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Santa Ana winds ease; tropical wave nearing Puerto Rico could develop

By: Dr. Jeff Masters, 2:24 PM GMT on October 24, 2007

A surface low pressure area has developed near 17.5N, 60.5W, about 150 miles east-northeast of the northernmost Lesser Antilles Islands. This morning's QuickSCAT pass showed an elongated circulation that is not well organized. Top winds were about 25 mph to the northeast of the circulation center. Winds in the northern Lesser Antilles Islands were less than 10 mph this morning, but pressures have been falling for the past two days. Satellite loops show little heavy thunderstorm activity--less than yesterday. However, this activity appears to be increasing just north of the circulation center this morning.

Wind shear has dropped to 10-20 knots in the region, and some slow development of this system is possible as it moves to the west at about 5 mph. This westward motion is forecast to bring the low over Puerto Rico Thursday night and Friday morning, then to a point between Haiti and Jamaica on Saturday. All of these islands can expect heavy rains during passage of this system. Both the ECMWF and NOGAPS models develop the disturbance into a tropical depression on Saturday near the southern coast of Haiti. The GFS models does not, because of high wind shear. All of the models forecast falling pressures and low wind shear over the Western Caribbean late this week and early next week, and it would not be a surprise to see a tropical depression form in the region. Today is the 2nd anniversary of Wilma's strike on South Florida, so powerful hurricanes are still a concern at this point in the season. Wunderblogger Mike Theiss has posted a blog today recounting his experiences in the eye of Wilma.

Heavy thunderstorm activity has increased in the central Caribbean south of Haiti this morning. There is some rotation evident at mid levels of the atmosphere in satellite loops, but QuikSCAT showed no evidence of a surface circulation in this morning's pass. This disturbance will need to be watched for development. Activity in the western Caribbean between the Yucatan Peninsula and Cuba is associated with a cold front.

California's fires
Surface maps show a high pressure system centered over Nevada and Utah. This high is weakening and moving eastward away from California. The clockwise flow of air around this high is still driving northeasterly Santa Ana winds over Southern California, but these winds are much weaker than yesterday. By Thursday, the Santa Ana winds will be gone, to be replaced by a weak flow of moist air off the ocean. The new weather pattern will bring increased humidity, cooler temperatures, and lighter winds, which should allow firefighters to gain the upper hand. The long range forecast shows light winds for Southern California for most of the coming week, but no rain, and not as much onshore ocean winds as firefighters would like to see.

Figure 1. Visible satellite images from Monday and Tuesday with satellite-derived particulate air pollution levels overlaid. Image credit: NASA and EPA.

Air quality
Air quality due to particulate matter continues to be awful in Southern California (Figure 1). Exceedances of the Federal air quality standards by more than a factor of two have occurred the past four days in both Los Angeles and San Diego. The air pollution problem is expected to linger for several days after the fires are out. The onshore winds that are expected to form will recirculate smoke that is over the ocean back over land. As seen in a vertical cross section of the smoke taken by NASA's Calipso satellite Monday (Figure 2), smoke from the fires has stayed confined to the lowest 1 km (1,000 meters) of the atmosphere over the ocean regions southwest of San Diego. The cold waters of the California Current creates stable air above it that resists moving upwards, keeping the pollution trapped near the surface. However, some of the smoke is expected to rotate clockwise along the California coast, moving back over the U.S. over the northern half of California Thursday and Friday. Trajectory forecasts indicate that this smoke will be lifted as it circulates back over the U.S, thanks to the lifting motion associated with the low pressure system approaching the Pacific Northwest. The smoke should color sunsets over much of Northern California and northern Nevada over the next few days, but should not cause significant pollution problems at the surface, since most of the smoke will be aloft.

Figure 2. Altitude of smoke as measured by NASA's Calipso satellite at 3:07 am PDT Monday Oct 22. Calipso uses a LIDAR (LIght Detection And Ranging) to detect particles suspended in the atmosphere. Lidar is like radar, except that it uses a visible light beam instead of a radar-wavelength beam. Image credit: NASA.

The University of Wisconsin's CIMSS group has another excellent blog on yesterday's fires, complete with satellite animations and detailed analysis.

San Francisco Climate Challenge
Today is the last day for San Francisco residents to sign up for the San Francisco Climate Challenge, an innovative contest designed to encourage residents to reduce energy usage. The content offers prizes up to $5000 for those residents able to reduce their energy consumption the most over the coming month. For more information, see the new Weather Underground climate page at http://www.wunderground.com/climate/.

Ricky Rood has posted a blog this morning on the ongoing Georgia/Southeast U.S. drought.

Jeff Masters
Yet the fire was still miles away....

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

Actually.. I think Arnold asked for them.
That's a pretty picture Pat. I'll bet that drop wasn't being made in a high wind condition, tho.
Isn't the Canadian air tanker in Ca. owned and operated by a private contractor? Does anyone remember seeing that info?
Evenin yall. How are things.
Looks like there is a healthy circulation coming off Central America SW of Cuba on the WV loop.


Hi Baroness, how are the mare and the other gentle beasties?
Yes, the tanker is owned by a Forest company here on Vancouver Island. They are based out of sprout lake near Victoria during fire season.
Flaboy, jazzy is doing great. We let her out after 4 weeks of confinement. She was really happy. I have to still take her into the vet for a check, and it is still a deep injury, but she is healing and thank gawd she isn't lame. Other critters are good. jazzy is such a bossy b....ch, I think they hated to see me let her lose.

Thanks for asking.

510. BtnTx
I didn't get to see Patrap's Water Bomber pic. Why is this. Didi it get deleted because I am too late?
511. BtnTx
Thanks to Orcasystems post I was able to paste into browser and get info on MARS flying tankers.
Is this a seasonal blog?
513. BtnTx
512. sporteguy03 10:35 PM CDT on October 24, 2007
Is this a seasonal blog?

It looks like most people write about what's going on now to me...
Hmm if this worked... it may show a picture

Orcasystems, thanks for the link. I got lost in there for a while. Those aircraft boggle the mind. The fuel requirements are 265,000 gals. for 6 hrs. I saw some complaints about the price of fuel. I think I'll stick with my pickem up truck.lol
Btn Tx, try Orca's link and click on the gallery. They have several awesome shots in there.
265,000 gallons, or litres?


7500 Gallons for 5.5 hours
517. Orcasystems 11:55 PM EDT am 24. Oktober 2007 Hide this comment.
265,000 gallons, or litres?

The spec sheet said 265,00gals. or 1,000,000 ltrs. for 5.9 hrs of operation per aircraft. Four engines @ 2,500 hp each.
Baroness, I'm glad the critters are OK. Things get hopping and we end up forgetting about the other residents of this ball of rock.
Orca, I think I read the wrong line. I think the number 265,000 gals was the maximum water delivery
for ideal conditions. It looks like the fuel consumption would be around 4,800 gals for 5.9 hrs. Me mess up bigtime.
521. BtnTx
Hopefully weather will change and fire situation will change in CA soon!!
505. flaboyinga 11:22 PM EDT am 24. Oktober 2007
Looks like there is a healthy circulation coming off Central America SW of Cuba on the WV loop.

I'm gonna try the link thing one more time. I couldn't get it to work before. Anyway the circulation is still there.

523. BtnTx
flaboyinga link did not work for me and I do not know what the trick would be to get it to work
Oh well. Here's the copy and paste address of the Water Vapor loop for the caribbean.

It should be Link

I'll be damned.. it worked
526. BtnTx
flaboyinga - yes I see the major circulation. The cut and paste type link seems to be very reliable and not that hard to do IMO.
Orca did you see my correction on the fuel consumption? The fist number would probably fly the space shuttle int orbit.lol
Death toll in Gulf oil rig accident rises to 18, 7 missing That storm closed all the major Mexico GOM oil ports for near 2 days.
529. BtnTx
Skyepony - first I have heard of this oil rig incident... Thanks for info
Skyepony, thanks for the link. We sure need to count our blessings that we are not in harms way at the moment, as so many people in other areas are.
The wind shear over the W Caribbean and north of
Puerto Rico doesn't look to bad on this link. There might be some development in both areas.

Here's a 36 hr wind shear chart for the West Atlantic. If it works. lol

That Mexican rig is in the area where the small but deep pacific swirl crossed into the gulf and then flared up when it got thwacked by the cold front. (It's now moved back inland, but it sat offshore for quite a while wreaking havoc.)
jp, it looks like you're keepin an eye on things.
No hurricane for you! Come back ... 10 months!

The current low is a loooooong shot. Waters cooling, cold fronts working all the way down to the GOM. Don't see it happenin.

The Hurricane Nazi
536. IKE
Wilma of 2007?

Ike.. damnit... none of that now... I want to be DONE for the season, I just got my bulkhead repaired and backfilled with new sod laid and finished.. I'm not ready to give it up to Indian River again...yet.
5kt shear near the Equator!! This is not happening...I hope...
GEM model going with the EURO model on its idea....

Would like to see jeff masters thoughts on the models later this morning. Adrian
The GEM, NOGAPS, and ECMWF may be on to something.
good morning

St Kitts reporting SW winds @ 9 mph and low level inflow is clearly visisble in this image from Ramsdis

The low over the NE Islands is better organised than last night. It will need to track S of Hispaniola though to stand a real chance of developing as right now it is on a course to cross over a lot of high terrain.
Atlantic Floater 1 http://www.nhc.noaa.gov/satellite.shtml
INVEST on dvorak site north of antilles, not on navy site yet

I see the floater up now
Shear map looking hostile but other systems have defied high shear this season and spun up anyway
This mornings models are showing signs of some sort of tropical development near PR and moving generally WNW to near Cuba or FL Straits this weekend. The CMC, NAM, NOGAPs, FSU MM5, and GFS all show low pressure development.

I looked at several of the model runs and at least 3 had a low coming WSW from where the invest is now into the W Caribbean.
Two had fairly strong 990mb systems passing either just S or E of the Caymans.
HI Storm

Looks like the season is coming back to life a bit. Waiting on QS to also see how the SW Caribbean looks at the surface. The descending pass last night showed a very broad low over the entire area from Panama to 15N
There is a high building near there so IMO we should also keep an eye on that area today
Feds Join Arson Probe in California Blazes

Posted: 2007-10-25 06:42:34

Filed Under: Nation News, Natural Disaster

LOS ANGELES (Oct. 24) - Federal agents joined the search for evidence Wednesday in brush-covered Orange County hills where an arsonist is believed to have ignited one of the wildfires devastating Southern California.

In San Bernardino County, a man suspected of starting a small fire was arrested and another man was shot to death by police after he fled officers who approached to see if he might be trying to set a fire.

Wildfires, burning in seven counties, had destroyed about 1,500 homes and caused more than a half-million people to flee since the first blaze began late Saturday. At least two — in Orange and Riverside counties — have been linked to arson.

Throughout the region, authorities stepped up patrols in hopes of preventing copycat fires and looting. In San Diego County, sheriff's officials have reported scattered instances of looting in fire zones. Two people have been arrested.

Orange County officials converged on a remote area of bone-dry brush where a 19,200-acre wildfire has destroyed nine homes. They were aided by special teams from the FBI and federal Bureau of Alcohol, Tobacco, Firearms and Explosives. The federal government planned to send more agents from around the country to help with the probe.

Investigators taped off an area they called a crime scene, took photos, collected evidence and recorded map coordinates, according to ATF Special Agent Susan Raichel. Authorities believe the fire had been set because they found three different ignition points within a short distance — a common sign of arson.
quikscat missed the invest but shows a weak low off the Honduras/Nicaragua border
A wait and see day today for both areas
I am off for now but will BBL

Have a great day everyone
Interesting point there Storm, but I hope you are wrong for a change LOL
if we are in fact running 2 weeks behind, based on September, then October may be peaking now.

Good point, StormW...I'm no professional, but the patterns are all looking at a 2-3 week lag in the season from it's "average" calendar points

Good morning, by the way. How are you?
Just say NO!

To late season tropical developement.

Remember, the first step to overcoming a problem is to admit you have it in the first place.
Good! How about you?

Not too bad...trying to coffee up for my day...

Just got into the office here in beautiful DFW, getting my morning fix of the the tropics
Mornin' Jerry....Mornin' Storm....

Just got into the office here in beautiful DFW


WHOOSH, over my head.....

567. IKE
San Juan,PR discussion.....

"Discussion...quite an interesting and challenging forecast...but
looks like UKMET...European model (ecmwf) solutions of recent days are playing out.
L/west trough across central Atlantic will continue to dig SW through the
weekend and force the deep layered elongated low west-southwest today and then
more SW overnight through Saturday night. The low to middle level
circulation will eventually detach and move across PR tonight and
then pass S of Hispaniola Friday through Sat night. Strong pressure
gradient induced by large high across the west Atlantic will produce
strong winds potentially nearing gale force across north quads of low
as it shifts across the area...with these winds expected to
remain across the offshore Atlantic...and possibly north Mona Passage.
Best moisture...and associated squalls and thunderstorms will move into
the local islands late this afternoon through Sat...occurring all
around the north and eastern periphery of the low."
Wonderful surprise this morning - cool and breezy! Guess the cold front got here after all.

Morning all.
571. IKE
jphurricane2006 7:53 AM CDT on October 25, 2007
Invest 90L, up on the Navy site

It's about time.
A good day to one and all.
566. NRAamy 7:49 AM CDT on October 25, 2007
Just got into the office here in beautiful DFW


WHOOSH, over my head.....


Morning, Amy...Dallas-Fort Worth; I've been a bit of a nomad these past few years, following my job: South Florida for most of 2004, south Louisiana for 2005-2006, and now Dallas (home office)
574. IKE
Puerto Rico has a 60-70 percent chance of rain through Saturday night.
569. jphurricane2006 7:53 AM CDT on October 25, 2007
Invest 90L, up on the Navy site

And so it begins...morning, jp, how are you?
Morning everyone. Here's to days off!!! [salutes with cup of coffee]

I see we have some limited (for now, anyway :o) tropical activity in the basin. Should be interesting to see what spins up over the next 5 days. Best of all, I have an extra "free" day to sit around and blog about things!
Completely agree with the pattern 2-3 weeks behind,weather here in new england has been more like early Oct.- late Sept.
And good morning.
Amy I watched the news this morning,more encouraging for you people out there,winds are dying down.Hope the end is in sight.
90L also up on NHC floater.
Storm, I've been watching a circulation that recently came off of central america that is now almost due south of the western tip of Cuber. Do you think there's any chance that will develope? I have only looked at it on the WV loops.
Per local ABC news:

Irvine, Calif. fires are now only 40% contained....$70,000 reward offered for info leading to the arrest of the arsonist....
jp, where is 90L and what is the preliminary track?
Looks as though the CV feature from yesterday has lost a good deal of it's convection; there does appear to be another wave just off the African coast:

Morning Amy!

You doin' OK?

I need a new nose....too much smoke...

588. beell
Good Morning Worldville. Houstonians are missing Summer already.

Gotta like that area at 18N 84W.
If anyone missed the photos Patrap and others posted of the Canadian Company's air tankers the link is below. They are something to see. If the wind and other flying conditions will cooperate, Calif. is gonna get some rain on their fires.


Where would I find a link for the Navy site?
Which of the 3 BAMM models has most credibility?
Good morning, StormW, all.

Yeah, shear still rules. The ull to its ne is also pulling convection away from the low. I doubt development is really possible. If at all, would probably take place further west as the wave tracks into the wCarib.
590. StormW 9:18 AM EDT on October 25, 2007 Hide this comment.
583. flaboyinga 9:07 AM EDT on October 25, 2007
Storm, I've been watching a circulation that recently came off of central america that is now almost due south of the western tip of Cuber. Do you think there's any chance that will develope? I have only looked at it on the WV loops.

At this time, I don't feel it will...unless it pulls a track like Lenny did a few years ago, it should stay under some fairly decent shear. I'm gonna watch it though as crazy as this season's been.

It doesn't look like much right now, but the shear is down and the water is still warm and there seems to be plenty of moisture available to it. Kinda makes me wonder what it'll do.
Orca, try this.

596. V26R
Morning All
Whos got the donuts???
Correction: The Irvine, Calif. fires are only 30% contained....fires are spreading into the Cleveland National Forest....

Calgon, take me away....
596. V26R 9:28 AM EDT on October 25, 2007 Hide this comment.
Morning All
Whos got the donuts???

I got my danish wedding cookies. (no cholesterol) I could stick a few in an envelope. lol
90L t numbers

25/1145 UTC 19.3N 63.1W T1.0/1.0 90L -- Atlantic Ocean

jo ^_^
Orca, I found another link to the Navy. Yhis is probably better than the other one.

600. flaboyinga 1:34 PM GMT on October 25, 2007
Orca, I found another link to the Navy. Yhis is probably better than the other one.

Thank you :)
Good Morning all

Here is a closer view of 90L

Looks to me on the last few satellite loops the shear is relaxing a bit
601. Orcasystems 9:36 AM EDT on October 25, 2007 Hide this comment.
600. flaboyinga 1:34 PM GMT on October 25, 2007
Orca, I found another link to the Navy. Yhis is probably better than the other one.

Thank you :)

Click on models on the left side and there's some interesting stuff there.
So we're back to the donuts this morning.
606. V26R
Hey NEWX What type of morning would it be without them???
605. NEwxguy 9:41 AM EDT on October 25, 2007 Hide this comment.
So we're back to the donuts this morning.

Nah, that was on the previous page.
Morning all. Flaboy, I love those cookies! Flood what in the heck do you do for a living that takes you to all of those exotic places. Remember I was born and raised in FW.

So we have another invest? Ohh my.
Baroness, I was hooked on pecan sandies until my bride pointed out the cholesteral numbers and put the "spoken word" on me.
NRAamy, the fires are dreadful and hope that all of you get some relief there soon! Stay safe.
"Wilma of 2007?"

Ike ssts arent warm enough for a wilma. More like an Irene though.
Wilma also formed farther west, had lots of time to strengthen due to slow erratic movement in Carrib. Irene formed along a stalled cold front under SW shear. Moved NE fast enough that relative shear was nullified. Strengthened over everglades.
612. V26R
Anyone know if QUICKSAT hit 90L this morning?
613. V26R
Ivan what is Ivans Cat saying about 90L this morning???

...a miss apparently.
615. V26R
Figures MLC
Thats two days in a row
morning,v26,coffed and donuts mix well with invests this morning,looks interesting the coming week.
617. V26R
As long as everything stays well south of us
BTW Congrats on last nites Victory
618. IKE
Not sure I believe the BAM models of 90L going over DR/Haiti....that would tear it apart though.

SHIPS only goes up to 48 knots in 96 hours on 90L.
619. IKE
V26R 8:53 AM CDT on October 25, 2007
As long as everything stays well south of us
BTW Congrats on last nites Victory
The Red Sox are too good. A sweep is possible.
I agree with storm's analysis. Topography of Belize/Honduras also supports cyclonic winds during daytime. Winds head for shore during daytime. Belize faces east, Honduras north. almost perfect 90% turn. Thats half a closed low by itself. big part of why that area supports early and late season development. BBL!
617. V26R 1:53 PM GMT on October 25, 2007
As long as everything stays well south of us
BTW Congrats on last nites Victory

Thanx,it was pretty ugly,should be a different story tonight.
I thought we were done for the year.What are the feeling of 90 becomeing anything?
618. IKE 8:55 AM CDT on October 25, 2007
Not sure I believe the BAM models of 90L going over DR/Haiti....that would tear it apart though.

SHIPS only goes up to 48 knots in 96 hours on 90L.

Given the steering, a miss of Hispaniola to the south would be more believable
619. IKE 1:56 PM GMT on October 25, 2007
V26R 8:53 AM CDT on October 25, 2007
As long as everything stays well south of us
BTW Congrats on last nites Victory
The Red Sox are too good. A sweep is possible.

Its only the second game,but I think its a must game for the rockies tonight.
625. IKE
NEwxguy 8:56 AM CDT on October 25, 2007
617. V26R 1:53 PM GMT on October 25, 2007
As long as everything stays well south of us
BTW Congrats on last nites Victory

Thanx,it was pretty ugly,should be a different story tonight.

Yeah...the SOX win this one by 5 runs vs. the 12 they won by last night.
Cat is still in her (indoor) tree snoozing. I'll let you know when she wakes up.
Current weather here in St Barths in the Northern Leewards (18N63W)

Barometric pressure : 1007mb;
Cloudy sky with CB clouds to the north and east;
Light westerly winds with some gusts at time.
628. IKE
Convection is firing over 90L.
629. V26R
Going to be an interesting series
Hope the wind isn't blowing too hard when they get to Denver!
631. V26R
Buddies down on Antigua said that last night was the most calm and humid night there so far
Very strange no breezes, maybe the calm before the storm?
Morning folks :)
morning BAJA