Tropical connection NYC forum area Sun-Wed, 8/2-5/20- Tropical Storm Isaias

[wdrag]

Good Thursday morning,

Decided to start a combined topic covering Saturday night, Sunday afternoon and the uncertain impact of ISAIAS this coming Monday-Tuesday.  ISAIAS has track uncertainties until everything gets re-organized Friday.  Thereafter, I think the EPS/GEFS should nail whether or not tropical storm conditions can impact the coasts.  Follow NHC guidance and the contributions from American Weather tropical experts. 

One reason for uncertainty; I see multiple 00z/30 ensembles showing the northern bounds of heavy rainfall not too far north of our NYC forum which suggests, at this distant date, that a hard right turn of ISAIAS could yet occur that would spare us more than a dangerous rip current situation. In other words, we're on the gradient of substantial rainfall impact. Big forecast busts tend to occur in the ensemble gradients, buying in too early to one set of solutions or another. 

So dangerous rip currents are my first primary concern for Monday-Wednesday, especially Long Island. Southerly swells should gradually build over the western Atlantic into early next week. 

Presuming the NHC 5AM Thursday track is reasonable, surge and wind field risks on the western side of ISAIAS are minimal but if the track shifts to where a portion of our area is on the eastern side of the TC, then those risks would significantly increase.

My secondary primary concern is isolated 7" rainfall from the necessary combined events of Saturday nights WAA (warm frontal) event, Sunday afternoons possible isolated severe nw NJ/se NYS westward into ne PA,  and then finally either a PRE, or a direct impact of ISAIAS Monday-Tuesday. I'm more concerned about Predecessor Rainfall event rather than direct ISAIAS impact.  The 7" rainfall in my estimation would probably have to occur west of the I95 corridor due to the ensembles probable combined Sat night-Sunday afternoon events depositing biggest amounts somewhere near the western edge of our forum coverage (~Sussex-Orange Counties?).  If Sat night-Sunday does not occur (1-3" combined event band somewhere in that area), then a PRE or ISAIAS hit would have to do all the work by itself and at this time, this is far too uncertain. So to get to 7", it's a lot easier if we see sizable rainfall Sat night-Sunday.  

There is still a chance not much happens here next Monday-Tuesday-it's in the envelope of possibilities. (See the 06z/30 GFS run). 

Let's see what happens. I'll be particularly interested in PRE comments.  733A/30

 

[Brian5671]

Great discussion Walt.  I think another factor will be how this thing looks once it gets over Hispanola.  It's a weaker system now so maybe that works in its favor vs a hurricane which sees it's circulation disrupted by the large mountains and never recovers.

[Allsnow]

[Brian5671]

4 minutes ago, Allsnow said:

move up through central CT after that-nice rainstorm for many with wind...system is rocketing NNE from this point on

[PB-99]

[PB-99]

[SnoSki14]

This should be interesting. We've already had a TS so I guess there's some precedent for another one. 

Models are all over the place when it comes to intensity though. 

[forkyfork]

those gust maps are weenie nonsense

[Stormlover74]

Just now, SnoSki14 said:

This should be interesting. We've already had a TS so I guess there's some precedent for another one. 

Models are all over the place when it comes to intensity though. 

I'm surprised models have been showing relatively little intensification once away from the islands. I would think if stays off the coast of Florida it could definitely ramp up

[PB-99]

[forkyfork]

do you really think long island is going to get 120 mph gusts? come on

[Santa Claus]

10 minutes ago, PB-99 said:

The relative consistency of the Euro is becoming concerning.  EDIT: to clarify, the track.

I hate myself for asking this but there's no chance of blocking and a Sandy event is there?  We have had some unusual flow patterns this summer, cutoff and retrograding lows.

[PB-99]

It`s just model output.

The Euro has a 2 in the S/E coming up pretty quickly. How much does it weaken on it`s way if the Euro is right ? 

I wouldn`t just ignore it. 

[Brian5671]

Just now, PB-99 said:

It`s just model output.

The Euro has a 2 in the S/E coming up pretty quickly. How much does it weaken on it`s way if the Euro is right ? 

I wouldn`t just ignore it. 

I wouldn't ignore anything the Euro puts out on tropical systems.  However, seems early for this kind of hit-usually see it late Aug and on...but this year is busy so who knows.

[forkyfork]

2 minutes ago, PB-99 said:

It`s just model output.

The Euro has a 2 in the S/E coming up pretty quickly. How much does it weaken on it`s way if the Euro is right ? 

I wouldn`t just ignore it. 

ryan maue makes weenie maps to get more clicks. there's no way those gusts are happening with a weakening post tropical system

[PB-99]

1 minute ago, Will - Rutgers said:

The relative consistency of the Euro is becoming concerning.

I hate myself for asking this but there's no chance of blocking and a Sandy event is there?  We have had some unusual flow patterns this summer, cutoff and retrograding lows.

The slot in up the E/C and not bending W  

 

It should slip between the WAR and the Trough 

 

[Santa Claus]

6 minutes ago, Stormlover74 said:

I'm surprised models have been showing relatively little intensification once away from the islands. I would think if stays off the coast of Florida it could definitely ramp up

There's a lot of sheer over the east coast and coastal waters.  Something to watch

[PB-99]

10 minutes ago, forkyfork said:

ryan maue makes weenie maps to get more clicks. there's no way those gusts are happening with a weakening post tropical system

If this comes out of the SE after venting nicely, you can`t see 100 mph gusts on the east side ? if it comes up the slot ? 

 

[PB-99]

It`s a robust run, but it`s not like the UKMET isn`t seeing it. 

[forkyfork]

1 minute ago, PB-99 said:

If this comes out of the SE after venting nicely, you can`t see 100 on the east side ? if it comes up the slot ? 

 

no

[forkyfork]

the euro developed a tropical storm over inland texas from an MCS a few weeks ago. it's been bad with this stuff lately 

[Brian5671]

will also pull in dry air from the continent-see Irene.  

[PB-99]

UKMET has a similar track.

 

 

 

 

[MJO812]

Water temps are really warm

[Santa Claus]

What kind of interaction might it have with that deep trough?  It might just get captured.

[PB-99]

9 minutes ago, forkyfork said:

no

We are speaking about gusts tho. IDK man, that could track due N over some really warm water once off OBX and because of it`s speed not lose alot if it`s intact in the S/E.

I guess we will know more after it gets away from Hispaniola.

[PB-99]

15 minutes ago, Brian5671 said:

will also pull in dry air from the continent-see Irene.  

Yes, but this will not be cut off from the flow.

It`s the speed at which it comes N that could keep the east side intact all the way to LI. 

It`s early I agree. 

[Santa Claus]

Looking pretty solid right now.

One thing about the potential storm surge into LI is that many of these models think this thing is going to be absolutely flying up the coast.  From what I've read the higher the forward speed, the higher the storm surge height, but the less overall land mass that gets flooded.

[Brian5671]

17 minutes ago, PB-99 said:

Yes, but this will not be cut off from the flow.

It`s the speed at which it comes N that could keep the east side intact all the way to LI. 

It`s early I agree. 

Something to track!

[jm1220]

When storms are recurving NE near our area, they are often choking on dry air, getting sheared quite a bit and affected by cool waters. Water here is warmer than normal but not enough to sustain a near major hurricane. I would say at max it would be a strong TS up here. I’d hope to be on the west side where the rain would be. Also more likely is it tracks NE from Cape Hatteras and is entirely out to sea other than high waves.