987
AXPQ20 PGUM 130145
TWDPQ
TROPICAL WEATHER DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
1145 AM CHST TUE JAN 13 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, INVEST 91W, IS EMBEDDED ALONG THE
NEAR EQUATORIAL TROUGH (NET), CENTERED NEAR 4.0N 136.4E. NUMEROUS TO
WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS ARE FOUND IN A BROAD
AREA AROUND 580 MILES SW THROUGH NE OF THE CENTER, WITH A NARROW
BAND OF SCATTERED SHOWERS SEEN SE OF THE CENTER. TO THE SW OF 91W, A
SURFACE TROUGH IS ENHANCING CONVECTION S OF 5N. INVEST 91W IS
EXPECTED TO CONTINUE TO MOVE WNW OVER THE NEXT FEW DAYS AS IT SLOWLY
STRENGTHENS, POSSIBLY BECOMING A TROPICAL DEPRESSION NEAR 130E. THIS
PATH WILL TAKE INVEST 91W S OF PALAU WEDNESDAY MORNING. CONVECTION
IS EXPECTED TO CONSOLIDATE AS 91W PROGRESSES. 91W WILL BE MONITORED
CLOSELY FOR ANY INDICATIONS OF MORE RAPID DEVELOPMENT. ADDITIONAL
INFORMATION FOR YAP AND PALAU IS AVAILABLE IN A SPECIAL WEATHER
STATEMENT (SPSPQ2) UNDER WMO HEADER WWPQ82 PGUM.
..OTHER WEATHER SYSTEMS
NEAR EQUATORIAL TROUGH...
THE NET EXTENDS SE ACROSS 6N130E INTO INVEST 91W, THEN CONTINUES ESE
TO BEYOND THE EQUATOR NEAR 150E. A BAND OF CONVERGENCE E OF 91W AND
N OF THE NET IS GENERATING SCATTERED TO NUMEROUS SHOWERS AND
ISOLATED THUNDERSTORMS IN A 260 MILE WIDE BAND FROM 10N141E TO
3N151E. AS INVEST 91W CONTINUES MOVING WNW, IT WILL PULL THE NET
ALONG WITH IT, AS WELL AS THE BAND OF CONVERGENCE. CONVECTION
ASSOCIATED WITH THIS CONVERGENCE WILL APPROACH YAP AND PALAU OVER
THE NEXT COUPLE OF DAYS.
SURFACE TROUGHS...
A SURFACE TROUGH EXTENDS SW FROM INVEST 91W TO BEYOND 130E NEAR 1N.
THIS TROUGH IS ENHANCING CONVECTION ASSOCIATED WITH 91W, S OF 5N.
THIS TROUGH WILL CONTINUE ROTATING AROUND INVEST 91W, ENHANCING
CONVECTION AS IT PROGRESSES. LITTLE CHANGE IN INTENSITY IS EXPECTED.
TRADE-WIND TROUGHS...
A PAIR OF TRADE-WIND TROUGHS ARE FOUND OVER EASTERN MICRONESIA. THE
FIRST IS FOUND E OF WENO, CHUUK, EXTENDING NW FROM 4N157E TO END
NEAR 9N151E. A NARROW BAND OF ISOLATED SHOWERS AND THUNDERSTORMS IS
FOUND JUST SW OF WENO. THE TROUGH IS EXPECTED TO MOVE WSW OVER THE
NEXT FEW DAYS, WEAKENING AS IT PROGRESSES.
THE SECOND TRADE-WIND TROUGH IS FOUND BETWEEN KOSRAE AND KWAJALEIN,
EXTENDING NW FROM NEAR 3N167E TO END NEAR 10N163E. N OF KOSRAE, THE
TROUGH IS GENERATING A COUPLE NARROW BANDS OF SCATTERED SHOWERS AND
ISOLATED THUNDERSTORM N OF KOSRAE AND SW OF KWAJALEIN. THE S PORTION
OF THE TROUGH, IS INTERACTING WITH THE ITCZ TO GENERATE SCATTERED TO
NUMEROUS SHOWERS OVER AND SE OF KOSRAE TO SW OF AILINGLAPLAP. THE
TROUGH WILL MOVE WSW OVER THE COMING DAYS, DRAGGING THE W END OF THE
ITCZ WITH IT. INITIALLY, THE TROUGH WILL STRENGTHEN A BIT, THEN
BEGIN TO WEAKEN AS IT MOVES INTO A WEAK RIDGE THAT HAS DEVELOPED W
OF THE NET AND INVEST 91W.
TRADE-WIND SURGE...
A TRADE-WIND SURGE FOUND FROM 170E TO BEYOND THE DATE LINE FROM 17N
TO 22N. THIS SURGE IS WEAKENING AND SHIFTING E AS THE MID-LATITUDE
HIGH PRESSURE SYSTEM THAT IS PRODUCING CONTINUES TO MOVE E. THE
SURGE WILL LIKELY BE E OF THE DATE LINE WITHIN THE NEXT 24 HOURS.
A NEW TRADE-WIND SURGE IS FOUND FARTHER W, FROM 7N TO 19N BETWEEN
JUST W OF THE MARIANAS TO BEYOND 130E. THIS SURGE IS BEING PRODUCED
BY A STRONG, BUILDING MID-LATITUDE HIGH PRESSURE SYSTEM MOVING E
THAT IS CURRENTLY PASSING S OF JAPAN. THIS SURGE IS CURRENTLY
ENHANCING CONVERGENCE ASSOCIATED WITH INVEST 91W. THE SURGE IS ALSO
RESPONSIBLE FOR WEAKENING A SHEAR LINE THAT WAS OVER THE PHILIPPINE
SEA. THE SURGE WILL PROGRESS E AS THE HIGH MOVES E IN THE COMING
DAYS.
OTHER SYSTEMS...
A COLD FRONT ENTERS THE REGION NEAR 25N165E, EXTENDING WSW TO S OF
MINAMI TORISHIMA NEAR 21N154E. IT THEN CONTINUES AS A DECAYING SHEAR
LINE TO END NEAR 13N140E. THIS COLD FRONT WILL CONTINUE MOVING E AS
IT WEAKENS AND TRANSITIONS INTO A SHEAR LINE. THE SHEAR LINE HAS
LOST MOST OF ITS DEFINITION AS IT IS BEING TORN APART BY A
DEVELOPING TRADE-WIND SURGE. SCATTERED TO NUMEROUS SHOWERS ARE FOUND
UP TO 350 MILES N OF THE FRONT. ONLY DIFFUSE CLOUDS AND SPOTTY
SHOWERS ARE FOUND ALONG THE SHEAR LINE. THE SHEAR LINE WILL CONTINUE
TO DISSIPATE OVER THE NEXT DAY OR TWO.
..ITCZ
THE ITCZ HAS DISSIPATED W OF 160E DUE TO A WEAK SURFACE RIDGE
BUILDING IN BEHIND INVEST 91W. THE ITCZ HAS STRENGTHENED FROM KOSRAE
E TO BEYOND THE DATE LINE. IT EXTENDS E FROM S OF KOSRAE NEAR 4N163E
TO BEYOND THE DATE LINE NEAR 5N. SCATTERED TO NUMEROUS SHOWERS ARE
FOUND ALONG THE ITCZ. A TRADE-WIND TROUGH BETWEEN KOSRAE AND
KWAJALEIN IS ENHANCING CONVECTION NEAR KOSRAE TO PRODUCE ISOLATED
THUNDERSTORMS ALONG THE FAR W END OF THE ITCZ. THE ITCZ LOOKS TO
REMAIN OVER THE AREA, WITH ENHANCED CONVECTION OCCURRING AS WEAK
TRADE-WIND TROUGHS MOVE ACROSS THE DATE LINE. THE TRADE-WIND TROUGH
WILL PULL THE W END OF THE ITCZ A LITTLE FARTHER W AS IT PROGRESSES.
KLEESCHULTE
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