WPAC: SINLAKU - Typhoon

[cycloneye]

Guam-Rota-Tinian-Saipan-
805 AM ChST Sat Apr 11 2026

...FLOOD WATCH IN EFFECT FROM SUNDAY EVENING THROUGH WEDNESDAY
MORNING...

* WHAT...Flash flooding caused by excessive rainfall is possible.

* WHERE...Guam, Rota, Tinian and Saipan.

* WHEN...From Sunday evening through Wednesday morning.

* IMPACTS...Excessive runoff may result in flooding of rivers,
creeks, streams, and other low-lying and flood-prone locations.

* ADDITIONAL DETAILS...
- Tropical Storm Sinlaku is slowly approaching the Marianas and
is expected to strengthen, possibly crossing Guam as a
typhoon possibly as early as Monday morning.

This is expected to produce 15 to 20 inches of rainfall
between Sunday night and Wednesday for Guam and Rota, with 8
to 15 inches expected for Tinian and Saipan. Widespread
showers, torrential rain and scattered thunderstorms are
expected as Sinlaku moves through the Marianas Monday through
Wednesday morning.

As showers are likely to persist, consistent rainfall is
likely to
produce flash floods and saturate the soils enough to
increase the
chance for mudslides over central to southern Guam.
- http://www.weather.gov/safety/flood

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Residents of the Marianas need to closely monitor this developing
situation as flash flood warnings will likely be issued later.

If living near streams and rivers, move items away from stream and
river banks. Make sure storm drains nearby are not clogged,
especially If living at low-lying areas.

[ljmac75]

 https://x.com/AndyHazelton/status/2042662207599579260

18z run with a Cat 5 over Guam as well, though with the right front quadrant missing the island.

[DorkyMcDorkface]

Pretty neat
 https://x.com/BackpirchCrew/status/2042735965559546368

[doomhaMwx]

Well on its way to significant intensification with shear likely to subside tomorrow and with microwave already showing a mid level inner core.

Edit: The MW in question.

MW pass a couple of hours before that one.

[doomhaMwx]

Nearby Chuuk PTKK airport reported a max gust of 56 kts (104 kph) and a min MSLP of 982.2 mb.

[cycloneye]

04W SINLAKU 260411 0000 8.5N 151.5E WPAC 70 977

A. 04W (SINLAKU)

B. 10/2330Z

C. 8.4N

D. 151.4E

E. THREE/HIMAWARI-9

F. T4.5/4.5

G. IR/EIR/VIS/SSMIS

H. REMARKS...LLCC EMBEDDED IN CDG RESULTS IN A DT OF 5.0. 1932Z
SSMIS PASS SHOWED TIGHT CORE WITH NASCENT EYE AND INNER BAND SUBSIDENCE
RING. CDO TOPS AS COLD AS -92 C. UPR-LVL OUTFLOW EXCELLENT S AND W QUADS
AND GOOD ELSEWHERE. MET=4.0 AND PT=4.5. FT BASED ON PT DUE TO UNCERTAINTY
OF EXACT CENTER LOCATION.

I. ADDL POSITIONS

10/1932Z 8.3N 151.4E SSMIS

[cycloneye]

Here we go. Updated Best Track up to 75kt.

04W SINLAKU 260411 0000 8.5N 151.5E WPAC 75 972

[cycloneye]

 https://x.com/BackpirchCrew/status/2042770303886008461

[cycloneye]

Many cat 5 ensemble members of google deepmind.

[cycloneye]

A Typhoon Watch has now been issued for Guam, Rota, Tinian and
Saipan.

[cycloneye]

Thru Guam as cat 4.

[mrbagyo]

Sinlaku has that convective blob on the NE.

[Guamphoon]

Thru Guam as cat 4.

Well that is not optimal. Entire island is battening down. Reservoirs getting filled. Shutters Closed. Trees trimmed. Still hoping we dodge it.

But will give you guys updates if it hits.

[dexterlabio]

Early season major typhoon threat to Guam is hallmark El Niño IMO.

[cycloneye]

A. 04W (SINLAKU)

B. 11/1130Z

C. 9.4N

D. 150.6E

E. THREE/HIMAWARI-9

F. T4.5/5.0

G. IR/EIR/SWIR

H. REMARKS...LLCC EMBEDDED IN LG RESULTS IN A DT OF 4.5. THE MET EQUALS
4.5 BASED ON A DEVELOPING 24-HOUR TREND AND THE PT AGREES. THE FT IS
BASED ON THE MET DUE TO UNCERTAINTY IN THE EXACT LLCC LOCATION.

I. ADDL POSITIONS

NIL


...LINER

[cycloneye]

JTWC is up to cat 2:

04W SINLAKU 260411 1200 9.0N 151.1E WPAC 85 965

[Hurricane2022]

 https://x.com/i/status/2042893619808370989

[Hayabusa]

JTWC is up to cat 2:

04W SINLAKU 260411 1200 9.0N 151.1E WPAC 85 965

It looked like it was going for a major typhoon 12 hours earlier

[mrbagyo]

Must be able to pop that eye open within the next 12 hrs.

[sasha_B]

Definitely looks like an eye starting to take shape - there's been a fairly distinct warmer spot near the center of the CDO over the past 2 hours (though "warmer" in this case still mostly still means CMG).