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Area forecast discussion 
National Weather Service Taunton Massachusetts
411 PM EDT Sat Aug 1 2015

Synopsis...
seasonably warm this weekend with a risk of scattered showers and
thunderstorms through this afternoon. Warm conditions will
continue into early next week with the threat of showers and
thunderstorms Monday evening into Tuesday. Pattern change by middle-week
will result in temperatures trending a bit below normal late in
the week into the weekend.

&&

Near term /until 6 am Sunday morning/...
through this afternoon...showers are slowly diminishing as they
move eastward across southern New England. These are moving toward
an area of less instability so they should continue to diminish as
they approach the East Coast.

Tonight...any lingering showers will come to an end as diurnal
heating diminishes. Temperatures overnight will be pleasant with
dry air in place over the region. Low temperatures likely to be in the
upper 50s in northwest mass to upper 60s along the coast and in
the urban centers.

&&

Short term /6 am Sunday morning through Sunday night/...
Sunday...a beautiful Summer day with mostly sunny skies and
temperatures in the 80s. No showers or thunderstorms expected with
shortwave ridging overhead.

Sunday night...southwesterly winds will bring higher dewpoints into
the region. This will keep overnight temperatures from falling
much. Expect lows to be in the middle to upper 60s most locations. A
few locations in northwest mass will be around 60.

&&

Long term /Monday through Saturday/...
highlights...
* showers and thunderstorms possible Monday evening into Tuesday
* pattern change brings below normal temperatures late week and next weekend
* threat of showers near the S coast Thursday with more showers possible
Sat

Overview...

Guidance in good agreement on overall pattern in the extended period
featuring closed low over James Bay region gradually moving east
with broad trough setting up over Great Lakes and NE. SW flow aloft and
warm temperatures will prevail into early next week with threat of
showers/tstms. Models begin to diverge later in the period on
handling of individual shortwaves rotating through the flow. Used a
blend of ensemble mean solutions due to uncertainty. A southern
stream wave may clip S coast with some showers Thursday...then another
wave may affect the region next Sat but confidence in the track of
this wave is quite low. Temperatures trending slightly below normal toward
the end of the week into next weekend.

Dailies...

Monday...
fairly potent shortwave moves through the Great Lakes with cold front
moving east of the lakes into New York state by days end. Favorable middle
level lapse rates with promote decent instability during the
day...but main forcing...stronger shear and better moisture will be
confined to the west closer to the front. Models in agreement that
most of Monday may end up dry with main activity remaining to the
west. Have just low chance probability of precipitation for far west new eng for the afternoon.
850 mb temperatures near 17c will result in maximum temperatures around 90 degrees in
the interior valleys...but gusty SW winds will keep temperatures in the 80s
in the coastal plain. It will be humid with dewpoints in the
middle/upper 60s.

Monday night into Tuesday...
cold front moves into southern New England during Monday night. Decent middle level lapse
rates 6.5-7 c/km will help to maintain sufficient surface instability
with sbcapes 1000+ j/kg during the night to support scattered thunderstorms ahead
of the front. 0-6km shear will be increasing from the west with
values reaching and exceeding 40 knots so there will be threat for a
few strong to severe storms Monday night...especially interior if
instability can be realized during the night.

Cold front gets hung up across southern New England during Tuesday with SW flow aloft.
With middle level shortwave moving into the region...will likely see
additional showers/thunderstorms develop especially central and east new eng
where instability will be greatest ahead of the front. Models
indicate 1000-2000 j/kg with 0-6km shear up to 40 knots in area of best
instability so threat for strong to severe storms will exist
Tuesday...mainly central and east new eng.

Wednesday into Thursday...
looks mostly dry Wednesday as front moves offshore with drier west/northwest flow
and seasonable temperatures in the lower 80s...but cooler higher terrain.
Then Thursday will have to see how close a southern stream wave gets to
southern New England. At this time...it appears bulk of showers will remain to the S with
South Coast having the best chance to see some rain. However...any
northward adjustment would result in a wet day for a good part of
southern New England so this will have to be watched.

Friday into Sat...
looks dry Friday with high pressure returning...then low confidence with
track of next surface low for Sat. GFS further north and wet for Sat while
European model (ecmwf) if further S. Temperatures a bit below normal.

&&

Aviation /20z Saturday through Thursday/...
forecaster confidence levels...

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

This afternoon...high confidence. VFR but isolated to widely
scattered showers and T-storms likely this afternoon and early
evening. One or two storms may contain small hail and gusty
winds...however most if not all of the activity will be sub-
severe.

Tonight...high confidence. VFR with any lingering evening
T-storms rapidly diminishing with sunset.

Sunday and Sunday night...high confidence. VFR/dry weather and
good visibility.

Kbos terminal...high confidence in taf. Widely scattered thunderstorms
should develop across Logan/S airspace this afternoon and early
evening but not enough confidence to reflect in taf at this time.

Kbdl terminal...high confidence in taf. Isolated to widely
scattered thunderstorms possible this afternoon and early evening.

Outlook /Monday through Thursday/...

Monday...patchy IFR stratus and fog early near the coast...otherwise
VFR with gusty SW winds 20-25 knots. Low probability of a thunderstorm late in the day
far west new eng.

Monday night...areas of MVFR/IFR stratus and patchy fog possible along
with scattered showers and thunderstorms.

Tuesday...patchy MVFR/IFR stratus and fog early...otherwise mainly VFR.
A few showers/thunderstorms possible.

Wednesday and Thursday....VFR. Low probability of MVFR in showers near the S coast on
Thursday.

&&

Marine...
forecaster confidence levels...

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

Short-term /through Sunday night/...moderate confidence.

This afternoon into tonight...high confidence. Continued southerly
fetch will keep seas in the 5 to 6 foot range on the southern
waters. Have extended the Small Craft Advisory through the night
for these seas. They should diminish overnight.

Sunday and Sunday night...shortwave ridging will allow winds and
seas to diminish below small craft levels. Quiet boating weather
expected.

Outlook /Monday through Thursday/...moderate confidence.

Monday into Tuesday...increasing prefrontal SW winds approaching 25 knots late
Monday and Monday night and continuing into Tuesday with seas building to 5-7
feet over the outer southern waters. Scattered showers/thunderstorms Monday night into
Tuesday.

Wednesday and Thursday...mainly light winds with subsiding seas. Showers
possible over S coastal waters Thursday.

&&

Box watches/warnings/advisories...
CT...none.
Massachusetts...none.
Rhode Island...none.
Marine...Small Craft Advisory for hazardous seas until 6 am EDT Sunday
for anz235-255-256.

&&

$$
Synopsis...kjc/rlg
near term...rlg
short term...rlg
long term...kjc
aviation...kjc/rlg
marine...kjc/rlg

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