Monday, September27, 2021
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Marine Weather and Tides
Frederick, 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 7:01AMSunset 6:59PM Monday September 27, 2021 3:28 AM EDT (07:28 UTC) Moonrise 9:48PMMoonset 12:26PM Illumination 67% Phase: Waning Gibbous; Moon at 21 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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ANZ538 Patapsco River Including Baltimore Harbor- 136 Am Edt Mon Sep 27 2021
.small craft advisory in effect from this afternoon through this evening...
Overnight..W winds 10 kt. Waves 1 ft.
Mon..SW winds 5 to 10 kt. Waves 1 ft.
Mon night..SW winds 5 to 10 kt with gusts to 20 kt. Waves 1 ft.
Tue..W winds 5 to 10 kt. Waves 1 ft. A chance of showers and tstms.
Tue night..NW winds 5 to 10 kt. Waves 1 ft. A chance of showers and tstms.
Wed..N winds 5 to 10 kt. Waves 1 ft.
Wed night..N winds 5 to 10 kt. Waves 1 ft or less.
Thu..N winds 5 kt. Waves less than 1 ft.
Fri..N winds 5 kt. Waves less than 1 ft. Winds and waves higher and visibilities lower in and near tstms.
ANZ500 136 Am Edt Mon Sep 27 2021
Synopsis for the tidal potomac and md portion of the chesapeake bay.. High pressure will build overhead through tonight. The high will move offshore Monday before another cold front is poised to cross the waters late Tuesday. Canadian high pressure will build southward toward the waters through the end of the work week. Small craft advisories may be needed for portions of the waters Tuesday.


7 Day Forecast for Marine Location Near Frederick, MD
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location: 39.43, -77.41     debug


Area Discussion for - Baltimore, MD/Washington
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FXUS61 KLWX 270045 AFDLWX

Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 845 PM EDT Sun Sep 26 2021

SYNOPSIS. High pressure over the southeastern U.S. will be in control of our weather through Monday. A cold front will approach from the north Monday night and Tuesday before passing through Tuesday night. Canadian high pressure will build southward toward the region Wednesday through Saturday, bringing noticeably cooler conditions.

NEAR TERM /TONIGHT/. High pressure is centering itself over the southeastern U.S. this evening, extending a ridge northward across the Mid- Atlantic and into the Northeast. Locally, skies are clear and winds have gone light as the high nudges into the region and the gradient relaxes. This evenings upper air sounding sampled slight moistening throughout the column, coming in just above three quarters of an inch, indicative of warm air advection aloft commencing. Dry conditions overnight with the high in full control of the sensible weather elements. Lows tonight will settle to around normal levels for late September, generally in the low to middle 50s, a touch warmer in the city centers and cooler across the higher elevations. No updates needed to the current gridded forecast this evening.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/. For early Monday, winds will continue to progress more out of the SW. Could see an uptick in winds briefly as high pressure begins to suppress ahead of an impending cold front on Tuesday. Could see some gusts 10-15 mph across some areas and higher gusts over the waters during the day but will taper off over land areas fairly quickly. Another dry day expected with highs increasing into the upper 70s to near 80F for most areas.

Continued dry conditions into the early part of Tuesday with only a few showers across the Alleghenies before the afternoon. Shortwave energy associated with a deep upper level low over Canada will briefly move across the northern two thirds of the CWA late morning into the early afternoon, introducing the chance for a few showers. After that, a cold front attached to a surface low to the NE will drop down into the area and will bring increased chances for some showers and a few thunderstorms.

With increased temperatures and a moisture source with southerly flow for the period, instability looks to be favorable during the afternoon and evening hours on Tuesday. Guidance favors surface CAPE values of 1200+ j/kg during the early afternoon and evening hours as well as 25 to 30 knots of bulk shear. A few isolated strong to severe storms are possible with the most likely impacts being damaging winds and smaller hail. Main area of interest for this time frame would be along and east of the I-95 corridor, specifically during peak daytime heating. PoPs decrease overnight as the front moves offshore and Canadian high pressure influence is introduced.

LONG TERM /WEDNESDAY THROUGH SUNDAY/. Canadian high pressure will build toward the region from the north for Wednesday while the upper-level trough shifts closer toward the New England and Mid-Atlantic coast. This will provide a northerly flow that brings noticeably cooler and less humid conditions. Surface high pressure will remain nearby to the north, likely bringing below climo temperatures through the end of the week.

As of now, it is more likely to be dry with sunshine for Thursday and Friday as an upper-level low and its associated trough remain mostly to the north and east. However, a blocking pattern is expected and that adds to uncertainty in the forecast. If the closed upper-level low ends up a little farther southwest closer to our area, or another closed upper-level low develops farther southwest in the blocking pattern, then that will have a significant impact on the forecast. Will continue to monitor this, but the latest forecast leads toward drier solutions which is in line with the latest EPS and GEFS 500mb height ensemble means.

AVIATION /00Z MONDAY THROUGH FRIDAY/. High pressure atop the region tonight will promote light southwest to calm winds, clear skies, and VFR conditions.

During the day on Monday, expect gusts to pick back up briefly to around 10 to 15 knots but diminish fairly quickly by the late afternoon hours.

For Tuesday, SSW will continue but remain fairly light after morning rush hour. By Tuesday afternoon, cold front gets introduced to the region and may bring brief sub-VFR conditions for the terminals (CHO looks to have the least likely chance for restrictions). This will continue through the early overnight hours before the cold front passes and VFR conditions continue.

Canadian high pressure will mostly likely bring VFR conditions to the terminals for Wednesday and Thursday.

MARINE. Light southwest winds will dominate over the waters tonight as high pressure nudges into the region and the gradient relaxes. South southwest winds will turn gusty again Monday during the afternoon hours and persist through early Tuesday morning. Small Craft Advisories have been hoisted for this period with the expectation of winds 15 to 20 knots.

Winds will subside early Tuesday before a cold front passes through during the afternoon and evening hours with the possibility for thunderstorms over the waters, SMW's may be needed.

Canadian high pressure will build toward the waters Wednesday and Thursday, but it will remain centered to the north. Therefore, there may be enough of a gradient for north or northwest winds to gust near SCA criteria.

TIDES/COASTAL FLOODING. Anomalies have fallen some due to an offshore flow. However, a south southwest flow will increase Monday into Monday night, and this will cause elevated water levels again. Minor flooding is possible for sensitive areas around high tide Monday night (Annapolis and Washington DC), but confidence is low since the flow will be west of south.

LWX WATCHES/WARNINGS/ADVISORIES. DC . None. MD . None. VA . None. WV . None. MARINE . Small Craft Advisory from 2 PM Monday to midnight EDT Monday night for ANZ530>532-538>540. Small Craft Advisory from 5 PM Monday to 6 AM EDT Tuesday for ANZ533-534-537-541>543.

SYNOPSIS . BJL/BKF/ADM NEAR TERM . BKF SHORT TERM . ADM LONG TERM . BJL AVIATION . BJL/BKF/ADM MARINE . BJL/BKF/ADM TIDES/COASTAL FLOODING . BJL


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 44 mi59 min SSW 2.9 G 2.9 63°F 71°F1017.4 hPa
BLTM2 - 8574680 - Baltimore, MD 45 mi59 min WSW 1.9 G 2.9 63°F 76°F1016.9 hPa
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 49 mi59 min WSW 7 G 7 63°F 1017.2 hPa
FSNM2 49 mi65 min W 8.9 G 9.9 64°F 1017 hPa

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Frederick Municipal Airport, MD2 mi54 minS 310.00 miFair55°F50°F82%1017.9 hPa
Gaithersburg - Montgomery County Airport, MD22 mi33 minN 010.00 miFair52°F50°F93%1019.5 hPa

Link to 5 minute data for KFDK

Wind History from FDK (wind in knots)
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Last 24hrNW5CalmCalmCalmCalmCalmW5NW5NW9
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W5SE4SW4CalmS4SE3CalmS4SE4
1 day agoCalmCalmCalmCalmCalmCalmCalmCalmCalmW4SW5SW4W4W3W5CalmCalmCalmCalmCalmSW3W5W5NW5
2 days agoCalmCalmCalmCalmCalmCalmSW4W4NW7W5
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Tide / Current Tables for Chain Bridge, D.C.
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Chain Bridge
Click for Map
Mon -- 01:11 AM EDT     3.20 feet High Tide
Mon -- 07:00 AM EDT     Sunrise
Mon -- 08:15 AM EDT     0.69 feet Low Tide
Mon -- 01:23 PM EDT     Moonset
Mon -- 01:53 PM EDT     2.73 feet High Tide
Mon -- 06:57 PM EDT     Sunset
Mon -- 07:43 PM EDT     0.58 feet Low Tide
Mon -- 10:47 PM EDT     Moonrise
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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33.23.12.72.21.61.10.80.70.81.21.82.32.62.72.52.11.510.60.60.81.21.9

Tide / Current Tables for Chain Bridge, one mile below, D.C.
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Chain Bridge
Click for Map
Mon -- 01:06 AM EDT     3.20 feet High Tide
Mon -- 07:00 AM EDT     Sunrise
Mon -- 08:10 AM EDT     0.69 feet Low Tide
Mon -- 01:24 PM EDT     Moonset
Mon -- 01:48 PM EDT     2.73 feet High Tide
Mon -- 06:56 PM EDT     Sunset
Mon -- 07:38 PM EDT     0.58 feet Low Tide
Mon -- 10:47 PM EDT     Moonrise
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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33.23.12.72.11.61.10.80.70.81.21.82.42.72.72.521.50.90.60.60.81.32

Weather Map
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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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