Invest 90L in the Tropical Atlantic
Hi everybody, Dr. Rob Carver filling in for Dr. Masters while he's on vacation.
NHC has designated an area of thunderstorms in the tropical Atlantic as Invest 90L (8.5 N, 30.0 W). Microwave remote sensing suggests there are some decent storms in 90L, peak rain rates were around 1-2 inches/hours. According to CIMMS wind-shear analyses 90L is under 10-15 knots of shear with positive divergence aloft. The former isn't quite favorable for further development as it will ventilate the system, but the latter is favorable because it will aid in removing outflow from the storms. There's also a broad area of weak shear to the west and northwest of 90L's current position. Looking at the 500 mb height patterns, the steering currents for 90L are to the WNW, which will move it into the area of weaker shear and get it further away from the equator. This is important because if 90L stays south, it will have trouble developing a circulation. It will have a better chance of becoming a tropical cyclone once it goes north of 10N. The Saharan Air Layer is lurking just to the north of 90L. A WNW track would keep 90L out of the SAL, which is good for development.
Fig. 1 IR Satellite Composite of 90L taken at 540 PM EDT.
Fig. 2 Saharan Air Layer analysis courtesy of CIMMS.
Model Forecasts and Climatology
The 12Z Canadian model moves 90L to the WNW and develops tropical-storm force winds at the surface. The 12Z and 18Z GFS runs are less aggressive in intensifying 90L and adjusts the track so that 90L is moving to the WNW. Based on the run-to-run consistency, previous model verification (i.e. the Canadian model's tendency to overdo intensification), general synoptic pattern, I favor the GFS solution for now. Looking at climatology based on research done by Dr. Bob Hart at Florida State University, none of the tropical cyclones that passed within 1 degree of 90L's current position has ever made landfall. We'll have to keep an eye on this storm, but I don't think it's likely to be a major threat to the Caribbean or US.
Update
Dr. Masters says he'll update this blog entry with a discussion of the Moscow heatwaves later tonight.
Reader Comments
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ABNT20 KNHC 292351
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT THU JUL 29 2010
FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...
SHOWERS AND A FEW THUNDERSTORMS ASSOCIATED WITH A TROPICAL WAVE ARE
MOVING ACROSS THE WINDWARD ISLANDS. THERE ARE NO SIGNS OF
ORGANIZATION AT THIS TIME...AND ANY DEVELOPMENT OF THIS SYSTEM
IS EXPECTED TO BE SLOW TO OCCUR AS IT MOVES GENERALLY WESTWARD AT
10 TO 15 MPH. LOCALLY HEAVY RAINS AND STRONG GUSTY WINDS COULD
AFFECT PORTIONS OF THE LESSER ANTILLES OVER THE NEXT DAY OR SO.
THERE IS A LOW CHANCE...10 PERCENT...OF THIS SYSTEM BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS.
AN AREA OF DISTURBED WEATHER IS LOCATED OVER THE EASTERN ATLANTIC
OCEAN ABOUT 650 MILES SOUTHWEST OF THE CAPE VERDE ISLANDS. THIS
SYSTEM SHOWS SOME SIGNS OF ORGANIZATION...AND SLOW DEVELOPMENT OF
THIS DISTURBANCE IS POSSIBLE DURING THE NEXT COUPLE OF DAYS AS IT
MOVES SLOWLY TOWARD THE WEST OR WEST-NORTHWEST. THERE IS A LOW
CHANCE...20 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.
$$
FORECASTER BEVEN
ABNT20 KNHC 292351
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT THU JUL 29 2010
FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...
SHOWERS AND A FEW THUNDERSTORMS ASSOCIATED WITH A TROPICAL WAVE ARE
MOVING ACROSS THE WINDWARD ISLANDS. THERE ARE NO SIGNS OF
ORGANIZATION AT THIS TIME...AND ANY DEVELOPMENT OF THIS SYSTEM
IS EXPECTED TO BE SLOW TO OCCUR AS IT MOVES GENERALLY WESTWARD AT
10 TO 15 MPH. LOCALLY HEAVY RAINS AND STRONG GUSTY WINDS COULD
AFFECT PORTIONS OF THE LESSER ANTILLES OVER THE NEXT DAY OR SO.
THERE IS A LOW CHANCE...10 PERCENT...OF THIS SYSTEM BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS.
AN AREA OF DISTURBED WEATHER IS LOCATED OVER THE EASTERN ATLANTIC
OCEAN ABOUT 650 MILES SOUTHWEST OF THE CAPE VERDE ISLANDS. THIS
SYSTEM SHOWS SOME SIGNS OF ORGANIZATION...AND SLOW DEVELOPMENT OF
THIS DISTURBANCE IS POSSIBLE DURING THE NEXT COUPLE OF DAYS AS IT
MOVES SLOWLY TOWARD THE WEST OR WEST-NORTHWEST. THERE IS A LOW
CHANCE...20 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE
DURING THE NEXT 48 HOURS.
ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.
$$
FORECASTER BEVEN
Eh, how many people are dying from heat in Moscow? Hundreds are dying in Peru from cold, guess that isn't worth mentioning, ever. Oh well.
yup it was
OCEAN ABOUT 650 MILES SOUTHWEST OF THE CAPE VERDE ISLANDS. THIS
SYSTEM SHOWS SOME SIGNS OF ORGANIZATION
NOOOOOOO!!!
SRACASM FLAG: ON
Hi Levi, what do think of these two new circles? Should they work there way to the Carribean or more northward?
LOL. I had it copied and pasted because I had not seen it yet. However, my instinct told me to refresh the page one more time. My instinct was correct. Three in a row!
Hard choice I'd go with the HWRF but it depends on the situation itself.
I might just avoid the blog for the same reason. Will probably be checking other non-troll/spam/freakish blogs on here for info.
My thoughts on 90L now:
Sorry! I meant Dr. Carver. My bad.
Someone posted an article earlier stating over 2,000. So yeah.
*****************************
Update
Dr. Masters says he'll update this blog entry with a discussion of the Moscow heatwaves later tonight.
*****************************
Uhhhh oooohhhhhhhh.... Can we just keep commenting on the blog?? lol
Where are you guys getting that? 20% of 109 is 21.8, or around 22. 109-22 is 87. 15% of 109 is around 16. 109-16 is 93, so 87-93 knots, so more or less 90 knots rather than 80 knots. I think?
10 kts is a big difference to me XD
We can still post on the other blog and try and make it to 10000 reallly slowly lol.
Go back and start talking about GW... You will be there in no time....
LMAO
I also agree with this. Also, I don't agree with anything somebody from FSU says :P
LOL
I assume there are people dieing there as well.
The 1st circle east of the Antilles is going straight through the southern Caribbean and will have to be watched for mischief farther west. Invest 90L will likely approach the northern Antilles but its exact track remains unclear, and at this time we can't really know whether it will spend any time in the Caribbean or not.
wow that is very very good conditions for 90L
from RAMMB
from SSD
SHEAR (KT) 5 9 8 8 11 9 12 10 7 8 5 10 7
Official recon flight-level wind reductions as stated at this year's NHC hurricane conference are as follows:
Recon Flight Wind reduction
1000 mb flight level = 80%
925 mb flight level = 75% (this one is closest to 900mb, so I used this one)
850 mb flight level = 80%
700 mb flight level = 90%
(in the voice of that guy that does the Outback steak house commercials)
"DRAMA CASTER"
LOL
SHIPS is junk. :)
Can we not and pretend we did?
PLEASE?!?!?! ;)
GFDL has 90L moving northwest immediately. It's current movement is WSW with steering indicating a WNW movement soon. The model run is not valid, imo. Both the HWRF and GFDL are never good on their initial runs.
marginal to favorable development throughout the run shear wise.
I meant on Doc's last blog entry.... Def not on this blog entry
Ah! Ok, was using the 80-85% jeffs713 posted.
Is there a page that states that stuff so I can bookmark it?
Two blobs to watch is way better than the AGW blog. Could this be the start of the big seasonal push? Most were predicting another 10 days or perhaps a week away yet, but this could be the beginning of something big. I was rather enjoying the lull, and I'm certainly not wishing any storms on anyone. But as a realist I understand that all that heat energy has to go somewhere. Just as long as it stays out of SE LA. Fish storms are better. I don't think the economy could take another big hit anywhere in the south.
Oh well, Bourbon is over by the ice bucket, help yourselves...
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