Rhode Island Sound Marine Forecast
|Rest Of Tonight...Sw Winds Around 10 Kt. Seas Around 2 Ft.|
|Fri...Sw Winds 5 To 10 Kt. Seas 2 To 3 Ft.|
|Fri Night...Sw Winds 5 To 10 Kt. Seas 2 To 3 Ft.|
|Sat...S Winds 5 To 10 Kt. Seas 2 To 3 Ft.|
|Sat Night And Sun...S Winds 10 To 15 Kt. Seas Around 2 Ft.|
|Sun Night...S Winds 10 To 15 Kt. Seas 2 To 4 Ft. A Chance Of Showers.|
|Mon And Mon Night...S Winds 10 To 15 Kt. Seas 2 To 4 Ft. A Chance Of Showers.|
|Tue...S Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas 3 To 5 Ft. A Chance Of Showers.|
|Tue Night...S Winds Around 15 Kt With Gusts Up To 20 Kt. Seas 4 To 7 Ft. A Chance Of Showers. 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
1002pm EDT Thu September 24 2020
Quiet and dry weather, courtesy of high pressure, will continue to round out the work week. This weekend will be mainly dry, although there is a slight chance of showers. Early next week will feature increasingly moist southerly flow out ahead of a cold front, which arrives late Tuesday into Wednesday. There will be chances of showers each day, but greatest with the front itself. Temperatures will be near or a little above normal.
Near Term - Until 6am Friday Morning
Thick cirrus cloud shield continued to move eastward late this evening. Some models attempt to develop a few low clouds over Nantucket overnight. Otherwise, no major changes to the forecast with this update package.
Previous discussion... High pressure off of the east coast continues to rule the forecast for southern New England. High cirrus clouds filtered in early this afternoon leaving us with a milky white/overcast appearance. Tonight we expect mild conditions, once again. Across interior Massachusetts temperatures drop to the low 50s and elsewhere morning temperatures are in the middle and upper 50s.
Short Term - 6am Friday Morning Through Friday Night
Another dry day ahead, high pressure continues to influence our forecast with mainly clear skies. Though the sky will have more clouds further north as a quasi stationary boundary extends across southern Vermont and southern New Hampshire. Guidance supports a backing southwest wind during the morning hours - before becoming south southeast during the early afternoon. Temperature trends continue right into Friday with afternoon temperatures climbing into the upper 70s and lower 80 degree range. The quiet trend extends through Friday evening and early Saturday.
Long Term - Saturday Through Thursday
Highlights... * Increasingly moist southerly flow early next week, which brings chances of showers ahead of a cold front, which arrives late Tuesday or Wednesday.
Details... Saturday and Sunday... A rather nondescript weather pattern exists over our region this weekend. Weak high pressure will remain to our northeast while weak low pressure passes well to our south and southeast. It looks like there will be a bit of an increase in precipitable water values aloft...to about 1.2 inches...in association with remnants of Beta. But there is no real trigger for precipitation. Skies will be partly cloudy, with more cloud cover on Sunday than Saturday. Cannot rule out a slight chance of a shower, with southerly flow increasing dewpoints from upper 50s Saturday morning to the mid 60s by Sunday afternoon. Highs will be a little above normal...mainly 75 to 80 across the interior.
Sunday night through Monday night... The GFS hints at a bit of an instability burst in RI and eastern MA Sunday night with K Indices reaching 34. Dewpoints will be in the lower to mid 60s across the region. There is a chance of showers Sunday night. The chance of showers continues Monday into Monday night, as an upper level disturbance passes through. We are not talking about washouts...and certainly no drought- reducing rainfall. Highs Monday will again be in the mid and upper 70s across the interior.
Tuesday into Wednesday... A very anomalous deep trough develops in Midwest, moving into the Ohio Valley. Southerly flow becomes a bit gusty over southern New England, with gusts to 15-25 mph. On Tuesday night into early Wednesday, the trough becomes slightly negatively tilted and a 140-160 kt jet at 250 mb advances toward New England. At the surface a cold front will be slowly advancing across New York state. The GFS is much faster, with the front moving through on Tuesday night. The ECMWF (European Centre for Medium-Range Weather Forecasts) is significantly slower, with the front coming through on Wednesday. At some point, most likely Tuesday evening, a southerly low level jet of 60-70 knots at 850 mb moves across southern New England. There is about 500-1000 Joules of CAPE forecast with 0-1km helicity values in the 200-300 range in the slopes of the Berkshires and CT River valley. Have introduced a slight chance of thunderstorms for those areas Tuesday afternoon and Tuesday night. While it is way too far in advance to predict severe weather, this pattern is one that could produce it, especially to our southwest...something to watch for in the days ahead.
The showers with this front have the potential to produce locally heavy rainfall. This is our best shot at places receiving any significant rainfall.
Thursday... There is a significant discrepancy amongst the models for Thursday. The ECMWF develops a closed low over the southern states that lifts northeast over New England, producing low pressure at the surface and rainy conditions. Right now, we are sticking with the consensus of other models which have a dry day in the wake of the departed cold front.
So, for now, mainly sunny skies are forecast, with dewpoints dropping into the comfortable upper 40s and 50s and more seasonable high temperatures...in the upper 60s to lower 70s.
Relatively light winds and seas are expected through Friday night, with high pressure centered south of the waters.
Outlook /Saturday through Tuesday/... Saturday through Sunday: Winds less than 25 kt.
Sunday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain showers.
Monday through Monday Night: Winds less than 25 kt. Seas up to 5 ft. Chance of rain showers.
Tuesday: Winds less than 25 kt. Areas of rough seas. Chance of rain showers.
NOAA Boston MA Office: Watches - Warnings - Advisories
CT...None. MA...None. RI...None. MARINE...None.