Area Forecast Discussion
Issued by NWS Pendleton, OR
Issued by NWS Pendleton, OR
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203 FXUS66 KPDT 020539 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 1039 PM PDT Mon Jul 1 2024 .UPDATED AVIATION...06Z TAFs...VFR conditions will prevail through the period. Main issue will be the gusty winds across many of the TAF sites. ALL TAF sites minus RDM/BDN are seeing sustained winds of 12 to 15 kts with gusts to 18 to 25 knots with gusts increasing at DLS near 16Z to 30 kts. PDT/PSC/YKM will all see a brief decrease in winds between 8 to 10Z to sustained winds 8 to 10 kts before another increase to 12 to 16 kts with gusts to 22 kts. CIGs will be SCT060-FEW060 at PDT/BDN respectively with the remaining sites at SKC. Bennese/90 && .PREV DISCUSSION... /issued 841 PM PDT Mon Jul 1 2024/ EVENING UPDATE...Slight change to the forecast. Ground observations are showing winds to continue to be gusty through the Yakima and Kittitas Valleys with sustained winds around 17 mph this last hour and gusting 20 to 25 mph. Guidance shows winds will likely continue to be breezy between 15 to 20 with gusts to 30 mph (80% probabilities) to continue through those areas through 11 PM before settling down and averaging between 5 to 10 mph. Otherwise, no changes to the forecast. PREV DISCUSSION... /issued 430 PM PDT Mon Jul 1 2024/ SHORT TERM...Tonight through Thursday...A persistent northwest flow aloft through the short term as a ridge oh high pressure builds over the eastern Pacific and slowly moves towards the coast. A weak shortwave in the northwest flow has been clipping the region today producing some convective showers from far eastern Wallowa county eastward. The showers over eastern Wallowa county will come to an end this evening. Otherwise, skies will be mostly clear overnight. Some locally breezy conditions (10-20 mph gusts 20s) along the east slopes of the Cascades will also linger into the evening before decreasing. A second shortwave in the northwest flow will clip the region on Tuesday but with the main convection staying further to the north over the northern Idaho Panhandle. The main impact will be some more locally breezy conditions developing along the east slopes of the Cascades that linger into the evening before decreasing. One last shortwave will again clip the region on Wednesday as it dives into western Montana. Again the main convection remains north and east of the forecast area with the main impact being the locally breezy conditions along the east slopes of the Cascades. High temperatures over the next couple of days will remain near normal with highs in the 80s in the lower elevations and 70s in the mountains. LONG TERM...Thursday through Monday...Models in pretty good agreement with the overall pattern, but differ in strength and position of upper level high. These discrepancies are reflected in the WPC cluster analysis. 85-90% of WPC cluster members show an upper level ridge over the Pacific Northwest through the period. They do vary in the position and amplitude of the ridge, especially Monday. These variations will have an impact on just how hot it gets and whether or not mid level moisture makes it over our southern CWA early next week. The ensemble models paint a similar picture with the ECMWF showing a more amplified pattern (hotter and drier) while the GFS is a little more moderated but still hot and dry. ECMWF`s highs for Sunday are about 5-10 degrees higher than GFS`s. By the end of the period, 40-45% of the members show an upper level trough over the Gulf of Alaska trying to nudge the upper high eastward and weaken it while 55-60% keep the ridge over the area. At this time, will lean towards the upper level high persisting through the period. In summary, confidence is very high (90-100%) an upper level ridge will impact the area with above normal temperatures but confidence decreases on just how hot. We`ll have to keep an eye on mid-level moisture rotating around the upper level high as it settles in over the four corners area late in the period. This scenario is prone to allowing moisture to creep into southern parts of our CWA for afternoon/evening convection. At this time, most of the moisture heads out to sea keeping the mid- levels too dry (precipitable water anomalies are near/slightly below normal), but we`ll continue monitoring it closely for possible fire weather concerns early next week. Earle/81 && .PRELIMINARY POINT TEMPS/POPS... PDT 54 82 51 82 / 0 0 0 0 ALW 57 86 54 85 / 0 0 0 0 PSC 60 88 57 89 / 0 0 0 0 YKM 57 86 53 87 / 0 0 0 0 HRI 58 87 55 88 / 0 0 0 0 ELN 58 80 53 83 / 0 0 0 0 RDM 47 82 45 84 / 0 0 0 0 LGD 51 80 48 78 / 0 0 0 0 GCD 48 83 47 82 / 0 0 0 0 DLS 62 82 57 87 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. && $$ SHORT TERM...91 LONG TERM....81 AVIATION...90