Area of Disturbed Weather Near the NE Florida/Georgia coast

[boca]

This is an ULL East of the Bahamas and is their a chance of it working down to the surface.It looks like it's drifting west towards Florida that's why it has my interest.

[northjaxpro]

I enjoyed the new NHC terminology in their Tropical Weather Dicussion earlier this morning, describing the Mid-Upper Level feature near 24.0N and 70.0W as a "cyclonic circulation center". Good way of describing the feature and it is an interesting one to me.

This feature is spinning in seemingly the only conducive area for tropical cyclone development in the North Atlantic basin for the 2014 Hurricane season to this point, off the SE U.S. coast. Now, although it is in the mid-upper levels, it will take quite sometime for this to burrow down to the surface, but it is not crazy to think that this may do this as it drifts west. Maybe nothing will come of this feature and I'm not anticipating any development immediately, but I think it is worth keeping a watch during the course of this week.

NHC excerpt from TWD 8 a.m.

AN ATLANTIC OCEAN TROUGH EXTENDS FROM 30N60W TO A 24N70W
CYCLONIC CIRCULATION CENTER...TO THE WINDWARD PASSAGE...INTO THE
WEST CENTRAL SECTION OF THE CARIBBEAN SEA. MIDDLE LEVEL TO UPPER
LEVEL CYCLONIC WIND FLOW THAT IS IN THE ATLANTIC OCEAN...MOVING
AROUND THE 24N70W CYCLONIC CENTER.

[HURRICANELONNY]

Should enhance showers during the week but no mention of a llc forming.

[northjaxpro]

The 12Z GFS did depict this system trying to develop some sort of weak surface reflection / trough entering into the Bahamas within the next 72 hours. The WFO in Miami did mention this in their morning discussion earlier today with moisture increasing across S. Florida later this week from this feature.



Also, this run of GFS shows potential "Dolly" about to make landfall on the Northern Mexico coast.

[gatorcane]

Certainly a little intriguing and here is a saved loop showing the area of interest:

[chaser1]

Though not very common, its not atypical at all for such cold core systems to develop into warm core systems in the mid latitudes. Even more common during El Nino years. It certainly is convecting, and why not given the very warm SST's. Certainly worth keeping an eye on.

Here's a question for any of you statistic (no, not sadistic LOL) minded out there. Any idea how many modern era named storms we've had and which turned out to be the strongest?

[cycloneye]

northjaxpro ,to let you know that I merged your thread with bocas's one as he posted about the same area two minutes before you did and to not have duplicated threads about the same topic I did the merge.

[northjaxpro]

OK. I have been on here very sporadically today, so I did not see Boca's thread earlier. No problem whatsoever. Thanks cycloneye for the merging of the threads.

Also, the 12Z GFS 120 hr run takes watev er remains of this feature into the SE Gulf of Mexico being steered by the ridge located to the northeast.

[northjaxpro]

Convection has increased a bit this morning with the mid-upper level Low which is now traversing through the Florida Straits. SSTs are extremely high in that area and although it takes a long time for these type of features to burrow down to the surface, this is something to still keep an eyeon this week. If the upper environment can become at least marginallly conducive for development, there is a slight chance a surface reflection could burrow down as this feature enters into the SE GOM.

Mods may need to edit the thread name now that this mid-upper Low is currently in the FL Straits.

[gatorcane]

Nice blowup of convection, let's see if the convection maintains throughout the day or slowly dies off as we head towards DMIN later.

[Steve]

I like to watch behind upper lows moving west or west-southwest in that area. You'll occasionally find development under increasingly better conditions in the wake. There really isn't much on the map behind it except the wave a few hundred milse to the SE just north of the coast of Suriname. Perhaps in a few days?

[AJC3]

I like to watch behind upper lows moving west or west-southwest in that area. You'll occasionally find development under increasingly better conditions in the wake. There really isn't much on the map behind it except the wave a few hundred milse to the SE just north of the coast of Suriname. Perhaps in a few days?

More often than not, this is what happens in the case of mid/upper level lows or troughs, including TUTT cells. Rather than the actual low, or vort center, "burrowing down to the surface", what you get is baroclinic initiation (BI) or enhancement (BE) - i.e jet forced ascent, usually through upper level divergence on the east side of these features, which enhances convection, and can (if given enough time) eventually result in lowering surface pressures and the development of a TC or hybrid cyclone.

Of particular note, Invest 93L in October of 2011 was a classic case of some models (notably the ECM) forecasting "drilling down" type development of a "BI" surface low in the GOMEX, directly beneath the upper level feature, while others (e.g. the GFS) showed the more classic low development in the divergent ascending area east of Florida. The GFS solution turned out to be much closer to reality, with a locally notorious hybrid cyclone forming over the NW Bahamas and moving onshore the Florida east coast just north of Cape Canaveral.

While the operational forecasts I made for Florida favored the ECM solution, a certain met on here (he can take credit if he so desires ) correctly called for the GFS solution to verify.

Of course, there have been cases of a cutoff cold core upper low actually drilling down to the surface. The name escapes me (it must have been 10-15 years ago), but there was a classic late season TC offshore the SE U.S. that formed in this manner after the parent upper low sat in place for several days.

[Nimbus]

Seems to be losing its upper level signature, of course that could mean it loses the lift from shear.

[Steve]

Awesome stuff AJC3. One of the (many) reasons it's great to have you guys on here is the "why" and "how" information. Plenty of us know where to maybe look for development, but most of our explanations are simplistic at best. The science behind the watching is so important in helping understand these processes. Gracias.

[beoumont]

130 mph Hurricane Diana in 1984 started as a cold low near the Bahamas. The preliminary NHC report is here: http://www.nhc.noaa.gov/archive/storm_wallets/atlantic/atl1984-prelim/diana/prelim01.gif

The 2nd paragraph details the genesis as a 200 mb cold low.

I marveled at the satellite loops, watching a counterclockwise upper level circulation transform itself over several days into a clockwise outflow mechanism.

[NDG]

I have been watching this feature for the last couple of days also, it seems that it is now more pronounced in the mid levels than it was at H20 a few days ago.

[AJC3]

I have been watching this feature for the last couple of days also, it seems that it is now more pronounced in the mid levels than it was at H20 a few days ago.

It's deforming (i.e. stretching/shearing out) pretty rapidly aloft. The RUC shows a pretty pronounced swath of H25 deformation extending from western Cuba NE through the eastern FL straits, Grand Bahama Island and a little farther NE. The trough at H50 doesn't appear to have changed all that much over the last day or so, but it never was a well-defined low center at that level, like it had been farther up in the atmosphere.

[northjaxpro]

The 500 mb vortcity analysis shows there has been a decent increase at that level regarding the elongated mid-upper Low axis, which extends SW to NE from south of Cuba through the NW Bahamas. The center of the Upper Low is just off the northern Cuba coast approximately near 23N 80W.

[AJC3]

The 500 mb vortcity analysis shows there has been a decent increase at that level regarding the elongated mid-upper Low axis, which extends SW to NE from south of Cuba through the NW Bahamas. The center of the Upper Low is just off the northern Cuba coast approximately near 23N 80W.

If you go back and look at the last 24 hours, there really hasn't been an appreciable increase in the magnitude of 500 MB vorticity. If anything, it has become a little more elongated.

[northjaxpro]

Well, AJC3, it is a matter of judgment in interpretation with regards to the vorticity. The vorticity is stretched out now. We can I think at least agree that the vorticity has maintained itself over this time, but no question it is an elongated axis right now. There is no debating that aspect for sure.