Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/09/25
Area Forecast Discussion
National Weather Service Bismarck ND
900 PM CST Wed Jan 8 2025
.KEY MESSAGES...
- Light precipitation is expected across western and central
North Dakota tonight through early Thursday morning. A mix of
snow, rain, and freezing rain is possible along the leading
edge of the system, with a transition to all snow.
- Breezy to windy conditions are also expected through Thursday
afternoon, which could create patchy blowing snow.
- There is a 60 to 80 percent chance of accumulating snow across
western and central North Dakota Friday night into Sunday,
with low to medium chances of at least 3 inches.
- Temperatures are favored to fluctuate between below and above
normal through next week, with Monday likely to be the coldest
day.
&&
.UPDATE...
Issued at 900 PM CST Wed Jan 8 2025
Weak to moderate reflectivities continue to cross across
western North Dakota at the time of this update, with the most
consistent precipitation found across the northwest. Much of
this precipitation is falling as light snow, though a few
pockets of rain/freezing rain has been observed this evening,
most notably around Williston. A general transition to all snow
is still expected as we approach the early overnight period.
Have adjusted PoPs slightly to account for more long- lasting
precipitation across the north. Otherwise, the forecast remains
largely on track.
UPDATE
Issued at 535 PM CST Wed Jan 8 2025
Low level clouds and precipitation are beginning to move into
western North Dakota this evening, with the occasional rain drop
evident on NDDOT cameras in the northwest. At the same time,
however, light snow is beginning to be reported just over the
International Border at Estevan, Canada, which does show the
quicker transition to all snow posited by the most recent model
runs appears to be panning out. With a mix of precipitation
types still possible as we continue to cool through the evening,
we will continue to monitor this trend. Overall, the forecast
remains on track at this time.
&&
.DISCUSSION...
Issued at 132 PM CST Wed Jan 8 2025
Low pressure situated over the central Canadian Provinces with a
trough into the Northern Plains will track southeast bringing
warmer temperatures to the forecast area late this afternoon and
this evening. A shortwave tracking through the northern Rockies
is producing light rain over portions of northeast Montana this
afternoon. This precipitation is expected to move into western
North Dakota late this afternoon/early this evening and track
southeast across the forecast area through the night and exit
the James River Valley Thursday morning or early Thursday
afternoon.
Precipitation this afternoon is expected to be very light and
may result in mainly virga or sprinkles. Temperatures this
afternoon, south of the Big Lake are already mostly above
freezing, and those north of the Lake may climb above freezing
as well, so any impacts this afternoon are expected to be
negligible.
This evening, as the shortwave moves into eastern MT,
precipitation chances will increase across western and into
central ND. As atmospheric column cools, precipitation is
expected to become all snow. However, prior to this occurring,
there may be period where we could see, rain, and/or freezing
rain, or a mix of rain/freezing rain and snow before this
transition is complete. The 12 UTC model suite and cams through
the day have lessened the precipitation potential across the
northwest and especially the north central, but kept the high
potential over the west central into southwest ND. NBM qpf is
maximized over far west central ND, say around Trotters and
Beach and south into far southwest. Elsewhere qpf amounts are
generally less than a tenth of an inch, with lightest amounts in
the north central.
Snow amounts have backed off, with a half inch or less along
and north of the Highway 200 corridor, and a half inch to an
inch south of the Highway 200 corridor. There may be some areas
(Beach to Trotters) that see 1 to 2 inches but currently it
looks like only a few areas will see over an inch, with most
area seeing an inch or less.
There remains the potential for freezing rain, and rain with
this system this evening, before the transition to all snow.
With the shift in the heavier qpf more to the west central and
southwest, think there may be an increase in freezing rain
potential over the southwest, compared to yesterday and this
morning. The main question, is whether or not surface
temperatures drop back below freezing before precipitation
transitions to snow. To account for this, we kept a slight
chance of freezing rain over the southwest from mid to late
evening. If surface temperatures remain above freezing, we
should see a transition from rain to snow. If they would happen
to drop below freezing, then the freezing rain potential would
increase. Local research indicates that with light qpf amounts
(under a tenth of an inch) with a substantial warm layer aloft,
you don`t always see the wet-bulb effect and you can get a
surprise freezing rain event. The light qpf would fit with this
event for many areas south of the Lake, but I wouldn`t call this
a substantial warm layer aloft, with a max of around 2.5
degrees above freezing. Some of the later HRRR soundings are
showing quite a bit of warm air near the surface, and although
there is a nose of warm air aloft, the column cools from top to
bottom, yielding more of a traditional rain to snow transition.
If that turns out to be the case we`re golden. If not, we could
see at least a small chance of freezing rain mid to late
evening. Therefore we will keep a slight chance mention this
evening.
It will be breezy to at times windy tonight and there could be
some patchy blowing snow. However, the warmer temperatures west
and south central should help diminish this threat. This can be
seen in the blowing snow grids with a good portion of the
southwest not seeing any blowing snow, due to today`s warm-up.
For the most part, expect precipitation to be all snow after
midnight, and into Thursday morning. There are some indications
that we could see a loss of ice on the back side of the system
with the potential for some patchy freezing drizzle. However,
confidence in this is too low to mention and with the warmer
temperatures, impacts would appear to be minimal at this time.
Breezy to windy conditions are expected to continue through the
day on Thursday, with some steep lapse rates over the area
Thursday afternoon. There is some hint of some
afternoon/evening snow showers, and in areas around the Turtle
Mountains into the northern JRV, there may be enough loose snow
for some blowing snow Thursday afternoon/early evening. In
coord with Grand Forks, we added a slight chance of snow showers
Thursday afternoon/evening. The RAP does show some weak
instability but currently, the snow squall parameter is
maximized over far southeast ND, and southeast MT into northeast
WY. Will continue to monitor though.
We get a short break in the precipitation Friday, but the next
system is already beginning to move into the west by Friday
evening. This system is a combination of a Canadian clipper
system and West Coast trough that combine over the Northern
Plains. There are indications that the Pacific wave may take
more of a southern track, thus the overall snow totals have
diminished a little with generally low to medium chances of 2
or more inches of snow through the late Friday through Sunday
timeframe.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 900 PM CST Wed Jan 8 2025
Mainly VFR ceilings and visibility are found across all
terminals to begin the 00Z TAF period. Chances for precipitation
will increase from west to east through this evening, before
diminishing also from west to east late tonight. This
precipitation is expected to fall primarily as light snow,
though could be mixing in with some freezing rain (northwest) or
rain (southwest) through this evening. A general transition to
all snow is expected by late this evening. MVFR to IFR
ceilings and visibility is expected to accompany this snowfall,
with these lowered ceilings lingering across the forecast area
though much of the period. Some wrap-around precipitation,
again falling as light snow, is possible across portions of
central North Dakota Thursday afternoon, though confidence is
too low to include at any given TAF site at this time. The
passage of a cold front tonight is expected to induce a wind
shift to the northwest, becoming gusty with speeds from 20
knots and gusts up to 30 knots possible through the end of the
TAF period.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Adam
DISCUSSION...TWH
AVIATION...Adam
Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
558 PM CST Wed Jan 8 2025
...New AVIATION...
.SHORT TERM...
(Now through Thursday night)
Issued at 151 PM CST Wed Jan 8 2025
The short term forecast for Deep South Texas will feature well below
normal temperatures, breezy north winds, periods of light rain
and/or drizzle, and adverse beach/marine conditions.
Although some light rain/drizzle has developed over the immediate
coast today, most of Deep South Texas has remained rain-free due to
the overall lack of moisture content present. Still, persistent low
level southerly flow (~850mb) has maintained overcast skies as warm,
Gulf moisture overruns the significantly cooler airmass at the
surface. Meanwhile, the latest surface observations and RAP guidance
reveal a tightening pressure gradient in response to a deepening
coastal trough along the Lower Texas and Northern Mexico coast,
which is expected to develop into a coastal low late tonight into
Thursday morning.
We should begin to see an increase in precipitable water after
midnight tonight as the coastal low develops, ranging from 1.2
inches across the Northern Ranchlands to upwards of 1.5 inches
closer to the immediate coast. This should result in an uptick in
precipitation coverage for portions of Deep South Texas tonight. The
latest suite of high res guidance indicates the highest rain chances
(~60-80%) will reside mainly across Cameron, Willacy, and southern
Hidalgo counties, as well as along the immediate coast, which
coincides with the placement of the highest moisture content and
proximity to the coastal low.
The combination of overcast skies, brisk north winds, and increasing
rain chances will result in another chilly night, with lows ranging
from the mid to upper 30s across most of Deep South Texas, and
closer to the low to mid 40s across the Lower RGV and the Lower
Texas beaches. In combination with breezy winds, "feels like"
temperatures tomorrow morning will be in the low to mid 30s
region wide.
The coastal low is expected to track northward along the Lower Texas
Coast on Thursday, which should maintain northerly winds, overcast
skies, and continued precipitation chances through the day. High
temperatures will be similar to today, ranging from the low to mid
40s across the Northern Ranchlands to upper 40s across the Rio
Grande Valley. The latest suite of high res guidance does indicate
we should see a decrease in precipitation chances across the Rio
Grande Valley Thursday afternoon as the coastal low tracks
northward. However, rain chances will return region wide once again
Thursday night as large scale forcing associated with an upper level
trough/low, currently centered over the Desert Southwest, translates
east and northeast and interacts with favorable moisture content.
With temperatures expected to remain above freezing Thursday night,
winter precipitation is not expected at this time.
Otherwise, a high risk of rip currents due to increased winds and
seas will continue across the Lower Texas beaches.
&&
.LONG TERM...
(Friday through next Wednesday)
Issued at 151 PM CST Wed Jan 8 2025
Key Messages:
-Below normal temperatures expected through the long term.
-Rain chances taper off for the weekend but return for the workweek.
The long term period will begin with an upper level trough digging
into northern Mexico and moving through Deep South Texas on Saturday
while a surface low continues to move eastward into the SE US. As
this low pushes eastward rain chances will decrease as we head into
Friday afternoon with dry conditions expected through much of the
weekend. Temperatures will remain quite chilly on Friday with highs
in the low 50s. Friday night, temperatures will fall into the 30s
across much of the region and temperatures could drop to right
around freezing across Kenedy, Brooks, Jim Hogg and northern Zapata
counties. Will keep an eye on the potential for a Freeze
Watch/Warning, but at this time temperatures remain just shy of
criteria (32 or below for 2+ hrs). A warm up starts on Saturday with
highs in the upper 50s to around 60 degrees as southeasterly flow
returns. The warm up continues through the weekend but afternoon
highs will still remain shy of seasonal norms. Clearer skies
overnight will allow for radiational cooling and low temperatures at
least 5 to 10 degrees below normal.
Another upper level trough moving across the Plains will bring
another cold front through Deep South Texas late Sunday with cooler
air moving back in for next week. While temperatures will not be
quite as cold as the current cold snap, will still remain well below
normal. As the aforementioned front passes, a coastal trough will
set up in its wake bringing back rain chances through the remainder
of the long term period.
&&
.AVIATION...
(00Z TAFS)
Issued at 540 PM CST Wed Jan 8 2025
A widespread low cloud decks with ceilings between 3500 to 6000
ft, except MVFR ceilings at BRO, and moderate to gusty prevail
across Deep South Texas early this evening. Ceilings will continue
to lower through the evening with MVFR and then IFR late tonight.
Periods of light rain and/or drizzle and mist will start to
develop later this evening and continue through much of the
period. The best potential for rain and/or drizzle will be across
the Lower Valley, BRO and HRL. Reduced visibility of around 4SM
will be possible tonight and Thursday as pockets of light to
moderate rain/drizzle develops. Moderate to gusty north winds
early this evening will decrease through the evening and overnight
hours. Light to moderate north winds are expected to continue on
Thursday.
&&
.MARINE...
Issued at 151 PM CST Wed Jan 8 2025
Now through Thursday night...A tightening pressure gradient in
response to a deepening coastal low/trough will result in increasing
winds and rough seas over the Gulf waters and the Laguna Madre
through the period. As a result, a Small Craft Advisory is in effect
through Thursday evening for the Gulf waters and the Laguna Madre.
Periods of light rain and/or drizzle may result in reduced
visibility as well.
Friday through Tuesday...Adverse marine conditions will
continue off the lower Texas coast into Saturday morning. As a low
pressure system moves into the SE US winds and seas will decrease
Saturday with more favorable conditions returning by Saturday
afternoon. Another cold front will push through the waters off the
lower Texas coast late Sunday with winds and seas increasing in its
wake which will lead to Small Craft Advisory conditions beginning
Sunday night and lingering into the workweek. Rain chances will
continue through the period, briefly drying out on Saturday.
&&
.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE 40 51 43 52 / 90 70 90 50
HARLINGEN 39 48 39 52 / 70 70 90 40
MCALLEN 38 47 42 55 / 60 50 80 30
RIO GRANDE CITY 37 44 41 54 / 40 50 80 30
SOUTH PADRE ISLAND 48 57 48 55 / 90 80 90 60
BAYVIEW/PORT ISABEL 42 52 42 54 / 80 80 90 50
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk through Thursday afternoon for TXZ451-454-
455.
GM...Small Craft Advisory until 6 PM CST Thursday for GMZ130-132-135-
150-155-170-175.
&&
$$
SHORT TERM...22-Garcia
LONG TERM....68-McGinnis
AVIATION...63-KC
Area Forecast Discussion
National Weather Service Cheyenne WY
505 PM MST Wed Jan 8 2025
.KEY MESSAGES...
- High wind and blowing snow concerns continue through the evening
for the wind prone areas.
- New snow accumulations tonight and winds increase again tomorrow,
resulting in continued blowing snow potential. Light totals expected
in the valleys and plains (mainly around 1"), greater amounts in the
mountains (6"+).
- Another system brings widespread snow chances late Friday through
early Sunday as wintry temperatures stick around through early next
week.
- Milder conditions appearing more likely mid next week.
&&
.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 323 PM MST Wed Jan 8 2025
Quite the dynamic pattern has set up aloft with an anomalous ridge
just off the Pacific Coast bounded by a deep closed low over the
Baja. A trough over the Canadian Rockies is in the process of
digging into the Northern Plains, which will transition nearly
meridional flow over Wyoming to more west/northwesterly. Another
upper trough is centered over the Great Lakes. At the surface, an
expansive high pressure stretches from the Gulf Coast to the Pacific
Northwest. This high is anomalous as well, recording 1040mb over the
Rockies, and registering around the 99%ile of climo per NAEFS
ensembles. The surface pressure gradient supported high winds in the
prone areas again today.
This evening and tonight... A potent shortwave preceding the main
longwave trough cuts across the northern Rockies and High Plains,
while a surface cold front lines up to traverse the region. Behind
the front, the Northwest US lobe of surface high pressure expands
over the Rockies and again pushes 1040mb. These factors, along with
sufficient lift and moisture, will result in a new round of snow
shower activity and blustery winds. Used a general blend of HREF and
HRRR for coverage and timing of PoP, which is maximized 03-12z.
Thermal profiles would suggest a fairly drier snow, especially as
SLR`s surpass 12:1 over the Neb panhandle, 15:1 over the Wyo plains,
and 18:1 in the mountains. With northwesterly low level flow,
upslope is maximized over the Snowy and Sierra Madre ranges, east of
Laramie along the divide, and northern Dawes Co along the Pine
Ridge. Considering the progressiveness of the system and the lack of
overly abundant low level moisture, precip amounts should remain
light overall, with the exception of the mountains. A couple bands
of 1-2" snow totals are possible near the eastern Wyo ridges over
toward the Pine Ridge, while most of the plains and Neb panhandle
should stay under 1". Kept the Winter Wx Advisory for I-80 zones
from Cheyenne to Rawlins due to 6"+ totals in the higher terrain and
the continued blowing snow component. As for min temps, values will
be seasonable (10s, lower 20s) and hold well above this morning`s
observed temps (widespread subzero). Increasing cloud cover and
winds should insulate and mix the near normal -7C H7 temps.
Tomorrow... Snow showers continue through about midday, especially
the southeast half of the CWA. Northwest winds steadily increase
from sunrise to midday as 6hr surface pressure rises exceed 7mb and
an approaching PV anomaly pushes to 500mb. As opposed to a more
localized high wind setup experienced today, tomorrow supports a
broadbrushed blustery day across the region. Despite the widespread
breezy conditions, in-house wind procedures and NBM90 guidance fall
short of warning criteria. Peak gusts of 40-50 mph are anticipated,
especially east of the divide. Depending on the duration of the snow
shower activity, an extension or perhaps expansion of the Winter Wx
Advisory may be needed as more of the falling snow correlates to
greater wind speeds. Strong cold air advection in the wake of the
front and in the vicinity of the upper trough axis will keep max
temps chilly across the area. In fact, some guidance suggests a
steady or non-diurnal temp trend, so not expecting much recovery
after the snow showers dissipate. Trended forecast highs down toward
the cooler numerical guidance, which still registers near the 75%ile
of the NBM envelope. Temps range from single digits in the
mountains, upper 10s to 20s in southeast Wyo to near freezing in the
Neb panhandle river valleys.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 323 PM MST Wed Jan 8 2025
Northern Flow stays with us from Friday through the
weekend to keep overnight temperatures in the teens to single
digits. Friday night Saturday, a trough moves through our region as
an Alberta CLipper pushes through the Northern Plains. This trough
will push against the Pacific ridge sitting over the west coast
creating some pretty gusty winds. Looking at the Craig to Casper
height differences at 850 level those values range between 60 to 94
meters with the 94 meters peak occurring at 03z Saturday. The height
differences drop below 60 by Saturday afternoon. The local high wind
machine learning algorithm also keeps the probability for high wind
gusts near or slightly above 80 percent from Friday afternoon to
Saturday afternoon to increase confidence in warning criteria wind
gusts. Along with the faster winds, this trough is also expected to
produce some precipitation as well but, mainly for the mountain
ranges. For the the counties east of I-25, the probability for
greater that 0.25 inches of snow ranges from 10 to 20 percent on
Saturday.
Another shortwave moves through the area Sunday into Monday to give
us elevated wind gusts but not warning level criteria. Craig to
Casper heights remain in the 30`s and 40`s Sunday into Monday but
higher values are needed to see wind gusts to reach warning levels.
Given the continual North to northwest flow, the biggest uncertainty
is how much moisture is in the atmosphere come Sunday to support
light snowfall.
Tuesday and Wednesday, The Pacific ridge start to move close to the
Rocky mountains to raise temperatures back into the 30`s and 40`s.
The region also looks to remain relatively dry these two days as the
ridge continues to push east. Despite temperatures being in the 30`s
and 40`s during the day, temperatures look to remain in the teens
and single digits at night. Likely due to possible clear skies under
the ridge allowing for efficient radiational cooling.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 505 PM MST Wed Jan 8 2025
A fast moving upper level trough pushing south out of Canada will
move across the region tonight. This system will bring breezy
conditions and a quick shot of snow to the southeast Wyoming and
western Nebraska terminals between 03z and 16z tonight into early
Thursday morning.
HAZARDS/WEATHER TRENDS: Primary uncertainty tonight and early
Thursday is timing of the precipitation and IFR conditions. It is
awfully dry near the surface currently with dewpoints in the teens
and single digits at most places. Snowfall will likely be delayed
and not make it to the surface at first. Expect KRWL and KCDR to see
the snow and IFR conditions likely between 03z and 08z. Further
south towards KAIA and KSNY, activity will likely hold off until
after 09z. Conditions are forecast to improve rapidly between 15z to
18z Thursday.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Warning until 8 PM MST this evening for WYZ106-110.
Winter Weather Advisory until 6 AM MST Thursday for WYZ109-110-
115>117.
NE...None.
&&
$$
SHORT TERM...DS
LONG TERM...MM
AVIATION...TJT
Area Forecast Discussion...UPDATED
National Weather Service Peachtree City GA
631 PM EST Wed Jan 8 2025
...New 00Z Aviation Discussion...
.SHORT TERM...
(This evening through Thursday)
Issued at 345 PM EST Wed Jan 8 2025
Like yesterday the current satellite loop shows decreasing clouds
across NW GA with mostly clear skies across the rest of the state.
Surface high pressure is still slowly building into the area from
the Northern Plains through Thu afternoon with near zonal 500mb
flow. There is a weak dry cold frontal boundary that sweeps through
the state from NW to SE Tonight which will help to reinforce the
cold airmass over the area. Looking for temps Tonight to bottom out
in the teens along and north of the Interstate 85 corridor with
lower 20s elsewhere. High Temps Thu rebound mainly into the 40s with
some upper 30s across the N GA mountains. Thu will be our last dry
day this week as the next frontal system beginning to develop in the
western gulf Today will move NE and into our area Thu night into
Friday morning. Extreme western portions of the state will see some
light snow showers just before sunrise Fri morning but we will see
our winter weather mainly move in during the day Friday.
01
&&
.LONG TERM...
(Friday morning through next Tuesday)
Issued at 345 PM EST Wed Jan 8 2025
Key Messages:
- Primary impact continues to be winter weather on Friday into
Friday night. Greatest probability of impactful wx will be in
northern Georgia through metro Atlanta. Areas south of I-20
continue to remain a bit more uncertain.
- Snow looks to be primary precip time in northern Georgia and the
mountains as of this forecast package. Amounts look to be in the
3-6" range. Can`t rule out some mixing in of sleet or freezing
rain that could limit accumulations a bit in some locations.
- Precip type continues to look primarily frozen in the metro and
points east. Snow would be the onset precip type that could
accumulate and impact morning commute. A switch to sleet and/or
freezing rain would during the afternoon. Can`t rule out a brief
transition to rain.
- South of I-20, uncertain if we can remain below freezing during
the day on Friday. We will likely start during the morning hours
with snow, but this would quickly transition to rain.
Forecast:
Not too much change in the overall forecast with the update to this
forecast package. Starting to get access to some of the higher
resolution guidance, and it is painting a similar picture to what
the forecast has been thus far. Snow expected in the north, a
transition area in the metro and points east, including Athens,
and then for central Georgia an initial period of snow before a
quick transition to a cold rain.
Synoptic setup is as follows - cold air mass continues to linger in
the area during the day on Thursday. We will see another wave pass
by the area on Thursday aloft that will be dry, but will push a
reinforcing shot of cold air in on Thursday into Thursday night.
This will set the stage for winter precipitation on Friday, allowing
our surface air mass to be cold enough for some sort of frozen
precip. Two significant upper level features, a cut off low over the
desert southwest, and another shortwave quickly moving within the
polar jet, will phase together and eject into the southeast on
Friday into Saturday. Wave will interact with significant
baroclinicity in place across the Gulf coast with cold air settled
in place and generate strong surface low within region of PVA ahead
of it. This will bring precip and the potential for winter weather
across wide swath of the south, including our CWA.
Confidence remains high in seeing impactful snow accumulations
across northern Georgia. Ensemble guidance has come down a little
bit in totals in these areas, and this forecast package reflects
that a bit. A few things going on here - the biggest being models
seeming to be a bit warmer at the surface, as well as some models
seeming to better resolve a warm nose. Precip would likely start
during the morning hours, around or a bit after sunrise, and remain
snow for a good bit of the day, if not the entire day. Current
forecast amounts would be between 3-6" inches in this area. A
huge caution with looking at 10:1 ratio forecast maps - current
SLRs used in this package are closer to 5 and 6 to 1. Sounding
profiles are near isothermal for a good chunk of low levels and
approaching mid levels. This is likely to be a wet, heavy snow.
There is a chance that would could see some sleet or freezing rain
mix in, especially if some of the more aggressive guidance with
the warm nose occurs, which would act to limit accumulations to
the lower end of projections.
In metro Atlanta and points eastward, including Athens, we are
expecting to see several different phases of precipitation. The
initial onset during the morning hours looks like it should be
snow. Hi res models show significant drying in the low levels just
off the surface that will likely quickly adjust thermal profiles
to be below freezing in the entire column as initial snowfall
sublimates while falling. From there, a transition to sleet and
possibly freezing rain is expected to happen moving into the
afternoon. Big model discrepancy as to how quickly this transition
will happen. Latest HRRR (18Z), for instance, has come in with an
impressive solution that would likely pile up an inch or two of
snow in these areas before transitioning in the late afternoon as
the warm nose pushes into the area. Other models have even earlier
transition (for instance, 12Z 3km NAM) as warm nose in these push
in even faster. Right now, forecast expectations are 1-3 inches
of snow and/or sleet with the potential for a tenth to 2 tenths of
ice. Really want to emphasize an important point here - if models
which show earlier transition are right, there is absolutely
potential for a decent ice storm, with decrease in snow totals and
increase in ice totals. Please stay tuned to this portion of the
forecast.
Other bit of uncertainty is on surface temperatures in the metro and
areas east (and really south into central GA). We will need to find
a way to offset the latent heat release required to freeze liquid
water to objects for any significant ice storm. Signs of in-situ
wedge being able to form is noted in a lot of the model guidance.
This could certainly be a way for us to "hang on" to even colder
surface temps than many of the models have shown. Dynamic cooling
may also be possible, especially if models showing substantial 925
mb-850mb drying in lead up to storm are accurate. This would allow
us to physically drag some of the colder air aloft down to the
surface, especially in heavier precip.
Finally, getting into central Georgia - initial onset looks like it
may also be snow during morning hours as the initial WAA pushes
through the area as the surface low starts to progress east. The
expectation is that it will be a bit more difficult to hold on to
the cold air here at the surface. A period of sleet or freezing rain
may be possible in some locations before a quick transition to a
cold rain. This would likely lead to limited impacts during the
morning hours. A winter weather advisory may be needed in some
counties that are south of the current winter weather watch to cover
morning impacts, but given high uncertainty in potential impacts,
will hold off on any watch issuance for these areas.
Speaking of the winter weather watch - small southward expansion for
a few counties in eastern Georgia with this update, otherwise no
large changes. The overnight forecast package will be the earliest
we see any upgrades to these, and given onset time, and potential
uncertainties, it is possible this may not occur until the afternoon
tomorrow. Want to emphasize the timing of when impacts may begin in
the current watch area - snow may begin falling right across the
morning commute for many areas, especially to the west. Surface
temps at onset are in the mid to upper 20s and it will have been
quite cold in the lead up to this storm. Soil temps are cool per UGA
mesonet near surface. Put it all together, and snow will likely
begin to stick pretty quickly, especially if we get any decent
snowfall rates. This would likely include roadways. Untreated roads
may become icy and hazardous very quickly. If you can, please
consider staying off the roadways on Friday.
Winter weather looks to come to an end on Friday night into early
Saturday morning. Cold air settles back into the area, and combined
with any potential snowpack, highs on Saturday are only in the 30s
to 40s for most of the area. Saturday night is looking cold.
Widespread teens are expected including into areas even south of I-
20. Areas in central Georgia will drop into the lower 20s. For the
rest of the long term, temperatures are pretty average for this time
of year with not much to talk about (just yet).
Lusk
&&
.AVIATION...
(00Z TAFS)
Issued at 628 PM EST Wed Jan 8 2025
VFR conditions through the forecast with just a few high clouds.
Winds will remain NW 8-12kts with some lingering gusts up to 22kts
at KATL through the evening before decreasing to 6-10kts later
tonight and 5-8kts Thursday.
//ATL Confidence...00Z Update...
High confidence on all elements.
SNELSON
&&
.PRELIMINARY POINT TEMPS/POPS...
Athens 20 45 25 34 / 0 0 0 100
Atlanta 21 42 27 34 / 0 0 10 100
Blairsville 12 39 20 32 / 0 0 0 100
Cartersville 17 42 23 34 / 0 0 10 100
Columbus 22 49 29 42 / 0 0 20 90
Gainesville 20 45 27 33 / 0 0 0 100
Macon 22 47 26 40 / 0 0 10 90
Rome 18 42 24 35 / 0 0 10 100
Peachtree City 20 45 25 36 / 0 0 20 100
Vidalia 24 47 28 48 / 0 0 0 60
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
Winter Storm Watch from Friday morning through Saturday morning
for GAZ001>009-011>016-019>025-027-030>039-041>060.
Cold Weather Advisory from 11 PM this evening to 9 AM EST
Thursday for GAZ041-042-052>054-056-066>073-078>086-089>098-
102>113.
&&
$$
SHORT TERM...SNELSON
LONG TERM....Lusk
AVIATION...SNELSON
Area Forecast Discussion
National Weather Service Fort Worth TX
828 PM CST Wed Jan 8 2025
...New Short Term, Aviation...
.KEY MESSAGES...
- Winter Storm Warning has been expanded to include Montague
County. No other changes were made to the Winter Storm Warning
and Winter Weather Advisory.
- Have increased snow amounts along and north of I-20 based on
latest guidance, but storm total snowfall remains in the 1 to 5
inch range. There is increasing concern of higher totals where
heavier bands set up, and some areas of North Texas could
receive considerably more snow (possibly up to 8 inches). These
heavier snow totals are most likely in our Red River Counties
but could potentially occur in northern parts of the Metroplex.
- Lowered ice amounts slightly based on latest guidance, but still
anticipate up to one tenth of an inch of ice for most of the
forecast area except our far southern counties.
- Main travel impacts are expected to begin Thursday morning and
peak from Thursday afternoon through Friday morning, before
improving some Friday afternoon.
&&
.SHORT TERM... /NEW/
/Tonight through Thursday Night/
Quiet and cold evening across North and Central Texas with
current temperatures in the 30s but dewpoints very low in the
10s/20s. The dry airmass in place will be key to the smorgasbord
of precip types we are anticipating tomorrow with the winter
storm. Latest guidance such as the HRRR indicate precip will
rapidly spread into the forecast area around 10Z and spread over
all of North and Central Texas by 15Z. Forecast soundings show a
warm nose aloft initially along with very dry air in the low
levels, so a mix of freezing rain and sleet is most likely when
precip starts. However, as the airmass saturates and temperatures
fall to the wet bulb temp, precip should transition by late
morning to a cold rain in our southern counties, a mix of sleet
and snow in our central counties, and all snow in our northern
counties. As slightly warmer air advects northward during Thursday
afternoon, the rain/mix/snow line should also shift northward
with the HRRR/NAM suggesting it could move as far as just north
of the Metroplex. By Thursday evening, however, CAA will cause the
transition zone to shift back to the south with rain changing
back to sleet/snow Thursday night before ending by Friday
morning.
Needless to say, the transition zone with the mix of precip types
is the most challenging part of the forecast - with our northern
counties expected to see mostly snow and our southern counties
a cold rain. The exact location of the rain/mix/snow line has
huge implications on which areas will see more ice versus snow.
Latest models continue to show the transition zone shifting around
roughly near the I-20 corridor through the event, giving the
Metroplex a mix of all precip types. However, if the transition
zone does not move as far northward as guidance indicates, the
Metroplex could see considerably more snow (which some guidance
such as the GFS suggest) - and vice versa, if the transition zone
shifts further north, less snow and more rain or ice for the DFW
area. Based on the latest guidance, have upped snow amounts
slightly across our northern half and decreased ice amounts a tad,
but amounts remain in the same range as our previous forecast. It
will be quite fascinating meteorologically to see how this event
eventually pans out.
Shamburger
&&
.LONG TERM... /Issued 246 PM CST Wed Jan 8 2025/
/Friday Morning Onward/
By Friday morning, the majority of the rain and winter precipitation
will be east of the region, with only a scattered chance of snow in
northeast Texas and rain in far southeast Central Texas. Travel
impacts will persist through at least the morning commute as sub-
freezing temperatures and slick spots on roads and bridges will
linger through mid-morning. The base of the upper level trough will
pass overtop the region during the day on Friday, completely ending
precipitation chances by the afternoon. Unfortunately, cloud cover
will be slow to clear out, with mostly cloudy skies lingering
through much of the afternoon. This will inhibit better warming of
air temperatures, and in turn, better melting. With the cloud cover
and snow, temperatures on Friday will be slow to warm above
freezing, with some across North Texas not reaching 32 until closer
to noon. Temperatures will eventually peak in the mid-upper 30s and
will allow for some melting during the afternoon. However, overnight
temperatures will once again bottom out in the upper teens and low
20s along the Red River and north of I-20, where snow amounts are
expected to be greatest, and low-mid 20s elsewhere. This will
promote the refreezing of any water left on roadways. If you venture
out on Saturday morning, take caution when driving as there will be
slick spots on roads, particularly untreated roads and elevated
bridges and overpasses.
Well to our northwest, an open shortwave trough will swing across
the Central Plains over this upcoming weekend, sending a cold front
south. The front will move through the region over the day Sunday,
shifting winds to the north. The better lift associated with the
upper level trough and its attendant surface low will remain well
displaced to our north, as well as any appreciable moisture.
Therefore, the frontal passage will remain dry with only a bit of
cloud cover forecast. One interesting point to note is the continued
surface cyclogenesis across the Texas Panhandle further south along
the front. This feature will enhance surface winds and cold air
advection across the region as the front moves through. Post-frontal
surface high pressure will quickly slide into the region overnight,
keeping winds light. As a response to all of the above, Monday low
temperatures will bottom out from the mid 20s to around 30.
Over the first half of next week, expect a gradual warming trend,
with overnight lows returning into the upper 20s to mid 30s and
afternoon highs into the upper 40s to mid 50s by the end of the
forecast period.
Prater
&&
.AVIATION... /NEW/
/00Z TAFs/
VFR conditions are expected to continue through 11-12Z when MVFR
conditions develop due to a wintry mix of precipitation rapidly
spreading across airports. Main precip types will be SNPL
initially and metroplex airports with FZRA at ACT, with RA mixing
in by Thursday afternoon, before transitioning back to SNPL by
Thursday evening. Cigs/vis will continue to deteriorate to IFR by
late Thursday morning with IFR/LIFR conditions through the rest
of the TAF period. and continuing through the remainder of the TAF
period. Light north winds this evening will become southerly
overnight, then back to easterly and northerly during the day on
Thursday into Thursday evening.
Shamburger
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 29 34 30 36 24 / 10 100 90 5 0
Waco 30 37 32 38 24 / 40 100 100 5 0
Paris 26 33 30 34 18 / 5 90 100 30 0
Denton 26 33 27 35 20 / 10 100 90 5 0
McKinney 26 34 29 35 20 / 10 100 100 20 0
Dallas 29 35 30 37 23 / 10 100 100 10 0
Terrell 27 36 30 36 22 / 5 100 100 20 0
Corsicana 30 37 32 38 27 / 10 100 100 10 0
Temple 29 37 31 38 24 / 40 100 100 5 0
Mineral Wells 27 33 28 35 21 / 40 100 80 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning from 6 AM Thursday to noon CST Friday for
TXZ091>095-102>107-117>123.
Winter Weather Advisory from 6 AM Thursday to noon CST Friday
for TXZ100-101-115-116-129>135-141>148-156-157-159-161.
&&
$$
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
553 PM CST Wed Jan 8 2025
.KEY MESSAGES...
- Light snow will move from west to east across the area
Thursday. Most areas will see less than an inch of snow,
however slick spots are possible.
- Clipper system to bring another chance for snow over the
weekend. Confidence in increasing in the potential for a few
inches of accumulating snow, though timing is still
uncertain.
&&
.DISCUSSION...
Issued at 219 PM CST Wed Jan 8 2025
Sunshine and temperatures in the teens are the theme across most of
south central Minnesota and western Wisconsin this afternoon. The
only difference in sky cover is captured on satellite across central
Minnesota, where an area of stratus is slowly meandering east from
roughly AXN towards STC (and locations to the north). The forecast
will remain dry tonight, with the upper ridge axis positioned
above the Upper Midwest. Water vapor imagery shows ascent
across southern Saskatchewan and northern Montana, associated
with an eastward moving wave that will bring the chance for
light snow on Thursday. High clouds will build ahead of this
feature, which will combine with light southerly flow to prevent
most areas from falling below the double digits tonight.
The aforementioned wave is progged to slide east across the Dakotas
tonight and will send a surface cold front from west to east across
Minnesota/Wisconsin tomorrow. We are expecting a "high PoP/low
QPF" precipitation scenario, where may locations see snowflakes
fly, however poor moisture (a few hundredths) and standard SLR`s
(~12:1) cap snowfall below an inch for most communities. The
highest amounts (Say an inch and a half in isolated settings)
appear to be along and north of I-94 in Minnesota, which will be
tied to better forcing aloft. Nonetheless, forecast soundings
do capture a few hours of deeper saturation in tandem with
sufficient omega forcing to produce light snow across much of
the area. Given high confidence light snow and minor accumulations,
we collaborated with neighboring offices to boost PoPs into the
~60-80% range across west central Minnesota, where hourly
precipitation >0.01" probabilities are the highest per the 12z
HREF. While this will not be a major snowfall, the introduction
of even a half to quarter inch of snow may be enough to produce
slick spots Thursday afternoon & evening. A few snowflakes may
linger amid the northwest flow on Friday morning, before the
southward movement of 1020s Canadian high pressure results in a
brief period of quiet weather Friday afternoon-Saturday
morning.
A potent clipper, originating across northern Alberta, is progged to
dive southeast across the Dakotas Saturday morning. Guidance depicts
the ~1002-1004mb low moving southeast out of the Dakotas into
Minnesota/Wisconsin Saturday evening through Sunday morning.
The compact clipper is set to pivot over southern MN/northern
IA, before lifting to the northeast towards eastern Wisconsin
(towards the region of warm advection). The track of the
clipper will follow the thermal gradient, such that there will
likely be additional support for precipitation from frontogenic
forcing. Latest guidance has trended upward with QPF, with
ensemble means suggesting a wide swath of ~0.1" liquid
precipitation. A variety of individual ensemble members and
deterministic counterparts have trended wetter, with perhaps
upwards of ~0.2" of QPF. That`s plenty of moisture to work with
for this time of year, especially given the expected higher
ratio nature of these clipper events (SLR`s between 15-18:1 per
the latest NBM and conceptually could be higher). For this
reason, confidence is increasing in widespread accumulating snow
over the weekend. We`ll have to fine tune the details over the
coming days, as timing and duration of snowfall remain in flux,
but the large scale pieces are pointing in a more likely direction
for a few inches of snow. For this reason, we collaborated with
neighboring offices to boost QPF through 18z Sunday, to reflect
values closer to the ensemble mean referenced above. Additionally,
we boosted PoPs Saturday night/Sunday morning, so the grids now
feature 40-50% PoPs at all forecast points.
The forecast dries out early next week, following the departing
low. Cold advection across the Upper Midwest will work to drop
temperatures into the single digits for highs Monday/Tuesday,
along with the potential for sub-zero lows. Factor in what may
end up being a fresh layer of snow and these values could end up
even colder as we approach the end of the forecast period.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 545 PM CST Wed Jan 8 2025
Not much going on through Thursday morning. There is a narrow
batch of MVFR stratus over central MN that will skim just north
of MSP and may briefly impact RNH. After that, we`re waiting on
an expected North to South oriented band to move across the area
in the afternoon with a cold front. Timed that snow in with a
blend of the NAMnest and HRRR for now. Snow won`t last more than
3 hours, with a brief 60-90 minute window of IFR snow possible
at each airport. Winds will be southerly ahead of the snow, but
a wind shift will be associated with the snow over to the WNW.
KMSP...a little band of snow is expected to hit the airport
between 19z and 21z. A brief period of IFR vis will be possible
with snow, but this looks to be more of a nuisance type snow,
with accumulations under 0.5"
/OUTLOOK FOR KMSP/
FRI...MVFR early, then VFR. Wind NW 5-10kts.
SAT...VFR. IFR/SN likely overnight. Wind S 5-10kts.
SUN...MVFR/IFR/SN likely in mrng. Wind NW 10-15G25kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&
$$
DISCUSSION...Strus
AVIATION...MPG
Area Forecast Discussion
National Weather Service Portland OR
339 PM PST Wed Jan 8 2025
.SYNOPSIS...High pressure will largely result in dry weather
across the region. The main exception to this will be on Friday
when a front will bring widespread light valley rain and
mountain snow to the region with a few showers lingering over
the higher terrain into the weekend. Another dry spell is expected
early next week, albeit with cooler temperatures, mainly overnight.
&&
.DISCUSSION...Now through Tuesday night...Models and their ensembles
remain in good agreement regarding the synoptic scale pattern over
the next week, suggesting varying degrees of upper level ridging over
the Pacific Northwest aside from Thursday night/Friday when a
transient 500 mb trough and attendant frontal system sweeps inland
from the Pacific. Minimal impacts are expected with this system,
however it will bring widespread valley rain and Cascade snow. Given
the fast-moving nature of this frontal system, not expecting
significant rain amounts in the lowlands or significant snow amounts
in the Cascades. The NBM mean suggests 24-hr rain amounts around
0.25-0.30 inches across the interior lowlands with 0.25-0.4 inches
along the coast and 0.5-0.75 inches along the west slopes of the
coastal mountains and across the Cascade foothills. Not much snow is
expected in the Cascades, generally only an inch or two. Prior to
Friday`s system, expect more dry weather with near normal to slightly
above normal temperatures. In addition, patchy valley fog is possible
in the morning for outlying rural areas Thursday morning.
Light post-frontal showers will continue into the weekend, however
these showers will be mainly orographically driven and confined to
the mountains. Upper level ridging returns early next week with
another period of dry weather, even in the mountains. Easterly winds
will also redevelop during that time in the Columbia River Gorge and
eastern Portland/Vancouver metro, albeit nothing of significance for
this time of year. Wind speeds at this time are not expected to reach
impactful levels. What may be slightly more impactful are colder
temperatures Monday night and Tuesday night; this is when low temps
are forecast to dip into the low to mid 30s. Cannot completely rule
out lows below 30 degrees in outlying rural areas where the NBM is
showing a 50-75% chance. -TK
&&
.AVIATION...VFR conditions prevail across the region this
afternoon with just some scattered high cloud cover drifting
overhead. Expect these VFR CIGs/VIS to persist through the evening
hours. The main concern overnight will be the return of fog to the
interior valleys 07-12z, especially the southern Willamette
Valley due to the ridge of high pressure building overhead leading
to mostly clear skies and light winds. The latest high resolution
guidance like the HRRR and HREF does show a greater areal
coverage of fog come sunrise Thursday than the last few nights. At
least an increase in easterly winds will help to keep KPDX and
KTTD VFR through the period.
PDX AND APPROACHES...VFR conditions are expected through the
period. East winds redevelop this evening however high resolution
guidance depicts more variability in winds right at the terminal
come 10-14z Thursday morning. -Schuldt
&&
.MARINE...Current bouy data this afternoon shows seas have slowly
calmed back below 10 feet with wave heights expected to further
decrease to 5-7 feet at 12-13 seconds overnight. This is due to
the return of relatively benign conditions expected to persist
through Thursday as the ridge of high pressure rebuilds overhead
and winds turn more offshore. It`s worth noting we could see some
localized stronger easterly gusts of 15-20 kt out of gaps in the
coastal terrain.
Conditions deteriorate Thursday night into Friday as another front
moves across the coastal waters accompanied by a decently large
swell. After a brief period of southerly winds Thursday night,
winds will strengthen out of the northwest and become gusty on
Friday in the wake of the front. The Likelihood of Small Craft
wind gusts sit around (70-90%) but the chance for Gales is rather
low, less than 5%. The building westerly swell will also help to
push seas back into the low to mid teens through early Saturday.
Look for winds and seas to trend back down as high pressure builds
back over the region Sunday through early next week. -Schuldt/CB
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory until 1 PM PST this afternoon for PZZ210.
Small Craft Advisory until 10 AM PST this morning for
PZZ251>253-271>273.
&&
$$
www.weather.gov/portland
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Area Forecast Discussion
National Weather Service Springfield MO
550 PM CST Wed Jan 8 2025
.KEY MESSAGES...
- Cold conditions will occur across the area into tonight.
- Snow is likely across the area Thursday evening into Friday.
- Generally dry conditions and closer to normal temperatures for
this time of year in the Saturday through Tuesday time period.
&&
.SHORT TERM /THROUGH FRIDAY/...
Issued at 130 PM CST Wed Jan 8 2025
Synoptic overview and current conditions: Water vapor imagery
and upper level analysis continue to show northwest flow over
the forecast area with a strong cut-off low over the Baja
region. Visible imagery shows a large area of stratocumulus
across the forecast area which is leading to some scattered
flurries. A large area of cold high pressure was centered over
the plains with temperatures here over the Missouri Ozarks and
extreme southeast Kansas still in the teens to mid 20s.
Rest of the afternoon: The stratocu deck will persist in the
afternoon with scattered flurries continuing with no
accumulation expected. Temperatures will likely not get out of
the 20s this afternoon, with the best potential over south
central MO near the AR border.
Tonight: Another cold night is in store as the area of high
pressure drifts overhead. The stratocu should clear out and with
a light wind we should dip back into the single digits to teens.
Thursday: The upper level closed low should begin to open up and
start to eject eastward. A surface low should start to develop
along the Gulf coast of Texas. Upper energy and jet dynamics
should start to move into the area by late in the day with some
light snow developing during the late afternoon in the southwest
portion of the CWA.
Thursday night-Friday snow potential: The surface low will
continue to track along the Gulf coast with the upper wave
tracking east into the plains. Upper energy will continue to
push across the area. RAP showing the potential for some
frontogenetic forcing at 700 and 850 mb across the area with the
potential for some southwest to northeast snow bands. With the
surface low so far to the south, the main snow accumulations
over our area will likely be within these narrow snow bands and
there may be several that set up. Unfortunately, while we can
predict a generalized area where these mesoscale bands may set
up, it is difficult to pinpoint exactly where they might occur.
Outside of these narrow bands, snowfall amounts will be less
than the overall forecast, and within these bands, it may be
slightly higher totals. We will likely be going with a winter
weather advisory from around 5 pm Thursday through 6 pm Friday
to account for the accumulating snow. Generalized snow amounts
over the area will be in the 2 to 4 inch range, however may be
lower outside of the main snow bands and slightly higher within
the bands.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 130 PM CST Wed Jan 8 2025
After this system exits the area, we should continue to see
lower than normal temperatures persist, however they will not be
as bitterly cold as we`ve had the past few days. Lows in the
teens to 20s and highs in the 30s are expected.
An upper level wave Saturday night into Sunday will bring cloud
cover to the area, but the majority of any precipitation should
remain north of the area.
After this wave passes through, temperatures will begin to
moderate to more normal towards the middle to end of next week
with little to no precipitation.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 549 PM CST Wed Jan 8 2025
VFR conditions and light winds will continue through most of
this TAF period. However, snow will move through the region
late Thursday into early Friday, with light to moderate snowfall
and IFR to LIFR conditions expected.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
KS...Winter Weather Advisory from 5 PM Thursday to 6 PM CST Friday
for KSZ073-097-101.
MO...Winter Weather Advisory from 5 PM Thursday to 6 PM CST Friday
for MOZ055>058-066>071-077>083-088>098-101>106.
&&
$$
SHORT TERM...Lindenberg
LONG TERM...Lindenberg
AVIATION...Titus