Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/13/24
Area Forecast Discussion
National Weather Service Quad Cities IA IL
539 PM CST Tue Nov 12 2024
.KEY MESSAGES...
- Rain expected for Wednesday PM into Thursday morning where
totals will mostly range between 0.1 and 0.3" with areas in
northwestern Illinois seeing the higher amounts.
- Dry conditions and warmer temperatures (10 to 15 F above
normal) with highs in the mid to upper 50s for the end of the
week.
- Weather pattern turns more active for early next week but
uncertainty for the timing of precipitation.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 221 PM CST Tue Nov 12 2024
Low level clouds will continue this afternoon as moisture noted at
900hPa in RAP soundings continues to move north on the backside of
high pressure to the northeast. Model guidance has struggled with
this weather element throughout the day so there is some uncertainty
in when clearing will occur. Given the more cumuliform nature,
thinking we will see clearing as daytime heating ends and the
moisture continues northward. This thinking is supported by a west
to east clearing trend on current satellite imagery. However, there
is indication in RAP soundings that low level moisture will remain
overnight which would likely result in low level clouds overnight.
Higher forecast confidence as we head into Wednesday as a 500hPa
trough and low pressure currently seen across the Intermountain West
in water vapor imagery moves eastward and deepens in the Great
Plains. A slowing trend of these features continues to be noted in
the ensemble guidance with the 12.12z LREF members indicating
probabilities greater than a trace increasing to 30-60% after 12pm
CST. Low rainfall amounts continue to look likely, with higher
amounts missing much of the area to the west and northeast as higher
dewpoints and stronger moisture transport occur in these areas. 0.1-
0.3 inches of total accumulations are expected across the area
throughout the event with probabilities of higher amounts dropping
off quickly. The higher totals are expected towards north central
Illinois. Rain will end west to east Wednesday night.
&&
.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
Issued at 221 PM CST Tue Nov 12 2024
Thursday - Saturday: Dry Conditions, Above Normal Temperatures
As the storm system exits the region, shortwave ridging will occur
in its wake. During this period dry conditions are expected.
Temperatures will also be on the rise heading into the weekend where
highs are forecasted to be 10 to 15F above normal. This translates
to highs in the mid to upper 50s with some locations approaching 60F.
Sunday - Tuesday: Next System Moves In, Rain Chances Return
At the tail end of the weekend a shortwave trough moves into the
Upper Midwest. Most of the moisture associated with this will be
situated in southern Canada, however just ahead of a cold front
there may be a small chance at seeing some showers (10 to 15%)
across the area Sunday. Other than this brief stint of potential
rain, the main focus turns to a trough that will be over the western
CONUS. This trough is forecasted to push into the central US early
next week and bring increased chances at rain. There are some
uncertainties with how strong this trough will be and exact path it
takes. Depending on the path, will determine how much rain the area
will receive. The GEFS members show the potential for more rain with
the path of the low going more towards the Upper Midwest while the
ECMWF members don`t have as much in the way of rain due to the path
being further west into the northern Plains. Even with these
discrepancies, the overall precipitation chance is currently between
40 and 55%.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 525 PM CST Tue Nov 12 2024
Quiet weather is expected through the overnight into Wednesday
morning with prevailing VFR and dry conditions. An area of low
pressure tracking from the Central Plains into Iowa and Missouri
will bring a chance for showers toward the end of the period,
along with MVFR ceilings. Held off on mentioning rain in the
TAFs with this update due to low confidence on how quickly the
lower atmosphere will saturate.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...None.
MO...None.
&&
$$
SHORT TERM...Falkinham
LONG TERM...Cecava
AVIATION...Uttech
Area Forecast Discussion
National Weather Service Green Bay WI
601 PM CST Tue Nov 12 2024
Updated aviation portion for 00Z TAF issuance
.KEY MESSAGES...
- Low pressure will bring rain to the region on Wednesday night
and Thursday. Probability of rain is highest over eastern
Wisconsin where there is a 50-70 percent chance of greater than
a quarter of an inch.
- High temperatures will range from 5 to 10 degrees above normal
through early next week.
&&
.DISCUSSION...
Issued at 225 PM CST Tue Nov 12 2024
Short Term...Tonight and Wednesday
The latest RAP analysis and satellite/radar imagery show high
pressure centered over the northern Great Lakes to northeast
Ontario. Unstable conditions in the boundary layer combined with
easterly flow has led to widespread strato-cu across the region.
The clouds have partially mixed out and think this trend will
continue through the rest of the afternoon. More clouds are
building over southeast WI shoreline and southwest Wisconsin,
which should slowly lift north through the rest of the day.
Looking upstream, the next storm system is moving east across the
central Rockies. Focus in this forecast revolve around cloud
trends and rain chances on Wednesday afternoon.
Tonight...As boundary layer winds veer to the southeast or south
and a sharp inversion remains in place, expected clouds to get
recycled north as unstable conditions will remain over southern
Lake Michigan. Therefore expect skies to become partly to mostly
cloudy late tonight after a period of clearing late this afternoon
into early this evening. Due to breezy southeast winds and cloud
cover at times, increased min temps for some areas.
Wednesday...A brief period of clearing could occur on Wednesday
morning as clouds depart to the northeast and/or become closer to
Lake Michigan. But then mid and high clouds will be on the
increase ahead of the next storm system. Models have trended
slower with the arrival of the light rain, and most hold it off
until Wednesday evening. Have therefore slowed precip chances
down. High temps will range from the mid 40s to low 50s.
Long Term...Wednesday Night Through Tuesday
Focus of this forecast is centered around rain chances during two
periods, Wednesday night into Thursday and also late in the weekend.
Otherwise, like the previous forecaster noted, only minor weather
impacts are expected over the next week.
Precipitation chances: Low pressure will be moving east across the
southern Great Lakes during the Wednesday night through Thursday
time frame. A narrow warm conveyor belt will be surging north ahead
of the low and across eastern Wisconsin by late Wednesday evening,
thereby increasing precipitable water values upwards of 200% of
normal. Precip chances and percent chances of greater than a quarter
inch of rain has steadily increased over the past 24-48 hours over
northeast WI, and will continue the trend in this forecast. No
signs of elevated instability, but south winds will continue to be
breezy into the evening, particularly along the lakeshore. The
showery activity should diminish across most areas (except for the
Door Peninsula) on Thursday afternoon. Clouds may take until Friday
before departing over far northeast WI.
A dynamic low pressure system remains forecast to track north of the
region on Saturday night into Sunday. This low will push a cold
front across Wisconsin on Sunday. While precipitable water values
will rise to 180% of normal ahead of the boundary, humidity profiles
reveal disjointed moisture through the column (lack of deep
saturation). As a result, precip chances will remain low. But the
system will likely generate breezy south winds ahead of the front,
and northwest winds behind the front.
Temperatures: High temps will generally remain above normal for the
next week (normal high at Green Bay is in the middle 40s). Temps
will undergo a slow warming trend into Sunday, then fall back
several degrees on next Monday.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 601 PM CST Tue Nov 12 2024
Generally looking at VFR conditions through the TAF period, with a
focus on winds and potential for low clouds this evening and
tonight.
Winds...Winds will be steady from the southeast overnight, but
gusts should be minimal. LLWS will develop in central and north-
central Wisconsin late this evening and last overnight (approx 06Z
to 12Z). Southeast winds will gusts up to 20 knots area wide on
Wednesday.
Clouds...Skies were mainly clear at TAF issuance, but watching a
batch of low clouds coming off of Lake Michigan. As of 00Z, KMTW
was the only TAF site seeing FEW clouds at 2kft. Mixed guidance
on whether this area of low clouds will expand and to what degree.
Opted for TEMPO groups in east-central WI to account for potential
periods of MVFR cigs, confidence in exact coverage and timing is
low.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION.....MPC/MPC
AVIATION.......KLJ
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
933 PM CST Tue Nov 12 2024
.KEY MESSAGES...
- Rain showers are likely (70-90%) Wednesday afternoon/evening along
with a few rumbles of thunder.
- Mostly dry weather with near seasonal temperatures are
forecast Thursday through early this weekend.
&&
.UPDATE...
Issued at 933 PM CST Tue Nov 12 2024
High cirrus clouds blanket the CWA this evening and will remain
that way through the night. As clouds get thicker and lower, this
will slow the temps from falling much further. Overnight lows in
the upper 30s to around 40 still looks like a good forecast. Quick
look at new model runs, current forecast of precip staring in the
southeast late morning and then continuing to spread north and
northwest during the afternoon still looks good. Overall, forecast
looks good, but will make some minor changes to the sky cover
grids to better align with amount of cloud cover out there. Update
will be out shortly.
Auten
&&
.DISCUSSION...
Issued at 225 PM CST Tue Nov 12 2024
(Through Wednesday Night)
Strong high pressure centered over the Great Lakes continues to help
provide easterly surface winds and dry weather across central
Illinois. Low-level stratus/stratocumulus has been very stubborn to
lift/scatter out today, in large part due to the lower sun angle of
mid November. The RAP has been handling this area of cloud cover
well, and used it to up clouds through the evening across central
and northeastern portions of the forecast area. Not sure if it will
hold on through the whole night though, as some weak dry advection
is forecast to occur. However, mid/upper level cloudiness will begin
to increase from the southwest ahead of an approaching trough. These
clouds will gradually lower through the morning/afternoon hours.
Chances of rain showers will increase first in parts of
eastern/southeast Illinois from late morning into the afternoon
hours as strong low-level moisture convergence advects in from the
mid south. Another area of widespread showers, along with a few
rumbles of thunder, should be moving west to east across the
Mississippi River late afternoon and move through central Illinois
through the late evening hours. This area of rain will be associated
with a prefrontal trough axis with ascent downstream of the midlevel
shortwave trough.
By the time the rain moves out Wednesday night, most area are
expected to see at least a tenth of an inch of rain, but
southeastern portions of the forecast area should see the most. This
is where amounts above 0.50" are most likely (30-50%).
Temperature wise, mild conditions are forecast both tonight and
Wednesday night due to cloud cover and winds staying up each night,
preventing any radiational cooling. Lows both nights are expected to
be mainly in the 40s, or about 5-10 degrees above normal for mid
November. Highs on Wednesday are forecast to stay in the mid to
upper 50s, near to slightly above normal for the date.
(Thursday - Saturday Night)
Thursday will be a chilly, brisk day with plenty of low stratus.
Model RH plots show >90% saturation across the area between 875 and
950 hPa. Given the pattern (broad, cyclonic flow aloft), this makes
sense. Hard to see much if any sunshine given this setup, and these
clouds combined with weak low-level cold advection, temperatures
will not budge much from morning lows. Look for highs in the low to
mid 50s for Thursday afternoon. However, given the cloud cover and
brisk northwest winds, it will look and feel quite a bit chillier.
Dry weather with gradually moderating temperatures is forecast to
end the work week and start off the weekend as a mid/upper level
ridge moves eastward across the Mississippi Valley.
(Sunday - Next Tuesday)
A cold front is expected to move through the area sometime Sunday as
a surface low moves toward Hudson Bay. Surface convergence along
this front is weak, as is moisture return and the stronger mid/upper
level forcing for ascent is in southeast Canada. This means rain
chances are not too high (20-30%), and any rain that does fall
during this time period should be very light.
Attention then turns to how a midlevel shortwave trough evolves in
the desert southwest for early next week. Clusters of the 500-hPa
height pattern though show a lot of variability with the timing of
this feature. This is not uncommon for closed lows in the desert
southwest in the cool season. Generally speaking, slower solutions
tend to be more correct, though there are signs of a notable
"kicker" shortwave upstream crashing the Pacific Northwest coast so
there does not appear to be too much room to delay its ejection. The
bottom line is it appears likely that rain chances will ramp up late
Monday into next Tuesday associated with this system, but the finer
points (timing, amounts, etc.) will need to be refined in the coming
days.
&&
.AVIATION... (For the 00z TAFs through 00z Wednesday Evening)
Issued at 527 PM CST Tue Nov 12 2024
VFR conditions will prevail at all sites through the night and
into tomorrow morning. Scattered high cirrus is spreading over
central IL this evening, with these sky conditions continuing
through the night. High cirrus clouds will become more broken
tomorrow morning with cig heights dropping to between 15kft and
20kft. Showers and lower clouds should also advect into the region
tomorrow afternoon with SPI, DEC, & CMI lowering to 2kft with
light showers at 20z, followed by PIA and BMI around 21z. Winds
will be easterly tonight and then become southeasterly tomorrow
with daytime speeds around 12kts.
Auten
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Memphis TN
521 PM CST Tue Nov 12 2024
...New AVIATION...
.SYNOPSIS...
Issued at 215 PM CST Tue Nov 12 2024
Showers and thunderstorms will lift north along the Mississippi
River late tonight and develop eastward through the remainder of
the Midsouth on Wednesday. Rain should lift out of West Tennessee
and northeast Mississippi by late Wednesday evening. Fair and
seasonal weather will follow for Thursday, and persist through the
weekend.
&&
.DISCUSSION...
(This evening through next Monday)
Issued at 215 PM CST Tue Nov 12 2024
Midday GOES water vapor imagery showed progressive upper level
longwave trough over the central Rockies. This feature will lift
to the Great Plains by Wednesday morning, with diffluent
downstream flow overspreading the lower MS River Valley. A 925mb
warm front will lift into north MS prior to 12Z Wednesday, serving
as focus for showers and thunderstorms. 12Z HRRR progs MUCAPE as
high as 500 J/kg, rooted around 925mb. 40-50kt 925mb winds will
provide moisture influx during the day, with PWAT reaching as high
as 1.8 inches east of the MS River Wednesday afternoon. By
Wednesday evening, rain should lift east of the Midsouth, as the
slightly negative-tilted midlevel trough axis rotates through.
The upper level pattern will remain progressive through the
weekend. The Midsouth will experience fair and seasonal weather
under ridging aloft. The ridge axis will lift east of the Midsouth
on Monday, as a negative-tilt upper low ejects from the southern
plains into the upper Midwest. A stronger southern branch trough
will soon follow, digging into the southern plains by next Tuesday.
This system may phase with a northern branch low, resulting in a
large cut-off upper low centered over the mid-MS River Valley by
the middle of next week. Much time remains for such complex
pattern to develop, and the global models have yet to settle on a
consensus. But there at least appears to be a better than even
chance of cooler than normal temperatures for the Thanksgiving
holiday.
PWB
&&
.AVIATION...
(00Z TAFS)
Issued at 512 PM CST Tue Nov 12 2024
VFR conditions will continue through the evening hours. Showers
and scattered thunderstorms will move into the region from south
to north by early Wednesday morning and continuing through the
end of the forecast period. Ceilings will gradually lower from
MVFR Wednesday morning to LIFR by late afternoon. Winds will be
mainly from the northeast around 5 knots tonight. Winds will be
southeast on Wednesday around 10 knots with higher gusts in the
afternoon. Some low level wind shear on Wednesday across portions
of west Tennessee.
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
PUBLIC FORECAST...PWB
AVIATION...ARS
Area Forecast Discussion
National Weather Service Marquette MI
626 PM EST Tue Nov 12 2024
.KEY MESSAGES...
- Mostly dry weather until the next system arrives late Wednesday
through Thursday, bringing up to a quarter inch of rain for the
south-central and Lake Michigan communities.
- Southerly winds ahead of the cold front will gust up to 30 mph
Wednesday.
- Another quiet period of weather to follow until next round of rain
arrives Sunday.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 340 PM EST Tue Nov 12 2024
Dry conditions will prevail through tonight as Upper Michigan
remains under the influence of high pressure. RAP analysis/water
vapor imagery this afternoon show an extensive area under a 1031 mb
surface high covering much of the central and eastern portions of
the CONUS. Meanwhile, the next shortwave/frontal system is situated
over the Rockies, and that will be the main focus early in the
extended period.
Tonight, the main thing to note will be the tightening pressure
gradient between the aforementioned high pressure and Rockies
systems. An uptick in winds/mixing will help to mitigate the effects
of radiational cooling. Southerly winds could gust up to 15 to 20
mph overnight, keeping lows in the upper 20s/low 30s despite the
clear skies. As always, warmer temperatures will be confined to the
lakeshores. Currently, ground-based obs are generally reporting
widespread 40s across Upper Michigan.
&&
.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
Issued at 305 PM EST Tue Nov 12 2024
A progressive pattern aloft over the CONUS is present as at 12Z
Wednesday at 500mb, troughs will be just off the coast of the
Northeast, over the Great Plains, and approaching the Pacific
Northwest with ridging over the eastern CONUS and the Rockies. The
pattern slows down a bit later in the week as a minor Rex block sets
up downstream with strong ridging over coastal Quebec and a deep
cutoff low southeast of Nova Scotia. Upstream troughing arrives over
the Rockies on Saturday which should send low pressure into the
Upper Great Lakes later in the weekend, but ensemble spread is high
on the development of the Atlantic cutoff low, which has
ramifications on the upstream ridging and troughing.
12Z Wednesday, the trough to the west will support deepening surface
low pressure over the Central Plains, with a warm front extending
eastward lifting towards the Lower Midwest and an occluded front
analyzed northward to the Canadian Prairies. Cloud cover begins to
increase from west to east after 12Z Wednesday as the surface low
begins to lift NE-ward and the occluded front slowly approaches the
Great Lakes. However, rain in the southern and western UP holds off
until around 00Z Thursday with areas to the east looking to stay dry
through the night. Rain showers finally spread into the central and
eastern UP around 12Z Thursday as the surface low tracks through
the Lower Midwest and the frontal boundary sweeps through the UP.
With mean PWATs only increasing to around 0.75 inches, not a ton of
water in the atmosphere will be available for precipitation, and the
mean QPF totals around 0.1 to 0.2 inch for much of the UP, though
the south-central and Lake Michigan shoreline communities are more
likely (40-60% chance) to see a quarter inch or more of
precipitation. The compressed pressure gradient between the arriving
front and the strong surface high well to the east will allow for
wind gusts to climb again for Wednesday, though not nearly to the
extent of Monday with forecast wind gusts over land of 20-30 mph.
Lingering chances (15-30%) of rain linger overnight Thursday with
some north/northeast upsloping. Ridging aloft will help support a
1020s mb high pressure just south of the Midwest that should keep
most of the UP dry into the weekend. Then, attention turns upstream
to the development of a Colorado Low which ensemble guidance has
tightened up the track of somewhat in the past 24 hours. The low is
expected to deepen to 1000mb just NE of Colorado 12Z Saturday,
moving towards the Manitoba/Ontario border by 12Z Sunday.
Precipitation with this system will fall as rain, though the details
on timing and intensity of rainfall is uncertain as spread is high
on downstream conditions. Indications are for a brief window for dry
weather early next week with ridging over the area ahead of another
deep low ejecting out of the Plains, but ensemble spread regarding
track is high this far out. Otherwise, expect temperatures to remain
above average throughout the extended period with lows generally in
the 30s and highs in the 40s to lower 50s.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 626 PM EST Tue Nov 12 2024
VFR conditions will prevail at all terminals this TAF period,
although increasing low level cloud cover across central Upper
Michigan may support some MVFR ceilings at times overnight into
Wednesday morning at KSAW. Strong low level jet will support gusty
southerly winds and some low level wind shear mainly at KIWD/KCMX
overnight. Gusty southerly winds will continue through the day on
Wednesday.
&&
.MARINE...
Issued at 305 PM EST Tue Nov 12 2024
Southerly winds will be on the increase this evening with high
pressure sliding east of the Great Lakes and troughing over the
Plains. Expect gusts to 20-25kts this evening into tonight,
increasing to 25-30kts for Wednesday. A few gale force gusts are
possible in the east Wednesday afternoon and evening, but chances
have fallen over the last 24 hours with probabilities of gales over
eastern Lake Superior now isolated patches of 20-30% per ensemble
guidance. Winds slowly fall back below 20kts behind a cold front
Wednesday evening and night. Winds will then remain under 20 kt
before increasing late Saturday into Sunday ahead of another low
pressure system.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...TDUD
LONG TERM...LC
AVIATION...JTP
MARINE...LC
Area Forecast Discussion UPDATED
National Weather Service Portland OR
801 PM PST Tue Nov 12 2024
...UPDATED for evening aviation weather.
.SYNOPSIS...A week of active weather ahead with a combination of
wind, rain, snow, and thunderstorms. Strong frontal system with
a coast jet will promote strong winds tonight into Wednesday
morning with the highest speeds along the coast. Wind Advisory
and High Wind Warnings in effect through Wednesday morning.
Heavy rain expected which, when combined with the fallen leaves
and clogged drains could lead to localized urban flooding. In
Wednesday also will bring increased chances for thunderstorms
with the chance for waterspouts near the coast.
&&
.SHORT TERM...Now through Wednesday Night...A strong area of low
pressure drops down from the Gulf of Alaska which will bring a
variety of weather based concerns to the region. The first main
concern is wind late tonight into Wednesday morning. This
front`s pressure gradient is strong and is associated with a
multi-layered jet. Looking at forecast model soundings, winds
around 4000 ft AGL are around 50+ mph. These winds will likely
mix down along the coast with the energy of the system. High
Wind Warning is in effect for the coastal areas with gusts up to
60 mph expected. The hi-resolution guidance has "backed off" a
bit in regards to the peak wind speeds, but the 90th percentile
of the HREF still is producing 65+ mph winds along the Central
Oregon Coast. Winds will also be elevated along the Cascades and
the Willamette Valley. While the valley will not see nearly as
strong of winds due to it`s proximity to the jet, gusts are
still high enough to near 45 mph. The main impact is going to be
the potential for downed trees due to them being water soaked
and covered in leaves still. While winds will decrease in the
afternoon on Wednesday, conditions will remain breezy.
The next sensible weather feature is rain. While river flooding
is highly unlikely (<5% chance for any given river to reach
minor flood stage according to the latest HEFS guidance), there
is a higher risk for urban flooding in low-lying areas with poor
drainage. Given many storm drains are currently clogged up with
leaves, hourly rain rates around 0.2 in/hr or higher will be
enough to cause some issues in flood- prone areas. The UWWRF and
the HRRR both show hourly rain rates peaking between 0.2-0.4
in/hr around 0500 Wednesday. These higher rain rates will be
topography driven and whether or not thunderstorms form. The
best chance for urban flooding will occur Tuesday night through
Wednesday. If you encounter a flooded road when driving, be
sure to turn around if possible as it is impossible to tell
exactly how deep the water may be. Be sure you have a way to
receive NWS advisories and warnings and remember - turn around,
don`t drown.
Now onto the thunderstorm potential. The Storm Prediction Center
has put the coastal areas under a "marginal risk" of
thunderstorms. Based on the forecast soundings, will have skinny
but ample CAPE, and speed and directional wind shear. Have
increased chances of lightning to 15-30% with the highest
probability along the Coast. While initially the morning looked
to be the time frame of the highest potential, the conditions
have extended through the afternoon. These storms will bring
locally higher rainfall amounts, gusty winds, and the potential
for rotation.
There are also concerns for high surf conditions and minor tidal
overflow flooding at the coast with the upcoming Perigean Spring
tides. For more details on these hazards, please refer to the "Beach
Hazards" section below. -Muessle/TK
.LONG TERM...Thursday through Tuesday...The long term forecast
is highlighted by a cool and showery weather pattern typical of
mid-November. WPC`s cluster analysis for 500 mb heights and
anomalies suggests excellent agreement between the GEFS/EPS/CMC,
showing an upper level trough over the coastal waters late
Thursday shifting inland over the western CONUS Friday. At 500
mb, there is a weak ridge attempting to build in but it is
unsupported at the surface. Even with this being the case,
northerly flow will dominate and cannot rule out clearing skies
though which will support much cooler overnight lows. The
probability for low temperatures near freezing overnight Friday
into Saturday morning have seen little change. For rural areas
of the inland valleys, there is around a 50% chance of below
freezing temperatures. Near Eugene is around 70-80%. Probabilities
are around 60-700% for the valleys of the Cascade Foothills
around Sweet Home, Creswell and Molalla. The greater Portland-
Vancouver metro area still has less than a 5% chance for below
freezing temperatures.
This cooler and drier pattern will quickly come to an end as the
flow becomes zonal on Sunday with increasing onshore flow. This
onshore flow will send a Pacific frontal system inland bringing
more significant rain amounts late in the weekend. That being
said, expecting minimal impacts with this system as winds do not
look significant and ensemble guidance for QPF suggest rain
amounts will not be high enough for hydro concerns.
Weak ridging attempts to build in once again early next week but
will be difficult to overcome the pervasive troughing from this
last week. However, more and more model ensemble guidance is showing
a transition to strong offshore flow middle to late next week,
bringing the potential for gusty east winds along with dry weather.
Will need to watch how model guidance evolves over the coming days as
uncertainty is currently high. -Muessle/TK
&&
.AVIATION...No changes overall. Rain with VFR inland this evening,
with mix of MVFR and VFR along the coast. Satellite showing
developing low pressure off the south Oregon coast. As such, this
will likely slow the arrival of gusty south winds across the
northern TAF sites. Will adjust 06Z TAFs to show this, with east
winds likely to persist near PDX/TTD til front arrives (12Z to 14Z).
Expect CIGS to hold at lower VFR until after midnight, then lower to
MVFR overnight. Not much change through Wed am, but will see rain
changing to showers and a few thunderstorms after the front shifts
inland Wed am.
Main concern will be gusty south winds along the coast overnight,
and inland for a time later tonight into early Wed am. Generally,
surface winds gusting 50 to 60 kt along the coast, with 35 to 45 kt
inland. Winds will ease behind the front, around 12Z to 14Z on coast
and after 15Z inland.
PDX APPROACHES...Rain with lower to mid-range VFR until 08Z, with
east winds 10 to 15 kt. After 08Z, will see CIGS gradually lower
back to MVFR as rain increases. Surface winds remain easterly til
front arrives (around 13Z to 14Z), then will become gusty from
south. But, winds to west and south of the airport will be southerly
and gusty earlier. Expect turbulence, with modest east winds 40 to
50 kt at and above 2000 AGL from 10Z to 16Z Wed.
&&
.MARINE...Headed into this evening a strong frontal system slated
to push into the coastal waters with southerly winds quickly ramping
up and peaking overnight - high confidence in Storm Force (>48 knot)
gusts. A coastal jet is also likely going to set up tonight, with
winds just above the surface(500-1000 ft) pushing 70 knots. Should
these winds get mixed down towards the surface as the front passes,
it is possible (30-40% chance) for some gusts closer to 65 kt. Seas
are expected to become very steep and chaotic, likely 20 to 25 ft
again overnight as a fresh southerly swell also develops driven by
the aforementioned wind.
Behind the frontal boundary seas are expected to subside into the
mid to upper teens by Wed afternoon but winds gusts remain near 30-
35 knots into the early evening. It`s worth noting weather
conditions remain active through Wednesday with another round of
thunderstorms possible (20-40% chance) into Wed night, any of which
could produce erratic wind gusts, lightning, and even a few isolated
waterspouts.
Westerly winds will continue to ease through Thursday, while another
mid-period westerly swell moves into the coastal waters at 14 to 17
feet around 15 seconds. Once this swell passes the wave state
finally calms for the second half of Friday into Saturday with
significant wave heights dipping below 10 feet. However we`ll need
to watch another weather disturbance expected to arrive late Sunday
into Monday bringing another round of active weather.
-Schuldt/DH
&&
.BEACH HAZARDS...A High Surf Advisory remains in effect until 4pm
today (Tuesday) with westerly swells driving breakers up to 20 to 25
feet. This high surf will affect beaches, producing rip currents,
sneaker waves and beach erosion. Remain alert for exceptionally high
waves and stay a safe distance from the water`s edge.
A strong weather system on Wednesday will bring the possibility of
tidal overflow and minor coastal flooding during high tide Wednesday
morning into the mid afternoon hours, especially for the northwest
Oregon coast and southwest Washington coast where a Coastal Flood
Advisory is in effect. And while unrelated to the current series of
weather disturbance, the perigean spring tides, also known as king
tides, will begin Friday November 15, increasing high tides. Will
continue to monitor total tides along with the response of local
rivers along the coast this week.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...High Wind Warning until 6 AM PST Wednesday for ORZ101>103.
Coastal Flood Advisory from 7 AM to 1 PM PST Wed for ORZ101.
Wind Advisory until 6 AM PST Wednesday for ORZ108>111-114>118.
WA...High Wind Warning until 6 AM PST Wednesday for WAZ201.
Coastal Flood Advisory from 7 AM to 1 PM PST Wed for WAZ201.
Wind Advisory until 6 AM PST Wednesday for WAZ204>206.
PZ...Storm Warning until 7 AM PST Wednesday for PZZ210-251>253-
271>273.
Hazardous Seas Warning from 7 AM Wednesday to 4 AM PST Thursday
for PZZ210-251>253-271>273.
&&
$$
www.weather.gov/portland
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