Old Res Weather

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 300606
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
106 AM EST Wed Nov 30 2022

.SYNOPSIS...

A strong cold front approaches Wednesday bringing a period of heavy 
rain along with strong to potentially damaging wind gusts late 
Wednesday into Wednesday evening. Windy conditions continue on 
Thursday along with chilly temperatures. Another strong cold front 
will bring a period of rain and strong wind gusts Saturday into 
Saturday evening with dry and blustery conditions returning on 
Sunday. More showers are possible sometime Monday into Tuesday.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...

950 PM Update...

Previous forecast is on track. High pressure slowly moves off 
the coast overnight as a strong shortwave digs eastward across 
the Great Lakes. This will allow a southerly LLJ and warm 
advection processes to kick in aloft; resulting in low-mid level
cloudiness increasing particularly towards daybreak. Current 
temps only a touch below the expected lows in the outlying
locations. Lows should bottom out in the middle 20s to the 
lower 30s across the typically colder spots. Temps will level 
off and even rise overnight...particularly along the immediate 
coast toward daybreak as southeast winds allow all these 
locations to warm into the 40s.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...

Tomorrow and Tomorrow Night...

* Showers develop ahead of an approaching cold front tomorrow.

* Strong cold front pushes through the region tomorrow evening with 
  moderate to heavy rainfall and potentially damaging wind gusts.

Winds increase out of the south throughout the day tomorrow as 
a very strong surface cold front approaches from the west. WAA 
related precipitation will overspread southern New England from 
west to east beginning late tomorrow morning. Precip gradually 
spreads east and reaches the coast by early afternoon. Winds 
begin to ramp up just ahead of the front by mid-afternoon 
tomorrow. Impressive low-level jet with 70 knots at 925 hPa will
support surface wind gusts from 40 to 50 mph across much of 
southern New England. A wind advisory will go into effect for 
the entirety of southern New England beginning at 11AM for 
western MA/CT and 1PM for the rest of southern New England.

Heaviest rainfall will occur between roughly 3 and 10 PM as the 
leading edge of the cold front pushes through the region. This will 
also coincide with the period of strongest wind gusts. The front 
exits east of the region by 10 PM bringing an end to precipitation 
and the strongest winds. West/northwest winds remain fairly gusty 
tomorrow night, especially across the higher terrain of western MA 
where the advisory will remain in effect through Thursday afternoon. 
There is a likelihood that the atmosphere decouples for a short time 
tomorrow night. Thus, there will likely be a period where wind gusts 
are sub-advisory level. Gusts will pick back up as the sun rises on 
Thursday morning.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...

Highlights...

* Strong winds continue on Thursday, diminishing overnight

* Dry and seasonable Friday, then another round of rain and strong 
  winds move in Saturday and Saturday evening with mild conditions

* Dry and blustery Sunday

* Another period of showers possible sometime Monday into Tuesday
 
Thursday into Friday...

Deep trough lifts out Thu with very dry air moving in under W/NW 
flow with PWATs decreasing to less than 0.25". Some diurnal clouds 
are expected under the cold pool aloft, especially interior 
otherwise partly to mostly sunny skies. Strong west wind gusts will 
be the main story for Thu. A deep and very well mixed boundary layer 
with 1000-850 mb lapse rates approaching dry adiabatic will help to 
bring down a lot of the 850 mb winds. The strongest wind gusts up to 
45-55 mph will be focused across the higher terrain in MA with 30-40 
mph gusts closer to the south coast. Wind advisories will continue 
for central and western MA. Below normal temps with highs upper 30s 
to lower 40s elsewhere. 

Gusty winds Thu evening will gradually diminish overnight then shift 
to SW during Fri as high pres moves off the mid Atlc coast. Temps 
moderate a bit Friday to near seasonable normals under abundant 
sunshine as high pres moves off the mid Atlc coast.  

Saturday into Sunday...

Another robust mid level shortwave and strong cold front will be 
approaching from the Gt Lakes. This will bring another round of 
showers Sat into Sat evening along with gusty pre-frontal SW winds. 
The low level jet is a bit weaker than tomorrow evening's jet but 
mixing potential is greater so could see advisory level wind gusts, 
especially across SE New Eng. SW flow will bring mild air into SNE 
Sat with temps reaching into the 50s with some 60+ degree readings 
possible across RI and eastern MA.

The cold front sweeps across SNE Sat evening bringing an end to the 
rain, followed clearing skies overnight through Sunday as much drier 
air moves in. Blustery conditions Sun with near seasonable temps. 

Monday into Tuesday...

Active pattern continues in developing strong -NAO pattern as 
anomalous Greenland ridge develops. Broad but deepening upper trough 
sets up over central Canada to northern Plains with shortwave energy 
approaching from the west. At this time, an inland storm track is 
favored given strength of SE ridge and SW flow aloft which suggests 
mainly rain for ptype. The most uncertainty is with respect to the 
timing of rainfall. ECMWF is dry into Tue while GFS/Canadian are 
wet. EPS ensembles support a mainly dry day Mon then unsettled and 
wet Mon night/Tue. It will likely take a few more days to pin down 
the timing.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...

Forecaster Confidence Levels:

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

06Z TAF Update...

Today & Tonight...High Confidence in trends with moderate 
confidence in timing. 

Low end VFR-MVFR conditions very early this morning will trend
towards mainly MVFR with localized IFR conditions as the morning
wears along. The exception will be near and especially 
southeast of the Boston to Providence corridor...where VFR 
conditions may linger at times into the afternoon. 

Band of widespread rain arrives later today from west to 
east...roughly between 16z and 20z and briefly fall heavy resulting
in low end MVFR-IFR conditions along with some LLWS. Southerly 
winds will pickup as well with brief 35 to 45 knot wind gusts 
sweeping across the region. The back edge of the rain will 
quickly cross the area between 22z and 02z with a wind shift to
the W and another brief period of 35-45 knot wind gusts.

VFR conditions quickly return to all areas by mid to late
evening. W winds will still gust to between 20 and 30 knots and
up to 35 knots in a few of the typical spots that tend not to
decouple.

Thursday...High Confidence. 

VFR conditions despite W wind gusts of 30 to 40 knots with the
strongest of those winds north of the CT/RI border. A few gusts
up to 45 knots are possible in portions of western and central
MA.

Outlook /Thursday Night through Sunday/... 

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

Friday: VFR. 

Friday Night: VFR. Breezy. 

Saturday: Mainly MVFR, with local IFR possible. Windy with
gusts up to 35 kt. Chance SHRA.

Saturday Night: Mainly VFR, with areas MVFR possible. Windy
with gusts up to 35 kt. Chance SHRA.

Sunday: VFR. Breezy.

&&

.MARINE...

Forecaster Confidence Levels:

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

Tonight through Tomorrow Night

High pressure supports relatively quiet conditions across the 
coastal waters tonight. Winds will gradually strengthen out of the 
southeast early tomorrow morning as the pressure gradient 
strengthens in response to an approaching cold front. Gale force 
winds develop by tomorrow afternoon as a strong cold front pushes 
over the coastal waters with moderate to heavy rainfall. Winds shift 
to the west/northwest behind the front tomorrow evening and continue 
to produce gale force gusts through Thursday afternoon.

Outlook /Thursday Night through Sunday/...

Thursday: Strong winds with gusts up to 35 kt. Rough seas up to
10 ft. 

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

Friday: Winds less than 25 kt. Seas locally approaching 5 ft. 

Friday Night: Winds less than 25 kt. Areas of seas approaching
5 ft. 

Saturday: Strong winds with gusts up to 30 kt. Areas of rough
seas. Rain showers likely. 

Saturday Night: Moderate risk for Small Craft Advisory winds
with gusts up to 30 kt. Rough seas up to 10 ft. Chance of rain
showers. 

Sunday: Winds less than 25 kt. Areas of rough seas.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Wind Advisory from 11 AM this morning to 9 PM EST this evening 
     for CTZ002>004.
MA...Wind Advisory from 11 AM this morning to 5 PM EST Thursday for 
     MAZ002-003-008>011.
     Wind Advisory from 1 PM this afternoon to 5 PM EST Thursday 
     for MAZ004-012-026.
     Wind Advisory from 1 PM this afternoon to 1 AM EST Thursday 
     for MAZ005>007-013>024.
RI...Wind Advisory from 1 PM this afternoon to 1 AM EST Thursday 
     for RIZ001>008.
MARINE...Gale Warning from 1 PM this afternoon to 7 PM EST Thursday for 
     ANZ230>237-250-251-254>256.

&&

$$
SYNOPSIS...KJC/RM
NEAR TERM...Frank
SHORT TERM...KJC
LONG TERM...RM
AVIATION...Frank/KJC
MARINE...KJC/RM