Tropical Cyclone Position Estimate  (Source: NHC wen site)

World Meteorological Organization (WMO) and AWIPS (in parenthesis) headers:
WTNT51-55 KNHC (MIATCEAT1-5) - Atlantic
WTPZ51-55 KNHC (MIATCEEP1-5) - E. Pacific (rarely issued)

Tropical Cyclone Position Estimates are issued between 2-hourly intermediate
public advisories whenever a tropical cyclone with a well-defined radar center
is within 200 nautical miles of land-based radar in the United States. These
estimates give the center location in map coordinates and distance and
direction from a well-known point.