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
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 — Blog Index
16/1145 UTC 28.2N 84.2W T2.0/2.0 04L
16/1145 UTC 12.2N 37.7W T3.0/3.0 BILL
16/1145 UTC 14.5N 54.9W T1.5/2.0 ANA
Active Tropics: TD 4; TS Ana; TS Bill
this high is essentially the key player in bill and anna's track. the models are all currently way off with the intensity and oreintation and movement of this high. Bill and Anna may never see the trough 4-5 days out and may very well make landfall in south Florida if the high keeps digging in.
Florida Residents Stay Tuned to the Tropics .....
The ASCAT showed west winds, albeit not predominant in the southern semi circle. It is evident in the shortwave imagery.
What do you make of the quikscat pass of Ana ?
Indians ask their new chief whether the winter will be cold or mild. Since the young chief never learned the ways of his ancestors, he tells them to collect firewood, then goes off and calls the National Weather Service.
“Will the winter be bad?”, he asks.
“Looks like it.”, is the answer.
So the chief tells his people to gather more firewood. A week later he calls again. “Are you positive the winter will be very cold?”
“Absolutely.”
The chief tells his people to gather even more firewood, then calls the NWS again: “Are you sure?”
“I’m telling you, it’s going to be the coldest winter on record.”
“How do you know?”
“Because the Indians are gathering firewood like crazy!”
Morning. It would appear there is a burst of convection slightly to the North of the 8:00 PM position. Would you know if a system as weak as Ana could reform a COC. Each run shows the convection to be bigger and slightly North. In your opinion, could this significantly change to forecast track??
Looks like 91 has surprised us. I expect it to hit between PCB and Destin at about 50 mph sustained winds. Everyone on the Panhandle needs to make preparations. Bring in anything that may blow, etc.... you know the drill!
4-Hour Radar Loop
I'm going to try to catch a quick nap, lol, I'll be back! I don't know about many of you all, but I've just got a bad feeling this could intensify to be a bit stronger than residents of the Panhandle are expecting...
I dont believe Ana is a tropical storm, just based on satellite imagery but the QS confirmed it.
Looks like an open wave to me
A cluster of thunderstorms to me haha.
WHXX01 KWBC 161232
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1232 UTC SUN AUG 16 2009
DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.
ATLANTIC OBJECTIVE AIDS FOR
TROPICAL CYCLONE FOUR (AL042009) 20090816 1200 UTC
...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
090816 1200 090817 0000 090817 1200 090818 0000
LAT LON LAT LON LAT LON LAT LON
BAMS 28.2N 84.2W 29.7N 85.9W 31.1N 87.6W 32.5N 88.9W
BAMD 28.2N 84.2W 29.3N 85.5W 30.2N 86.6W 30.9N 87.4W
BAMM 28.2N 84.2W 29.5N 85.7W 30.6N 87.2W 31.6N 88.3W
LBAR 28.2N 84.2W 29.8N 85.6W 31.5N 86.9W 33.4N 87.6W
SHIP 30KTS 35KTS 39KTS 45KTS
DSHP 30KTS 35KTS 29KTS 27KTS
...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
090818 1200 090819 1200 090820 1200 090821 1200
LAT LON LAT LON LAT LON LAT LON
BAMS 33.6N 90.1W 36.7N 90.1W 41.9N 84.0W 46.7N 78.2W
BAMD 31.5N 88.1W 33.4N 87.9W 36.6N 83.2W 40.8N 75.4W
BAMM 32.6N 89.2W 35.3N 88.6W 39.6N 81.8W 43.1N 71.8W
LBAR 35.5N 87.3W 38.7N 81.7W 38.2N 73.0W 35.4N 71.6W
SHIP 47KTS 46KTS 40KTS 37KTS
DSHP 27KTS 28KTS 30KTS 30KTS
...INITIAL CONDITIONS...
LATCUR = 28.2N LONCUR = 84.2W DIRCUR = 325DEG SPDCUR = 12KT
LATM12 = 26.3N LONM12 = 83.1W DIRM12 = 323DEG SPDM12 = 12KT
LATM24 = 24.2N LONM24 = 80.2W
WNDCUR = 30KT RMAXWD = 30NM WNDM12 = 25KT
CENPRS = 1011MB OUTPRS = 1015MB OUTRAD = 90NM SDEPTH = M
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM
$$
NNNN
you can find the shortwave imagery here:
you can microwave data here
Good Morning. I see you are up early. I just posed a question to stormwatcherCI, however, I would like your opinion if you don't mind. It appears on the NOAA runs that Ana is having a burst of convection slightly North of the 8:00 pm position. Could she be trying to form a new COC and how could this effect her forecast position.
and that makes it all well? What about the leewards and Bermuda, and not to mention the Bahamas.
Oh, now you've done it.
You wrote her off once, she came back, you're writing her off again.. but most of all. You compared her to another female.
Now she'll survive, just to spite you!
The wave train keeps coming.
I haven't had time to look at that area closely but pressure at buoy 42057 just S of us is 1012 mb, not very low. I have to head out now for my golf game but will check in this afternoon.
Have a good day all
WHXX01 KWBC 161236
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1236 UTC SUN AUG 16 2009
DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.
ATLANTIC OBJECTIVE AIDS FOR
TROPICAL CYCLONE ANA (AL022009) 20090816 1200 UTC
...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
090816 1200 090817 0000 090817 1200 090818 0000
LAT LON LAT LON LAT LON LAT LON
BAMS 14.6N 54.8W 15.9N 59.0W 17.6N 63.5W 19.5N 67.5W
BAMD 14.6N 54.8W 15.3N 58.0W 16.0N 61.6W 16.9N 65.3W
BAMM 14.6N 54.8W 15.3N 58.4W 16.0N 62.4W 17.0N 66.3W
LBAR 14.6N 54.8W 15.4N 58.3W 16.4N 62.1W 17.4N 65.9W
SHIP 35KTS 35KTS 39KTS 45KTS
DSHP 35KTS 35KTS 39KTS 45KTS
...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
090818 1200 090819 1200 090820 1200 090821 1200
LAT LON LAT LON LAT LON LAT LON
BAMS 21.2N 71.6W 24.3N 77.4W 26.4N 80.8W 27.5N 83.1W
BAMD 17.7N 69.0W 19.4N 75.5W 20.5N 80.5W 21.3N 84.7W
BAMM 17.8N 70.3W 19.4N 77.7W 20.7N 83.8W 22.0N 88.7W
LBAR 18.2N 69.8W 19.9N 76.3W 21.4N 80.3W 28.9N 79.1W
SHIP 51KTS 59KTS 70KTS 79KTS
DSHP 51KTS 47KTS 46KTS 55KTS
...INITIAL CONDITIONS...
LATCUR = 14.6N LONCUR = 54.8W DIRCUR = 275DEG SPDCUR = 18KT
LATM12 = 14.4N LONM12 = 50.7W DIRM12 = 272DEG SPDM12 = 18KT
LATM24 = 14.3N LONM24 = 47.6W
WNDCUR = 35KT RMAXWD = 30NM WNDM12 = 35KT
CENPRS = 1005MB OUTPRS = 1010MB OUTRAD = 150NM SDEPTH = M
RD34NE = 45NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM
$$
NNNN
Still at 35kts, oddly.
ANALOGS TO THE 5 DAY MEAN OBSERVED PATTERN CENTERED 3 DAYS AGO (D-3)
FOR THE REGION FROM 20N TO 70N LATITUDE AND 175E TO 60W LONGITUDE
INCLUDE THE 5 DAY PERIODS CENTERED ON THE FOLLOWING DATES:
19550727 - 19910825 - 19780813 - 19520825 - 19880811
I take it back, every word LOL
It should not affect her forecast that much since she is wthin 48 hrs of the islands and there is only so much distance in the islands chain.
Also, Ana can produce sporadic burst of convection but until she can maintain and sustain it, i doubt she will amount to much.
I just can't believe how quickly it is building and intensifying its thunderstorms
Yup. Welcome to the hot, shallow waters of the gomex.
The faster it moves, the better off our panhandle buds will be.
Foxxy my rose
Watch the high tide. Check yer ropes.
What have we learned?
i have a feeling that claudette (td4) is going to be a bit stronger than the NHC estimates. looking real good on radar right now and even the microwave imagery shows a possible eyewall forming , ala humberto.
It would appear your observation may have some validity. It will be interesting to see if this effects the models later.
I don't see any southward push right now. bill is moving more towards the wnw.
He also said that they still think Ana is a minimal tropical storm. Hurricane hunters will fly into TD 4 as well as Ana later today.
What you don't wanna do, is say she's a TD on the verge of death, then she blows up again prior to hitting the islands and catching people unaware.
Viewing: 4501 - 4551
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 — Blog Index