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212
FXUS61 KBOX 041358
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
958 AM EDT Fri Oct 4 2024

.SYNOPSIS...
Warm and dry to round out the work week. Scattered showers move
through the region very late tonight into early Saturday
morning but expecting another mild and dry afternoon. A cold
front moves through southern New England late Sunday night into
Monday, bringing a period of rain showers. This cold front will
result in a cooler, fall-like weather pattern Tuesday through
much of next week with mainly dry weather.

&&

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

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10 AM Update...

On satellite imagery, breaks in the high level clouds have
revealed the low stratus and fog across the CT River Valley,
central MA, and other locally low lying areas. In some areas,
such as Worcester, fog/low clouds have eroded. Further westward
toward the CT River Valley, the fog/stratus will be slower to
improve. Breaks in the high level clouds and increased heating
after sunrise will help scatter this out in the next few hours.
Made a few minor adjustments to cloud cover and temperatures,
but otherwise it will be a warm Fall day across southern New
England with a mix of sun and clouds.


645 AM Update...

* Mix of clouds & sun today with highs mainly in the lower to
  middle 70s, but a few upper 70s possible in the CT Valley

Patchy dense fog early this morning in our typical low-lying
locations especially in the Lower CT River Valley...should burn
off by mid to late morning. Mid and high clouds will increase
again this afternoon and evening ahead of the incoming
shortwave, so expecting another day with a mix of clouds and
sun. Will note that guidance is not resolving potential cloud
cover with much certainty, with solutions for today ranging from
mostly sunny to mostly cloudy; which may impact diurnal heating
by a few degrees.

High pressure begins to shift offshore today as weak shortwave
approaches from the west. Mid level ridging remains robust, with
850mb temperatures climbing towards 12C this morning, which
will support high temperatures in the low to mid 70s with
perhaps a few upper 70s across parts of the CT River Valley.
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&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
Tonight and Saturday...

Considerable cloudiness and elevated dewpoints, in the mid to upper
50s for most, will dampen radiational cooling tonight. Shortwave
axis/weak front swings through southern New England during the early
hours of Saturday morning which will generate scattered showers
between ~06-16Z. Precipitation potential is not looking promising
with both global ensembles and high resolution guidance suggesting
generally less than 0.1" of QPF can be expected by lunch time
Saturday. GFS ensemble probabilities have just a 20% chance of
exceeding 0.1" of QPF north of the Route 2 Corridor, with lesser
amounts elsewhere. The 00Z HRRR portrays a shut out, with no
rain expected across southern New England. Do think the GFS and
other hi- res models like the FV3 and NAM are a bit closer to
reality than the HRRR with their depiction of scattered showers.

Saturday certainly wont be a washout if you can dodge the morning
showers, as a drying trend develops into the evening. In fact,
Saturday is looking to be another mild day, with temperatures in the
70s, which combined with clearing skies will make for a great fall
evening for outdoor activities!

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Key Points...

* Dry with seasonable temps Sat night & Sun
* Period of Showers late Sun night into Mon
* Mainly dry but cool/fall-like weather Tue/Wed/Thu with some frost

Details...

Saturday night and Sunday...

Brief ridge of high pressure builds over the region Sat night into
Sun. This will provide dry & seasonable weather with lots of
sunshine to close out the weekend. Good radiational cooling
conditions should allow overnight lows to drop mainly in the 40s
with some lower 50s in the Urban Heat Island of Boston as well as
the outer-Cape/Nantucket. High temps on Sun will be mainly in the
upper 60s to near 70 although a few degrees cooler along the
immediate coast and high terrain.

Sunday night and Monday...

A shortwave/cold front will approach the region late Sun night into
Mon. A period of warm advection and ample forcing should result in a
round of showers late Sun night into Mon. Not looking at heavy
rainfall amounts...but do expect measurable rain to occur given the
period of modest forcing and moisture advection. Clouds and showers
Mon will probably hold high temps mainly in the 60s.

Tuesday through Thursday...

Amplifying closed upper level low across Quebec will allow a
deep northeast trough to develop. The result will be persistent
northwest flow aloft and at the surface...yielding our first
taste of cool/fall-like weather. High temps will be held mainly
in the upper 50s to the middle 60s and may even be a bit cooler
by Thu with a reinforcing shot of cool air. Overnight low temps
should bottom out mainly in the 30s to the lower 40s Tue night
and Wed night...which probably will result in some frost late
Tue night and again late Wed night. Even the Urban Heat Islands
of Boston and Providence should see lows bottom out in the
middle to upper 40s.

Mainly dry weather will prevail Tue/Wed/Thu...but some upper level
shortwave energy may result in a brief spot shower from time to
time. But overall...dry but cool fall-like weather is on tap for the
region.

&&

.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
Forecast Confidence Levels:

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

12z TAF Update:

Today...High Confidence

Patchy radiation fog yielding LIFR to IFR with the focus across
the CT River Valley will give way to VFR by mid to late morning.
VFR elsewhere expect all terminals to be VFR by the lunch hour.
SSW winds today less than 10kt, with some east coast seabreezes
possible by afternoon.

Tonight...Moderate confidence

Approaching cold front will result in a broken deck of VFR to
marginal MVFR ceilings with a few brief showers developing
between 06-12Z. Light winds shift to the NW behind the frontal
passage.

Saturday...Moderate Confidence

A few brief showers possible into mid morning. Otherwise any
lower conditions improve by late morning. Winds generally become N,
around 10kt with gusts to 15 possible.

BOS TAF...High confidence in TAF.

VFR. Sea breeze develops likely in the 15-17z time frame with
SE/ESE winds. A few brief showers may be in the vicinity of the
terminal towards 12z.

BDL TAF...High confidence in TAF.

VFR, although localized patches of ground fog may come in and
out of the terminal through 13Z this morning. A few brief Light
rain showers possible by 06Z Saturday. Light SW/SSW winds
today.

Outlook /Saturday Night through Tuesday/...

Saturday Night: VFR. Breezy.

Sunday: VFR.

Sunday Night: Mainly VFR, with areas MVFR possible. Chance
SHRA.

Monday: Mainly VFR, with areas MVFR possible. Breezy. SHRA.

Monday Night: VFR.

Tuesday: VFR. Breezy.

&&

.MARINE...
Forecaster Confidence Levels:

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

Today and Tonight...High Confidence.

Waves 2-4ft. Marine stratus and fog across the southern waters
gradually dissipates this morning. S/SE winds through early
Saturday morning less than 15 kts.

Saturday...High Confidence

Scattered showers possible early Saturday morning into Saturday
mid-day, though showers may linger across the eastern outer
waters into Saturday evening. Winds shift behind passing front
to the NW; winds less than 25 kts. Waves 2-4 ft.

Outlook /Saturday Night through Tuesday/...

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

Sunday: Winds less than 25 kt. Seas up to 5 ft.

Sunday Night: Winds less than 25 kt. Seas up to 5 ft. Chance of
rain showers.

Monday: Winds less than 25 kt. Areas of rough seas. Rain
showers.

Monday Night: Winds less than 25 kt. Areas of rough seas.
Slight chance of rain showers.

Tuesday: Winds less than 25 kt. Seas up to 5 ft.

&&

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

&&

$$

SYNOPSIS...Frank/KS
NEAR TERM...Frank/Mensch/KS
SHORT TERM...KS
LONG TERM...Frank
AVIATION...Frank/KS
MARINE...Frank/KS