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Tar Heel Snow

One More Shot: Feb 20-21 Event

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1 hour ago, NorthHillsWx said:

With surface layer above freezing high sleet totals will not verify or help with accumulation, if sleet is the precip type. Takes a lot of sleet to accumulate and usually has to be below freezing for anything other than mulch accumulations. This will skew clown maps, however, in the weenie direction. My worry level about the ML's is increasing for the Triangle area and points SE but not folding due to one run of the NAM. Sticking with my calls for now! 

Sleet will still accumulate at 33-34. I was on the wrong side of a warm nose for a storm a few years ago... the lowest my temp dropped to was 33.1, and started rising from that point and I wound up with an inch and half of sleet that also coated the roads.

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1 minute ago, burrel2 said:

Gonna come down to nowcasting for the northern upstate of SC. The HRRR and ARW both have my location's sounding going isothermal around 10am just as the heavy axis of precip moves in.  The HRRR keeps surface temps at 34-36 though which would be an issue, but I'm guessing it has it's typical bias at play here.

On the other hand, the 3km NAM has the warm nose holding strong until 1-3pm for the northern upstate. It shows surface temps at 32-33 however.

If, if.... somehow the HRRR and ARW thermal profile is right then the northern upstate could get a 4 to 6 inch past job tomorrow as the heaviest rates come through between 10:00am and 3:00pm.   If the 3km NAM is right, then we're going to see a lot of rain/white rain/sleet mix with a possible burst of moderate snow as the back edge swings through with little to no accumulations.

 

It's all comes down to that 800mb warm nose, (and possibly surface temps even if the warm nose is overcome).

Indeed it will. I’m having trouble pulling maps again today as I’m working at the sled office. I said a few days ago this could be like that March system a few years ago where it snowed all day, without accumulating. Fun times! :lol: 

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3 minutes ago, burrel2 said:

Gonna come down to nowcasting for the northern upstate of SC. The HRRR and ARW both have my location's sounding going isothermal around 10am just as the heavy axis of precip moves in.  The HRRR keeps surface temps at 34-36 though which would be an issue, but I'm guessing it has it's typical bias at play here.

On the other hand, the 3km NAM has the warm nose holding strong until 1-3pm for the northern upstate. It shows surface temps at 32-33 however.

If, if.... somehow the HRRR and ARW thermal profile is right then the northern upstate could get a 4 to 6 inch past job tomorrow as the heaviest rates come through between 10:00am and 3:00pm.   If the 3km NAM is right, then we're going to see a lot of rain/white rain/sleet mix with a possible burst of moderate snow as the back edge swings through with little to no accumulations.

 

It's all comes down to that 800mb warm nose, (and possibly surface temps even if the warm nose is overcome).

I would be really nervous in the Raleigh area as it looks like the warm nose will most likely push in to that area during height of the storm.  Also I wouldn't bank on the precip outlasting the nose on the backside there.  Whoever stays just to north of the warm nose push in that region is going to get 6-10 inches. Whoever is just to the south of it is going to be extremely disappointed. My best guess is Southern Wake gets 1-3 inches of snow/sleet from the storm will the northern end of the county gets the jackpot.

Good analysis Burrel. These systems keep coming through in the middle of the day for the upstate, 6 hours later could have made a world of difference in this case, not just because of time of day but because of timing with cold. Timing is what kept us from getting the totals GA saw back on 2/8 as well. I think the upstate is going to be all over the place with this one, with most seeing no accumulation at all. Pockets that have a hair more cold and less warm nosing could see up to several inches. 

 

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3 minutes ago, burrel2 said:

Sleet will still accumulate at 33-34. I was on the wrong side of a warm nose for a storm a few years ago... the lowest my temp dropped to was 33.1, and started rising from that point and I wound up with an inch and half of sleet that also coated the roads.

Sleet accumulated here last year at 35 or 36 after a couple days in the 70s.

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8 minutes ago, StantonParkHoya said:

If this ends up with less of a warm nose, eastern NC is gonna get pummeled. The qpf is there, just need thermals to cooperate and bust low.

My hope is that as the MHX office says the nam is just too close to the coast with the low. If that can be another 40 to 50 miles south dropping that warm nose back to the southern coastal plains then central eastern coastal plains get more snow less mixing. This is one time we need the low to blend with the amped nam and the suppressed euro and meet in the middle.

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2 minutes ago, shaggy said:

What about PGV? We are flirting with that mix line hard.

That is the ideal spot. MA Handbook reads: be close enough to the mix line to sniff the rain, there shall the big dog eat.

 

Also in the MA Handbook concerning timing of snow: Snow at dark has the most bark, the big possum walks late.

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4 minutes ago, shaggy said:

What about PGV? We are flirting with that mix line hard.

7.8. It looks like we benefit from better ratios. 

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12 minutes ago, mackerel_sky said:

Robert mentions thunder possible tomorrow from ATL,CAE, to CLT in his latest post on FB!

His opening line is comical....there is clearly one state missing in that lineup!  OURS!

The new model data from NAM is in. Snow increases in much more of Tennessee, extreme northern Alabama, extreme northern Georgia and much of North Carolina and much of southern and central Virginia.

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NAM_221_2020021912_F30_36.0000N_79.0000W

NAM_221_2020021912_F33_36.0000N_79.0000W

 

This is essentially I540 between Durham and Raleigh.

Text data shows it still below freezing. Roughly within a half degree.  It's a thin layer but shouldn't see consequence of a warm layer roughly 32-33.

Who knows could be overcome real easy.

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Brad P's latest thoughts. Does a good job of describing the soundings and would probably be helpful to anyone that isn't comfortable reading them.

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1 minute ago, Tony Sisk said:

His opening line is comical....there is clearly one state missing in that lineup!  OURS!

The new model data from NAM is in. Snow increases in much more of Tennessee, extreme northern Alabama, extreme northern Georgia and much of North Carolina and much of southern and central Virginia.

I think northern Pickens and Oconee will get a good snow out of this. 

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Just now, FLweather said:

 

This is essentially I540 between Durham and Raleigh.

Text data shows it still below freezing. Roughly within a half degree.  It's a thin layer but shouldn't see consequence of a warm layer roughly 32-33.

Who knows could be overcome real easy.

Date: 30 hour NAM valid 18Z THU 20 FEB 20
Station: 36.05,-78.96
Latitude:   36.05
Longitude: -78.96
-------------------------------------------------------------------------------
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 1012   135   0.7  -0.1  94  0.9   0.4  36   8 272.9 273.6 272.9 283.0  3.73
  1 1000   230  -0.4  -0.8  97  0.4  -0.5  38  12 272.8 273.4 272.6 282.5  3.61
  2  950   638  -3.4  -4.0  96  0.6  -3.6  45  21 273.8 274.3 272.3 282.0  3.00
  3  900  1065  -3.8  -4.5  95  0.7  -4.1  34  22 277.6 278.1 274.6 286.0  3.04
  4  850  1516  -4.2  -5.1  94  0.9  -4.6  12  13 281.7 282.3 276.9 290.4  3.08
  5  800  1996  -1.5  -1.9  97  0.5  -1.7 181  20 289.6 290.3 282.0 301.6  4.15
  6  750  2512  -1.4  -1.7  97  0.4  -1.6 200  37 295.1 295.9 284.7 308.3  4.49
  7  700  3060  -3.6  -4.1  96  0.6  -3.8 220  37 298.5 299.3 285.5 310.6  4.03
  8  650  3643  -6.5  -7.3  94  0.8  -6.8 229  41 301.6 302.2 286.0 312.0  3.39
  9  600  4264 -10.1 -11.3  90  1.3 -10.5 238  44 304.5 305.0 286.3 312.8  2.68
 10  550  4931 -12.8 -14.4  88  1.6 -13.3 250  53 308.9 309.3 287.5 316.1  2.27
 11  500  5651 -18.2 -20.3  84  2.1 -18.8 252  50 310.8 311.1 287.3 315.8  1.52
 12  450  6430 -22.6 -25.0  81  2.4 -23.1 241  59 314.8 315.0 288.3 318.6  1.11
 13  400  7287 -26.9 -29.5  78  2.6 -27.4 239  81 320.0 320.2 289.6 322.9  0.83
 14  350  8235 -34.1 -37.2  73  3.1 -34.4 244  90 322.8 322.9 290.1 324.4  0.45
 15  300  9300 -41.6 -44.9  71  3.3 -41.8 258 111 326.7 326.8 291.0 327.6  0.23
 16  250 10505 -52.0 -55.8  64  3.7 -52.2 264 120 328.7 328.7 291.5 329.0  0.08
 17  200 11929 -56.3 -72.5  11 16.2 -56.6 274 142 343.5 343.5 295.2 343.6  0.01
 18  150 13754 -56.4 -83.3   2 26.9 -56.7 281 122 372.9 372.9 301.1 372.9  0.00
 19  100 16287 -64.9 -82.1   8 17.3 -65.0 258  89 402.4 402.4 305.5 402.4  0.00
TRP                                             0                              
WND                                             0                          

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Date: 33 hour NAM valid 21Z THU 20 FEB 20
Station: 36.05,-78.96
Latitude:   36.05
Longitude: -78.96
-------------------------------------------------------------------------------
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 1000   215  -0.7                       33  13 272.5                        
  1  950   622  -4.1  -4.8  95  0.7  -4.3  41  27 273.1 273.5 271.6 280.8  2.82
  2  900  1048  -4.3  -5.2  94  0.8  -4.7  32  30 277.0 277.5 274.0 285.0  2.88
  3  850  1497  -5.9  -6.9  92  1.0  -6.2  17  26 280.0 280.4 275.4 287.5  2.67
  4  800  1973  -3.9  -4.3  97  0.4  -4.0 134  14 287.0 287.6 280.0 297.0  3.47
  5  750  2488  -0.8  -1.1  98  0.3  -0.9 185  43 295.7 296.6 285.2 309.7  4.72
  6  700  3037  -2.9  -3.4  96  0.5  -3.1 219  35 299.3 300.1 286.1 312.1  4.25
  7  650  3621  -6.1  -7.0  94  0.8  -6.5 231  37 302.0 302.7 286.3 312.7  3.49
  8  600  4244  -9.1 -10.3  91  1.2  -9.6 244  42 305.5 306.1 286.9 314.6  2.90
  9  550  4913 -12.4 -13.9  89  1.5 -12.9 244  54 309.4 309.8 287.8 317.0  2.38
 10  500  5635 -17.4 -19.3  85  1.9 -17.9 249  58 311.9 312.2 287.9 317.4  1.66
 11  450  6415 -22.4 -24.7  81  2.4 -22.9 239  65 315.1 315.3 288.4 319.0  1.14
 12  400  7272 -27.1 -29.7  78  2.7 -27.5 234  83 319.8 320.0 289.6 322.7  0.81
 13  350  8221 -33.8 -37.0  73  3.1 -34.2 238  97 323.1 323.2 290.2 324.8  0.46
 14  300  9286 -41.4 -44.7  70  3.3 -41.6 251 111 327.1 327.1 291.2 328.0  0.24
 15  250 10493 -51.6                      254 121 329.4                        
 16  200 11920 -55.8                      268 152 344.4                        
 17  150 13733 -59.3                      276 144 367.9                        
 18  100 16265 -63.0                      256  70 406.0                        
TRP                                             0                              
WND                                             0                              

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28 minutes ago, burrel2 said:

Gonna come down to nowcasting for the northern upstate of SC. The HRRR and ARW both have my location's sounding going isothermal around 10am just as the heavy axis of precip moves in.  The HRRR keeps surface temps at 34-36 though which would be an issue, but I'm guessing it has it's typical bias at play here.

On the other hand, the 3km NAM has the warm nose holding strong until 1-3pm for the northern upstate. It shows surface temps at 32-33 however.

If, if.... somehow the HRRR and ARW thermal profile is right then the northern upstate could get a 4 to 6 inch past job tomorrow as the heaviest rates come through between 10:00am and 3:00pm.   If the 3km NAM is right, then we're going to see a lot of rain/white rain/sleet mix with a possible burst of moderate snow as the back edge swings through with little to no accumulations.

 

It's all comes down to that 800mb warm nose, (and possibly surface temps even if the warm nose is overcome).

I would be really nervous in the Raleigh area as it looks like the warm nose will most likely push in to that area during height of the storm.  Also I wouldn't bank on the precip outlasting the nose on the backside there.  Whoever stays just to north of the warm nose push in that region is going to get 6-10 inches. Whoever is just to the south of it is going to be extremely disappointed. My best guess is Southern Wake gets 1-3 inches of snow/sleet from the storm will the northern end of the county gets the jackpot.

Thanks burrel2 for your thoughts. Nam has been on a roll here but I'm rooting against parts of it's over amped solution!

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I ran some quick soundings and didnt find a sleet layer until Sanford. Even then, we're only looking at two layers above freezing and just at 32.3 or so. 

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Just now, BullCityWx said:

I ran some quick soundings and didnt find a sleet layer until Sanford. 

I'm below Sanford in Rockingham, so rain down here?

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Just now, Snow haven said:

I'm below Sanford in Rockingham, so rain down here?

I could see someone from about Wadesboro to Laurinburg getting a few inches of sleet. 

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