Monday, January21, 2019 L-36.com


Marine Weather and Tides
Siasconset, MA

Version 3.4
What's New / NOTES
10/6/2018 Colors of tide XTide graphs changed to emphasize that they were upgraded. See next note. Comments welcome.
10/4/2018 I have fixed XTide and updated the harmonic files. There were some name changes so you might have to click EDIT to find the new station name.

Sunrise 7:04AMSunset 4:48PM Monday January 21, 2019 8:50 AM EST (13:50 UTC) Moonrise 6:32PMMoonset 8:15AM Illumination 100% Phase: Full Moon; Moon at 15 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
ANZ005 610 Am Est Mon Jan 21 2019
Synopsis for eastport me to stonington me out 25 nm.. Low pres will move ne and away through the maritimes today and tonight. High pres will build in from the W on Tue and slide S of the waters Tue night.


7 Day Forecast for Marine Location Near Siasconset, MA
   Hourly   EDIT   Help
location: 38.84, -69.85     debug


Area Discussion for - Boston, MA
      (on/off)   Help   NOTE: mouseover dotted underlined text for definition
Fxus61 kbox 211241
afdbox
area forecast discussion
national weather service boston norton ma
741 am est Mon jan 21 2019

Synopsis
Arctic air pours into our region today behind the departing storm,
bringing dangerously cold wind chills. Moderating temperatures
Tuesday into Wednesday, then another storm brings a soaking rain
late Wednesday through Thursday night. Return of cold and mainly dry
conditions Friday into this weekend.

Near term until 6 pm this evening
No major changes this morning. Brought the forecast back in line
with observed trends.

Previous discussion...

a much drier morning on tap than 24 hours ago. The low center
is exiting off the coast of maine this morning while the 500 mb
center lags behind over northern new york. Skies have cleared
out for much of southern new england overnight as drier air
wraps around the low. That won't last long, though, as much of
the region will see a good deal of cloud cover on Monday. The
500 mb low will bring a deep mid level cold pool and a good
plume of low and mid level moisture with it from canada. Clouds
fill in through the morning and expand from the coast where
ocean effect clouds are already evident on IR satellite.

Dangerous icy conditions remain a risk for the morning commute
where rain from yesterday's storm remains frozen. Untreated
roads especially will be very slick and there is no thaw
forecast for the next 48 hours. Take it slow.

With a truly arctic airmass in place (h85 temps down to -25 c)
ssts in the low 40s, and NW winds, the atmosphere is ripe for
ocean effect snow showers as well. Delta t between the sea
surface and the top of the mixed layer still look to be around
25-30c producing >800 j kg of cape. Given the wind trajectory
snow showers should remain over the outer cape. Before its all
said an done Monday night we're looking at a possible 1-2" of
snow.

The biggest story of the day for most will be the absolutely
frigid temperatures and wind chills. Arctic air spilling south
will only allow temperatures to climb into the single digits,
below zero for the highest elevations. If the cold wasn't harsh
enough, the pressure gradient between the low exiting to our
northeast and the high building in from the west will mean very
gusty north winds and CAA efficiently mixing down gusts 35-40
mph. Together they'll make it feel more like -10 to -25 f. A
wind chill advisory is in effect for most of southern new
england (besides the CAPE and islands) while a wind chill
warning covers western and north central ma including the
berkshires and worcester hills. Today will not be the nicest day
to spend outdoors.

Short term 6 pm this evening through 6 pm Tuesday
Overnight and Tuesday mid level heights are on the rise as a
high pressure ridge builds into the northeast. This will relax
our pressure gradient and bring down the winds by Tuesday as the
surface low moves over head. Overnight, skies clear rapidly
from the west as dry air moves in and plenty of Sun is in store
for Tuesday. Don't let the sunshine fool you, though, since
we'll remain locked in a very cold pattern until Wednesday. Lows
Tuesday morning in the single digits to below zero will rebound
to the mid 20s by Tuesday. It's not warm but compared to the
single digit highs of Monday, plus the lack of wind, Tuesday
will feel practically balmy.

Long term Tuesday night through Sunday
* highlights...

- soaking rains late Wednesday through Thursday night
- return cold air Friday into the weekend
- watching a following early week storm system
* discussion...

21 00z guidance remains in rather good overall agreement through
Wednesday, then differences start to amplify through early next
week. Will prefer a consensus approach to this forecast to smooth
over the less predictable details through Wednesday, and to minimize
the timing and amplitude differences for the second half of this
forecast period.

In general, broad mid level ridge over the eastern usa shifts over
the north atlantic Wednesday, while a trough dominates much of the
central usa. This configuration should result in a potent SW flow.

This will not only track a low pressure our way toward mid week, but
also raise temperatures where mainly rainfall is expected. Decent
signal for low level temperatures to be about 1 standard deviation
above normal. Also looking like another moisture-rich system, with
precipitable water values about 3 standard deviations above normal.

Have high confidence in a period of wet weather sometime Wednesday
into Thursday. Depending upon timing, looking like snow to start
with a transition to all rain by late Wednesday afternoon. Small
risk for precipitation to end as snow towards NW ma Thursday
afternoon.

Once this low pressure departs our region, we should have another
period of very cold weather heading into this weekend. This could
set the stage for another winter storm early next week. Still lots
of moving parts with that storm, so not much confidence in the
details at this time.

Aviation 13z Monday through Friday
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Tuesday ... High confidence
today...

mainlyVFR cigs, but areas of MVFR across eastern ma
and CAPE islands. Sct flurries or snow showers possible. Nw
gusts to 30 to 35 kt with isolated 40 kts across SE coastal
terminals.

Tonight and Tuesday...VFR.

Kbos terminal... High confidence in taf.

Kbdl terminal... High confidence in taf
outlook Tuesday night through Friday ...

Tuesday night:VFR. Breezy.

Wednesday: mainlyVFR, with local ifr possible. Windy with local
gusts to 30 kt. Ra or fzra, with a chance of sn or pl.

Wednesday night: mainlyVFR, with areas ifr possible. Windy
with gusts to 30 kt. Ra or fzra.

Thursday: mainlyVFR, with local ifr possible. Strong winds
with areas gusts to 40 kt. Chance ra.

Thursday night:VFR. Windy with gusts to 35 kt. Slight chance
ra.

Friday:VFR. Breezy.

Marine
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Tuesday ...

nw gales persist through today in the strong cold advection.

With the arctic air pouring into the region and rough seas,
widespread moderate freezing spray will develop on all open
waters, with pockets heavy freezing spray.

Tuesday NW winds come down through the day, gusting 20-25 kts by
early afternoon. Seas start 5-7 ft with 9-11 ft on the outer
waters. By evening 2-4 ft for coastal waters and 5-8 ft outer.

Outlook Tuesday night through Friday ...

Tuesday night: winds less than 25 kt. Seas locally approaching
5 ft.

Wednesday: moderate risk for small craft advisory winds with
areas of gusts up to 30 kt. Areas of rough seas. Chance of
rain.

Wednesday night: low risk for gale force winds with gusts up to
30 kt. Areas of rough seas. Rain.

Thursday: moderate risk for gale force winds with gusts up to
40 kt. Rough seas up to 14 ft. Rain.

Thursday night: low risk for gale force winds with gusts up to
40 kt. Rough seas up to 13 ft. Chance of rain.

Friday: moderate risk for small craft advisory winds with gusts
up to 25 kt. Rough seas up to 11 ft.

Tides coastal flooding
Monday morning astronomical high tides are a few tenths higher along
the east coast. While both seas and surge will have subsided, there
is a lingering easterly swell and wave action offshore to lead to an
additional 0.1-0.3 foot surge.

With an astronomical tide around 11.9 at boston at 11am, there is
the risk for some spotty minor coastal flooding. Overall, the
flooding risk is lower, and will likely be limited to the typically
prone locations.

A coastal flood statement has been issued.

Box watches warnings advisories
Ct... Wind chill advisory until 8 am est Tuesday for ctz002>004.

Ma... Wind chill advisory until 8 am est Tuesday for maz005>007-
010>021.

Wind chill warning until 5 am est Tuesday for maz002-008-009.

Wind chill warning until 8 am est Tuesday for maz003-004-026.

Ri... Wind chill advisory until 8 am est Tuesday for riz001>007.

Marine... Heavy freezing spray warning until 6 am est Tuesday for anz232.

Gale warning until 7 am est Tuesday for anz232>234.

Freezing spray advisory until 11 am est Tuesday for anz231-
233>235-237-250-251-254>256.

Gale warning until 9 pm est this evening for anz230.

Gale warning until 6 am est Tuesday for anz231-251.

Gale warning until 10 pm est this evening for anz236.

Gale warning until 5 am est Tuesday for anz235-237.

Gale warning until 10 am est Tuesday for anz250-254>256.

Synopsis... Belk sipprell bw
near term... Belk bw
short term... Bw
long term... Belk
aviation... Belk bw
marine... Belk bw
tides coastal flooding...



Weather Reporting Stations
   EDIT       (on/off)   Help   NOTE: Click on distance to see the station location on a map

Airport Reports
    EDIT      (on/off)   Help   Click EDIT to display multiple airports
AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Nantucket, Nantucket Memorial Airport, MA168 mi58 minW 145.00 miLight Snow8°F1°F73%1006.5 hPa

Wind History from ACK (wind in knots)
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
12
AM
1
AM
2
AM
3
AM
4
AM
5
AM
6
AM
7
AM
8
AM
Last 24hrS20
G27
S22
G30
S27
G37
S20
G27
SW16
G27
S17S13S16SW16
G22
N24
G27
NW19
G30
NW19
G24
NW17
G22
NW16
G24
NW17
G24
NW16
G26
NW17
G25
NW19
G29
W18
G28
NW18
G26
W16
G24
W16
G24
W14W14
1 day agoN8NE8E9NE5NE9E8E10E12E11
G17
E13E12
G21
E11E12E11
G21
E16E17
G25
E16
G26
E19
G25
E16
G25
E20
G28
SE19
G30
SE21
G28
S18S14
2 days agoE7E7E9NE10E9NE9NE6NE4N3NW4NW6NW4W3NW4NW4W4W5NW6NW6NW7NW10N7N7N6

Tide / Current Tables for
   EDIT   RT Ports Option   Weekend mode (on/off)   (on/off)   Help
Tide / Current Tables for
   EDIT      (on/off)   Help
Weather Map and Satellite Images
       (on/off)   HelpWeather Map
wmap_A
GOES Local Image of Northeast    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
Wind Forecast for Boston, MA (8,2,3,4)
      (on/off)   Help

Ground Weather Radar Station Upton, NY
   (on/off)   Help
weather_mapweather_map weather_map

Ad by Google

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 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.