Dark Energy Posted August 20, 2011 Share Posted August 20, 2011 We're in a slight risk on the day 2 outlook. The 0-6 km shear is 30+kts so that will due. Much better than what we saw recently as upper trof dives in from the NW. There is even some low level helicity showing up that may add to any spinups possible along the convective line that forms late. SPC mentions supercells as a main mode, and that is in agreement....which may form into a line late. ML/MU CAPE is on the order of 1500 - 2500 J./kg. Surely ideal for good storms. The only issue is ML lapse rates...they are marginal but may due the trick. Not ideal. Mid level temps are higher than yesterday, so big hail may be hard to come by. SREF mean has a good risk of svr storms FWIW, mainly over NJ, but the entire area could see a hit ahead of a good front. At this point, I wound venture a 60% chance we see SCT severe storms across the region. We;ll see how the models are tomorrow. Thoughts welcome. Link to comment Share on other sites More sharing options...
Dark Energy Posted August 20, 2011 Author Share Posted August 20, 2011 BTW, did anyone notice that the Ewall expanded their maps? They now include S FL so the entire E coast is included. FINALLY. I bet that pissed off the FL people to no end since they were not included before. LOL Link to comment Share on other sites More sharing options...
tmagan Posted August 20, 2011 Share Posted August 20, 2011 I was going to post that there probably should be a 30% region delineated on the SPC Day2 probability maps. Link to comment Share on other sites More sharing options...
earthlight Posted August 20, 2011 Share Posted August 20, 2011 I was going to post that there probably should be a 30% region delineated on the SPC Day2 probability maps. I agree. The only reason I would hesitate is because the models are still shifting in a sense. A few runs ago, the NAM had a ~998mb low invof western new england. That said, as depicted right now, this looks like a 30% set up to me. The height falls are impressive, the forcing is good, and the thermodynamics are there too. The shear has improved the past few model cycles as well. By later today we can get into more intricate details & number crunching, but for now the synoptic set up is a good one. Link to comment Share on other sites More sharing options...
earthlight Posted August 20, 2011 Share Posted August 20, 2011 SREF gon wild for tomorrow's event....it's latest run: Link to comment Share on other sites More sharing options...
earthlight Posted August 20, 2011 Share Posted August 20, 2011 The SREF also has 150 m2/s2 of 0-1km helicity over SE NY into Western New England..where I think there could be a locally better tornado threat. Link to comment Share on other sites More sharing options...
earthlight Posted August 20, 2011 Share Posted August 20, 2011 OKX PROBABILITY FOR A SIGNIFICANT SEVERE WEATHER EVENT INCREASING. STRONG JET DROPPING OUT OF THE CANADIAN ROCKIES WILL APPROACH SUN AFTN. 00Z NAM/GFS PROG A 110+ KT JET MAX. THIS WILL RESULT IN A DEEPENING H5 TROF PASSING THRU THE CWA. UNSTABLE AIRMASS ACROSS THE CNTRL CONUS WILL COMBINE WITH ATLANTIC MOISTURE TO PRIME THE ATMOSPHERE AHEAD OF THE UPR SYSTEM AND ASSOCIATED COLD FRONT. CAP BREAKS AROUND 15Z...SO THERE MAY BE A FEW ISOLD TSTMS ACROSS WRN ZONES EARLY IN THE DAY. OTHERWISE...FRONT AND UPR FORCING ARRIVE LATER IN THE AFTN AND EVE. THIS IS WHEN THE THREAT APPEARS HIGHEST ACROSS THE MAJORITY OF THE CWA ATTM. SUPERCELLS POSSIBLE...ESPECIALLY IN THE AFTN AND EVE...WITH A FAVORABLE SHEAR/CAPE BALANCE PER THE BRN. A SECONDARY FLARE UP OVERNIGHT AS THE RR QUAD OF THE JET PROVIDES DIVERGENCE ALOFT. THIS MAY EVOLVE INTO A STRONG SQUALL LINE. ALL THREATS WITH REGARD TO SEVERE WEATHER APPEAR TO BE IN PLAY WITH THIS EVENT. SEVERE WORDING HAS BEEN ADDED TO THE FCST AND GRIDS SUN AFTN THRU ALL OF SUN NIGHT AND WILL BE MAINTAINED IN THE HWO. Link to comment Share on other sites More sharing options...
LocoAko Posted August 20, 2011 Share Posted August 20, 2011 Examining the EWR BUFKIT for tomorrow, the 12Z NAM has some pretty significant elements to it. CAPE increases to ~1800 J/kg tomorrow night at around 00Z, and 0-3 km helicity values also soar to +350 m2/s2 just before 00Z as well. (Precipitable Water values also exceed 2 in around this time... not what the ground needs right now). Equilibrium level heights are above 40,000 ft and LCL heights are 4,000 ft and plummet to 1,000 ft at 00Z. By 17 Z, low level lapse rates are superadiabatic up to 900 mb. Check out this hodograph for 23Z tomorrow: 43 m/s of shear and a helicity of over 450 m2/s2. Not too shabby. Did notice the NCAPE never gets above 0.2 and is pretty low but you can't win 'em all I guess. Link to comment Share on other sites More sharing options...
Stormlover74 Posted August 20, 2011 Share Posted August 20, 2011 Nearly every time we have a perfect or near perfect setup we get screwed. Meanwhile the past 2 days with marginally good setups were both great... Link to comment Share on other sites More sharing options...
earthlight Posted August 20, 2011 Share Posted August 20, 2011 Nearly every time we have a perfect or near perfect setup we get screwed. Meanwhile the past 2 days with marginally good setups were both great... This phrase is starting to get over used.. Link to comment Share on other sites More sharing options...
LocoAko Posted August 20, 2011 Share Posted August 20, 2011 This phrase is starting to get over used.. ...and clearly doesn't make any sort of logical sense and deals solely with a poster's personal expectations. Don't get carried away by good storm potential and everything won't seem to suck all the time... Link to comment Share on other sites More sharing options...
Stormlover74 Posted August 20, 2011 Share Posted August 20, 2011 I guess its more about people dismissing threats (not necessarily on this board) due to one or more missing factors. Everything can look perfect but its not a guarantee anything will happen and vice versa. ...and clearly doesn't make any sort of logical sense and deals solely with a poster's personal expectations. Don't get carried away by good storm potential and everything won't seem to suck all the time... Link to comment Share on other sites More sharing options...
earthlight Posted August 20, 2011 Share Posted August 20, 2011 ...and clearly doesn't make any sort of logical sense and deals solely with a poster's personal expectations. Don't get carried away by good storm potential and everything won't seem to suck all the time... That too. Anyway, drawing on your post, the 09z SREF has more impressive 0-1km and 0-3km helicity values when compared to it's previous runs. As a result it has a small area of favorable "significant tornado ingredients" over Northern NJ/Northeast PA and Southeast NY. We will have to see if these numbers come to fruition as modeled. If they do..given the wind fields and effective shear in place (sref now has 40+kts of effective bulk shear), we could be looking at an impressive squall line or groups of bowing segments..with a localized supercell/tornado threat near the better low level shear. Link to comment Share on other sites More sharing options...
blizzardof09 Posted August 20, 2011 Share Posted August 20, 2011 One thing is probably for sure though, when they get to suffolk county on long island they'll most likey be nothing but showers and crack of thunder or two. Sorry for the debby downer of a post it has seemed to be a reoccuring theme with me this year, where the city and nassua county get hit good and I get just showers with some thunder. Earthlight your right though that the srefs look insane but I'm just not counting on much where I am. You on the other hand will probably post mt.earthlight erupting again for the second time in three days lol Link to comment Share on other sites More sharing options...
earthlight Posted August 20, 2011 Share Posted August 20, 2011 One thing is probably for sure though, when they get to suffolk county on long island they'll most likey be nothing but showers and crack of thunder or two. Sorry for the debby downer of a post it has seemed to be a reoccuring theme with me this year, where the city and nassua county get hit good and I get just showers with some thunder. Earthlight your right though that the srefs look insane but I'm just not counting on much where I am. You on the other hand will probably post mt.earthlight erupting again for the second time in three days lol It comes with the territory, man. Long Island sticks out into the Atlantic ocean. Also, ahead of a good amount of severe weather events...even the ones that get to NYC...the low level winds turn southeast along the coast. This pretty much puts the squabash on the threat over Eastern Long Island. Link to comment Share on other sites More sharing options...
earthlight Posted August 20, 2011 Share Posted August 20, 2011 ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE WRN NEW ENGLAND...ERN NY AND THE MID-ATLANTIC... ...NEW ENGLAND/ERN NY/MID-ATLANTIC/CNTRL APPALACHIANS... A LARGE UPPER-LEVEL TROUGH WILL MOVE EWD ACROSS THE GREAT LAKES AND OH VALLEY SUNDAY AS A 60 TO 75 KT MID-LEVEL JET ROUNDS THE BASE OF THE TROUGH. AHEAD OF THE UPPER-LEVEL TROUGH....MODEL FORECASTS INITIATE NUMEROUS THUNDERSTORMS ALONG AN AXIS OF MODERATE INSTABILITY FROM WRN NEW ENGLAND SSWWD INTO THE MID-ATLANTIC BY EARLY SUNDAY AFTERNOON. FORECAST SOUNDINGS ALONG THIS CORRIDOR AT 21Z SHOW MLCAPE VALUES IN THE 1200 TO 2000 J/KG RANGE WITH MODERATE DEEP LAYER SHEAR AND SOME DIRECTIONAL SHEAR IN THE LOW-LEVELS. AS THE NOSE OF THE MID-LEVEL JET MOVES INTO THE NERN STATES SUNDAY AFTERNOON...DEEP LAYER SHEAR WILL INCREASE MAKING CONDITIONS FAVORABLE FOR SEVERE STORMS ALONG THE INSTABILITY AXIS. IN ADDITION...MODEL FORECASTS INTENSIFY A LOW-LEVEL JET ACROSS THE SLIGHT RISK AREA IN THE LATE AFTERNOON SUGGESTING WIND DAMAGE COULD BE THE GREATEST THREAT. CONSIDERING 500 MB TEMPS SHOULD BE IN THE -10 C TO -12 C RANGE...HAIL WILL ALSO BE POSSIBLE IN AREAS WHERE INSTABILITY AND SHEAR ARE MAXIMIZED. ALTHOUGH MORE CONDITIONAL...AN ISOLATED TORNADO THREAT COULD ALSO DEVELOP NEAR THE CENTER OF THE LOW-LEVEL JET IN THE MID-ATLANTIC WHERE THE STRONGEST INSTABILITY IS FORECAST AND SFC DEWPOINTS SHOULD BE IN THE MID TO UPPER 60S F. Link to comment Share on other sites More sharing options...
SBUWX23 Posted August 20, 2011 Share Posted August 20, 2011 It comes with the territory, man. Long Island sticks out into the Atlantic ocean. Also, ahead of a good amount of severe weather events...even the ones that get to NYC...the low level winds turn southeast along the coast. This pretty much puts the squabash on the threat over Eastern Long Island. There have been many events this summer that have made it out to eastern LI. Most of them from my memory though have moved in from the north rather than the west. Aug 1 sticks out for me. Link to comment Share on other sites More sharing options...
blizzardof09 Posted August 20, 2011 Share Posted August 20, 2011 There have been many events this summer that have made it out to eastern LI. Most of them from my memory though have moved in from the north rather than the west. Aug 1 sticks out for me. I know due to the seabreeze/southeast winds storms do more times than not get ripped apart but its frustrating seeing some great storms to my west just die and not being able to enjoy the sight of them when they get here. SBUWX23 a lot of times this summer the storms from where I live have gone to the north or went offshore really just a luck of the draw thing I guess Link to comment Share on other sites More sharing options...
SBUWX23 Posted August 20, 2011 Share Posted August 20, 2011 I know due to the seabreeze/southeast winds storms do more times than not get ripped apart but its frustrating seeing some great storms to my west just die and not being able to enjoy the sight of them when they get here. SBUWX23 a lot of times this summer the storms from where I live have gone to the north or went offshore really just a luck of the draw thing I guess Alot of it has to due with storm structure and outflow processes. The outflow and sea breezes can really hurt the storm maintenance, but there are times when it can enhance it. Its challenging Link to comment Share on other sites More sharing options...
blizzardof09 Posted August 20, 2011 Share Posted August 20, 2011 Alot of it has to due with storm structure and outflow processes. The outflow and sea breezes can really hurt the storm maintenance, but there are times when it can enhance it. Its challenging so in other words a crap shoot right? lol Link to comment Share on other sites More sharing options...
nycsnow Posted August 20, 2011 Share Posted August 20, 2011 Upton still saying supercells, tomorrow should be interesting probaly a lot of wind damage reports, anyone think we get a tornado watch? Link to comment Share on other sites More sharing options...
Weathergun Posted August 20, 2011 Share Posted August 20, 2011 Upton still saying supercells, tomorrow should be interesting probaly a lot of wind damage reports, anyone think we get a tornado watch? Tornado watch is possible with high lol-level helicity/shear numbers and large-curved hodographs the models are showing now. Link to comment Share on other sites More sharing options...
earthlight Posted August 20, 2011 Share Posted August 20, 2011 There's a good chance of southeast wind development near the coast. The models have been hinting at a southeast surface wind direction for a few runs now. If this occurs the severe weather threat could be relegated to areas like Western NJ and PA as well as farther north into Western New England and south into the Mid Atlantic states. Link to comment Share on other sites More sharing options...
earthlight Posted August 20, 2011 Share Posted August 20, 2011 The NAM has been stubborn though, in keeping winds south and even southwest through 18z. Some of the high resolution models have a shortwave farther ahead of the main forcing which brings winds at the surface to a southeast direction. The SPC WRF is one of them. http://www.emc.ncep.noaa.gov/mmb/mpyle/cent4km/conus/12/today_1h_f33.gif Link to comment Share on other sites More sharing options...
CT Rain Posted August 20, 2011 Share Posted August 20, 2011 The NAM has been stubborn though, in keeping winds south and even southwest through 18z. Some of the high resolution models have a shortwave farther ahead of the main forcing which brings winds at the surface to a southeast direction. The SPC WRF is one of them. http://www.emc.ncep....oday_1h_f33.gif The 18z NAM is mixing out dews like crazy tomorrow afternoon. EWR has a 18z dew point of 15c. Something to watch since the model is showing a very substantial lowering of instability around 18z from NYC up to SW SNE. Link to comment Share on other sites More sharing options...
earthlight Posted August 20, 2011 Share Posted August 20, 2011 The 18z NAM is mixing out dews like crazy tomorrow afternoon. EWR has a 18z dew point of 15c. Something to watch since the model is showing a very substantial lowering of instability around 18z from NYC up to SW SNE. The SREF followed suit as well (or began the trend at 15z, with the NAM at 18z). The instability really tapers off to the north and east of Newark and even towards the NJ coast. Something to keep an eye on for sure. The shortwave ahead of the main forcing could be an issue. The earlier model runs had that feature coming through at 12z. Link to comment Share on other sites More sharing options...
CT Rain Posted August 20, 2011 Share Posted August 20, 2011 The SREF followed suit as well (or began the trend at 15z, with the NAM at 18z). The instability really tapers off to the north and east of Newark and even towards the NJ coast. Something to keep an eye on for sure. The shortwave ahead of the main forcing could be an issue. The earlier model runs had that feature coming through at 12z. If anything a S or SSE flow would favor higher dew points in those areas... and with SSTs so warm the marine influence this time of year is its most marginal. Sort of an odd setup tomorrow I'm not too excited up here... I think you guys have a better chance at seeing something significant. Link to comment Share on other sites More sharing options...
earthlight Posted August 20, 2011 Share Posted August 20, 2011 If anything a S or SSE flow would favor higher dew points in those areas... and with SSTs so warm the marine influence this time of year is its most marginal. Sort of an odd setup tomorrow I'm not too excited up here... I think you guys have a better chance at seeing something significant. It's interesting though..because a few of the models have clouds in here by 12-15z, with the winds turning southeast. It has to be that lead shortwave causing problems and the early morning convection/cloud advection. As usual these types of events are hail pullers in a forecasting sense...in this part of the country especially. The SSE flow is a killer on the coast...but can work magic just barely inland in advecting in good dew points. The seabreeze usually only gets so far. So this threat could really favor Western NJ and E PA down into the Mid Atlantic. I think we'll have to wait until the 00z models and higher resolution stuff comes in to get a better handle on the potential mixing of dew points..shortwave positioning/etc. The shear is pretty impressive and the mean trough is anomalous, too. If we can get a few hours of sun we should be good...barring any crap that gets going early in the day with the lack of an eml or favorable lapse rates. Link to comment Share on other sites More sharing options...
earthlight Posted August 21, 2011 Share Posted August 21, 2011 Top 15 analogs at all levels lead to this smoothed mean probability of a severe weather report tomorrow Link to comment Share on other sites More sharing options...
nycsnow Posted August 21, 2011 Share Posted August 21, 2011 SPC CONTINUES SLIGHT RISK FOR SEVERE THUNDERSTORMS FROM LATE SUNDAY MORNING INTO SUNDAY NIGHT. PEOPLE ARE URGED TO STAY TUNED FOR FURTHER UPDATES ON THE SEVERE POTENTIAL TOMORROW AS THE SITUATION BECOMES MORE FOCUSED TONIGHT AND SUNDAY MORNING. ALL SIGNS POINTING TOWARDS POTENTIAL FOR ISOLD-SCT SEVERE THUNDERSTORMS FROM LATE SUNDAY AFTERNOON INTO SUNDAY NIGHT...WITH SOME POTENTIAL FOR A MORE WIDESPREAD OUTBREAK. AMPLIFYING 500 HPA TROUGH DIGS SE INTO EASTERN GREAT LAKES BY SUNDAY EVENING...WITH STRONG 45-55 KT MID LEVEL JET ROUNDING ITS BASE AND ENTERING THE AREA. WILL ALSO BE RIGHT REAR QUADRANT OF 110 KT 250 HPA JET SUNDAY AFTERNOON AS WELL. IN ADDITION 25-30KT 950 HPA JET IS APPROACHING FROM THE SW BY SUNDAY EVENING. GENERAL AGREEMENT ON 1500-2500 J/KG MU CAPE IN LOWEST 1 KM SUNDAY AFTERNOON. HAVE VEERING...AND GENERALLY INCREASING FLOW FROM SFC-500 HPA...SO HAVE PLENTY OF SHEAR...WITH 35-45KT 0-6KM BULK SHEAR VECTORS AS A RESULT. NAM 0-1KM HELICITY VALUES SEEM SUSPECT ON THE HIGH SIDE...WHILE GFS VALUES SEEM LOW...WITH TRUTH LIKELY IN BETWEEN. GIVEN FORECAST CAPE AND SHEAR VALUES...HAVE BULK RICHARDSON NUMBERS OF MAINLY 25-50 BY SUNDAY AFTERNOON...FAVORING A MIX OF SUPERCELLS AND MULTICELLULAR CONVECTION. MAIN THREAT IS FROM STRONG GUSTY WINDS...WITH 500 HPA TEMPERATURES AROUND -10C AND WET BULB ZERO HEIGHTS FORECAST UP TO 12000 FT...MARGINAL CASE FOR SEVERE HAIL. TAKING A MIDDLE OF THE ROAD BETWEEN NAM AND GFS LOW LEVEL HELICITY/SHEAR MAKES THE CASE FOR ISOLATED TORNADOES BEING POSSIBLE AS WELL. ESPECIALLY NOTING LCL/S FORECAST TO FALL BELOW 1000 FT BY LATE AFTERNOON/EARLY EVENING. SUNDAY MORNING SHOULD START OUT DRY...WITH POSSIBLY SOME TSRA DEVELOPING OVER WESTERN 1/5 OF THE CWA (MAINLY NW OF NYC) LATE IN THE MORNING. COVERAGE SHOULD INCREASE OVER THE NW 1/2 OF THE CWA DURING THE AFTERNOON...WITH MORE ISOLD/SCT CONVECTION IN SE 1/2. SEVERE THREAT CONTINUES SUNDAY NIGHT AHEAD OF A COLD FRONT. GFS IS SLOW COMPARED TO NAM/ECMWF/CMC-REG/SREF AND ITS OWN ENSEMBLE MEAN...SO LEANED TOWARDS QUICKER SOLUTION WITH FRONT. STILL FORECASTED TO HAVE 1000-2000 J/KG MU CAPE AHEAD OF THE FRONT SUNDAY NIGHT...WITH VEERING SHEAR PROFILE...AND LOWERING WET BULB ZERO HEIGHTS...PLUS LOW LEVEL AND MID LEVEL JET CROSSING SOUTHERN/NORTHERN PARTS OF THE CWA RESPECTIVELY. ONLY NEGATIVE IS IT APPEARS WILL BE IN LEFT FRONT QUAD OF 110KT 250 HPA JET...SO THAT WILL HELP KEEP A LID ON THINGS...BUT GIVEN EXTENT OF LOW LEVEL MOISTURE AND INSTABILITY ALONG WITH INCREASING 0-6 KM SHEAR (PROGGED TO 45-55KT)...LOW TOPPED SEVERE STORMS STILL A STRONG RISK...BUT BECOMING LESS WIDESPREAD AS THE NIGHT PROGRESSES. ALSO MORE LIKELY TO EVOLVE TOWARDS A QLCS TYPE STRUCTURE AS STORMS/FRONT PROGRESS EAST. IN ADDITION TO SEVERE THREAT...THERE IS THE POTENTIAL FOR LOCALLY HEAVY RAINFALL AS WELL. SEE HYDRO SECTION OF AFD FOR DETAILS. Uptons take btw earthlight check you're pm Link to comment Share on other sites More sharing options...
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