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
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Do you know if a good site that has information on terms such as tighten up?...im kinda curious exactly what you mean when you say that...
Means it could be revving up...intensifying.....
Good morning Stephanie...my neighbor..:) I just hope we don't get one this year at all.. we had enough last year...
TROPICAL DEPRESSION FOUR ADVISORY NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL042009
500 AM EDT SUN AUG 16 2009
...TROPICAL STORM WARNING ISSUED FOR NEW DEPRESSION IN THE EASTERN
GULF OF MEXICO...
AT 5 AM EDT...0900 UTC...A TROPICAL STORM WARNING HAS BEEN ISSUED
FROM THE ALABAMA/FLORIDA BORDER EASTWARD TO THE SUWANNEE RIVER
FLORIDA. A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM
CONDITIONS ARE EXPECTED SOMEWHERE WITHIN THE WARNING AREA WITHIN 24
HOURS.
FOR STORM INFORMATION SPECIFIC TO YOUR AREA PLEASE MONITOR PRODUCTS
ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE FORECAST OFFICE.
AT 500 AM EDT...0900 UTC...THE CENTER OF TROPICAL DEPRESSION FOUR
WAS LOCATED NEAR LATITUDE 27.7 NORTH...LONGITUDE 83.9 WEST OR ABOUT
90 MILES...140 KM...WEST-SOUTHWEST OF TAMPA FLORIDA AND ABOUT 155
MILES...245 KM...SOUTH-SOUTHEAST OF APALACHICOLA FLORIDA.
THE DEPRESSION IS MOVING TOWARD THE NORTH-NORTHWEST NEAR 16
MPH...AND THIS MOTION IS EXPECTED TO CONTINUE TODAY. ON THE
FORECAST TRACK...THE CENTER OF THE DEPRESSION SHOULD BE VERY NEAR
THE NORTHERN GULF COAST OF FLORIDA BY LATE THIS AFTERNOON.
MAXIMUM SUSTAINED WINDS ARE NEAR 35 MPH...55 KM/HR...WITH HIGHER
GUSTS. STRENGTHENING IS EXPECTED AND THE DEPRESSION IS FORECAST TO
BECOME A TROPICAL STORM PRIOR TO REACHING THE COASTLINE.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1011 MB...29.85 INCHES.
RAINFALL ACCUMULATIONS OF 3 TO 5 INCHES...WITH ISOLATED MAXIMUM
AMOUNTS OF 10 INCHES ACROSS PORTIONS OF NORTH FLORIDA NEAR THE PATH
OF THE CENTER.
COASTAL STORM SURGE FLOODING OF 3 TO 5 FEET ABOVE NORMAL TIDE
LEVELS CAN BE EXPECTED NEAR AND TO THE EAST OF WHERE THE CENTER
MAKES LANDFALL.
...SUMMARY OF 500 AM EDT INFORMATION...
LOCATION...27.7N 83.9W
MAXIMUM SUSTAINED WINDS...35 MPH
PRESENT MOVEMENT...NORTH-NORTHWEST OR 330 DEGREES AT 16 MPH
MINIMUM CENTRAL PRESSURE...1011 MB
AN INTERMEDIATE ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE
CENTER AT 800 AM EDT FOLLOWED BY THE NEXT COMPLETE ADVISORY AT 1100
AM EDT.
$$
FORECASTER FRANKLIN
Ana is pulling against dry:
Now:
Yesterday:
WTNT34 KNHC 160858
TCPAT4
BULLETIN
TROPICAL DEPRESSION FOUR ADVISORY NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL042009
500 AM EDT SUN AUG 16 2009
...TROPICAL STORM WARNING ISSUED FOR NEW DEPRESSION IN THE EASTERN
GULF OF MEXICO...
AT 5 AM EDT...0900 UTC...A TROPICAL STORM WARNING HAS BEEN ISSUED
FROM THE ALABAMA/FLORIDA BORDER EASTWARD TO THE SUWANNEE RIVER
FLORIDA. A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM
CONDITIONS ARE EXPECTED SOMEWHERE WITHIN THE WARNING AREA WITHIN 24
HOURS.
FOR STORM INFORMATION SPECIFIC TO YOUR AREA PLEASE MONITOR PRODUCTS
ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE FORECAST OFFICE.
AT 500 AM EDT...0900 UTC...THE CENTER OF TROPICAL DEPRESSION FOUR
WAS LOCATED NEAR LATITUDE 27.7 NORTH...LONGITUDE 83.9 WEST OR ABOUT
90 MILES...140 KM...WEST-SOUTHWEST OF TAMPA FLORIDA AND ABOUT 155
MILES...245 KM...SOUTH-SOUTHEAST OF APALACHICOLA FLORIDA.
THE DEPRESSION IS MOVING TOWARD THE NORTH-NORTHWEST NEAR 16
MPH...AND THIS MOTION IS EXPECTED TO CONTINUE TODAY. ON THE
FORECAST TRACK...THE CENTER OF THE DEPRESSION SHOULD BE VERY NEAR
THE NORTHERN GULF COAST OF FLORIDA BY LATE THIS AFTERNOON.
MAXIMUM SUSTAINED WINDS ARE NEAR 35 MPH...55 KM/HR...WITH HIGHER
GUSTS. STRENGTHENING IS EXPECTED AND THE DEPRESSION IS FORECAST TO
BECOME A TROPICAL STORM PRIOR TO REACHING THE COASTLINE.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1011 MB...29.85 INCHES.
RAINFALL ACCUMULATIONS OF 3 TO 5 INCHES...WITH ISOLATED MAXIMUM
AMOUNTS OF 10 INCHES ACROSS PORTIONS OF NORTH FLORIDA NEAR THE PATH
OF THE CENTER.
COASTAL STORM SURGE FLOODING OF 3 TO 5 FEET ABOVE NORMAL TIDE
LEVELS CAN BE EXPECTED NEAR AND TO THE EAST OF WHERE THE CENTER
MAKES LANDFALL.
...SUMMARY OF 500 AM EDT INFORMATION...
LOCATION...27.7N 83.9W
MAXIMUM SUSTAINED WINDS...35 MPH
PRESENT MOVEMENT...NORTH-NORTHWEST OR 330 DEGREES AT 16 MPH
MINIMUM CENTRAL PRESSURE...1011 MB
AN INTERMEDIATE ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE
CENTER AT 800 AM EDT FOLLOWED BY THE NEXT COMPLETE ADVISORY AT 1100
AM EDT.
$$
FORECASTER FRANKLIN
TCPAT4
BULLETIN
TROPICAL DEPRESSION FOUR ADVISORY NUMBER 1
MPH...AND THIS MOTION IS EXPECTED TO CONTINUE TODAY. ON THE
FORECAST TRACK...THE CENTER OF THE DEPRESSION SHOULD BE VERY NEAR
THE NORTHERN GULF COAST OF FLORIDA BY LATE THIS AFTERNOON.
WTNT24 KNHC 160858
TCMAT4
TROPICAL DEPRESSION FOUR FORECAST/ADVISORY NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL042009
0900 UTC SUN AUG 16 2009
AT 5 AM EDT...0900 UTC...A TROPICAL STORM WARNING HAS BEEN ISSUED
FROM THE ALABAMA/FLORIDA BORDER EASTWARD TO THE SUWANNEE RIVER
FLORIDA. A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM
CONDITIONS ARE EXPECTED SOMEWHERE WITHIN THE WARNING AREA WITHIN 24
HOURS.
TROPICAL DEPRESSION CENTER LOCATED NEAR 27.7N 83.9W AT 16/0900Z
POSITION ACCURATE WITHIN 20 NM
PRESENT MOVEMENT TOWARD THE NORTH-NORTHWEST OR 330 DEGREES AT 14 KT
ESTIMATED MINIMUM CENTRAL PRESSURE 1011 MB
MAX SUSTAINED WINDS 30 KT WITH GUSTS TO 40 KT.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.
REPEAT...CENTER LOCATED NEAR 27.7N 83.9W AT 16/0900Z
AT 16/0600Z CENTER WAS LOCATED NEAR 27.0N 83.5W
FORECAST VALID 16/1800Z 29.2N 85.0W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 45NE 45SE 0SW 30NW.
FORECAST VALID 17/0600Z 31.0N 86.7W...INLAND
MAX WIND 40 KT...GUSTS 50 KT.
34 KT... 0NE 60SE 0SW 0NW.
FORECAST VALID 17/1800Z 33.0N 87.5W...DISSIPATING INLAND
MAX WIND 20 KT...GUSTS 30 KT.
FORECAST VALID 18/0600Z...DISSIPATED
REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 27.7N 83.9W
NEXT ADVISORY AT 16/1500Z
$$
FORECASTER FRANKLIN
I gotta agree there. And the year before and 2006 was a very good year :), and the year before that...Lol. I'm tired.
Yup people are in for a rude awakening
Wouldn't surprise me to find a special advisory at some point within the next couple of hours saying we have Claudette.
The real threat is Bill.
MAX WIND 40 KT...GUSTS 50 KT.
34 KT... 0NE 60SE 0SW 0NW.
Here in Defuniak Springs,FL....I'm at 30.7N and 86.1W....
Those coordinates are within 35 miles of me...and I'm on the WNW side of DFS.
Center may cross right over here.
Haha, I should be going to sleep right about now...
We don't need rain or 40-50 mph winds. I've had close to 1 1/2 feet of rain since July 1st. Trees all over the place here. Usually a 40-50 mph wind puts branches down.
Tropical Cyclone Advisory #17
SEVERE TROPICAL CYCLONE GUILLERMO (EP102009)
9:00 AM UTC August 16 2009
====================================
At 6:00 AM UTC, Hurricane Guillermo (973 hPa) located at 19.8N 137.4W or 1000 NM east of Hilo, Hawaii has sustained winds of 85 knots with gusts of 105 knots. The cyclone is reported as moving west at 13 knots.
Hurricane-force Winds
=====================
35 NM from the center
Gale/Storm-force Winds
================
105 NM from the center
Forecast and Intensity
======================
12 HRS: 20.3N 139.4W - 75 knots (SSHS-1 Cyclone)
24 HRS: 21.2N 142.1W - 60 knots (Tropical Storm)
48 HRS: 23.3N 147.5W - 40 knots (Tropical Storm)
72 HRS: 26.0N 153.0W - 30 knots (Tropical Depression)
LOL...that's why I'm Wal-Mart bound....place will be dead at 6 am.
Thanks
JoJo
Tropical Cyclone Advisory #1
TROPICAL DEPRESSION (MAKA)
15:00 PM JST August 16 2009
=========================================
SUBJECT: Tropical Depression Near Wake Island
At 6:00 AM UTC, Tropical Depression, Former Maka (1008 hPa) located at 16.1N 174.0E has 10 minute sustained winds of 30 knots with gusts of 50 knots. The depression is reported as moving norteast at 11 knots
Forecast and Intensity
======================
24 HRS: 17.8N 175.0E - 35 knots (CAT 1/Tropical Storm)
Tropical Cyclone Formation Alert (0600z 16AUG)
=============================================
An area of convection (94W) located at 11.2N 161.4E or 315 NM northeast of Pohnpei. Recent animted multispectral satellite imagery indicates that convection is starting to consolidate around a developed low level circulation center. The European Solution of the 2330z ASCAT Pass shows a much improved low level circulation center with strongest winds (20 knots) in the northwest and southeast quadrants. Additionally, a 2321z Composite METOPA Microwave image depicts convective bands starting to wrap into the low level circulation center from the northeast and southwest. Finally, animated water vapor imagery indicates that the system is in an area of low vertical wind shear with some poleward outflow into a tropical upper tropospheric trough located to the northeast.
Maximum sustained winds near the center is 15-20 knots with a minimum sea level pressure of 1007 MB. Due to the increased consolidation of the low level circulation center, the potential for this disturbance to form into a significant tropical cyclone within the next 24 hours is UPGRADED TO GOOD.
WTNT84 KNHC 160905
TCVAT4
FOUR WATCH/WARNING BREAKPOINTS/ADVISORY NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL042009
500 AM EDT SUN AUG 16 2009
.TROPICAL DEPRESSION FOUR
FLZ001-002-003-004-005-006-008-012-014-015-018-027-028-034-
161500-
/O.NEW.KNHC.TR.W.1004.090816T0900Z-000000T0000Z/
500 AM EDT SUN AUG 16 2009
AL/FL-BORDER 30.30N 87.45W
SUWANNEE-RIVER-FL 29.30N 83.15W
$$
ATTN...WFO...MOB...TAE...
Yup... We discussed it on pg 75... specifically post, around post 3713..
And you're in PC...correct? You'll be close to the COC....
WTNT84 KNHC 160905
TCVAT4
FOUR WATCH/WARNING BREAKPOINTS/ADVISORY NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL042009
500 AM EDT SUN AUG 16 2009
.TROPICAL DEPRESSION FOUR
FLZ001-002-003-004-005-006-008-012-014-015-018-027-028-034-
161500-
/O.NEW.KNHC.TR.W.1004.090816T0900Z-000000T0000Z/
500 AM EDT SUN AUG 16 2009
AL/FL-BORDER 30.30N 87.45W
SUWANNEE-RIVER-FL 29.30N 83.15W
$$
ATTN...WFO...MOB...TAE...
True, the rain can be bad in any tropical systems, but as far as the wind goes this is not much different than an afternoon thunderstorm.
Takes it right over here, through Paxton and Laurel Hill,Fl....Florala,AL..up through sweet home Alabama....
I think it has even more of a chance to be picked up by it.
Slow Bill/Fast trough = + chance of recurve.
Fast Bill/slow trough = - chance of recurve.
I think anyway.
WTNT44 KNHC 160858
TCDAT4
TROPICAL DEPRESSION FOUR DISCUSSION NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL042009
500 AM EDT SUN AUG 16 2009
DATA FROM THE WFO TAMPA RADAR INDICATE THAT THE DISTURBANCE IN THE
EASTERN GULF OF MEXICO HAS BECOME SIGNIFICANTLY BETTER ORGANIZED
OVERNIGHT. A QUIKSCAT PASS NEAR 00Z SUGGESTED THAT THERE PROBABLY
WAS A CLOSED SURFACE CIRCULATION. GIVEN THIS...ADVISORIES ARE BEING
INITIATED ON A NEW TROPICAL DEPRESSION. ALTHOUGH THERE WAS A SHIP
REPORT FROM A CARNIVAL CRUISE LINE VESSEL OF 40 KT...THIS REPORT IS
NOT CONSIDERED TO BE REPRESENTATIVE OF THE SURFACE WINDS. DOPPLER
VELOCITIES FROM THE TAMPA RADAR ALSO DO NOT SUPPORT TROPICAL STORM
STRENGTH AT THIS TIME. HOWEVER...THE EXCELLENT RADAR PRESENTATION
AND DEEP CONVECTION SUGGESTS THAT STORM STATUS IS LIKELY TO BE
ATTAINED SOON. VERTICAL SHEAR IS VERY LOW...AND THE INTENSITY
GUIDANCE FROM THE HWRF AND GFDL SUGGEST A MIDDLE-RANGE TROPICAL
STORM BY LANDFALL. IT SHOULD BE NOTED THAT SOME ADDITIONAL
STRENGTHENING PRIOR TO LANDFALL BUT AFTER THE 12 HOUR 45 KT
FORECAST INTENSITY SHOWN BELOW IS LIKELY.
THE INITIAL MOTION IS 330/13. THE CYCLONE IS MOVING AROUND THE
PERIPHERY OF THE SUBTROPICAL RIDGE AND IS EXPECTED TO MAINTAIN THIS
APPROXIMATE TRACK UNTIL LANDFALL. THE OFFICIAL FORECAST IS CLOSE TO
A CONSENSUS OF A FAIRLY TIGHTLY CLUSTERED GUIDANCE SUITE.
THIS IS A VERY SMALL TROPICAL CYCLONE...AND ITS EFFECTS ARE LIKELY
TO REMAIN RATHER CLOSE TO THE PATH OF THE CENTER.
FORECAST POSITIONS AND MAX WINDS
INITIAL 16/0900Z 27.7N 83.9W 30 KT
12HR VT 16/1800Z 29.2N 85.0W 45 KT
24HR VT 17/0600Z 31.0N 86.7W 40 KT...INLAND
36HR VT 17/1800Z 33.0N 87.5W 20 KT...DISSIPATING INLAND
48HR VT 18/0600Z...DISSIPATED
$$
FORECASTER FRANKLIN
but if it moves too slow wouldn't the trough miss it? I remember there was a mode yesterday slowing bill down a bit "GFS" and the trough picks it up but then bill turns west after that, I know its changed but just a curiousity
Viewing: 4151 - 4201
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