000
WTNT41 KNHC 040242
TCDAT1

TROPICAL DEPRESSION SIX DISCUSSION NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL062012
1100 PM AST FRI AUG 03 2012

THE TROPICAL WAVE WHICH EMERGED FROM WEST AFRICA YESTERDAY QUICKLY
DEVELOPED A WELL-DEFINED CENTER ALONG WITH SUBSTANTIAL DEEP
CONVECTION TODAY. THE COLD CLOUD TOPS ARE MAINLY SOUTH OF THE
CENTER DUE TO THE IMPINGING EFFECTS OF MODERATE NORTHEASTERLY
VERTICAL SHEAR. DVORAK CURRENT INTENSITY NUMBERS AT 00Z WERE 2.0
FROM TAFB AND 1.5 FROM SAB...AND THE CONVECTIVE STRUCTURE HAS
PERSISTED AND IMPROVED SLIGHTLY SINCE THAT TIME. THUS ADVISORIES
ARE BEING INITIATED ON TROPICAL DEPRESSION SIX. IT APPEARS THAT THE
GENESIS OF THIS CYCLONE WAS AIDED BY THE INTERACTION OF THE
WESTWARD MOVING TROPICAL WAVE WITH AN EASTWARD MOVING
CONVECTIVELY-COUPLED KELVIN WAVE AS DEPICTED BY ANALYSES FROM
SUNY-ALBANY.

MOVEMENT OF THE CYCLONE IS CURRENTLY 290 DEGREES AT 14 KT...AS THE
SYSTEM IS PRIMARILY BEING STEERED BY A MID TO UPPER LEVEL RIDGE
NORTH OF THE CYCLONE. FINDING THE INITIAL POSITION WAS
SUBSTANTIALLY AIDED BY SOME SSMI AND WINDSAT MICROWAVE IMAGERY FROM
NRL. THE TROPICAL CYCLONE SHOULD CONTINUE MOVING WEST- NORTHWEST
FOR THE NEXT DAY OR TWO IN THE DEEP LAYER FLOW. AFTER ABOUT TWO
DAYS...IT IS ANTICIPATED THAT THE CYCLONE WILL BE WEAKENING AND
THUS ADVECTED ALONG WESTWARD BY THE LOWER TROPOSPHERIC WINDS. THE
FORECAST TRACK FOLLOWS CLOSELY THE TCVA CONSENSUS OF THE DYNAMICAL
MODELS.

WHILE THE CYCLONE UNDERWENT GENESIS RATHER QUICKLY TODAY...IT MAY BE
THAT THE SYSTEM WILL NOT DEVELOP MUCH FURTHER.  CURRENTLY THE
CYCLONE IS BEING AFFECTED BY MODERATE NORTHEASTERLY VERTICAL SHEAR.
WHILE THIS SHOULD DIMINISH IN ABOUT A DAY...THE COMBINATION OF ONLY
LUKEWARM SEA SURFACE TEMPERATURES AND A FAIRLY DRY STABLE
ATMOSPHERE MAY ALLOW THE CYCLONE TO PEAK ONLY AS A LOW-END TROPICAL
STORM.  AFTER ABOUT TWO DAYS...THE SYSTEM SHOULD BE WEAKENING AND
IT MAY NO LONGER BE A TROPICAL CYCLONE BY DAY FOUR OR FIVE AS
SUGGESTED BY THE GLOBAL AND REGIONAL HURRICANE MODELS.  THE
INTENSITY FORECAST IS A BLEND OF THE STATISTICAL LGEM AND SHIPS
MODELS AND THE DYNAMICAL GFDL AND HWRF MODELS...WITH A BIT MORE
EMPHASIS ON THE LATTER.


FORECAST POSITIONS AND MAX WINDS

INIT  04/0300Z 13.8N  27.8W   30 KT  35 MPH
 12H  04/1200Z 14.5N  29.5W   35 KT  40 MPH
 24H  05/0000Z 15.1N  31.8W   40 KT  45 MPH
 36H  05/1200Z 15.4N  34.0W   40 KT  45 MPH
 48H  06/0000Z 15.6N  36.0W   35 KT  40 MPH
 72H  07/0000Z 16.2N  41.1W   30 KT  35 MPH
 96H  08/0000Z 16.5N  47.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  09/0000Z 16.5N  53.0W   20 KT  25 MPH...POST-TROP/REMNT LOW

$$
FORECASTER LANDSEA

000
WTNT61 KNHC 041132
TCUAT1

TROPICAL STORM FLORENCE TROPICAL CYCLONE UPDATE
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL062012
800 AM AST SAT AUG 04 2012

...TROPICAL DEPRESSION SIX BECOMES A TROPICAL STORM...

SATELLITE IMAGES INDICATE THAT TROPICAL DEPRESSION SIX HAS BECOME
TROPICAL STORM FLORENCE WITH MAXIMUM SUSTAINED WINDS OF 40 MPH...65
KM/HR. 


SUMMARY OF 0800 AM AST...1200 UTC...INFORMATION
--------------------------------------------------
LOCATION...14.6N 29.7W
ABOUT 330 MI...530 KM W OF THE SOUTHERNMOST CAPE VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...WNW OR 295 DEGREES AT 16 MPH...26 KM/H
MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES

$$
FORECASTER BLAKE

000
WTNT41 KNHC 042032
TCDAT1

TROPICAL STORM FLORENCE DISCUSSION NUMBER   4
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL062012
500 PM AST SAT AUG 04 2012

AFTER LOOKING A LITTLE RAGGED EARLIER...CONVECTION HAS REDEVELOPED
NEAR THE CENTER OF FLORENCE...WHICH APPEARS TO BE THE START OF A
CENTRAL DENSE OVERCASE PATTERN.  SUBJECTIVE SATELLITE INTENSITY
ESTIMATES WERE 35 KT AND 45 KT FROM SAB AND TAFB RESPECTIVELY.
SINCE A TRMM MICROWAVE PASS FROM EARLIER TODAY SUGGESTED THAT SOME
PRIMITIVE INNER CORE FEATURES HAD FORMED...AND BOTH AMSU AND ADT
DATA INDICATE A STRONGER CYCLONE...THE INITIAL INTENSITY WILL BE
BUMPED UP TO 45 KT. 

THE CURRENT SYMMETRIC OUTFLOW PATTERN WITH FLORENCE APPEARS
FAVORABLE FOR FURTHER INTENSIFICATION.  HOWEVER...THE SYSTEM IS
PASSING OVER WATERS COOLER THAN 26.5C...AND IS APPROACHING A MORE
STABLE AND DRY ENVIRONMENT AS INDICATED BY EUMETSAT RGB AIRMASS
IMAGERY.  THE INTENSITY GUIDANCE HAS A WIDE RANGE OF POSSIBILITIES.
THE STATISTICAL-BASED TOOLS FORECAST FLORENCE TO BE NEAR OR ABOVE
HURRICANE STRENGTH IN A DAY OR TWO...WHICH IS CONTRASTED WITH THE
WEAKENING FORECAST BY THE HWRF/GFDL MODELS.  THE OFFICIAL FORECAST
IS JUST A BIT ABOVE THE INTENSITY CONSENSUS AND IS HIGHER THAN THE
PREVIOUS ONE.  GIVEN THE EARLIER MICROWAVE STRUCTURE...IT IS
TEMPTING TO RAISE THE WIND PREDICTION MORE THAN WHAT IS INDICATED
BELOW...BUT I HAVE ELECTED TO REMAIN CONSERVATIVE ON THIS FORECAST
CONSIDERING THE MARGINAL ENVIRONMENT. 

THE INITIAL MOTION ESTIMATE IS A LITTLE SLOWER...295/13.  A BUILDING
MID-TROPOSPHERIC HIGH OVER THE EASTERN ATLANTIC OCEAN IS EXPECTED
TO CAUSE FLORENCE TO BEND TO A WESTWARD HEADING DURING THE NEXT DAY
OR TWO.  HOWEVER...THE GLOBAL MODELS HAVE A WIDER SPREAD THAN
EARLIER TODAY...WITH THE ECMWF AND GFS SHOWING LITTLE RUN-TO-RUN
CONSISTENCY.  GENERALLY THE MODELS THAT ARE FORECASTING A MORE
POWERFUL SYSTEM...SUCH AS THE GFS...ARE CAUSING FLORENCE TO TURN
NORTHWESTWARD AROUND DAY 4 IN RESPONSE TO A WEAKNESS IN THE RIDGE.
A WEAKER CYCLONE...AS INDICATED BY THE ECMWF...WOULD PROBABLY JUST
CONTINUE MOVING WESTWARD.  SINCE THE LATEST INTENSITY FORECAST IS
BETWEEN THESE TWO EXTREMES...THE LATEST NHC FORECAST IS CLOSE TO
THE MODEL CONSENSUS...JUST A BIT NORTH OF THE PREVIOUS FORECAST IN
THE LONG RANGE PERIOD.


FORECAST POSITIONS AND MAX WINDS

INIT  04/2100Z 15.3N  31.7W   45 KT  50 MPH
 12H  05/0600Z 15.8N  33.4W   50 KT  60 MPH
 24H  05/1800Z 16.2N  35.7W   50 KT  60 MPH
 36H  06/0600Z 16.6N  38.1W   45 KT  50 MPH
 48H  06/1800Z 17.1N  41.2W   45 KT  50 MPH
 72H  07/1800Z 18.5N  47.8W   40 KT  45 MPH
 96H  08/1800Z 20.5N  54.0W   35 KT  40 MPH
120H  09/1800Z 23.0N  59.0W   30 KT  35 MPH...POST-TROP/REMNT LOW

$$
FORECASTER BLAKE

000
WTNT41 KNHC 050250
TCDAT1

TROPICAL STORM FLORENCE DISCUSSION NUMBER   5
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL062012
1100 PM AST SAT AUG 04 2012

FLORENCE IS BECOMING BETTER ORGANIZED.  BANDING FEATURES ASSOCIATED
WITH THE CYCLONE HAVE RECENTLY DISSIPATED IN FAVOR OF A CENTRAL
DENSE OVERCAST.  EARLIER TRMM AND WINDSAT OVERPASSES REVEAL A WELL-
DEFINED LOW-LEVEL STRUCTURE UNDERNEATH THIS NEW CONVECTIVE MASS...
WITH A NEARLY CLOSED RING OF CONVECTION NOW PRESENT.  A DVORAK
INTENSITY ESTIMATE OF 3.5/55 KT FROM TAFB AT 0000 UTC AND THREE-
HOURLY AVERAGED ADT VALUES OF AROUND 3.3 ARE THE BASIS FOR
INCREASING THE INITIAL INTENSITY TO 50 KT FOR THIS ADVISORY.

THE INTENSITY FORECAST IS TRICKY.  DESPITE BEING IN A LOW-SHEAR
ENVIRONMENT...FLORENCE IS FORECAST TO MOVE THROUGH A TONGUE OF
MARGINALLY WARM WATERS OVER THE NEXT COUPLE OF DAYS.  IN ADDITION...
EUMETSAT RGB SATELLITE IMAGERY INDICATES THAT THE CYCLONE IS
SURROUNDED BY A RATHER DRY AIR MASS...AND THIS AIR MASS SHOULD
ACCOMPANY FLORENCE ON ITS WESTWARD TREK. THESE NEGATIVE FACTORS
SUGGEST THAT ANY STRENGTHENING IN THE SHORT TERM WOULD NOT LIKELY
BE SIGNIFICANT.  BEYOND 72 HOURS...GLOBAL MODELS SHOW FLORENCE
ENCOUNTERING INCREASING SOUTHWESTERLY SHEAR ASSOCIATED WITH AN
UPPER-LEVEL TROUGH OVER THE CENTRAL ATLANTIC.  EVEN THOUGH THE
STORM WILL BE MOVING OVER WARMER WATERS BY THIS TIME...THE SHEAR
SHOULD BE STRONG ENOUGH TO INDUCE WEAKENING.  THE NEW NHC INTENSITY
FORECAST IS ADJUSTED UPWARD THROUGH 48 HOURS BASED ON
CURRENT TRENDS AND IS ABOUT THE SAME AS THE PREVIOUS FORECAST AFTER
THAT TIME.  THE FORECAST IS IN EXCELLENT AGREEMENT WITH THE LATEST
SHIPS/LGEM OUTPUT.

THE INITIAL MOTION ESTIMATE IS 295/13. A MID-LEVEL RIDGE OVER THE
EASTERN ATLANTIC IS EXPECTED TO BUILD WESTWARD DURING THE NEXT
SEVERAL DAYS...WHICH WILL CAUSE THE TRACK OF FLORENCE TO BEND TOWARD
THE WEST.  LATE IN THE FORECAST PERIOD...THE CYCLONE IS EXPECTED TO
ENCOUNTER A WEAKNESS IN THE SUBTROPICAL RIDGE OVER THE CENTRAL
ATLANTIC WHICH SHOULD INDUCE A WEST-NORTHWESTERLY HEADING. ALTHOUGH
THE SPREAD IN THE TRACK GUIDANCE HAS DECREASED THIS CYCLE...IT
REMAINS FAIRLY SIGNIFICANT BEYOND 72 HOURS.  THE DIFFERENCE IN TRACK
SOLUTIONS AT LATER TIMES APPEARS DEPENDENT ON THE VERTICAL DEPTH/
STRENGTH OF THE CYCLONE...WITH THE ECMWF/GFDL/HWRF FORECASTING A
WEAKER VERSION OF FLORENCE AND THE GFS FAVORING A STRONGER SYSTEM.
THE NEW NHC FORECAST TRACK REMAINS IN BETWEEN THESE TWO EXTREMES
BUT HAS BEEN ADJUSTED TOWARD THE CAMP OF MODELS FAVORING A WEAKER
CYCLONE GIVEN THE SHEAR FORECAST.


FORECAST POSITIONS AND MAX WINDS

INIT  05/0300Z 16.1N  33.0W   50 KT  60 MPH
 12H  05/1200Z 16.5N  34.8W   55 KT  65 MPH
 24H  06/0000Z 17.0N  37.2W   60 KT  70 MPH
 36H  06/1200Z 17.5N  39.7W   60 KT  70 MPH
 48H  07/0000Z 18.1N  42.6W   60 KT  70 MPH
 72H  08/0000Z 19.3N  49.0W   45 KT  50 MPH
 96H  09/0000Z 20.9N  55.1W   35 KT  40 MPH
120H  10/0000Z 23.5N  60.5W   30 KT  35 MPH...POST-TROP/REMNT LOW

$$
FORECASTER KIMBERLAIN