Old Res Weather

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 071113
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
613 AM EST Fri Nov 7 2025

.SYNOPSIS...
High pressure over the mid-Atlantic states builds offshore of
southern New England today. A cold front should bring some 
showers tonight into Saturday, followed by dry and mild weather
Saturday afternoon. Area of low pressure and cold front bring a
round of rain and gusty southerly winds into early Monday, 
followed by much chillier weather later Monday and especially by
Tuesday. Slight improvements in temperatures Wednesday before a
reinforcing trough arrives later next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
250 AM Update:

Key Messages: 

* Increasing mid-level cloud canopy today with SW breezes. Highs in 
  the 50s/near 60.

* High astro tides could result in minor splashover along the 
  North Shore, Boston Harbor and south-facing portions of 
  Barnstable County around the noontime high tide. 

Details:

Ridge of high pressure is analyzed early this morning thru western 
New England and into VT early this morning. There has been just 
enough of residual WNW winds in eastern/southeast MA to support a 
more wider variation in observed temps (29 degrees here at the WFO, 
but still some areas in the upper 30s to the mid 40s); but temps 
have really bottomed out in interior Southern New England in 
vicinity of the ridge axis, with ORE down to 24 degrees, with mid 
20s to near freezing more common. Trend will be for continued 
slackening of winds and widespread 20s to lower/mid 30s should 
become more common by the pre-dawn hours. However a strong belt of 
500 mb westerly flow is allowing for a shield of mid to high clouds, 
the leading edge of which are now into central NY. This is heralding 
a frontal wave moving across the Gt Lakes, set to arrive into 
Southern New England tonight.

Looking at a chilly start to the day, with sfc ridge gradually 
moving eastward/offshore into the late-AM. Trending toward a mid to 
high level overcast too as mid to high clouds continue to fill the 
scene from the west. Finally, today also start to turn pretty breezy 
with increasing SW winds in the 10-15 mph range and gusts 20-25 mph, 
limited to an extent by more shallow mixing depths. Highs today in 
the 50s, with perhaps some readings near 60 along the southern 
coast. 

In terms of headlines...we did issue a coastal flood statement for 
the early afternoon high tide around 1200-1230 PM for the 
coastal areas in and around Boston Harbor and the North Shore; 
we also issued the same for Barnstable County along shoreline 
roads with southern exposures. The biggest limiting factor  
with regard to the coastal flooding, and it's a big one, is that
the surge is pretty low. But with that said, astro tides coming
out of the so-called Beaver Full Moon are quite high: Boston's 
astro tide around 1200 PM today is at 12.13 ft MLLW, and flood 
stage is 12.5 ft. There may end up being some minor overwash 
just due to the astro tide, but we sided towards a statement vs 
advisory because of the more offshore/SW flow limiting storm 
surge values. In Barnstable County, shoreline roads exposed to 
the south have the better chance at seeing minor overwash, which
includes the recently-added tidal gage in Hyannisport, but 
could also include the bay side of Provincetown to Truro.

&&

.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
250 AM Update:

Key Messages: 

* Overcast with frontal rain showers between 7pm to midnight for 
  areas north/west of I-95. Rain amts less than a quarter inch, 
  before drying out overnight. 

* Showers, low risk for thunder and lightning overnight for SE MA, 
  Cape and Islands and nearby waters after midnight. Off-and-on rain 
  showers could linger into Sat morning for the Cape, but drying out 
  by Sat late morning/noontime. 

* Mild highs on Sat for November, in the mid 60s but with more 
  seasonable lows for Sat night.

Details: 

Tonight: 

Frontal boundary gradually works its way into Southern New England 
tonight, associated with an approximate 992 mb sfc cyclone which 
treks through the St. Lawrence River Valley. Expecting a period of 
light rain showers working through most communities along and 
northwest of I-95 between 8 pm and midnight, with rain amts in these 
areas a quarter inch or less. Enough such that if you have evening 
plans, you'll have some rain to dodge, but really nothing impactful. 
Drying out tonight for these areas overnight with winds becoming 
lighter westerly.

Things get somewhat more interesting after midnight in southeastern 
MA and perhaps into coastal RI and the offshore waters. 500 mb progs 
off the global models show trough energy splitting into a northern 
stream thru Quebec, but a trough in the southern branch in the 
central Appalachians/VA Piedmont region allows the sfc frontal 
boundary to sag SE or even stall into early Sat AM. Modest lift from 
this shortwave with ribbon of elevated instability atop stable sfc 
layer in the southeast coastal waters (total-totals around 50 
units/Showalters around 0 to -1) could allow for development of 
heavier showers and some lightning/thunder between midnight to 6 AM. 
Not expecting severe weather but some lightning flashes could be 
possible around Buzzards Bay/Cape Cod and the Islands so left a 
token mention of thunder for these areas. This is also reflected in 
some simulated reflectivity output across the convection-permitting 
guidance but the exact placement is more varied. Rain amts could be 
as much as a half-inch in isolated instances but should be more 
generally in the quarter to third of an inch range. Clouds and rainy 
conditions linger for the Cape and Islands into Sat AM. 

In all areas, it's an otherwise pretty mild night by November 
standards, with fcst readings in the 40s, perhaps near 50 out over 
the Cape.  

Saturday and Saturday Night: 

Fcst challenge for Sat is how soon will residual showers associated 
with slowing frontal boundary linger over southeast New England. The 
steadiest rains will have ended, but could see clouds and off-and-on 
showers continuing into a good part of the morning before trudging 
eastward/offshore and drying out. The timing there still is subject 
to adjustment, though I'd plan on there being some showers if your 
plans take you to Cape Cod/the Islands Saturday morning. But dry
elsewhere in Southern New England. All things considered it 
ends up being a pretty mild Sat for November, as the cold 
advection doesn't really bleed into our area until later in the 
afternoon and evening hours. Even post- frontal, mostly sunny to
partly cloudy and highs on Sat probably reach the low to mid 
60s (50s/low 60s Cape Cod/Islands). 

Modest cold advection takes place Sat evening with a light west 
wind, which eventually turns more onshore/NEly in response to the 
next wave of low pressure moving thru the OH Valley. Seasonable lows 
in the mid 30s northern MA, to the upper 30s/low 40s south 
coast/Cape and Islands, and upper 30s in between.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Key Messages:

* Low pressure brings a period of rain and gusty winds Sunday into 
  Monday. 
* Increasing confidence in below average temperatures early next 
  week.
* Minimal chances for precipitation outside of some showers and 
  isolated elevation flurries through much of next week.

A fast-moving system approaches from the Great Lakes Sunday into 
early Monday. Primary area of low pressure tracks through eastern 
Great Lakes and a weaker secondary low tracks near or just offshore 
of southern New England. 1"+ PWAT values ahead of the system 
indicate the potential for a period of moderate to heavy rain. 
Thankfully, the low will be progressive and somewhat weak in nature 
so not expecting much in the way of freshwater flooding. The 
50th percentile NBM has a widespread 0.25-0.5 inches of precip 
for the event while the 90th percentile worst case scenario 
paints a widespread 1-1.25" across the CWA. 

One other concern Sunday afternoon is some minor coastal flooding 
along the Sound side of Cape Cod (Falmouth) due to lingering high 
astronomical tides and possible brisk S/SE flow ahead of secondary 
low. However, that is highly dependent upon the exact track of the 
low so there is a lot of uncertainty right now. It's more likely 
that the storm tide stays below flood stage but something to keep an 
eye on. Nantucket is also showing a similar potential for borderline 
minor flooding but that is more unlikely given S/SE flow.

Departing low pressure brings a few widely scattered showers and a 
gusty northwest wind Monday. Bigger story for the start of the week 
will be below average temperatures as a deep trough digs over the 
eastern CONUS. In fact, we will likely see some of the coldest air 
so far this season as 850mb temps plunge well below freezing. Even 
9250mb temps likely stay below freezing translating to surface 
temperatures in the upper 30s to low 40s.

Pattern going into the midweek looks to be mainly dry save for some 
scattered rain and elevation snow showers with a few northern stream 
disturbances pass N of New England. It could be breezy as they pass 
with a steep pressure gradient developing as surface high pressure 
builds across the southeastern CONUS. Signals for cooler weather 
continue into the late week with a -NAO pattern advertised to 
persist.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
Forecaster Confidence Levels...

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

12z TAF Update: 

Today: High confidence. 

VFR, increasing midlevel cloud canopy. S winds around 5-8 kt to
start, but picks up to around 12-15 kt with gusts to 25 kt by
early aftn. 40 kt jet at 2000 ft but should be gusty enough such
that low-level shear isn't anticipated. 

Tonight: Moderate confidence. 

Frontal boundary brings 5-6 SM visby RA and MVFR ceilings.
Start timing for western airports around 01-03z, around 02-05z 
ORH/PVD/BOS/BED, after 06z Cape and Islands with low chance of 
TS. While western terminals should clear out after 07z, frontal
boundary hangs up and slowly moves east, which could delay 
cessation of rain showers and arrival of improving ceilings for
eastern terminals until Sat. Winds become SW around 10-12 kt 
with lesser gusts, potential exists for low-level shear if gusts
ease in showers. 

Saturday: Moderate confidence. 

Conditions could still be sub-VFR at BOS, PVD and the Cape
airports by 12z Sat but with slowly improving conditions to VFR
thru 16z (if not sooner). Winds shift to W around 5-10 kt. 

Saturday Night: High confidence. 

VFR. Easing WNW winds (calm at times near midnight), then shift
to light NE by 12z Sun.

KBOS Terminal...High confidence in TAF. 

KBDL Terminal...High confidence in TAF.

Outlook /Sunday through Tuesday/... 

Sunday: Mainly VFR, with local MVFR possible. Breezy. RA
likely.

Sunday Night: Mainly MVFR, with areas IFR possible. Breezy. RA,
isolated TSRA.

Monday: MVFR/IFR conditions possible. Breezy. RA likely.

Monday Night: VFR. Breezy. Chance RA, slight chance SN.

Veterans Day: VFR. Windy with gusts up to 35 kt. Slight chance
RA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Today and Tonight: Moderate confidence.

SCAs take effect at 17z as SW gusts pick up to around 25-30 kt.
Winds are very close to gale force and it wouldn't surprise if
there is a gale force gust or two at times. Think SCAs best
reflect expected conditions this aftn and tonight, but an 
upgrade to Gale Warnings could be considered later today. Seas 
3-5 ft this morning but rebuild to 6-10 ft over outer waters 
tonight.

Rain develops tonight on most waters, with possibility of
thunder/lightning over the waters near/south of the Islands
after midnight. 

Saturday and Saturday Night: High confidence.

W winds around 10-15 kt Sat, becoming light NE overnight. SCAs
may need to be extended into Sat as seas slowly subside. 

Outlook /Sunday through Tuesday/... 

Sunday: Winds less than 25 kt. Seas locally approaching 5 ft.
Chance of rain. 

Sunday Night: Winds less than 25 kt. Seas up to 5 ft. Rain,
isolated thunderstorms. 

Monday: Winds less than 25 kt. Seas up to 5 ft. Rain likely. 

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

Veterans Day: Moderate risk for gale force winds with local
gusts up to 45 kt. Rough seas up to 14 ft. Chance of rain.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from noon today to 7 AM EST Saturday for 
     ANZ230-236.
     Small Craft Advisory from noon today to 10 AM EST Saturday for 
     ANZ231>235-237-250-251-254>256.

&&

$$

SYNOPSIS...Loconto/FT
NEAR TERM...Loconto
SHORT TERM...Loconto
LONG TERM...FT
AVIATION...Loconto/FT
MARINE...Loconto/FT