Hurricane Danielle Update 2

000
WTNT41 KNHC 232033
TCDAT1
HURRICANE DANIELLE DISCUSSION NUMBER   9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL062010
500 PM AST MON AUG 23 2010

THE CONVECTIVE CANOPY OF DANIELLE HAS BECOME MORE AXISYMMETRIC OVER
THE PAST FEW HOURS...INDICATING THAT VERTICAL SHEAR OVER THE SYSTEM
IS NOW RELAXING.  A 1620 UTC AMSR-E MICROWAVE PASS SHOWED A DISTINCT
LOW-LEVEL CENTER OF CIRCULATION THAT IS DISPLACED A LITTLE TO THE
SOUTHEAST OF THE MID-LEVEL CENTER OF ROTATION.  DESPITE THAT
STRUCTURE...DVORAK T-NUMBERS HAVE RISEN TO T4.0 FROM TAFB AND
SAB...AND DANIELLE IS UPGRADED TO A HURRICANE ON THAT BASIS.  THE
CYCLONE APPEARS TO BE GOING THROUGH A PERIOD OF RAPID
INTENSIFICATION...AND THE SHIPS RI GUIDANCE SUGGESTS THAT IT COULD
CONTINUE FOR ANOTHER 12 TO 24 HOURS.  THEREFORE...THE OFFICIAL
FORECAST INDICATES A 25-KT INCREASE OVER THE NEXT 24 HOURS BUT THEN
LEVELS OFF THE INTENSITY TO THE THRESHOLD OF MAJOR HURRICANE BY 48
HOURS.  THIS FORECAST IS VERY CLOSE TO THE SHIPS...LGEM...AND FSU
SUPERENSEMBLE AND SHOWS FASTER STRENGTHENING THAN THE GFDL AND
HWRF.

DANIELLE CONTINUES TO ACCELERATE AND NOW HAS AN INITIAL MOTION OF
290/15.  A BREAK IN THE SUBTROPICAL RIDGE IS LOCATED NORTH OF THE
HURRICANE...AND THIS FEATURE WILL ALLOW THE CYCLONE TO TURN TOWARD
THE NORTHWEST WITHIN THE NEXT 36 HOURS.  MODEL GUIDANCE REMAINS
TIGHTLY-CLUSTERED...AND AGAIN...LITTLE CHANGE WAS REQUIRED FROM THE
PREVIOUS FORECAST.  THE OFFICIAL FORECAST IS VERY CLOSE TO THE MODEL
CONSENSUS TVCN AND CURRENTLY LIES A LITTLE TO THE WEST OF THE
GFDL...HWRF...AND ECMWF AT THE END OF THE FORECAST PERIOD.


FORECAST POSITIONS AND MAX WINDS

INITIAL      23/2100Z 15.4N  41.5W    65 KT
 12HR VT     24/0600Z 16.3N  43.6W    80 KT
 24HR VT     24/1800Z 17.8N  46.2W    90 KT
 36HR VT     25/0600Z 19.6N  48.8W    95 KT
 48HR VT     25/1800Z 21.6N  51.3W   100 KT
 72HR VT     26/1800Z 25.0N  55.0W   100 KT
 96HR VT     27/1800Z 27.5N  57.0W    95 KT
120HR VT     28/1800Z 30.5N  58.5W    95 KT

$$
FORECASTER BERG

Hurricane Danielle Update 1

Due to the fact that Hurricane Danielle MAY pose a long term threat for the general region. I am starting a daily blog post monitoring the progress on this developing weather system until further notice.

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ZCZC MIATCDAT1 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM DANIELLE DISCUSSION NUMBER 5
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062010
500 PM AST SUN AUG 22 2010

STRONG SHOWERS AND THUNDERSTORMS...WITH VERY COLD CLOUD TOPS TO NEAR
-85C...HAVE RECENTLY FORMED IN ASSOCIATION WITH THE CYCLONE...AND
THE LOW-LEVEL CENTER IS NOW EMBEDDED BENEATH THE CONVECTIVE CANOPY.
DVORAK FINAL T-NUMBERS FROM TAFB AND SAB ARE NOW BOTH 2.5...35
KT...AND THE MOST RECENT 3-HOUR AVERAGE ADT FROM UW-CIMSS IS 2.7.
THE DEPRESSION IS THEREFORE UPGRADED TO A 35-KT TROPICAL STORM.

GIVEN THE NORTHWARD MOVEMENT OF THE CENTER OF DANIELLE THROUGH MUCH
OF THE DAY...THE ESTIMATED INITIAL MOTION IS 310/10. HOWEVER...
RECENT SATELLITE IMAGES SUGGEST THAT THE CENTER IS TURNING BACK
TOWARD THE WEST-NORTHWEST...AND THIS MOTION IS EXPECTED TO CONTINUE
FOR THE NEXT 72 HOURS AS THE SYSTEM IS STEERED BY THE SUBTROPICAL
RIDGE TO ITS NORTH. A BREAK IN THE RIDGE BY DAY 3 COULD ALLOW THE
CYCLONE TO TURN TOWARD THE NORTHWEST...BUT DANIELLE IS EXPECTED TO
SLOW DOWN AS IT APPROACHES A NEW RIDGE TO ITS NORTH ON DAY 5. THE
NEW OFFICIAL FORECAST IS A LITTLE NORTH OF THE PREVIOUS FORECAST
DURING THE FIRST 72 HOURS TO ACCOUNT FOR THE INITIAL POSITION...BUT
IT CONVERGES BACK WITH THE PREVIOUS FORECAST ON DAYS 4 AND 5. THERE
HAS BEEN NO SIGNIFICANT SHIFT IN THE MODEL GUIDANCE SINCE THE LAST
ADVISORY...AND THE MULTI-MODEL CONSENSUS TVCN IS EXTREMELY CLOSE TO
OFCI.

WITH THE EXCEPTION OF THE GFDL...THE INTENSITY GUIDANCE HAS
CONTINUED TO SCALE BACK ON THE INTENSIFICATION OF THE CYCLONE.
SLOW STRENGTHENING IS ANTICIPATED FOR MUCH OF THE FORECAST PERIOD
SINCE VERTICAL SHEAR IS CURRENTLY NOT IDEAL...AND SOME DRY AIR
APPEARS TO SURROUND THE SYSTEM. THE STATISTICAL GUIDANCE SEEMS TO
SUGGEST THAT THE VERTICAL SHEAR COULD INCREASE AGAIN AFTER DAY
3...AND THE LGEM DOES NOT EVEN STRENGTHEN THE CYCLONE TO A HURRICANE
DURING THE FORECAST PERIOD. FOR NOW...THE OFFICIAL INTENSITY
FORECAST IS LEFT UNCHANGED OUT OF RESPECT FOR CONTINUITY.

FORECAST POSITIONS AND MAX WINDS

INITIAL 22/2100Z 13.4N 35.1W 35 KT
12HR VT 23/0600Z 14.0N 36.6W 35 KT
24HR VT 23/1800Z 14.9N 39.2W 40 KT
36HR VT 24/0600Z 16.0N 42.0W 50 KT
48HR VT 24/1800Z 17.3N 44.9W 60 KT
72HR VT 25/1800Z 20.0N 50.0W 70 KT
96HR VT 26/1800Z 23.0N 54.0W 75 KT
120HR VT 27/1800Z 25.5N 57.0W 85 KT

$$
FORECASTER BERG

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