1. 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

2. 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)

3. 2016
NWS Brownsville/Rio Grande Valley

4. 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, ???

5. Winter 2015/2016

6. Winter 2015/16: Forecast vs. Reality

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

8. 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

9. Spring 2016 – RGV Rain

10. Spring 2016: Occasionally Stormy
May 31, Hidalgo County

11. 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)

12. 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

13. Summer 2016

14. Summer 2016

15. 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

16. Autumn 2016

17. 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)

18. Autumn 2016 H

19. Autumn 2016 MB MA A

20. Persistently

21. Fluctuating Drought Conditions
Some Relief in November and This Past Weekend

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

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

24. 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?

25. North Atlantic Oscillation: What?

26. North Atlantic Oscillation: The Negative Phase

27. North Atlantic Oscillation: The Positive Phase

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

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

30. 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)

31. Winter 2010/2011

32. Snowpack…and NAO?

33. 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

34. 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

35. 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
(cell)
weather.gov/rgv
Event Summaries: weather.gov/rgv/events
Local Outlooks: weather.gov/rgv/outlooks