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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Quoting canesrule1:
Based on the latest models


fail.

are you really a PhD in meteorology, or were you kidding the other day?

Member Since: August 22, 2006 Posts: 2 Comments: 1983
A note on shear...

The shear affecting 94L is not at the upper levels - as the anti-cyclone is in place overtop the low.

However, it appears that stronger easterly mid-level (700mb) flow has elongated the circulation a bit...and this is where the shear is being felt.
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Quoting CycloneOz:
Question: Is Cantore here? and if so...where exactly?

Thanks to the person who knows...
HE IS IN CABO..ON THE BEACH WEARING HIS BLACK T-SHIRT AND HAT, HOLDING A TREE
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Quoting P451:
Those who feel this is a well organized system that should be named TS Erika soon - I just have to disagree.

There is a very broad circulation with the system and a very broad and elongated circulation center that is roughly between the two areas of convection. If you look hard enough you can see the lower level grey swirl taking place west of the larger area of convection. The Eastern side of this rotation does pass under and through the large area of convection however the center of this low level circulation is not under the convection itself.

There is also a lot of southerly shear apparent and you can easily see that with the TStorm tops being ripped northward. Note the black streamers leaving the convection, most evident on the western area of convection.

While I feel this system has promise I don't feel it is all that well organized and don't expect any rapid intensification until it becomes more organized. I can see why the 2PM TWO stated that it's in a marginal environment.

ShortWave Imagery Loop:



My uneducated analysis on what I see in that loop:



Good description. Thats why it will keep heading W,WNW.
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Hello friends, I'll be uptdating my blog, I have live cameras adn weather stations! it is raining right now in cabo san lucas.
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1099. Patrap

Jimena Floater - Visible Loop
Member Since: July 3, 2005 Posts: 426 Comments: 128636
..
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1096. Relix
Quoting farhaonhebrew:
that is bad for us in Puerto Rico..


Should pass north of us honestly. We might feel some rains and gusts, that's about it. Or it could be a darn sunny day.
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1095. jipmg
Quoting BrockBerlin:


almost, at least based on NHC data.


yea this site has a 5 on jimena, but its actually 155mph winds LOL
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Quoting Patrap:


I'll Light a Candle for ya Here in New Orleans at St. Louis Cathedral.

I Have a event there tonight Oz.
Be safe.
Take no undue risk .


Thanks Pat...indeed...no undue risk.
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Quoting sammywammybamy:


South Palm Beach County Here..


Yep, Boca Raton was one of the hardest hit areas and some say that the east coast was worst than the west coast.Boca Raton airport recorded a wind gust over 120mph sometime around 7-8am.
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Quoting CaicosRetiredSailor:


It is blank for me at this time


In order to see the webcam, you have to download the abacast.com plugin.
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HURRICANE JIMENA DISCUSSION NUMBER 13
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP132009
200 PM PDT MON AUG 31 2009>>>>

I love their time stamp seeing as it's just 1:41 PM PDT right now.
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1089. Patrap
Quoting CycloneOz:


I brought the Cat V suit. I intend to use it as it was designed.

Lots of concrete structures in Cabo...just like in Bermuda. The problem is going to be flying debris...and maybe flooding. My suit can handle both. I'm going out in it...no matter how bad this little buzz saw is...


I'll Light a Candle for ya Here in New Orleans at St. Louis Cathedral.

I Have a event there tonight Oz.
Be safe.
Take no undue risk .
Member Since: July 3, 2005 Posts: 426 Comments: 128636
MY PERCENTAGES!!!!!

Based on the latest models

Eastern U.S.A coast: 91%

Out-to-sea: 9%
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Quoting CycloneOz:
That is the best live webcam shot I have...


It is blank for me at this time
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Question: Is Cantore here? and if so...where exactly?

Thanks to the person who knows...
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1083. JLPR
very well not much to discuss for the moment

im out till later tonight
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Quoting serialteg:


Happy birthday, that cane brought epic surf to the south coast of PR as told by my parents and uncles


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Looks like 94L will survive the diurnal cycle. A big + when looking at qualifications.
the 5:oo is out..ITS LIKE A "ANDREW"
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can someone tell me how strong the models are forecasting 94l to get eventually? thank you. please put it in terms of how someone who isnt a weather genius would understand. tia
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Quoting Patrap:
Hurricane Jimena Floater - JSL Color Infrared Loop

IF you can check the Trop Forecast Points Box CycloneOZ,..

Id consider the fact if she Stays on Trend and guidance,your going to be very Near or In the right front Quad.

I advise EXTREME caution and to stay indoors for this one.



I brought the Cat V suit. I intend to use it as it was designed.

Lots of concrete structures in Cabo...just like in Bermuda. The problem is going to be flying debris...and maybe flooding. My suit can handle both. I'm going out in it...no matter how bad this little buzz saw is...
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1075. Grothar
NOAA Hurricane Hunters estimated Wilma had sustained winds of around 120-mph when the eye crossed the southwest Florida coast. The highest sustained wind measured at an official observing site was 92-mph (15-min average) from a South Florida Water observation site. Numerous official reporting sites measured peak gusts in the 100 to 115-mph range throughout southwest and southeast Florida. Unofficially, several measurements of intense winds were noted - including a gust of 125-mph at the Collier County Emergency Operations Center, and a gust of 135-mph by storm chaser Mark Sudduth who was in Everglades City were the center crossed the coast of the mainland. Below is a brief list of the highest winds (official & unofficial ) measured during Hurricane Wilma's passage across south Florida (Tropical Cyclone Report - Pasch,Blake,Cobb, and Roberts 1/12/2006)
Marco Island 135-mph gust.
Everglades City -Mark Suddath HLP Tower 135-mph gust.
Dry Tortugas Nat'l Park 133-mph gust.
Collier County EOC 125-mph gust.
Fowey Rocks (FWYF1) 123-mph gust.
Pompano Beach 120-mph gust.
W Boynton Beach (KFLBOYNT4) 90-mph winds/gust - 118-mph.
Weston (FCMP Tower T1)89-mph winds/gust 106-mph.
Naples Pier (NPSF1,NOS) 84-mph winds/gust - 102-mph
Opa Locka (KOPF) 85-mph winds/gust - 105-mph.
West Palm Beach (KPBI) 82-mph winds/gust - 101-mph.
Key West (KEYW) 71-mph winds/gust - 82-mph.

However, there were reports of higher unofficial gusts

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Link


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1072. jipmg
Looks like we now have a CATEGORY 5 headed towards Baja..
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Quoting Relix:


Since QuickSAT has a bias, and altest repot was 14.7... I would say about 15.1 =P
that is bad for us in Puerto Rico..
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hay i'm a lurker but learn a lot from all of ya'll this is what i see. the ull to west of 94l is filling in, the ull to the north of 94l is pulling away..time will only tell..just my take..
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1068. fmbill
18z NAM 60hours

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1067. Patrap
Southerly Shear as we head into the Low Angle afternoon Viz Images

Member Since: July 3, 2005 Posts: 426 Comments: 128636
Quoting tmangray:
Part of the problem with 94L may also be its passage over the cooler wake of Bill.


If it heads poleward, maybe, otherwise no.

Oceanic Heat Content
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WTPZ33 KNHC 312033
TCPEP3
BULLETIN
HURRICANE JIMENA ADVISORY NUMBER 13
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP132009
200 PM PDT MON AUG 31 2009

...JIMENA ALMOST A CATEGORY FIVE HURRICANE...

A HURRICANE WARNING IS IN EFFECT FOR THE SOUTHERN PORTION OF THE
BAJA CALIFORNIA PENINSULA FROM BAHIA MAGDALENA SOUTHWARD ON THE
WEST COAST...AND FROM SAN EVARISTO SOUTHWARD ON THE EAST COAST...
INCLUDING CABO SAN LUCAS. A HURRICANE WARNING MEANS THAT HURRICANE
CONDITIONS ARE EXPECTED SOMEWHERE WITHIN THE WARNING AREA WITHIN 24
HOURS. PREPARATIONS TO PROTECT LIFE AND PROPERTY SHOULD BE RUSHED
TO COMPLETION.

A HURRICANE WATCH IS IN EFFECT FOR THE BAJA CALIFORNIA PENINSULA
NORTH OF BAHIA MAGDALENA ON THE WEST COAST TO PUNTA ABREOJOS...AND
NORTH OF SAN EVARISTO TO MULEGE ON THE EAST COAST. A HURRICANE
WATCH MEANS THAT HURRICANE CONDITIONS ARE POSSIBLE WITHIN THE WATCH
AREA...GENERALLY WITHIN 36 HOURS.

INTERESTS ELSEWHERE IN THE CENTRAL BAJA CALIFORNIA PENINSULA AND IN
WESTERN MAINLAND MEXICO SHOULD MONITOR THE PROGRESS OF JIMENA.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA...PLEASE MONITOR
PRODUCTS ISSUED BY YOUR NATIONAL METEOROLOGICAL SERVICE.

AT 200 PM PDT...2100 UTC...THE CENTER OF HURRICANE JIMENA WAS
LOCATED NEAR LATITUDE 18.5 NORTH...LONGITUDE 109.2 WEST OR ABOUT
305 MILES...495 KM...SOUTH OF CABO SAN LUCAS MEXICO.

JIMENA IS MOVING TOWARD THE NORTHWEST NEAR 10 MPH...17 KM/HR...AND A
TURN TOWARD THE NORTH-NORTHWEST WITH A GRADUAL INCREASE IN FORWARD
SPEED IS EXPECTED OVER THE NEXT DAY OR SO. ON THE FORECAST TRACK...
JIMENA WILL BE APPROACHING THE SOUTHERN PORTION OF THE BAJA
CALIFORNIA PENINSULA ON TUESDAY.

REPORTS FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INDICATE
THAT THE MAXIMUM SUSTAINED WINDS ARE NEAR 155 MPH...250 KM/HR...
WITH HIGHER GUSTS. JIMENA IS A CATEGORY FOUR HURRICANE ON THE
SAFFIR-SIMPSON SCALE...AND VERY NEAR THE THRESHOLD OF CATEGORY FIVE
STATUS. SOME FLUCTUATIONS IN STRENGTH ARE LIKELY DURING THE NEXT
DAY OR SO...BUT JIMENA IS EXPECTED TO REMAIN A MAJOR HURRICANE
UNTIL LANDFALL.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 45 MILES...75 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 140
MILES...220 KM.

THE MINIMUM CENTRAL PRESSURE REPORTED BY THE AIR FORCE RESERVE
HURRICANE HUNTER PLANE IS 931 MB...27.49 INCHES.

JIMENA IS EXPECTED TO PRODUCE TOTAL RAIN ACCUMULATIONS OF 5 TO 10
INCHES OVER THE SOUTHERN HALF OF THE BAJA CALIFORNIA PENINSULA AND
PORTIONS OF WESTERN MEXICO DURING THE NEXT 2 DAYS...WITH POSSIBLE
ISOLATED MAXIMUM AMOUNTS OF 15 INCHES.

A DANGEROUS STORM SURGE ALONG WITH BATTERING WAVES WILL PRODUCE
SIGNIFICANT COASTAL FLOODING ALONG THE BAJA CALIFORNIA PENINSULA.

...SUMMARY OF 200 PM PDT INFORMATION...
LOCATION...18.5N 109.2W
MAXIMUM SUSTAINED WINDS...155 MPH
PRESENT MOVEMENT...NORTHWEST OR 315 DEGREES AT 10 MPH
MINIMUM CENTRAL PRESSURE...931 MB

AN INTERMEDIATE ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE
CENTER AT 500 PM PDT FOLLOWED BY THE NEXT COMPLETE ADVISORY AT 800
PM PDT.

$$
FORECASTER PASCH
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Quoting serialteg:


Look for the buoys while I go make myself something to eat :D


please bring me a drink while you're at it - make it gin....this is killin' me. :)
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1061. divdog
Quoting IKE:


I agree.

I always loop the visible and speed it up. Shear is hammering it right now.
I'll still go with Dr. Masters and his expertise.
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The vapor loop shows that Jimena has easily digested a slot of dry air, probably with a boost from neighboring Kevin which is fallng apart.
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Quoting caneluver:


My god what are you people smoking? Did you not read Dr. Masters Blog?

he's wrong, it happens.

Ships was showing favorable shear, not the cimss map or the euro model.
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1057. A4Guy
If you look at the NHC report from Wilma, you can find the nearest location reporting winds (Probably Pompano airport).
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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.