Eastern Pacific: Alvin and Barbara

On Alvin:

TROPICAL DEPRESSION CENTER LOCATED NEAR 13.4N 114.6W AT 30/1500Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 300 DEGREES AT 3 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1005 MB
MAX SUSTAINED WINDS 30 KT WITH GUSTS TO 40 KT.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 13.4N 114.6W AT 30/1500Z
AT 30/1200Z CENTER WAS LOCATED NEAR 13.3N 114.5W

FORECAST VALID 31/0000Z 13.6N 115.1W
MAX WIND 30 KT...GUSTS 40 KT.

On Barbara:

THE TROPICAL CYCLONE REMAINS NEARLY STATIONARY. WATER VAPOR IMAGERY
INDICATES THAT A LARGE MID- TO UPPER-LEVEL TROUGH IS DEVELOPING OVER
MEXICO AND THE WESTERN GULF OF MEXICO...WITH A LARGE MID/UPPER-
LEVEL RIDGE OVER THE PACIFIC WEST OF THE TROUGH. THE IMAGERY ALSO
SHOWS MID-LEVEL NORTHERLIES ABOUT TO IMPINGE ON THE CIRCULATION.
IN THE SHORT TERM...THIS SHOULD RESULT IN A SOUTHWARD DRIFT AWAY
FROM THE MEXICAN COASTLINE...AND MODEL GUIDANCE IS IN GOOD
AGREEMENT ON THIS FOR THE FIRST DAY OR TWO OF THE FORECAST. AFTER
THAT...HOWEVER...THERE IS A GREAT DEAL OF UNCERTAINTY AS TO WHETHER
BARBARA WILL BE STEERED NORTHEASTWARD AHEAD OF THE GULF TROUGH OR
SLIDE WESTWARD AS THE TROUGH LIFTS OUT AND RIDGING BUILDS BEHIND
IT. IN THE FORMER CAMP ARE THE GFS AND ECMWF...WHILE A MORE
WESTWARD TRACK IS INDICATED BY THE GFDL...UKMET...AND NOGAPS.
INTERESTINGLY...THE ECMWF ENSEMBLES ARE PRETTY MUCH SPLIT BETWEEN
THESE TWO OPTIONS. THE OFFICIAL FORECAST...ADMITTEDLY LOW
CONFIDENCE...CONTINUES TO FAVOR THE MORE WESTWARD SCENARIO.

THE INTENSITY FORECAST IS DIFFICULT AS WELL. THE MID-LEVEL
NORTHERLIES APPROACHING THE CYCLONE WILL ADVECT SOME DRY AIR INTO
THE CIRCULATION AND INCREASE THE VERTICAL SHEAR. CONSEQUENTLY...
BARBARA COULD STRUGGLE IN THE SHORT RUN. OVERALL...HOWEVER...
CONDITIONS APPEAR FAVORABLE FOR DEVELOPMENT...WITH VERY WARM WATERS
AND GOOD UPPER OUTFLOW.

FORECAST POSITIONS AND MAX WINDS

INITIAL 30/1500Z 14.2N 97.3W 35 KT
12HR VT 31/0000Z 13.9N 97.2W 35 KT
24HR VT 31/1200Z 13.4N 97.1W 40 KT
36HR VT 01/0000Z 13.0N 97.0W 50 KT
48HR VT 01/1200Z 13.0N 96.8W 60 KT
72HR VT 02/1200Z 13.5N 96.5W 70 KT
96HR VT 03/1200Z 15.0N 97.5W 75 KT
120HR VT 04/1200Z 16.5N 100.0W 70 KT

Barbara should be the more interesting to watch. We shall see how well the forecast predicts this storm, as they think it will be a Cat 1 hurricane on June 2nd.