Blue Ridge

The National Weather Service in Morristown has issued a * Severe Thunderstorm Warning for... Northwestern Knox County in east Tennessee... Anderson County in east Tennessee... Southeastern Campbell County in east Tennessee... Union County in east Tennessee... * Until 1145 AM EDT. * At 1057 AM EDT, a severe thunderstorm was located near Clinton, moving northeast at 55 mph. HAZARD...60 mph wind gusts. SOURCE...Radar indicated.

2019 is going to continue doing 2019 things, so it stands to reason this winds up a nothingburger. That said, it's fun to track what may well be the last severe threat of the year for the fer east valley. Some clearing is now visible on GOES East; meanwhile, winds have really cranked up at TYS.

SPC expanded the ENH risk southwestward across the far, far northeastern tip of Johnson County. Upper East TN is in 5% TOR. Any severe weather today will be a matter of threading the needle. MRX sees the LLJ ramping up as a primary catalyst, assuming downsloping does its job and warms the area ahead of the area of showers to the west. The best chance appears to be after this current lobe of moderate rain moves out and the dry area currently north and east of Chattanooga envelops the area. This may allow for warming and an increase in instability.

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF SOUTHERN PENNSYLVANIA SOUTHWARD INTO NORTHERN NORTH CAROLINA... ...SUMMARY... Severe thunderstorms capable of strong wind gusts are expected across much of the eastern U.S. Thursday -- particularly from areas along and east of the central and southern Appalachians to the mid Atlantic and Carolinas coastal areas. ...Synopsis... An upper trough crossing the central U.S. at the start of the period will evolve into a deepening closed low with time, as the system shifts quickly east-northeastward across the Midwest, and then into the Northeast overnight. As this occurs, the broader trough surrounding the low will gradually take on a more neutral to slightly negative tilt, through the end of the period. As this occurs, a cold front -- initially trailing from a low near the KY vicinity southward across Alabama to near the mouth of the Mississippi River -- will advance steadily eastward during the day. The front should cross the Appalachian crest by afternoon, as the parent low rapidly deepens and eventually occludes over the Lower Great Lakes area, reaching the Atlantic coast after midnight. This front will focus a band of showers and thunderstorms -- and attendant risk for severe weather primarily along and east of the mountains. ...Portions of the PA/NY vicinity southward/southwestward to the southern Appalachians... A zone of showers and thunderstorms should be ongoing at the start of the period from the mid Ohio Valley/Mid South region south-southwestward to the western Gulf of Mexico, in the vicinity of an advancing surface cold front. A secondary area of showers -- perhaps with some embedded lightning -- will be shifting quickly northeastward across the Carolinas/Virginia vicinity. Only minimal severe risk -- mainly in the form of gusty winds or a brief tornado -- is apparent at this time within either of these areas of convection through the first several hours of the period. With time, the advance of the cold front across the southern, and then the central, Appalachians during the afternoon in conjunction with the strengthening upper system will result in gradual organization of a band of frontal convection. Very strong flow aloft will aid in the convective organization, with upscale evolution toward a semi-continuous band of storms expected. By late afternoon/early evening, storms will likely have become fairly well-organized, crossing south-central and southeastern PA, MD, VA, and the Carolinas along with attendant risk for strong/damaging wind gusts. Low-level wind profiles will become supportive of supercells during the afternoon across the pre-frontal warm sector. While suggestive of some tornado potential, pre-frontal warm-sector storms are largely not anticipated. Still, a few mainly QLCS-type tornadoes will be possible, given the overall dynamic/kinematic set-up -- particularly from late afternoon through mid evening. As storms near the coast overnight, gradual weakening of the convection -- and associated diminishing of the severe risk -- is expected, though limited wind risk will likely extend to near the mid Atlantic/Carolina coasts overnight. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 30% - Enhanced Hail: 5% - Marginal

Breezing through the 12z runs, some of the short-range/hi-res models look pretty interesting across the Appalachian Highlands. I'll leave the analysis to the experts, but the supercell composite and STP in particular caught my eye. Seems like most/all are in agreement on a somewhat potent squall line racing through tomorrow evening; whether discreet cells can form ahead of the line is another story. Eagerly awaiting the 1730 SPC Day 2 update.

Full disclosure: don't consider myself a Vols fan, though I do watch with interest. Certainly not an apologist. SEC Network's Jordan Rodgers posted on Twitter a great breakdown that more or less proves JG called his own shot on the botched QB sneak. Likely would have been a TD had the play been run as called. He also missed a wide open Jauan Jennings earlier in the game for a sure TD. Had Maurer not been injured, I think the game plays out differently. Bama could say the same about Tua, however. Zebras also got in the way. Absolutely atrocious officiating all night. I think Pruitt/Chaney will do well if given a bit more time. To hear him talk, Pruitt sounds like a dolt, but playcalling and effort have improved greatly throughout the season. Sit Maurer for the rest of the season. Fire JG into the sun. Start Shrout and throw in the wildcat with Jennings or Jordan. The season is already lost, but I see good things coming. If Maurer looks good, QB debate gets interesting next season between him and the Maryland transfer Kasim Hill.

and within 240? My god. Sound the alarms.

Looks like the nasty cell that flared up between Newport and Parrottsville verified its SVR. MRX received a report of 1.5" hail in Greene County.

It's lol-worthy at this point.

That's...not good.

Yeah, no. Doesn’t work like that, buddy. I experienced the same issue as @Windspeed. A similar issue was previously noted on AmWx some time ago. Sometimes it’s the result of malicious script injected w/o the webmaster’s knowledge; other times, an ad can be the culprit. Perhaps don’t be quite so abrasive in the future.

Darwinism at work... In other news, we took a long drive around rural Washington and Greene Counties. Limestone Creek is doing a number on north and west sections of Washington Co. I’ll post pics in a bit.

Noticed the same thing earlier wrt FFWs. In fact, Knox Co does not show a FFW despite the PDS Warning in place.

If anything, this may have just a bit of wiggle room to move slightly north and still train directly over Knoxville proper. TYS is going to be oh so close.

The train is arriving, and I’ll let the storm tracks tell the story. Stay safe, Knoxville friends.

It's going to be a photo finish. Storm tracks on KOHX are also showing slightly more ENE than NE. Watch the training cells move just south of McMinnville. From a hobbyist standpoint, this is fascinating to watch. Meanwhile, the stream in my front yard is slowly beginning to grow into a pond.

Easy, dude. @janetjanet998 has been instrumental in flood coverage since this risk first presented itself. Also, we don't "stick to areas" here. The warning you referred to is an areal flood warning. Not the same as a Flash Flood Warning, and certainly not given the same priority. FFWs trigger EAS.

Two notes, FWIW. 1) There appears to be westerly forcing pushing some of the training cells in middle TN more eastward. This is visible on KHTX. Watch the push around the 50nmi band. Pure conjecture without the aid of a sounding: flow aloft may be more from the west than south, pushing the higher-topped convection east while flow in the lower levels pushes more north. Just a thought. https://weather.cod.edu/satrad/nexrad/index.php?type=HTX-N0Q-0-6 2) Not sure I see much opportunity for clearing across the moderate risk area. That said, that's some nice convection moving into the Arklatex... https://weather.cod.edu/satrad/exper/?parms=regional-southeast-truecolor-24-1-100-1&checked=map&colorbar=undefined

Can't say I've seen an area go from no FFW to a PDS Flash Flood Emergency in one fell swoop.

...FLASH FLOOD EMERGENCY FOR KNOXVILLE TENNESSEE AND GREATER KNOX COUNTY... The National Weather Service in Morristown has issued a * Flash Flood Warning for... Knox County in east Tennessee... * Until 130 PM EST. * At 1036 AM EST, emergency management reported heavy rain across the warned area. Up to 3 inches of rain have already fallen over the last 3 to 4 hours with an additional 1 to 2 inches possible over the next 2 hours. Flash flooding is already occurring. This is a FLASH FLOOD EMERGENCY for Knoxville. This is a PARTICULARLY DANGEROUS SITUATION. SEEK HIGHER GROUND NOW!

After missing out on all but drizzle yesterday, I woke up to 1.63" and a rushing stream in my front yard. I don't so much as have a ditch line.

PRELIMINARY LOCAL STORM REPORT...SUMMARY NATIONAL WEATHER SERVICE MORRISTOWN TN 346 PM EST WED FEB 20 2019 ..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON... ..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE.... ..REMARKS.. 0700 AM NON-TSTM WND GST COVE MOUNTAIN 35.71N 83.59W 02/20/2019 M87 MPH SEVIER TN MESONET 0630 AM NON-TSTM WND GST CAMP CREEK 36.09N 82.77W 02/20/2019 M81 MPH GREENE TN MESONET CORRECTS PREVIOUS NON-TSTM WND GST REPORT FROM CAMP CREEK. MEASURED GUST AT THE NOAA/ATDD TOWER. EARLIER REPORTED GUST WAS ERRONEOUS. AFTER QUALITY CONTROL OF THE RAW DATA 81 MPH WAS CONFIRMED TO BE THE CORRECT WIND SPEED. 0659 AM NON-TSTM WND GST 4 SE CEDAR CREEK 35.98N 82.84W 02/20/2019 M51 MPH GREENE TN MESONET MESONET STATION PGVT1, NOLICHUCKY (4 SE CEDAR CREEK). 0327 AM NON-TSTM WND GST 1 SE SIGNAL MOUNTAIN 35.12N 85.33W 02/20/2019 M49 MPH HAMILTON TN MESONET MESONET STATION C9567, SIGNAL MOUNTAIN. 1000 AM NON-TSTM WND GST 4 WSW ROAN MOUNTAIN 36.17N 82.15W 02/20/2019 M47 MPH CARTER TN MESONET MESONET STATION D5724, 4 WSW ROAN MOUNTAIN. 0106 AM NON-TSTM WND GST 5 SE POWELLS CROSSROADS 35.13N 85.43W 02/20/2019 M43 MPH MARION TN MESONET MESONET STATION PCFT1, PRENTICE COOPER SF. 0905 AM NON-TSTM WND GST 1 WNW UNICOI 36.20N 82.37W 02/20/2019 M43 MPH UNICOI TN MESONET MESONET STATION UNIT1, WATAUGA (1 WNW UNICOI).

Just hit ~110 again. I believe it may be legit. If so, that's incredible.

For those playing along at home, 1 m/s = 2.237 mph. Alternatively, use this handy calculator. Ignoring the high outliers, it looks like Camp Creek is consistently flirting with 40 m/s - nearly 90 mph. (FYI - if that 54 m/s observation is verified, that's ~121 mph.) @Math/Met Thoughts?

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