[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT45 KNHC 121445
TCDAT5

Tropical Storm Theta Discussion Number  11
NWS National Hurricane Center Miami FL       AL302020
300 PM GMT Thu Nov 12 2020

Although the cloud top temperatures across the broad comma-shaped
convective shield have warmed this morning, there is some new
convection that has been developing nearer to Theta's center over
the past few hours. Unfortunately, the scatterometer passes this
morning missed sampling the winds near the center of the cyclone.
However, the partial ASCAT-A overpass showed that 45 kt winds are
occurring nearly 100 n mi to the southwest of the center of Theta.
Therefore it is assumed that stronger winds are still occurring
closer to the center of the cyclone, and the initial intensity is
being held at 55 kt.

Theta has now turned to the right, and the initial motion is 080/10
kt. For about the next 36 h, the cyclone is expected to continue
moving just north of east around the north side of a mid-level
ridge. A slower east-southeastward motion is expected from 36-72 h
as the mid-level ridge to the south weakens and mid- to upper-level
northerly flow moves over Theta.  After 72 h, Theta or its
remnants are expected to turn northeastward or northward and
accelerate in the low-level flow ahead of an approaching deep-layer
mid-latitude cyclone over the northeastern Atlantic. The latest
track forecast is little changed from the previous one and is near
the multi-model consensus tracks.

The shear across Theta is expected to relax somewhat over the day or
so, while moving over cooler waters. The counteracting effects
should allow the cyclone to maintain its intensity. By this weekend,
strong northerly shear is expected to impact Theta, while stable air
gets entrained into its circulation. This should cause the cyclone
to weaken, with the system likely degenerating into a remnant low by
Sunday. The latest NHC intensity forecast is just slightly above the
guidance through 60 h, and is near the various consensus models
thereafter.


FORECAST POSITIONS AND MAX WINDS

INIT  12/1500Z 31.6N  28.8W   55 KT  65 MPH
 12H  13/0000Z 31.7N  27.0W   55 KT  65 MPH
 24H  13/1200Z 31.8N  24.7W   55 KT  65 MPH
 36H  14/0000Z 31.8N  22.6W   55 KT  65 MPH
 48H  14/1200Z 31.5N  21.0W   50 KT  60 MPH
 60H  15/0000Z 31.2N  20.2W   40 KT  45 MPH
 72H  15/1200Z 31.1N  19.6W   30 KT  35 MPH...POST-TROP/REMNT LOW
 96H  16/1200Z 32.7N  19.2W   30 KT  35 MPH...POST-TROP/REMNT LOW
120H  17/1200Z 37.6N  17.4W   30 KT  35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Latto
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