TropicalM. D. Eastin The El-Nino Southern Oscillation (ENSO) La Nina ImpactsEl Nino Impacts.
North American Impacts of El Nino
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Transcript of North American Impacts of El Nino
North American Impacts of El Nino
Jon M Schrage
r(-SOI3mrm,OLR’), r(-SOI3mrm,’@200), r(-SOI3mrm,winds@ 200)
40N
20N
0
20S
40S
140E 180 140W 100W
Rossby Wave Source
• Conservation of Absolute Vorticity
• The twin anticyclones aloft are what initially displaces the air parcels.
• Results in a pattern of troughs and ridges far downstream.
PNA PATTERN
PNA PATTERN
The following slides are composites from January 1998.
http://www.cdc.noaa.gov/cgi-bin/Composites/printpage.pl
500mb heights
1000mb T
1000mb T
OLR
OLR
Precip
Precip
Sea Level Pressure
Sea Level Pressure
Changnon
• What counted as an impact of El Nino?– The general monthly and seasonal
temperature and precipitation conditions– The lack of Atlantic hurricanes– Snowstorms?– An event attributed to El Nino by a NOAA
employee speaking in an official capacity
Changnon
• Losses during El Nino:– Rain in the southeast (including Florida)
• Unusual tornadoes• Crop damage by rain• Reduced tourism• Direct damage from storms
Changnon
• Losses during El Nino:– Storms:
• October, 1997 in Midwest• January, 1998 in New England• April, 1998 in Ohio Valley
Changnon
• Losses during El Nino:– Drought in Hawaii– Ski resorts in Midwest– Producers of salt, natural gas, snowmobiles,
etc.– Fires in Florida
Changnon
• Benefits during El Nino:– Mild Winter in Midwest:
• Few lives lost (13 vs. 757!)• Lower fuel costs (10% nationally!)• Fewer airline and shipping delays• Longer construction season• Snow removal costs
Changnon
• Benefits of El Nino:– No landfalling hurricanes
• 13 lives, $5 billion, saved
Changnon
• Benefits of El Nino:– Difficult to quantify:
• Improvement in lifestyle• Recharging reservoirs
Changnon
• Losses:– Human lives lost: 189– Economic costs: $4.2 billion
• Benefits:– Human lives saved: 850– Economic gains: $19.6 billion
Changnon
• Lessons:
• “…the need to focus on both the good and bad impacts of predicted weather conditions. The media tends to focus only on the negative outcomes.”
Changnon
• Lessons:– “News… writers tend to approach “local”
experts for interpretations of the events… [resulting] in widely different interpretations…”
Changnon
• Lessons:– “…all weather conditions produce winners and
losers”
Changnon
• Lessons:– “…predicting future impacts on lives and the
economy due to expected weather is likely as difficult as making accurate long range weather predictions.”