winter outlook (2012-2013) oregon museum of science and industry ams oregon chapter meeting 17...
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Winter Outlook (2012-2013)Winter Outlook (2012-2013)
Oregon Museum of Science and Industry AMS Oregon Chapter Meeting
17 November 2012
Oregon Museum of Science and Industry AMS Oregon Chapter Meeting
17 November 2012
Clinton RockeyNOAA/National Weather Service
El Niño vs. La Niña
• La Niña • Below-normal sea
surface temperatures in equatorial Pacific Ocean
• El Niño • Above-normal sea surface
temperatures in equatorial Pacific Ocean
Nov 1997
Feb 1999
El Niño vs. La Niña
La Niña
El Niño
La Niña vs El Niño
Precipitation
La Niña
Temperature
La Niña
El Niño
Temperature
El Niño
Precipitation
Based on 1950-2010 NOAA data
Current ENSO StatusCurrent ENSO Status
Tropical conditions may resemble a weak El Niño at times, but ENSO-neutral conditions will persist into 2013.
As of 8 November Warm Neutral
Sea Surface Temperatures (SST)Sea Surface Temperatures (SST)
• SST have decreased since July
• But rose slightly in October
Climate Model PredictionsClimate Model PredictionsENSO-neutral conditions favored through Spring 2013.
El Niño
La Niña
ENSO-neutral
Temperature Precipitation
NOAA’s U. S. Seasonal OutlooksDecember 2012 – February 2013
Favors Warmer
Favors Drier
Favors Wetter
Favors Cooler
Monthly Precipitation at PDXMonthly Precipitation at PDX
But Likely to FinishWetter than Average
Near Average Rainfall in most of Winter
ENSO Rain Signal ENSO Rain Signal
Portland Salem Eugene Astoria
-3.0
-2.0
-1.0
0.0
1.0
2.0
3.0
4.0
5.0
6.0
Winter* Rainfall : Departure from Average
El Niño La Niña Neutral Warm Neutral
33.12 45.6028.3224.76
* 15 October through 15 March
-4.0 0.0 4.0-3
0
3
ENSO/ONI vs PDOJan 1950 - Sep 2012
All Months/Years PQR Flood Events
PDO
EN
SO
/ON
IENSO and Flood EventsENSO and Flood Events
-4.0 0.0 4.0-3
0
3
ENSO/ONI vs PDOJan 1950 - Sep 2012
All Months/YearsPQR Major Flood Events (>=20 floods)
PDO
EN
SO
/ON
I
Portland Snow DataIn ‘Warm Neutral’ Years
Portland Snow DataIn ‘Warm Neutral’ Years
Average Portland Winter Snowfall ~5.0 inches
1993-94 (2.6”)
1990-91 (1.9”)1979-80 (12.4”)
2003-04 (12.3”)
1958-59 (2.9”)1960-61 (0”)
1989-90 (8.3”)
1992-93 (14.1”)
1952-53 (0.6”)
Portland Salem Eugene Astoria0
1
2
3
4
5
6
7
8
9
10
Winter Season Snowfall
AverageEl NiñoLa NiñaNeutralWarm Neutral
ENSO Lowlands Snow SignalENSO Lowlands Snow Signal
Portland Snowfall HistoryPortland Snowfall History
Top 10 snowiest winters:
34.0” 1968-69 El Niño24.2” 2008-09 ENSO Neutral22.4” 1955-56 La Niña20.3” 1959-60 ENSO Neutral17.4” 1992-93 ENSO Neutral16.3” 1979-80 ENSO Neutral14.7” 1970-71 La Niña13.4” 1964-65 ENSO Neutral12.3” 2003-04 ENSO Neutral12.0” 1994-95 El Niño10.5” 1953-54 ENSO Neutral
60% were ENSO Neutral20% were La Niña 20% were El Niño
1950-2011 data
PDX Snowfall History 1951 to 2010PDX Snowfall History 1951 to 2010
18 snow-shutout winters:(Trace or 0 snowfall)
8 were El Niño winters7 were ENSO Neutral winters3 were La Niña winter
So…in recent years, for low elevations, ENSO Neutral: - Wide Range of possibilities.
* Can have a moderately snowy winter (2003-04)* Can be very mild (1992-93 and 2001-02)
44% were El Niño (25% total of all winters)39% were ENSO Neutral (48% total of all winters)
17% were La Niña (27% total of all winters)
ENSO and Portland Snow EventsENSO and Portland Snow Events
-4.0 0.0 4.0-3
0
3
ENSO/ONI vs PDO1950 - 1995
All Winter Months (Oct-Mar) PDX Monthly Snowfall >= 2.0"
PDO
EN
SO
/ON
I
-4.0 0.0 4.0-3
-2
-1
0
1
2
3
ENSO/ONI vs PDO1950 - 1995
All Winter Months (Oct-Mar) PDX Monthly Snowfall >=10.0"
PDO
EN
SO
/ON
I
So, will there be a lot of rain or snow this
Winter?
Cartoon used with permission by T. McCracken
Winter 2012-13 OutlookWinter 2012-13 Outlook
TemperaturesNear average.
PrecipitationSlightly drier than AverageFebruary may trend to slightly wetter than average.
Lowland Snow PotentialLow to Moderate in January and February.More likely would be a Mixed Precipitation Event
(Sleet, Snow and/or Freezing Rain)
But…. Weather in ENSO Neutral years is Highly Variable.
Will we be shut out, or shut in due to snow?
POC: Clinton Rockey, NWS [email protected]
503.326.2340 x242
or
POC: Tyree Wilde, NWS [email protected]
503.326.2340 x223
Questions?