Subject: Western Pacific: Synoptic Discussion For The Marianas

From: LDM Weather <[email-masked]>
Date: Mon, 22 Nov 2010 00:06:29 -0600

257 
FXPQ60 PGUM 220606
AFDPQ 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
406 PM CHST MON NOV 22 2010

.SYNOPSIS...
FORECAST ZONES REMAIN BENEATH DEEP LAYER RIDGING. RADAR SCAN IS
VIRTUALLY DEVOID OF SHOWERS AT THE MOMENT. VISIBLE SATELLITE
IMAGERY AND GFS TIME HEIGHT CROSS SECTION BOTH SUGGEST SLIGHTLY
DEEPER MOISTURE SHOULD BE ARRIVING LATER THIS EVENING SO WILL
MAINTAIN TRANSITION FROM SLIGHT CHANCE TO ISOLATED POPS DURING
THIS TIME FRAME. NEXT POTENTIAL WEATHER MAKER IS THE INVERTED
SURFACE TROUGH/TRADE-WIND DISTURBANCE MOVING FROM POHNPEI TOWARD
CHUUK.

&&

.DISCUSSION...
NO CHANGES TO FORECAST REASONING. GFS STILL APPEARS TO BE THE
MOST AGGRESSIVE MODEL IN BRINGING QPF THROUGH THE FORECAST ZONES
ON WEDNESDAY NIGHT AND THURSDAY...WITH OTHER MODELS BEING MUCH
LESS BULLISH ON QPF. GFS TIMING HAS NOT CHANGED MUCH DURING THE
PAST COUPLE OF DAYS. LATEST RUN SUGGESTS SCATTERED SHOWERS COULD
AFFECT THE GUAM AND ROTA FORECAST ZONES AS THE TROUGH PASSES
THROUGH. WILL HOLD OFF ON ADDING SCATTERED SHOWERS TO THE
FORECAST UNTIL THE DISTURBANCE GETS CLOSER AND MODEL SOLUTIONS
CONVERGE. REMAINDER OF THE FORECAST LOOKS RELATIVELY DRY WITH A
TRADE-WIND REGIME PREDOMINATING.

&&

.MARINE...
TWEAKED NEAR TERM MARINE SWELL GRIDS BASED UPON RECENT OBS FROM
THE IPAN BUOY. IPAN BUOY IS COMING IN WITH A DOMINANT SWELL FROM
050 DEGREES BETWEEN 3 AND 4 FEET. WIND WAVES WERE EVIDENT FROM
130 DEGREES WITH A 7 SECOND PERIOD. LONG TERM MARINE SWELL GRIDS
REQUIRED MINIMAL ADJUSTMENTS. STILL EXPECT HIGHEST SURF TO
CONTINUE ON NORTH AND EAST FACING REEFS FOR AT LEAST THE NEXT
SEVERAL DAYS. LITTLE DAY TO DAY CHANGE SHOULD OCCUR AS SURF
REMAINS A MODERATE RIP CURRENT RISK LEVELS.

&&

.EASTERN MICRONESIA...
MAJURO IS BEGINNING TO DRY OUT AS A TRADE-WIND DISTURBANCE MOVES
FARTHER WEST. SATELLITE IMAGERY SHOWS KOSRAE TO BE SITTING JUST
ON THE SOUTHERN EDGE OF THE CONVECTION ASSOCIATED WITH THE
DISTURBANCE. MODEL DATA SUGGESTS THAT ISOLATED SHOWERS WILL BE
THE NORM OVER KOSRAE FOR TONIGHT AND TOMORROW. HOWEVER...A SHORT
PERIOD OF SCATTERED SHOWERS IS NOT TOTALLY OUT OF THE QUESTION.
IF CONVECTION DEVELOPS FARTHER SOUTH...A FORECAST UPDATE MAY BE
REQUIRED. SHOWERS WILL DEVELOP OVER POHNPEI TONIGHT. THEY SHOULD
DISSIPATE AROUND MIDDAY TOMORROW AS THE DISTURBANCE CONTINUES
WESTWARD. WAVE WATCH 3 MODEL INDICATES INCREASED SEA HEIGHTS BY
THE WEEKEND IN RESPONSE TO A STRONG MID LATITUDE LOW CENTERED
WELL NORTHWEST OF WAKE ISLAND. HIGH SURF IS NOT EXPECTED AT THIS
TIME SINCE THE SWELL COMPONENTS WILL BE DIVIDED BETWEEN THE NORTH
AND EAST.

&&

.WESTERN MICRONESIA...
A SURFACE TROUGH NEAR POHNPEI WILL REACH CHUUK EARLY TUESDAY
MORNING. MODEL CONSENSUS KEEPS THE ASSOCIATED SHOWERS JUST NORTH
OF WENO ISLAND. FOR NOW THE TROUGH IS ONLY EXPECTED TO SHIFT
WINDS FROM NORTHEAST TO EAST AND INCREASE CLOUDS THROUGH
WEDNESDAY NIGHT. ANOTHER TROUGH EAST OF YAP IS EXPECTED TO REMAIN
CONVECTIVELY QUIET AS IT PASSES YAP AND KOROR TUESDAY. SATELLITE
IMAGERY SHOWS A SMALL CLUSTER OF CONVECTION OVER KOROR AT THE
MOMENT. HAVE ADDED SCATTERED SHOWERS AND A SLIGHT CHANCE OF
THUNDERSTORMS FOR THIS EVENING...BUT THEN CONDITIONS SHOULD
IMPROVE AROUND SUNSET. SIMILAR TO POHNPEI...WAVE WATCH 3 MODEL
INDICATES INCREASED SEA HEIGHTS LATER THIS WEEK ON CHUUK...BUT A
HIGH SURF EVENT IS NOT EXPECTED SINCE SWELL COMPONENTS WILL ALSO
BE DIVIDED BETWEEN THE NORTH AND EAST.

&&

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

$$

MCELROY/W. AYDLETT

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