Valid Thursday August 06, 2015 to Monday August 17, 2015
US Hazards Outlook
NWS Climate Prediction Center College Park MD
EDT August 03 2015Synopsis
: A frontal system is forecast to move
eastward across the northern CONUS during the 3-7 day Outlook period, weakening
as it approaches New England. A cold front is predicted to move deep into the
Southeast, and gradually become stationary. These two systems are expected to
be the main producers of precipitation during the 3-7 day period across the
contiguous U.S. Tropical storm Guillermo, currently located over the
east-central tropical Pacific Ocean, is forecast to pass close to, perhaps just
north of, the Hawaiian Islands at the beginning of the Outlook period. A fairly
large low pressure system is anticipated to affect southwestern and southern
Summary For Thursday August 06 - Monday August
- Heavy rain for the Ohio and Tennessee
Valleys, mid-Atlantic region, and southern New England, Thu-Fri, Aug 6-7.
- Heavy rain for portions of Kansas and Missouri, Thu-Fri, Aug 6-7.
- Periods of heavy rain across much of the Dakotas and Minnesota, Thu-Sun,
- Heavy rain for Iowa and Illinois, Sat-Sun, Aug 8-9.
- Heavy rain for northern Florida and southern Georgia, Sat-Sun, Aug 8-9.
- Severe drought for parts of the western third of the CONUS, southern
Georgia, southern Florida, North Carolina and Hawaii.
- Slight chance of much above-normal temperatures across the southern Plains
and lower Mississippi Valley, Tue-Thu, Aug 11-13.
As a low pressure center moves across the mid-Atlantic region and off
the Northeast coast, the trailing cold front is forecast to move into the deep
South, before becoming stationary. Showers and thunderstorms are expected
across much of this region, though the best chances for heavy rain (1-2 inches)
extend from eastern sections of both Kentucky and Tennessee generally
northeastward to include much of the mid-Atlantic and southern New England.
Another area that is anticipated to receive comparable rainfall amounts is
northeastern Kansas and western Missouri. Several days later, relatively
small-scale areas of heavy rain are anticipated over portions of the Midwest,
and northern Florida and southern Georgia. Periods of heavy rain are forecast
for the Dakotas and Minnesota during most of this period, though this is
largely due to an approaching frontal system from the northern Rockies. At the
present time, no areas of severe weather are highlighted, for any of the region
generally encompassing the northern and central Plains, the middle Mississippi
Valley, and the Tennessee/Ohio Valleys. The main reason for this is the
expectation of outflow boundaries associated with overnight thunderstorm
clusters (MCS's), and their tendency to stabilize the boundary layer the
following afternoon. These outflow boundaries make it very challenging to
pinpoint where subsequent convection may develop.
According to the USDA Forest Service, there are nearly 2 dozen large
wildfires in progress across the West Coast states, with the greatest
concentration of wildfires in California. Fires in the northwest area of
California (generally near or in the coastal mountains) have burned anywhere
from 3000 to 54000 acres, as of today. These wildfires appear to be related to
stronger winds associated with a 500-hPa trough near the coast, and the
presence of dry vegetative fuels in this region.
Tropical Storm Guillermo is currently (5am Hawaiian Standard Time) located
about 630 miles east-southeast of Hilo, HI, moving slowly toward the Hawaiian
archipelago. It is a strong tropical storm, with maximum sustained winds of 70
mph. Dynamical model guidance predicts Guillermo will pass close to the Islands
just prior to, and during the first two days of, the beginning of this period.
The official track, issued by the Central Pacific Hurricane Center (CPHC) in
Honolulu, has Guillermo passing just north of Hawaii as a still-potent tropical
storm. Residents across the 50th state are encouraged to obtain the very latest
information on this storm by consulting local news media, and/or the CPHC at:
A fairly large low pressure system is predicted to move eastward across the
southern coast of Alaska during this period, bringing clouds and precipitation.
However, at this time, no weather-related hazards are expected with this
system. For Tuesday August 11 - Monday
By the end of the 3-7 day period, and into at least the first
half of Week-2, the highest 500-hPa heights associated with the subtropical
ridge are forecast to shift from the Southwest into the southern Great Plains
region. This favors a slight risk of much above-normal temperatures across the
south-central CONUS. Mid-tropospheric troughs are anticipated near the Pacific
Coast, and the Atlantic Coast states.
The latest weekly U.S. Drought Monitor map, released on July 30th, shows a
slight increase in the coverage of severe to exceptional drought (D2 to D4)
across the contiguous U.S., from 16.74 percent to 17.17 percent. According to
AHPS, rainfall has been below-normal during the past two weeks for most areas
east of the Mississippi River, though with one significant exception. For most
of the northwest quarter of the Florida peninsula, rainfall amounts have ranged
from 5-8 inches above normal, and even higher in some localized areas. This is
associated with a weak area of low pressure over northern Florida. In contrast,
southern Florida is running a 1-3 inch rainfall deficit during the last 14
Forecaster: Anthony Artusa
Click here to see a display of the GFS Ensemble Forecasts
Please consult local NWS Forecast Offices for short range forecasts and region-specific information.