Sunrise 5:44 AM   Sunset 8:32 PM Moonrise 12:20 AM   Moonset 10:35 AM

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ANZ538 Patapsco River Including Baltimore Harbor- 433 Am Edt Wed May 29 2024
Rest of the overnight - NW winds 5 kt. Waves less than 1 ft. Today - W winds 5 kt. Waves less than 1 ft. Showers likely with a chance of tstms. Tonight - NW winds 5 to 10 kt. Waves 1 ft. A chance of showers and tstms. Thu - N winds 10 kt. Waves 1 ft. Thu night - N winds 5 to 10 kt. Waves 1 ft. Fri - N winds 5 to 10 kt. Waves 1 ft. Fri night - NW winds 5 kt. Waves less than 1 ft. Sat - E winds around 5 kt. Waves flat. Sun - S winds 5 to 10 kt. Waves 1 ft or less.
winds and waves higher and visibilities lower in and near tstms.

ANZ500 433 Am Edt Wed May 29 2024
Synopsis for the tidal potomac and md portion of the chesapeake bay -
a cold front will move over the waters wendesday night. High pressure will follow later this week and into the start of the weekend. Small craft advisories may be needed for portions of the waters Wednesday night into Thursday.

FXUS61 KLWX 290801 AFDLWX

Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 401 AM EDT Wed May 29 2024

SYNOPSIS
A cold front will move through the area tonight. In the wake of the front, high pressure will gradually build in from the Great Lakes through Saturday, before retreating offshore early next week.

NEAR TERM /THROUGH TONIGHT/
Current water vapor imagery (as of 3 AM) shows broad longwave troughing in place across the Great Lakes and East Coast. A prominent shortwave is evident across Northern Indiana. Over the course of the day, this shortwave will dive east-southeastward into the base of the larger longwave trough, eventually tracking over the northern half of the forecast area later this afternoon into this evening.

Skies should start out mostly sunny this morning, but clouds will be on the increase through the late morning, and especially into the early afternoon hours as the surface heats, temperatures cool aloft, boundary layer mixing deepens, and large scale ascent attendant to the approaching shortwave starts to overspread the area. Showers and thunderstorms may reach western Maryland and portions of the West Virginia Panhandle by as early as mid-morning. Most recent CAMs show these showers and thunderstorms organizing and growing upscale in a north-south oriented line along the leading edge of stronger forcing for ascent attendant to the approaching mid- level shortwave. This initial line should gradually track eastward, impacting areas to the west of the Blue Ridge during the late morning and early afternoon hours, and then locations to the east of the Blue Ridge during the mid-late afternoon hours. Additional showers and storms should develop in the wake of this initial line, and gradually rotate across the forecast area during the late afternoon and evening hours.

The parameter space that storms will be moving into doesn't look overly threatening, with only around 200-400 J/kg of MLCAPE ahead of the initial line, and relatively weak flow in the boundary layer. Flow does increase markedly in the mid-upper levels, but storms should somewhat low-topped, making effective shear values only around 20-30 knots. Strong surface heating this morning beneath sunny skies, and rapid cooling in the mid- levels will lead to steep low-level lapse rates (nearly dry adiabatic in the 0-3 km layer), with somewhat of an inverted-V profile in the boundary layer ahead of the initial line. As a result, storms may be capable of producing gusty winds in spite of the unimpressive CAPE/shear parameter space, especially if they become well organized in a linear fashion. CAMs (which are usually underdone with convective winds) show a lot of gusts in the 30-40 knot range with this initial line of storms. Some small hail also can't be ruled out, given very low freezing levels and some CAPE present through the hail growth zone. The threat for both gusty winds and small hail should be minimized in the wake of the initial line, within an environment characterized by more saturated profiles. Some brief heavy downpours may be possible with the storms today, but flooding isn't anticipated in an environment with low PWAT values (around 1 inch) and enough flow in the mid- upper levels that storms should stay progressive in nature.

Any leftover showers and storms should rapidly weaken and lift off toward the northeast this evening with loss of daytime heating. Clouds will be on the decrease as well, and winds will start to pick up out of the northwest as a cold front crosses the area. Some patchy fog may be possible later tonight in some of the most sheltered valleys, but most locations should maintain enough wind to preclude fog formation. Low temperatures overnight will generally be in the 50s.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/
Yet another shortwave trough will descend down in northwesterly flow from the Great Lakes during the day Thursday. This final shortwave will move overtop a very dry boundary layer, with dewpoints only in the 40s in the wake of tonight's cold front.
Despite the moisture starved boundary layer, ascent tied to this shortwave should lead to an uptick in cloud cover Thursday afternoon, and may even produce a few showers or even a brief thunderstorm, especially across central Virginia. Highs on Thursday will be in the low to mid 70s.

Thursday's shortwave will progress off to the east Thursday night into the day Friday. As large scale subsidence start to increase in the wake of the departing trough, high pressure will start to build in from the Great Lakes. Sunny skies and light northerly winds are expected during the day Friday. High temperatures will reach into the low-mid 70s, and we'll have a dryness to the air more typical of early spring, with dewpoints holding in the upper 30s and lower 40s.

Clear skies are forecast for both Thursday night and Friday night. There should be enough of a pressure gradient to maintain a light wind across much of the area Thursday night, but sheltered mountain valley may decouple late in the night. As the surface high moves closer Friday night, more locations should be able to decouple. The combination of clear skies, light winds, and low dewpoints should lead to ideal radiational cooling conditions, and a very chilly night to start off the month of June. Most locations should see low temperatures in the 40s, but cooler mountains valleys may drop back into the 30s and potentially even see some frost.

LONG TERM /SATURDAY THROUGH TUESDAY/
High pressure will nearly be overhead early Saturday and continue to slowly move further southeast. Dry conditions with mostly sunny skies are expected for the day with highs in the upper 70s to low 80s. By Saturday night, clouds will increase a bit with lows dropping down into the low to mid 50s for most areas.

As the high drifts further east and a series of shortwaves moves near the Mid-Atlantic, expect clouds to increase along with precipitation chances to return. For now, high temperatures will be in the upper 70s to low 80s Sunday into Monday with renewed rain and thunderstorm chances each afternoon and evening especially. Warmer air returns Tuesday into midweek next week, with highs climbing into the low to mid 80s for most areas. Best chances for active, strong storms may be Tuesday given the latest guidance. We will continue to monitor this threat over the next several days.

AVIATION /07Z WEDNESDAY THROUGH SUNDAY/
Prevailing VFR conditions are expected through Friday. Showers and thunderstorms this afternoon may lead to temporary drops to sub-VFR conditions. Mid-afternoon looks to be the most likely time for thunderstorms at most of the terminals, and VCTS has been timed out as best as possible at the individual TAF sites.
Showers and thunderstorms will winds down this evening with loss of daytime heating. Drier conditions are expected tonight through Friday. Winds will be out of the west today, northwest tonight into tomorrow, and then out of the north on Friday.

VFR conditions are expected Saturday into Sunday with high pressure nearby or overhead. A slight chance for a few thunderstorms is possible later in the day on Sunday for some of the western terminals like KCHO and KMRB.

MARINE
Sub-SCA westerly winds are expected over the waters today, but SMWs may be possible as storms move over the waters later this afternoon into this evening. A cold front will cross over the waters later tonight, with winds shifting to out of the northwest behind the front. Winds may near low-end SCA levels in northwesterly flow later tonight into the day tomorrow. Lighter northerly flow is expected over the waters on Friday.

Winds will be below SCA criteria Saturday into Sunday with nearly calm winds on Saturday turning southerly on Sunday while remaining light. Cannot rule out an isolated thunderstorm over the waters Sunday afternoon/evening.

&

TIDES/COASTAL FLOODING
Offshore flow will continue through Thursday. This will lead to lower water levels. No tidal flooding is expected through Thursday, but Annapolis and DC may potentially reach Action Stage around high tide.

LWX WATCHES/WARNINGS/ADVISORIES
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.

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Chain Bridge
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Wed -- 01:15 AM EDT     Moonrise
Wed -- 01:28 AM EDT     2.97 feet High Tide
Wed -- 05:45 AM EDT     Sunrise
Wed -- 08:03 AM EDT     0.57 feet Low Tide
Wed -- 11:33 AM EDT     Moonset
Wed -- 01:37 PM EDT     3.27 feet High Tide
Wed -- 08:26 PM EDT     Sunset
Wed -- 08:51 PM EDT     0.39 feet Low Tide
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