Marine Weather and Tide Forecast for Kings Park, VA

KEY MESSAGES
- 1) Frost Advisories start the day in the Allegheny Mountains, followed by a dry and seasonable afternoon.

- 2) Milder for the weekend with chances for showers and thunderstorms.

- 3) Cooler temperatures early next week moderate mid week.

DISCUSSION
KEY MESSAGE 1...Frost Advisories start the day in the Allegheny Mountains, followed by a dry and seasonable afternoon.

A subtle front/dew point boundary has been pushing across the area overnight. Northwest winds are increasing briefly behind the front, which seems to be dispersing earlier fog in the Virginia foothills and piedmont. Surface high pressure is building toward southern West Virginia. Winds are lessening across the valleys of the Alleghenies, so some frost development remains possible through sunrise. A Frost Advisory remains in effect until 8 AM.

After a sunny start, some high based cumulus clouds should develop in response to daytime heating this afternoon. Westerly wind gusts will also increase due to the deep boundary layer, especially across the northern half of the area. Temperatures will rebound nicely after a cool start, ultimately reaching highs in the upper 60s to lower 70s. Winds will quickly become southerly this evening, which will help keep low temperatures a bit milder in the mid 40s to mid 50s.

KEY MESSAGE 2...Milder for the weekend with chances for showers and thunderstorms.

As surface high pressure moves offshore, a warm front will lift north through the area Saturday, ushering in milder temperatures. Highs Saturday rise into the mid 70s, while Sunday could rise into the upper 70s to low 80s (subtract 7-10 degrees for mountain locations.

There's still some uncertainty with rain chances and timing for Saturday. Some light rain showers may move across during the morning hours with an initial shortwave trough and push of warm advection, especially across the northern half of the area.
Clouds may break somewhat during the afternoon, and some scattered convection may develop along a prefrontal trough.
Shear will be sufficient for organized storm structures, but dew point recovery will be modest (50s) with instability likely limited to several hundred J/kg. Thus the severe weather risk appears low, but will have to monitor the potential for small hail and gusty winds.

Much of Saturday night and Sunday morning should be dry. After that, a cold front will slowly settle in from the northwest, eventually crossing the area Monday. A wave of low pressure will eventually form along the boundary as stronger troughing digs southeastward from the Great Lakes. This could ultimately bring a steadier rainfall to parts of the area, but these details remain uncertain. The highest chances for rain will be Sunday night into Monday morning. While a few thunderstorms could be in the mix, overall instability should be minimal through the period.

KEY MESSAGE 3...Cooler temperatures early next week moderate mid week.

High pressure will quickly build in from the west Monday night. This will result in light winds and favorable radiational cooling conditions. Frost or near freezing temperatures could result in the sheltered valleys near and west of I-81.

The high pressure will drift offshore Tuesday marking return flow and moderating temperatures. The warming trend will be more noticeable heading into Wednesday as a warm front lifts into the region, followed by a cold front by Thursday. This frontal system will bring a chance of showers and a few thunderstorms mid week.

AVIATION /07Z FRIDAY THROUGH TUESDAY/
A weak boundary is crossing the area this morning, which shifted winds to the northwest and cleared out the fog/low clouds from CHO. VFR conditions are then likely through the night, with some high based cumulus this afternoon, and mid level ceilings tonight.

Winds will become more westerly through today and may gust to around 20-25 kt during the afternoon. Winds turn southerly quickly this evening and persist through Saturday, when some additional 20 kt gusts are possible. Some light showers are possible Saturday morning, with isolated to scattered showers and thunderstorms possible in the afternoon, especially near the metro terminals.

VFR conditions can be expected for much of Sunday. However, a cold front will drop into the area late in the day. Widespread rain and a few thunderstorms can be expected as this front traverses the region, especially Sunday night into Monday morning. Expect VSBY reductions and reduced CIGs during this time.

Any lingering rain chances should pull offshore by midday Monday resulting in VFR conditions and north to northwest winds. Gusts may reach 20 to 25 knots in the wake of the front Monday before becoming lighter Monday night into Tuesday and shifting to the south.

MARINE
A weak front is crossing the area early this morning, shifting winds to the northwest. Some gusts to around 20 kt are occurring in the wake of this front but appear to be lasting only and hour or two at most locations. Thus have this covered with a Marine Weather Statement.

By this afternoon, winds will generally be out of the west to southwest. Gusts are forecast to reach low-end SCA levels across the narrower waters of the Upper Bay and Upper Tidal Potomac. Winds become southerly quickly this evening. Another SCA has been issued south of Sandy Point as southerly channeling is expected to increase through the night. All waters may need an advisory Saturday as southerly flow continues. Isolated to scattered thunderstorms may affect the waters Saturday afternoon and early evening.

Lighter winds are expected Saturday night into Sunday. Showers and perhaps a few thunderstorms along a cold front will likely cross the waters mainly Sunday night into Monday morning. The associated cold front will cross the waters early Monday with a shift to northwesterlies with gusts up to 20 to 25 knots. Small Craft Advisories will likely be needed late Sunday night through part of Monday night. Building high pressure will result in lighter winds by Tuesday before shifting to the south.

TIDES/COASTAL FLOODING
Southerly flow is expected late Friday afternoon through Saturday night. Flow may be occasionally enhanced by southerly channeling, but may also exhibit a bit west-of-south component at times. This makes the tide forecast somewhat uncertain, as a more south to slightly east-of-south component at slightly higher speeds would result in higher water levels approaching 1.5 feet above normal and a resulting higher potential for minor flooding at places like Annapolis and Havre de Grace heading into Saturday. Wind direction may be a bit more variable Sunday into Sunday evening introducing further uncertainty to the tide forecast, though lingering elevated water levels certainly seem plausible until a cold front crosses Sunday night into Monday.

LWX WATCHES/WARNINGS/ADVISORIES
DC...None.
MD...Small Craft Advisory from 11 AM this morning to 6 PM EDT this evening for MDZ008.
Frost Advisory until 8 AM EDT this morning for MDZ509-510.
VA...Frost Advisory until 8 AM EDT this morning for VAZ503-504.
WV...Frost Advisory until 8 AM EDT this morning for WVZ501-505-506.
MARINE...Small Craft Advisory from 11 AM this morning to 6 PM EDT this evening for ANZ530-531-535-538.
Small Craft Advisory from 6 PM this evening to 6 AM EDT Saturday for ANZ532>534-537-540-541-543.