Area Forecast Discussion Issued by NWS Boston, MA
000
FXUS61 KBOX 150549
AFDBOX
Area Forecast Discussion
National Weather Service Boston/Norton MA
149 AM EDT Fri Mar 15 2024
.SYNOPSIS...
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.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
940 PM Update...
* Brief period of showers after midnight esp north of I-90
The previous forecast is on track. Shortwave/low pressure across
the eastern Great Lakes moves across New York and southern New
England through early Friday morning. The 850 mb low will be
passing across northern New England...so expect the
steadiest/heaviest rain to pass to our north where better
overrunning resides. Nonetheless...many locations in our region will
see a brief period of showers after midnight especially north of
I-90. There is a second band of precipitation to the south in
Ohio and western PA. This was more convectively induced and
responsible for severe weather/tornadoes that are currently
impacting parts of Ohio. This activity will weaken considerably
as it moves east into a less favorable environment.
Nonetheless...a few showers may survive but these may tend to
pass to our south although could graze areas near the south
coast.
Overall...a brief period of showers impacts the region after
midnight with the focus across northern MA. Overnight low temps
should range from the upper 30s to the middle 40s.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/...
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.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
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.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
Forecast Confidence Levels:
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
06z TAF Update...
Today...Low Confidence.
A low confidence forecast in terms of coverage and timing of low
clouds. Appears the main risk of IFR-LIFR conditions through
daybreak will be along the coast with light/moist onshore flow.
Otherwise...mainly VFR conditions inland from the coast with a
band of brief rain showers crossing the region especially north
of I-90 through daybreak. As this wave of low pressure works
across southeast New England this morning...low clouds may
temporarily scour out near the Cape/Islands. However...behind
the departing wave of low pressure winds shift to the N at 10 to
15 knots with some 20+ knot gusts possible. This will allow for
MVFR-IFR ceilings to overspread much of the region east of the
CT River Valley through the morning with the lowest conditions
along the eastern MA coast. Across western MA/CT conditions may
be VFR to occasionally MVFR.
Later shifts will have to monitor low cloud trends/timing today
for possible refinements given the uncertainty in the forecast.
Tonight...High Confidence.
Mainly MVFR ceilings will linger into the evening across eastern
New England...but VFR conditions should overspread this region
from the west as the night wears along. Light/Calm NNW winds.
Saturday...High Confidence.
VFR. SW winds 5-10 knots but localized sea breezes developing
during the afternoon along portions of the immediate coast.
KBOS TAF...Low confidence in TAF. Difficult forecast in terms of
timing/duration of low clouds. Current thinking is that IFR to
perhaps even LIFR conditions impact the terminal from near
daybreak into the afternoon...mainly the result of low clouds.
KBDL TAF...Moderate confidence in TAF.
Outlook /Saturday Night through Tuesday/...
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.
&&
.MARINE...
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 Small Craft Advisory (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 kts. Seas come down as well but wave heights still remain in
the 1 to 3 foot range by Saturday morning.
Outlook /Saturday Night 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.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...None.
&&
$$
SYNOPSIS...Frank/BL
NEAR TERM...Frank
SHORT TERM...RM
LONG TERM...Belk
AVIATION...Frank/Belk
MARINE...Belk/RM