Tracking the Tropics:

[Andrew]

But it has to clear Florida first if I read the models right. I had a gut feeling that people on the E Gulf Coast (at least) would be the ones to have to really watch it.

Right now everyone needs to keep an eye on it but don't worry too much about it. There are a lot of questions to be answered and few solutions. Hopefully by the middle of the week we have a better idea of what will happen.

May I please share a personal landfall guess (big G) with you?

Haha, go ahead.

[Skyguy]

Right now everyone needs to keep an eye on it but don't worry too much about it. There are a lot of questions to be answered and few solutions. Hopefully by the middle of the week we have a better idea of what will happen.

May I please share a personal landfall guess (big G) with you?[/quote]

Haha, go ahead.[/quote]

Well, I've been studying the edge of the high pressure ridge that expected to move NE. Now, IF the ridge holds configuration by the time 99L organizes, and IF the storm rides the edge of the ridge, like they're supposed to, my guess would be that we're looking at a landfall in New Iberia, LA.

Remember, I'm just guessing based on charts I've been looking at. I'm not forecasting. BUT---could I be on to something?

[Andrew]

Right now everyone needs to keep an eye on it but don't worry too much about it. There are a lot of questions to be answered and few solutions. Hopefully by the middle of the week we have a better idea of what will happen.

May I please share a personal landfall guess (big G) with you?

Haha, go ahead.[/quote]

Well, I've been studying the edge of the high pressure ridge that expected to move NE. Now, IF the ridge holds configuration by the time 99L organizes, and IF the storm rides the edge of the ridge, like they're supposed to, my guess would be that we're looking at a landfall in New Iberia, LA.

Remember, I'm just guessing based on charts I've been looking at. I'm not forecasting. BUT---could I be on to something?[/quote]


That is a pretty far west guess/prediction. You will need a stronger ridge and longer lasting for that to happen. We will see what the ECMWF outputs tonight.

[worrybug]

Right now everyone needs to keep an eye on it but don't worry too much about it. There are a lot of questions to be answered and few solutions. Hopefully by the middle of the week we have a better idea of what will happen.

May I please share a personal landfall guess (big G) with you?

Haha, go ahead.

Well, I've been studying the edge of the high pressure ridge that expected to move NE. Now, IF the ridge holds configuration by the time 99L organizes, and IF the storm rides the edge of the ridge, like they're supposed to, my guess would be that we're looking at a landfall in New Iberia, LA.

Remember, I'm just guessing based on charts I've been looking at. I'm not forecasting. BUT---could I be on to something?[/quote]


That is a pretty far west guess/prediction. You will need a stronger ridge and longer lasting for that to happen. We will see what the ECMWF outputs tonight.[/quote]


Uh, Andrew.....

[Andrew]

GFS still shows little development while the ECMWF is keeping on track with development and a florida landfall. Still looks like strong riding over the east coast but this time further north and east. This would allow for a eastern gulf landfall.

[srainhoutx]

Not seeing a great deal of change in the synoptic upper air charts at 500mb suggesting a strong blocking Ridge across the Mid Atlantic/SE United States. The morning 7 Day Quantitative Precipitation Forecasts also suggest rainfall chances across the Southern Florida Peninsula are rather high as potential Hermine tracks across S Florida and enters the Gulf. RECON is en route to investigate 99L this morning flying out of St Croix.

[srainhoutx]

Reconnaissance schedule including a High Altitude Synoptic Mission by the Global Hawk to sample the upper air patterns that will finally assist in future computer guidance output for 99L and Gaston.

Code: Select all

WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1030 AM EDT TUE 23 AUGUST 2016
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
         VALID 24/1100Z TO 25/1100Z AUGUST 2016
         TCPOD NUMBER.....16-089

I.  ATLANTIC REQUIREMENTS
    1. SUSPECT AREA 
       FLIGHT ONE - TEAL 70           
       A. 24/2330Z,25/0530Z
       B. AFXXX 0408A CYCLONE
       C. 24/2230Z
       D. 19.7N 66.4W
       E. 24/2300Z TO 25/0530Z
       F. SFC TO 10,000 

       FLIGHT TWO - TEAL 71
       A. 25/1130Z,1730Z
       B. AFXXX 0508A CYCLONE
       C. 25/1000Z
       D. 21.2N 69.1W
       E. 25/1100Z TO 25/1730Z
       F. SFC TO 15,000 FT

    2. SUCCEEDING DAY OUTLOOK: 
       A. CONTINUE 6-HRLY FIXES IF SYSTEM DEVELOPS.
       B. A WC-130 SYNOPTIC SURVEILLANCE MISSION FOR 26/0000Z.

    3. REMARKS: THE GLOBAL HAWK (NASA 872) IS PLANNING A 24 HOUR
       RESEARCH MISSION AROUND TROPICAL STORM GASTON. DEPARTURE
       24/1000Z. ALTITUDE 55,000 TO 65,000 FT. 86 DROPS.

[srainhoutx]

Fiona has degenerated to Post Tropical remnant low...

POST-TROPICAL CYCLONE FIONA DISCUSSION NUMBER 27
NWS NATIONAL HURRICANE CENTER MIAMI FL AL062016
1100 AM AST TUE AUG 23 2016

Satellite images indicate that Fiona has lost even more
organization this morning with only a weak, elongated circulation
and no organized deep convection. Thus, Fiona no longer meets the
requirements of a tropical cyclone and this is the last advisory.
The initial wind speed is reduced to 25 kt in accordance with the
latest Dvorak estimates. While wind shear is forecast to decrease,
the low's structure has lost so much organization that it is not
likely to take advantage of the more conducive conditions. In
addition, dry mid-level air near the circulation is likely to limit
any organized convection. Thus regeneration is not expected at this
time. The low should move northwestward into a break in the
subtropical ridge, then westward as the ridge restrengthens.

FORECAST POSITIONS AND MAX WINDS

INIT 23/1500Z 26.1N 64.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
12H 24/0000Z 26.6N 66.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
24H 24/1200Z 27.5N 67.8W 20 KT 25 MPH...POST-TROP/REMNT LOW
36H 25/0000Z 28.4N 69.1W 20 KT 25 MPH...POST-TROP/REMNT LOW
48H 25/1200Z 29.0N 69.9W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 26/1200Z 29.5N 71.5W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 27/1200Z...DISSIPATED

$$
Forecaster Blake

[srainhoutx]

Tuesday morning Tropical briefing from Jeff:

Tropical Storm Gaston:
The strong tropical wave over the far eastern Atlantic was upgraded to a tropical depression yesterday afternoon and then to TS Gaston. Latest visible images show a well defined tropical cyclone with a deep convection over the low level center and even a times a ill defined eye-like feature. Satellite intensities are around 55kts and Gaston is well on its way to becoming a hurricane within the next 12-24 hours.

Track:
Gaston is south of the sub-tropical ridge over the eastern Atlantic and will move toward the west-northwest over the next 24 hours. A large and significant break in this ridge is noted over the central Atlantic and as Gaston reaches the western edge of the ridge he will slow and turn toward the NW and N over the open Atlantic.

Intensity:
Gaston is under favorable conditions for the next 48 hours for development with light wind shear aloft and warm sea surface temperatures. The model consensus and official hurricane center forecast brings Gaston to a 100mph category 2 hurricane before conditions…mainly increased upper level WSW shear and drier air possibly result in some weakening.

Note: NASA is planning a 24-hr research mission around Gaston with the global hawk aircraft to drop 86 sondes.

99L:

The large tropical wave located a few hundred miles E of the Leeward Islands has shown an increase in organization overnight with moderate to at times heavy convection developing in an near the wave axis. There has yet to be defined low level circulation shown on visible images…however a USAF mission is currently planned for this morning to investigate this system and its structure.

While near term development chances appear on the lower side, the system will track WNW toward the Bahamas by this weekend where conditions may be much more favorable for development. There continues to be significantly different solutions offered by both the global and hurricane models with respect to both the track and intensity of the system as it nears FL late this weekend. This inconsistency is resulting in less than average confidence on what will actually happen.

What seems to be agreed upon by all the models is that a fairly strong high pressure ridge will be developing over the SE US and mid Atlantic states this weekend into early next week which will result in a slowing of this feature over the Bahamas and potentially a turn toward the W or even WSW. Much of this left turn depends on how large and intensity of the ridging over the SE US. Model ensembles have been a bit more consistent than the operational runs on this general pattern of a WNW/NW moving system slowing and turning toward the W.

As for intensity…it is all over the place with the EURO and HWRF by far the strongest and the CMC and UKMET on the weaker side while the GFS shows no development at all. Ensembles are also leaning toward the weaker solutions especially when compared to the HWRF.

This is a good time to remind everyone that following every run of each model and its exact track is not the best forecast approach…but instead use the longer range guidance for upper air steering patterns…the placement of trough and ridges and any trends in the guidance clustering or ensembles.

NHC gives this wave a 60% chance of development over the next 5 days.

Aircraft: NHC has tasked 2 additional recon missions tomorrow and Thursday and a synoptic scale WC-130 mission Thursday evening.

[srainhoutx]

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT TUE AUG 23 2016

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

The National Hurricane Center has issued the last advisory on
Tropical Depression Fiona, located several hundred miles north of
the Leeward Islands, and continues to write advisories on Tropical
Storm Gaston, located several hundred miles west of the Cabo Verde
Islands.

Reports from an Air Force Reserve Hurricane Hunter aircraft indicate
that the tropical wave located a few hundred miles east of the
Lesser Antilles has an elongated and poorly defined circulation. In
addition, satellite imagery indicates that the associated shower and
thunderstorm activity remains disorganized. Environmental conditions
are only marginally conducive for development during the next couple
of days while the system moves west-northwestward at 15 to 20 mph
near the northern Leeward Islands and the Greater Antilles. Large-
scale conditions could become more conducive later this week while
the system moves nears the southeastern and central Bahamas. Another
Air Force Reserve Hurricane Hunter aircraft is scheduled to
investigate this disturbance tomorrow, if necessary. Interests from
the islands of the northeastern Caribbean Sea to the Bahamas should
continue to monitor the progress of this system. Gusty winds, heavy
rains, and possible flash floods and mud slides could occur over
portions of these areas regardless of tropical cyclone formation.
Please consult products issued by your local meteorological offices
for further details.
* Formation chance through 48 hours...medium...40 percent
* Formation chance through 5 days...medium...60 percent

[Andrew]

Latest ECMWF is a lot more aggressive in development and I am fairly confident this will be a gulf coast storm. While all locations should keep an eye on the storm, With that said for now I do believe this will stay a central/east coast storm. Ridging is forecasted to breakdown late next week and is forecasted to be more northeast. That would allow for the storm to rotate around the ridge sooner than later. Of course models are still adjusting at a pretty large rate so it will be a wait and see thing.

[Rip76]

You beat me to it on the thoughts about this.

[srainhoutx]

It appears to me that TC Genesis may well be developing. The latest visible imagery suggests a more consolidate low level circulation may be organizing near 16N 58W.

[Andrew]

It appears to me that TC Genesis may well be developing. The latest visible imagery suggests a more consolidate low level circulation may be organizing near 16N 58W.

Yea I have been monitoring this too. Further south than models are indicating. It will be nice once we get recon out there.

[Andrew]

ECMWF ensemble are rather supportive of a gulf entry also. I suspect we will see the GFS trend this way too over the next couple days.

[unome]

Gaston track shifts west

http://www.nhc.noaa.gov/#GASTON

Beyond 3 days, a break in the subtropical ridge is forecast, although the models are not in great agreement on exactly what longitude Gaston reaches before its likely recurvature. Overall, the model guidance has shifted a bit westward, and the latest NHC track forecast is shifted in that direction.

[Rip76]

Interesting couple of days ahead.

[srainhoutx]

12Z ECMWF Ensembles do raise an eyebrow. The individual members are beginning to trend left of the Operational suggesting a stronger SE Ridge and a more Westerly track may be possible after future Hermine crosses S Florida.

[Andrew]

18z GFS is already coming in stronger but initialization was probably a little too far to the northwest (based on satellite data), not that it will make much of a difference.

Edit to add, much further west on this one. Stronger ridging.

gfs_z850_vort_watl_6.png

gfs_z850_vort_watl_17.png

gfs_z850_vort_eus_20.png

gfs_z850_vort_eus_25.png

[Scott747]

Yeah 18z does start to get ones attention. I'll stand by waiting till 99l/Hermine is near Puerto Rico before getting more interested, but if modeling continues to show ridging building on holding strong further west....