Author Topic: Spring 2013 Cold Air Mass Movement Projections  (Read 20868 times)

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Offline richard583

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #50 on: May 12, 2013, 09:22:27 PM »
Quote
Each winter, on average, your risk of frost is from October 17 through April 11.

Almost certainly, however, you will receive frost from November 1 through March 29.

You are almost guaranteed that you will not get frost from April 24 through October 2.

Your frost-free growing season is around 189 days.

 :shock: ](*,)

Either they're info is a bit off, or this is really unusual.

hey again "WeatherHost".

With considering both this, along with the whole advent of the stronger cold's dipping south to where you guys are there at this point, ...

.. I'd say it's colder this year certainly, than average. Cooler, with also being drier, here more out West where I am.

My own view, more global (N. hem. leastwise.) more climatological at this point, is that even with main cold stores looked at more annually to the north moving to slightly greater each year, those increased stores have been losing grip this year more easily both during the winter and also as things have started to warm through earlier spring. .. Or as day-length has begun to increase more substantially leastwise.

That is, where considering the state and shape of cold stores to the north more at this point and more leading up to it this year, main cold to the north, if being generated better, not holding on to consolidate as well as I'm expecting it to over the next few years. Even 5 to 7.

Just general conjecture.
« Last Edit: May 20, 2013, 04:02:00 AM by richard583 »
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Offline Dr Obbins

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #51 on: May 12, 2013, 09:39:23 PM »

hey "WeatherHost".

Not really sure how unusual this is, but Louisville, Nashville and Memphis all have similar statements.

Checking a few different resources more horticulturally focused I found this below.



Tullahoma, closest of all of the main cities listed here to where "SlowModem" is there in TN, near Watts Bar Dam, shows the average "last" frost date in Spring being today's date in fact.
It is unusual here in central KY - "Todays low of 40° at 5:48 AM missed the NOAA record low of 37° set in 1951 by 3 degrees for Cave Country Weather" We also have a frost warning for tonight.
In past years we have been making good use of the swimming pool by now. Some years even as early as March, but not yet at all this year.

Offline SlowModem

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #52 on: May 12, 2013, 11:11:44 PM »
Latest from the NWS for my area:
Quote
Overnight Patchy frost after 5am. Otherwise, mostly clear, with a low around 35. North wind around 5 mph.

Monday Patchy frost before 8am. Otherwise, sunny, with a high near 69. Calm wind becoming north around 5 mph in the morning.

Monday Night Mostly clear, with a low around 41. West wind around 5 mph becoming calm after midnight.

Tuesday Partly sunny, with a high near 78. Light south wind increasing to 10 to 15 mph in the morning. Winds could gust as high as 20 mph.

It won't last long, but it might nip tender plants.  It won't be good for the bees, either.
Greg Whitehead
Ten Mile, TN USA

Offline SlowModem

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #53 on: May 13, 2013, 09:30:30 AM »
only down to 40f this morning.  Maybe we'll survive after all.  :)
Greg Whitehead
Ten Mile, TN USA

Offline Dr Obbins

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #54 on: May 13, 2013, 09:37:15 AM »
"Todays low of 37° at 5:05 AM missed the NOAA record low of 35° set in 1888 by 2 degrees for Cave Country Weather" but there was frost on the roof.

Offline WeatherHost

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #55 on: May 13, 2013, 10:33:45 AM »
KPAH hit 38, record was 37 in 1989

'Missed it by THAT much!!'

Had plenty of F.  Fog that is, no Frost though that I saw.




Offline richard583

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #56 on: May 13, 2013, 05:26:51 PM »
(.. follows in line with my projection posted on May 7th.

Where and with greater cold air's being set to move and spread south for the next several days while at the same time steadily more slowly east, the greater patterning generated by this combined movement of colder set against warmer air mass, should be increasingly more meridional

 

Click on each of these two images here just above to see a representation of the beginning of this transition. A full Northern hemispheric view of the 500mb pressure height level together with one similar, showing actual temperatures, lower in the atmosphere at the 850mb height: each 12-hrly for the past three days and ending at 12z earlier today.

(source: Unysis Weather)
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Offline SlowModem

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #57 on: May 13, 2013, 06:50:28 PM »
I hope it's over with for this year.
Greg Whitehead
Ten Mile, TN USA

Offline richard583

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #58 on: May 13, 2013, 07:13:53 PM »

.. Probably a matter of basic cold stores available at this point.

With this wave having been the last of anything more substantial still having been in place over the greater Canadian Shield or more NW over Alaska, I'd say.
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Offline WeatherHost

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #59 on: May 13, 2013, 07:58:03 PM »
I hope it's over with for this year.

Local talking head says -  probably.


Offline ocala

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #60 on: May 13, 2013, 08:26:52 PM »
Upper 40's expected tonight IMBY. That's crazy for mid May but just about a week ago we hit 48.
This should be it as the rainy season and hurricane season start June 1st.
The blues had a baby and they named it Rock & Roll

Offline richard583

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #61 on: May 17, 2013, 03:52:15 AM »

With continuing to slow its main movement east through the 22nd or so of May, greater cold air mass should move through a short period of more stepped up pace east from the 23rd through the 25th or so before slowing again.

This, while continuing to spread more southward through May 25th, before beginning to regress more back toward the north for several days.
« Last Edit: May 18, 2013, 03:27:58 AM by richard583 »
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Offline WeatherHost

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #62 on: May 17, 2013, 08:24:24 AM »
Huh?

Offline DaculaWeather

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #63 on: May 17, 2013, 09:32:42 AM »
LOL!!!! Medieval talk from good King Richard.

Offline richard583

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #64 on: May 17, 2013, 05:52:15 PM »
Huh?

hello "WeatherHost".

.. May I ask just what's confused you regarding what I've posted most recently above. ?
« Last Edit: May 17, 2013, 05:57:38 PM by richard583 »
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Offline richard583

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #65 on: May 17, 2013, 05:56:27 PM »

.. I've done what's been asked of me regarding my posting "DW".

Now your just hounding me.

This being the case in my view, I'm still willing to clarify anything in or of what I've said above - for you, that you perhaps haven't been able to understand to appreciate.

(.. This clear enough. ?)
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Offline richard583

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #66 on: May 18, 2013, 12:02:45 PM »



.. Greater cold air mass will slow its pace east on the 10th, ...

As shown within the "gif loop" accessible here following just below, after previously having been moving as a whole more swiftly eastward from the 2nd of May through the 10th, starting on the 10th greater cold air mass* did in fact begin to slow its over-all pace eastward. (Click on the image here just below, as with on those also following each main section of text further below. Allow time for loops to load in fully.)



The 700mb pressure-height level occurrs generally at near to 10,000 ft of elevation.


… and spread more south again beginning on the 13th of May.

Shown more main focus within the loop next following accessible, as a result of this general slow-down in and of greater cold air's more eastward movement, .. between the 10th and the 13th of May, where provided different more specific pathways south (both more basic topography, along with established pressure related.), some amount of more primary cold was steered more southwardi.e. previous to the 13th and if with more primary cold looked at more over-all having still been retracting more northward by degrees daily. 



And shown within this next loop following, nearer to the present, …

Since the 13th, greater cold has in fact been continuing to move and spread steadily more southward daily where looked at as a whole.


With continuing to slow its main movement east through the 22nd or so of May, greater cold air mass should move through a short period of more stepped up pace east from the 23rd through the 25th or so before slowing again.

This, while continuing to spread more southward through May 25th, before beginning to regress more back toward the north for several days.



Source for the graphic depictions used above. -  http://www.osdpd.noaa.gov/ml/mirs/Poes.html
(Check "product", for "Temperature Profile" / 700mb. Runs a day behind, generally.)

* .. All, of the bluer areas within these depictions: .. the darker, more primary, the lighter, if at one point more primary, more "secondary"; .. and where considered together "greater" cold.
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Offline richard583

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #67 on: May 20, 2013, 03:35:16 AM »

Tweet posted at 07:00z for May 20, 2013 .. @

"expansion mode": moving and spreading more southward daily.

http://www.hpc.ncep.noaa.gov/html/sfc2.shtml
Analysis/Satellite Composite
(N Amer/Pacific)
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Offline richard583

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #68 on: May 20, 2013, 05:03:17 PM »


Though certainly having lost quite a bit of its basic depth and density at this point with the general advance of spring, the gif loop accessible with clicking on the image here just below, shows cold air's general expansion southward since the 13th of this month where looked at more over-all.



This with the loop following accessible here next belowbeginning a week earlierworking to show cold's otherwise more slowed movement where looked at over-all since the 10th.




http://www.opc.ncep.noaa.gov/Loops/
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Offline richard583

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #69 on: May 21, 2013, 05:58:44 PM »


Shown within the gif loop accessible with clicking on the image just below, with some amount of main colder air still having been in place more south and having been retracting each day more northward from the 10th through the 14th, .. since the 14th, colder air still remaining through higher latitudes where looking at the main and larger N. Amer. region, has been caused to move and spread more southward daily.


(Allow time for this loop to load in fully.)

(source: Unysis Weather)
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Offline richard583

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #70 on: May 22, 2013, 03:52:41 AM »
(.. reiterating here again relative to my main projection above posted back on the 17th. @)

For the next few days, through to the 25th or so, main colder air should both continue to move and spread still more south, while at the same time being caused to pick up its movement and pace more eastward.
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Offline richard583

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #71 on: May 22, 2013, 03:58:20 PM »

Transition to much cooler temperatures in the West.




+++

Click on each of the images here above to see their main fuller-sized versions.

Image source: Earth and Large
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Offline DaculaWeather

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #72 on: May 22, 2013, 04:06:26 PM »
Torch coming next week for the middle of the country.

Offline DaculaWeather

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #73 on: May 22, 2013, 04:30:05 PM »
From a meteorologist today:
TORCH... The GWO indicating we might finally dip to negative AAM values. Haven't seen this since mid-Feb- I'm thinking a period of upper 80s, lower 90s over the central U.S. next week, later followed by mid-to-upper 80s, lower 90s from DCA to BOS late in the week. Too bad Memorial Day wasn't one week later...
If you need more information about Atmospheric Angular Momentum, here are some papers;
http://journals.ametsoc.org/action/doSearch?type=simple&filter=multiple&searchText=angular+momentum&categoryId=allJournals&history=&



Offline richard583

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Re: Spring 2013 Cold Air Mass Movement Projections
« Reply #74 on: May 23, 2013, 12:57:27 AM »
 
From a [..] meteorologist today:

TORCH... The GWO ["Global Wind Oscillation" picture at this point, is] indicating we might finally dip to negative AAM values. Haven't seen this since mid-Feb. I'm thinking [...] a period of upper 80s, lower 90s over the central U.S. next week; later followed by mid-to-upper 80s, lower 90s from DCA to BOS late in the week. Too bad Memorial Day wasn't one week later...


DC WASHINGTON/NATL  KDCA  DCA
MA BOSTON  KBOS  BOS

• 2-letter state or provide identifier
• Main station name
• 4-character international ID
• 3-character FAA ID

Whatever meteorologist, hasn't really said much about why he's thinking what he is here, has he. ?
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