OBS-Discussion Flash Flood rainfall potential through 4AM Tuesday 7/15/25, especially I95 corridor

[wdrag]

Good Monday morning everyone. Please follow anticipated NWS warnings-statements later today.  Already as of 530AM 1/4-1/2" amounts fell earlier today in NNJ.

Watches are posted where potential exists for localized excessive rainfall by Tuesday morning, isolated 5-6" totals possible, mainly NJ portion of our NYC subforum.

An impaired Monday evening commute is anticipated with delays-accidents-possible detours. Plan accordingly. 

Recent humid but no rain scenario of past several days limits any mainstream flood potential but creeks-small streams, and especially urban areas along I95 are vulnerable to short fuse excessive rainfall, life threatening flooding if caught in overflowed roads.   

Turn around-don't drown should be in the back of all motorists minds. 

Added SPC HREF average rainfall and maximum potential rainfall graphic by Tuesday evening (most of this occurring 2PM-Midnight today). The WPC excessive rainfall forecast.  Also the 5AM WPC 7 day rainfall anticipated by the 21st and depiction of NWS watches lager today. 

 

[Brian5671]

On the eastern fringe of it all here...we sure could use some rain.   6z Models seem to like the Hudson west for heaviest.

[LongBeachSurfFreak]

And…. We will be lucky to crack a tenth on the island.(south shore mainly)This looks almost entirely instability based and with no focusing mechanism the usual suspects are prime. 

[jm1220]

1 minute ago, LongBeachSurfFreak said:

And…. We will be lucky to crack a tenth on the island.(south shore mainly)This looks almost entirely instability based and with no focusing mechanism the usual suspects are prime. 

Yep. Looking forward to seeing NJ/Hudson Valley get nailed again and it hitting the Hudson River brick wall. Sprinklers are staying on. 

[LongBeachSurfFreak]

Just now, jm1220 said:

Yep. Looking forward to seeing NJ/Hudson Valley get nailed again and it hitting the Hudson River brick wall. Sprinklers are staying on. 

The timing is just off. This is one of those scenerios where New Jersey gets crushed today, decaying showers cross the western island overnight only ramp back up and slam the east end and southern New England tomorrow. It’s always amazed me how that timing always seems to play out.

[donsutherland1]

For reference:

[winterwx21]

I don't want major flooding, but hoping for some heavy rain today because it's so dry out there. I see the latest HRRR (14z) crushes my area with 5 inches of rain, but we know how HRRR is. It moves around from run to run and is wildly inconsistent. Obviously some spots will get very heavy rain amounts today while others get little to nothing. Who knows. 

[Stormlover74]

27 minutes ago, winterwx21 said:

I don't want major flooding, but hoping for some heavy rain today because it's so dry out there. I see the latest HRRR (14z) crushes my area with 5 inches of rain, but we know how HRRR is. It moves around from run to run and is wildly inconsistent. Obviously some spots will get very heavy rain amounts today while others get little to nothing. Who knows. 

Even though my basement doesn’t flood anymore I'm hoping we don't see that much especially while I'm not there.  

[forkyfork]

i think at least one asos in the immediate metro breaks 2"

[forkyfork]

slight risk expanded into the metro

[BxEngine]

Anlther sick hrrr performance of showing no rain anywhere in its first 2 hours…andddddd its pouring. Probably enough to kill any slight chance risk for tnite  

[SnowGoose69]

2 minutes ago, BxEngine said:

Anlther sick hrrr performance of showing no rain anywhere in its first 2 hours…andddddd its pouring. Probably enough to kill any slight chance risk for tnite  

HRRR its last 2 runs seems to be getting the yips and being fooled a bit by the cloud cover from SW NY back through NE PA.  Its got notably less activity overall than it did 3-4 runs ago.  But with the triggering mechanisms in place I'd be surprised if coverage was not widespread anyway

[Brian5671]

Not sure why anyone takes the HRRR seriously...

[Stormlover74]

6 minutes ago, Brian5671 said:

Not sure why anyone takes the HRRR seriously...

What else do we have?

[Brian5671]

6 minutes ago, Stormlover74 said:

What else do we have?

3K NAM and RGEM are often better

[BxEngine]

54 minutes ago, Brian5671 said:

Not sure why anyone takes the HRRR seriously...

I dont. I mock it endlessly. The NAM at 6 hrs is better than hrrr at 0 hr and we’re replacing the nam….thats amazing. 

[Brian5671]

47 minutes ago, BxEngine said:

I dont. I mock it endlessly. The NAM at 6 hrs is better than hrrr at 0 hr and we’re replacing the nam….thats amazing. 

Agreed, it's good to show that a given day will have activity but the placement of rain is often all over the place

[Snowlover11]

You get a storm, You get a storm, my area you don’t get a storm.

[winterwx21]

A small downpour just missed me to the south by a mile or two. Hoping for some heavy rain later...

[uofmiami]

9 minutes ago, Brian5671 said:

URGENT - IMMEDIATE BROADCAST REQUESTED
   Severe Thunderstorm Watch Number 484
   NWS Storm Prediction Center Norman OK
   130 PM EDT Thu Jul 3 2025

   The NWS Storm Prediction Center has issued a

   * Severe Thunderstorm Watch for portions of 
     Connecticut
     Massachusetts
     Northern New Jersey
     Southern New York
     Northeast Pennsylvania
     Rhode Island
     Coastal Waters

   * Effective this Thursday afternoon and evening from 130 PM until
     1000 PM EDT.

   * Primary threats include...
     Scattered large hail and isolated very large hail events to 2
       inches in diameter possible
     Scattered damaging wind gusts to 70 mph possible

   SUMMARY...Thunderstorm coverage and intensity should increase this
   afternoon across the region amid strengthening large-scale ascent
   and airmass destabilization. Moderate to strong buoyancy coupled
   with moderate vertical shear will support organized storm structures
   capable of large hail and damaging gusts. Large hail will be the
   primary risk with the early-stage cellular development while strong
   winds will be more likely once storms transition towards a more
   linear mode.

That's from July 3rd!

[Brian5671]

3 minutes ago, uofmiami said:

That's from July 3rd!

deleted it

[winterwx21]

12 minutes ago, Brian5671 said:

Agreed, it's good to show that a given day will have activity but the placement of rain is often all over the place

Occasionally the HRRR turns in a great performance, but no question it's bad more often than it's good. I see the latest 17z run is back to showing much more activity and crushes a lot of the area this evening. We shall see. 

[Snowlover11]

nvm about to pour here.

[LongBeachSurfFreak]

Nice sunny day at the beach after some morning clouds. Sea breeze is cranking right now. Going to stay dry here as expected. 

[Snowlover11]

Ripping here in Nanuet, Heavy rain, a few bursts of wind and some booms.

[Sundog]

18 minutes ago, LongBeachSurfFreak said:

Nice sunny day at the beach after some morning clouds. Sea breeze is cranking right now. Going to stay dry here as expected. 

Ironically out of the last 4 days today is the clearest, sunniest day at the beach

[Snowlover11]

some very board rotation

[Brian5671]

1 minute ago, Sundog said:

Ironically out of the last 4 days today is the clearest, sunniest day at the beach

strong south winds here keeping the cloud deck and rain inland

[BxEngine]

Welp i was wrong lol. Getting CRUSHED. Heavy winds, constant lightning, really really heavy rain rates.

[Snowlover11]

1 minute ago, BxEngine said:

Welp i was wrong lol. Getting CRUSHED. Heavy winds, constant lightning, really really heavy rain rates.

me too. was ripping, sun’s peaking out behind the little line. frequent booms.