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2015 Summer Weather Outlook

2015 Summer Weather Outlook. Temperatures, Precipitation, Drought, and Hurricanes. Visit www.ercot.com/about/weather for daily and seasonal weather updates.

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2015 Summer Weather Outlook

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  1. 2015 Summer Weather Outlook Temperatures, Precipitation, Drought, and Hurricanes

  2. Visit www.ercot.com/about/weather for daily and seasonal weather updates.

  3. The past two springs (2013 and 2014) have averaged at slightly cooler than normal. That’s certainly possible for 2015 as well, though I believe there will be enough warmer potential mid-to-late spring that this season may average a bit warmer than the past couple of springs. But not to the very warm levels of 2011 and 2012.

  4. Introduction Today’s weather outlook is intended to offer a preliminary look at the summer temperature and precipitation potential. We’ll learn how this may impact the current drought in Texas. And we’ll see if the hurricane season can offer any assistance.

  5. Objectives At the completion of this course of instruction you will: • Be familiar with the hottest summer on record for the state of Texas • Know which ocean the ERCOT meteorologist monitors most for potential influence of the Texas weather pattern • Be able to identify the historical year that is being applied as the primary historical match (analog) for the summer of 2015 • Know the probability of summer 2015 being hotter than normal • Recognize the total combined number of tropical storms and hurricanes (named storms) expected in the Gulf of Mexico in 2015

  6. Summer 2015 temperature outlook

  7. Repeat of 2011? Summer 2011 86.8° (Jun-Aug) Summer 1998 84.2° 2.6 degree difference Same difference as 2nd to 55th (1998 to 1929)

  8. Past Six Summers 2013: 21st hottest, 81.2° 2012: 13th hottest, 81.5° 2010: 11th hottest, 81.6° 2009: 29th hottest, 80.8° 2014: 50th hottest, 80.4° 2011: 1st hottest, 84.6° (POR 1895-current, Jun-Sep; all of Texas)

  9. Warming trend from the West over the past several seasons Positive (warm) phase of the Pacific Decadal Oscillation (PDO) has played a significant role. The Pacific Ocean is the primary driver of Texas weather patterns.

  10. Building the Forecast • Winter temperature and precipitation patterns • Winter upper level steering currents • Winter sea surface temperature pattern • El Niño Southern Oscillation (ENSO) • PDO, AMO, PNA, WPO, EPO • Drought

  11. Winter of 2014-15 69thColdest Winter on Record in Texas (1895-current) 69thDriest Winter on Record in Texas

  12. ENSO

  13. All 2/12/15 ENSO/200/ SST Building the forecast 200mb SST 2003, 1994, 2005 1987, 1977 1978, 1959 PDO

  14. Building the forecast PDO-AMO (was best for winter 2014-15)

  15. Top Historical Matches Summer 2015 2003 1977 1994 1988 1959 2005

  16. Summer Temperatures 2003 is being applied as the best historical match Latest set of historical years (as of 3/26/15)

  17. Summer Temperatures Last Year (for review) 10yr 30yr

  18. Summer Temperatures Summer 2015 Preliminary temperatures (2/27/15)

  19. Summer 2014 Temperatures Last Year (for review) 10yr

  20. Summer 2015 Temperatures Probabilities of an overall: Hotterthan normal summer: 20% Near normal summer: 35% Cooler than normal summer: 45% Continue to rely on a pattern, which has set up long-term. Hot West, mild East. Unlikely to rank with the summers of 2010-2013 for heat

  21. Summer Temperatures By month Best opportunity to break into a hotter pattern will be in September

  22. What Others Are Saying

  23. Summer 2014 Precipitation outlook

  24. Past Six Summers 2014: 65th driest, 10.93” 2011: 1st driest, 3.60” 2013: 64th driest, 10.89” 2012: 52nd driest, 10.35” 2010: 105th driest, 13.49” 2009: 60th driest, 10.78” (POR 1895-current, Jun-Sep; all of Texas)

  25. Top Historical Matches 1977 2003 1994 2005 1988 1959

  26. Summer Precipitation 2003 is preferred

  27. Summer Precipitation Summer Precip 2015 (2/27/15)

  28. Summer Precipitation Similar to last summer; Possibly a bit wetter 80-120% Near normal

  29. Summer 2014 drought outlook

  30. Drought Texas Reservoirs at 70.5% (Apr 14)

  31. Drought 35.5% 2014-04-07 36.4%, 2015-04-14 628.5 of 681ft

  32. Drought

  33. Drought

  34. Drought

  35. Drought

  36. Drought 80-120% Near normal

  37. Summer (and Fall) 2014 HURRICANE OUTLOOK

  38. Hurricane Forecast Historical Averages Named Storms: 12 Hurricanes: 6 Major Hurricanes: 3

  39. Hurricane Forecast

  40. Hurricane Forecast ENSO is a strong factor in determining the Hurricane season (number and intensities). Will the current weak El Niño continue Into the hurricane season?

  41. Hurricane Forecast Factors in Determining Numbers and Intensities ENSO Saharan Dust Dry Air Vertical Wind Shear Ocean Temperatures

  42. Hurricane Forecast What happened last year? MDA/EarthSat: 12/6/2 NOAA: 8-13/3-6/1-2 Colorado State University: 9/3/1* WSI/TWC: 11/5/2 ERCOT: 9/5/2 2014 Actual: 8/6/2 Normal: 12/6/3 *increased with a July update

  43. Hurricane Forecast 12 6 3

  44. Hurricane Forecast Total Named Storms: 11 Total Hurricanes: 6 Major Hurricanes: 2 Near normal but a bit more active than 2014 – Especially in the Gulf of Mexico Named Storms in Gulf: 4-5 Named Storms in Western Gulf: 2-3 Hurricane in Gulf: 1-2 Major Hurricane in Gulf: 0-1 Named Storms with Texas Landfall: 0 or 1 Hurricanes with Texas Landfall: 0 or 1

  45. Long-Term Historical Trends

  46. 6 of the hottest 21 summers on record (1895-current) in Texas have occurred since 2000. • 2011 (1) • 2012 (9) • 2009 (13) • 2001 (15) • 2010 (18) • 2006 (21) However … 5 of the hottest 21 (6 of 22, and 5 of the top 12) summers on record in Texas occurred in the 1950s. 19 of the 30 hottest summers on record occurred prior to 1960. 2014 2011

  47. Of the driest one-third of years since 1895, 15 of them have occurred since 1955. 25 occurred prior to 1955. The 1950s had the most dry years (6) followed by the 1930s, 20s, and 10s. Of the wettest one-third of years since 1895, 23 of them have occurred since 1955. 17 occurred prior to 1955. 2015 2011

  48. Between 1998 and 2013 (PDO-), an average of 16/8/3. Between 1976 and 1997 (PDO+), an average of 10/5/2. Between 1943 and 1975 (PDO-), an average of 10/6/3. 2013 and 2014 combined had fewer hurricanes and tropical storms than 2012. Quietest back-to-back years since 1993-1994.

  49. Summary • 80% likelihood of either normal or below normal temperatures for the summer as a whole, continuing a trend that began in the autumn of 2013 • Improvements to the drought may be limited. Likely still an issue for portions of Texas following the summer season, but not expecting deteriorating conditions • Hurricane season holds a bit more potential than the previous two years – but should El Niño hold, that could hamper the potential

  50. Questions ? ?

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