Valid Monday September 22, 2014 to Friday October 03, 2014
US Hazards Outlook
NWS Climate Prediction Center College Park MD
EDT September 19 2014Synopsis
: An area of upper-level low
pressure is forecast to progress into the western U.S. later next week, while
an area of upper-level high pressure builds across the east-central U.S. On
Monday and Tuesday, an area of upper-level low pressure is expected to slowly
track from the north-central Rockies to the Great Plains. A front is forecast
to become stationary across south Florida by mid-week. Surface high pressure is
expected to build across Alaska as the North Pacific storm track shifts south.
Detailed Summary For Monday
September 22 - Friday September 26:
- Locally heavy rain for the central/southern
Great Plains, Mon-Tue, Sep 22-23.
- Severe drought for the Central and Southern Great Plains, Southwest,
southern Georgia, Pacific Northwest, Great Basin, and California.
The high resolution models are in
reasonably good agreement early in the period that a mid-level trough slowly
emerges from the Rockies and moves across the Great Plains. Southerly flow on
the back side of a surface high is expected to spread anomalous moisture north
across the Great Plains. This mid-level trough coupled with abundant low-level
moisture is expected to result in locally heavy rainfall, most likely across
the central/southern Great Plains, on Monday and Tuesday.
An upper-level ridge is expected to result in maximum temperatures
averaging around 12 degrees F above-normal across the interior Pacific
Northwest on Monday. The anomalous warmth is forecast to shift east to the
northern high Plains by mid-week. Since maximum temperatures are forecast to
remain below 90 degrees F across these areas, a much-above normal temperature
hazard is not deemed necessary.
Numerous wildfires are burning across the Pacific Northwest and California
with the largest wildfire (more than 125,000 acres burned as of September 19)
in Siskiyou County of northern California. During the middle part of next week,
the high resolution models remain consistent that a trough with southwest flow
aloft affects the Pacific Northwest and northern California which would bring
much needed rain to these areas. A heavy rain hazard is not posted since the
high resolution models indicate rainfall amounts below hazards criteria.
Surface high pressure is forecast to become centered over the Northeast by
mid-week, while a front becomes stationary from the Gulf of Mexico east to the
northern Bahamas. The potential exists for surface low development along this
front near the Southeast Coast. The exact evolution of this feature is unclear
due to model inconsistencies leading to low predictability.
Following a wet weekend across the Alaska Panhandle, a drying trend is
expected due to a southward shift of the north Pacific storm track. A surface
ridge is forecast to prevail across most of Alaska during this period.
Saturday September 27 - Friday October 03:
Ensemble means indicate a
pattern change by Week-2 with a trough (ridge) over the western (eastern)
conus. Near to above-median precipitation is expected to accompany this trough
as it moves inland across the western U.S. However, no heavy precipitation
(rain or high-elevation snow) is anticipated at this time across the western
The U.S. Drought Monitor, valid on September 16, indicates that the
percentage of the CONUS in severe to exceptional drought decreased below 20
percent for the first time since January 2014.
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.