Jump to content
  • Member Statistics

    17,128
    Total Members
    7,904
    Most Online
    Jdhuffmanhws
    Newest Member
    Jdhuffmanhws
    Joined

Possible few SVR/FF Sat July 11 Noon-11P


wdrag
 Share

Recommended Posts

Please see SPC, NWS discussions, any statements, and our own members. Leftover PWAT, relatively strong 500MB (30kt) wind field, modeled CAPE, lightning density, SPC HREF and WPC D1 QPF all  suggest pretty decent convection this afternoon dying out by late evening.  Combination of convection (expecting several 1.5 to as much as 3" amounts today) and past weeks rains, should more easily permit isolated flash flood. Wind damage, mostly associated with wind and maybe a couple of uproots because of somewhat softer ground. Hail not mentioned but I dont think primary in this leftover tropical environment. Eastern LI seems less likely for SVR/FF this event.  

  • Like 1
Link to comment
Share on other sites

You all saw this?


 
Mesoscale Precipitation Discussion: #0470 
(Issued at 205 PM EDT Sat Jul 11 2020 ) 
 
MPD Selection
 


Graphic for MPD #0470
Mesoscale Precipitation Discussion 0470...Corrected
NWS Weather Prediction Center College Park MD
205 PM EDT Sat Jul 11 2020

Corrected for end time and removing counties from image

Areas affected...Eastern PA, Northern NJ, Southeast Upstate NY and
NYC

Concerning...Heavy rainfall...Flash flooding possible

Valid 111800Z - 120000Z

Summary...Showers and thunderstorms developing in a highly
unstable environment will become more widespread through the
afternoon. Rainfall rates will likely exceed 1"/hr, and may
approach 2"/hr at times. Despite rapid storm motion, rainfall of
1-2" with isolated higher amounts is possible. This rain falling
on top of saturated soils may produce flash flooding.

Discussion...Showers and thunderstorms evident in reflectivity
from KDIX WSR-88D are expanding in coverage this afternoon. This
expansion is due to intensifying ascent in an increasingly
favorable thermodynamic environment. GOES-16 WV imagery indicated
a shortwave lifting northward from southern NJ, impinging upon a
stationary front analyzed at 15Z extending from a surface low in
NW Upstate New York southward to the Chesapeake Bay. Recent GPS
observations measured TPW of 1.9-2.1 inches, around 1.5 standard
deviations above the climo mean, while RAP analyzed MUCape had
climbed to around 2000 J/kg east of the stationary front.

As the afternoon progresses, ascent will expand into the moist and
unstable environment as the shortwave and front lift
east-northeast. This should lead to increasing areal coverage of
thunderstorms. With PWs remaining around 2" and MUCape potentially
approaching 3000 J/kg, rain rates of more than 1"/hr are likely as
noted by high HREF neighborhood probabilities. The limiting factor
to flash flooding will be the expected rapid storm motions to the
NE as noted by 25-30 kts of 850-300mb mean flow. However, bulk
shear of 25 kts and unidirectional shear parallel to the
stationary front both pose a threat for some storm organization
and short-term training. This suggests that despite the rapid cell
motion, rain rates of 1-2"/hr occurring multiple times across the
region could produce 1-2" of rainfall with isolated higher
amounts, and this is reflected by CAMs simulated reflectivity and
6-hr QPF.

FFG here is quite low due to saturated soils from recently
departed T.S. Fay. Rainfall of 2-5" occurred Friday, producing
compromised FFG that is as low as 0.25"/1hr, with widespread FFG
less than 1"/1hr and 1.5"/3hrs. HREF 3-hrly exceedance
probabilities climb to near 50%, and NWM streamflow anomalies show
several areas of high flow. While flash flooding is not expected
to be widespread, these excessive rates, especially if they occur
in any urban areas or across the most sensitive FFG, could lead to
flash flooding into this evening.

Weiss

 

  • Like 1
Link to comment
Share on other sites

3 minutes ago, Will - Rutgers said:

Impressive cell over me in Piscataway, might've gusted to 50 at one point.  The rain is heavier now than probably any point yesterday.  Ponding all over the place, we might be at 0.75"?  Few CTC rumblers too.

Not too bad here. Heaviest went to my north and south 

Link to comment
Share on other sites

Well...this one is about over.  Not a good day for warnable storms.  many brief heavy sun showers w rainbows, isolated thunderstorms. Few below severe gusts. Wantage .24" around 545P w a gust 27MPH. A few power outages se NYS. Did not quite live up to marginal risk here in NY forum.  

Link to comment
Share on other sites

2 hours ago, Will - Rutgers said:

Impressive cell over me in Piscataway, might've gusted to 50 at one point.  The rain is heavier now than probably any point yesterday.  Ponding all over the place, we might be at 0.75"?  Few CTC rumblers too.

The heaviest part of that cell went a few miles to my south, but we still had a pretty heavy downpour and gusty winds (30 to 35mph). I got 0.44" from it. And another tiny cell came through a little while ago and dropped a quick 0.10". Really glad we finally broke our drought here in Piscataway! Over a half inch today and three quarters of an inch from a t-storm a few days ago, and of course the big 2 and half inches of rain from the tropical storm yesterday. Won't have to water for quite awhile.

  • Like 3
Link to comment
Share on other sites

Unsure what will be reported from the recent warning in se NYS...but thought it would be interesting to post OKX radar, a couple of wundermaps with large 2+ amounts (includes a slight amount of early this morning), verifying OKX radar (yellows 2+") and radarscope digital storm total and verifying the SPC HREF max qpf fcst for today (12z/10, 00z/11, 12z/11-you will see the init times I have reversed order but the idea is there just the same))  Note ne NJ and se NYS, and subsequent verification idea (purple is 1.5+ and red is 3+). This is why WPC and myself use this guidance quite a bit. 845P/11

Screen Shot 2020-07-11 at 8.30.26 PM.png

Screen Shot 2020-07-11 at 8.33.53 PM.png

Screen Shot 2020-07-11 at 8.35.56 PM.png

Screen_Shot_2020-07-11_at_8_24.47_PM.png

Screen_Shot_2020-07-11_at_8_25.13_PM.png

Screen_Shot_2020-07-11_at_8_25.46_PM.png

  • Thanks 1
Link to comment
Share on other sites

7 hours ago, gravitylover said:

That last round of storms came through in a rather dramatic fashion and dropped an inch in a pretty short time. The wind was worse than yesterday, the rain was much heavier and w lost some big tree branches in addition to more garden damage.  Uggh

These reports, akin to this, not sure if they're called into the NWS or sent in on a spotter line.  This kind of documentation is valuable for NWS (and ourselves) self assessment. I can help get this connected to the right location for their consideration. Good report. Thanks. 

  • Thanks 1
Link to comment
Share on other sites

13 hours ago, wdrag said:

These reports, akin to this, not sure if they're called into the NWS or sent in on a spotter line.  This kind of documentation is valuable for NWS (and ourselves) self assessment. I can help get this connected to the right location for their consideration. Good report. Thanks. 

I've never called a report in. Since the turn of the century I've hoped that those that need to know follow the forums and the reports we post are seen and utilized. Is that too optimistic? 

Link to comment
Share on other sites

Too optimistic... office's can be tied up in forecast processes, resolving communications difficulties, be it radar, computers etc, answering media, following twitter, messenger, automated data platforms (of which there are many). Now with COVID, not sure how many are in the office to assist (teleworking?).  

Here's a link which i didn't try, but presume works.  You may want to include in the narrative your equipment, exposures for wind...if time and if you feel necessary.  I liked to see credible data and sometimes NWS has to initially filter out data that at first glance looks suspect.  Any problems, please let me know.  Thanks for checking back on this.  I recommend this for everyone. Just use the criteria that they give you (pasted below the link - used PHI since it's slightly more compact-note the SVR reports that SPC posts. A large branch can count.

https://www.weather.gov/okx/SubmitStormReport

Submit Storm Report

 

Submit a Report!

Send a Storm Report to NWS Mount Holly Privacy Policy
Users can send storm reports via email to the following email address: Please provide the following information:
  • Name and/or Skywarn ID
  • Phone number
  • City, county, and state
  • Latitude and longitude (if known)
  • Date and time of the weather event
  • Type and description of weather observed (see the table below)
  • Photographs of measurement and/or damage, if possible
 
The National Weather Service in Mount Holly NJ greatly appreciates the cooperation
and dedication of all of our spotters and cooperative weather observers.

Tornadoes

Flooding

Winter Weather

  • Tornado
  • Funnel cloud
  • Wall cloud
  • Persistent rotation
  • Flooding that results in evacuations
  • Water rescues: cars, roofs, or trees
  • Water rapidly rising, or entering homes, not just basements
  • Roads impassable or closed due to high water
  • Small streams or rivers overflowing their banks
  • Moderate coastal flooding, not just nuisance inundation
  • 1”+ snow in 24 hours
  • 1”+ snow in past hour
  • Freezing rain/drizzle
  • Any ice accumulation

Thunderstorms

Miscellaneous

  • Tree uprooted or downed
  • > 1 large limb downed
  • Power lines downed
  • Hail (any size)
  • Rain > 1” in past hour
  • Winds > 40 MPH
  • Damage to structures
  • Tsunami

Any injuries or deaths that are weather related

 

  • Thanks 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...