Jump to content
  • Member Statistics

    17,502
    Total Members
    7,904
    Most Online
    Weathernoob335
    Newest Member
    Weathernoob335
    Joined

Few clusters max rfall 2-3" and possible SVR Mon-Tue 8/24-25/20


wdrag
 Share

Recommended Posts

Monday-Tuesday: Issued a low confidence topic for more widespread heavy thunderstorms with potential for 2-3" max rainfalls (this was modeled for Sunday several days ago by the EC-but delayed for most of our area-except Ocean County- til Monday).  KI is up, actually quite high for Monday morning so we may get a quick start Monday.  PW up to near 1.8". 

Cannot rule out an isolated SVR Monday afternoon but the two day topic includes Tuesday's SPC slight risk.  SPC sees more detailed model information than I, so despite my concerns about general nw 850MB flow which tends to be negative for convection holding together east of Appalachians,  I've included Tuesday per SPC yesterdays D4 and todays D3.  I could see best chance SVR early in the day but this hopefully will be improved as we draw closer.  Plenty of wind in the sounding and enough CAPE/KI for sure, but don't quite like the 850 flow.  858A/23

  • Like 3
  • Thanks 2
Link to comment
Share on other sites

On todays rain...  finally... and not quite done.  Jackson Township NJ in northern Ocean County near I195...training and repeat episodes... have reposted 1.5 to 2.5" as in this attached weather underground report... 2 times as much as the digital radar estimate.  Don't be fooled the next few days. Some gully washers coming this week, I think. 711P/23

Screen Shot 2020-08-23 at 7.07.00 PM.png

  • Like 2
Link to comment
Share on other sites

Good Monday morning!  

I woke up to storm modeling thats seems too quiet for this afternoon... cells few and far between.  I'll stay with the HRDPS and EC, inclusive of mid-upper 30s KI axis ne PA-SE NYS-CT into extreme nw NJ at 18z. That should allow clusters of strong storms to develop ne PA and se NYS between 1-3PM and track east southeast into CT, northern NJ n of I78 onto LI during the remainder of the afternoon and die out around 8 or 9 PM.  So we saw what yesterday brought to near Lakewood NJ. I suspect the same along or north of I80.  Not impossible to have isolated SVR but not expecting FF 4" production.  PWAT will be near 1.7-1.8. CAPE up near 2000J but not much wind aloft. I did see the HRRR is spitting out a bit of hail in e PA and se NYS. 

Tuesday: Please read SPC D2 and NWS local office discussions as well your own.  Today, it looks little more favorable to me for SVR cells drilling southeastward across our area between 2P and 9P with the 850 flow turning a little more westerly ahead of the cool front permitting less downsloping. CAPE, KI, WIND aloft all look favorable.  In addition to the the damaging wind/hail potential, despite the faster southeast movement of the cells,  should see 2-3" in an hour beneath a couple of the tracks of of the strongest cells.  Most favored region is is probably se NYS/ne PA, NJ to near NYC.. 627A/24

  • Like 1
Link to comment
Share on other sites

This afternoon-evening: Does not look at all promising for much, as of this 40PM writing for our area, but still a chance of development. Cells appear too small, and too slow moving but maybe outflows will coalesce activity between 4 and 7PM? in CT/NJ?  Seems like run of the mill so far. 

Tomorrow: am not convinced of much, but if there will be strong action, think its mostly NJ and e PA, especially where SPC has their enhanced risk now Pls see attached). Again, I'm uneasy because of the generally nw flow and a bit of a lack of surface convergence. Am getting a sense a line will be crossing NJ between 9A and 2PM, with not much left later on  during peak heating.  Just doesn't seem well meshed but staying with SPC as they write with more enthusiasm for something pretty good, mostly sw portion of the forum. 

Screen Shot 2020-08-24 at 2.24.58 PM.png

  • Like 2
  • Thanks 1
Link to comment
Share on other sites

Good Tuesday morning everyone,  

Yesterday's radar is attached. pinged a 2-3" per OKX radar and Digital storm total Fairfield County CT, with SVR just east of the forum in Portland CT and as posted above in ne PA with a few 1" wxunderground reports into nw NJ and sw CT. The big stuff was mostly ne PA and se CT... and not a good forecast for our area. The modeling hesitancy was useful in toning down expectations. I may add a CoCoRAHS mapping by midday.

Today, as posted just above this, per SPC.  My concerns are #1... leftover dying convective debris this morning limiting redevelopment potential for most of our forum this afternoon, and just the general lack of convergent flow.  Some modeling diminishes the activity as it approaches aopur area while HRDPS is very interested in an active afternoon.  I'm with less than ideal confidence, but leave it to local NWS and SPC discussions.  The topic is here and hopefully w some reports of svr later this morning or afternoon. 

 

Screen Shot 2020-08-24 at 9.07.48 PM.png

Link to comment
Share on other sites

16z=Noon  developing line of act-broken showers moving steadily se near I90 NYS.  Bothered that the GFS looses this convection se of the Catskills, whereas the HRRR looses some but it hasn't got a good handle on 16z. HRDPS keeps driving convection seed this afternoon.  Please see 1302z SPC D1 update on wording caution regarding coverage.  

Finally have only seen 12z SPC HREF through 17z, but it seems to have a good handle on the midday activity.  Will be curious as to how it evolves this afternoon  via the modeling.  Need to be a little cautious about a decent outbreak despite potency -  remember this is mainly wnw-nw flow at 850MB, not a favorable direction of lift, once past the Catskills. 1205P/25

Link to comment
Share on other sites

Have just added the 12z/25 SPC HREF MEAN QPF for our area, ending 12z Wednesday, basically exiting the southern part of our forum area around 7PM this evening.  This is actually somewhat optimistic for svr event potential in NJ. The max rainfall in a couple of spots with fast movers, probably no more than 2" and likely 1" or less (speed and not expecting training). 

One other note: saw the 16z surface map and we need more of a west or event wsw surface wind ahead of this line.  Lack of convergence may nix the opportunity for storms, especially CT. Need to see more backing...AVP was fine and southern LI fine but the rest... not what I want to see. My wind is also nw... not good news.

So there is opportunity, especially NJ e PA but it's not a strong likelihood til maybe down near PHL.  Again, only opinion on pattern recognition. 

Screen Shot 2020-08-25 at 12.09.33 PM.png

Link to comment
Share on other sites

1252P...wind backing here in Wantage to sw and that's a good sign. Also small cells in ne PA... might it be that the line moving south of central NYS gives it up soon for a PA only broken line of convection with sct svr?  I like the wind backing a bit in PA, even CT but more so PA.  Lot's of uncertainty. 

Link to comment
Share on other sites

Unless anyone else see it different, it appears to me the SPC HREF and HRDPS have the best handle on 18z convection...slightly different impacts here (HREF w of NYC, 12z RDPS NYC east. 16z HRRR seems to be struggling but it also might be onto something.  We'll know more by 245P. 

  • Like 1
Link to comment
Share on other sites

 Severe Thunderstorm Watch Number 450
   NWS Storm Prediction Center Norman OK
   310 PM EDT Tue Aug 25 2020

   The NWS Storm Prediction Center has issued a

   * Severe Thunderstorm Watch for portions of 
     Connecticut
     Massachusetts
     Eastern Maine
     Southern New Hampshire
     Northeast New Jersey
     Southeast New York
     Rhode Island
     Southern Vermont
     Coastal Waters

   * Effective this Tuesday afternoon and evening from 310 PM until
     1000 PM EDT.

   * Primary threats include...
     Scattered damaging wind gusts to 70 mph possible
     Isolated large hail events to 1.5 inches in diameter possible

   SUMMARY...Clusters of severe thunderstorms will move southeast
   across the watch area through early evening with a risk for damaging
   wind gusts and isolated instances of large hail.

   The severe thunderstorm watch area is approximately along and 60
   statute miles east and west of a line from 25 miles east northeast
   of Augusta ME to 10 miles southwest of Bridgeport CT. For a complete
   depiction of the watch see the associated watch outline update
   (WOUS64 KWNS WOU0).
Link to comment
Share on other sites

Just now, wdrag said:

Just seems marginal to me so far. Has to happen by 545 in NYC of anything substantial

imo the best way to get good coverage later would be to have the cells currently in ne nj lay down a boundary which serves as a guide for the storms in central ny/pa

  • Like 1
Link to comment
Share on other sites

My last for a little while I think.  Modeling is maybe an hr fast... HRRR still looks too dry but a consideration.  12z RDPS and SPC HREF appear best to me and certainly the GFS is not doing well after 18z. Still a little worried about all the w-nw low lvl flow and lack of well defined sfc convergence.  419P.

Link to comment
Share on other sites

21 minutes ago, Cfa said:

Though being in Long Island requires one to have the lowest expectations in the region, I really appreciate these discussions/threads.

Cell exiting The Bronx is heading my way, we’ll see what happens with that.

Came through here, very brief burst of heavy rain and it was gone, no wind.

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...