WTPZ42 KNHC 220249 RRA

TCDEP2



TROPICAL STORM FRANK DISCUSSION NUMBER   2

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP072016

1000 PM CDT THU JUL 21 2016



CONVENTION AND MICROWAVE SATELLITE IMAGERY INDICATE THAT THE

CONVECTION ASSOCIATED WITH FRANK HAS BECOME BETTER ORGANIZED, WITH

A STRONG BURST OCCURRING JUST SOUTH OF THE CENTER.  BASED ON THE

PREVIOUS SCATTEROMETER DATA AND THE INCREASE IN ORGANIZATION, THE

INITIAL INTENSITY IS INCREASED TO 45 KT.



THE BEST ESTIMATE OF THE CURRENT MOTION IS 310/15, A LITTLE FASTER

THAN EARLIER.  FRANK IS LOCATED TO THE SOUTH OF A LARGE AND STRONG

MID-LEVEL ANTICYCLONE WHICH IS CENTERED OVER THE SOUTHERN PLAINS OF

THE UNITED STATES AND HAS A RIDGE EXTENDING WELL WESTWARD INTO THE

EASTERN PACIFIC.  THE DYNAMICAL MODELS FORECAST A SLIGHT

WEAKNESS IN THE RIDGE OVER THE NORTHEASTERN PACIFIC DURING THE NEXT

FEW DAYS.  THE ECMWF SHOWS A STRONGER WEAKNESS AND THUS FORECASTS

FRANK TO MOVE FARTHER NORTH, WHILE THE GFS KEEPS A STRONGER RIDGE

AND FORECASTS A MORE WESTWARD MOTION.  OVERALL, THE GUIDANCE

ENVELOPE HAS SHIFTED WESTWARD AWAY FROM THE COAST OF MEXICO DURING

THE LATER PART OF THE FORECAST PERIOD, AND THE OFFICIAL FORECAST

FOLLOWS SUIT.  HOWEVER, THERE IS STILL ENOUGH UNCERTAINTY THAT

INTERESTS IN THE SOUTHERN PORTION OF THE BAJA CALIFORNIA PENINSULA

SHOULD MONITOR THE PROGRESS OF FRANK.



FRANK IS EXPECTED TO REMAIN OVER WARM WATER FOR THE NEXT 3 DAYS OR

SO.  HOWEVER, EASTERLY SHEAR COULD INHIBIT INTENSIFICATION,

ESPECIALLY IF THE STRONGER UPPER-LEVEL WINDS FORECAST BY THE ECMWF

VERIFY. THE NEW INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS

FORECAST IN SHOWING STRENGTHENING THROUGH 72 HOURS, AND LIKE THE=