Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 11/07/21

Area Forecast Discussion

National Weather Service Columbia SC

 820 PM EDT Sat Nov 6 2021

.SYNOPSIS...
Low pressure will begin tracking away from the southeastern
US tonight and slowly push further into the Atlantic Sunday
allowing dry air to return to the area Sunday morning. Ridging
and moderating temperatures will be over the region for much of
next week with rain chances return late in the week.

&&

.NEAR TERM /UNTIL 7 AM SUNDAY MORNING/...
Low pressure off the GA Coast continues to slowly move northward
with rain along the SC Coast and Coastal Plain. Overnight the
low will begin accelerating to the northeast with the rain
moving northward along the coast. Over the forecast area a
complex scenario continues to unfold with a very tight moisture
gradient in place. The strong and gusty northerly winds continue
advecting dry air into the area resulting in pwat values ranging
from one inch or greater in the eastern Midlands to around one
half inch in the western Midlands. This continues to limit the
westward extent of the rain with CAE WSR-88D continuing to show
showers dissipating as they move into the central Midlands and
CSRA. This trend will continue through the overnight hours with
pops falling toward daybreak as the low begins moving away from
the region. Winds will remain strong and gusty...especially in
the eastern Midlands where the pressure gradient remains
tightest. Current CAE VWP shows 25 knots at 1 kft with 35 knots
at 2 kft. With better mixing over area lakes will keep the lake
wind advisory in place. Overnight lows with the extensive clouds
and mixing range from the lower 40s in the western Midlands to
the mid 40s in the eastern Midlands.

&&

.SHORT TERM /7 AM SUNDAY MORNING THROUGH TUESDAY/...
A coastal low pressure system slowly moves farther offshore on
Sunday. Clouds will decrease during the day and northerly winds will
gradually diminish. High temperatures will be much warmer with ample
afternoon sunshine.

High pressure aloft builds over the Southeast U.S. Monday through
Tuesday with mostly clear skies and above normal high temperatures
for mid November. Expect highs in the lower to mid 70s and lows in
the lower to mid 40s.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
High pressure aloft remains in place Tuesday Night through
Wednesday, before the pattern transitions later in the week. A
strong upper level trough is forecast to push into the Eastern U.S.
Veterans Day through Saturday. The ensembles differ significantly on
the depth of this upper trough. This variance in model solutions
impacts the magnitude of potential cold air intrusion into The
Midlands and CSRA next weekend. The best estimate this far out is a
chance of showers Friday through Saturday and a modest cooling trend
on Saturday.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Closed low and surface low pressure offshore NE FL will
continue to move slowly to the ENE. Wrap around moisture
affecting mainly the coastal plain, but some light rain making
into our FA. MVFR CIGS affecting OGB and are close to CAE/CUB,
and will expect this cloud cover to work west and affect our TAF
sites overnight. Based on model data, CAE VWP, and latest AMDAR
soundings, decided to include mention of LLWS. The system will
move out Sunday, with a return to VFR but continued breezy.

EXTENDED AVIATION OUTLOOK...No significant impacts to aviation
expected Sunday night through Wednesday except some late
night/early morning shallow ground fog possible at fog prone AGS
and OGB Tue/Wed.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
GA...Lake Wind Advisory until 2 PM EST Sunday for GAZ040-063>065-
     077.
SC...Lake Wind Advisory until 2 PM EST Sunday for SCZ016-018-
     020>022-025>031-035-037-038-041-115-116-135>137.

&&

$$



Area Forecast Discussion

National Weather Service Los Angeles/Oxnard CA

 805 PM PDT Sat Nov 6 2021

.SYNOPSIS...06/159 PM.

A cooling trend will continue through Monday as a couple of
weather systems move through northern California. Rain is
expected across the Central Coast Tuesday but very little rain, if
any, will make it to Ventura or Los Angeles County. A significant
warming trend and gusty Santa Ana winds are expected mid to late
next week.

&&

.SHORT TERM (SAT-TUE)...06/804 PM.

***UPDATE***

Latest satellite and surface observations indicate some patchy
stratus/fog across the coastal plain, south of Point Conception,
with mostly clear skies elsewhere. Current AMDAR soundings
indicate marine inversion around 1200 feet deep across the LAX
Basin (and likely a bit more shallow north of Point Conception).
There are some locally gusty northerly winds across the Santa Ynez
Range with Gaviota and Refugio gusting 30-35 MPH.

For the immediate short term, the forecast looks in very good
shape. Models indicate some lowering of H5 heights overnight which
should allow the marine inversion to deepen a bit overnight (as
onshore flow continues to the east). So, will expect widespread
stratus/fog overnight across the coastal plain south of Point
Conception with decent penetration into the coastal valleys of
Ventura/LA counties. There may be some localized dense fog across
the valleys overnight, but most visibilities should remain above
dense fog levels. North of Point Conception, some weak
northeasterly flow should keep stratus at bay with only some very
patchy stratus/fog overnight along the coast. Other than the
stratus and fog, skies should remain mostly clear overnight. As
for winds, do not anticipate any strengthening overnight, so
gusts near 35 MPH will continue across southern SBA county
overnight.

Overall, forecast has very good handle on the immediate short
term. Do not anticipate any significant updates this evening.

***From Previous Discussion***

Solid marine layer stratus field continues south of Pt Conception
today, though bases are higher so dense fog isn`t an issue near
the coast anymore. However, as the clouds push inland tonight
there`s a good chance that areas of dense fog will develop in some
of the coastal valleys of LA/Ventura Counties.

Otherwise, a pretty quiet weekend and Monday weather-wise. There
will be another mini surge of northerly winds later tonight into
Sunday morning across southern Santa Barbara County and the I5
corridor. Mostly below advisory levels though there could be some
isolated gusts to around 40 mph. Temperatures cooled several
degrees inland today with the marine layer push and expect a few
more degrees of cooling Sunday. Low clouds will continue to sit
near the coast from Santa Barbara south each afternoon with
limited clearing.

The next system still on track for an arrival on Tuesday. NBM pops
were surprisingly low for SLO County given the virtual unanimous
model/ensemble agreement that at least some rain will fall and
those numbers were raised to more realistic values. In any event,
this will be minor system with very minimal impacts, if any.
Ensembles have shifted a little drier but still more or less in
the half inch territory for coastal SLO County, and tapering to
around a tenth for srn SB County and basically zero to maybe a
hundredth or two in Ventura/LA Counties. The added cloud cover
will make Tuesday the coolest in this 7 day stretch with highs
mostly in the 60s at lower elevations.

.LONG TERM (WED-SAT)...06/155 PM.

After the Tuesday system high pressure will return and last at
least through early the following week. Models have been
consistent showing a developing north to northeast flow pattern
Wed-Fri. There`s still some uncertainty whether this will be more
of a northerly event or northeasterly but ensemble wind speed
forecasts for the Santa Clarita Valley continue to hover in the
low 40s with several solutions in the 50s. And likely strongest
Thursday though not too much of a drop off on Friday. This would
suggest more of a traditional Santa Ana pattern and we`ll likely
need some wind advisories for LA/Ventura Counties. And given the
strong ridge in place with H5 heights close to 590 dam this looks
to be a very warm and dry event. Local temperature guidance based
on many years of offshore wind events strongly suggest coastal and
valley highs in the upper 80s to lower 90s. And given what
happened with the last couple of events (ie. CMA mid to high 90s)
would not be surprised if they end up being a little higher than
that. While the NBM has slowly crept up temperatures the last
couple days they are still far below what the pattern and previous
events would suggest and have gone ahead and bumped up coastal
highs 4-8 degrees above NBM.

Strongest winds and highest temperatures will be Thu/Fri. Still
quite warm Saturday though gradients definitely trending onshore
by then. Coastal areas should see some cooling but farther inland,
especially mountains and far interior areas will continue to warm
up through next weekend.

&&

.AVIATION...06/2211Z.

At 2200Z, the marine inversion at KLAX was based at 1300 feet.
The top of the inversion was 2600 feet with a temperature of
19 degrees Celsius.

Overall, moderate to high confidence in 00Z TAF package. North of
Point Conception, high confidence in CAVU conditions. For coastal
and valley sites south of Point Conception, high confidence in
return of IFR/MVFR conditions, but only moderate confidence in
timing and flight category changes.

KLAX...Overall, moderate confidence in 00Z TAF. High confidence in
low MVFR/IFR conditions through Sunday morning, but only moderate
confidence in timing of flight category changes. No significant
easterly wind component is expected.

KBUR...Overall, moderate confidence in 00Z TAF. High confidence in
return of IFR conditions (with a 30% chance of LIFR conditions)
overnight, but only moderate confidence in timing (could be +/- 2
hours of current 06Z forecast).

&&

.MARINE...06/727 PM.

High confidence in Small Craft Advisory (SCA) level winds across
the outer waters through Sunday evening, with a 40% chance of
them lasting through late Sunday night. There is a chance that
gusty winds may spread into the western portion of the Santa
Barbara Channel each afternoon and evening. Hazardous seas over 10
feet could return by Sunday.

From late Monday night through Tuesday a weak cold front will move
through the waters. There may be some briefly gusty S winds along
and ahead of the front mainly across the northern waters. On
Wednesday, good confidence in widespread gusty N to NW winds
across most of the waters.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 3 AM PST Monday for
      zones 670-673-676. (See LAXMWWLOX).

&&

.HAZARD POTENTIAL OUTLOOK (TUE-SAT).

Gusty north to northeast winds expected late Wednesday into Friday
morning.

&&

$$

PUBLIC...MW/Thompson
AVIATION...RAT
MARINE...Sweet/Stewart/Sirard
SYNOPSIS...MW

weather.gov/losangeles



Area Forecast Discussion

National Weather Service Memphis TN

 833 PM CDT Sat Nov 6 2021

.UPDATE...
Not much change in the forecast this evening. Clearing skies could
lead to some radiational fog across the area. Patchy fog
especially near the rivers will be possible. Sunday looks to be
sunny with highs in the 60s.

&&

.PREV DISCUSSION... /issued 311 PM CDT Sat Nov 6 2021/

DISCUSSION...

Rinse and repeat of yesterday. A beautiful fall day. Temperatures
are in the upper 50s and low 60s with a nice breeze. Latest
satellite imagery shows clouds over north Mississippi and west
Tennessee. Clouds should clear out through this evening. With a
clear sky overnight, coupled with minimal wind, patchy dense fog is
possible. Temperatures overnight are expected to be in the mid to
upper 30s.

A surface high is sitting over the region, while an upper level
ridge is continuing to build in from Mexico. An upper level low will
push east off the Florida coast. Flow aloft shifts more north-
northwestward. With the surface high, upper level ridging and plenty
of sunshine temperatures are expected to warm into the upper 60s to
low 70s by Monday. Overnight temperatures are expected to flow suit
and increase into the low to mid 40s.

The aforementioned surface high shifts to our east and a shortwave
trough will rotate through the Lower Great Lakes. A dry cold front
looks to stall to our north. With lack of moisture no rain is
expected at this time. In the meantime, another shortwave will move
southeast across the Rockies and into the Plains on Wednesday. A
cold front should arrive Thursday afternoon into the evening. The
cold fronts pushes through the region by Saturday afternoon. Post
frontal passage, daytime temperatures will cool back down into
the low 50s with overnight temperatures in the low to mid 30s.

SMW

AVIATION...
18Z TAFs

Shallow cumulus field developed at midmorning, mainly east of the
MS River. The cumulus was likely rooted in a shallow elevated
moist layer, above the morning boundary layer inversion. GOES
visible imagery indicated a slight cyclonic curvature to the cu
field near MEM late this morning, near the westward extent of the
cu field, perhaps indicative of weak convergence and late morning MVFR
ceiling potential. MEM aircraft soundings verified the 12Z MEM
NAM Bufr sounding, showing a steep thermal inversion above FL035
- capping the vertical extent of the cumulus. HREF depicts the
cumulus mixing out during the early/mid afternoon.

Overnight fog potential is likely of greater concern. NAM Bufr
soundings depicted very steep saturated boundary layer, even at
MEM. Given the fog this morning, minimal wind today and clearing
skies, the setup appears conducive for late night fog development.

PWB

&&


.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&

$$