WTPZ42 KNHC 242044 RRA

TCDEP2



TROPICAL STORM FRANK DISCUSSION NUMBER  13

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP072016

300 PM MDT SUN JUL 24 2016



SOME IMPRESSIVE CHANGES HAVE OCCURRED WITH FRANK IN THE LAST SEVERAL

HOURS.  THE CLOUD STRUCTURE HAS EVOLVED FROM A SHEARED PATTERN INTO

A MORE BANDED CENTRAL DENSE OVERCAST CONFIGURATION.  A 1911Z GPM

MICROWAVE PASS SHOWS THE DEVELOPMENT OF A SHARP HOOKING FEATURE,

INDICATIVE OF A NOTABLE INCREASE IN ORGANIZATION.  ASCAT DATA CAUGHT

THE EASTERN SIDE OF THE CIRCULATION, WITH 55-KT MAXIMUM WINDS.  DUE

TO THE LOW BIAS OF THE INSTRUMENT AT THAT INTENSITY AND THE

INCREASING INNER-CORE STRUCTURE, THE INITIAL WIND SPEED IS SET TO

60 KT, NEAR THE TAFB CLASSIFICATION.



THE SHEAR APPEARS TO HAVE ABATED ENOUGH TO ALLOW FRANK TO INTENSIFY,

AND FRANK IS NOW FORECAST TO BECOME A HURRICANE BEFORE REACHING MORE

MARGINAL WATER TEMPERATURES.  THE BULK OF THE GUIDANCE IS ALSO

SHOWING A SIMILAR SOLUTION, ALTHOUGH THE COAMPS-TC AND THE GFDL DO

NOT SHOW ANY FURTHER STRENGTHENING.  FRANK IS EXPECTED TO BECOME A

REMNANT LOW IN 3 TO 4 DAYS WHILE IT MOVES OVER COOL 23 DEG C WATERS.

THE LATEST NHC INTENSITY FORECAST IS RAISED FROM THE PREVIOUS ONE,

CLOSE TO A BLEND OF THE SHIPS AND LGEM MODELS, WITH A BIT MORE

WEIGHT ON THE LATTER MODEL.



FRANK HAS SLOWED DOWN AND TURNED WESTWARD RECENTLY ACCORDING TO THE

MICROWAVE DATA, ALTHOUGH A LONGER TERM MOTION IS STILL

WEST-NORTHWESTWARD AT ABOUT 5 KT.  WHILE A RIDGE TO THE NORTH OF THE

STORM SHOULD STEER FRANK GENERALLY WESTWARD TO WEST-NORTHWESTWARD

FOR THE NEXT FEW DAYS, THERE IS A BIG DIFFERENCE EMERGING IN THE

LATEST GUIDANCE ON WHAT HAPPENS THEREAFTER.  IT SEEMS LIKE THE TRACK=