Winter Outlook (2012-2013) Oregon Museum of Science and Industry AMS Oregon Chapter Meeting 17...
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Winter Outlook (2012-2013)Oregon Museum of Science and Industry AMS Oregon Chapter Meeting17 November 2012
Clinton RockeyNOAA/National Weather Service
1El Nio vs. La Nia La Nia Below-normal sea surface temperatures in equatorial Pacific Ocean El Nio Above-normal sea surface temperatures in equatorial Pacific Ocean
Nov 1997Feb 19992
El Nio vs. La NiaLa NiaEl Nio3
La Nia vs El NioPrecipitationLa NiaTemperatureLa Nia
Based on 1950-2010 NOAA data
4Current ENSO StatusTropical conditions may resemble a weak El Nio at times, but ENSO-neutral conditions will persist into 2013.
As of 8 November Warm Neutral5Sea Surface Temperatures (SST) SST have decreased since July But rose slightly in October
6Climate Model PredictionsENSO-neutral conditions favored through Spring 2013. El NioLa NiaENSO-neutral
TemperaturePrecipitationNOAAs U. S. Seasonal OutlooksDecember 2012 February 2013Favors WarmerFavors DrierFavors WetterFavors Cooler8Monthly Precipitation at PDX
But Likely to FinishWetter than AverageNear Average Rainfall in most of Winter ENSO Rain Signal * 15 October through 15 March10ENSO and Flood Events11Portland Snow DataIn Warm Neutral YearsAverage 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)12ENSO Lowlands Snow Signal
13Portland Snowfall HistoryTop 10 snowiest winters:
34.0 1968-69 El Nio24.2 2008-09 ENSO Neutral22.4 1955-56 La Nia20.3 1959-60 ENSO Neutral17.4 1992-93 ENSO Neutral16.3 1979-80 ENSO Neutral14.7 1970-71 La Nia13.4 1964-65 ENSO Neutral12.3 2003-04 ENSO Neutral12.0 1994-95 El Nio10.5 1953-54 ENSO Neutral60% were ENSO Neutral20% were La Nia 20% were El Nio1950-2011 data14PDX Snowfall History 1951 to 201018 snow-shutout winters:(Trace or 0 snowfall)
8 were El Nio winters7 were ENSO Neutral winters3 were La Nia winterSoin 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 Nio (25% total of all winters)39% were ENSO Neutral (48% total of all winters)17% were La Nia (27% total of all winters)15ENSO and Portland Snow Events16
So, will there be a lot of rain or snow this Winter?Cartoon used with permission by T. McCrackenWinter 2012-13 OutlookTemperaturesNear 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?18POC: Clinton Rockey, NWS Portlandclinton.firstname.lastname@example.org x242
POC: Tyree Wilde, NWS Portlandtyree.email@example.com x223