Marine Weather and Tide Forecast for Glastonbury Center, CT

NEAR TERM /UNTIL 6 PM THIS EVENING/
945 AM update...

No changes to the current forecast. Area of heavy rain lifting north along the south coast will continue to move northward across SNE this morning. Still looking at the peak of the rain and wind occurring mid afternoon through early evening. Strong signal in the HRRR with enhanced probs of > 1" in 3 hours across RI and eastern MA. Expecting 1-2" of rainfall in a 6 hour period this afternoon and evening at the nose of the easterly low level jet as it lifts north across the region. This will impact the evening commute with areas of urban and poor drainage street flooding. Strongest winds also during this time with peak gusts to 55 mph possible over the Cape/Islands, 40-50 mph gusts along the immediate eastern MA coast, and 30-40 mph gusts along the I-95 corridor.

Previous discussion...

Key Messages:

* Widespread rain arrives this morning and becomes heavy during the afternoon/eve with nuisance street flooding possible

* ENE wind gusts of 40-50+ mph along the coast with pockets of minor coastal flooding during the evening high tide.

* Unseasonably cool with highs mainly in the 40s

Not much change to the ongoing forecast for today. Expecting a low pressure to approach southern New England from the south towards this evening. While the center of this low pressure should remain near Nantucket and the outer Cape, Rainfall will reach farther inland. Still thinking the heaviest rainfall will be across the eastern half of southern New England. It appears than most of our region should receive total rainfall of 1-2 inches through daybreak Friday. HRRR LPMM had peak totals closer to 3 inches in spots towards the east coast of MA, which appeared reasonable.

Given the duration of this storm, not anticipating any flash flooding. Poor drainage and urban flooding is more likely at the most susceptible spots. We may need to keep an eye on area rivers though, especially some of the smaller ones. Will need to see exactly where the heaviest rainfall occurs and how quickly it falls. This should be a soaking rainfall, which will only help alleviate some of the dryness we have across southern New England.

Besides the rainfall, there is a concern for some minor wind impacts. A potent low level jet (3-4 standard deviations above normal) will provide the momentum for some gusty winds. A Wind Advisory remains in effect for the eastern MA coast. Gusts as high as 45-55 mph are possible on Cape Cod and the islands, with gusts up to 50 mph for the rest of the east coast. Gale Warnings also remain in effect for all MA and RI coastal waters.

A Coastal Flood Advisory continues along the coast for low-end minor flooding potential with the evening high tide, when some erosion and minor splashover is possible. Fortunately, astronomical tides are on the lower side, which saves us from much bigger problems that would have arisen.

Overall, the main impacts from this system still looks to be within a 12-hour period from noon to midnight.

SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/
Low pressure should pass near Nantucket and the outer Cape tonight, reaching the Gulf of Maine for Friday. The majority of the rainfall and wind impacts should be before midnight, although some lingering showers are possible towards northeast MA. Winds will remain elevated longer across the eastern MA coastal waters. This low pressure will move farther from our region Friday, but still keep enough cyclonic flow across our region where scattered showers remain a possibility, especially during the afternoon hours.

LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/
Key Messages:

* Unseasonably cool Sat with a few showers, but not a washout * Mainly dry Sun/Mon & with many locales breaking 70 by Mon * A few showers Tue night/Wed if a low tracks far enough north * Despite moderating temps they will remain a tad below normal

Details...

Saturday...

Anomalous closed upper level low will still be spinning in the vicinity of Maine and the Canadian Maritime on Sat. Cyclonic flow around this system will result in at least a scattered to broken deck of clouds with a few passing showers. However, the majority of the day will be dry but just unseasonably cool.
850T are only around 0C...so while some peeks of sunshine will likely occur high temps will mainly be in the upper 50s to near 60.

Sunday and Monday...

The closed upper level low that has been controlling our weather will finally lift northeast of the Canada Maritimes Sun and Mon.
At the same time, a ridge of high pressure will build in from the west. The result will be mainly dry weather and moderating temps. Highs should reach into the 60s on Sun and probably breaking 70 in spots on Monday /Memorial Day/.

Tuesday into Wednesday...

The next shortwave trough and its associated low pressure system will be approaching from the west by the middle of next week.
However, northern stream energy may try to force the deeper moisture and forcing south of our region. So while we may see a few showers Tue night/Wed...a lot of the guidance suggests this system may be a glancing blow/miss. It is way too early though to lock anything in and will just have to see how the models trend over the next few days. The high temperatures Tue and Wed will depend on the above, so thinking most likely outcome are highs in the middle 60s to the lower 70s. Certainly a big improvement from what we will experience the next few days, but temperatures still likely to average a bit below normal into the middle of next week.

AVIATION /18Z THURSDAY THROUGH TUESDAY/
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.

18z TAFs: Overall high confidence in trends, but some uncertainty in timing.

MVFR conditions in rain and fog will give way to more widespread IFR conditions as we head through late afternoon and into tonight. Potential for embedded TS near the south coast, especially on Cape Cod and the Islands through late afternoon.
E/NE winds gust to 30kt inland and to 40-45kt along coast. In addition, LLWS expected near ACK due to 40-50kt winds at 020.

Slow improvement late tonight into Friday as rain ends from southwest to northeast, but MVFR/IFR ceilings are likely to persist.

BOS TAF...High confidence.

BDL TAF...High confidence.

Outlook /Friday Night through Tuesday/...

Friday Night: Mainly MVFR, with local IFR possible. Chance SHRA.

Saturday: Mainly MVFR, with local IFR possible. Breezy. Chance SHRA.

Saturday Night: Mainly VFR, with areas MVFR possible. Slight chance SHRA.

Sunday: Mainly VFR, with local MVFR possible. Breezy.

Sunday Night through Monday Night: VFR.

Tuesday: Mainly VFR, with areas MVFR possible. Slight chance SHRA.

MARINE
Forecaster Confidence Levels:

Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.

Through Friday: High confidence.

Rain arrives across the southern coastal waters early this morning, and across the eastern coastal waters by mid morning.
Poor visibility in moderate to heavy rainfall at times. Increasing winds as a low pressure moves across the waters late today into tonight. A Gale Warning remains in effect for all waters for 35-45 kts with seas 6-10 ft. Winds and seas slowly begin to diminish through tonight into Friday.

Outlook /Friday Night through Tuesday/...

Friday Night: Winds less than 25 kt. Seas up to 5 ft. Chance of rain showers.

Saturday: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers.

Saturday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Slight chance of rain showers.

Sunday through Monday Night: Winds less than 25 kt.

Tuesday: Winds less than 25 kt. Slight chance of rain showers.

BOX WATCHES/WARNINGS/ADVISORIES
CT...None.
MA...Wind Advisory until 11 PM EDT this evening for MAZ007-015-016- 019.
Coastal Flood Advisory from 6 PM to 11 PM EDT this evening for MAZ007-015-016-019-022>024.
Coastal Flood Advisory from 4 PM this afternoon to 7 PM EDT this evening for MAZ020-021.
Wind Advisory until 11 PM EDT this evening for MAZ022>024.
RI...Coastal Flood Advisory from 4 PM this afternoon to 7 PM EDT this evening for RIZ006>008.
MARINE...Gale Warning until 1 AM EDT Friday for ANZ230.
Gale Warning until 11 PM EDT this evening for ANZ231>235-237.
Gale Warning until 11 PM EDT this evening for ANZ236.
Gale Warning until 7 AM EDT Friday for ANZ250-251.
Gale Warning until 1 AM EDT Friday for ANZ254>256.