Tracking the Tropics:

[sambucol]

I guess the flip flopping isn't done. I don't understand how this system would move north with that ridge sitting there.

[Andrew]

I guess the flip flopping isn't done. I don't understand how this system would move north with that ridge sitting there.

GFS is more organized on the 18z run, main reason it sends it northeast is the breakdown in ridging paired with a ridge that is supposed to develop right over Texas. I am a little hesitant about that though. I'm still hesitant this develops at all.

[Skyguy]

I guess the flip flopping isn't done. I don't understand how this system would move north with that ridge sitting there.

GFS is more organized on the 18z run, main reason it sends it northeast is the breakdown in ridging paired with a ridge that is supposed to develop right over Texas. I am a little hesitant about that though. I'm still hesitant this develops at all.

Our local pro mets aren't hesitant.

Chances for rain will trend down as we move deeper into the work
week. An area of high pressure will shift back into play this
upcoming Thursday. POPs will begin to approach normal climatology
again next Tuesday, with slightly lower chances of isolated
showers.

Don't you agree with them?

[unome]

animated model evolution 99L

• tracks:
  http://flhurricane.com/modelanimator.ph ... 16&storm=8
  http://flhurricane.com/clarkmodelanimat ... 16&storm=8
  
  intensity:
  http://flhurricane.com/clarkintensityan ... 16&storm=8

6AM - first light for visible http://www.ssec.wisc.edu/~rabin/goes14/loop_srso.html

[cperk]

I think I can safely speak for all my forum members in saying I hope 99L feels that weakness forecast by the models I don't wish this system on anyone ,but if it misses that weakness it could spell trouble for the central and western GOM.

[nuby3]

I guess the flip flopping isn't done. I don't understand how this system would move north with that ridge sitting there.

GFS is more organized on the 18z run, main reason it sends it northeast is the breakdown in ridging paired with a ridge that is supposed to develop right over Texas. I am a little hesitant about that though. I'm still hesitant this develops at all.

Our local pro mets aren't hesitant.

Chances for rain will trend down as we move deeper into the work
week. An area of high pressure will shift back into play this
upcoming Thursday. POPs will begin to approach normal climatology
again next Tuesday, with slightly lower chances of isolated
showers.

Don't you agree with them?

where does this say anything about development of 99l? I don't see anything about it, or any suggestion it will develop. are you referring to being hesitant about the ridging over texas being paired with a weakness in the ridge on the eastern Guld coast? or the ridging over texas alone? or the weakness over the eastern gulf coast alone?

[srainhoutx]

TROPICAL DEPRESSION EIGHT DISCUSSION NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL AL082016
1100 AM EDT SUN AUG 28 2016

The area of low pressure located west of Bermuda has been producing
intermittent organized deep convection for the last 24 hours or so,
and the convection has increased markedly since 06Z. Given this,
and the well-defined center shown by an overnight ASCAT pass,
advisories are now being initiated on this system as a tropical
cyclone. The initial intensity is estimated to be 30 kt based on
the latest Dvorak estimates of T2.0/30 kt from TAFB and SAB. An Air
Force Reserve Hurricane Hunter aircraft is scheduled to investigate
the depression this afternoon.

The environment is only expected to be marginally conducive for
intensification, with moderate southeasterly to easterly shear
expected to become southwesterly and increase further in 36 to 48
hours. As a result, only modest strengthening is shown in the
official forecast, with the depression expected to become a tropical
storm in the next day or two. After that time, the global models
show the cyclone opening up along a frontal zone well offshore of
the northeastern United States. However, there is some disagreement
in when this will occur, with the GFS showing the cyclone
dissipating in about 3 days, and the ECMWF hanging onto it until
around day 5. As a compromise, the NHC forecast shows dissipation
after day 4, but this timing is quite uncertain.

The depression is currently situated south of a mid-level ridge that
extends from the Mid-Atlantic states into the western Atlantic, and
the initial motion estimate is 280/08. The ridge is forecast to
break down and shift eastward during the next 2-3 days, which should
result in the cyclone gradually turning poleward and then recurving
during the next 72 hours. The NHC track forecast is close to a
blend of the GFS and ECMWF models through dissipation. This
forecast keeps the center of the cyclone east of the Outer Banks of
North Carolina, but a tropical storm watch may be needed for that
area later today.

Based on an evaluation of satellite imagery and data during the past
few days, it appears that the remnants of Tropical Storm Fiona are
not directly responsible for the genesis of this depression. The
Fiona remnants were absorbed into a separate area of pre-existing
vorticity, with the current depression developing out of the
combined system. As a result, this is considered to be a new
tropical cyclone, not a regeneration of a previous tropical
cyclone.

FORECAST POSITIONS AND MAX WINDS

INIT 28/1500Z 31.5N 70.0W 30 KT 35 MPH
12H 29/0000Z 32.1N 71.6W 30 KT 35 MPH
24H 29/1200Z 32.9N 73.3W 30 KT 35 MPH
36H 30/0000Z 33.6N 74.4W 35 KT 40 MPH
48H 30/1200Z 34.2N 75.0W 35 KT 40 MPH
72H 31/1200Z 36.5N 73.0W 35 KT 40 MPH
96H 01/1200Z 39.0N 66.5W 35 KT 40 MPH...POST-TROP/EXTRATROP
120H 02/1200Z...DISSIPATED

$$
Forecaster Brennan

[cperk]

nuby3 were you responding to my previous post.

[srainhoutx]

nuby3 were you responding to my previous post.

I believe that was more directed to Paul Robinson...err... I mean Skyguy / worrybug or whatever aliases he's using. But we are monitoring those posts like a hawk...

[cperk]

nuby3 were you responding to my previous post.

I believe that was more directed to Paul Robinson...err... I mean Skyguy / worrybug or whatever aliases he's using. But we are monitoring those posts like a hawk...

Thanks srainhoutx,nuby3 ignore that post now I understand why you posted that response.

[srainhoutx]

Looks like a very elongated surface low has developed with 99L ESE of Key West as it generally moves West in the mean Easterly flow. I see RECON will investigate today and it does appear the disturbance will enter the SE Gulf of Mexico sometime overnight into tomorrow.



The is a very vigorous Tropical Wave about to exit Africa that will need to be monitored this week. The models are very aggressive in developing that disturbance as it moves generally West across the Main Development Region of the Atlantic Ocean. Atmospheric continues to look conducive for Tropical Development next week as a MJO Pulse and a robust Convectively Coupled Kelvin Wave progress East across the Western Atlantic Basin.

[srainhoutx]

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT SUN AUG 28 2016

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

The National Hurricane Center is issuing advisories on Hurricane
Gaston, located about 600 miles east of Bermuda, and on newly
formed Tropical Depression Eight, located about 400 miles southeast
of Cape Hatteras, North Carolina.

Shower and thunderstorm activity has begun to increase near and to
the east of a weak area of low pressure located just south of the
lower Florida Keys. The low is expected to move westward into the
southeastern Gulf of Mexico on Monday, where environmental
conditions are expected to become more conducive for development,
and a tropical depression is likely to form within the next few
days. This system is then expected to move slowly northward and
northeastward over the eastern Gulf of Mexico later this week.
Regardless of development, heavy rainfall and gusty winds are likely
to continue over portions of the northwestern Bahamas, central and
western Cuba, the Florida Keys and portions of southern Florida
through Monday. Interests elsewhere in Florida and the eastern Gulf
of Mexico should continue to monitor the progress of this
disturbance.
* Formation chance through 48 hours...medium...60 percent
* Formation chance through 5 days...high...80 percent

A weak area of low pressure located near the upper Texas coast is
producing disorganized shower and thunderstorm activity over the
northwestern Gulf of Mexico and adjacent coastal areas of
southwestern Louisiana and southeastern Texas. Surface pressures
remain high in the area and the system's proximity to land is
expected to limit significant development while it moves slowly
southwestward during the next couple of days. For additional
information on the rainfall associated with this system, please see
products from your local National Weather Service office.
* Formation chance through 48 hours...low...10 percent
* Formation chance through 5 days...low...10 percent

A tropical wave is expected to move offshore of the west coast of
Africa on Tuesday. Conditions are expected to be favorable for
development of this system later this week while it moves westward
at 15 to 20 mph over the tropical eastern Atlantic.
* Formation chance through 48 hours...low...near 0 percent
* Formation chance through 5 days...medium...50 percent

&&

Public Advisories on Tropical Depression Eight are issued under WMO
header WTNT33 KNHC and under AWIPS header MIATCPAT3.
Forecast/Advisories on Tropical Depression Eight are issued under
WMO header WTNT23 KNHC and under AWIPS header MIATCMAT3.

$$
Forecaster Brennan

[srainhoutx]

Sunday afternoon Tropical briefing from Jeff:

Highly active several days across the Atlantic basin with several systems of which two are threatening the US coast.

Hurricane Gaston:
Gaston has become a category 2 hurricane over the open central Atlantic Ocean and will remain over open waters for the next few days moving toward the N and then NNE/NE. Gaston will be no threat to any land areas

TD #8:
Tropical depression 8 has formed this morning west of Bermuda. The system shows a fairly vigorous low level circulation and recent deep convection on the NW side of the circulation. There is enough organization to upgrade the system to a tropical depression and a USAF mission will investigate the system this afternoon. High pressure building over the western Atlantic has trapped this system on it southern flank and #8 will move generally westward in the direction of the NC coast over the next few days and then turn abruptly toward the N and NE as it nears the coast ahead of a strong mid level trough over the NE US by mid to late week. IT is certainly possible that TD 8 could make landfall across eastern NC as a tropical storm before the hard right turn occurs.

99L:
Much talked about 99L finally appears to be getting better organized today east of the southern FL Keys. Radar images from Key West and Miami show a much better defined low level circulation with developing banding features and increased deep convection especially to the east and southeast of the suspected center.

Global and hurricane forecast models have finally come into better agreement that 99L will continue to move west into the SE Gulf of Mexico tonight/Monday and then into the E/central Gulf on Tuesday. At that time the ridge of high pressure over the SE US is forecast to break down and erode as a weakness develops and trough crosses the NE US. Likely TD #8 nearing NC at this time will also help to weaken the ridge. This will result in a hard right (northward) turn of the system over the central Gulf of Mexico and it is even possible the system turns toward the NE/ENE, which is somewhat of a rare movement for this time of year in the Gulf of Mexico. How far the system moves into the east/central Gulf of Mexico and how strong the turn toward the N will determine where along the US Gulf coast/west coast of FL the storm will make landfall. Overall conditions appear favorable for intensification into a least a tropical storm over the Gulf of Mexico and a hurricane is certainly within the realm of possibilities.

NHC currently gives the system a high…80% chance of development over the next 5 days.

African Wave:
A strong tropical wave will emerge off the west coast of Africa around Tuesday of this week and continue to move westward at 15-20mph into the central Atlantic Ocean. There is good model agreement and support that this feature will develop has it moves westward across the Atlantic Ocean toward the Lesser Antilles. Large scale sub-tropical ridging is expected to build across much of the Atlantic behind the departing Hurricane Gaston and TD #8/99L. This will keep this developing tropical system moving on a generally westward track for the next several days.

NW Gulf Low:
A weak area of low pressure has developed over the NW Gulf of Mexico roughly 60-80 miles S of Galveston Island. This surface low is entangled on the northern edge of an upper level low located over the western Gulf of Mexico near S TX. Strong SSE wind shear is being produced over this surface feature and radar images from both Lake Charles and Houston show poor organization of thunderstorms around the center of the low. This system will drift SW over the next few days toward the middle and lower TX coast with any development likely being hampered by unfavorable upper level winds and land interaction along the TX coast. This system will bring heavy rainfall to portions of the TX coast over the next few days.

[Andrew]

NHC will initiate advisories on Tropical Depression Nine at 5 PM EDT.

[Andrew]

TROPICAL DEPRESSION NINE FORECAST/ADVISORY NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092016
2100 UTC SUN AUG 28 2016

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL DEPRESSION CENTER LOCATED NEAR 23.7N 81.7W AT 28/2100Z
POSITION ACCURATE WITHIN 25 NM

PRESENT MOVEMENT TOWARD THE WEST OR 270 DEGREES AT 8 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1009 MB
MAX SUSTAINED WINDS 30 KT WITH GUSTS TO 40 KT.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 23.7N 81.7W AT 28/2100Z
AT 28/1800Z CENTER WAS LOCATED NEAR 23.7N 81.7W

FORECAST VALID 29/0600Z 23.9N 83.6W
MAX WIND 30 KT...GUSTS 40 KT.

FORECAST VALID 29/1800Z 24.3N 85.4W
MAX WIND 35 KT...GUSTS 45 KT.
34 KT... 30NE 0SE 0SW 30NW.

FORECAST VALID 30/0600Z 24.6N 86.8W
MAX WIND 35 KT...GUSTS 45 KT.
34 KT... 30NE 0SE 0SW 30NW.

FORECAST VALID 30/1800Z 25.1N 87.6W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT... 50NE 30SE 0SW 40NW.

FORECAST VALID 31/1800Z 26.8N 87.4W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 60NE 60SE 40SW 50NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NM
ON DAY 4 AND 200 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY

OUTLOOK VALID 01/1800Z 29.0N 84.5W
MAX WIND 45 KT...GUSTS 55 KT.

OUTLOOK VALID 02/1800Z 31.0N 80.0W
MAX WIND 45 KT...GUSTS 55 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 23.7N 81.7W

NEXT ADVISORY AT 29/0300Z

[srainhoutx]

After 11 days of model watching for 99L we finally get a Tropical Depression just S of Key West.

[TexasBreeze]

There's a lot of tropical systems out there! Atlantic 8, 9, Gaston. Pacific has Madeline and Lester both threats to Hawaii.

[Ptarmigan]

After 11 days of model watching for 99L we finally get a Tropical Depression just S of Key West.

It could be Hermine or Ian. Gaston is the first major hurricane of the season.

[davidiowx]

After 11 days of model watching for 99L we finally get a Tropical Depression just S of Key West.

How confident are you on the sharp hook towards the East? Especially since the latest Recon data isn't into the models yet?

[Ptarmigan]

After 11 days of model watching for 99L we finally get a Tropical Depression just S of Key West.

How confident are you on the sharp hook towards the East? Especially since the latest Recon data isn't into the models yet?

I think they the forecast path will change. It usually changes from what I recall.

Just look at any advisories at NHC.
http://www.nhc.noaa.gov/archive/2008/