Area Forecast Discussion
Issued by NWS Pendleton, OR
Issued by NWS Pendleton, OR
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
922 FXUS66 KPDT 070405 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 905 PM PDT Sat Jul 6 2024 .UPDATE... Forecast was updated to allow the red flag warning to expire. Winds have decreased so red flag warning conditions are no longer expected. Otherwise, a clear sky and hot conditions across the region. && .AVIATION... 06Z...VFR conditions are expected across all TAF sites. Winds have decreased over the area and are mostly 10 kts or less, though DLS still has some winds above 10 kts. These too should decrease to 10 kts or less over the next few hours. DLS, BDN and RDM should have a few hours of gusty winds late Sunday afternoon/early Sunday evening. DLS could gust 20 to 25 kts, while BDN and RDM gust to around 20 kts. However, gusts should decrease by around 02Z at BDN/RDM and around 03Z at DLS. && .PREV DISCUSSION... /issued 435 PM PDT Sat Jul 6 2024/ Updated for Aviation... PREV DISCUSSION... /issued 235 PM PDT Sat Jul 6 2024/ SHORT TERM...Tonight through Monday...High pressure ridge is in firm control now, with minimal changes to the forecast reasoning from the past several days. As this feature continues to slowly move eastwards during the period, expect temperatures to steadily rise 1-3 degrees each day, culminating with our hottest temperatures just beyond the short term on Tuesday. Ensembles continue to present the heat with high confidence in widespread triple digit temperatures with near certain confidence (90-100%), and high confidence (70-80%) locations such as the Columbia Basin and Columbia Gorge will see temperatures near or just around 110 by Tuesday but possibly as early as Monday. HeatRisk shows widespread moderate to major today, with widespread major and pockets of extreme for Sunday and Monday. The one caveat to the forecast has been morning lows, which the NBM has been notably warm biased for many lower elevation locations. This has been tempered with some edits based on the biases from the last couple of days to help alleviate that. Fire weather concerns today are already validating as we show several sites starting to reach red flag criteria as of this writing. Expect winds 10-20 mph with gusts of 25 for areas of Central Oregon and into the Southern Blue and Strawberry Mountains with significantly low RH`s into the single digits and teens. Sunday winds look to temper just enough that concerns should fall, but widespread teen and single digit RH values aren`t going anywhere anytime soon, and fuels will continue to bake under the summer heat. Goatley/87 LONG TERM...Tuesday through Saturday...The main concerns during the period will be continued hot and dry conditions area-wide. Heat highlights are currently out through Thursday evening for many of our forecast zones, and temperatures are anticipated to peak Tuesday and Wednesday. Ensemble NWP guidance favors a slow eastward migration of the anomalously strong mid- to upper-level ridge that is currently centered over NW California, culminating in a Four Corners High setting up by the weekend. Additionally, some semblance of offshore troughing in the Northeast Pacific and a northeastward-propagating shortwave will result in southwesterly flow across the forecast area Wednesday and Thursday. Elevated fire weather concerns are appearing more likely Wednesday afternoon and evening as a surge of westerly winds envelops the region, strongest through the Cascade gaps and across the Columbia Plateau. The increasing winds will be in response to eastward-directed pressure gradients as a trough passes offshore to the northwest. Moreover, the aforementioned eastward progression of the ridge will place the hottest surface temperatures inland, leading to a diurnal enhancement of surface pressure gradients that will help drive westerly winds. Additionally, cooling temperatures up through 850 mb will aid in 20-35 kt 850 mb winds through the gaps and across the Columbia Plateau. While no widespread Red Flag conditions are forecast on Thursday, localized breezy conditions and fire weather concerns are forecast to linger, mainly through the Cascade gaps. Some solutions are advertising a mid-level speed max amidst southwesterly flow transiting the Blue Mountains region Wednesday afternoon. While this would normally favor thunderstorms, moisture at all levels appears meager in forecast soundings, so confidence in any thunderstorm threat (dry or wet) is very low (<10% chance) at this time. Through the remainder of the period, ensemble mean 500 mb heights and individual ensemble clusters are in good agreement that warm to hot temperatures will continue, but details of the pattern remain unclear. By Saturday, some uncertainty develops with regard to monsoonal moisture being advected northward into the PacNW. Confidence is quite low (<10% chance) in this solution, and ensemble means favor near-normal PWATs. Plunkett/86 AVIATION... 00Z TAFS...VFR conditions (100%) probability with winds mainly less than 10 kts. The only exceptions will be at DLS, BDN and RDM where gusty winds to around 25 kts will linger through the evening today before decreasing to less than 10 kts. Gusty winds will redevelop again on Sunday afternoon in the 20 to 25 kt range. && .PRELIMINARY POINT TEMPS/POPS... PDT 60 100 62 102 / 0 0 0 0 ALW 60 103 62 105 / 0 0 0 0 PSC 63 104 65 106 / 0 0 0 0 YKM 68 102 70 105 / 0 0 0 0 HRI 62 104 64 106 / 0 0 0 0 ELN 59 102 63 105 / 0 0 0 0 RDM 54 101 56 101 / 0 0 0 0 LGD 53 95 56 99 / 0 0 0 0 GCD 54 98 57 101 / 0 0 0 0 DLS 65 108 67 108 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...Excessive Heat Warning until 10 PM PDT Thursday for ORZ041-044- 505-507-508-510-511. Heat Advisory from noon Monday to 10 PM PDT Thursday for ORZ049- 050-502-503. Heat Advisory from noon Monday to 10 PM PDT Tuesday for ORZ509. WA...Excessive Heat Warning until 10 PM PDT Thursday for WAZ024- 026>029-521-523. Heat Advisory from noon Monday to 10 PM PDT Thursday for WAZ030. Heat Advisory from noon Monday to 10 PM PDT Tuesday for WAZ522. && $$ SHORT TERM...77 LONG TERM....86 AVIATION...77