Invest 90L: East Atlantic-Discussions,Analysis,Sat Pics

[Aquawind]

Buoy has wind shift to the ssw..notice the approach had N winds and with its passage the wind shift. There's def an LLC

Combined with QSCAT and visuals the NHC could call it at any time.

[Vortex]

H-168 nearing DR


http://www.nco.ncep.noaa.gov/pmb/nwprod ... n_168l.gif

[punkyg]

Aquawind are you luis? the people keeping talking too.

[WindRunner]

A quick run-through of the models on this system (or at least how they appeared at 00z before I left this morning) . . . even though 00z models have probably already been discussed already . . .


ECMWF is starting to realize that this is not the perfect situation . . . and is now adjusting its forecast accordingly. While both the GFS and CMC take this into the northern Caribbean at <1000mb around the day 6/7 time frame, the Euro instead opts for a weaker and more northerly track to a couple hundred miles NW of the Turks and Caicos by day 8. Upon further inspection of the GFS, the Euro seems to be a more sane option at this point. The GFS has an upper low drop southward just behind the cyclone as it passes 40W, and the trough coming off the East Coast now just misses the cyclone to the east about a day later . . . two awfully close (and awfully lucky) occurances. And of course if the negative upper level features are completely avoided, the environment is otherwise favorable . . . leading the GFS to really go wild with this system before it hits the islands. For example, the HWRF (based off the GFS) has a TS at 12z today, a hurricane by 06z Wednesday morning, and starts bombing it out beyond 114 hours (MSLP 960mb/100kts) through the end of the run at 126 hours (MSLP 948mb/110kts), at which point it is slightly northeast of the corresponding GFS position. Needless to say, as much as I'm sure some people would love to see it happen, the GFS and all related solution seem somewhat unreliable at this point . . . and until the storm gets going, similar idealized scenarios will be both commonplace and wrong.


Key feature to watch: Ridge over the southeast in the day 7-10 range (and associated weakness to the east) as that will be our main steering feature once it nears land.

OK, in a quick look at these two, I woud argue that the GFS even places the upper low in a perfect spot for intensification--it sits right where it needs to in order to provide an outflow channel for the system in the mid-atlantic. I used the Penn State e-wall for the euro and it did not seem to see that upper low (hard to tell becasue the 4 panels really aren't helpful there). As such, the aggressive outflow did not exist, and the system seemed weaker.

The GFS seems to have it miss the trough because the GFS is faster than the Euro with the system--the system is west of (and a bit south of) where it needs to be for the trough to get it in the GFS. So I think there's a forward speed issue at play too.

WJS3

Yeah, basically the GFS has set things up perfectly for a storm to "speed," if you will, westward into the NW Carib at a decent intensity. I believe long-range GFS even takes it into Tampico this run (00z) as a decent-strength system. It's just too perfect of a track to actually verify the track itself or the associated intensity . . . So, until we can get some good continuity on one of these solutions, or even model agreement on each run, the track beyond 50/55W is still very much up in the air.

[Vortex]

H-180 Landfall Jamaica


http://www.nco.ncep.noaa.gov/pmb/nwprod ... n_180l.gif

[Vortex]

I agree with you windrunner....

[Aquawind]

Aquawind are you luis? the people keeping talking too.

Nope that is cycloneye.

[Vortex]

H-216 Yucatan Landfall


http://www.nco.ncep.noaa.gov/pmb/nwprod ... n_216l.gif

[punkyg]

from the model Vortex keep posting.
it looks like it might make it to the gulf.

[Vortex]

H-264 Final Destination Old mexico


http://www.nco.ncep.noaa.gov/pmb/nwprod ... n_264l.gif

[punkyg]

Is there any new pictures of 90L.

[Meso]

..SPECIAL FEATURE...
A VIGOROUS TROPICAL WAVE IS LOCATED OVER THE FAR EASTERN ATLANTIC
OCEAN ALONG 22W S OF 19N. A 1006 MB LOW PRES IS NEAR 12N22W OR
ABOUT 300 MILES SOUTHEAST OF THE SOUTHERNMOST CAPE VERDE
ISLANDS. SHOWERS AND THUNDERSTORMS HAVE CHANGED LITTLE IN
ORGANIZATION OVERNIGHT. HOWEVER...CONDITIONS APPEAR FAVORABLE
FOR GRADUAL DEVELOPMENT OF THIS SYSTEM...AND A TROPICAL
DEPRESSION COULD FORM DURING THE NEXT DAY OR TWO AS IT MOVES
WESTWARD AT 15 TO 20 MPH. MODERATE TO ISOLATED STRONG CONVECTION
IS WITHIN 60NM OF 12N24W.

[wxman57]

Looks better-organized this morning. I think the main question is when the NHC will feel like upgrading it. I don't know who's working nights at NHC, but I've noticed a lack of continuity between night and day shifts. Night shift will say "no development next 48 hours", day shift will discuss two significant areas of concern. Last night's shift downplayed development potential. What will the day shift bring? I think it's pretty clearly a tropical depression now, though I'd like to see some good visible imagery before being sure. I think the NHC will just watch it today. They MAY decide to upgrade it this afternoon (again, depends on who's working, I guess). More likely tomorrow, though.

I'm heading into the office shortly, can look at it there. Oh, and notice that the 00Z GFS brought it to Mexico in 11 days, and the 06Z GFS couldn't find it at all?

[cycloneye]

LOOKING AHEAD...THIS PORTION OF THE FORECAST IS STILL MANY DAYS
AWAY AND IS SUBJECT TO SIGNIFICANT CHANGES AND ERRORS. THIS
FOLLOWING DISCUSSION IS MEANT ONLY AS A GENERAL OUTLOOK OF
POTENTIAL FEATURES.

HOWEVER...THAT SAID...A VIGOROUS AND FAIRLY WELL ORGANIZED
TROPICAL WAVE/LOW CURRENTLY LOCATED ABOUT 300 MILES
SOUTH-SOUTHEAST OF THE SOUTHERNMOST CAPE VERDE ISLANDS IS BEING
MONITORED AND PER TPC/NHC...COULD BECOME A TROPICAL DEPRESSION
DURING THE NEXT DAY OR TWO AS IT MOVES WESTWARD AT 15 TO 20 MPH.

INTERESTINGLY...THIS FEATURE HAS BEEN FORECAST WITH AMAZING
CONSISTENCY NOW FOR 6 DAYS AND BASICALLY 24 CYCLES OF THE GFS
MODEL...TO BECOME MORE ORGANIZED AND STRENGTHEN INTO WHAT...
POTENTIALLY...COULD BECOME A RATHER IMPRESSIVE TROPICAL CYCLONE AS
IT MOVES WEST TO WEST NORTHWEST ACROSS THE ATLANTIC AND IN THE
GENERAL DIRECTION OF THE EAST AND/OR NORTHEAST CARIBBEAN BY LATE
THIS COMING WEEK OR EARLY NEXT WEEKEND. THE GFS MODEL HAS ALSO
BEEN JOINED BY THE UKMET...CANADIAN...ECMWF AND WRF MODELS IN
INDICATING THE SAME GENERAL IDEA...AGAIN WITH DECENT CONSISTENCY
AND SIMILARITY. SO...ALTHOUGH THERE IS STILL TREMENDOUS
UNCERTAINTY AND REALIZING THAT CURRENTLY THIS FEATURE IS STILL
ONLY A TROPICAL WAVE/LOW AND STILL MANY DAYS AWAY...IT WOULD BE
PRUDENT FOR ALL LOCAL RESIDENTS AND VISITORS OF THE U.S. VIRGIN
ISLANDS AND PUERTO RICO TO MONITOR LOCAL WEATHER FORECASTS DURING
THE NEXT SEVERAL DAYS.



The above from the San Juan NWS discussion this morning.

[bvigal]

wxman, I got an sudden warm and fuzzy feeling reading your post... it's good to know that you and others here, armed with experience and knowledge, are keeping an eye on this. Thanks!

[skysummit]

wxman, I got an sudden warm and fuzzy feeling reading your post... it's good to know that you and others here, armed with experience and knowledge, are keeping an eye on this. Thanks!

Yea, but the only problem I had with that post was him saying the 06z GFS couldn't find it at all.

Here's the 06z GFS showing it entering the Caribbean @ 126 hours:

[Steve]

>>This is an excellent and thoughtful piece of analysis. Thanks for taking the time to do it. I haven't compared the GFS and Euro runs yet, but will now.

I usually go with the European as well, and I certainly don't do so based on where I live. It just handles the west Atlantic better. Having said that, look at JTWC's track for TD #9.

https://metocph.nmci.navy.mil/jtwc/warnings/wp0907.gif

Should it continue to evolve as a west mover or even WNW toward Taiwan, 90L is not going to be a mid-Atlantic threat.

Steve

[cycloneye]

Impressive recent visible image of 90L.It looks like almost a TD or one now.

[cycloneye]

A Tropical Cyclone Formation Alert has been issued.But as NRL is out the text is not found.

[Chacor]

AL, 90, 2007081212, , BEST, 0, 123N, 243W, 25, 1008, DB, 34, NEQ, 0, 0, 0, 0, 1011, 150, 35, 0, 0, L, 0, , 0, 0, INVEST, M,

ATCF says it has weakened slightly (0600 UTC pressure was 1007).