Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 10/09/19
Area Forecast Discussion
National Weather Service Hastings NE
703 PM CDT Tue Oct 8 2019
.SHORT TERM...(This evening through Wednesday)
Issued at 338 PM CDT Tue Oct 8 2019
Aloft: Aircraft winds and animations of RAP tropopause analyses
indicated low-amplitude zonal flow over the Cntrl/Wrn CONUS. A
small shrtwv trof was over the NEB Panhandle and CO and was moving
E. This trof will cross NEB/KS tonight with nothing more than
some high clds. The bigger story is the deep trof sinking into the
Pac NW from SW Canada. 500 mb heights fell as much as 160 m over
WA from 00Z- 12Z. The longwave flow will amplify tonight and
tomorrow as heights cont to fall with the SW Can trof dropping
into the Nrn/Cntrl Rckys.
Surface: 1027 mb high pres was over the Ern GtLks. An
unseasonably strong cold front extended from Cntrl Canada SW into
the Pac NW. The high will strengthen as it heads into Ern Canada
thru tomorrow. Meanwhile...a very cold air mass and its cold front
will cont to spread S and E. By 00Z/Thu...the front is fcst to
extend from MN thru the NEB Sandhills thru Nrn CO...with a strong
1034 mb high over MT.
Rest of this afternoon: Sunny...breezy and seasonably warm. Temps
will are peaking right about now.
Tonight: Mostly clr to partly cldy as some patches of
cirrostratus move thru with the shrtwv trof. A mild night. Temps
10F above normal.
Maintained a low (20%) POP for isolated shwrs/tstms toward dawn
over the far SE fringe of the CWA...associated with WAA and modest
low- lvl mstr return.
Wed: Possibly a leftover shwr/tstm during the AM far SE fringe.
Otherwise mostly sunny...but turning partly cldy. Still seasonably
warm and breezy.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 338 PM CDT Tue Oct 8 2019
Aloft: The deep trof over the Nrn/Cntrl Rckys at 00Z/Thu will
slowly progress E Thu with a low dvlpg over WY. This low will
cross NW NEB Thu night on its way into MN where it will stall over
MN Fri-Sat due to a downstream block over the NW Atlc. The low is
then fcst to creep NE into ON Sun-Mon. In its wake...cyclonic NW
flow will remain over NEB/KS thru Sat. By Sun its effects on the
rgn should decrease as deamplification occurs. Global mdls cont to
indicate a wk shrtwv trof will be migrating thru the Wrn USA.
This trof should cross NEB/KS Mon...with more cyclonic WNW flow in
it wake Tue.
Surface: Lee cyclogenesis will commence Thu eve over CO. This low
will eject into KS by 12Z/Thu. This low will move N along the
front as it crosses the CWA Thu while 1036 mb high pres over the
Rckys begins building in. The low will move into MN Thu night and
stall thru Sat night as it occludes. The circulation around the
low should finally release its influence on NEB/KS Sat. A wk low
is fcst to form over CO Mon and head E acrs KS. Anticyclogenesis
is then fcst Tue with strengthening high pres emerging from the
Nrn Rckys onto the Plns.
Temps: Very mild for most of Wed night ahead of the front...but
temps will plunge after the front moves thru. That will cont into
Thu AM with temps holding steady 35-45F in the afternoon.
Continued much colder than normal Fri with highs 25-30F below
normal. Back into the 50s Sat-Tue...with low-mid 60s SW fringe.
Cold: It will only take 1 night of this kind of cold to end the
growing season...but 2 hard freezes will occur back-to-back Fri
and Sat mornings over most of the CWA (28F or colder). It is
likely that Ord and Greeley will see freezes 4 if not 5
consecutive nights/mornings per the last svrl runs of MEX MOS.
It`s now in our official fcst.
Wind Chills: Anyone outdoors Fri AM will need winter wx gear.
WCI`s will range from the low teens to low 20s with howling NW
winds.
Winds: NW 20-35 mph Thu-Fri...gusting 40-50 mph in strong CAA
with downward transfer from 4K ft. GFS mixing heights and winds
are higher/stronger than the NAM.
Refreshed and resent the SPS at 1943Z highlighting cold/wind
chills/winds.
Precip: With the upr low remaining NW of the CWA...we will be
dealing with the dry slot. Therefore...decided to place more of
an emphasis on patchy drzl Wed night into Thu...which could turn
to frzg drzl Thu night. Precip will struggle to form over the CWA
with this system. Can`t completely rule out some shwrs and sub-
svr tstms...but it`s not looking good. The low-lvl mstr will
create conditional instability...but will shwrs and tstms actually
dvlp? The mstr will be shallow. Given that...it`s psbl even the
meager mention of snow that we have in the fcst may be overdone.
Based on past experience and mdl RH cross sections...when precip
occurs Thu night it could be patchy frzg drzl psbly mixing with or
briefly changing to very light snow (snow grains) at times when
slightly deeper mstr bands move thru. Believe the shallow NAM RH
is probably more realistic vs GFS. Some leftover snow flurries may
linger in a few spots Fri.
Overall...precip amts will be very minor with this system.
Dry wx currently expected Sat thru next Tue.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Wednesday)
Issued at 645 PM CDT Tue Oct 8 2019
Strong low level wind shear will be the primary aviation concern
tonight with a strong low level jet of 40-45 kts. VFR conditions
are expected through Wednesday morning and then we could start to
see MVFR ceilings working into some areas Wednesday afternoon,
primarily around KGRI and points east from there. It will be
breezy throughout the forecast period with the wind remaining
southerly to south southeasterly.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
SHORT TERM...Kelley
LONG TERM...Kelley
AVIATION...Wesely
Area Forecast Discussion
National Weather Service Blacksburg VA
749 PM EDT Tue Oct 8 2019
.SYNOPSIS...
High pressure will remain wedged against the eastern face of
the mountains through the end of the workweek, resulting in
continued cool east-northeasterly wind flow across the mid-
Atlantic. With the departure of a passing upper level
disturbance this evening, drier conditions with begin to return
on Wednesday. Another cold front will pass across the central
Appalachians on Saturday, resulting in another round of showers
and showers.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
As of 330 PM EDT Monday...
The big story for today has been the persistent band of
beneficial rain which, anchored across the mountains for most of
the morning, is drifting slowly eastward across the foothills
into the Piedmont during the afternoon. This band is being fed
by Atlantic moisture transported in the northeasterly windflow
around high pressure wedged against the mountains. This same
moist windflow is what has kept a lid on afternoon heating, as
3 PM temperatures remain in the 50s across the mountains,
though they`ve managed to rise into the low/mid 60s across the
Piedmont.
The band of rain is forming along the deformation zone of a low
pressure system drifting off the Carolina coast. Weather
forecast models have been too fast in anticipating the coastal
low pressure pushing northeast and, as such, the timing of when
this rain will taper off during the evening as upper level
support exits the area. Kept high rain chances in the forecast
for at least the northern Piedmont through the 9-10PM timeframe
before rainfall decreases, though its possible that current
rainfall may linger into the early hours of Wednesday before it
finally exits the area. Otherwise, expect widespread cloud cover
overnight with perhaps only a 5-7 degree drop from Tuesday
afternoon highs. Overnight lows will hold in the 50s for most of
the area. Continued northeasterly flow will support pockets of
drizzle and a sprinkle or two, in additions to patches of fog.
The high pressure wedge will remain in place for Wednesday,
though upper level ridging will begin to build over the
Mississippi River Valley. As such, expect drier conditions, with
some breaks of sunshine developing by late morning mainly
across the mountains. Wednesday afternoon temperatures will be
warmer than those observed on Tuesday, but continued the trend
of undercutting guidance by a couple degrees given the
northeasterly flow and the introduction of moisture back into
the ground where it occurred.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 233 PM EDT Tuesday...
A slowly moving upper level low will deepen off the Mid-Atlantic
Coast and drift north into Friday night. Upper trough in the Rockies
will deepen and lift northeast reaching the Midwest and Western
Great Lakes by Saturday morning. The associated cold front will
travel eastward and be position along the western slopes of
Appalachian around Saturday morning. Meanwhile, The upper ridge
of high pressure over the Southeast will build northward into the
Ohio Valley.
The forecast area will be influenced most by this upper ridge with
limited potential for precipitation and moderating temperatures
through Friday.
Some patchy light rain or drizzle may be possible Wednesday night in
the mountains especially along the crest of the southern Blue Ridge
as low level flow maintains a northeast to east trajectory on the
west side of the low off the East Coast. Low temperatures Wednesday
night will range from the mid 40s in the mountains to the mid 50s in
the piedmont.
After morning cloudiness, sunshine will return for Thursday
afternoon with above normal temperatures. High temperatures Thursday
will vary from the mid 50s in the mountains to the lower 70s in the
piedmont. Mostly clear conditions Thursday night will allow
temperatures to drop into the mid 40s in the colder mountain valleys
to the lower to 50s in the piedmont. Under high pressure Friday,
high temperatures will moderate to the upper 60s in the wet to the
mid 70s in the east.
The upper ridge will start to break down by Friday night with the
approach of a cold front. There may be enough moisture along the
frontal boundary for isolated showers to reach the far western
portion of the forecast area by daybreak Saturday. Low temperatures
Friday night will range from the upper 40s in the mountains to the
mid 50s in the piedmont.
Confidence in the above portion of the forecast is moderate.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 233 PM EDT Tuesday...
An anonymously deep upper low will very slowly lift through the
Great Lakes through the weekend and travel northeast reaching
southeast Canada by Monday night into Tuesday. In general, heights
will lower over the Mid Atlantic region.
A shallow surface wedge may hold into Saturday. A cold front will
drop southeast across the region Saturday afternoon into Saturday
night. Isolated to scattered showers may be possible with frontal
boundary. The best chances of rain will be in the west. High
pressure will build into our region Sunday and travel east Monday
into Tuesday. Another shortwave will rotate around the upper trof
Tuesday afternoon into Wednesday.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
As of 745 PM EDT Tuesday...
The area will remain under the influence of a high pressure
wedge through the period. Showers should be ending gradually
overnight as short wave energy pulls out and and isentropic
lift decreases, but anticipate IFR/LIFR conditions will linger
west of the Blue Ridge until improving to VFR by mid morning
Wednesday. All guidance is strongly suggesting that some higher
cigs will push in from the northeast and can see better flight
conditions do exist upstream. Will indicate an improvement to
MVFR then gradually to VFR but confidence in this scenario is
marginal so will watch closely for hints that a more pessimistic
solution is required.
Winds will generally be light with little impact to aircraft
operations.
.Extended Aviation Discussion...
With the departure of low pressure off the Mid-Atlantic coast,
expect improved flying conditions into Thursday and Friday as
high pressure remains situated across the mid-Atlantic region.
Another cold front will pass across the central Appalachians on
Saturday, resulting in scattered convection, as well as sub-VFR
conditions.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...NF
NEAR TERM...NF
SHORT TERM...KK
LONG TERM...KK
AVIATION...MBS/NF
Area Forecast Discussion
National Weather Service Great Falls MT
832 PM MDT Tue Oct 8 2019
.SYNOPSIS...
A strong cold front will continue north to south through the
region this afternoon and evening, bringing much colder
temperatures and accumulating snowfall that persists overnight and
through the day on Wednesday. Snow tapers off Wednesday night
with mostly dry conditions but continued cold temperatures late in
the week.
&&
.Evening Update...
Evening update has been published, with generally minor adjustments
made to nudge hourlies (winds/temperatures/relative humidity/sky
cover/PoPs) to current observations, radar trends, and latest
guidance. Did lower overnight low temperatures several degrees
further than the previous forecast as observations have been
trending cooler. In addition, made tweaks to PoPs to expand areal
coverage of higher values based on radar coverage/trends.
Moderate to at times heavy snow continues to move across Northern
and Central Montana early this evening, with precipitation filling
in over the past several hours across portions of Southwest
Montana. Visibilities have fallen to as low as 1/4 to 1/2 mile in
the heaviest burst of snow this evening, which has led to
significant reductions in visibilities at times. With the loss of
daylight and solar insolation; road surfaces have cooled
significantly, which has allowed for snow to accumulate rapidly on
roadways. Additional accumulating snow on roadways will create
hazardous travel conditions throughout the night, thus no changes
were made to the ongoing Winter Storm Warnings (outside of
updating "additional snow amounts"). Have decided to issue a
Winter Weather Advisory for Eastern Teton, Chouteau, Hill, and
Blaine counties until noon on Wednesday as snow has been slow to
move out of the area and reports of snow covered roadways have
been reported (also radar imagery and latest guidance suggests
that another 1-3" of snow is possible over lower elevations of
portions of the counties). - Moldan
&&
.AVIATION...
Updated 615 PM MDT Tues Oct 8 2019 (09/00Z TAF Period)
Begin this TAF period with VFR conditions at KBZN, KEKS and KWYS,
with MVFR to LIFR at all other airfields. By 04Z, conditions at
KBZN, KEKS and KWYS degrade, as well. Obscurations include -SHSN BR
and -SHSN BLSN. Mountains will be obscured. Some locations will
experience gusty winds. LLWS is forecast at KWYS. Expect turbulence
to develop. Additionally, aircraft icing will occur in cloud and in
precip.
- Fogleman
&&
.PREV DISCUSSION...
/ISSUED 615 PM MDT Tue Oct 8 2019/
Today through Wednesday night...
The forecast remains on track for the cold front to continue
dropping southward and into the Bozeman area by late this
afternoon/evening. Expect gusty west winds to shift more
northerly along with quick drop in temperatures, once the front
passes through. Widespread snow will continue to spread south
lagging several hours behind the frontal passage. Best chances
for snow tonight will be from Great Falls to Lewistown and
southward this evening. Moderate to brief heavy snow at times
with gusty winds bringing some blowing snow is likely at times
through tonight over central and SW MT. Snow then looks to
diminish later in the day through the evening Wednesday. Forecast
snowfall amounts have changed little from previous forecasts and
still expecting about foot of snow across the Rocky Mountain Front
and the central and southwestern mountains, with 1 to 4 inches
across northern and central portions, and 6 inches or more across
the southwest and some central areas such as Judith Basin and
Fergus County. No changes were made to the current Winter Storm
Warning highlights as everything still appears to be on track.
Thursday through next Tuesday...
Upper level trough shifts east into the Northern Plains states on
Thursday with an upper level ridge building in behind it over the
The Northern Rockies through the upcoming weekend. After the snow
ends Wednesday evening, a relatively dry period is expected through
the weekend. Thursday morning temperatures will fall to the single
digits and low teens across most of the forecast area as skies clear
Wednesday night with a fresh snow cover in many areas. This will be
close to record lows for the date in several locations, but
interestingly, October 10th records are lower than surrounding dates
from a cold snap the some may remember in 2009 where the minimum
temperature fell to 4F at Great Falls and as cold as -16F at a
location 11 miles SW if Utica. Similar conditions will be in place
this Wednesday night/Thursday morning, and could result in
temperatures still lower than current forecasts. Temperatures remain
below seasonal averages for this time of year but do gradually
recover through weekend with afternoon temps warming to around 50 by
Sunday at lower elevations.
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 17 27 8 33 / 100 80 30 0
CTB 12 26 7 35 / 80 40 0 0
HLN 21 28 7 34 / 100 90 30 0
BZN 22 28 6 28 / 100 90 50 10
WEY 22 30 2 29 / 90 90 40 0
DLN 20 24 5 28 / 90 90 30 10
HVR 22 34 15 38 / 70 40 0 0
LWT 18 24 7 25 / 100 100 50 10
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until midnight MDT Wednesday night
Broadwater...Central and Southern Lewis and Clark...Jefferson.
Winter Storm Warning until midnight MDT Wednesday night
Gallatin...Madison.
Winter Storm Warning until midnight MDT Wednesday night
Cascade...Fergus...Judith Basin...Meagher.
Winter Storm Warning until 9 AM MDT Wednesday Eastern Glacier...
Northern Rocky Mountain Front...Southern Rocky Mountain Front.
Winter Weather Advisory until noon MDT Wednesday Blaine...
Chouteau...Eastern Teton...Hill.
Winter Storm Warning until 6 PM MDT Wednesday Beaverhead.
&&
$$
http://www.weather.gov/greatfalls