Potentially dangerous 92L steadily developing; Igor nears hurricane strength

By: Dr. Jeff Masters , 3:04 PM GMT on September 11, 2010

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A tropical disturbance (92L) over the Eastern Caribbean, a few hundred miles south of Puerto Rico, is steadily organizing and appears likely to develop into a tropical depression by tonight or Sunday morning. Satellite loops show an impressive and expanding region of heavy thunderstorms, with good spiral banding and respectable upper-level outflow on all sides. Long range radar out of Puerto Rico shows that heavy rains are now affecting that island, but there is no rotation to the radar echoes evident. However, the rain bands are becoming more intense and more organized. San Juan, Puerto Rico reported a heavy rain squall at 8:44 am this morning, and radar estimates suggest two inches of rain fell in this squall just southeast of San Juan. Wind shear over 92L is low, 5 - 10 knots. The waters beneath are at near-record warmth, 30°C, and these warm waters extend to great depth. Water vapor satellite loops show a large area of dry air lies to the north and west of 92L, and this dry air could interfere with development at times over the next few days.


Figure 1. Morning satellite image of 92L.

Track forecast for 92L
The disturbance is moving west-northwest at 11 mph, and steering currents favor a continuation of this motion for the next three days. Model support for development is scattered. The GFS and NOGAPS models do not develop 92L. The GFDL and ECMWF models predict development, with a track taking 92L into Mexico's Yucatan Peninsula on Wednesday. The HWRF model has a more northwesterly track, taking 92L over the Dominican Republic, Haiti, and Cuba, but this model has been trending too far north in its tracks. I expect 92L will follow a path south of the islands, bringing it near or just south of Jamaica on Monday, then into the Yucatan Peninsula on Wednesday. On this track, the southern Dominican Republic can expect heavy rains of 3 - 6 inches tonight through Monday morning; southern Haiti can expect similar rains Sunday through Monday, and Jamaica and the Cayman Islands can expect heavier rains of 4 - 8 inches Monday and Tuesday. Eastern Cuba will probably escape 92L's heaviest rains in this scenario (Figure 2.)

Intensity forecast for 92L
I can't find any reason to doubt this will be a tropical storm by Sunday or Monday, and potentially a Category 1 or 2 hurricane by Wednesday, if 92L avoids passage over Hispaniola and Cuba. The SHIPS model predicts wind shear will remain low, 5 - 10 knots, through the period, and makes 92L a Category 1 hurricane by Monday night. Water temperatures are certainly warm enough to support development. The main detriment to intensification is likely to be dry air, and 92L could wrap in some of the dry air to its northwest at times, slowing down development. The first Air Force Hurricane Hunter mission into 92L is scheduled for Sunday afternoon, but there will be a research mission by the National Center for Atmospheric Research G-V jet today that will give us valuable information on 92L's large scale environment and potential for development.


Figure 2. Forecast rain amounts from 92L from the 2am EDT Saturday run of the GFDL model. This model predicts most of 92L's heaviest rains will miss Haiti, but will affect Jamaica, the Cayman Islands, and the Yucatan Peninsula. Image credit: Morris Bender, NOAA/GFDL.

Igor
Tropical Storm Igor is very close to hurricane strength, and appears destined to become a large and powerful major hurricane over the Central Atlantic in the days to come. Wind shear is moderate, 15 - 20 knots, waters are warm, 28°C, and Igor has moistened its environment enough to keep the dry air of the Saharan Air Layer (SAL) at bay. Igor will track west under the influence of a strong ridge of high pressure for the next three days, then turn more to the west-northwest in response to the steering influence of a broad trough of low pressure moving across the Western Atlantic on Tuesday and Wednesday. This should allow Igor to pass several hundred miles to the northeast of the Lesser Antilles. In the longer range, Igor may be a threat to Bermuda, and has a slight chance of making landfall on the U.S. East Coast or Canada. Climatology shows that about 10% of all tropical cyclones that have existed at Igor's current position have gone on to hit the U.S. East Coast; these odds are about 10% for Bermuda and 5% for Canada. The forecast steering pattern for the coming two weeks from the GFS model shows a continuation of the pattern we've seen all hurricane season, with regular strong troughs of low pressure moving off the U.S. East Coast. This pattern favors Igor eventually recurving out to sea without affecting any land areas. The odds of Igor hitting land in the U.S. or Canada are probably close to their climatological 10% and 5% probabilities, respectively.

Elsewhere in the tropics
A new tropical wave (Invest 93L) emerged from the coast of Africa yesterday, and is already showing signs of organization. Most of the models predict 93L will develop into a tropical depression 2 - 4 days from now, and NHC is giving 93L a 30% chance of developing by Monday.

Next post
This may be my only post today; I'll have a new post Sunday morning.

Jeff Masters

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2573. barotropic
12:48 PM GMT on September 13, 2010
Member Since: August 22, 2010 Posts: 0 Comments: 652
2572. wunderkidcayman
2:27 PM GMT on September 12, 2010
yes stormwatcher... hey are you ready for the system when it comes Tue-Wed night/Thurs morn
Member Since: June 13, 2009 Posts: 2 Comments: 12163
2571. SLU
2:26 PM GMT on September 12, 2010
NOW TIME TO MOVE OVER TO THE NEW BLOG!!!
Member Since: July 13, 2006 Posts: 13 Comments: 5261
2568. stormwatcherCI
2:25 PM GMT on September 12, 2010



92L looking better ATM.
Member Since: October 9, 2008 Posts: 0 Comments: 8393
2567. SLU
2:25 PM GMT on September 12, 2010
93L is now TD12
Member Since: July 13, 2006 Posts: 13 Comments: 5261
2566. ChrisDubois
2:24 PM GMT on September 12, 2010
I think the NHC predicted a Major by Tuesday sometime. This system will def. become a major late this evening if it's not already. Look at the eye formation. I have never seen an eye look so good on a 80mph storm. We should see the winds increased on the 11am advisory
Member Since: July 23, 2010 Posts: 0 Comments: 28
2565. TheDawnAwakening
2:24 PM GMT on September 12, 2010
Igor should be a Major hurricane at 11am advisory this morning, very impressive RI this morning.
Member Since: October 21, 2008 Posts: 246 Comments: 3947
2564. extreme236
2:23 PM GMT on September 12, 2010
92L looks more impressive again this morning, but we saw the same thing yesterday morning. We'll have to see if it persists this time.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
2563. TheDawnAwakening
2:23 PM GMT on September 12, 2010
Models are beginning to agree on a strong positive NAO signal towards the end of the month. THis is the pattern change we have been waiting for, in regards to potential Eastern US landfalls. However it is still long range, so it could still change some over the next 5 days.
Member Since: October 21, 2008 Posts: 246 Comments: 3947
2562. kimoskee
2:23 PM GMT on September 12, 2010
Cuban Radar
Link
Member Since: August 17, 2008 Posts: 0 Comments: 672
2560. extreme236
2:22 PM GMT on September 12, 2010
Igor is likely a major hurricane right now. ADT definitely supports that.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
2559. stormwatcherCI
2:20 PM GMT on September 12, 2010
Latest info from NRL on 92L. Pressure down 1mb.
If I am understanding this correctly pressure supports a TD but winds only 30mph. Pressure drop should be a sign of organization happening. Correct ?


92LINVEST.25kts-1007mb-157N-707W
Member Since: October 9, 2008 Posts: 0 Comments: 8393
2558. doorman79
2:20 PM GMT on September 12, 2010
Quoting Patrap:
Be sure to include a NOAA weather Alert Radio in your Home ,,it just may save yer Life one Night or Day.



Yea, those things are great for more than just tropical weather. I have one for when the fronts start coming through. Sometimes they have some nasty weather as you know.
Member Since: August 11, 2010 Posts: 0 Comments: 895
2557. Patrap
2:20 PM GMT on September 12, 2010
New Entry folks.

Make the Jump to hyper-Blog
Member Since: July 3, 2005 Posts: 426 Comments: 128690
2556. hurricanehunter27
2:20 PM GMT on September 12, 2010
New sat pic on Igor and he is looken better evey 30 min!

Member Since: July 22, 2010 Posts: 1 Comments: 3842
2554. AtHomeInTX
2:19 PM GMT on September 12, 2010
Brownsville...

.LONG TERM...7 PM MONDAY THROUGH SATURDAY...A BROAD AND ELONGATED
MID LEVEL RIDGE WILL REMAIN ANCHORED OVER DEEP SOUTH TX FOR MUCH
OF THIS UPCOMING WEEK MAINTAINING GENERALLY ABOVE NORMAL TEMPS.
THE OVERALL MOISTURE VALUES WILL BE FAIRLY LACKING FOR MUCH OF THIS
UPCOMING WEEK WHICH WILL LIKELY LIMIT THE CONV POTENTIAL. HOWEVER
LOOKING EAST INTO THE THE EASTERN CARIB SEA NHC CONTINUES TO MONITOR
A BROAD AREA OF LOW PRESSURE FOR POSSIBLE DEVELOPMENT. THE LATEST
ECMWF AND GFS INDICATE THAT THIS FEATURE WILL CONTINUE MOVING WEST
TOWARDS THE YUCATAN PENINSULA EVENTUALLY MOVING INTO THE SW GULF
OF MEX ON THURS. THE ECMWF SHOWS STRONGER DEVELOPMENT OF THIS
FEATURE VERSUS THE GFS WHICH SHOWS A BROADER LESS DEVELOPED SURFACE
LOW. REGARDLESS OF THE LEVEL OF DEVELOPMENT OF THIS FEATURE EXPECT
SOME DEEPER TROPICAL MOISTURE TO START ADVECTING ACROSS DEEP SOUTH
TX ON FRI AND SAT RESULTING IN SOME BETTER CONV POTENTIAL LATE IN
THE EXTENDED RANGE PERIOD. RUN TO RUN CONSISTENCY WITH THE LATEST
GFS MEX MOS TEMPS AND POPS IS PRETTY GOOD AND MODEL TO MODEL
COMPARISON BETWEEN THE GFS AND ECMWF ALSO SHOWS DECENT CONSISTENCY.
WILL LEAN CLOSE TO THE GFS MEX MOS TEMPS AND POPS IN THE 3 TO 7
DAY RANGE. PLEASE REFER TO THE LATEST OUTLOOK AND FORECASTS FROM
NHC CONCERNING THE PROGRESS OF THIS SYSTEM IN THE CARIB SEA.

MARINE...TODAY THROUGH 7 PM MONDAY...AT 1 AM BUOY 20 REPORTED EAST
SOUTHEAST WINDS AT 12 KNOTS WITH GUSTS TO 14 KNOTS AND SEAS AT 2
FEET WITH A 5 SECOND PERIOD. THE WINDS WILL CONTINUE LIGHT TO
MODERATE FROM THE SOUTHEAST TO EAST THE NEXT FEW DAYS. THE SEAS WILL
REMAIN LOW THROUGH MONDAY. THE EXTENDED MARINE FORECAST PERIOD
CONDITIONS WILL DEPEND GREATLY ON THE OVER MOVEMENT AND DEVELOPMENT
OF THE BROAD SURFACE LOW IN THE EASTERN CARIB SEA. A STRONGER MORE
NORTHWARD TRACKING SYSTEM WILL RESULT IN HIGHER WINDS AND SEAS
TOWARDS NEXT WEEKEND WHILE A WEAKER MORE SOUTHWARD SYSTEM WILL
HAVE MUCH LESS OF AN IMPACT ON THE LOWER TX MARINE CONDITIONS. FOR
NOW WILL GO WITH A MORE CONSERVATIVE WIND AND SWELL FORECAST FOR
THE LATER MARINE PERIODS. AT THIS TIME NO SCA CONDITIONS EXPECTED.
&&


Member Since: August 24, 2010 Posts: 0 Comments: 245
2553. ChrisDubois
2:19 PM GMT on September 12, 2010
IMO Igor is definetly a Cat 2 right now with winds of 105mph
Member Since: July 23, 2010 Posts: 0 Comments: 28
2552. breald
2:18 PM GMT on September 12, 2010
Quoting cat5hurricane:
Didn't know you can get these at Radio Shack... Cool


Home Depot too. At least the ones in Florida you can buy them.
Member Since: May 28, 2008 Posts: 38 Comments: 5303
2551. Seastep
2:18 PM GMT on September 12, 2010
Looking at the pattern in all the latest model runs, all except the GFS shows basically the same pattern progression over the eastern seaboard, similar to the euro.
Member Since: September 9, 2008 Posts: 6 Comments: 3414
2550. stillwaiting
2:18 PM GMT on September 12, 2010
Quoting lhwhelk:

I evacuated from Rita (a bust for us) and from Ike. When I came back from Ike and saw the damage a Cat 2 could do (I was on the "good" side and not in a storm surge location), I decided then that I will not even ride out a Cat 1. All it takes to let you see that is a tree falling on your house. "Amazing pics" aren't worth your life.
......true but there are more trees inland than on the beach,theirs a saying. When it comes to hurricane that goes"hide from the wind,run from the water,here on a island im far more concerned w/surge than anything else 6foot rise floods most of the island.......that's why it'd evacuate,not wind......
Member Since: October 5, 2007 Posts: 20 Comments: 4970
2548. TampaSpin
2:15 PM GMT on September 12, 2010
Quoting cat5hurricane:
Anyone know the most reliable, accurate model in the Atlantic...approximately where Igor is? Is it the GFS?


I perfer the NOGAPS but, this time i hope not because the Carolina's are in for it on this run.



Member Since: September 2, 2007 Posts: 178 Comments: 20443
2547. Patrap
2:15 PM GMT on September 12, 2010
Be sure to include a NOAA weather Alert Radio in your Home ,,it just may save yer Life one Night or Day.

Member Since: July 3, 2005 Posts: 426 Comments: 128690
2545. Patrap
2:13 PM GMT on September 12, 2010
Quoting doorman79:
Say hello to my ex while you are there lol!


Absolutely..

LOL
Member Since: July 3, 2005 Posts: 426 Comments: 128690
2544. doorman79
2:12 PM GMT on September 12, 2010
Say hello to my ex while you are there lol!
Member Since: August 11, 2010 Posts: 0 Comments: 895
2543. WeatherNerdPR
2:12 PM GMT on September 12, 2010
Quoting RecordSeason:
Gotta say some things about 92L.


It looks weak still, but the potential is definitely there for TD soon and intensification to hurricane sometime in the near future.

There is an anticyclone over it right now, and it's starting to get out of the dead zone.

===

Now my synoposis of what TWC is probably saying about Igor right now:

"Igor is a minimum category 1 hurricane, with no signs of further development at this time. Stay tuned with the Weather Channel for all your up-to-date information about the tropics. Let's get back to Al Roker in the studio for Wake Up With Al."

TWC is sooo wrong.
Member Since: July 7, 2010 Posts: 0 Comments: 5690
2542. stillwaiting
2:11 PM GMT on September 12, 2010
Quoting surfmom:
Up ST.Pete - beach there faces exactly like Siesta - so what happens there, happens here.

SeaSTEP
- Yikes -- a flea -- he was a flea out there..can you imagine his poooooor Mother...ahhh BoYZZ
This is my favorite vid so far to come from our Canes this year - Hurricane Earl Surf footage
Link
....makes sense as far as i know their are no live siesta key beach cams,county should install a few imo,they(we)would be able to keep tabs on anything happening at the beaches from remote locations!!!!
Member Since: October 5, 2007 Posts: 20 Comments: 4970
2541. Patrap
2:11 PM GMT on September 12, 2010
Quoting doorman79:


Good Morning Pat,
How is all in da city. Can't wait for a good cool snap so i can take the kids to monkey hill!



Good morn' bac atcha..

Fine Morning here...clear.but Septemberish still.

going to Walk da Park in few myself.

Current Conditions

Uptown, New Orleans, Louisiana (PWS)
Updated: 1 min 53 sec ago
Scattered Clouds
84.5 F
Scattered Clouds
Humidity: 88%
Dew Point: 80 F
Wind: Calm
Wind Gust: 4.0 mph
Pressure: 30.06 in (Rising)
Heat Index: 99 F
Visibility: 10.0 miles
UV: 2 out of 16
Pollen: 8.80 out of 12
Pollen Forecast new!
Clouds:
Few 2000 ft
Scattered Clouds 25000 ft
(Above Ground Level)
Elevation: 20 ft
Member Since: July 3, 2005 Posts: 426 Comments: 128690
2540. Patrap
2:10 PM GMT on September 12, 2010
Sometimes Logic dictates that one HAS to hit the Minus button.

Member Since: July 3, 2005 Posts: 426 Comments: 128690
2539. doorman79
2:10 PM GMT on September 12, 2010
Quoting Patrap:






Hurricane Preparation 2010


Good Morning Pat,
How is all in da city. Can't wait for a good cool snap so i can take the kids to monkey hill!
Member Since: August 11, 2010 Posts: 0 Comments: 895
2537. Cantu5977
2:08 PM GMT on September 12, 2010


Does it look like a developing system??
Member Since: May 9, 2006 Posts: 0 Comments: 89
2536. A4Guy
2:08 PM GMT on September 12, 2010
TD12 is here!
Member Since: June 23, 2006 Posts: 0 Comments: 668
2535. AtHomeInTX
2:07 PM GMT on September 12, 2010
Quoting Cantu5977:


Interesting ECMWF has been to strong with the ridges this tropical season and the GFS to weak lol



Yeah they should come with a warning message, "Don't follow models too closely. They'll make your head spin>" Lol.
Member Since: August 24, 2010 Posts: 0 Comments: 245
2534. stormwatcherCI
2:07 PM GMT on September 12, 2010
Quoting GeoffreyWPB:
Looking at this you can see the spin around 15N/71W and looks like although most of the convection is on the northern side it is beginning to slowly wrap some on the southern side.
Member Since: October 9, 2008 Posts: 0 Comments: 8393
2533. ackee
2:07 PM GMT on September 12, 2010
92L looks like want make suprise past by jamaica may be another gustav not but lot weaker
Member Since: July 15, 2008 Posts: 0 Comments: 1373
2531. atmoaggie
2:06 PM GMT on September 12, 2010
Quoting extreme236:


Any readings I saw that were that high were above the usual flight level, or were from dropsondes. The data may or may not have been accurate, but the NHC doesn't hold back on wind readings that high if their legitimate.
Afraid you're wasting your time, there.
Member Since: August 16, 2007 Posts: 6 Comments: 12463
2528. Vero1
2:05 PM GMT on September 12, 2010
Member Since: July 21, 2008 Posts: 4 Comments: 2233
2527. Seastep
2:05 PM GMT on September 12, 2010
Nice, surfmom. Thanks. Nice morning tune to go with my java, too.

Woke up last night and couldn't resist checking out the loops after getting some water.

Igor was really ramping up and I see that is continuing.

Waiting for some recon (two days). Like with Earl, all W of forecast. But, once they got some recon, they were pretty darn accurate.
Member Since: September 9, 2008 Posts: 6 Comments: 3414
2526. Sfloridacat5
2:04 PM GMT on September 12, 2010
Most people should not evacuate for a cat 1 hurricane unless you live in a flood prone area.
Member Since: September 16, 2007 Posts: 0 Comments: 7416
2525. MZT
2:04 PM GMT on September 12, 2010
Quoting wunderkidcayman:
92L has a COC and I still say TD 13 by 5pm
That has a familiar ring to it! ;-}
Member Since: September 24, 2005 Posts: 0 Comments: 793
2524. Patrap
2:04 PM GMT on September 12, 2010
Computer Models Used to Forecast Hurricanes -------->


The behavior of the atmosphere is governed by physical laws which can be expressed as mathematical equations. These equations represent how atmospheric quantities such as temperature, wind speed and direction, humidity, etc., will change from their initial current values (at the present time). If we can solve these equations, we will have a forecast. We can do this by sub-dividing the atmosphere into a 3-D grid of points and solving these equations at each point. These models have three main sources of error:
Member Since: July 3, 2005 Posts: 426 Comments: 128690
2523. surfmom
2:04 PM GMT on September 12, 2010
Because I care not only about my waters the Gomex I'm posting this link for my Carib Friends... looks like there's trouble in your paradise too--
Another Oil Disaster, This Time in the Caribbean Link
It's a question, of course, that has been repeated recently throughout Gulf Coast communities in the United States; in Michigan in July when a burst pipeline dumped 800,000 gallons of oil into the Kalamazoo River; and in scores of other places around the world where petroleum regularly leaks, gushes, explodes or burns -- without attracting all the media attention devoted to the BP disaster in our backyard.
Member Since: July 18, 2007 Posts: 30 Comments: 26536

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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.