textproduct: Boston / Norton

WHAT HAS CHANGED

Small craft advisories and gale watches issued for our coastal waters late tonight and Monday. Confidence continues to increase in well above normal summer-like warmth for much of the work week...at least away from the immediate coast.

KEY MESSAGES

- Dry weather today with highs in the 50s to near 60...but cooler upper 40s to lower 50s on parts of the immediate coast. A few showers tonight...mainly across northern MA. Gusty southerly winds develop toward daybreak Mon.

- Summer-like warmth much of the work week with highs in the 70s and 80s at least away from the immediate coast. A few showers and thunderstorms are possible at times, but dry weather dominates.

DISCUSSION

KEY MESSAGE 1...Dry weather today with highs in the 50s to near 60...but cooler upper 40s to lower 50s on parts of the immediate coast. A few showers tonight...mainly across northern MA. Gusty southerly winds develop toward daybreak Mon.

Large high pressure gradually shifts east of the region today. This will result in seasonable/pleasant weather to close out the weekend...But with much less wind than yesterday. Plenty of sunshine is also expected this morning...but we should see mid-high level cloudiness increase and thicken this afternoon out ahead of an approaching shortwave. High temperatures today will mainly be in the 50s to perhaps near 60 in spots...but cooler upper 40s to the lower 50s are expected along parts of the immediate coast with sea breezes.

A warm front and associated shortwave energy crosses the region tonight. The deeper moisture and stronger forcing will be located to our north across northern New England where the bulk of the showers will reside. Nonetheless...a few showers are expected tonight mainly across northern MA closer to the better forcing. Any rainfall amounts though should be rather light. Low temperatures will be in the 40s...but many locations will rise to around 50+ toward daybreak Mon as warm advection increases. In fact...a 45 to 55+ knot southwest LLJ will result in gusty southwest winds developing toward daybreak.

KEY MESSAGE 2...Summer-like warmth much of the work week with highs in the 70s and 80s at least away from the immediate coast. A few showers and thunderstorms are possible at times, but dry weather dominates.

All of our model guidance continues to support well above normal temperatures for most of the work week. On Monday...strong warm advection aloft/southwest LLJ will result in a lot of clouds, gusty southwest winds and the risk for a few showers at times. High temps will mainly be in the 60s to the lower 70s...but cooler along the south coast given gusty southwest winds.

The real warmth looks to arrive Tue and continue for the rest of the work week. A strong upper level ridge over the Gulf of Mexico will result in well above normal height fields across the region. This should yield high temps in the 70s and 80s for the rest of the work week...At least away from the immediate coast. We will have to watch for a backdoor cold front lurking to our north. Most of the guidance keeps it generally north of us during the work week except for areas near the eastern MA coast...where temps could be noticeably cooler for a day or two than the rest of the region. We also should mention that sometimes these backdoor cold fronts end up further south than the global guidance suggests...so this will be one potential fly in the ointment. Again right now thinking outside the immediate coast...odds favor summerlike warmth for the rest of the week. But given our climatology...still a bit cautious until we get into more of the high resolution CAMs which handle these situations better.

While much of the upcoming week will be dry...there will be the risk for a few showers/t-storms at times. Westerly flow aloft coupled with an anomalous airmass in place will result in this potential especially during the afternoon/evening hours. That being said...timing of any shortwaves in westerly flow aloft is often difficult. Just something to keep in mind. FWIW...the CSU machine learning probs do even has some low severe probs across the region on Tue.

AVIATION /07Z SUNDAY THROUGH THURSDAY/

Forecaster Confidence Levels...

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

06z TAF Update...High confidence.

Mainly VFR conditions continue today through Monday. A few showers tonight mainly across northern MA may result in briefly lower/localized conditions. We also should see MVFR-IFR conditions in low clouds and fog patches develop near the south coast during the day Monday as high dewpoint air begins to work over the relatively cold ocean.

Light and variable winds early this morning become S at 6-12 knots this afternoon...but with localized sea breezes developing along parts of the immediate coast. SW winds will increase very late tonight and especially Monday with gusts of 20 to 30 knots expected...strongest of which will be near the south coast. In fact...we may see southwest wind gusts near 35 knots in the vicinity of KFMH given pattern recognition.

KBOS Terminal... High confidence in TAF. Sea breeze should develop by 14z this morning.

KBDL Terminal... High confidence in TAF.

Outlook /Monday Night through Thursday/...

Monday Night: VFR. Breezy.

Tuesday through Tuesday Night: VFR. Breezy. Scattered SHRA.

Wednesday through Wednesday Night: VFR. Chance SHRA, slight chance TSRA.

Thursday: VFR. Chance SHRA.

MARINE

Forecaster Confidence Levels...

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

Today through Monday...High confidence.

Winds/seas will remain below small craft advisory thresholds today. However...a strengthening LLJ very late tonight and especially Monday will result in SW wind gusts of 25 to 30+ knots over all the waters and potentially some nearshore 35 knot gusts in the climatologically favorable locations in this setup near Buzzards/Cape Cod Bays as well as Block Island and Nantucket sounds. Therefore...we opted to issue a Gale Watch for those waters on Monday. Lastly...will need to watch for the development of fog across the southern waters on Monday as high dewpoint air advects northward over the relatively cold ocean.

Outlook /Monday Night through Thursday/...

Monday Night: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Slight chance of rain showers.

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

Tuesday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Isolated rain showers.

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

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

Thursday: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain showers.

BOX WATCHES/WARNINGS/ADVISORIES

CT...None. MA...None. RI...None. MARINE...Small Craft Advisory from 2 AM to 8 PM EDT Monday for ANZ230- 236. Gale Watch from Monday morning through Monday afternoon for ANZ231>234. Small Craft Advisory from 2 AM Monday to 5 AM EDT Tuesday for ANZ235-237. Small Craft Advisory from 10 PM this evening to 2 AM EDT Tuesday for ANZ250-251. Small Craft Advisory from 2 AM Monday to 8 AM EDT Tuesday for ANZ254>256.