Area Forecast Discussion
Issued by NWS Pendleton, OR
Issued by NWS Pendleton, OR
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003 FXUS66 KPDT 052139 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 239 PM PDT Fri Jul 5 2024 .SHORT TERM...Tonight through Sunday...High pressure ridge will now be firmly entrenched over the region well into next week, promoting significantly hot conditions and enhanced fire weather concerns. At this point confidence is very high (90-100%) in temperature across the weekend reaching at or above triple digits for most of our lower elevation locations; The Dalles has already hit 100 as of this writing, and with peak heating still a little bit away, we`re likely to see portions of the Columbia Basin and Yakima Valley achieve these temperatures today. Temperatures should slowly rise through the weekend about 1-3 degrees each day, with widespread triple digits the certainty for Sunday. These hot afternoon highs coupled with increasing overnight lows rising across the 60`s for the lower elevations will lead to widespread moderate to major HeatRisk values with pockets of extreme. Excessive heat warnings and advisories will continue into next week. A pair of disturbances rounding the ridge overhead are also tightening the pressure gradient leading to some locally enhanced breezes for the Kittitas Valley today and into Central Oregon tomorrow. This alongside the bone dry airmass will promote some elevated fire weather concerns, detailed in further in the Fire Weather section below. Goatley/87 .FIRE WEATHER...Red flag warning remains in effect until 9 PM this evening for WA Fire Weather Zone 690 (Kittitas Valley); Red flag warnings in effect for OR Fire Weather Zones 610, 611, 640, and 642 valid Saturday 2 to 9 PM. Both of these are in effect for critically low relative humidity values into the teens and single digits, and breezy winds around 10 to 20 mph with gusts to 25 mph. Enhanced winds are expected thanks to a pair of passing shortwave troughs to the northeast rounding the dominant ridge over our region, tightening the pressure gradient and bringing elevated winds. Sunday winds should decline, but some elevated winds may be possible in Central Oregon once again. Expect this will be brief and should not coincide long enough with lowered RH values to necessitate any fire weather products, but we continue to monitor for the potential. Goatley/87 .LONG TERM...Monday through Friday...The ridge remains in place through much of the long term forecast period. This system will continue to produce hot temperatures across the lower elevations. Temperatures of 100 degrees or greater are likely (60-100%) through the forecast period. Tuesday is anticipated to be the hottest day, with a 80-100% chance of temperatures above 100 degrees for the lower elevations, and a 30-50% chance for temperatures of 110 degrees or greater, mainly across the Columbia Basin. The ridge will generally move east of the area by Wednesday, allowing southwest flow develop across the region. Models do have variances with the progression of this ridge, with the clusters showing some timing differences. Additionally, the clusters show some disagreement with the timing and strength of the approaching southwest flow in the latter portion of the week. Moisture is currently present within this flow, allowing temperatures to remain high, though a few degrees of cooling is noted between Wednesday and Friday. Even with this cooling, temperatures will be 10-15 degrees above normal. The last mentionable concern will be wind during the latter half of next week. As the southwest flow develops, there could be an increase in afternoon winds, with a 60-90% chance of gusts of 25 mph noted across the western half of the CWA on Wednesday, and a 30-50% chance for 25 mph gusts for the same area into Friday. Branham/76 .AVIATION...18Z TAFS...VFR. High pressure across the region will continue to produce VFR conditions at area terminals. In addition to dry conditions, terminals will see wind less than 12 kts through the forecast period. Hot temperatures are favored for the next several days which could result in High Density Altitude at impacted terminals. Branham/76 && .PRELIMINARY POINT TEMPS/POPS... PDT 60 95 62 99 / 0 0 0 0 ALW 63 98 64 102 / 0 0 0 0 PSC 64 100 65 103 / 0 0 0 0 YKM 62 100 62 101 / 0 0 0 0 HRI 62 101 64 103 / 0 0 0 0 ELN 64 98 63 101 / 0 0 0 0 RDM 56 100 56 100 / 0 0 0 0 LGD 58 91 58 95 / 0 0 0 0 GCD 57 96 58 98 / 0 0 0 0 DLS 66 103 68 106 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...Excessive Heat Warning until 10 PM PDT Thursday for ORZ041-044- 507-508-510. Heat Advisory from noon Monday to 10 PM PDT Thursday for ORZ050. Red Flag Warning from 2 PM to 9 PM PDT Saturday for ORZ610-611- 640-642. Heat Advisory until 10 PM PDT Thursday for ORZ505-511. WA...Excessive Heat Warning until 10 PM PDT Thursday for WAZ024- 026>029-521. Heat Advisory until 10 PM PDT Thursday for WAZ523. Red Flag Warning until 9 PM PDT this evening for WAZ690. && $$ SHORT TERM...87 LONG TERM....76 AVIATION...76