Tropical Wave in Central Caribbean (Ex 92L)

[Frank2]

Some serious southerly shear is to the west of this disturbance, over the central Caribbean Sea:

http://www.ssd.noaa.gov/goes/flt/t2/loop-avn.html

[southerngale]

11:30am TWO!!!

A TROPICAL WAVE ACCOMPANIED BY A WEAK AREA OF LOW PRESSURE IS
GENERATING SHOWERS AND A FEW THUNDERSTORMS OVER THE WINDWARD
ISLANDS. THIS SYSTEM HAS BECOME A LITTLE BETTER ORGANIZED TODAY
AND SOME ADDITIONAL DEVELOPMENT IS POSSIBLE DURING THE NEXT COUPLE
OF DAYS AS IT MOVES WEST-NORTHWESTWARD AT 10 TO 15 MPH. AN AIR
FORCE RESERVE RECONNAISSANCE AIRCRAFT IS SCHEDULED TO INVESTIGATE
THE SYSTEM THIS AFTERNOON.

WOW.

Just goes to show you how quick things change. 6 hours ago:

TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
530 AM EDT SUN AUG 13 2006

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

TROPICAL STORM FORMATION IS NOT EXPECTED THROUGH MONDAY.

FORECASTER MAINELLI/BEVEN

Of course that could still be right.

[Frank2]

That's only because there wasn't an NHC forecaster on duty overnight (none is on duty when both the Atlantic and Pacific are quiet) - aside from any unusually rapidly-forming tropical disturances during the mid-shift period (there weren't any), the NWS forecaster will leave the TWO in the negative until the NHC hurricane forecaster comes on duty the next morning...

Frank

[wxman57]

IF WE HAVE RECONS GOING IN WITH THE FIRST DISCUSSION ON THIS INVEST WE HAVE SOMETHING MAJOR>>>>

Not necessarily, I believe that recon is already positioned nearby. Currently, it IS just a thunderstorm or two, but it appears to have good outflow. Certianly no LLC, but there is a mid-level vorticity center (spin). I think it may have as much as a 20% shot at becomming a TS in the next few days. Fairly strong ridge builds over the north-central Gulf by the end of this week. That should prevent any NW movement toward the central Gulf. More likely, a W-WNW track toward the southern Yucatan.

Also, by Friday, at least the GFS indicates quite high wind shear across the northwest Caribbean. So any movement in that direction would not favor intensification.

[Derek Ortt]

There are people at TPC there 24 hours a day. Not sure if a specialist is on duty; however

[brunota2003]

also to note, in the recon plan of the day they did mention todays flight is resources permitting...

[Derek Ortt]

shear may be over 20KT in 4 days

That said, as bad as the models are at predicting shear, a large anti-cyclone will probably develop

[kenl01]

Some serious southerly shear is to the west of this disturbance, over the central Caribbean Sea:

http://www.ssd.noaa.gov/goes/flt/t2/loop-avn.html

Thank You.
Even Steve Lyons mentioned this morning that it's not expected to develop much at this time.............

[wxman57]

shear may be over 20KT in 4 days

That said, as bad as the models are at predicting shear, a large anti-cyclone will probably develop

Another factor to consider, Derek, is timing. Development typically occurs at 9am Saturdays, when we're generally off work. It would be unusual for something to develop when it's more "convenient".

[Extremeweatherguy]

IF WE HAVE RECONS GOING IN WITH THE FIRST DISCUSSION ON THIS INVEST WE HAVE SOMETHING MAJOR>>>>

Not necessarily, I believe that recon is already positioned nearby. Currently, it IS just a thunderstorm or two, but it appears to have good outflow. Certianly no LLC, but there is a mid-level vorticity center (spin). I think it may have as much as a 20% shot at becomming a TS in the next few days. Fairly strong ridge builds over the north-central Gulf by the end of this week. That should prevent any NW movement toward the central Gulf. More likely, a W-WNW track toward the southern Yucatan.

Also, by Friday, at least the GFS indicates quite high wind shear across the northwest Caribbean. So any movement in that direction would not favor intensification.

I think that sounds reasonable. However, the NWS in Houston thinks the high will shift north by the end of the week. If that was the case, wouldn't the track be different? From the morning discussion:

THIS WILL CONTINUE
THROUGH THE COMING WEEKEND WITH DEEPENING EAST/SOUTHEAST FLOW AS
THE NEXT TUTT APPROACH THE TEXAS COAST AND THE UPPER HIGH SHIFTS
FARTHER NORTH. TEMPERATURES WILL START TO MODERATE DURING THIS
PERIOD DUE INCREASING CLOUD COVER AND AFOREMENTIONED INCREASING
MOISTURE LEVELS. 37

[canetracker]

Well lets hope the shear is high. The SST's could certainly support a nice cane. http://polar.ncep.noaa.gov/ofs/aofs_images/aofs_sst_nowcast_natl.png

[Derek Ortt]

of course this develops when we're not at the office

It's too much to expect something to develop at 5 P.M. on a weekday

[Frank2]

That's true, Derek - the TPC staff are there 24 hours a day, but, the NHC forecaster is not on mid-shift duty when there are negative TWO's in both basins...

Just an aside - due to automation and budget, the NHC (and especially HRD) staff sizes are considerably smaller than when I worked for them in the 1980's...

Frank

[Ola]

Hmm ...

Appart from a wave generating thunderstorms, I really dont see organization from looking at the vis loop.

Where do you think the center could be? If there was one? Or where do you think a center could form? 13.5 62 ?

[skysummit]

Geez....I go to work for 3 hours in the Superdome and come back out to two Invests....UNREAL.

[Tampa Bay Hurricane]

These invests have really popped. 2 invests in one morning.
Wow.
This shows some possibilities of development with lower shear
and higher ssts.
The convection looks moderately strong and it appears to be
embedded in a moist area from the water vapor imagery
even though dry air is close by and to the north.

[fci]

Recon seems fast.

I think they are bored too.

[Tampa Bay Hurricane]

Look at this potential...Mind-Boggling...
Sub-880 mb in the South East GOM!
And a very large area of 880-890 mb in the GOM!
A lot of Category 5 support in the Central Atlantic as well.
http://wxmaps.org/pix/hurpot.html#ATL

[Thunder44]

These invests have really popped. 2 invests in one morning.
Wow.
This shows some possibilities of development with lower shear
and higher ssts.
The convection looks moderately strong and it appears to be
embedded in a moist area from the water vapor imagery
even though dry air is close by and to the north.

I'm little suprised too. I was just gone for a few hours for church this morning. I comeback to two invests and plane already being sent to one of them.

The plane suprises me even more because it pretty clear that by looking at obs over the islands that there is no closed LLC at this time.

[Sanibel]

This is weird. The last three waves to pass through this area have gone into pseudo formation as if the area was highly favorable.

If you look at the visible loop, the surface flow seems to have slowed considerably in front of this one in the Caribbean.


I suppose I should learn the lesson from my last two conspicuous busts and say this one will be eaten by the same negative conditions as the previous two.