Alert archive / Guam / High Surf Advisories in 2012

High Surf Advisory 18, NWS Guam

December 14, 2012

NWS Guam issued this high surf advisory at Dec 14, 2012, 12:00 AM CST. It took effect at Dec 14, 2012, 2:00 AM CST. It was in force for 20 hr.

The area

The counties it named.

The facts

Issued: Dec 14, 2012, 12:00 AM CST (06:00 UTC)
In effect from: Dec 14, 2012, 2:00 AM CST
Expired: Dec 14, 2012, 10:01 PM CST
In force: 20 hr
Issued by: NWS Guam

What forecasters said that day

The local office's own words before this high surf advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Guam wrote its last area forecast discussion before this high surf advisory went out at Dec 13, 11:01 PM CST, 59 minutes earlier.

Area forecast discussion, Dec 13, 11:01 PM CST, 59 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
301 PM CHST FRI DEC 14 2012

.SYNOPSIS...
SATELLITE SHOWS THE MARIANAS IN A DRY SLOT BETWEEN AN OLD SHEAR
LINE JUST SOUTH OF GUAM AND A NEWER SHEAR LINE JUST NORTH OF
SAIPAN DRIFTING SOUTHWARD. FRESH TO STRONG TRADES ARE KICKING UP
HAZARDOUS SEAS ACROSS THE MARIANAS WATERS.

&&

.DISCUSSION...
LATEST MODELS SHOW LITTLE CHANGE FROM PREVIOUS RUNS...WITH FRESH
TO STRONG TRADES PEAKING TONIGHT AND SATURDAY AT AROUND 25 KT.
SHOWER COVERAGE REMAINS UNCERTAIN...AS THE SHEAR LINES SEEM TO
REMAIN JUST NORTH AND SOUTH OF THE ISLANDS. BEST CHANCE FOR
SCATTERED COVERAGE SEEMS TO BE SATURDAY NIGHT AND SUNDAY WHEN GFS
AND ECMWF HAVE THE DEEPEST MOISTURE...BUT PLENTY OF UNCERTAINTY.

&&

.MARINE/SURF...
WINDS SET TO PEAK AT 25 KT TONIGHT AND SATURDAY...THEN BEGIN A
LONG SLOW DECLINE THE NEXT FEW DAYS. WINDS SHOULD DROP BELOW SMALL
CRAFT LEVELS ON SUNDAY...BUT SEAS WILL LIKELY REMAIN AT 10 FT
THROUGH SUNDAY NIGHT. THE COMBO OF EAST SWELL AND WIND WAVES WILL
PUSH SURF UP TO 12-13 FEET THE NEXT COUPLE OF DAYS ALONG EAST
FACING REEFS...AND UP TO 9 FEET ALONG NORTH FACING REEFS...SO HIGH
SURF ADVISORY ISSUED WITH THIS FORECAST PACKAGE.

&&

.EASTERN MICRONESIA...
A DRY TRADE-WIND PATTERN DOMINATES AND MAINLY ISOLATED SHOWERS ARE
EXPECTED IN THE COMING DAYS. GFS MODEL INDICATES SOME MID TO UPPER
LEVEL MOISTURE COULD GRADUALLY MOVE INTO THE AREA BY EARLY NEXT
WEEK...BUT MAINLY FOR MORE SOUTHERN LOCATIONS SUCH AS KOSRAE...SO
CHANCES FOR THUNDERSTORMS AT POHNPEI AND MAJURO HAVE DIMINISHED.

&&

.WESTERN MICRONESIA...
A SURFACE TROUGH JUST WEST OF CHUUK IS TRIGGERING SCATTERED SHOWERS
AND A SHEAR-LINE FRAGMENT NEAR YAP IS ALSO PRODUCING SHOWERS. MODELS
INDICATE THE TROUGH WILL MOVE WESTWARD TO PALAU THIS WEEKEND WHILE
THE SHEAR LINE REMAINS STRETCHED FROM NEAR GUAM SOUTHWESTWARD TO THE
VICINITY OF YAP. OTHERWISE...MODERATE TO OCCASIONALLY STRONG TRADE
WINDS ARE EXPECTED TO CONTINUE FOR THIS AREA.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF ADVISORY FROM 6 PM THIS EVENING TO 6 PM CHST SUNDAY
     FOR GUZ001>004.

MARIANAS WATERS...SMALL CRAFT ADVISORY UNTIL 6 PM CHST MONDAY FOR
     PMZ151>154.

&&

MIDDLEBROOKE/SIMPSON

The office that day

Everything else NWS Guam issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 14, 2:10 PM CST	High Surf Warning	GUM		28 hr
Dec 14, 3:10 PM CST	High Surf Advisory	GUM		51 hr

Nearby

High Surf Advisories in Guam, 2012 Every high surf advisory in 2012

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text.