Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/16/23
Area Forecast Discussion
National Weather Service La Crosse WI
553 PM CST Fri Dec 15 2023
.KEY MESSAGES...
- Light rain affects most locations over the next 24-30 hours.
Southeast MN into central WI has the highest potential for
precipitation through Sat morning, with a second round of rain
from northeast Iowa into southwest WI Saturday afternoon and
evening.
- Above normal warmth continues for the next week except for a
colder and brisk Monday. Wind chills Monday will be in the
single digits above zero.
&&
.DISCUSSION...
Issued at 211 PM CST Fri Dec 15 2023
Tonight into Saturday Evening: Periods of Light Rain
The overall forecast for the first half of the weekend remains on
track with the main concern revolving around the timing of rainfall.
An elongated shortwave axis now stretches from northern Oklahoma
into southern Saskatchewan early this afternoon, the result of two
distinct northern and southern stream vort lobes that are beginning
the merging process that takes place over the next 24 hours.
Broad kinematic support ahead of the northern stream wave,
coupled with ribbons of mid-level frontogenesis and moisture
profiles that are running near all time highs for this time of
year (+3-4 standard deviations), has fueled widespread rain over
central and northern Minnesota. Farther to the south, the
second low and its associated precipitation shield is meandering
northward through the eastern Kansas and on target to shift
into eastern Iowa by Saturday afternoon.
There is little zonal component to the 850-500-mb tropospheric flow
tonight into Saturday as the vort lobes merge, with dry E/SE near-
surface flow impinging on the eastern flank our initial
precipitation shield tonight into early Saturday morning. Short-
range guidance over the last 12-24 hours have trended slightly
westward with the QPF/PoP axis, increasing the possibility that
areas east of a Charles City, IA to Wisconsin Rapids, WI line may
stay dry through 12Z Sat. While one cannot completely rule out a
brief period of snow mixing in with rain across central Wisconsin
north of Highway 29 late tonight, trends have been for warmer
conditions with surface wet bulbs in the 34 degree range and a >0 C
warm layer of 1500-2500 ft thick. The direct NBM p-types are now at
100 percent rain for the entire forecast area tonight, and given
that wet bulbs this afternoon are already in the mid to upper 30s
with minimal changes expected in the near surface theta-e airmass,
have opted to follow the NBM trends and remove the mention of snow
from the forecast.
This elongated precip band decays late Saturday morning as the
southern stream wave becomes the dominant feature at play for the
afternoon and evening hours before departing. There remains decent
agreement in there being a stratiform precipitation shield lifting
north with this low over northeast Iowa into southern WI, but now
the 12Z run of the HRRR has started indicating some fragmentation to
this band. Bottom line, expect periods of light rain over the next
24-30 hours, but overall amounts and impacts look light.
Sunday Night and Monday: Remember What Normal In December Is?
A fast-moving northwesterly flow shortwave trough shifts through
late Sunday and Sunday night with a well agreed upon cool down in
temperatures and a brisk wind into Monday. Low-level temperatures
drop 10-15C Sunday night with the cold front and the well-mixed
boundary layer depth increases post frontally, accessing winds just
above 900mb. 15.00Z ECMWF EPS probabilities suggest a 40-50% chance
of exceeding 35 mph Monday morning west and south of La Crosse, with
widespread 90%+ chances of seeing 25mph+ gusts areawide. This
will bring wind chill values into the single digits for the bus
stop pickups Monday morning, only climbing about 5F during the
day. It is going to be a shocker to us after this above normal
1.5 months. Temperatures will struggle to climb in the face of
cold advection with highs in the 20s. At this time, forcing
looks pretty limited so it appears the lapse rates may just be
able to squeeze out some flurries.
Mild Conditions Quick Return For the Week
Warmer air quickly moves in Tuesday and remains through the week
under broad central U.S ridging with little weather impacts seen.
Above normal temperatures (~10F) are expected with highs in the 35-
45F range.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 546 PM CST Fri Dec 15 2023
VFR conditions fall to MVFR levels tonight due to rain and
lower ceilings along and northwest of an AUM to MDZ line. IFR
ceilings currently to the west of the region are expected to
spread east through the day Saturday, with a 20 to 40% chance of
IFR ceilings during the day Saturday. These chances increase to
60 to 80% by Saturday night into Sunday morning. Winds will
remain light through Saturday, before increasing from the NW on
Sunday. These NW winds will bring drier and cooler air and a
return to VFR.
&&
.CLIMATE...
Issued at 211 PM CST Fri Dec 15 2023
Running some statistics for La Crosse and Rochester, here is how
December temperatures are shaping up so far (thru Dec 14th):
La Crosse, WI (1872-2023)
Temperature Rank: 12th warmest
Mean Average Temperature: 34.2F
Rochester, MN (1886-2023)
Temperature Rank: 12th warmest
Mean Average Temperature: 30.0F
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...Baumgardt
AVIATION...JAW
CLIMATE...Baumgardt
Area Forecast Discussion
National Weather Service Columbia SC
908 PM EST Fri Dec 15 2023
.SYNOPSIS...
Moisture returns over the weekend as a potent storm system
emerges from the Gulf of Mexico. Rain and breezy conditions are
likely Saturday night through Sunday night. Expect drier and
colder weather Monday through mid to late next week.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
High pressure will slowly pull away toward the northeast overnight
as the systems over the Plains and the Gulf of Mexico continue to
advect in our direction. Mostly clear overnight, though the leading
edge of high clouds will begin to work their way into the region
from the south, with some mid-level clouds developing early Saturday
morning. Temperatures have fallen into the upper 30s and low 40s so
far, but may not drop too much further after the cirrus moves in.
Should be warmer than last night with lows in the low 30s north to
upper 30s south. Winds will begin to increase out of the northeast
around daybreak as well as the gradient begins to tighten ahead of
the weather system coming out of the Gulf.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
Surface low pressure in the Gulf of Mexico expected to strengthen as
an upper trough approaches. Increasing confidence in this trough
pushing this surface low through the Gulf of Mexico and towards
the northern Florida peninsula Saturday night. Increasing
onshore flow in the low levels and isentropic lift expected to
lead to increasing low clouds, especially in the CSRA, although
forecast soundings do indicate moisture remains relatively
shallow until late Saturday into Saturday night. As a result,
any rain during the day Saturday expected to remain relatively
light. As the upper trough approaches, strengthening SW flow
aloft should lead to deeper moisture over the forecast area.
Models have become much more consistent in favoring a track of
the surface low across north Florida and along the South
Carolina coast. This track remaining to the east of the area
significantly limits any severe threat as instability will be
limited. Impacts to our area will mainly include heavy rain,
especially Sunday morning where upper level divergence expected
to increase and low level moisture transport is likely
maximized. A fairly good spread remains in all the SREF members
for total QPF but in general, there is a cluster between around
2.5 to 3.5 inches of rainfall for Columbia, slightly higher to
the east and lower to the west. While much of the northeast
forecast area remains in a slight risk of excessive rainfall,
this will likely be more of a relatively long duration rainfall
event with the flooding threat mainly in poor drainage areas.
With fairly good agreement of this low pressure system being
anomalously strong, especially for December, winds expected to
increase out of the northeast ahead of the low, however, there
remains a question as to how much mixing occurs, with better
mixing likely behind the departing low. In general, GEFS and EC
means favor max wind gusts between 30 to 40 mph in the southeast
area and 20 to 30 mph in the northwest. With saturated soils
from the rainfall, it does remain possible that this causes
isolated tree damage. Low pressure should depart Sunday night
with rain beginning to taper off from southwest to northeast.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
Ensemble members are consistent in the low pressure system pushing
off to the northeast with GEFS and EC ens means dropping PWATs
rapidly Monday morning, below 0.7 inches and continuing to fall over
the course of the day. Wind gusts will likely remain breezy behind
the low with a lingering strong pressure gradient. Reinforcing upper
trough and surface cold front expected to move into the area early
next week. NAEFS mean indicates that the heights will be near the
tenth percentile. Anomalously strong high pressure likely behind the
front which will favor colder air settling over the area through mid-
week with blended guidance favoring temperatures well below
average.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
Relatively high confidence in VFR conditions through at least
18z Saturday. Ceilings lowering in the afternoon especially near
the AGS/DNL terminals.
Strong high pressure across the area early this evening with a
northeast low-level flow. Winds will be light through 06z then
expect northeast winds to increase toward Saturday morning as
low pressure develops in the Gulf of Mexico and pressure
gradient increases. Some higher clouds will move over the
region tonight. Strato-cumulus along the South Carolina coast
will advect inland after 06z and expect broken VFR ceilings by
12z. SREF/NBM and HRRR guidance suggesting MVFR ceilings
developing in the afternoon mainly at the AGS/DNL terminals, so
expect MVFR at those sites by 21z. Northeast winds near 10 knots
developing by 15z-18z.
EXTENDED AVIATION OUTLOOK...Moderate to high confidence in
restrictions and breezy conditions Saturday night through Sunday
night as a strong low pressure system moves from the central
Gulf of Mexico northward through the southeastern US. Breezy
conditions possible Monday.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
535 PM CST Fri Dec 15 2023
.Discussion...
Issued at 209 PM CST FRI DEC 15 2023
Key Messages...
- Light rain will continue to slowly move through the region
through tonight and Saturday. Definite (85 to 100%) chance that
everyone will see light rain at some point between now and
Saturday evening.
- Seasonable temperatures return this weekend, with dry
conditions persisting through at least mid-next week.
Detailed Discussion...
Through 1 PM, scattered light rain continues to slowly stream
northward across eastern Kansas and western Missouri. Looking
upstream across Oklahoma and Arkansas, it`s easy to infer the swath
of greatest isentropic ascent ahead of the mid-level low churning
east-northeast across south central Kansas, depicted on both
regional radar and WV imagery. We`ve picked up 0.02" here at the
home office, not surprising given the overall low rainfall rates
expected with this system. Surface dew points remain about 10 or so
degrees below the surface temps with RAP soundings confirming some
low level dry air to overcome. With southeasterly return flow this
afternoon, even with cloud cover, temperatures have reached the lower
to mid 50s F. To the east, across central Missouri, where more
breaks in cloud cover have existed, temperatures have pushed the
lower to mid 60s F, which are nearly 20 F degrees above normal for
the year. Generally, expect rain to continue to slowly build east
through the evening and overnight. The mid-level short wave trough
will continue to lift northeast, directly across the our region
through Saturday morning. Short range solutions haven`t wavered on
this solution. To the north, across the Canadian Rockies, another
H500 short wave trough continues to ride east, and remains on track
to slide southeast across the Dakotas and merge with our short wave
as it lifts into Iowa through midday Saturday. This feature should
help advance the east-northeast exit of precipitation through
Saturday afternoon. In the end, expect anywhere from a few
hundredths of an inch of rain to upwards of two to three tenths of
an inch, widespread across the region by the end of Saturday.
Into Sunday, the long wave trough will continue to move east, with
west winds developing at the surface and seasonable temperatures,
highs in the mid 40s to around 50 F. A second H500 short wave trough
will drop southward across the upper Midwest/western Great Lakes
overnight into Monday. This will result in northwest flow through
the column persisting, with chilly lows in the 20s Monday morning
and slightly breezy conditions before high pressure spreads in
through the day. Through mid-week, the long wave H500 ridge will
build along the Rockies through Tuesday, bringing a return to dry
and well above normal temperatures through mid-week.
Late week, Thursday into Friday, the long range solutions are a bit
divided, but overall, they develop another H500 short wave trough
lifting off the southern Plains through Thursday. In response,
precipitation chances (30 to 50%) for Thursday night into Friday.
Looking at temperatures, the region looks to remain well in the warm
sector, with boundary layer wet bulb temperatures hold in the upper
40s and 50s F.
Looking well ahead for the holiday weekend, it`s looking well above
normal with temperatures currently expected in the 50s and another
potential for rain on Christmas Eve and Christmas Day.
&&
.Aviation...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 534 PM CST FRI DEC 15 2023
IFR conditions will develop overnight and last until tomorrow
afternoon. IFR will improve to MVFR in the late morning Expect
light rain showers over the TAF location through midnight then
lower visibilities due to fog through mid afternoon tomorrow.
Brief gusty northwest winds are expected in the mid morning but
will diminish into the late evening tomorrow.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
Discussion...Kurtz
Aviation...MAK
Area Forecast Discussion
National Weather Service Hastings NE
533 PM CST Fri Dec 15 2023
.KEY MESSAGES...
- A steady band of light to moderate rain from around Osborne
and Smith Center Kansas up to Hastings, Geneva, and York,
Nebraska will continue throughout the evening gradually
shifting east late tonight.
- Afternoon/evening rainfall totals of 0.25 to 1 inch can be
expected within ongoing band of rainfall. A few snowflakes
could mix in after dark this evening, but snowfall
accumulation is not expected.
- Dry and warmer this weekend maxing our around 50 on Sunday.
Brief cool down Monday and then back into the 40s to around 50
through the end of the week. Slight chance for rain around
Thursday/Thursday night.
&&
.DISCUSSION...
Issued at 232 PM CST Fri Dec 15 2023
This afternoon/Evening (Precipitation)...
A very classic deformation band of precipitation has developed
across the southeastern half of our forecast area. The higher
resolution models are going to handle the precipitation amounts
better within this band and are indicating higher totals. The
18Z HRRR was giving us 0.75 to 1 inch rainfall totals within
the center of the deformation band in the Clay, Nuckolls,
Webster, Jewell County areas with lesser amounts towards the
edge of the band. The rainfall totals in the 12Z GFS and ECMWF
are too light. This band is peaking in both intensity and
coverage right now and will gradually begin to contract, weaken,
and slide a bit more to the east after 6 PM.
Possible Snow...
Forecast models continue to favor all rain or nearly all rain
with this event for most areas. The 20Z HRRR does indicate at
least some potential for a mixing with or change over to snow
for some areas in the heart of the band from around Smith Center
up to around Lawrence and Clay Center. The Smith Center
temperature at just after 3 PM was 35F. It will probably take a
surface temperature of around 34 to start seeing snow. It will
also take peak dynamic cooling on the backside of the upper low
within the heart of the precipitation band to get a little snow
out of this. Again most models are giving us just rain, but can
not rule out some snow mixing in or a period of change over to
snow in the center of this deformation band. Even if we do
change over to snow, it will be difficult to accumulate given
surface temperatures that will likely remain just above freezing
(33-34) while it`s snowing. Therefore, we are currently not
forecasting any accumulating snow, but again there is a small
chance (20%) that we might see some slushy snow accumulation (up
to 1 inch) mainly on grassy surfaces in the center of this
precipitation band generally in the Smith Center, to Lawrence,
to Clay Center area. If you live in this area, you will want to
keep an eye on precipitation type and a possible change over to
snow.
Saturday and Sunday...
This storm system will exit the area and we will dry out and
warm up. It will be rather breezy on both Saturday and Sunday
with a cool northwesterly wind behind the departing storm
system. However, Sunday will be a little warmer and with more
sunshine temperatures should be in the upper 40s to lower 50s by
Sunday afternoon.
Monday...
We get a backdoor cold front that cools us back down into the
30s northeast to 40s southwest.
Tuesday through Friday...
Dry and warmer again Tuesday and Wednesday with widespread upper
40s and lower 50s for highs beneath an upper level ridge.
The next weak shortwave will enter the area Thursday into
Thursday night bringing a slight chance (20%) for mainly rain.
It`s hit and miss in the models and ensemble members. The
temperatures are expected to remain warm through the end of the
week with mainly 50s for highs.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 528 PM CST Fri Dec 15 2023
Rain will continue for GRI into the early evening hours.
Ceilings will likely drop to MVFR around 05z or 06z and remain
until around 15z. Winds will mostly be out of the northwest.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
DISCUSSION...Wesely
AVIATION...Schuldt
Area Forecast Discussion
National Weather Service Midland/Odessa TX
541 PM CST Fri Dec 15 2023
...New AVIATION...
.SHORT TERM...
(This afternoon through Saturday night)
Issued at 203 PM CST Fri Dec 15 2023
Much of the area is seeing clear skies this afternoon and we will
continue to do so through at least Saturday evening. North to
northwest winds expected to stay put, continuing to filter in cool
air post cold front. Clear skies and light winds will also allow
temperatures to become cold tonight. Forecasted low temperatures
for much of the area will see overnight temperatures bottom out
around freezing with the exception of the Rio Grande Valley.
Fog may become an issue once again tomorrow morning as the HRRR
continues to pick up low clouds. The area that has the best chance
to see foggy conditions appears to be southeast NM along the Pecos
River. Calm winds and clear skies could allow for radiation fog in
this area.
&&
.LONG TERM...
(Sunday through Thursday)
Issued at 203 PM CST Fri Dec 15 2023
Northwest flow continues over the area through Sunday, but winds
at the surface will become westerly. Sunday`s high temperatures
will increase 3-7 degrees from Saturday as warmer and drier air
entrains in. Another cold front is expected to push in on Monday
morning, which drops temperatures 10-15 degrees. Clouds will
build into the area, moving southwest to northeast, early Monday
through the evening hours. If you`re not a fan of the cold,
thankfully a rebound is in store on Tuesday as upper-level ridging
builds over the area. Temperatures increase ~10 degrees on Tuesday
with plenty of cloudy skies and afternoon breezes. Breezy
afternoon conditions persist through the later half of the work
week. Long-range models hinting at a shortwave that quickly moves
north of the area, but Thursday morning appears to be the next
chance for rain for the area.
&&
.AVIATION...
(00Z TAFS)
Issued at 534 PM CST Fri Dec 15 2023
CAVU conditions will prevail across area terminals through sunrise
Saturday morning with light northwesterly winds forecast. Winds
will gradually shift around to a westerly/southwesterly direction
Saturday morning with a slight uptick in cirrus around FL300.
Overall, a great day for GA tomorrow!
&&
.FIRE WEATHER...
Issued at 203 PM CST Fri Dec 15 2023
Low fire weather concerns as minRH values generally stay 15-30%
over the weekend, but wind speeds will be light and westerly. Min
RH values increase over the work week with values of 30-50%. A
cold front will push in from the north early Monday morning
bringing a 10-15 difference of temperatures from Sunday.
Otherwise, calm and dry conditions can be expected until Thursday
where rain chances for the area increase.
&&
.PRELIMINARY POINT TEMPS/POPS...
Big Spring 33 60 33 65 / 0 0 0 0
Carlsbad 32 61 31 65 / 0 0 0 0
Dryden 40 64 38 71 / 0 0 0 0
Fort Stockton 35 63 39 70 / 0 0 0 0
Guadalupe Pass 36 56 37 61 / 0 0 0 0
Hobbs 30 59 33 66 / 0 0 0 0
Marfa 28 61 31 67 / 0 0 0 0
Midland Intl Airport 34 61 36 65 / 0 0 0 0
Odessa 35 61 37 66 / 0 0 0 0
Wink 33 62 33 68 / 0 0 0 0
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
TX...None.
NM...None.
&&
$$
SHORT TERM...70
LONG TERM....70
AVIATION...70