Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 11/25/22

Area Forecast Discussion

National Weather Service Lubbock TX

 545 PM CST Thu Nov 24 2022

...New AVIATION...

.SHORT TERM...
(This evening through Friday)
Issued at 213 PM CST Thu Nov 24 2022

18Z upper air analysis depicts a deepening closed cyclone over the
southern Rocky Mountain range with a 300 mb jet streak near 145 kt
digging south-southwestward along its western flank juxtaposed to
the 300 mb sub-tropical jet streak at around 120 kt over the State
of Texas. Further west, a highly amplified mid/upper-level ridge is
positioned across the western U.S., with its amplitude modulated by
the northern tranche of the 300 mb jet streak rotating atop the
ridge over Alberta and British Columbia. This has resulted in the
closed cyclone to deviate southwestward over the last 12 hours, with
the 500 mb core currently positioned over south-central New Mexico.
GOES-East water vapor imagery also detects the infant stages of a
secondary baroclinic leaf, upstream of the primary one over
northeastern Texas, developing over the Texas Panhandle due to the
sharp increase in high-level difluence as a series of smaller-scale
shortwave perturbations rotate about the base of the cyclone and
eject over the High Plains. At the surface, strong, northerly winds
persist across locations west of the edge of the Caprock Escarpment
with the polar front located south of the I-10 corridor as per
recent West Texas Mesonet and regional METAR data. A Wind Advisory
remains in effect for Bailey, Castro, and Parmer Counties until 6 PM
CST as those locations remain within the eastern periphery of the
corridor of strongest winds, and the West Texas Mesonet sites within
those counties have clocked gusts as high as 54 mph. Pressure
tendencies have started to stabilize, with pressure rises averaging
at around 1-2 mb/3 hr, though advisory level winds are expected to
persist through at least dusk. Sustained wind speeds diminish across
the eastern Rolling Plains as the attendant surface cyclone is
located in the Texas Big Country with blustery conditions elsewhere
across the CWA.

Meanwhile, a shield of low stratus continues to advect southward as
the columns saturate at the top of the frontal airmass as 700 mb
flow backs to the east. Recent WSR-88D imagery out of LBB and
neighboring sites have detected weak echoes, with light rain
expected to develop and move southward across the CWA this afternoon
and into the evening hours as moist, isentropic ascent maximizes
within the low-levels. The 700 mb upper air map at 12Z this morning
sampled temperatures at around 8 deg C across southeastern Texas,
and as the core of the closed cyclone continues to move southward
over northern Chihuahua, southerly flow will begin to back over the
CWA and result in the development of a bonafide TROWAL. The
resultant warm nose/cap and slight mid-level cooling may yield a few
hundred J/kg of MUCAPE, though the thinking is that with the columns
near complete saturation, the potential for updrafts of any kind to
produce lightning is low. Based off modifications to the upper air
observations, a slight chance of thunderstorms has been kept in the
official forecast, but confidence in this particular prognostication
is low. The initial wave of precipitation will start out as plain
rain area-wide late this afternoon and tonight, with a transition to
mixed-phased precipitation across the extreme southwestern TX PH.
Minimal accumulation of mixed-phased precipitation is expected
tonight across the northwestern zones as easterly 850-700 mb flow
backs to the northeast which should offset the magnitude of moist,
isentropic ascent within the low- and mid-level theta surfaces while
the TROWAL remains intact. A lull in precipitation is therefore
expected across the extreme southern TX PH tomorrow morning while
chances for plain rain and/or wintry mix increase heading into the
rest of the South and Rolling Plains, with any wintry mix confined
to the western South Plains tomorrow morning as surface wet-bulb
temperatures are forecast to be near or slightly below freezing.

The amplitude of the mid/upper-level ridge over the western U.S. is
forecast to attenuate as a positively-tilted shortwave trough pivots
over the Pacific Northwest tomorrow morning. This will result in a
corridor of strongly confluent flow developing over the central
Rocky Mountains, and in turn, steer the closed cyclone to the east
and east-northeast towards far southwestern Texas and the Big Bend
region. Precipitation chances will quickly increase area-wide late
tomorrow morning and into the afternoon hours, with the expectation
of moderate-to-heavy rain overspreading most of the CWA with heavy
snow mixing in across the western zones. By this time, the 700 mb
temperatures mentioned in the previous paragraph across southeastern
Texas are forecast to arrive, augmenting the depth and magnitude of
the TROWAL in an east-to-west manner. Cold rain is expected across
the Rolling Plains as the structure of the vertical thermodynamic
profile remains saturated near the 0 deg C isotherm aloft, which is
sub-saturated with respect to ice. Further west towards the TX/NM
state line, the columns are forecast to be saturated with respect to
water within the ice nucleation layer, and therefore, supersaturated
with respect to ice before encountering wet-bulb temperatures near
or above freezing in the low-levels. This will yield a potentially
heavy, wintry mix with snow-to-liquid ratios as low as 6-5:1 heading
into the overnight hours, particularly across the western zones. The
above thinking has resulted in another adjustment in the storm total
snowfall, with snow accumulations of up to 1 inch forecast along the
I-27/HWY-87 corridors. Total snow accumulations have also been
trimmed for the west-central South Plains and extreme southwestern
TX PH (generally along a line from Brownfield to Dimmitt) where snow
accumulations of 1-4" will be possible, and the greatest potential
for potentially significant snowfall remains across the southwestern
South Plains where 4-6" to locally 6"+ of snow is forecast. Due to
these adjustments, the Winter Storm Watch that was in effect for the
I-27/HWY-87 corridors will be converted into a Winter Weather
Advisory while the rest of the Winter Storm Warning is maintained
for now. Both the Winter Weather Advisory and Winter Storm Warning
will take effect at midnight CST tonight. Please reference the
discussion below for forecast details from Friday night into
Saturday involving this upcoming winter weather event.

Sincavage

&&

.LONG TERM...
(Friday night through next Wednesday)
Issued at 213 PM CST Thu Nov 24 2022

Our secondary chance of accumulating snowfall will come Friday
evening through Saturday morning as the upper low ejects northeast
across the Big Bend into central and north Texas. the initial source
of lift will be from the exit region of the upper level jet on
Friday evening but this will move off to the east on Saturday
morning. Q-vector convergence will maximize over the area before 12Z
Saturday and will favor the Rolling Plains before moving off. After
the large scale lift from the upper jet wanes, our primary source of
lift will be from the trowal region of the upper level system. Warm
and moist upglide within the trowal continues to be around the 300-
305K theta-e surfaces showing the best isentropic lift. Models
continue to show surface wet bulb temperatures warming above 0C
edging farther west. This would essentially cut into the snow totals
with more rain expected on the caprock. A rough line of the 0C Tw
value cuts from north to south approximately between the US385 and
US87 corridors. This would place Lubbock on the border of the
rain/snow line and may likely result in both precipitation types
throughout the evening and morning hours but favoring the liquid
type. A precipitation type of all snow is still favored near the
Texas/New Mexico state line into the western South Plains.

After 12Z Saturday as the system skirts east of the area, the last
precipitation chances will linger with moisture wrapping around the
system. Some of this precipitation could take the form of snow
across the central South Plains but will likely change over to rain
by late morning into the afternoon. With models also slowing the
system down a touch, precipitation will likely persist into the late
afternoon for areas off the caprock. Analog guidance indicates the
2004 election day winter storm and 2015 Christmas blizzard as top
analogs. However, a deeper dive into these cases reveals that
thermal profiles were generally colder than what is currently
forecast by model guidance. This would explain the discrepancy in
snowfall probabilities between the current forecast and analog
guidance.

Temperatures will warm for the next several days following this
winter system. A series of progressive short wave troughs moving
across the CONUS will generate surface lee troughing and downsloping
southwesterly winds causing the warm up. A stronger trough moving
across the central CONUS from Tuesday into Wednesday will send the
next cold front through sometime late Tuesday into early Wednesday
based on latest model guidance. Otherwise, a dry forecast is
expected through at least the middle of next week.

&&

.AVIATION...
(00Z TAFS)
Issued at 541 PM CST Thu Nov 24 2022

Not a good flying period at all for non-FIKI aircraft with
freezing levels at pattern altitude or lower with plenty of
supercooled water droplets to go around. Overall, with respect to
ceilings, we`ll probably be bouncing IFR to MVFR much of the
evening at KLBB/KPVW though some improvement is indicated late
tonight as the upper level low drifts to the southwest. However,
toward the end of the cycle, we should start to see the upper low
start moving northeast again causing another round of rain/low
ceilings/low viz.

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning from midnight tonight to noon CST Saturday
for TXZ021-022-027-028-033-034-039-040.

Winter Weather Advisory from midnight tonight to noon CST
Saturday for TXZ023-029-035-041.

&&

$$

SHORT TERM...09
LONG TERM....01
AVIATION...26



Area Forecast Discussion

National Weather Service Springfield MO

 540 PM CST Thu Nov 24 2022

Key Messages:

1. Rain and drizzle continues into tonight mainly along and south
of I-44.

2. Dry Friday then rain likely Saturday into Sunday morning.

3. Temps warming early next week with rain chances returning
Tuesday into Wednesday.

...AVIATION UPDATE...

.SHORT TERM...(This evening through Friday)
Issued at 145 PM CST Thu Nov 24 2022

Current Conditions and Synoptic Pattern: Early afternoon water
vapor imagery reveled several key features including an upper
level low across New Mexico with a feed of moisture curving up
into the Ozarks region. A shortwave trough was located over the
northern plains and was continuing to halt any eastward progress
of the southwest upper low. A surface trough and 850mb front were
pushing through the area with rain occuring east of Highway 65.
The western half of the area was mainly seeing drizzle as a 1230pm
aircraft sounding out of Tulsa, Ok revealed a loss of cloud ice
aloft. Clouds and precip have kept temps in the upper 40s to
around 50.

Drizzle/Rain This afternoon and evening: The 850mb front and
surface trough will not move very fast through the area. A
favorable north to northeast surface wind over the Ozark Plateau
will aid in continued drizzle and patchy fog development this
afternoon and evening. Additional rainfall amounts will remain
light and generally less than a tenth of an inch. After midnight,
a continued push of dry air into the area from the north should
allow for a decrease in clouds from the north with areas along and
north of I-44 dropping into the middle to upper 30s.

Dry Friday: Surface high pressure slides into Missouri with a
drier airmass building in. NBM and HREF data both support mostly
clear skies during the day which would support near average temps
in the lower to middle 50s with northerly winds.

.LONG TERM...(Friday Night through Thursday)
Issued at 145 PM CST Thu Nov 24 2022

Rainy Saturday-Early Sunday: The upper low will move out into
Texas and Oklahoma on Saturday, forcing an area of showers to move
overhead from late morning, lasting well into the evening. This
looks to be a widespread rain with rain chances greater than 90%.
A lack of cloud ice after dark may allow for more drizzle late
Saturday night into Sunday morning. Rainfall amount probs with
this system support a 60-80% chance of one inch of rainfall with a
95-100% chance of at least a half inch. Instability appears to be
too limited for any thunderstorms with chances less than 20
percent. High temps will also remain knocked down into the upper
40s to around 50.

Mainly dry Sunday Afternoon-Monday: Ensemble clusters support the
upper low opening up as it moves east of the area on Sunday. There
will be an additional shortwave that moves to the north of the
area during the day therefore clouds may linger into the
afternoon. A zonal flow aloft will persist through Monday with
clear skies and near average highs in the 50s.

Tuesday storm system: Ensembles are showing a upper level trough
 moving across the rockies and into the central Plains by Tuesday.
There continues to be variances in timing and location of the
trough, leading to a lower confidence forecast. At the moment it
appears a cold front will move through Tuesday night bringing a
chance of showers and thunderstorms. Ensembles are showing the
highest precip chances east of Highway 65 as moisture return ahead
of this system is in question a may favor areas further east.

There is support from the ECMWF Extreme Forecast Index and Shift
of Tails tool to suggest that this system bears watching from a
gusty wind potential as a strong surface low pressure brings in
30mph+ wind gusts. This system will be sampled by the upper air
network late in the weekend and we should see some consensus in
model data by then. Regardless, there is agreement that much
warmer temps (potentially 60s!) will occur ahead of the system on
Tuesday. Below average temperatures are becoming likely behind
this system for Wednesday and Thursday.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 526 PM CST Thu Nov 24 2022

While conditions at JLN will improve to MVFR at the beginning of
the TAF period, drizzle and fog will likely keep ceilings and
visibilities at IFR levels through at least 06Z at SGF and
particularly BBG where patchy fog may linger overnight. Conditions
look to improve to VFR levels by late Friday morning as the
surface front continues to shift east and high pressure moves into
the region.


&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

$$

SHORT TERM...Burchfield
LONG TERM...Burchfield
AVIATION...Didio