It has certainly been warmer than normal over the Northwest during late summer, but what you might not know is that the eastern U.S. has been far cooler than normal.
Consider the plot of the temperature anomaly (difference from normal) for the past two weeks over the entire U.S. from the NOAA/NWS Climate Prediction Center. WAY colder than normal from the Rockies to the East Coast.
Here is a high-resolution view of the temperature anomaly at 5 PM PDT on Sunday.
Amazing. Some portions of the eastern U.S. were 10-20°F below normal! Very warm over SW Canada.
Why this anomaly pattern? A persistent, perturbed upper-level (500 hPa pressure, about 18,000 ft) pattern with a ridge (higher pressure) centered over SW Canada and a trough (lower pressure) over the eastern US. (see below, and anomaly from normal for the last week below).
The large-scale pattern will be changing over the weekend, with rain and cooling temperatures over the west and moderation of the cool temperatures over the east.
Tonight, we see the previous pattern with a ridge in the west and a trough in the east.
Hope you are right. So many new fires from the thunder storms. Keep us posted on rain and temp forcast, if just get a little rain, wont do much, but cooler temps and higher humidity will help them out. However, of get t-storms during this ridge break down and another ridge build, could not be good. Fingers crossed we dont have another ridge build.
ReplyDeleteEast of the Cascades has a lot of smoke. Tuesday night the moon (73% of disk) was a fiery orange.
ReplyDeleteThe warm/cold pattern is split near the 100th meridian. Historically this has been referenced as "where the Great Plains begin." {Said by someone from the East.} The division is that between the moist east and the dry west. The coastal rain forests don't count.
Now, we would call this transitional area between two different ecological communities an ecotone.
Miserably hot, humid and smoky in the lowlands of NW WA and SW BC and miserably hot and dry in the adjacent high country today. YVR recorded its all-time record max September dew point.
ReplyDeleteI just looked at the forecast for the next 10 days via the Weather Channel, which I tend to find relatively accurate most of the time.
ReplyDelete82 for the next couple of days, and I'll water plants at a friend's place while he is on vacation.
Then 70's over the weekend, with one day being only 69 the rest of the time, low to mid 70's with showers in the morning, sun in the afternoon and partly to mostly cloudy the rest of the time.
I think the summer heat is gone for the season finally.
Pretty impressive heat in B.C. the last couple of days. 40.8 C (105 F) in Ashcroft broke the national monthly record for the hottest temperature ever recorded anywhere in Canada during September.
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