textproduct: Boston / Norton

WHAT HAS CHANGED

No major changes.

KEY MESSAGES

- Soggy and cool Sunday, steady moderate rain in all areas and localized downpours possible, especially the RI/MA South Coast. Rain pulls offshore Sunday night with slow warming, but with areas of fog and drizzle into Monday morning.

- Wet to start Memorial Day, drying out later in the day. Above normal temperatures for the middle of next week before trending closer to normal late next week. A couple periods of showers possible but no washouts expected.

DISCUSSION

KEY MESSAGE 1...Soggy and cool Sunday, steady moderate rain in all areas and localized downpours possible, especially the RI/MA South Coast. Rain pulls offshore Sunday night with slow warming, but with areas of fog and drizzle into Monday morning.

After a marathon wait for the rain seemingly on our doorstep to arrive, it has finally reached all the way to eastern MA. Don't expect a different story for roughly the next 24 to 36 hours. The much advertised anomolous plume of moisture featuring PWATs near 1.75" (99th percentile of normal) is squarely overhead coincident with a 40-45 kt LLJ and associated moisture convergence. Thus, expecting a widespread rainfall to continue, at times moderate to heavy especially over the south coast of RI and southeast MA. While the HREF PMM has backed off significantly on the wettest scenario we continue to expect 1 to 2 inches of rain before the drier air finally funnels in on W/NW flow as the trough axis passes on Monday.

KEY MESSAGE 2...Wet to start Memorial Day, drying out later in the day. Above normal temperatures for the middle of next week before trending closer to normal late next week. A couple periods of showers possible but no washouts expected.

As for Memorial Day, well, best I can say is it could be worse. As mentioned by the previous forecaster, warm advection overnight will lead to warming temperatures back into the 70s on Monday. Compared to upper 40s and 50s on Sunday it will feel downright balmy! Unfortunately as we've gotten into the range of the hi-res guidance we've gotten a better hold on the timing of the back edge of the moisture (read: rain showers) and while those in western MA may be done with the showers by late morning, those in eastern MA will likely be dealing with them until closer to mid or late afternoon. Most everyone, though, should (given our late sunsets) end the day with dry weather at least, if not some good breaks of sun through high clouds. Nice sunset alert, perhaps?

Guidance continues to indicate a nice day on Tuesday with strong warm advection and more sun under weak high pressure. The zonal mid- level flow may extend into Wednesday which would allow temps to once again rise, well into the 80s, before steering flow becomes much more meridional. SNE will be sandwiched between a Bermuda High and a cutoff low over southeast Canada which sends several disturbances around the base of the broader trough over the northeast mid to late week. Difficult to time these periodic bouts of unsettled weather at this distance in time, but the pattern says cooler temperatures (closer to normal for late May) and periods of wet weather intermixed.

AVIATION /06Z SUNDAY THROUGH THURSDAY/

Forecaster Confidence Levels...

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

06Z update...

Through 12Z: High confidence in TAF/trends, but moderate on timing.

VFR to start with -RA. GIGS deteriorate to MVFR for BDL by 08Z. MVFR visibility in RA. SE winds increasing to around 8-12 kt.

Sunday: Moderate confidence.

MVFR/MVFR cigs to start, deteriorating to IFR in steady light to moderate rain with visibilities 3-5 SM. Localized downpours mainly for TAFs S/E of I-95 in the afternoon. SE winds around 10-15 kt with gusts 20-25 kt, becoming E/ENE for the eastern TAFs in the afternoon.

Sunday Night: Moderate confidence.

IFR in steady rain moving off the east coast around 03-06z. Clearing of steadier rain then brings widespread IFR- LIFR with drizzle, mist and fog with light NE winds.

Monday: High confidence in trends. Moderate confidence in timing.

IFR/LIFR to start in SHRA, ending from west to east between 15Z and 21Z with improvement to VFR. SW winds become NW 5-10 kts.

KBOS...High confidence in TAF.

KBDL...High confidence in TAF.

Outlook /Monday Night through Thursday/...

Monday Night through Tuesday Night: VFR.

Wednesday: VFR. Breezy. Slight chance SHRA, slight chance TSRA.

Wednesday Night through Thursday: VFR. Slight chance SHRA.

MARINE

Forecaster Confidence Levels...

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

SCAs in effect on most waters with SE winds 15-25 kt early this morning, then increasing to 25-30 kt during the day. Seas will be building to 6 to 10 ft today into tonight. Areas of rain will reduce visibility to around 3 miles.

Rain moves offshore early tonight, with winds easing and becoming ESE to S around 10-15 kt. Seas will still remain elevated at 5-7 ft through Sunday night, thus SCAs continue into most of Monday to allow for seas to subside. Although rain comes to an end, fog and drizzle is likely to develop Sunday night on the waters, with locally dense fog possible.

Outlook /Monday Night through Thursday/...

Memorial Day: Winds less than 25 kt. Rough seas up to 9 ft. Chance of rain showers.

Monday Night: Winds less than 25 kt. Seas up to 5 ft. Slight chance of rain showers.

Tuesday: Winds less than 25 kt. Seas up to 5 ft.

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

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

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

BOX WATCHES/WARNINGS/ADVISORIES

CT...None. MA...None. RI...None. MARINE...Small Craft Advisory from 5 AM early this morning to 2 AM EDT Monday for ANZ231. Small Craft Advisory until 5 AM EDT Monday for ANZ232>235-237. Small Craft Advisory from 5 PM this afternoon to 8 PM EDT Monday for ANZ250. Small Craft Advisory until 8 PM EDT Monday for ANZ254>256.