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

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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.

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.

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

TEMPERATURE OUTLOOK Summer 2015

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

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

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.

Building the Forecast 1.Winter temperature and precipitation patterns 2. Winter upper level steering currents 3. Winter sea surface temperature pattern 4.El Niño Southern Oscillation (ENSO) 5. PDO, AMO, PNA, WPO, EPO 6. Drought

Winter of th Coldest Winter on Record in Texas (1895-current) 69 th Driest Winter on Record in Texas

ENSO

200mb SST All 2/12/15 ENSO/200/ SST 2003, 1994, , , 1959 PDO Building the forecast

PDO-AMO (was best for winter ) Building the forecast

Top Historical Matches Summer 2015

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

Summer Temperatures Last Year (for review) 10yr30yr

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

Summer 2014 Temperatures Last Year (for review) 10yr

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

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

What Others Are Saying

PRECIPITATION OUTLOOK Summer 2014

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

Top Historical Matches

Summer Precipitation 2003 is preferred

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

Summer Precipitation % Near normal Similar to last summer; Possibly a bit wetter

DROUGHT OUTLOOK Summer 2014

Drought Texas Reservoirs at 70.5% (Apr 14)

Drought 35.5% %, of 681ft

Drought

80-120% Near normal

HURRICANE OUTLOOK Summer (and Fall) 2014

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

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?

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

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/ Actual: 8/6/2 Normal: 12/6/3 *increased with a July update

Hurricane Forecast

Hurricane Forecast Total Named Storms: 11 Total Hurricanes: 6 Major Hurricanes: 2 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 Near normal but a bit more active than 2014 – Especially in the Gulf of Mexico

TRENDS Long-Term Historical

of the hottest 21 summers on record (1895-current) in Texas have occurred since (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.

Of the driest one-third of years since 1895, 15 of them have occurred since occurred prior to 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 occurred prior to 1955.

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/ and 2014 combined had fewer hurricanes and tropical storms than Quietest back-to-back years since

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

Questions ? ? ? ?

51 1.______ was the hottest summer on record for Texas. a)2009 b)2010 c)2011 d)2012

52 2.Which ocean has shown the best correlation to Texas weather patterns? a)Atlantic b)Indian c)Pacific d)Saturn

53 3.The historical year that is being applied as the primary historical match for the Summer 2015 is______? a)2002 b)2003 c)2004 d)2005

54 4.Percentage probability for the summer of 2015 to be hotter than normal: ____? a)10% b)20% c)35% d)45%

55 5.The number of named storms forecasted in the Gulf of Mexico for 2015 are _______? a)0-1 b)2-3 c)4-5