South/Southeast Snow chances..
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- Stormsfury
- Category 5
- Posts: 10549
- Age: 53
- Joined: Wed Feb 05, 2003 6:27 pm
- Location: Summerville, SC
South/Southeast Snow chances..
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- Stormsfury
- Category 5
- Posts: 10549
- Age: 53
- Joined: Wed Feb 05, 2003 6:27 pm
- Location: Summerville, SC
-
- Tropical Storm
- Posts: 234
- Joined: Sun Dec 07, 2003 8:05 pm
- Location: yorktown, va
- Contact:
snow setup
Possible back to back punch for SE VA
Monday's system
MON 1am http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_042l.gif
MON 7am
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_048l.gif
MON 1pm
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_054l.gif
Total liquid amount
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_054l.gif
Tues 1pm
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_078l.gif
Tues 7pm
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_084l.gif
Wed 1am
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_090l.gif
Total liquid amounts
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 8_096l.gif
Monday's system
MON 1am http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_042l.gif
MON 7am
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_048l.gif
MON 1pm
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_054l.gif
Total liquid amount
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_054l.gif
Tues 1pm
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_078l.gif
Tues 7pm
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_084l.gif
Wed 1am
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_090l.gif
Total liquid amounts
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 8_096l.gif
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- Stormsfury
- Category 5
- Posts: 10549
- Age: 53
- Joined: Wed Feb 05, 2003 6:27 pm
- Location: Summerville, SC
Wow, look at that! Hey, I'll just take 1" of snow...
or, 2"...
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NASHVILLE TN
117 PM CST SAT FEB 14 2004
TNZ005>011-022>034-056>066-075-077>080-093>095-151030-
BEDFORD-BENTON-CANNON-CHEATHAM-CLAY-COFFEE-CUMBERLAND-DAVIDSON-
DEKALB-DICKSON-FENTRESS-GILES-GRUNDY-HICKMAN-HOUSTON-HUMPHREYS-
JACKSON-LAWRENCE-LEWIS-MACON-MARSHALL-MAURY-MONTGOMERY-OVERTON-PERRY-
PICKETT-PUTNAM-ROBERTSON-RUTHERFORD-SMITH-STEWART-SUMNER-TROUSDALE-
VAN BUREN-WARREN-WAYNE-WHITE-WILLIAMSON-WILSON-
117 PM CST SAT FEB 14 2004
THIS HAZARDOUS WEATHER OUTLOOK IS FOR MIDDLE TENNESSEE.
.DAY ONE...TONIGHT
A SNOW ADVISORY IS IN EFFECT FOR MUCH OF MIDDLE TENNESSEE FOR
LATE TONIGHT. SNOW IS EXPECTED TO DEVELOP OVER THE MID STATE TOWARD
SUNRISE...WITH SOME ACCUMULATION POSSIBLE.
.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY
A SNOW ADVISORY IS IN EFFECT FOR SUNDAY FOR MUCH OF MIDDLE
TENNESSEE...WITH ONE TO THREE INCHES OF ACCUMULATION EXPECTED
BY EARLY SUNDAY AFTERNOON.
ROADWAYS ACROSS THE ADVISORY AREA WILL LIKELY BECOME SLICK AND
HAZARDOUS. BE ESPECIALLY CAUTIOUS WHEN CROSSING BRIDGES AND
OVERPASSES. IF YOU ARE PLANNING TO TRAVEL ACROSS THE MID STATE
...YOU SHOULD MONITOR THE LATEST WEATHER INFORMATION AS THIS
SITUATION DEVELOPS.
OUTSIDE OF THE ADVISORY AREA...OVER NORTHWESTERN AND EXTREME
SOUTHERN MIDDLE TENNESSEE...UP TO AN INCH OF SNOW ACCUMULATION
IS POSSIBLE BY SUNDAY AFTERNOON.
.SPOTTER INFORMATION STATEMENT...
ACTIVATION OF EMERGENCY MANAGERS AND SPOTTERS GROUPS IS NOT
ANTICIPATED.
or, 2"...

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NASHVILLE TN
117 PM CST SAT FEB 14 2004
TNZ005>011-022>034-056>066-075-077>080-093>095-151030-
BEDFORD-BENTON-CANNON-CHEATHAM-CLAY-COFFEE-CUMBERLAND-DAVIDSON-
DEKALB-DICKSON-FENTRESS-GILES-GRUNDY-HICKMAN-HOUSTON-HUMPHREYS-
JACKSON-LAWRENCE-LEWIS-MACON-MARSHALL-MAURY-MONTGOMERY-OVERTON-PERRY-
PICKETT-PUTNAM-ROBERTSON-RUTHERFORD-SMITH-STEWART-SUMNER-TROUSDALE-
VAN BUREN-WARREN-WAYNE-WHITE-WILLIAMSON-WILSON-
117 PM CST SAT FEB 14 2004
THIS HAZARDOUS WEATHER OUTLOOK IS FOR MIDDLE TENNESSEE.
.DAY ONE...TONIGHT
A SNOW ADVISORY IS IN EFFECT FOR MUCH OF MIDDLE TENNESSEE FOR
LATE TONIGHT. SNOW IS EXPECTED TO DEVELOP OVER THE MID STATE TOWARD
SUNRISE...WITH SOME ACCUMULATION POSSIBLE.
.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY
A SNOW ADVISORY IS IN EFFECT FOR SUNDAY FOR MUCH OF MIDDLE
TENNESSEE...WITH ONE TO THREE INCHES OF ACCUMULATION EXPECTED
BY EARLY SUNDAY AFTERNOON.
ROADWAYS ACROSS THE ADVISORY AREA WILL LIKELY BECOME SLICK AND
HAZARDOUS. BE ESPECIALLY CAUTIOUS WHEN CROSSING BRIDGES AND
OVERPASSES. IF YOU ARE PLANNING TO TRAVEL ACROSS THE MID STATE
...YOU SHOULD MONITOR THE LATEST WEATHER INFORMATION AS THIS
SITUATION DEVELOPS.
OUTSIDE OF THE ADVISORY AREA...OVER NORTHWESTERN AND EXTREME
SOUTHERN MIDDLE TENNESSEE...UP TO AN INCH OF SNOW ACCUMULATION
IS POSSIBLE BY SUNDAY AFTERNOON.
.SPOTTER INFORMATION STATEMENT...
ACTIVATION OF EMERGENCY MANAGERS AND SPOTTERS GROUPS IS NOT
ANTICIPATED.
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- wx247
- S2K Supporter
- Posts: 14279
- Age: 41
- Joined: Wed Feb 05, 2003 10:35 pm
- Location: Monett, Missouri
- Contact:
Annette is probably going to get snow! YAY! 

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Personal Forecast Disclaimer:
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.
- Erica
- Professional-Met
- Posts: 168
- Joined: Sat Feb 14, 2004 2:45 am
- Location: Daytona Beach, FL
- Contact:
Nice catch, SF. Lets take a look at 500mb heights and vorticity valid at 9z and 12z on Sunday morning.
9z
12z
The closed low at 500mb would imply good PVA ahead of the vort, and the development of strong UVM throughout the column, in the deformation zone. The figure below depicts 850mb UVM (Upward Vertical Motion).
850mb UVM
500mb UVM
Notice the strong UVM and negative Omegas throughout a deep layer. This is a good sign when looking for maximized snowfall growth, and the most out of the available QPF.
this all however, assumes that dynamical cooling will be able to overcome the warm layers aloft, to produce snowfall, if not, then precipitation type remains rain.
the sounding at HSV (Huntsville, AL) would not support any type of frozen precipitation at 9z. However as the low progresses east-northeast, the strong UVM will encounter the North Georgia mountains, and the southern appalachains. These are the areas which could see quite a bit of snowfall, then that area will continue east into North Carolina and Southern Virginia.
As we get down to 27 hours (21z Sunday) the best UVM will have moved into the carolinas, where temperature profiles are a bit more acceptable for widespread snowfall.
Here's ETA 850mb temps valid 21z Sunday.
850mb UVM
500mb UVM
300mb UVM
The ETA implies that UVM should be fairly strong through a deep layer of the atmosphere, but in order to determine if snowfall growth will be maximized, we have to see where the best UVM and RH are located in relatioship to the -12 to -15C layer of the column.
The 0z Sounding at DAN (Danville, VA) showed an above freezing boundary layer, and a slightly anove freezing temps below 968mb in the lowest few Hundred meters above the surface. Otherwise, the sounding implied some convective instability and CSI signal, with dry Adiabatic lapse rates, and weak elevated CAPE.

9z

12z

The closed low at 500mb would imply good PVA ahead of the vort, and the development of strong UVM throughout the column, in the deformation zone. The figure below depicts 850mb UVM (Upward Vertical Motion).
850mb UVM

500mb UVM

Notice the strong UVM and negative Omegas throughout a deep layer. This is a good sign when looking for maximized snowfall growth, and the most out of the available QPF.
this all however, assumes that dynamical cooling will be able to overcome the warm layers aloft, to produce snowfall, if not, then precipitation type remains rain.
the sounding at HSV (Huntsville, AL) would not support any type of frozen precipitation at 9z. However as the low progresses east-northeast, the strong UVM will encounter the North Georgia mountains, and the southern appalachains. These are the areas which could see quite a bit of snowfall, then that area will continue east into North Carolina and Southern Virginia.
As we get down to 27 hours (21z Sunday) the best UVM will have moved into the carolinas, where temperature profiles are a bit more acceptable for widespread snowfall.
Here's ETA 850mb temps valid 21z Sunday.

850mb UVM

500mb UVM

300mb UVM

The ETA implies that UVM should be fairly strong through a deep layer of the atmosphere, but in order to determine if snowfall growth will be maximized, we have to see where the best UVM and RH are located in relatioship to the -12 to -15C layer of the column.
The 0z Sounding at DAN (Danville, VA) showed an above freezing boundary layer, and a slightly anove freezing temps below 968mb in the lowest few Hundred meters above the surface. Otherwise, the sounding implied some convective instability and CSI signal, with dry Adiabatic lapse rates, and weak elevated CAPE.
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- Stormsfury
- Category 5
- Posts: 10549
- Age: 53
- Joined: Wed Feb 05, 2003 6:27 pm
- Location: Summerville, SC
- Stormsfury
- Category 5
- Posts: 10549
- Age: 53
- Joined: Wed Feb 05, 2003 6:27 pm
- Location: Summerville, SC
- Stormsfury
- Category 5
- Posts: 10549
- Age: 53
- Joined: Wed Feb 05, 2003 6:27 pm
- Location: Summerville, SC
Outstanding post, Erica ... back in MS/AL, there are likely to be locations that will pick up accum. snowfalls even if SFC temperatures remain barely ABV FRZ, and the enhancement from potential CSI, and a deformation zone setting up. Again, with such cold temperatures just ABV the SFC (950mb and up, espc. behind the H5 low), heavier (and in this case, convective precip) will drag down colder air and draw this down to the SFC (just like a summertime storm) ...
And again, the model guidance doesn't handle dynamical cooling and CSI banding well ... and generally, completely misses, and fools many forecasters as well ... which can be attributed to some of the busts in the Southland/Southeast on many occasions in the past ...
And again, the model guidance doesn't handle dynamical cooling and CSI banding well ... and generally, completely misses, and fools many forecasters as well ... which can be attributed to some of the busts in the Southland/Southeast on many occasions in the past ...
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- Erica
- Professional-Met
- Posts: 168
- Joined: Sat Feb 14, 2004 2:45 am
- Location: Daytona Beach, FL
- Contact:
To get CSI and banding, you need negative EPV above a sloping frontal bundary. If were looking at Convecitve instability, theta-e drops with height, and dry adiabatic lapse rates are required, above 6.00 C/km. Some SCAPE ( Slantwise CAPE) can also help. But I Don't have BUFKIT installed so i can't tell whether or not there is any elevated CAPE for sure.
Last edited by Erica on Sat Feb 14, 2004 9:14 pm, edited 1 time in total.
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- Stormsfury
- Category 5
- Posts: 10549
- Age: 53
- Joined: Wed Feb 05, 2003 6:27 pm
- Location: Summerville, SC
Erica wrote:To get CSI and banding, you need negative EPV above a sloping frontal bundary. If were looking at Convecitve instability, theta-e drops with height, and dry adiabatice lapse rates are required, above 6.00 C/km. Some SCAPE ( Slantwise CAPE) can also help. But I Don't have BUFKIT installed so i can't tell whether or not there is any elevated CAPE for sure.
I do, but I'm having some issues with running it sometimes, especially when I'm updating my website ... so I'm not absolutely sure myself ...
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- Erica
- Professional-Met
- Posts: 168
- Joined: Sat Feb 14, 2004 2:45 am
- Location: Daytona Beach, FL
- Contact:
Stormsfury wrote:Erica wrote:To get CSI and banding, you need negative EPV above a sloping frontal bundary. If were looking at Convecitve instability, theta-e drops with height, and dry adiabatice lapse rates are required, above 6.00 C/km. Some SCAPE ( Slantwise CAPE) can also help. But I Don't have BUFKIT installed so i can't tell whether or not there is any elevated CAPE for sure.
I do, but I'm having some issues with running it sometimes, especially when I'm updating my website ... so I'm not absolutely sure myself ...
I'm going to install it tomorrow actually, I haven't gotten around to it since we have GEMPAK. So I mostly use that instead. It's the easiest way to make cross-sections, and display pretty much any paramater at any different level. Really great software though, I think. But you need to have Linux.
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