Area Forecast Discussion
Issued by NWS Boston, MA

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000
FXUS61 KBOX 070002
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
702 PM EST Sat Mar 6 2021

.SYNOPSIS...
Dry weather persists through the middle of next week. Colder than
normal through the weekend, but then a significant warm up will
lead to well above normal temperatures away from the immediate
coast by mid week. A cold front moves through on Friday bringing
our next chance of precipitation.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
7 PM Update...
Not much to report for this update. Few clouds remain this
evening, especially in western zones of MA/CT. Clouds continue
to clear out as drier air moves in overnight. Temperatures range
from the mid-20s to the low-30 ... we are still on track for
temperatures to dip to the single digits across the interior to
the mid-20s at the coast. Otherwise, the forecast remains on
track and you can read the previous forecast below.

------------------------------------------------------------

Highlights

* Dry and quiet weather with cooler than normal temperatures
  tonight.

Cyclonic flow persists through this period over New England. A
ridge axis will build from Manitoba into the Upper Mississippi
River Valley and western Ontario by late tonight. High pressure
will builds into eastern portions of Ontario by late tonight and
nudge into southern New England.

Should see any cloud cover diminishing as the night progresses
as the high nudges in and advects drier air in from the W/WNW.
Have gone with the 25th percentile of guidance as am unsure how
quickly winds will become light. If wind speeds decrease a bit
quicker then may need to lower temperatures further due to
stronger radiational cooling. Lows range from the single digits
above zero across the higher terrain of the interior to the low
20s along the coastal plain.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Highlights

* Dry and quiet weather continues with below normal temperatures
  on Sunday and Sunday night.

Cyclonic flow over eastern Canada into the Mid Atlantic to
start early on Sunday, while a ridge builds over western Ontario
into the Upper Mississippi River Valley. The cyclonic flow
persists through Sunday and Sunday night with a shortwave moving
in late on Sunday into early Monday. The ridge will build into
Quebec by late Sunday night. High pressure builds into the
eastern Great Lakes on Sunday and along much of the East Coast
by late Sunday night.

Sunday and Sunday night...

High pressure continues to relax the pressure gradient as it
builds in. Expecting winds to be light through this period with
the direction remaining out of the NW due to the position of the
high. Below normal temperatures continue with northwesterly
cold air advection through the period. Should see 925 hPa
temperatures between -5 to -10 degrees Celsius. Highs on Sunday
generally in the 30s. Low temperatures bottoming out in the
teens across the interior and low to mid 20s along the coast
Sunday night.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Highlights...

* Significant warm up for the new work week, with the peak of
  warmth on Wednesday and Thursday away from the immediate
  coast.
* Next chance of any meaningful precipitation does not arrive
  until late next week with a cold front.

The new work week looks to feature a transition into a
+AO/+NAO/-PNA regime, which is favorable for a more significant
and extended period of warmth. Not surprisingly, the CPC has 80
percent probability of above normal temperatures for southern
New England. Mid level ridging continues to build over the
Northeast Tuesday into Thursday, which will lead to well above
normal temperatures away from the immediate influence of the
still relatively cold ocean. Colder weather should return late
next week into next weekend as a cold front approaches from the
northwest.

Not seeing many rainfall chances over this portion of the
forecast. While there should be a warm front passing by some
time on Wednesday, the best lift and moisture is expected to be
well to our north. Humidity should increase with the persistent
southwest flow ahead of a cold front, which should mean a risk
for showers late next week. While the precise timing is still
questionable, still favoring this cold front moving offshore
some time late Friday into Friday night.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Forecaster Confidence Levels.

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

Tonight...High confidence

VFR with WNW to NW winds around 5-10 kts, isolated gust up to
20 kts possible across the CT River Valley through 02z-04z. A few
areas of some 5 kft cloud bases late tonight, then becoming clear
for Sunday morning.

Sunday and Sunday Night...High confidence

VFR with NW winds around 5-10 kts.

KBOS TAF...High confidence in TAF.

KBDL TAF...High confidence in TAF.

Outlook /Monday through Thursday/...

Monday: VFR.

Monday Night: Mainly VFR, with local MVFR possible.

Tuesday through Wednesday Night: VFR.

Thursday: VFR. Breezy. Slight chance SHRA.

&&

.MARINE...
Confidence high throughout the forecast period. Winds shift to
the NW tonight and diminishing. Have cancelled the Small Craft
Advisory east of Cape Cod as conditions have already fallen
below criteria. Wind gusts and wave heights along the southern
outer waters remain borderline into this evening, so have kept
the Small Craft Advisory going here.

Winds will diminish as high pressure relaxes the pressure
gradient through Sunday and resultant waves will fall as well.
Winds shifting to the NNW Sunday night into early Monday as high
pressure moves closer to the region. Speeds generally 10-15 kts
or less.

.Outlook /Monday through Thursday/...

Monday through Monday Night: Winds less than 25 kt.

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

Tuesday Night through Wednesday: Winds less than 25 kt.

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

Thursday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Seas up to 5 ft.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 9 PM EST this evening for ANZ255-
     256.

&&

$$
SYNOPSIS...Belk/BL
NEAR TERM...BL/Gaucher
SHORT TERM...BL
LONG TERM...Belk
AVIATION...Belk/BL/Gaucher
MARINE...Belk/BL


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