506
FXUS61 KBOX 191929
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
329 PM EDT Sat Oct 19 2024

.SYNOPSIS...
Strong high pressure settles over the Northeast states this weekend
into midweek, bringing dry conditions and warmer than normal temperatures.
A change in airmass occurs Thursday, with the passage of a front,
which may bring our next chance for showers.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...

330 PM Update:

Tonight...

Spectacular fall weather continues into this evening, with temps in
the upper 60s and low 70s at 3 PM, slowly fall back into the low and
mid 60s toward sunset (Boston at 5:55 PM and Hartford 6:02 PM). Then
another cool overnight, as a dry airmass with dew pts in the 30s
(40s along the coast), combines with 1030+ mb high, clear conditions
and light winds to support another round of radiational cooling,
with temps tumbling after sunset. Given this setup, derived lows
tonight from the cooler MOS guidance, which supports mins in the 30s
in the typically cooler locations of interior eastern MA, the CT
River Valley and into parts of eastern CT. This is where some patchy
frost is possibly. Otherwise, the remainder of the area will
experience mins in the 40s, except 45-50 in the urban areas.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...

330 PM Update:

Sunday...

Weak northern stream short wave trough moves across the region and
this somewhat erodes the northern periphery of the high amplitude
ridge over the Northeast. However, dry WNW flow prevails aloft,
providing another mostly sunny day (just some mid/high clouds from
time to time). Airmass continues to warm slightly with 925 mb temps
up to +14C, about a 1 degree warmer than Saturday. This combined
with more of a WSW wind Sunday, will yield warmer highs of 70-75,
about 10 degs warmer than normal. Cooler along the south coast with
highs in the 60s. This is in response to WSW winds 10-15 mph
streaming across SST in the upper 50s and lower 60s. Overall,
another gem of a day by late October standards.

Sunday night...

Quiet weather continues with deep layer dry WNW flow. Airmass not
quite as dry or cool as previous days, therefore mins come up a bit
with lows mainly in the 40s, to around 50 in the urban areas.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...

330 PM update...

Key Points

* Dry with above normal temps through Wednesday

* Cold front brings light rain and cooler temps Thursday and Friday

The upper-level ridge remains anchored over the region to start the
work week with dry and tranquil conditions expected through
Wednesday. Temperatures through Wednesday remain above normal with
850mb temps around +10C to +12C.  The warmest day this week looks to
be Monday, with sunny skies and downsloping westerly winds.  High
temps across the region will likely make the middle to upper 70s,
with low 80s a possibility in the lower CT river valley and SE MA,
away from the coasts.  Tuesday and Wednesday will still be mild, but
onshore flow should hold highs in the low to mid-70s.

The pattern changes quickly Wednesday night into Thursday as a fast-
moving shortwave trough and cold front traverses the region.  There
is still quite a bit of uncertainty on the timing of this system,
with the GFS and EURO moving the front through Thursday morning
while the Canadian waits to bring it through until Thursday evening.
Ensemble guidance is in good agreement with QPF chances, with most
ensemble systems showing a 10 to 20% chance for a tenth inch of
rain. Temperatures behind the front take a dive off the deep end,
with highs Thursday dropping to the low to mid-60s, then mid to
upper 50s for Friday.

&&

.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
Forecast Confidence Levels:

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

18z TAF Update:

Tonight: High confidence.

VFR. Light S-SW winds to trend light W overnight. Dry weather
prevails.

Sunday: High confidence.

VFR. WSW winds 10-15 kt likely precludes seabreeze development. Dry
weather continues.

Sunday night: High confidence.

VFR with light WSW winds along with dry weather.

KBOS TAF...High confidence. ESE winds slowly make the turn to south
and then SW this evening and overnight. WSW winds 10-15 kt should
preclude seabreeze development. Dry weather UFN.

KBDL TAF...High confidence in TAF. VFR. Light S-SE winds becoming SW
overnight, then WSW Sunday.

Outlook /Sunday through Wednesday/

Monday through Wednesday Night: VFR.

Thursday: VFR. Slight chance SHRA.

&&

.MARINE...
Forecaster Confidence Levels:

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

330 PM Update:

Overall high confidence.

Very tranquil boating conditions for mid to late Oct. Light S-SE
winds this evening, become S-SW tonight, then WSW Sunday and Sunday
night, at light speeds. Good vsby and dry weather prevail.

Outlook /Monday through Thursday/...

Monday through Wednesday: Winds less than 25 kt.

Wednesday Night: Winds less than 25 kt. Seas locally
approaching 5 ft. Slight chance of rain showers.

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

&&

.FIRE WEATHER...
330 PM Update:

Persistent dry weather, low min RH late morning into the afternoon
and dry fuels will combine to yield elevated fire weather
parameters. Despite light winds, collaboration with fire weather
partners supports the idea of continuing our special weather
statement to increase public awareness, given high recreation this
weekend.

&&

.CLIMATE...

330 PM update...

Here are the record highs for Monday, October 21st.

BOS 82/1920
PVD 81/1920
BDL 82/1920
ORH 80/1920

&&

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

&&

$$

SYNOPSIS...KP/Nocera
NEAR TERM...Nocera
SHORT TERM...Nocera
LONG TERM...KP
AVIATION...KP/Nocera
MARINE...KP/Nocera
FIRE WEATHER...Nocera
CLIMATE...Nocera