WTPZ41 KNHC 100232 RRA

TCDEP1



TROPICAL STORM ADRIAN DISCUSSION NUMBER   2

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP012017

1000 PM CDT TUE MAY 09 2017



ALTHOUGH OUTER BANDING FEATURES HAVE WEAKENED SOMEWHAT SINCE THE

PREVIOUS ADVISORY, THE INNER-CORE CONVECTIVE PATTERN HAS IMPROVED,

INCLUDING THE POSSIBLE DEVELOPMENT OF A SMALL, MID-LEVEL EYE FEATURE

AS NOTED IN 0059Z SSMI/S MICROWAVE DATA. THE UPPER-LEVEL OUTFLOW IS

IMPROVING AND EXPANDING IN ALL QUADRANTS, EXCEPT TO THE EAST WHERE

IS BEING RESTRICTED BY UPPER-LEVEL EASTERLY FLOW. SATELLITE

CLASSIFICATIONS ARE A CONSENSUS T2.5/35 KT FROM TAFB AND SAB, SO THE

DEPRESSION HAS BEEN UPGRADED TO TROPICAL STORM STATUS. THIS MAKES

ADRIAN THE EARLIEST TROPICAL STORM TO FORM IN THE EASTERN NORTH

PACIFIC BASIN DURING THE SATELLITE ERA.



THE INITIAL MOTION ESTIMATE IS 290/06 KT. ADRIAN IS MOVING SLOWLY

WEST-NORTHWESTWARD ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYER

RIDGE LOCATED OVER THE CENTRAL AND SOUTHWESTERN GULF OF MEXICO. THE

GLOBAL AND REGIONAL MODELS ARE FAIR AGREEMENT ON THIS RIDGE PATTERN

REMAINING BASICALLY STATIC FOR THE NEXT 48-72 HOURS, SO LITTLE

CHANGE IN THE WEST-NORTHWESTWARD MOTION OF THE TROPICAL STORM IS

EXPECTED DURING THAT TIME. BY 72 HOURS AND BEYOND, THE RIDGE TO THE

NORTH OF ADRIAN IS FORECAST TO GRADUALLY WEAKEN AND EVENTUALLY BREAK

DOWN BY 120 HOURS AS THE LARGE-SCALE, HIGH-AMPLITUDE FLOW PATTERN

ACROSS THE UNITED STATES WEAKENS AND SHIFTS EASTWARD. THIS PATTERN

CHANGE IS EXPECTED TO RESULT IN WEAK SOUTHWESTERLY STEERING FLOW

DEVELOPING, CAUSING THE CYCLONE TO SLOW DOWN SIGNIFICANTLY AND TURN

NORTHEASTWARD. THE 12Z ECMWF MODEL RUN DOES NOT DEVELOP THE CYCLONE=