arlwx Posted July 27, 2018 Share Posted July 27, 2018 TS watch just posted for the area. Link to comment Share on other sites More sharing options...
Amped Posted July 27, 2018 Share Posted July 27, 2018 On 7/26/2018 at 5:36 PM, Kmlwx said: The rain pattern? Or the lack of severe pattern? The rain Link to comment Share on other sites More sharing options...
Kmlwx Posted July 30, 2018 Author Share Posted July 30, 2018 Did I miss a memo/change - since when did SPC start issuing 2 Day 3 outlooks each day? Link to comment Share on other sites More sharing options...
yoda Posted July 30, 2018 Share Posted July 30, 2018 1 hour ago, Kmlwx said: Did I miss a memo/change - since when did SPC start issuing 2 Day 3 outlooks each day? I dont think they do... I think they only update the Day 3 outlook if they have confidence in doing so per the 12z model suite? I have seen it done a handful of times Link to comment Share on other sites More sharing options...
high risk Posted July 31, 2018 Share Posted July 31, 2018 3 hours ago, yoda said: I dont think they do... I think they only update the Day 3 outlook if they have confidence in doing so per the 12z model suite? I have seen it done a handful of times Yoda is spot on. The day shift has the ability to update the day 3 if they desire, and I remember seeing it at some point this year during the spring. I think that this was a good call today, and there is a reasonable chance that we'll wake up Tuesday morning in SLGT for day 2. Link to comment Share on other sites More sharing options...
yoda Posted July 31, 2018 Share Posted July 31, 2018 ML Lapse Rates are weak, but 00z NAM really hinting at chance for some isolated tornadoes from 21z WED to 03z THUR Link to comment Share on other sites More sharing options...
AmericanWxFreak Posted September 24, 2018 Share Posted September 24, 2018 d3 slight Link to comment Share on other sites More sharing options...
high risk Posted September 25, 2018 Share Posted September 25, 2018 Multiple NAM nest cycles show storms initiating well ahead of the main squall line late Wednesday afternoon on some sort of lee trough. Instability is decent, and deep layer shear is probably sufficient for some svr gusts. Given how wet the soil is, I suspect that trees could come down even if gusts are only in the 35 kt range. Link to comment Share on other sites More sharing options...
yoda Posted September 25, 2018 Share Posted September 25, 2018 40 minutes ago, high risk said: Multiple NAM nest cycles show storms initiating well ahead of the main squall line late Wednesday afternoon on some sort of lee trough. Instability is decent, and deep layer shear is probably sufficient for some svr gusts. Given how wet the soil is, I suspect that trees could come down even if gusts are only in the 35 kt range. I posted this in the September disco thread: "00z 3km NAM has some interesting storms around the region from 21z WED to 00z THUR... maybe severe" Link to comment Share on other sites More sharing options...
high risk Posted September 25, 2018 Share Posted September 25, 2018 9 hours ago, yoda said: I posted this in the September disco thread: "00z 3km NAM has some interesting storms around the region from 21z WED to 00z THUR... maybe severe" That sums it up. Looking more closely, the last 5 (at least) NAM nest cycles show this, along with the 12z HRRR and all last night's Hi-Res Windows. It's rather impressive agreement. I'm still concerned about trees toppling easily in the saturated ground. Link to comment Share on other sites More sharing options...
Kmlwx Posted September 26, 2018 Author Share Posted September 26, 2018 HRRR and 3km NAM both have good storms especially in Maryland later today. Would think that as usual, the timing will be a bit earlier than the models suggest. Link to comment Share on other sites More sharing options...
high risk Posted October 31, 2018 Share Posted October 31, 2018 marginal risk for areas just south of DC Friday. With the front now likely to be much slower to move through the area, there is the opportunity for low to mid 60s dew points to return. Shear will be strong - it's just a matter of how much instability can develop. It's very possible that much of the area ends up in MRGL (with a non-zero chance of SLGT) on Friday. Link to comment Share on other sites More sharing options...
yoda Posted November 2, 2018 Share Posted November 2, 2018 Slight chance of a severe storm this evening? Damaging wind gust or very weak/brief tornado possible with MRGL risk from SPC today Also... maybe a lil something next Tuesday as well? Link to comment Share on other sites More sharing options...
yoda Posted November 2, 2018 Share Posted November 2, 2018 Maybe? From the 1630 SPC Day 1 OTLK: ...Piedmont this afternoon/evening... A lead shortwave trough over MS/AL this morning will eject quickly northeastward over the Appalachians, in advance of an amplifying midlevel trough (now over the MS Valley) that will reach the Mid Atlantic by tonight. Associated surface cyclogenesis is expected from the Piedmont this afternoon to southern New England overnight. A moist low-level air mass is present east of the Appalachians (boundary-layer dewpoints in the 60s), though widespread clouds and poor midlevel lapse rates will limit potential destabilization. Low-level mass response to the cyclogenesis will result in increasing low-level flow/shear by this evening near and just east of the path of the surface wave, across NC/VA/MD later this afternoon/evening. There will be some conditional tornado/damaging wind threat, though the depth/intensity of the convection is in question given the weak buoyancy/poor lapse rates. Will opt to maintain Marginal categorical risk for tornado/damaging winds, but will continue to monitor closely for later evidence of a small corridor of somewhat greater severe threat this afternoon along the path of the surface cyclone. Link to comment Share on other sites More sharing options...
Kmlwx Posted November 2, 2018 Author Share Posted November 2, 2018 HRRR is showing some pretty intense updraft helicity ETA: less impressive on latest run Link to comment Share on other sites More sharing options...
yoda Posted November 2, 2018 Share Posted November 2, 2018 3 minutes ago, Kmlwx said: HRRR is showing some pretty intense updraft helicity ETA: less impressive on latest run Still pretty nasty line coming through between 00z and 02z on the 16z run Link to comment Share on other sites More sharing options...
MN Transplant Posted November 2, 2018 Share Posted November 2, 2018 1 hour ago, yoda said: Still pretty nasty line coming through between 00z and 02z on the 16z run We can get rid of all of the leaves at once! Link to comment Share on other sites More sharing options...
high risk Posted November 2, 2018 Share Posted November 2, 2018 The sfc low is a going to take an extremely favorable track for the I-95 corridor. Wind profiles this evening will become as good as we can get around here, but the degree of instability is the big question. Link to comment Share on other sites More sharing options...
Kmlwx Posted November 2, 2018 Author Share Posted November 2, 2018 @high risk - how much CAPE do you think will be enough to do it? Link to comment Share on other sites More sharing options...
high risk Posted November 2, 2018 Share Posted November 2, 2018 39 minutes ago, Kmlwx said: @high risk - how much CAPE do you think will be enough to do it? great question. The issue may not be the amount of total cape, but the distribution of it. I think in these low instability/high shear events, you can work with 500 or so, but there needs to be some instability just above the sfc. Tall, skinny cape usually doesn't get it done. That forecast sounding has lousy low-level lapse rates and likely would not get the job done, assuming it's correct. History says that these low instability/high shear events rarely work out here, but there are exceptions. Link to comment Share on other sites More sharing options...
yoda Posted November 2, 2018 Share Posted November 2, 2018 8 minutes ago, high risk said: great question. The issue may not be the amount of total cape, but the distribution of it. I think in these low instability/high shear events, you can work with 500 or so, but there needs to be some instability just above the sfc. Tall, skinny cape usually doesn't get it done. That forecast sounding has lousy low-level lapse rates and likely would not get the job done, assuming it's correct. History says that these low instability/high shear events rarely work out here, but there are exceptions. Looks like SPC agrees with your thinking in their 2000 OTLK: ...Mid Atlantic... Some low possibility exists for a more focused corridor of locally damaging winds from central Virginia to the Delmarva this evening, right near the track of a surface cyclone lifting northeast. Despite cloud cover significantly limiting heating, surface dew points in the mid/upper 60s F are forecast to move north ahead of the low this evening, yielding slightly greater buoyancy. Relatively shallow convection across the Carolinas (on the nose of stronger forcing for ascent) may intensify somewhat as it meets this environment over parts of Virginia this evening. Given plentiful storm-relative helicity, any organized convection should have an attendant threat of locally damaging winds and a brief tornado or two. An upgrade to Slight Risk was considered, but concerns regarding adequate surface-based buoyancy and convective organization appear too large to warrant increased severe probabilities at this time. Link to comment Share on other sites More sharing options...
high risk Posted November 2, 2018 Share Posted November 2, 2018 MD issued by SPC. Watch possible as the strengthening line to the west approaches. Link to comment Share on other sites More sharing options...
yoda Posted November 3, 2018 Share Posted November 3, 2018 13 minutes ago, high risk said: MD issued by SPC. Watch possible as the strengthening line to the west approaches. Mesoscale Discussion 1618 NWS Storm Prediction Center Norman OK 0555 PM CDT Fri Nov 02 2018 Areas affected...Middle Atlantic Concerning...Severe potential...Watch possible Valid 022255Z - 030030Z Probability of Watch Issuance...40 percent SUMMARY...Strong convection may develop across the Middle Atlantic this evening. Damaging winds and perhaps an isolated tornado are possible. DISCUSSION...Strong mid-level height falls are spreading across the Middle Atlantic ahead of pronounced short-wave through. Slow air mass modification continues across the Delmarva where lower 60s surface dew points are now observed. Over the last hour or so, frontal convection has gradually intensified ahead of a surface low over south-central VA. Even so, this activity has yet to generate lightning which is indicative of the relatively low-topped convection. Forecast soundings ahead of this activity appear favorable for an organized squall line along the front, and perhaps even an isolated supercell. Latest CAMs suggest a gradual upward evolving line of convection along the front as it progresses into the Delmarva later this evening. There is increasing concern this activity could begin to generate locally strong winds, especially if bow-type structures evolve. Will continue to monitor this region for possible ww. ..Darrow/Hart.. 11/02/2018 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PHI...AKQ...LWX...RAH...RNK... Link to comment Share on other sites More sharing options...
yoda Posted November 3, 2018 Share Posted November 3, 2018 Borrowed from the November disco thread -- ORH mentions a TDS sig was seen in the twitter exchange with HM Link to comment Share on other sites More sharing options...
TalcottWx Posted November 3, 2018 Share Posted November 3, 2018 Embarrassing by lwx, ten minutes of TDS and no warning? Link to comment Share on other sites More sharing options...
NorthArlington101 Posted November 3, 2018 Share Posted November 3, 2018 Rotation south of Catonsville, MD where the line is wrapping up a bit. mostly gone now Link to comment Share on other sites More sharing options...
SmokeEater Posted November 3, 2018 Share Posted November 3, 2018 71 mph gust reported by a spotter in NE Carroll County. It wasn't warned? Sent from my SM-G950U using Tapatalk Link to comment Share on other sites More sharing options...
yoda Posted November 3, 2018 Share Posted November 3, 2018 1 minute ago, SmokeEater said: 71 mph gust reported by a spotter in NE Carroll County. It wasn't warned? Sent from my SM-G950U using Tapatalk It was... LWX issued a STW at 8:26pm until 9:15pm and it included Carroll County Link to comment Share on other sites More sharing options...
SmokeEater Posted November 3, 2018 Share Posted November 3, 2018 It was... LWX issued a STW at 8:26pm until 9:15pm and it included Carroll CountyK thanks, was out to dinner and didn't see it. Sent from my SM-G950U using Tapatalk Link to comment Share on other sites More sharing options...
yoda Posted November 3, 2018 Share Posted November 3, 2018 Just now, SmokeEater said: K thanks, was out to dinner and didn't see it. Sent from my SM-G950U using Tapatalk That's alright Seems LWX missed an obvious TW though reading the HM/ORH tweet posted above Link to comment Share on other sites More sharing options...
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