California fires and global warming; 90L lashes Puerto Rico
A surface low pressure system (90L) moved over Puerto Rico this morning, and is now centered just west of the island. The surface low is entangled with an upper-level low pressure system that is bringing about 30 knots of wind shear, so no development is likely today. Long range radar of of Puerto Rico shows isolated bands of heavy rain that are not well-organized. Satellite loops show most of the heavy thunderstorm activity is to the east of the low's center of circulation, and the high wind shear is keeping this thunderstorm activity disorganized. This morning's QuikSCAT pass showed a large, vigorous circulation. Top winds were about 30 mph to the north of the center, and 90L is close to tropical depression status.

Figure 1. Latest satellite rainfall estimate of 90L.
The surface low is separating from the upper level low today, and will move west-southwest at about 10 mph. This will bring heavy rains and the threat of flash flooding and mudslides to Puerto Rico. Heavy rains of 2-4 inches in just two hours hit the Virgin Islands this morning (Figure 1), prompting flash flood warnings there. Heavy rains also hit many of the islands of the northern Lesser Antilles. Rain amounts as high as 3-5 inches are expected today over eastern Puerto Rico. Several mudslides have already been reported on the island.
The action shifts to the Dominican Republic on Saturday and Haiti on Sunday, as 90L tracks just south of the island of Hispaniola. These nations can expect rains of 3-6 inches, which could trigger life-threatening flash floods and mudslides. It is possible 90L could intensify into a tropical depression on Sunday, as wind shear will slowly fall to 20 knots. The Hurricane Hunters are on call to fly Sunday afternoon, if necessary. On Sunday, 90L will be approaching Jamaica, and the ECMWF and NOGAPS models predict that wind shear will drop to 10-20 knots. These models develop 90L into at least a strong tropical storm as it moves slowly into the Western Caribbean. The GFS model keeps wind shear 20-30 knots through the period, and does not develop 90L. The HWRF model also does not develop 90L. The GFDL is not keen on developing the system either, but does suggest that a weak tropical storm may form a week from now. I believe the most reasonable solution is the NOGAPS and ECMWF solution, and 90L will intensify into hurricane in the Western Caribbean late next week. The long-term path of such a storm is very uncertain, with the NOGAPS and ECMWF suggesting a track north into the Gulf of Mexico to threaten the U.S., and the GFDL predicting 90L will get trapped in the Western Caribbean and perform a counter-clockwise loop. If you have travel plans that take you to Jamaica or the Cayman Islands Sunday through Tuesday, or Cancun/Cozumel/Western Cuba Tuesday through Saturday next week, be prepared for the possibility of disruptions.
California's smoke
The worst of the air pollution hazard from California's fires has now passed. The smoke has thinned some, as seen on satellite images (Figure 2). The smoke made it yesterday to Fresno, in California's Central Valley, and is moving northward into Nevada and northwest Arizona today. Most of this smoke is aloft at altitudes of about 15,000 feet, but some mixing down to the surface has occurred, thanks to an upper-level low pressure system. Increases in particulate matter pollution due to smoke are expected to affect Las Vegas this weekend (Figure 1). However, the smoke will be dilute enough to keep pollution levels in the Moderate range--below the federal air quality standard.

Figure 2. Visible satellite image at 11:15 am PDT Thursday October 25, showing thinning smoke over the Pacific Ocean and much of California. Low stratus clouds are visible over the ocean, and these clouds have moved ashore into Los Angeles and San Diego this morning, triggering Dense Fog Advisories. Image credit: NASA and EPA.
Were the California fires worsened by global warming?
Dr. Ricky Rood points out in his latest wunderblog that the California fires were mostly a land-use and land-management issue. In a previous blog, he had this to say about the link between climate change and Western U.S. fires:
We do know that drought and floods, heat waves and cold snaps are all part of nature. Like the problem of urban heat waves, we have an event that already exists, and there should be a change associated with global warming. I have already mentioned that some studies have attributed the pinyon pine die off in the U.S. Southwest to the fact that the temperature in the recent drought years is higher than in previous droughts. Therefore, ground water is reduced; there is more stress on the plants. (And perhaps it is really the warmer nighttime temperatures that matter?)
There have also been papers which make a compelling argument that wild fires in the western U.S. are increasing in intensity and duration. In the paper of Westerling et al. (Science, 2006), the conclusion is drawn that this is directly related to snow melt occurring earlier in the year, a hotter and drier forest, and hence, a longer burning season. Plus they isolate the impact to be at mid-elevations in the Rockies, and hence, relatively free of land-use changes. While many newspapers reported that this work showed an increase of wild fires due to climate change, I quote directly from their paper: "Whether the changes observed in western hydroclimate and wildfire are the result of greenhouse gas-induced global warming or only an unusual natural fluctuation is beyond the scope of this work".
Jeff Masters
Reader Comments
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Click to ENlarge
GOM and Western Carb..Link
PRESSURE HAS FORMED OVER THE NORTHWESTERN CARIBBEAN SEA. LITTLE
MOTION IS ANTICIPATED AND ADDITIONAL DEVELOPMENT...IF ANY...WILL BE
SLOW TO OCCUR.
ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.
This is the area (already on the NWS radar)I am talking about and it looks like it is trying to get much better organized this afternoon.....
Any comments on this system forming south of Cuba? Patrap posted a great Sat shot of this system. I can't access any NHC sat loops cause my browser shuts down (ahh, the joys of working behind a large corporation... *sigh*). I know it's pretty silly to attempt to decipher a COC around this thing, but I think I see some rotation on one of the southern blobs... am I right? or was that pint with lunch a little too strong?
good I just got 3 yds of dirt delivered this morning, I've been hauling it to the backyard all day, trying to beat the rain...Dont want a mud pit.
hey..anyone here like wrestling? ha!jk....
shadow,looked at the projections right now the heaviest precip is through eastern penn.,east & cen. NY and the western part of new england.
good I just got 3 yds of dirt delivered this morning, I've been hauling it to the backyard all day, trying to beat the rain...Dont want a mud pit.
hey..anyone here like wrestling? ha!jk....
growing up,use to take mud baths.
mmm...lunchpints...aauuggghh!!! *drools like Homer*
Howdy CF...I think theres some coc development there on 90l...the swirl is nearly naked...got underoos on, anyways...
yeah I have 3 little ones here that are very interested in trying that out... Its my intention to prevent such bathing from occuring...
Here's the RGB loop of 90L:
From what I can see 90L has a vigorous surface circulation and the area of disturbed low pressure in the Western Carib does not. That doesn't mean it won't....it just doesn't right now.
growing up,use to take mud baths.
yeah I have 3 little ones here that are very interested in trying that out... Its my intention to prevent such bathing from occuring...
mom,your no fun,bet ya one of them finds their way to the mud
GOES-12 CH-4 WV False Color Image from 17:32 UTC
Click to ENlarge
GOM and Western Carb..Link
Thats crazy! The whole network of systems looks like the "L" in Laverne's shirt!
I am a complete believer in anthropomorphic global warming but I don't see any reason to believe the current cycle of extreme weather in California is caused by that. In fact, we had a VERY similar rainfall pattern in the 1880s, including a year of extremely heavy rain (like 2005) followed by a year of very extreme drought (like 2007). Although we didn't have a lot of weather stations back then, there is very strong evidence that California just has an extreme climate, and has for the last 10,000 years at least.
Remember, it rained 36 inches in 2005-2006. If you average the rainfall for the last few years, it actually comes out as 'above average'. In the late 1800s (probably associated with that other drought cycle), there is documentation of a fire that started somewhere near big bear and burned TO THE OCEAN. This is over 80 miles! The drought cycle is the same as it has always been, but now we have homes and eucalyptus mixed into the chaparral.
Any thoughts?
lil' jet stream action...
A COUPLE OF LOW PRES AREAS ARE ANALYZED IN THE REGION THIS
AFTERNOON. IN THE E CARIB...A WSW MOVING LOW IS CENTERED TO THE
SW OF PUERTO RICO NEAR 17N68W...ANALYZED 1006 MB. THIS LOW HAS
NOT BECOME ANY BETTER ORGANIZED TODAY AS THE LOW-LEVEL
CIRCULATION IS WELL EXPOSED W OF THE DENSE CLOUDINESS. THE MOST
ACTIVE AREA OF CONVECTION IS FAR TO THE E OVER THE LESSER
ANTILLES FROM 13N-18N E OF 64W. THIS PRECIP IS BEING ENHANCED BY
A SMALL UPPER LOW LOCATED NEAR THE VIRGIN ISLANDS. THE LOW IS
EXPECTED TO CONTINUE MOVING ON A GENERAL WSW OR W TRACK AND
TROPICAL CYCLONE FORMATION...IF ANY...IS NOT EXPECTED TO OCCUR
UNTIL THE SYSTEM REACHES THE WESTERN CARIBBEAN SEA IN ABOUT TWO
DAYS. SHOWERS AND SQUALLS ARE EXPECTED TO CONTINUE OVER PORTIONS
OF THE VIRGIN ISLANDS...PUERTO RICO...AND HISPANIOLA.
NHC 2:05
A COUPLE OF LOW PRES AREAS ARE ANALYZED IN THE REGION THIS
AFTERNOON. IN THE E CARIB...A WSW MOVING LOW IS CENTERED TO THE
SW OF PUERTO RICO NEAR 17N68W...ANALYZED 1006 MB. THIS LOW HAS
NOT BECOME ANY BETTER ORGANIZED TODAY AS THE LOW-LEVEL
CIRCULATION IS WELL EXPOSED W OF THE DENSE CLOUDINESS. THE MOST
ACTIVE AREA OF CONVECTION IS FAR TO THE E OVER THE LESSER
ANTILLES FROM 13N-18N E OF 64W. THIS PRECIP IS BEING ENHANCED BY
A SMALL UPPER LOW LOCATED NEAR THE VIRGIN ISLANDS. THE LOW IS
EXPECTED TO CONTINUE MOVING ON A GENERAL WSW OR W TRACK AND
TROPICAL CYCLONE FORMATION...IF ANY...IS NOT EXPECTED TO OCCUR
UNTIL THE SYSTEM REACHES THE WESTERN CARIBBEAN SEA IN ABOUT TWO
DAYS. SHOWERS AND SQUALLS ARE EXPECTED TO CONTINUE OVER PORTIONS
OF THE VIRGIN ISLANDS...PUERTO RICO...AND HISPANIOLA.
interesting,everyone has been watching the circulation sw of hispaniola,and then I saw the small circulation east of PR.
could the so cuba blob be 91l latter on today its been sittiing there for 12 hours now
Don't think so, Pressure is not falling and no Surface Low that i can see, just a Upper to Mid level Spin.
From what has been said the Spin E. of Pr. is the ULL that 90L got reid of.
interesting,everyone has been watching the circulation sw of hispaniola,and then I saw the small circulation east of PR.
From what has been said the Spin E. of Pr. is the ULL that 92L got reid of.
92L,now you've confused me Tampa
Pressures falling a little 29.83 nearby Ship & Buoy
if the cmc is correct,southern florida would just get grazed.
I don't see that happening as the High appears to be building and planted in place not allowing for such a turn..IMO
181. NEwxguy 6:18 PM GMT on October 26, 2007
if the cmc is correct,southern florida would just get grazed.
I don't see that happening as the High appears to be building and planted in place not allowing for such a turn..IMO
Yeh,I agree,models are kind of split on where that high is suppose to build and how strong.
Look at the 24 hour pressure...for the Cuba blob--
The pressure now is 1012.0mb yesterday the same time it was 1010.1mb lower yesterday than it is today....im talking about the Cuba blob
Tampa the pressure with 90L is 1004 today, not 1012
That pressure is not for 90L. That pressure 1012 is for the thing near Cuba
Slow blog with a possible Hurricane coming.......backed up by Floodman and Patrap's boxes
OMG...he said "boxes"
Thank you G35 Wayne for the inconsistent updates
LOL!
It does appear 90L is actually starting to get its act together a little better. What do you think.
How many times we have to tell ya don't say the "B" word......lol
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