August 2017 Observations & Discussion Thread

[NJwx85]

[Stormlover74]

Looks different now

[forkyfork]

we won't know the jackpots until the convection has actually formed

[Rtd208]

Very muggy out there tonight. Any showers and thunderstorms that develop overnight and tomorrow are going to produce some very heavy rain.

Current temp 74/DP 72/RH 90%

[Rtd208]

...Middle Atlantic states northward into NY/CT...
   Scattered early-day cloud cover, associated with a plume of
   mid-level moisture from the TN Valley into the Mid-Atlantic states,
   will give way to strong heating from PA/NJ southward.  A
   moisture-rich airmass sampled by Thursday evening RAOBS (reference
   the Dulles sounding) will become moderately to strongly unstable by
   mid afternoon from the Mid-Atlantic to southern NY.  Models show the
   strongest mid-level flow will generally remain north of central VA
   with effective shear increasing from 25-40 kt with northward extent.
    
   The combination of weak ascent associated with a mid-level vorticity
   maximum (forecast to move from IN to PA during the day), and a weak
   cap and strong heating in the lee of the higher terrain, will favor
   scattered to numerous storms developing during the afternoon from
   central VA northward into the lower Hudson Valley.  Forecast
   soundings show MLCAPE 1500-3000 J/kg and 70s degrees F boundary
   layer dewpoints.  A mixed mode of multicells and perhaps a couple of
   supercells will favor isolated gusts around 60 mph---conducive for
   scattered wind damage.  A marginal risk for a tornado is possible
   from the Chesapeake Bay vicinity north into the lower Hudson Valley.
    Forecast hodographs are largest over the Delaware River Valley
   north into southeast NY during the late afternoon/early evening.  A
   gradual weakening in storm intensity is expected by the early-mid
   evening as the activity moves towards the coast. 

[Rtd208]

Mt.Holly:

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Mount Holly NJ
339 AM EDT Fri Aug 18 2017

DEZ001-002-MDZ008-012-015-019-020-NJZ001-007>010-012-013-015>019-
PAZ060>062-070-071-101>106-181545-
/O.NEW.KPHI.FF.A.0007.170818T1800Z-170819T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Kent-Cecil-Kent MD-Queen Annes-Talbot-Caroline-Sussex-
Warren-Morris-Hunterdon-Somerset-Middlesex-Western Monmouth-
Mercer-Salem-Gloucester-Camden-Northwestern Burlington-Berks-
Lehigh-Northampton-Delaware-Philadelphia-Western Chester-
Eastern Chester-Western Montgomery-Eastern Montgomery-Upper Bucks-
Lower Bucks-
Including the cities of Wilmington, Dover, Elkton, Chestertown,
Centreville, Easton, Denton, Newton, Washington, Morristown,
Flemington, Somerville, New Brunswick, Freehold, Trenton,
Pennsville, Glassboro, Camden, Cherry Hill, Moorestown,
Mount Holly, Reading, Allentown, Bethlehem, Media, Philadelphia,
Honey Brook, Oxford, West Chester, Kennett Square, Collegeville,
Pottstown, Norristown, Lansdale, Chalfont, Perkasie, Morrisville,
and Doylestown
339 AM EDT Fri Aug 18 2017

...FLASH FLOOD WATCH IN EFFECT FROM 2 PM EDT THIS AFTERNOON
THROUGH THIS EVENING...

The National Weather Service in Mount Holly has issued a

* Flash Flood Watch for portions of southwestern, central and
  northwestern New Jersey, eastern Pennsylvania, central and
  southern Delaware and northeastern Maryland.

* From 2 PM EDT this afternoon through this evening

* Multiple rounds of showers and thunderstorms can be expected
  through tonight. While flash flooding is not anticipated with
  the initial round this morning, locally higher rainfall amounts
  of 1 to 2 inches are possible, and will help saturate the ground
  for the next round of storms. Torrential downpours with storms
  that develop this afternoon and evening could produce rainfall
  rates greater than 2 inches per hour. While the entire area will
  not receive heavy rain, isolated rainfall totals of 3 to 6
  inches are possible where storms track over the same locations.

* Torrential rain falling in a short period of time will result in
  rapidly rising water levels along streams and creeks and in
  areas of poor drainage. Significant roadway flooding is possible
  in isolated areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flash Flood Watch means that conditions may develop that lead
to flash flooding. Flash flooding is a very dangerous situation.

You should monitor later forecasts and be prepared to take action
should Flash Flood Warnings be issued.

Basement flooding is possible due to heavy rain falling on soils
already saturated from previous storms. If your home has a history
of basement flooding, monitor your sump pump for proper operation
and if possible, direct outside water flow away from your house


&&

$$
Klein

[CIK62]

GFS dispenses with three separate suspicious areas while the CMC at its usual self, keeps all three, and crushes NYC  with one of them, near the 27th.

Happy tracking to all.

[ForestHillWx]

Heavy rain for about 25 minutes with round 1. Should be a fun, waterlogged day. 

[NJwx85]

1 hour ago, CIK62 said:

GFS dispenses with three separate suspicious areas while the CMC at its usual self, keeps all three, and crushes NYC  with one of them, near the 27th.

Happy tracking to all.

The Euro now sends Harvey into the GOM as a major hurricane.

[NJwx85]

0.48" already.

[bluewave]

Highest humidity at JFK so far for August with a 75 dewpoint. It should really pour in the spots that get the best storms today.

[dmillz25]

Incoming should pour for about 30 min

[JerseyWx]

Had an extremely heavy downpour around 7:00 am.  

[Rtd208]

Made a thread for today's heavy rain, flooding & severe storms.

[Tatamy]

12 hours ago, forkyfork said:

we won't know the jackpots until the convection has actually formed

I jackpotted this morning with the convection in my area.  1.63" with a loud crashing thunderstorm at 5am. 

[Cfa]

Low of 76 here, which is the warmest so far this August. It probably won't hold if we manage to see more than a few drops of rain here, in the Atacama.

[Paragon]

18 minutes ago, Cfa said:

Low of 76 here, which is the warmest so far this August. It probably won't hold if we manage to see more than a few drops of rain here, in the Atacama.

75/75 at JFK right now!

[CIK62]

http://www.pivotalweather.com/model.php?m=ggem&p=sfcwind_mslp&rh=2017081800&fh=228&r=conus&dpdt=

[psv88]

CRUSHED

[uofmiami]

1.91" in Muttontown so far.  It literally dumped in no time:

 

[Paragon]

2 minutes ago, uofmiami said:

1.91" in Muttontown so far.  It literally dumped in no time:

 

Looks like the heavy rain is extending a bit to the southwest.  More downpours occurring here now, but they don't last long.

I was wondering something- if the ocean has a stabilizing effect, why is it that the south shore of LI seems to be a black hole for convective precip yet the Jersey Shore does so well with it?  Monmouth County (just 15 miles S of JFK) especially- both in summer and winter!

Maybe the orientation of the shoreline has something to do with it (north-south vs east-west.)

[Rjay]

Heavy rain with lightning and thunder in North Merrick.  A couple of downpours in Massapequa Park.  I'm sure the Wantagh mesonet won't show too much rain as the areas further south looked to have received much less rain.  

[Paragon]

7 minutes ago, Rjay said:

Heavy rain with lightning and thunder in North Merrick.  A couple of downpours in Massapequa Park.  I'm sure the Wantagh mesonet won't show too much rain as the areas further south looked to have received much less rain.  

The heavy rain is backbuilding to the SW, really heavy rain here now.

[Rjay]

2 minutes ago, Paragon said:

The heavy rain is backbuilding to the SW, really heavy rain here now.

Might have spoken too soon.  Sinking south towards Merrick Road.

[Rjay]

Flash flood warning for western Suffolk 

[Paragon]

Just now, Rjay said:

Might have spoken too soon.  Sinking south towards Merrick Road.

What I'm wondering is, is this the appetizer or the main course?  Will what we get later in the day/tonight be better than this?  We've been fooled by this kind of thing before, where we got an early morning deluge but the storms that were progged for later fizzled out.

[Rjay]

Forgot there was a thread for this event.  My bad. 

[Paragon]

5 minutes ago, Rjay said:

Forgot there was a thread for this event.  My bad. 

Well the sun is out now, so I guess we can go back to talking about the high dewpoints here

Still 75/75 even after the rain ended and the sun came out.

[Stormlover74]

56 minutes ago, Paragon said:

What I'm wondering is, is this the appetizer or the main course?  Will what we get later in the day/tonight be better than this?  We've been fooled by this kind of thing before, where we got an early morning deluge but the storms that were progged for later fizzled out.

I think this was the main show

[bluewave]

41 minutes ago, Paragon said:

Well the sun is out now, so I guess we can go back to talking about the high dewpoints here

Still 75/75 even after the rain ended and the sun came out.

Highest dewpoint of summer in Wantagh now at 75.

http://www.nysmesonet.org/mesonow#?stid=WANT