260
AXPQ20 PGUM 220109
TWDPQ
TROPICAL WEATHER DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
1109 AM CHST SAT FEB 22 2025
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
NONE.
..OTHER WEATHER SYSTEMS
TRADE-WIND TROUGHS...
THERE ARE FEW TRADE-WIND TROUGHS MOVING THROUGH THE REGION, WITH
SPOTTY TO SCATTERED SHOWERS DEVELOPING AROUND THESE TROUGHS. THE
FIRST IS LOCATED WELL SOUTH OF EASTERN YAP STATE FROM 4N144E TO
EQ147E AND IS SUPPORTING SOME SCATTERED SHOWERS ALONG THE TROUGH
AXIS. THIS TROUGH IS EXPECTED TO REMAIN CLOSE TO THE EQUATOR LIKELY
PASSING SOUTH OF THE MAIN ISLANDS OF YAP AND PALAU AS IT CONTINUES
WESTWARD.
THE FINAL PAIR OF TROUGHS ARE LOCATED NEAR EACH OTHER WITH THE FIRST
LOCATED BETWEEN POHNPEI AND KOSRAE FROM 8N161E TO 3N165E, AND THE
SECOND BETWEEN KOSRAE AND MAJURO FROM 6N165E TO 2N167E. THESE TROUGHS
ARE EMBEDDED WITH A LARGER AREA OF TRADE CONVERGENCE THAT EXTENDS
ALONG 5N FROM 160E TO THE DATE LINE, WITH SATELLITE SCATTEROMETER
DATA SHOWING WINDS OF 15 TO 25 KT NORTH OF 5N AND 5 TO 15 KT SOUTH OF
5N. THE COMBINATION OF THE TROUGHS AND TRADE CONVERGENCE IS CREATING
AN AREA OF SCATTERED SHOWERS FROM 160E TO 177E, BETWEEN 2N AND 7N.
THE GLOBAL LIGHTNING DETECTION (GLD) NETWORK HAS ONLY SHOWN A FEW
LIGHTNING STRIKES WELL EAST-SOUTHEAST OF KOSRAE OVER THE PAST 3
HOURS, WITH SOME OF THE SLIGHTLY HEAVIER SHOWERS, SUGGESTING
THUNDERSTORMS ARE ISOLATED AND SHORT-LIVED WITHIN THIS AREA OF
CONVECTION. THIS AREA OF CONVERGENCE AND TROUGHS ARE EXPECTED TO
CONTINUE WESTWARD PASSING SOUTH OF POHNPEI AND CHUUK LAGOON OVER THE
NEXT FEW DAYS, WITH MODELS SHOWING IT BEING ABSORBED BY THE NEAR-
EQUATORIAL TROUGH (NET) AS IT LIFTS NORTH OF THE EQUATOR, INCREASING
SHOWERS WELL SOUTH OF CHUUK LAGOON.
OTHER SYSTEMS...
A DECAYING COLD FRONT EXTENDS WEST-SOUTHWEST ACROSS 21N180 TO
SOUTHWEST OF WAKE ISLAND NEAR 16N160E. IT THEN CONTINUES WEST-
SOUTHWEST AS A SHEAR LINE TO END SOUTH OF PALAU NEAR 5N135E.
SATELLITE SCATTEROMETER SHOWS A LARGE AREA OF WINDS AROUND 20 KT
NORTH OF THE SHEAR LINE AND OVER THE MARIANAS FROM GUAM TO PAGAN,
WITH SMALLER POCKETS OF WINDS AROUND 20 KT NEAR YAP AND PALAU. THIS
IS CREATING BREEZY CONDITIONS ACROSS THE MARIANAS, YAP PROPER, AND
PALAU TODAY. EXTENSIVE CLOUDINESS WITH RAIN AND PATCHY SHOWERS IS
EVIDENT ON THE LATEST VISIBLE SATELLITE ALONG AND NORTH OF THE COLD
FRONT. CLOUDINESS WITH PATCHY LIGHT SHOWERS IS SEEN ALONG AND NORTH
OF THE SHEAR LINE, INCLUDING THE MARIANAS FROM GUAM TO SAIPAN AND
OVER YAP PROPER. ENHANCED CONVERGENCE ALONG THE SHEAR LINE NEAR PALAU
IS PRODUCING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THAT HAS
LIFTED UP INTO PALAU THIS MORNING. THE FRONT AND SHEAR LINE ARE
EXPECTED TO BECOME QUASI-STATIONARY, WITH THE FRONT CONTINUING TO
WEAKEN AND TRANSITIONING INTO A SHEAR LINE. THE SHEAR LINE MAY START
TO MOVE WEST-NORTHWEST OVER THE NEXT FEW DAYS AS IT IS PUSHED BY THE
TRADE-WIND FLOW, BEFORE BEING REPLACED BY A NEW SHEAR LINE THAT IS
EXPECTED TO MOVE INTO THE REGION NEXT WEEK. LATEST CIMMS MIMIC
PRECIPITABLE WATER PRODUCT SHOWS LIMITED MOISTURE ALONG AND JUST
NORTH OF THE SHEAR LINE, WITH MOST THE PWATS BELOW 1.8 INCHES NORTH
OF 10N. THEREFORE, CONVECTION LOOKS TO REMAIN LIMITED TO ONLY SHOWERS
THOUGH A THUNDERSTORM OR TWO IS NOT OUT OF THE QUESTION.
SCHANK
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