Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/14/16
Area Forecast Discussion
National Weather Service Bismarck ND
957 PM CST Sun Nov 13 2016
.UPDATE...
Issued at 955 PM CST Sun Nov 13 2016
T/Td spreads at or near zero many places where the sky is clear.
HRRR continues to advertise fog development so will leave it in
the forecast for tonight with this update. Otherwise it is quiet,
will not be saying the same this coming Thursday/Friday.
UPDATE
Issued at 615 PM CST Sun Nov 13 2016
Inherited forecast looking good. I did add some patchy fog to my
central and some of my eastern counties as the HRRR suggests.
Winds will taper off over this area tonight near a surface ridge
allowing for radiational cooling and the potential for fog
development given some boundary layer moisture about.
&&
.SHORT TERM...(This evening through Monday)
Issued at 316 PM CST Sun Nov 13 2016
The short term begins with an upper level shortwave over the
northern Plains moving through a longwave ridge that has been
positioned over the central US for several days. Meanwhile a large
upper level low encompasses the Gulf of Alaska with weak ridging
over the Rockies into northern Alaska.
This afternoon and tonight an area of lower clouds will move
south with the cooler air behind the front and linger across the
north and east. There should be enough wind to mix the air and cloud
cover to hold temperatures up in the mid 30s most areas but lowered
mins to lower 30s southwest where past few nights it has gotten
cooler than expected...and also in the north central where the
coolest h850 temps will be.
Monday morning the weak upper level ridging moves east across the
northern plains and the flow flattens quickly as another shortwave
aloft pushes out of the Rockies and into the northern Plains. This
should bring plenty of high clouds along with some mild Pacific air
warm advection. Monday should be the warmest day of the upcoming
work week with highs in the lower 60s southwest and 50s elsewhere.
Used consmos for winds with the mild southwest flow. Also looked at
HRRR forecast min rh field for Monday afternoon - lowering the
blended guidance a tad - especially for the southwest.
.LONG TERM...(Monday night through Sunday)
Issued at 316 PM CST Sun Nov 13 2016
The long term will focus on the potential winter storm for the
latter part of the week and messaging the uncertainties. We have
issued a special weather statement regarding the potential for
significant winter weather Thursday/Friday. This would be the first
significant winter weather event of the season...and want to make
sure people are prepared.
Monday night through Wednesday will be rather benign with above
average temperatures continuing, though temperatures
will be trending lower Tuesday and Wednesday with highs
falling into the 50s Tuesday and 40s and 50s Wednesday.
The aforementioned upper level large Gulf of Alaska low digs south
and develops into a longwave trough off the west coast by Wednesday.
In response, the upper level flow over the northern Plains becomes
southwesterly and the models are depicting some upper level impulses
moving northeast across Montana and into northern ND and south
central Canada. This will bring a chance of rain showers - possibly
a few snow showers - late Tuesday night and Wednesday morning to the
northern tier of counties.
Regarding the potential winter storm system late this week:
GEFS ensemble plumes continue to show quite a disparity for
precipitation across the region highlighting the uncertainty for
picking any single solution at this time. However mean ensemble QPF
show a stronger signal for significant precipitation.
The 12z runs of the GFS and ECMWF show hints of these models
beginning to come a tad closer to an agreement. While the ECMWF
remains the faster solution...developing the surface low into
Nebraska by Thursday morning while the GFS develops it farther west
in CO/UT/WY by Thursday morning...the ECMWF is bringing the low
farther north across the ND/MN border, while the GFS tracks the low
from eastern SD into southern MN. The ECMWF brings the low to the
ND/MN border by daybreak Friday, while the GFS solution to the
surface low doesn`t bring it to the Red River Valley of SD/MN until
Saturday evening. The ECMWF continues to have the system exiting to
the Lake Superior/Hudson Bay area faster than the GFS.
Will continue to highlight the uncertainty in messaging and mention
impacts to travel Thursday and Friday in the Hazardous Weather
Outlook...and also by issuing a special weather statement. Will
continue to post to social media regarding the potential for
this storm system, as well as messaging regarding winter
preparedness for this potential first widespread significant winter
event for our area this season.
The 8 to 14 day temperature forecast does show a return to a
warmer than normal outlook so we don`t think the up-coming weather
will signal a cooler change yet.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 615 PM CST Sun Nov 13 2016
Areas of low VFR to MVFR cigs will be possible over portions of
central North Dakota this evening. In addition, patchy fog is
forecast to develop tonight into Monday morning along with
possible low stratus. This would include KMOT-KBIS-KJMS, where I
have mentioned VCFG for now. Remaining locations will remain VFR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...JV
LONG TERM...JV
AVIATION...NH
Area Forecast Discussion
National Weather Service Wilmington NC
922 PM EST Sun Nov 13 2016
.SYNOPSIS...
A weak low pressure system will bring rain across the area
through early Monday before exiting off to the northeast. High
pressure will follow, building slowly across the southeast
strengthening through mid week as it settles over the
Carolinas...bringing increasing sun and warmth. A strong cold
front will bring cooler weather by the end of next weekend.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
As of 915 PM Sunday...Rainfall steadily ending from south to
north this evening. Rain is mainly light to moderate with some
heavier patches moving through. Have leaned on the HRRR for the
very near term as it has been depicting the progression of the
rain-shield northward quite well. Based on this and radar
trends it looks like SC counties will be clear of precip in
another hour or so, with rain hanging in there quite a bit
longer for the Cape Fear/coastal areas. Previous discussion from
earlier this afternoon follows:
A trough/coastal front extends north from developing low
running up off the coast of the Carolinas while shallow cool
high pressure keeps a light northerly flow at the surface. The
southerly flow above the sfc will continue to produce some
decent isentropic lift resulting in intermittent light to
occasionally moderate bursts of rain spreading northward.
Sounding data shows column moistening up through tonight. The
temps this afternoon were holding in the low to mid 40s in the
Florence/Darlington area up to the mid 50s along the Cape Fear
coast, remaining steady due to clouds and rain.
Expect area to remain well entrenched in clouds and light to
moderate rain at times through tonight. Looking at the 295k
sfc, the best isentropic lift will occur through this evening
but becoming more concentrated along the coast toward midnight
as upper dynamics line up with decent lift along coastal front
reaching up right along the Cape Fear coast. Could see up to an
inch or so in spots. Potent mid to upper low will track east
from the southern Appalachians to the eastern Carolinas before
opening up and lifting north through Mon morning. The upper
dynamics associated with this low will continue to interact with
sfc front/low through tonight as it tracks to just off the Cape
Fear coast by daybreak Mon. Have included isolated
thunderstorms over waters, although would not rule out isolated
convection due some elevated instability just inland.
With low tracking up just off the coast, should see limited, if
any waa making it on shore. The soundings show a sharp inversion
near 1200 ft and expect a saturated column to keep a low stratus
layer to hold on into Mon morning. The influence of clouds and
a greater on shore flow just near the coast tonight, as low
tracks northward, should keep temps from dropping too much, with
readings between 55 and 60 along the coast while inland areas
will be in the mid 40s most places by daybreak in a continued
cooler northerly flow on the back end.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
As of 300 PM Sunday...Sfc low should be just off the Cape Fear
coast Monday morning. A very shallow cool air mass will be in
place and a sharp inversion just above with much warmer layer
just around 1500 to 2k ft. Expect this inversion to be tough to
break through much of Monday with low clouds hanging on much of
the day. Eventually drying through the mid levels will work its
way down as the sfc low exits off to the NE and mid to upper
low moves northeast and opens up, with light pcpn ending in the
morning from southwest to northeast.
The mid to upper low opens up through Mon morning as it lifts
off to the northeast, but deepening h5 trough will sweep
through on Tues. This will produce some clouds across the area
but overall expect drier air to makes its way in Tues scouring
the out the clouds leading to sunshine by afternoon.
Temperatures this period will be in the neighborhood of the 30
year normals for this time of the year. No freezing temps or
frost chances this period.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
As of 300 PM Sunday...Very little to discuss in the extended as
quiet weather is expected through the period. Longwave trough will
be moving offshore Wednesday, giving way to amplified mid-level
ridging blossoming from the Gulf Coast into the upcoming wknd. A
weak and dry cold front beneath the exiting trough will allow temps
Thursday to be the coolest of the period, but only subtly so as CAA
is weak so highs and lows will be around climo after slightly above
on Wednesday. Thereafter, temps climb steadily as the ridge builds
overhead and surface high pressure slowly migrates offshore. Temps
by Saturday will be 5-10 degrees above climo, low to mid 70s most
locations. A cold front will dig across the Carolinas Sunday beneath
a northern stream shortwave, but the guidance has trended weaker and
drier with this feature from previous runs. It appears moisture
return ahead of this is limited so will maintain sub-mentionable POP
with temps cooling back towards normal at the end of the period.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
As of 00Z...Water vapor shows a wave moving through the region.
Moderate isentropic lift will give us light to moderate rain over
much of the CWA through the overnight hours. Precipitation induced
ceilings will lower to IFR, with possible IFR visibilities due to
rain and fog later tonight. Northeast flow is expected through the
forecast period, becoming a bit more northwesterly as the low moves
northeast on Monday.
Extended Outlook...MVFR cigs late Monday will
transition to VFR as clouds decrease across the region. Otherwise
expect VFR in the extended aviation period.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
As of 915 PM Sunday...Latest obs continue to confirm exercise
caution headlines remain warranted over the waters. Previous
discussion from this afternoon follows:
Precautionary statement remains in effect for all waters
through Monday morning. Coastal trough/front is evident on
satellite winds just along the border of our local waters near
40 nm off shore. This will keep an on shore push beyond our
waters and northerly flow over the waters in a fair tight
pressure gradient. A developing sfc low off the GA coast will
track north maintaining winds between 10 and 20 kts most of the
night. Should see winds become more on shore closer to the coast
as low moves north reaching the Cape Fear coast by early Mon
morning. Seas will 3 to 5 ft primarily driven by wind driven
waves at 4 to 6 seconds.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
As of 300 PM Sunday...Surface low just off the Cape Fear coast
will move off to the NE through Monday. Weak high pressure will
build slowly in behind it with gradient relaxing through the
period. the higher on shore winds over NC waters early Monday
will diminish through the day leaving all waters 10 kts or less
Mon aftn through the remainder of the period. All winds will
become W to NW on back end of low as it exits off to the NE
allowing seas up to 4 ft early to quickly subside to less than 3
ft late Mon through Tues. WNA continues to indicate an ESE
long period up to 9 second swell dominating.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
As of 300 PM Sunday...Broad high pressure will leave NW winds across
the waters Wednesday, before a weak cold front moves offshore
Wednesday night followed by a wind shift to the North on Thursday.
These winds will then veer slowly to the NE on Friday as high
pressure expands along the coast. Strongest wind speeds will be late
Wed night and Thursday behind this front, reaching 10-15 kts from
the North. Otherwise, speeds will be 10 kts or less through the
period. Lack of a significant swell will allow wind waves to
dominate the spectrum, so the highest seas will occur during the
strongest winds. Wave heights of 2-4 ft will accompany the northerly
surge late Wed night and Thu, with 2-3 ft expected otherwise, 1-2 ft
near shore.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...Coastal Flood Advisory until 10 PM EST this evening for NCZ107.
MARINE...None.
&&
$$
SYNOPSIS...99
NEAR TERM...REK/RGZ
SHORT TERM...RGZ
LONG TERM...JDW
AVIATION...DL
MARINE...REK/JDW/RGZ
Area Forecast Discussion
National Weather Service Medford OR
512 PM PST Sun Nov 13 2016
Updated Aviation and Marine Discussions.
.DISCUSSION...Current visible image shows partly cloudy skies over
most of the area. This has resulted in mild temperatures. The
models are in fairly good agreement with the timing of the next
front with some minor differences. First the NAM and high res HRRR
are showing a slower arrival of the front and rain. Given the
models show a wave forming along the front this afternoon and it
is still nearly parallel to the upper flow suspect the slower NAM
and HRRR solution is correct and the forecast for this evening and
tonight will reflect this.
The front will gradually move into the area late tonight and remain
nearly stationary during the day Monday bringing an extended period
of wet weather. With favorable upslope flow from the southwest,
rainfall totals will be highest along the coast and coastal
mountains. Rain totals in those areas late tonight through Monday
night could range between 1-2 inches. The models hint at some
elevated instability Monday afternoon and evening, so could not rule
out an isolated thunderstorm or two. Not convinced anything will
happen, but could not rule it out either.
Both models are in pretty good agreement showing a weak surface low
forming along the front Monday evening, moving northeast Monday
night followed by a secondary front Tuesday afternoon. However they
have not been consistent with the timing of the front. The previous
run showed the NAM was the faster solution. Now its the GFS. Either
way we`ll be looking at another day of wet weather with the the
coast and coastal mountains.
Much colder air will begin to move into the area Tuesday evening and
snow levels will drop rather quickly to around 3500 over the west
side by early Wednesday morning. But could briefly lower to around
3000 feet in heavier showers. Therefore there is a good chance
travelers are likely to experience winter-like conditions with snow
covered roads for early morning commute. Especially for places like
Lake of the Woods, Diamond Lake, Crater Lake and highway 66.
Additionally, I-5 near Siskiyou summit could pick up an inch or so by
early Wednesday morning. In addition, models show 500mb temperatures
between -28 and -32C moving over the marine waters and coastline, so
have introduced a slight chance of thunderstorms.
An upper trough with a cold air mass aloft (the coldest so far this
season) will be overhead Wednesday with snow levels starting out
around 3500 feet, but could briefly lower to 3000 feet in heavier
showers. Showers will continue during the day Wednesday with a few
that could be moderate to heavy in the afternoon. Pass road
temperatures should warm up enough during the day to remain wet,
unless a heavier shower passes by in which case snow could briefly
accumulate on them. Keep in mind were still a few days out and
details on this could change, so watch for updates.
The upper trough axis will shift east Wednesday night and an upper
ridge will nose into southwest Oregon. However a moist northwest
flow will continue and while showers will be on the decrease, they
may not end completely along the Coast Range and Cascades. Also if
there`s enough breaks in the cloud cover, then temperatures could
drop near or below freezing over the passes resulting in icy roads.
Also temperatures could get close to freezing in portions of the
Rogue and Illinois Valley if there`s enough clearing, but
confidence on this is low. -Petrucelli
.EXTENDED DISCUSSION (Thursday through next Sunday)...
The upper trough axis will shift east Wednesday night and a ridge
will nose into coastal waters. This is slower than in yesterday`s
run. With a moist NW flow, showers will be on the decrease but may
not end completely along the Coast Range and Cascades. Also if
there`s enough breaks in the cloud cover, then temperatures could
drop near or below freezing over the passes resulting in icy roads.
Thursday night will be a transition day. The upper ridge will build
into the area bringing dry and milder weather. The ridge begin to
shift east Friday through Saturday as an upper low offshore slowly
moves east towards the Pac NW. Both models are coming into better
agreement and confidence is moderate that we will see light rain
spreading into the coastal counties on Friday, and possibly into the
Illinois Valley Friday afternoon/evening. Confidence is also
moderate that next weekend will be wet from the Cascades west,
possibly into the Klamath/Tulelake Basin as well. However, southerly
flow off the Siskiyou Mtns could again delay rain into the Rogue
Valley until mid way through next weekend. The current model trend
keeps Lakeview/Alturas dry until Sunday. /FB
&&
.AVIATION...14/00Z TAF cycle...VFR will continue over the
area this evening. A moist front will gradually move into the area
from the northwest and bring lowering cigs/vis. Ceilings will
gradually lower along the coast and MVFR with rain will arrive north
of Cape Blanco beginning around 06z. Cigs will lower to IFR with
MFR/IFR vis along the north coast tonight and MVFR along with local
of IFR will extend south of Cape Blanco overnight. These conditions
will continue along the coast Monday morning. A mix of widespread
MVFR and local IFR conditions are then expected along the coast
Monday afternoon. MVFR CIGS will spread inland into Douglas County
tonight and Monday morning with terrain becoming obscured. Ceilings
will lower along and west of the Cascades Monday morning with VFR
and areas of MVFR cigs as well as widespread terrain obscurations.
East of the Cascades and over Northern California expect VFR with
local MVFR conditions and areas of mountain obscurations developing
Monday morning through Monday afternoon. /CC
Note: The ceilometer at FAA site KOTH is out of service, so there
will be no ceiling observations available generally between the
hours of 04Z and 14Z.
&&
.MARINE...Updated 400 PM PST Sunday, 13 November 2016...
Steep seas and gusty south winds will develop again this evening and
tonight ahead of a cold front. Winds may briefly lower over portions
of the waters, mainly north of Cape Blanco, Monday morning. As a low
moves towards the area Monday afternoon and evening, winds and seas
are expected to increase further. Conditions will be hazardous to
small craft over the waters through early Monday afternoon. Then
winds and seas will increase Monday afternoon into Monday evening.
The 12z and 18z models support low end gales over the waters within
20 NM of shore from Gold Beach north during this period and a gale
watch is in effect for this area. Very steep seas are expected with
the gales. South of Gold Beach and beyond 20 NM from shore expect
conditions hazardous to small craft to continue due to a mix of
steep wind waves and west swell. Winds will gradually lower Monday
night and early Tuesday, but seas will remain elevated at or above
10 ft through at least Thursday. A stronger front is expected Friday
into Saturday and may bring gales along with very high and very
steep seas. /CC
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...None.
CA...None.
Pacific Coastal Waters...Gale Watch from Monday afternoon through
Monday evening for PZZ350-356-370-376.
Small Craft Advisory from 7 PM this evening to 2 PM PST Thursday
for PZZ350-356.
Small Craft Advisory until 2 PM PST Thursday for PZZ370-376.
$$
Area Forecast Discussion
National Weather Service Omaha/Valley NE
518 PM CST Sun Nov 13 2016
.SHORT TERM...(tonight through Thursday afternoon) issued at
315PM CST Sun Nov 13 2016
forecast concerns in the short term will mainly be above normal
temperatures/near record highs and dry weather...then attention
turns to the storm system Thursday night through Saturday.
Visible satellite imagery and metar observations show mainly clear
skies and warm southwest breezes ahead of a wind shift/cold front that
is moving into northeast Nebraska. h85 temperatures were around
+15 deg. C and good mixing has translated into temperatures in the
mid 60s.
A dry and cooler forecast for into Monday. A longwave h5 trough
is responsible for dragging the cold front through the area
tonight. Although the NAM12 does try to spread clouds northward
from Kansas toward Nebraska and nw MO/sw IA, the RAP tends to
limit these clouds. The northern stream of the trough lags the
southern stream and we could see some patchy mid clouds and high
clouds with this weak trough, then as the cirrus spills over the
ridge. Surface high pressure and light and variable winds should
allow temperatures to fall back into the 30s for most spots
tonight. Normal lows are a bit colder in the 20s.
The models are in good agreement that unseasonably warm weather
is on the way for Tuesday, Wednesday and Thursday. South flow
increases ahead of developing low pressure and a storm system
that will affect the Rockies. There is a weak frontal passage
Tuesday and this could help drop lows for Wednesday morning. Normal
highs are in the 40s, and we are forecasting highs in the 60s and
70s each day. The records for Tues./Wed/Thu are in the 70s and
Wednesday`s are particularly vulnerable -OMA 73/OFK 74/LNK 74.
Bumped up winds Thursday ahead of the frontal passage and boosted
highs as well.
.LONG TERM...(Thursday night through Sunday) Issued at 315 PM CST
Sun Nov 13 2016
By Thursday night, there are significant timing and location
differences with the storm system. Although the surface systems
are not as out of sync, the mid level systems are quite out of
sync. The EC is faster and weaker...while the GFS/Canadian are
slower and deeper over the Rockies. These differences account for
differing chances for rain/storms/snow. Our forecast area is
currently weaker on the deep moisture return with the EC and on
the southern fringe of where the better potential for snow is on
both the GFS/EC. Strong winds are expected Fri/Sat as well on the
backside of the cold front. Timing will likely be adjusted,
however we currently have a chance for showers Thursday night and
Friday. A few storms could develop ahead of the dry slot late
Thursday night or Friday a.m. A mix of rain/snow or rain changing
to snow in northeast Nebraska Friday night/Sat. a.m.
WPC hints that the spread of the models has increased since
yesterday and that lack of reliable data across parts of Canada
is contributing to these differences.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 516 PM CST Sun Nov 13 2016
VFR conditions are expected through Monday afternoon as only
scattered mid and high clouds are expected. A cold front sliding
through eastern Nebraska will turn winds from south or southwest
to northwest by Monday morning, but speeds will remain under 10kt.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
SHORT TERM...Zapotocny
LONG TERM...Zapotocny
AVIATION...Dergan
Area Forecast Discussion
National Weather Service Blacksburg VA
733 PM EST Sun Nov 13 2016
.SYNOPSIS...
High pressure across the region will shift east and weaken
tonight. Weak low pressure will pass southeast of the area
overnight before moving north across the Outer Banks Monday, and
just off the mid-Atlantic coast by Tuesday. Weak high pressure
follows this system Tuesday ahead of a dry cold front that will
cross the area on Wednesday.
&&
.NEAR TERM /THROUGH MONDAY/...
As of 725 PM EST Sunday...
Models seem too aggressive on moisture streaming northward early
this evening compared with obs/radar/satellite. Nudged pops/sky
cover and temps down according to latest HRRR and LAMP guidance.
Still looking at clouds increasing over the Piedmont and as far
west as the Blue Ridge by dawn with light rain starting to
saturate the lower and mid levels after midnight in southside VA/
NW NC piedmont. Still low pops expected through 12z Monday, with
20-30 pops from near FVX-INT east.
Previous afternoon discussion...
Dry air remains locked in place this afternoon with water vapor showing
a sharp gradient between very dry air aloft and deeper moisture just to
the south with the complex upper low. Seeing some northward advance of
mid deck toward southern sections across North Carolina but most fading
upon heading into the CWA per low humidity levels through the column.
Upper system to slowly head east passing across the Carolinas overnight
before helping give rise to a weak surface wave along the coast by
early Monday. However weak moisture transport to remain to the south/east
overnight as well as the best theta-e gradient aloft which should
again help focus better lift to the southeast of the region. This
also reflected in latest guidance solutions which tend to run deeper
moisture around the dry air overnight with only progged spotty showers
over the far south and east late. This supports trimming pops back
from north to south while leaving in some chance coverage southeast
third which may be generous given trends under such expansive dryness.
Otherwise increasing clouds southern/eastern half with skies remaining
mostly clear elsewhere until near dawn.
Low temps very tricky with potential for readings to fall fast per low
dewpoints this evening before likely rising a bit south after midnight
as clouds advance north. However how fast clouds arrive and northward
extent quite iffy given possible erosion of the canopy which could
allow for more 20s/lower 30s than expected. For now will continue with
this colder trend and only keep the far south and ridges in the 30s to
lower 40s pending clouds with 20s to lower 30s elsewhere.
Upper low will open up within the broad digging 500 mb trough Monday
with the surface reflection heading up along the Outer Banks to just
east of the Virginia Capes by late in the day. Expect this to keep the
swath of deeper moisture farther east closer to the coastal front where
more widespread showers will be likely. Inland rainfall looks dependent
upon weak overrunning within the faint wedge and under a weak
deformation zone associated with residual upper cold pool. Latest
models depict this scenario in only having spotty showers/light
rain across far eastern sections where PWATS climb to nearly an
inch with coverage quickly tapering off from the Blue Ridge west.
However as this feature edges north, could see a band of light
showers extend back across the north per latest EC, so extended
low pops back toward the Highlands during the afternoon. Otherwise
will continue to carry some chance pops mainly east of the
mountains Monday, with spotty coverage inland toward the Blue
Ridge, although low confidence with potential to only see clouds
and sprinkles outside of the Piedmont. Guidance temp spread
remains quite varied on Monday with range from 40s/low 50s to 60s
pending clouds/showers. For now to remain consistent, keeping
going trend of only seeing low/mid 50s east while the west should
be milder with 50s to lower 60s.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 230 PM EST Sunday...
Surface low pressure will track north along the Virginia coast
Monday night. Bulk of the rain will stay with the surface low,
however some much needed rain, even though little, could fall over
the piedmont as a deformation zone also tracks north Monday night.
Subsidence behind the departing coastal disturbance will bring
clearing skies, but clouds will increase during the day Tuesday as
upper level troughiness remains. Clouds Tuesday may look mean with
their dark bases, but they may only produce a few very isolated
showers or sprinkles during the afternoon. This upper level trough
will move east as a short wave digs over the Carolina Tuesday
evening.
Another disturbance will track east of the Great Lakes Tuesday night
into Wednesday. This system will send another mostly dry front over
the region Wednesday. High pressure will be centered along the Gulf
state with low pressure off the New England coast. The pressure
gradient between these two systems will bring breezy conditions to
the region Wednesday. High Pressure builds in from the
southwest quickly with winds decoupling Wednesday night.
Not much cold air behind any of the frontal passages this week.
Afternoon temperatures will be close to normal (50s west to lower
60s east). With less than ideal radiational cooling conditions
through the period, overnight lows will remain mild with mid 30s
across mountain valleys to the lower 40s east.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 245 PM EST Sunday...
Dry high pressure will stay anchored over the East Coast starting
Thursday and likely linger into the weekend. Models are hinting at a
frontal passage sometime this weekend. For now, the forecast would
have the front coming through the region Saturday into Saturday
night. However, if the ridge remains stubborn and hangs over the
East Coast, the front may not come through until Sunday or Monday.
In any case, this front looks moisture starved with light showers
over the mountains and dry east of the Blue Ridge.
While under this ridge, temperatures will moderate above normal
during the afternoon and remain mild overnight.
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
As of 640 PM EST Sunday...
Very dry air in place this evening is keeping cloud cover over the
Carolinas from advancing further north. Will lean this forecast
toward a drier solution, which for all TAF sites but Danville will
stay VFR through the period, and even confidence that Danville
will drop to MVFR is medium. However models agree that some
ceilings in the 2-3kft range may skirt Danville during the day
Monday.
Models do favor skies to become BKN-OVC late tonight into Monday
but mainly of the mid to high cloud variety.
As for precipitation, models tend to favor rain east of
Danville/Lynchburg so will not have any in the forecast.
Winds will remain light and variable through the period.
Extended aviation discussion...
Overall dry conditions return Tuesday-Friday with weak high
pressure in place, though a dry front moves across Wednesday with
little moisture. Overall, much of the new week appears to be VFR
at this time.
&&
.FIRE WEATHER...
As of 230 PM EST Sunday...
Very dry air will continue to linger into this evening with
humidity levels mostly between 10 and 20 percent late this
afternoon. However expecting gradual moisture recovery in the
valleys after sunset due to cooling and across southern sections
with clouds slowly increasing from the south through the
overnight. This should allow for decent humidity recovery espcly
late tonight although spots across the western ridges likely to
stay in the dry air with levels only rebounding to around 50-60
percent by daybreak Monday. However winds will again remain light
and variable to calm for the most part into Monday.
Low pressure forming along the Georgia/South Carolina coast
tonight will be moving north near the Outer Banks into Monday.
Will see clouds and subsequent shower chances increase by early
Monday...mainly east of the Blue Ridge. Rainfall amounts will be
light with only one to two tenths of rain expected for Southside
Virginia as well as the North Carolina Piedmont through Monday
afternoon. An added tenth or so will also be possible across
northern sections including parts of the southern Shenandoah
Valley and the Virginia Highlands by Monday evening. Otherwise
little rainfall is expected elsewhere at this time.
The pattern through the rest of the work week will be dry.
A weak front moves across Wednesday bringing another round of
gusty northwest winds for the middle of the week. The next threat
of showers appears to be with a front next weekend.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...JH/PH
NEAR TERM...JH/WP
SHORT TERM...RCS
LONG TERM...RCS
AVIATION...JH/WP
FIRE WEATHER...JH/KK/WP
Area Forecast Discussion
National Weather Service Bismarck ND
339 AM CST Mon Nov 14 2016
.SHORT TERM...(Today and tonight)
Issued at 339 AM CST Mon Nov 14 2016
Very mild weather is expected again today, despite a cool start
and patchy fog this morning.
As of 09 UTC, a surface ridge axis extends from Hettinger toward
Bismarck and Devils Lake. Efficient radiational cooling is taking
place across much of the area in association with that ridge axis
thanks to light winds, and in the case of central ND, clear skies.
As is often the case, model guidance, even MOS, is not capturing
the degree of observed cooling in the vicinity of that ridging at
the surface. Coupled with increasing high-level clouds streaming
into western ND in advance of a warm front, and it`s clear that
the temperature forecast through early this morning will remain a
rather low-confidence part of the short term forecast.
Otherwise, the influence of the surface ridge is also promoting an
environment favorable for patchy fog as has been observed in parts
of central ND since 05 UTC. HRRR simulations have been steadfast
in their depiction of fog potential continuing across central and
parts of northwest ND through about 15 UTC. The fog observed thus
far at the Bismarck airport has been shallow and transient, which
may be reflective of a shallow near-ground moist layer, so we are
not currently anticipating more than patchy fog anywhere.
For today, a warm front will advance eastward, reaching central ND
by afternoon. Temperatures at 850 mb will warm through the day and
by 21 UTC the multi-model consensus expects them to range from +7
C in north central ND to +12 C in the southwest. The scenario will
support highs ranging from the mid 50s F in the James River valley
to the mid 60s F in southwest ND, where winds are forecast to take
on a downslope westerly trajectory during the peak in heating and
mixing behind the warm front. We did lean toward the warmer edge
of guidance south and west of the Missouri River today given that,
but uncertainty in cloud cover trends kept us from advertising an
even warmer scenario. Some guidance did suggest a low-end shower
chance in western ND this morning ahead of the low- and mid-level
warm front, but forecast soundings from the 00 UTC GFS and NAM
suggested saturation will be relegated to the mid-levels, so we
maintained a dry forecast area-wide today for now.
Tonight, a cool front will move southeast through the area as a
weak mid-level shortwave trough moves across southern Canada in
quasi-zonal mean westerly flow at 500 mb. We are carrying a low
chance of showers in the north in close proximity to a powerful
150 kt 300-mb jet streak advertised by the 00 UTC global models.
Modest pressure rises are simulated behind the front, which may
yield breezy northwest winds in some areas after 06 UTC.
.LONG TERM...(Tuesday through Sunday)
Issued at 339 AM CST Mon Nov 14 2016
The key message in the long term is that high-impact winter
weather is probable across some part of the region Thursday and
Friday, but it`s too soon to be confident in the details of the
potential storm. Mild weather will continue in advance of that
with forecast highs of 45 to 55 F Tuesday and Wednesday.
The 00 UTC GFS, ECMWF, and CMC global model simulations remained
consistent in calling for a strong trough to dig into the Great
Basin by early Thursday before ejecting rapidly northeast into the
Northern Plains by Friday. However, each one of those global model
cores and their respective ensembles continue to offer up notable
differences in the details of this evolution, particularly with
the speed and path of what will likely be a negatively-tilted 500
mb trough and its associated downstream surface low. The 00 UTC
GFS remained the slowest, most wrapped-up and western-most of the
deterministic model solutions. Its run total liquid equivalent
QPF at Bismarck was nearly 2 inches, with a 500 mb low located in
northeast SD at 00 UTC Saturday. In contrast, the 00 UTC ECMWF
simulated only 0.60 inches of liquid-equivalent at Bismarck and
its 500 mb low was over Duluth by 00 UTC Saturday. Interestingly,
and perhaps tellingly, the 00 UTC GFS has been on the extreme end
of the GFS ensemble members with its QPF the last 24 hours. While
the GFS ensemble mean QPF values have risen, there`s substantial
spread, particularly when one considers that the GFS ensemble is
often under-dispersive. For example, at Bismarck, the spread in
total QPF from the 00 UTC GFS ensemble members ranges from only
0.15 inches to 2.36 inches. There are three distinct clusters of
solutions apparent in the ensemble plumes at Bismarck, so needless
to say, confidence in specific snowfall amounts is low at this
juncture. Ensemble and model spread is even larger at Minot and
Williston.
From a probabilistic standpoint, the full GFS and CMC ensemble set
with additional consideration from the ECMWF ensemble members does
yield about a 70% probability of enough QPF for headline-worthy
snow over south central ND into the James River valley. This will
be a dynamic trough and the surface low may deepen below 990 mb,
which means strong northerly winds are possible, too. Timing of
the heaviest snow is also still somewhat uncertain, but the peak
of impacts across western and central ND may be Thursday night
and Friday. Note too that some ensemble solutions suggest that a
warmer thermal structure could yield a rain-snow line somewhere
from south central into eastern ND, further complicating details
of the forecast.
Hemispheric flow will remain progressive, though, and without any
blocking the late-week storm should quickly exit the region by
early Saturday. Any snow cover left in its wake will serve as a
modulating influence on temperatures next weekend, though.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1211 AM CST Mon Nov 14 2016
Patchy fog is forecast to develop tonight into Monday morning
along with possible low stratus. This would include KMOT-KBIS-
KJMS, where I have mentioned VCFG for now. Remaining locations
will remain VFR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CJS
LONG TERM...CJS
AVIATION...NH
Area Forecast Discussion
National Weather Service Medford OR
926 PM PST Sun Nov 13 2016
.DISCUSSION...The area will be in active pattern of changing weather
this week while staying within the realm of what is typical for
this time of the year. First, on an astronomical note, high level
clouds in advance of a cold front are limiting the ability to see
the biggest and brightest supermoon in nearly 70 years. There are
occasional breaks in the cloud cover. The cloud cover appears to
be thinnest in southern Siskiyou County.
A forecast update has been issued to increase the probability of
precipitation for Josephine, Jackson, and northern Klamath
Counties on Monday...especially the afternoon. Light rain
associated with a slow moving cold front is occurring in northern
portions of Douglas and Coos Counties. It will make little
progress overnight with rain expected to spread southeast into
northern Curry County and around the vicinity of Roseburg. A wave
along the front is expected to enhance coastal rainfall amounts
during the afternoon on Monday with mainly moderate intensity
focused on Curry County. The forecast of around an inch of rain
for Curry County on Monday reflects a blend between the wetter GFS
and weaker ECMWF and NAM solutions. Southerly downslope winds will
hinder the starting time and quantity of rain in Jackson County.
But, the movement of the front and the aforementioned wave should
be enough to overcome the downslope in the afternoon. The front
and post-frontal showers will bring precipitation to much of the
area Monday night.
The next front on Tuesday will be a game changer in the extent
that it will send temperatures to near to slightly below normal
across the area for the first time this month. Snow
levels are likely drop to near or below pass levels on the
Cascades and Siskiyous Tuesday evening with around 1 to 3 inches
of snow overnight. A cooler/colder air mass will persist through
the remainder of the week. A focus for the night shift will be on
the probability of precipitation, precipitation amounts, and snow
levels through the week.
&&
.AVIATION...14/00Z TAF cycle...VFR will continue over the area this
evening. A moist front will gradually move into the area from the
northwest and bring lowering cigs/vis. Ceilings will gradually lower
along the coast and MVFR with rain will arrive north of Cape Blanco
beginning around 06z. Cigs will lower to IFR with MFR/IFR vis along
the north coast tonight and MVFR along with local of IFR will extend
south of Cape Blanco overnight. These conditions will continue along
the coast Monday morning. A mix of widespread MVFR and local IFR
conditions are then expected along the coast Monday afternoon. MVFR
CIGS will spread inland into Douglas County tonight and Monday
morning with terrain becoming obscured. Ceilings will lower along
and west of the Cascades Monday morning with VFR and areas of MVFR
cigs as well as widespread terrain obscurations.
East of the Cascades and over Northern California expect VFR with
local MVFR conditions and areas of mountain obscurations developing
Monday morning through Monday afternoon. -CC
Note: The ceilometer at FAA site KOTH is out of service, so there
will be no ceiling observations available generally between the
hours of 04Z and 14Z.
&&
.MARINE...Updated 830 PM PST Sunday, 13 November 2016... Steep
seas and gusty south winds will persist with conditions hazardous
to small craft into Monday afternoon. As a low moves towards the
area, winds and seas will increase further Monday afternoon and
evening. The 12z and 18z models support low end gales over the
waters within 20 NM of shore from Gold Beach north during this
period and a gale watch is in effect for this area. Very steep
seas are expected with the gales. South of Gold Beach and beyond
20 NM from shore expect conditions hazardous to small craft to
continue due to a mix of steep wind waves and west swell. Winds
will gradually lower Monday night and early Tuesday, but seas will
remain elevated at or above 10 ft through at least Thursday. A
stronger front is expected Friday into Saturday and may bring
gales along with very high and very steep seas. -CC/DW
&&
.PREV DISCUSSION... /Issued 512 PM PST Sun Nov 13 2016/
DISCUSSION...Current visible image shows partly cloudy skies over
most of the area. This has resulted in mild temperatures. The
models are in fairly good agreement with the timing of the next
front with some minor differences. First the NAM and high res HRRR
are showing a slower arrival of the front and rain. Given the
models show a wave forming along the front this afternoon and it
is still nearly parallel to the upper flow suspect the slower NAM
and HRRR solution is correct and the forecast for this evening and
tonight will reflect this.
The front will gradually move into the area late tonight and remain
nearly stationary during the day Monday bringing an extended period
of wet weather. With favorable upslope flow from the southwest,
rainfall totals will be highest along the coast and coastal
mountains. Rain totals in those areas late tonight through Monday
night could range between 1-2 inches. The models hint at some
elevated instability Monday afternoon and evening, so could not rule
out an isolated thunderstorm or two. Not convinced anything will
happen, but could not rule it out either.
Both models are in pretty good agreement showing a weak surface low
forming along the front Monday evening, moving northeast Monday
night followed by a secondary front Tuesday afternoon. However they
have not been consistent with the timing of the front. The previous
run showed the NAM was the faster solution. Now its the GFS. Either
way we`ll be looking at another day of wet weather with the the
coast and coastal mountains.
Much colder air will begin to move into the area Tuesday evening and
snow levels will drop rather quickly to around 3500 ft over the
west side by early Wednesday morning. But could briefly lower to
around 3000 feet in heavier showers. Therefore there is a good
chance travelers are likely to experience winter-like conditions
with snow covered roads for early morning commute. Especially for
places like Lake of the Woods, Diamond Lake, Crater Lake and
highway 66. Additionally, I-5 near Siskiyou summit could pick up
an inch or so by early Wednesday morning. In addition, models show
500mb temperatures between -28 and -32C moving over the marine
waters and coastline, so have introduced a slight chance of
thunderstorms.
An upper trough with a cold air mass aloft (the coldest so far this
season) will be overhead Wednesday with snow levels starting out
around 3500 feet, but could briefly lower to 3000 feet in heavier
showers. Showers will continue during the day Wednesday with a few
that could be moderate to heavy in the afternoon. Pass road
temperatures should warm up enough during the day to remain wet,
unless a heavier shower passes by in which case snow could briefly
accumulate on them. Keep in mind were still a few days out and
details on this could change, so watch for updates.
The upper trough axis will shift east Wednesday night and an upper
ridge will nose into southwest Oregon. However a moist northwest
flow will continue and while showers will be on the decrease, they
may not end completely along the Coast Range and Cascades. Also if
there`s enough breaks in the cloud cover, then temperatures could
drop near or below freezing over the passes resulting in icy roads.
Also temperatures could get close to freezing in portions of the
Rogue and Illinois Valley if there`s enough clearing, but
confidence on this is low. -Petrucelli
EXTENDED DISCUSSION (Thursday through next Sunday)...
The upper trough axis will shift east Wednesday night and a ridge
will nose into coastal waters. This is slower than in yesterday`s
run. With a moist NW flow, showers will be on the decrease but may
not end completely along the Coast Range and Cascades. Also if
there`s enough breaks in the cloud cover, then temperatures could
drop near or below freezing over the passes resulting in icy roads.
Thursday night will be a transition day. The upper ridge will build
into the area bringing dry and milder weather. The ridge begin to
shift east Friday through Saturday as an upper low offshore slowly
moves east towards the Pac NW. Both models are coming into better
agreement and confidence is moderate that we will see light rain
spreading into the coastal counties on Friday, and possibly into the
Illinois Valley Friday afternoon/evening. Confidence is also
moderate that next weekend will be wet from the Cascades west,
possibly into the Klamath/Tulelake Basin as well. However, southerly
flow off the Siskiyou Mtns could again delay rain into the Rogue
Valley until mid way through next weekend. The current model trend
keeps Lakeview/Alturas dry until Sunday. /FB
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...None.
CA...None.
Pacific Coastal Waters...Gale Watch from Monday afternoon through Monday
evening for PZZ350-356-370-376.
Small Craft Advisory until 2 PM PST Thursday for
PZZ350-356-370-376.
$$
DW/JRS/CC
Area Forecast Discussion
National Weather Service Marquette MI
459 AM EST Mon Nov 14 2016
.SHORT TERM...(Today and tonight)
Issued at 458 AM EST MON NOV 14 2016
WV imagery and RAP analysis indicated a weak mid level shortwave
trough from nw Ontario and nrn MN to ern South Dakota in a mainly
zonal pattern through the nrn CONUS and srn Canada. At the surface,
low pressure was located just east of Lake Superior with a cold
front extending to the west through the nrn Keweenaw peninsula and
wrn Lake Superior to near KHIB. IR loop and sfc obs indicated
increasing clouds through wrn Lake Superior with a more extensive
area of low clouds to the north through nrn Ontario.
Today and tonight, Satellite trends and fcst 950-850 rh suggest that
clouds will spread from nw to se through wrn Upper Michigan this
morning and through se cwa this afternoon behind the advancing cold
front. Upstream obs suggest that even though lower clouds will
prevail across the north by this afternoon there may be enough of dry
subcloud layer to limit drizzle chances. However, as ne low level
flow takes over, upslope locations may see the best chance for some
ocnl drizzle from this afternoon into this evening from Marquette
westward. Expect any pcpn to diminish overnight as winds diminish
with a weak sfc ridge building into the area.
CAA and increasing clouds will limit max temps to the upper 40s over
the nw. With the late increase in clouds, temps should still climb
into the mid 50s over the south and east. The clouds will also keep
temps from dropping off too far tonight with min readings in the mid
30s west to around 40 east and near the Great Lakes.
&&
.LONG TERM...(Monday night through Sunday)
Issued at 302 PM EST SUN NOV 13 2016
Elongated trough axis stretching from the mid-atlantic region to
Northern Ontario Mon ngt, with a weak surface low lifting northeast
across the upper peninsula. A secondary surface low over Northwest
Ontario late Mon ngt/early Tue will be coupled with a stronger
convergence zone and upper level dynamics to support light rain.
With downstream ridging across the North Atlantic/Eastern Quebec,
this should slow the forward progression of the trough negatively
tilted stretched trough, and produce a longer period of POPs through
Tue, then eventually pivot east with steady height rises late Tue
aftn/eve from west to east across the Upper Peninsula.
Guidance continues to prog an expansive surface ridge becoming
centered across the Ohio Valley and stretching north through the
Upper Midwest/Great Lakes Wed, and with a trough digging across the
four-corners region of the CONUS Thur, expect the 500mb ridging and
surface high pressure to continue an influence of dry/mild
conditions for the forecast area.
Ensembles and operational solutions then focus in on robust
shortwave ejecting northeast from the four-corners region of the
CONUS Fri. Operational solutions continue to differ on the precise
trajectory, but there is some indications that the trough axis that
departs to the east earlier in the week coupled with the amplified
500mb ridge, could steer next weekends surface feature further
northwest across Northern Minnesota into Ontario. There remains good
agreement that some stronger cold air advection will pivot around
the backend of the surface feature Sat/Sun, and temps will likely
struggle to warm beyond the low/mid 30s with periods of a rain/snow
mix next weekend.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1231 AM EST MON NOV 14 2016
Expect VFR conditions to persist thru sunrise as a slowly weakening
w flow ahead of an aprchg cold fnt continues to draw llvl dry air
into the Upper Lks. Following the cold fropa this mrng and a wshft
to the n, moister llvl air wl arrive and result in deteriorating
cigs. The best chc for IFR conditions and perhaps some drizzle/fog
wl be at SAW and IWD, where the llvl n wind wl present a sharper
upslope component.
&&
.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 458 AM EST MON NOV 14 2016
Northeast winds to around 20 knots will diminish tonight to less
than 10 knots as a ridge builds into the area. Northwest winds may
increase to 30 knots by Tuesday night behind a trough moving through
the region. The next chance for gales, especially over the wrn lake,
is expected by Thursday night into Friday as northeast winds
increase in response to a deep low pressure system approaching from
the plains. Uncertainty remains with the track of that low.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...Beachler
AVIATION...KC
MARINE...JLB
Area Forecast Discussion
National Weather Service Bismarck ND
833 AM CST Mon Nov 14 2016
.UPDATE...
Issued at 832 AM CST Mon Nov 14 2016
Patchy fog has been gradually diminishing this morning over many
locations, and will continue to do so. Some light showers over the
west continue to push easterly. Have added some low precipitation
chances going towards the east for these showers in line with
latest HRRR run. Updates have been sent.
UPDATE Issued at 624 AM CST Mon Nov 14 2016
Refined the patchy fog using web cams and airport data. Not
widespread but patchy. Radar data shows more returns across the
northwest. Most probably not reaching the ground but expanded
the slight chance for rain northwest quarter for a few hours.
UPDATE Issued at 450 AM CST Mon Nov 14 2016
Quick update to go ahead and introduce a slight chance of showers
to west central and northwest ND this morning based on the radar
trends upstream, and a report of light rain beneath them in the
last hour at Glasgow, MT. We still believe much of the moisture
will evaporate before reaching the ground given the relatively
dry lower atmosphere, though.
&&
.SHORT TERM...(Today and tonight)
Issued at 339 AM CST Mon Nov 14 2016
Very mild weather is expected again today, despite a cool start
and patchy fog this morning.
As of 09 UTC, a surface ridge axis extends from Hettinger toward
Bismarck and Devils Lake. Efficient radiational cooling is taking
place across much of the area in association with that ridge axis
thanks to light winds, and in the case of central ND, clear skies.
As is often the case, model guidance, even MOS, is not capturing
the degree of observed cooling in the vicinity of that ridging at
the surface. Coupled with increasing high-level clouds streaming
into western ND in advance of a warm front, and it`s clear that
the temperature forecast through early this morning will remain a
rather low-confidence part of the short term forecast.
Otherwise, the influence of the surface ridge is also promoting an
environment favorable for patchy fog as has been observed in parts
of central ND since 05 UTC. HRRR simulations have been steadfast
in their depiction of fog potential continuing across central and
parts of northwest ND through about 15 UTC. The fog observed thus
far at the Bismarck airport has been shallow and transient, which
may be reflective of a shallow near-ground moist layer, so we are
not currently anticipating more than patchy fog anywhere.
For today, a warm front will advance eastward, reaching central ND
by afternoon. Temperatures at 850 mb will warm through the day and
by 21 UTC the multi-model consensus expects them to range from +7
C in north central ND to +12 C in the southwest. The scenario will
support highs ranging from the mid 50s F in the James River valley
to the mid 60s F in southwest ND, where winds are forecast to take
on a downslope westerly trajectory during the peak in heating and
mixing behind the warm front. We did lean toward the warmer edge
of guidance south and west of the Missouri River today given that,
but uncertainty in cloud cover trends kept us from advertising an
even warmer scenario. Some guidance did suggest a low-end shower
chance in western ND this morning ahead of the low- and mid-level
warm front, but forecast soundings from the 00 UTC GFS and NAM
suggested saturation will be relegated to the mid-levels, so we
maintained a dry forecast area-wide today for now.
Tonight, a cool front will move southeast through the area as a
weak mid-level shortwave trough moves across southern Canada in
quasi-zonal mean westerly flow at 500 mb. We are carrying a low
chance of showers in the north in close proximity to a powerful
150 kt 300-mb jet streak advertised by the 00 UTC global models.
Modest pressure rises are simulated behind the front, which may
yield breezy northwest winds in some areas after 06 UTC.
.LONG TERM...(Tuesday through Sunday)
Issued at 339 AM CST Mon Nov 14 2016
The key message in the long term is that high-impact winter
weather is probable across some part of the region Thursday and
Friday, but it`s too soon to be confident in the details of the
potential storm. Mild weather will continue in advance of that
with forecast highs of 45 to 55 F Tuesday and Wednesday.
The 00 UTC GFS, ECMWF, and CMC global model simulations remained
consistent in calling for a strong trough to dig into the Great
Basin by early Thursday before ejecting rapidly northeast into the
Northern Plains by Friday. However, each one of those global model
cores and their respective ensembles continue to offer up notable
differences in the details of this evolution, particularly with
the speed and path of what will likely be a negatively-tilted 500
mb trough and its associated downstream surface low. The 00 UTC
GFS remained the slowest, most wrapped-up and western-most of the
deterministic model solutions. Its run total liquid equivalent
QPF at Bismarck was nearly 2 inches, with a 500 mb low located in
northeast SD at 00 UTC Saturday. In contrast, the 00 UTC ECMWF
simulated only 0.60 inches of liquid-equivalent at Bismarck and
its 500 mb low was over Duluth by 00 UTC Saturday. Interestingly,
and perhaps tellingly, the 00 UTC GFS has been on the extreme end
of the GFS ensemble members with its QPF the last 24 hours. While
the GFS ensemble mean QPF values have risen, there`s substantial
spread, particularly when one considers that the GFS ensemble is
often under-dispersive. For example, at Bismarck, the spread in
total QPF from the 00 UTC GFS ensemble members ranges from only
0.15 inches to 2.36 inches. There are three distinct clusters of
solutions apparent in the ensemble plumes at Bismarck, so needless
to say, confidence in specific snowfall amounts is low at this
juncture. Ensemble and model spread is even larger at Minot and
Williston.
From a probabilistic standpoint, the full GFS and CMC ensemble set
with additional consideration from the ECMWF ensemble members does
yield about a 70% probability of enough QPF for headline-worthy
snow over south central ND into the James River valley. This will
be a dynamic trough and the surface low may deepen below 990 mb,
which means strong northerly winds are possible, too. Timing of
the heaviest snow is also still somewhat uncertain, but the peak
of impacts across western and central ND may be Thursday night
and Friday. Note too that some ensemble solutions suggest that a
warmer thermal structure could yield a rain-snow line somewhere
from south central into eastern ND, further complicating details
of the forecast.
Hemispheric flow will remain progressive, though, and without any
blocking the late-week storm should quickly exit the region by
early Saturday. Any snow cover left in its wake will serve as a
modulating influence on temperatures next weekend, though.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 624 AM CST Mon Nov 14 2016
Patchy fog will mean a few hours if Low IFR at KBIS through 14z.
Otherwise vfr expected across the region. later today (after 00z)
expect some wind shear to develop kbis-kdik-kmot-kisn as low level
winds increase.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JJS
SHORT TERM...CJS
LONG TERM...CJS
AVIATION...WAA
Area Forecast Discussion
National Weather Service Grand Rapids MI
1038 AM EST Mon Nov 14 2016
LATEST UPDATE...
Update
.SYNOPSIS...
Issued at 308 AM EST Mon Nov 14 2016
A mild week is expected with highs climbing into the lower to mid
60s by Thursday and Friday before a strong cold front moves through
early in the weekend and temperatures fall into the 30s and 40s by
the end of the weekend.
A dry week is expected too with low chance of rain showers late
Tuesday as a trough moves across the Great Lakes.
&&
.UPDATE...
Issued at 1038 AM EST Mon Nov 14 2016
Have tweaked sky cover up through the rest of the day to account
for high clouds already over Lower Michigan. RAP model soundings
and RH overview reveal a more saturated layer at 25 kft this
afternoon and evening. Temperature forecast remains on track, with
highs in the mid to upper 50s later today. Despite increasing
cloud cover, added some patchy fog to the forecast late tonight
into mid-morning Tue. Boundary layer RH ramps up tonight,
especially after 06z, so expecting more low clouds/fog. Winds will
also go calm overnight. The increase in moisture should help keep
min temps tonight in the upper 30s to low 40s.
&&
.SHORT TERM...(Today through Wednesday)
Issued at 308 AM EST Mon Nov 14 2016
Forecast concerns are minimal this morning. Latest ir loop shows
fair skies from New England west to the Plains. A couple of upper
troughs are generating some high clouds over the Great Lakes, but
not much more than that.
Sfc analysis shows a weak cold front stretching from western Lake
Superior southwest to the Oklahoma panhandle. This front will move
east and cross Lower Michigan late Tuesday. There is a decent short
wave progd with the front but much of the energy remains north of
the cwa. Consequently, that`s how we have drawn the pop gradient:
highest pops north. Much of the cwa will remain dry. However,
northeast of a Pentwater to Lansing line a brief shower is possible
late Tuesday afternoon and Tuesday evening as the cold front moves
through.
A sunny day is expected today, then clouds will increase Tuesday as
the front moves closer. Skies will become mostly sunny again by
Wednesday as the front moves east.
.LONG TERM...(Wednesday night through Sunday)
Issued at 308 AM EST Mon Nov 14 2016
e are looking at dry conditions with warming temperatures into Fri.
We will then see a transition to much colder temperatures with rain
showers changing to snow showers for the weekend.
We are looking at temperatures likely gradually warming well into
the 60s by Friday. We will see the strong upper ridge to our west on
Wed, build across the region through Thu. The real warming will take
place on Thu and Fri as a strong srly wind will develop out ahead of
the intensifying area of low pressure across the Plains. We should
stay dry until Fri when the strong cold front approaches.
Colder air will start to move in behind the front on Fri night, but
the core of it will come in on Sat/Sat evening. Strong winds will
usher this cold air in. We will see a dry slot move through
immediately after the frontal passage. The cold pool aloft and the
coldest low level air will move through on Sat, bringing the wrap
around pcpn in. Timing between the models are a little different for
the change over from rain to snow. We have gone with a compromise
and started to transition it Sat afternoon with all snow Sat night
and beyond based on low enough wet bulb zero heights.
Lake effect will become a player to as the colder air moves in later
Sat. Delta T`s will increase to over 20c by Sunday. We could see
some accums for NW flow favored areas, especially Sat night when
temps will be down toward or below freezing.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 612 AM EST Mon Nov 14 2016
VFR conditions expected until late tonight. Moisture will pool
ahead of a weak cold front and the layer near the sfc will
saturate. This will lead to some fog and perhaps IFR cigs after
09z.
&&
.MARINE...
Issued at 308 AM EST Mon Nov 14 2016
We`ll continue with the small craft advisory until 7 am. Waves are a
bit above 4 feet but decreasing slowly. Should be under advisory
criteria by 7 am.
&&
.HYDROLOGY...
Issued at 313 PM EST Sat Nov 12 2016
Area rivers are below bankfull and falling. A few in the Grand River
basin remain above normal for November. No significant rainfall
events are expected in the next week, so levels should continue to
fall.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&
$$
UPDATE...EBW
SYNOPSIS...04
SHORT TERM...04
LONG TERM...NJJ
AVIATION...04
HYDROLOGY...63
MARINE...04
Area Forecast Discussion
National Weather Service Marquette MI
653 AM EST Mon Nov 14 2016
.SHORT TERM...(Today and tonight)
Issued at 459 AM EST MON NOV 14 2016
WV imagery and RAP analysis indicated a weak mid level shortwave
trough from nw Ontario and nrn MN to ern South Dakota in a mainly
zonal pattern through the nrn CONUS and srn Canada. At the surface,
low pressure was located just east of Lake Superior with a cold
front extending to the west through the nrn Keweenaw peninsula and
wrn Lake Superior to near KHIB. IR loop and sfc obs indicated
increasing clouds through wrn Lake Superior with a more extensive
area of low clouds to the north through nrn Ontario.
Today and tonight, Satellite trends and fcst 950-850 rh suggest that
clouds will spread from nw to se through wrn Upper Michigan this
morning and through se cwa this afternoon. Upstream obs suggest that
even though lower clouds will prevail across the north by this
afternoon there may be enough of dry subcloud layer to limit drizzle
chances. However, as ne low level flow takes over, upslope locations
may see some ocnl drizzle from this afternoon into this evening from
Marquette westward. Expect any pcpn to diminish overnight as winds
diminish with a weak sfc ridge building into the area.
CAA and increasing clouds will limit max temps to the upper 40s over
the nw. With the late increase in clouds, temps should still climb
into the mid 50s over the south and east. The clouds will also keep
temps from dropping off too far tonight with min readings in the mid
30s west to around 40 east and near the Great Lakes.
.LONG TERM...(Tuesday through Sunday)
Issued at 456 AM EST MON NOV 14 2016
A persistent Pacific airflow wl continue the relatively warm and
mainly dry wx for Upper MI until at least late week. But later in
the week the pattern is expected to amplify, as a stronger
disturbance/low pres system lifts ne from the Four Corners region and
brings in some pcpn on Fri and likely some accumulating lake effect
snow in its wake next weekend.
Beginning Tue...Another shortwave emerging from the Pac NW will move
east along the Canadian border today then east-southeast thru the
Northern Plains tonight into the Upper Lakes on Tue. Models have
trended weaker with this shortwave and its associated forcing since
last night`s runs which is reflected in weaker fcst q-vector
convergence and 5h height falls. Still, with limited moisture inflow
and the better upper dynamics and sfc low pres fcst to move well
north into Canada, expect enough low-level convergence along the
passing sfc trough to support a period of light rain moving through
the forecast area Tue into Tue evening. With the Pacific airflow
and h85 temps in the 2-4C range, above normal temps are still
expected.
Wed/Thu...Large scale ridging/subsidence in the wake of the
departing shortwave wl bring a drying trend Tue night into Wed. As
the ridge axis shifts to the e on Wed and the wind shifts to the sw,
increasing waa clouds are expected later Wed into Thu. Unseasonably
warm Pacific air wl continue to dominate during this time with h85
temps rising as high as 6-8C Wed night into Thu.
Fri into Sun...Longer range models continue to show a good deal of
variability on the track...timing and intensity of the shortwave/sfc
low pres emerging from the Four Corners region of the CONUS and
tracking ne thru the Plains and toward the western Great Lakes. In
general, the GFS model has shown the best run-to-run continuity for
the past several days advertising a slower and deeper sfc low
tracking toward the far western forecast area Fri night which would
suggest mainly a rain event through at least Fri night before the
arrival of much colder air in nnw flow on backside of system
produces accumulating lake effect snow downwind of Lake Superior.
The last few runs of the ECMWF have trended toward the farther west
track of the GFS but is much quicker (almost 12 hours) with timing
and more progressive. The Canadian model had been more consistent
with the GFS the last few days, but now on the latest 00z run is
showing a more progressive and farther east solution consistent with
previous runs of the ECMWF from a few days ago. Given better
consistency exhibited by GFS will tend to lean more toward its
solution for forecast details. As a result would expect bulk of
synoptic pcpn to be mostly in form of rain for our area late Thu
night into Fri night with a quick transition to lake enhanced/lake
effect snow on Sat for far western counties and Sat evening over the
north central counties. Several inches of lake effect snow
accumulation looks possible before the snow tapers off from west to
east on Sun with weakening cyclonic northerly flow and increasing
ridging/subsidence from the north and west.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 652 AM EST MON NOV 14 2016
Following a cold fropa this morning and a wind shift to the north,
moisture low level air will arrive and result in lowering cigs. The
best chc for IFR conditions and perhaps some drizzle/fog will be at
SAW and IWD, where the low leve north wind will present a sharper
upslope component.
&&
.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 459 AM EST MON NOV 14 2016
Northeast winds to around 20 knots will diminish tonight to less
than 10 knots as a ridge builds into the area. Northwest winds may
increase to 30 knots by Tuesday night behind a trough moving through
the region. The next chance for gales, especially over the wrn lake,
is expected by Thursday night into Friday as northeast winds
increase in response to a deep low pressure system approaching from
the plains. Uncertainty remains with the track of that low.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...Voss
AVIATION...JLB
MARINE...JLB
Area Forecast Discussion
National Weather Service Portland Oregon
251 AM PST Mon Nov 14 2016
.SYNOPSIS... Rather wet today as a front stalls over the region. This
front will finally be pushed east of the region later tonight. Then
much cooler air aloft arrives, ensuring showers for Tue and Wed. Snow
levels will lower, and be down at or just below major passes in the
Cascades Tue night. Brief break in the weather for Thu into Fri, but
rain and breezy conditions arrive for the weekend.
&&
.SHORT TERM...Today through Wednesday..
As expected, the cold front is slowly pushing into western WA and far
northwest Oregon. Rain will transition over to showers and decrease
in those areas this am. But the front will stall over western Oregon
today, with rain continuing, mainly south of a Tillamook to Portland
to Mt St Helens.
NOAA satellite imagery showing rather steady feed of moisture riding
on southwesterly flow aloft into the region. Do have a few waves
along the front in that band, which will bring occasional bursts of
heavier rain to the region, but again this will likely be to south of
the aforementioned line. Strongest wave on this band will develop bit
more as it approaches later this afternoon and evening. This wave,
with its surface based low pressure area, will act to pull the rain
back northward across the region. Models have differed on strength of
the low, but now think blend of the ECMWF and GFS seems reasonable
with a weaker low than the NAM has been suggesting. So, this will
keep winds along the coast in the 15 to 30 mph range at worst, with
gusts mostly 40 to 45 mph this evening.
As the low moves onshore near Astoria later tonight, it will push a
cold front across the region, with rain transitioning to showers at
that time. Air mass will becoming unstable on Tue, as much cooler air
aloft arrives. This will provide for plenty of showers, and perhaps a
thunderstorm or two along the coast and across the coastal waters.
Showers will continue into Wed, though showers will be slowly
decreasing on Wed as most of the upper support for showers begins
shifting into northern California. With much lower snow levels,
would not be surprised to see stronger showers produce some small
hail on Tue.
Snow level stay around 6000 to 7000 ft today into tonight, but as the
colder air arrives on Tue, it will gradually lower to around 4000 ft
by Tue evening, and then hover near 3000 to 3500 ft Tue night and
Wed. All depends on where showers line up, but good potential of 3 to
6 inches of new snow on the major passes in the Cascades for Tue
night through Wed afternoon. Rockey.
.LONG TERM...Wednesday night through Sunday...The upper level trough
axis looks to be east of the Cascades by Wednesday night, but cold
air aloft will keep at least a chance of showers over the forecast
area through Thursday morning. Upper level ridging then builds into
the Pac NW by Thursday evening bringing drier conditions. Surface
flow turns offshore by Friday, with gusty east wind possible in the
usual locations. The active weather pattern likely develops late
next week with another frontal system expected to move across the
region Friday night and Saturday. Post frontal showers look to
continue into Sunday. /64
&&
.AVIATION...Cold front may have stalled out south of KAST and
north of KTMK. Rain along the front is somewhat of a hybrid
stratiform and convective regime with MVFR cigs and occasional IFR
Vsbys nearer the frontal boundary and VFR still to the south and
east. Still expect the front will drift south over the next few
hours and bring MVFR cigs. Guidance is all over the place
thereafter with a mix of IFR to MVFR Vsbys with predominantly MVFR
Cigs but pockets of IFR CIGS at the coast and KHIO as well. Thus,
have a low confidence 12z TAF package ahead and will likely follow
the overall HRRR and LAMP MOS trends given the more frequent
update cycle. Conditions generally improve for several hours
beginning 19-21z before deteriorating again under the next passing
frontal system 15/01-04z.
KPDX AND APPROACHES...VFR though MVFR conditions increasingly likely
after by 12z. Forecast is very low confidence as cold front is not
yet showing much sign of solid movement. If nothing else for this
morning`s push, 10L/R approaches will likely remain MVFR with
cigs around 015. VFR Cigs should return after 20Z with light
easterly flow, however visual approaches will likely remain
impacted through the evening push. MVFR cigs 020-030 return for
the Tuesday boxer arrivals. /JBonk
&&
.MARINE...Cold front has stalled along a NE-SW line somewhere
between the Columbia Bar and Tillamook Bar. Winds have remained
below Gales for the last few hours but are likely locally knocking
on the bottom end of gale criteria. Will need to see if the SCA
for winds can be dropped at 4 am as planned. Seas will stay 9-11
feet until around 10 am but only fall just below 10 feet for
several hours.
Another wave will form along the stalled frontal boundary this
evening into Tue. This will bring a warm front through the
waters, resulting in a short several hour period of small craft
advisory winds. Models have come into agreement with winds staying
below gale criteria. Seas will also return into the low teens
under a persistent westerly swell. Winds then drop off for the
middle of the week as a showery upper level low moves over the
region. Then another potentially much stronger front looks to be
on tap for the end of the week. JBonk/mh
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory for hazardous seas on all coastal
waters until 10 today, then again for tonight
through Thu afternoon.
Small Craft Advisory for winds until 4 AM today for
Coastal Waters from Cascade Head to Florence.
Small Craft Advisory for winds from 7 PM this evening
to 2 am Tue on all Coastal Waters.
Small Craft Advisory for Rough Columbia River Bar until 8 PM
PST this evening.
&&
$$
Interact with us via social media:
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This discussion is for Northwest Oregon and Southwest Washington
from the Cascade crest to 60 nautical miles offshore. The area is
commonly referred to as the forecast area.
Area Forecast Discussion
National Weather Service Wakefield VA
355 PM EST Mon Nov 14 2016
.SYNOPSIS...
Low pressure slowly lifts northeast along the Mid Atlantic coast
tonight. The low moves well off to the northeast Tuesday as high
pressure builds over the Southeast states. A weak trough of low
pressure pushes through the Mid Atlantic and Northeast states on
Wednesday...with high pressure then building over the area
Thursday and Friday.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Latest surface analysis centers low pressure over eastern North
Carolina this afternoon. High pressure over the western Atlantic
remains wedged into central Virginia and the Piedmont. Light to
moderate rain continues across the Piedmont into central Virginia,
with another area of light rain over the Eastern Shore and coastal
waters. Rain has taped off across southern Virginia and northeast
North Carolina with some clearing even observed on satellite. Per
RAP analysis, vorticity maxima has lifted into eastern Virginia as
additional height falls arrive over the Piedmont ahead of the next
approaching shortwave. These features, in concert with theta-e
advection will result in ongoing rain across the Piedmont into
central Virginia and along the coast through late today. Have
trimmed back POPs across the southeast as dry air gets wrapped
into the system. Rainfall amounts expected to remain at or below
one quarter of an inch, but amounts up to one half inch are
possible in areas that see a longer duration of light to moderate
rain pivoting around the surface low. Highest amounts expected
along the coastal Eastern Shore and over the northern Piedmont.
Temperatures generally range from the mid to upper 40`s inland to
the low to mid 60`s southeast.
The surface low lifts just offshore of the Mid-Atlantic coast
tonight, with the deepest moisture pivoting northeastward along
the coast. NAM and GFS 300K isentropic analysis indicates
sufficient lift in the low levels for ongoing rain generally along
and north of Interstate 64 through this evening. Precipitation
tapers southwest to northeast late tonight, but low clouds
expected to linger through late tonight. Perhaps some clearing
across the far southwest per model soundings. Lows tonight range
from the upper 30`s Piedmont to the mid/upper 40`s along the coast
and Eastern Shore.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
Additional energy digging from the Midwest into the Southeast
will reinforce the Eastern US trough Tuesday. The coastal low
lifts along the Northeast coast as high pressure centered over the
Southern Plains extends northeast into the local area. Lagging
upper level dynamics and low level moisture will result in a
mostly cloudy to cloudy sky Tuesday morning across the northeast
half of the forecast area, before clearing in the afternoon. Also
expect lingering light rain for the Maryland Eastern Shore through
late morning. Farther south and west, expect a mostly sunny sky.
Seasonable, with highs in the upper 50`s to around 60 north to the
low to mid 60`s south. Mostly clear Tuesday night with lows in the
mid to upper 30`s inland to the low to mid 40`s near the coast.
The next northern stream disturbance digs into the northern Mid-
Atlantic region Wednesday morning. An associated cold front is
forecast to push across the forecast area during the afternoon.
Moisture will be limited along the boundary, with precipitable
waters at or below one half inch. The exception will be the
northeast, where soundings indicate moist mid levels and
precipitable waters around three quarters of an inch. The added
dynamics may be enough to overcome the limited moisture and dry
sub-cloud layer Wednesday afternoon into Wednesday evening. Will
retain slight chance POP`s generally north and east of Interstate
64. Sky averages mostly sunny southwest to partly cloudy (possible
mostly cloudy for a time Wednesday afternoon) northeast. Highs
generally in the low to mid 60`s. Shortwave pushes offshore late
Wednesday night as the front pushes offshore. Clearing late, with
lows generally in the upper 30`s to low 40`s inland to mid to
upper 40`s near the coast.
Heights build Thursday as an anomalous upper level ridge builds
over the eastern half of the US. High pressure builds into the
region, centering over the Mid-Atlantic region Thursday afternoon.
850Mb temperatures warm to around +10 to +12C (+1 standard
deviation). However, northwest flow will help keep temperatures
in check, with daytime highs generally in the mid to upper 60`s
inland to low 60`s along the coast. Sky will be sunny.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
The long term begins with an upper level ridge over the area
providing dry and mild weather. An upper level trough over the Great
Plains will move east and dig south through the Mid Atlantic States
by Sunday. A cold front is progged to cross the area Saturday
evening. Moisture with the front will be limited but have POPS of 20
to 30 percent affecting the CWA with light rain showers. Enough cold
air aloft pours in Sunday to suggest a little snow could mix in. The
colder air Sunday will come on drying northwest winds. With surface
temperatures well above freezing...kept it all rain at this point. A
large polar high pressure system begins to build in from the west
late Sunday and Monday.
High temperatures well into the 60s Friday and Saturday lower to the
mid 50s Sunday and around 50 on Monday. Lows in the upper 30s to mid
40s Friday through Sunday mornings lower to the 30s Monday morning.
&&
.AVIATION /21Z MONDAY THROUGH SATURDAY/...
Low pressure continues to track northeast along the coast and was
situated near the southeastern North Carolina coast at midday.
Patches of light rain covered the forecast area and were generally
moving to the north. A break in the rain is indicated for
southeast Virginia for the next few hours with mainly VFR
conditions present. Farther inland...widespread IFR ceilings were
observed over the Piedmont and east into south central Virginia
including the Tri-cities area. Have TEMPO group for IFR at RIC
for the first four hours of the TAF.
With moist low levels...expect widespread MVFR conditions by early
evening and models support IFR or LIFR ceilings in southeast
portions after Midnight. Conditions slowly improve mid morning
Tuesday as the low pulls off to the northeast.
OUTLOOK...Beginning Tuesday afternoon...most of the period will be
dry with high pressure dominating. A weak front/sfc trough crossing
the region will bring a period of BKN cloud cover and potentially a
few light showers late Wednesday into the Wednesday night. This will
affect mainly northern portions. Another round of showers is
possible late Saturday as a stronger cold front moves through.
&&
.MARINE...
Sca headlines remain in place tonight into Tue morng. Sfc low pres
just off the NC coast late this aftn will push northeastward tonight
and strengthen, with winds becoming nly at 15-20 kt with gusts to 25
kt over the Bay and Ocean late this evening/overnight. Seas up to 5
ft out 20 nm. As the low pushes ne towards New England Tue, winds
will relax over the local wtrs. The sca over the Bay ends at 7am and
over the Ocean at 1pm. Benign marine conditions then for Tue
night/Wed as high pressure builds in from the west. A cold front
crosses the area late Wed with at most marginal SCA conditions psbl
behind the front Wed night/Thu. High pressure then builds over the
waters for late Thu thru Fri.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...Small Craft Advisory until 7 AM EST Tuesday for ANZ630>632-634.
Small Craft Advisory until 1 PM EST Tuesday for ANZ650-652-654-
656-658.
&&
$$
SYNOPSIS...LKB
NEAR TERM...LKB/SAM
SHORT TERM...LKB/SAM
LONG TERM...LSA
AVIATION...LKB/LSA
MARINE...MAS
Area Forecast Discussion
National Weather Service State College PA
510 PM EST Mon Nov 14 2016
.SYNOPSIS...
A weak storm system will move up along the east coast tonight and
Tuesday. This will bring a chance of light showers to southeast
Pennsylvania. Another weak disturbance will bring a chance of
showers to NW Pennsylvania as well as a brief reinforcing shot of
cooler air Wednesday. Temperatures will moderate once again by the
end of the week as a ridge of high pressure returns to the eastern
US. Temperatures will be well above average by the end of the work
week.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Cloud cover has entered southern PA and radar shows precipitation
shield with light showers not too far south of there. HRRR runs
show precipitation decreasing in coverage and intensity as it
moves northward into drier air, but expect it to hold together
enough to bring some light showers to SE zones overnight. QPF
should be on the order of a quarter of an inch or less, but any
rain is welcome given how dry its been this fall. With milder
airmass and more cloud cover overnight temperatures will be a
little milder than last few nights.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
Low pressure system moves into New England with decreasing clouds
and pops west to east leading to a pleasant afternoon with
temperatures again several degrees over average. A shortwave in
westerly flow will approach NW CWA late Tuesday night with cloud
cover increasing as well as the chance of light showers towards
daybreak Wednesday.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
After the low lifts NE of the region Tue night, the long wave
trough will sharpen over the eastern CONUS through midweek with an
embedded shortwave bringing a chance of showers Wednesday along
with a brief reinforcing shot of cooler air.
The progressive pattern will result in a big ridge returning for
the end of the week along with moderating temperatures.
After a dry Thursday and a very mild Friday (with temperatures
climbing into the 60s), a new trough moving through the central
US that will push a cold front through the local area this
weekend. The models still disagree with the strength and timing of
the front and the amount of rain that will occur with it - though
timing of precip should be focused from late Sat into Sunday.
What seems more certain is that the weekend will end with a shot
of colder air (as 850MB temps drop some 15-20C) that will last at
least into early next week in brisk NW flow. This will also bring
mention of sct rain and snow showers to northern mtns and laurel
highlands as high temps fall back into the 30s and 40s.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
A weak low pressure system near Cape Hatteras will track northward
over the next 24 hours, bringing the chance of a few showers
across Eastern Pa late tonight and Tuesday. However, dry low level
air over the region should ensure a continuation of VFR conditions
across all of Central Pa through Tuesday evening.
Outlook...
Wed...Showers/reduced cigs possible KBFD/KJST.
Thu-Fri...No sig wx expected.
&&
.FIRE WEATHER...
Dry conditions this afternoon with RH values quite low below 30
percent across the area. However winds are expected to be mainly
under 10 mph.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Ross
NEAR TERM...Ross
SHORT TERM...Ross
LONG TERM...La Corte/RXR
AVIATION...Ross/Fitzgerald
FIRE WEATHER...
Area Forecast Discussion
National Weather Service Lincoln IL
259 PM CST Mon Nov 14 2016
.SHORT TERM...(This evening through Tuesday)
ISSUED AT 245 PM CST Mon Nov 14 2016
20z/2pm surface analysis shows a weak cold front extending from near
Madison, Wisconsin to just east of Kansas City, Missouri. The
airmass ahead of the boundary remains quite dry, although surface
dewpoints have risen slightly into the lower to middle 40s across
central Illinois this afternoon. As the front slowly edges
eastward, mid/high clouds will be on the increase late this
afternoon into the evening: however, a lack of deep-layer moisture
will prevent any precip development. The front will gradually make
its way to the Indiana border by 12z Tue. With dewpoints pooling in
the 40s along the boundary and mid/high clouds expected to
dissipate, patchy fog will likely develop overnight. HRRR has been
consistently showing fog developing across the eastern two-thirds of
the KILX CWA after 08z. Have therefore added patchy fog to the
forecast everywhere along/east of the Illinois River. This will not
be a good set-up for widespread or dense fog, so am only
anticipating minor visby reductions. Once any early morning fog
burns off, mostly sunny skies will prevail on Tuesday with afternoon
highs topping out in the upper 50s and lower 60s.
&&
.LONG TERM...(Tuesday night through Monday)
ISSUED AT 245 PM CST Mon Nov 14 2016
Unseasonably warm weather to be the main story through Friday as a
strong storm system tracks across the upper Midwest, with much
colder weather to follow for the rest of the forecast period.
Upper level ridging forecast to amplify over the central U.S. in
response to a powerful trof forecast to dig into the southern
Rockies on Thursday. This should result in an increasing southerly
flow over the Midwest late Wednesday and especially on Thursday
helping to pump afternoon temperatures well into the 70s. 12z models
very similar to the 00z solutions with the GFS the slowest to push
the cold front through our area Friday evening, while the ECMWF had
the boundary through southeast Illinois by mid-afternoon. Amplified
pattern over the lower 48 lends credence to the slower GFS solution
over the past few days so will continue to lean towards its forecast,
which will result in slower cold frontal passage late Friday. As a
result, it looks like a classic cool season severe weather threat
for parts of the Midwest Friday afternoon into the evening hours.
The shear profiles have never been an issue with this system, with
50-60 kts 0-6km bulk shear seen on just about any model you looked
at over the past 3-4 day , but due to the meager moisture proflies
depicted on the ECMWF, cape values have been low to non-existant.
May see some showers and storms enter our far western counties
Friday morning, but the main event, if there is going to be one,
will be in the afternoon and early evening hours as the front
sweeps across the area. The shower threat will begin to shift off
to our east late Friday night as the mid level dry slot tracks
across the forecast area.
Wrap around moisture and strong cold advection will be the main
weather story on Saturday with the more robust GFS suggesting some
showers affecting our northern counties, while the ECMWF shifts the
moisture further northeast away from our area on Saturday. Model
consensus suggests the better threat for the light showers will
be to our north and east on Saturday, so for now, will keep the
area dry. However, gusty northwest winds and low level cold
advection should keep afternoon temperatures in the 40s on
Saturday with night-time lows dropping into the middle 20s. A
chilly weather pattern looks to hold through the remainder of
this forecast period before we see a warming trend set up for the
Midwest a couple of days before Thanksgiving.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1141 AM CST Mon Nov 14 2016
No aviation forecast concerns through the afternoon...as
southwesterly winds of 8-12kt continue and a gradual increase in
mid/high clouds is noted. Latest Rapid Refresh forecast
soundings suggest a period of BKN ceilings at around 5000ft may
develop late this afternoon into the early evening at the I-72
terminals, with mostly clear skies further northwest at KPIA and
KBMI. A weak cold front will push into the area from the west
later this evening, shunting these clouds further east as the
night progresses. With clearing skies and winds veering to W/NW
and decreasing to 5kt or less overnight, the main question will be
if any fog will develop. Model solutions vary on this, with the
NAM suggesting fog/low ceilings by early Tuesday morning. Think
the NAM may be too moist with its boundary layer, so have trended
away from its solution and more toward the GFS/Rapid Refresh which
only hint at some patchy/light fog. Have therefore mentioned 4-5
mile visbys between 07z and 15z at all terminals. Once any early
morning fog dissipates, clear skies and light NW winds will
prevail through 18z Tue.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Smith
AVIATION...Barnes
Area Forecast Discussion
National Weather Service Mount Holly NJ
414 PM EST Mon Nov 14 2016
.SYNOPSIS...
Low pressure off the North Carolina coast will pass east of the New
Jersey coast during midday Tuesday. A weak cold frontal passage is
expected late Wednesday, followed immediately by high pressure
building over the region through the remainder of the work week. A
stronger cold front and low pressure system will affect the region
later this weekend.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
An area of low pressure currently off the North Carolina coast will
continue to move northward through tonight and should reach the
offshore waters of Delware by daybreak Tuesday. Low cloud cover will
be on the increase well ahead of the system as mid/high level clouds
have already made their way across the area. A strong short
wave/vorticity impulse will round the base of the mid-level trough to
our west and make its way into our area overnight and through
daybreak. The enhanced lift along with an increase in low-mid level
moisture will allow rain to spread across the area overnight into
Tuesday morning. It looks like the strongest lift may stay closer
the low along the central/southern Delmarva and southern/eastern New
Jersey. Some periods of moderate rainfall will likely occur as the
low gets closer around daybreak. There could be some rain west of
these areas, but the heaviest rainfall we expect across the eastern
half of the area. There may also be an occasional lightning strike
toward the coast as some very weak instability is forecast offshore,
but we will not include in the forecast at this time.
It was looking earlier that there may be a possibility of some
freezing rain across the far north. However, the majority of the
latest guidance does not bring the temperatures down below freezing,
with the exception of MOSGUIDE and MAV MOS. All other guidance,
include the HRRR and RUC keep temperatures above freezing. As cloud
cover increases this evening and overnight, this should help limit
rapid radiational cooling. However, one concern we have is the
dewpoints are quite low across the northern half of the area. So
until they increase, there will remain the potential for
temperatures to cool tonight. In the end however, we did not include
freezing rain in the forecast nor issued any advisory, as there may
not be any precipitation that far north anyway through daybreak.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
Precipitation should be ongoing across the eastern half of the area
at the start of Tuesday morning as the low pressure system continues
to lift northward offshore of the New Jersey coast. The low will
continue to lift to our northeast by late afternoon, as will the
precipitation. The rainfall will likely end across the southern
areas during the morning hours, but could hang on across the
northern areas as the rain could pivot back westward as the low
moves northward. All precipitation should be exiting the area by the
late afternoon hours. Although rainfall will end across the southern
areas, clouds cold linger through the day, which will help suppress
temperatures from rising much during the day.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
500 MB: A trough along the east coast coast Tuesday night and
Wednesday will be replaced by an anomalously warm and strong
ridge Friday. An amplifying trough is expected to replace the
ridge on Sunday.
Temperatures: The first 13 days of November have been warmer and
drier than normal with temperatures averaging 1 to 3 degrees above
normal. Calendar day averages will be about 4 degrees above normal
Wednesday, and 5 to 10 degrees above normal Thursday through Saturday,
cooling several degrees below normal next Monday. (rainfall so
far this month has averaged 0.8 to 1.5 inches below normal)
Forecast basis: Unless otherwise noted, a 50 50 blend of the 12z/14
GFS/NAM MOS guidance Tuesday night- Wednesday night, thereafter the
12z/14 GFS MEXMOS Thursday and Thursday night, and then the 15z/14
WPC guidance Friday-Monday, at times blended with the 12z/14 GFS
MEXMOS guidance through Sunday.
The dailies...
Tuesday night...Clearing after any sprinkles end during the evening.
Wednesday...A weakening cold front is expected late in the day as an
amplified negative tilt short wave burrows southeastward toward the
Delmarva. Considerable cloudiness with scattered afternoon and
evening showers with slight chance of an isolated thunderstorm
near the 500mb vort max as it passes across the Philly area through
NJ. TT increase to between 52-56C so its not impossible to think
about small hail (no modeled ML Cape). For now, due to multi model
passiveness about any showers with this vort max, have not put thunder
in the grid. Light west wind becoming northwest at night.
Thursday and Friday...Surface high settles in, and a high
amplitude upper level ridge builds over the region by Friday,
leading to a warming trend and beautiful mid November weather.
Light mostly west wind. May have some patchy dense fog late each
night? The fogger tool looked like a nice fit for Thu night and I
could see much more fog Fri night than currently in the fcst.
Saturday through Sunday...Next low is expected to cross the Great
Lakes region through this time. Additionally, an off shore low is
expected to intensify. As such, the upper level ridge over our
region should rapidly weaken (though exactly how quickly this will
occur is uncertain). A cold front associated with the Great Lakes
low could arrive in our region as early as Saturday, but more
likely Saturday night into Sunday. Precipitation and a big cool
down is likely with the front. There may be some backside snow
accums in the Poconos. Additionally, windy conditions are expected
after the frontal passage on Sunday. The HWO has a northwest gale
Sunday for the marine area and our public forecast may be a bit
underdone, especially NJ and DE. The argument against a strongly
windy day Sunday on the land is that the air temps will be at
least 5 degrees lower than the waters temps where greater low lvl
instability will exists.
Monday...Blustery and colder than normal with a possible sprinkle or
flurry except only flurries in the Poconos. Northwest gusty 30-40
mph.
&&
.AVIATION /21Z MONDAY THROUGH SATURDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.
VFR conditions will continue across the TAF sites through the
remainder of the afternoon and into the early evening. However,
lower clouds will be on the increase through the night and into
Tuesday as an area of low pressure moves northward offshore of the
east coast tonight into Tuesday. MVFR conditions are expected across
the southern areas by midnight local as rainfall moves into the
area, then spread north and westward through the night and into
daybreak. There is a possibility for IFR conditions overnight into
the morning hours Tuesday for much of the area, but we think the
best possibility is across the the eastern half of the area, which
would affect ACY/MIV/TTN. The remainder of the area is forecast to
lower to MVFR, with ILG/PHL/PNE having the lowest MVFR conditions.
The rainfall is expected to come to an end from south to north
during the day. Although the rain is expected to end through the
day, the clouds will likely linger into the afternoon, and VFR
conditions may not return until late in the day.
Winds vary from southwest to west from site to site this afternoon
around 5-8 knots. Winds will likely become even more variable this
evening as the lighten up further. However, as the low pressure
moves northward overnight, a northeasterly flow is expected to
develop across the area. Winds are then expected to swing toward the
northwest by daybreak and through the day Tuesday. Winds may at
times become gusty in the mid to upper teens farther away from the
coast around daybreak and into Tuesday.
Outlook...
Tuesday night...Any leftover MVFR conditions will give way to VFR
clear skies during the night with a northwest wind. Confidence: well
above average.
Wednesday...VFR cigs may VERY briefly degrade to MVFR conditions
in an afternoon or evening shower. West wind during the day
becoming northwest at night. Confidence: average.
Thursday through Friday...mostly VFR conditions with a west to
northwest wind. Confidence: well above average.
Saturday...VFR cigs probably developing. Rain possible at night.
Easterly flow. Confidence: average.
&&
.MARINE...
A Small Craft Advisory will remain in place for the Atlantic
Ocean coastal waters as winds are expected to increase as an area
of low pressure lifts northward and passes across the coastal
waters tonight into Tuesday. Winds are expected to gust around 25
knots, and seas will also build during the day Tuesday as well to
4-6 feet.
Outlook...
Tuesday night and Wednesday night...No marine headline anticipated
except the dwindling seas driven hazard headline across portions
of the northern and central NJ coast Tuesday evening. Confidence:
above average.
Thursday through Friday...No marine headline anticipated with a
general northwest to west flow. Confidence: well above average.
Saturday...Easterly flow develops and may require an sca headline at
night followed by a potential northwest gale sometime Sunday.
Confidence: above average.
&&
.TIDES/COASTAL FLOODING...
With the supermoon tonight, astronomical tides are running high
already. Guidance indicates that we could reach the minor flood
level Tuesday morning, but not the minor flood level required to
issue a Coastal Flood Advisory. So we will not issue any advisories
and will monitor the latest model guidance to see if they forecast a
stronger surge in the future. The high tide of concern would the be
Tuesday morning tide that occurs between 8 and 9 am along the ocean
front.
&&
.EQUIPMENT...
There was a significant NWS communications issue earlier this
afternoon that affected the internal posting of TAF products as
well as the ECMWF. This comms problem is reported to be fixed and
hopefully had little impact externally.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory from 1 AM to 3 PM EST Tuesday for
ANZ452>455.
Small Craft Advisory from 7 AM to 11 PM EST Tuesday for ANZ450-
451.
&&
$$
Synopsis...Drag
Near Term...Robertson
Short Term...Robertson
Long Term...Drag 414
Aviation...Drag/Robertson
Marine...Drag/Robertson
Tides/Coastal Flooding...
Equipment...414
Area Forecast Discussion
National Weather Service Raleigh NC
325 PM EST Mon Nov 14 2016
.SYNOPSIS...
An upper level low and an associated area of low pressure will
lift northeast away from the area tonight, followed by another
upper level trough on Tuesday. An upper level ridge then will
build east over the region for the latter half of the work week.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 300 PM Monday...
Shearing upper low over southern VA will get a kick northward
tonight by another shortwave approaching the Tenn Valley.
Meanwhile, a surface low east of Morehead City will continue up
the coast, with the the associated deformation band that has been
parked over the north/central Piedmont lifting north as well.
Recent HRRR runs suggest the last of the light rain will be north
of the VA border by 00Z this evening. Lingering moisture, of highly
variable character and depth, is forecast to scour tonight, though
the westerly flow that will advect drier air in is weak. Models are
adamant that skies will clear from west to east, however, which
could lead to some fog immediately behind the clearing. SREF probs
and the HRRR indicate fog potential pretty much anywhere, so fog has
been added to the overnight forecast.
Lows 38-44
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
As of 300 PM Monday...
Cyclonic flow will continue aloft as yet another shortwave dives
out of the upper Midwest and across the area, carving out a deeper
longwave trough axis that will push east of central NC by
Wednesday. Forecast soundings look too dry to wring out any precip
some previous GFS/ECMWF runs showing such. Have used low level
thicknesses to get forecast highs given little thermal advection,
which are on the warmer side of statistical guidance, 64-67. Weak
winds and mostly clear skies will allow for strong radiational for
at least the first half of the night, with a light wind after
midnight as the the upper trough moves overhead and the MSLP
gradient tightens a little. Lows should reach the upper 30s to lower
40s.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
As of 325 PM Monday...
Fairly tranquil weather pattern expected to persist across central
NC through the extended period. Temperatures initially will average
close to normal then climb to above normal levels Friday and
possibly Saturday before a much colder air mass overspreads the
region by Sunday.
An upper level trough along the eastern seaboard Wednesday will
gradually lift/move east, allowing an upper level ridge anchored
over the Gulf of Mexico to extend nwd into the Carolinas Thursday
and Friday. This weather system will usher in a warmer air mass,
leading to afternoon temperatures well into the 60s to around 70 on
Friday.
Forecast becomes more uncertain during the weekend as model timing
differences very apparent with the ECMWF as much as 12-18 hours
faster compared to the GFS. Both models depict a strong/deep upper
level low over the western Great Lakes early Saturday. This system
will likely grab the weather headlines the later half of the week as
it has the potential to cause the first winter storm of the season
over much of the northern Plains and upper Midwest. If ECMWF
verifies, expect frontal passage early in the day Saturday. If GFS
is more correct, frontal passage will not occur until late Saturday
or Saturday night. Even if the ECMWF is more correct, cold air
advection will likely be offset by downslope component of low level
wind. For now will favor the slower timing, and project afternoon
temps near 70-lower 70s over the se half of the forecast area.
Colder air should overspread the region by Sunday, leading to
afternoon high temps as much as 15-18 degrees cooler compared to
Saturday afternoon. The cool air will linger into Monday.
Atmosphere projected to remain quite dry for this time of year.
Inspite of the strong front, moisture very limited so expecting
nothing more than a band of cloudiness with the front. If the
dynamics aloft swing far enough south on Sunday, potential for an
isolated shower or two to occur during the afternoon-early evening
hours. Also, potential for windy conditions behind the front Sunday.
If this materializes and the air mass dries out even further,
yielding minimum RH values in the 20s, could see an increased fire
danger threat across central NC.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
As of 105 PM Monday...
A band of rain associated with an upper low shearing off to the
north and a coastal east of Morehead City continue to result in
MVFR and IFR ceilings between RDU and GSO. On either side of this
band, VFR conditions have developed. There should be a weakening
trend in the precip through this afternoon as the band pivots off
to the north with the departing surface low. Lingering low-level
moisture will continue the threat of MVFR or IFR through this
evening, however, with weak westerly flow only slowly bring drier
air across the area tonight. Confidence isn`t terribly high in the
timing, but GSO/INT should be VFR by 03Z. Ceilings will scatter at
RDU/RWI/FAY by 06-09z, but this may also lead to a period of IFR or
LIFR vsbys by 12Z. VFR should return by 14Z and continue through the
day on Tuesday.
Outlook:
Dry VFR conditions should through the remainder of the work week.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...SMITH
LONG TERM...WSS
AVIATION...SMITH