Valid Monday May 25, 2015 to Friday June 05, 2015
US Hazards Outlook
NWS Climate Prediction Center College Park MD
EDT May 22 2015Synopsis
: A warm, humid pattern is forecast to
dominate over parts of the eastern U.S. during much of the period, while an
active pattern is forecast to continue over the nation's midsection.
Upper-level high pressure is expected to persist over Alaska during the next
two weeks, while a gradual warming trend is forecast over the western U.S.
early in the period. Hazards
For Monday May 25 - Friday May 29:
- Heavy rain from
southeastern Texas through the lower Mississippi Valley, Mon-Tue, May 25-26.
- Heavy rain for parts of the central and southern Plains, Wed-Thu, May 27-28.
- Much above-normal temperatures are expected for parts of the Mid-Atlantic
and Northeast U.S., Tue-Fri, May 26-29.
- Flooding is possible, imminent, or occurring in parts of the central and
southern Great Plains region.
- Enhanced wildfire risk for interior eastern Alaska, Mon-Fri, May 25-June 5.
- Slight risk of much above-normal temperatures for the Mid-Atlantic U.S.,
Sat, May 30.
- Severe drought for parts of the northern, central and southern Great
Plains, Upper Mississippi Valley, Southwest, Great Basin, California, and the
During this period, an amplified
upper-level trough is forecast to lift northeastward out of the west-central
CONUS while weakening, while robust upper-level ridging is forecast to persist
near the East Coast. Surface low pressure associated with the former is
expected to move quickly northeastward toward the Great Lakes, producing heavy
rain in the warm sector across southeastern Texas and the lower Mississippi
Valley. Precipitation amounts of 1-4 inches are forecast for the area depicted
on the map over a 2-day period.
Given recent heavy rainfall over the central and southern Plain, with more
anticipated even before the start of this period, saturated soils will
undoubtedly lead to flooding areas. Other small areas of flooding are depicted
in parts of Colorado and Nebraska. Due to the frequent and often rapid changes
in flood areas designated on the Hazards map, it is recommended that residents
consult the very latest information at the River Forecast Center (RFC) homepage
A weaker shortwave is forecast to move through the mean trough centered
near the Rockies later in the period. This is expected to trigger another round
of locally heavy rainfall for parts of the central and southern plains by next
Wednesday and Thursday. There is still a fair amount of uncertainty with this
feature, so it will be important to monitor the next hazards update on Monday
for the latest information.
Strong to severe thunderstorms may also develop during this period across
central and southern portions of both the Plains and Mississippi Valley. Fairly
poor run-to-run continuity among various dynamical models, regarding the timing
of individual short-wave features expected to move through this region,
precludes the designation of a severe weather area on the map at this time.
As an upper-level ridge builds over the Southeast Coast, hot and humid
conditions are forecast to return to parts of the eastern CONUS during the
period. High temperatures could exceed 90 degrees for three or more consecutive
days over the depicted region, following a warm frontal passage on Monday. The
hazard is depicted over the region where maximum daytime temperatures are
forecast to be greater than 10 degrees above normal and approach or exceed 90
In the eastern interior of Alaska, continued warm, dry, and breezy
conditions favor an increased chance of critical wildfire conditions throughout
this period, as well as the ensuing Week-2 period. For Saturday May 30 - Friday
The expected mid-tropospheric flow pattern for Week-2 features an
amplified ridge over western Canada and Alaska, and a deep trough over eastern
northeastern Canada. A less-amplified pattern is predicted over the CONUS
(especially compared to higher latitudes), with a climatological trough
centered over California, and quasi-zonal flow downstream over the remainder of
The enhanced risk of wildfires noted for eastern interior Alaska during the
3-7 day period is likely to extend throughout most, if not all, of Week-2. Well
above-average temperatures and below-median precipitation are anticipated
during this period, associated with the predicted persistence of an anomalous
Warm and humid conditions are more than likely going to persist across
parts of the eastern CONUS, at least early in the period, where a slight risk
of much above-normal temperatures is indicated over the Mid-Atlantic.
The most recent U.S. Drought Monitor, released yesterday, indicates a
substantial decrease (from 17.68 to 15.16) in the percentage of the CONUS in
severe to exceptional drought (D2-D4).
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.