Drought continues; Yellowstone fires could become more frequent; 90L set to develop

By: Dr. Jeff Masters , 3:58 PM GMT on July 27, 2011

Southern Drought Continues

Temperatures continue to soar into triple digits in the Southern Plains this week, and are expected to remain well above average for at least the next month. High air temperatures and low humidity (because of the low soil moisture) will continue to maintain drought conditions in the South unless we see some Gulf-landfalling tropical cyclones—a good remedy for a such an extreme drought.

This year's drought in the South is unprecedented by many definitions. Last year at this time, 0% of the contiguous U.S. was in exceptional drought. Last week, the exceptional drought region covered 11.96%. The area of contiguous U.S. in exceptional drought conditions has never been this high since the Drought Monitor record started in 2000. The highest it had been before June of this year was 7.85% in August of 2002.

Figure 1. Temperature anomaly (difference from average) in degrees Celsius for the period July 1 through July 25 (top) and soil moisture anomaly in millimeters (bottom) on July 25 (from the Climate Prediction Center).

In late June, the U.S. Department of Agriculture designated 213 counties in Texas (84% of the state) as primary natural disaster areas. As I mentioned yesterday, the Texas drought and wildfires are one of the nine billion-dollar disasters of 2011 so far. The National Climatic Data Center estimated that this event had cost up to $3 billion as of June 16. This number is surely rising every day that the South doesn't see rain.

New study concludes Yellowstone wildfires could become more frequent

In a study published this week by the Proceedings of the National Academy of Sciences, researchers have concluded that global warming could have a serious impact on the severity and frequency of wildfires in the Yellowstone region (an area where the states of Montana, Idaho, and Wyoming come together). Historically in this region, fewer than 5% of wildfire occurrences account for 95% of the total area burned. But in a global warming scenario, they found that fire activity could become more severe and more frequent, causing the ecosystem to change dramatically.

Using climate conditions and historical fire data from 1972 to 1999, it was possible to link certain environmental thresholds (temperature, humidity, etc) to past wildfire events. Then by employing the output of various climate models, fire frequency can be forecast well into the future. Figure 2 illustrates the result from one of the climate models they used in the study, and the upward trend of fire activity over the next 100 years. In 1988, a particularly hot and dry year, 36% of the park burned. The study uses this year as a baseline to compare future events.

Figure 2. Figure 2B from the manuscript. Observed burn area (blue line) median of predicted area burned (black dotted line), and ranges (light and dark orange) aggregated over the Yellowstone area defined by the study by Westerling et al. (Source).

What was once a low-probability event could become a high-probability event by mid-century. Fires that have only happened every 100 to 300 years in the past could now be occurring every 30 years in the future. The results of this research has implications for sub-alpine forests across the globe. Warming temperatures and decreasing humidity will lead to more wildfires, and will cost billions of dollars to fight them, if we choose to do so.

Invest 90L

90L has moved west overnight and looks ripe to develop today. While the upper level circulation (500 mb) is very much displaced, the lower level circulation looks strong and coherent through the system's mid-levels (850 and 700 mb). Thunderstorm activity continues to organize, and it appears that a surface circulation is developing. Moisture remains high in the system (around 4.5 g/kg specific humidity) and wind shear should be somewhat favorable as it crosses through the Gulf of Mexico. In terms of track, the statistical models have generally been favoring a Brownsville landfall scenario, but the dynamical models have been inching north over the past day or so. The HWRF is in line with the ECMWF deterministic today, with landfall near Corpus Christi.

The Hurricane Hunters have a mission scheduled for 18Z today (2pm EDT) to investigate whether or not 90L has a closed surface circulation. If it does, given the amount of organized convection and moderate wind speeds (around 34 mph in the latest invest update), the Hurricane Center will probably call this system at least Tropical Depression Four.

If 90L develops this afternoon, I will have another update to look at track and intensity forecasts.


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674. beell
Looks pretty weak based on recon so far. Not much of a pressure gradient.
Member Since: Posts: Comments:
Quoting Orcasystems:

Taz.. stop it.. your being baited... everyone else is ignoring him... and your quoting the idiot.

well do could t help it lol
Member Since: May 21, 2006 Posts: 5100 Comments: 117338
UK MET Office




-------------- -------- -------- --------

12UTC 27.07.2011 21.7N 86.7W WEAK

00UTC 28.07.2011 22.4N 87.7W WEAK LITTLE CHANGE

12UTC 28.07.2011 22.9N 90.0W WEAK LITTLE CHANGE

00UTC 29.07.2011 24.3N 92.5W WEAK LITTLE CHANGE

12UTC 29.07.2011 25.7N 94.6W WEAK LITTLE CHANGE

00UTC 30.07.2011 26.1N 96.8W WEAK WEAKENING SLIGHTLY


Member Since: Posts: Comments:
Quoting palmbaywhoo:
Someone didn't pay a bill lol

Member Since: May 21, 2006 Posts: 5100 Comments: 117338
Quoting Tazmanian:

you been reported

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Quoting MrstormX:

Literally right on the border...wow

I've got the fans out, trying to push some of that LA rain West into SE TX.
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Quoting atmoaggie:
That must have prompted this most unusual special weather statement from NWS NOLA:

...Tropical funnel clouds possible today...

An extremely tropical and moist airmass remains in place across
the area today. In addition...this mornings upper air sounding
shows very little in the way of low level winds. This type of
environment is favorable for the development of tropical funnel
clouds. Tropical funnel clouds will be most likely across the
southshore and near bodies of water.

These tropical funnels typically form and dissipate quickly and
most do not reach the ground. However...a few may briefly make
contact in mainly marshy areas. If any funnel cloud that develops
becomes more defined or appears as though it will reach the
ground...a Tornado Warning will be issued.

atmo: I've never seen one for this before.
Yeah i heard the radio was going off with the emergency system to tell you something coming. It was about 3 or 4 miles north of me. Really didnt look too serious when i saw it.
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Quoting Tazmanian:

you been reported

Taz.. stop it.. your being baited... everyone else is ignoring him... and your quoting the idiot.
Member Since: October 1, 2007 Posts: 81 Comments: 26525
Member Since: July 3, 2005 Posts: 439 Comments: 137186
Someone didn't pay a bill lol
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I wonder if DonL is being influenced byy the weakness over the eastern seaboard. The CONUS high centered over TN/KY has weakened considerably and the latest steering suggests a significant northerly component for Don.

here is current lvl:

and next higher lvl steering:

note the weakness up the southeast coast
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Member Since: Posts: Comments:
As of the last observation at 18:37:30Z, the plane's...

Direction of Travel: SE (137°)
Location: 156 miles (250 km) to the NW (322°) from Cancún, Quintana Roo, México.
Member Since: September 18, 2010 Posts: 0 Comments: 6866
If storm goes to Upper TX coast, most of TX not gonna get anything, Coastal bend (central coast) is the only hope, but I got news, most of TX is not gonna get rain from this vort system. Hopefully I'm wrong
Member Since: July 14, 2008 Posts: 2 Comments: 10137
Quoting quakeman55:

I reported him several times. He'll be yanked and hopefully banned very soon.

As did I, what a pathetic thing.
Member Since: May 27, 2009 Posts: 0 Comments: 4454
Quoting Patrap:

540. DocNDswamp

Hiya Doc,,Im sure you remember the 05 Cindy that sputtered then had a good 48 hr run to Cat-1 off the Yucatan.

hey pat i saw that funnel you was talking about im near bullard in new orleans east
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Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather

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