The only evidence of a weather disturbance across southern Oregon and northern California was some breezy winds this evening.
Radar imagery shows no returns with satellite showing clouds across the area. This disturbance will not bring a lot in terms of precipitation to the area with some light precipitation still expected overnight along the Coast, the Umpqua Basin, and the Cascades north of Highway 140.
After this slight disturbance, we’ll make a quick sprint toward summertime conditions. At least for a brief time.
NWS Medford remarks there is one word to sum up the extended period: hot! A strong upper ridge builds offshore on Tuesday, then gradually moves inland Wednesday into Thursday, bringing an early, peak- summer like pattern to the region this week and into next weekend.
This pattern will result in dry conditions and the warmest weather of the year so far, with Wednesday through Saturday expected to be the warmest days of the forecast period.
Expect upper 80s west of the Cascades and upper 70s east of the Cascades Wednesday through at least Saturday. The heat peaks Thursday and Friday west of the Cascades (Friday into Saturday east of the Cascades) as the thermal trough moves inland, and there’s a fairly good chance (70%) of 90F here in Medford on Friday.
If we do reach 90F this upcoming week, it will be the 8th earliest first 90F on record for Medford (records go back to 1911). Best chances are Thu-Sat (75-85% chance). NWS remarks they aren’t too concerned about widespread record breaking warmth (most records are out of reach), but the climate site at Mount Shasta City is shown to reach 82F both Thursday and Friday. This would challenge the records for those days which are 82F in 2013, 81F in 2020, respectively.
NWS Medford remarks high temperatures this week are going to give most people whiplash. In the same month we recorded the first 70F of the year at the Medford Airport (which was the 8th latest first 70F on record), we’ll see our first 80F of the year, and likely the first 90F in the same week, just two weeks later. The average high temperature over the last three weeks (04/01-04/21) was 58.3F (which happens to tie for 13th coldest average high temps for that date range). High temperatures later this week will be 20 degrees above normal (more like typical July weather), and 30 to 35 degrees warmer than we’ve been experiencing in the past few weeks.
It should be noted that overnight lows will also be around 20 degrees above normal, with lows in the 50s west side and in the 40s east side. We haven’t acclimated yet, so take it easy with any outdoor plans and get your AC ready. If you plan to recreate in or on the area waterways or lakes, please use caution and wear a life jacket if entering the cold water. It may feel hot outside, but remember the water is very cold and cold water shock is real thing.
When does the heat break? A negatively tilted trough slides up the western periphery of the ridge on Friday. It’s too far offshore to bring any changes in our weather, but it will start to break down the ridge and additional shortwaves will continue to weaken the ridge over the weekend. There are indications of a trough returning to the area early next week, but there are differences in strength and timing. Regardless of the details, there is general agreement that temperatures will trend cooler toward normal values Sunday into early next week.
One last thing to note and monitor is thunderstorm potential over the weekend. In true summer fashion, models are showing some moisture and instability moving into the area Saturday and Sunday as the ridge breaks down. It’s far too early to speak with any confidence on details, but NWS personnel will continue to monitor over the coming days.
Source: NWS Medford