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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256. JLPR
Quoting palmasdelrio:

How is it that most of the models have 94L passing well to the north of the Leewards and PR, while the surface map you show here predicts it passing to the south of PR??


no one knows where it will go
we have to wait for a defined LLC to form
Member Since: September 4, 2007 Posts: 36 Comments: 5223
Quoting NoNamePub:
Hey All -
With Conditions looking good for intensification and organization - what is everyone's "guess" on how soon we see Erika?


I'm guessing when the NHC says we do.
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94L is moving to the Northwest.
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253. JLPR
Quoting Weather456:
No close low mean not much faith should be put into the models at this time.


exactly
Member Since: September 4, 2007 Posts: 36 Comments: 5223
Quoting TheCaneWhisperer:
This wouldn't be good.


How is it that most of the models have 94L passing well to the north of the Leewards and PR, while the surface map you show here predicts it passing to the south of PR??
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Quoting kmanislander:


Well, your take was correct. 94L is a tricky one. Looked like a TD from this morning but was still a wave then.

I am now seeing what looks like a surface low trying to consolidate right on 15N 52W but want to see another 4 frames to determine if that is so.

It doesn't seem to be going anywhere in a hurry though. Lots of action in the mid levels in the NE quad of the overall envelope.


I agree 100% Kman,..94L a Large CV TD to be soon,is going to be a Barn Burner I feel as I look downstream in time.

Best to watch this one closely.
Member Since: July 3, 2005 Posts: 426 Comments: 129093
Quoting IKE:
Some models have it heading north eventually. Some have it going west. Some have it going WNW. Latest NOGAPS has it off of the east central Florida coast at 192 hours.

These models are wearing and tearing on me.......


Maybe you need a vacation to Disney :)
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No close low mean not much faith should be put into the models at this time.
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Quoting palmbaywhoo:
ike do you mind posting the nogaps link please?


Nogaps 12z even more models here
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246. JRRP
me voy para la universidad
los leere despues
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Will be back later
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I think 94L wont't affect in Puerto Rico. The model consensus sustain that. So we are blessed once more.
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Quoting TreasureCoastFl:

It's way too early to tell where it will end up in over 5 days, IMO.
Everywhere from Texas up the east coast of US should watch for now because we all have seen how unpredictable a storm can be..


I agree... :)
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ike do you mind posting the nogaps link please?
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Quoting Patrap:



Naw...I just took a lot of frames and saw the motion..we all hve different takes on what is occurring,Kinda Like Models..we all have a role in the Big Pic.

Which I think is a good thing here,always Kman.


Well, your take was correct. 94L is a tricky one. Looked like a TD from this morning but was still a wave then.

I am now seeing what looks like a surface low trying to consolidate right on 15N 52W but want to see another 4 frames to determine if that is so.

It doesn't seem to be going anywhere in a hurry though. Lots of action in the mid levels in the NE quad of the overall envelope.
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geez these storms are being ripped apart like paper this year. Theres barely any shear but 94l is just struggling. back tomorrow, ill be really upset if we dont have a TD.


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Quoting TheCaneWhisperer:



Wonder why? Very Consistent. Even TAFB thinks this will get into the Caribbean


If it becomes at TD later this afternoon the track will likely take it just north of the Lesser Antilles
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test
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Quoting TexasHurricane:


Don't be asking about a GOM storm...people may think we are wishcasting... :)

It's way too early to tell where it will end up in over 5 days, IMO.
Everywhere from Texas up the east coast of US should watch for now because we all have seen how unpredictable a storm can be..
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12PM AST

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235. IKE
Some models have it heading north eventually. Some have it going west. Some have it going WNW. Latest NOGAPS has it off of the east central Florida coast at 192 hours.

These models are wearing and tearing on me.......
Member Since: June 9, 2005 Posts: 23 Comments: 37860
It is sad, that just because you give your opinion and you are trying to be pro-active and trying to look out for your family,we are called troll and wishcasters
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This is the 126 hour HWRF forecast. Looks scary, but most agree it may be a little over-done. Most agree, at this time, a CAT 4 may be unlikely. Just showing a graphic, not endorsing it. Got to be careful on the blog.
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This has been a weird summer. August 31, high of 73 today here in Eastern NC. Lows hit mid 30's in Michigan today....wth?
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Quoting kmanislander:
Hi Pat,

You were right last night. That ULL pulled 94L to the N



Naw...I just took a lot of frames and saw the motion..we all have different takes on what is occurring,Kinda Like Models..we all have a role in the Big Pic.

Which I think is a good thing here,always Kman.
Member Since: July 3, 2005 Posts: 426 Comments: 129093
TD at 5
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Mornin folks. "Lurk reading" this morning while getting ready for work. I've seen a few mentions of a low developing off the trough, in the gulf. Tallahassee seems to be keeping an eye on this as well. Something fun to watch develop...or not...and I have to work *snivels* Have a great day, all!!

Tallahassee AFD - See last two paragraphs
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ALL Floater Imagery
Member Since: July 3, 2005 Posts: 426 Comments: 129093
Quoting kmanislander:
Good day again

If you take a look at the vis loop in zoom it looks like the center of the circulation is sitting right on 15N 52 W and is becoming more apparent with each frame. The rotation just off to the NE from there seems to be at the mid levels to me.

I won't say which direction it looks to be heading in LOL

Vis Loop


I see clouds flying towards every direction.
Member Since: August 22, 2006 Posts: 2 Comments: 1988
Hi Pat,

You were right last night. That ULL pulled 94L to the N
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Quoting oddspeed:
chances of 94L on an Ike track?


no because of the trough.
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Quoting hurricane23:
12z CMC still recurve.



Wonder why? Very Consistent. Even TAFB thinks this will get into the Caribbean
Quoting hurricane23:
12z CMC still recurve.

WHEN?
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Quoting Weather456:
Why hasnt 94L need designated a TD? C'mon Danny look 5 times worse.


Maybe for the same reason Dolly wasn't even though it had 40 to 50 MPH winds; no closed surface low.
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Quoting oddspeed:
chances of 94L on an Ike track?


Don't be asking about a GOM storm...people may think we are wishcasting... :)
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I am a bit shocked a some on here already casting odds on South Florida or the Gulf for 94l. No need to cause any panic or unessesary fear until we actually have a TD or storm to actually track. The presentation looks good but NHC will not declare a TD or storm until they have firm evidence of a closed circulation near the surface....That will come from an actual Hunter mission tommorow, or, some very good satellite derived evidence of a closed low coupled with bouy observations as mentioned by Dr. M which can show winds converging in from the west-northwest at the surface levels.........It may still take some time so don't jump the gun on possible track.
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I'm interested in this possibility of a developing low off NC/SC on thursday. I have a beach wedding on Friday!
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Member Since: July 3, 2005 Posts: 426 Comments: 129093


In case some of you missed these this morning on the latest post.
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214. JLPR
Quoting fire635:


agreed.. I think its very likely that MLC will transfer down to a LLC within the next 12-24 hours, though


that's possible, or maybe the broad low would consolidate under the convection
Member Since: September 4, 2007 Posts: 36 Comments: 5223
NRVM
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12z CMC still recurve.
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211. JLPR
Quoting kmanislander:
Good day again

If you take a look at the vis loop in zoom it looks like the center of the circulation is sitting right on 15N 52 W and is becoming more apparent with each frame. The rotation just off to the NE from there seems to be at the mid levels to me.

I won't say which direction it looks to be heading in LOL

Vis Loop


that's what I said and everyone ignored me xD
they are denial since they want 94L to be a TD already
Member Since: September 4, 2007 Posts: 36 Comments: 5223
Good Afternoon all

September Outlook; Jimena; 94L

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Quoting JLPR:


nope Danny had a LLC 94L doesn't


agreed.. I think its very likely that MLC will transfer down to a LLC within the next 12-24 hours, though
Member Since: June 24, 2006 Posts: 0 Comments: 489
chances of 94L on an Ike track?
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Good day again

If you take a look at the vis loop in zoom it looks like the center of the circulation is sitting right on 15N 52 W and is becoming more apparent with each frame. The rotation just off to the NE from there seems to be at the mid levels to me.

I won't say which direction it looks to be heading in LOL

Vis Loop
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206. 7544
Quoting truecajun:
the bahama blob looks like it's trying to spin?? maybe??


looks like it and this is where we might see 94l or erika sitting in the same area in the coming days if the models hols lol
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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.