WPAC: KROVANH - Post-Tropical

[cycloneye]

96W INVEST 150913 1200 12.7N 151.9E WPAC 15 1010

[1900hurricane]

The constant convective burst looks good, but microwave doesn't show any organization near the surface yet. 96W is going to need to keep generating convection for the surface pressure falls needed to develop a surface circulation.

[1900hurricane]

JTWC gave it a low.

ABPW10 PGTW 131600
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND
/SOUTH PACIFIC OCEANS REISSUED/131600Z-140600ZSEP2015//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/131351ZSEP2015//
AMPN/REF A IS A TROPICAL CYCLONE WARNING.//
RMKS/
1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA):
A. TROPICAL CYCLONE SUMMARY:
(1) AT 131200Z, TROPICAL DEPRESSION 19W (NINETEEN) WAS LOCATED
NEAR 15.8N 111.3E, APPROXIMATELY 174 NM EAST OF DA NANG, VIETNAM,
AND HAD TRACKED WESTWARD AT 07 KNOTS OVER THE PAST SIX HOURS.
MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED AT 25 KNOTS GUSTING
TO 35 KNOTS. SEE REF A (WTPN31 PGTW 131500) FOR FURTHER DETAILS.
(2) NO OTHER TROPICAL CYCLONES.
B. TROPICAL DISTURBANCE SUMMARY:
(1) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 15.7N
112.6E, IS NOW THE SUBJECT OF A TROPICAL CYCLONE WARNING. SEE PARA.
1.A.(1) FOR FURTHER DETAILS.
(2) AN AREA OF CONVECTION HAS PERSISTED NEAR 13.3N 152.2E,
APPROXIMATELY 435 NM EAST OF ANDERSEN AFB, GUAM. ANIMATED ENHANCED
INFRARED SATELLITE IMAGERY DEPICTS A SYMMETRIC CONVECTIVE SIGNATURE
OBSCURING AN ELONGATED LOW LEVEL CIRCULATION CENTER THAT IS BEING
ENHANCED BY A 15 TO 20 KNOT SOUTHWESTERLY SURGE FAR TO THE SOUTH. A
130840Z SSMIS 37GHZ MICROWAVE IMAGE SHOWS WEAK LOW LEVEL BANDING
WITH THE BULK OF CONVECTION ALONG THE SOUTHWESTERN PERIPHERY. UPPER
LEVEL ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH LOW VERTICAL
WIND SHEAR AND GOOD DUAL CHANNEL OUTFLOW WITH A POLEWARD BIAS DUE TO
A TUTT CELL LOCATED TO THE NORTH. GLOBAL MODELS INDICATE WEAK
DEVELOPMENT OF THE SYSTEM AS IT TRACKS GENERALLY NORTHWARD.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 10 TO 15 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1004 MB. THE
POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS LOW.
(3) NO OTHER SUSPECT AREAS.
2. SOUTH PACIFIC AREA (WEST COAST OF SOUTH AMERICA TO 135 EAST):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY: NONE.
3. JUSTIFICATION FOR REISSUE: UPGRADED AREA IN PARA 1.B.(1) TO
WARNING STATUS AND ADDED AREA IN PARA 1.B.(2) AS A LOW.//
NNNN

[Extratropical94]

96W INVEST 150913 1800 13.7N 151.7E WPAC 20 1006

[1900hurricane]

That was fast, TCFA now up.

WTPN21 PGTW 131930
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
A 200 NM RADIUS OF 13.7N 151.7E WITHIN THE NEXT 12 TO 24 HOURS.
AVAILABLE DATA DOES NOT JUSTIFY ISSUANCE OF NUMBERED TROPICAL
CYCLONE WARNINGS AT THIS TIME. WINDS IN THE AREA ARE ESTIMATED TO
BE 15 TO 20 KNOTS. METSAT IMAGERY AT 131800Z INDICATES THAT A
CIRCULATION CENTER IS LOCATED NEAR 13.7N 151.7E. THE SYSTEM IS
MOVING NORTHWESTWARD AT 06 KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 13.3N
152.2E IS NOW LOCATED NEAR 13.7N 151.7E, APPROXIMATELY 405 NM EAST
OF ANDERSEN AFB, GUAM. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
DEPICTS A DEEPENING CONVECTIVE SIGNATURE OBSCURING AN ELONGATED LOW
LEVEL CIRCULATION CENTER (LLCC) THAT IS BEING ENHANCED BY STRONG
SOUTHWESTERLY SURGE TO THE SOUTH OF THE DISTURBANCE. A 131637Z SSMI
MICROWAVE PASS SHOWS WEAK SHALLOW BANDING WRAPPING INTO THE LLCC
WITH THE BULK OF CONVECTION ALONG THE WESTERN PERIPHERY. UPPER LEVEL
ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH LOW VERTICAL WIND
SHEAR AND GOOD DUAL CHANNEL OUTFLOW ENHANCED BY A TUTT CELL LOCATED
TO THE NORTH. GLOBAL MODELS INDICATE MINIMAL DEVELOPMENT OF THE
SYSTEM OVER THE NEXT 24 HOURS AS IT TRACKS GENERALLY NORTHWARD.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1006 MB. THE
POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
141930Z.//
NNNN

SSMI pass mentioned above:

[Extratropical94]

TROPICAL DEPRESSION 1004 HPA AT 15N 151E WNW SLOWLY.

[euro6208]

[euro6208]

TXPQ21 KNES 131513
TCSWNP

A. TROPICAL DISTURBANCE (96W)

B. 13/1432Z

C. 13.5N

D. 151.4E

E. FIVE/MTSAT

F. T1.0/1.0/D1.0/24HRS

G. IR/EIR/SWIR

H. REMARKS...DT=1.0 BASED ON .2+ BANDING ON LOG10
SPIRAL. PT=1.0. MET=1.0. FT IS BASED ON DT.

I. ADDL POSITIONS

NIL


...SCHWARTZ

TPPN11 PGTW 131834

A. TROPICAL DISTURBANCE 96W (E OF GUAM)

B. 13/1732Z

C. 13.70N

D. 151.60E

E. FIVE/MTSAT

F. T1.0/1.0/INIT OBS

G. IR/EIR

H. REMARKS: 38A/PBO SBC/ANMTN. CNVCTN WRAPS .25 ON LOG10
SPIRAL, YIELDING A DT OF 1.0. MET AND PT ARE UNAVAILABLE. DBO
DT.

I. ADDITIONAL POSITIONS: NONE


CHAPPOTIN

[euro6208]

NWS

THE CIRCULATION EAST OF 150E IS THE SUBJECT OF A TROPICAL CYCLONE
FORMATION ALERT ISSUED BY JTWC. MODELS HAVE DEPICTED THIS
CIRCULATION FOR THE PAST FEW DAYS. THEY HAVE CONSISTENTLY
PREDICTED THAT IT WILL MOVE SLOWLY NORTHWARD. THE CURRENT FORECAST
MODELS SHOW THAT THE CIRCULATION WILL BE NEAR 20N150E LATE
WEDNESDAY. AT THE PRESENT TIME MODELS KEEP THE CIRCULATION FAIRLY
WEAK AND ALL ACTIVITY WILL REMAIN EAST OF THE MARIANAS. AS WITH
ANY SUSPECT AREAS IT IS ADVISED TO REMAIN UP TO DATE ON THE LATEST
INFORMATION.

[Yellow Evan]

Don't know why this hasn't been upped yet. This has maintain well-organized convection and has a closed LLC and 25 knt winds as indicated by a RapidScat pass.

[euro6208]

About 8 hours ago.


000
WWMY80 PGUM 132323
SPSMY

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TIYAN GU
920 AM CHST MON SEP 14 2015

GUZ001>005-PMZ151>154-141100-
GUAM-ROTA-TINIAN-SAIPAN-NORTHERN MARIANAS-MARIANAS COASTAL WATERS-
920 AM CHST MON SEP 14 2015

...TROPICAL DISTURBANCE EAST OF THE MARIANA ISLANDS...

A TROPICAL CYCLONE FORMATION ALERT HAS BEEN ISSUED BY JOINT TYPHOON
WARNING CENTER FOR TROPICAL DISTURBANCE 96W LOCATED ABOUT 405 MILES
EAST-SOUTHEAST OF SAIPAN. FOR MORE INFORMATION ON THE TROPICAL
CYCLONE FORMATION ALERT...SEE THE JTWC BULLETIN ISSUED UNDER WMO
HEADERS WTPN22 PGTW.

COMPUTER MODELS INDICATE TROPICAL DISTURBANCE 96W WILL MOVE TO THE
NORTH OR NORTHWEST OVER THE NEXT FEW DAYS AND COULD AFFECT THE
NORTHERN MARIANA ISLANDS INCLUDING...PAGAN...ALAMAGAN AND AGRIHAN BY
MIDWEEK.

CONDITIONS ARE EXPECTED TO DETERIORATE ACROSS THE FAR NORTHERN
MARIANA ISLANDS WEDNESDAY WITH INCREASING SHOWERS AND THUNDERSTORMS
ALONG WITH GUSTY WINDS AND BUILDING SEAS.

STAY INFORMED ON THE PROGRESS OF TROPICAL DISTURBANCE 96W BY
FOLLOWING THE LATEST STATEMENTS ISSUED BY THE NATIONAL WEATHER
SERVICE ON GUAM. THESE ARE POSTED ON THE WFO GUAM WEB PAGE AT
http://WWW.PRH.NOAA.GOV/GUAM/ (ALL LOWER CASE).

$$

WILLIAMS

[euro6208]

THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 13.7N
151.7E, IS NOW LOCATED NEAR 14.4N 152.0E, APPROXIMATELY 430 NM EAST
OF APRA HARBOR, GUAM. ANIMATED MSI SHOWS DEEP CONVECTION SHEARED
ABOUT 110 NM TO THE WEST OF THE VISIBLY WEAK LLCC. A 140408Z AMSU
MICROWAVE PASS SHOWS WEAK SHALLOW BANDING WRAPPING INTO THE LLCC.
HOWEVER, IT IS POSSIBLE THAT THERE IS ANOTHER LLCC TUCKED UNDER THE
DEEPEST CONVECTION. THIS LEADS TO LOW CONFIDENCE IN THE JTWC
POSITION OF THE SYSTEM AT THIS TIME. UPPER LEVEL ANALYSIS INDICATES
A FAVORABLE ENVIRONMENT WITH 10 TO 15 KNOTS VWS AND GOOD DUAL
CHANNEL OUTFLOW ENHANCED BY A TUTT CELL LOCATED TO THE NORTH. GLOBAL
MODELS INDICATE DEVELOPMENT OF THE SYSTEM OVER THE NEXT 24 HOURS AS
IT TRACKS GENERALLY NORTHWARD. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED
TO BE NEAR 1006 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS HIGH.

[euro6208]

000
WWMY80 PGUM 140921
SPSMY

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TIYAN GU
720 PM CHST MON SEP 14 2015

GUZ001>005-PMZ151>154-150000-
GUAM-ROTA-TINIAN-SAIPAN-NORTHERN MARIANAS-MARIANAS COASTAL WATERS-
720 PM CHST MON SEP 14 2015

...TROPICAL DISTURBANCE STILL MOVING NORTHWARD...

A SLOWLY DEVELOPING TROPICAL DISTURBANCE IS CENTERED ABOUT 400 MILES
EAST OF SAIPAN AND ABOUT 500 MILES EAST-NORTHEAST OF GUAM NEAR
16N152E. THIS SYSTEM CONTINUES MOVING NORTHWARD. SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH THIS SYSTEM REMAIN TO THE EAST OF THE
MARIANAS.

COMPUTER MODELS INDICATE THIS TROPICAL DISTURBANCE WILL MOVE TOWARD
THE NORTH...THEN NORTHWEST DURING THE NEXT FEW DAYS. THIS FORECAST
TRACK CONFINES THE ADVERSE WEATHER AND SEAS CONNECTED WITH THIS
SYSTEM WELL TO THE NORTH OF GUAM...ROTA...TINIAN AND SAIPAN.
CONDITIONS COULD DETERIORATE ACROSS THE FAR NORTHERN MARIANA ISLANDS
ON WEDNESDAY AND WEDNESDAY NIGHT IF THIS DISTURBANCE DEVELOPS AND
TAKES A TURN TOWARD THE WEST AS MODEL GUIDANCE SUGGESTS. THIS MEANS
PAGAN...ALAMAGAN AND AGRIHAN COULD EXPERIENCE SOME HEAVY RAINFALL...
THUNDERSTORMS...GUSTY WINDS AND BUILDING SEAS DURING THIS TIME FRAME.

THE TROPICAL CYCLONE FORMATION ALERT PREVIOUSLY ISSUED BY THE JOINT
TYPHOON WARNING CENTER FOR THIS SYSTEM REMAINS IN EFFECT. FOR MORE
INFORMATION...SEE BULLETINS ISSUED BY THE JTWC UNDER WMO HEADER
WTPN21 PGTW.

STAY INFORMED ON THE PROGRESS OF THIS SYSTEM BY FOLLOWING THE LATEST
STATEMENTS ISSUED BY THE NATIONAL WEATHER SERVICE ON GUAM. THESE ARE
POSTED ON THE WFO GUAM WEB PAGE AT http://WWW.PRH.NOAA.GOV/GUAM/ (ALL LOWER
CASE).

$$

MCELROY

[euro6208]

Both EURO and GFS brings this to a typhoon north of the Marianas with GFS peaking at 963 mb and recurving...

[1900hurricane]

I'd probably give it a renumber now. The circulation is closed and while only at the eastern edge of the convection, isn't completely exposed like it was twelve hours ago.

[1900hurricane]

It looks like subsidence is hampering convective development on the eastern side of the circulation to me.

[wxman57]

Note that the JMA is the official RSMC for the West Pacific, not JTWC. The JMA classified this system as a depression yesterday (TD "b).

http://www.jma.go.jp/en/typh/b.html

[1900hurricane]

Yep, quite aware, which is why I went with the renumber terminology. I don't think JMA does renumbers since they only number their named storms (this one would be 1520 if it were named using their numbering system).

[1900hurricane]

Speaking of JMA, the do expect a named system (next name is Krovanh) by 24 hours.

TD
Issued at 13:05 UTC, 14 September 2015

<Analyses at 14/12 UTC>
Scale -
Intensity -
TD
Center position N15°20'(15.3°)
E149°55'(149.9°)
Direction and speed of movement NW 15km/h(8kt)
Central pressure 1002hPa
Maximum wind speed near the center 15m/s(30kt)
Maximum wind gust speed 23m/s(45kt)

<Forecast for 15/12 UTC>
Intensity -
Center position of probability circle N17°00'(17.0°)
E149°50'(149.8°)
Direction and speed of movement N Slowly
Central pressure 998hPa
Maximum wind speed near the center 18m/s(35kt)
Maximum wind gust speed 25m/s(50kt)
Radius of probability circle 220km(120NM)

[Extratropical94]

20W TWENTY 150914 1200 16.3N 152.5E WPAC 20 1007

Unofficially TD 20W now.