textproduct: Seattle/Tacoma

SYNOPSIS

Front moving east of the Cascades this morning. Trailing upper level trough moving over the area later today. The trough will move east Wednesday. Upper level ridge beginning to build Wednesday night. Weak system moving by to the north will slow the ridge building Thursday. Strong upper level ridge building offshore Friday with the ridge moving east through the weekend. Low level flow going offshore Saturday night with record highs possible Sunday and Monday.

SHORT TERM /TODAY THROUGH THURSDAY/

The latest forecast generally remains on track, with updates to the aviation section below. Front moving east early this morning with trailing upper level trough moving over the area later in the day. Strong westerly push down the Strait of Juan de Fuca behind the front with a convergence zone forming over Snohomish and Southern Skagit county. Breezy southwesterly winds behind the front coming up the Puget Sound will keep the convergence zone north of the King county line. Shower coverage increasing and a slight chance of thunderstorms this afternoon with the trough overhead. It will be another cool day with highs in the mid 50s to lower 60s.

Upper level trough hanging over the area tonight keeping at least a chance showers in the forecast. Southerly surface gradients weaken overnight allowing the convergence zone to drift south into King county after midnight. Lows in the mid 40s to lower 50s.

Trough moving east Wednesday bringing an end to the shower threat. Convergence zone dissipating in the Central Cascades early. Onshore gradients weakening during the day. This combined with the near solstice sun will dissipate the marine layer in the afternoon giving the area some sunshine. High temperatures will be warmer but still a little below normal, in the 60s.

Upper level ridge starts to build Wednesday night but a weak system riding by well to the north Thursday puts a temporary halt to the ridge building. Even so temperatures aloft warming and low level flow remains flat. With plenty of sunshine highs Thursday getting into the mid 60s to mid 70s. Lows Thursday morning will be a little cool, in the 40s. Felton

LONG TERM /THURSDAY NIGHT THROUGH MONDAY/

Upper level ridge building offshore Thursday night with the ridge axis near 140W through Friday. Ridge shifting east over the weekend with 500 mb heights going from the mid 570 dms to the upper 580s and lower 590 dms by Sunday afternoon. Thermally induced surface trough moving up the coastline reaching Washington Saturday night with the low level flow going offshore Sunday and Monday. Temperatures aloft warming with the ridge building. 850 mb temperatures peaking around plus 20C Monday. All this adds up to a warming trend through the period with possible record highs Sunday and Monday. Highs in the 70s Friday warming to the upper 70s to mid 80s Saturday, 80s Sunday and 80s to mid 90s Monday. Lows in the mid 40s to lower 50s Thursday night warming to the 50s and lower 60s by Sunday night.

Minor HeatRisk Friday and Saturday increasing to moderate Sunday and Monday. Right now Monday looks to be the peak of the heat.

Here is a list of some record highs for Sunday and Monday. Seattle Sunday 86 degrees set in 1988 and Monday 88 set in 1963. Olympia 88 degrees both days, 1999 for Sunday and 1963 for Monday. Bellingham 83 in 1988 Sunday and 82 in 1961 Monday. Hoquiam 79 in 1988 Sunday and 81 in 1961 Monday. Quillayute 84 in 1988 Sunday and 80 in 1969 Monday.

Felton

AVIATION

A cold front has moved through the terminals this morning under a trough, with flow increasing out of the northwest today behind the trough. Lingering showers will continue through today, with an organized convergence zone continuing in Snohomish County through most of the day today. Local IFR conditions will likely continue at times in the convergence zone with reduced visibilities/ceilings from the steady rain. Outside of the zone, ceilings have improved to MVFR and VFR for most terminals, with ceilings trending to VFR through the afternoon for thew interior. MVFR likely lingers along the coast, and lower ceilings in the mountains. There is a 40-60% chance of MVFR ceilings redeveloping Wednesday morning, with ceilings as low as 1,000 ft. Breezy southwest winds have picked up in Puget Sound this morning, with gusts up to 25 kt through Wednesday morning. Gusty west winds in the Strait of Juan de Fuca will linger into Wednesday, with highest winds today up to 30-35 kt. Coast will see winds turn to the northwest through today, with gusts up to 20 kt.

KSEA...Ceilings have improved to MVFR, ensembles keep the likelihood of MVFR through roughly 20-23Z, with improvement to VFR later in the afternoon/evening. Breezy winds out of the southwest will pick up through the day, with sustained winds 10-15 kt gusting to 25 kt through the day. Few vicinity showers will linger around the terminal (a more organized convergence zone will persist to the north of the terminal). There is a 40-60% chance of MVFR redeveloping overnight/Wednesday morning (due to lingering moisture).

HPR

MARINE

Northwesterly winds over the coastal waters expected to maintain SCA winds and seas throughout the remainder of the morning before easing by noon today and becoming more westerly. Southwest winds also increase for interior waters this morning and continuing through the afternoon. Small Craft Advisory winds and gusts are expected for most waters with this strengthening onshore flow. A strong west push through the Strait of Juan de Fuca is expected to result in gale force wind gusts for the central and eastern Strait and inherited Gale Warning looks good. Winds slowly ease tonight into Wednesday.

Winds become lighter Wednesday as high pressure builds back into the Coastal Waters. Northwest winds over the Coastal Waters increase Thursday into late week as high pressure continues to build offshore. Flow will transition to offshore at times over the weekend into early next week as a thermal trough expands northwards along the coast.

Seas will range between 6 to 9 feet today with isolated areas in the central and southern outer coastal waters seeing 10 or 11 foot seas. Not expected to be widespread before seas begin to ease this afternoon, inherited 11 AM expiration for the current SCA looks to cover this aspect of the forecast well. Seas subside to 4 to 7 feet by Wednesday and remain in this range into late week.

18/JD

FIRE WEATHER

No fire weather concerns until the warm temperatures beginning this weekend. Low level offshore flow will drive minimum relative humidity values down below 30 percent Sunday and Monday. Some the drier locations like Cascade valleys and the Southwest Interior minimum RH values will drop into the teens. Fine fuels will be approaching critical thresholds this weekend and larger fuels will be drying out as well. Elevated fire weather conditions beginning Saturday and continuing through the early part of next week across the area.

Felton

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...Small Craft Advisory until 2 PM PDT this afternoon for West Entrance U.S. Waters Strait Of Juan De Fuca.

Gale Warning until 11 PM PDT this evening for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory until 11 PM PDT this evening for Admiralty Inlet-Northern Inland Waters Including The San Juan Islands.

Small Craft Advisory until 8 PM PDT this evening for Puget Sound and Hood Canal.

Small Craft Advisory until 11 AM PDT this morning for Coastal Waters From Cape Flattery To James Island 10 To 60 Nm- Coastal Waters From Cape Flattery To James Island Out 10 Nm-Coastal Waters From James Island To Point Grenville 10 To 60 Nm-Coastal Waters From James Island To Point Grenville Out 10 Nm-Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm-Coastal Waters From Point Grenville To Cape Shoalwater Out 10 Nm.