Tropical Storm ANA

maquiladora

TROPICAL DEPRESSION TWO SPECIAL DISCUSSION NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022009
600 AM AST TUE AUG 11 2009

FIRST LIGHT VISIBLE SATELLITE IMAGES SHOW THAT THE BROAD LOW
PRESSURE AREA ASSOCIATED WITH A TROPICAL WAVE THAT WE HAVE BEEN
TRACKING OVER THE FAR EASTERN TROPICAL ATLANTIC HAS ACQUIRED
SUFFICENT ORGANIZED DEEP CONVECTION TO BE DESIGNATED AS A TROPICAL
DEPRESSION. THE TROPICAL CYCLONE IS SITUATED OVER MARGINALLY WARM
SEA SURFACE TEMPERATURES AND THE VERTICAL SHEAR IS CURRENTLY RATHER
WEAK. THE OFFICIAL FORECAST SHOWS GRADUAL STRENGHENING OVER THE
NEXT COUPLE OF DAYS AND IS A BLEND OF THE VARIOUS NUMERICAL
GUIDANCE TOOLS. AS USUAL THERE IS CONSIDERABLE UNCERTAINTY AS TO
THE STRENGTH OF THIS SYSTEM LATER IN THE FORECAST PERIOD. IF THE
CYCLONE MOVES FARTHER NORTH THAN ANTICIPATED BELOW IT WILL PROBABLY
ENCOUNTER STRONGER SHEAR AND NOT INTENSIFY AS MUCH AS FORECAST. ON
THE OTHER HAND IF THE SYSTEM MOVES FARTHER SOUTH THAN EXPECTED LATE
IN THE PERIOD...IT WILL PROBABLY BECOME STRONGER THAN ANTICIPATED
HERE.

INITIAL MOTION IS ABOUT 270/11. THIS TRACK IS LIKELY TO MORE OR
LESS CONTINUE FOR THE NEXT 2-3 DAYS DUE TO THE FLOW SOUTH OF A
FAIRLY WELL-ESTABLISHED MID-LEVEL SUBTROPICAL RIDGE. LATER IN THE
PERIOD...A SLIGHT WEAKNESS IN THE RIDGE IS LIKELY TO INDUCE A MORE
WEST-NORTHWESTWARD MOTION. THE OFFICIAL FORECAST IS A LITTLE
SLOWER THAN THE MODEL CONSENSUS AND WELL TO THE SOUTH AND WEST OF
THE BAM TRACKS. THIS IS ALSO SOUTH OF THE LATEST HWRF TRACK.

FORECAST POSITIONS AND MAX WINDS

INITIAL 11/1000Z 14.4N 28.6W 25 KT
12HR VT 11/1800Z 14.6N 30.1W 30 KT
24HR VT 12/0600Z 14.8N 32.3W 35 KT
36HR VT 12/1800Z 15.0N 34.6W 35 KT
48HR VT 13/0600Z 15.2N 36.8W 40 KT
72HR VT 14/0600Z 16.0N 41.2W 45 KT
96HR VT 15/0600Z 17.5N 45.5W 50 KT
120HR VT 16/0600Z 19.5N 49.5W 50 KT

$$
FORECASTER PASCH

billy the squid

Fish spinner me thinks, there are two more areas which need watching though.

has to have been the quietest season for a long time.

maquiladora

This one may be a fish but it's too early to tell yet, but right now I think the main concern is that big wave behind TD2, looks like that will be our first hurricane of the season.

maquiladora

Models for TD2 :



Will probably be Tropical Storm Ana later today.

maquiladora

TD2 is looking a lot less like a fish today (see models above), however it is struggling to reach TS status....




000
WTNT42 KNHC 130840
TCDAT2
TROPICAL DEPRESSION TWO DISCUSSION NUMBER 9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022009
500 AM AST THU AUG 13 2009

THE DEPRESSION HAS A RATHER MEAGER AMOUNT OF CONVECTION THIS MORNING
WITH JUST A FEW CELLS AROUND THE EXPOSED CENTER. SATELLITE
INTENSITY ESTIMATES ARE DROPPING...SO THE INITIAL INTENSITY IS
LOWERED TO 25 KT. IF SIGNIFICANT DEEP CONVECTION DOES NOT DEVELOP
SOON... THE SYSTEM COULD BE DECLARED A REMNANT LOW LATER TODAY.
ASSUMING THE DEPRESSION SURVIVES...THE ENVIRONMENT OVER THE NEXT
FEW DAYS IS MARGINALLY CONDUCIVE FOR SOME STRENGTHENING WITH
GRADUALLY INCREASING WATER TEMPERATURES WEST OF 40W AND PERHAPS A
DECREASE IN MODERATE SOUTHEASTERLY SHEAR. THE INTENSITY FORECAST
IS LOWERED FROM THE PREVIOUS ONE BUT STILL SHOWS THE DEPRESSION
EVENTUALLY BECOMING A TROPICAL STORM. THIS IS A PRETTY LOW
CONFIDENCE INTENSITY FORECAST AS THE DEPRESSION MAY NOT EVEN
SURVIVE THE DAY.

THE SYSTEM HAS BEEN MOVING SLOWER DURING THE PAST FEW HOURS...AND A
TWELVE-HOUR MOTION IS ESTIMATED AT 270/10. MOST OF THE GUIDANCE
SUGGEST THAT THIS WESTWARD MOTION SHOULD CONTINUE FOR A DAY OR SO
WITH A GRADUAL TURN TO THE WEST-NORTHWEST THEREAFTER AS A WEAKNESS
DEVELOPS IN THE SUBTROPICAL RIDGE. THE GLOBAL MODELS NOW INDICATE
THAT THE DEPRESSION COULD BE TOO FAR SOUTH TO BE AFFECTED
SIGNIFICANTLY BY THE WEAKNESS IN THE RIDGE AND HAVE SHIFTED THE
TRACK EQUATORWARD AS A RESULT. THE HWRF CONTINUES ON ITS OWN BY
MOVING THE SYSTEM MORE TO THE NORTH...WHILE THE REST OF THE
GUIDANCE IS PRETTY WELL-CLUSTERED ON A MORE SOUTHERN PATH. THE
OFFICIAL FORECAST IS ADJUSTED SOUTHWARD AND WITH MANY RELIABLE
MODELS STILL SOUTH OF THE NHC TRACK...IT WOULD NOT BE SURPRISING TO
SEE THE FORECAST MOVE FARTHER SOUTH LATER ON.


FORECAST POSITIONS AND MAX WINDS

INITIAL 13/0900Z 14.0N 36.9W 25 KT
12HR VT 13/1800Z 14.0N 38.5W 25 KT
24HR VT 14/0600Z 14.2N 40.7W 30 KT
36HR VT 14/1800Z 14.4N 43.0W 35 KT
48HR VT 15/0600Z 14.9N 45.9W 40 KT
72HR VT 16/0600Z 16.5N 52.0W 40 KT
96HR VT 17/0600Z 19.0N 59.0W 40 KT
120HR VT 18/0600Z 22.5N 65.0W 35 KT

$$
FORECASTER BLAKE

maquiladora

TD2 is now Tropical Storm Ana....

000
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.

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