Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/01/22
Area Forecast Discussion
National Weather Service Charleston SC
1033 PM EST Mon Feb 28 2022
.SYNOPSIS...
High pressure will build into the region tonight and remain the
dominant feature for most of this week. Late this week, a large
low pressure system will organize over the Central Plains,
lifting a warm front north of the region this weekend into
early next week.
&&
.NEAR TERM /THROUGH TUESDAY/...
The trough in the mid levels is offshore and heading due east,
taking with it much of the deep moisture. The Charleston
sounding from 00Z has PWat down to 0.44 inches, which is 0.75
inches less than last night at the same time.
The HRRR has been showing a small chance of a few showers
redeveloping near or onshore overnight. But this scenario seems
unlikely given minimal moisture and convergence, plus
isentropic downglide. Instead there will be some stratocumulus
that develop and/or advect onshore, with thin cirrus that
arrives with the sub tropical jet overnight.
Recent satellite trends have shown more clearing than originally
expected, and thus some places will get a bit colder. In fact
there could be a little frost in northern berkeley County, where
a few places could dip into the mid 30s.
Previous discussion...
The mid level trough will pull offshore this evening and then
further out to sea thereafter. This allows for surface low
pressure off the coast of Daytona Beach and Cape Canaveral to
deepen a bit as it shifts further out into the ocean through the
night. Wrap around moisture from the feature will also decrease
locally, and as PVA weakens and gives way to NVA and coastal
convergence slackens, the risk for any showers looks to stay
over the Atlantic through the night.
There will be an increase in cloud cover over coastal sections due
to stratocumulus advecting onshore within a low level east to
northeast flow, and then from some late night cirrus in
response in a weak and elongated short wave. On average skies
will be mostly clear or partly cloudy well inland and partly to
mostly cloudy closer to shore.
Due to large dew point depressions and winds slackening off
inland, we look to get enough cooling to drop lows near or even
a tad below climo. Coldest spots will be over the northwest
counties, with the warmest along the barrier islands where
mixing persist through the night.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
Tuesday: Sfc high pressure centered over the lower Mississippi River
Valley will build east across the region through the day. The
forecast area will remain under a broad trough aloft, with the
trough axis over the western Atlantic. The dry NW flow aloft will
result in decreasing cloud cover through the day. Temperatures are
expected to peak in the low 70s across SE GA to the upper 60s across
the CHS Tri-county.
Wednesday: Warm and dry conditions expected. Mid-level zonal heights
and ridging sfc high pressure will remain across the forecast area.
High temperatures are expected to range in the mid to upper 70s. The
mild temperatures should result in mixing heights are forecast to
deepen to 4 kft or more. As a result, sfc dewpoints should lower
into the low to mid 30s, with RH values across inland GA and SC
falling into the low to mid 20s.
Thursday: A dry backdoor cold front will approach the CWA from the
north during the daylight hours. With the front remaining just north
of the forecast area, high temperatures should easily reach around
80 degrees.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Long term guidance indicates that the backdoor cold front will push
over the forecast area late Thursday night into Friday morning,
contributing very little cloud cover.
An area of low pressure will organize and deepen over the Central
Plains late this week, tracking to the NW over the Mid West this
weekend. The backdoor cold front over the region on Friday, will
lift north as a warm front later this week. A cold front associated
with the Mid West low is expected to sweep across the Mississippi
River by Monday. This pattern should provide the region with gradual
WAA this weekend into early next week. High temperatures should warm
each day, reaching the mid to upper 80s on Monday.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
VFR looks to prevail with the 00Z TAF set at KCHS, KJZI and
KSAV. However, we will need to carefully watch for a period of
marginal MVFR ceilings overnight into Tuesday morning due to a
persistent onshore flow.
Extended Aviation Outlook: VFR.
&&
.MARINE...
Overnight: About a 2-3 millibar spread will exist across the
local waters between high pressure to the north and low pressure
off the Florida coast. This will support NE winds as high as
20-25 kt and gusty over the ocean, and thus a continuation of
the Small Craft Advisories. Charleston Harbor will have a bit
more slack gradient, but still enough for NE winds up to 15 kt.
A favorable fetch will allow for elevated seas to persist,
still as high as 4-6 feet within 20 nm and up to 7 or 8 feet on
the over Georgia waters.
Tuesday through Saturday: Small Craft Advisory conditions will
persist through Tuesday morning across all waters outside the
Charleston Harbor, with 6ft seas and wind gusts in the low 20 knots
to around 25 knots. Conditions will likely improve within the
nearshore waters Tuesday afternoon, with conditions across the
offshore GA waters improving by daybreak Wednesday morning. Quiet
marine conditions are expected thereafter as high pressure builds in
at the surface.
&&
.TIDES/COASTAL FLOODING...
The combination of astronomical forces and gusty northeast winds
will result in a continuation of elevated tides overnight and
Tuesday. Looking at anamolies the past four high tides,
departures have been around 0.8 to 1.0 ft MLLW above predicted.
If this trend were to continue it would produce minor coastal
flooding with the 7 AM high tide in Charleston and coastal
Colleton. If winds don`t back too much northerly with land
breeze influences, tide levels might even be higher.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory until 1 PM EST Tuesday for AMZ350-352-354.
Small Craft Advisory until 7 AM EST Wednesday for AMZ374.
&&
$$
NEAR TERM...
SHORT TERM...NED
LONG TERM...NED
AVIATION...
MARINE...
TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service North Platte NE
551 PM CST Mon Feb 28 2022
.SHORT TERM...(This evening through Tuesday night)
Issued at 336 PM CST Mon Feb 28 2022
Northwest flow aloft continues tonight through Tuesday night and the
extensive area of mid and high clouds across the northwest U.S.
shown on satellite will remain mostly north of wrn and ncntl Nebraska
during this time. A weak sfc trof of low pressure will move
through the region tonight. This will cause an increase in
moisture with precipitable water increasing to 0.40 inches by
morning. The atmosphere should remain mixed and the RAP model
shows h850mb winds increasing to 30 to 45 kts-from the northwest.
These winds will decrease during the day Tuesday but moisture
will continue to increase with precipitable rising to near 0.50
inches by late afternoon.
The temperature forecast tonight and Tuesday uses a blend of the
guidance and the 50th percentile of the NBM for lows in the mid 20s
to lower 30s and highs in the mid 60s to lower 70s. Temperatures
continue to warm aloft Tuesday night and precipitable water remains
nearly static at 0.50 inches. This would seem to support warmer lows
in the upper 20s to mid 30s as suggested by the short term model
blend.
.LONG TERM...(Wednesday through Monday)
Issued at 336 PM CST Mon Feb 28 2022
Back to back storms will cross the cntl Plains Friday night-
Saturday and then Sunday-Sunday night. The GFS will track both
systems through nwrn Nebraska and then through SD while the ECM
tracks both systems through the heart of wrn and ncntl Nebraska. The
ensembles are generally similar with the track with minor north and
south differences.
There is little change in the temperature forecast Wednesday. A
slight mark up is in place using the guidance blend and the 50th
percentile of the NBM. This suggested highs in the upper 60s to mid
70s.
A back-door cold front will drop through wrn and ncntl Nebraska
Wednesday night. The models are a little faster with the front and
this could affect the temperature forecast Wednesday across ncntl
Nebraska. The models are also trying to erode the cold air in place
Friday. This seems fishy given it is modified arctic air. Highs in
the 50s and 60s are in place across wrn and ncntl Nebraska Friday.
A check on the ECM thunderstorm forecast Friday indicates the
better chances will be across nrn KS and areas generally south of
Interstate 80 in Nebraska. These storms, if the form, will likely
focus on the sfc cold front which will be across KS.
Otherwise, the rain-snow forecast continues pretty much on track.
The models are slowing the onset of the precipitation down slightly
but the best chance continues to be Friday night and Saturday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 548 PM CST Mon Feb 28 2022
VFR conditions will prevail through the next 24 hours. There will
be some LLWS that moves in overnight, with gust of 35 kts, generally
closer to midnight and before sunrise. Surface winds will remain
light through the evening and overnight out of the west to west
northwest, with wind speed under 10 kts. Tomorrow afternoon winds
will become breezy across the northern Sandhills into north
central Nebraska with some locations seeing gust up to 25 kts.
Winds will remain out of the west northwest tomorrow afternoon.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...CDC
LONG TERM...CDC
AVIATION...Gomez
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