bmc10 Posted June 9, 2011 Share Posted June 9, 2011 I'm worried now... I hope we don't run into the overhype, underperform situation again. No this is exactly what happens when we get a legitimate severe weather threat, it is not until a few hours before that SPC becomes excited. When they are talking about the threat for a few days in advance (such as the last setup) then it never materializes. I actually like the setup today. I think we have just enough shear and lift under the front to support storms. The advancing trough should provide just enough shear to ignite this very dynamically supportive and unstable environment that is present over our area. I think someone in NNJ, NEPA, or SNY gets rocked. Link to comment Share on other sites More sharing options...
hudsonvalley21 Posted June 9, 2011 Share Posted June 9, 2011 I'm worried now... I hope we don't run into the overhype, underperform situation again. Tor. prob.now up to 5% Link to comment Share on other sites More sharing options...
IsentropicLift Posted June 9, 2011 Author Share Posted June 9, 2011 Yea its not like alot of the models are bringing severe weather to the nyc metro area besides the hrrr, this might just be the case of the nws being safe with what's on the table today as far as potential severe weather with the best chance further to our north, I think so anyway they dont normally issue upgrades on convective outlooks just to be safe, they issue watches sometimes during marginal setups just to cover themselves. The general public has no clue that there is a moderate risk now for our area. All they know is that there is a chance for some afternoon thunderstorms. Some TV mets MAY have ussed stronger wording but I know Mr. G didn't this morning. Link to comment Share on other sites More sharing options...
tornadojay Posted June 9, 2011 Share Posted June 9, 2011 I'm still looking for what changed other than the HRRR going batty. Find me the trigger and I will join the party. me too.. from the weatherprediction site. Lifting Mechanisms for severe t-storms: 1. Frontal boundaries, dry lines and outflow boundaries (low level convergence) 2. Low level Warm Air Advection 3. Upslope flow 4. Low pressure system (synoptic and mesoscale) 5. Differential heating along soil, vegetation, soil moisture, land cover boundaries (low level convergence) 6. Low level moisture advection 7. Differential Positive Vorticity Advection, jet streak divergence (upper level divergence) 8. Gravity wave To me, it sounds like they are hedging their bets on Outflow boundaries and the cold front, of course. Link to comment Share on other sites More sharing options...
tornadojay Posted June 9, 2011 Share Posted June 9, 2011 SEVERE THUNDERSTORM COOKBOOK METEOROLOGIST JEFF HABY The following are the main ingredients for supercell thunderstorms. The more ingredients available, the more spectacular the storm will be once it is taken out of the oven. (1) Instability- Defined by the temperature stratification of the atmosphere. Instability increases by warming the low levels (PBL) and/or cooling the mid and upper levels (700 to 300 mb). It is most easily assessed by looking at thermodynamic parameters. The most important include the CAPE, LI, cap, and dewpoint depression between 700 and 500 mb. Dry air in the mid-levels combined with warm and moist air in the PBL will produce convective instability. (2) Moisture (high dewpoints)- The more moisture available, the more latent heat that can be released once storms develop. It is important to look for moisture advection hour by hour on a day severe weather is possible. The air is more unstable in regions of dewpoint maxima. Here is a guide to dewpoint values and the instability and latent heat they can provide: Greater than 75Incredibly juicy65-74Juicy55-64Semi-juicyLess than 55Low moisture content (3) Warm PBL temperatures- Air density decreases with increasing temperature. The greater the heating is during the day, the greater the instability of the atmosphere. Days with sunshine will be more convectively unstable than days with continuous cloud cover. The breaking of clouds on a day when severe weather has been forecast will increase the likelihood of severe weather. A temperature guide for buoyancy follows below (lift will determine if bouyancy is allowed to occur): 100+Incredibly buoyant (if dewpoint greater than 55)90-99+Extremely buoyant (if dewpoint greater than 55)80-89+Very buoyant (if dewpoint greater than 55)70-79 Fairly unstable (if dewpoint greater than 55)60-69 Marginal (if dewpoint greater than 55)Less than 60Positive temperature and dewpoint advection needed (4) Low level jet/ inflow- Strong low level winds will quickly advect warm and moist air into a region if it is associated with the low level jet. Unimpressive temperatures and dewpoints can change rapidly during the day via the low level jet. If winds are light in the PBL, severe weather is not as likely. Here are some low level jet wind values at 850 to keep in mind when analyzing: Greater than 70 knotsIncredibly fast advection50 to 69 knotsVery strong low level jet30 to 49 knotsDescent low level jet20 to 29 knotsMarginal low level jetLess than 20 knotsIll-defined low level jet (5) Strong surface to 700 millibar directional shear- Change in direction with height will cause horizontal vorticity which can lead to tornadic development. It also produces differential advection. Best case would be to have southeast wind at the surface transporting warm and moist air, a southwest or west wind at 700 millibar transporting dry air, and a northwesterly wind in the upper levels of the atmosphere. (6) Strong speed shear with height- This will cause updrafts to tilt in the vertical thus leading to supercell storms. Speed shear also causes tubes of horizontal vorticity, which can be ingested into thunderstorms. (7) Upper level Jet Stream- Use forecast models to determine the strength of the jet stream. The stronger the jet, the stronger the upper level forcing. Below is a guide to jet stream wind and upper level divergence (occurs in right rear and left front quadrant of a jet streak). Greater than 200 knotsIncredible divergence150 to 200 knotsLarge divergence100 to 149 knotsGood divergence70 to 99 knotsMarginal divergenceLess than 70 knotsSmall divergence (8) 500 millibar vorticity- Vorticity is a function of trough curvature, earth vorticity, and speed gradients. When using models to assess strength of vorticity you will notice a value is given for the VORT MAX. The higher the value, the higher the potential upper level divergence. Below is a guide to 500 millibar vorticity and upper level divergence. If the values of vorticity are being rapidly advected, divergence will "in the real world" be much more than if the winds through the vorticity maximum are stationary or moving slowly. 40+ Incredible divergence30+ Very large divergence20-29 Large divergenceTeens Descent divergenceLess than 12 Low but positive divergence Link to comment Share on other sites More sharing options...
TheTrials Posted June 9, 2011 Share Posted June 9, 2011 me too.. from the weatherprediction site. Lifting Mechanisms for severe t-storms: 1. Frontal boundaries, dry lines and outflow boundaries (low level convergence) 2. Low level Warm Air Advection 3. Upslope flow 4. Low pressure system (synoptic and mesoscale) 5. Differential heating along soil, vegetation, soil moisture, land cover boundaries (low level convergence) 6. Low level moisture advection 7. Differential Positive Vorticity Advection, jet streak divergence (upper level divergence) 8. Gravity wave To me, it sounds like they are hedging their bets on Outflow boundaries and the cold front, of course. on outflow boundaries. Everything just looks so displaced to the north. The instability is epic but we had that last week too with better helicity although the straight line wind threat is better this week. We shall see within a few hours. Link to comment Share on other sites More sharing options...
IsentropicLift Posted June 9, 2011 Author Share Posted June 9, 2011 Something sparked the HRRR to go with 90% convective probs for us Link to comment Share on other sites More sharing options...
TheTrials Posted June 9, 2011 Share Posted June 9, 2011 they dont normally issue upgrades on convective outlooks just to be safe, they issue watches sometimes during marginal setups just to cover themselves. The general public has no clue that there is a moderate risk now for our area. All they know is that there is a chance for some afternoon thunderstorms. Some TV mets MAY have ussed stronger wording but I know Mr. G didn't this morning. that dude is still alive? he has to be 100 by now. Link to comment Share on other sites More sharing options...
TheTrials Posted June 9, 2011 Share Posted June 9, 2011 Something sparked the HRRR to go with 90% convective probs for us 90% way west, not really for nyc metro, please be specific when you say us. Link to comment Share on other sites More sharing options...
IsentropicLift Posted June 9, 2011 Author Share Posted June 9, 2011 LI index now -12 over Orange county. What a day this will be if we can get initiation. Link to comment Share on other sites More sharing options...
hudsonvalley21 Posted June 9, 2011 Share Posted June 9, 2011 HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE NEW YORK NY 1251 PM EDT THU JUN 9 2011 ANZ335-338-CTZ005>010-NJZ002-NYZ067>071-177-179-101700- LONG ISLAND SOUND WEST OF NEW HAVEN CT/PORT JEFFERSON NY- NEW YORK HARBOR-NORTHERN FAIRFIELD-NORTHERN NEW HAVEN- NORTHERN MIDDLESEX-NORTHERN NEW LONDON-SOUTHERN FAIRFIELD- SOUTHERN NEW HAVEN-WESTERN PASSAIC-ORANGE-PUTNAM-ROCKLAND- NORTHERN WESTCHESTER-SOUTHERN WESTCHESTER-NORTHERN NASSAU- SOUTHERN NASSAU- 1251 PM EDT THU JUN 9 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR ATLANTIC COASTAL WATERS...SOUTHERN CONNECTICUT...NORTHEAST NEW JERSEY AND SOUTHEAST NEW YORK. .DAY ONE...THIS AFTERNOON AND TONIGHT. THE AREA IS UNDER A MODERATE RISK FOR SEVERE THUNDERSTORM DEVELOPMENT TODAY. ALTHOUGH THE PRIMARY THREATS WILL BE LARGE HAIL AND DAMAGING WINDS...THERE IS A CHANCE FOR AN ISOLATED TORNADO. IN ADDITION TO THE SEVERE THREAT...ANY STORMS THAT DO DEVELOP WILL BE CAPABLE OF PRODUCING TORRENTIAL RAINFALL AND AREAS OF FLASH FLOODING. Link to comment Share on other sites More sharing options...
IsentropicLift Posted June 9, 2011 Author Share Posted June 9, 2011 90% way west, not really for nyc metro, please be specific when you say us. way west?? how so it covers all of NJ, the next hour moves it right over the city itself. Link to comment Share on other sites More sharing options...
ag3 Posted June 9, 2011 Share Posted June 9, 2011 No this is exactly what happens when we get a legitimate severe weather threat, it is not until a few hours before that SPC becomes excited. When they are talking about the threat for a few days in advance (such as the last setup) then it never materializes. I actually like the setup today. I think we have just enough shear and lift under the front to support storms. The advancing trough should provide just enough shear to ignite this very dynamically supportive and unstable environment that is present over our area. I think someone in NNJ, NEPA, or SNY gets rocked. Agree 100%. Link to comment Share on other sites More sharing options...
tornadojay Posted June 9, 2011 Share Posted June 9, 2011 the upper level dynamics aren't very impressive. I mean, there's no strong shortwave with any particular wind maximas and no vorticity advection.. no upper level jet dyamics either.. we are going to be depedent on forcing mechanisms that are a bit more localized. Link to comment Share on other sites More sharing options...
tornadojay Posted June 9, 2011 Share Posted June 9, 2011 No this is exactly what happens when we get a legitimate severe weather threat, it is not until a few hours before that SPC becomes excited. When they are talking about the threat for a few days in advance (such as the last setup) then it never materializes. I actually like the setup today. I think we have just enough shear and lift under the front to support storms. The advancing trough should provide just enough shear to ignite this very dynamically supportive and unstable environment that is present over our area. I think someone in NNJ, NEPA, or SNY gets rocked. I hope there is shear. I'm not seeing it right now.. 850 and 500 winds are not very impressive and I'm not seeing the strong winds upstream... but I'm hoping for the best Link to comment Share on other sites More sharing options...
bmc10 Posted June 9, 2011 Share Posted June 9, 2011 I hope there is shear. I'm not seeing it right now.. 850 and 500 winds are not very impressive and I'm not seeing the strong winds upstream... but I'm hoping for the best Well it appears the more favorable dynamics still remain back west, but we should hope that as the front progresses eastward that the associated dynamics would fire storms later in the period. I think most guidance indicates more supportive mechanisms later today. Link to comment Share on other sites More sharing options...
ag3 Posted June 9, 2011 Share Posted June 9, 2011 New HRRR out to 4 hours and showing a nice line forming. Waiting for next few frames. Link to comment Share on other sites More sharing options...
IsentropicLift Posted June 9, 2011 Author Share Posted June 9, 2011 shear is increasing a tad Link to comment Share on other sites More sharing options...
ag3 Posted June 9, 2011 Share Posted June 9, 2011 Hour 5: Hour 6: Link to comment Share on other sites More sharing options...
ag3 Posted June 9, 2011 Share Posted June 9, 2011 Hour 6 1km. Strong storms: Link to comment Share on other sites More sharing options...
hudsonvalley21 Posted June 9, 2011 Share Posted June 9, 2011 I hope there is shear. I'm not seeing it right now.. 850 and 500 winds are not very impressive and I'm not seeing the strong winds upstream... but I'm hoping for the best It appears that there are 2 lines forming. One in central NY ant the other in extreme western NY. Vis loop. http://www.meteo.psu.edu/~gadomski/SAT_PA/anim8vis.html Link to comment Share on other sites More sharing options...
NJwinter23 Posted June 9, 2011 Share Posted June 9, 2011 I'm still looking for what changed other than the HRRR going batty. Find me the trigger and I will join the party. Aside from the chance a pre frontal trough spawns some earlier stuff, the cold front will push through tonight, and I would think there will be plenty instability left over from today to sustain the threat even if it is in the middle of the night? The wind shear is my bigger concern, but 30 kts usually does it. Link to comment Share on other sites More sharing options...
IsentropicLift Posted June 9, 2011 Author Share Posted June 9, 2011 storms are exploding over upstate NY Link to comment Share on other sites More sharing options...
HM Posted June 9, 2011 Share Posted June 9, 2011 Aside from the chance a pre frontal trough spawns some earlier stuff, the cold front will push through tonight, and I would think there will be plenty instability left over from today to sustain the threat even if it is in the middle of the night? The wind shear is my bigger concern, but 30 kts usually does it. Agreed. Any CAPE/thermodynamic parameter you look at couldn't be any higher in this area. We still have 7 hours left for the best acceleration and I am sure we'll develop a nice cold pool with these. Link to comment Share on other sites More sharing options...
IsentropicLift Posted June 9, 2011 Author Share Posted June 9, 2011 say hello to 5500 SBCAPE Yankees game in serious jepordy tonight. Link to comment Share on other sites More sharing options...
ag3 Posted June 9, 2011 Share Posted June 9, 2011 We probably go into a watch soon. Link to comment Share on other sites More sharing options...
IsentropicLift Posted June 9, 2011 Author Share Posted June 9, 2011 MUCAPE now over 5000 J/KG as well, this is dream instability, no model showed this Link to comment Share on other sites More sharing options...
NJwinter23 Posted June 9, 2011 Share Posted June 9, 2011 Agreed. Any CAPE/thermodynamic parameter you look at couldn't be any higher in this area. We still have 7 hours left for the best acceleration and I am sure we'll develop a nice cold pool with these. Awesome, should be fun to watch unfold as always. Hopefully something good makes it down my way, though I'll do without the hatched hail lol. Link to comment Share on other sites More sharing options...
HM Posted June 9, 2011 Share Posted June 9, 2011 Awesome, should be fun to watch unfold as always. Hopefully something good makes it down my way, though I'll do without the hatched hail lol. Hatched hail is a rarity and I'm not sure if I can recall an instance in the past where we were in one. But I am sure it is more recent than I can remember. You've had enough hail there in Monmouth county for one year. Link to comment Share on other sites More sharing options...
tornadojay Posted June 9, 2011 Share Posted June 9, 2011 another watch box out, but that one is west of us.. i guess a bit later. Link to comment Share on other sites More sharing options...
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