Area Forecast Discussion Issued by NWS Boston, MA
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000
FXUS61 KBOX 170142
AFDBOX
Area Forecast Discussion
National Weather Service Boston/Norton MA
942 PM EDT Sat Mar 16 2024
.SYNOPSIS...
A cold front will bring a brief round of showers early tomorrow
morning along with gusty winds into tomorrow afternoon. Mainly dry
Sunday afternoon and evening with mild temperatures.
Temperatures trending near to cooler than seasonable for much of
the upcoming week. Isolated showers possible Monday through
Thursday along with gusty winds. Drier on Friday.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
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940 PM Update...
* Overnight low temps in the upper 30s to the lower 40s
* Scattered showers develop toward daybreak
An approaching shortwave/cold front was in the beginning stages
of inducing a modest SSW low level jet overnight. In
response...low level moisture was increasing a bit allowing for
low clouds to overspread the Cape and Islands. We should see an
increase in mid/high level cloudiness overnight across the rest
of the region. Lows should bottom out in the upper 30s to the
lower 40s...but readings may rise a bit near daybreak with
thickening clouds. We also expect scattered showers to develop
toward daybreak as the forcing for ascent increases ahead of the
shortwave trough. The modest low level jet will result in some
SW 20-30 mph wind gusts developing near daybreak towards the
southeast New England coast.-- End Changed Discussion --
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Tomorrow
A cold frontal passage will bring a period of light rain showers
early tomorrow morning. Showers should enter from the NW after 5am
and move offshore to the east by noon. With weak forcing aloft,
quick moving front, and PWATS only around 0.5-0.6 inches, QPF
amounts will remain very light around 1/10th of an inch with
isolated areas of a quarter inch. Behind the front, skies begin to
quickly clear. This should help high temperatures jump into the
upper 50s to low 60s before surface winds turn NW and start
advecting in colder air. Winds remain gusty at 20-30mph out of
the SW initially, but turning WNW in the afternoon.
Tomorrow night
Upper level trough and cold pool begin to work in. Winds decrease a
bit overnight as the boundary layer tries to decouple, however, cold
air advection will promote mixing overnight and winds could remain
gusty at 10-20mph. Even with gusty winds, overnight lows will drop
near or below freezing away from the immediate coastlines with clear
skies and cold air advection.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
Key Points...
* Temperatures seasonable this week with highs in the 40s.
* Spotty showers possible Mon/Tue and more widespread on Wednesday,
lingering into Thursday; not a washout.
* Dry on Friday before another system next weekend.
The bulk of this week will be influenced mainly by a broad mid/upper
level trough which lingers over the northcentral/northeast U.S.
Several disturbances will round the base of the trough through the
week providing enhanced lift and rain chances along with it before
more zonal flow returns briefly to end the week. Temperatures
will dip down to normal or just below thanks to this trough,
with highs staying in the 40s. Given our close proximity to a
series of lows just to our north and east much of the week,
winds will remain gusty each day.
This week won`t be a washout, with only slight chances of rain or
graupel showers Monday and Tuesday thanks mostly to the cold pool
aloft with 500 mb temps in the -20 to -30C range. This, combined
with surface temps in the 40s to near 50 will lead to diurnal clouds
and spotty showers. We`re also getting into that season where steep
lapse rates like these (6-8c/km) may lead to graupel showers. Best
chance between Monday and Tuesday looks to be on Tuesday.
By Wednesday we`ll see an expansion in shower coverage as a more
significant shortwave disturbance rounds the broader trough and
crosses New England with a surface reflection to our north. Dynamics
aren`t super impressive nor is the moisture (PWATs near 0.3") so not
expecting to see rain all day or everywhere, but showers will be
around potentially into Thursday. Not until Friday do we finally get
some rising heights and surface high pressure which will keep things
dry ahead of what looks to be our next widespread/heavier rainfall
system next weekend. Still a large spread in the ensemble guidance
at this timeframe but odds of widespread precip are increasing.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
Forecast Confidence Levels:
00Z update...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Tonight...Moderate Confidence.
VFR to start tonight with SW winds. An area of IFR status may
form overnight across RI and SE MA. Otherwise, MVFR CIGS work
in ahead of a cold front. light rain showers move NW to SE
tonight beginning around 08-10z in the west and 09-11z in the
east.
Tomorrow...High Confidence
MVFR/IFR with light rain showers ahead of the cold front through
12-14z, lagging until 14-16z for the Cape and Islands. Behind
the cold front, quick improvements to VFR with winds shifting
from SW to NW. Winds remain gusty all day at 20-30 knots.
Sunday Night...High Confidence
VFR. Light west winds.
KBOS TAF...High confidence in the overall TAF.
Sea breeze continues this afternoon kicking out around 22-23z.
VFR this evening. MVFR late tonight with a low chance at IFR.
Light rain showers are possible from 10-13z tomorrow. VFR behind
the cold front with gusty SW winds turning NW by the afternoon.
KBDL TAF...High confidence in TAF.
VFR today. MVFR tonight with light rain showers between 09-11z
VFR tomorrow with gusty SW winds turning NW by the afternoon.
Outlook /Monday through Thursday/...
Monday through Monday Night: VFR. Breezy.
Tuesday: VFR. Windy with gusts up to 30 kt. Slight chance RA.
Tuesday Night: VFR. Windy with local gusts up to 30 kt.
Wednesday: VFR. Breezy. Slight chance RA.
Wednesday Night: VFR. Breezy.
Thursday: VFR. Windy with local gusts up to 30 kt.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Tonight... High Confidence
Winds slowly increase out of the SW gusting 20-30 knots. Seas
increase to 3-5 feet.
Tomorrow... High Confidence
Periods of light rain showers starting around sunrise and lasting
through about noon. Winds turn WNW but remain gusty at 20-30 knots.
Seas increase to 4-7 feet.
Tomorrow night... High Confidence
Decreasing winds overnight but still gusting 15-20 knots out of the
WNW. Seas decrease to 3-5 feet.
Outlook /Monday through Thursday/...
Monday through Monday Night: Winds less than 25 kt. Areas of
seas approaching 5 ft.
Tuesday through Tuesday Night: Low risk for Small Craft
Advisory winds with gusts up to 25 kt. Areas of seas
approaching 5 ft.
Wednesday: Winds less than 25 kt. Seas locally approaching
5 ft. Slight chance of rain.
Wednesday Night: Low risk for Small Craft Advisory winds with
gusts up to 30 kt. Areas of seas approaching 5 ft.
Thursday: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Seas up to 5 ft.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
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CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 5 AM to 11 AM EDT Sunday for ANZ230-
236.
Small Craft Advisory from 2 AM to 2 PM EDT Sunday for ANZ231-
251.
Small Craft Advisory until 5 PM EDT Sunday for ANZ232>235-237.
Small Craft Advisory until 2 AM EDT Monday for ANZ250.
Small Craft Advisory until 8 AM EDT Monday for ANZ254>256.-- End Changed Discussion --
&&
$$
SYNOPSIS...BW/KP
NEAR TERM...Frank
SHORT TERM...KP
LONG TERM...BW
AVIATION...BW/KP
MARINE...BW/KP