Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/09/23
Area Forecast Discussion
National Weather Service Denver/Boulder CO
820 PM MST Sun Jan 8 2023
.UPDATE...
Issued at 820 PM MST Sun Jan 8 2023
No significant updates needed for tonight`s forecast. There is
still a little mountain wave activity going on per latest GOES-E
satellite water vapor imagery. The reflection at the surface
extends from the Boulder-JeffCo line east to DIA, but west winds
are 15-25 kts at this time and shouldn`t increase. Winds across
the north metro area should weaken in the next 2 hours as the
inversion above ridgetop weakens. Modest increases in winds were
made to account for the last bit of mountain wave activity impacts
the surface. Otherwise, the forecast for most of the area was
left intact. One final update was to PoPs in the mountains. A
check of all the webcams and AWOS sites in the highest elevations
(Rabbit Ears, Dakota Hill, Berthoud Pass, Copper Mountain), shows
a dry airmass with no snow noted anywhere yet. With it being a
little drier upstream than we originally had in the forecast, just
dropped PoPs across the highest ridges down 20 percent or so to
the lowest of slight chance categories through the morning hours.
We do not expect any impacts from any light snow that falls
tonight.
&&
.SHORT TERM...(This evening through Monday)
Issued at 255 PM MST Sun Jan 8 2023
Weak ridging in the west-southwest flow aloft will prevail over
Colorado today and tonight. Water vapor satellite imagery showing
and a weakening wave over the Great Basin. This wave continues to
weaken as it lifts north of Colorado. Expect this to increase cloud
cover tonight and bring a few light snow showers to the northern
mountains. A few snow showers could linger into Monday morning,
otherwise dry conditions are expected for Monday. Airmass
continues to slowly warm with highs in the 50s across the Front
Range. HRRR shows an inversion remaining over the plains where
highs will be cooler, upper 30s to 40s.
.LONG TERM...(Monday night through Sunday)
Issued at 255 PM MST Sun Jan 8 2023
No major impacts expected for the period. Snow expected in the high
country through Weds evening with a chance for snow showers for
portions of the plains Wednesday. High winds are possible Tues
for the high mountains, mainly in the morning. With the exception
of Weds, temperatures stay above normal for the period.
Mon evening, the flat upper level ridge weakens and pushes to the
east as an approaching trough advects in lower heights. Ensembles
show WSW flow aloft advecting above normal moisture into the
region that evening. Model cross sections show a similar story
with moisture depth increasing over the high country. Although
lacking in large scale ascent, light orographic snow showers
develop in the high country overnight continuing Tues. Flow aloft
will be enhanced as well with cross-barrier flow increasing to
40-50 kts by Tues AM. Initially, this indicates potential for
mountain wave/high winds for the front range mountains. High-
resolution ens guidance follows suit with gusts potentially up to
65 mph in spots. One thing working against this is the lack of
defined stable layer close to ridge top as well as moisture to the
west in the high country. Still increased the winds from the NBM
to reflect this potential and settled on gusts up to 50-60 mph for
the high peaks Tues morning for now. The lower elevations will
remain dry Tues with highs above normal in the 40s to near 50.
Areas of the east plains are more likely to stick in the 40s,
especially if any snowpack remains about.
A quick moving trough moves through overnight into Weds. There is
general agreement shown by ensembles in regards to the position of
the low provides as it moves through SE CO by the afternoon. The
approaching system will result in QG ascent ahead of it. Lapse rates
in those areas improve into the early evening, increasing snow
chances in the high country overnight into Weds. Most model
guidance shows potential for snow showers to develop over the
plains Tues morning. Model guidance shows hints of a easterly
surge across the eastern plains in the late afternoon/early
evening period as the surface low moves across SE CO. If this
"surge" gets far enough west, a brief period of upslope component
may enhance the showers before drier air works in that evening.
Showers will taper off by throughout the evening period. For
totals, 2-6 inches for most of the mountains with locally higher
amounts up to a foot for the Park Range across the entire event.
The plains will see an inch or two at most.
An upper level ridge builds in Thurs continuing through much of
the weekend. This will bring a drying and warming trend to the
region.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 443 PM MST Sun Jan 8 2023
VFR and light winds through Monday. Light SE winds should go more
SSW at DEN and APA after 7 PM, and remain around 8-12 kts. BJC
should be west more or less. Winds from late morning through mid
afternoon should be southerly at DEN and APA, around 10 kts. West
winds may pick up a bit at BJC 10-15 kts during the afternoon. By
evening winds should be light and variable before returning to SSW
at DEN and APA, SW at BJC.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Schlatter
SHORT TERM...Meier
LONG TERM...Mensch
AVIATION...Schlatter
Area Forecast Discussion
National Weather Service Quad Cities IA IL
859 PM CST Sun Jan 8 2023
.UPDATE...
Issued at 850 PM CST Sun Jan 8 2023
Will continue to monitor fog potential tonight. What is different
from last night is we`ve got more wind just off the surface and
from a westerly /drier/ direction. While warm advection will be
increasing overnight, this coupled with a developing light
southerly surface wind may help to limit dense fog and keep it
more shallow in vertical extent /ground fog/. If dense fog were
to develop it would be most favored over far northeast Iowa and
northwest Illinois, which has also been hinted at by the HRRR for
the past several runs.
Temps continue to plunge with the ideal radiational cooling setup
this evening, and have lowered Mins in most areas by 1-3 degrees.,
We may see readings level off overnight in the developing WAA
regime, and possibly even come up a bit in western areas within
the better strengthening southerly wind.
&&
.SYNOPSIS...
Issued at 207 PM CST Sun Jan 8 2023
Drier air will continue to filter in from the southwest, which has
helped lead to dissipating cloud cover. Areas over southeast Iowa,
far northeast Missouri, and extreme west-central Illinois are seeing
abundant sunshine this afternoon, which will only expand to the
northeast. Overcast skies are hanging tough over the northeastern
half of the region, but, as mentioned, these clouds should continue
to erode. With that being said, temperatures have ranged between the
lower to middle 20s to the north, with lower to middle 30s to the
south.
&&
.SHORT TERM...(This Evening through Monday)
Issued at 207 PM CST Sun Jan 8 2023
Key Messages...
1) Dry conditions will prevail through Monday afternoon and into
at least the middle of the week, with a warming trend Monday
2) Patchy fog expected tonight, mainly over northeastern Iowa
As a mid-level shortwave continues to translate eastward this
afternoon, drier air will continue to filter in from the west, which
is bringing some sunshine across our southwestern areas. This
clearing trend should continue into the evening hours. An area of
high pressure will settle just south of our region, keeping dry
conditions in place tonight. However, with light winds, and the
clearing skies, some patchy fog will be possible tonight. Models
aren`t too bullish on visibility reductions, so dense fog potential
should remain limited.
Warmer temperatures will filter into the area Monday, thanks to
southerly return flow on the western side of the high pressure ridge
axis as it shifts eastward, resulting in highs warming to the upper
30s north to the middle 40s south.
.LONG TERM...(Monday Night through Sunday)
Issued at 207 PM CST Sun Jan 8 2023
[Key Messages]
1) Quiet weather from early through mid next week
2) Evolution for Thursday system is trending more south of the area
3) Temperatures hold above early January normals
[Discussion]
Monday Night through Wednesday Night...
Quiet weather is expected for this period with zonal flow aloft in
place over the Plains and Midwest. In the lower levels, flow will
generally be out of the south, promoting a period of well above
normal temperatures. Look for highs Tuesday and Wednesday to climb
into the upper 30s to low 40s, with lows only falling into the mid
20s to low 30s. This will be occurring despite partly to mostly
cloudy skies favored with a weak passing disturbance and increasing
moisture aloft from the southerly flow.
Thursday...
Robust shortwave trough will arrive on the California coast, and
will undergo strengthening as it crosses over the Rockies and
traverses the Plains. Low pressure will develop in response to
this across the south central Plains, and is forecast to track
into the mid-Mississippi River and Ohio River Valley Thursday. As
this system tracks east, it will phase with another shortwave over
the Great Lakes with a track into the northeastern U.S. by
Thursday night.
Model guidance across the board has been consistent in a southward
trend of this system, likely due to a delay in phasing the
shortwaves over the Ohio River Valley vs. the Midwest. Ultimately,
this favors precipitation to be more focused into Missouri and
central Illinois vs. into Iowa and northwest Illinois, leaving
much of us completely dry. However, this is still low confidence
given how far out this is and potential for a change in the
phasing, so have kept chance POPs in the forecast for now during
the day Thursday. Stay tuned.
Friday into the Weekend...
A dry end to the week is favored with high pressure moving into the
Midwest. Despite that, temperatures look to remain slightly above
normal.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 625 PM CST Sun Jan 8 2023
Clearing of stratus and IFR/LIFR ceilings at DBQ will occur over
the next hour or so. 00z DVN RAOB shows a very dry profile with
deep WNW winds, thereby decreasing the threat for much in the way
of fog at most of the terminals aside from patchy MVFR visibilities.
However, KDBQ will need to be watched for more prevalent fog and
lower visibilities of IFR to possibly LIFR/VLIFR in the wake of
departing stratus in the reservoir of small temp/dew point
depressions.
The departing ridge late tonight and Monday morning will be
accompanied by a gradual strengthening of southerly flow, which
will foster a return of widespread VFR conditions. Southerly
winds should become sustained at around 10-15 kts by mid morning
Monday.
&&
.CLIMATE...
Issued at 236 AM CST Sat Jan 7 2023
Week 2: The Climate Prediction Center has a very high likelihood
(85% or greater) of above normal temperatures across the Upper
Mississippi Valley region for the January 14th-20th timeframe.
Above normal precipitation is slightly favored. This would mean
several days with highs well above freezing, occurring right when
we normally see the coldest temperatures of the year.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...McClure
SYNOPSIS...Schultz
SHORT TERM...Schultz
LONG TERM...Speck
AVIATION...McClure
CLIMATE...Speck
Area Forecast Discussion
National Weather Service Grand Forks ND
625 PM CST Sun Jan 8 2023
.UPDATE...
Issued at 614 PM CST Sun Jan 8 2023
Question tonight is fog development. Very uncertain, which is not
unusual for fog development. Skies clear and there is a light
south or southwest wind tonight. Some high clouds moving thru the
RRV early this evening but overall a generally clear sky. There
was no snow melt and hasnt been for a long time to add moisture to
the lower levels. There are some higher dew pts in SW MN (20-23)
near the Minnesota River in a small area around Canby/Madison MN
south of our forecast area. This possibly could advect northeast
some tonight and bring increased low level moisture into WC MN.
MAV and and a few other short terms indicate a bit higher chances
for fog in WC MN than other areas. HRRR and NBM development
blotches of low vsbys pretty much all over. Fcst grids for fog
with patchy and areas look good and no changes.
&&
.SHORT TERM...(This evening through Monday night)
Issued at 329 PM CST Sun Jan 8 2023
Fog, yet again, will be the primary concern for the short term
period and where dense fog develops the potential for freezing fog
and flurries.
A weak mid level wave passes through the region overnight and weak
surface troughing also transitions through our area. There isn`t
enough moisture aloft or forcing to result in measurable
precipitation, but in the BL or near the surface inversion southerly
and southeasterly flow may lead to weak WAA/weak moisture advection
and when combined with radiational cooling additional fog will
likely develop. There won`t be high predictability on locations of
dense fog/freezing fog, however the signal is strong for at least
fog development once again tonight into Monday morning. The surface
layer isn`t going to see a strong shift in flow, so stratus/fog may
linger or redevelop once again Monday into Monday night.
As with previous days, where low level saturation or stratus is high
enough we could see flurries and localized dusting of snowfall
(again low confidence in location/occurrence. Temperatures will (as
usual) be impacted by clouds/fog. Where cloud cover/fog persists lows
will remain in the teens, where there is more persistent clearing
they may drop to near zero. During the daytime if there is less
clearing then they will hold in the low teens, but with more
clearing/sun they should reach the 20s (especially in forested
areas).
.LONG TERM...(Tuesday through Sunday)
Issued at 329 PM CST Sun Jan 8 2023
Little to no impacts are expected during the long term as a
flattened ridge remains over the region. Temperatures remain above
average early to middle portion of the week. There are slight
chances for weak waves to shift across Canada and bring chances for
flurries or a light snow shower at times over the course of the next
several days. One chance appears Tuesday night into Wednesday.
Chances are slim, but still possible (20%) for areas east of the Red
River Valley. Little to no accumulation is expected. The cold front
associated with the weak system helps bring temperatures to seasonal
averages end of the week, but guidance continues to depict continued
warm air coming from the south near the end of the long term.
Temperatures have the chance to reach the lower 30s for portions MN,
but this is all dependent on the current snowpack. We have a large
dense snowpack across the area that will help to keep temperatures
cooler near the surface. None the less temperatures will be well
above average to end the work week and begin the weekend. The cooler
temperatures near the surface and warmer air aloft bring the
possibility for patchy fog due to the inversion aloft. This is only
a possibility at this time as guidance is not in great agreement on
fog development outside of the short term.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 614 PM CST Sun Jan 8 2023
Higher than usual uncertainity in regards to fog development
across the area overnight into Mon AM. We are starting the evening
off with good vsby unlike past days. There will be a light south
or southwest wind but also pockets of calm. Low level moisture
from snow melt is lacking so fog formation may be tied more toward
ground fog at first and thus making it very localized/spotty in
coverage at first. How widespread it may get late tonight/Mon AM
is highly uncertain. Thus TAF forecasts out show some fog
development after 06z but what values for vsby in there as the
forecast is low confidence.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...Riddle
SHORT TERM...DJR
LONG TERM...Spender
AVIATION...JR
Area Forecast Discussion
National Weather Service Grand Junction CO
430 PM MST Sun Jan 8 2023
.SHORT TERM...(Tonight through Monday night)
Issued at 312 PM MST Sun Jan 8 2023
Satellite imagery shows widespread high level clouds moving east
as a shortwave moving through the flow nudges the northern portion
of the CWA this evening and overnight. Due to minimal lift, this
could lead to some very light (a few hundredths of an inch) QPF
across northern portions of the forecast area as it passes through
our region. By Monday evening / overnight, expect precipitation
to spread into the area and become fairly widespread across
eastern Utah and western Colorado by midnight as another larger
wave in the flow approaches. Although, the low valleys (below
around 5-6K feet) are likely to see rainfall initially as the
system begins. Even in the high country, snow to liquid ratios
will likely struggle to climb to or above 10 to 1 through the
first half of the event. At any rate, get used to more time away
from the sun with fairly persistent clouds behind the shortwave
tonight and leading up to the real disturbance approaching
tomorrow. See the long term for more details about accumulations
(likely near advisory thresholds) by the time this system wraps
up.
Temperatures will climb slightly warmer tomorrow thanks to the
WAA. Above normal (5-15+ degrees) warmth will continue tonight
thanks to persistent thick cloud cover with even warmer (15-20+
degrees) conditions Monday night CWA-wide.
.LONG TERM...(Tuesday through Sunday)
Issued at 312 PM MST Sun Jan 8 2023
Little change to current thinking with regards to the long term
period. A relatively weak short wave trough will be moving across
the CWA Tuesday morning and will bring precip to the region
through Tuesday evening. Previous runs kept QPF and snow amounts
in the sub- advisory level but this latest run has bumped up snow
amounts enough where some low-end highlights might be warranted.
The NAMNest and HRRR are the likely culprits for this increase in
precip. Later shifts will need to see how the models resolve
themselves and if these amounts stay consistent or fluctuate. Of
note, QG forcing is rather light with this trough though an upper
level jet streak of around 90kts will be moving overhead. The left
exit region of said jet will allow for some divergence aloft and
thus, some large scale ascent is likely. Still a few moving parts
with this little system and confidence just not there yet to issue
any winter weather products. Areas to watch would be the Park and
Gore Ranges, Flat Tops, and to a lesser extent the Grand Mesa and
other central mountains. Latest forecast snowfall amounts look to
be in the 4 to 8 range for said locations.
A lull will occur Tuesday evening until a more robust, stand-up
front moves across the area Wednesday morning. Important to
mention that all this precip will be the remnants of Atmospheric
Rivers...yes, plural...that have consistently been transporting
anomalously high amounts of moisture to the West Coast. This next
push of moisture will favor southern portions of the forecast area
as the best upper level support moves through that area. Current
thinking brings snowfall amounts from early Wednesday morning
through Thursday morning of about 4 to 8 inches to the San Juans
and somewhat lesser amounts for the northern/central mountains and
Uncompahgre Plateau.
Height rises then kick in during the day Thursday as a high
amplitude ridge axis sets up across the West. Another AR will be
bringing precip to the West Coast but the location of the ridge
axis will keep any precip in that same general location. Our CWA
will remain dry as the ridge gets nudged eastward Friday and
Saturday. Ample moisture will remain aloft, however, so we can
expect some high clouds for the weekend. Even with those clouds,
highs will generally run just at or a few degrees above
climatological normals.
Looking further ahead, looks fairly active as disturbances move
through with plenty of moisture. Not a bad start to 2023, all
things considered.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 430 PM MST Sun Jan 8 2023
Scattered to broken mid and high level clouds with bases around
10K feet will continue to stream across eastern Utah and western
Colorado through tonight and into Monday. Some light snow may
break out across the northern Colorado mountains from these
clouds, but this is highly unlikely to affect TAF sites.
Otherwise, we continue to monitor KVEL where fog and low clouds
remain concerns. Visibility has improved this afternoon, but
ceilings continue to hover around LIFR/IFR. Ceilings should not
change much through the TAF period. Visibility on the other hand
likely drops to IFR overnight... with LIFR not ruled out.
Elsewhere, expect VFR conditions to persist for the next 24 hours
with light, terrain driven winds.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&
$$
SHORT TERM...SS
LONG TERM...TGR
AVIATION...MDM
Area Forecast Discussion
National Weather Service Lincoln IL
734 PM CST Sun Jan 8 2023
.SYNOPSIS...
Issued at 304 PM CST Sun Jan 8 2023
Mild and dry weather will prevail across central Illinois for the
next few days, with high temperatures in the lower to middle 40s
on Monday climbing into the upper 40s and lower 50s by Wednesday.
The next chance for precipitation will hold off until late
Wednesday night into Thursday.
&&
.UPDATE...
Issued at 734 PM CST Sun Jan 8 2023
Clearing line has pushed across most of the northern CWA, while
some redevelopment has been taking place around Springfield and
Lincoln lately. Evening balloon sounding from our office shows the
atmosphere has scoured out nicely. RAP 925 mb humidity analysis,
which is closest to the cloud heights which are around 1000-1500
feet, shows the clouds lingering near the Indiana border through
about midnight, and the HRRR cloud heights suggest some
redevelopment after midnight near and east of I-57. This is
somewhat of a shift from HRRR runs of a few hours ago which had
the redevelopment much further west. However, the latest NBM
ceiling probabilities still have 30-40% chances of mostly cloudy
conditions as far west as I-55 by 3 am. Have been a little
hesitant on putting a wholesale clearing trend in the evening
forecast update, but have backed down some from earlier forecasts
and kept partly cloudy skies from I-55 west overnight.
With the clearing over the western CWA, temperatures are only a
couple degrees above the forecast lows. However, with winds
starting to come around to the southwest as the ridge axis slides
into eastern Illinois, temperatures should level out soon and stay
fairly steady overnight.
&&
.SHORT TERM...(This evening through Monday)
ISSUED AT 304 PM CST Sun Jan 8 2023
A very light rain/snow mix lingers along the Indiana border this
afternoon: however, the precipitation will come to an end within
the next 1 to 2 hours. Synoptic subsidence behind the departing
short-wave trough responsible for the precip earlier today has led
to clearing across southern Iowa/northern Missouri...with 20z/2pm
satellite imagery showing the clearing now punching into western
Illinois. The big question is how quickly the clearing line will
advance eastward across the KILX CWA. Several synoptic models
suggest skies will become partly to mostly clear as far east as
I-57 by sunset, while other mesoscale models such as the RAP/HRRR
feature a much slower clearing trend. Despite steady eastward
progress of clearing on visible satellite imagery, think slower is
the way to go. Once the sun goes down, am expecting the clearing
line to come to a halt as low clouds re-develop along its leading
edge as per the RAP/HRRR. As a result, think skies will be partly
cloudy across the Illinois River Valley tonight...with mostly
cloudy conditions persisting further east. Lows will drop into the
middle 20s. Clouds will thin/dissipate on Tuesday, with partly to
mostly sunny skies expected everywhere by afternoon. High
temperatures will rise into the lower to middle 40s.
&&
.LONG TERM...(Monday night through Sunday)
ISSUED AT 304 PM CST Sun Jan 8 2023
Warm and dry weather will be the rule for both Tuesday and
Wednesday. Highs will be well into the 40s on Tuesday, then will
reach the upper 40s and lower 50s by Wednesday.
Main weather story in the extended continues to be a storm system
expected to impact the region late Wednesday night into Thursday.
The short-wave trough in question is still well off the
California coast, so has not yet been adequately sampled by
surface/upper air data networks. As such, its evolution and the
exact track of its associated surface low are still somewhat in
question. 12z Jan 8 models have all trended further south with the
low track...with consensus now taking the low between I-70 and
the Ohio River during the day Thursday. This particular trajectory
would allow cooler air to settle southward and introduce some
precip type challenges across the W/NW CWA. Still think enough
warm air will be present to produce mainly a rain event across the
area:however, confidence is growing that rain will mix with
and/or change to snow Thursday afternoon/evening before ending. Do
not think this will be a major snow event by any means, but will
need to keep an eye on the low track and thermal field as minor
snow accumulations north of the I-70 corridor are not out of the
question. Once the low departs, a return to seasonable temperatures
in the 30s is expected for Friday and Saturday before readings
once again climb back into the 40s by next Sunday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 520 PM CST Sun Jan 8 2023
Main TAF concern will be with the eastward progression of the
clearing line in central Illinois. 23Z satellite imagery shows
areas from KPIA-KDEC west are clear to partly cloudy, however
ensemble guidance suggests potential for that area to fill in
again for a time tonight. Cloud heights remain MVFR at this time
but have some potential to dip below 1,000 feet in eastern
Illinois. A more wholesale improvement to VFR conditions is more
likely to begin late morning, but may take much of the day to
spread east to KCMI.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Geelhart
SYNOPSIS...Barnes
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Geelhart
Area Forecast Discussion
National Weather Service Memphis TN
816 PM CST Sun Jan 8 2023
...New UPDATE...
.UPDATE...
Issued at 802 PM CST Sun Jan 8 2023
Current temperatures across the Mid-South are in the upper 30s to
mid 40s, with gradually clearing skies. Temperatures tonight are
expected to drop to near freezing. In addition, light winds and
clear skies could aid in patchy fog development across the region.
As such, freezing fog could develop in regions of extreme
northeast Arkansas and the Missouri Bootheel as temperatures drop
overnight. Otherwise, the forecast remains on track and does not
need additional updates at this time.
ANS
&&
.SYNOPSIS...
Dry weather and clearing skies will prevail for the rest of the
day. Dense fog is possible across much of the Mid-South overnight,
with a possibility of freezing fog in extreme northeast AR. A
more potent system will move into the region late Wednesday night
into Thursday with more showers and thunderstorms and possibly a
few strong to severe storms. Near normal temperatures will
gradually warm to above normal by midweek followed by cooler and
drier weather for Friday and Saturday.
&&
.DISCUSSION...
(This evening through next Saturday)
Issued at 339 PM CST Sun Jan 8 2023
Skies are gradually clearing from west to east this afternoon as a
cold front exits the region into central Mississippi and Alabama.
Though we should remain dry, the combination of lingering moisture
and light winds could lead to fog development overnight. Dewpoint
depressions across the area only look to be about 1 or 2 degrees
through early tomorrow morning around sunrise. Temperatures in
extreme northeastern AR and the MO Bootheel may get down to freezing
while this fog develops overnight, thus leading to a chance for
freezing fog. CAMs don`t quite have a good enough handle on the
intensity or spatial distribution for a Dense Fog Advisory quite
yet, but for now will just continue to mention dense fog in the HWO
with a chance of freezing fog.
We`re looking at a very pleasant and mild next few days as high
pressure builds in. By tomorrow afternoon, a 1026 mb surface high
should be sitting directly over the Mid-South, leading to mostly clear
skies with mild temperatures near normal in the 50s. As the week
progresses, upper level ridging will build in, further reinforcing
a warming trend and nudging temperatures above normal by midweek.
An occluded low pressure system with an associated cold front
looks to approach Wednesday evening, increasing PoPs to the 20-30%
range overnight into Thursday morning. The bulk of the precip
should arrive during the day Thursday, quickly exiting by midnight
that same night.
Due to the occluded nature of the Thursday system, the dynamics do
not look particularly supportive of severe weather. However, GEPS
ensembles do show probabilities of CAPE >= 500 J/kg around 30% in
north Mississippi in a simultaneously well-sheared environment, so
it`s worthy of being denoted as an area to watch in the coming days.
The more supportive environment for severe weather looks to be
farther south along the Gulf Coast in the open warm sector, but we
could certainly see some stronger thunderstorms as the cold front
moves through the Mid-South.
The rest of next week into the weekend looks cool and dry as high
pressure builds back in. Expect afternoon high temperatures to
return to near normal around 50 degrees with overnight lows near
freezing. Our next shot at a chance of rain arrives early next
week as another low pressure system approaches from the Plains.
CAD
&&
.AVIATION...
(00Z TAFS)
Issued at 545 PM CST Sun Jan 8 2023
Primary concern is patchy fog after 09Z, in the wake of exiting
MVFR cloud deck, and with a surface pressure ridge center expected
along the MS River. Earlier HRRR runs had only depicted fog over
northeast AR, but the 22Z HRRR run was likely correctly depicting
fog potential in and around MKL and TUP. Given the almost purely
radiative formation of the fog, MEM sub-VFR visibility potential
appears limited.
By 15Z, light winds and VFR will prevail areawide.
PWB
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
PUBLIC FORECAST...CAD
AVIATION...PWB
Area Forecast Discussion
National Weather Service Pendleton OR
248 PM PST Sun Jan 8 2023
.SHORT TERM...Tonight through Tuesday...A shortwave trough now
traversing central OR continues to push light rain and mountain
snow bands across the far northeast Oregon and eastern WA this
afternoon. With the frontal boundary now well north of the
forecast area, winds along the Blue Mountain foothills as well as
in the Grande Ronde valley have finally weakened below advisory
criteria, though occasional gusty conditions along Cabbage Hill
in OR are still occurring. Tonight, the shortwave trough will
continue to push north across the PacNW and exit the area late
this evening. As the axis moves overhead, expect precip chances to
diminish greatly, though some light snow will still be possible
in the interior northern Blues and along the Cascade Crests.
Behind the shortwave axis, a quick moving transient ridge will
enter the area, resulting in a brief reprieve from snow/rain and
from breezy conditions.
Monday, the transient ridge will quickly be kicked north and east
by a shortwave trough rounding a deepening parent low in the
eastern Pacific. This coupled with a surface low pushing another
front across the PacNW will result in widespread rain showers and
mountain snow spreading southwest to northeast across the
forecast area throughout the day. This system will be a bit more
robust compared today, as a healthier moisture plume aloft and
stronger front at the surface will be present. Up to a tenth of an
inch of rain will be possible across portions of the Basin into
central OR, while snow amounts will range from 1 to 4 inches in
the mountains. Light snow up to a half inch and few hundreths of
an inch of ice accumulations will also be possible in the Kittitas
valley and along the I-82 corridor, though impacts from the ice
will be very low. Turning our attention over the foothills of the
Blues, the accompanying frontal passage tomorrow will result in
tightening pressure gradients across the mountains. Expect breezy
to gusty downsloping winds along the Blue Mountain foothills as
well as through the Grande Ronde valley in the morning through the
afternoon. The strongest winds will once again be around the
immediate foothills and western/northern slopes of the Blues in
OR, with strong winds especially impacting I-84 on Cabbage Hill,
Highway 395, and Highway 11. By Monday evening, the shortwave
trough and frontal boundary will exit into ID, with precip
tapering off and winds becoming light.
Tuesday, model guidance wants to build a ridge along the ID/OR/WA
border which would result in at least dry and benign conditions in
the morning. However, the parent low in the eastern Pacific will
push into the west coast and encounter a split flow due to the
building ridge. The main shortwave energy and moisture will mostly
dive south of the forecast area, however some rap around bands of
light rain (central OR) and mountain snow will push into the
southern periphery of the forecast area. That said, model guidance
only wants to bring in a trace to a couple hundreths of inch of
light rain and only a couple tenths of an inch of snow
accumulations as far north as Horse Heaven Hills in WA. Otherwise,
downsloping winds will redevelop along the base of the Blues
Tuesday, but are anticipated to be only locally breezy and not as
strong as today/tomorrow. Lawhorn/82
.LONG TERM...Wednesday through Sunday...Ensemble mean 500 mb heights
suggest reasonable to excellent agreement regarding the longwave
pattern during the extended period. While the ensemble mean smooths
details in the pattern, the general idea is a weak shortwave trough
affecting the Pacific Northwest Wednesday morning with upper-level
ridging building over the Intermountain West and Inland Northwest
for Thursday before another trough returns for the weekend. Primary
impacts currently look to be focused on the Wednesday and Thursday
timeframe with south-southwesterly flow aloft, mountain snow of 4-6"
in the Washington Cascades, and breezy to windy conditions for the
Blue Mountain foothills and Grande Ronde Valley.
Diving into ensemble clusters reveals some slight differences in the
longitudinal placement of the closed upper-level low for Wednesday
and Thursday; this difference in placement will modulate how much
precipitation the forecast area receives with a more eastward
placement yielding more precipitation for eastern Oregon and
Washington. Confidence is high in precipitation for the Washington
Cascades and their eastern slopes with a signal in the ECMWF
ensemble for climatologically unusual precipitation extending into
the Yakima and Kittitas Valleys. Impacts are not expected
to be anything above minor at this time.
Still focused on Wednesday night and Thursday, the ECMWF EFI shows a
strong signal for climatologically abnormal winds for portions of
central Oregon into the northeast mountains and their foothills and
through the Grande Ronde Valley. Currently expecting gusts of 30-45
mph for the aforementioned locations.
Southerly flow aloft continues with troughing offshore for Friday,
though more uncertainty creeps in for Saturday and Sunday with
guidance not sure whether to take the closed low onshore into the
Pacific Northwest or to track it down the California coast into the
Southwest. Clusters show a roughly even split among ensemble members
with neither solution strongly favored. Plunkett/86
&&
.AVIATION...00Z TAFs...A weather system will produce
periods of showers across the forecast area today with showers
decreasing and ending late afternoon and evening. Expecting mostly
VFR conditions with brief MVFR conditions related to passing
showers. Exception is YKM where some fog is forecast to continue
through the period producing MVFR, IFR, or LIFR conditions. Forecast
winds are light and mostly variable at DLS, YKM, and PSC. Breezy
southwest to southeast winds of 10-20 kts with gusts of 25-30 kts
are on tap for PDT, RDM, BDN, and ALW are forecast to decrease this
evening to 10 kts or less. Another weather system will bring
lowering ceilings and increasing precipitation chances Monday
morning. Plunkett/86
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 36 50 36 44 / 10 50 20 10
ALW 36 49 37 44 / 20 60 30 10
PSC 31 40 31 41 / 10 70 10 10
YKM 29 36 27 37 / 10 80 20 10
HRI 34 47 31 41 / 10 60 10 10
ELN 25 32 25 32 / 10 80 30 10
RDM 34 47 30 42 / 30 70 10 20
LGD 31 40 30 39 / 10 60 20 10
GCD 31 44 27 43 / 10 70 10 20
DLS 35 43 32 41 / 20 80 30 30
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory from 4 AM to 4 PM PST Monday for ORZ049-508.
High Wind Warning from 4 AM to 4 PM PST Monday for ORZ507.
WA...Wind Advisory from 4 AM to 4 PM PST Monday for WAZ029.
&&
$$
SHORT TERM...82
LONG TERM....86
AVIATION...86