Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/29/21
Area Forecast Discussion
National Weather Service Corpus Christi TX
721 PM CDT Wed Apr 28 2021
/00Z TAFs/ Gusty SE winds with gusts of 20-30 KTs this evening
gradually weakening around 06Z. MVFR CIGs expected to develop
near the coast over the next few hours, with lowering CIGs toward
COT/LRD toward and after 10Z. Focus switches to the storms moving
out of Mexico. Expecting most activity to remain north of LRD-COT
due to strong capping over the region, but will monitor for any
development farther south that could potentially affect the
western sites. For now, will hold VCSH at COT for this evening.
A front will move south through tonight and bring showers and
possible thunderstorms. Have added at least VCSH for ALI/VCT/CRP
after 06Z as thunder may be a bit more isolated. Rain chances
should begin to taper off through the late afternoon with CIGs
lifting to VFR, with the exception of MVFR CIGs lingering a bit
longer near COT.
.PREV DISCUSSION... /Issued 351 PM CDT Wed Apr 28 2021/
SHORT TERM (Tonight through Thursday Night)...
One final shot for severe storms exists tonight across portions of
La Salle and Webb Counties, although the latest mesoanalysis is
not looking too supportive for this in the coming hours. Even with
strong heating in place across our western counties, a complete
lack of boundary layer cumulus says the cap is still too strong.
This is not the case farther up the Rio Grande where a mesolow is
evident on visible satellite over Maverick County complete with
clusters of agitated cumulus. So the best storm chances should
hold NW of the Brush Country this evening, although the HRRR and a
few other CAMs have suggested a lone cell or two developing in
Webb and Duval Counties this evening with the arrival of an upper
speed max. Interestingly, this speed max is confirmed on satellite
with a recent uptick in cirriform clouds crossing Laredo, yet the
we feel the cap is still too strong at this time for convective
initiation in these areas. This should change later tonight over
the northern Brush Country as the southern fringes of convection
move closer ahead of a Pacific cold front.
Overall, PoPs were trimmed lower tonight through the day tomorrow
as ascent remains shallow along the slow-moving front. Shallow
showers may be the dominant mode along this front, but as this
front temporarily stalls over the Coastal Bend Thursday afternoon
we should see convective temps met at times which would open the
door to some CAPE. Otherwise, the front should finally nudge into
the coastal waters Thursday night ahead of light northerly flow.
Rain chances should expand to beyond the front late in the night
as stronger SW flow overspread the region ahead of a stalled upper
low to our west; however, some residual dry slotting may keep the
column aloft too dry until much stronger ascent arrives early in
the long term forecast.
Lastly, minor coastal flooding is again on tap late tonight/early
Thursday morning during high tide given favorable swell periods,
moderate to strong onshore flow and a recent full moon.
LONG TERM (Friday through Wednesday)...
Latest model runs are a bit more in agreement with an upper level
cut off low developing and meandering west of the area Friday and
Saturday. This will keep rain chances in the forecast into the
weekend. PWATs remain high with around 1.5 inches near the Rio
Grande to around 2 inches along the coast. The deep abundant
moisture will combine with a series of embedded short waves tracking
around the main upper low to generate scattered convection Friday.
Mid level instability and the upper support warrants a mention of
Chances look better by Saturday as a warm front/surface trough works
its way north across the area. Surface based CAPE increases to
moderate values. RRQ of upper level jet is progged to be over the
CWA Sat. These conditions could lead to some strong storms Saturday.
Rain chances decrease from west to east Sunday as the upper low
moves east of the area with dry conditions expected through next
With expected cloud cover and rain chances, weekend high temps will
be cooler. A warming trend will begin Sunday as the warm front lifts
north of the area. Triple digit temps are expected out west by
early next week.
Strong onshore flow this evening will weaken to moderate levels
over the bays and nearshore waters toward midnight, and the open
waters early Thursday morning. A slow-moving cold front will
approach the waters Thursday afternoon before moving into the
waters Thursday night ahead of weak northerly flow. Isolated to
scattered showers and thunderstorms are expected near this front.
Weak to moderate offshore flow will continue Friday, then become
onshore over the weekend. Weak to moderate northeast to east flow
can be expected Friday and Saturday, becoming southeast by
Saturday night. Weak to moderate onshore winds on Sunday will
increase to more moderate levels Sunday night through Monday.
Scattered showers and thunderstorms are possible late in the week
and through the weekend. Drier conditions can be expected early
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 74 87 69 82 63 / 20 20 40 40 50
Victoria 73 83 68 81 63 / 30 30 40 40 40
Laredo 74 94 70 84 64 / 20 10 30 40 50
Alice 73 93 68 84 62 / 20 20 40 50 50
Rockport 73 84 69 81 65 / 20 20 40 40 40
Cotulla 73 92 67 85 63 / 30 20 30 40 50
Kingsville 74 91 69 82 63 / 20 20 40 50 50
Navy Corpus 74 82 70 79 66 / 10 20 40 40 50
TX...Wind Advisory until 7 PM CDT this evening For the following
zones: Bee...Coastal Kleberg...Coastal Nueces...Coastal
Refugio...Coastal San Patricio...Goliad...Inland Calhoun...
Inland Kleberg...Inland Nueces...Inland Refugio...Inland
High Rip Current Risk through Thursday morning For the following
zones: Aransas Islands...Calhoun Islands...Kleberg
Coastal Flood Advisory from 4 AM to 10 AM CDT Thursday For the
following zones: Aransas Islands...Calhoun Islands...
Kleberg Islands...Nueces Islands.
GM...Small Craft Advisory until 7 AM CDT Thursday For the following
zones: Coastal waters from Baffin Bay to Port Aransas out
20 NM...Coastal waters from Port Aransas to Matagorda Ship
Channel out 20 NM...Waters from Baffin Bay to Port Aransas
from 20 to 60 NM...Waters from Port Aransas to Matagorda
Ship Channel from 20 to 60 NM.
Small Craft Advisory until 11 PM CDT this evening For the
following zones: Bays and Waterways from Baffin Bay to Port
Aransas...Bays and Waterways from Port Aransas to Port
Area Forecast Discussion
National Weather Service State College PA
1120 PM EDT Wed Apr 28 2021
A stalled front will remain near the New York border tonight,
then an area of low pressure approaching from the midwest will
lift across northern Pennsylvania on Thursday. An upper level
trough will swing over the region Friday, then high pressure
will build in on Saturday.
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Quasi-stationary front remains draped from Lake Erie into
central NY state late this evening. A ribbon of high pwats
pooling south of this boundary, combined with a weak shortwave
approaching from the lower Grt Lks, will keep the chance of
showers in the forecast overnight, mainly over the northern tier
counties. A few lightning strikes still noted at 03Z across the
northern tier, where some minimal cape on the order of about
500 J/kg persists. RAP cape fields indicate a few lightning
strikes will remain possible up there well into the night, as
there is little room for additional cooling based on current
A developing surface wave over the Mississippi Valley is progged
to track northeast overnight. Strong isentropic lift at nose of
associated low level jet should arrive over the western half of
Pa toward dawn. Thus, have increased POPs toward daybreak over
the western counties.
It will be an unseasonably warm night under mostly cloudy skies south
of the stalled front. Lows are expected to range from the low
to mid 60s in most spots. However, the quasi-stationary front
will likely dip just south of the NY border overnight, resulting
in lows in the upper 50s along the northern tier.
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY/...
Thursday will feature more widespread shower activity, as the
aforementioned sfc wave deepens as it slides ENEWD along
the aforementioned frontal zone draped across NW/Ncentral PA.
Categorical POPs are supported throughout most of central PA.
However, the steadiest rain should fall across the extreme
northwest part of the forecast area, where fgen forcing is
strongest at nose of low level jet. Elsewhere, the rain should
be showery in nature. Latest HREF and operational runs indicate
rainfall of around 1 inch across the northern tier, with only a
tenth of an inch or less across much of the Lower Susq Valley.
Modest instability will exist to the south of the frontal zone
across the southern third of CPA tempered by antecedent
precipitation and/or abundant cloud cover, but deep shear
profiles will still be rather strong. Day2 MRGL outlook has been
suppressed slightly southward to cover the southern third of
the area as a result. The potential exists for an isolated
strong storm Thursday afternoon/evening.
A cold front trailing the sfc low will traverse the area
Thursday night with showers fading into early Friday morning in
cooler post-frontal NW flow. Latest model guidance shows the low
intensifying into New England on Friday. A tightening p-gradient
and reinforcing shortwave/surge of CAA should translate into a
period of strong gusty NW winds. Similar to the evening shift
Tue, the day shift Wed also nudged gusts above the NBM 90th
percentile into the 35-40 mph range approaching advy levels
based on deterministic fcst soundings.
Friday is the last day of April 2021 and it will be noticeably
colder, especially coming off of 2 days of summerlike
conditions. The MaxT24hrChange will be a setback of 10 to 15
degrees colder with highs a few to several degrees below average
ranging from around 50F in the NW to mid 60s SE. A rather
chilly Friday night with lows Saturday morning in the low
30s/40s to kick off the 5th month of the year. No freeze
concerns at this time with 7 more zones activated in the growing
season May 1.
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
High confidence in cool and dry conditions Saturday, as upper
trough lifts out and surface high builds into PA. Dry air at low
levels will likely translate to afternoon minRH values around
30% or lower, although a subsidence inversion should prevent the
mixing down of even drier air above the BL. All medium range
guidance develops an upper ridge off of the east coast Sunday
into early next week, with a quasi-stationary front draped
across the Grt Lks into northern New England. A deep southwest
flow should result in a return to above normal temperatures
during this period, along with an increasing chance of showers,
especially closer to the front over northwest PA.
The latest ECENS and GEFS plumes indicate the best chance of
showers will come in two bouts during the first half of next
week. The first is likely Monday PM in association with a
southern stream shortwave lifting out of the Miss Valley. The
progged surface low track through the eastern Grt Lks favors
northwest Pa for the most significant rain from this system.
The second bout is likely to come Tuesday night or Wednesday
associated with next wave of low pressure riding along quasi-
stationary front. Current guidance suggest this system will
track a bit further south, bringing a decent chance of rain
across all of central Pa.
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
For the 18Z TAFS, made some large changes. Unless things get
active soon, backed off on the timing of the showers later this
afternoon. A lot of cloud cover outside. Took thunder out of
BFD. While there is a storm on the north side of Lake Erie at
the current time, really hard to see much going on in our area
given the time it would get into our area.
BFD would have the best chance of a shower late afternoon, then
perhaps JST later this evening. Thus backed off on lower CIGS
A weak low forecast to form on the cold front and lift northeast
on Thursday. This system would likely in a higher chance of
showers and storms later Thursday, with lower conditions.
Thu...Restrictions possible areawide in showers. Isolated
Fri...Restrictions possible with rain showers. Gusty W/NW winds.
Sat...MVFR cigs BFD/JST possible in morning. Breezy.
Mon...Mainly VFR conditions, but a chance of showers late NW.
Near-record high temperature (87F) at Harrisburg today. The
record high is 90F set in 1957.
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
622 PM CDT Wed Apr 28 2021
.DISCUSSION...(This evening through Wednesday)
Issued at 355 PM CDT Wed Apr 28 2021
Main concerns in the short term are potential for patchy frost
tonight, then low-end near critical fire wx and temperatures Thu and
into the weekend. Focus then turns to next chance for rain Sun
into early next week.
Water vapor shows a positively tilted trough stretching from the
Upper MS Valley all the way into the Desert SW. The upper trough
axis remains close enough to the area that we`re still seeing some
iso shwrs/weak storms this aftn, mainly S of I-80 and E of Hwy
281. Not expecting much from this and what little PoPs we have
will decr thru the eve. Skies are already beginning to clear out
from N to S (a bit faster than expected), and this trend will
continue thru the eve. Brzy N winds will also decr, but probably
won`t go completely calm outside of low valleys and sheltered
areas due to weak reinforcing front set to move in between 06Z and
12Z. Have low temps in the upper 30s from LXN to ODX, so could
see some patchy frost for these areas. If winds end up lighter,
could see slightly lower temps (more frost) given clr skies.
Warming temp trend begins tmrw and continues thru weekend, and
will come with some brzy conditions, at times. Some of the models
suggest RHs could fall to near critical levels Thu and Fri aftn
in the presence of 25 to 30 mph gusts Thu aftn, and 20-25mph Fri
aftn. However, even the typically drier RAP model keeps us above
20 percent (critical) RH levels, so not overly concerned at this
point, esp. considering fuels continue to become less and less
favorable w/ time. Other than the brzy conditions, Thu and Fri
look quite pleasant. Model consensus is for a series of shortwaves
to dig thru the Great Lakes and carve out a deeper upper trough
over the NE CONUS Thu night into Fri AM, but appears this will
remain progressive and too far E to impact our wx. If anything,
flow will take on an incr Wrly, downsloping component compared to
Thu, and with good amnts of sunshine, should see nice jump in
temps to upper 70s to mid 80s for Fri aftn.
Temps jump even more for Sat as lee trough deepens and pulls low
level thermal ridge squarely into the CWA. Incr pressure gradient
force between departing high and new sfc low will lead to brzy and
potentially windy conditions. Forecast high temps are already into
the mid 80s to low 90s, and much like Mon, wouldn`t be surprised
if this is too low and temps trend upward as we get closer. Dry
atmosphere, SW low level flow, and strong insolation argue for
this as well as potentially critical fire wx.
Upper trough that cuts off over TX next 24hrs looks to eject NE
Sun-Sun night, with next cold front entering the CWA Sun aftn-eve.
GFS is more aggressive with QPF along the front relative to the
EC. Like prev forecaster stated, can`t completely rule out some
strong-svr storms along this front, but limited moisture (sfc Tds
generally in the 50s), less than stellar lapse rates, and marginal
shear argue against anything too significant attm. Best rn chances
will be Sun eve into Mon, though official PoPs linger into Tue and
even Wed. This could be overdone, esp if 12Z GFS/EC are onto
anything. Nonetheless, temps will cool off to near normal levels
for Mon-Tue. Temps look to rebound mid to late next week.
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Friday)
Issued at 617 PM CDT Wed Apr 28 2021
Expect a quiet night tonight overall with skies gradually clearing
through the next several hours and early overnight. Cigs may
continue to bound around slightly for the next hour or two between
VFR and MVFR (the main reason being the extent of cloud cover,
BKN vs SCT). Once things begin to clear up VFR conditions are
expected through the end of the period. Also expect winds to quiet
down to light and variable through the overnight. Winds are then
expected to pick up again tomorrow out of the north and northwest
by around mid-day. Gusts are expected to be generally in the
Area Forecast Discussion
National Weather Service Goodland KS
959 PM MDT Wed Apr 28 2021
.SHORT TERM...(This evening through Thursday night)
Issued at 205 PM MDT Wed Apr 28 2021
Satellite imagery and 500 mb RAP analysis showed southwest flow over
the region today, as an upper closed low spun over eastern Arizona
and western New Mexico. An upper trough gradually pushed across the
High Plains, keeping skies cloudy through the day with light
precipitation grazing the northwestern and southeastern zones. At 2
PM MT, temperatures mainly ranged in the 50s. North winds were
observed at 15 to 20 mph, with gusts around 30 mph.
Temperatures fall into the mid 30s to low 40s tonight as northwest
flow develops aloft behind the exiting trough. In the meantime,
skies clear from the northwest and dry weather returns to the
A warming trend begins on Thursday, when a broad ridge amplifies
over the west coast. As a result, temperatures climb into the upper
60s to low 70s and dry conditions continue. North winds gusting up
to 30mph can be expected across much of the area from the late
morning through afternoon hours. Winds taper off and shift towards
the south overnight as temperatures fall into the upper 30s/low 40s
and the ridge noses into the Plains.
.LONG TERM...(Thursday night through Wednesday)
Issued at 244 PM MDT Wed Apr 28 2021
For this long-term forecast package, do expect a return to an active
weather pattern with a variety of weather threats. At this time,
nothing stands out as a more significant threat but that will
need to be resolved for future forecast packages.
Beginning with Friday and Saturday, southwest flow will return
across the region as the upper level ridge begins to break down and
a trough takes shape over the western United States. With the
southwest surface flow, expecting dry weather conditions as well as
a drastic warming trend. With those weather conditions, will need to
think about fire weather threat. The high temperatures should be at
least 10 to 15 degrees above normal, so low relative humidities
seem quite reasonable with warm temps and dry air advection.
Breezy conditions are also possible with a decent pressure
gradient between surface high pressure to the east and developing
low pressure along the Front Range. Thinking elevated to near
critical fire weather conditions are likely on Friday along and
south of I-70, and near critical to critical fire conditions
Saturday from roughly Yuma to Goodland to Oakley.
On Sunday, attention will turn to storm chances once again as
several favorable ingredients for storms come together. First, a
cold front will move south across the High Plains, ending somewhere
across our forecast area during the daytime hours. In addition, a
shortwave trough will move out over the Plains, providing that upper
level trigger mechanism. Finally, warmth will still be in the area
ahead of the front and this time, moisture return from the Gulf
should have arrived to provide instability. Therefore, storms will
be possible, especially along and east of Highway 25. It is still
too early to resolve the details of timing, precise areas, and the
particular severe-weather related threats, but wouldn`t be a
surprise to have a few strong to severe storms at least in the
From Sunday night through Tuesday, active weather will persist in
the form of continuing precipitation chances and cooler weather. Any
severe weather threat should be gone with the front passing
completely through the area by Sunday night. However, still could
have some thunderstorms in the area. With cooler temperatures
forecast, it`s not out of the realm of possibility that a few
snowflakes may be observed somewhere Tuesday morning. However, was
not confident enough in the temperature forecast to mention that in
the forecast package at this time. For now, kept the precipitation
as all liquid but if any flakes were to be observed, keep an eye on
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 957 PM MDT Wed Apr 28 2021
VFR conditions forecast for the TAFs. Light winds tonight will
become gusty close to 18z Thursday. The winds will decline toward
Area Forecast Discussion
National Weather Service Phoenix AZ
527 PM MST Wed Apr 28 2021
Updated Aviation section.
Today will bring some lingering showers and a few thunderstorms
across the high terrain east of Phoenix and considerable warming
to the lower deserts. A strong high pressure system will then
take over late week resulting in much warmer temperatures and
highs likely topping 100 degrees by Saturday. Temperatures will
moderate somewhat early next week, but stay well above normal as
dry conditions and mostly clear skies prevail.
The upper level low continues to slowly shift southeastward through
the region with the low center now just moving into extreme SE NM at
this hour. Showers and a few TS continue to rotate southwestward
around the low center across much of Gila County and into parts of
extreme eastern Maricopa County. Although most places have seen
little or no rainfall (so far), some spots across southern Gila
Counties and extreme eastern Pinal Counties have seen measurable
rainfall, with San Carlos RAWS measuring 0.40 inch between 1214 pm
and 114 pm as a heavier shower moved across the region. Although
drier air will gradually work in from the west through the remainder
of the day/evening, there looks to be enough residual moisture
across eastern Arizona to combine with daytime heating and steep
lapse rates for additional convection. Hi-res models show convection
attempting some westward propagation of the convection through the
rest of the afternoon and into the early evening. However, HREF and
HRRR guidance are still generally keeping the showers and
thunderstorms across Gila County, but still can`t rule out a few
inching into far eastern Maricopa and eastern Pinal Counties. A few
hundred J/kg of CAPE and plenty of 0-6 km bulk shear may support a
brief organized storm capable of small hail and sub-severe gusty
winds across Gila County. A more likely impact to the lower deserts
will be outflow winds from these showers/TS, with gusts as high as
25-30 mph possible. mainly across the far east and NE valley.
Across the lower deserts today, significant warming is still
forecast to occur as the impressive upper level ridge just off the
West Coast nudges eastward into our region. However, the battle
between the strong ridge to our west and the slow exit of the upper
low will continue through the rest of the week. Model ensembles have
continued to trend toward a slower exit of the upper low. This shift
is expected to keep the highest heights from the ridge across
central California northeastward into the Great Basin. Despite this
subtle shift, very warm temperatures are still expected, but the
likelihood of reaching 105 degrees across the Arizona deserts
continues to drop. The latest forecast now calls for highs likely
just topping 100 degrees across the western deserts on Friday with
the Phoenix area into the upper 90s. Saturday still looks to be the
hottest day with median NBM temperatures of 101-104 degrees across
the western deserts to 99-102 for the Phoenix area. Daily record
highs will still in jeopardy though, particularly Saturday with
Phoenix`s probability of tying Saturday`s record of 103 now down to
28%, Yuma (106) at 10%, and El Centro (106) 26%.
The hot temperatures Friday and into the weekend will begin to
back off starting Sunday as an incoming trough into the
Northwestern U.S. quickly dives southeastward into the Great Basin
by Sunday afternoon. This will suppress heights aloft over our
region, likely dropping highs back into the upper 90s for Sunday.
Further cooling should be realized into early next week with
Monday`s highs potentially into the lower 90s, or closer to
normal readings. Eventually, the trough is likely to shift to the
east with either zonal flow or slight ridging taking over across
the Desert Southwest by the middle of next week. As a result, NBM
guidance points toward warming temperatures again starting next
Tuesday with more potential for 100 degree days at some point
during the latter half of next week.
.AVIATION...Updated at 0027Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
A broad swath of easterly outflow winds (driven by evaporative
cooling from weak showers originating over higher terrain) has
exited the metro area. Significantly lighter easterly winds (gusts
15-25kts) will continue to weaken this evening but east and
southeasterly directions are expected to continue the rest of the
evening and overnight. One caveat is that there may be a period
until about 03Z with variable directions as westerly winds in the
lower levels above the surface mix with the remnants of the
outflow. Virga showers will continue to dissipate as well with
clear skies developing later this evening. Before then, SCT-BKN
layers around FL100 can be expected with BKN layers roughly around
The upper low that caused the shower activity and associated
surface winds is centered near the New Mexico Bootheel and will
sag southeastward tonight and Thursday. The strong northerly flow
aloft (roughly AOA FL100) will trend to northeasterly. Winds below
that level (but above the surface) will trend from westerly this
evening to northerly overnight then easterly during the day
Southeast California/Southwest Arizona including KIPL and KBLH:
An upper low centered near the New Mexico Bootheel is driving
moderate to strong north and northeasterly flow at the surface and
aloft. The low will sag southeastward tonight and Thursday.
Northeasterly winds above the surface will continue tonight and
through the day Thursday. Northerly breeziness at the surface will
weaken this evening with light westerly directions developing at
KIPL (favoring northerly at KBLH). Northerly surface winds will
redevelop by late morning at KIPL. Northerly surface winds at KBLH
will trend toward northeasterly Thursday afternoon. But, speeds
Thursday will not be as strong as they were today. Otherwise,
skies will be clear.
Saturday through Wednesday:
Strong high pressure will affect the region early in the period
with near record heat likely for the upcoming weekend. High
temperatures will climb each day through Saturday with 100-105
degrees possible before cooling slightly starting Sunday. A weather
disturbance passing well to the north will bring even cooler temps
for the early and middle part of next week, with lower desert highs
falling into the low-mid 90`s by next Wednesday. Seasonably dry
conditions are expected through the period with min RH values mostly
in the mid single digit-low teen range. Winds will follow diurnal
trends, but with somewhat elevated winds/fire danger levels on
.Daily Record Highs...
Phoenix Yuma El Centro
.......... .......... .........
Fri 4/30 102 (1943) 103 (1943) 104 (1965)
Sat 5/1 103 (1985) 106 (1947) 106 (1947)
Sun 5/2 107 (1947) 111 (1947) 113 (1947)
.SPOTTER INFORMATION STATEMENT...
Spotters should follow standard reporting procedures.
Area Forecast Discussion
National Weather Service Shreveport LA
1021 PM CDT Wed Apr 28 2021
The latest runs of the HRRR as well as the CAMs and 00Z NAm
suggest that a line of more robust convection is expected to
develop by/after 06Z Thursday over portions of extreme NE TX/SE
OK/SW AR, near and ahead of a weak cold front that will advance SE
into these areas, coinciding with a subtle upper level impulse
ejecting NE in the SW flow. This is a little farther SE than what
has been depicted over the last couple of days, with the 40-50kt
Srly LLJ enhancing mid level convergence once the upper divergence
increases late ahead of the closed low sags SSE into Nrn old MX
from Srn NM. These progs suggest that QPF`s of 2-4 inches are
possible, with isolated higher amounts of 5-6+ inches depicted by
the HRRR and CAMs over portions of extreme NE TX (from Red River
and Northwest Bowie Counties) into portions of extreme SW AR.
Given PW`s in excess of 1.8 inches (on the higher end of
climatology), and the extent of forcing late, have expanded the
Flash Flood Watch to include Bowie, Little River, Sevier, and
Howard Counties, while also extending the duration of the Watch
through 21Z as the convection and potential flooding may extend a
little later into the afternoon over these areas. Any svr threat
looks as if it will wait until after midnight when the deeper
convective line develops, although it will encounter weakening
CAPE as it moves into the region.
Otherwise, did make some minor adjustments to pops, mainly to trim
back the Srn extent over E TX/NW LA/SCntrl AR, while also raising
min temps a bit over Lower E TX/N LA which should remain rain-
free, and be influenced with the low clouds/wind, thus resulting
in warmer readings.
Zone update already out...grids will be available shortly.
.PREV DISCUSSION... /issued 811 PM CDT Wed Apr 28 2021/
Zone update just sent for the issuance of TOR Watch #121 in effect
until 07Z Thursday for a small portion of extreme NE TX/SE
OK/adjacent sections of SW AR. A gradual uptick in convection has
been observed over the last hour over portions of NE TX/SE OK,
with the latest HRRR as well as the global models suggesting
convection deepening late this evening ahead of a weak cold front
over Cntrl/NE OK, which will slide SE thus resulting in the
convection slowly building SE into these areas late.
Did add severe and heavy rainfall mention for these areas, which
coincides with the Flash Flood Watch already in effect.
PREV DISCUSSION... /issued 648 PM CDT Wed Apr 28 2021/
VFR conditions will continue for much of this evening, although
MVFR cigs are expected to develop after 02-04Z across portions of
E TX/N LA, and spread N across the remainder of the region after
06Z Thursday. Meanwhile, convection is expected to increase later
this evening across portions of extreme NE TX/SE OK and adjacent
sections of Wrn AR, before gradually sliding SE overnight. This
convection may come as close as the TYR/TXK terminals by 08-10Z,
where VCTS was maintained, although tempo thunder mention may be
needed in later TAFs with reductions to cigs/vsbys. This
convection should persist over these same areas through much of
the morning, before weakening by mid to late morning. However,
additional redevelopment is expected through Thursday afternoon
near and ahead of a weak cold front that will drift SSE into
extreme NE TX/SW AR. While this convection will likely maintain
MVFR cigs through much of the day, the lower cigs should
eventually lift/become VFR by late morning/midday elsewhere across
Lower E TX/N LA, although some reductions to cigs/vsbys are
possible in the afternoon in and near the redeveloping convection
along the front. SSE winds 8-13kts tonight through much of
Thursday will eventually become N 5-9kts with the fropa over SW
AR/E TX and NW LA along/N of I-20. /15/
.PRELIMINARY POINT TEMPS/POPS...
SHV 72 84 64 77 / 20 60 60 40
MLU 70 86 65 75 / 0 40 70 40
DEQ 68 77 59 77 / 90 90 40 20
TXK 71 78 62 75 / 60 80 60 30
ELD 69 81 61 75 / 20 60 60 30
TYR 70 79 64 75 / 60 80 60 30
GGG 70 80 64 75 / 40 70 70 40
LFK 71 85 68 76 / 10 60 50 40
AR...Flash Flood Watch through Thursday afternoon for ARZ050-051-059.
OK...Flash Flood Watch through Thursday afternoon for OKZ077.
TX...Flash Flood Watch through Thursday afternoon for TXZ096-097-108-