Casco Bay Marine Forecast
| This Afternoon...Sw Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas 2 To 4 Ft. |
| Tonight...Sw Winds 10 To 15 Kt, Becoming W 15 To 20 Kt After Midnight. Seas 2 To 4 Ft. |
| Sun...Nw Winds 15 To 20 Kt With Gusts Up To 30 Kt. Seas 2 To 4 Ft. |
| Sun Night...Nw Winds 15 To 20 Kt With Gusts Up To 25 Kt, Diminishing To 5 To 10 Kt After Midnight. Seas 2 To 3 Ft. |
| Mon...Nw Winds Around 5 Kt, Becoming S In The Afternoon. Seas Around 2 Ft In The Morning, Then 1 Foot Or Less. |
| Mon Night...S Winds 5 To 10 Kt. Seas Around 2 Ft. A Chance Of Showers In The Evening, Then Showers Likely After Midnight. |
| Tue...S Winds 10 To 15 Kt. Seas 2 To 3 Ft. Showers Likely, Mainly In The Morning. |
| Tue Night...W Winds 5 To 10 Kt. Seas 2 To 3 Ft. |
| Wed...W Winds Around 5 Kt, Becoming S In The Afternoon. Seas 2 To 3 Ft. |
| Wed Night...Sw Winds 5 To 10 Kt, Becoming N After Midnight. Seas Around 2 Ft. |
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Area Forecast Discussion National Weather Service Gray ME 1108am EDT Sat April 19 2025 Synopsis Warmer air moves into the area today as an area of low pressure tracks across Quebec with the attendant cold front crossing tonight. Chances of showers increase this evening as the cold front approaches. Northwest winds will gust 35-40 mph on Sunday in the wake of the cold front. High pressure builds in Sunday night into Monday. The next chance of showers arrives Monday night into Tuesday as low pressure approaches New England. Near Term - Until 6pm This Evening 11:05am Trended temps down slightly into the early afternoon with more cloud cover, but the warmth is still pushing northward today. Also increased POPs into the mid afternoon across western areas as a batch of showers across update New York looks to be holding together pretty well as it moves eastward. Otherwise, the forecast remains on track at this point. 640 AM...Warm front is lifting through the area with the initial round of showers exiting the coast and eastern zones at this hour. Upstream there is some convection over northern NY and this convection still looks to track towards the mountains around mid morning while areas south of the mountains will remain mostly dry. Some 06Z CAM solutions showed more eastward extent of thunderstorms with the cold front later today so for this update have mainly refined Probability of Precipitation and expanded the slight chances for thunder into the coastal plain. Previously... Latest radar shows an area of showers moving west to east across northern New England in association with a warm front lifting through the area. Surface observations indicate that this precipitation is reaching the ground as the low levels have moistened. This first area of showers is forecast to push east of the area around sunrise. Upstream there is a cluster of convection over Ontario that is forecast to track near the Canadian border through mid morning that will keep chances for showers and possibly a rumble of thunder over the mountains and north. South of the mountains looks to remain mostly dry into the afternoon with thinning cloud cover. This will allow for temperatures to rise into the mid to upper 70s across much of NH and SW Maine. There will also be breezy SW winds with gusts 25-30 mph. Highs across the mountains and north may be restricted to the 60s due to more cloud cover along with an onshore wind component keeping the Mid Coast cooler. A cold front will approach from the NW this afternoon bringing renewed chances for showers and some thunderstorms in the mountains and across central and southern NH. CAMs suggest that filtered sunshine along with dewpoints rising into the mid 50s will allow for 500-1000 J/kg of ML CAPE to build ahead of the cold front. Dry air in the mid levels may limit convective coverage along the front, although there has been an upward trend in the chances for some thunderstorms mid to late afternoon. Inverted V soundings suggest any robust storms that do develop could produce gusty winds while confidence is not high enough to put enhanced wording in the forecast. The best chances for some gusty storms will be across central and southern NH into SW Maine. Short Term - 6pm This Evening Through 6pm Sunday The cold front will continue to cross the area this evening and tonight with convection waning around sunset. The front will push offshore with cooler and drier air arriving on increasing NW winds. Lows tonight will range from the low 30s north to mid 40s south. The PGF will tighten across the area Sunday between deepening low pressure over the Canadian Maritimes and high pressure over the Great Lakes. Winds at the top of the mixed layer will be around 40 kts and with favorable mixing, winds are forecast to gust 35 to 40 mph across the area with higher gusts across eastern zones and in the mountains. This mixing will also allow for dry air to mix to the surface with RH dropping to around 20 percent south of the mountains. The combination of these gusty winds and low RH will bring elevated fire weather conditions. Otherwise it will be mostly sunny with highs ranging from the low 40s north to mid 50s south. Long Term - Sunday Night Through Friday 04Z Long Term Little change in the latest NBM suite of guidance. After a dry day on Monday, rain chances will increase Monday night into Tuesday as a weak triple point approaches from the west. Mainly dry weather and near seasonable temperatures look to follow for the middle of next week. Previously... Key Message: The steady march of spring continues with temps alternating between cool and warm. Two solid signals for precip around Tuesday and again at the end of the week...although timing remains low confidence in the second system. Forecast Details: There is a solid signal for precipitation Tue. Like the Sat event...there is broad consensus across model suites for a similarly light event. Additionally the best chances for rain will across the northern areas where the fire threat is already lowest. So that will have to be monitored thru midweek. By late in the week a western CONUS trough combined with a flattish ridge over eastern CONUS will result in a fast flowing pattern locally. The timing differences between waves have PoP generally spread out over several periods...but chance wording sounds appropriate given that uncertainty. Marine Short Term SCA (Small Craft Advisory) continues through today as a warm front lifts over the waters. Expect building waves until a cold front crosses Saturday night with winds shifting offshore. Offshore winds will gust to around 30 kts Sunday and a few gusts to 35 kts will be possible along the outer waters. Long Term Winds and seas will diminish Sunday night thru Monday morning as high pressure builds over the region. Warm front will lift into the Gulf of ME Tue...and bring the potential for some marine fog. Fire Weather Despite cool temps Sun...RH values will be very dry and winds will be gusty. Dewpoints may fall into the single digits and result in min RH around 20 percent south of the mountains. Northwest winds may be sustained in excess of 20 mph and gusting over 35 mph at times during the day. If showers don't produce much wetting rain Sat...that could leave fuels dry for Sun. NOAA Gray/Portland ME Office - Watches - Warnings - Advisories ME...None. NH...None. Marine Small Craft Advisory until 8pm EDT Sunday for ANZ150>154. |
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