Scientific Forecaster Discussion
Area forecast discussion
National Weather Service tiyan GU
848 am chst Monday may 4 2015
pgua WSR-88D shows isolated trade-wind showers moving through the
marianas waters. The outermost rain band of tropical storm noul
can be seen to the south and southwest of Guam waters. The VAD
wind profile reveals east winds of 10 to 22 knots through the
lowest 7 thousand feet of the air.
Drew in a mostly cloudy area to the southwest of Guam related to
the outer rain band of tropical storm noul. The effects of noul
on the marianas will be limited as it is already moving away. Once
these clouds pull away...some southwest swell will be all that
remains. This swell will gradually turn toward the west. The
silicon cyclone of the European model (ecmwf)-hires did persist...and it did move
to day 9. Additionally...the gfs40 is now joining it. This is
enough to make ME take notice...for now changed the last 3 days of
the grids to mostly cloudy. If this continues to persist through
additional model runs...more drastic forecast action might be
needed. Combined seas of 4 to 7 feet will continue all this week.
noul has been upgraded to a tropical storm. Tropical storm watches
remain in effect for Yap and ngulu. Tropical storm warnings are
now in effect for fais and ulithi. Noul is just starting to settle
into a somewhat better behaved track. It is now very close to fais
and the current forecast takes it very close to ulithi.
Models show another circulation starting to organize behind noul.
It is expected to take a few more days to develop. Both the Joint
Typhoon Warning Center and the National Weather Service Guam
forecast office will closely monitor this area.
Eastern micronesia... showers and thunderstorms are seen across the
region from just east of Pohnpei to south of Majuro. A monsoon
trough remains stretched across the region passing south of
Pohnpei...near Kosrae and to the south of Majuro. A weak
disturbance remains in place southwest of Pohnpei. Moderate to
fresh dry trades will promote a continuation of drier conditions
at Majuro this week. A much wetter scenario is still expected at
Kosrae and Pohnpei through the end of the week. Model guidance
maintains a weak and meandering circulation southwest of Pohnpei
at least through midweek. Scattered showers and isolated
thunderstorms will persist at Pohnpei and Kosrae while the trough
and circulation remain in the area. However...cannot rule out a
few periods of drier conditions between now and Friday.
Western micronesia... Chuuk...little change to the Chuuk
forecast. Forecast maintains isolated showers and thunderstorms
through the end of the week. A circulation southeast of Chuuk will
meander in place the next few days. Models keep much of the
moisture near the center and to the east of the circulation.
Yap...tropical storm noul (06w) is the main focus here at least
for the next 48 hours. A tropical storm watch remains in effect
for Yap and ngulu. A Tropical Storm Warning is now in effect for
fais and ulithi. Tropical storm noul is centered east of Yap and
just southeast of fais. Tropical storm noul will continue to
drift slowly northwest with a gradual turn toward the west.
Conditions will quickly deteriorate at Yap today with showers and
winds increasing overnight. Tropical storm force conditions are
possible by early tomorrow morning. Forecast in the near-term
ultimately depends on how quickly noul strengthens...and how fast
it tracks towards the northwest or west-northwest. Seas and surf will become
hazardous by tonight. More detailed information for Yap...ngulu...
ulithi and fais can be found in the hurricane local statement
issued by the National Weather Service under WMO header wtpq81
Koror...tropical storm noul is expected to pass north of Koror in
the next few days. Models still show fairly dry conditions there
as noul passes. Winds and seas will increase tonight and Tuesday
and surf could become hazardous on Tuesday along north-facing
reefs. Showers and thunderstorms are expected to remain confined
close to the center and north of Koror...but will have to watch
carefully as the track and forward motion has been slow and