Tropical Storm KEVIN Forecast Discussion Number 15 2015-09-04 04:47:56

1441356476
Issued at 200 AM PDT FRI SEP 04 2015


000
WTPZ44 KNHC 040847
TCDEP4

TROPICAL STORM KEVIN DISCUSSION NUMBER  15
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP142015
200 AM PDT FRI SEP 04 2015

Kevin continues to produce a cluster of convection near the center
with cloud tops colder than -80C.  However, cirrus cloud motions in
infrared satellite imagery suggest that southerly vertical wind
shear is increasing over the cyclone, and an AMSU overpass at 0458
UTC suggests the low-level center is near the southern edge of the
convection.  The initial intensity remains 50 kt based on a blend
of intensity estimates from TAFB, SAB, and the CIMSS satellite
consensus technique.

The initial motion is 360/7.  Kevin should move generally northward
for the next 12-24 hours.  After that time, the dynamical guidance
suggests that the top and the bottom of the cyclone will part
company, with the mid- to upper-level center continuing northward
and the low-level center turning northwestward and then
west-northwestward. The new forecast track is similar to the
previous track through 48 hours and lies near the various consensus
models.  After that time, it is nudged a little northward due to a
northward shift in the track guidance.

The forecast track takes Kevin over decreasing sea surface
temperatures in an environment of increasing shear.  This
combination should cause steady weakening after 12 hours, with Kevin
forecast to weaken to a depression in about 36 hours an to
degenerate to a remnant low shortly thereafter.  The new intensity
forecast is in best agreement with the intensity consensus models.


FORECAST POSITIONS AND MAX WINDS

INIT  04/0900Z 20.2N 115.8W   50 KT  60 MPH
 12H  04/1800Z 21.2N 115.8W   50 KT  60 MPH
 24H  05/0600Z 22.2N 116.1W   40 KT  45 MPH
 36H  05/1800Z 22.9N 116.8W   30 KT  35 MPH
 48H  06/0600Z 23.4N 117.7W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  07/0600Z 24.0N 120.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  08/0600Z...DISSIPATED

$$
Forecaster Beven

http://www.nhc.noaa.gov/text/refresh/MIATCDEP4+shtml/040847.shtml

Tropical Storm FRED Forecast Discussion Number 22 2015-09-04 04:44:28

1441356268
Issued at 500 AM AST FRI SEP 04 2015


000
WTNT41 KNHC 040844
TCDAT1

TROPICAL STORM FRED DISCUSSION NUMBER  22
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL062015
500 AM AST FRI SEP 04 2015

Fred continues to produce bursts of deep convection near and east
of the center despite being affected by at least 30 kt of westerly
vertical wind shear and dry air entrainment.  Various subjective
and objective satellite intensity estimates range between 30 and 45
kt, and based on these data the initial intensity remains 35 kt.

Fred has continued to turn a little to the left and the initial
motion is now 275/9.  The cyclone or its remnants is expected to
recurve between the subtropical ridge to the east and a deep-layer
trough to the west during the forecast period.  While the track
guidance agrees with this scenario, there remain some difference in
the speed after recurvature between the slower GFS and the faster
ECMWF and UKMET. The new forecast track is an update of the previous
track with a small nudge to the east after 72 hours, and it splits
the difference between the faster and slower track guidance
mentioned above.

It may sound like a broken record, but Fred is expected to remain
in an environment of strong shear and dry air for the next 36-48
hours.  This should cause the system the degenerate into a remnant
low within 24 hours.  The dynamical models suggests that the shear
should decrease after 48 hours, although there is poor agreement
between them as to what the upper-level wind pattern will be near
Fred.  The GFS, UKMET, and Canadian models forecast Fred or its
remnants to intensify during that time, while the ECMWF and NAVGEM
models show little intensification.  Based on these forecasts and
the statistical guidance, the intensity forecast calls for Fred to
regain tropical cyclone status at around 96 hours, albeit with a
considerable amount of uncertainty.

FORECAST POSITIONS AND MAX WINDS

INIT  04/0900Z 22.1N  37.2W   35 KT  40 MPH
 12H  04/1800Z 22.3N  38.6W   30 KT  35 MPH
 24H  05/0600Z 22.6N  40.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
 36H  05/1800Z 23.2N  41.7W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  06/0600Z 24.1N  42.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  07/0600Z 27.0N  42.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  08/0600Z 29.5N  39.0W   30 KT  35 MPH...TROPICAL DEPRESSION
120H  09/0600Z 32.0N  36.5W   30 KT  35 MPH...TROPICAL DEPRESSION

$$
Forecaster Beven

http://www.nhc.noaa.gov/text/refresh/MIATCDAT1+shtml/040844.shtml