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
304 FXUS66 KPDT 051739 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 1039 AM PDT Fri Jul 5 2024 .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. Branham/76 && .PREV DISCUSSION... /issued 310 AM PDT Fri Jul 5 2024/ SHORT TERM...Today through Sunday...Water vapor imagery tonight shows an upper level ridge strengthening offshore western CONUS. Meanwhile, nighttime microphysics periodically has shown "hotspots" from vegetation fires starting up across the landscape from the days festivities, though most of these fires seem to have been by local authorities. Through the weekend, the upper ridge offshore will continue to build as it meanders east. Already under the influence of the ridge, temperatures increased into the 90s, with another 5 to 10 degrees of warming expected this afternoon. In fact, today will be the first real chance for areas of central OR, eastern Gorge, and the Columbia Basin to reach the century mark, with chances of 100 degrees between 55-70% in these areas. Chances will expand and increase across the lower elevations through the weekend, with chances in the aforementioned areas increasing to 85-95%, and 60-80% elsewhere in the lower elevations. With modest nighttime cooling expected over the coming days, HeatRisk will be increasing from moderate to major by Sunday. With such high HeatRisk, heat highlights have been issued and are in effect through next week for a prolonged heat wave. Besides heat, winds will generally be light and diurnally driven through the next several days as the ridge builds and shifts overhead. That said, confidence is high(80-85%) that breezy winds will develop through the Kittitas valley this afternoon, and will combine with relative humidities in the teens, resulting in the issuance of a Red Flag Warning this afternoon. A shortwave trough sliding down the northern Rockies will also help to increase winds Saturday through central OR and the OR Cascade east slopes, where Fire Weather Watches have been issued for wind and low RH. That said, confidence is only moderate(55-70%) in criteria being met Saturday, though best synoptic setup is advertised east of US97. Lawhorn/82 LONG TERM...Monday through Friday... Bottom Line Up Front 1. HEAT. 2. Breezy conditions return Wednesday and Thursday. 3. Fire weather concerns. Models are in firm agreement with an upper level ridge continuing to dominate the region through the midweek. Dry and hot conditions will persist through much of the long term. High temperatures will steadily increase through the period with the `hottest` day being Tuesday followed closely by Wednesday. 70% of the raw ensembles shows the Pendleton area to be over 100 degrees with the NBM putting Pendleton at 107 Tuesday, 110 through the Basin, 105 in central Wa and 109 through the Gorge. These temperatures are expected to continue through the work week with confidence temperatures staying above 100 degrees being high. EFI shows temperatures remaining well above seasonal normal of nearly 10 to 20 degrees. Looking at the HeatRisk tool, Tuesday is the day with the highest concern with HeatRisk levels reaching level 4 or extreme. You can find the definitions of the categories on the HeatRisk page wpc.ncep.noaa.gov/heatrisk/. With temperatures remaining above 100 for multiple days and overnight lows remaining in the upper 50s to low 60s, there is no real cool off period. Please see weather.gov/safety/heat for tips to remain safe during this heat event. Temperatures may `cool` ever so slightly Thursday with the models in firm agreement with a shortwave rippling across the region. This shortwave will bring with it a tightening of the pressure gradients at the surface along the Cascades. This will increase the winds through the Cascade Gaps and east slopes of the OR Cascades. Raw ensembles show a 60% probability of seeing winds of 15 mph or greater through the Kittitas Valley, the Columbia River Gorge as well as the foothills of the Southern Blues. While the winds are not entirely `elevated` this still brings us to the final point. Winds of 15 mph and relative humidities expected to be in the single digits to below 15% (80-100% of the raw ensembles show this) across the majority of the region. Due to the winds in the aforementioned regions as well as the critically low daytime RH values, there are some fire weather concerns across those areas at this time. This will continue to be monitored through period. Bennese/90 AVIATION...12Z TAFs...VFR conditions will persist through the period with mostly terrain driven winds. CIGs will be non-existent with SKC. Bennese/90 && .PRELIMINARY POINT TEMPS/POPS... PDT 95 61 96 61 / 0 0 0 0 ALW 97 63 98 64 / 0 0 0 0 PSC 99 65 101 64 / 0 0 0 0 YKM 100 62 100 63 / 0 0 0 0 HRI 100 62 102 63 / 0 0 0 0 ELN 96 63 99 61 / 0 0 0 0 RDM 97 56 100 56 / 0 0 0 0 LGD 91 58 92 57 / 0 0 0 0 GCD 94 58 98 57 / 0 0 0 0 DLS 104 66 104 66 / 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. Heat Advisory until 10 PM PDT Thursday for ORZ505-511. Fire Weather Watch from Saturday afternoon through Saturday evening for ORZ610-611-640. 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 from 2 PM this afternoon to 9 PM PDT this evening for WAZ690. && $$ SHORT TERM...82 LONG TERM....90 AVIATION...76