Valid Monday March 27, 2017 to Friday April 07, 2017
US Hazards Outlook
NWS Climate Prediction Center College Park MD
EDT March 24 2017Synopsis
: During the first few days of the
Outlook period, several waves of low pressure are predicted to track
northeastward along a cold front that is initially forecast to extend from the
southern Plains to the eastern Great Lakes region. The front is expected to
stall as it reaches the deep South several days later. On March 30th, this
front is anticipated to begin moving northward as a warm front, which extends
westward to a developing low pressure center over the southern Plains. This
developing Low is then forecast to track northeastward towards the Ohio Valley
and eastern Great Lakes region. The anticipated passage of several frontal
systems across the West during this Outlook period is expected to bring
additional precipitation, especially to the Pacific Northwest. In Alaska,
several areas of weak low pressure are projected to influence the southern
portions of the state. A more significant storm system may affect the Aleutians
and Alaska Peninsula about a week from now. Hazards
Detailed Summary For Monday March 27
- Friday March 31:
- Severe Weather for parts of the Lower Mississippi and Lower Tennessee
Valleys, Mon, Mar 27.
- Severe Weather for west-central Texas and nearby parts of extreme southern
Oklahoma, Tue, Mar 28.
- Severe Weather for eastern portions of the southern Plains, and the Lower
Mississippi Valley, Wed, Mar 29.
- Periods of locally heavy rain for central and southern portions of both the
Great Plains and Mississippi Valley, extending eastward into Alabama, Mon-Thu,
- Mixed precipitation (rain, freezing rain, sleet and snow) for much of New
England, Mon, Mar 27.
- Heavy precipitation (rain and mountain snow) for the Pacific Northwest,
Mon-Tue, Mar 27-28.
- Flooding is possible, likely or imminent/occurring over parts of the
Pacific Northwest, northern and central Intermountain region, and the northern
- Heavy rain for eastern portions of both Oklahoma and Texas, and the Lower
Mississippi Valley, Sat-Sun, Apr 1-2.
- Slight chance of much above-normal temperatures from the Lower Mississippi
Valley eastward to the southern Atlantic Coast, Sat, Apr 1.
- Severe Drought across parts of Arizona, California, the central and
southern Great Plains, Arkansas, Missouri, and the eastern U.S.
At the start of the period, a cold front is predicted
to stretch southwestward from a low pressure center over the eastern Great
Lakes region to the southern Great Plains. A warm front is forecast to extend
eastward from the surface Low across the Northeast CONUS. Another low pressure
center is initially predicted on the cold front in the vicinity of the Ozark
Mountains. This complex frontal system is anticipated to bring several
weather-related hazards, the most serious of which includes multiple severe
thunderstorm outbreaks across the southern Plains, Lower Mississippi Valley,
and Lower Tennessee Valley during a three-day period. Chronologically, the
first highlighted area of severe weather is applicable for the Lower
Mississippi and Lower Tennessee Valleys on Monday, March 27th. The Storm
Prediction Center (SPC) in Oklahoma expects an axis of instability near the
southern portion of the Mississippi River, and deep-layer wind shear associated
with a belt of stronger 500-hPa flow rounding the base of the upper trough.
These conditions are thought to be sufficient for isolated areas of severe
weather. On Tuesday, March 28th, low-level Gulf moisture is anticipated to
stream northward across the southern Plains ahead of an eastward-advancing
dryline. Isolated severe weather coverage is again anticipated during the
afternoon, this time across west-central Texas and adjacent parts of Oklahoma.
The spatial coverage of severe thunderstorms is expected to increase late in
the day and evening as the 500-hPa Low and trough approach the area. Moderate
instability and strong deep-layer shear are forecast to be in place. In
addition, a well-developed low-level jet should maintain an organized severe
weather threat late Tuesday night into Wednesday, March 29th. Predicted hazards
include large hail, wind damage, and some tornadoes, as an expected squall line
organizes and moves across the southern Plains from Tuesday evening into
Wednesday afternoon. Periods of heavy rainfall are also predicted across
central and southern portions of both the Great Plains and Mississippi Valley,
extending eastward into Alabama, from March 27-30. Precipitation amounts during
this 4-day period are expected to range from 2-6 inches.
Early in this period, on March 27th, there is an increased risk of mixed
precipitation (rain, freezing rain, sleet and snow) for much of New England,
north of a predicted warm front.
Pacific storm systems are forecast to move across the West Coast states
during this period. A heavy precipitation (rain and mountain snow) hazard is
posted for the Pacific Northwest for liquid equivalent precipitation amounts of
about 2.0-3.5 inches.
Flooding is possible, likely, or occurring/imminent across parts of the
Pacific Northwest, the northern and central Intermountain region, and the
northern Rockies. This is due to unseasonably warm temperatures coupled with
rainfall during mid-March.
A significant cyclonic system may approach the Aleutians and Alaska
Peninsula from the southwest late in this period. However, substantial
disagreements between the ECMWF and GFS models regarding the forecast path of
this system preclude the specification of hazardous areas on the map at this
For Saturday April 01 - Friday April 07:
An area of heavy rain is forecast
over eastern portions of both Oklahoma and Texas, and over the Lower
Mississippi Valley, from April 1-2. This is in response to a 500-hPa trough
expected to approach this area from the west. There is also the potential for
strong to severe thunderstorms to develop once again in this general area, but
there is not enough confidence at this time to warrant the depiction of a
severe weather region.
On April 1st, there is a slight chance (20-percent) of much above-normal
temperatures from the Lower Mississippi Valley eastward to the southern
Atlantic Coast. Within this area, temperatures are expected to reach the 85th
percentile (or higher) of the historical distribution. For most areas, high
temperatures are forecast to reach the mid-upper 80's, while a few locales may
push 90 deg F.
According to the U.S. Drought Monitor released on March 23rd (using data
through 8am Eastern time, March 21st), changes compared to the previous week
included one-class degradation across parts of the southern tier of states from
New Mexico to South Carolina, parts of Oklahoma and Kansas, and Hawaii.
One-class improvements in drought category were primarily focused on the
Northeast and mid-Atlantic, Tennessee, northern Alabama, and eastern portions
of Puerto Rico. No changes to the drought depiction were made in Alaska.
Coverage of severe, or greater intensity, drought throughout the CONUS
decreased slightly from 3.95 last week to 3.74 percent this
Forecaster: Anthony Artusa
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.