textproduct: Eureka

SYNOPSIS

Dry conditions will continue across the area today and into early work week with some particularly cold mornings with lows near freezing and freezing. Conditions will slightly warm and moisten next week with increasing chances of wetting rain by mid week.

DISCUSSION

Persistent high pressure over the Northeastern Pacific has begun to shift eastward, promoting very dry and stable conditions across the region. Latest satellite imagery depicts high- level moisture and expansive cloud coverage spreading across NW California. High pressure is expected to slowly weaken and flatten into Monday as a weak shortwave trough moves north of the area, bringing increased cloudiness. Ridges tops could expected some gustier winds early this week as the weather pattern shifts.

The 500 mb ridge appears to slowly build back early this coming work week , with conditions slightly warming up. The pattern shifts as the ridge finally breaks down giving way to an upper level trough digging southward. This trough will approach the area by mid week. At this moment, there is a 50-80 percent chances of wetting rain (0.1 inch or more) Tuesday afternoon through Wednesday afternoon, with the highest probabilities remaining along the coastal range in Del Norte, Humboldt and Mendocino counties. Lesser rain amounts are expected inland in Trinity and Lake Counties. There are no major impacts expected with this weak weather system, and if precipitation does occur, it would be more beneficial than impactful, especially after the recent dry spell.

Ensembles CW3E models, and WPC Cluster Analysis suggests (25-35%) another shortwave trough may bring another chance of light showers for the northern portion of the area by late in the work week into the weekend. The EPS and GEFS show the next weekend rain totals look to be below 0.1" for each 24 hours period Friday-Sunday. /ZVS/DES

AVIATION...18Z TAFs

Dry offshore flow firmly maintains VFR conditions. Mostly light and variable winds at the terminals through much of this period. Mid to high level clouds have filled in from a clipping weather system. Increasing southerly flow from this weather system to the north will begin to increase the threat for turbulence and low level wind shear after 15Z Monday. The moistening southerly winds over the coastal waters will introduce a slight chance for some stratus to push into CEC after 01Z Monday. CIG heights look to be in the MVFR levels at this time if this does occur. JJW

MARINE

Seas have fallen below 5 ft by today as winds remain light. Southerly winds are beginning to increase some across portions of the waters. A series of small, mid to long period west swells fill in through Tuesday, each peaking at around 5 ft. Winds turn southerly and start to increase early Monday. NBM currently shows about a 70% chance for gale force gusts in the outer waters by Tuesday, with slightly higher confidence north of Cape Mendocino. If the forecast continues to trend higher, the northern inner zone (450) may need to be considered for a Gale Watch or Hazardous Seas Watch. A mid period WSW swell will arrive Wednesday, followed by a large westerly swell Wednesday night and Thursday. JB/JJW

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from 10 AM Monday to 2 AM PST Tuesday for PZZ470-475.

Gale Watch from late Monday night through Tuesday evening for PZZ470-475.