John Lewis, Senior Forecaster National Weather Service The Year 2018/ A Look Ahead John Lewis, Senior Forecaster National Weather Service Little Rock, Arkansas john.lewis@noaa.gov

Summer Forecast Temperature

Three Month Rain August – October, 2018

Soil Moisture Change April 30 – July 24, 2018

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.”

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 11.30 inches above average.

ENSO Through Summer, 2019 El Niño La Niña

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

Energized Subtropical Textbook El Niño Winter Polar Jet Energized Subtropical Jet

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).

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

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

Sunspots Declining 2009/2010 -4.3°F

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.

Arctic Oscillation (AO) Negative Phase

Arctic Oscillation (AO) Negative Phase

Arctic Oscillation (AO) Negative Phase

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.

Winter Forecast (CPC) Temperature

Winter Forecast (CPC) Precipitation

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.

On the Web https://www.weather.gov/lzk

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.

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.

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)

The End Thanks for coming! Send to: john.lewis@noaa.gov