Tropical Depression TEN: Discussions & Images

[PhillyWX]

Right...and I will reiterate what I said last night. The real key to all of this is actually the longwave out west digging down into CA. How that digs down will determine how the rest of this plays out...and whether south/central TX gets a major or AL/MS get a strong TS/cat 1.

I agree with this 100%. That trough is the key in all of where this system goes....analysis like this is what is critical in following...it's not just reading what a model says but one has to look upstream and realize that small changes upstream = big changes downstream.

[Steve]

>>Right...and I will reiterate what I said last night. The real key to all of this is actually the longwave out west digging down into CA. How that digs down will determine how the rest of this plays out...and whether south/central TX gets a major or AL/MS get a strong TS/cat 1.

Also understood. That longwave in CA would seem to indicate western troughiness and warmer weather in the eastern US/high pressure. If it digs and holds in the west, I think that's a sure sign fall is still a ways off for the southern tier of states (Central Texas eastward) and a prolonged opportunity for Florida or Gulf threats at least until it lifts out or migrates eastward. Obviously that's something I want to watch, because it's been my opinion from the genesis of Humberto, that the prime US landfalling season was commencing. If that trough stays out west for say 3 weeks, I could easily see 3 threats to Florida and/or the Gulf Coast.

That's when it's time to break out the



Steve

[GeneratorPower]

AFM, it looks pretty good on IR4 loop. Is this going to last or is there something driving this convection that will dissipate?

[MiamiensisWx]

I hope this doesn't qualify as chat. I tried to post my analyses, but they were overshadowed by one-liners.

It looks like we may receive a TD/STD classification later today, especially based on the defined LLC, wind reports (gradient enhanced), and other data + improving satellite signature and radar imagery. I have an uncanny feeling that the TPC will not hold off an upgrade when data is analyzed. They will wait over the next several hours for persistence, but the latest convective burst (over the circulation) may pull the trigger tonight. It is clearly an evolving "entity", IMO. Thunderstorm activity is steadily increasing around the broad circulation.

http://www.ssd.noaa.gov/goes/east/gmex/loop-avn.html

http://weather.cod.edu/analysis/loops/satmaster.pl?Carribbean

http://rammb.cira.colostate.edu/ramsdis/online/loop_640.asp?product=tropical_ge_4km_visir2_floater_1

http://www.srh.weather.gov/ridge/lite/N0R/AMX_loop.gif

The upper low appears to be moving W, thus providing the initial baroclinic "spark" for a sfc low. The movement of this upper low may reflect the upper-air pattern and influence 93L's motion. If 93L moves closer to the upper low, it will encounter the stronger shear. If 93L's broad circulation lingers over the next several hours, it could organize, albeit at a slow pace because of shear (although it is relaxing). It looks like any S component will be short-lived, and we should see a general W trend toward the FL peninsula:

http://rammb.cira.colostate.edu/ramsdis/online/loop_640.asp?product=tropical_ge_14km_wv

700-850 mbar heights:

http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/winds/wg8dlm1.html

500 mbar heights:

http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/winds/wg8dlm2.html

I think a STDS (possible upgrade) will be issued tonight if trends persist over the next several hours.

[skysummit]

Countdown to the EURO....appx 38 minutes

[Brent]

I hope this doesn't qualify as chat. I tried to post my analyses, but they were overshadowed by one-liners.

It looks like we may receive a TD/STD classification later today, especially based on the defined LLC, wind reports (gradient enhanced), and other data + improving satellite signature and radar imagery. I have an uncanny feeling that the TPC will not hold off an upgrade when data is analyzed. They will wait over the next several hours for persistence, but the latest convective burst (over the circulation) may pull the trigger tonight. It is clearly an evolving "entity", IMO. Thunderstorm activity is steadily increasing around the broad circulation.

http://www.ssd.noaa.gov/goes/east/gmex/loop-avn.html

http://weather.cod.edu/analysis/loops/satmaster.pl?Carribbean

http://rammb.cira.colostate.edu/ramsdis/online/loop_640.asp?product=tropical_ge_4km_visir2_floater_1

http://www.srh.weather.gov/ridge/lite/N0R/AMX_loop.gif

The upper low appears to be moving W, thus providing the initial baroclinic "spark" for a sfc low. The movement of this upper low may reflect the upper-air pattern and influence 93L's motion. If 93L moves closer to the upper low, it will encounter the stronger shear. If 93L's broad circulation lingers over the next several hours, it could organize, albeit at a slow pace because of shear (although it is relaxing). It looks like any S component will be short-lived, and we should see a general W trend toward the FL peninsula:

http://rammb.cira.colostate.edu/ramsdis/online/loop_640.asp?product=tropical_ge_14km_wv

700-850 mbar heights:

http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/winds/wg8dlm1.html

500 mbar heights:

http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/winds/wg8dlm2.html

I think a STDS (possible upgrade) will be issued tonight if trends persist over the next several hours.

I agree with this. I would not be surprised at all see to see a TD or TS before FL landfall. The 18z models have the intensity up to 25 kt.

[Air Force Met]

>>Right...and I will reiterate what I said last night. The real key to all of this is actually the longwave out west digging down into CA. How that digs down will determine how the rest of this plays out...and whether south/central TX gets a major or AL/MS get a strong TS/cat 1.

Also understood. That longwave in CA would seem to indicate western troughiness and warmer weather in the eastern US/high pressure. If it digs and holds in the west, I think that's a sure sign fall is still a ways off for the southern tier of states (Central Texas eastward) and a prolonged opportunity for Florida or Gulf threats at least until it lifts out or migrates eastward. Obviously that's something I want to watch, because it's been my opinion from the genesis of Humberto, that the prime US landfalling season was commencing. If that trough stays out west for say 3 weeks, I could easily see 3 threats to Florida and/or the Gulf Coast.

That's when it's time to break out the



Steve

And that is what the 12z run of the GFS is doing...lifting it out. I am not so sure this will happen. This is starting to be the time of year for the cutoff low in the SW US. The GFS always likes to see a progressive trof and doesn't like to cutoff lows...so it will be interesting to see if this low does cut off and dig. The earlier runs had it doing so...but now that the GFS is in the mid-range...day 4/5...it is pulling it out to the NE (the cut off low).

I tend to think it will dig a little deeper than the GFS is forecasting...and maybe even cut-off around day 5.

[duris]

What sort of forward speed or precipitation totals do the models predict (if they predict such a thing)? The reason I ask is that the GFDL and GFS tracks west of New Orleans might be bad if this is a slow moving rain producer. From what I've gleaned from the discussion, its not going to be a slow mover but just wondering.

[whereverwx]

Not too significant, but here's a loop, anyway.

[Tampa Bay Hurricane]

Florida may get about 5 inches of rain in some places
even if it moves quickly.

ULL is moving away from this into a position to enhance this system.

The center of circulation is moving East,
giving it more time to intensify. Oceanic
heat content in the gulf stream is explosive- as winds went from nothing to 39 mph gusts in the bahamas in just a few hours- a sign of rapid
intensification. Shear is dropping very fast
from 30 kts to 20 and soon 10-15 kts or less.
I see a good chance of rapid intensification to a 50 mph tropical storm prior to landfall in SE
florida.

[AJC3]

Thanks. But I already credited you for that in my comments . I didn't so much see the baroclinic forcing, you guys did. I knew there would be some resolution with all the ingredients coming in, but I figured the transition would be more tropical at first due to the wave's interaction rather than a phase (btw, what's the appropriate term for a reverse-phase when something goes tropical from nontropical?).

Steve

What I was looking at was the upper level pattern and the fact the models were putting down a low. The only thing that made sense to me was baroclinic forcing. If you look at the low now...it is being formed under a huge area of divergence aloft...not only directional but speed divergence. The divergence in direction is almost 90 degrees and the speed divergence is also kicking. It had no choice but to develop something at the sfc. But...it will remain sheared for a few days because as you can see in the WV loop...it is an impressive upper low. As I mentioned last night...it reminds me of something you see in the western Gulf....nice sfc low with everything on the north and east side. The only question remaining is what becomes of the upper pattern latter in the week over the gulf.

The RUC analysis fields have some of the highest H25 divergence values and H70 omega fields off the Florida east coast than I've seen down here in a long time. I think my message to those who don't quite understand baroclinc (non-tropical) cyclogenesis would be this: The surface low isn't forming in spite of the UL shear from strong winds on the east side of the low...it's forming because of the very strong UL divergence from those winds.

[jwayne]

>>Right...and I will reiterate what I said last night. The real key to all of this is actually the longwave out west digging down into CA. How that digs down will determine how the rest of this plays out...and whether south/central TX gets a major or AL/MS get a strong TS/cat 1.

Also understood. That longwave in CA would seem to indicate western troughiness and warmer weather in the eastern US/high pressure. If it digs and holds in the west, I think that's a sure sign fall is still a ways off for the southern tier of states (Central Texas eastward) and a prolonged opportunity for Florida or Gulf threats at least until it lifts out or migrates eastward. Obviously that's something I want to watch, because it's been my opinion from the genesis of Humberto, that the prime US landfalling season was commencing. If that trough stays out west for say 3 weeks, I could easily see 3 threats to Florida and/or the Gulf Coast.

That's when it's time to break out the



Steve

And that is what the 12z run of the GFS is doing...lifting it out. I am not so sure this will happen. This is starting to be the time of year for the cutoff low in the SW US. The GFS always likes to see a progressive trof and doesn't like to cutoff lows...so it will be interesting to see if this low does cut off and dig. The earlier runs had it doing so...but now that the GFS is in the mid-range...day 4/5...it is pulling it out to the NE (the cut off low).

I tend to think it will dig a little deeper than the GFS is forecasting...and maybe even cut-off around day 5.

AFM:

What would this mean in terms of likely effects on the track of storm?

[wxman57]

12Z EC says Freeport, TX mid to late morning Sunday. I have it plotted with 1/2 mb contours. A bit north of earlier runs. Making the upper TX coast to LA the target for now.

[Air Force Met]

Warning-Need DSL/Cable...

Hi-Res Loop

[cycloneye]

The LATEST at 18:45 UTC

[Air Force Met]

AFM:

What would this mean in terms of likely effects on the track of storm?

A deeper, less progressive trof will build the ridge stronger in the east...which will move this system more to the west. A more progressive trof in the west means a weaker ridge in the east and therefore the central gulf states are more at risk, although from a weaker system (unless the upper level winds change...which is possible).

[skysummit]

12Z EC says Freeport, TX mid to late morning Sunday. I have it plotted with 1/2 mb contours. A bit north of earlier runs. Making the upper TX coast to LA the target for now.

What is the "EC"? Are you talking about the ECMWF? I don't see the 12z on their site yet if so....or, are you plotting raw data.

[Evil Jeremy]

That's whats left of Ingrid, cycloneye

[Steve]

Thanks ajc and AFM.

>>And that is what the 12z run of the GFS is doing...lifting it out. I am not so sure this will happen. This is starting to be the time of year for the cutoff low in the SW US. The GFS always likes to see a progressive trof and doesn't like to cutoff lows...so it will be interesting to see if this low does cut off and dig. The earlier runs had it doing so...but now that the GFS is in the mid-range...day 4/5...it is pulling it out to the NE (the cut off low).

Yeah, seems like it always wants to move those things, but even if it was right and it lifted out, that would still indicate mostly higher pressure in the southeast and somewhat confirming my suspicion that the season cancel threads are going to be few and far between for a while.

Miami,

Thanks for the post. I ran the color watervapor loop, and I don't think I've ever seen dark reds that are showing up from South Carolina along the western periphery of 93L back toward Tampa. Is that ultra-dry air or is it something else? Sorry to seem like I don't know what I'm looking at there, but that really looks like desert dry if I'm reading it right. Your comments are appreciated as I didn't see a key for that WV loop. Thanks.

http://rammb.cira.colostate.edu/ramsdis ... ge_14km_wv
Steve

[Evil Jeremy]

also, the so called "eye" on the Miami radar is collapsing!!