Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/21/16
Area Forecast Discussion
National Weather Service Albany NY
1032 PM EST Sun Nov 20 2016
.SYNOPSIS...
Low pressure just north of New England will remain nearly
stationary through Monday, then slowly move east to Maine and then
Newfoundland on Tuesday. A northwesterly flow of cold and moist
air will bring cold weather and areas of snow to the region. The
highest snowfall accumulations are forecast for the hill towns and
mountains and in persistent lake effect snow bands.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
A Lake Effect Snow Warning is in effect to Monday evening for
Herkimer and Hamilton Counties. A Lake Effect Snow Advisory is in
effect for Schoharie, Fulton, Montgomery and Warren Counties for
the same time period. A Winter Storm Warning is in effect for The
southern Green Mountains of Vermont...the northern and central
Taconics...Helderbergs and central Catskills in New York and the
Berkshires in Massachusetts. Winter Weather Advisory continues for
the southeast Catskills and western Schenectady County and eastern
Dutchess County, and has been expanded to cover Litchfield County,
CT.
A Wind Advisory is in effect for all of eastern New York and
adjacent western New England through Monday afternoon.
As of 1032 PM...expanded winter weather advisory for snow and
blowing snow to Litchfield County, Ct based on some localized
amounts of 9-13 inches. Some areas have had very little so issued
advisory.
Previous...
As of 949 PM...Update to account for radar trends and adjust
diurnal temperature curve down some as temps have fallen a little
faster than forecast. Largest area of steady snow extends up and
down the Hudson River Valley east to the Taconics, southern Green
Mountains, Berkshires and Litchfield Hills. Latest HRRR seems to
be getting a handle on this and shows this area slowly moving east
but continuing overnight, while lake bands continue over the
northwestern part of the forecast area into the southern
Adirondacks, western Mohawk Valley and Eastern Catskills. With
the combination of wind and snow, a wild and wooly night,
especially for November.
Lows tonight will range from the upper teens to lower 20s
northwest to the upper 20s to around 30 southeast. Winds will
continue to be an issue with west to northwest winds 15 to 25 mph
with gusts up to 50 mph continuing. This is the reason why a wind
advisory has been issued for the entire region.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/...
By the time the snow tapers off Monday evening, snowfall amounts
across the Lake Effect Snow Warning and Winter Storm Warning area
are expected to be 6 to 14 inches with locally higher amounts
especially at elevations above 1000 feet. The Lake Effect Snow
Advisory area and Winter Weather Advisory areas are expected to
receive 4 to 8 inches with a few higher amounts. In the valleys
expect generally 1 to 4 inches of snow accumulation with the
exception of the mid Hudson Valley where only a dusting to around
an inch is expected. Highs on Monday are expected to be in the
mid 20s to around 40.
On Monday night...The low pressure system is expected to track
far enough east and the low level flow to weaken just a bit but
still breezy and shifting more northwest. So, some gradual
improvement to sky conditions, especially in valleys, and coverage
of snow shower activity should gradually decrease. Lows Monday
night are expected to be in the 20s with some upper teens possible
across the northwest Adirondacks.
On Tuesday...Another cold and chilly day is in store with just
some linger snow showers across extreme northwest portions of the
area. Highs will be in the upper 20s to lower 40s.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
This will be an unsettled period...with the likelihood of rain or
snow for most of it. But we will begin with mostly dry conditions
except for the western Adirondacks...which may receive some snow
showers in response to a weak surface trof passing through the area.
A system developing off the Colorado Rockies will track northeast to
the Great Lakes region through Wednesday night...and east across New
York state and southern New England through Thanksgiving night. This
will bring us a good chance of snow...especially during the day on
Thanksgiving Day. Strong overrunning to the north of a warm front
well south of Long Island will probably enable a transition over
to rain during the late afternoon at many locations outside of the
Adirondacks and Greens.
Behind the system Thursday night and Friday...colder air will turn
the rain over to showers with a mix over back to snow showers at
most locations. A clipper system will follow right along...keeping
the forecast area in a chance for snow showers...which will be
most likely Friday night during which time this clipper will track
through New York and New England. Snow and rain showers will
likely linger into Saturday. High pressure will probably provide
us with one more good day on Sunday...with just some snow showers
possible in the high peaks of the Adirondacks and Greens.
Daytime high temperatures from around 30 degrees to the mid or upper
40s will be common during this period. Lows Tuesday night in the
teens and 20s...will be in the 20s and lower 30s Wednesday
night...and from the upper 20s to mid 30s Thursday and Friday
nights. Saturday night lows will range from the lower 20s to lower
30s.
&&
.AVIATION /04Z MONDAY THROUGH FRIDAY/...
Low pressure just north of New England will remain nearly
stationary through Monday, then slowly move east to Maine and then
Newfoundland on Tuesday. A northwesterly flow of cold and moist
air will bring cold weather and areas of snow to the region. The
highest snowfall accumulations are forecast for the hill towns and
mountains and in persistent lake effect snow bands.
Mainly MVFR conditions are expected at KALB and KGFL TAF sites,
although a few periods of IFR could occur in snow, especially
tonight.
For KPSF, Generally IFR/LIFR conditions are expected through late
tonight. Some slight improvement is possible by later Monday
morning, as snow showers become more scattered and focused into
bands. Mainly MVFR conditions are expected Monday after 15Z,
although can not rule out occasional IFR.
At KPOU, mainly VFR conditions are expected through Monday, with
occasional flurries possible. However, some snow showers could
occasionally produce MVFR conditions.
West/northwest winds will reach 15-20 KT with gusts of 30-35 KT
and continue tonight into Monday morning.
Outlook...
Monday Night: No Operational Impact. NO SIG WX.
Tuesday: No Operational Impact. NO SIG WX.
Tuesday Night: Moderate Operational Impact. Chance of SN...FZRA...SLEET.
Wednesday: Moderate Operational Impact. Chance of SHRA...SHSN...SN.
Wednesday Night: Moderate Operational Impact. Scattered SHRA...SHSN.
Thanksgiving Day: Moderate Operational Impact. Scattered SHRA.
Thursday Night: Moderate Operational Impact. Scattered SHRA...SHSN.
Friday: Moderate Operational Impact. Scattered SHRA...SHSN.
&&
.FIRE WEATHER...
Low pressure tracking through eastern and northern New England
will slowly exit into eastern Canada through Tuesday bringing much
colder weather and snow to the area. The highest snowfall
accumulations are forecasted for the hill towns and mountains.
&&
.HYDROLOGY...
Snow is in the forecast with accumulations occurring across the
much of the area with the highest amounts across the higher
terrain over the weekend. Overall, liquid equivalent amounts
for the remainder of the storm through Monday are expected to
range from one tenth of an inch southeast to over half an inch
across the northwest portion of the area. Additional snowfall
amounts are expected to range from generally 1 to 4 in the valleys
except less than an inch in the mid Hudson Valley. Higher terrain
will have an additional 4 to 8 inches with the highest amounts
across the northwestern Adirondacks. More precipitation is
expected during the mid week period heading into Thanksgiving Day.
For details on specific area rivers and lakes, including observed
and forecast river stages and lake elevations, please visit the
Advanced Hydrologic Prediction Service /AHPS/ graphs on our
website.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...Winter Weather Advisory until 7 PM EST Monday for CTZ001.
Wind Advisory until 6 PM EST Monday for CTZ001-013.
NY...Winter Weather Advisory until 7 PM EST Monday for NYZ048-063-
066.
Wind Advisory until 6 PM EST Monday for NYZ032-033-038>043-
047>054-058>061-063>066-082>084.
Winter Storm Warning until 7 PM EST Monday for NYZ051-054-058-
061.
Lake Effect Snow Advisory until 7 PM EST Monday for NYZ039-040-
042-047-082.
Lake Effect Snow Warning until 7 PM EST Monday for NYZ032-033-
038.
MA...Wind Advisory until 6 PM EST Monday for MAZ001-025.
Winter Storm Warning until 7 PM EST Monday for MAZ001-025.
VT...Wind Advisory until 6 PM EST Monday for VTZ013>015.
Winter Storm Warning until 7 PM EST Monday for VTZ013-014.
&&
$$
SYNOPSIS...11/NAS
NEAR TERM...SND/11
SHORT TERM...11
LONG TERM...ELH
AVIATION...KL/JPV
FIRE WEATHER...11/NAS
HYDROLOGY...11/NAS
Area Forecast Discussion
National Weather Service Bismarck ND
914 PM CST Sun Nov 20 2016
.UPDATE...
Issued at 910 PM CST Sun Nov 20 2016
Continue to have doubts about the likelihood and extent of the
fog in the forecast tonight as the HRRR shows very little.
Decreased the fog area and trimmed to patchy from areas. Also
trimmed the cloud cover using the CONSALL guidance which seemed
ok.
UPDATE Issued at 638 PM CST Sun Nov 20 2016
Latest HRRR runs have played down the stratus and fog tonight
across central North Dakota. Not sure if this is the right trend
yet but will delay the clouds and fog until late tonight. With
that in mind also lowered min temperatures into the upper teens
across portions of south central North Dakota.
&&
.SHORT TERM...(This evening through Monday)
Issued at 245 PM CST Sun Nov 20 2016
The main concern tonight into Monday will be the possibility of
another round of stratus and fog. Early afternoon visible
satellite imagery shows a small patch of stratus remaining across
the northwest part of the state, otherwise skies were mostly
sunny. Short term models, and in particular the HRRR suggest
another round of stratus and fog developing tonight. The central
part of the state appears to be the favored location for the lower
visibilities and have gone with areas of fog in that region. Have
some concern the fog could become dense and widespread enough to
warrant an advisory if the HRRR output is on target.
.LONG TERM...(Monday night through Sunday)
Issued at 245 PM CST Sun Nov 20 2016
Attention Monday night into Tuesday shifts to the next in a series
of upper waves that are expected to move across the region
through the week. One of the initial concerns for Monday night
into Tuesday morning is the possibility of a wintry mix,
especially as the precipitation begins. Thermal profiles still
suggest warm enough air aloft to support a period of light
freezing rain before changing to snow. Another complicating factor is
that forecast soundings still also show a dry layer with
potential cooling to the wet-bulb in some locations. Will carry a
mix in the grids, and also mention it in the Hazardous Weather
Outlook this afternoon. Potential snow totals still appear light
with snow ratios remaining low through Tuesday.
The remainder of the week with have periodic chances of mainly light
snow in a fairly progressive pattern. Precipitation amounts with
any of the systems still appears fairly light.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 638 PM CST Sun Nov 20 2016
Low pressure across central Montana will move slowly east. Patchy
fog is expected to form over central North Dakota after 06z with
MVFR conditions possible at KMOT-KBIS-KJMS between 06-15z.
Otherwise VFR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...CK
LONG TERM...CK
AVIATION...WAA
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
356 PM PST Sun Nov 20 2016
.SYNOPSIS...
Showers will continue through early Monday afternoon, before a brief
period of dry weather develops, as a short-wave ridge temporarily
builds across the area. However, another storm system will be on its
heels and start to affect northern California by Tuesday morning.
Showers will develop, with a few coastal thunderstorms possible
during the afternoon and evening ahead of a cold front, with rain
developing behind it, which will persist through the weekend.
&&
.DISCUSSION...
After tonight`s showers, a brief dry period will commence tomorrow
afternoon, as an upper-level short-wave ridge builds across the
region. However, this will be short-lived, as another trough will
approach the region on Tuesday. Instability will be stronger with
this system compared to its predecessor we`ve dealt with over the
past couple of days, as mid-level lapse rates are forecast to be
near/over 8 deg. C/km, with total totals soaring above 60, negative
lifted indices, and sufficient MUCAPE developing ahead of a cold
front. With all this in mind, thunder was added to the marine and
coastal zones. My gut feeling is we`ll eventually need to spread
this thunder mention inland across all of northwestern California,
as the models seem too low with the MUCAPE further inland given the
parameters described above.
As the front crosses the region and the trough moves overhead,
rainfall will become widespread and increase in intensity. Snow
levels will will also drop to around 3500 feet. As it stands right
now, none of the major highways look to be impacted, except Scott
Mountain Pass along highway 3. If these levels drop more though,
this could be a different story. Otherwise, rain will persist through
the weekend. /PD
&&
.AVIATION...
The threat of thunder has waned, and showers continue to
decrease in intensity and coverage. However, both the NAM and the
HRRR indicate a bit of an uptick in shower coverage late tonight.
Clouds are expected to gradually thin and lift during the day Monday
with some lingering light coastal showers possible early in the
morning. Wind gustiness has diminished and sustained speeds along
the Redwood Coast are dropping below 12 knots. The combination of
lighter winds, breaks in the clouds, and ground moisture may lead to
patchy ground fog overnight, but uncertainty is high that
visibilities will drop below MVFR criteria. /SEC
&&
.MARINE...
The sea state was slightly higher than forecasted today
with the buoys finally showing a slight downward trend. Current buoy
readings are showing 11 to 13 ft waves at 13 to 14 seconds. In
response to this and looking at the new model data we have extended
the small craft advisories until 17Z Monday morning. The rest of
Monday will be free of any special marine products as high pressure
briefly takes control of the forecast, but these conditions will be
short lived. Come Tuesday, we`ll see the start of a parade of storms
which will bring an increase in winds and building swell to our
waters. Current thinking is that we`ll likely have to hoist small
craft advisories for at least the northern waters. For the extended
forecast, the models fall out of phase with each other which makes
forecasting the arrival of the future storms and swells difficult.
We are expecting to see brief periods of increasing winds and large
seas as a result of the various storms passing through. /KAR
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...None.
NORTHWEST CALIFORNIA COASTAL WATERS...Small Craft Advisory until 9 AM PST Monday for PZZ410-450-455-
470-475.
&&
$$
Visit us at http://www.weather.gov/eureka
Follow us on Facebook and Twitter at:
http://www.facebook.com/NWSEureka
http://www.twitter.com/nwseureka
For forecast zone information
see the forecast zone map online:
http://www.weather.gov/eureka/zonemap.png
Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
325 PM PST Sun Nov 20 2016
...Updated Aviation section...
.SYNOPSIS...
A storm system will impact the central California interior on
Sunday, bringing the region a chance of rain and mountain snow.
Another system may impact northern parts of the area by mid-week
on Wednesday.
&&
.DISCUSSION...
145 pm PST radar shows a line of precipitation extending along a
cold front from Yosemite National Park south through San Luis
Obispo. Up to a third of an inch of rain has already been observed
in the parts of Merced County. The front will continue to push
east through central California during the afternoon and evening
hours on Sunday, bringing along with it the increased chance of
precipitation as moisture advects from the south. HRRR and high-
res WRF models advertise the rain approaching Fresno by mid-
afternoon to early evening. As the front pushes through, we`ll see
snow levels fall to around 7,000 feet - possibly as low as 6,500
feet - near Yosemite National Park where a Winter Weather
Advisory is in effect through 10 pm PST Sunday.
Showers will linger over the area Monday morning and afternoon,
especially for locations in the mountains, foothills and southern
San Joaquin Valley. While the upper low continues to push into the
North American continent, fog will become a concern in the San
Joaquin Valley for the Tuesday morning commute as a ridge builds
over the West Coast. Right now confidence is medium for fog
development, but its intensity and coverage is still unknown.
Tuesday`s ridge will be short-lived as another system approaches
the West Coast on Wednesday. This system still has some unknowns
with the timing and trajectory. 12Z GFS and ECMWF suggest
precipitation for the northern half of the CWA (Fresno County
northward) with the best potential in Yosemite National Park.
Thanksgiving Day looks to be mainly dry for holiday travelers
across the central California interior, but another storm system
will begin to aim on northern California late Thursday.
Precipitation chances for our area will begin to increase by the
Friday/Saturday time frame. Confidence for the timing and
placement of this storm system is low. Model uncertainty continues
to grow beyond Saturday, but it does appear the pattern will
remain unsettled for the West Coast into the end of November.
.AVIATION...
In the southern Sierra...IFR conditions can be expected in Yosemite
National Park with IFR conditions spreading southward to Kings
Canyon National Park by 03z Monday. Mountain obscurations in heavier
precipitation.
In the Sierra foothills...MVFR conditions in Mariposa and Madera
County with MVFR conditions spreading southward into Tulare County
by 03z Monday.
Areas of MVFR ceilings can be expected along the north facing slopes
of the Tehachapi mountains between 06z and 18z Monday.
In the San Joaquin Valley...areas of MVFR ceilings are possible
north of Kern County through 18z Monday with local IFR ceilings in
Merced County between 12z and 16z Monday.
&&
.AIR QUALITY ISSUES...
None.
&&
.CERTAINTY...
The level of certainty for days 1 and 2 is medium.
The level of certainty for days 3 through 7 is medium.
Certainty levels include low...medium...and high. Please visit
www.weather.gov/hnx/certainty.php for additional information
an/or to provide feedback.
&&
.HNX Watches/Warnings/Advisories...
Winter Weather Advisory until 10 PM PST this evening ABOVE 7000
FEET FOR THE CAZ096.
&&
$$
public...Rowe
avn/fw...Durfee
synopsis...Rowe
weather.gov/hanford
Area Forecast Discussion
National Weather Service Marquette MI
619 PM EST Sun Nov 20 2016
.SHORT TERM...(This evening through Monday)
Issued at 341 PM EST SUN NOV 20 2016
Water vapor imagery and RAP analysis show a deep, negatively tilted
mid/upper level trof over the ne CONUS with a broad ridge from the
Rockies into the Plains. LES into the n central fcst area held on
with more intensity than expected last night into the morning
despite the overall hostile large scale environment of rather strong
qvector divergence/subsidence in addition to low inversion/dry air
mass per upstream observed soundings. Finally, late morning into
this aftn, LES has really diminished. Drying of the air mass is also
evident on vis satellite imagery with cloud streamers initiating
farther out over the water from the upstream shore of the lake as
well as clouds dissipating northward from northern WI.
Upstream sfc ridge axis over ne MN/western WI will only drift to far
western Lake Superior tonight and only reach far western Upper MI by
late Mon aftn. As a result, northerly flow across Lake Superior will
prevail tonight/Mon, except over far western Upper MI which will see
low-level winds veer more to the ne or e during the day Mon. With
850mb temps tonight only slowly rising to around -7C w and -11C e by
12z Mon, stratocu will probably dominate much of the area tonight,
and light LES/flurries will continue into the n central and eastern
fcst area. Clouds will keep temps from crashing over the w which
will be under light winds closer to the ridge. There is some erosion
of clouds from the s over northern WI into s central Upper MI
currently, and this clearing may sneak farther n and w over the next
hr or two into Iron and perhaps Gogebic counties as weak daytime
heating works to mix out moisture a bit. However, with nocturnal
cooling, lake effect clouds should expand again during the night
under inversion, especially away from the far s central, though
increasing anticyclonic flow may work against the cloud expansion.
Even if low clouds don`t expand, considerable mid/high clouds are
moving across MN toward western Upper MI. In the end, min temps
should range from around 10F interior w to the mid/upper 20s along
Lake Superior central and e. If clouds manage to scatter out for a
time over the w, temps could quickly plunge toward 0F.
Any lingering light LES/flurries will end over the n central and e
by early Mon aftn as air mass continues to moderate and dry. Expect
a gradual decrease in clouds with s central and w having best chc of
becoming mostly sunny during the day. Much of the day will probably
be mostly cloudy n central and e. High temps should be mostly in the
upper 20s/lower 30s.
.LONG TERM...(Monday night through Sunday)
Issued at 245 PM EST SUN NOV 20 2016
Main significant weather in the long term is mid-week with potential
for advisory (or possibly low end warning) level snow.
An upper trough is modeled to move through the area mid-week,
bringing a roughly 1010mb SFC low from northern IL/southern WI
through central lower MI Wed and Wed night. Widespread precip is
modeled to move into the W or SW late Wednesday, and the bulk will
move out Wed night. Models are in good agreement overall, but vary
on QPF. The GFS and GEM at up to 0.70" while the ECMWF only has up
to around 0.40". Most of the precip falls as snow, with the
exception possibly of the south-central where a transition to rain
is more likely. If the event plays out as currently modeled, winter
weather advisories would be needed over at least a portion of the
area, with potential for some warning amounts if the GFS/GEM amounts
verify. For now, given the inherent uncertainty at that time frame
with this type of system, will continue to mention in the HWO.
Definitely will have to keep a close eye on the system given the
high-impact travel day.
Lighter snow is possible Thursday into the weekend, but not looking
at any significant amounts right now.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 619 PM EST SUN NOV 20 2016
Chilly air mass over Lake Superior along with northerly winds will
result in bkn-ovc MVFR stratocu prevailing thru this fcst period at
KIWD/KCMX/KSAW. However, with high pres ridge settling over western
Lake Superior tonight/Mon, increasing anticyclonic flow may cause
stratocu to sct out at KIWD Mon morning and at KCMX and KSAW near
the end of the fcst period.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 341 PM EST SUN NOV 20 2016
High pres ridge that will settle over western Lake Superior tonight
will very slowly shift e, reaching eastern Lake Superior Tue
morning. This will lead to light winds, mostly under 15kt over the
western part of the lake thru Mon night. Over eastern Lake Superior,
winds will generally remain in the 20-30kt range tonight, slowly
diminish to under 20kt by late Mon aftn, then to under 15kt for Mon
night/Tue. The ridge will then shift e more quickly as a low pres
system emerging over the Plains early Tue tracks ene into the
western Great Lakes by Wed evening. As a result, winds will increase
to 20-25kt across much of the lake Tue night into Wed with the
strongest winds occurring over central and eastern Lake Superior.
Winds will diminish to under 15kt for Thu/Fri as the pres gradient
across the area becomes weak.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...Titus
AVIATION...07
MARINE...Rolfson
Area Forecast Discussion
National Weather Service Tucson AZ
855 PM MST Sun Nov 20 2016
.SYNOPSIS...An approaching weather system will increase moisture
across Arizona tonight. Showers will expand east across the area
tonight into Monday morning. Showers will end from the west Monday
night with a few lingering showers east of Tucson on Tuesday. Much
cooler Monday then seasonal temperatures and dry Tuesday into next
weekend.
&&
.DISCUSSION...Plenty of energy in the base of the trough as it
shifts onshore into southern California tonight. We`re still in
the process of moistening from mid levels down with virga, or no
more than isolated sprinkles across most of SE AZ this evening.
Light showers with a little deeper moisture in western Pima
county. We slowed the onset of light precip in the forecast down a
tad based on current trends and latest HRRR trends. We should
still see an increase after midnight.
Water vapor imagery showing a dry slot wrapping into the base of
the trough in between the current moisture increase from the south
and the main energy in the base of the trough. We`ll probably see
some filling in of clouds and showers due to orographic effects,
but don`t be surprised to see a significant break this far south
by the mid morning hours. It`s unclear if the resulting surface
heating would be enough to lift a few thunderstorms in the early
afternoon Monday.
&&
.AVIATION...Valid through 22/06Z.
Thick patches of mid-high clouds will gradually lower overnight as
-SHRA increase from the west ahead of a trough approaching
southern California. Expect ceilings in the early morning hours
around 5-8k ft AGL. Can`t rule out localized MVFR conditions
after 21/07z, especially near the mountains. A slight chance of
embedded thunderstorms with the showers Monday before partial
clearing from the west by Monday evening. Sfc wind generally SWLY
less than 12 kts, increasing after 21/20z.
Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...A low pressure system approaching the southern
California coast will move across the area Monday. This system
will spread moisture up across AZ tonight with showers developing
west of Tucson spreading slowly east. Showers will end from the
west Monday night. Significantly cooler temperatures Monday.
Drying Tuesday with continued cool conditions, then temperatures
will rise back to seasonal norms for the remainder of the week
with a return to rather low RH levels. Winds will be relatively
light through the week with normal diurnal trends.
&&
.PREV DISCUSSION...Showers will continue to increase across
western Pima county through the early evening hours and also
slowly spread east. All of this is being driven by a strong upper
level trof approaching the southern California coast. Latest water
vapor imagery showed that a closed low is developing in this trof
as it moves east. Dynamics will increase across the forecast area
over the next 12 hours with areal coverage of showers increasing.
In fact likely to see 2-4 hours of steady rain versus showers.
Also can`t rule out a lightning strike or two, especially on
Monday.
As the trof axis pushes across the state on Monday into Monday night
showers will be ending from west to east with a few lingering
showers early Tuesday east of Tucson. Snow levels will be lowering
below the mountain tips Monday morning with slushy snow amounts
above 9000 feet of 1"-3", especially in the White mountains. Storm
total liquid amounts were range from 0.15" to 0.60" in the valleys
with up to 1.20" in some of the mountain ranges thanks to pretty
good upslope flow.
Much cooler Monday with highs, depending on location, about 10-20
degrees cooler than today.
Dry conditions return to the area Tuesday and will continue into
Saturday Highs below normal Tuesday then be a few degrees above
normal through next Sunday. Models hinting at another weather system
impacting the state either late next Sunday or early next Monday.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Area Forecast Discussion
National Weather Service Binghamton NY
444 AM EST Mon Nov 21 2016
.SYNOPSIS...
Significant lake effect snow will continue today across portions
of central New York and northeast Pennsylvania. Winds will remain
strong and gusty which will result in blowing and drifting snow.
Snow intensity decreases tonight and Tuesday but snow showers will
linger with light accumulations.
&&
.NEAR TERM /THROUGH TONIGHT/...
430 AM Update...
High end lake effect event will continue today with gusty winds
also causing blowing and drifting snow.
The unusual thing about this lake effect snow event is that while
there is the usual shallow lake effect moisture, there is also
significant Atlantic moisture contribution in the mid levels
wrapping around the back side of the upper low. This moisture
stream can be seen on water vapor imagery connection from
northeast of Bermuda, up between Nova Scotia and Newfoundland,
then back through Central to Western Quebec, and finally far
eastern Ontario including Lake Ontario to Upstate New York. This
has contributed to a very deep moisture atmospheric profile with
thick saturated dendritic growth zone. That is, that layer which
is 12 to 18 degrees below zero Celsius which supports very fluffy
dendrite crystals that rapidly accumulate.
On the very periphery of the mid level Atlantic moisture feed,
back in the lower levels we have lake to lake connection from
Georgian Bay of Lake Huron through Lake Ontario. This is what
produced the surprisingly persistent intense lake effect band
from roughly Penn Yan through Ithaca through Binghamton and even
extending into northeast Susquehanna-northern Wayne Counties of
PA from late yesterday all the way through most of the night. We
have had several reports from Western Broome-Northern Tioga-
Northern Susquehanna counties either approaching or in excess of
a foot of snow. This includes 16 inches in Endwell BEFORE
midnight, and the snow has continued since. Other bands have
now become more established from Syracuse through Hamilton and
Hartwick, as well as Marcellus to Norwich, and much of Oneida
County. Snowfall rates in the heaviest portions of these bands may
exceed an inch per hour.
Canadian GEM model has been handling this situation best compared
to observations-radar and this model as well as latest runs of
high resolution models such as the HRRR were leaned on for
evolution of things today. The big Georgian Bay-connected band
will edge northward this morning, slipping out of the corner of
Northeast PA as well as southern Tioga-southwestern Broome
Counties. However, it may undergo further intensification across
the Northern Finger Lakes region into Cortland-Chenango-Otsego-
Delaware Counties while absorbing even more of Lake Huron`s
moisture upstream. The same can be said of bands across the
Syracuse to Rome areas. So while intensity will diminish a bit on
the southern edge of this activity, this event is still very much
in progress and accumulations will continue through the day
especially in Central New York where another 5 to 10 inches can be
expected.
For the lake effect event total, including what fell yesterday
afternoon onward through today, we will likely see several
reports in excess of 20 inches where the heaviest bands have been
most persistent, and at higher elevations that will continue to
have a significant west-northwest wind upslope lift contribution
such as the mountains south of the NY Thruway.
Even outside the main lake effect bands, there will be plenty of
snow showers-flurries, and regardless, strong northwest winds will
continue to robustly blow and drift the dry fluffy snow already on
the ground. Gusts will still frequently reach into the 35-45 mph
range with a few peak gusts to near 50 mph at highest elevations.
Current set of Lake Effect Snow Warnings and Advisories is
scheduled to expire at 7 PM this evening. However, it is appearing
likely that lake effect snow will continue through Tonight in the
Twin Tiers and especially Central New York. Snowfall rates will be
much less than currently, but 1 to 3 additional inches will be
possible Tonight, and thus we may end up having to extend a part
of the Warnings-Advisories beyond 7 PM this evening.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
320 am UPDATE...
While not as intense as what we are seeing now, lake snows linger
into a good part of Tuesday. Inversion heights are lower but we
still have deep moisture through the column, which will continue
snow showers across much of NY State. High pressure briefly builds
in Tuesday night into the first half of Wednesday, with a period
of dry weather. The next system will move across the Ohio Valley
and over our area Thanksgiving Day. Still a lot of model
uncertainty with regards to thermal profiles. The majority of the
soundings support at least some sort of mix (freezing rain or a
bit of snow) Wednesday night. By daybreak Thursday and for the
rest of the day mainly rain is expected with warmer air moving in.
The exception may be east of I-81 through mid morning, where
surface temps normally struggle to warm up fast. Saving grace will
be low QPF amounts but given the high travel period, any amount of
ice or wintry weather is too much.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
330 AM Update...
Active pattern through Saturday night with weak
systems moving through and marginally cold air. The translation
will be a bit of rain, a bit of snow, and overall amounts pretty
low. Drier weather and ridging Sunday before we turn unsettled
again early next week.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
Lake effect snow will cause restrictive conditions to persist for KBGM-
KITH-KSYR-KRME most of the TAF period, and at times for KELM
early this morning. VIS will be typically below alternate minimums
due both to falling snow in lake effect snow bands, and blowing-
drifting of the dry fluffy powder courtesy of gusts frequently in
28-38 knot range out of the west-northwest. Brief forays to around
airport mins are not out of the question within the most intense
bands. Sustained winds will generally be upper teens to lower 20s
knots. Slightly lighter wind at KELM, compared to the strong winds
aloft, will also produce marginal LLWS conditions for that
terminal early this morning. Much better conditions at KAVP; lake
effect flurries will cause MVFR conditions at times prior dawn,
otherwise generally low end VFR CIG yet still gusty winds from
the west-northwest.
OUTLOOK...
Early Tuesday...IFR or worse conditions are likely to continue at
times for KITH-KBGM 06Z-12Z Tuesday; and KSYR-KRME through Tuesday
morning due to lake effect snow.
Tuesday Afternoon-Wednesday...Mainly VFR.
Wednesday night-Thursday...Restrictions possible from rain showers,
perhaps beginning as light freezing rain.
Friday...Restrictions possible with mixed rain-snow showers.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...Lake Effect Snow Warning until 7 PM EST this evening for
PAZ039-040.
Wind Advisory until 7 PM EST this evening for PAZ038>040-043-
044-047-048-072.
NY...Lake Effect Snow Warning until 7 PM EST this evening for
NYZ009-015>018-023-025-036-037-044-045-055-056.
Wind Advisory until 7 PM EST this evening for NYZ024-055-056-
062.
Lake Effect Snow Advisory until 7 PM EST this evening for
NYZ022-024-046-057.
&&
$$
SYNOPSIS...Heden/MDP
NEAR TERM...MDP
SHORT TERM...Heden
LONG TERM...Heden
AVIATION...MDP
Area Forecast Discussion
National Weather Service Billings MT
238 AM MST Mon Nov 21 2016
.SHORT TERM...valid for Tdy and Tue...
Clouds were overspreading the forecast area early this morning
as jet energy moved through the eastern side of a splitting trough
that was seen over the western states on water vapor imagery. Jet
energy will bring divergence to the SW mountains today as the
trough moves E toward the area. Some Q-vector convergence will
move through the region today but the stronger forcing will remain
S of the area. Deep moisture will reach the western and central
zones today with /0.10/ to /0.20/ inches of QPF. The HRRR and CIPS
analogs were in agreement with other models on the precipitation
amounts which boosted confidence in the forecast. The best chances
for precipitation will be over the SW mountains and NE Bighorns
where 1-2 inches of snowfall are expected. Low precipitation
chances will be over the foothills/nearby plains. A weak cold
front over western MT will move E through the area today. Blended
model guidance gives high temperatures from the mid 40s to mid
50s. Today should not be windy overall.
Jet divergence reaches the NE Bighorn Mountains tonight as the
northern branch of the trough moves into the area with continued
weak Q-vector convergence. Cold advection will continue over the
area behind the front. Moisture will move south with time tonight,
so have lowered PoPs across the N. Continued high PoPs over the
southern mountains where the northerly flow will favor the NE
Bighorns. Big Horn County and KSHR also become favored in this
flow. 850 mb temperatures will fall to around zero degrees C which
will support a rain/snow mix over the plains. Low temperatures
will be in the upper 20s to lower 30s. Expect a tenth of an inch or
less of QPF over the plains with a bit higher amounts in the
southern mountains. Plains snow amounts will be light. KSHR could
see a half inch of snowfall. Several inches will fall over the
mountains.
The trough will push gradually E of the area on Tuesday. Moisture
supported low chances for snow over the southern mountains.
Temperatures will reach the 40s. Any remaining mountain moisture
shallows out Tue. night so kept the forecast dry. Lee troughing
sets up under the upper ridge which could bring gusty gap winds.
Have continued with stronger winds over the KLVM and Nye areas. So
far do not see the need for an Advisory, but will continue to
watch this situation. Arthur
.LONG TERM...valid for Wed...Thu...Fri...Sat...Sun...
Main forecast concerns for the extended period revolve around
light snow potential Wednesday night into Thanksgiving morning,
and a strong wind potential for western foothills Thursday
afternoon into Sunday.
Approaching Pacific system on Wednesday amplifies ridging over the
area for a mainly dry and breezy day. Western mountains and
foothills will see increasing precipitation chances through the
afternoon. Precipitation chances increase over central zones
during the evening hours as the Pacific front crosses the area.
This system should exit the area to the east Thanksgiving morning.
Latest models are a bit heavier on the precipitation with this
system than previous solutions, and the GFS is trending slower
than the European solution resulting in more accumulation. The
GEFS ensemble mean is showing 2 to 3 inches of snow accumulation
around Billings and Sheridan by early Thanksgiving morning, while
the European is indicating less than an inch. Increased
precipitation chances for this quick moving system and increased
snow accumulations to around an inch for the lower elevations
along and west of a Broadus to Harlowton line, as the best
dynamics ride along the Wyoming/Montana state line. Mountains
could see 3 to 6 inches out of this system.
This system quickly moves east of the area Thanksgiving morning
with a dry afternoon expected as shortwave ridging develops. Lee
side trofing will increase late in the day allowing winds to
increase along the western foothills. Latest progs indicate
potential for advisory type wind gusts over 60 mph developing
Thursday night. This windy pattern continues for the western
foothills through Saturday and into Sunday. For the plains this
downslope ridging will keep conditions mainly dry and
temperatures seasonal. Mountains will continue to see mid level
moisture pushing in from the west for occasional snow showers,
especially on west facing slopes in and around Cooke City.
Next significant trof moves in late Sunday with increasing
precipitation chances. Models showing a good deal of disagreement
on the strength and timing of this system so kept forecast pretty
broadbrushed and leaning toward the ensemble mean for now. Some
indication that an arctic intrusion could develop next Monday
with much colder air and accumulating snow into the middle of next
week. Chambers
&&
.AVIATION...
VFR conditions will prevail through most of the day today. By this
afternoon showers will develop over western mountains and
foothills with occasional MVFR conditions developing. These lower
flight conditions will spread eastward into the plains Monday
evening. Mountain obscuration will become more frequent as well
this afternoon. Gusty southwest winds can be expected over
western foothills through the morning with occasional gusts around
40kts in the KVLM vicinity. These winds are expected to weaken
late morning. Chambers
&&
.PRELIMINARY POINT TEMP/POPS...
Tdy Tue Wed Thu Fri Sat Sun
-------------------------------------------------------
BIL 050 031/045 027/044 030/041 028/045 030/043 027/039
2/W 31/B 01/B 62/J 11/B 01/B 01/B
LVM 049 028/045 029/045 025/040 030/045 030/041 026/038
3/W 31/B 02/W 62/J 11/N 22/J 12/J
HDN 050 027/048 023/045 030/043 025/046 027/044 024/041
1/E 31/B 01/B 63/J 11/B 01/B 01/B
MLS 052 031/046 025/046 028/046 025/049 027/046 025/045
1/E 11/B 00/B 33/J 00/B 01/B 01/B
4BQ 050 030/045 023/046 026/043 023/048 026/044 024/042
1/E 31/B 00/B 33/J 00/B 02/W 01/B
BHK 047 027/042 019/040 024/043 022/048 023/045 022/043
0/E 20/B 00/B 13/J 00/B 01/B 01/B
SHR 046 027/042 018/040 025/039 020/044 025/041 019/036
2/W 52/J 00/B 64/J 00/B 02/W 01/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
1032 PM PST Sun Nov 20 2016
.SYNOPSIS...
A storm system will begin to exit central California with a few
remaining showers through Monday afternoon. Most of the
precipitation will be over the Sierra-Nevada Mountains on Monday.
It will also be windy in spots through Monday evening. Otherwise,
another system may impact norther parts of the area by mid-week.
&&
.DISCUSSION...
145 pm PST radar shows a line of precipitation extending along a
cold front from Yosemite National Park south through San Luis
Obispo. Up to a third of an inch of rain has already been observed
in the parts of Merced County. The front will continue to push
east through central California during the afternoon and evening
hours on Sunday, bringing along with it the increased chance of
precipitation as moisture advects from the south. HRRR and high-
res WRF models advertise the rain approaching Fresno by mid-
afternoon to early evening. As the front pushes through, we`ll see
snow levels fall to around 7,000 feet - possibly as low as 6,500
feet - near Yosemite National Park where a Winter Weather Advisory
is in effect through 10 pm PST Sunday.
Showers will linger over the area Monday morning and afternoon,
especially for locations in the mountains, foothills and southern
San Joaquin Valley. While the upper low continues to push into the
North American continent, fog will become a concern in the San
Joaquin Valley for the Tuesday morning commute as a ridge builds
over the West Coast. Right now confidence is medium for fog
development, but its intensity and coverage is still unknown.
Tuesday`s ridge will be short-lived as another system approaches
the West Coast on Wednesday. This system still has some unknowns
with the timing and trajectory. 12Z GFS and ECMWF suggest
precipitation for the northern half of the CWA (Fresno County
northward) with the best potential in Yosemite National Park.
Thanksgiving Day looks to be mainly dry for holiday travelers
across the central California interior, but another storm system
will begin to aim on northern California late Thursday.
Precipitation chances for our area will begin to increase by the
Friday/Saturday time frame. Confidence for the timing and
placement of this storm system is low. Model uncertainty continues
to grow beyond Saturday, but it does appear the pattern will
remain unsettled for the West Coast into the end of November.
AVIATION...
In the southern Sierra...IFR conditions can be expected in Yosemite
National Park with IFR conditions spreading southward to Kings
Canyon National Park by 03z Monday. Mountain obscurations in heavier
precipitation.
In the Sierra foothills...MVFR conditions in Mariposa and Madera
County with MVFR conditions spreading southward into Tulare County
by 03z Monday.
Areas of MVFR ceilings can be expected along the north facing slopes
of the Tehachapi mountains between 06z and 18z Monday.
In the San Joaquin Valley...areas of MVFR ceilings are possible
north of Kern County through 18z Monday with local IFR ceilings in
Merced County between 12z and 16z Monday.
&&
.AVIATION...
In the southern Sierra...IFR conditions can be expected in Yosemite
National Park with IFR conditions spreading southward to Kings
Canyon National Park by 03z Monday. Mountain obscurations in heavier
precipitation.
In the Sierra foothills...MVFR conditions in Mariposa and Madera
County with MVFR conditions spreading southward into Tulare County
by 03z Monday.
Areas of MVFR ceilings can be expected along the north facing slopes
of the Tehachapi mountains between 06z and 18z Monday.
In the San Joaquin Valley...areas of MVFR ceilings are possible
between 00z and 18z Monday with local IFR ceilings in Merced County
between 12z and 16z Monday.
&&
.AIR QUALITY ISSUES...
None.
&&
.CERTAINTY...
The level of certainty for days 1 and 2 is low.
The level of certainty for days 3 through 7 is low.
Certainty levels include low...medium...and high. Please visit
www.weather.gov/hnx/certainty.php for additional information
an/or to provide feedback.
&&
.HNX Watches/Warnings/Advisories...NONE.
&&
$$
public...Rowe
avn/fw...Durfee
synopsis...Rowe
weather.gov/hanford
Area Forecast Discussion
National Weather Service Marquette MI
409 AM EST Mon Nov 21 2016
.SHORT TERM...(Today and tonight)
Issued at 343 AM EST MON NOV 21 2016
00Z raobs/latest wv imagery and RAP analysis show a confluent nw
flow alf over the wrn Great Lks btwn deep closed lo over New England
and an upr rdg in the Plains. Sfc hi pres under the associated deep
lyr qvector dvgc/subsidence stretches fm far nw Ontario to WI.
Despite the very dry air n of Lk Sup as shown on the 00Z YPL raob,
the nly flow/thermal trof with h85 temps as lo as -12C ahead of the
sfc hi pres rdg is causing a good deal of lo cld cover over Upr MI.
The lo clds have begun to break over the far wrn U.P. near the sfc
rdg axis and over the e as well with a shorter fetch to moisten the
upstream dry air. But considerable mid cld has moved into the w
ahead of a shrtwv riding over the upr rdg axis. Despite the
favorable thermal contrast over the relatively warm lk waters, lo
subsidence invrn base near 4k ft agl per RAP analysis and upstream
llvl dry air has resulting in no more than very light sn showers/
flurries downwind of Lk Sup.
Main fcst concerns in the short term are on cld cover/impact on
temps.
The upr rdg is fcst to amplify and shift slowly to the e, reaching
the wrn Great Lks late tngt. As this upr rdg moves to the e, so wl
the sfc hi pres rdg. The combination of lowering subsidence invrn
base/incrsg llvl acyc flow/the llvl dry air wl result in a gradual
erosion of the lingering lo clds and end any lingering light sn
showers/flurries. These clds wl be most resilient over the ncentral
with upslope nly flow/longer over water fetch. The incrsg mid lvl
subsidence wl also tend to grdly dry out the mid clds now streaming
into wrn Upr MI. Best chc for more sunshine this aftn wl be near the
WI border, allowing max temps to reach at least 32 over the scentral
with a downslope wind component. Under moclr skies/lgt winds tngt in
the presence of pwat aob 0.25 inch, tended to hedge toward the lo
end of guidance for min temps away fm the ncentral, where more lo
clds may linger. The arrival of some hi clds spilling over the upr
rdg axis late over the w may tend to hold the temps up there a bit.
.LONG TERM...(Tuesday through Sunday)
Issued at 407 AM EST MON NOV 21 2016
Mid clouds thicken on Tue but should remain dry and seasonable as
temps reach low to mid 30s and winds stay light. By far the focus of
long term is on shortwave trough crossing southern California this
morning. Trough is forecast to cross the southern plains on Tue
morning while another trough crosses farther north across the rockies
in ID and MT. Elongated sfc trough will connect the two features
early on Tue but by Tue evening, trough will consolidate into sfc low
over the central plains, vcnty of eastern KS or western MO. Ahead of
the low, a ridge of high pressure with dry air will be over the Great
Lakes. Models vary on extent of dry air which will affect how quickly
precip, in the form of snow for most cwa, moves over the Upper Great
Lakes on Tue night as the low crosses southern IA. Delayed pops over
far east cwa to account for the dry air but otherwise, advection of
deep moisture 925-500mb ahead of lead shortwave and inverted sfc
trough should support snow moving over west half of Upper Michigan.
Could see accumulations of 1-2 inches of wet snow across west third
of cwa with less than 1 inch farther into the central cwa.
Sfc low tracks across northern IL on Wed while inverted trough
extends northwest into northwest WI or even northeast MN. Widespread
precip will continue across Upper Michigan as another shortwave
trough lifts through region which enhances low-level convergence and
lift along the inverted trough. Main trend from models is to trend
upward with QPF for later in the day as main shortwave trough and h7-
h5 q-vector convergence spread across the cwa and as h85 low tracks
across western Upper Michigan. Primary question on Wed is not if
precip will occur but rather it what will ptype be - rain or snow.
Forecast soundings continue to show low wet-bulb zero heights less
than 500 ft agl so elevation and near sfc temps likely will
determine final ptype. As it looks now, only place with risk of
mainly rain throughout will be scntrl cwa as any initial snow will
give way to rain as temps quickly rise through the 30s with se winds
advecting warm air off Lk Michigan and the Bay of Green Bay. Only
place in cwa Tue night into Wed where mainly snow occurs will be the
higher terrain of west and ncntrl cwa (Watersmeet and Iron River
stretching northeast to Herman, Champion and Ishpeming). Interior
eastern cwa may also see mainly snow. Elsewhere, will be mainly
snow Tue night into Wed morning then a rain/snow mix on Wed aftn.
Total snowfall Tue night into Wed could push into the advy range
with best shot of seeing over 4 inches over the interior west and
ncntrl areas.
Into Wed night not sure how much temps will cool off as inverted
trough overhead will limit any significant cold air advection. Could
see temps in the late aftn on Wed only fall a couple degrees or stay
steady. Temps will have big impact on ptype on Wed night. Kept with
rain/snow mix most areas with greatest chance of only snow over the
interior west and ncntrl and also for the interior east were
additional snow accumulations of 1-2 inches look likely. Soundings
over the west also indicate once deeper moisture is stripped out at
temps lower than -5c late Wed night could see some drizzle or
freezing drizzle. Did not include that attm but will need to be
watched.
On Thanksgiving another shortwave trough is poised to cross cntrl
and eastern Upper Michigan. Pesky inverted trough remains in play to
provide a focus for additonal precip with the added large scale
support. Increased pops over consensus mainly from Keweenaw to
eastern cwa where low-level forcing is strongest. Ptype could still
be an issue especially in the morning. Best chance of seeing only
snow at least for the morning would be over interior east cwa.
Overall this low pressure system and widespread mixed precip will
affect one of the busiest travel days of the year and the messy
pytpe could push into Thanksgiving as well. With the messy ptype
issue and possible moderate snowfall, will issue an SPS to highlight
the hazards. Since snowfall rates do not appear to be too high at
any time during the Tue night through Wed night time frame and sfc
temps will be near or even above freezing, the main treated roads
probably will remain wet during the day on Wed. On the other hand
the snow that occurs will be a sloppier/wetter type with SLRs around
10:1 if not even lower.
Beyond Thanksgiving, rode with consensus of the models. Chance pops
still affect the area on Friday. Could see light accumulating snow
as quick moving disturbance crosses the Upper Great Lakes. General
break in wx on Sat as high pressure ridge crosses then increasing
chances for more widespread precip later Sun and/or Mon as another
low pressure system affects the region. Ptype will remain an issue
with temps expected to be a few degrees either side of the freezing
mark.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1125 PM EST SUN NOV 20 2016
Chilly air mass over Lake Superior along with northerly winds will
result in MVFR stratocu prevailing thru this fcst period at
KIWD/KCMX/KSAW. However, with high pres ridge settling over western
Lake Superior Mon, increasing anticyclonic flow may cause stratocu
to sct out at KIWD Mon morning and at KCMX and KSAW Mon
afternoon.
&&
.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 343 AM EST MON NOV 21 2016
As a hi pres ridge over the western Great Lakes shifts slowly to the
e thru Tue, expect lingering n winds up to 25-30 kts over eastern
Lake Superior to diminish thru today and hold under 20 kts thru Tue.
Over the w half, light winds today and tonight will become ese and
increase to 20-25 kts on Tue/Tue night under the sharpening pres
gradient between the slowly departing hi pres and a lo pres moving
ene toward the Lower Great Lakes. These stronger ese winds will
arrive over the e by early Wed, when ese winds up to 20-30 kts will
be the rule across the entire lake. As this low moves to the e on
Thu, winds will diminish under 20 kts and back to the n-ne as a lo
pres trough lingers nearby. Winds under 20 kts on Fri will slowly
back to the w-nw ahead of an approaching hi pres ridge.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...07
MARINE...KC
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
316 AM CST Mon Nov 21 2016
.SHORT TERM...(Today and tonight)
Issued at 316 AM CST Mon Nov 21 2016
Upper trough axis is currently entering onshore this morning, while
midlevel moisture streams east towards the central plains. An area
of low pressure across central CO has kept winds up at 5 to 10 mph
from east southeast across northeast Kansas with lows a few degrees
warmer in the upper 20s to lower 30s.
High clouds gradually increase later today as the upper trough
progresses over the four corners region. In turn, sfc trough deepens
and pushes east into western KS, inducing southerly sfc winds from
10 to 15 mph sustained in the afternoon. The ample dry air and
warmer temps up to 9C just off the sfc on the HRRR suggest that the
stronger winds today should mix these temps down in addition to the
warm air advection from the south. The only hindrance to the warmer
temps is the overcast skies during peak heating so have not sided as
warm as the HRRR, but closer to the GFS mos guidance in the middle
to upper 50s for highs. Tonight, mid level moisture gradually
advects northward as a lead vorticity maximum ejects toward Nebraska
and central Kansas after midnight. Forecast soundings across the
area suggest saturation may not be adequate for rain showers until
sunrise Tuesday. Have best chances for precipitation closer to the
maximum lift over north central areas, increasing to a chance of
showers elsewhere after 3 am. There is less than 100 J/KG of mixed
layer cape so I mentioned a slight chance for thunder, but overall
scattered rain showers are the primary precip type.
.LONG TERM...(Tuesday through Sunday)
Issued at 316 AM CST Mon Nov 21 2016
Showers and thunderstorms look likely for Tuesday morning as the
shortwave passes across the forecast area. Models show the
strongest forcing to impact the area through the morning with the
dry slot working its way across central and into eastern KS
during the afternoon. Lapse rates should be steep enough for some
thunder with the showers, although models have trended to
advecting a stratus deck north ahead of the forcing which would
limit insolation and destabilization. Because of this think
thunderstorms will tend to be more isolated due to limited
instability. There may also be a brief period of wrap around
precip Tuesday evening before the system moves east and dry air
advects in from the northwest. It continues to look like the
precip will come to an end before the cold air arrives so there
is not much concern for frozen precip. Models overall are still
not that impressed with precip amounts in spite of PWs increasing
to around 1 inch, which for this time of year is pretty moist. I
suspect the reason is an inversion capping the boundary layer with
no real good source of lift. Nevertheless there should be more
than enough large scale forcing that most areas should see some
rain. Given the progressive nature of the system, amounts around a
quarter of an inch appear to be plausible. With the expected cloud
cover limiting sunshine, have cooled the forecast highs for
Tuesday a couple degrees.
Wednesday and Wednesday night continue to appear dry with
shortwave ridging overhead. Although another progressive shortwave
is anticipated to move overhead late in the day Thursday and
Thursday evening. Models have trended further south with the
better forcing from this wave. However moisture continues to be a
big limiting factor regarding precip chances. The GFS shows a lot
less moisture advection ahead of this wave due to surface ridging
along the TX gulf coast. Model blends have inserted a low POP
across far northeast KS Thursday evening as the wave passes. Have
kept some slight chance POPs for collaboration, but given the
limited moisture think this may be generous.
Confidence in the forecast becomes a little lower by the weekend
as the ECMWF and GFS have been inconsistent in the shortwave
details beyond 132 hours. There remains signs for another wave to
dig through the central Rockies and lift out through the plains.
But models have trended to keep this feature west of the forecast
area until Sunday or possibly Monday. The GFS ensemble members
show the shortwave anywhere from the central plains to southern CA
at 12Z Sunday. So the forecast is a blend of available guidance
which has some slight chances for Sunday. The details of the
forecast area likely to change as the forecast gets closer in
time.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1138 PM CST Sun Nov 20 2016
VFR conditions are expected throughout the period. Southeasterly
winds will remain light at 5-10 knots through the period. LLWS may
increase near the end of the period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Prieto
LONG TERM...Wolters
AVIATION...Baerg
Area Forecast Discussion
National Weather Service Albany NY
918 AM EST Mon Nov 21 2016
.SYNOPSIS...
Low pressure just north of New England will remain nearly
stationary through today, then slowly move east to Maine and then
Newfoundland on Tuesday. A northwesterly flow of cold and moist
air will bring cold weather and areas of snow to the region. The
highest snowfall accumulations are forecast for the hill towns and
mountains and in persistent lake effect snow bands.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
As of 918 AM EST...A stacked low pressure system remains situated
just north of northern New England over southern Quebec. The cold
and cyclonic flow around this system is teaming up upslope flow
and lake-effect moisture to continue to produce snow showers and
flurries across the area, especially the higher elevations.
The heaviest snowfall remains within a narrow lake-effect band
across Schoharie County into southwestern Albany county, northern
Greene County and into North-Central Columbia county. Snowfall
rates are one half inch to one inch per hour at times within this
very narrow band. Based on the latest HRRR guidance, this band
will gradually weaken over the next few hours.
The upslope into the Taconics, Berkshires and southern VT is not
as heavy as what it was earlier in the morning, but will continue
to go with likely pops through the remainder of the morning due
to persistent light snowfall. This too will gradually weaken by
this evening, as the whole upper level system starts to fill and
weaken.
The latest snowfall forecasts, graphical and in the text, are for
additional snowfall, on top of what has fallen. Please refer to
our Public Information Statements for the latest real time
snowfall reports. The range of snow that has fallen is quite
extreme with dustings in valleys and a foot or more in higher
elevations. The difference in just a few hundred feet in elevation
or a few miles distance can be the difference between an inch and
6 or more inches.
Needless to say, headlines are tied to an average of snowfall
amounts over regions that are observing some of these extreme
ranges in short distances and changes in elevation. Tracking
frequent shifts and changes in intensity of snow areas in this
storm over the last couple of days has been quite a busy time.
The upslope and lake effect snows will gradually decrease in
coverage and close monitoring of the radar will continue, as there
are signals now that strong winds through the depth of the clouds
are blowing the snow downstream, meaning the heavier snow is
falling east and south of where the highest reflectivities are
seen on radar.
Since bands and areas of snow should persist into tonight, some
warnings and advisories may need to be extended but data and
guidance later today will help decide what is needed for tonight.
So, with clouds, periods of snow showers and windy conditions,
highs today in the 30s with 20s higher terrain.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
Snow shower activity slowly decreases in coverage tonight through
Tuesday and clouds persist through Tuesday in many areas. Some sun
is possible in western areas depending on much progress east the
upper cut off tracks by later Tuesday. Highs Tuesday in the mid
30s to around 40 but upper 20s to lower 30s higher terrain.
On Wednesday, more improvement as flat upper ridging and some
slight moderation of temperatures occurs. However, some high
clouds in advance of the next system may spread across our region
through the afternoon. Light winds and snow pack could lessen our
mixing potential and highs are expected to be in the upper 30s to
lower 40s but around 30 to lower 30s northern areas.
By Wednesday night, an upper impulse approaches with weak warm
advection and isentropic lift. Clouds thicken through the night
and later at night there are some chances for light mixed
precipitation, mainly snow and sleet but will have to watch for
freezing rain potential as we get nearer to Wednesday night. Lows
in the 20s to around 30.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
The period starts out on Thanksgiving Day with a short wave trough
aloft moving eastward across the area, with the surface reflection a
weak area of low pressure tracking from near Lake Erie to western NY
by late in the day. Some forcing associated with weak isentropic
lift and cyclonic vorticity advection aloft should result in areas
of light precip. Models indicating spotty QPF at this time, so will
continue to mention high chance pops. Ptype looks to be a transition
from light snow showers to light rain showers through the day, with
valley areas changing more quickly than the higher terrain. There is
a low probability of a wintry mix, but will not include mention at
this time. GFS forecast soundings thermal profiles indicate a snow
to rain scenario. It will be a cool and cloudy Thanksgiving with
high temps only ranging from the mid 30s to lower 40s.
The first short wave trough starts to move away from the region
Thursday night, with some ridging developing by Friday morning. Will
mention a low chance for a few leftover rain/snow showers during
this time. The next deeper upper level trough approaches from the
Great Lakes late Friday, with again some light rain/snow showers
possible just ahead of this system.
The upper trough axis looks to move across the region Friday night
into Saturday bringing a somewhat better chance for rain/snow
showers. The best chance for snow showers will be at night for most
areas and across the higher terrain during the daylight hours. Some
sources of guidance indicating possible coastal development across
southeast New England on Saturday, which could result in a period of
steadier precip so will have to watch trends since temps may be cold
enough for snow if the cyclone deepens enough.
Models then showing ridging developing at the surface and aloft on
Sunday, with the first decent chance of some appreciable sunshine in
several days.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
Low pressure just north of New England will remain nearly
stationary through today, then slowly move east to the Canadian
Maritimes by Tuesday. A northwesterly flow of cold and moist air
across the Great Lakes will continue to bring areas of snow
showers to the region.
Snow showers will be most persistent today at KPSF with upslope
flow, where MVFR with occasional IFR conditions are likely
through around 16Z. At KALB/KGFL/KPOU mainly VFR with brief
periods of MVFR conditions with any light snow showers. Upslope
snow showers will still be around into the afternoon, especially
at KPSF where mainly MVFR conditions expected there.
Primarily VFR conditions will prevail elsewhere with flurries
this afternoon. Snow showers should dissipate by this evening with
prevailing VFR conditions.
Winds today will be westerly around 15-20 kt with gusts around
25-35 kt. Wind gusts will be strongest at KALB/KPSF.
Outlook...
Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: No Operational Impact. NO SIG WX.
Wednesday Night: Moderate Operational Impact. Chance of SN...SLEET.
Thanksgiving Day: Moderate Operational Impact. Chance of SHRA...SHSN.
Thursday Night: Moderate Operational Impact. Chance of SHRA...SHSN.
Friday: Moderate Operational Impact. Chance of SHRA...SHSN.
Friday Night: Moderate Operational Impact. Chance of SHRA...SHSN.
Saturday: Moderate Operational Impact. Chance of SHRA...SHSN.
&&
.FIRE WEATHER...
Low pressure slowly moving away with snow showers and windy
conditions today. Gradually improving conditions tonight and
Tuesday.
&&
.HYDROLOGY...
Snow is in the forecast with accumulations occurring across the
much of the area with the highest amounts across the higher
terrain through tonight. More precipitation is expected during
the mid week period heading into Thanksgiving Day but could be a
light mix of snow, sleet and rain.
For details on specific area rivers and lakes, including observed
and forecast river stages and lake elevations, please visit the
Advanced Hydrologic Prediction Service /AHPS/ graphs on our
website.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...Wind Advisory until 6 PM EST this evening for CTZ001-013.
Winter Storm Warning until 7 PM EST this evening for CTZ001.
NY...Winter Weather Advisory until 7 PM EST this evening for NYZ041-
043-048-053-063-066-083-084.
Wind Advisory until 6 PM EST this evening for NYZ032-033-
038>043-047>054-058>061-063>066-082>084.
Winter Storm Warning until 7 PM EST this evening for NYZ051-
054-058-061.
Lake Effect Snow Advisory until 7 PM EST this evening for
NYZ039-040-042-047-082.
Lake Effect Snow Warning until 7 PM EST this evening for
NYZ032-033-038.
MA...Wind Advisory until 6 PM EST this evening for MAZ001-025.
Winter Storm Warning until 7 PM EST this evening for MAZ001-
025.
VT...Wind Advisory until 6 PM EST this evening for VTZ013>015.
Winter Storm Warning until 7 PM EST this evening for VTZ013-
014.
&&
$$
SYNOPSIS...NAS
NEAR TERM...Frugis/NAS
SHORT TERM...NAS
LONG TERM...JPV
AVIATION...JPV
FIRE WEATHER...NAS
HYDROLOGY...NAS
Area Forecast Discussion
National Weather Service Binghamton NY
646 AM EST Mon Nov 21 2016
.SYNOPSIS...
Significant lake effect snow will continue today across portions
of central New York and northeast Pennsylvania. Winds will remain
strong and gusty which will result in blowing and drifting snow.
Snow intensity decreases tonight and Tuesday but snow showers will
linger with light accumulations.
&&
.NEAR TERM /THROUGH TONIGHT/...
645 AM Update...
As expected the Georgian Bay-rooted heavy band is edging
northward, now roughly from Seneca Falls to Cortland to southern
Chenango County and into southwestern Delaware County. Both this
band and the thinner Oneida Lake-to-Augusta-to-Hartwick band
extend all the way to Long Island, though is spaces between radars
it is harder to see since the beam overshoots them. With the thick
and moist dendritic growth layer, even in between the bands there
is a still a good amount of flakes.
Previous discussion...
High end lake effect event will continue today with gusty winds
also causing blowing and drifting snow.
The unusual thing about this lake effect snow event is that while
there is the usual shallow lake effect moisture, there is also
significant Atlantic moisture contribution in the mid levels
wrapping around the back side of the upper low. This moisture
stream can be seen on water vapor imagery connection from
northeast of Bermuda, up between Nova Scotia and Newfoundland,
then back through Central to Western Quebec, and finally far
eastern Ontario including Lake Ontario to Upstate New York. This
has contributed to a very deep moisture atmospheric profile with
thick saturated dendritic growth zone. That is, that layer which
is 12 to 18 degrees below zero Celsius which supports very fluffy
dendrite crystals that rapidly accumulate.
On the very periphery of the mid level Atlantic moisture feed,
back in the lower levels we have lake to lake connection from
Georgian Bay of Lake Huron through Lake Ontario. This is what
produced the surprisingly persistent intense lake effect band
from roughly Penn Yan through Ithaca through Binghamton and even
extending into northeast Susquehanna-northern Wayne Counties of
PA from late yesterday all the way through most of the night. We
have had several reports from Western Broome-Northern Tioga-
Northern Susquehanna counties either approaching or in excess of
a foot of snow. This includes 16 inches in Endwell BEFORE
midnight, and the snow has continued since. Other bands have
now become more established from Syracuse through Hamilton and
Hartwick, as well as Marcellus to Norwich, and much of Oneida
County. Snowfall rates in the heaviest portions of these bands may
exceed an inch per hour.
Canadian GEM model has been handling this situation best compared
to observations-radar and this model as well as latest runs of
high resolution models such as the HRRR were leaned on for
evolution of things today. The big Georgian Bay-connected band
will edge northward this morning, slipping out of the corner of
Northeast PA as well as southern Tioga-southwestern Broome
Counties. However, it may undergo further intensification across
the Northern Finger Lakes region into Cortland-Chenango-Otsego-
Delaware Counties while absorbing even more of Lake Huron`s
moisture upstream. The same can be said of bands across the
Syracuse to Rome areas. So while intensity will diminish a bit on
the southern edge of this activity, this event is still very much
in progress and accumulations will continue through the day
especially in Central New York where another 5 to 10 inches can be
expected.
For the lake effect event total, including what fell yesterday
afternoon onward through today, we will likely see several
reports in excess of 20 inches where the heaviest bands have been
most persistent, and at higher elevations that will continue to
have a significant west-northwest wind upslope lift contribution
such as the mountains south of the NY Thruway.
Even outside the main lake effect bands, there will be plenty of
snow showers-flurries, and regardless, strong northwest winds will
continue to robustly blow and drift the dry fluffy snow already on
the ground. Gusts will still frequently reach into the 35-45 mph
range with a few peak gusts to near 50 mph at highest elevations.
Current set of Lake Effect Snow Warnings and Advisories is
scheduled to expire at 7 PM this evening. However, it is appearing
likely that lake effect snow will continue through Tonight in the
Twin Tiers and especially Central New York. Snowfall rates will be
much less than currently, but 1 to 3 additional inches will be
possible Tonight, and thus we may end up having to extend a part
of the Warnings-Advisories beyond 7 PM this evening.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
320 am UPDATE...
While not as intense as what we are seeing now, lake snows linger
into a good part of Tuesday. Inversion heights are lower but we
still have deep moisture through the column, which will continue
snow showers across much of NY State. High pressure briefly builds
in Tuesday night into the first half of Wednesday, with a period
of dry weather. The next system will move across the Ohio Valley
and over our area Thanksgiving Day. Still a lot of model
uncertainty with regards to thermal profiles. The majority of the
soundings support at least some sort of mix (freezing rain or a
bit of snow) Wednesday night. By daybreak Thursday and for the
rest of the day mainly rain is expected with warmer air moving in.
The exception may be east of I-81 through mid morning, where
surface temps normally struggle to warm up fast. Saving grace will
be low QPF amounts but given the high travel period, any amount of
ice or wintry weather is too much.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
330 AM Update...
Active pattern through Saturday night with weak
systems moving through and marginally cold air. The translation
will be a bit of rain, a bit of snow, and overall amounts pretty
low. Drier weather and ridging Sunday before we turn unsettled
again early next week.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
Lake effect snow will cause restrictive conditions to persist for
KBGM-KITH-KSYR-KRME through the day, and to a lesser degree KELM.
KAVP meanwhile will remain VFR, though a flurry or two is still
possible. For the NY terminals, VIS will be typically below
alternate minimums due both to falling snow in lake effect snow
bands, and blowing-drifting of the dry fluffy powder courtesy of
gusts frequently in the 28-35 knot range out of the west-northwest
today. Brief forays to around airport mins are not out of the
question within the most intense bands. As depth of snow-producing
clouds becomes shallower tonight, and winds diminish, very gradual
improvement will occur though at least IFR VIS will still be
possible through 12Z Tuesday for KSYR and perhaps KRME, as well as
MVFR CIGS for all the NY terminals and often at Fuel Alt Required
levels. Marginal LLWS will also exist at KELM-KBGM briefly this
morning before winds mix down a bit more later this morning.
OUTLOOK...
Tuesday Morning...Intermittent restrictions still possible from
lingering lake effect snow, especially KSYR-KRME. KAVP VFR.
Tuesday Afternoon-Wednesday...Mainly VFR.
Wednesday night-Thursday...Restrictions possible from rain showers,
perhaps beginning as light wintry mix/freezing rain.
Friday...Restrictions possible with mixed rain-snow showers.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...Lake Effect Snow Warning until 7 PM EST this evening for
PAZ039-040.
Wind Advisory until 7 PM EST this evening for PAZ038>040-043-
044-047-048-072.
NY...Lake Effect Snow Warning until 7 PM EST this evening for
NYZ009-015>018-023-025-036-037-044-045-055-056.
Wind Advisory until 7 PM EST this evening for NYZ024-055-056-
062.
Lake Effect Snow Advisory until 7 PM EST this evening for
NYZ022-024-046-057.
&&
$$
SYNOPSIS...Heden/MDP
NEAR TERM...MDP
SHORT TERM...Heden
LONG TERM...Heden
AVIATION...MDP
Area Forecast Discussion
National Weather Service Denver/Boulder CO
350 AM MST Mon Nov 21 2016
.SHORT TERM...(Today and tonight)
Issued at 344 AM MST Mon Nov 21 2016
SW flow aloft will remain over the area thru this aftn as a weather
system nears the four corners area by late this aftn. At the sfc
low pressure will dvlp nr Denver through the day.
Overall there may end up being a weak disturbance ahead of the main
system which will bring an increasing chance of showers to the mtns
by early aftn with some of these affecting the Front Range by late
aftn into the early evening hours. As for highs latest hi res data
suggest readings over nern CO will rise into the upper 50s to mid
60s except possibly over the far nern plains where highs may stay in
the lower 50s.
For tonight the main part of the weather system will track across
the rgn as sfc low pres moves into sern CO. With increasing QG
ascent along with deeper moisture should see an increase in snow
across the mtns although orographic component is rather weak. Across
nern CO outside of a chance of early evening showers best chc of
additional pcpn may not dvlp until after midnight as a surge of
cooler air behind a fnt moves across the plains. Buffer soundings
show airmass will be wrm enough for pcpn to stay mainly as rain blo
6000 ft so will only indicate a mix of rain and snow towards 12z.
.LONG TERM...(Tuesday through Sunday)
Issued at 344 AM MST Mon Nov 21 2016
At 12Z Tuesday morning, an upper trough axis is over the central
CWA with fairly weak westerly flow aloft. By afternoon and Tuesday
night stronger northwesterly flow aloft is in place. The next
upper ridge is over the CWA on Wednesday. By afternoon, the upper
level winds are becoming southwesterly with the next upper trough
over the eastern Great Basin by 00Z Thursday. By 12Z Thursday
morning, a weak upper trough axis is over the forecast area. There
is fairly strong upward QG vertical velocity over the CWA Tuesday
morning. Downward motion is in place by Tuesday afternoon through
about noon Wednesday. Upward energy returns Wednesday afternoon
well into Wednesday night, with downward over the western CWA by
12Z Thursday morning. The boundary layer winds are progged to be
north-northwesterly Tuesday and Tuesday evening, then return to
more normal diurnal patterns overnight. South-southwesterlies are
progged on Wednesday, with normal drainage mixed with downsloping
Wednesday night. There is deep and widespread moisture over the
CWA Tuesday morning, then a significant decrease through the
afternoon and evening. There is very little moisture left Tuesday
night after 06Z. Wednesday is quite dry, with an increase of
moisture over the mountains Wednesday night. The QPF fields have
some measurable precipitation for most of the CWA Tuesday morning.
By afternoon, the plains are dry, but there is a tad left in the
mountains. This continues into early evening mainly due to
orographic enhancement. There is no precipitation noted for the
CWA the rest of Tuesday night and Wednesday. A bit of QPF returns
over the high county Wednesday night. For pops, will keep them
high for the first half of Tuesday, then decrease them greatly by
afternoon, with only "chance"s left in the mountains and 10-20%s
over the far northeast corner. Will go with dry Tuesday night and
Wednesday, then bring back 30-70%s for the mountains Wednesday
night due to the next trough. The advisory highlights in zones
31, 33 and 34 look good through 00Z late Tuesday afternoon.
Concerning temperatures, Tuesday highs are 5-8 C colder than this
afternoon`s. Wednesday`s temperatures are 3-4 C warmer then
Tuesday`s. For the later days, Thursday through Sunday, models
have northwesterly flow aloft on Thursday with upper ridging
Thursday night and Friday. On Saturday and Sunday, the models have
strong zonal flow over the CWA, with a weak upper trough or two
depending on the model. The GFS and ECMWF are not in sync Saturday
or Sunday. Will have some minor alpine pops in for those two days
for now.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 344 AM MST Mon Nov 21 2016
Winds were mixed early this morning however they should become more
sly by 15z. For this aftn a sfc low will dvlp south of Denver with
winds becoming more ely by 20z. Meanwhile both the HRRR and RAP
indicate a band of showers may move across between 22z and 02z with
ceilings lowering to 6000 ft for a few years.
For this evening as sfc low moves se winds should gradually become
more nly with increasing speeds by midnight as a cold fnt moves
across. There may still be a period of rain beginning around 09z
lasting to around 15z. Buffer soundings show airmass may stay wrm
enough for just a mix of rain and snow with any accumulation
confined to grassy areas with amounts under one half inch. Ceilings
will gradually to around 2000 ft overnight behind fnt and continue
into Tue morning.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 5 PM this afternoon to 5 PM MST
Tuesday for COZ031-033-034.
&&
$$
SHORT TERM...RPK
LONG TERM...RJK
AVIATION...RPK
Area Forecast Discussion
National Weather Service State College PA
1051 AM EST Mon Nov 21 2016
.SYNOPSIS...
An upper low over New England will slowly drift northeast toward
the Canadian maritimes early this week. Weakening low pressure
lifting out of the Mississippi Valley will likely track just north
of Pennsylvania Wednesday night or Thursday.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Inversion heights remain around 7k feet maintaining lake effect
snow showers and flurries in moderate northwest flow. Overall
trend of weakening lake effect will continue this afternoon as
upper low pulls away and inversion heights very slowly lower. For
most of the Allegheny Plateau, additional accum will be less than
one inch. Latest HRRR maintains disorganized Lake Huron banding
persisting through this afternoon over portions of the Northwest
Mountains and West Central mountains. Localized additional amounts
of an inch or so are possible from this band into Clearfield
County.
Model soundings continue to support occasional gusts over 40kts
today across the eastern half of the state, where wind advisory
remains in effect.
Ensemble mean 8h temps around -10C indicate max temps will
struggle to reach 32F over the high terrain of Central Pa and
reach only the low 40s across the Susq Valley.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
Lake effect snow showers/flurries will continue over the NW Mtns
tonight with any additional accums of under an inch. Surface ridge
will then build into the state Tuesday, resulting in brightening
skies, diminishing wind and slightly milder temps.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
The fair weather will continue into Wednesday before another weak
upper trough and surface cold front brings the next chance for
widespread precip by later Wednesday into Thursday.
Precipitation type issues could arise ahead of this next system,
as air and wet bulb temperatures aloft will be marginally cold
over about the northern half or so of the forecast area. I also
inserted the mention of pockets of freezing rain overnight as
surface temperatures could drop to freezing in some of the normal
cold spots. It doesn`t look like a big QPF event but things could
potentially get slippery Wednesday night into early Thursday. Too
early to be specific.
00Z ECENS and NAEFS both indicate the passage of a shortwave late
Friday into early Saturday. Ensemble mean 8H temps suggest rain
showers are likely, as weak surface low tracks north of Pa.
However, thermal profiles could become marginally cold enough for
lake effect snow showers behind this system early Saturday. Fair
and seasonable conditions appear likely by late next weekend, when
both ECENS/NAEFS show ridging building over the northeast CONUS.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
Strong WNW upslope flow will keep generally MVFR restrictions in
place (with occasional IFR) across the northern/western TAF sites
of KBFD/KJST, with occasional incursions into the central mtns
near KAOO/KUNV as snow showers continue into this afternoon. By
mid afternoon, snow showers should mainly be confined to the NW
mtns, but MVFR cig restrictions likely continue into Tue morning
over the north/west in upslope flow under building subsidence
inversion as high pressure gradually slides in from the west.
In addition, strong winds/gusts with sustained winds of 18-25 mph
and frequent surface gusts of 35-50 mph will persist through the
day, with just a slight drop off overnight - before very gradually
relaxing on Tuesday.
Outlook...
Tue...Morning MVFR cigs possible across the northern/western mtns,
otherwise gradually decreasing wind and improving conditions to
mainly VFR.
Wed...No significant weather expected.
Wed night and Thursday...MVFR to IFR conditions as periods of rain
spread east across the state. Mixed precipitation/icing possible
across the northern and western mountains of PA.
Fri...Restrictions likely N/W with scattered rain showers.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 7 PM EST this evening for PAZ019-025>028-
034>037-041-042-045-046-049>053-056>059-063>066.
&&
$$
SYNOPSIS...Fitzgerald
NEAR TERM...DeVoir/Fitzgerald
SHORT TERM...Fitzgerald
LONG TERM...Fitzgerald/La Corte
AVIATION...DeVoir/RXR
Area Forecast Discussion
National Weather Service Marquette MI
622 AM EST Mon Nov 21 2016
.SHORT TERM...(Today and tonight)
Issued at 343 AM EST MON NOV 21 2016
00Z raobs/latest wv imagery and RAP analysis show a confluent nw
flow alf over the wrn Great Lks btwn deep closed lo over New England
and an upr rdg in the Plains. Sfc hi pres under the associated deep
lyr qvector dvgc/subsidence stretches fm far nw Ontario to WI.
Despite the very dry air n of Lk Sup as shown on the 00Z YPL raob,
the nly flow/thermal trof with h85 temps as lo as -12C ahead of the
sfc hi pres rdg is causing a good deal of lo cld cover over Upr MI.
The lo clds have begun to break over the far wrn U.P. near the sfc
rdg axis and over the e as well with a shorter fetch to moisten the
upstream dry air. But considerable mid cld has moved into the w
ahead of a shrtwv riding over the upr rdg axis. Despite the
favorable thermal contrast over the relatively warm lk waters, lo
subsidence invrn base near 4k ft agl per RAP analysis and upstream
llvl dry air has resulting in no more than very light sn showers/
flurries downwind of Lk Sup.
Main fcst concerns in the short term are on cld cover/impact on
temps.
The upr rdg is fcst to amplify and shift slowly to the e, reaching
the wrn Great Lks late tngt. As this upr rdg moves to the e, so wl
the sfc hi pres rdg. The combination of lowering subsidence invrn
base/incrsg llvl acyc flow/the llvl dry air wl result in a gradual
erosion of the lingering lo clds and end any lingering light sn
showers/flurries. These clds wl be most resilient over the ncentral
with upslope nly flow/longer over water fetch. The incrsg mid lvl
subsidence wl also tend to grdly dry out the mid clds now streaming
into wrn Upr MI. Best chc for more sunshine this aftn wl be near the
WI border, allowing max temps to reach at least 32 over the scentral
with a downslope wind component. Under moclr skies/lgt winds tngt in
the presence of pwat aob 0.25 inch, tended to hedge toward the lo
end of guidance for min temps away fm the ncentral, where more lo
clds may linger. The arrival of some hi clds spilling over the upr
rdg axis late over the w may tend to hold the temps up there a bit.
.LONG TERM...(Tuesday through Sunday)
Issued at 407 AM EST MON NOV 21 2016
Mid clouds thicken on Tue but should remain dry and seasonable as
temps reach low to mid 30s and winds stay light. By far the focus of
long term is on shortwave trough crossing southern California this
morning. Trough is forecast to cross the southern plains on Tue
morning while another trough crosses farther north across the rockies
in ID and MT. Elongated sfc trough will connect the two features
early on Tue but by Tue evening, trough will consolidate into sfc low
over the central plains, vcnty of eastern KS or western MO. Ahead of
the low, a ridge of high pressure with dry air will be over the Great
Lakes. Models vary on extent of dry air which will affect how quickly
precip, in the form of snow for most cwa, moves over the Upper Great
Lakes on Tue night as the low crosses southern IA. Delayed pops over
far east cwa to account for the dry air but otherwise, advection of
deep moisture 925-500mb ahead of lead shortwave and inverted sfc
trough should support snow moving over west half of Upper Michigan.
Could see accumulations of 1-2 inches of wet snow across west third
of cwa with less than 1 inch farther into the central cwa.
Sfc low tracks across northern IL on Wed while inverted trough
extends northwest into northwest WI or even northeast MN. Widespread
precip will continue across Upper Michigan as another shortwave
trough lifts through region which enhances low-level convergence and
lift along the inverted trough. Main trend from models is to trend
upward with QPF for later in the day as main shortwave trough and h7-
h5 q-vector convergence spread across the cwa and as h85 low tracks
across western Upper Michigan. Primary question on Wed is not if
precip will occur but rather it what will ptype be - rain or snow.
Forecast soundings continue to show low wet-bulb zero heights less
than 500 ft agl so elevation and near sfc temps likely will
determine final ptype. As it looks now, only place with risk of
mainly rain throughout will be scntrl cwa as any initial snow will
give way to rain as temps quickly rise through the 30s with se winds
advecting warm air off Lk Michigan and the Bay of Green Bay. Only
place in cwa Tue night into Wed where mainly snow occurs will be the
higher terrain of west and ncntrl cwa (Watersmeet and Iron River
stretching northeast to Herman, Champion and Ishpeming). Interior
eastern cwa may also see mainly snow. Elsewhere, will be mainly
snow Tue night into Wed morning then a rain/snow mix on Wed aftn.
Total snowfall Tue night into Wed could push into the advy range
with best shot of seeing over 4 inches over the interior west and
ncntrl areas.
Into Wed night not sure how much temps will cool off as inverted
trough overhead will limit any significant cold air advection. Could
see temps in the late aftn on Wed only fall a couple degrees or stay
steady. Temps will have big impact on ptype on Wed night. Kept with
rain/snow mix most areas with greatest chance of only snow over the
interior west and ncntrl and also for the interior east were
additional snow accumulations of 1-2 inches look likely. Soundings
over the west also indicate once deeper moisture is stripped out at
temps lower than -5c late Wed night could see some drizzle or
freezing drizzle. Did not include that attm but will need to be
watched.
On Thanksgiving another shortwave trough is poised to cross cntrl
and eastern Upper Michigan. Pesky inverted trough remains in play to
provide a focus for additonal precip with the added large scale
support. Increased pops over consensus mainly from Keweenaw to
eastern cwa where low-level forcing is strongest. Ptype could still
be an issue especially in the morning. Best chance of seeing only
snow at least for the morning would be over interior east cwa.
Overall this low pressure system and widespread mixed precip will
affect one of the busiest travel days of the year and the messy
pytpe could push into Thanksgiving as well. With the messy ptype
issue and possible moderate snowfall, will issue an SPS to highlight
the hazards. Since snowfall rates do not appear to be too high at
any time during the Tue night through Wed night time frame and sfc
temps will be near or even above freezing, the main treated roads
probably will remain wet during the day on Wed. On the other hand
the snow that occurs will be a sloppier/wetter type with SLRs around
10:1 if not even lower.
Beyond Thanksgiving, rode with consensus of the models. Chance pops
still affect the area on Friday. Could see light accumulating snow
as quick moving disturbance crosses the Upper Great Lakes. General
break in wx on Sat as high pressure ridge crosses then increasing
chances for more widespread precip later Sun and/or Mon as another
low pressure system affects the region. Ptype will remain an issue
with temps expected to be a few degrees either side of the freezing
mark.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 622 AM EST MON NOV 21 2016
Expect lingering lk effect clds/MVFR cigs to impact CMX and SAW thru
this mrng in the nly flow of chilly air ahead of a slowly moving sfc
hi pres rdg. IWD is right under this rdg, so the lo clds have almost
completely dsptd there. With the dry air in place, VFR conditions
and light winds wl prevail there this fcst period. As the hi pres rdg
shifts slowly to the e, falling invrn base wl cause the lo clds to
sct out at CMX by early aftn and at SAW late in the day. VFR wx wl
continue tngt at these sites under the hi pres rdg with dry air blo
the lo invrn base.
&&
.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 343 AM EST MON NOV 21 2016
As a hi pres ridge over the western Great Lakes shifts slowly to the
e thru Tue, expect lingering n winds up to 25-30 kts over eastern
Lake Superior to diminish thru today and hold under 20 kts thru Tue.
Over the w half, light winds today and tonight will become ese and
increase to 20-25 kts on Tue/Tue night under the sharpening pres
gradient between the slowly departing hi pres and a lo pres moving
ene toward the Lower Great Lakes. These stronger ese winds will
arrive over the e by early Wed, when ese winds up to 20-30 kts will
be the rule across the entire lake. As this low moves to the e on
Thu, winds will diminish under 20 kts and back to the n-ne as a lo
pres trough lingers nearby. Winds under 20 kts on Fri will slowly
back to the w-nw ahead of an approaching hi pres ridge.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...KC
MARINE...KC
Area Forecast Discussion
National Weather Service Paducah KY
531 AM CST Mon Nov 21 2016
.SHORT TERM...(Today through Wednesday night)
Issued at 257 AM CST Mon Nov 21 2016
The pre-holiday travel period is wholly within the short term
forecast period with greater detail available for the onset of
precipitation on Tuesday.
The GFS (deterministic and ensemble) as well as the Canadian
(CMCnh) appeared to have the best overall initialization and were
overlaid on the regional model blend initialization. The initial
impact was to delay the onset of measurable precipitation into the
Southeast Missouri Foothills region until the 3pm-6pm Tuesday time
frame. There is a slight difference Tuesday Night into Wednesday
morning, as the GFS suggests a slight negative tilt to the
progressive trough across the Lower Mississippi Valley. Enhanced
(raised) PoPs a little higher than the blended guidance Tuesday
night and slightly slowed the eastward progression of higher PoPs
Wednesday morning. Similarly, maintained a differential mention of
thunderstorms longer and further east across the WFO PAH forecast
area through the remainder of Tuesday night.
Kept temperatures, dew points, and winds closer to the National
Blend model initialization with subtle changes to account for
areal collaboration. Please refer to the fire weather section on a
more detailed discussion with respect to relative humidity
concerns given existing dry vegetation around the area.
.LONG TERM...(Thursday through Monday)
Issued at 257 AM CST Mon Nov 21 2016
Overall confidence in the extended portions of the forecast is
moderate. It is fairly high through Friday and then deteriorates
over the weekend.
The 00Z models agree that there will be a fairly strong zonal flow
aloft over much of the country Thanksgiving Day through Saturday.
The flow will attempt to amplify Sunday into Monday, with ridging
over the eastern Pacific and broad troughing downstream from it over
much of the country. Unfortunately, the GFS and ECMWF do not agree
in the placement or timing of the smaller-scale systems that will
carve out the broader trough.
The 00Z ECMWF has come back into line with the GFS and its previous
runs in taking a storm system from the central Plains Thursday into
the Great Lakes on Friday. This will keep any associated
precipitation well north of the area. There will be an increase in
cloud cover as the associated cold front moves through on Friday,
but it will remain dry.
The ECMWF and GFS both develop a storm system as strong jet energy
emerges from the Rockies out onto the Plains at some point Saturday
into Sunday. The ECMWF is faster to develop this system, but both
models have at least some scattered warm advection showers over the
western half of the area beginning late Saturday night. The ECMWF
brings the bulk of the system and the cold front through the area
Sunday, while the GFS is at least 12 hours later. By the time the
GFS clears the area early Monday, the ECMWF has another system ready
to enter the western portions of the area Monday afternoon.
The bottom line is that from Saturday night through at least next
Monday, we will be in an active pattern with a couple of storm
systems likely to impact the area. Trying to pin-point which periods
will catch the brunt of the precipitation is difficult at this
point, but hopefully the ECMWF and GFS will come into better
agreement soon. The forecast will have chance PoPs over all or a
portion of the area from late Saturday night through next Monday.
The GFS and ECMWF both generate negative Showalter Indices with the
system Sunday/Sunday night, but the consensus was to leave thunder
out at this time. If I were to insert TS at this time, it would be
for Sunday afternoon and evening.
There is considerable confidence that we will be on the warm side of
whatever storm systems impact the region through this period, so we
should remain at or slightly above normal through the period, with
very little chance of any wintry precipitation.
&&
.AVIATION...
Issued at 531 AM CST Mon Nov 21 2016
A broken-overcast layer of 9kft agl ceilings, depicted better in
the 13km RAP and 00z CMCnh guidance, will transverse in and near
the KCGI and KPAH TAF locations through 14z today. Otherwise,
essentially unrestricted ceilings (actually scattered-broken 25
kft agl or higher cloud bases/ceilings) will dominate the TAF
locations beginning this afternoon and persist through the end of
the forecast period as high pressure remains across the area.
&&
.FIRE WEATHER...
Issued at 257 AM CST Mon Nov 21 2016
A survey of RAWS observations from Sunday afternoon revealed that
fuel moistures are effectively down to 8% throughout the forecast
area. This will likely only trend downward through Tuesday.
Minimum afternoon relative humidity will range from 25% to 35%
today, but winds will be light from the east or southeast. As our
next storm system approaches the area Tuesday, the low-level flow
will increase a bit from the southeast, which will actually bring
even drier air northwest into the region. As a result, minimum
relative humidity over west Kentucky, southwest Indiana and adjacent
portions of southern Illinois and southeast Missouri will range from
20% to 30% Tuesday. Once again southeast winds should be under 10
mph on Tuesday which should make any fires reasonably containable.
With dry air and dry fuels, will continue with the elevated fire
danger statement in the HWO for today and Tuesday. Hopefully, we
will get a good soaking rain Tuesday night and Wednesday, and put
the fire weather concerns out for awhile.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
SHORT TERM...Smith
LONG TERM...DRS
AVIATION...Smith
FIRE WEATHER...DRS
...Update to aviation forecast discussion...
.SHORT TERM...(Today and tonight)
Issued at 316 AM CST Mon Nov 21 2016
Upper trough axis is currently entering onshore this morning, while
midlevel moisture streams east towards the central plains. An area
of low pressure across central CO has kept winds up at 5 to 10 mph
from east southeast across northeast Kansas with lows a few degrees
warmer in the upper 20s to lower 30s.
High clouds gradually increase later today as the upper trough
progresses over the four corners region. In turn, sfc trough deepens
and pushes east into western KS, inducing southerly sfc winds from
10 to 15 mph sustained in the afternoon. The ample dry air and
warmer temps up to 9C just off the sfc on the HRRR suggest that the
stronger winds today should mix these temps down in addition to the
warm air advection from the south. The only hindrance to the warmer
temps is the overcast skies during peak heating so have not sided as
warm as the HRRR, but closer to the GFS mos guidance in the middle
to upper 50s for highs. Tonight, mid level moisture gradually
advects northward as a lead vorticity maximum ejects toward Nebraska
and central Kansas after midnight. Forecast soundings across the
area suggest saturation may not be adequate for rain showers until
sunrise Tuesday. Have best chances for precipitation closer to the
maximum lift over north central areas, increasing to a chance of
showers elsewhere after 3 am. There is less than 100 J/KG of mixed
layer cape so I mentioned a slight chance for thunder, but overall
scattered rain showers are the primary precip type.
.LONG TERM...(Tuesday through Sunday)
Issued at 316 AM CST Mon Nov 21 2016
Showers and thunderstorms look likely for Tuesday morning as the
shortwave passes across the forecast area. Models show the
strongest forcing to impact the area through the morning with the
dry slot working its way across central and into eastern KS
during the afternoon. Lapse rates should be steep enough for some
thunder with the showers, although models have trended to
advecting a stratus deck north ahead of the forcing which would
limit insolation and destabilization. Because of this think
thunderstorms will tend to be more isolated due to limited
instability. There may also be a brief period of wrap around
precip Tuesday evening before the system moves east and dry air
advects in from the northwest. It continues to look like the
precip will come to an end before the cold air arrives so there
is not much concern for frozen precip. Models overall are still
not that impressed with precip amounts in spite of PWs increasing
to around 1 inch, which for this time of year is pretty moist. I
suspect the reason is an inversion capping the boundary layer with
no real good source of lift. Nevertheless there should be more
than enough large scale forcing that most areas should see some
rain. Given the progressive nature of the system, amounts around a
quarter of an inch appear to be plausible. With the expected cloud
cover limiting sunshine, have cooled the forecast highs for
Tuesday a couple degrees.
Wednesday and Wednesday night continue to appear dry with
shortwave ridging overhead. Although another progressive shortwave
is anticipated to move overhead late in the day Thursday and
Thursday evening. Models have trended further south with the
better forcing from this wave. However moisture continues to be a
big limiting factor regarding precip chances. The GFS shows a lot
less moisture advection ahead of this wave due to surface ridging
along the TX gulf coast. Model blends have inserted a low POP
across far northeast KS Thursday evening as the wave passes. Have
kept some slight chance POPs for collaboration, but given the
limited moisture think this may be generous.
Confidence in the forecast becomes a little lower by the weekend
as the ECMWF and GFS have been inconsistent in the shortwave
details beyond 132 hours. There remains signs for another wave to
dig through the central Rockies and lift out through the plains.
But models have trended to keep this feature west of the forecast
area until Sunday or possibly Monday. The GFS ensemble members
show the shortwave anywhere from the central plains to southern CA
at 12Z Sunday. So the forecast is a blend of available guidance
which has some slight chances for Sunday. The details of the
forecast area likely to change as the forecast gets closer in
time.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 511 AM CST Mon Nov 21 2016
VFR conditions persist while light southeast winds increase above
10 kts aft 20Z at KMHK and between 00Z and 05Z at KTOP and KFOE.
Incoming storm system brings higher confidence for showers at KMHK
aft 10Z with MVFR ceilings moving in. Rain may impact categories
at KTOP and KFOE aft 12Z Tuesday.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Prieto
LONG TERM...Wolters
AVIATION...Prieto
Area Forecast Discussion
National Weather Service Denver/Boulder CO
227 PM MST Mon Nov 21 2016
.SHORT TERM...(This evening through Tuesday)
Issued at 227 PM MST Mon Nov 21 2016
Satellite imagery showing the center of the upper level trough is
moving into the Great Basin and Desert Southwest. It will
continue track east-northeast tonight and Tuesday. Scattered
showers are expected to spread east into the central and north
central mountains later this afternoon and evening. Latest HRRR
and RAP has backed off on the amount of showers, but still show
some. A few locations may see a quick inch or two snow if a heavy
snow shower passes over.
Snow should become widespread over the mountains around midnight as
the trough tracks over Colorado. Rain showers are expected to move
onto the Front Range and eastern plains shortly after midnight.
Airmass will be warm enough that precipitation will begin as rain at
the lower elevations. Eventually colder air moves in and a rain/snow
mix is expected around 12z with a brief period snow possible as
well. A heavier band of precipitation is expected to form on the
back side of the low Tuesday morning. Precipitation may turn to all
snow under this band with a few inches possible. Most of the GFS
ensemble members and ECMWF has this band to the east of the forecast
area. Will go with snow accumulation of around an inch over parts of
the eastern plains for this.
A moist northwest flow over the mountains is expected to keep snow
going through the morning. Most of the snow accumulation could occur
late tonight and Tuesday morning. Will keep the Winter Weather
Advisory in effect through Tuesday afternoon. As drier air moves in,
snow will decrease Tuesday afternoon. Precipitation will come to an
end mid to late morning along the Front Range as this system
continues to shift east. The precipitation may linger into the
early afternoon across the eastern plains.
.LONG TERM...(Tuesday night through Monday)
Issued at 227 PM MST Mon Nov 21 2016
Moisture and large scale forcing quickly diminishes Tue eve as
the upper trough moves out over the central Great Plains. Brisk
n-nwly deep layer flow and cold air advection continue overnight
giving us a colder night...although min temps by morning still
near to slightly above avg for the date. on Wed...an upper air
ridge is progged to pass over the region returning dry and warmer
conditions. Projected max temps on wednesday 1-3 deg c above
average with lower 50s on the plains with plenty of sunshine.
Warmup on the plains also aided by a warm sly breeze for much of
the day. by Wed night...models show the bottom side of an open
mid-level shortwave trough brushing over northern Colorado. system
appears wetter and more amplified on the GFS and DGEX...while the
Canadian model keeps the bulk of the moisture and energy with
this system up over Wyoming. Because of the most certain jump in
high country travel for the holiday...will trend the Wed night/Thu
fcsts towards the wetter/snowier GFS and DGEX and go with likely
pops over the higher elevations. By Thu afternoon could see
anywhere from 2-5 inches in the mtns...with high amounts on the
north and west slopes. However...the Park Range roughly north of
Rabbit Ears pass could possibly see totals approaching 8 inches on
a localized basis. There will be some wind...but with relatively
warm temperatures...do not see much in the way of blowing snow.
Most models show the wave swinging out over the plains
Thanksgiving Day with little more than a few light rain or
rain/snow showers across the nern corner of the CWA. Nwly flow
downsloping off the Front Range should hinder the formation of
precip within the urban corridor...except perhaps up near the
Wyoming border in the morning where any qpf should be minor at
best.
Thursday night through Saturday morning models show the forecast
area under the drying and warming effects of a flat upper
ridge. Should see slight warming both days with highs anywhere
from 4-7 degs above average. FYI...avg high at Denver during this
period is around 47.
Sunday and beyond...forecast less certain with model guidance
offering different times for the passage of another upper trough.
European model shows the trough and its precip over our eastern
border by Sunday morning. The GFS...DGEX and Canadian models show
the trough just arriving in western Colorado by that time. The
GFS and DGEX swinging this system across the state during the day
and out of the state by late that evening. Unfortunately the
Canadian model does go out that far. However...the European model
races another wave down across the nern Great Basin on Sunday...
and then across Colorado Sunday night and Monday. Because of the
uncertainly in the models out that far...will go with low pops for
Sunday/Sunday night and no pops for Monday...at least for now.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 227 PM MST Mon Nov 21 2016
A surface low deepening over southeast Colorado will cause winds
to turn northerly around or just after 00z. Northerly winds will
continue tonight and Tuesday. Gusts up to 30 knots will be
possible Tuesday morning. Scatter rain showers will be possible
after 00z. This could briefly drop ceilings to 6000 feet. Showers
will increase after 06z with the best chance for showers 09-15z.
Precipitation will start off as rain. A mix or a brief change over
to snow is expected around or after 12z. Right now it appears
snow accumulation will be light and less than an inch. There is
about a 25 percent chance at seeing an inch or more. Ceilings
could fall below 1000 feet with visibility less than a mile if
precipitation turns to all snow. Conditions will start to improve
around 16z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 5 PM this afternoon to 5 PM MST
Tuesday for COZ031-033-034.
&&
$$
SHORT TERM...Meier
LONG TERM...Baker
AVIATION...Meier
Area Forecast Discussion
National Weather Service State College PA
351 PM EST Mon Nov 21 2016
.SYNOPSIS...
Windy conditions will persist through tonight as a large upper
low over New England slowly lifts northeast toward the Canadian
maritimes. Weakening low pressure lifting out of the Mississippi
Valley will likely track just north of Pennsylvania by midweek...
bringing moderating temperatures and a chance of rain showers
Wednesday night and Thursday. Mixed precipitation will be possible
across northern portions. Another cold front will cross the
commonwealth Friday night and Saturday...delivering another brief
punch cold air.
&&
.NEAR TERM /THROUGH TONIGHT/...
Inversion heights remain around 7k feet maintaining lake effect
snow flurries across the Laurel Highlands...West Central and
Northwest Mountains. Accums if any are light...and the bigger
story remains the wind across central and eastern PA
especially...where gusts have eclipsed 40 mph in some spots.
Slowly diminishing wind will occur tonight as brisk and deeply
channeled northwest flow persists overhead. Won`t see significant
improvement in the wind until later on in the daytime Tuesday in
fact.
Inversion heights are just shy of 7k feet this afternoon...and
lower sufficiently after midnight for flurries and snow showers to
diminish. Carrying additional accums less than one inch from the
West Central and Northwest Mountains. Latest HRRR in agreement
with this thinking...and continues to even hint at a weak Lake
Huron band persisting into the pre dawn hours Tuesday morning.
Well mixed boundary layer tonight with fairly uniform mins ranging
from the mid 20s northwest to around 30F southeast.
&&
.SHORT TERM /TUESDAY/...
Surface ridge builds into the state on Tuesday...allowing
inversion heights to continue to fall. Any lingering flurries and
snow showers will end by afternoon as 1028 mb ridge builds through
Ohio. This will bring brightening skies and a more pleasant
afternoon...although it will remain breezy. Highs will range from
the mid 30s north to the mid 40s southeast.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
High pressure will build in for Tuesday night and early Wednesday
before we begin to be affected by the warm air advection ahead of
the next approaching frontal system.
Precipitation type issues could arise as the precipitation
associated with the frontal system begins to move into the region
with air and wet bulb temperatures aloft that will be marginally
cold over about the northern half or so of the forecast area. I
inserted the mention of pockets of freezing rain or sleet
Wednesday night into early Thursday morning with surface
temperatures dropping to freezing in some of the northern normal
cold spots. It doesn`t look like a big QPF event but things could
potentially get slippery for a time when holiday travel will be
ramping up.
The 12Z GFS/ECMWF both weaken the cold/occluded front as it
enters the state Thanksgiving Day in favor of a new low that they
form along or just off the eastern seaboard. This low gradually
deepens into a single strong ocean storm over the coastal waters
east of New England Friday night and Saturday. With at least a
pair of upper shortwaves responsible for these developments
slated to push through, it looks good for us to stay unsettled
right through Saturday before a ridge can replace the cyclonic NW
flow aloft and bring drying conditions for the second half of the
weekend.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
Snow showers and flurries have diminished in intensity...but will
persist in upslope locations of the Laurel Highlands...West
Central and North Central Mountains through tonight into Tuesday
morning...producing local MVFR restrictions. Strong winds/gusts
with sustained winds of 18-25 mph and frequent surface gusts of
35-50 mph will persist into this evening...with just a slight
drop off overnight - before very gradually relaxing on Tuesday as
high pressure builds eastward across the region.
Outlook...
Wed...No significant weather expected.
Wed night and Thursday...MVFR to IFR conditions as periods of rain
spread east across the state. Mixed precipitation/icing possible
across the northern and western mountains of PA.
Fri...Restrictions likely N/W with scattered rain showers.
Sat...Restrictions possible N/W with scattered snow showers.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 7 PM EST this evening for PAZ019-025>028-
034>037-041-042-045-046-049>053-056>059-063>066.
&&
$$
SYNOPSIS...DeVoir
NEAR TERM...DeVoir
SHORT TERM...DeVoir
LONG TERM...Fitzgerald/La Corte
AVIATION...DeVoir/RXR
Area Forecast Discussion
National Weather Service Grand Rapids MI
304 PM EST Mon Nov 21 2016
LATEST UPDATE...
Synopsis/Short Term/Long Term/Marine
.SYNOPSIS...
Issued at 304 PM EST Mon Nov 21 2016
Quiet weather will continue through Tuesday evening across Southwest
Michigan. However a wintry mix will develop late Tuesday night.
This mix will continue on Wednesday north of I-96, while the
precipitation changes to plain rain to the south. Holiday travel
may be impacted with slower than normal driving speeds Wednesday
over Central Lower and points north. The mixed precipitation is
expected to slowly change to more rain over Central Lower Wednesday
afternoon and night.
Thanksgiving Day is expected to be a quiet weather day, then more
rain returns for Friday. Another good chance of rain returns Sunday
night into Monday.
After daytime temperatures only in the mid 30s to around 40 Tuesday
and Wednesday, we should be slightly warmer for the Holiday weekend
with highs mainly 45 to 50.
&&
.SHORT TERM...(This evening through Wednesday night)
Issued at 304 PM EST Mon Nov 21 2016
Concern remains for a messy mix starting everywhere late Tuesday
night, and perhaps lasting into Wednesday night for the interior
north.
Low pressure near Kansas City Tuesday night will move toward Central
Lower by late Wednesday night. While Southern Lower will warm by
early Wednesday to change any pcpn to rain, Central Lower remains
cold enough to be concerned for an extended period of mixed pcpn.
Better agreement in the models today with the temp regime, at least
into Tuesday night/early Wednesday. Then differences appear Wed
afternoon into Wed night, as the exact track of the surface low will
impact temp trends, especially across Central Lower.
The initial wave of pcpn late Tuesday night should largely be
freezing rain, that may mix with snow north/rain south. We continue
to see a warm layer aloft on forecast soundings as the deeper
moisture arrives, along with shallow cold air near the surface. The
freezing rain should be fairly brief in most areas, but it may put
down a light glaze on elevated surfaces, such as tree limbs and car
tops, etc..
Travel concerns may be realized by Wed north of I-96 where the mixed
bag may continue much of the day. Again this will depend on the
low`s track. But as of now it appears the warm layer aloft is
eroded and the pcpn becomes snow and sleet, then sleet and rain into
Wed night. We will continue to deal with a warm ground, but the
persistence of the pcpn could cause slushy roads. Overall the snow
and sleet appears to be an inch or less, but enough to make sloppy
roads. Along and south of I-96 the pcpn should largely be a chilly
rain, that may mix with some snow Wed morning.
Until then, quiet weather continues through Tuesday evening. Low
tonight in the 20s, with a high on Tuesday around 40.
.LONG TERM...(Thursday through Monday)
Issued at 304 PM EST Mon Nov 21 2016
Active weather pattern will produce several chances for
precipitation during the extended period...with precipitation type
the main concern.
Precipitation will be ending from west to east early Thursday...with
a second system quickly on its heels. Thicknesses suggest
snow...but with temperatures rising to near 40...it will likely end
up as a mix.
Stronger storm system moves through the region late Sunday into
Monday...deepening as it passes just to our west. While the system
should produce rain initially...expect it to end as snow as colder
air spills in from the west.
Temperatures should be close to seasonal norms...with highs around
40 and lows around 30 each day. Slightly warmer temperatures are
expected late Sunday into Monday as warm air surges north ahead of
stronger system.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1220 PM EST Mon Nov 21 2016
Satellite indicates erosion of cloud cover across Michigan...with
KBTL scattering out in the last hour. Greatest coverage indicated
around KMKG but breaks are developing there as well. Expect
clearing to continue this afternoon as drier air moves in with
the surface high pressure area and onshore winds ease. Forecast
soundings from HRRR suggest fog may develop overnight under a
clear sky and with lighter winds...but expect visibilities to
remain VFR and will not include it in the TAFs at this time.
Clouds will spread back into the region Tuesday afternoon ahead of
the next storm system.
&&
.MARINE...
Issued at 304 PM EST Mon Nov 21 2016
We are allowing the small craft advisory to expire as of 4 PM. A
short period of calmer conditions will prevail tonight and Tuesday
with high pressure passing through. We may need another small craft
advisory north of Grand Haven late Tuesday night into Wednesday with
the approach of the next system.
&&
.HYDROLOGY...
Issued at 1214 PM EST Mon Nov 21 2016
There is little or no concern for flooding over the next several
days. Many rivers are running near normal with few exceptions. A
more active pattern is anticipated to set in from late Tuesday
through next weekend. Precipitation amounts through the middle of
the week have been lowered since yesterday and seven day totals
should be easily managed by rivers.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&
$$
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...MWS
AVIATION...MWS
HYDROLOGY...JAM
MARINE...JK
Area Forecast Discussion
National Weather Service Marquette MI
357 PM EST Mon Nov 21 2016
.SHORT TERM...(This evening through Tuesday)
Issued at 337 PM EST MON NOV 21 2016
Water vapor imagery and RAP analysis show a deep closed low centered
just n of New England. To the w, a ridge extends n thru the Plains
with associated sfc high pres ridge extending from western Hudson
Bay s across western Lake Superior and WI. Dry air, low inversion
and lack of much overwater fetch has resulted in the skies becoming
sunny across western Upper MI today. Continued northerly flow across
eastern Lake Superior ahead of the sfc high pres ridge axis is
maintaining stratocu into the e half of the fcst area.
Axis of sfc high pres ridge will very slowly drift e tonight, only
reaching a line from roughly Copper Harbor to Iron Mtn by 12z Tue.
This will maintain a northerly flow into the eastern fcst area thru
the night, suggesting sct-bkn even ovc stratocu may hold on thru the
night. Moderating 850mb temps from around -10C now to around -5C by
morning will cut down on the cloud cover, but band of
moisture/stratocu per vis satellite imagery n and ne of Lake
Superior will probably work to maintain greater coverage as this
moisture advects s/ssw. Clouds will help keep temps up over the e,
probably mid/upper teens well inland to mid 20s along Lake Superior.
To the w, with calm wind under sfc high pres ridge, clear skies thru
the evening and precipitable water aob 0.25 inches, favored the low
side of avbl guidance. High clouds will probably begin to increase
overnight, preventing ideal radiational cooling all night. While
traditional cold spots will fall just under 10F, certainly not of
the question for a few locations with a decent snow cover to plummet
toward 5F, perhaps lower. Coldest spots in ne MN last night were
around 5F.
Shortwave trof moving across the western CONUS currently will shift
out over the western Plains on Tue while mid level ridge shifts to
Upper MI. Although isentropic ascent begins to increase into far
western Upper MI late in the day ahead of the trof, fcst soundings
show a significant amount of low-level dry air that will need to be
overcome. Given the overall weak forcing, it`s unlikely that any
-sn will reach the KIWD area before 00z Wed. Otherwise, expect an
increase in high and mid clouds w and central thru the day. E may
end up mostly sunny for much of the day. High temps should be mostly
in the low/mid 30s.
.LONG TERM...(Tuesday night through Monday)
Issued at 357 PM EST MON NOV 21 2016
Main weather concern during this forecast period will be the
potential for snow, possibly advisory level, moving into the area
late Tuesday night through Wednesday night. This will likely cause
slippery Thanksgiving travel across the area south and westward into
WI and MN.
Tuesday night through Wednesday night: A surface low is progged to
be centered over northwest Missouri Tuesday evening before shifting
northeastward into Lower Michigan Wednesday night. Aloft, a trough
of low pressure will slide from the Plains eastward into the Great
Lakes region as it tries to becomes negatively tilted through the
same time period. Initially, fairly dry are will be in place across
the area, as a brief ridge slides through, which should keep most of
the precipitation out of the U.P. until the overnight hours Tuesday
night for the western U.P. Much of the central and east may end up
staying dry Tuesday night. Deeper moisture will be advected into the
area ahead of the low. This will sufficiently moisten the atmosphere
across the area to allow most of the U.P. to see precipitation. The
best/deeper forcing with this system will slide across the area
Wednesday afternoon into Wednesday evening as shown by overlaying
1000-500 RH and deep layer Q-Conv; however, a shortwave is progged
to slide through the area late Tuesday night into Wednesday morning,
which may help to enhance snow during that period as well. Overall
precip type will be mainly snow across the entire U.P.; however, the
far south-central locations and areas close to the Great Lakes may
see a bit of rain mix in during the day Wednesday. Otherwise, wet
bulb temps are progged to remain near or just below freezing through
the profile, except over far south central areas where the surface
temps and low level warm air may mix the snow with rain. The DGZ is
in a fairly shallow layer above the best forcing. This, coupled with
near freezing surface temps, will keep the snow ratios in check.
Overall, not really expecting to see overly impressive snowfall
totals; however, the slower movement of the system will allow the
system to produce advisory level snow, mainly over the western half
of the U.P. Generally expecting between 0.2 and 0.4 tenths of an
inch of liquid, which would equate to about 2 to 5 inches of snow
over the west half and around 1 to 2 inches over the east half with
a roughly 10:1 snow to liquid ratio. At this point, will stick with
a SPS to highlight the potential for the high moisture content snow,
which will make Thanksgiving travel plans slippery at times.
Thursday through Friday: Another surface low and 500mb wave will is
progged to slide through the Upper Great Lakes Thursday night into
Friday, which will keep a chance of rain and snow in the forecast,
although the precipitation should be much lighter. Moisture looks to
be fairly shallow overall through much of Thursday night which may
end up giving drizzle or flurries through that time period, with a
transition to more of an actual rain/snow mixture Friday.
Temperatures will be a bit warmer during this time period with highs
in the mid 30s and overnight lows in the mid 20s to around 30.
Saturday through the extended: High pressure and dry air are progged
to slide across the area Saturday and Saturday night, which allow
for a break in the precipitation. Beyond that time period, models
begin to diverge significantly, with the GFS keeping dry air and a
ridge in place while the EC slides a closed low and upper trough
through the Great Lakes. At this point, will stick with a consensus
blend of the models.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1227 PM EST MON NOV 21 2016
High pres over western Lake Superior/far western Upper MI will
slowly shift e, only reaching central Upper MI by early Tue aftn.
With the ridge drifting e of KIWD and a dry air mass now in place,
VFR conditions will prevail at KIWD thru this fcst period. KCMX will
also be VFR thru the fcst period, but as the ridge shifts e of the
terminal, developing upslope ese wind off Lake Superior could lead
to a brief period of bkn MVFR cigs mid to late Tue morning. At KSAW,
moderating air mass and lowering inversion will cause lingering lake
effect clouds/MVFR cigs to scatter out later this aftn/evening.
However, not out the question that bkn MVFR cigs could occur at times
thru tonight as light upslope n to ne winds continue until the high
pres ridge arrives late Tue morning.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 337 PM EST MON NOV 21 2016
As a high pres ridge extending s across western Lake Superior drifts
e, reaching eastern Lake Superior Tue aftn, lingering 20-25kt winds
over eastern Lake Superior will diminish, falling blo 20kt overnight
and blo 15kt for Tue. Over the w half of the lake, winds will remain
mostly under 15kt tonight/Tue, but will increase slightly Tue aftn.
As the ridge shifts e and a low pres system emerging over the Plains
early Tue tracks ene into the western Great Lakes by Wed evening,
ese winds will increase up to 20-25kt across much of the lake Tue
night into Wed with the strongest winds occurring over central and
eastern Lake Superior. Winds will then diminish to under 15kt for
Thu-Fri as the pres gradient across the area becomes weak. Winds
will begin to increase again later Sat as a high pres ridge over the
western Great Lakes early Sat shifts e during the day.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...KEC
AVIATION...Rolfson
MARINE...Rolfson