Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/30/22
Area Forecast Discussion
National Weather Service Denver/Boulder CO
844 PM MST Tue Nov 29 2022
.UPDATE...
Issued at 837 PM MST Tue Nov 29 2022
It`s much quieter across northeast Colorado compared to 24 hours
ago. A few clouds, and perhaps a couple of light snow showers, are
still located across some of the northern mountains, but should
continue to dissipate overnight. It`s clear across most of the
plains, though we`re starting to see some patchy fog develop over
portions of Larimer county. Have added just a touch of patchy fog
into Larimer/Weld counties where BUFKIT profiles suggest fog
development over the next few hours.
Otherwise, the only other notable change was to lower MinT`s
tonight, as a few spots in the river valleys have already dropped
below NBM 5th percentile values. I`m not sure we dropped them
enough, but a few more spots will certainly fall below zero. Did
ponder some Wind Chill Advisories, but it doesn`t look like we`ll
have enough areal coverage across any zone along the far
northeastern plains. Either way, it`s going to be chilly!
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 237 PM MST Tue Nov 29 2022
Current GOES-16 satellite imagery shows mid level water vapor over
the high country and weather station observations displays an
agreement of temperatures reaching forecasted afternoon highs. Snow
showers have begun tapering down overall but higher peaks will
continue to see flurries through late afternoon. Any additional
amounts will remain under an inch through this evening. 700mb
temperatures HRRR and NAM trending near -15 to -18 across the region
and it likely overnight lows will drop into the lower teens in the
urban corridor, single digits for the foothills and plains, and
several degrees below zero for the mountains and valleys.
Overnight into Wednesday morning, QG fields are showing strong
subsidence tonight meaning drier conditions. 500mb westerly winds
are increasing as latest guidance suggest 70-80kt winds. This
suggests a small mountain wave event for our foothills areas and
mountains where wind gusts up to 35-45 mph is possible through the
overnight hours. Thus, this forecast update includes an increase to
winds. Model soundings indicate an inversion in the urban corridor
should keep winds relatively weaker but would not be surprise if
parts of the urban corridor such as Broomfield, Superior, and
Arvada could receive gusts up to 35 mph briefly.
Wednesday, a slight warm up is possible with temperatures barely
above freezing for all areas above 10k ft and partly cloudy
skies.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 237 PM MST Tue Nov 29 2022
...BOUTS OF MOUNTAIN SNOW AND WINDY AT TIMES...
For Wednesday night and Thursday, southwest flow strengthens with
gusty winds developing over the mountains. Low temperatures on
Wednesday night will be a challenge, with sharp valley inversions
but sufficient drainage winds combining with warm advection in/near
the foothills and Palmer Divide. We cooled off the low spots a few
more degrees with sharper inversions, while warming up the
foothills/nearby plains a few more degrees from the existing
forecast. Wouldn`t be at all surprised to see more sharpening
needed as we head into the shorter term. For Thursday, a good
warmup is expected with the strong warm advection and 700 mb
temperatures rising to +3 to +5C across the plains. That would
normally support highs well into the 60s, but there will be some
lingering snow cover to offset especially along and north of the
I-76 Corridor. That`s where we`ll keep it somewhat cooler, but
again some sharpening in the forecast temperature gradient may be
required as get into the closer term and have more details
regarding snow cover and local wind patterns (expect a weak
cyclone or at least a shear zone north of the Palmer Divide
keeping it cooler to the north as well). South of that, it will
likely be warmer than forecast.
Our attention will then turn toward a rather potent shortwave
moving across the Great Basin and Northern/Central Rockies Friday.
While moisture increases late Thursday night and early Friday
morning with snow developing in the mountains, it may be late
Friday morning into Friday afternoon when significant impacts
arrive for high Country travel in the North Central Colorado
mountains and I-70/Summit County Corridor. That`s when strong
cold advection arrives and joins forces with improving (but still
westerly) orographics. The mid level flow is very strong with
mountain top flow greater than 50 knots, so any period of heavier
snow will likely produce significant travel impacts and blowing
snow. Snow squalls will even be possible with the arrival of the
mid level cold front/frontogenesis. We`ll also have to worry
about high wind potential across the higher mountains, foothills,
I-25 Corridor and portions of the plains. With 50+ knots at 700
mb, it won`t take much subsidence to get high winds spreading into
the lower elevations. Best subsidence at this time behind the
cold front stays just to our north, but something to watch
especially considering the magnitude of the flow. Gradients also
support near high wind forecasts.
After that system, there should be a period of relatively tranquil
weather Saturday before the next system arrives by late Sunday or
Monday. Right now, ensembles are offering up a bit more
troughiness with this shortwave, so a little better chance of some
snow spilling onto the plains toward Monday. However, mountains
are still most favored at this time for more accumulating snow and
travel impacts. Temperature forecasts will remain difficult
especially with rather strong warm advection between these fast
moving shortwaves. Slight timing difference (also common in these
fast moving progressive patterns) can also have large implications
on realized temperatures.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 440 PM MST Tue Nov 29 2022
VFR through the TAF period. Winds are fairly weak and will remain
light through tomorrow. Drainage flow is expected to establish
tonight, turning more north/northwesterly at DEN Wednesday
morning. Any lingering low clouds should diminish over the next
couple of hours with no ceiling or visibility concerns
anticipated.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Hiris
SHORT TERM...AD
LONG TERM...Barjenbruch
AVIATION...Hiris
Area Forecast Discussion
National Weather Service Columbia SC
829 PM EST Tue Nov 29 2022
.SYNOPSIS...
Showers and thunderstorms are expected across the area beginning
late tonight through Wednesday as a cold front crosses the
region. Rainfall amounts up to 1 inch possible and some gusty
winds. Cool and dry conditions finish out the week before a
warming pattern sets in for the weekend.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
Surface high pressure continues to retreat off the coast as a
strong storm system approaches from the west. Air mass remains
quite dry with PWATs around 0.5-0.7 inches but increasing
southwesterly low level flow ahead of an approaching upper
trough will rapidly increase the atmospheric moisture through
the overnight hours. Regional radar already showing some showers
pushing into the Upstate at this time. As these showers move
into the Midlands they may weaken initially as they encounter
the drier air but measurable rainfall is expected to arrive
shortly after midnight with the highest rain chances pushing in
as a convective line in the 10-12z time frame from the west.
Instability is extremely low so the severe weather threat is
also very low, however cannot rule out isolated thunderstorms.
Temperatures have cooled quickly after sunset with some
locations already approaching forecast lows so will need to
adjust them a bit but clouds are moving in from the west and
will stabilize temperatures for the remainder of the night. In
fact, as winds increase later tonight temps may rise a bit
through sunrise with better mixing and continued thickening
cloud cover. Expect lows in the low to mid 50s.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
Little change in the thinking for Wednesday`s cold front passage as
a line of showers and isolated thunderstorms moves through.
Synoptic forcing will generally remain to our north for much of
the day with limited jet level dynamics nor impactful mid-level
height falls. Instability will remain limited as strong warm
advection from 850mb through 700mb overruns weak surface flow
early Wednesday, along with the lack synoptic support aloft; the
hi-res and GEFS members at most produce 100 J/kg of sfc based
CAPE. So while both 0-1km & 0-6km layer shear are both strong
(30 & 60 knots respectively), much like our frontal passage on
this past Sunday, this will very likely be a highly over-sheared
event. There continues to be mixed solutions across the hi-res
guidance, with some rapidly strengthening convection to our
south and robbing moisture and others keeping a more
consolidated line. Regardless, there is consistent signaling in
both environmental soundings and convection depiction in a
limited severe threat that is further supported by limited
synoptics and diurnal timing. Best timing is mainly 12z thru 18z
with showers and isolated thunderstorms, with between 0.3-1.0"
of rainfall expected along with some gusty winds over 30 mph.
By Wednesday afternoon, winds will shift out of the west-
northwest with strong cold and dry advection behind the front.
Low temps will fall into the 30`s for much of the area.
Drier and cooler for Thursday as high pressure fills in. Winds
will turn from for the northwest to northeast and dew points
will fall into the 20`s with high temps staying capped out in
the 50`s. Low temps Thursday night will be the coldest of the
week, falling into the low 30`s and upper 20`s.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
Strong 1030+ mb surface high will exit off the east coast on
Friday, and there is excellent consensus in another calm, cool,
and dry day Friday. GEFS members bottom out PWAT`s around 0.2"
before moisture begins late Friday. With the high exiting off
the coast and weak southerly flow returning, NAEFS shows PWAT`s
steadily increasing throughout the weekend along with GEFS
members stalling a weak front across the area by Saturday. So
precip chances increase late Saturday and into Sunday. A warming
signal is still very evident in the long term into next week
with NAEFS pushing PWATS`s, heights, and temps all above the
90th percentile. So confidence is fairly high in a return to
above average temperatures by next week.
&&
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
VFR for the time being, but expectation is that restrictions will
quickly develop later tonight and into Wednesday as a strong front
approaches the region.
Southeasterly flow has developed across the forecast area today and
is leading to a slow but gradual increase in moisture across the
area. With dry air and high pressure still in place across the
region, I do expect VFR to last for the next few hours. Clouds
should quickly increase through 03z-05z and remain VFR as this
occurs, with a possible exception at OGB. Low-level flow is
southeasterly, and that usually favors stratus especially when skies
are clear. This looks most likely to be maintained at OGB for
several more hours with stratocumulus and cirrus being a bit further
west. HRRR and LAMP guidance has recently suggested that a brief
period of LIFR cigs are possible at OGB between 05z and 07z, but I
am hesitant to include that in the TAF at this time. From there, the
forecast is fairly simple, with moisture and rain increasing in
coverage from west to east quickly after 08z. Rain should generally
bring cigs/vis to MVFR (this is common in obs to our west) and I
expect that to be the case given we`re already in the warm sector of
this system. However, there should be embedded convection within
this rain, so expect IFR cig/vis to occur at times, and I cover that
in a TEMPO group at all sites. I don`t think there will be
widespread thunder & don`t include it in the TAF, but don`t be
surprised if there is some lightning with this. The heaviest
rain generally looks to occur from 09z to 17z across the
region, quickly pushing out of the area thereafter as dry air
pushes in. Look for LLWS to occur during this time as well. I do
think that some MVFR cigs will likely hang on for a couple
hours after the rain stops, but generally should be out of here
after 21z. Winds will start near the east or southeast this
evening, quickly shifting out of the south and southwest ahead
of the front.
EXTENDED AVIATION OUTLOOK...No restrictions expected late in the
week as dry air returns.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Charleston SC
1007 PM EST Tue Nov 29 2022
.SYNOPSIS...
High pressure will prevail through late tonight. A cold front
will move offshore Wednesday, followed by high pressure.
Another cold front could briefly stall over the area this
weekend.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
Cirrus clouds are expected to increase across the forecast area
this evening, sourced from upstream convection. Return flow is
expected to remain steady through the overnight hours. The
forecast will feature steady temperatures through the rest of
the evening, then gradual warming through daybreak. By sunrise,
temperatures may warm by 2-4 degrees above mid-evening values.
The mid-levels will consist of a strong trough over the north-
central Plains in the evening. It`ll take on a slightly negative
tilt as it moves over the Upper-Mid MS Valley overnight.
Additionally, the jet stream will be in the vicinity of this
feature. At the surface, low pressure over WI in the evening
will shift NNE into Canada overnight, dragging with it a strong
cold front. The front is expected to cross over the Appalachians
late at night, with hints of a warm front developing to our
north. Moisture will increase ahead of the front, with PWATs
exceeding 1.25" late. The combination of the moisture, lift from
the front, and lift in the mid/upper levels will generate a
line of showers along/ahead of the front. Clouds will gradually
increase this evening and overnight. The models have come into
better agreement with the start timing of the showers. If
anything, the trend has been ever so slightly slower with the
arrival. So we have rainfree conditions most of the night, with
slight chance to chance POPs very late far inland, where the
stronger forcing and deeper moisture will be. Temperatures will
fall into the 50s overnight, but should level off or start
rising again late as the surface winds become more SE to S and
clouds increase.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
Wednesday: A strong shortwave embedded in the polar jet will
dig across the Ohio Valley as a 514dam upper low propagates
across southern Ontario. This shortwave will help drive a cold
front across the Southeast U.S. as high pressure slides farther
offshore of the Eastern Seaboard. Low-level moisture return
ahead of the cold front will be slow to occur with most of the
guidance only showing a ribbon of PWATs >1" and an axis of deep,
vertically consistent moisture being confined to along and just
ahead of the wind shift. The strongest Q-G forcing is forecast
to remain displaced well to north within the region of modest
DCVA ahead of the shortwave as it shears out of the Ohio Valley,
but model cross sections show a narrow, but strong corridor of
deep-layered UVVs passing through just ahead of the front,
likely owing to low-level forcing with the front itself and some
contribution from the tail end of the right entrance region of
a subtropical jet streak. This will support a fairly large
frontal rain band, which will likely be in a weakening phase as
it approaches the coast due to some thinning of the ribbon of
deep-layered moisture and increasing mixed-layer stability. All
ensemble members are showing some degree of measurable rainfall
during the morning into the afternoon even as the band weakens
as it approaches the coast. Pop were raised to 70-90% with QPF
amounts ~0.10-0.50 inches as a result. Rain chances will quickly
end by early evening as the front pushes offshore and a drier
post-frontal airmass settles in. Although shear modest shear
will be in place in the warm sector, very limited instability
will negate the overall severe potential as the situation does
not look favorable for a late fall high shear/low CAPE severe
event. SPC removed the marginal risk from South Carolina and
much of Southeast Georgia from the 29/17z Day 2 WFO guidance
outlook.
Highs will be closely tied to high quickly rain moves in from
the west. Areas near the CSRA and southern Midlands may struggle
to reach 70 before the onset of rain while areas to the east
may have sufficient time to warm into the lower-mid 70s. A
general blend was used to construct Wednesday`s highs. Lows
Wednesday night will range from the upper 30s/lower 40s well
inland to around 50 at the beaches.
Thursday and Friday: Quiet and dry conditions will prevail
during this time as high pressure extends across the region.
Highs will warm into the upper 50s/lower 60s Thursday then
recover to the mid- upper 60s for Friday. Lows Thursday night
will drop into the mid- upper 30s well inland to the lower 50s
at the beaches.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Mostly quiet conditions will dominate for much of the extended
period as the region is forecast to remain along the northern
periphery of a large mid-level subtropical anticyclone centered
over the Gulf of Mexico. An isolated shower or two could occur
near the coast by Friday as weak coastal trough tries to develop
just offshore, but confidence is not high enough to justify a
mentionable pop just yet. A cold front could briefly stall over
parts of the Southeast U.S. this weekend before lifting back to
the north as a warm front. Uncertainties in the degree of
moisture return and where the front stalls support keeping
mentionable pops out of the forecast for now. Above normal
temperatures can be expected.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
Conditions across KCHS/KJZI/KSAV are expected to remain VFR
through the overnight hours. A band of pre-frontal convection is
expected to near the terminals during the first couple of hours
of daylight Wednesday morning. Latest run of the HRRR and HREF
indicate that the band of showers will push across the terminals
between 14-18Z with gusty SW winds, highlighted with TEMPOs. In
the wake of the showers, ceilings are expected to lower into
MVFR across KCHS/KJZI with periods of IFR at KSAV, generally
after 18Z.
Extended Aviation Outlook: The risk for showers will end Wednesday
afternoon. Otherwise, there are no concerns.
&&
.MARINE...
Tonight: High pressure will move off the coast of the
Northeastern U.S. while a cold front approaches from our west.
This will cause winds to veer to the SE this evening, then S by
daybreak Wednesday. Additionally, winds will be sustained
around 10 kt in the evening, increasing to around 15 kt late.
Seas will respond by building to 2-3 ft.
Wednesday through Sunday: The main concern for this period
centers on Wednesday night into Thursday. There will be a risk
for Small Craft Advisory conditions during this time as north to
northeast winds initiate during a period of post-frontal cold
air advection followed by a pinching of the pressure gradient
with high pressure centered to the north. Winds could reach as
high as 20-25 kt with gusts to 30 kt for all coastal legs with
conditions in the Charleston Harbor reaching 15-20 kt. Seas will
build to 4-6 ft nearshore waters and 5-7 ft over the Georgia
offshore leg. Conditions in the Charleston Harbor could fall
just short of advisory levels, but this will need to be watched.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.
&&
$$
NEAR TERM...NED
SHORT TERM...
LONG TERM...
AVIATION...NED
MARINE...
Area Forecast Discussion
National Weather Service Grand Rapids MI
945 PM EST Tue Nov 29 2022
LATEST UPDATE...
Update
.UPDATE...
Issued at 945 PM EST Tue Nov 29 2022
Cold front is knocking on the door and there has been a few tstms
across WI/IL within the line of showers preceding the front. Most
of the storms are now restricted to nrn Lk MI, but really can`t
rule out a rumble of thunder anywhere as that band of showers
crosses the area over the next few hours.
Wind gusts associated with the showers have only been around
30-35 kts, although some higher gusts have been noted back behind
the cold front. The Wind Advisory is somewhat marginal since the
narrow cold frontal rain band isn`t doing much and the highest
winds are not expected until Wednesday afternoon, but will make
no changes at this time.
Temperatures have warmed into the mid to upper 50s this evening
just ahead of the front, but will be near freezing by the morning
commute. Current thinking is that travel for the morning commute
should be okay since road temps are currently 45-50 and it will
take some time to bring those down. Plus the lake effect snow
showers do not get going in earnest until after 9 or 10 am.
&&
.DISCUSSION...(This evening through next Tuesday)
Issued at 323 PM EST Tue Nov 29 2022
- High Winds / Rain showers to Lake Effect Snow
The surface low has developed as expected from the digging 160
knot jet core from British Columbia dug into the base of the upper
trough over western CONUS. It is now being driven by a 130 knot
jet core and will race northeast across wester Lake Superior
later this evening, exiting into central Ontario Wednesday.
This drives a strong cold front through here around midnight. 850
temperatures fall around 16c in 12 hours, which is significantly
more than any cold front we have had in the past 3 months. The
front that brought us all the snow only had a 12c drop in 12
hours, which was similar to the cold front that came through here
on September 22nd. Another way to look at that is at 2 pm there
was a 25 degree temperature drop from eastern to western Iowa.
So, what this means for us, since gulf moisture is starting to
stream into the system on the warm side of it, and area of showers
and thunderstorms has already developed from Southern Illinois
southward. The northern edge of that will quickly develop
northward. We should see showers in our area by sunset or shortly
after that. A narrow frontal rain band is forecast by the high res
models just in front of the cold front over our area. This will
be in the 11 pm (MKG) to 2 am (JXN) time frame. Winds may gust
into the 40 to 50 mph range as this convective band moves through
our area. The instability is marginal at best for thunderstorms
here, but it is not out of the question. Actually through the
gusty winds will happen with the convective line whether there is
or is not thunder.
Due to the strong pressure gradient that will increase this
evening, surface wind will be gusty. We issued a wind advisory
from 10 pm until 8 pm Wednesday. The 10 pm to 2 am time range was
to cover wind gusts with the convective line on the cold front.
Once the cold front comes the showers will come to an end.
Winds will shift to the west northwest while temperatures fall
from the lower to mid 50s at midnight to the mid 30s by 3 am.
As the core of the coldest air moves in, wind gusts will increase
into the 40 to 45 mph range by late morning or early afternoon.
The highest wind gusts are expected between 2 pm and 6 pm
Wednesday.
As for snow with this system, the trusty rule of being on the
cyclonic side of the polar jet will work great in this event.
Just about all of the high resolution models go in that direction
but the HRRR seems to this time have a better handle on the snow
showers activity than does the NAMNEST. The HRRR shows inversion
heights reaching near 8000 ft while the NAM only shows around 5000
ft. Given how deep and wrapped up this system is and how much
cold air trails it, I am going with the HRRR snow forecast. This
gives us narrow band of strong snow showers that extend west to
east across most of southern Lower Michigan from mid morning till
early evening. Most locations should see only a dusting to an inch
but some location just east of US-131, north of Kalamazoo through
Reed City could see over 2 inches. With winds of 20 to 30 mph
gusting 40 to 50 mph and temperatures during the day light hour
mostly in the upper 20s to lower 30s, this will cause some local
travel issues. There may be morning and more so, evening drive
time travel issued due the combination of the gusty winds, snow
and blowing snow.
- Quiet Weather Returns by Thursday
The back edge of upper cold pool moves east of our area by early
Thursday morning. That will end the snow showers and calm the
winds down too. Shortwave ridging between the system departing the
area and the next upstream Pacific system will provide dry weather
for most of Thursday and all of Friday. It will warm up again too,
highs should be well up int the 40s by Friday once again.
- Two more system to impact our weather
The system over the weekend has a lot of variance in the models,
both model to model and run to run with the same model. One way or
the other this too will have a decent amount of wind with it as
there is a 135 knot jet core associated with it. This will mean
rain showers to snow showers Saturday into Sunday. At this time
the system is moisture starved. Do not expect much precipitation
with this storm.
-Then the cold air really comes back
The next system ,that comes through in the Tuesday to Wednesday
time frame, has had some continuity issues in the models. Even so,
most of the ensemble members of the GFS and Ecmwf keep the cold
air in place once it gets hear. That is because a large blocking
upper high develops near Greenland. This is a classic upper high
location if one wants cold weather in Michigan. It`s expect rain
showers to snow showers with this system too.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 710 PM EST Tue Nov 29 2022
Winds are the main aviation impact over the next 24 hours. This
evening we have southeast winds gusting up to 30 knots which
switch to the southwest overnight then west by daybreak
Wednesday, increasing through the day.
The winds on Wednesday will gust as high as 40 kts at times in
the afternoon, but there may also be a brief period of 40 kt
gusts with the band of showers which comes in from the west later
this evening. This narrow cold frontal rain band could even have a
tstm or two embedded in it.
As far as the ceilings and vsbys, the current VFR conditions will
trend into the MVFR category by 03Z or so, then some brief IFR
cigs/vsbys will be possible for about an hour as that band of
rain showers and isolated storms moves through. Conditions
predominately MVFR on Wednesday as snow showers develop, although
occasional IFR/LIFR vsbys are possible under any heavier snow
showers which develop.
&&
.MARINE...
Issued at 219 PM EST Tue Nov 29 2022
Our gale warning now runs from 7 pm until 4 am on Thursday.
The strongest winds will be after the cold front comes through
midnight once the cold air comes in to mix the stronger winds
down. The winds are expected to remain strong into early evening
Wednesday. The peak winds are expected to be during the mid to
late afternoon.
Winds will quickly diminish between mid morning Thursday into mid
afternoon. Then our next system will repeat the cycle of south
winds increasing to near gale force Friday, then the cold air
comes in Saturday so strong winds will continue into later
Saturday.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Wind Advisory until 8 PM EST Wednesday for MIZ037>040-043>046-
050>052-056>059-064>067-071>074.
LM...Gale Warning until 4 AM EST Thursday for LMZ844>849.
&&
$$
UPDATE...Meade
DISCUSSION...WDM
AVIATION...Meade
MARINE...WDM
Area Forecast Discussion
National Weather Service Lincoln IL
713 PM CST Tue Nov 29 2022
.SYNOPSIS...
Issued at 321 PM CST Tue Nov 29 2022
Gusty southerly winds will continue into this evening ahead of a
cold front that will quickly move through central and southeast
Illinois. Showers and a few storms are expected to develop along
the front this evening, while isolated severe wind gusts may be
associated with the showers and storms, primarily east of I-55.
Much colder temperatures, gusty west winds, and dry conditions
are expected for Wednesday. Precipitation chances return from
Sunday into early next week.
&&
.UPDATE...
Issued at 710 PM CST Tue Nov 29 2022
As of 7 pm this evening, a cold front is moving east across I-55
and is expected to exit central Illinois into Indiana between
10pm and midnight tonight. Scattered showers and isolated storms
have been in place along and ahead of the front but should quickly
end once winds turn northwesterly. While winds have mostly come
up just shy of reaching advisory criteria (gusts of 45 mph),
several sites have been very close ahead of the front, and
earlier obs from DVN and MLI did show gusts in excess of 45 mph
immediately behind the front right as winds veered to westerly.
Will let the wind advisory ride for the remainder of central/east
central Illinois this evening. In terms of the severe threat, some
of the shower have exhibited weak, transient rotation. 00Z ILX
sounding did not indicate any notable instability, but surface dew
points have been creeping up across east central Illinois,
especially near and south of I-70, and RAP continues to indicate
the potential for a little over 100 J/kg MLCAPE just ahead of the
front. Will have to continue to monitor closely but the weak
instability and storms struggling to maintain stronger updrafts
should keep the severe threat it check. Finally, temperatures fall
quickly behind the front, dipping near or below freezing within
about 2 to 3 hours of frontal passage. Any lingering wet spots on
roads could freeze and result in slippery conditions, particularly
on elevated surfaces such as bridges and overpasses.
&&
.SHORT TERM...(This evening through Wednesday)
ISSUED AT 321 PM CST Tue Nov 29 2022
Light showers did develop in southeast IL this afternoon but have
quickly moved off into IN. The forecasted cold front is on the
doorstep of IL and will quickly move through the CWA this evening,
reaching GBG by 5 pm, I-55 by 7 pm, I-57 by 9 pm, and then out of
the state between 10 and 11 pm. Intense showers are expected to
develop along the front in the next hour or 2 and then quickly
move northeast while the front move to the east. Gradient winds
ahead of the front will remain gusty with gusts of 40-45 mph
possible at times. Strong dynamics along the front and strong low
level winds could allow some storms, especially east of I-55, to
produce some isolated damaging wind gusts this evening. Winds
behind the front will be gusty as well, still possibly reaching up
to 40 to 45 mph. Hence, the wind advisory will continue. Most of
the area will be dry by midnight, but some light precip is
possible in the far southeast just after midnight. As evident on
the sfc maps and seeing the tight temp gradient, temps will
plummet behind the front. This could lead to some possible icy
spots and residual moisture from the showers will likely quickly
freeze in spots before the wind evaporates it.
Temps will quickly drop this evening and through the night. Temps
overnight will be below 30 degrees. Gusty winds tonight will bring
about single digit to low teen wind chills overnight. Wed high
temps will likely only climb about 10 degrees to the lower 30s to
near 40. Skies will be mostly sunny tomorrow, however, northwest
winds will be gusty again and daytime wind chills will remain in
the teens.
.LONG TERM...(Wednesday night through Tuesday)
ISSUED AT 321 PM CST Tue Nov 29 2022
Dry conditions are expected the rest of the week and into most of
the weekend. The next weather system will arrive Sunday with
chances of precipitation, which will continue into the beginning
of next week. Far enough out and plenty of differences in the
models, so p-type will just be rain, snow or a mix of rain and
snow.
Temps through the extended will be a roller coaster, with cold
temps for one day and then warming back to around normal for 1-2
days, then cooler again over the weekend, then warming again at
the start of next week...enjoy.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 527 PM CST Tue Nov 29 2022
A strong cold front is sweeping across central Illinois this
evening. Variable MVFR/VFR conditions and strong southerly winds
gusting to around 30 kt will continue ahead of the front, then
will veer to the NW behind the front with MVFR ceilings becoming
more prevalent. A brief line of showers is expected with the
front, and an isolated storm cannot be ruled out.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 9 PM CST this evening for ILZ031-037-038-
041>043-048-051>053.
Wind Advisory until midnight CST tonight for ILZ044>046-054>057-
061>063-066>068-071>073.
&&
$$
UPDATE...Deubelbeiss
SYNOPSIS...Auten
SHORT TERM...Auten
LONG TERM...Auten
AVIATION...Deubelbeiss
Forecast Discussion: Over the long term, battle continues between
Gulf ridge and cold intrusions out of Canada. Upper trough moves
across the northern U.S. Friday through Sunday. Next trough drops a
bit deeper into the Plains and Great Lakes early next week.
High pressure settles over the area Thursday with below normal
nighttime temperatures expected Wednesday night and Thursday night.
The first trough spins up a strong surface low over the Plains
Friday and drives it northeast into the Canadian maritimes through
the weekend. That will push a weak cold front through here Saturday
morning. Gusty winds and some rain is likely with the front Friday
night and Saturday. Southwest flow will drive moist air and above
into the area Monday. This will set the stage for what could be a
couple day rainfall event as a warm front sets up nearby starting
Sunday and continuing into the early next week. Another cold front
moves through the area later Tuesday with colder air/below normal
temperatures behind it.
&&
.Aviation...(00Z TAF Issuance)
Issued at 639 PM EST Tue Nov 29 2022
IMPACTS:
-Gusty winds through tonight, including LLWS roughly WS020/19050KT
-Widespread showers and storms this evening into the overnight
-MVFR ceilings/visibility at times; possible IFR in strongest storms
DISCUSSION:
Low pressure system still on track to impact area terminals with
gusty southerly winds, thunderstorms, and MVFR ceilings and
visibility this evening into the overnight hours. IFR conditions
are also possible in the strongest of storms. Low level wind shear
will also be an impact around 2K feet from the south around
40-50kts, ending by 6z. By daybreak, VFR conditions should return
as the front passes by late Wednesday morning with skies clearing
and WNW winds through Wednesday evening.
CONFIDENCE:
Medium on all elements.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Mesoscale...RAS
Short Term...CG
Long Term...KJF
Aviation...MK
Area Forecast Discussion
National Weather Service Midland/Odessa TX
520 PM CST Tue Nov 29 2022
...New AVIATION...
.SHORT TERM...
(This afternoon through Wednesday night)
Issued at 204 PM CST Tue Nov 29 2022
500mb RAP initialization shows the upper trough centered across
Colorado this afternoon. Its associated jet max passing overhead
is contributing to a very windy day across the region. The
strongest winds remain out west across the Guadalupe and Davis
Mountains where a High Wind Warning remains in effect through late
this evening. Strong winds have found their way into the Permian
Basin as well, prompting an expansion of the Wind Advisory through
north-central Lea County and the northwestern Permian Basin. As
the jet max departs and diurnal mixing subsides after sunset,
winds will come back down to more modest levels.
After a mild day with high temperatures reaching the mid 70s for
most thanks to downsloping westerly winds, high pressure building
southeastward through the central Plains will push a cold front
through overnight. Temperatures will tumble back below freezing
north of I-20 with lows in the 30s and 40s to the south. High
temperatures tomorrow will be 10-15 degrees below average behind
the front with east-northeasterly winds, topping out in the 40s
north of I-20 and the 50s and 60s to the south. Northerly flow
behind the front will be short lived as the high pressure center
moves into the Mississippi Valley and southeasterly winds return
Wednesday night. Lows will be a little bit warmer as a result,
with freezing temperatures limited to the far northern zones and
the higher elevations.
-Munyan
&&
.LONG TERM...
(Thursday through Monday)
Issued at 204 PM CST Tue Nov 29 2022
Zonal flow is expected across the United States through at least
early next week. This westerly flow will favor warm, downsloping
winds keeping temperatures near to above normal. A series of upper
level troughs will develop and move east within the flow but will
remain well north of our CWA. Normally this means little chance
for rainfall, however the arrival of a cold front on Saturday will
coincide with Pacific moisture and a strengthening jet stream to
give a chance of rain from southeastern New Mexico to the Permian
Basin. Rain chances will continue into Saturday night before drier
air arrives Sunday.
&&
.AVIATION...
(00Z TAFS)
Issued at 502 PM CST Tue Nov 29 2022
Winds across the plains are starting to decrease and by 01Z should
be below 12kts at all TAF sites. Cold front still n of LBB as is
generally expected to be HOB/MAF 04Z-05Z, INK about 06Z. By 12Z
winds will light, then e-se Wed. Low-level water imagery shows
wave action across/downstream of mtns as such light low flying
aircraft can expect severe turbulence INVOF mtns into the evening.
&&
.PRELIMINARY POINT TEMPS/POPS...
Big Spring 73 31 50 36 / 0 0 0 0
Carlsbad 70 32 49 32 / 0 0 0 0
Dryden 81 39 56 39 / 0 0 0 0
Fort Stockton 76 35 56 38 / 0 0 0 0
Guadalupe Pass 62 34 47 34 / 0 0 0 0
Hobbs 66 27 48 32 / 0 0 0 0
Marfa 69 31 60 30 / 0 0 0 0
Midland Intl Airport 73 31 51 37 / 0 0 0 0
Odessa 72 32 51 37 / 0 0 0 0
Wink 73 31 52 36 / 0 0 0 0
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
TX...High Wind Warning until 10 PM CST /9 PM MST/ this evening for
Guadalupe Mountains Above 7000 Feet-Guadalupe and Delaware
Mountains.
Wind Advisory until 7 PM CST this evening for Davis Mountains
Foothills-Eastern Culberson County.
High Wind Warning until 7 PM CST this evening for Davis
Mountains.
NM...High Wind Warning until 9 PM MST this evening for Guadalupe
Mountains of Eddy County.
Wind Advisory until 6 PM MST this evening for Eddy County Plains.
&&
$$
Area Forecast Discussion
National Weather Service Morristown TN
935 PM EST Tue Nov 29 2022
...New UPDATE...
.UPDATE...
Issued at 922 PM EST Tue Nov 29 2022
Current forecast still looks reasonable. Portions of the southern
half of the area are approaching or have already exceeded an inch
of rain. Hi res models generally indicate a break in the steadier
rain soon, and radar is trending that way at the moment. With
some additional moderate to heavy rainfall expected, will need to
continue to monitor for localized flooding issues. So far have not
seen any observations higher than 42 mph in the mountains, but
highest winds expected a bit later. Will leave the wind warning as
is for now. No significant changes planned with this update.
&&
.SHORT TERM...
(This evening through Wednesday)
Issued at 306 PM EST Tue Nov 29 2022
Key Messages:
1. Showers and thunderstorms tonight, especially south of Interstate
40 with storm total rainfall around 2". Isolated flooding possible
in locations with multiple rounds of heavy rainfall.
2. High wind warning for gusty winds in the foothills and high winds
in the east Tennessee mountains late tonight through the overnight.
Discussion:
A large upper trough is currently situated in the central CONUS,
with GOES visible satellite showing anvil blowoff from ongoing
elevated convection west of us beginning to reach near our Plateau
counties. SPC HREF guidance brings these storms and showers to the
Plateau counties by 00z. Rain and thunderstorms will then continue
for most of the night, with the cold front arriving tomorrow morning
to clear the rainy weather out.
GFS has an interesting double jet structure in association with the
upper trough, with a polar jet rounding out the trough, and a
subtropical jet coming out of Texas. SPC currently has a slight risk
just west of our most southwest portion of the with the plateau
counties and anyone west of Knoxville in a marginal risk for severe
wind. The main headlines from a severe weather perspective all
remain to our west in Alabama and Mississippi. Meanwhile over here
CAM guidance maintains a potent low level inversion for most of the
night concurrent with the best dynamics aloft, so while we cannot
rule out severe weather, it`s not expected. Definitely expecting
thunderstorms though, which will give us some periods of heavy
rainfall, especially the southernmost border counties along Georgia.
Cannot rule out isolated flooding in our southernmost counties, with
guidance showing a couple rounds of heavy storms moving through
Alabama and Georgia through southern Tennessee.
Late tonight as the surface trough quickly moves northeast to our
northwest, the 850 mb jet strengthens across the area. 850mb flow
from the south to southeast across the Smokies will develop
overnight. This, combined with a tight pressure gradient along the
mountain range will produce gusty downsloping winds along the east
Tennessee mountains into the foothills. NAM and HRRR cross sections
back the general idea up, with strong omega values indicative of
downward vertical motions along the Smokies. The current NPW looks
to be in good shape with no updates planned.
By Wednesday morning the rain and storms will be on their way out,
in advance of the incoming cold front. Front will sweep across the
area in the morning hours, taking our mild temperatures out with it.
Post frontal winds could be a bit breezy, so altogether a not so
pleasant day. Afternoon temperatures tomorrow will be much cooler
&&
.LONG TERM...
(Wednesday night through next Tuesday)
Issued at 306 PM EST Tue Nov 29 2022
Key Messages:
1. Below normal temperatures Thursday then gradually warming through
the remainder of the extended period.
2. Chance of rain showers returns this weekend and into early next
week.
Discussion:
Longwave troughing across the Eastern CONUS will gradually lift to
the northeast on Thursday with upper ridging beginning to build in.
At the surface, we continue to have a very cold, dry airmass with
high pressure centered over the region. This will keep temperatures
below normal on Thursday with a sunny, clear sky. By Thursday night
and Friday, surface high pressure will shift to the east with return
southwesterly boundary layer flow allowing for a gradual increase in
temperatures and an increase in clouds due to weak isentropic lift.
A strong shortwave trough is forecast to move eastward across the
Great Lakes on Saturday with an associated surface low. There will
be a trailing cold front to the southwest across the Ohio Valley and
Mississippi Valley. As this front moves east on Saturday, scattered
rain showers are expected across the region. With limited moisture
return, QPF is forecast to remain low, generally a one-quarter inch
or less.
We expect to have a brief dry period on Sunday as the front becomes
stationary just to our south across MS/AL/GA. Sunday night into
Monday, this front is forecast to move back northward as
southwesterly 850mb flow increases ahead of shortwave troughing
across the Great Plains. An area of rain showers is expected along
and north of this front as it lifts northward on Monday with
strongest boundary layer convergence and PoPs to our west.
&&
.AVIATION...
(00Z TAFS)
Issued at 607 PM EST Tue Nov 29 2022
Will see showers and some thunder around at times overnight, with
thunder most likely at CHA. Cigs/vsby will drop to MVFR at times
in heavier precipitation, and will likely become predominantly
MVFR later tonight. There may be at least brief IFR conditions,
but timing uncertainty as well as lower probability means it will
be left out for now except for a tempo at CHA. The low level jet
will be strong for a period tonight, and if surface winds are
lighter than expected LLWS may occur. Conditions will quickly
trend VFR as precip ends and clouds scatter out Wednesday morning.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 50 62 31 50 / 100 30 0 0
Knoxville McGhee Tyson Airport, TN 50 61 28 49 / 100 40 0 0
Oak Ridge, TN 47 61 28 48 / 100 40 0 0
Tri Cities Airport, TN 49 59 25 46 / 100 60 0 0
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...High Wind Warning until 10 AM EST Wednesday for Blount Smoky
Mountains-Cocke Smoky Mountains-Johnson-Sevier Smoky
Mountains-Southeast Carter-Southeast Greene-Southeast
Monroe-Unicoi.
VA...NONE.
&&
$$
SHORT TERM...Wellington
LONG TERM....JB
AVIATION...