Jump to content

Welcome to our forums!

Sign In or Register to gain full access to our forums. By registering with us, you'll be able to discuss, share and private message with other members of our community.

Welcome!

Thanks for stopping by the Weather Forums! Please take the time to register and join our community. Feel free to post or start new topics on anything related to the weather or the climate.


Photo

Best synoptic conditions for frost in September/October?

- - - - -

  • Please log in to reply

#1
WeatherArchive

Posted 29 September 2017 - 01:42 AM

WeatherArchive

    Forum Member

  • Members
  • PipPipPip
  • 348 posts
  • LocationStayton

What our good setup scenarios for it and what are some notable ones especially west of the Cascades?  Any top picks?



#2
Phil

Posted 29 September 2017 - 03:18 PM

Phil

    Forum Fantastic

  • Members
  • PipPipPipPipPipPipPipPip
  • 20128 posts
  • LocationCabin John, MD.
When molecular kinetic energy is low.
Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Warm Season 2018
90+ degree days: 5
Thunderstorm Days: 5
Severe Days: 1
Total rainfall: 1.77”
Highest Gust: 54mph
Warmest High: 94.6*F
Warmest low: 65.5*F

Live Weather Stream

#3
BLI snowman

Posted 29 September 2017 - 07:07 PM

BLI snowman

    Special Contributor

  • Members
  • PipPipPipPipPipPipPip
  • 6989 posts
  • LocationBlythe, CA

http://mp1.met.psu.e...2000/us0923.php

 

http://mp1.met.psu.e...1985/us1009.php

 

http://mp1.met.psu.e...2003/us1031.php


  • Phil likes this

#4
wx_statman

Posted 29 September 2017 - 10:06 PM

wx_statman

    Advanced Member

  • Members
  • PipPipPipPipPipPip
  • 4504 posts
  • LocationPortland, OR

What our good setup scenarios for it and what are some notable ones especially west of the Cascades?  Any top picks?

 

You want the same setup that would deliver an Arctic blast during the winter. GOA ridge with a trough over us and cold northerly flow. Clear skies and calm winds as well. Mid-Septembers of 1965 and 1970 are excellent examples of early freezes along the I-5 corridor, although it has happened as early as August 18, 1973 (33 in Olympia and 31 in Toledo, WA). 


  • Phil and WeatherArchive like this

#5
DareDuck

Posted 29 September 2017 - 11:03 PM

DareDuck

    Forum Contributor

  • Members
  • PipPipPipPip
  • 749 posts
  • LocationBend, OR
Interesting to note how the lows over the east side really start to separate from the west side of Cascades this time of the year. Up until a couple weeks ago the lows weren't all that far apart. Now its the time of the year where freezes will be more common out here.

Bend, OR

Elevation: 3550'

 

Snow History:

Nov: 1"

Dec: .5"

Jan: 1.9"

Feb: 12.7"

Mar: 1.0"

Total: 17.1"

 

2016/2017: 70"

2015/2016: 34"

Average: ~25"

 

2017/2018 Winter Temps

Lowest Min: 1F on 2/23

Lowest Max: 23F on 12/24, 2/22

Lows <32: 87

Highs <32: 13

 


#6
snow_wizard

Posted 30 September 2017 - 09:54 AM

snow_wizard

    The Snow Wizard

  • Mods
  • 13673 posts
  • LocationCovington, WA

Clippers are another thing that works really well.  They bring cold air, but very little moisture so we end up with low dp to go along with the cold air mass left in the clipper's wake.  October 2006 was probably the most over performing October cold snaps on record for my area and it was not a classic Arctic blast setup.  All time October record lows were set at some stations.  September 1949 was another example...widespread frost on Sept 12 with a very unimpressive upper level setup.  That one had everything to do with surface pressure gradients.


Death To Warm Anomalies!

 

Winter 2017-18 stats

 

Total Snowfall = 7.7"

Coldest Low = 19

Lows 32 or below = 51

Highs 32 or below = 0

Lows Below 20 = 0

Highs 40 or below = 21

 

 


#7
wx_statman

Posted 30 September 2017 - 10:30 AM

wx_statman

    Advanced Member

  • Members
  • PipPipPipPipPipPip
  • 4504 posts
  • LocationPortland, OR

Clippers are another thing that works really well.  They bring cold air, but very little moisture so we end up with low dp to go along with the cold air mass left in the clipper's wake.  October 2006 was probably the most over performing October cold snaps on record for my area and it was not a classic Arctic blast setup.  All time October record lows were set at some stations.  September 1949 was another example...widespread frost on Sept 12 with a very unimpressive upper level setup.  That one had everything to do with surface pressure gradients.

 

It was still a classic cold pattern. Upper level low dropping south from BC with cold, dry northerly flow. Granted, the offshore ridge wasn't very impressive but it was still there.

 

Halloween 2006 was more of a classic clipper. That cold snap really overachieved considering the lackluster pattern. 



#8
WeatherArchive

Posted 01 October 2017 - 01:56 AM

WeatherArchive

    Forum Member

  • Members
  • PipPipPip
  • 348 posts
  • LocationStayton

Here is September 1965 for Salem (my area). It pegged a low of 30F. Is that data correct?  https://www.wundergr...ic=&reqdb.wmo= 

 

Look at May and June. May had 33F and June had 36F for the monthly lows! Brrrrrrrrrrr!   https://www.wundergr...gic=&reqdb.wmo=

 

https://www.wundergr...gic=&reqdb.wmo=

 

Was most of that summer northerly flow?

 

Here is more imagery.  https://www.wundergr...gic=&reqdb.wmo=

 

http://www.meteociel...&region=&mode=0



#9
WeatherArchive

Posted 01 October 2017 - 02:03 AM

WeatherArchive

    Forum Member

  • Members
  • PipPipPip
  • 348 posts
  • LocationStayton

Here is more imagery.  Here is September 17th 1965 which pegged 28F. It says 30F but when you click on it the records tab says 28F.  https://www.wundergr...ilyHistory.html

 

Here is the Metociel imagery for that date. http://www.meteociel...region=&mode=0 I set it to Temperature et flux 850Pa. Hem.Nord for that one imagery.  It's there also in the Toutes Les Cartes which means all imagery.   Europe first then North America last.



#10
WeatherArchive

Posted 01 October 2017 - 02:05 AM

WeatherArchive

    Forum Member

  • Members
  • PipPipPip
  • 348 posts
  • LocationStayton

Clippers are another thing that works really well.  They bring cold air, but very little moisture so we end up with low dp to go along with the cold air mass left in the clipper's wake.  October 2006 was probably the most over performing October cold snaps on record for my area and it was not a classic Arctic blast setup.  All time October record lows were set at some stations.  September 1949 was another example...widespread frost on Sept 12 with a very unimpressive upper level setup.  That one had everything to do with surface pressure gradients.

Was  September 1965 a clipper then?  That whole year seems a lot of chilly lows.