Disturbance 90L close to tropical depression strength; TD 2 may rise again
A strong tropical wave (90L), with a large circulation and a moderate amount of heavy thunderstorm activity, is a few hundred miles southwest of the Cape Verdes Islands, off the coast of Africa. This morning's QuikSCAT pass shows that 90L has a large circulation, but this circulation is not yet well-formed, as it is elongated along an east-west axis. Satellite imagery from the European METEOSAT satellite show that the heavy thunderstorms associated with 90L are gradually becoming better organized, with some spiral banding evident on the south side of the storm. Satellite intensity estimates from NOAA already put 90L at tropical depression strength with 30 mph winds, but the storm does not yet have a well enough formed circulation to be classified as a depression. Water vapor imagery shows that since 90L is forming several hundred miles south of the dry air of the Saharan Air Layer (SAL), the storm should not be affected by dry air and dust as much as Tropical Depression Two was. However, there is some dry air from the SAL being sucked into the circulation of 90L, and this is retarding its development.
Wind shear is moderate, about 10 - 15 knots, but is forecast to fall to the low range, 5 - 10 knots, later today. Shear is then forecast to remain low for the next five days. Sea Surface Temperatures are about 28°C, and will remain in the 27 - 28°C range the next five days. The combination of low wind shear and sufficiently warm SSTs should allow 90L to develop into a tropical depression by Saturday, and potentially reach hurricane strength by Wednesday. Most of our reliable models strengthen 90L into a hurricane by Wednesday, when the storm is expected to be near the northern Lesser Antilles Islands. One important outlier is the ECMWF model, which has 90L passing to the north of the islands, and eventually recurving out to sea east of Bermuda. The ECMWF was by far the most reliable model for forecasting hurricane tracks last year. However, all of our models are pretty unreliable going out 5 days in advance for systems that have yet to reach tropical depression strength. Once 90L becomes a tropical depression and develops a well-formed circulation, the models will have a better handle on forecasting where it will go.
Figure 1. The remnants of Tropical Depression Two (left side of image) and tropical wave 90L (right side of image).
Tropical Depression Two may come back
Tropical Depression Two died yesterday, but may rise again. Satellite loops of the remnants of the storm show that heavy thunderstorms are again attempting a comeback near the axis of what is now a tropical wave. However, dry air continues to interfere with the development of the thunderstorm activity, and moderately high wind shear of 15 - 20 knots is also inhibiting the process. Wind shear over the remnants of TD 2 is expected to remain in the moderate range, 10 - 20 knots, over the next four days. Sea Surface Temperatures (SSTs) are 27°C, but will warm to 28°C two days from now. There is plenty of dry, stable air from the Saharan Air Layer (SAL) to the north and west that will continue to cause the storm problems. The relatively cool SSTs and dry air mean that any re-development of the storm will be slow to occur. NHC has given the system a medium (30 - 50% chance) of becoming a tropical depression again by Sunday morning. Only one reliable model, the NOGAPS, is predicting regeneration of TD 2. The NOAA Hurricane Hunters are flying research missions into the remnants of TD 2 today and Saturday.
I'll have an update Saturday morning, or earlier, if significant developments occur.
Jeff Masters
Reader Comments
Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 | 81 | 82 | 83 | 84 | 85 | 86 | 87 | 88 | 89 | 90 | 91 | 92 | 93 | 94 | 95 | 96 | 97 | 98 | 99 | 100 | 101 | 102 | 103 | 104 | 105 | 106 | 107 | 108 | 109 | 110 | 111 | 112 | 113 | 114 — Blog Index
But remember your image that you showed with the VTMAX it showed winds up to 30 knots!
Forecast says it'll begin on a weakening trend now.
I'm still in, cause it's Ana!
THE CLARITY OF THE EYE IN INFRARED IMAGERY HAS VARIED OVER THE PAST
FEW HOURS. DVORAK T-NUMBERS WERE 5.5 FROM TAFB AND 5.0 FROM SAB
AT 0600 UTC...WHILE THE 3-HOUR AVERAGE UW-CIMSS ADT VALUES REMAIN
AROUND 6.0. THE INITIAL INTENSITY IS KEPT AT 100 KT AS A BLEND OF
THESE ESTIMATES.
First time I've seen them mention the ADT... perhaps I've missed it in times past.
WTNT22 KNHC 150836
TCMAT2
TROPICAL STORM ANA FORECAST/ADVISORY NUMBER 13
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022009
0900 UTC SAT AUG 15 2009
INTERESTS IN THE LEEWARD ISLANDS SHOULD MONITOR THE
PROGRESS OF TROPICAL STORM ANA. A TROPICAL STORM WATCH MAY BE
REQUIRED FOR PORTIONS OF THE LEEWARD ISLANDS LATER TODAY.
TROPICAL STORM CENTER LOCATED NEAR 14.6N 46.8W AT 15/0900Z
POSITION ACCURATE WITHIN 20 NM
PRESENT MOVEMENT TOWARD THE WEST OR 270 DEGREES AT 14 KT
ESTIMATED MINIMUM CENTRAL PRESSURE 1005 MB
MAX SUSTAINED WINDS 35 KT WITH GUSTS TO 45 KT.
34 KT....... 60NE 0SE 0SW 60NW.
There we go.
1,0,0.
WTNT32 KNHC 150836
TCPAT2
BULLETIN
TROPICAL STORM ANA ADVISORY NUMBER 13
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022009
500 AM AST SAT AUG 15 2009
...ANA FORMS IN THE TROPICAL ATLANTIC OCEAN...
INTERESTS IN THE LEEWARD ISLANDS SHOULD MONITOR THE PROGRESS OF
TROPICAL STORM ANA. A TROPICAL STORM WATCH MAY BE REQUIRED FOR
PORTIONS OF THE LEEWARD ISLANDS LATER TODAY.
FOR STORM INFORMATION SPECIFIC TO YOUR AREA IN THE UNITED
STATES...INCLUDING POSSIBLE INLAND WATCHES AND WARNINGS...PLEASE
MONITOR PRODUCTS ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE
FORECAST OFFICE. FOR STORM INFORMATION SPECIFIC TO YOUR AREA
OUTSIDE OF THE UNITED STATES...PLEASE MONITOR PRODUCTS ISSUED
BY YOUR NATIONAL METEOROLOGICAL SERVICE.
AT 500 AM AST...0900 UTC...THE CENTER OF TROPICAL STORM ANA WAS
LOCATED NEAR LATITUDE 14.6 NORTH...LONGITUDE 46.8 WEST OR ABOUT 1010
MILES...1630 KM...EAST OF THE LEEWARD ISLANDS.
ANA IS MOVING TOWARD THE WEST NEAR 16 MPH...26 KM/HR...AND THIS
GENERAL MOTION IS EXPECTED TO CONTINUE FOR THE NEXT COUPLE OF DAYS
WITH AN INCREASE IN FORWARD SPEED. ON THIS FORECAST TRACK ANA COULD
BE APPROACHING THE LEEWARD ISLANDS ON MONDAY.
MAXIMUM SUSTAINED WINDS ARE NEAR 40 MPH...65 KM/HR...WITH HIGHER
GUSTS. SLOW STRENGTHENING IS FORECAST FOR NEXT 48 HOURS.
TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 70 MILES...110 KM
FROM THE CENTER.
THE ESTIMATED MINIMUM CENTRAL PRESSURE BASED ON DATA FROM NOAA BUOY
41041 IS 1005 MB...29.68 INCHES.
...SUMMARY OF 500 AM AST INFORMATION...
LOCATION...14.6N 46.8W
MAXIMUM SUSTAINED WINDS...40 MPH
PRESENT MOVEMENT...WEST OR 270 DEGREES AT 16 MPH
MINIMUM CENTRAL PRESSURE...1005 MB
THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT
1100 AM AST.
$$
FORECASTER BLAKE
WTNT32 KNHC 150836
TCPAT2
BULLETIN
TROPICAL STORM ANA ADVISORY NUMBER 13
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022009
500 AM AST SAT AUG 15 2009
...ANA FORMS IN THE TROPICAL ATLANTIC OCEAN...
INTERESTS IN THE LEEWARD ISLANDS SHOULD MONITOR THE PROGRESS OF
TROPICAL STORM ANA. A TROPICAL STORM WATCH MAY BE REQUIRED FOR
PORTIONS OF THE LEEWARD ISLANDS LATER TODAY.
FOR STORM INFORMATION SPECIFIC TO YOUR AREA IN THE UNITED
STATES...INCLUDING POSSIBLE INLAND WATCHES AND WARNINGS...PLEASE
MONITOR PRODUCTS ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE
FORECAST OFFICE. FOR STORM INFORMATION SPECIFIC TO YOUR AREA
OUTSIDE OF THE UNITED STATES...PLEASE MONITOR PRODUCTS ISSUED
BY YOUR NATIONAL METEOROLOGICAL SERVICE.
AT 500 AM AST...0900 UTC...THE CENTER OF TROPICAL STORM ANA WAS
LOCATED NEAR LATITUDE 14.6 NORTH...LONGITUDE 46.8 WEST OR ABOUT 1010
MILES...1630 KM...EAST OF THE LEEWARD ISLANDS.
ANA IS MOVING TOWARD THE WEST NEAR 16 MPH...26 KM/HR...AND THIS
GENERAL MOTION IS EXPECTED TO CONTINUE FOR THE NEXT COUPLE OF DAYS
WITH AN INCREASE IN FORWARD SPEED. ON THIS FORECAST TRACK ANA COULD
BE APPROACHING THE LEEWARD ISLANDS ON MONDAY.
MAXIMUM SUSTAINED WINDS ARE NEAR 40 MPH...65 KM/HR...WITH HIGHER
GUSTS. SLOW STRENGTHENING IS FORECAST FOR NEXT 48 HOURS.
TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 70 MILES...110 KM
FROM THE CENTER.
THE ESTIMATED MINIMUM CENTRAL PRESSURE BASED ON DATA FROM NOAA BUOY
41041 IS 1005 MB...29.68 INCHES.
...SUMMARY OF 500 AM AST INFORMATION...
LOCATION...14.6N 46.8W
MAXIMUM SUSTAINED WINDS...40 MPH
PRESENT MOVEMENT...WEST OR 270 DEGREES AT 16 MPH
MINIMUM CENTRAL PRESSURE...1005 MB
THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT
1100 AM AST.
$$
FORECASTER BLAKE
Put a jackass on my avatar...lol...
CPHC issuing advisories on ANA
Last NHC advisory issued on ANA
Error from NHC
That would be me.. I go to the University of Miami
GENERAL MOTION IS EXPECTED TO CONTINUE FOR THE NEXT COUPLE OF DAYS
WITH AN INCREASE IN FORWARD SPEED.
TCDAT2
TROPICAL STORM ANA DISCUSSION NUMBER 13
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022009
500 AM AST SAT AUG 15 2009
SATELLITE IMAGES INDICATE THAT THE TROPICAL DEPRESSION HAS CONTINUED
TO BECOME BETTER ORGANIZED AND IS NOW UPGRADED TO TROPICAL STORM
ANA. THE STORM IS DISPLAYING IMPROVED BANDING IN THE WESTERN
SEMICIRCLE ALONG WITH A BALL OF CONVECTION NEAR THE CENTER. NOAA
BUOY 41041 REPORTED A MINIMUM PRESSURE OF ABOUT 1005 MB AS THE
DEPRESSION PASSED VERY NEAR THE BUOY. THE INITIAL INTENSITY IS
RAISED TO 35 KT FOR THIS ADVISORY IN AGREEMENT WITH DVORAK
INTENSITY ESTIMATES FROM SAB AND TAFB.
THE INITIAL MOTION ESTIMATE IS 270/14. THE GLOBAL MODELS ARE IN
AGREEMENT THAT A DEEP-LAYER RIDGE WILL STRENGTHEN NORTH OF THE
TROPICAL CYCLONE OVER THE NEXT DAY OR SO. THIS PATTERN FAVORS THE
TRACK OF ANA GRADUALLY BENDING FROM A WEST TO A WEST-NORTHWEST
DIRECTION WITH AN INCREASE IN FORWARD SPEED. THE ONLY SIGNIFICANT
OUTLIERS TO THIS TRACK ARE THE GFDL AND GFS...WHICH BOTH WEAKEN THE
SYSTEM RATHER QUICKLY...LEADING TO A MORE WESTWARD TRACK OF THE
CYCLONE. IN A FEW DAYS...SOME OF THE MODELS...SUCH AS THE GFS...
SHOW A WEAKNESS IN THE RIDGE OVER THE WESTERN ATLANTIC THAT COULD
ALLOW THE CYCLONE TO GAIN A LITTLE MORE LATITUDE. THIS WEAKNESS
APPEARS TO BE CAUSED BY THE MID- TO UPPER-LEVEL LOW CURRENTLY NEAR
25N 65W. HOWEVER...THE MAJORITY OF THE GUIDANCE SHOWS THE MID- TO
UPPER-LEVEL LOW MOVING WEST-SOUTHWESTWARD WITH MINIMAL INFLUENCE ON
THE STRENGTH OF THE RIDGE. GENERALLY...THE MODELS THAT HOLD ONTO
ANA ARE IN GOOD AGREEMENT THROUGHOUT THE FORECAST PERIOD. THE NHC
TRACK FORECAST IS SHIFTED TOWARD THE SOUTHWEST FOR THIS ADVISORY...
BUT NOT AS FAR AS THE MODEL CONSENSUS.
THE 0000 UTC GLOBAL MODELS GENERALLY FORECAST A MORE CONDUCIVE
ENVIRONMENT FOR STRENGTHENING THAN PREVIOUS CYCLES...SHOWING A
WEAKER MID-OCEANIC TROUGH AFFECTING THE SYSTEM. IN PARTICULAR...THE
UKMET AND NOGAPS BUILD UPPER-RIDGING NEAR THE CYCLONE WITH LIGHT
SHEAR THROUGH THE PERIOD. HOWEVER...THE ECMWF SHOWS SOME WESTERLY
SHEAR DEVELOPING IN ABOUT A DAY...BUT EVEN THAT MODEL HAS LIGHTER
SHEAR CONDITIONS IN A FEW DAYS. THE INTENSITY GUIDANCE RUNS THE
FULL SPECTRUM THIS MORNING...WITH THE GFDL DISSIPATING THE
SYSTEM...WHILE THE HWRF SHOWS A CATEGORY TWO HURRICANE BY THE END
OF THE FORECAST PERIOD. GIVEN THE UNCERTAINTY IN THE UPPER-LEVEL
ENVIRONMENT LATER IN THE FORECAST PERIOD...THE OFFICIAL INTENSITY
FORECAST IS INCREASED CONSERVATIVELY...IN BEST AGREEMENT WITH THE
SHIPS MODEL BUT BELOW THE INTENSITY CONSENSUS.
A TROPICAL STORM WATCH MAY BE REQUIRED FOR PORTIONS OF THE LEEWARD
ISLANDS LATER TODAY.
FORECAST POSITIONS AND MAX WINDS
INITIAL 15/0900Z 14.6N 46.8W 35 KT
12HR VT 15/1800Z 14.7N 49.4W 40 KT
24HR VT 16/0600Z 15.3N 52.7W 45 KT
36HR VT 16/1800Z 16.1N 56.4W 45 KT
48HR VT 17/0600Z 17.0N 60.0W 50 KT
72HR VT 18/0600Z 19.5N 67.0W 55 KT
96HR VT 19/0600Z 22.5N 73.0W 60 KT
120HR VT 20/0600Z 26.0N 78.5W 60 KT
$$
FORECASTER BLAKE
Near a hurricane towards the end of the forecast.
Mornin' Ike.
Which would generally indicate strong high pressure... not good for avoiding a U.S. strike.. This looks like it will be someone's problem come next week, the question now becomes whom's?
Oh wow that's a good school! Are you planning to go to grad school?
It has it hitting as a 70 mph right around where I live. Sounds like fun.
I am, don't know if I'll be able to afford Miami for grad school though, might go to FSU for grad. Miami is 35.5k per year for tuition, luckily I got a scholarship but It's only good for 3 more years, which is enough for my Bachelor's and year towards my Master's.
There are you happy. LOL Wonder how it'll be like when more people wake up?
PS: in all seriousness lets hope for the best
Nah, I wouldn't do that, I would think of something better. lol
Morning....
Finally.....after 76 days......
1-0-0
Way to go your speciality will most likely be Tropical Weather right?
They admit this is below the intensity guidelines, which with reference to the NHC intensity forecast, would mean they could expect a hurricane around 96 hours time, ish. Somewhere over the Bahamas and Cuba.
But I have a question...does anyone forsee any potential areas in which Ana may potentially go through a rapid intensification stage?
I mean, I've seen over the years NHC forecasting a newly developed storm rather conservatively, only to have it bomb out somewhere along it's track and thus become much stronger than they or the models forecasted.
No, I am not saying this will happen, nor do I wish it to. Rather I am just wondering if any more experienced members here have an opinion or potential answer to my question.
Puny aint she?
Weakening Flag : ON
Cloud tops have warmed a bit in the past half hour, about 2 degrees C. However, the Dvorak #'s still indicate a moderate TS, and is still well ahead of the NHC's conservative intensity estimates.
the Bahamas and around the SE Florida have very high THCP and SST waters. I'm afraid it wouldn't be out of the question for it to bomb around there. It's certainly happened before.
Who knows whether it would, depends on shear and other factors. Long time out, and the track may yet change. Anything after 3 days is always difficult
Edit: oh, but one thing: It'll be moving on a good clip around there, it won't have that much time over the really hot waters. That can only be good.
Probably just Severe Weather in general, I also have heavy interest in Tornadoes and Severe Thunderstorms. Definitely Tropical Weather as well, though!
OMG Me too! :) I would love to do that...Im a fourth year student UC Davis! :)
remember models are meant to be used as guidance only and do not depict final outcome for any one event things can and will change
now would be a good time to go over hurr. plans and begin first steps of gettin ready more so for our leeward island friends at the moment
That place, especially after last year, really does not need anymore.
WTNT42 KNHC 150840
TCDAT2
TROPICAL STORM ANA DISCUSSION NUMBER 13
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022009
500 AM AST SAT AUG 15 2009
SATELLITE IMAGES INDICATE THAT THE TROPICAL DEPRESSION HAS CONTINUED
TO BECOME BETTER ORGANIZED AND IS NOW UPGRADED TO TROPICAL STORM
ANA. THE STORM IS DISPLAYING IMPROVED BANDING IN THE WESTERN
SEMICIRCLE ALONG WITH A BALL OF CONVECTION NEAR THE CENTER. NOAA
BUOY 41041 REPORTED A MINIMUM PRESSURE OF ABOUT 1005 MB AS THE
DEPRESSION PASSED VERY NEAR THE BUOY. THE INITIAL INTENSITY IS
RAISED TO 35 KT FOR THIS ADVISORY IN AGREEMENT WITH DVORAK
INTENSITY ESTIMATES FROM SAB AND TAFB.
I agree with that last statement if that's what they are solely looking at.
Nice! You're majoring in meteorology, then? What's it like to study out there in Cali?
Thanks Cotillion. Yes, it definitely has happened before, I can remember many storms in which it has occurred. Hopefully the speed forecast as you mentioned does not allow this to occur.
Speaking of TCHP, do you know where I can possibly have a look at these data maps? I used to get TCHP data off of here , but it has not updated since last May. Is there another public source online at which one can view such data?
Well Atmospheric Science...yes....It's really nice to study out in Cali...the faculty are nice...:) Im really hoping to go to U of OK...for grad school or U of IL Urbania Champagne!
Link
Thanks!
I recently got a new computer, so I lost all my tropical links. I was not aware of that overlay or the name switch.
Forgot to mention.. It's easiest to click on the active storm, and then you'll see the overlay options at the top of the screen. Ocean Heat Content is on the second row, next to the "Ocean:" overlays. It reads "OHC (RSMAS)" where RSMAS is Rosenstiel School of Marine and Atmospherics Science (University of Miami)
No worries, It's all new this year! CIMSS completely overhauled their website in the "off-season".
I considered U of OK for awhile, but they just were too expensive for out of state, and didn't offer many scholarships as compared to University of Miami. Plus, I live in Florida so it's much closer, the NHC is down there, it has beaches.. Etc.. :)
So what do you all focus on, then? No specific form of Weather?
Viewing: 4051 - 4101
Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 | 81 | 82 | 83 | 84 | 85 | 86 | 87 | 88 | 89 | 90 | 91 | 92 | 93 | 94 | 95 | 96 | 97 | 98 | 99 | 100 | 101 | 102 | 103 | 104 | 105 | 106 | 107 | 108 | 109 | 110 | 111 | 112 | 113 | 114 — Blog Index