Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/30/21
Area Forecast Discussion
National Weather Service Bismarck ND
938 PM CST Wed Dec 29 2021
.UPDATE...
Issued at 938 PM CST Wed Dec 29 2021
At 03Z, the GOES-East Nighttime RGB channel showed a persistent
area of lower level clouds from the southwest and south central
through the James River Valley. With 1700-5000ft ceilings, this
stratus has kept temperatures over these areas relatively warmer
and consistent over the past several hours. RAP guidance continues
to show 925-850mb RH fields indicative of expanding cloud cover as
a shortwave approaches tonight, which could warm temperatures that
had previously bottomed out this evening. No changes will be made
to the ongoing Wind Chill Advisory over the south at this time, as
breaks in the clouds can allow for temperatures to rapidly cool
off, but areas under continued stratus overnight may not reach
advisory criteria.
Over the northern tiers of counties, skies are clear and wind
chills are currently near or colder than 40 below zero across the
Wind Chill Warning area. As previously stated, a northward
expanding cloud deck may somewhat warm some of these temperatures
tonight, but the northward extent of stratus expansion is
uncertain.
Light snow remains possible after midnight over the central and
east and precipitation chances were expanded based on 00Z high-
resolution trends. Just light accumulations of a few tenths down
to a trace are expected.
UPDATE Issued at 556 PM CST Wed Dec 29 2021
At 00Z, wind chills range from 20 below to 30 below across the
south and 30 below to near 45 below across the north. Bitterly
cold temperatures will remain, and wind chill headlines are in
good standing. Light snow reports have mostly diminished this
evening, though should return as the next previously discussed
wave arrives. No changes needed with this update.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 235 PM CST Wed Dec 29 2021
Continued frigid temperatures and dangerous wind chills will
highlight the short term period, along with a little light snow
today and tonight for some areas.
Currently, active pattern continues as another embedded wave
continues to swing through the region this afternoon, pushing
light snow or flurries across the southwest, central, and east.
Afternoon temperatures frigid, ranging from the teens below north
to near zero south.
For tonight, despite cold high pressure across the region,
another embedded wave will push east across the state and bring a
little more light snow to some areas, maybe a tenth or so before
ending late. Main story again will be the bitter cold. Will go
with a wind chill warning across my north, along and north of
Highway 2, and a wind chill advisory south. Will let both products
run through early Thursday afternoon.
A moderation in temperature finally for Thursday as some return
flow develops across the region. Still below normal, but an
improvement nonetheless.
.LONG TERM...(Thursday night through Wednesday)
Issued at 235 PM CST Wed Dec 29 2021
The main highlight in the long term period remains the continuous
dangerously cold weather, at least into New Year`s Day. Actual
temperatures near 30 below and wind chills near 50 below from time
to time through that period still look to occur, especially
northern areas of North Dakota. NBM and most ensemble guidance
agree with the continued cold, bottoming out late this week and
into Saturday. A continuation of wind chill headlines can be
expected during this period.
All guidance suggests a reprieve from the frigid cold, at least
for a day or two, beginning Sunday. An upper level ridge will
build across the region late this weekend and into early next
week, with a west wind scouring out the cold air, at least across
the west and central. Eastern areas may not be as lucky, but
should still see a moderation in temperatures to some degree.
Afterwards, the consensus is for a gradual cooling trend,
bottoming out late next week.
Overall, not much as far as precipitation through much of the
extended. There is increasing agreement amongst the ensembles and
blends with better chances for precipitation developing Tuesday
and onwards. This is when more of an active mid level flow pattern
develops to the east across the northern tier of the country.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 556 PM CST Wed Dec 29 2021
VFR for most areas of western and central North Dakota to start
the evening, with areas of MVFR cigs south of KDIK-KBIS-KJMS. Then
an area of MVFR/IFR clouds expected to develop after 09Z or so
with perhaps some light snow. Conditions expected to improve after
12Z-15Z Thursday, though MVFR may linger through the day north.
KXWA may remain VFR through much of the period, more likely
becoming MVFR after 20Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
Wind Chill Advisory until 2 PM CST /1 PM MST/ Thursday for
NDZ017>023-025-031>037-040>048-050-051.
Wind Chill Warning until 2 PM CST Thursday for NDZ001>005-
009>013.
&&
$$
UPDATE...AE
SHORT TERM...NH
LONG TERM...NH
AVIATION...AE
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
822 PM EST Wed Dec 29 2021
.UPDATE...
The afternoon forecast package nudged the chances for light snow up
a tad across the Saginaw Valley and thumb region. Upstream returns
across nrn Illinois and latest HRRR runs are suggestive of a little
more activity high up the frontal slope, which will impact the
northern portions of the forecast area overnight. For this reason,
pops will be nudged upward a little more across the Saginaw Valley
and thumb region.
Despite the abundance of returns upstream, weakening large scale
ascent and an increasing low level dry layer over Se Mi overnight
will still limit the extent of light snow. So low chance type pops
for light snow with minimal accumulations still looks reasonable.
&&
.PREV DISCUSSION...
Issued at 559 PM EST Wed Dec 29 2021
AVIATION...
The passage of a weak cold front is driving drier low level air into
Se Mi. The result has been a gradual erosion of the low stratus from
west to east. This trend will persist through the start of the TAF
period. The region of precipitation extending from the Lower Ohio
Valley into Iowa is associated with a mid level short wave and upper
frontal dynamics. This system will lift across Se Mi overnight, but
will weaken considerably. This and the ongoing push of low level dry
air into Se Mi will warrant just a TEMPO for some light
snow/flurries in the terminals in the 08Z to 11Z time frame. The
development of light south winds on Thursday will slowly drive the
MVFR stratus deck back northward into Se Mi during the course of the
day.
For DTW...Recent hi res model guidance suggests the best potential
for light snow/flurries at metro will be in that 08 to 11Z time
window. Little or no accumulation is expected.
DTW THRESHOLD PROBABILITIES...
* Low in ceilings below 5000 ft overnight. High on Thursday.
* High for snow precipitation type late tonight and Thursday
morning.
PREV DISCUSSION...
Issued at 346 PM EST Wed Dec 29 2021
DISCUSSION...
Subtle midlevel ridging and subsidence in the wake of the departing
weak surface trough has lowered the low-level inversion this
afternoon while light westerly wind has helped entrain drier air
into the near-surface layer. This has worked to scour out the
persistent early day fog and may even help scatter some of the
stratus over the next few hours. Mild temperatures late this
afternoon and early this evening drop into the mid to upper 20s
tonight /lower 30s for Metro Detroit/.
Trends in the latest model runs have significantly lowered the
already limited chance for light snow overnight and early Thursday
morning for areas south of the I-69 corridor. This potential is
driven by the arrival of a low-amplitude shortwave tracking through
the west-southwest mean flow along the resident baroclinic zone over
the southern Great Lakes. Soundings depict a dry layer around 900-
950mb that forcing will have a hard time overcoming as much of the
ascent is spent saturating the mid levels. Will lower PoPs but
maintain a slight chance/chance of light snow south of I-69 tonight.
Accumulations are not likely in this area, though a dusting can`t be
ruled out by Thursday morning.
Of note in much of the hi-res suite is coherent signal for a band of
light snow to track into the Saginaw Valley around midnight as well.
This band is visible this afternoon in regional radar mosaic over
Iowa. Models show this riding in on the main height fall corridor
associated with the PV anomaly with cross sections showing favorable
omega and lower static stability near the DGZ around 600-700mb. As
discussed above, the limiting factor will be dry air below this
layer that will need to be overcome. Stronger forcing looks to occur
for such a brief window that confidence is low on this occurring and
for minor snow accumulation to occur. While PoPs in the south have
been lowered, will raise PoPs across the Saginaw Valley and Thumb to
show a chance for this band of snow to work in.
Benign but mostly cloudy weather follows for Thursday into Friday
with zonal flow aloft and a diffuse pressure pattern at the surface.
May see occasional fog and/or low-impact drizzle both days as
soundings advertise a sufficient amount of moisture in the lower
levels. Temps take a step downward Thursday with highs in the mid to
upper 30s, but a weak warm front moving through Thursday night helps
bump Friday temps well into the 40s across most of Southeast
Michigan.
Attention remains focused on this weekend for a period of more
impactful weather across the Great Lakes. A broad northern stream
Pacific trough dislodges from the western CONUS while consolidating
with a stronger southern stream low from the northern Baja region on
Friday. Cold air sinking south with the northern stream wave
tightens the temperature gradient across the country which the
phased/amplifying trough then capitalizes on to develop a strong low
pressure system that tracks from the central/southern Plains into
the upper Ohio Valley by Sunday. Much of the variance among the
ensemble space can be explained by the translation speed of the
system as it works northeast along the baroclinic zone. This speed
will be ultimately driven by the pace that a Pacific ridge is forced
into and across the western CONUS later this week. However,
confidence is rather high at this point for Southeast Michigan to be
positioned northwest of the low track and to see a period of
accumulating/impactful snowfall late Saturday into Saturday night.
Too soon to pin down amounts, but holiday travel disruptions will be
possible late Saturday and Sunday. This is followed by a surge of
much colder air with highs in the 20s and lows in the teens to start
the first week of the new year.
MARINE...
Southwest winds this afternoon veer to the north tonight as weak low
pressure and its attendant frontal boundary track east of the Great
Lakes region. Winds remain light even in the wake of the frontal
passage, with peak gusts to around 25 kts in northern Lake Huron and
lower gust potential further south. Aside from light rain and snow
showers overnight, conditions remain dry through the end of the work
week. Attention then turns to the holiday weekend, in which a high
impact weather system brings increased winds/waves and widespread
precipitation chances to the region.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&
$$
UPDATE.......SC
AVIATION.....SC
DISCUSSION...TF
MARINE.......MV
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Grand Rapids MI
1034 PM EST Wed Dec 29 2021
LATEST UPDATE...
Update
.UPDATE...
Issued at 1034 PM EST Wed Dec 29 2021
Our snow event tonight is looking a little more ambitious than
early today. As I stated below these sort of events like to
overperform. Several runs of the HRRR have consistently showed
around a half inch, maybe even in inch in a narrow band from
Muskegon County, across northern and central Kent County into
Montcalm and southern Newaygo Counties just after midnight. Given
we now have many sites on N IL, E IA, and southern WI all
resorting snow reaching the ground and our radar is showing F-GEN
like snow bands heading this way, it made sense to me to believe
it will snow were the HRRR is now forecasting it. So, I increased
the pop to likely slightly increased the snowfall forecast in that
narrow band. Most areas will only get a TRACE from this event.
UPDATE Issued at 659 PM EST Wed Dec 29 2021
I made changed the snow showers to light snow in the grids since
this is a stratiform precipitation event tonight and that matches
the other offices that have light snow as verse snow showers
overnight. I slightly increased the pop overnight to between 40%
and 50% near and south of I-96. This is one of those warm
advection events and those seem to just about always overperform
for us. There is 35 to 40 knots perpendicular to the 295k
isentropic surface (near 700mb) in the midnight to 3 am time
frame. Condensation pressure deficits fall to near 10 mb so it
will snow from that layer as there is decent lift at that time.
The only question is, can it reach the ground? There is about 6000
ft of dry air to overcome for the snow to reach the ground. Just
about all of this activity will be near and south of I-96 around
midnight. The shortwave causing this is east of the area by 3-4
am. Given the short window for this snow event and that it will
struggle to reach the ground, it`s hard to imagine we`d get more
than a quarter inch of this event. So impacts should be rather
limited.
&&
.DISCUSSION...(This evening through next Wednesday)
Issued at 330 PM EST Wed Dec 29 2021
- Light Snow Tonight
The southern stream remains active with a plume of Gulf moisture
streaming across the Tenn/Ohio valleys and a weak baroclinic wave
bringing an area of mid level f-gen across southern Lower Michigan
tonight. The transport of deep moisture is weaker than the event
yesterday, as shown in model soundings that maintain a dry wedge
in lower levels through the event, so we expect amounts to be
limited to a dusting to an inch with the highest amounts across
the southern forecast area. Little to no impacts expected for
travel.
- New Years Day Winter Storm
Travel impacts are expected over the weekend, especially from
Saturday afternoon into Sunday morning, as a winter storm with
several inches of snow is becoming more likely. The ECMWF has been
fairly consistent the past couple days in showing a stripe of
heavy snow across our forecast area and the GFS trended that way
yesterday and continues today, so confidence is increasing. The
trend has also been for a colder storm, with even our southeast
forecast area getting all or mostly all snow. The 12Z GFS model
sounding at AZO and JXN show all snow by the time the steadier
precip arrives during the late morning on Saturday.
The synoptic set up is interesting in that we are poised to get
heavy snow without a deepening or even well-defined surface low.
Indeed, the surface low does not begin to intensify until it is
well past our longitude and the upper trough goes negative tilt.
The main driver here is strong mid-level frontogenetic forcing
which results from strongly confluent flow ahead of the advancing
positively-tilted longwave trough. The confluence strengthens the
baroclinic zone between SE CONUS ridging and the upper trough.
Deep Gulf moisture is also available in this flow regime.
A 1028mb surface high of arctic origin is centered over the
Northern Plains with sfc ridging extending eastward across
southern Canada feeding cold air at the surface on northeast low
level winds, which will increase snow ratios to 10 to 1 or higher
during this event, unlike the "warm snows" we have seen so far. At
this point it looks like 4 to 8 inches across much of southern
Lower Michigan but mesoscale banding that persists/pivots over
the same could result in locally higher amounts.
Some lake effect snow showers are expected on Sunday but
inversion heights below 5000 kft should prevent heavy
accumulations. Snow is possible again by Wednesday as a clipper
tracks across the northern Plains towards Lower Michigan.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 659 PM EST Wed Dec 29 2021
We have just had a cold front occlusion come through the area.
This is bringing with it low level dry air and that is clearing
out all of the MVFR cigs early this evening. So, by 03z all TAF
sites should have light and variable winds and cloud bases that
are VFR, many will be above 10000 ft for a few hours anyway.
A period of light snow is seen in the 06Z to 09Z time frame. We
may see MVFR visibilities as this moves through are some of our
TAF sites. GRR and LAN have the greatest risk of that happening.
This is the result of quick moving shortwave will track through
the area. The glitch is there is forecast to be a 6000 ft dry
layer below the base of the clouds creating the snow. It`s
questionable that the snow can reach the ground. If it does there
may well be a period of MVFR or even IFR visibility`s for a short
time.
Once that is done VFR should prevail till mid to late morning. At
that point another wave on the front to our south will send more
low level moisture back our way. That will mean MVR cigs at all
TAF sties but IFR in the southern TAF sites by mid to later
afternoon. Winds will remain light and variable through Thursday.
&&
.MARINE...
Issued at 330 PM EST Wed Dec 29 2021
After a short lived burst of higher winds and waves this
afternoon, we expect conditions will be relatively tranquil until
the weekend when they increase in strong cold advection on the
backside of the snow storm on New Years Day.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&
$$
UPDATE...WDM
DISCUSSION...Ostuno
AVIATION...WDM
MARINE...Ostuno
Area Forecast Discussion
National Weather Service Houston/Galveston TX
951 PM CST Wed Dec 29 2021
.UPDATE...
Visibility is decreasing across Southeast Texas as fog begins to
crop up. In the area most expected to see fog impacts, sites like
Angleton, Bay City, and Palacios have already fallen below half a
mile at times. A dense fog advisory will likely be needed tonight
for a portion of the area, and how large an area is needed will
be a focus of determination late this evening. Much of the area is
still in the 3-7 mile range, and there is still uncertainty in how
much more of the area will actually see widespread dense fog.
One complicating factor for now is that some cirrus is making its
way overhead, and is hampering the environment just enough to make
visibility pretty variable. I`m hoping that we can see enough
disruption in dense fog that any advisory can remain small or even
not necessary. Regardless, anyone out and about tonight and early
tomorrow morning will want to be alert for visibility to change
across short amounts of time and/or distance, including patches of
dense fog.
&&
.AVIATION [03Z TAF Update]...
Visibility at typically foggy sites CXO and LBX are degrading more
quickly than anticipated. Amendments have already been made, and
more amendments are likely as the night goes on. Will continue to
try to stay on top of the observational trends without
overcorrecting to being too pessimistic - there is some cirrus
overhead that is helping keep visibility up at several locations
for now, and could cause some variability through the night.
&&
.PREV DISCUSSION /Issued 553 PM CST Wed Dec 29 2021/...
.SHORT TERM [Through Thursday Night]...
A dry line over Central Texas will push eastward tonight but it`s
still unclear on whether this feature will make it into the CWA and
if it does, where it will stall. Have leaned toward a model
consensus which brings the boundary into our western zones and then
stall it out there but the latest HRRR and the NAM keep it west of
the region through 10z. Why is it important? Drier air to the west
of the boundary will keep skies clear and allow sfc dew points to
fall into the 50`s allowing for cooler MinT values. Ahead of the dry
line, it will stay warm and humid with MinT values staying in the
upper 60`s to around 70 degrees. With lighter winds and some partial
clearing this evening, conditions look quite favorable for fog, some
locally dense. SREF probabilities show a high likelihood for dense
fog tonight for areas S-SW of Houston. Sea fog looks possible near
the coast as well as lower 70 dew points override cooler shelf
waters in the 60`s.
As for Thursday, morning fog will dissipate between 16-17z and
ceilings will begin to mix out by early afternoon. A relatively warm
start to the day coupled with warm 850 mb temperatures will allow
MaxT values to warm into the lower 80s yet again. Slightly cooler
both out west (due to cooler morning temps) and along the coast as
patchy fog could limit heating into the afternoon. Could again get
some patchy fog Thursday night into Friday morning, especially over
the western CWA. Dew points creep back up into the upper 60`s so
MinT values should remain very warm with lows mainly in the upper
60`s. 43
.LONG TERM [Friday Through Wednesday]...
Where are you winter?
Why can`t I find you?
Why have you gone away?
Where is the cold air...
You used to bring me.
Send a cold front our way!
Unfortunately, don`t expect winter to really feel like winter for
the rest of the year. With the last gasp of a prevailing upper-level
ridge, temperatures on New Year`s Eve (Friday) will top out in the
low to mid 80s. Southwesterly winds aloft will border 19-20 degrees
Celsius and with a LLJ developing in our western counties ahead of
an approaching cold front and steep LL lapse rates, we`ll see
sufficient mixing supportive of these above normal temperatures. The
LLJ strengthens overnight to 45-50 knots, so we could be in for a
breezy night depending on how much PBL decoupling occurs.
Speaking of cold fronts, what better way to kick off 2022 than with
a strong FROPA! New year, new me...I mean new temperatures. A deep
upper-level trough digging down from the western CONUS will push in
a strong cold front on New Year`s Day (Saturday). The front will
push through the Brazos Valley in the mid-to-late morning and reach
the coast by the afternoon. This makes the high temperature forecast
for Saturday a bit tricky, since there is a substantial temperature
gradient behind the front. This will be a day where the high
temperature will occur one minute prior to FROPA and fall through
the remainder of the day. Pre-frontal heating though will lead to
one more day in the 80s for those along and south of I-10, with 70s
northward. Models have continued to trend towards a dry FROPA for
locations west of I-45, so PoPs remain higher east of I-45. Thus our
northeastern counties (Houston/Trinity/Polk) have the best chance of
showers/thunderstorms along the frontal boundary. Model soundings
show quite a bit of shear, so an isolated strong storm cannot be
ruled out. Expect breezy northerly winds in the wake of the front,
especially closer to the coast. For those with Christmas decorations
still up, make sure they are properly secured...I don`t think Santa
wants to take flight again!
Now let`s talk temperatures. If you`ve been holding out hope for a
chance to break out your winter jacket or try out that new soup
recipe you found, this will be the time to do so. Temperatures on
Saturday night will dip into the upper 20s/low 30s north of I-10,
but with the wind factored in it will feel like the 10s and 20s. If
you miss out on hitting the freezing mark on Saturday night, you`ll
likely reach it on Sunday night with 32 degrees or below in the
grids for nearly all of Southeast Texas (except along the coast).
Freeze Warnings will likely be needed this weekend. Northeastern
locations may reach Hard Freeze territory on Sunday night with lows
in the mid 20s. Remember the four P`s this weekend: protect people,
pets, plants, and (external) pipes to keep them safe from the frigid
temperatures. High temperatures for Sunday will range from the mid
40s to the low 50s, which is a good 35+ degrees colder than we`ve
seen over much of the abnormally warm December. Surface high
pressure scoots out to the east by Tuesday leading to the return of
onshore flow and a warmup going into midweek. However, models agree
on zonal flow aloft, so temperatures "shouldn`t" climb to be as
abnormally warm as we saw in parts of December. The higher end of
NBM guidance is still below 80 degrees for Southeast Texas on
Wednesday, so we`ll take that as a small victory!
Batiste
.MARINE...
Offshore seas remain elevated at 6 feet, so small craft should
continue to exercise caution through the evening hours as seas
subside. Light to occasionally moderate onshore flow will continue
through tonight before winds become light and variable. This will
lead to the potential for fog tonight/early Thursday morning for the
bays and nearshore waters. On Friday, onshore flow strengthens to at
least caution levels in the morning and likely to advisory levels by
night ahead of an incoming cold front that will push offshore by
Saturday afternoon. Cold air flowing over the warm waters will lead
to an enhancement of the offshore flow that follows in the wake of
this front, so expecting sustained winds near gale force with gusts
over 40 knots through Sunday morning. Offshore seas are expected to
rise to 9-10 feet by Sunday as a result. A Gale Warning can be
expected for Saturday evening through Sunday morning. Offshore flow
doesn`t last too long as surface high pressure pushes east of SE
Texas by Tuesday and onshore flow returns. Saturday`s cold front
will cause a decrease in coastal water temperatures, and with
dewpoints increasing sharply into the 60s by early Wednesday
morning, we could be in store for a round of sea fog.
Batiste
.CLIMATE...
Today, we broke record high temperatures at Galveston, the City
of Houston, Houston-Hobby, and College Station. Record high max
and min temperatures were set yesterday for the City of Houston,
Houston-Hobby, and the City of Galveston. The most impressive one
being the record high max temperature of 82 at Galveston
yesterday which crushed the old record by six degrees, is the
warmest temperature on record for any day of December, and is now
the latest 80 degree day for the calendar year on record. This was
the sixth day this month that the temperatures at Galveston
climbed into the 80s, which is more than all the previous times
Galveston has climbed into the 80s in December on record combined
(four times:
81 on 12/16/2016, and 80 on 12/1/2018, 12/20/2007, and
12/10/1918).
This month will be the warmest December on record for Houston,
Houston-Hobby, and Galveston and will be close for College Station:
Current Average TempPrevious Warmest December
College Station:65.866.6 (1889)
Houston:67.164.4 (1933)
Houston-Hobby:69.064.8 (1984)
Galveston:69.366.4 (1889)
And you can expect these average temperatures to increase by the
end of the month. To put it in perspective, we are experiencing near
normal April temperatures, but in December.
In comparison to the cold outbreak this past February:
February Departure from NormalDecember (so far)
College Station:-6.4+12.6
Houston:-4.7+11.5
Houston-Hobby:-5.1+12.0
Galveston:-3.7+10.5
So, relative to our coldest month compared to normal this year, this
December will be near double the difference compared to normal, but
in the opposite direction.
Daily record highs and high minimum temperatures will be possible
through Friday.
Here are the upcoming record highs/dates:
College Station area...
- Wed (29th): 80/1984
- Thu (30th): 81/1951
- Fri (31st): 82/1951
- Sat ( 1st): 81/2006
Houston area...
- Wed (29th): 81/1984
- Thu (30th): 83/1974
- Fri (31st): 82/1974
- Sat ( 1st): 81/2006
Houston Hobby...
- Wed (29th): 81/1984
- Thu (30th): 83/1974
- Fri (31st): 81/1951
- Sat ( 1st): 82/2006
Galveston area...
- Wed (29th): 75/1889
- Thu (30th): 75/2020
- Fri (31st): 74/1921
- Sat ( 1st): 76/1934
Fowler
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 57 80 65 82 67 / 0 0 10 20 20
Houston (IAH) 64 81 68 83 71 / 10 0 10 20 10
Galveston (GLS) 67 75 68 79 72 / 0 0 10 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 6 AM CST Thursday for
the following zones: Waters from Freeport to Matagorda Ship
Channel TX from 20 to 60 NM...Waters from High Island to
Freeport TX from 20 to 60 NM.
&&
$$
UPDATE...Luchs
SHORT TERM...43
LONG TERM...Batiste
AVIATION...Luchs
MARINE...Batiste
CLIMATE...Fowler
Area Forecast Discussion
National Weather Service Memphis TN
956 PM CST Wed Dec 29 2021
.UPDATE...
Thunderstorms pushed out of the area a couple of hours ago. A
stalled front remains draped across Northwest Mississippi and
into West Tennessee near the Tennessee River. The HRRR shows dense
fog developing along and north of the front. Went ahead and issued
a Dense Fog Advisory for much of the CWA. Made some adjustments to
temps and lower POPS for the overnight hours.
KRM
&&
.DISCUSSION.../issued 306 PM CST Wed Dec 29 2021/
Skies remain cloudy over a large portion of the Mid-South this
afternoon. The frontal boundary currently extends from northern
sections of middle Tennessee and continues into northwest
Mississippi. Temperatures continue to vary quite a bit depending
on what side of the boundary with readings in the lower 50s to mid
70s. Showers and thunderstorms are mainly along the frontal
boundary with some additional showers behind it. A tornado watch
remains in effect for roughly the southern half of the Mid-South
until 7 PM CST.
The front will continue to move southeast tonight with the rain
ending from northwest to southeast. Temperatures will remain above
normal tonight with lows Thursday morning from the mid 40s to
lower 60s. On Thursday, the boundary will lift back north bringing
another day of dry and warm weather to the region. Temperatures
will remain well above normal on Thursday with highs from the
lower 60s to mid 70s.
By late Thursday night, some additional showers are possible ahead
of the next weather event. By Friday, a large upper level low will
start to move out of the southern Rockies and into the Plains.
Showers and thunderstorms will become more numerous by the
afternoon hours. Temperatures will remain quite warm on Friday
with highs in the upper 60s to mid 70s.
By Friday night, a cold front will move toward the region.
Numerous showers and thunderstorms will develop ahead of the
front. Severe weather is possible Friday night with heavy rainfall
also a threat. The cold front will move through on Saturday with
more thunderstorms that could produce severe weather as well as
heavy rainfall.
High pressure will start to build into the region by late Saturday
night with rain ending from north to south. Much colder air will
move into the Mid-South by late Saturday night with lows in the
20s Sunday morning.
High pressure will influence the weather for the remainder of the
forecast period with dry weather expected from Sunday through next
Wednesday. Temperatures will be some 15 degrees below normal on
Sunday before returning to near normal on Tuesday and then getting
above normal next Wednesday.
ARS
&&
.AVIATION...
00Z TAFs
IFR expected to expand in the cool, moist bubble high pressure
system left in the wake of thunderstorms. Greatest IFR/LIFR
potential is expected over northeast AR after 03Z, near the
position of the surface high. HRRR appears on track in expanding
the IFR/LIFR southeast through the overnight. Improvement will
occur mid/late morning Thursday, southwesterly winds and driving
the diffuse warm front north.
PWB
&&
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...Dense Fog Advisory until 9 AM CST Thursday for Clay-Craighead-
Crittenden-Cross-Greene-Lee AR-Mississippi-Phillips-
Poinsett-St. Francis.
MO...Dense Fog Advisory until 9 AM CST Thursday for Dunklin-Pemiscot.
MS...Dense Fog Advisory until 9 AM CST Thursday for Alcorn-Benton MS-
Coahoma-DeSoto-Lafayette-Marshall-Panola-Quitman-
Tallahatchie-Tate-Tippah-Tunica-Yalobusha.
TN...Dense Fog Advisory until 9 AM CST Thursday for Benton TN-Carroll-
Chester-Crockett-Decatur-Dyer-Fayette-Gibson-Hardeman-
Hardin-Haywood-Henderson-Henry-Lake-Lauderdale-Madison-
McNairy-Obion-Shelby-Tipton-Weakley.
&&
$$
Area Forecast Discussion
National Weather Service Nashville TN
844 PM CST Wed Dec 29 2021
.UPDATE...
FOR EVENING DISCUSSION.
&&
.DISCUSSION...
Used a HREF, RAP_13, HRRR blend per best initialization and
realistic weather pattern evolution through remainder of
tonight across mid state region. Heaviest rainfall has just
about moved east of Cumberland Plateau Region. Tweaked hourly
temperature, dewpoint, wind speed/direction and sky condition
grids blending them with associated late evening gridded values.
Current temperature trends generally in line with forecasted lows.
In agreement with surrounding offices, added patchy fog after
midnight through mid morning hours on Thursday. Remainder of
forecast continues to be on track.
&&
.AVIATION...
00Z TAF DISCUSSION.
CKV/BNA/MQY/CSV...Several admendments possible at least thru
30/06Z due to convection moving across region. Strongest storms
continue to remain well south of terminals. MVFR vsbys and VFR
ceilings prevailing at terminals presently, but some fluctuations
expected. Brunt of convective activity should be E of terminals
by 30/04Z. MVFR ceilings/vsbys should prevail after convection
moves E with IFR ceilings/vsbys possibly 30/10Z W-30/20Z E before
ceiling erosion 30/17Z W-30/20Z E. Initial N sfc winds light
BNA/CSV to sustained around 14kts CKV will slowly veer SW thru
30/24Z.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION......JB Wright
AVIATION........JB Wright
Area Forecast Discussion
National Weather Service Blacksburg VA
1004 PM EST Wed Dec 29 2021
.SYNOPSIS...
A stalled front continues to waffle back and forth across the region
overnight into Thursday morning. The front combined with an area of
low pressure will keep period of rain in the forecast through at
least Thursday afternoon. The front sinks south of region Thursday
night into Friday before a much stronger storm system follows for
the weekend. Cooler temperatures and drier conditions return early
next week.
&&
.NEAR TERM /THROUGH THURSDAY/...
As of 1005 PM EST Wednesday...
...More much needed rain overnight into Thursday morning as our
stalled front remains. Diminishing rain chances Thursday afternoon..
Current forecast package remains on track with subtle adjustments to
precipitation chances and thunder risk overnight into Thursday
morning.
Pockets of light to moderate rain continue across the Virginia
Piedmont and southern Shenandoah Valley this evening. This first
wave will continue north and east along the front with low
pressure incoming from the Tennessee River Valley. This will
increase rain chances once again in all locations and especially
in areas along the VA/NC line overnight into early Thursday
morning. Models continue to shunt MLCAPE values up to around 250
j/kg along the VA//NC line so left a mention of a rumble or
thunder or two ahead of the incoming low. Overall thunder looks
to be meager with the best instability along the Interstate 40
corridor.
Temperatures hold steady overnight with rain chances slowly
decreasing late Thursday morning into Thursday afternoon as the
front nudges back to the south of our region.
As of 707 PM EST Wednesday...
Increased rain chances and a rumble of thunder overnight into
Thursday morning. Front slowly sags south by Thursday afternoon...
Pockets of light to moderate showers continue to blanket many area
along and west of the Blue Ridge Parkway this evening as our frontal
straddles the area. The front along with an area of low pressure
will be the primary focal points for tonight`s wet weather across
the region. Rain coverage looks to continue to increase overnight
into Thursday morning as low pressure rides east from the Tennessee
River Valley into the central Appalachains.
The front currently remains from Virginia Beach west to
Charlottesville and south toward Bristol. North of the boundary the
air remains fairly stable with temperatures in the low to mid 50s
across the Greenbrier Valley, Alleghany Highlands, and much of
southeast West Virginia. South of the boundary temperatures sit in
the upper 50s and low 60s in areas such as Roanoke/Danville and the
North Carolina Piedmont which is still relatively stable, but does
open up the opportunity for a rumble of thunder overnight into
Thursday morning as a plume of lackluster MUCAPE below 500 j/kg
combined with 0-3km SRH values rides into the southern half of the
forecast region. The really unstable air remains down along the I-40
stretch from Raleigh to Charlotte where air temps and dewpoints sit
in the low to mid 60s. With that said, the Storm Prediction Center
has left a Marginal Risk for severe weather in place for the North
Carolina Piedmont and mountains overnight into Thursday morning.
Current timing on storm development per the HRRR and NAMnest still
looks to be between 10pm tonight and 4am Thursday morning. Localized
damaging winds will be the biggest concerns with any storms
especially with increased low level shear and sfc-500 90-6m) bulk
effective shear values around 45-55 kts.
Low pressure works east Thursday morning with our front starting to
slightly nudge south toward the VA/NC line. Periods of showers will
remain with areas of fog and an isolated thunderstorm possible
south of US-58 and east of US-29 Thursday morning into midday.
Coverage will start decrease by late Thursday afternoon and
evening as the front works further south and east. Portions of
the VA/NC Piedmont will likely hold onto the higher rain chances
the longest which is great news for the impending drought
situation.
Rainfall amounts tonight through Thursday will range from 0.25-0.50
inch areawide. Localized heavier amounts are possible along the Blue
Ridge and across the Piedmont region where more efficient rain can be
found with modeled PWATS upwards of 1.2 to 1.4 inches. HRRR and
NAMnest tend to agree with this with two separate areas of heavy
rain one west of the Blue Ridge across southern West Virginia and
one out east across the Virginia Southside/North Carolina Piedmont.
Temperatures will continue to remain well above normal for this
time year. Highs will range from the upper 50s and low 60s over the
mountains to upper 60s east. If we can get some sunshine Thursday
afternoon we may be able to increase these temperatures by a degree
or two although confidence remains low. Please reference the CLIMATE
section of this document for details on potential record warmth.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 200 PM EST Wednesday...
Short lull Friday, more rain over the weekend.
Frontal boundary will have sunk south of us, paving the way for a
quiet weather day on Friday. As low pressure forms in the southern
plains ahead of a deep eastward tracking trough, the front will be
lifted northward through our area again on Saturday. Widespread rain
will help alleviate some of the drought concerns the Southside and
Piedmont have been facing of late, but doubtful at this time that it
will end the drought entirely. Saturday night will see the front
edge of a cold front approach the Mid-Atlantic as part of the low
pressure system that formed in the plains/Mid-South.
Don`t expect things to cool down until later in the weekend as we
sit largely in the warm sector of the approaching system through
this forecast period. That solid southerly flow will hold
temperatures in the 60s and 70s during the day, as we have become
accustomed to this December. Overnight lows will stay in the 40s and
50s. Saturday night will lean more toward the 40s as rain and
persistent cloud cover will during the day Saturday will help cool
things down a touch.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 200 PM EST Wednesday...
Temperatures drop to winter levels.
A cold front will enter the CWA late Saturday night and transit the
area during the day Sunday. This promises more rain for the daytime,
but overnight as a shock of cold air takes over the region, some of
that precip could turn frozen, especially in the mountains as
upslope snow showers. How much could stick remains to be seen, as
the ground has not gotten the chance to cool down yet this season.
Instead of treating this as a mid-winter event, it will feel more
like an early winter event. Any precipitation, snow or rain, will
cut off quickly as the cold frontal boundary quickly moves east and
takes moisture with it. Surface high pressure and upper zonal flow
dominates the east coast weather pattern early next week. The next
activity we can expect after this weekend could come by Thursday as
most deterministic models bring a low pressure center through the
Great Lakes region, passing another front over us.
Temperatures drop sharply from the well-above normal temps we have
become accustomed to. Temperatures plummet into the 20s and teens
Sunday night, and highs will be held in the 40s Monday. Early next
week things will moderate a bit, but it will be much closer to
normal for early January with subfreezing temps each night.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
As of 715 PM EST Wednesday...
Poor flying conditions expected through Thursday.
As of 00Z (7 PM EST) Wednesday, VFR to MVFR ceilings and VFR
visbilities were observed at all TAF sites. However, there is
high confidence that ceilings will lower to MVFR or even IFR
conditions tonight and linger well into Thursday. There is lower
confidence for pockets of MVFR visibilities due to fog late
tonight and early Thursday morning.
Rain showers across the region this evening should end west
(around 05Z-06Z) to east (around 09Z-10Z). However, a nearly
stationary front will settle across the NC/VA border keeping low
clouds in place through Thursday. There is some uncertainty
whether ceilings will improve by Thursday afternoon, but most
guidance suggests at least MVFR ceilings remain in place for
much of the day Thursday.
.Extended Aviation Discussion...
Through the upcoming weekend, the area will have more than one
opportunity for sub-VFR conditions across the region. Drier
conditions are expected Friday with a stronger system arriving
for the weekend. This system poses the best chance for
widespread precipitation. Drier and colder weather is expected
for Monday.
&&
.CLIMATE...
As of 705 PM EST Wednesday...
With the mild air lingering, record highs and warm lows may be in
reach again for some, especially the warm lows.
Thursday 12/30/2021
Site High Temp/Year Warmest Low/Year Forecast High/Low
Bluefield 68 1990 51 1990 61/50
Danville 76 1984 52 1990 69/55
Lynchburg 71 1996 50 1990 65/52
Roanoke 70 1996 50 2019 66/53
Blacksburg 68 1984 50 1984 64/50
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...ET
NEAR TERM...ET
SHORT TERM...VFJ
LONG TERM...VFJ
AVIATION...DS/PH
CLIMATE...DS/WP
Area Forecast Discussion
National Weather Service Las Vegas NV
800 PM PST Wed Dec 29 2021
.SYNOPSIS...Next storm in our parade of systems will bring more
rain and snow to much of the Mojave Desert and southern Great Basin
today into Friday. Significant snow is possible for the higher
elevations of Lincoln and Clark Counties with winter storm warnings
in place for some areas. The weekend will be dry with cold
temperatures likely for the first few days of 2022.
&&
.UPDATE...Challenging forecast for the next 24 hours which has
already been plagued with slowdowns and surprises. The snow level
across the Owens Valley today started out near the valley floors and
never climbed at all through the day, with Bishop only topping out
at 32 degrees. Snow accumulations exceeded expectations from Bishop
to Olancha, where anywhere from 1-3 inches of snow has been common,
with nearly 6 inches along the Sierra foothills. A winter weather
advisory has been issued for this area through the overnight hours,
though most of the snowfall should wrap up prior to midnight in the
central and northern Owens Valley. The snow and icy roads have
resulted in a few accidents and spin outs, and icy roadways will
remain dangerous until conditions warm up tomorrow.
Further south, a band of broken showers has developed just north and
parallel to the I-15 corridor, but measured precip has only
amounted to a few hundredths or less. The Spring Mountains have been
getting light snow most of the evening, but accumulations thus far
have been light.
Looking forward in time, still anticipating shower chances to spread
south and east overnight, with chances peaking along the I-15
corridor in the morning hours. However, with the upper level energy
splitting across the region (part of the shortwave diving offshore of
SoCal while the other lifts into the central Rockies), dynamic
support for widespread precipitation will be minimal. Alternatively,
precipitable water values will remain anomalous, so we may end up
with an abundance of clouds and a very light, broken band of
showers, but meager rainfall totals outside of upslope favored
terrain. Some of the latest HRRR guidance has suggested this
outcome, along with several HREF members.
Have updated the forecast to account for trends and fine tune the
snow level across Inyo County. The latest PoPs have also trended
downward slightly for the deserts as well as slowed down the timing
for best precipitation chances. The forecast should hit the web
shortly.
-Outler-
&&
.SHORT TERM...Through Thursday night.
Latest radar imagery showing precipitation spreading into western
portions of Inyo County including the southern portions of the Death
Valley National Park. Snow have been off and on this morning and
early afternoon over portions of the Owens Valley where up to a
couple of inches of snow has been observed. Elsewhere, there really
hasn`t been much else other than some light snow reported on the
Spring Mountains. The trend through the remainder of the afternoon
will be for precipitation to increase across Inyo, Nye and Lincoln
Counties. The latest hires models continue to show a band of
rain/snow setting up from Inyo through Lincoln Counties through much
of the overnight period before finally shifting south and impacting
San Bernardino, Clark, and Mohave Counties during the day Thursday.
Due to the southwest to northeast flow, this should allow for
excellent upslope precipitation over the Spring Mountains and we are
still looking for about 10-20" of new snow to fall by Thursday
afternoon. Snow levels are expected begin this afternoon between
4000-4500 feet, but rise to 4500-5000 feet by Thursday morning and
rise even more by Thursday afternoon. Although the latest hires
models continue to show precipitation over much of the area through
Thursday, overall it seems more broken and more scattered than
widespread. Think that overall snow totals and rain totals will be
lower than previously thought. Even though snow amounts in the
Winter Storm Warning areas may be lower than previously thought, we
should still see enough to warrant the current warnings in place and
will not make any changes at this time. No significant winds are
expected through Thursday, except southerly gusts up to 30 mph are
possible in the Colorado River Valley.
.LONG TERM...Friday through Tuesday.
Lingering precipitation chances will persist on Friday, mainly
across Northwest Arizona as the low pressure system offshore lifts
into northern Baja and across southern Arizona. Meanwhile, one
final shortwave will dig southward into the Great Basin on its way
to the central Rockies. This feature previously was advertised to be
a bit stronger but has trended more progressive and further north,
which may spare us a blast of gusty north winds for NYE. For now,
light northerly breezes are forecast NYE night, followed by slightly
stronger winds focused down the Colorado River Valley Saturday.
A much cooler, continental airmass will spill into the region over
the weekend, with high temperatures 8-10 degrees below normal, and
below freezing morning low temperatures likely across nearly the
entire forecast area. The cold temperatures may flirt with hard
freeze criteria near Kingman, where lows near 20 are expected by
Sunday morning. Otherwise, a much deserved break from the action is
expected with a ridge of high pressure building over the western US
which will last through at least the beginning of next week.
&&
.AVIATION...For Harry Reid...Winds have remained light and variable
through the morning into the early afternoon. I am still expecting
winds to come around to a more southerly direction by 00Z, and then
remain southerly through the night. CIGS will continue to lower
through the afternoon to around 5kft by this evening. Lower CIGS to
around 3kft in shower activity overnight can be expected, and there
is a chance that CIGS cloud lower to 1.5kft in heavier rain late
tonight and Thursday morning.
For the rest of southern Nevada, northwest Arizona and southeast
California...Southerly winds are expected at most sites into this
evening. CIGS will continue to lower at most sites with the
exception of KBIH where low CIGS and precip are already occuring.
All sites will see the chance of showers overnight and Thursday with
the exception of KBIH where precipitation should tapper off by
Thursday morning.
&&
.SPOTTER INFORMATION STATEMENT...Next system slated to produce heavy
snow in our mountains, as well as rain in our valleys. Spotters are
encouraged to report any significant weather or impacts according to
standard operating procedures.
&&
$$
SHORT TERM...Gorelow
LONG TERM...Outler
AVIATION...Planz
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