Valid Monday September 01, 2014 to Friday September 12, 2014
US Hazards Outlook
NWS Climate Prediction Center College Park MD
EDT August 29 2014Synopsis
: A cold front is forecast to move
across the northern tier of the lower 48 during the first half of next week.
High pressure is forecast over the Southeast and much of the southern Great
Plains during next week. Later next week, an upper-level system is forecast to
move from the Pacific Northwest to the northern Great Plains. A weak
low-pressure system is forecast to impact southern Alaska early in the outlook
period, followed by a rather tranquil period. Hazards
Summary For Monday September 01 - Friday
- Heavy rain from the Central Great Plains to the Great Lakes, Mon-Tue,
- Heavy rain for southern Texas, Tue-Wed, Sep 2-3.
- Heavy rain for the Upper Midwest, Thu, Sep 4.
- Heavy rain from the Northern and Central Great Plains to the Great Lakes,
Fri-Sat, Sep 5-6.
- Flooding in Montana, southwest Iowa, and northwest Missouri.
- Severe drought for the Central and Southern Great Plains, Southwest,
Pacific Northwest, Great Basin, and California.
A cold front is likely to traverse the northern tier of the
lower 48. Heavy rains (1-2 inches in 24 hours) are forecast to accompany the
front. The heaviest rains are likely from Kansas to Indiana. Isolated severe
thunderstorms are also possible over the same region, but no specific severe
weather threat area is designated as the spatial coverage of severe weather is
likely to be small.
That cold front is likely to stall across the middle of the CONUS, yielding
an increased threat for heavy rains through next week across the Central and
Northern Great Plains and Midwest. The most likely days are Sep 4, across the
Upper Midwest, followed by a larger area from the Plains to the Great Lakes,
associated with a more vigorous upper-level vorticity max during Sep 5-6.
A ridge is likely over the Southeast, resulting in slightly higher than
normal temperatures. Easterly flow and the impacts of a tropical easterly wave
are likely to result in heavy rains across South Texas during the middle of
next week. The National Hurricane Center has a 30% chance of development during
the next 5 days across the southern Gulf of Mexico.
The ECMWF and Canadian models also depict heavy rains over Florida on Sep
5, but uncertainty about location (between the ECMWF and Candian) and timing
(GFS is much later, GEFS mean has no signal) preclude the depiction of a hazard
at this time.
Given the recent heavy rains and forecast rainfall across the Northern
Great Plains, flooding is forecast to continue across Montana. The forecast
rainfall across the Central Great Plains and Midwest are likely to exacerbate
flooding in the Missouri River Basin during next week.
A weak low pressure system is forecast near the Alaska Panhandle. Rainfall
totals are likely to exceed 1 inch in 24 hours, but only very localized areas
are forecast to receive 2 inches or more in 24 hours, so no hazard is depicted.
A trough is likely to move across the Pacific Northwest during the later
portions of next week. Snow level levels are likely to drop to near 6500 feet
across the Northern Rockies during Friday. For Saturday September 06 -
Friday September 12:
Below normal temperatures are likely across the
Northern Rockies during this portion of the outlook. Slightly elevated odds of
much below normal temperatures are indicated where models have anomalies of
8-12 degrees F below normal, and the odds of being in the lowest 15th
percentile are more than 20%.
The most recent U.S. Drought Monitor, released on August 28, indicates the
percentage of CONUS in severe to exceptional drought decreasing very slightly
to 21.55 percent.
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.