Winter/Spring Outlook: 2018 - 2019 ALBL 78th Annual Meeting New Orleans 5 December 2018 Jay Grymes WAFB Chief Meteorologist LSU AgCenter Climatologist

Annual Precipitation Trends: since 1900 USGCRP (2017): NCA4 Climate Science Special Report

LOUISIANA STATEWIDE AVERAGE RAINFALL

Seasonal Precipitation Trends: since 1900 USGCRP (2017): NCA4 Climate Science Special Report

VERY WET VERY WET VERY WET VERY WET VERY DRY

U.S. Drought Monitor: 29 November None D2 – Severe Drought D0 – Abnormally Dry D3 – Extreme Drought D1 – Moderate Drought D1 – Exceptional Drought

These are “climatological outlooks” … not “weather forecasts” NWS Climate Prediction Center “Monthly Outlooks” These are “climatological outlooks” … not “weather forecasts” They present the “best scientific guess” for averages of temperature & precipitation … … they do NOT provide guidance with respect to extreme weather events.

Temperature: December ~40% Above-Normal 33% Near-Normal ~27% Below-Normal ~35% to 45% chance that monthly average temperatures across Louisiana will be “significantly” above normal

Rainfall: December ~50% Above-Normal 33% Near-Normal ~17% Below-Normal ~45% to 55% chance that monthly total rainfall across Louisiana will be “significantly” above normal

“Near-normal” to “Wet” Temperature: Jan-Feb-Mar “EC” – Equal Chances No Tendency Rainfall: Jan-Feb-Mar “Near-normal” to “Wet”

Temperature: Jan-Feb-Mar “EC” – No tendencies No ‘hints’ as to monthly average temperature tendencies for Louisiana for the period

Rainfall: Jan-Feb-Mar ~40% Above-Normal 33% Near-Normal ~27% Below-Normal ~35% to 45% chance that monthly total rainfall across Louisiana will be “significantly” above normal

Rainfall: Jan-Feb-Mar Locally, a “wet” leaning outlook . . . . . . but a “dry” leaning outlook for the Ohio Basin is potentially good news for the Lower Mississippi

ENSO – El Niño / Southern Oscillation -- Ocean-Atmosphere linkage that produces “shifts” in regional / global weather and climate patterns . . . teleconnections El Niño / La Niña: ocean temperature (SST) ‘signature’ Southern Oscillation: atmosphere pressure- pattern ‘signature’

El Niño ‘signature’ along Gulf Coast: ‘Active’ Sub-Tropical Jet - ’Rainmaker’ Sub-Tropical Jet More Frequent Gulf Lows “Warm” SSTs

La Niña ’signature’ along Gulf Coast: ‘Less Persistent’ Winter Sub-Tropical Jet Fewer Gulf Lows “Cool” SSTs

Pacific Sea-Surface Temps (SSTs) El Niño on the way? Region of “warm” SSTs El Niño on the way?

ENSO – El Niño / Southern Oscillation El Niño – “warm” phase … ~25% of time La Niña – “cool” phase … ~ 25% of time La Nada – “near normal” El Niño La Niña

El Niño Median Rainfall: La Niña Median Rainfall: November thru March El Niño in Winter/Spring: “wet” Gulf Coast La Niña Median Rainfall: November thru March La Niña in Winter/Spring: “dry” Gulf Coast

Average January - April Rainfall El Niño vs. non-El Niño periods

Average January - April Rainfall El Niño vs. non-El Niño periods

Average January - April Rainfall Southeast Louisiana

ENSO and Bayou State Rainfall Solid relationships between South Louisiana rain during winter and spring, but weak link for the northern parishes ENSO can serve as a predictor (“Guidance”) for South LA rainfall for at least part of the year

WAFB Chief Meteorologist LSU AgCenter Climatologist (Ret.) “Thank You!” Jay Grymes WAFB Chief Meteorologist LSU AgCenter Climatologist (Ret.) jgrymes@wafb.com jgrymes@lsu.edu 225 / 215 - 4713

This does NOT mean that $LOSSES are declining! CAREFUL! This does NOT mean that $LOSSES are declining!