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Area forecast discussion
National Weather Service Boston/Norton Massachusetts
931 am EDT Wed Oct 23 2019

Synopsis...

A cold front will move off the coast this morning followed by
dry and mild conditions. Dry and seasonable conditions continue
Thursday and Friday with a gusty southwest wind Thursday. A cold
front sweeps through with a few showers Friday night. High
pressure brings dry seasonably cool temperatures Saturday.
Another cold front brings rain Sunday and Sunday night. High
pressure returns with dry weather Monday.

&&

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

930 am update...

The cold front has already pushed to the Cape Cod canal at mid
morning and it will be exiting the cape/islands in the next 1 to 2
hours. The showers have already exited the region for the most part.

Sunshine is emerging across western Massachusetts & CT. This trend
will continue and expect plenty of sunshine in most locations by
lunch time. Given the mild start and plenty of sunshine
expected by afternoon, highs should reach the middle to upper
60s in many locations. It is not out of the question that a few
locations touch 70. It will become a bit breezy as better mixing
develops by afternoon, but overall a very nice late October afternoon
is in store for the region.

&&

Short term /6 PM this evening through 6 PM Thursday/...
high pressure approaches our region from the south. Dry weather
with mainly clear skies expected. Near normal temperatures
should continue.

&&

Long term /Thursday night through Tuesday/...
highlights...

* light showers possible late Friday into Saturday
* dry much of Saturday then rain returns Sunday
* seasonable temperatures continue with a mostly dry early next
week

Thursday night through Saturday...

The first of several shortwave disturbances expected during the
extended forecast will bring rain chances to the region Friday
night. However, on the whole most of the period should be dry. A
weak cold front will try to drop through southern New England
Thursday night, but lack of moisture and dynamics should
preclude US getting any showers out of it; perhaps some
increased cloud cover. The more significant shortwave moves
through overnight Friday into Saturday. Ahead of that shortwave
SW flow brings up increasing, if marginal, moisture (pwats
>.75"). This plume of moisture with a decent 500 mb vortmax and
favorable 300 mb jet dynamics will bring rain showers beginning as
early as Friday evening. It shouldn't be a very impactful rain
event as models have trended drier, and most should fall between
sunset Friday and sunrise on Saturday.

By Saturday morning high pressure is again taking control and
skies clear through the morning into early afternoon. Overall a
fairly nice day is expected with slightly cooler than normal
temperatures for late October, in the mid to upper 50s.

Sunday...

Our next shot of more significant rain comes Sunday. Still some
timing uncertainty (the GFS continues to be the more
progressive outlier, bringing in rain as early as Saturday
evening, while the more consistent ec keeps things slower), but
guidance is coming into agreement on a deeper shortwave and
surface low crossing the region on or about Sunday. Ahead of the
cold front lots of moisture transport into southern New England in the warm
sector, with pwats up to 1.5" and sfc dewpoints approaching 60f
along the South Coast. As the low strengthens over the region a
strong low level jet with all the available moisture may give US a soaking
rain event. At this point quantitative precipitation forecast anywhere from 1 to 1.5 inches
seems plausible. Again, confidence is lower given we're still 5
days out, but eyes should be on Sunday for our next wet weather
maker. Temperatures will depend a good deal on frontal timing
and how far north the warm sector progresses, so non- diurnal
highs are possible.

Monday and Tuesday...

Considerably lower confidence on the first half of next week
contingent on how sunday's system plays out. However, leaning
toward a mostly dry Monday-Tuesday under building high pressure
given the more consistent ec solution.

&&

Aviation /14z Wednesday through Sunday/...
forecaster confidence levels...

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

Short term /through Thursday/...

1330z update...

Today...high confidence. Leftover MVFR/IFR improving to VFR
from west to east through 15 or 16z. West-northwest wind gusts of 20 to 25 knots
develop by afternoon.

Tonight and Thursday...high confidence. VFR.

Kbos terminal...high confidence in taf.

Kbdl terminal...high confidence in taf.

Outlook /Thursday night through Sunday/...moderate confidence to

Thursday night: VFR. Breezy.

Friday: VFR.

Friday night: VFR. Slight chance rain showers.

Saturday: VFR.

Saturday night: VFR. Breezy. Chance rain showers.

Sunday: mainly VFR, with local IFR possible. Breezy. Rain showers
likely.

&&

Marine...
forecaster confidence levels...

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

Short term /through Thursday/...high confidence.

A cold front will cross the waters this morning from the west.
Gusty west winds will follow this front this afternoon and
evening. Winds and seas diminish tonight into Thursday as a high
pressure approaches from the south.

Outlook /Thursday night through Sunday/...moderate confidence to

Thursday night: winds less than 25 kt. Seas locally approaching
5 ft.

Friday: winds less than 25 kt.

Friday night: winds less than 25 kt. Slight chance of rain
showers.

Saturday: winds less than 25 kt.

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

Sunday: moderate risk for Small Craft Advisory winds with gusts
up to 25 kt. Areas of rough seas. Rain showers likely.

&&

Box watches/warnings/advisories...
CT...none.
Massachusetts...none.
Rhode Island...none.
Marine...Small Craft Advisory until 6 PM EDT this evening for anz235-
237.
Small Craft Advisory until noon EDT Thursday for anz250-254.
Small Craft Advisory until 2 am EDT Thursday for anz251-256.
Small Craft Advisory until 6 am EDT Thursday for anz255.

&&

$$
Synopsis...Belk/bw

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