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2014 Spring/Summer Temperature and Precipitation Outlook for the Ark-La-Tex Region. Jason Hansford Senior Meteorologist National Weather Service Forecast Office Shreveport, LA.
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2014 Spring/Summer Temperature and Precipitation Outlook for the Ark-La-Tex Region Jason Hansford Senior Meteorologist National Weather Service Forecast Office Shreveport, LA
RECAP: These are the composite temperature/precipitation anomalies when neutral ENSO conditions are present throughout the year
Winter Precip. Breakdown December 2013 Monthly Precip. Departures December 2013 Observed Precip.
Winter/YTD Precip. Breakdown(through March 20th) Year-To-Date Observed Precip. Year-To-Date Percent of Normal Precip.
Seasonal Temp. Statistics * Ranked as the 8th coldest Winter on record (Records since 1930) ** Ranked as 5th coldest Winter on record (Records since 1908)
Seasonal Precip. Statistics * Ranked as the 5th wettest Fall on record (Records since 1871) ** Ranked as the 4th wettest Fall on record (Records since 1892) *** Ranked as the 6th driest Winter on record (Records since 1930) **** Ranked as the 2nd driest Winter on record (Records since 1902) ***** Ranked as the 5th driest Winter on record (Records since 1906)
Calculated Soil Moisture Soil Moisture is ~450-500 mm (17.7- 19.7 in.) deep. Deficits exist over North LA, Southern AR, and East TX.
U.S. Drought Monitor March 18, 2014
Hydrologic Drought(Lake Pool Stage as of 3/20/14) Bob Sandlin: 334.51 ft (-2.99 ft) Lake Fork: 398.81 ft (-4.19 ft) Toledo Bend: 170.01 ft (-1.99 ft) Sam Rayburn: 161.46 ft (-3.04 ft) All of these reservoirs except for Sam Rayburn are near/slightly higher than this time last year. Sam Rayburn is about one foot lower this year.
Regional Aquifer Status • Much of the rural areas of our region are served from underground aquifers for a source of water. The Carrizo-Wilcox and Sparta aquifers are the major aquifers that serve the region.
North Louisiana Aquifer Info.(through Feb. 2014) Data is taken from a number of wells throughout Caddo Parish, through collaboration between LSU-Shreveport (Red River Watershed Management Institute) and the Caddo Parish Groundwater Monitoring Project.
What Can We Expect from Temperatures/Precipitation this Fall and Winter??? • We must look at sustained temperature patterns in the Equatorial Pacific, stretching along the equator from 170W to 120W longitude, and 5N to 5S latitude. • Based on certain temperature patterns over a period of time, El Niño or La Niña episodes may develop, which will alter the path of the jet stream, and ultimately determines temperature and precipitation patterns all over the world.
What is El Niño? • Operational Definition: defined by a warming of Sea Surface Temperatures (SST’s) in the Equatorial Pacific. This phenomenon is characterized by a trend of the 3 month running mean of SST’s 0.5C above normal. • SST’s are measured across various regions in the Pacific, but the Niño 3.4 Region (5°N – 5°S and 170°-120°W) is what is particularly monitored for ENSO conditions. • To be classified as a distinct El Niño episode, these SST conditions must be met for a period of at least 5 consecutive months.
What is La Niña? • Operational Definition: defined by a cooling of Sea Surface Temperatures (SST’s) in the Equatorial Pacific. This phenomenon is characterized by a trend of the 3 month running mean of SST’s 0.5C below normal. • Just like El Niño, SST’s are measured across various regions in the Pacific, but the Niño 3.4 Region (5°N – 5°S and 170°-120°W) is what is particularly monitored for ENSO conditions. • To be classified as a distinct La Niña episode, these SST conditions must be met for a period of at least 5 consecutive months.
SST’s in the Equatorial Pacific Niño 3.4 Region: 5°N - 5°S and 170° - 120°W [ ] [ ]
How Strong will ENSO be this Spring? Strong El Niño Neutral Strong La Niña Model Forecasts
El Niño Conditions Developing • On March 6th, the Climate Prediction Center (CPC) issued an El Niño Watch for the tropical Pacific, meaning that conditions are favorable for the development of El Niño conditions within the next six months.
Low Confidence ENSO Forecast • Much of the SST data are taken from the Tropical Atmosphere Ocean Project, or TAO buoy array, which consists of 55 moored buoys that have been in place since the mid 1980’s along both sides of the equator in the tropical Pacific. • Due to budget cuts and other reasons, only about one-third of the buoys are now reporting on a daily basis, with the rest sending either no or partial data. In order to predict El Niño events, data from the surface down through the upper 1600 feet of water are needed. Source: http://mashable.com/2014/03/06/buoy-array-el-nino-forecasting/?utm_cid=mash-com-Tw-main-link
TAO Array Climate forecasters heavily rely on the TAO array, but do have access to other buoys that drift with the ocean currents, satellite imagery, and info. sent back from passing ships.
Should El Niño Develop late this Summer or Fall… • They will usually peak during the winter months (Dec-Feb). • They typically persist for 9-12 months, but could linger up to 2 years. • Could reduce the Atlantic hurricane activity, especially during the latter part of the season (if at all).
Arctic Oscillation • Refers to the atmospheric circulation pattern in the northern middle and high latitudes in the Arctic. These can generate strong shifts in the climate pattern than can overwhelm or amplify the typical El Niño/La Niña impacts. • Exhibits a negative phase when higher pressures develop over the Polar region, and low pressures develop in the mid- latitudes (near 45°N). This results in frigid air plunging south into North America east of the Rockies. • Exhibits a positive phase when lower pressures develop over the Polar region, and higher pressures develop in the mid- latitudes. This will keep the frigid air locked up in the Arctic region, but also drives ocean storms farther north. Thus, wetter weather is usually associated throughout Alaska, Scotland, and Scandinavia.
North Atlantic Oscillation • Fluctuations in the difference of sea-level pressure between the Icelandic Low and the Azores high. • + NAO prevents cold air from plunging southward over eastern North America. • Shows multi-decadal signal.
Monthly Observed Arctic and North Atlantic Oscillation Indices Negative phase Neutral phase
Assuming neutral conditions prior to El Niño (Based on Climo.) Mar. 2014 – May 2014
Spring Outlook Issued by the Climate Prediction Center
Summer Outlook Issued by the Climate Prediction Center
The End Any Questions???