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

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

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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.

Angela

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Quoting nrtiwlnvragn:
invest_RENUMBER_al902011_al042011.ren 27-Jul-2011 19:17 3.8K


Seriously?
Member Since: May 27, 2009 Posts: 0 Comments: 4438
Quoting WxLogic:
Definitely TS Don... 48MPH at the SFC

Time: 19:10:00Z
Coordinates: 21.7167N 86.7167W
Acft. Static Air Press: 973.4 mb (~ 28.74 inHg)
Acft. Geopotential Hgt: 320 meters (~ 1,050 feet)
Extrap. Sfc. Press: 1010.2 mb (~ 29.83 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 216° at 31 knots (From the SW at ~ 35.6 mph)
Air Temp: 19.0°C (~ 66.2°F)
Dew Pt: 13.1°C (~ 55.6°F)
Peak (10s) Flt. Lvl. Wind: 31 knots (~ 35.6 mph)
SFMR Peak (10s) Sfc. Wind: 42 knots (~ 48.3 mph)
SFMR Rain Rate: 23 mm/hr (~ 0.91 in/hr)
(*) Denotes suspect data


Probably a gust, though.

Not much other data saying it's a TS yet. Most winds are in the 35mph bracket, but there's further recon to go.

Looks like we've got TD4 confirmed at the least.
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Taz do you think that this storm has a chance at hurricane status?
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AL, 04, 2011072718, , BEST, 0, 223N, 873W, 30, 1008, TD, 34, NEQ, 0, 0, 0, 0, 1011, 110, 30, 40, 0, L, 0, , 0, 0, INVEST, M,
Member Since: Posts: Comments:
1162. jpsb
Quoting WxLogic:
I guess RitaEvac is now spamming. :(
WTF! I was hoping to get some info on the developing storm. I live right on Galveston Bay and if I need to take action I require a couple of days to do so. Spaming this blog with a storm in the gulf is really low class.
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AL, 04, 2011072718, , BEST, 0, 223N, 873W, 30, 1008, TD,
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1160. nigel20
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So RitaEvac is predicting that ToddAndrews will make landfall between Galveston and Corpus Christi?
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1156. Grothar
There is no reason they will not go directly to Tropical Storm status.
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1155. angiest
Quoting HurricaneHunterJoe:
do they use durface or flight level for their wind parameters?


They may use flight level as a proxy if they don't have a good feel for surface (based on instruments, dropsondes, and visual observations). 45mph flight winds will not result in a naming (barring locating surface winds of >=39mph).

They use surface winds for naming, category, etc.
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1152. WxLogic
Definitely TS Don... 48MPH at the SFC

Time: 19:10:00Z
Coordinates: 21.7167N 86.7167W
Acft. Static Air Press: 973.4 mb (~ 28.74 inHg)
Acft. Geopotential Hgt: 320 meters (~ 1,050 feet)
Extrap. Sfc. Press: 1010.2 mb (~ 29.83 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 216° at 31 knots (From the SW at ~ 35.6 mph)
Air Temp: 19.0°C (~ 66.2°F)
Dew Pt: 13.1°C (~ 55.6°F)
Peak (10s) Flt. Lvl. Wind: 31 knots (~ 35.6 mph)
SFMR Peak (10s) Sfc. Wind: 42 knots (~ 48.3 mph)
SFMR Rain Rate: 23 mm/hr (~ 0.91 in/hr)
(*) Denotes suspect data
Member Since: August 14, 2008 Posts: 4 Comments: 5038
invest_RENUMBER_al902011_al042011.ren 27-Jul-2011 19:17 3.8K
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Quoting Daveg:

Re:


Getting harder to argue against a middle-TX coast landfall. All of the dynamical models calling for about the same thing, there. (Not even a GFS ensemble member down towards Mexico.)
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1145. tkeith
Quoting NotCircumventing:
It's a good thing all those funny people got banned, huh?

I think we will see Don at 5, as opposed to TD4.
TD at 11...wait that's Cosmics line
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think the lowest pressure is 1006mb and change so far
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Hey Levi some of the models such as the HWRF have developed 90L as a moderate TS and moving it further North could this mean that the high pressure that would steer a deeper storm may be sliding to the east more and opening up the door for a more NW movement?
Member Since: August 29, 2006 Posts: 22 Comments: 1352
Quoting hydrus:
That is why I hope dry air kills it...I checked the 10 day model runs, and I was concerned with not only the path the wave is forecast to take, but the weakening of the Bermuda High, and what appears to be almost complete disappearance of high pressure areas over the United States. You probably already saw this..Link


Can you explain what the link means?

Florida and the East Coast more at Risk?

Im learning
Member Since: July 21, 2011 Posts: 1 Comments: 332
Quoting KittieCane:
Is that the full recon report or is there more data to come?



they this started so there is a lot more too come
Member Since: May 21, 2006 Posts: 5091 Comments: 115456
Quoting Hurricanejer95:
Time: 19:07:30Z
Coordinates: 21.8N 86.8333W
Acft. Static Air Press: 974.3 mb (~ 28.77 inHg)
Acft. Geopotential Hgt: 300 meters (~ 984 feet)
Extrap. Sfc. Press: 1009.1 mb (~ 29.80 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 250 at 38 knots (From the WSW at ~ 43.7 mph)
Air Temp: 20.2C (~ 68.4F)
Dew Pt: 14.7C (~ 58.5F)
Peak (10s) Flt. Lvl. Wind: 39 knots (~ 44.8 mph)
SFMR Peak (10s) Sfc. Wind: 22 knots* (~ 25.3 mph*)
SFMR Rain Rate: 17 mm/hr* (~ 0.67 in/hr*)

Recon found 45 mph winds
do they use surface or flight level for their wind parameters? i always thought measured surface winds.
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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