Tn Valley March 4-6 Storm OBS

[ShawnEastTN]

12Z NAM also seems to show the colder air penetrating faster into the moisture with longer duration of frozen precip for all of TN including East Tennessee.

[Stovepipe]

If you look at the last four runs of the NAM you can see the southward movement. My question is, what are your thoughts on this continuing say for example, into the Nashville area?

 

Nashville looks great to me for frozen, no clue how much snow will pan out.  The RAP sim radar is starting to get into range but it should be taken with a grain of salt until 8 hours out or so.  Have to keep an eye on it throughout the day.

 

[ShawnEastTN]

Nashville looks great to me for frozen, no clue how much snow will pan out.  The RAP sim radar is starting to get into range but it should be taken with a grain of salt until 8 hours out or so.  Have to keep an eye on it throughout the day.

 

The RAP seems pretty close to the NAM with the freezing line penetrating pretty far and fast into the precip.

[Stovepipe]

The 12z NAM p-type maps show sleet primarily with some snow on the back end, very little freezing rain at the onset.  It does show all of that changing back over to light rain statewide as it moves out.  No clue if that is accurate.

[jaxjagman]

NAM/WRF 80Km FORECAST FOR: MEM    LAT=  35.05 LON=  -90.00 ELE=   285 TMP

                                     
PRESSURE LEVELS  SFC  1000   950   900   850   800   750   700   650   600     
WED  7A 04-MAR   13    14    14    13    12     9     6     2     0    -3      
WED  1P 04-MAR    8     7     4          10     8     5     3    -1    -3      
WED  7P 04-MAR    0    -1    -5     1     7     6     4     3     0    -4      
THU  1A 05-MAR   -2    -3    -7    -4     2     3     2     2     0    -4      
THU  7A 05-MAR   -4    -6   -10    -9    -4    -2    -1     0    -2    -5      
THU  1P 05-MAR   -3    -6   -10   -10    -6    -3    -2    -3    -5    -7      
THU  7P 05-MAR   -4    -5    -9   -10    -6    -5    -3    -3    -5    -7

 

NAM/WRF 80Km FORECAST FOR: BNA    LAT=  36.12 LON=  -86.68 ELE=   591 TMP

                                     
PRESSURE LEVELS  SFC  1000   950   900   850   800   750   700   650   600     
WED  7A 04-MAR   12    13    10    11    10     8     5     2     0    -4      
WED  1P 04-MAR   10    10     7          10     9     6     2    -1    -4      
WED  7P 04-MAR    2     2    -1    -1     6     6     5     3     0    -3      
THU  1A 05-MAR   -2    -2    -5    -5     0     2     2     1    -1    -4      
THU  7A 05-MAR   -4    -5    -8    -9    -3     0    -1    -1    -1    -5      
THU  1P 05-MAR   -4    -5    -9   -11    -6    -4    -3    -3    -4    -6      
THU  7P 05-MAR   -5    -5    -8   -12    -7    -6    -5    -4    -5    -7

[ShawnEastTN]

The 12z NAM p-type maps show sleet primarily with some snow on the back end, very little freezing rain at the onset.  It does show all of that changing back over to light rain statewide as it moves out.  No clue if that is accurate.

I wonder if that change back over to light rain, is related to diurnal temp fluctuations.  Probably is, I also think that is why it shows the freezing line moving so quickly south and east essentially gobbling up all of the precip across the state during the overnight.

[tnweathernut]

Man, the RGEM just refuses to show much snow in west and parts of middle TN.  It shows quite a bit of sleet (over 1" of QPF northern middle TN), which would total 3 inches of sleet across much of the area around Nashville.

Quite a bit different than some of the other modeling.  It will be fascination to watch this play out.  

Parts of west TN are showing over 6 inches.......................... of sleet, lol.

[jaxjagman]

sref bumped BNA up to 4"..3" for MEM

[ShawnEastTN]

12Z GFS seems to be showing a narrower band of zr, with larger band of snow as it crosses the state, on its ptype map.

[jaxjagman]

The RAP seems pretty close to the NAM with the freezing line penetrating pretty far and fast into the precip.

No warm nose at 700mb on the GFS AT 6Z unlike the NAM showed,it's now down to 800mb 1c,this is for BNA.MEM still is showing the 850-700 mb 1-2C same time

[jaxjagman]

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE NASHVILLE TN
1128 AM CST WED MAR 4 2015

...A WINTER STORM WARNING HAS BEEN ISSUED FOR ALL OF MIDDLE
TENNESSEE...

.A STRONG UPPER LEVEL LOW PRESSURE SYSTEM WILL BRING PLENTY OF
RAIN TO THE MID STATE TODAY...WITH PRECIPITATION CHANGING TO A MIX OF
FREEZING RAIN AND SLEET OVER THE NORTHWEST DURING THE AFTERNOON
HOURS. DURING THE EVENING AND OVERNIGHT...AS COLDER AIR SPREADS
SOUTHWARD...YOU CAN EXPECT THE RAIN TO CHANGE TO A MIX OF FREEZING
RAIN AND SLEET OVER THE REST OF MIDDLE TENNESSEE...AND THEN TO A
MIX OF SNOW AND SLEET OVER MOST AREAS BY LATE NIGHT. THE MAIN
EXCEPTION WILL BE OVER SOME SOUTHERN AREAS...WHERE PRECIPITATION
MAY NOT MIX WITH SNOW UNTIL EARLY THURSDAY MORNING. AREAS NEAR AND
SOUTH OF A LINE FROM CROSSVILLE TO LAWRENCEBURG WILL PROBABLY SEE
WINTRY PRECIPITATION STAY MAINLY IN THE FORM OF SLEET AND FREEZING
RAIN TONIGHT. FOLKS IN THIS AREA...WHERE POTENTIAL IS GREATEST FOR
AN EXTENDED PERIOD OF FREEZING RAIN...SHOULD REMAIN ALERT TO ANY
CHANGE IN THE FORECAST REGARDING ICE ACCUMULATION AS UP TO A
QUARTER OF AN INCH OF ICE IS POSSIBLE.

MOST OF THE AREA IS EXPECTED TO SEE SNOWFALL AND SLEET ACCUMULATIONS
BETWEEN 2 TO 6 INCHES...WITH MOST FREEZING RAIN CAUSING ICE
ACCUMULATION AROUND A TENTH OF AN INCH. AREAS SOUTH OF INTERSTATE
40...ESPECIALLY AREAS NEAR THE ALABAMA BORDER...MAY SEE ICE
ACCUMULATIONS AROUND A TENTH OF AN INCH UP TO A QUARTER OF AN
INCH.

MAJOR TRAVEL IMPACTS ARE EXPECTED TO START DEVELOPING OVER THE
NORTHWEST AND HIGHLAND RIM BY MID TO LATE AFTERNOON TODAY...WITH
TRAVEL CONDITIONS DETERIORATING OVER OTHER AREAS TONIGHT...AS THE
WINTRY PRECIPITATION SPREADS FURTHER TO THE SOUTH AND EAST. IN
FACT...MAJOR TRAVEL IMPACTS WILL LIKELY LAST ALL THE WAY INTO
FRIDAY AFTERNOON SINCE TEMPERATURES ARE EXPECTED TO REMAIN BELOW
THE FREEZING MARK THURSDAY AND MUCH OF FRIDAY. LOW TEMPERATURES
FRIDAY MORNING ARE EXPECTED TO RANGE FROM THE SINGLE DIGITS INTO
THE TEENS.

TNZ056>063-075-077>080-093>095-050600-
/O.UPG.KOHX.WW.Y.0004.150305T0300Z-150305T1800Z/
/O.EXB.KOHX.WS.W.0004.150305T0300Z-150305T1800Z/
PERRY-HICKMAN-LEWIS-WILLIAMSON-MAURY-MARSHALL-RUTHERFORD-CANNON-
BEDFORD-COFFEE-WARREN-GRUNDY-VAN BUREN-WAYNE-LAWRENCE-GILES-
INCLUDING THE CITIES OF...LOBELVILLE...CENTERVILLE...HOHENWALD...
FRANKLIN...BRENTWOOD...COLUMBIA...LEWISBURG...MURFREESBORO...
WOODBURY...SHELBYVILLE...TULLAHOMA...MANCHESTER...MCMINNVILLE...
ALTAMONT...SPENCER...WAYNESBORO...LAWRENCEBURG...PULASKI
1128 AM CST WED MAR 4 2015

...WINTER STORM WARNING IN EFFECT FROM 9 PM THIS EVENING TO NOON
CST THURSDAY...

THE NATIONAL WEATHER SERVICE IN NASHVILLE HAS ISSUED A WINTER
STORM WARNING FOR 1 TO 3 INCHES OF SNOW AND SLEET AS WELL AS UP TO
A QUARTER INCH OF ICE...WHICH IS IN EFFECT FROM 9 PM THIS EVENING
TO NOON CST THURSDAY. THE WINTER WEATHER ADVISORY IS NO LONGER IN
EFFECT.

* TIMING...FROM 9 PM CST WEDNESDAY THROUGH NOON CST THURSDAY.

* ACCUMULATIONS...1 TO 3 INCHES OF SNOW AND SLEET ARE EXPECTED
  WITH THE HIGHEST AMOUNTS CLOSER TO INTERSTATE 40 AND LOWEST
  AMOUNTS NEAR THE ALABAMA BORDER. FREEZING RAIN ACCUMULATIONS
  ARE EXPECTED TO BE AROUND A TENTH OF AN INCH TO A QUARTER OF AN
  INCH...WITH THE HIGHER AMOUNTS OF ICE TO BE FARTHER TO THE
  SOUTH.

* MAIN IMPACT...PRECIPITATION WILL MAINLY BE RAIN DURING THE DAY
  TODAY...THEN MIX WITH FREEZING RAIN AND SLEET DURING THE LATE
  AFTERNOON AND EARLY EVENING. SNOW SHOULD MIX IN WITH THE
  PRECIPITATION IN MOST AREAS OVERNIGHT. THIS MIXED PRECIPITATION
  WILL CREATE MAJOR TRAVEL IMPACTS FROM LATE WEDNESDAY AFTERNOON
  THROUGH FRIDAY AFTERNOON.

* OTHER IMPACTS...TEMPERATURES ARE LIKELY TO STAY BELOW FREEZING
  FROM WEDNESDAY NIGHT THROUGH MID DAY FRIDAY. THIS WILL LIKELY
  KEEP MANY ROADWAYS SLICK AND HAZARDOUS FOR AN EXTENDED PERIOD
  OF TIME.

[ShawnEastTN]

Seems the surface front is now on the doorstep of East Tennessee, and the surface sub-freezing line is now inching into NW TN.  

 

Edit:  If you overlay the radar with the surface temps, the majority of the precip with this is falling from the surface subfreezing line and northwest.  

[ShawnEastTN]

John has your wind switched around up in Campbell county?  Do we have anyone who lives near Union City or Dyersburg on the forum who can keep us posted with OBS?

[nrgjeff]

OHX adding all of Middle Tennessee to the WS Warning kind of tells the story. Looks like more ice accum southern Middle Tenn. Can't argue with more snow northern Middle Tenn. Ground truth in Kentucky, according to EMs and spotters, is a quick trans through freezing rain to sleet and snow. Nashville area snow lovers, wish this is the case down your way too.

 

Memphis better hope that trend holds there because you got a lot of qpf in the hours between surface freezing and whole column freezing. Data points to mostly sleet and snow, so keeping ice glaze at/below .25" seems reasonable.

 

North Alabama and East Tennessee is most interesting. Very back wave behind front now shown with more moisture Thursday morning daylight hours. Models perked up in North Texas and even central Texas with our feature upstream. One would look for that to verify. Wave in question is still digging in the southern Rockies, as of Noon Wednesday.

 

Still the main moisture and robust waves pass over before 12Z Thursday. I have a hard time forecasting ice in Chattanooga post frontal with a weaker last wave like this. The only path is such deep cold air does roll over the Plateau. Look for sleet instead of ZR upstream for Chatty. Knoxvegas has better odds for sleet and snow. Tri Cities is a mess with that 800-700 mb warm layer hanging for so long. Note on model charts valid 12Z Thursday the 850 zero line is under greater than 552 thickness in northeast Tenn. Chart indicates warm air above 850 mb. Should be mainly sleet, not ZR, and still eventually ending as snow TRI. We'll see...

[ShawnEastTN]

Thank you Jeff!  I do wonder about ETN with this storm, generally speaking we don't see much with these but the pressure gradient with that strong High coming down out of the plains makes me wonder if we will actually do better than the average with this set up, and actually get decent spill over the plateau.  I can't wait to watch what happens as the sub-freezing moves against the plateau tonight.  Telling will be how quickly the surface cold makes it from the lower elevations on the west side of the plateau to places like Crossville.  If it makes it pretty rapidly up the plateau then I think spill over will also be much more dramatic than normal from these type of storms.  It'll be fun to watch.

[jaxjagman]

ECMWF Deterministic FORECAST FOR: CHA    LAT=  35.03 LON=  -85.20 ELE=   689

                                            00Z MAR04
                 2 M     2 M     2 M     SFC     SFC    6 HR    FROZN   TOTAL
                 MXT     MNT     TMP     DEW     WIND    QPF     PCP    CLOUD
                 (F)     (F)     (F)     (F)    (KTS)   (IN)    (IN)    (PCT)
WED 00Z 04-MAR                  51.1    49.7    17006                    100   
WED 06Z 04-MAR  55.6    50.0    55.8    55.4    17008   0.06    0.00     100   
WED 12Z 04-MAR  60.6    55.8    60.3    59.8    20008   0.17    0.00     100   
WED 18Z 04-MAR  69.2    60.2    69.5    59.5    22013   0.04    0.00      93   
THU 00Z 05-MAR  71.3    61.2    60.2    55.3    26003   0.04    0.00      97   
THU 06Z 05-MAR  60.3    39.4    39.3    38.5    02008   0.19    0.00     100   
THU 12Z 05-MAR  39.2    31.7    31.2    29.3    00011   0.15    0.04     100   
THU 18Z 05-MAR  31.2    25.4    26.9    18.4    35011   0.23    0.21     100   
FRI 00Z 06-MAR  31.3    25.3    25.6    14.2    01008   0.00    0.00      97   
FRI 06Z 06-MAR  26.2    19.7    20.1     8.8    01008   0.00    0.00       0   
FRI 12Z 06-MAR  20.2    18.7    18.6     5.5    03007   0.00    0.00       2

 

Colder looking now for CHA,euro says so anyways

[John1122]

I haven't gotten nearly the warmth most of you have. It's currently 50 degrees here. Looks like many of you are mid 60s to low 70s.

[jaxjagman]

ECMWF Deterministic FORECAST FOR: TRI    LAT=  36.47 LON=  -82.40 ELE=  1519

                                            00Z MAR04
                 2 M     2 M     2 M     SFC     SFC    6 HR    FROZN   TOTAL
                 MXT     MNT     TMP     DEW     WIND    QPF     PCP    CLOUD
                 (F)     (F)     (F)     (F)    (KTS)   (IN)    (IN)    (PCT)
WED 00Z 04-MAR                  50.4    47.9    20004                    100   
WED 06Z 04-MAR  50.7    48.3    49.4    48.5    20004   0.17    0.00      99   
WED 12Z 04-MAR  52.3    47.3    52.1    51.2    23006   0.10    0.00      99   
WED 18Z 04-MAR  62.3    52.1    62.8    59.4    22008   0.09    0.00      88   
THU 00Z 05-MAR  68.5    47.6    47.2    45.2    01006   0.03    0.00     100   
THU 06Z 05-MAR  47.2    33.1    33.0    31.5    01006   0.11    0.01     100   
THU 12Z 05-MAR  33.0    26.3    25.9    20.7    36009   0.05    0.05     100   
THU 18Z 05-MAR  25.9    19.7    19.6    13.9    35006   0.31    0.30     100   
FRI 00Z 06-MAR  20.3    16.9    16.8    11.2    34004   0.05    0.05     100   
FRI 06Z 06-MAR  16.8    10.2    11.2     2.8    04004   0.00    0.00       3   
FRI 12Z 06-MAR  11.5     4.7     5.3    -5.7    04004   0.00    0.00       1

 

ECMWF Deterministic FORECAST FOR: TYS    LAT=  35.82 LON=  -83.98 ELE=   981

                                            00Z MAR04
                 2 M     2 M     2 M     SFC     SFC    6 HR    FROZN   TOTAL
                 MXT     MNT     TMP     DEW     WIND    QPF     PCP    CLOUD
                 (F)     (F)     (F)     (F)    (KTS)   (IN)    (IN)    (PCT)
WED 00Z 04-MAR                  53.3    51.3    20007                    100   
WED 06Z 04-MAR  57.1    52.1    57.2    56.0    20009   0.07    0.00     100   
WED 12Z 04-MAR  59.0    57.1    59.0    58.1    22010   0.14    0.00      98   
WED 18Z 04-MAR  67.2    59.0    67.5    58.8    22014   0.05    0.00      90   
THU 00Z 05-MAR  69.8    50.2    49.2    48.0    34008   0.15    0.00     100   
THU 06Z 05-MAR  49.3    35.4    35.3    34.7    02007   0.18    0.00     100   
THU 12Z 05-MAR  35.3    27.2    26.9    22.9    01010   0.13    0.09     100   
THU 18Z 05-MAR  26.9    20.8    21.3    15.6    36009   0.29    0.26     100   
FRI 00Z 06-MAR  23.8    17.3    17.0    10.7    03008   0.01    0.01      89   
FRI 06Z 06-MAR  17.3    11.2    13.1     4.8    04007   0.00    0.00       0   
FRI 12Z 06-MAR  13.1    10.3    10.5     0.9    03006   0.00    0.00       0

ECMWF Deterministic FORECAST FOR: CSV    LAT=  35.95 LON=  -85.08 ELE=  1880

                                            00Z MAR04
                 2 M     2 M     2 M     SFC     SFC    6 HR    FROZN   TOTAL
                 MXT     MNT     TMP     DEW     WIND    QPF     PCP    CLOUD
                 (F)     (F)     (F)     (F)    (KTS)   (IN)    (IN)    (PCT)
WED 00Z 04-MAR                  51.4    49.8    19009                    100   
WED 06Z 04-MAR  54.6    51.0    54.7    54.4    19011   0.09    0.00     100   
WED 12Z 04-MAR  58.7    54.7    58.6    58.1    22010   0.28    0.00     100   
WED 18Z 04-MAR  65.0    57.4    61.3    58.4    24008   0.12    0.00      99   
THU 00Z 05-MAR  61.4    38.7    38.3    37.7    35009   0.38    0.00     100   
THU 06Z 05-MAR  38.3    31.5    31.5    29.6    02010   0.23    0.08     100   
THU 12Z 05-MAR  31.5    20.8    20.4    16.9    00012   0.30    0.25     100   
THU 18Z 05-MAR  20.9    16.9    20.6    12.1    35011   0.24    0.23     100   
FRI 00Z 06-MAR  24.1    15.0    14.7     9.5    01009   0.00    0.00      65   
FRI 06Z 06-MAR  14.7     5.4     5.4     1.4    04008   0.00    0.00       0   
FRI 12Z 06-MAR   5.5     0.9     1.0    -3.5    04008   0.00    0.00       0

 

ECMWF Deterministic FORECAST FOR: HSV    LAT=  34.65 LON=  -86.77 ELE=   643

                                            00Z MAR04
                 2 M     2 M     2 M     SFC     SFC    6 HR    FROZN   TOTAL
                 MXT     MNT     TMP     DEW     WIND    QPF     PCP    CLOUD
                 (F)     (F)     (F)     (F)    (KTS)   (IN)    (IN)    (PCT)
WED 00Z 04-MAR                  61.3    59.8    18007                     80   
WED 06Z 04-MAR  63.1    60.9    62.7    62.0    20010   0.08    0.00      98   
WED 12Z 04-MAR  62.7    61.5    61.6    61.1    20009   0.09    0.00     100   
WED 18Z 04-MAR  68.0    61.6    68.1    62.9    21012   0.04    0.00      96   
THU 00Z 05-MAR  70.4    44.1    43.2    42.6    35010   0.36    0.00     100   
THU 06Z 05-MAR  43.2    34.4    34.3    32.6    01009   0.07    0.01     100   
THU 12Z 05-MAR  34.3    25.9    25.7    22.9    36011   0.32    0.17     100   
THU 18Z 05-MAR  27.6    22.0    27.4    18.2    35012   0.24    0.17     100   
FRI 00Z 06-MAR  31.2    22.0    21.6    12.6    00010   0.00    0.00      68   
FRI 06Z 06-MAR  21.6    14.1    14.0     8.1    00010   0.00    0.00       0   
FRI 12Z 06-MAR  14.4    10.9    10.9     4.8    01008   0.00    0.00       1

 

ECMWF Deterministic FORECAST FOR: BNA    LAT=  36.12 LON=  -86.68 ELE=   591

                                            00Z MAR04
                 2 M     2 M     2 M     SFC     SFC    6 HR    FROZN   TOTAL
                 MXT     MNT     TMP     DEW     WIND    QPF     PCP    CLOUD
                 (F)     (F)     (F)     (F)    (KTS)   (IN)    (IN)    (PCT)
WED 00Z 04-MAR                  59.3    57.5    19007                    100   
WED 06Z 04-MAR  61.3    58.7    61.3    60.8    21008   0.11    0.00     100   
WED 12Z 04-MAR  61.9    58.0    58.3    57.6    21005   0.07    0.00     100   
WED 18Z 04-MAR  58.8    42.7    42.7    41.8    36008   0.32    0.00     100   
THU 00Z 05-MAR  42.6    30.4    30.0    28.3    35010   0.57    0.16     100   
THU 06Z 05-MAR  30.0    23.9    23.8    20.6    36010   0.27    0.25     100   
THU 12Z 05-MAR  23.8    18.9    18.8    14.7    01009   0.54    0.50     100   
THU 18Z 05-MAR  25.7    18.2    26.1    12.7    35009   0.08    0.08      90   
FRI 00Z 06-MAR  28.4    16.9    16.3     9.6    35009   0.00    0.00       1   
FRI 06Z 06-MAR  16.3     6.0     5.9     2.8    00008   0.00    0.00       0   
FRI 12Z 06-MAR   5.9    -1.1    -1.0    -4.3    02007   0.00    0.00       0   
FRI 18Z 06-MAR  27.1    -1.2    27.6    13.3    02001   0.00    0.00       0   
SAT 00Z 07-MAR  33.6    27.0    27.7    18.4    24002   0.00    0.00       0   
SAT 06Z 07-MAR  27.8     8.7     8.7     4.2    20007   0.00    0.00       0   
SAT 12Z 07-MAR   9.8     7.5     8.1     3.9    20008   0.00    0.00       0

 

 

ECMWF Deterministic FORECAST FOR: MEM    LAT=  35.05 LON=  -90.00 ELE=   285

                                            00Z MAR04
                 2 M     2 M     2 M     SFC     SFC    6 HR    FROZN   TOTAL
                 MXT     MNT     TMP     DEW     WIND    QPF     PCP    CLOUD
                 (F)     (F)     (F)     (F)    (KTS)   (IN)    (IN)    (PCT)
WED 00Z 04-MAR                  60.2    58.6    20006                    100   
WED 06Z 04-MAR  60.3    56.7    60.3    59.2    20009   0.00    0.00      92   
WED 12Z 04-MAR  61.9    56.9    56.6    56.2    33005   0.16    0.00     100   
WED 18Z 04-MAR  56.7    41.1    40.6    39.1    01012   0.22    0.00     100   
THU 00Z 05-MAR  40.6    25.4    25.2    22.3    02014   0.61    0.26     100   
THU 06Z 05-MAR  25.2    21.7    21.6    17.6    02016   0.58    0.39     100   
THU 12Z 05-MAR  21.6    19.2    19.3    14.2    01012   0.35    0.31     100   
THU 18Z 05-MAR  28.0    19.3    28.2    12.1    01011   0.02    0.02       0   
FRI 00Z 06-MAR  29.7    20.4    19.6    11.2    01008   0.00    0.00       0   
FRI 06Z 06-MAR  19.6     8.5     8.3     3.0    05009   0.00    0.00       0   
FRI 12Z 06-MAR   8.3     1.3     1.3    -2.8    07008   0.00    0.00       0

[jaxjagman]

[John1122]

John has your wind switched around up in Campbell county?  Do we have anyone who lives near Union City or Dyersburg on the forum who can keep us posted with OBS?

My winds are out of the north at 9 currently.

[jaxjagman]

 

 

MESOSCALE DISCUSSION 0114
   NWS STORM PREDICTION CENTER NORMAN OK
   0134 PM CST WED MAR 04 2015

   AREAS AFFECTED...NRN ARKANSAS...SRN MISSOURI...SRN ILLINOIS...WRN
   KENTUCKY...NWRN TENNESSEE

   CONCERNING...HEAVY SNOW

   VALID 041934Z - 042330Z

   SUMMARY...HEAVY SNOW...AT RATES OF 1 TO 2 INCHES PER HOUR...APPEARS
   POSSIBLE WITHIN A DEVELOPING BAND...FROM THE BOSTON MOUNTAINS OF
   NORTHWEST ARKANSAS EAST NORTHEASTWARD ACROSS THE MISSOURI BOOTHEEL
   AND ADJACENT PORTIONS OF THE LOWER OHIO VALLEY THROUGH 00-01Z.

   DISCUSSION...SLOW...STEADY SOUTHWARD ADVANCEMENT AND DEEPENING OF
   THE SURFACE BASED COLD INTRUSION IS EXPECTED TO CONTINUE THIS
   AFTERNOON ACROSS THE OZARK PLATEAU AND MIDDLE MISSISSIPPI
   VALLEY...COINCIDENT WITH THE CONTINUED EASTWARD PROGRESSION OF THE
   LARGE...POSITIVELY TILTED NORTHERN STREAM UPPER TROUGH.  THE LATEST
   RAPID REFRESH AND NCEP SREF OUTPUT SUGGEST THAT COOLING OF A REMNANT
   WARM LAYER BETWEEN 850 MB AND 700 MB WILL BE ACCOMPANIED BY THE
   CONTINUED TRANSITION OF PRECIPITATION TO ALL SNOW ACROSS THE
   REMAINDER OF SOUTHERN MISSOURI INTO NORTHERN ARKANSAS THROUGH THE
   21-23Z TIME FRAME.  AT THE SAME TIME...STRENGTHENING LOWER/MID
   TROPOSPHERIC FRONTOGENETIC FORCING FOR UPWARD VERTICAL MOTION IS
   EXPECTED TO SUPPORT INTENSIFYING PRECIPITATION RATES.  IT APPEARS
   THAT THIS WILL BE ENHANCED BY FORCING IN THE RIGHT ENTRANCE REGION
   OF A HIGH LEVEL JET OVERSPREADING THE REGION...INCREASING LIFT
   WITHIN THE FAVORABLE MIXED PHASE LAYER FOR LARGE DENDRITIC ICE
   CRYSTAL GROWTH.  GIVEN THE AVAILABLE MOISTURE /PW ON THE ORDER OF
   .50-.75 INCHES/ WHICH CONTINUES TO RETURN ON THE NORTHERN PERIPHERY
   OF SUBTROPICAL RIDGING...IT APPEARS THAT A HEAVY SNOW BAND...AT
   RATES OF 1-2 INCHES PER HOUR...MAY EVOLVE THROUGH EARLY
   EVENING...WHILE TENDING TO DEVELOP EAST NORTHEASTWARD TOWARD THE
   LOWER OHIO VALLEY.

 

[ShawnEastTN]

MRX dropped the Watch for most of the remaining counties under it and put up a WWA for all of East TN.  They upgraded to warnings central and southern plateau counties.  

 

Interesting read between the two advisories.  WWA issued for calling for up to a .1 of an inch of ZR, and less than 2" of snow sleet.  Then neighboring central plateau counties under WSW up to .25 ZR, and less than an inch of snow sleet.  Seems they think plateau counties at least central and southern plateau counties will get more ZR, and less snow sleet, and higher potential for more snow/sleet in the valley.

[John1122]

Apparently MRX thinks tomorrow could be a little more snowy for the Valley and points East.

 

 

 

MODELS SNOW FALL OUTPUT AND CURRENT FORECAST
MAY BE UNDERDONE FOR MID DAY THURSDAY FOR CENTRAL VALLEY AND E
AREAS. WEAK LIFR REMAINS INTO THE EARLY AFTERNOON WITH MODEST
AVAILABLE MOISTURE. TEMPERATURES WILL FALL THROUGH THURSDAY.

[1234snow]

Amazing temp contrast across the Tri-Cities. 73 in Johnson City and 40's in SWVA. My car read 41 earlier where there is snowpack. 53 at my house. Flooding has been a issue today and the main show isn't even here yet.

[1234snow]

[nrgjeff]

MRX dropped the Watch for most of the remaining counties under it and put up a WWA for all of East TN.  They upgraded to warnings central and southern plateau counties.  

 

Interesting read between the two advisories.  WWA issued for calling for up to a .1 of an inch of ZR, and less than 2" of snow sleet.  Then neighboring central plateau counties under WSW up to .25 ZR, and less than an inch of snow sleet.  Seems they think plateau counties at least central and southern plateau counties will get more ZR, and less snow sleet, and higher potential for more snow/sleet in the valley.

 

Thanks for the props earlier. MRX may be thinking about the warm layer above 850 mb from 800-700 mb. Plateau at a higher elevation puts less cold air between surface and the warm layer. Valley floor has thicker cold air - if it can get over the Plateau in time. On paper is makes sense, but we will find out tomorrow.

 

Though most of the system(s) depart(s) by 12Z that last piece coming from North Texas and arriving in East Tennessee in the morning is key. If cold air really makes it over the Plateau in time qpf confidence is pretty good. We sent Texas the Volunteers. Will they send East Tenn one last winter show?

 

Oh 18Z NAM says back to reality - cold chasing rain southeast Tenn. It goes with a more southern track out of central Texas. Watch actual events in Texas to see if 18Z is a fluke or a quality update.

[GeneR4]

I love it, it's 74 here and under a Winter Storm Warning(primarily for Ice).  Also, the Gov declared another State of Emergency for AL.

[ShawnEastTN]

Thanks for the props earlier. MRX may be thinking about the warm layer above 850 mb from 800-700 mb. Plateau at a higher elevation puts less cold air between surface and the warm layer. Valley floor has thicker cold air - if it can get over the Plateau in time. On paper is makes sense, but we will find out tomorrow.

 

Though most of the system(s) depart(s) by 12Z that last piece coming from North Texas and arriving in East Tennessee in the morning is key. If cold air really makes it over the Plateau in time qpf confidence is pretty good. We sent Texas the Volunteers. Will they send East Tenn one last winter show?

 

Oh 18Z NAM says back to reality - cold chasing rain southeast Tenn. It goes with a more southern track out of central Texas. Watch actual events in Texas to see if 18Z is a fluke or a quality update.

That makes perfect sense!  It would be nice to have one last little snow event before climatology beats winter out of the picture.  I'm certainly happy to have less odds of ZR after the last couple ice storms.  Still have trees to cut up on my property from damage.

[1234snow]

Who likes green and pink?

[WestTennWX]

John has your wind switched around up in Campbell county?  Do we have anyone who lives near Union City or Dyersburg on the forum who can keep us posted with OBS?

 

Just made the drive home from work in Western Kentucky-  around a tenth of an inch of zr- then a quick changeover to some of the hardest sleet I have ever experienced. Some flash freezing of the rain on the roads, temp at 29 at my place here in UC now. Sleet quickly accumulating, will upload some pics a little later as long as I have power.