Dark Energy Posted May 30, 2011 Share Posted May 30, 2011 SPC meso maps show great ML lapse rates over NJ at least ahead of the MCS. Then there is good MUCAPE as well. This thing could hold true after all. No warnings on it since earlier, so we'll see if it does pulse up again. It will enter a great environment for activity soon. Link to comment Share on other sites More sharing options...
tmagan Posted May 30, 2011 Share Posted May 30, 2011 Got to admit, I'm impressed that this MCC held together. Link to comment Share on other sites More sharing options...
NJwinter23 Posted May 30, 2011 Share Posted May 30, 2011 MCS is clearly strengthening too as it goes into a still unstable environment. Warnings out now for northwest NJ/ne PA MESOSCALE DISCUSSION 1026 NWS STORM PREDICTION CENTER NORMAN OK 0246 AM CDT MON MAY 30 2011 AREAS AFFECTED...SERN NY/ERN PA/NRN NJ CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 300746Z - 300945Z THREAT FOR ISOLATED DAMAGING WINDS IS EXPECTED FOR THE NEXT FEW HOURS...BUT WW IS NOT BEING CONSIDERED ATTM. LATEST RADAR LOOP SHOWS A SMALL BOWING LINE OF STORMS/MCS MOVING ESEWD AT 40 KT ACROSS NERN PA AND ADJACENT FAR SRN NY. THE STORMS ARE OCCURRING WITHIN THE CIRCULATION OF A LONG-LIVED MCV FROM EARLIER CONVECTION WHICH INITIATED IN THE MIDWEST AND CONTINUED EWD ACROSS THE OH VALLEY/GREAT LAKES REGION AND NOW INTO NY/PA. WHILE STORMS ARE SLIGHTLY ELEVATED ABOVE A SHALLOW/STABLE BOUNDARY LAYER...AMPLE ELEVATED INSTABILITY AND SUFFICIENT SHEAR EXIST FOR A CONTINUATION OF ORGANIZED STORMS -- AND LIMITED THREAT FOR A FEW ISOLATED GUSTS TO PENETRATE THE BOUNDARY LAYER AND PRODUCE DAMAGING SURFACE WINDS. HOWEVER...WITH THE THREAT LIMITED AREALLY...TEMPORALLY...AND IN DEGREE...WW IS NOT ANTICIPATED ATTM. Link to comment Share on other sites More sharing options...
Weathergun Posted May 30, 2011 Share Posted May 30, 2011 Warnings up and down that line: BULLETIN - EAS ACTIVATION REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE NEW YORK NY 523 AM EDT MON MAY 30 2011 THE NATIONAL WEATHER SERVICE IN UPTON NY HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... WESTCHESTER COUNTY IN SOUTHEAST NEW YORK... ROCKLAND COUNTY IN SOUTHEAST NEW YORK... PUTNAM COUNTY IN SOUTHEAST NEW YORK... ORANGE COUNTY IN SOUTHEAST NEW YORK... * UNTIL 615 AM EDT... * AT 522 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS OF 60 MPH. THESE STORMS WERE LOCATED ALONG A LINE EXTENDING FROM 13 MILES NORTHWEST OF WALDEN TO FLORIDA TO 6 MILES SOUTHEAST OF UNIONVILLE...OR ALONG A LINE EXTENDING FROM ELLENVILLE TO 6 MILES SOUTHWEST OF GOSHEN TO 9 MILES WEST OF WARWICK...AND MOVING EAST AT 45 MPH. * OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO CHESTER...MONTGOMERY...GREENWOOD LAKE...MONROE...HARRIMAN... GARDNERTOWN...NEWBURGH...NEW WINDSOR...WEST POINT...COLD SPRING... POMONA...HAVERSTRAW...FAHNESTOCK STATE PARK...PEEKSKILL... MAHOPAC...CARMEL...LAKE CARMEL...YORKTOWN HEIGHTS AND BREWSTER BULLETIN - EAS ACTIVATION REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 511 AM EDT MON MAY 30 2011 THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... LEHIGH COUNTY IN EASTERN PENNSYLVANIA... THIS INCLUDES THE CITY OF ALLENTOWN... NORTHAMPTON COUNTY IN EASTERN PENNSYLVANIA... THIS INCLUDES THE CITY OF EASTON... SOUTHEASTERN CARBON COUNTY IN NORTHEAST PENNSYLVANIA... SOUTH CENTRAL MONROE COUNTY IN NORTHEAST PENNSYLVANIA... MORRIS COUNTY IN NORTHERN NEW JERSEY... THIS INCLUDES THE CITY OF MORRISTOWN... NORTHERN SOMERSET COUNTY IN NORTHERN NEW JERSEY... THIS INCLUDES THE CITY OF SOMERVILLE... HUNTERDON COUNTY IN NORTHWEST NEW JERSEY... SOUTH CENTRAL SUSSEX COUNTY IN NORTHWEST NEW JERSEY... WARREN COUNTY IN NORTHWEST NEW JERSEY... NORTHWESTERN BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA... * UNTIL 615 AM EDT * AT 507 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS OF 60 MPH. THESE STORMS WERE LOCATED ALONG A LINE EXTENDING FROM COLUMBIA TO WIND GAP TO SLATINGTON TO WANAMAKERS TO 14 MILES NORTHWEST OF WANAMAKERS...AND MOVING SOUTHEAST AT 40 MPH. * SEVERE THUNDERSTORMS WILL BE NEAR... NEFFS...SCHNECKSVILLE...BELFAST AND BATH AROUND 515 AM EDT... HOPE...PERKASIE...COFFEETOWN AND TATAMY AROUND 520 AM EDT... WANAMAKERS AND FORKS AROUND 525 AM EDT... PRECAUTIONARY/PREPAREDNESS ACTIONS... THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER... PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS. Link to comment Share on other sites More sharing options...
NJwinter23 Posted May 30, 2011 Share Posted May 30, 2011 Probably some spectacular views as this line approaches areas right at sunrise. Link to comment Share on other sites More sharing options...
Weathergun Posted May 30, 2011 Share Posted May 30, 2011 SPS now for NYC metro: Looks like it's starting to weaken on it's way to NYC. Still some strong storms: Link to comment Share on other sites More sharing options...
Mr Torchey Posted May 30, 2011 Share Posted May 30, 2011 line is pulsing back up again last couple frames. Link to comment Share on other sites More sharing options...
earthlight Posted May 30, 2011 Author Share Posted May 30, 2011 Man, I really ate sh** with forecasting that MCS. I had something equivilant to a small heart attack at 615 when s tremendously loud clap of thunder woke me up. Nice forecast by those who had it coming through here. Link to comment Share on other sites More sharing options...
Isotherm Posted May 30, 2011 Share Posted May 30, 2011 Man, I really ate sh** with forecasting that MCS. I had something equivilant to a small heart attack at 615 when s tremendously loud clap of thunder woke me up. Nice forecast by those who had it coming through here. Yeah I woke up to hvy rain at 630, figured it had to be the MCS, checked the radar and it was. Pretty good boomers associated with it as well. Skies clearing now to my west. Link to comment Share on other sites More sharing options...
bluewave Posted May 30, 2011 Share Posted May 30, 2011 This MCS had the best structure that I can remember for an early morning May MCS in our area. METAR KLGA 301051Z 30015G26KT 2SM +TSRA BR SCT015 BKN022 OVC042CB 21/19 A3005 RMK AO2 PK WND 30030/1038 TSB44RAB33 SLP177 OCNL LGTIC OHD TS OHD MOV E P0014 T02110189 Link to comment Share on other sites More sharing options...
Allsnow Posted May 30, 2011 Share Posted May 30, 2011 Forky ftw Link to comment Share on other sites More sharing options...
Isotherm Posted May 30, 2011 Share Posted May 30, 2011 Hopefully a sign of things to come svr wise this summer. Link to comment Share on other sites More sharing options...
earthlight Posted May 30, 2011 Author Share Posted May 30, 2011 Forky ftw and dark energy anyway, back to Wednesday...I think the SPC outlook was fair. The guidance continues to look impressive. I want to see the EML hold steady on the guidance for a few more cycles--it's incredibly important. More often than not as the events approach we lose the EML signal. There is a very strong correlation between an EML and big severe weather events here. Link to comment Share on other sites More sharing options...
Allsnow Posted May 30, 2011 Share Posted May 30, 2011 Sorry for my lack of knowledge in this subject but what is a EML? My fear for Wednesday is as we get closer to the time frame things become less appealing. Link to comment Share on other sites More sharing options...
earthlight Posted May 30, 2011 Author Share Posted May 30, 2011 Sorry for my lack of knowledge in this subject but what is a EML? My fear for Wednesday is as we get closer to the time frame things become less appealing. EML is an Elevated Mixed Layer...usually associated with stronger mid level lapse rates. The EML is the key around this part of the country in getting organized, established deep severe convection. It allows the cape to get higher despite the capping--and with the capping, it can keep the convection more discrete so that you can get individual updraft development and the potential to maximize the available low level shear (if it's there)...and have greater threats for damaging winds, very large hail, and tornadoes. The EML more often that not is much more well established in the plains with much more favorable lapse rates. Unfortunately it's usually a real hard task to get a well established EML up into this part of the country, and more often than not when it is modeled, it doesn't verify due to a plethora of things..such as morning convection, decaying MCS's that release enough latent heat to kill the lapse rates, etc. As I mentioned earlier the interesting thing about this synoptic setup is that it is not a typical cold frontal setup for our region. The shortwave is well back to the northwest--but height falls are spreading east/southeast. As a result the 10m wind flow is westerly as opposed to our typical southerly/southeasterly flow ahead of a cold front. This is allowing the advection of the eml and more favorable lapse rates as well as inhibiting the marine air from getting involved. As it stands now there's a good chance of organized severe convection moving from northwest to southeast on Wednesday. We'll have to carefully watch the lapse rates and EML quality as well as the effective shear and wind fields forecast on the SREF...they have been getting better the past few ensemble cycles. Link to comment Share on other sites More sharing options...
Allsnow Posted May 30, 2011 Share Posted May 30, 2011 EML is an Elevated Mixed Layer...usually associated with stronger mid level lapse rates. The EML is the key around this part of the country in getting organized, established deep severe convection. It allows the cape to get higher despite the capping--and with the capping, it can keep the convection more discrete so that you can get individual updraft development and the potential to maximize the available low level shear (if it's there)...and have greater threats for damaging winds, very large hail, and tornadoes. The EML more often that not is much more well established in the plains with much more favorable lapse rates. Unfortunately it's usually a real hard task to get a well established EML up into this part of the country, and more often than not when it is modeled, it doesn't verify due to a plethora of things..such as morning convection, decaying MCS's that release enough latent heat to kill the lapse rates, etc. As I mentioned earlier the interesting thing about this synoptic setup is that it is not a typical cold frontal setup for our region. The shortwave is well back to the northwest--but height falls are spreading east/southeast. As a result the 10m wind flow is westerly as opposed to our typical southerly/southeasterly flow ahead of a cold front. This is allowing the advection of the eml and more favorable lapse rates as well as inhibiting the marine air from getting involved. As it stands now there's a good chance of organized severe convection moving from northwest to southeast on Wednesday. We'll have to carefully watch the lapse rates and EML quality as well as the effective shear and wind fields forecast on the SREF...they have been getting better the past few ensemble cycles. Thanks John..... Link to comment Share on other sites More sharing options...
Isotherm Posted May 30, 2011 Share Posted May 30, 2011 In addition to John's excellent post, take a few minutes to read this page, very informative: http://www.bangladeshtornadoes.org/EML/emlpage.html EML is one of the cornerstones to severe outbreaks in the Plains, basically acts like a lid on a pot, containing the heat/energy until a rupture occurs (allowing the convection to be more intense). Link to comment Share on other sites More sharing options...
Isotherm Posted May 30, 2011 Share Posted May 30, 2011 In addition to John's excellent post, take a few minutes to read this page, very informative: http://www.banglades...ML/emlpage.html EML is one of the cornerstones to severe outbreaks in the Plains, basically acts like a lid on a pot, containing the heat/energy until a rupture occurs (allowing the convection to be more intense). If you scroll half-way down the page, there are EML examples for the east coast w/ soundings. More often than not, our tornadic outbreaks have good EML presentation, as well as other major severe outbreaks. Look for that mid level drying in conjunction with low level moisture advection. As John noted the set up for Wednesday is potentially a favorable one for us as winds are NWLY aloft, meaning sfc winds only back to SWLY rather than S/SELY with SWLY flow aloft svr events. Impressive thermodynamics too as we all know with 90F temps and 70F Td's. Link to comment Share on other sites More sharing options...
bluewave Posted May 30, 2011 Share Posted May 30, 2011 Michael Ekster and Peter Banacos put together a really great presentation on the EML and NE severe outbreaks. http://docs.google.c..._rgTfa7JsUvdfIw Link to comment Share on other sites More sharing options...
Weathergun Posted May 30, 2011 Share Posted May 30, 2011 Michael Ekster and Peter Banacos put together a really great presentation on the EML and NE severe outbreaks. http://docs.google.c..._rgTfa7JsUvdfIw I read that. Excellent presentation. Easy to understand and very informative. Link to comment Share on other sites More sharing options...
Dark Energy Posted May 30, 2011 Share Posted May 30, 2011 actually, there were 2 MCS's last night. The first one pointed out by forky, went well to our north into upstate ny. The one that got us, formed on its outflow boundary a little to the southwest. Since that 2nd MCS started out more to the SW, it was able to push right into the area. Link to comment Share on other sites More sharing options...
earthlight Posted May 30, 2011 Author Share Posted May 30, 2011 The GFS has increased the EML on it's latest run and has very favorable lapse rates. The SREF agrees and has some very high probs on it's latest run for Wednesday. Link to comment Share on other sites More sharing options...
Thunderdude Posted May 30, 2011 Share Posted May 30, 2011 The storms weaken before they hit me but still had some thunder but didn't get much of the way of any heavy rain. But hopefully the back door cold front coming tonight doesn't mess things up for Wednesday and marine air and other factors doesn't get in the way. So the models look good and I like what I see but I worry about the bust. Link to comment Share on other sites More sharing options...
IsentropicLift Posted May 30, 2011 Share Posted May 30, 2011 I think we have a very good chance at a moderate risk with 45% wind probs, 30% hail probs and 5% tornado probs. Early discrete cells should transition into one or more squall lines. Plus historically we do well around Memorial Day for some reason. Probably because this is usually the final showdown between warm humid air to the south and cool arctic dry air still bottled up over northern New England. Link to comment Share on other sites More sharing options...
earthlight Posted May 31, 2011 Author Share Posted May 31, 2011 One potential major caveat to this potential widespread/significant outbreak of severe weather is the somewhat lacking 0-6km shear parameters in our area. These are much more favorable just a hair to our north, even over Northern New Jersey, Southeast New York, and especially into Southern New England. In severe convection, shear rules the yard...every time. You can often have plenty of favorable thermodynamics and get nothing but pulsers without the right amount of shear. It's especially magnified this time, with the models increasing the definition of the EML as the event approaches (the new 15z SREF actually steepened the lapse rates quite a bit Wednesday morning & afternoon which is not a common occurrence). Should the better shear stay far to the north--the best potential for discrete supercells (owing to the eml and capping) will stay to the north as well, over Western CT/Western MA and vicinity. Still, the mid level height falls are impressive and the wind fields and speed shear are all there to initiate convection in our area. It's just a matter of whether it will be more multicelluar convection with hail and wind threats, or discrete supercellular convection with potential for isolated to scattered tornadoes given the rather impressive hodographs and low level turning. Link to comment Share on other sites More sharing options...
earthlight Posted May 31, 2011 Author Share Posted May 31, 2011 The new 21z SREF is much more favorable across the board. The EML looks better and at 48 hours there's a 70% or greater chance of a 700-500mb lapse rate of 7.0 or greater for a good majority of the area. In addition the thermodynics are more than favorable..with 3000j/kg of mixed layer CAPE over Central and Northern New Jersey and 2500 j/kg towards New York City and Southeast New York. The shear has improved this run, too, with 30-40kts of 0-6km bulk shear on the ensemble means. The significant severe weather parameter (craven brooks) is at 5000..indicative of the potential for a pretty big event. Link to comment Share on other sites More sharing options...
earthlight Posted May 31, 2011 Author Share Posted May 31, 2011 One thing that's a bit disconcerting, and worth discussing, is the NAM bringing through a mid level front earlier in the day..especially through northern sections of the area. It's also reflecting on the surface with a 10m wind shift to westerly...with the dry mid levels..would have the event over by 18z and keep the convection much less impressive. The GFS is slower--and is seemingly pointing towards a potential widespread severe weather event (the 18z run). Never a dull moment in forecasting severe weather here.. Link to comment Share on other sites More sharing options...
NJwinter23 Posted May 31, 2011 Share Posted May 31, 2011 i'll take my chances with steep mid-level lapse rates/ EML over some other potentially lacking parameters. Hopefully we can start from there Link to comment Share on other sites More sharing options...
earthlight Posted May 31, 2011 Author Share Posted May 31, 2011 i'll take my chances with steep mid-level lapse rates/ EML over some other potentially lacking parameters. Hopefully we can start from there Totally agree...00z GFS still looks very good with the EML and does not have the earlier 10m wind shift and mid level front that the NAM has...still signaling a big event. Link to comment Share on other sites More sharing options...
Dark Energy Posted May 31, 2011 Share Posted May 31, 2011 in my book, all you need is 30 kt of 0-6 km bulk shear. if we can get that and the EML, we'll be fine. Link to comment Share on other sites More sharing options...
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