BOX issues Area Forecast Discussion (AFD) at Jul 8, 3:00 PM EDT
053
FXUS61 KBOX 081900
AFDBOX
Area Forecast Discussion
National Weather Service Boston/Norton MA
300 PM EDT Wed Jul 8 2026
.WHAT HAS CHANGED...
A Rip Current Statement is in effect through this evening for
eastern and ocean facing beaches in Massachusetts. A Small Craft
Advisory remains in effect until 8 pm this evening.
&&
.KEY MESSAGES...
- Becoming warmer with increasing humidity through the end of
the work week.
- Warm, humid weather returns late in the week. Scattered
showers and thunderstorms possible both days but better
chances looking to be on Friday.
- Drier, seasonably cool and less humid weather for the weekend
into early next week
&&
.DISCUSSION...
KEY MESSAGE 1...Becoming warmer with increasing humidity
through the end of the work week.
High pressure and mostly clear skies continue through most of
Thursday. 925mb temperatures rising to near 20C and plenty of
sunshine will allow for surface temperatures to begin to creep
up above seasonable norms... likely near 90 across most of
southern New England by Thursday. Humidity will begin to
increase under broad WSW flow, with dewpoints increasing to near
or just above 70 (at times) Thursday. A cold front moving
through Thursday evening could bring chances for isolated to
scattered showers and thunderstorms later in the
night/overnight, but the highest risk currently remains in
western MA.
A Rip Current Statement has also been issued through this
evening for eastern MA, primarily for ocean facing beaches, due
to prolonged northeasterly flow and 5+ ft seas.
KEY MESSAGE 2...Scattered thunderstorms along a cold front
Friday afternoon to early evening. Although severe weather
potential looks minimal at this time, lightning and torrential
downpours are the main risks.
Warm and humid weather continues into Friday to go along with
partly to mostly cloudy skies. A cold front will be gradually
sagging southward from northern New England during the early
afternoon in northern MA and reaching the southern CT-RI-MA
coastline by early evening. This will pose a better chance for
scattered showers and thunderstorms to develop than compared to
Thursday.
The biggest uncertainties specific to the thunderstorm forecast
are the degree of instability we can muster and how quickly
will the front progress offshore. Both the 12z NAM and 12z GFS
capture the instability envelope well, with the NAM's CAPE
values around 1500- 2500 J/kg due to its high-dewpoint bias,
while the GFS's overmixing bias shows considerably lower values
at around 500 J/kg or less. The answer is probably somewhere in
the middle; shear values are also on the lower side at around 30
kt, which should mitigate or limit any organized severe weather
potential outside of water-loaded downdrafts. The main risks
looks to be lightning and slow-moving heavy downpours, which
could lead to instances of street flooding in areas that see
repeated thunderstorms. Latest guidance indicates 700- 500 mb
heights which become increasingly parallel to the southward-
sagging frontal boundary, which adds to the risk for slower-
moving storms and also casts some uncertainty when we clear out,
with the Canadian guidance suggesting post-frontal light rains
lingering into part of Saturday along the South Coast.
KEY MESSAGE 3...Drier, seasonably cool and less humid weather
for the weekend into early next week.
Even if the cold front from Friday night takes a little bit
longer to fully clear out from the South Coast, we should be
trending drier by Saturday late morning. The 500 mb pattern then
transitions to one of cyclonic flow/troughing in the mean,
which favors cooler temperatures (low to mid 80s) and lower
humidity levels than experienced for late in the week. Weekend
appears favorable for outdoor plans with nice summer weather.
We'll be on the far western periphery of a pretty impressive
upper level ridge which latest guidance still shows reaching to
nearly 600 dm building over the northern/central Plains and
upper Midwest. We still might need to keep an eye on possible
storminess pivoting around the ridge but it looks as though the
weekend into early next week ends up drier than not.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
18Z TAF Update:
Wednesday...High confidence.
VFR. Light and variable winds away from the south coastal
terminals, except a seabreeze at BOS until 00-02z. FEW-SCT cloud
deck around 4kft
Wednesday night...High confidence.
VFR. SW winds 5-10 kts.
Thursday...High confidence.
VFR. SW winds 8-12 kts with gusts 20-25 kts. Isolated shower or
thunderstorm possible after 20Z.
KBOS Terminal...High confidence.
KBDL Terminal...High confidence in TAF.
Outlook /Friday through Monday/...
Friday: VFR. Chance SHRA, chance TSRA.
Friday Night through Sunday Night: VFR.
Monday: VFR. Breezy.
&&
.MARINE...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Through Friday Morning...High confidence.
SCA conditions continue in the the coastal waters through this
evening with NE wind gusts around 25 kts. Conditions improve
overnight into Thursday as high pressure builds over the region.
A weak front approaches the region later Thursday with showers
and thunderstorms possible over the southern waters.
Outlook /Friday through Monday/...
Friday: Winds less than 25 kt. Slight chance of rain showers.
Friday Night: Winds less than 25 kt. Seas locally approaching
5 ft. Slight chance of rain showers.
Saturday through Saturday Night: Winds less than 25 kt. Areas
of seas approaching 5 ft.
Sunday: Winds less than 25 kt. Seas locally approaching 5 ft.
Sunday Night through Monday: Winds less than 25 kt.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...High Risk for Rip Currents until 11 PM EDT this evening for MAZ007-
014>016-019-022-024.
RI...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ250-
254-255.
&&
$$
DISCUSSION...Loconto/McMinn
AVIATION...Loconto/McMinn
MARINE...Loconto/McMinn
Source: BOX issues Area Forecast Discussion (AFD) at Jul 8, 3:00 PM EDT (https://mesonet.agron.iastate.edu/p.php?pid=202607081900-KBOX-FXUS61-AFDBOX)
----------------
If I'm using your data in a way that is against your terms please email the team at "threatweb@pupswoof117.com"! I am a bot who will not respond in the comments at all and is only designed to post RSS feeds!