Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/29/25
Area Forecast Discussion
National Weather Service Amarillo TX
554 PM CST Tue Jan 28 2025
...New AVIATION...
.KEY MESSAGES...
Issued at 242 PM CST Tue Jan 28 2025
- Light precipitation will move in over the Panhandles tonight
through Wednesday night. Light snow may move in across the
northwest which may lead to minor accumulations during this time
frame.
- Warmer and drier conditions are forecast this weekend into early
next week.
&&
.SHORT TERM ...
(This evening through Wednesday night)
Issued at 242 PM CST Tue Jan 28 2025
The latest 28/19z RAP H500 analysis currently has a low pressure
system located over northern Arizona and it is slowly trekking
east today. Out ahead of the system, upper level moisture is
moving north and high clouds are streaming in from south to north
across the Panhandles. These clouds are not very thick so daytime
heating should not be impacted too much and highs will still be in
the 50s area wide this afternoon.
Heading towards tonight, low level moisture will begin to surge
northwards across eastern NM and west TX. The moisture plume
should be associated with weak perturbations rotating around the
H500 low pressure system as it slowly moves towards the High
Plains on Wednesday. The lift provided by the subtle shortwaves
should be enough to kick off some light rain and/or drizzle across
the Panhandles beginning tomorrow morning. Given the lack of mid
level moisture, currently leaning towards light rain showers and
potentially drizzle with this system. Precipitation amounts
continue to go down in the model guidance which is not surprising
given the lack of moisture throughout the entire atmospheric
column. For areas across the northwest, temperatures should be
able to drop to near or just below freezing tomorrow morning and
going into tomorrow night which may allow for some very light
snowfall to accumulate upwards of a half inch to potentially an
inch for locations west and northwest of Dalhart to Boise City. In
addition to the rain/drizzle, fog may linger for much of the day
tomorrow as surface moisture will be prevalent across much of the
CWA. With all of that being said, temperatures will be on the
cooler side tomorrow and have slight lowered NBM highs to better
match other blended model guidance which was all cooler than the
NBM.
With the track of the upper level low moving towards CO/KS late
Wednesday into the early morning hours of Thursday, a dry slot
will kick out most low level moisture (with the exception being at
the surface) and will lead to an end of the light precip. Precip
should end from southwest to northeast beginning Wednesday
evening with most precip out of the CWA by sunrise on Thursday.
Patchy fog may linger through Wednesday night as surface moisture
will remain higher across the entire area.
Muscha
&&
.LONG TERM ...
(Thursday through next Monday)
Issued at 242 PM CST Tue Jan 28 2025
The H500 low pressure system is forecast to be just north of the
forecast area to start off the day on Thursday. With the low
pressure system being to our north, this should keep the
Panhandles in a dry slot, which is shown well by the forecast
H700 theta-e. Sky cover will clear out on Thursday which will aid
in allowing temperatures to rebound back into the mid 40s
northwest to upper 50s southeast. Model soundings indicate mid
level moisture may start increasing late on Thursday, which would
bring in mid to high level clouds over the Panhandles.
Additionally, wrap around moisture to the west of the surface low
may bring in some very light rain/snow showers to portions of the
northern Panhandles. Have opted to leave NBM low end PoPs for
Thursday night into Friday for now, but not very confident that
wrap around precip will occur across the CWA at this time. The
upper level low pressure system should be well off to the east of
the High Plains by sunrise on Friday.
Zonal upper level flow looks to remain across much of the southern
CONUS Friday through early next week. Low level southerly winds
combined with the zonal flow will contribute to bringing in H850
WAA to the region. Just how warm these low level temperatures
become ranges in the latest 28/12z model suite. Some of the warmer
guidance increases H850 temperatures up to 20 to 21 Celsius on
Sunday and Monday. This leads to temperatures well above average
to start February, with highs in the 70s and a few areas may even
get close to the 80 degree mark should these abnormally high
February temperatures verify. Dry conditions are forecast this
weekend through early next week given the aforementioned upper
level pattern.
Muscha
&&
.AVIATION...
(00Z TAFS)
Issued at 550 PM CST Tue Jan 28 2025
VFR conditions expected until about 10-15z. As moisture moves in
from the south categories will drop starting at KAMA and will
follow a few hours later at KDHT and KGUY. Overall with on and off
showers expected IFR conditions seem most likely from 15z-00z, but
will not rule out LIFR conditions as low clouds and possibly fog
could move into the area.
Weber
&&
.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX 32 44 29 53 / 10 80 40 10
Beaver OK 25 46 29 51 / 0 50 80 20
Boise City OK 22 44 22 45 / 0 60 70 30
Borger TX 31 45 32 54 / 0 70 70 20
Boys Ranch TX 28 44 27 52 / 0 60 30 20
Canyon TX 33 44 29 54 / 20 80 20 10
Clarendon TX 36 47 33 57 / 20 80 60 10
Dalhart TX 23 44 24 48 / 0 60 50 30
Guymon OK 24 45 26 48 / 0 60 70 30
Hereford TX 32 45 28 53 / 20 80 20 10
Lipscomb TX 30 46 33 53 / 0 60 80 20
Pampa TX 32 44 32 53 / 0 70 70 20
Shamrock TX 36 48 36 60 / 20 70 80 20
Wellington TX 39 49 38 60 / 30 80 80 10
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...None.
OK...None.
&&
$$
SHORT TERM...05
LONG TERM....05
AVIATION...89
Area Forecast Discussion
National Weather Service Denver/Boulder CO
753 PM MST Tue Jan 28 2025
.KEY MESSAGES...
- Watching next system closely, but growing confidence this is
mainly a light snow event Wednesday night - Thursday noon, with
a focus toward the Palmer Divide and adjacent plains through
east central Colorado.
- Warmer but breezy Friday into the weekend. Lots of uncertainty
with magnitude of warmup with potential for backdoor cold
front(s) Sunday into early next week.
&&
.UPDATE...
Issued at 753 PM MST Tue Jan 28 2025
Clear skies and light winds will prevail through the rest of the
night. This will lead to another cold night in the typical
mountain valley locations where lows of -10 to -20F are expected.
Also nudged temperatures lower in the low lying areas north of
Denver into the lower to mid teens.
Regarding the Wednesday night and Thursday system, the 18Z models
and the few 00Z models in so far haven`t cleared the picture at
all. The 00Z NAM and HRRR show 0.50 to 0.75 (in) of precipitation
for southern and eastern parts of the Denver area. This would
yield 5 to 10 inches of snowfall. The 18Z GFS did take a step
drier, while the 18Z ECMWF held steady with the heavier band of
snow staying over the eastern plains with the Denver area dry. No
changes to this part of the forecast at this time. We will need
to take a good look at all the 00Z model guidance before making
changes.
&&
.SHORT TERM /Through Wednesday/...
Issued at 124 PM MST Tue Jan 28 2025
Only minor changes to the forecast with an almost clear night
ahead. South Park warmed up today, so we`ve backed off a little on
the cold overnight lows there. Not so much in Grand and Jackson
counties where there are still substantial inversions. It should
be at least 10-20 degrees warmer than last night, but that still
means lows of zero to 15 below in the valleys.
During the day Wednesday, the central mountains will be on the
edge of the lift as the next system approaches. Clouds will be
spreading in, but it doesn`t look like there`s much change of
appreciable snow until late in the day or more likely the evening.
We slowed the advent of the clouds, and focused the PoPs more in
this area and less further north in the afternoon.
&&
.LONG TERM /Wednesday night through Tuesday/...
Issued at 245 PM MST Tue Jan 28 2025
The main concern continues to revolve around the upper level low
that moves slowly east/northeast across northern New Mexico
Wednesday night, and then into southwest Kansas Thursday. There
are small differences in each of the ensemble datasets with regard
to the track, with the GEFS/SREF/NAM being farther north
(southeast Colorado), the EPS middle of the road (CO/KS/OK tri
state area), and the CMCE just a touch farther south but trending
toward the EPS solution.
While this track is favorable for snow across the forecast area,
this particular storm has limiting factors such as; 1) lack of
lee side cyclogenesis and thus limited upslope forcing, 2) a very
dry airmass to start, 3) some dry slots aloft during the event,
and 4) lack of a deep DGZ. Meanwhile, favorable attributes
include 1) the track resulting in persistent QG lift, 2) some
influx of gulf moisture, and 3) modest mid level lapse rates
of 6-7 C/km.
Due to the continued uncertainty, we`ll still rely on the vast
array of ensemble data and average close to the mean of all
systems. This puts locations such as the Palmer Divide and east
central plains of Colorado through Limon and Lincoln County in the
most favored locations for accumulating snowfall, with a much
lower threat of accumulating snow from Boulder and the northwest
Denver suburbs toward Fort Collins and Greeley. Those latest
locations listed would also be more prone to downslope from
shallow northwest winds off the foothills and Cheyenne Ridge, a
result of the lack of significant cyclogenesis. Thus, we feel
pretty confident that those area would see little if any
accumulation, and the only way that would change is if this storm
suddenly trends to, or north of, the GEFS/HREF tracks. If it did,
then more upslope would occur into the northern foothills, but
only about a 20% chance of that. The opposite could hold true over
the southern/eastern sections of metro Denver into the Palmer
Divide, where deep NNW flow supports upslope flow on the back end
of this cyclone. We saw a similar flow pattern on January 9th
which brought more accumulation than anticipated over the far
southeastern suburbs into Parker and Elizabeth, so if the storm
did get sufficient moisture wrapped into it without dry slots then
more snow would be possible. This appears to be a pretty low
confidence though since the system is relatively moisture starved
early on, and there`s only about a 6 hour period late Wednesday
night - Thursday morning when heavier snow would be possible. Only
a few of the ensemble members (10-20%) showed possibility of a
4-6" snow on the Palmer Divide. However, there`s smoothing in the
courser ensemble runs so our deterministic forecast will be closer
to (not at) that higher end for now. Again, the opposite holds
true from about Downtown Denver northward where we`ve lowered
ensemble output in the deterministic forecast (0-1").
For Thursday afternoon, we`ll see the snow taper off and end from
northwest to southeast, with some sunshine returning by late in
the day. Temperatures will be a little chilly to start, but
there`s essentially no cold air advection with this cutoff low so
don`t look for much cooling overall.
The quick departure and lack of cold advection in this system`s
wake will support a further warmup for Friday, and this warming
trend will likely (70% confidence) continue through the weekend.
However, there is a real threat of a backdoor cold front sneaking
across the plains by Sunday and especially by Monday. The forecast
areas will be a real battleground between springlike warmth and
winter`s cold. This can be seen in the 25th-75th percentiles of
the EPS output ranging anywhere from 38-65 for Monday, while the
far extremes show potential anywhere from highs in the mid teens
to mid 70s! GEFS probabilities are not quite as scary and shoot
closer to the middle of that range. Where the cool air does not
surge in, we`ll see breezy to potentially windy conditions at
times. Those windy conditions favor locations in and immediately
next to the Front Range Mountains and Foothills. Mostly dry
weather should prevail through this period, although the northern
mountains may reside on the far southern extent of a Pacific
moisture plume, just enough to keep some chance of light snow
showers in the forecast there.
&&
.AVIATION /00Z TAFS through 00Z Thursday/...
Issued at 439 PM MST Tue Jan 28 2025
VFR and light winds to prevail under clear skies through tonight
and Wednesday morning. Clouds will increase Wednesday afternoon,
after 21Z, with ceilings expected to fall to around or below 6000
feet around 01Z Thursday. Best chance for snow with this next
system will be 06Z-18Z Thursday.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Meier
SHORT TERM...Gimmestad
LONG TERM...Barjenbruch
AVIATION...Meier
Forecast Discussion at weather.gov/mqt.
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...Winter Weather Advisory until midnight CST tonight for MNZ012-
021.
WI...None.
MARINE...Gale Warning until 2 AM CST Wednesday for LSZ140>148.
Gale Warning until 5 AM CST Wednesday for LSZ150.
&&
$$
DISCUSSION...BJH
AVIATION...Britt
MARINE...BJH