Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/23/22
Area Forecast Discussion
National Weather Service Denver/Boulder CO
859 PM MDT Fri Apr 22 2022
.UPDATE...
Issued at 859 PM MDT Fri Apr 22 2022
By 845 PM, the cold front has swept across all but the furthest
eastern zones, thus the RFW will be allowed to expire with RH
increasing quickly to 20-30 percent within an hour of FROPA in
most areas. In addition, the winds behind the front at much weaker
than what we saw into the early evening hours, so we have opted
to cancel the HWW a couple hours early though winds may still
gust to 40 mph for several more hours, particularly near the
foothills and across the far eastern plains. Winds will continue
to weaken all areas other than the higher mountains and foothills
above 8,000 ft. Latest CAMs show 50-60 kts cross barrier flow above
ridgetop tomorrow morning into midday. There is no stable layer
so that will limit mountain wave development, though there is a
critical layer (winds decrease quite a bit with heigh) above 500
mb which would support any mountain wave that develops. There is
also tremendous subsidence overhead as the trough swings across NE
Wyoming Saturday morning. This is a tricky forecast for winds
across the east slopes but believe the strongest winds will be
confined to the eastern foothills and not spread out below 6,000
ft elevation, though the favored wind corridor along CO-93 could
see gusts over 60 mph in the morning from 8 AM to Noon. The HRRR
is showing 80 mph gusts across the higher elevations of Boulder
County mid-morning tomorrow between 7-11 AM. The duration is
short and the areal coverage not great, thus for now have opted
not to hoist a High Wind Warning. The updated forecast reflects
this. Tomorrow afternoon with mixing and continued subsidence, a
bora-like event with strong NW winds and cold advection will make
it a windy afternoon across the entire area. Expect the strongest
gusts across the northern mountains and along the Wyoming border
across the northeast CO plains, where gusts in the 40-50 mph range
are expected. Gusts 30-40 mph are expected just about everywhere
else across the plains, Palmer Divide, and mountain valleys.
Two other slight adjustments were made based on the latest CAMs
and the fact that significant subsidence is expected. We removed
PoPs (they were very low to begin with) across most of the plains
other than along the WY border. Just too much downslope and
subsidence despite a little instability. We also dropped high
temps a couple degrees based on the latest guidance and the fact
that the cold advection on the backside of the trough, plus
convective cloud cover in the cold air would keep temps a little
cooler than originally expected. Highs across the plains should
still be upper 50s to around 60, with 30s in the mountain valleys.
Finally...there is some low-level moisture that worked back into
Sedgwick and Phillips counties. A few thunderstorms with strong
winds and marginally severe hail are possible between 10 PM and
midnight, but the window is narrow along the cold front and the
overall chances of any convection firing is probably less than 20
percent.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 301 PM MDT Fri Apr 22 2022
...EXTREMELY CRITICAL FIRE WEATHER CONDITIONS CONTINUE THIS
AFTERNOON...
Forecast grids are in good shape this afternoon. The stronger
winds have been a little slower to arrive than forecast, though
surface obs in the past hour indicate several gusts above 40-45
mph in the plains, along with a few gusts above 60 mph at Limon
and the Cheesman RAWS. Guidance is insistent on stronger gusts
later this afternoon and evening as the 700mb flow increases to
45-55kt over the plains. Deep mixing... perhaps as high as 400mb
or so... should make it easy for at least some of this wind to
translate down to the surface over the next several hours. With
how dry and windy it already is, I see no reason to modify the
ongoing RFW or HWW products right now. We`ve been fairly lucky so
far this afternoon, but it cannot be stressed enough that
extremely critical fire conditions will be present across the
Foothills and all of the lower elevations through at least sunset.
The dryline should retreat west near the eastern CO border this
evening and overnight, and an isolated storm or two could fire
along this boundary in the evening. SPC`s marginal/slight risk
over our far northeast corner is highly conditional but a couple
of storms can`t be ruled out. Any storm that`s able to survive and
take advantage of the warm/moist sector environment could produce
a strong wind gust or large hail, but the overall chances of
storms in our forecast area is fairly low. Additional showers will
also be possible over the far northeast as moisture wraps around
our departing surface low overnight.
The more difficult aspect of the forecast comes tonight and
tomorrow. It`s looking increasingly likely that stronger winds
develop across the Front Range Foothills tonight, with two bursts
of strong gusts likely. The first comes this evening as the upper
trough axis crosses the area a couple of hours after sunset.
Ridgetop winds are near 50-60kt, and it wouldn`t take much to get
a couple of 60-70mph gusts in the higher elevations as this moves
through. The more intense period of mountain wave winds comes late
tonight through Saturday morning. Ridgetop winds are again near
60kt and well aligned out of the west, with a clearly defined
critical layer located near 500-550mb. There should also be strong
mid-level subsidence that should contribute to some amplification
of the wave, and a few 75mph gusts are possible especially above
7000 feet in the morning.
Cooler temperatures will return for Saturday, though strong
synoptic scale winds should accompany the cool weather. The
strongest winds will be along the northern border from the
Cheyenne Ridge and into Sedgwick/Phillips county, where 700mb flow
is again near 50kt. With very strong subsidence through the
boundary layer, we should see at least a few strong gusts make it
to the surface there. Winds will be a touch weaker for the urban
corridor and eastern plains, but the wind will certainly still be
noticeable. A few showers will also be possible though
precipitation amounts are forecast to be very light.
Winter weather will also be a concern along and west of the
divide. Moisture will continue to slowly increase this afternoon
with snow showers developing after about 6pm, with more widespread
snow between midnight and noon. Accumulations will largely be
limited to areas above 9000 feet, though an inch or two is still
possible over the mountain parks. Will continue the Winter Weather
Advisories as planned with no major changes there.
.LONG TERM...(Saturday night through Friday)
Issued at 301 PM MDT Fri Apr 22 2022
We`ll have drying with decreasing winds on Saturday night. Skies
should clear pretty well over the plains, though there may still
be some clouds near the northern border. The mountains will keep
the clouds, but the snow will be diminishing. There will still be
strong winds over the higher mountains, but the winds on the
plains should drop off fairly quickly after sunset.
Models continue to trend a little stronger/slower/colder with the
baggy south end of another shortwave that moves across Sunday
afternoon through Monday morning. This should generate clouds and
probably has enough of a combination of weak lift, moisture, and
instability for a good crop of showers over the mountains in the
afternoon and evening. It`s hard to tell how much of this could
get east of the mountains. There`s a period of nice upslope winds,
but the low levels also look pretty dry. Some low PoPs mainly
south of Denver seem appropriate. It could be cool enough in the
late evening for rain to change to snow as it is ending in areas
south of Denver, but any accumulation would be minimal and limited
to grassy areas. The mountain areas should mostly have light snow,
but there could be some heavier showers at the peak in the late
afternoon and evening. It appears this will be focused from the
I-70 corridor in the late afternoon southeast across Park county
in the evening.
Not much change to the forecast for next week. We`ll still be cool
on Monday behind the shortwave, but it should clear pretty well.
Then it will be dry and warmer through the middle of the week.
Solutions vary about when and if it will be breezy, but the threat
of strong winds looks low until ahead of the trough late in the
week. There gets to be a bigger model spread for Thursday and
Friday, anywhere from hot and windy, to a low key severe weather
setup with weak upslope flow, to cooling into the 60s behind a
cold front. The one point of agreement is that the threat of
significant precipitation remains north of us.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 540 PM MDT Fri Apr 22 2022
Winds remain strong as expected this evening. For the most part
the strongest winds should have already occurred at the terminals,
with gradually decreasing winds expecting overnight. There will be
a wind shift to just south of due west around 8 PM (maybe 7 PM at
BJC). Expect the speeds to be lower with the west winds but still
gusting 25-30 kt until about midnight. Then after midnight the
winds at APA and DEN should be SW at 10-15 kts until 8 or 9 AM.
BJC could be a different story. Behind the cold front there is a
stable layer and critical layer of wind shear at 15 kft AGL, which
could generate a decent mountain wave. The winds from the mountain
wave may get as far east as BJC (but no further), which could
result in gusts over 40, maybe 50 kts between 3 AM and 10 AM. We
are keeping it out of the TAF for right now but will keep an eye
on the possibility. There will continue to be some BLDU at APA
and especially DEN this evening, but with the west wind shift
around 8 PM the dust should stay away after that.
On Saturday northwest winds will be the norm, and they will be
strong with sustained 20-25 kts and gusts to near 40 kts after 10
AM. By Saturday evening winds should slowly veer to the north and
weaken to around 15 kts with gusts over 25 kts. ILS conditions
are possible with scattered cumulus decks at around 050, maybe as
much as BKN by mid afternoon.
&&
.FIRE WEATHER...
Issued at 301 PM MDT Fri Apr 22 2022
Essentially every RAWS and ASOS station within the current Red
Flag Warning is experiencing critical fire weather conditions.
Several sites are now reporting humidities between 5 and 8% with
wind gusts continuing to slowly ramp up. Extremely critical
conditions are forecast to continue through sunset this evening
with humidities remaining below 10% for at least a few more hours.
At least a slight improvement in moisture is expected this evening
as a "cool front" shifts winds more to the west while humidities
climb into the upper teens across the Foothills and Plains.
Overnight humidity recovery is a concern across the Foothills and
urban corridor, especially given the lingering high wind threat
overnight into tomorrow. Saturday`s conditions look a little
better. Winds will be northwesterly and still pretty strong, but
humidities will settle near 20% in the afternoon. Did ponder the
idea of additional Red Flag Warnings for a few spots but
ultimately will leave it be for now.
There will still be some wind on Sunday, but temperatures will be
cool. Monday will have lighter winds. There will be a warming and
drying trend through midweek. It will be breezy at times, so
conditions could be near Red Flag criteria, but strong winds are
not expected in this period. There is a chance of stronger winds
on Thursday or Friday, but there is much uncertainty about the
weather pattern on those days as another system approaches.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until midnight MDT Saturday night for
COZ031-033-034.
&&
$$
UPDATE...Schlatter
SHORT TERM...Hiris
LONG TERM...Gimmestad
AVIATION...Schlatter
FIRE WEATHER...Gimmestad/Hiris
Area Forecast Discussion
National Weather Service Columbia SC
805 PM EDT Fri Apr 22 2022
.SYNOPSIS...
High pressure will dominate the forecast period through
early next week with steadily warming temperatures and dry
weather expected each day. Highs will be in the 80s late this
weekend and early next week. A cold front will bring scattered
showers and thunderstorms to the Southeast on Tuesday with dry
weather following for the remainder of the week.
&&
.NEAR TERM /UNTIL 7 AM SATURDAY MORNING/...
Little change in the pattern with high pressure northeast of
the area. Winds remain light to calm through the night. Skies
mostly clear. Overnight lows mainly in the middle 50s. Can not
rule out patchy fog formation...especially in the southeast
Midlands and CSRA as suggested by Lamp and HRRR guidance.
&&
.SHORT TERM /7 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
Dry, warm weather will continue through the short term. Other
than patchy morning fog, benign weather is expected.
Mid and upper level ridging will be firmly in place over the
weekend. 500 hPa heights are expected to be in the 90th-95th
percentile per NAEFS. This pattern supports dry weather and
temperatures above normal values. Highs each day will be in the
low to mid 80s with overnight lows in the mid to upper 50s.
Surface high pressure will direct persistent southeasterly flow
over the region. This will lead to increasing shallow moisture
and could promote areas of fog or low clouds each morning.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
The pattern of warm, dry weather will continue into Monday which
will likely be the warmest day of the forecast. Expect highs
mainly in the mid 80s but a few areas could break into the upper
80s. As the upper ridge axis shifts offshore Tuesday, a cold
front will move into the Southeast as the associated upper
trough lifts north of the ridge. Models indicate weak moisture
advection ahead of the front on Tuesday. The airmass should
destabilize during the afternoon and support convective
development ahead of and along the front. With only weak
moisture advection and limited upper level support we expect
showers and thunderstorms to be scattered. At this point it
appears that instability will be weak and updraft strength may
be hindered as the front moves eastward and encounters the
upper ridging. Severe weather appears unlikely for Tuesday in
central SC and the CSRA. The cold front is expected to pass
through the forecast area by Wednesday, ushering in
temperatures near or slightly below normal for the end of the
week. Precip during the remainder of the long term is unlikely
given the dry air behind the front.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
VFR expected through the TAF period at CAE, CUB, and DNL;
morning fog possible at OGB and AGS.
Light/calm winds expected overnight with clear skies through
early morning. Some typical morning issues expected AGS with
low river/ground fog. A bank of fog is likely to develop along
the coastal plain and may reach OGB around sunrise. Included
some tempo groups to account for this but confidence is fairly
low. Any remaining fog will burn off after sunrise, making way
for another day with scattered low top cu and east-
southeasterly winds, 5-7 knots, for all terminals.
EXTENDED AVIATION OUTLOOK...Slowly increasing low level
moisture will bring a chance for morning fog each day but
otherwise no restrictions expected through Tuesday. A cold
front will bring a chance of rain and restrictions Tuesday into
Wednesday.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
AREA FORECAST DISCUSSION
National Weather Service Sioux Falls SD
1059 PM CDT Fri Apr 22 2022
.SHORT TERM...(This Evening through Saturday)
Issued at 353 PM CDT Fri Apr 22 2022
A very busy 24 h is on hand across the forecast area. Several
hazards will be possible in this time.
1. There is the potential for severe thunderstorms both tonight
and again from late Saturday morning through the afternoon.
2. Strong winds are expected overnight in the Missouri Valley
tonight and across the entire region much of Saturday.
3. Very strong winds combined with low relative humidity may
produce hazardous fire weather conditions Saturday afternoon in
portions of the Missouri and Big Sioux Valleys.
Severe weather tonight: A warm front extends from from south
central South Dakota into west central Iowa. Sunny skies exists
south of the warm front and even 30-50 miles north of the front.
Temperatures have warmed to near 90 along the SD/NE border. While
closer to the convective temperature, the SBCIN remains from 25 to
50 J/kg. Model soundings show that immediately north of the front
the atmosphere rapidly becomes more stable with SBCIN < -150 J/kg
north of I-90 even with temperatures into the lower 80s. So there
remains questions if storms will be able to develop near the warm
front late this afternoon and evening. Many CAMs, outside the
FV3, have been reluctant to develop convection this evening with
the strong cap in place. Earlier runs of the HRRR also limited
convection but the 18Z HRRR now develops isolated cells north of
the front. So confidence is low (< 30%) that convection will even
initiate along the front this evening. If storms do develop, they
are likely to be multicellular if south of I-90 where bulk shear
is 25-30 kts. However, with MLCAPE of 1000-1250 J/kg and DCAPE >
1500 J/kg the greatest threat would be wind gusts to 70 mph. A few
storms could also produce quarter to half dollar size hail. North
of the boundary, deep layer shear improves to 40-50 kts north of
I-90. As noted, there is a strong cap in place for surface
parcels. But if elevated storms are able to develop, they could
become supercellular with the potential for hail up to golf ball
size and wind gusts to 60 mph. A tornado cannot be completely
ruled out if the storm interacts with the surface boundary but
the probability is very low.
After dark, additional storms that form over south central
Nebraska could move north across the area. Shear decreases to < 30
kts across the area so storms would be multicellular. And with the
stabilizing boundary layer the threat of wind gusts would lessen.
However, with very strong winds aloft, an isolated gust to 60 mph
or quarter to half dollar hail could occur. The severe threat
should decrease after 06Z.
Severe weather Saturday: A dry line will move east of the Missouri
River early Saturday morning. The dry line will move to I29 late
Saturday morning and into Minnesota and Iowa by early afternoon.
Ahead of the dry line temperatures will warm into the upper 60s to
lower 70s with dew points in the upper 50s to lower 60s. While
this results in MLCAPES around 1000 J/kg, very warm air around 850
mb will maintain a strong cap ahead of the line. So parcels being
lifted along the dry line are going to struggle to reach the LFC
especially in the late morning and early afternoon. The other
limiting factor is the very strong low level shear. With updrafts
likely to be weakened by trying to break the cap, these updrafts
may initially be disrupted by the strong shear. The cap may
weaken as the dry line approaches Hwy 71 in MN/IA around 3pm and
this is the best chance for thunderstorms in our area. If storms
are able to develop, 0-6 km shear of 40-50 kts may help any
discrete cells to develop supercell characteristics. Another
concern is that the 0-1 km shear will be 20-30 kts. That means
there is a tornado threat with any discrete cells that can persist
for an hour or more. At this time, this threat appears low as
once storms begin to form, they should quickly develop into a
line. Therefore the primary severe weather threat will be winds of
70 mph and half dollar size hail.
Winds tonight through Saturday; A very strong low level jet will
develop overnight and persist through Saturday. Wind speeds within
the LLJ will be from 60-70 kts. Even at 925 mph winds will be
40-50 kts overnight. While a nocturnal inversion will develop
after sunset, strong winds will keep temperatures low to mid 60s
in the Missouri Valley so this inversion will not be very strong.
The surface pressure gradient itself will produce sustained winds
around 30 mph later tonight. In addition, gusts of 45-55 mph are
possible. It is not impossible that a few gusts to 60 mph could
occur especially if showers are able to develop and bring the
stronger winds to the surface. At this time, the probability is
low (30%) so no high wind warning has been issued.
On Saturday, the dry line will move into the area. In central
South Dakota, there will be little distance between the dry line
and cold front so winds will quickly turn to the northwest and may
gust to 45-50 mph. However as the day progresses the dry line will
accelerate east. Behind the dry line winds will turn southwest.
Several CAMs show winds around 50 kts at the top of the mixed
layer. So we are expecting wind gusts to 55 mph after the dry
line moves through. As with tonight, the potential exists for
gusts over 60 mph especially between the james River and I-29 as
this area will between the dry line and cold front during peak
heating. A high wind warning was considered for this area but
confidence remains less than 50% that these gusts will occur so we
did not issue one at this time. However, persons driving high
profile vehicles should be aware of wind conditions before setting
out tomorrow. Winds will slowly decrease toward sunset. These
winds will also produce very high to extreme fire weather
conditions. this will be discussed below.
For most areas, rainfall is going to be limited with this system.
While local rainfall amounts of 0.5" is possible in thunderstorm,
many places will see little or no rain tonight or Saturday. As for
temperatures, lows tonight will be in the 60s. Temperatures west
of the James will see highs in the 60s early in the morning with
falling temperatures much of the day. Elsewhere 70s to lower 80s
are expected.
.LONG TERM...(Saturday Night through Friday)
Issued at 353 PM CDT Fri Apr 22 2022
Any convection in southwestern Minnesota and northwestern Iowa
will move east prior to sunset. Light rain showers may move into
areas west of the James River overnight Saturday. The chance for
rain is 20-40% and amounts would be less than a tenth of an inch.
Winds will remain fairly strong - especially west of the James
River where gusts will again approach 45 mph. Winds will be a
little lighter east of the James with gusts to 40 mph possible.
Unseasonably cold air will move rapidly east during the late
afternoon and evening with lows falling into the 30s.
Sunday will be a cold, cloudy and windy day. It is again possible
winds will be over 30 mph with gusts over 45 mph. However enough
uncertainty exists that no wind advisory has been issued at this
time. Temperatures will struggle warm much during the day with
highs from the mid 40s along Hwy 14 to the mid 50s along Hwy 20.
Quieter weather is expected next week. Temperatures will warm to
normal reading in the 60s to lower 70s by mid week. The next
chance for rain will not be until late in the week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1051 PM CDT Fri Apr 22 2022
VCTS remains possible through about 10z at KHON, as TS pass off to
the north and west of the terminal. Elsewhere, periodic shower and
thunderstorm chances continue through the period, which could lead
to MVFR ceilings and visibilities. Otherwise expect VFR conditions
to prevail, although could see some low end VFR stratus at times.
Very strong winds continue through the period with a strong low
level jet, with southerly winds gusting to 45 knots overnight for
most of the area. Have added some LLWS for a few hours overnight
for KHON and KFSD for the direction difference. Winds begin to
shift westerly toward the end of the period Saturday evening.
&&
.FIRE WEATHER...
Issued at 353 PM CDT Fri Apr 22 2022
Critical fire weather conditions are possible tomorrow afternoon
in portions of the Missouri and Big Sioux Valleys. Once the dry
line moves through southwest winds gusting over 50 mph can be
expected. In addition, temperatures will quickly warm into the mid
to upper 70s with 80 degrees possible near the Missouri River. As
temperatures rise, dew points will fall into the 40s producing
afternoon relative humidities of 20-25%. There is still some
uncertainty how long these critical fire weather conditions will
persist. If the cold front moves faster, then conditions may only
last an hour or two. However, if, as expected, the cold front does
not reach I-29 until late afternoon or early evening, then
critical fire weather conditions will persist for several hours
Saturday afternoon. Additionally, forecast conditions with winds
gusting to 55 mph and of 20-25% represent the most likely
conditions. A potential worst case scenario shown by the WRF-ARW
has wind gusts to 60 mph with minimum RH less than 20% much of
the afternoon.
With the threat for critical fire weather conditions, a fire
weather watch has been issued for portions of the Big Sioux and
Missouri Valleys where the worst conditions are most likely. This
includes Sioux Falls, Sioux City, and Yankton.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...High Wind Warning until 5 AM CDT Saturday for SDZ050-063-068>070.
Fire Weather Watch from Saturday afternoon through Saturday
evening for SDZ062-066-067-069>071.
Wind Advisory from 9 AM to 7 PM CDT Saturday for SDZ038>040-050-
052>071.
Wind Advisory until 5 AM CDT Saturday for SDZ052-053-057>060-
064>066.
MN...Wind Advisory from 9 AM to 7 PM CDT Saturday for MNZ071-072-080-
081-089-090-097-098.
IA...Fire Weather Watch from Saturday afternoon through Saturday
evening for IAZ001-012-020-031.
Wind Advisory from 9 AM to 7 PM CDT Saturday for IAZ001>003-
012>014-020>022-031-032.
NE...High Wind Warning until 5 AM CDT Saturday for NEZ013-014.
Fire Weather Watch from Saturday afternoon through Saturday
evening for NEZ013-014.
Wind Advisory from 9 AM to 7 PM CDT Saturday for NEZ013-014.
&&
$$
SHORT TERM...Schumacher
LONG TERM...Schumacher
AVIATION...SG
FIRE WEATHER...Schumacher
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
1005 PM CDT Fri Apr 22 2022
.UPDATE...
Issued at 1003 PM CDT Fri Apr 22 2022
The forecast gets a temperature dewpoint update for warmer more
moist conditions using the RAP and HRRR models.
UPDATE Issued at 920 PM CDT Fri Apr 22 2022
High wind gusts have been reported as far west as Scottsbluff this
evening. A High Wind Warning is now in effect for all of western
and ncntl Nebraska until 6 am CDT...the time a Pacific cold front exit
ncntl Nebraska. The passage of the front will mark the end of
this high wind event.
UPDATE Issued at 903 PM CDT Fri Apr 22 2022
A thunderstorm across Blaine county started a grass fire this
evening. The Red Flag Warning for western and ncntl Nebraska has
been extended in time until 6 am CDT...the approximate time the
thunderstorms will exit the region.
UPDATE Issued at 737 PM CDT Fri Apr 22 2022
A forecast update is in place for widespread blowing dust across
much of wrn and ncntl Nebraska.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 344 PM CDT Fri Apr 22 2022
Fire weather concerns continue Saturday as strong northwest winds
develop along with dry air. The concern will be for areas especially
south of I-80. A fire weather section below has more detailed
information regarding the fire potential.
Potent upper trough is evident on WV imagery moving this afternoon
moving across Utah. Surface low pressure is in the process of
rapidly deepening across the Nebraska Panhandle ahead of this
feature. This is resulting in a tight east-west pressure gradient
across the Plains. Strong southerly low-level flow is helping
transport quality Gulf moisture/humidity northward into the region.
A dry line has become established across western Kansas into western
Nebraska with a warm front located near the NE/SD border. An EML has
overspread the area and resulting in a capping inversion across the
region. CAMS are reflecting this and do not give much support of
development near the warm front late this afternoon, but continue to
focus more on the dry line across western Kansas for at least
isolated convective development around 23Z-01Z timeframe. By early
evening, soundings are very favorable for supercells along the HWY
83 corridor and vicinity as winds in the low-levels begin to back
slightly to the southeast. This coincides with a westward retreating
dry line with a surge of lower 60s dew point into western Nebraska.
The isolated convection in western Kansas could grow upscale into a
couple of supercells as it travels northeastward into southwest and
central Nebraska during the evening.
The other focus will be along the surging cold front that
essentially meets the westward retreating dry line mid-evening
across west central Nebraska. This is about the time that the best
forcing arrives, and should see the rapid development of a squall
line take shape along the cold front/dry line. This line is then
expected to advance quickly eastward across the area overnight. This
line will be pushing into a favorable environment with a strong
southerly LLJ, etc. It appears that the line could remain near-
surface based due to the rapid increasing low-level moisture and
strong southerly winds and mixing through the boundary layer. This
scenario could lead to the potential for an isolated tornado along
the leading edge of the line. Regardless, strong winds will be
likely as 55-65 kt low level jet could lead to gusts nearing 60 mph
(even well ahead of the line) as the strong winds mix to the
surface.
The upper low will move northeast across South Dakota on Saturday.
Gusty northwest winds develop Saturday through Saturday night and
then begin to decrease on Sunday. Bufkit sounding profile data
indicates the potential for 55 mph gusts. Threat for light wrap-
around rain or snow, mostly across northwest Nebraska. We`ll have to
watch the higher elevation of the Pine Ridge where 1-3" of wet snow
could accumulate.
.LONG TERM...(Sunday through Friday)
Issued at 344 PM CDT Fri Apr 22 2022
Upper level ridging looks to dominate the weather for much of the
upcoming week. Temperatures will be above normal by the middle of
the week. The airmass will be dry the first half of the week. Some
wind is expected during this time which could lead to potentially
more fire weather concerns. It doesn`t appear though that winds will
be near as strong this coming week as they have been the last
several. Upper troughing takes shape across the western CONUS late
in the week. This should allow for some return flow of Gulf moisture
through the Plains by late in the week, possibly leading to at least
a slight chance for rainfall/thunderstorms.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 652 PM CDT Fri Apr 22 2022
There will be a variety of weather impacts to aviation through the
forecast period. Strong winds have lofted blowing dust into the air
in areas of southwest Nebraska, therefore included a lower ceiling
at KLBF. A line of thunderstorms is currently moving through areas
of north central Nebraska which may result in lower chillings,
reduced visibility, and erratic winds near the storms. A surface
front will move through the forecast area later in the evening
causing winds to shift to the west and bring around 60 knots of
LLWS. The frontal passage will bring the possibility for another
round of thunderstorms, with similar impacts to the first round.
This is expected to impact KLBF between 04 and 07. There is a
lesser threat for thunderstorms at KVTN. Gusty winds will persist
through the forecast period, between 30 and 50 knots. Rain and
light snow will last into tomorrow morning in northern Nebraska.
&&
.FIRE WEATHER...
Issued at 344 PM CDT Fri Apr 22 2022
Critical fire weather conditions will continue across the area
through mid evening as strong southerly winds will increase into
the evening hours. By mid evening, some wind gusts may top 60 MPH.
Any fire starts will quickly spread and will be difficult to
control. Later this evening, a squall line is expected to develop
in the vicinity of highway 61. This line of storms will track
quickly east into the overnight hours. Moisture will be limited
with this line of storms, so there may be dry lightning strikes
this evening and overnight. Behind the squall line, gusty westerly
winds are expected overnight and some gusts may reach 50 MPH
overnight. Windy conditions will continue into Saturday with
elevated to near critical fire weather conditions.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
High Wind Warning until 6 AM CDT /5 AM MDT/ Saturday for
NEZ004>010-022>029-035>038-056>059-069>071-094.
Red Flag Warning until 6 AM CDT /5 AM MDT/ Saturday for NEZ204-
206-208>210-219.
&&
$$
UPDATE...CDC
SHORT TERM...Taylor
LONG TERM...Taylor
AVIATION...Meltzer
FIRE WEATHER...Buttler
Area Forecast Discussion
National Weather Service New Orleans LA
642 PM CDT Fri Apr 22 2022
...EVENING UPDATE...
No major changes needed to the evening update going into tonight
and into parts of tomorrow as trends remain on track. Took a
closer look at the potential for patchy fog, which NBM
probabilities look lower compared to yesterday. Regardless, did
mention light fog for a few hours across Pike and Walthall
counties around daybreak which widespread dense fog not
anticipated ATTM. Only other adjustment was pertaining to lows,
with a lower bias applied to typical drainage locations where
winds could lower enough to calm, or nearly calm for a few hours
around sunrise.
Otherwise, tomorrow is looking nice and pleasant overall with
breezy southeasterly winds and are-developing Cu field mid/late AM
into the afternoon hours. Interesting seeing the synoptic hour
extended runs of the HRRR try to depict an isolated shower or two
tomorrow primarily across central and western areas, which leaned
NBM PoPs nearing 10% or so in this region. Closer look into this
by comparing KBTR forecast soundings valid 18Z earlier today to
forecast soundings valid for 18Z tomorrow shows a some change in
the state of the atmosphere, namely a slight increase in deep-
moist ascent/WAA in the low-levels, helping to ascend the
subsidence inversion by around 80-100mb and shrinking it some.
This reveals some positive buoyancy between the base of the
inversion and LCL during the day tomorrow. Curious given the sfc
wind field if any isolated localized convergent axis/boundary can
help pop a light shower or two. But given the low impact, did not
make any targets of opportunity against blended guidance,
especially as any stronger growth in development would likely not
happen given the warm thermal profile aloft and lack of large-
scale ascent. So all in all, a passing light shower or two can`t
be ruled out tomorrow but will be primarily dry and warm. KLG
&&
PREV DISCUSSION... /issued 328 PM CDT Fri Apr 22 2022/
SYNOPSIS...
Upper ridging this afternoon from the Florida Panhandle northward
into the Great Lakes. A deep upper trough was noted over the
Intermountain West. At the surface, high pressure over eastern
Canada extended southward into the Carolinas, then westward into
our area. Low pressure was developing over Colorado.
Locally, southeasterly breezes continued to bring a layer of
moisture into the area that produces scattered to broken flat
cumulus around 4000 feet. Mid-afternoon temperatures were
generally in the lower and middle 80s, with dew points in the 60s.
SHORT TERM (through Monday)...
Will continue Coastal Flood Advisory through Sunday as previously
depicted. This will continue to be a minor event, but once we get
past Sunday, astronomical tide ranges decrease, and the onshore
wind flow will relax, so we don`t anticipate it going beyond
Sunday.
Little change in the forecast surface pattern through Sunday, with
the exception that there may be a brief period Sunday afternoon
when the atmosphere west of Interstate 55 may destabilize enough
for a few showers or possibly a thunderstorm or two. If anything
develops, it`ll likely dissipate with the loss of surface heating.
The upper trough over the west will gradually lift toward the
Great Lakes tomorrow and Sunday, forcing the ridge off the Florida
east coast. It`ll take a second shortwave rotating through the
base of that trough to push the associated cold front into the
area Monday and Monday night. Rain chances will increase Monday
afternoon, but generally remain in the chance range.
Not a lot of difference in temperature guidance through Monday,
and will generally remain around the middle ground of the NBM
envelope. This would generally be in the mid 80s for highs (cooler
on MS coast) and lows in the 60s. 35
LONG TERM (Monday night and beyond)...
Upper trough eventually wears down the ridge enough Monday night
and Tuesday to allow the cold front to move across the area and
through the coastal waters. Best dynamics and low level moisture
convergence will be to the north of the area, but will still need
to carry chance to likely PoPs in the forecast for Monday night
and Tuesday. Doesn`t appear to be a heavy rain or severe weather
threat with this system at present, and it`ll be nice to go
through a week without severe weather for seemingly the first time
in about 2 months. As upper and surface ridging shifts eastward
across the area during the second half of the week, dry weather is
anticipated from Tuesday night through Friday.
Monday night lows will be dictated by the timing of cold frontal
passage. The cool down behind the front will be most noticeable
due to considerably lower dew points allowing for cooler overnight
lows. Even then, guidance spreads aren`t all that large. As has
been the case with the drier airmasses recently, would favor the
lower end of the guidance on overnight lows and the upper end on
daytime highs. 35
AVIATION (00Z TAF DISCUSSION)...
Latest VIS satellite/obs continue to indicate SCT Cu field
diminishing, with primarily SKC and VFR conditions expected to
prevail into tonight through early Saturday. Some potential for
light fog formation from MCB to BTR, but probabilities remain
low. Have introduced just a quick drop in VIS for MCB around
daybreak, but impacts should be limited to only periodic lower
flight categories. Otherwise, Cu field redevelops mid/late morning
tomorrow with prevailing SE winds and VFR conditions through the
rest of the TAF period. KLG
MARINE...
Will continue the Small Craft Exercise Caution headlines overnight
for the open waters as well as Breton and Chandeleur Sounds.
Observations on Lake Pontchartrain and Mississippi Sound have
shown the winds dropping off to around 10 knots after sunset the
last couple nights, and guidance indicates this will occur again
tonight. Little change in the surface pressure pattern for the
next couple of days, so will anticipate similar conditions to
continue through at least Sunday. Conditions may relax for a while
on Monday as front approaches, with recent guidance indicating it
may take a good bit of the day Tuesday to get the front through
the coastal waters. Northerly winds behind the front will probably
necessitate Small Craft Advisories Tuesday night. 35
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 58 85 63 84 / 0 0 0 20
BTR 61 85 65 85 / 0 10 0 30
ASD 60 84 64 84 / 0 0 0 10
MSY 66 84 69 84 / 0 10 0 20
GPT 62 80 66 81 / 0 0 0 0
PQL 58 81 63 81 / 0 0 0 0
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Coastal Flood Advisory until 7 PM CDT Sunday for LAZ064-069-070-
076-078.
GM...None.
MS...Coastal Flood Advisory until 7 PM CDT Sunday for MSZ080>082.
GM...None.
&&
$$
Area Forecast Discussion
National Weather Service Lubbock TX
700 PM CDT Fri Apr 22 2022
.AVIATION...
Isolated thunderstorm development has been occurring west of I-27
early this evening. These thunderstorms have been struggling to
develop so far however thunderstorm development remains possible
through roughly 10 pm. Confidence in this activity impacting
KLBB/KPVW remain too low to include a mention at this time.
Outside of convection, southerly winds will remain gusty through
much of the overnight. These strong winds are leading to blowing
dust reducing the visibility at both KLBB and KPVW and this is
expected to continue after sunset. Winds will gradually diminish
early Saturday morning but then become breezy once again late
Saturday morning.
&&
.PREV DISCUSSION... /issued 218 PM CDT Fri Apr 22 2022/
SHORT TERM...
The main focus for this afternoon and evening will be the
possibility for strong to severe thunderstorms. Clouds have been
slow to clear the region resulting in temperatures just now reaching
the 80 degree mark. Temperatures should continue to slowly rise
through the afternoon as additional sunshine is attained. Cooler
temps have kept a fairly stout capping inversion overhead with 15Z
LBB AMDAR sounding showing a +6C inversion and a convective temp of
84F. Evidence of the still in place cap is evident on visible
satellite with low level cumulus present across much of the Caprock.
The CU field is most dense from Floyd county southwestward to Lea
county, New Mexico where surface moisture is abundant and surface
flow is somewhat convergent. Currently convective models are in a
general consensus that convective initiation should occur in this
general vicinity northward to the western Texas Panhandle as a
dryline works its way eastward from eastern New Mexico. Overall
upper level support for storm development appears to be marginal at
best which explains why models keep convective coverage isolated and
limited, if the model has convection at all. For now the forecast
will reflect low end storm chances. This will be due to storms
relying mostly on low level initiation which, like with the upper
levels, is lacking enthusiasm. If a storm is able to develop it will
have plenty of CAPE to work with as SPC RAP Mesoanalysis continues
to show MLCAPE between 2000-2500 j/Kg, 0-6 km shear around 50+
knots, and modestly steep lapse rates. The main threats will be wind
gusts up to 70 mph and large hail up to baseball size. The overall
lack of backed surface winds and weak 0-1 km shear will limit the
overall tornado threat, but it will not be null as dewpoints remain
near 60F. Storms will move quickly to the northeast with the overall
convective threat decreasing significantly after sunset.
The combination of a developing surface low over southeastern
Colorado and 40-50 knot LLJ will allow for a windy start to the
night with solid advisory level winds expected. GFS MOS is the most
bullish with sustained winds of 46 mph forecasted at LBB between 7
PM and 1 AM. NAM MOS keeps winds slightly lower at 40 mph. The wind
forecast has been increased accordingly for this evening to reflect
the potential for strong winds. The Wind Advisory will remain in
place through 1 AM tonight across the entire South Plains region.
The upper low currently over the Four Corners will push a Pacific
Front through the region late tomorrow morning into the afternoon.
Though still on the breezy side, winds will be lower tomorrow
afternoon than what is expected tonight (15-20 mph). Minimum RH
values will drop to near 10 percent area wide tomorrow afternoon
despite slightly cooler temps. This will result in elevated to
critical fire weather danger.
LONG TERM...
As the upper level trough spins off into the Northern Plains on
Saturday, it will send a cold front through the area late Saturday
through early Sunday. This will provide the area with several days
of cooler than seasonal average temperatures. This front is still
expected to stall out just to the south of the area after it moves
through on Sunday. Another short wave moving through the
central/southern Rockies will rotate around the larger scale trough
on Sunday. This will keep southwesterly flow aloft near the frontal
zone. Areas close to the front could see widespread heavy rainfall
which may affect portions of the southern Rolling Plains and
southern South Plains. The location of heavy rainfall will be highly
dependent on the position of the stalled out front. There will be a
strong demarcation between high and low precipitable water air. This
will last through the day Sunday into early Monday when a
reinforcing shot of surface ridging moves into the area.
Temperatures will be on the increase beginning mid-week with an
upper ridge moving overhead.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Saturday morning through Saturday
evening for TXZ021>044.
Wind Advisory until 1 AM CDT Saturday for TXZ021>044.
&&
$$
58/99/99
Area Forecast Discussion
National Weather Service Marquette MI
849 PM EDT Fri Apr 22 2022
.SHORT TERM...(Through early this evening)
Issued at 321 PM EDT FRI APR 22 2022
Low currently sitting in CO will inch its way northeastward, but
not significantly during this forecast period. Nonetheless, its
influence as a warm front approaches Upper Michigan will be felt
as today turns into tonight. Currently, the U.P. is sitting in
between a compact MCC crossing northern MN and a much larger MCC
spanning from IA through northern IL and into the lower Great
Lakes region. Some reflectivity returns are being picked up
locally on radar this afternoon, although how much of it is
reaching the surface remains questionable. As warm, moist air
continues to advect into the U.P., moistening the lower levels,
have continued to hold onto mentionable PoPs primarily along the
WI border. With some instability also inching closer to the MI
border by day`s end, do have very low-end thunder chances to
account for some possible rumbles. Highs are likely occurring
currently for most locations, although some spots downsloped from
the SErly winds could still climb another degree or so before the
afternoon comes to a close.
.LONG TERM...(Saturday night through Friday)
Issued at 422 PM EDT FRI APR 22 2022
Not much has changed in the last few forecasts as a warm front will
bring thunderstorms and above normal temperatures this weekend as a
sfc low pressure system slowly lifts from the Plains through
northern MN. As the low continues north into Ontario on Sunday, its
cold front will pass from west to east across the UP, bringing
temperatures back below normal...as well as a chance for some lake-
effect/enhanced snow showers on Tuesday. High pressure shifts over
the area on Wednesday, with southerly return flow bringing temps
back closer to normal to end the week.
The advertised warm front is progged to lift north across Upper
Michigan tonight, bringing the chance for showers and thunderstorms.
Currently, the warm front is across southern Wisconsin, where an
ongoing MCS this morning traversed along and through the front.
There is some uncertainty leading into tonight if this will affect
pcpn chances or not, but a strong LLJ is expected to bring strong
theta-e adv across the area. Latest RAP suggests 700-1000J/kg MUCAPE
will lift across Upper Michigan btwn 03-06Z along a 40kt LLJ. There
looks to be sufficient enough shear to bring the chance for some
hail tonight as well...at least initially as shear is progged to
decrease quickly behind the fropa. Widespread soaking rains don`t
appear likely with this fropa, but thunderstorms could produce a
quick 0.50+ inch of rain. This rain potential and the ongoing
snowmelt with rivers already remaining elevated could bring some
localized flooding across area rivers as well.
By tomorrow morning, thunderstorms across the area should already be
lifted north across Lake Superior leaving behind cloudy skies. Model
soundings suggest plenty of MUCAPE during the day Saturday, but
there is a strong stable layer above 800mb that won`t allow much to
get going. With abundant low-level moisture beneath this inversion,
should remain cloudy through the day and there could be some fog in
the morning, or even mist/drizzle in the upslope areas.
Cold front will pass over the UP on Sunday bringing another small
chance of some thunderstorms. Depending on the timing of the front
and any potential clearing in the morning hours, there looks to be
enough CAPE that could kick off some thunderstorms, but CAMs aren`t
all sold on this idea. Shear along this cold front is on the higher
end as well if any storms can manage to get together.
Seasonably cold air will move in behind the passing low to start
next week, with temps falling into the low 30s by Tuesday. Some lake-
effect/enhanced snow showers will even be possible along the NW to N
wind snow belts. Temps will trend back towards normal by the middle
to end of the week with highs back near 50 across the UP.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 834 PM EDT FRI APR 22 2022
Expect conditions to lower to MVFR later this evening with the
onset of the rain from an advancing warm front, then conditions
will further lower to IFR after midnight and to LIFR by Saturday
morning behind the warm front. Conditions could lower close to
airport minimums at SAW by 12Z Sat with se flow upslope
fog/stratus. Any improvement during the day on Saturday looks
limited as most terminals won`t improve more than IFR. With
convection being a little delayed along the warm front, it looks
like thunder chances may be limited to CMX and SAW during the late
evening/early overnight hours. Covered this mostly with VCTS.
Expect east to southeast winds to gust up to 28 knots at CMX and
IWD ahead of the front tonight. The passing low-level jet tonight
will also warrant having LLWS in for all the terminals.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 422 PM EDT FRI APR 22 2022
As a sfc low pressure system develops over the Plains, easterly
winds with gusts of 20-30kt should be common through this evening.
As a warm front associated with the low lifts toward Upper MI
tonight, winds will increase further. Expect ESE gale force gusts of
35-40kt to develop from eastern Lake Superior to Passage Island,
mainly at high obs platforms due to the increasing low-level
stability as increasingly warmer air pushes over the chilly marine
modified air close to the lake surface. A few ENE gale force gusts
to 35kt could also occur over far western Lake Superior. Winds will
only relax slightly during the day Sat, and the area of gale force
gusts of 35-40kt will drift n. By mid to late aftn, the gales should
be confined close to the international border. Winds will diminish
to under 20kt over western Lake Superior Sat night and to 20-30kt
across the e as pres gradient slackens. A cold front will the move
across Lake Superior on Sun. Winds ahead of it may continue to gust
to 20-30kt across eastern Lake Superior. Behind the front, winds
will shift w, then nw. As increasingly colder air arrives, expect
these w to nw winds Sun night thru Tue to gust frequently to 20-
25kt, strongest over the e half of the lake. Winds will fall to
around 20 knots or less across the lake by Tuesday evening through
the rest of the week.
With shra/tsra moving across the lake tonight, the pcpn falling into
the cold marine layer will probably lead to some fog development
late tonight/Sat. This fog will then stick around until cold front
passes on Sun.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Gale Warning from 5 AM to 11 PM EDT Saturday for LSZ267.
Gale Warning from 1 AM to 10 PM EDT Saturday for LSZ264-266.
Gale Warning from 3 AM to 11 AM EDT Saturday for LSZ245-265.
Gale Warning from 1 AM to 2 PM EDT Saturday for LSZ244.
Lake Michigan...
None.
&&
$$
SHORT TERM...lg
LONG TERM...JAW
AVIATION...Voss
MARINE...Rolfson/JAW