Old Res Weather

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 100528
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
128 AM EDT Tue Mar 10 2026

.WHAT HAS CHANGED...
High temperatures away from the southeast coast could threaten 
daily records for March 10th. Dreary weather Wednesday but turns
mild overnight with periods of rain. Increased winds Thursday 
with temperatures cooling off late in the week.

&&

.KEY MESSAGES...

- Sunny and quite warm today with near record high temperatures
  away from the southern coast, although quite a bit cooler with
  low clouds along the southern coast.

- Cloudy, dreary Wednesday as backdoor cold front returns north
  as a warm front. Much cooler daytime highs Wednesday northern
  MA compared to CT/RI. Then a mild night Wednesday night with
  periods of rain as cold front moves in. 

- Lingering showers ending Thu, then becoming blustery and
  turning colder in the afternoon.

- Chance for rain and elevation snow showers late Fri into Fri 
  night, then becoming windy and turning milder again late 
  Sunday into Monday with potential for widespread showers.

- Snowmelt will continue but with lack of significant rainfall 
  only minor river flooding possible.

&&

.DISCUSSION...
Key Message 1...Sunny and quite warm today with near record high 
temperatures away from the southern coast, although quite a bit 
cooler with low clouds along the southern coast.

Areas of fog and stratus to advance along the south coast and 
much of southeast New England. Fog could be locally dense at 
times but its northern extent should be stunted by at least 
modest SW winds. This moisture is trapped underneath a very 
strong temperature inversion, so even though fog is expected to 
disperse early Tue, potential exists for at least residual low 
clouds to lurk around into the afternoon as that moisture 
remains trapped beneath the inversion. This casts some 
uncertainty on how warm temps may get along the south coast and 
coastal southeast New England; although the coolest readings 
should still be recorded in these locations, in the upper 40s to
low 50s. 

Elsewhere, expecting a particularly warm day by early-March 
standards. WSW winds will combine with full sun and continued 
warm advection (850 mb temps rise to +12 to +14C) and lead to 
soaring temps. Given highs yesterday reached into the 60s with a
few spot 70 degree readings, highs today should be some 3-5 
degrees warmer and support readings well into the 60s, with 
lower to even mid 70s in the CT and Merrimack Valleys. Some 
daily records could be challenged, best chance being 
Hartford/Windsor Locks and Worcester; unlikely to see records at
Providence given cooling marine influence. Toughest call is 
Boston; should see strong enough SWly winds to keep a seabreeze 
offshore and kept highs right around 70, which is just under the
daily record. If a seabreeze does develop, highs along the 
eastern MA coast will end up being several degrees cooler. 

Key Message 2...Cloudy, dreary Wednesday as backdoor cold front 
returns north as a warm front. Much cooler daytime highs Wednesday 
northern MA compared to CT/RI. Then a mild night Wednesday night 
with periods of rain as cold front moves in. 

Challenging forecast Wed especially with respect to highs. As
the case early this AM, Tue night will be met with returning 
fog and low clouds from the southern coastal waters into 
portions of CT- RI- SE MA. Lead wave of weak low pressure passes
to our north Tue night and should reinforce cooler temps, which
will drain southward as a backdoor cold frontal boundary into 
northern and especially northeast MA. This backdoor front will 
be marked by a NE wind shift to go along with dreary conditions 
and very light rain/mist. Uncertain when this backdoor front may
slip into SNE but could occur as soon as the pre-dawn Wed 
hours. It eventually returns northward through the day on Wed as
a warm front though. As shown in higher res 2-m temps, this 
creates quite a temperature contrast across SNE, with daytime 
temps struggling to rise above the mid/upper 40s north/northeast
MA while areas south and west of the boundary could again rise 
into the mid 60s. Other than drizzle or very light rain, most of
the day is generally drier than not. 

Then a stronger wave of low pressure looks to pass to our north
Wed night, but strong warm and moist advection takes place 
ahead of this frontal system's associated cold front on SWly low
level jet nearing 50 kt. PWATs rise to as much as 1.5" Wed 
night and 850 mb temps continuing to warm to at least +14C. Even
some elevated instability, as can be expected in these 
nighttime strong warm/moist advection regimes, although its 
scope varies between the GFS/NAM quite a bit. 00z NAM profiles 
are pretty impressive and could support thunder but much more 
paltry in the GFS. Raised PoPs to likely for Wed night ahead of 
the cold front. Not expecting a significant amount of QPF with 
this wave but this will need to be monitored.

KEY MESSAGE 3...Lingering showers ending Thu, then becoming blustery 
and turning colder in the afternoon.

Cold front will be moving through SNE Thu morning then offshore in 
the afternoon. Pre-frontal showers expected and timing of FROPA will 
determine how quickly the showers exit. Best chance of showers in 
the morning will be in the east where later FROPA arrival, then 
drying out in the afternoon as PWATs crash. Strong cold advection 
behind the front so after a mild start temps will fall from the 50s 
in the east through the 40s in the afternoon, while interior 
locations will see temps fall through the 40s and into the 30s 
higher elevations. The strong cold advection will also result in 
gusty W-NW winds. Soundings show a relatively shallow mixed layer 
but excellent mixing will support gusts 25-35 mph. Winds will slowly 
diminish Thu night with lows dropping into the 20s.

KEY MESSAGE 4...Chance for rain and elevation snow showers late Fri 
into Fri night, then becoming windy and turning milder again late 
Sunday into Monday with potential for widespread showers. 

Another fast moving northern stream shortwave and attendant clipper 
system will track to the north late Fri into early Sat. Bulk of the 
QPF will be to the north but modest low level jet and increasing 
moisture suggest a period of rain and elevation snow showers will 
impact the region late Fri into Fri night, especially northern MA. 
Minor snow accums are possible over the Berkshires. Then drying out 
Sat behind the cold front as much drier air moves in.

A more amplified trough approaches from the west Sunday into Monday 
with a stronger low level jet advecting anomalous PWATs (approaching 
1.5") northward into SNE. This will likely bring a more widespread 
rainfall event Sun night into Monday and can't rule out locally 
heavy rainfall given the LLJ and PWAT anomalies. Something that will 
need to be monitored as rivers and streams will be running high from 
the recent accelerated snowmelt. Any heavy rainfall could introduce 
flooding concerns. Another surge of mild air and gusty winds 
expected Sun night into Mon with the southerly low level jet. 

KEY MESSAGE 5...Snowmelt will continue but with lack of significant 
rainfall only minor river flooding possible.

Snowmelt will become more accelerated Wednesday night as dewpoints 
climb into the 50s and most of the snowpack outside of the 
Berkshires will likely be depleted by Thursday. However, we are not 
expecting much rainfall Wed night into Thu so only expecting minor 
flood stages to be observed as a worst case scenario. Guidance 
continues to indicate the most likely spots to see flooding are 
along the Connecticut River by next weekend with addition of S. RI 
rivers by early next week.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
Forecaster Confidence Levels...

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

06z TAF Update: 

Through 12z Tuesday: High confidence.

VFR for most airports away from the southeast coast. For the
south coast, Cape and Islands, LIFR-VLIFR fog/IFR-LIFR stratus
prevails thru sunrise, which could make it as far north as PVD-
PYM. SW winds around 5-10 kt.

Tuesday: High confidence, though moderate along the south coast. 

Areas IFR-VLIFR in fog/stratus along the south coast/Cape and
Islands initially should trend to a IFR-MVFR stratus early Tue
AM; categories are still in some question here as sub-VFR 
stratus could lurk around for quite a while as moisture is 
trapped underneath very strong thermal inversion. VFR elsewhere 
with SW winds around 5-10 kt; winds too strong for seabreeze to 
develop at BOS. 

Tuesday Night: Moderate confidence. 

IFR-LIFR fog/stratus should expand northward from the waters 
into at least the south coast/Cape and Islands. Conditions 
should be VFR for most of the time elsewhere; however a backdoor
cold front could southward as soon as 08z Wed and bring at 
least MVFR- IFR ceilings and increasing NE winds to BED-BOS-ORH-
PVD. Timing of this backdoor front is still unclear. 

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Wednesday through Saturday/...

Wednesday: MVFR/IFR conditions possible. Breezy. Slight chance
RA, patchy BR.

Wednesday Night: Mainly VFR, with local IFR possible. Breezy.
Chance RA.

Thursday: VFR. Windy with areas of gusts up to 30 kt. Chance
RA.

Thursday Night through Friday: VFR. Breezy. 

Friday Night: Mainly VFR, with local MVFR possible. Windy with
areas of gusts up to 30 kt. Chance RA, chance SN.

Saturday: VFR. Windy with local gusts up to 30 kt. 

&&

.MARINE...
Forecaster Confidence Levels...

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

Sub-SCA wind and wave conditions prevail through the daytime 
hours Wed. SW winds around 10-15 kt with seas 2-3 ft, though 
seas build to 2-4 ft Wed. Main concerns for mariners are the 
risk for nighttime fog both overnight and again Tue night into 
Wed, and also a NE windshift for mariners navigating the 
northern waters Wed. 

SCAs likely to be needed Wed night as seas rise over 5 ft on all 
waters. Gusts could also punch into SCA range but more than 
likely to be tempered by a strong inversion.

Outlook /Wednesday through Saturday/...

Wednesday: Winds less than 25 kt. Seas locally approaching
5 ft. Slight chance of rain, patchy fog. 

Wednesday Night: Strong winds with areas of gusts up to 30 kt.
Areas of rough seas. Chance of rain. 

Thursday: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Areas of rough seas. Chance of rain. 

Thursday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of rough seas. 

Friday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Areas of seas approaching 5 ft. 

Friday Night: Strong winds with gusts up to 35 kt. Areas of
rough seas. Chance of rain. 

Saturday: Moderate risk for Small Craft Advisory winds with
areas of gusts up to 30 kt. Areas of rough seas. 

&&

.CLIMATE...
Record highs for Tuesday, March 10th...

BOS...71...1878
PVD...72...2016
BDL...72...2016
ORH...67...2020

Average high for 3/10 is 40-45.

&&

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

&&

$$

DISCUSSION...KJC/Loconto
AVIATION...KJC/Loconto
MARINE...KJC/Loconto
CLIMATE...Loconto/JWD