Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/22/20
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
917 PM CDT Sat Mar 21 2020
.UPDATE...
Issued at 916 PM CDT Sat Mar 21 2020
Current forecast is on track, therefore no changes made at this
time.
UPDATE Issued at 623 PM CDT Sat Mar 21 2020
See updated aviation discussion below.
&&
.SHORT TERM...(This Evening through Sunday Night)
Issued at 333 PM CDT Sat Mar 21 2020
A shortwave, currently over eastern North Dakota, and surface low
pressure system over western South Dakota will push east across the
region tonight. With a fairly dry atmosphere, these systems should
pass through most of the CWA dry. There may be enough moisture and
lift in the eastward CWA for scattered flurries. The past couple
of runs of the HRRR does support the potential of light snow
tonight into the early morning hours on Sunday.
Another weak upper level trough and surface low pressure system will
track across the region Sunday afternoon through Monday night. This
system could bring light rain during the afternoon hours in the
Pierre area. As the system pushes east, the rain may transition over
to all snow over eastern South Dakota and western Minnesota. No
significant snow accumulations are expected.
.LONG TERM...(Monday through Saturday)
Issued at 333 PM CDT Sat Mar 21 2020
The extended period starts with westerly quasi-zonal flow aloft and
a surge of warm air. High temperatures for Monday and Tuesday range
from the upper 40s into the low 60s for some areas. Models do hint
at a minor shortwave passing through late monday night into Tuesday
that could bring some light precipitation in our eastern forecast
region. Given the warmer temperatures at the start of the work week,
only rain is expected during this time frame. Wednesday will see a
better chance at widespread precipitation as a long wave trough digs
into the rockies and a stronger shortwave is ejected out of the
southwest CONUS moving northeast into the northern and central
plains. A mixture of precipitation with light accumulating snow is
possible, however there are still model inconsistencies with timing
and track of this system.
With passage of this system, cold air advection moves over the
region again and temperatures drop for the latter half of the work
week with highs expected in the upper 30s to mid 40s through
Friday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
Issued at 623 PM CDT Sat Mar 21 2020
An area of MVFR cigs will linger over the far eastern part of the
CWA through the evening, including at KATY. Otherwise, VFR
conditions will prevail tonight and through the day Sunday.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...Parkin
SHORT TERM...SD
LONG TERM...Dye
AVIATION...Parkin
Area Forecast Discussion
National Weather Service La Crosse WI
946 PM CDT Sat Mar 21 2020
.SHORT TERM...(Tonight through Sunday)
Issued at 120 PM CDT Sat Mar 21 2020
Perky upper level shortwave trough currently dropping southeast into
ND, per latest watervapor satellite imagery, and progged to drop
across central MN and across northern WI overnight through Sun
morning. Good QG convergence accompanies the shortwave, stronger in
the 700:300 mb layer and between 00-12z. Some weak north-south
running frontogenetic lift indicated along with isentropic upglide
on the 280:290 K sfcs (mostly from 06-15z). 300 mb jet streak could
enhance the available lift overnight.
All in all, the shortwave has enough going for it to spark an area
of pcpn - main question is will it have enough saturation? Dry
easterly push across WI has dewpoints in the single digits to low
teens currently, and will continue that trend tonight. Mid/upper
level saturation will accompany the shortwave while a mid deck of
clouds ahead of the trough works in from the west. As for low
saturation, all the models suggest it will be on the increase this
evening (bufkit soundings, RH fields, time/height x-sections),
increasing the likelihood for pcpn and some minor accumulations.
Most models keep only light pcpn chances across northern parts of
mn/wi late tonight into Sun morning. However, meso models suggest
there could be some light pcpn this evening as the isentropic
upglide works on/increases the low saturation (drizzle look). The
RAP and HRRR then latch onto the better chances with the shortwave
for Sun morning, mostly north but perhaps a bit more south than the
NAM/GFS. Will increase chances for this evening (mainly southeast
MN) with concerns for light pcpn, then trend back to the north with
the high chances overnight.
On its heels, another shortwave trough will be lifting northeast
into the southern portions of the great lakes by Sun evening. Some
upper level qg convergence and low level thermodynamics found with
this feature along with west-east running frontogenetic support.
Latest track of this shortwave would bring pcpn chances to southern
portions of the forecast area for the afternoon-evening. Timing
favors rain as the main pcpn type. Meanwhile, some hints that a weak
ripple in the upper level flow could shift in from the west later
Sunday which could result in a smattering of pcpn.
.LONG TERM...(Monday through Saturday)
Issued at 120 PM CDT Sat Mar 21 2020
Models favoring a mostly zonal flow a loft for the new week with
temperatures moderating back to, or warming above, the late March
normals. The GFS and EC also favor sliding shortwave troughs across
and/or near the local forecast area, with resulting pcpn chances.
The first trough of note looks to move east/northeast out of desert
southwest, sliding across the mid mississippi river valley Tue.
Models in decent agreement with keeping the associated sfc low well
south, tracking across the oh river valley, but with enough lift
north of there that pcpn would reach across (at least) southern
portions of the forecast area. Temperatures/time of day favor mostly
rain, although could see a little snow mixed in at front
and back ends.
Another shortwave through is then progged to kick out of the
southern rockies, spinning across the upper mississippi river valley
wed/wed night. Current track would result in widespread pcpn, mostly
rain but with snow mixing in (or changing over to) overnight Wed as
the system departs.
Models have differing ideas how the rest of the week will shake out,
although both still suggest that other bits of upper level energy
could impact the region.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 945 PM CDT Sat Mar 21 2020
Light snow continues to spread across the area but is struggling
to reach the ground due to some lingering dryness in the low
levels. Most of this activity expected to clear out of RST by the
start of the TAF period with LSE seeing a small chance through
around daybreak. VFR conditions expected to persist until low
level moisture begins to increase Sunday afternoon. That will
likely lead to MVFR ceilings by late afternoon or early evening.
There are some hints of RST perhaps dropping to IFR by late in the
TAF period, but left this out for now due to lower confidence
that far out. Southeast winds the rest of tonight will increase a
bit towards daybreak with some gustiness likely during the day at
RST. Winds will become more southerly late in the day.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...Rieck
LONG TERM....Rieck
AVIATION...Kurz
Area Forecast Discussion
National Weather Service Green Bay WI
1044 PM CDT Sat Mar 21 2020
Updated aviation portion for 06Z TAF issuance
.SYNOPSIS...
Issued at 221 PM CDT Sat Mar 21 2020
Fairly quiet early spring weather is anticipated through at least
the first half of the upcoming work week. The potential for more
active weather will increase for the latter part of the work week
and into next weekend.
High upper heights will persist over the northeast Pacific
throughout the period. That will initially result in a
continuation of split flow downstream across North America.
However, as a trough settles into the Canadian Archipelago during
the latter part of the period, the trend will be for the
westerlies across the CONUS to become more consolidated, with mid-
continent troughing and ridging from the Gulf of Mexico to the
mid-Atlantic states.
A few scattered/light precipitation events are likely during the
first half of the forecast period, with the potential for more
significant precipitation increasing thereafter. The total
precipitation for the period will depend primarily on what falls
late in the period and thus is more uncertain than normal. The
best guess is for near normal amounts. Temperatures will begin the
period below normal, then warm and oscillate between near and
modestly above normal.
&&
.SHORT TERM...Tonight and Sunday
Issued at 221 PM CDT Sat Mar 21 2020
The latest RAP analysis and satellite/radar imagery show high
pressure centered over the northern Great Lakes early this
afternoon. East winds south of the high center is pushing a band
of clouds and snow showers/flurries off Lake Michigan and into
the northeast WI shoreline. Some of these flurries have reached as
far west as Marinette. Think these snow showers/flurries will
diminish as they move inland later this afternoon. Looking to the
west, a compact shortwave is diving southeast across North Dakota.
Clouds ahead of this system are already moving into far southwest
Wisconsin. As this shortwave moves across the region, light snow
chances are the main forecast concern in the short term.
Tonight...Skies will generally start out mostly clear at the start
of the evening. High pressure will be drifting off to the east,
but there may be enough time for temps to nose dive over far
northeast WI. As clouds increase from the west late in the evening
into overnight, temps should become relatively steady, and may
even rise a bit in the cold spots. Precip chances haven`t changed
much late tonight as moisture looks disjointed despite the compact
nature of the system. Lift from this shortwave will go a long way
towards saturating a very dry airmass left over from the
departing high. Forecast soundings suggest a brief period of light
snow or flurries remains likely over parts of central and north-
central WI late tonight. Perhaps a dusting will be possible. Lows
ranging from the low teens near the U.P. border to the middle 20s
over the southern Fox Valley.
Sunday...The shortwave will quickly move into eastern Upper
Michigan by midday Sunday. Lift and mid-level moisture will depart
with the shortwave, leaving behind broken cloud cover. Suppose its
possible that flurries could linger a little longer, but will have
light snow chances ending by midday Sunday. Maybe a tenth or two
of accumulations are possible early Sunday morning. Temps will be
warmer, and range from the middle 30s to lower 40s.
.LONG TERM...Sunday Night Through Saturday
Issued at 221 PM CDT Sat Mar 21 2020
The forecast area could get clipped by northern and southern
stream shortwaves crossing the region Sunday night. The best
forcing from each will pass north and south of the area, so went
with low-end PoPs. Precipitation type would most likely be snow,
though some rain is possible if precipitation begins before the
boundary layer cools off in the evening. Overall, the most likely
outcome is that most of the area will get just trace amounts or
stay dry. Edged temperatures up a little due to the expected
cloud cover.
Another low-end precipitation chance will occur Tuesday afternoon
and Tuesday night. There is still plenty of uncertainty in the
timing and track of systems during the latter part of the period,
but the large scale pattern will be much more supportive of
significant precipitation producing systems by that time.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1044 PM CDT Sat Mar 21 2020
Clouds will continue to thicken and lower overnight as an upper
level system approaches from the west. Moisture will be limited,
however upstream observations show the system is bringing some
light snow and some MVFR conditions as it passes through. Only
minor accumulations are expected, mainly over central and north-
central Wisconsin later tonight into Sunday morning. Conditions
should then return to VFR Sunday afternoon in the wake of this
system.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS.......Skowronski
SHORT TERM.....MPC
LONG TERM......Skowronski
AVIATION.......Kurimski
Area Forecast Discussion
National Weather Service Wichita KS
710 PM CDT Sat Mar 21 2020
.SHORT TERM...(This evening through Tuesday night)
Issued at 250 PM CDT Sat Mar 21 2020
Surface ridge continues to shift to the east into the Ozarks today,
with return flow and temperatures closer to normal today. Next
shortwave (currently over srn NM) will lift NE into the plains for
tonight, moving across KS by Sunday morning. Low level moisture
return ahead of this shortwave looks to increase during the evening
hours for most of the southern plains. Latest short range models
suggest this moisture will be delayed and previous shifts adjusted
the arrival of pops until after 03z. The combination of the lift
and the moisture transport ahead of it, suggests showers will
overspread the area tonight, and linger across most of the area
until Sun morning. Along with the moisture transport, also noticed
short range models are showing a little bit of elevated instability,
so added an isolated thunder mention for areas across south central
KS. Looking at the latest RAP model data, moisture transport doesn`t
look that impressive, as the shortwave moves across, which may limit
the amount QPF expected, even with the lift. So adjusted QPF amounts
down some, to mainly around quarter of inch for most locations, with
the highest amounts across the Flint Hills.
Warm advection associated with the moisture transport suggests that
this will be cold rain event with minimum temperatures in the upper
30s tonight. The slower moisture return also suggests that the light
rain may linger for most locations into the morning hours on Sun.
The morning rain and cloud cover will certainly limit max
temperatures on Sun with temperatures expected to only be in the
lower to middle 50s.
The next shortwave in the zonal flow will be quickly on the heels of
tonights shortwave, with this next shortwave moving across the
southern Rockies into the plains for Mon afternoon into Mon evening.
As the shortwave approaches for Mon afternoon, latest GFS and ECMWF
suggests that a low pressure area will develop across either the OK
Panhandle or SW KS with a dryline setting up across SW KS or wrn OK
for Mon afternoon. Will have to keep an eye on this setup, as bulk
shear and directional shear looks impressive. But there are still
differences, when it comes to timing and location of the low
pressure area and expected dryline for Mon afternoon/evening. Latest
GFS, looks to be the most ominous when it comes to a severe weather
chance for the forecast area, including supercells for portions of
southern KS, as the warm front pushes to along highway 50. Latest
ECMWF places the low further south, which would keep the higher
severe chances further to the south over northern OK. The NAM/WRF is
even slower, which may limit the severe weather risk for the
forecast area.
Limiting factor for widespread severe weather will be the marginal
instability (GFS MLCAPE values showing 500-750 J/kg). Still looks
like a good chance of showers and thunderstorms for most of the
forecast area by Mon evening, with strong to marginally severe
storms (even some supercell structures) given the impressive shear,
low instability setup. At this time dime to half dollar hail looks
like the main impact. But if the GFS verifies, a tornado cannot be
ruled out along the KS/OK border.
Ketcham
.LONG TERM...(Wednesday through Saturday)
Issued at 250 PM CDT Sat Mar 21 2020
Dry and mild conditions are expected for the middle of the week,
with max temperatures climbing back above normal. Medium range
models show a weak cold front will push across the area late Wed
night or early Thu. Consensus suggests a dry frontal passage as
moisture will be limited. Frontal boundary looks to slow or stall
across southern KS late Thu night. Overrunning moisture associated
with another weak shortwave in the zonal flow, may lead to a chance
of showers and embedded storms for late Thu across southern KS.
Ketcham
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 653 PM CDT Sat Mar 21 2020
*TSRA possible across southern Kansas tonight*
*Widespread MVFR/IFR conditions tonight through Sunday*
An upper level wave is moving out of the Four Corners region at
this time, and will move across the Central/Southern Plains
overnight. Current radar imagery shows minimal SHRA/TSRA activity
over Colorado and New Mexico. However, moisture is moving quickly
north into Kansas at this time and should lead to a fairly rapid
development of widespread SHRA and perhaps an isolated TSRA
between 03z/10pm and 06z/1am tonight. SHRA/isolated TSRA will then
continue into Sunday morning, before quickly ending from west to
east by the late-morning or early afternoon hours. For now,
thinking the best chance of TSRA impacts will be southern Kansas.
Given ongoing lightning along the Front Range of the Rockies, as
well as decent model agreement with instability, I felt confident
enough to add a TSRA mention at KICT. This may need to be added to
KHUT and KCNU with later updates if confidence increases there.
Martin
&&
.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT 40 56 39 62 / 100 40 10 20
Hutchinson 38 54 36 62 / 90 40 10 20
Newton 38 52 37 61 / 100 70 10 20
ElDorado 39 54 39 62 / 100 80 10 20
Winfield-KWLD 41 58 42 64 / 100 50 10 20
Russell 37 52 33 62 / 80 40 10 20
Great Bend 37 55 33 62 / 90 30 10 20
Salina 38 50 34 62 / 90 80 10 20
McPherson 37 52 34 60 / 90 60 10 20
Coffeyville 42 55 43 65 / 100 70 10 10
Chanute 40 52 41 62 / 100 90 20 20
Iola 39 52 40 62 / 100 90 20 20
Parsons-KPPF 41 54 43 64 / 100 80 10 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...Ketcham
LONG TERM...Ketcham
AVIATION...RM