Rod's Weather Headlines

As promised the headline of this weekend's storm is the Mt. Hood snow, expected to be heavy through the day Monday, with snow showers continuing Tuesday.  Meadows and Timberline begin this evening with a foot on the ground and another 12" likely.  24-30" seems like a good guess for total snow through Tuesday morning! Government Camp had dropped to freezing late this afternoon and will see accumulating snow all night, 6-12" looks possible.  Travelers should prepare for winter driving through the day Tuesday.  

The surprise headline has been all of the lightning.  Numerous thunderstorms today from the coast to the Cascade foothills.  Storms have dumped heavy rain, small hail and gusty winds more than 40 mph.  Valley rain totals will approach 2.00" through noon Monday.  Thunderstorms look at least possible into the day Tuesday.  Remember if you hear thunder, lightning is close by.  

Forecast charts are hinting at very wet weather with a big storm or two, not this week, but the following week.  Looks like we are settling into active weather!

Today, Oct. 24, marks the first heavy snow on Mt. Hood this season.  Ski  resorts at 5,000 feet received 12" of snow.  The last La Nina season of 2007 had an earlier snowfall of 24" at Timberline and 26" at Meadows on Oct. 21st!  That fall went on to see 78" through Thanksgiving weekend, but periods of warm temperatures kept base amounts near two feet into the first week of December.  The La Nina season went on to record 791" at Timberline Lodge through the end of April!  Compare the total to last season's of 505 inches.  More evidence that this year's stronger La Nina could bring big snows to the mountain! Could we be looking at 800" or more on the mountain?

It is worth mentioning that the La Nina of 2007-2008 also recorded the record coast windstorm that had speeds and damage similar to a category three hurricane.  Also the Vernonia flood happened in December 2007.  

Forecast charts continue to show active weather the next two weeks.  

Here is your update to this weekend's weather:  High confidence that once the rain starts this evening, it will become heavy at times into Sunday morning.  Rain totals could reach an inch or more.  Winds southwest 15-35 mph will be breezy Saturday night through the day Sunday. Gusts of 40 will be possible as the front passes Portland Sunday morning.  Likely rain will continue through the day Monday.  High Wind Warning  issued for the coast Saturday evening through early Sunday.  Possible wind gusts near 60 mph.  A strong jet core continues to show up in the modeling, which will fuel the heavy rain.  Coast amounts could exceed 3.00 inches.  

Snow levels will likely be near 6,000 feet or higher Saturday and Sunday morning. Behind the cold front,   Sunday afternoon snow levels will fall to near pass level at 4500 feet and to 4,000 feet by Monday morning.  Sunday and Monday will likely produce the first snow of the season at Timberline Lodge and most Cascade passes.  Winter travel should be expected Sunday afternoon and into the day Tuesday.  Snow amounts near and above 5,000' Sunday evening through Monday could be 12-20 inches!  Government Camp depending on temperature will see 4-8" Sunday overnight, through the day Monday.  

Freezing temperatures in the out-lying metro areas, such as McMinnville, Hillsboro and Battle Ground were right on time this weekend.  Meaning, mid-October is considered average for our first fall dip.  The average first freeze at PDX is November 8th.  The earliest freeze at the airport is Oct. 8, 1985.  Way back in 1934, Portland never dipped to 32 degrees!  Last year, PDX did not cool to 32 degrees until the second day of December. 

I look for freezing spots again Monday and Tuesday morning.  We should start to warm up a bit Wednesday.  

Comet 103P/Hartley 2 is positioning itself for its closest approach to Earth on October 20, 2010.  This bring the comet nearer to Earth since its 1986 discovery, and makes it one of the nearest visits of any comet in the last few centuries.

For the past few weeks, Comet 103P/Hartley 2 been fairly dim at magnitude 5 or 6, best viewed from very dark and moonless skies for experienced observers.  In the coming days, the comet is expected to be barely visible to the unaided eye but best spotted in binoculars and telescopes.  Unfortunately, the next full moon will be on October 22 and will make the viewing of Hartley 2 tougher for the rest of the month.

During the week of October 18, the best time to look for Comet 103P/Hartley 2 will be at dawn when it is high above the northeast horizon.  The fuzzy visitor will pass by the brilliant star Capella in the constellation Aurgia.  On October 20, the comet will be 6 degrees to the lower right of Capella.  At this time, it will be 0.12 astronomical units from Earth and at a magnitude of 4, which is about the brightness of the stars in the handle of Ursa Minor, the Little Dipper.  Look for a faint fuzzy patch of the comet’s nucleus. Viewing will be best through binoculars.  The comet’s kryptonite green halo is diffuse and can be difficult locate.  Towards the end of the month, the comet will be lower in the constellation of Gemini.

 By November, Comet 103P/Hartley 2 will be fading in view as it moves near Sirius, away from both the Sun and Earth.  On November 4, a NASA EPOXI spacecraft, a continuation of the Deep Impact mission, will fly by the comet's small nucleus which is estimated to be only a mile in diameter.  The probe will take pictures and other data at some 600 miles. 

  Enjoy this comet because at this moment in time it's the brightest visitor which we will see in 2010. 

  *  The above is courtesy of Jim Todd, OMSI Planetarium Manager

Regional Weather Experts Will Once Again Descend On Portland To Predict This Coming Winter’s Weather!

Portland, Oregon (September 23^rd 2010) - La Nina is back! The Portland International Airport recorded its wettest June in history this year, along with its coldest summer in 17 years. Records fell all across the Pacific Northwest this spring and summer. Is our record setting weather expected to continue into the winter months? What about our chances for low elevation snow? The Oregon chapter of the American Meteorological Society is proud to announce the 18^th annual “What Will the Winter Be Like” forecast meeting. This year’s event will once again be held at the Oregon Museum of Science and Industry (OMSI), located at 1945 S.E. Water Avenue in Portland on Saturday, October 16^th 2010 from 10 am to 12 noon. The meeting will be free, open to the general public and will also include our annual “snowflake contest” where attendees can take a guess at when the first snow will fall in Portland this coming winter. Prizes will be awarded to the winner(s) after the first snowfall. Last year’s meeting drew a record crowd of nearly 300 people from all across Oregon and Washington. In keeping with tradition, regional news media is again encouraged to advance and cover this informative event. 

*The above is always an interesting presentation.  Speakers include my good friend, KPTV Chief Meteorologist Mark Nelsen and representatives from the National Weather Service.  Lots of guess work about what to expect this winter!  If you are a weather "junky", I recommend attending.  

I did a story with an arborist this week.  The point of the story was doing a visual inspection of your trees before this winter.  As you know, an active winter is likely, which means a heightened chance of high winds in the valley.  I have five fir trees in my yard and two big maples and always think about the possible threat to my property.  Here is what I learned:

1.  Look at the base of your Douglas Fir trees.  Woody mushroom growths are a sign of possible rot developing        in the trunk.  The mushrooms can also grow at height alone the trunk.  Fungus, spawned by rot causes the      growth.   Call an arborist, they will drill into the tree to discover the extent of disease.  The rot can develop         over a period of decades, meaning you may or may not have reason for concern. 

2.  Thinning the branches on your trees, allowing wind to sail through is always a good idea, but should be            done by a professional.  

3.   Split trunks are often a sign of weakness and should be eliminated when the tree is young.

4.   A "V" growth of a major branch is often accompanied by a trailing crack in the wood along on the trunk.           Do a visual inspection.  If you spot a crack, trim growth off of the large branch growing from the V to                 eliminate weight.  A cable for support may be used.  You should not simply cut the large branch off, doing         so will induce rot into the main tree trunk.

5.  Ivy growing around a tree trunk is bad and can introduce bad health to the tree.  Cut the ivory at the              ground and get rid of it. 

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The good news is that healthy large trees, including firs will rarely fail, even with winds of 100 mph.  Branches may fall, but a healthy tree will likely survive.  The main concern for healthy trees, no matter how large, is a heavy rain event, saturating the soil prior to a wind storm.  All trees have a risk of being up-rooted in such an event.  But again, the likely hood of a mature trunk snapping in the wind is low.  It is true, that an isolated tree is at greater risk than those in the middle of a grove.  However, if a tree has been isolated on a hilltop it's entire life, the tree has likely deep-rooted itself and will survive a harsh environment.  Remember, our big wind storms produce a south to north blowing wind up the gut of the Willamette valley.  

Here is the list of weekend Rain Totals:

Cougar, Wa.  7.96" / Vancouver 1.48" / Castle Rock 1.45" /Astoria 3.42" / Seaside 3.06"/ 

Bonneville 2.50" / Gresham 2.10" / Estacada 1.91"/ Troutdale 1.57"/ Portland PDX 1.34"/

Downtown Portland 1.68"/ Tillamook 1.27"/ Salem 1.25"/ McMinnville 1.07"/ Grande Ronde .80"/Hillsboro .70"/

Vernonia .52"/ Hood River .33"

Headlines from the National Weather Association conference I attended in Tucson, include more numerous La Nina years expected and new radar technology installation beginning January 2011.  

A climate, long range forecast expert believes this winter's La Nina will kick-off a 20 year cycle of more numerous La Nina's.  The presenter also believes the upcoming cycle of weather will have similarities to the years 1950 - 1970.  So I did some checking:  The average water year total from 1950 - 1970 is 37.69 inches.  Compared to our last 10 year average of 33.23 inches.  If the theory holds, the up-coming water year seasons will average an extra month of rain or 4.46" more than we have seen lately.  Snow data also favors more active weather to come.  Moderate to strong La Nina's between 1950 - 1970 averaged 11.9" of snow.  Our last 10 year average is 4.4", even with the 23.7" of the 2008-2009 winter season.  Put it all together and you have more clues hinting at active winters coming our way!  

The second headline is the first national radar upgrade since the 1988 doppler technology.  Installation will take place between January 2011 and March 2013.  The new technology is called "Dual - Polarization".  The radar will slice storms on both a vertical and horizontal axis at the same time.  The technology will provide better data of how much rain is falling, more accuracy in showing hail verses rain and have the ability to show debris uplifted by tornadoes!  By showing debris in the air, tornado confirmation will be much higher.  

With one day left in the month, it is worth noting the many records that have been tied or broken this month.  I cannot recall a month in recent memory that recorded 9 records!  Here is the list for what has been anything but a normal September:

Sept. 7th:  1.55" of rain / new daily record for the date

Sept. 7th:  1.03" of rain in one hour / new all-time Portland rain record for one hour

Sept. 9th:  High temperature 65 degrees / ties low-high temperature record for the date

Sept.  16:  Low of 61 degrees / record high-low temperature for the date

Sept.  17:  Low of 62 degrees / record high-low temperature for the date

Sept.  18:  .97" of rain / new daily record for the date

Sept.  26:  Low of 61 degrees / record high-low temperature for the date

Sept. 27:  Low of 63 degrees / record high-low temperature for the date

Sept. 28:  Low of 62 degrees / record high-low temperature for the date

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It appears September will end with 3.36" of total rainfall.  The total is 1.71" above the normal of 1.65".  Our wet September does not make the top five.  The wettest September at PDX (records back to 1941) is 4.30", 1986.  The wettest all locations dating to 1871 is 5.52", 1927.

What a month is was!!