Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/11/19
Area Forecast Discussion...UPDATED
National Weather Service Amarillo TX
703 PM CDT Fri May 10 2019
For the 00Z TAFs, MVFR cigs will persist through this evening,
eventually becoming IFR late tonight into mid morning Saturday at
the terminal sites. Cigs should improve to VFR around mid afternoon
.PREV DISCUSSION... /Issued 257 PM CDT Fri May 10 2019/
SHORT TERM...Today and Tonight...
Light rain showers are beginning to fill in the southwestern Texas
Panhandle and will continue to progress northeast through the
afternoon. Light snow is possible mainly in the far western
Panhandles where temperatures remain in the mid to upper 30s. No
accumulations are expected to occur with any light snowfall. Cloudy
skies will persist all day today and through the morning hours
Saturday. A shortwave trough will be over the central Rockies
tonight and continue to provide light rain showers across the
eastern half of the Panhandles. Meanwhile, the RAP 500mb heights and
midlevel GOES16 satellite water vapor shows a midlevel closed low
over the south central coast of California and is in agreement with
all the models. Temperatures tonight will be slightly warmer ranging
from the upper 30s in the northwest Texas and Oklahoma Panhandles to
the upper 40s in the southeast Texas Panhandle.
LONG TERM...Saturday through Friday...
Fairly uneventful forecast with chances for showers and non-severe
thunderstorms through Monday night, followed by dry weather
through Thursday night. Potential for severe thunderstorms to
Models and ensembles have maintained their depiction of evolution
existing split flow. Closed mid-level low in southern stream
over central California today retrogrades into Pacific before
coming ashore early Saturday evening north of the Baja spur.
Steady eastward movement of closed low across northern Mexico will
continue through Sunday night. By late afternoon Monday system
crosses Rio Grande and moves close to Midland. Circulation wanes
Monday night and Tuesday with system becoming an open positively-
tilted wave which clears the southeast Texas Panhandle Tuesday
Meanwhile, Texas and Oklahoma Panhandles will be influenced by
northern stream trof Saturday and Saturday evening. Main trof axis
passes Saturday evening, with northwest flow aloft then prevailing
through Sunday evening. Flow weakens Monday and Monday night as
remnants of aforementioned southern stream system are absorbed.
Modest amounts of moisture and instability warrants mention of
showers and thunderstorms Saturday through Monday night, with
southern sections generally favored, owing to expected higher
amounts of moisture being available.
Ridge builds across Rockies Tuesday through Wednesday, with
northwest flow across the Panhandles. Ridge moves across Panhandles
Thursday and Thursday night. By Friday morning, a digging trof
emerges from the eastern Pacific. Strengthening southwest flow on
Friday will likely lead to increasing chances for organized and
possibly severe thunderstorms through the weekend.
Area Forecast Discussion...UPDATED
National Weather Service Austin/San Antonio TX
825 PM CDT Fri May 10 2019
Seeing an uptick in elevated convection this evening across just to
the east and south of San Antonio as well as across far northern
areas of the CWA. Models did not capture this activity south and east
of San Antonio well, and have updated forecast to raise PoPs through
the evening across this region as it continues to expand and lift
northeast. MUCAPE values near 1000 J/kg supporting a few stronger
updrafts with lightning occurring in this activity. MRMS has been
estimating pockets of rainfall rates nearing 1" per hour.
Recent runs of the HRRR as well as Texas Tech 4 KM show increasing
coverage of showers across western areas of the CWA between Midnight-
3AM as main forcing comes out of Mexico, then expanding into central
areas of the CWA/I-35 corridor between 3AM-6AM, then east of the I-35
corridor through Saturday morning. Have increased PoPs slightly in
some areas to account for this.
We will maintain the Flash Flood Watch for the time being. As
mentioned in previous forecast this is highly conditional on seeing
expanding coverage of elevated convection overnight. If this does
occur, some pockets of rainfall up to 1 inch could be possible (as
evident with current rainfall rates mentioned above that are ongoing
this evening). Very difficult to pinpoint where these pockets could
occur, but out of abundance of caution the Flash Flood Watch will
remain in place given some locations that are currently very
sensitive to any additional rainfall resulting in very quick runoff.
.PREV DISCUSSION... /ISSUED 648 PM CDT Fri May 10 2019/
AVIATION... /00Z TAFS/
CAMS models show a minimal amount of deep layer convection affecting
the I-35 terminals this evening, so have pulled back on the VCTS and
favored the best chance of thunder to be 09Z to 12Z to reflect recent
HRRR and NAM runs. Expect a gradual descent of low cigs to ifr toward
midnight with a few pockets of lifr conditions by 09Z. Meanwhile at
DRT shower activity looks minimal for the evening with model
consensus showing mainly showers possible from 06Z to shortly after
daybreak. Subsidence could work its way into this area at daybreak,
so some brief vlifr conditions may need to be considered in later
updates. A slow improving trend is expected through midday, with all
the low level moisture expected to keep a prevailing mvfr cig
through the daytime hours along I-35.
PREV DISCUSSION... /ISSUED 342 PM CDT Fri May 10 2019/
SHORT TERM (Tonight through Saturday Night)...
Conditions are expected to begin gradually trending drier for South
Central Texas in the short term portion of the forecast. A few
showers have been able to develop across the Rio Grande Plains this
afternoon and into the Edwards Plateau, but most areas will not see
rain through the early evening hours. SPC Mesoanalysis this afternoon
shows a mid-level wind speed maxima associated with a disturbance
over northern Mexico lifting into Southwest Texas. As this speed max
lifts farther to the northeast, reaching the Rio Grande Plains,
scattered showers and thunderstorms are expected to develop across
the Edwards Plateau and Hill Country late this evening or early
Saturday morning. Despite a stable boundary layer behind yesterday`s
cold front, over 1000 J/kg of MUCAPE, long, skinny CAPE profiles
(encouraging water loading of updrafts), and forecast precipitable
water values near 1.5 inches per forecast soundings from Austin and
Waco, will allow for a locally heavy rain threat to linger with
overnight storms. The tricky aspect will be where these actually
develop as model guidance has placed an axis of higher 1-1.5 inch
rainfall amounts anywhere from the I-35 corridor to the Hill Country
to north of Waco throughout the day.
Based on lower flash flood guidance values and their proximity to
this potential higher rainfall axis, Burnet, Williamson, Blanco,
Travis, and Hays all appear to have at least some threat for isolated
minor or flash flooding overnight. This is highly contingent on how
close to the region this higher rainfall axis is able to develop,
however. Additional attention will have to be paid to the stalled
frontal boundary located along the Middle Texas Coast and bisecting
the Houston metro as increasing forcing for ascent results in another
thunderstorm complex developing close towards the Texas coast by
Saturday morning. While this boundary is expected to stay just east
of the region through Saturday night, will also have to watch for a
secondary heavy rain threat for the Coastal Plains counties in case
any kind of convective interaction with the front (outflow/cold pool
development) nudges it closer to the region. The passage of the
disturbance from Mexico should allow for rain to end from west to
east during the day on Saturday, with Saturday afternoon activities
for most of the region likely dry.
Regarding the Flash Flood Watch, have opted to continue it with a
(highly) conditional threat for additional rainfall overnight. As was
noted earlier, the far western and far southeastern counties of the
watch are the most sensitive at this point. Should rain fall farther
north or east of the region, the Flash Flood Watch will likely be
able to be cancelled before the Saturday evening expiration.
Otherwise, expect cool temperatures to continue overnight with lows
in the 50s to low 60s and highs in the 70s to near 80 on Saturday.
Saturday night lows are forecast to fall into the mid 50s to mid 60s
and will have to watch for the potential of some patchy fog
development given recent rainfall and some clearing of cloud cover.
LONG TERM (Sunday through Friday)...
Generally dry conditions will linger into Sunday, but the approach of
a closed low from Baja California will allow for low rain chances to
creep back into the Rio Grande Plains by Sunday afternoon. Rain
chances will then spread back across the region from west to east
Monday through Wednesday as this disturbance lifts into North Texas
and shifts east of the state as an open wave. Shortwave ridging will
allow for drier conditions to settle back into the region mid-week.
Rain and cloud cover will keep temperatures below seasonal normals
through the middle of next week with some moderation by late next
work week as ridging builds overhead.
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 57 74 59 78 59 / 60 30 - - 10
Austin Bergstrom Intl Airport 57 74 56 79 58 / 60 40 - - -
New Braunfels Muni Airport 58 77 57 79 59 / 60 30 - 10 10
Burnet Muni Airport 54 72 55 76 57 / 60 30 - 10 10
Del Rio Intl Airport 58 80 62 79 64 / 40 - - 30 30
Georgetown Muni Airport 55 72 54 77 58 / 60 30 - - -
Hondo Muni Airport 59 78 59 81 61 / 60 20 - 20 20
San Marcos Muni Airport 58 75 58 79 58 / 60 40 - 10 10
La Grange - Fayette Regional 62 76 61 80 60 / 60 60 - - -
San Antonio Intl Airport 58 76 60 79 60 / 60 30 - 20 10
Stinson Muni Airport 61 77 61 79 61 / 60 30 - 20 10
Flash Flood Watch through Saturday evening for Atascosa-Bastrop-
Area Forecast Discussion
National Weather Service Paducah KY
927 PM CDT Fri May 10 2019
Issued at 927 PM CDT Fri May 10 2019
Tracking some scattered light showers mainly impacting the
southern Pennyrile region of west KY. Raised PoPs to cover the
scattered nature of this activity but it should be moving out of
the area shortly after midnight. Other activity that we are
watching is now moving northeast out of Arkansas up into parts of
southeast MO. This batch of precipitation will continue moving
northeast and impact parts of SEMO and maybe far west KY late this
evening, but is forecast to slowly dissipate as it moves
northward. We have added PoPs to these areas.
Taking a peek at the 00Z model data that is trickling in, it
appears as though precipitation may be moving in a bit quicker
than originally thought for tomorrow and western parts of the
area will be dealing with morning showers. The midnight shift
will be taking a more comprehensive look at this during the
.SHORT TERM...(Tonight through Sunday night)
Issued at 245 PM CDT Fri May 10 2019
A rather cool and wet Mothers Day weekend is in store for our
region. There are still some significant differences in the model
mass fields, but they do not seem to affect our sensible weather.
Even the model qpf fields have come into fair agreement, despite
differences in the track and strength of the system.
First things first, an area of rain is currently tracking
northward into western Tennessee this afternoon. The hrrr and rap
briefly bring this rain into western Kentucky early this evening
before moving it out. A small pop will be added for west Kentucky
late this aftn and early evening to account for this rain.
The arrival of the main rain shield will be on Saturday morning
for most of our area as another upper level shortwave ejects
northeast from the southern Plains. The models differ on the track
and strength of the associated surface low. It appears the low
will be quite weak, passing northeast across western Tennessee on
Saturday evening. The 850 mb low or trough is forecast to be along
the lower Ohio Valley, which will result in a weak southerly flow
of elevated warmth and instability. Some thunder will be kept in
the forecast for Saturday afternoon and evening in the 850 mb warm
sector. Model qpf guidance has been consistently trending
downward, and it appears most places will receive well under an
There will be a fairly strong temp gradient Saturday. Highs will
be only in the 50s along and west of a kmvn to kcgi corridor,
where rain and north winds will dominate. On the other end of the
spectrum, highs in the khop area should be well up in the 60s,
where rain may not start until mid afternoon and winds will be
Sunday should be a rather cloudy day despite drier northwest
winds on the back side of the departing system. A strong upper
level disturbance in the northern branch of the jet will close off
into a deep low over the upper Mississippi Valley. This low will
move east into the Great Lakes area on Sunday night. Impulses
rotating around the back side of the low will bring small chances
of showers Sunday into Sunday night. Cold air aloft associated
with the upper low could enhance the showers Sunday
.LONG TERM...(Monday through Friday)
Issued at 245 CDT Fri May 10 2019
The medium range guidance is in reasonable agreement for next week
and has been fairly consistent for the last few days now.
The weekend storm system will slowly pull away from the region
Monday, and a few showers may linger into the morning hours. Behind
this system we will be under northwest flow aloft through Thursday,
but ridging will build over the region on Friday, as a large trough
pushes onto the west coast.
The only potential weather-maker through the week will be a clipper
system and possible cold frontal passage Wednesday into Wednesday
night. The medium range models have been pretty consistent with a
frontal passage in this time-frame for a few days, but the strength
of the upper system and push with the front have varied and continue
to vary amongst today`s 12Z guidance.
Moisture return ahead of the cold front will be very limited, but
the GFS eeks out just a bit of surface-based instability Wednesday
afternoon and evening, so a thunderstorm or two will be possible.
The GEM is the strongest with the upper system and has decent flow
aloft, so a strong storm cannot be completely ruled out, if any can
get going. Given the uncertainty in the details, will limit PoPs to
low chance levels and limit the mention in the HWO to locally heavy
downpours and lightning.
Dry surface high pressure will keep the area dry and cool Monday and
Tuesday. Temperatures will start out well below normal on Monday and
slowly climb to near normal levels for the last half of the week.
Issued at 650 PM CDT Fri May 10 2019
As cool low level air undercuts southwesterly flow aloft, surface
winds less than 12 knots will be out of the northeast most of the
next 24 hours. Pesky MVFR cigs may hang over parts of western KY
(especially near the TN state line) this evening with the passage of
a low pressure area through central TN. TAFs will be amended as
appropriate. MVFR cigs will become more likely over the southern
half of the region by daybreak, and over the northern half by
afternoon. Meanwhile, the next impulse in the flow aloft will cause
showers to move in from the west starting around daybreak. While VFR
vsbys in rain are forecast at this time, MVFR vsbys are possible in
heavier pockets of rain, mainly in the afternoon. The probability of
lightning was too low to include in the TAFs at this time.