Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/10/19
Area Forecast Discussion
National Weather Service Green Bay WI
532 PM CST Sat Feb 9 2019
Updated aviation portion for 00Z TAF issuance
.SHORT TERM...Tonight and Sunday
Issued at 242 PM CST Sat Feb 9 2019
The latest RAP analysis and satellite/radar imagery show a 1045mb
high pressure system centered across the Great Lakes early this
afternoon. Mid and high clouds are increasing from the west ahead
of a weak shortwave and associated warm advection occurring over
the northern Plains. A more potent shortwave is moving east over
southern California, which will be the system to impact the region
on Sunday. Snow accumulations and potential impacts are the main
forecast concerns in this period.
Tonight...The shortwave currently over the northern Plains will
shear apart as it moves across the northern Great Lakes. It will
bring a chance of light snow with it, but models project the
snowfall should remain north of the U.P. border. Otherwise, the
jet stream will continue to push mid and high clouds overhead.
Clouds should become thicker through the night, but with high
pressure and light winds across the region, any clearing would
promote tanking temps. Dropped temps slightly at the cold spots
over north-central WI. Lows ranging from 5 below across the north
to the upper single digits over east-central WI.
Sunday...The potent desert SW shortwave trough will move
northeast across the central Plains and into Wisconsin, and shear
apart slightly in the process. As the shortwave draws closer,
isentropic ascent and mid-level fgen will increase across the
state. Some of the higher resolution models indicate a band of
snow will develop and push east across central to northeast WI during
the morning before expanding rapidly across the area around
midday. It appears the strongest forcing will reside downstate
during the afternoon. But widespread qpf amounts of 0.1-0.2 inches
appear likely over central to east-central WI in the afternoon.
With high snow to liquid ratios, accumulations of 3-4 inches
appear possible south of a Tomahawk to Sister Bay line. Locally
higher amounts are possible near the Lake Michigan shoreline,
where light onshore flow will occur for much of the event. With
coordination from surrounding offices, will issue a winter weather
advisory starting in the 12-15z period. Highs warming into the
mid-teens to mid 20s.
.LONG TERM...Sunday Night Through Saturday
Issued at 242 PM CST Sat Feb 9 2019
Very active pattern setting up for next week with several bouts of
winter weather to deal with. Temperatures will fluctuate from a
few degrees below/above normal as each system passes through the
Great Lakes.
Light snow will be ongoing/ending Sunday evening as the weak
shortwave shears out and exits the area. Additional accumulations
should be pretty minor (up to around 1" for most spots). Could
see the snow linger a little longer and have some higher totals
near Lake Michigan, especially the farther north you go, due to
lake effect/enhancement as 850 mb temp hover between -11C and
-15C. One thing to keep an eye on will be the mid-level drying
that takes place Sunday night into Monday morning. Looks like
eastern WI will lose ice crystals generation so a transition to
freezing drizzle is possible. Question will be whether the depth
of moisture will be sufficient to have drizzle occur or it will
just be dry.
Monday looks dry for most of the area, but some lingering drizzle
or flurries are possible, mainly across eastern WI, with a little
moisture aid from Lake Michigan. With all the lingering moisture
below 850 mb, it will be a challenge to see much sunshine. High
temps look to be mainly in the 20s.
Attention then turns to the next storm which will bring another
round of wintry weather to the area Monday night into Tuesday
night and early Wednesday morning. This system is still being
handled differently by the models, especially the Canadian which
is weaker and farther south. GFS/ECMWF still show a healthier/
wrapped up system, bringing significant impacts to the area with
accumulating snow (6+ for many spots), along with blowing and
drifting snow. The amount of blowing snow will hinge on just how
wrapped up the system gets. Will lean the forecast to the heavier
amounts with an advisory/warning type event looking very likely.
There could be a little freezing drizzle at the onset of the storm
Monday evening, but saturation occurs quickly and a change over
to snow will happen quickly. As the system exits, the snow will
wrap up late Tuesday night into early Wednesday morning. Snow will
linger the longest across north central WI where lake effect snow
showers will continue into Wednesday.
As winds veer Wednesday afternoon and evening, the lake effect
will shut off and dry weather is expected across the area
Wednesday night. The quiet weather will be short- lived as the
next winter system arrives on Thursday. Models have shifted a
little south with this storm, so the area might miss out of the
brunt of this system, but there is plenty of time for this system
to change its track.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 532 PM CST Sat Feb 9 2019
Good flying weather expected tonight with middle and
high clouds and light surface winds. Snow still looks set to
arrive Sunday morning and then linger through late afternoon or
early evening. A few inches of snow are possible, which will lead
to lower ceilings and visibilities, likely in the MVFR to IFR
range.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 9 AM Sunday to midnight CST Sunday
night for WIZ019>022-031-037>040-045-048>050-073-074.
Winter Weather Advisory from 6 AM to 9 PM CST Sunday for WIZ018-
030-035-036.
&&
$$
SHORT TERM.....MPC
LONG TERM......Bersch
AVIATION.......Cooley
Area Forecast Discussion
National Weather Service Marquette MI
616 PM EST Sat Feb 9 2019
.SHORT TERM...(This evening through Sunday)
Issued at 359 PM EST SAT FEB 9 2019
WV imagery and RAP analysis indicated confluent zonal mid/upper
level flow between a deep mid level trough over northeast Canada and
a ridge over the se CONUS. At the surface, calm or light westerly
winds prevailed as a 1044 mb ridge builds into the area. A weak
shortwave trough into nrn MN supported mainly mid and high clouds
along with a few flurries.
Tonight, the weak shortwave will streak across the northern Great
Lakes. There may be some light snow or flurries ove mainly the west
and north if the low-level dry air can be overcome. The shrtwv may
also support an increase in light west flow LES. However, inversion
heights only to around 3k ft and substantial ice cover should limit
any amounts to under an inch.
Sunday, the models were in better agreement in bringing snow
northward supported by 280k-290k isentropic lift. However, the
associated 850-600 mb fgen circulation will maintain dry low level
north to northeast flow that will result in a sharp northern
boundary to the pcpn. So, likely POPs were mentioned south with
chance north due to uncertainty with the nrn extent of the snow. 1-3
inch amounts may be possible toward MNM with around an inch or less
closer to US-2, and less than an inch over the north.
.LONG TERM...(Sunday night through Saturday)
Issued at 354 PM EST SAT FEB 9 2019
With fairly benign weather otherwise, attention is on a potential
storm system late Mon night through Tue.
GFS/ECMWF/NAM agree fairly well on the system, and have been pretty
consistent run to run, with showing a shortwave moving through the
region along with the associated surface low moving through Lower
MI. The ECMWF is about 6 hours slower than the GFS and NAM, but
otherwise agrees well. This resulting in snow moving in from the S
late Tue night and mostly moving out by 06Z Wed, with only lake
effect snow continuing after that. Gusty NE winds will lead to
lake/upslope enhancement over the N-central and also blowing snow in
areas near Lake Superior exposed to E and NE winds. The central and
eastern U.P. are expected to see the most snow, with potential for
around 6" total. NW and W Upper MI should be closer to 3-6". Much of
that snow falls in a roughly 8 hour period Tue, potentially falling
heavily at times. Will be watching things closely as we continue to
refine the forecast with future model runs. Also, could see some
light flurries or freezing drizzle over the S-central for a few
hours preceding the synoptic snow, but do not expect many impacts
from that at this time.
There is potential for another storm system late in the week, but
confidence is very low given significant model disagreement.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 616 PM EST SAT FEB 9 2019
VFR conditions are expected to prevail until Sun afternoon for IWD
when a weak system comes in and brings in some IFR/MVFR conditions.
At KCMX, VFR conditions will last through this evening. Otherwise,
MVFR cigs will likely prevail with -shsn/flurries at times under
continued westerly winds off Lake Superior. At KSAW, VFR conditions
will set back in this evening and last into Sun afternoon before
MVFR conditions move in with the next weather system.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 359 PM EST SAT FEB 9 2019
A low pres system lifting from the southern Plains to the Great
Lakes region next week may bring a period of e to ne winds of 30
to 35 knots on Tue.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Heavy Freezing Spray Warning until 7 PM EST this evening for
LSZ249>251-266-267.
Heavy Freezing Spray Warning until 1 AM EST /midnight CST/
Monday for LSZ162-240>244-263-264.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...Titus
AVIATION...07
MARINE...JLB
Area Forecast Discussion
National Weather Service Omaha/Valley NE
933 PM CST Sat Feb 9 2019
.UPDATE...
Issued at 930 PM CST Sat Feb 9 2019
There is a large variation in model output in regards to precip
amounts overnight through Sunday morning. The NAM12 is the most
bullish with amounts 06z to 12z across eastern NE and southwest IA
(it has the highest values). It is much higher than any other
recent model output, including the SREF, HRRR and RAP13. The 00z
GFS is drier between Lincoln and Omaha than the NAM, putting its
heaviest QPF overnight in western IA. Will stay pretty close to
the previous forecast with minor adjustments.
00z upper air maps indicated 12 hour height falls of 50-70 meters
at 500 mb back over the Four Corners region and a 300 mb jet
streak of around 130 kts. This will help generate a short period
of strong lift later tonight.
UPDATE Issued at 520 PM CST Sat Feb 9 2019
Expect potential snow amounts of about 1 to 3 inches for much of
the forecast area for tonight, highest amounts north and northeast
of Omaha. Amounts around an inch or less expected in the far
western and southern parts of the forecast area.
For Monday and Monday night, amounts could be up to 3 or 4 inches
with the highest amounts, at this time, expected in western IA
and the northern parts of northeast NE.
&&
.SHORT TERM...(Tonight through Tuesday)
Issued at 300 PM CST Sat Feb 9 2019
Accumulating snow will be possible tonight through Sunday
morning. All this in part to a minor shortwave trof ejecting out
of the four- corners region and lifting toward the Dakotas.
Expect snow to develop around midnight as ascent/mid layer
ageostrophic forcing within area of stout 290-300k isentropic
upglide. Short term models are in decent agreement moist
dendritic omega will be most prevalent over the IA CWA.
Sunday night a more complicated precip scenario setting up with a
mix of liquid/freezing/frozen across eastern NE and southwest IA
through late Monday night. Once again moist dendritic omega will
be most prevalent over the IA CWA.
.LONG TERM...(Tuesday night through Saturday)
Issued at 300 PM CST Sat Feb 9 2019
Pacific NW wave drops into the central Rockies Thursday afternoon
and strengthens as it pushes into the central Plains Thursday
evening. ECM and CMC prefer a more southern track through OK.
Meanwhile the GFS shows the system crossing across KS. At any rate,
increasing DPVA induces surface cyclogenesis along the CO/KS
border with precipitation forming just north of the deepening
system. As the surface low lifts across the mid MS valley region,
precipitation is progged to expand mainly across the eastern
portion of the CWA Thursday afternoon into early Friday morning.
Cold conditions over most of the CWA Wednesday and Thursday with
well below normal highs generally in the low/mid 20s north of I-80,
and mid 30s/low 40s south of I-80.
On Friday and Saturday, entire CWA cold with highs only in the mid
teens/low 20s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 520 PM CST Sat Feb 9 2019
Expect deteriorating conditions for tonight, especially after
midnight. Conditions should drop to IFR with both ceilings and
visibilities with light snow. Expect conditions to improve a bit
at least for visibilities as snow ends late morning or early
afternoon.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
UPDATE...Miller
SHORT TERM...DEE
LONG TERM...DEE
AVIATION...Miller
Area Forecast Discussion
National Weather Service Tucson AZ
858 PM MST Sat Feb 9 2019
.SYNOPSIS...A few sprinkles are possible for southeastern Arizona
tonight. Isolated showers are expected on Sunday mainly south and
east of Tucson, and mainly northeast of Tucson on Monday. Otherwise,
dry conditions through Wednesday. There will then be a chance of
valley rain and mountain next Wednesday night through Friday, as a
stronger storm system moves through the region. Expect cooler
temperatures Sunday into Monday. Warmer temperatures return by the
middle of next week.
&&
.DISCUSSION...Cloudy skies across southeast Arizona this evening
under southwesterly flow aloft. 00Z KTWC sounding shows the story
very well with plenty of moisture above about 600 mb with a very dry
sub-cloud layer and a 0.30 inch PWAT. Clouds are expected to persist
overnight and given the widespread virga currently showing up on the
KEMX radar, we can`t rule out a few sprinkles as well, especially in
the higher terrain. A quick look at the 00Z NAM and latest HRRR
continue to show the potential for some light showers Sunday across
portions of Cochise County. This is handled well in the ongoing
forecast. Only minor tweaks for the overnight period to account for
current trends. Otherwise, the forecast was left as is.
&&
.AVIATION...Valid through 11/06Z.
SCT-BKN clouds above 12k-14k ft AGL with another layer of BKN-OVC
clouds AOA 20k ft AGL through the evening. Overnight through Sunday
cigs lower to 10k-14k ft AGL at KOLS and KDUG and remain AOA 20k ft
AGL at KTUS. Winds will be gusty this afternoon out of the southwest
at 10-15 kts with gusts up to 25 kts. This evening and Sunday night
winds drop below 8 kts then become gusty out of the southwest again
Sunday afternoon. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Slight chance of sprinkles this afternoon then a
slight chance for showers mainly in Cochise County Sunday. Monday
morning into the afternoon precip chances move to the White
Mountains. After a brief lull, a more expansive weather system
brings a chance of widespread showers later on Wednesday continuing
into early Friday morning. 20-ft winds breezy this afternoon and on
Sunday out of the southwest reaching 10-20 mph. These breezes return
by midweek with the arrival of the next weather system.
&&
.PREV DISCUSSION...Only made minor tweaks for this afternoon and
evening. Expanded the slight chance of sprinkles west into Tucson
Metro and then gradually drying out through the late afternoon and
into the evening. Enough afternoon mixing has allowed surface winds
to increase, thus causing dew points to crash as dry air mixes to
the surface. This was most recently seen across the western portions
of the Tucson Metro as winds picked up, dew points dropped by 20
degrees. This should help curb any moisture making it to the ground,
outside of the highest peaks.
Winds are finally increasing across the Tucson Metro, with wind
gusts 10-20 mph and 20-30 mph across the west side of town. Winds
have also been breezy across the White Mtns and from Nogales east to
Sierra Vista, where gusts have been in the 20-35 mph range. Winds
are expected to diminish after sunset.
No major changes were noted with the new 12Z guidance for Sunday and
Monday. Best chance of showers for Sunday remain across the eastern
sections of Santa Cruz County and most of Cochise County.
A stronger shortwave will pass through the area Monday, bringing
continued cool temperatures and a renewed threat for isolated
showers across Graham and Greenlee Counties. Elsewhere will remain
dry. The dry weather will continue into Tuesday and at least the
daytime on Wednesday.
The biggest changes in the extended range were to increase POPs
modestly from late Wednesday into Friday morning as a much stronger
storm system moves across the region. Forecast guidance continues to
suggest a wet system, with a good soaking rain and high elevation
mountain snow.
Beyond Friday morning, greater uncertainty remains with the
forecast. There could be another storm system moving across the
region, however the details will need to be ironed out as we
progress into next week.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
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