Valid Friday August 01, 2014 to Tuesday August 12, 2014
US Hazards Outlook
NWS Climate Prediction Center College Park MD
EDT July 29 2014Synopsis
: A strong area of upper-level low
pressure is forecast to persist across the eastern U.S. through the end of July
before it begins to weaken. An area of upper-level high pressure is expected to
remain centered over the western U.S. A surface low is expected to cross
mainland Alaska this weekend. Hazards
Detailed Summary For Friday August 01 - Tuesday August 05:
- Much above-normal
temperatures for parts of the Pacific Northwest and Northern Intermountain
West, Fri-Tue, Aug 1-Aug 5.
- Heavy rain for coastal areas of the Southeast, Fri-Sun, Aug 1-3.
- Flash flooding possible for parts of the Southwest, Fri-Sun, Aug 1-3.
- Severe drought for parts of the Great Plains, Southwest, Pacific Northwest,
Great Basin, and California.
is likely to remain the major hazard across the Southwest as southeast flow
increases monsoon moisture and results in thunderstorms with locally heavy
rainfall through the weekend. The 6z GFS model indicates that the potential for
precipitable water values to exceed 1 inch across much of Arizona by Sunday.
Beyond the weekend, model solutions vary on whether the mid-level flow remains
southeasterly or becomes more westerly across the desert Southwest. In addition
to the flash flooding hazard, outflow from thunderstorms is capable of causing
blowing dust across southern Arizona.
Unseasonably low 500-hpa heights, enhanced low-level convergence along a
stationary front, and abundant moisture are expected to result in heavy
rainfall across coastal areas of the Southeast from Friday through at least
Maximum temperatures are forecast to average around 10 degrees F
below-normal across the southern Great Plains from Friday through Monday.
Meanwhile, the amplified ridge over the western U.S. is likely to maintain much
above-normal temperatures through at least Tuesday across the interior Pacific
Northwest and northern intermountain West. Numerous wildfires continue to burn
across these areas along with California, Nevada, and Utah. Currently, the
largest wildfire with nearly 400,000 acres burned is located in southeast
Oregon. A few dry thunderstorms could ignite additional wildfires across the
northern Great Basin and Pacific Northwest.
The coverage of showers is expected to increase across mainland Alaska by
early next week, but precipitation amounts are likely to remain below hazards
criteria. For Wednesday August 06 -
Tuesday August 12:
Spread amongst the 0z GFS ensemble members increases
regarding the amplitude of the ridge (trough) over the western (eastern) U.S.
during Week-2. A slight risk of above-normal temperatures for parts of the
Pacific Northwest on August 6 and 7 is posted on the Probabilistic Week-2
Hazards Outlook. This Week-2 hazard area is based on the potential that the
upper-level ridge may not weaken as quickly as forecast by the models. Also,
the slight risk is consistent with increasing spread among the 0Z GFS ensemble
As of 2pm EDT on Tuesday, a tropical wave is located near 10N/40W. This
well organized tropical wave should be monitored as it tracks into the central
Based on the latest Drought Monitor valid on July 22, severe to exceptional
drought continued to decrease and now covers 23.9 percent of the continental
Forecaster: Brad Pugh
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.