Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 04/16/23
Area Forecast Discussion
National Weather Service Fort Worth TX
440 PM CDT Sat Apr 15 2023
...New Aviation, Short Term...
.SHORT TERM... /NEW/
Update:
A cold front continues to move quickly through the region late
this afternoon. The storms currently along the front across the
southeast zones will exit the CWA by 6 PM. Dry, cool, and breezy
weather will prevail behind the front followed by a sunny and very
pleasant day on Sunday.
The current forecast is in good shape (see discussion below) and
only some minor hourly grid modifications based on the position
of the front are necessary at this time.
79
Previous Discussion:
/Through Sunday/
A robust cold front is progressing through the forecast area early
this afternoon accompanied by a northwest wind shift and
significant dewpoint drop. This boundary still has a low
potential to ignite a few thunderstorms later this this afternoon
within the confines of the CWA, particularly across our far
east/southeast zones. Recent AMDAR soundings out of KDAL indicate
a strong capping inversion still present within the prefrontal
warm sector, and significant daytime heating will be needed to
sufficiently destabilize areas ahead of the front over the next
few hours in order for convection to initiate. The main time
period of interest would be ~4-8pm southeast of a Sulphur Springs
to Hearne line where low PoPs are indicated in the public
forecast. Should any storms be able to develop, they would be
capable of becoming strong given the highly unstable and
moderately sheared airmass in place.
The vast majority of the area has already seen a dry frontal
passage with a prevailing northwesterly breeze of 10-20 mph and
some occasional higher gusts. A brief period of slightly stronger
winds could materialize this evening as the frontal inversion
deepens slightly while 925-850mb flow strengthens to 35-40 kts.
Prior to the boundary layer decoupling around midnight, some of
this momentum may be mixed down to the surface resulting in gusty
northerly winds near 30 mph. Winds will subside to 10 mph or less
by early Sunday morning. Due to cold/dry advection behind the
front, overnight lows will mostly fall into the 40s, and a few
spots could even dip into the upper 30s in parts of North Texas. A
clear and very pleasant Sunday will follow with highs in the 70s
and low humidity.
-Stalley
&&
.LONG TERM... /Issued 300 PM CDT Sat Apr 15 2023/
/Sunday Night Onward/
Light winds and clear skies will promote efficient radiational
cooling processes, yielding a cool start to the work week with
Monday morning low temperatures in the upper 40s and low 50s.
Southerly winds will return and increase in speed on Monday as
high pressure shifts to the east and a surface low develops east
of the Rockies, but moisture will be slow to return across North
and Central Texas. The combination of low afternoon humidity,
breezy southerly winds, and warm afternoon temperatures in the low
80s will result in elevated fire weather concerns west of I-35
Monday afternoon.
A weak shortwave will approach from the west late Monday night
into Tuesday and bring low chances for isolated to scattered
showers and thunderstorms on Tuesday. Low level moisture will be
greatest south and east of the region, which should result in
mostly elevated activity and rainfall amounts below half an inch.
Otherwise, the increased cloud cover will keep highs mostly in
the upper 70s.
The rest of the week will feature periodic rain/storm chances east
of a dry line, which will set up across the Big Country. Elevated
fire weather concerns will also exist Wednesday and Thursday
afternoons as winds shift to the southwest and temperatures soar
into the low 90s and afternoon humidity drops below 25 percent.
Long term guidance continues to struggle with the evolution of the
next upper level system and cold front, with the latest guidance
bringing the system late Thursday rather than Friday. We`ll
continue to side closely with the NBM until there is better
agreement. The weekend will feature cooler temperatures in wake of
the frontal passage.
Garcia
&&
.AVIATION... /NEW/
/00Z TAFs/
A dry post-frontal airmass will remain in place through Sunday,
resulting in VFR conditions at all TAF sites with a most clear
sky.
A breezy northwest wind will continue through the evening in the
14 to 18 knot range with some gusts near 30 knots. Wind speeds
will fall below 12 knots overnight and wind gusts will become
weaker and less frequent. Sustained north winds overnight through
Sunday will be in the 7 to 13 knot range.
79
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 49 73 51 81 59 / 0 0 0 0 5
Waco 47 73 48 78 57 / 0 0 0 0 5
Paris 46 68 45 77 55 / 0 0 0 0 0
Denton 44 72 46 80 56 / 0 0 0 0 5
McKinney 46 71 47 79 57 / 0 0 0 0 5
Dallas 51 74 51 81 59 / 0 0 0 0 5
Terrell 48 71 46 78 57 / 0 0 0 0 5
Corsicana 49 73 49 78 58 / 0 0 0 0 0
Temple 48 75 48 79 57 / 0 0 0 0 5
Mineral Wells 45 75 46 83 58 / 0 0 0 0 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Louisville KY
1158 PM EDT Sat Apr 15 2023
.Forecast Update...
Issued at 1158 PM EDT Sat Apr 15 2023
A line of storms crossing western Kentucky and southwestern Indiana
has been showing a general downward trend in intensity recently with
warming cloud tops on satellite and a slight decrease in lightning.
Outflow has progressed to about ten miles ahead of the convection
and has been generating wind gusts around 40 mph. This outflow will
continue to push into southern Indiana and central Kentucky bringing
gusty winds, though some weakening is expected as it advances
eastward. The storms behind the outflow will likely also continue to
weaken and become more widely scattered, with recent mesoanalysis
and ACARS soundings showing decreasing instability over the past few
hours. Showers and storms are still expected to impact the area
overnight, but severe weather appears to be unlikely. The most
likely area for a stronger storm will be west of I-65 and south of
the Ohio River.
Issued at 908 PM EDT Sat Apr 15 2023
The first cluster of convection across southern IL and western KY
diminished significantly as it approached our CWA earlier this
evening. This was expected due to the less favorable environment
(Less CAPE & Shear) over our region. As a result, things will stay
quiet here until around or just after the Midnight hour as the main
complex of storms approaches the area.
Currently, a pretty healthy line of convection stretches N/S across
the mid Mississippi River Valley ahead of an increasingly negative
tilt shortwave trough and strong cold front. Fairly widespread
Severe Thunderstorm Warnings are being issued in a favorable
environment characterized by 1000-1500 J/KG of CAPE and 30-40 knots
of deep layer shear. It is also worth noting that DCAPE values
currently exceed 1000 J/KG along and just ahead of the line,
supporting the damaging wind threat even more.
This line should still look pretty healthy as it crosses western KY,
and even up to the Wabash River Valley in SW Indiana. However, this
is about where the current instability axis and better deep layer
shear shuts off pretty hard from W to E, and only expect a little
eastward advection of that airmass over the next few hours. Forecast
models continue to agree that the convective line will fall apart as
the storms try to enter our western CWA, and nothing in the current
data suggests otherwise, even if it might still look pretty menacing
as it approaches. That being said, whatever cold pool and collapsing
outflow that the line of storms is able to get going upstream, may
survive into our west where we could have some SPS worthy gusts, or
maybe even a remnant Severe Thunderstorm Warning or two around
Midnight EDT across our western CWA. Will have to monitor pretty
closely, but overall expect a rapid weakening near our western CWA
border, and continued weakening to the I-65 corridor where some wind
gusts may still be possible. Like the SPC Marginal Risk accounting
for that and no changes planned to the forecast at this time.
&&
.Short Term...(This evening through Sunday)
Issued at 320 PM EDT Sat Apr 15 2023
It`s another warm and sunny day, with a cu field covering the region
and sfc temps in the upper 70s and low 80s. We`ve been underneath
shortwave ridging today, with sfc high pressure centered over Georgia
helping to filter warm SSW flow into the Ohio Valley. However, our
dry and warm weather is set end tonight as an amplified trough sweeps
through the Plains, and drags a cold front through tomorrow.
For tonight, the upper trough takes on a negative tilt, but the best
severe potential will be well west of our area. Weakening showers
and storms are expected to push across the forecast area from west
to east through the overnight hours. Waning instability, and a
strengthening low level nocturnal inversion, will help keep storms
weak and elevated across central KY late tonight. WAA ahead of the
front will result in a mild night, with temps still in the 60s by
midnight.
The cold front will be pushing east of I-65 by sunrise tomorrow,
which will result in temperatures following a non-diurnal curve for
areas mostly west of I-65. Warmest temps of tomorrow in that area
will likely occur overnight prior to the cold front passage, and
falling temps behind the front. Best rain chances will shift
eastward with the front by the late morning and early afternoon,
though some lingering light post-frontal showers cannot be rules out
as the trough axis pivots overhead. Daytime heating ahead of the
front may result in some destabilization in our far east, which
could result in some afternoon storms near the I-75 corridor. Timing
remains the biggest factor, but any delay in the front would open
the door for some strong storms tomorrow afternoon in the Bluegrass.
Greater chances still remain east of our area however. Otherwise, we
will likely see breezy winds tomorrow behind the front, with gusts
in the 25-35 mph range through the afternoon.
.Long Term...(Sunday night through Saturday)
Issued at 300 PM EDT Sat Apr 15 2023
Key messages:
* Breezy Sunday night into Monday with gusts as high as 45 mph
* Much cooler Monday with high temps roughly 10 degrees below normal
* Warm weather returns mid week
* Chances for storms Thursday night through Friday night.
Sunday night through Monday:
Trough base of low pressure will be passing through central KY and
southern IN Sunday evening into the overnight Monday, which will
effectively end the precipitation associated with the passing
surface cold front. Model forecasts indicate a deepening surface low
pressure over the Michigan peninsula heading into Monday, which the
surface pressure gradient between 8 and 10 mb across the state will
drive cool west winds between 20 and 30 mph with gusts as high as 45
mph through the day Monday (mainly for locations along and north of
the I-64 corridor). As the storm system moves further north toward
Monday evening, the pressure gradient lessens and the wind is
expected to diminish. Cold air advection behind the front will keep
conditions chilly for the first part of Monday followed by a warm up
as clouds erode and the sun comes out, along with decreasing cold
air advection toward the end of the day Monday.
Monday Night through Wednesday Night:
A broad surface deformation zone begins to spread across the Ohio
Valley Monday night into Tuesday as a warmer air mass approaches the
region. Southerly winds will advect warmer conditions with highs
Tuesday approaching normal for mid April in the lower 60s to mid
70s. The warm front will push north Tuesday night with a chance for
a stray shower (10% chance or less). The warm sector ahead of an
approaching low pressure system will be in place Wednesday with
highs in the upper 70s, although it`s entirely possible highs will
exceed 80 degrees (current NBM guidance for Wednesday`s highs is
between 25th and 50th percentile; many locations have a 60-70%
chance of exceeding 80 degrees).
Thursday through Friday night:
Early indications are that the next chance for rain, and possibly
strong to severe storms, could be Thursday into Thursday night.
Model forecasts diverge a bit on the upper jet stream flow pattern,
but there`s general agreement that stronger upper level winds,
perhaps even a negatively tilted trough, could push into the Ohio
Valley. Model soundings show decent instability (CAPE in excess
of 1200 J/KG) and wind shear (effective inflow and 0-6 km layers
approaching ~30 kts of speed shear, along with some directional
shear component) that could drive some strong to marginally severe
storms Thursday afternoon into Thursday evening. The surface cold
front is expected to pass sometime Friday, but another quick moving
system will bring more chances for rain into Friday night. Rain
chances should end sometime Saturday morning as the cold front
pushes to the east. Stay tuned for forecast updates.
&&
.Aviation...(00Z TAF Issuance)
Issued at 747 PM EDT Sat Apr 15 2023
Convection that had been out over western KY has continued to
diminish early this evening as it moved into a less favorable
environment. Therefore, will not start BWG out with any impacts from
that dying cluster. Otherwise, look for continued VFR with a light
to steady SE to S surface wind and increasing upper sky cover.
Shortly after Midnight and into the overnight hours, look for a mid
ceiling around 4-6 K feet working into the area. In addition, a
weakening complex of showers and storms will also enter the area.
Have the most likely areas for TS mention at HNB/SDF, with it a
little less likely at BWG/LEX. Suppose some very brief IFR could
occur with any heavier shower or storm, but tried to prevail MVFR
ceilings and vis through the pre-dawn and late morning hours.
Ceilings are expected to be below 2K feet for an extended period of
time. One final batch of showers is expected through the late
morning with a notable wind shift along the cold front. Look for
strong WSW winds between 15 and 20 mph, gusting up around 25 to 30
mph through the remainder of the day. Ceilings should improve back
to VFR into the afternoon, but gusts could be quite impactful by
then.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Update...13/BJS
Short Term...CJP
Long Term...MCK
Aviation...BJS
Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
736 PM PDT Sat Apr 15 2023
.SYNOPSIS...15/735 PM.
Very similar weather conditions expected Sunday, then a cooling
trend with strengthening onshore flow and low clouds is expected
Monday and Tuesday. Gusty northerly winds at times are expected
next week with much warmer temperatures by Thursday.
&&
.SHORT TERM (SAT-TUE)...15/733 PM.
A much warmer day today for areas away from the immediate coast
as a weaker and later sea breeze combined with a weak ridge of
high pressure aloft and increased sunshine, resulting in
temperatures climbing well into the 70s across the interior.
Current satellite imagery showing mostly clear skies this evening,
except some patchy low clouds and fog across the Central Coast.
ACARS data from LAX showing marine layer depth around 800 feet
this evening, much shallower than last night. A weak eddy
circulation and slight height falls should allow for some
deepening of the marine layer to around 1500 feet by Sunday
morning, allowing for low clouds and fog to overspread most
coastal and coastal valley areas. HREF and most of the MET
guidance indicating stratus returning to much of the coast and
coastal valleys later than usual and possibly not until sunrise or
later in some areas. Little change in temperatures expected on
Sunday across the interior, but immediate coastal areas may see
slight cooling due to stronger onshore flow and patches of low
clouds possibly lingering into the afternoon. Strengthening
northwest winds expected to impact western portions of the Santa
Ynez Range and south coast of Santa Barbara on Sunday night, as
well as the I-5 corridor on Sunday night, with gusts mostly in the
30 to 40 mph range.
*** From previous discussion ***
A decaying cold front will pass through the area Monday deepening
the marine layer with slowing clearing and cooling temps. Could
even see some drizzle as that boundary passes through the area,
especially in foothill areas. Later in the afternoon and into the
evening, northerly flow will be increasing across the far western
portion of the area leading to decreasing stratus coverage and
gusty winds.
On Tuesday northerly flow will continue to impact the western
portion of the areas but for LA/Ventura Counties additional marine
layer deepening is expected as onshore flow increases to over
8mb and lower level flows continues to be from the southwest,
favoring cloud development. For these areas Tuesday is likely to
be the coolest and cloudiest day with drizzle possible again in
the morning and slow clearing. For SLO and Santa Barbara Counties,
likely stratus-free but breezy and cool. Winds strongest along the
coast where wind advisories may be needed.
.LONG TERM (WED-SAT)...15/216 PM.
Northerly flow will increase and expand eastward into Ventura and
LA Counties Tuesday night into Wednesday as another weak boundary
passes through the area. This will lead to increasing winds
across the I5 corridor region and into the Antelope Valley as well
as southern Santa Barbara County. Whatever marine layer is left
will likely scour out by Wednesday as increasing subsidence
brings drier air to lower levels.
Slightly warmer temperatures expected Wednesday, mainly at lower
elevations with less stratus and downsloping flow off the
mountains counteracting the cooling aloft from the trough passage.
Warming is expected to be more dramatic Thursday and Friday as
northerly flow peaks and ridging aloft is at its strongest with
highs jumping into the 80s in the valleys and mid to high 70s for
the inland coastal plain. Models appear to shifting away from a
Santa Ana wind pattern later next week and sticking with a strong
northerly flow of close to 8mb LAX-BFL and 5mb SBA-BFL. Meanwhile
gradients to the east bottom out near zero. As a result, areas
that are susceptible to northerly winds, such as the areas
mentioned above, will likely see those winds continuing most of
the week and peaking Wed-Fri with periods of low humidities at
times.
Deterministic models are at odds with the upper level pattern next
weekend and ensembles currently are exhibiting higher than normal
spread. The GEFS solutions are trending cooler while a majority
of the EPS solutions maintain warmer weather at least through
Saturday. Either way dry conditions expected to continue, likely
well beyond next weekend.
&&
.AVIATION...16/0019Z.
At 00Z at KLAX, there was a marine layer to 600 feet. The
inversion top was near 2500 feet with a temperature of 17 C.
Low confidence in coast/coastal valley TAFs with timing of
low cigs/vsbys off by up to three hours and one flight category.
There is a 30 to 50 percent chance that VFR conditions prevail
for KBUR and KVNY. There is a 30 percent chance that IFR or lower
cigs/vsbys do form at KSBA as early as 12Z and linger as late as
20Z.
High confidence in desert TAFs.
KLAX...Low confidence in the 00Z TAF, due to certainty in the
timing of low cigs/vsbys overnight. There is a 10 percent chance
that VFR conds prevail. High confidence any east wind component
will be under 8 kts.
KBUR...Low confidence in the 00Z TAF, due to certainty in the
timing of cigs/vsbys. There is a 30 percent chance that VFR conds
prevail.
&&
.MARINE...15/735 PM.
High confidence in below Small Craft Advisory conditions for all
waters through tonight.
Beginning mid to late morning on Sunday, SCA level northwest winds
and steep/choppy seas are expected to become widespread across
zones 670/673, then spreading to zones 645, 676, and western
section of zone 650 by afternoon and early evening. Stronger and
potentially more widespread SCA conditions are likely (80 percent)
Monday evening and night with a 40 percent chance of at least
brief Gales focused across the Outer Waters and near the Channel
Islands. An eddy may develop and shield portions of the Inner
Waters south of Santa Barbara from the strongest northwest winds
Monday into Tuesday, however southeast winds of 10 to 20 kts may
develop, should the eddy form.
Gusty north to northwest winds may sustain at least SCA conditions
focused across the Outer waters and possibly pushing into the
Inner Waters at times for much of the remainder of the week.
The strongest winds next week are expected to develop Tuesday
afternoon and evening, with a 50 percent chance of at least brief
Gale force winds across all the waters, and especially around the
Channel Islands.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect from 3 PM Sunday to 3 PM PDT
Monday for zones 645-650-676. (See LAXMWWLOX).
Small Craft Advisory in effect from 9 AM Sunday to 3 PM PDT
Monday for zones 670-673. (See LAXMWWLOX).
&&
$$
PUBLIC...Gomberg/MW
AVIATION...Munroe
MARINE...Gomberg/Schoenfeld
SYNOPSIS...MW
weather.gov/losangeles
Experimental Graphical Hazardous Weather Outlook at:
https://www.weather.gov/erh/ghwo?wfo=lox