-- Discussion containing changed information from previous version are highlighted. --
596
FXUS61 KBOX 031650
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
1250 PM EDT Mon Jun 3 2024

.SYNOPSIS...
High pressure will build into New England today. A back door
cold front will usher in cooler weather tonight and Tuesday,
mainly near the coast. Wet weather looks to return later
Wednesday night and Thursday as low pressure approaches from the
Ohio Valley. Scattered showers may last into the weekend as the
low meanders around southern New England.

&&

.NEAR TERM /UNTIL 7 PM THIS EVENING/...
945 AM Update: No significant changes.

Clearing is working its way south as high pressure builds into
region and mid level shortwave to our south heads offshore, so
trend of increasing sunshine from N to S is on track for
afternoon. Weak pressure gradient will allow coastal sea breezes
to develop later this morning, keeping temperatures cooler near
immediate coast (70s) with 80s inland.

&&

.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM TUESDAY/...
Highlights:

* Increasing low level moisture should bring in areas of low clouds
  and perhaps fog to SE MA.

* Spot shower or thunderstorm possible Tuesday afternoon mainly
  across north/central and western Massachusetts and northwest
  Connecticut.

Tonight: Low clouds advect in off the water, leading to a cloudy
night with areas of fog possible along the coast. A dry night, but
any areas of locally dense fog could lead to light drizzle, if this
were to happen, think it could occur on the Cape and/or Islands, but
confidence in that occurring is moderate to low, and have left any
mention of that out of the forecast grids... If confidence increases
today, don`t be surprised if subsequent forecast updates include it.
Temperatures tonight are seasonable int he middle to upper 50s.

Tuesday: Areas of morning fog and stratus lift with the high June
sun angle, leads to a mainly sunny day. Diurnal cu develop during
the afternoon with steep low level lapse rates, but mid-level lapse
rates remain less than ideal. Still, there remains chance of pop-up
showers and thunderstorms, they should remain widely scattered in
nature from the northern Worcester Hills to the Berkshires. Not
expecting anything severe. While not as warm as the previous days,
highs still top out in the middle and upper 70s, with the
Connecticut River Valley in the low 80s. A sea breeze sets up in
eastern Massachusetts and southern Rhode Island, leading to lower
than normal temperatures in the upper 60s and lower 70s. Dewpoints
are on the rise and climb into the upper 50s, while not overly
humid, after several days of rather low humidity - the humidity will
be noticeable.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Highlights:

* Generally dry Wed, warm temps, 80-85 away from the coast

* Widespread showers with embedded heavy downpours and isolated
  thunderstorms Wed night into Thu, along with turning more humid.
  Temps seasonable to slightly cooler than normal given clouds/rain.

* Not as wet Fri into the weekend, with less areal coverage of
  showers and embedded thunderstorm.

Precipitation...

Above normal heights and anticyclonic flow into New England persist
thru Wed. Hence, mainly dry weather prevails, although a low risk
for a few showers/thunderstorms across western MA/CT as cyclonic
flow approaches. However, by Wed night and especially into Thu,
below normal heights advects into the Great Lakes with cyclonic flow
into New England. This pattern change is accompanied by a slug of
PWATs about 180% of normal. This combination of anomalous moisture
coupled with cyclonic flow and an accompanying surface wave, should
yield widespread showers Wed night into Thu. Instability is lacking
so not expecting widespread convection, but isolated storms are
possible, which will enhance rainfall potential. Main hazard will be
heavy downpours given anomalous moisture coupled with modest jet
dynamics. Ensembles indicate low probabilities for 1+ inches Wed
night into Thu, but zero probabilities of 2+ inches. This seems
reasonable given how progressive pattern becomes. Mid/upper low and
associated cold pool lingers across the Great Lakes Fri,Sat and Sun.
This proximity to SNE will yield lots of diurnal clouds each day
along with the risk for scattered diurnal convection, but by no means
a washout, with many hours of dry weather.

Temperatures...

Return flow Wed yields low level WAA with 925 mb temps warming to
+18C to +20C. This will support a warm day with highs in the low to
mid 80s. Humidity remains in check with dew pts 55-60. Clouds and
widespread showers Thu hold temps in the 70s. Although, it will be
humid Thu with dew pts in the 60s. Despite cold pool aloft Friday,
drier weather than Thu helps boost highs to 75-80. Below normal
heights/cold pool aloft lingers across the Great Lakes into New
England next weekend. This will yield mild days with highs in the
70s and cool nights with lows in the 50s.

&&

.AVIATION /18Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
Forecast Confidence Levels:

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

18z TAFs: High confidence (60%).

VFR through this evening with coastal sea breezes and light
winds away from coast. Have more confidence in low clouds
affecting coastal terminals tonight, with IFR ceilings near
Cape Cod and Islands before midnight, and MVFR ceilings up
eastern MA coast into BOS closer to sunrise Tue. Also thinking
MVFR ceilings get into more of central and eastern MA including
KORH but confidence is a bit lower there than for coastal
locations. These lower ceilings slowly lift Tue morning with
VFR conditions returning by midday. E/NE winds prevail.

For the inland terminals, VFR through Tue night. Light winds
tonight become S/SE Tue.

KBOS TAF... High confidence (60%). MVFR ceilings most likely to
affect terminal 08z-11z but could linger a few hours longer.
More confident in VFR conditions Tue afternoon.

KBDL TAF... High confidence (80%).

Outlook /Wednesday through Friday/...

Wednesday: VFR.

Wednesday Night: Mainly VFR, with local IFR possible. Chance
SHRA.

Thursday: MVFR/IFR conditions possible. Breezy. SHRA likely,
isolated TSRA.

Thursday Night: Mainly VFR, with areas IFR possible. Chance
SHRA.

Friday: VFR. Chance SHRA, isolated TSRA.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
Forecaster Confidence Levels:

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

Today through Tuesday...

Surface high pressure continues to be the dominant weather
feature. A backdoor cold front will bring ENE winds to all the
waters today and tonight, wind shifts to the ESE across the
eastern waters on Tuesday while southern waters are more SSE.
Areas of low stratus and fog are possible overnight into early
Tuesday, leading to poor visibilities. Winds and seas continue
to remain below advisory criteria, wind speeds are 10 to 15
knots today, and 5 to 10 knots tonight into Tuesday. Waves
during this period are 1-2 ft.

Outlook /Tuesday Night through Friday/...

Tuesday: Winds less than 25 kt.

Tuesday Night: Winds less than 25 kt. Patchy fog. Local
visibility 1 to 3 nm.

Wednesday: Winds less than 25 kt.

Wednesday Night: Winds less than 25 kt. Chance of rain showers.

Thursday: Winds less than 25 kt. Areas of seas approaching
5 ft. Chance of rain showers, isolated thunderstorms.

Thursday Night through Friday: Winds less than 25 kt. Areas of
seas approaching 5 ft. Chance of rain showers.
-- End Changed Discussion --

&&

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

&&

$$

SYNOPSIS...Nocera/Dooley
NEAR TERM...JWD
SHORT TERM...Dooley
LONG TERM...Nocera
AVIATION...JWD
MARINE...Nocera/Dooley