Blistering heat last week in the Midwest has now taken aim at the Intermountain West as a gargantuan high pressure system moves into the Great Basin. High temperatures across the Pacific Northwest have been over 10 degrees above normal in some spots.
Got so hot in Tacoma, Washington, that a semi filled with bread dough lost some of its load as the yeast overheated and the dough overflowed onto Interstate 5.
Meantime, the East has seen a shift from summer to fall-like conditions. Boston normally sees highs in the low 80s this time of year. The last four days have seen average temperatures as low as 13 degrees below normal.
For our purposes, it’s important to distinguish between what is persistent and what is transient. In the East, the cool weather is transient, as temperatures are expected to modify in the next week to ten days. For the west, the heat is a semi-permanent feature, linked to a stagnant high pressure system, so that’s where we put our faith in the forecast.
Indeed, the “Western Ridge” as it’s called, is one of two stalwart high pressure systems that dominate the Lower 48 in the summer. While it bakes the West and drives the monsoon in Arizona, the Bermuda High cranks up the heat and humidity in the East. The two typically combine to thrust the jet stream north and keep us storm-free.
But the Bermuda high has been temperamental this summer, while the Western Ridge has been consistent. It’s for that reason we have been bullish on warmth in the Pacific Northwest, Far West and of course the Northern Plains (due to drought).
However consistent the Western Ridge has been this summer, it can still be usurped by tropical activity…as can any pattern, really. A recent uptick in the Pacific has caught our attention, and it has major implications for forecast consistency for the remaining months of the warm season.
It’s for this reason that we may be looking at volatility in the West and East in the coming 3-4 week period, and another example of how you must proceed with caution when the tropics begin to heat up.