Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/03/20
Area Forecast Discussion
National Weather Service Dodge City KS
507 PM CST Wed Dec 2 2020
...updated aviation...
.SHORT TERM...(This afternoon through Thursday)
Issued at 1046 AM CST Wed Dec 2 2020
Snow has pushed out of northwest Oklahoma into southern counties
along the border seeing some decent amounts already for Comanche
to Meade County that was added to the warning to account for the
2-3 inches already fallen in those locations. More banding has
pushed through Barber to Kiowa and Ford Counties seeing up to an
inch in those parts expecting more to come later this afternoon
and evening. The question and forecast challenge will be with the
heavier bands pushing westward as it pivots around the occlusion
if it makes it to Seward County that is only in an advisory at
this time. HRRR models suggest that it should stay in Meade County
but will keep an eye on it as time moves forward. In the
meantime, expect 4-8 inches in the warning zone for these southern
counties with 2-4 inches for points west and northward in the
advisory. Coupled with the strong north winds gusting up to 35-45
mph, travel impacts will be significant in these areas as time
progresses this afternoon and evening for any after work commutes.
Otherwise, expect a continued cold and windy afternoon and evening
as temperatures will remain around where they are now in the low
to mid 30s under the cloudy skies that will persist into the
overnight hours. With this, expect overnight lows to drop only
into the 20s as radiational cooling will be pretty negligible
under these conditions. North winds will start to diminish by
early Thursday morning as snow tapers off and moves southeastward
out of the CWA through daybreak. Skies will improve west to east
through the morning hours of Thursday as high pressure builds in
across the high plains and upper level ridging extends off the
Rockies kicking the aforementioned upper level low to the east and
northeast into the Missouri River Basin. Temperatures Thursday
afternoon will only with the 30s in the snowpacked areas for the
southern counties with upper 30s to low 40s further north to the
I70 corridor where less snow if any at all will fall over the
course of Wednesday afternoon and evening. Another cold night for
Thursday into the upper teens to low 20s under clear skies and
much diminished winds pushing towards a dry and warm trend through
the weekend and the long term forecast.
.LONG TERM...(Thursday night through Wednesday)
Issued at 1200 PM CST Wed Dec 2 2020
Benign weather pattern is in store for the long term forecast as
upper level ridging will be set in place across the Rockies and
high plains giving way to the more generally dry northwest flow.
Expect a warmup after a cold start to end the work week on Friday
with upper 40s in the snowpacked areas of southern counties and
into the low to mid 50s further north that will not get the snow
near as much if any at all. Upper 40s to mid 50s will continue
over the weekend in the same areas and through early next week on
Monday before a southerly surge of warmer air pushes in on Tuesday
and Wednesday with strong downsloping due to leeside troughing
over eastern Colorado pushing afternoon highs into the upper 50s
and even low 60s for the entire CWA. Morning low temperatures
through the time frame with be in the 20s for the most part before
pushing into the 30s for early next week with the aforementioned
warmer air. Dry and warmer will be the story for the long term
after the active short term weather, with extended outlooks
looking more bleak in terms of being below average for
precipitation and above average for temperatures through the end
of the month.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 501 PM CST Wed Dec 2 2020
Poor flight conditions will continue this evening. A winter storm is
ongoing at the current time. Snow bands of light to occasionally moderate
snow with LIFR cigs and vis will prevail this evening. This is particularly
true for the KDDC and KLBL terminals. KHYS should remain north of the
main snow band throughout this event. Cigs and vis will slowly improve
towards mid to late morning as the weather system exits out of the
terminal aerodrome forecast space.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 23 37 22 51 / 90 10 0 0
GCK 21 39 20 53 / 90 10 0 0
EHA 20 39 22 53 / 80 10 0 0
LBL 20 37 19 49 / 90 10 0 0
HYS 24 41 23 54 / 20 10 0 0
P28 28 35 22 49 / 90 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until 6 AM CST Thursday for KSZ087>090.
Winter Weather Advisory until 6 AM CST /5 AM MST/ Thursday for
KSZ061>066-074>081-084>086.
&&
$$
SHORT TERM...Lowe
LONG TERM...Lowe
AVIATION...Sugden
Area Forecast Discussion
National Weather Service Des Moines IA
539 PM CST Wed Dec 2 2020
...Aviation Update...
.DISCUSSION.../Tonight through Wednesday/
Issued at 250 PM CST Wed Dec 2 2020
Synoptic Overview:
Highly amplified pattern remains in place for the CONUS. 300mb
analysis reveals a closed low circulation over the far northeast
CONUS this morning, with another closed low centered over the OK/TX
panhandles. There is then an amplified ridge along the western
CONUS. For this morning and afternoon, Iowa will remain in an area
of weak mid to upper-level flow. At the surface, there are not any
features of consequence. There is deepened surface cyclone in the
Ark-La-Tex region associated with the western closed low, and then
another one in eastern Canada with the northeastern H3 closed low.
Surface high pressure has been building in the Northern Rockies
downstream of the western CONUS ridge. The overall pattern will be
rather slow to change given that there is not much to kick these
systems away.
Today Through Saturday Afternoon:
A few high cirrus clouds may work their way across the sky this
afternoon ahead of the closed low entering the southern Plains but
will continue to see plenty of sunshine, as the upper-level flow
remains rather week. Expecting a moderate drop in temperatures this
evening given that winds will be weak with clear skies allowing
radiational cooling to be dominant. Have kept overnight low
temperatures below the 50th percentile. Tomorrow, the closed low
will continue to slowly propagate across the southern Plains, and
will try to edge northeastward but will still miss Iowa. Models are
indicating some weak isentropic ascent across the forecast area
early Thursday Morning that may result in stratiform cloud cover.
HRRR and a few other CAMs have been hinting at overcast skies from
about 7-13z in the morning. However, the forcing is not overly
strong, so there is some uncertainty with the extent of stratus
cover, as well as how long it may linger into the afternoon if it
does develop. That leads into the temperature forecast for Thursday
afternoon. Today`s (Wednesday`s) over performance of temperatures
decreased confidence in a large number of model solutions for
temperatures over the next few days. For Thursday afternoon, the
spread in solutions was not that much, which helps. Given the dry
conditions that have been ongoing, Thursday`s highs were set between
the 75th and 90th percentiles. This bumped temperatures up 2-3
degrees from starting NBM guidance. However, should the stratiform
cloud cover linger past 18z, this will inhibit insolation, and keep
temperatures much lower. As mentioned before, the sky cover forecast
does have a decent amount of uncertainty with it, thus so do
temperatures. This could also vary across the CWA. Some areas may
clear out in time to reach the 90th percentile temperatures, while
other areas do not and remain between the 50th and 75th. Satellite
trends will need to monitored closely overnight and Thursday
morning, with updates to temperatures made accordingly. For Friday,
center of the closed low moves across Missouri and into the middle
Mississippi River Valley. The axis of the ridge in the western CONUS
will slide east over the Rockies. This will put Iowa in NW mid to
upper-level flow Friday being east of the axis, and will setup an
AVA regime allowing for large scale subsidence that will clear skies
out. Even with northwesterly flow, temperature advection does not
appear to be overly strong, so with clear skies insolation should be
plentiful to provide another decent diurnal warmup Friday afternoon.
With no pending stratus, confidence in Friday afternoon high
temperatures is slightly higher. Even with the low pressure passing
to the south, and best convergence and moisture remains far removed
from the forecast area. Thus, no precipitation is forecast. This
same trend continues into Saturday, everything is too far south for
activity.
Sunday and Beyond:
Sunday, GFS and ECMWF drop another closed-low southward from Hudson
Bay into the upper Midwest. The 12z GFS takes the center closed low
further east almost directly over Lake Michigan, while the ECWMF
drops this southward following closer to the Mississippi River
Valley. Even with the ECMWF solution, the bulk of the forcing and
moisture remain east of the forecast area. The NAM does try to hint
at some saturation early Sunday. However, looking at the ensemble
suites, very few members have any appreciable QPF Sunday, thus will
maintain a dry a forecast for Sunday at this time. But, certainly
cannot completely rule out the possibility for a brief period of
drizzle or flurries as this features passes by. The setup though is
not favorable for any accumulation. Monday into Tuesday, weak
thermal ridge rides into Iowa behind the closed low system, which
will bump temperatures back up and keep conditions dry. Another
short-wave is forecast to drop through the upper Midwest late
Tuesday Night into Wednesday, although the GFS and ECMWF are not in
agreement on the location. Even with decent forcing with this
system, the lack of moisture supply will keep the forecast dry for
Tuesday into Wednesday, and this will be the case for the rest of
the official 7 day forecast. Currently, the next signal for
accumulating precipitation is not until next week on Friday.
&&
.AVIATION.../For the 00Z TAFS through 00Z Thursday evening/
Issued at 536 PM CST Wed Dec 2 2020
Incoming, relatively narrow, stratus deck form the NW may provide
a window of a few hours of MVFR ceilings overnight into tomorrow
morning. Have put MVFR mentions at all sites except KOTM for the
time being, and should have a better idea of the extent by the
06z issuance. Otherwise, VFR returns by late morning/early
afternoon Thursday.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...Krull
AVIATION...Curtis
Area Forecast Discussion
National Weather Service Goodland KS
546 PM MST Wed Dec 2 2020
.SHORT TERM...(This evening through Friday Night)
Issued at 1222 PM MST Wed Dec 2 2020
19Z Water Vapor Imagery and RAP analysis indicated large closed
low centered over the Texas panhandle, with two distinct PV
anomalies rotating around the low circulation, the northern most
anomaly likely aiding in area of precipitation across the area.
Main forecast concerns will center around timing out the end of
precipitation across the forecast area, followed by how cold
things get tonight. Otherwise weather will be quiet for the rest
of the period.
290K isentropic surface does not show a very optimal advection
pattern concerning precipitation continuing into the evening as
pressure advection rapidly weakens and drier air advects into the
area. Most of this afternoons precipitation has been aided by weak
sfc based instability which has allowed showers to persist. This
should diminish through the afternoon and evening as warm air
advection displaces colder air. One concern I have is that as this
unstable layer decreases, the potential for ice being in the
clouds decreases as well. While not likely, could see a 1 or 2
hour window with patchy freezing drizzle as things wind down.
Threat not high enough to warrant an advisory, but does bear
watching closely.
Otherwise ridge over the Rockies will build over the rest of the
period leading to warming temperatures and dry conditions. For
highs have kept things on the warm side of guidance per recent
biases. With light winds, some fresh snowcover and clearing skies
did push forecast towards coldest solutions tonight, with lows
falling into the lower teens in the west.
.LONG TERM...(Saturday through Wednesday)
Issued at 116 PM MST Wed Dec 2 2020
An exceptionally quiet long term period is on tap. High amplitude
ridge will be in place across the length of the High Plains on
Saturday, which gradually moves east and weakens by early next
week. Some model differences in the upper pattern begin to emerge
afterwards, with the ECMWF a tad stronger and further south with
the northwest flow, compared to the GFS which shows more of a
zonal flow. About the only impact noticeable would be slightly
warmer temperatures Monday through Wednesday in the ECMWF, aided
by a persistent downslope component in the surface winds. Message
for the long term period will be dry conditions and above normal
temperatures.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 539 PM MST Wed Dec 2 2020
MVFR ceilings will persist through most of the evening, lifting/
scattering to VFR after midnight. Mostly clear skies will prevail
on Thursday. Breezy north winds (15-20 knots gusting to ~25 knots)
will decrease to 10-15 knots late this evening -- backing to the
NW during the day on Thursday.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JRM/EH
LONG TERM...024
AVIATION...VINCENT
Area Forecast Discussion
National Weather Service Marquette MI
704 PM EST Wed Dec 2 2020
.SHORT TERM...(This evening through Thursday)
Issued at 359 PM EST WED DEC 2 2020
Water vapor imagery and RAP analysis show an amplified, split flow
pattern across N America this aftn. Ridging over the western U.S.
extends into sw Canada with another ridge over the N Atlantic.
Strong positive height anomalies at 500mb (around 370m over sw
Canada and around 400m centered just off the Newfoundland coast) are
only separated by weak troffing extending from the Canadian Arctic s
to Hudson Bay. To the s, a closed mid-level low is centered over the
TX panhandle with another over Quebec. Resultant flow across Upper
MI this aftn is from the nw. Within this flow, a shortwave is noted
across northern Ontario into northern MN. At the sfc, the associated
trof is moving out across western Lake Superior attm. Abundant low
cloudiness follows the trof. Obs within the cloud deck indicate some
spotty flurries, and a report of -fzdz was noted on an ob from CYXL
in northern Ontario. Closer to home, it`s been a mild day for early
Dec as temps have pushed into the upper 30s to mid 40s. With a
couple of exceptions, much of the area enjoyed abundant sunshine
today. Some lake stratocu has been noted across nw Upper MI, and
lake stratocu over the eastern fcst area has been shrinking in
coverage.
Approaching shortwave will swing across the area this evening, and
with the passage of the associated sfc trof, low clouds will
overspread the fcst area. Fcst soundings indicate temps at the base
of a low 3-5kft inversion will fall to -8 to -10C tonight, coldest
over the e. With lake sfc T running 4-6C, conditions will become
just cold enough for wnw flow lake effect pcpn, mainly off eastern
Lake Superior. Although upstream radars aren`t showing any returns,
there may be some spotty light pcpn (flurries/-fzdz), beginning a
few hrs after trof passage across the w where upsloping w to nw
winds add a boost to lift. Otherwise, as temps at inversion base
fall, some light lake effect pcpn should get underway, mainly
downwind of the e half of Lake Superior. Given temps in the moist
layer flirting with -10C for ice nucleation, pcpn type could be
liquid (-dz/-fzdz) and/or -shsn/flurries. Fcst will reflect this
mix. Pcpn will be light, but where temps slip blo freezing inland, a
very thin glaze of ice may form, especially on elevated surfaces.
Late tonight into Thu morning, mid-level moisture is fcst to arrive,
but it`s not certain that this mid-level moisture will link down to
the low-level moisture. So, will continue with the mix wording. If
the moisture does link, -shsn coverage will certainly increase for a
time into the eastern fcst area (the hourly RAP/HRRR runs are most
suggestive of this scenario).
Light pcpn over the e will diminish on Thu, and may end Thu aftn as
winds back ahead of a stronger shortwave approaching from the nnw.
Otherwise, abundant low cloudiness to start the day will gradually
clear out across the far w into the central as winds back during the
day. While cooler than today, it will be another mild day for early
Dec with highs in the mid to upper 30s.
.LONG TERM...(Thursday night through Wednesday)
Issued at 240 PM EST WED DEC 2 2020
As board troughing establishes itself following the breakdown of the
short term period`s omega-like mid-level pattern, the Upper Great
Lakes will be under persistent NW, N or NE flow through the extended
pattern. Given that this pattern positions the 300mb jet over the
region for much of the region, the road shortwaves will drive
southeast on will come through the Upper Great Lakes region.
Despite this though, minimal moisture will limit big precip
potential in this period.
Thursday night, multiple shortwaves will setup to the north and
begin their trip southeastward into the region. The first looks
to swing through by Friday morning, followed by 2 more by Friday
night. Each of these shortwaves look to present low end pop
chances for light snow/flurries/fz drizzle in the northwest to
north wind belts in the east given the dearth of mid-level
forcings and a healthy amount of dry air. Much of the guidance
looks to support light lake effect precip given the sub-5k feet
inversion and delta-Ts. Given inverted v soundings as well,
precip will likely have trouble overcoming the dry lower levels.
Overall accumulations Thursday into Friday night look to be on the
order of an inch or less, mainly in the east. Overnight lows look
to be in the 20s Thursday night. High pressure pushing into the
region from the west Friday night should help clear skies out
some, which would support lows sinking into the teens in the
interior west. During the day Friday, daytime highs should top out
in the 30s.
The high looks to dominate conditions on Saturday. On Sunday the
guidance is mixed and largely varies on the timing and position of a
nor`easter moving up the Atlantic Coast and how quickly the high
exits our region. If the high exits quickly, as supported by the
GFS, a weak shortwave could move southeast into the region on
Sunday. This looks to be an outlier at the moment, with the Canadian
and European solutions maintaining the high over the region,
reducing the intensity of this shortwave, or devolving it into a
snicket as it butts up against the ridge over the Lake.
Looking at next week, guidance continues to present a mixed bag of
solutions. Ensembles suggest positive height anomalies stretching
into the Upper Great Lakes, which would suggest continued above
normal temperatures and no big snow events.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 704 PM EST WED DEC 2 2020
This evening, a passing sfc trough and accompanying low-level
moisture will result in low MVFR cigs over the west spreading into
KSAW. Cigs may drop to IFR at KCMX but more likely at KIWD. Also,
there could be a few flurries. Backing winds Thursday morning will
result in low clouds clearing out at KIWD/KSAW. Meanwhile, KCMX is
expected to remain under low MVFR cigs through the morning. West
winds should gust to around 25kt through the forecast period at
KCMX.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 359 PM EST WED DEC 2 2020
With a sfc trof passage this evening, expect w to nw winds of 20-
30kt across Lake Superior thru tonight. A few gale force gusts will
be possible across the e half of the lake this evening. Winds will
remain mostly in the 20-30kt range across Lake Superior on Thu. A
cold front will then drop s across Lake Superior Thu night. Despite
its passage, a weaker pres gradient in its wake will result in winds
diminishing. Winds on Fri will be under 20kt, lightest across
western Lake Superior, closer to approaching sfc high pres. Sfc high
pres will then drift across the area Fri night/Sat, leading to a
period of light winds mostly under 15kt. A weak trof may pass late
Sat night/early Sun, but no significant increase in winds is
currently anticipated. Winds Sun/Mon should be mostly under 20kt.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...JP
AVIATION...JLB
MARINE...Rolfson
Area Forecast Discussion
National Weather Service Paducah KY
1000 PM CST Wed Dec 2 2020
.UPDATE...
Issued at 1000 PM CST Wed Dec 2 2020
Minor adjustments made to temperature and dewpoint trends
overnight and into Thursday. Similar adjustments were made to
increase thermal profile, CAPE, and precipitation type trends
closer the the RAP guidance.
The overall impact was to reduce the potential for effective
snowfall potential over the Ozark Foothills and parts of southwest
Illinois between 2 am and 8 am CST Thursday. Do not anticipate any
accumulating snow in these areas during that time period.
Reflected this change in the Hazardous Weather Outlook as well.
&&
.SHORT TERM...(Tonight through Thursday night)
Issued at 304 PM CST Wed Dec 2 2020
A surface low will drift along the Gulf Coast by early Thursday as
an upper level low moves toward the middle Mississippi. Models
indicate our region will be on the northern fringes of available
moisture as the surface system gradually weakens on its eastward
trek. Clouds will increase tonight, and models bring some
precipitation into our far western counties by late tonight. As
precipitation spreads east on Thursday, coverage will become more
hit-and-miss as the day progresses. Went with good chances for
our far west counties late tonight, with chances spreading east
but decreasing to slight by Thursday afternoon.
With overnight lows in the upper 20s to lower 30s, precipitation
will begin as light snow in much of southeast Missouri and
southwest Illinois, but any light snow will become mixed with then
change over to light rain by mid morning. Some accumulation may
briefly occur on grassy areas, but rain and warming temperatures
will wipe this out pretty quickly as readings climb through the
30s. Just slight chances of light rain are expected Thursday
afternoon with highs in the 40s.
By Thursday night, the upper low will be just west of the PAH
forecast area, and this will reinvigorate our precipitation
chances mainly across west Kentucky. Lows in areas with
precipitation should only fall into the middle to upper 30s, so
only rain is expected. The rest of our region will see lows in the
lower 30s.
.LONG TERM...(Friday through Wednesday)
Issued at 304 PM CST Wed Dec 2 2020
Friday morning an upper low is forecast to be across the area. Best
moisture will be across the TN Valley into east KY. Will hold on to
minimal rain chances across west KY Friday, then end precip chances
for Friday night through Saturday. The GFS, as an outlier, seems to
hold on to moisture and precip too long (into Saturday). The wave
should be "kicked" along by upstream energy and a general phasing
with the primary upper trof over east Canada. For next week, a
chaotic flow pattern will be mostly a NW flow regime for our area,
resulting in on and off clouds and near or slightly below normal
temperatures. The forecast is dry for now. We`ll monitor in case one
of these weather systems comes in with slightly more moisture than
advertised. Any precipitation would be of little consequence.
&&
.AVIATION...
Issued at 537 PM CST Wed Dec 2 2020
For the 00z Thursday WFO PAH TAF issuance, there will be a
gradual downward transition during the first 12 hours from broken
and overcast high level cirrus to mid-deck clouds. Around 12-13z
Thursday anticipate some light precipitation, most likely a mix
of rain and snow, changing to rain through noon, especially over
KCGI and KPAH. However probabilities for measurable accumulation
will be small, so left a vicinity mention of shower activity at
these airports.
VFR ceilings will dominate all of the TAF sites through the
forecast period. With a dry slot expected to move through most of
the TAF sites during Thursday afternoon, little additional
saturation of the low atmosphere is expected, reducing the
potential for a drop below visual flight category for the rest of
the forecast period.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
UPDATE...Smith
SHORT TERM...RST
LONG TERM...08
AVIATION...Smith