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National Situation Update: Friday, April 20, 2007

Homeland Security Threat Level: YELLOW (ELEVATED).

National Weather

Northeast
Recovery from the recent Nor'easter will be assisted by a lack of rain and mainly clear conditions.  A large area of high pressure from the Great Lakes will result in warm air flowing into the region.  Temperatures across the majority of the Northeast will be in the 60s.  Flooding is still a concern.  Flood warnings are in effect for parts of New York, New Jersey and New England, with some rivers remaining above flood stage through today.

West
A Pacific system will bring rain to Southern California. Lower elevations could pick up between a tenth and three-quarters of an inch of rain while some mountain locations could receive up to 2 inches. The same storm will bring snow to the mountains above 5,000 feet and showers to the Nevada Great Basin.

Midwest
A few thunderstorms are expected across the Dakotas, Nebraska and Kansas later in the day.  A broad area of high pressure building into the east will allow the return of warmer temperatures.  A Southwest storm will bring severe thunderstorms across western Minnesota, southeast North Dakota, South Dakota, Nebraska, eastern Colorado and western Kansas on Saturday. Large hail, damaging wind gusts and isolated tornadoes will be a part of this outbreak.

South
A few showers are forecast for the Atlantic coast of south Florida.   The Southeast will be dry, worsening drought conditions.   A few strong thunderstorms will occur late in the day across western parts of Oklahoma and Texas. 

The storm system, currently over the central Appalachians, will not bring showers and thunderstorms to southern Alabama, southern Georgia or Florida. These areas are dry and the danger of wildfires is extremely high across the Southeast.  Red Flag Warnings are in effect across much of Florida.  (NOAA, National Weather Service, Media Sources)

Climate Models Suggest Warming-Induced Wind Shear Changes Could Impact Hurricane Development, Intensity

Wind shear is defined as a change in wind speed and/or direction within a short distance. It can be in either a horizontal or vertical direction, or both. This change causes a shearing or tearing effect.  Global climate model simulations for the 21st Century indicate a robust increase in vertical wind shear in the tropical Atlantic and East Pacific Oceans, which could act to inhibit the development or intensification of hurricanes in these regions. Historically, increased vertical wind shear has been associated with reduced hurricane activity and intensity.

While other studies have linked hurricane intensity to global warming, this is the first published study to indicate that changes to vertical wind shear seen in future climate projections would likely diminish the frequency and intensity of hurricanes.

"Wind shear is one of the dominant controls of hurricane activity, and the models project substantial increases in the Atlantic," said the lead author of the paper and a NOAA research oceanographer at the Geophysical Fluid Dynamics Laboratory (GFDL). "Based on historical relationships, the impact of the projected shear change could be comparable in magnitude as that of the warming oceans-with the opposite effect."
http://www.noaanews.noaa.gov/stories2007/s2840.htm

Tankers, Air Support Ready for Western Fire Season

The National Interagency Fire Center (NIFC) in Boise says that up to 35 heavy helicopters, 16 large air tankers, and single engine air tankers will be available to battle wildfires in the western United States this summer.

NIFC stated that Arizona's drought is a concern and the state, along with central and southern California, are in serious shape this early in the season.

El Nino was a no-show this year and has now flip-flopped into La Nina. These conditions melted snowpack nearly two months ahead of the norm.

Potential hurricanes could strain fire resources later in the year if the fire season extends into the fall and firefighters are needed in the Southeastern United States. (NIFC, media sources)

Tropical Weather Outlook

No new activity (FEMA HQ)

Earthquake Activity

Seven earthquakes ranging in magnitude from 5.3 to 6.1 occurred in the Southwestern Ryukyu Islands, Japan Region.  The first (magnitude 6.0) occurred at 8:26 pm EDT approximately 105 miles NNE of Ishigaki-jima, Ryukyu Islands, Japan at a depth of 31.3 miles.  The last six appear to be aftershocks occurring in the same general area.  The last earthquake occurred at 1:23 am EDT.  There are no reports of damage or injuries.  No tsunami warnings have been received.
(NOAA, USGS, Earthquake Hazards Program, Alaska Earthquake Information Center, Pacific Tsunami Warning Center, and West Coast/Alaska Tsunami Warning Centers)

Preliminary Damage Assessments

Connecticut: IA and PA PDAs have been requested.  Due to continued flooding of rivers, limited PA PDAs were scheduled to begin on April 19, 2007.

Massachusetts: IA PDAs for eight counties and PA PDAs for 5 counties are scheduled to begin on April 23, 2007.

New Jersey: IA and PA PDAs in an undetermined number of counties began on April 18, 2007.

New Hampshire: IA and PA PDAs in 10 counties to begin on April 19, 2007.

Vermont: Public Assistance PDAs in four counties began on April 19, 2007.

Rhode Island: PA PDAs for 5 counties are scheduled to begin on Monday, April 23, 2007. (FEMA HQ)

Wildfire Update

Current Situation: Wildland fire activity remains light throughout the states with 111 new fires reported. Four new large fires were reported: one each in Florida, North Carolina, Utah, and Minnesota. Four large fires were also contained: one in Georgia, two in North Carolina, and one in Minnesota.

Arkansas
Potato Hill (Ouachita National Forest): 1,079 acres. This Wildland Fire Use (WFU) incident was reported last week. The incident is located 14 miles west of Danville. This fire is being managed to accomplish natural resource objectives.

Florida
(NEW) Burns Lake (Big Cypress National Preserve): 300 acres at 10 percent contained. This fire is located eight miles east of Ochopee. Fire behavior included short fire runs, torching, and spotting.

Georgia
Sweat Farm Road (Georgia Forestry Commission): 22,000 acres at 35 percent contained. This fire started on private land 10 miles southeast of Waycross. It is burning in southern rough and timber. Fire behavior has moderated. A total of 22 structures were destroyed. Highways 84 and 122 remain closed.

(NEW) Knee Knocker Swamp (Georgia Forestry Commission): 2,000 acres at 70 percent contained. This fire is located two miles northwest of Nahunta. Fire behavior was reported as moderate.

Utah
(NEW) Virgin (Cedar City Field Office, BLM): 320 acres at 60 percent contained. This fire is one mile northeast of Virgin. The fire has rapidly spread through grass and brush.  (NIFC)

Disaster Declaration Activity

The Governors of New York, Maine, and West Virginia have requested major disaster declarations as a result of severe storms and flooding caused by the recent April Nor'easter. (FEMA HQ)

Last Modified: Thursday, 04-Jun-2009 16:52:11 EDT