TD 2 nearly dead; African disturbance 90L gathering strength
Tropical Depression Two is near death, but is still worth watching. The dry, Saharan air to the north and west of the depression, combined with moderately high levels of wind shear of 15 - 20 knots, have almost completely destroyed all of TD 2's heavy thunderstorms. Satellite loops of the storm show a well-formed circulation, but almost no heavy thunderstorm activity.
Wind shear over TD 2 is expected to remain in the modereate range, 10 - 20 knots, over the next five days. Sea Surface Temperatures (SSTs) are 27°C, but will warm to 28°C three days from now. There is plenty of dry, stable air from the Saharan Air Layer (SAL) to to TD 2's north and west that will continue to cause the storm problems. The relatively cool SSTs and dry air mean that TD 2 will not be able to intensify quickly, and some of the models indicate the TD 2 may get destroyed in the next day or two. However, several models still predict TD 2 will become a tropical storm. The HWRF model predicts TD 2 will become a hurricane five days from now, but this seems unlikely given the dry air and relatively high wind shear affecting the storm.
Figure 1. Tropical Depression Two (left side of image) and tropical wave 90L (right side of image).
African tropical wave 90L
A strong tropical wave with a large circulation and plenty of heavy thunderstorm activity is a few hundred miles south of the Cape Verdes Islands, off the coast of Africa. NHC dubbed this disturbance 90L this morning. This morning's QuikSCAT pass shows that 90L has a very large circulation, and top winds of about 30 mph. Satellite imagery from the European METEOSAT satellite show that the heavy thunderstorms associated with 90L are in two major bands, to the north and to the south of the center. There is no heavy thunderstorm activity near the center yet, and this would have to happen before 90L can be named Tropical Depression Three. Water vapor imagery shows that since 90L is forming several hundred miles south of the dry air of the Saharan Air Layer (SAL), the storm should not be affected by dry air and dust as much as Tropical Depression Two has been. Wind shear is about 20 knots over 90L, and is forecast to remain in the moderate range, 10 - 20 knots, over the next five days. Sea Surface Temperatures are about 28°C, and will remain in the 27 - 28°C range the next five days, which are high enough above the 26°C threshold for tropical cyclone formation to allow some slow development to occur. The GFS and ECMWF models continue to predict the development of this wave, though they are now less aggressive about intensifying it than they were in earlier runs. The consensus among the reliable HWRF, GFDL, GFS, and ECMWF models is to bring 90L to point near or just north of the northernmost Lesser Antilles Islands 6 - 8 days from now. The storm could be at hurricane strength by then, as forecast by the SHIPS intensity model.
I'll have an update Friday morning.
Jeff Masters
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yeap and ikes post looks spooky too
See the overnight 0z GFS does not think much of the potential east coast trough. Has 90L in the Gulf still after slamming the Islands.
If you do not like the results of that GFS run just stick around a little longer... The next could be to your, or someone else's liking... LOL
I just can't believe the consistent NOLA landfalls projected by the models.. That is, however, usually a good sign because, as we all know, these models adjust over time and are almost never correct with their initial assessments.
True! It could be a record though - two runs in a row with basically the same destination. :)
It has gone up to 1.5 on the Dvorak and strangely, 02L has just reappeared on the Dvorak from SAB for 1.0 too.
90L has dropped a millibar to 1008, but that's all. Still at 25kts.
Plus there's no ATCF renumbering which is generally a good indication.
I'm showing a 1.1 now for 02L.. It's like the little engine that could :)
For the ADT, yup. Guess that's basically just admitted 'it's there'. But yeah, it's like li'l 96L of '07 all over again.
Chugging away despite dry air and shear. May have the same result, though.
90L looks rather impressive this morning. also ex TD4 is trying a comeback. for the ist time it is surrounded by a moisture field
Tropical Cyclone Advisory #8
SEVERE TROPICAL CYCLONE GUILLERMO (EP102009)
9:00 AM UTC August 14 2009
====================================
At 6:00 AM UTC, Hurricane Guillermo (987 hPa) located at 17.6N 125.9W or 955 NM west-southwest of the southern tip of Baja California Peninsula has sustained winds of 65 knots with gusts of 80 knots. The cyclone is reported as moving west at 13 knots.
Hurricane-force Winds
=====================
15 NM from the center
Gale/Storm-force Winds
================
90 NM from the center
Forecast and Intensity
======================
12 HRS: 17.9N 127.9W - 70 knots (SSHS-1 Cyclone)
24 HRS: 18.4N 130.5W - 70 knots (SSHS-1 Cyclone)
48 HRS: 19.6N 135.7W - 55 knots (Tropical Storm)
72 HRS: 21.0N 141.0W - 45 knots (Tropical Storm)
Looks like it's slowly trying to make itself an eyewall.
Tropical Disturbance Summary (0600z 14AUG)
=========================================
SUBJECT: Tropical Depression In Sea East of Marshalls Island
At 15:00 PM JST, Tropical Depression, Former Maka (1008 hPa) located at 13.4N 177.1E has 10 minute sustained winds of 30 knots with gusts of 50 knots. The depression is reported as moving west-southwest at 7 knots.
It appears the ECMWF is the outlier here 456. Look how tight the models are, the ECMWF is the only one sending it out to sea.
456 - do you know why the models are in such agreement? I don't ever remember seeing them do this before.
Ridge of high pressure to the north might end up being stronger than originally forecasted by these models.. then again its a weeks forecast, I honestly would take it only with a grain of salt "for now".
yea i notice, it is becuz it has 90L slower feeling more of a weakness.
However, ECMWF is the one that has done the best this year IMHO. Keep on praying 456.
The SAL and dry air is almost gone, I listened to the Bob barometer last night and he agreed with that. An anticyclone is moving in tandem with 90L too, protecting it from shear.
All the way with it?
High Sea Forecast for the eastern Atlantic
---------------------------------------
Strong tropical wave along 24W south of 20N moving west near 10 kts.
Associated low 1010 near 12N, expected becoming tropical depression in the next 24H or 48H.
Yessir.
Then for sure, that'll help!
The Euro may make it slower too because it's not hinting at as strong of a high as the GFS is.
Both are pushing the centre (maybe because of the trough?) off towards the Azores though.
link
I cant get much out of the NOAA site
still taking in all the dry air infront of it you see it here
Link
Question: I have never understood the deal with the Anti Cyclone building On Top of the opposing cyclonic rotation below, and how that even works, much less how it actually Helps a Tropical Cyclone to build... seems to be something to do with reducing the effect of Wind Shear on the the TC, maybe. If so, how so, any clarity here would be helpful. Thx.
(I can give you more on this if you want. Didn't want to jump right in with more info than you wanted/needed.)
Nothing too earth shattering. Tallahasee and Miami were the ones to speak of 90L the most.
http://www.scienceclarified.com/Co-Di/Cyclone-and-Anticyclone.html
Try that out.
Yea, but 90L is much more south than TD2.
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