t02436

NHC 17Z將評級提升至High

1. Showers and thunderstorms associated with a low pressure system
centered about 850 miles southwest of the southern tip of the
Baja California peninsula continue to increase in organization.
Environmental conditions are conducive for development, and a
tropical depression is likely to form by late Sunday or early Monday
while the low  moves toward the west-northwest at 10 to 15 mph.
* Formation chance through 48 hours...high...80 percent
* Formation chance through 5 days...high...90 percent

美國海軍發布TCFA

t02436

NHC於1630Z升格09E，不看好有高強度的發展
另外趕在這個月過完之前升格，也平了1985年的紀錄

00
WTPZ44 KNHC 311622
TCDEP4

TROPICAL DEPRESSION NINE-E SPECIAL DISCUSSION NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP092016
930 AM PDT SUN JUL 31 2016

The first visible satellite images this morning indicate that a
well-defined center has formed in association with the area of low
pressure located well southwest of Mexico.  This, along with the
increase in convective organization, supports classifying this
system as a tropical cyclone.  A 1401Z SSMIS overpass indicated that
the low-level center was located beneath the convective canopy, and
the initial intensity is set to 30 kt based on the latest Dvorak
estimates from TAFB and SAB.

The cyclone is currently situated over waters of 27-28C and the
shear is expected to remain relatively low, so gradual strengthening
is forecast through the first 48 hours.  Later in the period, the
cyclone will move over cooler waters and into a drier and more
stable thermodynamic environment, which should result in gradual
weakening to remnant low status.  The NHC intensity prediction is a
little above the latest intensity consensus, but not as high as the
HWRF and COAMPS-TC models.  During the weakening phase, the NHC
forecast is below the SHIPS model and the intensity consensus.

The initial motion estimate is a somewhat uncertain 295/08.
However, the track forecast reasoning appears relatively
straightforward, as a mid-level ridge is expected to build westward
to the north of the cyclone through the forecast period.  This
should result in a west-northwestward heading, with a bit of a
westward bend in the track at days 4 and 5 as the shallow cyclone
comes under the influence of the low-level trade winds.  The NHC
track forecast is close to the middle of the guidance envelope near
the multi-model consensus.

This marks the formation of the eighth tropical cyclone in the basin
in July, tying the record set in July of 1985.

FORECAST POSITIONS AND MAX WINDS

INIT  31/1630Z 14.2N 120.5W   30 KT  35 MPH
12H  01/0000Z 14.9N 121.9W   35 KT  40 MPH
24H  01/1200Z 15.7N 123.9W   40 KT  45 MPH
36H  02/0000Z 16.6N 126.1W   45 KT  50 MPH
48H  02/1200Z 17.8N 128.7W   50 KT  60 MPH
72H  03/1200Z 20.3N 134.4W   40 KT  45 MPH
96H  04/1200Z 21.5N 139.5W   30 KT  35 MPH...POST-TROP/REMNT LOW
120H  05/1200Z 22.5N 144.5W   25 KT  30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Brennan