Invest 96L East of Windwards,Sat Pics,Analysis and Models

[Aric Dunn]

When its independent of the ITCZ, then it should be upgraded. Will it? No one knows, but it should be.

i would say if there is some more convection.. but there are some signs we could see another burst of convection here soon

[WeatherEmperor]

According to the maps i posted above windshear looks ok for future development.Different models point on a different outlook as far as shear is concerned.

In your opinion which model would you put the most faith in right now regarding the shear forecast, or is it too early to say for sure?

<RICKY>

[O Town]

Yo South,
None of the links you posted are working. You have to use the url tags in the new board. Just thought I would give you a heads up. Thanks.

[SouthFloridawx]

Yo South,
None of the links you posted are working. You have to use the url tags in the new board. Just thought I would give you a heads up. Thanks.

Ah crap... thanks, I'll repost.

[Tampa Bay Hurricane]

I don't expect shear to be much of a problem...the graphic posted on the previous
page showed low shear values...so low shear
But the issue will be can it hold up with the dry air...
someone pointed out earlier that the dry air may
be moving away...I do expect that this will
be declared a tropical depression by tomorrow..
In fact I personally think it is already a depression...
but sticking to the official source...I'd say by tomorrow
we have at least a depression...unless dry air
destroys it tonight...but I don't anticipate
signficant dry air intrusion.

[Berwick Bay]

According to the maps i posted above windshear looks ok for future development.Different models point on a different outlook as far as shear is concerned.


I believe windstorm?? wrote the above. And with that said, I wouldn't be too negative about future development assuming this thing is elevated to tropical cyclone status. I've seen nothing posted here (remember I'm just Joe Six Pack) which shows any unreasonable shear down the line. This system itself has battled some shear and dry air already to get where it is. I'll repeat that conditions are rarely perfect for development of tropical systems, yet many do so anyway. If this system is upgraded to cyclone, I would think that the best bet would be for a very slow, but steady development over the next 3 days or so.

[curtadams]

Still continues to look better, and I still feel convection will be increasing over the next few hours. Cloud cover in the northern half is on the increase. I said it a couple hours ago about it looking better, however, I was accused of looking at illusions and outflow boundaries LOL

A couple of hours ago it was mixed. The lower-level circulation was looking much better but the convection was looking much worse. I'd guess it was acting more like a subtropical system where convection away from the center can still strengthen it. Now it's acting tropical again.

Convection will indeed probably increase because we're passing the late afternoon diurnal minimum.

[cycloneye]

000
FXCA62 TJSJ 032048 CCA
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
441 PM AST TUE JUL 3 2007

.DISCUSSION...
DURING THE AFTERNOON...SKIES WERE MOSTLY SUNNY TO PARTLY CLOUDY
ACROSS THE EAST SECTIONS OF PUERTO RICO...CULEBRA...VIEQUES AND
THE U.S. VIRGIN ISLANDS. THE CENTRAL AND WEST INTERIOR SECTIONS OF
PUERTO RICO BECAME MOSTLY CLOUDY AS SHOWERS AND ISOLATED
THUNDERSTORMS DEVELOPED AND MOVED WESTWARD ACROSS THE SURROUNDING
MUNICIPALITIES. SOME OF THE STORMS PRODUCED LOCALLY HEAVY RAINFALL
WHICH LEAD TO LOCALIZED FLOODING IN THE WEST. THE GENERAL LOW LEVEL
WIND FLOW WAS FROM THE EAST...EXCEPT FOR LOCAL SEA BREEZE VARIATIONS
IN SOME AREAS.

SHOWERS AND THUNDERSTORM ACTIVITY WILL DIMINISH ACROSS THE LOCAL
ISLANDS DURING THE EVENING HOURS LEAVING CLEAR TO MAINLY PARTLY
CLOUDY SKIES. A WEAK LOW LEVEL TROUGH AND ASSOCIATED MOISTURE WILL
CONTINUE TO MOVE WEST ACROSS THE EASTERN CARIBBEAN DURING THE
OVERNIGHT HOURS. THIS WILL BRING PATCHES MOISTURE ACROSS THE
REGIONAL WATERS DURING THE OVERNIGHT HOURS. SOME OF THE SHOWERS
WILL REACH THE EAST COASTAL AREAS OF PUERTO RICO AND PARTS OF THE
U.S VIRGIN ISLANDS BUT NO SIGNIFICANT RAINFALL IS EXPECTED.

OVERALL FAIR WEATHER CONDITIONS ARE FORECAST FOR THE FOURTH OF
JULY...WITH ONLY SOME AFTERNOON SHOWERS IN THE WEST SECTIONS OF
THE PUERTO RICO. LATE WEDNESDAY THROUGH THURSDAY A TROPICAL WAVE
WILL MOVE ACROSS THE LOCAL AREA IN TANDEM WITH A TUTT NOW EAST OF
THE LESSER ANTILLES. THIS WILL BRING ADDITIONAL MOISTURE AND
THEREFORE INCREASE THE CHANCES FOR SHOWERS AND THUNDERSTORMS
ACROSS THE LOCAL ISLANDS.

LONG TERM...A LOW PRESSURE SYSTEM ASSOCIATED WITH A TROPICAL WAVE
NEAR 39 WEST CONTINUED TO SHOW WELL DEFINED CIRCULATION WITH A
NOTABLE INCREASE IN CONVECTION THROUGHOUT THE DAY. THIS SYSTEM
DOES HAVE POTENTIAL FOR SOME FURTHER DEVELOPMENT OVER THE NEXT DAY
OR SO...BUT AT THIS TIME LATEST MODEL GUIDANCE SUGGESTS THIS SYSTEM
TO MOVE OVER THE LOCAL AREA AS AN OPEN WAVE SUNDAY NIGHT THROUGH
MONDAY. FOR NOW WILL HAVE TO JUST MONITOR THIS SYSTEM OVER THE
NEXT FEW DAYS AND SEE HOW IT UNFOLDS. IN THE MEANTIME EXPECT AN
INCREASE MOISTURE ACROSS THE REGION SUNDAY NIGHT INTO MONDAY OF
NEXT WEEK

Here is what the NWS in San Juan is thinking at this time about the system.

[MiamiensisWx]

Still continues to look better, and I still feel convection will be increasing over the next few hours. Cloud cover in the northern half is on the increase. I said it a couple hours ago about it looking better, however, I was accused of looking at illusions and outflow boundaries LOL

I did not state that development was implausible... I think the system will gain further organization, but I believed it would happen over the next several days (not within the immediate term). I also noted that there were some pre-existant outflow boundaries within the SE quadrant, and the LLC was broad and diffuse at that time.

Lately, it appears that convective organization is improving as the sun sets. The diurnal convection appears to be clustering near the sfc low (low-level circulation). Low-level moisture may increase, and I have noticed some increasing instability. I tend to agree with your thoughts... I just wanted to clarify my position, so I apologize if you misread my original post.

[SouthFloridawx]

Looking at Mid-Level WV Imagery, it would appear that since the dry air that is to the north of the system is moving more quickly west than the system is. There is a decent area of moisture behind this system to the East, as Aric Pointed out.

http://cimss.ssec.wisc.edu/tropic/real-time/wavetrak/movies/m8wvmid/m8wvmidjava5.html

850-500mb Steering Layer...

If you associate that loop with this map, you can see that the area of dry air to the north is located in an area that is being pushed faster than, our system to the south.

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

In a couple of days our system should slow down a bit as the surface/mid-level ridge remains a bit stationary, as there is a Trough located off of the Mid Atl. and North East Coast of the US. This should break down the ridge a bit and slow down the system until the trough pulls out and the mid level ridge builds back in...

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/carib/gfs/12/index_slp_lu_loop.shtml
Since the system is located farther away from the Surface/Mid-Level Ridge, than it's enemy dry air, we'll probably see an increase in thunderstorm activity tonight and into tomorrow.

You can see this process already starting to happen on the vis. link I have posted below this comment. Notice as you can see more lower level clouds forming to the North and Northeast of the low pressure area, that there was earlier. If you want my two cents and it doesn't matter, I have seen this happen before, where a low pressure gets into a little more favorable environment and just explodes, creating and envelope of moisture around the center. I could be wrong, but I think this is what I see happening.

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

Links fixed... Thanks, "Otown"

[Aric Dunn]

I pretty sure the main inhibiting factor continues to be the last bit of attachment to the ITCZ which is probably not allowing for a complete wsw to sw inflow.. which would hold back and major t'storms development.. that combined the dry air to its north .. is why we have not seen a large burst of convection .. but that may change as the attachment seems to be fading!!

[philnyc]

I like your analysis, Miami. With a surface low now almost a done deal (tho may be more than 1 LLC), and with the diurnal min passing, we could see a pretty good convective flareup tonight. The 1015 TMI pass looked like it had winds of 30 knots. Seems like it's doing better than it should be, given the marginal conditions.

[Aric Dunn]

for instance ... this image compared to the one i posed on i think page 11 referencing the ITCZ on the microwave..



if you notice the bands that are forming on the west and wnw side of the circ.. as well as on the sw this are the typical problem areas.. but with the curved bands i believe that its almost free here a few more hours
oh and the last image was from a few hour ago verse just recently with this one

[Aric Dunn]

here is a wind estimate


as of 2000z

[Aric Dunn]

and actually the WV is not too bad in close proximity to the system ... there is plenty of moisture for a modest system to develop

[MGC]

Still a long shot IMO. System will have to have its convection better organized for this to be upgraded. It is working its way towards warmer waters though. It does look a bit better this afternoon. We shall see if this trend continues......MGC

[Berwick Bay]

MGC, really appreciate your insights and those of Tampa Bay Hurricane's and others in regard to this system. Very much appreciated here in this "talkin tropics' forum.

[cycloneye]

ABNT20 KNHC 032128
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
530 PM EDT TUE JUL 3 2007

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

A BROAD AREA OF LOW PRESSURE OVER THE CENTRAL ATLANTIC OCEAN IS
LOCATED ABOUT 1400 MILES EAST OF THE SOUTHERN WINDWARD ISLANDS.
ASSOCIATED SHOWER AND THUNDERSTORM ACTIVITY HAS DECREASED
TODAY...BUT IT IS STILL POSSIBLE THAT THIS SYSTEM COULD BECOME A
TROPICAL DEPRESSION WITHIN THE NEXT COUPLE OF DAYS AS IT MOVES
WESTWARD AT 10 TO 15 MPH.

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

$$
FORECASTER KNABB/LANDSEA

[Aric Dunn]

another thing .. we have not quite meet the requirements of a TCFA yet..... http://www.nlmoc.navy.mil/trg/tropical/ ... cklist.htm

those requirements are very simple.. i dont think they follow that very closely but its a good thing to remember.. when we have systems like this ...

[philnyc]