老農民版夜神月

  一級颶風  
編號：08 E
名稱：Hilda

  基本資料  
擾動編號日期：2021 年 07 月 29 日 08 時
命名日期　　：2021 年 07 月 31 日 02 時
撤編日期　　：2021 年 08 月 06 日 20 時
登陸地點　　：無

  巔峰時期資料  
近中心最強風速 ：75  kt ( Cat.1 )
海平面最低氣壓 ：985 百帕

  擾動編號資料  
90E.INVEST.15kts.1009mb.9.5N.92W.

NHC：20%

2. Satellite imagery indicates that a broad area of low pressure has
formed several hundred miles offshore of the southwestern coast of
Mexico.  Environmental conditions are forecast to be conducive for
continued gradual development, and a tropical depression could form
this weekend or early next week while the system moves westward or
west-northwestward at 10 to 15 mph.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...medium...60 percent.

以上資料來自：NHC、颱風論壇整理製作

老農民版夜神月

NHC展望提升至Medium,40%

2. Satellite imagery indicates that a broad area of low pressure is
located several hundred miles offshore of the southwestern coast of
Mexico, and that the associated shower activity is showing signs
of organization.  Environmental conditions are forecast to be
conducive for continued gradual development, and a tropical
depression is likely to form this weekend or early next week while
the system moves westward or west-northwestward at 10 to 15 mph.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 5 days...high...70 percent.

老農民版夜神月

JTWC發布TCFA

WTPN22 PHNC 291330
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 90E)//
REF/A/JOINT TYPHOON WRNCEN PEARL HARBOR HI/290821Z JUL 21//
AMPN/REF IS TROPICAL CYCLONE FORMATION ALERT (WTPN21 PHNC 290830)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
120 NM EITHER SIDE OF A LINE FROM 11.7N 104.5W TO 12.3N 109.9W
WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
WINDS IN THE AREA ARE ESTIMATED TO BE 18 TO 23 KNOTS. METSAT
IMAGERY AT 291200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 12.0N 106.8W. THE SYSTEM IS MOVING WESTWARD AT 10 KNOTS.
2. REMARKS: AN AREA OF CONVECTION HAS PERSISTED NEAR 12.0N 106.8W,
APPROXIMATELY 1368 NM SOUTH-SOUTHEAST OF SAN DIEGO, CALIFORNIA.
ANIMATED ENHANCED INFRARED SATELLITE IMAGERY (EIR) AND A 290838Z
AMSR-2 MICROWAVE IMAGE DEPICT WEAK CONVECTIVE BANDING OVER THE
NORTHERN SEMI-CIRCLE WRAPPING INTO A CONSLIDATING LOW LEVEL
CIRCULATION (LLC). EIR AND MICROWAVE IMAGERY ALSO REVEAL MOST OF THE
CONVECTION DISPLACED IN THE SOUTHERN SEMI-CIRCLE. UPPER-LEVEL
ANALYSIS INDICTATES A FAVORABLE ENVIRONMENT WITH LOW VERTICAL WIND
SHEAR (5-10KT), GOOD EQUATORWARD OUTFLOW, AND WARM SEA SURFACE
TEMPERATURES (29-30C). MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED
AT 18 TO 23 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE
NEAR 1005 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT
TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
301330Z.
4. SEE REF A FOR DETAILS ON A TROPICAL CYCLONE FORMATION ALERT
LOCATED NEAR 13.8N 121.5W
//
NNNN

老農民版夜神月

NHC展望提升至80%,High

1. Showers and thunderstorms are gradually organizing in association
with an area of low pressure located about 500 miles south-southwest
of the coast of southwestern Mexico.  Environmental conditions are
conducive for continued development, and a tropical depression is
expected to form during the next day or two while the system moves
west-northwestward at 10 to 15 mph.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 5 days...high...90 percent.

老農民版夜神月

展望已提升至90%,可能即將獲得升格

1. Showers and thunderstorms are gradually becoming better organized
in association with an area of low pressure located about 600 miles
southwest of the coast of southwestern Mexico.  Environmental
conditions are conducive for continued development, and a tropical
depression or tropical storm is expected to form during the next
day or two while the system moves west-northwestward at 10 to 15
mph. For more information on this system, please see High Seas
forecasts issued by the NOAA Tropical Analysis and Forecast Branch.
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 5 days...high...90 percent.

老農民版夜神月

NHC直接升格TS,並命名Hilda,初報上望75節

000
WTPZ43 KNHC 302036
TCDEP3

Tropical Storm Hilda Discussion Number   1
NWS National Hurricane Center Miami FL       EP082021
300 PM MDT Fri Jul 30 2021

A pair of ASCAT passes from a few hours ago indicated that the area
of low pressure located about 800 miles south-southwest of the
southern tip of the Baja California peninsula has strengthened, and
is producing 35-40 kt winds on its east side.  In addition,
satellite images show a fairly persistent area of showers and
thunderstorms on the south side of the circulation and the center
appears to be fairly well defined in recent visible images.  Based
on these data, advisories are now being initiated on Tropical Storm
Hilda and the initial intensity is estimated to be 40 kt.

Hilda is moving westward at about 14 kt and is embedded in the flow
on the south side of a sprawling subtropical ridge that extends from
the south-central U.S. westward across the subtropical eastern
Pacific.  A general west-northwestward motion at about the same
forward speed is expected during the next day or two as the synoptic
pattern holds.  After that time, a decrease in forward speed is
predicted due to a combination of the subtropical ridge weakening
and the interactions with the areas of low pressure to the east and
west of Hilda.  The ECMWF is the slowest model at long range due to
it showing the most interaction with the low to Hildas east.  The
NHC track forecast lies generally near the model consensus and
roughly between the GFS and ECMWF models.

Hilda appears to be in generally conducive conditions for
strengthening with SSTs currently around 28 C, abundant mid-level
moisture, and fairly low wind shear. Given that these conditions are
expected to persist for another couple of days, steady strengthening
is forecast during that time period and Hilda is predicted to become
a hurricane in 24 to 36 hours.  Beyond a couple of days, however,
moderate easterly shear, progressively drier air, and decreasing
SSTs should end the strengthening trend and induce gradual weakening
of the cyclone.  The NHC intensity forecast lies near the middle of
the guidance envelope, closest to the intensity model consensus
IVCN.


FORECAST POSITIONS AND MAX WINDS

INIT  30/2100Z 12.1N 113.6W   40 KT  45 MPH
12H  31/0600Z 12.6N 115.4W   50 KT  60 MPH
24H  31/1800Z 13.2N 117.6W   60 KT  70 MPH
36H  01/0600Z 13.8N 119.7W   70 KT  80 MPH
48H  01/1800Z 14.3N 121.6W   75 KT  85 MPH
60H  02/0600Z 14.9N 123.1W   75 KT  85 MPH
72H  02/1800Z 15.3N 124.4W   70 KT  80 MPH
96H  03/1800Z 16.6N 126.4W   65 KT  75 MPH
120H  04/1800Z 18.3N 129.5W   55 KT  65 MPH

$$
Forecaster Cangialosi

t02436

底層風眼構建中，15Z強度已提升至TS上限的60節，巔峰上望85節。

029
WTPZ43 KNHC 311449
TCDEP3

Tropical Storm Hilda Discussion Number   4
NWS National Hurricane Center Miami FL       EP082021
800 AM PDT Sat Jul 31 2021

Hilda is strengthening quickly this morning.  Satellite images show
an eye feature trying to form, and convection has deepened and
become increasingly symmetric around the center.  The latest Dvorak
estimates supported raising the initial intensity to 55 kt at 12Z,
and since Hilda continues to organize, the initial intensity is set
a little higher at 60 kt for this advisory.  This makes Hilda just
below hurricane strength.

The current favorable environmental conditions of low wind shear,
high amounts of moisture, and warm SSTs should continue to allow
Hilda to intensify during the next day or so.  In addition, given
that Hilda now has a tight inner core, rapid intensification (RI) is
a decent possibility, and the SHIPS RI index now shows a 30 percent
chance of that occurring during the next 24 hours.  In a couple of
days, however, decreasing moisture and progressively cooler SSTs
should end the strengthening trend and gradually cause weakening
during the remainder of the forecast period.  The NHC intensity
forecast is above than the previous one in the short term and it
lies at the high end of the model guidance.  The long term forecast
is largely similar to the previous one and lies near the middle of
the guidance envelope.

Hilda is moving west-northwestward at 11 kt.  A subtropical ridge
should keep the storm on a general west-northwest heading during the
next several days, but there could be some interaction with Tropical
Depression Nine-E to the west and a low pressure area to the east
that could cause slow downs and wobbles in the future track.  There
is a fair amount of spread among the models, especially at the
longer range forecast times, but the latest consensus models are
right on top of the previous track. Therefore, the NHC track
forecast is largely just an update of the previous one.


FORECAST POSITIONS AND MAX WINDS

INIT  31/1500Z 13.7N 116.7W   60 KT  70 MPH
12H  01/0000Z 14.0N 118.2W   70 KT  80 MPH
24H  01/1200Z 14.4N 119.9W   85 KT 100 MPH
36H  02/0000Z 15.0N 121.5W   85 KT 100 MPH
48H  02/1200Z 15.5N 122.9W   85 KT 100 MPH
60H  03/0000Z 16.1N 124.3W   80 KT  90 MPH
72H  03/1200Z 16.9N 125.7W   70 KT  80 MPH
96H  04/1200Z 18.5N 128.6W   55 KT  65 MPH
120H  05/1200Z 19.3N 132.6W   45 KT  50 MPH

$$
Forecaster Cangialosi

老農民版夜神月

00Z升格C1,定強75KT