Model Runs & Discussions of GOM-Bahamas

[MiamiensisWx]

There is strong upper-level shear to the NW, but the sfc trough and Bahamian convection is acquiring the "slow fuse" stationary system appearance. The "popcorn" convection can indicate good instability; J/KG values and CAPE; and a pre-existing instigator that enables thunderstorm formation. I think we could (key word is "could") see something if shear relaxes over the area. The following loop offers an interesting view. Remember Humberto and other systems that rapidly formed when conditions became more favorable. We should slowly observe a shift of the W Caribbean anticyclone closer to the Bahamas, which could aid better upper-level conditions. Additionally, ronjon mentioned mid-level energy, which could spark more convection over the area. Shear is much lower to the SW and SE of the Bahamian system, so conditions should gradually improve over the Bahamas, too. Model guidance strongly suggests this possibility is a plausible scenario: a building 500 mbar ridge and anticyclone would favor tropical cyclogenesis.

http://www.ssd.noaa.gov/goes/east/watl/loop-ir2.html

http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/winds/wg8shr.html

By the way, it is becoming more clear that the Gulf system (depicted by the models) originates in the Bahamas from this system, as mentioned by ronjon's post.

[KFDM Meteorologist]

From the NWS Lake Charles, LA


.LONG TERM...
FOR FRIDAY THROUGH MONDAY...A SURFACE LOW AND INVERTED SURFACE
TROUGH ARE PROGGED TO MOVE ACROSS THE CENTRAL GULF OF MEXICO
FRIDAY AND SATURDAY. THIS SYSTEM COULD REACH THE MID TO UPPER
TEXAS COAST SUNDAY. IT IS PROGGED TO WEAKEN OVER TEXAS MONDAY.

[Steve]

>>Yesterday it was New Orleans. No reason to start pinpointing Houston or Golden Triangle with nothing "formed" yet. Long week ahead.

That's not what I said. I said that model was trending more northerly toward the end of its run toward Galveston/Golden Triangle.

That's not my call, it's the UKMET's from the run cycloneye posted. If you wanted my call, you should have asked me. I would have told you that I think Texas is the most likely scenario for the system not-yet-formed-and-possibly-never-will-but-might or something like that.

Steve

[Extremeweatherguy]

Yesterday it was New Orleans. No reason to start pinpointing Houston or Golden Triangle with nothing "formed" yet. Long week ahead.

Well that depends on what model you are referring too. Some did show N.O. at times, but I believe the ECMWF was mainly pointed at TX yesterday, as well as a few other models.

[cpdaman]

well something is forming in the central bahamas and it is the feature we should be watching because it has GOM written on it

25 76 ish

this may be our "player" this board may be hopping by mid week

[Extremeweatherguy]

>>Can't tell if this is now a semi-offical JB prediction or not, but Texas as at least a tropical storm, just now, on the PPV JB page.

"at least a tropical storm" ain't the same as "probably a major", but we'll see with the evolution of time.

Steve

Here is more precisely what he said..

will impact the Texas coast this weekend or early next week with tropical-storm, and perhaps even beyond, conditions.

Seems like the timeframe would be this weekend or early next week as a tropical storm or greater in intensity....according to JB.

[HURRICANELONNY]

Everybody is talking about lows developing everywhere. From Texas to S.Fl. The models are are over the place on different runs. I think the consesus is the lowering of pressures so the models bring up lows in different locations. Will it happen exactly or even close where they show. Doubt it. But probably somewhere in the South. Something will develop in time.

[skysummit]

Everybody is talking about lows developing everywhere. From Texas to S.Fl. The models are are over the place on different runs. I think the consesus is the lowering of pressures so the models bring up lows in different locations. Will it happen exactly or even close where they show. Doubt it. But probably somewhere in the South. Something will develop in time.

What??? Have you even been keeping up? The models are pretty much all in agreement of where this possible system will come from. They're not "all over the place" like you're saying. Plus, no one is talking about lows developing "everywhere". The whole discussion is what's going on east of Florida. Try to keep up a little better.

[Derek Ortt]

Humberto also had a large trough to enhance it. This one does not appear to have the same baroclinic dynamics to allow for another Humberto

[Stratosphere747]

Quite a bit of wiggle room with sentiments like that...

Just a few minor differences between a TS and "beyond."

[LaBreeze]

That which we know - something will develop somewhere.

[Pearl River]

EWG wrote:

Wx_Warrior wrote:
Yesterday it was New Orleans. No reason to start pinpointing Houston or Golden Triangle with nothing "formed" yet. Long week ahead.
Well that depends on what model you are referring too. Some did show N.O. at times, but I believe the ECMWF was mainly pointed at TX yesterday, as well as a few other models.

The 12z Euro had it pointing at New Orleans yesterday. It's been jumping around too.

[ronjon]

Well, on the models we have a camp of models that develop something in the bahamas and another camp that develop something in the SE GOM. I personally believe the Bahamas is where cyclogenesis will occur do to the favorable synoptic set up - strong ridging to the north, top of tropical wave that has fractured off, and mid-level energy dropping south off the NE FL coast. The other models in the SE GOM seem to focus development on the ULL itself transforming it to a warm core tropical system once it is in the GOM. While possible, I think the greater odds favor a Bahamas low pressure system migrating in tandem westward with the ULL.

[MiamiensisWx]

Recent obs from Nassau, Bahamas indicate variable winds and ~1015 mbar. Earlier obs indicated ENE winds, but they diminished when the sfc trough moved over the area.

http://weather.noaa.gov/weather/current/MYNN.html

Humberto also had a large trough to enhance it. This one does not appear to have the same baroclinic dynamics to allow for another Humberto

You're correct. The synoptic setup is much different than Humberto. I was speaking in broad terms that "anything is possible". I don't see rapid development, but I think the ingredients suggest development is becoming more plausible in this area. The main point indicates there is a developing model consensus for possible tropical cyclogenesis in the Gulf of Mexico or Bahamas (off SE Florida). The time frame suggests the models are picking up development from this area in the Bahamas. The Euro, GFS, and other models move the initial piece of energy from the Bahamas W into south FL and the GOM, so they are initializing this system. The Gulf system likely originates from the Bahamas system.

[skysummit]

With that being said, the northwest Caribbean and extreme southern gulf are getting quite favorable right now with high pressure building aloft. Also, shear has dropped near the Bahamas to near 10kts and looks to still be improving.

[MiamiensisWx]

New data has arrived, and it supports my satellite observations. Shear has decreased over the Bahamas, and it should graduaslly diminish over the next 24 hours. This trend is taking place when the models suggested a better upper-air environment would slowly develop; the data suggests the models weren't reflecting a blip. It was a consensus that indicated a trend. Additionally, conditions are becoming more ripe across portions of the Gulf of Mexico. If a sfc low forms, it will become problematic to search for relocations, especially when conditions are improving and convective parameters are favorable.

Current shear:

http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/winds/wg8sht.html

Three hours ago:

http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/winds/archive/wg8sht-1.html

Shortwave:

http://www.ssd.noaa.gov/goes/east/tatl/loop-ir2.html

RAMSDIS visibles

RAMSDIS WV

[gatorcane]

Ex-ingrid is on her way to the Bahamas it appears. She may also play into this concoction you are suggestion

[Ed Mahmoud]

I paraphrased JB, as I am not sure if cut-n-paste of his PPV column is allowed by AccuWx. I paraphrased pretty well, I think, 'at least a tropical storm' is about the same as what JB said.

[MiamiensisWx]

One word of caution: don't focus on the cloud movement. The convection may appear to be drifting N, but we don't have a defined sfc low. Additionally, more convection will probably form further SE near the Turks and Caicos. There will be many "wobble watches" in the coming days, so I thought this post would be a good reminder to focus on the synoptic setup. Current WV at the mid to upper levels (click here) shows an upper low moving W into mainland Mexico. This movement indicates a ridge. The main "energy" (not convection) is focused near the Turks and Caicos. The northernmost convection may weaken, but this behavior reflects the early "pulsing" stages. Convection will likely blossom further S - watch the next 24-36 hours. Additionally, the building mid-level ridge argues for a WNW-W track toward FL and the Gulf of Mexico. Look at the movement of an UL feature (remnants of Humberto) in the NE GOM. It is moving S.

[skysummit]

The 18z NAM has a similar scenario to the 12z Canadian......here it is a 84 hours. I drew the track in.