Jump to content
  • Member Statistics

    17,585
    Total Members
    7,904
    Most Online
    23Yankee
    Newest Member
    23Yankee
    Joined

Active mid December with multiple event potential


Typhoon Tip
 Share

Recommended Posts

27 minutes ago, Greg said:

Generally it's a moderate to heavy snowstorm for many places but major or blockbuster, no. Can't change the definition, based on the impact.

This is definitely a Major storm for SNE.  It’s not a blockbuster at this point, but if 12+ falls, this is certainly a Major winter storm for SNE. 

Link to comment
Share on other sites

Just now, WinterWolf said:

This is definitely a Major storm for SNE.  It’s not a blockbuster at this point, but if 12+ falls, this is certainly a Major winter storm for SNE. 

It's not a minimum of 12"+ wide spread, at least not yet. 8-16" seems to be reasonable at this point. Read the BOX from the National Weather Service I posted earlier.

Link to comment
Share on other sites

Just now, JC-CT said:

The BOX?

AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
645 PM EST Tue Dec 15 2020

.SYNOPSIS...
Tonight and Wednesday are quiet and cold. A coastal storm will
bring heavy snow, strong winds, and minor coastal flooding to
the region Wednesday night into Thursday. High pressure builds
in for late in the workweek into the weekend. Colder than
average temperatures for late in the week begin to moderate by
the weekend.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
645 PM update...

Diminishing north winds tonight as high pres builds to the
north. Just some high clouds overspreading SNE this evening
but clouds are thin and shouldn`t have much impact on low temps
tonight. Lows ranging from the single numbers north central and
west MA to teens elsewhere, except 20s outer Cape and ACK.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/...
Highlights

* A significant winter storm capable of producing heavy snowfall
  late Wed into Thu afternoon across our region is expected.
* The potential exists for at least part of our area to receive over
  a foot of snow. However, the overall pattern is progressive, which
  means it is hard-pressed to see snowfall accumulations much over
  12 inches.
* If the low pressure tracks a little further north, areas towards
  the south coast and the Cape/Islands will have mixing issues,
  which will cut down on the snow totals.
* The biggest concern with the system will be heavy snowfall rates
  and given the antecedent cold air mass, snow will accumulate
  immediately on all surfaces upon onset.

A significant winter storm capable of heavy snowfall across much of
the region is becoming more likely, with abundant southern stream
moisture and antecedent cold air in play for potential
significant, plowable snowfall. Mesowest obs show widespread dew
points in the single digits with a few spots even below zero,
indicative of a fresh injection of cold, dry air mass. The
exceptions are the Cape and Islands and areas towards the MA/RI
immediate South Coast, where it will mix with and change over to
rain. Some uncertainty still remains, however, on the northern
edge of heavy snowfall. The 12z guidance has shown a northward
trend with the heavy precipitation, which is why we have
expanded Winter Storm headlines to include our western and
northern zones.

Looking at the 12z suite of guidance including the HREF, the system
is forecast to remain fairly progressive as the H5 low crosses from
NJ into SNE. There are some hints that the H5 low could weaken a
little slower between 12z and 18z, but very little to suggest
bumping up the current forecast too much. Also, the track of the H5
low is a little further north and its track along the MA/RI south
coast would suggest that areas towards and along the MA/RI south
coast, including the Cape & Islands will mix likely with and change
to rain after an initial thump, which will cut down on snow totals.
This also means that areas further N&W will also come into play for
heavier snow accumulations, which is why we expanded the Winter
Storm Watches to our entire CWA with the morning update.

A potential red flag against some of the eye-popping totals shown by
deterministic guidance is the relative lack of deepening of the
secondary low. Ensemble members keep the low in the high 990s or low
1000s, which indicates a lack of deepening or cyclogenesis required
for the system to have more staying power and reduce the potential
for totals much higher than a foot at this time. Also, this reduces
the chance for blizzard conditions though it will still be quite
windy with the pressure gradient thanks to the 1035 mb high to our
north. Overall, given the progressive pattern and the deamplifying
H5 shortwave, we are inclined to go with a widespread 8-12 inches
for our CWA with lesser amounts towards the S Coast. Could some
locations get more than a foot? Absolutely, but it is hard pressed
to see amounts over 15 inches at this time.

The H5 upper low that will play a critical role in the Nor`easter
has shown up the water vapor satellite imagery over the Texas
Panhandle. A cursory glance seems to suggest that the GFS and NAM
have initialized rather well. A closer look suggests that the NAM
may have initialized the ridge over the Northern Rockies a little
too much. These are very fine margins and subtle differences, but
could have an outsized role downstream and storm impacts on our
area.

Overall, we are becoming more confident of a significant, but
not blockbuster winter storm. Widespread accumulations of 8 to
12 inches are forecast, with lesser amounts towards the MA/RI
south coast and the Cape and Islands, where it is expected to
mix with and change over to rain after the initial thump of
snow.
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...