NortheastPAWx Posted February 25, 2011 Share Posted February 25, 2011 I think this event has the better chance of seeing widespread flooding. Looks like another shot of 1.00+ QPF across the area. In addition, I see H85 temps spiking over +10C area wide, which will basically melt off any snow remaining. With snowmelt (Especially upstream on some rivers) and the saturated ground, flooding looks like a big threat to me. Link to comment Share on other sites More sharing options...
tombo82685 Posted February 25, 2011 Share Posted February 25, 2011 12z euro is going 1-2 inches for the area from i95 north. Link to comment Share on other sites More sharing options...
ParanormalWx Posted February 26, 2011 Share Posted February 26, 2011 I would throw in a severe threat to this throughout the CWA as temps and dewpoints torch. Link to comment Share on other sites More sharing options...
phlwx Posted February 26, 2011 Share Posted February 26, 2011 I would throw in a severe threat to this throughout the CWA as temps and dewpoints torch. Yeah, wouldn't surprise me. I was going to say with timing on the frontal passage being after dinner that I wouldn't be surprised if Philly made a run at 70 on Monday if there is decent amounts of sun around midday. 850's on the Euro are +12 up to Philly. Link to comment Share on other sites More sharing options...
tombo82685 Posted February 26, 2011 Share Posted February 26, 2011 Yeah, wouldn't surprise me. I was going to say with timing on the frontal passage being after dinner that I wouldn't be surprised if Philly made a run at 70 on Monday if there is decent amounts of sun around midday. 850's on the Euro are +12 up to Philly. Link to comment Share on other sites More sharing options...
tombo82685 Posted February 26, 2011 Share Posted February 26, 2011 euro is going another .75-1.5 for the region on monday into tuesday. Link to comment Share on other sites More sharing options...
atownwxwatcher Posted February 27, 2011 Share Posted February 27, 2011 00z NAM Link to comment Share on other sites More sharing options...
Thunder Road Posted February 27, 2011 Share Posted February 27, 2011 KPHL sees 3.06" per 0z NAM Link to comment Share on other sites More sharing options...
Thunder Road Posted February 27, 2011 Share Posted February 27, 2011 It looks like we get flooding or strong storms, but not both. It appears to me that the NAM strings the storm out, and gives us heavy rain (perhaps convective) but no real line of storms, whereas the GFS is faster and has a more organized storm line since the main storm is also more consolidated and farther north. In a situation like this, I would have to assume the GFS QPF is overdone given the mesoscale convective nature of the storm, but I would have to assume as well that the NAM is overdone because it's the NAM and it's always overdone. That said, 3" of rain with the ground as soggy as it is would be very bad Link to comment Share on other sites More sharing options...
Thunder Road Posted February 27, 2011 Share Posted February 27, 2011 Perhaps the NAM placing a second low along the "line" is just error because it's trying to turn convection into a discrete SLP like it does with our coastal storm when they're developing in Gulf. curious to see what the hi-res models have tonight for the first part. The NAM hits us with over 0.50" of front-end precip, whereas the GFS has less than 0.25" at the same time Link to comment Share on other sites More sharing options...
Thunder Road Posted February 27, 2011 Share Posted February 27, 2011 New SPC outlooks have a SLIGHT risk all the way up to Williamsport-Scranton-NYC: Link to comment Share on other sites More sharing options...
Thunder Road Posted February 27, 2011 Share Posted February 27, 2011 hi-res NAM holds serve, perhaps a little bit wetter but in a more narrow corridor. Sim radars are almost identical. of course the ARW is completely different, only 0.75-1.00 total for the event... Link to comment Share on other sites More sharing options...
phlwx Posted February 27, 2011 Share Posted February 27, 2011 I don't like the bagginess of this storm system on the models...would like to see a stronger primary low and more negative tilting on the 500 mb level for me to really get amped up for severe with this system. The wind shear potential is pretty decent and there's a good bit of wind energy (50 kt + at 850 per the NAM). The wind potential is about the best thing going for this system... If anything pops, it's probably S Central PA, MD on south then marching east towards Philly...seems like that's where the warmth will reside... Definite heavy rain threat though...hating that the 6z GFS and 6z NAM were identical on the heaviest rains being just north of the Turnpike...3" on the NAM *yikes* Link to comment Share on other sites More sharing options...
LMolineuxLM1 Posted February 27, 2011 Share Posted February 27, 2011 I don't like the bagginess of this storm system on the models...would like to see a stronger primary low and more negative tilting on the 500 mb level for me to really get amped up for severe with this system. The wind shear potential is pretty decent and there's a good bit of wind energy (50 kt + at 850 per the NAM). The wind potential is about the best thing going for this system... If anything pops, it's probably S Central PA, MD on south then marching east towards Philly...seems like that's where the warmth will reside... Definite heavy rain threat though...hating that the 6z GFS and 6z NAM were identical on the heaviest rains being just north of the Turnpike...3" on the NAM *yikes* Now your speaking words that I like. If anything Pops it will march east towards Philly, I can dig that. Allse I say is bring it on. Could be a making up for last years thunderstorm screw overs. Link to comment Share on other sites More sharing options...
Thunder Road Posted February 27, 2011 Share Posted February 27, 2011 12z NAM data is very interesting. It gives PHL just 0.40" for the entire storm, but DYL gets 2.00"! PNE falls right in the middle at 1.03". 12z NAM was also much warmer, 850 temps surge to +12.7 at 18z Mon., which translates to 63.5°F at the surface at 21z at PHL. It looks like a line of thunderstorms will set up somewhere and train over the same area. The NMM last night was indicating something similar. Link to comment Share on other sites More sharing options...
chubbs Posted February 27, 2011 Share Posted February 27, 2011 Not a bad severe set-up for this area and time or year. Marginal instability with forcing and strong winds above surface. Time of day is good also. Link to comment Share on other sites More sharing options...
phlwx Posted February 27, 2011 Share Posted February 27, 2011 12z NAM data is very interesting. It gives PHL just 0.40" for the entire storm, but DYL gets 2.00"! PNE falls right in the middle at 1.03". 12z NAM was also much warmer, 850 temps surge to +12.7 at 18z Mon., which translates to 63.5°F at the surface at 21z at PHL. It looks like a line of thunderstorms will set up somewhere and train over the same area. The NMM last night was indicating something similar. Record tomorrow is 68 @ PHL. If we get more than a couple of breaks in the clouds we probably approach 70...mid 60's is probably a good bet though... Link to comment Share on other sites More sharing options...
IsentropicLift Posted February 27, 2011 Share Posted February 27, 2011 I'm a tad suprised the flood watches are not more widesread at the moment. HPC currently calling for 1.00"+ QPF which I think is underdone and even with that amount all of the latest river forecasts either fall just short of caution or reach caution stage. Link to comment Share on other sites More sharing options...
dssbss Posted February 27, 2011 Share Posted February 27, 2011 NJZ001-PAZ054-055-281100- /O.NEW.KPHI.ZR.Y.0003.110228T0700Z-110228T1300Z/ SUSSEX-CARBON-MONROE- INCLUDING THE CITIES OF...NEWTON...JIM THORPE...STROUDSBURG 328 PM EST SUN FEB 27 2011 ...FREEZING RAIN ADVISORY IN EFFECT FROM 2 AM TO 8 AM EST MONDAY... THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY HAS ISSUED A FREEZING RAIN ADVISORY...WHICH IS IN EFFECT FROM 2 AM TO 8 AM EST MONDAY. * LOCATIONS...MONROE AND CARBON COUNTIES IN EASTERN PENNSYLVANIA AND SUSSEX COUNTY IN NORTHWEST NEW JERSEY. * HAZARD TYPES...FREEZING RAIN * ACCUMULATIONS...ICE ACCUMULATION SHOULD AVERAGE LESS THAN 0.05 INCHES. * TIMING...LIGHT FREEZING RAIN IS EXPECTED IN THE HIGHER ELEVATIONS AFTER 200 AM. LIGHT FREEZING RAIN COULD LINGER IN THE NORMALLY COLDER LOCATIONS UNTIL THE BEGINNING OF THE MORNING COMMUTE. * IMPACTS...UNTREATED ROADS...SIDEWALKS AND PARKING LOTS MAY BE COATED WITH A THIN LAYER OF ICE. IT ONLY TAKES A SMALL AMOUNT OF ICE TO MAKE WALKING AND DRIVING SURFACES SLIPPERY. * WINDS...EAST 5 TO 10 MPH. * TEMPERATURES...IN THE LOWER 30S. Link to comment Share on other sites More sharing options...
tombo82685 Posted February 27, 2011 Share Posted February 27, 2011 18z nam popping phl in the low 70s tomorrow. Link to comment Share on other sites More sharing options...
phlwx Posted February 27, 2011 Share Posted February 27, 2011 18z nam popping phl in the low 70s tomorrow. Just saw that...bring it. Also bullish on severe in the late afternoon...some pretty nasty storms pop on it. Link to comment Share on other sites More sharing options...
NortheastPAWx Posted February 27, 2011 Author Share Posted February 27, 2011 NAM even tries to bring the 60s into NEPA. Link to comment Share on other sites More sharing options...
atownwxwatcher Posted February 28, 2011 Share Posted February 28, 2011 HPC actually cuts back on the rainfall...50-.75 now Link to comment Share on other sites More sharing options...
IsentropicLift Posted February 28, 2011 Share Posted February 28, 2011 It follows the 00z NAM fairly well in terms of where the heaviest QPF will occur although I think the QPF will be higher than forecasted over north Jersey. Link to comment Share on other sites More sharing options...
Thunder Road Posted February 28, 2011 Share Posted February 28, 2011 What I'm a bit perplexed by is that the line of storm tomorrow doesn't drop north-south. It more or less sets up over one area and then just trains over that area. So most people see less than 0.50", while some areas see 2.00"-3.00" and major flash flooding. Pinpointing where exactly that ends up is a nightmare, as I've seen it modeled in various placed between Allentown and Cape May over the past few days. I think many will end up feeling shafted tomorrow because they are looking at the smoothed-over globals that are giving everyone 1.00" or more Link to comment Share on other sites More sharing options...
Grothar Posted February 28, 2011 Share Posted February 28, 2011 HPC actually cuts back on the rainfall...50-.75 now Current radar observations in the Ohio Valley indicate that we are going to get our butt kicked in warm frontal training thunderstorms with the real potential for very heavy rainfall in the morning hours I see the the warm front going through and skies clearing in the early afternoon to fuel a squall line through our area in the early evening. I am more worried about the warm frontal rains flooding our area with 2 or more inches of rain on saturated soils than the flash flooding rains from the cold front. Link to comment Share on other sites More sharing options...
Quakertown needs snow Posted February 28, 2011 Share Posted February 28, 2011 heavy hitters Link to comment Share on other sites More sharing options...
NaoPos Posted February 28, 2011 Share Posted February 28, 2011 here's the 0z NAM 36hr total.. Link to comment Share on other sites More sharing options...
atownwxwatcher Posted February 28, 2011 Share Posted February 28, 2011 00z GFS total Link to comment Share on other sites More sharing options...
Thunder Road Posted February 28, 2011 Share Posted February 28, 2011 0z NAM gets PHL's 850's to 13.1 C at 18z. Can we say 70s anyone? Hopefully that's more thunderstorm fuel, but we'll see. Link to comment Share on other sites More sharing options...
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