bluewave Posted November 5, 2013 Share Posted November 5, 2013 The models are hinting at a possible record Aleutian blocking event for the month of November. I haven't been able to find any November dates going back to 1950 when a 588 dm ridge build close to or over the Aleutians. Both the Euro and GFS are hinting at 500 mb height anomalies above +500 m. One of the strongest ridges that I have been able to find near that region occurred in June 1953. This impressive amplification is coming during a year that has seen the strongest year to date blocking near Alaska since 1989. Link to comment Share on other sites More sharing options...
jordanwx Posted November 5, 2013 Share Posted November 5, 2013 18z GFS has +4.2 SDs. Impressive Link to comment Share on other sites More sharing options...
andyhb Posted November 5, 2013 Share Posted November 5, 2013 >594 dm ridge near the Aleutians in November, that's insanity. Link to comment Share on other sites More sharing options...
OKpowdah Posted November 5, 2013 Share Posted November 5, 2013 Looking through 12-hourly observed soundings at PASY (Shemya, AK in the Aleutians), here are the maximum 500mb heights in November from 1973 to 2012: 1973, 5760 1974, 5830 1975, 5540 1976, 5540 1977, 5660 1978, 5660 1979, 5650 1980, 5530 1981, 5630 1982, 5590 1983, 5340 1984, 5510 1985, 5660 1986, 5600 1987, 5530 1988, 5580 1989, 5650 1990, 5770 1991, 5490 1992, 5580 1993, 5720 1994, 5610 1995, 5700 1996, 5710 1997, 5300 1998, 5300 1999, 5610 2000, 5950 2001, 5550 2002, 5550 2003, 5590 2004, 5540 2005, 5640 2006, 5750 2007, 5500 2008, 5570 2009, 5620 2010, 5620 2011, 5490 2012, 5650 Link to comment Share on other sites More sharing options...
OKpowdah Posted November 5, 2013 Share Posted November 5, 2013 And probably closer to the region of interest, PASN, St. Paul 1973, 5740 1974, 5450 1975, 5580 1976, 5490 1977, 5510 1978, 5600 1979, 5540 1980, 5510 1981, 5480 1982, 5430 1983, 5310 1984, 5550 1985, 5610 1986, 5600 1987, 5430 1988, 5470 1989, 5440 1990, 5690 1991, 5450 1992, 5500 1993, 5600 1994, 5600 1995, 5650 1996, 5640 1997, 5480 1998, 5430 1999, 5510 2000, 5400 2001, 5440 2002, 5440 2003, 5600 2004, 5390 2005, 5590 2006, 5670 2007, 5440 2008, 5500 2009, 5510 2010, 5760 2011, 5560 2012, 5610 Link to comment Share on other sites More sharing options...
bluewave Posted November 5, 2013 Author Share Posted November 5, 2013 Looking through 12-hourly observed soundings at PASY (Shemya, AK in the Aleutians), here are the maximum 500mb heights in November from 1973 to 2012: 1973, 5760 1974, 5830 1975, 5540 1976, 5540 1977, 5660 1978, 5660 1979, 5650 1980, 5530 1981, 5630 1982, 5590 1983, 5340 1984, 5510 1985, 5660 1986, 5600 1987, 5530 1988, 5580 1989, 5650 1990, 5770 1991, 5490 1992, 5580 1993, 5720 1994, 5610 1995, 5700 1996, 5710 1997, 5300 1998, 5300 1999, 5610 2000, 5950 2001, 5550 2002, 5550 2003, 5590 2004, 5540 2005, 5640 2006, 5750 2007, 5500 2008, 5570 2009, 5620 2010, 5620 2011, 5490 2012, 5650 That 2000 500 mb looks like it's an error that was logged into the observation. November 2000 featured a trough in that region with no daily heights approaching that level. But thanks for researching all the different heights for November. Link to comment Share on other sites More sharing options...
heavy_wx Posted November 5, 2013 Share Posted November 5, 2013 Here is the 0z euro ensemble mean forecast for 11/15 at 0z. Link to comment Share on other sites More sharing options...
bluewave Posted November 5, 2013 Author Share Posted November 5, 2013 >594 dm ridge near the Aleutians in November, that's insanity. We'll have to see how the forecast gets refined as we approach that date. But 588 dm near the Aleutians this time of year would be in excess of a +500 m anomaly. The Euro and GFS ensembles are both over 500 meters. Instant weather maps now has 500 mb height anomalies from the GFS which has been consistently above 500 meters the last few days. The last +500 m anomaly for the Northern Hemisphere in general was last March with the record breaking -AO. http://www.instantweathermaps.com/GFS-php/showmap-nh.php?run=2013110506&var=GPA_500mb&hour=192 Link to comment Share on other sites More sharing options...
Jonger Posted November 5, 2013 Share Posted November 5, 2013 Weren't the heights low near that spot in much of winter 2011-2012? Could this be a good thing for winter fans in the US? Link to comment Share on other sites More sharing options...
griteater Posted November 5, 2013 Share Posted November 5, 2013 We actually saw a very similar pattern at the end of November last year, but with a -AO. Link to comment Share on other sites More sharing options...
GaWx Posted November 5, 2013 Share Posted November 5, 2013 Weren't the heights low near that spot in much of winter 2011-2012? Could this be a good thing for winter fans in the US? For the eastern US, the polar opposite, an Aleutian LOW is what you want to dominate if you want the best shot at a cold winter. Link to comment Share on other sites More sharing options...
bluewave Posted November 5, 2013 Author Share Posted November 5, 2013 We actually saw a very similar pattern at the end of November last year, but with a -AO. We did get some blocking out there, but it was much weaker than the current forecast. Link to comment Share on other sites More sharing options...
Jonger Posted November 5, 2013 Share Posted November 5, 2013 For the eastern US, the polar opposite, an Aleutian LOW is what you want to dominate if you want the best shot at a cold winter. Lets hope that it coming 2 weeks early means it will gobble up 2 weeks less MET winter, 3 straight years of bad starts to winter will be a huge bummer. Link to comment Share on other sites More sharing options...
griteater Posted November 5, 2013 Share Posted November 5, 2013 We did get some blocking out there, but it was much weaker than the current forecast. True, I was just struck by the similarities of the Aleutian ridging up into the Bering Strait, with the trough off the west coast Link to comment Share on other sites More sharing options...
Jonger Posted November 5, 2013 Share Posted November 5, 2013 Its pretty long-range, but it doesn't appear to maintain its strength more than a couple days. Link to comment Share on other sites More sharing options...
bluewave Posted November 5, 2013 Author Share Posted November 5, 2013 True, I was just struck by the similarities of the Aleutian ridging up into the Bering Strait, with the trough off the west coast Yeah, the big story this year after the record -AO in March has been how the NE Pacific has been dominating the NH blocking. This is the strongest NE Pacific blocking year from January through October since 1989. Numerous records for warmth have occurred in Alaska over the summer and again in October. Link to comment Share on other sites More sharing options...
Ginx snewx Posted November 5, 2013 Share Posted November 5, 2013 For the eastern US, the polar opposite, an Aleutian LOW is what you want to dominate if you want the best shot at a cold winter.-EPO with ridging into AK is what we want, Link to comment Share on other sites More sharing options...
GaWx Posted November 5, 2013 Share Posted November 5, 2013 -EPO with ridging into AK is what we want, Gulf of Alaska into E. mainland of Alaska ridging teleconnects with eastern US troughing. However, that doesn't mean Aleutian ridging. That typically means Aleutian troughing. What is best is Aleutian troughing, Gulf of Alaska/E. Mainland Alaska/US west coast ridging. Remember that the center of the intense forecasted ridge is near 170 W. If you want a trough near the east coast of the US, the ridge usually needs to be much further east, closer to 140 W. I should add that New England is often in a different situation from much of the rest of the E US. You are sticking way out east of the SE and Midwest for example. So, you could still get cold coming SE from Canada when most others in the E US miss the bulk of it. Perhaps in the currently discussed situation, your area might have a better chance for some cold coming down from SE Canada. Link to comment Share on other sites More sharing options...
tacoman25 Posted November 5, 2013 Share Posted November 5, 2013 Some other years that had highly anomalous blocking over Alaska/Aleutians in October and November. 1950 1965 1966 1970 1973 1978 1985 1990 1993 1996 2003 2006 2012 Link to comment Share on other sites More sharing options...
Isotherm Posted November 5, 2013 Share Posted November 5, 2013 I should add that New England is often in a different situation from much of the rest of the E US. You are sticking way out east of the SE and Midwest for example. So, you could still get cold coming SE from Canada when most others in the E US miss the bulk of it. Perhaps in the currently discussed situation, your area might have a better chance for some cold coming down from SE Canada. This is especially true in November as wavelengths are generally shorter than they'd being during the DJF time frame. Thus, while strong low-latitude Aleutian ridging in mid winter generally yields widespread blowtorching of the Eastern US, that same H5 pattern in November actually leaves room for short waves to dive southeast toward New England. Latest guidance demonstrates this well as a potentially strong shot of cold air could push into New England Nov 10th-15th via the sfc ridge (1035+mb). Link to comment Share on other sites More sharing options...
CAD_Wedge_NC Posted November 6, 2013 Share Posted November 6, 2013 Some other years that had highly anomalous blocking over Alaska/Aleutians in October and November. 1950 1965 1966 1970 1973 1978 1985 1990 1993 1996 2003 2006 2012 The underlined years saw record Nov lows set in the east along with the all time coldest Nov outbreak in 1950. Of course some of the years listed saw record highs in Nov as well. Roll forward to the following Jan and there are some impressive cold outbreaks for some of those years like 1994,1966, and 1986. There was also some warm stretches thrown in there. Looks like a roller coaster ride coming up based off the analogs. Link to comment Share on other sites More sharing options...
jordanwx Posted November 6, 2013 Share Posted November 6, 2013 Here is the 0z euro ensemble mean forecast for 11/15 at 0z. ecmAnom240.png Where was this image (below) plotted/taken from? Link to comment Share on other sites More sharing options...
heavy_wx Posted November 6, 2013 Share Posted November 6, 2013 Where was this image (below) plotted/taken from? I plotted it with NCL using the freely available data from the ECMWF. http://www.ecmwf.int/products/additional/gts_downloads.html#grib2essential Link to comment Share on other sites More sharing options...
bluewave Posted November 6, 2013 Author Share Posted November 6, 2013 The Euro and the ensemble mean continue to show a stronger ridge near the Aleutians than we have seen in November since 1950. The 588 dm line building near the Aleutians would be greater than the previous strongest November ridges in that location since 1950. The previous record dates are 11-29-50, 11-25-70, and 11-17-10. Forecast 11-29-50 11-25-70 11-17-10 Link to comment Share on other sites More sharing options...
das Posted November 6, 2013 Share Posted November 6, 2013 Where was this image (below) plotted/taken from? I plotted it with NCL using the freely available data from the ECMWF. http://www.ecmwf.int/products/additional/gts_downloads.html#grib2essential jordanwx, in case you are wondering, NCL is a fast and powerful data plotter distributed by the National Center for Atmospheric Research (NCAR). http://www.ncl.ucar.edu/ Config and learning is somewhat steep but well worth the time. Link to comment Share on other sites More sharing options...
Mallow Posted November 7, 2013 Share Posted November 7, 2013 Does this have any relation to our super-typhoon? EDIT: If so, not a lot. The main storm pumping up this ridge appears to be an extratropical one. Link to comment Share on other sites More sharing options...
bluewave Posted November 7, 2013 Author Share Posted November 7, 2013 Does this have any relation to our super-typhoon? EDIT: If so, not a lot. The main storm pumping up this ridge appears to be an extratropical one. The interesting thing is that this is occurring against the strongest NE Pacific blocking year to date since 1989. But you can see how that big extratropical low is putting this ridge over the top so to speak. Link to comment Share on other sites More sharing options...
jordanwx Posted November 7, 2013 Share Posted November 7, 2013 I plotted it with NCL using the freely available data from the ECMWF. http://www.ecmwf.int/products/additional/gts_downloads.html#grib2essential jordanwx, in case you are wondering, NCL is a fast and powerful data plotter distributed by the National Center for Atmospheric Research (NCAR). http://www.ncl.ucar.edu/ Config and learning is somewhat steep but well worth the time. Cool, thanks guys. Link to comment Share on other sites More sharing options...
OKpowdah Posted November 8, 2013 Share Posted November 8, 2013 12z GFS through day 5, maximum 500mb heights: PASY: 5771m PASN: 5754m Link to comment Share on other sites More sharing options...
bluewave Posted November 8, 2013 Author Share Posted November 8, 2013 Heights building to 582-588 over a portion of the Aleutians would be the greatest that I have been able to find for the month of November there going back to 1950. That would be close to a +530 meter anomaly for that part of the world. Link to comment Share on other sites More sharing options...
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