Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/21/23
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
913 PM CDT Mon Mar 20 2023
.UPDATE...
Issued at 901 PM CDT Mon Mar 20 2023
Not many changes to the overnight period forecast. Mid and high
level clouds are increasing from west to east, so generally
shouldn`t see too much more of a drop in temps for the rest of the
night. That said, some locations have cooled quickly this evening
prior to the onset of thicker cloud cover, so made a few
adjustments to lows. Otherwise, lead impulse tonight still looks
to bring some snow chances to north central SD between 06Z and
12Z, before the main brunt of snowfall later in the
morning/afternoon Tuesday. RAP soundings show saturation in
Lemmon around 08Z. No changes to POPs at this time.
&&
.SHORT TERM...(This Evening through Tuesday Night)
Issued at 400 PM CDT Mon Mar 20 2023
The main focus in this period will revolve around the incoming storm
system for Tuesday into Tuesday night. In the meantime, quiet
weather conditions can be expected this evening into the early
overnight. The sfc ridge will drift eastward and away from our
forecast area this evening. Clear to partly cloudy skies will give
way to increasing clouds and low overcast conditions during the
early morning hours Tuesday. Zonal flow overhead will turn more
southwesterly in response to a mid-lvl disturbance working out of
the Great Basin and into the Rockies. This wave will induce lee of
the Rockies cyclogenesis with this broad area of low pressure
progged to work out into the Central and Northern Plains Tuesday
morning. Anticipate an area of snow to develop and push through
north central SD prior to daybreak with the bulk of the precip
chances filling in across the Missouri Valley during the morning.
This will shift eastward into the James Valley and points east
during the afternoon hours and linger through the evening before
winding down in our eastern zones by late evening and early
Wednesday.
This mid-lvl compact vort looks to wind up fairly rapidly and shift
quickly across SD during the afternoon and evening before exiting
east into MN by early overnight. It will induce sfc low pressure
across southwest/south central SD by midday and is progged to track
east northeast into southeast and east central SD by late afternoon
into the evening. Winds don`t look overly impressive with this
system. Although there will be some gustiness out of the east
initially ahead of the system during the day and then northerly on
the backside of the system Tuesday night. There may be a little
enhancement of the east winds on the western slopes of the Coteau
across Marshall and Day Counties. This combined with falling snow in
the afternoon could reduce visibilities for a time. The overall
impacts of blowing snow look to be more muted and brief with
generally the worst of the conditions occurring during the late
afternoon into the first half of the evening. The snowfall could be
briefly heavy at times, especially across northern zones between the
Missouri and James Valley`s. HREF pings those locales with 1 inch/hr
snowfall rates for a short time during the late afternoon and early
evening before shifting quickly north into ND. Accumulations will
generally fall into the 1-4 inch category across the CWA with the
least amounts south and the highest amounts along and north of the
US Highway 12 corridor. There may be a locale or two closer to 5
inches right along the ND/SD border. GEFS/GEPS/EC plumes for
QPF/snow all seem reasonably agreed upon these with respect to this
system with
The other caveat that this system looks to deliver is some mixed
precip. BUFKIT soundings along with EC meteograms for locales along
our southern zones support pockets or areas of freezing precip from
around the I-90 corridor in our south northeastward toward the
Miller area and then over toward the Watertown area. On the backside
of the system, BUFKIT soundings indicate a loss of ice aloft toward
the end of the system tomorrow evening as far west as the
Aberdeen/Redfield areas. Not so confident in this scenario playing
out at this time due to uncertainty of where precip will be falling
then. It should be brief in nature however if it does materialize.
Temperatures through the entire period will continue to remain well
below normal. Lows in the teens with highs in the 20s and 30s looks
to be a sure thing going into mid-week.
.LONG TERM...(Wednesday through Monday)
Issued at 400 PM CDT Mon Mar 20 2023
By 12Z Wednesday the area of low pressure will become nearly stacked
from the surface through 500mb over northeastern Minnesota. A dry
surface ridge of high pressure will bring some pockets of clearing
before high clouds return from the southwest. The cold air
advection, lingering longer over our eastern counties, should keep
high temperatures near or below freezing Wednesday afternoon.
While the next surface low will likely track west to east across KS
Wednesday night into early Thursday, the 500mb trough and 700mb low
will shift into western SD by daybreak Thursday. Light snow will
overspread the region, with the main focus looking to be near and
south of the I-90 corridor. There significant differences between
the model solutions, with the 00Z run of the operational GFS
indicating the potential for heavy banded snow over portions of NE
and southern SD. We`ll continue to monitor for a potential northern
shift, and where winter weather headlines may be needed. At this
point, we`re going with little to no snowfall for our northeast most
counties. The 500mb low looks to exit Thursday night. However, the
series of upper level waves will continue to swing across the
Northern Plains through the rest of the forecast period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday Evening)
Issued at 627 PM CDT Mon Mar 20 2023
Terminals KABR,KATY,KPIR,KMBG
VFR conditions will prevail early on in the TAF period, although
expect MVFR/IFR CIGs to overspread the region late tonight into
Tuesday morning as a storm system approaches. -SN/SN is also
forecast to spread into the area during the day Tuesday, with
MVFR/IFR VSBY.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Winter Weather Advisory from 1 PM Tuesday to 1 AM CDT Wednesday
for SDZ005>008-010-011.
Winter Weather Advisory from 1 AM CDT /midnight MDT/ to 7 PM CDT
/6 PM MDT/ Tuesday for SDZ003-004-009.
MN...Winter Weather Advisory from 1 PM Tuesday to 1 AM CDT Wednesday
for MNZ039.
&&
$$
UPDATE...TMT
SHORT TERM...Vipond
LONG TERM...KF
AVIATION...TMT
Area Forecast Discussion...Updated
National Weather Service Billings MT
953 PM MDT Mon Mar 20 2023
.UPDATE...
The 00Z runs for the models are backing off on the fog potential
in southeast Montana. The HRRR and the NAM do still have some
lower visibility, but this looks like it will more associated with
some snow vs fog. There could still be some low clouds, but the
surface winds are also expected to be breezy through much of the
night, so the mixing will likely keep things as stratus. Reimer
&&
.DISCUSSION...
Tonight through Wednesday Night...
Satellite imagery indicated a weakening ridge over southeast
Montana with SW flow moving into the south central mountains
due to a negative tilt trough moving through Oregon. Clouds were
increasing across our region with some light snow on radar over
the Absaroka/Beartooth Ranges and nearby foothills.
That upper shortwave trough will work into Idaho this evening and
cut eastward across northern Wyoming late tonight through Tuesday.
So we are looking for increasing snow in the high country this
afternoon into the evening while easterly upslope/overrunning and
some dynamic lift affect our western foothills and nearby plains.
Instability is such that we may see some snow squally type bands
in our west this evening. As shortwave progresses east Tuesday it
will spread lift and instability east with westerly flow kicking
in behind it. Dynamics affect mainly the southern portions of our
CWA Tuesday including the Big Horns region and SE MT. In the
meantime...models develop some light snow and fog over eastern
Montana tonight in the isentropic ascent area ahead of the
shortwave...but this should not amount to much.
Due to the nature of the instability and track of associated 700mb
low, we could see a few areas in west get some intense snow shower
bands this evening followed by light snow then west winds kicking
in behind the shortwave creating a some lulls in the snow by
Tuesday morning. Overall snowfall amounts tonight through early
Tuesday will range from about 1-3" in the west and less than an
inch in the central zones. Very tricky to determine which areas
may see impacts from snow and slick roads...models take road
surfaces to freezing by mid-late evening in the west where the
most snow may occur. So the Tuesday morning commute may be slick
in these areas. Despite below normal confidence in placement of
accumulating snow, we will issue a Winter Weather Advisory due to
this potential hazard across the western foothills and nearby
plains this evening through noon Tuesday. (Paradise Valley,
Livingston, Northern Park, Beartooth Foothills, Melville
Foothills, Northern SweetGrass)
We may need winter weather advisories for SHeridan, Wy to SE MT
Tuesday, but will let future shifts get a closer look. Most of
this snow may occur during the day which minimizes impacts to
travel. However, SE MT (Carter, Powder River) may see 1-3" of
snowfall at least on grassy surfaces.
Tuesday night should see mostly dry conditions behind the
shortwave. However, another un-organized short wave tracks through
the central Rockies Wednesday. Currently, ensembles keep most of
the energy south of our CWA, but precipitation does spread into
our southern border areas including the Absaroka/Beartooths and
Big Horn Mtns where some light accumulations area possible. As the
upper shortwave energy exits the mountains Wednesday night into
eastern Wyoming there is some decent lift that develops over the
SE corner of Montana where a couple of inches of snow is possible
(mainly Carter/Powder River counties). However, any slight
deviation in the track of the upper shortwave could easily change
the placement of accumulating snow.
Look for highs Tue/Wed mainly in the upper 20s and 30s with
perhaps a few locations reaching near 40 on Wednesday in the west.
Overnight lows will be in the upper teens and 20s. BT
Thursday through Monday...
Thursday, clusters show the region in a strange split flow
pattern with below average heights. Behind this split flow there
is good agreement a trough will enter the region Friday into
Saturday. Early next week another trough looks to make its way
into the region. This unsettled pattern will bring consistent low
precip chances. The best chance for precipitation looks to be
Friday into Saturday. Even this looks to be light with NBM giving
non-mountainous regions <20% chance for 1/4 inch of
precipitation. NBM chances for 48 hour snowfall for this time sit
at <30% for the southern CWA. NBM chances for the Bighorns and
Absaroka/Beartooth mountains are currently >50% for 4 inches.
Before the trough moves in, temperatures will be near normal
(40F-50F) for Thursday and Friday. After that the general
troughing pattern will bring below average temperatures for
Saturday, Sunday, Monday with temperatures generally 5-10 degrees
colder.
&&
.AVIATION...
Conditions will continue to deteriorate this evening across the
region to MVFR/IFR/LIFR from low ceilings and snow/mist. These
conditions will expand eastward tonight to impact much of the
area. Mountains will be obscured tonight. LT/Arends
&&
.PRELIMINARY POINT TEMP/POPS...
Tue Wed Thu Fri Sat Sun Mon
-----------------------------------------------------------
BIL 025/037 023/040 022/051 031/048 028/041 023/040 022/046
54/S 03/S 31/B 13/O 43/S 22/S 11/B
LVM 026/038 022/036 019/046 026/039 020/035 017/037 017/042
84/S 03/S 31/B 25/S 33/S 32/S 11/B
HDN 022/037 018/040 018/052 026/051 026/042 021/041 019/047
43/S 03/S 31/B 14/R 53/S 32/S 21/B
MLS 022/030 017/035 017/045 026/048 028/038 022/036 020/043
45/S 01/B 31/B 01/B 22/S 11/E 11/B
4BQ 026/033 020/037 020/046 026/051 027/039 023/037 022/044
47/S 04/S 41/B 02/R 42/S 21/E 11/B
BHK 015/027 011/030 012/039 019/043 020/033 016/032 014/038
44/S 01/B 31/B 00/U 22/S 21/E 11/B
SHR 020/033 015/034 017/042 020/044 020/035 014/034 014/040
57/S 06/S 41/B 04/S 54/S 33/S 21/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory in effect until noon MDT Tuesday FOR
ZONES 40-64>66-141-172.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service Corpus Christi TX
707 PM CDT Mon Mar 20 2023
...New AVIATION...
.SHORT TERM...
(Tonight through Tuesday night)
Issued at 359 PM CDT Mon Mar 20 2023
Deterministic runs maintain a quasi-stationary upper pattern
during the period, except for a high amplitude upper level
disturbance predicted to enter western CONUS Tuesday. In response
to the quasi-zonal flow, expect deepening low MSLP over the Lee of
the Rockies/southern Plains during the period, as predicted. As a
result, onshore flow will increase. PWAT values slowly rising
today (LAPS analyses) and expect PWAT values slightly above normal
Tuesday/Tuesday night. Although patchy light rain/isolated
showers may occur tonight, expect the best chance for
precipitation to occur Tuesday, considering isentropic lift/low
condensation pressure deficits at 300K. Patchy stratus-lowering
mist/fog may occur over portions of the CWA 09-13z Tuesday, yet
anticipate mainly MVFR visibilities. Will maintain the Moderate
risk of rip currents for tonight.
&&
.LONG TERM...
(Wednesday through next Sunday)
Issued at 359 PM CDT Mon Mar 20 2023
Key Messages:
-Windy conditions develop Thursday into Friday ahead of a cold front
-Slight chance of thunderstorms and chance of showers late Thursday
night into Friday morning
A dry weather pattern will continue Wednesday into Thursday as mid-
upper level high pressure sits over the Gulf of Mexico. An incoming
mid-upper level trough will nudge the high pressure to the east, and
give us our next shot at precipitation as it ejects a cold front
into the area.
Windy conditions will develop as high pressure remains to our east
and the trough approaches from the west, causing the pressure
gradient to tighten. Winds may reach advisory criteria briefly
during Thursday afternoon.
This next cold front is not expected to be much of a rain maker.
Timing of rain chances appear to be during the overnight hours
Thursday into Friday. Current ensemble probabilities show around a
20-30% chance of QPF greater than 0.1" for the northern tier
counties. The chances of greater that 0.1" of rainfall increases
towards the northern Coastal Bend (30-50%), with the highest
probabilities in the Victoria Crossroads (60-90%). Probabilities for
accumulations of 0.5" or greater were zero area wide. Did not
deviate from previous forecaster`s predictions about thunderstorms
with this front. Model guidance still suggests SBCAPE will be
limited; however WAA and positive vorticity in the 850mb layer could
lead to elevated thunderstorms. PWAT values will be over 1.5" (near
99th percentile) during this time, and will further support rain
chances. Temperatures will cool down briefly Friday night.
Warm temperatures quickly recover going into the weekend as quasi-
zonal flow takes over. Low level moisture will increase through the
weekend, with PWATs returning to around 1.5" levels on Sunday. Could
see some streamer showers during that time.
Timing of the next front is still an issue between models. The ECMWF
brings the front through late monday night, while the Canadian and
GFS bring it through early Tuesday morning. In any case, went with
NBM as far as PoPs are concerned.
&&
.AVIATION...
(00Z TAFS)
Issued at 707 PM CDT Mon Mar 20 2023
MVFR ceilings will continue to be prevalent across south Texas
into the early overnight period. Southerly low level flow will
increase to 30-35 knots overnight and continue over the coastal
plains through the day Tuesday. SREF probabilities and HRRR model
show ceilings will lower to IFR over the Brush Country around 08Z
and to the inland Coastal Bend around daybreak Tuesday. Fog will
also develop over the northern Brush Country from 10-14Z with MVFR
vsbys. Slow improvement of ceilings to MVFR is expected over the
Brush Country, while MVFR ceilings persist through the afternoon
for the coastal plains. Clouds will scatter out/VFR by the mid
afternoon over the western Brush Country. Gusty south to southeast
winds are expected on Tuesday for the coastal plains with gusts
to over 30 knots at CRP in the afternoon.
&&
.MARINE...
Issued at 359 PM CDT Mon Mar 20 2023
In response to deepening low pressure upstream, expect increasing
onshore flow during the period. Small Craft Advisory conditions
are expected to commence tonight and continue at least through
Tuesday night (based on deterministic Global, Mesoscale, and CAM
output, expect 20-25kt wind to develop over the coastal waters
tonight, yet fall to 15-20kt over the nearshore waters Tuesday.
However, the NBM suggests 5-7ft seas over the nearshore waters by
Tuesday afternoon, and high seas are expected to continue through
Tuesday night. Thus, decided to hoist a continuous SCA for 00z
Tuesday to 05z Wednesday, after coordinating with WFOs BRO/HGX).
However, anticipate only 15-20kt over the bays, based in part on
cool SST values.
Moderate to strong onshore flow of 15 to 25 knots and elevated seas
will then continue through Thursday night with periods of Small
Craft Advisory conditions possible. Chances of showers and
thunderstorms increase on Friday as a cold front moves offshore
during the day. Brief offshore flow can be expected Friday night
with onshore flow returning by Saturday afternoon.
&&
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 61 75 68 81 / 20 20 10 0
Victoria 57 73 66 80 / 20 20 10 0
Laredo 60 85 68 90 / 0 10 0 0
Alice 57 77 65 85 / 10 20 10 0
Rockport 61 72 67 77 / 20 20 20 0
Cotulla 58 83 68 90 / 10 10 0 0
Kingsville 60 76 67 83 / 10 20 10 0
Navy Corpus 63 73 69 78 / 20 20 10 0
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory until midnight CDT Tuesday night for GMZ250-
255-270-275.
&&
$$
SHORT TERM...WC
LONG TERM....HA
AVIATION...TMT/89
Area Forecast Discussion
National Weather Service Cheyenne WY
930 PM MDT Mon Mar 20 2023
.SHORT TERM...(This evening through Tuesday)
Issued at 137 PM MDT Mon Mar 20 2023
High pressure remains locked in across the southeast CONUS, as a
shortwave continues digging southward into Colorado. Current
observations have seen some gusty winds across the I-80 corridor,
and snow shower actively moving from west to east near Laramie and
further eastward into Wheatland. All in all, no major squalls
developed yet today, with only some minor banded snow that
dropped visibilities near the terminals to around 1sm and winds
remaining under criteria. Main concern tonight includes the
continued chance for snow squalls through sunset. HiRes model
guidance is still pushing upwards to 200 to 350 J/kg of CAPE along
the I-25 corridor from Cheyenne to Douglas and the HRRR hinting
at a line of precipitation developing along the boundary as it
pushes to the northeast along the steering flow. 700mb winds also
remain elevated with some gusts near 40 knots, which support snow
squall development. However, confidence remains low at this time
for anything noteworthy. Nevertheless, with the HRRR maintaining
the development of the snow band later tonight, went ahead and
added some POPs to the forecast to account for this model solution
and will need to monitor just after midnight for any snow squall
potentials.
Current observations have seen intermittent snow, primarily from the
banded snow that has moved across the zones, with better coverage
developing overnight. Snow will begin to taper off during the
daytime hours on Tuesday, with a shortwave ridge moving across the
CWA, which will briefly increase daytime highs to the low-40s to low-
50s for most areas east of I-25 and bringing us into near-normal
temperatures. Next potential wind threat in the next 24 hours
include a chance for strong wind across the wind prone areas on I-25
and I-80. Wind threat still appears marginal, with in-house model
guidance keeping the wind gusts just under 50 knots and CAG-CPR
height gradients dropping from 60 meters with earlier model runs
to around 20+ meters. At this time, decided to hold off on
upgrading any watches to warnings and will let the evening crew
take another look.
.LONG TERM...(Wednesday through Monday)
Issued at 137 PM MDT Mon Mar 20 2023
The main concern with this portion of the forecast is the timing
of the various shortwaves moving through the area during the
remainder of the week.
A very active pattern will be setting up over the area through the
week. The models are showing numerous shortwaves pushing through
the jet. The initial shortwave is progged to move towards the
forecast area on Wednesday on the left exit region of the upper
level jet. It appears like the best lift will be focused over the
Sierra Madre range once again with some shadowing possible over
the Snowy Range, due to strong southwest flow. The other concern
to be on the lookout for is a possible stationary boundary
setting up somewhere between Gillette and Douglas. As the
shortwave ejects into the northern Plains on Wednesday into
Wednesday night it may set the stage for some frontogenesis near
the frontal boundary which could affect Converse and Niobrara
counties Wednesday afternoon into Wednesday night. Not confident
on how this will evolve, but certainly something we will need to
keep an eye on.
The next concern is the wind after the passage of the shortwave
Wednesday night into Thursday. The local in-house models are
showing another favorable period for some strong winds mainly for
the wind prone areas. The GFS is the only model that is trending
to keeping a closed surface low tracking through the northern
Wyoming while the GEFS/EPS ensembles and the ECMWF turns this
feature into more of an open wave. We are leaning towards more
towards an open wave solution for now, which may limit the high
wind potential a bit, but it is still certainly something we will
need to see how this pans out. The GFS is also showing some signs
of some elevated instability in the Nebraska panhandle Wednesday
evening before the front moves through Wednesday night which may
result in some rain/snow showers.
The remainder of the week will continue to be quite active with
another disturbance moving through the area on Saturday. This may
bring our next chance of rain/snow showers. Regardless, the
pattern will continue to be quite cool with highs struggling to
get out of the 30s and 40s.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 927 PM MDT Mon Mar 20 2023
A round of -SHSN will move from southwest to northeast during the
overnight to early morning hours. This will cause nearly all
terminals to transition from VFR to low-end MVFR/IFR as CIGs and
VIS decrease between approximately 6Z-12Z Tuesday. SE WY terminals
will see the VIS and CIGs reductions 7Z-10Z, and the NE Panhandle
terminals will experience -SHSN between approximately 10Z-13Z
Tuesday morning. Wind gusts are expected to pick up after
daybreak for all terminals, with gusts of 30-35 kts likely after
18Z Tuesday. Winds/gusts should begin to taper off by 0Z
Wednesday for all terminals.
&&
.FIRE WEATHER...
Issued at 137 PM MDT Mon Mar 20 2023
Fire weather concerns will remain minimal throughout the week due to
multiple rounds of precipitation. Rain and snow showers can be
expected Monday through Thursday, with snow accumulations possible.
High winds are possible for the wind prone areas of southeast Wyoming
Tuesday and Wednesday.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Watch from 3 AM MDT Tuesday through Tuesday afternoon
for WYZ106-107-110.
Winter Weather Advisory until 6 PM MDT Thursday for WYZ112-114.
NE...None.
&&
$$
SHORT TERM...MRD
LONG TERM...REC
AVIATION...BW
FIRE WEATHER...SF
Area Forecast Discussion
National Weather Service Wichita KS
712 PM CDT Mon Mar 20 2023
...Updated Aviation Discussion...
.SHORT TERM...(This evening through Thursday night)
Issued at 224 PM CDT Mon Mar 20 2023
Bottom line up front: breezy this evening, with increasing shower
chances across southern and southeast KS late this evening and
tonight. Above normal temperatures for Tue and Wed. shower chances
return late in the week.
A tight pressure gradient has led to gusty winds over the area for
the afternoon hours. winds are currently bumping up against wind
advisory criteria, so will keep the wind advisory going until 00z.
think the winds will relax some this evening, as the winds decouple
and south warm advection increases. Latest RAP suggests that this
warm advection/moisture advection will increase late this evening
over southern KS, for a chance of showers after 03z, with this
moisture transport and shower chances increasing for areas east of I-
135 for the rest of the overnight hours into early on Tue. Even
seeing some elevated instability around 500-800 J/KG, so could see a
few rumbles of thunder.
This moisture transport continues to veer to the east over the Flint
Hills and southeast KS for the morning hours on Tue. Areas along and
east of the KS Turnpike have the best chance of seeing appreciable
rainfall amounts, of a quarter to a half an inch. Expect most of
this shower chance to move out of SE KS by around noon.
A weak surface trough will continue meander across KS for the rest
of Tue into Wed, with SW flow creating nice downslope conditions for
most locations with temperatures climbing into the lower 70s on Tue
and into the upper 70s across southern KS for Wed, due to
compressional heating south of the trough. Could see breezy
conditions again on Wed, which will probably lead to another
elevated grassland fire risk.
The surface trough pushes east of the area for Wed night, with a
cold frontal boundary "backdooring" into the area late Wed or early
on Thu. A shortwave is expected to move east across the area on Thu,
which will lead to increasing chances of showers for initially SE
KS, as the cold front stalls over SE KS. But overrunning over the
top of the stalled boundary may lead to shower chances increasing
for most of southern KS by Thu evening and Thu night.
Ketcham
.LONG TERM...(Friday through Monday)
Issued at 224 PM CDT Mon Mar 20 2023
Lots of uncertainty on how the end of the week will play out, as the
GFS shows a quick hitting system moving across NEB, which may lead
to a shower chance across northern and central KS by Sat, but the
ECMWF is weaker and further north with this system, which may lead
to the shower chance staying over NEB and the Dakotas.
Ketcham
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 709 PM CDT Mon Mar 20 2023
Areas of rain showers will increase overnight and persist through
Tuesday morning across generally the eastern half of Kansas, as a
pair of shortwaves approach from the west. Can`t rule out a few
rumbles of thunder, but meager instability should keep it mostly
showers. Also, MVFR ceilings will increase from the south late
tonight and persist into Tuesday morning, in response to low-
level moisture advection. Could see some IFR ceilings for a time
Tuesday morning, but for now kept things MVFR.
&&
.FIRE WEATHER...
Issued at 224 PM CDT Mon Mar 20 2023
Very high fire danger is expected area-wide until the early
evening hours. Southerly winds are forecast to continue at around 20
to 30 mph, gusting up to 35 MPH. A modest increase in moisture
advection will lead to the grassland fire index decreasing late
this evening even with the gusty winds.
The fire weather concerns continue through midweek as gusty winds
overlap with warm temperatures, and reduced relative humidity.
Ketcham
&&
.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT 42 70 51 79 / 40 10 0 0
Hutchinson 41 72 46 77 / 40 10 0 0
Newton 41 68 50 77 / 50 10 10 0
ElDorado 42 65 53 78 / 60 30 10 0
Winfield-KWLD 43 68 54 80 / 60 30 0 0
Russell 40 70 37 72 / 20 0 0 0
Great Bend 41 71 40 77 / 20 0 0 0
Salina 41 71 43 73 / 50 10 10 0
McPherson 41 70 46 75 / 40 10 0 0
Coffeyville 42 59 53 77 / 60 70 10 0
Chanute 41 58 52 77 / 70 70 20 0
Iola 41 57 51 77 / 70 70 20 0
Parsons-KPPF 42 58 53 77 / 60 70 10 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
SHORT TERM...Ketcham
LONG TERM...Ketcham
AVIATION...ADK
FIRE WEATHER...Ketcham
Area Forecast Discussion
National Weather Service North Platte NE
605 PM CDT Mon Mar 20 2023
...Aviation discussion...
.SYNOPSIS...
Issued at 420 PM CDT Mon Mar 20 2023
Key Messages:
- A warm front brings the threat of freezing rain and wintry mix
tonight into tomorrow, which could result in hazardous conditions.
Winter Weather Advisory in effect for much of the area.
- The next system arrives Wednesday into Thursday, which could bring
light accumulations of snow to northern Nebraska.
- Temperatures remain near or below normal for the next several
days. (normal highs are generally in the mid 50s)
Synopsis:
Western Nebraska remains in quasi-zonal flow aloft as the primary
northern stream lies near the Canadian border and the subtropical
jet cuts across the Desert Southwest. A week upper low is moving
into the Inland Northwest, while an H7 low near the Black Hills
drags an elevated front or shortwave near northern CWA. At the
surface, a quasi-stationary front cuts right across the Sandhills,
roughly from KCDR to KLBF, then back toward KOMA. Temperatures as of
20z remain near freezing in the far north and have risen into the
mid 50s near and south of the front.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 420 PM CDT Mon Mar 20 2023
This evening and tonight... East/southeast upslope low level flow
continues on both sides of the surface boundary, resulting in modest
moisture advection. Expect surface dew points to rise from the lower
20s into the upper 20s by sunrise. Isentropic upglide is prevalent
at 280-290K along the front, which coincides with the increasing
moisture. Guidance suggests the boundary to lift north as a warm
front, anchored by the surface low near the Black Hills. Expect some
precip development as the low levels moisten and forcing increases,
although fog and/or drizzle may precede the activity. Forecast
soundings suggest a very shallow saturated layer to start before
further saturation occurs after sunrise. Capped PoP to schc or low
end chc through 12z. Did not mention fog in the official forecast
due to a brief window for optimal development and lower confidence
for placement. For min temps, stuck with the general model blend
which also lines up with the middle of the NBM envelope. Forecast
values range from the lower 20s in the far north to lower 30s far
southwest.
Tomorrow... A rather complex scenario is in store as the warm front
lifts into South Dakota during the morning, and a cold front is
quick on its heels, crossing the Sandhills during the afternoon.
Meanwhile, a mid-level shortwave brushes the northern Sandhills
later in the day. Increased PoP a bit along the Hwy 83 corridor to
account for the warm front passage and far north central for both
fronts and shortwave. Trended the PoP forecast toward the more
aggressive solutions (HREF, NAM), as there is quite a discrepancy in
coverage and overall potential for precip amongst the 20/12z model
suite. For instance, GFS and HRRR suggest very little recordable
moisture and keep it confined to far northern Neb. Did not feel
comfortable with the "optimistic" solutions due to the environmental
setup of a warm front passage in the wintertime. The current
forecast favors a rather quick-hitting round of precip during the
morning for western Neb and perhaps some lingering showers in the
afternoon for far north central. As for ptype, things could be a
mess. The thermal profile changes from very shallow and cold
saturation (freezing drizzle), to deeper moisture but with a warm
nose and cold surface (freezing rain or wintry mix), to deeper
moisture but entirely cold profile (snow), to drier but slightly
warmer air (rain/snow mix). Essentially, nearly all types are in
play for the heart of the forecast area from 6am-noon. With that in
mind, issued a Winter Weather Advisory. Do not expect much snow
accumulation due to marginal ground temps and very low SLR`s (1-
4:1), but am concerned about the potential for a glaze of ice. As
for the cold front, temp advection is delayed as an H85 thermal
ridge actually sets up on the leading edge. In all likelihood, the
cool front may merely act as a dry line. With negligible 24 hr H85
temp changes, highs should be fairly similar or slightly milder than
today. Winds may also gust over 30 mph behind the front in the
panhandle and northern Sandhills. When combined with the influx of
drier air, fire weather conditions may be locally elevated in the
panhandle.
Tomorrow night... A brief lull in activity is anticipated as the
cool front exits the CWA, high pressure settles in at the surface,
and flow aloft transitions to southwesterly. Weak cool air advection
begins with northerly flow at H85. Forecast lows range from the
upper teens far north to upper 20s far southwest.
.LONG TERM...(Wednesday through Monday)
Issued at 420 PM CDT Mon Mar 20 2023
The main forecast beyond tomorrow revolves around the next storm
system slated to affect western and north central Nebraska Wednesday
into Thursday. A lee side surface low spins up in eastern Colorado
later Wed and rides the NE/KS border through early Thu. The subtle
upper low approaches from the north during the same time, and the
main H3 jet noses right into the CWA. The jet may be particularly
intense with a streak of 140 kts. Currently, the most favorable
location for persistent precipitation and cold enough temps for snow
is Hwy 2 and north. The greatest potential for accumulating snow,
mainly on the order of 1 to 3 inches, lies closer to Hwy 20. Across
southwest Neb, the air may stay warm enough to keep precip as
rain/snow mix or all rain. The synoptic pattern remains unsettled
heading into the weekend as well, with low end PoP to round out the
forecast period. Highs should stay in the 40s or 50s the next
several days (or 30s far north), while lows stay in the 20s to
around 30.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 605 PM CDT Mon Mar 20 2023
VFR early, trending to IFR/LIFR towards daybreak with icing
possible.
Satellite and surface observations indicate generally mid/high clouds
across central and western Nebraska early this evening, and expect
this will remain the case until low clouds surge in from the east
late tonight. Expect IFR/LIFR due to low cigs and vsbys, with a
wintry mix of precipitation and a glaze of ice on aircraft surfaces
from just before daybreak through Tuesday morning. While precipitation
will diminish by early Tuesday afternoon, Do not expect significant
improvement in flight conditions until late Tuesday morning with
VFR conditions becoming established once again toward the end of
the valid period.
Winds may be a bit gusty at issuance but expect laminar conditions
to become established early with a light easterly surface wind
thorugh tonight. Winds veer around to the west late in the period
but look to remain 10kt or less.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 4 AM CDT /3 AM MDT/ to 4 PM CDT /3
PM MDT/ Tuesday for NEZ005-006-008-009-023>026-035>037-057-059-
094.
&&
$$
SYNOPSIS...Snively
SHORT TERM...Snively
LONG TERM...Snively
AVIATION...MBS
Area Forecast Discussion
National Weather Service San Francisco Bay Area
610 PM PDT Mon Mar 20 2023
.SYNOPSIS...High winds and widespread rainfall tomorrow, with High
Wind Warnings out for the Monterey and San benito mountains and Wind
Advisories from the San Francisco Bay Area to the Monterey County
coast. Scattered showers persist into Wednesday and unsettled
pattern continues into next week. Monitoring potential for
unseasonably cold temperatures next weekend, and a new storm system
the beginning of next week.
&&
.DISCUSSION...as of 03:11 PM PDT Monday...A break in the rain for the
rest of today as winds remain light and mainly clear, with highs in
the lower elevations in the mid 50s to low 60s, and into the mid 40s
to low 50s for the higher elevations.
A storm system is approaching California and will impact the SF Bay
Area and Central Coast starting early on Tuesday. While the system
is associated with an atmospheric river approaching the state, the
main moisture tap will be directed to our south in southern
California and Baja California. For our area, winds will be the main
issue, with the most impactful gusts Tuesday morning into the
afternoon. A High Wind Warning is in effect from 7 AM to 9 PM
Tuesday in the mountains of Monterey and San Benito Counties, where
southerly gusts of over 70 mph are expected. Elsewhere, a Wind
Advisory is in effect for the East and South Bay, the San Mateo
Peninsula, and the lower elevations of the Central Coast, also from
7 AM to 9 PM Tuesday, with southerly wind gusts of up to 40-50 mph
are expected, with more intense gusts in the higher elevations. The
North Bay should see gusts of up to 20-25 mph. Much of the
uncertainty in the strength of the wind gusts is in the wider SF Bay
region, as models are still having difficulty on the location of a
surface low that`s expected to enhance wind gusts. The global GFS
and European models are bringing the low to a stall off the coast of
the San Mateo Peninsula, while the higher resolution HRRR and NAM
are bringing the low onshore along the Central Coast. We will
continue to closely monitor the surface low and its evolution as the
impact comes closer.
Rainfall will be a secondary impact in our area, although expected
totals are not as high as those in southern California. here too,
the most intense rain is expected Tuesday morning and afternoon. The
lower elevations of the North Bay, SF Bay Area, and Central Coast
are currently forecast to see three-quarters of an inch to one inch
of rain, save for the most northern parts of Sonoma County where
rain totals go down to half an inch. The Central Coast mountains
remain the regional epicenter of rain impacts, with rain totals in
the Santa Lucia mountains expected to range from 2 to 3 inches, and
the Santa Cruz and interior Monterey and San Benito mountains
expected to reach 1.5 to 2.5 inches of rain. Higher elevations in
the Bay Area should expect 1 to 2 inches of rain. A slight chance of
thunderstorms exists into the post-frontal environment on Tuesday
evening, especially on the Central Coast.
The combination of continued rain, high winds, and saturated soils
poses a set of hazards that, at this point, are now familiar to many
in our region. The rain brings a chance for minor urban and small
stream flooding, and with soils already so saturated from the storms
earlier this month, the risk of shallow landslides continue. High
wind gusts will also result in downed trees and power lines,
possibly resulting in isolated power outages, and difficult driving
for high profile vehicles. If your area is prone to power outages,
use today to prepare, and remember to "turn around, don`t drown"
when encountering a flooded roadway or path.
The heaviest rain diminishes Tuesday evening, with post frontal
showers expected through Wednesday. Current predictions leave
Thursday to Saturday relatively dry with very little, if any, rain.
Any rain that falls in the next three days is not expected to rise
past half an inch in total. All attention then focuses on the
beginning of the next week, where early model indications suggest
another system coming through, the exact details of which won`t
become clear until later in the week. In addition, low temperatures
next weekend are expected to dip into unseasonably cold readings,
with lows in the low to mid 30s expected Saturday and Sunday morning
in the interior valleys, including the Sonoma, Napa, and Salinas
Valleys, and into the higher elevations. With the occurrence of "bud
break" in the North Bay vineyards, and the Spring harvest
approaching, this is a particularly sensitive time for the
agricultural industries. More details on the low temperatures and
the system next week will come as the forecast gets refined later in
the week.
&&
.AVIATION...as of 05:30 PM PDT Monday..For the 00z TAFs..VFR with
breezy onshore flow continuing through the evening. By early
Tuesday morning, E/SE winds begin to increase as a strong surface
low approaches the coastline of Central CA. This low pressure
system will also bring moderate to heavy rain starting early
morning lasting through the afternoon with scattered showers
continuing through the evening. MVFR conditions prevail during
this time. As the low approaches and moves inland, southerly winds
will increase through the morning and afternoon. Strong gusts of
35 to 40 knots possible across the region, primarily south of the
Golden Gate. Winds begin to diminish by the end of the TAF period.
Vicinity of KSFO...VFR continues with breezy northwest winds
diminishing tonight. Rain expected to arrive at the terminal
around 12Z with high confidence of MVFR conditions as the rain
passes through. Winds will turn easterly early morning Tuesday and
increase as low approaches. Winds shift SE as low moves inland and
eventually out of the SSE/S. Wind gusts become strongest between
20z and 04z with gusts up to 35 knots (but potentially higher
depending where low sets up and will continue to monitor).
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR with breezy onshore winds that are
slowly diminishing. SE winds increase starting early this morning
around 09z. Strong SE winds will continue beyond 09z and increase
further during the afternoon with gusts around 35 knots with up
to 40 knots possible. Moderate, to at times of heavy, rain will
accompany the increased winds.
&&
.MARINE...as of 03:11 PM PDT Monday...Expect the moderate winds to
decrease through much of the day, with a diminishing northwest
swell prevailing. A strong low pressure system arrives tonight
and lasts into mid week. This will bring widespread rain and
strong southerly winds especially in the southern waters, where
isolated gusts could reach storm force. A west swell will combine
with wind wave to create high and steep seas.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tday...Wind Advisory...CAZ006-508>510-512>516-528>530
High Wind Warning...CAZ517-518
SCA...SF Bay
SCA...Pt Arena to Pt Reyes 0-10 nm
SCA...Pt Reyes to Pigeon Pt 0-10 nm
GLW...Mry Bay
GLW...Pigeon Pt to Pt Pinos 0-10 nm
GLW...Pt Pinos to Pt Piedras Blancas 0-10 nm
GLW...Pigeon Pt to Pt Piedras Blancas 10-60 nm
SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm until 3 AM
SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm until 3 AM
SCA...Pt Arena to Pigeon Pt 10-60 nm
&&
$$
PUBLIC FORECAST: DialH
AVIATION: McCorkle
MARINE: Miles
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