Area Forecast Discussion
Issued by NWS Pendleton, OR
Issued by NWS Pendleton, OR
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222 FXUS66 KPDT 010505 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 1005 PM PDT Sun Jun 30 2024 .UPDATED AVIATION...06Z TAFs...VFR conditions will prevail through the period. Breezy conditions will remain the primary focus with winds gusting to near 20 to 25+ kts with the exception of PSC which will remain below 10 kts. CIGs are mostly high giving way to clear skies. Bennese/90 && PREV DISCUSSION... /issued 223 PM PDT Sun Jun 30 2024/ SHORT TERM...Tonight through Tuesday... Key Points: 1) Breezy each day with gustier conditions possible for our normal windy spots. 2) Low chance of scattered showers, possibly thunderstorms this afternoon and tomorrow for Wallowa County. 3) Stabilizing on Tuesday with a dry northwesterly flow setting up on the front side of a Pacific ridge. Areas of scattered showers have been noted in and nearby Wallowa County this afternoon, and are expected to continue to be possible through the beginning of the evening. There is a low chance (15% or less) of isolated thunderstorms as well, but the majority of this activity is expected further to the east in more favorable environments, and any activity that does occur is not expected to be particularly strong with lightning and some gusty outflow winds possible. Meanwhile a few breezes occurring mainly near the Kittitas Valley and Columbia Gorge, weakening into the nighttime hours. For tomorrow, the trough will continue eastwards, but a secondary shortwave is indicated by models to round this feature and help to produce another round of precipitation activity in the Wallowas as well as further breezy winds. Probabilities for any showers tomorrow are even less than today (30% or lower), and thunderstorm chances 10% or less as well. The pressure gradient is expected to remain enhanced and continue to promote breezy winds with tomorrow expected to bring the gustiest winds of the week. Still, probabilities as indicated by the NBM remain on the lower side for any wind advisory level gusts or higher (45+ mph), with the highest chances near the Kittitas Valley at around 40-80%. This combined with only modest flow at the 850 mb level leads to moderate to high confidence (60-80%) that isolated gusts 40-45 mph will be possible, but widespread and frequent 45+ are unlikely. Meanwhile more widespread 20-30 mph gusts are expected for most of the forecast area, but with fair amounts of moisture still lingering, fire weather concerns will be enhanced but not high, precluding any need for red flag products with moderate to high confidence (60-80%). Tuesday is when conditions calm and we should see a ridging pattern beginning to build. A thermal trough should promote another round of breezy winds primarily across the Cascade gaps with speeds in the 20-30 mph range. Relative humidities will begin to drop notably however, with portions of the Columbia Basin and Central Oregon back down into the 20`s and teens for minimum RH`s. Temperatures through the next couple of days will remain fairly moderated, with 80`s to right around 90 for our population centers. Goatley/87 LONG TERM...Wednesday through Sunday...Deterministic models and ensembles are in good agreement on the 500 mb pattern through much of the period, though some differences among the clusters exist particularly on Sunday that could impact the temperature forecast. The probability of measurable rain during the entire period is very low at less than 5%. The ensembles are beginning to settle on a more offshore ridge solution through at least Saturday with the PACNW in NWLY flow aloft but with gradually warming temperatures. On Wednesday high temperatures will be within 2-3 degrees of normal and it will be a bit breezy in the Cascade gaps in the afternoon and early evening. NBM 4.2 gives KELN a peak wind gust of 36 mph at 00Z Thursday. The probability of needing wind highlights on Wednesday is low (10-20%). On Thursday high temperatures will warm to the lower to mid 90s across the lower elevations. Friday through Sunday will be hot with the probability of temperatures exceeding 90 degrees at 90-100% for the Columbia Basin and adjacent valleys and foothills, with 70-80% chances for the remaining elevations below 3500 feet MSL. A few low 100s will be possible each day (50-60% chance) in the Columbia Basin. The most likely scenario depicted by the ensemble clusters for Saturday into Sunday (40% of the ensemble members) is for a shortwave trough to move across the region in the NW flow aloft and suppress the ridge somewhat. This could act to cool the temperatures slightly over the weekend making the hottest day of the week on Friday as depicted in the latest GFS/MEX Guidance. For now went with the NBM which has the hottest day on Saturday...but Friday through Sunday will be hot regardless. The experimental HeatRisk product shows widespread moderate category Friday through Sunday with a few small patches of major category indicating that the heat may become a problem for heat sensitive individuals by late in the week. 78 && .PRELIMINARY POINT TEMPS/POPS... PDT 56 82 54 83 / 0 0 0 0 ALW 59 86 57 86 / 0 0 0 0 PSC 60 89 58 90 / 0 0 0 0 YKM 54 85 51 87 / 0 0 0 0 HRI 59 88 56 88 / 0 0 0 0 ELN 57 79 54 80 / 0 0 0 0 RDM 47 80 45 83 / 0 0 0 0 LGD 51 77 49 80 / 0 10 0 0 GCD 49 80 47 83 / 0 0 0 0 DLS 60 83 56 82 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. && $$ SHORT TERM...87 LONG TERM....78 AVIATION...90