atlantic hurricane season Atlantic hurricane season/invest thread

[be cause]

Looks like the latest ECM forecast has it deepening and spinning up the coast toward New Foundland and beyond ! Maybe off to stir up the Arctic ? 

[Cookie]

91L 

 

Recon was meant to go today ( Sunday) is now going tomorrow (Monday) instead

[knocker]

Yesterday's p.m.'s HWRF has would-be Arthur making landfall as Cat 1 hurricane the morning of July 4th near the NC/SC border pic.twitter.com/LV5lP4RUzz

[Gael_Force]

Yes, around Cape Hatteras seems to be convergence point from the latest tropical runs. Still a very mixed bag on intensity.

 

 

 

Source.  http://www.ral.ucar.edu/guidance/realtime/current/

[Cookie]

91L

 

Special Tropical Outlook 

 

PECIAL TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
430 PM EDT MON JUN 30 2014

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Special outlook issued to update discussion of the area of low
pressure east of Florida.

Updated: An Air Force Reserve unit reconnaissance aircraft is
investigating the area of low pressure centered about 110 miles east
of Melbourne, Florida. While the low is well defined, the
associated thunderstorm activity is just below the organizational
threshold required to initiate tropical cyclone advisories.
Environmental conditions continue to be favorable for development,
and only a slight increase in the organization and persistence of
the thunderstorm activity would result in the formation of a
tropical depression.

Data from the reconnaissance aircraft indicate that peak sustained
winds with the low are about 30-35 mph. The low is moving
southwestward at around 5 mph, but is expected to turn westward
tonight and northward by Wednesday when it will be near the east
coast of Florida. If this system becomes a tropical cyclone, a
tropical storm watch could be required for portions of the central
or northern Atlantic coast of Florida. A turn toward the northeast
near the southeastern U.S. coast is expected by Thursday.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 5 days...high...80 percent.

$$
Forecaster Franklin

Edited June 30, 2014 by cookie

[Somerset Squall]

Convection is steadily increasing, I can't imagine it'll be too long before 91L is upgraded to the season's first tropical depression.

[knocker]

GFS 00z forecasts fairly rapid extratropical transition of #Arthur late on 4th - trough interaction prior to Canada. pic.twitter.com/L5nvOqmLCq

Edited July 1, 2014 by knocker

[Cookie]

91L - Became Arthur 

[summer blizzard]

Shear just went below average for the first time since early May. Provided it sticks around then the Cape Verde season is a go.

[summer blizzard]

20% chance of development in 5 days. Not a bad environment ahead if it does form and a ling tracker forming pretty far south.

[summer blizzard]

Now at 40% in 48-120 hours.

[Gael_Force]

Now invest 93L.

 

AL, 93, 2014072806, , BEST, 0, 103N, 310W, 20, 1013, DB, 34, NEQ, 0, 0, 0, 0, 1015, 150, 60, 0, 0, L, 0, , 0, 0, INVEST, S,

This one, if it develops, should have fewer problems with dry air.

 

 

Source.

 

http://rammb.cira.colostate.edu/products/tc_realtime/storm.asp?storm_identifier=AL932014

[summer blizzard]

30% chance within 48 hours, 70% in 48-120 hours. Another system behind should also have a good chance of development going by some model runs.

With regards to 93l the track suggests that it will hit the Lesser Antilies but a persistent trough should recurve it before a US landfall.

With regards to strength the ships is good. Low shear, increasing heat content and a divergent upper flow. I'd say chances of hurricane strength are good.

[summer blizzard]

Good news is that that the 12z Euro for the first time backs genesis.

 

[Vorticity0123]

93L is definitely a good candidate for development in the next few days. The system currently consists of a broad area of fairly deep convection with no banding features yet present (as of 20:30 UTC). This can be seen in the Dvorak image of 93L below:

 

Dvorak satellite image of 93L (Courtesy: NOAA)

 

The system is currently in a rather moist environment. However, there is a large area of dry air (possibly SAL, Saharan air) to the north of the system in the vicinity of 16N (the system itself is located at around 10N, see Dvorak image above). This area might interfere with development in the later timeframes. Below is an analysis of the humidity profile near 93L.

 

Relative humidity profile around 93L. The colour shadings indicate the relative humidity near 93L. (Courtesy: NOAA)

 

Sources:

http://www.nhc.noaa.gov/satellite.php

http://www.nrlmry.navy.mil/coamps_docs/codta/2014/tc/93L/2014072806/2014072806.000_700RHcom_g2.gif

[summer blizzard]

Now a cherry at 70%, looking at the radar I suspect it will be declared TD3 overnight since its pretty close already.

[summer blizzard]

Clear circulation but struggling for deep convection due to dry air..

 

[summer blizzard]

Dry air is exposing the well defined circulation at low levels. Warmer waters are ahead but the further south it stays the more chance it gets shredded by Haiti due to less northward movement.

Needs to spruce up tonight or it may die completely.

[summer blizzard]

Recon will be in around 5pm our time. Convection is more organized and Ascat reports a closed low. I'm not entirely sure if the center is vertically stacked though, it may realign.

It may be enough to be declared tonight or we may still be waiting.

[Gael_Force]

Levi Cowan has a look ahead at conditions for the peak of the season.

 

[summer blizzard]

We now 94L. Currently a largely unorganised wave axis south of Cape Verde it does have a 40% chance of development within the 48-120 hour timeframe. 

 

Much like Bertha it will struggle with dry air but it's moving slower (should cope better in theory), should it reach the Lesser Antilles a TUTT will put it under some strain but if got past that then conditions are favourable. While a high likelyhood of being a FISH if it forms so far west (probably around 40W if it can get going) the ridge is much stronger north of the system this time so would increase the chance of a Florida/East Coast hit. Should it develop of course. If it fails to develop then it gets a shot in the Carribean once it passes the TUTT.

 

 

 

 

 

 

tropical wave accompanied by a broad low pressure system is
located a few hundred miles southeast of the Cape Verde Islands.
This disturbance continues to produce a large area of cloudiness and
showers, and some slow development of this system is possible over
the next several days while it moves westward at 10 to 15 mph.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...medium...40 percent.

[mezzacyclone]

Reckon 94L got their attention with the initial pouch formation/size and WV present as the SAL sure looks a factor to prevent dev in the coming days although Jeff Masters also got interested yesterday?

raised and lowered the 5day possibility % so a creeper and imagery watch SB?

[summer blizzard]

Reckon 94L got their attention with the initial pouch formation/size and WV present as the SAL sure looks a factor to prevent dev in the coming days although Jeff Masters also got interested yesterday?

raised and lowered the 5day possibility % so a creeper and imagery watch SB?

 

Aye. Slow burner if at all.

 

UKMO0z did develop it in the Caribbean Sea and Euro now picking it up.

[summer blizzard]

Looking at the GFS12z GFS suggests that subsidence and dry air prevent this from developing.

 

At day 7 however (high res) it does pick up a system near Cape Verde which develops through the run.

 

 

[Gray-Wolf]

Well we are entering into 'peak season' so I'd hope it can limp through the dry air and then have a shot at developing over the other side of the basin?