Saturday night into Sunday.

00Z trends from the global models, particularly from the 00Z ECMWF, showed coastal low pressure tracking further south when compared to the 12Z runs from yesterday. Probs of 0.1" QPF remain below 30% across the southern half of St. Mary's County.
In addition, 850 mb dewpoint depressions are forecast to exceed more than 10C making it difficult for any snow to reach the ground. The best chance for a dusting of snow seems to be over Nelson County VA during the day Saturday. The main impact from this storm will be the cold and wind with gusts in the 35-40 mph range creating bitter to extreme cold wind chills.

KEY MESSAGE 3...Chance of light snow mid next week.

A shortwave-trough is fcst to dive from the Northern Plains into the mid Mississippi River Valley Tue afternoon into Wednesday. This feature is then forecast to become a closed low and induce sfc cyclogenesis across the Southeast. The Canadian model shows the weakest and most southern solution while the ECMWF the strongest and a more favorable track. This latest 00Z EC solution is a significant break in continuity to prior runs that showed a weaker solution and snow amounts between a trace and one inch. The EPS and EC AIFS suggest that the deterministic Euro is likely overdone and show a much weaker solution. The EPS shows the probs of 0.01" of QPF in the 60-70% range and of 0.1" QPF in the 30-50% range across the area in the 12Z Wed-00Z Thu time frame.

AVIATION /14Z FRIDAY THROUGH TUESDAY/
VFR conditions are expected through the TAF period except perhaps at KCHO where MVFR CIGs and flurries are possible overnight into Saturday. NW winds 5-10 kts except at KCHO where winds will be more E/NE into the evening. Winds will be more N this weekend becoming gusty late Sat through Mon. Clouds increase this weekend, but snow likely stays SE of the TAF sites. Winds become lighter later Mon.

A wave of low pressure approaching from the OH Valley could bring snow by mid week.

MARINE
Winds are expected to diminish further later today as sfc ridge axis builds in. Winds begin to strengthen late Saturday as low pressure deepens offshore. Gale conditions appear likely for portions of the waters Saturday night into Sunday morning and a Gale Watch remains in effect. A Heavy Freezing Spray Watch was also issued for the wider waters south of Drum Point where the winds will be strongest, the fetch longer and the waves bigger.
A Freezing Spray Advisory will likely be needed for the ice free waters south of the Bay Bridge and the lower tidal Potomac south of Cobb Island.

TIDES/COASTAL FLOODING
As low pressure rapidly strengthens offshore Saturday night through Monday, strong northerly winds may lead to blowout tide conditions. Some guidance indicates tides as low as 2 to 3 ft below MLLW (lowest Sunday). Due to widespread ice buildup, this could result in some property damage (docks, moorings, etc.) as block ice is pushed away from the shore.

LWX WATCHES/WARNINGS/ADVISORIES
DC...Cold Weather Advisory until 11 AM EST this morning for DCZ001.
Cold Weather Advisory from 8 PM this evening to 11 AM EST Saturday for DCZ001.
MD...Cold Weather Advisory until 11 AM EST this morning for MDZ004>006-008-011-013-014-016>018-501-503>510.
Cold Weather Advisory from 8 PM this evening to 11 AM EST Saturday for MDZ006-008-011-013-014-016>018-503>508.
Cold Weather Advisory from 7 PM this evening to 11 AM EST Saturday for MDZ003>005-501-502-509-510.
VA...Cold Weather Advisory until 11 AM EST this morning for VAZ053- 054-501-503-505>508-526-527.
Cold Weather Advisory from 8 PM this evening to 11 AM EST Saturday for VAZ039-040-050-051-053>057-501-502-505-506- 526-527.
Cold Weather Advisory from 7 PM this evening to 11 AM EST Saturday for VAZ503-504-507-508.
WV...Cold Weather Advisory until 11 AM EST this morning for WVZ501- 503-505.
Cold Weather Advisory from 7 PM this evening to 11 AM EST Saturday for WVZ050>053-055-501>506.
MARINE...Gale Watch from Saturday evening through Sunday evening for ANZ530>543.
Small Craft Advisory from 1 PM to 6 PM EST Saturday for ANZ531- 535-536-538-539.
Small Craft Advisory from midnight tonight to 6 PM EST Saturday for ANZ532>534-537-540>543.
Heavy Freezing Spray Watch from late Saturday night through Sunday morning for ANZ534-543.