Sunday, September 6, 2015

Will the Remnants of Hurricane Ignacio Reach the Northwest?

Tuesday AM Update

Ignacio is here!  At least its transformed, non-tropical form is now moving into British Columbia. (see image)  We will only get some clouds and sprinkles.

Many of the Northwest's most intense and memorable storms had their origins as tropical storms.   For example, the October 12, 1962 Columbus Day Storm began as Typhoon Frieda in the western Pacific before if evolved into a hugely powerful midlatitude storm (see map).  There have been plenty of others.

So it is with some interest for meteorologists that a potent hurricane, Ignacio, approached Hawaii and then swung northward towards the Aleutians, being steered by a huge area of high pressure over the Pacific.

First, let me note that I have never seen so many tropical storms in the eastern Pacific as we've had the last few weeks.  Here are satellite images for August 30th---there are three category 4 hurricanes storms and one tropical disturbance...amazing.   This is a record according to the National Hurricane Center. As an aside, since I know this is going to stimulate the "new normal" crowd, I should note that the storms are probably the result of the very warm temperatures in place due to the strong El Nino that has developed.

Ignacio is east of Hawaii in these pics.

Let's follow a sequence of the satellite images. On Wednesday at 11 AM, the storm was north of Hawaii

And 11 PM on Friday, it was N-NW of Hawaii and evolving into a midlatitude storm, with a far less symmetric cloud shield.  But storms, like people, don't forget where they came from, and often such transitioning storms retain some of the strong inner circulation of their tropical roots.

The upper level (500 hPa, roughly 18,000 ft) map for 11 PM on Friday shows the big high in the eastern Pacific that is steering the remnants of Ignacio.  Ignacio is indicated by the closely packed circular lines north of Hawaii.

So will Ignacio circle around the high and slam into the Northwest?  Will the ridge of high pressure weaken it?

Let's find out what the weather forecast models are saying!  Here is the latest 12-h forecast from UW WRF for 5 AM Sunday showing 3-h precipitation and sea level pressure.  Ignacio is clearly seen, with fairly deep low pressure (lots of lines) and heavy precipitation near its core.  The big eastern Pacific high pressure is also quite evident.

By 8 PM Monday it is has rounded the NW part of the high and is heading for us!  Still plenty of juice.

Tuesday at 2 PM, it reaches the central BC coast, but has weakened considerably.

And by 5 AM Wed. Ignacio has been impaled on the BC coastal mountains and dying through the encounter.  Perhaps we will get a bit of cloudiness from it, here in Washington State.  Not much more.

So it appears that Northwest weather lovers looking for storm action may be disappointed, with  the remains of Ignacio moving into British Columbia.  But it is all so amazing:  a storm forming in the tropics off of southern Mexico takes a huge loop around Pacific, skirting Hawaii, practically reaching the Aleutians before it turns back to North America to hit western Canada.

Literally, what goes around, comes around.


Maxillomand said...

Is there any chance these storms will weaken the RRR or stir up the waters enough to dissipate the heat from The Blob? I ask this because the forecast has 87° weather returning to Portland next week after some much appreciated cooler weather.

Bill Reiswig said...

I think "New Normal" is kind of an odd phrase? It's more like "No Normal" or the "New Abnormal".

I liked Richard Brenne's comment on your blog ("Strongest Summer Storm in Northwest History") citing Kevin Trenberth: "Kevin says that all weather is now affected by climate change to one degree or another. Weather today is taking place in an entirely different context than the weather of decades ago."

The variability of weather can and has caused all sorts of extreme events... it's just that our planet is now warming (historically) rapidly. That variability takes place in this context. This rapid warming has and will continue influence weather. Weather patterns and systems are likely change over hundreds of years until a new equilibrium is found. I doubt there will be "normal" climate nor patterns for the foreseeable future.

faronium said...

At one point the national hurricane center had Ignacio transitioning to post-tropical well north of 45 deg. Lat. The lattitude of Oregon. While the N pac high and typically cold offshore waters would make it almost impossible, it's conceivable that the NW could get hit by a tropical depression or something more hurricane-like than a post-tropical cyclone. Result would probable be less windy than something like the Columbus Day storm, but much more rainier.

Mark said...

Are wind and rain better than heat and sand?

From climate dot gov

On July 30 in Bandar Mahshahr, at 4:30pm, the temperature was 111°F and the dew point 88°F, making the heat index value a whopping 155°F, an unfathomably high number. The next day, July 31, at 4:30pm, the heat index soared to 165°F, after a temperature of 115°F was reached while the dew point was 90°F.

The explanation for these astronomically high dew point values lies to the south of Bandar Mahshahr: the Persian Gulf. On the July 30 and 31, winds were out of the south, blowing onshore from the water. Sea surface temperatures in that region of the Persian Gulf were at least a bath tub-like 90°F. An already hot area of the world combined with winds blowing over a hot water source led to the potentially deadly heat indexes recorded in southwest Iran.

From ABC News:

An unseasonal sandstorm swept across the Mideast on Tuesday, blanketing Beirut and Damascus, causing the deaths of at least five people and sending hundreds of others to hospitals with breathing difficulties, officials said.

Reduced visibility prompted the Syrian government to call off airstrikes against rebel fighters, local media reported, and threatened planned protests by Lebanese activists over the government's inability to deal with the country's rampant trash crisis.

The storm also hit Jordan, Israel and Egypt. In Jordan, schools shut down or cut their days short.