Jump to content
  • Member Statistics

    17,598
    Total Members
    7,904
    Most Online
    PublicWorks143
    Newest Member
    PublicWorks143
    Joined

Sun July 11-Mon July 19 Pockets of FF/SVR and a modest heat wave


wdrag
 Share

Recommended Posts

1 hour ago, SRRTA22 said:

What do you want them to do, issue a FFW for one or two counties? 

The ffw is warranted. Some places will miss and some places may flood. 

I would keep the flash flood watch to the western half of the city and west, although I guess to be safe they included Nassau County. Models seem to be killing anything east of the city right away in the seabreeze. Hopefully we can get a reprieve from the humidity ASAP, that's what I'm hoping for. I'll be surprised if anything more than a moderate shower makes it out past here. 

  • Like 1
  • Weenie 1
Link to comment
Share on other sites

32 minutes ago, LoboLeader1 said:

E6b0vPtX0AA6T_w?format=jpg&name=900x900

And the discussion with the map below.  We’ll see what they have in the next update.

SPC AC 161728

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1228 PM CDT Fri Jul 16 2021

   Valid 171200Z - 181200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE NORTHEAST/MID-ATLANTIC AND THE NORTHERN/CENTRAL PLAINS...

   ...SUMMARY...
   Isolated strong to severe storms will be possible across portions of
   the Northeast/Mid-Atlantic and northern/central Plains on Saturday.

   ...Northeast/Mid-Atlantic...
   A belt of modestly enhanced mid-level southwesterly flow should be
   maintained Saturday across much of the Northeast and Mid-Atlantic
   ahead of a positively tilted upper trough. At the surface, a weak
   low is forecast to develop from the lower Great Lakes across NY and
   into southern New England by Saturday evening. A cold front should
   extend southwestward from this surface low across the Mid-Atlantic
   and into the central Appalachians, while a weak warm front extends
   across southern NY and southern New England. Current expectations
   are for multiple clusters of storms to develop along/ahead of the
   cold front and a pre-frontal trough through the day, and
   subsequently move eastward across the warm sector. Low/mid-level
   flow should not be overly strong, but generally 20-30 kt of
   deep-layer shear should be sufficient for modest updraft
   organization and mainly a multicell/cluster storm mode. Daytime
   heating of the moist low-level airmass ahead of these storms will
   likely foster steepened low-level lapse rates and moderate to strong
   instability, particularly across the Mid-Atlantic east of the
   Appalachian and Blue Ridge Mountains. Isolated damaging wind gusts
   should be the main threat. Both low-level and deep-layer shear may
   be slightly stronger across southern NY/New England, and marginal
   supercells posing both an damaging wind and brief tornado threat
   appear possible, particularly in the vicinity of the weak warm
   front.

Upton's AFD,

Area Forecast Discussion National Weather Service New York NY 1104 PM EDT Fri Jul 16 2021 .SYNOPSIS... A slow moving frontal boundary will stall across the area tonight, then lift northward as a warm front on Saturday. A separate weak cold front will then slowly approach from the west Saturday night, move across on Sunday, and pass slowly east on Monday. Another weak frontal boundary will approach on Wednesday. Weak high pressure will then build in for Thursday and Friday. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Frontal boundary remains across the area overnight. As a result, light and variable winds and high humidity will keep low temperatures in the upper 60s to mid 70s. Expect fog to develop again across eastern Connecticut and Long Island, perhaps even more widespread compared to previous nights as winds decrease and/or go calm in the vicinity of the frontal boundary. The 00Z NamNest shows an area of convection blossoming across south central PA and working NE into the area during the early morning hours. Latest HRRR, FV3, ARW, don`t support this scenario. However, latest regional radar does show development in this area, even ahead of the NamNest timing. There is little if any upper forcing with the main lift being provided by the surface boundary. So, have my doubts to the longevity of this convection. Simply put, it will have to watched and chances may need to be increased should this area continue to hold together the next several hours. Regardless, the potential exists for at least isolated showers/thunderstorms overnight. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... A flash flood watch remains in effect for portions of the area for Saturday afternoon and night. As high pressure shifts offshore and a frontal wave approaches from the west, moisture advection will allow PWAT values to increase to above 2 inches. Despite a general forward motion of the storms around 20-30 kt, heavy rainfall combined with antecedent wet conditions due to previous rainfall will lead to an increased threat of flash flooding across the areas within the watch. The period of greatest potential will be from roughly 8 pm into the overnight. Additionally, storms will be capable of gusty winds and perhaps brief rotation, especially in the vicinity of the surface low and to the north. Otherwise, onshore flow and cloud cover will lead to cooler temperatures compared to previous days, though with dew points remaining high, heat indices will still be above 95 across New Jersey, NYC, and western Long Island.

Link to comment
Share on other sites

You've seen early NWS products/modeling prior to 12z/17.  Please follow all NWS statements/warnings this afternoon tonight.  

PRIMARY max rainfall bands in our subforum of W CT, se NYS, extreme ne PA, n 1/2NJ, LI; ne-sw orientation (I think) roughly ne PA/NNJ through e NYS, NW 1/3 CT. That too where wet microbursts SVR but marginal TT48 instability and max wind below 500MB of about 30 kt.  CAPE plenty supportive of SVR as well HI near 100 in warm sectors which could include KEWR.  Yes TOR possible but not so much dynamically driven (that would mean potentially less strong), more so as spin along a boundary.

Local mesoscale analysis will help with pooling dew points above 70, CAPE, sfc wind convergence as ingredients/drivers of heavy convection (outflows considered too). Moisture, lift and instability!

LI, probably not much till after midnight and then not so much. 

Sunday: lets see what remains... convection possible but much less PW, but still further amounts. Details TBD including whether KEWR nudges 90F?

Am probably offline 230-1030P. Family gathering. 

  • Like 4
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...