A look ahead at the Feb 3-10 Period - Technical Discussion (Updated to Feb 15th)

[ORH_wxman]

I figured I would start a thread focusing on the Feb 3-10 period as it has become a focus of a lot of long range guidance for increased storm chances.

 

We'll look at what we have in that upcoming week on the ensemble guidance:

 

 

 

First off, is a typhoon_tip favorite...the PNA index. We are entering a period of -PNA, however, we see some brief periods where it tries to spike back up into positive or at least near neutral...this is evident on the GEFS PNA data:

 

 

 

 

 

 

This is a sign that shortwaves have a bit more assistance to amplify in the eastern U.S...even if the system stubbornly digs in the south and southwest, the +PNA would try and induce a split flow which would increase confluence to our north...hence increasing the winter storm threat even on a storm that tries to initially track west.

 

 

 

 

The ECMWF ensemble mean even at 144 hours shows a significant system developing in the southern states. I use this 144 panel because it is not so far out that it is very unreliable. The ensemble mean should start getting an idea here.

 

 

 

 

 

In case we were wondering about spread...the agreement is pretty good for a pattern that supports a significant system coming out of the south:

 

 

 

 

 

 

 

Now, this doesn't mean New England is getting a big winter storm. But it does mean that chances are very high a storm system will be moving northeast out of the southern plains/SE which is a good starting point for a New England winter storm. Things can still go wrong from that 144 hour point...either too far NW or it gets squashed. Even the 144h panel itself isn't guaranteed, but it is high probability that it will be fairly close to the right idea.

 

 

Further down the road, the pattern continues in the general -EPO/-PNA/+NAO configuration, with another brief PNA spike around Feb 10-11th. That is getting far out there, but this would increase the chances for another storm. Especially given the excellent temperature gradient that is going to exist over the southern tier of the CONUS. It is a very favorable pattern for moisture laden systems developing in that region.

 

 

I expect temperatures to average below normal during this period over New England but not overly brutal. Especially given that there may be some storminess nearby. It looks like a chance at more severe cold after this period could be lurking...however, by this point we are out into D12-15 of the forecast.

 

[CoastalWx]

Pretty much man. It's a time that really can deliver the goods for sure with juicy systems that have the potential to be drawn out of the upper level configuration is right. Remarkable consensus for next week right now.

[Ginx snewx]

Another run another solution, GFS, oh my

[CoastalWx]

That's a cold run...smidge south too. Good hit for many.

[dryslot]

Something that I think would be pretty cool is that a few of you mets from here and some of the other regions do a radio show outlining some of your thoughts on the pattern going forward on the remainder of winter seeing we have had no HECS this year so far

[SouthCoastMA]

Yeah one heckuva front ender on this run. HP is stronger as well and in decent position

[free_man]

Yeah, the 2/5 system is a bit slower and colder at 0z.  Not good for CT RI/SE MA, though...sleet or rain but I didn't look at the soundings for specifics.

[Ginx snewx]

Yeah, the 2/5 system is a bit slower and colder at 0z. Not good for CT, though...sleet or rain but I didn't look at the soundings for specifics.

NW of 84 gets hammered, but way to early for soundings

[SouthCoastMA]

Yeah, the 2/5 system is a bit slower and colder at 0z. Not good for CT, though...sleet or rain but I didn't look at the soundings for specifics.

Everyone starts as snow on this run..and several inches before any changeover. Just referring to the GFS run.

[Ginx snewx]

That storm is a frigging beast as depicted, lol wow

[H2Otown_WX]

Is this a thread for the 2/5 event, I'm confused...should there be a specific thread for that?  Is this off-topic?

I think Will (ORH_wxman) started this thread to encompass two threats; one on 2/5 and another around 2/10. A specific thread for 2/5 isn't really necessary yet since it's almost a week away.

[ORH_wxman]

Ensemble guidance from the ECWMF last continued to be clustered fairly closely at 132-144 hours for the first threat. The OP model run was on the more amplified side of the ensemble spaghetti plots. The ensemble guidance continued to show a threat for another larger scale system around Feb 9th.

 

Both threats go in line with many of the analog patterns from late January that showed the liklihood of a larger storm increased after the Feb 3-4 period.

[Baroclinic Zone]

Lets keep this thread for serious discussion.  IE, model, pattern, etc.  Use the other Feb thread if you want to banter.  We are going to step up moderation going forward and are trying to limit the amount of OT that goes on in the Discussion Threads.

[Baroclinic Zone]

I think Will (ORH_wxman) started this thread to encompass two threats; one on 2/5 and another around 2/10. A specific thread for 2/5 isn't really necessary yet since it's almost a week away.

See my post above.  We are really trying to keep the Discussion threads more scientific with minimal banter, ot stuff.  Everything else can get put in the Main Discussion Thread.

[TauntonBlizzard2013]

That storm behind the 5th storm on the euro is big. That's a huge hit if it verified of course

[jamesnichols1989]

Of course the EURO is a big hit for the 5th and 9th, normally this time period has brought us some nice storms of the past.  But this pattern has a tendency to over amplify and stick a warm nose of air into the SNE region bringing mild ocean air into eastern parts of MA, RI and CT.

[CoastalWx]

Of course the EURO is a big hit for the 5th and 9th, normally this time period has brought us some nice storms of the past.  But this pattern has a tendency to over amplify and stick a warm nose of air into the SNE region bringing mild ocean air into eastern parts of MA, RI and CT.

 

It's fine as modeled.  It definitely could leave most of us with 33F and rain...but I don't really see that as of now.

[CoastalWx]

GFS looks a tick south and colder. That's a big front end thump.

[CoastalWx]

Wow, that's a huge 6 hr dump..lol. Kind if an interesting storm. BOS will turn into a light 34F rain and then flash freeze followed by maybe a coating of snow at the end.

 

Almost has a cold tuck look. Hmm.

[40/70 Benchmark]

It's fine as modeled.  It definitely could leave most of us with 33F and rain...but I don't really see that as of now.

Those SSTs have taken a beating , too....have got to factor that in.

[TalcottWx]

Those SSTs have taken a beating , too....have got to factor that in.

36 way out in the ocean off eastern mass. 32 in bos harbour. Cold

[CoastalWx]

Those SSTs have taken a beating , too....have got to factor that in.

 

Yeah the marine layer isn't that bad. If the 850s could ever stay like -3C or colder it would be all snow.

[CoastalWx]

BOS harbor is between 38-39F. Fluctuates.

[HoarfrostHubb]

Wow, that's a huge 6 hr dump..lol. Kind if an interesting storm. BOS will turn into a light 34F rain and then flash freeze followed by maybe a coating of snow at the end.

 

Almost has a cold tuck look. Hmm.

That hour 156 has that look

[CoastalWx]

That hour 156 has that look

 

You can see it on the srfc temps too. I know it doesn't look like it verbatim...but the fact that the GFS has cold temps bottled up near PSM tells me Ray will be below 32 no doubt if that GFS were to happen. Perhaps even close to BOS.  That weak secondary riding east of the Cape would turn the flow nrly. Again, just speaking of this run. We still have a long way to go.

[ORH_wxman]

The GEFS are signaling a pretty cold and snowy period near the Feb 8-10 range. The analog guidance suggest that February 1972 is becoming a dominant analog...as well as other snowy periods such as early February 1975, early February 1979, and to a lesser extent late Jan/early Feb 1954.

 

 

 

 

 

 

 

The analog patterns also signal at significant cold in the northern tier later in the period.

[HoarfrostHubb]

It has been a while since modeling has spit out (for a few runs now) something that looks like this. Nothing historic, but more typical than some of these systems we have had so far

 

me likey

[powderfreak]

Wow, that's a huge 6 hr dump..lol. Kind if an interesting storm. BOS will turn into a light 34F rain and then flash freeze followed by maybe a coating of snow at the end.

Almost has a cold tuck look. Hmm.

I'd take that...you guys get a hellacious thump to IP/ZR and dryslot as further north up here we just quietly snow for like 24 hours. But still a solution to produce a widespread snow for many folks.

[TalcottWx]

BOS harbor is between 38-39F. Fluctuates.

Was referring to the buoy near the tea party

[CoastalWx]

Was referring to the buoy near the tea party

 

I usually like to look more at the source region for that kind of thing, but yeah....the near shore waters usually are a little colder. Ironically, the waters aren't really all that cold as you would think, thanks to the past few years of warmth.