Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/02/21
Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
625 PM CDT Fri Oct 1 2021
.DISCUSSION...Updated for latest aviation discussion below.
.AVIATION...MVFR to IFR conditions persist where heavy
thunderstorms continue across the lower RGV. Most convective
activity is expected to taper off this evening, returning ceilings
to VFR. The chance of rain continues on Saturday, with little
confidence in timing at this time.
.PREV DISCUSSION... /issued 303 PM CDT Fri Oct 1 2021/
SHORT TERM (Tonight through Saturday Night): The biggest question in
the immediate short term is how far south a subtle surface/old
outflow boundary will make it. As of 2:45 PM, it was located in
southern Starr, southern Hidalgo and northern Cameron Counties and
continues to inch south. There`s also a coastal trough producing
locally heavy rain along the coast These two entities will the focal
points for more showers and storms through much of the evening. The
boundary will eventually stall near the Rio Grande River tonight,
but the question is where exactly does it stall. The start of the
short term forecast is leaning quite a bit on the HRRR as it has
handled the ongoing convection the best; it suggests the boundary
makes it into Mexico by 00-01Z and see no real reason to deviate
from that too much. With an additional 1 to 3 inches of rain
possible through this evening, we will maintain the Flash Flood
Watch for our Coastal Counties and Hidalgo, Jim Hogg, and Brooks
Counties. As the boundary sags south, a strong southerly flow in the
low levels will help create some overrunning showers tonight, so
POPs remain somewhat elevated along the Middle and Lower Rio Grande
and immediate coast through tonight.
The closed H5 low in NM will shift into the Central Plains Saturday
and allow for some ridging to build across southern Texas. This
ridging is represented by the globals showing a touch of drier air
between 850 & 700 mb, so have lowered POPs a touch Saturday
afternoon. However, with PWATs still forecast to be between 1.8 to
2.2", any showers or storms that do develop could produce quite a
bit of rain.
Temperatures tonight will run in the middle to upper 70s. Have
bumped up highs a touch Saturday due to a slightly drier forecast,
but we`ll still hover around 90 for the eastern half of the CWA and
the lower to middle 90s out west. Another mild and humid night is in
store Saturday with lows in the lower to middle 70s.
LONG TERM (Sunday through Friday): Starting with the
synoptic set up, at the 200mb level, a jet streak located over
central Texas partnered with a mid-level positively tilted trough
over the upper Midwest, provides an unstable environment for our
CWA. This will allow for showers and thunderstorms to continue into
Sunday. As the jet moves northward, a weak cold front from the
trough over the upper Midwest moves into Deep South Texas for
Monday. GFS/ECMWF show a chance for showers and thunderstorms ahead
of the cold front as it moves through by 12z Monday. The front is
expected to exit the area by Monday evening and be replaced by a
ridge building in the western CONUS bringing us much drier
As for high temperatures, due to an abundance of cloud cover and the
arrival of the weak cold front, they will remain slightly below
normal. Low temperatures will remain normal until the front moves
through Monday night and then will be below average through the
period. Dew points start to really take a dive by Tuesday night with
values in the 50-60s. The effects of the front diminish by Friday as
temperatures and dewpoints return to their seasonal averages. As for
the winds, they are expected to turn northerly with the arrival of
the front. They will stay northerly during the daytime hours then
shift to the east overnight. That wind pattern will prevail until
Friday when the winds turn southeasterly again.
MARINE (Tonight through Saturday Night): Ongoing showers and storms in
coastal waters will remain in the forecast through this evening. Any
showers and storms could produce locally enhanced winds and waves.
Outside of the rain and storms, winds have been between 10 to 15
knots with seas near 4 feet, so no SCEC or SCA conditions are in the
forecast tonight. As the pressure gradient further weakens tonight
into Saturday it will allow for a lower southeasterly winds
Sunday through Friday: Moderate onshore flow will prevail along
the lower Texas coast through the period due to convection over
the coastal waters. Winds turn northerly/easterly due to the
incoming front by Monday afternoon and eventually turn back
southeasterly by Friday. Seas will be at 2 to 3 feet through
Wednesday when they drop off to 1 to 2 feet.
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 77 88 77 87 / 60 40 30 40
BROWNSVILLE 77 90 78 89 / 60 40 40 40
HARLINGEN 75 90 75 88 / 50 40 30 30
MCALLEN 76 90 76 88 / 50 40 30 30
RIO GRANDE CITY 74 93 75 91 / 40 40 40 20
SOUTH PADRE ISLAND 80 85 80 83 / 50 40 40 50
TX...Flash Flood Watch until 10 PM CDT this evening for TXZ249>251-
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AREA FORECAST DISCUSSION
National Weather Service Hastings NE
629 PM CDT Fri Oct 1 2021
.DISCUSSION...(This evening through Friday)
Issued at 345 PM CDT Fri Oct 1 2021
Main forecast concern is potential for shwrs/storms through Sat
evening, as well as temperatures and cloud cover.
Quiet conditions this evening before another round of showers, and
possibly a few thunderstorms, TRIES to move in later on tonight.
However, trends for decreasing PoPs continues for areas N of the
KS/NE state line. KS counties will probably have some activity to
dodge, esp. Sat AM, but QPF amounts have also trended downward.
Once this wave departs Sat eve, dry conditions and beautiful fall
weather will dominate the rest of the forecast with plentiful
sunshine, highs in the 70s-low 80s, and lows largely in the 40s
expected EVERY DAY next week!
Today has been a tale of two halves, with SW third breaking out
into sunshine and experiencing pleasant temps in the 70s, whereas
the NE 2/3rds have been socked in low clouds all day, and as a
result, is around 10 deg cooler. We`ve remained on the dry side
today, and not expecting much through the eve, other than perhaps
a few sprinkles over the far N/NE.
The upper wave near the Four Corners will gradually eject NE
later tonight and into Sat, but model trends from the past 24 hrs
of decr PoPs/QPF has continued. Models have also trended a bit
slower with the onset, so I think most, if not all, areas will
remain dry through midnight. The N edges of an arcing band of
scat/bkn shwrs should edge into KS zones 06-09Z tonight, then try
to expand into far S Neb. zones toward dawn. However, it appears
the main upper energy will track far enough S, then E, of the area
to spare the Tri Cities and areas N and W from much of this
activity. Thus, have capped PoPs at 20 percent NW of a line from
Arapahoe to Aurora, with max PoPs around 60 percent over S
portions of our KS counties. Quite frankly, though, this may still
be too high as 18Z HRRR keeps primary shield closer to I-70.
Ultimately, the greatest impact for majority of CWA may actually
come from pop- up shwrs during the "heating of the day" as a
pocket of cooler mid- level temps and higher low level RH swing
through. The specifics regarding cloud cover remain a bit
uncertain, though, and will play a role in any potential pop-up
shwr coverage. Some models bring in a good amount of clearing, esp
W/SW, while others keep us in low clds all day. Think clds will be
most pervasive N and E portions of CWA, so decr highs a couple
deg. It will def feel fall-like in the AM with temps in 50s/60s
under cldy skies and NW breeze. Aftn highs will probably range
from mid 60s NE to low (maybe mid) 70s SW. All PoPs should end by
03Z Sat. One other note regarding fog potential...can`t rule out
some areas of fog late tonight, mainly over W few counties, but
confidence is low owing to incr mid to high clds. Think best
potential for (potentially dense) fog will be off to the W/NW.
The rest of the forecast is incredibly quiet and pleasant for
early Oct. The entire forecast from Sun thru next work week
remains dry, and ensembles aren`t showing even low chcs until
next weekend sometime. Not only is the forecast dry, but temps are
expected to be very nice in the 70s to low 80s each day. Usually
when we get dry/mild patterns like this in Oct we have to monitor
potential for at least SOME fire and/or frost concerns...but
honestly even these concerns appear marginal, at best. Sun AM
appears to be the coolest morning behind the departing wave in
environment of clearing skies and lgt winds. Went on the colder
side of guidance (10-25% NBM and CONSMOS), and this brings areas
like ODX and LXN towards 39-41F, but rest of CWA should remain
several deg warmer. None of the aftns look particularly concerning
for fire wx.
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Sunday)
Issued at 623 PM CDT Fri Oct 1 2021
Rather difficult forecast this evening and confidence isn`t the
highest. MVFR cigs are expected to continue at the terminals for
the next couple of hours before models show some scattering and
lifting in the cloud cover. This will likely only last a few hours
(though confidence in this break happening at all isn`t the
highest) before cloud cover fills back in. While MVFR cigs are
forecast, the occasional lowering to IFR cannot be ruled out
(though it appears a lot less likely).
Clouds will lift to VFR around tomorrow afternoon and should also
begin to scatter out more over the evening.
Area Forecast Discussion
National Weather Service North Platte NE
626 PM CDT Fri Oct 1 2021
.SHORT TERM...(This evening through Saturday night)
Issued at 357 PM CDT Fri Oct 1 2021
The main forecast challenges through the weekend include
precipitation chances and temperatures. An upper level low pressure
skirts the area tomorrow, bringing a slight chance of moisture to
southern and central Nebraska. Meanwhile, highs slowly rebound from
this taste of fall, but lows dip toward frost and freeze territory
This evening and tonight... The surface low currently (as of 20z)
over KFSD lifts into Minnesota while an attendant H5-7 shortwave
crosses eastern Neb. This pesky low has provided light rain,
drizzle, and fog to north central Neb virtually all day. Meanwhile,
the western half of the state will experience broad upslope flow and
weak moisture advection in the lower levels ahead of the next
system. At least partial cloud cover should be retained, but
northwest Neb may clear out most of the way as forcing is weaker
there. With little to no temperature advection underway and weak
winds in place, this setup could result in quite the gradient in
overnight lows. The current forecast sided with cooler guidance in
the west (lower/mid 40s) to account for potential clearing and
generally middle of the road or warmer end in the east (lower 50s)
where persistent cloud cover is expected.
Saturday... The main upper low over the Four Corners makes it to
Kansas, then gets absorbed into the northern stream. A couple
impulses on the northern edge with increased frontogenesis at H5-7
brush the southern and eastern reaches of the CWA. While light
precipitation is possible, the overall profile does not appear
conducive to a widespread moisture maker. Capped PoP to schc and
limited to basically south of I-80 and east of Hwy 183, where
isentropic upglide coexists with better moisture below H7. Used a
blend of HRRR and HREF for general coverage and timing of the rain
showers. Across the Sandhills and into the panhandle, dry air
entrainment behind the low drives dew points into the lower 40s and
even upper 30s. Forecast soundings suggest rapid drying aloft as
well and subsidence increasing through the day. Max temps should
range from near 70F in the east to mid 70s in the panhandle, right
on target for this time of year.
Sat. night... A broad surface high over the Rockies gains influence
on western Nebraska, reinforcing dry air and light winds. Temp
advection at H85 continues to be weak at best with values generally
around 13-14C. In short, conditions will be ripe for efficient
boundary layer decoupling and maximum cooling. Used some of the
coolest guidance available for min temps, resulting in lower/mid 30s
far west to mid 40s far north central. Confidence is increasing in
frost for northwest Neb, and possibly localized freeze.
.LONG TERM...(Sunday through Friday)
Issued at 357 PM CDT Fri Oct 1 2021
A separate closed low dives south to start the week, essentially
following the Mississippi River, then gets hung up over the
Tennessee Valley. As of now, the greatest forcing and moisture
convergence should lie well east of the forecast area, especially
with an upper ridge building over the southern Rockies. The upper
ridge along with a weak low level thermal ridge will encourage a
continual rise in temps into mid week, along with limited precip
potential. Highs will top 80F once again in the southwest on Monday
and mid/upper 70s elsewhere.
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 626 PM CDT Fri Oct 1 2021
A shield of lower clouds with MVFR ceilings, will meander along
and east of a line from KLBF to KVTN through mid morning Saturday.
This shield of cloud cover, will try to push just to the west of
KLBF and KVTN late tonight resulting in MVFR ceilings at both
terminals. There will also be a small threat for patchy fog,
particularly at the KLBF terminal where visbys could reach 1SM
toward daybreak Saturday. Clouds will then scatter late Saturday
morning with partly cloudy skies and VFR ceilings expected
Area Forecast Discussion...CORRECTED
National Weather Service Lake Charles LA
926 PM CDT Fri Oct 1 2021
Showers are still present over parts of the area. Most of these
showers and will dissipate and move out over the next several
hours but additional showers and thunderstorms could develop
overnight, primarily for southwestern areas.
PoPs were adjusted to account for current radar activity and the
latest run of the HRRR (00Z) indicating modest activity
overnight. Patchy fog will be possible during the late night and
morning hours as winds will be light.
.PREV DISCUSSION... /issued 658 PM CDT Fri Oct 1 2021/
For the 10/02/21 0000 UTC TAF package.
Broad patches of light rain in a swath roughly along the Sabine
River resulting in a slight VSBY restriction at KLCH, which is
expected to improve over the next couple of hours as the rain
gradually comes to an end. Elsewhere, some isolated showers east
of KLFT and KARA are expected to remain east of the terminals,
with another band of showers lifting toward the NW in the
direction of KAEX. This latter feature prompted the insertion of a
brief mid evening TEMPO group at KAEX, with a best estimate of
0230Z for an arrival time assuming it can last that long.
Otherwise, no real concerns in the short term, with VFR expected
to generally prevail the rest of the evening. Heading into the
overnight period, low stratus and VSBY reductions are expected to
develop once again, and have used a blend of latest guidance and
persistence to construct the forecast, with a period of IFR
expected at each site. These conditions will improve generally in
the mid to late morning time period. Latest CAM guidance again
showing the most persistent convective activity focused around
KBPT and KLCH through the day, and more scattered in nature across
the rest of the area.
PREV DISCUSSION... /issued 348 PM CDT Fri Oct 1 2021/
SHORT TERM [Tonight through Sunday]...
Storms over southeast Texas continue a slow march to the east
this evening with some storms now into southwest Louisiana.
Southern Louisiana has seen some storm activity through the day
around New Iberia and Lake Charles. As a result temperatures have
remained on the cool side and this pattern will continue for the
next several days. For tonight looking at areas of fog developing
lowering the vsby late tonight and thru sunrise.
An upper level low continues it`s slow progression out of the
desert sw and looks to been into western Oklahoma and southwestern
Kansas by Sunday morning. A cool front near DFW/FTW remains
nearly stalled but will show some movement as the upper level
system pushes east with the cool boundary expected to approach SHV
Sunday morning. But the main push will be to the north and this
front will be slow to continue it`s movement towards the region
but it will continue. It looks to be a wet weekend but there will
be breaks from the rains... temperatures will also moderate. Front
comes through late Sunday into Monday.
LONG TERM [Monday through Friday]...
At the start of the forecast period, cooler and drier air will be
pushing into the area thanks to a cold front passage overnight.
Throughout the day Monday, rain chances will be rapidly decreasing
from northwest to southeast with the passage of an upper level trof.
Rain chances from this point to the end of the period will be low as
a cutoff low looks to set up over the southeastern US, further
reinforcing dry air throughout the area.
Temperatures do not look to cool down very much for the work week.
Daytime highs will be in the mid 80s and nighttime lows in the low
to mid 60s. With the dry air in place over the region, relative
humidity values will remain fairly low throughout the daily cycle,
making the outdoors feel much more comfortable than they have
in recent days.
.PRELIMINARY POINT TEMPS/POPS...
AEX 71 85 70 85 / 50 70 30 70
LCH 72 84 71 84 / 70 80 40 80
LFT 73 85 72 85 / 40 80 30 80
BPT 71 83 70 85 / 70 80 40 70