Ellinwood Posted October 19, 2011 Share Posted October 19, 2011 So this happened: ...CAROLINAS/MID-ATLANTIC STATES/DELMARVA/PA... THE BRUNT OF A BROAD/DEEP LONGWAVE TROUGH WILL GENERALLY SHIFT EAST-NORTHEASTWARD FROM THE LOWER/MIDDLE MS RIVER VALLEY TOWARD THE OH VALLEY/APPALACHIANS THROUGH TONIGHT. INITIALLY TODAY...SEVERE POTENTIAL WILL BE FOCUSED ACROSS AREAS SUCH AS THE COASTAL CAROLINAS...WHERE STRONG/MODESTLY VEERING LOW/MID TROPOSPHERIC FLOW WILL COINCIDE WITH AN INLAND DEVELOPING MOIST/UNSTABLE NEAR-COASTAL AIRMASS. IN THIS CASE...CONCERN EXISTS INTO THE MIDDAY HOURS FOR THE POSSIBILITY OF SUPERCELLS CAPABLE OF A TORNADO OR TWO AS WELL AS DAMAGING WINDS MAINLY FOR COASTAL AREAS. INTO THE UPSTATE CAROLINAS/MID-ATLANTIC REGION AND A BIT LATER TODAY...POTENTIAL FOR STRONG/SEVERE TSTMS IS EXPECTED TO INCREASE THIS AFTERNOON/TONIGHT AS A MOIST INFLUX CONTINUES AND THE PARENT CYCLONE UNDERGOES A DEEPENING PHASE/BECOMES NEGATIVELY TILTED. WHILE A SHALLOW NEAR-SURFACE STABLE LAYER MAY TEND TO PERSIST ACROSS THE REGION AND DESTABILIZATION SHOULD OTHERWISE REMAIN MODEST...PRONOUNCED HEIGHT FALLS/DPVA AND DRAMATICALLY STRENGTHENING DEEP LAYER SOUTH-SOUTHWESTERLY FLOW PROVIDES CONCERN FOR THE DEVELOPMENT OF A LOW-TOPPED/FAST-MOVING CONVECTIVE LINE IN VICINITY OF AN EAST-NORTHEASTWARD ACCELERATING COLD FRONT FROM MID/LATE AFTERNOON THROUGH TONIGHT. EVEN WITH RELATIVELY MODEST BUOYANCY...THE DEGREE OF FORCING/VERTICAL SHEAR MAY YIELD SOME SUPERCELLS /ESPECIALLY EARLY IN THE CONVECTIVE CYCLE/ ASIDE FROM THE EVOLUTION OF A FAST-MOVING CONVECTIVE LINE WITH EMBEDDED BOWS. IN THIS SCENARIO...DAMAGING WINDS/POSSIBLE TORNADOES AND PERHAPS SOME HAIL WILL BE POSSIBLE...WITH THE RELATIVELY GREATEST POTENTIAL EXPECTED TO SPREAD/INCREASE FROM CENTRAL/NORTHERN NC INTO CENTRAL VA/MD THIS AFTERNOON/EVENING. AT LEAST A MARGINAL/ISOLATED DAMAGING WIND THREAT COULD VERY WELL CONTINUE WELL THROUGH THE NIGHT INTO PORTIONS OF PA/DELMARVA AND EVEN SOUTHERN NY. ...OH VALLEY TO THE APPALACHIANS... WITHIN THE UPPER JET EXIT REGION...LOW-TOPPED STORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON ACROSS THE REGION IN VICINITY OF THE SURFACE COLD/OCCLUDED FRONT. WHILE BOUNDARY LAYER MOISTURE/INSTABILITY WILL BE MODEST...STEEP LOW/MID LEVEL LAPSE RATES AND CONSIDERABLE VERTICAL SHEAR MAY YIELD AN AFTERNOON/EARLY EVENING RISK FOR SEVERE HAIL/WIND AND PERHAPS EVEN A BRIEF TORNADO. UNCERTAINTY REGARDING THE DEGREE OF DESTABILIZATION PRECLUDES A FURTHER EXPANSION OF THE CATEGORICAL SLIGHT RISK AT THIS TIME. Link to comment Share on other sites More sharing options...
Ian Posted October 19, 2011 Share Posted October 19, 2011 Me = winning (as usual) Link to comment Share on other sites More sharing options...
H2O Posted October 19, 2011 Share Posted October 19, 2011 Me = winning (as usual) Humble. Still a long way to go. Seeing is believing but since you didnt already meh this I will say our chances are good. Link to comment Share on other sites More sharing options...
ThreeRedheads Posted October 19, 2011 Share Posted October 19, 2011 Me = winning (as usual) It only pans out when you "meh" it! Link to comment Share on other sites More sharing options...
H2O Posted October 19, 2011 Share Posted October 19, 2011 Who knew Oct would be our best severe month this year? Link to comment Share on other sites More sharing options...
Ellinwood Posted October 19, 2011 Author Share Posted October 19, 2011 Latest SREFs from the SPC put eastern VA and NE NC in the hot zone for TORs, so long as stuff can form with the drier air rushing into the mid/upper levels. NAM is decent, RUC is crap WRT instability. GFS is similar to the NAM, with slightly more moisture in the mid/upper levels. Link to comment Share on other sites More sharing options...
CoastalWx Posted October 19, 2011 Share Posted October 19, 2011 Why is there a thread for severe wx hundreds of miles away?? Edit: well it's not just a DC subforum. Link to comment Share on other sites More sharing options...
CoastalWx Posted October 19, 2011 Share Posted October 19, 2011 Actually, that feature we talked about yesterday along the s/w might have a few good cells with it. Link to comment Share on other sites More sharing options...
mappy Posted October 19, 2011 Share Posted October 19, 2011 Good call, Ian. Now let's see if it actually pans out. Link to comment Share on other sites More sharing options...
Kmlwx Posted October 19, 2011 Share Posted October 19, 2011 Well that was a surprising outlook to wake up to. Especially given the previous day 2 outlook from yesterday....... Link to comment Share on other sites More sharing options...
CoastalWx Posted October 19, 2011 Share Posted October 19, 2011 Here is that line on the leading edge of the coldfront and upper level support. You can see the area of high RH in nrn VA. Maybe one of those fast moving lines with embedded stronger cells within it? I've found those types of lines can sometimes perform well, if you have the instability. I guess time will tell on that. SPC WRF wasn't too enthused fwiw. Link to comment Share on other sites More sharing options...
TalcottWx Posted October 19, 2011 Share Posted October 19, 2011 I had a lot of questions regarding timing but I must say at this point in time its setting up rather nicely for some good storms. Clearing coming in from the south should bring no problems with innstability and there is an impressive amount of shear over the area with good height falls and rates. Don't see what will hold this one back. Link to comment Share on other sites More sharing options...
mappy Posted October 19, 2011 Share Posted October 19, 2011 I had a lot of questions regarding timing but I must say at this point in time its setting up rather nicely for some good storms. Clearing coming in from the south should bring no problems with innstability and there is an impressive amount of shear over the area with good height falls and rates. Don't see what will hold this one back. Mid-Atlantic fail bubble Link to comment Share on other sites More sharing options...
Ian Posted October 19, 2011 Share Posted October 19, 2011 Well that was a surprising outlook to wake up to. Especially given the previous day 2 outlook from yesterday....... The 500mb pattern was screaming this. It'll probably not produce as well as the outlook makes it seem, but it shouldnt be that surprising. Link to comment Share on other sites More sharing options...
Ian Posted October 19, 2011 Share Posted October 19, 2011 the only thing left in my morning is to troll DT about his coastal low Link to comment Share on other sites More sharing options...
ThePhotoGuy Posted October 19, 2011 Share Posted October 19, 2011 I had a lot of questions regarding timing but I must say at this point in time its setting up rather nicely for some good storms. Clearing coming in from the south should bring no problems with innstability and there is an impressive amount of shear over the area with good height falls and rates. Don't see what will hold this one back. If something can go wrong, it will here. Link to comment Share on other sites More sharing options...
CoastalWx Posted October 19, 2011 Share Posted October 19, 2011 the only thing left in my morning is to troll DT about his coastal low Was he claiming this would phase into a monster nor'easter?? There is a weak surface low embedded in an overall low ambient pressure pattern....but too bad we could get the upper level support closer to this low. Link to comment Share on other sites More sharing options...
Ian Posted October 19, 2011 Share Posted October 19, 2011 Was he claiming this would phase into a monster nor'easter?? There is a weak surface low embedded in an overall low ambient pressure pattern....but too bad we could get the upper level support closer to this low. Yeah.. he backed off a minor bit recently but was still calling for a nor'easter and making fun of those who didnt through the day before yesterday. Then yesterday he was talking about a 2nd major coastal low next week and telling his "fans" on FB that there was no storm risk today. Sometimes it's shocking to me that a number of mets don't actually look at the pattern but just regurgitate model output. When there is a giant closed neg tilt progressive trough cutting to our west it's worth considering a tornado risk even if it does not happen based on our history of tornadoes down here.Not to mention the NW trend and La Nina (or sans La Nina) Link to comment Share on other sites More sharing options...
TalcottWx Posted October 19, 2011 Share Posted October 19, 2011 If something can go wrong, it will here. Seems like every region says this... lol Link to comment Share on other sites More sharing options...
Ellinwood Posted October 19, 2011 Author Share Posted October 19, 2011 High-res models aren't favoring much development in the southeastern parts of the region... too dry. Cold front will be the thing to watch tonight, especially for the DC area. Link to comment Share on other sites More sharing options...
CoastalWx Posted October 19, 2011 Share Posted October 19, 2011 Yeah.. he backed off a minor bit recently but was still calling for a nor'easter and making fun of those who didnt through the day before yesterday. Then yesterday he was talking about a 2nd major coastal low next week and telling his "fans" on FB that there was no storm risk today. Sometimes it's shocking to me that a number of mets don't actually look at the pattern but just regurgitate model output. When there is a giant closed neg tilt progressive trough cutting to our west it's worth considering a tornado risk even if it does not happen based on our history of tornadoes down here.Not to mention the NW trend and La Nina (or sans La Nina) Given the shear at the surface, it's not ridiculous to think there could be cells rotating. When I first posted to you yesterday..I thought you guys would be wedged which you are...but we talked about that feature you described, maybe giving you guys a round late day/early evening. It still seems a little questionable to me, but good luck. Sometimes these things surprise. Hopefully you can get into a pseudo warm sector on se winds. Link to comment Share on other sites More sharing options...
Kmlwx Posted October 19, 2011 Share Posted October 19, 2011 Latest SPC - Tornado threat pulled way back in terms of the 5% area. Wind still 30%. Link to comment Share on other sites More sharing options...
Ian Posted October 19, 2011 Share Posted October 19, 2011 Given the shear at the surface, it's not ridiculous to think there could be cells rotating. When I first posted to you yesterday..I thought you guys would be wedged which you are...but we talked about that feature you described, maybe giving you guys a round late day/early evening. It still seems a little questionable to me, but good luck. Sometimes these things surprise. Hopefully you can get into a pseudo warm sector on se winds. We often don't do superb in high shear low cape setups. Certainly reason not to go all in etc. But I don't think most locals even mentioned the chance of storms today. As far back as late last week (timing was a day or so earlier) this looked like a potential outcome. Plus I think there is something to pattern memory. Link to comment Share on other sites More sharing options...
H2O Posted October 19, 2011 Share Posted October 19, 2011 Bit of sun trying to peek out Link to comment Share on other sites More sharing options...
Ellinwood Posted October 19, 2011 Author Share Posted October 19, 2011 I see a bit of MUCAPE trying to move up into the region along with that batch of showers in the central Carolinas. Surface-based instability still offshore for now as the convection along the coast blocks the feed from getting into the region. Nice to see some clearing this morning, though it looks rather cloudy to the south. I'm starting to come around a little bit... feeling optimistic about the cold front stuff moving through central VA in the early-mid evening and through the DC region mid-late evening. Chasing would be hard as the timing would mean limited daylight, but we'll see how it looks in several hours when the decision to go has to be made. Link to comment Share on other sites More sharing options...
Ian Posted October 19, 2011 Share Posted October 19, 2011 Latest SPC - Tornado threat pulled way back in terms of the 5% area. Wind still 30%. Good thing I got my gloating in early. Seriously their early outlook was surprisingly bullish on the 5%. Link to comment Share on other sites More sharing options...
Kmlwx Posted October 19, 2011 Share Posted October 19, 2011 Good thing I got my gloating in early. Seriously their early outlook was surprisingly bullish on the 5%. This seems to be a recurring thing - bullish outlook at 06z then trimmed at 13z and sometimes re-bullish at 1630z. Link to comment Share on other sites More sharing options...
yoda Posted October 19, 2011 Share Posted October 19, 2011 I see sunshine Link to comment Share on other sites More sharing options...
yoda Posted October 19, 2011 Share Posted October 19, 2011 12z KIAD sounding Link to comment Share on other sites More sharing options...
BethesdaWX Posted October 19, 2011 Share Posted October 19, 2011 weren't we supposed to be socked in with clouds this morning? Actually a very nice morning. Link to comment Share on other sites More sharing options...
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