-- Discussion containing changed information from previous version are highlighted. --
658
FXUS61 KBOX 151726
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
126 PM EDT Sat Jun 15 2024

.SYNOPSIS...
High pressure will bring dry and pleasant Father`s Day weekend. Dangerous
heat and humidity begin to arrive on Tuesday and peak in the
Wednesday through Friday time frame. Near record high
temperatures are possible with afternoon Heat Indices between 95
and 105 degrees.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

-- Changed Discussion --
A weak shortwave passing overhead is providing just enough lift
to increase cloudcover over eastern MA this morning. We should
continue to see these dissipate over the next several hours as
mid level ridging moves in.

Previous Discussion...

* Plenty of sunshine today with highs well up into the upper 70s
  to the lower 80s along with lowering humidity

Leftover clouds now confined to eastern MA and expect those to
dissipate through the morning as a very dry airmass fills in
behind. Winds turn northerly today with highs mainly in the
upper 70s to low 80s along with plenty of sunshine. Humidity
will also be noticeably lower with dewpoints dropping into the
40s and 50s. Northerly winds and cold air advection will promote
mixing which will allow for gusts of 15 to 20 mph today until
sunset.
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
Tonight

Upper level ridge axis and surface high pressure move in overhead.
With clear skies, decreasing winds, and dewpoints in the 40s, strong
radiational cooling will take place. Overnight lows will drop into
the upper 40s to low 50s region wide. NW MA will likely be the
coldest with lows in the low 40s.

Tomorrow

High pressure and dry airmass remain over the region. A passing weak
500mb shortwave will bring some high clouds and filtered sunshine to
the region. All in all, Sunday will be another gorgeous day with
highs in the upper 70s to low 80s, and dewpoints still in the upper
40s to low 50s. Winds will also be also be light as they turn from
northerly to southerly late in the day.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Key Points...

* Dangerous Heat & Humidity Tue through Fri
* Near Record highs with Heat Indices 95-105 degrees
* Mainly dry weather next week outside widely scattered t-storm risk

Details...

The main story continues to be the expected dangerous heat and
humidity in store for much of the region next week. Ensembles
continue to be in excellent agreement in an anomalous upper level
ridge building across New England. Guidance shows 500 mb height
fields approaching 600 dm in our region...which is rarely seen in
our part of the country and a strong signal for the potential of
record heat. This is also supported by the NAEFS & EPS Situational
Awareness tables...which indicates several parameters outside the
models climatology. That is a strong indication for the potential of
a rare/highly unusual weather event...in this case being heat and
humidity.

The dangerous heat and humidity arrive Tue across the interior, but
appears localized sea breezes/onshore flow may limit the initial
risk on the immediate coast. The heat & humidity should peak in the
Wed through Fri time frame with the only possible relief along the
immediate coast during times of localized sea breezes. Otherwise,
ensemble guidance data supports near record highs well into the
90s...perhaps touching 100 degrees in spots. If that were to
occur...we would challenge all time record highs for the month of
June in spots. Either way though the main story will be several days
of dangerous heat & humidity. Afternoon Heat Indices will reach into
the 95 to 105 degree range. There will not be much relief at night
with heat indices remaining in the 70s.

Upper level ridging will keep the vast majority of the upcoming work
week dry. That being said...near record high temperatures with
modest instability will result in a widely scattered t-storm threat.
This risk may increase towards the end of the work week as a cold
front approaches the region.

So in a nutshell...dangerous heat and humidity is the
concern for much of next week perhaps even challenging all time June
high temperature records in spots!

&&

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

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

18z TAF Update...

This afternoon...High Confidence.

VFR. N winds 10 to 15 knots with a few gusts to 20 knots early this
afternoon.

Tonight...High Confidence.

VFR. Light N winds.

Sunday...

VFR. Light winds turn southerly with localized sea breezes.

Sunday night...

VFR. Light S winds.

KBOS TAF...High confidence in TAF.

KBDL TAF...High confidence in TAF.

Outlook /Sunday Night through Wednesday/...

Sunday Night: VFR.

Monday through Tuesday: VFR. Breezy.

Tuesday Night: VFR.

Juneteenth: Mainly VFR, with local MVFR possible. Breezy.
Slight chance SHRA, slight chance TSRA.
-- End Changed Discussion --

&&

.MARINE...
Forecaster Confidence Levels:

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

Today:

Winds turn north and gust 15 to 20mph. Seas 2-4 feet.

Tonight:

Clear conditions and generally light winds. Seas around 2-4
feet.

Tomorrow:

Clear conditions and light winds. Seas around 2-4 feet.

Outlook /Sunday Night through Wednesday/...

Sunday Night through Monday: Winds less than 25 kt.

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

Tuesday through Juneteenth: Winds less than 25 kt.

&&

.CLIMATE...
Daily Record High Temperatures...

Tuesday, June 18th

BOS - 94F (1929)
BDL - 95F (1994)
PVD - 94F (1929)
ORH - 93F (1929)

Wednesday, June 19th

BOS - 96F (1923)
BDL - 95F (1995)
PVD - 94F (1923)
ORH - 93F (1923)

Thursday, June 20th

BOS - 98F (1953)
BDL - 97F (2012)
PVD - 95F (1941)
ORH - 93F (1953)

Last Day of 100F (or greater)

BOS - 100F (07/24/2022)
BDL - 100F (07/21/2019)
PVD - 100F (07/28/2020)
ORH - 102F (07/04/1911)

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...None.

&&

$$

SYNOPSIS...Frank/KP
NEAR TERM...Frank/BW/KP
SHORT TERM...KP
LONG TERM...Frank
AVIATION...Frank/BW/KP
MARINE...Frank/KP
CLIMATE...Dooley