Valid Saturday May 28, 2016 to Wednesday June 08, 2016
US Hazards Outlook
NWS Climate Prediction Center College Park MD
EDT May 25 2016Synopsis
: An area of upper-level low pressure
across the west-central CONUS is expected to gradually weaken during the next
week with a dissipating surface front over the Great Plains. A low pressure
system is expected to affect the coastal Southeast during the Memorial Day
weekend. An area of upper-level high pressure is likely to persist across
Alaska into the beginning of June. During Week-2, an area of upper-level high
pressure is expected to build across the northwestern CONUS with an area of
upper-level low pressure extending across the eastern and south-central U.S.
Summary For Saturday May 28 - Wednesday June 01:
- Locally heavy rain for the coastal Southeast,
Sat-Mon, May 28-30.
- Locally heavy rain for parts of the Great Plains and lower Missouri River
Valley, Sun-Tue, May 29-31.
- Locally heavy rain for parts of Texas, Wed-Thu, June 1-2.
- Much above normal temperatures for parts of the Great Lakes, Ohio Valley,
Central Appalachians, and Northeast, Sat, May 28.
- Flooding is occurring, imminent, likely, or possible across parts of the
Central and Southern Plains, central Rockies, lower Missouri River Valley, and
Midwest, Sat-Sun, May 28-29.
- A slight risk of much above-normal temperatures for parts of the Pacific
Northwest, Thu-Wed, June 2-8.
- Severe Drought across much of California and Nevada (and adjacent parts of
Arizona and Oregon), north-central Wyoming, and Hawaii.
Shortwave troughs ejecting from the longwave trough centered over the
Rockies is likely to trigger daily convection across the Great Plains through
the end of May. The most likely area and timing for locally heavy rainfall
(more than 1 inch per 24 hours) extends from the lower Missouri River Valley
south to northern Texas from May 29 to 31. On June 1, the risk for heavy
rainfall is expected to shift south across Texas where moist, southeasterly
flow interacts with a remnant front. Weakening flow at the mid-levels is
expected to become less favorable for widespread severe weather events across
the Great Plains.
Recent rainfall has resulted in minor to moderate flooding across parts of
the central U.S. and is likely to continue into the beginning of June. For
example, moderate flooding is forecast to persist along parts of the North
Platte River in Nebraska. Any heavy rainfall could exacerbate ongoing flooding
and may cause additional flooding due to the antecedent wetness.
Model guidance continues to indicate that a mid-level low and a weak
surface low with tropical origins approaches the Southeast coast during the
weekend. Regardless of intensity, locally heavy rain (more than 1 inch per 24
hours) is expected across the coastal Southeast from May 28-30. Due to weak
steering flow, the surface low is forecast to remain near the coastal
Southeast. Please refer to the National Hurricane Center for the latest updates
on this potential tropical or subtropical storm.
Strong ridging aloft is expected to result in much above-normal
temperatures across parts of the Northeast, eastern Great Lakes, and upper Ohio
Valley on Saturday, May 28. Maximum temperatures are forecast to average 10 to
15 degrees F above-normal across these areas with some locations likely
reaching 90 degrees F.
Unseasonably warm temperatures are likely to persist across much of Alaska
as ridging aloft remains dominant through the end of May. Although the 6Z GFS
ensemble mean indicates that temperatures will average more than 12 degrees F
above-normal across southwest Alaska, these temperatures are not considered to
be hazardous. For Thursday June 02 - Wednesday
The tail end of a surface front, a weakness in the subtropical
ridge, and abundant low-level moisture are likely to result in locally heavy
rainfall across parts of south-central Texas and the Rio Grande Valley on June
2. The deterministic 6Z/12Z GFS and 0Z ECMWF models indicate local rainfall
amounts near 2 inches within the area highlighted for heavy rainfall.
Elsewhere, the GFS ensemble mean indicates the potential for heavy rain along
the southern coast of Alaska but the ECMWF ensemble mean is weaker with the
The GFS and ECMWF ensemble means and their deterministic model runs depict
an increase in 500-hpa heights across the western conus by the beginning of
Week-2. A slight risk of much above-normal temperatures is posted for parts of
the Pacific Northwest where the GEFS reforecast tool indicates that daily
maximum temperatures have a 20 percent chance or more of exceeding the 85th
percentile and the potential exists for maximum temperatures to exceed 90
According to the U.S. Drought Monitor (issued May 19), severe, or greater
intensity, drought covers 4.07 percent of the U.S. Drought Monitor areas
(including Alaska, Hawaii, and Puerto Rico), down from 4.49 percent last week.
This is the lowest coverage since October 2010. A visual comparison between the
two latest U.S. Drought Monitor maps reveals one-category improvements in
portions of northern California (D2 to D1), western Nevada (D3 to D2), and Utah
(D1 to D0).
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.