Two large rain/wind events 10/25-26, 10/28-30 w probable totals by Oct 31 of 2.5-8" in the NYC subforum, damaging wind and SVR potential for one of these storms

[David-LI]

25 minutes ago, nycwinter said:

news 4 ny still has 1-2 inches on their maps for nyc hmm..

Maybe they had access to 0z GFS before we did.

[nycwinter]

4 minutes ago, David-LI said:

Maybe they had access to 0z GFS before we did.

it was also the same forecast at 6:00pm

[jets]

Still plenty of uncertainty on the exact track 

[LibertyBell]

5 hours ago, thunderbolt said:

It’s funny how we’re all rooting for closer to the coast but we all know damn well if this was in the middle of January we would all be on Suicide watch

I got news for you, if this was in the middle of winter it would still be rain regardless of track- not enough cold air around.  The only difference is in winter it would be 40 and rain.

 

[LibertyBell]

9 hours ago, Allsnow said:

We always get a powerful storm when the nao tanks 

also when it rises rapidly after a tanking

 

[LibertyBell]

11 hours ago, Tatamy said:

12z Euro 10 m AGL Wind Gusts - If you are on LI make sure your generators are ready to go...

even the city is gusting to 50 and near 40 in the Poconos

 

[David-LI]

0z euro is tucked in, 3-4” nyc area, and very windy

[MJO812]

3 hours ago, David-LI said:

Maybe they had access to 0z GFS before we did.

They always go low for every single storm

 I don't get it

[Rtd208]

06Z NAM is very wet for the NYC metro. Rainfall amounts in the 4-6" range.

[SnoSki14]

Models can't figure out if there'll be two lows or one main low. Regardless it looks like a heavy rain event with gusty winds is likely. 

But like the NWS said it's a very low confidence forecast meaning things could end up worse than expected. 

[wdrag]

Loaded is probably one of the best set of short term guidance we have.  Note the 24 hour amounts ending 8PM Tue (general 2+) from the SPC HREF, and the MAX potential of 7-9". WPC risks of flooding seem a little low and conservatively too far east Tuesday. Marginal risk early Tue AM and then slight risk during the day.   There should be some flood problems.

Am pretty sure we'll see 40-50MPH gusts ridges of nw NJ/se NYS while the coast should see gusts 50 MPH except near 70 MPH e LI...most of this during the day Tuesday, possibly ly lingering into Tue eve.   Looks like a little less wind when you get down to the s of I78 but stay tuned for updates. Difficult to believe we'll escape power outages, with most widespread seeming to focus southern C... LI.  

Isolated or scattered embedded thunder appears likely tonight and Tuesday. 

Result is a high impact event , at times, for travel Tuesday in the NYC subforum. 

 

[LongBeachSurfFreak]

4 hours ago, LibertyBell said:

I got news for you, if this was in the middle of winter it would still be rain regardless of track- not enough cold air around.  The only difference is in winter it would be 40 and rain.

 

That’s hard to say. You would need to run the exact pattern with January temps to find out exactly. This could easily be an inland blizzard in January. Coast would see something like March 19.  
It’s been very dry near the coast which could cause rain to runoff faster then normal. Could easily see flash flooding issues in the usual spots.

winds look strong enough to take down a few trees as it’s been a while since we have had winds of the magnitude from that direction with trees in full leaf 

[Rtd208]

Discussions from Mt. Holly and Upton.

Mt. Holly:

 

.NEAR TERM /THROUGH TUESDAY/... 
  This remains a low confidence but potentially high impact forecast.  
  The main features to watch over the next 24 to 36 hours are the  
  closed low currently over the mid Mississippi Valley, the warm front  
  currently bisecting our region, and a mid level short wave trough  
  which was over AL/GA as of the 00Z soundings. The interaction of  
  these features is what is expected to result in cyclogenesis later  
  today off the GA/SC coast which will become the coastal storm to  
  impact our region tonight continuing through Tuesday. 
   
  As mentioned above, this is a low confidence forecast. The warm  
  front is much slower than any of the models had depicted even with  
  the 00Z runs. I am also concerned that at least some models appear  
  to have initialized with the center of the mid level low too far  
  south and east compared to what 00Z soundings and satellite trends  
  would suggest. If there is in fact more separation (distance wise)  
  between the mid level short wave trough and the closed low, then it  
  is possible the coastal low will develop further off shore.  
  Cyclogenesis occuring entirely off the coast is already a  
  notoriously high uncertainty pattern, and the previously mentioned  
  trends just add to my uncertainty with this forecast. 
   
  That being said, this has the potential to be high impact for our  
  region, so here is a summary of the potential hazards through  
  Tuesday: 
   
  Heavy rain: Heavy rain at this point is my biggest concern, and the  
  area of concern hasn`t changed much, generally favoring coastal NJ.  
  There is potential that the axis of heaviest rain could be slightly  
  further south along the southern NJ shore, so Cape May and Atlantic  
  counties were added in to the watch. Additionally, based on guidance  
  trends, increased the QPF slightly.  
   
  Severe Thunderstorms: Limited instability, but significant shear  
  (both speed and directional shear) means that there is potential if  
  any thunderstorms (or even just showers with a stronger updraft)  
  develop, that stronger winds could mix down to the surface.  
   
  As far as timing, expect most of today to be dry, but some initial  
  showers could move in or develop (especially if the warm front is  
  still in the area) by late in the afternoon. The bulk of the rain  
  should be from late this evening through much of the day on 
  Tuesday. 
   
  && 
   
  .SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... 
  Major storm just off the coast will be in the process of pivoting  
  eastward Tuesday night and Wednesday as a digging vort max reaches  
  the Mid-Atlantic. As it reaches the base of the longer-wave trough  
  around 12z Wednesday, the orientation of the vorticity maximum will  
  allow for the increase in eastward momentum of the main upper low by  
  Wednesday afternoon. Of course, a number of questions remain about  
  this process, since the interactions among the various perturbations  
  and the predecessor impacts of widespread precipitation/convection  
  in tandem with the rapidly deepening low are generally low- 
  predictability phenomena. Nevertheless, with the notable model  
  trends on keeping the low closer to the coast and for a little while  
  longer, suspect stronger winds will linger near the coast for a time  
  Tuesday night and Wednesday morning, with gusts exceeding 35 to 40  
  mph probable along the immediate coast. Not out of the question a  
  wind advisory will be needed for these areas. Additionally, showers  
  will likely rotate south-southeastward on the west side of the low  
  in much of the area Tuesday evening, slowly shifting eastward as the  
  low begins its inevitable acceleration offshore. By Wednesday, most  
  if not all of the precipitation should be done for the region, with  
  breezy north winds also gradually declining during the day. Highs on  
  Wednesday should range from the mid 50s in the Poconos to the mid  
  60s in Delmarva. 
   
  Sky cover may diminish Wednesday night as north to northeast winds  
  slowly decrease, which may be favorable for some stronger cooling  
  than on the previous night. Still, think winds will not completely  
  decouple, so forecast lows are mainly in the mid 40s to around 
  50. 
   
  && 

Upton:

 

.NEAR TERM /THROUGH TONIGHT/...
With a warm front north of the area for today, some mid level
ridging will be allowed to momentarily take place. A deep layered
southwesterly flow regime sets up for today allowing temperatures to
warm. As a result dew points readings will get into the lower and
even a few middle 60s, which is rather humid for late October. There
will be some instability into the afternoon and early evening,
however due to an overall lack of forcing not expecting really
anything impactful in terms of sensible weather through the day.

By this evening the jet axis begins to round the base of the upper
level trough off to our west as it swings east. As this occurs the
stronger mid and upper level forcing will begin to get underway.
This should result in moderate to heavy rain to develop towards and
after midnight across the area. Much of the guidance has a potent
mid level shortwave pivoting through during the the overnight
period, followed quickly by strong PVA at 500 mb into Tuesday
morning. The winds at 850 mb also begin to back from the south to
more out of the east. A strong LLJ gets into the region into the day
on Tuesday with a double barrel low type structure. The exact
placement and interactions of the low(s) will determine the
intensity of the LLJ, thus determining where the axis of heavier
rainfall will take place. Also there is the potential for strong
winds. With the low levels becoming more stabilized it will be
difficult to get the stronger winds down to the surface, at least
initially. With some elevated instability and a strong LLJ
developing into Tuesday morning expect more organized heavy rainfall
along with embedded convective elements, a few rumbles of thunder
are possible, if not likely. Over an inch of rain widespread across
the area is looking increasingly likely from midnight to the Tuesday
morning commute.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
Strong forcing due to a strong WAA pattern and the potential for 50
kt or greater easterly winds at 850 mb, along with strong PVA as the
upper level trough axis and 500 mb low gets just south of the area.
This should keep the best lift over the area with periods of heavy
rain throughout much of the day on Tuesday. Some guidance does have
some drying occurring in the mid levels late Tuesday into Tuesday
evening. This will depend on the exact placement of the area of low
pressure. If the low gets further north then some dry slotting may
occur which could bring some of the heavier rain to an end maybe a
few hours earlier than expected. In any event, a significant
rainfall event looks like a proverbial lock due to the deep and
strong WAA / Carlson conveyer belt set up. A strong LLJ gets going
during the day on Tuesday, with the model guidance of the LLJ
placement and intensity varying. Have issued a Wind Advisory for far
eastern sections of CT and LI for late Tuesday and Tuesday night.
There is the potential as the low deepens further and one low begins
to take over that the winds could peak at 45 to 50 mph across far
eastern sections with the winds more out of the northeast and north.
The mostly likely time for this would be during Tuesday evening and
into the first half of the overnight as the low may get slightly
further to the east. The heavier rain would then end from west to
east based on the latest timing. With the center of circulation
potentially getting further east as the low gets more vertically
stacked the storm should get to its peak in terms of intensity and
lower surface pressure readings. Rainfall totals as this time look
to be on the order of 2 to 4 inches. HREF 24 hr. PMM QPF has
localized amounts of 5 to 7 inches which is tough to come by.
Hopefully this scenario does not come to fruition as this would lead
to widespread flooding issues. Thus continuing with the Flood Watch
across the entire area for tonight into the day on Tuesday.

On Wednesday the low will gradually get further offshore, especially
by the afternoon. The current thinking has chance POPs giving way to
slight chance POPs from west to east through the day as the back
edge of any rainfall begins to pivot off to the east. With
completely dry conditions returning by the late day and evening with
mostly cloudy skies giving way to some clearing during this time
frame. A gusty northerly flow will have temperatures running near
normal with mainly lower 60s for afternoon highs.

&&

[thunderbolt]

4 hours ago, LibertyBell said:

I got news for you, if this was in the middle of winter it would still be rain regardless of track- not enough cold air around.  The only difference is in winter it would be 40 and rain.

 

That’s not true if it was more east and There was blocking this would definitely be snow And then hence that’s why I  Said January the odds of it being colder are a lot greater

[qg_omega]

Overnight trend was northeast instead of the tuck, GFS has been on this and Euro has been much more tucked.  Early battle on the Euro vs GFS.  I would lean GFS based off past model performance

[MJO812]

11 minutes ago, qg_omega said:

Overnight trend was northeast instead of the tuck, GFS has been on this and Euro has been much more tucked.  Early battle on the Euro vs GFS.  I would lean GFS based off past model performance

What models were northeast?

[MJO812]

51 minutes ago, bluewave said:

The core is starting out warmer now. So the exact track on the 12z runs will be very important. Euro already has 70 mph gusts on Eastern Long Island. It also has an impressive sting jet south of the center. The wind gust product was improved on the recent upgrade to avoid the gusts being too high. So the tests that I saw looked more realistic.
 

 

 

JB is hinting that there might be hurricane force winds in Eastern LI.

[David-LI]

12z HRRR fwiw

[David-LI]

12z NAM is very wet for NYC area. 3-5" by 1pm Tuesday with still more to come.

[MJO812]

7 minutes ago, David-LI said:

12z NAM is very wet for NYC area. 3-5" by 1pm Tuesday with still more to come.

More to come

Double barrel low

 

 

[MJO812]

We have an orange 

[David-LI]

Based off 12z NAM, most rainfall occurs overnight tonight into tomorrow. Winds don't seem to be very strong until late in the evening tomorrow as the low pivots back.

[MJO812]

3 minutes ago, David-LI said:

Based off 12z NAM, most rainfall occurs overnight tonight into tomorrow. Winds don't seem to be very strong until later in the evening as the low pivots back.

6z eps is all clustered tucked in except for a few stragglers 

[BombsAway1288]

1 hour ago, David-LI said:

Based off 12z NAM, most rainfall occurs overnight tonight into tomorrow. Winds don't seem to be very strong until late in the evening tomorrow as the low pivots back.

If the winds are really that strong we run the risk of numerous power outages thanks to freshly saturated ground ala March 2010

[MJO812]

12z gfs

[tek1972]

With my untrained eye on the GFS this looks just slightly too far east to cause significant wind damage west of the twin forks. Thoughts?

Sent from my SM-G998U using Tapatalk

[bluewave]

The 3km Nam has 70 mph gusts close to Eastern Long Island. But the exact location of where the cyclonic loop occurs will be important. Models may be struggling on where to place the subtropical system with the multiple weaker lows to the west. 
 

[SnoSki14]

4 hours ago, qg_omega said:

Overnight trend was northeast instead of the tuck, GFS has been on this and Euro has been much more tucked.  Early battle on the Euro vs GFS.  I would lean GFS based off past model performance

We'll see. The rain impacts will be the same regardless due to the double barreled low structure. 

[jets]

Crazy how many Euro members bring this just off NJ. Nowcast mode in effect

[nycwinter]

latest  rainfall future cast amounts by the local mets seem to be heaviest from the city now west rather then east.