Marine Weather and Tide Forecast for Galesville, MD

KEY MESSAGES
1) Widespread freeze late tonight into Tuesday morning as high pressure builds over the region.

2) Warming temperatures mid to late week with additional rain chances possible this weekend.

DISCUSSION
KEY MESSAGE 1...Widespread freeze late tonight into Tuesday morning as high pressure builds over the region.

The upper level trough and secondary cold front responsible for the gusty graupel showers earlier this morning/afternoon continues to push offshore this evening. Breezy conditions remain with gusts out of the northwest at 15 to 30 mph. Winds will slowly decrease prior to midnight setting us up for a widespread freeze heading into early Tuesday morning.

Canadian high pressure builds over the region late tonight into Tuesday leading to lighter winds (less than 15 kts) across the region. This will lend to a perfect radiational cooling set up with clear skies and lightening winds allowing temps to fall. Widespread freeze conditions are expected for most of the area aide from the major urban centers and areas directly influenced by larger bodies of water. Some frost may also be noted, but given some elevated wind and ample dry air in place, the threat may be limited.

For context, this is ~10 days past the median date of the last spring freeze based on 1991-2020 climatology for areas along/east of I-81. Given the warmth early this spring, many areas are ahead of schedule from a growth stand point, so this freeze could be rather impactful.

There are no frost/freeze headlines for the Alleghenies as the growing season has not started there yet.

KEY MESSAGE 2...Warming temperatures mid to late week with additional rain chances possible this weekend.

As Canadian high pressure slides off toward the south, a quick moving cold front will cross the region by mid-week (late Tuesday night into Wednesday). There will not be a whole lot of moisture to work with, so any rainfall amounts are likely to be meager in nature (less than a 0.10"). Some instability in the atmosphere could produce a few thunderstorms, particularly during the afternoon hours. A lack of stronger forcing, shear, or instability should lead to generally weak convection, though some spotty downpours, gusty winds, and small hail can't be ruled out.

After a chilly start to the work week, ensembles agree on a warm up through the middle to latter portions of the week. High temperatures could push back into the low/mid 80s by Friday ahead of another system likely to bring a return of rain by the second half of Friday. A threat of showers continues through much of the weekend before the frontal system exits east of the region by late in the weekend. On Sunday, the latest forecast package calls for highs returning to the 60s. This eventually all lends itself to a cooler finish to the month of April.
However, there is uncertainty in the evolution of low pressure approaching the area by then, and just how the temperature and precipitation forecast pans out. The good news is that rain chances are back in the forecast given the expanding drought and elevated fire weather concerns across the region.

AVIATION /00Z TUESDAY THROUGH SATURDAY/
High level scattered to broken clouds continue to diminish as the secondary front/upper trough push offshore. Some upslope clouds remain along the Alleghenies in northwest flow with FEW-SCT stratocumulus north and east of KIAD/KDCA. All terminals will flip over to SKC conditions later this evening ands into tonight with high pressure building overhead. It will be rather chilly tonight with a widespread frost/freeze possible early Tuesday morning across all terminals as high pressure settles overhead.

VFR conditions continue Tuesday through Friday. Some temporary sub- VFR conditions are possible with a weak cold front Wednesday. The front could bring brief -SHRA/-TSRA at the terminals Wednesday morning into Wednesday afternoon. Locations down around KCHO may see nothing at all. Winds shift to the south Tuesday at less than 15 kts with southwest winds ahead of the front Wednesday switching back to the northwest Wednesday afternoon. Gusts Wednesday will remain between 10 to 20 kts.
Some LLWS also possible west of the corridor Tuesday night as southerly flow increases ahead of the boundary.

Additional WAA showers are possible by Friday afternoon which could be accompanied by a few restrictions. Initial winds will be out of the NW on Thursday before becoming mainly westerly on Friday. A shift to southeasterly is possible by Friday night.
More shower chances with temporary sub-VFR reductions are possible this weekend.

MARINE
High pressure builds overhead late tonight into Tuesday. Light winds tonight turn southerly Tuesday with additional SCAs possible late Tuesday into Wednesday due to southerly channeling. Sub-SCA level winds are expected late Wednesday with winds out of the SW to NW as a cold front crosses. This front may bring a few showers and thunderstorms mainly Wednesday afternoon.

Expect sub-advisory level winds for both Thursday and Friday.
Weak gradients will favor multiple wind shifts before turning mainly S/SE by Friday night.

SCA conditions return for portions of the waters this weekend.

FIRE WEATHER
Much cooler temperatures are expected through Tuesday with a moderating trend in temperatures expected during the middle and second half of the week. Winds will be on light side starting tonight thanks to high pressure overhead, but humidities will be marginally low to near critical levels. The next potential for rainfall is Wednesday into Thursday (mainly north of I-66/US-50), but amounts look light.

Special Weather Statements may be needed for portions of the Shenandoah Valley and central VA Piedmont Tuesday afternoon.
Elsewhere, winds should remain light enough to reduce fire weather concerns.

TIDES/COASTAL FLOODING
Southerly flow is expected Tuesday into Tuesday night. This will result in rising tidal anomalies. The higher members of P-ETSS and SFAS, as well as STOFS and CBOFS all hint at the potential for minor flooding at Annapolis early Wednesday as a result.

LWX WATCHES/WARNINGS/ADVISORIES
DC...Freeze Warning from 2 AM to 10 AM EDT Tuesday for DCZ001.
MD...Small Craft Advisory until 9 PM EDT this evening for MDZ008.
Freeze Warning from 2 AM to 10 AM EDT Tuesday for MDZ003>006- 008-011-013-014-016>018-503>508.
VA...Freeze Warning from 2 AM to 10 AM EDT Tuesday for VAZ025>031- 036>040-050-051-053>057-501-502-505>508-526-527.
WV...Freeze Warning from 2 AM to 10 AM EDT Tuesday for WVZ051>053.
MARINE...Small Craft Advisory until 9 PM EDT this evening for ANZ530- 531-535-536-538>540-542.
Freeze Warning from 2 AM to 10 AM EDT Tuesday for ANZ530.
Small Craft Advisory until 4 AM EDT Tuesday for ANZ532>534-537- 541-543.