Area forecast discussion
National Weather Service Taunton Massachusetts
342 am EDT Wednesday Jun 19 2013
Synopsis...
High pressure builds from the Great Lakes into the northeast
today...bringing southern New England a period of dry and near
seasonable temperatures through Thursday. The high moves offshore
Friday and begins a trend toward warmer and more humid weather
into this weekend and next week. Mainly dry weather will prevail
during this time but can/T rule out a few diurnal
showers/thunderstorms.
&&
Near term /until 6 PM this evening/...
4 am update...
Showers coming to an end as the broad trough disturbance pushes
east across New England behind which subsidence and drier air
dominate. Chance to slight chance probability of precipitation continue mainly for the
cape and islands towards sunrise. Rainfall amounts will be very
light...no flooding anticipated. Any patchy dense fog should begin
to burn off with sunrise.
Today...
Clouds and isolated showers will linger along the southeast
shoreline of southern New England during the early morning
hours...pushing offshore towards midday. Will keep chance to
slight chance probability of precipitation accordingly.
In wake of the broad frontal disturbance high pressure and a low-
to middle-level cooler airmass /h85 temperatures around +7c/ builds in from
the north and west. Anticipating boundary layer mixing up to
around 4-6 kft. Should see the mix-down of faster momentum and
drier air...while supporting the development of scattered to
broken fair-weather cumulus /followed through with a 50-50 blend
of bias-corrected MOS guidance for dewpoints along with forecasted
mix-down of drier air/. Fastest of winds will be across eastern
New England collocated with the tighter pressure gradient early in
the day... relaxing into evening. Highs around the low to middle
70s...a few local spots warming into the upper 70s.
&&
Short term /6 PM this evening through 6 PM Thursday/...
Tonight...
High pressure in control. Light and variable winds under mostly
clear conditions. Anticipating effective radiational cooling.
Will go lower than MOS guidance by several degrees...noting the
colder spots climatologically of the higher elevations...southeast
coastal plain...and Marthas Vineyard. Could get close to record
minimum temperatures as lows are forecasted around the middle 40s.
Thursday...
High pressure remains in control. Will see light and variable
winds begin to veer out of the south. Broad scale subsidence
should limit the development of fair-weather cumulus. Looking to
be a mostly clear day. Highs around the middle- to upper-70s. Could
see a few spots warm to values around 80 degrees.
&&
Long term /Thursday night through Tuesday/...
Highlights...
* trend toward warmer and more humid weather especially early next weak
* wet Jun pattern will give way to a drier more typical Summer
type regime...a few diurnal showers/thunderstorms each day
Both deterministic and ensemble guidance are in good agreement on
deamplifying the upper air pattern this period and transition to a
more typical Summer pattern with a subtropical ridge developing
across the southern states into the middle Atlantic region. This will
displace the polar jet farther north across the northern tier states
into southern Canada. This will support warmer more humid air
inching northward toward southern New England. So the overall trend
this period will be for warmer temperatures and higher humidity.
As for precipitation...given the proximity of the polar jet and associated
frontal boundary to southern New England...can/T rule out a few
diurnal showers/thunderstorms Friday and Sat...typical Summer type pattern.
Better chance of showers/thunderstorms may come sun/Monday as warm front moves
across the area as true warm sector airmass makes a push toward
southern New England early next week.
&&
Aviation /07z Wednesday through Sunday/...
Forecaster confidence levels...
Low...less than 30 percent.
Moderate...30 to 60 percent.
High...greater than 60 percent.
Near term /through Thursday/...moderate confidence.
Confidence in trends of ceilings and visibilities improving...but difficult
to be more specific concerning timing. Expect gradual improvement
northwest to southeast...MVFR-IFR ceilings lifting VFR...visibilities improving into
morning and as late as midday. Otherwise may see some gusty
northerly winds across eastern New England...prevailing VFR with
scattered-broken cumulus around 4-6 kft. Winds become light and variable
overnight. May need to be concerned about patchy dense fog in
Interior Valley locales. But anticipating VFR continuing into
Thursday with light and variable flow veering out of the south.
Kbos terminal...moderate confidence. Sea-breeze possible around
the midday hours.
Kbdl terminal...moderate confidence.
Outlook...Thursday night through Sunday...
Outlook...Thursday night through Sunday...
VFR along with dry weather Thursday night through Friday night. Sat and beyond...
low probability of diurnal showers and thunderstorms briefly
lowering conditions to MVFR/IFR.
&&
Marine...
Forecaster confidence levels...
Low...less than 30 percent.
Moderate...30 to 60 percent.
High...greater than 60 percent.
Near term /through Thursday/...moderate confidence.
With a cold front sliding across and east of the waters along with
shower activity...and high pressure building out of the west...
will see an increase of northerly winds with potential gusts up to
25 kts resulting in fetch across the waters amplifying waves
heights up to around 5 feet over the south-southeast outer waters.
Winds and waves should dissipate tonight into Thursday as high
pressure builds over the waters with light and variable winds.
Outlook...Thursday night through Sunday...
High confidence.
Quiet boating weather expected through Sunday with high pressure
near or over the waters. The only exception is Saturday and/or
Sunday when showers and thunderstorms may limit visibilities on the
waters.
&&
Hydrology...
Concerning river flooding...the Charles at Dover remains just
above flood stage. Latest guidance indicates that this river will
only slowly fall and remain in minor flood through late Thursday
night.
&&
Climate...
A period of effective nocturnal cooling will be possible overnight
Wednesday into Thursday morning. Consequentially...lows could
reach record minimum temperatures. Here is a listing of record low
temperatures for June 20th:
Boston... 47 in 1918
Hartford... 45 in 1918
Providence... 45 in 1918
Worcester... 37 in 1926
&&
Box watches/warnings/advisories...
CT...none.
Massachusetts...none.
New Hampshire...none.
Rhode Island...none.
Marine...Small Craft Advisory from 6 am this morning to noon EDT today
for anz232-234.
Small Craft Advisory until 6 PM EDT this evening for
anz254>256.
&&
$$
Synopsis...nocera/sipprell
near term...sipprell
short term...sipprell
long term...nocera
aviation...nocera/sipprell
marine...nocera/sipprell
hydrology...sipprell
climate...sipprell
