ATTENTION: For more information on the addition of the experimental Rapid Onset Drought hazard type to the Climate Prediction Center's 8-14 Day Hazards Outlook (Contiguous U.S. and Alaska), please click HERE.
Valid Friday April 05, 2024 to Thursday April 11, 2024
US Hazards Outlook NWS Climate Prediction Center College Park MD 300 PM
EDT March 28 2024
Synopsis: An area of departing surface low
pressure across the northeastern contiguous U.S. (CONUS) may bring periods of
high winds to portions of the Northeast at the start of the week-2 period.
Meanwhile, a digging trough and associated lee-side cyclogenesis will bring
multiple chances for heavy snow to parts of the northern and central Plains and
Rocky Mountains. More broadly, periods of high winds may occur in conjunction
with the robust trough and a series of surface lows across the West. In the
Southeast, return flow off the Gulf of Mexico and frontal systems extending
from multiple areas of low-pressure across the Plains brings chances for heavy
precipitation to portions of the southeastern CONUS by the middle and end of
the period.
Hazards
Slight risk of high winds for parts
of the Northeast, Fri, Apr 5.
Slight risk of heavy snow for portions of the Northern and Central Plains
and the Central and Southern Rocky Mountains, Fri-Tue, Apr 5-9.
Slight risk of episodic high winds for the Great Plains and Interior West,
Fri-Tue, Apr 5-9.
Slight risk of heavy precipitation for portions of the Middle and
Lower-Mississippi, Tennessee, and Ohio River Valleys, Southern Plains, and
Southeast, Sun-Thu, Apr 7-11.
For Friday April 05 - Thursday
April 11: Mid-level troughing and associated surface low-pressure will be
progressing east off of the Northeast at the end of week-1. Models are in fair
agreement with this system bringing chances for high winds to portions of the
Northeast at the very beginning of week-2. The GEFS and ECENS have many members
forecasting the mean sea level pressure (MSLP) to fall towards 990mb.
Therefore, a slight risk of high winds is posted for Apr 5. However, much of
this system is forecast to be east of the US by the start of week-2 and the
associated snow hazard forecast yesterday has been discontinued.
Across the interior West, an area of negative mid-level height anomalies is
forecast to develop and persist for much of the week-2 period. This is likely
to bring generally unsettled weather to much of the western and central
contiguous U.S. (CONUS) during the period. As the trough digs into the West
early in the period, the ECENS Probabilistic Extremes Tool (PET) shows at least
a 20% chance of wind speeds exceeding the 85th percentile and 20 mph (25 mph,
locally) across the highlighted risk area. The GEFS PET indicates these
thresholds for the Southwest into the Central Plains. Lee-side cyclogenesis is
also likely to support increased chances for high winds further into the
Central and Northern Plains during much of the period. Finally, the National
Interagency Fire Center (NIFC) indicates low to moderate fire potential across
parts of the eastern Four Corners region and Central and Southern Plains by the
end of week-1. Little to no precipitation anticipated during week-1 combined
with increased high wind risk during week-2 may support enhanced wildfire risk
in these regions. Therefore, a slight risk of episodic high winds is posted for
the Great Plains, Interior West, and Southwest, Apr 5-9. By the end of the
period the mid-level trough is likely to be moving east and weakly above-normal
500-hPa heights are forecast reducing the chances for high winds across the
region.
The digging mid-level trough and cyclogenesis in the lee of the Rockies
increases chances for heavy snow across portions of the Plains and Rockies. The
GEFS Snow Water Equivalent (SWE) PET indicates chances for SWE to exceed the
85th climatological percentile across portions of the Plains. Meanwhile, the
ECENS PET indicates precipitation to exceed the 85th percentile across a broad
area in the north-central CONUS. Correspondingly, the raw ECENS indicates
30-40% chances for snow to exceed four inches across this region during the
early to middle of the period. Therefore, a slight risk of heavy snow is posted
for the Central Rockies and Northern and Central Plains for April 5-9.
Return flow off the Gulf of Mexico may develop by the middle through the
end of week-2. The associated frontal systems from the lee cyclogenesis
discussed above may help to initiate chances for heavy precipitation in parts
of the southeastern CONUS. The ECENS and GEFS PETs develop over 20% chances for
3 day precipitation amounts to exceed the 85th percentile and 1 inch across a
wide area in the southeastern CONUS. There is also broad support from the raw
tools as well for this region with 3 day precipitation amounts from the raw
ECENS indicating greater than a 40% chance of exceeding 1 inch. Therefore, a
slight risk of heavy precipitation is posted for this region for Apr 7-11.
For Alaska, the mean mid-level pattern is forecast to be fairly zonal, with
potentially positive 500 hPa height departures across the southern half of the
state. There is multi-model depiction of a series of surface lows forming over
the Bering Sea and Gulf of Alaska, although these are not expected to lead to
widespread hazardous conditions.
Forecaster: Ryan Bolt
$$
Please consult local NWS Forecast Offices for short range forecasts and region-specific information.