Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 04/11/23
Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
808 PM PDT Mon Apr 10 2023
.SYNOPSIS...10/807 PM.
Low clouds and fog linger at the coasts today into tonight,
otherwise skies will be sunny. High temperatures will continue to
be warmer than normal away from the beaches. It will be cooler
Tuesday and especially Wednesday as lower pressure moves in.
Thursday will be cloudy and cool with a slight chance of showers
across Los Angeles county. A warming trend starts Friday as high
pressure moves in.
&&
.SHORT TERM (MON-THU)...10/757 PM.
Another warm day across the interior today, with high temperatures
climbing well into the 80s. Weak upper level trough of low
pressure pushing through northern California this evening, causing
strengthening onshore flow near the surface. Current LAX-Daggeet
pressure gradient at +5.3 mb as of 7 pm, as compared to +1.1 mb
yesterday evening. Current satellite imagery showing low clouds
and fog quickly surging inland across the coastal plain this
evening. Current ACARS data showing shallow marine layer depth
around 900 feet across the LA Basin, which could result in some
patchy dense fog this evening. Late tonight into Tuesday morning,
expecting marine layer depth to gradually increase due to the
strengthening onshore flow, lowering heights, and a weak eddy
circulation. This will allow for greater low cloud and fog
coverage, including portions of the valleys.
On Tuesday and Wednesday, the upper level trough will continue
to deepen across California, with a continued lowering of heights
during the period. This will lead to a cooling trend the next
couple of days. This will maintain a stronger onshore flow and
deeper marine layer across the region. An influx of colder air
and strengthening northwest winds will likely scour out the
marine layer clouds for areas from Santa Barbara county
northward. For Ventura and LA counties, cross sections showing
a deepening marine layer which could result in some drizzle by
Wednesday morning, and light rain showers by Thursday morning.
Any light rain that does fall across the region is expected to
be less than a tenth of an inch, and mostly focused across LA
county. In addition, there is the potential for upslope flow
producing clouds and a slight chance of rain/snow showers for
interior slopes (mainly near the Kern county line) from Tuesday
night into Thursday. Northwest wind flow will be strengthening the
next couple of days. Wind advisories will likely be needed for
the western portions of the Santa Ynez range and Santa Barbara
south coast where gusts of 35 to 50 mph will be possible. Also,
could see wind advisories needed for the Central Coast by
Wednesday afternoon for gusts in the 35 mph range.
The upper level trough will shift eastward into the Great Basin
by Thursday, with continued gusty northwest winds and cooler
temperatures across the region.
.LONG TERM (FRI-MON)...10/752 PM.
The weak front continues to push through the area early Thursday,
bringing a slight chc of light rain rain to LA county. Strong
onshore flow to the east will develop and wind advisories may be
needed in the Antelope Vly (esp the western foothills) in the
afternoon. The lower hgts and strong onshore flow will make
Thursday the coolest day of the next 7 with highs only in the
lower to mid 60s (6 to 12 degrees blo normal)
Both the GFS and EC deterministic mdls as well as their ensemble
means agree that weak ridging will move over the southern half of
the state on Friday and persist through the weekend. The EC is a
little warmer than the GFS due to having weaker onshore flow to
the east. Most of the ensemble members favor a warmer solution and
the fcst is tilted in the EC`s direction.
&&
.AVIATION...11/0012Z.
At 1813Z at KLAX, the marine layer was 800 ft deep with an
inversion top at 2000 ft and temperature of 23 C.
Low clouds and fog near the immediate coast late this afternoon
will push quickly inland across the coastal plain this evening,
and reach KBUR/KVNY/KPRB by late tonight or early Tuesday morning.
Initially, conditions will mostly be in the LIFR category across
coastal areas, but there is a 20 percent chance of VLIFR
conditions at most coastal TAF sites this evening. As the marine
layer deepens late tonight into Tuesday morning, look for gradual
improvements into IFR/MVFR categories. There should be clearing
to immediate coastal areas by Tuesday afternoon.
KLAX...Moderate confidence in 00Z TAF. LIFR conditions expected
through this evening, with a 20 percent chance of VLIFR
conditions. As the marine layer deepens late tonight into Tuesday
morning, looking for gradual improvements into IFR/MVFR
categories.
KBUR...Moderate to high confidence in 00Z TAF. There is a 30
percent chance that cigs will not reach KBUR during period.
&&
.MARINE...10/205 PM.
In the outer waters, Small Craft Advisory (SCA) level NW winds
are expected develop this evening. There is a 30% chance that
winds and/or seas will reach SCA levels in the northern zone
(PZZ670) as early as this afternoon. Winds and seas will remain at
least at SCA levels across the outer waters thru Fri. There is a
good chance (60% or so) of gale force winds from Tue afternoon
through late Wed night and a Gale Warning has been issued for
that time period. There is even a 20% chance of Storm force gusts
Wed afternoon and evening.
Across the inner waters north of Pt. Conception, there is a 40%
chance of SCA conds this afternoon/evening. SCA conds are likely
during the afternoon thru late evening hours Tue thru Fri.
There is a 30% chance of Gale force winds during the
afternoon/evening hours Tue and Wed.
In the SBA Channel, SCA conds are likely this evening thru late
tonight, mainly across western sections. SCA conds are likely
during the afternoon thru late night hours Tue thru Thu. There is
a 40-50% chance of Gale force winds across western portions of the
channel late Wed afternoon thru late Wed evening.
Across the southern inner waters, there is a 40-50% chance of SCA
conds during the late afternoon through late evening hours Wed
through Thu.
The persistent strong winds will generate large and steep seas
across all waters, with short periods and ample white-capping.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 3 AM PDT Tuesday for
zone 650. (See LAXMWWLOX).
Small Craft Advisory in effect until noon PDT Tuesday for
zones 670-673-676. (See LAXMWWLOX).
Gale Warning in effect from noon Tuesday to 3 AM PDT Thursday
for zones 670-673-676. (See LAXMWWLOX).
&&
$$
PUBLIC...Gomberg/Phillips/Rorke
AVIATION...Gomberg
MARINE...Sweet/DB
SYNOPSIS...Phillips
weather.gov/losangeles
Experimental Graphical Hazardous Weather Outlook at:
https://www.weather.gov/erh/ghwo?wfo=lox
Area Forecast Discussion
National Weather Service Springfield MO
826 PM CDT Mon Apr 10 2023
Key Messages:
1. Warming trend will continue Tuesday through the end of the
week.
2. Higher shower and thunderstorm chances Friday night into
Saturday.
.UPDATE...
Issued at 825 PM CDT Mon Apr 10 2023
Diurnal thunderstorm activity has dissipated across extreme
southeast Kansas and western Missouri due to the loss of daytime
heating and surface-based instability. No additional thunderstorm
activity is expected. Any remaining spotty shower activity over
SE Kansas and western Missouri continuing to dissipate over the
next 1-2 hours.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 145 PM CDT Mon Apr 10 2023
Current Conditions and Synoptic Pattern: Water vapor imagery and
upper air analysis showed a compact shortwave dropping south into
northeast Kansas as an upper ridge begins to build across the
Rockies. 12z KSGF sounding still revealed significant dry mid
level air however the low levels have improved as could be seen
with the extensive cumulus field on visible satellite imagery. The
12z TOP sounding and a 1646Z Kansas City aircraft sounding showed
higher moisture along with 700-800j/kg of MU CAPE. Even higher
instability was present further southwest with 1467j/kg of MU cape
measured on a 1627Z Wichita, Kansas aircraft sounding. The
compact shortwave has ignited isolated showers and storms across
the Kansas City metro in the region of higher moisture and
instability. One item noted on all soundings was the lack of wind
shear. 0-6km shear is roughly 10-15kts therefore storm
organization has been almost pulse like in nature. Steep mid level
lapse rates and the instability have allowed for a few storms to
produce small/marginally severe hail at times.
This Afternoon and Evening: As the shortwave continues to drop
south, so will the thunderstorm potential. An outflow boundary
could be seen moving south along the Kansas/Missouri border,
therefore some isolated storms may develop along this feature this
afternoon, mainly along and west of I-49. Instability drops off
quickly with eastern extent with storms expected to become a
little more widespread across Kansas. A few of the most intense
storms may produce hail up to nickel size and a brief wind gust to
50 mph given the steep lapse rates. Locations east of I-49 may
not see any precip. Precip chances will dissipate with the loss of
daytime heating this evening.
Tuesday: The developing blocking pattern will begin with the
shortwave becoming a closed low over the Gulf Coast and the mid
level ridge spreading into our area. An increase in southwest
winds and partly cloudy skies should allow for temps well into the
70s.
.LONG TERM...(Tuesday Night through Monday)
Issued at 145 PM CDT Mon Apr 10 2023
Wednesday through Friday: Ensembles continue to be in good
agreement that the blocking pattern will become established with
a ridge spreading further into the area and low pressure
remaining along the Gulf Coast. This will allow for dry conditions
and warming temperatures. NBM temperature guidance has a small
spread in variance with highs warming into the 70s. Highs may
approach 80 as early as Wednesday, but more likely Thursday and
Friday given the increasing southwesterly winds.
Weekend and Beyond: Ensemble cluster analysis suggests a
shortwave trough will move into the rockies and plains Friday
into Saturday. There still remains some timing and placement
differences however ensemble clusters support precip over the
area with a frontal passage. Precip chances have now increased
into the 40 to 60 percent range with the highest chances Saturday
as the front moves through. There are also some questions with
moisture depth/quality which will impact storm organization and
strength. This should become better defined as the system moves
closer. The departure of this system will likely knock
temperatures down some for the weekend.
Northwest flow looks to develop behind this system for early next
week however there is large variance in the ensembles with NBM
temperatures showing large spreads in potential temperatures. The
overall synoptic pattern by most ensembles would tend to favor a
cooler and drier pattern which is still supported in CIPS extended
analogs and the CPC outlooks. There is not as strong a signal for
freezing temps then a day or two ago however those with sensitive
plants/agricultural interests will want to stay up on temperature
trends.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 617 PM CDT Mon Apr 10 2023
High confidence in VFR conditions persist through the TAF period.
Isolated showers and storms this afternoon across southeast Kansas
and west central Missouri will slowly weaken into early this
evening before dissipating. This precipitation is expected to
remain north of JLN.
Winds will remain light out of the southeast to south throughout
the TAF period. Some diurnal cumulus is expected again from late
Tuesday morning through afternoon, with the best coverage at JLN
and SGF.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
UPDATE...Rothstein
SHORT TERM...Burchfield
LONG TERM...Burchfield
AVIATION...Rothstein