EPAC: RACHEL - Post-Tropical

[Yellow Evan]

There is no big interest in this storm as it was with Marie and Odile.

Somewhat surprising IMO, given there is nothing else to track (Aside from Kammuari).

[cycloneye]

There is no big interest in this storm as it was with Marie and Odile.

Somewhat surprising IMO, given there is nothing else to track (Aside from Kammuari).

Another factor is many people have lost interest in the tropics as the Atlantic has been well below normal all season.

[wxmann_91]

There is no big interest in this storm as it was with Marie and Odile.

Somewhat surprising IMO, given there is nothing else to track (Aside from Kammuari).

Not surprising at all. There's no shot of Rachel becoming anything more than a high-end TS or low-end hurricane.

[RL3AO]

I've been too focused on getting a blue name to post much.

[Cyclenall]

Another factor is many people have lost interest in the tropics as the Atlantic has been well below normal all season.

Around this time of September is a slow/low activity period on S2K especially if there isn't anything in the Atlantic like during the past 5 years or so from Sept 23-30. Because the Atlantic hurricane season has been boring again this year, its worse than ever and will continue to get worse if something big doesn't change. I just don't care at all about the tropics as of the last week. The last few years for the Atlantic only.

I've been too focused on getting a blue name to post much.

And I'll be doing the same if this keeps up over multiple years. There are certain multi-year cycles that are very ideal for becoming a met because studying to become one eliminates spare-time for tracking and following weather at the enthusiast level, and if the weather cycle is extremely terrible/dull/boring...its a perfect time to focus on becoming a met. On the flip side, if its a 2010-2012 type global pattern or NA one its a very bad time to have limited attention to the chaos being unleashed. Based on my opinion of what makes interesting weather, August 2012 would have been the perfect time to start all the way up to now. By the time you become a met, the cycle will likely be switched again if timed according to what you like in weather (hot or cold/drought or flood based extreme weather).

[wxman57]

Rachel looks highly-sheared with an exposed center. May weaken to a TD tomorrow if the shear doesn't let up.

[TheStormExpert]

It seems since Odile that wind shear has become more problematic. Why is that?

[Yellow Evan]

It seems since Odile that wind shear has become more problematic. Why is that?

A suppressed phase of the Kelvin Wave likely is partially to blame.

[Yellow Evan]

20140926 0000 17.3 111.4 T2.0/3.0 18E RACHEL

[Yellow Evan]

EP, 18, 2014092600, , BEST, 0, 174N, 1114W, 40, 1001, TS, 34, NEQ, 50, 30, 30, 50, 1007, 200, 30, 0, 0, E, 0, , 0, 0, RACHEL, M,

[galaxy401]

It seems since Odile that wind shear has become more problematic. Why is that?

The EPAC season peaks earlier than the Atlantic so it's not a surprise to see activity declining.

[cycloneye]

BULLETIN
TROPICAL STORM RACHEL ADVISORY NUMBER 7
NWS NATIONAL HURRICANE CENTER MIAMI FL EP182014
800 PM PDT THU SEP 25 2014

...RACHEL REMAINS A TROPICAL STORM MOVING WEST-NORTHWESTWARD OVER
THE OPEN PACIFIC...


SUMMARY OF 800 PM PDT...0300 UTC...INFORMATION
----------------------------------------------
LOCATION...17.7N 111.9W
ABOUT 380 MI...615 KM SSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...WNW OR 300 DEGREES AT 15 MPH...24 KM/H
MINIMUM CENTRAL PRESSURE...1001 MB...29.56 INCHES


TROPICAL STORM RACHEL DISCUSSION NUMBER 7
NWS NATIONAL HURRICANE CENTER MIAMI FL EP182014
800 PM PDT THU SEP 25 2014

While there is strong, deep convection associated with Rachel,
microwave and last light visible imagery indicate that the tropical
storm is still being sheared with the center at the edge of the
convective overcast. Subjective Dvorak assessments from TAFB and
SAB as well as the CIMSS AMSU method suggest peak sustained winds of
about 45 kt, which is the initial intensity. While an upper-level
anticyclone is contributing toward about 15 kt of northeasterly
shear over Rachel currently, this should subside to quite low values
from 24 through 72 hr. However, at the same time, Rachel's track
should take it over gradually cooler waters and into much drier,
stable air. The NHC intensity forecast calls for slow
intensification through two days, followed by gradual weakening.
This prediction is based upon a blend of the LGEM and SHIPS
statistical and GFDL dynamical models and is about the same as in
the previous advisory.

No in situ observations were available for the tropical-storm-force
wind radii, so no changes were made to the initial small size of
Rachel. The global and regional hurricane models suggest that
Rachel will remain relatively small for the next few days, which is
the basis for the NHC wind radii forecast.

Rachel is moving toward the west-northwest at 13 kt, primarily being
steered by a mid-level subtropical ridge to its northeast. The
tropical storm should round the western periphery of the ridge in
about two to three days. After that time, Rachel will meander as a
decaying vortex in the weak lower tropospheric flow. The NHC track
forecast is based upon the tightly clustered TVCE multi-model
ensemble and is about the same as that issued in the previous
advisory.


FORECAST POSITIONS AND MAX WINDS

INIT 26/0300Z 17.7N 111.9W 45 KT 50 MPH
12H 26/1200Z 18.4N 113.4W 50 KT 60 MPH
24H 27/0000Z 19.2N 114.7W 55 KT 65 MPH
36H 27/1200Z 20.2N 115.6W 60 KT 70 MPH
48H 28/0000Z 20.9N 116.2W 60 KT 70 MPH
72H 29/0000Z 22.2N 116.3W 50 KT 60 MPH
96H 30/0000Z 23.0N 116.0W 40 KT 45 MPH
120H 01/0000Z 23.0N 116.0W 25 KT 30 MPH

$$
Forecaster Landsea

[Yellow Evan]

Looking okay tonight. Very cold cloud tops.

[HurricaneRyan]

These Rachel storms never seem to get their acts together. Just once I'd like to see one be as fierce as Rachel Green!

[cycloneye]

TROPICAL STORM RACHEL DISCUSSION NUMBER 8
NWS NATIONAL HURRICANE CENTER MIAMI FL EP182014
200 AM PDT FRI SEP 26 2014

Microwave data indicate that Rachel's structure has changed
little during the past few hours, and the maximum winds are
therefore held at 45 kt. Deep convection remains limited to the
southwest of the low-level center, although a recent expansion of
the cold cloud tops in infrared satellite imagery suggests that the
northeasterly shear may be relaxing just a bit. The SHIPS guidance
indicates that the shear should gradually diminish, reaching a
minimum in about 36 hours, so gradual strengthening is anticipated
up through that time. After 36 hours, the shear is expected to
increase while Rachel moves over marginally cooler water and into a
drier, more stable environment. Steady weakening is expected to
begin by 48 hours, with the cyclone likely becoming a remnant low
by day 5. The updated NHC intensity forecast is not too dissimilar
from the previous one. However, it should be noted that the
60-kt forecast peak intensity is a little higher than all of the
guidance except the HWRF.

Rachel's initial motion is 300/12 kt. The track models are in good
agreement during the first 36-48 hours, showing Rachel slowing down
and turning north-northwestward toward a break in the subtropical
ridge. There is significant divergence in the guidance after 48
hours, however. The notable outliers are the GFS and the GFDL
ensemble mean, which have a stronger cyclone being pulled
northeastward toward the Baja California peninsula by a deep-layer
trough over the southwestern United States. The other models show
a weaker cyclone stalling and then turning southward or
southwestward within the prevailing low-level flow. Due to the
model divergence, very slow motion is indicated between days 3-5,
and Rachel is expected to become nearly stationary before drifting
southwestward during its remnant low stage. The guidance shifted a
bit to the west on this cycle, and although the NHC forecast was
also nudged in that direction, it still lies on the eastern edge of
the envelope.

FORECAST POSITIONS AND MAX WINDS

INIT 26/0900Z 18.0N 112.9W 45 KT 50 MPH
12H 26/1800Z 18.7N 114.3W 50 KT 60 MPH
24H 27/0600Z 19.7N 115.4W 55 KT 65 MPH
36H 27/1800Z 20.6N 116.2W 60 KT 70 MPH
48H 28/0600Z 21.4N 116.7W 55 KT 65 MPH
72H 29/0600Z 22.7N 116.8W 45 KT 50 MPH
96H 30/0600Z 23.0N 116.5W 35 KT 40 MPH
120H 01/0600Z 22.5N 117.0W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Berg

[Yellow Evan]

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.2.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 26 SEP 2014 Time : 110000 UTC
Lat : 18:08:41 N Lon : 113:12:33 W


CI# /Pressure/ Vmax
2.6 /1004.3mb/ 37.0kt


Final T# Adj T# Raw T#
2.6 2.8 3.1

Center Temp : -55.9C Cloud Region Temp : -50.3C

Scene Type : IRREGULAR CDO*

Positioning Method : FORECAST INTERPOLATION

Ocean Basin : EAST PACIFIC
Dvorak CI > MSLP Conversion Used : ATLANTIC

Tno/CI Rules : Constraint Limits : 0.7T/6hr
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

C/K/Z MSLP Estimate Inputs :
- Average 34 knot radii : 40km
- Environmental MSLP : 1011mb

Satellite Name : GOES15
Satellite Viewing Angle : 32.7 degrees

[Yellow Evan]

20140926 1200 17.5 113.5 T2.0/2.0 18E RACHEL

Bulletin Archive

TXPZ26 KNES 261227
TCSENP

A. 18E (RACHEL)

B. 26/1200Z

C. 17.5N

D. 113.5W

E. THREE/GOES-W

F. T2.0/2.0/W1.0/24HRS

G. IR/EIR/SWIR/TMI

H. REMARKS...DT OF 2.0 IS BASED ON A SHEAR PATTERN CHARACTERIZED BY
TIGHLY DEFINED LL CIRCULAR CLOUD LINES, AND THE CENTER NEAR TO A SMALL
AREA (LT 90NM) OF ACTIVE CONVECTION. MET AND PT ARE 2.5. FT IS BASED
ON DT.

I. ADDL POSITIONS

26/0608Z 17.5N 112.6W TMI

45 knts is quite generous.

[Yellow Evan]

EP, 18, 2014092612, , BEST, 0, 183N, 1137W, 45, 1001, TS, 34, NEQ, 50, 30, 30, 50, 1009, 180, 30, 0, 0, E, 0, , 0, 0, RACHEL, M,

I would never have given this 45 knts.

[cycloneye]

BULLETIN
TROPICAL STORM RACHEL ADVISORY NUMBER 9
NWS NATIONAL HURRICANE CENTER MIAMI FL EP182014
800 AM PDT FRI SEP 26 2014

...CENTER OF RACHEL NEAR CLARION ISLAND...


SUMMARY OF 800 AM PDT...1500 UTC...INFORMATION
----------------------------------------------
LOCATION...18.2N 114.4W
ABOUT 435 MI...700 KM SW OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...WNW OR 295 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...1001 MB...29.56 INCHES


WATCHES AND WARNINGS
--------------------
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 800 AM PDT...1500 UTC...THE CENTER OF TROPICAL STORM RACHEL WAS
LOCATED NEAR LATITUDE 18.2 NORTH...LONGITUDE 114.4 WEST. RACHEL IS
MOVING TOWARD THE WEST-NORTHWEST NEAR 14 MPH...22 KM/H. A TURN
TOWARD THE NORTHWEST AND NORTH-NORTHWEST WITH A SIGNIFICANT DECREASE
IN FORWARD SPEED IS EXPECTED DURING THE NEXT COUPLE OF DAYS.

MAXIMUM SUSTAINED WINDS REMAIN NEAR 50 MPH...85 KM/H...WITH HIGHER
GUSTS. SOME STRENGTHENING IS FORECAST DURING THE NEXT DAY OR SO...
FOLLOWED BY WEAKENING BY SUNDAY.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 60 MILES...95 KM
FROM THE CENTER.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1001 MB...29.56 INCHES.


HAZARDS AFFECTING LAND
----------------------
NONE


NEXT ADVISORY
-------------
NEXT COMPLETE ADVISORY...200 PM PDT.

$$
FORECASTER KIMBERLAIN



TROPICAL STORM RACHEL DISCUSSION NUMBER 9
NWS NATIONAL HURRICANE CENTER MIAMI FL EP182014
800 AM PDT FRI SEP 26 2014

The organization of Rachel's cloud pattern has not changed this
morning. The center of the cyclone remains on the northeast
(upshear) side and outside of a large mass of very cold-topped
convection, presumably a result of some northeasterly vertical wind
shear. The deep convection continues to regularly burst, a trend
that has been observed for a few days now. The initial intensity
estimate is held at 45 kt in agreement with the 1200 UTC Dvorak fix
from TAFB. Global models show Rachel moving underneath an upper-
level ridge axis during the next 24 hours or so, which should result
in a relaxation of the persistent shear and allow for some
intensification since the storm will still be over warm enough
waters. In 2-3 days, Rachel will have moved far enough to the north
to experience an increase of southwesterly shear in response to a
mid-latitude trough over the western United States. That shear and
increasingly unfavorable thermodynamics factors, including somewhat
cooler waters, are expected to hasten its weakening beyond 48 hours.
The NHC intensity forecast is not much different than the previous
one, and still shows remnant low status at the end of the forecast
period.

Rachel continues on a west-northwesterly track of 295/12. The
cyclone is forecast to turn toward the northwest and north-
northwest with a significant decrease in forward speed during the
next couple of days when it encounters a weakness caused by the
earlier-mentioned western United States trough. By 48 hours, there
is a rather distinct split in the track guidance, with the GFS-based
model solutions carrying the cyclone quickly northward and
northeastward while the ECMWF/UKMET suggest a weaker cyclone
steered toward the west-northwest and west. The NHC track forecast
stays left of but closer to the GFS through 48 hours due to Rachel's
forecast intensification and then shows slow motion for the
remainder of the forecast period. The 48-120 hour portion of the
track forecast is very near the multi-model consensus, TVCE, and it
could trend westward in future forecasts if confidence in a weaker
cyclone at that time frame increases.



FORECAST POSITIONS AND MAX WINDS

INIT 26/1500Z 18.2N 114.4W 45 KT 50 MPH
12H 27/0000Z 19.0N 115.2W 50 KT 60 MPH
24H 27/1200Z 20.0N 116.1W 55 KT 65 MPH
36H 28/0000Z 20.9N 116.8W 60 KT 70 MPH
48H 28/1200Z 21.8N 117.1W 50 KT 60 MPH
72H 29/1200Z 22.8N 117.2W 40 KT 45 MPH
96H 30/1200Z 23.0N 117.2W 30 KT 35 MPH
120H 01/1200Z 22.8N 117.4W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Kimberlain

[cycloneye]

BULLETIN
TROPICAL STORM RACHEL ADVISORY NUMBER 10
NWS NATIONAL HURRICANE CENTER MIAMI FL EP182014
200 PM PDT FRI SEP 26 2014

...RACHEL MOVING WEST-NORTHWESTWARD WITH NO CHANGE IN STRENGTH...


SUMMARY OF 200 PM PDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...18.1N 115.0W
ABOUT 465 MI...750 KM SW OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...1001 MB...29.56 INCHES



TROPICAL STORM RACHEL DISCUSSION NUMBER 10
NWS NATIONAL HURRICANE CENTER MIAMI FL EP182014
200 PM PDT FRI SEP 26 2014

The center of Rachel appears to be reforming a little closer to the
deep convection, and in fact looks somewhat elongated on the latest
visible imagery. The SHIPS model and UW-CIMSS satellite analyses
still show about 10 kt of shear affecting the cyclone, and overall
there has been little net change to the cloud pattern today. The
initial intensity remains 45 kt based on the latest Dvorak estimate
from TAFB. The SHIPS model shows the shear decreasing over the next
24 hours, which should allow for some gradual strengthening, but the
SHIPS intensity forecast has trended downward this cycle along with
the GFDL. After 36 hours, gradual weakening is forecast as the
cyclone moves into a drier and more stable environment over
marginal SSTs and decay to a remnant low is expected in 4 to 5 days.
The NHC forecast has been adjusted downward a little in the short
range toward the latest IVCN intensity consensus and is close to
IVCN after that time.

Given the reformation of the center, the initial position is
southwest of the previous advisory. Smoothing through this short-
term motion yields a somewhat uncertain initial motion estimate of
295/10. The synoptic reasoning for the track forecast has not
changed. Rachel is forecast to turn gradually northward into a
break in the subtropical ridge with a decrease in forward speed
during the next couple of days. After that time, the decaying
cyclone is forecast to move little in a region of weak steering
currents, with a slow southwestward motion possible by the end
of the period. There continues to be a large spread in the track
guidance after 36 hours, with the GFS and GFDL taking the cyclone
farther north while the UKMET and ECMWF show a more westward to
southwestward motion. The new NHC forecast track is generally
between the two camps and is a little left of the TVCE multi-model
consensus and not far from the HWRF. This track is west of the
previous NHC advisory due to the initial position and motion.

FORECAST POSITIONS AND MAX WINDS

INIT 26/2100Z 18.1N 115.0W 45 KT 50 MPH
12H 27/0600Z 18.7N 115.9W 50 KT 60 MPH
24H 27/1800Z 19.7N 116.6W 55 KT 65 MPH
36H 28/0600Z 20.6N 117.1W 55 KT 65 MPH
48H 28/1800Z 21.3N 117.3W 50 KT 60 MPH
72H 29/1800Z 22.0N 117.3W 40 KT 45 MPH
96H 30/1800Z 22.0N 117.3W 30 KT 35 MPH
120H 01/1800Z 21.5N 117.5W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Brennan