Sunrise 6:29 AM   Sunset 7:49 PM Moonrise 11:53 AM   Moonset 2:20 AM

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ANZ535 Tidal Potomac From Key Bridge To Indian Head- 442 Am Edt Tue Apr 16 2024
Rest of the overnight - N winds 5 kt. Waves less than 1 ft. Today - E winds 5 kt. Waves less than 1 ft. Tonight - S winds 5 kt. Waves less than 1 ft. Wed - SE winds 5 to 10 kt. Waves 1 ft. Showers likely. Wed night - SE winds 5 to 10 kt. Waves 1 ft. Showers likely with a chance of tstms. Thu - NW winds 5 to 10 kt. Waves 1 ft. A chance of showers. Thu night - NE winds 5 to 10 kt. Waves 1 ft. Fri - SE winds 5 kt - .becoming sw after midnight. Waves 1 ft. A chance of showers through the night. Sat - NW winds 10 to 15 kt. Waves 1 ft.
winds and waves higher and visibilities lower in and near tstms.

ANZ500 442 Am Edt Tue Apr 16 2024
Synopsis for the tidal potomac and md portion of the chesapeake bay -
a cold front will settle near the virginia and north carolina border during the day Tuesday. This front will eventually return northward as a warm front Wednesday before another cold front crosses the waters Thursday morning. A stronger cold front approaches the region by late in the work week. Small craft advisories may be needed during the middle of the week.

FXUS61 KLWX 160757 AFDLWX

Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 357 AM EDT Tue Apr 16 2024

SYNOPSIS
A cold front will drift to the south today before stalling near the Virginia/North Carolina border. This boundary returns northward as a warm front on Wednesday. A weak cold front tracks through on Thursday before a stronger cold front arrives early in the weekend. High pressure returns on Sunday and into early next week.

NEAR TERM /THROUGH TONIGHT/
The latest surface observational datasets indicate the cold front has slowly pushed south of I-66/U.S. 50. This is most evident in the increase in northerly winds in the wake of the frontal passage. A couple hour period of 20 to 25 mph gusts are possible as this system continues its southward trek toward the I-64 corridor. While temperatures are very mild right now with most reporting readings in the 60s, there is a notable dew point fall as this boundary tracks through. 3-hour falls are on the order of 15 to 20 degree dew point drops. This southward push is expected to persist through this afternoon before the system stalls near the Virginia-North Carolina border.

In the wake of this frontal passage, expect a cool down relative to the 80 degree plus readings observed on Monday. Low to mid 70s are likely across a vast majority of the area. Have opted to lower dew point/humidity levels given the likelihood that dry air at the top of the mixed layer reaches the surface.

Heading into the afternoon to evening hours, showers and isolated thunderstorms are expected across the Allegheny Highlands toward the Shenandoah Valley. Most high-resolution models do not show instability pushing too far east off the Allegheny Front. Thus, expect the main convective chances to focus over the higher terrain. Severe weather threats appear a lot lower given weaker shear profiles and somewhat questionable forcing mechanisms. Shower activity edges eastward through the evening before mainly waning overnight. Expect seasonably mild night conditions at night with low temperatures in the low/mid 50s. This is roughly 10 to 15 degree above mid-April climatology.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/
On Wednesday morning, the warm front is expected to stretch from northwest to southeast across the area. Its northward progression appears sluggish at times as the system struggles to reach the Mason-Dixon Line on Wednesday. Given this artifact of the forecast, locations to the north will likely see a cooler day than those south of I-66. The latest forecast package depicts mainly low to mid 70s across the region, while mid/upper 60s are more commonplace along I-70 and points northward. The warm sector should have the best chances for any convective activity, with rain showers being likely over most of the area.
Weak height falls aloft coupled with increasing low-level warm advection should allow for greater convective coverage than Tuesday. Although northeastern Maryland remains in the cool sector through this evening and night, some elevated convection is possible as indicated in the forecast package. Nighttime conditions will stay mild with lows in the 50s.

Heading into Thursday, the shortwave responsible for the previous day's activity is forecast to track up into New England and southern Quebec. A weak/diffuse cold front will track through the region on Thursday leading to a shift to north- northwesterly winds. Shortwave ridging in the wake should help temper some of the shower chances. However, will maintain around a 20 to 30 percent chance through the day. Do expect a vast majority of the day to be dry, accompanied by a mix of clouds and sun. Locations in central Virginia should see more sunshine which will favor high temperatures rising into the upper 70s to low 80s. On the converse are the Allegheny Front and northeastern Maryland which each may be confined to the 60s.
Winds shift to east to northeasterly overnight with lows falling into the mid 40s to low 50s.

LONG TERM /FRIDAY THROUGH MONDAY/
Upper ridging will be departing off the coast Friday while a cold front approaches from the west. While timing and placement of features still have some uncertainty, it appears the cold front will push into/through the area Friday or Saturday, representing the highest chances for rain showers. A relatively stable atmosphere and lack of rich moisture will keep thunderstorm chances to a minimum.
The front won't push to the southeast very fast, and there is some potential for a wave of low pressure to ride along the boundary and produce additional rain chances over the weekend. While not zero, rain chances decrease by Monday as there is some consensus for high pressure to build in from the west.

Temperatures Friday and Saturday may depend somewhat on cloud cover and rainfall, but have potential to remain above normal. The greater signal for cooler (near or below normal) temperatures arrives Sunday and Monday as upper troughing pushes east of the area.

AVIATION /08Z TUESDAY THROUGH SATURDAY/
A slow moving cold front will continue to drop southward through the area today. In the wake, winds shift to mainly north to northeasterly. However, this is likely to be short lived as this frontal system eventually returns northward as a warm front later today. Expect mainly south to southeasterly winds the second half of the day and into tonight. The main shower chances should stay west of the terminals although did include a VCSH line in the KCHO TAF between 7-11 PM. Otherwise, VFR conditions are in store for the terminals.

Shower and thunderstorm chances increase on Wednesday as the warm front tracks northeastward across the area. The best chance for thunder would be at KCHO, KMRB, KDCA, and KIAD. It is difficult to say how far north this system is able to track.
Regardless of convective threats, rain showers are likely on Wednesday which will lower ceilings into the MVFR to near IFR ranges. MVFR to IFR conditions linger into Wednesday night across the Baltimore terminals. By Thursday, although a few showers are possible, expect mainly VFR conditions along with northwesterly winds. These shift to northeasterly overnight.

Sub-VFR conditions are possible at times Friday and Saturday as a cold front brings potential low ceilings and rain showers.

MARINE
Given enhanced northerly gusts behind the slow moving cold front, Small Craft Advisories are in place until 6 AM this morning for the wider Chesapeake Bay waters. Gusts of 20 to 25 knots have already been observed and will continue the next couple of hours. Wind fields stay below advisory levels through Thursday morning before ramping back up on Thursday afternoon/evening behind a cold front. Some portions of the waters may need Small Craft Advisories with this surge. Such winds gradually weaken into late Thursday night.

Convective threats mainly focus on Wednesday into Wednesday night as a warm front pushes northeastward across the area.
Special Marine Warnings would be needed for any of the more robust activity. The atmosphere looks more stable on Thursday as a cold front pushes through the region.

Onshore flow likely remains below SCA criteria Friday. A cold front will likely push to the south Saturday, and SCA conditions will be possible in WNW flow in its wake.

TIDES/COASTAL FLOODING
While some action stages may be reached through the middle of the week, the greater water level rises and potential for near- minor flooding appears to be toward Friday as onshore flow develops ahead of a low pressure system.

LWX WATCHES/WARNINGS/ADVISORIES
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 6 AM EDT early this morning for ANZ531>534-538.

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Chain Bridge, Washington, D.C., Tide feet

Chain Bridge
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Tue -- 03:18 AM EDT     Moonset
Tue -- 03:38 AM EDT     2.84 feet High Tide
Tue -- 06:29 AM EDT     Sunrise
Tue -- 09:55 AM EDT     0.60 feet Low Tide
Tue -- 12:51 PM EDT     Moonrise
Tue -- 03:55 PM EDT     2.96 feet High Tide
Tue -- 07:47 PM EDT     Sunset
Tue -- 10:48 PM EDT     0.58 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Chain Bridge, D.C., Tide feet

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