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January storm threat discussion #2


Ian

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After looking at that map, I don't know whether this post is good news or bad. I did a scatter diagram of all all the 4 inch or greater events since 150 except the one last year showing the NAO index value versus the AO index value. The surprising thing to me is it looked like the negative AO had a higher freuqency of 4 inch or greater event than the NAO. I think it might be because the NAO is actually measure as the difference between the heights or pressure from the Azores to Iceland which is a little east of where we want our blocking. Anyway, here's the graphic. I have a pna versus NAO graphic that will be posted with a CWG peice tomorrow or Tuesday.

post-70-0-56339700-1326678116.gif

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After looking at that map, I don't know whether this post is good news or bad. I did a scatter diagram of all all the 4 inch or greater events since 150 except the one last year showing the NAO index value versus the AO index value. The surprising thing to me is it looked like the negative AO had a higher freuqency of 4 inch or greater event than the NAO. I think it might be because the NAO is actually measure as the difference between the heights or pressure from the Azores to Iceland which is a little east of where we want our blocking. Anyway, here's the graphic. I have a pna versus NAO graphic that will be posted with a CWG peice tomorrow or Tuesday.

post-70-0-56339700-1326678116.gif

What's encouraging to me from that graphic is that there are a bunch of events with either the NAO or the AO positive (I wasn't sure which axis was measuring what), and 16 with both positive.

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Here's a challenge: how many of those were in Ninas?

The 16 events constitutes 22 percent. The other question is how many had a positive PNA. I think then the percentage goes down to about 11% if I remember correctly but that will be in Tuesday's CWG piece. I never looked at enso. That may be the next step now that I've set up the spread sheet. I just need to find daily enso readings.

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Euro weekies improve for mid February, with colder anomalies in the SE US to us, and warm anomalies over N/NE canada. The Monthly Euro sucks for the next two months but picking up on pattern changes isn't something it has done well.

You don't have access to the longer range on the Euro by any chance do you? Noticed that the GFS the last couple of days is hinting at a -NAO in the longer range that doesn't seem to be so transitory and was curious if the Euro was seeing that as well past day 10.

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You don't have access to the longer range on the Euro by any chance do you? Noticed that the GFS the last couple of days is hinting at a -NAO in the longer range that doesn't seem to be so transitory and was curious if the Euro was seeing that as well past day 10.

Yep, the Euro pay site, expensive-ish but worth it, I guess. GFS is beginning to show the pattern transition that will begin the from the end of the month into the first week of February, might be pushing the envelope though.

Now that we're closer I think it is possible to pin down the exact timeframes using the magnetic sun + current kinetic momentum as a guide. I think we see the 'transition' period from January 30 to February 7, and a sweet pattern from February 7 to February 20, followed by a break as the troughing regresses before a compensating weakness leads to another potentially wintry period from February 29 to March 15.

No spring in April or May either.

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So, the negative AO is more critical than the negative NAO?

After looking at that map, I don't know whether this post is good news or bad. I did a scatter diagram of all all the 4 inch or greater events since 150 except the one last year showing the NAO index value versus the AO index value. The surprising thing to me is it looked like the negative AO had a higher freuqency of 4 inch or greater event than the NAO. I think it might be because the NAO is actually measure as the difference between the heights or pressure from the Azores to Iceland which is a little east of where we want our blocking. Anyway, here's the graphic. I have a pna versus NAO graphic that will be posted with a CWG peice tomorrow or Tuesday.

post-70-0-56339700-1326678116.gif

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6Z GFS for BWI, DCA and IAD respectively

http://wxweb.meteost...shtml?text=KBWI

http://wxweb.meteost...shtml?text=KDCA

http://wxweb.meteost...shtml?text=KIAD

might want to save it because this run shows the best "legitimate" proged snow within 5 days we've had all winter

if nothing else, it has Zwyt's fluke(s)!

If it happens, we can call it the Zwyts storm.

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Unfortunately, the GFS ens don't have much support for the OP soluton. The Euro shows a couple of snow chances, even if they are slim, but it doesn't have the GFS type system it would seem. Hopefully the GFS op run is on to something.

I don't see any snow chances on the euro, only on the GFS which doesn't have much support from the ens members unless the euro ens members are showing storm chances. Getting a storm with a negative PNA is pretty tough unless you've got help with a negative ao and then it's still tough.

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I don't see any snow chances on the euro, only on the GFS which doesn't have much support from the ens members unless the euro ens members are showing storm chances. Getting a storm with a negative PNA is pretty tough unless you've got help with a negative ao and then it's still tough.

The only reason that I mentioned the Euro is that its snowfall maps did show a couple of shots of potential snow acc. for my area. Not so much for yours though. Regardless, I don't put any faith in that, I just wanted to see if it had the system as depicted on the the 6z GFS and it would seem that it doesn't.

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