Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 01/10/23
Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
545 PM CST Mon Jan 9 2023
...New AVIATION...
.SHORT TERM...
(Tonight through Tuesday night)
Issued at 220 PM CST Mon Jan 9 2023
An isolated shower or thunderstorm remains possible this afternoon
as a warm front creeps north. Fog is a concern later tonight as
warmer than normal temperatures stick around.
A warm front is crawling north through the region as denoted by the
temperature and dew point gradient between the Rio Grande Valley
(temps in the 70s and dew points in the 60s) and the Brush Country
(temps in the 60s and dew points in the 50s). The warm front will
continue to lift north the rest of the afternoon and clear the
county warning area (CWA) this evening. Meanwhile, an H5 shortwave
is moving through northern Mexico and right over the CWA over the
next few hours. While the KBRO radar is showing rain across the
Brush Country and Rio Grande Plains. However, a quick check of the
KCRP radar, which is a bit closer for our friends in the Brush
Country, isn`t as impressive and is quite a bit drier when compared
to KBRO in Jim Hogg and Brooks Counties. Add in an ACARS from KMFE
showing pretty dry mid-levels and most of what is falling out west
is likely virga, or rain aloft evaporating before reaching the
ground. Still, the combination of the warm front plus shortwave and
warmer temperatures could lead to an isolated shower or thunderstorm
this afternoon and evening, but those chances remain less than 20
percent.
Fog then becomes a bigger concern tonight with the potential for a
clearing sky and calming wind. Both the SREF and HREF indicate the
potential for dense fog, but have held off on issuing a Dense Fog
Advisory at this time for one primary reason: cloud cover. As the
shortwave moves overhead this evening, mid to high level cloud cover
is expected to stick around. This would limit the cooling necessary
to get temperatures near the dew point, which is needed for the
formation fog. Still, we`ll mention the potential for locally dense
fog and a Dense Fog Advisory may be issued by later shifts depending
on trends.
Above normal temperatures will continue with lower to middle 60s
tonight, widespread 80s Tuesday afternoon and another night in the
60s Tuesday night. As of now, fog isn`t as big of a concern Tuesday
night due to southerly winds increasing ahead of a developing storm
system and associated cold front across the middle of the country.
&&
.LONG TERM...
(Wednesday through next Monday)
Issued at 220 PM CST Mon Jan 9 2023
Low pressure develops again into the Plains on Wednesday,
strengthening the pressure gradient along the lower Texas coast,
and increasing southeasterly winds. A generally dry front rolls
through Thursday afternoon, followed by strong high pressure
building through the weekend. As with the last couple of fronts,
the best chance, which is not very much, of rain remains offshore
ahead of and with fropa Thursday afternoon, most locations will
remain dry.
Expect breezy conditions Wednesday afternoon and again behind the
front Thursday afternoon, mainly near the coast. Highs and lows
remain above normal through Thursday, drop a few degrees below
normal for Friday and Saturday, and return to above normal Sunday
and Monday. The coldest mornings will be Friday and Saturday, with
clear skies and light winds allowing efficient radiational
cooling to drag obs into the low 40s north and mid to upper 40s
south. A couple of cooler spots, like Zapata and Armstrong, may
even find the upper 30s Saturday morning. Breezy to windy
conditions return Sunday, with Wind Advisories potentially needed,
and another breezy afternoon expected on Monday.
A Fire Danger Statement may be needed Thursday with dry air
behind the front and breezy 20 foot wind speeds, given the surplus
of freeze cured fuels and worsening drought conditions already in
place. Fire weather may also need to be monitored Sunday with
stronger winds expected.
&&
.AVIATION...
(00Z TAFS)
Issued at 528 PM CST Mon Jan 9 2023
MVFR/IFR ceilings forecast for tonight as patchy to dense fog is
expected to move in a few hours after sunset. A Dense Fog Advisory
may be needed later this evening. Conditions improve by late
morning when fog is expected to lift. VFR forecast for tomorrow
with light southeasterly winds.
&&
.MARINE...
Issued at 220 PM CST Mon Jan 9 2023
Now through Tuesday Night...The pressure gradient has all but
collapsed along the Lower Texas Coast with all stations and buoys
reporting winds of less than 10 knots and seas between 2 to 3 feet.
Very favorable marine conditions will continue through Tuesday
afternoon before southerly winds increase later Tuesday night.
Patchy to areas of fog have formed along the immediate coast with
visibilities lowest along the immediate coast and near the beaches.
A slight chance for a shower or thunderstorm remains in the forecast
through the evening as a weak warm front crawls north.
Wednesday through Monday...Breezy southeasterly flow is expected
Wednesday as low pressure develops in the Plains. A cold front
arrives Thursday afternoon with breezy northerly winds continuing
into Friday. Light onshore flow returns Saturday with increasing
southerly winds on Sunday and Monday once again. Small Craft
Caution to Small Craft Advisory conditions are expected Wednesday
afternoon into Wednesday night. Small Craft Advisories are likely
with the front Thursday afternoon through Friday afternoon.
Additional Small Craft Advisories may be needed Sunday afternoon
and Monday afternoon, with a few gale force wind gusts possible on
Sunday. The best chance of rain remains ahead of and with the
frontal passage Thursday afternoon, generally offshore.
&&
.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE 62 80 65 84 / 10 0 0 0
HARLINGEN 61 82 63 85 / 10 0 0 0
MCALLEN 61 83 65 88 / 0 0 0 0
RIO GRANDE CITY 59 85 62 88 / 0 0 0 0
SOUTH PADRE ISLAND 62 72 65 74 / 10 0 0 0
BAYVIEW/PORT ISABEL 61 78 64 78 / 10 0 0 0
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
SHORT TERM...58-Reese
LONG TERM....56-Hallman
AVIATION...65-Soria
Area Forecast Discussion
National Weather Service North Platte NE
528 PM CST Mon Jan 9 2023
...Aviation discussion...
.SYNOPSIS...
Issued at 346 PM CST Mon Jan 9 2023
- Watching Wednesday for potential light snow/wintry mix leading to
some travel impacts through the day.
- Temperatures expected to remain near to above normal values
through much of the forecast period.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 346 PM CST Mon Jan 9 2023
Fairly quiet weather continues through the early portion of the
forecast period. Upper-level pattern remains fairly zonal across
much of the central CONUS. For Monday, we`ve seen temperatures
exceed forecast values fairly easily and this is likely due to
widespread sunshine and h85 temperatures nearing seasonal norms but
increasing WAA and downsloping flow. For tonight...expect a modest
LLJ to overspread portions of the area. Various NWP guidance hints
at some valley fog, mainly for the Platte River system and south
into southwest Nebraska. Given isolated nature even with more
aggressive solutions and low SREF probabilities, will keep mention
out for now but need to monitor threat through this evening.
Expecting lows tonight in the teens to low 20s.
For Tuesday, a weak shortwave will skirt the area to the north during
the daytime. This will initially bring increasing cloud cover
through the early part of the day before a surface trough tracks
west to east and settles around central Nebraska by mid-afternoon.
Increasing flow off the surface thanks in part to the formation of
an h85 low across South Dakota will lead to increasingly blustery
winds for the afternoon, particularly for the Sandhills and points
north. Did boost winds to 15 to 20 mph sustained and gusts closer to
25 to potentially 30 mph out of the west. These breezy conditions
will be short lived as the pressure gradient relaxes with the
shortwave and associated PV anomaly quick to depart to the east by
early Tuesday evening. Lows Tuesday overnight into Wednesday will be
a touch warmer than the night previous with widespread low 20s
expected outside a few locations that may manage to fall into the
upper teens.
.LONG TERM...(Wednesday through Monday)
Issued at 346 PM CST Mon Jan 9 2023
Attention turns towards the next potential for light wintry
precipitation beginning early Wednesday across much of western and
southwest Nebraska. Upper-level flow will gradually back to the
southwest ahead of the next upper-level trough moving onshore the
West Coast. NWP guidance is in fairly decent agreement in placing
the main h5 trough and associated height falls to the south of the
local area. Greatest upper-level dynamics (divergence aloft, PV
advection, etc.) looks to remain south of the forecast area,
however, modest fgen will traverse the area north to south with
increasing strength with southward progression. Did boost QPF in-
line with southern neighbors given hints at some enhanced lift
within a small area of negative EPV. EPS/GEFS show fairly high
certainty of seeing > 0.01" QPF within the 24 hour period ending
early Thursday morning, but probabilities drop off considerably for
higher amounts (specifically 0.1" or greater). Latest trends from
the operational NAM have been to decrease amounts for the I-80
corridor and this is a trend that has continued over the past three
runs (06z, 12z, and 18z). Latest NBM 4.1 guidance shows 50th
percentile values maxing out around 0.15" QPF for far southwest
Nebraska with generally 0.05" or less expected outside of
Perkins/Chase/Hayes Counties. More aggressive solutions depict more
concerning QPF for the I-80 corridor so will need to monitor this
potential closely going forward. For now, have one inch or less of
total snow for most locations and a couple pockets of closer to one
inch with one near and southeast of the Pine Ridge and the other
generally south of Highway 23. Regarding ptype, cannot rule out some
light ice in the morning before increasing moisture aloft increases
cloud ice and leads to a transition to all snow during the daytime.
For now, expecting Dry air will fill the column quickly as the
evening progresses, leading to a swift north to south end to
precipitation late in the day. As for temperatures, will expect a
modest cooldown across the area with highs being pushed down into
the 30s for most locations. Some locations may remain at or below
the freezing mark through the day but not expecting a significantly
cold day.
For Thursday and beyond...highly amplified flow will work into the
area for Thursday behind longwave troughing across the eastern
CONUS. Surface high pressure will dive south into the northern
Plains during the day with cold air expected to graze our
northeastern zones. This should lead to fairly cold daytime
temperatures both Thursday and Friday for these areas with forecast
highs in the upper 20s and low 30s respectively. Elsewhere, with
near seasonable h85 temperatures and general west-northwesterly low-
level flow, temperatures elsewhere should remain above normal for
the time of year. Increasing ridging aloft will arrive in time for
the weekend. This will prolong the drier weather with temperatures
likely to return to above normal values. Even conservative values,
the 25th percentile of NBM guidance, suggests upper 30s to low 40s
which would be 3-6 degrees above normal. So the going forecast plays
towards the warmer side of the forecast envelope which puts
widespread mid to upper 40s for the Sandhills into central Nebraska
with a select few in the far northeast holding closer to 40. Ridge
breakdown looks to arrive towards the latter half of the weekend as
the next upper-level trough moves in from the west. Large
discrepancies in mid-level pattern and placement/timing of
shortwaves casts some doubt in higher confidence but know that low-
end precipitation chances will return to the early part of next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 528 PM CST Mon Jan 9 2023
Biggest challenge this TAF period will be potential for fog
overnight.
Due to lingering snow pack and rapid cooling after sunset the past
few nights have featured some fog development, primarily in the
valleys. Believe this may be the case again tonight as cooling
from below overcomes advancing mid clouds. However in this
scenario the fog will be quite shallow and likely limited to
valleys again. Expect KVTN will remain VFR but fog may waft over
the airfield at KLBF from time to time. To avoid an excessively
long TAF at KLBF when confidence is not high, will introduce a
prevailing OBVIS a few hours after dark and use a tempo to
IFR/LIFR when fog will be most likely. Will amend as needed based
on trends in observations.
Otherwise, expect VFR conditions with increasing mid/high clouds
across central and western Nebraska tonight, and lingering into
tomorrow.
Surface winds will generally be light with little impact to
aircraft operations. Winds aloft will increase a bit but generally
slide by to our east. Another surge in winds aloft will occur
toward the end of the valid period across northern Nebraska but
confidence in timing and location precludes a mention of low level
wind shear at KVTN at this time.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...NMJ
SHORT TERM...NMJ
LONG TERM...NMJ
AVIATION...MBS