Riccardo Posted October 1, 2014 Share Posted October 1, 2014 The monitoring page of the “October pattern index” (OPI) is presented. The OPI index represents a analytic synthesis of the October hemispheric pattern at 500 hPa, and shows from previous studies quite a high correlation (r ≈ 0.9) with the winter mean Arctic Oscillation Index (DJF AO); this implies that the lower the OPI index is in October (negative values) and the higher will be the probability to have a weak polar vortex during the following winter. Therefore the OPI index could be a valid support tool in the seasonal forecasting of the winter season. The OPI index is calculated through a dedicated software modeling elaborating the 31 daily hemispheric October at 500 hPa. This monitoring page is updated automatically with every run of the global forecast model GFS (Global Forecast System), except the 18:00z run. The software analyzes the previous consolidated daily charts plus 10 forecast charts as given by the GFS model. For example on the 15th of October, the software calculates the OPI index based on the 15 consolidated daily charts (1-15 October) adding 10 forecast charts as given by the GFS model (16- 25 October). The definitive OPI index will be available only at the end of October, when the software will be able to elaborate all the 31 daily consolidated charts of the month. During the month the index will gradually tend to the final value starting to be reliable past the half of the month, when the consolidated charts number will overtake the forecast charts number. Finally, at the beginning of November, the official seasonal forecast for the winter 2014-2015 will be released based on the final OPI value and on the recent developments of this research whose results have been discussed and analyzed so far with Prof. Judah Cohen (Director of Seasonal Forecasting at AER) and the Italian Air Force Lt. Col. Guido Guidi. OPI Monitoring page link: http://app.til.it/opi/ This post has been promoted to an article Link to comment Share on other sites More sharing options...
QVectorman Posted October 1, 2014 Share Posted October 1, 2014 Thanks for the link. Great work! Link to comment Share on other sites More sharing options...
AvantHiatus Posted October 1, 2014 Share Posted October 1, 2014 Dang, the OPI is currently off the charts... Link to comment Share on other sites More sharing options...
donsutherland1 Posted October 1, 2014 Share Posted October 1, 2014 The monitoring page of the “October pattern index” (OPI) is presented. The OPI index represents a analytic synthesis of the October hemispheric pattern at 500 hPa, and shows from previous studies quite a high correlation (r ≈ 0.9) with the winter mean Arctic Oscillation Index (DJF AO); this implies that the lower the OPI index is in October (negative values) and the higher will be the probability to have a weak polar vortex during the following winter. Therefore the OPI index could be a valid support tool in the seasonal forecasting of the winter season. The OPI index is calculated through a dedicated software modeling elaborating the 31 daily hemispheric October at 500 hPa. This monitoring page is updated automatically with every run of the global forecast model GFS (Global Forecast System), except the 18:00z run. The software analyzes the previous consolidated daily charts plus 10 forecast charts as given by the GFS model. For example on the 15th of October, the software calculates the OPI index based on the 15 consolidated daily charts (1-15 October) adding 10 forecast charts as given by the GFS model (16- 25 October). The definitive OPI index will be available only at the end of October, when the software will be able to elaborate all the 31 daily consolidated charts of the month. During the month the index will gradually tend to the final value starting to be reliable past the half of the month, when the consolidated charts number will overtake the forecast charts number. Finally, at the beginning of November, the official seasonal forecast for the winter 2014-2015 will be released based on the final OPI value and on the recent developments of this research whose results have been discussed and analyzed so far with Prof. Judah Cohen (Director of Seasonal Forecasting at AER) and the Italian Air Force Lt. Col. Guido Guidi. OPI Monitoring page link: http://app.til.it/opi/ Welcome back, Ricardo. I look forward to the information provided in the link. Link to comment Share on other sites More sharing options...
donsutherland1 Posted October 1, 2014 Share Posted October 1, 2014 Dang, the OPI is currently off the charts... And negative. A weak polar vortex = AO-. Link to comment Share on other sites More sharing options...
WEATHER53 Posted October 1, 2014 Share Posted October 1, 2014 And negative. A weak polar vortex = AO-. Don-Would the weakness of it give it more, or less, tendency to meander around like it did last year? Link to comment Share on other sites More sharing options...
ORH_wxman Posted October 1, 2014 Share Posted October 1, 2014 Don-Would the weakness of it give it more, or less, tendency to meander around like it did last year? I'm not Don, but a weakened polar vortex would be more conductive to meridional flow...so yes, it would increase the likelyhood of a "meandering" jet. Link to comment Share on other sites More sharing options...
WEATHER53 Posted October 1, 2014 Share Posted October 1, 2014 I'm not Don, but a weakened polar vortex would be more conductive to meridional flow...so yes, it would increase the likelyhood of a "meandering" jet. I know who you are-You are Stewarts. Link to comment Share on other sites More sharing options...
AvantHiatus Posted October 1, 2014 Share Posted October 1, 2014 I know who you are-You are Stewarts. Lol, it is what it is. Link to comment Share on other sites More sharing options...
Crocodile23 Posted October 1, 2014 Share Posted October 1, 2014 The monitoring page of the “October pattern index” (OPI) is presented. The OPI index represents a analytic synthesis of the October hemispheric pattern at 500 hPa, and shows from previous studies quite a high correlation (r ≈ 0.9) with the winter mean Arctic Oscillation Index (DJF AO) Finally, at the beginning of November, the official seasonal forecast for the winter 2014-2015 will be released based on the final OPI value and on the recent developments of this research whose results have been discussed and analyzed so far with Prof. Judah Cohen (Director of Seasonal Forecasting at AER) and the Italian Air Force Lt. Col. Guido Guidi. When the official paper describing everything about the calculations of OPI and about OPI, will be released? Will there be any such official or even informal paper? Link to comment Share on other sites More sharing options...
Absolute Humidity Posted October 2, 2014 Share Posted October 2, 2014 Thanks for providing this. It will be fun to track throughout the month. Just curious about last years OPI DJF AO prediction of +1.64 when at the end of the day, the DJF AO came in at +0.188, barely positive. Was the large discrepancy a result of an X factor such as the strong pacific tropical typhones last fall or perhaps the record -EPO and stubborn Scandinavian block? Link to comment Share on other sites More sharing options...
donsutherland1 Posted October 2, 2014 Share Posted October 2, 2014 Don-Would the weakness of it give it more, or less, tendency to meander around like it did last year? It would. It's still early, but there seem to be some indications that cold and possibly snowy winter lies ahead for the Mid-Altantic and the forecast blocking episode in coming days might offer a hint. Link to comment Share on other sites More sharing options...
Ginx snewx Posted October 2, 2014 Share Posted October 2, 2014 It would. It's still early, but there seem to be some indications that cold and possibly snowy winter lies ahead for the Mid-Altantic and the forecast blocking episode in coming days might offer a hint.concur, ran a composite of all October's with AO days LESS than -2 in Oct. 15/20 winters in ORH were at or above climo snow with 11 out of those 15 significantly or well above normal. The years following winters composite 5H pattern. Link to comment Share on other sites More sharing options...
IntenseBlizzard2014 Posted October 5, 2014 Share Posted October 5, 2014 concur, ran a composite of all October's with AO days LESS than -2 in Oct. 15/20 winters in ORH were at or above climo snow with 11 out of those 15 significantly or well above normal. The years following winters composite 5H pattern. This is looking more likely with the AO nearing -4 at the first week of October. Link to comment Share on other sites More sharing options...
sebastiaan1973 Posted October 6, 2014 Share Posted October 6, 2014 OPI achieved yesterday around -2, so the average for the first 5 days is around -1. Link to comment Share on other sites More sharing options...
EasternLI Posted October 7, 2014 Share Posted October 7, 2014 Looks like a good start at least Link to comment Share on other sites More sharing options...
chionomaniac Posted October 7, 2014 Share Posted October 7, 2014 Lots of excitement with the projected OPI value so far, on this side of the Atlantic. Though after last year we will take anything! Link to comment Share on other sites More sharing options...
Riccardo Posted October 8, 2014 Author Share Posted October 8, 2014 OPI is going towards very negative values. These are still very uncertain values, but the situation is becoming interesting. Riccardo Link to comment Share on other sites More sharing options...
RaleighWx Posted October 8, 2014 Share Posted October 8, 2014 Do you have an archive of October monthly values for previous years? Link to comment Share on other sites More sharing options...
Riccardo Posted October 8, 2014 Author Share Posted October 8, 2014 Do you have an archive of October monthly values for previous years? As said in other "places", we haven't ever issued the exact OPI reanalysis values. We'll make that when we publish our research. But you can get good values by the graph that we issued last year (sorry but i can't attach it here). Hello to everyone Riccardo Link to comment Share on other sites More sharing options...
Wow Posted October 8, 2014 Share Posted October 8, 2014 Here is the graph posted last year for previous years vs. AO Link to comment Share on other sites More sharing options...
icebreaker5221 Posted October 8, 2014 Share Posted October 8, 2014 As said in other "places", we haven't ever issued the exact OPI reanalysis values. We'll make that when we publish our research. But you can get good values by the graph that we issued last year (sorry but i can't attach it here). Hello to everyone Riccardo I'm sure the plan is to cover these issues in the forthcoming paper, but I was wondering if you could fill us in on a few details... In your first paragraph you describe your methodology as an "analytic synthesis" of 500mb height patterns. Did you do an EOF analysis, EEMD, or what? Also, did you only use the period 2000-2012 for your training sample? Overall, most DJF winters during this period featured -AO, and most of the +AO winters were weak-moderate (compared to say, 93-93 or 88-89). I'm wondering if you overfitted your data and/or potentially biased the technique towards -AO. Training your EOFs one one dataset and verifying them against a separate historical dataset would be one way to demonstrate that you're unbiased and not over-fitting. Anyway, great work here, and an r value of 0.97 is truly amazing. I would just like to see how reliable the technique is before taking it as gospel. Link to comment Share on other sites More sharing options...
griteater Posted October 8, 2014 Share Posted October 8, 2014 Here's the OPI chart back to 1976 Link to comment Share on other sites More sharing options...
Deck Pic Posted October 8, 2014 Share Posted October 8, 2014 sweet link...I need to check this forum more often Link to comment Share on other sites More sharing options...
mitchnick Posted October 8, 2014 Share Posted October 8, 2014 OPI is going towards very negative values. These are still very uncertain values, but the situation is becoming interesting. Riccardo I see you had to update your graph and increase it from stopping at -3 to -4 lol it won't be too long before somebody finds an analog that suggests too low is bad; if someone does find one, please don't post it Link to comment Share on other sites More sharing options...
Ginx snewx Posted October 8, 2014 Share Posted October 8, 2014 concur, ran a composite of all October's with AO days LESS than -2 in Oct. 15/20 winters in ORH were at or above climo snow with 11 out of those 15 significantly or well above normal. The years following winters composite 5H pattern. verified now that the AO is -4 or more. I have confidence in saying ORH will experience an above normal snowfall this winter with a predominately -AO resulting in a 5H pattern conducive to snow storms. Link to comment Share on other sites More sharing options...
OSUmetstud Posted October 8, 2014 Share Posted October 8, 2014 0.91 r^2? damn Link to comment Share on other sites More sharing options...
jdrenken Posted October 8, 2014 Share Posted October 8, 2014 Looking forward to this as I also am researching upper air patterns and their correlation to the Eastern CONUS. Especially interested in your Rossby Wave correlation. Link to comment Share on other sites More sharing options...
griteater Posted October 9, 2014 Share Posted October 9, 2014 Here's a 500mb pattern comparison of -OPI vs. +OPI Octobers. Link to comment Share on other sites More sharing options...
Isotherm Posted October 9, 2014 Share Posted October 9, 2014 It's interesting that those -OPI 500mb maps coincide w/ the Aleutian trough, strongly -AO Octobers, as well as in the Atlantic, the longer term inverse correlation for Oct NAO --> DJF NAO. Link to comment Share on other sites More sharing options...
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