WTPZ43 KNHC 232038
TROPICAL STORM GEORGETTE DISCUSSION NUMBER 9
NWS NATIONAL HURRICANE CENTER MIAMI FL EP082016
200 PM PDT SAT JUL 23 2016
It appears that the shear is decreasing over Georgette, with the
outflow improving and the mid- and low-level centers coming into
better alignment. Visible imagery suggests a ragged eye trying to
develop, with a small mid-level eye noted in a 1539Z SSMIS overpass.
The initial intensity is set to 60 kt based on a blend of the latest
Dvorak estimates of T4.0/65 kt from TAFB and T3.5/55 kt from SAB.
This is also close to the latest UW-CIMSS SATCON estimate of 61 kt.
The initial 34-kt wind radii were adjusted based on data from a
1444Z pass of the RapidScat scatterometer on board the
International Space Station.
Georgette has 24-36 hours left before moving over SSTs below 26C,
and with the shear less than 10 kt some further intensification
seems likely. By 48 hours and beyond, weakening is forecast due to
cooler SSTs, some increase in shear, and a drier more stable
atmospheric environment. The new NHC intensity forecast is similar
to the last one and is near the high end of the guidance through 36
hours, but still below the HWRF. During the weakening phase the
official forecast is near or a little below IVCN and shows
Georgette becoming post-tropical by the end of the forecast period.
The initial motion is a little more westward (285/10), perhaps due
to the low- and mid-level centers coming closer together. Georgette
will be steered in the next 36 to 48 hours by a strong mid-level
ridge to the north. In 2 to 3 days an upper-level low slides north
of Georgette underneath the ridge, and the model guidance this
cycle shows a sharper poleward turn at days 3 and 4 as Georgette
feels more of a steering influence from this feature. A turn back
toward the west-northwest is expected by day 5 as Georgette weakens
and is steered by the low-level trade winds. The new NHC track
forecast is a little south of the previous one through 48 hours due
to the initial position and motion and is close to the consensus.
Later in the period the track has been shifted northward, but lies
on the left side of the guidance envelope near the GFS.
FORECAST POSITIONS AND MAX WINDS
INIT 23/2100Z 13.9N 122.3W 60 KT 70 MPH
12H 24/0600Z 14.5N 123.7W 65 KT 75 MPH
24H 24/1800Z 15.4N 125.4W 75 KT 85 MPH
36H 25/0600Z 16.4N 126.7W 75 KT 85 MPH
48H 25/1800Z 17.3N 127.8W 70 KT 80 MPH
72H 26/1800Z 18.6N 129.3W 55 KT 65 MPH
96H 27/1800Z 19.9N 131.2W 45 KT 50 MPH
120H 28/1800Z 21.3N 135.0W 35 KT 40 MPH...POST-TROPICAL