George BM Posted March 25, 2021 Share Posted March 25, 2021 58 minutes ago, vastateofmind said: Great reminder about Radarscope -- I'm going to pull the trigger on that today or tomorrow. Have been meaning to buy it for the past year or two for my phone, but always found other apps to waste money on. I actually just got Radarscope yesterday for my phone. It's wonderful for tracking severe weather. 2 Link to comment Share on other sites More sharing options...
MillvilleWx Posted March 25, 2021 Share Posted March 25, 2021 My friends in the Birmingham area live near Helena, which is a small town to the south-southwest of BMX. They avoided the tornado hitting their new home getting built by 200 ft. Just some very minor shingle damage. Absolutely lucky as heck to avoid total destruction. Their future neighbors were not so lucky with their new home getting flattened . My friends are an EM for Jefferson county (Birmingham's county), and my other friend (her husband) is a met at BMX. This is the second time he's had to go survey damage within a football field from their home in the past 14 months 1 1 Link to comment Share on other sites More sharing options...
Mrs.J Posted March 25, 2021 Share Posted March 25, 2021 That storm near Greensboro AL looks nasty. Just got a PDS on it. Link to comment Share on other sites More sharing options...
yoda Posted March 26, 2021 Share Posted March 26, 2021 FWIW, 00z NAM shows intrigue for Sunday afternoon (18z to 21z soundings).... with some showing up at DCA/EZF Link to comment Share on other sites More sharing options...
yoda Posted March 26, 2021 Share Posted March 26, 2021 And we begin 1 Link to comment Share on other sites More sharing options...
yoda Posted March 26, 2021 Share Posted March 26, 2021 oh hello there hatching.... on Day 3 Day 3 Prob. Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area SIG SEVERE 59,374 15,628,657 Charlotte, NC...Washington, DC...Virginia Beach, VA...Raleigh, NC...Norfolk, VA... Link to comment Share on other sites More sharing options...
yoda Posted March 26, 2021 Share Posted March 26, 2021 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Fri Mar 26 2021 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM A PORTION OF THE SOUTHERN APPALACHIANS INTO THE CAROLINAS AND MIDDLE ATLANTIC... ...SUMMARY... Strong to severe storms are possible from the Carolinas into the Middle Atlantic region Sunday afternoon. A few strong to severe storms will also be possible from the central and southern Appalachian region into a portion of the Tennessee Valley and Southeast States. ...Mid Atlantic into the Carolinas... An intense low-level jet will shift from the southern and central Appalachians into the Carolinas and Mid Atlantic during the day in association with a progressive northern-stream shortwave trough. A warm front will move northward through the Mid Atlantic during the day prior to the arrival of a cold front. Upper 50s to low 60s F dewpoints will advect through the warm sector contributing to modest instability as the surface layer warms with up to 1000 J/kg MLCAPE possible. Thunderstorms are expected to develop along and just ahead of the cold front as it advances into this region during the late afternoon and early evening. This activity will be embedded within strong deep layer wind profiles that will support bowing structures as well as a few supercells. Damaging wind will be the main threats, but a few tornadoes and some hail will also be possible before the front moves offshore during the evening. Link to comment Share on other sites More sharing options...
Kmlwx Posted March 26, 2021 Author Share Posted March 26, 2021 Ummmm - did not expect that Link to comment Share on other sites More sharing options...
Kmlwx Posted March 26, 2021 Author Share Posted March 26, 2021 Yeah the NAM looks pretty decent for Sunday around 18-21z. Let's see if it pans out. We are fringed by the hatching on that SPC outlook...but it's also day 3. Link to comment Share on other sites More sharing options...
CAPE Posted March 26, 2021 Share Posted March 26, 2021 From Mount Holly this morning- By Sunday afternoon the precipitation field will likely take on a more convective appearance as elevated instability develops. The primary fcst question then becomes, can we warm enough near the surface to overcome the fairly stout low-lvl inversion that is progged to be in place? If we can... and thus generate sfc- based instability there would be an appreciable severe threat as kinematics will not be lacking with 850mb winds around 60-70kts and 925mb winds up to 50kts. However, at this time, the thermal evolution is not clear, particularly given the low-lvl cloud cover and overunning precipitation earlier in the day. This uncertainty is partially quantified by the fact that the NBM`s IQR for Sunday`s MaxTs is 7-9 degrees, which represents a higher than usual spread in its components. If storms remain elevated it should be a fairly mundane spring rainfall event, with current QPF in the 0.75-1 inch range (although with convection in play locally higher totals are possible). Link to comment Share on other sites More sharing options...
Kmlwx Posted March 26, 2021 Author Share Posted March 26, 2021 Take a look at this frame from the latest SREF on the SPC maps for 18z on Sunday............wow. That's some drool worthy stuff for @yoda 1 Link to comment Share on other sites More sharing options...
Kmlwx Posted March 26, 2021 Author Share Posted March 26, 2021 The 12z NAM (12km) is kind of insane for Sunday now. It looks like it tries to pop a little low right along the Mason-Dixon line which really ramps up the potential. Supercell composite is very high for Sunday PM for a decent chunk of the area. Remove that little meso-low feature and things maybe aren't as robust. Will be interesting to see what the 3km looks like (at range of course). For March...this has some higher end potential. Link to comment Share on other sites More sharing options...
George BM Posted March 26, 2021 Share Posted March 26, 2021 The last time, from my memory anyway, that DC was in a hatched zone was on a Day 3 outlook for April 6, 2017. The last time, from my memory anyway, that DC was in a hatched zone at gametime was on February 24, 2016. Link to comment Share on other sites More sharing options...
Kmlwx Posted March 26, 2021 Author Share Posted March 26, 2021 1 minute ago, George BM said: The last time, from my memory anyway, that DC was in a hatched zone was on a Day 3 outlook for April 6, 2017. The last time, from my memory anyway, that DC was in a hatched zone at gametime was on February 24, 2016. I was kind of surprised to see the hatching for a D3 outlook. The outlook text reads less like a hatched day and more like a higher end SLGT day. Could just be because it's out in range for now. It looks like the NAM nest focuses the best parameters just to the west of the metro area, the 12k version had it in the immediate metro area and east. It looks like it still has that little meso-low type feature. 2 Link to comment Share on other sites More sharing options...
George BM Posted March 26, 2021 Share Posted March 26, 2021 1 minute ago, Kmlwx said: I was kind of surprised to see the hatching for a D3 outlook. The outlook text reads less like a hatched day and more like a higher end SLGT day. Could just be because it's out in range for now. It looks like the NAM nest focuses the best parameters just to the west of the metro area, the 12k version had it in the immediate metro area and east. It looks like it still has that little meso-low type feature. Yeah. March climo and the tendency for overnight storms to our west to sink south of modeled are really keeping my expectations in check for Sunday atm. Link to comment Share on other sites More sharing options...
high risk Posted March 26, 2021 Share Posted March 26, 2021 1 hour ago, Kmlwx said: The 12z NAM (12km) is kind of insane for Sunday now. It looks like it tries to pop a little low right along the Mason-Dixon line which really ramps up the potential. Supercell composite is very high for Sunday PM for a decent chunk of the area. Remove that little meso-low feature and things maybe aren't as robust. Will be interesting to see what the 3km looks like (at range of course). For March...this has some higher end potential. I fully agree. The shear on all guidance is incredibly impressive - I'm even seeing big, looping hodographs and PDS TOR on some forecast soundings. Still some questions about instability: the parent NAM by far looks the best. GFS keeps showers and clouds around for much of the day, limiting heating. NAM nest seems to mix out the low level moisture a bit during the afternoon, although even that model has an impressive QLCS approaching late in the day. 1 Link to comment Share on other sites More sharing options...
Kmlwx Posted March 26, 2021 Author Share Posted March 26, 2021 46 minutes ago, high risk said: I fully agree. The shear on all guidance is incredibly impressive - I'm even seeing big, looping hodographs and PDS TOR on some forecast soundings. Still some questions about instability: the parent NAM by far looks the best. GFS keeps showers and clouds around for much of the day, limiting heating. NAM nest seems to mix out the low level moisture a bit during the afternoon, although even that model has an impressive QLCS approaching late in the day. Seems the model biases are always this way. NAM always tends to show bonkers soundings/parameters and GFS is more muted. Could be the first "true" threat of the year - will it also be the first bust? Link to comment Share on other sites More sharing options...
Kmlwx Posted March 26, 2021 Author Share Posted March 26, 2021 LWX mentions next Wednesday as another potential strong thunderstorm threat - but says it could be more of a high shear/low CAPE kind of setup due to timing and limited warm air advection. Link to comment Share on other sites More sharing options...
Kmlwx Posted March 26, 2021 Author Share Posted March 26, 2021 18z NAM continues to look decent for Sunday. It does look slightly less robust in a few regards - but really it's noise. Seems the potential is still solidly on the table. Link to comment Share on other sites More sharing options...
CAPE Posted March 26, 2021 Share Posted March 26, 2021 This sounds ominous. I will prepare to take shelter. From Mount Holly AFD- As the system`s cold front approaches from the west into the late afternoon and evening, MLCAPE values should be on the order of 500 to 1000 J/kg (possibly even higher across Delmarva and southern NJ) across much of the inland portions of the area. Meanwhile, deep layer shear will be quite strong (50-60+ kts) across the warm sector and low-level shear will also be very strong. Forecast effective SRH values will be on the order of 300-400 m2/s2 with large curved hodographs, so the kinematic profile will support organized storms and rotating updrafts of any deep convection that develops in the warm sector or along the cold front. It`s still a little too far out to determine the convective evolution, but this severe event needs to be monitored very closely. SPC has highlighted southern portions of the forecast area with a threat of significant severe weather, and damaging winds, large hail, and tornadoes are all possible Sunday afternoon and evening. 2 Link to comment Share on other sites More sharing options...
andyhb Posted March 27, 2021 Share Posted March 27, 2021 What in the crap are these soundings I'm pulling on Sunday off the NAM/NAM 3 km... 3000 J/kg CAPE in the Mid Atlantic in March (not to mention with a shear profile favorable for sig severe)? 6 Link to comment Share on other sites More sharing options...
Kmlwx Posted March 27, 2021 Author Share Posted March 27, 2021 8 minutes ago, andyhb said: What in the crap are these soundings I'm pulling on Sunday off the NAM/NAM 3 km... 3000 J/kg CAPE in the Mid Atlantic in March (not to mention with a shear profile favorable for sig severe)? People start paying attention when you pop in. 2 Link to comment Share on other sites More sharing options...
NorthArlington101 Posted March 27, 2021 Share Posted March 27, 2021 16 minutes ago, andyhb said: What in the crap are these soundings I'm pulling on Sunday off the NAM/NAM 3 km... 3000 J/kg CAPE in the Mid Atlantic in March (not to mention with a shear profile favorable for sig severe)? 6 minutes ago, Kmlwx said: People start paying attention when you pop in. For real, now I'm interested. Ellinwood was honking on Twitter a little bit earlier too. I'd love to do some casual storm chasing in my neck of the woods. I've seen some local guys chase and get great photos around here. 1 Link to comment Share on other sites More sharing options...
Eskimo Joe Posted March 27, 2021 Share Posted March 27, 2021 Interested to see if this becomes a bias nationwide or just in Dixie Alley 1 Link to comment Share on other sites More sharing options...
Kmlwx Posted March 27, 2021 Author Share Posted March 27, 2021 Latest guidance seems to want to get the best activity to the south and east of the DC area. Not surprising - and certainly inline with the overall SPC outlook area. NAM and the nest don't look quite as impressive as they did for the immediate metro area as they did yesterday. 1 Link to comment Share on other sites More sharing options...
CAPE Posted March 27, 2021 Share Posted March 27, 2021 Enhanced risk for SE VA now. Link to comment Share on other sites More sharing options...
Kmlwx Posted March 27, 2021 Author Share Posted March 27, 2021 The GFS has pretty paltry CAPE values for most of the metro area. The NAM looks pretty meh as well - but the NAM nest does send a healthy line through. If it were me at the SPC desk (thank god it isn't) I'd probably trim the hatched area to remove DC proper. Severe weenies near Fredericksburg are seemingly better positioned. Link to comment Share on other sites More sharing options...
csnavywx Posted March 27, 2021 Share Posted March 27, 2021 Decent agreement on some sunrise surprise tomorrow morning. MUCAPE of ~1000-1500 and plenty of shear for morning TS. The big question I have is the evolution of overnight convection further west. If that decays slowly, then we may be left with a bunch of convective debris in the warm sector, and it's going to be tough for severe further north. 3 Link to comment Share on other sites More sharing options...
Kmlwx Posted March 27, 2021 Author Share Posted March 27, 2021 9 hours ago, Eskimo Joe said: Interested to see if this becomes a bias nationwide or just in Dixie Alley If this bias applies tomorrow - the entire subforum would be out of the game Link to comment Share on other sites More sharing options...
yoda Posted March 28, 2021 Share Posted March 28, 2021 9 hours ago, Kmlwx said: The GFS has pretty paltry CAPE values for most of the metro area. The NAM looks pretty meh as well - but the NAM nest does send a healthy line through. If it were me at the SPC desk (thank god it isn't) I'd probably trim the hatched area to remove DC proper. Severe weenies near Fredericksburg are seemingly better positioned. Hatched wind remains for our area in new Day 1 morning update... along with 5% tor Link to comment Share on other sites More sharing options...
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