Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/14/20
Area Forecast Discussion
National Weather Service La Crosse WI
646 PM CST Mon Jan 13 2020
.UPDATE...
Issued at 639 PM CST Mon Jan 13 2020
The winter weather advisory has been expanded to cover the
remainder of the forecast area. The RAP has been consistent
through the late afternoon and early evening of showing the
potential for freezing drizzle to occur behind the snow band.
Forecast soundings show a loss of ice in the clouds occurring
quickly behind the snow while the lower portion of the sounding
remains saturated with plenty of lift occurring through this
saturated layer. Already seeing some reports of freezing drizzle
upstream across southeast South Dakota and northwest Iowa. To
further complicate things, fog is also occurring with the freezing
drizzle with visibilities under two miles at times. With
temperatures remaining below freezing tonight, this could also add
a some light riming to the mix. With the combination of snow,
freezing drizzle and fog expected to create slippery to hazardous
driving conditions, felt a winter weather advisory was the best
route to go. If the RAP is correct, parts of the area could still
have a potential for freezing drizzle to occur into early Tuesday
morning and the advisory may have to be extended in time if this
is the case.
&&
.SHORT TERM...(Tonight through Tuesday)
Issued at 153 PM CST Mon Jan 13 2020
Eyes are on fairly potent mid-level wave moving into the central
Plain from the Rockies this afternoon per latest GOES water vapor.
This wave will spin up surface cyclogenesis over western MN this
evening with a strong push of 925-700mb isentropic lift into our
area. Rap shows strong omega in the saturated -12 to -18C range
dendritic growth zone. Looks like this strongest lift will be during
the evening hours, then pushing east of the area after midnight.
Also of note will be the potential/likelihood for loss of ice in
cloud as the snow tapers off. So, could see a hour or two period
of some light freezing drizzle. Right now, looks like the highest
snow totals tonight (2-3+ inches) will be from portions of
northeast IA/ southeast MN into west-central and northwest WI.
Lesser amounts of a dusting to 2 inches can be expected across the
rest of the forecast area.
Models indicating nice push of drier air into the area Tuesday
behind the departing wave of low pressure and incoming ridge of high
pressure from the Plains. This should act to scour out stratus from
west to east by afternoon.
.LONG TERM...(Tuesday night through Monday)
Issued at 153 PM CST Mon Jan 13 2020
Winter weather fans, rejoice! After the recent mild weather, this is
your week to enjoy some more typical January conditions, with
several additional risks for snowfall expected through the weekend.
The overall pattern the next 7 days looks to retain a bit of a
Pacific-influenced/zonal look, with periodic shortwaves
traversing the region and linking up with sufficient colder air to
deliver occasional wintry precipitation chances. After tonight`s
bout of snow, the next risk looks to come later Tuesday night into
Wednesday morning as the next shortwave quickly works through the
region. Pretty solid axis of deep layer QG-upward forcing and low
level warm advection ascent should have little trouble saturating
an initially dry atmosphere, and much like recent events, can`t
rule out a little freezing drizzle at the tail end Wednesday
as deeper moisture scours out. However, this system is a fast
mover, with decent forcing but limited residence time for any one
location, suggesting more of a 1-2 inch event for most, perhaps a
little higher toward central Wisconsin with some hint of a better
frontogenetic axis bisecting the Highway 29 corridor.
Synoptic forcing quickly dwindles later Wednesday, though may
still contend with some flurries as sharp low level cold advection
pushes whatever residual stratus remains well into the dendritic
growth zone. Otherwise, the Wednesday night-Thursday period looks
quiet but rather chilly as cold Canadian high pressure slides
through the region, with highs on Thursday likely only in the
single digits and low teens and overnight lows near or below zero
pending cloud trends.
Looking even farther out, the Friday-Saturday period remains of high
interest with increasing consensus for a stronger upper trough to
work through the region. Still some spread among ensemble members
with regard to the track of the surface-700mb lows (most are south
of the local area), but deeper moisture from an open Gulf of Mexico
and slower advertised movement of that feature suggests at least a
risk for higher snowfall totals. Again, plenty of details to be
worked out, but this one bears close watching, with little weather
of note expected from Sunday into Monday as another round of colder
high pressure builds south into the area.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 504 PM CST Mon Jan 13 2020
A challenging forecast from a precipitation type standpoint. A
short wave trough will move across the region overnight providing
plenty of forcing for precipitation production. Expect
precipitation from this system to spread over both airports this
evening with conditions going down to IFR in snow. Forecast
soundings from the RAP late this afternoon suggest there is a
relatively short 2 to 3 hour window for the snow before ice aloft
is lost in the clouds which should make the dominant precipitation
type freezing drizzle. Observations downstream across eastern
South Dakota and Nebraska already confirm the presence of the
freezing drizzle along with fog. Based on this and the forecast
soundings, will maintain the IFR conditions into early Tuesday
morning for both freezing drizzle and fog. As the winds swing
around to the west, dry air will start to work in that will first
shut off the precipitation production and fog and then allow the
clouds to scatter out in the late morning/early afternoon.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory until 6 AM CST Tuesday for WIZ017-029-
032>034-041>044-053>055-061.
MN...Winter Weather Advisory until 6 AM CST Tuesday for MNZ079-
086>088-094>096.
IA...Winter Weather Advisory until 6 AM CST Tuesday for IAZ008>011-
018-019-029-030.
&&
$$
UPDATE...04
SHORT TERM...DAS
LONG TERM...Lawrence
AVIATION...04
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
607 PM EST Mon Jan 13 2020
.AVIATION...
Low level moisture will be trapped through the TAF period, with the
only debate being whether we are looking at IFR vs MVFR cigs.
Cooling boundary layer this evening leading to MVFR cigs, followed
by modest surface/near surface moisture increase tonight should lead
to cigs falling at and below 1000 Feet, with the higher confidence
across the northern TAF sites. Cigs look to struggle to rise much
during tomorrow until the wind shifts to the southwest, but even
then likely only rising into LOW MVFR.
Light and variable winds this evening with surface high pressure in
place. The high will drift east, allowing winds to become southeast
late tonight into tomorrow morning, but still probably under 10
knots. A wind shift to southwest and an increase in winds will then
occur in the mid afternoon with a surface trough passage. The low
level convergence with this trough could be enough to touch off some
light drizzle.
DTW THRESHOLD PROBABILITIES...
* High for ceilings at or below 5000 ft through the taf period.
* Low for light drizzle 10-17Z Tuesday.
&&
.PREV DISCUSSION...
Issued at 328 PM EST Mon Jan 13 2020
DISCUSSION...
High frequency shortwave pattern will continue to impact Southeast
Michigan through midweek as quasi-zonal flow remains in place. No
shortage of shortwaves ejecting out of and under the parent closed
upper level PV anomaly over British Columbia.
Shortwave ridging in tow of early day absolute vorticity
maximum/shortwave will support lowering subsidence during the
remainder of the afternoon. Earlier this morning, mixing depths were
just high enough at 6.0 kft agl to allow for some perplexing ice
nucleation and some rogue light snow shower activity near and along
I 96. Since then there has been less evidence of observed
precipitation with skies here at the office become increasingly
brighter. This lends increased confidence in the lowering inversion
which should at least help in thinning out the stratus overcast.
Colleagues point out that boundary layer thermal vortices, swirling
out over the Great Lake basins, are causing some disruption to the
stratus field with clearing at midlake. This points to very thin
cloud field/potential for ascent and will remove any mention of
flurries for the remainder of the afternoon and evening.
The next shortwave is scheduled to lift northward and pivot into
negative tilt across the Central Great Lakes by 12Z Tuesday.
Certainly a respectable structure to the shortwave and what at first
glance appears to be some decent warm advection. System relative
isentropic analysis shows a very brief duration of system relative
isentropic ascent between 12-15Z. The biggest negative factor for
the event is the real struggle for any meaningful deep saturation.
Models show a tangible ribbon of 850-725mb equivalent potential
temperature dragging across Southeast Michigan. However, forecast
soundings tell the story that saturation is virtually non-existent
in the 3.0-6.0 kft agl layer. The nam is the most bullish, while the
RAP struggles and the ECMWF has been very consistent with no QPF.
The bottom line is the best case ceiling for this event is for a
trace or hundredth of liquid. Did maintain a chance of drizzle for
forecast continuity, with surface temperatures at/above freezing.
Late Tuesday and Wednesday the upper level flow over North America
is expected to become split flow with the northern stream over
Wisconsin and Michigan. Models continue to advertise some phasing of
the two streams over the central part of the country with coupled
jet dynamics resulting in a wave of low pressure through Michigan.
Models show a coherent, deep low pressure center tracking through
central Wisconsin Wednesday afternoon with a wing of warm advection
lifting into the state. There are difference with how the models
handle the system. The ECMWF is much more phased and developed,
while the NAM maintains separation between the northern and southern
stream trajectories/moisture. Regardless, what is of higher
confidence is the lack of true cold air advection in advance of the
low which supports a rain/mix across the cwa and temperatures will
be balmy possibly ranging middle 30s north of middle 40s south. Will
continue to go with a chance/likely of rain and snow across the cwa.
The fail point to the forecast and something to monitor is what the
trends become of how phased the system is. A more developed cyclone
will result in greater cold side deformation and minor snow
accumulations clipping the northern cwa, primarily Wednesday evening.
High amplitude ridging and arctic high pressure is forecasted to
build into the region Thursday and Friday. Temperatures will cool
down with the +1045mb arctic high but the lack of snow cover will
temper conditions.
MARINE...
A weak low pressure system will pass over the northern Great Lakes
Tuesday which will cause southeast winds to ramp up a bit during the
day. Air will be relatively warm which will limit gust potential to
around 25 knots with the best chance of the highest gusts coming in
the evening immediately behind a cold front. There is a brief
opportunity for waves to reach 4 feet along the nearshore waters
near the tip of the Thumb with the sustained along shore flow for
several hours but appears too brief to issue a Small Craft Advisory
at this time.
Another stronger low will then track across the southern Great Lakes
Wednesday into Wednesday night. Increased northwest flow will usher
in a colder airmass which will lead to unstable conditions over the
waters for Thursday. Gust may reach 30 knots building wave heights
and increased mixing depths may result in snow squalls as well.
Large area of high pressure then arrives Thursday night into Friday,
assuring lighter winds (under 20 knots) but still cold and
potentially light snow showers lingering into Friday morning.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&
$$
AVIATION.....SF
DISCUSSION...CB
MARINE.......DRK
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
950 PM CST Mon Jan 13 2020
...Short Term Update...
.UPDATE...
Issued at 949 PM CST Mon Jan 13 2020
..Dense Fog Advisory Counties Adjusted a Bit..
Ah, the joys of forecasting/nowcasting fog and dense fog when it`s
not a "completely straightforward" situation. Based on automated
airport obs from Smith Center KS (K82) along with calls to county
dispatch/law enforcement, was compelled to add
Webster/Smith/Osborne to the Dense Fog Advisory, as dense fog
issues crept a bit farther west into those counties than earlier
anticipated, and seems to be very-much-tied to the fringes of the
stubborn lingering stratus deck in that area. Meanwhile, opted to
"ditch" Nance/Merrick from the Advisory (and probably could have
let go of a few other northeast counties as well), as frankly
there has been little sign of dense fog formation thus far in
that area, which will also be transitioning to more of a westerly
breeze in the next few hours, making more than brief/fleeting
dense fog fairly unlikely. As Dense Fog Advisories go, this one is
struggling to amount to much for MOST of the issuance area, but
again, there have been enough reports of dense fog in some of our
southern counties to at least justify the existence of the
headline in the first place. As outlined earlier, any fog/dense
fog should scour out of our CWA from west-to-east well before
sunrise.
UPDATE Issued at 657 PM CST Mon Jan 13 2020
..Dense Fog Advisory Issued For Eastern CWA through 3 AM..
In collaboration with OAX/TOP/ICT, we have issued a Dense Fog
Advisory valid until 3 AM for all 11 of our counties east of the
Highway 281 corridor. To be fair, this is not a multiple-hour
"can`t see your hand in front of your face" situation for most of
the Advisory area, but based on visibility progs from the
HRRR/RAP, the majority of the Advisory area appears favorable to
see at least a few hours of visibility near-to-below 1/4 mile at
some point tonight (already evident at Hebron airport).
Fortunately, drier low-level air gradually advecting in behind
the passing surface trough will scour out fog/low clouds from
west-northwest to east-southeast as the night wears on. In fact,
overnight shift may be able to cancel a few of the northern
counties (such as Nance/Merrick/Hamilton) a few hours early, while
our far southeast (Thayer/Mitchell) could hold onto dense fog
right up until the currently-slated 3 AM expiration.
On one last note, we probably cannot rule out some patchy/brief
dense fog just west of the official Advisory area (Hwy 281
corridor counties) as this is where the back edge of the low cloud
deck currently resides. As a result, have issued an SPS to cover
the more fleeting nature of any possible dense fog in these
counties.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 239 PM CST Mon Jan 13 2020
Aloft: WV imagery and RAP tropopause analyses indicated low-
amplitude SW flow was over the Cntrl Plns within basically zonal
flow. A wk shrtwv trof was over WY/CO/NM. This trof will lift NE
and cross NEB/KS this evening. Heights will rise a bit in its
wake...leaving W-WSW winds thru tomorrow. Another wk shrtwv trof
will move onshore in the W tomorrow.
Surface: 1029 mb high pres was over the OH Vly while the main
polar front was stationary from the GtLks acrs SD into MT. Wk 1008
mb low pres was over WY. This low will move E along the front
tonight. It will drag a sfc trof thru the CWA followed briefly by
1020 mb high pres. Low pres will begin forming over CO tomorrow.
Rest of this afternoon: Skies are partly-mostly sunny over
Furnas/Gosper counties. This should spread N and E as the shrtwv
trof departs. So expect gradually dcrsg clds...espcly W of Hwy
281. E of Hwy 281 is another issue. As always...low stratus and
fog during the day are a big fcst problem and that is the lowest
confidence portion of this fcst. Mdls don`t handle it well and so
we really are winging it as it when improvement might occur.
Tonight: Believe we will eventually see improvement/clearing of
the low stratus over most of the CWA. Some low-lvl WAA will occur
with the passage of the sfc trof late this afternoon/evening. This
should shove whatever low stratus is left E of the CWA.
However...this stratus has suppressed daytime temps...leaving them
perilously close to the dwpt and near saturation. So with
clearing and light winds...fog expect should easily redevelop E of
Hwy 281...and espcly along Hwy 81. It may not last all the way
thru the night. Even the fog-heavy NAM indicates improvement late
tonight as drier air/dwpts drift in.
Tue: Sunny and mild. Just about everywhere should reach the 40s.
Probably the warmest day of the next 7. A very nice day with light
winds.
.LONG TERM...(Tuesday night through Monday)
Issued at 239 PM CST Mon Jan 13 2020
Aloft: The last 2 runs of the GFS-FV3/EC/CMC/UKMET are tightly-
clustered on some moderate amplification of the longwaves...but
with the flow remaining progressive. Admittedly...this is not how
we envisioned last week at this time. It looked as though the PNA
pattern would turn negative and remain negative for the
foreseeable future. Zonal flow will cont into Wed. The wk Wrn USA
shrtwv trof mentioned above will cross NEB/SD late Tue night into
Wed AM. Upstream amplification over the N Pac will result in
formation of a new trof off the W coast. This will force a ridge
to build over the Wrn USA Wed night. This ridge will cross NEB/KS
Thu followed by SW flow until the E Pac trof crosses the rgn which
will be Fri. The progression of the flow is then fcst to slow or
halt altogether as the Aleutian low dvlps...with a downstream
ridge building over the Wrn USA/Can. So once the Fri trof moves
by... increasingly amplified NW flow is fcst over NEB/KS.
Surface: The wk CO low that forms Tue will head ENE acrs KS Tue
night. This low will yank the stationary front (currently over SD)
S thru the CWA Wed morning...with strong high pres nosing S from
Wrn Can. This 1045 mb high is fcst to slide into the Nrn Plns Thu
and into ON/QB Fri. Meanwhile...low pres will form over CO and
emerge into KS Fri...with a warm front lifting N to near I-70.
This low will deepen on its way into the GtLks Sat with Canadian
high pres nosing in here. It appears that the Arctic front will
move into NEB/KS and become stationary from NW-SE...parallel to
the flow aloft Sun-Mon.
Temps: will average near normal. Thu will probably be the coldest
day of the next 7.
Once we get into NW flow...that typically keeps the CWA on the SW
fringe of the Arctic air...with wild swings in temps. Brief
intrusions of Arctic air will alternate with downslope-warmed air
about every 2-3 days.
Precip: The only event currently envisioned is Thu night into Fri.
The last 2 runs of the GFS-FV3/EC/CMC are in remarkable agreement
for this far out. Most of the precip should fall over the E 1/2 of
the CWA with 0.10-0.25". Probably less than 0.10 W of Hwy 281.
It`s a little early to get into specifics about ptype...but both
the 12Z EC/GFS indicate potential for a slight warm nose. So we
could be looking at a light wintry mix of SN/IP...possibly mixed
with -FZRA. The depth of the sfc-based cold air will be the key.
Based on how it looks now...this looks like a solid advisory-
level event...espcly with the Fri AM commute potentially impacted.
Stay tuned for more details as this is still 78 hrs away.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Tuesday)
Issued at 657 PM CST Mon Jan 13 2020
General overview:
The majority of the period is actually a fairly high-confidence
VFR forecast (especially for KEAR). However, KGRI currently
resides near the far western edge of a pesky low stratus deck
(IFR/MVFR), which will likely linger for at least a few more hours
before departing eastward. Both sites (but again especially KGRI)
could see at least a few hours of fairly light fog this evening,
with MVFR visibility ongoing at KGRI. Although VFR
ceiling/visibility is expected to return to KGRI within the next
3-5 hours, attention then turns to a brief period of low level
wind shear (LLWS), which has been introduced to both sites from
05-08Z. Read on for more wind-related details...
Winds (including LLWS):
Starting with surface winds, light breezes tonight (under 10KT)
will gradually turn from southerly to westerly behind a passing
surface trough, then become light/variable direction Tuesday
morning before becoming steadier from the southeast in the
afternoon (around 10KT). As for the LLWS 05-08Z, this was
introduced to account for a passing corridor of west-northwesterly
30-35KT winds within (roughly) the lowest 1,000 ft. above the
surface. The net result will be somewhat marginal (albeit
mentionable) shear magnitude of around 30KT between the surface
and this level.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...Dense Fog Advisory until 3 AM CST Tuesday for NEZ049-063-064-076-
077-085>087.
KS...Dense Fog Advisory until 3 AM CST Tuesday for KSZ006-007-018-019.
&&
$$
UPDATE...Pfannkuch
SHORT TERM...Kelley
LONG TERM...Kelley
AVIATION...Pfannkuch
Area Forecast Discussion
National Weather Service Houston/Galveston TX
946 PM CST Mon Jan 13 2020
.NEAR TERM [Rest of Tonight]...
Went ahead and pulled the trigger for a Dense Fog Advisory for all
of SE TX tonight (previously, just along the coast). Conditions do
remain favorable for the continued development of fog overnight in
to tomorrow morning. Of note...some of the latest short models are
indicating that the lower visibilities could persist well into the
afternoon. But for now, will keep the expiration time for this fog
advisory for inland locations at 10 AM...with sea fog likely ling-
ering over the bays/nearshore waters all day. 41
&&
.PREV DISCUSSION... /Issued 400 PM CST Mon Jan 13 2020/...
SHORT TERM (Tonight and Tuesday)...
A warm front lies just off the Upper Texas Coast and this feature
is serving as a focus for showers and isolated thunderstorms.
Much warmer air is poised to enter SE TX and temperatures tonight
will remain nearly steady or perhaps slowly rise as the warm front
moves north. Warm and moist air will flow over the cooler shelf waters
and periods of sea fog will develop and will likely affect coastal
communities and a Dense Fog advisory may be required later tonight.
In addition to the fog, warm air advection will also produce periods
of light rain or drizzle. All in all, tonight will be a murky damp mess.
Late tonight or early Tuesday, the GFS, HiRes ARW and the 18z HRRR all
show convergence increasing along the US 59 corridor. Omega also
increases significantly and precip will likely expand in coverage and
increase in intensity prior to sunrise. Will be carrying likely PoPs
for much of the area and will include thunder as fcst soundings show PW
values near 1.80 inches and K index values in the upper 30`s. Mid level
lapse rates look less than today but sufficient to generate thunder. It
should be warmer than today but have some concerns that precip and
extensive cloud cover will keep temps a little cooler than the blends
would suggest. 43
LONG TERM (Tuesday night through Monday)...
Upper ridging laid across the Gulf will ultimately control our
weather pattern through a cold frontal passage on Saturday,
There will be a series of weak disturbances (enhanced PVA) that
will stream across Central Texas within the mean westerly steering
flow and provide just enough lift to maintain subsequent day
(mainly far interior) low to moderate POPS for showers and
isolated thunderstorms. The main story for this upcoming work week
is still the unseasonably warm and humid conditions as the
eastern Texas remains entrenched under a stout onshore flow
regime.
Nocturnal fog will remain an issue throughout the week especially
over the nearshore Gulf and local Bay waters and surrounding
communities. Low overcast with periods of sea and inland fog
lowering visibilites from around 5-6 SM to under a mile will
likely occur but just too difficult to pin point timing of onset.
So, best to monitor and react as the soup thickens up with short
fuse fog advisories. Precipitation will be very light, mist to
light showers through the remainder of the work week.
A cold front is forecast to cross southeast Texas sometime on
Saturday during the day. POPs will increase to high moderate over
the central and southern forecast area ahead of the front through
Saturday. As of now, higher precipitation probabilities for low
QPF. North winds kick in later Saturday and will veer easterly
through early next work week. The passage of a shallow 5H trough
on Monday will again pick rain chances back up but, again, it will
be 20-30% chance for periodic showers/isolated storms this time
next week. 31
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 58 72 65 77 64 / 50 50 20 30 20
Houston (IAH) 60 76 67 78 66 / 50 60 10 20 20
Galveston (GLS) 62 70 66 72 65 / 30 40 10 10 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Dense Fog Advisory until 10 AM CST Tuesday for the following
zones: Chambers...Coastal Brazoria...Coastal Galveston...
Coastal Harris...Coastal Jackson...Coastal Matagorda...
Galveston Island and Bolivar Peninsula...Inland Brazoria...
Inland Galveston...Inland Jackson...Inland Matagorda.
GM...Dense Fog Advisory until noon CST Tuesday for the following
zones: Coastal waters from Freeport to Matagorda Ship
Channel TX out 20 NM...Coastal waters from High Island to
Freeport TX out 20 NM...Galveston Bay...Matagorda Bay.
&&
$$
Area Forecast Discussion
National Weather Service Lincoln IL
839 PM CST Mon Jan 13 2020
.SYNOPSIS...
Issued at 245 PM CST Mon Jan 13 2020
Cloudy skies with temperatures in the mid 30s to lower 40s were
the general conditions on Monday. Conditions will remain cloudy
overnight, with Tuesday morning lows in the upper 20s to mid 30s.
&&
.UPDATE...
Issued at 834 PM CST Mon Jan 13 2020
Mid evening satellite imagery shows rapid erosion of the stratus
from the southeast spreading northwest across central Illinois.
Low clouds have cleared east of I-57 and the clearing is expected
to continue to work towards the I-55 corridor over the next two
to three hours. It remains uncertain how much longer this will
continue, but RAP and HRRR low level RH fields seems to have a
decent handle on near term trends. They do show stratus
redeveloping from the south/southwest after midnight, though
likely not as widespread as what was occurring earlier. Overnight
temperature trends and possible fog development are the main areas
of concern with impacts from cloud cover or lack thereof
overnight. Relied heavily on RAP/HRRR hourly temp trends dropping
temps a few degrees in the east with non-diurnal trends after
midnight as cloud cover redevelops.
&&
.SHORT TERM...(This evening through Tuesday)
ISSUED AT 245 PM CST Mon Jan 13 2020
Strong low level inversion seen in morning sounding will continue
to keep moisture trapped and so overcast conditions to continue
overnight into Tuesday.
Moisture channel imagery shows weak upper wave moving over NE-KS
will continue to track over northern portion of IL. This will
bring slight chance of light rain to the extreme northern parts of
CWA tonight. Pcpn will be minor though.
A weak high pressure area will drift across Il on Tuesday, as the
next system forms in the west.
.LONG TERM...(Tuesday night through Monday)
ISSUED AT 245 PM CST Mon Jan 13 2020
For Tuesday night, the second short wave in the fast upper flow
over the midwest, will move toward IL, with some light pcpn again
developing in the overrunning pattern toward Wednesday morning.
With temps around freezing, some light freezing pcpn will be
possible in the northwest parts of the CWA Wednesday morning,
before changing to all rain. Rainfall amounts will be light
Wednesday, as the moisture is limited and this wave again moves
through quickly.
High pressure will be in control through Thursday. By late
Thursday night, a major shortwave with a deepening surface low
will be exiting the Rockies, with overrunning pcpn moving into IL,
starting on Friday and continuing into Saturday.
This system is a major one, but the models differ on the track,
amount of cold air, and moisture. For that reason, will message
that a system is expected, with the pcpn will start out as snow
Friday, and change over to rain in the south and central sections.
Is too early to mention amounts of snow, but will highlight
uncertainties, and that the system will be significant. The
northern third of CWA will have the best chances for the highest
accumulations. Heavy rain will also be a problem, especially over
areas where flooding was a result of the previous weekends
rainfall. Will have to watch amounts over region, as they may make
more flooding possible.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 527 PM CST Mon Jan 13 2020
A weak warm front will lift across central Illinois again late
this evening and overnight. Southeast winds ahead of the front
will veer to the southwest with passage of the front. Anticipate
lowering ceilings as the front approaches to IFR or LIFR along
with some possible fog, though have low confidence in how thick or
widespread fog will become. Should see modest improvement with
ceilings and a lower fog threat behind the front, though don`t
expect VFR conditions returning through the period.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Deubelbeiss
SYNOPSIS...Goetsch
SHORT TERM...Goetsch
LONG TERM...Goetsch
AVIATION...Deubelbeiss
Area Forecast Discussion
National Weather Service Paducah KY
956 PM CST Mon Jan 13 2020
.UPDATE...
Issued at 956 PM CST Mon Jan 13 2020
Have updated the forecast to catch up to satellite and METAR
trends. Skies have cleared over the northwest portions of the
region and temperatures have already fallen farther than expected.
Winds are also light and variable. All this has resulted in near
saturation and some light/MVFR fog development. Threw in some
patchy to areas of fog over the northwest half of the area, but
did not mention dense fog at this time. Just don`t have enough
confidence in the sky forecast at this time. Blended in the cooler
HRRR temperatures and dewpoints with the existing grids through
the overnight hours. Ended up with a stronger gradient from
southeast to northwest across the area.
As for the precipitation chances, it should be limited to the far
southeast corner of the area, where an elevated thunderstorm
cannot be ruled out. No change to the thunder forecast, but did
shave off the northwest edge of the PoP area.
UPDATE Issued at 543 PM CST Mon Jan 13 2020
The AVIATION section has been updated for the 00Z TAF issuance.
&&
.SHORT TERM...(Tonight through Wednesday night)
Issued at 100 PM CST Mon Jan 13 2020
Some breaks in the low clouds have finally formed over west KY.
The models suggest they may redevelop tonight. Will carry
considerable cloudiness, as high pressure moves east. We will
carry a chance of rain over the SE 1/3 of the area, primarily west
KY overnight, with even a slight chance of thunder just north of
the TN state line. This area should move off to the east early
Tuesday morning. Next rain chances moves in late Tuesday night and
continues Wednesday as low pressure tracks from Missouri to the
Ohio Valley region. Coverage should be scattered, with a slight
chance of thunder southern portions of the area. Dry Weather
returns Wednesday night as high pressure builds in. Temperatures
will be above normal.
.LONG TERM...(Thursday through Monday)
Issued at 100 PM CST Mon Jan 13 2020
Dry weather will prevail Thursday and Thursday evening. After
midnight, there is a chance of precipitation into Missouri,
possibly to the MS River. Tricky temperature forecast and thermal
profile. So we`ll have to monitor for a possible light wintry mix
at the onset of this next round of precip. However, if you believe
the EC/CMC solutions, there will be nothing to be concerned with,
no precip advertised til Friday. Otherwise rain chances increase
Friday, peak Friday night, end early Saturday. Decent rainfall
amounts possible, over 1 inch not out of the question. Dry weather
returns for later Saturday through Monday as high pressure builds
back in. Above normal temperatures through Saturday will return
to near normal Sunday through Monday.
&&
.AVIATION...
Issued at 543 PM CST Mon Jan 13 2020
MVFR ceilings have all but left the area, but much of the
available guidance is not aware of it. Definitely went on the
optimistic side of guidance and kept the area mostly VFR through
the period. A band of MVFR ceilings may work into southeast
Missouri and southern Illinois in the morning before scattering
out. Some light rain may work into west Kentucky late tonight, but
it is not likely to reach KPAH or KOWB. There should be an
increase in lower VFR clouds over much of the area overnight, but
MVFR or lower ceilings should stay southeast of the TAF sites.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
UPDATE...DRS
AVIATION...DRS
Area Forecast Discussion
National Weather Service Riverton WY
403 PM MST Mon Jan 13 2020
.SHORT TERM...(This evening through Tuesday night)
Will continue with the Winter Weather Advisory through 00Z
Wednesday for western portions of the forecast area. The short
term models including the HRRR model are similar in depicting a
quick increase in snow tonight across the western portions of the
forecast area to the west of the Continental Divide. Some mountain
locations will likely have amounts closing in on a foot through
Tuesday afternoon, but will stay with a Winter Weather Advisory
due to expected amounts. The short wave at 500 millibars is
progged by the short term models to shift eastward into the
central portion of the area by after 18Z Tuesday. There will also
be some scattered light snow expected across southwest through
southern sections of Wyoming between 18Z Tuesday through 00Z
Wednesday.
Elsewhere, it will remain dry on Tuesday, with brisk to windy
conditions expected from KRKS, extending northeast to KCPR. A
trailing surface cold front should move through the forecast area
by 00Z Wednesday. It will still be colder Tuesday night across a
good portion of the area in the wake of the cold front with temps
expected to be about 3-5 degrees colder for overnight lows by 12Z
Wednesday.
.LONG TERM...(Wednesday through Monday) Issued at 320 PM MST Mon
Jan 13 2020
Wednesday the west finally gets a break and the state will be
mostly dry. Unfortunately, isolated to scattered PoPs will quickly
return Thursday, increasing on Friday. A trough will move into the
area, bringing with it more snow across the west and south. Areas
to the north and east may also see some snow from this system on
Friday. Isolated light snow will linger in the northwest on
Saturday and Sunday, but otherwise most of the area should remain
dry. Winds will be gusty in the mountains each afternoon this week
and breezy to windy across southern WY. Temperatures will slowly
warm through the end of the week and then drop a few degrees again
just in time for the weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 352 PM MST Mon Jan 13 2020
West of the Divide...KBPI/KJAC/KPNA/KRKS Terminals
Light snow will continue to drift across the area for the rest of
this afternoon, but mainly MVFR and low VFR conditions will
prevail. Snowfall will begin to increase again shortly after dark
as a new system moves in. After 00Z, cigs will lower and vsby
will drop at KJAC/KPNA/KBPI for the rest of the night tonight.
Mountains will be frequently obscured. The heaviest snow, lowest
cigs, and vsby will occur after midnight tonight. Conditions will
improve somewhat at these locations by Tuesday afternoon. KRKS
and KJAC are likely to have some blowing snow due to gusty winds
that will decrease around sunset this evening. Winds will pick up
once again at KJAC and KRKS Tuesday.
East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals
Windy at KCPR and KCOD through the period. Other sites will see
their winds decrease again this evening. VFR conditions will
occur at the terminal sites through the period. Snow will occur
over the Wind River and Absaroka mountains with lower ceilings and
some mountain obscuration.
Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for
the latest information on icing and turbulence forecasts.
&&
.FIRE WEATHER...
Issued AT 305 PM MST Mon Jan 13 2020
Snow will linger in the west today and increase again tonight
with another wave. Snow will last until Tuesday afternoon with
occasional burst of heavier snow with snow showers. Areas east of
the Divide will be mostly dry. Winds, excluding in the basins,
have been strong at times with gusts 45 to 55 mph. Winds will
decrease overnight, but increase again Tuesday afternoon.
&&
.RIW WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 8 PM this evening to 5 PM MST
Tuesday for WYZ001-012>014-023>025.
&&
$$
SHORT TERM...Troutman
LONG TERM...Bourque
AVIATION...Lipson
FIRE WEATHER...Bourque
Area Forecast Discussion
National Weather Service Topeka KS
542 PM CST Mon Jan 13 2020
.UPDATE...
Issued at 542 PM CST Mon Jan 13 2020
Dense fog has already developed along the NEB state line. Forecast
soundings show the boundary layer becoming decoupled through the
overnight with light and variable winds. With snow melt adding to
the boundary layer moisture across the area, think the fog will
only expand south and east overnight. Will be working on a dense
fog advisory for the entire forecast area and hope to have it out
shortly.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 338 PM CST Mon Jan 13 2020
This afternoon, high pressure is positioned over the Ohio River
Valley with low pressure noted in the Front Range of the Colorado
Rockies. This setup is allowing for strong southerly low level flow
and WAA across the area. The above freezing temperatures have been
chipping away at snow pack across eastern KS, which could be seen on
visible satellite imagery where stratus had eroded over the eastern
CWA. The stratus is expected to fill back in as a shortwave
approaches the area from the west later this afternoon. Lift
associated with the wave, combined with a nearly saturated column
through about 5000 ft, as indicated by RAP and HRRR forecast
soundings, should be enough to allow for sprinkles/light rain for a
brief time as the wave moves over this evening. Into tonight, winds
will subside and a weak front will move through the area. Fog is
expected to develop again tonight due to moist grounds following the
weekend`s winter storm, and light winds. Models are showing a drying
of the low levels tomorrow morning, which should finally allow for
more widespread sunshine across the forecast area. Highs tomorrow
are expected to reach the low 40s north to near 50 degrees in our
southern counties.
.LONG TERM...(Tuesday night through Monday)
Issued at 338 PM CST Mon Jan 13 2020
A surface low will strengthen in the Front Range late tomorrow and
eject into the Plains early Wednesday. That low looks to work across
KS and into MO by sunrise Wednesday. Forecast soundings are showing
weak lift and a lack of deep moisture with this system so I am going
with a dry forecast for now. CAA will occur through the day
Wednesday in the wake of the low, so a standard diurnal warming
trend may not be realized during the afternoon. Thus, temperatures
will likely remain in the 30s and low 40s most of the day. A 1048mb
surface high will then slide out of Canada and settle over the
Midwest on Thursday. This will allow for some much cooler weather.
Temps in the AM could be in the single digits and low teens before
only warming into the 20s to near freezing during the afternoon.
The next system of interest will be moving onshore over the western
US Thursday, and will approach the region on Friday. Theta-e
advection will occur ahead of the wave late Thursday and early
Friday. As the system approaches, large scale ascent will occur and
precip will become likely area-wide by very early Friday. Surface
temps in the AM should be below freezing with the cooler airmass
still in place, but soundings are showing a slight warm layer
between 850mb and 750mb. This would lead to mixed precip in the form
of sleet/freezing rain before temps warm to above freezing later in
the morning. Total QPF is currently forecast to range from 0.50" to
1.0" across the CWA. This system will be one to watch through the
week for the possibility of winter weather early followed by a
decent rain event. Drier conditions are then expected through the
weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday)
Issued at 542 PM CST Mon Jan 13 2020
LIFR conditions are expected to develop with forecast soundings
decoupling the boundary layer and snow melt adding to the boundary
layer moisture. Think dense fog and should expand south and east
through the night, eventually breaking up during the late morning
Tuesday.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Wolters
SHORT TERM...Teefey
LONG TERM...Teefey
AVIATION...Wolters