am19psu Posted August 22, 2011 Share Posted August 22, 2011 All of the QPF guidance is showing a massive flooding event from Boston through Washington. Use this thread to discuss the general flood potential from Irene and head to the subfora for specific IMBY threats. Link to comment Share on other sites More sharing options...
Ian Posted August 23, 2011 Share Posted August 23, 2011 The 12z EURO was pretty intense with the swatch of 2"+ rains.. basically from the GA/SC border to Maine and back to western NY/PA. If it happens it could be "epic" for some given the seeming slow movement and recent heavy rains especially in parts of the urban corridor. Saving grace might be overall dry conditions from the Mid-Atl south to start? Until guidance clears up figuring out where the heaviest is/where the cutoff is/etc is a hair-pulling-out event. Link to comment Share on other sites More sharing options...
tombo82685 Posted August 23, 2011 Share Posted August 23, 2011 heres the 6hr ffg for richmond to newark Link to comment Share on other sites More sharing options...
Plowable Posted August 23, 2011 Share Posted August 23, 2011 Wonder if she has the potential or for you mets who are old enough see anything in the cards down the road to be something like Agnes back in the 70's in terms of flooring and rainfall amounts... Link to comment Share on other sites More sharing options...
Quakertown needs snow Posted August 23, 2011 Share Posted August 23, 2011 just over 6" for me this month and thats half of what many other areas around Philly are reporting. Link to comment Share on other sites More sharing options...
Ian Posted August 23, 2011 Share Posted August 23, 2011 I'm going to bribe Wes to post in this thread. Link to comment Share on other sites More sharing options...
Maximum lawman Posted August 23, 2011 Share Posted August 23, 2011 just over 6" for me this month and thats half of what many other areas around Philly are reporting. I'm at 11 and we pretty much hit flash flooding from the gitgo in yesterdays storms. I am curious if a hydrologist could discuss how quickly the guidance changes over time. For instance, if much of the northeast sees little more this week than a shower Thursday, what will that map look like on Saturday? Big changes? Link to comment Share on other sites More sharing options...
Maximum lawman Posted August 23, 2011 Share Posted August 23, 2011 I'm going to bribe Wes to post in this thread. Please do - I miss being in the mid-atlantic thread. Link to comment Share on other sites More sharing options...
usedtobe Posted August 23, 2011 Share Posted August 23, 2011 I'm going to bribe Wes to post in this thread. What about? The heavy rain that probably will occur if the storm has an inland track like the models are forecasting. Such a track usually will lead to some type of frontogenesis especially if its along the right entrance region of an upper level jet streak. That ceretainly looks like what is happening at 138 hrs. Such an alignments would be very favorable for very heavy rains if the model forecasts are correct about the storm track and interaction with the westerlies. Of course we're still dealing with a storm that is way out there in time so lots still can change. If we get closer to storm, I may write a short piece for the Capital Weater Gang if it would not be considered poaching into someone elses area of expertise. Link to comment Share on other sites More sharing options...
Ian Posted August 23, 2011 Share Posted August 23, 2011 What about? Bribe might have been the wrong word. I was trying to coax you out to post. You are the QPF master -- people should worry more about stepping on your toes talking about it. Hopefully there is reason to dust off the keyboard before winter... always a good learning opportunity. Link to comment Share on other sites More sharing options...
Srain Posted August 23, 2011 Share Posted August 23, 2011 What about? The heavy rain that probably will occur if the storm has an inland track like the models are forecasting. Such a track usually will lead to some type of frontogenesis especially if its along the right entrance region of an upper level jet streak. That ceretainly looks like what is happening at 138 hrs. Such an alignments would be very favorable for very heavy rains if the model forecasts are correct about the storm track and interaction with the westerlies. Of course we're still dealing with a storm that is way out there in time so lots still can change. If we get closer to storm, I may write a short piece for the Capital Weater Gang if it would not be considered poaching into someone elses area of expertise. So we pulled you away from that fishing after all, didn't we Wes. I look forward to your analysis. Link to comment Share on other sites More sharing options...
Huffwx Posted August 23, 2011 Share Posted August 23, 2011 Love me some WES posts-- Link to comment Share on other sites More sharing options...
ptb127 Posted August 23, 2011 Share Posted August 23, 2011 I need a quick lesson on how to read a map like this.. so this is saying that it will take 3-4" of rain to have flash flooding? What about major river flooding? heres the 6hr ffg for richmond to newark Link to comment Share on other sites More sharing options...
Kmlwx Posted August 23, 2011 Share Posted August 23, 2011 I need a quick lesson on how to read a map like this.. so this is saying that it will take 3-4" of rain to have flash flooding? What about major river flooding? 6-hour FFG means how much rain is needed in 6 hour period to cause flooding. Link to comment Share on other sites More sharing options...
battlebrick Posted August 23, 2011 Share Posted August 23, 2011 0z GFS QPF is going to be ridiculous, the thing just crawls up the whole eastern seaboard. Link to comment Share on other sites More sharing options...
LocoAko Posted August 23, 2011 Share Posted August 23, 2011 0z GFS QPF is going to be ridiculous, the thing just crawls up the whole eastern seaboard. 2-4" in western NJ with 6-7" towards the far SE NJ coast. Link to comment Share on other sites More sharing options...
BayBreeze Posted August 23, 2011 Share Posted August 23, 2011 Love me some WES posts-- all... just to make sure you recognize, the original map posted here is flash flood guidance...which is an estimate of how much rain is necessary to initiate flooding. my hunch is yhat the red areas are overdone. it has not been that dry here this summer. through the Mid Atlantic River Forecast Center, they produce these maps for 1 hr, 3 hr and 6 hour time periods. Tropical systems are well known to produce flash flooding, sometimes major, if the track of the remnants travel west of I-95 but east of the mountains and produce a strong pslope flow into the mountains. Along the eastern slopes of the Appalachains, this has produced double digit rainfall amounts which eventually makes it way into area creeks and rivers (water runs downhill). Link to comment Share on other sites More sharing options...
BayBreeze Posted August 23, 2011 Share Posted August 23, 2011 6-hour FFG means how much rain is needed in 6 hour period to cause flooding. sorry kenny. did not see this b4 i posted. so, what he said. Link to comment Share on other sites More sharing options...
BayBreeze Posted August 23, 2011 Share Posted August 23, 2011 2-4" in western NJ with 6-7" towards the far SE NJ coast. this scenario is too far east to produce major flloding in and west of the major cities. so don't model hug yet. they aint that good this far out. Link to comment Share on other sites More sharing options...
IsentropicLift Posted August 23, 2011 Share Posted August 23, 2011 12z GFS QPF through 144hrs. Major flooding verbatim Link to comment Share on other sites More sharing options...
thegreatdr Posted August 24, 2011 Share Posted August 24, 2011 That map isn't all that different than the current 5 day QPF issued this morning by HPC. Much more of a track shift to the right and Fayetteville/DC/Albany would miss out. 12z GFS QPF through 144hrs. Major flooding verbatim Link to comment Share on other sites More sharing options...
marsman Posted August 25, 2011 Share Posted August 25, 2011 For those in NC looking for floodplain maps: http://floodmaps.nc.gov/fmis/ Link to comment Share on other sites More sharing options...
A-L-E-K Posted August 25, 2011 Share Posted August 25, 2011 Looking more like every garden/basement apartment in NYC will be flooding this weekend. Link to comment Share on other sites More sharing options...
AbsolutZero Posted August 26, 2011 Share Posted August 26, 2011 Here's some images that show how much rain fell in NJ/Long Island a little better... Link to comment Share on other sites More sharing options...
wxsmwhrms Posted August 26, 2011 Share Posted August 26, 2011 Latest HPC 5-day total precipitation... Link to comment Share on other sites More sharing options...
WxUSAF Posted August 26, 2011 Share Posted August 26, 2011 Latest HPC 5-day total precipitation... They are going with a precip cutoff much farther west than what most models seem to be producing. Anyone know why? Link to comment Share on other sites More sharing options...
forkyfork Posted August 26, 2011 Share Posted August 26, 2011 i would say we are most definitely going to get a PRE http://www.hpc.ncep.noaa.gov/hmt/seminar_files/PRE_NWS_Teletraining.ppt Link to comment Share on other sites More sharing options...
WxUSAF Posted August 26, 2011 Share Posted August 26, 2011 i would say we are most definitely going to get a PRE http://www.hpc.ncep....eletraining.ppt Great stuff, Forky. I've noticed this afternoon that most models are picking up on some heavy showers coming through VA/DC/MD tomorrow morning into the afternoon. Possibly part of this phenomenon. Link to comment Share on other sites More sharing options...
usedtobe Posted August 26, 2011 Share Posted August 26, 2011 They are going with a precip cutoff much farther west than what most models seem to be producing. Anyone know why? My guess is they are leaning heavily on the Euro but don't know for sure. It verifies better than the gfs. Link to comment Share on other sites More sharing options...
canderson Posted August 26, 2011 Share Posted August 26, 2011 I'm in Harrisburg, where we had 4"+ yesterday and quite a bit earlier this week/past weekend. Any mets' thoughts on how sharp rain cutoff is to the Susquehanna Valley? If we get 5+" we're going to have serious issues. Link to comment Share on other sites More sharing options...
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