819
AXPQ20 PGUM 120139
TWDPQ
TROPICAL WEATHER DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
1139 AM CHST MON JAN 12 2026
TROPICAL WEATHER DISCUSSION FOR THE WESTERN NORTH PACIFIC BETWEEN
THE EQUATOR AND 25N FROM 130E TO 180. THE FOLLOWING INFORMATION IS
BASED ON RECENT SATELLITE IMAGERY/DATA, WEATHER OBSERVATIONS, RADAR,
AND METEOROLOGICAL ANALYSIS.
..SPECIAL FEATURES
TROPICAL AND MONSOON DISTURBANCES...
A DEVELOPING TROPICAL DISTURBANCE, JTWC INVEST 91W, IS CENTERED SSE
OF YAP PROPER NEAR 3.7N 139.0E. 91W IS MOVING NW AND BECOMING MORE
ORGANIZED AS IT APPROACHES PALAU. NUMEROUS TO WIDESPREAD SHOWERS AND
ISOLATED THUNDERSTORMS ARE FOUND OVER PALAU FROM 134E, EXTENDING E
TO 141E, FROM 4N TO 8N. A BAND OF CONVERGENCE N OF THE CIRCULATION IS
GENERATING SCATTERED TO NUMEROUS SHOWERS FROM 137E TO 144E FROM 8N TO
11N. INVEST 91W IS EXPECTED TO MOVE WNW OVER THE NEXT FEW DAYS,
PASSING NEAR PALAU. 91W IS EXPECTED TO SLOWLY STRENGTHEN AS WELL,
POSSIBLY BECOMING A TROPICAL DEPRESSION LATE IN THE WEEK NEAR 130E.
91W WILL BE MONITORED CLOSELY FOR ANY INDICATIONS OF MORE RAPID
DEVELOPMENT.
..OTHER WEATHER SYSTEMS
NEAR EQUATORIAL TROUGH...
THE NEAR EQUATORIAL TROUGH (NET) EXTENDS ENE ACROSS 3N130E TO INVEST
91W, THEN TURNS SE TO BEYOND THE EQUATOR NEAR 150E. SW OF 91W,
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE FOUND FROM THE
EQUATOR TO 5N. NUMEROUS TO WIDESPREAD SHOWERS ARE FOUND WITH INVEST
91W AND THE NET. E OF 91W, ONLY SPOTTY CLOUDS AND SHOWERS ARE FOUND
WITH THE NET. AS INVEST 91W MOVES WNW, IT WILL DRAG THE NET ALONG
WITH IT. THE NET IS EXPECTED TO STRENGTHEN AS WELL AS 91W SLOWLY
DEVELOPS.
TRADE-WIND TROUGHS...
THERE IS A WEAK TRADE-WIND TROUGH FOUND W OF WENO, CHUUK, EXTENDING
NE FROM 6N145E TO END NEAR 13N151E. MOST OF THE CONVECTION SEEN W OF
THE TROUGH IS DUE TO A BAND OF CONVERGENCE ASSOCIATED WITH INVEST
91W. THE TROUGH IS EXPECTED TO MOVE W OVER THE NEXT COUPLE OF DAYS
THEN TURN SW. AS THE TROUGH MOVES OVER THE CONVERGENCE, IT IS
EXPECTED TO ENHANCE THE CONVERGENCE AND CONVECTION ASSOCIATED WITH
THE BAND.
ANOTHER TRADE-WIND TROUGH IS FOUND JUST E OF KOSRAE, EXTENDING NNE
FROM NEAR 1N161E TO END W OF KWAJALEIN NEAR 9N167E. THIS TROUGH IS
ENHANCING CONVECTION E OF KOSRAE, PRODUCING SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS. THE TROUGH WILL CONTINUE TO MOVE W,
INTERACTING WITH THE ITCZ AND ENHANCING CONVECTION FOR KOSRAE AND
POHNPEI STATES.
TRADE-WIND SURGE...
THE TRADE-WIND SURGE IS NOW FOUND FROM 155E TO 170E, FROM 15N TO
25N. WINDS ARE UP TO 40 MPH (35 KNOTS) WITH THIS SURGE, MAINLY ALONG
20N. THE MID-LATITUDE HIGH GENERATING THIS SURGE WILL CONTINUE TO
MOVE E, WITH THE SURGE RETREATING E AS IT PROGRESSES. ANOTHER
BUILDING MID-LATITUDE HIGH PRESSURE SYSTEM HAS MOVED OF THE ASIAN
CONTINENT AND IS EXPECTED TO PRODUCE ANOTHER STRONG SURGE OVER THE
REGION.
OTHER SYSTEMS...
A COLD FRONT ENTERS THE REGION NEAR MINAMI TORISHIMA AT 25N154E,
EXTENDING SE TO THE N CNMI NEAR 18N146E. IT THEN CONTINUES AS A
SHEAR LINE TO END NEAR 10N135E. EXTENSIVE CLOUDS WITH SCATTERED TO
NUMEROUS SHOWERS ARE FOUND UP TO 250 MILES NW OF THE COLD FRONT.
PATCHY CLOUDS AND SHOWERS ARE FOUND NW OF THE SHEAR LINE. THE FRONT
WILL CONTINUE TO MOVE E OVER THE COMING DAYS WHILE TRANSITIONING TO
A SHEAR LINE. THE N PORTION OF THE SHEAR LINE WILL MOVE E WITH
LITTLE CHANGE IN INTENSITY WHILE THE SOUTHERN PORTION WEAKENS AND
MOVES SLOWLY ESE.
..ITCZ
A DEVELOPING ITCZ MEANDERS E FROM AROUND FARAULEP NEAR 5N145E,
EXTENDING SE ACROSS WENO, CHUUK, TO S OF POHNPEI NEAR 4N158E. THE
ITCZ THEN TURNS ENE TO N OF MAJURO NEAR 9N171E, WHERE IT TURNS SE TO
BEYOND THE DATE LINE NEAR 5N. SCATTERED TO NUMEROUS SHOWERS AND
ISOLATED THUNDERSTORMS ARE FOUND ALONG THE ITCZ FROM FARAULEP TO SE
OF WENO. ISOLATED SHOWERS ARE FOUND FROM SE OF WENO TO SW OF KOSRAE.
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE FOUND ALONG THE
REMAINDER OF THE ITCZ TO BEYOND THE DATE LINE. A WEAK TRADE-WIND
TROUGH IS INTERACTING WITH THE ITCZ E OF KOSRAE TO ENHANCE
CONVECTION. THE ITCZ WILL CONTINUE TO MEANDER N AND S OVER THE
REGION, WITH WEAK TRADE-WIND TROUGHS MOVING THROUGH TO ENHANCE
CONVECTION. MODELS FAVOR STRENGTHENING OF THE ITCZ FOR THE NEXT
COUPLE OF DAYS BEFORE IT BEGINS TO WEAKEN.
KLEESCHULTE
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