Posts by Sig Silber

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Sun Mar 17 2024
Valid 12Z Sun Mar 17 2024 – 12Z Tue Mar 19 2024

…Locally heavy snow continues across the Southern Rockies today, while
lake effect snow impacts the Great Lakes region through early this week…

…Strong cold front ushers in frost/freeze potential throughout the
Southeast by Tuesday…

…Scattered showers and thunderstorms forecast across the Gulf Coast
States this St. Patrick’s Day…

Even as the Spring Equinox approaches this Tuesday, winter weather
continues to impact parts of the Nation with localized heavy snow. The
same closed upper low that has lingered over the Southwest over the last
few days is expected to continue producing areas of heavy mountain snow
throughout the Southern Rockies and Four Corners region today before the
system weakens and precipitation becomes widely scattered. The heaviest
remaining snow is expected over the mountainous terrain of New Mexico,
which could lead to treacherous travel at times. Meanwhile, a potent low
pressure system crossing from southern Ontario to southern Quebec, Canada
today will aid in lake effect snow downwind of the Great Lakes through
early this week. The cold airmass advecting from the northwest across the
relatively warm lakes will allow for numerous snow showers and localized
areas of moderate to heavy snow. Specifically, the U.P. of Michigan and
Tug Hill Plateau of western New York could see several inches of
accumulation snow. Snowfall chances also extend to upslope portions of the
central Appalachians on Monday and Tuesday.

As a cold front pushes south and clears the Southeast by Monday, much
colder temperatures and high pressure will build in its wake. Low
temperatures are forecast to dip into the 20s and 30s from the Midwest to
the Tennessee Valley on Monday, prior to this cold sinking into the
Mid-South and Southeast on Tuesday. Vegetation in these regions are
susceptible to frost/freeze damage given the relatively mild late winter
temperatures, thus any unprotected sensitive plants could be damaged or
killed. Meanwhile, warm temperatures will remain locked in place over the
Pacific Northwest, where highs into the low 70s are forecast and
anticipated to spread into the northern High Plains by Monday.

One more day of shower and thunderstorm activity is expected today along
the Gulf Coast as a lingering frontal boundary focuses rainfall chances.
Heavy rain could lead to flooding concerns from southeast Texas to
southern Louisiana due to saturated soils from recent rainfall. A Slight
Risk (level 2 of 4) of Excessive Rainfall is in effect. A few isolated
severe thunderstorms could also impact the immediate Gulf Coast region as
well this St. Patrick’s Day.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Sat Mar 16 2024
Valid 12Z Sat Mar 16 2024 – 12Z Mon Mar 18 2024

…Heavy mountain snow impacts the Four Corners and Southern Rockies this
weekend…

…Severe thunderstorms and heavy rain possible across southern Texas and
along the Gulf Coast…

…Mild weather continues across the Pacific Northwest and East Coast…

The lingering closed upper low located over the Desert Southwest is
forecast to remain mostly stationary this weekend and produce the
continued threat of heavy mountain snow from the Four Corners region to
the Southern Rockies. In particular, the high terrain of central/southern
Utah as well as the San Juan and Sangre de Cristo Mountains of Colorado
and New Mexico can expect treacherous conditions due to heavy snow.
Additional snowfall accumulations over a foot are expected for parts of
the Southern Rockies through Monday, with Winter Storm Warnings and Winter
Weather Advisories remaining in effect.

Meanwhile, a stalling cold front extending from the Southeast to southern
Texas will lead to at least a few more days of storminess for the Lone
Star State and remaining Gulf Coast region. The greatest severe weather
threat exists today across south-central Texas and the Middle Texas Coast,
where the Storm Prediction Center has highlighted a Slight Risk (level 2
of 5) for severe thunderstorms. Large hail, damaging winds, and isolated
tornadoes are possible within the strongest storms. Intense rainfall rates
falling over saturated ground may also lead to flash flooding and standing
water in urban areas throughout similar portions of Texas and stretching
into far southwest Louisiana. By Sunday, shower and thunderstorm activity
is expected to stretch along most of the Gulf Coast, with isolated to
scattered chances for severe weather and flash flooding. Given recent
rainfall, parts of southwest Louisiana and southeast Texas have been
designated as having a Slight Risk (level 2 of 4) for Excessive Rainfall.

The other notable system to impact the CONUS through early next week is
forecast to clip the Great Lakes and northern New England, producing
mostly light rain and snow showers as well as gusty winds and cooler
temperatures. Locally heavy snow is possible downwind of the Great Lakes
on Sunday and Monday. Before the chilly and below average airmass
progresses into the eastern third of the Nation on Monday, mild afternoon
temperatures into the 60s and 70s can be expected this weekend in the
East. More importantly, the cold airmass on the way will contain a morning
frost/freeze threat on Monday throughout the Midwest and Ohio Valley as
lows dip into the 20s and 30s.

Upper riding anchored over the Northwest will continue the warm and dry
pattern throughout the Pacific Northwest and northern Great Basin,
expanding into the northern High Plains on Monday. Highs into the 60s and
70s are forecast, which could break a few daily high temperature records.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Fri Mar 15 2024
Valid 12Z Fri Mar 15 2024 – 12Z Sun Mar 17 2024

…Heavy mountain snow continues throughout the Four Corners region into
this weekend…

…Severe thunderstorm and excessive rainfall chances shift south into the
Southeast and Gulf Coast States…

…Mild weather continues across the Pacific Northwest and East Coast…

A meandering closed upper low spinning over the Desert Southwest will
continue to funnel moisture northward into the Four Corners region and
create additional chances for heavy mountain snow through the weekend.
Snow chances will diminish today across the central/southern High Plains
as upslope flow weakens, but mountainous terrain of the central and
southern Rockies can expect an additional 1 to 2 feet of snow through
Sunday. The higher elevations of southern Utah and Arizona can also expect
snowfall accumulations over a foot, which will create hazardous driving
conditions. Winter Storm Warnings and Winter Weather Advisories remain in
effect for these regions.

Farther east, waves of low pressure and an associated cold front are
forecast to slide south and east today while stretching from the
Mid-Atlantic to the Southern Plains. Heavy rain and scattered
thunderstorms will accompany this system, with the greatest chances for
severe weather and/or flash flooding located across parts of the Mid-South
and south-central Texas. For these areas, thunderstorms could be strong
enough to contain damaging wind gusts and isolated tornadoes. Meanwhile,
the primary risk across south-central Texas is expected to be associated
with large hail and scattered flash flooding. By this weekend, the
aforementioned frontal boundary is forecast to stall along the Gulf Coast
and southern Texas, resulting in additional chances for heavy rain that
could lead to scattered flooding concerns from south-central Texas to
southern Mississippi.

The other notable weather system to impact the Lower 48 will be a potent
low pressure system passing to the north of the Great Lakes on Saturday
and nearing Maine on Sunday. The greatest impacts are anticipated to be
associated with gusty winds across the Great Lakes and decreasing
temperatures throughout the Upper Midwest by Sunday. Additionally, periods
of lake effect snow could be locally heavy across the U.P. of Michigan
downwind of Lake Superior. Otherwise, strong southerly flow on the eastern
side of this system will keep much of the East Coast mild with high
temperatures mainly in the 60s and 70s. The other warm spots over the next
few days include the Pacific Northwest and Southeast, where a few daily
record highs are possible. Parts of western Washington and Oregon may see
highs into the mid-70s, while mid-to-upper 80s are found throughout the
Sunshine State.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Wed Mar 13 2024
Valid 12Z Wed Mar 13 2024 – 12Z Fri Mar 15 2024

…Heavy snow develops over central Colorado Wednesday night into Thursday
followed by rain/mountain snow across the Four Corners to the southern
High Plains Thursday into Friday…

…Strong to severe thunderstorms possible from the Midwest to the
southern Plains from this evening into Thursday…

…Strong to severe thunderstorms with a slight risk of excessive rainfall
expected Thursday evening into early Friday from the southern Plains to
the Mid-South...

An amplifying upper-level trough digging into the western U.S. is
gradually pushing the unsettled weather out of the Pacific Northwest into
the Intermountain region. The interaction of the upper trough with colder
air filtering southward is setting the stage for a long-duration snow
event from the central Rockies and down into the Four Corners over the
course of the next few days. The precipitation will first be focused over
the central Rockies from this evening into Thursday when wet snow is
forecast to be the heaviest across the Front Range of Colorado where a few
feet of new snow could fall. Lesser amounts are expected in adjacent
areas but one to two feet of wet snow is possible down into the High
Plains at locations such as Boulder and Denver, Colorado. Hazardous to
very difficult travel is expected as heavy snow and intense snow rates at
times (1-2 inches plus per hour) will lead to deteriorating travel
conditions beginning Wednesday and Wednesday night across the
central/southern Rockies and beginning across the Four Corners region
Thursday night.

A second phase of the winter storm will then impact the Four Corners
Region beginning Thursday night, as the upper trough closes off into a
slow-moving upper low. Waves of heavy snow will impact the terrain areas
north of the Mogollon Rim and northeast toward the San Juans and southern
Colorado Rockies. Snow probabilities for 8 inches are moderate to high
(greater than 50%). Localized totals above a foot are possible for the
higher terrain.

On the warm side of the system, low relative humidity and gusty winds will
continue to raise the danger of wildfires to locally extreme levels from
the Texas Panhandle to western Texas today. The dry environment in the
Plains states will initially limit the formation of showers and some
thunderstorms across the mid-Mississippi Valley into the Midwest.
However, as a low pressure system develops and tracks across the central
Plains towards the Midwest, influx of moisture from the Gulf of Mexico is
forecast to organize an area of enhanced rainfall across Arkansas and
neighboring areas Thursday evening into early Friday when severe weather
is possible. The heavy rain and severe weather threat will then shift
northeast toward Tennessee by Friday morning as the trailing cold front
associated with the low pressure system approaches from the west. The low
pressure system itself will bring widespread moderate to locally heavy
rain with a slight threat of severe weather across the Midwest tonight,
followed by the southern half of the Great Lakes on Thursday, and into New
England Friday morning. The rain may mix with wet snow over the upper
Midwest tonight and over interior New England Friday morning.

As the winter storm develops over the western U.S., much of the eastern
U.S. will enter an extended period of very warm and pleasant weather.
High temperatures in the 60s and 70s from the Ohio Valley to the
Mid-Atlantic states will be 20-25 degrees above normal for this time of
year.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Tue Mar 12 2024
Valid 12Z Tue Mar 12 2024 – 12Z Thu Mar 14 2024

…One more day of unsettled weather across the Pacific Northwest and
northern California before the precipitation gradually tapers off on
Wednesday…

…Mountain snows spreading into the northern and central Rockies on
Wednesday before heavy snow develops over central Colorado Wednesday
night…

…Fire danger across the southern High Plains will be followed by chance
of severe thunderstorms across the north-central Plains later on Wednesday
as rain may change over to wet snow in the nearby High Plains…

…Anomalously warm temperatures to expand eastward from the Upper Midwest
into the Ohio Valley, Mid-Atlantic and Northeast through Wednesday…

A gradual shift in the large-scale upper-level pattern across the U.S.
will bring unsettled weather that has been impacting the Pacific Northwest
in recent days progressively eastward into the central U.S. by Wednesday
night. The final in a series of Pacific fronts and low pressure systems
will push onshore into the West Coast today, bringing additional mountain
snow and lower-elevation rain with one to possibly two feet of new snow
along the Cascades. As the main upper trough presses eastward through the
western U.S. the next couple of days, areas along the West Coast will have
a chance to gradually dry out on Wednesday. Meanwhile, the main batch of
moisture will penetrate farther inland in the form of mountain snow
pushing into the northern to central Rockies on Wednesday. The upper
trough will also help develop a low pressure system over the central High
Plains on Wednesday. The interaction of the upper trough with the
intensifying low pressure system will begin to organize and focus an area
of moderate to heavy snow over central Colorado by early on Thursday. By
Thursday morning, snow could be falling in earnest over the mountainous
terrain into the Front Range and nearby High Plains of central Colorado.

On the warm side of the low pressure system, low relative humidity and
gusty winds will continue to raise the danger of wildfires across central
to southern High Plains today, followed by a more southward focus from the
Texas Panhandle to western Texas on Wednesday. The dry environment in the
Plains states will initially limit the formation of showers and some
thunderstorms across the mid-Mississippi Valley into the Midwest today
into early on Wednesday. However, as the low intensifies, influx of
moisture from the Gulf of Mexico is forecast to organize an area of
enhanced rainfall over the vicinity of Nebraska Wednesday night as the
storm center passes just to the southeast. Some of the enhanced rainfall
could be accompanied with severe weather. In addition, there is a
possibility that the western portion of the enhanced rainfall would change
over to wet snow early on Thursday if additional cold air wraps around the
storm center.

Across the eastern U.S., the departure of a strong surface low near Nova
Scotia into the western Atlantic will allow the gusty winds to moderate
further across the northern Mid-Atlantic and Northeast today. Breezy
conditions are likely to remain for northern New England into Tuesday
night, but overall improvement is expected. High pressure over the
southern U.S. will slide eastward over the next couple of days, allowing
winds to return from the south, bringing warmer temperatures northward.
The greatest departures from normal highs will remain over the Upper
Midwest and Great Lakes region on Tuesday which may cause a few record
daily maximum temperatures to be broken, but the magnitude of the
anomalous warmth is likely to be lower on today compared to Monday. High
temperatures in the 60s to lower 70s will expand eastward through
Wednesday across the Ohio Valley and portions of the northern Mid-Atlantic
into the Northeast, roughly 15 to 25 degrees above mid-March averages.
With the warmer weather will come the threat for thunderstorms across
portions of the central U.S. Some severe thunderstorms will be possible
ahead of a dryline from eastern Oklahoma/Kansas into western Missouri on
Tuesday with a broader risk across some of these same areas on Wednesday.
Again, the prevailing dry environment will initially limit the intensity
of the storms.