Atlantic Tropical Action 2013

[Mike.Ventrice]

 

Ensemble GFS Phase Diagram

mjo july 6th.gif

 

 

Guys,

 

The GFS has been doing a very poor job with correctly representing this MJO event over the Atlantic. It's having big time problems with taking the eastward propagating MJO signal and continuing it eastward in the forecast. Instead, it's overamplifying a westward propagating response- don't trust these dynamical-model derived MJO forecasts!! They are not representative of the true state in the tropics and often struggle with MJO/CCKWs moving over landmasses such as S. America, Africa, or the Maritime Continent.

 

 

Verification of GFS forecasts are BAD:

1 WEEK: 

 

2 WEEKS:

[Mike.Ventrice]

Interesting evolution with 94l over the past few hours.. I'm thinking we might see a flight get scheduled soon...

 

[wxmx]

95L is improving it's organization quite fast. Models dont develop it until the eastern Caribbean, but it looks like there's a good chance this could become a TD sooner than that.

[GaWx]

I did a more accurate MJO phase by phase normalization based on number of July days in each phase 1995-2012:

 

July 1995-2012 # of days MJO:

 

1: 103

2: 68

3: 24

4: 26

5: 23

6: 30

7: 34

8: 37

C: 213

All: 558

 

July 1995-2012 # of TC geneses (incl. TD's) MJO:

 

1: 3
2: 8
3: 3
4: 5
5: 0
6: 2
7: 1
8: 2
C: 11

All: 35

 

# of geneses/days (July 1995-2012)(%):

 

1: 3

*2: 12

3: 13

4: 19

5: 0

6: 7

7: 3

8: 5

C: 5

All: 6

 

* current phase

 

- Per phase 2 stats for July since 1995, a 5-6 day period in phase 2 (which the GFS ens. predicts fwiw) would give ~50% chance for a TD to form then. Remember this is only July..so that is pretty impressive. Compare that 5-6 days to ~16 days for the nonactive phases for July.

- Note how much phases 2-4 dominate and note the fourfold increase from phase 1 to phase 2

- Phases 2-4 make up only ~1/5 of all July days but have yielded nearly half of all July TC's

- Phases 2-4 genesis rates/day are ~3 times that for the average of all of the other phases in July!

 

 

 The July phase 2 TC geneses include these H's since 1995 (all five hit the US as H's):

 

1995: H Erin

1996: H Bertha

2003: H Claudette

2005: H's Cindy and Dennis

[Superstorm93]

95L is improving it's organization quite fast. Models dont develop it until the eastern Caribbean, but it looks like there's a good chance this could become a TD sooner than that.

 

I'm interested to hear what the NHC thinks of it, but yeah it really has improved in organization today quite quickly. The mid-low level clouds are really telling of something at least trying to organize under the convection, but this thing is literally in the middle of the MDR still with 28-29C waters and low shear for the next 72 hours, so we have days to watch this one.

 

It would be nice to have model support though. 

 

 

 

 

 

I did a more accurate MJO phase by phase normalization based on number of July days in each phase 1995-2012:

 

I really like what you're doing with this stuff!

 

Here's the ECMWF (and its ensembles) MJO forecast, which also keeps us in Phase 2 for a while. Like Mike V. said though, the models have been less than "acceptable" with their margin of error. 

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ECMF_phase_51m_full.gif

[phil882]

95L is improving it's organization quite fast. Models dont develop it until the eastern Caribbean, but it looks like there's a good chance this could become a TD sooner than that.

The way the convective organization has hung together during the diurnal minimum has been pretty impressive. I'm still a little worried what happens as it gains latitude and accelerates in the low-level flow away from the ITCZ, but conditions should remain favorable up to 50W.

[Superstorm93]

NOUS42 KNHC 061709
REPRPD
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
0115 PM EDT SAT 06 JULY 2013
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 07/1100Z TO 08/1100Z JULY 2013
TCPOD NUMBER.....13-036 AMENDMENT

I. ATLANTIC REQUIREMENTS....................................AD DED.
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.
3. ADDITIONAL DAY OUTLOOK: POSSIBLE LOW-LEVEL INVEST
IN CENTRAL ATLANTIC NEAR 13.3N 57.3W FOR 09/1200Z.

[Superstorm93]

The NHC is already running their  track based on SHIPS/GFS conditions. 

 

Next 72 hours look good. 

 *   ATLANTIC SHIPS INTENSITY FORECAST       *
                    * GOES AVAILABLE,       OHC AVAILABLE       *
                    *      INVEST  AL952013  07/06/13  18 UTC   *

TIME (HR)          0     6    12    18    24    36    48    60    72    84    96   108   120
V (KT) NO LAND    25    28    31    35    39    49    58    65    69    71    73    75    74
V (KT) LAND       25    28    31    35    39    49    58    65    69    71    73    75    74
V (KT) LGE mod    25    26    28    30    33    41    50    60    68    72    71    67    61
Storm Type      TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP

SHEAR (KT)         9     8     9     9     9     4     7    13    19    28    30    33    36
SHEAR ADJ (KT)     5     0     1     3     3    10     5     3     5     1     0    -1     3
SHEAR DIR         30    57    56    26    25   331   348   302   304   292   302   301   300
SST (C)         28.0  27.9  27.9  27.9  27.7  27.5  27.6  27.7  28.0  28.3  28.3  28.3  28.5
POT. INT. (KT)   140   138   139   139   136   134   136   137   140   143   143   143   146
ADJ. POT. INT.   151   149   150   151   148   144   146   146   148   145   143   144   146
200 MB T (C)   -54.6 -54.8 -54.9 -54.7 -54.5 -54.7 -54.6 -54.8 -54.5 -54.7 -54.6 -54.7 -54.3
TH_E DEV (C)       6     6     7     7     7     8     9     9    11    11    12    10    11
700-500 MB RH     65    65    64    64    62    63    60    61    58    58    59    59    62
GFS VTEX (KT)      7  LOST  LOST  LOST  LOST  LOST  LOST  LOST  LOST  LOST  LOST  LOST  LOST
850 MB ENV VOR    70    70    63    59    48    37    33    16     4   -11   -13   -31   -13
200 MB DIV       -10     2    -1    -5     0    -5     8    16     9    30    42    50    60
700-850 TADV      -4    -3    -4    -7    -9    -6    -6     5    10    35    24    38    51
LAND (KM)       1346  1282  1249  1249  1151   895   741   687   390   447   244   174    78
LAT (DEG N)      7.9  xx.x  xx.x  xx.x  xx.x  xx.x  xx.x  xx.x  xx.x  xx.x  xx.x  xx.x  xx.x
LONG(DEG W)     34.5 xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x
STM SPEED (KT)    18    18    19    20    20    21    22    22    21    17    15    17    17
HEAT CONTENT      10    10    27    16    10    14    38    24    28    26    17    22    23

  FORECAST TRACK FROM OFPI      INITIAL HEADING/SPEED (DEG/KT):275/ 18      CX,CY: -17/  2
  T-12 MAX WIND:  25            PRESSURE OF STEERING LEVEL (MB):  536  (MEAN=623)
  GOES IR BRIGHTNESS TEMP. STD DEV.  50-200 KM RAD:   8.4 (MEAN=14.5)
  % GOES IR PIXELS WITH T < -20 C    50-200 KM RAD:  76.0 (MEAN=65.0)

[Alfoman]

12z CMC is on board. The wave stays disorganized until it crosses Cuba and rides along the Florida coast.

 

 

[metalicwx366]

A VIGOROUS TROPICAL WAVE IS LOCATED OVER THE EASTERN ATLANTIC ABOUT
850 MILES SOUTHWEST OF THE CAPE VERDE ISLANDS. ASSOCIATED SHOWER
AND THUNDERSTORM ACTIVITY IS SHOWING SIGNS OF IMPROVED ORGANIZATION
AND ENVIRONMENTAL CONDITIONS ARE EXPECTED TO GRADUALLY BECOME MORE
CONDUCIVE FOR DEVELOPMENT OVER THE NEXT FEW DAYS. THIS SYSTEM HAS A
MEDIUM CHANCE...30 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING
THE NEXT 48 HOURS AS IT MOVES WESTWARD AT 20 TO 25 MPH.

[HurricaneFrances04]

The Canadian solution reminds me of Charley, track then bombing off the west coast of Florida (jeez...the Canadian rapidly intensifying a storm in the eastern GOM...what's new?). 

[GaWx]

I really like what you're doing with this stuff!

 

Here's the ECMWF (and its ensembles) MJO forecast, which also keeps us in Phase 2 for a while. Like Mike V. said though, the models have been less than "acceptable" with their margin of error. 

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ECMF_phase_51m_full.gif

 

Thanks. Mike's point about the model errors is important to consider and shouldn't be ignored. Nevertheless, we're now in phase 2 and all of the members of both the GFS and Euro ens. agree on at least several more days of phase 2 as you said. So, unless there is a major failure here, phase 2 for the next few days looks to continue. We'll see.

 

 Going on the assumption of several more days of phase 2, consider this:

 

- There have been 8 CONUS H hits from July geneses since 1995. Of these, 5 were phase 2 geneses. The other three were phase 3, phase 4, and circle.

- The 8 genesis dates for these 8 US H hits: 7/3, 7/5, 7/5, 7/8, 7/16, 7/20, 7/31, 7/31. The four pre 7/16 geneses were all from phase 2. Coincidence? Perhaps, considering the small sample. However, I still think that it is interesting that CONUS hasn't been hit by a H that had its genesis in other phases prior to 7/16 since the start of the warm AMO. Will there be a fifth in a row early this month? We're in early July, there is an impressive dist. out there, no clearcut recurvature is yet indicated, and we're in phase 2. Maybe enough reason for somewhat elevated July threat of a H hit to the US from this dist.?

[Ed Lizard]

As unimpressively as GFS initializes it, still brings a decent disturbance to the shores of Hispaniola...

[bluewave]

As unimpressively as GFS initializes it, still brings a decent disturbance to the shores of Hispaniola...

 

The Euro maintains it as an identifiable feature all the way over to the SE with enhanced rainfall as it interacts with a trough in the East.

[Alfoman]

95L seems like it is definitely spinning as the currently 1009 mb low strengthens slowly as the system races at 20-25 mph westward. That westward motion will likely translate into a WNW motion tomorrow and monday as 95L makes it toward the Lesser Antilles. However, getting there might not be so easy. Even though most of the dry air is north of the system, as it moves north- some of the dry air above the trade wind inversion might harm the circulation as it parts ways with the ITCZ that's currently enhancing convergence. Also over the islands there is currently 10/15+ knots of wind shear that could definitely slow any convective growth as the system makes its way into the Caribbean.   However, there is an even bigger problem for the system, which will be the fact that it is going to be embedded in a fast trade wind flow north of 10N as the High pressure strengthens in the central Atlantic. The trade wind belt will cause the system to move at high speeds 15 mph+ which will really make it hard for 95L to organize and close off a low level circulation. BUT as 95L makes its way to cuba and the gulf, it will get picked up by the trough and slow down considerably. Then, we will need to watch it for sure. 

 

Guys, please tell me how Im doing, cause I was always too scared to post on here. 

 

[GaWx]

95L seems like it is definitely spinning as the currently 1009 mb low strengthens slowly as the system races at 20-25 mph westward. That westward motion will likely translate into a WNW motion tomorrow and monday as 95L makes it toward the Lesser Antilles. However, getting there might not be so easy. Even though most of the dry air is north of the system, as it moves north- some of the dry air above the trade wind inversion might harm the circulation as it parts ways with the ITCZ that's currently enhancing convergence. Also over the islands there is currently 10/15+ knots of wind shear that could definitely slow any convective growth as the system makes its way into the Caribbean.   However, there is an even bigger problem for the system, which will be the fact that it is going to be embedded in a fast trade wind flow north of 10N as the High pressure strengthens in the central Atlantic. The trade wind belt will cause the system to move at high speeds 15 mph+ which will really make it hard for 95L to organize and close off a low level circulation. BUT as 95L makes its way to cuba and the gulf, it will get picked up by the trough and slow down considerably. Then, we will need to watch it for sure. 

 

Guys, please tell me how Im doing, cause I was always too scared to post on here. 

 

95L 2.jpg

 

Scared of what? Post whatever you want as long as it is relevant. You have just as much right to post as any member. Your posts have been good to me, regardless. 

 

Regarding 95L and considering MJO phase 2 July climo, it probably has a better chance in or near the Caribbean (assuming we'd still be in phase 2 then). Only one phase 2 July genesis since 1995 was east of 60W: Bertha of 1996. The others were in the Caribb, off the SE coast, and in the Gulf. So, that sort of jibes with what you're saying.

[Ed Lizard]

^^ Seems ok to me.  As a rank amateur, knowing more than a few, but a lot less than others, I know it can be intimidating to post with the red taggers and the really self educated amateurs.

 

 

Faster LL speed, besides enhancing shear, also tends to reduce surface convergence, a reason storms favor the Western Caribbean over the Eastern Caribbean as a genesis area, especially early season, the South American heat low speeds up the Easterlies, lowering convergence and raising shear, as flow slows down farther from South America, slower forward speed always means less shear (assuming upper flow is from the West) and usually implies convergence.

 

Shear does look like an issue as it approaches Lesser Antilles, if it stays South, as 18Z GFS sort of suggests, it'll miss the worst of the shear and the 850 mb flow doesn't look that horribly fast.

 

GFS kills it after this, perhaps land interaction.  I don't know for sure.  Looks like a smidge of Southerly shear, and anything that hits Hispaniola when conditions aren't absolutely perfect to begin with will often poof.

 

Sort of OT

 

12Z GFS sees another decent disturbance before the wave number truncation, and 12Z Euro has a wave exiting Africa at fairly high latitude, but looking good and maybe heading a smidge South of due West.

 

[Ed Lizard]

GaWx, one of my favorites, although minor- Claudette.  What was the MJO phase then?

[Superstorm93]

Windsat caught 95L 

 

Better than I expected. 

 

[GaWx]

GaWx, one of my favorites, although minor- Claudette.  What was the MJO phase then?

 

Ed,

 Claudette of 2003 formed during MJO phase 2.

[Snow_Miser]

We have a mandarin.

[Thunder Road]

We have a mandarin.

 

It was 30% at 2:00.

[N. OF PIKE]

Windsat caught 95L

Better than I expected.

mapImage.png

When was the 8pm nhc statement put together

[U_Thant]

Another consideration...(preaching to the choir here to some degree). Stronger trade flow versus weaker equatorward winds are the most ideal environmental flow for t-waves to close off.

 

Environmental

  flow with

 "Favorable"

 Deformation

W/R/T t-waves

 closing off

 

N

<--------

<------

<----

<--

EQ

 

Environmental

  flow with

  "Neutral"

(zero in Y)

 Deformation

W/R/T t-waves

 closing off

 

N

<--------

<--------

<--------

<--------

EQ

 

Environmental

  flow with

"Unfavorable"

 Deformation

W/R/T t-waves

 closing off

 

N

<--

<----

<------

<--------

EQ

 

Typically, lower latitude (<10N) t-waves/vortices encounter the most ideal environmental flow, which then become neutral and sometimes unfavorable as it detaches from, or moves farther north away from, the ITCZ. Also, net speed (mass) convergence and divergence resulting from local east-west acceleration/deceleration of the trade winds plays a major role, and that in the early-mid season, there is climatological maximum of speed divergence in the eastern Caribbean, which Shieh and Collucci showed numerically in a study a few years ago.

[Superstorm93]

^^^

 

Excellent point. 

 

95L is somewhat more organized than when the Windsat pass was completed. As long as this stays predominantly closed off by the time it reaches 55W or so, I'm starting to open up to the idea that this might eventually become a tropical storm

 

Updated at 8z

 

(OLD)

 

 

[Ed Lizard]

Looks, if anything, like it could be experiencing Easterly shear.

 

OT

 

GFDL ensembles.

 

I hadn't heard...

 

• Goal: Design and run a simple ensemble based on the operational GFDL model to provide additional real-time guidance on track and intensity.
• Method: Run at same resolution as the operational GFDL model [parent domain and 2 nests with 1/2° (~55 km), 1/6° (~18 km), and 1/12° (~9 km) horizontal grid spacing, respectively]. Apply perturbations by either modifying the vortex structure, moisture fields, or sea-surface temperatures (SSTs) in the core region, as well as by modifying the model physics.
• Resources: All forecasts run on NOAA's Jet machine at Earth System Research Laboratory (ESRL) in Boulder, CO.

[Snow_Miser]

Up to 40% at 8 AM.

[phil882]

If you look at the last few visible frames, there is some evidence there is a tighter low-level vortex (around 9.5N, 42W) that is still partially observed by the convection.

 

[Mike.Ventrice]

If you look at the last few visible frames, there is some evidence there is a tighter low-level vortex (around 9.5N, 42W) that is still partially observed by the convection.

 

uh-oh... I see a naked swirl alert... look to the north of the deep convection.. but yeah Phil, def some sort of ll vortex there

[phil882]

uh-oh... I see a naked swirl alert... look to the north of the deep convection

 

Yep... as the system continues to gain latitude its also accelerating further as the low-level flow becomes enhanced by the trades. The upper level flow is going to have a difficult time keeping up over the next few days, not unlike Ernesto the first 24 or so hours of its life.