Hurricane Jimena, California smoke, and Invest 94L

By: Dr. Jeff Masters , 14:10 GMT 1. Září 2009

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The most powerful hurricane on the planet so far this year, Hurricane Jimena, continues to maintain an intensity just below Category 5 strength. Jimena's 155 mph winds beat out the South Pacific's Tropical Cyclone Hamish (150 mph winds) as the most powerful tropical cyclone so far this year. Satellite estimates of Jimena's strength continue to show no weakening of the hurricane, and the Hurricane Hunters are currently enroute to Jimena to see exactly how strong the hurricane is.

Jimena is expected to make landfall Wednesday along the Mexico's Baja Peninsula. The hurricane is in an environment with low wind shear, 5 - 10 knots, and warm Sea Surface Temperatures (SSTs), 29°C. Shear is expected to remain low, and SSTs will decline to 28°C with a decrease in total oceanic heat content between now and landfall, and these conditions should allow Jimena to be a Category 3 or 4 hurricane at landfall. The computer models remain in good agreement that Jimena will miss the southern Baja resort town of Cabo San Lucas, and make landfall midway up the Baja Peninsula. However, just a small deviation in track would bring Jimena ashore in southern Baja. Cabo San Lucas has a 13% chance of receiving hurricane force winds, according to NHC's wind probability product. Serious flooding due to heavy rains will occur across all of the southern Baja today and Wednesday. Jimena is of similar intensity and is following a similar track to Hurricane Juliette of 2001, which brought 17.7" of rain to Cabo San Lucas. Juliette weakened to a 45 mph tropical storm before hitting Baja, but the storm killed 7 people and caused $20 million in damage to Mexico, mostly due to flash flooding and mudslides from the heavy rains. Jimena will probably be one of the strongest hurricanes ever to hit Baja.

After Jimena makes initial landfall on Baja, it will cross over the Gulf of California and make landfall on Mainland Mexico. Depending upon how up along the coast this second landfall occurs, Arizona may receive moisture from Jimena late this week that will be capable of causing flooding rains.


Figure 1. Rainfall totals from Hurricane Juliette of 2001, which had a similar track and intensity as Hurricane Jimena. Image credit: NOAA.

California fires creating major air pollution event
The wildfires burning east of Los Angeles, California have created a major air pollution event, and will continue to impact air quality for millions of people in Southern California today. The fires have burned over 90,000 acres and have led to Unhealthy to Hazardous Air Quality Index (AQI) levels (Code Red to Code Brown) for the past five days in nearby regions. Not only are fine smoke particles directly elevating the most deadly form of air pollution--particle pollution, the gases in the smoke are reacting with sunlight to form ground-level ozone, another dangerous pollutant. High pressure over the southwestern states today will keep temperatures hot and relative humidity low in the vicinity of the fires. Smoke has settled into the valleys of Los Angeles County overnight and in the eastern San Bernardino Valley. While onshore ocean breezes Tuesday afternoon are expected to move smoke into the mountains, winds will also increase fire growth potential. Air pollution levels will continue to reach the Unhealthy level (code red, see Figure 2) today over much of the Los Angeles area. By Wednesday, weather conditions will improve as the high pressure region over Southern California weakens and moves east, bringing cooler temperatures, higher humidity, and stronger airflow from the cool ocean, aiding firefighting efforts.

Health tip: People in areas directly impacted by smoke should avoid any vigorous exertion, indoors or outdoors. In addition, people with respiratory or heart disease, the elderly, and children should remain indoors. Individuals without air conditioning who stay inside with the windows closed may be in danger during extremely hot weather. In these cases, individuals should seek alternative shelter. For the latest information on this air pollution event, see the latest South Coast Air Quality Management District Air Quality Advisory.

Check out our wundermap for Los Angeles with the fire layer turned on to see where the fire and smoke are located, and track the temperatures and winds during today's air pollution event.


Figure 2. NASA MODIS satellite image of the California fires of August 31, 2009 (top) with air pollution levels at major cities superimposed. Bottom: air quality forecast for today, September 1, 2009. Image credit: EPA AIRNOW.

Invest 94L strong but disorganized
Tropical wave 94L, about 250 miles east of the Lesser Antilles Islands, continues to toy with the idea of becoming a tropical depression. Infrared satellite imagery shows the low has developed a region of heavy thunderstorms that extend high into the atmosphere. This morning's QuikSCAT pass showed surface winds of 45 mph beneath these thunderstorms. However, QuikSCAT showed no surface circulation, with a large and rather confused region of wind shifts and lines of convergence at the surface. Recent satellite wind shear analyses by NOAA/Colorado State University and the University of Wisconsin show that wind shear has oscillated between 10 - 20 knots over 94L this morning, and this shear is keeping the storm disorganized. Also, last night's upper-air balloon sounding from Guadeloupe is showing the presence of a narrow jet of 30 knot winds from the east at 700 mb (3000 meters). The relatively crude measures of shear we use, taking the difference between the wind at 200 mb and 850 mb, will miss seeing these sort of this layers of shearing winds that can have a strong negative impact on the organization of a developing tropical disturbance. It is apparent from visible satellite imagery that shear is causing some disruption to the southwest side of 94L, and that there is no surface circulation. The storm also has fewer low-level spiral bands than yesterday.

The forecast for 94L
The latest of 00Z and 06Z model runs continue to be split on whether 94L will develop or not, with the GFDL and HWRF models bringing 94L to hurricane strength in 4 days, and the NOGAPS and ECMWF predicting 94L will just be a disturbance 4 days from now. SSTs will be warm, in the 28 - 29°C range, and dry air should have only a minor inhibiting effect, but high shear may continue to delay 94L from developing into a tropical depression for several days. The storm is moving more slowly today, about 10 mph, and will be steered west-northwest to northwest over the next three days thanks to the presence to two upper-level lows to the northwest of the storm. The degree of northward motion of 94L will depend upon how soon the storm becomes a tropical depression and begins intensification. If 94L follows the GFDL and HWRF model's predictions, and intensifies into a hurricane four days from now, a more northwestward track taking the storm between the Lesser Antilles and Bermuda is likely. If 94L lingers a few more days as a tropical disturbance, a more southerly track over the northern Lesser Antilles Islands, Puerto Rico, and the Bahamas is more likely.

The Hurricane Hunters will investigate 94L at 2 pm this afternoon, and I'll update the blog by 3:30 pm.

Jeff Masters

Station Fire with Plane (jrkerns)
Station Fire burning to the North of Los Angeles, as seen from a hilltop in Reseda. The DC-10 firefighting plane can bee seen turning in towards the fire.
Station Fire with Plane
Red Sky In The Morning . . . (wb6ypf)
Morning view of the East Flank of the Station Fire from my Back yard. Weather Conditions as of 6am, Temperature 74°, 13% Humidity and slight wind from the Northeast. Forecast is for triple digit Temperatures again today. Check my WeatherCam for current images throughout the day. http://www.westphalfamily.com/wxdata2.html Here's hoping for a quiet day.
Red Sky In The Morning . . .
Smoke over LA continues (PeteShackle)
On August 30th, 2009, smoke plumes continue to rise to 10,000 feet over LA from the fires in the surrounding mountains. The city is now almost concealed in the smoke at bottom center. Picture taken from Palos Verdes.
Smoke over LA continues

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1233. juniort
03:49 GMT 2. Září 2009
hello everyone, is it my imagination or has Erika drifted southward, or is it expanding it area of convection?
Member Since: 19-07-09 Posts: 0 Comments: 69
1232. guygee
20:53 GMT 1. Září 2009
Quoting kitkat954:


Has this already curved? If not, then its a "curve", not a "recurve".


How about this:

Not Curving: Embedded in the Easterlies
Curving: Turning north around the subtropical high.
Recurving: Embedded in the Westerlies.
UnRecurving: Left behind by the trough and being driven W/SW by the building high.
ReReCurving: Being picked up by the next trough.
ReverseCurving: Running into South America.

I love this place!
Member Since: 16-09-05 Posts: 0 Comments: 3200
1231. StormFreakyisher
20:10 GMT 1. Září 2009
Quoting Chiggy007:
Look at that fantastic wave with massive spin over Africa around 5W...looks better thna it was 6 hours ago..
Should be exiting Africa next day or so...

anybody like to comment on that one if you care to take a break from 94L :)

Me, I am bored already of 94L.I always say this "If your going to form, form already but if your going to die just dissipate already."
Member Since: 16-05-09 Posts: 0 Comments: 684
1230. StormFreakyisher
20:08 GMT 1. Září 2009
Quoting justalurker:
why do people still compare latest storms to past storms? what is the chance of having the same atmosphere conditions as it did 50 years ago..I never understood that..I never see max mayfield ever mention.."we are basing the track on hurricane of 1886"

It's called climatology, such as the Herbert Box.
Member Since: 16-05-09 Posts: 0 Comments: 684
1229. Greyelf
20:07 GMT 1. Září 2009
.
Member Since: 05-06-07 Posts: 18 Comments: 838
1228. quakeman55
20:04 GMT 1. Září 2009
Quoting hurricane23:


Changed? You dont even know me. Alright be back later gonna get some water at publix.

You haven't changed one bit; you've always been very informative.
Member Since: 31-03-02 Posts: 1 Comments: 1276
1227. Chiggy007
20:03 GMT 1. Září 2009
Look at that fantastic wave with massive spin over Africa around 5W...looks better thna it was 6 hours ago..
Should be exiting Africa next day or so...

anybody like to comment on that one if you care to take a break from 94L :)
1226. slavp
19:58 GMT 1. Září 2009
Quoting nrtiwlnvragn:
Marine Weather Discussion


LOW PRES CENTERED OVER THE TROPICAL ATLC
ZONE IS FORECAST TO CROSS 65W LATE FRI AND TRACK ACROSS THE
BAHAMAS SAT AND SUN. AS MENTIONED IN PREVIOUS DISCUSSION THE
GFS IS THE LEAST AGGRESSIVE WITH THIS FEATURE. HOWEVER THE LOW
DOES HAVE THE POTENTIAL TO BECOME A TROPICAL CYCLONE.

SURFACE 1007 MB LOW PRES IS CENTERED NEAR 16N57W MOVING NW. THE
LOW COULD DEVELOP INTO A TROPICAL CYCLONE WITHIN THE NEXT 48
HOURS. THE STRONGEST WINDS WITH THE LOW ARE OVER THE N SEMICIRCLE
WITH A TIGHTENED PRES GRADIENT BETWEEN THE LOW AND HIGHER PRES TO
THE N. THE LOW SHOULD MOVE JUST TO THE N OF THE LESSER ANTILLES
AND MOVE W OF THE AREA BY FRI. A LARGE CLUSTER OF STRONG
CONVECTION IS JUST E OF THE LOW LEVEL CENTER. OTHERWISE 15-20 KT
WINDS OVER THE S CENTRAL CARIBBEAN...AND 5-10 KT WINDS OVER THE
NW CARIBBEAN.
Do they expect it to travel that far west that they mention the shear in the NW Carribean?
1225. justalurker
19:57 GMT 1. Září 2009
why do people still compare latest storms to past storms? what is the chance of having the same atmosphere conditions as it did 50 years ago..I never understood that..I never see max mayfield ever mention.."we are basing the track on hurricane of 1886"
Member Since: 18-08-09 Posts: 0 Comments: 157
1222. chucky7777
19:53 GMT 1. Září 2009
Quoting JupiterFL:


At least when school lets out we get Futuremet and Drak. Thanks to the both of you for being great bloggers and amateur weathermen.
Yes keep up the good work....
Member Since: 19-10-05 Posts: 0 Comments: 174
1221. futurenavymet
19:53 GMT 1. Září 2009
Quoting hurricane23:



Ah! Sorry cane not this season. Just to many damn trofs.
you must be a crow eater 23. you havent been in here all day like the rest us and you come in here and be like well she isnt doing this or that. know the facts first bro or get ya plate ready. i dont see anymore troughs.
1220. IKE
19:53 GMT 1. Září 2009
Quoting hurricane23:
The 12z GFS has a thunderstorm moving through the bahamas.


LOL!
Member Since: 09-06-05 Posts: 23 Comments: 37860
1219. canesrule1
19:53 GMT 1. Září 2009
Quoting Stormchaser2007:


Looks somewhat similar to Danny.

Large elongated center to the west of the convection.
u r not on my ignore list, i took u off, but if u continue to be an a** you will be on my ignore list.
1218. aspectre
19:53 GMT 1. Září 2009
self-deleted to place on the next blot
Member Since: 21-08-07 Posts: 0 Comments: 4860
1217. hurricane23
19:52 GMT 1. Září 2009
The 12z GFS has a thunderstorm moving through the bahamas.
Member Since: 14-05-06 Posts: 8 Comments: 13841
1216. conchygirl
19:52 GMT 1. Září 2009
NEW BLOG GANG!
Member Since: 11-06-08 Posts: 24 Comments: 5910
1214. chevycanes
19:52 GMT 1. Září 2009
Quoting btwntx08:
23 has changed alot don't trust him no more

because he doesn't say what you want to hear?

i don't know why people get all upset when people actually use facts to back up their statements instead of "gut feelings" and the like. it's quite funny.

Member Since: 06-08-07 Posts: 0 Comments: 693
1213. TexasHurricane
19:52 GMT 1. Září 2009
Quoting Stormchaser2007:


Shear...

A sheer is what you cut sheep with.


Ha Ha funny....so I mispelled....Can I please get an answer?
Member Since: 02-07-09 Posts: 0 Comments: 2811
1211. bluewaterblues
19:51 GMT 1. Září 2009
Futuremet

Good afternoon to you...I always appreciate your informative post!
Member Since: 06-08-06 Posts: 0 Comments: 164
1209. hurricane23
19:51 GMT 1. Září 2009
Quoting btwntx08:
23 has changed alot don't trust him no more


Changed? You dont even know me. Alright be back later gonna get some water at publix.
Member Since: 14-05-06 Posts: 8 Comments: 13841
1208. canesrule1
19:51 GMT 1. Září 2009
Quoting btwntx08:
23 has changed alot don't trust him no more
who happens to be "23"?
1207. Stormchaser2007
19:51 GMT 1. Září 2009
Quoting scla08:


Looks somewhat similar to Danny.

Large elongated center to the west of the convection.
Member Since: 09-06-07 Posts: 4 Comments: 15950
1205. CaneHunter031472
19:51 GMT 1. Září 2009
94L looks like it is struggling bad. I wonder for how long before it intensifies if it does.
Member Since: 01-08-07 Posts: 0 Comments: 202
1204. JupiterFL
19:50 GMT 1. Září 2009
Quoting futuremet:
Good afternoon folks:

This the trough that the ECMWF expects to lift invest 94L out, not the current trough. It is a slightly amplified longwave trough that is expected to emerge of the canadian eastern maritime seaboard by Tuesday.

12Z ECMWF Tuesday



12Z gfs




The GFS expects the trough to be a slightly weaker. If we analyze further, it becomes evident that it is all about that timing and the strength of this weak longwave trough. The GFS and the CMC expects this system to move faster west than the ECMWF, thus, dodging most of the weakness. On the other hand if the trough is inadequate, it would still miss it. Even if the GFS were to slow it down in the 12Z run, it would still not go out to sea, because the trough is too weak.


Let's just wait and see


At least when school lets out we get Futuremet and Drak. Thanks to the both of you for being great bloggers and amateur weathermen.
Member Since: 10-08-05 Posts: 0 Comments: 2146
1202. TheCaneWhisperer
19:50 GMT 1. Září 2009
Quoting hurricane23:


Ah! Sorry cane not this season. Just to many damn trofs.


I swear half of things I say go right over your head, lol.
1201. IKE
19:50 GMT 1. Září 2009
Quoting iluvjess:
"I looked up the word recurve on wordweb.

Here's the definition>>>"Curve or bend (something) back or down".....

That's what the ECMWF shows happening to 94L."

The ECMF shows a curve. Think about it like a a standard archery bow. An standard archery bow is curved, correct? Thats the shape the ECMF is showing. Now, if you were to bend the top end of the archery bow "down" (as defined above), towards the opposite end, now that my friend is defined as a recurve.



"Kerry Emanuel in the Center for Meteorology and Physical Oceanography at the Massachusetts Institute of Technology expands on the details of hurricane behavior:

"Hurricanes almost always form over ocean water warmer than about 80 degrees F. in a belt of generally east-to-west flow called the trade winds. They move westward with the trade winds and also drift slowly poleward. Eventually, if they last long enough, they will drift poleward far enough to enter the belt of westerly winds that prevails in middle latitudes. When this happens, the hurricanes 'recurve' toward the east and thereafter follow paths that are generally both eastward and poleward."....


From...Link

Google searched hurricanes that recurve and it found Results 1 - 10 of about 12,900 for hurricanes that recurve. (0.21 seconds)
Member Since: 09-06-05 Posts: 23 Comments: 37860
1200. Stormchaser2007
19:50 GMT 1. Září 2009
Quoting canesrule1:
ignore #28


Announcing your ignore list will get you banned.

Member Since: 09-06-07 Posts: 4 Comments: 15950
1199. scla08
19:49 GMT 1. Září 2009
Member Since: 24-07-06 Posts: 0 Comments: 272
1198. largeeyes
19:49 GMT 1. Září 2009
They didn't find a 50mph TS. They found a 60mph invest.
Member Since: 22-08-06 Posts: 0 Comments: 1462
1197. FloridaTigers
19:49 GMT 1. Září 2009
I don't get all this hampering on "west" and "hitting florida". Who has exactly said any of this in the last hour?
Member Since: 17-05-09 Posts: 0 Comments: 559
1195. Stormchaser2007
19:50 GMT 1. Září 2009
57 mph winds and no closed circulation.


What a weird year this has been.
Member Since: 09-06-07 Posts: 4 Comments: 15950
1194. canesrule1
19:48 GMT 1. Září 2009
Quoting palmbaywhoo:

arent you from miami? or was it north carolina? or another gulf state?
Miami
1193. nrtiwlnvragn
19:48 GMT 1. Září 2009
Marine Weather Discussion


LOW PRES CENTERED OVER THE TROPICAL ATLC
ZONE IS FORECAST TO CROSS 65W LATE FRI AND TRACK ACROSS THE
BAHAMAS SAT AND SUN. AS MENTIONED IN PREVIOUS DISCUSSION THE
GFS IS THE LEAST AGGRESSIVE WITH THIS FEATURE. HOWEVER THE LOW
DOES HAVE THE POTENTIAL TO BECOME A TROPICAL CYCLONE.

SURFACE 1007 MB LOW PRES IS CENTERED NEAR 16N57W MOVING NW. THE
LOW COULD DEVELOP INTO A TROPICAL CYCLONE WITHIN THE NEXT 48
HOURS. THE STRONGEST WINDS WITH THE LOW ARE OVER THE N SEMICIRCLE
WITH A TIGHTENED PRES GRADIENT BETWEEN THE LOW AND HIGHER PRES TO
THE N. THE LOW SHOULD MOVE JUST TO THE N OF THE LESSER ANTILLES
AND MOVE W OF THE AREA BY FRI. A LARGE CLUSTER OF STRONG
CONVECTION IS JUST E OF THE LOW LEVEL CENTER. OTHERWISE 15-20 KT
WINDS OVER THE S CENTRAL CARIBBEAN...AND 5-10 KT WINDS OVER THE
NW CARIBBEAN.
Member Since: 23-09-05 Posts: 15 Comments: 11343
1192. canesrule1
19:48 GMT 1. Září 2009
Quoting Stormchaser2007:


Lol

Didnt know you could get a Met degree in elementary school.
ignore #28
1191. Stormchaser2007
19:47 GMT 1. Září 2009
Quoting JupiterFL:


Hooked on Weather, worked for me!


LOL!
Member Since: 09-06-07 Posts: 4 Comments: 15950
1189. PensacolaDoug
19:47 GMT 1. Září 2009
"Recurve" it's a met thing....you wouldn't understand it...
Member Since: 25-07-06 Posts: 0 Comments: 662
1188. futuremet
19:47 GMT 1. Září 2009
Good afternoon folks:

This the trough that the ECMWF expects to lift invest 94L out, not the current trough. It is a slightly amplified longwave trough that is expected to emerge of the canadian eastern maritime seaboard by Tuesday.

12Z ECMWF Tuesday



12Z gfs




The GFS expects the trough to be a slightly weaker. If we analyze further, it becomes evident that it is all about that timing and the strength of this weak longwave trough. The GFS and the CMC expects this system to move faster west than the ECMWF, thus, dodging most of the weakness. On the other hand if the trough is inadequate, it would still miss it. Even if the GFS were to slow it down in the 12Z run, it would still not go out to sea, because the trough is too weak.


Let's just wait and see
Member Since: 19-07-08 Posts: 43 Comments: 4051
1187. canesrule1
19:47 GMT 1. Září 2009
Quoting btwntx08:
1161:he's kidding
I don't care. I don't want to see his posts.
1186. FLWeatherFreak91
19:47 GMT 1. Září 2009
TS Erika will be named at 5:00 est with winds of 50 mph heading WNW
Member Since: 01-12-06 Posts: 2 Comments: 3634
1184. palmbaywhoo
19:47 GMT 1. Září 2009
Quoting canesrule1:
According to this Florida and the rest of the Eastern U.S coast is in danger.

arent you from miami? or was it north carolina? or another gulf state?
Member Since: 18-08-08 Posts: 0 Comments: 394
1183. chevycanes
19:47 GMT 1. Září 2009
would a meteorologist ask this?

39. canesrule1 11:42 AM EDT on August 18, 2009
the lower the pressure of the high is the stronger it is or vice-versa?
Member Since: 06-08-07 Posts: 0 Comments: 693

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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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