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468
FXUS61 KBOX 080700
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
300 AM EDT Tue Oct 8 2024

.SYNOPSIS...
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Mainly dry and seasonable conditions through Wednesday, then a cold
front Wednesday night will be followed by cooler than normal
temperatures Thursday. Temperatures moderate Friday and especially
by Saturday when highs may reach into the 70s, before cooling off
again Sunday and Monday. Mainly dry weather lasts through Saturday,
though rain chances increase to close out the holiday weekend.
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&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Broad upper trough sets up across New Eng today as shortwave
energy sweeps across northern New Eng. Most pronounced cooling
aloft will be to the north where best chance of instability
showers. Further south across SNE, increasing moisture in the
850-700 mb layer ahead of the trough moves in from the west this
afternoon. Sunshine this morning will give way to sct-bkn
diurnal clouds this afternoon, especially interior, but dry
weather will prevail. Seasonable temps expected with highs mid-
upper 60s, cooler higher terrain, with a modest W-NW wind.
Overall a pleasant fall day.
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&&

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

Another shortwave rotating around the upper low to the north moves
across SNE overnight. Moisture is limited, but backing flow to SW
ahead of the shortwave will bring somewhat higher moisture to the
Cape/Islands where there is a low risk for a few showers overnight.
Otherwise, dry conditions with varying amounts of cloud cover. Lows
will be mostly in the 40s, with some upper 30s across western MA.

Wednesday...

Mean trough remains across New Eng with a more potent shortwave
rotating across the Gt Lakes into northern New Eng in the afternoon.
Cold pool aloft will be across northern NY and northern New Eng
where best chance of showers, although can`t rule out a few showers
spilling into NW MA during the afternoon. Otherwise, dry conditions
with sunshine mixed with diurnal cu. Slight cooling aloft so temps
should be a few degrees cooler than today, with highs low-mid 60s,
except upper 50s higher terrain, with a modest west wind.
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&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
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Key Points:

* Temperatures around normal this week coupled with cool nights

* Dry weather pattern likely prevails through much of the weekend
  with next chance to precipitation potentially arriving by late
  Sunday.

Details:

Wednesday Night and Thursday:

Wednesday night, the upper level trough and cold pool shifts further
eastward across the northeast. As the larger pattern shifts, a piece
of shortwave energy moves across accompanied by a surface cold
front. Ensemble guidance shows a good consensus for below normal
moisture across the region and with limited forcing overall, won`t
support precipitation. Increased cloud cover and cooler temperatures
are the more likely to accompany the front. Can`t rule out an
isolated shower or two overnight, but overall any precipitation will
be quite limited.

Southern New England still remain under the influence of the cold
pool Thursday with below normal 850mb temperatures. Slightly cooler
temperatures are possible Thursday given a reinforcing push of
cooler air with the front. Highs ranges in the mid 50s to near 60.
Surface high pressure will keep conditions dry Thursday with
decreased cloud cover.

Thursday night through weekend:

Thursday night will be a cool one and likely the coolest of the
week. Limited cloud cover will optimize radiational cooling in the
already cooler airmass. Lows should drop into the mid-upper 30s for
the higher elevation spots, upper 30s/low 40s across the interior,
and low to mid 40s for the urban centers. Even the NBM, which
typically runs a bit warm, is keen on the chillier night! As far as
frost/freeze goes, it remains a possibility in the higher elevation
spots

As the backside of the upper trough/cold pool pushes eastward, 850mb
temperature rebound back toward normal or even slightly above normal
by the weekend. This will promote daytime highs back into the 60s
Friday with potential for low 70s on Saturday.

Ensemble guidance shows potential for a weak wave to move through in
the late Sunday and Monday time frame which may bring the next
chance for rain to southern New England.
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&&

.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
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Forecast Confidence Levels:

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

Through 12z...

MVFR-IFR cigs Cape/Islands will scatter out and improve to VFR
06-08z. Otherwise VFR, except patchy valley fog through 08z. NW
wind 5-10 kt

Today through Wednesday...High Confidence.

VFR. SCT-BKN diurnal CU developing this afternoon and again Wed
afternoon, especially interior. Low risk for a few showers
Cape/Islands overnight tonight but VFR cigs. NW wind 10-15 kt
today, becoming light to calm tonight, then W 10-15 kt Wed.

KBOS TAF...High confidence in TAF.

KBDL TAF...High confidence in TAF.

Outlook /Wednesday Night through Saturday/...

VFR. Breezy.
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&&

.MARINE...
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Forecaster Confidence Levels:

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

Today through Wednesday...High Confidence.

Long period easterly swell will bring 4-6 ft seas to the outer
waters so SCA will continue today. Seas will subside this evening
over the southern waters but not until late tonight over the eastern
waters. Seas should be below 5 ft by Wed. W-NW winds will remain
below SCA thresholds.

Outlook /Wednesday Night through Saturday/...

Wednesday Night through Thursday: Winds less than 25 kt. Areas
of seas approaching 5 ft. Slight chance of rain showers.

Thursday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of seas approaching 5 ft.

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

Saturday: Winds less than 25 kt. Areas of seas approaching
5 ft.
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&&

.BOX WATCHES/WARNINGS/ADVISORIES...
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CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 8 AM EDT Wednesday for ANZ250-254-
     255.
     Small Craft Advisory until 8 PM EDT this evening for ANZ251-
     256.
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&&

$$

SYNOPSIS...KJC/Mensch
NEAR TERM...KJC
SHORT TERM...KJC
LONG TERM...Mensch
AVIATION...KJC/Mensch
MARINE...KJC/Mensch