Hurricane Hunters to check out remains of Fred; 98L more organized
A tropical disturbance (98L), is located midway between Africa and the Lesser Antilles Islands. This disturbance has shown a modest increase in heavy thunderstorm activity over the past day. This morning's QuikSCAT pass showed an elongated circulation, with top winds around 30 mph. Wind shear is low, 5 - 10 knots, and Sea Surface Temperatures are 28°C, which is about 2°C above the 26°C threshold needed to support a tropical cyclone. There is a large amount of dry air to the north and west of 98L, and this dry air is interfering with development.
Wind shear over 98L is expected to remain in the low range, 5 - 10 knots, through Sunday evening, according to the SHIPS model. This may allow the storm to organize into a tropical depression, assuming it can fight off the dry air that surrounds it. By Monday, the SHIPS model predicts shear will increase to the high range, 15 - 30 knots, so in is unlikely 98L will become anything stronger thatn a weak tropical storm over the coming 5-day period. The models predict that a strong trough of low pressure will turn 98L to the northwest and then north beginning on Monday, with the result that 98L misses the Lesser Antilles Islands by at least 500 miles. NHC is giving 98L a high (greater than 50%) chance of developing into a tropical depression by Monday. At this time, it does not appear that 98L will ever threaten any land areas.
Fred-ex
The remains of Hurricane Fred are still spinning away about 700 miles east of Florida. There has been a modest increase in heavy thunderstorm activity on the south side of Fred's circulation over the past day, but high wind shear and dry air have kept the thunderstorms from building over Fred's center. Wind shear is moderate, 15 - 20 knots, and there is substantial dry air surrounding ex-Fred on all sides. This morning's QuikSCAT pass showed top winds of 30 mph.
None of the computer models develop ex-Fred, and conditions for development are expected to remain marginal over the next three days, with wind shear of 15 - 20 knots and plenty of dry air around. Most of the models predict ex-Fred should move over Florida on Tuesday, but steering currents may weaken early next week, and ex-Fred could end up slowing down and turning northwest towards South Carolina. A hurricane hunter aircraft this afternoon was cancelled.
Figure 1. Morning visible satellite image of 98L and the remains of Hurricane Fred.
Twenty years ago today
On September 19, 1989, Hurricane Hugo moved away from Puerto Rico, and headed northwest at 15 mph. An upper-level low over Georgia, in combination with the steering currents imparted by the Azores-Bermuda High, were responsible for the northwesterly motion of the storm. Wind shear from strong upper-level winds continued to weaken the hurricane, and Hugo diminished to a Category 2 hurricane with 105 mph winds.
Figure 2. GOES visible satellite image of Hurricane Hugo taken on September 19, 1989. Wind shear had weakened Hugo to a Category 2 storm with 105 mph winds. Image credit: Google Earth rendition of the NOAA HURSAT data base.
I'll have an update this afternoon if there's any major developments to report.
Jeff Masters
Reader Comments
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Overview
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At this time 98L continues to show signs of strengthening even though convection is waning. At 2PM EDT you can expect the NHC to keep it's red circle despite convection loss. Chances are we will have our next TD at 5PM. If convection continues to drop then you can expect a orange circle at 8PM and no TD. For right now we should continue to monitor its progress.
Track
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At this moment in time... Scenario #1, if 98L stays weak >40MPH, this will most likely run into Puerto Rico and then La Española, and will likely die out. Scenario #2, 98L's winds are between 41 to 73MPH it will most likely go north of the islands, Puerto Rico and then curve out to sea. Scenario #3, 98L has winds of <74MPH, it will most likely curve out to sea before it reaches the northern Antilles.
-MiamiHurricanes09
He comes on here and is being perfectly civil and you still go after him. Let it go!!
Flagged for administration.
Circulation is disorganized and broad. Looks like it's not taking advantage of those favorable conditions.
not as fast...
:D
Date: Near the closest hour of 16Z on the 19th day of the month
Highest Mandatory Level For Which Wind Was Reported: 400mb
Coordinates: 16.4N 63.1W (View map)
Location: 240 miles (386 km) to the SE (125°) from San Juan, Puerto Rico (USA).
Marsden Square: 043 (About)
Level Geo. Height Air Temp. Dew Point Wind Direction Wind Speed
1014mb (29.94 inHg) Sea Level (Surface) 28.2°C (82.8°F) 23.7°C (74.7°F) Unavailable
1000mb 121m (397 ft) 27.0°C (80.6°F) 23.4°C (74.1°F) 80° (from the E) 11 knots (13 mph)
925mb 807m (2,648 ft) 22.4°C (72.3°F) Approximately 17°C (63°F) 95° (from the E) 18 knots (21 mph)
850mb 1,539m (5,049 ft) 17.8°C (64.0°F) 14.6°C (58.3°F) 95° (from the E) 15 knots (17 mph)
700mb 3,178m (10,427 ft) 11.0°C (51.8°F) Approximately -14°C (7°F) 125° (from the SE) 13 knots (15 mph)
500mb 5,890m (19,324 ft) -6.7°C (19.9°F) Approximately -17°C (1°F) 175° (from the S) 4 knots (5 mph)
400mb 7,600m (24,934 ft) -10.9°C (12.4°F) Approximately -32°C (-26°F) 265° (from the W) 13 knots (15 mph)
How about that shear:)
ABNT20 KNHC 191732
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT SAT SEP 19 2009
FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...
A SURFACE TROUGH ASSOCIATED WITH THE REMNANTS OF FRED IS LOCATED
ABOUT 475 MILES EAST-NORTHEAST OF THE NORTHWESTERN BAHAMAS AND IS
PRODUCING DISORGANIZED SHOWERS AND THUNDERSTORMS. THIS SYSTEM HAS
BECOME LESS ORGANIZED DURING THE DAY AND THE RECONNAISSANCE MISSION
SCHEDULED FOR THIS AFTERNOON HAS BEEN CANCELED. THERE IS A LOW
CHANCE...LESS THAN 30 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES SLOWLY TOWARD THE
WEST-NORTHWEST.
SHOWER AND THUNDERSTORM ACTIVITY HAS DIMINISHED IN ASSOCIATION WITH
A BROAD AREA OF LOW PRESSURE CENTERED ABOUT 1200 MILES EAST OF THE
WINDWARD ISLANDS. HOWEVER...THIS SYSTEM STILL HAS THE POTENTIAL TO
BECOME A TROPICAL DEPRESSION OVER THE NEXT DAY OR TWO AS IT MOVES
TOWARD THE WEST-NORTHWEST AT AROUND 10 MPH. THERE IS A MEDIUM
CHANCE...30 TO 50 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS.
AN AREA OF DISTURBED WEATHER LOCATED A COUPLE HUNDRED MILES
NORTHEAST OF THE CAPE VERDE ISLANDS HAS BECOME LESS ORGANIZED OVER
THE PAST SEVERAL HOURS. DEVELOPMENT OF THIS SYSTEM IS NOT
ANTICIPATED AS IT MOVES TOWARD THE WEST-NORTHWEST AT ABOUT 10 MPH.
THERE IS A LOW CHANCE...LESS THAN 30 PERCENT...OF THIS SYSTEM
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.
ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.
$$
FORECASTER BLAKE
Agreed. It appears to have become part of the pre-frontal flow now as the circulation and associated convection has become elongated in response to the frontal boundary crossing very near to the north.
Yep too many variables
The interaction is creating convection to the N.
From what I see, it is not being absorbed. It is new convection. Absorbed would imply that the convection fired over Fred and was being pulled N. Quite the opposite is what I see. Convection firing to the N and moving S, towards Fred's coc. Which makes sense based on shear direction.
I think it will help Fred, actually. Introduces more moisture.
Judge for yourself. RAMSDIS Flash floater
part of my winter outlook. Drought relief coming to SE Texas. And most likely wetter conditions for the Southern USA. While below normal rainfall for parts of the Caribbean.
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT SAT SEP 19 2009
FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...
A SURFACE TROUGH ASSOCIATED WITH THE REMNANTS OF FRED IS LOCATED
ABOUT 475 MILES EAST-NORTHEAST OF THE NORTHWESTERN BAHAMAS AND IS
PRODUCING DISORGANIZED SHOWERS AND THUNDERSTORMS. THIS SYSTEM HAS
BECOME LESS ORGANIZED DURING THE DAY AND THE RECONNAISSANCE MISSION
SCHEDULED FOR THIS AFTERNOON HAS BEEN CANCELED. THERE IS A LOW
CHANCE...LESS THAN 30 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES SLOWLY TOWARD THE
WEST-NORTHWEST.
SHOWER AND THUNDERSTORM ACTIVITY HAS DIMINISHED IN ASSOCIATION WITH
A BROAD AREA OF LOW PRESSURE CENTERED ABOUT 1200 MILES EAST OF THE
WINDWARD ISLANDS. HOWEVER...THIS SYSTEM STILL HAS THE POTENTIAL TO
BECOME A TROPICAL DEPRESSION OVER THE NEXT DAY OR TWO AS IT MOVES
TOWARD THE WEST-NORTHWEST AT AROUND 10 MPH. THERE IS A MEDIUM
CHANCE...30 TO 50 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS.
AN AREA OF DISTURBED WEATHER LOCATED A COUPLE HUNDRED MILES
NORTHEAST OF THE CAPE VERDE ISLANDS HAS BECOME LESS ORGANIZED OVER
THE PAST SEVERAL HOURS. DEVELOPMENT OF THIS SYSTEM IS NOT
ANTICIPATED AS IT MOVES TOWARD THE WEST-NORTHWEST AT ABOUT 10 MPH.
THERE IS A LOW CHANCE...LESS THAN 30 PERCENT...OF THIS SYSTEM
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.
ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.
$$
FORECASTER BLAKE
If that ridge establishes too late, it might get sucked in.
Was 1976 - 1977 an El Nino year? After reading about it, it was caused by two Artic Fronts dipping low.
Definitely not good for you folks in the Caribbean, since if I'm not mistaken, you have been suffering a pretty dramatic rainfall deficit throughout the past year.
456, now 98L is back to orange, but the structure is really good
My thoughts are again, consensus is overdoing the strength of 98L and the timing with how long it takes to get strong
This new development to me says 98L will be further south and west again then the consensus shows.
yep, due to El Nino and lack of healthy tropical disturbances. The current forecast through November is showing a greater chance of below normal rains than above/near normal.
I'm not sure what you mean since the intensity guidance only place it between 40-45 mph.
You mean overdoing as in it would get stronger?
Very plausible.
yes, I also think they are overdoing the weakness. To me 98L will only be a weak TS over the next few days, therefore it wont go north
we all know, if this takes longer to develop, it will go further west; if it misses that weakness then its a whole new ballgame
I still think 98L will become a TD by tommorow.
I have a feeling serious downcasting by trolls (rallying up the blog) is about to occur, So im going to head out again.
Getting sucked in
Ok, I understand.
Also I disagree with the NHC putting it back to orange since the chances they give apply to 48 hrs, not entirely on what's happening now. But I'm not complaining because it does not lead us anywhere. They are the experts. Besides it could easily go back red.
yep 98L should get more organized convection tonight, plus with all the convection that has dissipated the environment has become more moist, so expect a healthy 98L tonight
Wishcatsers must be hurtin.
98L
They've just about all left or gone into lurking. I went back and read the posts before recon was canceled. OMG...
New vortices appearing, yes, but still think center is on the southern edge of that.
Have to see what happens, but Fred isn't going to be naked much longer, imo. We'll see if he can do anything with the added moisture.
Can't wait to call this season finished. (I know I have to wait until Dec. 1 to do this officially...)
lol
Yeah...not a big surprise.
Nothing really to look at. Just a wave interacting with a frontal boundary.
Yes, it is trying to increase convection again. How tedious; it'd be best if it degenerate already.
its a low interacting with a frontal boundary
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