Bob Chill Posted November 8, 2017 Author Share Posted November 8, 2017 This panel shows a +EPO and neutralish PNA. You can see the trough is centered more over AK than digging deep over the Epac: This height pattern supports BN temps in our region because the -AO/NAO is displacing continental air southeastward. The 250mb jet pattern shows why: A different version of a +EPO/-PNA/-AO/-NAO that royally screws us is what we saw in the second half of Dec 2012. The deep trough in the east pac flooded NA with maritime air so the only thing the -AO/NAO did was displace the AN temps southward: Numerical indices don't tell the full story of what is going on. Feature placement inside of the numerical calculation can cause vastly different outcomes with what appears to be the same setup numerically. Link to comment Share on other sites More sharing options...
psuhoffman Posted November 8, 2017 Share Posted November 8, 2017 If we pull out only months with a -NAO/-PNA during a nina it shows a muddy result. Those months are Dec 1970, 2010 Jan 1971 Feb 1955, 1956, 1965 Mar 1955, 1965, 1975 The temperature are skewed cold in the Dec and Jan analogs and warm in the Feb and Mar ones FWIW Snowfall is pretty average with the following totals at DCA in order by the months in that list 5.2, 2.1, 4.8, 4.2, T, 1.9, T, 5.4, 0.3 So not awful given climo but no big hitters either. I also parsed the data for a -NAO and a neutral PNA and the results were only slightly more favorable but also note there were only 5 examples of such an outcome so the correlation may not be significant. One other problem with this is the values are for the entire month. We would really need to look at weekly data and see when the periods of NAO and PNA overlapped. But the general idea is ok but not great for snowfall. Of course the data sets are so small that I am not sure how valuable they are. Link to comment Share on other sites More sharing options...
mitchnick Posted November 8, 2017 Share Posted November 8, 2017 I told you we'd see blocking. Euro seasonal fresh off the chip courtesy NE thread. Feb sux, but there's the cold holiday forecast everyone's been waiting for. https://www.americanwx.com/bb/topic/49653-countdown-to-winter-2017-2018-thread/?do=findComment&comment=4660460 Link to comment Share on other sites More sharing options...
AfewUniversesBelowNormal Posted November 8, 2017 Share Posted November 8, 2017 6 hours ago, BristowWx said: What kind of pattern does a -PNA -AO -NAO usually yield for us? The +PNA -AO/NAO is great but sometimes just gives us dry and cold unless something can dig and turn negative. Negative NAO is number 1 for snow. With -PNA, when it's cold its dry and warms up only to rain. A lot of signals pointing toward -NAO right now but with a pretty good La Nina developing, we need at this time of the year different Pacific pattern. Could be the difference between mediocre years and 95-96. The attention given to models right now is because there is about a 65-35 ratio between November repeating for the Winter (maybe higher in established ENSO), Pacific-wise. What we want is for ridging to break through Alaska and even the Gulf of Alaska/west coast. Link to comment Share on other sites More sharing options...
Bob Chill Posted November 8, 2017 Author Share Posted November 8, 2017 1 hour ago, StormchaserChuck said: Negative NAO is number 1 for snow. With -PNA, when it's cold its dry and warms up only to rain. A lot of signals pointing toward -NAO right now but with a pretty good La Nina developing, we need at this time of the year different Pacific pattern. Could be the difference between mediocre years and 95-96. The attention given to models right now is because there is about a 65-35 ratio between November repeating for the Winter (maybe higher in established ENSO), Pacific-wise. What we want is for ridging to break through Alaska and even the Gulf of Alaska/west coast. Chuck, Wes and others like myself have sliced and diced snowfall data every which way from Sunday over the last 5-7 years or so. For the MA region, our #1 is decisively a -AO. The NAO phase change from neg to pos is a common feature for big storms but our "tell" for favorable conditions seems to point more towards the AO than the NAO. Of course it gets muddy because the two indices share space and bigger storms usually need cooperation from all 3 (ao/nao/pna). But the biggest correlation for snow in general around these parts is the AO. Link to comment Share on other sites More sharing options...
mitchnick Posted November 8, 2017 Share Posted November 8, 2017 13 minutes ago, Bob Chill said: Chuck, Wes and others like myself have sliced and diced snowfall data every which way from Sunday over the last 5-7 years or so. For the MA region, our #1 is decisively a -AO. The NAO phase change from neg to pos is a common feature for big storms but our "tell" for favorable conditions seems to point more towards the AO than the NAO. Of course it gets muddy because the two indices share space and bigger storms usually need cooperation from all 3 (ao/nao/pna). But the biggest correlation for snow in general around these parts is the AO. Yep Link to comment Share on other sites More sharing options...
AfewUniversesBelowNormal Posted November 9, 2017 Share Posted November 9, 2017 2 hours ago, Bob Chill said: Chuck, Wes and others like myself have sliced and diced snowfall data every which way from Sunday over the last 5-7 years or so. For the MA region, our #1 is decisively a -AO. The NAO phase change from neg to pos is a common feature for big storms but our "tell" for favorable conditions seems to point more towards the AO than the NAO. Of course it gets muddy because the two indices share space and bigger storms usually need cooperation from all 3 (ao/nao/pna). But the biggest correlation for snow in general around these parts is the AO. Yup, the NAO and AO are so correlated , a map of AO correlation is centered 500mb Greenland. The NAO too, maybe a few hundred miles southeast. I found -NAO is generally wetter, and -AO colder. Link to comment Share on other sites More sharing options...
uncle W Posted November 9, 2017 Share Posted November 9, 2017 most significant DCA snowfalls had a positive PNA until it got to February when more storms came during a negative pna...the few that had a negative pna was offset by a negative ao... Link to comment Share on other sites More sharing options...
Eskimo Joe Posted November 9, 2017 Share Posted November 9, 2017 With Chuck continuing to throw the 1005 - 1996 analog around, I give you this classic 6 hours of coverage from WBAL of the Blizzard of 1996. Link to comment Share on other sites More sharing options...
WxUSAF Posted November 9, 2017 Share Posted November 9, 2017 26 minutes ago, Eskimo Joe said: With Chuck continuing to throw the 1005 - 1996 analog around, I give you this classic 6 hours of coverage from WBAL of the Blizzard of 1996. Ha that’s great. I clearly remember the night before the storm and how they kept increasing the totals from 6-12”, to 12-18”, and on up from there. Link to comment Share on other sites More sharing options...
Eskimo Joe Posted November 9, 2017 Share Posted November 9, 2017 39 minutes ago, WxUSAF said: Ha that’s great. I clearly remember the night before the storm and how they kept increasing the totals from 6-12”, to 12-18”, and on up from there. That's what happened with PD II in Philly. I went to bed with a forecast of 5"-9" with "isolated 10" amounts in Delaware. To it snowing and Glen Schwartz on NBC 10 saying 10" - 20". Pure magic. The Blizzard of '96 changed how the National Guard was deployed during snow events in Maryland. Instead of waiting until things got bad, folks realized that you had to request these assets before the incident. It was kind of a watershed event for snow response. Link to comment Share on other sites More sharing options...
WxUSAF Posted November 9, 2017 Share Posted November 9, 2017 Unwelcome clear trend toward a -PDO in the NPAC for the last week. Link to comment Share on other sites More sharing options...
showmethesnow Posted November 9, 2017 Share Posted November 9, 2017 1 hour ago, WxUSAF said: Unwelcome clear trend toward a -PDO in the NPAC for the last week. I know we have seen a warming of the cold pool in the western Pacific but we aren't seeing a corresponding cooling along the Pacific coast line into Alaska. In fact we are seeing large warm anomalies building off of Mexico, baja and S California which look to be building northward. Wouldn't this be considered more of a neutral then anything else? https://www.esrl.noaa.gov/psd/map/clim/sst.anom.anim.week.html Link to comment Share on other sites More sharing options...
Bob Chill Posted November 9, 2017 Author Share Posted November 9, 2017 52 minutes ago, WxUSAF said: Unwelcome clear trend toward a -PDO in the NPAC for the last week. Unfortunately -enso and -pdo like to hold hands more often than not. Pretty rare for a +PDO during cold enso. 95-96 was a bit of an exception but even then it wasn't a strong +PDO year. Link to comment Share on other sites More sharing options...
WxUSAF Posted November 9, 2017 Share Posted November 9, 2017 1 hour ago, showmethesnow said: I know we have seen a warming of the cold pool in the western Pacific but we aren't seeing a corresponding cooling along the Pacific coast line into Alaska. In fact we are seeing large warm anomalies building off of Mexico, baja and S California which look to be building northward. Wouldn't this be considered more of a neutral then anything else? https://www.esrl.noaa.gov/psd/map/clim/sst.anom.anim.week.html Looks at TT 7 day SST anomaly cchange. It’s a classic -PDO look. Link to comment Share on other sites More sharing options...
frd Posted November 9, 2017 Share Posted November 9, 2017 17 minutes ago, WxUSAF said: Looks at TT 7 day SST anomaly cchange. It’s a classic -PDO look. Are there examples of a -PDO winter where the AO has averaged negative ? Link to comment Share on other sites More sharing options...
showmethesnow Posted November 9, 2017 Share Posted November 9, 2017 24 minutes ago, WxUSAF said: Looks at TT 7 day SST anomaly cchange. It’s a classic -PDO look. Much clearer picture. Thanks. ETA: It isn't typical to see such a large area of warm anomalies off the southwest coast in a -PDO. Is it? Link to comment Share on other sites More sharing options...
CAPE Posted November 9, 2017 Share Posted November 9, 2017 2 hours ago, showmethesnow said: Much clearer picture. Thanks. ETA: It isn't typical to see such a large area of warm anomalies off the southwest coast in a -PDO. Is it? I will admit to having trouble seeing a clear PDO phase presently. It looks ambiguous to me. Even looking at the 7 day anomaly change it doesn't look like it is clearly in a warm or cool phase. Link to comment Share on other sites More sharing options...
showmethesnow Posted November 9, 2017 Share Posted November 9, 2017 35 minutes ago, C.A.P.E. said: I will admit to having trouble seeing a clear PDO phase presently. It looks ambiguous to me. Even looking at the 7 day anomaly change it doesn't look like it is clearly in a warm or cool phase. I thought it looked somewhat neutral myself but I really don't study the SST's like some on here do, so what do I know. Maybe one day i will take a hard look into it instead of just having basic knowledge on it. I do question that warming in the southwest Pacific as to whether we will see a +PNA popping up from it. Link to comment Share on other sites More sharing options...
uncle W Posted November 9, 2017 Share Posted November 9, 2017 ao/nao/pna for major snowstorms in DCA... dates.......amount.......AO.......NAO.......PNA 11/11/87....11.5"....1.056.....0.603.....1.044 12/03/57....11.4"....0.561....-1.042.....0.534 12/11/60......8.5"...-0.916....-0.316.....1.527 12/16/73....10.2"...-0.773.....0.320.....0.340 12/19/09....16.4"...-4.651....-1.833.....0.549 12/31/70......9.3"...-1.536....-1.731....-0.192 01/07/96....17.1"...-1.094....-0.664.....0.447 01/08/88......8.0"....0.822.....0.171.....0.616 01/12/64......8.5"...-1.759....-1.180.....0.654 01/19/61......7.7"...-1.278.....0.392.....1.587 01/22/87....10.8"...-1.721....-0.981.....0.677 01/22/16....17.8"...-0.236....-0.080.....1.509 01/25/87......9.2"...-0.668....-1.009.....0.225 01/25/00......9.3"....0.382....-0.529.....0.878 01/30/66....13.8"...-3.416....-0.903.....0.401 02/02/96......8.4"...-1.847....-0.429.....0.665 02/03/61......8.3"....0.056....-0.126.....0.489 02/05/10....17.8"...-4.706....-0.766.....0.597 02/06/67....10.3"...-0.856.....0.230....-0.449 02/09/10....10.8"...-0.449....-1.136.....0.710 02/11/64......8.2"....1.038....-0.017.....0.638 02/11/83....16.6"...-1.973....-0.567.....0.845 02/11/06......8.8"...-0.175.....0.136.....1.658 02/15/58....14.4"...-1.857....-0.213....-0.472 02/18/79....18.7"....0.083....-0.093....-0.042 02/22/87....10.3"...-1.375....-1.527....-0.002 03/03/60......7.9"...-0.682.....0.249....-0.843 03/09/99......8.4"...-3.741....-0.392.....0.177 of the 28 storms...22 had a positive pna...four did not but had a negative ao that day...two were near neutral...one with a neg ao and the other with near neutral...1979 was near neutral for all three... 21 storms had a negative ao...5 were positive...2 were near neutral... 18 storms had a negative nao...3 were new neutral...7 had a positive ao... Link to comment Share on other sites More sharing options...
AfewUniversesBelowNormal Posted November 9, 2017 Share Posted November 9, 2017 Positive PNA is good chance... -AAM moving toward the poles could do this. Link to comment Share on other sites More sharing options...
CAPE Posted November 10, 2017 Share Posted November 10, 2017 11/9 Panasonic 7 day avg h5 height anomalies for 12/18 to 12/25: Link to comment Share on other sites More sharing options...
AfewUniversesBelowNormal Posted November 10, 2017 Share Posted November 10, 2017 ^Maybe we're overlooking how warm the globe is right now. Wow. Link to comment Share on other sites More sharing options...
CAPE Posted November 10, 2017 Share Posted November 10, 2017 7 hours ago, StormchaserChuck said: ^Maybe we're overlooking how warm the globe is right now. Wow. Its way out there. With all the smoothing, I don't think I would attempt to glean too much wrt temps. What I was trying to point out is the improvement out west, so even though there are suggestions the NAO may trend towards neutral, if it ends up something close to what is depicted, big picture, it is still a pretty darn good h5 look for mid to late December. Link to comment Share on other sites More sharing options...
showmethesnow Posted November 10, 2017 Share Posted November 10, 2017 7 hours ago, C.A.P.E. said: Its way out there. With all the smoothing, I don't think I would attempt to glean too much wrt temps. What I was trying to point out is the improvement out west, so even though there are suggestions the NAO may trend towards neutral, if it ends up something close to what is depicted, big picture, it is still a pretty darn good h5 look for mid to late December. Saw it earlier and thought 'Hot dam'. Even with all the smoothing that is a real cold look to me. Cross polar flow with a mean trough situated around the Mississippi. Yeah, I would take that in a heartbeat and hope we see a little southern stream loven thrown in. Link to comment Share on other sites More sharing options...
aldie 22 Posted November 10, 2017 Share Posted November 10, 2017 Chuck < anybody notice how warm Madagascar is > Chuck Link to comment Share on other sites More sharing options...
AfewUniversesBelowNormal Posted November 11, 2017 Share Posted November 11, 2017 It was the warmest October on record without El Nino or any real known cause. This should be factored in, I think. Link to comment Share on other sites More sharing options...
PhineasC Posted November 11, 2017 Share Posted November 11, 2017 Every month is the warmest ever now. Link to comment Share on other sites More sharing options...
mattie g Posted November 11, 2017 Share Posted November 11, 2017 4 hours ago, leesburg 04 said: Chuck < anybody notice how warm Madagascar is > Chuck RIP lemurs. Link to comment Share on other sites More sharing options...
mitchnick Posted November 11, 2017 Share Posted November 11, 2017 1 hour ago, StormchaserChuck said: It was the warmest October on record without El Nino or any real known cause. This should be factored in, I think. 10 day EPS 850 anomaly map for N Hemisphere. Plenty of warm and plenty of cold now. Who cares about the past at a weenie moment like this!!! Link to comment Share on other sites More sharing options...
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