Red Flag Warning 4, NWS Guam

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
743 AM CHST WED APR 20 2016

.SYNOPSIS...
PGUA DOPPLER WEATHER RADAR SHOWS ISOLATED SHOWERS MOVING THROUGH
THE MARIANAS WATERS. THE VAD WIND PROFILE REVEALS EAST-NORTHEAST
WINDS OF 8 TO 12 KNOTS AT 1000 FEET WHICH INCREASE TO BETWEEN 18
AND 26 KNOTS FROM TWO THOUSAND TO TEN THOUSAND FEET.

&&

.DISCUSSION...
TRADE-WIND SURGE SHOULD START TO WEAKEN TONIGHT AS PREVIOUSLY
FORECAST. ONLY SUBSTANTIVE CHANGE WAS DURING THE UPCOMING TRADE
WIND DISTURBANCE AROUND THE WEEKEND. WENT AHEAD AND MADE THE
ISOLATED SHOWERS MODERATE VERSUS LIGHT AS THIS DISTURBANCE PASSES.
OTHERWISE JUST REFRESHED THE WAVE GRIDS. VERY LITTLE CHANGE IN
FORECAST PHILOSOPHY. RAINFALL ACCUMULATIONS ARE STILL EXPECTED TO
BE UNDERWHELMING. JUST HOW UNDERWHELMING WILL BE THE QUESTION.
GFS40 PREDICTS ABOUT 0.60 INCHES... WHILE THE ECMWF-HIRES PROGS
ONLY ABOUT 0.25 INCHES. IF THE GFS40 VERIFIES...THE KEETCH-BYRAM
DROUGHT INDEX...CURRENTLY AT 762...COULD TAKE A HIT OVER THE
WEEKEND.

&&

.MARINE...
ENHANCED WINDS ALOFT WILL ALLOW FREQUENT GUSTS TO 25 KNOTS LATER
THIS MORNING AND THIS AFTERNOON. IPAN BUOY SHOWS SEAS JUST BARELY
UNDER 10 FEET...SO CHANGED WORDING OF SMALL CRAFT ADVISORY FROM 10
FEET NORTHEAST OF SAIPAN TO 10 FEET EAST OF THE ISLANDS. LITTLE
CHANGE IN OVERALL PHILOSOPHY THOUGH...WINDS AND SEAS ARE STILL
EXPECTED TO START DIMINISHING TONIGHT.

&&

.EASTERN MICRONESIA...
SHOWERS ASSOCIATED WITH A TRADE-WIND DISTURBANCE CONTINUE TO REMAIN
SOUTHEAST OF THE MARSHALL ISLANDS AND OVER BUTARITARI AND TARAWA
ATOLLS. UPPER-LEVEL CLOUD DEBRIS FROM THIS CONVECTION IS MAKING ITS
WAY NORTHWARD OVER THE RMI BUT SHOWERS WILL REMAIN LIMITED FOR THE
NEXT FEW DAYS WITH MOST ACTIVE WEATHER STAYING TO THE SOUTH.
SATELLITE SHOWS RELATIVELY CLEAR SKIES OVER MUCH OF KOSRAE STATE.
HOWEVER...MODEL GUIDANCE SUGGESTS CLOUDS AND SHOWERS WILL INCREASE
LATE TODAY AND TONIGHT OVER KOSRAE AS CONVECTION ASSOCIATED WITH THE
TRADE-WIND CONVERGENCE ZONE BUILDS OVER THE STATE. A BAND OF
SCATTERED SHOWERS IS EXPECTED TO PERSIST OVER POHNPEI FOR THE NEXT
COUPLE OF DAYS OR SO BEFORE SHIFTING SOUTHWARD AS THE WEEKEND
APPROACHES.

SWELL AND WIND WAVES WILL DIMINISH FURTHER ACROSS KOSRAE STATE AS
TRADE WINDS HAVE DECREASED ACROSS THE REGION. THIS WILL ALLOW SURF
ON EAST FACING SHORES OF KOSRAE TO FALL BELOW HAZARDOUS LEVELS THIS
AFTERNOON.

&&

.WESTERN MICRONESIA...
SHOWERS WITHIN THE TRADE-WIND CONVERGENCE ZONE EXTEND WESTWARD INTO
CHUUK AND YAP STATES AND THE REPUBLIC OF PALAU. THIS ACTIVE
WEATHER PATTERN WILL CONTINUE AT LEAST FOR THE NEXT COUPLE OF DAYS
FOR CHUUK AND KOROR WITH PERIODS OF SCATTERED SHOWERS AFFECTING
THESE LOCATIONS. MODELS ARE IN GOOD AGREEMENT IN KEEPING MANY OF
THE SHOWERS SOUTH OF YAP THROUGH THURSDAY NIGHT BUT BRING WETTER
WEATHER BACK OVER YAP FRIDAY AND SATURDAY. THIS WOULD BRING SHORT
TERM RELIEF FROM THE SEVERE TO EXCEPTIONAL DROUGHT TO MANY
LOCATIONS WITHIN WESTERN MICRONESIA WITH THE EXCEPTION OF SONSOROL
SOUTHWEST OF PALAU.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...FIRE WEATHER WATCH UNTIL 6 PM CHST THIS EVENING FOR GUZ001.

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

&&

STANKO/WILLIAMS