and Summer in Central TX Aaron Treadway Meteorologist National - - PowerPoint PPT Presentation

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and Summer in Central TX Aaron Treadway Meteorologist National - - PowerPoint PPT Presentation

Mar 19, 2023 25 likes •487 views

Weather Outlook for Spring and Summer in Central TX Aaron Treadway Meteorologist National Weather Service Austin/San Antonio Outline A Look Back At 2014 Spring 2015 So Far El Nio Update Climate Prediction Center Outlooks

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Weather Outlook for Spring and Summer in Central TX

Aaron Treadway Meteorologist National Weather Service Austin/San Antonio

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Outline

  • A Look Back At 2014
  • Spring 2015 So Far
  • El Niño Update
  • Climate Prediction Center Outlooks
  • 2015 Atlantic Hurricane Season
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Austin Mabry & Bergstrom

  • Bergstrom went 41 days without rain (7/25-9/3)
  • 7th longest period since 1942 (record: 64 days in 1993)
  • Camp Mabry was only climate site that had above normal rain due

to heavy rain event night of 7/17-7/18 (over 5”)

  • Over half of our rainfall in 2014 at both Camp Mabry and Bergstrom
  • ccurred in five events lasting 3 days or less!

Austin Mabry:

  • 1. 5.36” (7/16-7/18)
  • 2. 4.14” (9/17-9/19)
  • 3. 3.67” (11/20-11/22)
  • 4. 3.53” (5/12-5/14)
  • 5. 2.11” (11/4-11/6)

18.81” of 35.53” (52.9%)

Austin Bergstrom:

  • 1. 4.34” (5/12-5/14)
  • 2. 3.72” (11/20-11/22)
  • 3. 3.05” (5/27-5/28)
  • 4. 2.85” (11/4-11/6)
  • 5. 2.05” (9/17-9/19)

15.99” of 29.47” (54.3%)

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Location Average Temp Normals Difference Austin Bergstrom 66.9° 67.2°

  • 0.3°

Austin Mabry 69.0° 69.3°

  • 0.3°

San Antonio 70.4° 69.4° +1.0° Del Rio 70.9° 70.5° +0.4° Location Average Max Temp Normal Max Temp Difference Austin Bergstrom 79.2° 79.7°

  • 0.5°

Austin Mabry 79.2° 79.7°

  • 0.1°

San Antonio 81.1° 80.2° +0.9° Del Rio 82.1° 81.6° +0.5° Location Average Min Temp Normal Min Temp Difference Austin Bergstrom 54.7° 54.8°

  • 0.1°

Austin Mabry 58.3° 58.9°

  • 0.6°

San Antonio 59.7° 58.6° +1.1° Del Rio 59.8° 59.2° +0.6°

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2014 – 36th Warmest 75th Coldest 2014 – 55th Warmest 6th Coldest

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2014 Drought Monitor

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Flash Flooding

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2015 Climographs

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2015 Precipitation So Far

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Current Drought Monitor

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April 12th – April 19th

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Why may help be on the way?

El Niño Conditions La Niña Conditions

Latest Weekly SST Departures: 1.3oC 0.8oC 0.9oC 1.3oC

  • Warmer than normal sea surface temps (SSTs) in Pacific
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Oceanic Niño Index (ONI)

  • ONI is based on SST departures from average in

the Niñ0 3.4 region.

  • 3 Month running-mean SST departure
  • Definitions

– For El Niño: Positive ONI greater than or equal to +0.5ºC – For La Niña: Negative ONI less than or equal to -0.5ºC

0.9oC

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ONI Evolution Since 1950

El Niño La Niña

Neutral

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El Niño Conditions Present!

  • Approx. a 70% Chance that El Nino

Conditions will Continue through summer 2015, and a greater than 60% chance it will last through autumn.

Normal (“Neutral”) Conditions El Niño Conditions

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  • El Niňo typically causes subtropical jet to be active over southern

U.S. and polar jet to be displaced to the north

El Niño Winter “Teleconnections”

Subtropical jet

“Teleconnections” are statistical linkages between changes

  • ccurring in widely separated regions
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  • El Niňo typically causes South Central Texas to be wetter and cooler

than normal more than half of the time!

El Niño Winter “Teleconnections”

Subtropical jet

10-50% wetter than normal Trend Holds ~50% of the time 1-2oC cooler than normal Trend holds ~75% of the time

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El Niño Conditions Continue!

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El Niño 3.4 SST Model Outlook

Figure provided by the International Research Institute (IRI) for Climate and Society (updated 14 April 2015).

The majority of the models indicate Niño 3.4 SST anomalies will remain greater than or equal to +0.5C through the end

  • f 2015.
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The NCEP CFS.v2 ensemble mean (black dashed line) predicts El Niño through NDJ 2015-16.

El Niño Conditions Continue!

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6-10 Day Outlook

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8-14 Day Outlook

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May 2015

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May / June / July Outlook

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April Drought Outlook

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April 16th – July 31st Drought Outlook

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2014 Hurricane Outlook

Actual 8 6 2

MAY 8-13 3-6 1-2

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Named Hurricanes Major Average (1981-2010) 12.1 6.4 2.7 Record High 28 (2005) 15 (2005) 7 (2005) Record Low 4 (1983*) 2 (2013*) 0 (2013*) *Last Year this Occurred

Normal and Record Activity

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Tropical Storm Risk

ACE Major Hurricanes Hurricanes Tropical Storms December Forecast 79 (± 58) 2 (± 2) 6 (±3) 13(±4) April Forecast 56 2 5 11

  • Two Professors in the Department of Science and Climate Physics at University College

London, UK

  • ACE – Accumulated Cyclone Energy – wind energy index.
  • Reasons for Below Normal Season:
  • Suppression of trade winds over the Caribbean and North Atlantic
  • ENSO Neutral Conditions (not the current ENSO forecast)
  • They note high uncertainty in their trade winds and SST forecasts
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Colorado State University

Major Hurricanes Hurricanes Tropical Storms April Forecast 1 3 7

  • Philip J. Klotzbach and William M. Gray
  • “One of the least active seasons since the middle of the 20th Century”
  • Reasons For Forecast:
  • Moderate Strength El Niῆo
  • Negative Atlantic Multidecadal Oscillation (AMO)
  • Positive North Atlantic Oscillation (NAO)
  • Strong Atlantic Subtropical High & Strengthened Trade Winds
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NAO Hurricane Teleconnections

  • Subtropical high shifted to north and

east (hurricanes recurve farther east)

  • More East Coast landfalls (although

most out to sea)

NAO Negative Phase

Azores Iceland

  • Subtropical high shifted to south and

west (hurricanes blocked from recurving to the north)

  • More Gulf Coast landfalls

NAO Positive Phase

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  • A Decreased Number of Storms in the

Atlantic Basin

  • Storms affected by atmospheric circulation,

largely through the vertical wind shear profile.

– Increased vertical wind shear due to increases in westerly winds aloft.

El Niῆo Hurricane Teleconnections

http://www.aoml.noaa.gov/hrd/Landsea/lanina/

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El Niῆo Hurricane Teleconnections

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ENSO Hurricane Influence El Niño vs La Niña

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North Carolina State University

Major Hurricanes Hurricanes Named Storms April Forecast 1 3 6

  • Dr. Lian Xie, Professor of Marine, Earth and Atmospheric Sciences
  • “Significantly less active than the overall averages from 1950 to present”
  • “Evaluates more than 100 years of historical data on Atlantic Ocean hurricane positions

and intensity, as well as other variables including weather patterns and sea-surface temperatures, to predict how many storms will form in each ocean basin.”

  • Reminder that it only takes one landfalling storm to create loss of life and property…see

Hurricane Andrew (quiet 1992 Hurricane Season)

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Spotter Phone: 800-292-5508 Website: weather.gov/austin or mobile.weather.gov Facebook: NWSSanAntonio Twitter: @NWSSanAntonio