Casco Bay Marine Forecast
|This Afternoon...E Winds Around 5 Kt Late This Morning And Early Afternoon, Becoming Light And Variable. Seas 3 To 5 Ft. Areas Of Fog. Snow Early. Rain Late This Morning And Early Afternoon. A Chance Of Rain Or Snow Late. Vsby 1 To 3 Nm.
|Tonight...N Winds Around 5 Kt, Increasing To 10 To 15 Kt With Gusts Up To 20 Kt After Midnight. Seas 3 To 5 Ft. Areas Of Fog In The Evening With Vsby 1 To 3 Nm.
|Sat...Nw Winds 15 To 20 Kt With Gusts Up To 30 Kt. Seas 2 To 4 Ft.
|Sat Night...Nw Winds 10 To 15 Kt, Diminishing To 5 To 10 Kt After Midnight. Gusts Up To 25 Kt. Seas 2 To 4 Ft. Light Freezing Spray.
|Sun...W Winds 5 To 10 Kt, Becoming Sw 10 To 15 Kt With Gusts Up To 20 Kt In The Afternoon. Seas 2 To 4 Ft. Light Freezing Spray In The Morning.
|Sun Night...Sw Winds 15 To 20 Kt With Gusts Up To 30 Kt. Seas 2 To 4 Ft.
|Mon...W Winds 10 To 15 Kt With Gusts Up To 25 Kt. Seas 2 To 4 Ft.
|Mon Night...Nw Winds 5 To 10 Kt With Gusts Up To 20 Kt, Becoming Sw After Midnight. Seas 2 To 4 Ft.
|Tue...S Winds 5 To 10 Kt, Increasing To 10 To 15 Kt In The Afternoon. Seas 2 To 3 Ft.
|Tue Night...S Winds 10 To 15 Kt, Increasing To 15 To 20 Kt After Midnight. Seas 2 To 4 Ft. A Chance Of Rain After Midnight.
| Area Forecast Discussion
National Weather Service Gray ME
1047am EST Fri Feb 23 2024
A weak system with light precipitation in the form of inland snow and coastal/southern rain exits to the east by this evening, bringing an end to any sort of minor travel impacts resulting from it. The system is pushed along by a cold front, which will provide a cold and blustery day on Saturday. High pressure crosses on Sunday, providing lighter winds but more notably a warm return flow which will see temperatures soaring well above seasonal averages through much of next week.
Near Term - Until 8pm This Evening
1048 AM Latest update was to include fog in the forecast for the rest of today and this evening.
Prev Disc... Update... A mixture of rain and snow continues across portions of the forecast area. Have modified temperatures and dew points in the near term portion of the forecast. Rain will continue over far southern areas of New Hampshire and along and near the coastline with temperatures climbing into the upper 30s to lower 40s. Have tweaked high temperatures downwards by a couple degrees for this afternoon. Otherwise, latest high res guidance suggests snow will continue over central and northern areas before ending this afternoon.
Prev Disc... 625 AMLittle to update other than tweaking T/Td trends with latest observations and hires guidance. light snow or a rain/snow mix is bring observed over many terminals this morning. While local webcams show accumulations have been tough to stick, there may still be some slick spots around.
Previously...Temperature profiles in forecast soundings continue to support a switch away from any fzra/sleet to more rain/snow as time goes on this morning, and this is meshing well current observations, even though a couple instances of freezing rain or sleet can't be ruled out over the next couple hours.
As of 330 AM, temperatures are largely in the lower 30s across the region with some upper 20s mixed in across the north. We're also starting to see some some mid 30s start to creep in across southern NH with KMHT reporting a mix of rain and snow and KASH reporting just rain. Light southerly flow ahead of a frontal boundary that will cross later will continue to slowly bring these warmer readings northward through this morning and afternoon, resulting in a switch to mostly rain south of the mountains with a rain/snow mix prior to this occurring. However, I have extended the rain/snow mix a little longer before the switchover as I think we could still see snow mixing in with surface temps of 34-36F based on the forecast soundings.
In areas where temps are near or just below freezing, there could be some localized slick roadways this morning, especially going farther north as the colder temps could allow more snow to accumulate with ptype also remaining snow longer.
Hi-res guidance is continues to trend quicker with this precip exiting the region, generally from late morning to early afternoon across NH and then through the afternoon across western Maine. Snowfall accums range from a light coating inland up to an inch or so toward the foothills and mountains, possible a couple inches in the higher peaks. Once this precipitation winds down, guidance is in pretty good agreement with most of the region in the reaching the upper 30s to low 40s this afternoon, possibly mid 40s in portions of NH.
Short Term - 8pm This Evening Through 6pm Saturday
Mostly dry conditions are in store for tonight with a couple of exceptions. The first is a chance of upslope snow showers in the mountains, and the second will be along the coast where another wave of low pressure could bring a few rain or snow showers. Skies will remain mostly cloudy for much of the night until a secondary front brings a big push of cooler and drier air toward day break Saturday. As the second front pushes through northwest winds will pick up, gusting to around 30 mph at times, dropping wind chills into the single teens south of the mountains by daybreak and a few degrees below zero to the north.
Skies will trend toward mostly sunny Saturday as the dry air continues to spill into New England. Despite the sunshine it will feel quite chilly out through the day with the breezy northwest winds of 30 to 35 mph and strong cold advection. Temperatures will likely won't recover beyond the 20s south of the mountains and in the teens to the north. The winds will make it feel much colder with wind chills in the single digits to the teens south of the mountains and a few degrees either side of zero across norther areas.
Long Term - Saturday Night Through Friday
Anomalous warmth is the big story heading into next week as an upper level ridge and its associated airmass builds from the southern Plains northeastward along the Eastern Seaboard... all the way up into Maritime Canada by around mid-week. Although 500 mb heigheights show anomalies of +1-2 sigma developing, anomalous but not extremely so, 850 mb temperatures are forecast to run 10-15 C above average which will bring a very unseasonably warm and humid airmass.
Starting off Saturday night...surface high pressure anchored over Appalachia noses into New England, allowing gusty winds from the daytime to diminish. The cool, dry airmass in place, coupled with the high moving in, should produce a decent radiational cooling night with single-digit-either-side-of-zero readings where we're able to efficiently decouple, teens elsewhere. By Sunday we'll be on the return flow side of the departing ridge axis, bringing a light southerly or southwesterly flow and the start of the warming trend. Highs will be seasonable or a touch warm, in the 20s north to around 40 in the lower Merrimack Valley under mostly sunny skies. High clouds associated with the next system increase late.
Sunday night into Monday... low pressure well north over Hudson Bay will push an attendant cold front east through the lower Great Lakes and into Maritime Canada. Although the parent circulation will be well displaced from New England... an upper level trough axis and associated vorticity maximum should still support light snow and rain shower activity with the crossing front, although low level moisture depth will likely limit coverage especially outside of the mountains. Warm southwest flow ahead of the front will have temperatures warming into the 30s across the north... 40s to near 50 south of the mountains.
Overall the passing wave won't make much of a dent in the overall warming trend with heigheights quickly rebounding in its wake. By Tuesday morning, the surface high pressure axis will have slipped offshore with an onshore flow regime setting up. The increase in humidity and cloud cover somewhat stunts surface warming relative to the quickly warming middle and upper levels, although highs are still forecast to be well above average... into the 40s and perhaps into the low-50s if low level clouds have less of an impact.
The remainder of the forecast has pretty widely varying outcomes depending on the progressiveness of the next system... but the theme is that we'll have more widespread rain through the region during the middle of the week along with warm and humid conditions. Record high temperatures may be too high to reasonably attain given clouds and humidity, however record warm overnight low temperatures may be in reach.
SCA (Small Craft Advisory) conditions persist across the outer waters as seas remain 5-7 ft. Wind gusts will approach 25 kt at times through this afternoon as southerly flow increases a head of a frontal boundary and weak low pressure. Behind the front, winds become westerly this evening and more northerly tonight while experiencing a brief lull before north to northwest winds ramp up Saturday morning morning and afternoon with gusts to around 30 kt. These winds and cooler air moving in will lead the the possibility of freezing spray Saturday afternoon.
SW winds increase over the waters Sunday night into Monday with 25-30 kt gusts coinciding with 4-6 ft seas likely. Winds turn NW and diminish below 20 kts behind a passing front Monday night. The next system crosses the waters around Wednesday or Thu with potential for gale force winds out of the SW.
NOAA Gray/Portland ME Office - Watches - Warnings - Advisories
Small Craft Advisory until 7pm EST Saturday for ANZ150-152- 154. Small Craft Advisory from 5am to 7pm EST Saturday for ANZ151- 153.