Twenty-Si
Western Pacific
Tropical Depression · WP262026
15.6°N,
151.9°E
Moving west at 8 mph
Max Winds
30 mph
Pressure
1005 mb
Forecast Points
8
Summary
At 10 AM Wednesday Guam time, Tropical Depression Twentysix was about 485 miles east-northeast of Guam, moving west at about 8 mph. Maximum sustained winds were 30 mph (JTWC's one-minute average). The minimum central pressure was 1005 mb (the lower the pressure, the stronger the storm tends to be). JTWC estimated the highest significant wave height (the average of the highest third of the waves) at 12 feet.
Closest approach to land
- Saipan and Tinian: JTWC's forecast track passes about 105 miles from the coast early Friday (4 AM). JTWC's forecast point for Thursday 10 PM: 50 mph winds (tropical storm); tropical-storm-force winds up to about 125 miles from the center on that side.
Distances are measured from straight lines between JTWC's forecast points to the nearest coast. JTWC's wind radii are valid over open water.
JTWC's forecast
JTWC's forecast track takes Twentysix toward the west first, then toward the northwest from Friday morning, then toward the north from Friday night.
JTWC's forecast brings Twentysix to a peak of 125 mph (typhoon) Sunday morning (10 AM), holding near that strength through Monday morning (10 AM).
JTWC's forecast strength (Guam time):
- Wednesday morning (10 AM), warning position: 30 mph (tropical depression)
- Wednesday night (10 PM): 35 mph (tropical depression)
- Thursday morning (10 AM): 40 mph (tropical storm)
- Thursday night (10 PM): 50 mph (tropical storm)
- Friday morning (10 AM): 65 mph (tropical storm)
- Friday night (10 PM): 80 mph (typhoon)
- Saturday morning (10 AM): 100 mph (typhoon)
- Sunday morning (10 AM): 125 mph (typhoon)
- Monday morning (10 AM): 125 mph (typhoon)
Bottom line
- JTWC does not issue watches or warnings for land; each country's weather agency does (for the places above: the National Weather Service office in Guam). Follow their official warnings.
- Peak forecast strength: 125 mph (typhoon), Sunday morning (10 AM).
- JTWC's next warning: Wednesday 7 PM Guam time.
Facts in this summary come from JTWC warning 1 (Joint Typhoon Warning Center) on Tropical Depression 26W (Twentysix), issued 0300 UTC Wednesday, September 30.
Forecast intensity
JTWC forecast maximum sustained winds (mph) by hour.
Satellite Imagery (IR)
CIRA/RAMMB · 30 Sep 02:30 UTC
JTWC Warning #1 30 Sep 00:00 UTC
WTPN32 PGTW 300300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL DEPRESSION 26W (TWENTYSIX) WARNING NR 001//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/291651SEP2026//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.//
RMKS/
1. TROPICAL DEPRESSION 26W (TWENTYSIX) 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:
300000Z --- NEAR 15.6N 151.9E
MOVEMENT PAST SIX HOURS - 270 DEGREES AT 07 KTS
POSITION ACCURATE TO WITHIN 060 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: 15.6N 151.9E
---
FORECASTS:
12 HRS, VALID AT:
301200Z --- 16.0N 150.5E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 24 HR POSIT: 285 DEG/ 09 KTS
---
24 HRS, VALID AT:
010000Z --- 16.4N 148.7E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 170 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
080 NM SOUTHWEST QUADRANT
150 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 280 DEG/ 09 KTS
---
36 HRS, VALID AT:
011200Z --- 16.7N 146.8E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 180 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
110 NM SOUTHWEST QUADRANT
160 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 280 DEG/ 08 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
020000Z --- 16.9N 145.2E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 180 NM NORTHEAST QUADRANT
130 NM SOUTHEAST QUADRANT
120 NM SOUTHWEST QUADRANT
170 NM NORTHWEST QUADRANT
VECTOR TO 60 HR POSIT: 310 DEG/ 02 KTS
---
60 HRS, VALID AT:
021200Z --- 17.2N 144.8E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
015 NM SOUTHWEST QUADRANT
015 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 170 NM NORTHEAST QUADRANT
140 NM SOUTHEAST QUADRANT
120 NM SOUTHWEST QUADRANT
120 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 005 DEG/ 05 KTS
---
72 HRS, VALID AT:
030000Z --- 18.1N 144.9E
MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 075 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 170 NM NORTHEAST QUADRANT
160 NM SOUTHEAST QUADRANT
130 NM SOUTHWEST QUADRANT
140 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 015 DEG/ 07 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
040000Z --- 20.6N 145.7E
MAX SUSTAINED WINDS - 110 KT, GUSTS 135 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 050 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 100 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
080 NM SOUTHWEST QUADRANT
080 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 210 NM NORTHEAST QUADRANT
210 NM SOUTHEAST QUADRANT
180 NM SOUTHWEST QUADRANT
180 NM NORTHWEST QUADRANT
VECTOR TO 120 HR POSIT: 360 DEG/ 08 KTS
---
120 HRS, VALID AT:
050000Z --- 23.7N 145.6E
MAX SUSTAINED WINDS - 110 KT, GUSTS 135 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 060 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 110 NM NORTHEAST QUADRANT
110 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 230 NM NORTHEAST QUADRANT
230 NM SOUTHEAST QUADRANT
190 NM SOUTHWEST QUADRANT
190 NM NORTHWEST QUADRANT
---
REMARKS:
300300Z POSITION NEAR 15.7N 151.6E.
30SEP26. TROPICAL DEPRESSION 26W (TWENTYSIX), LOCATED
APPROXIMATELY 422 NM EAST-NORTHEAST OF ANDERSEN AFB, HAS TRACKED
WESTWARD AT 07 KNOTS OVER THE PAST SIX HOURS. MINIMUM CENTRAL PRESSURE
AT 300000Z IS 1005 MB. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 300000Z IS
12 FEET. NEXT WARNINGS AT 300900Z, 301500Z, 302100Z AND 010300Z. REFER
TO TROPICAL STORM 25W (SURIGAE) WARNINGS (WTPN31 PGTW) FOR SIX-HOURLY
UPDATES.
2. THIS CANCELS AND SUPERCEDES REF A (WTPN21 PGTW 291700).//
NNNN
Products not available for West Pacific storms
- NEXRAD radar — no radar coverage over the open West Pacific.
- Storm-surge inundation — no public storm-surge model for this basin.
- Wind-speed probabilities — JTWC does not publish them.
- Watches and warnings — issued by local agencies (PAGASA, JMA, CWA), not JTWC.
- Reconnaissance aircraft — no routine aircraft reconnaissance in the West Pacific.
- Rapid-intensification and shear diagnostics — SHIPS-based guidance is not published for this basin.
These are data-availability limits for the West Pacific basin, not omissions.
Source: U.S. Navy/Air Force Joint Typhoon Warning Center (JTWC), via the UCAR Tropical Cyclone Guidance Project. JTWC data is in the public domain. · Updated 2026-09-30 02:26 UTC · JMA analysis: Source: Japan Meteorological Agency (10-minute average winds). Satellite imagery: CIRA/RAMMB.