Florence OR to Point St. George between 150 and 250 NM Offshore Forecast
5 - 15
20 - 30
30 - 40
25 - 35
25 - 35
|Today...N To Nw Winds 5 To 15 Kt, Becoming W To Nw. Seas 6 To 8 Ft.|
|Tonight...W To Sw Winds Less Than 10 Kt, Becoming S 10 To 20 Kt. Seas 5 To 6 Ft.|
|Mon...Se Winds 20 To 30 Kt, Becoming E To Se 35 To 45 Kt. Seas 5 To 8 Ft, Building To 9 To 14 Ft. Rain.|
|Mon Night...E To Ne Winds 40 To 50 Kt, Becoming N To Ne 30 To 40 Kt. Seas 13 To 22 Ft. Rain.|
|Tue...N To Nw Winds 25 To 35 Kt, Becoming N To Ne. Seas 12 To 21 Ft.|
|Tue Night...N Winds 25 To 35 Kt, Diminishing To 20 To 30 Kt. Seas 11 To 18 Ft.|
|Wed...N Winds 15 To 25 Kt. Seas 8 To 13 Ft.|
|Wed Night...N To Nw Winds 15 To 20 Kt, Becoming Nw 10 To 15 Kt. Seas 7 To 10 Ft.|
|Thu...W To Nw Winds 5 To 10 Kt. Seas 6 To 7 Ft.|
|Thu Night...W Winds 5 To 10 Kt, Becoming Sw. Seas 5 To 7 Ft.|
| Area Forecast Discussion|
National Weather Service Medford OR
415am PDT Sunday Mar 26 2023
A broad trough is over the region with northwest flow aloft. Models support light isolated to scattered showers today in portions of southwest Oregon and northern California. Otherwise, expect unseasonably cool weather with colder than normal temperatures today into Monday morning. Showers will taper off late this evening and tonight, then a much stronger low pressure system will approach the area on Monday. Then as this low approaches the southern Oregon coast it will bring a strong front into the area late Monday afternoon through Tuesday afternoon. Models show a high chance for heavy snow accumulations in the Mount Shasta region (including the I-5 corridor from Weed to Dunsmuir) and higher terrain over western Siskiyou late Monday through Tuesday. Additionally, moderate to strong gusty south winds are likely over the mountains and into the Shasta and southern Rogue valleys. The combination of snow and wind will also create periods of near whiteout conditions in the Mount Shasta region (Weed to Mount Shasta City area), especially Monday night and Tuesday morning.
.SHORT TERM...Light isolated showers are occurring this morning, especially along the coast. Light showers are expected to develop over inland areas during the day. Expect cool temperatures through the day. Morning low temperatures will be in the 20s to lower 30s across valleys west of the Cascades with lows in the mid to lower 30s at the coast. A frost advisory remains in effect for the Curry coast where temperatures have dropped to around 33 to 35 degrees overnight/early this morning and skies are mostly to partially clear. East of the Cascades, low temperatures this morning will be in the teens to lower 20s. Afternoon temperatures today will be slightly warmer than yesterday but still well below normal with highs in the upper 40s to 50s in western valleys and in the mid 30s to near 40 in valleys east of the Cascades. Along the coast, expect high temperatures in the mid to upper 40s.
Models indicate that showers will taper off late this evening and tonight. However, a strong low pressure system will approach the region. High clouds are expected spread over the area tonight. Otherwise, expect dry weather with cold overnight temperatures similar to this morning. Frost may be limited at the coast though due to the increase in high clouds.
Models are showing good agreement on the track and timing of the low pressure system moving towards the area tonight and Monday. The GEFS, ECMWF (European Centre for Medium-Range Weather Forecasts) ensemble and NAM all keep the surface low along 130W and near 43N during the day Monday, then track the low closer to the coast near the southern Oregon and northern California border Monday night into Tuesday. The surface low pressure is forecast to deepen to around 977 to 985 as it moves inside of 130W Monday night (when it is around 200 to 225 miles off the coast of southern Oregon). Given the good agreement between models and ensembles as well as between model runs on the track, timing and strength of this low, there is high confidence that this system will bring significant impacts into the area, especially across southern and western Siskiyou County where southerly flow will favor enhanced precipitation rates along with gusty south winds.
As this low deepens and nears the area, models indicate that a strong low level jet (50-70kt at 925 mb) will move over the coastal waters and a strong mid level 700 mb jet (50-60kt) will move inland. The stronger mid level winds combined with an increasing north-south pressure gradient across the area, is expected to result in moderate to strong gusty south-southeast winds in the southern Rogue Valley and Shasta Valley. A high winds watch (NPWMFR) for winds of 30 to 45 mph and gusting up to 60 mph remains in effect for the southern Rogue and Shasta valleys. Strong gusty winds are also likely over the mountains and possibly into the Scott Valley as well. Moderate gusty winds are expected to affect the southern Oregon coast and valleys east of the Cascades with breezy to gusty winds for most other areas. Over the coastal waters, gales are likely. (Please see the marine discussion below for details).
Light precipitation is expected to begin along the coast late Monday morning into Monday afternoon, then spread inland during the afternoon. Precipitation will then increase Monday evening through Tuesday morning, with moderate to heavy precipitation across western/southern Siskiyou, Curry, and into southwest Josephine County. Elsewhere expect moderate to light precipitation. Of note, locations in the southern Rogue and Shasta Valley (north of Weed) may see only light precipitation late Monday through Monday night, due to the effects of strong downslope winds. This may be followed by a period of light to moderate precipitation as the front moves through Tuesday morning.
There is a high chance for heavy snow across western and southern Siskiyou County with light to moderate snow impacts elsewhere, especially from the Cascades east and into higher terrain in Curry County and into southwest Josephine Counties. Snow levels are forecast to start at around 2500-3000 feet but then lower to between 1500-2000 feet early Tuesday morning. The moderate to heavy precipitation combined with low snow levels as well as strong, moist southerly flow will bring a high chance for heavy snow into the Mount Shasta region as well as for areas in western Siskiyou County (mainly above 2000 feet elevation). The National Blend of Models continues to indicate 24 hour snow totals of around 12 to 24 inches in the Mount Shasta region (from Weed to Dunsmuir) and in the McCloud area Monday evening through Tuesday afternoon, with a potential for high snowfall rates of 1-2 inches per hour Monday night and Tuesday morning. Additionally, with heavy snow combined with strong gusty winds, especially from north of Mount Shasta city to Weed and over exposed higher terrain, expect near whiteout conditions at times Monday night and Tuesday morning. Heavy snow is also likely in western Siskiyou, especially above 2000 feet elevation (mainly for W. Siskiyou Co west and south of the Scott Valley), with amounts of 10 to 20 inches possible. Moderate snow accumulations are possible across portions of the Southern Oregon Cascades and northern Klamath County (mainly north of Chiloquin) as well as the mountains in eastern Klamath and western Lake Counties.
There is more variability in the model forecast for snow in eastern Curry and southwest Josephine Counties. The National Blend of Models indicates the heavy snowfall amounts in the Siskiyous, south and southeast of Cave Junction, including for the Grayback Road area. Moderate to heavy snow is also possible in the Kalmiopsis, mainly above 2500 feet. Of concern, as snow levels lower early Tuesday morning with the back edge of the frontal precipitation band, there is a chance a brief period of accumulating snow down to valley floors in the Illinois Valley, from Hayes Hill south, and in the Klamath River Valley near Happy Camp.
We will continue to monitor this details of this storm and update the forecast with further information.
.PREV LONG TERM /Issued 259pm PDT Sat Mar 25 2023/
Precipitation in the Mount Shasta area should gradually diminish Tuesday afternoon into Tuesday night as the upper low moves south towards the Bay Area. There could be some wrap around moisture in portions of Northern California Tuesday night, including Mount Shasta, but were not expecting anything significant.
After Tuesday, we're not expecting any significant weather. Some wrap around showers from the upper low that will be south of our area could bring isolated to scattered showers mainly along and east of the Cascades. A weak upper trough will drop down along the Oregon coast Thursday which could trigger some showers Thursday afternoon, but were not expecting anything significant.
Another front could move into the area Friday night with moderate precipitation, followed by post frontal showers Saturday as another cold air mass moves in from the northwest. The operational models and the majority of ensemble members (ECMWF and GFS) show similar solutions, although there's some variation on timing. -Petrucelli
Updated 200am PDT Sunday, March 26, 2023...Improving conditions with a break from steep seas continue through Sunday night. This is short lived as a deepening low pressure system will come from the north and travel south over the Pacific and create hazardous conditions Monday and Tuesday. Strong gale force southeast winds and very steep wind-driven seas are likely over all waters Monday afternoon through Tuesday evening. A possibility for storm force winds exists Monday evening over the outer waters and south of Cape Blanco. After this system passes, steep seas continue through Wednesday morning before improving conditions return. -Hermansen
NOAA Medford OR Office: Watches - Warnings - Advisories
OR...Frost Advisory until 8am PDT this morning for ORZ022.
High Wind Watch from Monday afternoon through Tuesday evening for ORZ026.
CA...Winter Storm Watch from Monday afternoon through Tuesday morning for CAZ080>083.
High Wind Watch from Monday afternoon through Tuesday evening for CAZ081.
PACIFIC COASTAL WATERS...Gale Watch from Monday afternoon through Tuesday evening for PZZ350-356-370-376.