EPAC: BLANCA - Post-Tropical

[Kingarabian]

TXPZ29 KNES 011202
TCSENP
A. 02E (BLANCA)
B. 01/1130Z
C. 13.8N
D. 108.7W
E. ONE/GOES-W
F. T4.5/4.5
G. IR/EIR
H. REMARKS...SYSTEM DISPLAYS AN EYE LIKE FEATURE WITH MG FOR EYE TEMP
AND BLACK AS THE SURROUNDING RING TEMP EMBEDDED IN LG RESULTING IN A DT
OF 5.0 FOR EYE PATTERN. MET AND PT ARE 4.0. FT IS BASED ON CONSTRAINTS
OF FT CANNOT BE GREATER THAN 1 OVER 6 HOURS FROM PREVIOUS FT.
I. ADDL POSITIONS
NIL

...PATEL

Well. This was IR at the time of the fix:

[cycloneye]

Going down from here.

EP, 02, 2021060112, , BEST, 0, 146N, 1098W, 50, 999, TS, 50, NEQ, 20, 0, 0, 0, 1010, 120, 20, 0, 0, E, 0, , 0, 0, BLANCA, M

[JW-_-]

SAB, MP, IM, 1, 4545 /////, , , GOES17, LLCC, T, DT=5.0 BO EYE MET=4.0 PT=4.0 FTBO CON
EP, 02, 202106011131, 10, DVTS, CI, , 1430N, 10980W, , 2, 55, 2,

.PATEL run with SAB.

[Subtrop]

TXPZ29 KNES 011202
TCSENP
A. 02E (BLANCA)
B. 01/1130Z
C. 13.8N
D. 108.7W
E. ONE/GOES-W
F. T4.5/4.5
G. IR/EIR
H. REMARKS...SYSTEM DISPLAYS AN EYE LIKE FEATURE WITH MG FOR EYE TEMP
AND BLACK AS THE SURROUNDING RING TEMP EMBEDDED IN LG RESULTING IN A DT
OF 5.0 FOR EYE PATTERN. MET AND PT ARE 4.0. FT IS BASED ON CONSTRAINTS
OF FT CANNOT BE GREATER THAN 1 OVER 6 HOURS FROM PREVIOUS FT.
I. ADDL POSITIONS
NIL

...PATEL

......

TXPZ29 KNES 011308
TCSENP
CCA

A. 02E (BLANCA)
B. 01/1130Z
C. 14.3N
D. 109.8W
E. THREE/GOES-W
F. T2.5/3.5
G. IR/EIR/SSMIS
H. REMARKS...CORRECTED FOR POSITION AND INTENSITY BASED ON 1122Z SSMIS
DATA THAT SHOWED THE CENTER FARTHER NW. BANDING OF 4/10 RESULTED IN A
DT OF 2.5. MET IS 1.5 AND PT IS 2.0. FT IS BASED ON CONSTRAINTS LIMITING
CHANGES IN T-NO. TO 1.0 OVER 6 HOURS.
I. ADDL POSITIONS
01/1122Z 14.3N 109.8W SSMIS

...PATEL

[cycloneye]

BULLETIN
Tropical Storm Blanca Advisory Number 8
NWS National Hurricane Center Miami FL EP022021
900 AM MDT Tue Jun 01 2021

...BLANCA NO LONGER EXPECTED TO INTENSIFY...


SUMMARY OF 900 AM MDT...1500 UTC...INFORMATION
----------------------------------------------
LOCATION...14.3N 110.2W
ABOUT 315 MI...505 KM S OF SOCORRO ISLAND
ABOUT 595 MI...955 KM S OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...WNW OR 300 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...999 MB...29.50 INCHES


Tropical Storm Blanca Discussion Number 8
NWS National Hurricane Center Miami FL EP022021
900 AM MDT Tue Jun 01 2021

Blanca's satellite appearance has degraded some this morning, with
the convective structure evolving more into a shear pattern. Recent
SSMIS microwave passes and first-light visible imagery suggest the
center is now located on the southwest edge of a recent convective
burst. The latest subjective Dvorak classifications are lower than
last night with T2.5/35 kt from SAB and T3.0/45 kt from TAFB. The
initial intensity was kept at 50 kt for this advisory, but that
could be generous.

The cyclone's estimated motion is 300/6 kt, a bit more westward than
before. The track philosophy has not changed much this advisory, as
a mid- to upper-level trough near the Baja California peninsula is
beginning to weaken the steering ridge. Thus, Blanca is expected to
move generally west-northwestward with a continued decrease in
forward speed over the next couple of days. Afterwards, the system
should turn more westward within the low-level trade winds as it
becomes vertically shallow. The latest NHC forecast track is a bit
further southward than the previous advisory, but remains close to
the HCCA corrected consensus aid.

First-light visible imagery suggests that the low-level center of
Blanca may be in the process of becoming exposed. Owing to the
degradation in the current satellite structure, Blanca is no longer
expected to intensify, and in fact may already be weaker than
currently estimated. Increasing vertical wind shear appears to be
disrupting the current structure of the cyclone. A gradual weakening
trend is now forecast to begin by this evening through the end of
the forecast period as Blanca moves into an environment of drier
mid-level air and cooler sea surface temperatures. The NHC intensity
forecast remains close to the HCCA and ICON consensus aids.


FORECAST POSITIONS AND MAX WINDS

INIT 01/1500Z 14.3N 110.2W 50 KT 60 MPH
12H 02/0000Z 14.8N 110.8W 45 KT 50 MPH
24H 02/1200Z 15.2N 111.7W 45 KT 50 MPH
36H 03/0000Z 15.5N 112.3W 40 KT 45 MPH
48H 03/1200Z 15.6N 112.9W 35 KT 40 MPH
60H 04/0000Z 15.7N 113.7W 30 KT 35 MPH
72H 04/1200Z 15.8N 114.6W 30 KT 35 MPH
96H 05/1200Z 16.1N 116.7W 25 KT 30 MPH
120H 06/1200Z 16.5N 118.4W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Papin/Stewart

[JW-_-]

looked like a small feature also on that vapor loop. In roughly the same position. Dvorak not so good with micro features.

[Sciencerocks]

[DorkyMcDorkface]

Looks like this may be it for Blanca. Certainly fooled me with the curling CBs and low-level cyan ring it displayed on MW last night, but it's definitely getting sheared now. Combine that with the stable airmass it's moving into (evident with the stratocumulus to its NW) and it's only downhill from here.

[ElectricStorm]

Looking pretty decent right now. I could see this try to make a run towards a brief minimal hurricane before it hits the unfavorable environment.

Never mind. It's a slop fest now

[Sciencerocks]

[cycloneye]

EP, 02, 2021060118, , BEST, 0, 147N, 1107W, 45, 1001, TS, 34, NEQ, 40, 30, 0, 30, 1010, 120, 20, 0, 0, E, 0, , 0, 0, BLANCA, M

[Yellow Evan]

Still generous.

[cycloneye]

Tropical Storm Blanca Discussion Number 9
NWS National Hurricane Center Miami FL EP022021
300 PM MDT Tue Jun 01 2021

Over the last 12 h, Blanca's convective structure has continued to
degrade. The low-level circulation center is now fully exposed to
the west of a small region of deep convection, though
disorganized convective towers are currently trying to redevelop
closer to the center. Even though deep-layer southwesterly
200-850-mb vertical wind shear diagnosed by GFS-SHIPS is still only
15-20 kt, stronger 25-30 kt mid-level shear appears to be
undercutting Blanca's outflow layer. This shear may have resulted in
Blanca ingesting dry, stable mid-level air from the west that has
significantly disrupted the cyclone's convective structure today.
Unfortunately all three scatterometer passes missed Blanca's center
and maximum winds this afternoon. However, given the marked decrease
in organization of Blanca's structure, plus recent subjective
satellite estimates from SAB and TAFB at T3.0/45 kt, the initial
intensity has been lowered to 45 kt for this advisory.

Blanca's exposed center has made it easier to determine its current
position and motion, which over the past 12 h is estimated at 300/8
kt, though the shorter-term motion has been more westward. As
previously discussed, the mid-level ridge that had been steering
Blanca to the west-northwest has been gradually weakening as a
pronounced mid- to upper-level trough centered over the Baja
California peninsula digs in. The end result is Blanca's forward
motion toward the west-northwest is likely to slow further.
Additional asymmetric convective bursts primarily occuring east of
the low-level center may also act to slow down Blanca's forward
motion. As the storm becomes more vertically shallow, it will
increasingly be influenced by the low-level steering flow resulting
in a gradual westward bend in the forecast track until Blanca
dissipates. The latest NHC forecast track has shifted a bit more
south and west this cycle, owing to the possibility that Blanca may
become a shallow vortex sooner than expected, but still agrees
closely with the HCCA corrected consensus with a little more weight
placed on the leftward bending guidance.

The same mid- to upper-level trough slowing the steering currents
have also resulted in a significant increase in mid-level shear over
Blanca, halting any further intensification. Over the next 12-24 h,
intermittent diurnal convective bursts as the cyclone remains over
28-29 C sea surface temperatures should lead to only gradual
weakening. However, even drier mid-level air and lower sea-surface
temperatures exist along Blanca's forecast track and the cyclone is
forecast to weaken to a tropical depression by 60 h and degenerate
to a remnant low by 96 h, though this could occur sooner if
organized convection dissipates faster than forecast.


FORECAST POSITIONS AND MAX WINDS

INIT 01/2100Z 14.7N 110.9W 45 KT 50 MPH
12H 02/0600Z 15.0N 111.6W 40 KT 45 MPH
24H 02/1800Z 15.4N 112.3W 40 KT 45 MPH
36H 03/0600Z 15.6N 112.9W 35 KT 40 MPH
48H 03/1800Z 15.7N 113.5W 35 KT 40 MPH
60H 04/0600Z 15.7N 114.4W 30 KT 35 MPH
72H 04/1800Z 15.8N 115.5W 30 KT 35 MPH
96H 05/1800Z 15.9N 117.6W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 06/1800Z 15.9N 119.2W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Papin/Stewart

[Sciencerocks]

[aspen]

https://imagizer.imageshack.com/img923/9750/Lndshy.gif

Not done yet, it seems.

Stable air really put a lid on this when it had an otherwise favorable environment to intensify. I wonder if this could be a common problem this year in the EPac since a +ENSO is unlikely.

[Yellow Evan]

Looks a little better though clearly sheared. Textbook sheared tropical storm look with convection displaced but not exposed.

[Yellow Evan]

TXPZ29 KNES 020027
TCSENP

A. 02E (BLANCA)

B. 01/2330Z

C. 14.8N

D. 111.2W

E. THREE/GOES-W

F. T2.5/2.5

G. IR/EIR/VIS/AMSR2

H. REMARKS...A LLCC WITH TIGHTLY DEFINED CLOUD LINES THAT LIES BENEATH
THE ANVIL OF A SMALL AREA OF ACTIVE CONVECTION RESULTS IN A DT OF 2.0. THE
MET IS 3.0 BASED ON A SLOW WEAKENING TREND IN APPARENT INTENSITY OVER
THE PAST 24 HOURS. THE PT IS 2.5. THE FT IS BASED ON THE PT DUE TO
UNCERTAINTY IN THE EXACT EXTENT OF WHAT IS CURRENTLY ACTIVE CONVECTION
VERSUS ANVIL DEBRIS.

I. ADDL POSITIONS

01/2030Z 14.7N 110.9W AMSR2


...HOSLEY

[cycloneye]

EP, 02, 2021060200, , BEST, 0, 148N, 1114W, 45, 1001, TS, 34, NEQ, 40, 30, 0, 30, 1010, 180, 20, 0, 0, E, 0, , 0, 0, BLANCA, M

[cycloneye]

Tropical Storm Blanca Discussion Number 10
NWS National Hurricane Center Miami FL EP022021
900 PM MDT Tue Jun 01 2021

A cirrus canopy associated with a resurgence of deep convection
is obscuring Blanca's center. However, the cirrus has a
sharp western edge in infrared satellite imagery, indicative of
continued southwesterly shear. Because Blanca's satellite
appearance is a little better than it was earlier today, the
initial intensity is being held at 45 kt, in best agreement with
a Dvorak classification of T3.0 from TAFB.

A 2030 UTC AMSR microwave pass and recent visible images suggest
that Blanca has turned slightly to the left and slowed down, with
the initial motion now estimated to be 295/6 kt. This slower
motion is the result of a mid- to upper-level low which has
developed near the northern Baja California peninsula and has
dissolved the subtropical ridge. With the steering flow
essentially collapsing, Blanca is forecast to drift westward in the
coming days, with its slowest forward speeds occurring from 24-48
hours. After 48 hours, there should be enough of a low-level ridge
to help a weakening Blanca move a little faster toward the west
within the trade wind flow. Overall, the NHC track forecast favors
a solution on the southern side of the guidance envelope, close to
the previous forecast and the HFIP Corrected Consensus (HCCA).

Several environmental factors are likely to contribute to Blanca's
weakening over the next few days. (1) Moderate southwesterly
vertical shear, caused by the aforementioned mid-/upper-level
trough, is expected to gradually increase over the next 2 to 3
days, (2) the upper-level environment is forecast to become more
subsident after 24 hours, and (3) Blanca will be heading toward
marginally warm waters of around 26 degrees Celsius. Gradual
weakening is therefore expected, and Blanca could become a tropical
depression within 48 hours and a remnant low by day 4. The
intensity models are in good agreement on a gradual weakening
trend, and the NHC official forecast closely follows the IVCN
intensity consensus and the HCCA model.


FORECAST POSITIONS AND MAX WINDS

INIT 02/0300Z 14.9N 111.6W 45 KT 50 MPH
12H 02/1200Z 15.1N 112.2W 40 KT 45 MPH
24H 03/0000Z 15.3N 112.8W 40 KT 45 MPH
36H 03/1200Z 15.5N 113.4W 35 KT 40 MPH
48H 04/0000Z 15.6N 114.1W 30 KT 35 MPH
60H 04/1200Z 15.6N 115.2W 30 KT 35 MPH
72H 05/0000Z 15.6N 116.3W 25 KT 30 MPH
96H 06/0000Z 15.7N 118.4W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 07/0000Z 16.0N 120.0W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Berg

[cycloneye]

Tropical Storm Blanca Discussion Number 11
NWS National Hurricane Center Miami FL EP022021
300 AM MDT Wed Jun 02 2021

Recent satellite imagery indicates southwesterly vertical wind shear
continues to impinge on the western side of Blanca's circulation.
The coldest cloud tops are displaced to the east of the estimated
center, and deep convection is becoming more limited in coverage.
GMI microwave data from 0450 UTC suggest the cyclone's low-level
circulation is losing some definition and may contain multiple
centers. Unfortunately, none of the overnight scatterometer passes
sampled the core of Blanca, although a recent ASCAT-A pass shows
several 30-32 kt wind vectors in the eastern semicircle over 60 n mi
from the center. The initial intensity is decreased to 40 kt with
this advisory, which falls between the subjective Dvorak estimates
from SAB (35 kt) and TAFB (45 kt) and is consistent with the latest
UW-CIMSS ADT current intensity estimate.

Environmental conditions along Blanca's forecast track should
maintain the current weakening trend through the forecast period.
This includes stronger vertical wind shear over the next few days
associated with a mid- to upper-level low near Baja California, in
addition to decreased oceanic heat content and a drier, more stable
environment aloft. The official NHC intensity forecast closely
follows the intensity consensus aid (IVCN), and Blanca is expected
to become a tropical depression by Thursday and a remnant low this
weekend.

The cyclone continues to turn more westward and slow down under
weakening steering currents, and its estimated motion is now an
uncertain 285/5 kt. A general westward motion is expected during the
next several days as the weakening cyclone is largely steered by the
low-level easterly trades. Based on a noticeable southward shift in
much of the guidance including the HFIP corrected consensus (HCCA),
the latest NHC track forecast is adjusted left of track from the
previous one and lies closer to the TVCE consensus aid.


FORECAST POSITIONS AND MAX WINDS

INIT 02/0900Z 15.0N 112.0W 40 KT 45 MPH
12H 02/1800Z 15.1N 112.5W 35 KT 40 MPH
24H 03/0600Z 15.3N 113.3W 35 KT 40 MPH
36H 03/1800Z 15.3N 114.0W 30 KT 35 MPH
48H 04/0600Z 15.3N 115.1W 30 KT 35 MPH
60H 04/1800Z 15.2N 116.2W 25 KT 30 MPH
72H 05/0600Z 15.1N 117.5W 25 KT 30 MPH
96H 06/0600Z 15.5N 119.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 07/0600Z 16.0N 121.0W 20 KT 25 MPH...POST-TROP/REMNT LOW

$$
Forecaster Reinhart/Beven