Blog Article
Hurricane Simon Cat 4 Nears Mexico; Rachel Floods Southwest
Cat 4 Hurricane Simon closes in on Mexico's coast as Rachel's remnants trigger a Moderate flood risk in the Southwest and Isaias wrings out one more Carolinas severe threat.
Hurricane Simon Grinds Toward Mexico's Coast While Rachel's Leftovers Soak the Southwest
Alright y'all, there's a lot on the board this Sunday morning, so let's get right to it. The headline is Hurricane Simon, a Category 4 beast sitting just offshore of west-central Mexico. But don't sleep on what's happening stateside either, because Rachel's moisture is setting up a genuine flood threat in the Desert Southwest, and Isaias just will not quit on the Carolinas and Virginia.
Hurricane Simon: An Extremely Dangerous Cat 4 Near the Mexican Coast
Simon is the real deal. As of the 3 AM advisory, NHC has it at 155 mph with a central pressure down to 930 millibars, parked about 60 miles southwest of Manzanillo and creeping north-northwest at just 6 mph. That slow forward speed is a problem on its own. The eyewall is grazing the coast right now, and Hurricane Warnings stretch from San Blas up through Manzanillo.
The Hurricane Hunters got into the core overnight and found a pressure of 928 mb with flight-level winds supporting that 135 knot intensity. This is a small, intense inner core, the kind of structure that can wobble in strength but stays dangerous the whole time.
Here's the timeline: Puerto Vallarta is looking at a 60 to 70 percent chance of tropical storm force winds, with landfall-area impacts finishing up by Sunday morning local time. Manzanillo's window closes even sooner. As Simon moves inland over the mountains of western Mexico, NHC and our own impact model expect rapid weakening, dropping from major hurricane to tropical storm to depression strength by around October 14. The bigger long-term worry there isn't wind, it's the rain. Western Mexico's terrain wrings out tropical moisture fast, and flooding and mudslides in those mountains will be a multi-day story even after Simon's winds fade.
This storm has no direct US impact, but if you've got family or business ties along Mexico's Pacific coast, this is an "already happening" situation, not a "watch and see" one.
Rachel's Leftovers: Moderate Flood Risk for the Great Basin and Southwest
Meanwhile, back on our side of the border, Post-Tropical Cyclone Rachel just pushed inland near Tijuana a little before sunrise, and it's still a 50 mph system moving north at 25 mph. Tropical Storm Warnings cover the San Diego to Imperial Beach stretch of the California coast, and WPC has a Moderate risk of excessive rainfall posted across the Great Basin and Southwest today. That's their highest category, and it means widespread flash flooding is a real possibility, not just an isolated chance.
The setup is textbook: Rachel's tropical moisture is running into a favorable jet dynamic over the Great Basin, with precipitable water values way above normal for this time of year. That combination tends to produce exactly the kind of training, heavy-rain-on-heavy-rain scenario that overwhelms desert drainages fast. The risk downgrades to Slight on Day 2 as a closed low settles into the Basin, then Marginal on Day 3 as it drifts toward the Four Corners.
If you're in Las Vegas, Phoenix, or anywhere in eastern Nevada and Utah today, keep half an eye on the sky. Desert flash flooding doesn't need hours of warning, it needs minutes.
Isaias Isn't Done With the Carolinas and Virginia
Remember Isaias? The storm that dumped nearly 13 inches of rain on parts of Alabama and spun up a tornado outbreak across Georgia and South Carolina yesterday? It's still out there, now a weak post-tropical system over eastern Tennessee, and it's accelerating northeast at 23 mph.
SPC has a Slight Risk of severe weather posted today for a swath running from Raleigh and Durham up through Richmond, with a Marginal Risk extending into Washington, DC. The setup: Isaias's remnant moisture interacting with a surface front is enough to support isolated severe wind gusts and, per SPC's own numbers, a 5 percent tornado probability (their Level 2 category) in that corridor. That's not an outbreak-level setup like yesterday, but after what Georgia and South Carolina just went through, it's worth your attention if you're in that zone.
WPC also has flash flooding on the table for the Appalachians and Mid-Atlantic today as the last of Isaias's tropical moisture wrings out over already-saturated ground.
Quieter Threads Worth Watching
- Montana's early winter: A Slight Risk of significant winter weather continues across central and southwest Montana, with 6 to 12 inches of heavy wet snow possible in the higher terrain around Great Falls and Bozeman through Monday morning. That's an early taste of winter for mid-October.
- Space weather: NOAA SWPC is calling for G1 Minor geomagnetic storming today, with G2 Moderate levels possible early on from lingering CME effects. Aurora watchers in the northern tier might get a show, but no widespread impacts expected.
- Severe weather, days ahead: SPC has already flagged a Slight Risk for Tuesday across the central and southern High Plains, including Dodge City and the Oklahoma Panhandle. We'll keep tracking that one.
How This Touches Your Weekend
If you're running the Chicago Marathon today, you're in good shape, that race sits well outside any of today's active risk zones. Folks headed to Austin City Limits Weekend Two or the Texas Renaissance Festival in Todd Mission should be fine too, with the Southern Plains storm threat still a couple days out. But if you've got plans in San Diego for the Niteharts Festival, keep an eye on those lingering Rachel bands moving through, since gusty wind and spotty showers are still possible as the system pulls away this morning.
Bottom Line
Simon is Mexico's problem today, and it's a serious one, but it has no direct US impact. Our two things to actually watch stateside are the Moderate flash flood risk across the Great Basin and Southwest from Rachel's remnant moisture, and a renewed, though lesser, severe weather and flood threat for the Carolinas and Virginia as Isaias finally clears out. Neither is a nationwide weather event, but both deserve a real plan if you live in those corridors today.