First Freeze?

   Well it has been a few days since the last post so I thought I might put one up for all us weather nuts.  So After this mornings rain, PDX is at about .43" for the month.  Before the rain this morning we were about 1.3" below average for the month alone.  For the year we are about 5.3" short.  So lets hope for some more… plus it's nice to hear when I am trying to go to bed at 10 AM after the morning show.  As for the first freeze, on average it is around November 8th.  The earliest first freeze record that I could find was on October 5th, 1993, with a really old record on October 13th, 1881! (who knows how accurate that is…1881) 
    I don't think we will see any freezing temps here in Portland in the next few weeks but it is going to be cold for a few nights7day_640x480
.  The average minimum temperature for this time of year is 51F.  We will see some mornings colder then that with tomorrow morning being around 44F.  If you goto the Cascades and some Central OR areas they will be at or below freezing tomorrow morning.  The NWS put out a special weather statement this morning about that. 
   For the rest of the week, I see some more rain Wednesday evening into Thursday.  After that we will be warming up to above average temps for the weekend.  Have a good night everyone!

Rob Martin

*UPDATE*

Ok so in response to Eternal Yamcha’s question posted at 1:08AM: One easy,
one REALLY geeky/long.

 

For the easy answer, the overall pattern does not support
east to west movement for this specific Low. 
This means that it gets blocked so to speak.  In terms of precip, in washington,
from say Bellingham
to the Cascades on the East, the precip amounts will range from .2” to maybe 1”
towards the Mountains from this cycle. 
Storms like this can die off when it hits land just because the
“ingredients” to keep it going are not available on land anymore, where over
the oceans, it has an abundance of “ingredients” 
  

 

Really Geeky/Long (w/ help from my class notes in college)-

 There are many
different ways you can explain this depending on what methods you start
from.  I am going to use Rossby Wave
Thinking.  If you are not familiar with
it you can Google or Wiki it and get an idea who/what  Rossby was/is. 
To start easy, let’s think of a wave. 

 

The top of the wave is a HIGH and the bottom is a LOW.  A wave is Progressive a lot of the time (not
always), but the over all flow of the “weather” is generally, usually, most of
the time, progressive.  Progressive means
moving “forward” or in our case (N Hemisphere) from west to east.   Another term I am going to use is Zonal
Flow.  Zonal flow is the flow of the
“weather” moving DIRECTLY west to east(Progressive Flow) where the opposite is
Retrogressive, or moving “backwards”. 

 

Back to Rossby… I am going to take a Synoptic Scale approach
to the Rossby thinking.  The significance
is that as the mean Zonal Flow increases, the wave number of the stationary
wave decreases, there are fewer stationary or retrogressive waves, and the
overall pattern become Progressive.  

Experience:  In Strong Zonal Flow, embedded waves move
rapidly from west to east. With Weak Zonal Flow, we often have blocking
situations, as in its stalls.  So in this
case there is Weak Zonal Flow.  If you
look at the same time frame for the GFS at two levels (say 300mb and 850mb) you
will notice that as the “low” stalls, the upper levels have Weak Zonal Flow (
Over Vancouver Island at that particular time, the flow is strong SW, not
W).  This would lead to blocking/stalling
in Rossby Thinking. 

-RM

52 Responses to First Freeze?

  1. Hi Guys,
    Wrath is onto something, if the first low doesn’t hit, it will flatten the ridge (retrograde) and leave the door wide open for the next low. Both will pack a very heavy moisture punch, so we could very well be looking at our first big storm of the season.
    Long range forecast models agree with that theory as well, some of the models actually have BOTH storms hitting the Pacific Northwest.
    As the hurricane season should be coming to an end shortly, we are wrapping up a very busy hurricane season, and as Mark has pointed out in the past, and I brought up a few weeks ago, active hurricane seasons generally lead to a pretty active winter here in the northwest. At minimum, statistically speaking, we should have at least one real good storm. Last active hurricane season on record was 2003 (one of the most active of all time), which was followed by a winter we saw record breaking cold, and a couple fairly decent (for this day and age anyway) snow/ice storms.
    Also, did you know there are only 90 more days left in the xmas chopping season?

  2. Hi Guys,
    Wrath is onto something, if the first low doesn’t hit, it will flatten the ridge (retrograde) and leave the door wide open for the next low. Both will pack a very heavy moisture punch, so we could very well be looking at our first big storm of the season.
    Long range forecast models agree with that theory as well, some of the models actually have BOTH storms hitting the Pacific Northwest.
    As the hurricane season should be coming to an end shortly, we are wrapping up a very busy hurricane season, and as Mark has pointed out in the past, and I brought up a few weeks ago, active hurricane seasons generally lead to a pretty active winter here in the northwest. At minimum, statistically speaking, we should have at least one real good storm. Last active hurricane season on record was 2003 (one of the most active of all time), which was followed by a winter we saw record breaking cold, and a couple fairly decent (for this day and age anyway) snow/ice storms.
    Also, did you know there are only 90 more days left in the xmas chopping season?

  3. Hi Guys,
    Wrath is onto something, if the first low doesn’t hit, it will flatten the ridge (retrograde) and leave the door wide open for the next low. Both will pack a very heavy moisture punch, so we could very well be looking at our first big storm of the season.
    Long range forecast models agree with that theory as well, some of the models actually have BOTH storms hitting the Pacific Northwest.
    As the hurricane season should be coming to an end shortly, we are wrapping up a very busy hurricane season, and as Mark has pointed out in the past, and I brought up a few weeks ago, active hurricane seasons generally lead to a pretty active winter here in the northwest. At minimum, statistically speaking, we should have at least one real good storm. Last active hurricane season on record was 2003 (one of the most active of all time), which was followed by a winter we saw record breaking cold, and a couple fairly decent (for this day and age anyway) snow/ice storms.
    Also, did you know there are only 90 more days left in the xmas chopping season?

  4. jacob BPA says:

    Rob Who
    Was going to post the Winter Weather Forecast But havent been able to go to work till today so may do it Wed night
    Family and I were in a car Wreck Sunday
    Everyone is ok just banged up, But was quite a ride
    Hrdro into the Far left Concrete Barrier on the 205 Bridge then across 4 lanes of Trffic into the other Barrier and Didnt hit anyone
    Now try that one
    As For the Weather things look interesting I ll Give You a Hint for the Winter Months to Come
    1-2 Wind Storms Meaning 60Mph
    Rain Should Be About Avg
    Ill Share more later
    Fab 5 Get Ready for our nightly meeetings we need to winterize the RV and Plane

  5. HIO Phil (Punxsutawney) says:

    Hillsboro airport missed the record low for the 23rd by one degree. 35 vs 34 degrees. Portland (record 40)and Salem (record 32) missed by a fair amount at 44 for a low each.

  6. HIO Phil (Punxsutawney) says:

    Hillsboro airport missed the record low for the 23rd by one degree. 35 vs 34 degrees. Portland (record 40)and Salem (record 32) missed by a fair amount at 44 for a low each.

  7. HIO Phil (Punxsutawney) says:

    Hillsboro airport missed the record low for the 23rd by one degree. 35 vs 34 degrees. Portland (record 40)and Salem (record 32) missed by a fair amount at 44 for a low each.

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