Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Taunton Massachusetts
419 PM EST Sat Feb 13 2016
Dangerously cold wind chills of 20 to 35 below zero into Sunday
morning. A period of accumulating snow is then likely for much of
region especially away from the coast late Monday afternoon and
evening...changing to rain by Tuesday morning. A powerful storm
system will likely track west of New England Tuesday into Tuesday
night bringing heavy rain...strong winds and warm temperatures to
the region. A trend toward drier and colder weather follows on
Wednesday and Thursday. Another weather system will bring snow and
rain toward the end of the week.
Near term /until 6 am Sunday morning/...
* dangerously cold wind chills of 20 to 35 below zero tonight into
* coldest low temperatures since January 2004 appear likely in
Boston and Worcester by early Sunday morning
* several record low temperatures may be recorded across southern
Arctic blast! Evaluating sounding climatologies across the region for
12z February 14th...the expected airmass dropping S over the region
overnight is near or below record minimums at h925-85 going as far
back as 1948 with forecast values of 25 to 30 degrees below zero.
Undoubtedly we will see some of the coldest air in the past decade
with several record low temperatures across S New England likely to
be broken big picture...
Large scale pattern remains ridge west/trough east through the week.
Several shortwaves in this flow move through New England...most
notably on Tuesday...Wednesday night...and Saturday. Model mass
fields remain in general agreement through Wednesday...then diverge
with the GFS being the faster solution.
High pressure over the region Monday morning moves off to the east.
Midwest shortwave with surface reflection approaches during the day.
Moisture fields at all levels increase around midday with weak lift
during the afternoon. We will show increasing probability of precipitation through the
afternoon. Thermal profiles favor snow at the onset except possibly
some rain along the South Coast/islands.
Southwest low level jet increases to 45 to 55 kts Monday night and
generates a fair amount of lift as the warmer air moves over the
colder surface air. This will generate stronger precipitation...but also
change the thermal profile which will change ptype from snow to
rain. We expect surface temperatures to be coldest early at night
and then slowly rise overnight. Lingering questions include how fast
the surface layer will warm above freezing...is our database
forecasting too rapid a warmup? Will there be more freezing rain in
the transition than is currently forecast...especially over western
and central mass? These concerns will need to be monitored.
Tuesday will find the upper jet moving into place with southern New
England under the right entrance region. This will further enhance
lift through the column. Forecast tracks on the surface low take it
through either the Hudson Valley or western CT/mass. This is a path
that would bring warmer temperatures to our area. The strong low
level flow will increase to 60-70 knots by midday which will also
bring in higher precipitable water values...at least 2 Standard
deviations above normal. This will mean periods of rain with quantitative precipitation forecast of
1 to 1.5 inches. Temperatures will warm into the 40s and lower 50s
which will aid in snowmelt. The rain and snowmelt will bring
potential for poor drainage flooding especially where drains are
blocked. The passing surface low will swing a cold front through
the region early Saturday night with winds shifting west and precipitation
diminishing at that time.
A second shortwave aloft will sweep overhead Wednesday and Wednesday
night. This will bring lingering clouds and a chance of rain or snow
showers. Temperatures will cool a little from Tuesday with -7c to
-10c aloft supporting maximum surface temperatures in the upper 30s and lower 40s.
Surface high pressure then builds in for Thursday and brings colder
air. Temperatures aloft Thursday will support maximum