Montauk NY to Marthas Vineyard out 20 NM South of Block Island Marine Forecast
| Today...Sw Winds 5 To 10 Kt, Becoming W This Afternoon. Seas 3 To 4 Ft. Wave Detail: Se 3 Ft At 7 Seconds And W 2 Ft At 4 Seconds. Patchy Fog. Showers Likely. Vsby 1 Nm Or Less. |
| Tonight...W Winds Around 10 Kt, Becoming Nw After Midnight. Gusts Up To 25 Kt. Seas Around 3 Ft. Wave Detail: W 3 Ft At 4 Seconds And Se 3 Ft At 7 Seconds. Patchy Fog In The Evening With Vsby 1 Nm Or Less. |
| Sun...Nw Winds Around 10 Kt, Becoming W With Gusts Up To 20 Kt In The Afternoon. Seas 2 To 3 Ft. Wave Detail: Nw 3 Ft At 4 Seconds And Se 2 Ft At 7 Seconds. |
| Sun Night...W Winds 10 To 15 Kt With Gusts Up To 25 Kt. Seas 2 To 4 Ft. Wave Detail: W 3 Ft At 4 Seconds And Se 2 Ft At 7 Seconds. |
| Mon...W Winds 10 To 15 Kt. Gusts Up To 20 Kt In The Morning. Seas 2 To 3 Ft. Wave Detail: Nw 2 Ft At 4 Seconds And Se 1 Ft At 7 Seconds. |
| Mon Night...W Winds 10 To 15 Kt, Becoming E After Midnight. Seas Around 2 Ft. |
| Tue And Tue Night...S Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas 2 To 3 Ft. |
| Wed...S Winds Around 15 Kt With Gusts Up To 25 Kt. Seas 3 To 4 Ft. A Chance Of Showers. |
| Wed Night...W Winds 15 To 20 Kt With Gusts Up To 25 Kt. Seas 3 To 5 Ft. 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 349am EDT Sat April 20 2024 Synopsis A round of showers mainly this morning will persist into early afternoon across parts of Rhode Island and southeast Massachusetts...but partial sunshine should develop across the interior later today. A ridge of high pressure will result in dry weather Sunday through Tuesday with mild days and cool nights along with elevated fire weather potential. Unsettled, wet and cool on Wednesday. Turning drier late in the week. Near Term - Until 6pm This Evening 345 AM * Showers develop this morning with a few downpours too * Bulk of the showers come to an end late morning into mid afternoon * High temps this afternoon in the upper 50s to the middle 60s A shortwave and its associated cold front was approaching from the west this morning. In advance of this front...increasing low level moisture has allowed low clouds to overspread much of the region very early this morning. A few showers were starting to develop across western MA very early this morning. We expect the activity to increase in areal coverage & intensity as the front pushes east into an environment where PWATs (Precipitable Waters) will exceed 1 inch. So expect showers to blossom across the region through daybreak with a few brief downpours too. This front is progressive and we expect the showers to pretty much come to an end from northwest to southeast by mid afternoon in most locations and earlier across the interior. Partial sunshine will develop by mid to late afternoon northwest of I-95 and towards evening along the I-95 corridor. The partial sunshine coupled with the upper trough will result in enough diurnal instability to trigger a few additional showers later today...but the vast majority of this time will feature dry weather in a given locations. Given the cold temps aloft its not out of the question that a few of the late day showers contain some graupel. The relatively mild start coupled with some partial sunshine later today should allow areas northwest of I-95 to reach the lower to middle 60s. Southeast of I-95 where clouds/showers linger a bit longer...highs will be in the middle 50s to the lower 60s. The coolest of those readings will be across the Cape and Islands. Short Term - 6pm This Evening Through 6pm Sunday Key Points... * Clearing tonight with lows in the 30s to the lower 40s * Partly sunny a bit breezy Sunday with highs upper 50s/near 60 Details... Tonight... Lingering clouds across eastern New England should push east of the region this evening as drier air works in from the west. This should yield mostly clear skies and diminishing wind will allow for a good night of radiational cooling. Some locations will see low temps bottom out well down into the 30s. If the winds diminish enough there also could be areas of frost...particularly in the typical low- lying locations. The mild spot will be the urban heat Island of Boston where overnight lows should bottom out in the lower 40s. Sunday... A weak ridge of high pressure will be nosing in from the southwest on Sunday...resulting in a mixture of clouds and sunshine. 850T are fairly chilly around -3C...but good mixing on westerly flow should allow for high temps to reach the upper 50s to near 60 in most locations. Westerly winds will gust to between 20 and 25 mph by afternoon. Long Term - Sunday Night Through Friday Highlights * Dry, breezy and mild on Monday and Tue. Elevated fire weather concerns possible. * Shower chances return Wednesday and could linger into Thu. Temps trending colder. * Temps trending milder late in the week into early next weekend. Dry on Fri, but we may turn unsettled over the weekend. Sunday Night through Tuesday... Stuck under persistent cyclonic flow throughout this period. A ridge axis builds from the Mid/Upper Mississippi River Valley Sunday Night into the Great Lakes by early Mon. The ridge builds into the Mid Atlantic by late Monday and offshore on Tue. Another trough digs into the Great Lakes Region by late Tue. High pressure nudges into our region through this period. The high builds overhead Monday Night into early Tuesday before shifting offshore later on Tue. Not a lot of change from the past couple of days. Dry and quiet weather expected through this timeframe. Main concern will be elevated fire weather concerns. For both days the boundary layer will be well mixed, but on Monday flow will be out of the W to NW and on Tuesday winds turn southerly as the high shifts offshore. Both the NAM and GFS (Global Forecast System) continuing to show the boundary layer mixing to approximately 800 hPa per Bufkit soundings. This should mix down the drier air aloft fairly easily. In these situations guidance tends to perform poorly as temps, min RH and dew points overperform. Opted to increase temps to the 75th percentile of guidance for both days. High top out in the mid 50s to the low/mid 60s. Though Tuesday appears to be the milder of the two days given the southerly flow. Lowered dew points/RH values during the daytime due to the excellent mixing to the 10th percentile of guidance for Monday and 25th for Tue. Not as confident in being much drier on Tuesday given the wind shift to southerly flow, which tends to pump a bit more moisture in. At this point have minimum relative humidities of 15 to 35 percent on Monday and 25 to 45 percent on Tue. Could see some 20-25 mph gusts during the day. Tuesday Night through Thursday... Still stuck in cyclonic flow. A trough over the Great Lakes Tuesday Night digs into the eastern Great Lakes/New England on Wed. The trough may lift out of our region by Thu. This will be our next shot for unsettled wet weather as a system slides into our region. A cold frontal system swings through New England mostly on Wednesday bringing widespread rain showers. The PWAT (Precipitable Water) plume not appearing overly impressive with PWATs (Precipitable Waters) below 1 inch per EPS/GEFS and GEPS nil probs of values at or above 1 inch. Deterministic guidance showing we generally we be under roughly 0.75 to 0.85 inches. This is around the 75th percentile for this time of year per Storm Prediction Center Sounding Climo for CHH. We do have a deeper S/SWly low level jet at 850 hPa, which could help squeeze out the moisture available. At this point deterministic guidance shows roughly 30-40 kt jet in place. So we are trending a bit weaker of a system compared to 24 hrs ago. Should remain mild/seasonable on Wed. Temps will be above 0 C as the system is initially moving in, so should stay all rain. However, as things are winding down much colder air may filter in late Wednesday into early Thu. This is especially if the GFS is correct with a deep cutoff parking itself over the area. At this point the GFS is the outlier with the ICON/UKMET/ECMWF (European Centre for Medium-Range Weather Forecasts) and GEM guidance all milder. So, have backed away from snow mixing in as things are winding down. At this juncture we've still got mod to high probs (30-80 percent) of totals at or above 0.1 inches. Whereas the probs of have lowered for 0.5 inches to low (around 10 percent). The best shot is across the interior per GEFS/EPS and GEPS guidance. Still just sticking with WPC for now. High temperatures on Wednesday range from the mid 50s to the low 60s. As for Thu we will be cooler in wake of the system with highs in the low to mid 50s. There could be isolated showers across the interior. Friday through Saturday... Ridge axis builds into the Great Lakes region on Fri and into Sat, but a shortwave may ride the ridge as we head into Sat. High pressure generally in control through this period, but a frontal boundary may lift toward us as we head into the weekend. Dry and quiet weather anticipated with temperatures rebounding nicely as we head into the weekend. Do have some uncertainty as we head into the weekend with that shortwave lifting toward us. Given it is spring time there could be some convective influences. Have just stuck with the NBM for now. Highs around seasonable levels on Fri and slightly warmer than normal on Sat. Marine Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. 06z TAF Today...High Confidence. Conditions deteriorate to low end MVFR-IFR with localized brief LIFR conditions through 12z as showers blossom across the region. The showers should end northwest of I-95 by lunchtime with conditions gradually improving to VFR. Southeast of I-95...the lower conditions will persist until late afternoon and early evening across the Cape/Islands. SW winds becoming more W at 5 to 15 knots as the day wears along with some 20-25 knot gusts developing during the afternoon across the interior. Tonight and Sunday...High Confidence. Any lingering MVFR-IFR conditions across the Cape/Islands dissipate this evening. Otherwise...VFR conditions expected tonight and Sunday. WNW generally 5-10 knots shifting to the WSW Sunday at 10 to 15 knots with some gusts of 20 to 25 knots. KBOS TAF...High Confidence in TAF. KBDL TAF...High Confidence in TAF. Outlook /Sunday Night through Wednesday/... Sunday Night through Monday Night: Winds less than 25 kt. Tuesday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Tuesday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Seas locally approaching 5 ft. Wednesday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of seas approaching 5 ft. Chance of rain showers. Fire Weather Sunday... Dry westerly flow in pre-greenup should allow for elevated fire weather concerns on Sunday. The airmass will mix deeply and allow for a large temp/dewpoint spread. Highs should reach the upper 50s to near 60 with dewpoints dropping into the lower to middle 20s. This should result in minimum afternoon relative humidities between 20 and 30 percent. The deep mixing should also produce some 20 to 25 mph wind gusts with perhaps a few locales approaching 30 mph briefly. NOAA Boston MA Office: Watches - Warnings - Advisories CT...None. MA...None. RI...None. Marine None. |
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