wxsniss

Just getting out of work, will try to do some intense verification analysis of handling of vorticity lobes, SLP placement, and radar. To summarize guidance outcomes, correct me if I missed something: 12z Euro + 12z NAM: both have 2 maxima, over western CT + eastern MA, with Euro being much further southwest into NYC 12z/18z RGEM: further east, with 18z basically putting deformation band over eastern MA RAP/HRRR: ? Not gonna even look at GFS, it dropped a turd before Feb 2013 too. One thing at first glance on 18z RGEM vs. others... that intense lobe of vorticity much further north than anything depicted on RAP for 0z, and also not on Euro or NAM for 0z:

This may be the best run for Boston metro / eastern MA we've seen so far Multiple spots Boston - Naraganaset - Plymouth aiming for 30+

One maxima western/central CT Second maxima South Shore down to Naragansset Bay to Plymouth

Messenger hour 24 holy ****, MUCH better for southeast / eastern MA

not sure what people in other forums are seeing definite tick northeast on this run thru 24h

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

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

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.