老農民版夜神月

NHC預測可能於24H內成為TC

INIT  31/1500Z 36.4N  43.2W   45 KT  50 MPH
12H  01/0000Z 35.9N  42.8W   50 KT  60 MPH
24H  01/1200Z 34.9N  42.4W   50 KT  60 MPH...TROPICAL CYCLONE
36H  02/0000Z 34.8N  41.2W   50 KT  60 MPH
48H  02/1200Z 35.6N  40.0W   50 KT  60 MPH
60H  03/0000Z 37.4N  39.1W   50 KT  60 MPH
72H  03/1200Z 39.4N  38.7W   45 KT  50 MPH
96H  04/1200Z 43.4N  37.3W   45 KT  50 MPH
120H  05/1200Z 47.2N  30.0W   40 KT  45 MPH...POST-TROPICAL

$$
Forecaster Latto

老農民版夜神月

NHC判定其18Z已再變性成為TS

AL, 21, 2021110118, , BEST, 0, 341N, 425W, 40, 996, TS,

老農民版夜神月

NHC預測3天內Wanda仍將保持TS強度於大西洋北部打轉
隨後將轉化為溫帶氣旋並趨向英國

000
WTNT41 KNHC 042042
TCDAT1

Tropical Storm Wanda Discussion Number  20
NWS National Hurricane Center Miami FL       AL212021
900 PM GMT Thu Nov 04 2021

Wanda continues to maintain bands of moderately deep convection
near the center, mainly over the northwestern semicircle.  The
cyclone also continues to show anticyclonic outflow.   However,
cold air clouds continue to wrap around the southern side of the
circulation, and in the big picture Wanda still gives the appearance
of being embedded in a larger-scale baroclinic low.  There has been
little change in the satellite intensity estimates since the
previous advisory, so the initial intensity is held at 40 kt.

Wanda is starting its anticipated turn and the initial motion is now
045/5.  During the next day or two,  a narrow mid-latitude ridge is
forecast to build to the northwest of the cyclone, and this should
cause Wanda to turn southeastward and southward by the 48 h point.  
By 60-72 h, another mid-latitude trough approaching Wanda should
cause a northeastward turn with acceleration, with this motion
persisting through the end of the forecast period.  The new guidance
again shows a little more southward motion by 48 h than the previous
guidance, and the new forecast track is adjusted a little southward
near that time.

Little change in strength is likely during the next 24 h as Wanda
remains over sea surface temperatures of near 20C.  By 48 h, the
southward motion brings the center over slightly warmer water, and
at that time the cyclone should interact with an upper-level low
that develops nearby.  This combination could allow some
strengthening, and the intensity forecast show modest strengthening
from 24-48 h.  Many of the guidance models continue to show more
strengthening and a higher intensity than the official forecast
between 48-72 h, and some adjustment may be needed to that part of
the forecast in later advisories if this trend persists.  Between
72-96 h, Wanda is expected to merge with a frontal system and
become extratropical over the northeastern Atlantic.


FORECAST POSITIONS AND MAX WINDS

INIT  04/2100Z 42.4N  39.2W   40 KT  45 MPH
12H  05/0600Z 41.9N  38.7W   40 KT  45 MPH
24H  05/1800Z 40.1N  38.2W   40 KT  45 MPH
36H  06/0600Z 38.5N  38.1W   45 KT  50 MPH
48H  06/1800Z 38.0N  37.7W   50 KT  60 MPH
60H  07/0600Z 39.2N  35.9W   50 KT  60 MPH
72H  07/1800Z 42.6N  32.2W   50 KT  60 MPH
96H  08/1800Z 49.0N  23.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
120H  09/1800Z 53.0N  12.5W   35 KT  40 MPH...POST-TROP/EXTRATROP

$$
Forecaster Beven

老農民版夜神月

NHC預測其於36小時內仍將於40N左右緩慢移動,至72小時方才轉化回溫帶氣旋

020
WTNT41 KNHC 051445
TCDAT1

Tropical Storm Wanda Discussion Number  23
NWS National Hurricane Center Miami FL       AL212021
300 PM GMT Fri Nov 05 2021

Wanda's cloud pattern has again changed little since the last
advisory, with bands of moderately deep convection currently
located mainly in the southern semicircle.  Just-received ASCAT
data indicates an area of 40-45 kt winds mainly west of the center,
and based on this the initial intensity is a possibly conservative
45 kt.  The ASCAT data also show that the wind field has expanded
on the west side, and the initial and forecast wind radii have thus
been modified.

The initial motion is now south-southeastward or 160/7 kt.  A
southward motion is forecast during the next 24 h as a mid-level
ridge builds to the north and west of the cyclone.  After that time,
a developing mid-latitude cyclone currently south of eastern Canada
will move close enough to break down the ridge and produce
southwesterly deep-layer flow around Wanda.  This should cause the
tropical cyclone to turn northeastward and accelerate, with a quick
northeastward motion continuing until Wanda dissipates.  The latest
track guidance is in good agreement, and the new forecast track lies
close to the various consensus models.

The southward motion should bring the center over slightly warmer
water during the next 24-36 h, and during this time Wanda should be
in an area of light to moderate shear inside of the circulation of a
nearby upper-level low.  This environment should allow Wanda to
maintain its strength and perhaps strengthen a little.  By 48 h, the
mid- latitude system approaching from the west should cause
increased shear, although the associated increased upper-level
divergence may offset any weakening caused by the shear.  Wanda is
forecast to merge with a frontal zone by 72 h, and by 120 h the
system is forecast to weaken to a tough to the south of a large
mid-latitude low over the northeastern Atlantic.  The new intensity
forecast has only minor adjustments from the previous forecast.


FORECAST POSITIONS AND MAX WINDS

INIT  05/1500Z 40.6N  37.8W   45 KT  50 MPH
12H  06/0000Z 39.1N  37.7W   45 KT  50 MPH
24H  06/1200Z 37.9N  37.7W   45 KT  50 MPH
36H  07/0000Z 38.2N  36.5W   45 KT  50 MPH
48H  07/1200Z 41.0N  33.1W   50 KT  60 MPH
60H  08/0000Z 45.4N  28.2W   50 KT  60 MPH
72H  08/1200Z 50.0N  22.6W   45 KT  50 MPH...POST-TROP/EXTRATROP
96H  09/1200Z 57.5N  12.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
120H  10/1200Z...DISSIPATED

$$
Forecaster Beven

老農民版夜神月

將達顛峰,隨後轉化為溫帶氣旋

201
WTNT41 KNHC 061442
TCDAT1

Tropical Storm Wanda Discussion Number  27
NWS National Hurricane Center Miami FL       AL212021
300 PM GMT Sat Nov 06 2021

The structure of Wanda has changed little since the last advisory,
with a band of convection near the center in the northern
semicircle and more isolated convective cells elsewhere near the
center.  The various objective and subjective satellite intensity
estimates range from 30-47 kt.  Given the spread and the unchanged
structure, the initial intensity is held at 45 kt.

The initial motion is 180/5 kt.  Satellite imagery shows a large
mid-latitude low pressure system approaching Wanda from the west and
northwest, which should cause the tropical cyclone to turn
northeastward during the next 12 h.  After that, Wanda is expected
to accelerate toward the northeast.  The current guidance is in
good agreement on the direction of motion, although it is a little
slower than the previous guidance.  The new forecast track is
similar to, but slightly slower than, the previous forecast.

Increasing upper-level divergence associated with the mid-latitude
low should allow Wanda to strengthen slightly during the next 24 h.
Afterwards, the cyclone is expected to merge with a cold front and
become an extratropical low.  The global models subsequently
forecast this low to weaken to a trough by 60 h, and the new
intensity forecast shows dissipation at that time.  Otherwise, there
are only minor adjustments to the previous intensity forecast.


FORECAST POSITIONS AND MAX WINDS

INIT  06/1500Z 37.0N  38.2W   45 KT  50 MPH
12H  07/0000Z 37.6N  36.8W   45 KT  50 MPH
24H  07/1200Z 40.5N  33.0W   50 KT  60 MPH
36H  08/0000Z 45.3N  26.7W   50 KT  60 MPH...POST-TROP/EXTRATROP
48H  08/1200Z 50.6N  18.1W   45 KT  50 MPH...POST-TROP/EXTRATROP
60H  09/0000Z...DISSIPATED

$$
Forecaster Beven

老農民版夜神月

NHC判定Wanda已併入鋒面,成為後熱帶氣旋

000
WTNT41 KNHC 071447
TCDAT1

Post-Tropical Cyclone Wanda Discussion Number  31
NWS National Hurricane Center Miami FL       AL212021
300 PM GMT Sun Nov 07 2021

Wanda is no longer generating deep convection in association with
its low-level circulation. In fact, most of the colder cloud tops
seen on satellite over the center right now are actually upper-level
cirrus associated with a cold frontal boundary part of a
larger mid-latitude cyclone southeast of Greenland. In addition, an
1156 UTC ASCAT-B pass over Wanda's circulation shows that the north
side is beginning to open up into a trough as the cold front is
encroaching on the system. These above factors suggest that Wanda is
no longer a tropical cyclone, and the system is now classified as a
post-tropical low as of this advisory. The winds remain 35-kt based
on the peak wind retrieval of 33-kt from the scatterometer data on
the southeast side of the circulation.

The system has been accelerating to the northeast with the latest
estimated motion at 045/22 kt. The post-tropical cyclone should
continue to accelerate to the northeast until it merges with
the baroclinic zone approaching it. A 12 hour point is provided for
continuity and to indicate the transition to an extratropical
cyclone, though its quite possible the system will be fully
absorbed by the frontal boundary by then. The track guidance at
12 hours is tightly clustered, and the NHC track forecast at that
time fame follows the consensus aids closely.

This is the last NHC advisory on Wanda.  Additional information on
this system can be found in High Seas Forecasts issued by Meteo
France under WMO header FQNT50 LFPW and available on the web at
www.meteofrance.com/previsions-meteo-marine/bulletin/grandlarge/
metarea2.


FORECAST POSITIONS AND MAX WINDS

INIT  07/1500Z 40.2N  33.5W   35 KT  40 MPH...POST-TROPICAL
12H  08/0000Z 43.5N  29.1W   35 KT  40 MPH...POST-TROP/EXTRATROP
24H  08/1200Z...DISSIPATED

$$
Forecaster Papin