Tropical Storm SIMON Forecast Discussion
WTPZ44 KNHC 020837
TROPICAL STORM SIMON DISCUSSION NUMBER 3
NWS NATIONAL HURRICANE CENTER MIAMI FL EP192014
200 AM PDT THU OCT 02 2014
Satellite images indicate that curved banding features have become
better established during the last several hours, and the low-level
center is now estimated to be located beneath the deep convection.
Dvorak classifications from TAFB, SAB, and the University of
Wisconsin-CIMSS all support raising the initial wind speed to 35
kt, making the system Tropical Storm Simon. This is the 18th named
storm of the busy 2014 hurricane season in the east Pacific basin.
Simon is expected to strengthen during the next few days while the
storm remains over warm water and within a fairly low wind shear and
moist environment. The combination of an increase in southwesterly
shear and cooler water should stop the strengthening trend in about
3 days, and induce a gradual weakening. The NHC intensity forecast
is a little above the intensity model consensus, given the expected
favorable conditions during the next few days, leaning toward the
more aggressive SHIPS model.
Simon is moving west-northwestward at about 9 kt, and this general
motion is expected to continue for the next 2 to 3 days while the
storm is steered by mid-level ridging to its north and northeast.
The model guidance is in fair agreement during that time period,
and the NHC track forecast lies near the middle of the guidance
envelope. The guidance diverges significantly beyond that time
period, however, with many of the models showing a turn to the
north and then northeast toward large-scale troughing over the U.S.
Conversely, the ECMWF shows less interaction with the trough and
takes the storm farther west. The NHC track forecast lies on the
western side of the guidance envelope at days 4 and 5, similar to
the previous forecast, but confidence at the longer range is low at
FORECAST POSITIONS AND MAX WINDS
INIT 02/0900Z 18.1N 106.1W 35 KT 40 MPH
12H 02/1800Z 18.5N 107.2W 40 KT 45 MPH
24H 03/0600Z 18.9N 108.9W 50 KT 60 MPH
36H 03/1800Z 19.3N 110.6W 55 KT 65 MPH
48H 04/0600Z 19.9N 112.2W 60 KT 70 MPH
72H 05/0600Z 21.5N 114.7W 60 KT 70 MPH
96H 06/0600Z 23.2N 115.5W 50 KT 60 MPH
120H 07/0600Z 24.0N 115.5W 40 KT 45 MPH