ATL: ERNESTO - Post-Tropical

[cycloneye]

Some progress. Came out of the Too Weak.

31/1145 UTC 9.2N 40.6W T1.0/1.0 99L -- Atlantic

[cycloneye]

12z Best Track

AL, 99, 2012073112, , BEST, 0, 93N, 396W, 20, 1010, DB

ftp://ftp.nhc.noaa.gov/atcf/tcweb/inves ... 012.invest

[cycloneye]

12z Models

Code: Select all

WHXX01 KWBC 311245
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS NATIONAL HURRICANE CENTER MIAMI FL
1245 UTC TUE JUL 31 2012
 
DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.
 
ATLANTIC OBJECTIVE AIDS FOR
 
DISTURBANCE INVEST (AL992012) 20120731 1200 UTC
 
        ...00 HRS...   ...12 HRS...   ...24 HRS. ..   ...36 HRS...
        120731  1200   120801  0000   120801  1200   120802  0000
 
         LAT    LON     LAT    LON     LAT    LON     LAT    LON
BAMS     9.3N  39.6W   10.1N  43.1W   10.5N  46.9W   10.5N  50.6W
BAMD     9.3N  39.6W    9.8N  41.7W   10.2N  43.7W   10.6N  45.5W
BAMM     9.3N  39.6W    9.8N  42.1W   10.2N  44.5W   10.5N  46.7W
LBAR     9.3N  39.6W    9.9N  42.1W   10.3N  44.9W   10.6N  47.6W
SHIP        20KTS          24KTS          30KTS          37KTS
DSHP        20KTS          24KTS          30KTS          37KTS
 
        ...48 HRS...   ...72 HRS...   ...96 HRS. ..   ..120 HRS...
        120802  1200   120803  1200   120804  1200   120805  1200
 
         LAT    LON     LAT    LON     LAT    LON     LAT    LON
BAMS    10.4N  54.2W    9.4N  60.6W    9.2N  65.4W   10.5N  68.3W
BAMD    10.9N  47.3W   11.7N  51.1W   13.9N  55.6W   16.8N  60.0W
BAMM    10.9N  48.9W   11.8N  53.5W   13.5N  58.8W   15.7N  64.3W
LBAR    10.7N  50.6W   10.9N  56.1W   11.5N  60.3W   13.5N  64.8W
SHIP        44KTS          56KTS          61KTS          60KTS
DSHP        44KTS          56KTS          61KTS          60KTS
 
         ...INITIAL CONDITIONS...
LATCUR =   9.3N LONCUR =  39.6W DIRCUR = 280DEG SPDCUR =  13KT
LATM12 =   8.9N LONM12 =  36.6W DIRM12 = 280DEG SPDM12 =  12KT
LATM24 =   8.7N LONM24 =  35.5W
WNDCUR =   20KT RMAXWD =   80NM WNDM12 =   20KT
CENPRS = 1010MB OUTPRS = 1011MB OUTRAD =  150NM SDEPTH =   S
RD34NE =    0NM RD34SE =    0NM RD34SW =    0NM RD34NW =   0NM
 


[cycloneye]

GFS Ensembles are Caribbean Bound.

[Gustywind]

Some progress. Came out of the Too Weak.

31/1145 UTC 9.2N 40.6W T1.0/1.0 99L -- Atlantic

Here is a recap

DATE/TIME LAT LON CLASSIFICATION STORM
31/1145 UTC 9.2N 40.6W T1.0/1.0 99L
31/0545 UTC 9.3N 38.5W TOO WEAK 99L
30/2345 UTC 9.0N 37.7W TOO WEAK 99L
30/1745 UTC 9.0N 37.1W TOO WEAK 99L
30/1145 UTC 8.9N 35.1W TOO WEAK 99L

[cycloneye]

This morning's discussion of 99L by Dr Jeff Masters.

A tropical wave (Invest 99L) near 9°N 41°W, halfway between the Lesser Antilles Islands and the coast of Africa, has the potential to develop into a tropical depression later this week as it moves westward at 10 - 15 mph. Visible satellite loops show that the disturbance now has a moderate amount of poorly-organized heavy thunderstorms that continue to slowly increase in intensity and areal coverage. There is no surface circulation, but some counter-clockwise rotation of the large-scale cloud pattern is evident. Water vapor satellite loops show that 99L has a reasonably moist environment. The latest Saharan air layer analysis shows that the dry air from the Sahara lies to the north of 99L and is currently not affecting the storm. WInd shear over the disturbance is a light 5 - 10 knots, and ocean temperatures are 28°C, (82°F) which is well above the 26.5°C (80°F) threshold typically needed to allow formation of a tropical depression.


Forecast for 99L

Wind shear is expected to remain light through Friday, and ocean temperatures will remain near 28°C, according to the 8 am EDT run of the SHIPS model. However, a band of high wind shear of 20 - 40 knots associated with the subtropical jet stream lies just to the north of 99L, and it would not be a surprise to see 99L experience some higher shear conditions than are currently forecast. The farther north 99L gets, the higher the shear it will experience, and the SHIPS model is predicting shear in the moderate range, 10 - 20 knots, for Saturday - Sunday, as the storm works its way to 15°N. The disturbance is at 9°N, which is close enough to the Equator that the storm will have some difficultly getting spinning. Most of the models are showing some slow development of 99L. There are some major differences in the predicted forward speed of 99L, with the ECMWF and UKMET models predicting the storm will reach the Lesser Antilles on Friday, and the GFS predicting a later arrival, on Saturday. At 8 am Tuesday, NHC gave 99L a 20% chance of developing into a tropical depression by Thursday morning. I expect the storm will begin having trouble with tendrils of dry air reaching down from the north at times this week, but give 99L a 50% chance of eventually developing into Tropical Storm Ernesto sometime in the next ten days. Residents and visitors to the Lesser Antilles Islands should anticipate heavy rains and strong winds from 99L beginning to affect the islands as early as Friday morning. The long-range fate of 99L next week is uncertain. A track west to west-northwest through the Caribbean, or to the northwest towards the U.S. East Coast are both possible. The storm is less likely to survive if it heads northwest towards the U.S.

[PTrackerLA]

JB seems to think 99L develops into a tropical storm by the time it reaches the islands then weakens to an open wave in the Caribbean. I suppose conditions will just be too hostile once it reaches there, we'll see.

[Aric Dunn]

wont see development till it can lift north a little away from the ITCZ.

[cycloneye]

[abajan]

Far from shifting northward, it seems to me that the models have taken a decidedly southern turn and are more in agreement with each other. It's early days yet but with memories of Tomas still fresh in my mind, this is a bit disconcerting.

[TropicalAnalystwx13]

Conditions don't seem to be as unfavorable in the Caribbean. At least, not as bad as I thought there would be. Wind shear is lowering, and taking a look at buoy data and the RGB satellite loop, trade winds aren't all that fierce. This is probably why the latest GFS run keeps this as a tropical cyclone longer than originally...

[adam0983]

Invest 99L is looking much better organized this morning. Based on radar and presentation of this system. I think this might already be a tropical depression.

[cycloneye]

Conditions don't seem to be as unfavorable in the Caribbean. At least, not as bad as I thought there would be. Wind shear is lowering, and taking a look at buoy data and the RGB satellite loop, trade winds aren't all that fierce. This is probably why the latest GFS run keeps this as a tropical cyclone longer than originally...

Do you have the data of Shear and the bouy?

[mcheer23]

Looking better! At least enough to warrant a code orange in a few hours.

[cycloneye]

Certainly,vorticity has continued to increase.

[wxman57]

Conditions don't seem to be as unfavorable in the Caribbean. At least, not as bad as I thought there would be. Wind shear is lowering, and taking a look at buoy data and the RGB satellite loop, trade winds aren't all that fierce. This is probably why the latest GFS run keeps this as a tropical cyclone longer than originally...

Do you have the data of Shear and the bouy?

Here's the wind shear analysis:
http://tropic.ssec.wisc.edu/real-time/w ... oom=&time=

Relatively light in the eastern Caribbean now. TUTT over the western-central Caribbean producing 30-35kts shear.

[cycloneye]

That is interesting 57. It may survive then the Eastern Caribbean graveyard after all.

[Aric Dunn]

There is improvement this morning. evident curved banding and convection firing over the center and has maintained fairly well. looks like t might be starting to lift away from the ITCZ

[Aric Dunn]

Far from shifting northward, it seems to me that the models have taken a decidedly southern turn and are more in agreement with each other. It's early days yet but with memories of Tomas still fresh in my mind, this is a bit disconcerting.

This southern shift is likelt in response to the models have weaker system rather than earlier runs where they maintained an actualy cyclone right now the global models are opening it up to wave and keeping farther south. notice both the cmc, nogaps, and deep BAM which have a deeper system have a more WNW motion. If it deepens beyond what the global models are showing then expect a more north of west motion to come back to the models.

[cycloneye]

Another loop. Orange at 2 PM?