6. AN ADDITIONAL PRODUCT...WITH WHICH USERS MAY BE LESS FAMILIAR...IS
THE TROPICAL CYCLONE UPDATE.  THE TROPICAL CYCLONE UPDATE IS A
BRIEF STATEMENT TO INFORM OF SIGNIFICANT CHANGES IN A TROPICAL
CYCLONE OR TO POST OR CANCEL WATCHES OR WARNINGS.  IT IS USED IN
LIEU OF OR TO PRECEDE THE ISSUANCE OF A SPECIAL ADVISORY PACKAGE. 
TROPICAL CYCLONE UPDATES...WHICH CAN BE ISSUED AT ANY TIME...CAN BE
FOUND UNDER WMO HEADER WTPZ61-65 KNHC...AND UNDER AWIPS HEADER
MIATCUEP1-5.