890 
FXPQ60 PGUM 160844
AFDPQ 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
644 PM CHST THU APR 16 2015

.SYNOPSIS...
THE TRADE-WIND DISTURBANCE WHICH DUMPED MORE THAN TWO-THIRD OF AN
INCH OF RAIN ON GUAM HAS PULLED FARTHER WEST OF THE AREA. LATEST
ASCAT SATELLITE IMAGERY REVEALS A FRESH TRADE SURGE APPROACHING 155E.
TWO WEAK DISTURBANCES CAN BE SEEN EMBEDDED WITHIN THIS SURGE NEAR
160E AND 166E.

&&

.DISCUSSION...
WATER VAPOR SATELLITE LOOPS ALONG WITH GUAM SOUNDING DATA
INDICATE A VERY DRY AIR MASS ABOVE 600MB FROM 142E EASTWARD TO
164E. THIS AIR MASS ALONG WITH MODERATE TO FRESH TRADES WILL
PROVIDE A RELATIVELY DRY REGIME FOR THE MARIANA ISLANDS THROUGH
THIS WEEKEND. THE TWO DISTURBANCES UPSTREAM MIGHT PRODUCE SOME
CLOUDS AND A FEW SHALLOW SHOWERS FOR OUR ISLANDS SATURDAY AND
SUNDAY. A DISORGANIZED TROPICAL DISTURBANCE AND ITS ASSOCIATED
TROUGH ARE QUASI-STATIONARY OVER THE MARSHALL ISLANDS. MODEL
CONSENSUS IS STILL TRACKING THIS SYSTEM WEST-NORTHWESTWARD AND
BRINGING IT SOUTHEAST OF GUAM BY MONDAY NIGHT. PREVIOUS FORECAST
HAS ALREADY INTRODUCED CLOUDINESS FOR TUESDAY AND WEDNESDAY. IT IS
WAY TOO EARLY TO INCLUDE SCATTERED SHOWERS INTO THE FORECAST AT
THIS POINT.

&&

.MARINE...
BUILDING WIND WAVES AND SWELL GENERATED BY THE APPROACHING TRADE-
WIND SURGE WILL CAUSE SEAS AND SURF TO BUILD ACROSS THE MARIANA
ISLANDS THIS WEEKEND. HOWEVER SURF IS NOT EXPECTED TO REACH
HAZARDOUS LEVELS. SEAS SHOULD ALSO STAY BELOW SMALL CRAFT
ADVISORY HEIGHTS. BUT THERE IS A SLIGHT CHANCE THAT FREQUENT WIND
GUSTS OF SMALL CRAFT ADVISORY CRITERIA MIGHT OCCUR DURING THE
DAYTIME HOURS THIS WEEKEND.

&&

.EASTERN MICRONESIA...
UNSETTLED WEATHER REMAINS ACROSS EASTERN MICRONESIA. ASCAT ANALYSIS 
INDICATES A WEAK CIRCULATION NEAR 2N156E AND ANOTHER NEAR 3N169E. 
ALSO...A SHARP UPPER-LEVEL TROUGH BETWEEN WAKE AND KWAJALEIN IS 
HELPING TO TRIGGER NUMEROUS SHOWERS ACROSS CENTRAL AND NORTHEASTERN 
MARSHALL ISLANDS.

MAJURO...
MAJURO IS BETWEEN THE MOST SIGNIFICANT SHOWER ACTIVITY FARTHER NORTH 
AND FARTHER SOUTH AT THIS TIME...BUT A MOIST TRADE-WIND FLOW WITH A 
FEW SHOWERS AT TIMES WILL CONTINUE AT MAJURO THE NEXT DAY OR TWO. 
IMPROVING WEATHER IS STILL EXPECTED DURING THE WEEKEND.

KOSRAE...
MODERATE TRADE WINDS AND ISOLATED SHOWERS WILL CONTINUE FOR THE NEAR 
TERM...THEN MORE SHOWERY WEATHER WILL LIKELY ARRIVE FROM THE EAST BY 
THIS WEEKEND...WITH SLOWLY IMPROVING WEATHER NEXT WEEK.

POHNPEI AND CHUUK...
MODERATE TRADE WINDS AND VERY ISOLATED SHOWERS WILL PERSIST
THROUGH THE NEAR TERM. A TROPICAL DISTURBANCE CENTERED SOUTHWEST
OF POHNPEI NEAR 2N156E IS CAUSING SCATTERED SHOWERS ALONG AND
SOUTH OF 5N FROM 150E TO 160E. THIS DISTURBANCE IS EXPECTED TO
DRIFT WESTWARD AND SCATTERED SHOWERS SHOULD REMAIN SOUTH OF THE
POHNPEI AND WENO CHUUK AREAS THE NEXT FEW DAYS. LATER...CLOUDINESS
AND SOME SHOWERS COULD ARRIVE FROM THE EAST NEXT WEEK.

&&

.WESTERN MICRONESIA...
CHUUK DISCUSSION INCLUDED ABOVE WITH POHNPEI DUE TO SIMILAR WEATHER.

YAP AND KOROR...
SATELLITE SHOWS A FEW THUNDERSTORMS FAR WEST OF KOROR THIS AFTERNOON 
WHILE LIGHT TO MODERATE EASTERLY WINDS AND ISOLATED SHOWERS PREVAIL 
FOR BOTH KOROR AND YAP THIS AFTERNOON. THE MODEL SOLUTIONS DIFFER IN 
THE LONGER RANGE BUT GENERALLY INDICATE THAT A PATTERN OF LOW-LEVEL 
CONVERGENCE COULD SPREAD WESTWARD FROM THE DISTURBANCE SOUTH OF WENO 
CHUUK. NO BIG CHANGES WERE MADE TO THE FORECAST AT THIS TIME BUT 
LATER FORECASTS MAY NEED ADJUSTMENTS IF IT STARTS TO LOOK LIKE 
WETTER WEATHER COULD MOVE TOWARD THE KOROR AND YAP AREAS IN THE 
LONGER RANGE.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...NONE.
MARIANAS WATERS...NONE.

&&

$$

CHAN/SIMPSON