El outflow de Igor está prduciendo cizalladura del norte de 40 nudos a Julia

JULIA IS MAINTAINING A CENTRAL DENSE OVERCAST FEATURE THAT IS
DISPLACED SLIGHTLY TO THE SOUTH-SOUTHEAST OF THE CENTER.

THE SYSTEM IS LIKELY TO EXPERIENCE
INCREASING NORTHERLY TO NORTHWESTERLY SHEAR ASSOCIATED WITH THE
MASSIVE UPPER-LEVEL OUTFLOW PATTERN OF HURRICANE IGOR.  GIVEN THE
HIGH AMOUNT OF SHEAR EXPECTED TO IMPACT JULIA...THE OFFICIAL
INTENSITY FORECAST SHOWS A SOMEWHAT FASTER RATE OF WEAKENING

FORECAST POSITIONS AND MAX WINDS

INITIAL      17/1500Z 24.2N  46.7W    75 KT
 12HR VT     18/0000Z 25.8N  48.8W    70 KT
 24HR VT     18/1200Z 28.3N  51.1W    65 KT
 36HR VT     19/0000Z 30.9N  52.1W    60 KT
 48HR VT     19/1200Z 33.2N  51.7W    50 KT
 72HR VT     20/1200Z 36.4N  48.5W    40 KT
 96HR VT     21/1200Z 40.0N  44.0W    30 KT
120HR VT     22/1200Z...DISSIPATED

$$
FORECASTER PASCH

000
WTNT42 KNHC 180831
TCDAT2
TROPICAL STORM JULIA DISCUSSION NUMBER  25
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL122010
500 AM AST SAT SEP 18 2010

STRONG NORTHERLY SHEAR CONTINUES TO WEAKEN JULIA.  SATELLITE IMAGES
SHOW THAT THE CENTER OF THE STORM IS PARTIALLY EXPOSED ON THE
NORTHWESTERN EDGE OF A BURST OF CONVECTION.  DVORAK CLASSIFICATIONS
ARE DROPPING QUICKLY...AND A BLEND OF THE T/CI NUMBERS FROM
TAFB/SAB AND ADT VALUES FROM UW-CIMSS GIVES AN INITIAL WIND SPEED
OF 50 KT. A STEADY DECREASE IN STRENGTH IS LIKELY WITH THE STRONG
SHEAR EXPECTED TO PERSIST.  JULIA SHOULD BECOME A REMNANT LOW BY 72
HOURS...IF NOT SOONER BECAUSE OF EXPECTED COOL SSTS.  THE NHC
FORECAST IS CLOSE TO THE SHIPS MODEL...AND IS BELOW MOST OF THE
GUIDANCE.  THE REMNANT LOW IS EXPECTED TO BE ABSORBED BY IGOR IN
ABOUT 96 HRS. 

THE INITIAL MOTION CONTINUES TO BEND A LITTLE TO THE RIGHT AND IS
NOW 320/16.  THE MODEL GUIDANCE IS TIGHTLY CLUSTERED ON A
NORTHWESTWARD TRACK TODAY...WITH A NORTHWARD TURN TOMORROW AS JULIA
MOVES AROUND A SUBTROPICAL RIDGE.  MOST OF THE GUIDANCE SUGGESTS
THAT JULIA WILL STAY FAR ENOUGH AWAY FROM IGOR THAT THE LARGER
HURRICANE WILL NOT HAVE AN IMMEDIATE IMPACT ON THE TRACK OF JULIA.
THE NHC FORECAST IS CLOSE TO THE PREVIOUS ONE...ON THE RIGHT EDGE
OF THE GUIDANCE ENVELOPE...AND NOT TOO FAR FROM THE GFS. 

THE WIND RADII HAVE BEEN ADJUSTED BASED ON AN EARLIER ASCAT PASS.

FORECAST POSITIONS AND MAX WINDS

INITIAL      18/0900Z 27.4N  50.1W    50 KT
 12HR VT     18/1800Z 29.5N  51.5W    45 KT
 24HR VT     19/0600Z 32.3N  52.1W    40 KT
 36HR VT     19/1800Z 34.5N  51.3W    35 KT
 48HR VT     20/0600Z 36.0N  49.0W    30 KT
 72HR VT     21/0600Z 39.5N  44.0W    25 KT...POST-TROP/REMNT LOW
 96HR VT     22/0600Z...ABSORBED BY IGOR

$$
FORECASTER BLAKE

000
WTNT42 KNHC 191458
TCDAT2
TROPICAL STORM JULIA DISCUSSION NUMBER  30
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL122010
1100 AM AST SUN SEP 19 2010

JULIA HAS HAD ANOTHER BURST OF DEEP CONVECTION OVER THE PAST SEVERAL
HOURS...AND SATELLITE INTENSITY ESTIMATES REMAIN AT T3.0/45 KT FROM
BOTH TAFB AND SAB.  THE INITIAL INTENSITY IS KEPT AT 45 KT FOR THIS
ADVISORY...BUT IT APPEARS THAT THE STORM IS AGAIN RUNNING INTO
STRONG SHEAR ASSOCIATED WITH OUTFLOW FROM HURRICANE IGOR AND SHOULD
WEAKEN SOON.  THE SHIPS AND LGEM MODELS SHOW FASTER WEAKENING THAN
THE DYNAMICAL GUIDANCE...INCLUDING THE GLOBAL MODELS WHICH SHOULD
HAVE A BETTER REPRESENTATION OF THE MID-LATITUDE SYNOPTIC PRESSURE
PATTERN.  THE OFFICIAL FORECAST IS NEAR OR JUST BELOW THE INTENSITY
CONSENSUS...AND INDICATES JULIA WEAKENING TO A TROPICAL DEPRESSION
OR REMNANT LOW IN 36-48 HOURS.

BASED ON RECENT MICROWAVE DATA AND VISIBLE SATELLITE IMAGERY...THE
CENTER OF JULIA HAS BEEN RELOCATED TO THE SOUTH...AND THE INITIAL
MOTION HAS VEERED QUICKLY TO 065 DEGREES AT 13 KT.  JULIA IS
EXPECTED TO CONTINUE MOVING AROUND THE NORTHWESTERN AND NORTHERN
SIDE OF A MID-LEVEL HIGH OVER THE NEXT COUPLE OF DAYS.  WITH THE
ADJUSTED INITIAL POSITION BEING FARTHER SOUTH...THE NEW TRACK
FORECAST IS SHIFTED SIGNIFICANTLY TO THE SOUTH OF THE PREVIOUS
FORECAST AND LIES ALONG THE SOUTHERN EDGE OF THE GUIDANCE ENVELOPE.

FORECAST POSITIONS AND MAX WINDS

INITIAL      19/1500Z 34.2N  50.3W    45 KT
 12HR VT     20/0000Z 34.9N  48.5W    35 KT
 24HR VT     20/1200Z 35.6N  46.5W    35 KT
 36HR VT     21/0000Z 36.2N  44.5W    30 KT...POST-TROP/REMNT LOW
 48HR VT     21/1200Z 37.5N  42.5W    25 KT...POST-TROP/REMNT LOW
 72HR VT     22/1200Z...DISSIPATED

$$
FORECASTER BERG

Es posible que esté habiendo una interacción, al menos, entre la vaguada en la que está embebida esa borrasca, y la nubosidad asociada a JULIA y/o sus masas de aire. De hecho, ayer comentaba en el hilo de modelos que el GFS mostraba una atmósfera muy dinámica e interesante para los próximos días. A seguir qué hacen IGOR y JULIA, porque no tengo tan claro que el primero vaya a absorber al segundo mientras hace transición extratropical...

ZCZC MIATCDAT2 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM JULIA DISCUSSION NUMBER  33
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL122010
500 AM AST MON SEP 20 2010

JULIA AGAIN PROVIDED A SURPRISE FOR A SECOND NIGHT IN A ROW WITH
STRONGER SURFACE WINDS MEASURED FROM THE ASCAT SCATTEROMETER THAN
WHAT WAS SUGGESTED FROM CONVENTIONAL SATELLITE IMAGERY USING THE
DVORAK TECHNIQUE.  THE 0046Z ASCAT PASS SHOWED MAXIMUM WINDS OF AT
LEAST 45 KT...DESPITE A FAIRLY DISHEVELED APPEARANCE TO THE DEEP
CONVECTION.  THE 0600Z TAFB AND SAB DATA-T DVORAK NUMBERS REMAIN AT
A 2.0...OR 30 KT.  THE INITIAL INTENSITY IS SET AT 40 KT...ASSUMING
SOME WEAKENING SINCE THE ASCAT PASS.

THE CENTER CONTINUES TO BE DISPLACED WEST OF THE LIMITED DEEP
CONVECTION DUE TO STRONG WESTERLY VERTICAL SHEAR INDUCED BY
EXTREMELY LARGE HURRICANE IGOR. THE INITIAL MOTION OF JULIA IS
ESTIMATED TO BE 65 DEGREES AT 8 KT...AND THE CYCLONE IS BEING
ADVECTED AROUND THE NORTHERN PERIPHERY OF THE DEEP LAYER
SUBTROPICAL RIDGE. THE CYCLONE SHOULD ACCELERATE SOME TOWARD THE
NORTH-NORTHEAST IN THE NEXT DAY OR SO. AROUND 36 HOURS...JULIA
SHOULD BECOME ABSORBED INTO THE CIRCULATION OF IGOR AS SHOWN BY
NEARLY ALL OF THE MODELS. HOWEVER...THE ECMWF MODEL KEEPS THE
CYCLONE FAR ENOUGH SOUTH OF IGOR TO PREVENT THE ABSORPTION.
INSTEAD...THE ECMWF MAINTAINS JULIA AS A SEPARATE CYCLONE FOR
SEVERAL MORE DAYS...THOUGH BECOMING EXTRATROPICAL ABOUT TWO DAYS
FROM NOW. THIS TRACK FORECAST GOES WITH THE CONSENSUS...MINUS THE
ECMWF...AND IS SLIGHTLY TO THE LEFT OF AND FASTER THAN THE PREVIOUS
ADVISORY.

AS JULIA SHOULD GRADUALLY ENCOUNTER SUB-26C WATER TEMPERATURES ALONG
WITH QUITE HOSTILE VERTICAL SHEAR...GRADUAL WEAKENING IS EXPECTED
FOR THE NEXT TWO DAYS UNTIL DISSIPATION.  THE INTENSITY FORECAST IS
BASED UPON THE MODEL CONSENSUS AND IS SLIGHTLY HIGHER THAN THE
PREVIOUS ADVISORY BECAUSE OF THE STRONGER INITIAL CYCLONE.

THE AFOREMENTIONED ASCAT PASS ALLOWED FOR AN ENLARGEMENT OF THE
TROPICAL STORM WIND RADII.

FORECAST POSITIONS AND MAX WINDS

INITIAL      20/0900Z 35.5N  47.9W    40 KT
 12HR VT     20/1800Z 36.1N  46.8W    35 KT
 24HR VT     21/0600Z 37.6N  45.3W    30 KT...POST-TROP/REMNT LOW
 36HR VT     21/1800Z 39.6N  43.5W    25 KT...POST-TROP/REMNT LOW
 48HR VT     22/0600Z...DISSIPATED

$$
FORECASTER LANDSEA/BRENNAN

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