92L very disorganized, but a long-range threat to develop
Invest 92L, which yesterday became severely disrupted by wind shear and dry air, is generating a large area of rain showers over the northern Lesser Antilles Islands today. Infrared satellite loops show that the tops of the thunderstorms associated with 92L have warmed in recent hours, and these thunderstorms are weak and disorganized. Water vapor satellite loops show that there is a large amount of dry air in the storm's environment, and this dry air is getting sucked into 92L's thunderstorms, where the dry air is sinking to the surface and creating surface "arc clouds"--arc-shaped clouds that spread out away from 92L's thunderstorms. With wind shear at 20 - 30 knots today, no signs of a surface circulation, and plenty of dry air around, 92L is not a threat to develop into a tropical depression today or Saturday. The National Hurricane Center is giving 92L a low (20% chance) of developing into a tropical depression by Sunday morning. I put the chances at 1%. You can track the progress of 92L today by looking at our wundermap for the region, with weather stations turned on. Antigua recorded sustaiined winds of 20 mph this morning from 92L.
A slight chance 92L could develop next week
Today and Saturday, 92L will encounter 20 - 40 knots of wind shear as it plows though a region of strong upper-level winds associated with the subtropical jet stream. The disturbance will also encounter the mountainous terrain of Hispaniola. These factors should significantly disrupt the disturbance. If there's anything left of 92L by Sunday, when it will be over eastern Cuba, the storm may have the opportunity to develop. At that time, 92L will have passed through the core of the subtropical jet stream and entered a region of lower shear (15 - 20 knots.) For the latest round of 00Z and 06Z model runs, the HWRF is the only reliable model calling for 92L to develop; that model predicts that 92L will organize into a tropical depression on Wednesday over the Lower Florida Keys, and head into the Gulf of Mexico. The obstacles that 92L must overcome to do this are great, and I give 92L just a 10% chance of eventually developing into a tropical depression by Wednesday next week.
Figure 1. Morning satellite image of Invest 92L. Dry air is getting sucked into 92L's thunderstorms, where the more dense dry air creates downdrafts. When these downdrafts hit the surface, the air spreads out creating surface "arc clouds"--arc-shaped clouds that spread out away from 92L's thunderstorms. This puts stable air into the storm's low level environment and blocks inflow of moist air into the core of the storm, weakening it. These arc clouds are a telltale sign that dry air is significantly disrupting the disturbance.
Elsewhere in the tropics
The NOGAPS model is calling for a tropical disturbance to form off the coast of Nicaragua on Monday and push ashore over that country on Tuesday, bringing heavy rains.
Wind and ocean current forecast for the BP oil disaster
Light and variable winds less than 10 knots will blow in the northern Gulf of Mexico for the next five days, according to the latest marine forecast from NOAA. The winds will tend to have a westerly component through Saturday, which will maintain a threat of oil hitting beaches as far east as Panama City, Florida, according to the latest trajectory forecasts from NOAA and the State of Louisiana. Ocean current forecasts for early next week show a weakening of the eastward-flowing currents along the Florida Panhandle, which would limit the eastward movement of oil so that it would not move past Panama City. The long range 8 - 16 day forecast from the GFS model indicates a typical summertime light wind regime, with winds mostly blowing out of the south or southeast. This wind regime will likely keep oil close to the coastal areas that have already seen oil impacts over the past two weeks.
Resources for the BP oil disaster
My post, What a hurricane would do the Deepwater Horizon oil spill
My post on the Southwest Florida "Forbidden Zone" where surface oil will rarely go
My post on what oil might do to a hurricane
NOAA's new interactive mapping tool allows one to overlay wind and ocean current forecasts, oil locations, etc.
Gulf Oil Blog from the UGA Department of Marine Sciences
Oil Spill Academic Task Force
University of South Florida Ocean Circulation Group oil spill forecasts
ROFFS Deepwater Horizon page
Synthetic Aperture Radar (SAR) imagery from the University of Miami
I'll have an update on Saturday.
Jeff Masters
Reader Comments
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I check weekly for updates and it says there are none.
I think it's the multiple browsers I have running for work that makes it crash.
mesoscale—Pertaining to atmospheric phenomena having horizontal scales ranging from a few to several hundred kilometers, including thunderstorms, squall lines, fronts, precipitation bands in tropical and extratropical cyclones, and topographically generated weather systems such as mountain waves and sea and land breezes. From a dynamical perspective, this term pertains to processes with timescales ranging from the inverse of the Brunt–Väisälä frequency to a pendulum day, encompassing deep moist convection and the full spectrum of inertio-gravity waves but stopping short of synoptic-scale phenomena, which have Rossby numbers less than 1.
Outflow Boundries... provide lift in the lower levels for other storms to pop up along them, chain reaction effect.
I know I am
An outflow boundary, also known as a gust front, is a storm-scale or mesoscale boundary separating thunderstorm-cooled air (outflow) from the surrounding air; similar in effect to a cold front, with passage marked by a wind shift and usually a drop in temperature and a related pressure jump.
Same thing but Outflow Boundary is the more technical term for it.
then backup your bookmarks and whatever, download the newest installer from the firefox website and install it. I wouldn't suggest using firefox anymore anyway, as chrome is the superior browser.
Strange I'm solid as a rock. On a Mac.
Just a you drop a a droplet of water into a puddle of water (Aka. The collapsing of a thunderstorm or a downdraft) there is a ripple created, that lifts up like a wave. This wave can raise air when it interacts with the wave and provides the opportunity for other updrafts to form along the wave and create new thunderstorms.
great that's me :)
Link
Let me know your thoughts.
I am working on the updates for the google earth images that show where the bloggers are located. Anyone who would like to be included, please send me WU mail with your zip code or post a comment on my blog.
It does not work for you to place it here - I don't get a chance to read everything throughout the day.
Zoo
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT FRI JUN 18 2010
FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...
A TROPICAL WAVE APPROACHING THE VIRGIN ISLANDS IS PRODUCING AN AREA
OF DISORGANIZED SHOWERS AND THUNDERSTORMS OVER THE LEEWARD ISLANDS.
ALTHOUGH THE SHOWER AND THUNDERSTORM ACTIVITY HAS DIMINISHED
SOMEWHAT THIS AFTERNOON...LOCALLY HEAVY RAINS AND GUSTY WINDS ARE
STILL POSSIBLE DURING THE NEXT DAY OR TWO OVER PORTIONS OF THE
LESSER ANTILLES INCLUDING...THE VIRGIN ISLANDS...AND PUERTO RICO.
UPPER-LEVEL WINDS ARE EXPECTED TO REMAIN UNFAVORABLE FOR
DEVELOPMENT...AND THERE IS A LOW CHANCE...10 PERCENT...OF THIS
SYSTEM BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.
ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.
$$
FORECASTER ROBERTS/BEVEN
Just another florida summer like afternoon. You get used to it after a while.
LOL, went a little overboard with the "and/or".
Afternoon -- we just had a mini tropical storm fly through - Homestead area.
EHI = .2 (EHI is a Tornado Index, .2 is very low)
STM = 78%uFFFD/3kts (Storm Relative Movement, at what direction and how fast storms will move)
CAP = 1.8 (How strong the CAP is, 1.8 is weak/moderate)
LCL = 997mb (How low clouds can go, 997 mb is very low)
PW = 1.7 (Precipitable Water, how much water is stored in a square meter throughout the entire atmosphere column, in other words volume)
LI = -6.8 (Lifted Index, -6 to -8 is very good for lift, thus starting of updrafts/thunderstorms)
looking at the latest GFS forecast for the MJO, if we dont get something in the next 7 days, we may not see any development at all until the 3rd week of July
by then those wanting something to track would be out of their minds and the down-casters would be out in full force claiming they were right and that everyone was stupid for over-hyping the season
If that happens, we could see a train of hurricane's, TS's, TD's all lined up.
how can you tell me that is false when 95% of the people on this site (me included) felt we would have Alex by now?
Well, I think that may be true in the primary June-July breeding grounds of the western Caribbean, GOM, and Bahamas, but not so farther east.
As incredible as this is, the next 4 weeks may see the eastern and central tropical Atlantic being more favorable and more likely for tropical cyclone formation than the Western Caribbean and Gulf of Mexico, which is absolutely unheard of for this time of the year.
A see the downward motion coming up.
There would be some beleaguered WU bloggers if it took that long. I'm not sure some could handle it.
0-0-0.
July-2
August-6
September-6
October-3
November-1
we are in an upward pulse from now and for the next 7-10 days, but shear is not favorable and by the time it will be, downward motion takes over
june-0
july-0
august-2
sept-2
oct-1
nov-1
EP 94 2010061818 BEST 0 131N 955W 25 1009 DB
pretell which system should have been Alex?
90L? No
92L? Sorry but even if it should have been a TD, it has never been a TS
Now if that is the case, then yes, the season will kick off soon
ECMWF has been persistent with a storm in the Carribean late next week.
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