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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Quoting cmahan:
The problem with the ignore button is that then you can't report the comments. *clickety-click-click*

clicked like 20 times already...finally hit ignore...waste of space and time
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Quoting cmahan:
The problem with the ignore button is that then you can't report the comments. *clickety-click-click*

I reported him several times. He'll be yanked and hopefully banned very soon.
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getting closer
Member Since: September 18, 2010 Posts: 0 Comments: 7127
Time: 18:36:00Z
Coordinates: 22.9667N 88.4W
Acft. Static Air Press: 978.2 mb (~ 28.89 inHg)
Acft. Geopotential Hgt: 290 meters (~ 951 feet)
Extrap. Sfc. Press: 1011.1 mb (~ 29.86 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 35° at 10 knots (From the NE at ~ 11.5 mph)
Air Temp: 24.6°C (~ 76.3°F)
Dew Pt: 16.1°C (~ 61.0°F)
Peak (10s) Flt. Lvl. Wind: 10 knots (~ 11.5 mph)
SFMR Peak (10s) Sfc. Wind: 13 knots (~ 14.9 mph)
SFMR Rain Rate: 0 mm/hr (~ 0 in/hr)
Member Since: September 18, 2010 Posts: 0 Comments: 7127

Complete Update


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Looks like two centers again.One in the Caribbean and one in the gulf...
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The problem with the ignore button is that then you can't report the comments. *clickety-click-click*
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Quoting txalwaysprepared:
Sadly, I would love for 90L to come here (hitting in the same spot as Hurricae Ike did). We need the rain so very badly!!!!

Agreed. Just don't push that massive surge that Ike did.
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601. j2008
Be back after all the spamming is over.
Member Since: December 19, 2008 Posts: 1 Comments: 224
I think thats a very BAD way for someone to blog here.

Member Since: July 3, 2005 Posts: 449 Comments: 140039
will someone plz help me report this bozo for wasting blog space?
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Time to hit the ignore button on those quotes and just keep moving on folks....We have a storm on our hands.
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And the blog is infested by trolls again :/
Member Since: August 2, 2010 Posts: 0 Comments: 5278
Quoting bigwes6844:
I saw that funnel pat. It didnt look impressive to me but i thought i saw something swirling around. it was lightning like crazy out here. Im in new orleans east pat not to for from where it was.
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.
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Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather

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