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Tropical Storm Frank Discussion Number 3
NWS National Hurricane Center Miami FL EP072022
400 PM CDT Tue Jul 26 2022
Convection near the center of Frank is struggling to organize, as
several bursts since the prior advisory have been stripped away
southwest of the center due to continued moderate northeasterly
vertical wind shear. Cirrus from a more recent convective burst is
currently covering the center. Today's scatterometer swaths just
clipped the far eastern edge of Frank's circulation, and while there
were some greater than 34-kt wind retrievals in ASCAT-B at around
1700 UTC, these values may have been rain contaminated, especially
compared to the much lower ASCAT-C values less than an hour prior.
Dvorak intensity estimates this afternoon were a consensus
T2.5/35-kt from TAFB, SAB, and ADT. The intensity will remain at 35
kt for this advisory.
The shear over Frank is not expected to abate for the next 36-48
hours, and in fact may increase a bit more as suggested by the
ECMWF-SHIPS guidance. Both the ECMWF and GFS simulated IR brightness
temperature also show convection continuing to be focused down-shear
of the low-level circulation during this time frame, limiting
intensification. One additional complicating factor is that another
system located west of Frank could also interact with the tropical
storm, though Frank should remain the dominant cyclone. Even after
the shear abates in around 3 days, it is unclear what type of storm
structure Frank will have at that time, and if it can take full
advantage of the more favorable environmental conditions. For these
reasons, the intensity forecast remains on the conservative side,
showing a pause in strengthening between 12-36 hours, and then
gradual intensification beginning afterwards. The latest intensity
forecast remains on the low end of the intensity guidance, and
remains closest to the LGEM model.
Frank continues to move just north of due west at 280/10 kt. This
general motion and heading should not change too much over the next
2-3 days as the storm remains steered by a large mid-level
subtropical ridge to its north. A weakness in the ridge thereafter,
as well as some possible interaction with the system west of Frank,
may allow the storm to gain more latitude thereafter. The track
guidance this cycle has shifted a bit north, and the latest track
forecast follows suit, located roughly between the HCCA and GFEX
aids.
FORECAST POSITIONS AND MAX WINDS
INIT 26/2100Z 11.8N 103.5W 35 KT 40 MPH
12H 27/0600Z 12.1N 104.9W 40 KT 45 MPH
24H 27/1800Z 12.5N 106.7W 40 KT 45 MPH
36H 28/0600Z 12.9N 108.5W 40 KT 45 MPH
48H 28/1800Z 13.4N 110.6W 45 KT 50 MPH
60H 29/0600Z 13.8N 112.6W 50 KT 60 MPH
72H 29/1800Z 14.3N 114.3W 60 KT 70 MPH
96H 30/1800Z 15.9N 117.1W 75 KT 85 MPH
120H 31/1800Z 18.4N 120.0W 75 KT 85 MPH
$$
Forecaster Papin
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