18 mar 2021 · The latest (Dec 2020 – Feb Precipitation should be mostly near average, with the best chances for above-average April 2021 Forecast
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[PDF] Water Supply Outlook National Weather Service Portland OR 400
3 mar 2021 · The next update to this outlook will be issued by April 7, 2021 Precipitation for the 2021 water year thus far (Oct 1, 2020 through March 2,
[PDF] Seasonal Climate Forecast: April-June 2021
18 mar 2021 · The latest (Dec 2020 – Feb Precipitation should be mostly near average, with the best chances for above-average April 2021 Forecast
[PDF] Oregon Climate and Health Report - State of Oregon
1 déc 2020 · During the wildfire events of September 2020, Oregon reached More precipitation will fall as rain rather than snow and in heavier rainfall events, African American buyers in Portland's Malo S Cool US cities prepare as future ' havens' for climate migrants Reuters 2019 April 6 [cited 2020 Nov 19]
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945
evolved into
is the only analog that developed into an
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Seasonal Climate Forecast
JulySeptember 2023
Issued: June 15, 2023
Contact: ODF Lead Meteorologist Pete Parsons
503945
7448 or
peter.gj.parsons@odf.oregon.gov ODA production support: Diana Walker; Andy Zimmerman; Jenn AmbroseODF production support: Julie
Vondrachek;
Kristin Cody
Sea Surface Temperatures (SSTs)
Animated
(PowerPoint only)SSTs (top) / Anomalies (bottom)
Courtesy:
ENSO neutral has transitioned intoEl Niño
El Niño Southern Oscillation (ENSO)
Current Status and Forecast
n The May Southern Oscillation Index (SOI) dropped to 1.0 , reflecting a weakening of the easterly trade winds across the tropical Pacific Ocean, corresponding with a transition toEl Niño
nThe Mar.
May 2023 Oceanic Niño Index (ONI
+0.1 C ) was still in the ENSO neutral range, but this index lags the real time sea surface temperatures (SSTs), which have warmed intoEl Niño
territory. n NOAA's Climate Prediction Center (CPC) has issued anEl Niño
Advisory.
They expect
El Niño
conditions to gradually strengthen... Important Note: This "Seasonal Climate Forecast" does not consider NOAA's ENSO forecast. It uses only historical and current ENSO conditions to find "analog years" that mostclosely match the evolution of the current ENSO state.https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf
ENSO-Neutral
Southern Oscillation Index (SOI)El NiñoLa Niña(1971-1972; 2000-2001; 2011-2012)May SOI
analogs all represented ENSO neutral conditionsMay 2023 SOI
1.0) dropped intoEl Niño
territoryStrongModerateENSO-NeutralEl Niño
Oceanic Niño Index (ONI)(1971-1972; 2000-2001; 2011-2012)La NiñaWeakStrongModerate
Mar. MayONI analogs
spanned the ENSO neutral rangeWeak Mar. May2023 ONI
(+0.1 C) reflected ENSO neutral conditionsEl Niño
vsLa Niña
(SST Patters in the Tropical Pacific Ocean) Courtesy: https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensocycle/ensocycle.shtmlJan. 2022 PDO
not availableNorth Pacific Ocean
(Poleward of 20N Latitude)Cool Phase
May 2023
PDO 2.36) was deeply in "Cool Phase"(1971-1972; 2000-2001; 2011-2012)May PDO
analogs were all in the "Cool Phase"Warm PhaseNeutralThe Pacific Decadal Oscillation (PDO)
(Reflects SST "Phase" in the North Pacific Ocean )Positive (Warm)
"Phase"Negative (Cool)
"Phase" Courtesy: http://research.jisao.washington.edu/pdo/img/pdo_warm_cool.jpgSST AnomaliesSST Anomalies Comparison
May Analogs
May 2023
n The May analog composite (left) has a similar SST anomaly pattern ("fair" match), compared to that of May 2023 (right). nThe analogs reflect waning
ENSO neutral conditions, but the current chart shows a developingEl Niño
...both display "cool phase" PDOGlobal Temperature Changes
Increase Error in Analog Forecasts!
July 2023 ForecastMean Upper-Air PatternUpper-Air Anomalies n Upper air patterns becoming less amplified than they have been... n None of the analogs predict "extreme" departures from average upper air conditions.July 2023 ForecastTemperaturesPrecipitation
n Temperatures near average with no prolonged hot spells indicted. n Precipitation near or slightly below average, in what is typically the driest month of the year, climatologically. August 2023 ForecastMean Upper-Air PatternUpper-Air Anomalies n Analogs are indicating the likelihood of anomalous troughing in the Gulf of Alaska with ridging centered over the Rockies. n More ridging and stronger SW flow aloft than normal over Oregon.August 2023 ForecastTemperaturesPrecipitation
n August appears to have the best chances for excessive heat. 1972 &2012 both had hot spells with NW valley temperatures over 100
F. n Below average precipitation but little change in drought status, sinceAugust is typically a very dry month.
September 2023 ForecastMean Upper-Air PatternUpper-Air Anomalies n Analogs diverge with 1972 showing strong troughing over Oregon, while 2001 and 2012 favor various degrees of anomalous ridging. nAnalog blend shows near
average upper air patterns, but don't count of it! Highly anomalous conditions in either direction are possible...September 2023 ForecastTemperaturesPrecipitation
n Graphics show a blend of a cold and wet 1972 countered by very warm and dry 2001 and 2012 analogs. n Forecast confidence is extremely low. Due to the evolvingEl Niño
1972 may end up being the best analog, so watch out for cold and wet!
July September 2023 ForecastMean Upper-Air PatternUpper-Air Anomalies nMore upper
level troughing than average over Oregon early in the summer gets mostly balanced by anomalous ridging in August. n Analogs diverge significantly by September...1972 developedEl Niño
conditions, but the others didn't. Stay tuned for significant updates... JulySeptember 2023 ForecastTemperaturesPrecipitation
n Temperatures generally above average, especially in August. September is a wildcard and may turn out much cooler than currently predicted. n Drier than normal conditions in July and August. Low confidence in the September rainfall forecast, which could go either way...Forecast Highlights
n Central and eastern Tropical Pacific Ocean temperatures have recently warmed from ENSO neutral intoEl Niño
status. NOAA's Climate Prediction Center (CPC) expects further strengthening ofEl Niño
nOf the analog years used to create this forecast
(1972; 2001; 2012 only 1972evolved into
El Niño
. The other analogs will likely need to be updated for the next forecast... nThe highly anomalous weather (a
La Niña
signature) that we have been experiencing should moderate, but the current analogs all had a very warm August. nLow confidence in the current September forecast.
1972is the only analog that developed into an
El Niño
, and it had a cold and wet September. The other analogs skew the current forecast warm & dry.Disclaimer: This forecast is not associated with NOAA's CPC (see "Forecasting Methods..." at: https://oda.direct/Weather
) nor the official CPC "Three