TD#9

MortisFL · #401 Postby **MortisFL** » Sat Aug 06, 2005 5:08 am

We've heard just about everything with this system. NHC is going with 2 scenarios.

From 5:00am Discussion on TD #9:

#1: BY 72 HOURS...THE CYCLONE WILL BE OVER WARMER WATER
AND MORE STEADY INTENSIFICATION AND DEEPENING OF THE VERTICAL
CIRCULATION SHOULD OCCUR...WHICH SHOULD ALLOW THE CYCLONE TO BE
STEERED SLOWLY NORTHWESTWARD BY THE DEEP-LAYER FLOW TOWARD AN
EXPECTED WEAKNESS IN THE SUBTROPICAL RIDGE BETWEEN 55W-60W
LONGITUDE

#2: IF THE STORM MOVES MORE WESTWARD AND STAYS
BELOW 20N LATITUDE THROUGH 72 HOURS...THEN IT MAY NEVER FEEL THE
WEAKNESS IN THE RIDGE AND NOT TURN NORTHWESTWARD. SINCE THE GLOBAL
MODELS ARE ALREADY TOO FAR TO THE NORTH OR RIGHT OF THE CURRENT
POSITION AND MOTION...THE OFFICIAL TRACK WAS SHIFTED TO THE LEFT OF
THE PREVIOUS FORECAST TRACK...

#402 Postby **cycloneye** » Sat Aug 06, 2005 6:22 am

THE CENTER OF TROPICAL DEPRESSION NINE AT 06/0900 UTC WAS NEAR
17.7N 41.7W MOVING WNW 13 KT. THE ESTIMATED MINIMUM CENTRAL
PRESSURE IS 1008 MB. THE MAXIMUM SUSTAINED WIND SPEED IS 30 KT
WITH GUSTS TO 40 KT. SEE THE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC OR MIATCPAT4/ WTNT34
KNHC FOR MORE DETAILS. ALTHOUGH THE LOW-LEVEL CENTER IS STILL
WITHOUT ANY DEEP CONVECTION... TSTMS HAVE COME A LITTLE CLOSER
TO THE CENTER TONIGHT AND ARE SIGNIFICANTLY STRONGER THAN
EARLIER... SUGGESTING THE ENVIRONMENT MIGHT BE LESS STABLE.
WIDELY SCATTERED MODERATE CONVECTION IS FROM 14.5N-17.5N BETWEEN
39W-41W WITH A FEW TSTMS WITHIN 60 NM OF 19.5N40.5W. CIRRUS
CLOUDS CAN STILL BE SEEN ON SATELLITE MOVING W TO E... A SIGN
THAT WLY SHEAR REMAINS. COMPUTER MODELS SUGGEST THAT CONDITIONS
WILL REMAIN HOSTILE FOR SIGNIFICANT DEVELOPMENT FOR THE NEXT
COUPLE OF DAYS.. WHEN THEREAFTER SLIGHTLY LOWER SHEAR AND WARMER
WATER COULD AID IN THE ORGANIZATION OF THE DEPRESSION.

From 8:05 AM Discussion.

Thunder44 · #403 Postby **Thunder44** » Sat Aug 06, 2005 6:48 am

TD 9 is back in business.

http://www.ssd.noaa.gov/PS/TROP/DATA/RT ... -loop.html

BensonTCwatcher · #404 Postby **BensonTCwatcher** » Sat Aug 06, 2005 6:50 am

I think it was a good call to leave this thread open. ( Tks cycloneeye) My earlier prediction was 80% it gets sucked into the weakness and dies 20% it hangs on westward.

I though this would pan out in 24 hours. I misjudged the fwd speed. I will revise my prediction at this point and officially flip=flop. Pretty easy to say that now huh? OK then, factors to consider for 12-24 hours:

NOT AN OFFICIAL FORECAST, JUST MY THOUGHTS

1. Interesting that the global models don't even see TD9 and yet she is there.

2. We likely won't have any worthwhile model runs on the storm unless we get a sudden intensification, but I predict they will get better by tonight based on improving center of LLC but the trend is telling.

3. The next big thing to look for is what happens around 57-60 west I put much less emphasis on lattitude at this point based on the solid westerlies at all levels likely to steer this storm no matter how high she develops. Intensity will drive the gain in lattitude.

All this to me will make the difference between this system entering the GOM or recurving short of the Carolinas.

Not much new here I know, but comments welcomed

#405 Postby **cycloneye** » Sat Aug 06, 2005 6:56 am

Thunder44 wrote:TD 9 is back in business.

http://www.ssd.noaa.gov/PS/TROP/DATA/RT ... -loop.html

Agree that it looks better despite the center is still exposed.Somewhat less shear and increased warmer waters will allow it to organize more and be Irene in the next 12-24 hours.However it still has to deal with some dry air around.

MortisFL · #406 Postby **MortisFL** » Sat Aug 06, 2005 7:02 am

Yep around 55-60W is where the models diverge. It will be interesting to see what direction she takes.

#407 Postby **Deenac813** » Sat Aug 06, 2005 7:04 am

This is so interesting. I have been reading these posts for days and was not going to check it this morning figuring TD9 was dead. And now she is looking better. Go figure!

johngaltfla · #408 Postby **johngaltfla** » Sat Aug 06, 2005 7:36 am

Once it's firmly past 50W I'm guessing we'll have Irene and something very interesting to deal with by the end of next week. :eek:

#409 Postby **cycloneye** » Sat Aug 06, 2005 7:40 am

TROPICAL DEPRESSION NINE (AL092005) ON 20050806 1200 UTC

...00 HRS... ...12 HRS... ...24 HRS... ...36 HRS...
050806 1200 050807 0000 050807 1200 050808 0000

LAT LON LAT LON LAT LON LAT LON
BAMD 17.7N 41.9W 18.2N 43.2W 18.5N 44.4W 18.9N 45.7W
BAMM 17.7N 41.9W 18.5N 43.8W 19.0N 45.5W 19.5N 47.1W
A98E 17.7N 41.9W 18.2N 43.9W 18.7N 45.6W 19.4N 47.0W
LBAR 17.7N 41.9W 18.4N 43.9W 19.3N 46.0W 20.2N 48.3W
SHIP 30KTS 30KTS 30KTS 33KTS
DSHP 30KTS 30KTS 30KTS 33KTS

...48 HRS... ...72 HRS... ...96 HRS... ..120 HRS...
050808 1200 050809 1200 050810 1200 050811 1200

LAT LON LAT LON LAT LON LAT LON
BAMD 19.4N 47.0W 20.7N 50.0W 22.7N 53.8W 24.9N 57.5W
BAMM 19.8N 48.8W 20.7N 52.5W 22.0N 56.5W 23.5N 61.0W
A98E 20.2N 48.3W 22.3N 51.4W 25.0N 54.4W 28.4N 56.0W
LBAR 21.3N 50.9W 23.4N 55.6W 26.0N 58.9W 27.9N 61.2W
SHIP 36KTS 43KTS 50KTS 53KTS
DSHP 36KTS 43KTS 50KTS 53KTS

...INITIAL CONDITIONS...
LATCUR = 17.7N LONCUR = 41.9W DIRCUR = 285DEG SPDCUR = 11KT
LATM12 = 17.2N LONM12 = 39.8W DIRM12 = 290DEG SPDM12 = 14KT
LATM24 = 15.6N LONM24 = 36.8W
WNDCUR = 30KT RMAXWD = 50NM WNDM12 = 30KT
CENPRS = 1008MB OUTPRS = 1012MB OUTRAD = 200NM SDEPTH = M
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM

12:00z model guidance

Hyperstorm · #410 Postby **Hyperstorm** » Sat Aug 06, 2005 7:42 am

Even though TD #9 is deepening convection on the SE quadrant as we type, the LLC has become less well-defined since yesterday.

The dry air/cool SSTs/westerly wind shear causing a lack of convection during the past 24-36 hours have been slowly killing the spin. If we don't see the convection come closer to the center soon, it is possible the LLC will dissipate due to a lack of forcing. On the other hand, if the convection moves closer to the center, it will create a tighter LLC that will keep it alive.

#411 Postby **wxman57** » Sat Aug 06, 2005 7:53 am

Hmm, my first impression upon looking at the first static visible image this morning was that TD 9 had weakened to a tropical wave. I couldn't see the center well on that static image. Putting the satellite in motion, I can still see a spin, there just aren't as many clouds involved in the rotation today. However, there is one squall developing east of the exposed LLC, something that was missing yesterday.

I'm at home today, so it's a little harder to measure motion of the center (plus the center is harder to track). But it looks to be around 280-290 deg. Since it's already at the latitude of the northern Caribbean Sea, it should pass safely to the north of the islands. Long-term, the weaker status means more westerly movement, probably left of the NHC track. If it doesn't dissipate, then there may be a chance it could miss the trof to the north and eventually threaten the east U.S. coast. But that's a LONG way off and it's way too early to have any confidence in the track beyond about 3 days.

Here's a great model plot. The BAMM/BAMS track is what I think may be more likely. If TD 9 doesn't hook north as it passes the trof between 50-55W then it may continue W-WNW:

http://euler.atmos.colostate.edu/~vigh/ ... early1.png

#412 Postby **wx247** » Sat Aug 06, 2005 7:53 am

How many pages are we going to go before we close this? Wasn't 15 the limit?

WindRunner · #413 Postby **WindRunner** » Sat Aug 06, 2005 7:54 am

All the models are too far north for how I'm thinking. LBAR looks good for the entire track if it was shifted to the south some later in the period, but it sure isn't going for that weakness.

#414 Postby **cycloneye** » Sat Aug 06, 2005 7:59 am

wx247 wrote:How many pages are we going to go before we close this? Wasn't 15 the limit?

Garrett the staff made consultations about this and after discussing it we decided to keep long important threads without any limit of pages.

#415 Postby **storms in NC** » Sat Aug 06, 2005 8:01 am

looks that way

#416 Postby **storms in NC** » Sat Aug 06, 2005 8:18 am

TD#9 is looking better all time now. See it can hold on to it

#417 Postby **EDR1222** » Sat Aug 06, 2005 8:19 am

According the 5 a.m. discussion, the forecast is complicated and depends on the intensity of the storm. Since it is fairly weak, it looks like it will keep moving more westward, at least in the short term. They did indicate in their discussion that the LLC is still well defined.

#418 Postby **Windtalker1** » Sat Aug 06, 2005 9:55 am

http://www.ssd.noaa.gov/PS/TROP/DATA/RT ... -loop.html Looking at the water vapor image, it seems as if the high to the north has started forcing TD9 on a more westerly track. The high seems to be building in very nicely. You can also see the convection now over what I am calling the new center of circulation...I may be wrong, I just taking a stab at this.....I am sure you will all tell me if I'm NUTS. :roll:

Josephine96 · #419 Postby **Josephine96** » Sat Aug 06, 2005 10:00 am

Wind.. you may be correct.. and BTW.. I'd never tell you you were nuts lol

clfenwi · #420 Postby **clfenwi** » Sat Aug 06, 2005 10:10 am

TD#9

Convection over LLC?

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