venture
05-28-2010, 03:24 AM
Since I'm sure we'll see some of these questions here, as talk of the developing La Niņa ramps up...its best to look back at climatology to get examples of what it really means.
First...what years did we have a La Niņa. I'm just going to go back 50 years.
1964-1965
1970-1971
1973-1974
1975-1976
1988-1989
1995-1996
1998-1999
2000-2001
2006 (Jan-Mar)
2007-2008
2009 (First Half)
What major events occurred during the La Niņa?
Most substantial would be the effects from the Remnants of Tropical Storm Erin over Oklahoma. Information for the August 18-19, 2007 Tropical Storm Erin Remnants (http://www.srh.noaa.gov/oun/?n=events-20070819)
Prior to the start of the 1998 La Niņa we had the June 13th Tornadoes in Oklahoma City (The Oklahoma City Tornadoes of June 13, 1998 (http://www.srh.noaa.gov/oun/?n=events-19980613)). Of course, as we all remember, at the conclusion of the La Niņa in early 1999, we had the May 3rd event (The Great Plains Tornado Outbreak of May 3-4, 1999 (http://www.srh.noaa.gov/oun/?n=events-19990503)).
Finally, during and following the 2009 La Niņa we had the the February Tornadoes (February 10, 2009 Tornadoes (http://www.srh.noaa.gov/oun/?n=events-20090210)), March Winter Storm (The March 27-28, 2009 Winter Storm (http://www.srh.noaa.gov/oun/?n=events-20090327)), and the April Wildfires that greatly impacted many areas of the state (April 9, 2009 Wildfires in Oklahoma and Western North Texas (http://www.srh.noaa.gov/oun/?n=events-20090409)).
The 2009 event was pretty typical of what to normally expect. As this graphic points out, we normally have above normal temps and dry conditions. http://climate.ok.gov/images/news/lanina_map.jpg
Can we expect more tornadoes? Well here are the numbers for the spring period immediate following when the La Niņa conditions were present.
1964-1965: 74
1970-1971: 39
1973-1974: 45
1975-1976: 28
1988-1989: 20
1995-1996: 48
1998-1999: 145
2000-2001: 61
2006 (Jan-Mar): 27
2007-2008: 77
2009 (First Half): 34
Conclusion? It really makes no difference at all. We've had major outbreaks, and some of our slowest seasons. Oklahoma Climate is always going to be in a state of flux, we are however in a period that is wetter and warmer now. Since the early 1980s, we have been in the wettest historical period for the last 110+ years. Yes there are parts of the state that have had droughts and such, this is a state average. The middle part of this decade we were dry as a state, but that is the first time we trended on the dry side since the Mid 70s to early 80s. Temperature wise from the 90s up until a year ago we were in the warmest period we've seen since the 50s...and the 20s to 40s before then. We have trended on the cool side here recently, likely due to the increased precip we've seen.
Our severe weather expectations are going to be ruled by more than the temps in the East Pac. As our environment keeps shifting around, we'll have periods of a lot of severe weather and then seasons where storm spotters are bored to tears (2002-03, 2005-06, and 2009 are examples). But it only takes on event to make the averages work. Our 60 year average right now is 53 tornadoes per year. We up until May we had only 3. May's preliminary numbers are at 52, which would make it the 5th business May in the last 60 years. Majority of those tornadoes came from 2-3 events.
So depending on how strong the La Niņa gets will determine how we get effected. If it is relatively weak, we might see slightly warmer temps but the storm track won't be pushed too far north. If we get a strong one, the storm track could be pushed well into the Northern Plains or further and leaving us dry and hot with the potential for drought conditions and rough fire season come Fall/Winter. Of course, with that said, as noted in the Tropics discussion thread...with increased Atlantic basin activity expected, this could also mean a greater chance of seeing a Texas landfall and get the remnants of a tropical system to move over the state which would keep us from drying out too quick.
So for now it is wait and see. Personally I'd rather see a weaker one, even if it means keeping the storm track close. I don't want to see a repeat of the wildfires of 2009...this is not an event I want any of us to relive.
http://www.srh.noaa.gov/images/oun/wxevents/20090409/Fire_Update_040909_2313.jpg
First...what years did we have a La Niņa. I'm just going to go back 50 years.
1964-1965
1970-1971
1973-1974
1975-1976
1988-1989
1995-1996
1998-1999
2000-2001
2006 (Jan-Mar)
2007-2008
2009 (First Half)
What major events occurred during the La Niņa?
Most substantial would be the effects from the Remnants of Tropical Storm Erin over Oklahoma. Information for the August 18-19, 2007 Tropical Storm Erin Remnants (http://www.srh.noaa.gov/oun/?n=events-20070819)
Prior to the start of the 1998 La Niņa we had the June 13th Tornadoes in Oklahoma City (The Oklahoma City Tornadoes of June 13, 1998 (http://www.srh.noaa.gov/oun/?n=events-19980613)). Of course, as we all remember, at the conclusion of the La Niņa in early 1999, we had the May 3rd event (The Great Plains Tornado Outbreak of May 3-4, 1999 (http://www.srh.noaa.gov/oun/?n=events-19990503)).
Finally, during and following the 2009 La Niņa we had the the February Tornadoes (February 10, 2009 Tornadoes (http://www.srh.noaa.gov/oun/?n=events-20090210)), March Winter Storm (The March 27-28, 2009 Winter Storm (http://www.srh.noaa.gov/oun/?n=events-20090327)), and the April Wildfires that greatly impacted many areas of the state (April 9, 2009 Wildfires in Oklahoma and Western North Texas (http://www.srh.noaa.gov/oun/?n=events-20090409)).
The 2009 event was pretty typical of what to normally expect. As this graphic points out, we normally have above normal temps and dry conditions. http://climate.ok.gov/images/news/lanina_map.jpg
Can we expect more tornadoes? Well here are the numbers for the spring period immediate following when the La Niņa conditions were present.
1964-1965: 74
1970-1971: 39
1973-1974: 45
1975-1976: 28
1988-1989: 20
1995-1996: 48
1998-1999: 145
2000-2001: 61
2006 (Jan-Mar): 27
2007-2008: 77
2009 (First Half): 34
Conclusion? It really makes no difference at all. We've had major outbreaks, and some of our slowest seasons. Oklahoma Climate is always going to be in a state of flux, we are however in a period that is wetter and warmer now. Since the early 1980s, we have been in the wettest historical period for the last 110+ years. Yes there are parts of the state that have had droughts and such, this is a state average. The middle part of this decade we were dry as a state, but that is the first time we trended on the dry side since the Mid 70s to early 80s. Temperature wise from the 90s up until a year ago we were in the warmest period we've seen since the 50s...and the 20s to 40s before then. We have trended on the cool side here recently, likely due to the increased precip we've seen.
Our severe weather expectations are going to be ruled by more than the temps in the East Pac. As our environment keeps shifting around, we'll have periods of a lot of severe weather and then seasons where storm spotters are bored to tears (2002-03, 2005-06, and 2009 are examples). But it only takes on event to make the averages work. Our 60 year average right now is 53 tornadoes per year. We up until May we had only 3. May's preliminary numbers are at 52, which would make it the 5th business May in the last 60 years. Majority of those tornadoes came from 2-3 events.
So depending on how strong the La Niņa gets will determine how we get effected. If it is relatively weak, we might see slightly warmer temps but the storm track won't be pushed too far north. If we get a strong one, the storm track could be pushed well into the Northern Plains or further and leaving us dry and hot with the potential for drought conditions and rough fire season come Fall/Winter. Of course, with that said, as noted in the Tropics discussion thread...with increased Atlantic basin activity expected, this could also mean a greater chance of seeing a Texas landfall and get the remnants of a tropical system to move over the state which would keep us from drying out too quick.
So for now it is wait and see. Personally I'd rather see a weaker one, even if it means keeping the storm track close. I don't want to see a repeat of the wildfires of 2009...this is not an event I want any of us to relive.
http://www.srh.noaa.gov/images/oun/wxevents/20090409/Fire_Update_040909_2313.jpg