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000
agpn40 kwnm 152115
mimpac
marine weather discussion for n pacific ocean
nws ocean prediction center washington dc
230 pm pdt sun 15 mar 2009
. forecast discussion: major features/winds/seas/significant
. weather for the north pacific n of 30n and e of 150w.
short term thru tue ngt ... 15z 12. 5km quikscat just w of pz5/nrn
pz6 wtrs indicated a few storm force retrievals s of storm cntr
currently about 180 nm w of cape flattery. system has potent sat
signture with occluded bndry appearing to have wrapped all the
way to se of center. qscat also had w to nw gales extnding s to
about 43n ... or w of cape blanco. given 12z guidance ... not
planning on signfncnt changes to near term fcst. will allow
warnings over pz5 wtrs to expire tngt as strong low pres moves
inland over vancouver island. over next cple days series of
shrtwvs will pass e twrd nrn oregon/wa and vancouver
island ... generally supporting mdt sw flow over pz5 wtrs mon thru
tue. models then bring sharper shrt wv twrd canadian coast...
queen charlottes and n of vancouver island early wed which shud
support a weakening cold frnt thru wa/or ofshr wed into thu. 12z
guidance in pretty good agreement with timing of frnt and have
mdt fcst confdc in brief period of ofshr gales over wa wtrs tue
ngt into early wed. fcst confdc a bit hier due to 12z ecmwf
whose winds are typically underdone over oceans as shown in
global study by chelton/frielich from oregon st univ where
guidance was compared to quikscat ... with ecmwf wind speeds
biased low relative to gfs as well. and with 12z ecmwf
indicating 30 to 35 kt ofshr extnding from near cape shoalwater
to n of vancouver island. so will maintain the marginal gales
over wa wtrs as in prev pz5 fcst. meanwhile for ca ofshr wtrs
cold frnt assoc with above mentioned low pres has moved into nrn
ca wtrs and shud stall and slowly weaken over next 36hrs. with
high pres ridge dominating off cntrl ca and typical nw 20 to 25
kt invof pt concption.
med range wed thru fri ... models diverge considerably over the e
pacific at days 4/5. first for thu 12z ecmwf/canadian bring lead
shrtwv twrd vancouver island late wed/thu and dvlp assoc sfc low
with 25 or 30 kt winds over pz5 wtrs. 12z gfs/ukmet largely
devoid of this feature with ukmet indicating some sfc trofiness.
will compromise between solutions and go with 15 to 20 kt over
both pz5 zones thu. by day5 fri ... with the exception of the 12z
ecmwf which is less progrssv with system amplfiying se out of
bering ... models bring mean upper trof psn just e of 140w. 12z
gefs/naefs means also support this solution. ecmwf ensmbls
unavailable since 14/12z. 12z canadian does apper too amplified.
generally will introduce incresing trnds with winds/seas n of pt
st george fri ... which is consistent with 12z gfs/canadian. over
pz6 wtrs ... high pres ridge conts to dominate ... with 25 kt
persisting invof pt conception into fri.
not planning on making signfcnt adjustments to 12z enp wavewatch
iii output thru fcst period. hiest res multigrid wavewatch iii
seems to have good handle on this aftrnoons arrival of hiest
seas to wa/or coasts.
. warnings/forecast confidence ... warnings are preliminary and are
subject to change. any changes will be coordinated through awips
12 planet chat or by telephone:
. pz5 washington/oregon waters...
. cape flattery to cape lookout ... storm into tngt ... hi confdc.
gale late tue ngt into wed ... mdt confdc.
. cape lookout to point st george ... gale into tngt ... hi confdc.
. pz6 california waters...
. pt st george to pt arena ... none.
. pt arena to pt conception ... none.
. pt conception to guadalupe island ... none.
. forecaster clark. ocean forecast branch.