Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/14/18
Area Forecast Discussion
National Weather Service Cleveland OH
1013 PM EST Tue Nov 13 2018
.SYNOPSIS...
High pressure will build in from the west over the lower Great
Lakes by Wednesday. The high will move northeast to Maine by
Thursday. Low pressure will move northeast to the Ohio Valley by
Thursday and then shift to the East Coast by Thursday night.
High pressure will build up the Appalachian Mountains Saturday
with a cold front moving east across the local area Saturday
night.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
Update...Will continue trend of decreasing snow showers off
lake erie across northwest pa although did lower pops to
likely/chance from categorical. Minor sky cover adjustments as
well but no big changes for overnight update.
Original...Satellite imagery and regional radars shows lake
enhanced and lake effect clouds and scattered snow showers this
afternoon. 850mb temps advecting in over the region are -10C to
-12C. These colder temperatures aloft are causing about 50 to
100 J/KG of MUCape and instability. Using area TWDRs and mosaic
imagery shows bands of light snow developing over the lake this
afternoon and impacting the primary Snowbelt region east of the
Cleveland area. We followed the guidance from the HRRR and
NAMnest closely with several bands expected to develop and
impact far northeastern Ohio into northwestern Pennsylvania. At
this time, we will mention the possibility of 1 to 2 inches
across NE Ohio and 2 to 4 inches with isolated higher amounts
across Crawford and Erie Counties in Pennsylvania. At this time,
we will not issue an advisory for the primary snowbelt areas.
But if more snow is anticipated this evening, a quick headline
may need to be issued.
Lake effect cloud cover will hold on for downwind of the lake
this evening and overnight with so eroding of the clouds during
the day on Wednesday. Coldest temperatures will be closer to
western and central Ohio tonight with readings down to near 20
degrees. Tomorrows highs will be mostly depending on the amount
of sunshine but mid 30s are expected across much of the area.
All lake effect snow showers will be done and fair skies late on
Wednesday.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
Little change in the short term forecast. Coastal low will
develop and track up the East Coast Thursday, lifting a trough
across the forecast area. Nice WAA pattern setting up. Expect
some light snow to develop from the south in the morning,
gradually changing to rain over entire area by late afternoon.
Potential for a brief period of sleet or freezing rain as precip
transition with overrunning. Bulk of the precip will have
exited the area by daybreak Friday as low tracks into New
England. Potential for some lake effect snow showers in the snow
belt on Friday.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
Below normal conditions continue through the long term
forecast. Models continue to differ on the timing of the next
cold front. The ECMWF moves the weak front through on Saturday
while the GFS holds off until late saturday night into Sunday.
With so much doubt in the timing will continue with low chance
pops Saturday into Sunday.
&&
.AVIATION /00Z Wednesday THROUGH Sunday/...
Expect slowly improving conditions through the night and into
Wednesday as high pressure and drier air move in from the west.
Will need to hang onto snow showers KERI for a few more hours
but do not expect visibility restrictions. Otherwise there
biggest threat for patchy MVFR CIGS at KMFD, KYNG and KCAK
mainly through the evening. Otherwise expect VFR.
OUTLOOK...Non-VFR possible Thursday night and Friday.
&&
.MARINE...
Updated...Winds a bit higher on the west end than earlier
anticipated so issued a small craft advisory. Winds will be
coming down through the early overnight period so will end at
4am.
Original...Small craft advisory will continue into tomorrow
with NW flow of 15 to 25 knots. Winds diminish from the west
tomorrow as the low tracks across Quebec, and high pressure
builds over the Lower Lakes. Winds shift to the S to SE tomorrow
night as the high moves east of the Lake. Another coastal low
develops and deepens to 29.40 inches off the Mid Atlantic Coast
by Friday morning, with a trough across the Lower Lakes. A small
craft advisory will be needed.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...Small Craft Advisory until 10 AM EST Wednesday for LEZ145>149.
Small Craft Advisory until 4 AM EST Wednesday for LEZ143-144.
&&
$$
SYNOPSIS...Griffin
NEAR TERM...Griffin/TK
SHORT TERM...DJB
LONG TERM...DJB
AVIATION...TK
MARINE...DJB/TK
Area Forecast Discussion
National Weather Service Cheyenne WY
157 PM MST Tue Nov 13 2018
.SHORT TERM...(This evening through Wednesday)
Issued at 146 PM MST Tue Nov 13 2018
No hazards or highlights in the short term with a nice warming
trend continuing today and moreso tomorrow. Temperatures remain
just below average today but will warm to near average and
slightly above average Wednesday with mostly sunny skies.
Latest water vapor imagery and RAP analysis indicates deep
northerly flow over WY and NE. Despite this wind direction, warm
air advection has taken place since yesterday as the colder
Canadian air has shifted farther east. This pattern switch is
allowing for surface temperatures to warm into the mid 40s for the
WY High Plains and even into the low 50s for the NE Panhandle.
Winds aloft will become more westerly overnight and Wednesday as a
shortwave ridge builds over the region. The subsident and
down-sloping wind component will further aid in the warming trend
as low 50s look probable for High Plains of WY with near 60F in
the NE Panhandle. These reading are about 3-8F degrees above
daily climate normals. The warm trend continues Thursday and
slightly into Friday before turning sharply colder late Friday and
into the weekend. See more details below on the high chance of
snow late Friday and into Saturday across the region.
.LONG TERM...(Thursday night through next Monday)
Issued at 315 AM MST Tue Nov 13 2018
Long range models in good agreement through next weekend with only
minor difference in timing with the next strong cold front
late Friday/Saturday. High temperatures on Friday will likely
occur earlier in the day with readings in the mid 40s to mid 50s
across the region. Models indicate a much colder airmass will
begin moving into Converse/Niobrara counties and likely across the
northern NE panhandle as early as noon Friday, with temperatures
rapidly lowering below freezing later in the afternoon.
Forecast looks on track for a potential Winter Weather event
beginning late Friday and continuing through Saturday evening
across most of the region. All models show a strong cold front
digging south along the mountains of Montana early on Friday as a
potent upper level disturbance moves southward west of the
Continental Divide. Models then show this disturbances digging
further west over time and slowing down, providing warm air
advection aloft. In addition, moderate frontogenesis and broad
upslope flow will be present along the mountains and across the
eastern plains. Models in very good agreement with the timing,
showing the onset of snowfall beginning Friday evening well north
of I-80, and by midnight Friday night/Saturday morning along the
I-80 corridor. Widespread light to moderate snow is possible
through Saturday morning, with snow generally becoming lighter
through the day Saturday. A bit too early to mention snow
accumulations, but historically these events tend to produce 2 to
5 inches of snow outside of the mountains. The only exception is
when the front and associated upper level trough become nearly
stationary, which leads to more snowfall. Thankfully, surface
winds do not appear to be too high late this week, which will
greatly limit drifting/blowing snow impacts. Continued to increase
POP up to 75 percent across much of the region through Saturday
with much colder temperatures during the day.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1018 AM MST Tue Nov 13 2018
VFR conditions expected across all terminal sites through the
period. Afternoon will have periods of gusty winds across the
majority of terminals before lessening during the evening and
overnight. Some high clouds possible through the forecast
timeframe.
&&
.FIRE WEATHER...
Issued at 146 PM MST Tue Nov 13 2018
Fire weather concerns remain minimal through the next several days as
fuel moisture is elevated and energy release components remain below
normal. Humidity values will drop into the 20 and 30 percentiles while
wind increases upwards of 20 to 25 mph at times during the afternoons
with the warm spell through Friday.
Much colder temperatures expected late Friday and over the weekend as
another round of widespread snow will occur across most fire weather
zones. Stay tuned for details on amounts towards late week.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...JSA
LONG TERM...TJT
AVIATION...WM
FIRE WEATHER...JSA
Area Forecast Discussion
National Weather Service Lincoln IL
808 PM CST Tue Nov 13 2018
.UPDATE...
Issued at 807 PM CST Tue Nov 13 2018
Latest surface map shows high pressure ridge from southwest
Wisconsin into Texas. Cirrus continues to stream across the
southeast third of the forecast area, which the RAP suggests will
continue through midnight before shifting southeast. With the high
becoming centered over the CWA by morning, the clear skies will
allow most areas to dip into the mid teens by morning, though
upper teens are more likely south of I-70.
Little change was needed to the gridded forecasts, aside from
updating the sky trends. The zone forecasts were updated to
correct a formatting error in the afternoon issuance.
&&
.SHORT TERM...(This evening through Wednesday)
ISSUED AT 303 PM CST Tue Nov 13 2018
Mostly clear skies expected through Wednesday as central IL sits
roughly in a col region between a deepening upper low moving from
the southern Plains into the lower Mississippi region and upper
troughing heading out of the Great Lakes into the north Atlantic.
Winds will be light and variable with weak surface pressure
gradients over the area, although a tendency toward a northeast
direction will develop during the day as surface low pressure starts
to lift northward into the TN region. The air mass remains far
colder than normal, and resulting lows should be in the teens
tonight, and mid to upper 30s Wednesday.
.LONG TERM...(Wednesday night through Tuesday)
ISSUED AT 303 PM CST Tue Nov 13 2018
The upper low developing in the southern Plains today looks to
follow a track just south of the Ohio River Thursday, spreading
precipitation into southeast Illinois starting Wednesday evening
south of I-70, continuing until Thursday evening east of I-57. A
chance for precipitation looks to spread about as far
northwestward as Jacksonville to Bloomington during the daytime
Thursday. A fairly persistent band associated with the deformation
zone wrapping around the north of this upper low could result in
heavy accumulations of snowfall, 4-7 inches, near and south of the
I-70 corridor, and a winter storm watch has been issued. Although
a wedge of warm air aloft looks to push northward ahead of the
low, current models keep any above freezing temperatures aloft
east of Illinois, therefore precipitation type looks to remain
completely snow until a loss of ice aloft potentially switches
precipitation to a brief period of freezing drizzle Thursday
evening.
Dry zonal flow aloft should keep dry conditions over central IL
Friday, then a cold front looks to push southeastward across
central IL Saturday, resulting in a chance for light rain and
snow. Ahead of the front southwesterly winds should bring highs up
to the 40s Friday, still below normal, followed by highs dropping
back into the 30s to low 40s for Saturday through Monday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 506 PM CST Tue Nov 13 2018
VFR conditions are expected to prevail, with mainly high clouds.
Only real area of concern is just south of KCMI, where some
patches of stratocumulus around 2500 feet currently exist. Hard to
tell with the high clouds moving overhead, but GOES-16 satellite
imagery suggests this is not really making any northward progress
at the current time. Will keep them VFR in the new TAF set as
well.
Northwest winds will gradually turn toward the north overnight and
east-northeast early Wednesday.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
Winter Storm Watch from Wednesday evening through Thursday
afternoon for ILZ066>068-071>073.
&&
$$
UPDATE...Geelhart
SHORT TERM...37
LONG TERM...37
AVIATION...Geelhart
Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
946 PM CST Tue Nov 13 2018
...WINTER WEATHER AND FREEZING TEMPERATURES EXPECTED OVERNIGHT AND
WEDNESDAY...
.UPDATE...
Updated for evening discussion.
&&
.DISCUSSION...
Water vapor imagery/RAP analysis showed the closed low spinning
over northeast Texas. This cold low has already pushed the 850mb
zero degree isotherm over our western zones Catahoula parish to
LeFlore county. Local radar are rather quiet. In fact, have
lowered pops in our southeast until after midnight when light rain
is still expected to redevelop. As the closed low draws closer
light precipitation is expected to develop including a wintry mix
as temperatures continue to fall. Latest surface observations
still have the freezing line north of Bolivar and Sunflower
counties. Morning lows still look on track with with our northwest
dropping below freezing well before sunrise. Wl continue the
Freeze Warning and Winter Weather Advisory for our northwest. /22/
Prior discussion below:
Tonight & Wednesday: Expect an active pattern of continued cold
conditions & winter weather potential through the period. Tonight
a deep upper cold core low will be diving down over the ArkLaTex
while split level flow & synoptic trough will be swinging through
the Great Lakes. At the surface, a strong surface ridge will be
building east- northeast across the mid-Mississippi Valley & into
the Great Lakes into tomorrow. Due to low-level cold air advection
& strong surface ridging (i.e. ~1025-1030mb MSLP across the
region), expect temperatures to slowly fall overnight into the
evening. Guidance is in good consensus that temperatures will fall
to near or below freezing in the ArkLaMiss Delta & near that
along & northwest of the Natchez Trace corridor. Went near a blend
with raw consensus guidance. Overall, previous thinking in the
HWO & graphics look good overall & no changes were needed. Kept
the current freeze warning area going after midnight tonight &
through around mid- morning Wednesday. Overall, only hindrance to
lows could be any winds & widespread clouds but favored leaning
towards raw guidance in this situation.
As this cold core low swings east-northeast into Wednesday morning
& through the day, expect increasing low-mid level moisture to
advect into the area. In addition, expect increasingly cool
profiles but there could be a low-level warm nose to deal with
into the afternoon, especially further east & southeast of the
Natchez Trace corridor. However in the ArkLaMiss Delta, there is
less of that & with continued cooling aloft & low-level wet bulb
temperatures near or less than freezing, a light wintry mix
changeover is possible in the morning after 3-4AM, especially in
the ArkLaMiss Delta. Further southeast towards the Natchez Trace
corridor, some areas could see a mix of light freezing drizzle or
light snow flurries but the best potential will remain in the
ArkLaMiss Delta from Morehouse Parish in Louisiana, Ashley &
Chicot Counties in Arkansas & along & northwest of a line
extending east-northeast towards Carroll & Grenada Counties. This
lines up well with neighbors & WPC on freezing rain probabilities
in the Delta. Right now this changeover could happen as early as
3-4AM with a majority after daybreak. There is some potential this
could extend further east & south, but some mid-level dry punch
could be a limiting factor. However, the CAM guidance, including
the ARW & NMM & op NAM are more bullish on QPF totals, but with
the op Euro backing off slightly, didn`t want to go as far
southeast as some of the more bullish guidance. HRRR seems to be
somewhat of a blend of the two with some developing in the Delta
with a minimum in between & more rain in east & southeast
Mississippi. In the I-20 corridor to Natchez Trace corridor, some
mix may be possible but moisture limitations keep out the mention
of more significant freezing rain. However, did leave at least
mention of snow flurries in. Regardless, as we struggle to warm
into the mid- upper 30s in the day, some of this will transition
back to rain as we warm up. However, this may be short lived as
somewhat colder thermal profiles continue to filter in into the
evening. One caveat is the Euro is slightly faster, which would
keep most of the developing precip slightly further north. Main
takeaway is even though accumulation will be light, in some areas,
especially the winter weather advisory area, a potential of a
wintry mix with up to a light glaze of ice & snow accumulations up
to one half inch, especially on elevated surfaces. However, this
is subject to change if the system moves in slower & thermal
profiles are colder & more saturated. Regardless, make
preparations now to account for some wintry mix potential
Wednesday. /DC/
Wednesday Night through early next week: Precipitation should be
coming to an end as we get into Wednesday night and the closed low
begins to eject northward out of the MidSouth while high pressure
at the surface begins to filter into the ArkLaMiss from the
southwest. However, some light flurries will be possible mainly
before midnight in the northeastern portions of our region as
precip comes to an end. Temperatures will fall into the 20s
areawide by Thursday morning as cold air continues to advect into
the region. A freeze watch has been issued for the entire region
and the freeze threat has been advertised in the HWO.
Drier air will continue to filter into the region on Thursday
resulting in decreasing cloud cover. The decrease in cloud cover
and lighter winds due to the surface high settling over the
northern Gulf Coast will help to aid the diurnal cooling effect
for Friday morning. Expect temps to fall into the 20s once again.
Temperatures will begin to warm as we get into the weekend and the
surface high moves east of the area. However, temps are still
expected to remain at least a few degrees below normal through the
period. Dry conditions will persist through the weekend. /JPM3/
&&
.AVIATION...
00Z TAF discussion:
MVFR flight categories were observed north of I-20 at 2330Z while
IFR flight categories continued along and south of I-20. IFR conds
are expected to prevail areawide by 09Z and continue through
Wednesday afternoon. An area of -RA and -DZ wl continue over the
se this evng then develop across the remainder of the area
Wednesday morning. Some flurries and light freezing rain wl be
possible across the nw from daybreak through noon before -RA
becomes predominant again. Wednesday evng additional flurries and
light freezing rain wl be possible across the ne, primarily GTR,
before the PCPN ends. /22/
&&
.PRELIMINARY POINT TEMPS/POPS...
Jackson 34 38 27 48 / 17 24 11 2
Meridian 37 41 28 48 / 39 49 22 4
Vicksburg 32 37 26 50 / 12 16 8 1
Hattiesburg 38 42 28 51 / 46 39 10 2
Natchez 33 38 27 51 / 10 11 6 1
Greenville 30 36 28 48 / 9 34 16 2
Greenwood 32 36 28 45 / 11 35 23 6
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...Freeze Watch from late Wednesday night through Thursday morning
for MSZ018-019-025>066-072>074.
Winter Weather Advisory from 3 AM Wednesday to midnight CST
Wednesday night for MSZ018-019-025>027-034.
Freeze Warning from 2 AM to 9 AM CST Wednesday for MSZ018-019-
025>028-034>036-040>042-047.
LA...Freeze Watch from late Wednesday night through Thursday morning
for LAZ007>009-015-016-023>026.
Winter Weather Advisory from 3 AM Wednesday to midnight CST
Wednesday night for LAZ007.
Freeze Warning from 2 AM to 9 AM CST Wednesday for LAZ007>009-
015-016-023>025.
AR...Freeze Watch from late Wednesday night through Thursday morning
for ARZ074-075.
Winter Weather Advisory from 3 AM Wednesday to midnight CST
Wednesday night for ARZ074-075.
Freeze Warning from 2 AM to 9 AM CST Wednesday for ARZ074-075.
&&
$$
JPM3/22/DC
Area Forecast Discussion
National Weather Service Nashville TN
753 PM CST Tue Nov 13 2018
.UPDATE...
FOR EVENING DISCUSSION.
&&
.DISCUSSION...
Upper low approaching the Arklatex region this evening.
Rainshowers covering much of the deep south, including Ga and the
southern two thirds of AL. Moisture is expected to lift northward
overnight and may reach into our far southeastern areas by 12z.
Hrrr concurs with this solution. BY 12z freezing heights are
sufficient for snowfall but 850 mb temps are rather warm. Still
though, with 850 mb wet bulbs close to 0C, will elect to continue
the slight chance of a rain and snow mix toward sunrise in the far
south. Temperatures should be near or just above freezing across
that far southern area around 12z.
Remainder of fcst looks to be in good shape. Weak Caa to continue
overnight so will see temps drop down a degree or two more. Update
will be sent in the next hour.
&&
.AVIATION...
00Z TAF DISCUSSION.
Cigs will continue to improve a bit overnight, with MVFR returning
for all terminals, however, IFR will make its return early
tomorrow afternoon as rain moves back into Middle TN. Look for IFR
to remain for awhile once it returns.
Winds will continue to be occasionally breezy out of the north,
then shift to the northeast tomorrow ahead of our next weather
system.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 6 PM Wednesday to noon CST Thursday
for Houston-Humphreys-Montgomery-Stewart.
&&
$$
DISCUSSION......21
AVIATION........Unger
Area Forecast Discussion
National Weather Service Portland OR
755 PM PST Tue Nov 13 2018
.SYNOPSIS...Offshore flow through the Gorge will continue to weaken
tonight and Wednesday. A weak frontal system passes over the area
tonight and Wednesday, but precipitation will favor the north half.
Another weak impulse drops southeast from British Columbia late
Thursday night and Friday morning. Strong high pressure returns over
the weekend and is expected to hold into early next week. This will
also result in another round of east wind through the Columbia Gorge.
&&
.SHORT TERM...Tonight through Friday...No changes. Previous
discussion follows. East wind continues through the Gorge this
afternoon, but not quite as strong as early this morning. At 21Z the
KTTD-KDLS gradient was around -6.0 mb. This was enough to produce 55
mph gusts at Crown Point and 40-45 mph at Corbett. 18Z NAM suggests
the KTTD-KDLS gradient will drop to around
-3.5 mb by 12Z Wed, which is several hours slower than the 12Z
version. This trend is more plausible considering the stratus field
piled up in the Central Gorge and Upper Hood River valley, which is
indicative of cross-Cascade flow. KTTD profiler indicates a rapid
weakening of the primary east wind core late this afternoon.
Another added forecast twist is the potential for California wildfire
smoke to be over the area. The 12Z HRRR 6000 ft AGL smoke product
indicates some degree of drift smoke to be over the region tonight.
The strengthening SW 850 mb flow will push it east late tonight and
Wed, but higher concentrations are possible over the south part of
the area, such as Lane County. Less cloud cover tonight and minimal
to no wind could lead to short-term periods of moderate to unhealthy
for sensitive groups air quality categories.
Although not in the forecast or grids, would not be surprised to see
isolated flurries fall out of the stratus field in the Central Gorge
and Upper Hood River Valley. Water vapor satellite imagery shows a
weakening low level front just inside 130W at 21Z that will likely
stall just off the Washington coast late this evening. The 12Z NAM
was a little slower with it, which makes sense as it enounters strong
surface high pressure. However, the 850 mb SW-W flow strengthens to
20-30 kt tonight and Wed. This should be enough to help scour the
cold air in the Central Gorge and Upper Hood River Valley. Rain still
appears very unlikely across our southern zones, including places
like Corvallis and Eugene. With the bulk of the upper level support
moving eastward across southern Canada Wed, the front should stall
out across our northern zones and fall apart Wednesday night into
early Thursday with rain chances decreasing fairly quickly during
that time.
H5 high pressure will be centered along 130-135W Thu night. This is
far enough offshore to allow short-waves within northwest flow aloft
to be in close proximity to the area. One such feature slides across
NE Washington 12Z Fri. Models suggest there may be enough cyclonic
curvature to the flow for a threat of precip in SW Washington and the
North Oregon Cascades from Mt. Hood northward. Southern interior
valleys will likely see areas of fog Thu night through Fri morning.
The upper ridge amplifies Friday afternoon, which will result in
light north low-level flow. Friday could be the start of air quality
issues due to weak transport wind and minimal surface flow.
Fortunately, the 850-700 mb mean layer flow Fri will be NW-N. This
would not be favorable for transport of California smoke into the
forecast area. Weishaar
.LONG TERM...Friday Night through Tuesday...No changes. Previous
discussion follows. Deterministic models are in agreement that a
sharp upper level ridge will remain over the forecast area from
Friday night into Saturday resulting in dry conditions. Both the GFS
and ECMWF show precipitation arriving along the coast by Monday
night as a weak front pushes on shore. This precipitation pattern
looks to stay in the extended forecast through Tuesday and into
Wednesday. Weak winds in the Willamette valley allow for the
persistence of early morning fog and temperatures trend slightly
downward and stay within seasonal norms. -BPhillips &&
.AVIATION...VFR conditions to begin with this evening, but a slow
moving cold front moving se across nw Oregon over the next 24 hours
will bring lowering cigs and chances for light rain. Cigs along the
north coast will be the first to lower, expected to drop into MVFR
category by 09Z. Further to the south and east cigs will be slower
to come down, as late as 18Z to 00Z in the south willamette Valley.
The likelihood of cigs dropping into MVFR category also decreases to
the south and east, although all locations in nw Oregon stand at
least a chance of doing so.
PDX AND APPROACHES...VFR conds to continue through at least 12Z Wed
morning, and perhaps longer. After 12Z there is an increasing chance
to see MVFR cigs settle in. Expect low end VFR to MVFR cigs to then
continue past 00Z Wed afternoon.
&&
.MARINE...No changes. Previous discussion follows. An approaching
cold front has slowed from earlier forecasts. SCA level winds of 21+
kts are sitting just outside the northwest corner of our waters per
an earlier satellite derived wind pass. Still expect gusts around 25
kt for tonight across the northern waters, but have delayed the
onset of the inner waters until about mid-evening. Have also delayed
the frontal passage by a few hours. Now expect the front will move
onshore around mid-day Wednesday with winds becoming light westerly
behind the front. High pres will build over the waters for Thu and
Fri, bringing a period of northerly winds. Then more offshore flow
is looking increasingly likely next weekend but not especially
strong at this point.
Seas will remain 5 ft then build into the 7 to 9 ft range tonight
with the front. A trailing dynamic swell train will then briefly bring
westerly seas near 10 ft Late wednesday night and early Thursday.
Seas than drop to between 5 and 8 feet for several days
thereafter. /JBonk
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory for winds until 10 AM PST Wednesday for
Waters from Cape Shoalwater WA to Cascade Head OR from 10
to 60 NM.
Small Craft Advisory for winds until noon PST Wednesday for
Coastal waters from Cape Shoalwater WA to Cascade Head OR
out 10 NM.
&&
$$
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This discussion is for Northwest Oregon and Southwest Washington
from the Cascade crest to 60 nautical miles offshore. This area is
commonly referred to as the forecast area.
Area Forecast Discussion
National Weather Service Reno NV
213 PM PST Tue Nov 13 2018
.SYNOPSIS...
High pressure will lead to dry and stagnant conditions through
the week. Localized degradation of air quality is possible under
valley inversions. A pattern change next week may open the door
for a couple of weak storm systems but heavy precipitation is
unlikely.
&&
.DISCUSSION...
Not much change in the overall ideas for the forecast the next 7
days. However, there were some minor adjustments in the next 36
hours with regards to smoke and haze from the Camp Fire, and the
potential storm next week.
The ridge remains with a weak wave passing into the Pacific
Northwest the next 24 hours. It will keep abundant high clouds
across the region. In addition, it is changing the flow aloft to a
light west. At the surface it normally wouldn`t mean much as
general light slow winds will continue. However, upslope winds on
the west slope of the Sierra will bring some smoke and haze east
of the crest later tonight into tomorrow. The HRRR smoke shows it
getting to almost I-80 by tomorrow afternoon and have added it to
the forecast as it fits the conceptual models. We aren`t sure just
how dense the smoke will be and associated air quality impacts,
but expect some reduced visibility in haze at a minimum. This
pattern will continue through Saturday, and if the Camp Fire
continues to produce a bunch of smoke, air quality will
deteriorate.
This weekend, the backdoor front that was depicted on the 00Z runs
is well east in the 12Z runs and ensembles. So there may be little
change, and a persistent pattern through Monday.
For the middle of next week, there is higher confidence in a
system moving in with some rain and snow. The ensembles all show
troughing along the West Coast by Wednesday. The details of how
much precip, and the snow levels will still need to be worked out.
What I can say is it doesn`t look any bigger than a routine winter
storm at best. The best news is that almost all ensemble runs do
NOT have a significant downslope wind event before the precip
moves in. Looking at the ensembles, the chances of a significant
downslope event are less than 20% as of this writing. X
&&
.AVIATION...
VFR with high clouds and light winds the next 24 hours. The
biggest impacts may be smoke from the Camp Fire after 12Z
Wednesday. Mtn obscuration may occur with the smoke and haze, with
the best chances of reduced visibility through Wednesday west of
a KSVE to Portola line. Smoke and visibility impacts may increase
later in the week if the Camp Fire continues to burn actively. X
&&
.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&
$$
For more information from the National Weather Service visit...
http://weather.gov/reno
Area Forecast Discussion
National Weather Service Sacramento CA
319 PM PST Tue Nov 13 2018
.SYNOPSIS...
Dry weather with cool nights and above average high temperatures
continues through the week. Diminishing winds ease critical fire
weather conditions, but widespread smoke from the Camp Fire will
continue to impact the area.
&&
.DISCUSSION...
Pacific short wave trof encountering the highly amplified ridge axis
over Wrn NOAM won`t bring any rain, but it is spreading a plethora
of high cloudiness over our CWA, masking the smoke layer from the
Camp WF in Butte Co. HRRR smoke loop suggests the smoke layer will
shift Ewd across the coastal range later today and overnite.
Otherwise, light/lighter winds and limited mixing height (generally
1 to 1.5 kft) will tend to keep persistent smoke over a large
portion of the region for the next couple of days.
Still looks as if this initial batch of high cloudiness will exit
our region Wed morning while additional high cloudiness will spill
over the persistent ridge Wed afternoon and Thu. This timing
suggests radiational cooling around sunrise could drop temps into
the low to mid 30s from MYV-MOD where some light frost could form in
outlying areas as humidities are forecast to recover now that the
Nly winds have subsided.
Without any major changes in the weather pattern through the end of
the week there is little daily change expected in the weather over
our region. Smoke is expected to keep temperatures locally cooler
the next couple of days, otherwise they will continue to run near or
above normal while mins run a few to several degrees below normal.
JHM
&&
.EXTENDED DISCUSSION (Saturday THROUGH Tuesday)
Ridging re-amplifies along the W coast this weekend as a GOA/Wrn
Canadian trof slides across the Canadian and Nrn Rockies. Most of
the max temps in the Valley will be in the 60s, with some low 70s in
the Nrn Sac Vly and surrounding foothills. These temps are about 10
degrees above normal N end of the Vly and many mtn locations to
about 5 degrees above south end of the Vly.
The wx pattern is forecast to change by Mon as low pressure forms
off the SOCAL coast with the lower heights allowing for a deeper,
longer wave trof to develop over the Ern Pac. There are now rumors
of rain over Norcal for the middle of next week, but model
differences continue to cause low confidence in timing and amounts.
13/00z ECMWF suggests as early as Tue nite into Wed and Thu, while
the GFS suggests some rain spreading into our area Wed and
continuing into Thu. However, the 13/12z ECMWF moves this system
through our region on Thu. Although the common theme for rain is
"mid week," the timing differences are problematic. The GFS
5-wave chart forecasts a displacement of the mean 5H ridge into
the mid section of NOAM with a mean trof over the Ern Pac near
130W which would support a pattern change. Have introduced some
PoPs Tue nite, the last grid block. JHM
&&
.AVIATION...
Widespread MVFR likely the next 24 hours across the entire
Sacramento Valley with local IFR conditions due to smoke from the
Butte County wildfire. Northerly winds under 10 knots.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&
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