IsentropicLift Posted October 15, 2014 Share Posted October 15, 2014 As of Wednesday morning a deep trough was located over the Eastern United States with a closed 500mb low over the Ohio Valley in a classic location for a heavy precipitation event along the East Coast. Various shortwaves will rotate around the trough tonight into tomorrow morning and will deliver a threat of heavy training convection with the potential for flash flooding and perhaps some minor river or stream flooding. Catagory 4 hurricane Gonzalo was also located north of Puerto Rico as of the 11AM advisory with a minimum central pressure of 949mb. The tropical cyclone was moving NW and is forecasted to become steered by the trough exiting off the east coast on day 2 perhaps striking Bermuda as a powerful major hurricane in about 48 hours. The GFS has been showing the potential of having some of the moisture from Gonzalo becoming entrained into the trough and impacting eastern sections and New England late tommorrow. That will need to continue to be monitored. While the overall instability is low, some breaks in sun today have inscreaded SBCAPE to a few hundred J/KG and SPC has placed southern areas in a 5% risk for damaging winds and a 2% risk for tornados. Below is Uptons rainfall forecast. Generally ~ 2.00"+ closer to the city and a bit more the further east you go. Link to comment Share on other sites More sharing options...
IsentropicLift Posted October 15, 2014 Author Share Posted October 15, 2014 Link to comment Share on other sites More sharing options...
Sundog Posted October 15, 2014 Share Posted October 15, 2014 The HRRR totally kills this line of rain before it gets to NYC. Not sure if it reforms afterward because that's beyond the runtime of the model. Link to comment Share on other sites More sharing options...
Stormlover74 Posted October 15, 2014 Share Posted October 15, 2014 This must be new but the GFS now allows you to see precip in 3 hour intervals but I think 6 z and 12 z are cumulative for the 6 hour period THU 00Z 16-OCT 20.0 14.0 1012 97 94 0.21 580 569THU 03Z 16-OCT 19.9 14.2 1011 98 80 0.25 579 569THU 06Z 16-OCT 20.1 13.7 1009 97 97 0.65 577 569THU 09Z 16-OCT 20.0 13.5 1007 98 99 0.47 575 569THU 12Z 16-OCT 19.4 13.7 1007 98 80 0.64 574 568 Link to comment Share on other sites More sharing options...
IsentropicLift Posted October 15, 2014 Author Share Posted October 15, 2014 12z RGEM Link to comment Share on other sites More sharing options...
mob1 Posted October 15, 2014 Share Posted October 15, 2014 12z RGEM Is that all snow on mount Washington? Link to comment Share on other sites More sharing options...
danstorm Posted October 15, 2014 Share Posted October 15, 2014 Is that all snow on mount Washington? Not a chance in hell with this airmass. Link to comment Share on other sites More sharing options...
NycStormChaser Posted October 15, 2014 Share Posted October 15, 2014 Tornado warning for DC Link to comment Share on other sites More sharing options...
IsentropicLift Posted October 15, 2014 Author Share Posted October 15, 2014 Tornado warning for DC Was just about to post that. The 15z HRRR says that the main show doesn't move into this area until after 06z. Link to comment Share on other sites More sharing options...
cjr231 Posted October 15, 2014 Share Posted October 15, 2014 Tornado warning was cancelled pretty quickly for DC. But impressive storms nonetheless. 57mph winds reported, just near severe. Link to comment Share on other sites More sharing options...
IsentropicLift Posted October 15, 2014 Author Share Posted October 15, 2014 A station in DC just picked up 0.70" in the last ten minutes under that cell. Link to comment Share on other sites More sharing options...
Sundog Posted October 15, 2014 Share Posted October 15, 2014 The latest GGEM has a bullseye of 80mm over NYC for the 12 hour period preceding hour 24 Link to comment Share on other sites More sharing options...
IsentropicLift Posted October 15, 2014 Author Share Posted October 15, 2014 That same cell has prompted another tornado warning further NE. Link to comment Share on other sites More sharing options...
SnoSki14 Posted October 15, 2014 Share Posted October 15, 2014 The latest GGEM has a bullseye of 80mm over NYC for the 12 hour period preceding hour 24 Very possible with this system. Link to comment Share on other sites More sharing options...
Sundog Posted October 15, 2014 Share Posted October 15, 2014 Very possible with this system. Not impossible but that's over 3 inches of rain. That's definitely pushing the upper limits of potential. I'm sure someone will get bullseyed with some obscene number though. Link to comment Share on other sites More sharing options...
NycStormChaser Posted October 15, 2014 Share Posted October 15, 2014 Tornado Warning for Anne Arundel, Howard and Prince Georges Counties in MD until 1:30 PM EDT Link to comment Share on other sites More sharing options...
IsentropicLift Posted October 15, 2014 Author Share Posted October 15, 2014 The 16z HRRR has slowed down everything even more, with the heavy storms still in the Delmarva by 04z. Link to comment Share on other sites More sharing options...
Sundog Posted October 15, 2014 Share Posted October 15, 2014 The 16z HRRR has slowed down everything even more, with the heavy storms still in the Delmarva by 04z. I don't trust the HRRR outside of maybe 8 hours. Link to comment Share on other sites More sharing options...
Guest Pamela Posted October 15, 2014 Share Posted October 15, 2014 As of Wednesday morning a deep trough was located over the Eastern United States with a closed 500mb low over the Ohio Valley in a classic location for a heavy precipitation event along the East Coast. Various shortwaves will rotate around the trough tonight into tomorrow morning and will deliver a threat of heavy training convection with the potential for flash flooding and perhaps some minor river or stream flooding. Catagory 4 hurricane Gonzalo was also located north of Puerto Rico as of the 11AM advisory with a minimum central pressure of 949mb. The tropical cyclone was moving NW and is forecasted to become steered by the trough exiting off the east coast on day 2 perhaps striking Bermuda as a powerful major hurricane in about 48 hours. The GFS has been showing the potential of having some of the moisture from Gonzalo becoming entrained into the trough and impacting eastern sections and New England late tommorrow. That will need to continue to be monitored. While the overall instability is low, some breaks in sun today have inscreaded SBCAPE to a few hundred J/KG and SPC has placed southern areas in a 5% risk for damaging winds and a 2% risk for tornados. Below is Uptons rainfall forecast. Generally ~ 2.00"+ closer to the city and a bit more the further east you go. NWS attempt to forecast and differentiate among the various local stations concerning rain amounts to the hundredth of an inch is lol worthy. Link to comment Share on other sites More sharing options...
REDMK6GLI Posted October 15, 2014 Share Posted October 15, 2014 NWS attempt to forecast and differentiate among the various local stations concerning rain amounts to the hundredth of an inch is lol worthy. They're trying to raise the bar for accuracy cant you see that??? Link to comment Share on other sites More sharing options...
Sundog Posted October 15, 2014 Share Posted October 15, 2014 12z Euro still not as impressed with barely an inch in general for most people in the tristate. Link to comment Share on other sites More sharing options...
IsentropicLift Posted October 15, 2014 Author Share Posted October 15, 2014 12z Euro still not as impressed with barely an inch in general for most people in the tristate. It has 2-2.50" for Eastern PA and that matches up well with current radar. Link to comment Share on other sites More sharing options...
ag3 Posted October 15, 2014 Share Posted October 15, 2014 12z Euro still not as impressed with barely an inch in general for most people in the tristate. It got a lot wetter overall though. Link to comment Share on other sites More sharing options...
IsentropicLift Posted October 15, 2014 Author Share Posted October 15, 2014 Why are people still worried about QPF? A station in northeast DC today picked up 0.97" from 12:38PM-1:03PM. PWAT's are running 250-300% above normal. Link to comment Share on other sites More sharing options...
danstorm Posted October 15, 2014 Share Posted October 15, 2014 It has 2-2.50" for Eastern PA and that matches up well with current radar. Well now, are you actually putting stock in the driest model? Link to comment Share on other sites More sharing options...
NEG NAO Posted October 15, 2014 Share Posted October 15, 2014 IMO this will very soon become a nowcasting event - part of the problem with previous storm threads was not paying attention to what was going on real time on radar and assuming somehow certain models would end up verifying which they did not.......... Link to comment Share on other sites More sharing options...
IsentropicLift Posted October 15, 2014 Author Share Posted October 15, 2014 Well now, are you actually putting stock in the driest model? Models have been hinting for days that we would see two precip maxes, one in eastern PA and the other over Long Island. Most people in this sub-forum will be relying on the shortwave coming through around 06z for our heaviest rains. Link to comment Share on other sites More sharing options...
REDMK6GLI Posted October 15, 2014 Share Posted October 15, 2014 IMO this will very soon become a nowcasting event - part of the problem with previous storm threads was not paying attention to what was going on real time on radar and assuming somehow certain models would end up verifying which they did not.......... I agree with this statement. Even our short range Hi-Res models have trouble picking up little nuances that can change the outcome of a storm. Nowcasting is a pretty good move at this point. I do agree with yanksfan in the two precip maxes being E.PA and LI but i would shift the LI max to include NYC unless he actually inferred that as well Link to comment Share on other sites More sharing options...
IsentropicLift Posted October 15, 2014 Author Share Posted October 15, 2014 The 21z SREF mean has the bullseye over the next 24 hours in the same spot as the 12z ECMWF. The latest HRRR holds the line together a bit better for northern NJ and some places could be well over an inch before the main event moves through after 06z. Link to comment Share on other sites More sharing options...
TonyLovesSnow Posted October 15, 2014 Share Posted October 15, 2014 I agree with yanks about bullseye being in Long Island and eastern Pa. Although I think I would include NYC in that to get at least 1.25-2.00 inches. Especially if that frontal boundary takes it's time like it is right now on the eastern PA. Btw I think accuweather stole my winter forecast take a look... I mean they literally have the same map as me. How rude! http://m.accuweather.com/en/weather-news/us-2014-2015-winter-forecast/35422753 Oh well. Enjoy ur afternoon folks Link to comment Share on other sites More sharing options...
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