Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/05/23
Area Forecast Discussion
National Weather Service La Crosse WI
632 PM CDT Tue Apr 4 2023
.DISCUSSION...(Tonight through Tuesday)
Issued at 220 PM CDT Tue Apr 4 2023
Key Messages:
- Strong to severe thunderstorm risk this evening. Hail the main
threat, but wind/tornado concerns for portions of NE IA/SW WI.
- Windy Wed-Wed Night! Gusts upwards of 45 mph expected.
- Cooler end to work week, warming for the weekend into next week.
Freezing lows Thu/Fri but could top 70 degrees next week. Some rain
chances into next week
* STRONG-SEVERE STORM THREAT TONIGHT: hail main threat
Severe storm threat expected to increase later this afternoon as
surface low progresses through Iowa from southwest to northeast.
Over the last couple of hours, WV imagery and surface observations
place surface low passing from north-central KS into southeastern
NE. Attendant warm front is draped from west to east across southern
Iowa to Missouri border with 10-20 degree dewpoint and temperature
differential. Accompanying dry line extends south from surface low
through central KS and OK. Upper level low and trough seen on WV
imagery farther west, in the lee of the Rocky Mountains. Satellite
imagery exhibits widespread fog for the northern half of Iowa this
morning, limiting temperature recovery. Upper level pattern expected
to continue phasing whilst lifting north-northeast through tonight.
Therefore, upper level QG forcing expected to drive surface low
through central Iowa later this afternoon and evening. Subsequent
initial severe storm development expected this afternoon in central
Iowa as surface triple point/low provides initial forcing. Premium
thermodynamics within the warm sector stick to the southern half of
Iowa, more than 8 C/km low and mid level lapse rates, SB CAPE above
2000 J/kg, and CIN less than -50 J/kg. As storms and surface low
progress northeast this evening, they are anticipated to outrun
surface boundary (moving 30 mph northeast over the last couple of
hours) and storm motion pushing 40 mph. Outpacing the surface front
results in elevated storms expected. Later in the evening, the
attendant cold/dry boundary expected to initiate storms through
central into northeast Iowa. While directional shear within the low
levels (0-2km) provides impressive clockwise turning hodographs and
helicity above 700 m2/s2 nearly all night; tapping into said
helicity will be incredibly challenging given low level inversion.
Shear above 1km (1-6km) pushes another 30-40 knots, sufficient for
sustaining supercells.
In summary, all severe weather types will be possible from southwest
to northeast this evening. Local tornado threat is highest in our
far southern counties in northeast Iowa and southwest Wisconsin
where added low level vorticity along warm surface front could be
tapped into, resulting in surface based storms. This threat is
highly dependent on northern extent of surface warm front, however,
given overcast, foggy conditions across much of Iowa early this
afternoon suspect challenging, slow road ahead for aforementioned
surface frontal boundary. Ongoing precipitation north of warm front
expected to reinforce boundary, keeping it south of local forecast
area. Deterministic HRRR trends have been keeping warm front just
south of our forecast area. Severe hail is the primary threat for
much of the forecast area as elevated CAPE and shear suggest
supercellular.
* WINDY WEDNESDAY! Gusts upwards 45 mph expected
Tight pressure gradient post the departing low pressure system
promises a windy Wednesday-Wed night. Cold air in the mid levels
gradually erodes the inversion, promoting mixing by the afternoon.
RAP bufkit soundings suggest 35-40 kts of wind could be brought to
the sfc. Afternoon-evening instability implies convective elements =
probably more of a cu field rather than extensive showers - but
drying in the sub cloud layer would further enhance the gustiness.
HREF suggests a 30-50% chance for 45 mph gusts dotting parts of SE
MN and north-central WI...but nearly nil for 50 mph.
At this time, border line need for a wind advisory for a few areas.
Confidence not high enough to issue one as of yet. Will continue to
monitor short term trends.
* COOL END TO WORK WEEK, WARMER WEEKEND
Colder, Canadian air spreads southward across the upper mississippi
river valley post the storm system tonight. 850 mb temps progged to
drop as cold as =10 C and sub freezing lows are expected for Thu/Fri
mornings. Most locations won`t warm out of the 40s during the day
Thu.
The cold is short-lived though with GEFS/EPS shifting a shortwave
ridge eastward from the plains to across the region for the weekend.
The medium range guidance then suggests a broader, more longwave
ridge will setup shop for next week. 850 mb temps will flip, with
+10 to +15 C favored. Could see highs push north of 70 degrees for
some locations by the middle part of the new week.
* ADDITIONAL RAIN CHANCES FOR WEEKEND-NEXT WEEK
A few ripples in the upper atmosphere could slip across the region
this weekend and through the middle part of the new week. The GFS/EC
ensemble members showing favor with slipping a shortwave across
northern WI late Fri night/Sat morning, with a west-east running
warm front bisecting the local forecast area. The deeper saturation
progged to hold north of the warm front, fueling pcpn chances with
the shortwave. Current trends hold most of the rain threat
along/north of I-94.
Some push in the GFS and EC for another shot for rain Sun/Sun night.
Not all their respective ensemble members agree, and there are
differences in timing, location, and how/where the pcpn would
respond to the forcing. Confidence lower in sensible weather
outcomes as a result.
More model differences as we move into the new work week. but both
point to some potential to work some shortwaves across/under the
building ridge - with corresponding rain chances.
Will run with the model blend for chances.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 632 PM CDT Tue Apr 4 2023
A strengthening low pressure area will move northeast the area
tonight. CAMs continue to show that there will be a threat for
thunderstorms...possibly severe...between 0030Z and 0300Z for
KRST and between 0030Z and 0600Z. The main severe weather threat
is large hail associated with left moving supercells. Visibilities
will remain IFR/MVFR due to heavy rain and fog.
After the storms move out of the area, ceilings will remain
IFR/MVFR and visibilities will improve to VFR.
Expect winds to become gusty on Wednesday morning and continue
into the afternoon. Expect west wind gusts of 30 to 40 knots.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
DISCUSSION...JAR/Rieck
AVIATION...Boyne
Area Forecast Discussion
National Weather Service Binghamton NY
1009 PM EDT Tue Apr 4 2023
.SYNOPSIS...
A warm week is ahead with multiple chances for rain showers.
There is the potential for a few thunderstorms Wednesday
afternoon into Thursday. High pressure builds in at the end of
the work week, bringing drier and cooler conditions through the
weekend.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
With the late evening update, temperatures have trended a little
cooler for the overnight with a more aggressive push of the
front. The position of the front tomorrow still has more
uncertainty than ideal with a 4 standard deviation spread for
high temperatures Wednesday. Tightened up the temperature
gradient as west of the front boundary layer modeled
temperatures indicate the possibility of highs from 75-80 west
of Elmira. Cold air damming and a marine layer east of the front
should keep temperatures down in the 50`s and some 60`s for
most locations east of I-81.
Early this evening a frontal boundary is currently crossing the
PA/NY line as seen with recent wind shifts to northeasterly in
the Twin Tiers region. This front is still expected to push a
bit further south through the evening into the overnight hours
before setting up as more of a backdoor front on Wednesday.
400 PM Update...
A stationary front sits south of us this evening into tonight,
this produced a tight temperature gradient over our CWA oriented
North/South. As the sun sets, this temperature gradient
subsides and the stationary front pushes out.
Wednesday is going to be an active day as a large, deep low
pressure system over the central US will control the weather
pattern for our CWA. The stubborn stationary front will turn
into a warm front and push northward, putting our area in the
warm sector of the low pressure system off to our west by early
Wednesday morning. A weak shortwave will move through the area
Wed morning, allowing for some scattered rain showers and cloud
cover to develop across areas west to I-81 into the late morning
hours.
0-6km bulk shear of 40-45kt will develop across the western
counties Wednesday afternoon, and the hodograph shows nice
turning with height. The limiting factor here will be cloud
cover and rain showers from the morning limiting heating,
combined with a warm nose between 925-850mb creating a cap over
the area during the afternoon hours. Model guidance is not
settled on how the afternoon will play out, with the NAMNest
showing a strong cap in place. A surface temp around 80F would
be needed to break the cap, which is above the current forecast.
The HRRR has a much weaker cap that can be overcome quite
easily, which would allow for supercells to develop across
western NY and into our western counties, with non- zero chances
for tornados and damaging winds. Current thinking is that with
the shortwave moving through the area, there will be enough
cloud cover to keep temps down and instability low. We will have
to monitor the 925-850mb warm nose trends as this will play a
big factor in whether we can get afternoon convection going.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
3 PM update...
Models have slowed down the cold front so now it will be
crossing NEPA and the Catskills Thursday. Thunderstorms are
possible along and ahead of the front. Temperatures rise into
the 60s and 70s in this area creating low level instability. SPC
has the far south in a marginal chance of severe thunderstorms.
Showers are possible everywhere in the morning then this sides
south across the area during the day.
Thursday night a strong northwest flow of colder air will start.
Air aloft is cold enough to increase cloud cover into Friday. A
secondary cold front could bring some sprinkles on Friday. Skies
will become partly cloudy Friday night.
For temperatures lows will be in the 30s Thursday night, then
rise into the 40s in CNY and 50s in NEPA Friday. Lows will be
mostly in the 20s Friday night.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
3 PM update...
Sprawling high pressure will be centered over the area Saturday
night. The high moves off the coast late Sunday setting up a
warm southerly flow through at least Monday. Models don`t agree
on when a cold front might go through. There is slight chance
pops starting Monday afternoon. High temperatures Saturday from
the mid 40s to low 50s rise to the 60s for Monday and Tuesday.
Lows Saturday night in the 20s to around 30 rise into the 40s.
Extended warm/dry conditions could be of interest to fire
weather concerns, but winds look to be fairly light through the
weekend. Monday winds increase to 15 mph with relative humidity
between 30 and 45 percent.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
VFR will continue overnight. A marine layer will move into the
region and will bring lowering ceilings at all terminals
Wednesday morning, starting around 12z at most terminals.
Restrictions will be mainly MVFR to Fuel Alt. However, IFR
ceilings will be possible at BGM by midday. There is some model
guidance that wants to take AVP down to IFR as well, but
confidence was too low given that the southeasterly winds
usually do not result in ceilings that low. Some improvement
will occur at some terminals near the end of this TAF period.
Scattered rain showers are possible Wednesday afternoon/evening
at SYR and RME. With these showers, ceilings may be IFR at RME
for a few hours and visibilities will likely be reduced at both
terminals. There is uncertainty with the timing, so that will
have to be fine-tuned in future updates.
Easterly winds will be calm to start but gradually become
stronger and more southerly Wednesday morning. Gusts of 20 to 30
kts are expected through the daytime hours tomorrow. Low-level
wind shear (LLWS) will be present at ELM and SYR.
Outlook...
Wednesday Night...Lingering restrictions with showers and
isolated to scattered thunderstorms. Low-level wind shear also
possible.
Thursday...Showers and associated restrictions; low chance for
daytime thunderstorms.
Friday through Sunday...Mainly VFR expected.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...JTC
NEAR TERM...DJN/ES/MWG
SHORT TERM...TAC
LONG TERM...MPH/TAC
AVIATION...BTL
Area Forecast Discussion
National Weather Service Denver/Boulder CO
805 PM MDT Tue Apr 4 2023
.UPDATE...
Issued at 805 PM MDT Tue Apr 4 2023
Water vapor satellite imagery showed a wave rotating over south
central Wyoming this afternoon. This wave and upslope flow helped
produce the snowfall this afternoon and evening. Water vapor
satellite now showing the circulation with this wave fizzling out
and with that the snow has been on the downward trend over northern
Colorado. Expect snow to continue to decrease through the rest of
the evening and end most places by midnight. Could see the snow
linger slightly longer over the mountains. Will leave the highlights
as is and allow the foothills to expire at 9pm and the mountains at
midnight.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 240 PM MDT Tue Apr 4 2023
Snow is slowly coming to an end across the plains this afternoon,
and will continue to decrease in coverage this evening. Water
vapor satellite and RAP mesoanalysis show the upper low departing
to our north, centered over central Wyoming. The KFTG VAD profile
has shown a gradual turn from NNE winds to NNW winds this
afternoon, and coupled with the better synoptic scale lift
departing our region, this has led to an overall decrease in
coverage of snow. Still, shallow convection across the Front Range
has produced some efficient snow rates over the past few hours...
with some unofficial stations reporting close to one inch per
hour in western Boulder county. The HRRR insists on this activity
continuing into the evening hours, and thus no changes to the
current hazard grids are planned.
Chilly overnight lows are forecast tonight, despite some
lingering cloud cover and snow showers. Lows across the high
country will range from the negative to positive single digits,
with 10s forecast across the plains. There`s an outside shot at
DEN reaching its record low (12F, 1983) if clouds clear quicker
than anticipated.
Cool weather will continue into Wednesday. Cloud cover should
redevelop through the afternoon as a weak shortwave approaches the
region. There isn`t any substantial lift (upslope or synoptic
scale ascent) around with this system, but steep lapse rates will
lead to just enough instability for some snow showers,
particularly from the late afternoon into the evening hours. A few
spots across the high country may pick up an inch or two, with
lighter amounts across the lower elevations. Highs across the
plains will stall in the upper 30s to low 40s... which will likely
be the last cool day for quite some time. See the long term
discussion below.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 240 PM MDT Tue Apr 4 2023
Wednesday evening, snow showers linger over the high country.
Scattered showers extend onto the plains in the afternoon. NW flow
aloft will act to work against these showers providing a drier
profile. At most, can see a flurry to a light shower with little to
no accumulation expected. Higher-resolution models hint at a weak
boundary setting up somewhere in proximity to the Palmer Divide
which may help develop weak showers in that area Weds evening. Drier
air works in after midnight as a weak upper level ridge pushes in
from the west. Showers will have diminished in mountains by then and
any remaining stray showers on the plains will diminish as well.
Weak upper level ridging over the region will start the warming and
drying trend Thursday. Temperatures aloft warm several degrees
allowing temperatures to rebound back into the low 50s for a good
portion of the lower elevations. Ensemble guidance supports a
general ridge pattern aloft Friday through the weekend warming highs
into the 60s and 70s. A few models hint at a shortwave moving to the
north of the region Saturday with the GFS tracking it more south
than others, closer to CO. There is a cluster of GEFS members that
exhibit some precip in at least the higher elevations. Overall,
pattern is more favored to stay on the drier side. There is good
agreement with the ridge strengthening towards the end of the
weekend through early next week which will continue to warm
temperatures well above normal. With the help of downslope flow,
highs approaching 80 aren`t even out of the question Tuesday for
the lower elevations which is pretty wild for the time of year.
Unfortunately, with dry and warm comes fire weather concerns.
Elevated fire weather conditions are looking likely for the Palmer
Divide, Lincoln County, and potentially South Park with a chance
for spotty critical conditions.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 546 PM MDT Tue Apr 4 2023
Showers showers should continue to move off the foothills through
mid evening, though slowly decreasing in intensity. MFVR to
occasionally IFR conditions are expected with these snow showers.
Any additional accumulation is expected to be light. The lower
clouds should be slow to scatter with ceilings of 3000-6000 feet
lingering to 09-12Z. VFR to prevail Wednesday morning and early
afternoon, but a weak wave will bring snow showers back for
Wednesday afternoon, after 21Z.
&&
.FIRE WEATHER...
Issued at 240 PM MDT Tue Apr 4 2023
Starting Thursday, upper level ridging will support a warming trend
in temperatures with dry conditions expected. Relative humidity
values will be low during this period with min relative humidity
dropping into the 8-18 percent range for a good portion of the lower
elevations and Palmer Divide, with the lower end values over the
Denver Metro, Palmer Divide, Lincoln County, and possibly South
Park. There is no strong signal for high wind event(s), although
winds may come close to approaching Red Flag criteria along the
Palmer Divide, South Park, and Lincoln County. Elevated conditions
are looking likely in the mentioned areas.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until midnight MDT tonight for COZ031-033.
Winter Storm Warning until 9 PM MDT this evening for COZ035.
Winter Weather Advisory until 9 PM MDT this evening for COZ036.
&&
$$
UPDATE...Meier
SHORT TERM...Hiris
LONG TERM...Mensch
AVIATION...Meier
FIRE WEATHER...Mensch
Area Forecast Discussion
National Weather Service Burlington VT
1027 PM EDT Tue Apr 4 2023
.SYNOPSIS...
A late season winter storm will produce freezing rain across
portions of northern New York north of the Route 11 corridor and
east of the Green Mountain spine on Wednesday. Locally heavy rain is
possible in thunderstorms and could lead to area rivers rising to
bankfull. A cold front crosses the region on Thursday, leading to
more seasonable conditions. High pressure builds in on Friday into
the weekend with mainly dry and pleasant spring weather on tap.
&&
.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
As of 658 PM EDT Tuesday...Forecast remains in good shape for
this evening with a stationary boundary draped across our
southern counties. Isolated light rain showers continue over
Rutland and Windsor Counties associated with this boundary,
while areas further north near the International Border are
dry with clear skies. Made some slight tweaks to precipitation
forecast over the next few hours, but main messaging remains on
track with mixed precipitation to develop for portions of the
forecast area closer to sunrise.
Previous discussion...Forecast for Wednesday remains quite
tricky with our CWA being in the battle zone between the warm
and cold sector. Strong low pressure is progged to lift
northeastward from Minnesota to Hudson Bay, leaving most of our
CWA in the warm sector. However, with a 1040 mb high also
sitting to our north, this will likely mean cold air drainage
down the St Lawrence valley. The National Blend of Models (NBM)
temperature guidance is now a lot more reasonable compared to 24
hours ago, so largely ran with it. The idea is that the
freezing rain threat will be centered across the St Lawrence
valley into portions of the northern Adirondacks Wednesday
morning into the early afternoon hours. 12z CAMs still disagree
with regards to the thermal profile but thinking that with a
1040mb high to our north, the HRRR is too aggressive with
warming the lowest 1000 to 1500 ft of the atmosphere.
Still thinking there will be a sharp thermal gradient between the
NYS thruway and our portion of the northern NY zones due to the low
level cold air damming. It is not out of the question, however, that
we can get elevated convection. So don`t be surprised to see thunder
ice or thunder sleet at some point during the day tomorrow. With
PWATs and IVT between the 99th percentile to maximum of climatology
for our region according to the NAEFS ensemble situational awareness
table, there will be heavy downpours or some kind of heavy wintry
mix during times of elevated convection. Where WPC have the marginal
risk for excessive rainfall looks reasonable, i.e. northern NY into
west of the Greens in VT.
With regards to the precipitation types, expect a few hundredths of
an inch to two tenths of an inch of freezing rain Wednesday morning
into early afternoon, with highest amounts expected mainly north of
the US Route 11 corridor. Admittedly, there are some questions how
effectively the ice could accrete on road surfaces given we have
been quite mild of late. But the dynamics and elevated instability
should allow for moderate to heavy precipitation rates at times,
increasing the potential for at least minor travel impacts. Then by
mid day into the afternoon hours, the threat transitions to Vermont,
especially east of the Green Mountain spine. While 850mb
temperatures rise to above +10C, 925mb temperatures stay sub
freezing at -2 to -4C due to southeast flow. While patchy freezing
drizzle or rain could develop east of the Greens by mid day, the
steadiest freezing rain should occur late afternoon/early evening
into the early overnight hours. Cold air should be toughest to scour
out of the Connecticut River valley, so expect freezing rain to
linger longest there. All said, hoisted Winter Weather Advisories
for the aforementioned regions.
From a hydrologic standpoint, while a few rivers could approach
bankfull, overall, expect the basins to remain below minor flood
stage. It is not out of the question that vulnerable sites like the
east branch of the Ausable River and Winooski River at Essex
Junction could approach or even briefly get into minor flood stage
based on the more aggressive members of the NAEFS ensemble guidance.
The other consideration is that based on our snow surveys, there is
non existent snowpack below 1000 ft across the region and based on
the forecast temperatures, not expecting a significant loss of SWE
in the upper basins of the Adirondacks and northern Greens.
Nonetheless, something to monitor as the event unfolds depending on
how quickly the warm sector advances northwards into our area and if
thunderstorms develop over the basins. But for now, not worried
about the hydrologic risk.
Temperatures are expected to exhibit a non diurnal trend Wednesday
night as we remain firmly in the warm sector out ahead of a
cold/occluded front that approaches from our west by Thursday
morning. There could be a few rumbles of thunder or even a
thunderstorm overnight Wednesday with some elevated instability and
K index values in the 30s.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
As of 340 PM EDT Tuesday...Cold/Occluded front crosses the region on
Thursday, with temperatures back to more seasonable levels. Couldn`t
rule out a few rumbles of thunder or even a thunderstorm Thursday
morning but it looks like the convective coverage should slide south
of our area by mid day Thursday. For reference, typical highs for
early April are in the mid 40s to near 50. High pressure then builds
in overnight Thursday leading to a stretch of mainly quiet weather
for the long term forecast period.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 340 PM EDT Tuesday...Very quiet weather is expected for the end
of the work week and into next week as high pressure over the Great
Lakes Friday will slowly drift east and center over the Northeast
through the weekend. As such, PoPs are basically nil except for
perhaps a slight chance in the mountains on Friday as a shortwave
passes north of the border. The only day with any impactful weather
will be Friday where post frontal passage Thursday night, west-
northwest winds will become quite gusty in the 25-35 mph range.
Depending on how much widespread precipitation we see in the prior
days, fire weather concerns could be heightened considering the
expected wind gusts and RH levels potentially dropping below 30%.
Looking at temperatures through the period, cooler than normal is
expected Friday/Saturday with highs in the mid 30s to mid 40s, and
lows in the teens to mid 20s. As high pressure shifts offshore,
warmer temperatures return for Sunday onward with highs back above
normal in the 50s Sunday, and 50s to 60s Monday/Tuesday.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
Through 00Z Thursday...Several impacts expected to the aviation
community on Weds, which include potential icing, low level wind
shear/turbulence and lowering cigs/vis toward mvfr/ifr in a few
sites. Next 6 hours are quiet with VFR conditions and
north/northeast winds 4 to 8 knots. Clouds lower aft 06z with
MVFR conditions and light freezing rain developing at MSS toward
12z as NE flow increases at 10 to 20 knots. A period of moderate
FZRA is likely on Weds morning into Weds aftn with lowering
cigs toward IFR conditions at MSS with areas of wind
shear/turbulence associated with changing of wind direction and
speed with height. Also, a rumble of thunder is possible. Meanwhile,
CIGS lower to MVFR conditions at most other sites by 18z with
areas of -ra, but -fzra is likley at MPV/EFK with sfc temps
hovering near freezing and vis ranging btwn 4-6sm in the precip.
Areas of wind shear and turbulence wl prevail thru the
afternoon hours as southeast winds increase at 15 to 30 knots
here in the CPV. Also, southeast flow off Lake Champlain could
provide PBG with localized IFR cigs midday Weds.
Outlook...
Wednesday Night: Mainly MVFR, with local IFR possible. Definite
RA, Definite FZRA, Isolated TSRA.
Thursday: Mainly VFR, with local IFR possible. Likely RA.
Thursday Night: VFR. NO SIG WX.
Friday: VFR. Windy with gusts to 30 kt. NO SIG WX.
Friday Night: VFR. NO SIG WX.
Saturday: VFR. NO SIG WX.
Saturday Night: VFR. NO SIG WX.
Sunday: VFR. NO SIG WX.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...Winter Weather Advisory from 11 AM Wednesday to 5 AM EDT
Thursday for VTZ003-004-006>008-010-016>021.
NY...Winter Weather Advisory from 5 AM to 5 PM EDT Wednesday for
NYZ026-027-030-031-087.
&&
$$
SYNOPSIS...Chai
NEAR TERM...Chai/Duell
SHORT TERM...Chai
LONG TERM...Lahiff
AVIATION...Taber
Area Forecast Discussion
National Weather Service Columbia SC
951 PM EDT Tue Apr 4 2023
.SYNOPSIS...
The warming trend will continue through Thursday with well above
normal temperatures expected Wednesday and Thursday. A slow
moving frontal system will move into the region late Thursday
into Friday then stall across the region with much cooler and
rainy weather expected this weekend. Gradual improvement is
expected with warming temperatures next week.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Cloud forecast is tricky across the area tonight, and that will
also have an impact on temps and fog potential.
First, the mass fields show a quite amplified ridge over the
eastern third of the country tonight. This ridge will modulate
the clouds on three levels.
In the upper levels, a strong jet is transporting moisture from
the east tropical Pacific into the center of the country.
Overnight, that cirrus cloud deck should start to spill over the
upper ridge and start moving into the CWA after midnight. I
don`t thick it will be too thick, but it will be a pain to those
who plan on stargazing later on tonight.
In the 850-500 MB layer, very dry air is the rule with
subsidence under the upper ridge. Given the strength of the high
aloft, I do not see much in the way of moistening in that level,
so mid clouds and precipitation are unlikely overnight.
In the near surface layers, decent moisture will get trapped
under the diurnal inversion. This will create a mix of low
clouds and fog. Given a lack of any low level jet, fog seems
more likely in the fog prone areas, so I will continue with
patchy fog in the grids after midnight.
Overnight lows will be on the mild side as dewpoints have
climbed into the 60s today, creating a floor for the temps.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
Wednesday and Wednesday Night: Upper ridge continues to strengthen
with a west to southwest flow developing aloft. At the surface,
offshore high pressure will produce southeasterly winds over the
forecast area. This pattern will result in increasing Warm Air
Advection over the CWA with well above normal temperatures expected.
While moisture will gradually increase, guidance continues to
suggest a stout dry layer will exist between 600mb and 900mb keeping
the region dry. Highs will be in the mid to upper 80s. Clouds will
increase Wednesday night ahead of the next storm system. This
combined with ongoing WAA will limit nocturnal cooling with lows in
the mid to upper 60s.
Thursday and Thursday Night: Southwesterly flow continues aloft as
the center of the ridge drifts east. Meanwhile, a surface cold front
will slowly approach the forecast area from the north and west. Rain
chances gradually increase through the day and into Thursday night
with the best chance for thunderstorms over the northern and western
counties where the best lift will be. With plenty of clouds around,
temperatures are expected to be a couple degrees cooler than
Wednesday but still above normal. Highs will be in the lower to mid
80s with lows in the mid 50s to lower 60s.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
The cold front continues to move sluggishly into the region on
Friday. While there is still uncertainty regarding the timing
of the boundary, the potential for several rounds of moderate to
perhaps heavy rainfall is increasing, especially on Saturday.
Strengthening surface high pressure to the north may also
produce breezy conditions through the weekend. This pattern
could result in the development of a wedge over portions of the
forecast area strengthened further by Cold Air Advection and
rain. Temperatures on Friday are expected to be noticeably
cooler than Thursday and will depend on how much progress the
front makes. Saturday will likely be the coolest day with well
below normal temperatures expected. Conditions should gradually
improve Sunday with decreasing rain chances though a few showers
cannot be ruled out into early next week. After a raw Saturday,
a warming trend is expected next week.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
Updated to amend AGS. AGS fogging up early with clear skies and
light winds. Satellite loop indicates some high level cloudiness
coming in by 05 or 06z, which may allow VSBYs to improve some,
until stratus and possibly fog can move in late tonight.
A surface high pressure ridge axis will stretch near the coast
or offshore through tonight, with a cold front and strong area
of low pressure well to our W/NW. Expecting light surface winds
overnight, but a southerly boundary layer wind could reach 20
kt, per latest BUFKIT time height displays, due to a slightly
tighter surface pressure gradient over our forecast area (FA).
Satellite loops and model guidance indicate some high level
cloudiness could stream east into our FA later tonight, possibly
favoring northern areas due to a building upper ridge over our
region. So, lighter winds and possibly less cloud cover, along
with some low level moisture enhancement from sea breeze
penetration, could explain why both SREF and HRRR have been
favoring fog/stratus mainly over the coastal plain tonight,
though shifting it north towards daybreak towards our
southernmost TAF sites DNL/AGS/OGB. However, most recent runs of
HRRR indicating areas of patchy fog northern areas as well. For
now, will indicate restrictions at all TAF sites, but reserve
the lowest restrictions for OGB/AGS.
After morning fog/stratus dissipates, VFR expected Wednesday with
increased SW winds. Diurnal Cu, with bases above VFR level, possible
in the afternoon.
EXTENDED AVIATION OUTLOOK...CIG restrictions expected Wed nt/early
Thu. Widespread prolonged CIG restrictions possible Friday
afternoon through Sunday morning, with reduced VSBYs in rain at
times through the period.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
Area Forecast Discussion
National Weather Service Charleston SC
903 PM EDT Tue Apr 4 2023
.SYNOPSIS...
High pressure will extend across the region into mid week. A
cold front will shift across the area late Thursday through
Friday. High pressure will then prevail through the middle of
next week.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Unfortunately, the fog forecast still remains quite muddled
with a number of possible outcomes noted in the various
gridded and statistical data sets this evening. The various
members continue to struggle with initialization issues along
the coast and nearby Atlantic waters where several suggest
widespread fog/stratus should be ongoing at this hour. This
continues to point of a lower than normal confidence on the fog
forecast and how it evolves overnight. The 04/23z RAP and H3R
1000 hPa condensation pressure deficit fields are starting to
align a bit more and are trending lower, especially in the KJES-
KLHW-KSAV-KNBC-KJZI corridor, but this trend has only recently
started to materialize. Given the above and what was outlined
earlier with the early evening update, no major changes will be
made to the fog forecast for the late evening update cycle.
High pressure will extend across the region tonight keeping a
warm, southerly flow in place. The boundary layer looks to
decouple later this evening once the weak resultant sea breeze
circulation breaks down. This will result in calm to
light/variable winds overnight. Boundary layer moisture is
expected to slowly build through the night as extensive mid-
level dry air holds in place aloft. This could yield varying
degree of fog early Wednesday morning. How widespread and
potentially dense this fog becomes is still very uncertain with
a number of mixed signals noted in the various statistical and
gridded data.
Light winds and rich boundary layer moisture under very dry
mid-levels are favorable for radiation fog development, but
1000 hPa condensation pressure deficits noted in the various
near term models such as the RAP are a bit too high to support
significant fog formation. However, SREF/HREF vsby progs show
fairly high probabilities for reduced vsbys (50-80% for vsbys
<1 mile), matching trends noted in the GLAMP, RAP and NAM12,
but much of this is predicated on some degree of fog and stratus
having already forming over the coastal waters this afternoon
and advecting onshore later this evening/overnight. Coastal
webcams and visible satellite images show none of this
fog/stratus has come to fruition so far so a number of the more
dependable models for fog are already initiating too bullish.
This overly aggressive formation of fog/stratus over the
coastal waters has been plaguing the models during much of the
2022-2023 cold season, so it remains unclear if enough
favorable fog parameters are in place to support a significant
fog event overnight. Given the above noted discrepancies, the
previous areas qualifiers of "patchy and "areas of" were
maintained from the previous forecast cycle, with some minor
adjustments for timing. Hopefully, some sort of definitive trend
will begin to establish itself later this evening to see in
which direction the forecast needs to be adjusted to.
Lows from the lower 60s well inland to the mid-upper at the
beaches look on track.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
Wednesday and Thursday: High pressure will prevail along with dry
weather and warm temperatures. Highs across inland areas will be in
the mid to upper 80s to low 90s. Along the immediate coast, mid to
upper 70s are expected. Low temperatures will be in the 60s.
Thursday night and Friday: Overnight Thursday, a cold front will
approach the region then move slowly across the area on Friday.
While there are some indications of a few showers popping up
overnight Thursday, at this time, the forecast features POPs <15%.
But come daybreak Friday, precipitation activity should quickly ramp
up and persist through the day. While the parameters aren`t all that
impressive, have left mention of thunderstorms in the forecast as
well. Another challenge of the day will be the high temperatures.
They will depend greatly on how quickly the front gets into the area
and moves through. For now, have high temperatures in the mid 70s to
mid 80s, with the warmer temperatures further south.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A cold front will move further away from the area overnight Friday
as high pressure builds in behind it. But, plenty of moisture will
stick around on Saturday as well as shortwave energy so expect
another wet day. At this time, with limited instability to work with,
have opted to leave out any mention of thunderstorms on Saturday.
Rainy conditions should gradually taper off into Sunday. Although,
there are indications that enough moisture will linger across the
area and isolated showers could continue into Tuesday. As of note,
gusty winds could support a Lake Wind Advisory late Friday into
Saturday. Otherwise, high temperatures will be in the mid to upper
50s inland with 60s to low 70s closer to the coast and across SE GA
on Saturday then warm each day thereafter. Low temperatures will
generally be in the 40s to 50s.
&&
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
KCHS/KJZI/KSAV: Low confidence on the fog/status forecast
overnight. Conditions are somewhat favorable for fog/stratus
development overnight under mostly clear skies and light winds.
However, most of the guidance has initiated poorly this
afternoon as many members are already suggesting fog/stratus
should be in place over the coastal waters, which would spread
inland overnight. Satellite and webcams along the coast show no
indication of the fog/stratus formation as of yet, so this is
leading to well below normal confidence on how the fog situation
will evolve overnight. Some of the incoming short term
statistical guidance has backed off on the fog ever so slightly,
so the 00z TAFs will be trended slightly more optimistic until
a more definitive trend can be established. All three terminals
will feature vsbys dropping to MVFR by 08-9z with TEMPO groups
bringing vsbys right to or just below airfield minimums. KJZI
will prove the most difficult as given its proximity to the
Stono River, prevailing conditions below airfield minimums is a
distinct possibility. Fog/stratus should mix out shortly after
daybreak with VFR prevailing thereafter.
Extended Aviation Outlook: VFR will prevail through Wednesday.
Thereafter, flight restrictions will be possible in low clouds
and/or showers and thunderstorms.
&&
.MARINE...
Tonight: The marine zones will remain between high pressure
centered over the western Atlantic and a developing area of low
pressure over the Great Plains. This pattern should support
light southeasterly winds between 4-8 kt across the coastal
waters tonight. Seas will remain 2-3 ft. Areas of fog could
develop across the nearshore waters out to 20 nm tonight and
perhaps becoming dense at times. Beyond 20 nm, SSTs are close to
the upper 60s, limiting fog from developing well offshore.
A Dense Fog Advisory could be required for the nearshore
waters, including the Charleston Harbor.
Wednesday through Sunday: High pressure will prevail through
Thursday before a cold front impacts the region through early
weekend. Winds and seas will be 5 to 10 knots with seas less than 3
feet through early Friday. Then, winds will pick up to 20 to 25
knots with seas 5 to 10 feet and persist into Sunday. Small Craft
Advisories will be needed but there are also indications that Gale
Watches/Warnings could also be needed.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.
&&
$$
Area Forecast Discussion
National Weather Service Duluth MN
627 PM CDT Tue Apr 4 2023
.DISCUSSION...(This evening through Monday)
Issued at 408 PM CDT Tue Apr 4 2023
Summary: A large spring storm is crossing the Northland today and
Wednesday. Afterwards the weather quiets down a bit.
So much going on and not much that hasn`t already been said. Will
cover the significant changes and potential outcomes in this
discussion.
First off, the thunderstorm threat has expanded northward and
will likely persist into Wednesday morning - even as far north as
Ely, MN. The severe thunderstorm threat has maintained its extent
to just NW WI. Some of the storms have decent UH tracks overnight
though all elevated of course, so the main threat is large hail.
HREF paintballs have one period of thunderstorms cross NW WI this
evening with the next one to cross further west Wednesday morning.
Radar keeps lighting up with waves of convection bringing small
hail this afternoon though MUCAPE is still quite small (sub 500
J/kg). Just now, some new cells started to fire in SW Iowa. 850mb
moisture transport is quite high through central Wisconsin
advecting northwestward, but satellite imagery also shows a fairly
stout dry slot approaching from the southwest. This lends some
uncertainty to the forecast as the HRRR has trended downward with
QPF, but several other models continue to develop convection, so
will ride with the current stable forecast. The present radar
trend does suggest that the dry air may be winning the fight
though - at least for now. The elongated area of low pressure is
still back in central Kansas and is still expected to pivot
northward as suggested by all the mainstream guidance; however,
the spread in the ensemble member track is still quite varied
especially between the Euro and GFS camps with some of the Euro
members tracking the central low of this system as far east as the
Keeweenaw Peninsula. This bodes well for minimizing icing
potential in our area, but also may bring some more snow further
east than forecast. Either way, there still should be a mess of
ptypes out there and will maintain all current headlines. In fact,
expanded them a little to cover the potential for significant ice
accumulations south of Duluth along I-35 and across portions of
NW WI that straddle the above freezing air. The one thing in all
of this that is working out well is the wind forecast where a 61
mph gust was recorded on Park Point with large waves have already
been pummeling the shore and causing some road closures near the
DECC.
So, all this to say that the current forecast tries not to veer
too far from what we`ve been advertising, but there is some doubt
in the QPF placement and thus the total impact of the storm. NW WI
still looks like a good bet for a lot of icing and thunderstorms
and possibly flooding due to the ripe snowpack, less confident in
icing along the I-35 corridor and still looks good for the
Blizzard and heavy snow to the northwest portion of our forecast
area.
Afterwards, things quiet down a lot and temperatures may even soar
into the 50s or even the 60s by Monday. A little impulse on a
nocturnal LLJ does force a little activity on Saturday morning
with strong FGen in the region.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 627 PM CDT Tue Apr 4 2023
A Spring Storm system is bringing a mixed bag of weather types and
hazards across the region this evening. Across the far north snow is
favored but as we head farther south we get a mix of snow and sleet.
Very strong winds gusting out of the east tonight, especially at
DLH. There is also a chance for some overnight thunderstorms moving
up from southern MN into NW WI. Precipitation continues into
tomorrow morning but will be tapering off in it`s intensity. Winds
will also be rapidly changing to out of the west and picking up in
speed heading into the afternoon hours.
&&
.MARINE...
Issued at 408 PM CDT Tue Apr 4 2023
A strong spring storm will cross today through Thursday bringing
storm force winds to the waters this evening for easterly winds
and again Wednesday for southwesterly winds as the low crosses
directly over Lake Superior. Storm Warnings and Gales are in
effect through Thursday morning.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 25 36 17 30 / 90 80 40 40
INL 18 30 13 29 / 100 100 80 60
BRD 25 35 16 32 / 90 80 20 10
HYR 32 46 19 33 / 100 60 30 20
ASX 29 42 20 34 / 100 70 30 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...Lakeshore Flood Warning until 10 AM CDT Wednesday for WIZ001.
Ice Storm Warning until 10 AM CDT Wednesday for WIZ001>004.
Winter Weather Advisory until 7 AM CDT Wednesday for WIZ006>009.
MN...Blizzard Warning until 7 PM CDT Wednesday for MNZ010.
Winter Storm Warning until 7 PM CDT Wednesday for MNZ011-012-
018>021-025-026-033>037.
Lakeshore Flood Warning until 10 AM CDT Wednesday for MNZ037.
Ice Storm Warning until 10 AM CDT Wednesday for MNZ038.
LS...Gale Warning until 1 PM CDT Thursday for LSZ121-148.
Storm Warning until 7 AM CDT Thursday for LSZ140>144.
Storm Warning until 10 AM CDT Wednesday for LSZ145>147-150.
&&
$$
DISCUSSION...Wolfe
AVIATION...Britt
MARINE...Wolfe
Area Forecast Discussion
National Weather Service Grand Forks ND
1032 PM CDT Tue Apr 4 2023
.UPDATE...
Issued at 1031 PM CDT Tue Apr 4 2023
The heaviest band of snow has started to show decreasing trends
based to KMVK radar snowfall rates are starting to back off some
with the areal extent of the 1-1.5"/hr part of the band shrinking
and shifting north. When this area was showing 1.5-2.0"/hr rates
it was likely running 0.5"/hr high based on measurements here at
the NWS office and other measured reports. Adjusting for this bias
most areas where the 25-35dbz returns are in place are likely
receiving 0.25-0.5"/hr rates with the higher returns 1.0"/hr.
This is matching up well with the 00Z HREF trends regarding snow
rates are and areal extent of accumulating snow/trends. There
should support a transition to just light snow with pockets of
moderate snow after midnight, with additional pockets of heavy
snow/snow bands redeveloping in MN as the deformation slides east.
Considering what has fallen and HREF means we are in line for the
lower end of current ranges into the morning hours, however if
the heavier bands stall the upper ranges are still possible. 2-6km
lapse rates are well over 8C/km based on objective RAP analysis
supporting these convective snow pockets, so we aren`t out of the
woods for higher rates where those pockets track. Confidence is
still lower in how much additional snow will fall across our
south-southeast through Wednesday, with more in the way of mixed
precip/light icing. Snow trends aside, there should still be a
increase in winds from the west-northwest Wednesday morning into
Wednesday evening, with additional blowing snow/potential blizzard
impacts where the highest winds occur. For now we are holding as
is and will reassess complete 00Z data as it comes in tonight.
UPDATE Issued at 703 PM CDT Tue Apr 4 2023
Organized heavy snow band is pivoting over eastern ND into far
northwest MB with a mid level dry slot over west central MN to the
southeast. This dry slot is deceptive though, as saturated BL
conditions and strong forcing still supports light freezing
rain/freezing drizzle (several reports) and this is not being
sampled by the radar at this range. Ice accretions around 0.1" or
more may be possible through the night where this dry slot lingers.
By 09Z HREF shows the deformation zone sliding east with moderate
to heavy snow possibly filling back where that dry slot is
currently in place. At least for the next 6-9hr impacts may be
more in line with an "advisory" for some of those areas (icy
travel conditions due to the mixed precip) but as the snow rates
pick back up along with winds warning impacts remain possible.
More significant impacts/blizzard conditions are ongoing where
the heavier snow band/bands are tracking this evening which should
continue into the overnight and the morning hours Wednesday.
Within this band whiteout conditions have been reported. Radar
estimates show 1-2.5"/hr within the most organized band. For part
of the day the high solar angle was helping with
settling/melting/compaction of the snow especially on concrete
surfaces, however now that the sun is setting impacts will only
deteriorate as snow accumulations pick up. No major changes were
made to the forecast at this time.
&&
.SHORT TERM...(This evening through Wednesday night)
Issued at 309 PM CDT Tue Apr 4 2023
Key Messages
- The strong Winter Storm will continue across the FA through the
short term period
- Overall impacts are lowering slightly across portions of west
central MN
- The strength of the winds throughout the event continue to lower
slightly
- No changes to headlines will be made on this shift
As of 230 pm today, the main surface low was located down over
southeast Nebraska, where temperatures were in the low 70s. Sioux
Falls was 35F and Fargo 33F. Winds were still from the northeast
and remain on the lower end. The regional radar continues to show
the strongest reflectivity values stretching from north central
SD, through the F-M area, up toward Bemidji. Snowfall rates within
this area have been at least 1 inch per hour (except on the
eastern end near Bemidji). There were even some lightning strikes
earlier from Watertown SD toward the Twin Cities. There is strong
700mb frontogenesis across the southern FA and widespread 850mb
warm advection. So far, have reports of 2 to 4 inches of snow
across portions of southeast ND and west central MN. Interstate 29
has been closed south of Fargo, but surface temperatures over
most of the Red River Valley are still in the mid 20s to lower
30s. Therefore, road temperatures are still quite mild.
Moving into tonight, as the sun goes down, surface and road
temperatures will drop. That will allow the impacts of the snow to
become much greater. For the most part, winds will still be from
the northeast, so don`t anticipate wind gusts being too much of an
issue. The main reason for near zero visibilities will be the
heavy falling snow. The 700mb low still tracks right through the
Red River Valley into northwest MN, so the forcing is there for
steady snow along and west of that corridor. There are questions
as to how much additional snow will fall across the Elbow Lake to
Wadena corridor, with the dry slot working up that way now.
However, with 2 to 3 inches already on the ground and it is still
snowing, with the potential for a little glaze of ice, don`t want
to drop from warnings to advisories too fast. Especially since
temperatures will drop after dark. So no plans to change any
headlines at this point.
For Wednesday into Wednesday night, the snow will slowly taper off
from south to north. Winds will switch from northeast to north to
northwest. This switch is better for stronger winds across the
FA, so this looks like the best time frame for gustier winds and
any blowing snow. That said, did continue the trend of lowering
speeds slightly throughout this period. Think wind gusts of 40 to
45 mph are still possible, mainly from Devils Lake through Valley
City, potentially into the southern Red River Valley. This is not
January, and there are no subzero temperatures surging in behind
the system. Temperatures during this period look to be in the
teens to lower 20s, which reduces the overall impact of blowing
snow slightly (than say if it was 10 to 20 below zero). So the
heavy amounts of snow will be what makes the recovery time slower.
The exact degree of the blowing snow impacts look a little more
uncertain overall.
.LONG TERM...(Thursday through Tuesday)
Issued at 309 PM CDT Tue Apr 4 2023
Key Messages:
-A gradual warming trend is expected through the weekend into early
next week.
-Mostly quiet weather looks to persist across the long term period.
Discussion...
The overall synoptic pattern across the long term period will
feature generally large scale ridging aloft. Prior to this ridging
building into the region though, the upper level trough affecting
the area across the midweek period looks to lift eastward into the
Great Lakes. Following the passage of this trough, a brief period of
northwesterly flow aloft ahead of the building ridge will work to
keep temperatures on the cooler side through the end of the week.
Resultant high temperatures in the 20s to low 30s are anticipated on
Thursday. After a cold start to Friday, with low temperatures in the
single digits to near zero, a slight warm up into the upper 20s to
mid 30s is then expected. Moving into the weekend, the large scale
ridging aloft should work to keep the weather quiet and temperatures
on a gradual warming trend into early next week. Widespread high
temperatures in the 30s to 40s will be possible across the weekend,
with all indications that widespread 40s will be possible by early
next week alongside a few readings in the 50s within the Minnesota
trees. Otherwise, there are some faint signals for light rain on
Sunday as a weak, open wave trough moves across southern Canada.
Despite this, the majority of ensemble guidance keeps the area dry,
with probabilities for greater than 0.1" of QPF less than 10%.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 703 PM CDT Tue Apr 4 2023
VLIFR conditions continue as heavy snow and blowing snow has
overspread much of eastern ND and far northwest MN. Away from the
heavier snow back mixing precipitation (freezing drizzle/snow) is
also occuring along with IFR ceilings. Expect the heaviest snow to
eventually lighten up by late Wednesday morning, however west-
northwest winds increase leading to additional impacts from
blowing snow (especially in eastern ND).
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...Blizzard Warning until 7 AM CDT Thursday for NDZ006>008-014>016-
024-026>030-038-039-049-052>054.
MN...Blizzard Warning until 7 AM CDT Thursday for MNZ001>005-007-008-
013-014-029.
Winter Storm Warning until 7 AM CDT Thursday for MNZ006-009-
015>017-022>024-027-028-030>032-040.
&&
$$
UPDATE...DJR
SHORT TERM...Godon
LONG TERM...Rick
AVIATION...DJR
Area Forecast Discussion
National Weather Service Fort Worth TX
539 PM CDT Tue Apr 4 2023
...New Short Term, Aviation...
.SHORT TERM... /NEW/
/Through Wednesday Evening/
A broad upper trough remains entrenched across the Rockies, with
a lead shortwave progged to lift northeast through the Plains this
evening. At the surface, a dryline has just recently pushed east
through Abilene and entered our far western counties, with a cold
front taking shape across Colorado and Kansas. The dryline has
been a bit slower to push east than originally thought, which has
actually helped to mitigate wildfire danger across the western
counties. There will still be a window now through sunset for
elevated fire danger roughly along and west of Highway 281.
Despite a volatile environment east of the dryline, convective
initiation has been shut-off due to the presence of a strong
capping inversion around 850mb. There still may be an isolated
storm or two which may overcome this convective inhibition, in
which case all modes of severe weather would be possible. Recent
runs of the HRRR have held onto this notion, so we will still need
to monitor the dryline over the next few hours.
Better chances for thunderstorms will arrive during the overnight
period as the cold front pushes south into the forecast area.
Recent guidance is fairly consistent with indicating rapid
convective development somewhere near the I-35 corridor in the 2
to 3 AM time frame along the front. Storms will likely develop
quickly upscale while pushing east through the eastern half of the
region Wednesday morning. Hail and damaging winds will be the
main hazards, though a qlcs tornado or two may also occur before
activity winds down by mid morning.
Seasonable temperatures and drier conditions are expected behind
the front for most of the region. The exception will be for parts
of Central Texas, which will be just north of the location where
the front is progged to become stationary. Broad troughing will
be lingering over the southern Rockies, creating southwest flow
aloft and eventually generating isentropic lift over the frontal
layer. Showers and elevated storms will be the result over Central
Texas, starting mainly after midnight Wednesday night.
30
&&
.LONG TERM... /Issued 315 PM CDT Tue Apr 4 2023/
/Wednesday Night through Early Next Week/
An unsettled weather pattern will continue through the rest of
the week with daily rain chances and below normal temperatures.
Our region will remain under the influence of a large upper level
trough sending a couple of disturbances over our region. At the
surface, we will see tomorrow morning`s cold front slow down and
become nearly stationary along the Texas Coast. The combination
of the surface boundary and passing waves will bring additional
large scale ascent for multiple rounds of showers and storms
across our region. As mentioned in previous discussions, areas
across the Brazos Valley will have the highest potential (60-80%
chance) for widespread rain. Latest guidance continue to
highlight rainfall totals between 2-4 inches confined across our
southern counties. Confidence is increasing that many locations
will receive at least 2 inches of rain through Friday night (both
the NBM and WPC guidance shows a probability of 70-80%). Periods
of locally heavy rain Wednesday night through Friday night may
result in isolated higher amounts closer to 5 inches. Flooding
concerns will increase if we start seeing cluster of
showers/storms occurring over the same locations. Forecast
updates should be monitored as details will continue to be
refined. No severe weather is expected at this time. Otherwise,
locations north of the I-20 corridor will only see some light rain
or remain dry through most of the week. Our temperatures during
this period will stay below normal with highs only in the upper
50s to mid 60s Thursday and Friday.
After this active period, we will see a more zonal flow aloft
persisting over the weekend with dry weather and slightly warmer
temperatures. Nice and pleasant conditions are anticipated on
Easter Sunday with light winds and highs in the mid to upper 70s.
A few locations across the west could see some low 80s. The dry
weather will continue into early next week along with a warming
trend (highs in the 80s).
Sanchez
&&
.AVIATION... /NEW/
/00Z TAFs/
Cigs continue to erode and will give way to VFR through at least
midnight local tonight. A cold front will arrive during the
overnight hours, with FROPA in the DFW Metroplex around 08Z, and
KACT 09-10Z Wednesday. A brief round of MVFR just ahead of the
front and brief round of ts with the front can be expected,
followed by northwest winds and VFR for the rest of the forecast
period.
30
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 58 71 49 65 49 / 50 5 0 10 30
Waco 61 72 50 60 49 / 70 20 10 40 60
Paris 59 69 47 60 47 / 80 20 5 10 20
Denton 53 68 43 65 44 / 30 0 0 5 20
McKinney 56 69 45 63 46 / 60 5 0 10 20
Dallas 61 72 49 64 50 / 60 5 0 10 30
Terrell 59 71 48 61 49 / 80 20 5 20 40
Corsicana 61 73 50 60 49 / 80 30 20 30 50
Temple 59 75 49 60 49 / 70 20 20 50 70
Mineral Wells 52 71 44 67 46 / 10 0 0 10 30
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Wichita KS
618 PM CDT Tue Apr 4 2023
.SYNOPSIS...
Issued at 424 PM CDT Tue Apr 4 2023
There is a trough from the Plains to the southern Rockies. The
associated cold front is on the move between Ellsworth and Salina
then between Lyons and Hutchinson. There is a dryline through south
central Kansas which has begun to retreat westward through the
afternoon. A contrast in temperatures exists with values around 80
degrees in southeast Kansas to near 90 in south central Kansas and
in the lower 60s in north central Kansas.
Strong winds and drier air still pose a fire weather threat
specifically in portions of north central and south central
Kansas at least for the next few hours. Thus the Red Flag Warning
and Wind Advisory remain for now. They may need to be cancelled
earlier behind the cold front. This can be assessed by the evening
shift.
&&
.SHORT TERM...(This evening through Friday night)
Issued at 424 PM CDT Tue Apr 4 2023
Highlights:
1) Chances for severe thunderstorms through the Flint Hills into SE
KS tonight
2) Freezing temperatures early Wed & early Thur
3) Cooler Wed & Thur
Changes:
1) Timing of cold front - winds, dewpoints & temps
2) Westward extent of precipitation chances
Challenges:
1) Timing cold front
2) Westward extent of convection
Severe thunderstorms remain possible this evening and tonight as the
trough strengthens with its northeast movement to the Northern
Plains. Surface based CAPE is expected to be around 2-3k J/kg with
effective bulk shear of 50-70kts. CAMS suggest development will
occur along the cold front with initially a discrete mode before
quickly transitioning to a linear mode. Initialization is around 2-
4Z(9-11PM) with an exit of Kansas by around 9Z(4AM). However, the
cold front is quickly moving southeast with the dryline retreating
further west this afternoon. Thus development very well may occur
quicker. These short term convective models have different locations
for the initial development with some further back to the west
even closer to the Kansas Turnpike (Wichita Metro) according the
NAM Nest while others highlight the Flint Hills and points east.
Discrete initial development could present the possibility for all
hazards (large hail, damaging winds and tornadoes); this
development may occur in northeast Kansas with more a linear
threat as the cold front fills in towards south central and
southeast Kansas. However, the HRRR suggests discrete cells
through the Flint Hills first. If the timing occurs after dark, it
is extra important to have ways to be alerted and consider
checking the forecast before heading to bed tonight especially
those in the Flint Hills into southeast Kansas. Additionally make
sure to have ways to receive warnings if you have outdoor plans
this evening.
Cooler air will surge southward behind the cold front and drop
temperatures into the mid 20s to lower 30s in north central Kansas
with values in the upper 20s to mid 30s in south central Kansas.
Given the recent warm up, the decision was to put the areas that
will drop into the upper 20s into a Freeze Warning. Breezy winds
should prevent frost potential. If you have been proactive in
planting, you will want to cover or take in any sensitive flowers or
plants in north central and south central for at least the next
couple of nights.
.LONG TERM...(Saturday through Tuesday)
Issued at 424 PM CDT Tue Apr 4 2023
Highlights:
1) Gradual warm up
2) Slight chances for showers and storms Sun eve-early Mon
A ridge moves in for Friday and Saturday. There is a weak wave
expected to move through late Saturday to Sunday. This could lead to
possible showers and thunderstorms. Confidence is lower with this
potential so stay tuned. A warming trend is anticipated through this
part of the forecast with afternoon high temperatures back near 80
degrees for Easter Sunday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 618 PM CDT Tue Apr 4 2023
A strong cold front will move from south central and northeast
Kansas across southeast Kansas through early tonight. Scattered
strong to severe convection is expected ahead of the front during
the mid to late evening hours. Strong south to southwest winds
ahead of the front will shift to north-northwest and remain quite
strong behind the front tonight into early Wednesday. MVFR/IFR
vsbys in rain and patchy MVFR cigs can be expected ahead of the
front with any convection and a transient patch of mainly VFR
cigs just behind the frontal passage. Otherwise, diminishing north
to northwest winds and VFR conditions expected on Wednesday.
KED
&&
.FIRE WEATHER...
Issued at 424 PM CDT Tue Apr 4 2023
Strong winds and drier air still pose a fire weather threat
specifically in portions of north central and south central
Kansas at least for the next few hours with extreme to
catastrophic on the Grassland Fire Danger Index. Thus the Red
Flag Warning remains for now. It may need to be cancelled earlier
behind the cold front. This can be assessed by the evening shift.
Very high grassland fire danger persists into the nighttime hours.
On Friday and Saturday, there is potential for very high fire
danger in north central and portions of south central Kansas as a
gradual warming trend occurs. Minimum relative humidities are
expected to be in the upper teens to lower 20s on Friday and the
20s on Saturday. Afternoon wind speeds are expected to range from
15 to 25 mph.
&&
.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT 34 55 32 61 / 10 0 0 0
Hutchinson 30 53 28 60 / 10 0 0 0
Newton 32 53 29 61 / 20 0 0 0
ElDorado 34 54 32 61 / 30 0 0 0
Winfield-KWLD 36 57 33 63 / 20 0 0 0
Russell 26 51 24 61 / 10 0 0 0
Great Bend 26 52 24 60 / 10 0 0 0
Salina 31 53 26 61 / 10 0 0 0
McPherson 30 53 26 60 / 10 0 0 0
Coffeyville 42 58 35 61 / 40 0 0 0
Chanute 40 56 34 61 / 60 0 0 0
Iola 38 55 33 60 / 60 0 0 0
Parsons-KPPF 41 57 34 61 / 60 0 0 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 11 PM CDT Tuesday for north central, south
central and most of southeast Kansas.
Wind Advisory until 1 AM CDT Wednesday for KSZ032-033-047>053-
067>072-082-083-091>096-098>100.
Freeze Warning from 3 AM to 9 AM CDT Wednesday for KSZ032-033-
047-048-050-067.
&&
$$
SYNOPSIS...VJP
SHORT TERM...VJP
LONG TERM...VJP
AVIATION...KED
FIRE WEATHER...VJP
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
920 PM CDT Tue Apr 4 2023
.UPDATE...
Issued at 911 PM CDT Tue Apr 4 2023
Just expanded the wind advisory to include the northern two thirds
of the CWA. Have got some recent reports of wind damage over
Warren and Lincoln counties in the wake of some showers that have
mixed down some of the 60+ kt low level jet winds. Outside of
these showers, expect to see winds gust into the 40-50 mph range
outside of thunderstorms the rest of the night.
Britt
&&
.SHORT TERM... (Through Late Wednesday Night)
Issued at 247 PM CDT Tue Apr 4 2023
Key Messages:
1) Multiple rounds of isolated to scattered thunderstorms are
possible between late this afternoon and early tomorrow afternoon,
and some of these storms may become severe. However...
2)...The timing and coverage of thunderstorms remain somewhat
uncertain. While the potential for higher end hazards - including
large hail, strong winds, and tornadoes - will be higher with storms
during the afternoon through late evening, these storms are
likely to be more isolated and may not occur locally at all. More
widespread thunderstorms are expected very late tonight through
tomorrow morning, but these storms are less likely to be severe.
3) Redeveloping thunderstorms are likely early tomorrow afternoon in
southeast Missouri and southwest Illinois along a cold front, and a
few of these may be strong or severe.
4) Gusty winds will persist through the night, with gusts to 45 mph
possible. A Wind Advisory remains in effect for central and
northeast Missouri.
All eyes are now fixed on the potential for strong or severe
thunderstorms between this afternoon and early tomorrow afternoon as
a dynamic upper level trough approaches the area from the west.
While the core of a 90+kt southwesterly 500mb jet remains well to
the west across the central plains, strong 500mb winds of 45 to 55
kt have already spread across the region, and these winds are
expected to steadily increase over the next several hours as the
trough inches eastward. Meanwhile, a deepening surface low is in the
process of sliding northeast and into Iowa, as evidence by recent
pressure falls recorded on surface observations. Low level wind
fields are expected to respond in kind, and by early evening a 60 to
70 kt low level jet is expected to develop across much of Missouri
and southern Illinois. All of this is to say that 0-6km bulk shear
will steadily increase through the day and into the evening hours,
and will be more than sufficient to support rotating updrafts. While
lower level shear is not currently particularly strong as of 19Z,
this will change quickly during the late afternoon and evening as
the low level jet strengthens.
While the kinematic environment will certainly support severe
thunderstorm development, the thermodynamic environment is a bit
more uncertain...at least initially. The initial concern during the
afternoon is with respect to convective initiation. A substantial
capping inversion was noted in an 18Z sounding in Columbia, MO as
well as nearby ACARS soundings. However, temperatures have risen
very quickly across northern Missouri under almost full sun, which
has helped to erode this capping inversion. In fact, isolated storms
have already initiated across west-central Missouri as of 19Z,
indicating that the capping inversion has nearly eroded. On the
other hand, there is some question about the quality and depth of
low level moisture, particularly along and south of an advancing
warm front now draped across southern Iowa. High resolution models,
particularly the HRRR and RAP, have suggested that deep mixing and
shallower moisture will lead to high LCLs by mid to late afternoon,
but have also continued to initiate storms across northeast Missouri
by mid afternoon. So, while these warm temperatures and deep mixing
may help us break the cap, the higher storm bases may limit the
potential for tornadoes locally during the afternoon before they
move quickly northeast and into better moisture north of our area.
Still, considering the very steep mid and low level lapse rates, the
potential for very large hail and damaging wind gusts will be
possible for a brief period this afternoon in mainly northeast
Missouri and west central Illinois, and a tornado can`t be
completely ruled out.
Once these storms move northeast, a bit of a lull in activity is
expected as the low level jet begins to ramp up and temperatures
begin to cool. Meanwhile, a cold front will slowly advance eastward,
along with stronger upper forcing from the approaching trough.
During the evening hours, there is some potential that this
additional forcing could allow for a few strong/severe storms to
develop ahead of the cold front in the open warm sector, and if this
occurs, forecast soundings support the potential for supercells with
all possible hazards, including large hail, damaging wind gusts, and
tornadoes. As for the latter, rapidly increasing low level shear
and storm relative helicity (SRH of 300-500 m2/s2 by 00Z) support
the potential for strong tornadoes as well. Again though, coverage
is likely to be somewhat limited, and this potential remains
highly conditional. This would also likely be favored across
central Missouri and the Ozarks, along with southwest Illinois,
although confidence is somewhat low regarding the location of CI.
Finally, the aforementioned cold front will push through the area
during the overnight hours, likely beginning at around 8Z in
central/NE MO. Model guidance has steadily slowed the progression of
this front, meaning that it likely will not exit the area until
roughly 18-19Z tomorrow. This would likely lead to two things.
First, thunderstorms remain likely along the front as it moves east,
particularly north of I-70. However, instability will be waning by
this time of night, which may limit the higher end potential for
severe storms during this period. Still, there will remain plenty of
shear and at least sufficient instability that it can`t be ruled
out, with a few instances of large hail and damaging winds most
likely. A tornado or two can`t be ruled out either considering the
very strong dynamics that will remain in place through the night.
By sunrise, convective coverage is likely to wane, but heating
during the mid to late morning may allow for redeveloping
thunderstorms along and ahead of the front. While this may only pose
a threat for a brief period before the front moves off to the east,
we can`t rule out a few strong to severe thunderstorms across
southeast MO and southwest IL until about 2 PM or so.
Besides the potential for thunderstorms, southerly winds are
expected to become stronger as the pressure gradient increases this
evening and overnight, and a Wind Advisory remains in effect across
central and northeast Missouri until 7 AM. Gusts to 45 mph remain
possible in these areas regardless of the presence of thunderstorms.
BRC
.LONG TERM... (Thursday through Next Tuesday)
Issued at 247 PM CDT Tue Apr 4 2023
(Thursday - Friday)
Seasonably cool and dry conditions are forecast to end the work week
as as surface ridge moves slowly across the mid-Mississippi Valley.
High temperatures Thursday afternoon are forecast to be in the mid
to upper 50s, or about 5 degrees below normal for the date.
Some frost potential exists Thursday night due to the favorable
placement of the surface ridge and likely light/variable winds. The
one caveat is that there may still be some mid/high level cloudiness
overnight, particularly in parts of southeast Missouri and southwest
Illinois. Therefore, frost may be a bit more likely further north
where there is higher confidence in more clearing and temperatures
falling at least back into the mid 30s. There is potential for these
temperatures, if not a few degrees cooler, in parts of southeast
Missouri and southwest Illinois if the cloud cover doesn`t come to
fruition. In particular, favored valleys/low lying areas of the
eastern Ozarks which are notorious cold spots would have the
potential to have a light freeze if there is a clear sky.
A moderating trend will begin on Friday, but nothing too
substantial/rapidly changing. Low-level warm air advection looks
modest, but some weak southeasterly return flow should begin by this
time so temperatures should warm back up to near normal: into the
low to mid 60s.
(Friday Night - Tuesday)
A mostly dry weather pattern is forecast to continue this weekend
into early next week as the mid/upper level pattern will be
characterized by weak, northwesterly flow. While the center of the
surface anticyclone this weekend is likely to be in the Ohio Valley,
and toward the eastern seaboard by early next week, the western edge
of the ridge axis should still have some influences through the
weekend and potentially into early next week. By early next week WPC
500-hPa height clusters all show building ridging, either over us or
just upstream. Subsidence is likely beneath and downstream of the
mid/upper level ridge axis. This pattern is favorable not only for
dry weather, but also above normal temperatures. There is a high
confidence in above normal temperatures, but exactly how warm
depends on the speed/amplitude of the aforementioned ridge axis. At
this time, it looks more likely that it crosses the mid-Mississippi
Valley mid week. Therefore, the current thinking is that the well-
above normal temperatures (upper 70s and 80s for highs) could start
as early as Tuesday, but are even more likely just beyond. For
Sunday - Monday, high temperatures are likely to range from the
low to mid 70s, with some upper 70s possible by Tuesday afternoon.
The only chance for any measurable rainfall looks to be Sunday night
into Monday. There are signs of a northwest flow shortwave moving
through the Upper Midwest with an associated cold frontal passage.
There is a lot of spread however with the track and amplitude of
this feature, and uncertainty of moisture return ahead of any cold
frontal passage. Therefore, kept PoPs in the slight chance category
for this time frame.
Gosselin
&&
.AVIATION... (For the 00z TAFs through 00z Wednesday Evening)
Issued at 601 PM CDT Tue Apr 4 2023
One round of thunderstorms is currently exiting parts of northeast
Missouri and west-central Illinois. Subsequent rounds are possible
through the late evening and early overnight hours, but very low
confidence in coverage/timing. There is higher confidence in a
round of storms along the cold front late tonight into Wednesday
morning. These storms will move east with the frontal boundary,
reaching the central Missouri and KUIN terminals around 0900-1000
UTC, followed by the metro St. Louis sites a few hours later. Have
best confidence in higher coverage further west, so added a TEMPO
at KJEF/KCOU/KUIN for storms. After the front moves through, the
threat for showers and storms will cease, with winds veering to
the west/northwest. Strong gusts (30-40 knots) will continue
through much of the period, before beginning to wane Wednesday
afternoon.
Gosselin
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...Wind Advisory until 7 AM CDT Wednesday for Audrain MO-Boone MO-
Callaway MO-Cole MO-Franklin MO-Gasconade MO-Jefferson MO-
Knox MO-Lewis MO-Lincoln MO-Marion MO-Moniteau MO-Monroe MO-
Montgomery MO-Osage MO-Pike MO-Ralls MO-Saint Charles MO-
Saint Louis City MO-Saint Louis MO-Shelby MO-Warren MO.
IL...Wind Advisory until 7 AM CDT Wednesday for Adams IL-Bond IL-
Brown IL-Calhoun IL-Clinton IL-Fayette IL-Greene IL-Jersey
IL-Macoupin IL-Madison IL-Marion IL-Monroe IL-Montgomery IL-
Pike IL-Saint Clair IL-Washington IL.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Norman OK
1059 PM CDT Tue Apr 4 2023
...New AVIATION...
.SHORT TERM...
(This evening through Wednesday)
Issued at 405 PM CDT Tue Apr 4 2023
The dryline currently stretched across northcentral through
southwest Oklahoma and northern Texas near Lawton and Wichita Falls
is expected to retreat into western Oklahoma later this evening as
per the latest RUC run. West of the dryline, cloudcover inhibited
mixing to the mid-levels as previously expected for non-convective
severe gusts, so have cancelled the high wind warning across our
western tiered counties and replaced it with the wind advisory
currently in place. Mesonet observations still reporting 40 to 50
mph gusts across our west, so will keep the wind advisory going
through this evening, but did cancel the wind advisory across a few
of our counties in central Oklahoma which have fallen below advisory
criteria. The fire danger remains in the critical to extreme risk
categories across all but southeast Oklahoma with single digit RH
values west of the dryline. Will continue the current red flag
warning through this evening as RH`s will gradually recover and wind
gusts decrease. However, we did cancel the red flag warning across
a couple of our counties in central Oklahoma including the OKC
metro. Meanwhile east of the dryline, seeing only weak elevated
convection across southeast Oklahoma as the mid-level inversion is
keeping the unstable environment fairly capped. Latest HRRR guidance
keeping areas east of the dryline fairly convective free through the
late afternoon, although the latest two model runs have developed a
storm cell developing early this evening across southcentral
Oklahoma tracking into southeast Oklahoma. Should this cell develop,
moderate to near strong instability may be sufficient for a severe
storm with the shear sufficient to keep it organized. The primary
hazards would be large hail and damaging wind gusts under the cell,
with an additional tornado threat across southeast Oklahoma.
Expecting the upper system to start pushing the cold front into
northwest Oklahoma late this evening and start overtaking the
dryline with the surface boundary through our entire area shortly
after sunrise Wednesday. As a result, we will keep storm POPs across
southeast Oklahoma through the first half of Wednesday morning until
the surface boundary exits. Temperatures will be unseasonably
colder tonight as a Canadian-based air mass comes through behind the
cold front. All models dip the 1000-850 mb critical thickness
contour across our northern CWA with subfreezing temperatures
expected across much of northwest Oklahoma. Northwest winds will
continue to bring in dry and unseasonably cooler air through
Wednesday, mostly felt across the northern two-thirds of Oklahoma.
&&
.LONG TERM...
(Wednesday night through next Monday)
Issued at 316 PM CDT Tue Apr 4 2023
High surface pressure builds in across the Central Plains Wednesday
night as winds go light. Clear skies should result in strong
radiational cooling with another night of subfreezing temperatures
across northern through northwestern Oklahoma, while southwest flow
aloft from the trough expected to bring in cloudcover keeping the
rest of our area a bit warmer to above 40 degrees. A split-flow
upper pattern continues with a weak yet large amplitude trough in
the southerly jet across the U.S. Southwest, maintaining a weak
southwest flow downstream over the Southern Plains. A shortwave in
the flow over eastern Texas/western Louisiana interacting with low-
level moisture being transported by an easterly low-level jet may
produce sufficient ascent for widespread rain across northern Texas
on Thursday night. For now, only expecting this to possibly affect
our far southern CWA counties, so will keep low rain POPs across
western north Texas to along the Red River in southern Oklahoma
Thursday evening through Friday morning. Not expecting any storm
activity with this stable air mass.
Temperaturewise, only a gradual warming trend starting Thursday on,
with temperatures returning to mild and seasonably average by
Saturday as south winds start making a return. An upper ridge
starts building in from the west on Sunday with temperatures rising
above average. Another weak shortwave propagating through the ridge
over Kansas late Sunday may produce rain to a few weak storms across
central through northcentral Oklahoma where low POPs are in place.
Expecting the upper ridge to continue building over our area with
breezy south surface winds through early next week keeping our
warming trend going. Our western CWA may be approaching 90 degree
temperatures by Tuesday.
&&
.AVIATION...
(06Z TAFS)
Issued at 1044 PM CDT Tue Apr 4 2023
VFR conditions are expected. A cold front will shift gusty south
and southwest winds to northwest overnight. After the front,
northwest and north winds will continue gusty into the daytime
Wednesday before subsiding during the evening.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 42 58 39 63 / 20 0 0 0
Hobart OK 37 60 35 65 / 0 0 0 0
Wichita Falls TX 45 63 40 66 / 0 0 0 0
Gage OK 29 57 28 65 / 0 0 0 0
Ponca City OK 37 58 34 64 / 30 0 0 0
Durant OK 53 66 43 65 / 40 0 0 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Red Flag Warning until 11 PM CDT this evening for OKZ004>007-
009>012-014>018-021-022-033>037.
TX...Red Flag Warning until 11 PM CDT this evening for TXZ083>085-087.
&&
$$
SHORT TERM...68
LONG TERM....68
AVIATION...09
Area Forecast Discussion
National Weather Service Pendleton OR
828 PM PDT Tue Apr 4 2023
.UPDATE...Satellite imagery is showing that clouds have decreased
significantly in the last hour or two and radar is showing little
in the way of showers remaining at this time. The rest of tonight
should be quiet and dry. Have updated the forecast to have showers
ending now rather than later this evening and to reduce clouds as
most stations are reporting clear skies except for central Oregon,
which still has scattered to broken clouds. Also made some minor
wind direction and temperature changes. Otherwise, the forecast
is in good shape and no other changes were made. Forecast update
already out. Perry/83
&&
.PREV DISCUSSION... /issued 444 PM PDT Tue Apr 4 2023/
AVIATION...00Z TAFs...VFR conditions are expected for the next 24
hours. Scattered weak rain ans snow showers will continue over
the area through about 03Z but are not expected to impact TAF
sites except KRDM and KBDN, which have had snow showers in the
last few hours. Have used VCSH for those TAF sites through 03Z and
also at KALW and KPDT due to snow showers over the Blue Mountains
near those TAF sites. Skies will mostly clear overnight and then
begin to have some SCT high and mid level clouds after 18Z
tomorrow. Winds will primarily remain below 12 kts though a few
higher gusts will be possible through 03Z this evening and after
20Z tomorrow afternoon. Perry/83
PREV DISCUSSION... /issued 151 PM PDT Tue Apr 4 2023/
SHORT TERM...Today through Thursday night...Current satellite
shows a widespread cumulus field outside of the lowest elevations
of the Columbia Basin with just a few more vertically developed
cumulus evident over Wallowa County. Radar shows some light
returns over much of central and north-central Oregon with the
aforementioned activity in Wallowa County presenting the most
impressive radar signatures. That said, even these cells have
failed to produce lightning as of 1345 PDT and have only generated
a maximum of 40-45 dBZ with echo tops up to 20 kft.
12Z HREF guidance suggests rain and snow showers will taper off
this evening with the loss of daytime heating and instability.
Just a few members and latest HRRR runs hold on to some
orographically driven snow showers over the eastern mountains into
the early overnight period. Ensemble and deterministic guidance
are in excellent agreement that an upper-level ridge will
subsequently build across the forecast area tonight with drier
conditions for Wednesday as a result.
The next system is advertised to approach from the Pacific late
Wednesday afternoon and evening with warm advection aloft raising
snow levels. The forecast area will also see increasing clouds
associated with isentropic ascent, and pressure gradients will
tighten with a strengthening 850 mb jet along the foothills of the
Blue Mountains and through the Grande Ronde Valley as a result.
Additionally, isentropic analysis shows low- and mid-level descent
along the base of the northern and southern Blue Mountain
foothills Thursday morning through Thursday night, and cross
sections show a 35-45 kt jet between 850 and 750 mb. The
anticipated pattern typically favors strong winds along the base
of the Blue Mountains and through Grande Ronde Valley including
Ladd and Pyles canyons so that was a target of opportunity with
the afternoon forecast package.
Delving into probabilities, 24-hr NBM probabilities of exceedance
shed some light on the potential for wind highlights for the
aforementioned regions: a 55-85% chance of exceeding 34 kts and
40-70% chance of exceeding 41 kts exists for the northern Blue
foothills between 06Z Thursday and 06Z Friday. Moreover, there is
a 75-99% chance of exceeding 34 kts during the same time period
for the Grande Ronde Valley and Ladd and Pyles canyons, while a
50-85% chance exists to reach 41 kts in the southern Grande Ronde
Valley and Ladd and Pyles canyons. The ECMWF EFI is also
supportive of climatologically unusual winds. 00Z EFI values of
0.5-0.8 between 00Z Thursday and 00Z Saturday show decent ensemble
agreement. Examining raw ensemble wind gusts reveals a tight
grouping of 40-45 mph 6-hour maximum wind gusts for KLGD, though
there is significantly more spread at KPDT and KALW with values
ranging from roughly 35-50 mph. Care should always be taken when
interpreting raw ensemble output, but it is worth noting that the
ECMWF ensemble generally does a good job at predicting winds
through the Grande Ronde Valley. Overall, confidence is high (see
earlier probabilities) in reaching or exceeding Wind Advisory
criteria (45 mph gusts) for Ladd and Pyles canyons and the
southern Grande Ronde Valley, though there is just medium
confidence (see earlier probabilities) for much of the Blue
Mountain foothills zones and the rest of the Grande Ronde Valley.
Thus, will hold off on issuing any highlights with the afternoon
forecast.
Precipitation in the form of beneficial rain, except for snow
along the higher peaks, is forecast to spread east across the
forecast area Thursday and especially Thursday night as a cold
front approaches from the Pacific. Plunkett/86
LONG TERM...Friday through Tuesday...Prolonged SW flow aloft will
be the main story behind the long term, with much of the weather
this weekend through early next week looking to be wet as temps
slowly climb toward seasonal averages.
Ensembles generally in good agreement over this pattern, driven by
broad low pressure circulating just off the coast of BC. The warm
air advection associated with the SW flow will drive snow levels
upward through the weekend, starting at around 4-5000 ft on
Friday, right as we finally climb out of this recent cold spell,
before reaching the 6-7000 ft range by Monday into Tuesday.
Expecting primarily a rain forecast as a result, with river and
stream rises likely as rain looks to persist through much of the
forecast period across the high mountains. Main forecast challenge
stems in just how much precipitation will fall. General consensus
across guidance appears to favor more gradual showers through the
weekend into next week rather than any period of particularly
heavy shower activity. The synoptic pattern looks to be favorable
for unwavering moisture transport, with the GFS suggesting IVT in
the 300-400 kg m-1 s-1 range early next week, something the NBM
QPF guidance seems to pick up on by painting a bullseye in precip
across the crests of the eastern mountains. Will have to see how
the forecast evolves, but given current trends suggesting more
gradual shower activity, will hold off on advertising anything in
the way of significant hydro concerns.
Models have shifted more towards this SW flow pattern and away
from ridging suggested across prior runs. NBM still stubborn in
depicting robust warming over the weekend, while GEFS/EPS
ensembles are more conservative under wetter conditions via SW
flow. As a result, adjusted temperatures down a bit from NBM
guidance, but overall expecting highs to climb into the 60s
through the weekend across most of our population centers, before
possibly slackening off by the tail end of the period as some
guidance suggests the offshore low will start to push onshore,
bringing with it cooler temperatures. Regardless, overall story
for the long term is a trend towards warmer temps and wet
conditions across the forecast area, with increasing snow levels
meaning a better chance that even our high mountains see rain for
the first time in months. Evans/74
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 28 54 36 62 / 0 0 0 20
ALW 31 55 39 61 / 0 0 0 20
PSC 31 59 40 63 / 0 0 0 20
YKM 27 55 35 53 / 10 0 0 50
HRI 30 59 39 66 / 0 0 0 20
ELN 26 53 35 50 / 10 0 0 50
RDM 24 49 35 56 / 10 10 10 30
LGD 22 46 32 50 / 0 0 0 10
GCD 20 46 31 53 / 10 0 10 30
DLS 32 56 42 57 / 0 10 20 70
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
&&
$$
EVENING UPDATE...83
SHORT TERM...86
LONG TERM....74
AVIATION...83
Area Forecast Discussion
National Weather Service Pocatello ID
204 PM MDT Tue Apr 4 2023
.SHORT TERM...Tonight through Wednesday night.
Wrap around moisture still producing snow in Southeast portions
of forecast area. Massive snow amounts occurred in the Pocatello
area with 1 to 2 feet measured. Think snow will taper off this
evening with an additional half inch or so after 6 pm in the
Pocatello area and 1 to 2 inches in the southern mountains. A weak
Canadian short wave aloft will keep the chance for snow showers
going Wednesday with very light amounts expected and maybe an inch
or so in a heavier convective shower then an upper ridge begins
to slide east with drying Wednesday night. Overnight lows tonight
ranging from single digits in some mountain areas to the teens and
20s in the Snake River Plain and eastern Magic Valley. Highs
Wednesday remain extremely cold with 20s mountains to 30s valleys.
Main impact in the short term will be the winding down of the
massive snow event in Pocatello and problems with back road travel
and re-freezing after sunset of roadways which could cause some
travel problems.
GK
.LONG TERM...THURSDAY THROUGH NEXT TUESDAY...
A notable warming trend begins Thu and will continue into early next
week as broadly-speaking a weak longwave ridge tries to become
established across the west, although this ridge is looking weaker
and weaker with each new round of model guidance. An atmospheric
river of moisture impacting the PacNW will send one or more
disturbances in the height fields eastward Fri/Sat, slowing down the
warming trend a bit and resulting in some light snow showers (and
low elevation rain showers) across the region both days with a few
inches of accumulation possible in the wrn Central Mntns, but very
light amounts elsewhere (so impacts overall look very limited). We
continue to take a degree or two off of NBM high temps Sat given
this activity and widespread cloud cover. Sun may be the driest day
with high temps reaching the 50s and 60s for most lower elevation
population centers (and strong consensus in ridging on 500mb height
analysis), and while temps may try to nudge a few degrees warmer
Mon, yet another low pressure storm system may start dropping into
the nrn Rockies with rain/snow around that time (timing subject to
change in the days ahead). Watch for ripening of the snowpack at
most elevations starting this weekend, along with some runoff and
localized flooding. Big picture though, the duration and intensity
of this precip break and warmup is looking questionable/potentially
short. Perhaps winter isn`t quite gone yet? 01
&&
.AVIATION...
Impressive upslope-flow-driven snowfall continues to produce
persistent IFR to LIFR conditions at KPIH for a far longer duration
than models previously advertised. There is a hint of a back edge to
this on radar approaching from the north (anchored on a northerly
wind shift), but those winds are only making slow progress toward
the terminal, and the HRRR keeps delaying the switch and attendant
shut down of precip. Expect little to no improvement until at least
21z, and confidence on the end time is low. Eventually, we should
break out to VFR, with more isolated snow showers into this eve.
Elsewhere, hit-and-miss snow showers are possible with the heating
of the day with otherwise VFR conditions. Have covered this with
VCSH at KIDA/KDIJ, but -SHSN at KBYI/KSUN where potential coverage
looks a bit higher on the high-res CAMs. A brief drop to MVFR if not
IFR can`t be ruled out if an organized snow shower directly impacts
a terminal, but it`s nearly impossible to pin down when/where at
this juncture. Regional conditions trend less impactful tonight,
although some low stratus may try to develop into Wed AM, especially
at KPIH. Wed may feature a few more snow showers during the
afternoon, but otherwise cigs may trend SCT! 01
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Springfield MO
938 PM CDT Tue Apr 4 2023
...MESOSCALE UPDATE...
Key Messages:
1. Potential for significant severe thunderstorms including
dangerous night time tornadoes into early Wednesday morning.
2. Gusty southerly winds up to 45 mph through 1 AM.
3. Cooler and drier weather Wednesday through Friday. Monitor for
frost potential Thursday and Friday mornings.
4. Warming trend through the weekend into early next week.
.MESOSCALE DISCUSSION...
Issued at 903 PM CDT Tue Apr 4 2023
The 00Z KSGF RAOB revealed that a capping inversion has held
strong. Measured mixed-layer convective inhibition was -98 J/kg.
We had one left-moving elevated supercell develop early this
evening, but an elevated mixed layer (EML) has prevented surface-
based convection from developing.
We do not anticipate much change to capping strength through 11
PM with perhaps slow weakening after that point. Weak height
falls are just now starting to reach western Missouri. Thus,
lifting of the cap will be minimal over the next few hours. 700 mb
temperature advection remains neutral to positive. Thus, cooling
of parcels near the capping inversion is not in play (yet).
There will be slow moistening of the low-levels which would
support some weakening of the cap later tonight. We will also
have to watch for mesoscale effects around the Boston Mountains.
Localized convergence and ascent could be enough to promote
isolated initiation if the cap can weaken somewhat. We will be
conducting a 04Z balloon release to reassess the capping strength.
With all of this said, the threat for an isolated supercell or
two remains after 11 PM ahead of what will be an approaching
squall line. If a supercell can manage to develop, CAPE and shear
profiles would support significant severe potential including very
large hail and a tornado threat. This would include the potential
for a strong tornado as 0-1 km SRH values remain in the 300-400
m2/s2 range.
Our confidence is higher regarding severe potential along a cold
frontal squall line which will move from northwest to southeast
across the area late tonight and Wednesday morning. The main
potential hazard with this line of storms will be damaging wind
and hail to the size of half dollars.
There will be a mesovortex tornado threat for portions of the
line that are able to locally bow to the east or northeast and
remain in balance with the ambient low-level shear. The last few
runs of the HRRR support this potential threat.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 245 PM CDT Tue Apr 4 2023
A strong system associated with an upper level trough will impact
the central CONUS later this evening, before exiting Wednesday
morning. This system will feature strong to severe thunderstorms
capable of producing large hail, damaging wind gusts, and
tornadoes. This system will also feature non-thunderstorm gusty
southerly winds. Any flooding potential will remain low and localized
across portions of south central Missouri.
A strengthening surface low will continue to develop across
eastern Kansas and track northeast into Iowa this evening. The
area remains enveloped in the warm sector through the afternoon
with highs climbing into the upper 70s to middle 80s. Meanwhile,
low-level moisture continues to funnel into the area with strong
warm air advection occuring. Dewpoints through the event will be
in the lower to middle 60s. The remaining uncertainty is the
timing of breaking the cap associated with the elevated mixed
layer. Recent guidance continues to suggest a strong cap slowly
eroding after dark. This will be resolved through satellite,
radar, and mesoanalysis trends (refer to Mesoscale Discussion).
Nonetheless, expectations are for most of the area to remain dry
through the late afternoon and early evening before scattered
showers and thunderstorms develop through the middle to late
evening. The SPC has outlined much of the area in an Enhanced
risk, with a Moderate risk southeast of the Interstate 44 corridor
into south central Missouri. This includes hatched hail and
tornado areas, denoting the potential for significant weather.
Any activity that develops within the warm sector (ahead of the
cold front) would likely be discrete in nature. There is the
potential for a few strong tornadoes (EF2+) within any discrete
activity. Meanwhile, a potential QLCS will sweep through the area
along the cold front early Wednesday morning posing a risk for
damaging winds and tornadoes. In general, the QLCS tornadoes would
be shorter-lived and weaker than discrete supercell tornadoes.
This event will need to be monitored closely given the nocturnal
nature. Additionally details of the mesoscale environment and how
it may unfold are provided in the Mesoscale Discussion.
Meanwhile, strong southerly wind gusts will continue to ramp up
through the afternoon and evening as the pressure gradient
tightens. A Wind Advisory is in effect through tonight for areas
along and north of the Interstate 44 with wind gusts of 30 to 45
mph expected.
By Wednesday morning, activity will exit the region with the
frontal passage clearing the area by mid-morning. Expect breezy
west/northwest winds to continue behind the frontal passage.
Despite cloud cover clearing through Wednesday morning and
afternoon, cooler temperatures will filter into the area.
Afternoon highs will vary from middle 50s northwest to lower 60s
southeast. A chilly night can be expected with overnight lows in
the middle to upper 30s. Some frost potential may exist across
west central and central Missouri into Thursday morning, but
confidence remains low at this time given the dry airmass.
.LONG TERM...(Thursday through Tuesday)
Issued at 245 PM CDT Tue Apr 4 2023
Cooler and drier air persists on Thursday with afternoon highs in
the upper 50s to around 60. Yet another chilly night into Friday
morning with lows around freezing. Likewise, the dry airmass
should limit any frost potential. Meanwhile, temperatures at or
near freezing are forecast to only occur around sunrise. Continue
to monitor for potential frost or freeze.
By the weekend, a warming trend is expected in the wake of exiting
high pressure. This will set the stage for lower RH values and
increasing winds that will result in some elevated fire concerns
on Friday. Recent trends in the "green up" around the area will
begin to suppress fire weather concerns over the coming weeks.
Afternoon highs in the middle 60s on Friday.
The warming trend continues into Saturday and Sunday. A pleasant
weekend is expected with mostly dry conditions as highs climb into
the upper 60s to lower 70s. Low end precipitation chances with a
quick moving system late Sunday into Monday.
Heading into next week and beyond, the pattern favors above normal
temperatures and drier weather.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 607 PM CDT Tue Apr 4 2023
Low end VFR a to occasional MVFR ceilings will occur across the
region as scattered showers and storms impact the region this
evening. A cold front will move through the region after midnight
with MVFR to locally IFR ceilings and visibilities where storms
occur. Winds will shift from the south to the west and then
northwest by around sunrise Wednesday morning.
The SGF and BBG terminals can expect a period of low level wind
shear ahead of the cold front. Behind the front winds will begin
to drop of with 10 to 15 mph sustained.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...Wind Advisory until 1 AM CDT Wednesday for MOZ055>058-066>071-
077>081-088>091-094.
KS...Wind Advisory until 1 AM CDT Wednesday for KSZ073-097-101.
&&
$$
MESOSCALE...Schaumann
SHORT TERM...Perez
LONG TERM...Perez
AVIATION...Hatch
Area Forecast Discussion
National Weather Service Tulsa OK
741 PM CDT Tue Apr 4 2023
...New SHORT TERM...
.SHORT TERM...
(The rest of tonight)
Issued at 741 PM CDT Tue Apr 4 2023
Storm coverage over the region has been pretty limited thus far
due to lack of a focusing boundary, with the only storms being
elevated in the deep moist plume from southeast Oklahoma into
northwest Arkansas. Some additional development within the moist
plume is possible later tonight, but trends in the latest HRRR
suggest this is more likely to occur to the east of the forecast
area. The retreating dryline is colliding with the southeastward
advancing cold front over southern KS, and storms are likely to
develop soon there and spread southeast into our area with the
front thru the night. Storms along the front may become severe for
a time, but will tend to get undercut by the front, limiting the
severe threat. Another potential area for development would be
across southwest OK down into western north TX where better
moisture convergence exists with the retreating dryline. Some runs
of the HRRR have developed an isolated supercell from this area
of forcing, but thus far it hasn`t occurred. Many runs of the HRRR
and the recent Hi-Res EC continue to indicate storms will develop
from north TX up into southeast OK ahead of the front after
midnight. Any storms that can get going ahead of the front will
have the potential to produce higher-end severe weather. The
severe weather threat will come to an end Wednesday morning as the
front clears the region.
Lacy
&&
.LONG TERM...
(Wednesday through Tuesday)
Issued at 220 PM CDT Tue Apr 4 2023
Compared to today and tonight, the forecast for the remainder of
this week, through the weekend and into early next week looks
considerably less impactful. Expect below normal temperatures for
the next couple of days behind the cold front. Lower moisture and
northwesterly winds gusting around 20 mph could lead to some
localized fire weather concerns in the drought stricken areas of
northeast Oklahoma tomorrow. Warmer weather will make a return
late in the weekend and into early next week, as ridging
approaches from the west. A weak disturbance in the northwest flow
aloft prior to the ridge`s arrival could bring a few showers to
the area Sunday night, but otherwise, dry weather looks to prevail
for much of the period.
&&
.AVIATION...
(00Z TAFS)
Issued at 637 PM CDT Tue Apr 4 2023
Isolated showers and thunderstorms will be possible this evening
at the southeast Oklahoma and northwest Arkansas sites. More
numerous showers and storms will develop after midnight along and
ahead of a cold front that will sweep southeast across the area.
VFR conditions will prevail outside of thunderstorms. Gusty south
winds will shift to the northwest following the passage of the
cold front.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 45 61 37 64 / 50 0 0 0
FSM 59 68 43 65 / 80 40 0 0
MLC 52 64 41 65 / 50 0 0 0
BVO 40 60 32 64 / 60 0 0 0
FYV 51 65 36 63 / 80 40 0 0
BYV 54 65 38 60 / 70 50 0 0
MKO 50 60 39 63 / 50 0 0 0
MIO 45 57 35 60 / 70 0 0 0
F10 48 60 37 63 / 30 0 0 0
HHW 58 66 45 63 / 80 20 0 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...Wind Advisory until 1 AM CDT Wednesday for OKZ054>061-064.
AR...None.
&&
$$
SHORT TERM...30
LONG TERM....22
AVIATION...05