Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/05/22
Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
759 PM PDT Thu Aug 4 2022
Monsoon showers and thunderstorms will be possible over parts of
northern Ventura and Los Angeles Counties mainly Friday afternoon,
then again next week. A warming trend is expected across southwest
California over the weekend with highs near to slightly above
normal in most areas.
.SHORT TERM (THU-SUN)...04/757 PM.
Better coverage of monsoon showers and thunderstorms this
afternoon with the heaviest activity north of Lockwood Valley Road
in northern Ventura County, and east of Lancaster in the Antelope
Valley. Radar-based rainfall estimates were over 1 inch for both
areas and possibly up to 2 inches near Pine Mountain Club. Sparse
rain gauges in these areas did not capture nearly this amount and
there were no significant flood reports. There was also a few
pictures of a landspout when cells developed near Littlerock this
afternoon. Instability remains along the Kern County line this
evening and moderate showers were about 30 miles north of the
county-line rotating over that area from the east. Will continue a
convective threat for that extreme northern border area until 06Z,
however, the air mass continues to stabilize and expect an end to
any thunderstorm potential for the remainder of the night. There
are plenty of mid to high level clouds over the region and this
has also hampered instability this evening along with playing
havoc with the stratus along the coast south of Pt Conception.
Still expect plenty of low clouds on the Central Coast through
Friday morning and a chance of clouds or fog redeveloping in
other places of the Ventura and south Santa Barbara County coasts
HREF data and HRRR indicate just an isolated cell developing
Friday afternoon over the northeast corner of the Antelope Valley
around 1-2pm that quickly exits northward. There remains plenty of
higher PWATs and some resemblance of a weak vorticity off the
coast that could still bring a quick shower or thunderstorm to the
northern mountains tomorrow, so will leave that in the forecast.
Southwest flow quickly returns behind this feature late Friday
with PWATs and monsoon moisture decreasing through the weekend.
***From Previous Discussion***
A little more active today with a thunderstorm along the
Kern/Ventura County border and plenty of storms well to the south
and east, including a huge area over the northern Baja mountains
that is sending a giant high cloud shield towards LA County. We
should continue to see storms developing over the mountains with
the afternoon heating providing additional lift. And increasing
high clouds from the southeast as that cirrus shield moves over
A weakening easterly wave moving into California from AZ may
provide enough energy to maintain showers and possible storms
across LA County overnight, though models have backed off that
idea somewhat in recent runs. Not as sold on it now but wouldn`t
be surprised to see a few showers and possibly even a
thunderstorm over the LA County coast/valleys this evening into
the overnight hours. Somewhat better chances though over the
eastern mountains and Antelope Valley.
Friday still has the potential for being an active thunderstorm
day despite rapidly decreasing PW`s and a shift of the upper level
flow from southeast to southwest. Forecast soundings over the
LA/Ventura mountains had considerably higher CAPE values than
today and 850 dewpoints from 10-14c which is about the same as
today. Most of the hi res models and ensembles show less activity
than today, but there is the potential for some strong cells and
periods of heavy rain. Not much chance of storms south of the
mountains with the steering flow from the southwest.
After Friday PW`s drop off quickly and air mass stabilizes so the
weekend forecast remains thunderstorm free. With less moisture in
the air, fewer clouds, strong high pressure aloft, and weakening
onshore flow, most areas should see a warming trend Sat/Sun with
highs in the lower 100s in the warmer coastal valleys and mid to high
80s across the inland coastal plain. Marine layer will be less
disrupted with no debris clouds drifting through so likely a more
solid stratus coverage with areas of dense fog near the coast.
.LONG TERM (MON-THU)...04/207 PM.
Monsoon moisture returns next week with showers and thunderstorms
possible over the eastern mountains most days. Models do show
signs of a couple easterly waves moving through, mainly Monday
and again Thursday so can`t rule out overnight convection or
showers/storms over the coast/valleys at times, mainly LA County.
Onshore flow remains pretty light most of next week but
temperatures may fall slightly with increased clouds and moisture
aloft. Overall, pretty typical August conditions across southwest
At 2344Z at KLAX, the marine layer was 800 ft deep. The top of
the inversion was at 2500 ft at a temperature of 25 C.
High confidence in KPRB, KBUR, and KVNY.
Moderate confidence in KWJF and KPMD. There is a 20% chance of
brief thunderstorms through 12Z. Any thunderstorm that develops is
capable of producing brief heavy rain and reduced visibility,
gusty and erratic winds, and dangerous lightning.
Low confidence in coastal TAFs, especially for LA and Ventura
County sites. High clouds will disrupt the marine layer, so there
is a 40% chance of IFR cigs developing any time after 03Z for
sites without cigs forecast. There is a 40% chance of no low
clouds for KSBA. Arrival of low clouds at KSBP and KSMX may be off
by an hour.
KLAX...Low confidence in TAF. There is a 40% chance of IFR cigs
anytime after 03Z. Any east wind component will be under 5 kt.
KBUR...High confidence in TAF. There is a 10% chance of a brief
isolated shower or thunderstorm through 06Z.
High confidence in winds and seas remaining below Small Craft
Advisory (SCA) level through Friday morning. There is a 50-60%
chance of SCA level winds from Point Conception to San Nicolas
Island late Friday afternoon through evening. If SCA level winds
do develop, there is a chance they may spread into the southern
and western half of the Santa Barbara Channel. SCA level winds
are also possible across the waters between Anacapa and Catalina
Islands. On Saturday, gusty NW winds become more widespread to the
north across the outer waters along the Central Coast. The best
chance for SCA level winds will be from Point Conception to San
Nicolas Island (including the southern/western half of the Santa
Barbara Channel) once again and will likely be stronger than
Friday. SCA level winds will likely continue across all the waters
from the Central Coast to San Nicolas on Sunday and potentially
into the early part of the next work week.
PZ...Small Craft Advisory in effect from 4 PM Friday to 3 AM PDT
Saturday for zones 673-676. (See LAXMWWLOX).
Experimental Graphical Hazardous Weather Outlook at:
Area Forecast Discussion...UPDATED
National Weather Service Portland OR
857 PM PDT Thu Aug 4 2022
Updated Short Term and Aviation sections
.SYNOPSIS...Upper level trough will push east Friday allowing
temperatures to climb back into seasonable norms. Ridging will build
north across the Pacific NW and temperatures will climb over the
weekend. Temperatures are expected to cool Tuesday.
.DISCUSSION...EVENING UPDATE: At 0330Z water vapor imagery revealed
an upper level trough situated over British Columbia and Alberta
extending south through much of the Pacific Northwest. A dry slot/jet
streak could be seen over Washington and far northwest Oregon. The
monsoonal moisture continues to be shunted over the Great Basin with
some thunderstorm activity slipping into far southeast Oregon.
Primary tweaks to the forecast include a little less sky cover
tonight, even for the coast. Also, with dew points generally in the
mid 40s to lower 50s, have lowered min temps in many areas. Some of
the normally cooler interior valleys will likely see mid to upper
40s. Elevated valley bottoms in the Lane County Cascades may drop
into the lower 40s. The remainder of the forecast looks to be in good
REMAINDER OF DISCUSSION FOLLOWS: Tonight through Wednesday...Models
show a shortwave spinning off the parent low over British Columbia
and dropping back towards the Pacific NW Friday morning. This will
keep a slight onshore component along the coast and will help to
moderate temperatures slightly on Friday.
Nonetheless, with mostly clear skies Friday morning and boundary
layer winds shifting northerly by the afternoon, high temperatures
will trend back into seasonable norms. The 12Z model guidance shows
the trough departing the region sometime on Saturday allowing the
upper level ridge over the Desert Southwest to build north. Weak
offshore flow will bring drier, warmer air west and with 850mb temps
climbing into the mid teens daytime highs will build into the low
90s across the Willamette Valley.
Medium range guidance continues to point to Sunday as the warmest
day in this upcoming stretch as the ridge axis builds directly
overhead and pushes 500 mb heights to around 588 dam while temps
climb back to around 19-22C. This should correspond to afternoon
highs at least in the mid 90s, with NBM probs for reaching 100
degrees continuing to trend upward to around 50 percent in most
valley locations. The forecast remains more uncertain beyond Sunday
as the persistent cutoff low begins to approach the coast again early
next week. Something that may disrupt the temperature forecast is the
transport of smoke aloft over the weekend. N-NE winds as depicted by
the HRRR smoke model shows the potential for haze across the area
Saturday morning from wildfires across Washington. If there are
enough aerosols then temperatures may be cooler than expected.
Temperatures are likely to settle back into the 80s by Tuesday as
most guidance depicts the low starting to move inland, but
confidence remains low given the models` struggles to handle this
feature dating back to last week. Lastly, the conceptual model of
increasing southerly flow and mid level moisture ahead of the
approaching trough would seemingly favor at least some thunderstorm
potential in the central OR Cascades by Monday and Tuesday, but
ensemble solutions have notably been been lacking in depicting any
thunderstorm potential to this point. That will be one more thing to
monitor in the coming days as the evolution of the pattern comes
into clearer focus. -BMuhlestein/CB
.AVIATION...06Z TAFs: Low level northerly flow continues Thursday
night, with VFR flight conditions continuing everywhere as of
04z Friday. Such will be the case inland throughout the TAF
period, while there is a bit more uncertainty in what will occur
along the coast. There, guidance is giving around a 25-40% chance
for low stratus to result in MVFR or lower flight conditions
during the 11-17z time period. By midday, northerly winds will
pick back up and may gust over 20 kts at times along the coast.
For detailed Pac NW aviation weather information, go online to:
KPDX AND APPROACHES...VFR conditions are expected through the end
of the TAF period. Northwest winds may gust to 15 kts or higher
in the mid afternoon through late evening Friday. Bumgardner
.MARINE...High surface pressure offshore and thermally induced low
pressure inland will continue the northerly winds through the
weekend. This set up will bring a period of northerly Small Craft
Advisory winds for all zones. Small Craft winds will start for zones
PZZ270 and PZZ255 tonight, followed by zone PZZ270 Friday morning
with PZZ250 coming online Friday afternoon. These Small Craft winds
are expected to continue through late Friday night/early Saturday
Seas will remain around 5 to 8 ft at 9 to 11 seconds with a
dominant northwesterly swell with the highest seas expected in
PZZ275. There is also a small, 1 to 2 ft, southerly swell around
14 seconds. /42
For information about upcoming marine zone changes, go online to:
OR...Heat Advisory from noon Sunday to 8 PM PDT Monday for Central
Columbia River Gorge-Greater Portland Metro Area-Upper Hood
River Valley-Western Columbia River Gorge.
WA...Heat Advisory from noon Sunday to 8 PM PDT Monday for Central
Columbia River Gorge-Greater Vancouver Area-Western
Columbia River Gorge.
PZ...Small Craft Advisory from 2 PM to 11 PM PDT Friday for Coastal
waters from Cape Shoalwater WA to Cascade Head OR out 10 nm.
Small Craft Advisory until 3 AM PDT Saturday for coastal waters
from Cascade Head OR to Florence OR out 60 nm.
Small Craft Advisory from 2 AM Friday to 3 AM PDT Saturday for
Waters from Cape Shoalwater WA to Cascade Head OR from 10
to 60 nm.
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Area Forecast Discussion
National Weather Service Springfield MO
631 PM CDT Thu Aug 4 2022
1. Isolated showers/storms possible later this afternoon into
2. Isolated showers and storms possible again Friday afternoon
into early Friday evening over the eastern Ozarks.
3. Heat Advisory issued for Friday afternoon into early evening.
Excessive heat continues into this weekend.
.SHORT TERM...(This evening through Friday)
Issued at 250 PM CDT Thu Aug 4 2022
Latest satellite imagery shows cloud cover from the
overnight/morning convection having pushed south of the CWA, with
an area of cumulus/stratocumulus having developed across central
Missouri. Some of this cumulus is beginning to look a bit more
agitated in the vicinity of Pulaski/Phelps/northern Texas
counties. A stationary front was also observed across central
Temperatures have rebounded nicely into the 80s across most of
the area, with Joplin having reached 90 degrees as of 2 PM. Expect
afternoon high temperatures to top out in the mid 80s to low 90s,
with the hottest temperatures across far SE Kansas and western
Missouri. These temperatures were dropped a couple degrees from
earlier forecasts due to the lingering cloud cover this morning.
Nonetheless, heat index values in the low 100s will occur in the
aforementioned hottest areas, with the remainder of the area
generally seeing heat index values top out in the mid to upper 90s
For late this afternoon and evening, the humid airmass will
continue to linger over the area with progged PWATs of 1.4-1.8
inches. RAP and model thermal profiles suggest 1800-2500 J/kg of
uncapped surface-based CAPE will be available during this
timeframe with weak mid-level troughing over the eastern
Ozarks/Mississippi River Valley acting as a catalyst for isolated,
sub-severe pulse showers and thunderstorms. Coverage and intensity should
be overall limited given substantial dry air above 800 mb and poor
lapse rates aloft in a 20-25 knot effective bulk shear regime.
HREF/Hi-res guidance further support this limited coverage and
relegate the best chances for convective development to east of
Highway 65, particularly over the eastern Ozarks.
Warm temperatures continue into tonight, with lows around 70-74
degrees. Several models are indicating the potential for some
low stratus or shallow fog over the eastern Ozarks tonight given
the lingering humidity and moisture in this area that saw several
inches of rain earlier today. The signal for dense fog is not
present at the moment, but will need to monitor forecast trends
closely for any changes.
Heat begins to ramp up on Friday as the upper-level ridge builds
into the Central Plains. Progged 850 mb temperatures of 22-24
degrees C support high temperatures in the mid to upper 90s over
much of the area, though some scattered cloud cover and additional
isolated afternoon/early evening showers and storms could form over
the eastern Ozarks and lead temperatures to be a few degrees
cooler in our east if this scenario comes to fruition. As a
result, have issued a Heat Advisory for our SE Kansas and western
Missouri Counties where confidence is highest that high humidities
and hot temperatures will combine to produce heat index values in
the 103-107 degree range. This Heat Advisory is in effect from
1 PM - 8 PM.
.LONG TERM...(Saturday through Thursday)
Issued at 250 PM CDT Thu Aug 4 2022
Excessive heat will continue into Saturday and Sunday as the
upper-level ridge slides over the central Plains and central
CONUS. 850 mb temperatures of 22-24 degrees C will persist over
the area, with heat index values of 100-107 in the forecast due to
high temperatures likely in the mid to upper 90s extending from
southeast Kansas into the Rolla area. Temperatures in the low to
mid 90s are more likely for the eastern Ozarks and south- central
Missouri through the weekend. We did introduce some very low PoPs
(around 20%) over far south-central Missouri for Saturday
afternoon due to the influence of a weak upper-low over Kentucky
nudging underneath the ridge. Forcing looks weak and possibly too
far east with this feature, so chances for any diurnal convection
look unlikely at the moment.
Late Sunday - Tuesday night:
Fairly good agreement in an upper-level trough traversing the
northern periphery of the ridge and pushing east across the upper
Midwest and Great Lakes from late Sunday into Tuesday. This
feature would bring an associated surface cold front into and
through the Missouri Ozarks region, which could lead to additional
chances (currently 30-50%) during this timeframe. The WPC Cluster
Analysis Tool has a ECMWF-heavy cluster that has less rain chances
for Sunday, mainly due to later arrival of the cold front.
However, all 4 clusters have at least some precipitation across
the area for Monday and Tuesday, with a mixed signal for Tuesday
night/Wednesday morning depending on how quickly the front moves
south of the area. Still several days out, but GEFS precipitation
probabilities do not point to a washout at the moment.
Probabilities for greater than 0.25" of rain are 30-50% over
south-central Missouri and less elsewhere. Greater than 0.5" is
less than 30% for the same area, and 1.0" or greater probabilities
are almost non-existent.
Mid-Late next week:
The NBM temperature forecast indicates a slight "cooldown" into
mid to late next week behind the cold front with slightly drier
dewpoints, as well. Therefore, current forecast highs are for the
mid 80s to isolated mid 90s during this timeframe, though some
differences in the upper-level pattern/ridge are creating a bit of
uncertainty in these temperatures as reflected in wider NBM
Looking ahead to mid-August:
CIPS Extended Analog guidance continues to point to a general
above average trend in temperatures as we approach mid-August with
also generally drier than normal precipitation. This is further
supported by the CPC 8-14 outlook. While recent rainfall may
reduce the severity of drought conditions for portions of the
area, a return of this trend of warmer and drier conditions is
expected to keep drought conditions going through August.
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Pilots flying in and out of the southwest Missouri airports can
expect fair weather VFR conditions over the next 24 hours.
Residual cumulus clouds will eventually clear out of the region
this evening as light and variable winds at the surface evolve.
A summertime high pressure system will move closer to the Ozarks
tomorrow while very dry mid level air spreads in. This will limit
the amount of thunderstorm activity that develops tomorrow
afternoon. However, it`s possible that a couple of thunderstorms
develop near the Branson airport, but not likely.
MO...Heat Advisory from 1 PM to 8 PM CDT Friday for MOZ066-067-077-
KS...Heat Advisory from 1 PM to 8 PM CDT Friday for KSZ073-097-101.