Cape Cod Bay Marine Forecast
| Tonight...Sw Winds 5 To 10 Kt, Becoming N 10 To 15 Kt After Midnight. Gusts Up To 20 Kt. Seas Around 2 Ft. A Chance Of Showers And Tstms. |
| Wed...N Winds 10 To 15 Kt. Seas 2 To 3 Ft. A Chance Of Showers. |
| Wed Night...E Winds Around 5 Kt, Becoming Sw After Midnight. Seas Around 2 Ft. |
| Thu...S Winds Around 5 Kt, Increasing To Around 10 Kt In The Afternoon. Seas 1 Foot Or Less. A Chance Of Showers. |
| Thu Night...S Winds 10 To 15 Kt. Seas Around 2 Ft. A Chance Of Showers. |
| Fri...W Winds Around 10 Kt. Seas Around 2 Ft. A Chance Of Showers. |
| Fri Night...Nw Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas 2 To 3 Ft. |
| Sat Through Sun...Sw Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas 2 To 3 Ft. |
| Sun Night...Sw Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas Around 2 Ft. A Chance Of Showers. Winds And Seas Higher In And Near Tstms. Seas Are Reported As Significant Wave Height, Which Is The Average Of The Highest Third Of The Waves. Individual Wave Heights May Be More Than Twice The Significant Wave Height. |
| Area Forecast Discussion National Weather Service Boston/Norton MA 320pm EDT Tuesday July 27 2021 Synopsis A cold front passed through southern New England Tuesday evening. Some showers may linger Wednesday morning and it will be quite a bit cooler than today. Cool and unsettled weather is expected sometime Thursday into early Friday. Dry and pleasant weather is expected to start this weekend. Near Term - Through Tonight A cold front associated with a low pressure system well to our north passes through our area this evening. Thunderstorms, some of which may be severe, will begin to develop across our area after 5 pm. Instability is increasing across the area, with the MUCAPE approaching 1500 J/kg. Dynamics are also rather impressive this afternoon and evening, with 0-6 km shear approaching 50 kt along the MA/NH border. For a short period of time closer to sunset, CAPE values may surge towards 2000J/kg. K index values also increase into the mid and upper 30s ahead of the cold front. While storms may begin to develop around 5pm, the best shot for the strongest storms will be between 6-10 pm this evening, primarily north and west of Worcester. Because the cold front progresses through our area so late this evening, it will be a battle between instability and dynamics to determine how far south and east the severe potential extends. CAPE/Instability diminishes rapidly after sunset, dropping to a few hundred joules. However, shear values increase across southern MA, RI and CT which may carry storms south and east. Dewpoints will also remain relatively high, in the low to mid 60s, which may fuel thunderstorms. Because thunderstorms will develop prior to sunset, post sunset development may not be necessary for strong storms to progress eastward, it is just a matter of if the dynamics remain robust enough to maintain storm strength. The primary threat associated with these storms will be gusty winds and embedded downpours. Behind the front, much cooler air rushes in and winds shift from westerly to northerly. A few lingering showers and a rumble of thunder may develop behind the cold front as a developing shortwave approaches. .SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... Highlights... *Lingering showers into Wednesday morning, MUCH cooler behind the cold front. Wednesday... Showers diminish through the day on Wednesday. Residual clouds will thin out with breaks of sun developing during the afternoon, especially across eastern areas. 850mb temps drop dramatically from their Tuesday peaks, into the low teens and upper single digits, suggesting that temperatures may struggle to climb into the low 70s in eastern MA. Temperatures will be slightly higher across the Connecticut River Valley as NE winds develop, primarily cooling eastern zones. Wednesday Night... Low temperatures on Wednesday night will likely be limited by dewpoints, which linger in the upper 50s and low 60s. Thicker clouds will overspread from west to east, with more sun than clouds across eastern MA and RI by sunrise on Thursday. Winds shift from the northeast to south/southeast. Patchy fog is possible across the interior. Long Term - Thursday Through Tuesday * Below normal temperatures through early next week * Multiple frontal passages provide chances for showers and thunderstorms with periods of dry weather in between. Southern New England is expected to remain on the periphery of a mid level low over Labrador and the Maritimes through late this week. As this low rotates north, another mid level low should take its place over Quebec before moving over the Maritimes this weekend. This colder air will lead to below normal temperatures through early next week. The other factor to support precipitation will be a series of fronts. A warm front will try to move north across our region Thursday, followed by a cold front sometime Thursday night into Friday. At this time, kept a mention of showers Friday morning, but there is a possibility this front moves faster, leading to a drier day. Expecting dry and cool conditions Saturday. Sunday should be mainly dry to start, with yet another chance for showers as a cold front arrives later in the day. Have little confidence in the timing of another front and possible coastal low south of New England early next week. Maintained a chance for showers for now. However, thinking this is likely to change over the coming week. Marine Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Tonight through Wednesday Night...High Confidence. Winds and seas will remain below small craft advisory criteria through Wednesday night. A brief surge in higher winds between 20-30 kt is expected along a passing cold front Wednesday evening. /Outlook /Thursday through Sunday/... Thursday: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain showers. Thursday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers, patchy fog. Friday: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers. Friday Night through Saturday: Winds less than 25 kt. Areas of seas approaching 5 ft. Saturday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Sunday: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain showers. Hydrology No active river flood warnings are in effect for rivers and waterways across southern New England. However, after having a tremendous amount of rainfall from early to mid July, many rivers and streams continue to run above to much above normal across most of MA, northern CT, and far northern RI. This is resulting in swift currents that would not typically be seen in the summer. These swift currents can catch those swimming or tubing/kayaking on area waterways off guard. There have been 3 total reports of drownings in the last week on the Farmington River in CT and Squannacook River in MA given the higher than usual flows and swift currents. Those with interests swimming, tubing or kayaking on area rivers and waterways should be aware that swift currents due to high flows are occurring. This can result in dangerous conditions, and it is generally discouraged to swim, inner-tube, or kayak until flows decrease. NOAA Boston MA Office: Watches - Warnings - Advisories CT...Air Quality Alert until 11pm EDT this evening for CTZ002>004. MA...Air Quality Alert until midnight EDT tonight for MAZ004>007- 026. RI...None. MARINE...None. |
Boston MA Radar