Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/10/25
Area Forecast Discussion
National Weather Service La Crosse WI
930 PM CST Sun Feb 9 2025
.KEY MESSAGES...
- Light snow on Monday evening and into the overnight with accumulations
under 1 inch. Highest chances (50-70%) for snow across
northeast IA and southwest WI.
- Colder temperatures for this week with morning wind chills
falling as low as 25 degrees below zero in southeast MN and
north-central WI on Tuesday morning. High temperatures on
Tuesday through Thursday will be in the single digits and
teens areawide.
- Additional snow potential for Wednesday with the highest
chances for measurable snow (60-80% chance) across southwest
WI and northeast IA.
&&
.DISCUSSION...
Issued at 238 PM CST Sun Feb 9 2025
Rest of Today - Monday Night: Slightly Cooler Than Normal, Light
Snow Later on Monday
GOES-16 water vapor imagery and 09.12z RAP 500mb heights show our
region subjected to a zonal to northwesterly flow pattern right now
with some enforcement of colder air with 850mb temperatures in the
09.12z RAP around -12C to -15C across the region. Current
observed temperatures conform to where the snowpack is quite
nicely with temperatures already in the 20s in Platteville and
Boscobel but colder farther north with temperatures stuck in the
teens at La Crosse and Rochester. Consequently, have nudged
temperatures down throughout much of the next few days colder
than the national blend as its bias correction likely fails to
account for the recent snowpack and overall pattern change.
As we head later into Monday evening, a shortwave trough will push
north of the area subjecting our region to northwesterly flow and
cold air advection with a passing cold front. As this occurs on
Monday evening, low-level frontogenesis develops across the area
which the CAMs instigate an area of light snow west of the
Mississippi River. Quite a large degree of difference between the
CAMs but generally agree on light snow moving into northeast IA and
southeast MN by the evening hours with pushing southeast into
southwest WI into the overnight. Overall, given the lack of steeper
low-level lapse rates and extremely low probabilities (0-10% chance)
for anything greater than 0.1" of QPF in the 09.12z HREF,
accumulations will likely be minimal. Probabilities for an inch or
greater of snow accumulation assuming a 20:1 SLR in the 09.12z HREF
are medium (30-50%) across northeast IA but very low (0-20%)
elsewhere. As we enter the early morning hours on Tuesday, this
frontogenesis begins to weaken and the associated precipitation band
in the CAMs weakens as it exits the local area.
Tuesday - Thursday: Colder, Mid-Week Snow Potential
Temperatures throughout the middle of the week will trend below
normal with daytime highs in the single digits and teens through
Thursday. As the aforementioned cold front passes through the area
into early Tuesday morning and 850mb fall to -18C to -22C shown in
the 09.15z RAP/NAM, morning lows will plummet below zero for most of
the local area aside from southwest WI. With the more robust
snowpack in north-central WI, these areas will likely fall into the
negative double digits with even an isolated spot or two hitting 20
degrees below zero by Wednesday morning in Taylor County. Wind
chills on Tuesday morning may fall as low as 25 degrees below zero
in portions of north-central WI and southeast MN. However, with high
pressure building in Tuesday afternoon and into early Wednesday
morning, winds should calm enough that your air temperature will be
what you feel outside on Wednesday morning.
As for precipitation chances, the continued trend has been a more
robust synoptic upper-level trough to swing out of South-Central
Canada and into the Upper Midwest. This a accompanied with a more
subtle shortwave trough that pushes through NE/KS and into the Ohio
Valley with a developing surface low as shown in the 09.12z EC/GFS.
The remaining question will be exactly how these two systems will
interact but the continued consensus is that portions of our region
will be subjected to the resulting deformation zone but questions on
what the northwestern extent will be. Currently, the 09.00z grand
ensemble (GEFS/EC/Canadian ensemble) has high probabilities (60-90%)
for measurable snow but medium probabilities (30-60%) for greater
than 1 inch of snow in portions of southwestern WI and lowering
probabilities as you head northwest. Consequently, have opted to
hold onto the high precipitation chances (60-80%) from the national
blend for now. As far as precipitation type is concerned, GFS
soundings during this period across the area show healthy residency
in the dendritic growth zone so would expect an entirely snow
solution at this time with the probabilistic p-types in the NBM
confirming this notion.
Friday - Saturday: More Seasonable with Additional Snow Chances
Looking towards Friday, upper-level ridging builds in behind the
aforementioned trough so temperatures respond accordingly with highs
becoming slightly more seasonable in the 20s for Friday and
Saturday. As far as precipitation chances are concerned
deterministic guidance shows two upper-level troughs yet again, one
descending out of the Canadian plains and into the Upper Midwest and
secondary one that swings through the Ozarks on Saturday. Overall,
predictability at this stage remains on the low end. However, the
09.00z grand ensemble (GEFS/EC/Canadian ensemble) keeps fairly high
(60-80%) probabilities for measurable snow with that upstream
system and little indication in the current state of the upper-
level flow pattern that the southern stream trough will be able
to impact the region at this time as shown in deterministic
guidance (09.12z GFS/EC).
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 930 PM CST Sun Feb 9 2025
CIGS: generally skc through the night, then increasing upper/mid
level clouds Mon morning with a gradual lowering in the afternoon.
HREF suggests a few hour drop into MVFR for both KRST and KLSE (60-
80% sub 3 kft) around 00z, lingering into the mid evening hours
Monday. Some mixed message though with the HRRR and a few others
holding the lower cigs south. Will keep mention at KRST but hold off
at KLSE for now.
WX/VSBY: some threat for -SN from a bit of upper level energy and
mid level Fgen late Mon afternoon/evening. There are mixed signals
in the short term guidance, although most favor bringing the
northern extent of any light snow to I-90. With chances generally
around 30% opting to not add to the forecast yet. If it would
manifest only minimal impacts with little if any accums and perhaps
no reductions to vsbys.
WINDS: variable to light southwest this evening gradually becoming
northwest later tonight/early Mon morning. Speeds generally under 10
kts through the period.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...Naylor
AVIATION.....Rieck
Area Forecast Discussion
National Weather Service Charleston SC
1004 PM EST Sun Feb 9 2025
.SYNOPSIS...
A cold front will approach from the north tonight, then pushes
through the area Monday, High pressure will then build in from
the north behind the front into Tuesday. A warm front will
develop nearby on Wednesday, then lift north, followed by a
stronger cold front late in the week. Another cold front could
impact the area Sunday.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Late this evening, KCLX detected isolated showers moving east
across the Fall Line of SC. These showers should continue to
develop along and ahead of an approaching cold front. Recent
runs of the HRRR indicates that coverage of the showers may
increase to scattered for portions of the SC Lowcountry. Behind
the front, low stratus should spread across SE GA and SC. Low
temperatures are forecast to range from the low 50s across the
CHS Tri-county to around 60 across SE GA.
Another round of fog/low stratus should approach from the Gulf
of Mexico late tonight. The leading edge could push into the
southern Georgia counties by daybreak Monday. A Dense Fog
Advisory could be needed.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
Monday: It`s certainly a challenging forecast regarding
temperatures, as a backdoor cold front that is near the I-26
corridor at daybreak, slides south through the day. The front will
get a push from high pressure building in from the north, causing
the front to cross the Savannah River by midday, before it clears
the Altamaha River during the afternoon. Cold advection will develop
in wake of the front, causing temperatures to climb very little,
before leveling off or even falling through the afternoon. This
occurs with considerable low clouds that advect in behind the front,
which reminds us here is South Carolina that it`s still winter. Not
so just yet in Georgia, as places to the south of I-16 will be the
warmest, as it reaches the lower and middle 70s. There isn`t much in
the way of forcing, but with just enough low level convergence near
the front, maybe a few showers can develop.
Monday night: The inland wedge, and it`s associated Cold Air Damming
(DAM) is firmly in place. Cold advection is even more pronounced,
and will drop temperatures down into the 40s, with even some upper
30s possible in parts of Berkeley County. Maybe a few showers near
the coast with weak low level convergence and some isentropic ascent
developing.
Tuesday and Tuesday night: The wedge remains anchored inland during
most if not all of the day, but does begin to erode at night.
Isentropic ascent and plenty of moisture will generate isolated to
scattered showers at times through the period. Rainfall amounts look
very light however. There is a large range in temperatures once
again on Tuesday, ranging from the mid and upper 50s far north to 70-
72F far south. Adjustments will likely be required in later
forecasts. Lows Tuesday night won`t be as cold as the previous
night, as the wedge begins to break down and a warm front begins to
form nearby.
Wednesday: The warm front that is over or near the area early on,
will begin to move north, as low pressure lifts northeast from the
lower Mississippi Valley and pulls the front slowly north. Guidance
provides mixed signals on how far north the front does get through
the day, so a huge bust in temperatures is possible. The most recent
forecast shows near 70 far north, and 80-82F south, but refinements
will be required as the week progresses, and the location of the
front becomes better defined. isolated to scattered PoPs are
forecast, with the highest chances north and northwest where the
deepest moisture coincides with the proximity to a 30-40 kt 850 mb
jet.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
A stronger cold front is expected to approach on Thursday, moving
offshore Friday as high pressure begins to build in from the north
into Saturday, with another cold front Sunday. There are dynamics
that occur with both cold fronts, and even some modest MLCAPE,
suggesting that t-storms are possible. Any risk for severe weather
is very low at this time. There is also the potential for beneficial
rains with both cold fronts. Thursday and Sunday will be the warmest
days, with the coldest nights Thursday and Friday night.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
Prior to the 0Z TAFs, IR satellite and surface observations
indicated a wavy cold front just north of the SC/NC state line
bending south across the midlands of SC. The cold front will
approach the terminals late tonight. Isolated to scattered
showers may develop ahead of the front, passing near KCHS and
KJZI after 5Z, highlighted with VCSH. In the wake of the front,
high pressure should surge across the terminals Monday morning.
By 12Z, winds should turn from the northeast and increase to 10
kts or more with IFR to MVFR ceilings. At KSAV, northeast winds
may start to gust between 15 to 20 kts at 15Z.
Extended Aviation Outlook: Prevailing flight restrictions in low
clouds will occur early this week, then more temporarily in
showers and maybe a few TSRA during mid and late week. There is
also the risk for sea to advect onshore in advance of the cold
front for Wednesday night and Thursday.
&&
.MARINE...
Tonight: A backdoor cold front will approach tonight from the
northwest, pushing into the Charleston County waters by daybreak.
Southwest winds will briefly diminish this evening to 10-15 kt
before a surge of northeast flow moves in from the north late
tonight/early Monday. Seas will range 2-3 ft on average, building to
4 feet in the Charleston County waters early Monday.
Marine Fog: An area of fog/low stratus should once again approach
from the Gulf of Mexico late tonight. The leading edge could
push into the southern Georgia waters before daybreak Monday. A
Marine Dense Fog Advisory could be needed.
Monday and Monday night: A backdoor cold front that is across the
Charleston County waters at daybreak Monday will push south through
the day, reaching near the Savannah River during midday, then
clearing the Georgia waters during the afternoon. A strong wedge of
high pressure develops behind the front, and the resulting pinching
of the gradient and cold advection will result in increasing NE
winds and building seas. As a result we have raised a Small Craft
Advisory for the South Carolina waters, starting at 15Z off
Charleston County, and 18Z off the rest of the South Carolina waters.
Advisories will likely be required further south off the Georgia
coast, but since it looks to hold off until very late Monday or even
Monday night, we held off on its issuance at this time. We`ll need
to monitor for some fog on the Georgia waters south of the front,
as well as low clouds in wake of the front, which might cause some
reductions in visibility.
Tuesday through Friday: The inland wedge on Tuesday erodes Wednesday
as a warm front lifts through the area. A strong cold front
approaches later Thursday into Thursday night, with continental high
pressure to build Friday. Some lingering 6 foot seas Tuesday
suggests that we might still have a Small Craft Advisory on the
outer Georgia waters, with the next chance for any Small Craft
Advisories to occur behind the cold front late in the week. In
addition, sea fog is possible within a warm S-SW flow atop the
cooler shelf waters Wednesday into Thursday. Plus there could be
some stronger t-storms ahead of the cold front Thursday and/or
Thursday night.
&&
.CLIMATE...
Record High Temperatures:
February 9:
KCHS: 84/2025*** (previous 80/1949)
KCXM: 81/2025*** (previous 76/1921)
KSAV: 83/1957
February 13:
KCHS: 78/1976
Record High Minimum Temperatures:
February 13:
KCXM: 62/2020
KSAV: 64/1880
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory from 10 AM Monday to 10 AM EST Tuesday
for AMZ350.
Small Craft Advisory from 1 PM Monday to 7 AM EST Tuesday for
AMZ352.
&&
$$
NEAR TERM...NED
SHORT TERM...
LONG TERM...
AVIATION...NED
MARINE...
Area Forecast Discussion
National Weather Service Cleveland OH
922 PM EST Sun Feb 9 2025
.SYNOPSIS...
High pressure will build east across the region tonight into
Monday before exiting to the east Monday night. A cold front is
expected to cross the local area Tuesday with a low pressure
system moving across the region Wednesday night into Thursday.
High pressure is expected to build back in on Friday.
&&
.NEAR TERM /THROUGH MONDAY NIGHT/...
905 PM Update...
Made some minor temperature adjustments overnight. but overall,
the main theme of the forecast has not changed. Keeping the POPs
in over the northeastern zones. High pressure building into the
southern Great Lakes Monday.
Previous Discussion...
Overcast skies continue to persist across the region as shown by
surface observations and satellite imagery. A weak shortwave
currently over lower Michigan is expected to move eastward
across Lake Erie and southern Ontario this evening into tonight,
bringing isolated to scattered snow showers to parts of
Northeast Ohio and Northwest Pennsylvania. Latest afternoon
cycles of the HRRR and NAM Nest even suggest a real quick burst
of moderate snowfall could be possible between 00-06Z with a
quick inch or so of snow accumulation possible in Northwest
Pennsylvania. Because of this, increased PoPs and sky cover so
that there is a greater sized area of PoPs > 20% and peak PoPs
of 40% (although if this trend continues this will need to be
further increased) with broken/overcast skies holding on for
longer tonight. Chilly temperatures are expected tonight with
lows in the teens. High pressure builds in on Monday and Monday
night, should see clouds clear out with a decent amount of
sunshine areawide by Monday afternoon before clouds build back
in from the southwest Monday night.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
W`erly flow aloft is expected Tuesday through Tuesday night. A
subtle shortwave trough embedded in the flow aloft traverses our
region on Tuesday and allows a weak cold front to sweep SE`ward
through northern OH and NW PA. Behind the front, a ridge at the
surface and aloft builds from the Upper Midwest through Tuesday
night. Primarily fair weather is expected. However, low-level
convergence/ascent along the front should combine with limited low-
level moisture to trigger isolated snow showers, especially roughly
along and east of I-71 in our CWA. Where snow occurs, any snow
accumulations are expected to be a trace. Daytime highs are expected
to reach the mid 20`s to lower 30`s in NW PA and the upper 20`s to
mid 30`s in northern OH, ahead of the cold front. Net low-level CAA
behind the front will contribute to overnight lows reaching the
teens in NW PA and the mid teens to lower 20`s in northern OH around
daybreak Wednesday.
The ridge at the surface and aloft exits E`ward on Wednesday through
Wednesday night as a trough aloft approaches from the Intermountain
West and Great Plains. At the surface, the attendant trough
overspreads our CWA from the south and west as a deepening low
tracks NE`ward along the aforementioned front from the south-central
United States toward the eastern Great Lakes region. The cold front
trailing the low should sweep SE`ward across most of our CWA
Wednesday night and near a roughly Erie to Youngstown line by
daybreak Thursday morning. NWP models have come into better
agreement regarding the track of this low during the past 24-hours
or so. Afternoon highs on Wednesday should reach the upper 20`s to
lower 30`s in NW OH and the lower to mid 30`s elsewhere. Lows should
reach the mid to upper 20`s in essentially the eastern-half of our
CWA Wednesday evening before temperatures moderate by a few degrees
after midnight, prior to the cold front passage, as net low-level
WAA strengthens ahead of the deepening surface low. Elsewhere in our
CWA, lows should reach the lower to mid 20`s around daybreak
Thursday morning given the projected path of the low and expected
timing of the trailing cold front`s passage.
Isentropic ascent associated with the low`s warm conveyor belt will
tap into abundant moisture from the Gulf and allow precip, probably
steady to heavy at times, to overspread our region generally from
the south Wednesday afternoon through evening and then persist
through the overnight hours. This precip is expected to fall as
primarily snow in far-NW OH, including Lucas County, while a mix of
snow/sleet/freezing rain is expected elsewhere as an elevated
melting layer overspreads wet-bulb temperatures of 32F or colder
at/near the surface. However, this mix of wintry precip should
change to plain rain for a time from roughly Knox County to Mahoning
County and then to Crawford County, PA as net low-level WAA
increasing with height may allow the elevated melting layer to
deepen considerably and become surface-based. Precip types and
amounts remain contingent on the exact track of the low at/near the
surface.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
The aforementioned trough aloft should traverse our region from west
to east on Thursday and then exit E`ward Thursday night as a ridge
builds from the northern and central Great Plains and vicinity. At
the surface, the low should track NE`ward from the eastern Great
Lakes to near Newfoundland and be followed by the ridge building
from the northern and central Great Plains. Widespread precip should
end from west to east Thursday morning as the low pressure system`s
warm conveyor belt exits generally E`ward. Any plain rain or mixed
precip is expected to change quickly to snow before precip ends as
net CAA at the surface and aloft follows the low`s trailing cold
front, which should exit the rest of our CWA to the southeast by
late morning. Storm-total snowfall of a coating to several inches is
possible and the gradient in totals should be directed toward the
northwest. Storm-total ice accumulations of a trace to 0.20" are
possible. Stay tuned for forecast updates regarding this next
synoptic winter storm system, including potential issuance of winter
WX alerts.
Behind the cold front, WNW`erly mean low-level flow may be
sufficiently-cold/moist to allow isolated and light LES showers to
impact the primary snowbelt and vicinity Thursday afternoon and
evening before significant low-level dry air advection causes weak
lake-induced CAPE over cracks in lake ice cover to wane. Little or
snow LES accumulation is expected. Otherwise fair weather is
expected through Thursday night. Daytime highs should reach the mid
to upper 30`s in far-eastern portions of our CWA Thursday morning,
prior to the cold front passage. Highs are expected to reach the
upper 20`s to lower 30`s elsewhere. Lows should reach the upper
single digits to mid teens around daybreak Friday morning as partial
clearing, slight easing of surface winds, and nocturnal cooling
occur amidst a continued net CAA regime.
The ridge at the surface and aloft continues to build E`ward on
Friday. Stabilizing subsidence accompanying this ridge will likely
permit fair weather. Daytime highs should reach the 20`s to lower
30`s as a cold air mass lingers. The ridge at the surface and aloft
should exit E`ward Friday night through this weekend as the next
trough at the surface and aloft overspreads our region from the
Intermountain West and Great Plains. The attendant surface low may
develop and wobble ENE`ward from the southern Great Plains to the OH
Valley and then toward southern New England. Periods of precip,
mainly in the form of snow, should impact our region Friday night
through this upcoming weekend as the low pressure system`s warm
conveyor belt taps into abundant moisture originating over the Gulf
and undergoes isentropic ascent. However, low-level WAA increasing
with height will probably cause snow at precip onset to change to
mixed wintry precip and then to plain rain where an initially
elevated melting layer manages to become surface-based on Saturday.
However, during Saturday night and Sunday, any mixed precip or plain
rain should change back to snow as net CAA at the surface and aloft
occurs along the backside of the aforementioned surface low. We will
continue to monitor this potentially-impactful synoptic winter storm
system. Afternoon highs should reach the 30`s to lower 40`s on
Saturday. Overnight lows should reach the 20`s Saturday night.
Sunday should have highs reach the mid 20`s to lower 30`s in the
afternoon.
&&
.AVIATION /00Z Monday THROUGH Friday/...
High pressure building into the region.
MVFR ceilings persist through much of the overnight period.
light SHSN for YNG/ERI possible in the first 6 hours of the TAF,
and could see brief IFR visibilities at ERI in precipitation.
MVFR ceilings scatter out towards morning, then VFR through the
remainder of the forecast period/00Z Tuesday. Winds less than
10kts, generally out of the west or northwest.
Outlook...Non-VFR may return with light snow across the
southern half of the area on Tuesday. IFR and lower conditions
are expected areawide Wednesday afternoon through Thursday with
mixed precipitation, including snow, sleet, freezing rain, and
rain.
&&
.MARINE...
A ridge builds from the Upper Midwest through Monday before exiting
E`ward from Lake Erie Monday night. Primarily SW`erly to W`erly
winds around 5 to 15 knots through Monday are expected to back to
primarily S`erly and ease to around 5 to 10 knots Monday night. A
weak cold front is still expected to sweep SE`ward across Lake Erie
on Tuesday and will cause mainly S`erly winds around 5 to 10 knots
to veer to NW`erly or NE`erly. Behind the front, a ridge builds from
the north-central United States through Wednesday, which will allow
winds to become NE`erly over the entire lake and freshen to around
10 to 20 knots. The ridge is expected to exit E`ward Wednesday night
through Thursday as a strengthening low moves NE`ward from near the
Lower OH Valley toward southern Quebec. This will allow NE`erly
winds around 10 to 20 knots to back gradually to W`erly. Another
ridge is expected to impact Lake Erie Thursday night through Friday
as the parent high pressure center moves from near the Mid MS Valley
toward the Northeast United States. Accordingly, winds around 5 to
15 knots should back gradually from W`erly toward S`erly.
Most of Lake Erie remains ice covered and waves will be limited in
any ice-free areas. Small Craft Advisory issuance remains suspended
until further notice due to extensive ice cover.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.
&&
$$
SYNOPSIS...Saunders
NEAR TERM...26/Saunders
SHORT TERM...Jaszka
LONG TERM...Jaszka
AVIATION...26
MARINE...Jaszka
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
610 PM CST Sun Feb 9 2025
...New AVIATION...
.SHORT TERM...
(Tonight through Monday night)
Issued at 222 PM CST Sun Feb 9 2025
Key Messages:
- Cold front to gradually move southward this evening.
- Cloudy and cool on Monday with fog and drizzle in the morning.
As of early this afternoon, a slow-moving cold front is currently
located from just east of Del Rio to near Castroville to
Hallettsville. Clouds and cold air advection behind the front are
keeping temperatures as low as the upper 40s over northern Val Verde
county, with mainly lower 50s to mid 60s farther east into the Hill
Country and I-35 corridor. Ahead of the front, temperatures are
still in the 70s and should continue to nudge upward given the
recent breaks in the cloud cover. The front is expected to gradually
move southward tonight, but may stall as it moves closer to the
coastal plains region. Cold air advection behind the boundary will
keep lows in the lower 40s over the Hill Country and southern
Edwards Plateau, with temperatures closer to 60 degrees in the
Winter Garden and coastal plains. Low clouds will be widespread
tonight and with gradual cooling of the boundary layer and the warm
air advection pattern expected to strengthen, we should see at least
patchy fog and drizzle develop after Midnight across most of the
region. Coverage of fog and drizzle may need to be increased pending
observational trends this evening. Clouds remain thick on Monday and
with north winds likely in place for the region, high temperatures
will remain below normal. Highs will be in the lower to mid 50s over
the Hill Country and southern Edwards Plateau, with upper 50s to mid
60s elsewhere. Some modification of the air mass could lead to
warmer temperatures over the Winter Garden and coastal plains if the
latest HRRR pans out. For now, prefer to keep temperatures on the
cooler side of guidance (NAM12) given expected cloud cover and
northerly winds.
For Monday night, a shortwave trough embedded in the southwest flow
aloft will approach from the west. Rain chances will expand from
west to east across most of the region as this system draws closer.
Some elevated instability could also lead to an isolated
thunderstorm or two, mainly across the southern Edwards Plateau and
Hill Country.
&&
.LONG TERM...
(Tuesday through Sunday)
Issued at 222 PM CST Sun Feb 9 2025
Key Messages:
- Rain and thunderstorm chances during Tuesday and Wednesday
- Uncertain temperature forecast pending placement of front from
Tuesday into Wednesday
- Shots of much cooler and drier air by Wednesday night and again
late Saturday
A more active upper level pattern establishes during the long term
period as several shortwave disturbances advance into and through
the southern plains. Additionally, a series of fronts become key
features as well.
The time period from Tuesday into Wednesday could be tricky as the
shallow cold front that is advancing across the region today will
remain a factor within the forecast. The majority of the global
models are indicating the front could lift northward across the
region as a warm front by early Tuesday morning, which will result
in the return of a warmer and more humid southerly flow. However,
the NAM, Texas Tech WRF, and ECMWF AIFS indicate that the front
could remain stuck closer to the gulf coast with little northward
progression into our region. This solution would keep the cooler
airmass in place with a continued mainly northerly flow. If the
warmer solution verifies where the front advances north of the area
as a warm front into Tuesday morning, the passing shortwave then
influences the front and helps to surge the front back southward
through at least the northern portions of our area during Tuesday
evening into early Wednesday. Elected to trend the temperature
forecast within the middle of these two camps for now. We`ll make
additional adjustments as details evolve on the correct camp of
guidance.
Regardless of the position of the front, the combined forcing from
the passing shortwave and that nearby frontal boundary will promote
medium to high (50-70%) chances for showers along with occasional
thunderstorm activity from Tuesday into Wednesday. Activity may
focus between a few separate rounds. One round may be from Tuesday
morning into the early afternoon while a second round may occur
overnight Tuesday night into Wednesday morning. Forecast rain
amounts across the eastern 2/3rds of the CWA should generally range
from around a quarter to three quarters of an inch with localized
higher amounts in excess of one inch. Rain shifts east by the
afternoon on Wednesday.
Once the rain ends, another cold front plunges south across the
state with the help from strong surface high pressure building over
the plains. The front looks to arrive sometime from late Wednesday
afternoon into Wednesday night. The front is expected to advance
across the region as a dry passage. A much cooler and drier airmass
filters into the area behind the front`s passage with the moderate
to breezy northerly winds. A much cooler start will be expected
Thursday morning, including across the Hill Country where a light
freeze will be possible. Highs on Thursday will only range from the
mid to upper 40s into the 50s throughout the region. There may be
just enough weak isentropic ascent following the front to produce a
low chance of light rain or drizzle between early Thursday morning
and midday. Conditions dry out through the rest of Thursday with
another chilly night expected on Thursday night. The Hill Country
may see the potential for another light freeze while overnight lows
in the mid 30s to the low 40s are forecast elsewhere.
The temperatures modify Friday into Saturday as winds do eventually
shift back from out of the south. However, with the approach of
another shortwave, a third cold front within the long term advances
across the region sometime late in the day on Saturday. This front
could produce a slight chance of rain across our far eastern most
counties, otherwise the front looks to trend as a mainly dry
passage. A cooler and drier airmass filters back into the region
behind this front from Saturday night into Sunday.
&&
.AVIATION...
(00Z TAFS)
Issued at 552 PM CST Sun Feb 9 2025
MVFR cigs partially eroded from DRT to SSF, but should spread south
again in the next hour or two as the frontal surge strengthens with
elevated boundary layer winds. This steady wind should help keep most
skies with an MVFR cig through most of the night. Toward morning the
wind could lay down some and allow for cigs to drop to IFR. Light
overrunning could promote patchy drizzle, but will leave what the
earlier shift had and adjust when the early rounds of the 00Z model
runs arrive. Current thinking is that the IFR cigs will coincide with
some drizzle, but most of the drizzle could stay north of the
terminals until the inversion becomes more shallow toward the end of
the TAF periods.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 47 56 54 68 / 0 10 50 60
Austin Bergstrom Intl Airport 48 57 55 68 / 0 10 50 60
New Braunfels Muni Airport 49 58 57 73 / 0 10 30 30
Burnet Muni Airport 43 52 52 64 / 0 10 50 70
Del Rio Intl Airport 54 63 60 79 / 20 30 20 10
Georgetown Muni Airport 45 53 52 64 / 0 10 50 80
Hondo Muni Airport 51 62 58 75 / 0 10 20 30
San Marcos Muni Airport 48 57 56 71 / 0 10 40 40
La Grange - Fayette Regional 51 61 56 71 / 10 10 30 70
San Antonio Intl Airport 50 59 58 74 / 0 10 30 30
Stinson Muni Airport 52 62 59 75 / 0 10 20 30
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term...Platt
Long-Term...Brady
Aviation...18
Area Forecast Discussion
National Weather Service Sioux Falls SD
520 PM CST Sun Feb 9 2025
.KEY MESSAGES...
- Confidence remains high that snow will impact the area by
daybreak Monday and continue into Monday evening. A band of 1
to 3 inches appears likely with a moderate (40%) potential
for locally higher amounts. However, uncertainty remains in
exactly where the band will be focused.
- Temperatures remain below normal through the week, with
multiple days of below zero lows likely. The coldest lows
(from -5F to -20F) are favored Tuesday and Thursday mornings,
with Cold Weather Advisory level wind chills possible.
- A few snow chances remain Wednesday and Saturday, but trends
continue to place the greatest risks over Nebraska and central
Iowa.
&&
.DISCUSSION...
Issued at 310 PM CST Sun Feb 9 2025
TONIGHT-MONDAY EVENING: A sunny afternoon is giving us a good
satellite view of our current fresh snowpack, which covers
roughly east of the James River Valley (Huron-Mitchell-Yankton)
in southeast SD, across all of southwest MN & the far northwest
corner of IA. A look at afternoon temperatures shows the impact
of this snow cover, with readings there in the upper teens-mid
20s, while snow-free areas have warmed into the upper 20s-mid
30s. These areas will also be the quickest to cool this evening
as we lose insolation and winds become light, but anticipate
that increasing clouds ahead of our Monday snow system will help
slow the fall after midnight, with many areas potentially
seeing temperatures rebound slightly by daybreak.
Attention then turns to our next chance for snow, which will
impact the area possibly as early as late tonight, but mostly
during the daytime hours on Monday. Leading edge of a subtle
mid-level wave will result in warm advection and increasing
700mb frontogenesis into our far western counties after 06Z.
While initial lift will work to saturate the column, locations
west of I-29/north of I-90 may begin to see some light snow
begin prior to daybreak.
Main show will take place beginning mid-late morning as the
850-700mb frontogenesis begins to slowly pivot southeastward.
Unfortunately, still seeing disagreement in placement of the
forcing, with GFS remaining largely south of I-90 while the
Canadian model continues to favor areas north of I-90. The
NAM/NAM3km has trended farther south than its previous run,
which has some support from the RAP as well. Given slightly
better consensus between these solutions along with a slight
trend toward the GFS, have favored these in drafting pops, which
will place a band of light to moderate snow near to just south
of I-90 through much of the afternoon before more quickly
sliding off to the southeast through the evening.
Challenges with this system are multi-faceted. First, given the
broadly varying location of the expected band, any blended QPF
solutions are "watering down" the peak potential which the HREF
localized probability-matched mean (LPMM) shows our total QPF
peaking above 0.15". While location may be in question, did
nudge our QPF up to near this level within the aforementioned
area near/south of I-90. Second, snow:liquid ratios are tough to
pin down. Latest models continue to show a deep dendritic layer
with little wind to break apart the aggregating snowflakes.
Strongest lift is in the top 1/3 to 1/2 of this deep DGZ for at
least a few hours, which will also aid in very efficient snow
production despite relatively low QPF. This all means that very
dry/fluffy snow may pile up very quickly, resulting in what
seems to be at least a moderate (40%) potential for snowfall
exceeding 3 inches in some areas. Given the uncertainty in
location, will forgo issuing any headlines on this shift, but a
short lead time Winter Weather Advisory may be needed at some
point as the location of the heavier band becomes more clear.
MONDAY NIGHT-TUESDAY: With another round of fresh snow under our
belt as skies begin to clear late Monday night, will again see
optimal radiative cooling conditions and have nudged low temps
even farther downward toward the coldest available guidance
given what we saw with similar conditions this morning. This
will lead to lows from -5F near Hwy 20, to as cold as -20F
along portions of Hwy 14. Even a light breeze will push wind
chills to Cold Weather Advisory levels, most likely along and
north of I-90.
WEDNESDAY-SUNDAY: A couple more systems are slated to impact the
central-northern Plains from mid-week into the weekend, first on
Wednesday and the second later Friday into Saturday. Ensembles
continue to show moderate to high probabilities for measurable
precipitation/snow with the highest chances focused along and
south of Highway 20 with each system. The wave Wednesday will
bring a reinforcing shot of cold air, which similar to Monday
night, will push lows in to the teens below zero by Thursday
morning, with areas of advisory level wind chills expected.
Little moderation in temperatures is seen as we head into the
middle of February next weekend. However, given that this time
of year holds some of our coldest temperature records, we are
not looking for any record-setting cold with any of these waves
of arctic air.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 515 PM CST Sun Feb 9 2025
VFR conditions expected through night, before a band of light
snow begins to develop through the northern James River Valley
toward 12Z on Monday. This band will expand to the south and
east during the day on Monday. Although uncertainty remains as
to where the band will set up through the day, the current
thinking is that highest snowfall amounts will reside along and
south of the Interstate 90 corridor. Ceilings will lower into
the MVFR range with the onset of the snow, with MVFR and IFR
visibilities in falling snow. Winds will be mainly light
northerly through much of the TAF period, though begin to pick
up a bit on Monday afternoon.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
DISCUSSION...JH
AVIATION...JM
Area Forecast Discussion
National Weather Service North Platte NE
542 PM CST Sun Feb 9 2025
.KEY MESSAGES...
- Bitter cold temperatures will move into the area beginning Monday
and persisting through Wednesday.
- Potential for minor impacts from periods of light snow Monday
afternoon through Tuesday. Snowfall amounts will mainly be an
inch or less.
- A more significant system will affect the southern half of the
area Tuesday night into Wednesday. Snowfall amounts of 2 to 4
inches are possible across portions of southwest and central
Nebraska.
&&
.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 319 PM CST Sun Feb 9 2025
Tonight, an upper trough will dig south into the Northern
Plains. This will drive an arctic front southward into northern
Nebraska. This will bring lows of 5 to 10 above across much of
north central Nebraska. Strong surface high pressure near 1052mb
will become centered over southern Alberta Canada by daybreak.
The next potential for light snow accumulations arrives late Monday
morning and continues into Tuesday as an upper trough persists across
the Northern Plains and drives arctic air southward through
western Nebraska by late Monday afternoon.
Total snowfall amounts have increased slightly from the previous
forecasts. The latest 3km NAM and 18Z HRRR shown an area of
weak frontogenesis Monday afternoon across eastern Cherry
County through Boyd and northern Holt County with snowfall
amounts from a half inch to an inch. Monday night into Tuesday,
snow remain likely across the west and south, though additional
snowfall amounts are expected to remain an inch or less. Highs
Monday will be cold in the upper teens far northern Nebraska,
while southwest and central Nebraska reach the mid 30s before
the arctic front moves through late afternoon. Monday night will
be bitterly cold from 4 below to 4 above. Lowest wind chills
from 10 below to near 15 below with a northeast wind 10 to 15
mph.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 319 PM CST Sun Feb 9 2025
A more significant system arrives Tuesday night into Wednesday
and will bring the potential for moderate snow accumulations.
The main upper trough axis will cross the Central Rockies
Tuesday and across Nebraska and Kansas Tuesday night into
Wednesday. A coupled 300mb jet is indicated by the GFS. The
northern jet axis will extend across northern Nebraska across
southern Minnesota and Wisconsin, while the southern jet axis
will extend from southwest Texas across southeast Oklahoma and
southeast Missouri. This will provide an area of upper level
divergence across Kansas and southern Nebraska. While PWATs
will be modest from a quarter to a third of an inch across
southern Nebraska, SLRs will be highs near 20 to 1. Forecast
snowfall amounts will be 1 to 3 inches south of an Ogallala
through Burwell line, possibiliy near 4 inches across the far
southeastern zones. The GFS showed a slight shift southeast with
the precipitation shield, while the ECMWF shifted slightly
further north. Forecast confidence is average with snowfall
amounts, though amounts are likely to change the next day or
two.
Very cold Tuesday and Wednesday with highs in the teens. Wind
chill values as low as 10 to 15 below during the nighttime and
morning hours.
Mainly dry conditions Wednesday night through Thursday night as
a deep upper trough moves into California, and upper ridging
builds into the region.
Another chance for snow Friday night into Saturday, mainly
across the south, as an upper trough crosses the region.
Highs next Thursday are forecast to moderate to the mid 20s to
low 30s and 30s Friday. Snow chances return Friday into
Saturday. Turning colder Saturday and Sunday.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 540 PM CST Sun Feb 9 2025
For the KLBF terminal: Clouds will increase, beginning Monday
morning with broken ceilings ranging from 9000 to 12000 FT AGL
most of the day on Monday. Ceilings will fall off to around 5000
FT AGL late Monday afternoon. For the KVTN terminal: Clouds will
increase this evening with broken ceilings around 10000 FT AGL
tonight. Ceilings will fall further early Monday morning with
ceilings ranging from 1500 to 3000 FT AGL. Light snow will be
possible at the terminal, beginning mid morning with
visibilities down to 3 SM.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...Roberg
LONG TERM...Roberg
AVIATION...Buttler
Area Forecast Discussion
National Weather Service Marquette MI
925 PM EST Sun Feb 9 2025
.KEY MESSAGES...
- Scattered lake effect snow showers are expected over the
northwest to west wind snow belts through Tuesday night.
- Heavier lake effect snow is expected in the Keweenaw tonight
through Monday. A Winter Weather Advisory is in effect for
Keweenaw County during the night and for northern Houghton
County through Monday for 3 to 6 inches of accumulating snow
with isolated amounts near 10 inches.
- Below normal temperatures this week. Single digit highs on
Tuesday with lows near -20F by Wednesday morning are expected
in the west.
&&
.UPDATE...
Issued at 922 PM EST Sun Feb 9 2025
Water vapor imagery and RAP analysis show a couple of shortwaves
moving eastward vcnty of the International Border, one moving over
northern Lake Superior and a second over far se Manitoba. LES over
Lake Superior has been on the increase this evening due to the first
wave. Convergent westerly flow over western Lake Superior is
resulting in a convergence zone into Keweenaw County currently. Note
02z obs showing wind at Devils Island at 220 direction at 21kt while
Rock of Ages is 300 at 16kt. Shuniah radar from just outside of
Thunder Bay, ON shows a dominant LES band with mdt/hvy snow
streaming into Keweenaw County due to the convergence. High res
Canadian model has a good handle on the band, and only suggests very
slow southward movement during the night, which would delay heavier
snow onset in northern Houghton County. So, this band may spend
several hrs near the Houghton County-Keweenaw County line. Opted to
include Keweenaw County in winter wx advy thru 12z for 3-7 inches of
snow during the night. If band ends up becoming stationary for a
good portion of the night, snow accumulations upwards of 10 inches
or so not out of the question in a narrow zone cutting across the
Keweenaw Peninsula. Additional forcing from the second shortwave
will support continued mdt/hvy snow with the convergent band as it
drifts s overnight into early Mon.
Looking thru Mon, another shortwave will be heading e and reaching
western Lake Superior Mon evening, providing forcing for another
uptick in LES intensity. Overnight shift will have a chance to
peruse all of the 00z guidance to determine whether any advys will
be needed into Mon evening.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 245 PM EST Sun Feb 9 2025
Latest visible satellite imagery and radar reflectivity reveal light
wnw LES bands across northern sections of the U.P this afternoon.
Temps have been pretty chilly with readings generally stuck in the
teens under partly to mostly cloudy skies.
Tonight, a shortwave noted upstream on water vapor imagery hugging
the MN/Canadian border is fcst to move across northern Lake Superior
later this evening. While the best forcing from this shortwave
appears to stay north of Lake Superior there is some weak forcing
and deeper moisture that moves across the lake. This forcing/deeper
moisture combined with 850 mb temps of -18/-19C will result in
better organization of LES tonight. Also, winds backing to a
westerly direction along with sharpening of the lake induced trough
will enhance low-level convergence, especially over the western
portion of the lake, while providing the focus for a dominant w-e
LES band to form across the Keweenaw Peninsula. BUFR fcst
soundings for CMX show a pretty good crosshair signature of
low-level forcing/convergence within the DGZ which should be
favorable for snow growth and fluffier snow accumulation. High
resolution models show mean pcpn values close to 0.4 inch
centered mainly over northern Houghton County through 12Z
Monday. These qpf values combined with SLRs close to 20/1 should yield
LES accumulations of 3 to 6 inches through tonight. While it
looks like there is a potential for the LES band over the
Keweenaw to weaken somewhat during the day on Monday due to
weakening low-level convergence, there should still be a few
inches of additional accumulation through the day on Monday.
Thus, the Winter Weather Advisory for northern Houghton County
has been extended through 00Z Tuesday with total LES
accumulation from 3-6" and local accumulations up to 10".
Decided not to issue any headline yet for the Alger-Luce
counties as there is some uncertainty on the timing of when the
dominant LES would shift onshore there and how organized it
would be. It looks like the LES band, at the earliest, would
move in late tonight (09Z or after) so will let the midnight
shift fine tune the details of that potential headline.
Elsewhere across the U.P tonight, winds backing to a more west or
west-southwest direction will probably allow for more clearing to
take place. Generally have min temps dropping into the 5 to 10F for
northern shoreline areas which will see more clouds and varying
intensities of LES, while areas farther inland will see readings
dropping near zero and perhaps in the single digits blo zero over
the typical cold spots of the interior west.
&&
.LONG TERM /MONDAY THROUGH SUNDAY/...
Issued at 334 PM EST Sun Feb 9 2025
Precipitation through the early and middle part of this week will be
largely driven by Lake Superior. Thursday, a deepening trough
swinging across the central CONUS brings a chance for synoptic snow
on the backside of a sfc low tracking northeast from the southern
Plains into New England. At this time there is still uncertainty on
qpf/snow amounts skirting across the eastern half of the forecast
area, however, impacts appear to be low. An active pattern continues
into the following weekend, where additional chances for system and
lake effect snow are on the table. Temperatures this week will
continue below normal for early-mid February, supporting chilly
overnight lows and increasing ice growth in the Upper Great Lakes.
Beginning Monday morning, a positively tilted shortwave extends from
the North Dakota/Canada border northeast towards James Bay. At the
surface, a weak sfc trough extends from Lake Superior into Northern
Ontario while high pressure builds into the Ohio River Valley. In
turn, this will continue west wind lake effect snow through Monday
evening, focusing snowbands into the Keweenaw and far northeast UP.
The Winter Weather Advisory for northern Houghton county was
expanded through 00z Tuesday. Expect 3-6 inches of fluffy LES with
isolated amounts closer to 10" by Monday evening. This could
possibly be upgraded to a Winter Storm Warning or be expanded
further into Tuesday morning based on trends and observations
tonight. Elsewhere, 3-6" of fluffy LES is likely in far northeastern
Alger County and northern Luce county.
Monday night, the aforementioned shortwave pivots across Lake
Superior, sending a cold front across the forecast area and veering
winds to the northwest. The resurgence of cold 850mb temps between -
23 and -26C will reinvigorate LES in the NW wind snowbelts,
producing an additional 1-3" of fluffy ~20:1 SLR snowfall in the
Keweenaw and east half Tuesday morning. At the same time, surface
temperatures are expected to drop through Tuesday night, reaching
below zero area wide and dipping into the negative teens to near -20
for the interior west and central cold spots early Wednesday
morning. Though winds should be relatively calm away from the
lakeshores, wind chills could reach as low as -30F for portions of
the interior west.
Brief high pressure passing through the Upper Great Lakes Wednesday
will keep light lake effect snow showers confined to the Keweenaw
before ultimately pushing bands offshore. The next item of interest
arrives late Wednesday through Thursday as a deepening trough across
the central CONUS stirs up a sfc low, which travels from the
southern Plains northeast through the Lower Great Lakes into New
England by Thursday evening. Guidance over the last 24 hours has
trended ever so slightly northward and a touch faster with the sfc
low pressure placement by 12z Thursday, however, ensemble are still
in disagreement with the progression of the sfc feature and
associated precipitation shield across the Great Lakes. Euro
ensemble low-center clusters favor a faster system, placing the low
center nearly between lakes Erie and Ontario, while GEFS members lag
behind over Lake Erie into central Ohio. Thus, ensemble probability
for a widespread 1" of snow through Thursday evening remains
relatively low (20-50%) and confidence remains lower. What does look
increasingly likely is lake effect snow for the W to NW wind
snowbelts Thursday evening into Friday given a punch of 850mb temps
~-20-24C, though the window for accumulating snow appears narrow.
With increasing spread in model guidance, favored the NBM Friday
afternoon onwards. Some widespread light snow is possible over the
weekend and ensemble guidance has seen a slight uptick in the past
24 hours, increasing 1"/24hr probabilities to around 40-80% now.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 645 PM EST Sun Feb 9 2025
A passing disturbance will cause an increase in lake effect shsn off
of Lake Superior tonight under a W to WNW wind. At IWD, wind
direction won`t be favorable for the shsn, but initial VFR will give
way to MVFR cigs by late evening. A few flurries will also be
possible overnight into Mon morning. The MVFR cigs at IWD should
persist thru Mon aftn. At CMX, as lake effect shsn increase in
intensity during the mid and late evening, MVFR will fall to IFR,
then LIFR will prevail overnight. Conditions will likely fall to
airfield landing mins at times. IFR should be the rule on Mon though
gusty winds to 25-30kt may produce enough BLSN for ocnl LIFR. At
SAW, westerly wind will not be favorable for lake effect shsn.
Expect VFR to prevail though there may be ocnl high end MVFR cigs
late Mon morning/aftn.
&&
.MARINE...
Issued at 334 PM EST Sun Feb 9 2025
West-northwest winds 15-25 kts this evening briefly lower to 15-20
kts by Monday morning, but increase again to 20-30 kts by Monday
afternoon with a passing cold front. Probability of gales to 35 kts
have continued to increased to 40-80% for the passing cold front,
mostly over the east half of the lake. Northwest winds fall to 20
kts Tuesday morning, backing west by Tuesday evening as they settle
below 20 kts. Southwest winds less than 20 kts are expected on
Wednesday. A cold front on Thursday brings back northwest winds of
15-25 kts into Friday.
Otherwise, freezing spray is expected over the east half of the lake
into tonight and across much of the lake Monday afternoon into
Tuesday. Some heavy freezing spray is possible Monday night (~50-60%
chance).
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Winter Weather Advisory until 7 AM EST Monday for MIZ001.
Winter Weather Advisory until 7 PM EST Monday for MIZ003.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
UPDATE...Rolfson
SHORT TERM...Voss
LONG TERM...BW
AVIATION...Rolfson
MARINE...BW
Area Forecast Discussion
National Weather Service Raleigh NC
955 PM EST Sun Feb 9 2025
.SYNOPSIS...
A cold front will move south across the Carolinas tonight and stall
across the Deep south on Monday and Tuesday. Cold shallow high
pressure will wedge into our region late tonight and remain in place
as moisture repeatedly overspreads the area through late in the
work week.
&&
.NEAR TERM /THROUGH MONDAY/...
As of 955 PM Sunday...
As of 02Z, the surface low was centered near Charlotte, with the
front extending esewd along the NC/SC border. Surface winds across
central NC are mainly nely, advecting drier air into the area from
the northeast, however the cold air has been slow to arrive, owning
to the presence of the surface low and attendant front draped across
the NC/SC border.
A shallow, sloped f-gen band between 925mb and 850mb W-E across
cntl/srn portions of the area will continue to shift slowly ewd then
sewd through tonight. A weak mid-level perturbation will continue
moving across the area this eve/early tonight. Showers have
developed and generally moved ewd along the front, with some
scattered showers and light rain spreading ewd across the area to
the north of the front. As the surface low progresses ewd along the
front and offshore through tonight, the high will finally begin to
build swd into the area, finally pushing the rain out from WNW to
ESE Mon morn. Lows tonight still expected to drop into the mid/upper
30s across the northern half of central NC, with lingering low
(possibly some mid) 40s across the south. -KC
From the previous discussion (as of 204 PM): The cold front will
continue to progress south and southwest through Mon, reaching
central sections of GA by Mon afternoon. A CAD wedge will setup as
1034 mb high pressure currently over the Midwest settles into the OH
valley and noses down into central NC.
As cold air advection at and below 850 mb commences early Mon
morning, soundings show a very small window before precipitation
ends where a little sleet could mix in along the far northeast
Piedmont and near Roanoke Rapids. No impacts are expected and most
areas will not see anything frozen. Overnight lows tonight will
range from the mid 30s in the NE to the low 40s in the SW.
Precipitation is expected to taper off from northwest to southeast
by mid to late morning. Low clouds are likely to linger for much of
the day, with only partial clearing possible by the mid to late
afternoon as the wedge remains in place. Highs will be much cooler
than Sun and below normal by about 6 to 12 degrees in the mid to
upper 40s. -Kren
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
As of 245 PM Sunday...
* Risk of impactful wintry precipitation on Monday night/Tuesday
morning and Tuesday night has decreased somewhat.
* After a lull on Monday evening, a light wintry mix may develop
late Monday night across northern areas as precipitation
redevelops. A few patches of freezing rain is possible for a few
hours during the mid to late morning across the northern parts of
the Triad and VA border counties.
A progressive Arctic surface high that will be centered across OH/PA
on Monday evening will quickly shift east and off the NJ coast
toward midday Tuesday. The high will extend into the Carolinas and
provide an initial feed of colder and drier low level air into
the region. After a period of dry weather and some improvement
in sky condition on Monday evening, low level isentropic lift
will quickly develop across the Carolinas around midnight and
strengthen resulting increasing clouds overnight. Light
precipitation will break out toward daybreak across southern and
western areas. Surface wet bulb temperatures are around or just
below freezing during the early to mid morning in the Triad and
VA border areas which could result in a period of light
freezing rain during the morning toward midday. Given this would
occur during daylight hours when freezing rain accrual is less
efficient especially with marginal temperatures, expect this to
be a low impact event in the RAH CWA with patchy accruals a
trace to a hundredth or two of freezing rain. Note while the
15Z RAP soundings and the 12Z NAMnest highlight surface
temperatures at or above freezing, the warm nose at 850 to 800
mb doesn`t warm up to 2 or 3C until midday meaning there could
be a short period of snow or sleet at the onset but this should
be brief and likely mixed with freezing rain or rain. As the
surface high shifts offshore, the boundary layer should warm
just enough into the afternoon to end the threat of freezing
rain with a cold rain continuing across much of central NC
during the afternoon. The most widespread and steadiest rain is
expected across the northwest and northern Piedmont with the
rain a little lighter and perhaps intermittent at times across
the south and southeast. Morning lows on Tuesday will range from
32F across the north to 38 across the south. Highs on Tuesday
will range in the mid 30s in the damming region in the Triad
and VA border counties to the lower 40s across the south
including Fayetteville.
Periods of rain will continue on Tuesday night into Wednesday as a
strong frontal zone persists to the south of the area and periods of
warm advection and isentropic lift spread across the area. Rain
coverage and rates will relax on Tuesday evening before another
surge of precipitation spreads across the late late Tuesday
night into Wednesday. Surface temperatures should largely
remain above freezing on Tuesday night into Wednesday. Given
the displacement of the surface high from a favorable location
and despite some enhanced flow on the backside of a departing
surface wave, do not see a good mechanism to draw a significant
enough amount of cold dry air to change the predominate
precipitation type to freezing rain. Lows Tuesday night will
range from 33F in the north to around 40 in the south. Highs on
Wednesday will range from the upper 30s to lower 40s in the
damming region to the lower to mid 50s across the Sandhills and
southern Coastal Plain. -Blaes
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 204 PM Sunday...
As the rain continues Wednesday evening, a low pressure is expected
to develop off the SC/NC coast. With CAD conditions in place
Wednesday night, expect this to quickly erode as WAA moves up from
SC along a warm front boundary dangling from the coastal low across
the Carolinas. As the coastal low moves NE and more offshore a cold
front will follow through the region bringing more rain Wednesday
night into Thursday. At times, heavy rain could occur resulting in
some rainfall accumulations in low lying and urban areas. Rainfall
totals for Wednesday evening through Friday morning range from just
over an inch in the Northern Piedmont to 0.75 across the Sandhills
and Coastal Plain. P-type should not be an issue Wednesday and
Thursday as temps Wednesday night will warm through the night (WAA)
lows ranging from near 40 in the north to near 50 in the south.
Warming trend will continue through the day as the warm front lifts
across the region, with highs on Thursday in the upper 50s north to
upper 60s maybe a few spots seeing 70s degrees across the south.
Thursday night a cold front moves across the region as an arctic
surface high builds across the Central Plains and into the Mid-
Atlantic. While the precip is expected to move out of the region by
early Friday, the dry cold air will move in behind with Fridays
morning temperatures in the low 30s north to upper 30s south. Mostly
sunny skies with NE flow will keep temperatures generally in the mid
40s north to low 50s south. Cold air will continue to filter in
during Friday evening with lows overnight being the coldest of the
forecast period. Generally expect upper 20s near the VA border and
mid 30s in across the south.
Another weather system will make its way from the Pacific NW Friday
and into the Mid-Atlantic region Saturday morning. A warm front
boundary along the gulf will lift across the region Saturday
bringing another round of rain for most of the day. Following the
warm front, a cold front will move across the MS Valley and across
the Mid-Atlantic region Sunday afternoon/ early evening. Thus expect
another wet weekend ahead. Again, P-type is not expected to be an
issue at the time with highs in the 46-64 range Saturday 40-49
degree range Sunday night, and 56-70 degree range Sunday.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
As of 715 PM Sunday...
24-hour TAF period: VFR conditions will largely prevail across
central NC at the very start of the period this evening, as a band
of light rain spreads in from west to east but initially falls from
5-10 kft ceilings. However, ceilings will lower to MVFR at all
terminals from about 04z to 07z, then IFR shortly after that. The
one exception is FAY, which may not reach IFR until Monday morning,
and there is lower confidence it gets there at all, as the heaviest
and steadiest rain will be across the north. There is even a chance
for LIFR ceilings at the northern terminals (INT/GSO/RDU/RWI), with
the best chance early Monday morning, but model consensus is not
strong enough to warrant including in the TAFs at this time. Rain
will exit the area from NW to SE from about 12z to 18z, with
visibilities improving to VFR, Ceilings should lift to MVFR
everywhere by early afternoon. Skies will begin to clear and VFR
will return by mid to late afternoon from north to south. Winds will
largely be from the NE around 5-10 kts through the period.
Outlook: A brief period of VFR will continue into Monday night. A
wet and unsettled pattern with prolonged CAD conditions will then
return Tuesday and result in periods of adverse, sub-VFR
restrictions through late week. Additionally, a period of freezing
rain is possible at KINT and KGSO Tuesday.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Blaes
NEAR TERM...KC/Kren
SHORT TERM...Blaes
LONG TERM...CA
AVIATION...Danco/Kren