000
WTPZ43 KNHC 022042
TCDEP3
 
Tropical Storm Marie Discussion Number   7
NWS National Hurricane Center Miami FL       EP132026
200 PM MST Wed Sep 02 2026
 
Since the previous advisory, Marie has experienced bit of a hiccup
in its convective structure, with warming clouds tops near the
center aside from a recent burst wrapping around west of the
center. The most recent microwave pass from this morning showed a
banding type eye attempting to form, though it was struggling to
close off on its northwest side. In addition, there was an RCM-3
SAR pass earlier today with an interesting structure, showing a
small core, but with stronger winds occuring along the outer bands
of Marie's circulation. This structure hints that it might take
some time for the inner-core to fully consolidate. For now, the
18 UTC TAFB Dvorak satellite estimate was T3.5/55 kt, while the
objective intensity estimates range from 53 to 67 kt. Thus, the
initial intensity will remain 60 kt this advisory, keeping Marie
just shy of hurricane intensity.
 
Marie appears to be a little right of the prior forecast track, but
is still moving off to the northwest, with the estimated motion at
310/10 kt. Over the next several days, a narrow mid-level ridge
located to the north and northeast is expected to steer the tropical
cyclone generally off to the west-northwest, gradually slowing its
forward motion in the process as the ridge slowly weakens. Beyond 60
h, there continues to be significant cross-track spread that
develops among the model guidance, related to how much an amplified
mid-latitude trough, off the western United States coast, erodes
this ridge. For this cycle, some of the more reliable track aids,
ECMWF, Google DeepMind (GDMI), HCCA, actually show Marie turning
back westward in the day 4-5 time frame, as the ridge holds to the
north of the cyclone while the mid-latitude trough moves inland over
the western United States. However, there remain a minority of
solutions that show a more rightward track if the trough fully
erodes the ridge steering Marie. The NHC track forecast this cycle
is slightly right of the prior one for the first 48-60 h, following
the latest trends in the GDMI and HCCA aids, but now bends a little
more westward in days 4-5, also following trends in these aids.
 
Intensity-wise, the earlier SAR imagery in addition to a partial
ASCAT-C pass show Marie has a broad wind field with a
larger-than-normal radius of maximum wind. This could prevent more
rapid development over the next couple of days despite the favorable
environmental conditions. Thereafter, while sea-surface
temperatures (SSTs), diagnosed by SHIPS guidance between 27-28 C,
appear favorable, some of these waters were recently churned up by
the last tropical cyclone along this track (Iselle last week), and
the HAFS-A/B hurricane-regional models suggest the large wind field
of Marie could upwell some cooler waters underneath. Thus the latest
NHC intensity forecast shows a somewhat lower intensity than
earlier, peaking at 80 kt in the day 2-3 time frame. This intensity
forecast favors the hurricane-regional models over the latest SHIPS
guidance given the potential for ocean upwelling. Marie should be
crossing the 26 C SST isotherm after 72 h, and weakening is expected
to begin in earnest beyond this time period.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  02/2100Z 18.0N 112.5W   60 KT  70 MPH
 12H  03/0600Z 18.7N 113.5W   70 KT  80 MPH
 24H  03/1800Z 19.5N 115.0W   75 KT  85 MPH
 36H  04/0600Z 20.2N 116.5W   80 KT  90 MPH
 48H  04/1800Z 20.8N 117.8W   80 KT  90 MPH
 60H  05/0600Z 21.5N 119.1W   80 KT  90 MPH
 72H  05/1800Z 22.1N 120.3W   75 KT  85 MPH
 96H  06/1800Z 23.5N 122.5W   60 KT  70 MPH
120H  07/1800Z 23.7N 125.5W   50 KT  60 MPH
 
$$
Forecaster Papin