U.S. Hazards Outlook - Made
Jul 25, 2016
|Day 3-7 Outlook
||Day 8-14 Outlook
||Day 8-14 Probabilistic Temperature Hazards
Valid Thursday, July 28, 2016 to Monday, August 08, 2016
Summary of Forecasts and Hazards
US Hazards Outlook
NWS Climate Prediction Center College Park MD
EDT July 25 2016Synopsis
: At the beginning of the forecast
period a pair of surface fronts are expected to be relatively stationary across
the Great Lakes and Mid Atlantic where they are expected to remain for the
majority of week-1. By late in the week some minimal progression of the
pattern may shift these only slightly south and east of the region. Mid-level
high pressure is expected to dominate the west during week-1 before shifting
eastward during week-2. A cold front is forecast to drop southeast across
Alaska during week-1 before an anticipated shift to mid-level high pressure
during week-2. Hazards
Summary For Thursday July 28 - Monday August 01:
- Heavy rain across portions of the
Upper Mississippi Valley and Great Lakes, Thu, Jul 28.
- Heavy rain across portions of the Mid-Atlantic, the Lower Mississippi
Valley, the Central Appalachians, the Tennessee Valley, the Middle Mississippi
Valley, the Northeast, and the Ohio Valley, Thu-Fri, Jul 28-Jul 29.
- Heavy rain across portions of Central Alaska, Fri-Sun, Jul 29-31.
- Excessive heat across portions of the Southeast and the Mid-Atlantic,
Thu-Sun, Jul 28-Jul 31.
- Much above normal temperatures across portions of the interior Northeast,
Thu, Jul 28.
- Much above normal temperatures across portions of the Central Great Basin,
the Northern Plains, the Northern Rockies, the Central Rockies, California, the
Northern Great Basin, the Pacific Northwest, and the Southwest, Thu-Sat, Jul
- Moderate risk of much above-normal temperatures for portions of the Great
Lakes, Tue-Wed, Aug 2-Aug 3.
- Slight risk of much above-normal temperatures for portions of the Central
Plains, the Northeast, the Northern Plains, the Middle Mississippi Valley, the
Mid-Atlantic, the Upper Mississippi Valley, the Great Lakes, and the Ohio
Valley, Tue-Fri, Aug 2-Aug 5.
- Slight risk of much above-normal temperatures for portions of the Southeast
and Mid-Atlantic, Tue-Sun, Aug 2-Aug 7.
- Severe Drought across the Mid-Atlantic, the Lower Mississippi Valley, the
Central Great Basin, the Northern Plains, the Tennessee Valley, Hawaii, the
Northeast, California, the Southern Appalachians, the Southeast, the Central
Appalachians, the Great Lakes, and the Southwest.
Much above-normal temperatures are forecast to continue for portions of
the Northeast through the outset of the forecast period, with expectations of
maximum temperature anomalies exceeding 8 degrees F on July 28. Further south,
excessive heat is possible July 28-31 across interior portions of the Carolinas
where comparable maximum temperature anomalies are forecast, with expectations
of overnight lows being near 80 degrees F and heat index values exceeding 105
Further to the west, heavy rainfall (exceeding 1" in 24 hours) is forecast
across portions of the Middle Mississippi Valley and Great Lakes on July 28
where Mesoscale Convection System activity may build over top of the ridge.
However, the primary focus for heavy rainfall is expected on July 28-29 further
south and east stretching from the Southern Mississippi Valley northeast
through Southern New York associated with the primary stationary front. The
GEFS is generally further south with this precipitation, while the ECMWF
ensembles are focus precipitation through the Mid-Atlantic. This boundary is
expected to linger across this region for the remainder of week-1, although
uncertainty around position and shortwave timing limits any further hazards
The heat focus in week-1 will shift from the east to across the west, with
a 594 dm 500-hPa ridge expected across the Great Basin early in the forecast
period. A broad region of much above-normal temperatures are forecast for July
28-30 where maximum temperature anomalies could exceed 8 degrees F. Hazards
associated with this shape are expected to shift north and east over the course
of week-1. Anticipated deamplification of the flow by July 31 limits any
further heat hazard depiction. Increased dry thunderstorm chances are also
anticipated across portions of the Great Basin and Northern Intermountain
Region on July 29-30, however current forecast probabilities fall below
criteria for depiction on the forecast map.
A cold front is forecast to drop south across Alaska during week-1, with
the GFS being further south and more progressive relative to the ECMWF which is
slower and keeps the boundary further north. While precipitation amounts
should generally be below the 2" of rain in 24 hours criteria used for Alaska
during July 29-31, antecedent wet conditions may lead to flooding concerns
associated with this frontal passage, thus resulting in a hazard
depiction. For Tuesday August 02 - Monday
For week-2, ridging is generally forecast across the Central
CONUS, with the strongest positive 500-hPa height anomalies favored through the
Great Lakes during the early part of the forecast period. A moderate risk of
much above-normal temperatures is co-located with these expected strongest
height anomalies for August 2-3. A slight risk of much above-normal
temperatures extends from the Upper Mississippi Valley through the Great Lakes
to interior New England for August 2-5. The GEFS probabilistic extremes tool
highlights these two areas as exceeding 40% and 20% during the respective
periods mentioned. ECMWF ensembles also feature the heat for this area, albeit
a bit further south than the GEFS.
A second region highlighted for a slight risk of much above-normal
temperatures is across portions of the Southeast for August 2-7. Both the GEFS
and ECMWF reforecast tools highlight this region for likelihood of much
above-normal temperatures during the 8-14 day period. The GEFS probabilistic
extremes tool also isolates this region for having a 20% chance of exceeding
the 85th percentile of climatological maximum temperatures during the
According to the U.S. Drought Monitor (USDM), released on July 21, severe,
or greater intensity, drought covers 5.68 percent of the U.S. Drought Monitor
areas (including Alaska, Hawaii, and Puerto Rico), an increase of a half
percent since the previous week. This increase is due to an expansion of
short-term severe drought east of the Rockies.
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.