Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/22/24
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
858 PM CST Sun Jan 21 2024
.KEY MESSAGES...
- Fog is possible late tonight into Monday morning across western
and into portions of central SD.
- Temperatures forecast 5 to 20 degrees above normal for the second
half of the work week and next weekend.
&&
.UPDATE...
Issued at 848 PM CST Sun Jan 21 2024
Still some light precipitation hugging the ND/SD border across
northern Brown county, continuing to move east. This is in
association with the shortwave energy moving across the eastern
Dakotas. Frederick web cam does show light precipitation on the
imagery. Precip type is likely freezing sprinkles or light sleet,
based on soundings. Probably a better chance for sleet though
given the deeper near-surface cold layer. May need to extend
slight chance (20%) PoPs further east along the state line over
the next few hours. As for fog, models still indicate some
potential over portions of the CWA, but have backed off a bit over
the past few hours.
&&
.SHORT TERM /THIS EVENING THROUGH MONDAY NIGHT/...
Issued at 100 PM CST Sun Jan 21 2024
Winds gusts off the Coteau are continuing to diminish this
afternoon with gusts still ranging between 30-40mph as of 1250pm. By
6pm, forecasted wind gusts should range from 20-35kts, highest in
Deuel county. Webcams in this area still show some light blowing and
drifting snow across the roadways (mainly downslope of the Coteau)
but have improved vastly from this morning.
Short term models along with the ensembles are in agreement with a
shortwave continuing to push east across the Northern Plains late
this afternoon through early Monday morning, along with the
850mb/surface low. These models also indicate light precipitation
with this wave, mainly over Corson county into ND as the precip
tracks east/northeast. The probability of 6hr QPF>0.01" per HREF is
30%, GEFS is 0%, ENS is 25-45%, and the grand ensemble showing 15-
25%. THe highest percentage for these models is over Corson county.
EC/HREF extends the "higher" percentage over northern
Campbell/McPherson counties. Looking at MBG Bufkit sounding and HREF
soundings for Corson county area this evening, the saturated low
level layer (below zero) is very shallow with dry warmer air
aloft(+4C)...quite the inversion, with a little bit of LL lift. With
the freezing drizzle/rain look, this increases confidence as NBM has
this as the prominent Ptype. Potfreezing rain values are between 15-
45% (highest over northern Corson county) along with EC meteograms
Ptype at MBG indicating freezing rain (less than 5% chance here).
RAP/HRRR Cams show this as well with precip brushing our northwest
counties. For the grids, I added in some short term models plus NBM
giving pop chances of 15-30%. With the EC/HREF/Cams eastward extent,
I extended pops eastward to show for this through extreme northern
Mcpherson. This will need to be watched and possible expansion of
pops further eastward (or southward) if needed through 03Z or so.
Ice accumulations look minor (0.02" or less) mainly over western and
northern Corson county.
Otherwise zonal flow aloft for Monday with a shortwave moving across
North Dakota with a ridge just off to our west and a deep trough
over the southern CONUS as split flow continues. This wave could
squeeze out some light precip Monday evening if we can get some
lift. NBM keeps most of the light pops in ND for now, but extreme
northern Corson could get some precip (10-14%). ECAM wants to bring
this precip further south into Dewey county. Also, Rap tries to
bring a chance of mixed precip further into central CWA late Monday
whereas HRRR shows nothing, so left all of this out for now due to
low confidence. A high pressure system will settle over
Manitoba/Ontario area Monday night, shifting southeast on Tuesday
which will keep the area dry.
Overnight lows could be tricky with cloud cover or if any fog
develops, especially over our western/northwest CWA. This would
keep temps warmer. As of now temps will range from around 10 degrees
to the mid teens, warmest west river with highs for Monday ranging
in the 20s, with upper 20s across our western CWA. NBM spread for
max/min temps is still 4-5 degrees and up to 7 degree difference for
our southeastern CWA.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 100 PM CST Sun Jan 21 2024
Not much has changed in the out periods from 24 hours ago.
To borrow from the previous forecaster, split upper level flow
pattern is in full swing when the period opens, with broad/baggy
upper level troughiness across the mid-section of the CONUS. This
implies there will be a number of subtle shortwave circulations to
contend with during the middle to latter part of this week. Always
tough to time the location and precip potential each of these short-
time-horizon systems could generate. So, the low-end PoPs/rather
light qpf approach continues. Doubtless, the lack of significant low
level thermal advection/dry air advection and low level forcing
makes the persistent low stratus/fog potential showing up in the
deterministic and ensembles model output (in AWIPS and BUFKIT)
certainly seem reasonable.
By the middle of this upcoming weekend, it appears the western CONUS
upper level ridge will be attempting to exert influence over as far
as the central plains states, further extending the potential for
above normal temperatures to persist.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 547 PM CST Sun Jan 21 2024
Terminals KABR,KATY,KPIR,KMBG
VFR conditions will prevail early on in the TAF period. Potential
for MVFR/IFR CIGs will increase by Monday morning. Also, the KPIR
area has the possibility for FG/BR (with IFR VSBY) by early
Monday morning. Lesser chance in the KATY area for FG/BR, but not
out of the question. No mention of this in the TAFs for the time
being, but if chances increase during the 06Z TAFs, will include
it in the forecast.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...TMT
SHORT TERM...MMM
LONG TERM...Dorn
AVIATION...TMT
Area Forecast Discussion
National Weather Service La Crosse WI
533 PM CST Sun Jan 21 2024
.KEY MESSAGES...
- Wintry mix of pcpn looks likely for the Mon-Tue time frame,
moreso south of I-90. What falls where and how much remain
question marks. Icing is possible.
- Another shot for precipitation Wed/Thu with current trends favoring
rain or snow...but leaning more rain.
- Mild for the new week with highs in the 30s (maybe 40 for
some) and lows just a few degrees under freezing. A nice
break from recent frigid stretch.
&&
.DISCUSSION...
Issued at 210 PM CST Sun Jan 21 2024
- OVERVIEW: the cold air finally kicks east today with the upper
level flow slated to become more zonal to broad ridging for the new
week. Various shortwave troughs/ridges will sashay west-east across
the CONUS, bringing periodic pcpn chances to the region along with
much milder, above normal temperatures.
- PRECIPITATION CHANCES MON NIGHT/TUE: bits of upper level energy
along with bouts of low level thermodynamics will provide the lift
for pcpn chances, mostly across southern portions of the region
Monday into Tuesday. What pcpn types fall remains the main, and more
difficult question to answer with temperature and saturation
concerns playing the key roles.
North-south running x-sections and bufkit soundings point to a
gradual increase in the near sfc saturation through the day Monday,
deepening Mon night/Tue south of I-90. At the outset, the increase
in low level saturation suggests drizzle/freezing drizzle could
develop...if enough lift in that layer. RAP and GFS more
enthusiastic with this possiblity compared to the NAM, but still on
the weak-side. As the saturation deepens in the south, still some
concern with ice in the cloud, but also warming a loft could
partially/fully melt any frozen pcpn - bringing rain/freezing
rain/sleet back into question. Still, not a ton of clarity in how
this will play out with a lot of moving parts and model disagreements
with temp profiles, saturation, etc. Will continue to let the model
blend dictate pcpn types for now - but may need to add more
drizzle/freezing drizzle chances in the very near future if that
signal continues to show.
Current QPF over the period is roughly 1/10 to 1/4" south of I-90.
How that parts out (snow/freezing/liquid) is uncertain given the
uncertainties in what falls/where. Generally, snowfall amounts
upwards of 1" from northeast IA into central WI look reasonable, and
could be an inch higher if snow would be the dominant ptype. If
icing would be realized, looks like more of a glaze.
Overall, messy scenario continues to be progged for this time period
with confidence still low in the details. If freezing pcpn becomes
more likely, a winter weather advisory will be needed for Monday
night-Tuesday morning.
- ANOTHER SHOT FOR PCPN WED/THU: long range guidance lifts a
shortwave out of the desert southwest Tue, spinning it northeast
across the mid mississippi river valley into the eastern great lakes
by 00z Fri. Similar track to the Mon night/Tue shortwave, but
trending stronger at this time...and a bit more developed. With
milder air already in place pcpn types lean into rain or snow...and
maybe mostly rain. GEFS/EPS soundings point to this, as do north-
south running time/height x-sections. With a southerly fetch of
moisture helping to feed this weather system, the blend of models
pushes upwards of 4/10" of liquid, with a 30% shot for greater than
1/2 in both the GEFS and EPS. Current favored storm track would lay
accumulating snows from southwest MN into northern WI...with any
higher end amounts well north. Plenty of time for change in forecast
track, but good support already within each models` ensemble suite.
- MILD WEEK AHEAD: very consistent signal between the GEFS and EPS
and within each model`s suite of ensemble members for a spate of
very mild days this week. Temp spread between the 25-75% is only a
handful of degrees (in high and low temps), and less than 10 degrees
from the 10-90%. Confidence continues high for at or above freezing
highs into next weekend (some 40 degree days possible) while lows
continue to trend only a few degrees sub freezing.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 533 PM CST Sun Jan 21 2024
Gusty south winds will persist this evening, gradually
diminishing overnight as a low-level jet shifts across the area
and weakens. With indications for lighter near surface flow at
KLSE, did include LLWS for a period late this evening. Expect
predominantly VFR conditions overnight with mainly mid to high
clouds and patchy lower VFR ceilings. Although exact timing
will be refined, MVFR ceilings should expand northward on
Monday, with some potential for IFR ceilings (30-50%) by late
morning, particularly for KRST. Dry conditions will prevail
through the daytime hours on Monday for most locales.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...Rieck
AVIATION...JM
Area Forecast Discussion
National Weather Service Cheyenne WY
433 PM MST Sun Jan 21 2024
.KEY MESSAGES...
- Mountain snow showers expected to continue through Monday.
&&
.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 245 PM MST Sun Jan 21 2024
Pretty quiet weather expected for the remainder of this weekend
and into early next week. Current observations across southeast
Wyoming and western Nebraska show relatively light winds and
temperatures in the 40s to even a few low 50s across the
southern Nebraska Panhandle. Gusty winds near Bordeaux have
subsided below 35 mph with peak gusts only between 40 to 45 MPH
earlier today. Winds have been under 20 MPH elsewhere this
afternoon. Current Visible Satellite loop shows intervals of
high clouds continue to push northeast across the area ahead of
the next weak upper level disturbance, which should keep
temperatures from dropping too low tonight, as was the case last
night. Still expect lower temperatures for areas across far
eastern Wyoming and the northern Nebraska Panhandle since cloud
cover will be limited in these areas. Otherwise, models continue
to be a good agreement, showing split flow developing over the
western third of the United States as we approach the upcoming
work week. This pattern typically results in a storm track well
south of Wyoming with near or slightly above average
temperatures. Two weak upper level disturbances will push east
out of the eastern Pacific and into Wyoming tonight and on
Monday. This will lead to slightly lower 700mb temperatures
across the area, so expect surface temperatures to trend a
little cooler over the next few days but still remain near
average with highs in the upper 30s to middle 40s.
The only other minor concern is high resolution guidance is
showing some scattered snow and rain showers developing over the
higher terrain early Monday morning and later Monday afternoon,
likely ahead of the two individual upper level disturbances
forecast to push across the area tonight and later on Monday.
Precipitation coverage looks convective in nature, but model
soundings show marginal conditions for snow/rain shower activity
with poor moisture profiles off the surface and a shallow
boundary layer. Not much, if any, forcing is noted on 700mb to
500mb model analysis. Therefore, kept POP above 15 percent only
in the mountains with POP near 10 percent for the lower
elevations for now. Added some wording for flurries, but limited
areal coverage to areas near the mountains. The only other
notable change to the previous forecast is the potential for
fog Monday night and early Tuesday morning. Models show light
winds becoming southerly after midnight Monday night. Expect
dewpoints to remain in the 20s with light winds and a melting
surface snowpack. HRRR and Short Range Ensemble guidance
increase the chance of fog across east central Wyoming and
western Nebraska early Tuesday morning, so added areas of fog to
this area with favorable surface conditions.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Issued at 159 PM MST Sun Jan 21 2024
A mainly quiet weather pattern will carry us through next weekend
with generally mild temperatures and limited precipitation chances,
though there will be brief exceptions.
On the synoptic scale, a split flow regime will largely dominate the
CONUS for much of the week ahead. A messy, split trough will meander
across the west on Wednesday, though most of the vorticity will be
to our south across the Four Corners states. 700-mb temperatures
around -4 to -6C across the area will support highs on Wednesday
near to slightly above seasonal normals. Most of the lift will steer
clear of our area, but weak orographic lift in the presence of a
moist 700 to 300-mb layer of the atmosphere will support a few
mountain snow showers Wednesday into Thursday. A slightly more
organized northern branch shortwave is expected to push into the
west on Thursday, as ridging starts to build in just offshore. While
again, the vorticity will mostly miss our area, light mountain snow
showers are likely to continue into as late as early Saturday. Only
about 20% of ensemble members get the mountains to advisory criteria
snowfall during the 48-hour period ending Saturday morning, but
almost all have at least some light snowfall accumulation in the
higher terrain. The lower elevations will not see much from this,
with only about 20% of members spreading any measurable
precipitation east of the Laramie Range. While we will continue to
monitor, the precipitation impacts from this late week event look
limited. A cool down is considerably more likely, but again, most
guidance shows this being fairly minor. 700-mb temperatures in the
ensemble mean drop to around -10C by 00z Saturday, which is expected
to lead to slightly colder temperatures Thursday PM through Saturday
AM. While the cool down will probably be noticeable, it won`t be
nearly as strong as the most recent arctic cold front. Instead,
expect temperatures to sag perhaps just a few degrees below seasonal
averages. This will also be short lived, as guidance now strongly
supports a highly amplified ridge building over the western CONUS
this weekend. Ensemble mean 500-mb heights exceed the 90th
percentile of climatology by Sunday for much of the area, with 700-
mb temperatures surging to around 0C by the end of the day Sunday.
While Sunday`s surface temperatures may initially lag behind the
warming aloft, expect this to be the start of a considerable warming
trend.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 421 PM MST Sun Jan 21 2024
VFR is expected at most terminals through the forecast period. A
weak weather disturbance will slide to our south through Monday,
and it will bring reduced CIGs for KRWL. Expect VFR to
transition to MVFR between 9z-15z Monday morning. The NE
Panhandle terminals will see primarily VRB winds through 12z
Monday, with isolated patchy FG being possible at times.
Confidence is not high with FG becoming widespread to reduce VIS
at this time of inspection.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...TJT
LONG TERM...CLH
AVIATION...BW
Area Forecast Discussion
National Weather Service Hastings NE
542 PM CST Sun Jan 21 2024
.KEY MESSAGES...
- Although bitter cold/multiple rounds of snow are in our
rearview mirror, we are "trading it in" for a milder weather
pattern, BUT one frought with a very tricky forecast
especially Mon-Wed night regarding fog potential (perhaps
widespread/dense at times) and intermittent chances for a
wintry mix that could slicken roads at times (probably most
favoring light freezing drizzle/freezing rain and less-so
measurable snow).
- Due to the above, it is looking increasingly likely that parts
of the Mon-Wed time frame will eventually necessitate the
issuance of Dense Fog Advisories and/or Winter Weather
Advisories, but with forecast uncertainty still running
above-average, have held off for now.
- Already tonight, our far southeast coverage area
(CWA)...mainly southeast of an Osborne-Hebron line...carries a
slight (10-20%) chance of light freezing drizzle/freezing
rain, but given such low confidence in occurrence have also
held off on a formal Winter Weather Advisory for this.
- Temperature-wise, while it will FOR SURE be warmer than
lately, the widespread clouds that will likely punctuate much
of the week, along with lingering snow cover, could easily
keep us a bit colder than currently forecast during the day
and conversely perhaps a bit warmer than currently forecast
overnight. Still though, most areas will see highs in the 30s
the next several days and lows in the 20s on most nights.
&&
.DISCUSSION...
Issued at 432 PM CST Sun Jan 21 2024
-- PRIMARY CHANGES IN THIS FORECAST PACKAGE VERSUS THE PREVIOUS
(EARLY-AM) ONE:
1) The majority of changes were made to various parts of the
Monday daytime-Wed night time frame, including the introduction
of "patchy" to "areas" of fog (only through Tues AM for now)
and increasing chances for at least a light wintry mix
especially for the Mon night-Tues AM and Tues night-Wed time
frames.
2) Temperature-wise, if anything daytime highs were nudged
downward at least a few degrees (particularly Wed-Sat), as it`s
looking increasingly-likely that the combination of plentiful
cloud cover (esp Mon-Fri) and lingering snow cover will hold us
back somewhat. With better potential for more widespread
sunshine for next weekend, Sat-Sun actually feature the
overall-best chance of much of our CWA making it into the upper
30s-low 40s (possibly even upper 40s/near 50 in southwest
counties for Sunday).
-- ADDITIONAL "BIG PICTURE" FORECAST COMMENTS (including all
further discussion of the longer term periods Thursday-
Sunday):
1) Needless to say, the vast majority of forecast uncertainties
focus clearly on the Mon-Wed night time frame, including just
how impactful/widespread fog will become, along with how
impactful the various chances for a wintry mix will be (see
shorter-term specific paragraphs below for more details).
2) Given the arrival of milder air, we know there are some
concerns regarding at least minor/nuisance issues with river ice
break-up and possible ice jam flooding along the Platte/Loup
River systems. However, because we are only talking a MARGINAL
warm-up during this next week (highs mainly 30s/lows mainly
20s), we are not expecting significant issues given that ice
break up/snow melt will be quite gradual. Obviously something to
monitor, however.
3) Our forecast remains dry/void of any precip chances Thursday
daytime-Sunday, and this continues to carry relatively high
confidence per both the latest deterministic ECMWF/GFS runs and
also ECMWF ensemble, which keep late-week/weekend precip
chances mainly off to our south.
4) Confidence is high that one thing that will be notably-
lacking over these next 7 days is wind (today was/is the
windiest day we will see for a while), with sustained speeds on
most upcoming days no more than 10-15 MPH (which will surely
heighten our fog potential as well due to lack of low-level
mixing).
- SHORTER-TERM FORECAST DETAILS FOCUSED SOLELY ON TONIGHT
THROUGH WEDNESDAY NIGHT:
-- CURRENT/RECENT WEATHER SCENE AS OF 4 PM SUNDAY:
Overall today has turned out very much as expected (fairly windy
from the south, BUT notably warmer...some 20+ degrees!...than
yesterday). In the big picture of the mid-upper levels, we are
under broad southwesterly flow aloft, downstream from a broad
trough over the western United States that will send a parade of
mainly weak/low amplitude disturbances into the Central Plains
(but ESPECIALLY areas just to our south/east) over the coming
days before our flow aloft turns more northwesterly Thursday
onward (and thus the beginning of a higher-confidence dry time
frame). At the surface, A tight pressure gradient set up today
between a strong departing high pressure system now centered
over the southeast states/OH Valley area, and a High Plains lee
trough. This gradient has driven moderately-windy conditions
today (especially across our central/eastern CWA), with
sustained speeds commonly 15-25 MPH/gusts 25-35 MPH. Although
we`ve had various reports of these winds blowing "streamers" of
snow across roads at ground-level (likely causing patchy icy
spots), the lack of widespread blowing snow/visibility
reductions has precluded consideration of any kind of formal
Winter Weather Advisory. High temps are on track to top out mid-
upper 20s most areas, but with low-mid 30s in several
southern/far western counties.
- THIS EVENING-OVERNIGHT:
Aloft, the first of several disturbances over the coming days
(this one quite weak) races across our area overnight. While
confidence is high that the vast majority of our CWA (and
perhaps all of it) remains dry, various models (including higher
res HRRR/NAMNest that our far southeast zones (mainly SE of an
Osborne-Hebron line) could get clipped by a brief period of
light freezing drizzle/freezing rain that should MAINLY focus
east-southeast of our CWA altogether. As a result, have
maintained very low-end 10-20% chances (PoPs) for this possible
light icing in our far southeast. Have this slight chance for
light icing covered in our Hazardous Weather Outlook (HWOGID),
but did not have the confidence to issue a formal Winter Weather
Advisory. Next few shifts will have to keep a close eye on this,
however. In other departments, winds will remain southerly
overnight, but will become lighter with time (especially post-
midnight), with late night/early Mon AM sustained speeds no more
than 5-15 MPH (lightest west/strongest east). Low temps are
little tricky and will likely be impacted by cloud cover (skies
overall mostly cloudy which should hold them up) and wind speeds
(lowest speeds west will foster the greatest drop). Have most of
the northwest 2/3rds dropping into the 17-23 range, but with
milder lows mainly 24-27 in the southeast 1/3.
- MONDAY DAYTIME:
While no actual precipitation is expected (have maintained a dry
forecast through 00Z/6 PM), various models strongly suggest that
a deck of low clouds and/or fog will gradually build north-
northwestward across especially the east/southeast 1/2 of our
CWA over the course of the day. Forecasting fog intensity is
almost always an adventure especially beyond 6-12 hours, but
typically-aggressive visibility progs such as from the HRRR
suggest that fog could become dense. For now, have at least got
the ball rolling with a generic "patchy fog" mention. While
southerly breezes around 10 MPH will be common in the morning,
speeds will decrease closer to 5 MPH as the afternoon wears on
and turn more southeasterly...also more favorable for low
clouds/fog formation. Am a little concerned high temps may be
aimed a touch warm, but have most of the CWA aimed into the
32-35 range.
- MONDAY EVENING-OVERNIGHT:
This really where the forecast uncertainty starts to ramp up,
especially with regard to precip chances. The next, and somewhat
stronger disturbance rides up and into our region from the
southwest. At the very least, confidence is increasing that we
will probably see fairly widespread (and very possibly dense)
fog development in a very light east-northeasterly wind regime.
Of lower confidence are precip chances, with the latest
ECMWF/GFS largely keeping the majority of precip JUST to our
east-southeast, while other models (including NAM/NAMNest/HRRR)
are more aggressive in gradually spreading a wintry mix (most
likely freezing drizzle/freezing rain) into much of our CWA as
the night wears on. Actual forecast precip (QPF) amounts are
light (mainly under 0.05"), but this could be enough to cause
slick roads with low temps forecast to bottom out mainly in the
25-30 range. There is a non-zero chance that a bit of sleet or
even outright-snow could also occur (especially if precip ends
up being a bit heavier than currently expected), but for now
this is a less likely scenario.
- TUESDAY DAYTIME-NIGHT:
Odds favor MOST of the CWA being void of measurable precip
during the daytime hours, and as a result PoPs are only 10% at
this time. However, with continued light easterly (upslope)
breezes, this will be a favorable environment for continued
widespread fog (possibly dense), along with light
drizzle/freezing drizzle (depending on exact surface temps), so
have at least introduced slight drizzle/freezing drizzle chances
to the entire CWA. High temps very similar to tomorrow (mainly
32-35). Tuesday night (especially post-midnight), PoPs ramp up
again as another upper wave moves in from the southwest. Again,
considerable variability in coverage/amounts of precip results
in a low-confidence forecast here, with the GFS solution
considerably more aggressive than the latest NAM/ECMWF. At least
for now, have geared precip type toward light freezing rain or
rain, but again cannot rule out pockets of snow/sleet. There
could also be continued widespread fog, but because we typically
don`t insert fog into the official forecast beyond 36 hours,
this is not formally included for now. Low temps aimed 26-31
most places.
- WEDNESDAY-WEDNESDAY NIGHT:
As if uncertainty isn`t high enough for exactly how Mon-Tues
will play out, you can guess that forecast (and forecaster)
confidence for how Wed-Wed night plays out is on the low end of
things at this time. However, various models DO agree that this
should be the "last hurrah" of our overall-gloomy/foggy/at times
wet/maybe icy early-mid week period, as the final (and primary)
upper wave of the week to affect our area arrives from the
southwest. Model differences abound, with the ECMWF/GFS giving
us a bit higher QPF compared to the mainly dry NAM solution. The
official forecast mainly leans on a mix of light freezing
rain/rain for now, but yet again a low chance for snow is not
out of the question. Temp-wise, it`s rinse and repeat with highs
mainly low-mid 30s and lows Wed night mainly mid-upper 20s.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 527 PM CST Sun Jan 21 2024
VFR conditions are expected to continue through the overnight
hours as passing high clouds and steady south winds of 15-20KTS
continue. Late in the night, models are indicating some low
level clouds encroaching on the terminals, with the potential
for fog increasing during the morning hours as the winds
gradually shift more southeasterly. This should lead to MVFR to
IFR CIGS by 22/16Z...and IFR VSBYs and BR/FG filling in during
the afternoon hours. Once settled in, this low level cloud
cover and off and on foggy conditions could persist across the
region for several days based on model time height data and SREF
visibility probs.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
DISCUSSION...Pfannkuch
AVIATION...Rossi
Area Forecast Discussion
National Weather Service Grand Rapids MI
855 PM EST Sun Jan 21 2024
.KEY MESSAGES...
- Wintry mix looking likely for Monday into Tuesday
- Rain for Wednesday night into Thursday night
&&
.UPDATE...
Issued at 855 PM EST Sun Jan 21 2024
Have tweaked the forecast slightly, only to bump up the timing
of the onset of the snow for late tonight, instead of during the
Monday period. This is all based on the latest runs of the hi-
res models including the HRRR and RAP.
Dry air will keep the snow at bay a little at the onset, but
once it becomes steady enough, it will reach the ground. Low
level moisture then moves in quickly to help with the steady
snow after 12z.
&&
.DISCUSSION...
Issued at 205 PM EST Sun Jan 21 2024
- Wintry mix looking likely for Monday into Tuesday
One weakening mid level shortwave and associated low level jet
moves into the CWA Monday morning. The increasing moisture and
deeper lift will support a period of what looks like mostly
snow with perhaps some sleet. Most locations are progged to see
an inch or less during the day on Monday so we are not planning
headlines at this time. Localized impacts look possible as the
surface temperature will be well below freezing.
There is a risk for freezing drizzle starting late afternoon
Monday. This is when the DGZ becomes unsaturated while low level
lift and moisture persists. Confidence on its occurrence was
low at this time. However as we go through the evening and into
the night, the lift increases once again as a second mid level
shortwave tracks in from the south southwest. This feature will
draw up abundant moisture from the Gulf which will enhance the
precipitation rates. FGEN was noted especially north of Grand
Rapids later Monday night into Tuesday morning along with a
coupled upper jet. Peak lift is shown in the 09z to 18z period
Tuesday. Forecast soundings support a wintry mix for the region
mainly south of a Grand Rapids to Lansing line. We could end up
with a tenth of an inch of freezing rain along the Interstate 94
corridor, with locally more. Meanwhile, along and north of the
Grand Rapids to Lansing line, snow looks to be the main
precipitation type. Ensemble mean snow amounts for Grand Rapids
vary with the models and the GFS is the lowest, suggesting
around an inch, while the other models are generally in the 2 to
4 inch range. Snow ratios may fall short of the 10 to 1 that
the models use. However, given the favorable ingredients this
system has to work with, we could end up with a swath of higher
snow amounts. Also, slight shifts in this wintry mix/snow line
may still occur as this system nears. Impacts are looking
likely, starting after midnight Monday night unless the
freezing drizzle ends up being widespread. The Tuesday morning
commute is looking like it will be especially impacted.
- Rain for Wednesday night into Thursday night
A mid level shortwave tracks northeastward through the Great
Lakes Region during this time. Forecast soundings support rain
as the precipitation type. PWAT values will be well above
normal, with model ensemble values pushing 0.8 to 1.1 inches.
These values will be around 3 times the normal amounts. Thus a
risk for some of this rain to be heavy exists. The right
entrance region of a strong upper level jet will be in place to
enhance the lift. The winds through a relatively deeper layer of
the atmosphere are progged to be nearly parallel to the frontal
zone. If this happens, it could lead to some training cells which
would be a concern. This will be something to keep an eye on
going forward. There is still a lot of spread in the model
ensemble qpf values. The GFS is overall the weakest with this
feature in our area with mean 24 hr qpf values generally a
quarter inch or less. The Canadian and High Res Euro are both
higher with the rainfall amounts.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 644 PM EST Sun Jan 21 2024
We start this forecast period out with almost all of the area
seeing VFR conditions. The exception to this are MVFR conditions
at KMKG with some clouds off of the lake. These conditions will
continue through the night.
Light snow will start to develop at KMKG around 11-12z or so,
and spread across the remaining terminals through 16-17z. It
will take a couple of hours after the snow moves in to see
conditions deteriorate fairly quick, likely going down to IFR in
visibilities, then ceilings.
We will see the snow come to an end starting around 17-18z and
progress gradually through the area. This could turn into some
freezing mist/freezing drizzle with temperatures likely below
freezing. This will remain accompanied by low end MVFR to IFR
conditions through the end of the forecast period.
&&
.MARINE...
Issued at 205 PM EST Sun Jan 21 2024
A southwesterly low level jet will be moving in tonight into
Monday. This will result in winds increasing to Small Craft
Advisory criteria. Since its warm air advection, the mixing
height will be limited. As a result we do not expect numerous
gale force gusts at this time.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 5 AM EST Tuesday for LMZ844>849.
&&
$$
UPDATE...NJJ
DISCUSSION...MJS
AVIATION...NJJ/Thomas
MARINE...MJS
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
826 PM CST Sun Jan 21 2024
.KEY MESSAGES...
* Winter Weather Advisory in effect for nearly all of central and
southeast Illinois from late tonight into Monday night.
* 30-60% chance of ice accumulations greater than 0.01"
along/south of I-74 and along/west of I-57 by 8am Monday.
* Both the Monday morning and Monday evening commutes will likely
be impacted by slick conditions on area roads.
&&
.UPDATE...
Issued at 825 PM CST Sun Jan 21 2024
This evening, water vapor imagery reveals a shortwave trough
lifting across Oklahoma which is progged to lift across the mid
Mississippi Valley late tonight. Latest suite of CAMs are in good
agreement on precipitation entering the ILX forecast area across
the lower Illinois River Valley between 3am and 6am. Temperatures,
meanwhile, have been holding steady or rising slightly, a trend
that will continue overnight. Precip is on track to start out as
snow or a wintry mix that includes sleet and freezing rain before
transitioning to primarily freezing rain or freezing drizzle late
in the morning. Winter Weather Advisory appears to be on track.
Deubelbeiss
&&
.DISCUSSION...
Issued at 251 PM CST Sun Jan 21 2024
20z/2pm surface map shows a sprawling ridge of high pressure
extending from Quebec to the Gulf Coast...with increasing S/SE
return flow noted across the Midwest. Winds have been gusting
20-25mph through the afternoon, which has helped push temperatures
well into the 20s. Temperatures will drop a couple of degrees
after sunset: however, as winds veer to S/SW and continue to be
strong/gusty, readings will rise back into the lower to middle
20s by dawn Monday. Models have been consistently showing WAA
precip developing and spreading into the area from the southwest
after midnight. The main change is with the thermal/moisture
profile as RAP forecast soundings now suggest deeper moisture and
the presence of ice crystals during precip onset. As a result,
think a mixture of light snow and sleet will develop across the
Illinois River Valley after 2am...then spread eastward to I-57 by
dawn. Forecast soundings suggest a gradual loss of ice crystals
during the morning, which would mean a transition to mostly
freezing rain. At the same time, the initial surge of precip will
likely diminish in intensity and areal coverage and perhaps even
come to an end across much of the KILX CWA toward midday. Given
the initial mixed phase of the precip, the Monday morning commute
may not be quite as icy as initially expected. HREF Grand Ensemble
indicates a 30-60% chance of ice accumulations greater than 0.01"
along/south of I-74 and along/west of I-57 by 8am Monday. This
may not sound like a lot of ice, but will be enough to create
slick spots on untreated roads, overpasses, and parking lots.
Motorists are therefore advised to drive with caution and plan on
extra time to arrive at their destinations for the morning
commute. A Winter Weather Advisory has been issued for nearly the
entire CWA except for Richland and Lawrence counties accordingly.
After a lull in the steady precip around midday, another surge of
WAA moisture will spread into the area from the south during the
late afternoon/evening. Surface temps will climb into the lower
30s, but will likely remain near the freezing mark. Ground and
pavement temperatures will most certainly remain below freezing,
so the threat for additional icing will continue for the evening
commute. Think most impacts will be felt on secondary/rural roads
as well as sidewalks and parking lots: however, caution is advised
if you must travel. Surface temps will gradually climb into the
middle 30s Monday night, but this likely will not happen across
the far northern CWA until after midnight. Have therefore extended
the advisory until 6am Tuesday for locations along/north of the
I-74 corridor. Storm total ice accumulations will generally be
around one tenth of an inch across central Illinois.
Rain showers will persist through Tuesday morning before pushing
eastward and temporarily ending across much of the area Tuesday
afternoon/night. Additional short-wave energy will generate more
rain chances Wednesday into Thursday before conditions finally dry
out Thursday afternoon into next weekend. Temperatures will remain
mild through the extended...with highs topping 40 degrees across
the board Wednesday through next Sunday. The warmest day of the
forecast period will be Thursday when highs will top the 50
degree mark along/southeast of a Champaign to Springfield line.
Barnes
&&
.AVIATION... (For the 00z TAFs through 00z Monday Evening)
Issued at 528 PM CST Sun Jan 21 2024
An upper level disturbance will lift across the region bringing
periods of wintry precipitation to central Illinois. The wave will
lift across the region late tonight into Monday morning. Precip
may initially be frozen, a mix of snow and sleet, before
transitioning to freezing rain or freezing drizzle. Precip will be
heaviest in the morning then will taper off to a light rain or
drizzle most of the remainder of the day before a second stronger
wave arrives Monday evening. Winds will generally be out of the
south through the period with gusts into the low to mid 20 kt
range, though sporadic in frequency at times. IFR or near IFR
ceilings will also overspread the terminals mid to late Monday
morning and persist through the remainder of the period.
Deubelbeiss
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 3 AM Monday to 6 AM CST Tuesday for
ILZ027>031-037-038-043>046-055-057.
Winter Weather Advisory from 3 AM Monday to midnight CST Monday
night for ILZ036-040>042-047>054-056-061>063-066>068-071.
&&
$$
Area Forecast Discussion
National Weather Service North Platte NE
516 PM CST Sun Jan 21 2024
.KEY MESSAGES...
- Increasing moisture advection Monday into Tuesday will lead to
the development of freezing fog with a slight chance for light
freezing drizzle. This is expected across the southeastern
half of the area.
- An upper trough lifting from the Great Basin into the Plains
will bring a chance for light rain, possibly freezing rain
across southeastern areas Wednesday into Wednesday evening.
Chances for fog will also exist Tuesday night into Wednesday
morning.
- Dry with seasonable temperatures in the 30s to 40s expected
Thursday through Saturday.
&&
.SYNOPSIS...
Issued at 225 PM CST Sun Jan 21 2024
Surface high pressure was currently centered over the Ohio
Valley. Southwesterly winds were occurring across western
Nebraska bringing in slightly warmer temperatures, especially
across the west. High cloudiness was beginning to move into the
area. Temperatures at 2 pm CST, ranged from 47 at Crescent Lake
(Garden County) to 22 at O`Neill.
&&
.SHORT TERM /THROUGH MONDAY/...
Issued at 225 PM CST Sun Jan 21 2024
A trough of surface low pressure will reside across the region
tonight with partly cloudy skies, mainly from high cloudiness.
Lows should range mostly in the upper teens as winds remain
light west to southwest.
A weak southwest flow aloft on Monday with light and variable
winds. H85 temperatures will range from 5C to 7C. The lack of
near surface mixing will limit highs to the mid 30s to low 40s.
The warmer temperatures will be across the eastern panhandle
and southwest. Went below the NBM, blended with CONShort for
highs. Skies should remain partly sunny.
A backdoor cold front will drop southward into the area Monday
night as low level moisture is advected into the area. The
latest mesoscale models HRRR and RAP as well as SREF
probabilities as high as 90 to 100 percent all support
fog/freezing fog across much of western and north central
Nebraska. Some weak lift would also support a slight chance for
freezing drizzle later Monday night into Tuesday morning. The
main area of concern will be across the southeastern half of
the area.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
Issued at 225 PM CST Sun Jan 21 2024
Fog and freezing fog, possibly light freezing drizzle will
linger Tuesday morning as stratus will persist into the
afternoon. This will keep temperatures on the cool side mainly
in the mid 30s.
An upper trough over the Great Basin will emerge onto the Plains
Tuesday night and Wednesday. A southerly flow in the lower
levels Tuesday night will maintain moisture advection.
Additional fog development is favored Tuesday night into
Wednesday morning. A Southern Stream system will lift
northeastward Tuesday night through Thursday. With timing
differences, the latest NBM brings as low chance for light rain,
possibly light freezing rain Wednesday into Wednesday evening.
Highs Wednesday mainly in the upper 30s.
As moist low level advection persists atop lingering snowpack,
fog will again be possible Wednesday night into Thursday
morning. Highs Thursday from the mid 30s to low 40s.
Patchy slick spots on elevated surfaces are possible each night
into the morning hours, as temperatures fall below freezing in
the overnight hours.
By Friday and Saturday, the upper trough is expected to be
positively tilted from the Central and Southern Plains across
the Great Lakes. While dry conditions are expected, some
cloudiness will persist with highs seasonable in the mid 30s to
mid 40s (warmer across the west).
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 513 PM CST Sun Jan 21 2024
VFR conditions prevail across western and north central Nebraska
through the period. Winds will remain light at 6kts or less,
generally out of the southwest/west overnight before backing
towards the northeast/east during the day on Monday.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Roberg
SHORT TERM...Roberg
LONG TERM...Roberg
AVIATION...Viken
Area Forecast Discussion
National Weather Service New Orleans LA
933 PM CST Sun Jan 21 2024
...New MARINE...
.SHORT TERM...
(This evening through Monday night)
Issued at 245 PM CST Sun Jan 21 2024
Starting off with late this afternoon - main focus continues to
be on the degree of low/mid-level clouds around 6000-7000ft AGL or
roughly between 850 to 750mb aloft. This relatively thin layer of
moisture, originating from the deeper SW moist return flow across
Texas was caught up in the transitional westerly low/mid- level
flow aloft and was able to press east, winning over the dry
tropospheric profile in place. Big adjustments were needed for
MaxT`s for western areas in a modified (shorter) diurnal
curvature. Recent RAP guidance continues to promote enough
moisture in this layer east this evening, and have clouds
increasing overnight. While it will not necessary be thick cloud
cover on the onset, it could thicken with time to slow the
temperature trend overnight. Deterministic NBM came in on the
warmer side but did edge towards the 75th percentile to
accommodate building insolation plus gradient surface winds
remaining elevated enough to promote turbulent PBL mixing
(increasing somewhat going into daybreak Monday). It`ll still lead
to colder locations reaching the 30`s, mainly for northern areas
and perhaps protected drainage basins across the Pearl
River/Pascagoula basins.
Going into the day on Monday mostly cloudy, if not completely
overcast as model soundings indicate moistening in multiple
layers aloft, all within an increasing WAA/moisture return regime.
This is all out ahead of a rather complicated upper-level pattern
taking place. Model guidance 12Z MON highlights a rather broad
southwesterly flow pattern as mentioned earlier dominating the
southern US, with numerous embedded (albeit rather weak)
impulses/PVA within the progressive SW/NE flow. This will promote
enough dynamic lift in conjunction with deepening tropospheric
moisture to lead to widespread showers over the ArkLaTex region
during the day on Monday. Again, individual/organized embedded
impulses will be largely disorganized which will hider any
distinct or organized surface low genesis, leading to a very
disorganized mass of rain approaching our area from the west later
in the day into Monday night. Further out ahead, broad/mixed PVA
impulses over the Gulf will promote coastal shower development
overnight into early Tuesday, spreading north. Not anticipating
much, if any threats this early on as most of Monday will be dry,
but starting Tuesday, we may start to see our first off/on round
of showers at times. Otherwise, with Monday being mainly cloudy,
did lower temperatures some to account for the thicker cloud
cover, towards the 25th percentile but still brings locations into
the 60`s with a rather cool/mild but cloudy day.
&&
.LONG TERM...
(Tuesday through Saturday night)
Issued at 245 PM CST Sun Jan 21 2024
By Tuesday morning, the progressive nature of southwest flow aloft
will already have scattered showers across much of the area. The
first impulse in the larger-scale trough over the southern plains
will allow advection of warm and moist air ahead of the trough into
the area. This will allow the temperatures to be 8-10 degrees above
average of this time of year. Temps were blended towards the 75th
percentile due to the expected warm air advection during the day on
Tuesday. Although we will have showers across the area on Tuesday,
the axis of the heaviest rain looks to be to the north and west of
us closer to the system`s cold front on Tuesday. If the trough was a
little more progressive and the front gets into our area on Tuesday,
we can see a higher rain totals as the upper-level flow parallels
the front such that the rain will keep training along the front. Low-
level thermodynamic looks to be poor for any organized convection as
low-level lapse rates look to be in the 4-5 C/km range.
Wednesday will be largely the same as Tuesday as the lead impulse
gets kicked and phased out by another impulse in the trough across
the southern plains. We will still be in southwest flow with warm
and moist air being advected into the area, so expect temps to
remain 8-10 degrees above average. The front still appear to be
northwest of the area, and such is where the heaviest rain sets up.
Low-level thermodynamics improve to 5.5 C/km and we have adequate
parameters for organized convection. MLCAPE looks to be in the 100-
1500 j/kg range and low-level shear is in the 200-250 m2/s2 range in
both 0-1km and 0-3km SRH. Although those ingredients are there,
forcing seems to be the issue Wednesday. Heights looks like they try
to fall during the afternoon on Wednesday, but they mostly stay the
same. Without the forcing, we could only see spinning showers that
do not amount to anything. However, with the proper forcing, we
could see some rotating storms on Wednesday during the afternoon.
The heavy rain threat looks to increase during the day on Thursday
as the next impulse kicks the trough a little further to the east,
bringing the aforementioned cold front east and into our area
Thursday evening. To give an idea of how much moisture this front
will have to work with as it gets into our area, the expected PW is
around 1.5-1.75 inches along the front. The max for that date in our
sounding history is 1.74 inches, showing how this amount of moisture
is expected to be near record on Thursday. With all of that moisture
to work with and the upper-level flow largely paralleling the
front, the front will crawl through the area on Thursday. Due to the
amount of moisture and the slow progression of the front, flash
flooding seems to be the highest concern on Thursday evening. Severe
weather does not seems as much of a concern because the surface
front seems to outrace the 850mb front and the storms along the
front stays elevated.
The front looks to hang up along the coast on Friday, and that is
where the rain will be concentrated. Most of the area will only see
light showers during the day Friday as the elevated front pushes
through. The last kicker to get the trough out of here comes on
Friday evening and into Saturday and drier air filters into the area
and temps return closer to normal. Rain chances go down with the
drier air moving in and it looks dry for the rest of the weekend and
into next week.
&&
.AVIATION...
(00Z TAFS)
Issued at 536 PM CST Sun Jan 21 2024
VFR conditions prevail with low to mid level clouds having built
in from south and west and expected to remain for this cycle.
Increasing low level moisture will bring MVFR condtions to all
terminals later in period. Winds are in process of veering from
current easterly to southeasterly becoming stronger and gusty by
end of the period.
&&
.MARINE...
Issued at 932 PM CST Sun Jan 21 2024
Surface winds are expected to increase through the night into the
day on Mon day ahead of the next storm system organizing to the
west. Progressive E to eventual SE onshore flow will lead to
increased fetch and waves/seas responding by building with time,
reaching 7ft + for outer 20-60nm zones increasing into Tuesday.
Small craft hazards are now in effect due to increased surface
winds and attendant hazardous waves/seas, and could be required
going into late week as we remain in an active pattern. Otherwise,
occasional showers and storms can be expected Monday night thru
late-week and into the weekend, where some storms may be heavy at
times. [KLG/DSS]
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 31 59 52 68 / 0 10 70 70
BTR 40 67 58 74 / 0 10 70 70
ASD 35 64 54 71 / 0 10 40 60
MSY 45 65 58 71 / 0 10 50 60
GPT 35 61 53 68 / 0 0 30 50
PQL 31 62 52 70 / 0 0 30 40
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...Small Craft Advisory from 3 PM Monday to 6 AM CST Tuesday for
GMZ530-532-534.
Small Craft Advisory from 6 AM Monday to 6 AM CST Tuesday for
GMZ536-538-552-555-557-572-575-577.
Small Craft Advisory until 6 AM CST Tuesday for GMZ550-570.
MS...None.
GM...Small Craft Advisory from 3 PM Monday to 6 AM CST Tuesday for
GMZ532-534.
Small Craft Advisory from 6 AM Monday to 6 AM CST Tuesday for
GMZ538-552-555-557-572-575-577.
Small Craft Advisory until 6 AM CST Tuesday for GMZ570.
&&
$$
SHORT TERM...KLG
LONG TERM....JZ
AVIATION...DS
MARINE...DS
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
619 PM CST Sun Jan 21 2024
.KEY MESSAGES...
- Flurries or a light wintry mix overnight tonight.
- Well-above normal temperatures this week through the end of
the month.
- Increasing chances for light rain or snow Wednesday night
into Thursday.
&&
.DISCUSSION...
Issued at 135 PM CST Sun Jan 21 2024
Warm advection is in full force this afternoon as brisk south
winds are allowing for temperatures to reach the low 20s across
much of the area. Wind gusts of 30-40 mph will continue through
the afternoon, with a few gusts as high as 50 mph possible
across the higher terrain of the Buffalo Ridge across southwest
Minnesota. Wind gusts will decrease overnight but will still
remain around 20 mph. The continued warm advection will also
lead to enough forcing and low-level moisture for light
precipitation to develop overnight. Flurries or light snow looks
most likely, but patchy freezing drizzle is possible if the
lift is too weak for ice crystal development.
Temepratures continue to warm Monday with highs approaching the
30s, and a few spots warming above freezing across southern
Minnesota & western Wisconsin. This begins a stretch of well-
above normal temperatures through the end of the month, along
with an extended stretch of cloudy weather similar to our last
warm stretch in late December/early January. Conditions will be
nearly identical for the next several days, with daytime highs
in the mid to upper 30s and overnight lows in the mid 20s to low
30s. The only chance for precipitation this week comes midweek,
as two weather systems impact the Midwest Tuesday through
Thursday. The first system continues to trend southeast of the
area, with a slight chance of light rain or snow across
southeast Minnesota & western Wisconsin depending on the
northern extend of the precip shield. meanwhile the second
system has trended a bit more to the northwest, which brings an
increasing chance for light rain or snow Wednesday night into
Thursday. Snow chances will be greater during the overnight
hours when temperatures dip below freezing, while rain is more
likely during the daytime. Looking even farther ahead the warm
pattern amplifies around the end of the month, with even warmer
temperatures expected to start February.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 554 PM CST Sun Jan 21 2024
Pretty substantial changes to the TAFs with the 00z set to
greatly improve cigs through the day on Monday. The biggest
reason is if you look upstream of us in the southerly flow, the
nearest MVFR cigs are just now moving into the KC area. Looking
at forecast low level flow fields, this moisture down by KC will
be transported toward EAU Monday morning, so the WI terminals
are the one place we continue to bring MVFR cigs into Monday
morning. In MN, we delayed onset of MVFR cigs to when winds
switch to a more northerly direction, as winds this direction
will help drop the lower cigs over northern MN down into the MPX
terminals. One thing that has not changed is we`ve kept all TAFs
dry, with low levels remaining to dry to support precipitation.
KMSP...21z RAP doesn`t show enough moisture to support stratus
at MSP until Tuesday morning. In addition, the trend with cigs
from the LAV has been to back away from the stratus on Monday,
so with those two factors in mind, considerably improved the cig
forecast for MSP on Monday. The key to watch will be trends
with the stratus moving into KC, if that does indeed slide off
to the east of MSP as currently expected, then it will be a
while before we see significant cig reductions at MSP. Though we
keep it VFR through Monday, it`s still possible that the lower
cigs coming up from KC may at least briefly impact MSP in the
morning. Hopefully with the 6z TAFs we`ll be starting to get a
better feel for where the western edge of that stratus will
setup.
/OUTLOOK FOR KMSP/
Tue...MVFR cigs likely, chc IFR cigs. Winds E 5-10 kts.
Wed...MVFR cigs likely. Chc IFR/-RA late. Wind SE 5-10 kts.
Thu...IFR cigs likely. Chc -RA. Wind NE 5-10 kts becoming NW.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&
$$
DISCUSSION...ETA
AVIATION...MPG
Area Forecast Discussion
National Weather Service Paducah KY
914 PM CST Sun Jan 21 2024
.KEY MESSAGES...
- A period of freezing rain appears likely across the Ozark
Foothills of southeast Missouri Monday morning and afternoon.
Elsewhere, temperatures largely rise above freezing before
the rain arrives.
- A significant warm up occurs this week along with multiple
rounds of rain Monday night through Thursday. Widespread
amounts of 1 to 3 inches are expected, but localized higher
totals are possible which could lead to a marginal flood risk.
&&
.UPDATE...
Issued at 915 PM CST Sun Jan 21 2024
00z HRRR and observational trends show a slightly faster onset
to precip than originally anticipated. Temperatures aloft are
fairly warm (increasing to 5C). Its going to be a relatively
warm rain falling into what will become pretty marginal
temperatures but dewpoints are still very low so wetbulb cooling
as the column saturates is a concern and may keep temps lower a
little longer. The antecedent ground conditions are obviously
very cold as well. Have a 4 inch frost depth here at Paducah
with road temperatures running 23-27 degrees so think the
opportunity for roadways impacts may be a little stronger than
the 30-31 degree temps imply. It`s a touch and go sort of
situation but did add a few counties to the eastern edge of the
winter wx advisory before the late evening news cycle.
&&
.DISCUSSION...
Issued at 251 PM CST Sun Jan 21 2024
Our extended stay in the ice-box is nearing it`s end thankfully. We
should finally rise above freezing across most of the region on
Monday, marking an end to our extended arctic outbreak. However,
there remains some concern that our Ozark Foothill counties of
southeast Missouri may struggle to go above freezing until late in
the day or even during the evening. If the ECMWF is to be believed
then they wouldn`t rise above until midnight or later, of course
this is a far outlier at this point. These really frigid airmasses
tend to struggle to leave, so a bit concerned we may have more icing
out that way as a result. For this reason have opted to issue a
Winter Weather Advisory for ice amounts of up to a tenth of an inch.
Further east there is some concern for a light icing across other
portions of southeast Missouri and southern Illinois, however it
appears the bulk of the precipitation holds off until late afternoon
or evening when temperatures should be above freezing in these areas.
The synoptic pattern this week will feature an upper level ridge
across the eastern U.S. and troughing across the southwest U.S. This
will lead to a moist southwest flow across our area until Thursday.
Waves of rain are expected across the TN and OH valleys through this
period. Timing and placement of the heaviest swaths still needs some
fine tuning. Will likely continue to have fluctuations in amounts,
but for now looks like widespread 1 to 3 inches across our cwa.
After a break on Friday, there are indications that another system
could impact the region with more rain next weekend.
The flooding concerns would be highest in areas that receive 2+
inches. However, amounts are expected to fall over a long enough
duration to largely prevent significant flooding issues. There is
some concern that the frozen ground may cause more runoff than
normal though. Certainly feel like there will be a good amount of
standing water in yards and low lying areas, ponding of water on
roads, etc. If thunderstorms end up producing localized higher
amounts up near or above 3" Wednesday into Thursday, then we may
have a bit more flooding to deal with.
Temperatures will be significantly warmer this week with highs in
the 50s to lower 60s Wednesday through Friday. A nice change
compared to this past week!
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 557 PM CST Sun Jan 21 2024
BKN-OVC200 clouds will drop to BKN-OVC050 from west to east
between 06z-12z. Chances of -RA at KCGI/KMVN after 18z,
possibly -FZRA at times. Winds will be from the southeast to
south at 6-12 kts.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Winter Weather Advisory from 6 AM to 6 PM CST Monday for
ILZ075-080-084.
MO...Winter Weather Advisory from 6 AM to 6 PM CST Monday for
MOZ076-086-100-107>109.
IN...None.
KY...None.
&&
$$
UPDATE...RST
DISCUSSION...JGG
AVIATION...RST
Area Forecast Discussion
National Weather Service Sacramento CA
236 PM PST Sun Jan 21 2024
.Synopsis...
An active weather pattern continues through Monday with periods
of rain, high-elevation snow and gusty wind.
&&
.Discussion...
The long anticipated final wave of this weekend weather system
will begin to impact the region later this afternoon, bringing the
heaviest precipitation tonight into Monday morning. As seen from
satellite and radar, the beginnings of this wave are beginning to
move into the CA coast. Time of arrival of this wave in the
Sacramento area is between 6-7pm PST, with heaviest rain expected
after 9-10pm PST. Storm total rain for the Valley locations hasn`t
changed much since the previous forecast, with the 36 hour totals
of 1-2 inches with up to 3-4 inches in the foothills and
mountains. Hires models indicate a fairly board swath of moderate
rainfall (0.25"-0.50"/hr rates) this evening potentially lasting
for several hours, which may warrant short-fused flood products to
highlight the flooding threats. Even so, if you encounter flooded
roadways, turn around don`t drown. It only takes 6 inches of
fast- moving water to sweep a car away.
Snow levels briefly went down to around 5,000 feet this morning,
allowing for a few inches of snow to accumulate, but snow levels
have since increased to around 6,000-6,500 feet per CCTV cameras
and observations, where they should remain through much of
tonight. Total snowfall forecast also had minimal changes since
the previous forecast, with around 8-16 inches above 6,500 feet
and up to 2 feet along mountain peaks. The Winter Storm Warning
remains through 10 pm Monday.
Outside of precipitation, winds have remained breezy across the
region, and will peak this evening-tonight with gusts across the
Valley reaching around 30-35 mph, with localized locations
potentially seeing gusts as high as 40 mph. Hires guidance is only
highlighting about a 20-40% of seeing gusts greater than 40 mph
this evening, and latest HRRR runs have generally trended downward.
If winds do reach marginal advisory criteria they are expected to
be brief, only lasting 1-3 hours. Given the short duration and
localized nature of marginal Wind Advisory level winds and
continued communication about the wind potential over the last
several days, decided to forego a wind headline, given the main
impacts are still expected to be those related to precipitation.
Widespread precipitation and gusty winds will diminish through
Monday morning-afternoon across the region, with lingering
precipitation across the foothills and mountains through Monday
evening.
With diminishing cloud cover Monday afternoon across much of the
Valley, hires guidance is indicating enough instability may
develop for some isolated thunderstorms to develop, potentially
bringing brief, heavy rain, gusty winds, and small hail. As the
upper-level lift quickly shifts eastward, the support for
thunderstorm develop will be limited to only a few hours late
tomorrow afternoon-early evening. Given this, shear will be
limited too, not anticipating the organization of any
thunderstorms, if they do develop.
By Tuesday morning, much of the precipitation chances will
diminish, leaving behind light winds and a very saturated ground.
If clouds move out quickly Monday night, fog development will be
likely across the Valley. Confidence is marginal on the extent and
density of the potential fog development Tuesday morning, given
the uncertainty in cloud cover that morning. Otherwise, much of
Tuesday is expected to be mostly dry, before another weak system
moves into the region late Tuesday night-Wednesday bringing
renewed rain chances. Rain on Wednesday is not expected to be
impactful, with storm total amounts of 0.10"-0.25" for much of the
Sacramento Valley. Higher rainfall totals are possible across
portions of the northern Sacramento Valley, where 0.50-0.75" are
possible, with locally higher amounts in the Shasta County
mountains. Snow levels will yet again be somewhat high, falling
in the 5,000-6,500 foot range. With limited precipitation, this
will only result in a couple of inches of snowfall (1-4").
//Peters
&&
.EXTENDED DISCUSSION (Thursday THROUGH Sunday)...
Ensembles depict upper-level ridging is expected to move over
Northern CA as a shortwave slides into the Great Basin area on
Thursday. This will help moderate rainfall conditions, however an
AR stretching into the Northwest Pacific glances over northwestern
CA. This will keep persistent precipitation chances over the
mountains and Northern Sacramento Valley through Saturday night
(25-50% chances). Confidence on amounts and timing is low, albeit
trending higher that aforementioned areas will receive some
precipitation late next week. Current probabilities show a 35-55%
chance of exceeding 0.50 over the mountains and Northern
Sacramento Valley Thursday through Saturday night.
Temperatures trend warmer with the rising heights, particularly
next weekend but will depend on cloud cover and developing
precipitation.
&&
.AVIATION...
Areas of MVFR/IFR with localized in next 24 hrs over Northern
California as a Pacific Storm passes through. Gusty south to west
winds 15-25 kts with localized gusts up to 35 kts possible through
Monday 18Z. Strongest winds will be 06Z Monday through 12Z
Monday. In areas of higher terrain, southwest winds gusts up 40
kts through 15Z Monday. Chances for isolated thunderstorms Monday
afternoon and evening in the Valley (15-25% chance) Snow levels
around 6000-7000 feet through Monday morning.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
Flood Watch through late Monday night for Central Sacramento
Valley-Motherlode-Mountains Southwestern Shasta County to
Western Colusa County-Northeast Foothills/Sacramento Valley-
Northern Sacramento Valley-Southern Sacramento Valley.
Winter Storm Warning until 10 PM PST Monday for West Slope
Northern Sierra Nevada-Western Plumas County/Lassen Park.
&&
$$