Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/06/22
Area Forecast Discussion
National Weather Service North Platte NE
643 PM CDT Wed Oct 5 2022
...UPDATED AVIATION DISCUSSION...
.SYNOPSIS...
Issued at 358 PM CDT Wed Oct 5 2022
H5 analysis this morning had a closed low off the coast
of the Delmarva Peninsula. A ridge was located west of this feature
and extended northeast from the lower Ohio Valley into the eastern
Great Lakes. West of this feature, closed low pressure was located
over northwestern Iowa. A trough extended southwest of this feature
into southeastern Nebraska. A secondary shortwave trough was located
over southwestern New Mexico. Further west, ridging extended from
central California, north into the Idaho Panhandle. Skies were
partly to mostly cloudy this afternoon across the area. With
northwesterly winds of 10 to 20 MPH, 3 PM CT temperatures ranged from
69 at Gordon, to 76 at North Platte.
&&
.SHORT TERM...(This evening through Thursday night)
Issued at 358 PM CDT Wed Oct 5 2022
A strong cold front will approach northern Nebraska tonight, then
track across western and north central Nebraska on Thursday. For
tonight, expect mainly clear skies with winds becoming more
northerly across far northern Nebraska toward morning. The latest
NAM12 and GFS solns have the front entering far northern Nebraska
by 12z Thursday morning. Overnight lows will bottom out in the
lower to middle 40s. On Thursday, a strong cold front will pass
through most of the area by 21z Thursday. Winds behind the front
will be northerly with a northeasterly shift in winds late in the
day. Temperatures will vary widely across the area on Thursday.
With the morning passage of the front, temperatures will struggle
to rise out of the middle 50s north of highway 2. Further south,
the afternoon timing of the fropa, will allow highs to reach near
70 south of I-80. Thursday night into Friday will prove to be the
most impactful and difficult portion of the forecast. Beginning
Friday night, as the surface front backs west into the Panhandle,
then front range of Wyoming and nern Colorado, favorable mid and
upper level lift will approach, then track across the forecast
area from the northwest. The latest NAM12 and GFS solns, along
with the 12z HRRR (to 12z Friday), develop a distinct northwest to
southeast oriented band of precipitation across the forecast
area. ATTM, the NAM12, 12z HRRR, NAMNEST, and GEFS ensembles have
this band of precipitation from Sheridan county, south
southeastward into Lincoln, SW Custer and Frontier counties.
Impacts to the forecast which hinge on the location of
this band are two fold. First: Cross sections taken perpendicular to
the strongest mid level frontogenesis, indicate strong short
duration vertical lift (possibly convective) within the band.
Temperatures will fall off to the middle to upper 30s Friday morning
in central and western Nebraska. Normally not a huge concern for
snow, however, if the strong vertical lift materializes, we could
see some good dynamic cooling in the most intense areas of
precipitation. This may lead to some wet snow from 3 AM-9 AM MT
Friday morning. As for impacts from this snow, winds will be light
so no blowing snow is expected. However, there may be some threat
for localized, brief, moderate to possibly heavy bursts of snow. As
better forecast confidence in the location of the band and if the
models continue to trend toward stronger mid level lift, we may need
to trend our hazards messaging more toward the threat for snow
Friday morning.
Second: The location of the band will influence cloud cover and the
threat for frost/freezing temperatures Thursday night. ATTM, feel
the best confidence in this occurring is over the far northeast.
That being said, went ahead and trended temps downward utilizing a
blend of NBM, with MET and MAV guidance (which was 27 and 29
respectively for KONL). The NBM kept temps slightly elevated vs. the
statistical guidance. This seemed like a good compromise if the GFS
were to verify and clouds were to be more prevalent in the NERN CWA.
Precipitation will shift southeast into southwestern Nebraska late
Friday morning, before exiting the area Friday afternoon.
Temperatures should warm by late morning into the upper 30s/lower
40s, mitigating the threat for snow. Temperatures will remain very
cool Friday as cloud cover will be prevalent across the area. Highs
will only reach into the upper 40s to around 50.
.LONG TERM...(Friday through Wednesday)
Issued at 358 PM CDT Wed Oct 5 2022
Skies will gradually clear across the north and eastern forecast
area and feel fairly confident in widespread frost and freezing
temps. Further west and southwest, clouds may linger into Saturday
morning, limiting frost potential along and south of Interstate
80. Cloud potential will need to be monitored closely as this will
factor into frost development or not in SW Nebraska. Beyond
Friday night, we should see dry northwesterly flow through Monday.
An upper level low and trough will deepen across the
intermountain west toward the middle of next week. This will lead
to southwesterly flow aloft and some moisture return to the area.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 642 PM CDT Wed Oct 5 2022
A strong cold front will move through western and north central
Nebraska tomorrow morning, causing winds to shift to the north and
northeast between 10 and 15 knots. MVFR ceilings will develop in
northern Nebraska including KVTN between mid-morning and the early
afternoon as this happens. Otherwise, VFR conditions are
expected.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Buttler
SHORT TERM...Buttler
LONG TERM...Buttler
AVIATION...Meltzer
Area Forecast Discussion
National Weather Service Marquette MI
810 PM EDT Wed Oct 5 2022
.SHORT TERM...(This evening through early tonight)
Issued at 133 PM EDT WED OCT 5 2022
GOES Water Vapor imagery and RAP analysis show a mid-level low
slowly progressing through the Dakotas and into Iowa. A surface
boundary dropping into western Lake Superior is supporting cloud
cover over western Upper Michigan and some light radar
reflectivities are starting to pop up over the far west and west of
the Keweenaw. Some additional development will be possible along
this boundary this afternoon and evening as it presses eastward.
Further upstream, a shortwave and surface front are moving into
northwestern Minnesota will be the focus for the next round of
showers, mainly after midnight tonight and into Thursday.
.LONG TERM...(Thursday night through Wednesday)
Issued at 314 PM EDT WED OCT 5 2022
Below normal temperatures prevail throughout the extended forecast
period with near normal precipitation along the lakeshores to below
normal precip away from Lake Superior.
A seasonably strong cold front tracks southeast across our area
shortly after midnight with a secondary surface trough following a
few hours later. Winds increase behind the initial front, but the
secondary feature brings cooler air, deeper mixing, and stronger
winds during the daylight hours on Thursday. This should result in a
non-diurnal temperature curve with falling temperatures, especially
during the afternoon hours. In terms of precip chances, there could
be a few pre-frontal shower but showers are much more likely along
the initial cold front. There is some weak pre-frontal instability
(~250 J/kg), but think it`s insufficient for thunderstorms. Behind
the front, CAA saturates low levels resulting in lake effect clouds
and primarily orographic showers until colder air arrives behind the
secondary trough. Mid-levels are dry while lake effect precip is
ongoing indicating a pure lake effect environment. In general, the
lake effect environment is characterized by inversions around 3-4
kft with a briefly higher values up to 5 kft possible. Thermal
profiles suggest pure rain until Thursday night when our higher
elevation locations should mix with if not changeover to
graupel/snow. Marginal temperatures and light to moderate precip
rates suggest little if any accumulation that would be confined to
grassy/elevated surfaces.
Lake effect showers gradually end from west to east on Friday as the
surface ridge axis moves overhead. Friday night`s temperature
forecast is tricky, because there`s potential for much colder
temperatures if clear skies/calm winds materialize. However, with
the surface ridge positioned well to our southwest over the Central
Plains, mixing may limit nocturnal cooling. The pressure gradient
strengthens on Saturday between the ridge to our SW and a low near
James Bay, which may result in some low-end westerly gales. A weak
cold front follows later on Saturday with surface ridging providing
more tranquil weather through early next week. An amplified pattern
develops by the middle of next week as deep troughing moves into the
Pacific NW sending a much warmer air mass our way.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 810 PM EDT WED OCT 5 2022
VFR conditions will prevail into tonight with abrupt deterioration
in the Thu 06-09Z time frame as a cold front tracks through the
region. TAFs will quickly deteriorate to IFR levels, especially at
KIWD and KCMX with onset of rain. Would not entirely rule out LIFR
conditions, but confidence is not high enough at this time to
mention CIGS that low. Northerly winds will also be an impact early
tomorrow morning at KCMX and KIWD in the wake of the front with
sustained speeds in the 12 to 18 kt range and gusting as high as 30
kts at KCMX. KIWD will gust up to 26 to 28 kts.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 326 PM EDT WED OCT 5 2022
Light winds of 20 knots or less continue across Lake Superior until
late tonight, when a strong cold front drops down from northern
Ontario. Expect winds to quickly increase behind the cold front late
Wednesday night into Thursday, with northerly gales of 35 to 40
knots seen across the lake by late Thursday morning. Expect north
winds to decrease Thursday night into the 20 to 25 knot range late
as building high pressure weakens the pressure gradient across the
area. However, northerly gales to 35 knots could persist into early
Thursday evening over the east half. Winds briefly diminish to 20
knots or less on Friday as they back west-northwest in the
afternoon. West winds then increase again to 20 to 30 knots Friday
night into Saturday as another low pressure system moves across
northern Ontario. Would not be surprised to see a few gale gusts to
35 knots off the tip of the Keweenaw Peninsula late Friday night
into early Saturday. Light winds of 20 knots or less eventually
return Saturday night into Monday.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Gale Warning from 8 AM to 5 PM EDT Thursday for LSZ162.
Gale Warning from 8 AM to 7 PM EDT Thursday for LSZ240>244-263-
264.
Gale Warning from 8 AM to 10 PM EDT Thursday for LSZ245-248>251-
265>267.
Lake Michigan...
None.
&&
$$
SHORT TERM...JTP
LONG TERM...EK
AVIATION...TDUD
MARINE...JTP
Area Forecast Discussion
National Weather Service Missoula MT
226 PM MDT Wed Oct 5 2022
.DISCUSSION...Above normal temperatures will continue through the
rest of the week. The ridge of high pressure will slowly retrograde
westward, allowing for easterly winds to develop across western
Montana overnight and Thursday. This will also allow for cooler
temperatures compared to the past couple days, but will remain
slightly above normal for this time of the year. The HRRR smoke
model is projecting areas of haze, particularly across west-
central Montana through Friday of this week.
Forecast ensemble members continue showing an increasing
likelihood for a wet and colder weather pattern arriving Tuesday
and Wednesday next week, as a closed mid-level low pressure
traverses the intermountain west. Currently there is around a 70%
chance for this pattern to occur. Where the uncertainty remains,
are the details in how much rain occurs, and how low the
snowlevels ultimately get. As it stands now, there is about a 30%
chance that the high valleys along the Continental Divide will
receive up to an inch of snow by Wednesday morning. There could
even be a few snow flakes falling in the valleys across the
Flathead, south into Missoula.
As the system exits the region Wednesday, a colder Canadian air-
mass will settle in over the region. This will allow for the
potential of the first widespread frost/freeze in the valleys of
western Montana and north-central Idaho. Currently, there is a 50%
chance for the valleys of western Montana to wake up to lows in
the mid 20s Wednesday, Thursday and Friday mornings. There is
also a 32% chance for areas in the vicinity of Grangeville and
Pierce to lower to around 32F degrees. Make plans to protect those
sensitive plants and vegetation.
Long range forecast models indicate another ridge of high pressure
arriving by next weekend, allowing for normal temperatures and
drier conditions to return.
&&
.AVIATION...Patchy fog is again expected to develop by morning
across the Northern Rockies, with VCFG likely for KGPI and KMSO
through 06/1500Z. An easterly gradient will develop overnight,
producing a light easterly breeze. This will keep most of the fog
at bay, and will likely be confined to local bodies of water.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...None.
&&
$$