Rod's 2019-2020 Winter Outlook

The headline for this up-coming winter season is an 85% confidence from NOAA that an Enso Neutral weather pattern will hold through the winter months.  Since 1950, 16 Neutral winter seasons have been recorded and the average for Portland for the months of November through March are the following: 

Mean Temperature Average:  Near normal                                          

Total Precipitation:  22.22" /  below normal by 1.12"                              

Total Snowfall:  5.4"    


Fine tuning the above projection shows what I refer to as "positive tilt" in that NOAA's predicition shows slightly above normal Pacific water temperatures in the equatorial region used for seasonal forecast projection.  The positive projection falls short of a weak El Nino but can make a difference in weather patterns.  A "positive tilt" for our region leads to an increasing chance of drier than normal rainfall and higher than average snowfall. Temperature averages show near normal seasons or colder than normal, but indicate a low percentage chance for a warm winter season. 


Other trends I researched include winters following a cool, wet September and Neutral winters following weak El Ninos, which was the enso cycle last winter.  Both of the mentioned categories show zero matching patterns to reach a conclusion. 


Rod's WINTER OUTOOK 2019-2020 SEASON

PORTLAND TEMPERATURES:  NEAR NORMAL  +.5 degree departure                                                                                                                   (wildcard)  Watch for a cold January, possibly -3 to -6 degrees below normal.

PORTLAND PRECIPITATION:  DRIER THAN NORMAL / 79% of average, deficit of -4.95"

PORTLAND SNOWFALL:  8 -10" LIKELY / Possible early snow in November or December, but                                                                less than 3" through January 1st.  An 8" snow storm is possible in January or February. 

MT. HOOD SNOWPACK:  98% OF NORMAL 

Timberline:  600" or more

Meadows:  500" or more

Skibowl:  60" base or higher January, February and March

In general, good steady base building in December at 5,000 feet and higher, making for a good holiday break.  The above snowpack numbers would be at least 100" more of total snowfall than last winter and the best season in terms of total snow since 2016-2017 and the 2011-2012 season. There is every reason for skiers and boarders to expect a great season on the mountain.

-Meteorologist Rod Hill


It is worth checking my forecast results from October of 2018 for last winter.  Below is my Forecast Check:

1.  Portland Temperature Outlook, Nov - March Mean Temperature
 
Rod said 73% confidence of near normal to above temperatures
 
Verify:  Nearly exactly normal with a departure of  -.2 degrees below 30 year average
 
This is a forecast hit for near normal temperature average
 
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2.  Portland Total Precipitation Outlook, Nov-March
 
Rod said near normal to favoring below normal for the season
 
Verify:  Well below normal through January, then a wet February.  The five month total at PDX
was a deficit of -6.97”, or 70% of average.
 
This is a forecast hit  (only a significant wetter than normal average would have been a miss)
 
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3.  Portland Snowfall Outlook
 
Rod said no big storms of 8” or greater.  Total season snowfall less than 6.00 inches. 
 
Verify:  Zero snow through February 1st, then a season total of 7 inches.  Largest snowfall
was 4.9”  at PDX February 9th.  On the same day, downtown Portland picked up a dusting of snow.  Most of the metro valley (except east side) saw less than 3” of total snowfall for the season. 
 
This is a forecast hit
 
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4.  Valley Windstorm Threat Outlook
 
Rod said a heightened 40% of a 60 mph windstorm event. 
 
Verify:  On January 5th, a storm produces 3 hours of 40-60 mph south wind gusts.  PDX peaks at 54 mph, but Swan Island hits 60 mph and south of Salem in Turner, gusts peak at 62.  
 
This is a forecast hit
 
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5.  Mt. Hood Snowpack Outlook
 
Rod said 66% of average snowpack through April 30th, slightly below the winter of 2017-2018.
Mt Hood test site had 69% for the season.  
 
This is a forecast hit  (only missed the season total by 3%) 
 
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The above results show all five projections were within the bounds of correct category of departure and a good outlook!
 
My seasonal forecast accuracy dating back to the 2000-2001 winter season is 68.5%.  The percentage is well above industry standards closer to 55-60% for projecting below, normal or above normal departure categories. 
 
Rod Hill