Potentially dangerous 92L steadily developing; Igor nears hurricane strength
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
Reader Comments
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Yep.
Quite possibly. Watch it carefully.
morning Kori!
Good morning!
I was just looking at the IR Channel 2 loop and the circulation looks really good and it may have tucked under the SW corner of the convection to the NE.
Hope not....does seem like one of the models last week was trying to develop something in BOC or off Yukatan though
Anyone wanna guess when the last time we had a season that had all of its storm above 1 in ACE?
Harder one: From 1875 (when storm records became a little bit more complete), when was the first time there was a storm below 0.5000 in ACE?
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 AM EDT SUN SEP 12 2010
FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...
THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON HURRICANE
IGOR...LOCATED ABOUT 1230 MILES EAST OF THE NORTHERN LEEWARD
ISLANDS.
SHOWERS AND THUNDERSTORMS REMAIN DISORGANIZED IN ASSOCIATION WITH A
BROAD AREA OF LOW PRESSURE LOCATED OVER THE EAST-CENTRAL CARIBBEAN
SEA. ENVIRONMENTAL CONDITIONS STILL APPEAR FAVORABLE FOR GRADUAL
DEVELOPMENT OF THIS SYSTEM...AND A TROPICAL DEPRESSION COULD FORM
DURING THE NEXT COUPLE OF DAYS AS IT MOVES WESTWARD AT 10 TO 15
MPH. THERE IS A MEDIUM CHANCE...50 PERCENT...OF THIS SYSTEM
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. REGARDLESS
OF DEVELOPMENT...LOCALLY HEAVY RAINFALL IS POSSIBLE IN THE VIRGIN
ISLANDS...PUERTO RICO...HISPANIOLA...JAMAICA AND CUBA DURING THE
NEXT DAY OR TWO. THESE RAINS COULD CAUSE LIFE-THREATENING FLASH
FLOODS AND MUD SLIDES...ESPECIALLY IN MOUNTAINOUS TERRAIN.
SATELLITE DATA INDICATE THAT THE AREA OF LOW PRESSURE LOCATED ABOUT
315 MILES EAST-SOUTHEAST OF THE SOUTHERNMOST CAPE VERDE ISLANDS HAS
CONTINUED TO BECOME BETTER ORGANIZED...AND A TROPICAL DEPRESSION
APPEARS TO BE FORMING. IF CURRENT TRENDS CONTINUE...ADVISORIES
WILL BE INITIATED LATER THIS MORNING...AND WATCHES OR WARNINGS WILL
LIKELY BE REQUIRED FOR PORTIONS OF THE CAPE VERDE ISLANDS. THERE
IS A HIGH CHANCE...NEAR 100 PERCENT...OF THIS SYSTEM BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES GENERALLY
WESTWARD AT 10 TO 15 MPH.
A WEAK AREA OF LOW PRESSURE LOCATED ABOUT 900 MILES EAST-NORTHEAST
OF BERMUDA CONTINUES TO PRODUCE DISORGANIZED SHOWER ACTIVITY.
DEVELOPMENT OF THIS SYSTEM APPEARS UNLIKELY BEFORE IT IS ABSORBED
BY A FRONTAL SYSTEM IN THE NEXT DAY OR SO. THERE IS A LOW CHANCE
...10 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING
THE NEXT 48 HOURS AS IT MOVES NORTHWARD AT 20 TO 25 MPH.
ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.
$$
FORECASTER BRENNAN
I'd that is spot on. NOAA buoy at 15n/67.5w clearly shows the passage of the weak COC overnight.
°
09 12 6:50 am S 9.7 13.6 3.9 6 4.5 - 29.77 +0.01 83.5 86.4 76.1 - - -
09 12 5:50 am SSE 13.6 15.5 3.6 7 4.5 - 29.75 -0.02 84.2 86.4 76.6 - - -
09 12 4:50 am SE 11.7 13.6 3.3 6 4.7 - 29.75 -0.05 84.2 86.4 75.7 - - -
09 12 3:50 am SSE 9.7 13.6 3.3 6 4.9 - 29.76 -0.06 84.0 86.4 76.3 - - -
09 12 2:50 am SE 7.8 9.7 3.3 7 4.8 - 29.78 -0.05 83.8 86.5 76.1 - - -
09 12 1:50 am ESE 7.8 9.7 3.3 7 4.8 - 29.80 -0.01 84.0 86.5 75.4 - - -
09 12 12:50 am E 5.8 7.8 3.0 7 4.5 - 29.82 +0.03 84.0 86.5 75.4 - - -
09 11 11:50 pm E 9.7 11.7 3.6 7 4.6 - 29.83 +0.04 84.4 86.5 75.4 - - -
09 11 10:50 pm E 9.7 11.7 3.3 7 4.7 - 29.81 +0.02 84.4 86.5 75.4 - - -
09 11 9:50 pm ENE 11.7 13.6 3.3 7 4.3 - 29.79 +0.02 84.0 86.5 76.3 - - -
09 11 8:50 pm E 9.7 11.7 3.9 6 4.4 - 29.79 +0.01 84.0 86.5 75.6 - - -
And 92L goes backwards.. out comes the orange crayon.
Seems to be in a phase of Rapid Intensification.......I see a cat 3 by end of day...
Just like the models have been forecasting....92L struggles to get designated and 93L becomes the next TD and probably Karl.
Models show nothing threatening the northern gulf coast for at least the next 7 days...and maybe longer, which is great news.
Wow. Impressive.
I think 93L is going to get the jump on 92L and become Julia.
Yeah, hopefully 92L just does another Gaston - i.e. nothing. However, way too early to tell yet.
Good Morning! To answer your question (and I'm hypothetically speculating,) that may be the remnants of Gaston....
I meant to say 93L becomes Julia, not Karl.
jeepers is this a sneaky creeper????? any opinions why this won't BE a possible concern?
Couple the tracks with forecast intensity, and Igor could be retired.
Storm, you think the chances have increased today for a possible strike on the islands, despite the shift eastward (to right) by the NHC and model tracks?
92L looks to be just about on the 15 degree N lat line on a heading I would estimate to be 275/280 or due West. Still no real organization present and the 850 vort is not impressive at all. My expectations for this have always been for little to happen until after 75 W which it should get to soon.
The longer it takes to organize the better it will be for those downstream the system.
Could it be...Ex-Gaston?
I know I really hope he does not hit land as a cat 4. I know Bermuda has sturdy buildings but that would be devastating.
After taking a fall off a cliff, it appears that Gaston hadn't died after all! He strode toward the Beast's castle with fury and demonic rage.... :P
September 12, 2010 at 5:00 a.m.
LOCAL WEATHER FORECAST
SIGNIFICANT FEATURE…Trough across the central Caribbean, including Jamaica.
Comment
Comment… The Trough is expected to linger across the central and western Caribbean for the next three to four days
Maximum temperatures expected today:
Kingston… 33 degrees Celsius.
Montego Bay… 33 degrees Celsius.
24-HOURS FORECAST
This Morning… Partly cloudy across sections of northern parishes.
This Afternoon… Expect scattered showers and thunderstorms across sections of most parishes.
Tonight… Partly cloudy becoming fair.
3-DAYS FORECAST (starting tomorrow)
Tue… Periods of showers and thunderstorms across the island.
Wed/Thurs… Scattered afternoon showers and thunderstorms across central and western parishes
Regionally…
An area of Low Pressure across the southeastern Caribbean has a sixty percent chance for developing into a tropical cyclone and is expected to move into the central Caribbean, late tonight and be in the vicinity of Jamaica by late Monday night into Tuesday.
rlb
A greeting from Spain.
Hi there
I am about to get my coffee, I just heard the last gasp from the coffee maker LOL.
Not too much that is pressing tropically speaking this morning. 92L continuing to struggle with the less favourable Eastern and Central Caribbean and Igor seemingly on track for a recurve. Igor is about to intersect the 18 N lat line which is good news for the Leewards and a sign that the track is changing, albeit slowly at first.
As far as the future of 92L goes it has good upper level support and an excessive amount of ocean heat content to work with. It could still become a problem by early tomorrow if it starts to tap into the more generally conducive area in the Western Caribbean. For now we can be thankful it did not get going just outside the Caribbean.
Big Laugh out LOUD
Kinda like the Cat came back tune...cept we could sing "the Cane came back, they thought it was a gonner, but the Cane came back"......................
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