Marine Weather Net

Casco Bay Marine Forecast


THIS AFTERNOON

NE
WINDS
5 - 10
KNOTS

TONIGHT

NE
WINDS
10 - 15
KNOTS

TUE

N
WINDS
5 - 10
KNOTS

TUE NIGHT

NW
WINDS
15 - 20
KNOTS

The Marine Weather Forecast In Detail:
ANZ153 Forecast Issued: 1155 AM EST Mon Nov 11 2019

GALE WATCH IN EFFECT FROM TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING
This Afternoon...Ne Winds 5 To 10 Kt, Increasing To 10 To 15 Kt With Gusts Up To 20 Kt. Seas 1 Foot Or Less, Then 1 To 2 Ft. Showers Likely Early, Then A Chance Of Sprinkles.
Tonight...Ne Winds 10 To 15 Kt, Becoming Se 5 To 15 Kt After Midnight. Gusts Up To 25 Kt. Seas 2 To 3 Ft. A Chance Of Rain. Vsby 1 To 3 Nm In The Evening.
Tue...N Winds 5 To 10 Kt, Becoming Nw 10 To 15 Kt With Gusts Up To 25 Kt In The Afternoon. Seas 2 To 4 Ft. Rain Likely In The Morning, Then Rain And Snow Likely In The Afternoon With Vsby 1 To 3 Nm.
Tue Night...Nw Winds 15 To 20 Kt With Gusts Up To 30 Kt. Seas 2 To 4 Ft. A Chance Of Snow Showers. Light Freezing Spray After Midnight. Vsby 1 To 3 Nm.
Wed...Nw Winds 15 To 20 Kt, Becoming 10 To 20 Kt In The Afternoon. Gusts Up To 30 Kt. Seas 2 To 3 Ft, Subsiding To 1 To 2 Ft In The Afternoon. Light Freezing Spray In The Morning.
Wed Night...Nw Winds 5 To 15 Kt With Gusts Up To 20 Kt, Becoming 5 To 10 Kt After Midnight. Seas 1 Foot Or Less.
Thu...W Winds Around 5 Kt. Seas 1 To 2 Ft.
Thu Night...Sw Winds 5 To 10 Kt With Gusts Up To 20 Kt. Seas Around 2 Ft. A Chance Of Rain And Snow Showers. Vsby 1 To 3 Nm.
Fri...Sw Winds 5 To 15 Kt With Gusts Up To 25 Kt. Seas Around 2 Ft.
Fri Night...Nw Winds 10 To 20 Kt With Gusts Up To 25 Kt. Seas 2 To 3 Ft.
SHARE THIS PAGE:           
Area Forecast Discussion
National Weather Service Gray ME
1156am EST Monday Nov 11 2019

Synopsis
Cold air will slowly move southward through our forecast area today and tonight while low pressure develops to our southwest. This will set the stage for a wintry mix for most of the forecast area through Tuesday. In the wake of the low, a very cold and windy day is in store for Wednesday. Colder than normal weather will continue thereafter, with mainly dry conditions expected into the weekend.

Near Term - Until 6pm This Evening
1155 AM...CLuster of showers/spkls along the ME coast popped up and is dying off attm. I have covered a lot of the area outside the mtns and the CT vly with the spkls/flurries tag thru most of the day, as I can see a few more popping up thru the day, but generally very low impact stuff. Also adjusted POPs a bit for the precipitation coming in from the best, and slowing its arrival time by an hour so, based on current radar, but thinking we see some showers popping up ahead of the main precipitation shield as well. Outside of southern NH, I think temps have reached their maxes for the day, and will slowly fall off thru the afternoon.

940 AM...Forecast updated a bit, mainly to cover the more spotty/showery nature of the precipitation thru the morning into the afternoon, especially in the south. This, thanks to drier air at the lower levels. and lack of a good forcing mechanism until this afternoon. Any changes to p-type were minor, and mainly based on small scale timing thru the afternoon. Highs were bumped in many spots, because they have climbed above the forecast already, but highs are likely to be realized this morning as temps fall slowly during the afternoon.

Update... Have updated the forecast based on current observational trends and mesoscale models. 12Z sounding at GYX now showing moisture just beginning to saturate mid levels of the atmosphere, while a dry layer remains near the surface. Radar showing some light echoes associated with this mid level moisture, however surface observations indicate there is little in the way of precipitation making it to the ground.

Made minor adjustments for temperatures, dew points and winds this morning. Otherwise, advisories and warnings remain in place for upcoming system.

Prev Disc... Cold air will gradually ooze southward across the forecast area today in the wake of a cold front. This SFC front will become stationary just to the south of our forecast area, with reinforcing cold air advecting in on northerly winds. At the same time, robust warm air advection will occur above the boundary layer which will result in a mixed precipitation event for many zones, with all snow restricted to close to the Canadian border.

The warm air advection aloft will allow light precipitation to break out this morning across mainly central NH and adjacent western ME. Mainly light snow is expected with this into the afternoon hours, especially at higher elevations where boundary layer heating will be less. At lower elevations across the coastal plain of ME and southern NH, rain or a rain/snow mix seems more likely into this afternoon. An ensemble approach was employed to derive snowfall amounts prior to 00z this evening, with 1 to 2 inches forecast for mainly the While Mountains eastward into the western ME mountains. However, up to an inch will be possible at lower elevations in Maine (away from the immediate coast) where the cold air draw from the north will be stronger earlier on without the risk of being affected by the warming temperatures aloft just to the south.

As far as headlines go, went with a winter storm warning for our zones adjacent to the Canadian border where sub-freezing air will hang on longest throughout the column allowing for 6+ inches of snow. Farther south, advisories have been issued where any light snow accums will change to freezing rain (and freezing drizzle) and sleet. There remains some uncertainty with boundary layer temperatures across southernmost zones in NH and coastal southern ME. There's a good chance that those zones will stay just above freezing during the event, so will hold off there. In addition, precipitation amounts near the Mass border will be very light as the vast majority of the forcing for ascent will be farther north.

Short Term - 6pm This Evening Through 6pm Tuesday
Warm air aloft will continue to flood northward this evening while the boundary layer remains cold. This will mean any light snow will turn to freezing rain, rain, and sleet across much of the forecast area south of the Canadian border zones. In addition, dry air aloft will move in to most zones, especially the coastal plain, likely allowing the dominant precipitation type to be drizzle or freezing drizzle tonight. While ice accretion is expected to remain light, it could very well make for slick travel. Therefore, winter weather advisories have been issued where the best chance of freezing rain or freezing drizzle is expected to take place.

On Tuesday, boundary layer temperatures may briefly warm above freezing mitigating the chances for icing on roads across southern zones and on the coastal plain. However, will keep advisories going all day as we expect the low level cold air to rush back in from the west before the entire column cools to below freezing. Therefore, there may be a break in the light freezing rain/drizzle, but it should redevelop as the low level cold air sloshes back in. The entire column will eventually cool to allow for a period of light snow all zones by later Tuesday afternoon and this may make for a slippery Tuesday afternoon and evening commute with some light accumulating snow on top of water/ice as temperatures plummet.

Long Term - Tuesday Night Through Sunday
Gusty northwesterly winds will occur behind the departing area of low pressure. Mountain snow showers will be possible Tuesday night into Wednesday morning in the mountains with downslope conditions elsewhere.

Temperatures will be well below normal for this time of the year with readings falling into the single numbers in the north to the teens in the south. Gusty winds will make for wind chill values below zero in the north and single numbers right at the coast.

Temperatures may drop another few degrees colder Wednesday night as high pressure crests over the region. Light winds may allow for radiational cooling with most areas dropping to zero to 10 degrees above. Overnight lows will be very dependent on whether an mid and high level cloudiness moves into the region as a long wave trough begins to approach from the west.

Another large trough will remain to our west Thursday into Friday. Temperatures will moderate to near normal levels on Friday ahead of an approaching arctic front.

Scattered snow showers and possibly a few snow squalls may cross the region late in the day Friday into Friday evening. Strong winds behind the front will allow for low wind chill values once again.

Marine
Short Term /Through Tuesday/...Winds and seas are generally expected to remain below SCA (Small Craft Advisory) thresholds through much of Tuesday. However, strong west winds are expected starting Tuesday evening with gales possible.

Long term...Gale force wind gusts may occur for the remainder of Tuesday night into Wednesday morning as the upper level low shifts to the east and winds align through a deep layer. Cold air advection over the relatively warm ocean waters to allow for the potential for gusts over 35 kts.

NOAA Gray/Portland ME Office - Watches - Warnings - Advisories
ME...Winter Weather Advisory until 7pm EST Tuesday for MEZ012>014- 020>022. Winter Weather Advisory from 5pm this afternoon to 7pm EST Tuesday for MEZ018-019-024>028. Winter Storm Warning until 7pm EST Tuesday for MEZ007>009. NH...Winter Weather Advisory until 7pm EST Tuesday for NHZ002>006. Winter Weather Advisory from 5pm this afternoon to 7pm EST Tuesday for NHZ007>010. Winter Storm Warning until 7pm EST Tuesday for NHZ001. MARINE...Gale Watch from Tuesday afternoon through Wednesday morning for ANZ150>154.