Area forecast discussion
National Weather Service Taunton Massachusetts
1009 am EDT Sat may 25 2013
Synopsis...
a low pressure just off the coast will slowly move north through
tonight. Some improvement is likely Sunday as this low departs
into northern New England. Mainly dry weather is anticipated with
moderating temperatures Monday into Tuesday. A warm front will move
through Wednesday bringing some showers and thunder. Expect warm
and muggy conditions by the end of the work week.
&&
Near term /until 6 PM this evening/...
10 am update...forecast is on track for today for the most part.
Made some minor updates to the pop/weather grids for the latest precipitation
trends...but otherwise the forecast was in good shape. Latest
msas analysis puts the low pressure into the Gulf of Maine as of 9
am. Continue to see a good swath of dry air on the water vapor
imagery east of the Connecticut valley. This may allow for some
breaks in the clouds across the cape and islands as well as Cape
Ann. However...think low level moisture is substantial enough that
drizzle and showers will continue for much of the rest of the
area. Steadier rain across the east slopes of the Berks and
western Connecticut is nearly stationary at this time.
Previous discussion...
25/00z models have come into very good agreement with their
handling of the synoptic features. As such...used a general model
compromise to handle the timing.
Overall...expecting a low pressure over Massachusetts Bay to stay
nearly stationary today. This will generate periods of showers
across southern New England...as well as maintaining decent cold
air advection. High temperatures today are not expected to be much
higher than our normal low temperatures. For some higher
locations...high temperatures today may actually be lower than the
normal low temperature.
Heights aloft continue to fall which results in cooling from the
top down. Very impressive synoptic scale forcing via middle level
q-vector convergence. Strongest lift will once again be across
western sections of CT/Massachusetts into southwest New Hampshire...centered around the
I-91 corridor. Model soundings suggest late in the day across
this area especially the higher terrain of Massachusetts/New Hampshire that rain may mix
or change to snow at times when precipitation intensity is
greatest. This will be most common at elevations greater than 1000
feet as freezing levels drop to this level. Surface and ground
temperatures likely too warm for any accumulation but minor snow
accumulation possible on trees/power lines. Don/T expect any
impact just some decorative snow possible higher terrain.
&&
Short term /6 PM this evening through 6 PM Sunday/...
a middle-level low will move slightly northeast today...which will
place southern New England well into the core of colder air aloft
overnight. This will continue the possibility for mixed rain/snow
showers across the higher terrain. Low temperatures are expected
to be 10 to 15 degrees below seasonal normals.
As for any convection...have removed mention for now but would not
be surprised to hear a few isolated rumbles as precipitation and upper level
system start to shift NE.
On Sunday...leftover showers will end from S-north during the day.
Clouds will remain for most of the day as northwest winds pick
up. Expecting gusts up to 30-35 miles per hour...especially across central
and western areas. Will remain cool with highs again 10-15 degrees
below normal.
&&
Long term /Sunday night through Friday/...
highlights...
* improvements on Monday with moderating temperatures through the middle week.
* Warm front middle-week will bring around of showers and thunder.
* Muggy and well above average conditions return by Thursday.
Confidence level/model guidance...
High confidence in precipitation forecast...moderate confidence on
exact timing. Due to uncertainty in amplification of the ridge by
end of next week...have moderate confidence on temperatures. Models are in
fairly good agreement with this run showing a upper-level trough
pushing into the western Continental U.S....while a strong amplified ridge
moves over the eastern USA. Models are struggling with how much The
Heights build by the end of next week. Therefore have leaned with
wpc thinking for the forecast and the ensemble means for days 6 and
7.
Details...
Monday and Tuesday...upper level trough will eject eastward as a
ridge builds over the Midwest. The surface low which brought rain
and cool temperatures will be well in the Gulf of Maine allowing for
drying conditions and sunny skies. Am concerned about Sun night
temperatures...may be to warm as winds decrease and skies clear...frost
may be a possibility especially in the northwest zones. Otherwise expect a
pleasant Memorial Day with temperatures reaching into the low to middle 70s
and sunny skies. Tuesday will be a repeat but with temperatures warming
into the middle 70s thanks to a more southerly wind component. Cooler
along the coast as sea breezes develop.
Wednesday...upper level ridge will Glide eastward on
Wednesday...however a few ripples in the flow will push a warm
front over New England. Expect showers to develop by Wednesday and
lasting into early Thursday morning. Convection parameters point
to thunderstorm develop along the front so continued the
mentioning of thunder. Temperatures will reach the middle to upper 70s.
Thursday into Friday...
once the warm front pushes through warm and muggy conditions
return to southern New England. Cannot rule out a spot showers
since the region will be in the warm sector. However main issue to
watch is the maximum temperatures...which may reach the middle 80s. Some models
even push the region into the 90s. Since this is several days away
will continue to be modest and keep temperatures into the middle to low 80s.
&&
Aviation /14z Saturday through Wednesday/...
forecaster confidence levels...
Low...less than 30 percent.
Moderate...30 to 60 percent.
High...greater than 60 percent.
Overview...moderate confidence into tonight.
Today...widespread showers over western New England pivots into
eastern New England during the afternoon. Snow may mix in with the
rain across the higher terrain of western Massachusetts and southwest New Hampshire. Northwest
winds may gusts to 25 knots. IFR confined to southeast Massachusetts with MVFR
elsewhere. Timing of precipitation...and the decrease of
visibility...very difficult to time exactly. Tafs were more of an
overall expectation of conditions within showers. Visibility
should be better outside of showers.
Tonight-Sunday...moderate confidence. Unsettled pattern with
variable conditions from VFR to MVFR-IFR conditions in shra/fog.
Low probability of isolated thunderstorm tonight. Precipitation tapers off from S-north
during Sunday with general VFR conditions by late Sunday.
Kbos terminal...moderate confidence in taf. Low confidence in
overall timing.
Kbdl terminal...moderate confidence in taf.
Outlook...Sunday night through Wednesday...
Monday into Tuesday...high confidence. VFR. Moderate confidence on
sea breeze development.
Wednesday...moderated confidence. Mainly VFR. May see clouds/scattered
showers move in ahead of warm front with local MVFR conditions.
&&
Marine...
forecaster confidence levels...
Low...less than 30 percent.
Moderate...30 to 60 percent.
High...greater than 60 percent.
Today...low pressure tracks from Nantucket to Gulf of Maine. Northwest winds
up to 25 knots possible along with lingering S swells south waters of
Rhode Island and Massachusetts. Showers reduce visibility as well. Decided to upgrade some of
the small advisories to gale warnings for this afternoon into this
evening. Held off on a Small Craft Advisory for Cape Cod Bay...as
confidence is not yet high enough to warrant one. Would not be
overly surprised of one is issued later today.
Tonight-Sunday...surface low will linger across the eastern
waters tonight...then shift slowly NE Sunday. Seas remaining
above 5 feet. West-northwest winds will pick up...with gusts up to gale force
mainly across the southern waters to S and east of Nantucket. Winds
should diminish during Sunday afternoon.
Outlook...Sunday night through Wednesday...
Monday and Tuesday...high confidence. Seas will slowly diminish. Wind
gusts on Monday may reach close to 25kts especially across the southern
waters. Otherwise good boating weather on Tuesday.
Wednesday...moderate confidence. Southerly winds will pick up
during the day with gusts up to 20-25 knots. Seas will be above 5 feet.
A Small Craft Advisory may be needed.
&&
Hydrology...
while there may be periodic heavier rain showers across southern
New England today into early Sunday...not thinking it will be
persistent enough to result in flooding. Will have to monitor the
possibility of training cells though. No headlines planned at this
time.
&&
Tides/coastal flooding...
East Coast of Massachusetts this weekend...
High astronomical tides this weekend. At Boston...a high tide of
12.2 feet early Sunday morning at 12:12 am. Estofs indicating up to
0.7 feet surge which seems reasonable. Despite the lack of much
wave action could see some splashover at the typically prone
locations of eastern Massachusetts. Confidence not high enough to issue a
coastal Flood Advisory especially given a marginal event. Later
shifts will have to reevaluate this risk.
&&
Box watches/warnings/advisories...
CT...none.
Massachusetts...none.
New Hampshire...none.
Rhode Island...none.
Marine...Small Craft Advisory from 2 PM this afternoon to 6 PM EDT
Sunday for anz232>234-236.
Small Craft Advisory from 8 PM this evening to noon EDT Sunday
for anz230.
Small Craft Advisory until noon EDT Sunday for anz231-250-251.
Gale Warning from 2 PM this afternoon to 7 am EDT Sunday for
anz235-237.
Gale Warning from midnight tonight to noon EDT Sunday for
anz254.
Gale Warning from 2 PM this afternoon to noon EDT Sunday for
anz255-256.
&&
$$
Synopsis...Belk/dunten
near term...Belk/dunten/rlg
short term...Belk
long term...dunten
aviation...Belk/dunten
marine...Belk/dunten
hydrology...Belk
tides/coastal flooding...Thompson
