9/30-10/5 Joaquin-Trough Interaction-DISCUSSION/OBS

[IsentropicLift]

Another wet period on the 12z EPS mean from Saturday night through Monday.

 

Adding up the individual panels I came up with around 4-5" for NYC.

[Juliancolton]

Any chance of a dedicated model thread? This one is a bit hard to read, if you're looking for actual analysis/current conditions.

[Northshore Blizzard]

The storm totals that OKX had put up early this morning was through Friday 6pm; this map only goes out thru Thursday 6am.

 

                   

 

 

Appears OKX has trimmed expected rainfall amounts by half from what they were this morning:

 

[Brian5671]

Appears to be two main camps on the 12z EPS individual members, one which moves the system northeast like the OP and the other which landfall the system either into the NC or VA coast.

makes sense...the hurricane models are roughly in that camp too with a 3rd camp into SE NE

[forkyfork]

The EPS mean appears further west with Joaquin than the OP since the blocking ridge east of

New England is stronger.

in these cases it's best to treat the op run as an ensemble member. this could be a case of the op euro being too dig happy

[stormwarn]

The storm totals that OKX had put up early this morning was through Friday 6pm; this map only goes out thru Thursday 6am.

 

                   

 

Yes, correct, which clearly indicates the uncertainty with this forecast.

[BxEngine]

Yes, correct, which clearly indicates the uncertainty with this forecast.

What was it cut down from? You cant claim it was cut if you arent comparing the same timeframes.

[wthrmn654]

This morning it was showing 4 inch amounts, I think what he was trying to say was that since the tropical storm is very much un certain, they took it out of there projected rainfall map.

What was it cut down from? You cant claim it was cut if you arent comparing the same timeframes.

[Stebo]

in these cases it's best to treat the op run as an ensemble member. this could be a case of the op euro being too dig happy

Very good point, especially with a highly anomalous pattern like this one.

[Rjay]

This morning it was showing 4 inch amounts, I think what he was trying to say was that since the tropical storm is very much un certain, they took it out of there projected rainfall map.

That map is valid from 8am Tuesday through 6am Thursday.

[wthrmn654]

NOAA9 Mission #WA into JOAQUIN

Type: Upper-level / Dropsonde | Status: In Progress

As of 20:27 UTC Sep 29, 2015:

Aircraft Position: 27.88°N 71.25°W

Bearing: 0° at 360 kt

Altitude: 13477 gpm

Peak 10-second Wind: 11 kt at 80°

Extrapolated Sea-level Pressure: N/A

[Drz1111]

 The equatorward outflow from Joaquin is amazingly good - its remarkably well-ventilated for such a sheared storm.  That (and the bathtub SSTs) is why the convection is so strong and persistent in the face of all the shear.  If the shear can simmer down this will strengthen fast - if poleward outflow can be established this will strengthen REALLY fast.

[Superstorm93]

[Snowlover11]

Had a brief but moderate shower pass here in white plains.

[Superstorm93]

[wthrmn654]

Recon flight

[Superstorm93]

Recon flight

...has been finished for a while. 

[wthrmn654]

Really? Need to brush up on my times

...has been finished for a while.

[tdp146]

Wow. That is pretty impressive then. Gotta think there will be changes tonight in the modeling as I don't think any models had this thing at 990 by this point.  Anyone know if the 18Z suite will have the recon data digested?

From pecking around other sites, I believe it will be the 0z suite that has the recon data. 

[Hoth]

 The equatorward outflow from Joaquin is amazingly good - its remarkably well-ventilated for such a sheared storm.  That (and the bathtub SSTs) is why the convection is so strong and persistent in the face of all the shear.  If the shear can simmer down this will strengthen fast - if poleward outflow can be established this will strengthen REALLY fast.

Establishing an anticyclone to the north would really help with that. Perhaps tomorrow?

[wthrmn654]

Last Updated: 9/29/2015, 5:00:00 PM (EDT)

Location: 26.0N 71.0WMovement: WSW at 5 mphWind: 65 MPHPressure: 990 MB

[IsentropicLift]

Wow that is impressive, and honestly a bit higher than I was expecting. Going to be some major flooding in the hardest hit areas.

[wthrmn654]

The ensemble spread is insane!

[Blizzard-on-GFS]

The million dollar question is does this system ultimately escape offshore or does it curve west?

[wthrmn654]

The cloud pattern of the storm has become better organized during

the day, with the low level center now embedded inside the northern

edge of the main area of deep convection. Animation of cirrus

motions suggest that upper-level outflow is becoming a little more

prominent over the northern portion of the circulation, and this is

consistent with decreasing northerly shear. Flight-level,

dropsonde, and SFMR wind observations from an Air Force

reconnaissance aircraft indicate that Joaquin has strengthened and

the intensity is now estimated to be 55 kt. With a more favorable

upper-level wind environment now expected to prevail, the official

forecast calls for more strengthening than the previous advisories.

Joaquin is expected to become a hurricane within 24 hours, with

additional intensification likely thereafter. The NHC intensity

forecast is similar to the latest SHIPS model output.

Fixes from the aircraft show a southward component of motion and

the initial motion estimate is now 240/4 kt. Joaquin is currently

south of the southwestern periphery of a weak mid-level ridge. The

ECMWF model shows this ridging to the north of the tropical cyclone

to be more prominent over the next few days than the other dynamical

models. Consequently, the ECMWF takes Joaquin more to the

west and southwest through 72 hours than any of the other available

guidance. Later in the forecast period, there is a significant

divergence in the track guidance. The HWRF and U.K. Met office

models forecast Joaquin to move over the East Coast of the United

States later in the period whereas the ECMWF and GFS keep the system

well offshore. The official forecast lies between these

possibilities and is similar to the latest Florida State University

superensemble solution.

Interests in the Bahamas should monitor the progress of this storm.

Watches or warnings may be issued for portions of these islands

later this evening.

Forecast positions and Max winds

Init 29/2100z 26.0n 71.0w 55 kt 65 mph

12h 30/0600z 25.8n 71.6w 60 kt 70 mph

24h 30/1800z 25.5n 72.5w 65 kt 75 mph

36h 01/0600z 25.1n 73.3w 70 kt 80 mph

48h 01/1800z 24.8n 73.9w 75 kt 85 mph

72h 02/1800z 25.0n 74.0w 80 kt 90 mph

96h 03/1800z 29.0n 73.0w 80 kt 90 mph

120h 04/1800z 34.0n 71.0w 75 kt 85 mph

$$

forecaster Pasch

[dmillz25]

Joaquin looks to hit cat 1 at least later on

[Superstorm93]

I'd be shocked if it wasn't a hurricane tomorrow morning.

Sent from my SM-G925V using Tapatalk

[snywx]

71f w/ Lgt Rain

 

0.11" of rain 

[IsentropicLift]

That's a ton of rain on the DCA radar and to be completely honest, it looks a lot further southeast than the 12z guidance model consensus

 

http://radar.weather.gov/radar.php?product=NCR&rid=lwx&loop=yes

[IsentropicLift]

I thought this post from the main forum was to good not to pass on. I have to admit, it does sound awfully ominous

 

 

Once the low-level and mid-level centers become fully aligned, I truly believe that Joaquin will likely intensify faster than forecast. By days two and three, the storm will be wedged between a developing cutoff low over the Southeast and a cold mid-level trough over ex-Ida to its east. Such an environment is not only conditionally unstable, favoring rapid convective growth, but also, with a blocking high to the north, conducive to low ambient pressures as well as upper-level divergence.

This environment, filled with ample low-level moisture and high precipitable water, would support the development of dual outflow channels in the south and north quadrants of Joaquin, especially as the cutoff low becomes negatively tilted by day four and beyond. As Joaquin interacts with the trough, it may maintain its intensity or deepen even further on day four, thanks to some indirect baroclinic influences, as the storm initially parallels the mean shear vector.

Already, Joaquin is clearly organizing even though the centers are not yet fully aligned. The storm is clearly intensifying faster than originally expected, and even the deterministic ECMWF is likely underestimating the rate of deepening, showing 990 mb by 12Z tomorrow, even though the pressure is already down to that level. An excellent outflow channel is already established in the southern quadrant, and the nascent CDO is slowly expanding westward as northerly shear lessens.

Based on all indications, significant, quite possibly rapid intensification will commence tomorrow, as an upper-level anticyclone builds over the system. Thus, Joaquin will likely have about four full days (Wednesday through Saturday) to intensify significantly. The stronger intensity in the short term would likely bring the cyclone into the east-central Bahamas in little more than two days, with the deeper system enhancing mid-level heights to its north. The ECMWF ensembles have consistently shown this.

Given all indications and trends, I would not be surprised if Joaquin becomes a significant hurricane (85+ kt) as it meanders over the east-central Bahamas on Thursday and Friday. A potentially severe impact to the Bahamas (Eleuthera, Cat Island, San Salvador, and possibly even the Exumas) is becoming more plausible. The 1929 Bahamas hurricane underwent rapid deepening in a similar set-up; Joaquin may well follow its example, only farther east.