Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/21/20
Area Forecast Discussion
National Weather Service Dodge City KS
520 PM CST Fri Nov 20 2020
...Updated Aviation...
.SHORT TERM...(This evening through Saturday)
Issued at 1223 PM CST Fri Nov 20 2020
Morning water vapor satellite imagery and RAP analysis indicate a
mostly zonal polar jet is situated over the majority of the CONUS
with multiple embedded shortwave impulses. At the surface, high
pressure over the far northern plains and a weak low over north-
central OK has brought moderate north winds to southwest KS, and
these winds will weaken and turn northeasterly after sunset. These
winds combined with increasing cloud cover will hold afternoon
highs in the upper 50s to low 60s. One of the aforementioned upper
level shortwaves will eject from the central Rockies tonight into
tomorrow morning, overspreading an area of increasing moisture
and mid level frontogenesis over southwest KS to foster rain
development by tomorrow morning mainly for areas south of I-70.
Aided by the left exit region of an approaching 80-100 kt jet
streak, rain will likely be banded in nature, and this makes
predicting which locations will receive the most rainfall
difficult. Areas within any band(s) could see up to 0.25" of rain,
while areas outside will likely see less than 0.1". Given the
expected precipitation and overcast skies, afternoon highs on
Saturday are only expected to reach the mid to upper 40s.
.LONG TERM...(Saturday night through Friday)
Issued at 1223 PM CST Fri Nov 20 2020
Rain will likely be ongoing over portions of southwest KS at the
beginning of the long term period. Our southern zones will see a
period of moderate to heavy rainfall overnight Saturday into
Sunday morning as a potent shortwave impulse digs southeast from
southwestern Canada pushing the strongest zone of 700 mb
frontogenesis southward to near the KS/OK border. Sunday morning
lows will range from at or below freezing in our northwestern
zones to the upper 30s near Medicine Lodge as the zone of
strongest ascent and associated precipitation exits our area to
the southeast. QPF totals for the entire event Sunday afternoon
have trended drier and farther south, and now range from 0.1" just
south of I-70 to 0.3" near the KS/OK border. Locally higher
amounts are still possible owing to the likely banded nature of
the precipitation.
Once all the precipitation ends Sunday afternoon, the weather will
be cool but pleasant as surface high pressure builds into the
central plains, with highs in the upper 40s to low 50s expected.
Monday morning lows will likely drop below freezing for all areas
as light winds and clear skies optimize radiational cooling. South
winds will resume during the day Monday as another upper level
shortwave digs southeast out of the Pacific Northwest, and this
wave will bring another chance of rain for southwest KS Monday
night into Tuesday. This event currently does not seem like it
will be significant, as model solutions depict wave propagation
that is far too rapid for substantial moisture return. Therefore,
another quick hitting, light to moderate rain event that favors
the eastern zones appears the most probable at the moment. Beyond
Tuesday, predictability declines as medium range guidance differs
on the details of key synoptic features.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 517 PM CST Fri Nov 20 2020
Cloud ceilings will start to fall as low clouds building in later
this evening across southwest Kansas. Cloud ceilings should start
to fall to MVFR conditions between 06-12Z for DDC and LBL and
shortly after 12Z for GCK and HYS. Cloud ceilings could fall to
IFR conditions after 15Z as rain showers are forecast to start
developing around this time. Lowest cloud ceilings look to be
right around the 00Z time frame Saturday evening and after.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 36 43 35 51 / 10 70 50 0
GCK 34 44 32 49 / 10 60 40 0
EHA 38 49 35 49 / 10 50 60 10
LBL 36 49 34 51 / 10 60 60 0
HYS 40 47 32 51 / 10 50 30 0
P28 44 46 37 54 / 10 80 70 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Springer
LONG TERM...Springer
AVIATION...Tatro
Area Forecast Discussion
National Weather Service Green Bay WI
519 PM CST Fri Nov 20 2020
Updated aviation portion for 00Z TAF issuance
.SHORT TERM...Tonight and Saturday
Issued at 149 PM CST Fri Nov 20 2020
The latest RAP analysis and satellite/radar imagery show shortwave
energy moving east across the northern Great Lakes early this
afternoon. Cold advection is occurring across the region behind a
cold front that is moving into northern Illinois and southeast
Michigan. Within this colder low level airmass, cloud cover is
slowly spreading southeast as low level lapse rates steepen, but
clouds are having trouble overcoming the downsloping over
northeast Wisconsin. Some weak returns continue to show up over
northwest Wisconsin, and could see some flurries or other light
wintry precip move into Vilas county this afternoon as well.
Forecast concerns mainly revolve around cloud trends and temps
over the next 24 hours.
Tonight...Low level thermal troughing will remain present as
surface high pressure builds into the region from the west. Wind
trajectories veer to the northwest, which will likely keep clouds
present across the far northern Wisconsin through the night. But
low level dry air and downsloping should lead to clearing skies
over central WI to the Fox Valley. Winds will likely fall off late
and edged temps up a degree closer to the National Blend and
statistical guidance.
Saturday...High pressure will slide across the region, leading to
a quiet day. Any morning clouds lingering over far northern WI
should erode or exit early in the day. Otherwise, it should be a
mostly sunny and seasonable day with temps ranging from the low
30s to upper 30s.
.LONG TERM...Saturday Night Through Friday
Issued at 149 PM CST Fri Nov 20 2020
Fairly quiet weather is expected into early next week, with a
system bringing very light precipitation to northern WI Sunday
afternoon and evening. A stronger system will bring heavier
precip Tuesday and Tuesday night, with potential for a significant
snowfall over northern WI. Temperatures should remain within a
few degrees of normal.
Saturday night will be dry as surface high pressure lifts northeast
of the region. An upper level trough and associated cold front
will move through the region Sunday afternoon and evening, with
potential for a light wintry mix over north central WI Sunday
afternoon, and far northeast WI in the evening.
Weak surface high pressure and ridging aloft builds into the
western Great Lakes on Monday and Monday evening, bringing dry
weather. As the high slides east of the region, WAA will increase
on the nose of a 40-50 knot low-level jet late Monday night into
Tuesday. This will bring a swath of precipitation to the area.
Thermal profiles show snow at the onset with a mix or changeover
to rain as warmer air arrives ahead of the system. The GFS is more
aggressive driving the warm air north on Tuesday, while the ECMWF
suggests a better chance of snow lingering over northern WI. The
cold front and associated upper trough will move through Tuesday
night, followed by a decreasing trend in the precipitation
overnight. Will continue a mention of possible snow accumulations
over northern WI in the Hazardous Weather Outlook, as this could
impact early travel for Thanksgiving.
Mainly dry conditions are expected midweek, with high pressure
over the region Wednesday into Wednesday night, and a weakening
(and likely dry) cold front approaching the region on
Thanksgiving Day.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 519 PM CST Fri Nov 20 2020
A deck of MVFR clouds remains across the region with continued
cold air advection. There are signs of drier air making its way in
from the west on IR satellite imagery. Expect clouds to dissipate
during the overnight hours as this drier air works its way in from
the west. Once clouds clear out, they should remain clear with VFR
conditions for the rest of the TAF period.
Gusty northwest winds to 20 kts will continue into early this
evening, before subsiding as high pressure moves into the region.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......Kieckbusch
AVIATION.......Kurimski
Area Forecast Discussion
National Weather Service Lincoln IL
721 PM CST Fri Nov 20 2020
.SYNOPSIS...
Issued at 300 PM CST Fri Nov 20 2020
Clouds have built back across the region, and will linger
throughout much of the upcoming weekend, as Low pressure and
a frontal boundary impact the Midwest. As the frontal boundary
stalls near the Ohio River Valley, this will bring a widespread
opportunity for rainfall to southern Illinois, as well as some
locations in central Illinois. The Low pressure core will slowly
track into the region during the second half of the weekend,
finally moving out late Sunday. Dry weather returns briefly on
Monday, but additional precipitation returns Tuesday. Temperatures
were back above normal today in many locations, however with the
frontal boundary south of the area for much of the weekend, temps
will be on the cooler side.
&&
.UPDATE...
Issued at 721 PM CST Fri Nov 20 2020
01z/7pm surface analysis shows a cold front along the I-70
corridor. A band of light rain/sprinkles has developed immediately
to the north of the boundary...generally along a Danville...to
Decatur...to Jacksonville line. This area of rain is progged to
sink slowly southward and increase in areal coverage as the night
progresses. Based on latest radar trends and HRRR forecasts, it
appears locations south of a Paris to Taylorville line will see
the steadiest/most consistent light rain overnight. Further north,
cool and dry conditions are anticipated along/north of a
Rushville to Bloomington line. Low temperatures will range from
the middle 30s far north around Galesburg and Lacon...to the upper
40s far southeast at Lawrenceville.
&&
.SHORT TERM...(This evening through Saturday)
ISSUED AT 300 PM CST Fri Nov 20 2020
A very south moving frontal boundary is pushing through the region
currently. This will continue a slow progression southward through
the evening and into the overnight. Currently seeing returns on
radar, however most of this remains elevated due to the 15-20
degree spread in T/Td. Cannot rule out some sprinkles or very
light shower activity this afternoon and evening, but the main
event will not start until the overnight. Most of this is expected
to flow near and along the frontal boundary, which is forecast to
linger across southern Illinois. Rain will overspread that region
tonight into the start of the weekend. Increased PoPs into the
weekend and through the weekend, as model depiction indicated an
increased chance for widespread rainfall in this area. As this
boundary lingers across southern Illinois, the Low core itself
will slowly move through the southern Plains Saturday. Locations
north of the I-72 corridor will remain mostly dry throughout the
short term period, however some light precip this afternoon and
evening could occur in isolated locations.
Temperatures will cool overnight, remaining cooler than the past
couple of days into the start of the weekend.
.LONG TERM...(Saturday night through Friday)
ISSUED AT 300 PM CST Fri Nov 20 2020
As the Low pressure core works towards the region, models have the
track through the Ohio River Valley region, which will hold
precipitation mainly across southern Illinois. With this path, the
heaviest rainfall will occur south of the I-70 corridor...tracking
through our far southern CWA and into Indiana. The heaviest of
rainfall is expected Saturday night into Sunday morning as the Low
tracks across the region. Totals for this event range from less
than 0.10 inch in GBG to 1.50 in LWV. The majority of rainfall
will likely occur south of the I-70 corridor, however the I-72
corridor is forecast to receive nearly 0.50 inches of
precipitation. Heading into the second half of the weekend, some
of the precip could change to a mix, due to cooler temperatures
beginning to filter into the region. This trend is noted nw of the
Illinois River Valley, but no accumulations are expected as ground
temps continue to remain above freezing at this time.
A brief break in precipitation arrives Monday, as High pressure
quickly slides through the area. Then another system looks to
knock on the door heading into Tuesday. This will bring another
chance of rain to the region, however temperatures to start
Tuesday could be cool enough to mix in some wintry precipitation.
Since this is still a handful of days out, exact p-type is unknown
at this time. This will depend on timing of the arrival of precip,
temperatures (aloft and sfc), as well as system track.
Another dry period then arrives mid-week, lingering through the
end of next work week. Temperatures will slightly warm back into
the 50s mid-week, but the above seasonal temps are back out of the
picture through the forecast period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 542 PM CST Fri Nov 20 2020
VFR conditions will prevail through the entire 00z TAF period.
Latest regional radar mosaic shows scattered sprinkles developing
behind a cold front sinking southward toward the I-70 corridor.
Most CAMs indicate the sprinkles will persist for the next couple
of hours...with more widespread shower activity developing
along/to the north of the boundary by mid to late evening. All
solutions keep the most significant rainfall south of the
terminals tonight, with the showers dropping even further south
toward the Ohio River by Saturday morning. It appears a wave of
low pressure will track along the front on Saturday, with rain
spreading across much of central Illinois after 00z Sun. Have
therefore only carried VCSH at the TAF sites this evening, with a
mid-level overcast persisting through the entire period. Winds
will be N/NW at less than 10kt this evening, then will back to
N/NE on Saturday.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Barnes
SYNOPSIS...Baker
SHORT TERM...Baker
LONG TERM...Baker
AVIATION...Barnes
Area Forecast Discussion
National Weather Service North Platte NE
557 PM CST Fri Nov 20 2020
.SHORT TERM...(This evening through Saturday night)
Issued at 236 PM CST Fri Nov 20 2020
The area`s next chance for precipitation begins early Saturday
morning, lasting through the evening. An upper level trough will
track east through Nebraska over the next couple of days, which
will provide some upper level forcing for cloud formation. Slight
probability of precipitation is forecasted, mostly for areas south
of Interstate 80 and east of Highway 83. Models are trending
towards the majority of precipitation impacting areas in Kansas
and eastern Nebraska rather than western and north central
Nebraska. The ECMWF and GFS indicate stronger frontogenesis to the
south and east, a good indicator of where better precipitation
will fall. Those areas also have a bit better lower level moisture
availability indicated by GOES satellite imagery. HRRR and NAM
forecast soundings hint at lowered cloud ceilings on Saturday
morning in western and north central Nebraska, but dry air up to
10,000 ft AGL, meaning that substantial precipitation will have
trouble reaching the surface despite upper level support.
Overnight precipitation is expected to be in the
form of snow, becoming rainfall on Saturday morning as temperatures
warm up past freezing. Rain showers should move east out of the area
before midnight on Saturday night. Any snowfall is not expected to
accumulate on the ground and overall precipitation totals will be
just a trace to a few hundreths of an inch for western and north
central Nebraska.
Temperatures tonight should be somewhat warmer due to cloud cover
over the area, with lows in the upper 20s to low 30s. This cloud
cover will also prevent much of a warm up on Saturday, with highs in
the mid to upper 40s.
.LONG TERM...(Sunday through Friday)
Issued at 236 PM CST Fri Nov 20 2020
The troughing pattern is replaced by an eastward moving ridge on
Sunday. Building high pressure means clear skies and high
temperatures in the 40s. An upper level trough will begin to move
east past the Rockies on Monday and become established over the
central Great Plains by Tuesday. A low pressure system develops at
the surface, which will be the focal point of precipitation. GFS
seems to be hinting at around 250 J/kg of MLCAPE on Monday evening
into Tuesday morning. Although no thunder is expected at this
time, will continue to monitor. High temperatures on Monday
afternoon will be in the 50s, meaning precipitation from this
system will begin as rain. As temperatures cool in the evening, it
will turn into a wintry mix and eventually snow, then back to
rain on Tuesday after temperatures warm with sunrise. As of now,
the majority of this precipitation will be in north central and
southwest Nebraska and snow amounts looks light. Will continue to
monitor for QPF totals.
Upper level ridging should keep conditions dry for the rest of the
week. Temperatures on Tuesday will be in the 40s and 50s, then
increase into the upper 50s on Wednesday with the passage of a warm
front. By Thanksgiving highs will be back into the 40s thanks to
another cool front.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 554 PM CST Fri Nov 20 2020
VFR conditions are expected with high level clouds to persist
through the forecast period. Winds will remain light through the
overnight with a few gusts approaching 20 knots possible Saturday
afternoon.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...Meltzer
LONG TERM...Meltzer
AVIATION...NMJ
Area Forecast Discussion
National Weather Service Topeka KS
504 PM CST Fri Nov 20 2020
...AVIATION UPDATE...
.DISCUSSION...
Issued at 351 PM CST Fri Nov 20 2020
21Z water vapor imagery shows mainly zonal flow across the area this
afternoon with a shortwave moving onto the west coast of British
Columbia. The surface cold front has lingered in southeast KS as a
stationary front through the day; meanwhile, frontogenesis at 700mb
has kept mid-level cloud cover over east central KS since this
morning. Its northern extent hasn`t been handled well by the models,
although the northern edge has shown signs of scattering in the last
couple of hours. Given the frontal boundary`s location, far east
central KS should remain under cloud cover through the rest of today
into tomorrow. CAM guidance has been showing light reflectivity over
this area, mainly encompassing Coffey and Anderson counties this
evening and overnight. However, forecast soundings show an abundance
of dry air and subsidence below 850mb, with profiles becoming
increasingly dry through the overnight hours. Have opted to keep the
forecast dry for this reason until Saturday morning, with overnight
lows in the upper 30s to mid 40s - warmest in far east central KS
where more clouds linger.
After 12Z Saturday morning, isentropic lift increases at the 300-
305K layers, so rain chances increase from south to north through
the morning and especially afternoon when we have the highest PoPs.
Have generally slowed the trend of moving PoPs north, although this
could still slow down further pending the amount of dry air at the
surface. Both GFS and NAM forecast soundings at KEMP and KUKL keep
dry air below 800-850mb before fully saturating the column around 20-
21Z. This trend is similar further north at KTOP, though delayed by
an hour or two. Temperatures look to reach the upper 40s to near 50
for highs with cloudy skies all day. Heading into the evening and
overnight, we see a decrease in isentropic lift with drying in the
mid to upper levels as the aforementioned shortwave moves across the
Northern Plains. While there may be some lift associated with the
trough to keep light rain possible through the overnight, the better
forcing appears to be further north, so only have slight chance or
chance PoPs before drying out by sunrise Sunday morning.
Weak shortwave ridging passes over the area Sunday before the next
system approaches. A deeper trough digs into CA and NV with a subtle
shortwave ahead of it in our area by Monday morning, and there is
some variability among models on how much moisture comes with this
lead shortwave. If we get enough moisture for precip to develop,
morning temperatures in the 20s would support potential for snow
mixing with rain early before turning to rain in the afternoon with
temps in the 40s, but these PoPs are small until late Monday night
and especially Tuesday when the best lift and moisture arrives. It
should be noted that timing differences also remain with the passage
of the cold front ahead of the main trough, although at this time
the best rain chances look to be during the day on Tuesday. If
precip lingers later, some snow could mix in as temps fall to near
freezing by Wednesday morning. Dry weather should prevail in the
latter half of the next work week with ridging returning behind the
Tuesday system with no other notable sources of lift through Friday.
Temperatures look seasonal with 50s for highs and 30s for lows.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday)
Issued at 504 PM CST Fri Nov 20 2020
Dry low level air from surface ridging centered over the mid MO
river valley is expected to keep VFR conditions at the terminals.
Main question is how quick will low level moisture advect north.
Most guidance is showing lower CIGS by the last 3 or 4 hours of
the forecast period. However the 21Z RAP is significantly slower
with the moisture return potentially delaying any MVFR CIGS until
the overnight periods. Will follow the consensus for now, but
given trends over the last couple days, the -RA and CIGS could
still be delayed.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...Picha
AVIATION...Wolters