Area Forecast Discussion
Issued by NWS Boston, MA

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FXUS61 KBOX 240202
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
1002 PM EDT Tue Jul 23 2019

.SYNOPSIS...
Another round of showers expected later tonight into early
Wednesday across southeast New England as another low
pressure tracks to the south. Mostly dry, seasonable weather
arrives later Wednesday and persist into the weekend, with a
return to warmer and more humid weather early next week.

&&

.NEAR TERM /UNTIL 5 AM WEDNESDAY MORNING/...

10 pm update...

The last in a series of waves of low pressure will track near
the Benchmark overnight. Given this is significantly further
southeast then our last two waves, the showers will generally
remain southeast of a Boston to Providence line. In fact, the
majority of the steady and mainly light rain will fall across the
Cape/Islands. Bulk of the showers should occur through about 8 am.
No thunder or severe weather will occur given front is well to our
southeast. Overnight low temperatures will mainly be in the lower to
middle 60s.

&&

.SHORT TERM /5 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Wednesday...

Mid level trough remains to the west but deep moisture is moving
out with decent drying developing. So any lingering showers over
the Cape/Islands will exit early followed by increasing sunshine
from west to east through the morning and into the afternoon.
Sunshine will be slow to develop over the Cape/Islands. Temps
will be a few degrees below normal with highs upper 70s to lower
80s, but cooler east coastal MA and Cape/Islands where sea
breezes develop.

Wednesday night...

De-amplifying trough axis and shortwave moves into the region
late Wed night, but column is rather dry. So expecting dry
weather with just some high clouds. Cool night with lows
dropping into the 50s in most locations, except lower 60s in the
urban centers.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Highlights ...

* Dry stretch of weather thru the weekend & possibly early next week
* Seasonably warm & comfortable humidity Thu & Fri
* Gradually warmer and more humid Sat & Sun but tolerable
* Highs upper 80s/lower 90s Mon/Tue and dew pts approaching 70

Thursday ...

Upper trough and cold pool (-14C at 500 mb) overhead along with
cyclonic flow lingering. Thus could be some diurnal clouds but the
column probably too dry for any showers. Overall very pleasant with
seasonable highs of 80-85, 75-80 along/near the coast with afternoon
seabreezes. Dew pts in the 50s so very comfortable.

Friday ...

Cold pool and upper trough offshore with rising heights over the
region. Thus plenty of sunshine and temps a few degs warmer with
highs in the low to mid 80s. 1024 mb high over the region will
promote afternoon seabreezes, so cooler along/near the coast. Very
comfortable with dew pts in the mu50s but lower to to mid 60s along
the coast with seabreezes.

The Weekend ...

Remaining pleasant Sat with 1020+ mb high anchored across southern
New England. Seasonable heat and humidity with highs in the 80s and
dew pts in the 60s. By Sunday slightly warmer and more humid with
ridge axis moving offshore, so highs pushing 85-90 inland and dew
pts climbing into the mu60s.

Next Weekend ...

Northern stream mid level trough and attending cold front enters
Great Lakes with increasing low level WAA into southern New England.
Ensembles and deterministic guidance advecting +17C 850 mb temps
across the region. This combined with SW winds will support highs in
the upper 80s to lower 90s away from the south coast. Also
noticeably more humid with dew pts AOA 70.

&&

.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
Forecaster Confidence Levels...

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

Short Term /through Wednesday night/ ...

Tonight... Moderate confidence.
Mainly VFR but another round of showers overnight across the
Cape/Islands may result in some MVFR conditions. Showers may extend
into RI/SE MA for a time, but duration and areal coverage will be
less.

Wednesday... High confidence.
Areas of MVFR/IFR conditions early over Cape/Islands with a few
lingering showers possible. Otherwise VFR. Coastal sea breezes
developing.

Wednesday night... High confidence. VFR.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Thursday through Saturday/ ... High confidence.

VFR.

&&

.MARINE...
Forecaster Confidence Levels...

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

Short Term /through Wednesday Night/...High confidence.

Gusty N winds have diminished, but SCA will linger across our
southern waters overnight from left over swell.

Light winds this evening, then a period of NE winds up to 20 kt
possible over southern waters late tonight and early Wed as low
pres tracks to the south. Light winds Wed night. Seas
approaching 5 ft over southern outer waters Wed/Wed night.

Outlook /Thursday through Sunday/...High confidence.

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

Thursday Night through Saturday Night: Winds less than 25 kt.

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

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 8 AM EDT Wednesday for ANZ255-
256.
     Small Craft Advisory until 2 AM EDT Wednesday for ANZ235-237-
     254.

&&

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


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