Models Develop a Disturbance Near Florida (Is invest 90L)

[Tampa Bay Hurricane]

Here's what I think may happen...a low may form with combined
energy from the trough and the spin in the caribbean...it may
move NE first, but a building ridge may push it back into SE FL
or the straits...

Caribbean Moisture + trough = A deluge likely for FL...mainly central
and south...but most of the peninsula if it can get into the Gulf.

This low can become a tropical storm ONLY if the shear over the SE
Gulf decreases enough...with a trough the shear could be
very high...that shear is what normally precludes development
this early in the season, but with an El Nino possible later
this year...active early development is favored (we had 4 storms
by July of 1997), especially with the subtropical jet
over the gulf that occurs during el ninos and the troughs
el ninos bring down. I know it is not an El Nino yet,
but that is just a correlation that might be relevant.

[HURAKAN]

[Tampa Bay Hurricane]

All 3 models would bring significant rain to south FL. They show
very slow movement of the low, allowing for high rain totals.

Has accuweather said anything about tropical development? Usually they
are the first weather group to jump onto cyclogenesis after the NWS...


CHECK out the spin over East Cuba: It's got some convection.
Looks like some kind of low.
http://www.ssd.noaa.gov/goes/east/gmex/loop-rb.html

[HURAKAN]

A storm is likely to mature off the Southeast coast early next week. Its movement will be quite slow due to blocking high pressure to the north. The result could be a substantial amount of wind and rain to the entire coastline from Cape Hatteras, N.C., to Jacksonville, Fla. With the type of pressure gradient showing up on the computer models next Tuesday and Wednesday, coastal winds could easily reach 50 mph.

This disturbance could also produce quite a bit of rain in central and South Florida beginning on Sunday, coming primarily from pounding thunderstorms.

Story by AccuWeather.com Expert Senior Meteorologist John Kocet.


http://www.accuweather.com/news-story.a ... &article=5

[Bailey1777]

It looks like models are starting to trend towards this low bending back west deeper into the GOM versus an eastward journey.

[Tampa Bay Hurricane]

Jeff Master's says a sub-tropical system could form:
http://www.wunderground.com/blog/JeffMa ... rynum=1219

The 2009 Atlantic hurricane season may get off to an early start. For the past two days, most of our reliable hurricane forecast models have been predicting the possibility of a subtropical depression forming near Florida or Western Cuba Monday - Thursday next week. An area of disturbed weather associated with a mid- to upper-level trough of low pressure near eastern Cuba and the southeastern Bahama Islands is predicted to slide west-northwest over the next few days. Wind shear over this low, current a prohibitively high 40 knots, is expected to relax to just 10 knots by Monday in the region surrounding Florida. This may allow a disturbance with a surface warm core to develop, according to phase space analyses from Florida State. However, since the upper atmosphere will still be cold, any development of this system will likely be subtropical in nature. If a subtropical storm does form, it may be fairly dry, like Subtropical Storm Andrea of May 2007. This storm ended up fanning fires in Florida, instead of putting them out. Water vapor loops show plenty of dry, continental air in the region, and it will take many days for the atmosphere to moisten enough to support formation of a subtropical depression.


Figure 1. Water vapor image showing moisture from a weak mid- to upper-level low of low pressure over the southeastern Bahama Islands, surrounded by a large area of dry air, and sandwiched between the polar and subtropical jet stream. Image credit: NOAA/SSD.

The GFS and NOGAPS models predict a subtropical depression could form by Tuesday, while the ECMWF shows development later in the week. The latest UKMET model forecast puts development Wednesday or Thursday near Haiti. The area of predicted development is sandwiched in a relatively narrow band of low wind shear between two branches of the jet stream. This is not a typical set-up for formation of a May tropical cyclone. With so much shear and dry air around, I put the probability of a subtropical depression forming next week at about 10%. Any developing system will also have to contend with the arrival Tuesday of a strong upper-level low pressure system that is expected to drop down over the northern Gulf of Mexico. The eventual track of any depression that forms is highly uncertain, and the models support tracks up the U.S. East Coast towards South Carolina, or up the west coast of Florida in the Gulf of Mexico.

Season's first tropical wave arrives
The season's first tropical wave rolled off the coast of Africa yesterday, and is now located near 10N 20W, a few hundred miles off the coast of Africa, according to total precipitable water loops. Mid-May is a fairly typical time for these waves to begin moving across the Atlantic, though they usually don't start developing into tropical depressions until August. Last year was an exception, when Hurricane Bertha formed from a July tropical wave. Wunderground blogger Weather456 has been tracking the date of the first African wave each year since 2004, and these dates have ranged from May 2 to May 21. With Sea Surface Temperatures near average this year in the tropical Atlantic, an early season major hurricane in the eastern Atlantic like Bertha is unlikely.

[artist]

ok, so he is saying it may not bring any rain??

[Tampa Bay Hurricane]

ok, so he is saying it may not bring any rain??

Theoretically if it forms off the NE coast of Florida and shoots out to sea-
that would bring in dry air and kill off any rain.
But that is unlikely IMO, for several reasons:

1. the trough and associated low
are already pretty far south over
East Cuba per satellite imagery.

2. Most major global models- the 3 above, favor
a building ridge following the front that arrives by Monday
to push the low back into the GOM, putting Florida
on the wettest side of the low

3. With shear expected to drop, the low
pressure area may be able to concentrate
a heavy band of rain over the Gulf and Florida
without the moisture and the low for that matter
getting it's moisture blown out into the Atlantic
away from FL.

4. However, given dry air surrounding only a small area of moisture-
the dryness should prevent tropical intensification, so I think
we may have a subtropical depresssion or subtropical
storm to contend with at the most (especially
considering Jeff Master's explanation for such
a scenario)- but it should bring a lot of rain
(based on accuweather's scenario).


One thing is certain: Things look to get very interesting into
next week considering there is already a low spinning
along a trough over Eastern Cuba:
http://www.ssd.noaa.gov/goes/east/gmex/loop-rb.html

[gatorcane]

The 12Z ECMWF just out, more bullish on tropical development than any prior run so far, just east of Florida and out more around 144-168 hours:

Looks like a tropical storm forms just east of FL and gets very close to the coast, meandering around for days.

http://www.ecmwf.int/products/forecasts ... 9051412!!/

It should be noted that the UKMET 12Z is not as bullish on development.

[Tampa Bay Hurricane]

The 12Z ECMWF just out, more bullish on tropical development than any prior run so far, east of Florida and out more around 168 hours:

http://www.ecmwf.int/products/forecasts ... 9051412!!/

Looks to be similar to Andrea 2007 on that run; but if the other models verify (getting into
SE Gulf)...it may be more similar to Barry 2007...of course too early to tell but
those are some guesses that come to mind.

EDIT: ECMWF not too much like Andrea looks further south

[gatorcane]

The 12Z ECMWF just out, more bullish on tropical development than any prior run so far, east of Florida and out more around 168 hours:

http://www.ecmwf.int/products/forecasts ... 9051412!!/

Looks to be similar to Andrea 2007 on that run; but if the other models verify (getting into
SE Gulf)...it may be more similar to Barry 2007...of course too early to tell but
those are some guesses that come to mind.

EDIT: ECMWF not too much like Andrea looks further south

The ECMWF 12Z run is a bit odd if you ask me. It develops the low much farther north and east than the other models -- and keeps it hanging around the Bahamas and near the FL East Coast for several days, meandering around. Not only that but it definitely develops this low now, and into a tropical storm it looks like. That is a huge jump from previous runs which developed the low into a subtropical low at best.

The run may be suspect, we'll have to wait for the 00Z run later tonight.

[cycloneye]

Loop of possible suspect area next week.

[gatorcane]

There is a very distinct cyclonic twist that you can see there near the Northeastern Coast of Cuba and it seems to becoming more distinct with time.

[RL3AO]

Something similar to Andrea 2007?

[Vortex]

12Z Nogaps has losed low over southern florida and deposits very significant rainfall over the central/southern part of the state.


https://www.fnmoc.navy.mil/wxmap_cgi/cg ... rp&tau=132

[Tampa Bay Hurricane]

The low over Cuba is moving West and maybe WNW pretty
quickly...it could be near the FL straits by tomorrow

[Stormcenter]

And it (model watching) begins.

[Bailey1777]

I know radar is a limited tool but does anybody have a shot from around where this spin seems to be occuring?

[JonathanBelles]

I know radar is a limited tool but does anybody have a shot from around where this spin seems to be occuring?

Half of the radars in Cuba are down, but here is what is up:

http://www.insmet.cu/asp/genesis.asp?TB0=PLANTILLAS&TB1=RADAR&TB2=../Radar/NacComp200Km.gif

[Vortex]

18z NAM develops and moves low over south florida in H+90.

http://www.nco.ncep.noaa.gov/pmb/nwprod ... n_090l.gif