griteater

A couple soundings for the archive from Seneca and Gainesville

Yeah I thought the 3km NAM did the best overall with this one. Nice video here of flying locusts from Mike Seidel

GSP NWS has perked up As of 100 AM EST: Much more will follow shortly as the forecast adjustments are underway, but concern for accumulating snow today is growing across northeast Georgia and at least the western Upstate of South Carolina. Water vapor paints the culprit shortwave diving into the lower MS River Valley at this hour. Generally clear skies and excellent radiating conditions over the southeast ahead of this system have permitted cool and dry air to settle into place across the western Carolinas and northeast Georgia. The upstream wave will bring a short window of robust upper jet divergence and deep layer DPVA across the forecast area mainly during the 15Z to 21Z window. The forecast will lean heavily toward the colder NAM profiles as the operational GFS is a warm outlier among the earlier GEFS plumes. Lapse rates will briefly steepen up as well with the passing wave to boost precip rates at times. All told, we are contemplating a Winter Storm Warning across the northeast GA mountains, and an expansion of the Advisory into the mountain valleys and across the western Upstate of SC. Some sort of mix mention will likely be needed in forecast out across the I-77 corridor as well, including the Charlotte metro area. The main lingering question mark is that some mid-level drying wraps into the picture from the WSW this afternoon, and that could undercut ice nucleation and associated snow/accums.

HREF Mean looks like a pretty good compromise. Let's see how it does - https://www.spc.noaa.gov/exper/href/?model=href&product=qpf_001h_mean_ptype&sector=se

We had some of the strongest non-TStorm winds that I can remember late night / early morning....lost power for a few hours

This is simply a very weak upper level wave that tracks roughly from Kansas into TN / NGA. It manages to maximize some low level forcing to generate precip focused across north Bama, north GA, and W SC, before weakening further from there. This system is following right on the heals of the strong system that moved thru yesterday, so it doesn’t have room to amplify and strengthen. With the prevalent southeast ridging, it's pretty much a requirement to get a quick-hitting follow-up system like this for wintry interests...temperatures would warm ahead of any significant system to prevent wintry precip.

Here's the radar simulation on the 3km NAM for the time period between 3AM to 5PM

Model consensus shows precip breaking out over North Bama around 3-4AM. Hitting Gainesville, GA by 9AM. Hitting Greenville, SC by 11AM. Precip window looks to be 3-4 hours. Areas of north GA offer the most promise for some light accumulations based on max forcing and temperatures. Looking at 10pm wet bulb temperatures at Gainesville, GA, the 00z runs of the 3km NAM, 12km NAM, and HRRR are just slightly warmer than the current actual conditions

Spot on post here, especially for N GA into the western upstate. The warm layer is very shallow at the surface on the soundings. The forcing for rising motion is small in aerial coverage, but it maximizes across N GA into the western upstate (850mb warm advection and frontogenesis). These charts actually argue for the ‘heaviest’ snow potential to be south of the mountain areas

It looked like the core of the cell passed along I-85 as you mentioned earlier...so, north of uptown. It's been a frog-strangler here north of town over the past hour

Negative anomaly associated with the 500mb trough is over 5 standard deviations below normal

Here is the Integrated Water Vapor Transport chart showing the large values / large arrows

WPC Excessive Rainfall Discussion... ...Southeast... Widespread heavy rainfall is expected today across much of the Southeast with impressive moisture parameters in place. Both PWs (Precipitable Water) and IVT (Integrated Water Vapor Transport) are around maximum values for early February over the entire Southeast (it is quite impressive to see such a large geographic area with around record values). Thus it seems fair to say that from a moisture and moisture transport perspective you will not see a better setup this time of year than what this event will have to work with.

We’re not even getting into punt formation this winter. We’re throwing pick 6’s and getting strip sacked. Maybe we can pull a late fluke after a lot of warmth like Feb ‘89

Best we could do today (about 30 min ago)

Some large flakes mixing in with the rain in these heavier returns on radar

Light rain with a few flakes mixed in...37 degrees. Looks like this will end up somewhere between the morning 3km NAM and HRRR

Light snow and sleet mix here. It looks like Charlotte will keep the ~140 year streak alive of recording at least a trace of snow each winter

Don't know about in the mtns, but man, out here the NAM has certainly been as good as any model in winter for several years now with it's overall ideas, even at range.

3km NAM sounding at 1PM for Lincolnton, NC

Flakes flying in Brevard on webcam from @Hvward https://www.ashevillewx.com/tj-hooper-nationwide-brevard-live-camera

Go with wet bulb temperatures. You need wet bulb temperatures through the atmosphere to be close to freezing or lower I've seen snow at temperatures as warm as 43, and sleet as warm as 50.

Latest HRRR at 1PM and 2PM today

Latest 3km NAM at 2pm and 3pm today

Widespread snow from Birmingham to Raleigh is quite rare for any month, but the March 1983 storm fits the general narrative