I noticed a change in the latest model projections last night before I went to bed. And lo and behold this morning I awoke to the sound of rain pelting on the roof.
We have already received around 10mm of rain. The model now says we will get up to 16mm (0.64in) of rain between this morning and Wednesday morning,
The majority of that should fall before noon as a cell of rain showers moves from southeast to northwest up the Island.
Once that passes through we might get a few bits of drizzle or showers off and on for the rest of the day but that will be mostly it.
We look dry and getting hotter through the rest of the week. There is again some disagreement between the UWash models and Environment Canada for how hot it will get on the weekend but it will no doubt be near 30°C no matter what.
After what was a strangely normal April… we went back to a regime of consistent above average temperatures in May. High temperatures were more than 4ºC above normal for our highs and 3ºC above normal for our lows. Despite the well above normal temperatures we only managed to set 4 new record high temperatures at the Airport, and none of them were all time records for the day according to the long-period stations in the Valley.
In previous years, a dry and warm May might have meant a big freshet as the streams filled with snow runoff. So really what set this May apart was, again, the lack of snow on the mountains to contribute to our rivers and streams. Anecdotally, our local lakes including Sproat, Great Central, Stamp and others are all at “August lows”. Looking at the mountains, Mt. Arrowsmith looks like it might on September 1st rather than June 1st. And Mt. Kiltsa, which often has snow on its upper reaches through the summer and fall… is nearly bare as well.
Fire Danger on High – Expect Extreme by mid-to-late June.
The concern going forward will be fire. We are currently at a High fire danger rating. An open burning ban is now in effect inside and outside of the City and if the dry weather continues I would expect us to get to an Extreme danger rating near the middle to end of June.
Rainfall measurements improve at Airport
After months with only a few days of reported precipitation, it appears that perhaps something has been fixed at the Airport. This months report “only” omits the first 5 days of rain (which of course were the ones with the most precipitation at other stations). I am hopeful that the consistency will hold through the summer and especially fall. We might not have much to measure this summer, but surely we will want to catch that first rainfall in the autumn so we can get a good idea of when our dry season is over. You never know, we might also get the odd thundershower induced downpour in August or September like we did last year. No matter what, we need that official station to function properly.
El Niño update
The latest El Niño forecast was released May 14th. The new one will not be released until the middle of this month. I’ll post the June update in the June Summary. The main synopsis of the latest one is:
There is an approximately 90% chance that El Niño will continue through Northern Hemisphere summer 2015, and a greater than 80% chance it will last through 2015….
…. Collectively, these features reflect weak to moderate strength El Niño conditions.
Outlooks — Spring and Summer looking warm and dry.
Here is a new feature for this summary. The current 15 day outlook from the super-long range ensemble model from Environment Canada available at Spotx.com. The outliers are pretty high, but the mean forecast is less than 20mm of rain over the next 15 days, and the majority of that in the very short term which other models disagree with and none again until the final few days of the forecast which are the most unsure. Basically, after Tuesday it forecasts a full week and up to two weeks of no-rain. This is unusual for June.
I have not updated the rest of the long term forecasts since I just compiled them a couple weeks ago and they have not yet updated. But the reminder is that it is expected to be hot and dry all summer.
Below is the Sea Surface Anomaly map. I have retained last months prediction for the MJJ time period on the bottom. Notice the later period shows significantly more warmth in the El Niño rectangular box along the Equator. The persistent and abnormal warm water along the entire West Coast of the Americas is quite something, but especially the Northern portions.
City Stations Temperature Difference from normal: +3.4° C, +2.87º C, +4.03º C
Official (Airport) Temperature Difference from normal: +1.3º C, +2.9º C, +4.4º C
City Stations Precipitation difference normal: -79.67 mm (9.3% of normal)
Official (Airport) Precipitation difference from normal:
—- missing key days
*Denotes incomplete data for the month
Comparison to recent Mays at Alberniweather (unless specified)