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Area forecast discussion 
National Weather Service Taunton Massachusetts
131 am EDT Friday may 29 2015

any leftover showers will come to an end this evening as the cold
front slows down near the South Coast overnight. On Friday...high
pressure will bring dry conditions. Another cold front will slowly
move across the region this weekend...bringing a greater chance
for showers and some scattered thunderstorms. This front may
linger near our area into the beginning of the next week...with
high pressure returning by midweek.


Near term /until 6 am this morning/...

200 am update...

Cold front is now situated across ksnc through kpvd into kpvc.
This front is still slow going and will eventually become washed
out overnight. Ahead of the front significant pooling of moisture
has allowed for fog and low clouds to develop across the South
Coast...cape and islands. Visibilities will drop between 2-5 miles...low
confidence on dense fog.

Otherwise dry air continues to filter in across the region as
dewpoints continue to drop into the middle to low 50s. Where rain
occurred...and dry air moving in aloft could see some fog develop
across valley regions thanks a moist low level inversion.


Short term /6 am this morning through 6 PM Saturday/...
weak ridge of high pressure will gradually crest over the region
through the daylight hours. Winds will be light...but gradually
shifting back to the S...from the northwest through the day. Given the
light winds...expect local sea breezes to limit diurnal temperature
trends near the coastlines. Inland however...with some
downsloping...CT valley locations will make a run at the middle 80s.
Mainly upper 70s elsewhere away from the coast.

Tomorrow night...
although surface high pressure center will be shifting to well S of Nova
Scotia...upper level ridge will continue to build thanks to steady
warm advection upstream. This will keep any activity associated
with another slow moving cold front...well to the west. Expect only
increasing high clouds across the west overnight. The only caveat may
be near S coastal regions...where southerly flow and slight increase in
dewpoints could promote development of some localized marine fog and
stratus once again. This rise in dewpoints will also keep mins up a
bit...mainly dipping into the upper 50s in the coolest spots.


Long term /Saturday night through Thursday/...
overview and model preferences...

Overall upper level ridging along eastern Seaboard appears to
break down Saturday...then trough out of central Canada begins to
shift east late this weekend into early next week. Associated cold
front will be slow to clear the region as it runs parallel to the
upper flow. Timing issues come in play from Monday Onward...
depending upon how far S the front finally settles while high
pressure builds out of southern Ontario and the Great Lakes eastward.

Leaned toward the available guidance early in this period then
transitioned over the gefs and ecens guidance which showed a bit
better continuity.


Saturday...high pressure off the eastern Seaboard pushes further
offshore during this timeframe...with good SW wind flow and
increasing humidity moving NE into the region. Models tending to
slow the progress of the approaching front out of western Quebec
as the upper ridge slowly breaks down and shifts east. Have mention
of chance probability of precipitation moving into western areas during Sat afternoon...
then should push slowly southeast Sat night.

Good instability with this front as k indices increase to the
Lower-Middle 30s. Have mentioned chance probability of precipitation...but mentioned only
slight chance of thunderstorms Sat night. Noting increasing precipitable waters
along and ahead of this front as well...up to 1.7 inches during
Sat night so could see some locally heavy downpours with any
activity. Will see high temperatures reach around 80 inland...but only in
the upper 60s to lower 70s along the immediate S coast. May see
SW winds gusting up to around 25-30 miles per hour across Rhode Island/southeast Massachusetts Sat

Sunday...looks like best shot of moisture moves across the
region sun/Sun night. Carrying Cat probability of precipitation near/along the slowly
moving well as some scattered thunderstorms. Precipitable waters increase
to 1.7 to 1.8 could also see some heavy downpours.
At this point...think the front will push near or S of the Mass
Pike around Sun night...but will tend to slow down across southern
areas overnight. This will lower the chance for thunderstorms as
more stable air moves into north Massachusetts Sun night...but still could see
spotty convection across north CT/RI/se Massachusetts. Have kept likely probability of precipitation
going through around 06z...then slowly lower across central and
northern areas after that. Precipitation looks to taper off across the
Route 2 area by around sunrise Monday...but timing is still in

Monday...a lot of uncertainty continues as moving the front across
the region...with timing differences amongst the model suite.
Looks like the chance for precipitation lingers through Monday and even into
Monday night...with the best chance across north CT/RI/se Massachusetts. Winds do
start to shift around to north-NE across central and north Massachusetts so this will
cut back on thunderstorm activity as cooler air moves in. For
now...tend to taper off precipitation by Monday night across most
areas...but do linger it along the S coast through at least
midnight Monday night. It will be much cooler with highs only in the
60s...and may not even break 60 along the East Coast with onshore

Tuesday-Wednesday...precipitation should finally push off the S coast by
around midday Tuesday at the latest. NE winds pick up as high pressure
crosses northern New England during this timeframe. Have carried a
dry and seasonable forecast on Wednesday.


Aviation /06z Friday through Tuesday/...
forecaster confidence levels...

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

Before 12z...high confidence. Cold front will sweep through
overnight. Ahead of front could see IFR/MVFR stratus and fog. Also
could see MVFR fog develop across CT valley sites.

Today and tonight...high confidence. Mainly VFR. Expect sea
breezes with winds shifting mainly to the east late in the day. Some
patchy MVFR ceilings could develop along South Coast tonight.

Saturday...moderate confidence. Mainly VFR through the day. MVFR
ceilings could develop within -shra/-tsra across CT valley region.

Kbos terminal...high confidence in taf. Sea breeze will develop
between 13-15z.

Kbdl terminal...high confidence in taf.

Outlook...Sunday through Tuesday...moderate confidence.

Sunday...numerous showers with scattered thunderstorms possible during
the day with local MVFR conditions. Light winds shift to north-NE
during the day...then become NE Sun night which may gust up to
around 20 knots along the S coast. Showers linger Sunday night.

Monday...scattered showers lingering with local MVFR conditions early
but will improve from north-S during the day except along the S coast
where showers will hang in through Sun night. May see brief MVFR
in any showers there Sun night. NE winds gusting to 20-25 across
Outer Cape cod and the islands.

Tuesday...mainly VFR conditions. May see isolated showers early Tuesday
along S coast but should move offshore. NE wind gusts to 25 knots
still possible across the Outer Cape and islands.


forecaster confidence levels...

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

Short term /tonight through Friday night/...

Tonight...high confidence.
Gusty winds overnight have dropped off and seas are below 5ft.
Have dropped the Small Craft Advisory.

Friday and Friday night...high confidence.
High pressure builds over the waters. Mainly quiet boating weather
expected although some stratus/fog is possible mainly on the southern
waters tomorrow night.

Outlook...Saturday through Tuesday...moderate confidence.

Saturday...SW winds will likely gust up to 25 knots across the
eastern outer waters...and possibly on the near shore waters Sat
afternoon. Seas build to around 5 feet on all the outer waters...
possibly into Rhode Island and Block Island sounds. Winds should diminish
during Sat night. Visibility restrictions in patchy fog along S coastal
waters early...then should improve.

Sunday...cold front slowly crosses the waters. May see brief
gusts to 25 knots as front passes during Sunday...then will stall
near or just S of the S coast Sun night. Winds shift to east-NE as
front passes. Areas of showers with scattered thunderstorms. Local visibility

Monday-Tuesday...expect mainly NE winds. Gusts to 25 knots across
the southern open waters as the front slowly moves offshore.
Seas build up to 6-8 feet on the southern outer waters to east of
Cape Cod...and up to 5 feet on the eastern outer waters. May see
lingering showers during Monday across the southern waters.


Box watches/warnings/advisories...
Rhode Island...none.


near term...dunten
short term...doody
long term...evt

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