EPAC: OTIS - Post-Tropical

[Extratropical94]

These are the remnants of Katia apparently.

95E INVEST 170911 0600 16.3N 109.2W EPAC 20 1009

The remnants of Katia located about 300 miles west-southwest of
Manzanillo, Mexico continue to produce an area of showers and
thunderstorms. Strong upper-level winds should limit development of
this system while it moves westward at 10 to 15 mph during the next
couple of days.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...low...20 percent.

[Extratropical94]

The remnants of Katia located about 350 miles west-southwest of
Manzanillo, Mexico are associated with a low pressure center with
numerous showers and thunderstorms. Strong upper-level winds should
limit development of this system while it moves westward at 10 to 15
mph during the next couple of days.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 5 days...low...30 percent.

[BYG Jacob]

I'm not seeing any kind of strong shear that should effect this, if anything the shear looks like its moving in the same direction as the outflow. SSTs are of course warm around it, and there doesn't look like there's any real dry air in the area, this has a pretty good chance of developing.

[Extratropical94]

11 AM:

The remnants of Katia, located about 500 miles west-southwest of
Manzanillo, Mexico, are associated with a well-defined low pressure
center. Showers and thunderstorms with this system have become
better organized during the last day or so. Despite upper-level
winds appearing to be hostile for development over the next few
days, any additional improvement in the convective organization
could lead to the formation of a tropical cyclone while the system
moves westward at 10 to 15 mph.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 5 days...medium...50 percent.

[BYG Jacob]

11 AM:

The remnants of Katia, located about 500 miles west-southwest of
Manzanillo, Mexico, are associated with a well-defined low pressure
center. Showers and thunderstorms with this system have become
better organized during the last day or so. Despite upper-level
winds appearing to be hostile for development over the next few
days, any additional improvement in the convective organization
could lead to the formation of a tropical cyclone while the system
moves westward at 10 to 15 mph.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 5 days...medium...50 percent.

Environment around it is very favorable, wouldn't be shocked to see a major.

[galaxy401]

So will this storm get named Katia again or Max? I would assume Max since it's reforming in the Pacific but the outlooks stated that this is "the remnants of Katia" and not "associated with the remnants of Katia" so it seems more directly related.

[Extratropical94]

So will this storm get named Katia again or Max? I would assume Max since it's reforming in the Pacific but the outlooks stated that this is "the remnants of Katia" and not "associated with the remnants of Katia" so it seems more directly related.

The whole 'remnants regenerating and keeping their name'-thing only applies when a system does not cross over into another basin. In this case Katia dissipated as a TC and crossed over, so 95E will be named Max (or Norma, should the other area develop into a TS first).

Here's an overview regarding names:

TC dissipates and its remnants REGENERATE IN THE SAME BASIN SAME name, SAME number (Example: 09L.HARVEY 09L.HARVEY)
TC dissipates and its remnants REGENERATE IN A DIFFERENT BASIN DIFFERENT name, DIFFERENT number (Example: 13L.KATIA 15E.MAX (or maybe 16E.NORMA))
TC CROSSES INTO ANOTHER BASIN and doesn't dissipate while doing so SAME name, DIFFERENT number (Example: 2016 16L.OTTO 22E.OTTO)
TC dissipates and something develops that is not closely associated to the remnants of the TC DIFFERENT name, DIFFERENT number (Example: 2005 10L.TEN 12L.KATRINA)

[Kingarabian]

Well defined LLC. Only an increase in convection for this system to be classified.



Good amount of shear still hampering it.

[BYG Jacob]

Well defined LLC. Only an increase in convection for this system to be classified.



Good amount of shear still hampering it.

Wow, that's organizing really well in the face of shear.

[EquusStorm]

Convection seems to be pretty persistent over the LLC, now, and I assume if that holds true for the next few hours they would consider starting advisories. I'm quite surprised there was enough left of Katia after being shredded over Mexico to do anything in the EPac; it was quite small and tightly wound, after all.

[Yellow Evan]

* EAST PACIFIC SHIPS INTENSITY FORECAST *
* IR SAT DATA AVAILABLE, OHC AVAILABLE *
* INVEST EP952017 09/11/17 18 UTC *

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 25 26 27 29 31 33 37 37 35 31 27 23 19
V (KT) LAND 25 26 27 29 31 33 37 37 35 31 27 23 19
V (KT) LGEM 25 27 28 28 29 28 28 27 25 23 21 19 17
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

SHEAR (KT) 16 15 15 15 15 13 10 16 15 17 19 21 25
SHEAR ADJ (KT) 3 3 2 0 0 0 -2 -4 -5 -1 0 -2 -9
SHEAR DIR 91 116 120 116 118 147 150 176 213 222 254 256 258
SST (C) 28.8 28.5 28.5 28.4 28.2 27.8 27.6 26.9 26.1 25.5 25.3 25.2 25.2
POT. INT. (KT) 154 152 152 150 148 143 140 133 124 117 115 113 112
200 MB T (C) -52.3 -52.2 -52.6 -52.9 -52.7 -52.4 -52.7 -52.4 -52.5 -52.7 -53.2 -53.1 -53.2
200 MB VXT (C) 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
TH_E DEV (C) 8 7 7 6 5 5 4 3 2 2 2 3 2
700-500 MB RH 67 66 63 62 59 57 53 48 43 41 40 38 36
MODEL VTX (KT) 8 LOST LOST LOST LOST LOST LOST LOST LOST LOST LOST LOST LOST
850 MB ENV VOR 66 66 81 79 72 57 46 43 36 51 39 20 7
200 MB DIV 78 81 70 50 35 34 23 24 8 11 -1 -26 -18
700-850 TADV 0 4 5 5 6 6 5 7 5 5 6 0 2
LAND (KM) 743 795 895 1005 1119 1275 1419 1500 1573 1654 1750 1839 1897
LAT (DEG N) 16.4 16.5 16.5 16.5 16.5 16.7 17.2 18.1 18.8 19.5 19.9 20.2 20.3
LONG(DEG W) 111.7 113.4 115.2 116.8 118.4 121.0 123.3 125.2 126.9 128.5 129.9 131.1 131.8
STM SPEED (KT) 15 17 16 15 14 12 11 9 8 7 6 5 3
HEAT CONTENT 18 18 23 24 19 8 8 3 0 0 0 0 0

FORECAST TRACK FROM TABM INITIAL HEADING/SPEED (DEG/KT):270/ 13 CX,CY: -12/ 0
T-12 MAX WIND: 20 PRESSURE OF STEERING LEVEL (MB): 550 (MEAN=550)
GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 29.1 (MEAN=14.5)
% GOES IR PIXELS WITH T < -20 C 50-200 KM RAD: 29.0 (MEAN=65.0)
PRELIM RI PROB (DV .GE. 55 KT IN 48 HR): 0.7

INDIVIDUAL CONTRIBUTIONS TO INTENSITY CHANGE
6 12 18 24 36 48 60 72 84 96 108 120
----------------------------------------------------------
SAMPLE MEAN CHANGE 0. 0. 1. 1. 1. 1. 1. 1. -0. -1. -1. -2.
SST POTENTIAL -0. -0. 0. 1. 7. 14. 20. 25. 28. 29. 29. 27.
VERTICAL SHEAR MAG 1. 2. 2. 2. 2. 1. -1. -4. -7. -9. -10. -10.
VERTICAL SHEAR ADJ -0. -0. -1. -1. -1. -0. -0. 0. 0. 0. 0. 0.
VERTICAL SHEAR DIR 0. 0. 1. 1. 1. 1. 0. -0. -1. -2. -2. -2.
PERSISTENCE 1. 2. 2. 2. 2. 2. 2. 1. 1. 1. 1. 0.
200/250 MB TEMP. -0. -0. -0. -1. -1. -2. -3. -4. -4. -4. -4. -4.
THETA_E EXCESS 0. 0. 0. 0. -0. -1. -2. -3. -4. -6. -7. -8.
700-500 MB RH 0. 0. 0. 0. -0. -0. -0. -1. -2. -2. -3. -4.
MODEL VTX TENDENCY 0. 0. 0. 0. 0. 0. 0. 0. -0. -0. -0. -0.
850 MB ENV VORTICITY -0. -0. -0. -0. -0. -1. -1. -1. -1. -1. -1. -1.
200 MB DIVERGENCE 0. 1. 1. 1. 1. 1. 0. 0. -0. -1. -1. -1.
850-700 T ADVEC 0. 0. -0. -0. 0. 0. 1. 1. 1. 2. 3. 3.
ZONAL STORM MOTION 0. 1. 1. 2. 2. 2. 3. 2. 2. 1. 1. 1.
STEERING LEVEL PRES -0. -0. -0. -0. -0. -0. -0. -0. -0. -1. -1. -1.
DAYS FROM CLIM. PEAK 0. 0. 0. 0. -0. 0. 0. 1. 1. 1. 1. 1.
GOES PREDICTORS -1. -2. -3. -3. -4. -6. -7. -7. -6. -6. -6. -6.
OCEAN HEAT CONTENT -0. 0. 0. 0. -0. -0. -1. -0. -0. -1. -0. 0.
----------------------------------------------------------
TOTAL CHANGE 1. 2. 4. 6. 8. 12. 12. 10. 6. 2. -2. -6.

CURRENT MAX WIND (KT): 25. LAT, LON: 16.4 111.7

** 2017 E.PACIFIC RI INDEX EP952017 INVEST 09/11/17 18 UTC **
(SHIPS-RII PREDICTOR TABLE for 30 KT OR MORE MAXIMUM WIND INCREASE IN NEXT 24-h)

Predictor Value RI Predictor Range Scaled Value(0-1) % Contribution
12 HR PERSISTENCE (KT): 5.0 -22.0 to 44.0 0.41 1.8
POT = MPI-VMAX (KT) : 126.3 40.5 to 149.3 0.79 2.1
850-200 MB SHEAR (KT) : 15.2 18.9 to 1.4 0.21 0.8
HEAT CONTENT (KJ/cm2) : 20.4 0.0 to 106.7 0.19 0.6
MAXIMUM WIND (kt) : 25.0 22.5 to 132.0 0.07 0.2
D200 (10**7s-1) : 62.8 -33.0 to 156.2 0.51 1.3
STD DEV OF IR BR TEMP : 29.1 37.8 to 2.1 0.24 0.7
% AREA WITH TPW <45 mm: 0.0 62.3 to 0.0 1.00 -0.8
2nd PC OF IR BR TEMP : 2.0 2.2 to -1.9 0.05 0.0
BL DRY-AIR FLUX (w/m2): 120.8 735.9 to -82.5 0.75 0.0

SHIPS Prob RI for 20kt/ 12hr RI threshold= 0% is 0.0 times sample mean ( 7.7%)
SHIPS Prob RI for 25kt/ 24hr RI threshold= 8% is 0.5 times sample mean (15.3%)
SHIPS Prob RI for 30kt/ 24hr RI threshold= 7% is 0.6 times sample mean (10.4%)
SHIPS Prob RI for 35kt/ 24hr RI threshold= 0% is 0.0 times sample mean ( 7.5%)
SHIPS Prob RI for 40kt/ 24hr RI threshold= 0% is 0.0 times sample mean ( 5.2%)
SHIPS Prob RI for 45kt/ 36hr RI threshold= 9% is 1.2 times sample mean ( 8.1%)
SHIPS Prob RI for 55kt/ 48hr RI threshold= 0% is 0.0 times sample mean ( 7.4%)
SHIPS Prob RI for 65kt/ 72hr RI threshold= 0% is 0.0 times sample mean ( 5.5%)

Matrix of RI probabilities
------------------------------------------------------------------------------
RI (kt / h) | 20/12 | 25/24 | 30/24 | 35/24 | 40/24 | 45/36 | 55/48 |65/72
------------------------------------------------------------------------------
SHIPS-RII: 0.0% 8.3% 6.7% 0.0% 0.0% 9.4% 0.0% 0.0%
Logistic: 0.9% 7.6% 3.1% 1.0% 0.4% 3.4% 1.0% 0.1%
Bayesian: 0.0% 0.6% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%
Consensus: 0.3% 5.5% 3.3% 0.3% 0.1% 4.3% 0.3% 0.0%

## ANNULAR HURRICANE INDEX (AHI) EP952017 INVEST 09/11/17 18 UTC ##
## STORM NOT ANNULAR, SCREENING STEP FAILED, NPASS=4 NFAIL=3 ##
## AHI= 0 (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##

[Kingarabian]

* EAST PACIFIC SHIPS INTENSITY FORECAST *

That's pretty low from SHIPS if this is the system that's due to affect Baja and potentially the SW states.

[BYG Jacob]

Convection seems to be pretty persistent over the LLC, now, and I assume if that holds true for the next few hours they would consider starting advisories. I'm quite surprised there was enough left of Katia after being shredded over Mexico to do anything in the EPac; it was quite small and tightly wound, after all.

Its kind of shocking how well its organized in the face of shear.

[Yellow Evan]

* EAST PACIFIC SHIPS INTENSITY FORECAST *

That's pretty low from SHIPS if this is the system that's due to affect Baja and potentially the SW states.

I think that's the system behind it.

[Extratropical94]

* EAST PACIFIC SHIPS INTENSITY FORECAST *

That's pretty low from SHIPS if this is the system that's due to affect Baja and potentially the SW states.

I think that's the system behind it.

The 12Z Euro keeps 95E weak on a westward movement and develops the 40/70 area into a strong system slamming into the Baja.
The 12Z GFS loses 95E quickly, slams the 40/70 area into mainland Mexico and develops a new system south of 95's current position which should be what the NHC has at 10/60 right now. It then has that 10/60 area moving up the west coast of the Baja, eventually turning right into the peninsula.

12Z EURO:


12Z GFS:

[Extratropical94]

EP, 15, 2017091118, , BEST, 0, 164N, 1117W, 25, 1006, DB, 34, NEQ, 0, 0, 0, 0, 1009, 120, 30, 0, 0, E, 0, , 0, 0, FIFTEEN, S, 0, , 0, 0, 0, 0, genesis-num, 026, TRANSITIONED, epC52017 to ep152017,

This has been renumbered to FIFTEEN, so advisories might be initiated at 2 pm.

[Kingarabian]

EP, 15, 2017091118, , BEST, 0, 164N, 1117W, 25, 1006, DB, 34, NEQ, 0, 0, 0, 0, 1009, 120, 30, 0, 0, E, 0, , 0, 0, FIFTEEN, S, 0, , 0, 0, 0, 0, genesis-num, 026, TRANSITIONED, epC52017 to ep152017,

This has been renumbered to FIFTEEN, so advisories might be initiated at 2 pm.

Pretty confident advisories will start then. Looks like it will become Max. Possible rain/flooding event for western Mexico.

[Extratropical94]

Tropical Depression Fifteen-E Advisory Number 1
NWS National Hurricane Center Miami FL EP152017
300 PM MDT Mon Sep 11 2017

...A NEW TROPICAL DEPRESSION FORMS SEVERAL HUNDRED MILES WEST OF
MEXICO...


SUMMARY OF 300 PM MDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...16.4N 112.3W
ABOUT 555 MI...895 KM WSW OF MANZANILLO MEXICO
MAXIMUM SUSTAINED WINDS...30 MPH...45 KM/H
PRESENT MOVEMENT...W OR 270 DEGREES AT 15 MPH...24 KM/H
MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
At 300 PM MDT (2100 UTC), the center of Tropical Depression
Fifteen-E was located near latitude 16.4 North, longitude 112.3
West. The depression is moving toward the west near 15 mph (24 km/h)
and is expected to move toward the west or west-southwest at a
slower rate of forward speed during the next two days.

Maximum sustained winds are near 30 mph (45 km/h) with higher gusts.
The system is expected intensify slightly and become a tropical
storm by Wednesday.

The estimated minimum central pressure is 1006 mb (29.71 inches).


HAZARDS AFFECTING LAND
----------------------
None


Tropical Depression Fifteen-E Discussion Number 1
NWS National Hurricane Center Miami FL EP152017
300 PM MDT Mon Sep 11 2017

The remnants of Atlantic Hurricane Katia have redeveloped after
reaching the Pacific Ocean a couple of days ago. The system
maintained a mid-level circulation while transiting the high terrain
of Mexico, but had lost its surface center. Yesterday, deep
convection began in association with the mid-level circulation and
today a well-defined surface center formed. While it was originally
thought that the convection would be sporadic because of the
moderate vertical shear, the deep convection has instead persisted
close to the system's center during the last several hours. Since
the system now meets the definition of a tropical cyclone,
advisories are initiated as Tropical Depression Fifteen.

The depression is moving toward the west at 13 kt, steered
primarily by the deep-layer ridge to its north. The official track
forecast is a westward or west-southwestward motion at a slower
rate of forward speed during the next two days, then a turn back
toward the west or west-northwest at days 3 and 4. This forecast
is based upon a blend of the GFS and ECMWF global models, as the
remaining guidance either doesn't know about the depression or
unrealistically intensifies it and takes it toward the north.

The system likely will not become very substantial. The moderate
shear should continue, while the depression heads toward cool SSTs
and dry air. The official intensity forecast shows just modest
strengthening to a low-end tropical storm in about a day, before
weakening begins. Deep convection may cease in about three days,
marking the system's transition to a remnant low. The intensity
forecast is based upon the LGEM/DSHIP statistical guidance as the
mesoscale dynamical models spin the depression up to near hurricane
strength, which is not plausible. If the system does reach
tropical storm intensity - by no means assured, then it
would be named "Max", not "Katia".


FORECAST POSITIONS AND MAX WINDS

INIT 11/2100Z 16.4N 112.3W 25 KT 30 MPH
12H 12/0600Z 16.2N 114.1W 30 KT 35 MPH
24H 12/1800Z 15.8N 116.2W 35 KT 40 MPH
36H 13/0600Z 15.4N 118.0W 30 KT 35 MPH
48H 13/1800Z 15.3N 119.6W 25 KT 30 MPH
72H 14/1800Z 15.7N 121.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 15/1800Z 16.0N 123.5W 20 KT 25 MPH...POST-TROP/REMNT LOW
120H 16/1800Z...DISSIPATED

$$
Forecaster Landsea

[CrazyC83]

I know it is unrelated, but I personally believe that they should change the rules so that if the remnants regenerate on the other side (either Atlantic to EPAC or vice versa) it should keep the original name. Make clear that this is tied to Katia.

[Yellow Evan]

Seems to have quickly gone poof. As usual with these kind of unexpected formations.