ATL: OPHELIA - Remnants - Discussion

[tobol.7uno]

Does not look like wind shear is much of an issue... Nor does dry air seem to be an issue, why are the intensity forecasts so low?

[Nimbus]

This is a neat storm to watch as it develops. Looks like an example of Fujiwara effect where the 97L and 98L vortices are orbiting each other.

http://www.ssd.noaa.gov/goes/flt/t1/loop-vis.html

[sunnyday]

Thank you, edr. I was spoken to harshly about my wanting death and destruction from a storm when all I said was that recurves are boring. I am the last person that would wish any harm to anyone, and I felt sad when I was spoken to that way.

[wxman57]

Does not look like wind shear is much of an issue... Nor does dry air seem to be an issue, why are the intensity forecasts so low?
http://img15.imageshack.us/img15/7218/wg8shtb.gif

Don't assume wind shear over the past 24 hours = wind shear 4-5 days from now.

[tobol.7uno]

Spaghetti runs all over the place and mainly away from the carib, GFS ensemble agreeing on a low lat track. I'd love to see a discussion and a forecast track from NHC right now.

GFS has been consistent while the other models have not been to consistent. Does this mean anything? We don't know.

From NHC...

...SPECIAL FEATURES...

A 1008 MB LOW PRESSURE CENTER IS NEAR 12N38W. SCATTERED MODERATE
TO ISOLATED STRONG CONVECTIVE PRECIPITATION IS FROM 8N TO 15N
BETWEEN 33W AND 42W. ISOLATED MODERATE RAINFALL TO POSSIBLE
THUNDERSTORMS ARE FROM 10N TO 14N BETWEEN 40W AND 46W...AND
FROM 6N TO 8N BETWEEN 42W AND 53W. THE SYSTEM DOES NOT HAVE
A WELL-DEFINED CENTER OF CIRCULATION AT THIS TIME. CONDITIONS
ARE EXPECTED TO REMAIN CONDUCIVE FOR A TROPICAL DEPRESSION TO
FORM IN THIS AREA LATER TODAY OR ON WEDNESDAY. THE LOW CENTER
IS FORECAST TO MOVE WESTWARD 5 TO 10 MPH.

[Extratropical94]

Does not look like wind shear is much of an issue... Nor does dry air seem to be an issue, why are the intensity forecasts so low?
http://img15.imageshack.us/img15/7218/wg8shtb.gif

If you look at the area between 40 and 50 West and north of 15 North you can see that wind shear is certainly an issue should 98 track where the spaghetti models take it.

To me it looks like shear in the whole Carib basin and over the islands in general is receding.
Maybe a precursor to more activity in October?
Anyway, if 98 stays below 14N conditions don't appear unfavorable for further development.

[wxman57]

I wouldn't assume a track south of 14N. That ridge to the north isn't very strong. Once 98L passes 50W it rounds the western side of the ridge and should start gaining significant latitude. Here's a good website to keep track of 98L.

http://rammb.cira.colostate.edu/product ... r=AL982011

With the exception of the GFDL that moves 98L like a bat out of hell due west toward the central Caribbean in 5 days, all models indicate steadily increasing shear over the next 5 days (top right panel of graphic below). Intensity consensus is around 40-45 kts.

[Gustywind]

Here is a loop of 98L progresses westward...

[wxman57]

NHC may want to see a bit more/stronger convection near the center before upgrading.

[Gustywind]

000
AXNT20 KNHC 201805
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON SEP 19 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST
FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED
ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND
METEOROLOGICAL ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1715 UTC.

...SPECIAL FEATURES...

A 1008 MB LOW PRESSURE CENTER IS NEAR 12N38W. SCATTERED MODERATE
TO ISOLATED STRONG CONVECTIVE PRECIPITATION IS FROM 8N TO 15N
BETWEEN 33W AND 42W. ISOLATED MODERATE RAINFALL TO POSSIBLE
THUNDERSTORMS ARE FROM 10N TO 14N BETWEEN 40W AND 46W...AND
FROM 6N TO 8N BETWEEN 42W AND 53W. THE SYSTEM DOES NOT HAVE
A WELL-DEFINED CENTER OF CIRCULATION AT THIS TIME. CONDITIONS
ARE EXPECTED TO REMAIN CONDUCIVE FOR A TROPICAL DEPRESSION TO
FORM IN THIS AREA LATER TODAY OR ON WEDNESDAY. THE LOW CENTER
IS FORECAST TO MOVE WESTWARD 5 TO 10 MPH.

[Caribwxgirl]

I have this spaghetti from SFWMD
http://199.imageshack.us/img199/982/storm98ophelia20sep12z.gif

Uploaded with ImageShack.us

Ok thanks they seem to be all over the place though...guess they need a center to work with.

Not really. If you remove the dozen or so GFS ensemble members, the BAM models and the 3-4 extra GFDL iterations in the plot, then you have an image like the one below. Euro and Canadian are now in agreement on a near-miss to the NE Caribbean (Maria-like track). GFS is moving that way, too. It's looking more like this storm could well miss the NE Caribbean (center, at least). And all models with the exception of the Canadian indicate increasing shear and weakening as it nears the Caribbean.

http://myweb.cableone.net/nolasue/models18zsept20.gif]

Thanks for that...that's why we need you pro-mets around here

[HurricaneWarning92]

Watch the GFDL be right this time...

[Caribwxgirl]

Anyone have the latest spaghetti models from the more reliable sources?

Latest models as of 2pm EDT or 18z
http://img827.imageshack.us/img827/7685 ... ackear.png

Thanks

[tobol.7uno]

Watch the GFDL be right this time...

GFDL has been attacking Florida this year, in the long range it probably curls around into the gulf and into Florida as a hurricane... lol
But seriously, GFDL has been a westerly outlier all year, they must have made some changes to it over the winter last year.

[tobol.7uno]

another interesting note, all of the GFS guidance does the same as GFDL, so it could be right.

[gatorcane]

I have this spaghetti from SFWMD
http://199.imageshack.us/img199/982/storm98ophelia20sep12z.gif

Uploaded with ImageShack.us

Ok thanks they seem to be all over the place though...guess they need a center to work with.

Not really. If you remove the dozen or so GFS ensemble members, the BAM models and the 3-4 extra GFDL iterations in the plot, then you have an image like the one below. Euro and Canadian are now in agreement on a near-miss to the NE Caribbean (Maria-like track). GFS is moving that way, too. It's looking more like this storm could well miss the NE Caribbean (center, at least). And all models with the exception of the Canadian indicate increasing shear and weakening as it nears the Caribbean.

http://myweb.cableone.net/nolasue/models18zsept20.gif]

and the sounds of crickets return to the board again....

[tobol.7uno]

and the sounds of crickets return to the board again....

LOL!!! Don't you just love talking so much about a storm that is likely to just be a fish storm...

[wxman57]

It could have a significant impact on the NE Caribbean.

[MGC]

98L looks real close to being upgraded IMO. Just needs a bit more convection near the CC.....MGC

[tobol.7uno]

Does not look like wind shear is much of an issue... Nor does dry air seem to be an issue, why are the intensity forecasts so low?
http://img15.imageshack.us/img15/7218/wg8shtb.gif

Don't assume wind shear over the past 24 hours = wind shear 4-5 days from now.

I am assuming a more westward track (GFS guidance) and if the current general trend with the shear continues, 98 should get max shear of 20 kt - 25 kt over the center for a short time. The only issue I see is the dry air out front 98.