TC Bertha

[Aric Dunn]

check out the last 2 images.. only 30 minutes apart.. we are the verge of a large burst..





convection firing right over the apparent center...

[jrod]

What a way to start July! Once again my co-workers are going to think I am crazy for how much I care about the tropics this time. Even if this doesn't develop, as far as I am concerned the season is on.

[wxman57]

Convection does appear to be on the increase now, but I think the NHC will give it 24-48 hours before jumping on it. No need to act too quickly with it barely off the coast of Africa and likely no threat to any land areas with the possible exception of some heavy rain in the southern Cape Verde Islands.

I suppose I'll need to put together a work schedule for the team for the 4th of July weekend. Was hoping to have a few days to relax here with the wife out of town visiting her family. Now I'll have to be looking over my shoulder at 92L or Bertha.

[canegrl04]

Bertha is going to be the first shot across the bough for the season

[Eyewall]

IIRC there was a user named The Great One long ago who acted ridiculously

hahah ohh well i was just refering to the 20-50% on the chart from the NHC. I guess "code" wasnt nessesary

[MiamiensisWx]

I have rescinded my previous decision and I will resume posting here. I still don't believe it will develop (per my latest analysis), but the challenges of forecasting are manifesting themselves in this situation.

However, if current trends continue over the next several hours, I believe we have a very decent chance of witnessing our second tropical cyclone of the season. A brief TD or TS classification can't be immediately ruled out.


http://climateprogress.org/wp-content/uploads/2008/05/polar-bear-tongue.jpeg

...A BEAR WATCH HAS BEEN OFFICIALLY DECLARED FOR THE EASTERN TROPICAL ATLANTIC...

[Aric Dunn]

00z IR

[Mecklenburg]

It looks like it's gonna develop soon

[MiamiensisWx]

In regards to the possible path, the strong subtropical ridging at 700-850 mb may result in a movement slightly further south than the majority of the model guidance. It is very early in the potential "life span" of this system, and it is difficult to place undue weight into the models until we have a defined low level circulation. Currently, there is an area of low pressure at the surface, and we undoubtedly have a weak surface low, but there is no evident LLC. Overall, it is objective to avoid placing trust into the intensities progged by the SHIP et al, as well as the model "clusters" in regards to the track. You simply cannot trust any prognostications. The one tidbit that I will denote is the possible slight bias toward a more rapid NW turn. If the system deepens more rapidly, it will likely be influenced by the upper low that is currently located well NE of the Leeward Islands. Therefore, in that case, the northward solution is more palpable and plausible. However, if intensification is slower (as I anticipate), a more westerly path of the surface low may easily occur in reality, since the low level steering would support that scenario.

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

[Aric Dunn]

In regards to the possible path, the strong subtropical ridging at 700-850 mb may result in a movement slightly further south than the majority of the model guidance. It is very early in the potential "life span" of this system, and it is difficult to place undue weight into the models until we have a defined low level circulation. Currently, there is an area of low pressure at the surface, and we undoubtedly have a weak surface low, but there is no evident LLC. Overall, it is objective to avoid placing trust into the intensities progged by the SHIP et al, as well as the model "clusters" in regards to the track. You simply cannot trust any prognostications. The one tidbit that I will denote is the possible slight bias toward a more rapid NW turn. If the system deepens more rapidly, it will likely be influenced by the upper low that is currently located well NE of the Leeward Islands. Therefore, in that case, the northward solution is more palpable and plausible. However, if intensification is slower (as I anticipate), a more westerly path of the surface low may easily occur in reality, since the low level steering would support that scenario.

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

agreed it all depends on how deep the system becomes and how fast..

[RL3AO]

Miami, where is this weakness that the models keep seeing, or is it turning north in the models because of the strengthening and getting affected by the ULL you mentioned?

[MiamiensisWx]

Miami, where is this weakness that the models keep seeing, or is it turning north in the models because of the strengthening and getting affected by the ULL you mentioned?

In essence, the bolded portion is correct. The models' output are indicating a faster rate of intensification and greater interaction with the upper low, inducing a more northerly/NW movement. The upper low is clearly evident in the streamline analysis at 400-850 mb.

http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/winds/wg8dlm3.html

[Jason_B]

Is that ball of convection over Africa associated with 92L or something else?

[MiamiensisWx]

Is that ball of convection over Africa associated with 92L or something else?

The convection is likely aided by residual outflow boundaries, localized low level convergence, and low level vorticity in the region. This is partially because of the surface low (92L) off the coast and an approaching tropical wave axis to the east. There is also some ascent in the immediate vicinity as well. Overall, these inland thunderstorms will likely dissipate within the near future, in my view.

[cycloneye]

I think that the ssd T numbers for 92L has not been posted so here they are.

02/0000 UTC 11.9N 19.4W T1.0/1.0 92L -- Atlantic Ocean

[Eyewall]

Is that ball of convection over Africa associated with 92L or something else?

Based on the IR images before the convection fired, it looks like a small MLC maybe interacting with outflow boundries from 92L and some daytime heating

[MiamiensisWx]

Based on current movement, the strength of the low level ridging, and extrapolation, it appears that the broad, weak surface low will pass just south of the Cape Verde islands.

http://oiswww.eumetsat.org/SDDI/html/images/out/SDDI-20080702-0030-MPEF-09-MPE-04-1237.jpg

[gatorcane]

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org For Official Information please refer to the NHC and NWS products.

I've been reading through the last several hours of post. I'm still going with my forecast from earlier today. I really don't see rapid intensification as shown by SHIPs. I expect possible slow development, if any, with a marked decrease in convection coverage as it heads west.

You really have to look at the SSTs ahead of the system. While they are high just off Africa, they do cool as you go west. Consequently I don't see this system rapidly intensifying. I don't see any NW turn at all. Just a west to west southwest course initially followed by a west to WNW course as the system remains at strong tropical wave with an attached low or a depression.

and SAL is another issue in this thing's path. It should help decrease the convection as well. If it goes poof by the time it hits those slightly lower SSTs it really would not surprise me although I am expecting at most a depression moving westbound for the next several days.

[MiamiensisWx]

I've been reading through the last several hours of post. I'm still going with my forecast from earlier today. I really don't see rapid intensification as shown by SHIPs. I expect possible slow development, if any, with a marked decrease in convection coverage as it heads west.

You really have to look at the SSTs ahead of the system. While they are high just off Africa, they do cool as you go west. Consequently I don't see this system rapidly intensifying. I don't see any NW turn at all. Just a west to west southwest course initially followed by a west to WNW course as the system remains at strong tropical wave with an attached low or a depression.

and SAL is another issue in this thing's path. It should help decrease the convection as well. If it goes poof by the time it hits those slightly lower SSTs it really would not surprise me although I am expecting at most a depression moving westbound for the next several days.

The following post is NOT an official prognosis.

I concur with the bolded portion. I also believe that the deepening trend will be slower than depicted by the SHIP. Here is my strictly unofficial analysis from my site.

"It is becoming increasingly evident that some models are exhibiting a glaring bias toward a pattern change in the medium to long term. A pertinent paragraph from the NWS Miami WFO discussion tells the story. Originally, the longwave trough in the East was progged to "lift out" as early as Thursday. However, as evident in recent discussions, the timing has been repeatedly pushed further back by the models, including the operational GFS and others. This is becoming a "rinse and repeat" process, so I believe the trough will still be present through the weekened because of the relatively persistent/stagnant CONUS pattern.

.LONG TERM...SATURDAY THROUGH TUESDAY...CONDITIONS WILL START TO
SHIFT THROUGH THIS PERIOD AS THE LONG WAVE TROUGH IS REPLACED BY A
DEEP LAYER DEVELOPING RIDGE. NOT ONLY THE AMOUNT OF AVAILABLE
MOISTURE WILL DIMINISH SLIGHTLY, BUT ALSO THE LOCAL AREA WILL BE
UNDER DEEPER EASTERLIES AND SO THE STEERING FLOW WILL RESULT IN
AFTERNOON CONVECTION CONCENTRATING MORE OVER INTERIOR AND WEST
COAST.

Miami NWS WFO Area Forecast Discussion

Therefore, I'm inclined to believe that the Atlantic basin upper air set-up will remain relatively similar, with a strong Azores/subtropical ridge remaining in place. The upper low NE of the Leeward Islands will continue to induce strong upper level divergence east of the Lesser Antilles. As the surface low associated with the system moves further west, it will eventually encounter the stronger shear. When combined with the 700 mb temp inversion, SAL, and some low level dust (per visible satellite data) moving in tandem with the system, this will likely halt or kill its cyclogenesis probabilities. I agree that the EPAC and W Atlantic/Gulf of Mexico are the only mildly interesting areas, especially if the remnant wave axis and enhanced low level convergence with this system continues west into the Caribbean, devoid of convection."

http://www.freewebs.com/emdolphinwx/analyses.htm

[Aric Dunn]

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org For Official Information please refer to the NHC and NWS products.

I've been reading through the last several hours of post. I'm still going with my forecast from earlier today. I really don't see rapid intensification as shown by SHIPs. I expect possible slow development, if any, with a marked decrease in convection coverage as it heads west.

You really have to look at the SSTs ahead of the system. While they are high just off Africa, they do cool as you go west. Consequently I don't see this system rapidly intensifying. I don't see any NW turn at all. Just a west to west southwest course initially followed by a west to WNW course as the system remains at strong tropical wave with an attached low or a depression.

and SAL is another issue in this thing's path. It should help decrease the convection as well. If it goes poof by the time it hits those slightly lower SSTs it really would not surprise me although I am expecting at most a depression moving westbound for the next several days.

well according to this image from yesterday .. as long as it stays westerly ... it should stay just with in the 26c..