An Upper Level High Pressure Ridge (“Arch”shape) still keeps us hot.  The graphics for days 1-3 show a weak cold frontal system moving through the Pacific Northwest Friday to start dropping temperatures.. The graphics for days  Saturday through Wednesday show a cold frontal system pushing through the Pacific Northwest by  Saturday and Sunday.

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ADVISORIES:

• A RED FLAG WARNING IS IN EFFECT FROM 1 PM THURSDAY UNTIL 10 PM FRIDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR THE LOWER COLUMBIA BASIN OF OREGON AND THE EASTERN COLUMBIA RIVER GORGE OF OREGON.
• A RED FLAG WARNING IS IN EFFECT FROM 1 PM THURSDAY UNTIL 10 PM FRIDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR THE WARM SPRINGS RESERVATION.
• A RED FLAG WARNING IS IN EFFECT FROM 1 PM THURSDAY UNTIL 10 PM FRIDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR THE CENTRAL MOUNTAINS OF OREGON.
• A RED FLAG WARNING IS IN EFFECT FROM 1 PM THURSDAY UNTIL 10 PM FRIDAY FOR WIND AND RELATIVE HUMIDITY FOR THE JOHN DAY VALLEY.
• A HEAT ADVISORY IS IN EFFECT UNTIL 8 PM TONIGHT FOR CENTRAL DOUGLAS COUNTY AND THE EASTERN DOUGLAS COUNTY FOOTHILLS.
• A HEAT ADVISORY IS IN EFFECT UNTIL 10 PM TONIGHT FOR THE LOWER COLUMBIA RIVER, THE TUALATIN VALLEY, PORTLAND WEST HILLS AND CHEHALEM MOUNTAIN, INNER PORTLAND METRO, THE EAST PORTLAND METRO, OUTER SOUTHEAST PORTLAND METRO, WEST CENTRAL WILLAMETTE VALLEY, THE EAST CENTRAL WILLAMETTE VALLEY, THE WESTERN COLUMBIA RIVER GORGE OF OREGON ABOVE 500 FT., AND THE UPPER HOOD RIVER VALLEY.
• A HEAT ADVISORY IS IN EFFECT UNTIL 10 PM TONIGHT FOR THE BENTON COUNTY LOWLANDS, THE LINN COUNTY LOWLANDS, AND THE LANE COUNTY LOWLANDS.
• A FIRE WEATHER WATCH IS IN EFFECT FOR WIND AND LOW RELATIVE HUMIDITY FROM THURSDAY AFTERNOON THROUGH THURSDAY EVENING FOR THE JOHN DAY VALLEY, THE SOUTHERN BLUE MOUNTAINS, AND THE WARM SPRINGS RESERVATION.
• AN AIR QUALITY ADVISORY IS IN EFFECT UNTIL 10 PM THURSDAY FOR JEFFERSON COUNTY.
• AN AIR QUALITY ADVISORY IS IN EFFECT UNTIL 10 PM THURSDAY FOR KLAMATH AND LAKE COUNTIES..

HEALTH ADVISORIES:

• A PERMANENT HEALTH ADVISORY REMAINS IN EFFECT FOR THE SOUTH UMPQUA RIVER BAR. POOLS IN THE BEDROCK ALONG THE RIVERS EDGE ARE KNOWN TO DEVELOP BLUE-GREEN ALGAE (CYANOBACTERIAL) BLOOMS THAT CAN BE HARMFUL TO PETS AND PEOPLE IF ACCIDENTAL INGESTION OCCURS. SIGNS HAVE BEEN POSTED ALONG SEVERAL ACCESS AREAS ALONG THE  RIVER.

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• Clear with patchy evening smoke, clear and hazy late tonight,
• AM haze, sunny and a bit cooler Thursday, clear with patchy fog late Thursday night,
• Mostly sunny Friday, clear at night,
• Sunny and a bit cooler Saturday, then mostly clear with patchy fog late Saturday night.
• lows 60-58 warming back to 60 Saturday night highs 92-88.
• Patchy AM and late night fog, partly cloudy and a bit cooler Sunday, partly cloudy Sunday night.
• AM clouds with patchy, partly cloudy and a bit cooler Monday afternoon,partly cloudy with patchy fog late at night,
• Some AM clouds, sunny and a bit warmer Tuesday afternoon, mostly clear with patchy fog late Tuesday night,
• Then sunny and a bit warmer Wednesday.
•  highs 85-83 warming to 89 Wednesday lows 60-58 (seasonal averages high 87 low 58).

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Forecast for The South Oregon Coast Including Coos Bay and North Bend:

• Mostly clear with patchy evening coastal fog continuing overnight while mostly clear with inland evening haze with patchy inland fog late tonight, mostly cloudy late tonight.
• Mostly cloudy with patchy AM fog, sunny and cooler Thursday afternoon, mostly clear with patchy evening fog, mostly cloudy with areas of fog late Thursday night,
• Mostly cloudy with areas of AM fog, sunny and a bit warmer Friday afternoon, mostly clear in the evening, partly cloudy with patchy fog at night,
• Some AM clouds with patchy fog, sunny Saturday afternoon, mostly clear in the evening, partly cloudy with patchy fog late Saturday night.
• lows 52-54 highs 69-70.
• Patchy AM and late night fog, partly cloudy Sunday, partly cloudy Sunday night,
• Patchy AM/late night fog, mostly cloudy Monday and Monday night,
• Patchy AM fog, partly cloudy with patchy fog Tuesday afternoon, partly cloudy with patchy evening fog, areas of fog late Tuesday night,
• Patchy AM fog, partly cloudy and a bit warmer Wednesday afternoon.
• highs 70-69 warming back t0 70 Wednesday lows 54-52.
• (seasonal averages high 66 low 54).                                                                                                                                                                                                                                                                                                                                                                                                                         _______________

Forecast for the Northern Oregon Cascades including the Cascades in Lane County:

• Clear and hazy with areas of evening smoke, clear and hazy late tonight,
• AM haze, sunny and a bit cooler Thursday, clear Thursday night,
• Sunny and a bit cooler Friday, mostly clear at night,
• Sunny and a bit cooler Saturday, mostly clear in the evening, then partly cloudy late Saturday night.
• free air freezing level 16,000 ft. tonight and Thursday, 16,000 ft falling to 15,000 ft. Thursday night, then 15,000 ft. Friday through Saturday night.
• lows 52-48 highs 82-74.
• Mostly sunny and a bit cooler Sunday, partly cloudy Sunday night,
• Mostly sunny and a bit cooler Monday, partly cloudy at night,
• Sunny and a bit warmer Tuesday and Wednesday Wednesday, mostly clear Tuesday night,
• free air freezing level 14,000 ft. Sunday, 15,000 ft. Sunday night, 14,000 ft. Monday through Tuesday, then 15,000 ft. Tuesday night and Wednesday.
• highs 72-70 warming 76 Wednesday lows 48-45 warming back to 48 Tuesday night.