Ana, Bill,--and Claudette?
After one of the slowest starts to hurricane season in the past twenty years, the hurricane season of 2009 has exploded with activity over the past 48 hours. This morning, Tropical Depression Four joined Ana and Bill in the Atlantic, and appears poised to become Tropical Storm Claudette later today. Indeed, this may already be Claudette, as morning's QuickSCAT pass showed top winds of 45 mph. NEXRAD radar animations out of Tallahassee, FL, show a small but well-organized tropical cyclone with plenty of heavy thunderstorm activity, and improving low-level spiral banding. Satellite loops show an area of intense thunderstorms with cold cloud tops expanding near the storm's center.
Figure 1. Current long-range radar out of Tallahassee, FL.
It's pretty amazing (and a little unnerving) how quickly this storm sprang up. TD 4 developed literally overnight, and has the potential to be a strong tropical storm by the time it makes landfall tonight along the Florida Peninsula. TD 4 reminds me of 2007's Hurricane Humberto, which became a hurricane just 24 hours after first appearing as a tropical depression. I don't think TD 4 has time to reach hurricane strength, since wind shear as diagnosed by the SHIPS model was moderate, 10 - 15 knots, but it does have time to strengthen into a 50 - 60 mph tropical storm before landfall. Given that the storm is so small, storm surge flooding should not exceed 3 -5 feet, and will not be the major hazard from TD 4; inland flooding from heavy rain of 3 - 6 inches is likely to be the main threat from the storm.
Tropical Storm Ana continues to struggle
Tropical Storm Ana continues to struggle. Dry air continues to plague the storm, thanks to the large area of Saharan air the storm is embedded in. Ana's heavy thunderstorms are limited to just one small spot near the center. Wind shear appears to have lessened some, though, since yesterday. Thunderstorms were not able to form at all near the center yesterday, since strong wind shear tends to blow a storm's heavy thunderstorms to one side of the storm, exposing the low-level center to view. With heavy thunderstorms building near the center this morning, shear appears to be less of a problem for the storm. Top winds seen by this morning's QuikSCAT pass were about 35 mph. The outer rain showers from Ana should appear on radar out of Martinique today.
Shear is low (5 - 10 knots), and is forecast to remain low for the next two days. SSTs are warm, 28°C, and will warm further over the next two days. However, there is so much dry air around Ana that significant strengthening appears unlikely. Nearly all of the models predict Ana will dissipate sometime in the next three days, though the HWRF and GFDL predict that this will happen because Ana will move over the rugged terrain of Hispaniola. Ana is likely not strong enough to survive an encounter with the big island that the Dominican Republic and Haiti share. At this time, it does not appear that Ana will be moist enough to cause a major flooding disaster on Hispaniola.
Figure 2. Water vapor image from this morning showing the large area of dry, Saharan air surrounding Ana, and lying to the northwest of Tropical Storm Bill. Image credit: NOAA/SSD
Tropical Storm Bill gathers strength
Tropical Storm Bill is gathering strength in the middle Atlantic Ocean, and appears poised to become a powerful Cape Verdes-type hurricane later this week. QuikSCAT data from this morning shows a large circulation with top winds of 35 - 40 mph. Water vapor imagery (Figure 2) shows that there is some dry air to the northwest of Bill, and this dry air is being drawn into Bill's center, slowing intensification. It will likely take another day before Bill can moisten the atmosphere enough to ward off the dry air, and allow more significant intensification.
Wind shear is low, 5 - 10 knots, and is forecast to be in the low to moderate range, 5 - 15 knots, for the next five days. Sea Surface Temperatures are about 27.5°C, and will remain in the 27.5 - 28°C range the next four days, then warm substantially as the storm nears the Lesser Antilles Islands. The combination of low wind shear and sufficiently warm SSTs should allow Bill to intensify steadily to hurricane strength by Wednesday.
The big news is that our most reliable computer model from last year--the ECMWF model--appears to have made the right call yesterday, forecasting that a major trough of low pressure would develop along the U.S. East Coast, turning Bill more to the north. All of the other models--with the notable exception of the UKMET model--have now jumped on the ECMWF bandwagon, forecasting that Bill will pass well north of the Lesser Antilles Islands. The UKMET has Bill hitting the islands, but is being discounted since it is an outlier. It currently appears that the trough approaching the U.S. East Coast will be strong enough to recurve Bill before it reaches the U.S., though it is too early to be confident of this. Several of the longer range models show Bill passing near Bermuda or Nova Scotia, Canada.
I'll have an update later today.
Jeff Masters
Reader Comments
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A few garbage cans too! She'll probably even bring down a few trees.
Probably wont relocate it has great low level circulation. But, as I said, I think it may *move* in that direction.. NNE-NE very slowy before tracking WNW is my guess.
I completely agree! Appalachicola and Tallahassee FL will bear the brunt of Claudette. She will mostly be a rainmaker.
looks like its gonna be a stormy monday/tuesday, nothing major
good afternoon to you friend
behind Bill. next invest
WTNT44 KNHC 161749
TCDAT4
TROPICAL STORM CLAUDETTE SPECIAL DISCUSSION NUMBER 3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL042009
200 PM EDT SUN AUG 16 2009
DATA FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INDICATE
THAT CLAUDETTE HAS CONTINUED TO INTENSIFY. BASED ON A MAXIMUM
FLIGHT LEVEL WIND 54 KT MEASURED AT AN ELEVATION OF ABOUT 2500
FEET...THE INITIAL INTENSITY IS RAISED TO 45 KT. THE 12-HOUR
FORECAST INTENSITY IS ALSO ADJUSTED UPWARD TO ACCOUNT FOR THE
POSSIBILITY FOR ADDITONAL STRENGTHENING PRIOR TO LANDFALL. THE WIND
RADII HAVE ALSO BEEN EXPANDED BASED ON THE AIRCRAFT DATA AND THE
CHANGE IN THE INTENSITY FORECAST.
FORECAST POSITIONS AND MAX WINDS
INITIAL 16/1800Z 29.1N 85.1W 45 KT
12HR VT 17/0000Z 30.2N 85.8W 55 KT
24HR VT 17/1200Z 32.1N 87.1W 35 KT...INLAND
36HR VT 18/0000Z 34.0N 88.2W 20 KT...DISSIPATING INLAND
48HR VT 18/1200Z...DISSIPATED
$$
FORECASTER BRENNAN/ROBERTS
Yeh - I got the compass bearing wrong on my software - I was trying to follow the loop, as #3 was moving over Florida, and therefore Bill could slot in that new Tropical Cyclone size gap.
lots of dry air on that bill :/
Looks like an upper level low.
Right now neither Pensacola nor Mobile are in the warning areas nor the forecast cone. This is subject to change obviously, but it appears you should, I repeat should, be okay. Again, always subject to change, but Claudette getting very close to land now.
That's 30 miles SSE of me.
Keep in mind that the worst affects of a tropical storm after storm surge are tornado's and flooding. The lower tier of southern states have had a lot of rainfall already (In Jax, we've averaged 5 inches a week for a month now).
(~ 55.2 mph)
Claudette.
You could lose power.
When a tropical storm/hurricane watch and/or warning is issued for any area, advisories are issued every 3 hours. Otherwise, they are issued every 6 hours.
Very unlikely you will get the NE quad....the one that would push water in. But watch for the possibility.
On the west side, should you even get that, your water levels should fall a little, and not rise at all (until it passes; then back to normal).
Get out then.
cimss shows there is some 850mb vorticity with it.
She should move on through. I like a little right of the NHC black line..Franklin or Gulf counties for a landfall.
And I've got trees all around the area I live in...out in the country.
97L brought strong winds very heavy rain near-zero highway visibility and good surf to south coast of puerto rico. thinking thats about right with ana, only stronger, if she gets nearer and to our south
IKE you look at the inland TS warnings? Is it just me or do you think they are a bit too far west as far as alabama is concerned with most of its convection being so far to the east of its center.
beautiful pic! :D
Well, then you are more likely to lose power then. Those trees can create havoc.
I don't have the knowledge or experience of many people here, but I've been tracking Hurricanes since I was a kid so its been a hobby of mine for a long, long time. I'll just post my summary...
1) Ana is surviving. She relocated her COC to the NW, or at least to me it seemed like that, and is moving WNW now, maybe even NW. The thing is the track will shift north, either over PR or ABOVE it. At the moment she's weak, so only rain and some winds I expect.
2) Bill is the bane of my existance. I know what the models say, but as I posted previously Bill wants to pull a Dean or worst case scenario for us a Georges. The High Pressure to the north will just not let it turn that much to the North anytime soon and I assure you the track will shift to the south soon. I don't think we will receive a direct impact... but that's only hope. Nature decides what happens.Hope you help your friend!
Good Panama City Beach webcam.
Transmitted: 16th day of the month at 17:50Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 304)
Tropical Depression: Number 4 (flight originating in the North Atlantic basin)
Mission Number: 1
Observation Number: 05
A. Time of Center Fix: 16th day of the month at 17:33:00Z
B. Center Fix Coordinates: 29°08'N 85°05'W (29.1333N 85.0833W)
B. Center Fix Location: 80 miles (129 km) to the SSE (154°) from Panama City, FL, USA.
C. Minimum Height at Standard Level: 753m (2,470ft) at 925mb
D. Estimated (by SFMR or visually) Maximum Surface Wind: 57kts (~ 65.6mph)
E. Location of the Estimated Maximum Surface Wind: 12 nautical miles (14 statute miles) to the E (94°) of center fix
F. Maximum Flight Level Wind Inbound: From 145° at 45kts (From the SE at ~ 51.8mph)
G. Location of Maximum Flight Level Wind Inbound: 55 nautical miles (63 statute miles) to the E (84°) of center fix
H. Minimum Sea Level Pressure: 1008mb (29.77 inHg) - Extrapolated
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 19°C (66°F) at a pressure alt. of 762m (2,500ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 22°C (72°F) at a pressure alt. of 764m (2,507ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 9°C (48°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Not Available
M. Eye Shape: Not Available
N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Level: 925mb (If this vortex is from mid 1990's or earlier 925mb might be incorrect. See note.)
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 2 nautical miles
Remarks Section:
Maximum Flight Level Wind: 54kts (~ 62.1mph) in the northeast quadrant at 16:45:00Z
Sea Level Pressure Extrapolation From: 925mb
Displacement of Sfc. Center From Flt. Lvl. Center: Surface center is 6 nautical miles to the W (276°) from the flight level center
Viewing: 1151 - 1201
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