An area of low pressure developed south of New England Friday night the 16th, moved along the Southern New England coast on Saturday the 17th, and moved to the Maritimes by Sunday the 18th. This combined with cold air already in place over the region brought a broad area of snow over Southern New England.
Every event with a place to put it; 20 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS BOX wrote it up.
An area of low pressure developed south of New England Friday night the 16th, moved along the Southern New England coast on Saturday the 17th, and moved to the Maritimes by Sunday the 18th. This combined with cold air already in place over the region brought a broad area of snow over Southern New England.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Boston/Norton, MA wrote its last area forecast discussion before the first event at Dec 16, 10:29 PM EST, 1 hour 31 minutes earlier.
Area Forecast Discussion
National Weather Service Taunton MA
1029 PM EST Fri Dec 16 2016
.SYNOPSIS...
Low pressure will result in accumulating snow developing toward
daybreak Saturday, which will end as a period of ice across the
interior and plain rain along and southeast of the Boston to
Providence corridor by early Saturday afternoon. Wintry
precipitation will switch to rain Sat night and linger into Sun.
Drier and cooler weather return for Monday and Tuesday.
&&
.NEAR TERM /UNTIL MIDNIGHT TONIGHT/...
High pressure is moving offshore with a southerly flow over NY/PA.
South jet of 40-50 knots at 925 mb and 900 mb is aimed at and
bringing overrunning over NY and PA, where radar shows pcpn aloft
while surface observations show cloud bases at 6000 to 9000 feet
and no surface pcpn. Most of the observed pcpn is up to a
Toronto-Toledo line.
This is a fair distance to cover. Meanwhile the favorable
overrunning is ahead of the pcpn and well to our west. Based on
the 10 pm observations, the low level air over Srn New England is
starting the night drier than forecast.
All of this suggests dry weather for most of the night, with pcpn
possible late. This remains in line with model QPF forecasts, but
is slower than model probability of pcpn (POP) forecasts. Based on
what we are seeing we will adjust current forecasts of the latter
toward the former. This brings chc pops to the west 06-07Z and to
the east 08-09Z...likely pops a cpl hours later...and categorical
a couple hours after that.
Mid level clouds are moving across our area and the trend remains
for skies clouding over. Temperatures radiated a little more than
expected this evening in scattered locations, but with the onset
of clouds this cooling should end and temps should even start
moving up a little.
&&
.SHORT TERM /MIDNIGHT THROUGH 6 PM SATURDAY/...
Highlights...
***Accumulating snow overspreads the region toward daybreak and
falls moderate to heavy for a few hours away from Cape/Islands***
***Snow likely changes to rain along and southeast of the Boston to
Providence corridor by late Sat AM and to a period of light freezing
rain across the interior***
***Flash Freeze possible in the Boston Metro area by mid-late
Saturday afternoon***
Details....
1) Timing and Ptype...
A developing southwest low level jet of 40 to 50 knots riding over
the cold dome at the surface should result in snow overspreading the
region between 6 and 10z from southwest to northeast. Initially,
may see some ocean effect snow showers across the Cape/Islands as
850T still around -13C at 6z. However, given that the high pressure
is moving off the coast southerly flow off the mild ocean will
quickly change ptype to rain across the Islands by 10z and the Cape
between 11z and 13z. Expect this transition to work onto the south
coast by 14z and probably into the Boston to Providence corridor
between 15z and 17z.
However, given most guidance shows a weak surface low tracking near
the south coast the arctic dome of cold air will be tough to scour
out across the interior. Therefore, areas just northwest of Boston
to Providence should see snow change to a period of freezing rain
between 15z and 18z.
Deeper moisture will be exiting the region by late afternoon as the
wave of low pressure passes to our east. Will mainly be left with
pockets of drizzle and freezing drizzle.
2) Snow and Ice Accretion Potential...
Fairly high confidence in snowfall amounts across the interior. A
period of decent omega in the snow growth region should result in
several hours of moderate to perhaps even briefly heavy snow,
roughly between 10z and 16z in most locations /where ptype is still
snow/. That makes us fairly confident in 4 to 6 inches of snow to
the northwest of a Boston to Providence line. There is a low
probability that there are localized 7 inch or so amounts, but
confidence not high enough to upgrade to a winter storm warning.
As mentioned above, confidence in snow amounts diminishes some in
the Boston to Providence corridor. Since it might be snowing close
to an inch per hour near the transition time, a small difference in
timing would result in a difference. Currently, we depicted the
most likely scenario being 2 to 4 inches. A quicker change over
would result in just an inch or two, while if it is delayed 4 to 6
inch amounts would be possible particularly in the Boston area.
Finally, expect 1 to 3 inches of snow along the south coast where a
quicker change to rain is expected.
Given the track of the weak surface low pressure system, do not
expect low level cold air to get scoured out much to the northwest
of the Boston to Providence corridor. This should allow snow to
change to a period of freezing rain before tapering off by mid
afternoon. Ice accretion should generally be less than a tenth of an
inch, but can not rule out some localized higher amounts.
However, certainly not expecting anything that would create damage.
3) Flash Freeze Potential in Boston and perhaps even further south...
This appears to be a classic setup for a potential flash freeze in
northeast MA including the Boston metro area by late Saturday
afternoon. As the wave of low pressure moves east of the region,
shallow low level cold air will likely rush back into the Boston
metro area dropping temps quickly below freezing. This may result
in the potential of a flash freeze along with pockets of freezing
drizzle by late afternoon. There is even a lower risk that this
makes its way into the Providence to Taunton corridor, but will have
to watch the latest trends mainly from our mesoscale models.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
*/ Highlights...
- Wet weather with breezy S winds late Saturday night into Sunday
- Shot of Arctic air Sunday night into Monday
- Seasonable conditions throughout the week
Overview and model preferences...
Our final shot at truly arctic influenced (although modified) air
arrives following the brief warm up featured late in the weekend,
then lingers into Tue. After this, with most major teleconnections
(save for PNA) trending positive will see true arctic air become
locked up at the poles under a strengthened and nearly symmetrical
polar vortex. Therefore, the trend toward the coming holiday
weekend will feature for seasonable to possibly even seasonably
mild conditions. GEFS/ECENS probabilities support this thinking
with reasonably high probabilities that outside of lows, most
temps will remain above freezing for a majority of the week, a
strong signal for as far out as days 6-8.
That is not to say, that with in the SW-NE oriented upper lvl
flow regime there are not some shortwaves rotating out across the
CONUS having originated near the Aleutian vortex. However, these
are likely to be relatively progressive. Given this, timing of any
one feature remains a low confidence forecast at this time, so
will be continuing with the ensemble mean weighted blend we have
used the last few days, as it will best represent most
possibilities within the envelope.
Details...
Sun night thru Sun...
Initial concern, as reflected by the short-termed forecaster, is
a brief flash freeze during the early evening hours until
mesoscale low pres is able to shift NE, influenced by a strong S
LLJ which will counter the Nly isallobaric flow. Once the low pres
passes during the evening, sfc temps should once again begin to
rise rapidly as H92 temps surge towards +10C, ending the risk. Sfc
temps will not meet the typical diurnal curve, as warming should
continue through the overnight hours into Sun morning, so the
reflected lows overnight of below freezing to the upper 30s will
actually occur during the evening hours. Highs Sun, with such warm
mid lvl temps are likely to warm into the upper 40s and 50s.
Initially, some drizzle is expected thanks to loss of ice nuclei
from drying aloft. However, as higher PWAT air is advected in with
the LLJ, a change to full-scale rain will occur during the
overnight hours thanks to increased mid lvl F-gen associated with
the approaching cold front. The front will be slow moving as it
parallels the LLJ, suggesting rain will linger across most of the
area well into the daylight hours Sun, before gradually ending
from NW-SE through the afternoon and evening hours.
Looking at precipitation, PWATS near 400 percent of normal or 3+
standard deviations above climatology will be moving in, possibly
reaching as high as 1.5 inches. The influence of the LLJ, combined
with steep lapse rates (reflected in TT values over 40) and
K-values near 30, could lead to pockets of heavy rain as the front
approaches late night into mid day Sun. Widespread QPF amounts
range from about 0.50-0.75 inches, which seems like a reasonable
start, but would not be surprised if a few spots approach an inch
with this feature given the dynamics involved which are mentioned
above. Not expecting flood issues as a result of these values, but
then any leftover snow/ice, some urban flooding spots are possible
mainly due to clogging drains and extra melt. CAA/dry air
advection will move in rapidly on the back side of the front such
that H92 temps could be as low as -8C by Sun evening. While it is
most likely that the dry air will move in faster than the cold,
suggesting an end to precip as rain, a few spots could see a brief
change back to snow before precip actually stops entirely.
One other note, given the very strong LLJ within the warm sector
Sun night (near 40 kt at H92 and 60 kt at H85), may need to watch
from some gusty winds. However, agree with previous forecaster's
assessment, as bufkit profiles still show robust inversion with
H85 warm tongue which would mitigate mixing of this momentum to
the sfc. Still, could be a bit more breezy than experienced during
the snow for Sat, or the rain for Sun.
Sun night into Mon morning...
Am still concerned of rapid freezing during the overnight hours
especially as skies clear and ageostrophic flow becomes strongly
N. H92 temps will dip as low as -12C by 12Z Mon, and this should
be reflected in the sfc, with temps dropping below freezing and
possibly even the upper teens and 20s by the AM hours. Any
remaining water on sfc could freeze quickly leading to black ice.
Still concerned about the AM commute Mon which could feature
slippery conditions on area road/walkways left untreated.
Mon and Tue...
Last true polar-influenced airmass associated with the deep wave
lifting through New England. H92 temps are coolest Monday, dipping
to -8C to -10C, with warming to -2C to -4C on Tuesday. Highs Mon,
therefore should remain mostly in the 30s, followed by mid 30s to
low 40s on Tue. Mon night mins will be cold thanks to radiational
cooling within a nearly stationary 1040mb high pres. Could easily
see a few single digits in the sheltered valleys with teens
elsewhere.
Wed...
Models in reasonable agreement that the first shortwave passage
within the mean SW-NE oriented jet on the periphery of strong high
pres across the SW Atlantic will arrive on Wed. Sfc reflection is
likely to be a weak cold frontal passage attendant to low pres
passing through QC. It's likely dry however, as the airmass
associated with the stable high pres over S New England remains
quite dry itself. Temperatures likely return to near seasonal
normals.
Late next week...
As mentioned earlier, given the progressive flow regime wedged
between strong upper lvl high pres the SE and the polar air locked
in well to the N, confluence will limit shortwave ability to
deepen, thereby amplifying the pattern significantly. Not to say
there could be some precipitation to deal with but there is
considerable spread between deterministic models and their
respective ensemble members . However, we can say that seasonable,
to seasonably mild temperatures appear more likely than not given
the loss of true arctic influence into the lower latitudes.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Short Term /through Saturday/...
Overnight...
VFR with cloud bases 6000 to 9000 feet. After 2 am these lower to
4000-6000 feet...4 to 6 am lower to 1500 to 2500 feet. Light snow
moves in after 3 am from southwest to northeast. with rates
increasing toward sunrise and vsbys falling to IFR toward 7 am.
Saturday...Moderate to high confidence in trends, but lower
confidence in specific timing.
Snow should then fall moderate to briefly heavy for a few hours
in most locations, resulting in IFR-LIFR conditions. Ptype
transitions to rain by 14z along the south coast and probably
between 15z and 17z in the BOS to PVD corridor. To the northwest
of Bos-Pvd snow should change to a period of freezing rain between
15z and 18z for most of the region before ending.
Bulk of steady precipitation should be over by early Saturday
afternoon. Pockets of drizzle and freezing drizzle may persist
into the early evening.
KBOS TAF...Snow should arrive between 7z and 10z with a period of
moderate snow /LIFR/ conditions around the morning push. Ptype
likely transitions to rain between 15z and 17z before ending.
However, colder air will likely race back into the region from the
NNW by late afternoon potentially resulting in a flash freeze.
Some freezing drizzle is also possible.
KBDL TAF...Snow develops between 6z and 8z. The snow should fall
moderately for several hours before transitioning to a period of
freezing rain between 15 and 18z. Steady precipitation ends
thereafter.
Outlook /Saturday Night through Wednesday/...
Sat night into Sun...Moderate confidence.
Mainly IFR conditions, drizzle, and rain. Some light freezing
drizzle along with freezing temperatures leading to some icing
possible mainly Sat evening, but expect warming late Sat night
into Sun morning. Rain gradually ends from NW to SE late afternoon
Sun, continuing into Sun night.
Mon thru Wed...High confidence.
Mainly VFR with high pres.
&&
.MARINE...
Forecaster Confidence Levels.
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Short Term /through Saturday/...
Tonight...High confidence. High pressure over the waters moves
east overnight. Seas and winds should remain below small craft
thresholds.
Saturday...Moderate to high confidence. High pressure moving off
the coast will result in a strong south to southwest low level jet.
Mixing will be be limited as much milder air aloft moves over the
waters, but still expect southwest gusts of 30 knots and seas
building to between 6 and 10 feet across our southern waters. Low
risk for a brief period of gale force wind gusts across these
waters, but given developing inversion felt small craft headlines
were more representative.
Outlook /Saturday Night through Wednesday/...
Saturday night through Monday...High confidence in trends.
Seas will be high enough to maintain small craft advisories for
much of the waters through the period. They will build to a peak
of 10-12 ft over the ocean waters early Sun, then gradually
diminish into the day on Mon. S winds may reach about 25 kt at
times Sat night into early Sun, then shift to the W behind a
front. During the shift another period with gusts to around 25 kt
is likely, otherwise winds remain below small craft thresholds.
Some rain/fog reduce vsbys.
Tue and Wed...
Mainly quiet boating weather, with the only caveat later Tue and
Tue night as SW winds reach 20-25 kt with a slight building of
seas mainly across the N waters into the Gulf of Maine.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Winter Weather Advisory until 3 PM EST Saturday for CTZ002>004.
MA...Winter Weather Advisory until 1 PM EST Saturday for MAZ007-
013>022.
Winter Weather Advisory until 3 PM EST Saturday for MAZ002>006-
008>012-026.
RI...Winter Weather Advisory until 1 PM EST Saturday for RIZ002>007.
Winter Weather Advisory until 3 PM EST Saturday for RIZ001.
MARINE...Small Craft Advisory from 7 AM to 7 PM EST Saturday for
ANZ231>235-237.
Small Craft Advisory from 7 AM Saturday to 7 AM EST Sunday for
ANZ250-254>256.
&&
SYNOPSIS...Frank/Doody
NEAR TERM...WTB/Frank/Doody
SHORT TERM...Frank
LONG TERM...Doody
AVIATION...Frank/Doody
MARINE...Frank/DoodyHAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE TAUNTON MA 427 PM EST FRI DEC 16 2016 CTZ002>004-MAZ002>006-008>012-026-RIZ001-172130- HARTFORD CT-TOLLAND CT-WINDHAM CT-WESTERN FRANKLIN MA- EASTERN FRANKLIN MA-NORTHERN WORCESTER MA-CENTRAL MIDDLESEX MA- WESTERN ESSEX MA-WESTERN HAMPSHIRE MA-WESTERN HAMPDEN MA- EASTERN HAMPSHIRE MA-EASTERN HAMPDEN MA-SOUTHERN WORCESTER MA- NORTHERN MIDDLESEX MA-NORTHWEST PROVIDENCE RI- 427 PM EST FRI DEC 16 2016 ...WINTER WEATHER ADVISORY IN EFFECT FROM 1 AM TO 3 PM EST SATURDAY... THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHERN CONNECTICUT...CENTRAL MASSACHUSETTS...EASTERN MASSACHUSETTS...NORTHEASTERN MASSACHUSETTS...WESTERN MASSACHUSETTS AND NORTHERN RHODE ISLAND. .DAY ONE...TONIGHT. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. WINTER WEATHER ADVISORY. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. WINTER WEATHER ADVISORY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. MAZ007-013>022-RIZ002>007-172130- EASTERN ESSEX MA-WESTERN NORFOLK MA-SOUTHEAST MIDDLESEX MA- SUFFOLK MA-EASTERN NORFOLK MA-NORTHERN BRISTOL MA- WESTERN PLYMOUTH MA-EASTERN PLYMOUTH MA-SOUTHERN BRISTOL MA- SOUTHERN PLYMOUTH MA-BARNSTABLE MA-SOUTHEAST PROVIDENCE RI- WESTERN KENT RI-EASTERN KENT RI-BRISTOL RI-WASHINGTON RI-NEWPORT RI- 427 PM EST FRI DEC 16 2016 ...WINTER WEATHER ADVISORY IN EFFECT FROM 1 AM TO 1 PM EST SATURDAY... THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN MASSACHUSETTS...NORTHEASTERN MASSACHUSETTS...SOUTHEASTERN MASSACHUSETTS...NORTHERN RHODE ISLAND AND SOUTHERN RHODE ISLAND. .DAY ONE...TONIGHT. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. WINTER WEATHER ADVISORY. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. WINTER WEATHER ADVISORY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. MAZ023-024-RIZ008-172130- DUKES MA-NANTUCKET MA-BLOCK ISLAND RI- 427 PM EST FRI DEC 16 2016 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEASTERN MASSACHUSETTS AND SOUTHERN RHODE ISLAND. .DAY ONE...TONIGHT. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. ANZ230>237-250-251-254>256-172130- BOSTON HARBOR-CAPE COD BAY-NANTUCKET SOUND-VINEYARD SOUND- BUZZARDS BAY-RHODE ISLAND SOUND-NARRAGANSETT BAY-BLOCK ISLAND SOUND- COASTAL WATERS EAST OF IPSWICH BAY AND THE STELLWAGEN BANK NATIONAL MARINE SANCTUARY-MASSACHUSETTS BAY AND IPSWICH BAY- COASTAL WATERS FROM PROVINCETOWN MA TO CHATHAM MA TO NANTUCKET MA OUT 20 NM- COASTAL WATERS EXTENDING OUT TO 25 NM SOUTH OF MARTHAS VINEYARD AND NANTUCKET- COASTAL WATERS FROM MONTAUK NY TO MARTHAS VINEYARD EXTENDING OUT TO 20 NM SOUTH OF BLOCK ISLAND- 427 PM EST FRI DEC 16 2016 THIS HAZARDOUS WEATHER OUTLOOK IS FOR MASSACHUSETTS AND RHODE ISLAND COASTAL WATERS. .DAY ONE...TONIGHT. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. FOR THE LATEST UPDATES...PLEASE VISIT OUR WEBPAGE AT WWW.WEATHER.GOV/BOSTON YOU CAN FOLLOW US ON FACEBOOK AT WWW.FACEBOOK.COM/NWSBOSTON YOU CAN FOLLOW US ON TWITTER AT @NWSBOSTON
The national radar mosaic for the moment the first event began.
13 winter weather, 7 winter storm. Local standard time, as filed.
Seven to eight inches of snow fell on western Franklin County.
Six to eight inches of snow fell on eastern Franklin County.
Six to eight inches of snow fell on western Hampshire County.
Five to six inches of snow fell on eastern Hampshire County.
Six to eight inches of snow fell on eastern Hampden County.
Five to eight inches of snow fell on northern Worcester County.
Three to six inches of snow fell on southern Worcester County.
Five to six inches of snow fell on northwest Middlesex County.
Three to six inches of snow fell on western Middlesex County.
Three to five inches of snow fell on southeast Middlesex County.
Four to five inches of snow fell on western Essex County.
Two to five inches of snow fell on eastern Essex County.
Two to five inches of snow fell on Suffolk County.
Three to six inches of snow fell on western Norfolk County.
Three to four inches of snow fell on eastern Norfolk County.
Three to four inches of snow fell on northern Bristol County.
Two to three inches of snow fell on southern Bristol County.
Three to four inches of snow fell on western Plymouth County.
Two to three inches of snow fell on eastern Plymouth County.
Two to three inches of snow fell on Barnstable County.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Massachusetts in 2016Every state in 2016This day in weather historyWarnings in Massachusetts, December 2016
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 669236, 669237, 669238, 669239, 669240, 669241, 669243, 669244, 669245, 669246, 669247, 669248, 669249, 669250, 669251, 669252, 669253, 669254, 669255, 669256.