Post-Tropical Cyclone Miriam Discussion Number 31
NWS Central Pacific Hurricane Center Honolulu HI EP152018
1100 AM HST Sun Sep 02 2018
Under continued strong vertical wind shear of 45 to 55 kt, limited
amounts of deep convection have been displaced well to the north of
the exposed low-level circulation of Miriam for about 24 hours. HFO
and SAB deemed the system too weak to classify. JTWC gave a Dvorak
current intensity of 1.0/25 kt, and CIMSS ADT yielded an estimate of
1.5/25 kt. An overnight ASCAT pass from 0658Z showed a large area of
30 kt wind retrievals and one near 35 kt. Based on these inputs,
Miriam will be designated a post-tropical low with an intensity of
30 kt, and this will be the final advisory for this system.
Miriam is moving toward the northwest (310 degrees) at 10 kt. This
general motion will continue over the next day or so as a deep ridge
holds to the northeast and a mid- to upper-level trough remains
parked to the northwest. This trough will maintain strong
southwesterly vertical wind shear that will inhibit redevelopment
of the system, and the post-tropical remnant low should open into a
trough on Monday. The track and intensity forecasts are in the
middle of their guidance envelopes near TVCE and ICON,
respectively.
FORECAST POSITIONS AND MAX WINDS
INIT 02/2100Z 26.4N 144.6W 30 KT 35 MPH...POST-TROPICAL
12H 03/0600Z 27.3N 146.1W 25 KT 30 MPH...POST-TROP/REMNT LOW
24H 03/1800Z 28.2N 148.6W 25 KT 30 MPH...POST-TROP/REMNT LOW
36H 04/0600Z...DISSIPATED
$$
Forecaster Wroe
NWS Central Pacific Hurricane Center Honolulu HI EP152018
1100 AM HST Sun Sep 02 2018
Under continued strong vertical wind shear of 45 to 55 kt, limited
amounts of deep convection have been displaced well to the north of
the exposed low-level circulation of Miriam for about 24 hours. HFO
and SAB deemed the system too weak to classify. JTWC gave a Dvorak
current intensity of 1.0/25 kt, and CIMSS ADT yielded an estimate of
1.5/25 kt. An overnight ASCAT pass from 0658Z showed a large area of
30 kt wind retrievals and one near 35 kt. Based on these inputs,
Miriam will be designated a post-tropical low with an intensity of
30 kt, and this will be the final advisory for this system.
Miriam is moving toward the northwest (310 degrees) at 10 kt. This
general motion will continue over the next day or so as a deep ridge
holds to the northeast and a mid- to upper-level trough remains
parked to the northwest. This trough will maintain strong
southwesterly vertical wind shear that will inhibit redevelopment
of the system, and the post-tropical remnant low should open into a
trough on Monday. The track and intensity forecasts are in the
middle of their guidance envelopes near TVCE and ICON,
respectively.
FORECAST POSITIONS AND MAX WINDS
INIT 02/2100Z 26.4N 144.6W 30 KT 35 MPH...POST-TROPICAL
12H 03/0600Z 27.3N 146.1W 25 KT 30 MPH...POST-TROP/REMNT LOW
24H 03/1800Z 28.2N 148.6W 25 KT 30 MPH...POST-TROP/REMNT LOW
36H 04/0600Z...DISSIPATED
$$
Forecaster Wroe