631
FXUS61 KBOX 061913
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
313 PM EDT Sat Jul 6 2024

.SYNOPSIS...
Warm and very humid weather continues, with greater risk for
showers and thunderstorms across southeast New England tonight.
Mainly dry Sunday afternoon through Monday. Summertime heat and
humidity should prevail next week as well, along with scattered
showers and thunderstorms, especially Wednesday through
Saturday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Continuing to monitor thunderstorm potential this afternoon and
evening. Latest SPC mesoanalysis showed most-unstable CAPE
values in excess of 2,000 J/kg across much of southern New
England with effective shear values of 40-60 kts. Mid level
lapse rates have not improved, and will provide the brakes for
this scenario. Entrenched stratus towards southeastern New
England should also cause any thunderstorms to weaken as they
move east.

No epiphanies for timing and coverage of showers overnight after
reviewing the latest guidance suite. Still a low confidence
forecast overall. Have the greatest confidence in showers and
thunderstorms along and west of the CT River in MA and CT.

Very humid conditions continue, keeping low temperatures above
normal.

&&

.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
A front slowly sags into southern New England late tonight into
Sunday. Not much push behind this front, so thinking this front
is still lingering nearby into Sunday night, most likely toward
the coast.

Very humid conditions and above normal temperatures continue.
That said, a subtle intrusion of drier air in the mid levels
aloft should provide more of a cap on showers and thunderstorms
during this time.


&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Highlights:

 * Summertime heat and humidity most of next week - potential
   Heat Advisory for some Mon/Tue
 * Scattered showers/storms mainly Wed-Fri

Ensembles are in good agreement next week and feature persistent
subtropical ridge over the western Atlantic and upper trough
near Great Lakes. This pattern favors typical summertime heat
and humidity as SW flow aloft transports very warm and humid air
up the East Coast.

Core of heat and humidity looks to be Mon/Tue. We could reach
Heat Advisory criteria (heat index 95-99F for 2 or more hours
on consecutive days) away from coast and especially in the
Connecticut and Merrimack Valleys as well as interior eastern
MA. For rest of next week, presence of more cloud cover should
keep highs in 80s, but overnight lows will probably stay in 70s,
especially in urban areas.

As we`ve seen over the past week, there probably won`t be a lot
of larger scale forcing present to result in organized showers
or thunderstorms. Rather, we should see weaker short waves from
Great Lakes dampen out as they run into upper ridge offshore.
Timing of these short waves is always a problem in the model
world, especially at longer time ranges, but it does appear our
better chances of showers/storms will be in the Wed-Sat
timeframe (afternoon and evening) as we also have weak surface
fronts nearby.


&&

.AVIATION /18Z SATURDAY THROUGH WEDNESDAY/...
Forecast Confidence Levels:

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

Tonight: Moderate confidence overall, low on timing of SHRA/TS.

Sub-VFR likely thru midnight for most airports, as weak frontal
boundary sags SE toward the coastal waters. SHRA/TS likely to
be ongoing somewhere in the airspace, with trend being for a
gradual SE shift towards the south coast. Should see gradual
improvement in flight categories from NW to SE, but sub-VFR
likely to continue into early Sun morning for the south coast.
Winds continue SW around 5-10 kt, though will turn WSW late.

Sunday: High confidence.

Improvement to VFR expected for most, but can`t rule out
periodic SHRA and sub-VFR at ACK during the morning as frontal
boundary stalls. WSW winds 5-10 kt.

Sunday Night...High confidence.

Mainly VFR. Areas MVFR possible towards ACK, closer to a stalled
front.

KBOS TAF...Moderate confidence overall, low confidence on
SHRA/TS timing and coverage. Greater risk during and after the
evening push as boundary sags southward.

KBDL TAF...Moderate confidence overall, low confidence on
SHRA/TS timing.

Outlook /Monday through Wednesday/...

Monday through Monday Night: VFR.

Tuesday: VFR. Slight chance SHRA, isolated TSRA.

Tuesday Night: Mainly VFR, with local MVFR possible. Chance
SHRA, isolated TSRA.

Wednesday: VFR. Breezy. Chance SHRA, isolated TSRA.

&&

.MARINE...
Forecaster Confidence Levels:

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

Through Sunday Night:

S to SW flow continues as a front slowly approaches the waters
tonight, then likely stalls across the waters Sunday into Sunday
night. A few gusts up to 25 kt, along with marginal 5-foot seas
across the southern coastal waters, so continued the Small Craft
Advisories into Sunday. Areas of fog may reduce visibility below
1 mile late tonight. Visibility expected to improve Sunday.

Outlook /Monday through Wednesday/...

Monday through Tuesday: Winds less than 25 kt.

Tuesday Night: Winds less than 25 kt. Slight chance of rain
showers, isolated thunderstorms.

Wednesday: Winds less than 25 kt. Chance of rain showers,
isolated thunderstorms.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...High Risk for Rip Currents until 8 PM EDT this evening for
     MAZ020>024.
RI...High Risk for Rip Currents until 8 PM EDT this evening for
     RIZ006>008.
MARINE...Small Craft Advisory until 8 PM EDT this evening for
     ANZ232>235-237.
     Small Craft Advisory until 8 AM EDT Sunday for ANZ254.
     Small Craft Advisory until 11 AM EDT Sunday for ANZ255-256.

&&

$$

SYNOPSIS...Belk/JWD
NEAR TERM...Belk
SHORT TERM...Belk
LONG TERM...JWD
AVIATION...Belk/JWD
MARINE...Belk/JWD