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Area forecast discussion
National Weather Service Boston/Norton Massachusetts
439 am EDT Thu Jun 21 2018

Synopsis...

Low pressure near the New Jersey coast early this morning will
bring an area of showers across southern areas, which should
push offshore by midday. Another weak weather system may bring
some spotty showers across central and eastern areas this
afternoon. High pressure will bring dry conditions but a bit
cooler temperatures on Friday. Unsettled conditions Saturday,
continuing through early Monday with the chance of showers and
thunderstorms. Dry weather expected Tuesday and Wednesday.

&&

Near term /until 6 PM this evening/...

Area of showers moving steadily east across central CT/Rhode Island into S
coastal mass at 08z, as seen on latest kbox 88d radar loop. Low
level moisture increased quickly ahead of the rainfall, with
dewpts rising up to the lower-mid 60s, while holding in the 50s
further north where only some high clouds lingered overnight. Noting
a sharp northern cutoff of the precip with the differences in
the T/TD spreads. Precip moving east through around mid morning,
then will push offshore as another cold front approaches from
northern New England.

This next front will be mainly dry, but most models signaling a
rather potent mid level short wave associated with it. 00z model
suite all signaling the possibility of enough elevated
instability to cause some widely scattered showers to develop
mainly across central and eastern areas. The tq values were up
to 18-20, which could also mean elevated thunder. Did mention
isolated thunder as well.

If the precip does develop this afternoon, it should weaken
after 22z or so as the short wave moves through.

Expect temps to range from the upper 60s to mid 70s along the
immediate East Coast as winds shift to east-NE by around midday,
ranging to the lower 80s across the lower CT valley.

&&

Short term /6 PM this evening through 6 PM Friday/...

Tonight...
expect conditions to be mostly clear away from coastal areas
tonight. East-NE winds will continue with the high to the N, so
low level moisture will remain. Brought in low clouds and fog
especially along the coast, but could push further inland as
well. Should see lower conditions along the immediate coast.

Temps will fall back through the 50s, though may hold on close
to 60 in the urban centers.

Friday...
any coastal fog should dissipate by mid morning or so.
Otherwise, high pressure remains in control with mostly clear
conditions. It will remain cool especially along the coast with
continued onshore winds.

&&

Long term /Friday night through Wednesday/...
*/ highlights...

- Saturday perhaps not a washout, skirting rains S/east
- showers / t'storms north/west Sunday, sweeping southeast into Monday morning
- prolonged dry conditions during the week
- watching weeks-end for additional wet-weather disturbances

*/ overview...

Pattern this weekend should feature above normal precipitable
water. Precipitable water values drop off to near to below
normal levels early next week. Temperatures on the other hand
should remain near normal, except for Saturday, and perhaps
Monday.

Split mid level flow regime should merge into a more unified
flow across much of the towards Monday. It appears likely the
pattern will transition from a potent mid level low over
northern Quebec with a weaker cutoff over Indiana to start this
weekend, to one which features a more amplified mid level trough
by Monday. This trough should move over the North Atlantic
towards the middle of next week.

At the surface, this should mean a low pressure moving through
the Great Lakes towards northern New England this weekend. While
not a total washout, we will have at least a chance for showers
this weekend. A secondary cold front, along with a mid level
shortwave, should be enough to cause showers to linger into
Monday. This timing may change with later forecasts. Instability
is enough to warrant a mention of at least a few thunderstorms
at times this weekend.

High pressure with drier weather Tuesday into Wednesday.

&&

Aviation /09z Thursday through Monday/...
forecaster confidence levels...

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

Short term /through Friday/... high confidence.

Through 12z...VFR conditions across central and northern areas.
North CT/RI/se mass...mainly VFR, but patchy MVFR ceilings/visibilities move
into S coastal areas in -shra and patchy fog by around 12z.

Today...
VFR conditions central/north areas. Across NE CT/RI/se mass...
areas of MVFR-IFR ceilings/vsbys, lowest along the S coast, Cape Cod
and the islands. Conditions should improve from north-S through
midday. May see widely sct showers/isolated thunder across
central and eastern areas from midday through the afternoon.
Brief MVFR conditions possible. Light/variable winds early,
except S-SW 5-10 kt along the S coast, shift to east-NE by midday
or early afternoon.

Tonight...
mainly VFR. MVFR ceilings linger along southeast coastal areas with the
east-NE winds in place. Patchy fog with areas of MVFR visibilities move
onshore mainly across east mass into Rhode Island.

Friday...
mainly VFR, but with east winds lingering, may see lower clouds
linger across east coastal areas with local MVFR conditions
possible.

Kbos terminal...high confidence in taf. VFR through the evening
push, then some MVFR ceilings/visibilities may work in after 03z-04z Fri.

Kbdl terminal...high confidence in taf. Showers and lower
clouds/patchy fog pass S of the terminal. VFR conditions.

Outlook /Friday night through Monday/...moderate confidence.

Friday night: VFR. Breezy. Chance rain showers.

Saturday: mainly VFR, with local MVFR possible. Breezy. Chance
shra, isolated thunderstorms and rain.

Saturday night: MVFR/IFR conditions possible. Rain showers likely,
slight chance thunderstorms and rain.

Sunday: mainly VFR, with local IFR possible. Chance shra,
isolated thunderstorms and rain.

Sunday night: mainly VFR, with local MVFR possible. Chance
shra, isolated thunderstorms and rain.

Monday: VFR. Breezy. Chance rain showers.

&&

Marine...
forecaster confidence levels...

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

Short term /through Friday/...high confidence.

Today...low pressure will pass across the southern outer waters
with showers and patchy fog that will reduce visibility to 1-3
nm at times through midday or early this afternoon. Seas 3 ft
or less. Light west winds will shift to east-NE with gusts briefly up
to 20 kt.

Tonight and Friday...high pressure will build north of the waters,
keeping a east-NE wind flow in place through most of this
timeframe. May see occasional gusts to 20 kt at times. Seas up
to 3 ft, though may approach 4 ft at times across the southern
waters Fri. Areas of fog will reduce visibility tonight into
Friday morning.

Outlook /Friday night through Monday/...moderate confidence.

Friday night: winds less than 25 kt. Areas of seas approaching
5 ft. Chance of rain showers.

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

Saturday night: winds less than 25 kt. Areas of seas
approaching 5 ft. Rain showers likely, and a slight chance of
thunderstorms.

Sunday through Sunday night: winds less than 25 kt. Local rough
seas. Slight chance of rain showers, with isolated
thunderstorms.

Monday: winds less than 25 kt. Seas up to 5 ft. Chance of rain
showers.

&&

Box watches/warnings/advisories...
CT...none.
Massachusetts...none.
Rhode Island...none.
Marine...none.

&&

$$
Synopsis...Belk/evt

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