California fires and global warming; 90L lashes Puerto Rico

By: Dr. Jeff Masters , 2:38 PM GMT on October 26, 2007

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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

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1046. ShenValleyFlyFish
1:29 PM GMT on October 27, 2007
Rain may be over. Stepped outside to get the mail and there is enough blue in the sky to outfit all of Her Majesty's Royal Navy in pantaloons. We got 4.50in/114.3mm out of the system, probably more than last several months combined.
Member Since: September 9, 2007 Posts: 36 Comments: 4687
1045. ShenValleyFlyFish
1:08 PM GMT on October 27, 2007
1011. UYA 8:09 AM EDT on October 27, 2007
But hey! I could win the Lotto and the Canadian could be right! LMAO!


Saw a bumper sticker just about got me run over in a parking lot because i was ROAL. Said: The lotto A tax on poor people who can't do math.

BTW why don't you tone it down a little UYA. I consider you an asset and more folks who don't get your humor are waking up. I'd hate to see you get booted. A contrarian viewpoint can be useful as long as things don't get personal.
Member Since: September 9, 2007 Posts: 36 Comments: 4687
1044. ShenValleyFlyFish
12:51 PM GMT on October 27, 2007
Good morning all
Member Since: September 9, 2007 Posts: 36 Comments: 4687
1042. Chicklit
12:37 PM GMT on October 27, 2007
What is that thing off the west coast of Florida and what will it do? Where will it go?
Member Since: July 11, 2006 Posts: 14 Comments: 11408
1041. IKE
12:33 PM GMT on October 27, 2007
NEW BLOG!
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1040. IKE
12:31 PM GMT on October 27, 2007
BajaALemt 7:27 AM CDT on October 27, 2007
Same here, Ike. Love the sound of my windchimes in the morning :))


It beats the heat and humidity....


50.2 °F
Clear
Humidity: 85%
Dew Point: 46 °F
Wind: 3.0 mph from the North
Wind Gust: 12.0 mph
Pressure: 30.19 in (Rising)
Visibility: 10.0 miles
UV: 0 out of 16
Clouds: Clear -
(Above Ground Level)


The pressure has really been rising.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1039. UYA
12:28 PM GMT on October 27, 2007
It's not hard to forecast anything if you actually know where it is Storm! LMAO!
I have blind hogs that can do that.
1038. BajaALemt
12:27 PM GMT on October 27, 2007
Same here, Ike. Love the sound of my windchimes in the morning :))
Member Since: September 25, 2007 Posts: 53 Comments: 8533
1037. extreme236
12:27 PM GMT on October 27, 2007
So based upon what Im seeing in IR imagery convection is close to the center but has yet to really organize around and over it
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1036. IKE
12:27 PM GMT on October 27, 2007
Accuweather..........

"Watching the Caribbean for Possible Development

We continue to closely monitor two areas of low pressure in the Caribbean. A surface low that was just south of Jamaica on Thursday has moved northwest. As of Saturday morning the feature is just northeast of Honduras. This low has a pressure of about 1005 millibars and is expected to move very little through the weekend. Any development of this system will be slow to occur due to light shear. The steering flow over the northwestern Caribbean is weak and the shear will continue to diminish over the next two to three days. So, tropical development is possible early next week. Another surface low that yesterday was just north of the Virgin islands and northeast of Puerto Rico moved southwest as expected. The system moved right over Puerto Rico Friday morning and as of Friday evening is southwest of Puerto Rico. Satellite images show a well defined swirl in the clouds meaning there is some organization to the system. The surface pressure of this low has been holding right around 1005 millibars. This also suggests this system has a well developed lower-level structure. This low will move west-southwest toward the central Caribbean over the weekend. Any development of this low will also be very slow to occur.

Looking at this situation in the Caribbean, it would be unusual to have two lows form into separate organized tropical systems early next week. So, it's more probable that one of these lows will become more dominate and become the main feature to watch. The low southwest of Puerto Rico seems to look better organized at this time, but the low northeast of Honduras is in a better location for development. Our best guess is that we will see both lows come together and that will turn out to be the developing system that most global computer models are showing occurring in the northern Caribbean around Tuesday and Wednesday of next week."
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1035. extreme236
12:26 PM GMT on October 27, 2007
dvorak has the center at 70.4W/14.9N
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1034. extreme236
12:26 PM GMT on October 27, 2007
T1.0/1.0 90L -- Atlantic Ocean
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1032. extreme236
12:26 PM GMT on October 27, 2007
Im not saying the Ngps is right lol, I was just pointing out what it said.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1031. InTheCone
12:25 PM GMT on October 27, 2007
Thanks - I look forward to reading it!
Member Since: September 1, 2007 Posts: 0 Comments: 1990
1029. UYA
12:23 PM GMT on October 27, 2007
Well extreme....see how wrong the shear charts are.
1027. InTheCone
12:23 PM GMT on October 27, 2007
Good morning StormW!

Are you doing a synopsis today?
Member Since: September 1, 2007 Posts: 0 Comments: 1990
1026. BajaALemt
12:22 PM GMT on October 27, 2007
Mornin gamma
Member Since: September 25, 2007 Posts: 53 Comments: 8533
1025. seflagamma
12:22 PM GMT on October 27, 2007
StormW,

Good to see you here... will come back and read your thoughts on this when I return!
Member Since: August 29, 2005 Posts: 301 Comments: 40944
1024. IKE
12:21 PM GMT on October 27, 2007
BajaALemt 7:18 AM CDT on October 27, 2007
Morning folks.

Ike, I opened at 6am yesterday...The moon was SO bright toward the NW...and Venus was also REALLY bright in the SE


I noticed the water temps at the buoy 22 NM SSE of Biloxi are at 73 degrees. Barometer is up to 30.20! That combined with the developing Caribbean low will bring stiff winds to the gulf coast for a few days.

Yeah..it's nice out. There's a chance of rain where I live starting the middle of the week.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1023. extreme236
12:21 PM GMT on October 27, 2007
Actually, the NGPS shear run actually shows the anticyclone from the SW caribbean moving northward to near where 90L will be, not over 90L but near it
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1022. seflagamma
12:21 PM GMT on October 27, 2007
Good morning!

WHAT!!! those models do not look too good right now; I sure hope that system doesn't develope if it is suppose to follow some of those model's tracks.


will be lurking and checking in and out during the day as I can.

Please keep us updated on this thing.

Those of you off work; Enjoy Your Saturday!!!
Member Since: August 29, 2005 Posts: 301 Comments: 40944
1020. BajaALemt
12:20 PM GMT on October 27, 2007
Mornin' Storm!
Member Since: September 25, 2007 Posts: 53 Comments: 8533
1018. UYA
12:18 PM GMT on October 27, 2007
Sunday maybe....and forget the anticyclone for 90L.
That won't happen. At least not the current one in the extreme SW Carib corner.
1017. BajaALemt
12:18 PM GMT on October 27, 2007
Morning folks.

Ike, I opened at 6am yesterday...The moon was SO bright toward the NW...and Venus was also REALLY bright in the SE
Member Since: September 25, 2007 Posts: 53 Comments: 8533
1016. TampaSpin
12:15 PM GMT on October 27, 2007
Drak,
Good morning, you haven't said anything that has triggered off sounds affects jumping thru the blog again have ya....lol
Member Since: September 2, 2007 Posts: 179 Comments: 20448
1015. extreme236
12:13 PM GMT on October 27, 2007
Later today it should really start to move into the lower shear, so thats why I believe today will be its organization day.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1014. IKE
12:13 PM GMT on October 27, 2007
And....what a beautiful full moon setting this morning under clear skies...some winds...low of 50.4 at my house...wind chill in the 40's.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1013. Drakoen
12:11 PM GMT on October 27, 2007
1002. Smyrick145 12:01 PM GMT on October 27, 2007

Drakoen,
Are you concerned about the future intensity and path of 90L? I know many have asked you this but for some reason I have a bad feeling about this one because it seems it is getting its act together unlike so many other invests this year. What makes me so interested is the amount of fight 90L had in high wind shear and now that it will be in low wind, I can only imagine what 90L can do.


With high water temperatures ahead and low wind shear by an upper level high the system could develop significantly in the Caribbean. A tropical storm or hurricane cannot be ruled out, as Jeff Masters said.
Member Since: October 28, 2006 Posts: 57 Comments: 30717
1012. IKE
12:11 PM GMT on October 27, 2007
Here's what the NHC says....

"For the North Atlantic...Caribbean Sea and the Gulf of Mexico...

The broad area of low pressure over the eastern Caribbean Sea is now
centered about 175 miles south of Santo Domingo in the Dominican
Republic. The associated shower activity remains disorganized and
upper-level winds are currently not favorable for development. The
low is expected to move generally westward and tropical cyclone
formation...if any...is not expected until the system reaches the
western Caribbean Sea in a day or two. Showers and squalls are
expected to continue today over portions the Virgin Islands...Puerto
Rico...and Hispaniola."......

My guess...it's a TD by Monday.

The new coordinates place the system slightly further SE of it's earlier points...appears near the area of building convection.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1011. UYA
12:09 PM GMT on October 27, 2007
But hey! I could win the Lotto and the Canadian could be right! LMAO!
1010. IKE
12:08 PM GMT on October 27, 2007
Buoy out in the central Caribbean near 15N, 67.3W...

" S ( 170 deg true )
5-day plot - Wind Speed Wind Speed (WSPD): 13.6 kts
5-day plot - Wind Gust Wind Gust (GST): 21.4 kts
5-day plot - Wave Height Wave Height (WVHT): 3.6 ft
5-day plot - Dominant Wave Period Dominant Wave Period (DPD): 4 sec
5-day plot - Average Period Average Period (APD): 4.3 sec
5-day plot - Atmospheric Pressure Atmospheric Pressure (PRES): 29.78 in
5-day plot - Pressure Tendency Pressure Tendency (PTDY): +0.07 in ( Rising )

5-day plot - Air Temperature Air Temperature (ATMP): 79.7 °F
5-day plot - Water Temperature Water Temperature (WTMP): 83.5 °F
5-day plot - Dew Point Dew Point (DEWP): 74.7 °F
5-day plot - Heat Index Heat Index (HEAT): 84.2 °F"..........


The low(16.1N, 68.4W), is moving away from that buoy...seems logical the pressure would be rising...plus, winds are from the south.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1009. UYA
12:06 PM GMT on October 27, 2007
I had a nice chat a couple hours ago with a "friend" in Homestead.......
1008. extreme236
12:06 PM GMT on October 27, 2007
Well if you observed the wave that became melissa 12 hours before she formed you and I probably would have said the same thing, but 12 hours later she was a TD....two totally different systems though
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1007. UYA
12:04 PM GMT on October 27, 2007
Maybe one wont but where did you read that at?

It is called an observation. Don't have to read it anywhere.
1006. extreme236
12:03 PM GMT on October 27, 2007
Sunday looks to be the best day for it to form as today IMO will probably be its organization day
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1005. amazinwxman
12:03 PM GMT on October 27, 2007
and it's final on the no TD because UYA is the REAL Hurricane Authority(he's in the midst of a lawsuit against TWC for stealing it from him).
1004. extreme236
12:02 PM GMT on October 27, 2007
1003. UYA 12:01 PM GMT on October 27, 2007
No TD is forming in the Atlantic Basin this morning or today.......have a nice breakfast.


Maybe one wont but where did you read that at?
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1003. UYA
12:01 PM GMT on October 27, 2007
No TD is forming in the Atlantic Basin this morning or today.......have a nice breakfast.
1002. Smyrick145
12:01 PM GMT on October 27, 2007
Drakoen,
Are you concerned about the future intensity and path of 90L? I know many have asked you this but for some reason I have a bad feeling about this one because it seems it is getting its act together unlike so many other invests this year. What makes me so interested is the amount of fight 90L had in high wind shear and now that it will be in low wind, I can only imagine what 90L can do.
Member Since: September 30, 2006 Posts: 0 Comments: 14
1001. InTheCone
11:59 AM GMT on October 27, 2007
Morning All -

Thanks Drak., I just choked on my java :(
Member Since: September 1, 2007 Posts: 0 Comments: 1990
1000. UYA
11:59 AM GMT on October 27, 2007
Actually in Puerto Rico there are two deaths from a mudslide that ocurred in the central mountains last thursday. Two men died, they were brothers.



That's so terrible Refill.

999. extreme236
11:58 AM GMT on October 27, 2007
Good morning all! 90L looks better this morning as indicated in the dvorak number increase from too weak to 1.0
Member Since: August 2, 2007 Posts: 19 Comments: 19234
998. Drakoen
11:51 AM GMT on October 27, 2007
90L is getting better organized. Tropical depression appears to be forming.
Member Since: October 28, 2006 Posts: 57 Comments: 30717
997. refill
11:47 AM GMT on October 27, 2007
Actually in Puerto Rico there are two deaths from a mudslide that ocurred in the central mountains last thursday. Two men died, they were brothers.

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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