TD 2 struggling; new African wave bears watching
Tropical Depression Two is struggling. The depression still has a good chance of becoming the Atlantic hurricane season's first named storm this week, but the dry, Saharan air that surrounds the storm, combined with moderately high levels of wind shear, are interfering with the storm's organization. Satellite loops of the storm show that heavy thunderstorm activity is limited to the west side of the depression. This is due to strong winds out of the southeast that are creating a moderate 15 - 20 knots of wind shear. The intensity and coverage of these thunderstorms is meager, thanks to the large amount of dry air to TD 2's north that is getting wrapped into the circulation. This morning's QuikSCAT pass showed a well-formed surface circulation, with top winds of about 30 - 35 mph.
Wind shear over TD 2 is expected to remain in the moderate range, 10 - 20 knots, over the next five days. Sea Surface Temperatures (SSTs) are a marginal 26 - 27°C, and will not change much over the next three days. There is plenty of dry, stable air from the Saharan Air Layer (SAL) to to TD 2's north 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. However, it does appear likely that TD 2 has enough going for it that it will eventually be able to become Tropical Storm Ana sometime in the next three days. Most of the computer models show some weak development, but none of them predict TD 2 will become a hurricane. It is unusual for storms forming this far north to make it all the way across the Atlantic to hit the Lesser Antilles Islands. For now, TD 2 doesn't concern me as much as the new tropical wave to its southeast, just off the coast of Africa.
Figure 1. Tropical Depression Two (left center of image) and a new tropical wave (right side of image), newly emerged from the coast of Africa.
Elsewhere in the Atlantic
A strong tropical wave with some rotation and plenty of heavy thunderstorm activity left the coast of Africa yesterday, and is located a few hundred miles south of the Cape Verdes Islands. The GFS and ECMWF models continue to predict the development of this wave late this week. Both of these models indicate that the wave would track further south than Tropical Depression Two, and could impact the Lesser Antilles Islands in about seven days. This storm bears close attention over the coming days.
Two other tropical waves, one that just passed through the Lesser Antilles Islands, and one about 300 miles east of the islands, are mentioned in NHC's Graphical Tropical Weather Outlook. Both of these waves have very limited heavy thunderstorm activity that is not increasing, and are not a threat to develop over the next two days. None of the computer models develop either of these waves.
Felicia moves through Hawaiian Islands as a tropical depression
Tropical Storm Felicia weakened to a tropical depression before passing through the Hawaiian Islands yesterday. The storm brought scattered heavy rains of 1 - 2 inches to the islands, and no damage was reported. Felicia is only the 10th tropical cyclone of tropical depression strength or higher to hit the islands since 1950. Four other tropical cyclones have passed within 75 miles of the islands during that time period.
Be careful clicking on external links in blog comments
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I'll have an update Thursday morning.
Jeff Masters
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LMAO
Yeah. Very good point. A 48 hour forecast for Ohio (with upwind rawinsonde + plenty of surface data) > 48 hour forecast for the Lesser Antilles.
Also, the point about lateral boundary conditions and amplitude is interesting. I remember when I was running the WRF for my Thesis...there were all kinds of crazy, non-meteorologicl phenomena along the boundaries when I would use other models outputs for lateral boundary conditions.
Anyways, I'm out for the day. Enjoyable discussion...even though I've been removed from that stuff for quite a while!
You're right. I've been looking at Bill so much I forgot about her.
It's at a point of the day called DMIN, it's in the hours before sunset, and it's supposed to get weaker. It'll rebound at DMAX, where is gets stronger, while you are asleep.
Yep. 18z is the run to look at, its the most reliable. One slightly weaker run, now we can rest easier
There is no Bill...there's never been an "A" storm.
A lot of it will depend upon the trough that is expected to set up over the east coast by late next week. That is why the GFS continues to advertise an abrupt right turn in previous runs.
Nice crystal ball there... LOL
Try counting the isobars on the ECMWF 12z. That's like counting tree rings.
Of course there's no Bill.. this is going by the GFS run.. notice I have the quotation marks when I use those names.
I fail to see how one run, 150 hours out on the long range GFS after being constant with a strong tropical cyclone and all the other models are also showing hints at a strong cyclone means that we can 'rest easier'. It will most likely bring it back up the next run.
Whichever reaches TS strength first gets the name Guillermo, and it will work for Jimmy Kemmel.
show a ship report with a 1005.9mb reading in vicinity of the african blob
Yep. 18z is the run to look at, its the most reliable. One slightly weaker run, now we can rest easier
The 12Z and 00Z runs are the most reliable.
Not unless you'd like me to blow out both my eyeballs squinting at the computer screen, lol. They really need to post high resolution images like the NHC does with their models at NCEP.
WOW! 105.9 mb !?!
That ship must be at 40000 feet. What kind of ship?
Sorry. Really hard to hold that back.
EDIT: I see you modified...was really 1005.9 mb.
No. I know whichever comes first will get Guillermo. But let's say the one that was TD first gets Hilda. Will the NHC go Felicia-Guillermo-Hilda-Ignacio or Felicia-Hilda-Guillermo-Ignacio?
Notice the bridged High N of it preventing it from feeling the weakness fully.
Just now getting home and seeing this - Storm, I am so impressed with your veritable plethera of insul..uh, photos!
can i have the link to this info and the one for the E Pac
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2017 UTC WED AUG 12 2009
DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.
ATLANTIC OBJECTIVE AIDS FOR
TROPICAL CYCLONE TWO (AL022009) 20090812 1800 UTC
...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
090812 1800 090813 0600 090813 1800 090814 0600
LAT LON LAT LON LAT LON LAT LON
BAMS 14.3N 34.4W 14.4N 36.3W 14.7N 38.3W 15.0N 40.4W
BAMD 14.3N 34.4W 14.4N 36.7W 14.9N 39.2W 15.6N 41.4W
BAMM 14.3N 34.4W 14.4N 36.3W 14.9N 38.3W 15.3N 40.3W
LBAR 14.3N 34.4W 14.3N 36.8W 14.8N 39.6W 15.6N 42.5W
SHIP 35KTS 40KTS 45KTS 49KTS
DSHP 35KTS 40KTS 45KTS 49KTS
...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
090814 1800 090815 1800 090816 1800 090817 1800
LAT LON LAT LON LAT LON LAT LON
BAMS 15.4N 42.8W 16.9N 49.6W 20.0N 58.4W 23.7N 66.5W
BAMD 16.4N 43.8W 18.5N 48.9W 21.1N 54.6W 24.4N 59.3W
BAMM 15.8N 42.6W 17.3N 48.6W 19.6N 56.7W 23.2N 64.3W
LBAR 16.5N 45.4W 19.0N 51.1W 21.7N 56.8W .0N .0W
SHIP 52KTS 57KTS 53KTS 49KTS
DSHP 52KTS 57KTS 53KTS 49KTS
...INITIAL CONDITIONS...
LATCUR = 14.3N LONCUR = 34.4W DIRCUR = 265DEG SPDCUR = 12KT
LATM12 = 14.6N LONM12 = 32.0W DIRM12 = 265DEG SPDM12 = 11KT
LATM24 = 14.6N LONM24 = 29.9W
WNDCUR = 35KT RMAXWD = 50NM WNDM12 = 30KT
CENPRS = 1005MB OUTPRS = 1012MB OUTRAD = 150NM SDEPTH = M
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 50NM
Agreed, very zonal - northern branch of jet has a small dip, but not enough to effect this system
The first one. And how come you didn't get my Jimmy Kemmel joke?
I'm sorry, I just have to...
It's not bridged yet. There is still a bit of weakness in the mid levels
http://www.srh.noaa.gov/product_sites.php?pil=CHG&max=61
Hehe... looked bridged enough.
Because I've never heard of Jimmy Kemmel.
I'm guessing with such an extreme area of low pressure it won't take much for this blob to organize and get the NHC's attention
*looks at hurricane list, Beer, check, batteries, check, ping pong balls, check...*
href="http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/18/fp0_240.shtml" target="_blank">Link
note it was a typo guys come on you know better.
Quoting atmoaggie:
OK, a little clarification. The NAM, aka WRF-NMM uses it's own forecasts, corrected by availa1ble obs as initial condition fields...think Cressman or Barnes analyses (mostly Cressman). It uses GFS only for lateral boundary conditions...as in features propagating into, or out of, the NAM domain.
This isn't as bad as it sounds. GFS is quite good at synoptic-scale features forecasted days into the future. (I personally think it is a little goofy side, but, again, what can you do when a short-run model is needed without waiting for the most recent global model to run).
Big caveat: If GFS hasn't the foggiest idea that amplitude of said feature moving into NAM's domain and there are no obs, forget about NAM having a good solution. This is partly why NAM is fairly adept at a 2-day forecast on land in North America. Using for something else? Best of luck.
Yeah. Very good point. A 48 hour forecast for Ohio (with upwind rawinsonde + plenty of surface data) > 48 hour forecast for the Lesser Antilles.
Also, the point about lateral boundary conditions and amplitude is interesting. I remember when I was running the WRF for my Thesis...there were all kinds of crazy, non-meteorologicl phenomena along the boundaries when I would use other models outputs for lateral boundary conditions.
Anyways, I'm out for the day. Enjoyable discussion...even though I've been removed from that stuff for quite a while!
I know everyone understood exactly what you 2 was talking about here......i sure the hell didn't.....LMAO
Link
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