000
WTNT43 KNHC 302047
TCDAT3
TROPICAL STORM FIONA DISCUSSION NUMBER   1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL082010
500 PM EDT MON AUG 30 2010

EARLIER TODAY...ABOUT 30 DROPSONDES WERE RELEASED DURING A G-V
RESEARCH MISSION BEING CONDUCTED BY THE NATIONAL CENTER FOR
ATMOSPHERIC RESEARCH NEAR THE AREA OF LOW PRESSURE LOCATED ABOUT
800 MILES EAST OF THE LESSER ANTILLES.  ONE OF THE DROPSONDES
MEASURED A SURFACE WIND OF 35 KT APPROXIMATELY 120 N MI TO THE
NORTHEAST OF THE ESTIMATED CENTER.  THIS MEASUREMENT AGREES WITH AN
ASCAT PASS FROM 1208 UTC...WHICH SHOWED A SWATH OF 30-35 KT WINDS
IN THAT SAME AREA.  CONVECTION HAS BEEN A LITTLE THIN FOR MOST OF
THE DAY...BUT BANDING FEATURES HAVE RECENTLY BECOME MORE PROMINENT
MAINLY OVER THE WESTERN SEMICIRCLE.  GIVEN THE INCREASE IN
CONVECTION AND SINCE TROPICAL STORM FORCE WINDS ARE ALREADY
OCCURRING...THE SYSTEM IS BEING DIRECTLY UPGRADED TO TROPICAL STORM
FIONA.

SINCE FIONA STILL LACKS SOME ORGANIZATION AND THE WIND FIELD IS
SOMEWHAT LARGE...THE CYCLONE WILL LIKELY HAVE A DIFFICULT TIME
INTENSIFYING OVER THE NEXT DAY OR SO.  I DO NOT BELIEVE THIS
STRUCTURE IS HANDLED WELL BY THE STATISTICAL INTENSITY
GUIDANCE...WHICH INTENSIFY FIONA TO A HURRICANE IN 36 TO 48
HOURS...SO I AM INCLINED TO LEAN CLOSER TO THE DYNAMICAL GFDL AND
HWRF AT THIS POINT.  IN FACT...THE GFS DISSIPATES THE CYCLONE WITHIN
2 TO 3 DAYS.  THE OFFICIAL FORECAST THEREFORE SHOWS MINIMAL
STRENGTHENING OVER THE NEXT 1 TO 2 DAYS AND THEN LEVELS OUT THE
INTENSITY FOR DAYS 3 THROUGH 5...WHEN IT APPEARS THAT INCREASING
VERTICAL SHEAR COULD BECOME A LIMITING FACTOR.

THE SURFACE CENTER HAS BEEN A LITTLE DIFFICULT TO LOCATE...AND THE
INITIAL MOTION IS AN UNCERTAIN 270/21.  TRACK MODEL GUIDANCE IS IN
GOOD AGREEMENT FOR THE NEXT 48 HOURS AND SHOWS FIONA TURNING TOWARD
THE NORTHWEST...GENERALLY FOLLOWING EARL AROUND THE WESTERN
PERIPHERY OF THE SUBTROPICAL RIDGE.  AFTER THAT...THE
GFDL...HWRF...AND GFS KEEP FIONA AS A WEAK SYSTEM AND SHOW IT
CONTINUING TO THE NORTH IN THE LOW-LEVEL FLOW BEHIND EARL.  THE
ECMWF...ON THE OTHER HAND...SHOWS A STRONGER FIONA AND SUGGESTS
THAT THE SUBTROPICAL RIDGE COULD BUILD BACK TO THE WEST BEFORE THE
CYCLONE CAN RECURVE.  THE OFFICIAL FORECAST IS VERY CLOSE TO THE
MODEL CONSENSUS TVCN FOR THE FIRST 48 HOURS BUT THEN LIES A LITTLE
NORTH OF THE CONSENSUS IN FAVOR OF THE TRACKS OF THE WEAKER GFDL
AND HWRF.


FORECAST POSITIONS AND MAX WINDS

INITIAL      30/2100Z 14.4N  48.7W    35 KT
 12HR VT     31/0600Z 14.9N  51.9W    35 KT
 24HR VT     31/1800Z 15.8N  55.9W    40 KT
 36HR VT     01/0600Z 17.2N  59.2W    45 KT
 48HR VT     01/1800Z 19.3N  62.0W    45 KT
 72HR VT     02/1800Z 24.0N  66.0W    40 KT
 96HR VT     03/1800Z 27.5N  68.0W    40 KT
120HR VT     04/1800Z 29.0N  69.0W    40 KT

$$
FORECASTER BERG

Pues si os soy sincero, no me explico cómo denominan a este sistema tormenta tropical................... Tiene un aspecto pobrísimo a pesar de lo que dicen en el boletín de discusión

Sigo sin ver que el outflow de EARL esté afectando a FIONA, en cuanto a niveles de cizalladura. Pienso que esto no es así. Otra cosa es que FIONA se esté encontrando con la huella oceánica fría que va dejando EARL en su lento camino absorbiendo energía. Esto sí es posible, lo que combinado con aire seco, puede interferir irremediablemente en su progreso. De todos modos, habrá que mantener vigilancia sobre él, por si acaso. Se le observa mucha convección a estas horas.

000
WTNT43 KNHC 310252
TCDAT3
TROPICAL STORM FIONA DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL082010
1100 PM EDT MON AUG 30 2010

CONVECTION HAS INCREASED IN THE NORTHWESTERN PORTION OF FIONA THIS
EVENING. HOWEVER...OVERALL THE SYSTEM LOOKS FAIRLY DISORGANIZED
WITH JUST A FEW WEAK BANDING FEATURES. A NOAA/NTAS BUOY LOCATED
NEAR THE CENTER REPORTED A PRESSURE OF 1008 MB A FEW HOURS
AGO...WHICH IS ABOUT THE SAME PRESSURE AS BUOY 41041 MEASURED
EARLIER TODAY. THUS...THE INITIAL INTENSITY WILL REMAIN 35 KT FOR
THIS ADVISORY. GIVEN THE CURRENT DISHEVELED APPEARANCE OF FIONA...
ONLY A SLOW INCREASE IN STRENGTH IS FORECAST FOR THE NEXT DAY OR SO
WHILE THE TROPICAL CYCLONE MOVES OVER VERY WARM WATER AND LIGHT
SHEAR. AFTER THAT TIME...NORTHEASTERLY SHEAR INCREASES MARKEDLY AND
MAY HALT ANY FURTHER DEVELOPMENT...PLUS THE CYCLONE COULD BE MOVING
OVER COOLER WATERS THAT WERE UPWELLED BY EARL. MOST OF THE
MODELS...SAVE THE GFDL/GFDN...ARE IN CLOSE AGREEMENT WITH THIS
SCENARIO...AND THE OFFICIAL NHC INTENSITY FORECAST IS NEAR THE
PREVIOUS ONE BUT BELOW THE INTENSITY CONSENSUS. HOWEVER...I DO NOT
HAVE A LOT OF CONFIDENCE IN THE FORECAST AT THIS TIME. 

MICROWAVE AND SURFACE DATA SUGGEST THE CENTER IS MOVING 280/21.
FIONA SHOULD MOVE AROUND THE SOUTHWESTERN PERIPHERY OF A RIDGE OVER
THE CENTRAL ATLANTIC...EVENTUALLY TURNING TO THE WEST-NORTHWEST AND
NORTHWEST IN THE NEXT COUPLE OF DAYS.  THE TRACK MODELS ARE FAIRLY
WELL CLUSTERED...EXCEPT FOR THE ECMWF.  THAT MODEL IS ON THE LEFT
SIDE OF THE GUIDANCE ENVELOPE...PERHAPS BECAUSE IT SHOWS A DEEPER
FIONA RESPONDING TO STRONGER UPPER-LEVEL NORTHEASTERLY WINDS.
SINCE WE ARE NOT EXPECTING THAT SCENARIO...THE NHC FORECAST IS VERY
CLOSE TO THE PREVIOUS ONE...AND IS A LITTLE SOUTH OF THE MODEL
CONSENSUS.


FORECAST POSITIONS AND MAX WINDS

INITIAL      31/0300Z 15.1N  50.8W    35 KT
 12HR VT     31/1200Z 15.7N  54.0W    35 KT
 24HR VT     01/0000Z 16.9N  57.7W    40 KT
 36HR VT     01/1200Z 18.4N  60.6W    45 KT
 48HR VT     02/0000Z 20.5N  63.2W    45 KT
 72HR VT     03/0000Z 25.0N  67.0W    45 KT
 96HR VT     04/0000Z 28.0N  69.0W    45 KT
120HR VT     05/0000Z 29.0N  69.5W    45 KT

$$
FORECASTER BLAKE

Pues ha mejorado algo según el CNH:

000
WTNT43 KNHC 010900
TCDAT3
TROPICAL STORM FIONA DISCUSSION NUMBER   7
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL082010
500 AM AST WED SEP 01 2010

RECONNAISSANCE DATA...RADAR DATA FROM GUADELOUPE...AND SATELLITE
IMAGERY INDICATE FIONA HAS BECOME A LITTLE BETTER ORGANIZED THIS
MORNING. DEEP CONVECTION HAS INCREASED IN THE SOUTHERN SEMICIRCLE
AND THE CENTER HAS BECOME BETTER DEFINED IN RADAR IMAGERY AND IN
FLIGHT-LEVEL WIND DATA. THE MAXIMUM 850 MB FLIGHT-LEVEL WINDS
OBSERVED THUS FAR DURING THE CURRENT MISSION HAS BEEN 52 KT IN THE
NORTHEAST QUADRANT...WHICH EQUATES TO ABOUT A 42-KT SURFACE WIND.
THE LOWEST PRESSURES OBSERVED THUS FAR HAVE BEEN 1002 MB AT 0602Z
AND 1004 MB AT 0803Z. THE INITIAL INTENSITY IS SET AT 40 KT...WHICH
IS LOWER THAN THE 50-KT ADT INTENSITY ESTIMATE FROM UW-CIMSS.

THE INITIAL MOTION IS 290/12 KT USING RECON AND RADAR FIX POSITIONS.
FIONA APPEARS TO HAVE DECREASED ITS RATE OF CLOSURE ON EARL LOCATED
TO ITS NORTHWEST. OVER THE PAST 48 HOURS...THE DISTANCE BETWEEN
FIONA AND EARL HAS BEEN DECREASING BY ABOUT 100 NMI EVERY 12
HOURS...AND THE TWO CYCLONES ARE CURRENTLY ABOUT 750 NMI APART.
RIDDING BETWEEN THE TWO SYSTEMS HAS OBVIOUSLY INCREASED...WHICH HAS
RESULTED IN THE SIGNIFICANT DECREASE IN THE FORWARD SPEED OF FIONA
FROM MORE THAN 20 KT DOWN TO THE CURRENT 12 KT IN THE PAST 12
HOURS. THE POSSIBLE CAUSE OF THE RIDGING TO THE NORTHWEST OF FIONA
IS THE UPPER-LEVEL OUTFLOWS FROM BOTH CYCLONES CONVERGING TO THE
NORTHWEST OF FIONA. THIS RIDGING MAY ALLOW KEEP FIONA FROM
INTERACTING WITH THE LARGER CIRCULATION OF EARL LIKE MOST OF THE
GLOBAL MODELS HAVE BEEN FORECASTING THE PAST COUPLE OF DAYS. ALL OF
THE MODEL GUIDANCE...EXCLUDING NOGAPS...NOW SLOWS DOWN FIONA BY DAY
3...WITH THE CYCLONE POSSIBLY GETTING TRAPPED IN THE SUBTROPICAL
RIDGE. AS RESULT OF THESE NEW SCENARIO...A 96-HOUR POSITION HAS
BEEN ADDED AND DISSIPATION HAS BEEN DELAYED UNTIL 120 HOURS. IF
FIONA BECOMES A STRONGER SYSTEM THAN CURRENTLY FORECAST...THE
CYCLONE COULD SURVIVE AND END UP MAKING A CLOCKWISE LOOP OR EVEN
BECOME STATIONARY BY 120 HOURS. THE OFFICIAL FORECAST TRACK IS
SIMILAR TO THE PREVIOUS ADVISORY..EXCEPT SLOWER AT 48 HOURS AND
BEYOND...AND IS ALONG THE WESTERN EDGE OF THE GUIDANCE SUITE.

SOME DRY MID-LEVEL AIR APPEARS TO BE GETTING DRAWN INTO THE NORTHERN
QUADRANT OF THE FIONA...WHICH MAY BE RESPONSIBLE FOR THE LACK OF
SIGNIFICANT CONVECTION IN THAT REGION. HOWEVER...UPPER-LEVEL
OUTFLOW HAS IMPROVED SOME AND BECOME A LITTLE MORE CIRCULAR IN
APPEARANCE. THE OFFICIAL INTENSITY FORECAST WAS NUDGED UPWARD
SLIGHTLY FROM THE PREVIOUS ADVISORY...BUT IS LOWER THAN THE SHIPS
AND LGEM MODELS WHICH BRING FIONA UP TO A 60-KT SYSTEM BY 48
HOURS...AND MUCH LOWER THAN THE GFDL MODEL WHICH MAKES FIONA AN
85-KT HURRICANE AT THAT SAME TIME.


FORECAST POSITIONS AND MAX WINDS

INITIAL      01/0900Z 17.4N  60.2W    40 KT
 12HR VT     01/1800Z 18.9N  62.5W    45 KT
 24HR VT     02/0600Z 21.2N  64.7W    50 KT
 36HR VT     02/1800Z 23.5N  66.5W    50 KT
 48HR VT     03/0600Z 26.3N  67.3W    40 KT
 72HR VT     04/0600Z 29.2N  67.5W    35 KT
 96HR VT     05/0600Z 31.5N  67.0W    30 KT
120HR VT     06/0600Z...DISSIPATED

$$
FORECASTER STEWART

Señores, hay interacción con EARL... Aunque parece que hasta ahora esta interacción resulta en una disminución de velocidad de desplazamiento de FIONA. Adjunto imagen en que se les ve a ambos.

FIONA sigue luchando contra la cizalladura ambiental, pero a duras penas lo consigue... Su LLCC sigue expuesto, como le ocurría ayer, debido a la cizalladura moderada que le alcanza desde el N: