百慕大东南热带风暴“费尔南德”(06L.Fernand) - 北上发展

ygsj24

260
WTNT41 KNHC 240232
TCDAT1

Tropical Storm Fernand Discussion Number   2
NWS National Hurricane Center Miami FL       AL062025
1100 PM AST Sat Aug 23 2025

Fernand is still trying to become better organized this evening. A
recent scatterometer pass around 0052 UTC depicted a peak wind speed
around 31 kt, southeast of the center. Latest satellite images show
there has been a recent burst in the last few hours over the
low-level center, although some of the outer rain bands have
diminished. Subjective and objective intensity estimates remain
around 35-40 kt. Using a blend of the estimates and recent satellite
trends, the intensity is held at 35 kt for this advisory.

The lastest motion is north-northeast at 015/14. Fernand is being
steered around the western edge of the subtropical ridge, which will
cause the storm to move north-northeastward during the next few
days. The system will then turn more northeastward within the flow
between the ridge and an approaching trough, and accelerate over the
north Atlantic. Model guidance is in fairly good agreement and the
latest NHC forecast is similar to the previous one, near the
corrected-consensus HCCA.

Fernand is within a favorable environment for intensification, with
warm sea surface temperatures and light wind shear. However, models
depict some mid-level dry air near it, which may hinder the
strengthening rate and structure. The intensity guidance has come
down slightly this cycle, and the latest NHC forecast follows those
trends with a peak intensity now at 55 kt, on the higher end of the
guidance envelope. The storm should begin to weaken as SSTs cool and
wind shear increases by day 3, and the system will likely become
post-tropical by day 4.


FORECAST POSITIONS AND MAX WINDS

INIT  24/0300Z 28.8N  61.2W   35 KT  40 MPH
12H  24/1200Z 30.6N  60.6W   40 KT  45 MPH
24H  25/0000Z 32.9N  59.7W   45 KT  50 MPH
36H  25/1200Z 35.0N  58.8W   50 KT  60 MPH
48H  26/0000Z 37.4N  57.5W   55 KT  65 MPH
60H  26/1200Z 40.0N  55.1W   50 KT  60 MPH
72H  27/0000Z 43.0N  51.7W   45 KT  50 MPH
96H  28/0000Z 49.0N  40.8W   40 KT  45 MPH...POST-TROP/EXTRATROP
120H  29/0000Z...DISSIPATED

$$
Forecaster Kelly

pocketbox

全球热带气旋监测公报
预报：钟晖子、刘涛  签发：董 林  2025 年 08 月 24 日 18 时
“费尔南德”向偏北方向移动

时        间:    24日14时（北京时，下同）

海        域:    北大西洋

命        名:    “费尔南德”， FERNAND

中心位置:    西经61.0度, 北纬29.1度

强度等级:    热带风暴

最大风力:    8级，18米/秒，相当于我国的热带风暴级

中心气压:    1010百帕

参考位置:    距离百慕大群岛东南方向约510公里

变化过程:    “费尔南德”强度变化不大

预报结论:    “费尔南德”将以每小时25公里左右的速度向偏北方向移动，强度逐渐加强。



图1 卫星红外监测图像（北京时间2025年8月24日14时00分）

ygsj24

643
WTNT41 KNHC 240834
TCDAT1

Tropical Storm Fernand Discussion Number   3
NWS National Hurricane Center Miami FL       AL062025
500 AM AST Sun Aug 24 2025

Convection associated with Fernand remains poorly organized this
morning, with a cluster near and just west of the center and a very
ragged outer band in the northern semicircle. The various
subjective and objective satellite intensity estimates remain in
the 35-40 kt range, and the initial intensity is held at 35 kt.

The initial motion is 015/13 kt. As mentioned previously, Fernand
is being steered around the western edge of the subtropical ridge,
which will cause the storm to move north-northeastward during the
next day or two. The system will then turn more northeastward and
accelerate within the mid-latitude westerly flow between the ridge
and an approaching trough. While the model guidance remains in good
agreement with this scenario, the guidance envelop has shifted a
little to the east since the previous advisory, Thus, the new
forecast track is a little east of the previous track.

Fernand should remain over warm sea surface temperatures and in
a light shear environment for the next 36 h or so. However,
mid-level dry air near the cyclone may slow the development. The
intensity guidance has again trended downward, and the new forecast
peak intensity of 50 kt is near the upper edge of the guidance.  
After 36 h, cooler water, increasing shear, and increased dry-air
entrainment should cause weakening, and Fernand is now forecast to
become post-tropical by 72 hr. The global models are in good
agreement that the system should degenerate to a trough by 96 h,
and the official forecast shows dissipation by that time.


FORECAST POSITIONS AND MAX WINDS

INIT  24/0900Z 29.7N  60.7W   35 KT  40 MPH
12H  24/1800Z 31.3N  60.1W   40 KT  45 MPH
24H  25/0600Z 33.6N  59.1W   45 KT  50 MPH
36H  25/1800Z 35.7N  57.9W   50 KT  60 MPH
48H  26/0600Z 38.2N  56.2W   50 KT  60 MPH
60H  26/1800Z 40.9N  53.6W   45 KT  50 MPH
72H  27/0600Z 44.3N  49.7W   40 KT  45 MPH...POST-TROP/EXTRATROP
96H  28/0600Z...DISSIPATED

$$
Forecaster Beven