Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 01/13/24
Area Forecast Discussion
National Weather Service Glasgow MT
435 PM MST Fri Jan 12 2024
.DISCUSSION...
EARLY EVENING UPDATE:
Made adjustments to the PoP grids to account for ongoing lake-
effect snowbands due to northwesterly fetch along the Dry Arm and
other inlets along the southern shore of Fort Peck Lake. Thus,
this added light snow showers in the Weather Grid overnight for
areas downstream of these northwesterly fetches.
-Enriquez
PREVIOUS DISCUSSON:
Arctic air mass is firmly in place across the region with the
disturbance that brought the snow last night pushing east this
evening. Little to no temperature recovery today and with partial
to full clearing overnight, expect the temperatures to take a
nosedive, potentially seeing some of the coldest readings in the
last 5 to 10 years in some areas. Confidence in the cold
temperatures was enough to use the NBM10 for tonights lows, with
widespread temps between -30 to -40 tonight. Expecting not much in
the way of temperature recovery tomorrow and tomorrow night`s lows
will be about the same as tonight`s. Slowly the Arctic High starts
sliding south early next week but it`s lingering long enough where
the Wind Chill Warning currently in place has been expanded to 18Z
11am) Monday.
At this time it looks like we break zero for highs on Tuesday, but
still remain well below average next week with highs in the single
digits to teens. It looks like the next chance for snow will be
Tuesday evening with unsettled weather lasting into Thursday night
or Friday morning. Confidence is still low on timing or snowfall
amounts. Will keep you posted.
-Bernhart
&&
.AVIATION...
UPDATED: 2130Z
CAT RANGE: IFR - MVFR, VFR possible western zones
DISCUSSION: Although the general band of snow is expected to push
out of the area tonight, lingering clouds and occasional flurries
may be possible overnight with expected clearing tomorrow. Blowing
snow at times may also lead to reduction in visibility.
EXTREME COLD: Temperature lows tonight and tomorrow night are
expected to be in the -30 to -40 range with highs only recovering
into the -10 to -20 range on Saturday and Sunday afternoons. This
will lead to problems for airport and aircraft equipment as well
as be hazardous to any ground personnel working outside.
WIND: NW 10-20 kts
-Bernhart
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
Wind Chill Warning until 11 AM MST Monday for Central and
Southeast Phillips...Central and Southern Valley...Daniels...
Dawson...Eastern Roosevelt...Garfield...McCone...Northern
Phillips...Northern Valley...Petroleum...Prairie...Richland...
Sheridan...Southwest Phillips...Western Roosevelt...Wibaux.
&&
$$
weather.gov/glasgow
Area Forecast Discussion
National Weather Service Pittsburgh PA
748 PM EST Fri Jan 12 2024
.SYNOPSIS...
Mixed precipitation continues through this evening, with much
colder air and all snow then returning early Saturday. Gusty
conditions will continue through Sunday. Cold temperatures will
continue through much of next week.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
KEY MESSAGES:
- Gusty conditions are expected into Sunday.
- Snow will transition to rain near I-80 over the next few
hours as warm air surges into the region from the south.
- Advancing cold air from the west will increase snow chances
after 2am in eastern Ohio, after 4am for the Pittsburgh
metro.
-----------------------------------------------------------------
7:30PM Update: A noted dry slot on GOES-16 low-lvl water vapor
is currently advancing through eastern Ohio. Precipitation
intensity will decrease from west to east over the next 3 hours.
However, winds gusts will continue to remain high with an
intensity pressure gradient lingering. At 7:06pm a gust of 69
mph was noted at KERI. Snow intensity along I-80 has reduced
significantly over the last hour, KFKL has increased in
visibility from 2 miles to 6 miles. Warm air surging from the
south will likely transition snow to rain or a rain/snow mix. A
new special weather statement for isolated icy road conditions
will not be needed in the near term.
Previous Discussion...
A large, deepening low pressure system will cross from the
Midwest into the Great Lakes region by tonight, spreading
precipitation across our area this afternoon and evening. Warm
advection has already begun ahead of this system, with latest
PIT ACARS soundings showing a warm nose around 800mb already
approaching 4C. Soundings also show a substantial dry layer in
place, which will be critical to initial precip types.
As precipitation overspreads the area later this afternoon,
wet-bulbing through the dry air should allow sleet and snow to
mix in for areas north of Pittsburgh (accumulating primarily
north of I-80) and across the ridges. This initial accumulation
will be fairly brief as warm advection wins out and returns
precipitation to all rain before midnight. Accumulations of 1 to
3 inches are possible, with highest amount likely across
portions of Venango, Forest, Clarion, and Jefferson counties.
For now, confidence in snow amounts of 3+ inches is low, but
will re-evaluate through today for the possibility of a Winter
Weather Advisory for these areas.
As the surface pressure gradient tightens and winds aloft
strengthen, winds will rapidly intensify this afternoon.
Strongest gusts (up to 65 mph) are expected in the ridges, where
a High Wind Warning is in effect through 10pm (through 1am
Sunday for eastern Tucker). With the exception of eastern
Tucker, this will be downgraded to a Wind Advisory from 10pm
through 1am Sunday. For the lower terrain, a Wind Advisory for
gusts up to 50 mph begins at 4pm this afternoon and continues
through 1am Sunday. NBM probabilities for >45 mph gusts are
generally 50-70% late this afternoon and evening west of the
ridges. Probabilities for wind gusts >50mph over the warning
area are 70-80%, with some of the higher peaks seeing 50-60% for
>60mph.
Widespread precipitation will quickly end by around midnight
as a large dry slot crosses the area, though light rain and
snow showers may linger. This break will be short-lived,
however, as a strong shortwave trough will cross the region
early Saturday along with a push of much colder air. This will
return light snow showers areawide.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY/...
KEY MESSAGES:
- Wind advisory remains in effect through Saturday night.
- Snow showers, very cold temperatures and wind chills are
expected through the weekend.
-----------------------------------------------------------------
Light snow showers will continue through Saturday, waning
overnight Saturday into early Sunday. Southwesterly flow
through the period will limit upsloping and lake effect.
Accumulations are expected to be minor, with highest amounts of
long-duration 2-4 inches expected across the ridges. The I-80
corridor may see 1-2 inches, with less than an inch expected
elsewhere.
Strong winds will continue through Saturday, waning Saturday
night. Thus, the Wind Advisory continues through 1am Sunday.
Gusty winds are still expected on Sunday, but probabilities for
advisory criteria are low.
Cold advection will weaken Saturday afternoon, but little
increase in surface temperature is expected. Highs for the day
will be at midnight, with afternoon temperatures ranging from
the upper 20s to lower 30s. Gusty winds will drop wind chill
values into the teens to single digits.
The next trough and burst of arctic air will move through the
region on Sunday. Although this air will be even colder, it will
also be drier and due to the position of the trough, our winds
will remain out of the west rather than northwest. We could
actually see some improvement as far as decreasing cloud cover
Sunday afternoon, but it will be very cold with wind chills in
the single digits all day. With ongoing strong cold air
advection, steady or slowly falling temperatures are possible
again during the day Sunday.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
KEY MESSAGES:
- Cold air through the end of the forecast period.
- Light snow event possible Tuesday.
___________________________________________________________
Low temperatures are forecast in the teens Sunday night,
potentially dipping into the single digits come Tuesday morning.
Additional snow chances will approach from the south late Monday
into Tuesday, but impacts from this storm will depend on track
and intensity: both of which are highly uncertain at this time.
NBM high temperatures next Tuesday range from as low as the
single digits on the low end (10th percentile) to the upper 20s
and lower 30s on the high end (90th percentile). Considerable
model spread in precipitation and temperature is related to
uncertainty in the position and amplitude of an eastern trough.
Nonetheless, the region is favored to remain below average
through day seven. CPC outlooks show this cold pattern may
persist through the mid-to-late January.
Wednesday and Thursday will feature high pressure tracking
through the region with dry weather. Wednesday morning is likely
to be the coldest of the period, with single digits possible.
Cold temperatures will remain through the week.
&&
.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
Strong low pressure will continue to track across the Great
Lakes region tonight. Steady rain ahead of the low was beginning
to taper off from W-E across the region, though additional
showers are expected as the low pulls an occluded front across
the region overnight. Expect VFR, with patchy MVFR conditions in
the showers, to continue. Wind has begun to diminish as mixing
heights decrease, though gusts from 25-35kt are still expected
through the evening. With the decrease in mixing, included a
period of LLWS in the tafs with a strong low level jet overhead.
Southeast wind should shift to the SW as the occluded front
crosses the region overnight. MVFR cigs are expected behind the
front. Winds should increase again with the passage of the
front, with frequent gusts from 40-45kt expected later tonight
through much of the day Saturday. A tight pressure gradient, and
steepening lapse rates in cold advection, should maintain these
gusts.
An upper low/trough is then progged to cross the Great Lakes
and Upper Ohio Valley region Saturday, with scattered snow
showers. MVFR cigs should continue through the day, with
occasional MVFR-IFR reductions in vsby with the snow showers.
.OUTLOOK...
A series of troughs rotating around the upper low will maintain
periodic snow and restriction potential through Tuesday. VFR is
possible again Wednesday as weak high pressure briefly builds
across the region.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...Wind Advisory until 1 AM EST Sunday for PAZ007>009-013>016-
020>022-029-031.
High Wind Warning until 10 PM EST this evening for PAZ073>078.
Wind Advisory until 1 AM EST Sunday for PAZ073>078.
OH...Wind Advisory until 1 AM EST Sunday for OHZ039>041-048>050-
057>059-068-069.
WV...Wind Advisory until 1 AM EST Sunday for WVZ001>004-012-021-509.
High Wind Warning until 10 PM EST this evening for WVZ510>513.
Wind Advisory until 1 AM EST Sunday for WVZ510>513.
High Wind Warning until 1 AM EST Sunday for WVZ514.
&&
$$
SYNOPSIS...Rackley
NEAR TERM...Rackley
SHORT TERM...Rackley
LONG TERM...Rackley/22
AVIATION...WM