Thursday, April22, 2021
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Marine Weather and Tides
St. James, MD

Version 3.4
NOTICE
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 6:21AMSunset 7:57PM Thursday April 22, 2021 10:53 PM EDT (02:53 UTC) Moonrise 1:44PMMoonset 3:12AM Illumination 85% Phase: Waxing Gibbous; Moon at 11 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- 1039 Pm Edt Thu Apr 22 2021
Rest of tonight..W winds 5 to 10 kt. Waves 1 ft.
Fri..W winds 5 to 10 kt with gusts to 20 kt. Waves 1 ft.
Fri night..SW winds 5 to 10 kt. Waves 1 ft.
Sat..S winds 5 to 10 kt. Waves 1 ft. Rain likely.
Sat night..S winds 5 to 10 kt. Waves 1 ft. Rain.
Sun..NW winds 5 to 10 kt...increasing to 15 kt in the afternoon. Gusts up to 25 kt. Waves 1 ft.
Sun night..NW winds 10 to 15 kt with gusts to 25 kt. Waves 1 ft.
Mon..N winds 5 to 10 kt...becoming S after midnight. Waves 1 ft.
Tue..S winds 5 to 10 kt. Waves 1 ft.
ANZ500 1039 Pm Edt Thu Apr 22 2021
Synopsis for the tidal potomac and md portion of the chesapeake bay.. High pressure will settle over the carolinas through Friday. Low pressure will pass through central or southern virginia and maryland this weekend, when small craft advisories will likely be needed.


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 230046 AFDLWX

Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 846 PM EDT Thu Apr 22 2021

SYNOPSIS. High pressure will settle over the Carolinas through Friday. Low pressure will pass through central or southern Virginia and Maryland this weekend, then high pressure will return early next week.

NEAR TERM /THROUGH FRIDAY/.

The persistent wind gusts of 25 to 30 knots that were ongoing have subsided as the sun has set. Winds continue out of west to northwest with skies slowly clearing. As skies clear and winds become light, decoupling will allow to temperatures to drop down near to below freezing as dewpoints hover in the 20s. Freeze warnings and frost advisories are in effect for most of the region.

.Previous Discussion

A deep upper-level low is spinning over northern New England with a trailing trough axis pivoting over the Middle Atlantic. A weak surface trough is evident near I-95 marked by little more than a drop in dew point temperatures.

Northwesterly breezes should subside rather quickly this evening with the onset of nocturnal cooling and as the better pressure gradient begins to lift away. With the departing trough, expect clearing conditions overnight as well. This is expected to result in widespread temperatures near or a few degrees below freezing and areas of frost overnight.

SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/. High pressure will settle over the Carolinas Friday before moving offshore Friday night. Temperatures will moderate rather noticeably with highs well into the 60s expected.

Clouds will begin to increase late Friday night well ahead of low pressure approaching from the central US. This should keep temperatures milder compared to previous nights with no additional frost or freeze concerns anticipated.

Low pressure is expected to track near or just south of the area over the weekend bringing a soaking rain. There remains some uncertainty as to the exact rainfall amounts, but a general average of half to one inch looks most likely Saturday afternoon and night. Slightly higher amounts could result in some minor flooding issues, but that threat should be mitigated due to the recent dry weather. A slightly further north track of the low would draw some marginally unstable air and the threat for a few gusty thunderstorms into southern parts of the CWA, but the threat for that looks low as well at the moment.

LONG TERM /SUNDAY THROUGH THURSDAY/. Low pressure will exit the region Sunday morning which may result in some residual damp conditions during the early morning hours. However, high pressure will quickly build back into the region. Therefore, do expect conditions to quickly dry out by the midday. Winds will also become quite gusty Sunday afternoon as a result of a tightening pressure gradient.

Thereafter, the high will gradually slide southward from the Great Lakes region which will keep the region dry through midweek. As the high migrates further south, a warming trend will ensue as a result of southerly flow. Temperatures will begin to gradually warm during this time as we will likely see summer-like temperatures by Wednesday.

AVIATION /01Z FRIDAY THROUGH TUESDAY/. W/NW gusts of 25 to 30 kt should diminish quickly this eve, w/ additional gusts of 20 to 25 kt possible for northern terminals Friday. Low pressure will approach Saturday bringing rain and sub-VFR conditions as well as a more southerly wind.

CIG/VSBY restrictions are likely to persist early Sunday morning. However do expect conditions to quickly return to VFR by midday Sunday. Gusty NW winds will develop by Sunday afternoon as a result of a tightening gradient. High pressure will remain in control throughout much of next week, resulting in continued VFR conditions.

MARINE. West to northwest wind gusts should diminish steadily overnight, though another uptick is possible Friday. The Small Craft Advisory may need to be extended/expanded as a result.

Low pressure will approach Saturday with rain arriving later in the day. The wind will turn more southerly ahead of low pressure, and could become gusty over the lower tidal Potomac River and middle portion of the Chesapeake Bay.

SCA to perhaps Gale conditions are likely Sunday as a result of a tightening gradient between the departing low offshore and high pressure building back into the region. Sub-SCA conditions are likely to persist throughout the remainder of next week as high pressure regains control.

FIRE WEATHER. Min RH of 25-35% and wind gusts of 15-25 MPH are possible Friday afternoon. Despite recent green-up, 10-hr fuel moistures are running 7-12%. This may aid in the potential for rapid fire spread during this time. A soaking rain should bring that threat to a quick end over the weekend.

LWX WATCHES/WARNINGS/ADVISORIES. DC . Frost Advisory from 2 AM to 9 AM EDT Friday for DCZ001. MD . Freeze Warning from 2 AM to 9 AM EDT Friday for MDZ003>006- 503>507. Frost Advisory from 2 AM to 9 AM EDT Friday for MDZ008-011-013- 014-016>018-508. VA . Freeze Warning from 2 AM to 9 AM EDT Friday for VAZ025>031- 036>040-050>053-055-056-501-502-505>508. Frost Advisory from 2 AM to 9 AM EDT Friday for VAZ054-057. WV . Freeze Warning from 2 AM to 9 AM EDT Friday for WVZ051>053. MARINE . Small Craft Advisory until 6 AM EDT Friday for ANZ530>534- 536>543. Small Craft Advisory until midnight EDT tonight for ANZ535.

SYNOPSIS . DHOF NEAR TERM . DHOF/JMG SHORT TERM . DHOF LONG TERM . MSS AVIATION . MSS/DHOF/JMG MARINE . MSS/DHOF FIRE WEATHER .


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 63 mi54 min WNW 2.9 G 4.1 49°F 59°F1018.7 hPa (+2.1)
BLTM2 - 8574680 - Baltimore, MD 67 mi54 min W 1 G 4.1 47°F 55°F1017.6 hPa (+2.1)
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 71 mi54 min W 8 G 8.9 47°F 1018 hPa (+2.4)

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Hagerstown, Washington County Regional Airport, MD9 mi61 minWNW 510.00 miFair40°F20°F45%1018.9 hPa
Eastern WV Regional Airport/Shepherd Field, WV17 mi61 minWNW 810.00 miMostly Cloudy44°F17°F34%1018.1 hPa
Frederick Municipal Airport, MD24 mi59 minWNW 410.00 miOvercast43°F21°F42%1017.9 hPa

Link to 5 minute data for KHGR

Wind History from HGR (wind in knots)
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1 day agoS6S5S6S6S6S5S9S7S8S7S8W17
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2 days agoS6S7S7S5S6S7S7S6SE5S5SW6W9SW6W8NW4S10
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Tide / Current Tables for Chain Bridge, D.C.
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Chain Bridge
Click for Map
Thu -- 04:07 AM EDT     Moonset
Thu -- 05:07 AM EDT     2.97 feet High Tide
Thu -- 06:21 AM EDT     Sunrise
Thu -- 11:31 AM EDT     0.57 feet Low Tide
Thu -- 02:42 PM EDT     Moonrise
Thu -- 05:22 PM EDT     3.09 feet High Tide
Thu -- 07:52 PM EDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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0.611.72.42.832.82.41.91.30.80.60.60.91.52.32.83.132.72.11.510.6

Tide / Current Tables for Chain Bridge, one mile below, D.C.
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Chain Bridge
Click for Map
Thu -- 04:07 AM EDT     Moonset
Thu -- 05:02 AM EDT     2.97 feet High Tide
Thu -- 06:21 AM EDT     Sunrise
Thu -- 11:26 AM EDT     0.57 feet Low Tide
Thu -- 02:42 PM EDT     Moonrise
Thu -- 05:17 PM EDT     3.09 feet High Tide
Thu -- 07:52 PM EDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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0.611.82.42.832.82.41.81.20.80.60.60.91.62.32.93.132.62.11.510.6

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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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