Atlantic Tropical Action 2014

[GaWx]

Just like that, this is now Invest 92-L.

[Superstorm93]

No change...

 

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT WED SEP 10 2014

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Shower activity associated with a broad area of low pressure located
about 600 miles west of the Cape Verde Islands remains disorganized.
While tropical cyclone formation is not anticipated today,
environmental conditions could become somewhat more favorable for
development by later in the week while the low moves toward the
west-northwest and northwest at about 15 mph over the open Atlantic.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...high...70 percent.

Disorganized cloudiness and showers over the Bahamas and the
adjacent Atlantic are associated with a weak surface trough
interacting with an upper-level low. Development, if any, of this
system is expected to be slow to occur while it moves generally
westward at 5 to 10 mph during the next few days.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...low...20 percent.

 

 

[Kory]

They probably want some more model support besides the GEM before they raise development chances.

[wxmx]

At least in the short term, it will move west or even a bit WSW, as there is a ridge to the N and NW. It also looks pretty small, so rapid development into a TS is not out of the question.

[wxmx]

It appears there is little chance of a trough eroding the SE ridge, not even in the CMC forecasts. The reason the CMC tracks this to the Nern GoM is that ridge is a little weaker and gets pushed a bit south, leaving 92L very near the axis ridge. The GFS, Euro and their ensembles keep 92L below the axis ridge and in a track farther to the left.

[wxmx]

ASCAT confirms there's a weak closed surface low (not that it needed much confirmation, as vis imagery is pretty telling). The passes were at 14:33 and 15:25 UTC...with the latter showing stronger winds in the NW quad, where convection has been developing. This pretty much matches up with trends in the satellite imagery at those times...and probably is better organized and strengthening now. Shear is pretty low, so I guess the convection won't just go away...so I'll venture a guess that we'll have at least a mandarin by the next TWO.

[MarkSC]

Are we too wedded to the models? Other than the lack of model support, which is admittedly cause for concern, 92L has a lot going for it. It's over one of the best spots in the entire Atlantic basis for development currently. 

[wxmx]

Are we too wedded to the models? Other than the lack of model support, which is admittedly cause for concern, 92L has a lot going for it. It's over one of the best spots in the entire Atlantic basis for development currently. 

I wouldn't blame it entirely on the models. 92L is tiny, so there is probably some resolution issues as well.

 

Outflow boundaries ejected from the mess in the NW Caribbean are approaching 92L from the SW, it will be interesting to see if there's an interaction and if they would help increase the convection over the disturbance.

[MarkSC]

The early BAM models seem to agree with GEM on the track (north central Gulf and then a hard right turn in about 5 days). 

[IsentropicLift]

The early BAM models seem to agree with GEM on the track (north central Gulf and then a hard right turn in about 5 days). 

 

[Guest Imperator]

Are we too wedded to the models?

 

I think this is definitely a problem, especially among hobbyists who don't have much meteorology knowledge and even worse, among some "social" meteorologists.  As I said a couple of weeks ago in this thread, putting so much raw model output out there in the hands of a hobbyist with little or no professional training is dangerous. You can see some of that result on social media these days.

[wxtrackercody]

Talk about quick organization. It was a bare swirl just a few hours ago.

 

Sea surface temperatures are very warm and shear is low, so I wouldn't be surprised to see this become a tropical cyclone before moving into Florida.

 

[Weather.St]

Talk about quick organization. It was a bare swirl just a few hours ago.

 

Sea surface temperatures are very warm and shear is low, so I wouldn't be surprised to see this become a tropical cyclone before moving into Florida.

 

My thoughts exactly. Convection is persisting very well over the closed low. I wouldnt be surprised to see TD status on this very shortly.

[Kory]

This thing is going to be a slow mover.  Nothing to really inhibit slow intensification but maybe some northerly shear from the ridge over the Southeast U.S.  It's got about 48 hours over water before hitting South Florida and the Gulf Stream runs right along the coast there...just something to keep in mind.  

[Srain]

The Gulf Coast WFO's in their afternoon coordination call are not enthusiastic regarding any development from 92L. The general consensus is this feature will move W into the Gulf as an open wave/trough and enhance precipitation across the Northern and NW Gulf as a stalled frontal boundary lingers inland or along the Gulf Coast. The Euro/GFS solutions seem reasonable and suggest this disturbance will move W and near the NE Mexico/South Texas Coast in about 6-7 days.

[ineedsnow]

Wow looking much better now maybe I was wrong this morning when I said there was no chance lol

[Superstorm93]

While 92L is looking rather interesting this afternoon, we still have zero support from any reliable global models as well as the intensity models. 92L is rather small and pressures are very high in the area (on the order of 1017mb or so) so I have a really hard time believing that convection will be able to hold on long enough for this to actually be able to consolidate the surface low to a point that this takes advantage of the highly favorable OHC/thermo environment.

 

The "2014 Rule" is definitely in effect for this one:

 

[hurricaneman]

Looks like there are multiple vortmaxes movving around the main center in the convection

[Kory]

Recon is going in tomorrow afternoon.  

[GaWx]

While 92L is looking rather interesting this afternoon, we still have zero support from any reliable global models as well as the intensity models. 92L is rather small and pressures are very high in the area (on the order of 1017mb or so) so I have a really hard time believing that convection will be able to hold on long enough for this to actually be able to consolidate the surface low to a point that this takes advantage of the highly favorable OHC/thermo

The reliable models are probably having trouble developing this because of its small size. From the looks of things, they may be falling behind what appears may already be occurring, an organizing LLC/developing TC underneath upper level high pressure over very warm SST's and within a moist environment. Keep watching this one. The small size in combo with the overall current good conditions could allow for some rather quick development even while still E of FL.

Edit: Is the NAM from yesterday going to score a win??

[Big O]

The Gulf Coast WFO's in their afternoon coordination call are not enthusiastic regarding any development from 92L. The general consensus is this feature will move W into the Gulf as an open wave/trough and enhance precipitation across the Northern and NW Gulf as a stalled frontal boundary lingers inland or along the Gulf Coast. The Euro/GFS solutions seem reasonable and suggest this disturbance will move W and near the NE Mexico/South Texas Coast in about 6-7 days.

Our friend from down south agrees with your assessment on track (not necessarily on intensity)  

[wxmeddler]

The upper level winds on the backside of the huge upper level ridge over the SE US is going to put some marginal to strong (20-30kts) over 92L in about 24 hrs. It has until then to get it's act together. Maybe if it gets going quick it can make it to TD/Low-end TS but after that window is closed, it's development is going to be stunted.

[Superstorm93]

000

ABNT20 KNHC 102330

TWOAT

TROPICAL WEATHER OUTLOOK

NWS NATIONAL HURRICANE CENTER MIAMI FL

800 PM EDT WED SEP 10 2014

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Satellite images indicate that the shower activity associated

with a broad area of low pressure centered about 650 miles west of

the Cape Verde Islands has increased and become a little better

organized this evening. This system is now moving toward an area

more favorable for development, and a tropical depression could form

during the next day or two while the low moves toward the

west-northwest and northwest at about 15 mph over the open Atlantic.

* Formation chance through 48 hours...medium...40 percent.

* Formation chance through 5 days...high...70 percent.

A weak area of low pressure has formed near the northwestern

Bahamas, and its associated shower activity is showing some signs of

organization. However, the environment is forecast to become

unfavorable for significant development while the low moves slowly

westward toward southern Florida. If necessary, an Air Force plane

will investigate this system tomorrow. Regardless of development,

this low will bring heavy rains over portions of southern Florida

and the Florida Keys during the next couple of days.

* Formation chance through 48 hours...low...20 percent.

* Formation chance through 5 days...medium...30 percent.

[Superstorm93]

Recon is going in tomorrow afternoon.  

 

Not exactly. It's one of those "if necessary" deals. 

[David Reimer]

WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
0530 PM EDT WED 10 SEPTEMBER 2014
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 11/1100Z TO 12/1100Z SEPTEMBER 2014
TCPOD NUMBER.....14-102 AMENDMENT

I. ATLANTIC REQUIREMENTS...ADDED
1. SUSPECT AREA (NEAR BAHAMAS)
FLIGHT ONE -- TEAL 71
A. 11/1730Z
B. AFXXX 01HHA INVEST
C. 11/1445Z
D. 27.0N 77.5W
E. 11/1700Z TO 11/2200Z
F. SFC TO 10,000FT

FLIGHT TWO - TEAL 72
A. 12/0530Z, 1130Z
B. AFXXX 0206A CYCLONE
C. 12/0215Z
D. 27.0N 78.5W
E. 12/0500Z TO 12/1130Z
F. SFC TO 10,000FT

2. OUTLOOK FOR SUCCEEDING DAY.....CONTINUE 6-HRLY
FIXES IF SYSTEM DEVELOPS AND REMAINS OFFSHORE.
3. REMARKS: NASA 872 RESEARCH FLIGHT AT 12/2200Z.

[wxmx]

The upper level winds on the backside of the huge upper level ridge over the SE US is going to put some marginal to strong (20-30kts) over 92L in about 24 hrs. It has until then to get it's act together. Maybe if it gets going quick it can make it to TD/Low-end TS but after that window is closed, it's development is going to be stunted.

That's right...although a deeper system would feel a little less shear, as it would probably be moving faster in the mid/upper level steering currents...anyway, like you said it has 24-48 hrs to organize in a relatively low shear environment.

[GaWx]

That's right...although a deeper system would feel a little less shear, as it would probably be moving faster in the mid/upper level steering currents...anyway, like you said it has 24-48 hrs to organize in a relatively low shear environment.

 

 Looking at infrared satellite photos this evening, I see renewed healthy convection as older dies out. I'm now thinking 2/3 chance of a TD+ while still E of FL due to current conditions being so favorable (well organized with small size/good moisture/high SST's/upper high/light shear/far enough from land since Bahamas don't interfere much).  Anyone disagree?

 

 Edit: Another way to put this: how much more favorable a combo of factors can there be? Are the overall factors as favorable as they seem to me?

[Superstorm93]

 

 

Philip Klotzbach‏@philklotzbach·9 mins 

New two-week Atlantic basin hurricane forecast issued. More below-average activity predicted

 

http://tropical.atmos.colostate.edu/Includes/Documents/Two_Week_Forecasts/september_11_2014.pdf

[icebreaker5221]

 Looking at infrared satellite photos this evening, I see renewed healthy convection as older dies out. I'm now thinking 2/3 chance of a TD+ while still E of FL due to current conditions being so favorable (well organized with small size/good moisture/high SST's/upper high/light shear/far enough from land since Bahamas don't interfere much).  Anyone disagree?

 

 Edit: Another way to put this: how much more favorable a combo of factors can there be? Are the overall factors as favorable as they seem to me?

 

I agree that the environment 92L is presently in is quite good.  However, shear has been increasing steadily just 100-200 km to its north, and there's also some subsidence in the area.  The fact that it's such a small system will make it more vulnerable to a deterioration of its environment.  I'd say it's best chance is if it begins drifting southward overnight.  A track along the lines of the NAM would probably be ideal. 

[wxmeddler]