Hurricane warnings for Baja; 94L forming spiral bands

By: Dr. Jeff Masters , 3:36 PM GMT on August 31, 2009

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Hurricane warnings are in effect for the southern tip of Mexico's Baja Peninsula, where powerful Hurricane Jimena is expected to make landfall Tuesday night or Wednesday morning. The hurricane is in an environment with low wind shear, 5 - 10 knots, and warm Sea Surface Temperatures (SSTs), 30°C. Shear is expected to remain low, and SSTs will decline to 28°C with a corresponding decrease in total oceanic heat content between now and landfall, and these conditions should mean that Jimena will be a Category 3 or 4 hurricane at landfall. Outer rain-bands of the hurricane will be appearing on Los Cabos radar soon, though the Mexican Weather Service web site has been hard to reach today. The computer models are split, with one camp calling for a landfall in southern Baja, and the other camp calling for landfall farther north near central Baja. The official NHC forecast splits the difference between these two solutions, and landfall could occur anywhere along a long stretch of the Baja coast. At this point, the UKMET model's solution taking Jimena westward out to sea is being discounted, since it is an outlier.

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. Image of Hurricane Jimena taken by NASA'a MODIS instrument at 2020 UTC Sunday, 8/30/09.

Invest 94L
The well-organized tropical wave (94L) near 14.5N, 52W, about 500 miles east of the central Lesser Antilles Islands, continues to be a threat to develop into a tropical depression. Visible satellite imagery and this morning's QuikSCAT pass do not show a surface circulation yet, though 94L does have a large envelope of moisture and some modest heavy thunderstorm activity. QuikSCAT noted winds up to 30 mph. Water vapor satellite loops show that 94L has moistened the region surrounding it considerably, and dry air from the Saharan Air Layer is not a major impediment to development. Wind shear is a low 5 - 10 knots, and the ocean temperature are a moderately warm 28°C. Visible satellite loops over the past two hours show low-level spiral bands developing on 94L's northeast side, and I give a 70% chance the Hurricane Hunters will find a tropical depression or tropical storm on Tuesday when they investigate 94L.


Figure 2. Morning satellite image of 94L, showing low-level spiral bands developing on the northeast side.

The center of 94L probably passed over Buoy 41040, located at 14.5N, 53W over the past hour. Winds blew northeasterly early this morning, then went calm, then shifted to southerly late this morning. The winds were less than 10 knots during the center passage, so the circulation of 94L is not yet well-defined. The pressure fell significantly as 94L moved over the buoy (seen only after one removes the wiggles due to daily atmospheric tide effect present in the tropics). 94L will appear on Martinique radar on Tuesday.

The forecast for 94L
Shear will remain low, 5 -10 knots, over the next 5 days, SSTs will be warm, in the 28 - 29°C range, and dry air should have only a minor inhibiting effect, so I can't see anything that will prevent 94L from developing into a tropical depression over the next 1 - 2 days. The HWRF model develops 94L into a hurricane 4 days from now, as does the SHIPS intensity model, but other models, such as the GFDL, ECMWF, and GFS, do not develop 94L at all.

Model solutions for the track of 94L are divergent. Water vapor satellite loops show two upper-level lows to the north and northwest of 94L that are pulling the storm to the west-northwest, and 94L's motion is expected to range between the west-northwest and northwest over the next three days. By Tuesday, 94L will slow down from its current 15 mph forward speed to about 10 mph. Most of the models predict that the steering influence of the upper-level lows will pull 94L far enough north that the storm will miss the Lesser Antilles, with a closest approach occurring Wednesday and Thursday. However, the ECMWF and HWRF models have 94L passing within 200 miles of the islands, and the northern Lesser Antilles may experience tropical storm conditions on Thursday.

At the longer ranges, the fate of 94L is highly uncertain. The Canadian model turns 94L to the north near Bermuda, then out to sea, while the NOGAPS model foresees a threat to the U.S. East Coast early next week. Both of these solutions are believable. The Hurricane Hunters are scheduled to make their first flight into 94L on Tuesday afternoon at 2pm EDT.

Elsewhere in the Atlantic
The remains of an old cold front are bringing cloudiness and showers to the northern Gulf of Mexico and waters offshore North and South Carolina. The GFS and NAM models indicate an area of low pressure may develop along this old front near the Florida Panhandle or off the coast of North Carolina by Thursday. However, such a low may be extratropical and not tropical.

My next post will be between 3 - 5pm this afternoon.

Jeff Masters

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1206. NHCaddict
6:00 PM GMT on September 28, 2010
Sorry for the newbie question, but how to you change barometric pressure from inches to mb? It's currently 29.68" at my house west of Orlando, but I'd like to know what it is in mb and be able to calculate that myself. TIA:)
Member Since: September 16, 2010 Posts: 0 Comments: 71
1205. jbryant
10:28 PM GMT on August 31, 2009
Quoting GatorWX:
I am changing my avatar image to the old school UF logo since there are now three or four users with identical avatars featuring the UF gator head. Anyone have any idea how to go about doing that? I had a heck of a time getting an image as my pic in the first place. Any ideas or clues would be greatly appreciated, TIA.

Why dont you ask the Doctor?
1204. popartpete
10:24 PM GMT on August 31, 2009
Quoting hurristat:
The tropics page says that Jimena has 155 mph winds. So does this mean that Jimena is a Cat 5 or a Cat 4?
156 is the first # of speed of a cat 5. 155 or greater. This is confusing.
Member Since: July 10, 2007 Posts: 0 Comments: 429
1203. hurristat
10:17 PM GMT on August 31, 2009
The tropics page says that Jimena has 155 mph winds. So does this mean that Jimena is a Cat 5 or a Cat 4?
Member Since: October 15, 2008 Posts: 11 Comments: 2312
1199. TriniGirl26
9:22 PM GMT on August 31, 2009
I'm confuse.stupid question: if Jimena is a possible CAT4/5, why will its force go down to a CAT1 or 2 when it makes landfall? why not stay as a CAT 4?
Member Since: August 18, 2009 Posts: 0 Comments: 201
1196. weathermancer
9:15 PM GMT on August 31, 2009
Could Kevin go Fujiwara around Jimena?

I know i know. I'm not an expert. The models for Kevin look like a giant spider... yet... it is a serious question.

Weatheromancer
hfx, ns, canada
Member Since: August 29, 2009 Posts: 12 Comments: 482
1195. KEHCharleston
9:14 PM GMT on August 31, 2009
Hello folks

HadesGodWyvern never did understand why 135 knots is not officially a Category 5
155 mph does seem catastrophic - Someone was asking about you earlier today. Was missing your updates. (I referred them to your blog)

GeorgefromLosCabos thanks for sharing will be checking back on your blog often

CycloneOz Thanks for bringing XtremeHurricanes to us. Stay safe

This is a bit north of the Jimena path, but here is a webcam at the at the K39 area located in Northern Baja, Mexico (about an hour south of San Diego)
Member Since: August 19, 2008 Posts: 6 Comments: 2490
1194. Fshhead
9:12 PM GMT on August 31, 2009
Quoting dolphingalrules:
the 5:oo is out..ITS LIKE A "ANDREW"



WOW! Man calm down some, your gonna scare people half to death with a comment like that.
The thing has not even formed yet. LOL
Member Since: November 19, 2005 Posts: 9 Comments: 9960
1193. usa777
9:12 PM GMT on August 31, 2009
JMHO But it looks to me like the west side of 94L is starting to feel the effects of the shear. You can clearly see the west side getting shredded. Once again JMHO.
Member Since: August 11, 2008 Posts: 0 Comments: 164
1192. cattlebaroness
9:11 PM GMT on August 31, 2009
Howdy yall. Does anyone know how populated Baja CA is. Have they suggested evacuation. No matter what happens with 94, it appears that Baja is in for some very severe weather and a very limited area to evacuate to without significant lead time.
1191. serialteg
9:10 PM GMT on August 31, 2009
Quoting chevycanes:
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?


hehe owned
Member Since: August 22, 2006 Posts: 2 Comments: 1983
1190. chevycanes
9:08 PM GMT on August 31, 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: August 6, 2007 Posts: 0 Comments: 693
1188. GatorWX
9:06 PM GMT on August 31, 2009
Every time I try to upload the image I want to use as my new avatar I get an error message: "Not submitting because no changes were made to the album." Anyone know what I am doing wrong?? I've added a few other images in the past and had no problems at all. I put the file I'm going to use in, didn't add any comments in the "special instructions" box and hit the "send all to photo approval queue" button and I just keep getting the error. What type of changes must I make? Please, if anyone could help I would truly appreciate it. Thankyou!
Member Since: January 1, 2008 Posts: 0 Comments: 3384
1187. hurricanehanna
9:06 PM GMT on August 31, 2009
Quoting Grothar:


What did Yogi Berra say, folks???

"Always go to other people's funerals otherwise they won't come to yours"
Member Since: September 5, 2007 Posts: 0 Comments: 3488
1184. gordydunnot
9:05 PM GMT on August 31, 2009
Visible of 94L looks the best I have seen since early am. The band the Doc pointed out earlier looks much more impressive on latest visible.
Member Since: August 18, 2008 Posts: 0 Comments: 3113
1183. JupiterFL
9:05 PM GMT on August 31, 2009
Quoting canesrule1:
stormno is on my ignore list and is a troll, so please do not quote him.


NO
Member Since: August 10, 2005 Posts: 0 Comments: 2146
1181. cdnbananabelt
9:04 PM GMT on August 31, 2009
Pressure dropping rapidly, and her winds are at 155.49 (yeah!) mph - cat 5, folks!
1180. nrtiwlnvragn
9:04 PM GMT on August 31, 2009
NEW BLOG
Member Since: September 23, 2005 Posts: 14 Comments: 11211
1179. louisianaboy444
9:06 PM GMT on August 31, 2009
It is called being retired, lol...and btw what i meant by the Bill thing coming towards Florida was based utterly on my gut feeling

Well Einstein knew 100 percent that the theory of Relativity was true but almost didn't prove it because he couldn't finialize the math and some other guy almost stole the idea from him...the idea is in science a gut feeling means nothing unless you have hard prove you have nothing...it is very dangerous to be a scientist and let your gut feeling play a role especially when they can potentially have panicked people to contend with
Member Since: August 29, 2006 Posts: 22 Comments: 1352
1178. SavannahStorm
9:04 PM GMT on August 31, 2009
Quoting Grothar:


What did Yogi Berra say, folks???


"This is like deja vu all over again."
Member Since: September 22, 2005 Posts: 18 Comments: 2343
1177. serialteg
9:03 PM GMT on August 31, 2009
Quoting canesrule1:
excuse me? Um have you not checked the 18z models?!?! all of them except 4 or 5 unreliable models have it curving to sea, and did you not notice that I wrote the percentages are based on the latest models not my opinion, why would you question my degree? huh?


No, I haven't checked the models. I don't trust them. To me anyone who tries to judge storms by the models can, and probably will, be set up for a surprise.

Actually whenever I see a post about models, I skip it. It's better when the thing is closer, but I use it "just for recreational purposes".

To me, basing where this TROPICAL WAVE is going to hit when it's thousands of miles from where you say it's going to hit is the reason I started my reply with FAIL.

So you ARE a Ph.D. Meteorologist? Hmm...
Member Since: August 22, 2006 Posts: 2 Comments: 1983
1176. Bordonaro
9:03 PM GMT on August 31, 2009
Quoting Grothar:


What did Yogi Berra say, folks???

I am not sure what he said, but, those 2 waves ready to come off of Africa look REAL MEAN!! I would not be suprised to see one or both of them become TD's!
Member Since: August 25, 2009 Posts: 20 Comments: 6785
1175. hondaguy
9:03 PM GMT on August 31, 2009
Quoting cdnbananabelt:
Link

According to the speed conversion, Jimena qualifies as a borderline cat 4/5 cane. She's not making landfall as a cat 1. Hope they're prepared.


They are already saying she will make landfall as a Cat 2 at least...maybe higher.
1174. mkmand
9:02 PM GMT on August 31, 2009
931 mb pressure with Jimena !!! Whao!!!
Member Since: August 30, 2008 Posts: 0 Comments: 47
1173. TreasureCoastFl
9:02 PM GMT on August 31, 2009
Quoting Grothar:


What did Yogi Berra say, folks???

"It's pretty far, but it don't seem like it" ?
Member Since: August 18, 2008 Posts: 0 Comments: 474
1172. TheCaneWhisperer
9:02 PM GMT on August 31, 2009
Quoting AllStar17:
This blog is hilarious. From "It looks impressive, and a TD is likely soon!" this morning, to now "the system is disorganized and being sheared, and is not likely to be TD anytime soon". Too funny how quickly this blog changes it's feelings.


They all want it to be the next cat five and STAT.

Now that work is done, I've actually had some time to look at everything and it doesn't look to bad, IMO. A little squashed and sheared, yes, core structure is improving though. If shear lets up tomorrow as forecast, 94L could be a biggie as the circulation is very large.
1171. canesrule1
9:02 PM GMT on August 31, 2009
Quoting JupiterFL:


If your going to use that comparison then I guess he is halfway finished with his degree.
stormno is on my ignore list and is a troll, so please do not quote him.
1170. Wariac
9:01 PM GMT on August 31, 2009
TD not TD....TD not TD..this blog can drive anyone crazy..LOL!!!!
Member Since: August 7, 2007 Posts: 0 Comments: 134
1169. Grothar
9:01 PM GMT on August 31, 2009
Quoting jipmg:


GFS turns it into a hurricane later on, but curves it out to sea


Good news!
Member Since: July 17, 2009 Posts: 71 Comments: 26460
1167. canesrule1
9:00 PM GMT on August 31, 2009
Quoting louisianaboy444:
I am in no mood, to fight.

Let me ask you something if you do have a PhD then why are you not working for a big oil company or corporation or a broadcast Meteorologist...and when it was clear that Bill was going no where near Florida you was still saying it was and giving percentages on it....any person with a PhD in weather would know better than that...not saying you dont have it but if you do you not using it to its full potential
It is called being retired, lol...and btw what i meant by the Bill thing coming towards Florida was based utterly on my gut feeling.
1166. cdnbananabelt
9:00 PM GMT on August 31, 2009
Quoting HadesGodWyvern:
National Hurricane Center
Tropical Cyclone Advisory #13
SEVERE TROPICAL CYCLONE JIMENA (EP132009)
21:00 PM UTC August 31 2009
=============================

SUBJECT: A Hurricane Warning Remains In Force

At 18:00 PM UTC, Hurricane Jimena (931 hPa) located at 18.5N 109.2W or 265 NM south of Cabo San Lucas, Mexico has sustained winds of 135 knots with gusts of 165 knots. The cyclone is reported as moving northwest at 9 knots.

Hurricane-Force Winds
======================
40 NM from the center

Gale/Storm-Force Winds
========================
120 NM from the center

Tropical Cyclone Warnings
==========================
A HURRICANE WARNING has been issued for southern portion of the Baja California Peninsula from Bahaia Magdalena southward on the west coast..and from San Evaristo southward on the east coast

Tropical Cyclone Watches
========================
A HURRICANE WATCH has been issued for Baja California north of Bahia Magdelena on the west coast to Punta Abreojos and north of San Evaristo to Mulege on the east coast

Forecast and Intensity
=====================
12 HRS: 19.6N 110.1W - 130 kts (SSHS-4 Cyclone)
24 HRS: 21.6N 111.1W - 125 kts (SSHS-4 Cyclone)
48 HRS: 25.5N 112.2W - 85 kts (SSHS-2 Cyclone)
72 HRS: 27.8N 112.7W - 50 kts (Overland TS)

---
never did understand why 135 knots is not officially a Category 5
Link

According to the speed conversion, Jimena qualifies as a borderline cat 4/5 cane. She's not making landfall as a cat 1. Hope they're prepared.
1165. hondaguy
8:59 PM GMT on August 31, 2009
Quoting CycloneOz:
A major outer band is coming in...

gots to go work!

later...


Have fun out there, and be careful!
1163. GatorWX
8:59 PM GMT on August 31, 2009
I am changing my avatar image to the old school UF logo since there are now three or four users with identical avatars featuring the UF gator head. Anyone have any idea how to go about doing that? I had a heck of a time getting an image as my pic in the first place. Any ideas or clues would be greatly appreciated, TIA.
Member Since: January 1, 2008 Posts: 0 Comments: 3384
1162. jipmg
8:59 PM GMT on August 31, 2009
Quoting Grothar:


What did Yogi Berra say, folks???


GFS turns it into a hurricane later on, but curves it out to sea
1160. JupiterFL
8:58 PM GMT on August 31, 2009
Quoting stormno:
canesrule if you have a degree in meteorology obama is white lmmfoa..


If your going to use that comparison then I guess he is halfway finished with his degree.
Member Since: August 10, 2005 Posts: 0 Comments: 2146
1159. CycloneOz
8:58 PM GMT on August 31, 2009
A major outer band is coming in...

gots to go work!

later...
Member Since: August 26, 2006 Posts: 10 Comments: 3751
1158. canesrule1
8:58 PM GMT on August 31, 2009
On Wednesday we will who will have to put up the shutters, lol.
1157. Chavalito
8:58 PM GMT on August 31, 2009
Quoting palmasdelrio:
Forgot to put the source of the bulletin. It's the NWS in San Juan. Do you think they're jumping the gun a little bit?
Of course they do.
Member Since: August 14, 2009 Posts: 0 Comments: 45
1156. AllStar17
8:58 PM GMT on August 31, 2009
This blog is hilarious. From "It looks impressive, and a TD is likely soon!" this morning, to now "the system is disorganized and being sheared, and is not likely to be TD anytime soon". Too funny how quickly this blog changes it's feelings.
Member Since: June 29, 2009 Posts: 13 Comments: 5313

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About

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