Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/22/20

Area Forecast Discussion...UPDATED

National Weather Service Columbia SC

 656 PM EST Sat Nov 21 2020

.SYNOPSIS...
High pressure will keep dry weather over the region through
Sunday. Warming trend continues this weekend. A series of cold
fronts expected to cross the region early into the middle of
next week.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Upper high centered just to our SE, with surface ridge axis
across our region, providing fair weather and light winds. Late
tonight, the upper ridge will shift east with upper trough
approaching from the west. Models indicate a surface trough
developing offshore with some isentropic lift commencing. This
may spread some stratocumulus into our southern FA late tonight.
Some high level cloudiness may stream in from the west late
tonight as well. Patchy fog potential in areas where skies
remain mostly clear.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY NIGHT/...
Upper ridge axis shifts offshore Sunday with an approaching upper
trough and lowering 500mb heights over the area. The model show
an increasing low level onshore flow into the eastern portion
of SC. There will be deeper mid/upper level moisture in
increasing sw flow aloft. PWATs will increase to around an inch.
Coastal trough may lead to a slight chance of showers late
Sunday into sunday night, mainly in the eastern area but a lack
of significant forcing will limit shower coverage. Model time
sections show plenty of cloud cover Sunday into early Monday and
this will trend temperatures downward slightly from the recent
unseasonably warm temperatures. Cold front moves through late
Sunday night, keeping chances of showers in the east where
moisture will be higher with a cooler, drier airmass moving in
behind the front. Clouds through most of the night and mixed
boundary layer will keep lows in the upper 40s and low 50s.

High pressure will ridge southward into the region on Monday
through Tuesday. This will produce clear skies and pleasant
temperatures with a slight cool down Monday into Tuesday. More
favorable radiational cooling conditions Monday night, although
a weak low level jet will keep lows in the upper 30s to around
40 degrees across the area. As high pressure builds offshore
Tuesday night low level flow will become more east/southeast and
moisture will gradually begin to increase over the area. Expect
slightly milder temperatures Tuesday night with lows from 40 to
45 across the area.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Amplified pattern will remain in place. Another upper ridge
begins to slide off the coast Tuesday night into Wednesday as
deep trough ejects from the Four Corners region and lifts
northeast and closes off across the Midwest through Wednesday.
Associated surface low pressure and cold front expected to move
into the region Wednesday night into Thursday. Both ECMWF/GFS in
decent agreement that front will push through the region, but
have a difficult time pushing southward. As flow remains
zonal/southwest behind the front. Have continued with chance
pops with the associated front Wednesday night into Thursday.
Temperatures will likely remain slightly above normal through
the end of the week. Differences begin to appear in the models
as the weekend approaches. Models indicate a major system trying
to develop across the southwest portion of the country and head
eastward by the weekend into early next week.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
VFR conditions expected through 06z or so but then possible
restrictions in fog through the predawn hours.

Surface high pressure continues to prevail over the region but
low level moisture continues to slowly increase with the
southeasterly surface winds off the Atlantic. Winds will be near
calm overnight with mostly clear skies although some patchy
cirrus moving in from the west does complicate the forecast a
bit.

Mixed signals again in the guidance with HRRR and MAV/LAV not
really showing much fog but the MET guidance is hitting it hard
again with IFR/LIFR vsbys and our local radiational fog scheme
is also hinting at possible IFR vsbys around 12z. Also late
tonight the southeasterly flow will allow a weak surface trough
along the coast to move inland and bring some stratocumulus
clouds after 10z. Given the uncertainty in clouds but also
understanding little change in air mass other than some
increased low level moisture, will bring in MVFR vsbys at 09z at
CAE/CUB with tempo IFR vsbys through 12z. Introduce fog a bit
earlier at AGS given proximity to the river and dewpoint
depressions already at 6 degrees. Less confidence at OGB so only
carrying a tempo group there.

Vsbys should improve by 13z back to VFR and some VFR cigs
expected to spread over the region with weak isentropic lift
associated with the weak surface trough. Possibly some MVFR cigs
at OGB/AGS/DNL during the day but confidence is low.


EXTENDED AVIATION OUTLOOK...Restrictions in late night/early
morning fog/stratus possible through Tuesday.

&&

.HYDROLOGY...
Minor flooding continues along the shoreline of Lake Wateree.
Area reservoir operators continue to move water through the
Catawba/Wateree basin and expect the lake level to remain above
flood stage tonight and fall below flood stage on Sunday.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.

&&

$$




Area Forecast Discussion

National Weather Service Green Bay WI

 506 PM CST Sat Nov 21 2020

Updated aviation portion for 00Z TAF issuance

.SYNOPSIS...
Issued at 225 PM CST Sat Nov 21 2020

A light mix of precipitation across mainly north-central and
central Wisconsin tomorrow, with a more substantial round of
precipitation (much of it wintry) likely Tuesday into Tuesday
night.

The upper flow across North America was initially fairly flat. The
pattern will be slowly progressive and gradually gain amplitude
during the upcoming work week. There will also be a trend toward
increased splitting of the westerlies, at least at times.

The pattern will result in two substantial shortwaves crossing
the region, likely resulting in AOA normal amounts for the period.
Daily temperature departures from normal will be modest, though
generally on the above normal side of the ledger.
&&

.SHORT TERM...Tonight and Sunday
Issued at 225 PM CST Sat Nov 21 2020

The latest RAP analysis and satellite/radar imagery show high
pressure centered over the western Great Lakes early this
afternoon. Patches of clouds below 2000 ft lingered through much
of the morning over northwest WI and parts of north-central WI,
but is only slowly eroding early this afternoon. Looking
upstream, the next storm system is moving into the Dakotas. As
this storm system moves into the region, light precip chances are
the main forecast concern through Sunday afternoon.

Tonight...High pressure will gradually shift to the east, but will
continue to have plenty of influence on our sensible weather. The
evening should be clear and calm for most locations. Mid and high
clouds will increase from west to east after midnight, but
forecast soundings indicate that the layer below 10 kft will
remain dry. Inherited a forecast that went below the national
blend for low temps, and see no reason to stray significantly.
Lows ranging from mid to upper teens in the north to upper 20s
near Lake Michigan.

Sunday...Shortwave energy will be digging into the region.
Moisture through the column continues to look limited and
disjointed. But deep enough saturation looks to occur by midday
over central to north-central WI for a chance of light rain and
snow. The chance of light rain and snow will then spread northeast
over the course of the afternoon, and remain mainly north and
west of the Fox Valley. Perhaps a couple tenths of snow
accumulations are possible over the northwoods, but no travel
impacts are expected. High temps will range from the mid 30s north
to the low 40s over the southern Fox Valley.

.LONG TERM...Sunday Night Through Saturday
Issued at 225 PM CST Sat Nov 21 2020

Precipitation from Sunday will probably linger into Sunday night.
Mid-level moisture may get stripped out sufficiently to result in
some FZDZ. NW flow across Lake Superior may also keep some light
precipitation going in north-central into far northeast Wisconsin
for much of the night.

The main precipitation event during the period will occur Tuesday
into Tuesday night. A fairly substantial full-latitude trough will
initially head east from the West Coast, but undergo some
splitting as it progresses across the country. That will add an
additional layer of uncertainty to the forecast and make pinning
down details difficult. Will hold off on getting too specific with
the precipitation forecast and handle primarily with a mention of
the possibility of hazardous travel condition in the HWO for now.
At this point, central into north-central Wisconsin seem most at
risk of receiving at least a few inches of snow. Precipitation
could linger into Wednesday in eastern Wisconsin, though it may be
just warm enough for that precipitation to fall as mainly rain.

Quiet weather should return for the rest of the forecast period,
including Thanksgiving Day. A significant system may affect the
area just beyond the end of the period, but its track and
intensity will depend on if/when/how much phasing of the streams
occurs and so the models will probably have some difficulty honing
in on the evolution of that system until we get much closer to
the event.
&&

.AVIATION...for 00Z TAF Issuance
Issued at 506 PM CST Sat Nov 21 2020

VFR conditions and winds under 10 kts remain expected through
Sunday morning. Clouds will increase and lower late tonight
through Sunday as a weak trough tracks through the western Great
Lakes region. The trough will likely cause CIGS to lower to MVFR
across central and north-central Wisconsin Sunday afternoon, with
a chance for precipitation. Precipitation chances look to be too
low across central Wisconsin during that period, however will add
a PROB30 group for RHI given the better chance for -RASN to hit
the ground.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS.......Skowronski
SHORT TERM.....MPC
LONG TERM......Skowronski
AVIATION.......Kurimski



Area Forecast Discussion

National Weather Service Lincoln IL

 847 PM CST Sat Nov 21 2020

.SYNOPSIS...
Issued at 847 PM CST Sat Nov 21 2020

A cool and rainy night is in store across central and southeast
Illinois with low temperatures dropping into the upper 30s and
lower 40s. The rain will taper off and come to an end from west to
east Sunday morning, followed by mostly cloudy but dry conditions
during the afternoon.

&&

.UPDATE...
Issued at 847 PM CST Sat Nov 21 2020

02z/8pm surface analysis shows a 1020mb low over southwest
Missouri...with a large area of overrunning rain stretching from
the Ozarks northeastward into central Illinois. Local radar
indicates the heaviest/steadiest rain currently along/just north
of the I-70 corridor, although another rain band has formed
further north along a Rushville to Bloomington line. All models
suggest the rain will become widespread across all of central and
southeast Illinois from late evening through the overnight hours
before coming to an end from west to east by midday Sunday. Made
some minor adjustments to hourly PoPs, but the overall forecast is
right on track. Am expecting a rainy/cool night with lows ranging
from the middle 30s far north around Galesburg and Lacon to the
middle 40s south of I-70.

&&

.SHORT TERM...(This evening through Sunday)
ISSUED AT 357 PM CST Sat Nov 21 2020

The return of rainfall has begun across the region. Seeing almost
two bands of precipitation, one across the I-70 corridor, and the
other north of the I-72 region. The northern band has not reported
much reaching the ground, while the southern band is slightly
stronger reflectivity, with reports of rainfall in the bottom 6
CWA counties. This stream will continue to flow through the area
depicted, creating the potential for heavy rainfall across the
southern CWA. The associated frontal boundary remains just south
of the Ohio River, and is expected to lift slightly north
overnight as the Low pressure core moves into the mid-Mississippi
River Valley. The track of the core is forecast to remain south
of the CWA, through the Ohio River Valley overnight. This will
hold the heaviest rainfall across southern Illinois, with the
chance of up to 1.50 inches possible south of the I-70 corridor.

As this system exits the region Sunday, expect lingering shower
activity through the morning...with ending times through the early
afternoon across central and eastern Illinois. Temperatures will
remain seasonal through Sunday, with highs forecast in the mid to
upper 40s, while tonights lows only dip into the mid 30s far
north, while in the mid 40s across far south.

.LONG TERM...(Sunday night through Saturday)
ISSUED AT 357 PM CST Sat Nov 21 2020

Dry weather is expected to develop across the Midwest Sunday
night through most of Monday, as High pressure quickly builds
across the Midwest. This will be short lived, as another advancing
system tracks into the Midwest again Monday night into Tuesday.
This will push the High off to the east, bringing the return of
WAA to the region. There is signals of WAA rainfall arriving
overnight Monday into Tuesday, with a lull in activity anticipated
Tuesday afternoon. Like this system coming through tonight, the
main bands of precipitation and heaviest rainfall is likely to
occur Tuesday night into early Wednesday morning. The main
difference in forecast models, is that the track of the Low core
with this system will be through northern Illinois, possibly
clipping the IL River Valley. This will mean the heaviest rainfall
from this system will track through our coverage area. Models
indicate 1-2 inches of total precip from this event, however these
numbers typically decrease closer to the arrival of the system.

High pressure is then forecast to return across the region mid-
week, lingering through the end of the week. A few models hint at
another system approaching the region from the south towards the
end of the forecast period, however this will be left out of
discussion currently as models do not have great collaboration.

Temperatures through the upcoming week remain seasonal, with highs
through the week in the 50s, and lows dropping to the 30s and 40s.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 550 PM CST Sat Nov 21 2020

A wave of low pressure will spread low clouds/precip across
central Illinois this evening. 2330/530pm radar mosaic shows light
showers developing along/south of a KBMI to KUIN line. With an
initially dry boundary layer, it will take awhile before the
atmosphere moistens sufficiently to support precip reaching the
ground and even longer for ceilings to lower substantially. Based
on NAM forecast soundings and HRRR forecasts, it appears ceilings
will lower to MVFR at all sites except KPIA between 04z and
06z...then further northwest to KPIA by around 08z. As light rain
continues, IFR ceilings will develop everywhere except KPIA late
tonight into Sunday morning. Once the rain departs, a low overcast
will persist...until ceilings rise back to VFR west of the I-55
corridor after 20-22z Sun. Winds will initially be NE at 5-10kt,
then will switch to N/NW after FROPA Sunday afternoon.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Barnes
SYNOPSIS...Barnes
SHORT TERM...Baker
LONG TERM...Baker
AVIATION...Barnes



Area Forecast Discussion

National Weather Service Pueblo CO

 312 PM MST Sat Nov 21 2020

.SHORT TERM...(This evening through Sunday)
Issued at 312 PM MST Sat Nov 21 2020

This afternoon there are still a few low clouds near the eastern
border, while a few instability showers/clouds can be seen over the
mtns and high valleys.  The HRRR has be persistent in showing a
batch of showers moving off the southern Sangre de Cristo mtns this
evening, and then eastward across Huerfano and Las Animas Counties
and into Baca County through the evening.  The GFS also shows this
area of showers, so will go with some scattered showers in these
areas this evening. Low clouds are expected to back into the
southeast plains tonight but at this time are not expected to move
into the KCOS or KPUB areas.  By 12Z the forecast models show the
potential for low clouds shifting southward and being mainly over
Las Animas, Baca and Huerfano Counties. Otherwise dry weather is
expected tonight as an upper ridge starts building toward the area
from the west.

Sun the upper ridge will move over CO but will be quickly followed
by the next disturbance.  Most of the day Sun will be dry, but then
ahead of the the disturbance moisture will increase in the afternoon
and by late afternoon it looks like there will be some showers along
the Continental Divide, mainly over the eastern San Juan mtns. Temps
on Sun looks a little cooler, with highs in the 40s to lower 50s
over the plains, and mostly in the 40s in the high valleys, with
upper 30s to mid 40s in Teller County.

.LONG TERM...(Sunday night through Saturday)
Issued at 312 PM MST Sat Nov 21 2020

Sunday night through Tuesday...The first upper low pressure
system to affect the region will initially approach as an open
longwave trough, with a nearly constant southwest feed of moisture
across the Four Corners Sunday night through Monday morning. This
will bring snow to the higher terrain along the Continental
Divide as well as the Sangres, while the rest of the forecast area
will likely just experience increased cloudiness. Monday evening
the system begins to strengthen as it crosses into the Great Basin
and Rockies, with an associated cold front pushing south into CO
Monday night. The system will then continue crossing CO through
Tuesday, exiting to the east into Kansas that night. At this time,
total forecast snow amounts over the southwest mts range from a
foot to a foot and a half of new snow, while the peaks of the
central mts and the Sangres could see 6 to 12 inches of new snow.
Minimal amounts are expected over the Wets, Rampart Range and
Monument Hill, but this will need to be monitored for any possible
movement changes as snowfall in these areas would be tied to the
associated cold front late Mon night. Somewhat pleasant temps are
anticipated across much of the region on Monday, but with the
frontal passage, highs on Tuesday will be 10 degrees cooler across
the high valleys, and 20 degrees cooler across the plains.

Wednesday...Colorado will be between systems on Wed, with dry and
mild conditions forecast across the region. Maximum temps are
expected to be in the 40s and 50s for most areas.

Thursday through Saturday...Long range models are showing some
variance with the timing of the next system to affect the forecast
area. GFS is indicating an upper trough crossing the region Thu
and Fri, while the EC paints a slightly slower, and stronger,
solution with a closed low crossing AZ and NM Fri and Sat.
Obviously, confidence on timing is low though the one common
denominator is a system affecting Colorado on Fri, and the
extended procedure indicates the highest pcpn chances on Fri with
highs in the 30s and 40s. Stay tuned as the models start to fine
tune the system over the Thanksgiving holiday. Moore

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 312 PM MST Sat Nov 21 2020

VFR conditions and dry weather are expected at KPUB the next 24 hrs,
and winds will generally be 10 kts or less.  KCOS could see some
showers in the vicinity very early this evening, otherwise dry
weather is expected with winds mostly under 10 kts, however south
winds Sun afternoon should be 10-15 kts.  KALS could see a few
showers in the vicinity very early this evening, otherwise dry
weather and light winds are forecast, although southerly winds Sun
afternoon could increase to 10-15 kts.

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...28
LONG TERM...MOORE
AVIATION...28