winter outlook (2012-2013) oregon museum of science and industry ams oregon chapter meeting 17...

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 Portlandclinton.rockey@noaa.gov

503.326.2340 x242

or

POC: Tyree Wilde, NWS Portlandtyree.wilde@noaa.gov

503.326.2340 x223

Questions?