weatherwiz

Developing split flow should make medium-range forecasting all the more fun coming up

Kinda touched upon this in a response to Steve but you gotta be careful with just looking at the chart. compare how the models handle the pattern around the time the AO drops...it’s more in relation to a transient ridge which moves across the southern-tier of the AO domain...the drop does not appear to be in relation to any change with the overall strength or structure of the PV. I haven’t checked what the models are forecasting in terms of temps in the stratosphere but I would assume they’re still going to be quite cold. if we wanted to relay on the Arctic for help we would need to (actually would have already needed to) start seeing changes occur within the stratosphere and to the PV now. Having this major increase in the AO will only further strengthen the PV...especially given how intense the westerlies are in the strat

oh of course not...however, the influences it is having on the pattern...nearly controlling the entire hemispheric pattern is just making that probability extremely low. Just look at how much trouble we've had. I think there have been instances this winter where the PAC was actually not bad at all but the Arctic was just so unfavorable.

Moreso just another indicator that we're headed towards spring. But I totally agree with your post...I'm not saying we won't see any more snow or snow events at all...hell we've had snow events into April before lol...but what I'm just saying is (which agrees with what you said) deep winter is not coming. If we are going to get snow events as we get into March we are likely going to have to rely on something crazy to happen (thread the needle type deal?...I certainly don't think we will get any pattern support for it. If the PV wasn't as potent and strong as it was I would argue against my thoughts...but we've seen before when the PV is this strong it just doesn't break down. It's signal is just too overwhelming too to have other teleconnections overpower it. Here's 50mb zonal winds since February 1...the westerlies are through the roof. It would take a great deal of time for these to weaken and even when that occurred there is typically a 2-4 week lag between the response on the PV

been reading tweets and posts about changes coming since the end of December...it's now mid-February. spring training has started...we're almost a month away from the equinox...we are now exiting peak climo and slowly hedging towards spring climo.

The index itself can change very quickly...absolutely, however, the implications of those changes don't happen as quickly. But sort of dissecting that AO drop it appears it's related to some ridging which slides through the southern sections of the AO domain and isn't necessarily related to the structural change of the AO...which is going to be the most important when wanting a full-scale long-duration pattern change. Even during that projected AO drop the PV still looks to stay relatively intact and strong.

Speaking of February 1990 as an analog...wasn't that spring a big tornado producing year out in the Plains??? That would bode well for me

I think it's b/c the strongest anomalies are a bit outside of the NAO domain...although it's possible that Hurrell's NAO method (which I believe has a larger domain) would reflect a much more positive value than the CPC

Winter is done...it's over. It's already mid-February. We aren't going to get any help from the Arctic whatsoever...by the time any changes take place we'll be into the spring season...should changes take place. Given how strongly positive the AO will become again the PV isn't just going to weaken and breakdown in a few days or even a few weeks. Even with a somewhat favorable Pacific the Arctic signal is just too strong.

The AO forecast is beyond ridiculous...+6 to +7SD....yikes

As long as it is extremely active when I go out to OK at the end of May I will take 40's and 50's into July...I would make that trade.

It's going to relax in time to give us a crappy April and May. 40's and 50's with drizzle and overcast

I woke up to a coating (if you could call it that) of snow...was pouring like crazy though so perhaps had more than a coating before we flipped to rain. Driving on the highway basically into Wallingford was a disaster...I don't understand this state...highway completely dark with no lights. Very scary to drive in these conditions.

We are down to 79-days to go!!! Once the 0z GFS completes tonight..it will be into March (well technically still Feb 29 but 0z March 1st!!!) which means there would only be ONE full month left in the model world before May

Approaching mid-February! Is that pattern change still coming? Getting closer and closer to spring

I have that same problem. I've sort of gotten away from it though...moreso just b/c of time. but I liked doing it in hopes of teaching those who are interested in learning more...or sparking them to gain an interest. I think the reason why I've done it is b/c when I was trying to learn I killed for in-depth discussions...I wasn't looking to be told the answers...but be presented with enough of a basic background to pave the path for me to explore more.

There is growing consensus in the medium range for a long-duration winter weather event to impact at least a portion of New England. A rather significant trough is expected to dig into the western U.S. over the weekend and continue to amplify as it progresses through the central states. The response will be a strong ridge in the east. There are uncertainties, however, regarding the structure of the ridge across the Northeast as there are indications this will flatten out some. This is key as the trough and associated cold front approach the stage may be set for a long-duration overrunning event across New England; including the potential for a significant icing event.

Fine...this one too long anyways. I have good luck with the severe threads. give me a minute

yeah Wednesday into Thursday.

Verbatim looks like we get some ice...with the worse up in the Litchfield Hills (in terms of CT) with a significant ice event eastern NY into central New England

I'm down for some significant icing and power outages

It's only 6-hour totals but they are quite hefty across New England for ice. that would be a pretty big disaster

I don't want to muck up the Feb thread anymore but going back to what Scott was saying earlier about the warming oceans this is pretty insane. Small sample size being used of course but here's a list of the three previous weak EL Nino's and three weak EL Nino's from the 1970's Here is moderate One thing to keep in mind though is not taking into account the phase of the PDO/AMO. IIRC the AMO was negative in the 1970's as was the PDO. AMO has been positive since the mid 1990's.

I wonder if this is the type of storm that can really change the pattern...how this storm evolves as it moves northeast looks like it could really buckle things and we can get pretty chilly behind it.

This reminds me...remember that whole ridiculous idea the a KU storm couldn't occur during a La Nina (think it was La Nina)...and then it finally happened I remember we had a few discussions about this either at a conference or a g2g Anyways though...I don't disagree with you at all...plus it's all about presentation and backing up your analysis...which you do just about as good as anyone.