Area Forecast Discussion Issued by NWS Boston, MA
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000
FXUS61 KBOX 141930
AFDBOX
Area Forecast Discussion
National Weather Service Boston/Norton MA
330 PM EDT Thu Mar 14 2024
.SYNOPSIS...
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Clouds increase this evening with a period of rain showers
after midnight into early Friday morning along with much cooler
high temperatures Friday.Drying out on Saturday before another
round of modest precipitation on Sunday. Cooler, but closer to
normal most of next week. Lowering risk for diurnal showers as next
week progresses, with the greatest risk Monday and Tuesday.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
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330 PM Update
Tonight
A very modest surface low-pressure system currently centered over
The Midwest will progress east along a zonal track toward the
Northeast this evening. As the system approaches, light/variable
winds associated with weak-surface high pressure building east will
shift and increase out of the southeast. This will allow higher
amounts of moisture to flow into the region ahead of the approaching
surface low. Despite the weak forcing and progressive nature of this
system, the relatively higher PWATs will allow for a period of
steady precipitation overnight and a modest soaking of rain. Model
guidance has trended toward the surface low tracking over VT/NH,
which is further north than what was being resolved yesterday. As a
result, the upper end of overcast rainfall amounts of shifted further
north as well. Areas along and north of I-90 can expect a modest
0.15 to 0.25 inches, while areas along and south of I-90 may
observed up to 0.1 inches. Not expecting rain to begin until after
midnight across the western areas and then a few hours before
sunrise across the eastern areas. Low temperatures overnight will be
bounded by dewpoints which are forecast to be in the low 40s.-- End Changed Discussion --
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
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Tomorrow
Steady rain tapers off tomorrow morning as surface low pressure
continues east over The Gulf of Maine. However, a strong-low level
version will trap the low-level moisture in place and support a
cloudy/dreary day with intermittent periods of light/drizzle and
spotty showers through early afternoon. Warm sector air mass
characterized by 925 hPa temps near 10 Celsius should support highs
ranging from the low to upper 50s. Temperatures are likely to peak
around or just afternoon however. After that time, northwest flow
kicks in and induces cold air advection which will gradually bring
temperatures down to the mid to upper 40s by tomorrow evening.
Northwest flow will be accompanied by drier air which bring
dewpoints down to the upper 30s and perhaps result in some skies
clearing prior to sunset, particularly across the western/interior
zones.
Tomorrow Night
Quiet/dry weather tomorrow night. Deep northwest flow advects
cooler/drier air over southern New England which will result in
skies gradually clearing overnight across most of the region.
Cape/Islands may see clouds linger into Saturday morning. Overnight
lows will be in the mid to upper 30s, which is slightly above normal
for mid-March.-- End Changed Discussion --
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
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Highlights
* Dry and quiet weather Sat, with a mix of sun and clouds.
* A frontal system swings through Sun bringing scattered showers.
* Still may be unsettled on Mon and Tue, but with spotty showers.
Temperatures near to below normal.
* Drier weather returns midweek.
Fairly significant pattern change during this portion of the
forecast, but not all that unusual for mid March in southern New
England. Near zonal mid level flow late this week morphs into a
modest mid level trough over the Great Lakes this weekend, which
should then move more directly overhead early next week. This trough
is then expected to linger nearby through most of next week, but
gradually weaken with time.
This near zonal flow should keep systems moving across southern New
England this weekend, along with above normal temperatures. Saturday
still appears to be the drier of the two days, but another
approaching front should bring some showers sometime Saturday night
into Sunday. Looking to be too warm for snow, so have just rain in
the forecast for now. Will keep an eye on the higher elevations with
later forecasts, as a subtle change in temperatures of a couple of
degrees may open that particular door there.
This front should not stick around long. Thinking we`ll already
start clearing out Sunday evening, and especially after midnight
Monday. While there should not be much at the surface to help focus
shower potential, the cold pool associated with the mid level trough
should be arriving, leading to the possibility of diurnal showers
Monday into Tuesday. These would be more of the hit-and-miss
variety. The more noticeable change would be the 10 degree drop in
temperatures early next week. That said, this is more of a return to
temperatures more typical of mid March, which are expected most of
next week.
By Wednesday, the atmosphere is projected to dry out just enough
where the risk for diurnal showers is lessened. However, the diurnal
clouds should linger just fine.-- End Changed Discussion --
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.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
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Forecast Confidence Levels:
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
18Z TAF Update
Through 00Z...High Confidence
VFR. Light onshore winds near the coast and light/variable
across the interior.
Tonight...High Confidence in trends, moderate confidence in
timing.
VFR persists through about 03Z at most of the terminals. Conditions
then deteriorate overnight as an area of low-pressure
approaches from the west. Ceilings falling to MVFR levels across
the interior, except BAF/BDL may remain above MVFR with cigs
around 060 feet. Terminals near the coast likely to fall to
IFR/LIFR as southeast flow advects low/marine stratus over the
terminals. Low pressure system will be accompanied by -RA
beginning around 06Z at BAF/BDL and eventually reaching BOS by
08-09Z. Modest 5 to 10 knot southeast winds.
Tomorrow...Moderate Confidence
Surface low-pressure circulation exits to the east with -RA by
about 15Z. Low-level clouds continue to linger, but we should
see any LIFR ceilings improve to at least IFR by mid-morning.
Gradual improvements to MVFR by 18-21Z and eventually back to
VFR by 00Z. Not expecting any steady periods of precipitation
after 15Z tomorrow, but there may be a few spotty showers or
intermittent periods of light drizzle. Winds shift to the
northwest after 15Z once the surface low exits east. Speeds will
be modest topping out in the 10-15 knot range.
Tomorrow Night...High Confidence.
VFR. Steady northwest winds 5 to 10 knots. Possibly some MVFR
ceilings with cloud bases from 020 to 040 over The Cape/Islands
terminals.
KBOS TAF...Moderate confidence in TAF.
Conditions begin to deteriorate around 06Z. Only moderate
confidence in ceilings falling to LIFR levels with higher
confidence of at least IFR. Low ceilings likely to persist
through the morning push before some improvements after 15Z.
Could be back to MVFR levels by early afternoon, but likely
closer to 18Z. Improvements to VFR between 21-00Z tomorrow.
KBDL TAF...High confidence in TAF.
Outlook /Saturday through Tuesday/...
Saturday: VFR.
Saturday Night: Mainly VFR, with local MVFR possible. Breezy.
Chance SHRA.
Sunday: Mainly VFR, with local MVFR possible. Windy with gusts
up to 30 kt. Chance SHRA.
Sunday Night: VFR. Breezy. Chance SHRA.
Monday: VFR. Breezy. Slight chance SHRA.
Monday Night through Tuesday: VFR. Breezy. Slight chance SHRA,
slight chance SHSN.-- End Changed Discussion --
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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.
Tonight
Low-pressure moves over southern New England tonight with steady
periods of light rain. Additionally this system will support
increasing southeasterly winds over the marine zones with speeds
ranging from 10 to 15 knots overnight. Calm seas build to 1 to 3
feet by Friday morning.
Tomorrow
Southeast winds shift to northwest late tomorrow morning/early
tomorrow afternoon as low-pressure progresses east over The Gulf of
Maine. Winds will be a bit stronger by the low ranging from 13-18
knots with gusts flirting with SCY criteria close to 25 knots at
times. Seas continue to build, but generally below SCY conditions
from 2 to 4 feet.
Tomorrow Night
Conditions look to be more quiet tomorrow night over the coastal
waters. Northwest winds diminish to more modest speeds below 10
knots. Seas come down as well but wave heights still remain in the 1
to 3 foot range by Saturday morning.
Outlook /Saturday through Tuesday/...
Saturday: Winds less than 25 kt. Seas locally approaching 5 ft.
Saturday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of seas approaching 5 ft. Slight
chance of rain showers.
Sunday: Moderate risk for Small Craft Advisory winds with gusts
up to 30 kt. Seas up to 5 ft. Chance of rain showers.
Sunday Night: Winds less than 25 kt. Areas of seas approaching
5 ft. Chance of rain showers.
Monday: Low risk for Small Craft Advisory winds with gusts up
to 20 kt. Areas of seas approaching 5 ft. Slight chance of rain
showers.
Monday Night: Moderate risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of seas approaching 5 ft. Slight
chance of rain showers.
Tuesday: Moderate risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft. Slight chance of rain
showers.-- End Changed Discussion --
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...None.
&&
$$
SYNOPSIS...Frank/BL
NEAR TERM...RM
SHORT TERM...RM
LONG TERM...Belk
AVIATION...Belk/RM
MARINE...Belk/RM