Area Forecast Discussion
Issued by NWS Pago Pago

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118
FXZS60 NSTU 200048
AFDPPG

AREA FORECAST DISCUSSION FOR AMERICAN SAMOA AND INDEPENDENT SAMOA
NATIONAL WEATHER SERVICE PAGO PAGO AS
148 PM SST SUN FEB 19 2017

.SHORT TERM...
.TONIGHT THROUGH TUESDAY NIGHT...GFS MODEL HAS A BETTER HANDLE ON
THE LATEST SITUATION COMPARING TO WRF AND UKMET MODELS. STRONG
LOW-LEVEL CONVERGENCE ALONG THE MONSOONAL TROUGH AXIS WILL INHERIT
STRONG GUSTY WINDS...HEAVY RAINFALL AND ISOLATED TSTMS TONIGHT. AN
EMERGING CIRCULATION ALONG THE LEADING EDGE OF THE EXISTING MONSOONAL
TROUGH WILL STEER THIS TROUGH AXIS SSE AND AWAY FROM THE REGION
MONDAY NIGHT. THANKS TO A SURFACE TO MID-LEVEL RIDGE UPSTREAM THAT
WILL CONTINUE TO MAINTAIN ITS POSITION THUS ALLOWING DRY AND
FAVORABLE CONDITIONS TO SETTLE OVER THE AREA AT THE LATTER PART OF
THE SHORT TERM. AS A RESULT...ANTICIPATE WET WEATHER CONDITIONS
TO LET UP BEFORE MONDAY EVENING...AND STRONG GUSTY WINDS TO
DIMINISH AT LEAST BY TUESDAY EVENING IF NOT SOONER.

.LONG TERM...
.WEDNESDAY THROUGH SUNDAY...A BOLD SURFACE RIDGE UPSTREAM WILL
CONTINUE TO PROVIDE DRY AND FAVORABLE WEATHER JUST NORTH OF THE
MAIN SAMOAN ISLES THROUGH THE LONG TERM. PERHAPS...AN ELONGATED NW
TO SE ORIENTED MONSOONAL TROUGH TO THE SOUTH WILL HAVE MINIMAL TO
NO IMPACT TO LOCAL WEATHER CONDITIONS UNLESS THIS TROUGH DECIDES
TO RELOCATE NEAR THE SAMOAN ISLANDS LATER DURING THE WEEK. THEREFORE...
ANTICIPATE ISOLATED TO SCATTERED SHOWERS AND MODERATE TO FRESH NW
WINDS ACROSS THE AREA.

&&

.MARINE...STRONG WINDS AND HIGHER GUSTS ASSOCIATED TO A MONSOONAL
TROUGH WILL GENERATE LOCALIZED SWELLS UP TO 9 FT THROUGH EARLY
MONDAY MORNING. THESE LARGE SEAS WILL EVENTUALLY SUBSIDE TO NEAR 5 TO
7 FT WEDNESDAY AFTERNOON AS THE TROUGH AXIS SLIDES SSE OF THE
SAMOAN WATERS. ISSUANCE OF ADVISORIES FOR HIGH SURFS AND SMALL
CRAFTS ARE MANDATORY TO REFLECT THE EFFECTS OF THE MONSOONAL TROUGH
OVER SEAS AND WINDS.

&&

.PPG WATCHES/WARNINGS/ADVISORIES...

.A WIND ADVISORY REMAINS IN EFFECT UNTIL TUESDAY NIGHT.
.A HIGH SURF ADVISORY REMAINS IN EFFECT UNTIL TUESDAY NIGHT.
.A SMALL CRAFT ADVISORY REMAINS IN EFFECT.
.A FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH MONDAY NIGHT.

&&

$$

CB









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