BOX issues Area Forecast Discussion (AFD) at May 19, 7:33 PM EDT
419
FXUS61 KBOX 192333
AFDBOX
Area Forecast Discussion
National Weather Service Boston/Norton MA
733 PM EDT Mon May 19 2025
.SYNOPSIS...
Unseasonably cool high temperatures for the remainder of the work
week that will run 10 to 20 degrees below normal! A late season
Nor'eater likely brings a cold windswept heavy rain to the region
late Wednesday into early Friday. The brunt of the storm appears to
be Thursday when wind gusts of 40-50+ mph will be possible along the
coast with pockets of minor coastal flooding possible. The soaking
rain will likely come to an end Friday morning...but a few showers
will remain possible at times through the Holiday Weekend.
Temperatures will slowly moderate...but still remain below normal
into the weekend.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Key Messages:
* Cloudy and blustery conditions continue through the night with
nothing more than a few brief showers in NE MA this evening
* Overnight lows dropping into the 40s
Details:
A few brief showers will clip northeast MA this evening from
some shortwave energy being sent southward from the main upper
level low near Nova Scotia. Otherwise...rather cloudy, breezy
and chilly tonight.
The upper level low over Nova Scotia continues to be the main driver
behind the NW flow - advecting martime-polar air into southern New
England. While the low hasn't retrograded, it hasn't moved much in
general. This has allowed for more and more clouds to move in over
the CWA as well as keeping winds (and gusts) on the higher side.
Expecting temperatures tonight to bottom out in the low to mid
40s... possibly even the high 30s in the northern Berkshires.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
Key Messages:
* Periods of sun early Tue, then onshore flow and lower cloudiness
moves in from the Gulf of Maine by afternoon. Could be some
drizzle or light rain at times in the lower clouds. Unseasonably
cool, with highs in the mid 50s coastal MA to the upper 50s to mid
60s elsewhere.
Details:
Tuesday:
Upper low over Nova Scotia finally pushes offshore and allows for
some relaxing of the pressure gradient, and consequently, easing the
winds. It's possible western MA/northern CT could see some good
sunshine in the morning, but lots of moist onshore flow throughout
the day will keep eastern MA & RI in overcast skies. Moisture looks
pretty shallow, but the depth of it does increase a bit by
afternoon, with drier air aloft... could lead to some off-and-on
periods of drizzle over the Cape and immediate coast as the low
cloud deck comes in. But the majority of the time should end up dry.
Regarding temps, CT Valley probably has the best shot at seeing the
mid 60s, but getting into the low 60s elsewhere could be a tall ask,
and the eastern MA coast could struggle to even get to the high 50s.
For context, our typical nighttime lows for this time of year run
around the upper 40s to low 50s.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Key Messages...
* Unseasonably cool especially with high temps for the remainder of
the week with some improvement this weekend into Memorial Day
* Nor'easter will bring a cold heavy windswept rain late Wed into
early Friday with Thu afternoon temps in the mid 40s to lower 50s
* ENE wind gusts of 40-50+ mph possible along the coast Thu with
perhaps some pockets of minor coastal flooding during high tide
* The widespread rain comes to an end Fri morning...but a few
showers will remain possible at times for the Holiday Weekend
Details...
Vigorous shortwave energy will dive southeast of the Great Lakes for
the latter half of this week. This process will result in
cyclogenesis across the mid-Atlantic states setting the stage for a
late season Nor'easter. While there is still uncertainty on the
track...the models have come into somewhat better agreement at 12z
especially the GFS model which had been a southern outlier. Odds now
favor this low pressure system tracking inside the
Benchmark...likely bringing a cold windswept heavy rain event in the
late Wed into early Fri time frame with the worst of it being on Thu.
We do think that much of the daylight hours Wed may turn out dry
with just a few spot showers given onshore flow...but Thu looks like
a washout. Latest 12z guidance indicating a good shot at 1-2 inches
of rain with perhaps locally higher amounts.
The other issue will be the potential for ENE wind gusts of 40-50+
mph along portions of the coast...especially the Cape and Islands. A
lot of the guidance now showing an 850 mb E LLJ of 50 to 60 knots
and Bufkit soundings indicate good mixing...so we certainly may need
to consider wind headlines for parts of the coast. In
addition...while astronomical tides are not that high the potential
exists for 1.5 to 2.5 foot storm surge. If this occurs...we may see
some minor coastal flooding along the eastern MA coast onto
Nantucket during the Thu high tide cycle depending on specific
timing and the magnitude of the winds/wave heights.
This low pressure system will lift off into the Canadian Maritimes
Fri into the Holiday Weekend. This will bring an end to the threat
for the widespread rain Fri morning. However...a deep upper level
anomalous trough will be slow to depart into the Holiday Weekend.
This will bring us the risk of a few showers at times through the
weekend...but it will not be a washout.
Breaking the temperature forecast down below...high temps on Wed
will be held mainly in the 50s perhaps near 60 in the CT River
Valley. The chilliest day of the week looks to be Thu with the cold
windswept rain and afternoon temps only in the middle 40s to the
lower 50s! By the weekend...much of the region may finally see highs
into the 60s especially by Sun. And by Mon...we may finally break 70
in spots. So the improvement will be slow, but it will gradually
happen.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
00z TAF Update...
Tonight...High Confidence.
A broken deck of mainly VFR ceilings will persist tonight...but
some marginal MVFR ceilings may work onto the Cape and Islands
toward daybreak. NW wind gusts of 20 to 30 knots should diminish
a tad overnight into the 15 to 25 knot range.
Tuesday...High Confidence.
Mainly a broken deck of VFR ceilings, though we will have to
watch for periods of MVFR ceilings mainly for east coastal MA,
Cape/Islands and perhaps into RI during the 2nd half of the day
as winds become NE. N winds lighten and become NE/ENE in
eastern MA and RI after 15z. Gusts to 25 knots on Tue will be
confined to mainly the Cape and Islands.
Tuesday night...Moderate Confidence.
A broken deck of clouds that will trend downward to mainly MVFR
levels from east to west as the night wears along. Light ENE
winds.
BOS TAF...High Confidence in TAF.
BDL TAF...High Confidence in TAF.
Outlook /Wednesday through Saturday/...
Wednesday: Mainly VFR, with areas MVFR possible. Breezy. Slight
chance SHRA.
Wednesday Night: MVFR/IFR conditions possible. Windy with local
gusts up to 30 kt. Chance SHRA.
Thursday: Mainly MVFR, with areas IFR possible. Windy with
gusts up to 35 kt. RA.
Thursday Night: MVFR/IFR conditions possible. Windy with gusts
up to 35 kt. RA.
Friday: MVFR/IFR conditions possible. Windy with local gusts up
to 30 kt. Chance SHRA.
Friday Night: Mainly VFR, with local IFR possible. Chance SHRA.
Saturday: MVFR/IFR conditions possible. Breezy. Chance SHRA.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Tonight through Tuesday night...
NW gusts continue to range between 25-30 kt, and will continue
to be the case today, with a slower decrease in NW gusts to
around 20 kt. Small craft advisories remain posted on all
waters.
We should see more N/NE winds develop on Tuesday around 15-20 kt,
which could be accompanied by periods of drizzle or light rain
showers but not enough to restrict visibility.
Outlook /Wednesday through Saturday/...
Wednesday: Winds less than 25 kt. Seas locally approaching
5 ft. Slight chance of rain showers.
Wednesday Night: Low risk for gale force winds with gusts up to
35 kt. Areas of seas approaching 5 ft. Chance of rain showers.
Thursday: Moderate risk for gale force winds with gusts up to
40 kt. Rough seas up to 15 ft. Rain. Local visibility 1 to
3 nm.
Thursday Night: Low risk for gale force winds with gusts up to
40 kt. Rough seas up to 16 ft. Rain.
Friday: Moderate risk for Small Craft Advisory winds with gusts
up to 30 kt. Rough seas up to 13 ft. Chance of rain showers.
Friday Night: Winds less than 25 kt. Local rough seas. Chance
of rain showers.
Saturday: Winds less than 25 kt. Seas locally approaching 5 ft.
Chance of rain showers.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 11 PM EDT this evening for ANZ230.
Small Craft Advisory until 5 AM EDT Tuesday for ANZ231>235-237-
250-251-254>256.
&&
$$
SYNOPSIS...Frank/McMinn
NEAR TERM...Frank/McMinn
SHORT TERM...McMinn
LONG TERM...Frank
AVIATION...Frank/McMinn
MARINE...Frank/McMinn
Source: BOX issues Area Forecast Discussion (AFD) at May 19, 7:33 PM EDT (https://mesonet.agron.iastate.edu/p.php?pid=202505192333-KBOX-FXUS61-AFDBOX)
----------------
If I'm using your data in a way that is against your terms please email the team at "threatweb@pupswoof117.com"! I am a bot who will not respond in the comments at all and is only designed to post RSS feeds!