phlwx Posted May 31, 2012 Share Posted May 31, 2012 As for the threat overall, I'm still conditionally optimistic. I can recall more warm front busts that busted south than busted north. I think Maryland is game but I'm not so sure we are up here (although this could change). That said, those are good dynamics for a Plains set-up (well one in June anyway), let alone an EC one, with a 50-knot LLJ at 925 mb and 850 mb and good veering with height. Remember that backed surface flow is going to mean we get a wind off the ocean. Even with the ridiculously warm SSTs we have up here, that it still a potentially-stabilizing marine layer. Again this is another reason why central MD might make out better than SE PA. I agree completely. I would also add Lancaster, Harrisburg, and York are in a prime spot as well...they typically do well in these types of setups and I think they probably get hammered pretty hard tomorrow around dinner time. I'm not sold at all on Philly or NJ...I think the timing stinks for us and I think the wind trajectory is a bit too off the water to get us instability in the city and east. That said, could be a gusty round of thunder locally. Link to comment Share on other sites More sharing options...
tombo82685 Posted May 31, 2012 Share Posted May 31, 2012 I agree completely. I would also add Lancaster, Harrisburg, and York are in a prime spot as well...they typically do well in these types of setups and I think they probably get hammered pretty hard tomorrow around dinner time. I'm not sold at all on Philly or NJ...I think the timing stinks for us and I think the wind trajectory is a bit too off the water to get us instability in the city and east. That said, could be a gusty round of thunder locally. yea the lower susq valley looks game on. This could be another event where we get a weakening line of storms coming in. You can see it on the models esp the nam. If this event had better timing, it could of been one of the better setups we have seen in a while. Will also depend how far north that wf gets to. The nam continues to slow the progresion of the front which isnt good for svr weather, crosses it around midnight.. Link to comment Share on other sites More sharing options...
Voyager Posted May 31, 2012 Share Posted May 31, 2012 Allentown/Tamaqua too far north? Link to comment Share on other sites More sharing options...
Rainshadow Posted May 31, 2012 Share Posted May 31, 2012 I got a quick flutter in my heart. Then I remembered yesterday. lol from the discussion...: "perhaps even a tornado threat". i'm stocking up on glue to sniff so i'm ready for friday. To be fair about the other day, the spc discussion about tornadoes was focusing on the NY Hudson Valley eastward. Its been pretty well stated about the potential with this event overall and the probable limitations in our area for tomorrow. Link to comment Share on other sites More sharing options...
NeffsvilleWx Posted May 31, 2012 Share Posted May 31, 2012 I would also add Lancaster, Harrisburg, and York are in a prime spot as well yea the lower susq valley looks game on. Hazardous Weather Outlook HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE STATE COLLEGE PA 241 AM EDT THU MAY 31 2012 PAZ035-036-056-057-059-063>066-010645- FULTON-FRANKLIN-PERRY-DAUPHIN-LEBANON-CUMBERLAND-ADAMS-YORK- LANCASTER- 241 AM EDT THU MAY 31 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA. .DAY ONE...TODAY AND TONIGHT. HAZARDOUS WEATHER IS NOT EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY. THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FRIDAY AFTERNOON AND EVENING. STORMS WILL LIKELY CONTAIN HEAVY DOWNPOURS WITH INTENSE RAINFALL RATES...POSSIBLY RESULTING IN LOCALIZED FLOODING. DAMAGING WINDS AND LARGE HAIL WILL BE THE PRIMARY SEVERE THUNDERSTORM HAZARDS. HOWEVER...THERE WILL BE AN ELEVATED CONDITIONAL THREAT FOR ISOLATED TORNADOES. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS LIKELY ON FRIDAY AFTERNOON AND EVENING. Link to comment Share on other sites More sharing options...
chubbs Posted May 31, 2012 Share Posted May 31, 2012 From 1AM SPC outlook SOME SUPERCELLS...INCLUDING A TORNADO THREAT...COULD OCCUR MAINLY ACROSS VA/DELMARVA REGION INTO SOUTHERN PA/NJ PROVIDED 1/ SUFFICIENT DESTABILIZATION OCCURS NEAR THE WARM FRONT AND 2/ SEMI-DISCRETE DEVELOPMENT OCCURS AHEAD OF THE COLD FRONT WHERE A LINEAR MODE SHOULD BE MORE DOMINANT. SOMEWHAT HIGHER PROBABILITIES/PERHAPS EVEN A CATEGORICAL MODERATE RISK MIGHT BE WARRANTED IN SUBSEQUENT CONVECTIVE OUTLOOKS. Link to comment Share on other sites More sharing options...
SmokeEater Posted May 31, 2012 Share Posted May 31, 2012 Hazardous Weather Outlook HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE STATE COLLEGE PA 241 AM EDT THU MAY 31 2012 PAZ035-036-056-057-059-063>066-010645- FULTON-FRANKLIN-PERRY-DAUPHIN-LEBANON-CUMBERLAND-ADAMS-YORK- LANCASTER- 241 AM EDT THU MAY 31 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA. .DAY ONE...TODAY AND TONIGHT. HAZARDOUS WEATHER IS NOT EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY. THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FRIDAY AFTERNOON AND EVENING. STORMS WILL LIKELY CONTAIN HEAVY DOWNPOURS WITH INTENSE RAINFALL RATES...POSSIBLY RESULTING IN LOCALIZED FLOODING. DAMAGING WINDS AND LARGE HAIL WILL BE THE PRIMARY SEVERE THUNDERSTORM HAZARDS. HOWEVER...THERE WILL BE AN ELEVATED CONDITIONAL THREAT FOR ISOLATED TORNADOES. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS LIKELY ON FRIDAY AFTERNOON AND EVENING. Good chance I'll be out your way come Friday afternoon. Link to comment Share on other sites More sharing options...
NeffsvilleWx Posted May 31, 2012 Share Posted May 31, 2012 Good chance I'll be out your way come Friday afternoon. if things look like they're coming together i might just have to try to take a day off. Link to comment Share on other sites More sharing options...
NeffsvilleWx Posted May 31, 2012 Share Posted May 31, 2012 Dr Forbes posted his initial TORCON forecast for Friday: Friday, June 1 AL south - 2 DC - 4 DE - 4 FL panhandle - 2 GA east-central, south - 2 MD east - 4 MD central - 2 to 3 NC central, east - 2 NJ north - 2 NJ south - 3 PA southeast - 4 SC central, east - 2 VA north - 4 VA south-central, east - 2 to 3 Other areas - 1 or less a 4 or higher in PA does not happen often at all Link to comment Share on other sites More sharing options...
Quakertown needs snow Posted May 31, 2012 Share Posted May 31, 2012 Guess I'm the one who is hoping for no tornado's in the area, especially populated areas. Link to comment Share on other sites More sharing options...
snowlurker Posted May 31, 2012 Share Posted May 31, 2012 Guess I'm the one who is hoping for no tornado's in the area, especially populated areas. Count me in as rooting against them. I could go for a light show and heavy rain, but no twisters. Link to comment Share on other sites More sharing options...
mappy Posted May 31, 2012 Share Posted May 31, 2012 Just wanted to drop in from the MA and thank Tombo for that informative post. Good luck to you guys north of me! Link to comment Share on other sites More sharing options...
tombo82685 Posted May 31, 2012 Share Posted May 31, 2012 It does appear that the Friday system is looking more and more interesting, but I am not quite sold on a decent severe thunderstorm threat for our area. Despite rather impressive wind fields overspreading the area, the timing is what may be against us. It looks like the best ascent and wind fields arrive after 00z Saturday and the gist of the guidance has what instabilty develops lowering during the night. I see the new 00z NAM has a 925 mb jet of 40-50 knots moving across most of the area after 00z Saturday. The southeasterly low-level inflow may also allow lower clouds to arrive sooner, cutting off the surface based CAPE. This could be an event where a convective line develops to the west and then it turns into not having much lightning with it as it becomes more low-topped with an eastward extent. This could be maintained through the night despite lowering instability due to decent height falls and a strengthening wind field. music to lee's ears Link to comment Share on other sites More sharing options...
NeffsvilleWx Posted May 31, 2012 Share Posted May 31, 2012 Guess I'm the one who is hoping for no tornado's in the area, especially populated areas. No one wants to see tornado's in population centers. I'd love to see one in the middle of some farmland though. Plenty of that in my neck of the woods. Link to comment Share on other sites More sharing options...
greg ralls Posted May 31, 2012 Share Posted May 31, 2012 Even if you're obsessed with tornadoes, that doesn't mean you want to see one skipping through the Main Line or something. Anyone remember the PDS Tornado Watch for our area from around 10 years ago or so? I think it was a Saturday. Nothing happened, thankfully, but that's still the only time I remember truly thinking I might get to see a strong tornado. I remember typing in my zip code on the NWS site and there was a picture of a tornado for that day's weather, and the text said something like "Destructive tornadoes possible." Link to comment Share on other sites More sharing options...
Boch23 Posted May 31, 2012 Share Posted May 31, 2012 No one wants to see tornado's in population centers. I'd love to see one in the middle of some farmland though. Plenty of that in my neck of the woods. I would have to believe this is the thought of most people on the board when they talk about wanting torandoes. Link to comment Share on other sites More sharing options...
stormspotterlive Posted May 31, 2012 Share Posted May 31, 2012 Even if you're obsessed with tornadoes, that doesn't mean you want to see one skipping through the Main Line or something. Anyone remember the PDS Tornado Watch for our area from around 10 years ago or so? I think it was a Saturday. Nothing happened, thankfully, but that's still the only time I remember truly thinking I might get to see a strong tornado. I remember typing in my zip code on the NWS site and there was a picture of a tornado for that day's weather, and the text said something like "Destructive tornadoes possible." I believe I recall hearing about the PDS watch on the news that day of course this is back when warning were by a whole county not by a storm and its path like now a days. Link to comment Share on other sites More sharing options...
tombo82685 Posted May 31, 2012 Share Posted May 31, 2012 not as impressed with this setup as i was yesterday. Models continue to back off on the instability for the region. I cab\n definitely see some svr weather esp west of the region, which will weaken some coming east. Timing of the front looks later also than yesterday, Link to comment Share on other sites More sharing options...
NeffsvilleWx Posted May 31, 2012 Share Posted May 31, 2012 Eric Horst's latest special weather disco: Noon Thursday, May 31: Textbook set up for severe storms tomorrow...from central PA southward through most of VA. Some tornadoes are possible. Developing.... He's usually pretty conservative. Link to comment Share on other sites More sharing options...
stormspotterlive Posted May 31, 2012 Share Posted May 31, 2012 Looks to me despite the lack of Instability wind will be a threat for the area with storms due to high shear. Wild card will be how strong the storms are as they come into our area. And as stated in the NWS AFD if the storms can manage to pass the warm front where we are continuing to find very decent shear in place for storms to work with on the models it would support at least a marginal damaging wind threat . Obviously if the warm front ends up more north there would be a greater tornado Hail and wind threat could set up in the area. Link to comment Share on other sites More sharing options...
SouthernNJ Posted May 31, 2012 Share Posted May 31, 2012 With the topic of tornadoes being discussed lately, it should be pointed out that today is the 14th anniversary of possibly the strongest tornado to impact the Mt. Holly CWA since it became an office. The Lyons F3 struck at 9:10 PM on May 31, 1998 and did severe damage to the borough, among other areas along its 8.3 mile path. A tornado warning was issued 23 minutes before the tornado touched down, and 33 minutes before it hit Lyons. As a result, there were no fatalities and just seven injuries. Link to comment Share on other sites More sharing options...
Boch23 Posted May 31, 2012 Share Posted May 31, 2012 Fully prepared for a redux of tuesday night. 30% expanded more north and west and 15% to the north and east reduced to about slightly north of philly on the latest outlook. Anytime I'm on the edge of slight risk I just expect nothing imby. Link to comment Share on other sites More sharing options...
LMolineuxLM1 Posted May 31, 2012 Share Posted May 31, 2012 Need I say gas station island effect maybe again? Murphys law. Next weeks cold pool pop-ups to the rescue for filming? Link to comment Share on other sites More sharing options...
NeffsvilleWx Posted May 31, 2012 Share Posted May 31, 2012 Latest from SPC: AN AREA OF STRONG HEIGHT FALLS...ON THE ORDER OF 60-90M...WILL OVERSPREAD THE OH VALLEY DURING THE DAY FRIDAY AS SLIGHTLY NEGATIVE TILTED UPPER TROUGH AXIS PROGRESSES TO A POSITION FROM LOWER MI...ARCING SEWD TO SC BY 02/00Z. AN EXPANSIVE AREA OF LARGE SCALE ASCENT IS EXPECTED TO OVERSPREAD THE REGION AHEAD OF THIS UPPER DIFFLUENT TROUGH AND SHOULD PROVE SUPPORTIVE OF WIDESPREAD CONVECTION ALONG ADVANCING COLD FRONT AS IT SURGES EWD. THUNDERSTORMS SHOULD BE ONGOING EARLY IN THE PERIOD ALONG THE COLD FRONT FROM OH...SWD INTO NRN GA. WHILE STRONG SHEAR WILL COINCIDE WITH THIS ACTIVITY IN ALL LIKELIHOOD BROKEN LINEAR TSTM SEGMENTS SHOULD BE MOSTLY NON-SEVERE...OR PERHAPS MARGINALLY SEVERE AT DAYBREAK. MAIN LIMITING FACTOR FOR SEVERE EARLY IN THE PERIOD WILL BE DUE TO MEAGER INSTABILITY. HOWEVER...BOUNDARY LAYER HEATING SHOULD AID IN AIR MASS DESTABILIZATION BY 18Z AND SUFFICIENT BUOYANCY WILL DEVELOP FOR ROBUST UPDRAFTS WITHIN AN ENVIRONMENT MORE THAN SUFFICIENTLY SHEARED FOR ORGANIZATION. IN FACT...FORECAST SOUNDINGS SUGGEST ROTATING UPDRAFTS/SUPERCELL STRUCTURES ARE POSSIBLE. GIVEN THE AFOREMENTIONED LARGE SCALE SUPPORT...IT APPEARS A STRONGLY FORCED SQUALL LINE SHOULD BE NOTED WITH ADVANCING COLD FRONT AND GRADUAL INTENSIFICATION IS EXPECTED AS AIR MASS DESTABILIZES...PRIMARILY EAST OF THE APPALACHIANS AND WITH TIME ACROSS PORTIONS OF PA. DAMAGING WINDS MAY BE COMMON WITH THE SQUALL LINE...ESPECIALLY IF MUCAPE CAN EXCEED 1500 J/KG AS NAM SUGGESTS. AT THIS TIME WILL MAINTAIN 30% SEVERE PROBS TO ACCOUNT FOR THE EXPECTED STRONG WINDS WITH THE FRONTAL CONVECTION AND FOR ISOLATED TORNADOES THAT COULD BE NOTED IF PRE-FRONTAL DISCRETE SUPERCELLS DEVELOP. HOWEVER...THERE IS SOME CONCERN THAT A MORE WIDESPREAD EVENT MAY EVOLVE IF LOW LEVEL LAPSE RATES/INSTABILITY RESPOND PRIOR TO FRONTAL PASSAGE AND SEVERE PROBS MAY BE INCREASED TO ACCOUNT FOR THIS SCENARIO IN LATER OUTLOOKS. Link to comment Share on other sites More sharing options...
stormspotterlive Posted May 31, 2012 Share Posted May 31, 2012 For what it's worth the 12z NMM and ARW just in has storms going right to the coast tomorrow. With wind and heavy rain being the main threat here if it were to verified. http://www.meteo.psu..._12z/rloop.html Additionally the 12z euro looks to be coming in stronger for just west of the metro area. Also looks a bit more like an occluded front with how close the warm front and cold front are together. Correct me if I am wrong though. Link to comment Share on other sites More sharing options...
Thunder Road Posted May 31, 2012 Share Posted May 31, 2012 For what it's worth the 12z NMM and ARW just in has storms going right to the coast tomorrow. With wind and heavy rain being the main threat here if it were to verified. http://www.meteo.psu..._12z/rloop.html What I'm not seeing though is the discrete storms ahead of the line that you'll need if you actually want tornado potential. Now of course that could just be due to the 4 km resolution, but even the ARW has more scattered stuff (not necessarily supercells) out ahead of the main line, including one that rotates through Philly at 21z. What you see on both, however, is that the cold front is still in central PA at 0z. SPC's slight westward shift of the 15% and 30% was totally warranted, imo. Link to comment Share on other sites More sharing options...
stormspotterlive Posted May 31, 2012 Share Posted May 31, 2012 What I'm not seeing though is the discrete storms ahead of the line that you'll need if you actually want tornado potential. Now of course that could just be due to the 4 km resolution, but even the ARW has more scattered stuff (not necessarily supercells) out ahead of the main line, including one that rotates through Philly at 21z. What you see on both, however, is that the cold front is still in central PA at 0z. SPC's slight westward shift of the 15% and 30% was totally warranted, imo. I am not really seeing much of a tornado threat for us anymore either but the wind threat is defiantly holding on strong right now for most of the area. Link to comment Share on other sites More sharing options...
tombo82685 Posted May 31, 2012 Share Posted May 31, 2012 What I'm not seeing though is the discrete storms ahead of the line that you'll need if you actually want tornado potential. Now of course that could just be due to the 4 km resolution, but even the ARW has more scattered stuff (not necessarily supercells) out ahead of the main line, including one that rotates through Philly at 21z. What you see on both, however, is that the cold front is still in central PA at 0z. SPC's slight westward shift of the 15% and 30% was totally warranted, imo. yea, i like their map they drew up. Makes total sense with most the severe weather out west where the instability is. While we are on the border. Link to comment Share on other sites More sharing options...
phlwx Posted May 31, 2012 Share Posted May 31, 2012 Looked at the 12 and 18...this continues to be a MDT-LNS on south threat. Philly gets wind, some thunder, some rain...maybe severe criteria but the goods (if they go) will be in Central PA...pretty much Chambersburg to Harrisburg to Lebanon to Lancaster is the best spot in the state for anything to go. Link to comment Share on other sites More sharing options...
SmokeEater Posted May 31, 2012 Share Posted May 31, 2012 18Z 4KM Nam at 22Z on Friday suggesting some discrete cells ahead of the main line. One note: there is far less morning cloudiness from the 12Z to the 18Z runs at the same times, which could be why there are more discrete cells shown. Link to comment Share on other sites More sharing options...
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