Marine Weather and Tide Forecast for Annapolis Neck, MD

KEY MESSAGES
- 1) Low pressure will ride along a frontal boundary later tonight and during the day Sunday. A mix of rain and snow will transition to all snow.

- 2) Very cold conditions are expected over the region Monday night through Tuesday night, with below normal temperatures continuing through the remainder of the week.

DISCUSSION
KEY MESSAGE 1...Low pressure will ride along a frontal boundary later tonight and during the day Sunday. A mix rain and snow will transition to all snow.

A front bisecting the region will be the focal zone of an area of low pressure that will develop along it and move toward the east as the front slides to the south and east. Many locations will be in the middle to upper 30s in the areas that are expected to encounter accumulating snow late tonight and Sunday.
As we approach daybreak Sunday morning, these temperatures will slowly drop a degree every hour or two to reach close to or below the freezing mark as precipitation begins. A mix of rain and snow could start between 4am and 6am in eastern Maryland and eastern Virginia, before the atmosphere cools down evenmore with falling precipitation. Thus, the cold atmosphere will support accumulating snowfall through much of the day Sunday.

East of I-95, more precipitation is expected, but temperatures may be slightly above freezing for a large part of the event, and precipitation may even be rain for a while. The best potential for cold air and higher precipitation totals to overlap appears to be central and northeastern Maryland, northeastern Virginia. The model trend has been bringing snowfall farther to the northwest; thus, resulting in the potential for accumulating snowfall of 1 to 3 inches instead of a dusting to near an inch. The Winter Weather Advisory previous issued has been expanded to the west, southwest and south. Much of central Maryland, far northeast Virginia, Baltimore and Washington DC has been included. End time for the precipitation could be pretty early in the day closer to and west of the Blue Ridge. How long the precipitation lasts closer to the Chesapeake Bay will depend on the western extent of the second frontal wave. In any event, dry conditions look likely by mid Sunday evening. Temperatures from the mid teens to mid 20s are expected Sunday night, so any residual moisture or slush could refreeze.

KEY MESSAGE 2...Very cold conditions are expected over the region Monday night through Tuesday night, with below normal temperatures continuing through the remainder of the week.

Behind an Arctic front that crosses the region early on Monday expect very cold conditions to settle in for the start of the week.
Well below normal temperatures are expected through at least Wednesday, with a slight reprieve on Thursday, then another reinforcing shot of cold air arrives for Friday.

Highs are going to remain in the 30s to around 40F each day, with Tuesday being the coldest as the entire area remains below freezing during the daytime. It will be particularly cold Monday night and Tuesday night with lows in the single digits to teens. When factoring in the winds, expect wind chills to be in the single digits, with around -10F to -15F in the mountains. Again, the coldest wind chills are forecast for Monday night into Tuesday morning when a reinforcing upper trough and secondary cold front cross the area.

By Thursday, the temperatures return to seasonal values of highs in the 40s and lows in the 20s. At this point in the week model guidance is some consensus in tracking a cold front across the area Thursday afternoon/evening. This could bring a slight rain/snow mix to parts of the area, though precip chances overall are low at 20-30 pct. Cold air surges in behind the front to close the week.

Per the 12Z models and early ensemble guidance the synoptic pattern could become volatile for next weekend. A northern stream and southern stream system interact over the central CONUS, eventually pushing a deepening low pressure system and strong cold front across the Mid-Atlantic. Few details are certain beyond that, so continue to monitor the forecast through the upcoming week for what could be the next possible round of widespread wintry precip next weekend.

AVIATION /02Z SUNDAY THROUGH THURSDAY/
VFR conditions will continue until late tonight. A cold front arriving the second half of the night will bring more definitive northwest winds as well as lowering ceilings.

Low pressure passing on the front along the coast will likely bring a little snow or a rain/snow mix to many of the terminals Sunday. Some light slushy accums and a period of IFR conditions in snow and low ceilings are becoming increasingly likely, though temps will be marginal and the system will be fast- moving. Lowest chance of precip/IFR is at MRB, with fairly brief durations at IAD and CHO. Precip may last longer at DCA and especially BWI/MTN. There are some indications of a midday break, with additional snow possible at these eastern terminals in the afternoon. N/NW winds may briefly gust to around 15 kt Sunday afternoon and evening as the low pulls away. VFR conditions should return fairly quickly after precip ends.

VFR conditions are expected Monday through Wednesday behind a strong arctic front. The main aviation impact will be gusty northwest winds each day that gust around 20-25 knots. Monday looks to be the gustiest day, with possible gusts up to 30-35 knots in the afternoon.

MARINE
An uptick in winds Sunday afternoon and evening as low pressure passes offshore. This low is also expected to bring light snow or a rain/snow mix, which will reduce visibility over the waters on Sunday.

SCA conditions are likely for MLK Day into Tuesday behind a strong arctic front. Northwest winds gust between 20-25 knots across all the waters, with gusts up to 30 knots possible Monday afternoon. Winds remain at SCA levels Monday night through Tuesday afternoon, then decrease below SCA levels Tuesday night.
Another round of SCA conditions is possible Wednesday afternoon. Freezing temperatures could result in ice buildup on the local waters, especially in the small tributaries.

LWX WATCHES/WARNINGS/ADVISORIES
DC...Winter Weather Advisory from 4 AM to 6 PM EST Sunday for DCZ001.
MD...Winter Weather Advisory from 4 AM to 6 PM EST Sunday for MDZ005-006-008-011-013-014-503>508.
VA...Winter Weather Advisory from 4 AM to 6 PM EST Sunday for VAZ053-054-506-526-527.
WV...None.
MARINE...Winter Weather Advisory from 4 AM to 6 PM EST Sunday for ANZ530.