Surface
Chart, Radar and Satellite
Today
We’re
dealing with what’s left of Isaias. There are no real changes to what I’ve been
saying for the last few days.
.
The rest
of the week.
The weather
for this current week is going to be tricky. But what happens over the 2nd
half of this week, is going to depend on what happens out west and how two
tropical systems interact with an upper-level feature in the Pacific Northwest.
Tropical
I typically
don’t talk about tropical activity in the Pacific. But in this setup we have to
discuss it.
Tropical
Storm Rachel made landfall late Saturday night in northern Baja California and
is now a remnant low over the Southwest. Rachel will continue to gradually
weaken and turn to the northeast later today as it heads into southern Utah.
Hurricane
Simon
Simon has
strengthened to strong 145 mph Category 4 hurricane. Looking at the satellite
image, we can see his eye is very close the coast between Playa Perula and Cabo
Corrientes. Will this keep him from reaching Category 5? Maybe, maybe not. But
that really won’t matter as far as impacts. Simon is dumping a lot of rain over
parts of southwestern Mexico. Rainfall totals of 10 to 20 inches will bring a
lot of flooding. Simon should continue
to track northward along Mexico's coast. He should begin to gradually weakening
and looks to become a tropical storm Tuesday. But if his core moves ashore
quicker than expected he could weaken much quicker, as he interacts with the
higher terrain. His remnants very well could move north into the U.S.
We have an
upper-level trough sitting over the Pacific Northwest with a strong cold front
pushing across the Divide. This is pulling tropical moisture northward. With
the cold air that is in place this is bringing a lot of snow into southwest and
west-central Montana, into Idaho and Wyoming. The snow is also making it into
Alberta, British Columbia, and Saskatchewan. Most of this snow is above 4,000
feet. For Montana, general snowfall
today looks to be between 6 and 10 inches of snow through Monday morning. When all is done, this weekend storm will
bring 1 to as much as 4 feet of snow in the highest elevations, especially west
of the Divide.
The
upper-level low is going to work its way east. By Thursday what’s left of Simon
is going to be pushing into the Central Plains, bringing tropical moisture with
it. All of this looks to interact as things push into the Upper Great Lakes. We’re going to have high pressure building
over the Plains. This is going to allow the Middle part of the Country to warm
to well above average. While this is going on colder air will be falling down
the ridge axis into the Great Lakes, Midwest and East Coast. The question is how cold does it get? The GFS model is bringing in a lot of cold,
with the trough extending down near the Gulf Coast. The EURO model is much less
rambunctious with the dynamics. The GFS
is a bit farther west with the ridge than the EURO. All of this has big
implications on what happens in the Northeast and Northern Middle Atlantic next
weekend.
The Northeast will see clearing develop west to east tomorrow. Tuesday and Wednesday will turn milder, but as low pressure develops it will turn breezy (gusts of 20 to 30 mph) for Tuesday and Wednesday as the cold front approaches the region. Tuesday will see a few showers and isolated thunderstorms, as some of the moisture from Rachel gets mixed in. Then things will begin to cool off as Canadian air moves into the region. As the air gets colder Tuesday night rain showers will change over to a rain/snow mix over northern parts of the region, this will be especially true in the higher elevations above 2000 feet. The highest elevations could see a bit of accumulation. After a cold start on Wednesday temperatures will moderate and become quite mild. This will clear to the east. As a trough builds in from the west. We will cool back off again for Friday into the weekend. Then we will see another storm approach, this one will have moisture from Simon and likely some of Rachel enhancing things. How it turns out will depend on which model is correct. It will end up being a mix of that the GFS and EURO are thinking, but right now I think the EURO has the better handle on things. So, the northeast into the northern Middle Atlantic will become cool, likely cool enough for snow to mix in across New York State and northern into Central New England. Accumulating snow will be possible in the higher elevations of the Adirondacks, Greens, and Whites.
