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Area forecast discussion 
National Weather Service Taunton Massachusetts
1036 am EDT Wednesday Apr 1 2015

Synopsis...

Dry but chillier weather moves through today...followed by warming
on Thursday. A few waves of low pressure ahead of a slow moving
cold front will bring periods of showers late Thursday night into
Saturday morning with mild temperatures. Dry and chillier weather
follows later Saturday into Saturday night. Fast moving low
pressure may bring a few rain and/or snow showers to the region
Sunday into Sunday night. Periods of unsettled weather possible
for the first half of next week...but confidence is quite low.

&&

Near term /until 6 PM this evening/...

10 am update ... no major changes.

Mostly clear skies and plenty of sunshine expected as high pressure
moves in from the west. Increasing early April sun angle will allow
highs to recover well into the 40s for much of the region...despite
850 temperatures between -6c and -8c. Breezy early with northwest wind gusts of
20 miles per hour at times...although stronger gusts of 25 to 30 miles per hour are
expected across the cape/islands.

&&

Short term /6 PM this evening through 6 PM Thursday/...

Tonight...
dry weather prevails most of the night as high pressure crests over the
region. The combination of this dry air...and mass fields
suggesting weak pressure gradient...and feel we have a good setup for
radiational cooling early. Will likely see a few middle-high clouds
spill over from the west late which will slow the process...but given
the potential...will likely see temperatures fall back into the 20s
across much of the region in spite of the increasing clouds late.

Tomorrow...
warm front will be sliding mainly north of the region...but the nose
of attendant low level jet and middle level moisture will sliding across the northern
tier of southern New England. Although there is some middle level moisture
and light overruning lift to work with...it will be entering a
generally dry airmass with high pressure and subsidence just offshore.
Therefore...will continue with mainly dry probability of precipitation. However...not out
of the question some daytime showers are noted especially across
the north. Otherwise...strong SW pressure gradient will lead to gusts
25-35 miles per hour at times. This will mitigate East Coast sea breezes but
likely enhance S coastal sea breezes. Therefore...with 850 mb temperatures
warming as the front moves through will see high temperatures shift above
normal in spite of the clouds. Mainly middle 50s.

&&

Long term /Thursday night through Tuesday/...

Highlights...

* mild Thursday night/Friday and possibly into part of Sat
* periods of showers Thursday night into Sat am but not a total washout
* much cooler sun/Sun night with even a few rain/snow showers poss.
* Unsettled weather possible at times for first half of next week

Details...

Thursday night and Friday...

An approaching shortwave will result in a burst of instability/middle
level lift late Thursday night into Friday am. Scattered showers are
expected and we can/T rule out a few embedded thunderstorms with
marginal elevated instability. Precipitable waters 1 to 2 Standard deviations
above normal may result in some brief localized heavy rainfall...but
no significant flooding problems are expected. Precipitation will
be showery so not expecting the entire period to be a washout. May
even see a lull in the activity later Friday am into the afternoon
north of the Massachusetts Pike...as drier air briefly works into the region.

Low temperatures Thursday night will only fall into the 40s...but may see some
areas already above 50 by daybreak Friday with strong southwest low
level jet/warm advection developing. Inversion will keep strongest
winds off the deck...but some southwest wind gusts of 25 to 35 miles per hour
are possible especially in heavier showers. High temperatures on Friday
are tricky and will depend on if we can muster any breaks in the
cloud cover. Think there is a pretty good chance much of the area
breaks 60. Low risk some locations reach between 65 and 70 if more
sunshine occurs then currently expected.

Friday night in Saturday...

Second and stronger area of low pressure will move along a cold
front that will be sagging to our south Friday night and Sat am. The
models disagree on the track with the GFS tracking the system across
the far southeast New England coast...while the European model (ecmwf) brings it
furthest northwest into interior southern New England. Either way
should see a decent period of rain sometime Friday night into Sat am.
There is a low risk rain could end as a bit of wet snow Sat
am...mainly in the higher terrain. The GFS is most aggressive in
this scenario even showing the risk for a few inches in the high
terrain...but it is a cold outlier so a low probability at this
point.

Saturday night and Sunday...

Chillier air works back into the region later Saturday and into
Saturday night. A wave of low pressure may approach from the west
Sunday and/or Sunday night. Right now the models have the system
tracking near or just north of our region...keeping the bulk of the
precipitation to our north...so would just expect a few rain or snow
showers in southern New England. However...track very uncertain in
this time range so if it shifts south it will increase our chances
in a period of steady rain or even wet snow based on colder thermal
profiles.

Monday into Wednesday of next week...

Forecast confidence is quite low. A Battle Ground will setup with
very cold air to our north across eastern Canada and much milder air
to our south...as low pressure approaches from the west. The 00z
GFS/ggem have the initial low pressure system tracking to our west
eventually putting US on the mild/showery side of the system.
Meanwhile...the 00z European model (ecmwf) and even a few of the gefs ensembles are
much further south resulting in a cold rain and even some
accumulating wet snow. Whether or not its cold enough for any snow
remains to be seen. Probably smart to lean on the cooler side with
temperatures given time of year and high pressure to the north.

&&

Aviation /15z Wednesday through Sunday/...

Forecaster confidence levels...

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

Short term /through Thursday/...high confidence.

Today and tonight...
VFR. Scattered middle-level cloud. North/northwest wind gusts 15-20 knots through early
afternoon today...25 to perhaps near 30 knot gusts for a time
across the cape/Nantucket. Winds diminish thereafter.

Thursday...
VFR. More clouds expected and maybe an isolated shower in the west.
Winds shift to the SW.

Kbos taf...high confidence in taf.

Kbdl taf...high confidence in taf.

Outlook...Thursday night through Sunday...

Thursday night through Saturday am...moderate confidence. Mainly
MVFR conditions with even some IFR ceilings/visibilities possible at times.
Periods of showers with even a few isolated thunderstorms possible
late Thursday night into Friday am. Also...low level wind shear expected with southwest
winds of 60 to 70 knots between 2 and 3 thousand feet late Thursday night
into Friday am.

Saturday afternoon into Sunday...moderate confidence. Mainly VFR
conditions but a period of MVFR-IFR conditions are possible sometime
Sunday and/or Sunday night in a few rain/snow showers.

&&

Marine...

Forecaster confidence levels...

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

Short term /through Thursday/...high confidence.

10 am update ... no major changes.

Today into tonight...
high pressure moving in from the west will lead to gusty northwest winds around
25 knots. Wind driven seas of 5-6 feet. Small craft advisories will
continue through this morning/early afternoon. Lighter winds
tonight with a period of quiet boating weather expected.

Thursday...
winds shift to the SW and increase by Thursday afternoon. Gusts to
around 20 knots on the ocean waters...but may reach 25-30 knots near
shore. Expect gradually building swell as well. Small Craft
Advisory may be needed for the afternoon/evening timeframe.

Outlook...Thursday night through Sunday...

Thursday night and Friday...moderate confidence. South to southwest
wind gusts of 20 to 30 knots expected Thursday night into Friday am with
strong low level jet. Low risk of some brief marginal gale force
wind gusts in heavier showers/isolated thunderstorms...but given
inversion will not hoist a gale watch.

Saturday and Sunday...moderate confidence. Strong northwest Small Craft Advisory wind
gusts expected in the cold air advection pattern behind a cold front
Sat afternoon into Sunday. Even a period of marginal gale force
wind later Sat into Sat night in the strong cold air advection
pattern.

&&

Box watches/warnings/advisories...

CT...none.
Massachusetts...none.
Rhode Island...none.
Marine...Small Craft Advisory until 2 PM EDT this afternoon for
anz231>234-251-256.
Small Craft Advisory until noon EDT today for anz235-237.
Small Craft Advisory until 6 PM EDT this evening for anz250.
Small Craft Advisory until 2 am EDT Thursday for anz254-255.

&&

$$

Synopsis...Frank/doody
near term...Frank/doody/sipprell
short term...doody
long term...Frank
aviation...Frank/doody/sipprell
marine...Frank/doody

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