Area Forecast Discussion

WHAT HAS CHANGED

No significant changes to the forecast since the last update.

KEY MESSAGES

- Unseasonable warmth and dry weather continues today

- Wet and unsettled weather returns Thursday into this weekend. Continued above normal temperatures before cooler conditions arrive Sunday and beyond.

DISCUSSION

KEY MESSAGE 1...Unseasonable warmth and dry weather continues today

Not much change to the overall synoptic pattern, High pressure over the North Atlantic will maintain steady south to southwest winds. Will continue to favor the warmest temperature guidance today since temperatures did not lower much overnight. Both the REFS and NBM had rather high probabilities for max temperatures to be 15-20 degrees above normal today, especially across eastern MA as well as the CT River valley. Some record high temperatures could be met or broken. Record at BOS is 78, PVD 77, ORH 74, BDL 78.

A warm day will be followed by another warm night. Overnight temperatures fall into the 50s which is about average for our high temperatures this time of year. Some locations may have a shot at meeting/breaking the high min record.

KEY MESSAGE 2...Wet and unsettled weather returns Thursday into this weekend. Continued above normal temperatures before cooler conditions arrive Sunday and beyond.

Ensemble guidance continues to herald the end of our highly anomalous stretch of dry weather by Thursday, kicking off a period of 36-48 hours of periodic rainfall, sometimes heavy. This comes courtesy of a few things; first is an approaching front extending from a trough of low pressure crossing the Great Lakes. After moving through NY state, this front stalls across New England from SW to NE late Thursday. This brings an initial round of rain chances for Thursday, mainly for western areas of SNE, while much of the region southeast of a BDL-ORH line may remain dry. A more widespread and heavier rainfall should then arrive for Friday into early Saturday as a secondary low pressure forms along this front. It deepens as it lifts north in the vicinity of Cape Cod Saturday, and then even moreso over the Gulf of Maine on Sunday, by which time we'll be on the drier side.

There will be a lot of moisture for this system to work with as persistent moist SW flow ahead of the upper trough pulls in PWATs over 1.5" and dewpoints into the lower 60s! This will lead to very warm conditions Friday morning (in the lower 60s) but more importantly, fuel for the good dynamics to work with. These elevated dewpoints will generate some instability, allowing for some convection to contribute to localized downpours, while convergence around the low and placement beneath the RRQ of a 105kt upper jet will provide more lift in the meso/synoptic scale.

The exact placement of the swath of heaviest rainfall will unfortunately not be nailed down until we get closer to this event as it will be determined by where exactly this front stalls. Generally ensemble guidance is calling for a 1-3" rainfall, with EPS and GEFS calling for a 50-60% and 30-40% chance of 1" or greater rainfall respectively, centered over central and eastern SNE. Fortunately, we've been very dry and flash flood guidance is high. Thus, not expecting flash flooding to be an issue though some poor drainage/urban flooding is possible especially given the leaves blocking drainage this time of year. There is a marginal risk within the Excessive Rainfall Outlook for Friday into Saturday.

Beyond Saturday, we'll see some scattered showers continuing as the upper trough is slow to exit overhead; nothing like Friday/Saturday though. NW flow ushers in a colder, albeit closer to normal, airmass for early next week with high temperatures returning to the 50s.

AVIATION /07Z WEDNESDAY THROUGH SUNDAY/

Forecaster Confidence Levels...

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

Today...High confidence.

VFR. SCT higher decks possible during the day. Areas of lower FEW/SCT cloud decks can't be ruled out along the south coast/Cape terminals. Winds SSW/SW at 5-15 kts. Few gusts to 18-20 kts for ORH and coastal terminals this afternoon.

Tonight...Moderate confidence.

Initially VFR, likely falling to MVFR and IFR after 06z due to lower ceilings. Areas along could see reduced visbys to MVFR/IFR levels earlier in the overnight period, but these could exit after 06z. S to SSW winds overnight at 5-10 kt, with some areas in the higher elevations seeing occasional 18 kt gusts after 06z.

Thursday...Moderate confidence.

Areas of MVFR and IFR to start. Slow improvement to VFR from SE to NW. IFR could linger across the higher terrain of central and western MA into evening.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Thursday Night through Sunday/...

Thursday Night: Mainly VFR, with local IFR possible. Breezy. Chance RA.

Friday: MVFR/IFR conditions possible. RA, slight chance TSRA.

Friday Night: Mainly MVFR, with local IFR possible. RA, slight chance TSRA.

Saturday: Mainly VFR, with local MVFR possible. Chance RA.

Saturday Night: Mainly VFR, with local MVFR possible. Breezy. Slight chance RA.

Sunday: VFR. Breezy. Slight chance RA.

MARINE

Forecaster Confidence Levels...

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

Through Thursday...High confidence.

Surface high pressure stays positioned SE of the waters into Thursday. Winds become breezy by this afternoon with 20 kt gusts. A few gusts up to 20-25 kts are possible, with the greatest chance for the SE coastal waters near the Cape/Islands. Gusts likely aren't consistent enough 25kt+ over a period to warrant Small Craft Advisories at this time.

Outlook /Thursday Night through Sunday/...

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

Friday: Winds less than 25 kt. Seas up to 5 ft. Rain, slight chance of thunderstorms.

Friday Night: Winds less than 25 kt. Local rough seas. Rain, slight chance of thunderstorms. Local visibility 1 to 3 nm.

Saturday: Winds less than 25 kt. Seas up to 5 ft. Chance of rain, slight chance of thunderstorms.

Saturday Night through Sunday: Winds less than 25 kt. Seas up to 5 ft. Slight chance of rain.

CLIMATE

Persistent unseasonable warmth over the next several day will challenge calendar-day record highs and record high minimums across southern New England climate sites.

Daily Record Highs to Watch:

Boston (BOS): Wednesday 78F (1987)|Thursday 79F (1994)

Hartford/Bradley (BDL): Wednesday 78F (1987)|Thursday 75F (2022)

Providence (PVD): Wednesday 77F (1987)|Thursday 75F (1994)

Worcester (ORH): Wednesday 74F (1987)|Thursday 73F (1994)

Daily Record Lows to Watch:

Boston (BOS): Thursday 56F (1994)|Friday 57F (2020)

Hartford/Bradley (BDL): Thursday 55F (1994)|Friday 56F (2020)

Providence (PVD): Thursday 56F (1994)|Friday 58F (2020)

Worcester (ORH): Thursday 55F (1994)| 55F (2020)

BOX WATCHES / WARNINGS / ADVISORIES

CT...None. MA...None. RI...None. MARINE...None.