Jump to content
  • Member Statistics

    17,588
    Total Members
    7,904
    Most Online
    LopezElliana
    Newest Member
    LopezElliana
    Joined

Jan 22-23 East Coast Storm Discussion


Wow

Recommended Posts

  • Replies 3.5k
  • Created
  • Last Reply

Something to keep in mind is the Warmer SST anomalies resultant from the Warmest December on record and of course the warm fall. This will certainly factor in as far as SLP strength, coastal front warmth (east winds/changeover to sleet/zr/rain), etc... This could potentially lead to more mixing, more dynamically driven snow/sleet/freezing, more icentropic lifting, thundersnow, wind, etc. Will be fun to watch the SLP strength tomorrow. Also if the below map is correct, i would favor the SLP on that SST boundary just offshore the carolinas. Some of the models have taken it right up the that line. 

 

cdas-sflux_ssta_watl_1.png

Link to comment
Share on other sites

Thanks Phil!  Always nice to see you stop by   :wub:

 

No problem. I always like to say hello from time to time with the southeast crew. Really these forums and threads were where I got a lot of my knowledge from back in high school and undergrad so its nice to return and see how all the mets and locals alike are doing :)

 

Anyway to add a little bit of info from some of the latest higher resolution guidance:

 

Things could ramp up fairly quickly tomorrow morning for those in WNC and upstate SC... where a lot of the high resolution guidance is suggesting a laterally translating band to develop across the area before 12z. This will probably precede a lot of the stronger WAA aloft, so this might be a chance for upstate SC to pick up a quick few inches of snow before things change over to sleet as the warm nose kicks in. Note how the 850-hPa frontogenesis is aligned from NW SC into the midlands of NC. That is providing the mesoscale forcing for ascent that will probably lead to high precipitation rates even early on in the event. 

 

URL: http://www.atmos.albany.edu/student/ppapin/lb13_img/hrrr/hrrr_ncep_fgen_all_alb.php

 

850-hPa Frontogenesis from HRRR

 

GOyhB6o.png

 

Corresponding 1km Reflectivity... strongest reflectively nicely corresponds to the intense frontogenesis band. 

 

KroSnID.png

 

12z Sounding near KGSP... with only a weak warm nose, it may be just cold enough for wet snow around this time:

 

HCRbTrU.png

 

Afterwards though... the majority of the snowfall will probably be confined to the WNC mountains and nearby foothills... that warm nose is going to come in quite quickly behind this initial band, and there is pretty high confidence things will change over to sleet/freezing rain in upstate SC.

 

By 17z things should be all sleet/freezing rain at KGSP per the 3km NCAR ensemble... note the clear 4-6C warm nose by all of the ensemble members around 850-hPa.

 

URL: http://www.image.ucar.edu/wrfdart/ensemble/sounding.php?d=2016012100 (choose location near KGSP)

 

zMriVum.png

 

The hardest to predict area will be between WNC mountains and Raleigh... where the warm nose will be battling the strongest CAD induced cooling. That early morning band could prove to be quite important, as if things can dynamically cool quickly from higher precipitation rates, it may allow locations further east to stay snow for a little longer before things switch over. There is high uncertainty on how far west the warm nose gets in NC... as exhibited by high temp uncertainty near KGSO into Friday evening. 

 

WbcTD3s.png

 

That is crazy uncertainty from NCAR between ensemble members that don't have a warm nose > 0C at 850hPa, all the way to several that have warm noses getting up to 6-7C at 850hPa. This is where the battleground is set for tomorrow, and where the snow/sleet line will continue to oscillate back and forth as precipitation rates wax and wane. Folks south and east of KGSO probably will have a significant to majority period of sleet/freezing rain occurring, while locations further north and west of KGSO will likely have a longer period of snow. 

 

Anyway... probably enough discussion for now. Let's see how everything unfolds shall we :)

Link to comment
Share on other sites

Doppler how much do you really buy into these?? Just curious if they should be taken with a grain of salt.

no way we get 1.6" qpf as snow, but it shows the possibility (albeit small) that we can get a good initial thumping of snow.  3-5" seems about right basd on the latest model trends.  hrrr and rap have us waking up to heavy snow that will accumulate quickly.

Link to comment
Share on other sites

no way we get 1.6" qpf as snow, but it shows the possibility (albeit small) that we can get a good initial thumping of snow.  3-5" seems about right basd on the latest model trends.  hrrr and rap have us waking up to heavy snow that will accumulate quickly.

 

The 18z GFS COBB output showed 5.9" SN for RDU, plus sleet, FWIW.

Link to comment
Share on other sites

dewpoint at 23 currently.

Someone else posted Charlotte dewpoints were surprisingly low. I'm hoping that is the wedge showing up. High dewpoints in the upstate are concerning me. 44/34 here, that will not allow the upstate to wet bulb down. I'm looking for the wedge to change that. Needs to happen soon but NEGA and upstate are obviously last ones to get the cooling.

Link to comment
Share on other sites

Kirk Mellish with wsbradio calling for around an inch for NE burbs. I'm not holding my breath, I think we're just on the wrong side of this tight gradient. Still fun to watch the panic though!

Yeah, I'm not liking the shift slighty north and less organized of th 500mb LP.  We should score a flizzard I hope.

Link to comment
Share on other sites

18z GEFS from dt facebook

attachicon.gifimage.png

This is actually the "High-Resolution GEFS."

 

DT has been posting it for a while, and it's been holding very steady with snowfall accumulation amounts for a while now, though it has shifted south slightly. All of that isn't snow by a long shot, but that's still a lot of snow/sleet/freezing rain.

Link to comment
Share on other sites

Someone else posted Charlotte dewpoints were surprisingly low. I'm hoping that is the wedge showing up. High dewpoints in the upstate are concerning me. 44/34 here, that will not allow the upstate to wet bulb down. I'm looking for the wedge to change that. Needs to happen soon but NEGA and upstate are obviously last ones to get the cooling.

 

 

I was almost exactly the same around 4:00 pm today and am currently sitting at 31.8/26, so the wedge is definitely building in.

 

That also makes me wonder about what the HRRR and RAP are currently forecasting.  Below is the composite reflectivity with precip type and 2m temps for 3 am tonight.  I am right at the Mecklenburg and Union county borders and these show precip starting as rain, and temps around 34/35.  Well I am already lower than that and my wet bulb is 29.5, so I dont see how this ends up being correct.  RAP is nearly the same.  

 

And while the station closest to me is a little cooler than most, nearly all are 37 degrees or less.  Excluding some of the big outliers in the 40's.  So I would think even if that station was a couple degrees too cold, places at 37 would still be way below 34/35 at 3 am???

 

Temps

 

post-7405-0-06762400-1453424165_thumb.pn

 

Precip

 

post-7405-0-95090600-1453424175_thumb.pn

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...