Tuesday, March20, 2018 L-36.com

Marine Weather and Tides
Butler, MD

Version 3.4
What's New / NOTES
3/3/2018 - There is a new GOES Satellite for the east coast that required rewriting that part of the code. Please report any issues.
6/25/2017 - NOAA is having a major issue that impact the 7 day forecast load times. Many users are reporting problems. The issue has been reported.
5/23/2017 - Worked with NOAA again to speed up the 7 day forecast load times. Thanks to them for being responsive.

Sunrise 7:05AMSunset 7:19PM Tuesday March 20, 2018 4:06 AM EDT (08:06 UTC) Moonrise 8:08AMMoonset 9:42PM Illumination 12% Phase: Waxing Crescent; Moon at 3 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
ANZ530 Chesapeake Bay North Of Pooles Island- 132 Am Edt Tue Mar 20 2018
.small craft advisory in effect from 6 am edt this morning through Wednesday afternoon...
Overnight..NE winds 10 kt. Waves 1 ft. Rain.
Tue..NE winds 10 to 15 kt with gusts to 25 kt. Waves 2 ft. Sleet or rain and snow or freezing rain. Vsby 1 to 3 nm.
Tue night..NE winds 10 to 15 kt with gusts to 25 kt. Waves 2 ft. Snow or sleet. Vsby 1 to 3 nm.
Wed..N winds 10 to 15 kt with gusts to 25 kt. Waves 2 ft. Snow.
Wed night..NW winds 10 to 15 kt with gusts to 20 kt. Waves 1 ft. A chance of snow.
Thu..NW winds 10 to 15 kt with gusts to 20 kt. Waves 1 ft.
Thu night..NW winds 5 to 10 kt. Waves 1 ft.
Fri..NW winds 5 to 10 kt. Waves 1 ft.
Sat..SE winds 5 kt. Waves less than 1 ft. A chance of rain or snow through the night.
ANZ500 132 Am Edt Tue Mar 20 2018
Synopsis for the tidal potomac and md portion of the chesapeake bay.. Coastal low pressure will emerge and strengthen off the mid atlantic coast later this morning. Another low pressure system will develop off the carolina coast tonight, passing south of our region. High pressure will build in from the west Thursday and Friday. A small craft advisory will likely be needed for the waters Wednesday night through Thursday.

7 Day Forecast for Marine Location Near Butler, MD
   Hourly   EDIT   Help
location: 39.3, -76.17     debug

Area Discussion for - Philadelphia/Mount Holly, PA
      (on/off)   Help   NOTE: mouseover dotted underlined text for definition
Fxus61 kphi 200755
area forecast discussion
national weather service mount holly nj
355 am edt Tue mar 20 2018

A pair of low pressure systems today will merge into one large
coastal low by tomorrow. This low will lift northeast away from our
region Wednesday night into Thursday. High pressure builds in to
start the weekend. Another low pressure system may approach our
region early next week.

Near term until 6 pm this evening
Well, a rather challenging forecast as moisture moves up from the
south while rather dry low-level air (colder) is seeping southward.

As we start aloft, a strong short wave shifts eastward today from
the ohio valley and eventually starts to shear toward the east due
to an area of confluence in the flow to the northeast. Meanwhile,
another strong short wave sharpens an upper-level trough across the
tennessee valley by late today. At the surface, this translates to
low pressure developing off of the mid-atlantic coast while high
pressure centered near hudson bay canada wedges down into the mid-
atlantic region (cold air damming). So how does this impact our
sensible weather?
low-level warm air advection is forecast to occur into our region
above a shallow northeast flow. This will be augmented by increasing
easterly flow above the surface, combining to produce ample
isentropic lift which will be enhanced by short wave energy and
areas of 850-700 mb frontogenesis. A concern continues to be the
rather dry low-level air seeping southward from the canadian high
pressure system. This will tend to keep the wet-bulb temperature
lower especially across the central and northern areas, but deeper
drier air farther north will tend to halt the advancement of the
precipitation shield. The precipitation types are complicated due to
a warm layer in place for awhile, and some model guidance suggests
that a zone of sleet occurs. Some model soundings hint at freezing
rain, however a closer examination points to sleet due to a
shallower warm layer between about 800-850 mb. Freezing rain in late
march during the daytime hours is tough given marginal surface
temperatures. If more sleet were to fall, especially if heavy as
some guidance suggests, then accumulations would be more efficient.

There is quite a bit of uncertainty on this evolution, so definitely
look for updates during the course of the day. We opted to remove
the winter weather advisory for today, and start a winter storm
warning early this evening to simplify the messaging and will
discuss the mixed precipitation for today within the winter storm
warning product. Any snow and sleet accumulations should be on the
light enough side today, and we held off on any ice accumulation
from freezing rain until this evening as late march during the day
should limit any icing. It appears the northern edge of the
precipitation may struggle to get to and north of about i-78.

As low pressure develops off the mid-atlantic coast, the pressure
gradient tightens due to high pressure to the northwest. This along
with strengthening flow above the surface will result in a gusty
northeasterly wind with the highest gusts closer to the coast. This
looks to be focused across coastal southeastern new jersey to
southern delaware, therefore a wind advisory is in effect there for
today. For the hourly temperatures and high temperatures, we blended
in the 2-meter temperatures with continuity overall.

Short term 6 pm this evening through 6 am Wednesday
A rather complex setup continues to take shape tonight. A
significant upper-level trough that closes off will approach from
the central appalachians late tonight. This will maintain downstream
ascent, however there are two separate forcing areas one which
weakens and peels away to the northeast this evening. This should
allow the precipitation shield to weaken and perhaps becomes more
spotty for a time. Due to the precipitation intensity becoming
lighter and even hints at some drying aloft occurring for a time,
some light freezing rain drizzle and sleet should continue for parts
of the area although more light rain farther south and east.

As height falls arrive toward morning with the incoming closed low,
large scale ascent will start to increase with some uptick in the
frontogenesis. This will maintain surface low pressure development
off the mid-atlantic coast with a strong northeast wind continuing
especially closer to the coast. We ended the wind advisory at 6 pm,
as the gusty winds are included in the winter storm warning which
starts at 6 pm (most impacts though occur starting early Wednesday
morning). Given the idea of the column cooling from northwest to
southeast overnight, the precipitation type from any mixing should
start to transition over to snow toward daybreak for much of the
area. As mentioned, we started the winter storm warning at 6 pm to
cover any areas of light icing and mixed precipitation before things
really start to ramp up. This is a challenging forecast especially
with it being two phases with some weaker lift between them. Low
temperatures are a blend of continuity and model guidance.

Long term Wednesday through Monday
Pretty much all of the focus in the long term is on Wednesday
and Wednesday night.

Wednesday... Strong signal for trowal of the now merged coastal
low to be over our region. There is a very distinct theata e
ridge at 700 and 600 mb on the northwest side of the low in
nearly all of the operational models. Exactly where in our
region is uncertain, it could be over the i95 corridor or
further east over the coastal plains. This, along with the
placement of a band of frontogenesis is critical to determining
where the highest threat for mesoscale banding will be during
the day.

Hazards on Wednesday:
heavy wet snow especially under mesoscale banding. There is the
potential for a 6 to 12 hour period of very heavy snow with snow
rates of 2 to 3 inches at times. We expect to get a majority of
the overall snow accumulation in this period. As mentioned
above, there are still some questions as to where the highest
threat is, and thus, still some uncertainty with the snow
amounts. Given the temperature profiles, expect a very heavy wet
snow to be falling through this time as the snow to liquid ratio
across much of the region will likely be less than 10:1.

Strong winds, with gusts around 45 mph, primarily along the
coast, and primarily during the morning. This will could cause
power problems, especially if there is already a snow load on
trees and power lines. However, the strongest winds may occur
before the heaviest snow, although that is still somewhat
uncertain. I also don't think these strong winds will contribute
too much to blowing snow; as mentioned previously, this will be
a very heavy wet snow which should limit the blowing snow

Wednesday night... Snow could linger through the evening, but it
should be tapering off as the low moves further away and it
looks like we lose the ribbon of low to mid level frontogenesis
through this time.

Thursday and Friday... High builds in, leading to a return to
tranquil weather. The snow pack could limit day time heating, so
have gone with the lower side of guidance for highs each day.

Saturday... Models continue to depict a very fast moving clipper
system through this period. If there is enough moisture
advection, may see a brief window of opportunity for light snow,
but anything with this system should not amount to much.

Saturday night - Monday...

the mid-level large scale features include additional energy digging
into the western CONUS trough, which amplifies a downstream ridge
over the central conus, while high latitude blocking INVOF the davis
strait slowly breaks down. This all influences the placement and
amplitude of the trough across the northeast CONUS and southeast
canada, and the shortwave disturbances moving through this feature.

In particular, there is alot of uncertainty regrading the placement
and amplitude of the central CONUS ridge, with even an apparent
omega or rex block appearance, depending on the model solution. This
all leads to a considerable amount of spread in the deterministic and
ensemble solutions regarding low pressure tracking from the great
planes on Saturday, with the potential for redevelopment off the mid-
atlantic coast on Sunday and into Monday.

Some solutions favor a slower and more suppressed track, which would
have less of an impact on our region, while others suggest a track
across our region, which would obviously have a significant impact.

But there is just too much dispersion in the solutions at this point
to lock onto any one in particular. What we can say is that there is
the potential for another impactful storm system this weekend. Some
of these impacts could include wintry precipitation and coastal
flooding. Depending on the just how impactful the storm system
Tuesday into Wednesday of this week is (e.G., heavy wet snow impacts
to trees, powerlines, and the extent of power outages), it's
important to keep in mind that any potential storm this weekend
could inhibit those recovery efforts.

Looking ahead to Monday, the pattern is favoring a return to fair
weather with temperatures at or above average.

Aviation 07z Tuesday through Saturday
The following discussion is for kphl, kpne, kttn, kabe, krdg,
kilg, kmiv, kacy and surrounding areas.

Today...VFR ceilings northward, lowering to MVFR possibly ifr from
phl phl south and eastward later this morning and this afternoon. A
mix of snow, sleet and rain is expected at many of the terminals,
with this occurring later today at abe to ttn. The precipitation
type forecast is low confidence as is the timing. More rain should
occur at miv and acy. Northeast winds increasing to 12-16 knots and
gusts to 25-35 knots with the highest winds closer to the coast.

Tonight... Variable MVFR ifr conditions with times of snow, sleet,
rain and perhaps freezing rain, which should start to transition to
all snow from west to east toward daybreak Wednesday. Most of the
precipitation should trend lighter for awhile tonight, which is
anticipated to improve the visibility for a time. Northeast or north-
northeast winds 10-20 knots with gusts 25-35 knots with the highest
gusts closer to the coast.


Wednesday and Wednesday night... Ifr and lower conditions
especially during the day Wednesday in snow, which could be
heavy at times. We may see some gradual improvement Wednesday
night. Northeasterly wind becoming northwesterly Wednesday night
with gusts 20 to 30 kt possible. Wednesday morning, gusts up to
40 kt possible at kacy. Moderate confidence.

Thursday and Friday... MostlyVFR conditions expected.

Northwesterly winds up to 15 kt. High confidence.

Saturday... MostlyVFR conditions expected with light and
variable winds. Moderate confidence.

Gale and storm warnings in effect.

Conditions will rapidly deteriorate on the waters through tonight as
low pressure develops off the mid-atlantic coast. Winds will reach
gale force quickly from south to north today, then storm force
starting early this evening resulting in dangerous conditions. Seas
will build rapidly through tonight given a strengthening northeast
flow, reaching 10-17 feet through tonight (3-7 feet on delaware bay).


Wednesday... Intermittent storm force conditions most of the
atlantic coastal waters and lower de bay with a NE wind
Wednesday. Intermittent gale conditions on upper de bay.

Wednesday night... Northwest flow with winds and seas slowly
subsiding to gale and then possibly SCA by Thursday daybreak.

Thursday... SCA northwest flow.

Thursday night - Saturday... Sub-sca conditions expected.

Tides coastal flooding
The beginning of the upcoming coastal flooding event is now within
24 hours. As a result, we have transitioned from the watch to
warnings and advisories.

The coastal flood watch was upgraded to a coastal flood warning for
the new jersey counties of ocean, southeastern burlington, atlantic
and CAPE may, and for the delaware counties of sussex and kent. We
added cumberland county to the warning, as well. The coastal flood
warning is in effect from 8:00 pm this evening until 5:00 am
Thursday to cover all three high tide cycles of concern.

Based on the wind trajectory, the coastal flooding may not quite
reach moderate in monmouth county and middlesex county. Also, it may
be delayed a bit in those areas. We have placed those two counties
under a coastal flood advisory and it is in effect from 9:00 am
Wednesday until 5:00 am Thursday.

The surge is forecast to push up delaware bay and into the far lower
delaware river, impacting the high tides there on Wednesday and
Wednesday night. A coastal flood advisory has been issued for new
castle county and kent county. It is in effect from noon on
Wednesday until 5:00 am Thursday.

Another prolonged period of tidal flooding appears imminent along
the coasts of new jersey and delaware and along delaware bay. The
high tide cycles of concern are tonight's, and the ones on Wednesday
and Wednesday night. The astronomical tides with the daytime high
tide are about a half foot lower than those with the nighttime high

We continue to favor the more robust etss based on the model trends
over the past few days. The guidance has been moving toward
increasing impacts associated with the storm.

An onshore flow has already developed and it will strengthen today.

The surge is expected to build around 1.0 to 1.5 feet from long
beach island northward, and around 1.5 to 2.0 feet from the atlantic
city area southward for tonight's high tide. Minor flooding should
begin from long beach island southward at that time.

The surge for the Wednesday high tide is forecast to be in the 2.5
to 3.0 foot range. It is expected to produce moderate coastal
flooding along much of the new jersey coast, the delaware coast and
delaware bay. The exception should be the northern part of the new
jersey coast where widespread minor flooding is anticipated. Also,
minor flooding should reach the the far lower part of the delaware

The wind is forecast to transition from northeast to north on
Wednesday night. However, water is expected to remain trapped along
our coast and we are anticipating another round of surge levels in
the 2.5 to 3.0 foot range. The degree of flooding is expected to be
similar to that on Wednesday.

At this point, no tidal flooding is anticipated for the upper
eastern shore of chesapeake bay.

Daily record snowfall
site 3 20 3 21 3 22
---- ---- ---- ----
phl 9.6" (1958) 4.7" (1932) 3.0" (1914)
acy 5.0" (1914) 5.9" (1889) 2.4" (1964)
ilg 10.3" (1958) 5.4" (1964) 3.0" (1943)
abe 16.5" (1958) 4.3" (1964) 2.6" (1992)
snowfall as of (3 18 18)
site march '18 rank since 7 1 rank
---- --------- ---- --------- ----
phl 7.6" 26 22.2" 56
acy 3.5" 17 28.0" 13
ilg 6.1" 24 19.9" 48
abe 7.5" 26 32.8" 39
daily record rainfall
site 3 20 3 21 3 22
---- ---- ---- ----
phl 1.76" (1958) 2.24" (2000) 1.90" (1977)
acy 2.56" (1958) 1.98" (2000) 1.54" (1903)
ilg 1.99" (1913) 3.21" (2000) 2.22" (1977)
abe 2.12" (1958) 1.42" (1983) 2.49" (1977)
rdg 3.03" (1958) 1.57" (1890) 2.70" (2000)
ttn 1.74" (1958) 2.02" (1980) 2.25" (1977)
ged 2.12" (1975) 1.94" (2001) 1.20" (1964)
mpo 2.13" (1975) 1.28" (1950) 2.74" (1980)

Phi watches warnings advisories
Pa... Winter storm warning from 6 pm this evening to 2 am edt
Thursday for paz070-071-101>106.

Winter storm warning from 6 pm this evening to 8 pm edt
Wednesday for paz054-055-060>062.

Nj... Winter storm warning from 6 pm this evening to 2 am edt
Thursday for njz001-007>010-012>027.

Coastal flood warning from 8 pm this evening to 5 am edt
Thursday for njz020>027.

Wind advisory from 8 am this morning to 6 pm edt this evening
for njz023>025.

Coastal flood advisory from noon Wednesday to 5 am edt
Thursday for njz016.

Coastal flood advisory from 9 am Wednesday to 5 am edt
Thursday for njz012>014.

De... Winter storm warning from 6 pm this evening to 2 am edt
Thursday for dez001>004.

Coastal flood warning from 8 pm this evening to 5 am edt
Thursday for dez002>004.

Wind advisory from 8 am this morning to 6 pm edt this evening
for dez003-004.

Coastal flood advisory from noon Wednesday to 5 am edt
Thursday for dez001.

Md... Winter storm warning from 6 pm this evening to 2 am edt
Thursday for mdz008-012-015-019-020.

Marine... Storm warning from 6 pm this evening to 6 pm edt Wednesday for

Storm warning from midnight tonight to 7 pm edt Wednesday for

Gale warning from 11 am this morning to 6 pm edt Wednesday for

Synopsis... Johnson
near term... Gorse
short term... Gorse
long term... Franck johnson
aviation... Gorse franck johnson
marine... Gorse franck johnson
tides coastal flooding... Iovino
climate... Franck

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
TCBM2 - 8573364 - Tolchester Beach, MD 7 mi48 min ENE 5.1 G 8 37°F 44°F1012.1 hPa
FSNM2 20 mi48 min ENE 11 G 13 38°F 1011.3 hPa
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 20 mi48 min ENE 8.9 G 11 39°F 1011.9 hPa
BLTM2 - 8574680 - Baltimore, MD 22 mi48 min E 8 G 11 39°F 44°F1011.5 hPa
CPVM2 24 mi48 min 40°F 31°F
CHCM2 - 8573927 - Chesapeake City, MD 25 mi54 min NE 4.1 G 6 36°F 42°F1013 hPa
APAM2 - 8575512 - Annapolis, MD 27 mi48 min 40°F 1011.2 hPa
TPLM2 - Thomas Point, MD 31 mi66 min ENE 9.9 G 11 40°F 42°F
RDYD1 - 8551910 - Reedy Point, DE 36 mi48 min 36°F 42°F1012.5 hPa
DELD1 - 8551762 - Delaware City, DE 36 mi48 min ENE 7 G 8.9 36°F 39°F1012.9 hPa
DRSD1 - Delaware Reserve, DE 41 mi156 min E 4.1 39°F 1013 hPa32°F
BSLM2 - Chesapeake Bay, MD 46 mi156 min NE 2.9 40°F 1012 hPa33°F

Wind History for Tolchester Beach, MD
(wind in knots)    EDIT      (on/off)   Help
1 day
2 days

Airport Reports
    EDIT      (on/off)   Help   Click EDIT to display multiple airports
AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Phillips Army Air Field / Aberdeen, MD12 mi2.1 hrsNE 610.00 miFair37°F31°F80%1014.5 hPa
Baltimore / Martin, MD14 mi69 minNNE 410.00 miFair37°F32°F81%1013.2 hPa
Baltimore, Inner Harbor, MD23 mi72 minno data mi40°F30°F68%1012.4 hPa
Bay Bridge Field, MD24 mi71 minENE 710.00 miOvercast39°F30°F70%1012.2 hPa

Wind History from APG (wind in knots)
Last 24hrCalmCalmCalmCalmCalmCalmNE7NE7E8E6E7E9S6E5E9E7SE5E7E6E7E6E6NE6NE8
1 day ago----------------------NW12W4NW5SE7SE4SW3W3CalmCalmCalm--CalmCalm
2 days agoW4--W4W4CalmSW7W10W8W15

Tide / Current Tables for Worton Creek entrance, Maryland
   EDIT   RT Ports Option   Weekend mode (on/off)   (on/off)   Help   One Week of Data
Worton Creek entrance
Click for Map
Tue -- 04:34 AM EDT     0.04 feet Low Tide
Tue -- 07:08 AM EDT     Sunrise
Tue -- 09:08 AM EDT     Moonrise
Tue -- 10:36 AM EDT     1.63 feet High Tide
Tue -- 05:28 PM EDT     0.06 feet Low Tide
Tue -- 07:16 PM EDT     Sunset
Tue -- 10:41 PM EDT     Moonset
Tue -- 11:03 PM EDT     1.31 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

Tide / Current Tables for Baltimore Harbor Approach, Maryland Current
   EDIT      (on/off)   Help   One Week of Data
Baltimore Harbor Approach
Click for Map
Tue -- 01:52 AM EDT     -0.77 knots Max Ebb
Tue -- 04:49 AM EDT     0.00 knots Slack
Tue -- 07:08 AM EDT     Sunrise
Tue -- 08:10 AM EDT     0.96 knots Max Flood
Tue -- 09:09 AM EDT     Moonrise
Tue -- 11:28 AM EDT     -0.00 knots Slack
Tue -- 02:36 PM EDT     -0.86 knots Max Ebb
Tue -- 05:56 PM EDT     0.00 knots Slack
Tue -- 07:17 PM EDT     Sunset
Tue -- 08:39 PM EDT     0.61 knots Max Flood
Tue -- 10:42 PM EDT     Moonset
Tue -- 11:26 PM EDT     -0.00 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

Weather Map and Satellite Images
       (on/off)   HelpWeather Map
GOES 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.
target = "new">Link to Loop

Other links: Northern Pacific     Contential US     Full GOES-East
Wind Forecast for Philadelphia/Mount Holly, PA (4,6,7,8)
      (on/off)   Help

Ground Weather Radar Station Dover AFB, DE
   (on/off)   Help
weather_mapweather_map weather_map

Ad by Google

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.