Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Taunton Massachusetts
915 PM EDT Wednesday Mar 12 2014
an intensifying low pressure will cross southern New England late
this evening and overnight. Rain will transition to snow as this
low pressure moves by. Temperatures plummet tonight...allowing for
a flash freeze. Bitterly cold air and strong winds expected
Thursday with lingering snow showers taper off during the
afternoon. Milder weather returns Friday and Sat...before colder air
returns Sunday into early next week.
Near term /until 6 am Thursday morning/...
***flash freeze overnight with wet roads/walkways quickly becoming
915 PM update...
Strong low pressure just to our west will rapidly move east across
Rhode Island/southeast Massachusetts over the next few hours. Currently...warm
advection aloft was allowing for numerous rain showers.
Temperatures were still above freezing as of middle evening...but this
will quickly be changing. As low pressure moves east of the
region...temperatures will crash on gusty north to northwest
winds. In fact...temperatures currently in the lower to middle 50s
across Rhode Island/southeast Massachusetts may be in the upper teens by
Thursday morning. This is an extremely impressive temperature drop
for southern New England standards.
The cold air initially comes in shallow...so the rain may
transition to a brief period of freezing rain/sleet especially to
the north of the Massachusetts Turnpike. May even see a brief period of
freezing rain in Boston...which is quite unusual. The ptype will
then transition over to snow as colder air works in from the
Given the fact that the middle level centers are tracking to our
northwest...the heavy snow will be confined to northern New England.
Most of the region will just see an inch or two of snow...with a bit
more across southern New Hampshire/northwest Massachusetts.
The main concern is not snow amounts...but a rapid freeze up of
wet roads as temperatures plummet. This has the potential to be one
of the more significant flash freezes we have seen in southern New
England. Roads and walkways may become very treacherous...with icy
conditions persisting into the Thursday morning commute.
We have issued a Special Weather Statement to highlight the concern
about the flash freeze. Light snow may persist though into much
of Thursday morning as well given a pretty potent upper level shortwave
moving across the region.
Low temperatures by 12z Thursday will be in the teens to lower 20s. Gusty
northwest winds will result in wind chill values will range from 10
below zero to 10 above zero by daybreak!
Long term /Thursday night through Wednesday/...
12/12z models are in good agreement through the long term. There
are some discrepancies out towards the end of the period but overall
the synoptic pattern both aloft and at the surface is in good
agreement. There are basically two potential periods of
precipitation in the long term. One late Friday night into Saturday
morning and the other is Tuesday night into Wednesday next week.
Both associated with low pressure moving through Quebec pulling a
cold front through southern New England. Aside from these two
periods of precipitation...looking at dry weather with below normal
Friday...low pressure moves through the Great Lakes into southern
Quebec. Weather should be quiet for much of the day though expect
increasing clouds Friday night ahead of a cold front.
Saturday and Sunday...could see a period of mixed precipitation
ahead of the cold front beginning early Saturday morning...mainly
across the northwest interior portion of the area. This will be
short lived and come to an end as the front sweeps across southern
New England by midday Saturday. High temperatures will actually be
slightly above normal...reaching into the upper 40s to around 50.
Despite the precipitation...Saturday will be the pick of the weekend
in terms of temperatures as colder air moves in Saturday night.
Highs Sunday are expected to be in the 30s to middle 40s as high
pressure builds into southern New England.
Monday...temperatures just below normal will continue as high
pressure crests over the region.
Tuesday and Wednesday...another low pressure center will move
through the Great Lakes into southern Quebec bringing another chance
of precipitation /currently looking like snow Tuesday night
transitioning to rain Wednesday/ to the region. Precipitation will
come to an end late Wednesday as the cold front moves through
southern New England. Temperatures remain below normal for middle
Aviation /01z Thursday through Monday/...
low...less than 30 percent.
Moderate...30 to 60 percent.
High...greater than 60 percent.
Short term...through Thursday night.
High confidence in trends...lower confidence in exact timing.
Tonight...mainly IFR with some MVFR conditions. Rain transitions
to snow from northwest to southeast as the night wears on. A brief
period of sleet/freezing rain is possible during the transition
especially north of the Massachusetts Turnpike. Northerly winds will gust
between 20 and 30 knots behind the storm by late evening into the
overnight hours. Some low level wind shear possible as winds shift to the northwest
Thursday...MVFR to IFR conditions in snow showers in the morning
should improve some during the afternoon from west to east.
Expecting conditions to improve to MVFR...if not VFR...by middle to
late afternoon. Northwest wind gusts of 30 to 45 knots expected.
Thursday night...high confidence VFR.
Preliminary snowfall forecast...
Bos...1 to 2 inches tonight/Thursday am
pvd...1/2 to 2 inches tonight/Thursday am
bdl...1/2 to 2 inches tonight/Thursday am
orh...1-3 inches late tonight/Thursday am
mht...2-5 inches late tonight/Thursday am
Kbos terminal...high confidence in trends...moderate confidence in
Kbdl terminal...high confidence in trends...moderate confidence in
Outlook...Friday through Monday.
Friday...high confidence. VFR.
Friday night into Saturday morning...moderate confidence.
Conditions deteriorate to MVFR/IFR in a wintry mix of precipitation across
the northwest interior.
Saturday afternoon through Monday...high confidence. VFR.
forecaster confidence levels...
Low...less than 30 percent.
Moderate...30 to 60 percent.
High...greater than 60 percent.
Short term /tonight through Thursday/...high confidence.
Mixed wind across the waters this afternoon and evening with a
boundary extending east from near Marshfield Massachusetts across the
southern extent of stellwagen bank. East to north winds north of
this boundary...with strong south winds south of this boundary.
Gale force wind gusts are expected as a developing low pressure
moves east along this boundary overnight. Lower visibilities in rain and
snow expected. Moderate freezing spray will develop during
Thursday afternoon into Thursday night as an usually cold air mass
for middle March advances over the waters. Later shifts will likely
need to issue a freezing spray advisory. In addition...seas across
the eastern Atlantic waters will build to between 7 and 13 feet
for Thursday. Winds and seas diminish Thursday night.
Outlook...Friday through Monday...
Friday through Saturday...high confidence. Small craft advisories
likely needed with southwesterly winds gusting to 30 kts ahead of a
cold front moving over the waters. Seas increase to 5 to 7 feet on
the outer waters.
Saturday night...high confidence. Winds shift to the northwest and
winds and seas gradually diminish behind the cold front.
Sunday...moderate confidence. Winds and seas should remain below
small craft criteria for most of the period as high pressure builds
over the waters.
Monday...moderate confidence. Winds and seas increase to just over
small craft criteria on the outer waters.
near record cold possible Thursday night into early Friday. Here are
record low temperatures for Friday March 14th...
Bradley Airport... low...9
CT...Winter Weather Advisory until noon EDT Thursday for ctz002>004.
Massachusetts...Winter Weather Advisory until noon EDT Thursday for maz002-003.
Winter Weather Advisory until noon EDT Thursday for maz004>019-
New Hampshire...Winter Weather Advisory until noon EDT Thursday for nhz011-012-
Rhode Island...Winter Weather Advisory until noon EDT Thursday for riz001>005.
Marine...Gale Warning from 8 am to 8 PM EDT Thursday for anz232>235-237-
Gale Warning from 5 am to 8 PM EDT Thursday for anz230-236.
Gale Warning from 2 am to 8 PM EDT Thursday for anz231-250-251.