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Deleted member 1449
Guest
The 6Z NAM keeps surface temps around 31 at GSO all day Thursday.
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Wintry Feb 17-19 Smastsmasher Snow/Ice
- Thread starter SD
- Start date
Webberweather53
Meteorologist
6z NWS Blend of Models FRAM. Concerning to see >0.25" of ice being spit out 3 days in advance. I'm hoping this event's higher precip rates will be a saving grace here & cut back on ZR totals more than the models are leading on. The blue ridge escarpment in northern NC & southern VA is probably screwed, that 0.5-0.6" you're seeing just north of Mt Airy.
RAH has changed their tune:
Unfortunately, the wedge of colder air will likely result in another
round of frozen precipitation for parts of the region as another low
pressure system develops in the Gulf of Mexico and moves northeast
towards the Carolinas. The setup is definitely similar to what
happened over the weekend, although once again there is some
uncertainty with how cold surface temperatures will be. Have trended
the temperatures in the direction of the (colder) NAM which
typically handles CAD situations the best. Temperatures aloft will
be warm enough that snow will not be a threat anywhere, and the
surface cold layer will be thin enough to prevent refreezing above
the surface, leaving rain and freezing rain as the only expected
precipitation types.The high pressure to the north will be well
situated to provide reinforcing cold air, but this system appears to
produce higher precipitation amounts than the last one. Between the
higher amounts of precipitation that are forecast (which could
translate into higher freezing rain amounts) and lasting impacts
from the last round of ice, have decided to issue a Winter Storm
Watch for some northern counties. However, a much larger area is
under the threat for receiving at least a glaze of ice, reaching all
the way down to Asheboro and Raleigh. Precipitation is likely to
move in after midnight Thursday and persist for at least 24 hours
before winding down by Friday morning. There is quite a bit of
uncertainty in just how wide a range high temperatures will be on
Thursday between varying model solutions. The Triad may barely rise
above freezing while Sampson County will likely reach 60 degrees.
Similarly, there will be a decent spread in temperatures Thursday
night, ranging from the freezing mark to the mid 40s.
Unfortunately, the wedge of colder air will likely result in another
round of frozen precipitation for parts of the region as another low
pressure system develops in the Gulf of Mexico and moves northeast
towards the Carolinas. The setup is definitely similar to what
happened over the weekend, although once again there is some
uncertainty with how cold surface temperatures will be. Have trended
the temperatures in the direction of the (colder) NAM which
typically handles CAD situations the best. Temperatures aloft will
be warm enough that snow will not be a threat anywhere, and the
surface cold layer will be thin enough to prevent refreezing above
the surface, leaving rain and freezing rain as the only expected
precipitation types.The high pressure to the north will be well
situated to provide reinforcing cold air, but this system appears to
produce higher precipitation amounts than the last one. Between the
higher amounts of precipitation that are forecast (which could
translate into higher freezing rain amounts) and lasting impacts
from the last round of ice, have decided to issue a Winter Storm
Watch for some northern counties. However, a much larger area is
under the threat for receiving at least a glaze of ice, reaching all
the way down to Asheboro and Raleigh. Precipitation is likely to
move in after midnight Thursday and persist for at least 24 hours
before winding down by Friday morning. There is quite a bit of
uncertainty in just how wide a range high temperatures will be on
Thursday between varying model solutions. The Triad may barely rise
above freezing while Sampson County will likely reach 60 degrees.
Similarly, there will be a decent spread in temperatures Thursday
night, ranging from the freezing mark to the mid 40s.
PARSONBROWN
Member
Map?
Webberweather53
Meteorologist
NWS RAH has issued winter storm watches for the Triad & Roxboro for the potential of a significant ice storm later this week.
HSVweather
Member
Webberweather53
Meteorologist
Many areas of northern NC & southern VA are still without power from last week's ice storm. The lingering effects from this ice storm combined w/ saturated soils from recent persistent, heavy rainfall are pretty worrisome imo, because it will lower the amount of ice required to bring down trees & power lines.
NCSNOW
Member
Canadian Models continue To advertise freezing rain throughout:
6z Nam12k
3k only goes out to hr 60 and it would advertise More as precip is still on going
6z Nam12k
3k only goes out to hr 60 and it would advertise More as precip is still on going
NCSNOW
Member
NCSNOW
Member
This is begining Precip me/packfan on RGEM
Nam Begining Precip; Trended colder 6z, but Not to Regem levels yet. splitting hairs, probably meet in middle.
Nam Begining Precip; Trended colder 6z, but Not to Regem levels yet. splitting hairs, probably meet in middle.
NCSNOW
Member
This is getting interesting. A few things to track today; of course the models (high setup --> if more Classic than in-situ CAD), the amount of dry air being and forecasted to filter in before the event (there are model dew point differences of upper teens to mid 20s), and of analysis from our on board mets (Webber,Delta) and NWS discussions.
EMTime
Member
Wsw out for my area. I've never seen one issued here less than a day after another one.
It may have happened but I certainly don't remember it.
It may have happened but I certainly don't remember it.
NCSNOW
Member
6zNam is 1031 HP, 12zEuro 1033, 6zRGEM 1034. That will be important to watch. Its placement and how long it stays anchored as well. They have the location same spot
ICON held on to its solution .. i don’t like how FRAM is already at the point it is .. that happened day of last storm but now it’s happening a day or so out so the more time we have the worse this could trend
iGRXY
Member
NAM trended well south with the freezing rain at 6z. We are just now in its wheelhouse with another 24 hours of potential south or north trends before it really locks on a solution. For the upstate it’s the ICON/NAM/CMC/RGEM vs the GFS and Euro. So basically the models that handle CAD better vs the ones that don’t but are still borderline.
Webberweather53
Meteorologist
As usual, the RGEM is too cold this morning over areas w/ snow cover in Texas & Oklahoma. If you're entrusting this model to try & forecast sfc temps over NC tomorrow night & Thursday morning, good luck to you...
RGEM forecast vs 12z obs:
KOKC (Will Rogers World Airport): 6z RGEM: -15°F vs 12z obs: -6°F; RGEM bias: -9°F
KMFE (McAllen Miller Int'l Airport): 6z RGEM: 19°F vs 12z Obs: 27°F; RGEM bias: -8°F
KDFW (Dallas-Ft Worth Int'l Airport): 6z RGEM: -6°F vs 12z Obs: 1°F; RGEM bias: -7°F
KIAH (Bush Intercontinental/Houston Airport): 6z RGEM: 7°F vs 12z obs: 13°F; RGEM bias: -6°F
KAUS (Austin-Bergstrom Int'l Airport): 6z RGEM: 2°F vs 12z obs: 8°F; RGEM bias: -6°F
KSPS (Wichita Falls Regional Airport): 6z RGEM: -8°F vs 12z obs: -3°F; RGEM bias: -5°F
KACT (Waco Regional Airport): 6z RGEM: -3°F vs 12z obs: 2°F; RGEM bias: -5°F
KTXK (Texarkana Regional Airport): 6z RGEM: -4°F vs 12z obs: 1°F; RGEM bias: -5°F
RGEM forecast vs 12z obs:
KOKC (Will Rogers World Airport): 6z RGEM: -15°F vs 12z obs: -6°F; RGEM bias: -9°F
KMFE (McAllen Miller Int'l Airport): 6z RGEM: 19°F vs 12z Obs: 27°F; RGEM bias: -8°F
KDFW (Dallas-Ft Worth Int'l Airport): 6z RGEM: -6°F vs 12z Obs: 1°F; RGEM bias: -7°F
KIAH (Bush Intercontinental/Houston Airport): 6z RGEM: 7°F vs 12z obs: 13°F; RGEM bias: -6°F
KAUS (Austin-Bergstrom Int'l Airport): 6z RGEM: 2°F vs 12z obs: 8°F; RGEM bias: -6°F
KSPS (Wichita Falls Regional Airport): 6z RGEM: -8°F vs 12z obs: -3°F; RGEM bias: -5°F
KACT (Waco Regional Airport): 6z RGEM: -3°F vs 12z obs: 2°F; RGEM bias: -5°F
KTXK (Texarkana Regional Airport): 6z RGEM: -4°F vs 12z obs: 1°F; RGEM bias: -5°F
Dewpoint Dan
Member
Seems like it's actually colder in some areas than the RGEM says. -19 in Northwest Arkansas and -13 in Tulsa.
Webberweather53
Meteorologist
Even for the models that handle CAD better you're still talking about temps ~33-34F in/around GSP. Need to see them drop another 4F to have any serious issues in the upstate, and even if ice occurs it's likely going to be on elevated sfcs, the ground temps are warm and will likely keep many of the area roads just wet, not to mention the rates will be higher for this storm. It's much easier to get temp changes in a CAD setup in the short-range when you're well above freezing, but changes usually asymptote once you get to 32F as the offsetting effect from latent heat release makes it really hard to get significantly under the freezing mark in reality and on the models without more substantial changes to the setup.
Webberweather53
Meteorologist
For the most part, the RGEM is too cold region-wide, as it often is.
MichaelJ
Member
Yeah I don't buy the RGEM for Temps and think the NAM does a much better job with them. At this point I am not even looking at the globals except for some ensemble runs. If the NAM verifies, it could save us in the Triad if the precip is of a heavier nature added to 31-32 degree temps and moderate precip causing less ice accrual on power lines and roads. This would lead to say 100,000 without power instead of 1,000,000 if it trends colder
NWS in Blacksburg seems to have backed off, at least with the wording compared to last nights forecast for Wednesday night/Thursday. Wording not nearly as threating!
They did have sleet and snow to start in the forecast now Rain with a chance of freezing rain, I guess expecting temps to be a little warmer low 30s now forecasted where they was saying a low of 30. Big difference in 30 vs 32 when it comes to freezing rain.
They did have sleet and snow to start in the forecast now Rain with a chance of freezing rain, I guess expecting temps to be a little warmer low 30s now forecasted where they was saying a low of 30. Big difference in 30 vs 32 when it comes to freezing rain.
ajr
Member
Ugh — we already have flood warnings in my area.
Blue_Ridge_Escarpment
Member
Going to be pretty dang cold tonight, in the teens, and not much climbing tomorrow. Another ingredient for a significant ice storm.
Webberweather53
Meteorologist
For now, 0.1-0.2" seems like a good conservative first-guess in Winston, out of respect for the potentially high precip rates that could warm many up to freezing or just below it and slow ice accrual. Northern Guilford & pts north to the VA border look primed to see at least 0.2" again...
Webberweather53
Meteorologist
The northern Blue ridge escarpment is screwed.
Yup, It's seems to always be a degree or two off!
Tarheelwx
Member
RGEM looks to be busting too warm in CAD areas this morning. 06z run has GSO getting down to 26 on Thursday morning. I think maybe yesterday this time, the RGEM showed GSO bottoming out around 28-29 on Thursday morning. Now, the NAM has GSO bottoming out at 30 and the GFS gets down just below 30. So while the RGEM may be a bit overzealous with the wedge and it's impact, the other models have trended to where it was a day or two ago. So, there is some merit there. At this stage, all I'm looking for is trends in surface temps, wet bulbs, hp strength, hp location, temp trends in NoVa/PA, and temp trends where the hp is centered today Having said all that.
D
Deleted member 1449
Guest
The 6Z EURO is a long duration event for the Triad (except it warms above freezing for a time during the day Thursday): Freezing rain--rain--freezing rain.
Webberweather53
Meteorologist
RGEM had GSO bottoming out at 27F yesterday's 6z run, it's showing 26F now. Basically no change overall and no cold trend. Again, it's likely gonna be too cold, usually is for CAD. Other models often trend towards its solution but that doesn't necessarily make it right because it busts too low a majority of the time.
D
Deleted member 1449
Guest
Round one:
Snowman63
Member
It's got Memphis at 2° and we actually made it to 1°.
D
Deleted member 1449
Guest
Round two:
EMTime
Member
My local met here said he doesn't think the models are handling the shallow cold air that's already in place very well, and that he feels we will get sleet or freezing rain again for NE Ms and nw Alabama.
Webberweather53
Meteorologist
Again, a few locations it's close to or warmer than forecast, but when you actually compare the model temps to observed, they are too cold at a majority of locations region-wide.
packfan98
Moderator
Yuck! Do you have ice totals?
Tarheelwx
Member
Poimen - do you have a storm total for zr for the triad from the 06 Euro?
TW
TW
D
Deleted member 1449
Guest
As far as I can tell weathermodels.com does not include the ice accumulation parameter for the EC (at least the 6Z).
Webberweather53
Meteorologist
WPC 50th percentile ice accumulation forecast.
chapelhillwx
Member
You are right but I am pretty amazed at how close it is in Arkansas relative to the RGEM forecast. Happened to grab this screenshot for posterity this morning.
