Sunday, December8, 2019
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Marine Weather and Tides
Grasonville, MD

Version 3.4
NOTICE
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.
6/2/2019. Many thanks to a user for reporting an error on one of the Edit pages. The switch to PHP 7.2 caused many pages that previously worked to quit working. I fixed many but I still depend on users to report ones I missed. Please report errors HERE or send an email to me at L-36.com. Allen

Sunrise 7:08AMSunset 4:43PM Sunday December 8, 2019 12:48 AM EST (05:48 UTC) Moonrise 2:48PMMoonset 3:20AM Illumination 86% 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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ANZ540 Eastern Bay- 937 Pm Est Sat Dec 7 2019
Rest of tonight..E winds 5 kt. Waves less than 1 ft.
Sun..S winds 5 to 10 kt. Waves 1 ft.
Sun night..S winds 5 to 10 kt. Waves 1 ft or less. A chance of rain or drizzle.
Mon..S winds 5 to 10 kt. Waves 1 ft. Rain.
Mon night..SW winds 10 to 15 kt with gusts to 20 kt. Waves 2 ft. Showers likely.
Tue..SW winds 10 to 15 kt. Waves 1 to 2 ft. Showers likely.
Tue night..NW winds 10 kt. Waves 1 ft. Showers.
Wed..NW winds 10 to 15 kt. Waves 1 ft. A chance of showers through the day.
Thu..NE winds 5 to 10 kt. Waves 1 ft.
ANZ500 937 Pm Est Sat Dec 7 2019
Synopsis for the tidal potomac and md portion of the chesapeake bay.. High pressure over ohio will build across pennsylvania and northern maryland tonight, then shift offshore of new jersey on Sunday. Low pressure will develop over the central united states and lift into the great lakes Sunday into Monday. A warm front developing east of this area of low pressure over the carolinas is expected to lift northward across the mid-atlantic on Monday. The aforementioned low will drag its trailing cold front through the region Tuesday into Wednesday. Small craft advisories become increasingly likely Monday night through Wednesday.


7 Day Forecast for Marine Location Near Grasonville, MD
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location: 38.88, -76.25     debug


Area Discussion for - Philadelphia/Mount Holly, PA
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FXUS61 KPHI 080218 AFDPHI

Area Forecast Discussion National Weather Service Mount Holly NJ 918 PM EST Sat Dec 7 2019

SYNOPSIS. High pressure will continue settling into the region tonight then moves offshore on Sunday. A warm front will lift north across the area on Monday ahead of the next low pressure system impacting the region through mid-week. A cold front will pass through late Tuesday then strong high pressure will build into the northeastern US through Thursday. Low pressure will return into next weekend.

NEAR TERM /UNTIL 6 AM SUNDAY MORNING/. 930 pm update: Models continue to struggle with the cooling outside of the urban corridor. Made additional adjustments earlier to lower lows in these areas and to knock down hourly temperatures a couple more degrees. Forecast is still verifying too warm in general, but expect this to improve in the next couple hours as the rate of cooling slows.

630 pm update: Temperatures are a challenge early this evening, as the urban heat island is keeping things warmer than forecast in the Philly metro while the rural/valley locations are tanking quickly. Suspect there will be a few hours in which temperatures are much more variable than the grids depict, but I did make an effort to simulate this variability a bit more.

Previous discussion .

High pressure will be directly across the area tonight. Clear skies and cold temperatures are expected. Lows will be close to 10 across the far north and in the teens and low 20s elsewhere. Reduced the temps across the north sharply from earlier with the snow on the ground and near ideal radiational conditions expected. Readings for metro Philadelphia will be in the mid 20s. Winds will be light and variable.

SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/. The center of the high will be offshore by morning but it will remain in control of the weather thru the day. Sunny or mostly sunny skies are expected through the day. After a very cold morning, temperatures will rebound back to near normal readings by afternoon. Highs will range from the upper 30s/low 40s N/W to near 50 S/E and metro Philadelphia. Winds will increase from the SE to S at 5 to 10 mph by early afternoon then switch around to SW late.

LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/. A busy start to the extended forecast period as a strong surface low moves out of the plains and into the Great Lakes region. The first affects of this system will be the arrival of a warm front Sunday night from south to north. An elongated vorticity impulse along the front will likely drive an area of moderate rain northward along the coast Sunday night. Several vorticity impulses will move from southeast to northeast through the region Monday through early Wednesday, which will translate into several periods of enhanced lift and heavier rounds of rainfall. Forecast soundings suggest precip could begin as a mix of rain and snow across the higher elevations of the Southern Poconos and across Sussex County, NJ- maybe even into the Lehigh Valley as well into early Monday morning. No accumulations are expected though, and rising temperatures into the 50s Monday will lead to quickened melting of any snow.

Heading into Tuesday, a cold front is expected to move across the area into the evening. Rainfall rates will likely increase as the precipitation shield expands across central PA along the front. PW values will likely exceed 1.00 inches and approach 1.25-1.50 inches Monday-Tuesday, so there could be period of moderate to heavy rainfall at times. With the first round of rainfall Monday-Monday night, we could get around 1.00-1.25 inches, and with the second round of rainfall, we could get 0.50-0.75 inches. There is a chance for some poor drainage/nuisance type flooding in areas of heavier rainfall during Monday-Tuesday. The longer duration of the rain should preclude any major flood concerns beyond this, however. Storm total rainfall generally ranges from 1-2 inches.

The front may stall to an extent as it moves offshore. The EC is more centralized in this camp, forecasting one additional impulse to ride along the front Wednesday morning, which would linger rainfall. The GFS still under-rides the CAA behind the front, suggesting a more substantial sneaker snow event may unfold early Wednesday morning. Am not currently buying this completely, contrary to many of our wishes. Climatologically, it is tough to keep the moisture around behind the fropa in these types of systems. This may very well follow a similar pattern to the storm system before Thanksgiving with a quick hour of snow showers with little to now accumulation. There is also the chance a few isolated lake-effect streamers may make their way into the Poconos in the afternoon, but chances of this are not very high attm. Highs will be much cooler in the 30s and 40s Wednesday compared to the 50s and 60s on Monday and Tuesday.

On Thursday, strong 1040-1045 mb high pressure will be moving from the Great Lakes region toward the northeastern CONUS with strong zonal flow aloft. Cold air advection will be underway early, then the north to northwesterly winds will decrease throughout the day. High temps will struggle to climb into the 30s area wide. Otherwise mainly clear and dry conditions are expected with surface dewpoints likely in the single digits. Temps will fall quickly Thursday evening, but lows will depend on the proximity of the center of the high across New England. If it's farther away, winds will stay more elevated and temps would not be as cold. Nevertheless, temps will be on the order of 10 degrees below normal.

On Friday, the cold and dry airmass will be recovering with cold advection shut off, but temps will likely top out a few degrees below normal. The GFS is aggressive in amplifying a southern stream wave ejecting from the southwestern CONUS arriving along the East Coast Friday, however it certainly appears to be an outlier compared to other deterministic medium range guidance; I have discounted its validity and left sub-mentionable PoPs for this period. Clouds will be on the increase throughout the day though with longwave upper troughing developing across the central US.

The next big rain-making system will impact the region starting early Saturday as the aforementioned upper troughing propagates closer to the East Coast. Depending on how persistent the cold surface air remains entrenched, could certainly a period of wintry mix at the precip onset early Saturday, but confidence on this is low. Medium range guidance differs quite a bit on the exact timing of the precipitation, but precipitation does appear likely.

AVIATION /02Z SUNDAY THROUGH THURSDAY/. The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas.

Tonight . VFR with light/variable winds. High confidence.

Sunday . VFR with light/variable winds in the morning becoming southerly up to 10 kt during the afternoon. High confidence.

Outlook .

Sunday night . Conditions may lower to MVFR later in the overnight as a warm front lifts through the region. South-southeasterly winds from 5 to 10 knots. Moderate confidence.

Monday-Tuesday . An extended period of MVFR and IFR conditions likely as periods of rain move across the area. Southeast winds early Monday become southwest once a warm front lifts across the area Monday. Winds from 5 to 10 knots shift to the northwest behind a cold front later Tuesday into Tuesday night with a few gusts to 15 knots possible as this occurs. Moderate confidence.

Tuesday night-Wednesday . Rain or snow remains possible with MVFR or IFR conditions possible. IFR conditions to improve to VFR Wednesday afternoon. West to northwest winds become gusty to 20-25 knots on Wednesday. Westerly winds should drop below 15 knots Wednesday night. Moderate confidence.

MARINE. High pressure across the waters this evening will move to the east overnight. A return flow will develop behind the high on Sunday. Sub-SCA conditions are expected. Fair weather. Seas 2 to 3 ft tonight and Sunday. On Delaware Bay waves 1 to 2 ft at most.

Outlook .

Small Craft Advisory conditions will likely be developing throughout the day Monday with seas building up to 9 feet Monday night and winds gusting up to 30 kts on ocean waters. These conditions will persist through Tuesday before gradually diminishing Tuesday night.

On Wednesday, offshore winds will be in the 20-25 kts range with seas 4-5 feet. Small Craft Advisory conditions probable.

PHI WATCHES/WARNINGS/ADVISORIES. PA . None. NJ . None. DE . None. MD . None. MARINE . None.

Synopsis . Staarmann Near Term . CMS/O'Hara Short Term . O'Hara Long Term . Davis/Staarmann Aviation . CMS/Davis Marine . O'Hara/Staarmann


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
TPLM2 - Thomas Point, MD 10 mi49 min E 4.1 G 5.1 39°F 45°F1033.7 hPa (+0.9)25°F
CPVM2 11 mi55 min 38°F 30°F
44063 - Annapolis 12 mi31 min Calm G 1.9 39°F 45°F1033.4 hPa
APAM2 - 8575512 - Annapolis, MD 14 mi55 min 33°F 1032.3 hPa
CA2 - 8571892 - Cambridge, MD 23 mi55 min NE 5.1 G 5.1 36°F 43°F1032.7 hPa
TCBM2 - 8573364 - Tolchester Beach, MD 23 mi55 min E 1.9 G 1.9 29°F 44°F1033 hPa
44062 - Gooses Reef, MD 24 mi31 min E 9.7 G 9.7 40°F 1033.5 hPa
BSLM2 - Chesapeake Bay, MD 25 mi139 min Calm 28°F 1032 hPa25°F
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 28 mi55 min NNE 2.9 G 2.9 36°F 1033 hPa
BLTM2 - 8574680 - Baltimore, MD 32 mi55 min Calm G 1.9 36°F 49°F1032.5 hPa
SLIM2 - 8577330 - Solomons Island, MD 40 mi55 min N 4.1 G 5.1 36°F 47°F1032.4 hPa
WASD2 - 8594900 - Washington, DC 41 mi55 min Calm G 0 34°F 44°F1033.1 hPa
BISM2 - 8571421 - Bishops Head, MD 47 mi55 min ENE 8 G 9.9 37°F 43°F1032.8 hPa

Wind History for Cambridge, MD
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Bay Bridge Field, MD8 mi54 minno data10.00 miFair28°F24°F86%1032.8 hPa
Easton / Newman Field, MD11 mi3.1 hrsN 010.00 miClear30°F23°F75%1033.5 hPa
Annapolis, United States Naval Academy, MD14 mi1.9 hrsN 010.00 miFair33°F27°F78%1032.8 hPa

Link to 5 minute data for KW29

Wind History from W29 (wind in knots)
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N7N6CalmN3N7N6N7N8N9N7N6NE3N3CalmCalmN5Calm----Calm
1 day agoCalmCalmS4S3CalmS4S4S7S11S11
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Tide / Current Tables for Claiborne, Eastern Bay, Maryland
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Claiborne
Click for Map
Sun -- 12:31 AM EST     0.92 feet High Tide
Sun -- 03:20 AM EST     Moonset
Sun -- 07:04 AM EST     -0.09 feet Low Tide
Sun -- 07:10 AM EST     Sunrise
Sun -- 01:37 PM EST     1.17 feet High Tide
Sun -- 02:48 PM EST     Moonrise
Sun -- 04:43 PM EST     Sunset
Sun -- 08:20 PM EST     0.26 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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0.90.90.80.60.40.1-0-0.1-00.20.40.711.11.21.10.90.70.50.30.30.30.40.6

Tide / Current Tables for Baltimore Harbor Approach, Maryland Current
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Baltimore Harbor Approach
Click for Map
Sun -- 02:18 AM EST     0.45 knots Max Flood
Sun -- 03:21 AM EST     Moonset
Sun -- 04:49 AM EST     -0.00 knots Slack
Sun -- 07:11 AM EST     Sunrise
Sun -- 08:03 AM EST     -0.68 knots Max Ebb
Sun -- 10:57 AM EST     0.00 knots Slack
Sun -- 02:33 PM EST     1.01 knots Max Flood
Sun -- 02:48 PM EST     Moonrise
Sun -- 04:42 PM EST     Sunset
Sun -- 06:04 PM EST     -0.00 knots Slack
Sun -- 09:13 PM EST     -0.84 knots Max Ebb
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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0.10.30.40.40.2-0.1-0.4-0.6-0.7-0.6-0.300.40.8110.80.50-0.4-0.7-0.8-0.8-0.6

Weather Map
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wmap_A
GEOS Local Image of Mid-Atlantic    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.
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Other links: Northern Pacific     Contential US     Full GOES-East
Wind Forecast for Philadelphia/Mount Holly, PA (0,6,7,8)
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Ground Weather Radar Station Dover AFB, DE
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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 numerious 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.