1. John Lewis, Senior Forecaster National Weather Service
The Year 2018/
A Look Ahead
John Lewis, Senior Forecaster
National Weather Service
Little Rock, Arkansas

2. Summer Forecast
Temperature

3. Three Month Rain
August – October, 2018

4. Soil Moisture Change
April 30 – July 24, 2018

5. Recent Email Input from a climatologist to the drought monitor…
“While the recent rains have been welcome, as the enclosed figure from WFO Little Rock indicates, when it comes to agriculture, timing is everything.”

6. 2018 Trends Through November Avg. Temperatures Precipitation
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
-3.7
+2.7
+2.6
-5.3
+6.3
+3.5
+1.4
-0.5
+2.3
+0.7
-4.8
Precipitation
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
-1.33
+8.12
+0.66
+0.02
-1.87
-1.13
-0.47
+3.14
+1.62
+1.57
+0.80
Through November, temperatures were 0.5 degree above average and precipitation was inches above average.

7. ENSO
Through Summer, 2019
El Niño
La Niña

8. Long Range Models Dec, 2018 – Feb, 2019 NMME Jamstek
Similar features in both models, including warmer than normal water along the equator (El Niño).

9. Energized Subtropical
Textbook El Niño
Winter
Polar Jet
Energized Subtropical
Jet

10. Different El Niños Winter
Super El Niños (Strong) in Eastern Pacific: Best chance of flame throwing warm winter across a large part of the country.
Modoki El Niño (Weak) in Central Pacific: Warmth scaled back (to west) with best chance of Arctic intrusions across a large part of the country (mainly east of the Rockies).

11. Weak/Moderate El Niño Winter Temperatures
At/below normal temperatures (in blue) have been common east of the Rockies.

12. Weak/Moderate El Niño Winter Precipitation
At/below precipitation (in yellow/orange) has been common except along the Gulf Coast.

13. Sunspots Declining
2009/2010
-4.3°F

14. Low Sunspot Pattern
When sunspots are low, 500 millibar heights seem to increase near Greenland (high pressure). This blocking pattern makes cold air dive southward.

15. Arctic Oscillation (AO)
Negative Phase

16. Arctic Oscillation (AO)
Negative Phase

17. Arctic Oscillation (AO)
Negative Phase

18. Arctic Oscillation (AO)
Negative Phase
It’s supposed to be mild across the south given La Niña conditions (early 2011), but a strongly negative AO took over and it became cold and snowy in January/February.

19. Winter Forecast (CPC)
Temperature

20. Winter Forecast (CPC)
Precipitation

21. Changes to Forecast?
Agree with highest confidence in a warmer than normal winter in the Pacific Northwest, and wetter than normal conditions in FL/GA.
Look for blocking at times to the north (negative phases of EPO/AO/NAO), with more shots of cold air than usual given a weak Modoki El Niño and lack of sunspots. This should result in below average temperatures locally.
Amount of precipitation depends on frequency of cold air. Would think above average given trends, with less liquid if Canada visits often.

22. On the Web

23. A Few Words
The authors found that if greenhouse gas emissions continue at the current rate, the atmosphere will warm up by as much as 2.7 degrees Fahrenheit (1.5 degrees Celsius) above preindustrial levels by 2040, inundating coastlines and intensifying droughts and poverty.

24. A Few Words
The frequency and intensity of extreme heat and heavy precipitation events are increasing in most continental regions of the world. These trends are consistent with expected physical responses to a warming climate.

25. A Few Words In Arkansas (last 20 years/data since 1895)…
Three top 15 hot years (2012, 2016, 2017)
Three top 15 dry years (2005, 2010, 2012)
Three top 15 wet years (2008, 2009, 2015)
Three busiest tornado years (1999, 2008, 2011)
Longest tornado (2008)
Deadliest flood (2010)
Largest hail (2006)

26. The End
Thanks for coming!
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