HM Posted August 9, 2012 Share Posted August 9, 2012 yeah i was just kinda drooling at that. i think the primary risk zone is perhaps n md into c pa for now. im not confident the area highlighted by sref is not too far north, particularly if there is a secondary lee low of some sort which does seem possible. I think the big thing to take away from these latest trends is the increased LLJ and better hodos/SRH showing up. Now we actually have potential to produce a few tornadoes somewhere. The NAM even hints at the threat continuing into the overnight hours in eastern areas. I think the SPC will definitely bring the SLT a bit NW but hold it for much of the area. Link to comment Share on other sites More sharing options...
TUweathermanDD Posted August 9, 2012 Share Posted August 9, 2012 I think the big thing to take away from these latest trends is the increased LLJ and better hodos/SRH showing up. Now we actually have potential to produce a few tornadoes somewhere. The NAM even hints at the threat continuing into the overnight hours in eastern areas. I think the SPC will definitely bring the SLT a bit NW but hold it for much of the area. Probably should introduce a 30% area somewhere though tors obviously wouldnt be too high but this would account for it on a day 2. Link to comment Share on other sites More sharing options...
HM Posted August 9, 2012 Share Posted August 9, 2012 Probably should introduce a 30% area somewhere though tors obviously wouldnt be too high but this would account for it on a day 2. If the rest of the 00z data follows suit, I could see a 30% area. The exact speed and evolution of the upper low / vertical stack process will determine the NE extent of the SLT risk. Link to comment Share on other sites More sharing options...
Ian Posted August 9, 2012 Share Posted August 9, 2012 I think the big thing to take away from these latest trends is the increased LLJ and better hodos/SRH showing up. Now we actually have potential to produce a few tornadoes somewhere. The NAM even hints at the threat continuing into the overnight hours in eastern areas. I think the SPC will definitely bring the SLT a bit NW but hold it for much of the area. Yeah, that's true. The NAM/SREF is notably stronger with the ULL and sfc low now compared to early runs. Will be interesting to see if the GFS follows at all at least. This might be one of those situations where pattern recognition catches on before the models to some degree... tho it's still fragile so shouldn't get too cocky. Link to comment Share on other sites More sharing options...
Kmlwx Posted August 9, 2012 Share Posted August 9, 2012 Hawt Link to comment Share on other sites More sharing options...
wxmeddler Posted August 9, 2012 Share Posted August 9, 2012 Sill kinda meh. Worried about morning clouds and timing of the front. As a side note the NAM sends a pocket of warmer mid-level air around in the afternoon cutting off the good Mid-Level Lapse rates, which always seems to be a limiting factor around here. (ie. MD/So.PA) Link to comment Share on other sites More sharing options...
Dsnowx53 Posted August 9, 2012 Share Posted August 9, 2012 The new 00z NAM and 21z SREF are painting a pretty decent picture FRI PM for a good chunk of PA. The SIG TOR probs came up on the SREF and the NAM is now developing an appreciable LLJ (30-35kts) in PA. I wish the 850mb winds had more of a westerly component, though. I don't like seeing 925mb and 850mb winds east of due south. Link to comment Share on other sites More sharing options...
HM Posted August 9, 2012 Share Posted August 9, 2012 I wish the 850mb winds had more of a westerly component, though. I don't like seeing 925mb and 850mb winds east of due south. Well if we are going to wish, I'd wish for a ton of other things too. Most of us have been blah on this setup but the fact a 30kt LLJ is beginning to show up is at least a noteworthy trend. Also, winds do veer sufficiently just above 850mb, enough to increase the SRH and subsequent TOR probs. Let's hope the GFS is more promising... Link to comment Share on other sites More sharing options...
Ian Posted August 9, 2012 Share Posted August 9, 2012 The location of the 500 low and sfc lows are both pretty classic for a tornado day in the mid Atlantic. I wouldn't expect an outbreak per se but without analyzing every variable I'd be surprised if the models are close and there are no tornadoes anywhere. Link to comment Share on other sites More sharing options...
Dsnowx53 Posted August 9, 2012 Share Posted August 9, 2012 Well if we are going to wish, I'd wish for a ton of other things too. Most of us have been blah on this setup but the fact a 30kt LLJ is beginning to show up is at least a noteworthy trend. Also, winds do veer sufficiently just above 850mb, enough to increase the SRH and subsequent TOR probs. Let's hope the GFS is more promising... That is true. The GFS also seems to show some 25+kt 925mb winds in the Mid Atlantic region. The directional shear might not be IDEAL in the lower levels, but there is some, and the speed shear in the lower levels looks great. 500mb winds aren't terrible, either. A bit disjointed, which is annoying, but if we can get them to be above 30 knots, that might be just enough to not "kill off" our low-level shear. And the 500mb synoptic pattern is hard to ignore. It has a much better "general look" than most of the threats we've had in the past month. And they definitely do veer towards the west above 850mb; the 700mb winds are evident of that. I'm still a bit afraid though that there is TOO much moisture with winds east of due south in the lower levels and a SW flow aloft combined with a weak CAP...I hope that does not lead to just a heavy rain event that occurs before we even get a chance to fully destabilize. But our LCL heights should be low, too. Link to comment Share on other sites More sharing options...
yoda Posted August 9, 2012 Share Posted August 9, 2012 GFS soundings show a bit more promise off Earl Barker.. but shear is kinda weak.. 30kts in the 0-6km level Link to comment Share on other sites More sharing options...
Dsnowx53 Posted August 9, 2012 Share Posted August 9, 2012 GFS soundings show a bit more promise off Earl Barker.. but shear is kinda weak.. 30kts in the 0-6km level The 0-6km shear is never going to be something that's particularly impressive in this setup given the fact that the 500mb winds are SW as opposed to W or NW, so the directional shear up to that layer is pretty low. It's the low-level shear, in this setup, that will help produce, and with the increasing LLJ, we might have what we need. We'll see. Link to comment Share on other sites More sharing options...
yoda Posted August 9, 2012 Share Posted August 9, 2012 New Day 2 Link to comment Share on other sites More sharing options...
yoda Posted August 9, 2012 Share Posted August 9, 2012 ...SRN/CNTRL APPALACHIAN REGION THROUGH MID ATLANTIC AND A PORTION OF NERN STATES... STORMS WILL LIKELY BE ONGOING ALONG AND JUST AHEAD OF THE COLD FRONT WITHIN WARM CONVEYOR BELT ACROSS PORTIONS OF THE TN AND OH VALLEYS WITH GREATEST COVERAGE EXPECTED WEST OF THE APPALACHIANS. UPPER 60S TO NEAR 70 DEWPOINTS WILL RESIDE IN PRE-FRONTAL WARM SECTOR. DIABATIC WARMING OUTSIDE OF CLOUDY AREAS WILL DESTABILIZE THE BOUNDARY LAYER...BUT WEAK MID LEVEL LAPSE RATES SHOULD TEMPER INSTABILITY SOMEWHAT WITH MLCAPE GENERALLY AOB 1500 J/KG. STORMS SHOULD INCREASE IN COVERAGE AND INTENSITY AHEAD OF THE COLD FRONT DURING THE DAY...LIKELY EVOLVING INTO LINES AND CLUSTERS...THOUGH A FEW DISCRETE CELLS WILL ALSO POSSIBLE. VERTICAL SHEAR IN MOST OF WARM SECTOR WILL NOT BE PARTICULARLY STRONG OWING TO THE EQUIVALENT BAROTROPIC NATURE OF THE UPPER LOW. EXPECTED MARGINAL THERMODYNAMIC ENVIRONMENT AND MODEST VERTICAL SHEAR COULD SERVE AS POSSIBLE LIMITING FACTORS FOR A MORE ROBUST SEVERE THREAT. SOMEWHAT STRONGER DEEP AND LOW LEVEL SHEAR MAY DEVELOP FROM NRN MID ATLANTIC INTO ERN PORTION OF THE OH VALLEY AND NERN STATES IN ASSOCIATION WITH A MID LEVEL JET ROTATING THROUGH SERN PERIPHERY OF THE UPPER LOW. IF SUFFICIENT INSTABILITY DEVELOPS...STORMS MAY BECOME A BIT MORE ORGANIZED IN THIS REGION WITH POTENTIAL FOR EMBEDDED MESOCYCLONES AND BOWING SEGMENTS. DAMAGING WIND WILL BE THE MAIN THREAT...BUT A CONDITIONAL THREAT WILL EXIST FOR A COUPLE OF TORNADOES. Link to comment Share on other sites More sharing options...
andyhb Posted August 9, 2012 Share Posted August 9, 2012 D2 mentioning tornadoes, sounds like we could get a few surprises with potentially discrete cells in the stronger LL shear regime. Link to comment Share on other sites More sharing options...
mattie g Posted August 9, 2012 Share Posted August 9, 2012 I just want it to rain. Link to comment Share on other sites More sharing options...
Ji Posted August 9, 2012 Share Posted August 9, 2012 I just want it to rain. I'm so tired of the sun. I hate the sun Link to comment Share on other sites More sharing options...
mattie g Posted August 9, 2012 Share Posted August 9, 2012 There was a nice low cloud deck hanging over the river at the Wilson Bridge and a few miles across the bridge in Maryland at around 6:45 this morning. It's pretty cool to get onto the Beltway at the Mixing Bowl on mornings like these and look off to the east to see the low clouds lingering over the river in the distance. Quietion: Why is it that these low clouds and fog so often stretch well into Maryland, but not on the Virginia side of the river? I would have thought the clouds would stick around over and right next to the river, but it just seems to me that they're often also well east of the river. Just an observation that got me curious... Link to comment Share on other sites More sharing options...
mattie g Posted August 9, 2012 Share Posted August 9, 2012 I'm so tired of the sun. I hate the sun Link to comment Share on other sites More sharing options...
Kmlwx Posted August 9, 2012 Share Posted August 9, 2012 06z NAM-hires for 03z Saturday omg omg derecho?! lol Link to comment Share on other sites More sharing options...
snowfan Posted August 9, 2012 Share Posted August 9, 2012 06z NAM-hires for 03z Saturday omg omg derecho?! lol Close the bridge! Close the bridge! Link to comment Share on other sites More sharing options...
Kmlwx Posted August 9, 2012 Share Posted August 9, 2012 Close the bridge! Close the bridge! It looks like a boomerang of death. Link to comment Share on other sites More sharing options...
mattie g Posted August 9, 2012 Share Posted August 9, 2012 I <3 derechoes. Link to comment Share on other sites More sharing options...
HM Posted August 9, 2012 Share Posted August 9, 2012 I <3 derechoes. First step is having the right synoptic pattern (e.g. a closed mid level anticyclone with extremely hot temperatures and high dewpoints beneath an EML). Link to comment Share on other sites More sharing options...
mappy Posted August 9, 2012 Share Posted August 9, 2012 It looks like a boomerang of death. McKayla is not impressed Link to comment Share on other sites More sharing options...
Kmlwx Posted August 9, 2012 Share Posted August 9, 2012 McKayla is not impressed lol Link to comment Share on other sites More sharing options...
WoodbineWX Posted August 9, 2012 Share Posted August 9, 2012 Tell everyone that it will be a derecho to end all derecho events. Essentially Dec 2012 coming early. Say your farewells and wish everyone the best. Then, while all of the CWG lay people followers are horrified and stocking up - we can have a DC gtg and laugh at all the idiots. LOL Link to comment Share on other sites More sharing options...
Ian Posted August 9, 2012 Share Posted August 9, 2012 Look like my first MA chase. God help me. Link to comment Share on other sites More sharing options...
mattie g Posted August 9, 2012 Share Posted August 9, 2012 First step is having the right synoptic pattern (e.g. a closed mid level anticyclone with extremely hot temperatures and high dewpoints beneath an EML). Oh noes! No derechoes? Link to comment Share on other sites More sharing options...
Ellinwood Posted August 9, 2012 Author Share Posted August 9, 2012 Look like my first MA chase. God help me. Wooooooo chasing! The ratio of luck:skill is a lot higher for tornadoes in the Mid-Atlantic compared to the Plains I need to see if I can stop by Jason's house to borrow the laptop stand. You'll get to do the nav and radar watching from the front seat! Link to comment Share on other sites More sharing options...
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