textproduct: Boston / Norton

WHAT HAS CHANGED

Gale watches hoisted for later Wednesday night into Thursday morning for Buzzards Bay, Cape Cod Bay, and Nantucket Sound.

KEY MESSAGES

- Mainly Dry/pleasant today and Wed. Highs in the upper 70s to the lower 80s both days...albeit a bit more humid Wed. - Breezy, warm and humid Wed night into Thu with brief scattered showers possible...but the vast majority of this time will be dry.

- Mainly dry/pleasant with lower humidity Fri into Sat with highs mainly in the 70s. Turning a bit more humid/warmer Sun into Mon.

DISCUSSION

KEY MESSAGE 1...Mainly Dry/pleasant today and Wed. Highs in the upper 70s to the lower 80s both days...albeit a bit more humid Wed.

A ridge of high pressure in place will result in a beautiful day of weather today. A moisture starved northern stream coupled with diurnal heating will result in scattered clouds today, but still expect plenty of sunshine too. While we can not rule out the risk for a brief spot sprinkle/light shower in the afternoon, areal coverage and duration would be so limited it is not worth including in the forecast. High temps will mainly be in the upper 70s to the lower 80s with comfortable humidity levels too. Low temps tonight should drop into the middle 50s to the lower 60s with light/calm winds along with just some scattered to broken mid level cloudiness.

High pressure moves off the mid-Atlantic coast by Wed. Highs will again be in the upper 70s to the lower 80s, but it will be a bit more humid as high pressure moving off the Mid Atlantic coast brings increasing low level moisture. We also do expect a bit of a southwest breeze to develop by mid to late afternoon.

KEY MESSAGE 2...Breezy, warm, and humid Wed night into Thu with brief scattered showers possible...but the vast majority of this time will be dry.

A cold front will approach the region Wed night into early Thu. Out ahead of this front a modest southwest LLJ of 45-50+ knots at 950 mb. This should be enough to result in breezy southwest wind gusts of 20-30 mph with a few gusts of 35-40 mph possible in the vicinity of the upper Cape where they are favored based on soundings and pattern recognition.

As for precipitation chances, precipitable water values will approach 2 inches ahead of the cold front. However, the low level moisture is fairly shallow and only deepens in a narrow band along the cold front and the better dynamics/forcing is across northern New England. Therefore...only expect a brief round of scattered showers with the cold front and the majority of Wed night into Thu will feature dry weather. It will be a humid though and the gusty southwest winds will hold low temps into the 65-70 degree range Wed night. Highs on Thu will be warm for this time of year, mainly in the middle 80s but a few spots may reach the upper 80s and it will be humid.

KEY MESSAGE 3...Mainly dry/pleasant with lower humidity Fri into Sat with highs mainly in the 70s. Turning a bit more humid/warmer Sun into Mon.

Post frontal airmass will result in beautiful weather Fri into Sat with lower humidity. Plenty of sunshine expected both days with highs mainly in the 70s along with comfortable humidity. High pressure overhead will allow for many locations to fall into the 40s to the lower 50s Fri night/Sat am...which may end up being the coolest night for many locations since late last spring.

This high pressure system will shift east of the region by Sun and Mon. This will allow for a return southwest flow of a bit more humid/warmer airmass to work back into the region.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

Forecaster Confidence Levels...

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

18z TAF Update...

Through 00z...High confidence.

VFR, despite an increase in some mid level cloudiness. NW winds 5-10 knots, except sea breezes developing along portions of the immediate coast this afternoon, between 19-21z.

Tonight...High confidence.

VFR. Calm/light E winds.

Wednesday...High confidence.

VFR. SW wind gusts of 15-25 knots developing during the afternoon.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Wednesday Night through Sunday/...

Wednesday Night: VFR. Windy with gusts up to 35 kt. Chance SHRA.

Thursday: VFR. Strong winds with local gusts up to 40 kt. Chance SHRA.

Thursday Night through Friday: VFR. Breezy.

Friday Night through Saturday: VFR.

MARINE

Forecaster Confidence Levels...

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

Today through Wednesday...High confidence.

High pressure in control will keep winds/seas well below Small Craft Advisory criteria today and tonight. This high moves off the Mid Atlantic coast Wed, which will allow for increasing SW winds. We expect SW wind gusts of 20-25 knots to develop by mid to late Wed afternoon. We should see widespread SW wind gusts of 25 to 35 knots Wed night into Thu morning with a fairly strong LLJ down to 950 mb. For now will have hoisted Gale Watches for Buzzards and Cape Cod Bays as well as Nantucket sound...which tend to blow the hardest in these setups. Later shifts may need to expand these Gale Watches. At the very least, we will need Small Craft Advisories for all waters over this time.

Outlook /Wednesday Night through Sunday/...

Wednesday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Local rough seas. Chance of rain showers.

Thursday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Rough seas up to 9 ft. Chance of rain showers.

Thursday Night: Low risk for Small Craft Advisory winds with local gusts up to 30 kt. Local rough seas. Chance of rain showers.

Friday: Winds less than 25 kt. Areas of seas approaching 5 ft.

Friday Night through Saturday: Winds less than 25 kt.

BOX WATCHES/WARNINGS/ADVISORIES

CT...None. MA...None. RI...None. MARINE...Gale Watch from Wednesday evening through Thursday morning for ANZ231>234.