Lexington, Massachusetts, USA
000
FXUS61 KBOX 051819
AFDBOX
Area Forecast Discussion
National Weather Service Boston/Norton MA
219 PM EDT Fri Jun 5 2026
.WHAT HAS CHANGED...
Continue to refine summery temperatures and timing of
precipitation along with the risk for thunderstorms (some could
be severe) for this coming weekend.
&&
.KEY MESSAGES...
- Unseasonably warm to hot temperatures continue today and
Saturday with dry weather persisting.
- Increasing risk for showers and a few strong to severe
thunderstorms Saturday evening. Sunday trends somewhat warmer
with periods of showers and possible thundershowers.
- Dry and cooler conditions return early next week with onshore
flow, before temperatures trend more summerlike by midweek.
&&
.DISCUSSION...
KEY MESSAGE 1...Unseasonably warm to hot temperatures continue today
and Saturday with dry weather persisting.
There are no notable changes to the near and short-term forecast
through the daylight hours of Saturday. Confidence remains high that
dry weather continues along with unseasonably warm to hot
temperatures. As advertised over the past several days, the primary
weather feature remains an area of high pressure centered across the
southeastern CONUS, which slowly shifts offshore this weekend ahead
of more unsettled conditions. Little has changed regarding
temperatures aloft, with 850 mb values remaining between +13C and
+15C Friday and increasing to +15C to +18C Saturday. Given a well-
mixed boundary layer reaching 850-800 mb, highs should climb well
into the upper 80s to lower 90s. While temperatures aloft are warmer
Saturday, increasing moisture and cloud cover may temper daytime
heating somewhat. Nevertheless, temperatures remain well above
normal for early June, when average highs are typically in the lower
70s. A more westerly wind today should allow coastal communities to
warm efficiently, while stronger southwest flow Saturday keeps
southern coastal areas somewhat cooler, generally in the upper 70s
to lower 80s. Dewpoints remain comfortable today in the 50s but rise
into the upper 50s to lower 60s Saturday, leading to a somewhat
muggier feel, though not overly oppressive.
For those heading to the beaches, there is a moderate risk for rip
currents Saturday along east-facing beaches of Cape Cod, ocean-
facing beaches of Nantucket and Marthas Vineyard, and south-facing
beaches from Point Judith, RI to Westport, MA. Always check with
lifeguards regarding local rip current conditions.
KEY MESSAGE 2...Increasing risk for showers and a few strong to
severe thunderstorms Saturday evening. Sunday trends somewhat warmer
with periods of showers and possible thundershowers.
Confidence continues to increase that most, if not all, of the
daylight hours Saturday remain dry, though a brief afternoon shower
cannot be ruled out north and west of the I-91 corridor, likely
associated with a prefrontal trough. Increasing heat and humidity
will lead to a moderately unstable atmosphere, with CAPE values
between 500-1000 J/kg, though some guidance suggests locally higher
values approaching 1500 J/kg. This should support convective
initiation by late afternoon, though activity may hold together
after sunset given modest mid-level lapse rates around 6.5-7.5 C/km.
The better wind shear arrives Saturday evening, with 0-6 km bulk
shear increasing to around 30-40 kt. Given this setup, a marginal
risk for severe thunderstorms has been introduced for southern New
England, with the primary threats being strong to damaging straight-
line winds and locally heavy downpours as PWAT values climb to
around 1.8 inches. CAM guidance is beginning to resolve this
timeframe, though refinement in storm timing and placement is still
expected.
By Sunday morning, weak subsidence behind the front may allow for
drier, albeit humid, conditions with a mix of clouds and sunshine.
By afternoon, a more defined mid-level trough and associated
shortwave energy move across southern New England, though recent
guidance trends the surface low farther north into the Gulf of
Maine. As a result, rainfall appears more showery and less
widespread, with the greatest concentration of showers and general
thunder across eastern portions of southern New England. Cooler air
arrives more gradually, which may allow highs to still reach the
upper 70s to lower 80s before northeast flow develops later in the
day.
KEY MESSAGE 3...Dry and cooler conditions return early next week
with onshore flow, before temperatures trend more summerlike by
midweek.
Conditions trend drier and cooler Monday, though some uncertainty
remains regarding how quickly lingering troughing departs, which
will influence temperatures and cloud cover. For now, expect cooler
conditions Monday with a warming trend returning Tuesday into the
middle of next week as temperatures return into the 80s. High
pressure appears likely to return by Tuesday, supporting mainly dry
weather through midweek.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
18z TAF Update:
Through Tonight: High confidence.
VFR. W/WNW winds around 10 kt, though seabreeze for eastern MA
coast should develop by 20z. Winds tonight turn light SW with
ENE winds for NE MA/BOS.
Saturday: High confidence.
VFR for most of the time, although the risk for isolated to
scattered thunderstorms increases after 21z from ORH westward.
Some storms could turn strong with gusty winds leading to local
turbulence being the main risk. A greater storm coverage is more
likely after 00z eastward. Winds become SW and increase to
around 10-12 kt with gusts 20-25 kt.
Saturday Night: Moderate confidence.
VFR outside of scattered thunderstorms which could bring local
IFR visby restrictions. Initial widely scattered storms should
turn into a broken line of storms moving eastward into the
ORH-BED-BOS-PVD corridor between 00-03z, then move offshore. A
couple storms could still be strong early with localized gusty
winds, but general weakening trends are more likely. Brief
clearing between 04-08z north to south as front moves offshore.
SW winds around 10 kt then shift to W/WNW 5-10 kt.
Sunday: High confidence in trends but moderate on timing.
VFR initially, though SHRA/TS develops as soon as 16z Sunday in
the MA/VT/NH border area and progresses south/southeast.
SHRA/TS could be greater in coverage compared to Saturday, with
best chances from ORH eastward to the Cape and Islands (lesser
chance/coverage west), and a couple could be strong. Thinking
decreased coverage after 21z Sunday. Winds become NW around
10-13 kt, with winds coming NE late in the day.
KBOS...High confidence in TAF but moderate on timing of wind
directions. VFR through 00z Sunday. Seabreeze has been delayed
but thinking it comes in around 20z Friday; by 00/01z Saturday,
winds could back to a NE component before turning SW around
14-15z Sat.
KBDL...High confidence in TAF. VFR, with WNW winds around 10 kt
becoming SW late today. TS possible after 22z Saturday.
Outlook /Saturday Night through Wednesday/...
Sunday: VFR. Breezy. Chance SHRA, isolated TSRA.
Sunday Night: Mainly VFR, with local MVFR possible. Breezy.
Slight chance SHRA.
Monday: VFR. Breezy.
Monday Night through Tuesday: VFR.
&&
.MARINE...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Today through Saturday...High confidence.
Today, winds remain similar to Thursdays setup, though generally
expected to remain just below Small Craft Advisory criteria across
Buzzards Bay, Vineyard Sound, and Nantucket Sound. Across the
remaining waters, winds up to 20 kt are possible through this
evening, then all waters should remain at or below 15 kt on Friday
and Friday night. Seas generally hold in the 2-4 ft range through
Friday night.
On Saturday, southwest winds increase with gusts approaching 25 kt
and seas building to 3-5 ft by early afternoon. It is becoming more
likely that Small Craft Advisory conditions will be needed Saturday
afternoon into the weekend as these conditions develop.
Outlook /Saturday Night through Wednesday/...
Saturday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft. Chance of rain showers.
Sunday: Winds less than 25 kt. Seas up to 5 ft. Chance of rain
showers.
Sunday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft. Slight chance of rain
showers.
Monday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Seas up to 5 ft.
Monday Night: Winds less than 25 kt. Seas up to 5 ft.
Tuesday: Winds less than 25 kt. Local rough seas.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 2 PM Saturday to 8 AM EDT Sunday for
ANZ232>235-237-254>256.
&&
$$
DISCUSSION...Dooley
AVIATION...Loconto/FT
MARINE...Dooley
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