Friday, October15, 2021
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Marine Weather and Tides
St. James, MD

Version 3.4
NOTICE
3/30/2021 -- ANZ330 has been split into ANZ331 and ANZ332. Click EDIT in Marine Forecast and select your new zone.
1/26/2021 -- The West Coast Satellite images havd been updated. They now use GEOS-17.
1/1/2021 -- The 7 day forecast are now working well. Thank you NOAA for your support.

Sunrise 7:20AMSunset 6:32PM Friday October 15, 2021 11:25 PM EDT (03:25 UTC) Moonrise 3:37PMMoonset 12:55AM Illumination 75% Phase: Waxing Gibbous; Moon at 10 days in cycle
NOTE: Some of the data on this page has not been verified and should be used with that in mind. It may and occasionally will, be wrong. The tide reports are by xtide and are NOT FOR NAVIGATION.
Marine Forecasts
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ANZ535 Tidal Potomac From Key Bridge To Indian Head- 1037 Pm Edt Fri Oct 15 2021
.small craft advisory in effect from 6 am edt Saturday through late Saturday night...
Rest of tonight..S winds 5 kt. Waves less than 1 ft.
Sat..S winds 5 to 10 kt with gusts to 20 kt... Becoming sw 15 to 20 kt with gusts to 30 kt early in the afternoon, then becoming W 10 to 15 kt with gusts to 30 kt late. Waves 1 to 2 ft. Showers. Vsby 1 nm or less.
Sat night..NW winds 5 to 10 kt with gusts to 25 kt. Waves 1 ft. A chance of showers.
Sun..NW winds 10 to 15 kt with gusts to 25 kt. Waves 1 ft.
Sun night..W winds 5 to 10 kt. Gusts up to 25 kt in the evening. Waves 1 ft.
Mon..W winds 10 to 15 kt with gusts to 25 kt. Waves 1 ft.
Mon night..NW winds 5 to 10 kt with gusts to 20 kt. Waves 1 ft.
Tue..W winds 5 to 10 kt. Waves 1 ft.
Wed..W winds 5 to 10 kt. Waves 1 ft.
ANZ500 1037 Pm Edt Fri Oct 15 2021
Synopsis for the tidal potomac and md portion of the chesapeake bay.. High pressure will remain in place through tonight, while a strong cold front will pass through the region on Saturday. Small craft advisories will be required during the second half of the weekend. Gale conditions are possible Saturday. In the wake of the cold frontal passage, high pressure returns from Monday through Wednesday. Small craft conditions will likely linger into portions of Monday.


7 Day Forecast for Marine Location Near St. James, MD
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location: 39.59, -77.77     debug


Area Discussion for - Baltimore, MD/Washington
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FXUS61 KLWX 160117 AFDLWX

Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 917 PM EDT Fri Oct 15 2021

SYNOPSIS. A strong cold front will cross the region Saturday. High pressure will follow for much of next week before another cold front moves through toward the end of the work week.

NEAR TERM /UNTIL 6 AM SATURDAY MORNING/. A large, deep trough bisects the lower 48 this evening, with an associated strong surface cold front marking the leading edge of a more autumnal airmass. As of 01Z, this boundary is currently moving eastward through the lower Great Lakes back through central Ohio and into western Tennessee/Kentucky. Any remnant showers ahead of this mentioned boundary have decayed given the loss of heating and subsequent instability.

Low temperatures tonight are expected to be well above normal due to continued southerly flow and mid/high clouds. The threat for gusty to severe winds associated with convection may increase near the Allegheny Front by around daybreak Saturday as forcing from the approaching upper trough and front increase.

SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/. A strong cold front is expected to be crossing the Appalachian Crest around or just after daybreak Saturday. It should reach I-95 during the early afternoon hours, then clear the Chesapeake Bay by nightfall. Gusty winds, perhaps augmented by remnant convection from upstream, may intersect the Allegheny Highlands Saturday morning. A relative minimum in shower activity is shown in most guidance between the Allegheny Front and the Blue Ridge due to a dearth of instability. Increasing convergence along the front as well as modest instability (up to around 500 J/kg of CAPE) in the lee of the Blue Ridge and an environment characterized by strong shear of around 50 kts through the lowest 4 km AGL may result in isolated instances of damaging wind gusts with any more robust parts of the anticipated line.

Activity should clear the area by evening, leaving in its wake a stark cooling and drying trend with gusty northwesterly winds. The blustery conditions are expected to persist through the rest of the weekend. Sunday should be dry save for an outside chance of a couple upslope showers along/west of the Allegheny Front.

LONG TERM /MONDAY THROUGH FRIDAY/. An upper-level trough will exit off to the northeast on Monday as ridging slowly builds in from the west. High pressure will become situated overhead through Wednesday bringing dry and more seasonable conditions. A strong pressure gradient should remain in place behind the exiting front bringing gusty northwesterly winds Monday with gusts up to 30 mph possible. The gradient starts to weaken on Tuesday as the high settles overhead and the low pulls further away.

Temperatures are expected to undergo a slight warming trend next week as the high slowly shifts eastward and a weak return flow forms. By the end of the long term period, Thursday evening into Friday, a weak frontal boundary may approach from the west bringing the next chance for showers along with a return to mid 70s highs. The threat for significant rain and thunderstorms appears low for Thursday evening into Friday as the main forcing is currently progged to remain well north.

AVIATION /01Z SATURDAY THROUGH WEDNESDAY/. Mainly VFR conditions are expected through the TAF period with a wind shift to gusty W/NW flow behind a cold front Saturday.

Scattered to broken mid and high level clouds will likely come and go through early Saturday morning amidst light S/SE surface flow of 5-10 kts.

A brief period of low-level wind shear is possible Saturday morning as S/SW flow increases within a few thousand feet of the surface. Then, a band of showers followed by a wind shift to the W/NW is expected in association with a strong cold front late morning through afternoon. This band of showers may not really get going until it's east of the Blue Ridge closer to I-95, with the CHO and MRB terminals having the lowest/briefest chance of rain. Metro terminals likely see shower activity with perhaps isolated lightning strikes 17Z-20Z. The excellent model agreement continues with the 18Z NAM nest and other hourly high-resolution solutions staying in line with previous guidance. Thus, continued high confidence exists with frontal timing. Brief restrictions can't be ruled out, but VFR should prevail. Following the wind shift, sustained winds are expected to increase to 15-20 kts with gusts up to around 30 kts (slightly lower around CHO).

VFR conditions and gusty W/NW flow should prevail Sunday into Monday. The wind should weaken Tuesday as high pressure builds.

MARINE. Southerly flow is forecast to gradually increase tonight as a strong cold front approaches from the west. A few gusts to near gale force can't be ruled out Saturday, particularly with any line or lines of showers and isolated thunderstorms that form along the front as it crosses during the afternoon. However, the prevailing wind appears it may remain just below gale force most of the time (guidance over the last 24 hours has trended subtly weaker with the wind field by a few knots and a pinch lower with the pressure rises by 1-2 mb). Regardless, the wind may shift and begin gusting rather abruptly leading to hazardous conditions over the area waterways. NW flow behind the front likely remains gusty Sunday into Monday. Small Craft Advisories will likely be needed through at least Monday night. Winds should gradually diminish thereafter with a return of sub-SCA conditions expected by Tuesday afternoon.

TIDES/COASTAL FLOODING. Southerly flow ahead of the next cold front Saturday will result in rising tide levels. With anomalies this evening around or just above 1 foot, tonight's high tide (which is astronomically higher of the two) will be close to flooding thresholds at sensitive locations. Have issued an advisory at Annapolis where confidence is highest, but will monitor Straits Point and DC SW Waterfront. Uncertainty exists about how quickly anomalies can rise further Saturday before the winds switch to northwest behind the front and levels start to lower. Minor flooding remains possible Saturday at a few locations.

LWX WATCHES/WARNINGS/ADVISORIES. DC . None. MD . Coastal Flood Advisory until 6 AM EDT Saturday for MDZ014. VA . None. WV . None. MARINE . Small Craft Advisory until 6 AM EDT Sunday for ANZ530>534-537- 539>543. Small Craft Advisory from 6 AM Saturday to 6 AM EDT Sunday for ANZ538. Small Craft Advisory from 6 AM Saturday to 2 AM EDT Sunday for ANZ535-536.

SYNOPSIS . BRO/DHOF NEAR TERM . BRO/DHOF SHORT TERM . DHOF LONG TERM . JMG AVIATION . BRO/DHOF/JMG MARINE . BRO/DHOF/JMG TIDES/COASTAL FLOODING . ADS


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 63 mi56 min S 5.1G6 72°F 72°F1011.2 hPa
BLTM2 - 8574680 - Baltimore, MD 67 mi56 min SSW 1.9G2.9 72°F 73°F1011.1 hPa
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 71 mi56 min SSW 5.1G6 72°F 1011.4 hPa

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Hagerstown, Washington County Regional Airport, MD9 mi33 minSSE 610.00 miFair71°F64°F79%1011.3 hPa
Eastern WV Regional Airport/Shepherd Field, WV17 mi33 minN 010.00 miFair66°F63°F90%1010 hPa
Frederick Municipal Airport, MD24 mi31 minN 07.00 miFair70°F64°F83%1011.5 hPa

Link to 5 minute data for KHGR

Wind History from HGR (wind in knots)
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Last 24hrE50S6SE4SE40SE3SE5SE4S4SW344S5SW4S8S10S9S10S9S11S7S7S6
1 day agoNW30000000E30W30NW6N74NW50W3W3SW30000
2 days ago0E4E3E3000000SW4SW30SW43S30S4S40NE3E300

Tide / Current Tables for Chain Bridge, D.C.
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Chain Bridge
Click for Map
Fri -- 01:54 AM EDT     Moonset
Fri -- 04:47 AM EDT     3.11 feet High Tide
Fri -- 07:18 AM EDT     Sunrise
Fri -- 11:49 AM EDT     0.33 feet Low Tide
Fri -- 04:32 PM EDT     Moonrise
Fri -- 05:28 PM EDT     2.88 feet High Tide
Fri -- 06:29 PM EDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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Tide / Current Tables for Chain Bridge, one mile below, D.C.
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Chain Bridge
Click for Map
Fri -- 01:54 AM EDT     Moonset
Fri -- 04:42 AM EDT     3.11 feet High Tide
Fri -- 07:18 AM EDT     Sunrise
Fri -- 11:44 AM EDT     0.33 feet Low Tide
Fri -- 04:32 PM EDT     Moonrise
Fri -- 05:23 PM EDT     2.88 feet High Tide
Fri -- 06:29 PM EDT     Sunset
Fri -- 11:56 PM EDT     0.34 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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NOTE: This section has been updated as of 1/26/2021. If the image you are expecting is not showing, please let me know. You may use the EDIT function to update your location.
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