638
FNUS70 PGUM 192320
FWSGUM

Spot Forecast for SE-25-04...NMFS
National Weather Service Tiyan GU
920 AM ChST Sun Jul 20 2025

Forecast is based on forecast start time of 1000 ChST on July 20.
If conditions become unrepresentative...contact the National Weather
Service.

Please contact our office by email at nws.gum.operations@noaa.gov
if you have questions or concerns with this forecast.

.DISCUSSION...The Marianas remain under the influence of the Tropical
Upper-Tropospheric Trough (TUTT). The TUTT will maintain an unstable
atmosphere across the islands as it interacts with the monsoon
trough. This will result in numerous showers continuing across the
Marianas today, becoming scattered tonight into Monday. Isolated
thunderstorms will also continue for the next few days. For today,
gusty winds are likely with heavier showers and thunderstorms. Shower
coverage will continue to decrease Monday, with showers becoming
isolated by Tuesday.

.TODAY (SAIPAN)...

Sky/weather.........Cloudy (85-95 percent). Numerous locally heavy
showers and isolated thunderstorms.
Surface winds (kts).East to southeast winds 5 to 15 knots. Gusts to
25 kt near heavier showers and thunderstorms.
Wave heights........4 to 6 feet.

.TONIGHT (SAIPAN)...

Sky/weather.........Mostly cloudy (60-70 percent). Scattered
                    showers and isolated thunderstorms.
Surface winds (kts).Variable winds up to 5 knots.
Wave heights........3 to 5 feet.

.MONDAY (GUAM)...

Sky/weather.........Mostly cloudy (60-70 percent). Scattered showers
                    and isolated thunderstorms.
Surface winds (kts).Southeast winds 5 to 8 knots.
Wave heights........3 to 4 feet.

$$
Forecaster...KK
Requested by...Benjamin Richards
Type of request...MARINE
.TAG 2518279.0/GUM
.DELDT 07/20/25
.FormatterVersion 2.0.0
.EMAIL benjamin.richards@noaa.gov,eva.schemmel@noaa.gov,ops.sette@noaa.gov,co.sette@noaa.gov,nws.gum.operations@noaa.gov