Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 12/16/19
Area Forecast Discussion
National Weather Service Grand Rapids MI
918 PM EST Sun Dec 15 2019
LATEST UPDATE...
Update
.SYNOPSIS...
Issued at 235 PM EST Sun Dec 15 2019
- Storm system passes by to the south on Monday
- Lake effect snow showers late Tuesday into early Wednesday
- Cold for mid week
- Not as cold next weekend
&&
.UPDATE...
Issued at 918 PM EST Sun Dec 15 2019
The inherited forecast is on track with no changes needed.
More technical discussion:
A large band of wintry precipitation extends from West Virginia
into west central Illinois associated with a baggy surface low
pressure trough across the southern US. A separately-forced area
of light radar returns extends from central Wisconsin to eastern
Iowa, which is associated with a subtle and weak shortwave trough
embedded in otherwise zonal mid-level flow. Surface observations
indicate nothing is making it to the ground roughly north of I-80
and indeed with the latter feature, with the 00Z DTX RAOB as well
as recent AMDAR aircraft soundings from the Milwaukee and Chicago
areas showing an incriminating pocket of very dry air centered at
about 3000 ft. So, most of the radar returns upstream of our area
are indicative of virga. As a broad trough continues digging into
the Four Corners region through the overnight hours, the
aforementioned shortwave responsible for virga upstream will
dampen considerably leading to weakening support for continued
mid-level precipitation development. Coupled with the pocket of
dry air at 3000 ft, it seems unlikely anything more than a flurry
or two will be able to make it down across western Lower Michigan
overnight. As such, we favor a continued dry forecast.
With continued cloud cover and nearly no wind in the lowest few
thousand feet of the atmosphere (e.g. little in the way of any
sort of advection), temperatures overnight will remain steady
through daybreak.
&&
.DISCUSSION...(This evening through next Sunday)
Issued at 235 PM EST Sun Dec 15 2019
The main challenges in the period deal with timing and amount of
any impacts. To start there is an area of light snow in eastern
Nebraska and western Iowa. This area of snow was tracking
east...in our direction. Models show the lift weakening with this
feature as it moves into Southern Lower Michigan late tonight into
Monday morning. This will support a diminishing trend the light
snow through the night into Monday morning. Still a small risk for
a period of flurries or perhaps light snow exists for Southern
Lower Michigan. Bufkit overviews do show a dry layer from 2000 to
roughly 5000 ft. This likely is not enough to prevent some of the
snow from reaching the ground. We will feature low POPs for
measurable precipitation after midnight tonight for the
Interstate 94 corridor.
Next up will be the lake effect snow later Tuesday into Wednesday.
Deeper cyclonic flow and the arrival of an arctic airmass will
support some impacts for parts of the region. Right now the models
are showing the best lift arriving Tuesday evening after 00z as a
700 mb wave drops in from the northwest. This is when we will
feature the highest POPs. With a Lake Superior connection...the
bands in northwest parts of our CWA will likely produce the most
impacts...which could linger into Wednesday morning. Guidance
shows a low level ridge building in for Wednesday afternoon and
evening which should support decreasing and less organized snow
shower activity. It is worth noting that the DGZ lowers close to
the ground...under the cloud bases late Tuesday night into
Wednesday which would likely alter the accumulation rate.
Deeper southwest flow develops for late in the week and through
the weekend which will support a moderating trend to the
temperatures.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 620 PM EST Sun Dec 15 2019
Broken MVFR clouds continue at many TAF sites as of this writing
partly due to a lack of any real advection in the lowest few
thousand feet. As such, opted to maintain MVFR clouds at many of
the TAF sites through much of the TAF period with occasional
breaks to VFR (OVC100 or above). Virga is expected at all TAF
sites from midnight through about 18Z today though a few flurries
can`t be ruled out at AZO/BTL/JXN. Winds will remain light and
variable through the entire TAF period.
&&
.MARINE...
Issued at 235 PM EST Sun Dec 15 2019
With surface high pressure forecasted to ridge into the region
tonight into Monday...the winds and waves are forecasted to remain
relatively low. That will change for Tuesday. The wind is
forecasted to strengthen out of the northwest as an arctic
airmass spreads in through Wednesday. Thus...hazardous small craft
conditions are likely to redevelop. Freezing spray may be possible
as well. High pressure ridges in for later Wednesday into
Thursday. At this time it looks like conditions will improve
somewhat then.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&
$$
UPDATE...Borchardt
SYNOPSIS...MJS
DISCUSSION...MJS
AVIATION...Borchardt
MARINE...MJS
Area Forecast Discussion
National Weather Service Pueblo CO
639 PM MST Sun Dec 15 2019
.UPDATE...
Issued at 639 PM MST Sun Dec 15 2019
With the slower movement of the passing trough and latest higher
res models keeping snow ongoing across the eastern mountains and
immediate adjacent plains through the morning hours, have extended
winter storm warnings and advisories for these areas through 16z
(9 AM MST). Also updated snow totals, with additional snow accumulations
of 4 to 10 inches along and west of the I-25 Corridor, greatest over
and along the lower eastern slopes, especially south and west of
Pueblo. Snow fall of 1 to 4 inches will remain possible across the
rest of south central and southeast Colorado into early Monday
morning.
&&
.SHORT TERM...(This evening through Monday)
Issued at 253 PM MST Sun Dec 15 2019
...Snow will pick up in Colorado Springs and Pueblo around 6 pm this
evening...
Currently...
Storm has been an over-achiever in several areas as Walsenburg is up
to a foot, and parts of the San Luis Valley (SLV) floor have
received 4-6", and Leadville proper is over 2 feet of snow in the
last ~60 hours.
At 2 pm this afternoon. radar was showing snow up and down the I-25
corridor from roughly south of COS down to KTAD. Heaviest snow was
down on the Raton Mesa. Looking at CDOT web cams, roads everywhere
were just wet except at the passes where they were snow packed.
Temps across the region were just below freezing along the I-25
corridor with mid 30s across the rest of the eastern plains, except
vicinity KSPD were temps were in the low 30s. The SLV was in the
upper 20s to around 30F. Mtn tops were in the single digits, so
lower level lapse rates were pretty steep over the region.
Rest of Today and Tonight...
All of the guidance have been very insistent at indicating snow
across the I-25 corridor will start to pick up in earnest generally
after 6 pm and should last until 5-6 AM tomorrow morning. 0.15 to
0.25 liquid is expected to fall in the COS area with higher amounts
west of town, and KPUB should get around 0.40 liquid. As we have
been advertising on social media, there is going to be a very tight
gradient in snowfall depth in the PUB and COS areas, with areas
generally east of the interstate not receiving much snow while areas
just to the west receiving over 6". Down towards Walsenburg and
Trinidad, the snow will push farther out onto the plains (as
Walsenburg has already received a foot of snow, as mentioned above).
The Wets, wet mtn valley and the eastern slopes of the Sangres are
likely going to do quite well with this storm, as snowfall totals
will likely be in the 1-2 feet range. The SLV should get a few more
inches before it ends later tonight.
Temps tonight should fall into the tens across the plains with
single digits and negative single digits across the SLV and mtns.
Tomorrow...
Some light snow will be ongoing across the plains and s mtns
tomorrow morning, but should come to an end by late morning. with
fresh snowfall, areas around the Raton Mesa should remain below
freezing tomorrow while out east should see temps in teh mid 30s.
SLV should be cold all day with temps in the U20s. MTNS will remain
quite cold with single digits for highs.
.LONG TERM...(Monday night through Sunday)
Issued at 253 PM MST Sun Dec 15 2019
Monday night...The upper level low pressure trough will be exiting
the region, as a ridge of high pressure moves into the western US.
Save for a few lingering snow showers across the sw and s mts during
the early evening, skies will be clearing through the night with a
very cold night anticipated. Overnight minimum temps are forecast to
be below zero for the mts and high valleys, and single digits for
the plains.
Tuesday and Wednesday...Temporary ridging pushes into the Four
Corners region, with dry and slowly warming conditions expected.
Plan on highs on Tue to be a bit cool, with teens and 20s for the
high valleys, and 30s to near 40F for the plains. Wed should be
about 7-10 degrees warmer.
Thursday...Long range models indicate another fast-moving upper low
crossing the area on Thu. At this time it looks like it will be dry
and will mainly increase cloud cover across the forecast area,
though a snow shower or two over mt areas is not out of the
question. Highs will remain nearly the same as wed, with readings in
the mid 20s to mid 30s for the high valleys, and 40s to near 50F for
the plains.
Friday through Sunday...Another upper ridge of high pressure will
slide across the region, providing for a dry and gradually warming
weekend. Look for highs in the 30s for the high valleys and 40s to
around 50F for the plains on Fri. Sat and Sun will be warmer with
highs in the mid 30s to mid 40s for the high valleys, and 50s to
lower 60s for the plains. Moore
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 253 PM MST Sun Dec 15 2019
MVFR and LIFR conditions are likely, especially after dark at each
of the 3 TAF sites, KALS, KCOS and KPUB. Conditions will start to
clear by mid morning tomorrow as the weather system moves off to the
east. Winds will be light, but the snow will likely accumulate on
aircraft surfaces/runways due to the falling temperatures.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until 11 AM MST Monday for COZ088.
Winter Storm Warning until 9 AM MST Monday for COZ072>083-086-
087.
Winter Weather Advisory until 2 AM MST Monday for COZ062-063-065-
067-069>071.
Winter Weather Advisory until 11 AM MST Monday for COZ094.
Winter Storm Warning until 2 AM MST Monday for COZ066-068.
Winter Weather Advisory until midnight MST tonight for COZ064.
Winter Weather Advisory until 9 AM MST Monday for COZ084-085.
&&
$$
UPDATE...MW
SHORT TERM...HODANISH
LONG TERM...MOORE
AVIATION...HODANISH