Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Medford or
412 am PST Monday Dec 22 2014
Discussion...rivers across the region have reached their crests
after the generous rainfall that we recieved over the past several
days. Showers continue to diminish with 700mb onshore flow through
the day as an upper level ridge builds over the region. These
showers continue to diminish further into Tuesday as the 700mb
flow diminishes. The upper level low brings clearing with morning
fog likely in the west side valleys. The next system moves into
the region Wednesday on the nose of an 120kt jet. With the strong
southerly flow snow levels start very high...but as the upper low
digs into northern California a cold air mass moves in towards
the tail end of the system. By 00z on the 25th the 0 c isotherm
drapes roughly against the Cascades with the NAM and the GFS
indicating up to a half inch of precipitation over the much of the west
side before the precipitation tapers off as the cold air mass slips over
to the east side. Currently snow levels looks to drop to a little
below 2500 feet by early Christmas morning...but the bulk of the
precipitation should be over with only very light amounts on the I-5
passes by Christmas morning. Sven
Aviation...for the 22/06z taf cycle...areas of light rain over the
region will gradually wind down tonight. Skies are not expected to
clear much but low clouds and fog with IFR ceilings is expected at the
terminals overnight. East side locations may also see similar
conditions develop late tonight and Monday morning. Mountains will
remain obscured through the night. Skies should finally break up
late Monday morning or early afternoon. Btl/Wright
Marine...updated 900 PM PST sun Dec 21 2014... weak high pressure
will remain over the waters through Tuesday resulting in relatively
light and variable winds. However... moderate west swell will
continue. A cold front will bring a period of strong winds and steep
seas to the waters Christmas evening into Christmas day.
or...Flood Watch until 7 am PST this morning for orz021-615.
Flood Watch until 7 am PST this morning for orz023-619-620.
Wind Advisory until noon PST today for orz030-031-624-625.
Flood Watch until 7 am PST this morning for orz025-616-617-623.
California...Wind Advisory until noon PST today for caz085-285.
Pacific coastal waters...Small Craft Advisory for hazardous seas until 10 am PST Thursday