Significant winter storm to unfold for Southern half of

air360 · #21 Postby **air360** » Sat Dec 25, 2004 7:27 pm

i agree with everything you are saying wxguy25...it is all making sense but what im wondering is when will the NWS jump on board..i hate their "all rain" forecast!!

rainstorm · #22 Postby **rainstorm** » Sat Dec 25, 2004 7:30 pm

6-8 looks likely in vab

yoda · #23 Postby **yoda** » Sat Dec 25, 2004 7:31 pm

I hope the models move the storm like 100 miles west... I know I am -removed-, but still... I WANT MY SNOW!!! LOL... :lol:

Stormsfury · #24 Postby **Stormsfury** » Sat Dec 25, 2004 7:33 pm

air360 wrote:i agree with everything you are saying wxguy25...it is all making sense but what im wondering is when will the NWS jump on board..i hate their "all rain" forecast!!

Winter storms in the Southeast in this fashion are ALWAYS difficult, if not impossible to forecast due to ...

1) lack of RAOB observations where the resultant player originates
2) which causes skewed/flawed datasets, and no one can blame model guidance on that b/c simply of the lack of data.
3) many forecasters overlook the synoptic setup and dismiss threats until almost go time b/c of reasons 1 and 2.
4) complex patterns don't usually yield significant winter weather events such as this one.

SF

#25 Postby **Lowpressure** » Sat Dec 25, 2004 7:35 pm

Westward has been the trend and Wakefield thinks it will move more westward based on the current structure and movement in the Gulf coast area. DP jumped from 10 to 18 here. I am with you Yoda, 100 miles more!! In my case maybe 50 will do the trick.

SunnyThoughts · #26 Postby **SunnyThoughts** » Sat Dec 25, 2004 7:37 pm

Yoda...My daughter is in DC visiting her boyfriend...she was suppose to come back to Florida yesterday...but alas..her plane was delayed and she wouldn't be able to make her connection in Atlanta, so she stayed on in DC until tomorrow..(the first flight she could get) She so wanted to see snow up that way...because lets face it..that doesn't happen often here. It hasn't snowed at ALL the entire week she's been up there. I wouldn't doubt in the last as soon as her plane takes off..the snow will start in earnest...thats just her luck bless her.

air360 · #27 Postby **air360** » Sat Dec 25, 2004 7:40 pm

if the SE is lucky enough to get a big dump she could see some from the plane looking out the window as well...but *sigh* its not the same...that is to bad...hopefully it can get up there fast enough to where she can have a few min. in it!

#28 Postby **Lowpressure** » Sat Dec 25, 2004 7:45 pm

SunnyThoughts wrote:Yoda...My daughter is in DC visiting her boyfriend...she was suppose to come back to Florida yesterday...but alas..her plane was delayed and she wouldn't be able to make her connection in Atlanta, so she stayed on in DC until tomorrow..(the first flight she could get) She so wanted to see snow up that way...because lets face it..that doesn't happen often here. It hasn't snowed at ALL the entire week she's been up there. I wouldn't doubt in the last as soon as her plane takes off..the snow will start in earnest...thats just her luck bless her.

What time is her flight, and what airport? Snow is slated to start in Fredericksburg around noon, so National should get snow 1-2 p.m. Dulles is more inland, and unless track moves more west ( which it has trended), would get less snow. Obviously based on track and speed of storm.

#29 Postby **wxguy25** » Sat Dec 25, 2004 7:49 pm

Stormsfury wrote:
wxguy25 wrote:We'll call it blasted, w/ mixed precip then snow.

http://weather.unisys.com/eta/30h/eta_700_30h.gif

Look at those UVV values at 30hrs off the NC coast of > 15 microbars/second. There you are likely getting a combination of WAA, DPVA and jet dynamics which are leading to the strong upward motion. BOTTOM LINE -- its going to get ugly along the NC/VA coast (in a good way though!)

hmmm...about the only thing that may save us down here from a major icestorm ...

SF

It will depend on the depth of the warm layer as to whether or not the dynamics will be able to produce enough adiabatic cooling to offset it. Based on the 18z ETA sounding sat Florence, my best guess would be that p-type begins as SN /IP mix then changes to +ZRA as the flow turns E / SE off the ocean and the highest UVM overspreads the region. Boundary layer temps are marginal but once again the models are probably underestimating that. The depth of the warm layer is pretty large and temps reach almost +5 C so I don’t think the UVM will be able to sufficiently offset that to allow for SN but you will see +IP mix in at times during the heavier bursts. Weak elevated CAPE is present as well which would help to increase convective potential.

The CHS sounding favors mostly Rain based on thickness values, but again this is probably too warm.

air360 · #30 Postby **air360** » Sat Dec 25, 2004 7:55 pm

wxguy25 wrote:... The depth of the warm layer is pretty large and temps reach almost +5 C so I don’t think the UVM will be able to sufficiently offset that to allow for SN but you will see +IP mix in at times during the heavier bursts...

does this mean an all rain event with maybe a little mixture...or did i misunderstand you in that paragraph talking abotu somethign else?

colawx · #31 Postby **colawx** » Sat Dec 25, 2004 7:56 pm

Stormsfury,
Yes we spoken in WWBB and I have been reading here for sometime. I always look for your post. They seem to always be so accurate. I hope that you get all of the snow you want. I hope that we don't have an icestorm up here. Last year's storm in Columbia caused us to be without power for a week.

SunnyThoughts · #32 Postby **SunnyThoughts** » Sat Dec 25, 2004 7:57 pm

Lowpressure, she's leaving out of dulles at about 11:40 am...but she's currently staying about 45 NW of there.

SunnyThoughts · #33 Postby **SunnyThoughts** » Sat Dec 25, 2004 7:57 pm

oops 45 minutes NE of there.

#34 Postby **wxguy25** » Sat Dec 25, 2004 8:00 pm

air360 wrote:
wxguy25 wrote:... The depth of the warm layer is pretty large and temps reach almost +5 C so I don’t think the UVM will be able to sufficiently offset that to allow for SN but you will see +IP mix in at times during the heavier bursts...

does this mean an all rain event with maybe a little mixture...or did i misunderstand you in that paragraph talking abotu somethign else?

SN to rain situation for you probably.

Stormsfury · #35 Postby **Stormsfury** » Sat Dec 25, 2004 8:03 pm

It will depend on the depth of the warm layer as to whether or not the dynamics will be able to produce enough adiabatic cooling to offset it. Based on the 18z ETA sounding sat Florence, my best guess would be that p-type begins as SN /IP mix then changes to +ZRA as the flow turns E / SE off the ocean and the highest UVM overspreads the region. Boundary layer temps are marginal but once again the models are probably underestimating that. The depth of the warm layer is pretty large and temps reach almost +5 C so I don’t think the UVM will be able to sufficiently offset that to allow for SN but you will see +IP mix in at times during the heavier bursts. Weak elevated CAPE is present as well which would help to increase convective potential.

The CHS sounding favors mostly Rain based on thickness values, but again this is probably too warm.

Or a dry slot ... based on satellite, dry slot may be heading into the region Sunday morning, BUT at the same time, radar trends continue to show redevelopment of precipitation along the southern portions of the where the cutoff is.

As for Soundings, CHS stated that the thickness schemes are too warm (in a phone convo earlier this afternoon) and stated in their ZFP, they expect IP mix as far south as Highway 17 (only a few miles from the coast) ...

Temperatures already have fallen to 36º at the airport (TD - 34º), and already 34º here, with some IP mixing with rain...

SF

Stormsfury · #36 Postby **Stormsfury** » Sat Dec 25, 2004 8:04 pm

colawx wrote:Stormsfury,
Yes we spoken in WWBB and I have been reading here for sometime. I always look for your post. They seem to always be so accurate. I hope that you get all of the snow you want. I hope that we don't have an icestorm up here. Last year's storm in Columbia caused us to be without power for a week.

I remember that icestorm, and probably one of my biggest forecast successes WRT to the depth of the CAD signature and overall synoptic recognition. That was one of the worst icestorms in at least 30 years.

SF

#37 Postby **wxguy25** » Sat Dec 25, 2004 8:21 pm

Actually check out the squall line thats developing ahead of the vorticity maximum off of the FL coast.
Something tells me we may be in for a shocker here...

http://www.goes.noaa.gov/GSSLOOPS/ecwv.html

EDIT -- and the 01z RUC has analyzed the SLP at 1002mb.

Stormsfury · #38 Postby **Stormsfury** » Sat Dec 25, 2004 8:32 pm

wxguy25 wrote:Actually check out the squall line thats developing ahead of the vorticity maximum off of the FL coast.
Something tells me we may be in for a shocker here...

http://www.goes.noaa.gov/GSSLOOPS/ecwv.html

EDIT -- and the 01z RUC has analyzed the SLP at 1002mb.

Noticed that ... whoa ... my links haven't updated the 1z RUC as of yet.. will try the SPC RUC make your own source ...

SF

Stormsfury · #39 Postby **Stormsfury** » Sat Dec 25, 2004 8:34 pm

UVV's at or lower than -15 over Savannah, GA as of the 1z initialization. yikes!!

SF

air360 · #40 Postby **air360** » Sat Dec 25, 2004 8:38 pm

im having a stupid moment...what are UVV's

Significant winter storm to unfold for Southern half of

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