Saturday, September19, 2020
Privacy Policy
L-36.com

Marine Weather and Tides
Williamsport, MD

Version 3.4
NOTICE
8/26/2020 The 7 day forecast is taking about 5 seconds to load but it will eventually load. NOAA is still working on it.
8/18/2020 NOAA continues to have trouble. Wind guest will occasionally be left off graphs. I am working with NOAA to resolve the issue.
12/16/2019 NOAA is having trouble with requests that include wind gusts. I am posting graphs without wind gusts until it gets fixed.
10/9/2019 Updated the Marine Zones.
9/4/2019 Fixed the weather maps due to NOAA moving them.
7/25/2019 New feature in the Airports section gives a link to 5 minute updates for data reports.

Sunrise 6:55AMSunset 7:13PM Saturday September 19, 2020 2:36 PM EDT (18:36 UTC) Moonrise 8:22AMMoonset 7:54PM Illumination 6% Phase: Waxing Crescent; Moon at 2 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
    EDIT      (on/off)   Help
ANZ535 Tidal Potomac From Key Bridge To Indian Head- 136 Pm Edt Sat Sep 19 2020
This afternoon..NE winds 10 kt. Waves 1 ft.
Tonight..N winds around 5 kt. Waves 1 ft.
Sun..NE winds 5 to 10 kt. Waves 1 ft.
Sun night..NE winds around 5 kt. Waves 1 ft.
Mon..NE winds 5 kt. Waves less than 1 ft.
Mon night..NW winds around 5 kt. Waves 1 ft.
Tue..W winds around 5 kt. Waves 1 ft.
Wed..W winds around 5 kt. Waves 1 ft.
ANZ500 136 Pm Edt Sat Sep 19 2020
Synopsis for the tidal potomac and md portion of the chesapeake bay.. Canadian high pressure will build from the great lakes toward the northeast and middle atlantic through early next week as hurricane teddy swirls northward well offshore. Small craft advisories may be needed Sunday into Monday.


7 Day Forecast for Marine Location Near Williamsport, MD
   Hourly   EDIT   Help
location: 39.58, -77.81     debug


Area Discussion for - Baltimore, MD/Washington
      (on/off)   Help   NOTE: mouseover dotted underlined text for definition
FXUS61 KLWX 191417 AFDLWX

Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 1017 AM EDT Sat Sep 19 2020

SYNOPSIS. Canadian high pressure will build from the Great Lakes into the Northeast and Middle Atlantic through the weekend, then gradually shift offshore during the first half of next week.

NEAR TERM /THROUGH TONIGHT/. Latest surface analysis shows large 1030 hPa Canadian high pressure centered over the Great Lakes. This high will continue to bring dry conditions across the region this afternoon and tonight. An upper level jet located extending from AL-GA into the Mid-Atlantic region over SE VA has a streak of cirrus associated with it this morning that will continue affecting our southern zones through the afternoon before diminishing by this evening as the jet moves out to sea. Otherwise expect sunny and notably bluer skies the remainder of the area this afternoon as yesterday's cold front pushed out the elevated smoke layer that was lingering across the region.

The 12Z IAD raob showed NErly 25-30 kt winds 1-2 kft and latest model trends show surface pressure gradient will continue tight through mid-afternoon but then begin to slacken toward late afternoon. So a breezy day remainder of this morning most areas especially higher elevations and east of the Blue Ridge.

Temperatures today will be a good 10 to even 15 degF below seasonable normals . readings more typical of mid-October. Highs this afternoon in the metro DC/Balt areas in the mid-60s.

Tonight expect a chilly night with temperatures west of the Blue Ridge generally mid/upper 30 . where we currently are forecasting patchy frost . while low/mid 40s will occur east of the Blue Ridge . except warmer readings still in the 50s near our marine/coastal areas. Will evaluate need for a any frost or freeze headlines for tonight after the new 12Z guidance is in.

SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/. Sunshine and cooler than average temperatures will continue Sunday through Monday night. High pressure will be reinforced by high pressure as a mid-level ridge builds in from the west throughout the period.

LONG TERM /TUESDAY THROUGH FRIDAY/. A relatively quiet pattern will reign through most of the long term. At the start, northerly flow aloft will dominate as a closed low sits over the western Atlantic and a ridge is positioned over the south- central US. This will result in a cool high pressure centered over the southern Appalachians and Teddy well to our northeast, with a northerly surface flow as well.

By Wednesday, the closed upper low will open up and lift northeast, with the upper ridge migrating eastward. This will allow Teddy to retreat northeast further away into the Canadian Maritimes with surface high pressure to our south, allowing a milder flow of air to reach us.

By Thursday, the upper ridge will be over our region, but weakening and transient by this point as another upper shortwave approaches from the northwest. At the surface, this will mean we have a cold front approaching from the northwest, but a mild air mass will remain in place.

On Friday, the aforementioned front and upper level trough may be reaching our region, but guidance is divergent as to whether there is any precipitation with this front.

Before Friday, with no features of significance actually crossing our region, the chance of precip will be near zero, but temperatures will change noticeably, with below normal readings Monday rising to slightly above normal by Thursday. With the cold front nearby Friday, temperatures may start to decline slightly, but not expecting a big change yet.

AVIATION /14Z SATURDAY THROUGH WEDNESDAY/. No restrictions expected through early next week . with VFR conditions prevailing at all terminals. Winds this afternoon will be gust from the NE but should slacken 20-22Z.

No restrictions are expected Tuesday and Wednesday as high pressure should dominate with northwesterly winds and clear to partly cloudy skies. Little if any fog is anticipated as well.

MARINE. Small craft advisories are in effect now through 6PM . and will need to evaluate possible extension of SCAs in the lower Potomac and lower Chesapeake Bay beyond 6PM possibly into early evening. Otherwise, no marine hazards tonight and Sunday morning. Small craft possible Sunday afternoon. No marine hazards expected Sunday night through Monday night.

Small Craft Advisory conditions are possible Tuesday as surface high pressure to the north and west interacts with Teddy as it passes well to our east and northeast. Winds likely abate Wednesday.

TIDES/COASTAL FLOODING. Tides generally running a bit below normal with the northerly push of winds across the region . as winds slacken levels will start to return later tonight through the day Sunday. Tide levels in the Chesapeake and Tidal Potomac could reach advisory criteria later Sunday into Sunday evening.

LWX WATCHES/WARNINGS/ADVISORIES. DC . None. MD . None. VA . None. WV . None. MARINE . Small Craft Advisory until 6 PM EDT this evening for ANZ530>543.

SYNOPSIS . SMZ NEAR TERM . SMZ SHORT TERM . KLW LONG TERM . RCM/SMZ AVIATION . RCM/SMZ MARINE . RCM/SMZ TIDES/COASTAL FLOODING . SMZ


Weather Reporting Stations
   EDIT       (on/off)   Help   NOTE: Click on distance to see the station location on a map
Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 64 mi48 min NNE 6 G 8.9 73°F1027.7 hPa
BLTM2 - 8574680 - Baltimore, MD 69 mi48 min E 8.9 G 12 76°F1027.1 hPa
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 72 mi48 min NNE 7 G 11 1027.4 hPa

Wind History for Washington, DC
(wind in knots)    EDIT      (on/off)   Help
2
PM
3
PM
4
PM
5
PM
6
PM
7
PM
8
PM
9
PM
10
PM
11
PM
12
AM
1
AM
2
AM
3
AM
4
AM
5
AM
6
AM
7
AM
8
AM
9
AM
10
AM
11
AM
12
PM
1
PM
Last
24hr
N5
G10
N3
G11
N6
G12
N5
G11
N4
G8
N5
G8
N4
G9
N6
G11
N4
G10
N7
G12
N5
G12
N4
G9
N7
G11
N7
G12
N5
G11
N4
G11
N5
G13
N6
NE4
G10
N6
G12
NE4
G7
N4
G10
N4
G10
NE7
1 day
ago
S3
S4
S4
SE1
--
--
SE2
--
--
E2
--
--
N3
N3
E1
G4
NE2
N6
G9
N4
G8
N5
G10
N4
G8
N3
G11
N8
G11
N4
G10
N8
G11
2 days
ago
S7
G11
S7
S8
S5
S6
SE5
SE2
G5
SE3
SE3
W1
S5
S2
SW2
W3
W1
--
--
NW1
W1
W1
--
SW1
S1
S2

Airport Reports
    EDIT      (on/off)   Help   Click EDIT to display multiple airports. Follow links for more data.
AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Hagerstown, Washington County Regional Airport, MD10 mi43 minVar 510.00 miFair62°F26°F25%1029 hPa
Eastern WV Regional Airport/Shepherd Field, WV15 mi43 minENE 610.00 miFair62°F28°F28%1027.8 hPa

Link to 5 minute data for KHGR

Wind History from HGR (wind in knots)
3
PM
4
PM
5
PM
6
PM
7
PM
8
PM
9
PM
10
PM
11
PM
12
AM
1
AM
2
AM
3
AM
4
AM
5
AM
6
AM
7
AM
8
AM
9
AM
10
AM
11
AM
12
PM
1
PM
2
PM
Last 24hrN11N12N15
G20
N14NW10N11N7N7NE10NE13
G19
N10
G18
N7N5NW5N6N3N6N6N7N8NE11N6NE85
1 day agoCalmCalmSE3CalmCalmCalmCalmCalmNW3N4CalmCalmNW5NW6NW6N6NW7N6N6N9
G18
N13N15
G21
N14N10
G21
2 days agoSW9SW6SE10S12S8S6S4S6S5S3S3CalmCalmCalmSE4CalmCalmCalmCalmCalmCalmCalmCalmW4

Tide / Current Tables for Chain Bridge, D.C.
   EDIT   Weekend mode (on/off)   (on/off)   Help   One Week of Data
Chain Bridge
Click for Map
Sat -- 05:06 AM EDT     0.02 feet Low Tide
Sat -- 06:53 AM EDT     Sunrise
Sat -- 09:19 AM EDT     Moonrise
Sat -- 10:36 AM EDT     3.59 feet High Tide
Sat -- 05:19 PM EDT     -0.06 feet Low Tide
Sat -- 07:09 PM EDT     Sunset
Sat -- 08:51 PM EDT     Moonset
Sat -- 10:58 PM EDT     3.81 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

12
am
1
am
2
am
3
am
4
am
5
am
6
am
7
am
8
am
9
am
10
am
11
am
12
pm
1
pm
2
pm
3
pm
4
pm
5
pm
6
pm
7
pm
8
pm
9
pm
10
pm
11
pm
32.21.40.80.300.212.133.53.53.12.31.50.80.3-00.10.71.82.93.63.8

Tide / Current Tables for Chain Bridge, one mile below, D.C.
   EDIT      (on/off)   Help   One Week of Data
Chain Bridge
Click for Map
Sat -- 05:02 AM EDT     0.02 feet Low Tide
Sat -- 06:53 AM EDT     Sunrise
Sat -- 09:19 AM EDT     Moonrise
Sat -- 10:31 AM EDT     3.59 feet High Tide
Sat -- 05:14 PM EDT     -0.06 feet Low Tide
Sat -- 07:09 PM EDT     Sunset
Sat -- 08:51 PM EDT     Moonset
Sat -- 10:53 PM EDT     3.81 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

12
am
1
am
2
am
3
am
4
am
5
am
6
am
7
am
8
am
9
am
10
am
11
am
12
pm
1
pm
2
pm
3
pm
4
pm
5
pm
6
pm
7
pm
8
pm
9
pm
10
pm
11
pm
2.92.11.40.70.200.31.12.23.13.53.532.31.50.80.2-00.10.81.933.63.8

Weather Map
       (on/off)   Help Weather Map
wmap_A
GEOS Local Image of    EDIT
NOTE: East coast views moved to GEOS-16. They are experimental and not well supported by NOAA so they may not be correct so be warned. This change required redoing a large amount of the GOES code. If the image you are expecting is not showing, please let me know. You may need to use the EDIT function to update your location.
Link to Loop

Other links: Northern Pacific     Contential US     Full GOES-East
Ground Weather Radar Station Sterling, VA
   (on/off)   Help
weather_mapweather_map weather_map


Cookie Policy:
This website uses cookies to save your settings. No personal information is saved. I do not collect statistics on your visit. You can disable cookies in your browser if you like but it is not recommended for this site. I do not sell cookies. Go to a bakery for that. In fact I do not sell anything. To disable cookies from L-36.com, please refer to the Help button in your browser.
Privacy Policy:
I do not sell or share any user data or anything else for that matter. The only personal information I save is in the site log which has a line for each page view which includes the IP address your browser sends in the header as well as which page you requested. I use this to block hackers and other bad actors. I do not use this raw data to create profiles on users. I periodically delete the log files. Google supplies the ads on this site. Because I do not track who you are, I cannot customize how these ads are served. They may be personalized to improve the ad experience. If you do not want personalized ads, please adjust the settings on the Google site HERE.
. NOTE: The best I can determine, this site is not subject to CCPA but I am doing my best to comply anyway. Disclaimer:
The information on this web site has not been checked for accuracy. It is for entertainment purposes only and should be independently verified before using for any other reason. There are five sources. 1) Documents and manuals from a variety of sources. These have not been checked for accuracy and in many cases have not even been read by anyone associated with L-36.com. I have no idea of they are useful or accurate, I leave that to the reader. 2) Articles others have written and submitted. If you have questions on these, please contact the author. 3) Articles that represent my personal opinions. These are intended to promote thought and for entertainment. These are not intended to be fact, they are my opinions. 4) Small programs that generate result presented on a web page. Like any computer program, these may and in some cases do have errors. Almost all of these also make simplifying assumptions so they are not totally accurate even if there are no errors. Please verify all results. 5) Weather information is from numerous of sources and is presented automatically. It is not checked for accuracy either by anyone at L-36.com or by the source which is typically the US Government. See the NOAA web site for their disclaimer. Finally, tide and current data on this site is from 2007 and 2008 data bases, which may contain even older data. Changes in harbors due to building or dredging change tides and currents and for that reason many of the locations presented are no longer supported by newer data bases. For example, there is very little tidal current data in newer data bases so current data is likely wrong to some extent. This data is NOT FOR NAVIGATION. See the XTide disclaimer for details. In addition, tide and current are influenced by storms, river flow, and other factors beyond the ability of any predictive program.