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000
FXPQ60 PGUM 242050
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
650 AM CHST SAT OCT 25 2014

.MARIANAS SYNOPSIS...
SCATTERED SHOWERS AND THUNDERSTORMS ASSOCIATED WITH AN UPPER LOW
CENTERED NW OF THE MARIANAS NEAR 20N143E ARE NOW WEST OF THE
ISLANDS AND MOVING WEST. RADAR SHOWS ISOLATED SHOWERS AND
THUNDERSTORMS NEAR AND EAST OF THE ISLANDS...MAINLY UP NEAR SAIPAN
AND TINIAN.

&&

.DISCUSSION...
GFS...ECMWF AND NAVGEM DISAGREE ON SOME DETAILS...BUT ALL THREE
MODELS KEEP THE MARIANAS IN AN UNSETTLED EASTERLY FLOW NORTH OF
WEAK AND ILL-DEFINED TROUGHING TO THE SOUTH FOR SOME TIME. ALL THE
MODELS NOW BRING IN A FAIR AMOUNT OF MOISTURE OVER THE NEXT WEEK
OR MORE WITH POTENTIAL FOR SCATTERED SHOWERS AT TIMES IN THE NEXT
10 DAYS. THE ECMWF IS MOST GENEROUS WITH 0VER 5 INCHES...AND IT
SETS UP THE BEST-ORGANIZED MONSOON PATTERN OF ANY OF THE MODELS.
HAVE EXTENDED MOSTLY CLOUDY WITH ISOLATED SHOWERS AND
THUNDERSTORMS THROUGH AT LEAST WEDNESDAY NIGHT...AND WILL HAVE TO
WATCH OUT FOR THE POSSIBILITY OF MORE THAN ISOLATED AT TIMES.

&&

.MARINE/SURF...
WW3 GUIDANCE FOR SEAS AND SWELL SEEMS A LITTLE ON THE LOW SIDE
COMPARED WITH BUOY OBSERVATIONS...AND HAVE BOOSTED WAVE GRIDS A
FOOT FOR TODAY THROUGH SUNDAY. BUOY SWELL SPECTRA SHOW THAT THE
LONG-PERIOD NORTHEAST SWELL IS FAR AND AWAY THE DOMINANT COMPONENT
AND SHOULD KEEP HIGH SURF GOING THROUGH SUNDAY AFTERNOON ON NORTH-
FACING REEFS. THE SWELL WILL DIMINISH SUNDAY NIGHT AND MONDAY
WITH A MODERATE RIP RISK FOR MOST OF NEXT WEEK.

&&

.EASTERN MICRONESIA...
THE SURFACE TROUGH MOVING WESTWARD FROM THE MARSHALL ISLANDS HAS
MERGED WITH THE CIRCULATION SOUTH OF POHNPEI NEAR 5N158E. THIS
COMBINED SYSTEM WILL KEEP SHOWERS AND A FEW THUNDERSTORMS NEAR
POHNPEI TODAY. AS THEY SLOWLY DRIFT WESTWARD AWAY FROM POHNPEI
THIS EVENING...THIS WILL LET WEAKER SOUTHEASTERLY TRADES ALREADY
OVER KOSRAE REACH POHNPEI. HOWEVER THESE MODEST CONVERGING
SOUTHEAST WINDS CAN STILL TRIGGER ISOLATED CONVECTION NEAR BOTH
POHNPEI AND KOSRAE THRU SUNDAY. FARTHER EAST...A TRADE-WIND
CONVERGENCE ZONE CAN BE SEEN BETWEEN 4N AND 8N STRETCHING EASTWARD
FROM NEAR MAJURO THRU THE DATE LINE TO A TRADE DISTURBANCE NEAR
165W. SPORADIC DEEP CONVECTION ASSOCIATED WITH THE ZONE AND
DISTURBANCE WILL AFFECT MAJURO THRU MONDAY. WITH THESE FEATURES
PUSHING FARTHER WESTWARD INTO THE REGION OVER THE NEXT COUPLE OF
DAYS...INCLEMENT WEATHER WILL ALSO IMPACT KOSRAE AND POHNPEI BY
MONDAY. THINGS FINALLY IMPROVE TOWARD MIDWEEK NEXT WEEK WHEN GENTLE
TRADES RETURN TO THE REGION FROM EAST TO WEST.

LONG-PERIOD NORTH-NORTHEAST SWELL WILL MAINTAIN HAZARDOUS SURF
ACROSS CHUUK AND POHNPEI STATES UNTIL SUNDAY AFTERNOON. LATEST
READINGS FROM THE KALO BUOY AT MAJURO INDICATE THESE SWELLS HAVE
ARRIVED AT THE MARSHALL ISLANDS. BLOCKAGE CAUSED BY THE NORTHERN
MARSHALL ISLANDS HAS REDUCED THE SWELLS TO BETWEEN 3 AND 4 FEET
WITH A PERIOD OF NEAR 11 SECONDS...RESULTING IN SURF HEIGHTS OF 5
TO 6 FEET. COUPLED WITH SPRING HIGH TIDES OF 4 TO 5 FEET AT MAJURO
ATOLL...THE CRITERION FOR COASTAL INUNDATION WILL PROBABLY NOT BE
MET...BUT IT WILL BE CLOSE. WHILE NO INUNDATION IS EXPECTED...THE
RISK OF RIP CURRENTS WILL BE HIGHER DURING HIGH TIDES FROM THIS
AFTERNOON TO MONDAY AFTERNOON. DAY SHIFT MIGHT WANT TO INCLUDE A
HEADLINE MENTIONING THIS IN THE MAJURO FORECAST.

&&

.WESTERN MICRONESIA...
THE CIRCULATION AND ITS RELATED TROUGH NEAR POHNPEI THIS MORNING
WILL APPROACH CHUUK THIS AFTERNOON AND TONIGHT. THEREFORE...EXPECT
INCREASING SHOWERS OVER CHUUK BY THIS EVENING. AFTER THE PASSAGE
OF THESE FEATURES ON SUNDAY NIGHT...WEAK RIDGING FOLLOWING BEHIND
SHOULD USHER IN A QUIETER PERIOD. THEN BY EARLY NEXT WEEK...THE
TRADE CONVERGENCE ZONE CURRENTLY AFFECTING MAJURO SHOULD ARRIVE AT
CHUUK WITH MORE WET WEATHER. REFER TO THE SECOND PARAGRAPH UNDER
THE EASTERN MICRONESIA DISCUSSION ABOVE FOR HAZARDOUS SURF
CONDITIONS THRU SUNDAY MORNING.

THE WEAK MONSOON TROUGH NEAR KOROR AND YAP IS GRADUALLY LIFTING
NORTHWARD THIS MORNING. THIS WILL ALLOW THE THREAT OF THUNDERSTORMS
TO DECREASE ACROSS BOTH LOCATIONS BY TONIGHT. ONCE THE TROUGH AXIS
HAS MOVED FARTHER NORTH INTO THE PHILIPPINE SEA ON SUNDAY...LIGHT
WINDS TO THE SOUTH WILL PROMOTE PARTLY CLOUDY SKIES FOR THE AREA
THRU MONDAY. TOWARD MIDWEEK...THE CHANCE OF SHOWERS WILL INCREASE AS
THE CIRCULATION CURRENTLY NEAR POHNPEI MAKES ITS WAY WESTWARD.
REMNANTS OF THE NORTH-NORTHEAST SWELLS AFFECTING THE MARIANA ISLANDS
ARE SCHEDULED TO ARRIVE AT YAP STATE AND PALAU TONIGHT. SURF HEIGHTS
SHOULD STAY BELOW ADVISORY LEVELS BUT THE RISK OF RIP CURRENTS WILL
BE HIGHER.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF ADVISORY UNTIL 4 PM CHST SUNDAY FOR GUZ001>004.

MARIANAS WATERS...NONE.
&&

$$

MIDDLEBROOKE/CHAN







000
FXPQ60 PGUM 240815 AAA
AFDPQ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TIYAN GU
615 PM CHST FRI OCT 24 2014

UPDATED TO INCLUDE DISCUSSIONS FOR EASTERN AND WESTERN MICRONESIA

.MARIANAS SYNOPSIS...
RELATIVELY WEAK LOW-LEVEL FLOW PATTERN CONTINUES OVER THE
FORECAST ZONES. MONSOON TROUGH PASSES SOUTH OF GUAM NEAR 11N.
TUTT STRETCHES FROM EAST TO WEST NEAR THE FAR NORTHERN CNMI ALONG
20N. CONVERGENT EAST TO SOUTHEAST WINDS ARE PRODUCING A FEW CBS
EAST OF TINIAN AND SAIPAN. 00Z SOUNDING CARRIED A PWAT OF 2
INCHES. THIS...COMBINED WITH THE LIGHT WIND REGIME...HAS ALLOWED
AFTERNOON THUNDERSTORMS TO FORM JUST TO THE NORTHWEST OF GUAM.

&&

.DISCUSSION...
ONLY SIGNIFICANT UPDATE TO THE FORECAST GRIDS WAS TO ADD ISOLATED
THUNDER THROUGH SATURDAY NIGHT. AFTER THEN...DEPTH OF LOW-LEVEL
MOISTURE SHOULD BE SHALLOW ENOUGH TO INHIBIT DEEP CONVECTION.
FORECAST CONTINUES TO FOLLOW A DRY BIAS VERSUS THE ECMWF AND
GFS40. GFS 40 APPEARS TO SUFFER FROM CONVECTIVE FEEDBACK DURING
MUCH OF NEXT WEEK AND SPINS UP SEVERAL WEAK CIRCULATIONS NEAR AND
EAST OF THE MARIANAS...WHILE THE ECMWF SEEMS TO BE TOO AGGRESSIVE
IN DEVELOPING CIRCULATIONS IN THE MONSOON TROUGH SOUTH OF GUAM.
LATEST NAVGEM RUN SUGGESTS ATMOSPHERE MAY BE MOISTER THAN EARLIER
ANTICIPATED DURING THE UPCOMING WEEK. WILL WAIT FOR SATELLITE
TRENDS TO CONFIRM A WETTER PATTERN BEFORE MAKING CHANGES TO POPS
OR CLOUD COVER. HAVE KEPT TRADE WINDS IN THE GRIDS FOR DAYS 9 AND
10. BOTH ECMWF AND GFS 40 DEVELOP A CIRCULATION EAST OF THE
FORECAST DOMAIN ON DAYS 9 AND 10.

&&

.MARINE...
MARINE SWELL GRIDS WERE INC GOOD SHAPE AND REQUIRED ONLY A FEW
COSMETIC CHANGES. BUOYS AND LATEST ALTIMETRY INITIALIZE PRIMARY
NORTHEAST SWELL BETWEEN 5 AND 6 FT FROM 045 DEGREES WITH A PERIOD
OF 13 SECONDS. STILL EXPECT MINIMAL HIGH SURF EVENT ON NORTH
FACING REEFS TONIGHT THROUGH SUNDAY.

&&

.EASTERN MICRONESIA...
THREE WEATHER FEATURES CAN BE SEEN ACROSS THE REGION THIS
AFTERNOON...A CIRCULATION SOUTHEAST OF POHNPEI...A SURFACE TROUGH
RUNNING NORTHEASTWARD FROM THE CIRCULATION...AND CONVERGENT EAST
WINDS EAST OF MAJURO. EXTENSIVE CLOUD COVER...SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS ARE ASSOCIATED WITH EACH OF THESE FEATURES.
THE CIRCULATION IS GOING TO PASS SOUTH OF POHNPEI TONIGHT. THIS
SHOULD ALLOW THE BULK OF THE INITIAL CONVECTION TO PASS TO THE SOUTH
OF POHNPEI TONIGHT AND SATURDAY. CONVECTION ASSOCIATED WITH THE
SURFACE TROUGH SHOULD REACH POHNPEI SATURDAY NIGHT. KOSRAE IS IN
LINE WITH THE CONVECTION FROM THE CIRCULATION AND TROUGH TONIGHT AND
SATURDAY. MAJURO IS LOCATED IN A WEAK RIDGE THIS EVENING...BUT
CONVERGENT SOUTHEAST AND EAST WINDS FOLLOW LATER TONIGHT. THE WEAK
SURFACE RIDGING EAST OF THE TROUGH COULD PROVIDE DRYER WEATHER FOR
MAJURO FOR THIS WEEKEND...AND KOSRAE AND POHNPEI EARLY NEXT WEEK.
AFTERWARD A TRADE-WIND CONVERGENCE ZONE CURRENTLY UPSTREAM EAST OF
THE DATE LINE MIGHT BRING MORE INSTABILITY FOR THE REGION LATER NEXT
WEEK.

LONG-PERIOD NORTH-NORTHEAST SWELLS PRODUCED BY A STRONG LOW PRESSURE
SYSTEM CURRENTLY NEAR 36N176E ARRIVED AT CHUUK AND POHNPEI
STATES TODAY. THIS WILL CAUSE HAZARDOUS SURF CONDITIONS FOR BOTH
PLACES BY TONIGHT AND SHOULD LAST UNTIL SUNDAY AFTERNOON.
HOWEVER...LATEST ASCAT IMAGERY DOES NOT INDICATE STRONG WINDS AND A
FETCH DIRECTED AT MAJURO AND KOSRAE.

&&

.WESTERN MICRONESIA...
ANOTHER SURFACE TROUGH NEAR CHUUK IS BRINGING SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS TO CHUUK TONIGHT. THIS TROUGH IS CURRENTLY
INTERACTING WITH ANOTHER SURFACE TROUGH TO THE NORTHEAST. AS THESE
TWO TROUGHS SEPARATE...THE HEAVY RAIN WENO ISLAND RECEIVED FRIDAY
AFTERNOON WILL LESSEN IN INTENSITY. ONCE THIS CIRCULATION AND TROUGH
HAVE PULLED WEST OF CHUUK ON SATURDAY NIGHT...A BRIEF IMPROVEMENT IS
POSSIBLE. HOWEVER WEATHER WILL WORSEN AGAIN ON SUNDAY AS THE TRADE
DISTURBANCE CURRENTLY OVER THE MARSHALL ISLANDS ARRIVES. AFTER THE
PASSAGE OF THIS DISTURBANCE...THINGS COULD FINALLY QUIET DOWN FOR
EARLY NEXT WEEK. REFER TO THE SECOND PARAGRAPH UNDER THE EASTERN
MICRONESIA DISCUSSION ABOVE FOR HAZARDOUS SURF CONDITIONS TONIGHT
AND SATURDAY.

ANTICIPATE A WEAK MONSOON TROUGH TO LINGER NEAR KOROR AND YAP THRU
SATURDAY. THIS TROUGH WILL COINCIDE WITH MODEST DIVERGENT FLOW ALONG
THE WESTERN HALF OF AN UPPER HIGH NEAR 7N143E...CAUSING A SLIGHT
THREAT OF THUNDERSTORMS FOR BOTH LOCALES. WITH THIS TROUGH EXPECTED
TO LIFT NORTHWESTWARD INTO THE PHILIPPINE SEA SATURDAY NIGHT AND
SUNDAY...FAIR WEATHER AND GENTLE WINDS SHOULD RETURN TO THE AREA.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF ADVISORY UNTIL 4 PM CHST SUNDAY FOR GUZ001>004.

MARIANAS WATERS...NONE.
&&

$$

MCELROY/DEVITA








000
FXPQ60 PGUM 240815 AAA
AFDPQ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TIYAN GU
615 PM CHST FRI OCT 24 2014

UPDATED TO INCLUDE DISCUSSIONS FOR EASTERN AND WESTERN MICRONESIA

.MARIANAS SYNOPSIS...
RELATIVELY WEAK LOW-LEVEL FLOW PATTERN CONTINUES OVER THE
FORECAST ZONES. MONSOON TROUGH PASSES SOUTH OF GUAM NEAR 11N.
TUTT STRETCHES FROM EAST TO WEST NEAR THE FAR NORTHERN CNMI ALONG
20N. CONVERGENT EAST TO SOUTHEAST WINDS ARE PRODUCING A FEW CBS
EAST OF TINIAN AND SAIPAN. 00Z SOUNDING CARRIED A PWAT OF 2
INCHES. THIS...COMBINED WITH THE LIGHT WIND REGIME...HAS ALLOWED
AFTERNOON THUNDERSTORMS TO FORM JUST TO THE NORTHWEST OF GUAM.

&&

.DISCUSSION...
ONLY SIGNIFICANT UPDATE TO THE FORECAST GRIDS WAS TO ADD ISOLATED
THUNDER THROUGH SATURDAY NIGHT. AFTER THEN...DEPTH OF LOW-LEVEL
MOISTURE SHOULD BE SHALLOW ENOUGH TO INHIBIT DEEP CONVECTION.
FORECAST CONTINUES TO FOLLOW A DRY BIAS VERSUS THE ECMWF AND
GFS40. GFS 40 APPEARS TO SUFFER FROM CONVECTIVE FEEDBACK DURING
MUCH OF NEXT WEEK AND SPINS UP SEVERAL WEAK CIRCULATIONS NEAR AND
EAST OF THE MARIANAS...WHILE THE ECMWF SEEMS TO BE TOO AGGRESSIVE
IN DEVELOPING CIRCULATIONS IN THE MONSOON TROUGH SOUTH OF GUAM.
LATEST NAVGEM RUN SUGGESTS ATMOSPHERE MAY BE MOISTER THAN EARLIER
ANTICIPATED DURING THE UPCOMING WEEK. WILL WAIT FOR SATELLITE
TRENDS TO CONFIRM A WETTER PATTERN BEFORE MAKING CHANGES TO POPS
OR CLOUD COVER. HAVE KEPT TRADE WINDS IN THE GRIDS FOR DAYS 9 AND
10. BOTH ECMWF AND GFS 40 DEVELOP A CIRCULATION EAST OF THE
FORECAST DOMAIN ON DAYS 9 AND 10.

&&

.MARINE...
MARINE SWELL GRIDS WERE INC GOOD SHAPE AND REQUIRED ONLY A FEW
COSMETIC CHANGES. BUOYS AND LATEST ALTIMETRY INITIALIZE PRIMARY
NORTHEAST SWELL BETWEEN 5 AND 6 FT FROM 045 DEGREES WITH A PERIOD
OF 13 SECONDS. STILL EXPECT MINIMAL HIGH SURF EVENT ON NORTH
FACING REEFS TONIGHT THROUGH SUNDAY.

&&

.EASTERN MICRONESIA...
THREE WEATHER FEATURES CAN BE SEEN ACROSS THE REGION THIS
AFTERNOON...A CIRCULATION SOUTHEAST OF POHNPEI...A SURFACE TROUGH
RUNNING NORTHEASTWARD FROM THE CIRCULATION...AND CONVERGENT EAST
WINDS EAST OF MAJURO. EXTENSIVE CLOUD COVER...SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS ARE ASSOCIATED WITH EACH OF THESE FEATURES.
THE CIRCULATION IS GOING TO PASS SOUTH OF POHNPEI TONIGHT. THIS
SHOULD ALLOW THE BULK OF THE INITIAL CONVECTION TO PASS TO THE SOUTH
OF POHNPEI TONIGHT AND SATURDAY. CONVECTION ASSOCIATED WITH THE
SURFACE TROUGH SHOULD REACH POHNPEI SATURDAY NIGHT. KOSRAE IS IN
LINE WITH THE CONVECTION FROM THE CIRCULATION AND TROUGH TONIGHT AND
SATURDAY. MAJURO IS LOCATED IN A WEAK RIDGE THIS EVENING...BUT
CONVERGENT SOUTHEAST AND EAST WINDS FOLLOW LATER TONIGHT. THE WEAK
SURFACE RIDGING EAST OF THE TROUGH COULD PROVIDE DRYER WEATHER FOR
MAJURO FOR THIS WEEKEND...AND KOSRAE AND POHNPEI EARLY NEXT WEEK.
AFTERWARD A TRADE-WIND CONVERGENCE ZONE CURRENTLY UPSTREAM EAST OF
THE DATE LINE MIGHT BRING MORE INSTABILITY FOR THE REGION LATER NEXT
WEEK.

LONG-PERIOD NORTH-NORTHEAST SWELLS PRODUCED BY A STRONG LOW PRESSURE
SYSTEM CURRENTLY NEAR 36N176E ARRIVED AT CHUUK AND POHNPEI
STATES TODAY. THIS WILL CAUSE HAZARDOUS SURF CONDITIONS FOR BOTH
PLACES BY TONIGHT AND SHOULD LAST UNTIL SUNDAY AFTERNOON.
HOWEVER...LATEST ASCAT IMAGERY DOES NOT INDICATE STRONG WINDS AND A
FETCH DIRECTED AT MAJURO AND KOSRAE.

&&

.WESTERN MICRONESIA...
ANOTHER SURFACE TROUGH NEAR CHUUK IS BRINGING SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS TO CHUUK TONIGHT. THIS TROUGH IS CURRENTLY
INTERACTING WITH ANOTHER SURFACE TROUGH TO THE NORTHEAST. AS THESE
TWO TROUGHS SEPARATE...THE HEAVY RAIN WENO ISLAND RECEIVED FRIDAY
AFTERNOON WILL LESSEN IN INTENSITY. ONCE THIS CIRCULATION AND TROUGH
HAVE PULLED WEST OF CHUUK ON SATURDAY NIGHT...A BRIEF IMPROVEMENT IS
POSSIBLE. HOWEVER WEATHER WILL WORSEN AGAIN ON SUNDAY AS THE TRADE
DISTURBANCE CURRENTLY OVER THE MARSHALL ISLANDS ARRIVES. AFTER THE
PASSAGE OF THIS DISTURBANCE...THINGS COULD FINALLY QUIET DOWN FOR
EARLY NEXT WEEK. REFER TO THE SECOND PARAGRAPH UNDER THE EASTERN
MICRONESIA DISCUSSION ABOVE FOR HAZARDOUS SURF CONDITIONS TONIGHT
AND SATURDAY.

ANTICIPATE A WEAK MONSOON TROUGH TO LINGER NEAR KOROR AND YAP THRU
SATURDAY. THIS TROUGH WILL COINCIDE WITH MODEST DIVERGENT FLOW ALONG
THE WESTERN HALF OF AN UPPER HIGH NEAR 7N143E...CAUSING A SLIGHT
THREAT OF THUNDERSTORMS FOR BOTH LOCALES. WITH THIS TROUGH EXPECTED
TO LIFT NORTHWESTWARD INTO THE PHILIPPINE SEA SATURDAY NIGHT AND
SUNDAY...FAIR WEATHER AND GENTLE WINDS SHOULD RETURN TO THE AREA.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF ADVISORY UNTIL 4 PM CHST SUNDAY FOR GUZ001>004.

MARIANAS WATERS...NONE.
&&

$$

MCELROY/DEVITA








000
FXPQ60 PGUM 240615
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
415 PM CHST FRI OCT 24 2014

.MARIANAS SYNOPSIS...
RELATIVELY WEAK LOW-LEVEL FLOW PATTERN CONTINUES OVER THE
FORECAST ZONES. MONSOON TROUGH PASSES SOUTH OF GUAM NEAR 11N.
TUTT STRETCHES FROM EAST TO WEST NEAR THE FAR NORTHERN CNMI ALONG
20N. CONVERGENT EAST TO SOUTHEAST WINDS ARE PRODUCING A FEW CBS
EAST OF TINIAN AND SAIPAN. 00Z SOUNDING CARRIED A PWAT OF 2
INCHES. THIS...COMBINED WITH THE LIGHT WIND REGIME...HAS ALLOWED
AFTERNOON THUNDERSTORMS TO FORM JUST TO THE NORTHWEST OF GUAM.

&&

.DISCUSSION...
ONLY SIGNIFICANT UPDATE TO THE FORECAST GRIDS WAS TO ADD ISOLATED
THUNDER THROUGH SATURDAY NIGHT. AFTER THEN...DEPTH OF LOW-LEVEL
MOISTURE SHOULD BE SHALLOW ENOUGH TO INHIBIT DEEP CONVECTION.
FORECAST CONTINUES TO FOLLOW A DRY BIAS VERSUS THE ECMWF AND
GFS40. GFS 40 APPEARS TO SUFFER FROM CONVECTIVE FEEDBACK DURING
MUCH OF NEXT WEEK AND SPINS UP SEVERAL WEAK CIRCULATIONS NEAR AND
EAST OF THE MARIANAS...WHILE THE ECMWF SEEMS TO BE TOO AGGRESSIVE
IN DEVELOPING CIRCULATIONS IN THE MONSOON TROUGH SOUTH OF GUAM.
LATEST NAVGEM RUN SUGGESTS ATMOSPHERE MAY BE MOISTER THAN EARLIER
ANTICIPATED DURING THE UPCOMING WEEK. WILL WAIT FOR SATELLITE
TRENDS TO CONFIRM A WETTER PATTERN BEFORE MAKING CHANGES TO POPS
OR CLOUD COVER. HAVE KEPT TRADE WINDS IN THE GRIDS FOR DAYS 9 AND
10. BOTH ECMWF AND GFS 40 DEVELOP A CIRCULATION EAST OF THE
FORECAST DOMAIN ON DAYS 9 AND 10.

&&

.MARINE...
MARINE SWELL GRIDS WERE INC GOOD SHAPE AND REQUIRED ONLY A FEW
COSMETIC CHANGES. BUOYS AND LATEST ALTIMETRY INITIALIZE PRIMARY
NORTHEAST SWELL BETWEEN 5 AND 6 FT FROM 045 DEGREES WITH A PERIOD
OF 13 SECONDS. STILL EXPECT MINIMAL HIGH SURF EVENT ON NORTH
FACING REEFS TONIGHT THROUGH SUNDAY.

&&

.EASTERN MICRONESIA...WILL BE ADDED LATER.


&&

.WESTERN MICRONESIA...WILL BE ADDED LATER.


&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF ADVISORY UNTIL 4 PM CHST SUNDAY FOR GUZ001>004.

MARIANAS WATERS...NONE.
&&

$$

MCELROY/DEVITA







000
FXPQ60 PGUM 232012
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
612 AM CHST FRI OCT 24 2014

.MARIANAS SYNOPSIS...
THE TROUGH THAT SPARKED ALL THE THUNDERSTORMS THURSDAY EVENING HAS
MOVED ON TO THE NORTHWEST OF THE ISLANDS. RADAR SHOWS ISOLATED
BRIEF THUNDERSTORMS STILL LINGERING WEST OF SAIPAN...BUT THESE ARE
EXPECTED TO CLEAR THE MARINE ZONES BY DAYBREAK.

&&

.DISCUSSION...
LITTLE CHANGE WAS NEEDED TO THE FORECAST...WITH SOME MINOR
ADJUSTMENTS TO THE WINDS BEHIND THE DEPARTING TROUGH. LINGERING
MOISTURE WILL KEEP SKIES MOSTLY CLOUDY THROUGH SATURDAY NIGHT BUT
LACK OF DYNAMIC SUPPORT SHOULD KEEP THUNDERSTORMS AT A MINIMUM. A
TRADE-WIND PATTERN OF GENTLE EAST WINDS AND ISOLATED SHOWERS
SHOULD LAST WELL INTO NEXT WEEK.

&&

.MARINE/SURF...
STILL LOOKING FOR A RENEWED SURGE OF NORTHEAST SWELL AND HIGH SURF
ALONG NORTH FACING REEFS THROUGH SUNDAY...THOUGH IT WILL BE
MARGINAL. THE HIGH SURF AND SWELL SHOULD DECLINE SUNDAY EVENING...
AND THE REST OF NEXT WEEK SHOULD FEATURE SEAS FALLING BACK TO 3 TO
4 FEET.

&&

.EASTERN MICRONESIA...
TWO MAJOR WEATHER FEATURES ARE SEEN ACROSS THE REGION THIS
MORNING...A CIRCULATION JUST SOUTHEAST OF POHNPEI AND A TRADE-WIND
DISTURBANCE OVER THE MARSHALL ISLANDS. THE CIRCULATION IS GOING TO
PASS SOUTH OF POHNPEI TONIGHT...ALLOWING CONVECTION TO DECREASE
OVER POHNPEI THIS EVENING. THE AXIS OF THE TRADE DISTURBANCE WILL
MOVE THRU THE WESTERN MARSHALL ISLANDS TODAY. SURFACE CONVERGENCE
AHEAD OF THIS DISTURBANCE IS ALREADY GENERATING SHOWERS AND A FEW
THUNDERSTORMS NEAR KOSRAE AND THIS TREND WILL CONTINUE UNTIL THIS
EVENING. CONVERGING SOUTHEAST WINDS EAST OF THE DEPARTING
DISTURBANCE WILL ALSO TRIGGER PERIODIC CONVECTION NEAR MAJURO THIS
AFTERNOON AND EVENING. AS THIS DISTURBANCE GRADUALLY PROGRESSES
WESTWARD...IT WILL AFFECT KOSRAE ON SATURDAY AND POHNPEI SATURDAY
NIGHT. WEAK SURFACE RIDGING EAST OF THE DISTURBANCE COULD PROVIDE
DRIER WEATHER FOR MAJURO FOR THIS WEEKEND...KOSRAE AND POHNPEI
EARLY NEXT WEEK. AFTERWARD A TRADE-WIND CONVERGENCE ZONE CURRENTLY
UPSTREAM EAST OF THE DATE LINE MIGHT BRING MORE INSTABILITY FOR
THE REGION LATER NEXT WEEK.

LONG-PERIOD NORTH-NORTHEAST SWELLS PRODUCED BY A STRONG LOW PRESSURE
SYSTEM CURRENTLY NEAR 35N175E WILL ARRIVE IN CHUUK AND POHNPEI
STATES TODAY. THIS WILL CAUSE HAZARDOUS SURF FOR BOTH PLACES BY
TONIGHT AND SHOULD LAST UNTIL SUNDAY AFTERNOON. BASED ON THE LATEST
SATELLITE ALTIMETRY DATA...THESE SAME NORTH-NORTHEAST SWELLS ARE ALSO
APPROACHING ENEWETAK AND RONGELAP ATOLLS NORTHWEST OF KWAJALEIN ATOLL
IN THE MARSHALL ISLANDS. AS THE LOW PRESSURE SYSTEM DRIFTS
NORTHEASTWARD ACROSS THE DATE LINE ON SATURDAY...THESE SWELLS
SHOULD CONTINUE TO SPREAD SOUTHEASTWARD TOWARD MAJURO. HOWEVER THE
WW3 MODEL IS DAMPING OUT MOST OF THESE SWELLS ARRIVING AT MAJURO ON
SATURDAY. THIS SEEMS TO BE OVERDONE AND NEEDS TO BE CLOSELY WATCHED.
IF SWELLS TURN OUT TO BE LARGER THAN MODEL GUIDANCE...THEY COULD
COMBINE WITH ONGOING SPRING HIGH TIDES TO CAUSE COASTAL INUNDATION
THRU MONDAY.

&&

.WESTERN MICRONESIA...
CHUUK WILL HAVE PARTLY SUNNY SKIES TODAY BEFORE WET WEATHER FROM
THE CIRCULATION APPROACHING FROM NEAR POHNPEI REACHES WENO ISLAND
THIS EVENING. ONCE THIS CIRCULATION HAS PULLED WEST OF CHUUK ON
SATURDAY NIGHT...A BRIEF IMPROVEMENT IS POSSIBLE. HOWEVER WEATHER
WILL WORSEN AGAIN ON SUNDAY AS THE TRADE DISTURBANCE CURRENTLY
OVER THE MARSHALL ISLANDS ARRIVES. AFTER THE PASSAGE OF THIS
DISTURBANCE...THINGS WILL FINALLY QUIET DOWN FOR EARLY NEXT WEEK.
REFER TO THE SECOND PARAGRAPH UNDER THE EASTERN MICRONESIA
DISCUSSION ABOVE FOR HAZARDOUS SURF CONDITIONS TONIGHT AND
SATURDAY.

A WEAK MONSOON TROUGH IS EXPECTED TO LINGER NEAR KOROR AND YAP
THRU SATURDAY. WITH MODEST DIVERGENT FLOW ALONG THE WESTERN HALF
OF AN UPPER HIGH NEAR 7N143E...A SLIGHT THREAT OF THUNDERSTORMS IS
EXPECTED FOR BOTH LOCALES. WITH THIS TROUGH EXPECTED TO LIFT
NORTHWESTWARD INTO THE PHILIPPINE SEA SATURDAY NIGHT AND
SUNDAY...FAIR WEATHER AND GENTLE WINDS SHOULD RETURN TO THE AREA.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF ADVISORY UNTIL 4 PM CHST SUNDAY FOR GUZ001>004.

MARIANAS WATERS...NONE.
&&

$$

MIDDLEBROOKE/CHAN







000
FXPQ60 PGUM 231045
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
845 PM CHST THU OCT 23 2014

.UPDATE...
TROUGH TO THE NORTHWEST WAS EXPECTED TO INTERACT WITH THE TROUGH
TO THE SOUTHEAST. THIS WOULD HAVE CAUSED THE TROUGH TO THE
SOUTHEAST TO MOVE FARTHER NORTH...THEREFORE EXPECTED TO AFFECT
PRIMARILY TINIAN AND SAIPAN. THIS INTERACTION EITHER DID NOT OCCUR
OR WAS WEAKER THAN EXPECTED. THIS PLACED BETTER WEATHER OVER
TINIAN AND SAIPAN WITH THE MORE ACTIVE WEATHER AFFECTING GUAM AND
ROTA.

&&

.PREV DISCUSSION... /ISSUED 513 PM CHST THU OCT 23 2014/

MARIANAS SYNOPSIS...
A WEAK CIRCULATION IS CENTERED JUST SOUTHEAST OF GUAM NEAR 12.5N
AND 145.5E. SCATTERED SHOWERS OVER GUAM AND ROTA THIS MORNING
THIS MORNING DISSIPATED RAPIDLY BEFORE NOON. RADAR AND SATELLITE
IMAGERY SHOW MORE SHOWERS DEVELOPING ON THE DOWN SHEAR SIDE OF
THE CIRCULATION OVER THE COASTAL WATERS EAST OF GUAM. MOST OF THE
SHOWERS APPEAR TO BE CONCENTRATED ON THE EAST SIDE OF THE
CIRCULATION BETWEEN 10N AND 15N FROM 148E TO 150E.

DISCUSSION...
THE WEAK CIRCULATION JUST EAST OF GUAM IS EMBEDDED WITHIN THE
MONSOON TROUGH AND IS EXPECTED TO PASS OVER GUAM TONIGHT. FELT
GFS INITIALIZED WELL IN TERMS OF SPATIAL CHARACTERISTICS OF
CONVECTION THIS MORNING. GFS AND HIGHER RESOLUTION MODELS
INDICATE THAT MUCH OF THE SHOWER ACTIVITY ASSOCIATED WITH THE
SYSTEM WILL DEVELOP TO THE NORTH OF THE CIRCULATION CENTER OVER
TINIAN AND SAIPAN LATER TONIGHT SO OPTED FOR SCATTERED WORDING
LATE TONIGHT. THIS CORROBORATES WELL WITH CURRENT SATELLITE
IMAGERY SHOWING SHOWER ACTIVITY INCREASING EAST AND NORTH OF THE
CIRCULATION. UPPER-LEVEL DYNAMICS ARE NOT IDEAL FOR THUNDERSTORM
DEVELOPMENT BUT CANNOT RULE OUT A THUNDERSTORM OR TWO OVERNIGHT
NORTH OF ROTA. IN THE LONG TERM...GFS AND NAVGEM ARE STILL THE
DRIER SOLUTIONS COMPARED TO THE ECMWF. ECMWF INCREASES MOISTURE
AND SHOWERS AND DEVELOPS A BROAD CIRCULATION SOUTH OF THE
MARIANAS MORE AGGRESSIVELY THAN THE GFS AND NAVGEM OVER THE
WEEKEND. UNCERTAINTY STILL EXISTS REGARDING SHOWER COVERAGE
DURING THE 3 TO 5-DAY TIME FRAME BUT MAINTAINED THE DRIER
SCENARIO UNTIL MODELS COME INTO MORE OF A CONSENSUS DURING THE
NEXT SEVERAL RUNS.

MARINE...
TANAPAG AND RITIDIAN BUOYS SHOW N-NE SWELL CONTINUING TO SLOWLY
DIMINISH ACROSS THE MARIANAS. A SECOND...LONG-PERIOD NORTHEAST
SWELL EVENT WILL COMMENCE FRIDAY BEGINNING WITH SAIPAN. THIS WILL
CAUSE SURF TO RISE TO HAZARDOUS LEVELS FRIDAY AFTER A BRIEF DROP
IN SURF HEIGHTS TONIGHT. SURF HEIGHTS OF 7 TO 9 FEET ARE EXPECTED
THROUGH MUCH OF THE WEEKEND WITH SURF EXPECTED TO DROP BELOW
HAZARDOUS LEVELS SUNDAY AFTERNOON.

EASTERN MICRONESIA...
AN INVERTED SURFACE TROUGH IS APPROACHING MAJURO FROM THE EAST.
UPDATED MAJURO FORECAST THIS MORNING TO INCREASE SHOWER COVERAGE
TO SCATTERED...BUT CONVECTION ASSOCIATED WITH THE TROUGH HAS
BEGUN TO STRATIFY. A WEAK CIRCULATION IS EMBEDDED IN THE MONSOON
TROUGH TO THE SOUTHWEST OF KOSRAE NEAR 4N160E. CONVECTION
ASSOCIATED WITH THIS SYSTEM IS LOOSELY ORGANIZED AND PRIMARILY
LOCATED ON THE WEST SIDE OF THE CIRCULATION. KOSRAE IS LOCATED
BENEATH WEAK RIDGING.

LATEST FORECAST ISSUANCE FOLLOWS CONTINUITY WITH A FEW
ADJUSTMENTS. REDUCED FIRST PERIOD POPS FOR MAJURO TO ISOLATED
BASED ON WARMING/ STRATIFYING CLOUD TOPS UPSTREAM. DESPITE
THIS...KEPT SCATTERED POPS FOR FRIDAY BASED ON STRONG SIGNAL IN
THE GFS FOR REDEVELOPMENT OF CONVECTION WITHIN THE ZONE OF TRADE-
WIND CONVERGENCE ON THE DOWNSTREAM SIDE OF THE TROUGH. FORECAST
FOR KOSRAE MAINTAINS ISOLATED POPS THROUGH DAY 5 AS WEAK RIDGING
REMAINS THE PRIMARY PLAYER IN THE FORECAST. CONVECTION ASSOCIATED
WITH THE CIRCULATION SOUTHWEST OF KOSRAE HAS ALREADY SHIFTED TO
THE WEST OF POHNPEI. MADE MINOR ADJUSTMENTS TO THE WIND FORECAST
TO ACCOUNT FOR THE PASSAGE OF AN INVERTED TROUGH.

CONCERN CONTINUES TO REVOLVE AROUND A POSSIBLE HIGH SURF EVENT
FROM CHUUK EASTWARD TO MAJURO BEGINNING ON FRIDAY NIGHT OR
SATURDAY. WAVE WATCH MODEL GRAPHICAL AND TABULAR GUIDANCE BOTH
SUGGEST LONG PERIOD NORTH-NORTHEAST SWELL WILL BE BLOCKED BEFORE
THEY REACH MAJURO AND KOSRAE...WHILE POHNPEI AND CHUUK REMAIN
FULLY EXPOSED TO SWELL FROM THAT DIRECTION. REGARDLESS...HIGH
SURF ADVISORIES WILL BE NEEDED FOR AT LEAST CHUUK AND POHNPEI ON
FRIDAY.

WESTERN MICRONESIA...
CONVECTION IN THE MONSOON TROUGH TO THE WEST OF THE KOSRAE
CIRCULATION IS PASSING OVER CHUUK. STILL EXPECT THIS ROUND OF
CONVECTION TO WIND DOWN DURING THE NEXT 3 TO 6 HOURS. FLOW
PATTERN OVER WESTERN MICRONESIA IS BECOMING WEAK AND CHAOTIC.
MONSOON TROUGH PASSES TO THE NORTH OF YAP AND KOROR...BUT
CONVECTION DEVELOPING OVER AND SOUTH OF KOROR IS INDUCING MORE
TROUGHING. THIS HAS RESULTED IN WEAK RIDGING FORMING OVER YAP.
OTHERWISE...HAVE KEPT DRY BIAS IN THE FORECAST FOR ALL 3
LOCATIONS AS CONVECTION ACROSS WESTERN MICRONESIA IS CURRENTLY
MESOSCALE AND LOOSELY ORGANIZED... THEN ZONE OF BEST LOW-LEVEL
CONVERGENCE SHIFTS TO THE NORTH OF ALL 3 FORECAST LOCALES BY
TUESDAY. HAVE ADJUSTED TIMING OF SCATTERED SHOWERS FOR CHUUK TO
THIS EVENING ONLY BASED ON SATELLITE TRENDS. ADDED SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS TO THE KOROR FORECAST FOR THIS
EVENING ONLY TO ACCOUNT FOR THE PASSAGE OF A SMALL MCS.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF ADVISORY UNTIL 4 PM CHST SUNDAY FOR GUZ001>004.

MARIANAS WATERS...NONE.
&&

$$

STANKO/MCELROY/WILLIAMS







000
FXPQ60 PGUM 230713 AAA
AFDPQ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TIYAN GU
513 PM CHST THU OCT 23 2014

UPDATED TO ADD MICRONESIAN DISCUSSION SECTIONS

.MARIANAS SYNOPSIS...
A WEAK CIRCULATION IS CENTERED JUST SOUTHEAST OF GUAM NEAR 12.5N
AND 145.5E. SCATTERED SHOWERS OVER GUAM AND ROTA THIS MORNING
THIS MORNING DISSIPATED RAPIDLY BEFORE NOON. RADAR AND SATELLITE
IMAGERY SHOW MORE SHOWERS DEVELOPING ON THE DOWN SHEAR SIDE OF
THE CIRCULATION OVER THE COASTAL WATERS EAST OF GUAM. MOST OF THE
SHOWERS APPEAR TO BE CONCENTRATED ON THE EAST SIDE OF THE
CIRCULATION BETWEEN 10N AND 15N FROM 148E TO 150E.

&&

.DISCUSSION...
THE WEAK CIRCULATION JUST EAST OF GUAM IS EMBEDDED WITHIN THE
MONSOON TROUGH AND IS EXPECTED TO PASS OVER GUAM TONIGHT. FELT
GFS INITIALIZED WELL IN TERMS OF SPATIAL CHARACTERISTICS OF
CONVECTION THIS MORNING. GFS AND HIGHER RESOLUTION MODELS
INDICATE THAT MUCH OF THE SHOWER ACTIVITY ASSOCIATED WITH THE
SYSTEM WILL DEVELOP TO THE NORTH OF THE CIRCULATION CENTER OVER
TINIAN AND SAIPAN LATER TONIGHT SO OPTED FOR SCATTERED WORDING
LATE TONIGHT. THIS CORROBORATES WELL WITH CURRENT SATELLITE
IMAGERY SHOWING SHOWER ACTIVITY INCREASING EAST AND NORTH OF THE
CIRCULATION. UPPER-LEVEL DYNAMICS ARE NOT IDEAL FOR THUNDERSTORM
DEVELOPMENT BUT CANNOT RULE OUT A THUNDERSTORM OR TWO OVERNIGHT
NORTH OF ROTA. IN THE LONG TERM...GFS AND NAVGEM ARE STILL THE
DRIER SOLUTIONS COMPARED TO THE ECMWF. ECMWF INCREASES MOISTURE
AND SHOWERS AND DEVELOPS A BROAD CIRCULATION SOUTH OF THE
MARIANAS MORE AGGRESSIVELY THAN THE GFS AND NAVGEM OVER THE
WEEKEND. UNCERTAINTY STILL EXISTS REGARDING SHOWER COVERAGE
DURING THE 3 TO 5-DAY TIME FRAME BUT MAINTAINED THE DRIER
SCENARIO UNTIL MODELS COME INTO MORE OF A CONSENSUS DURING THE
NEXT SEVERAL RUNS.

&&

.MARINE...
TANAPAG AND RITIDIAN BUOYS SHOW N-NE SWELL CONTINUING TO SLOWLY
DIMINISH ACROSS THE MARIANAS. A SECOND...LONG-PERIOD NORTHEAST
SWELL EVENT WILL COMMENCE FRIDAY BEGINNING WITH SAIPAN. THIS WILL
CAUSE SURF TO RISE TO HAZARDOUS LEVELS FRIDAY AFTER A BRIEF DROP
IN SURF HEIGHTS TONIGHT. SURF HEIGHTS OF 7 TO 9 FEET ARE EXPECTED
THROUGH MUCH OF THE WEEKEND WITH SURF EXPECTED TO DROP BELOW
HAZARDOUS LEVELS SUNDAY AFTERNOON.

&&

.EASTERN MICRONESIA...
AN INVERTED SURFACE TROUGH IS APPROACHING MAJURO FROM THE EAST.
UPDATED MAJURO FORECAST THIS MORNING TO INCREASE SHOWER COVERAGE
TO SCATTERED...BUT CONVECTION ASSOCIATED WITH THE TROUGH HAS
BEGUN TO STRATIFY. A WEAK CIRCULATION IS EMBEDDED IN THE MONSOON
TROUGH TO THE SOUTHWEST OF KOSRAE NEAR 4N160E. CONVECTION
ASSOCIATED WITH THIS SYSTEM IS LOOSELY ORGANIZED AND PRIMARILY
LOCATED ON THE WEST SIDE OF THE CIRCULATION. KOSRAE IS LOCATED
BENEATH WEAK RIDGING.

LATEST FORECAST ISSUANCE FOLLOWS CONTINUITY WITH A FEW
ADJUSTMENTS. REDUCED FIRST PERIOD POPS FOR MAJURO TO ISOLATED
BASED ON WARMING/ STRATIFYING CLOUD TOPS UPSTREAM. DESPITE
THIS...KEPT SCATTERED POPS FOR FRIDAY BASED ON STRONG SIGNAL IN
THE GFS FOR REDEVELOPMENT OF CONVECTION WITHIN THE ZONE OF TRADE-
WIND CONVERGENCE ON THE DOWNSTREAM SIDE OF THE TROUGH. FORECAST
FOR KOSRAE MAINTAINS ISOLATED POPS THROUGH DAY 5 AS WEAK RIDGING
REMAINS THE PRIMARY PLAYER IN THE FORECAST. CONVECTION ASSOCIATED
WITH THE CIRCULATION SOUTHWEST OF KOSRAE HAS ALREADY SHIFTED TO
THE WEST OF POHNPEI. MADE MINOR ADJUSTMENTS TO THE WIND FORECAST
TO ACCOUNT FOR THE PASSAGE OF AN INVERTED TROUGH.

CONCERN CONTINUES TO REVOLVE AROUND A POSSIBLE HIGH SURF EVENT
FROM CHUUK EASTWARD TO MAJURO BEGINNING ON FRIDAY NIGHT OR
SATURDAY. WAVE WATCH MODEL GRAPHICAL AND TABULAR GUIDANCE BOTH
SUGGEST LONG PERIOD NORTH-NORTHEAST SWELL WILL BE BLOCKED BEFORE
THEY REACH MAJURO AND KOSRAE...WHILE POHNPEI AND CHUUK REMAIN
FULLY EXPOSED TO SWELL FROM THAT DIRECTION. REGARDLESS...HIGH
SURF ADVISORIES WILL BE NEEDED FOR AT LEAST CHUUK AND POHNPEI ON
FRIDAY.

&&

.WESTERN MICRONESIA...
CONVECTION IN THE MONSOON TROUGH TO THE WEST OF THE KOSRAE
CIRCULATION IS PASSING OVER CHUUK. STILL EXPECT THIS ROUND OF
CONVECTION TO WIND DOWN DURING THE NEXT 3 TO 6 HOURS. FLOW
PATTERN OVER WESTERN MICRONESIA IS BECOMING WEAK AND CHAOTIC.
MONSOON TROUGH PASSES TO THE NORTH OF YAP AND KOROR...BUT
CONVECTION DEVELOPING OVER AND SOUTH OF KOROR IS INDUCING MORE
TROUGHING. THIS HAS RESULTED IN WEAK RIDGING FORMING OVER YAP.
OTHERWISE...HAVE KEPT DRY BIAS IN THE FORECAST FOR ALL 3
LOCATIONS AS CONVECTION ACROSS WESTERN MICRONESIA IS CURRENTLY
MESOSCALE AND LOOSELY ORGANIZED... THEN ZONE OF BEST LOW-LEVEL
CONVERGENCE SHIFTS TO THE NORTH OF ALL 3 FORECAST LOCALES BY
TUESDAY. HAVE ADJUSTED TIMING OF SCATTERED SHOWERS FOR CHUUK TO
THIS EVENING ONLY BASED ON SATELLITE TRENDS. ADDED SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS TO THE KOROR FORECAST FOR THIS
EVENING ONLY TO ACCOUNT FOR THE PASSAGE OF A SMALL MCS.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF ADVISORY UNTIL 4 PM CHST SUNDAY FOR GUZ001>004.

MARIANAS WATERS...NONE.
&&

$$

WILLIAMS/MCELROY






000
FXPQ60 PGUM 230439
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
239 PM CHST THU OCT 23 2014

.MARIANAS SYNOPSIS...
A WEAK CIRCULATION IS CENTERED JUST SOUTHEAST OF GUAM NEAR 12.5N
AND 145.5E. SCATTERED SHOWERS OVER GUAM AND ROTA THIS MORNING
THIS MORNING DISSIPATED RAPIDLY BEFORE NOON. RADAR AND SATELLITE
IMAGERY SHOW MORE SHOWERS DEVELOPING ON THE DOWN SHEAR SIDE OF
THE CIRCULATION OVER THE COASTAL WATERS EAST OF GUAM. MOST OF THE
SHOWERS APPEAR TO BE CONCENTRATED ON THE EAST SIDE OF THE
CIRCULATION BETWEEN 10N AND 15N FROM 148E TO 150E.

&&

.DISCUSSION...
THE WEAK CIRCULATION JUST EAST OF GUAM IS EMBEDDED WITHIN THE
MONSOON TROUGH AND IS EXPECTED TO PASS OVER GUAM TONIGHT. FELT
GFS INITIALIZED WELL IN TERMS OF SPATIAL CHARACTERISTICS OF
CONVECTION THIS MORNING. GFS AND HIGHER RESOLUTION MODELS
INDICATE THAT MUCH OF THE SHOWER ACTIVITY ASSOCIATED WITH THE
SYSTEM WILL DEVELOP TO THE NORTH OF THE CIRCULATION CENTER OVER
TINIAN AND SAIPAN LATER TONIGHT SO OPTED FOR SCATTERED WORDING
LATE TONIGHT. THIS CORROBORATES WELL WITH CURRENT SATELLITE
IMAGERY SHOWING SHOWER ACTIVITY INCREASING EAST AND NORTH OF THE
CIRCULATION. UPPER-LEVEL DYNAMICS ARE NOT IDEAL FOR THUNDERSTORM
DEVELOPMENT BUT CANNOT RULE OUT A THUNDERSTORM OR TWO OVERNIGHT
NORTH OF ROTA. IN THE LONG TERM...GFS AND NAVGEM ARE STILL THE
DRIER SOLUTIONS COMPARED TO THE ECMWF. ECMWF INCREASES MOISTURE
AND SHOWERS AND DEVELOPS A BROAD CIRCULATION SOUTH OF THE
MARIANAS MORE AGGRESSIVELY THAN THE GFS AND NAVGEM OVER THE
WEEKEND. UNCERTAINTY STILL EXISTS REGARDING SHOWER COVERAGE
DURING THE 3 TO 5-DAY TIME FRAME BUT MAINTAINED THE DRIER
SCENARIO UNTIL MODELS COME INTO MORE OF A CONSENSUS DURING THE
NEXT SEVERAL RUNS.

&&

.MARINE...
TANAPAG AND RITIDIAN BUOYS SHOW N-NE SWELL CONTINUING TO SLOWLY
DIMINISH ACROSS THE MARIANAS. A SECOND...LONG-PERIOD NORTHEAST
SWELL EVENT WILL COMMENCE FRIDAY BEGINNING WITH SAIPAN. THIS WILL
CAUSE SURF TO RISE TO HAZARDOUS LEVELS FRIDAY AFTER A BRIEF DROP
IN SURF HEIGHTS TONIGHT. SURF HEIGHTS OF 7 TO 9 FEET ARE EXPECTED
THROUGH MUCH OF THE WEEKEND WITH SURF EXPECTED TO DROP BELOW
HAZARDOUS LEVELS SUNDAY AFTERNOON.

&&

.EASTERN MICRONESIA...WILL BE UPDATED LATER.


&&

.WESTERN MICRONESIA...WILL BE UPDATED LATER.


&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF ADVISORY UNTIL 4 PM CHST SUNDAY FOR GUZ001>004.

MARIANAS WATERS...NONE.
&&

$$

WILLIAMS/MCELROY







000
FXPQ60 PGUM 230439
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
239 PM CHST THU OCT 23 2014

.MARIANAS SYNOPSIS...
A WEAK CIRCULATION IS CENTERED JUST SOUTHEAST OF GUAM NEAR 12.5N
AND 145.5E. SCATTERED SHOWERS OVER GUAM AND ROTA THIS MORNING
THIS MORNING DISSIPATED RAPIDLY BEFORE NOON. RADAR AND SATELLITE
IMAGERY SHOW MORE SHOWERS DEVELOPING ON THE DOWN SHEAR SIDE OF
THE CIRCULATION OVER THE COASTAL WATERS EAST OF GUAM. MOST OF THE
SHOWERS APPEAR TO BE CONCENTRATED ON THE EAST SIDE OF THE
CIRCULATION BETWEEN 10N AND 15N FROM 148E TO 150E.

&&

.DISCUSSION...
THE WEAK CIRCULATION JUST EAST OF GUAM IS EMBEDDED WITHIN THE
MONSOON TROUGH AND IS EXPECTED TO PASS OVER GUAM TONIGHT. FELT
GFS INITIALIZED WELL IN TERMS OF SPATIAL CHARACTERISTICS OF
CONVECTION THIS MORNING. GFS AND HIGHER RESOLUTION MODELS
INDICATE THAT MUCH OF THE SHOWER ACTIVITY ASSOCIATED WITH THE
SYSTEM WILL DEVELOP TO THE NORTH OF THE CIRCULATION CENTER OVER
TINIAN AND SAIPAN LATER TONIGHT SO OPTED FOR SCATTERED WORDING
LATE TONIGHT. THIS CORROBORATES WELL WITH CURRENT SATELLITE
IMAGERY SHOWING SHOWER ACTIVITY INCREASING EAST AND NORTH OF THE
CIRCULATION. UPPER-LEVEL DYNAMICS ARE NOT IDEAL FOR THUNDERSTORM
DEVELOPMENT BUT CANNOT RULE OUT A THUNDERSTORM OR TWO OVERNIGHT
NORTH OF ROTA. IN THE LONG TERM...GFS AND NAVGEM ARE STILL THE
DRIER SOLUTIONS COMPARED TO THE ECMWF. ECMWF INCREASES MOISTURE
AND SHOWERS AND DEVELOPS A BROAD CIRCULATION SOUTH OF THE
MARIANAS MORE AGGRESSIVELY THAN THE GFS AND NAVGEM OVER THE
WEEKEND. UNCERTAINTY STILL EXISTS REGARDING SHOWER COVERAGE
DURING THE 3 TO 5-DAY TIME FRAME BUT MAINTAINED THE DRIER
SCENARIO UNTIL MODELS COME INTO MORE OF A CONSENSUS DURING THE
NEXT SEVERAL RUNS.

&&

.MARINE...
TANAPAG AND RITIDIAN BUOYS SHOW N-NE SWELL CONTINUING TO SLOWLY
DIMINISH ACROSS THE MARIANAS. A SECOND...LONG-PERIOD NORTHEAST
SWELL EVENT WILL COMMENCE FRIDAY BEGINNING WITH SAIPAN. THIS WILL
CAUSE SURF TO RISE TO HAZARDOUS LEVELS FRIDAY AFTER A BRIEF DROP
IN SURF HEIGHTS TONIGHT. SURF HEIGHTS OF 7 TO 9 FEET ARE EXPECTED
THROUGH MUCH OF THE WEEKEND WITH SURF EXPECTED TO DROP BELOW
HAZARDOUS LEVELS SUNDAY AFTERNOON.

&&

.EASTERN MICRONESIA...WILL BE UPDATED LATER.


&&

.WESTERN MICRONESIA...WILL BE UPDATED LATER.


&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF ADVISORY UNTIL 4 PM CHST SUNDAY FOR GUZ001>004.

MARIANAS WATERS...NONE.
&&

$$

WILLIAMS/MCELROY







000
FXPQ60 PGUM 222131
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
731 AM CHST THU OCT 23 2014

.UPDATE...
A WEAK DISTURBANCE PASSING OVER THE MARIANAS WILL BRING SCATTERED
SHOWERS AND POSSIBLE THUNDERSTORMS TO GUAM AND ROTA WATERS THIS
MORNING.

&&

.PREV DISCUSSION... /ISSUED 652 AM CHST THU OCT 23 2014/

MARIANAS SYNOPSIS...
RADAR SHOWS WIDELY SCATTERED SHOWERS JUST EAST AND SOUTHEAST OF THE
GUAM MARINE ZONE AND ISOLATED SHOWERS ELSEWHERE. SATELLITE SHOWS A
FEW HEAVIER SHOWERS FARTHER SOUTHEAST OF GUAM NEAR 13N147E...AND A
WEAK CIRCULATION IS APPARENTLY NEAR 12N146E. VAD GRADIENT WINDS ARE
NE ABOUT 10 KT. SAIPAN BUOY STILL SHOWS A NNE SWELL OF 6 TO 7 FEET.

DISCUSSION...
CLOUDINESS HAS INCREASED ACROSS THE AREA AND A FEW MORE SHOWERS
COULD ALSO RESULT IF THE SHOWERS TO OUR SOUTHEAST MOVE INTO THE
FORECAST ZONES. LIGHT EAST TO SOUTHEAST WINDS ARE EXPECTED FOR THE
MARIANA ISLANDS WHILE THE WEATHER PATTERN SEEMS TO BE SHIFTING INTO
A MORE ACTIVE MODE ACROSS MICRONESIA. MODELS INDICATE MORE ACTIVE
WEATHER ACROSS THE SOUTHERN PARTS OF THE REGION AS THE CIRCULATION
NOW JUST SE OF GUAM MOVES ROUGHLY TOWARD THE WEST EVEN WHILE A
CIRCULATION OVER EASTERN MICRONESIA ALSO FOLLOWS WESTWARD.

MARINE...
HIGH SURF ADVISORY REMAINS IN EFFECT WHILE LONG-PERIOD NNE TO NE
SWELL CONTINUES FOR THE NEXT FEW DAYS. MARINE GRIDS WERE ADJUSTED
FOR INITIAL CONDITIONS AND WW3 GUIDANCE. WIND GRIDS WERE REFRESHED
WITH LATEST GFS75 DATA.

EASTERN MICRONESIA...
A SURFACE TROUGH EXTENDS SOUTHEASTWARD FROM A WEAK CIRCULATION JUST
SOUTH OF GUAM AT 12N146E TO ANOTHER CIRCULATION CENTERED WEST OF
KOSRAE AT 5N163E. MODEST SURFACE CONVERGENCE ALONG THE NORTHERN
PERIPHERY OF THE CIRCULATION NEAR KOSRAE WILL KEEP ISOLATED
CONVECTION OVER POHNPEI UNTIL FRIDAY. AFTER THE PASSAGE OF THIS
CIRCULATION TO THE SOUTH OF POHNPEI BY FRIDAY EVENING...A BRIEF
PERIOD OF FAIR WEATHER IS POSSIBLE. FARTHER EAST...ANOTHER SURFACE
TROUGH CAN BE SEEN ON THE LATEST IR SATELLITE IMAGERY STRETCHING
NORTHEASTWARD FROM NEAR TARAWA ATOLL AT 1N170E TO BEYOND 180 AT 11N.
WIDELY SCATTERED SHOWERS AHEAD OF THIS TROUGH ARE ALREADY VISIBLE
NEAR 167E EAST OF KOSRAE...AND SHOULD REACH THAT ISLAND BY
TONIGHT. THE BULK OF WET WEATHER RELATED TO THIS SAME TROUGH WILL
ALSO ARRIVE AT MAJURO BY LATE THIS AFTERNOON AS WELL. AS THIS
TROUGH PUSHES FARTHER WESTWARD ON SATURDAY...IT WILL PROLONG
SHOWERY CONDITIONS NEAR KOSRAE THRU SATURDAY NIGHT AND SPREAD THEM
TO POHNPEI BY SATURDAY EVENING. A SURFACE RIDGE FOLLOWING BEHIND
THE TROUGH MIGHT BRING IN DRIER WEATHER FOR MAJURO BY
SATURDAY...AND THEN FOR KOSRAE AND POHNPEI ON SUNDAY.

A STRONG LOW PRESSURE SYSTEM IS DRIFTING EASTWARD FROM WELL NORTH OF
WAKE ISLAND AT 34N170E. LONG-PERIOD NNE SWELLS GENERATED BY NEAR
GALE WINDS WEST OF ITS CENTER ARE EXPECTED TO MIGRATE ACROSS CHUUK
AND POHNPEI STATES FROM FRIDAY EVENING TO SUNDAY. THIS COULD CREATE
HAZARDOUS SURF FOR BOTH STATES WHICH NEEDS TO BE MONITORED CLOSELY.
AS THIS SAME LOW PRESSURE SYSTEM CROSSES THE DATE LINE ON FRIDAY...
MODERATE NNE SWELLS WILL ALSO APPROACH THE MARSHALL ISLANDS. EVEN
THOUGH THESE NNE SWELLS WILL NOT BE HIGH ENOUGH TO CAUSE HAZARDOUS
SURF...THEY COULD COMBINE WITH SPRING HIGH TIDES TO CAUSE COASTAL
INUNDATIONS ACROSS THE MARSHALLS FROM SATURDAY TO MONDAY. THIS
SITUATION WILL ALSO NEED TO BE WATCHED VERY CLOSELY AND ISSUE A
SPECIAL WEATHER STATEMENT IF NECESSARY.

WESTERN MICRONESIA...
A SURFACE RIDGE OVER CHUUK SHOULD BE ABLE TO PROVIDE ONE MORE DAY OF
PARTLY SUNNY SKIES TODAY. CONVERGING WINDS BETWEEN THIS RIDGE AND A
CIRCULATION NEAR KOSRAE ARE ALREADY SPARKING DEEP CONVECTION EAST OF
WENO ISLAND. ANTICIPATE THIS CONVECTION TO IMPACT CHUUK LAGOON BY
LATER THIS EVENING. WEATHER MIGHT IMPROVE SLIGHTLY AS THE CIRCULATION
PASSES SOUTH OF CHUUK LAGOON ON SATURDAY. FOR EARLY NEXT WEEK...
WEAKER SOUTHEASTERLY TRADES IN THE WAKE OF THE CIRCULATION COULD
PROMOTE QUIETER WEATHER. REFER TO THE SECOND PARAGRAPH UNDER EASTERN
MICRONESIA DISCUSSION ABOVE FOR POSSIBLE HAZARDOUS SURF CONDITIONS
BY FRIDAY.

BASED ON LATEST IR SATELLITE LOOP THIS MORNING...ANOTHER SURFACE
TROUGH MEANDERS EASTWARD FROM SOUTHERN PHILIPPINES TO NEAR KOROR
INTO A CIRCULATION CENTERED SOUTH OF YAP NEAR 6N140E. DESPITE
MAINLY GENTLE WINDS ASSOCIATED WITH THESE FEATURES...THE DIVERGENT
UPPER WINDS NEAR THE SOUTHWESTERN QUADRANT OF A HIGH SOUTHEAST OF
YAP ARE ENHANCING CONVECTION SOUTH OF KOROR. THIS TREND WILL
CONTINUE THRU FRIDAY...AND A FEW THUNDERSTORMS COULD SPILL
NORTHWARD INTO KOROR WATERS TODAY. AS THE HIGH GRADUALLY SHIFTS
WESTWARD TONIGHT AND FRIDAY...CONVECTION SHOULD STAY FARTHER SOUTH.
WITH THIS IN MIND...WEATHER NEAR BOTH LOCATIONS SHOULD STAY MAINLY
DRY THRU SATURDAY. BY EARLY NEXT WEEK...THE SURFACE TROUGH AND
CIRCULATION WILL FINALLY LIFT NORTHWEST OF THE REGION AND SUSTAIN
PARTLY CLOUDY SKIES.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF ADVISORY UNTIL 4 PM CHST SUNDAY FOR GUZ001>004.

MARIANAS WATERS...NONE.
&&

$$

WILLIAMS/SIMPSON/CHAN







000
FXPQ60 PGUM 222052
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
652 AM CHST THU OCT 23 2014

.MARIANAS SYNOPSIS...
RADAR SHOWS WIDELY SCATTERED SHOWERS JUST EAST AND SOUTHEAST OF THE
GUAM MARINE ZONE AND ISOLATED SHOWERS ELSEWHERE. SATELLITE SHOWS A
FEW HEAVIER SHOWERS FARTHER SOUTHEAST OF GUAM NEAR 13N147E...AND A
WEAK CIRCULATION IS APPARENTLY NEAR 12N146E. VAD GRADIENT WINDS ARE
NE ABOUT 10 KT. SAIPAN BUOY STILL SHOWS A NNE SWELL OF 6 TO 7 FEET.

&&

.DISCUSSION...
CLOUDINESS HAS INCREASED ACROSS THE AREA AND A FEW MORE SHOWERS
COULD ALSO RESULT IF THE SHOWERS TO OUR SOUTHEAST MOVE INTO THE
FORECAST ZONES. LIGHT EAST TO SOUTHEAST WINDS ARE EXPECTED FOR THE
MARIANA ISLANDS WHILE THE WEATHER PATTERN SEEMS TO BE SHIFTING INTO
A MORE ACTIVE MODE ACROSS MICRONESIA. MODELS INDICATE MORE ACTIVE
WEATHER ACROSS THE SOUTHERN PARTS OF THE REGION AS THE CIRCULATION
NOW JUST SE OF GUAM MOVES ROUGHLY TOWARD THE WEST EVEN WHILE A
CIRCULATION OVER EASTERN MICRONESIA ALSO FOLLOWS WESTWARD.

&&

.MARINE...
HIGH SURF ADVISORY REMAINS IN EFFECT WHILE LONG-PERIOD NNE TO NE
SWELL CONTINUES FOR THE NEXT FEW DAYS. MARINE GRIDS WERE ADJUSTED
FOR INITIAL CONDITIONS AND WW3 GUIDANCE. WIND GRIDS WERE REFRESHED
WITH LATEST GFS75 DATA.

&&

.EASTERN MICRONESIA...
A SURFACE TROUGH EXTENDS SOUTHEASTWARD FROM A WEAK CIRCULATION JUST
SOUTH OF GUAM AT 12N146E TO ANOTHER CIRCULATION CENTERED WEST OF
KOSRAE AT 5N163E. MODEST SURFACE CONVERGENCE ALONG THE NORTHERN
PERIPHERY OF THE CIRCULATION NEAR KOSRAE WILL KEEP ISOLATED
CONVECTION OVER POHNPEI UNTIL FRIDAY. AFTER THE PASSAGE OF THIS
CIRCULATION TO THE SOUTH OF POHNPEI BY FRIDAY EVENING...A BRIEF
PERIOD OF FAIR WEATHER IS POSSIBLE. FARTHER EAST...ANOTHER SURFACE
TROUGH CAN BE SEEN ON THE LATEST IR SATELLITE IMAGERY STRETCHING
NORTHEASTWARD FROM NEAR TARAWA ATOLL AT 1N170E TO BEYOND 180 AT 11N.
WIDELY SCATTERED SHOWERS AHEAD OF THIS TROUGH ARE ALREADY VISIBLE
NEAR 167E EAST OF KOSRAE...AND SHOULD REACH THAT ISLAND BY
TONIGHT. THE BULK OF WET WEATHER RELATED TO THIS SAME TROUGH WILL
ALSO ARRIVE AT MAJURO BY LATE THIS AFTERNOON AS WELL. AS THIS
TROUGH PUSHES FARTHER WESTWARD ON SATURDAY...IT WILL PROLONG
SHOWERY CONDITIONS NEAR KOSRAE THRU SATURDAY NIGHT AND SPREAD THEM
TO POHNPEI BY SATURDAY EVENING. A SURFACE RIDGE FOLLOWING BEHIND
THE TROUGH MIGHT BRING IN DRIER WEATHER FOR MAJURO BY
SATURDAY...AND THEN FOR KOSRAE AND POHNPEI ON SUNDAY.

A STRONG LOW PRESSURE SYSTEM IS DRIFTING EASTWARD FROM WELL NORTH OF
WAKE ISLAND AT 34N170E. LONG-PERIOD NNE SWELLS GENERATED BY NEAR
GALE WINDS WEST OF ITS CENTER ARE EXPECTED TO MIGRATE ACROSS CHUUK
AND POHNPEI STATES FROM FRIDAY EVENING TO SUNDAY. THIS COULD CREATE
HAZARDOUS SURF FOR BOTH STATES WHICH NEEDS TO BE MONITORED CLOSELY.
AS THIS SAME LOW PRESSURE SYSTEM CROSSES THE DATE LINE ON FRIDAY...
MODERATE NNE SWELLS WILL ALSO APPROACH THE MARSHALL ISLANDS. EVEN
THOUGH THESE NNE SWELLS WILL NOT BE HIGH ENOUGH TO CAUSE HAZARDOUS
SURF...THEY COULD COMBINE WITH SPRING HIGH TIDES TO CAUSE COASTAL
INUNDATIONS ACROSS THE MARSHALLS FROM SATURDAY TO MONDAY. THIS
SITUATION WILL ALSO NEED TO BE WATCHED VERY CLOSELY AND ISSUE A
SPECIAL WEATHER STATEMENT IF NECESSARY.

&&

.WESTERN MICRONESIA...
A SURFACE RIDGE OVER CHUUK SHOULD BE ABLE TO PROVIDE ONE MORE DAY OF
PARTLY SUNNY SKIES TODAY. CONVERGING WINDS BETWEEN THIS RIDGE AND A
CIRCULATION NEAR KOSRAE ARE ALREADY SPARKING DEEP CONVECTION EAST OF
WENO ISLAND. ANTICIPATE THIS CONVECTION TO IMPACT CHUUK LAGOON BY
LATER THIS EVENING. WEATHER MIGHT IMPROVE SLIGHTLY AS THE CIRCULATION
PASSES SOUTH OF CHUUK LAGOON ON SATURDAY. FOR EARLY NEXT WEEK...
WEAKER SOUTHEASTERLY TRADES IN THE WAKE OF THE CIRCULATION COULD
PROMOTE QUIETER WEATHER. REFER TO THE SECOND PARAGRAPH UNDER EASTERN
MICRONESIA DISCUSSION ABOVE FOR POSSIBLE HAZARDOUS SURF CONDITIONS
BY FRIDAY.

BASED ON LATEST IR SATELLITE LOOP THIS MORNING...ANOTHER SURFACE
TROUGH MEANDERS EASTWARD FROM SOUTHERN PHILIPPINES TO NEAR KOROR
INTO A CIRCULATION CENTERED SOUTH OF YAP NEAR 6N140E. DESPITE
MAINLY GENTLE WINDS ASSOCIATED WITH THESE FEATURES...THE DIVERGENT
UPPER WINDS NEAR THE SOUTHWESTERN QUADRANT OF A HIGH SOUTHEAST OF
YAP ARE ENHANCING CONVECTION SOUTH OF KOROR. THIS TREND WILL
CONTINUE THRU FRIDAY...AND A FEW THUNDERSTORMS COULD SPILL
NORTHWARD INTO KOROR WATERS TODAY. AS THE HIGH GRADUALLY SHIFTS
WESTWARD TONIGHT AND FRIDAY...CONVECTION SHOULD STAY FARTHER SOUTH.
WITH THIS IN MIND...WEATHER NEAR BOTH LOCATIONS SHOULD STAY MAINLY
DRY THRU SATURDAY. BY EARLY NEXT WEEK...THE SURFACE TROUGH AND
CIRCULATION WILL FINALLY LIFT NORTHWEST OF THE REGION AND SUSTAIN
PARTLY CLOUDY SKIES.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF ADVISORY UNTIL 4 PM CHST SUNDAY FOR GUZ001>004.

MARIANAS WATERS...NONE.
&&

$$

SIMPSON/CHAN







000
FXPQ60 PGUM 221916
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
516 AM CHST THU OCT 23 2014

.MARIANAS SYNOPSIS...
RADAR SHOWS WIDELY SCATTERED SHOWERS JUST EAST AND SOUTHEAST OF THE
GUAM MARINE ZONE AND ISOLATED SHOWERS ELSEWHERE. SATELLITE SHOWS A
FEW HEAVIER SHOWERS FARTHER SOUTHEAST OF GUAM NEAR 13N147E...AND A
WEAK CIRCULATION IS APPARENTLY NEAR 12N146E. VAD GRADIENT WINDS ARE
NE ABOUT 10 KT. SAIPAN BUOY STILL SHOWS A NNE SWELL OF 6 TO 7 FEET.

&&

.DISCUSSION...
CLOUDINESS HAS INCREASED ACROSS THE AREA AND A FEW MORE SHOWERS
COULD ALSO RESULT IF THE SHOWERS TO OUR SOUTHEAST MOVE INTO THE
FORECAST ZONES. LIGHT EAST TO SOUTHEAST WINDS ARE EXPECTED FOR THE
MARIANA ISLANDS WHILE THE WEATHER PATTERN SEEMS TO BE SHIFTING INTO
A MORE ACTIVE MODE ACROSS MICRONESIA. MODELS INDICATE MORE ACTIVE
WEATHER ACROSS THE SOUTHERN PARTS OF THE REGION AS THE CIRCULATION
NOW JUST SE OF GUAM MOVES ROUGHLY TOWARD THE WEST EVEN WHILE A
CIRCULATION OVER EASTERN MICRONESIA ALSO FOLLOWS WESTWARD.

&&

.MARINE...
HIGH SURF ADVISORY REMAINS IN EFFECT WHILE LONG-PERIOD NNE TO NE
SWELL CONTINUES FOR THE NEXT FEW DAYS. MARINE GRIDS WERE ADJUSTED
FOR INITIAL CONDITIONS AND WW3 GUIDANCE. WIND GRIDS WERE REFRESHED
WITH LATEST GFS75 DATA.

&&

.EASTERN MICRONESIA...WILL BE ADDED LATER.


&&

.WESTERN MICRONESIA...WILL BE ADDED LATER.


&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF ADVISORY UNTIL 4 PM CHST SUNDAY FOR GUZ001>004.

MARIANAS WATERS...NONE.
&&

$$

SIMPSON/CHAN







000
FXPQ60 PGUM 220944 CCA
AFDPQ

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE TIYAN GU
427 PM CHST WED OCT 22 2014

CORRECTED TYPO

.MARIANAS SYNOPSIS...
A SHEAR LINE ALONG WITH A WELL-DEFINED LINE OF SHOWERS AND
THUNDERSTORMS ARE PRESENT ACROSS THE FAR NORTHERN MARIANAS. A WEAK
CIRCULATION AND TROUGH ARE FOUND SOUTHEAST OF GUAM. SHOWERS
ASSOCIATED WITH THE TROUGH ARE APPROACHING EASTERN MARIANAS COASTAL
WATERS.

&&

.DISCUSSION...
THE CIRCULATION AND SURFACE TROUGH SOUTHEAST OF THE MARIANAS WILL
SLOWLY PUSH NORTHWARD...THEN WESTWARD THROUGH THURSDAY. WINDS WILL
VEER FROM THE EAST TO THE SOUTHEAST THURSDAY AND INTRODUCE DEEPER
TROPICAL MOISTURE TO THE MARIANAS. ADJUSTED SKY COVER TO MOSTLY
CLOUDY THURSDAY THROUGH FRIDAY NIGHT TO ACCOUNT FOR THE PASSAGE OF
THE CIRCULATION/TROUGH. SATELLITE AND RADAR IMAGERY INDICATE ONLY
ISOLATED SHOWER COVERAGE AT THE MOMENT. GFS AND NAVGEM ARE STILL THE
DRIER NWP SOLUTIONS WHILE THE ECMWF HOLDS OFF ON INCREASED SHOWERS
UNTIL FRIDAY NIGHT. UNCERTAINTY EXISTS REGARDING THIS SYSTEM SINCE
IT IS A SMALL FEATURE AND PROBABLY NOT BEING HANDLED WELL BY MODELS.
ONCOMING SHIFT SHOULD ASSESS IF AN UPDATE IS NEEDED IN CASE SHOWERS
INCREASE FASTER THAN EXPECTED. FOR NOW...ONLY ISOLATED SHOWERS ARE
EXPECTED THU THROUGH FRI NIGHT OWING TO AT LEAST SOME CONSISTENCY TO
THE GFS AND NAVGEM RUNS OVER THE LAST 24 HOURS. MODEL AGREEMENT
BECOMES POOR AFTER THE PASSAGE OF THE CIRCULATION/TROUGH OVER THE
SOUTHERN MARIANAS WITH ECMWF KEEPING THE AREA UNDER AMPLE MOISTURE
AND WIDESPREAD SHOWER ACTIVITY WHILE GFS AND NAVGEM CONTINUE TO BE
THE LESS AGGRESSIVE FORECAST...EVEN IN THE LONG TERM. THE FORECAST
FOR NEXT WEEK IS LARGELY PERSISTENCE WITH A DRY TRADE-WIND PATTERN
EMERGING. A FEW MORE MODEL RUNS WILL BE NEEDED BEFORE A CONSENSUS
CAN BE MADE REGARDING ANY CHANGES IN THE FORECAST FOR NEXT WEEK.

&&

.MARINE...
SAIPAN BUOY SHOWED A RAPID RISE IN SEAS OVERNIGHT AS THE NORTH-
NORTHEAST SWELL BUILT IN SAIPAN WATERS. SWELL HAS REACHED GUAM AND
HAS BEEN SLIGHTLY LARGER THAN WW3 MODEL OUTPUT WITH SAIPAN BUOY
INDICATING A 7-FOOT 12 SECOND NNE SWELL. THUS...A HIGH SURF ADVISORY
WAS ISSUED THIS MORNING WITH SURF HEIGHTS OF 8 TO 9 FEET LIKELY
CONTINUING OVERNIGHT. SURF IS EXPECTED TO FALL SLIGHTLY THURSDAY BUT
A SECONDARY LONG-PERIOD SWELL FROM THE NORTHEAST WILL INCREASE
FRIDAY BRINGING SURF TO ADVISORY LEVELS ONCE AGAIN. SURF SHOULD FALL
BELOW ADVISORY LEVELS LATE SATURDAY NIGHT OR EARLY SUNDAY MORNING.

&&

.EASTERN MICRONESIA...
AN AREA OF SHOWERS AND THUNDERSTORMS PUSHED ACROSS POHNPEI TODAY.
SATELLITE IMAGERY SHOWED THAT THIS AREA WAS WEAKENING BUT LINGERING
SCATTERED SHOWERS ARE LIKELY FOR AT LEAST PART OF THE NIGHT. WHILE
THE CHANCE OF THUNDERSTORMS IS LOW...A FEW MAY OCCUR SO ADDED A
SLIGHT CHANCE OF THUNDERSTORMS TO THE POHNPEI FORECAST FOR TONIGHT.
LOW-LEVEL CONVERGENCE WILL KEEP SKIES MOSTLY CLOUDY ACROSS POHNPEI
THROUGH SATURDAY.

A SURFACE TROUGH IS STRETCHED ACROSS THE MARSHALL ISLANDS. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS COULD BE FOUND SOUTH OF MAJURO
THIS AFTERNOON. WHILE THE BULK OF THE ACTIVITY WILL REMAIN SOUTH OF
MAJURO...IT WILL PRODUCE ISOLATED SHOWERS AND A SLIGHT CHANCE OF
THUNDERSTORMS TONIGHT THROUGH THURSDAY NIGHT.

THIS SAME TROUGH WILL MOVE WEST AND CAUSE WINDS TO BECOME NORTHEAST
AT KOSRAE THURSDAY NIGHT. IT WILL BRING SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS TO KOSRAE FRIDAY AND FRIDAY NIGHT. HIGH
PRESSURE WILL BUILD ACROSS KOSRAE AND MAJURO SATURDAY AND SUNDAY.

&&

.WESTERN MICRONESIA...
A SURFACE TROUGH OF LOW PRESSURE CONTINUES TO STRETCH ACROSS THE
WESTERN HALF OF MICRONESIA. THE TROUGH AXIS WAS NORTH OF 10N.
CONVERGENCE SOUTH OF THE TROUGH BROUGHT SOME PATCHES OF SHOWERS AND
THUNDERSTORMS ACROSS PALAU AND YAP THIS AFTERNOON. WHILE ISOLATED
SHOWERS ARE EXPECTED TO BE THE PREDOMINANT COVERAGE... ISOLATED
THUNDERSTORMS ARE ALSO POSSIBLE ACROSS PALAU TONIGHT.

A CIRCULATION COULD BE FOUND ALONG THE TROUGH JUST SOUTH OF GUAM
THIS AFTERNOON. THIS TROUGH WILL PUSH SOUTHWEST TOWARD YAP. MODELS
SHOW IT WILL PASS CLOSE TO YAP ON THURSDAY. AT THIS TIME THE MODELS
KEEP THE WEATHER RATHER BENIGN NEAR THE CENTER OF THE CIRCULATION.
THE CIRCULATION LOOKS AS THOUGH IT WILL PUSH THE SHOWERS NOW NEAR
PALAU AND YAP FURTHER SOUTHWARD AS IT MOVES OVER YAP. THE
CIRCULATION WILL MOVE WEST TO 130E BY FRIDAY. IN THE WAKE OF THE
CIRCULATION...EAST TRADE WINDS WILL BUILD ACROSS PALAU AND YAP BY
THE END OF THE WEEK.

THE SOUTHWEST WINDS AT CHUUK TODAY WILL GIVE WAY TO NORTHEAST TRADE
WINDS THURSDAY NIGHT. FAIR WEATHER WILL PREVAIL ACROSS CHUUK THROUGH
THURSDAY NIGHT. MODELS SHOW A CIRCULATION DEVELOPING SOUTH OF CHUUK
THIS WEEKEND. WHILE MOST OF THE ACTIVITY WILL REMAIN SOUTH OF
CHUUK...MOSTLY CLOUDY SKIES AND A SLIGHT CHANCE THUNDERSTORMS WILL
PREVAIL FROM FRIDAY THROUGH MONDAY.

STRONG WINDS ASSOCIATED WITH A STORM SYSTEM IN THE NORTH PACIFIC
PRODUCED SWELLS THAT HAVE GENERATED HIGH SURF ACROSS THE MARIANAS
THIS AFTERNOON. MODELS SHOW LONG-PERIOD SWELLS PUSHING ACROSS YAP
AND PALAU SOMETIME THIS WEEKEND. AT THIS TIME...THESE SWELLS DO NOT
APPEAR TO BE HIGH ENOUGH TO GENERATE HAZARDOUS SURF AT THESE TWO
LOCATIONS. THIS SHOULD BE WATCHED AS THESE SWELLS WERE NOT EXPECTED
TO PRODUCE HAZARDOUS SURF ACROSS THE MARIANAS. AT ANY RATE EVEN IF
HAZARDOUS SURF DOES NOT OCCUR...THESE LONG PERIOD SWELLS...UP TO 14
SECONDS...MAY STILL PRODUCE A HIGHER RIP CURRENT RISK THIS WEEKEND.
THE SAME WAVE MODELS ALSO SHOW THE SURF POSSIBLY APPROACHING
HAZARDOUS AT CHUUK LATE FRIDAY NIGHT. AGAIN...EVEN IF SURF DOES NOT
REACH HAZARDOUS LEVELS...THE RIP CURRENT RISK WOULD LIKELY INCREASE.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF ADVISORY UNTIL 4 PM CHST SUNDAY FOR GUZ001>004.

MARIANAS WATERS...NONE.
&&

$$

WILLIAMS/ZIOBRO







000
FXPQ60 PGUM 220944 CCA
AFDPQ

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE TIYAN GU
427 PM CHST WED OCT 22 2014

CORRECTED TYPO

.MARIANAS SYNOPSIS...
A SHEAR LINE ALONG WITH A WELL-DEFINED LINE OF SHOWERS AND
THUNDERSTORMS ARE PRESENT ACROSS THE FAR NORTHERN MARIANAS. A WEAK
CIRCULATION AND TROUGH ARE FOUND SOUTHEAST OF GUAM. SHOWERS
ASSOCIATED WITH THE TROUGH ARE APPROACHING EASTERN MARIANAS COASTAL
WATERS.

&&

.DISCUSSION...
THE CIRCULATION AND SURFACE TROUGH SOUTHEAST OF THE MARIANAS WILL
SLOWLY PUSH NORTHWARD...THEN WESTWARD THROUGH THURSDAY. WINDS WILL
VEER FROM THE EAST TO THE SOUTHEAST THURSDAY AND INTRODUCE DEEPER
TROPICAL MOISTURE TO THE MARIANAS. ADJUSTED SKY COVER TO MOSTLY
CLOUDY THURSDAY THROUGH FRIDAY NIGHT TO ACCOUNT FOR THE PASSAGE OF
THE CIRCULATION/TROUGH. SATELLITE AND RADAR IMAGERY INDICATE ONLY
ISOLATED SHOWER COVERAGE AT THE MOMENT. GFS AND NAVGEM ARE STILL THE
DRIER NWP SOLUTIONS WHILE THE ECMWF HOLDS OFF ON INCREASED SHOWERS
UNTIL FRIDAY NIGHT. UNCERTAINTY EXISTS REGARDING THIS SYSTEM SINCE
IT IS A SMALL FEATURE AND PROBABLY NOT BEING HANDLED WELL BY MODELS.
ONCOMING SHIFT SHOULD ASSESS IF AN UPDATE IS NEEDED IN CASE SHOWERS
INCREASE FASTER THAN EXPECTED. FOR NOW...ONLY ISOLATED SHOWERS ARE
EXPECTED THU THROUGH FRI NIGHT OWING TO AT LEAST SOME CONSISTENCY TO
THE GFS AND NAVGEM RUNS OVER THE LAST 24 HOURS. MODEL AGREEMENT
BECOMES POOR AFTER THE PASSAGE OF THE CIRCULATION/TROUGH OVER THE
SOUTHERN MARIANAS WITH ECMWF KEEPING THE AREA UNDER AMPLE MOISTURE
AND WIDESPREAD SHOWER ACTIVITY WHILE GFS AND NAVGEM CONTINUE TO BE
THE LESS AGGRESSIVE FORECAST...EVEN IN THE LONG TERM. THE FORECAST
FOR NEXT WEEK IS LARGELY PERSISTENCE WITH A DRY TRADE-WIND PATTERN
EMERGING. A FEW MORE MODEL RUNS WILL BE NEEDED BEFORE A CONSENSUS
CAN BE MADE REGARDING ANY CHANGES IN THE FORECAST FOR NEXT WEEK.

&&

.MARINE...
SAIPAN BUOY SHOWED A RAPID RISE IN SEAS OVERNIGHT AS THE NORTH-
NORTHEAST SWELL BUILT IN SAIPAN WATERS. SWELL HAS REACHED GUAM AND
HAS BEEN SLIGHTLY LARGER THAN WW3 MODEL OUTPUT WITH SAIPAN BUOY
INDICATING A 7-FOOT 12 SECOND NNE SWELL. THUS...A HIGH SURF ADVISORY
WAS ISSUED THIS MORNING WITH SURF HEIGHTS OF 8 TO 9 FEET LIKELY
CONTINUING OVERNIGHT. SURF IS EXPECTED TO FALL SLIGHTLY THURSDAY BUT
A SECONDARY LONG-PERIOD SWELL FROM THE NORTHEAST WILL INCREASE
FRIDAY BRINGING SURF TO ADVISORY LEVELS ONCE AGAIN. SURF SHOULD FALL
BELOW ADVISORY LEVELS LATE SATURDAY NIGHT OR EARLY SUNDAY MORNING.

&&

.EASTERN MICRONESIA...
AN AREA OF SHOWERS AND THUNDERSTORMS PUSHED ACROSS POHNPEI TODAY.
SATELLITE IMAGERY SHOWED THAT THIS AREA WAS WEAKENING BUT LINGERING
SCATTERED SHOWERS ARE LIKELY FOR AT LEAST PART OF THE NIGHT. WHILE
THE CHANCE OF THUNDERSTORMS IS LOW...A FEW MAY OCCUR SO ADDED A
SLIGHT CHANCE OF THUNDERSTORMS TO THE POHNPEI FORECAST FOR TONIGHT.
LOW-LEVEL CONVERGENCE WILL KEEP SKIES MOSTLY CLOUDY ACROSS POHNPEI
THROUGH SATURDAY.

A SURFACE TROUGH IS STRETCHED ACROSS THE MARSHALL ISLANDS. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS COULD BE FOUND SOUTH OF MAJURO
THIS AFTERNOON. WHILE THE BULK OF THE ACTIVITY WILL REMAIN SOUTH OF
MAJURO...IT WILL PRODUCE ISOLATED SHOWERS AND A SLIGHT CHANCE OF
THUNDERSTORMS TONIGHT THROUGH THURSDAY NIGHT.

THIS SAME TROUGH WILL MOVE WEST AND CAUSE WINDS TO BECOME NORTHEAST
AT KOSRAE THURSDAY NIGHT. IT WILL BRING SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS TO KOSRAE FRIDAY AND FRIDAY NIGHT. HIGH
PRESSURE WILL BUILD ACROSS KOSRAE AND MAJURO SATURDAY AND SUNDAY.

&&

.WESTERN MICRONESIA...
A SURFACE TROUGH OF LOW PRESSURE CONTINUES TO STRETCH ACROSS THE
WESTERN HALF OF MICRONESIA. THE TROUGH AXIS WAS NORTH OF 10N.
CONVERGENCE SOUTH OF THE TROUGH BROUGHT SOME PATCHES OF SHOWERS AND
THUNDERSTORMS ACROSS PALAU AND YAP THIS AFTERNOON. WHILE ISOLATED
SHOWERS ARE EXPECTED TO BE THE PREDOMINANT COVERAGE... ISOLATED
THUNDERSTORMS ARE ALSO POSSIBLE ACROSS PALAU TONIGHT.

A CIRCULATION COULD BE FOUND ALONG THE TROUGH JUST SOUTH OF GUAM
THIS AFTERNOON. THIS TROUGH WILL PUSH SOUTHWEST TOWARD YAP. MODELS
SHOW IT WILL PASS CLOSE TO YAP ON THURSDAY. AT THIS TIME THE MODELS
KEEP THE WEATHER RATHER BENIGN NEAR THE CENTER OF THE CIRCULATION.
THE CIRCULATION LOOKS AS THOUGH IT WILL PUSH THE SHOWERS NOW NEAR
PALAU AND YAP FURTHER SOUTHWARD AS IT MOVES OVER YAP. THE
CIRCULATION WILL MOVE WEST TO 130E BY FRIDAY. IN THE WAKE OF THE
CIRCULATION...EAST TRADE WINDS WILL BUILD ACROSS PALAU AND YAP BY
THE END OF THE WEEK.

THE SOUTHWEST WINDS AT CHUUK TODAY WILL GIVE WAY TO NORTHEAST TRADE
WINDS THURSDAY NIGHT. FAIR WEATHER WILL PREVAIL ACROSS CHUUK THROUGH
THURSDAY NIGHT. MODELS SHOW A CIRCULATION DEVELOPING SOUTH OF CHUUK
THIS WEEKEND. WHILE MOST OF THE ACTIVITY WILL REMAIN SOUTH OF
CHUUK...MOSTLY CLOUDY SKIES AND A SLIGHT CHANCE THUNDERSTORMS WILL
PREVAIL FROM FRIDAY THROUGH MONDAY.

STRONG WINDS ASSOCIATED WITH A STORM SYSTEM IN THE NORTH PACIFIC
PRODUCED SWELLS THAT HAVE GENERATED HIGH SURF ACROSS THE MARIANAS
THIS AFTERNOON. MODELS SHOW LONG-PERIOD SWELLS PUSHING ACROSS YAP
AND PALAU SOMETIME THIS WEEKEND. AT THIS TIME...THESE SWELLS DO NOT
APPEAR TO BE HIGH ENOUGH TO GENERATE HAZARDOUS SURF AT THESE TWO
LOCATIONS. THIS SHOULD BE WATCHED AS THESE SWELLS WERE NOT EXPECTED
TO PRODUCE HAZARDOUS SURF ACROSS THE MARIANAS. AT ANY RATE EVEN IF
HAZARDOUS SURF DOES NOT OCCUR...THESE LONG PERIOD SWELLS...UP TO 14
SECONDS...MAY STILL PRODUCE A HIGHER RIP CURRENT RISK THIS WEEKEND.
THE SAME WAVE MODELS ALSO SHOW THE SURF POSSIBLY APPROACHING
HAZARDOUS AT CHUUK LATE FRIDAY NIGHT. AGAIN...EVEN IF SURF DOES NOT
REACH HAZARDOUS LEVELS...THE RIP CURRENT RISK WOULD LIKELY INCREASE.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF ADVISORY UNTIL 4 PM CHST SUNDAY FOR GUZ001>004.

MARIANAS WATERS...NONE.
&&

$$

WILLIAMS/ZIOBRO







000
FXPQ60 PGUM 220627
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
427 PM CHST WED OCT 22 2014

.MARIANAS SYNOPSIS...
A SHEAR LINE ALONG WITH A DEFINED LINE OF SHOWERS AND
THUNDERSTORMS ARE PRESENT ACROSS THE FAR NORTHERN MARIANAS. A
WEAK CIRCULATION AND TROUGH ARE FOUND SOUTHEAST OF GUAM. SHOWERS
ASSOCIATED WITH THE TROUGH ARE APPROACHING EASTERN MARIANAS
COASTAL WATERS.

&&

.DISCUSSION...
THE CIRCULATION AND SURFACE TROUGH SOUTHEAST OF THE MARIANAS WILL
SLOWLY PUSH NORTHWARD...THEN WESTWARD THROUGH THURSDAY. WINDS
WILL VEER FROM THE EAST TO THE THURSDAY AND INTRODUCE DEEPER
TROPICAL MOISTURE TO THE MARIANAS. ADJUSTED SKY COVER TO MOSTLY
CLOUDY THURSDAY THROUGH FRIDAY NIGHT TO ACCOUNT FOR THE PASSAGE
OF THE CIRCULATION/TROUGH. SATELLITE AND RADAR IMAGERY INDICATE
ONLY ISOLATED SHOWER COVERAGE AT THE MOMENT. GFS AND NAVGEM ARE
STILL THE DRIER NWP SOLUTIONS WHILE THE ECMWF HOLDS OFF ON
INCREASED SHOWERS UNTIL FRIDAY NIGHT. UNCERTAINTY EXISTS
REGARDING THIS SYSTEM SINCE IT A SMALL FEATURE AND PROBABLY IS
NOT BEING HANDLED WELL BY MODELS. ONCOMING SHIFT SHOULD ASSESS IF
AN UPDATE IS NEEDED IF SHOWERS INCREASE FASTER THAN EXPECTED. FOR
NOW...ONLY ISOLATED SHOWERS ARE EXPECTED THU THROUGH FRI NIGHT
OWING TO AT LEAST SOME CONSISTENCY TO THE GFS AND NAVGEM RUNS
OVER THE LAST 24 HOURS. MODEL AGREEMENT BECOMES POOR AFTER THE
PASSAGE OF THE CIRCULATION/TROUGH OVER THE SOUTHERN MARIANAS WITH
ECMWF KEEPING THE AREA UNDER AMPLE MOISTURE AND WIDESPREAD SHOWER
ACTIVITY WHILE GFS AND NAVGEM CONTINUE TO BE THE LESS AGGRESSIVE
FORECAST...EVEN IN THE LONG TERM. THE FORECAST FOR NEXT WEEK IS
LARGELY PERSISTENCE WITH A DRY TRADE-WIND PATTERN EMERGING. A FEW
MORE MODEL RUNS WILL BE NEEDED BEFORE A CONSENSUS CAN BE MADE
REGARDING ANY CHANGES IN THE FORECAST FOR NEXT WEEK.

&&

.MARINE...
SAIPAN BUOY SHOWED A RAPID RISE IN SEAS OVERNIGHT AS THE NORTH-
NORTHEAST SWELL BUILT IN SAIPAN WATERS. SWELL HAS REACHED GUAM
AND HAS BEEN SLIGHTLY LARGER THAN WW3 OUTPUT WITH SAIPAN BUOY
INDICATING A 7 FT 12 SECOND NNE SWELL. THUS...A HIGH SURF
ADVISORY WAS ISSUED THIS MORNING WITH SURF HEIGHTS OF 8 TO 9 FEET
LIKELY CONTINUING OVERNIGHT. SURF IS EXPECTED TO FALL SLIGHTLY
THURSDAY BUT A SECONDARY LONG-PERIOD SWELL FROM THE NORTHEAST
WILL INCREASE FRIDAY BRINGING SURF TO ADVISORY LEVELS ONCE AGAIN.
SURF SHOULD FALL BELOW ADVISORY LEVELS LATE SATURDAY NIGHT OR
EARLY SUNDAY MORNING.

&&

.EASTERN MICRONESIA...
AN AREA OF SHOWERS AND THUNDERSTORMS PUSHED ACROSS POHNPEI TODAY.
SATELLITE IMAGERY SHOWED THAT THIS AREA WAS WEAKENING BUT
LINGERING SCATTERED SHOWERS ARE LIKELY FOR AT LEAST PART OF THE
NIGHT. WHILE THE CHANCE OF THUNDERSTORMS IS LOW A FEW MAY OCCUR
SO ADDED A SLIGHT CHANCE OF THUNDERSTORMS TO TONIGHT POHNPEI
FORECAST. LOW- LEVEL CONVERGENCE WILL KEEP SKIES MOSTLY CLOUDY
ACROSS POHNPEI THROUGH SATURDAY.

A SURFACE TROUGH IS STRETCHED ACROSS THE MARSHALL ISLANDS.
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS COULD BE FOUND SOUTH
OF MAJURO THIS AFTERNOON. WHILE THE BULK OF THE ACTIVITY WILL
REMAIN SOUTH OF MAJURO IT WILL PRODUCE ISOLATED SHOWERS AND A
SLIGHT CHANCE OF THUNDERSTORMS TONIGHT THROUGH THURSDAY NIGHT.

THIS SAME TROUGH WILL MOVE EAST AND CAUSE WINDS TO BECOME NORTHEAST
AT KOSRAE THURSDAY NIGHT. IT WILL BRING SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS TO KOSRAE FRIDAY AND FRIDAY NIGHT. HIGH
PRESSURE WILL BUILD ACROSS KOSRAE AND MAJURO SATURDAY AND SUNDAY.

&&

.WESTERN MICRONESIA...
A SURFACE TROUGH OF LOW PRESSURE CONTINUES TO STRETCH ACROSS THE
WESTERN HALF OF MICRONESIA. THE TROUGH AXIS WAS NORTH OF 10N.
CONVERGENCE SOUTH OF THE TROUGH BROUGHT A SOME PATCHES OF SHOWERS
AND THUNDERSTORMS ACROSS PALAU AND YAP THIS AFTERNOON. WHILE
ISOLATED SHOWERS ARE EXPECTED TO BE THE PREDOMINANT COVERAGE A
ISOLATED THUNDERSTORMS IS POSSIBLE ACROSS PALAU TONIGHT.

A CIRCULATION COULD BE FOUND ON THE TROUGH JUST SOUTH OF GUAM
THIS AFTERNOON. THIS TROUGH WILL PUSH SOUTHWEST TOWARD YAP.
MODELS SHOW IT CLOSE TO YAP ON THURSDAY. AT THIS TIME THE MODELS
KEEP THE WEATHER RATHER BENIGN NEAR THE CENTER OF THE
CIRCULATION. THE CIRCULATION LOOKS AS THOUGH IT WILL PUSH THE
SHOWERS NOW NEAR PALAU AND YAP FURTHER SOUTHWARD AS IT MOVES OVER
YAP. THE CIRCULATION WILL MOVE WEST TO 130E BY FRIDAY. IN THE
WAKE OF THE CIRCULATION EAST TRADE WINDS WILL BUILD ACROSS PALAU
AND YAP BY THE END OF THE WEEK.

THE SOUTHWEST WINDS AT CHUUK TODAY WILL GIVE WAY TO NORTHEAST
TRADE WINDS THURSDAY NIGHT. FAIR WEATHER WILL PREVAIL ACROSS
CHUUK THROUGH THURSDAY NIGHT. MODELS SHOW A CIRCULATION
DEVELOPING SOUTH OF CHUUK THIS WEEKEND. WHILE MOST OF THE
ACTIVITY WILL REMAIN SOUTH OF CHUUK...MOSTLY CLOUDY SKIES AND A
SLIGHT CHANCE THUNDERSTORMS WILL PREVAIL FRIDAY THROUGH MONDAY.

STRONG WINDS ASSOCIATED WITH A STORM SYSTEM IN THE NORTH PACIFIC
PRODUCED SWELLS THAT HAVE GENERATED HIGH SURF ACROSS THE MARIANAS
THIS AFTERNOON. MODELS SHOW LONG-PERIOD SWELL PUSHING ACROSS YAP
AND PALAU SOMETIME THIS WEEKEND. AT THIS TIME...THESE SWELL DO NOT
APPEAR TO BE HIGH ENOUGH TO GENERATE HAZARDOUS SURF AT THESE TWO
LOCATIONS. THIS SHOULD BE WATCHED AS THIS SWELL WAS NOT EXPECTED
TO PRODUCE HAZARDOUS SURF ACROSS THE MARIANAS. AT ANY RATE EVEN IF
HAZARDOUS SURF DOES NOT OCCUR THE LONG PERIOD SWELL...UP TO 14
SECONDS...MAY STILL PRODUCE A HIGHER RIP CURRENT RISK THIS
WEEKEND. THE SAME WAVE MODELS ALSO SHOW THE SURF POSSIBLY
APPROACHING HAZARDOUS AT CHUUK LATE FRIDAY NIGHT. AGAIN...EVEN IF
SURF DID NOT REACH HAZARDOUS THE RIP CURRENT RISK WOULD LIKELY
INCREASE.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF ADVISORY UNTIL 4 PM CHST SUNDAY FOR GUZ001>004.

MARIANAS WATERS...NONE.
&&

$$

WILLIAMS/ZIOBRO







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