SFC v. 925 mb v. 850 mb: temp.'s for 21 of coldest airmasses in SE since 1950

[GaWx]

 **Updated on 1/7/14 for 1/6-7/14 airmass**

***Reupdated on 1/11/14 for 1/6-7/14 airmass based on reanalysis, which has -18 C at 925 mb and -17 C at 850 mb as opposed to initial indications that they were both -19 C***

 

 Going back to 1950, I looked today at 21 of the coldest airmasses to affect many in the SE US and compiled the coldest at the surface, 925 mb, and 850 mb at KATL as requested.

 

sfc/925 mb/850 mb KATL (all in degrees C)
 

1/6-7/14: -14/-18/-17
1/23-4/03: -13/-16/-18
2/4-5/96: -14/-16/-16
1/18-9/94: -14/-13/-8
12/23-4/89: -14/-19/-16
1/27-8/86: -13/-18/-22
1/20-1/85: -22/-23/-19
12/24-5/83: -18/-24/-19
1/16-7/82: -18/-10/-5
1/10-1/82: -21/-19/-15
1/9-11/78: -13/-17/-11
1/29/77: -13/-14/-8
1/19/77: -17/-20/-17
1/17/77: -17/-18/-12
1/8-9/70: -17/-16/-19
1/30/66: -19/-25/-17
1/24/63: -19/-16/-8
12/12-13/62: -17/-20/-20
2/17/58: -15/-18/-15
2/2/51: -13/-16/-11
11/25/50: -16/-20/-18

 

 

I complied the following stats based on this list:

 

1. Coldest level for each of the 21 airmasses: sfc 4; 925 mb: 13; 850 mb: 4

 

2. Warmest level for each of the 21 airmasses: sfc 9; 925 mb: 1; 850 mb: 11

 

3. Record coldest for these 21 airmasses: sfc -22; 925 mb: -24; 850 mb: -22

 

4. Avg. of the coldest for these 21 airmasses: sfc -16; 925 mb: -18; 850 mb: -15. So, on average, the sfc was 2 warmer than 925 mb and 1 colder than 850 mb but the range has been very wide (see next line)

 

5. Range of temp. differences between levels (all wide): sfc vs. 925  +6 to -8; 925 vs. 850: +4 to -8; sfc vs. 850: +9 to -13. So, the 21 different cold airmasses varied widely regarding sfc vs. 925 vs. 850.

----------------------------------------------------------------------------------------------------------------------

 

925 mb and 850 mb temperature data at six hour intervals from here (0C = 273K):

http://www.esrl.noaa.gov/psd/data/composites/hour/

KATL surface temperature data from NOAA

 

 

 

[dsaur]

Larry, what do you have on the 63 outbreak?  As I recall, it was 6 at 3:30pm, or so, if that is the one I'm thinking of.  Mine would have been 63/64, or 64/65, and I'm pretty sure there weren't many this cold in the afternoon.  It could have been the 62 one, but I think I was older.  Thanks,  Tony

[Lookout]

Peachtree_City GA US KFFC 1 33.37 -84.57 244 72215


Date:1200Z  7 JAN 14
Station: KFFC
WMO ident:  72215
Latitude:   33.37
Longitude: -84.57
Elevation: 244.00
-------------------------------------------------------------------------------
LEV PRES  HGHT  TEMP  DEWP  RH  DD   WETB DIR SPD THETA THE-V THE-W THE-E   W
     mb     m     C     C    %   C     C  deg knt   K     K     K     K    g/kg
-------------------------------------------------------------------------------
SFC 1002   244 -13.3 -19.3  61  6.0 -14.4 330   7 259.7 259.8 258.6 262.0  0.83
  1 1000   257 -13.3 -20.3  56  7.0 -14.5 320  12 259.9 260.0 258.6 261.9  0.76
  2  990   333 -14.1 -21.1  55  7.0 -15.3 320  13 259.8 259.9 258.5 261.8  0.72
  3  926   835 -18.9 -22.9  71  4.0 -19.5 334  20 259.9 260.0 258.5 261.7  0.65
  4  925   843 -18.9 -22.9  71  4.0 -19.5 335  20 260.0 260.1 258.5 261.8  0.65
  5  914   932 -19.1 -24.1  65  5.0 -19.8 333  23 260.7 260.8 258.9 262.3  0.60
  6  897  1073 -16.5 -27.5  38 11.0 -18.0 322  30 264.8 264.8 261.7 266.0  0.45
  7  886  1166 -12.7 -24.7  36 12.0 -14.7 314  35 269.6 269.7 265.6 271.3  0.58
  8  881  1209 -11.7 -26.7  28 15.0 -14.2 310  37 271.1 271.2 266.4 272.5  0.49
  9  874  1271  -9.7 -44.7   4 35.0 -13.5 310  37 273.8 273.8 267.4 274.1  0.08
 10  869  1315  -8.3 -55.3   1 47.0 -12.6 310  37 275.7 275.7 268.5 275.8  0.02
 11  850  1487  -7.1 -40.1   5 33.0 -11.6 310  36 278.7 278.7 270.6 279.2  0.14
 12  835  1626  -5.7 -33.7   9 28.0 -10.4 304  36 281.6 281.7 272.6 282.5  0.27
 13  735  2622  -7.5 -55.5   1 48.0 -12.7 304  44 290.1 290.1 276.7 290.2  0.03
 14  723  2751  -5.5 -53.5   1 48.0 -11.3 310  49 293.7 293.7 278.5 293.8  0.04
 15  714  2850  -2.7                      308  54 297.8                        
 16  701  2996  -1.3 -40.3   3 39.0  -8.5 305  60 300.9 301.0 282.0 301.5  0.16
 17  700  3007  -1.3 -40.3   3 39.0  -8.5 305  61 301.0 301.1 282.0 301.6  0.16
 18  650  3596  -1.9 -38.9   4 37.0  -9.2 301  62 306.8 306.9 284.4 307.5  0.20

Peachtree_City GA US KFFC 1 33.37 -84.57 244 72215


Date:0000Z  7 JAN 14
Station: KFFC
WMO ident:  72215
Latitude:   33.37
Longitude: -84.57
Elevation: 244.00
-------------------------------------------------------------------------------
LEV PRES  HGHT  TEMP  DEWP  RH  DD   WETB DIR SPD THETA THE-V THE-W THE-E   W
     mb     m     C     C    %   C     C  deg knt   K     K     K     K    g/kg
-------------------------------------------------------------------------------
  0 1000   224                                                                 
SFC  997   244  -7.1 -17.1  45 10.0  -9.4         266.3 266.4 264.0 269.1  1.00
  2  979   386  -8.7 -19.7  41 11.0 -10.9         266.1 266.2 263.4 268.4  0.82
  3  925   825 -12.9 -20.9  51  8.0 -14.4 300  22 266.1 266.2 263.4 268.3  0.78
  4  868  1306 -17.5 -21.4  72  3.9 -18.1 304  27 266.2 266.3 263.6 268.5  0.80
  5  858  1392 -18.3 -21.8  74  3.5 -18.8 304  27 266.3 266.4 263.6 268.5  0.78
  6  850  1462 -18.7 -22.8  70  4.1 -19.3 305  28 266.6 266.7 263.6 268.6  0.72
  7  844  1515 -18.9 -23.9  65  5.0 -19.7 304  29 266.9 267.0 263.7 268.8  0.66
  8  837  1577 -18.5 -26.5  49  8.0 -19.6 304  30 267.9 268.0 264.3 269.5  0.52
  9  831  1631 -16.7 -30.7  29 14.0 -18.6 303  32 270.4 270.5 265.7 271.5  0.36
 10  821  1722 -15.7 -32.7  22 17.0 -17.9 302  34 272.4 272.4 266.9 273.3  0.30
 11  786  2051 -14.5 -33.5  18 19.0 -17.1 299  40 277.1 277.1 269.9 278.0  0.29
 12  780  2109 -13.7 -42.7   7 29.0 -16.9 298  42 278.6 278.6 270.5 278.9  0.11
 13  772  2187 -13.3 -40.3   8 27.0 -16.5 298  43 279.8 279.8 271.3 280.3  0.15
 14  700  2928 -16.3 -61.3   1 45.0 -19.4 290  59 284.4 284.4 273.7 284.5  0.01
 15  676  3190 -17.1 -59.1   1 42.0 -20.1 286  66 286.4 286.4 274.8 286.5  0.02
 16  665  3313 -16.7 -55.7   2 39.0 -19.8 285  69 288.2 288.2 275.7 288.3  0.03
 17  655  3427 -14.9 -59.9   1 45.0 -18.5 283  72 291.5 291.5 277.4 291.5  0.02
 18  645  3543 -15.3 -60.3   1 45.0 -18.8 281  75 292.3 292.3 277.8 292.4  0.02
 19  635  3661 -12.7 -58.7   1 46.0 -16.9 280  78 296.6 296.6 279.8 296.7  0.02
 20  626  3770 -11.5 -57.5   1 46.0 -16.1 278  81 299.2 299.2 281.0 299.3  0.03
 21  610  3968 -11.7 -57.7   1 46.0 -16.3 276  86 301.2 301.2 281.8 301.2  0.03
 22  599  4108 -10.3 -49.3   2 39.0 -15.3 274  89 304.3 304.4 283.2 304.6  0.07

Larry, here are the observed soundings for ffc for last night and this morning. I wish we had observations at atl and gvl to get a better idea of the airmass to the north. For that matter, i wish there were more balloon observations in every state. I know it's expensive but having the huge distances between actual upper air observations never has made sense to me.

[GaWx]

Larry, what do you have on the 63 outbreak?  As I recall, it was 6 at 3:30pm, or so, if that is the one I'm thinking of.  Mine would have been 63/64, or 64/65, and I'm pretty sure there weren't many this cold in the afternoon.  It could have been the 62 one, but I think I was older.  Thanks,  Tony

 

Tony,

  Regarding only 6 at 3:30 PM, I can't find anything even close to that cold around that time. However, at 4 PM at KATL, 1/10/82 was 10 and 1/20/85 was at 8. These are the coldest by a good margin in recent decades.

[dsaur]

Tony,

  Regarding only 6 at 3:30 PM, I can't find anything even close to that cold around that time. However, at 4 PM at KATL, 1/10/82 was 10 and 1/20/85 was at 8. These are the coldest by a good margin in recent decades.

Thanks, man.  You've just reported on the shot memory of another old man   The Ex Stat is reporting a 6.6 this morning, and my lowest was 7.3, or .9, don't remember...see....there it is again, lol. T

[Lookout]

Tony,

  Regarding only 6 at 3:30 PM, I can't find anything even close to that cold around that time. However, at 4 PM at KATL, 1/10/82 was 10 and 1/20/85 was at 8. These are the coldest by a good margin in recent decades.

What was amazing about that outbreak was it was in the -20s below zero in eastern Tn in 85. I was shocked when I saw those numbers. I had no idea it ever got that cold in eastern tn. So no wonder it was so cold with that outbreak with temps like that upstream. I mean that was about 25 to 30 degrees colder than this outbreak in tn!

[dsaur]

What was amazing about that outbreak was it was in the -20s below zero in eastern Tn in 85. I was shocked when I saw those numbers. I had no idea it ever got that cold in eastern tn. So no wonder it was so cold with that outbreak with temps like that upstream. I mean that was about 25 to 30 degrees colder than this outbreak in tn!

Lol, I know.  This gets hyped up until folks are afraid of the weather because it's the end of the world, and it was far colder then, and the world didn't end.  Instead of hyping fear, I wish they educate.  Tell folks how to prepare, step by step.  What to do if this happens, how to cope, who to call for help, how to get layers on properly, etc.  In stead it's flee, flee the world is ending, not this is nothing new folks, be calm, and here's how to deal

  Larry, what about the morning temps back then? The 60's.  Thanks, T

[GaWx]

 

Larry, here are the observed soundings for ffc for last night and this morning. I wish we had observations at atl and gvl to get a better idea of the airmass to the north. For that matter, i wish there were more balloon observations in every state. I know it's expensive but having the huge distances between actual upper air observations never has made sense to me.

 

 

Chris,

 Thanks for posting those soundings here. Based on those as well as other things I've seen, I'm going with -19 C for the coldest at both 925 mb and 850 mb at KATL. The 850 mb level was coldest at 0Z on 1/7 whereas the 925 mb level was coldest at 12Z on 1/7. Interestingly, the 850 mb temp. warmed a whopping nearly 12 C during those 12 hours! The surface's coldest was -14 C (+6 F), which was set both at 12Z and 13Z on 1/7. The last time KATL got down as low as +6 F was 2/5/96. The last time the 925 mb temp. was as cold as -19 C was the -19 C during the 12/23-4/89 period. The last time the 850 mb temp. was as cold as -19 C was the -22 C during the 1/27-8/86 period.

 

 I updated the table to include 1/7/14 (now 21 airmasses).

[GaWx]

Lol, I know.  This gets hyped up until folks are afraid of the weather because it's the end of the world, and it was far colder then, and the world didn't end.  Instead of hyping fear, I wish they educate.  Tell folks how to prepare, step by step.  What to do if this happens, how to cope, who to call for help, how to get layers on properly, etc.  In stead it's flee, flee the world is ending, not this is nothing new folks, be calm, and here's how to deal

  Larry, what about the morning temps back then? The 60's.  Thanks, T

 

Tony,

  The coldest low was -3, reached both in Jan. 1963 and Jan. 1966!

[JQPublic]

Wow! Just goes to show how rare these cold outbreaks have been as of late.  If only I could have been alive in the 70's and old enough in the 80s to remember

[dsaur]

Thanks, Larry, whew.....  I'm glad I'm not losing my mind, it must have been walking to school, and not home.  Which makes sense as I would have seen the thermometer as I was leaving the house.  We had a pretty good one for those days, and it mounted out on a back porch window, so I saw it everytime I left the house, or came in.  I was always aware of the temp my whole childhood.  I just thought everyone was that way, but apparently not .  The sixty's had some cold days, lol.  But it was so dry for most of them.  Brick would have loved the 60's for cold and dry. 

 

  John Q, I hope for you a very cold future!!  The cold spells are the things I remember after the sleet/snow.  I hope there are a bunch more in your future   T

[GaWx]

Chris,

 Thanks for posting those soundings here. Based on those as well as other things I've seen, I'm going with -19 C for the coldest at both 925 mb and 850 mb at KATL. The 850 mb level was coldest at 0Z on 1/7 whereas the 925 mb level was coldest at 12Z on 1/7. Interestingly, the 850 mb temp. warmed a whopping nearly 12 C during those 12 hours! The surface's coldest was -14 C (+6 F), which was set both at 12Z and 13Z on 1/7. The last time KATL got down as low as +6 F was 2/5/96. The last time the 925 mb temp. was as cold as -19 C was the -19 C during the 12/23-4/89 period. The last time the 850 mb temp. was as cold as -19 C was the -22 C during the 1/27-8/86 period.

 

 I updated the table to include 1/7/14 (now 21 airmasses).

 

***Table reupdated on 1/11/14 for 1/6-7/14 airmass based on reanalysis, which has -18 C at 925 mb and -17 C at 850 mb as opposed to initial indications that they were both -19 C***

 

 The 850 mb level was coldest at 0Z on 1/7 while the 925 mb level was coldest at 6Z on 1/7 with 12Z on 1/7 only barely warmer, if that. The 925 mb level's -18 C was the coldest since 12/23-24/89's -19 C. The 850 mb level's -17 C was the coldest since 1/23-24/03's -18 C.