Two African waves that may develop
Hello everyone, it's Jeff Masters back with you again after a long stretch of vacation. Now that the peak part of hurricane season is upon us, I'll be with you every day for the next few months, in what promises to be an unusually active Atlantic hurricane season. We've got several threats to talk about today, most notably a strong African wave near 12.5°N 30.5°W, about 400 miles west-southwest of the Cape Verde Islands. This system, dubbed Invest 92L by NHC, is moving west to west-northwest at 10 - 15 mph, and has the potential to develop into a tropical depression or tropical storm before arriving near the northern Lesser Antilles Islands early next week. Recent visible satellite loops show that 92L is beginning to develop a surface circulation, and heavy thunderstorms are slowly building along the western edge of the center. However, a separate area of heavy thunderstorms lies 400 miles to the east, just south of the Cape Verde Islands, and this blob is interfering with consolidation of the center near the blob of heavy thunderstorms at 30.5°W. Water vapor satellite loops show that a large area of dry air from Africa lies just to the west of 92L, but the atmosphere in the immediate vicinity of 92L is moist, so dry air is currently not a problem for the storm. The SHIPS model is diagnosing low shear, 5 - 10 knots, over 92L, but the University of Wisconsin CIMSS analysis shows that moderate shear of 10 - 20 knots is affecting 92L. Sea surface temperatures are 26.5° - 27°C, which is very close to the 26.5°C threshold usually needed to support a tropical storm.
Figure 1. Noon satellite photo of Invest 92L.
Forecast for 92L
Low to moderate wind shear of 5 - 15 knots is predicted along 92L's path over the coming three days, which should allow the storm to steadily organize, assuming it can shut out any incursions of dry air that might intrude. The latest 00Z and 06Z model runs of the four best models for predicting tropical storm formation (GFS, ECMWF, NOGAPS, and UKMET) show little or no development of 92L, and NHC gave 92L just a 20% chance of developing into a tropical depression by Friday morning in their 8am outlook. Given the recent improvement in the satellite appearance of 92L, I would put these odds at 30%. A steady west to west-northwest motion for 92L is predicted by all of the models, which would put the storm in the vicinity of the northern Lesser Antilles Islands by Sunday. On Saturday and Sunday, 92L is expected to enter a region where an upper-level low pressure system will bring high wind shear of 20 knots to the storm, which should slow development. This upper-level low is also expected to turn 92L more to the northwest, so the storm may pass north of the Lesser Antilles. It is too early to know if 92L will recurve out to sea and potentially threaten Bermuda, or continue to the northwest towards the U.S. East Coast.
Figure 2. NASA MODIS image taken at 10:40am EDT 8/10/11 of the tropical wave emerging from the coast of Africa. The GFS model is predicting this system will develop into a tropical storm early next week. Image credit: NASA.
Tropical wave emerging from the coast of Africa
A strong tropical wave currently emerging from the coast of Africa near 8°N has a modest amount of spin and heavy thunderstorm activity associated with it, and has the potential to develop early next week once it moves past the Cape Verde Islands. The GFS model has been developing this system into a tropical storm in several of its recent runs. A westerly track towards the Lesser Antilles is expected by the GFS model.
Jeff Masters
Reader Comments
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relix smellix qlq hay pa... seein 40kt barbs on that cv wave reminds me of hugo
Yep, have visited Galveston in the moddle of July every year since 2003, and its amazing how much they've built back, though tourism has sadly plumeted and may not return to where it was for years...
talk to her in french, see what happens
Hey pulse...
A huge dip in the jet stream along the east coast of North America has shifted winds throughout a deep layer of the atmosphere. This pattern could last through the end of the month, according to some long-range computer forecast models. As you know if this dip in the jet stream, known as a trough of low pressure, persists through August, there’s a good chance that tropical storms and hurricanes attempting to reach the east coast of the United States will turn out to sea before becoming a serious threat.
well...at that time he was for sale...but...at this point....I'd consider just giving him away....
I love Rob and Crown Weather. I've been using their site for at least 10 years. I'm in agreement with him that 92L probably won't see any southern landfall even though it may become a hurricane mid-Atlantic. 93L is low enough that it has potential. Lucky for us most CV waves recurve or disapate.
yup, with ridging and lows u got to go thru the path of least resistance. we all know how the gom is (we've even got gomcasters) so...
i hate hangovers
TS BUSTED FORECAST ALIBI
Always fascinating to me how so many of the CV waves look very healthy, likes the ones out there now, in spite of dry air or SAL surrounding them but they moisten up their immediate environment and continue to develop, to a point. However, on these earlier ones, many get choked off if they do organize into a TD or TS because they then start to suck in that dry air outside their immediate environment. My point is that regardless of complete, or incomplete, development of these two down the line, they will make it much easier for those that follow in the coming weeks as they moisten up the middle passage which helps the others fight off dry air intrusion.
Yep, and some models are hinting at another potent wave to emerge off of Africa after these two...
Franklin~ 93L
Gert~ 92L
Harvey~ Possible homegrown system in coming days
Irene~Possible cape verde system; uh oh, everyone the I NAME.
I am guessing if 93L was supposed to go further westward and is now expected to recurve (even though it is too early and we can not fully trust the models), it's forward speed must be catching up to that of 92L which could mean future storms after 93L could hit the SE CONUS if and when the expected pattern change takes place.
someone chime in if I am wrong
92= another boring fish
93= probably the same.
Who miss the days when noodles used to show those kinda systems moving west for days with no sign of recurvature until it gets near the gulf???
Thanks but no thanks even for free I have a 17 year old also but a FEMALE UGGGGGHHHH. But shes not for sale or give away I have not tormented her near enough yet... lol
Some euro ensemble models i looked at yesterday evening due actually show a ridge building.
Now the season can begin to roll.
Unlike many of us you must not live in an area affected by storm surge. I'm here for an early heads up to when my house going to flood, not wishcasting a storm up someones azz.
MJOLNIR = MJO Likely Not (favorable) In Region
Never has had tourism, Galveston really doesnt have anything to offer.
MJO Real Time Forecasts.
Bi-polar. Has always been this way. The GFS will turn your hair white. Funny thing is... Sometimes it nails the eventual track on its first run, even though the 20 some odd runs after that are anywhere from Baja to Maine. LOL!
That would be great news for the islands as well as Florida and the rest of the East Coast. It's the home grown Carib storms that worry us on the Gulf Coast.
Haven't been there in over 20 years....but I thought it had a pretty vigorous nightlife...but, then again, maybe it was just me who had the vigorous nightlife...
Woohoo!
lol, no, it has no nightlife, must be you
2000: Isaac, Category 4; No US landfall
2001: Iris, Category 4; No US landfall(Retired)
2002: Isidore, Category 3; Landfall on US(Retired)
2003: Isabel, Category 5; Landfall On US(Retired)
2004: Ivan, Category 5; Landfall On US(Retired)
2005: Irene, Category 2; No US Landfall
2006: Isaac, Category 1; No US Landfall
2007: Ingrid, Tropical Storm; No US Landfall
2008: Ike, Category 4; Landfall On US(Retired)
2009: Ida, Category 2; Landfall On US, she was mean but not the worst
2010: Igor, Cateory 4; No US Landfall(Retired)
2011: Irene, COMING SOON...
yeah,it dosent see the trough to pull it north..I just want to know which model is better at predicting troughs and highs..these elements are going to be the key player in CV storms..I wonder if Dr. Masters could talk about that in one of his updates..right now the GFS is back and forth with its runs..
Do you see what's in the SW Carib in that run?
Hey SJ, How ya been mate!
Back in 2006 I took my family on vacation to Galveston. We were going on the Carnival Conquest, the huge Cruise ship that preKatrina docked in New Orleans.
On the way we drove down to Holly Beach first to see the Rita devestation. At the time not one structure had been rebuilt, not even a piling driven. A few hours later after leaving the destruction on the LA coast we drove along the TX coast. I told my family that one day all those nice houses with their toes sticking in the water would be gone some day. I never would have believed that it would have been only 2 years later with IKE.
So you don't see any home brew action from the stalled out cold front in the GOM next week ?
LOOOOONG ways out still. We still do not even have a closed circ for the models to run yet.
THE MODEL GUIDANCE GENERALLY AGREES ON TROUGHING HOLDING NEAR BOTH
COASTS...THOUGH THEY WEAKEN WITH TIME AS THE FLOW PATTERN BECOMES
LESS AMPLIFIED/MORE ZONAL. ISSUES BEGIN WITH THE WEST COAST
TROUGH...WHICH THEN TRANSLATE THROUGH SOUTHWEST CANADA AND THE
NORTHERN PLAINS. THE 00Z ECMWF BECOMES OUT OF PHASE WITH THE
OTHER DETERMINISTIC/ENSEMBLE MEAN GUIDANCE BY THE END OF THE
PERIOD ACROSS THIS REGION...SO IT COULD NOT BE USED AFTER TUESDAY
MORNING. THE 00Z CANADIAN HAS A LESSER VERSION OF THIS PROBLEM AS
WELL...AND ADVERTISES A FULL-BLOWN HURRICANE WEST OF BERMUDA LATE
IN THE PERIOD SOMEWHAT NORTHEAST OF THE COORDINATED POINTS FROM
THE 17Z COORDINATION CALL WITH NHC...WHICH IF PREFERRED WOULD HAVE
REQUIRED SUBSTANTIAL WEAKENING OF THE PRESSURES IN ITS VICINITY BY
AGREEMENT.
THE 00Z GFS FIT BEST WITH THE 00Z GEFS/12Z ECMWF ENSEMBLE MEAN
GUIDANCE...SO FOUND IT USABLE THROUGH THE PERIOD. THE PRESSURES
WERE DERIVED FROM A 00Z GFS/00Z ECMWF COMPROMISE INTO TUESDAY
MORNING BEFORE SWITCHING TO A 00Z GFS/12Z ECMWF ENSEMBLE MEAN
SOLUTION THEREAFTER. THIS LED TO SOME SLOWING TO THE SYSTEM
PROGRESSION ACROSS SOUTHERN CANADA/THE NORTHERN PLAINS FROM
CONTINUITY. OFFSHORE THE SOUTHEAST...USED THE POINTS COORDINATED
BETWEEN HPC/NHC AT 17Z YESTERDAY AND MERGED THE TROPICAL FEATURE
WITH THE FRONTAL WAVE IN ITS VICINITY BY NEXT THURSDAY MORNING.
hmmm -- pretty sure we close to an "x" rating! lol
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