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Wintry 2/11-2/12 ULL Magic or More Cold Rain

metwannabe said:
Happy for y'all if this verifies but not gonna lie, it also stings a little lol

GFS deep south with snow, GA in play on this run

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I will literally fall over Niagara Falls (Canadian side) in a barrel if this verifies. Yes I'm optimistic buuuttt.. Either way this is some serious eye candy!!
 
packfan98 said:
3” mean for RDU on the 6z GEFS. Strong signal!
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Yeah you dont wanna be the jackpot until Sat morning, still 3-4 days out....

A few degrees warmer or colder in the column going to have big implications of who gets what where....when it closes off, how strong it actually gets, how far south does it get, when does it turn NE etc etc etc a lot of things can and will change.
 
GSP
LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 325 am EST Wednesday: ***Potential increasing for significant
wintry precip across the mountains over the weekend.*** A very
active pattern will continue for much of the extended period over
the Southeast, as a series of short wave troughs/upper lows is
expected to impact the region. Global model guidance is converging
toward a strong consensus regarding the first of these over the
weekend, as an already-potent...and still intensifying...upper low
will likely be centered over the lower Miss Valley at the start of
the period, and is expected to sweep across the Deep South through
the end of the weekend. Resultant coastal cyclogenesis will likely
bring another round of precip near...and quite possibly into the CWA
from late Saturday through early Sunday. The devil will be in the
details re: p-type...and those details are far from clear at this
point...with the presence of any cold air available to interact
with frontogenetical forcing and deformation zone depending upon
the cyclone track and the cyclone`s intensity/ability to crank up
the cold advection to its west. Based upon the latest guidance, this
looks to be a rain/snow scenario for the time being, and we will
continue to side with climatology and a ballpark consensus of
thermodynamic profiles to keep any snow mention confined to the
mountains...and primarily above 3000` or so at that. However, there
remains plenty of time for this forecast to go sideways in either
direction.
 
GSP says no snow below 3000 feet. Only snow this weekend will be in the mountains. That was earlier this morning. Guess they were a little shocked at the 06z run when it came out and showed accumulating snow for all of their cwa
 
Cad Wedge NC said:
GSP says no snow below 3000 feet. Only snow this weekend will be in the mountains. That was earlier this morning. Guess they were a little shocked at the 06z run when it came out and showed accumulating snow for all of their cwa
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Today is scramble day for the NWS offices. They’re running out of models to point to that show what their above words say.
 
Peachtree City GA
.LONG TERM...
(Thursday night through Tuesday)
Issued at 337 AM EST Wed Feb 8 2023

What looked to be a warm, clear, comfortable weekend as of yesterday
morning`s forecast package, has now rapidly diverged into a
cool/cold, wet and cloudy weather setup. This change comes as the
shortwave impulse that will affect the weather pattern in Georgia
this weekend recently coming onshore in the Pacific Northwest
over the last 6-18 hours with better upper air sampling.

Prior to Saturday the forecast remains on track with a cold front
slowing down across NW Georgia Friday morning, if not outright
stalling. Southwesterly flow will manifest as a warm, moist conveyer
belt ahead of the frontal boundary which with PWATs increasing to
1.5+ inches will provide widespread, continuous rain showers through
Friday. As the front picks up steam and pushed southeastward late
Friday, added convergence along the frontal boundary combined with
peak moisture flux should elevated rain totals in the southern and
eastern portions of the forecast area where average QPF totals are
now exceeding 2.5 inches in some isolated locations.

The biggest change, however, is with the progression and evolution
of a secondary shortwave, which was supposed to lift towards the
northeast and progress the broader wavetrain, but now looks to cut
off and swing through the Southeastern Gulf states through the
weekend. Despite the rapid changes to the systems evolution, the
consistency among the models on the upper-level and surface system
placements is uncanny, which did add confidence in the rapid change
to our forecast package. As the upper-level cutoff low pushes
eastward, a surface low is forecast to form along the baroclinic
boundary along the eastern coastline and sit off the Georgia
coastline by Saturday afternoon evening. With colder air
infiltrating the forecast area on the backside of the low
temperatures should begin to drop through the weekend, setting up
for potential wintry weather in the southern Appalachians on Saturday
night through Sunday morning. GFS has been aggressive with heavy
dendritic growth falling as melting snow in these areas but other
models have been a tiny bit more progressive and dry so exact
details will have to be worked out as the system approaches, but
signals for a couple inches of snow are increasing for the higher
elevations above 2000ft and are worth monitoring going forward.
Additionally, with temperatures just above freezing models might
tell two different stories between how much snow could FALL, versus
how much snow could STICK, therefore model interpretation will be
key. (That`s why us meteorologists make the moderate bucks!)
 
Blue_Ridge_Escarpment said:
Today is scramble day for the NWS offices. They’re running out of models to point to that show what their above words say.
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Yeah it’s a little bit interesting that even with now pretty much all OP models and their ensembles supporting some snowfall for at least most of their forecast area, they aren’t at least suggesting a little more in their discussions. Obviously they are leaning on the overall pattern right now which says the odds are quite low
 
We’ve really improved our BL issues somewhat. Models are responding to the ULL taking control and where we had temps in the upper 30’s you’re seeing runs with surface temps around 33-34 with freezing surface temps just south of I40. We also have a small CAD setup with a nice little 1028-1030 HP sliding in ahead and during the initial storm to help cool the climb even more. That’s something you want to continue.
 
NWS RKE not biting yet.

.LONG TERM /SUNDAY THROUGH TUESDAY/...
As of 220 AM EST Wednesday...

Drier and warmer for early next week...

On Sunday the closed low moving across the Deep South will skirt
our area to the south and move offshore Monday. This system
presents the best chance for precipitation over the next 7 days,
although most of the rain will mainly be over NC and eastern
VA.
 
IF only the 6z GFS could get one right inside a 100 hours. I'd write a check for this to be the time. It can't trend any better for Triad. Gotta hold serve for 4 more days , what could possibly go wrong LOL!!!

Thats Old school Tree Snapper. Reminds me of Feb 28,2004 ULL that dumped 17.5 IMBY
 
Despite all the pretty 10:1 SLR maps from the GFS suite, I'm still having a hard time seeing how this works out in a big way for areas outside the mountains. I still can see some snow for sure, but I think it's going to be a very sloppy, low-end event in the best case scenario here.

I can't find any really good examples where an upper low totally cut off from the mean flow like this & crushed the piedmont + coastal plain. Cut off upper lows are fine but you usually still need at least a little injection of cold air continuing to funnel into the ULL.

This is a composite of 15 upper low cases I could find since the 1950s that actually worked out for folks east of the mountains. Notice the ridge anomaly to the west of the cut-off over the Upper Midwest & southern Canada helping to keep some injection cold air going into the base of this cut-off upper low.
compday.sWanlKp64c.gif



Notice in our setup however, the ridge completely comes over the top and basically shuts off the tap of cold air from the north & you're having to rely entirely on precipitation rates to cool the column to freezing. If you're hoping for a big snow outside the mountains, this pattern isn't a good one for setups like these.


ecmwf-ensemble-avg-namer-z500_anom_1day-6224800.png
 
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