Jump to content
  • Member Statistics

    17,588
    Total Members
    7,904
    Most Online
    LopezElliana
    Newest Member
    LopezElliana
    Joined

March 2-4th ... first -NAO anchored storm perhaps in years


Typhoon Tip

Recommended Posts

  • Replies 4.6k
  • Created
  • Last Reply
5 minutes ago, sbos_wx said:

It's intriguing.

It's still further south than we'd like.

The positive thing I see?

Mean LP is much further SE than a solid cluster of the members. 

It's not perfect but that's encouraging. 

If you look at it the 18z run compared to the 12z run, There are 2 members SW of the mean, The rest are all north or NW

Link to comment
Share on other sites

5 minutes ago, dryslot said:

Congrats Bermuda at 12z, Looks like most of those south and east members went north or NW at 18z

gefs_slp_lows_east_17.png

With 8 of those members south of 35 N Lat. and now none of them are even close to that at 18z, it's one reason I don't have much more faith in any of these ensembles than I do the op.

Link to comment
Share on other sites

3 minutes ago, 78Blizzard said:

With 8 of those members south of 35 N Lat. and now none of them are even close to that at 18z, it's one reason I don't have much more faith in any of these ensembles than I do the op.

I look at it like we may not see anymore south trends with none on the southern side.

Link to comment
Share on other sites

For those that don’t have weatherbell...Bastardi saying what Tip was eluding to yesterday...thicknesses are low...and once the low center passes your longitude/gets east of you, it’s going to flip to snow very/Violently fast!!    And it’s gonna snow hard.  Although he thinks it keeps moving...no stall.  Calling for 2-3 inches in NYC.  1-2 ft in Poconos and Catskills Into western New England,  6-12+ in most of SNE. 

Just thought I’d share that in the model lull right now. So we’ll see if he’s right. 

Link to comment
Share on other sites

Been fairly busy today, but I think others have spelled out the scenario well. It’s not necessarily the block causing issues (although some guidance sunk it SW) but moreso the phasing or lack thereof. I could be wrong, but I’m still not on the suppression train at this time.

All we need is Pete B too poo poo it, and it’s on. 

Link to comment
Share on other sites

Nice analysis, Legro laying it out....

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
***Significant Coastal Storm Possible Late in the Week***

The focus of the extended was mainly on potential for
significant impacts from a coastal storm late in the week...with
a weaker/lighter event Wed night.

For starters Wed...developing return flow aloft will combine
with approaching S/WV trof to produce a band of frontogenesis
along the mid level warm front. While the bulk of the forcing
for ascent looks to remain along the Nrn forecast zones...that
does leave room for some accumulating snowfall across the mtns.
That forcing will be mainly over The County...but 2 to 4 inches
are possible over the Wrn ME mtns before the best lift drifts
Ewd.

That takes us to a more significant pair of S/WVs across the
central CONUS. The Nly wave...arriving in the Pacific Northwest
Tue...and the Sly wave currently dropping down the West Coast
will begin to phase near or E of the MS River. Low pressure will
develop and track NEwd...but developing ridging over Greenland
will provide no escape N. Eventually secondary low pressure is
forecast to develop S of Srn New England and track in an Ely
direction out into the Atlantic. In a general sense this means a
slower moving system with deep Ely flow ahead of it. Model
guidance has had some run to run consistency issues...but
generally within the envelope of ensemble guidance. To me it
looks like the run to run changes are mostly related to the
degree of phasing between S/WV trofs across the central CONUS. A
weak or missed phase results in a weaker primary low and system
that gets strung out and blocked S of the forecast area. A
more complete phase leads to a stronger primary low...more
ridging ahead of the system...and enough forcing for Nwd
movement to counter- balance the developing Greenland block. The
latter scenario would lead to a more impactful and more
widespread precip event for the forecast area.

That being said...26.12z GEFS guidance is forecasting a -3 to -4
sigma H8 u wind anomaly to develop over much of Srn and central
New England by Fri morning. That type of deep Ely inflow is
typically a good signal for precip in the area...as well as Ely
upslope enhancement of precip in the White Mtns and Monadnocks.
Additionally...26.12z ECMWF EPS probabilistic guidance has a 40
to 50 percent chance of 0.50 inches QPF in a 24 hour period
ending 03.00z Sat. So I will keep the likely PoP of some
measurable precip that the multi- model consensus forecasts for
Srn NH up to the Lakes Region and far SWrn ME.
Finally...significant spread exists to the N of the ensemble
mean...with very little spread to the S. If guidance were to
shift...it would suggest to me a Nwd shift is most likely. At
least one of the S/WVs in question has not arrived over land
based sampling stations yet...so it may be another 24 hours
before model guidance gets a good handle on ingredients.

For now I will remain fairly conservative on precip...with less
than 0.50 inches QPF total across the NH/MA border. Temps will
also be on the mild side at onset...but temps aloft remain
fairly cold. With H9 temps -2 to -4C on the 26.12z ECMWF...the
most likely scenario would be a wet snow with surface temps
possibly at or above freezing. The current forecast calls for
light accumulations across Srn NH. If model guidance trends
Nwd...that would obviously increase QPF and resulting snow
amounts. Though I think it is less likely than a dry forecast or
snowier forecast...there is also a small chance that guidance
trends warmer and wetter...which could lead to some snow
melt/runoff related flooding. Greatest impacts are expected Fri
morning at this time...though changes in timing are possible at
this range.

Regardless of the interior impacts from this
system...significant coastal impacts are expected even with a
more Sly track. For information about marine interests and
coastal flooding see sections below.

 

Link to comment
Share on other sites

5 minutes ago, LongBeachSurfFreak said:

I think bastardi is right for areas over 1500’. Anything lower then that is going to be a real challenge 

Why?   Do you think the column is subfreezing 1500 and up with heavy rates but rain under that?  How does that happen and why?

Link to comment
Share on other sites

10 minutes ago, weathafella said:

Why?   Do you think the column is subfreezing 1500 and up with heavy rates but rain under that?  How does that happen and why?

Are you asking how it snows in the hills and rains in the valleys?  

What if it's 32F and snowing at 1500ft but 37F and raining at 100ft?  Precip intensity will have a lot to do with it but I don't know, you see it all the time in the mountains.

Link to comment
Share on other sites

8 minutes ago, weathafella said:

Why?   Do you think the column is subfreezing 1500 and up with heavy rates but rain under that?  Nw does that happen and why?

There is plenty of cold air aloft but the surface is rather warm. By nature of decreasing temps with height the highest elevations have the best chance of having temps cold enough to support snow. I think of this storm more in line with an early spring, rather then late winter storm 

Link to comment
Share on other sites

1 minute ago, LongBeachSurfFreak said:

There is plenty of cold air aloft but the surface is rather warm. By nature of decreasing temps with height the highest elevations have the best chance of having temps cold enough to support snow. I think of this storm more in line with an early spring, rather then late winter storm 

I think if it bombs, there will be no issues in low elevations after a period of heavy rain.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...