Event Discussion-OBS uncertain tracking thread for possible moderate impact event 8A Thu-8A Fri 10/30-31. Mainly 1-3" rains, G 45-55 MPH-mainly coast, and high prob of at least minor coastal flooding - Thursday afternoon high tide cycle.

[wthrmn654]

Flash flood warning

[WeatherGeek2025]

that was some crazy rain with wind in midtown earlier. Heaviest rain i've seen in years probably

[BxEngine]

Banning everyone who claimed it would bust. The bronx is a mess. 

[SI Mailman]

1.6 inches over here

[Brian5671]

guess we are up next as it moves east

[bluewave]

44 minutes ago, steve392 said:

Did this system tap tropical moisture from Melissa? 

 

Yes. 
 

https://www.wpc.ncep.noaa.gov/metwatch/metwatch_mpd_multi.php?md=1220&yr=2025

However, OSPO's ALPW has since shown an
increase stemming from Melissa's circulation, especially near and
below 700 mb, being drawn northward into NJ and southern NY. The
continued addition of this remnant tropical moisture should allow
for an increase in rainfall efficiency and locally higher rainfall
rate potential into the early evening hours.

[MJO812]

Brooklyn

[donsutherland1]

Through 3:25 pm, Newark has picked up 1.91" of rain today. That breaks the daily record of 1.57" from 1955. Through 3:32 pm, LaGuardia Airport has seen 1.41" of rain. That breaks the daily mark of 1.18" from 1955.

[wthrmn654]

.HYDROLOGY...

-- Changed Discussion --

Instantaneous rainfall rates with a narrow convective line moving through attm have come close to an inch in only 10 minutes in parts of NYC, with storm totals over 2 inches, causing flash flooding in spots. Widespread rainfall of 1.5-2.5 inches expected through tonight, with widespread nuisance flooding likely. Local amts as high as 3-4 inches, and rates up to an inch in less than an hour, will also present a localized flash flood risk mainly from western CT/Long Island north/west.

-- End Changed Discussion --

[Dark Star]

47 minutes ago, steve392 said:

Is this system over performing?  Been non-stop heavy rains all afternoon. 

That's almost always debatable.  The rain is "showery" in nature.  Most of the day featured on and off showers, mainly light in nature, with some heavier downpours.  But, depending upon your exact location, you may have had more persistent heavier bursts.  Certainly Northeastern PA was a bullseye, as forecast.  Seems like your area was another bullseye.  We had a snowstorm, I think within the last 10 years that was extremely spotty, some areas getting 20"+ and other areas 5", from town to town.  I can't remember a snowstorm that was that "convective" before.  Then within a week or so later, another snowstorm was forecast.  Storm Field was predicting the exact same thing, extreme variations in totals, as though suddenly this was a new trend.  The snowfall amounts in the 2nd storm were much more uniform.  

[the_other_guy]

At 230 I saw the radar and picked up the kids from school early. Sometimes its good to be in the know haha

 

At least this was relatively short. If there was more behind, we would have big problems

[Dark Star]

3 hours ago, donsutherland1 said:

Through 3:25 pm, Newark has picked up 1.91" of rain today. That breaks the daily record of 1.57" from 1955. Through 3:32 pm, LaGuardia Airport has seen 1.41" of rain. That breaks the daily mark of 1.18" from 1955.

Holy crap, around noon time, Newark only had 0.75" (the NWS is only showing 1.15" for Newark airport?)  We did get some heavier downbursts after 12 pm to about 2 PM.  No flooding in the immediate area.  But looks like NYC received a heavier band that was somewhat training over the area.  I see Newark updated its rain totals, reflecting what you said earlier...

[hudsonvalley21]

Rain rate of 3.56” currently. 1.77” so far.

[wthrmn654]

 

Mesoscale Precipitation Discussion 1220
NWS Weather Prediction Center College Park MD
332 PM EDT Thu Oct 30 2025

Areas affected...northern NJ into southern NY/Long Island and CT

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

Valid 301931Z - 310125Z

Summary...Heavy rain across the Tri-State Area through this
evening may result in localized flooding/flash flooding. Localized
rainfall totals over 3 inches will be possible. Rainfall near 1
inch in 15-30 minutes can be expected.

Discussion...19Z radar imagery showed a low-topped squall-line,
oriented from south to north, edging east from 40 miles east of
ACY through NYC. This line was being aided by strong low level
convergence with 45-50 kt from the SSE/SE in the 925-850 mb layer,
located north of the triple point of an occluded cyclone over the
northern Mid-Atlantic region. The line of showers has been
accompanied by 0.50 to 1.00 inches of rain in 15 minutes across
northern NJ into the Five Boroughs.

Moisture from the Mid-Atlantic coast into southern New England was
already anomalous as sampled by area 12Z RAOBs, with PWAT values
of 1.2 to 1.5 inches. However, OSPO's ALPW has since shown an
increase stemming from Melissa's circulation, especially near and
below 700 mb, being drawn northward into NJ and southern NY. The
continued addition of this remnant tropical moisture should allow
for an increase in rainfall efficiency and locally higher rainfall
rate potential into the early evening hours.

While the line of showers has been progressive, there is some
concern for very brief slowing/stalling given the LEWP-like
appearance off the NJ coast, which could result in a quick 1-2
inches as this line continues to advance east through the
remainder of the afternoon. As a triple point low becomes better
organized south of Long Island this evening, low level flow will
maintain a southeasterly orientation, with possible backing.
Therefore, some orographic component to lift will be added into
the equation for the higher terrain north and west of I-95,
combining with increasing right-entrance jet ascent associated
with a forecast 130 kt jet streak on the east side of the parent
upper low to the west.

Farther south and west, instability is expected to remain weak
(briefly peaking in the 500-1000 J/kg range) but perhaps
sufficient to support a few additional heavy showers from eastern
PA and southern NJ, rotating northward into the Tri-State region.

Additional rainfall may result in isolated areas of rapid
inundation of water. Given below average rainfall over the past
few weeks and ongoing drought conditions across portions of the
region, any flooding that occurs is likely to remain constrained
to urban or other areas with poor drainage.

Otto

[Uniblab]

2.09 Staten Island north shore. 

[Sundog]

Heavy rain but bizarrely calm winds. It's dead calm. 

[ag3]

Insane rain. Station over 2” now

[weathermedic]

2.77 inches at my station

[Stormlover74]

Sun is out

[Cfa]

It has looked nighttime nearly all day with little rain to show for it.

[psv88]

Pitch black and like a tropical storm in western Suffolk. 0.55” on the day but the squall line hasn’t made it yet 

[donsutherland1]

As of 4 pm, New York City has seen 1.81" of rain. That breaks the daily record of 1.64" that was set in 1917. The hourly figure from 3 pm - 4 pm of 0.83" surpassed the hourly record for October 30 that was set during 1955.

[Sundog]

2.25 inches here after this deluge worked its way through. 

Very satisfied. Also happy that winds have completely died. 

[Brian5671]

ramping up here but looks a bit weaker than what the city got

[wdrag]

Another band of showers, some very briefly mdt-havy for NNJ-NYC NYS this eve as the 5H sort-trough axis and  about 150M 12 hr Height Fall Center axis passes through, then the sfc wind turns west and drying begins with gusts 40 MPH tomorrow afternoon ,.  As of now not planning  a new thread for marginal wind alone tomorrow.  I think today will have equaled or exceeded what ever tomorrow brings. 

[steve392]

Well that was definitely a storm we needed!  Wish I had my rain guage set up.  Sun is making an appearance to my west. 

[Brian5671]

yep much needed rain for all of us...

[ag3]

2.33” on my station

[uofmiami]

2.23" in Syosset & 2.04" in Muttontown so far.

[uofmiami]

58 minutes ago, Sundog said:

2.25 inches here after this deluge worked its way through. 

Very satisfied. Also happy that winds have completely died. 

Round 2 of the winds tomorrow to blow away the trick or treaters it seems.  My daughter isn't going to be happy.