NWS Medford, OR wrote its last area forecast discussion before the first event at Feb 9, 10:12 AM PST, 3 hours 18 minutes earlier.
Area forecast discussion, Feb 9, 10:12 AM PST, 3 hours 18 minutes before
Area Forecast Discussion
National Weather Service Medford OR
1012 AM PST Thu Feb 9 2017
.DISCUSSION...See the Aviation and Marine Discussions below.
&&
.AVIATION...09/18Z TAF CYCLE...LLWS will be an issue across the
forecast area at least through mid afternoon. An A319 aircraft
reported mod-sev turbulence between 8500-9500 feet over MFR at
1630Z.
MVFR will remain widespread along the coast with areas of
IFR/LIFR...mainly along the south coast near Gold Beach and
Brookings. Periods of moderate to heavy rainfall and strong, gusty
south winds will continue in those areas today. Winds will decrease
only slightly this evening as another system moves by to the north
and continues showers with a mix of MVFR and VFR conditions.
Inland, a mix of VFR and MVFR ceilings with terrain obscuration and
widespread moderate to heavy precipitation through the day. Also,
gusty southerly winds will include wind gusts of around 35 kt at
KLMT through today. An airport weather warning is in effect for this
hazard. Winds will decrease this evening and rainfall will decrease
in coverage and intensity.
Wind situation will be challenging at KMFR. As the front moves
through the area early this afternoon, we expect winds to suddenly
increase and could be in the 20-30kt range. This episode of gusty
wind is expected to be abrupt but short lived. /FB
&&
.MARINE...Updated 900 AM PST Thursday 9 February 2017...Winds have
decreased below storm force but are still in the Gale Force
strength especially the gust. This will generate very high and
dangerous seas of around 15 to 18 feet at a dominant period of 11
seconds, and mariners should consider remaining in port until the
storm passes. The cold front will move onshore this afternoon.
Behind it, winds will veer to southwest and subside to advisory
strength by this evening.
A low pressure moving northeast toward Washington will bring an
increase in winds tonight with occasional gale force gusts into
early Friday morning...mainly north of Cape Blanco. Seas will
remain high and very steep into Friday then likely will be steep
during the weekend with a moderate northwest swell of around 8
feet at 11 seconds. Northerly winds may reach advisory strength
this weekend, especially in the outer waters south of Cape Blanco.
Conditions will improve Monday through Tuesday. The next cold
front has the potential for gales on Wednesday with seas becoming
high again. /FB
&&
.PREV DISCUSSION... /Issued 930 AM PST Thu Feb 9 2017/
DISCUSSION...
Heavy rain continues over the coastal areas and west of the
Cascades. IR satellite showing cold cloud tops up to -60C and a
very moist vertical profile ahead of this cold front. Another
impressive feature is the comma on IR satellite suggesting a
strong cyclone hitting it's mature stage, so strong winds are
likely to continue over the next few hours before tapering off
west of the Cascades. Therefore, feel headlines for wind are on
track.
The short term concern remains flooding in small streams and
urban areas with the possibility of flash flooding on burn scars.
We're already small stream flooding in Siskiyou county and along
the coast. Flash flooding on the other hand still has to be
monitored. In addition, we received a landslide report in
Dunsmuir, suggesting heavy rain is ongoing near the Shasta area.
We'll still have to keep an eye on Jackson and Josephine county
for the next few hours. The cold front should pass through the
west side by around 21 to 0z, so expecting the heavy precipitation
to start tapering off around that time. CZS
AVIATION...09/12Z TAF CYCLE...MVFR will remain widespread along the
coast with areas of IFR/LIFR...mainly along the south coast near
Gold Beach and Brookings. Periods of moderate to heavy rainfall and
strong, gusty south winds will continue in those areas today.
Winds will decrease only slightly this evening into Friday morning
as another system moves by to the north and continues showers with a
mix of MVFR and VFR conditions.
Inland, a mix of VFR and MVFR ceilings with terrain obscuration and
widespread moderate to heavy precipitation through the day. Also,
gusty southerly winds will include wind gusts of around 35 kt at
KLMT through today. An airport weather warning is in effect for this
hazard. Winds will decrease this evening and rainfall will decrease
in coverage and intensity. However expect local MVFR cigs to
continue with numerous mountain obscurations into Friday morning.
DW
MARINE...Updated 500 AM PST Thursday 9 February 2017...Storm
force south winds will continue until around 10 AM this morning.
This will generate very high and dangerous seas of around 18 to 24
feet at a dominant period of 11 seconds, and mariners should
consider remaining in port until the storm passes. The cold front
will move onshore late this morning. Behind it, winds will veer to
southwest and subside to advisory strength in the afternoon. But,
low pressure moving northeast toward Washington will bring an
increase in winds tonight with occasional gale force gusts into
early Friday morning...mainly north of Cape Blanco. Seas will remain
high and very steep into Friday then likely will be steep during the
weekend with a moderate northwest swell of 7 to 9 feet at 11 to 12
seconds. Northerly winds may reach advisory strength this weekend,
especially in the outer waters south of Cape Blanco. Conditions will
improve Monday through Tuesday then the next cold front has the
potential for gales on Wednesday with seas becoming high again.
DW
PREV DISCUSSION... /Issued 341 AM PST Thu Feb 9 2017/
DISCUSSION...A high-impact wind and rain event is underway. I'll
first detail the wind situation. South to north pressure
gradients are increasing across the forecast area. South wind of
50kt has been observed in the lowest levels scanned the North
Bend profiling radar, which is uncommon and indicative of how
strong the wind field is. Additionally, 10 observation sites
across 8 counties have recorded gusts of 57 mph or greater
overnight. Power outages have been noted in Bandon due to
wind/tree damage. The coastal strong winds will ease some late
this morning and afternoon, while some areas east of the Cascades
will experience high winds through the afternoon. Even West Side
valley locations will see some gusty conditions through the
morning...continuing into early afternoon as the cold front
passes through and unstable conditions bring some moderate
southwest winds through. Some West Side areas that received heavy
snow earlier this winter may have a significant number of weakened
trees, and any moderate to strong wind could damage these
further.
Next, heavy rain and flooding. An observed precipitable water
value of 1 inch at Medford during a 06Z balloon sounding is the
daily record for Feb 9. This is indicative of how much moisture
the latest atmospheric river event is bringing with it. Half inch
per hour rainfall rates were observed yesterday evening, and
radar/satellite imagery suggests another round of very heavy rain
is in store this morning for the coast and areas just inland. We
have issued an Areal Flood Advisory for Josephine and Curry
Counties as well as portions of Coos and Douglas Counties. Urban
and small stream flooding is possible with these heavier bands of
rain moving through. Main stem rivers like the South Fork of the
Coquille at Myrtle Point and the Coquille at Coquille are expected
to flood, and Flood Warnings have been issued for these points.
The Illinois River at Kerby is forecast to reach the highest level
since 1970, though current readings and a lull in the heavy rain
early this morning suggest it may peak below the forecast of 31.94
feet. Even so, the heaviest rain has yet to reach this area, and
the Illinois River will certainly rise rapidly this morning, and
folks along the river should monitor the river closely and take
necessary precautions.
The heavy rain will impact Siskiyou County later this morning,
and we have issued an Areal Flood Advisory for this area too. No
doubt that rapid snowmelt will result in sharp river and stream
rises, and some main stem rivers will flood, like the Scott River
at Fort Jones and the Klamath River at Seiad Valley. Additional
concerns exist for heavy rains atop wildfire burn scar areas like
the Gap fire and the Happy Camp and July Complexes. Flash flooding
is possible near these locations, and a Flash Flood Watch
continues through the morning.
Farther east, warm conditions and some rainfall is leading to
snowmelt and river rises, and we have issued Flood Warnings for the
Sprague River at Beatty and the Pit River at Canby. Latest model
data shows these areas receiving moderate rain amounts this
afternoon.
After another upper trough swings through Friday and brings moderate
snowfall to areas above 3500 feet, drying and warming daytime
conditions are expected, though overnight lows will be substantially
lower than recent nights because of the drier air mass and clearing
skies.
Please see the previous extended discussion below.
Sunday through Wednesday Night...The long term period
continues with the break in precipitation. Easterly winds during this
period will at least somewhat help to dry things out. High
temperatures west of the Cascades will rise into the mid to upper
50s while the lows will rise from the low to mid 30s to the upper
30s to low 40s through the period. East of the Cascades,
temperatures will remain slightly above normal during this time
frame with temperatures in the low to mid 20s raising to the low 30s
by the end of the week. Highs, on the other hand, will be between
the mid 40s to low 50s.
The next wet system will approach the area beginning Wednesday. This
will likely be a return to the wet and active pattern that we've
seen this winter. Although confidence is pretty high that southern
Oregon and northern California will see precipitation, confidence is
particularly low regarding the intensity and duration. Therefore, it
is difficult to pin down particular impacts. That being said,
despite the extended period being dry, it will be warm and snow
levels will continue to rise through the end of the week. So
although the small creeks and streams will have a chance to go back
to normal, it won't take an extremely strong or a long-duration
storm to create adverse impacts. Therefore, it is going to be
important monitor the upcoming situation as it unfolds. -Schaaf
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...High Wind Warning until 7 PM PST this evening for ORZ030-031.
Flood Watch until 10 PM PST this evening for ORZ025>031.
Wind Advisory until 7 PM PST this evening for ORZ030-031.
High Surf Advisory until 7 PM PST this evening for ORZ021-022.
High Wind Warning until 1 PM PST this afternoon for ORZ021-022.
Flood Watch until 4 PM PST this afternoon for ORZ021>023.
Wind Advisory until 4 PM PST this afternoon for ORZ023>025.
Flood Watch until 10 PM PST this evening for ORZ024.
High Wind Warning until noon PST today for ORZ027-028.
Wind Advisory until 1 PM PST this afternoon for ORZ026-029.
CA...High Wind Warning until 7 PM PST this evening for CAZ085.
Flood Watch until 10 PM PST this evening for CAZ080>085.
Wind Advisory until 7 PM PST this evening for CAZ085.
Wind Advisory until 1 PM PST this afternoon for CAZ084.
Flash Flood Watch until 4 PM PST this afternoon for CAZ080.
High Wind Warning until 4 PM PST this afternoon for CAZ083.
Pacific Coastal Waters...High Surf Advisory until 7 PM PST this evening for PZZ350-356.
Gale Warning until 4 PM PST this afternoon for
PZZ350-356-370-376.
Hazardous Seas Warning until 4 PM PST Friday for
PZZ350-356-370-376.
CZS/FJB/FJB