WPAC: 01W - Post-Tropical

[euro6208]

GFS continues with the fast development. Closer to Guam. The Marshalls better watchout.

[xtyphooncyclonex]

GFS has a TS in 48-60 hours, which is more sensible. Remains in within that intensity before its closest approach to Guam. Enters the PAR as Amang (just like Mekkhala), intensifies quickly, bottoms out at 942 mb before slowing down, turning NW and weakening.

[TyphoonNara]

GFS has a TS in 48-60 hours, which is more sensible. Remains in within that intensity before its closest approach to Guam. Enters the PAR as Amang (just like Mekkhala), intensifies quickly, bottoms out at 942 mb before slowing down, turning NW and weakening.

https://i.imgur.com/JEyQnb2.png

Even though the GFS frequently exaggerates things, I think we have a decent chance of seeing a January typhoon this year.

[cycloneye]

12z ECMWF is a bit stronger east of Guam's longitud.

[xtyphooncyclonex]

[cycloneye]

First warning from JTWC:

WTPN32 PGTW 042100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE WARNING//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/040521ZJAN2019//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.//
RMKS/
1. TROPICAL DEPRESSION 01W (ONE) WARNING NR 001
02 ACTIVE TROPICAL CYCLONES IN NORTHWESTPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
041800Z --- NEAR 4.8N 174.0E
MOVEMENT PAST SIX HOURS - 320 DEGREES AT 13 KTS
POSITION ACCURATE TO WITHIN 025 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
WIND RADII VALID OVER OPEN WATER ONLY
REPEAT POSIT: 4.8N 174.0E
---
FORECASTS:
12 HRS, VALID AT:
050600Z --- 5.3N 173.8E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 24 HR POSIT: 325 DEG/ 04 KTS
---
24 HRS, VALID AT:
051800Z --- 6.0N 173.3E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 030 NM NORTHEAST QUADRANT
000 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 305 DEG/ 04 KTS
---
36 HRS, VALID AT:
060600Z --- 6.5N 172.6E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 295 DEG/ 07 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
061800Z --- 7.1N 171.4E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
010 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 295 DEG/ 11 KTS
---
72 HRS, VALID AT:
071800Z --- 8.8N 167.3E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT
010 NM SOUTHEAST QUADRANT
010 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 285 DEG/ 15 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
081800Z --- 10.3N 161.3E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
010 NM SOUTHWEST QUADRANT
070 NM NORTHWEST QUADRANT
VECTOR TO 120 HR POSIT: 280 DEG/ 17 KTS
---
120 HRS, VALID AT:
091800Z --- 11.6N 154.4E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 000 NM NORTHEAST QUADRANT
010 NM SOUTHEAST QUADRANT
010 NM SOUTHWEST QUADRANT
000 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
130 NM NORTHWEST QUADRANT
---
REMARKS:
042100Z POSITION NEAR 4.9N 174.0E.
TROPICAL DEPRESSION 01W (ONE), LOCATED APPROXIMATELY 217 NM
SOUTHEAST OF MAJURO, MARSHALL ISLANDS, HAS TRACKED NORTHWESTWARD AT
13 KNOTS OVER THE PAST SIX HOURS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT
041800Z IS 9 FEET. NEXT WARNINGS AT 050300Z, 050900Z, 051500Z AND
052100Z. REFER TO TROPICAL STORM 36W (PABUK) WARNINGS (WTPN31 PGTW)
FOR SIX-HOURLY UPDATES.
2. THIS CANCELS AND SUPERSEDES REF A (WTPN21 PGTW 040530).//

[euro6208]

Favorable environment throughout the forecast.

WDPN31 PGTW 042100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 01W (ONE)
WARNING NR 001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL DEPRESSION (TD) 01W (ONE), LOCATED APPROXIMATELY 217 NM
SOUTHEAST OF MAJURO, MARSHALL ISLANDS, HAS TRACKED NORTHWESTWARD AT
13 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY SHOWS PERSISTENT CONVECTION OVER AN OBSCURED LOW
LEVEL CIRCULATION. A WEAK AND FRAGMENTED FORMATIVE BAND IS ALSO
EVIDENT ALONG THE SOUTHERN FLANK. THE INITIAL POSITION IS PLACED WITH
FAIR CONFIDENCE BASED ON THE EIR LOOP AND LINED UP WITH A SEMI-CLOSED
CIRCULATION FEATURE IN THE 041503Z 36GHZ SSMIS MICROWAVE IMAGE. THE
INITIAL INTENSITY OF 25 KNOTS IS BASED ON THE DVORAK INTENSITY
ESTIMATES OF T1.0 AND T1.5 FROM KNES AND PGTW AND IS CONSISTENT WITH
THE EIR CONVECTIVE STRUCTURE. THE INITIAL POSITION AND INTENSITY ARE
ALSO CONSISTENT WITH NEARBY SURFACE OBSERVATIONS. ENVIRONMENTAL
ANALYSIS INDICATES A MARGINALLY FAVORABLE ENVIRONMENT WITH LOW TO
MODERATE (15 TO 20 KNOT) VERTICAL WIND SHEAR (VWS) OFFSET BY GOOD
RADIAL OUTFLOW WITH A STRONG POLEWARD BIAS. SEA SURFACE TEMPERATURES
ARE VERY CONDUCIVE AT 28-30 CELSIUS. THE CYCLONE IS TRACKING ALONG
THE SOUTHWEST PERIPHERY OF THE SUBTROPICAL RIDGE (STR) TO THE
NORTH-NORTHEAST.
3. FORECAST REASONING.
A. THIS IS THE INITIAL PROGNOSTIC REASONING MESSAGE AND SETS THE
FORECAST PHILOSOPHY FOR THIS SYSTEM.
B. TD 01W WILL CONTINUE TRACKING NORTHWESTWARD TOWARD A BREAK IN
THE STR. AFTER TAU 48 AND TRACKING OVER MAJURO, A SECONDARY STR TO
THE NORTHWEST WILL ASSUME STEERING AND DRIVE THE SYSTEM ON A MORE
WEST-NORTHWESTWARD DIRECTION AND, BY TAU 72, WILL JUST HAVE TRACKED
OVER KWAJALEIN ATOLL. DECREASING VWS AND IMPROVING POLEWARD OUTFLOW
WILL FUEL A SLOW INTENSIFICATION TO 45 KNOTS BY TAU 72.
C. AFTER TAU 72, TD 01W WILL CONTINUE ON A WEST-NORTHWESTWARD
TRACK TOWARD GUAM UNDER THE SECONDARY STR. THE FAVORABLE
ENVIRONMENTAL CONDITIONS WILL PERSIST AND PROMOTE FURTHER
INTENSIFICATION, REACHING 55 KNOTS (POSSIBLY HIGHER) BY TAU 120. THE
AVAILABLE NUMERICAL GUIDANCE IS IN OVERALL GOOD AGREEMENT WITH THE
TRACK WITH CTCX AS THE NOTABLE OUTLIER ON THE LEFT MARGIN OF THE
MODEL ENVELOPE. HOWEVER, DUE TO THE FORMATIVE NATURE OF THE SYSTEM,
THERE IS LOW CONFIDENCE IN ALL PORTIONS OF THE FIRST JTWC WARNING
TRACK THAT IS LAID JUST RIGHT OF CONSENSUS TO OFFSET THE UNLIKELY
CTCX SOLUTION.//
NNNN

[euro6208]

000
WTPQ32 PGUM 042147
TCPPQ2

BULLETIN
Tropical Depression 01W Advisory Number 1
National Weather Service Tiyan GU WP332019
747 AM ChST Sat Jan 5 2019

...TROPICAL DEPRESSION 01W FORMS EAST-SOUTHEAST OF MAJURO...

CHANGES WITH THIS ADVISORY
--------------------------
A Tropical Storm Watch is being issued for Mili, Majuro, Ailinglaplap
and Kwajalein in the Republic of the Marshall Islands.

WATCHES AND WARNINGS
--------------------
A Tropical Storm Watch is being issued for Mili, Majuro, Ailinglaplap
and Kwajalein in the Republic of the Marshall Islands.

A Tropical storm watch means that damaging winds of 39 mph or more
are possible within 36 to 48 hours.


SUMMARY OF 700 AM CHST...2100 UTC...INFORMATION
----------------------------------------------
Location...4.9N 174.0E

About 180 miles east-southeast of Mili
About 245 miles southeast of Majuro
About 385 miles east-southeast of Ailinglaplap
About 405 miles southeast of Wotje
About 500 miles east-southeast of Kwajalein
About 760 miles east of Kosrae
About 1100 miles east of Pohnpei
About 2075 miles east-southeast of Guam

Maximum sustained winds...30 mph
Present movement...northwest...320 degrees at 15 mph

DISCUSSION AND OUTLOOK
----------------------
At 700 AM CHST...2100 UTC...the center of Tropical Depression
01W was located near Latitude 4.9 degrees North and Longitude
174.0 degrees East. 01W is moving northwest at 15 mph. It is
expected to turn more to the west-northwest with a decrease in
forward speed over the next few days.

Maximum sustained winds are 30 mph. 01W is forecast to intensify
through tonight possibly becoming a tropical storm on Sunday.

NEXT ADVISORY
-------------
An intermediate advisory will be issued by the National Weather
Service at 1100 AM followed by the next scheduled advisory
at 200 PM this afternoon.

$$

Nierenberg

[wxman57]

I'm not seeing anything that qualifies this as a depression. JMA hasn't mentioned it yet. It's a disturbance, of course. GFS is much more bullish on development than the EC, which develops a weak TC then dissipates it east of the Philippines by the 14th. I find it hard to believe the GFS solution of a strong typhoon striking the Philippines on the 15th.

[mrbagyo]

Premature renumbering by JTWC.
How is this a depression?

[euro6208]

GFS, ECMWF, and NAVGEM recognizes a newly developed Tropical
Depression 01W and are bringing this developing circulation to the
north of Pohnpei and Chuuk through the next several days. A
Tropical Storm Watch has been issued for Majuro, Mili, Ailinglaplap
and Kwajalein in the Republic of the Marshall Islands as TD01W
remains nearby most of these Marshall Islands this weekend. Now,
computer guidance intensifies TD01W in the coming days as it drives
NW and away from the Marshall Islands, yet winds, seas and rainfall
will elevate near and above respective FSM and Marshall States in
the path of TD01W. Hence, we will continue to provide updates as we
collaborate coordination efforts with JTWC about this developing
tropical system.

[TyphoonNara]

It seems 90W is struggling for some reason.

[euro6208]

WDPN31 PGTW 050300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 01W (ONE)
WARNING NR 002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL DEPRESSION (TD) 01W (ONE), LOCATED APPROXIMATELY 164 NM
EAST-SOUTHEAST OF MAJURO, MARSHALL ISLANDS, HAS TRACKED
NORTH-NORTHWESTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED
MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS PERSISTENT FLARING
CONVECTION OVER AN OBSCURED LOW LEVEL CIRCULATION (LLC). WEAK
FORMATIVE BANDS ARE ALSO EVIDENT ALONG THE NORTHEAST AND SOUTHERN
FLANKS. THE INITIAL POSITION IS PLACED WITH LOW CONFIDENCE BY
EXTRAPOLATING FROM THE FORMATIVE BANDS TOWARD THE LLC. THE INITIAL
INTENSITY OF 25 KNOTS IS BASED ON THE DVORAK INTENSITY ESTIMATE OF
T1.5/25KTS FROM PGTW. THE INITIAL POSITION AND INTENSITY ARE ALSO
CONSISTENT WITH NEARBY SURFACE OBSERVATIONS. ENVIRONMENTAL ANALYSIS
INDICATES A MARGINALLY FAVORABLE ENVIRONMENT WITH LOW TO MODERATE (15
TO 20 KNOT) VERTICAL WIND SHEAR (VWS) OFFSET BY GOOD RADIAL OUTFLOW
WITH A STRONG POLEWARD BIAS. SEA SURFACE TEMPERATURES ARE VERY
CONDUCIVE AT 28-30 CELSIUS. THE CYCLONE IS TRACKING ALONG THE
SOUTHWEST PERIPHERY OF THE SUBTROPICAL RIDGE (STR) TO THE
NORTH-NORTHEAST.
3. FORECAST REASONING.
A. THERE IS NO SIGNIFICANT CHANGE TO THE THE FORECAST PHILOSOPHY
FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. TD 01W WILL CONTINUE TRACKING NORTHWESTWARD, INITIALLY AT A
SLOW SPEED, TOWARD A BREAK IN THE STR. AFTER TAU 48 IN THE VICINITY
OF MAJURO, A SECONDARY STR TO THE NORTHWEST WILL ASSUME STEERING AND
DRIVE THE SYSTEM ON A MORE WEST-NORTHWESTWARD DIRECTION AND, BY TAU
72, WILL BE IN THE VICINITY OF KWAJALEIN ATOLL. DECREASING VWS AND
IMPROVING POLEWARD OUTFLOW WILL FUEL A SLOW INTENSIFICATION TO 45
KNOTS BY TAU 72.
C. AFTER TAU 72, TD 01W WILL CONTINUE ON A WEST-NORTHWESTWARD
TRACK TOWARD GUAM UNDER THE SECONDARY STR. THE FAVORABLE
ENVIRONMENTAL CONDITIONS WILL PERSIST AND PROMOTE FURTHER
INTENSIFICATION, REACHING 55 KNOTS (POSSIBLY HIGHER) BY TAU 120. THE
AVAILABLE NUMERICAL GUIDANCE IS IN OVERALL GOOD AGREEMENT WITH THE
TRACK WITH CTCX AS THE NOTABLE OUTLIER ON THE LEFT MARGIN OF THE
MODEL ENVELOPE. HOWEVER, DUE TO THE FORMATIVE NATURE OF THE SYSTEM
AND THE UNCERTAINTY IN THE INITIAL POSITION, THERE IS LOW CONFIDENCE
IN ALL PORTIONS OF THE FIRST JTWC WARNING TRACK THAT IS LAID JUST
RIGHT OF CONSENSUS TO OFFSET THE UNLIKELY CTCX SOLUTION.//
NNNN

[xtyphooncyclonex]

Really does not look like a TD, not even close. Development is likely, but it would take place in a matter of days rather than hours.

Anything could happen. However, this should remain a TD or less for the next 120 hours. After that, there's more room for intensification---unless shear impedes it like the previous west-oriented storms.

[Hayabusa]

JTWC is also frustrated about the recent failure of invests that they upgraded 90W

[xtyphooncyclonex]

Wow, the latest GFS is even stronger through hour 156..... It keeps it as a minimal TD or less throughout the first 120 hours. Hour 132 is when things start ramping up.

We all know what happened to the other invests, lol

[TyphoonNara]

Some new bursts of convection.

[euro6208]

Weaker at peak and JTWC is honest on the latest Dvorak fix. Let's see what they will do.


WDPN31 PGTW 050900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 01W (ONE) WARNING
NR 003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL DEPRESSION (TD) 01W (ONE), LOCATED APPROXIMATELY 84 NM
EAST OF MILI, HAS TRACKED NORTHWESTWARD AT 08 KNOTS (KTS) OVER THE
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS
FLARING CONVECTION AROUND AN ILL-DEFINED, OBSCURED LOW LEVEL
CIRCULATION (LLC). THE INITIAL POSITION IS PLACED WITH LOW
CONFIDENCE BY EXTRAPOLATING FROM A 050536Z SSMIS 37 GHZ MICROWAVE
IMAGE WHICH SHOWS A HINT OF FORMATIVE BANDING WRAPPING TOWARDS THE
LLC. THE INITIAL INTENSITY OF 25 KNOTS IS BASED ON 6-HOUR OLD PGTW
DVORAK CURRENT INTENSITY ESTIMATES OF T1.5/25KTS. HOWEVER, THE MOST
RECENT PGTW DVORAK FIX WAS TOO WEAK FOR DVORAK. THE ENVIRONMENT IS
MARGINALLY FAVORABLE WITH LOW (10-15 KT) VERTICAL WIND SHEAR, POOR
OUTFLOW, AND WARM (29-30 CELSIUS) SEA SURFACE TEMPERATURE. THE
CYCLONE IS TRACKING SLOWLY NORTHWESTWARD TOWARD A BREAK IN A
SUBTROPICAL RIDGE (STR) TO THE NORTH.
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. TD 01W WILL CONTINUE TRACKING SLOWLY NORTHWESTWARD TOWARD THE
BREAK IN THE STR UNTIL TAU 48 WHEN THE STR WILL BUILD TO THE NORTH
AND TURN TD 01W WEST-NORTHWESTWARD. SLIGHTLY IMPROVED OUTFLOW WILL
ENABLE SLOW INTENSIFICATION TO 35 KNOTS BY TAU 36 AND STEADY
INTENSITY THROUGH TAU 72. TD 01W WILL PASS NEAR KWAJALEIN PRIOR TO
TAU 72.
C. AFTER TAU 72, TD 01W WILL CONTINUE ON A WEST-NORTHWESTWARD
TRACK TOWARD GUAM. MARGINALLY FAVORABLE ENVIRONMENTAL CONDITIONS
WILL PERSIST AND PROMOTE SOME ADDITIONAL INTENSIFICATION TO 40 KNOTS
(POSSIBLY HIGHER) BY TAU 120. NUMERICAL GUIDANCE IS IN POOR
AGREEMENT BUT ALL MEMBERS SHOW A GENERALLY WESTWARD TO WEST-
NORTHWESTWARD TRACK. THE MOST RECENT MODEL DATA SHOWED A SIGNIFICANT
SOUTHWARD SHIFT IN THE CONSENSUS TRACK. THIS SHIFT IS LARGELY DUE TO
THE ECMWF TRACKER, A NOTABLE SOUTHERN OUTLIER. THE JTWC FORECAST
TRACK CLOSELY FOLLOWS THE PREVIOUS TRACK. IF THE CONSENSUS TRACK
REMAINS FURTHER SOUTH, IT IS VERY LIKELY THE JTWC TRACK FORECAST
WILL SHIFT. BASED ON HIGH UNCERTAINTY IN THE INITIAL POSITION AND
MODEL GUIDANCE, THERE IS LOW CONFIDENCE IN THE JTWC TRACK FORECAST.//
NNNN

[xtyphooncyclonex]

Let's not rule out development and further intensification, but take the GFS runs with a grain of salt----for now. Personally, I expect this to remain at TD strength or below for the next five days or so. However, conditions are relatively favorable and would benefit the system if its structure catches up and improves.

[doomhaMwx]

Too bad the latest ASCAT pass missed the center...