wxsniss

And Box map updated...

fwiw Harvey leaning with RGEM more than 0z Euro / 6z NAM

6z RGEM almost identical to 0z RGEM

Stubborn with that subsidence area for multiple runs now, tight deform and coastal front band flanking Boston metro

South coast / southeast MA does well consistently

a keeper of an AFD from Taunton 341am...

some excerpts:

Area forecast discussion
National Weather Service Taunton Massachusetts
341 am EST Monday Jan 26 2015

Short term /6 PM this evening through Wednesday/...

*** potentially historic winter storm ramps up tonight ***

* blizzard conditions expected
* up to 2 feet of snow for many areas with higher amounts possible
* damaging winds likely coast especially cape/islands...gusts 60 to 75 miles per hour
* pockets of major coastal flooding possible along the eastern Massachusetts
coast

Overview...
confidence remains high for a historical blizzard impacting
southern New England beginning late in the day today.
However...that does not mean there are not some mesoscale
differences which will need to be monitored as we approaches. At
issue at this point...are differences in the final low pressure depth
prior to the occlusion process ranging from 978 hpa on the NAM/CMC
to 984 on the GFS. At odds also...is the likelihood of two
distinct banded snow features...the first...a long and significant
deformation/f-gen band stretching from coastal main into interior
southern New England...the tip of which could range anywhere from the
CT valley to metropolitan-west and the Merrimack valley. Available WRF
outputs are in disagreement here...with the nmm further west with
the heavier banding...while the arw is suggesting the east. The other
area will likely be form central Rhode Island through about the S shore/bos
metropolitan of mass as a coastal front develops and wavers inland. So it
is likely that there will actually be two bullseyes of snow
totals to watch...where storm total snowfall is likely to exceed 2
feet. Finally...this banding location will likely be dependent on
final track...which are still in some mesoscale-scale dispute with the
GFS remaining more progressive and outside the 40/70 benchmark
while the ecwmf/NAM are just inside and much slower...stalling the
low pressure only about 50 nm southeast of ack. Therefore...the banding and
axis of 2.5-3.0 inch total quantitative precipitation forecast amounts are likely to waver a
bit...and will need to be updated as the event is unfolding. Will
try to show this two-bullseye snowfall somewhat with this
update...but given that this will be high impact storm across all
of southern New England wholesale changes will note be made.


Total snowfall/blizzard...

As stated there is the likelihood of two banding locations...one
from typical middle-level deformation and negative epv...with the other
closer to the surface in vicinity of of the coastal front across Rhode Island-southeast Massachusetts or
near the I-95 corridor. While nailing these down is difficult
almost 24 hours out...mesoscale models do at the very least
indicate that within either of these bands...dendritic growth will
likely be near a maximum and with bands of very negative epv...2-3
in/hour snowfall amounts within either of these bands are likely
beginning late tonight...and continuing well into the day on Tuesday
as these bands slowly pivot and begin a slow shift to the east. Given
the slow movement...this also suggests that some areas could see
snowfall amounts of about a foot in 6 hours or even less.

Therefore...feel the mention of 2+ feet of total snowfall across
interior to east Massachusetts/Rhode Island and even northern CT is possible...with a few
spots approaching 3 feet not out of the question. Regarding the
blizzards...BUFKIT mixing profiles still support winds near blizz
criteria along with this potentially heavy snow bands within the
current blizzard warnings...so not planning on making any
adjustments at this time.

With the chance for lower snow ratios nearer to the coastal front
locations...colocated with the stronger winds...will have to watch
portions of southeast Massachusetts /particularly near the coast/ for the higher
likelihood of damage/power outages. Higher ratios further inland
/colder air/ are expected.

It appears ocean enhancement will likely delay the end time
especially for portions of the S shore...southeast Massachusetts and east Rhode Island late Tuesday
into Wednesday...which may snow until after noon on Wednesday. However...by
Tuesday night...expect slowly diminishing snowfall rates from west to east.

Winds...
GFS has backed down a bit on the low level jet...now supporting 65 knots at
h92 from southern Rhode Island through bos and points southeast. However...NAM/ECMWF
continue lean closer to 70-80 knots. BUFKIT mixing profiles support
at least 75-80 percent of this momentum being mixed especially
closer to the coastlines. Therefore...can still support wind gusts
approaching hurricane velocity near the shore...particularly the
outer arm of Cape Cod and Nantucket although this tapers
inland...still could see some wind gusts 50-60 miles per hour as far inland
as Rhode Island and the I-95 corridor. As mentioned above...where this
coincides with lower ratio /more water laden/ snow...could produce
more tree damage and therefore potentially more power outages.

Coastal flooding...
for more on this...please see the coastal flooding section below.

&&

 

just looking at GGEM... persistent subsidence zone in all the models over metrowest Boston, all the banding features really just sit in same place while system stalls

Two points wxsniss as I know you understand I've got no motives behind what I'm saying.

 

I really believe the lean here was convective feedback was the reason the euro was right and the growing consensus of the others wrong.  May still be the case, but for the reasons I outlined above I'd actually think if the experts were so sure feedback was involved in this particular case DUE to the capture and hook, it would discount the western most solutions to some extent.

 

I'm not sure this lobe of vorticity is invalid.  I think we're just seeing a slightly delayed capture because the initial impulse (as Phil and an AFD mentioned earlier) is running a wee bit fast.  So as a result instead of this thing spinning up from 70 or 71, it's more like 69 or 69.5.

 

GFS/RGEM/NAM are all in very solid general agreement. 

 

Wxniss, lastly...it's unlikely this bobble is done. 

100% agree... was raising the comparison of 18z RGEM to Saturday afternoon GGEM / EURO to make the point that these eastward tugs by pieces of vorticity swinging way past 70W may have some truth to it

(tough night to be obligated away from the internet... waiting until my better half falls asleep lol)

Clinch, Tip, 0z RGEM showing a dual-lobe system that GGEM depicted 24-36 hours ago. I posted a map of this from the CMC, Tip posted a map from the Euro.

All resulting from a stray lobe of vorticity that shoots out farther east.

Interesting the RGEM is now showing the same. And still not ready to call this the final outcome.

this looks alot like 18z RGEM, maxima in southeast and central MA

yeah Jerry hrs 45-51 we dry slot on this run... also don't get the finale best for last band as storm fills in and move away

difference between 20 vs. 30 inches

Oh man did that later capture deliver... Hour 39 wow!!!

These little fluctuations will continue, the jacks can't be locked >24hours out if prior blockbusters tell us anything.

slightly later capture did the trick

NYC folks pulled the trigger too soon, was Euro vs. the rest which was all trending east

thru 30 hr notable tick east vs. 18z

Here's more octosno porn

wow... that video is a keeper! great stuff!

makes you realize how painfully Boston metro got shafted in that storm... the intro act to an absurdly bad winter.