Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/21/23
Area Forecast Discussion
National Weather Service Amarillo TX
613 PM CDT Thu Apr 20 2023
...New AVIATION...
.SHORT TERM ...
(This evening through Friday night)
Issued at 303 PM CDT Thu Apr 20 2023
Northerly winds will be prevalent early this afternoon, but winds
are expected to turn westerly at least in the western counties
later this afternoon associated with a weak lee low moving through
the area. 30-35 mph winds are expected in western Deaf Smith
county, and 20-25 mph winds are possible elsewhere in the western
two rows of counties. Will be watching the trends through the
afternoon for when/where the winds in the southwest turn westerly
and strengthen. A Blowing Dust Advisory may be needed for at
least Deaf Smith county as strong winds in New Mexico that spill
into western Deaf Smith county may be a source for blowing dust
later today. With RH expected to be less than 10% in the area,
critical fire weather conditions is expected in the southwest.
Elsewhere, fuels and RH are dry enough such that even 15 mph
sustained winds would warrant a Red Flag Warning. Therefore, a Red
Flag Warning is in effect today for the combined Panhandles
except almost the entire southeastern half of the Texas Panhandle
counties.
A weak shortwave will move through the area this evening, but the
best forcing will exist in the north. Most guidance show at least
some weak showers in the Oklahoma Panhandles, though it`s rather
unimpressive. Forecast soundings show very dry low-levels with
sufficiently saturated mid-levels for at least clouds, if not some
rain to reach the surface. They also show some very weak elevated
instability which could produce a clap of thunder if instability
overachieves. If convective processes occur, then rain may be able
to make it to the surface. All that said, there`s very low
confidence whether the reflectivity, which looks weak anyway, will
make it to the surface. As such, 12z HRRR shows the weak
reflectivity but produces no QPF, so it appears that virga with
some gusty winds may be possible this evening. NBM spit out up to
55% PoPs which seems very aggressive considering the very dry low-
levels. Went with CONSShort to drop it below 20% in case
convective processes occur.
A reinforcing shot of cold air will follow the virga chances this
evening. With the cold/dense air behind the cold front moving from
the northwest (higher elevation) to the southeast (lower elevation),
won`t be surprised if the cold front comes in stronger, and perhaps
quicker, than the global models are showing. Indeed, 12z Mesoscale
models such as 12km/3km NAM show the northwest Panhandles
approaching the mid-20s while the global models are showing low-30s.
Winds are expected to back tomorrow to westerly, then to easterly
tomorrow evening as a lee low moves around the southwest edge of our
area. As the low moves off to the southeast tomorrow night, winds
will turn to some northerly wind component with another shot of cool
air from the north. Winds could get breezy late in this short-term
period with some decent pressure rises and tightening pressure
gradients.
FIRE WEATHER... Critical fire weather is expected this afternoon
in the combined Panhandles excluding the southeastern Texas
Panhandle and Lipscomb county. 30-35 mph sustained westerly winds
with gusts up to 40 mph are expected in Deaf Smith county where RH
will be 7-10%, leading to RFTI of 7-8 later this afternoon.
Elsewhere... 15-25 mph winds are expected, but extremely dry fuels
with low RH allows Red Flag Warning criteria to be met. A cold
front push in from the northwest this evening, switching winds to
northerly. After this evening, very little to no fire weather is
expected through the next week.
Vanden Bosch
&&
.LONG TERM ...
(Saturday through next Wednesday)
Issued at 303 PM CDT Thu Apr 20 2023
Below normal temperatures are expected for most, if not all, of
the long term periods Saturday through Thursday due to additional
reinforcing cool air surges plus cloud cover and chances for
precipitation. A couple minor upper level shortwave trofs
embedded in the WNW flow aloft will impact the forecast area
Saturday night through Sunday night and will bring a threat for
showers. Perhaps a bit of light rain and light snow mix may occur
across far northwest sections and the OK Panhandle late Saturday
night and Sunday morning. However, the probability of this
occurring is low, and the majority of the precipitation is
expected to fall in the form of light rain showers across the area
Saturday night through Sunday night.
For Monday through Thursday, an upper level trof of low pressure
system, possibly a closed low at times, is expected to develop
around the four corners region by Monday morning, then slowly
track eastward across the southern high plains region by Wednesday
afternoon. Medium range models continue to differ on rainfall
amounts, track, and whether or not a closed low develops. Given
continued medium range discrepancies, believe a consensus approach
is necessary this far out in time, with details refined as time
gets closer. Dry weather returns next Thursday. For this package,
have incorporated the NBM temperatures and pops for all long term
periods. Expect further adjustments to the forecast during the
coming days as models begin to converge on a more common solution.
02
&&
.AVIATION...
(00Z TAFS)
Issued at 611 PM CDT Thu Apr 20 2023
VFR conditions should prevail through the period at all TAF sites.
Winds will tend to be around 15 knots or less and generally out of
the north or west, although Amarillo could see some winds out of
the south over the next few hours.
Ferguson
&&
.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX 37 69 40 61 / 10 0 0 0
Beaver OK 36 66 37 57 / 10 0 0 0
Boise City OK 28 64 33 54 / 10 0 0 0
Borger TX 38 70 41 61 / 10 0 0 0
Boys Ranch TX 35 69 40 61 / 10 0 0 0
Canyon TX 36 70 40 62 / 10 0 0 0
Clarendon TX 42 69 43 61 / 10 10 0 0
Dalhart TX 28 66 34 56 / 10 0 0 0
Guymon OK 33 66 36 57 / 10 0 0 0
Hereford TX 35 71 40 63 / 10 0 0 0
Lipscomb TX 36 67 39 56 / 10 0 0 0
Pampa TX 37 67 40 57 / 10 0 0 0
Shamrock TX 40 69 42 61 / 10 10 0 0
Wellington TX 43 71 42 63 / 10 10 0 0
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...Red Flag Warning until 10 PM CDT this evening for TXZ001>004-
006>008-011-012-016-017-317.
Freeze Warning from 3 AM to 9 AM CDT Friday for TXZ001-002-006.
OK...Red Flag Warning until 10 PM CDT this evening for OKZ001>003.
Freeze Warning from 3 AM to 9 AM CDT Friday for OKZ001-002.
&&
$$
SHORT TERM...52
LONG TERM....02
AVIATION...77
Area Forecast Discussion
National Weather Service Burlington VT
1009 PM EDT Thu Apr 20 2023
.SYNOPSIS...
A warm front will lift across the region tonight with increasing
clouds and a spot shower or two possible near the International
Border after midnight. Much warmer temperatures return on Friday
with developing southerly winds. A few additional showers are
possible on Friday night across northern New York, before a mostly
dry Saturday is on tap. A widespread rainfall is anticipated on
Sunday with cooler temperatures. This trend of cooler and unsettled
weather prevails into early next week.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
As of 1005 PM EDT Thursday...Cloud cover continues to overspread
the region but is a tad quicker than previously forecast. This
has led to temperatures remaining steady over the past few hours
with the only the Northeast Kingdom experiencing a traditional
radiational cooling night thus far. Temperatures may dip a few
degrees through the overnight hours but given the latest LAPS
and RAP analysis, the 850 ad 925 mb 0 degree isotherm is lifting
north which is a sign warm air advection should be kicking in
soon. Once winds shift to the south toward daybreak, a steady
warming trend is then expected. A few showers remain possible
through the overnight hours but given the lack of cooling thus
far, a 15 to 20 degree dewpoint depression has been observed at
the surface. This will make it hard for precip to make it to the
ground and any precip that does will in turn be light.
Previous Discussion...Water vapor this aftn shows deep dry
layer acrs the ne conus with ribbon of mid lvl moisture acrs the
Great Lakes associated with a warm frnt. This boundary wl be lifting
acrs our region overnight, while weak embedded 5h vort slides along
the International Border toward 06z. The best combination of mid lvl
moisture and forcing wl be located acrs our extreme northern cwa
into the NEK of VT, so have 15 to 20% pops in this region mainly
btwn 04z-10z. Temps are challenging with increasing waa after 06z,
especially western cwa, along with some increasing mid lvl clouds.
Thinking we drop early back into the 30s to near 40F, before warming
after midnight from a combination of increasing southerly flow and
more clouds. Coolest values of upper 20s wl be acrs the NEK where
they are struggling to reach 40F as of 200 PM this aftn.
Friday the focus wl be temps again, followed by a slight chc of a
spot shower toward 00z Saturday. Little change has been noted with
regards to our complex thermal profiles on Friday with warmest 925mb
temps of near 20F acrs the southern SLV/western Dacks, while values
struggle in the 8-10C associated with east-southeast llvl flow east
of the Greens. Have kept temps very similar to previous fcst with
highs ranging from the upper 50s/lower 60s NEK to upper 70s/lower
80s western Dacks. Several CAM such as the HRRR/NAM 3KM and RAP are
indicating some weak showers possible on Friday evening associated
with llvl convergence on ne flow down the SLV and
southwest/southeast acrs the western Dacks. In addition, sfc heating
and some return bl moisture, helps to produce a weak axis of CAPE
with values btwn 250 and 500 J/kg by 21z Friday. Have continued with
low prob of a shower or rumble of thunder toward 00z Sat and
continuing into the overnight hours. The primary threat wl shift
north of our International Border area by 12z Saturday. Temps with
increasing southerly flow ahead of approaching trof should remain in
the upper 40s to lower 50s SLV/CPV, while cool back into the upper
30s to mid 40s east of the Greens.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
As of 301 PM EDT Thursday...Saturday will start out mainly dry with
increasing chances for rain showers in the afternoon across our
Northern New York zones. Our region will be under warm southerly
flow ahead of the front, and temperatures will reach the mid 50s
across eastern Vermont, with upper 60s to lower 70s from the
Champlain valley westward. South southeasterly gusty winds are
expected as a 40 kt 925 mb jet crosses the region. Cold front will
push into the region Saturday night, and rain will spread across our
area. Temperatures on Saturday night will remain mild, only dipping
into the upper 30s to upper 40s, coldest in the Northeast Kingdom.
Winds will remain brisk out of the southeast, starting to let up
towards early Sunday morning.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 301 PM EDT Thursday...Showers will be slow to exit our region
on Sunday, with rain continuing into the day. Surface front stalls
out over the region, and upper level low is extremely slow to cross
the region. Sunday night through Tuesday will remain pretty
unsettled as upper level low takes a very long time to finally move
out of our region. Plenty of clouds and precipitation through the
first half of the week at least, means below normal temperatures
along with wet weather is anticipated. Models continue to show some
drier warmer weather towards the end of next week.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
Through 00Z Saturday...VFR conditions are expected to continue
through the TAF period with mid to high level clouds expected to
traverse the North Country. While a few rain showers may be
possible for northern Terminals, dry air in place at the surface
should prevent any reduction in visibilities. Northerly winds
this evening will go light and variable overnight and begin to
pick up from the south by 12Z on Friday. Winds are expected to
top out around 10 knots but a few gusts up to 15 to 18 knots may
be briefly seen in the Champlain Valley Friday late afternoon.
Outlook...
Friday Night: VFR. Chance SHRA.
Saturday: Mainly VFR, with local MVFR possible. Slight chance
SHRA.
Saturday Night: Mainly VFR, with areas MVFR possible. Definite
SHRA.
Sunday: Mainly MVFR, with areas VFR possible. Definite SHRA.
Sunday Night: Mainly MVFR, with local IFR possible. Likely SHRA.
Monday: Mainly IFR, with areas MVFR possible. Likely SHRA.
Monday Night: Mainly IFR, with areas MVFR possible. Chance SHRA.
Tuesday: Mainly MVFR, with areas IFR possible. Chance SHRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Taber
NEAR TERM...Clay/Taber
SHORT TERM...Neiles
LONG TERM...Neiles
AVIATION...Clay
Area Forecast Discussion
National Weather Service Columbia SC
744 PM EDT Thu Apr 20 2023
.SYNOPSIS...
Dry high pressure and above normal temperatures will continue
through Friday. Saturday will see a cold front moving through
the region, bringing showers and possibly a few thunderstorms
along with it. Cooler temperatures return for Sunday into early
next week. The next chance for precipitation arrives midweek.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Some shallow moisture will creep back into the forecast area
tonight with surface high pressure to our east. There is some
potential for fog development tonight with mostly clear skies
and light winds. However, thin cirrus, a 20 kt low level jet,
and low crossover temperatures should prevent widespread fog.
The area of greatest concern for fog development will be nearer
the coastal plain where a sea breeze has allowed dewpoints to
bump up a few degrees and also in fog prone areas. The HRRR
adds confidence indicating lower visibilities to the east and
along rivers. Low temperatures will generally be in the mid
50s.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
Friday and Friday night: The surface high will be pushing
further away from the coast on Friday, but will still be close
enough to influence our weather. This will result in one more
dry day across the cwa on Friday, with afternoon highs
continuing to be above normal in the mid 80s. By Friday night,
moisture will be on the increase as moisture moves inland from
the Atlantic. This increase will help moderate overnight lows
Friday night, with readings in the lower 60s expected.
Saturday and Saturday night: The main cold front will be just
off to the west of the forecast area to start off the day. There
may be a few light showers or sprinkles going on during the
morning, but as the front moves in, rainfall coverage will
increase by late morning into the afternoon. Main activity
should remain showers, but there should still be enough
instability by the afternoon for a few thunderstorms to develop
along the cold front. Based on the timing of the front, the best
chance for stronger storms would be over the eastern most
portions of the cwa later in the afternoon. SPC has eastern cwa
in a Marginal Risk, and keeps the Slight risk further east along
the coast. Primary threat would be stronger winds in the heavier
showers/storms. In addition through the day, surface winds will
be somewhat stronger. Will continue to monitor since a need for
a Lake Wind Advisory can not be ruled out. With some increase in
cloud cover, daytime temperatures will cool ever so slightly.
Readings will top out in the upper 70s to lower 80s. By Saturday
evening, the front moves east and cooler and drier air moves in
behind the front.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
Behind the front, Sunday will be dry and slightly cooler.
Readings drop into the mid to upper 70s through the day, with
lighter winds and a good amount of sunshine expected. The dry
weather will continue through Tuesday, with the next chance for
any rainfall not expected until possibly Tuesday night through
Thursday.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
Mainly VFR conditions. MVFR fog forecast at AGS/OGB early
morning.
With the pressure ridge centered along the coast, the low level
flow will be southeast to south. This will result in slight
increase in low-level moisture. The sea breeze moved into the
southeast Midlands SC this afternoon and dew points are a tad
higher from OGB to AGS. The latest HRRR model is suggesting a
threat for some patchy fog mainly in the southeast Midlands...so
added MVFR fog to OGB and continued forecast MVFR fog at AGS.
Otherwise mainly clear through late Friday morning. High based
cumulus possible after 18z Friday. South winds Friday afternoon
around 10 knots with a few higher gusts.
EXTENDED AVIATION OUTLOOK...Restrictions possible late Friday
night and Saturday as a cold front along with showers and
thunderstorms crosses the region.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Cheyenne WY
512 PM MDT Thu Apr 20 2023
.SHORT TERM...(Late this afternoon through Saturday night)
Issued at 355 PM MDT Thu Apr 20 2023
A broad upper low extended from eastern MT into the western Dakotas
with a fast shortwave-laden northwesterly flow aloft over southeast
WY and western NE. Low level convergence along a surface trough
bisecting the CWA from west to east combined with steep low/mid level
lapse rates resulted in marginal instability for scattered rain/snow
showers. MUCAPES up to 100 j/kg may trigger a few lightning strikes
with the heavier showers. Per the latest HRRR guidance, this
convective activity will continue until early evening then decrease
in coverage with stabilizing environment. Gusty west to northwest
winds of 35 to 50 MPH will diminish this evening, before increasing
once again overnight tonight.
A persistent northwesterly flow aloft between a mean trough over the
central/eastern CONUS and ridge over the Intermountain West will be
the dominant feature. Embedded shortwaves and fairly steep low/mid
level lapse rates will aid in the development of scattered to numerous
rain and/or snow showers over much of southeast WY. Isolated thunder
will be possible over Carbon County Friday afternoon/early evening
with MUCAPEs up to 100 j/kg. Strong orographic flow will produce
moderate to locally heavy snow accumulations over the Snowy/Sierra
Madre Ranges Friday morning through Saturday morning. Accumulations
of 6 to 12 inches are expected, with locally higher totals above
9500 feet. Gusty winds Friday will produce poor visibility in blowing
snow. Winter Weather Advisories remain in effect. The Laramie Range
and northern Carbon County can expect 2 to 5 inches, with 1 to 2
inches in the adjacent valleys and foothills. Friday will be the
windiest day of the short term as a band of 55-65 kt 700-800mb flow
is oriented northwest to southeast from eastern WY into western NE.
West to northwest winds will gust between 45 and 55 MPH. Winds will
be lighter Saturday as the axis of stronger winds aloft shifts further
east. 700mb temperatures will range from -6 to -12 degrees Celsius
through Saturday, supportive of the unseasonably cool temperatures
for late April. High temperatures Friday and Saturday will be in the
30s and 40s.
.LONG TERM...(Sunday through Thursday)
Issued at 355 PM MDT Thu Apr 20 2023
The unsettled weather pattern will continue through much of the week
ahead. The main focus of this forecast is the potential for a stronger
upper level low to swing through in the Tuesday/Wednesday time frame
next week.
Starting off on Sunday, we will have a broad trough sitting over the
Great Lakes with northwest flow transitioning to more zonal as a
very subtle ridge tries to come in over the Rockies. This will
initiate weak warm air advection, with GEFS mean 700-mb temperatures
at KCYS climbing from -8C at 00z Sunday to around -3C to 00z Monday,
and perhaps above 0C by 00z Tuesday. This warmup will be weaker and
more transient than the last few, with continued pulses of vort maxes
moving through the flow keeping things unsettled. While Sunday should
be mostly dry, a weak vort max moving through may be enough to pulse
up some light snow showers in the mountains, and some virga showers
over the high plains. Temperatures should climb closer to normal with
most areas in the upper 40s to 50s, and some 60s showing up in the
usual warm spots. Monday looks a little warmer, likely the warmest
day of the long term period. We`ll climb slightly above average, with
most areas east of the Laramie range reaching the 60s, and 50s to
the west. With split flow over the western CONUS and a surface high
over the northern plains, synoptic winds should be on the lighter
side, though can`t rule out gusty winds with any pulse type showers
that manage to get going.
Later on Monday, we may start to see some impacts from the next
system, though considerable uncertainty remains with this one. The
synoptic stage will be set by a more vigorous upper level shortwave
diving down across the Rockies out of the northwest as a stronger
ridge builds into the west coast. Models remain sharply divergent,
with little movement from either camp in the last 24 hours or so.
The GFS has a weaker, more progressive upper level low, while the
ECMWF brings a much slower, stronger low and manages to close it off
from the flow. However, the ECMWF has been trending south with the
cutoff low, now putting most of the QPF to our south, though some
impacts would stretch into the I-80 corridor in this scenario.
Ensembles don`t provide too much help, with each system firmly
following the deterministic counterpart. GEFS members are all more
progressive and further north, while ECE members are all slower and
further south. The system also looks rather disorganized with
chances for showery precipitation from Monday afternoon through
Wednesday (accounting for the possibility of the slower solution).
As is typical this time of year, getting this properly represented
in the gridded forecast was pretty tricky, since the ensemble mean
temperature forecast is not exactly consistent with the need to
mention the >20% probability for snow in some areas. For example,
both the deterministic GFS and ECMWF have easterly flow at 700-mb
over the high plains by Tuesday afternoon, indicating the potential
for deep upslope flow. 1000 to 500-mb thickness on both models is
under 552-dm which is typically sufficient to produce mainly snow
about about 5 or 6 kft elevation. The actual temperature and
precipitation type outcome on Tuesday across the area will likely be
determined by the precipitation rate, which is still highly uncertain
at a 5-day lead time. Thus for areas east of the Laramie range, went
with the minimum snow level from available guidance, and dropped
surface temperatures for a few hours Tuesday afternoon to account
for the possibility of heavier precip rates changing over to snow
faster than a pure model blend would show. As we get closer, the
precipitation rates will come into better focus and we will have a
better idea of exact snow levels and temperatures. But, with a closed,
vertically stacked low located to our south, a warm rain scenario
seems unlikely in April, at least for the higher elevations.
Beyond this system, models show an amplified ridge pushing into the
west coast, but with our area somewhat on the periphery. Both the
GFS and ECMWF are fairly consistent with one another showing an odd
looking upper level low diving nearly due south out of the Canadian
prairie and bringing another round of precipitation to the area.
Therefore, low end PoPs are present in the forecast for the vast
majority of the period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 508 PM MDT Thu Apr 20 2023
Scattered light to moderate rain/snow showers are continuing
across southeast Wyoming and western Nebraska this
afternoon/evening causing briefly MVFR to IFR conditions and gusty
west to northwesterly winds. These showers should mostly end near
to just after sunset (02Z to 03Z), but gusty west to northwest
winds will continue overnight. Another round of snow showers are
likely tomorrow moving in from the west. KRWL will be the first to
be affected with CIGS and VIS dropping to IFR, even potentially
LIFR.
&&
.FIRE WEATHER...
Issued at 420 AM MDT Thu Apr 20 2023
Cooler temperatures & daily chances for precipitation should limit
overall fire weather concerns through the weekend. Breezy, locally
windy conditions with gusts 45-55 MPH at times may support chances
for fire growth with any new starts, but RH values are expected to
remain outside of critical thresholds.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Winter Weather Advisory from 9 AM Friday to 9 AM MDT Saturday
for WYZ112-114.
NE...None.
&&
$$
SHORT TERM...MAJ
LONG TERM...MN
AVIATION...LK
FIRE WEATHER...CLH
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1021 PM CDT Thu Apr 20 2023
...New UPDATE...
.UPDATE...
Issued at 1010 PM CDT Thu Apr 20 2023
Severe Thunderstorm Watch 155 expired at 10 PM, but there are still a
couple of strong to severe storms moving across the area. There is
still some chance for severe storms for a few more hours, but the
probabilities are decreasing. Severe Thunderstorm Watch 156 remains
in effect over the southeastern counties until 2 AM.
&&
.UPDATE...
Issued at 825 PM CDT Thu Apr 20 2023
We have replaced one Severe Thunderstorm Watch with a new one for
Gonzales, Fayette, Karnes, De Witt, and Lavaca Counties that will go
until 2 AM. The earlier Watch remains in effect elsewhere until 10
PM. Storms will linger a little longer over the southeast.
&&
.SHORT TERM...
(Tonight through Friday night)
Issued at 1242 PM CDT Thu Apr 20 2023
Mostly cloudy skies and southerly winds prevail across the area
early this afternoon. Temperatures are in the lower 80s across most
locations with some shower activity noted near Bexar County and east
of the I35 corridor. Aircraft soundings from AUS show a decent cap
that remains near 725 mb and this is likely preventing deep updrafts
from occurring. However, the HRRR continues to want to strengthen
this activity later today which likely points to the cap either
eroding or surface temperatures warming beyond the point where the
cap matters. The storm environment is unstable this afternoon with
CAPE values approaching 3000 J/kg. Effective bulk shear is near 30
knots which would support some severe threat if deep convection
becomes established. The main threats this afternoon would be hail
and damaging winds as helicity values are low.
The attention after the afternoon activity then focuses on a
potential line of showers and storms along a boundary to our
northwest. Morning high-res guidance shows this activity moving
through the CWA late this afternoon through the evening hours from
northwest to southeast. Guidance has shown a bit higher coverage of
activity to the west and the latest Day 1 Outlook from SPC accounts
for this with the slight risk now almost to the Rio Grande. Large
hail and damaging winds will continue to be the main risks for
severe convection. Low-level winds pick up slightly this evening,
and while we can`t completely rule out a tornado or two, overall
chances are low. Rainfall amounts for most locations will average
below an inch, but some spots may pick up 1-3 inches with isolated
higher amounts. This could lead to a localized minor flooding threat
from the heavier totals.
Most of the shower and thunderstorm activity will push east of the
area by 1 AM. Lows tonight will be in the 60s. There could be a few
residual showers or storms in the east tomorrow morning, but
otherwise, a dry Friday is expected with highs ranging from the
lower 80s in the northeast to the lower 90s in the southwest. Mostly
clear skies and lows in the 50s to lower 60s returns Friday night.
&&
.LONG TERM...
(Saturday through Thursday)
Issued at 1242 PM CDT Thu Apr 20 2023
Synopsis: Behind Friday`s departed cold front, predominantly west to
northwest flow will prevail in the mid and upper levels through the
majority of the period. Conditions will remain unsettled, with
mentionable precipitation probabilities and shower/storm mentions
remaining in the forecast through the middle portions of next week.
While each day won`t feature severe thunderstorm potential, an
isolated strong to severe storm can`t be ruled out from San Antonio
and points westward on Saturday. Largely southerly to southeasterly
925-850 mb flow will prevail Sunday and Monday, bringing plenty of
Gulf moisture northward atop of a cooler boundary layer under the
influence of easterly winds. This will help to drive additional
precipitation chances through the beginning of next week. An upper
disturbance is forecast to eject from the central Rocky Mountains on
Tuesday, encouraging surface cyclogenesis to our north in the Texas
Panhandle/Red River vicinity. This will place the majority of South-
Central Texas to the east of a sharpening dryline. The combination
of the advancing dryline and favorable forcing aloft could support
more vigorous thunderstorm development during this portion of the
period. While still six days out, it`s possible that some of this
activity could become strong to severe.
Saturday: Winds will be quick to turn southeasterly behind the
Friday cold front, bringing moisture and attendant instability
quickly back into portions of the area. Guidance continues to
suggest that the greatest instability will pool over our
southwestern zones, where as much as 1000-1500 J/kg of CAPE could
materialize in the mixed layer. The combination of said instability
and sufficient shear aloft could support some better-organized
convection during the afternoon hours. It`s possible that some of
said activity could reach marginally severe levels, with large hail
and damaging winds being the primary concerns. The Storm Prediction
Center thus continues to include the majority of the southern
Edwards Plateau, Rio Grande Plains, and portions of western Hill
Country (including the city of San Antonio) in a marginal (level
1/5) risk for severe weather in its day three convective outlook.
Sunday Through Monday: Thanks to continued low level moistening, and
the jet stream in place overhead, shower activity will continue.
Whether thunderstorms mix in with the showers remains uncertain. The
global ensembles disagree regarding the amount of instability
available for storms on each afternoon, with GEFS members coming in
considerably more aggressive than their ECMWF counterparts. Trends
regarding instability will need to be monitored in the coming
forecast cycles, as ample deep layer wind shear would support some
potential for stronger thunderstorms during this portion of the
period. As things currently stand, predominantly rain showers and
isolated non-severe thunderstorms are expected through this portion
of the period.
Tuesday: More robust thunderstorm activity is possible along and
east of an advancing surface dryline during the afternoon hours,
particularly as the shortwave discussed in the synopsis begins to
eject into the Southern Plains. The combination of lift provided by
the dryline/approaching wave, ample instability, and sufficient bulk
shear would likely support some strong to severe storm potential,
particularly if the best forcing arrives during peak heating. Given
uncertainties regarding said timing, it`s much too early to offer
any specifics regarding potential hazards. SPC has introduced a 15%
risk area for severe thunderstorms across most of South-Central
Texas in light of this potential.
Remainder Of The Period: Isolated storms could persist across the
far northeast on Wednesday, but it appears a drying trend will begin
to establish itself by late next week/the conclusion of the long
term period.
&&
.AVIATION...
(00Z TAFS)
Issued at 622 PM CDT Thu Apr 20 2023
Greatest aviation concerns will be with strong to severe convection
across the region from this evening into the early overnight hour. A
severe storm is approaching KSAT from the west and a line of storms
are congealing across the Hill Country and will approach the I-35
corridor, including KAUS, KSAT and KSSF later tonight. Storms will
remain capable of hail, strong winds, heavy rain and frequent cloud-
to-ground lightning. Storms will likely lead to lowered visibility
and ceilings as well into the IFR to MVFR range. Highlighted a tempo
group for when the heaviest storms are expected to impact the TAF
sites. As storms have moved out of the area, winds will turn out of
the north with moderate to breezy winds following in wake of the
boundary. Additionally, expect for ceilings at the I-35 TAF sites to
lower through the overnight into early Friday morning to the MVFR
to VFR range. Conditions will improve to VFR into Thursday afternoon
with clearing skies.
KDRT will remain VFR through most of the night with all the storms
remaining farther to the east. MVFR ceilings develop late overnight
into Friday morning before conditions return to VFR into Monday
afternoon with clearing skies.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 65 82 54 80 / 80 20 0 10
Austin Bergstrom Intl Airport 64 81 53 78 / 70 20 0 10
New Braunfels Muni Airport 67 84 55 81 / 70 10 0 10
Burnet Muni Airport 62 79 52 78 / 80 10 0 10
Del Rio Intl Airport 69 91 61 89 / 10 0 0 10
Georgetown Muni Airport 63 79 52 77 / 90 20 0 10
Hondo Muni Airport 67 86 56 81 / 40 10 0 10
San Marcos Muni Airport 66 82 54 79 / 70 10 0 10
La Grange - Fayette Regional 67 79 53 78 / 70 20 0 0
San Antonio Intl Airport 67 84 57 80 / 70 10 0 10
Stinson Muni Airport 69 86 58 82 / 60 10 0 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term...05
Long-Term...29
Aviation...Brady
Area Forecast Discussion
National Weather Service Shreveport LA
913 PM CDT Thu Apr 20 2023
...New UPDATE, SHORT TERM...
.UPDATE...
Issued at 904 PM CDT Thu Apr 20 2023
Canceled some of SVR 153, while extending the rest, some of which
are overlapped by the new SVR 156 that continues until 2AM.
&&
.SHORT TERM...
(Tonight through Friday Night)
Issued at 904 PM CDT Thu Apr 20 2023
Not much change to the going forecast aside from subtracting some
cleared counties and extending others until 11PM for 153, along
with adding the new Severe Thunderstorm Watch 156 for deep E TX
and Toledo Bend country until 2AM. We are seeing much more than
the HRRR has been handling at least for NW LA where a hole of
potential has looming since this afternoon`s progs. Looks like
much of our area will get wet and some of it too wet with the slow
movement. Stay tuned overnight as this event continues to unfold
with perhaps less severe and more flooding possible as all this
continues to slowly work across our four state area. /24/
&&
.LONG TERM...(Saturday through next Wednesday) Issued at 232 PM
CDT Thu Apr 20 2023
A post frontal airmass will be in place across the Arklatex
Saturday featuring sunrise temperatures in the upper 40s to around
50 degrees and afternoon highs in the 70s. Dew points in the 40s
and a light east to northeast wind should result in a pleasant
day before more rain returns for the later half of the weekend.
Weak northwest flow will set up across the region Sunday. A weak
midlevel disturbance tracking out of the Southern Plains should be
enough to result in showers and a few thunderstorms, mainly
across McCurtain county Oklahoma into southwest Arkansas. A
transient ridge may result in a brief break in the showers and
thunderstorms early in the weak, but southwest flow will return by
midweek in response to a deepening trough over the southern
Rockies. Dew points will briefly return to the middle 50s to mid
60s by midweek with showers and thunderstorms expected each day.
Conditions do not look supportive of severe thunderstorms.
Rainfall totals Saturday through midweek are expected to be in the
1.5 to 3 inch range. Another cold front is expected after midweek
resulting in slightly cooler temperatures and diminishing rain
chances. 30/Sirmon
&&
.AVIATION...
(00Z TAFS)
Issued at 646 PM CDT Thu Apr 20 2023
For the ArkLaTex terminals, long night ahead with storms arriving
now at KTYR/KTXK. All terminals will see a window of weather and
wind ahead of our next fropa. Southerly winds will begin to shift
to N/NW 10-20KT at KTXK before daybreak and then our I-20
terminals from KTYR/KGGG by 15Z to KSHV/KLFK not long after and
then KELD depending on the convection ahead of the boundary. KMLU
will have to wait until around 18Z. So, TS overnight and then
IFR/MVFR cigs from daybreak until early aftn, then SKC. /24/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 65 75 51 76 / 80 60 0 0
MLU 65 75 49 76 / 90 80 10 0
DEQ 56 73 46 73 / 80 50 0 0
TXK 62 74 49 75 / 80 50 0 0
ELD 62 72 47 74 / 80 70 0 0
TYR 61 74 50 76 / 80 50 0 0
GGG 63 75 49 76 / 80 50 0 0
LFK 64 78 52 79 / 80 50 0 0
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
SHORT TERM...24
LONG TERM....30
AVIATION...24