Ex Invest 99L in Western Atlantic

[AJC3]

The vort center associated with this wave, which had been a bit more compact earlier, appears to be elongating toward the NE, and has gained quite bit of latitude, with the center of the vort lobe now crossing 25N. What's left of the low level ridge axis has dropped south to near Lake Okeechobee and will collapse by Thursday, so SW low-mid level flow is poised to develop across the Florida peninsula. Since a shallow feature such as this will follow the low to mid level steering flow, there's no way that the wave will reach the FL east coast now, and whatever does or (more likely) doesn't develop out of this wave should eventually turn NE somewhere between 75 and 77W.

Boy, that ridge axis is very strong, though.

Maybe I'm just seeing things, but there's seems to be a hint of a left turn in recent frames.

The low to mid level reflection of the Atlantic ridge is quite weak west of 75W. You can pretty much ignore what's going on between 500MB and 200MB. The system is too shallow to be steered by these winds aloft.

[kpost]

FROM THE BAHAMAS ISLANDS INTO THE CARIBBEAN SEA...
http://www.nhc.noaa.gov/text/refresh/MIATWDAT+shtml/061757.shtml?

FROM THE BAHAMAS ISLANDS INTO THE CARIBBEAN SEA...AN UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 22N73W BETWEEN MAYAGUANA AND LITTLE INAGUA IN THE SOUTHERN BAHAMAS
JUST WEST OF THE TURKS AND CAICOS ISLANDS. A TROUGH CONTINUES
FROM THE CYCLONIC CENTER THROUGH THE WINDWARD PASSAGE INTO THE
CARIBBEAN SEA NEAR 15N80W DIVING INTO THE SOUTHWESTERN CORNER
OF THE AREA. SHOWERS AND POSSIBLE THUNDERSTORMS ARE ALONG THE
COASTS FROM PANAMA TO SOUTHEASTERN COSTA RICA. SCATTERED
MODERATE SHOWERS FROM 24N TO 26N BETWEEN 73W AND 76W JUST
NORTHEAST OF THE BAHAMAS. ISOLATED MODERATE SHOWERS ARE JUST
NORTHEAST OF JAMAICA. THE 72W/73W TROPICAL WAVE APPEARS TO BE
LINED UP WITH SHOWERS AND POSSIBLE THUNDERSTORMS IN NORTHERN
COLOMBIA FROM 9N TO 10N JUST WEST OF THE BORDER WITH VENEZUELA.
UPPER LEVEL ANTICYCLONIC FLOW CURVES FROM COLOMBIA INTO THE
CARIBBEAN WATERS TOWARD HISPANIOLA. SHOWERS AND THUNDERSTORMS
ARE FROM 10N TO 13N BETWEEN 62W AND 65W JUST NORTH OF THE ITCZ
AND POSSIBLY UNDER A NEARBY MIDDLE LEVEL TROUGH.

Can someone tell me what this all means.

[boca]

I think we should be put under a high cirrus cloud warning from the approach of ex99L.Because of the digging trough its not supposed to reach Florida's east coast.

[Honeyko]

> Eyeball-projected 0804 1930Z center-fix: just a sliver southeast of 22N/62W. WNW heading. SAL still to the east, barging it forward.

> Eyeball-projected (from IR2) 0805 0845Z center-fix: 22.5N/66W. W/WNW heading continues.

> Eyeball-projected 0805 1705Z center-fix: 23N/68W...WNW

> Eyeball-projected (from IR2) 0806 0645Z center-fix: 23N/72W. due W heading.

> Eyeball-projected 0805 1645Z center-fix: 24.5N/74W...movement NW.

Eyeball-projected 0805 2045Z center-fix: 24.75N/74.75W...movement WNW

[storms in NC]

From what I read here XX99L could in up in the gulf. if that happen then it could rebuild itself back up and do a little more. The Gulf is like a big pot of bowing water. I only took parts of this not the whole page.

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT WED AUG 6 2008

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...



1. A SMALL AREA OF SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A TROPICAL
WAVE IS LOCATED JUST EAST OF THE CENTRAL BAHAMAS AND IS MOVING
WESTWARD AT 10 TO 15 MPH. CONDITIONS ARE NOT FAVORABLE FOR
SIGNIFICANT DEVELOPMENT OF THIS SYSTEM...BUT IT COULD PRODUCE
PERIODS OF SHOWERS OVER PORTIONS OF THE BAHAMAS AND SOUTHERN
FLORIDA DURING THE NEXT DAY OR TWO.

[AJC3]

From what I read here XX99L could in up in the gulf. if that happen then it could rebuild itself back up and do a little more. The Gulf is like a big pot of bowing water. I only took parts of this not the whole page.

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT WED AUG 6 2008

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...



1. A SMALL AREA OF SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A TROPICAL
WAVE IS LOCATED JUST EAST OF THE CENTRAL BAHAMAS AND IS MOVING
WESTWARD AT 10 TO 15 MPH. CONDITIONS ARE NOT FAVORABLE FOR
SIGNIFICANT DEVELOPMENT OF THIS SYSTEM...BUT IT COULD PRODUCE
PERIODS OF SHOWERS OVER PORTIONS OF THE BAHAMAS AND SOUTHERN
FLORIDA DURING THE NEXT DAY OR TWO.

The only possible way any part of this vortlobe could make it to near 80W would be if it that portion of it that's south of 25N was to fracture off from the rest of it (again). Even if that was to occur, the main piece of vorticity would still turn northward along 75-76W, and then NE away from FL, leaving an even smaller piece to drift off toward the west. I don't foresee this happenening, but hey, I've been wrong before...after all I'm a meteorologist.

We'll see tonight...

[storms in NC]

From what I read here XX99L could in up in the gulf. if that happen then it could rebuild itself back up and do a little more. The Gulf is like a big pot of bowing water. I only took parts of this not the whole page.

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT WED AUG 6 2008

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...



1. A SMALL AREA OF SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A TROPICAL
WAVE IS LOCATED JUST EAST OF THE CENTRAL BAHAMAS AND IS MOVING
WESTWARD AT 10 TO 15 MPH. CONDITIONS ARE NOT FAVORABLE FOR
SIGNIFICANT DEVELOPMENT OF THIS SYSTEM...BUT IT COULD PRODUCE
PERIODS OF SHOWERS OVER PORTIONS OF THE BAHAMAS AND SOUTHERN
FLORIDA DURING THE NEXT DAY OR TWO.

The only possible way any part of this vortlobe could make it to near 80W would be if it that portion of it that's south of 25N was to fracture off from the rest of it (again). Even if that was to occur, the main piece of vorticity would still turn northward along 75-76W, and then NE away from FL, leaving an even smaller piece to drift off toward the west. I don't foresee this happening, but hey, I've been wrong before...after all I'm a meteorologist.

We'll see tonight...

don't think of this in any other way but a open wave that lost it's other half in a divorce yesterday and took the energy in the settlement That is what I thought but the way I read it it gave me the impression that the wave would go into the gulf. We here in NC and SC really need a good slow TD for the rain. I have seen farmer cut down their corn cause the sun burned it up. So there is going to be a big shortest on corn this year. from flood to droughts

[SouthFloridawx]

[MiamiensisWx]

The upper low to the SSE of the system has continued to induce strong upper level shear over the convection, as I originally anticipated. Note that the convective tops are "knocked down" as the wave axis and associated low level convergence/vorticity moves away from the upper low. As Tony mentioned, the strongest low level vorticity at 850 mb is situated on the northern side and is turning NW as a stalled front to the north erodes the surface ridge, displacing the axis further east. A weak surface trough extends SW into the eastern Gulf of Mexico per recent surface analysis. With the low/mid level wind vectors becoming southerly over the Florida peninsula, a recurvature remains on the table as the fractured wave axis turns NW as well.

In the end, my original (meager) expectations for this one are verifying quite nicely.

[cpdaman]

sheared from an ULL to the sse?

this map says

http://cimss.ssec.wisc.edu/tropic/real- ... g8shr.html

no soup for you

[MiamiensisWx]

sheared from an ULL to the sse?

this map says

http://cimss.ssec.wisc.edu/tropic/real- ... g8shr.html

no soup for you

I believe those charts refer to the absolute shear values, as opposed to relative shear. The system experienced the lower absolute shear values directly under the upper low. When the system moved out from the upper low, it experienced the stronger NE UL shear from the upper low. This is associated with the upper level winds and circulation of the upper low. Note that WV imagery does indicate the presence of an upper low centered nearly directly over ex-99L. Precisely, it is just SSE of ex-99L.

The 18Z operational GFS initialization also indicates and confirms the presence of an upper low at 300 mb:

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/carib/gfs/18/images/gfs_300_000l.gif

[SouthFloridawx]

sheared from an ULL to the sse?

this map says

http://cimss.ssec.wisc.edu/tropic/real- ... g8shr.html

no soup for you

Ahhh... I think you are the one that gets no soup. There is an upper level feature to the SSE of the system (swirl) in question here.

[SouthFloridawx]

Hopefully you know I was joking for the most part. Sarcasm doesn't come across too well on the information superhighway.

sheared from an ULL to the sse?

this map says

http://cimss.ssec.wisc.edu/tropic/real- ... g8shr.html

no soup for you

[cpdaman]

yes yes southfloridawx still

i think any shear is very weak associated with that weak ull


gfs 200 mb analysis shows (top left panel)

http://www.nco.ncep.noaa.gov/pmb/nwprod ... _012.shtml

note the NE upper winds extend well NE of florida and should you go back further (12 hours) , show that this area of high shear moved in from the NORTH,

http://www.nco.ncep.noaa.gov/pmb/nwprod ... _000.shtml

thus not from the Ull to the sse

[Honeyko]

Well, it doesn't look quite as nice this evening, but there's still rotation struggling.

Mediocre chance of the following happening: a large CB complex forms SW of the center and develops a mid-level circulation overnight, which drags at the low-level circulation while the CB complex is blown westward. Otherwise, it's looking more and more likely that it may stall and mill around for awhile.

(Despite the continued raggedness of 99, one thing has always impressed me about it: It hasn't had any collapse/outflow boundaries.)

==//==

Cap? There's SE shear at I estimate 20,000ft from the upper-low, and higher-level NW shear from the stuff north. There's a lot of layers in the cake around the Caribbean.

[Patrick99]

Where's all this SW flow over Florida people are talking about? Any convection that formed today over S. FL was quickly blown WSW. Seems like easterly flow to me. If there had been SW flow, I would likely have received some rain.

[JonathanBelles]

the flow will be changing back to SWrly before the possible front this weekend.

[kpost]

[/quote]
I believe those charts refer to the absolute shear values, as opposed to relative shear. The system experienced the lower absolute shear values directly under the upper low. When the system moved out from the upper low, it experienced the stronger NE UL shear from the upper low. This is associated with the upper level winds and circulation of the upper low. Note that WV imagery does indicate the presence of an upper low centered nearly directly over ex-99L. Precisely, it is just SSE of ex-99L.

The 18Z operational GFS initialization also indicates and confirms the presence of an upper low at 300 mb:

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/carib/gfs/18/images/gfs_300_000l.gif[/quote]


that looks like a closed low when you zoom, is an upper low meaningful like a surface or midlevel low? newbie question sorry.

[AJC3]

Where's all this SW flow over Florida people are talking about? Any convection that formed today over S. FL was quickly blown WSW. Seems like easterly flow to me. If there had been SW flow, I would likely have received some rain.

Noone said there was SW flow over south Florida today. In fact, the low level ridge axis remains north of south Florida - near or just north of Lake Okeechobee. To the north of the lake, the synoptic low level wind flow over Florida is quite weak today due to the proximity of the ridge (sea breezes are dominating the circulation pattern).

However, over the next day and beyond, every single piece of reliable guidance shows moderate SW flow gradually developing and deepening from the surface up through 700 MB.

[cpdaman]

honeyko where is your latest eyeballing of the center, i am having a tuff time locating this