Gordon’s Rains Expected to Persist

An analysis of Tropical Storm Gordon’s potential impacts related to a fixed weather pattern over the Central U.S.

The Neverending Deluge: Pacific Heat + Fixed Jet Stream Parks Anomalous January Cyclone Lingling Over Philippines For Two Weeks

The vulnerable island chain that is the Philippines already sits on the firing line of tropical storm devastation. During a typical year, about 20 tropical cyclones roar ashore, wrecking all sorts of havoc. In a typical year, this amazing parade of such cyclones begins in June.

But now it appears that weather in the Philippines, which was already rather extreme, has gotten much worse. For so far, this island nation has been treated to a tropical storm season that hasn’t ended for at least 20 months. The storm season didn’t end in 2013, when January 1rst saw the formation of that year’s first tropical cyclone. And the season didn’t end with the winter of 2014 when the devastating rainmaker that was Tropical Storm Lingling formed on January 10th.


(Lingling Track. Image source: Commons)

Lingling developed to the east of the Philippines over a pool of abnormally hot and deep warm water. Temperature anomalies for this region ranged up to 2.5 C above average. Perhaps more importantly and more ominously, the depth of this abnormally warm water extended far below the surface.

In a Deepening Pool of Hot Water

Such strange and anomalous conditions are expected under a regime of intensifying human-caused warming. In the hottest regions of the ocean, evaporation is expected to intensify as warmth increases. Eventually, the surface water becomes saltier as it becomes hotter, causing it to sink. This mechanism transfers heat deeper and deeper into the world’s tropical oceans. This process is the start of a dangerous ocean turnover. One related to hypoxia, ocean current changes, and stratification. And it appears that just such a perilous heat transfer is beginning in a region of the Pacific east of the Philippines.

We won’t go too far into detail about the initial signs of tropical ocean warming and turnover or its other hazards and implications here. However, suffice it to say that a deepening hot water pool in this region of the world appears to, at this time, be having a profound impact on storm formation and strength. Namely, it has spawned the almost constant progression of storms mentioned above. A hurricane season without end for two years. It is also the mechanism that, according to NOAA fueled the extraordinarily powerful Typhoon Haiyan, one of the strongest storms on record, which devastated the Philippines in November of 2013.

Now the same zone has spawned the epic rainmaker that is Lingling to again harry the Philippines just two months later.

The Storm that Wouldn’t End Forces More Than a Million to Flee

Lingling formed over this anomalously deep, hot water then marched in through the southern reaches of the Philippines where it has been dumping copious amounts of rain over the islands ever since. You can note the almost zero movement of the cyclone from January 11 to January 23 in the MODIS image sequence below:

Lingling January 11

Lingling Janary 16

Lingling January 23

(Lingling January 11, 16 and 23. Image source: Lance-Modis)

By January 22nd, over the course of 11 days of near-biblical flooding, the storm had inundated some parts of the Philippines with an astonishing 52 inches of rainfall, more than the amount New York receives in an entire year. By today, the never-ending deluge had resulted in 1.14 million evacuated, 63 missing, and over 54 lost lives. Numerous bridges and dams were also destroyed by the flooding, along with hundreds of homes. This, just two months after the strongest tropical cyclone ever to make landfall struck the northern part of this vulnerable island chain.

And with the anomalous January formation of a devastatingly persistent Lingling, there is simply no respite.

Jet Stream Lag, Stalled Fronts, and Hot, Deep Water

Lingling’s persistence over the Philippines for so long can be attributed to numerous factors. First, the storm was caught up in a stalled frontal boundary whose tail end had snagged over the Philippines for about 15 days running. The front itself was caught up in a Jet Stream trough shoved south by a disrupted and collapsing polar vortex (one that currently appears to be in the process of getting ripped in half). So Lingling became indirectly linked with polar amplification related events further north.

The stalled frontal boundary and related Jet Stream lag also resulted in Lingling remaining parked over hot Pacific waters of great depth. Normally, the cyclonic action of the storm would pump cooler, deeper waters to the surface and result in the storm’s weakening. Unfortunately, the deeper waters were also quite warm, so Lingling maintained enough strength to continue dumping epic amounts of rain over the Philippines for two weeks straight.

Lingling front entagled 20 Jan

(Lingling, lower left, entangled in frontal system stretching all the way across the western Pacific on January 20, 2014. Front entanglement in a fixed Jet Stream pattern and related stalled frontal boundary helped result in Lingling’s 2 week persistence. Image source: Lance-Modis.)

This combination of conditions: hot, deep water, exceedingly early tropical storm formation (such that there is essentially no end to the Pacific cyclone season) and a lagging, persistent Jet Stream pattern resulting in an entirely abnormal storm event are unlikely to have occurred without the added weather forcing of human caused warming.

Unfortunately, the Philippines, at least for this year as in 2013, are likely to expect storm formation and impact to continue on throughout the year. Water conditions are certainly warm enough. So we will likely see the current 20 month storm season continue for another 11. A shift in winds, blowing the warmer waters east with an El Nino might bring some brief respite. But with human caused climate change pushing temperatures ever higher, we are likely to see the waters continue to warm, eventually over-riding such variability. In the end, the Philippines is indeed likely to see a never ending storm season.


Four Feet of Rain Floods the Philippines

More than a Million Forced From Their Homes by Lingling

NASA Lance-Modis


NOAA: Deep, Warm Water Fuels Haiyan Intensification

Through the Looking Glass of the Great Dying

190 mph Monster Cyclone Now the Strongest Hurricane Since 1980

Arctic ‘Heat Wave’ to Rip Polar Vortex in Half

Hat Tip to Colorado Bob

Mangled Jet Stream to Collide with Tropical System over Southeastern US for Major Rain Event?

Polar and tropical air masses setting up for another collision?

Polar and tropical air masses setting up for another collision?

(Image source: NOAA)

In the southeast this year, rain follows rain follows rain. Now a tropical system may be preparing to add its own moisture to the already very wet mix.

The river of upper level airflow called the Jet Stream begins an almost due south movement at the Arctic Circle near the Northwest Territory and Canadian Arctic Archipelago. The atmospheric river dives down over Central Canada and into the Great Lakes region. Continuing ever southward, it finally encounters a wall of warmer air setting up near the south Tennessee border where it speeds up and turns eastward, joining another Jet Stream flow coming in over the Rockies.

Riding along these convergent Arctic and Pacific Jet Stream flows are a number of wet and stormy impulses. Because this deep north to south dip has been in place over the Eastern and Central US for much of the summer, storm after storm has continued to impact a large region from Missouri to New Jersey southward through the Carolinas and then again southwestward along through Georgia and the Gulf Coast states. This persistent stormy pattern, a result of a slow, wavy, stuck Jet Stream, which is, in turn, caused by sea ice and snowfall loss in the Arctic, has pushed rainfall totals 20 inches or more above the yearly normal in some locations. It has delivered extraordinarily moist storms that dump inches of rainfall in just a few hours. And it resulted in some regions of Missouri receiving four months worth of rainfall in just one week.

In the above water vapor image, provided by NOAA, you can see the storms riding along the south frontal boundary of this Jet Stream trough through the Dakotas, Montana, Nebraska and Colorado then down into Texas, turning eastward through the Gulf Coast States and then surging north along the US East Coast.

Yesterday, this pattern delivered a powerful storm complex to Pennsylvania and New Jersey — flooding roads, knocking out power and dumping as much as six inches of rain. Now, the Jet Stream has driven further south, pushing the frontal boundary over the Gulf Coast and US Southeast.

Mangled Jet Stream trough over eastern US.

Mangled Jet Stream trough over eastern US.

(Image source: California Regional Weather Server)

But as if the convergent flows of the Jet Stream delivering very powerful storms, as if the stuck weather pattern keeping this storm-delivering trough over the Eastern US for months, and as if the human-added atmospheric heat amping up the hydrological cycle and spurring more intense rain events were all not enough, we now have a large, moist tropical weather system moving in and threatening to become entangled in an already very wet pattern.

As of this morning, the National Hurricane Center had issued an advisory for a tropical system in the western Caribbean predicting a 60% likelihood of tropical storm formation over the next several days. The system is a large, sprawling and disorganized mass of thunderstorms and moisture moving toward the north-west at 10 to 15 mph. A circulation appears to be trying to form in a region near the densest thunderstorms. The system is predicted to move toward the northwest until it is eventually captured by the frontal boundary at the leading edge of our deeply sagging Jet Stream. Should this mix-up occur, a tropical weather system and potential tropical cyclone will have again combined with an Arctic originating air-mass over the Eastern US, setting the stage for a rather intense and widespread rainfall event.

If there are some reading this analysis and thinking that it rhymes somewhat with set up for Superstorm Sandy, they wouldn’t be entirely off the mark. Until recently, it was less likely that tropical systems would combine with polar originating air masses over the US. The troughs originated and faded rapidly, only infrequently coming into dramatic collisions. But now, with the Jet Stream increasingly settling into a stuck pattern (spurred by human caused warming and sea ice loss) and seeming to favor trough development over the continental US and not over the ocean, such collisions are far more likely.

With the current system, unlike Sandy, rain appears to be the primary concern for now — not storm hybridization, expansion, and superstorm development. These are not on the radar. But we are still very early in storm development and we don’t yet know how powerful the slowly organizing tropical system will become. What we have right now is a large, and potentially strengthening package of tropical moisture setting its sights on an already soaked US southeast.

Very Moist Developing Cyclone Setting Sights on Southeastern US.

Very Moist Developing Cyclone Setting Sights on Southeastern US.

(Image source: The National Hurricane Center)

So the risks at the moment are for a potential major flooding event on the five to seven day horizon as the tropical system continues to track northwestward until it is pulled into the stormy flow of the Jet Stream trough. At that point, it is predicted to dump a heavy load of moisture and rain over the US southeast.

Current predictions from NOAA reflect uncertainty in storm development and track and, at the moment, call for 3-5 inches of rainfall from the Gulf Coast States through Georgia and the Carolinas over the next 5-7 days. Local amounts, however, could be much higher, on the order of 8 inches or more. Such an event would intensify an already severe flood problem over this large area, likely resulting in major and widespread flooding.

NOAA rainfall predictions over the next week.

NOAA rainfall predictions over the next week.

(Image source: NOAA)

Any significant wind field of 40 mph or more would also likely result in a mass of fallen trees. The ground in this region is saturated with moisture, making it harder for tree root systems to grip the soil. So it takes much less wind to blow them down. Widespread power outages due to trees falling over power lines is, therefore, also a potential threat for this system.

Given the current position of the Jet Stream and uncertainty over potential storm strength and track, this situation could rapidly develop into a dangerous event for the southeastern US or we could end up with a storm system making landfall closer to Texas and Mexico. So we’ll be closely watching storm strength and path over the coming week.


Tropical weather system 92 L is starting to exhibit some cyclonic turning:

92 L Shows Cyclonic Turning

92 L Shows Cyclonic Turning



California Regional Weather Server

The National Hurricane Center

Read Jeff Master’s Assessment Here

Why Do I Call it a Mangled Jet Stream? Learn More Here.

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