Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 11/10/21
Area Forecast Discussion
National Weather Service Phoenix AZ
400 PM MST Tue Nov 9 2021
.UPDATE...
Updated Aviation
&&
.SYNOPSIS...
A quick-moving weak disturbance moving across the region today will
keep temperatures near normal through midweek. Temperatures then
warm back up to several degrees above normal by the end of the week
as strong high pressure builds along the U.S. west coast. Breezy
conditions are expected Thursday, especially near the Lower Colorado
River. No precipitation is in the forecast through at least the next
week.
&&
.DISCUSSION...
Satellite this afternoon shows a shortwave trough moving east across
the region with the trough axis already nearing the AZ-NM border.
Cirrus clouds are moving in from the northwest on the backside of
the shortwave, keeping skies partly cloudy. A 24-hr evolution of
aircraft soundings out of Phoenix shows slightly cooler temperatures
in the PBL and just above, resulting in the cooler surface
temperatures today. Phoenix ASOS is running about 5 degrees cooler
on average through 1 PM MST. Highs this afternoon are only expected
to top out in the low-80s across the lower deserts and remain in the
70s for many of the higher elevation locals in Gila county.
An area of fog, locally dense, did develop again this morning,
mainly between El Centro and Yuma, but this is expected to be the
last morning over the next week or so with fog. In the wake of the
shortwave trough, there will slightly stronger sundowner winds
pushing across Imperial County this evening with gusts up to 20-25
mph, as depicted by the HREF. These westerly winds will also push
drier air down to the surface, lowering dew points several degrees.
A trailing subtle cold front is also expected to push into the area
tonight around midnight. This front will mostly act to shift winds
more northerly. NBM and global models show the northerly gradient
winds will become breezy to locally windy Wednesday through Friday.
Ensembles have the strongest gradient winds lining up down the Lower
Colorado River area and have Thursday as the breeziest day with
speeds perhaps peaking as high as 30-35 mph or so. Strong winds
could also generate localized blowing dust. Winds in south-central
AZ are expected to be notably lighter, but still breezy, with gusts
to around 15-20 mph.
CPC clusters maintain great agreement in the development of a strong
ridge across the West Coast during the second half of the week.
There is slightly better consistency among the clusters in terms of
the amplitude of the ridge, as compared to yesterday, but it remains
the primary variance among models. Ensemble consensus also keeps the
ridge axis just to the west of the local area through at least the
end of the week and perhaps through the weekend before weakening and
transitioning eastward. This will somewhat limit the warming
potential heading into the end of the week, but a gradual warming is
still expected. Accordingly, western deserts will likely be the
warmest being closer to the ridge axis. NBM supports highs warming
up to near 90 degrees in the western lower deserts as early as
Thursday or Friday, while the south-central AZ lower deserts warm
back into the mid to upper 80s. Morning lows will mostly remain
unchanged around 55-60 degrees each day. Lastly, with the strong
ridge during the second half of the week and no notable troughs
through this weekend, NBM PoPs are zero through the next 7 days at
least.
&&
.AVIATION...Updated at 2300Z
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Other than a period of thick high cirrus this evening, no major
weather impacts will exist through Wednesday evening. Trends and
timing of wind direction shifts will be nearly identical to the past
several days, though speeds in the afternoon after the westerly
switch will be somewhat stronger than the past couple days.
Southeast California/Southwest Arizona including KIPL and KBLH:
Only minimal weather impacts related to gusty winds are possible
through Wednesday evening with just a brief period of thicker high
cirrus decks. Wind directions will eventually favor a NW to N
direction Wednesday with some gusts up to 20 kt possible -
particularly at KBLH.
&&
.FIRE WEATHER...
Thursday through Monday:
Dry conditions and weak high pressure will persist across the
region through the period leading to above normal temperatures.
Winds will generally be light and favor diurnal patterns, but some
breezy winds are expected across the Lower CO River Valley Thursday
and to a lesser degree on Friday as well. Wind gusts may reach 20-
30 mph on those days. Min RH values will mostly fall into a 10-20%
range. Max RH values will be 35-50%.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
DISCUSSION...Benedict
AVIATION...18
FIRE WEATHER...Hodges
Area Forecast Discussion
National Weather Service Seattle WA
221 PM PST Tue Nov 9 2021
.SYNOPSIS...Strong onshore flow this afternoon will ease overnight.
Showers, thunderstorms, and blustery winds will continue into the
evening and heavy snow will fall in the mountains. Scattered
showers Wednesday morning should end in the afternoon as Western
Washington gets a brief break in the weather. Rising snow levels
and an atmospheric river will bring heavy rain to the mountains
later in the week with a chance of river flooding.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...With two of our forecasters
watching the radars this afternoon, it falls to me, forecaster 19
to write the entire AFD--which is a nicer task than radar ops for
sure. The showers, squalls and thunderstorms are mostly being
handled with special weather statements, special marine warnings,
and even a tornado warning today--although it does not look like
that storm produced more than a little hail and some wind over
around Silverdale--but storms have had some rotation at times and
it has been a busy day.
Showers and thunderstorms will continue into the evening--we had
a heavy shower and exciting wind gusts here at NOAA on Lake
Washington, but it wasn`t long before a bright rainbow replaced
the stormy weather. With plenty of gusty squalls on radar and
satellite still streaming in this afternoon, the gale warnings
over the waters will stay up into the evening. Heavy snow showers
will fall at times in the mountains--probably picking up through
the evening as the westerlies over the Cascades get stronger so
the winter storm warning continues into the evening there.
Scattered showers Wednesday morning ought to end by afternoon for
a brief break in the weather. A warm front will arrive Wednesday
night and Thursday followed by an atmospheric river weather
pattern Thursday night and Friday--a strong, moist, and rather
warm plume of moisture will be directed into Western Washington
for a period of heavy rain--especially in the mountains. 19
.LONG TERM /SATURDAY THROUGH TUESDAY/...The heavy rain will taper off
Friday night and Saturday looks like a break in rain. Another
warm front might arrive Saturday night and Sunday, followed by a
cold front around Monday afternoon or night. 19
&&
.AVIATION...Showers and a few thunderstorms were moving through
Western Washington this afternoon with blustery winds and areas of
MVFR cigs and vsby in the showers--although for a few minutes
conditions here at NOAA were certainly IFR as a heavy shower moved
through. Not a good day for small aircraft to be up. The
mountains are mostly obscured in heavy snow showers. The weather
will settle down overnight and the shower activity will taper off
through Wednesday morning with a break in the weather Wednesday
afternoon. 19
KSEA...A pretty decent band of showers moved over Seattle around 21z
and a few of the tops on radar were 20-25kft--and at 2130z there
were a handful of lightning strikes over the Kitsap Peninsula. It
will be worth watching the radar into the evening hours as more
of these bands of showers move thru the area. As I type this the
sun has come back out in Seattle, but the next band of showers is
queued up just to the west at 230pm.
&&
.MARINE...With showers and squalls moving through the area I will
keep the gale warnings up over the waters into the evening hours.
There have been a few thunderstorms this afternoon and that risk
will continue into the evening. There will be a break in the
weather on Wednesday and then a warm front will reach the area
Wednesday night and Thursday--but the main weather story into the
end of the week isn`t likely to be the winds but rather just the
heavy rain. 19
&&
.HYDROLOGY...The Skokomish river remains above flood stage
with a flood warning, but there will be a break as we get into
Wednesday ahead of the atmospheric river that sets up for the end of
the week. A hydrologic outlook was issued for most of Western
Washington for Thursday night through Saturday as snow levels rise
and heavy rain falls in the mountains. 19
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Winter Storm Warning until 10 PM PST this evening for Cascades
of Pierce and Lewis Counties-Cascades of Snohomish and King
Counties-Cascades of Whatcom and Skagit Counties-Olympics.
PZ...Small Craft Advisory until 10 PM PST Wednesday for Grays Harbor
Bar.
Gale Warning until 3 AM PST Wednesday for Coastal Waters From
Cape Flattery To James Island 10 To 60 Nm-Coastal Waters
From Cape Flattery To James Island Out 10 Nm-Coastal Waters
From James Island To Point Grenville 10 To 60 Nm-Coastal
Waters From James Island To Point Grenville Out 10 Nm-
Coastal Waters From Point Grenville To Cape Shoalwater 10
To 60 Nm-Coastal Waters From Point Grenville To Cape
Shoalwater Out 10 Nm.
Gale Warning until 9 PM PST this evening for Admiralty Inlet-
Central U.S. Waters Strait Of Juan De Fuca-East Entrance
U.S. Waters Strait Of Juan De Fuca-Northern Inland Waters
Including The San Juan Islands-Puget Sound and Hood Canal-
West Entrance U.S. Waters Strait Of Juan De Fuca.
&&
$$
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