210 likes | 484 Views
State of the Climate across Southwest Nebraska. By Matt Masek March 22, 2012. Outline. Review of 2011 – 2012 Winter Role of La Niña and Arctic Oscillation Spring Outlook One month (April) outlook Three month (April, May, June) outlook Current Drought Conditions Developing???
E N D
State of the Climate across Southwest Nebraska By Matt Masek March 22, 2012
Outline • Review of 2011 – 2012 Winter • Role of La Niña and Arctic Oscillation • Spring Outlook • One month (April) outlook • Three month (April, May, June) outlook • Current Drought Conditions • Developing??? • Quick look at the end of March Forecast
La Niña 2011-2012 La Niña - Typical Wintertime Pattern For southwestern Nebraska, closer proximity to cool temperatures and drier conditions.
What was 2011-2012 Winter? • Temperatures were above normal • Precipitation (rain/snow) was above normal • Why - last year and this year both were La Niña years • La Niña was NOT the dominate player
So what was the dominate player? • Arctic Oscillation • Based on 1000 mb height anomalies pole ward of 20° N • 2011-2012 Positive Phase Only major snowstorm for southwest Nebraska
2011-2012 WinterNorth Platte, NE Facts for the 3 month period of December, January, & February (and the last 5 years).
2011-2012 Winter North Platte, NE Temperature Summary for North PlatteDec 1, 2011 to Feb 29, 2012 Smooth tan line is normal Red and blue lines are records Precipitation Summary for North PlatteDec 1, 2011 to Feb 29, 2012 (dark blue) Dec 1 2010 to Feb 28, 2011 (magenta)Smooth red line is normal
2011-2012 Winter Imperial, NE Temperature Summary for ImperialDec 1, 2011 to Feb 29, 2012 Smooth tan line is normal Red and blue lines are records Precipitation Summary for ImperialDec 1, 2011 to Feb 29, 2012 (dark blue) Dec 1 2010 to Feb 28, 2011 (magenta)Smooth red line is normal
2011-2012 Winter Haigler, NE Temperature Summary for HaiglerDec 1, 2011 to Feb 29, 2012 Smooth tan line is normal Red and blue lines are records Precipitation Summary for HaiglerDec 1, 2011 to Feb 29, 2012 (dark blue) Dec 1 2010 to Feb 28, 2011 (magenta)Smooth red line is normal
Spring Outlook • Still have a La Niña pattern (although it is weakening) • Lingering effects from wintertime pattern and the positive AO • Polar Jet Stream – promotes more clipper systems or fast moving cold fronts • Fast moving fronts have limited time to produce significant moisture over the high plains • Drier overall atmospheric conditions favor a wide swing of temperatures from day to day • Due to warm winter over the Northern Plains there is a lack of snow cover – this will help to modify (warm) cold arctic outbreaks
Climate Prediction CenterForecast - April Higher confidence in southwest Nebraska to experience below normal precipitation while equal chances for above, below or near normal precipitation for the rest of Nebraska. Higher confidence for above normal temperatures to continue over Nebraska and much of the lower 48 states.
Climate Prediction CenterForecast - April, May, June The forecast for April, May and June are higher chance for below normal precipitation over Western Nebraska, with equal chances for above, below or near normal precipitation over central and eastern Nebraska. There is higher confidence the desert southwest and much of the south and eastern U.S. will see above normal temperatures. However over Nebraska no strong signals results in equal chances for above, below or near normal temperatures.
Climate Prediction CenterSummer Forecast – June, July, August The ENSO (El Niño Southern Oscillation) phase is expected to trend toward neutral this summer. This pushes the long range forecast to have more uncertainty for the summer across the central plains. Thus western and north central Nebraska see a forecast of equal chances for above, below or near normal precipitation and temperatures. Although recent trends for warm conditions over the desert southwest have a chance of expanding over the high plains.
Drought Developing?? • Areas to the southwest of Nebraska are being monitored for developing drought conditions over the next several months. • Due to the uncertainty of precipitation for May and June, southwest Nebraska is not expected to see the development of the drought yet. • Below normal precipitation is expected over the next month or so. April is when this area begins to receive more significant rainfall from thunderstorms. • May and June are the wettest months of the year.
Climate Prediction Center8 to 14 Day Outlook (Mar 29-Apr 4) March to end and April begins with continued warm conditions. Low pressure system tracks across the southern plains. Western Nebraska likely to miss out on the moisture with this system.
Final Thoughts for the Spring Weakening La Niña to create tricky forecast for Nebraska Higher confidence April will be warm Higher confidence areas to the southwest – dry Drought conditions may expand into southwest Nebraska, (May and June?) however uncertainty exists at this time. The End – Questions??? Questions – Matthew.Masek@noaa.gov