佛得角以西热带风暴“洛伦佐”(12L.Lorenzo) - 逐渐北上

yhh

97L INVEST 251012 0000 8.1N 31.7W ATL 25 1008

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1. Eastern and Central Tropical Atlantic:
A tropical wave located several hundred miles southwest of the Cabo
Verde Islands continues to produce a large and persistent area of
disorganized showers and thunderstorms.  Environmental conditions
appear conducive for some development of this system, and a tropical
depression could form next week while moving west-northwestward to
northwestward at 15 to 20 mph across the central tropical Atlantic.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 7 days...medium...50 percent.

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ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Sun Oct 12 2025

For the North Atlantic...Caribbean Sea and the Gulf of America:

1. Eastern and Central Tropical Atlantic (AL97):
A tropical wave located well to the southwest of the Cabo Verde
Islands continues to produce a large area of disorganized showers
and thunderstorms. Environmental conditions appear conducive for
some development of this system during the next few days, and a
tropical depression could form during the early or middle part of
this week while it moves to the west-northwest or northwest at 15 to
20 mph across the central tropical Atlantic.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 7 days...medium...50 percent.



Forecaster Reinhart

ygsj24

000
ABNT20 KNHC 122335
TWOAT

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Sun Oct 12 2025

For the North Atlantic...Caribbean Sea and the Gulf of America:

Central Tropical Atlantic (AL97):
Showers and thunderstorms have increased in association with a
small area of low pressure located about 900 miles west-southwest of
the Cabo Verde Islands.  Environmental conditions are forecast to
become more favorable for further development of this system during
the next few days, and a tropical depression is likely to form by
the middle part of this week while it moves to the west-northwest
then northwest at 15 to 20 mph across the central tropical Atlantic.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 7 days...high...70 percent.

$$
Forecaster Blake

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ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Mon Oct 13 2025

For the North Atlantic...Caribbean Sea and the Gulf of America:

1. Central Tropical Atlantic (AL97):
Showers and thunderstorms continue to increase near and just east of
a small area of low pressure located more than 900 miles west of the
Cabo Verde Islands. In addition, recent satellite wind data
indicates the system is also producing tropical-storm force winds,
primarily to the east of its center. Environmental conditions are
forecast to become more favorable for further development over the
next couple of days and a tropical storm is likely to form by the
early to middle portion of this week as the system moves
west-northwest to northwest at 15 to 20 mph across the central
tropical Atlantic. For more information on this system, including
gale warnings, please see High Seas Forecasts issued by the National
Weather Service.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 7 days...high...80 percent.



High Seas Forecasts issued by the National Weather Service
can be found under AWIPS header NFDHSFAT1, WMO header FZNT01
KWBC, and online at ocean.weather.gov/shtml/NFDHSFAT1.php


Forecaster Papin

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Special Message from NHC        Mon, 13 Oct 2025 08:11:32 +0000  
NHC will initiate advisories on Tropical Storm Lorenzo (formerly AL97), located over the central tropical Atlantic, at 500 AM AST (0900 UTC).

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WTNT42 KNHC 130855
TCDAT2

Tropical Storm Lorenzo Discussion Number   1
NWS National Hurricane Center Miami FL       AL122025
500 AM AST Mon Oct 13 2025

The area of low pressure we have been monitoring over the last day
or two (AL97) has become better organized this morning. After
spending most of yesterday as an exposed low-level swirl, tonight a
large burst of deep convection with cloud top temperatures below
-80C has formed near and just east of the center. An earlier ASCAT-C
pass clipped the eastern side of the system, showing that it was
already producing tropical-storm-force winds, with a peak derived
wind of 36 kt. A pair of AMSR2 and GMI microwave passes at 04-06 UTC
near the system also showed the improved structural organization
under the cirrus. The subjective 06 UTC Dvorak fix from TAFB was
T2.5/35 kt, and the satellite presentation has only grown more
impressive since that time, with the convective cloud tops taking a
distinct comma shape pattern. Thus, advisories are being initiated
on Tropical Storm Lorenzo this morning, with an initial intensity
of 40 kt, assuming a little undersampling from the earlier
scatterometer wind data.

The initial motion is a somewhat uncertain 305/15 kt, a little
slower than the center being tracked earlier, potentially due to the
large convective burst tugging at the center. This general
northwestward motion with some additional slowdown is anticipated
today as Lorenzo approaches a weakness in the subtropical ridging  
produced by an upper-level trough in the path of the tropical
cyclone. This trough is expected to fracture and shift to the
southwest of the system, and Lorenzo should turn northward between
this feature and the eroded mid-level ridge centered over the Cabo
Verde Islands. Ultimately, this ridge should result in the cyclone
recurving to the northeast around it, as it comes under influence of
broad-scale mid-latitude westerly flow. The initial NHC track
forecast is in pretty good agreement with a fairly tightly clustered
track guidance envelope, and is roughly a blend of the HCCA and
Google DeepMind guidance this cycle, a little east of the overall
track envelope.

While Lorenzo's structure on satellite imagery has improved, it is
still currently experiencing about 25-30 kt of southwesterly
vertical wind shear. However, both the GFS and ECMWF-based SHIPS
guidance suggests this shear will soon lessen to less than 10 kts in
24-48 hours. Ordinarily this would lead to strengthening given the
sufficently warm 27-28 C ocean temperatures, but at the same time,
environmental mid-level relatively humidity is also expected to dry
substantially as the storm interacts with the upper-level trough
ahead of it. This trough could also still produce some residual
mid-level shear undercutting the outflow layer. The overall guidance
is not that enthusiastic about Lorenzo's intensity prospects, but it
is worth noting there is quite a bit of spread in both the ECMWF and
Google DeepMind ensemble members, ranging from a very weak tropical
cyclone to a category 2 hurricane. The initial NHC intensity
forecast will try to split the difference, showing little change in
strength in the short-term while the shear remains high, and then
just gradual intensification afterwards. This is higher than the
majority of the hurricane-regional model guidance this cycle, but
under the Google DeepMind ensemble mean and HWRF model.


FORECAST POSITIONS AND MAX WINDS

INIT  13/0900Z 14.2N  40.3W   40 KT  45 MPH
12H  13/1800Z 15.0N  41.7W   40 KT  45 MPH
24H  14/0600Z 16.2N  43.4W   40 KT  45 MPH
36H  14/1800Z 18.0N  44.4W   45 KT  50 MPH
48H  15/0600Z 20.1N  44.7W   50 KT  60 MPH
60H  15/1800Z 22.4N  44.2W   55 KT  65 MPH
72H  16/0600Z 25.1N  42.6W   60 KT  70 MPH
96H  17/0600Z 30.9N  36.9W   55 KT  65 MPH
120H  18/0600Z 33.2N  29.6W   45 KT  50 MPH

$$
Forecaster Papin

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WTNT42 KNHC 131453
TCDAT2

Tropical Storm Lorenzo Discussion Number   2
NWS National Hurricane Center Miami FL       AL122025
1100 AM AST Mon Oct 13 2025

Lorenzo has maintained a large area of convection with cold cloud
tops, although the latest GOES-19 1-minute visible satellite images
suggest that the low-level center is near the southwestern edge of
this convection, which makes sense due to the strong southwesterly
wind shear over the cyclone.  Overall, Lorenzo's structure hasn't
changed much over the past 6 hours.  However, a timely recent ASCAT
pass shows a large area of 40-45 kt winds mainly in the northeast
quadrant, so the initial intensity is increased to 45 kt, which is
slightly above the latest objective current satellite intensity
estimates from UW-CIMSS.

The initial motion estimate is northwestward, or 310 degrees at 14
kt.  Lorenzo is near the southwestern periphery of a mid-level high
centered near the Cabo Verde Islands.  Farther northwest, a mid- to
upper-level trough is acting to erode the subtropical ridge.  This
trough is expected to fracture and shift to the southwest of the
system, and Lorenzo should turn northward on Tuesday between this
feature and the eroded mid-level ridge centered over the Cabo Verde
Islands.  Lorenzo is forecast to recurve northeastward on Wednesday
as the cyclone comes under the influence of broad-scale mid-latitude
westerly flow.  If Lorenzo is still alive by Friday, it could
approach a weakness in steering flow, with mid- to upper-level
ridging possibly centered to the north or northeast of the cyclone,
so the track forecast shows a slowdown with a turn to the east in
4-5 days.  The track guidance is in good agreement through the 72
hour point, but spread increases significantly after that time.  The
new NHC track forecast is slightly west of the previous NHC
prediction through hour 60, and lies close to the HFIP Corrected
Consensus (HCCA) during that time period.  At Day 5, the new NHC
forecast is south of the previous prediction.

Lorenzo continues to experience about 25 kt of southwesterly wind
shear, although the shear is forecast to decrease significantly
later today, and relatively light shear is anticipated from tonight
through Thursday.  Ordinarily, this would lead to strengthening
given the sufficently warm 27-28 C ocean temperatures, but at the
same time, environmental mid-level relatively humidity is also
expected to decrease substantially as the storm interacts with the
upper-level trough ahead of it.  This trough could also still
produce some residual mid-level shear undercutting the outflow
layer.  Most of the intensity guidance is not that enthusiastic
about Lorenzo's prospects, but there are a couple of ECMWF ensemble
members and a handful of Google DeepMind ensemble members that make
Lorenzo a hurricane.  The NHC intensity forecast is unchanged from
the previous advisory other than the slightly stronger initial
intensity, and is near the high end of the intensity guidance suite,
showing little change in strength in the short-term, and then
gradual intensification afterwards. The NHC intensity forecast is
still generally higher than the HCCA, HAFS, and the intensity
consensus.  There is some possibility that the aforementioned dry
air could cause Lorenzo to dissipate before the end of the 5-day
period, as suggested by some of the global and hurricane regional
models, but the NHC forecast maintains it as a tropical storm.


FORECAST POSITIONS AND MAX WINDS

INIT  13/1500Z 14.8N  41.2W   45 KT  50 MPH
12H  14/0000Z 15.6N  42.7W   45 KT  50 MPH
24H  14/1200Z 17.2N  44.1W   45 KT  50 MPH
36H  15/0000Z 19.2N  44.9W   45 KT  50 MPH
48H  15/1200Z 21.4N  44.9W   50 KT  60 MPH
60H  16/0000Z 23.9N  43.5W   55 KT  65 MPH
72H  16/1200Z 26.7N  41.2W   60 KT  70 MPH
96H  17/1200Z 31.4N  34.4W   55 KT  65 MPH
120H  18/1200Z 31.8N  29.8W   45 KT  50 MPH

$$
Forecaster Hagen