Warm and Dry, With A Few “Wild Cards” A Review of 2016 (and a Preview of Winter 2017) for the Lower Rio Grande Valley Warm and Dry, With A Few “Wild Cards” Barry Goldsmith Warning Coordination Meteorologist With Erin Billings, Observation Program Leader National Weather Service Brownsville/Rio Grande Valley weather.gov/rgv

2016, In Review (so Far) Winter, Spring Summer: Warm/Dry January-February Wetter than Average March-June, Still Warm-Hot Record Hot, Relatively Dry late June-August This Was a Near-Perfect Setup for Some Crops (i.e., Cotton) into Summer The Record Heat Continued Right Through the Fall (September-November) Rainfall Was Mixed, but Mostly Dry Rankings: 5th Warmest, 37th Driest (through October) (Records Since 1895)

2016 NWS Brownsville/Rio Grande Valley

Winter 2015/2016 What Occurred Was Opposite of What Was Forecast More to the Story than El Niño! One Theory: Difference in Sea Surface Temperature Anomalies Between the Equatorial El Niño Region and Eastern Subtropical Pacific Led to the Warm/Dry Outcome Other Influences Fitting Together (++PDO, +NAO/AO, ???

Winter 2015/2016

Winter 2015/16: Forecast vs. Reality

Winter 2015/16: Sea Surface Temperature Anomalies Warm Water Warm Water El Niño Zone

Spring 2016 Better Rainfall in Central/East Texas; Mixed Bag for RGV but Relatively Wet (Still) More to the Story than El Niño! El Niño “Lag” Still Influenced Forecast (“Cooler”) Even Though Conditions Were Quickly Oscillating Back Toward Neutral

Spring 2016 – RGV Rain

Spring 2016: Occasionally Stormy May 31, Hidalgo County

Summer 2016 After a Wet (but Still Warm) June, “La Canícula” Reigned ENSO Rapidly Transitioning toward Weak La Niña RGV Rainfall Stopped at the End of June July/August: 4th Hottest on Records in RGV (since 1895); Warmest Since 2009 (#1)

Summer 2016 H “Earl” August 2-6 La Canícula Note that tropical weather was “closed” to Texas; only Earl was in the picture in early August and remained well south. La Canícula “Earl” August 2-6

Summer 2016

Summer 2016

Autumn 2016 Despite a Weak La Niña*, Quiet Tropics + Extended “La Canícula” Ensured a Dry Season, Especially September Record-Near Record Heat Continued: September-October: 2nd Hottest on Records in RGV (since 1895); Hottest Since 1900! (#1). 13th Driest, Also *Based on three 3-month ONI values below -0.5

Autumn 2016

Autumn 2016 November “Rallied” A Bit After September and October Brought the Return of Moderate to Severe Drought in Some Areas Main Rain Events Were Early (November 7-10) and Middle (November 18)

Autumn 2016 H

Autumn 2016 MB MA A

Persistently

Fluctuating Drought Conditions Some Relief in November and This Past Weekend

Winter 2016/17 Rainfall Outlook 33-39% 40-49%

Winter 2016/17 Temperature Outlook 33-39% 40-49% 60-69% 50-59%

The “Why” Behind the Outlook Weak La Niña Expected to Continue into Early Spring Continued Warm Subtropical Pacific Sea Surface Temperatures May Enhance Subtropical Eastern Pacific Ridge Wild Cards: Neutral Arctic/North Atlantic Oscillation (NAO) adds little Value but a period of -NAO could open the door to cold/freezes Wild Card: Pacific-Decadal Oscillation Index Has Slipped Toward Neutral As Well Wild Card: Siberian/Alaskan/NW Canadian Snow Pack: Assisting Arctic Outbreaks?

North Atlantic Oscillation: What?

North Atlantic Oscillation: The Negative Phase

North Atlantic Oscillation: The Positive Phase

North Atlantic Oscillation: Where We Are Now Recently Negative, But Generally in Neutral. Will Negative Trend Continue?

North Atlantic Oscillation: Where We May Be Going Generally Negative, But Only Slightly Unfortunately, NAO only has a 2-week prediction cycle

February 2-5 2011 Winter Blast Even in a “Warm and Dry” Winter, a Strongly Negative NAO May Have Helped Lead to This, When Combined with La Niña (Moderate in 2011)

Winter 2010/2011

Snowpack…and NAO?

What to Watch For This Winter Confidence is High for Warmer than Average Temperatures and Medium for Drier than Average Rainfall Average RGV Temps for the Season: Afternoon 73, Wake-Up 53 Average Rainfall for the Season: 3.5 to 5 inches Fronts Will Tend to Come Through With Little Rainfall… …But A Few Will Come as “Gray ‘Northers” Wild Card A: Puzzle Pieces (i.e. period of Negative NAO) and “Dry” Front Could Produce the First Valley- wide Notable Freeze in Several Years (Mid Dec through Mid Feb) Wild Card B: One or Two Texas Gulf Lows Could Bring Seasonal Rainfall to Near Average

Preparation Outlook Winter 2017, Rio Grande Valley Though Warmer and Drier is the Forecast, Your “Safety Margin” Potential Includes: One Valley-wide Freeze (minimum temperatures 27 to 31 degrees One or Two Decent Rain Events Can’t Rule out a Minor Ice Storm (2011, 2014, 2017??) Drought Degradation into the Lower RGV? Keep Watching the Trends. (Medium Confidence) Late-Season Wildfire Spread Potential if Severe Drought Develops Reason? More fronts should come through “dry” than “damp”, leading to potential for afternoons with 15+ mph wind and <15% relative humidity, especially in late winter

Thank You! weather.gov/rgv Event Summaries: weather.gov/rgv/events Contact: Barry S. Goldsmith National Weather Service Office 20 South Vermillion Road Brownsville, TX 78521 956-572-1492 (cell) barry.goldsmith@noaa.gov weather.gov/rgv Event Summaries: weather.gov/rgv/events Local Outlooks: weather.gov/rgv/outlooks