ATL: CRISTOBAL - Post-Tropical - Discussion

[Fego]

As I understood, the strong/slow factors are related with missing the trough.

[Evil Jeremy]

I suspect NHC will bump up the TWO percentage to something around 70%/80% at 2am. This is bordering on tropical cyclone status. Not there yet, convection is weak at the moment, but should be refiring soon.

[Hammy]

Convection is overall decreasing and the last ASCAT pass doesn't show a fully formed LLC yet, more than likely the five day will stay the same, though the 48 hour may be bumped up a bit.

[cycloneye]

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 AM EDT THU AUG 21 2014

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

Showers and thunderstorms associated with an elongated area
of low pressure located a few hundred miles east of the Windward
Islands have changed little in organization during the past
several hours. Environmental conditions are expected to be
conducive for development during the next couple of days, and a
tropical depression could form while the system moves
west-northwestward at 10 to 15 mph across the Lesser Antilles and
over the eastern Caribbean Sea. The mountainous terrain of
Hispaniola and eastern Cuba could limit development during the first
part of the weekend, but conditions are expected to be conducive for
development early next week when the system is forecast to move near
or over the Bahamas.

Regardless of tropical cyclone formation, gusty winds and heavy
rainfall are possible across portions of the Lesser Antilles, Puerto
Rico, and the Virgin Islands tonight and Friday, and over Hispaniola
late Friday and Saturday. Interests in those islands should closely
monitor the progress of this disturbance. An Air Force Reserve
Hurricane Hunter aircraft is scheduled to investigate the low this
afternoon, if necessary.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 5 days...high...70 percent.

$$
Forecaster Brown

[abajan]

I suspect NHC will bump up the TWO percentage to something around 70%/80% at 2am. This is bordering on tropical cyclone status. Not there yet, convection is weak at the moment, but should be refiring soon.

I guess not. Surprised me too.

[wyq614]

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 AM EDT THU AUG 21 2014

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

Showers and thunderstorms associated with an elongated area
of low pressure located a few hundred miles east of the Windward
Islands have changed little in organization during the past
several hours. Environmental conditions are expected to be
conducive for development during the next couple of days, and a
tropical depression could form while the system moves
west-northwestward at 10 to 15 mph across the Lesser Antilles and
over the eastern Caribbean Sea. The mountainous terrain of
Hispaniola and eastern Cuba could limit development during the first
part of the weekend, but conditions are expected to be conducive for
development early next week when the system is forecast to move near
or over the Bahamas.

Regardless of tropical cyclone formation, gusty winds and heavy
rainfall are possible across portions of the Lesser Antilles, Puerto
Rico, and the Virgin Islands tonight and Friday, and over Hispaniola
late Friday and Saturday. Interests in those islands should closely
monitor the progress of this disturbance. An Air Force Reserve
Hurricane Hunter aircraft is scheduled to investigate the low this
afternoon, if necessary.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 5 days...high...70 percent.

$$
Forecaster Brown

It is not only an outlook but also a short forecast and analysis. To me that is rarely seen in a TWO. Maybe NHC is now confident on their forecast which may indicate that this system will be no carribbean cruiser?

[fci]

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 AM EDT THU AUG 21 2014

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

Showers and thunderstorms associated with an elongated area
of low pressure located a few hundred miles east of the Windward
Islands have changed little in organization during the past
several hours. Environmental conditions are expected to be
conducive for development during the next couple of days, and a
tropical depression could form while the system moves
west-northwestward at 10 to 15 mph across the Lesser Antilles and
over the eastern Caribbean Sea. The mountainous terrain of
Hispaniola and eastern Cuba could limit development during the first
part of the weekend, but conditions are expected to be conducive for
development early next week when the system is forecast to move near
or over the Bahamas.

Regardless of tropical cyclone formation, gusty winds and heavy
rainfall are possible across portions of the Lesser Antilles, Puerto
Rico, and the Virgin Islands tonight and Friday, and over Hispaniola
late Friday and Saturday. Interests in those islands should closely
monitor the progress of this disturbance. An Air Force Reserve
Hurricane Hunter aircraft is scheduled to investigate the low this
afternoon, if necessary.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 5 days...high...70 percent.

$$
Forecaster Brown

It is not only an outlook but also a short forecast and analysis. To me that is rarely seen in a TWO. Maybe NHC is now confident on their forecast which may indicate that this system will be no carribbean cruiser?

Agree!
For a TWO to be talking about expecting 96L to interact with Hispanola and Eastern Cuba and be in the Bahamas that far out is unusual.
Especially when it isn't even a TD yet.

[Frank2]

Pardon the hotlink and just my own opinion, but it seems the system was beginning to develop the past 6 hours but has since run into the dry air seen yesterday:

http://www.ssd.noaa.gov/PS/TROP/floater ... imated.gif

[GCANE]

Looks like it is organizing.

Anti-cyclone just to the NE of the LLC with convection firing off.

http://tropic.ssec.wisc.edu/real-time/a ... wg8shr.GIF

http://rammb.cira.colostate.edu/product ... 210115.jpg


Sat analysis showing a 25 knot wind field.

http://rammb.cira.colostate.edu/product ... 0_SWHR.GIF

[meriland23]

Convection is totally popping right now

[GCANE]

Cloud tops look to be a bit colder too

http://www.ssd.noaa.gov/PS/TROP/floater ... imated.gif

[Gustywind]

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU AUG 21 2014

...SPECIAL FEATURES...

AN ELONGATED 1009 MB ATLANTIC OCEAN LOW PRESSURE CENTER IS
LOCATED NEAR 12N54W...IN THE MONSOON TROUGH. A TROPICAL WAVE IS
ALSO ATTACHED TO THIS LOW. SCATTERED MODERATE TO ISOLATED STRONG
CONVECTION IS FROM 10N-15N BETWEEN 52W-58W. GRADUAL DEVELOPMENT
OF THIS FEATURE IS POSSIBLE DURING THE NEXT FEW DAYS...WHILE
MOVING WNW AT 10-15 KNOTS...ACROSS THE LESSER ANTILLES INTO THE
CARIBBEAN SEA. INTERESTS IN THE LESSER ANTILLES AND THE ISLANDS
OF THE NORTHEASTERN CARIBBEAN SEA SHOULD MONITOR CLOSELY THE
PROGRESS OF THIS SYSTEM. THE CHANCE FOR DEVELOPMENT INTO A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS IS MEDIUM.

[Cyclenall]

Pardon the hotlink and just my own opinion, but it seems the system was beginning to develop the past 6 hours but has since run into the dry air seen yesterday:

http://www.ssd.noaa.gov/PS/TROP/floater ... imated.gif

Doesn't look good, had better structure (that is still sort of there) 10 hours ago. I don't understand the hype surrounding this, the model guidance showing what its showing doesn't energize my enthusiasm. It instead reminds me of all the times I've been burned when watching an Invest or storm very similar to this one around about now. And those seasons were many times more favorable than this one overall. Some factors are much better for 96L, the one's that have plagued past storms since the dry-air invasion and stable airmass remains.

Looks like it is organizing.

Anti-cyclone just to the NE of the LLC with convection firing off.

http://tropic.ssec.wisc.edu/real-time/a ... wg8shr.GIF

http://rammb.cira.colostate.edu/product ... 210115.jpg


Sat analysis showing a 25 knot wind field.

http://rammb.cira.colostate.edu/product ... 0_SWHR.GIF

I was just thinking when you would stop by in the early morning hours . Still remember the hot tower comments and how everyone else got tired of reading us state it so much .

Convection is totally popping right now

Will it wrap around? That is the question.

[Gustywind]

Yellow alert have been activated for Guadeloupe and the Northern Leewards islands for a risk of showers and tstorms.

[Gustywind]

First appareance on SSD... more north than the NHC positions from 2AM.


DATE/TIME LAT LON CLASSIFICATION STORM
21/0545 UTC 13.8N 55.5W T1.0/1.0 96L -- Atlantic

[Gustywind]

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU AUG 21 2014

...SPECIAL FEATURES...

AN ELONGATED 1009 MB ATLANTIC OCEAN LOW PRESSURE CENTER IS
LOCATED NEAR 14N55W. A TROPICAL WAVE IS ATTACHED TO THIS LOW.
WIDELY SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM
10N-20N BETWEEN 51W-60W. GRADUAL DEVELOPMENT OF THIS FEATURE IS
POSSIBLE DURING THE NEXT FEW DAYS...WHILE MOVING WNW AT 10-15
KNOTS ACROSS THE LESSER ANTILLES INTO THE CARIBBEAN SEA.
INTERESTS IN THE LESSER ANTILLES AND THE NE CARIBBEAN ISLANDS
SHOULD MONITOR CLOSELY THE PROGRESS OF THIS SYSTEM. THE CHANCE
FOR DEVELOPMENT INTO A TROPICAL CYCLONE DURING THE NEXT 48 HOURS
IS MEDIUM.

[NDG]

Looking at the first vis satellite pixs it looks to me that 96L did not get that much organized as the surface during the night, it still has some time to go.

The good news with this system is that like Bertha it will bring much needed rains to the northern Leeward Islands

[Blown Away]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
349 AM EDT THU AUG 21 2014

.DISCUSSION...

CURRENTLY A LARGE AREA OF HIGH PRESSURE COVERS THE SUBTROPICS
EXTENDING FROM NORTH AFRICA TO MEXICO. A TROUGH OF LOW PRESSURE OVER
THE PACIFIC COAST OF THE US INTERRUPTS THE SUBTROPICAL HIGH. AS THIS
TROUGH CONTINUES TO AMPLIFY IN THE WEST, A PORTION OF THE
SUBTROPICAL HIGH IS DRAWN INTO THE SOUTHEASTERN US EXPANDING AND
REACHING 595 DAM BETWEEN FRIDAY AND SATURDAY AT 500MB. AS THIS
AMPLIFICATION OCCURS, A TROUGH OF LOW PRESSURE MOVES SOUTHWARD
ALONG THE EASTERN SEABOARD WITH THE HIGH EXTENDING FROM NORTHERN
MEXICO TO THE NORTHEAST US FOR EARLY NEXT WEEK. SLOWLY, THE HIGH
MOVES EASTWARD NEXT WEEK.

THE SOLUTIONS OF THE GFS AND ECMWF MODELS ARE VERY SIMILAR, EXCEPT
THAT THE ECMWF HAS A MORE PRONOUNCED TROUGH OF LOW PRESSURE,
EXTENDING FURTHER SOUTH, FOR THE ATLANTIC OCEAN EAST OF THE HIGH FOR
NEXT WEEK. THIS VOID IN PRESSURES IS WHAT COULD CHANNEL NORTHWARD
THE AREA OF DISTURBED WEATHER CURRENTLY LOCATED NE OF SOUTH AMERICA.
THE GFS MODEL IS BECOMING MORE IN LINE WITH THE ECMWF ON THE
DEPICTION OF THIS FEATURE.

THE AREA OF INCREASED MOISTURE THAT AFFECTED OUR REGION TODAY IS
NOW MOVING INTO THE GULF OF MEXICO. HOWEVER, AN AREA OF RESIDUAL
MOISTURE LINGERS BETWEEN NOW AND FRIDAY ALONG THE SOUTHERN PORTION
OF THE HIGH PRESSURE. DRIER AIR IS FORECAST TO AFFECT SOUTH
FLORIDA BEGINNING ON SATURDAY. HOWEVER, AS THE HIGH PRESSURE
DESCRIBED ABOVE OVER THE SOUTHEASTERN US GETS ELONGATED, IT WRAPS
AROUND AN AREA OF MOISTURE THAT ROTATES ALONG THE NORTHERN
PERIPHERY OF THE HIGH POSSIBLY TAKING THIS MOISTURE TO CENTRAL
FLORIDA. DUE TO THE AMPLIFIED PATTERN, DETAILS OF THIS SORT HAVE A
LOW CONFIDENCE IN TIMING. IT IS IMPORTANT TO NOTE THAT THE ECMWF
SHOWS RELATIVELY HIGH SURFACE PRESSURE STANDARD DEVIATIONS FOR
EARLY NEXT WEEK, WHICH IS INDICATIVE OF A LOW CONFIDENCE
FORECAST. IT IS VERY DIFFICULT TO KNOW WHERE THE AREA OF DISTURBED
WEATHER COULD END SINCE IT DEPENDS ON THE EASTWARD DISPLACEMENT OF
THE HIGH AND THE POSITION OF THE TROUGH IN THE WESTERN ATLANTIC.
AT THIS TIME THE UNCERTAINTY IS JUST TOO LARGE. SOUTH FLORIDA
RESIDENTS ARE ADVISED TO STAY TUNED OVER THE WEEKEND. NOTHING TO
WORRY ABOUT AT THIS TIME OTHER THAN CHECKING OUR PREPAREDNESS
PLANS. AFTER ALL, WE ARE HEADING INTO THE PEAK OF THE HURRICANE
SEASON.

NWS Miami, seems this is a tricky forecast for 96L...

[sunnyday]

So are we to understand that with the new possible recurve scenario that Fl is probably out of the woods?

[tolakram]

So are we to understand that with the new possible recurve scenario that Fl is probably out of the woods?

No, it's still too early to say that. It's looking more likely but really the system needs to consolidate and then the models might have a better idea where it will end up.

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