textproduct: Seattle/Tacoma

SYNOPSIS

High pressure will allow for warm and dry conditions today. Increasing clouds tomorrow as a weak, dry front will progress through the region late Thursday into Friday for another round of cloud cover and reduced temperatures, but high pressure amplifies over the weekend and into early next week for more significant warming. Onshore flow looks to resume Monday into next week.

SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/

Warm conditions and mostly clear skies prevail over western Washington today. Temperatures as of 2 PM are in the upper 50s to low 60s. Highs today should top out into the mid to upper 60s this afternoon. Clouds will begin to increase overnight in the early morning hours on Thursday as a dry front begins to approach the area. This may also push the marine layer onto the coast for a brief period Thursday morning. Lows will be warmer, into the low to mid 40s. Despite the increased cloud cover, the ridge axis will be overhead and should allow temperatures to climb into the low to mid 70s across much of the interior, with 60s continuing along the Pacific coast and northern interior coastlines. The warming trend will be stunted briefly on Friday as cloud cover remains in place and the ridge gets pushed into the intermountain west with an upper level trough forming just offshore. Lows will be much warmer, in the upper 40s to near 50. Highs in the upper 60s to low 70s.

LONG TERM /SATURDAY THROUGH WEDNESDAY/

A clearing trend is in store for Saturday as the aforementioned trough deepens into a closed low and moves southward towards the Oregon and California coasts. As the low moves southward into Sunday, ridging then redevelops to the north over southern British Columbia, keeping skies clear and allowing temperatures to continue to warm into the weekend. The ridge moves overhead on Monday, and this day will have the greatest uncertainty in temperatures as they may be curbed by increasing onshore flow. Highs will climb to the 70s to low 80s by Sunday, and with that, relative humidity will also be markedly lower, reaching the 20-35% range. This warmth will also being to approach moderate HeatRisk for some locations, with a 40-80% chance of reaching Moderate HeatRisk levels in the Cascade and Olympic valleys, and much of the southwest interior. Temperatures will begin to lower back into the 60s and 70s Tuesday and beyond as the ridge begins to flatten and more robust onshore flow continues.

AVIATION

Northerly flow aloft continues as a ridge moves across western WA tonight into early Thursday. VFR conditions and mostly clear skies will prevail through tonight. High clouds will begin to move in Thursday morning as a dry front begins to approach the area. A marine layer is forecast to develop along the Pacific Coast, which may allow for IFR to LIFR conditions during the early morning hours at HQM, but should erode away by 18Z Thur. Elsewhere, VFR conditions continue with high clouds persisting through much of the day Thursday. North winds 8 to 15 kt will ease after sunset becoming variable to calm tonight. N/NW winds resume again during the day Thursday at around 5 to 10 kt.

KSEA...VFR conditions through the TAF period. High clouds increase after 15Z Thur and continue. N winds 8 to 12 kt will decrease tonight, becoming more NE overnight before turning back to NW during the day Thursday.

MARINE

Broad high pressure over the coastal waters will be interrupted briefly by a dry cold front that will traverse the area Thursday night into early Friday. High pressure well offshore continuing through the weekend and low pressure inland will maintain north winds the the area. Gradients (and thus winds) will increase Thursday night as the front moves through, as well as Saturday and Sunday, making for slightly increased winds through currently sustained winds look to remain below Small Craft Advisory thresholds. An onshore push looks in store for Monday and into Tuesday as a disturbance moves by to the south across Oregon and northern California. Seas remain 8 ft or less through the next 7 days.

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HYDROLOGY

No river flooding is expected in the next seven days.

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...None.