ATL: INVEST (97L)

[Ed Mahmoud]

Looks good, obvious mid level rotation but my super close up loop shows it barfed a couple of outflow boundaries out to the West about 2 hours ago.

[Dean4Storms]

It has all the looks this morning of a TD as far as one can tell by Sat. pics, would be nice to have some surface obs by some ships out there! I think NHC goes to code orange at 2pm, but this could get upgraded if this trend continues all day.

[Ed Mahmoud]

The main vorticity with 97L is in the Southern GOMEX, barely perceptible per Canadian.

The Carolina hurricane is either the extreme North end of the 97L wave or the preceding wave.

[senorpepr]

I just ran the TCFA checklist on 97L. Still too low to consider, but it's improving.

[Aric Dunn]

I just ran the TCFA checklist on 97L. Still too low to consider, but it's improving.

hey you have the numbers for that.. ?

i mean i have the checklist .. but the criteria numbers for adding everything is missing .. you have it ?

[Ed Mahmoud]

It has all the looks this morning of a TD as far as one can tell by Sat. pics, would be nice to have some surface obs by some ships out there! I think NHC goes to code orange at 2pm, but this could get upgraded if this trend continues all day.

Hmmm, it would be tricky now getting a plane positioned to St Croix, then fly this system tomorrow, which would ensure adequate lead time for a watch for Barbados if this developed. Maybe a resources permitting misison with 2 crews, one sleeping during the transit.

97L looks like it is pushing a bit of outflow into the TUTT, and if it can get a piece of the TUTT to pinch off, then travel ahead of it, it would do wonders for the outflow.

If the trough stays there, WxMan57's prognosis seems likely.


BTW, Canadian has a hurricane near Hatteras in 5 days (see model thread), but not entirely certain from tracking 850 mb vorticity if it is 97L or not. If it is, it is 97L's parent wave, but not 97L.

[lester]

so did 97L get reactivated? i've been living under a rock for the past 12 hours..

[StormTracker]

The big picture...



OR:

http://rammb.cira.colostate.edu/products/tc_realtime/16kmgwvp_loop.asp?storm_identifier=AL972009&starting_image=2009AL97_16KMGWVP_200907171815.GIF

[Ivanhater]

Looks good now but I doubt it will hold for another day

[Dean4Storms]

It is close. You can see the outflows Ed alludes to but the cumulus at the southern extent of the outflows appear to be getting pulled SSE (Arching) as if into a circulation close to the surface.

[bvigal]

It has all the looks this morning of a TD as far as one can tell by Sat. pics, would be nice to have some surface obs by some ships out there! I think NHC goes to code orange at 2pm, but this could get upgraded if this trend continues all day.

ID T1 TIME LAT LON WDIR WSPD GST WVHT DPD APD MWD PRES PTDY ATMP WTMP
(GMT) °T kts kts ft sec sec °T in in °F °F °F nmi 8th ft ft
SHIP S 1600 8.00 -53.10 200 8.9 - 3.3 12.0 - - 29.97 +0.03 84.2 84.2 - 5 6 -

[senorpepr]

Hmmm, it would be tricky now getting a plane positioned to St Croix, then fly this system tomorrow, which would ensure adequate lead time for a watch for Barbados if this developed. Maybe a resources permitting misison with 2 crews, one sleeping during the transit.

Interestingly... AF306 appears to have been at St. Croix, but they took off this morning and at last report (1649Z) they were over the SE Bahamas.

[cycloneye]

Code Yellow

191
ABNT20 KNHC 191732
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT SUN JUL 19 2009

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

SHOWER AND THUNDERSTORM ACTIVITY ASSOCIATED WITH A TROPICAL WAVE
LOCATED ABOUT 600 MILES EAST OF THE WINDWARD ISLANDS HAS BECOME
BETTER ORGANIZED OVER THE PAST SEVERAL HOURS. WHILE ENVIRONMENTAL
CONDITIONS ARE CURRENTLY FAVORABLE FOR SOME DEVELOPMENT OF THIS
SYSTEM...UPPER-LEVEL WINDS ARE EXPECTED TO BECOME LESS FAVORABLE
TONIGHT. REGARDLESS OF DEVELOPMENT...LOCALLY HEAVY RAINFALL AND
GUSTY WINDS COULD AFFECT THE WINDWARD ISLANDS ON MONDAY AS THE WAVE
MOVES WESTWARD AT 15 TO 20 MPH. THERE IS A LOW CHANCE...LESS THAN
30 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER BRENNAN/BLAKE

[KWT]

Looks to me like its at least a code orange now, though as has been said its still not quite there yet.

Still it has got a little bit of time before shear increases. I think we may get a TD briefly out of this before shear kills it off again, but I think downstream if it can get into a pocket of lower shear in about 4-5 days time near the Carolinas it has a shot at strengthening again. We shall see!

[Aric Dunn]

hahah.. that was a funny outlook.. it was like dont bother me right now you pesky 97L

[Aric Dunn]

Looks to me like its at least a code orange now, though as has been said its still not quite there yet.

Still it has got a little bit of time before shear increases. I think we may get a TD briefly out of this before shear kills it off again, but I think downstream if it can get into a pocket of lower shear in about 4-5 days time near the Carolinas it has a shot at strengthening again. We shall see!

I highly doubt its going north .. but will see.. especially if it stays weak.. the before it is still heading west and is south of Hispaniola the ridge is still holding strong. also the shear is forecast after 24 hours in the central carrib to be much more favorable than now.

[Sanibel]

Goes to show that 'spin' is the strongest and most meaningful feature of a wave. I thought this one was finished yesterday but the spin was the telling indicator and it reconvected further west as some mid-Atlantic subsidence-weakened waves do at this time.

I guess it has gotten over the hardest part and should form.

[KWT]

I highly doubt its going north .. but will see.. especially if it stays weak.. the before it is still heading west and is south of Hispaniola the ridge is still holding strong. also the shear is forecast after 24 hours in the central carrib to be much more favorable than now.

The southern part of the wave will carry on westwards but I think the wave will quite possibly split, we shall see. The conditions are better for the southern portion of the wave but the models aren't developing that area at all. The further south 97L stays though the better the chances and as you say if 97L did get into the caribbean conditions are not that bad.

[Aric Dunn]

I highly doubt its going north .. but will see.. especially if it stays weak.. the before it is still heading west and is south of Hispaniola the ridge is still holding strong. also the shear is forecast after 24 hours in the central carrib to be much more favorable than now.

The southern part of the wave will carry on westwards but I think the wave will quite possibly split, we shall see. The conditions are better for the southern portion of the wave but the models aren't developing that area at all. The further south 97L stays though the better the chances and as you say if 97L did get into the caribbean conditions are not that bad.

ummm.... we have a devloping system they just dont split like that.. also its typically the greater Antilles that ultimately splits the waves this is is farther south than the previous one ( which did split but most of the energy is south of hispanola), the ridge to the north is still in place this most likely will stay in carrib to at least the central carrib before some real northerly components take shape.. even if it deepens to TD the deep layer flow is still pretty much west ..

[Sanibel]

If I were to judge by visible floater loop dvorak, curvature, convection, inflow, and outflow I would say absolutely no doubt about this being the first system. It will be interesting to see if it doesn't form and why.