Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 04/04/19
Area Forecast Discussion
National Weather Service Houston/Galveston TX
1000 PM CDT Wed Apr 3 2019
.DISCUSSION...
Upper trof making its way into western parts of TX & OK will
continue moving ewd tonight into Thurs. Llvl jet has strengthened
in advance and is transporting deeper Gulf moisture into the
area. Latest aircraft soundings show nearly saturated llvls with a
cap situated between 700-600mb. This generally matches up w/
available guidance fairly well which also depicts the cap holding
its ground overnight. So, would mainly anticipate periods of
mostly -ra throughout the night w/ low (if any) chances of tstms.
Temps shouldn`t drop all that much more from what we`re seeing
now.
Grids have a pretty good handle on things and just matched grids
w/ trends and obs for the update. We did hit the sea fog
development & coverage a bit harder as we`re starting to see some
development off the Matagorda coast. Recent cool spell lowered
nearshore water temps back into the mid 60s. Warmer airmass will
be moving over the cooler shelf waters. Sea fog should expand ewd
to off the Galveston coast Thursday then move northward into the
bay Thursday night and will probably be an issue thru the weekend
for mariners. 47
&&
.PREV DISCUSSION... /ISSUED 644 PM CDT Wed Apr 3 2019/
AVIATION...
Radar is picking up on some light showers moving into
the western half of the FA at this time...with CIGS also lowering
as moisture levels continue to deepen. Have sped up the timing of
these falling CIGS a bit with the update based on current
obs/model trends. This cloudy/slightly wet pattern should continue
into tomorrow as an upper level disturbance approaches from the
SW. Strong capping should limit thunderstorm development and will
keep with the VCSH wording for now. CIGS are expected to fall
again by tomorrow evening across much of SE TX with sea fog a
possibility at the coast. 41
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 71 62 83 65 82 / 20 50 40 10 10
Houston (IAH) 70 63 80 67 81 / 20 50 60 10 20
Galveston (GLS) 68 65 73 67 74 / 20 50 50 10 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 6 AM CDT Thursday for
the following zones: Coastal waters from Freeport to
Matagorda Ship Channel TX out 20 NM...Coastal waters from
High Island to Freeport TX out 20 NM...Galveston Bay...
Matagorda Bay...Waters from Freeport to Matagorda Ship
Channel TX from 20 to 60 NM...Waters from High Island to
Freeport TX from 20 to 60 NM.
&&
$$
Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
804 PM PDT Wed Apr 3 2019
.SYNOPSIS...03/647 PM.
Mostly cloudy skies are expected tonight as an upper level trough
approaches the state. Clouds will remain across the area with
chances for light rain on Thursday and Friday, mostly north of
Point Conception. A ridge of high pressure will build through the
weekend into Monday bringing dry weather and warming temperatures.
&&
.SHORT TERM (WED-SAT)...03/803 PM.
***UPDATE***
Overall, a quiet evening across the forecast area. Latest
satellite and surface observations indicate partly to mostly
cloudy skies across the area with a mixture of low and high
clouds. The latest AMDAR soundings indicate a moist layer up
to 5000 feet with a weak inversion based around 1600 feet. So
with continued onshore gradients, expect partly to mostly cloudy
skies to persist through the overnight hours. Additionally, given
the depth of the moisture and onshore gradients, there could be
another round of some light rain across the San Gabriel Valley
overnight. Also, as a weak frontal system approaches the area
overnight, there could be an outside chance of some light showers
across northwest San Luis Obispo county overnight.
Otherwise, nothing really of note for the immediate short term as
winds are generally light. Looking at the current forecast, the
immediate short term looks good. So, no significant updates are
planned at this time.
***From Previous Discussion***
A deep moist layer around 4500 ft deep prevailed over SW CA this
afternoon, with varying amounts of stratocu noted across the area,
especially from the coast to the vlys and coastal slopes. Varying
amounts of hi clouds continued to move over the forecast area as
well. Little change can be expected thru sunset, with generally a
mix of clouds and sun persisting. Temps will be about 4 to 8 deg
below normal for most areas today. Highs in the warmest coastal and
vly areas should reach the mid to upper 60s.
A relatively weak upper level ridge over srn CA this afternoon will
move E tonight with an upper level trof over the E Pac expected to
approach the CA coast thru Thu. This trof will move inland Thu night
followed by another upper level trof on Fri. This second upper level
trof will move E Fri night with upper level ridging building along
and just off the CA coast on Sat.
The deep moist layer will continue over the area tonight into Thu.
It looks like there should be enough low level lift for light rain
to occur over the San Gabriel Vly into the coastal slopes of the San
Gabriel Mtns Thu morning. Some rain will also be possible over NW
SLO County Thu morning, with the chances of rain spreading across
most of the forecast area thru Thu afternoon as the upper level trof
moves in. A persistent moist low level onshore flow and the second
upper level trof on Fri will keep varying chances of showers over
much of the forecast area Thu night thru Fri night, with the best
chance of rain along the Central Coast Fri afternoon. There may be a
few leftover showers over western SLO County Sat morning, otherwise
dry weather with varying amounts of clouds should prevail on Sat
across southwestern CA as the upper level ridge starts to build into
the area.
Expected precip totals Thu thru Fri night will generally be on the
light side. For L.A./VTU Counties, rainfall should be 0.10 inch or
less, with up to 0.20 inch in the mtns. SBA/SLO Counties should
see about 0.15 inch or less, except locally up to 0.50 inch in the
coastal hills of northwestern SLO County. Snow levels will be
around 6500 to 7000 feet, with perhaps up to an inch or two of
snow possible above 7000 feet, especially for the VTU County mtns.
Temps are expected to continue to be several degrees cooler than
normal on Thu and Fri, then warm to near normal overall on Sat.
Highs in the warmest vlys and coastal areas should be generally in
the mid 60s to around 70 for Thu and Fri, then warm to the upper 60s
to lower 70s on Sat.
.LONG TERM (SUN-WED)...03/151 PM.
The upper level ridge will build into srn CA Sun and Mon, with 500
mb heights increasing to near 586 dm on Sun, and to near 588 dm on
Mon as per the GFS (the EC was slightly lower).
Strong northerly offshore gradients are forecast by the GFS
especially by early Mon. Periods of gusty N winds will likely prevail
across the SBA County mtns and S coast, with gusty NW winds in the
VTU/L.A. County mtns especially along the I-5 corridor. Wind
advisories will likely be needed between Sun and Mon, however
winds could possibly approach high wind warning thresholds at
times.
Varying amounts of hi clouds can be expected during the period for
partly cloudy to occasionally mostly cloudy skies. Temps with the
offshore flow and upper level ridging Sun and Mon are expected to be
significantly above normal with highs in the warmest vlys and
coastal areas reaching the upper 70s to mid 80s Sun, and 80s to
around 90 on Mon.
The GFS keeps some upper level ridging over swrn CA on Tue while the
EC breaks the ridge down quickly Mon night with a rather sharp upper
level trof pushing into central CA on Tue. The EC was forecasting
some rain to move into parts of the forecast area late Mon night and
Tue, but opted to lean more toward the GFS and kept any POPs below
15 percent. Temps on Tue are expected to be cooler but still a bit
above normal with highs in the warmest vlys and inland coastal areas
in the upper 70s to mid 80s.
Wed will either have weak upper level ridging over the area as
per the EC or an upper level trof as per the GFS. Leaned toward a
model blend for Wed with dry and cooler weather along with good
onshore flow. Highs in the warmest vlys and inland coastal areas
Wed are forecast to reach the 70s to near 80.
&&
.AVIATION...03/2329Z.
At 2300Z, there was no marine inversion at KLAX. However, there
was a moist layer around 040 deep.
Overall, low confidence in 00Z coastal and valley TAFs, but high
confidence in 00Z desert TAFs. For coastal/valley sites, deep
moist layer and moderate onshore flow may allow for development
of MVFR CIG restrictions overnight, but confidence in development
or duration of CIG restriction at any site is low to moderate. By
late Thursday morning, weak front will bring the chance of light
showers to sites north of Point Conception.
KLAX...Low confidence in 00Z TAF. There is a 40% chance that MVFR
CIGs will not develop during the TAF period.
KBUR...Low confidence in 00Z TAF. There is a 40% chance that MVFR
CIGs will not develop during the TAF period.
&&
.MARINE...03/803 PM.
For the Outer Waters...moderate to high confidence in current
forecast. Through Friday, high confidence that winds and seas will
remain below Small Craft Advisory (SCA) levels. For Saturday
through Monday, northwest winds will increase with moderate
confidence in winds reaching SCA levels, especially Sunday and
Monday.
For the Inner Waters north of Point Sal...moderate to high
confidence in current forecast. Through Saturday, high confidence
in winds and seas remaining below SCA levels. For Sunday and
Monday, moderate confidence in winds reaching SCA levels each
afternoon and evening.
For the Inner Waters south of Point Conception...moderate to high
confidence in current forecast. High confidence in winds and seas
remaining below SCA levels through Friday. For Saturday through
Monday, moderate confidence in SCA level winds across the western
half of the Santa Barbara Channel while winds and seas remain
below SCA elsewhere.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.
&&
.HAZARD POTENTIAL OUTLOOK (SAT-WED).
Near record high temperatures possible Mon, especially near the
coast. Gusty N winds possibly to near warning levels can be
expected at times Sun thru Mon, especially for the mtns and SBA
County S coast.
&&
$$
PUBLIC...Sirard
AVIATION...RAT
MARINE...RAT
SYNOPSIS...Stewart
weather.gov/losangeles