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Tropical Storm Pablo Discussion Number 1
NWS National Hurricane Center Miami FL AL182019
500 PM AST Fri Oct 25 2019
High-resolution visible satellite imagery gave us a surprise today.
A tropical cyclone has formed within a larger extratropical cyclone
in the northeastern Atlantic. This is not unique and has occurred
several times in the past, primarily during the latter part of the
hurricane season. Pablo is a very small-scale tropical cyclone, but
ASCAT data clearly show a well-defined but small circulation with
40-kt winds embedded within the larger low. This is the intensity
assigned to the cyclone for this advisory. The cloud pattern
consists of an eye-type feature surrounded by a ring of deep
convection. Given the small size of the cyclone, and the baroclinic
environment, the intensity forecast is highly uncertain. At this
time, the NHC forecast calls for a small increase in the winds and
for the cyclone to become extratropical in about 36 hours. However,
this transition could occur sooner than anticipated.
Pablo is currently moving toward the east-southeast at about 9 kt
while embedded within the circulation of the larger extratropical
low. Pablo should then turn toward the northeast with some increase
in forward speed, as indicated by the multi-model consensus aids.
In fact, all the models are in very good agreement, and the NHC
forecast is in the middle of the guidance envelope.
Given that Pablo is embedded within a large extratropical low,
which itself is forecast to bring strong winds to the Azores, the
Portuguese Institute for the Sea and Atmosphere (IPMA) has included
the effects of this small cyclone in their products. Those products
already account for the strong winds and high waves.
FORECAST POSITIONS AND MAX WINDS
INIT 25/2100Z 35.8N 32.2W 40 KT 45 MPH
12H 26/0600Z 35.3N 30.7W 45 KT 50 MPH
24H 26/1800Z 36.3N 26.8W 45 KT 50 MPH
36H 27/0600Z 40.0N 23.5W 45 KT 50 MPH
48H 27/1800Z 43.0N 21.5W 40 KT 45 MPH...POST-TROP/EXTRATROP
72H 28/1800Z 46.5N 20.0W 40 KT 45 MPH...POST-TROP/EXTRATROP