Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 06/22/22
Area Forecast Discussion
National Weather Service Quad Cities IA IL
650 PM CDT Tue Jun 21 2022
...00z AVIATION UPDATE...
.SYNOPSIS...
Issued at 237 PM CDT Tue Jun 21 2022
Hot and humid weather is focused over the CWA today, as temperatures
have reached the mid 90s with dewpoints in the lower 70s. Heat
index readings of 100 to 107 are common. ACARS soundings over Iowa
show that we have around 3000-3500 CAPE with cap around 800mb, of
about -50 CIN. It appears that additional heating and surface
convergence along the front will be sufficient to get storms going,
and that may be explosive. Storm threats of wind will be the
primary mode, as we have little deep layer shear to support
prolonged severe. Thus, cold pools will be the driver of winds, but
that same process should choke out storm updrafts rather quickly
today and tonight.
&&
.SHORT TERM...(This Evening through Wednesday)
ISSUED AT 237 PM CDT Tue Jun 21 2022
Guidance is quite varied on storm position, so I`ll just nowcast the
existing frontal position eastward with the expected flare up of
storms early this evening. By 9 PM, decaying storms should be moving
over Illinois, and dropping south to Missouri in a non severe mode.
The heat advisory conditions will last until the storms move
through, and with cold pools spreading well out ahead of storms, we
should see relief, even in areas that don`t see rainfall. Spotty
rainfall amounts over 1 inch are likely, but widespread rains are
not expected, due to the pop and drop nature of the storms. If you
get a good rain, you are going to be lucky tonight.
Wednesday, will see dry advection through the day, and while
temperatures will still be warm, in the 80s, we`ll see much drier
air, with dewpoints in the upper 50s, possibly mid 50s.
ERVIN
.LONG TERM...(Wednesday Night through Tuesday)
ISSUED AT 237 PM CDT Tue Jun 21 2022
Key messages:
1) Warm Thursday, but less humid
2) Storm chances Friday and Saturday
3) Very pleasant Sunday afternoon into Tuesday
Wednesday night through Thursday, high pressure will keep the area
dry and mostly clear with comfortable humidity levels. Highs
Thursday will be in the mid 80s to low 90s.
Friday through Saturday, a warm front will lift northeast through
the area followed by a rather strong cold front. Showers and storms
will accompany both fronts, with the highest POPs (40-50 percent)
slated for Friday morning west and generally north of I 80 through
most of Saturday. It remains too early to determine the severe storm
potential. Higher humidity levels will be found across the area on
both days, with temperatures in the 80s Friday and mainly upper 80s
and lower 90s Saturday; with a few mid 80s north and mid 90s central
and southwest. Saturday afternoon the Quad Cities area and locations
south and west will see heat indices in the upper 90s to low 100s.
Sunday through Tuesday, a Canadian dry high pressure area will build
into the region with dew point temperatures slipping into the upper
40s to mid 50s! Highs Sunday and Monday will be in the mid 70s to
low 80s with readings rising into the low to mid 80s by Tuesday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
ISSUED AT 648 PM CDT Tue Jun 21 2022
A narrow line of sctrd thunderstorms will sweep through most of
the TAF sites this evening along a cool front with at least
passing bouts of IFR condtions and gusty winds. Otherwise a VFR
TAF cycle into Wed with southwest sfc winds becoming northwest
by late evening, trending to the north on Wed and increasing
again to around 10 KTS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Heat Advisory until 7 PM CDT this evening for Benton-Buchanan-
Cedar-Clinton-Delaware-Des Moines-Dubuque-Henry IA-Iowa-
Jackson-Jefferson-Johnson-Jones-Keokuk-Lee-Linn-Louisa-
Muscatine-Scott-Van Buren-Washington.
IL...Heat Advisory until 7 PM CDT this evening for Bureau-Carroll-
Hancock-Henderson-Henry IL-Jo Daviess-McDonough-Mercer-
Putnam-Rock Island-Stephenson-Warren-Whiteside.
MO...Heat Advisory until 7 PM CDT this evening for Clark-Scotland.
&&
$$
SYNOPSIS...Ervin
SHORT TERM...Ervin
LONG TERM...14
AVIATION...12
Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
844 PM PDT Tue Jun 21 2022
.SYNOPSIS...21/931 AM.
It will be mostly sunny and warm on Tuesday. A low system off the
coast will bring monsoonal moisture and a chance of showers,
thunderstorms and possible dry lightning Tuesday night through
Wednesday night. Continued inland heat for the rest of the week
with slightly cooler temperatures at the coast as the marine layer
returns.
&&
.SHORT TERM (TUE-FRI)...21/804 PM.
***UPDATE***
Latest satellite and surface observations indicate clear skies
across the district with some clouds ready to stream in from the
south. Latest AMDAR soundings indicate marine inversion quite
shallow, around 700 feet. As for winds, southeast to south winds,
gusting up to 25-35 MPH, are observed across the mountains and
interior valleys.
Overall, current look at latest 18Z and initial 00Z model data
indicates nothing to change previous shift`s thinking for tonight
or Wednesday. Upper low, spinning off of Point Conception, will
allow for increasing moisture and instability to stream into the
area from the south. So, current idea of chance of showers and
thunderstorms tonight through Wednesday evening still looks great.
Looking at model soundings, most of the moisture remains around
10000 feet or higher. So any thunderstorms that develop tonight or
early Wednesday morning will likely be dry, but the storm
activity should become wetter as better PWAT air moves in during
the day on Wednesday. Rainfall totals, if any, look to remain
quite variable. Most areas can expect to receive less than 0.25
inches, but isolated higher amounts are certainly a possibility
during the day on Wednesday.
Current forecast has a good handle on the immediate short term.
So, no updates are planned at this time.
***From Previous Discussion***
Currently, mostly sunny skies are in place for most of the area,
with hot temperatures developing over the interior and valleys.
The desert and mountains are very dry, with Rh`s down in the
upper single digits to teens. However, we are in store for quite
the change as a weak low system just off the coast starts bringing
monsoonal moisture in from the south. Winds have already begun to
shift more southerly. Some breezy, sub-advisory level
south/southeast winds have developed for the Ventura County
mountains, near the I-5 and Hwy 14 cooridor, and the LA County
mountains. Onshore flow increases for the afternoon hours,
limiting heating at the coasts. Will see a large spread in highs
from near 100 over the interior sections to cool 70s at the
coasts.
The coastal low will slowly move further east, bringing a chance
of showers and thunderstorms to the area from late tonight through
Wednesday night. The upper low will be in a favorable position to
bring a low level jet into the VTA/LA county area, some
divergence aloft and decent dynamics. The low also provides upper
level forcing via vorticity advection as instability develops
over the region. Current satellite imagery is starting to show
evidence of this, with a convective cloud field developing over
the Sierra Madre Mountains where models indicate MUCAPE values up
to 800 J/kg. However, moisture may be too limited currently to
support any shower formation. MUCAPE values increase more
significantly overnight (exceeding 1000 J/kg), starting in LA
County, then spreading into Ventura County after midnight.
By early Wednesday, mid-level monsoonal moisture plume starts to
arrive from the south with PWAT values of 1-1.2 inches for LA
County. With the moisture lagging the instability, the highest
chance for dry lightning will be on the edges of the moisture
plume (Therefore, tonight the best dry lightning chances are over
LA/Ventura Counties, and Wednesday morning for eastern SLO and
SB). Western Santa Barbara and western SLO will be on the dry side
of the main moisture plume, so they will be more vulnerable to
dry lightning for potentially the whole day Wednesday. Other
threats with showers/thunderstorms that develop will be brief
downpours and gusty winds supported by high DCAPE values near 1000
J/kg and an inverted V signature in the sounding. The potential
for dry lightning and gusty winds certainly are a fire weather
concern. Precipitation amounts will be highly variable depending
on the location of showers/storms, and could range from 0.01 to
0.25 inches with isolated higher amounts possible. Wouldn`t be
surprised if we see many showers/storms starting out moisture
starved, then produce more rain over time. The eastern San Gabriel
Mountains and Ventura County mountains near Lockwood valley are
favored to see more activity.
Little change in high temperatures into Wednesday, with hot
temperatures inland and cooler values by the coast. However, highs
were warmed 3-5 degrees with the addition of monsoonal moisture by
the coasts. Over interior areas, values should come in slightly
cooler with additional clouds in place and the potential for
convection. Westerly onshore flow returns Thursday which should
help drop values at the coasts, but the interior remains hot into
Friday. As of now, cannot rule out an isolated shower/storm in the
Antelope Valley Thursday, but have not yet added this to the
forecast.
.LONG TERM (SAT-TUE)...21/239 PM.
The latest EC and GFS (both deterministic and mean ensembles) are
in good agreement, therefore somewhat higher confidence in the
extend forecast. Models agree on weak upper level flow with high
pressure dominating the pattern. A ridge builds in over the
western US, dampening the effects of low systems moving into the
Pacific Northwest. Temperatures remain hot over the interior and
cooler at the coasts.
&&
.AVIATION...22/0044Z.
At 2310Z at KLAX, the marine layer depth was 700 feet. The top of
the inversion was near 1400 ft with a temperature of 22 C.
Below confidence in 00Z TAFs, especially after about 12Z when
monsoonal thunderstorm chances are expected to increase from the
south. About a 50/50 shot at low cigs/vsbys vs not for coastal TAF
sites, mainly between 06Z and 15Z. Flight category will likely be
off at times. Dry microburst with gusty and erratic winds will be
possible near stronger TSRA. At least a 10-20% TSRA extend before
and after prob30 groups by at least 3 hours. TAFs without prob30
groups also have a 10-20% TSRA, mainly after 16Z.
KLAX...Low confidence in 00Z TAF. 50% chance VFR conds prevail
through the period. Cannot rule out VCTS as early as 06Z. Dry
microburst with gusty and erratic winds will be possible near
stronger TSRA. There is a 20 percent chance east wind component
will at least briefly reach 8 kts, mainly between 08-18Z with the
onset of monsoon moisture and any associated TSRA.
KBUR...Moderate confidence in TAF through 08Z with low confidence
related to monsoon moisture and possible TSRA for the remainder of
the TAF.
&&
.MARINE...21/841 PM.
A shallow marine layer will likely support patchy dense fog
across most of the waters overnight and possibly into Wednesday
morning. Isolated thunderstorms may spread from the southern
waters late tonight north through the inner waters and perhaps
eastern portions of the outer waters Wednesday morning through
Wednesday afternoon or early evening. Locally gusty winds and
choppy seas are possible near stronger thunderstorms. The Marine
Weather Statement was updated to include the threat for patchy
dense fog.
A weak eddy with southerly winds into Wednesday will give into
more typical onshore winds through much of the weekend. Small
Craft Advisory (SCA) level winds and seas are not expected across
the coastal waters through at least Saturday morning. A medium
period south swell of 2 to locally 4 feet may build into the
waters early next week, compliments of Tropical Cyclone Celia.
&&
.BEACHES...21/105 PM.
A weak weather system will draw up some moisture across the
forecast area tonight and Wednesday, causing a slight chance of
thunderstorms. The risk begins after midnight tonight and
continues through Wednesday. Anyone planning to visit the
beaches on Wednesday need to closely watch the weather conditions.
If thunder roars, go indoors.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.
&&
$$
PUBLIC...Phillips
AVIATION...Munroe
MARINE...Munroe
BEACHES...Sweet
SYNOPSIS...EPS
weather.gov/losangeles
Experimental Graphical Hazardous Weather Outlook at:
https://www.weather.gov/erh/ghwo?wfo=lox