Ana and TD 3 take aim at the Lesser Antilles
Tropical Storm Ana was born this morning, when the remnants of Tropical Depression Two made a comeback and organized into the first tropical storm of the 2009 Atlantic hurricane season. Ana is the latest first named storm of the season since Hurricane Andrew got its name on August 17, 1992. The two storms have some similarities, as Andrew formed in the same part of the ocean, and also struggled in its early days with high wind shear and dry air. Let's hope the similarities end there.
Ana is struggling this afternoon. After an modest burst of heavy thunderstorm activity prompted NHC to upgrade Ana to a tropical storm early this morning, Ana has run into strong upper-level winds from the west that are creating high wind shear. This shear was not forecast, and it is not clear how long it will last. The shear has acted to drive dry air into the core of Ana, destroying almost all of Ana's heavy thunderstorms. The low-level center of the storm is now exposed to view, something that often foreshadows the death of a storm. It is possible the shear will destroy Ana, and several models (the GFS and ECMWF) forecast this may be the case. However, the shear forecast calls for shear to drop into the low range, 5 - 10 knots, tonight through Tuesday. If the shear does drop as forecast, Ana should be able to moisten the atmosphere around it sufficiently to protest itself from the dry Saharan air that surrounds it (Figure 1). SSTs are 27°C today, and will increase to 28°C by Sunday. By the time Ana moves into the Bahamas, total ocean heat content rises steeply (Figure 2), and rapid intensification of Ana is possible, if the shear and dry air haven't disrupted the storm. The intensity forecast models, for the most part, predict a steady intensification of Ana to the threshold of hurricane strength five days from now. The HWRF model is on the strong side, predicting a Category 2 hurricane. The GFDL predicts a weak tropical storm five days from now, but that is because the model has Ana passing over the rugged terrain of Hispaniola, something the other models do not predict. In summary, the intensity forecast for Ana has higher than usual uncertainty, and I give equal chances that the storm will be a hurricane--or non-existent--four days from now.
Figure 1. Water vapor image from this morning showing the large area of dry, Saharan air surrounding Ana, and lying to the north of Tropical Depression Three. Image credit: NOAA/SSD
Tropical Depression Three forms, could be Bill later today
QuikSCAT data from this morning and satellite loops revealed that the tropical wave (90L) in the middle Atlantic has finally developed a well developed surface circulation and can be classified as Tropical Depression Three. Recent satellite imagery suggests that TD 3 may already be Tropical Storm Bill. Water vapor imagery (Figure 1) shows that TD 3's center consolidated a few hundred miles south of the dry air of the Saharan Air Layer (SAL). Thus, the storm should not be affected by dry air and dust as much as Ana has been. Ana may also act to moisten the atmosphere in front of TD 3, helping protect the storm from the SAL as it edges farther north over the the three days.
Figure 2. Heat content of the ocean, in kJ per square cm. Oceanic heat content steadily increases for Ana and TD 3 as they approach the Lesser Antilles Islands. Oceanic heat content levels of 90 kJ per square cm are frequently associated with rapid intensification of hurricanes. Image credit: University of Miami.
Wind shear is moderate, 15 knots, but is forecast to fall to 10 - 15 knots on days 2 - 5. Sea Surface Temperatures are about 27.5°C, and will remain in the 27.5 - 28°C range the next five days. The combination of low wind shear and sufficiently warm SSTs should allow TD 3 to intensify steadily, and I expect the storm will be at hurricane strength by Wednesday, when it will be near the northern Lesser Antilles Islands. Most of our reliable intensity models strengthen TD 3 into a hurricane by Wednesday. Oceanic heat content (Figure 2) increases sharply just before the islands, so TD 3 could be intensifying rapidly as it moves through or just north of the Lesser Antilles on Thursday. TD 3 consolidated farther south than expected, so the track models calling for a more northerly path were probably incorrect. In particular, the ECMWF model, which had TD 3 turning sharply northwestward and missing the Lesser Antilles Islands, was probably much too far to the north in this morning's 00Z run. TD 3 will probably pass very close to the northern Lesser Antilles islands on Wednesday and Thursday.
I'll have an update Sunday.
Jeff Masters
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PR HURRICANE STATEMENT NHC...
SITUATION OVERVIEW...
AT THE PRESENT MOMENT...TROPICAL STORM ANA IS NOT WELL ORGANIZED
BUT THE FORECAST IS FOR THE STORM TO SLOWLY INTENSIFY DURING THE
NEXT TWO DAYS AS IT MOVES TOWARDS THE ISLANDS OF THE NORTHEAST
CARIBBEAN. AT THIS TIME...IT IS TOO EARLY TO PROVIDE EXACT
WIND...RAINFALL...AND SURGE FORECAST VALUES FOR SPECIFIC
LOCATIONS. A GENERAL CONCERN SHOULD BE FOR THE POSSIBILITY OF AT
LEAST DAMAGING WINDS AND LOCALIZED FLOODING SOMEWHERE WITHIN
PUERTO RICO AND THE U.S. VIRGIN ISLANDS.
Nope, the tropical near the Florida Keys is an exmaple of where Ana and Bill will be going.
there isnt much room for Ana to go noth as every advisory the track keeps shfiting sotuh.
Excellent point.
It sure looks like it.
yes, and it is beginning to move north of due west (could just be a wobble though)
I used to date a girl from Saint Kitts...which is probably about all of that story any of you wanna hear...
The CFS is still not fixed!
Time of Latest Image: 200908151615
Storm Relative 1km Geostationary Visible Imagery
The current suite of geostationary satellites provides visible imagery during daylight hours at higher resolution than many of the infrared channels. Such imagery is useful, especially when animated, for position estimation and monitoring the degree of convective organization. The native visible imagery has been remapped to a one-km Mercator projection and the digital data has been stretched over its full range - allowing a more esthetically pleasing appearance. The center location is based on the last operational position estimate and the previous 12-hr motion
Also Ana is in the GOM
So if they went yesterday, the models runs are more accurate since Ana has formed? correct?..Im still a newbie in this, so please be patient!
yes and its crazy, that low over the keys is going from nothing to possibly something
No
Time of Latest Image: 20090815 1615UTC
2km Storm Relative IR Imagery with BD Enhancement Curve
2km Storm Relative IR Imagery with BD Enhancement Curve
The same infrared imagery shown in the earth relative framework is displayed in a storm relative framework, with a 2km resolution and enhanced with the "BD Curve" which is useful for directly inferring intensity via the Dvorak Enhanced IR (EIR) technique. Scaling is provided by two lightly hatched circles around the center. The two circles have radii of 1 and 2 degrees latitude, respectively.
Yup.
And it looks like she is having a slight convective comeback (though its still east of the center).
The last thing we want. As you said, the GOM waters have nothing to do but warm, and now they're boiling hot.
dont understimate 70MPH winds, remember Katrina
NOUS42 KNHC 151715
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
0115 PM EDT SAT 15 AUGUST 2009
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 16/1100Z TO 17/1100Z AUGUST 2009
TCPOD NUMBER.....09-079
I. ATLANTIC REQUIREMENTS
1. TROPICAL STORM ANA
FLIGHT ONE -- TEAL 70
A. 16/1800Z,17/0000Z
B. AFXXX 0102A ANA
C. 16/1530Z
D. 15.6N 56.3W
E. 16/1700Z TO 17/0000Z
F. SFC TO 10,000 FT
FLIGHT TWO -- TEAL 71
A. 17/0600Z,17/1200Z
B. AFXXX 0202A ANA
C. 17/0330Z
D. 16.7N 60.0W
E. 17/0500Z TO 17/1200Z
F. SFC TO 10,000 FT
2. OUTLOOK FOR SUCCEEDING DAY: CONTINUE 6-HRLY FIXES.
A G-IV SURVEILLANCE MISSION IS PLANNED FOR 18/0000Z
WITH TAKEOFF AT 17/1730Z. A FOLLOW-ON G-IV MISSION
IS POSSIBLE FOR 18/1200Z WITH TAKEOFF AT 18/0530Z.
3. REMARK: NOAA43 AND THE G-IV WILL FLY FOUR SUCCESSIVE
RESEARCH MISSIONS INTO AND AROUND ANA DEPARTING FROM
TBPB AT 15/2000Z, 16/0800Z, 16/2000Z, AND 17/0800Z.
II. PACIFIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. SUCCEEDING DAY OUTLOOK.....NEGATIVE.
SEF
nope fine for me
Some dropsonde data would clean up the modelsLink
I don't think Ana will upwell waters too much considering her size and intensity. Bill will likely cause some upwelling.
Time of Latest Image: 20090815 1515UTC
Storm Relative 16km Geostationary Water Vapor Imagery
To compliment the 16km storm relative TPW product listed above, water vapor imagery, with a spectral weight near 6.7 um is displayed with the same resolution, projection, and storm relative geometry. Water Vapor imagery is helpful in determining the location of deep convection, indicated by the coldest pixels, relative upper-level moisture content in areas devoid of deep convection, and upper-level atmospheric motions via animation of these images. The imagery can be used to infer favorable and unfavorable regions of environmental forcing (e.g., areas of increased vertical wind shear or atmospheric subsidence).
I was earlier
Is it the cluster of thunderstorms hitting the Florida Keys.
Cool Pic 456
holding hands while cruzin the Atl...lol
Fujiwhara.
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