Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/31/23
Area Forecast Discussion
National Weather Service La Crosse WI
1045 PM CDT Sun Jul 30 2023
.DISCUSSION...(This evening through Sunday)
Issued at 149 PM CDT Sun Jul 30 2023
Key Messages:
- Seasonable temperatures with patchy morning fog Monday.
- Slight Rain & Storm Chances in Spots Tuesday Night Through
Friday.
- Seasonable Temperatures Continue Through Work Week.
Overview:
GOES-16 Nighttime microphysics satellite imagery showed valley fog
forming by 09Z and continuing through 12Z with a couple of low lying
locations dropping to 1/4SM (Black River Falls/Boscobel). Able to
see the La Crosse River valley fog this morning and the
Mississippi River Valley fog remaining in the channel, not making
it to the KLSE ASOS.
Water vapor satellite imagery continues to have a large closed low
over Quebec and the large 500mb ridge covers much of the Rockies and
Southern Plains. A couple of clusters of storms were noted; one over
southwest Arizona moving west, and another across South Dakota
riding the elevated CAPE instability gradient.
Seasonable Temperatures With Patchy Morning Fog:
Morning low temperatures this morning were in the 40s and 50s, and
look for similar readings Monday morning. Surface high pressure
will build across the Upper Mississippi Valley tonight and Monday
with the center of the high pushing toward lower Michigan by 00Z
7.31. Again, forecast soundings show favorable conditions for
valley/river fog with a low level inversion setting up, very light
surface winds and light winds through the lowest 1 km. GFSlamp
data is more aggressive with fog as well over southwest Wisconsin
with the light winds and recent rains. The latest RAP is advancing
mid clouds faster Monday morning, thus will be something to keep
an eye on. Have included valley fog in the grids and increased
coverage across southwest Wisconsin. Some weak positive vorticity
advection in the northwest flow aloft, however stronger shortwaves
remain to the west or northwest of the area. The main instability
axis is over the Plains, however some weak SBCAPE does try to
approach the southwest part of the forecast area. Forecast
soundings still look dry enough to keep it mainly dry through
Monday afternoon.
Synoptic Pattern And Precipitation Chances Through Midweek:
Mostly quiet weather continues into midweek with a stagnant synoptic
pattern. Increased upper level heights centered over the Desert
Southwest remain from a Rex Block with an equatorward low over
central Mexico. Besides diurnal fluctuations of increasing
heights, strong (80-100%) ensemble (GEFS 30.12Z; EPS 30.06Z)
agreement for these higher heights to advect slightly northward.
Locally, this northerly synoptic advection results in more limited
midweek precipitation chances. The attendant increased low level
theta e lobe, evident on 30.12Z RAOBs over Montana in the 75th
percentile when compared to climatology, is forecasted to remain
well to our north. Therefore, the best low level moisture
transport remains well north of the Canada-Minnesota border as
well. While the extreme southern periphery of this precipitation
may graze local counties in central Wisconsin Tuesday night into
Wednesday morning, currently contains very limited confidence
(10-30%).
Similar limited confidence for counties in northeast Iowa into far
southwest Wisconsin to be on the northern periphery of farther south
precipitation. While the aforementioned northern stream of
precipitation is associated with a digging upper level trough out
of Canada, only slight, minute perturbations are causing southern
edge of precipitation in Central Plains into Wednesday morning.
Latter Half of the Week Precipitation Chances:
While long term deterministic (GFS 30.12Z; ECMWF 30.00Z) models
usually handle and agree on large synoptic patterns well, the local
area from southeast Minnesota and northeast Iowa into western and
central Wisconsin remains sandwiched between an area of higher
heights and a ridge-flattening low, substantially limiting local
precipitation confidence. Ensembles (GEFS 30.12Z; EPS 30.06Z)
remain in better agreement, with low probability (0-30%) for
greater than a tenth of an inch from Wednesday night into
Thursday morning. Both ensemble models prognostically trending
drier as well. In other words, the only outlier with a wetter
solution remains to be the deterministic GFS (30.12Z) at the
current forecast hour (84- 96 hours). Any deterministic
differences only amplify into next weekend.
What all this forecast mumbo rambling means is have toned down PoPs
to only slight chances along our southern counties in northeast
Iowa and far southwest Wisconsin from Tuesday Night through Friday.
Elsewhere, have slightly trimmed National Blend slight chance of
PoPs while continuing bulk of the areal coverage.
Seasonable Temperatures Continue Through The Work Week:
Temperatures appear normal for much of the week, in the 80s area
wide. Warmest days in the high 80s to potentially low 90s
Wednesday and Thursday according to the National Blend exhibit
wide model spread. Warm and cold biases from GFS and CMC,
respectively, result in 7 degree warm and cold tails in box and
whisker plots. While evidence suggests trending temperatures down
from National Blend, due to limited magnitude and impacts combined
with the longer forecast hour prevents this forecaster from
varying anything.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1035 PM CDT Sun Jul 30 2023
Expecting VFR conditions through the TAF period, with a small
chance (around 20%) for patchy valley fog at LSE Monday morning.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
DISCUSSION...JAR/Zapotocny
AVIATION...JAW
AREA FORECAST DISCUSSION
National Weather Service Bismarck ND
1006 PM CDT Sun Jul 30 2023
.UPDATE...
Issued at 1006 PM CDT Sun Jul 30 2023
Severely slashed PoPs to reflect that nothing happened early and
to match the HRRR more since it has been the most accurate over
the last 5 hours. Still looking at the next wave to move in around
7z or 8z, lasting through the morning. Currently those storms are
getting close to Glasgow.
UPDATE Issued at 656 PM CDT Sun Jul 30 2023
Currently the only storm of concern is in northeastern Montana one
county away from the North Dakota border. They are severe wind
gust from the outflow boundary and some severe hail. It will
probably enter our area around 7pm MT. The HRRR in the last hour
has really backed off on the convection entering our area until
08z but the other CAMs have storms this evening, as well as around
08z. The environment seems somewhat capped but has around 2000
J/kg of MUCAPE and 45-50kts of shear. The next wave (for 08z) is
in central Montana currently.
&&
.SHORT TERM...(This Evening through Monday)
Issued at 245 PM CDT Sun Jul 30 2023
Current surface analysis places low over eastern Wyoming, with
high stretching from central Saskatchewan into the upper Midwest.
Upper level analysis places high over Colorado, with ridge
northward through Montana into western Saskatchewan. A variety of
short waves are noted in the flow.
For late this afternoon and tonight, severe thunderstorms become
the main concern, particularly over western portions of our area.
Models have been quite consistent with advertising quite high deep
layer shear values of 50 to 60 kts for this evening, particularly
over southwest into portions of northwest North Dakota, with
values still above 40kts to the east. As for instability, plenty
of moisture continues to pull in over the aforementioned surface
low, with dewpoints already in the mid-60s noted over parts of
southwest North Dakota, while CAPE values of 1 to 2 kJ/kg are
already noted. High-res models continue to indicate storm concerns
for us should start early this evening, with a gradual progression
to the east. Greatest concerns for large hail/damaging wind gusts
remain over the southwest/far northwest, with a lesser concern but
still a potential as you go further east later tonight into early
Monday morning.
On Monday, some storms may be lingering from the overnight
convection into the early morning. Then concern shifts towards
what happens in the afternoon/evening hours. Again, deep layer
shear will be elevated, on the order of about 50kts, and
CAPE values of 1 to 2 kJ/kg will actually be spread out further to
the east than today. The fly in the ointment, though, is forcing
and whether we can get storms to develop. So, the severe threat
remains rather conditional, as there is a chance we will not see
any storms, but if we do have storms develop, severe will be a
great possibility.
.LONG TERM...(Monday Night through Sunday)
Issued at 245 PM CDT Sun Jul 30 2023
Perpetual chances for showers and thunderstorms continue on
Tuesday as we see another wave move through the area. Temperatures
will be warmer, with highs in the mid 80s to the mid 90s.
Wednesday is looking dry as upper ridge tries to gradually push
over. For the later part of the week models are having some
trouble coming to an agreement. With that said, will continue with
modest precipitation chances through this period, along with a
cooling trend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday Evening)
Issued at 1006 PM CDT Sun Jul 30 2023
VFR unless in heavy thunderstorms out west early in the morning
around 08z. Tempos are in place where confidence is slightly
higher on the thunderstorms, models have a few different ideas.
Winds will stay around 15kts from the southeast. CLouds should
clear after the morning convection. A chance for showers and
thunderstorms remain all day.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Smith
SHORT TERM...JJS
LONG TERM...JJS
AVIATION...Smith
Area Forecast Discussion
National Weather Service Burlington VT
1043 PM EDT Sun Jul 30 2023
.SYNOPSIS...
A cold front brings scattered showers and thunderstorms to the
region on Monday, followed by dry weather and cooler than
normal temperatures through Wednesday. The latter half of the
week features a warming trend back to normal and a return of
more unsettled conditions.
&&
.NEAR TERM /THROUGH MONDAY NIGHT/...
As of 1037 PM EDT Sunday...We continue to monitor isolated to
scattered rain showers across srn Quebec and sern Ontario. An
embedded shortwave trough and SBCAPE 100-250 J/kg per SPC
Mesoanalysis is supporting some embedded thunderstorm activity
north of Ottawa, where sfc temperatures are only in the upper
50s. Overall trend in 00Z NAM Nest and HRRR is to decrease
areal coverage as activity continues sewd into nrn VT and far
nrn NY next 1-3 hours. At this point, appears CAPE will diminish
and have not included mention of tstms, but kept 20-30 PoPs for
light rain showers. Mid-level clouds should limit fog potential
overnight, but have included just in the CT River Valley.
Overnight lows are expected in the 50s, and locally in the mid-
upper 40s across the northern Adirondacks.
Previous Discussion...Gorgeous late Summer weather is currently
underway with plentiful sunshine and refreshing humidity. Dew
points are in the mid 40s to mid 50s instead of the mid 60s to
low 70s of late. A moisture- starved shortwave traversing the
region has led to an increased coverage of mid- level clouds
across northern NY and portions of VT. However, those clouds
should diminish in coverage towards the evening hours as the
piece of shortwave trough exits.
Heading into tonight, another weak albeit slightly more
organized shortwave approaches the region. WPC surface analysis
shows a cold front draped across central Ontario into central
Quebec. That feature will slide south and approach the St
Lawrence valley on the Canadian side shortly after midnight. As
it does, expect southwest winds to increase due to a combination
of pressure gradient differences and channeling effect up the
St Lawrence valley. Besides 20 to 25 mph gusts at times,
overnight lows across the St Lawrence valley and the Champlain
valley will be relatively mild compared to the Adirondacks and
east of the Green Mountain spine thanks to adiabatic warming
from downsloping. So overnight lows across locations like
Massena and Burlington could be in the mid to upper 50s whereas
Saranac Lake drops to mid 40s. By the pre-dawn hours to near
daybreak, there could be some isolated sprinkles or spot
showers across our northern zones.
On Monday morning, there is the chance for scattered showers and
thunderstorm ahead of the aforementioned sharp cold front. K
index values rise into the low to mid 30s and along with
500-1000 J/kg of CAPE, there should be a few thunderstorms.
Thunderstorms should be garden variety and sub-severe. Also
given the progressive nature of the frontal passage, not
expecting flooding concerns. So that means we should also see a
rather sharp clearing as northerly flow advects in the driest
and coolest air mass that we have seen since late spring. The
forecast challenge is how low to go for overnight lows for
Monday night. 925mb temperatures fall to +8C to +10C, which is
more typical for late September according to the SPC sounding
climatology for our region. It is less certain that we will
realize the full radiational cooling effect due to a combination
of boundary layer winds and on-and-off cloud cover. Mesoscale
guidance shows a ribbon of H5 shortwave energy moving into our
area sometime overnight Monday around the base of a positively
tilted H5 trough. Did lower overnight lows a little below high-
res guidance with colder MOS solutions but did not go all the
way. Still thinking that SLK should see upper 30s along with low
40s across the colder hollows in NEK and east of the Greens,
but upper 40s to low 50s across the Champlain Valley and urban
heat islands like Burlington.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 242 PM EDT Sunday...A ridge of high pressure will move in from
the Great Lakes, bringing with it some much needed sunshine for the
first half of the week. Even better, an upper level trough will work
to keep temperatures nice and cool, with daytime highs remaining 5
to 10 F below climatological norms Tuesday and Wednesday.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 242 PM EDT Sunday...More exciting weather will return for the
latter half of the week and into the weekend. The chance of rain and
will begin to increase Thursday night in advance of a warm front
associated with a low pressure system moving into Quebec. A
cold front will follow on the heels of the warm front, and could
bring thunderstorms Friday and Saturday afternoon. The system
will move out quickly and we will return to pleasant conditions
Sunday.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
Through 00Z Tuesday...A cold front with showers and a few
rumbles of thunder across southern Canada is slowly approaching
our northern TAF sites. This boundary will increase the mid
level cloud deck this evening and should keep boundary layer
winds at 5 to 10 knots, preventing fog/br development. Have VCSH
shower aft 06z and continuing for most of Monday across our taf
sites. Mostly VFR conditions prevail overnight with a trend
toward MVFR at SLK/EFK and MPV on Monday. A brief period of IFR
cigs are possible at SLK btwn 12-15z Monday, associated with
deepening moisture in upslope flow behind boundary. Otherwise,
winds shift to the north/northwest at 5 to 10 knots on Monday
morning and continue into the aftn hours, with decreasing shower
chances by evening.
Outlook...
Monday Night: VFR. NO SIG WX.
Tuesday: VFR. NO SIG WX.
Tuesday Night: VFR. NO SIG WX.
Wednesday: VFR. NO SIG WX.
Wednesday Night: VFR. NO SIG WX.
Thursday: VFR. Slight chance SHRA.
Thursday Night: Mainly VFR, with areas MVFR possible. Likely
SHRA.
Friday: Mainly MVFR, with local VFR possible. Likely SHRA, Chance
TSRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Chai
NEAR TERM...Banacos/Chai
SHORT TERM...Langbauer
LONG TERM...Langbauer
AVIATION...Taber
Area Forecast Discussion
National Weather Service Cheyenne WY
525 PM MDT Sun Jul 30 2023
.SHORT TERM...(This evening through Tuesday night)
Issued at 310 PM MDT Sun Jul 30 2023
Forecast challenges deal with severe thunderstorms today and
Monday. Heavy rain chances begin to pick up the end of the short
term.
Currently...Boundary remains west of Cheyenne this afternoon and
is currently situated along a line from Denver to just west of
Cheyenne to Douglas and northwest to Greybull to western Montana.
East of this front...current dewpoints in the mid 60s in the
Panhandle (Sidney at 65) to the mid 50s here at Cheyenne and 59 at
Guernsey. SPC RAP analysis still showing a capped environment
looking at MLCAPE with -75 J/KG CAPE. 0-6km shear 30-35kts across
the southeast Wyoming plains into the Panhandle at 2PM. Convection
beginning to start over northern Colorado and out across Albany
County where low level cap has eroded. A Slight Risk area from SPC
is in effect for areas along and east of Cheyenne to Garrett to
Casper.
For the rest of the afternoon...MLCIN erodes east of the Laramie
Range east of the Laramie Range around 22Z...with MLCAPE of 1000
to 2500 J/KG out into the Panhandle. Mesoscale simulated radar
showing storms developing at any time now in this unstable
airmass...moving east northeast into the Panhandle and bowing out
into a line as it moves through the Panhandle. Could see large
hail with these discreet cells as the main hazard...turning to
strong downburst winds as the cells congeal into a line in the
Panhandle late this afternoon and early evening.
Depending on what happens in the Panhandle this evening...there
may be another round of low clouds and fog that develops
overnight. Especially if we do get a lot of rainfall out there.
Went ahead with a persistence forecast for overnight stratus/fog
for the Panhandle say 10 to 15Z.
Questionable for severe thunderstorms Monday. Especially if we get
the stratus in the Panhandle. GFS forecast sounding transitioning
to a heavy rain profile with long/skinny CAPES and high PWATS.
Panhandle PWATS up near 1.25 inches in the Panhandle and near 1
inch here at Cheyenne. Storm motions generally under 20kts across
the area...so slow moving storms will definitely be a concern for
heavy rainers Monday. We are outlined in a Marginal Risk for
severe storms for Monday afternoon. May see that change in later
updates.
Definitely by Tuesday...we are in a heavy rain type scenario where
PWATS range from 1.4 inches in the Panhandle to 1.25 inches at
Cheyenne to near .9 inch at Rawlins. Slight Risk area for
excessive rainfall has been outlined for extreme southeast Wyoming
in WPC`s Excessive Rainfall Outlook. Later shift will need to
consider a Flash Flood Watch for Tuesday afternoon for some
areas.
.LONG TERM...(Wednesday night through Sunday)
Issued at 310 PM MDT Sun Jul 30 2023
The word to describe the long term forecast is moist. Between a
monsoon surge midweek and a potent shortwave by the end of the week,
expect daily chances for numerous showers and thunderstorms.
An upper-level ridge over the center of the country will keep the
CWA in moist southwesterly flow through about Thursday. The
strongest push of monsoon moisture in the long term will occur on
Wednesday as it will be accompanied by a shortwave to the
northwest. This will likely lead to widespread and numerous
thunderstorms across the area. Model soundings show the typical
heavy rain profile with tall, skinny CAPE, modestly moist low and
mid-levels, and PWs around 1 inch. Soundings also indicate that
storms could be slow moving as cloud layer winds across much of
the CWA are under 10 kts. Heavy rain coupled with slow moving
storms could lead to increased potential for flooding. Currently,
much of the CWA is in a marginal to slight risk for excessive
rainfall on Wednesday. On Thursday, monsoon moisture begins to get
cut off as flow aloft turns more zonal with the weakening and
flattening upper-level ridge. There is still some lingering
moisture on Thursday in the Nebraska panhandle with elevated PWs
above 1 inch. Therefore, cannot rule out storm chances across the
area again.
Friday through Saturday, a potent, but moist shortwave drops in from
the northwest dragging a cold front behind it. Friday looks fairly
similar to Thursday with drier conditions out west but still
elevated PWs over the panhandle. Again, storm chances will be
possible. Saturday, a bigger push of moisture comes which will lead
to more widespread precipitation. PWs across the CWA range from 0.75
to 1.25 inches on Saturday with model soundings showing saturated
profiles. Will have to monitor to see if flooding could be an issue,
but for now heavy rain looks likely.
Luckily, by Sunday, an upper-level ridge starts to build in from the
west which will dry conditions out considerably. Storm chances will
be non-zero as the CWA will be in more northwest flow which is
favorable for storms. However, precipitation will be less
widespread, with perhaps a few isolated showers and storms possible.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 516 PM MDT Sun Jul 30 2023
Wyoming Terminals... Isolated showers and some stronger
thunderstorms are currently present across southeast Wyoming.
These storms are not expected to impact terminals, but a few
terminals could see some rain. VFR conditions are expected to
continue at KRWL and KLAR, but KCYS may drop to MVFR conditions
early in the morning due to some light fog across the terminal.
The fog is expected to move out of of the terminal by 14Z.
Nebraska Terminals... Minimal showers and thunderstorms currently
across western Nebraska, but this is likely to change over the
next few hours. Storms may become more widespread this evening and
potentially impact most of the terminals. Removed the TEMPO
groups for thunderstorms due to lower confidence in whether these
storms will stay together into the evening. After the
thunderstorms move out of the region, fog and low ceilings may
become an issue at KBFF, KSNY, and KAIA. Could see IFR to LIFR
conditions across these terminals beginning around 11Z and likely
ending by 15Z.
&&
.FIRE WEATHER...
Issued at 310 PM MDT Sun Jul 30 2023
Increasing monsoonal moisture set to move into southeast Wyoming
and Nebraska Panhandle tonight into the next work week. Result
will be increasing coverage and chances for wetting rains and
thunderstorms. Still have fairly dry conditions for Monday and
Tuesday before the full onset of monsoonal moisture moves over the
area. This will result in chances for severe storms both Monday
and Tuesday afternoon before threat turns to heavy rain and flash
flooding. Fire weather concerns will be minimal the upcoming week
with this monsoon moisture in place.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...GCC
LONG TERM...SF
AVIATION...AM
FIRE WEATHER...GCC
Area Forecast Discussion
National Weather Service Dodge City KS
713 PM CDT Sun Jul 30 2023
...Updated Aviation Section...
.SHORT TERM...(This evening through Monday night)
Issued at 1238 PM CDT Sun Jul 30 2023
Midday water vapor satellite imagery and RAP upper air analysis
indicates a ~598 dm subtropical ridge is centered roughly over
Trinidad, CO, with longwave troughing over the eastern CONUS and a
strong cut-off low just off the southwest shore of British
Columbia, Canada. This cut-off low will slowly make its way east
through the short term period, pushing the subtropical ridge
southeastward with time. As the ridge passes nearly overhead of
southwest KS, strong synoptic-scale subsidence will allow 850-mb
temperatures to warm into the upper 20s/low 30s Celsius today,
which will translate to unpleasant afternoon highs in the upper
90s/near 100. The only silver-lining will be the mid/upper 60s
dewpoints will be confined to the far southeast zones of Pratt and
Barber counties, where heat indices will approach 105F. As such,
these are the only counties under a Heat Advisory through 02Z
Monday. Overnight tonight should be quiet, however there is a very
off chance decaying thunderstorms reach the northern zones. Based
on latest CAM/HREF guidance, this scenario appears quite
unlikely, and therefore the inherited dry forecast was maintained
with lows in the low 70s.
Daytime Monday, the upper level subtropical ridge will continue
its trek southeastward, reaching the southern plains by 12Z
Tuesday. Short range guidance agrees 850-mb temperatures will
increase further into the low 30s Celsius, promoting a slight
uptick in afternoon temperatures with highs in the low 100s. Once
again, mid/upper 60s dewpoints will be restricted to Pratt and
Barber counties, where another Heat Advisory is in effect through
02Z Tuesday. Monday night, thunderstorms developing over the
higher terrain in eastern CO may reach closer to our area, but
there is no indication any activity will actually enter southwest
KS, so another quiet overnight period is forecast with lows in
the low/mid 70s.
.LONG TERM...(Tuesday through Sunday)
Issued at 154 PM CDT Sun Jul 30 2023
Key messages: Intense heat will likely persist Tuesday and
Wednesday. Cooling trend begins Thursday along with appreciable
precipitation chances through the end of the period.
Medium range ensemble guidance continues to agree the upper level
subtropical ridge will be centered over the southern plains
at the beginning of the long term period, and will move very
little through mid-week. With enduring synoptic-scale subsidence
over the central plains fostering unrelenting solar insolation and
increasing 850-mb temperatures, afternoon highs ranging from the
upper 90s northwest to around 103-105 southeast are on tap Tuesday
and Wednesday. Heat advisories will likely be needed across
portions of our area both days as dewpoint temperatures in the mid
to perhaps upper 60s support heat indices reaching advisory level
criteria.
The good news is, this should be the last couple days of intense
heat across the area for the foreseeable future as ensembles
suggest increasing westerly flow aloft owing to the weakening and
retrograding subtropical ridge allows intrusions of cooler air as
well as precipitation chances. Both the GEFS and EPS ensemble
means show a steady decline in afternoon temperatures starting
Thursday, with daily drops of around 3-5 degrees down into the 80s
by Sunday. Ensemble meteograms also show a strong signal for
daily thunderstorms/precipitation beginning Thursday evening and
lasting through the end of the period as upper level shortwave
troughs eject into the High Plains. This is supported by NBM PoPs
well into the chance category (25-54%) each evening Thursday-
Sunday, so it appears likely our abnormally wet summer and
calendar year will continue.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 707 PM CDT Sun Jul 30 2023
Initial conditions for this TAF set have south to southwest winds
in the 10 to 15 knot range. A small cluster of storms up north of
HYS terminal may clip HYS around sunset, so we added a couple
hours of VCTS up there. An outflow boundary from overnight
convection across southern Nebraska will likely push far enough
south to change the wind direction at HYS very early in the
morning. VFR flight category is forecast through the period.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 73 102 74 102 / 10 0 0 0
GCK 71 100 72 98 / 10 0 0 0
EHA 71 99 70 99 / 10 0 0 0
LBL 71 101 73 101 / 10 0 0 0
HYS 73 104 73 101 / 10 10 0 0
P28 73 103 75 104 / 10 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 1 PM to 9 PM CDT Monday for KSZ030-031-045-
046-064>066-079>081-089-090.
Heat Advisory until 9 PM CDT this evening for KSZ081-090.
&&
$$
SHORT TERM...Springer
LONG TERM...Springer
AVIATION...Umscheid
Area Forecast Discussion
National Weather Service Duluth MN
639 PM CDT Sun Jul 30 2023
.DISCUSSION...(This evening through Saturday)
Issued at 358 PM CDT Sun Jul 30 2023
Summary: Dry conditions will prevail into Tuesday before rain
chances return for the latter half of the week. Temperatures will
slowly warm into midweek before returning to more seasonal values
for late week and into the weekend.
High pressure stretched from Saskatchewan into the Upper Midwest
this afternoon with dry conditions across the Northland. A few
isolated showers were observed on radar at times across the
Minnesota Arrowhead, but this activity was not likely reaching the
ground. Skies are expected to clear this evening, but smoke aloft
will filter into the region with northwest flow. Have added more
cloud cover than what the models want to put in based on the HRRR
smoke trends and have added FU to the grids as well to account for
this. This will mainly affect the northern half of the Northland.
Most of the smoke is expected to remain aloft and not really mix
down with surface high pressure in place.
Dry conditions are expected for Monday outside of an isolated
shower or two in the tip of the Arrowhead. High pressure will move
to our east on Tuesday as a shortwave approaches. It may lead to a
few showers and thunderstorms Tuesday night into Wednesday with
perhaps better chances Wednesday evening. The GFS continues to
advertise low chances for a few severe storms Wednesday evening,
but forcing looks to be an issue. A weak cold front then passes on
Thursday bringing cooler and more seasonal temperatures to end the
week. Rainfall chances will then return for the weekend as global
models continue to advertise low pressure developing across the
Plains and then lifting northeast as a stronger trough moves
through aloft.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 639 PM CDT Sun Jul 30 2023
Smoke aloft was advancing over northeast Minnesota this evening.
Look for VFR conditions for most of the night. Mist and fog is
possible at HIB, BRD, and HYR. Conditions at HYR have dropped into
LIFR range the past several mornings. Without a pattern change,
we expect the same thing to happen tonight. Near-surface smoke may
become an issue at INL Monday afternoon, otherwise milky skies
and visibility of 6 miles or more will be the main concern from
smoke.
&&
.MARINE...
Issued at 358 PM CDT Sun Jul 30 2023
No significant marine concerns are expected over the next 48
hours. Winds will diminish this evening and become light overnight
before turning northeasterly Monday afternoon. Onshore winds will
continue for Tuesday at 5 to 15 knots. An isolated thunderstorm
will be possible Monday and Tuesday afternoon north of Taconite
Harbor, but overall chances are low.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 55 82 56 80 / 0 0 0 10
INL 51 82 54 82 / 0 0 10 40
BRD 55 85 59 86 / 0 0 10 10
HYR 51 82 55 84 / 0 0 0 10
ASX 55 83 55 84 / 0 0 0 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&
$$
DISCUSSION...BJH
AVIATION...Huyck
MARINE...BJH
AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
645 PM CDT Sun Jul 30 2023
.Discussion...
Issued at 256 PM CDT SUN JUL 30 2023
Key Message
* Showers and thunderstorms Sunday night, into Monday morning. Some
storms may be strong, but widespread severe weather not expected.
* Very warm and humid once again for Tuesday and Wednesday
* Daily chances for thunderstorms return late this week, into
weekend.
Seasonally warm and humid airmass in place on Sunday has brought
high temperatures touching 90 degrees in some locations. Dewpoints
in the upper 60s to lower 70s have contributed to heat indices a few
degrees higher than going temperatures. This within a broad area of
southeasterly surface winds just east of a developing surface low
over the central High Plains. In the mid levels a stout ridge
continues to exert its influence over the southwestern CONUS, where
hot and dry conditions persist. Around the periphery of the ridge
there is some useful flow, associated with a broad trough over
Hudson Bay. This area of flow between the SW CONUS ridge and the
Hudson Bay low will keep chances for precipitation going for the
next couple days. Satellite imagery at this time looks pretty barren
for any promising rain prospects this afternoon and evening, but
that should change going into tonight. A strong isentropic component
found mostly on the 310-315K Theta E surfaces will contribute to an
area of broad ascent later tonight. There will be a corridor of
richer moisture running NW/SE within the warm air advection regime,
between roughly KSLN and KCOU. This corridor of moisture will be the
areal focus for elevated showers and thunderstorms tonight. The
exact areal extent of the better precipitation chances still needs
to come into better focus. HRRR indicates blossoming convection just
after midnight, perhaps just east of the KC Metro, into central
Missouri. This is a very plausible area of initiation, but with the
low level jet nosing in a little further west, across central and
eastern Kansas, it`s also plausible that we could see the convection
form a little further west, into eastern Kansas and western
Missouri. Early IR channel trends with growing CU/ACCAS tonight
after sunset should help bring to into focus where these storms will
form. Despite the richer moisture being in place along that
aforementioned corridor, MU CAPE should max out around 2000-2500
J/kg. However, the aforementioned corridor of better flow aloft will
help contribute to 40+ kts of shear, which may help with some
persistent updrafts. Overall, expect low end severe weather concern
for tonight, but some of the more robust storms may have some hail
around 1 inch.
The story for Monday will be somewhat conditional on how the
convection plays out Monday morning. Left over showers and cloud
debris will certainly play a role in just how warm it can get. With
the better chance of mid/late morning/early afternoon showers in
central Missouri, it`s possible that area will remain a bit cooler,
while areas of far EC Kansas and WC Missouri could be a bit warmer
should clouds clear out sooner. This may leave the far southwestern
corner of the CWA vulnerable to heat concerns Monday afternoon.
By Tuesday, the SW CONUS ridge will shift a bit to the east, and
become a little more focused on the central part of the CONUS. This
should bring a bit of drying trend for the early to middle part of
the week. It may also mean warmer temperatures and a return of the
oppressive heat and humidity we have been dealing with, lately.
The extended forecast brings a bit of good news, with respect to
heat and precipitation. There are some signs in the deterministic
operational models of the ridge at the very least flattening out, if
not completely breaking down. This will mean more mid level flow
over the area, which will help with daily chances for rain and a
break from the oppressive heat. While pinpointing any promising
chances for rain is not probable at this point, the shift in the
pattern may bring more active weather and slightly cooler
temperatures to the area perhaps as early as middle to late this
week, into the upcoming weekend.
&&
.Aviation...(For the 00Z TAFS through 00Z Monday Evening)
Issued at 644 PM CDT SUN JUL 30 2023
A complex of thunderstorms is currently moving southward across
the region. These storms are expected to impact the terminals over
the next few hours. An additional round of storms is possible
later in the overnight; however, that will be conditional based
on the effect of this first round of storms. VFR conditions return
after sunrise.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
Discussion...Leighton
Aviation...Pesel
Area Forecast Discussion
National Weather Service Grand Forks ND
1008 PM CDT Sun Jul 30 2023
.UPDATE...
Issued at 1008 PM CDT Sun Jul 30 2023
Clouds have pretty much clearing (though smoke aloft is lingering
in MN causing some lingering "haze" to the night sky. Smoke
doesn`t impact nighttime temperatures like it does daytime
temperatures (longwave radiation still escapes) and as long as
clouds remain clear we should see good radiational cooling
particularly near the center of the surface ridge in our east.
Some adjustments were made to lows for tonight (nudging our east
closer to persistence similar to previous nights) and sky trends
to capture the lack of clouds currently and lingering smoke in our
east.
UPDATE Issued at 633 PM CDT Sun Jul 30 2023
Smoke aloft has overspread northwest MN as expected, but no
surface impacts have been reported. Latest RAP still shows main
period of possible smoke mixing to the surface near our northeast
CWA late Monday afternoon through Monday night. Forecast for
tonight is on track, so I mainly just adjusted sky trends to tweak
the location of sky cover impacts from smoke.
&&
.SHORT TERM...(This evening through Monday night)
Issued at 305 PM CDT Sun Jul 30 2023
Key Messages:
- Predominately dry and quiet conditions are forecast this evening
through Monday morning, however there is a low (15%) chance
showers and thunderstorms moving out of central North Dakota
push into portions of eastern North Dakota early Monday
morning.
- Isolated to scattered thunderstorms are forecast within North
Dakota and southern Manitoba Monday afternoon, of which may
develop or move into our area Monday afternoon into evening.
Some of this activity may be strong to severe.
- Smoke is forecast to reside over portions of northern Minnesota,
including Lake of the Woods to Bemidji area. Some smoke is
expected to be at the surface level Monday into Monday night.
Discussion:
For the rest of today, northwest flow aloft with surface high
pressure will allow predominately dry and quiet conditions this
evening through Monday morning for most of the area. There is an
area of slightly agitated Cu near the international border, with
some CAMs showing some showers possible within this area. However,
a lack of instability, moisture, and forcing should preclude this
activity from becoming widespread or robust. This is the most
likely scenario, and is reflected within the forecast.
However, there is around a 15% chance of residual convection
moving out of central North Dakota to push into portions of
eastern North Dakota early Monday morning, feeding off of a
reservoir of instability and better moisture content within the
western half of the state. Confidence is low in this scenario as
it will depend on mesoscale and storm-scale aspects such as the
track of any thunderstorm complex that may or may not be sparked
by weak forcing from subtle waves moving through the crest of the
upper ridge over the northern High Plains, in addition to
uncertainty on whether or not storms become cut off from better
thermodynamics to the west. Overall chances for strong to severe
hazards with this activity is quite low, less than 10%.
Getting into Monday afternoon and evening, the upper ridge over
the western CONUS continues to build, with its axis slowly
building into the northern High Plains. This will help advect
the warmer and more moist air mass currently within the western
Dakotas into our area. Additionally, this will help continue to
allow subtle mid and upper level waves moving through the flow to
push through the region. Most of these waves are quite unorganized
and nebulous meaning weak forcing for ascent aloft, but
nevertheless present. This also will help keep kinematics enhanced
with mid and upper level winds increased around 50 kt or more
owing to high confidence in shear to be present over our area.
With shear in place and instability pushing into our area,
convection from subtle waves will have a better chance for
organization allowing strong to severe hazards to become possible
tomorrow.
This morning`s guidance depicts a general scenario of robust
convection becoming possible in the afternoon to evening hours
within North Dakota into southern Manitoba, of which will have a
chance to advect into our area. Because of the weakly forced
regime, confidence is low in determining a more refined timing other
than Monday afternoon and evening, while favoring locations within
eastern North Dakota closer to the reservoir of instability.
Because of the weakly forced regime and lack of better surface
boundary/forcing, multicell and semi-discrete storm mode is
expected, with supercellular characteristics expected.
With this in mind, a lack of better low level shear, the tendency
for storms to likely be elevated in height, instability between
1-2 kJ/kg, and generally unidirectional shear in excess of 40 kt,
hail up to ping pong balls and gusty winds to 60 mph are the
potential hazards within strongest storms.
.LONG TERM...(Tuesday through Sunday)
Issued at 305 PM CDT Sun Jul 30 2023
Upper ridging is forecast to be at its strongest Tuesday into
Wednesday over the Northern Plains. This will help push unstable
and warm air mass into the region, potentially very unstable.
Similar to Monday, guidance continues to indicate the presence of
numerous, subtle and weakly organized mid and upper level impulses
moving through the crest of the ridge over the region amid a belt
of enhanced westerlies aloft. This increases confidence in shear
to remain in place through at least Wednesday, but lowers
confidence in focus forcing for ascent. At the surface, guidance
does hint at a surface boundary/front helping push the
unstable/warm air mass east and south of the area between late
Tuesday and Wednesday, which may help provide a bit more focus for
ascent within our area.
Long story short, the chance for thunderstorms will remain in the
forecast Tuesday through Wednesday, of which could be strong to
severe given the instability and shear expected to be present
over the area. However, because of the uncertainty regarding
forcing mechanisms, confidence remains low on severe hazard
magnitude, timing, and location.
After Wednesday, the surface boundary/front is helped
east/southward by upper troughing over the Hudson Bay helps shunt
upper ridging and re- introducing northwest flow aloft helping
moderate temperatures and decrease chance for showers and
thunderstorms.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 633 PM CDT Sun Jul 30 2023
VFR conditions should prevail across eastern ND through the TAF
period and most of northwest MN through Monday afternoon, with
periods of shallow CU around 6000 FT AGL mainly during daylight
periods. Prevailing winds will remain light due to high pressure
tonight, but eventually shift to the southeast and increase to
8-12kt Monday as low pressure builds from the west. Very low
shower/thunderstorm chances (15% or less) arrive Monday morning
in ND with a break and possibilities again during the late
afternoon/evening in ND (15-30%). Mention was left out of TAFs at
this time due to low chances. Smoke has overspread northwest MN
aloft, and guidance shows smoke eventually mixing to the surface
near the end of the valid TAF period at KBJI through Monday night.
Confidence in MVFR vis is still low, but at least some vis
reductions will be possible after 23Z.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...DJR
SHORT TERM...CJ
LONG TERM...CJ
AVIATION...DJR
Area Forecast Discussion
National Weather Service Flagstaff AZ
830 PM MST Sun Jul 30 2023
.SYNOPSIS...Widespread shower and thunderstorm activity is
expected across northern Arizona through Tuesday, followed by
decreasing coverage on Wednesday. Cooler temperatures are likely
through Wednesday, before a drying and warming trend develops
through the end of the week.
&&
.UPDATE...Isolated to scattered showers/storms remain primarily
along and north of the I-40 corridor this evening. Precipitation
activity will linger through the late evening hours, but overnight
chances for showers and storms look very minimal. As a result, an
update was made to the forecast to reflect a decrease in
precipitation chances overnight through the early morning hours.
Another round of widespread activity is in store for Monday. The U
of A 18Z HRRR WRF run is showing widespread activity beginning
around 11 AM MST tomorrow (Monday). The HREF most unstable CAPE
ensemble mean is also hinting at values between 500-1500 J/kg
across our CWA, so there should be plenty of instability for
storms to develop throughout the afternoon. Storms that do
form will likely be capable of producing heavy rainfall and
frequent lightning. Flash flooding will continue to be one of the
greater concerns with storm activity, so be sure to have a way to
receive weather warnings/updates!
&&
.PREV DISCUSSION /353 PM MST/...Deep moisture over northern
Arizona (0.83 Pwat on the 12Z sounding) and an approaching
inverted trough from the east ("easterly wave") helped trigger
widespread showers and thunderstorms today. A few storms became
anchored over terrain and produced heavy rain (over 3" in places)
and caused flash flooding.
Widespread showers and thunderstorms are expected both Monday and
Tuesday with lower daytime temperatures. As such, the excessive
heat warning for the lower elevations in The Grand Canyon has
ended.
By Wednesday, the center of the high pressure that has brought
the moist southerly flow will shift eastward. This will allow a
drier southwest flow to develop over northern Arizona. The high
will then shift and elongate over northern Mexico late in the week
which will cut off our moisture flow by Friday and will bring a
warming trend. So, enjoy the moisture and cooler temperatures
while they lasts, before the heat and dryness return.
&&
.AVIATION...For the 06Z TAF Package...Scattered showers and
storms will continue along and north of the I-40 corridor through at
least 08Z. With decreasing storm activity overnight, winds will
stay generally less than 10-15 kts. After 18Z, -SHRA/TSRA across
much of northern Arizona is expected. Erratic outflow winds of 30
to 40 knots possible near thunderstorms. Away from storms, mainly
VFR conditions with winds generally less than 15 knots. Aviation
discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Monday and Tuesday...Widespread showers and
thunderstorms expected each afternoon into the evenings. Storms may
produce frequent lightning, heavy rainfall rates, and gusty, erratic
outflow winds of 30 to 40 MPH. Slightly lower high temperatures
Monday and Tuesday. Outside of storms, expect west-southwest winds
around 10 to 15 MPH.
Wednesday through Friday...A warming and drying trend through the
week. Only isolated storms by Friday. Anticipate wetting rains
(>0.10") in any storms. Outside of storms, expect south-southwest
winds around 10 to 15 MPH.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
PUBLIC...Konieczny/MAS
AVIATION...Konieczny
FIRE WEATHER...MAS/Konieczny
For Northern Arizona weather information visit
weather.gov/flagstaff
Area Forecast Discussion
National Weather Service Glasgow MT
248 PM MDT Sun Jul 30 2023
.DISCUSSION...
AFTERNOON DISCUSSION:
The battle of the CAMs is the name of the game today. The showers
over southern Saskatchewan and the northern zones along the
International Border have been well represented by the HWR FV3,
though this specific HREF member has lacked in the shower
representation in our southern zones. Meanwhile the last couple
runs of the HRRR has been consistent with the storms forming over
the higher elevations of central Montana reaching the CWA and
merging more into a bowing quasilinear complex, moving to the
northeast. Given this consistency and forecast soundings, the
main threat with that scenario would be severe winds and possible
large hail into the overnight hours.
Monday morning, lingering showers in our eastern zones shift into
North Dakota, with clearing thereafter. Another round of
afternoon showers will happen, though the greatest chances for 40
dBZ plus storms will mainly be south of northeast Montana. After
midnight and into Tuesday, some storms that form over BYZ`s CWA
move northeast, potentially affecting Prairie and Wibaux Counties,
with the main threat being gusty winds and isolated cases of
large hail in the strongest storms.
Meanwhile, temperatures are on the rise for Monday and Tuesday,
with confidence in 90 degree plus max temperatures above 90%. RH
values these days are near 20%, but at this time, no highlights
are expected since winds remain under 20 mph. Tuesday night, a
cold front moves through the region, with the great chance for
wetting rain remaining closer the North Dakota border.
From Wednesday, monsoonal moisture will really get going and
advecting into the western US. The greatest chance for 24-hr
totals greater than 0.5 inches is over northwestern Wyoming, with
a gradual decrease in probabilities northward. Our southern zones
will relatively will have the greatest chances for precipitation.
On Thursday, the probability for wetting rain for the southern
zones is between 30 and 50%, and then 20 to 40% on Friday.
-Enriquez
&&
.AVIATION...
LAST UPDATED: 2045Z
EXPECTED FLIGHT CAT: Possible MVFR/IFR in an showers or
thunderstorms, otherwise VFR.
DISCUSSION: Overnight, some high-resolution model consensus shows
a bowing segment of showers and thunderstorms that will move
through northeast Montana, bringing at times severe winds at the
apex of the blow.
WINDS: East 10-15kts. In and in the vicinity of thunderstorms,
gusts will be erratic. By morning, winds east of KGGW will be from
the south at near 10kts and in the western zones will be light and
variable.
-Enriquez
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
weather.gov/glasgow
Area Forecast Discussion
National Weather Service Green Bay WI
1047 PM CDT Sun Jul 30 2023
Updated aviation portion for 06Z TAF issuance
.SHORT TERM...Tonight and Monday
Issued at 309 PM CDT Sun Jul 30 2023
It has been a quiet afternoon with surface high pressure centered
around northwest Wisconsin. Cumulus clouds have formed, and there
is still an outside chance for a sprinkles or a quick shower late
this afternoon. Most places will stay dry.
Clouds will dissipate this evening with mostly clear skies to
start out the night. Some patchy fog is possible after midnight.
HRRR and RAP smoke models indicate smoke aloft will start to drift
into northern Wisconsin late this evening, and spread across the
entire forecast area Monday morning. While models are indicating
decent smoke aloft, there is little to none reaching the surface
on Monday. Therefore, included haze in the grids with the
expanding smoke, but did not include surface smoke. Visibilities
upstream are also looking okay, indicating this wave of smoke may
stay aloft.
Aside from the smoke, expect daytime cu to develop again. Forcing
overall is fairly minimal, but with a very weak shortwave and
CAPE around 300 J/kg, cannot rule out a few afternoon showers or a
clap of thunder. Best chance will be in far northeast Wisconsin
near the bay and lake.
Temperatures will be fairly close to normal tonight and Monday.
With clear skies tonight lows will fall into the upper 40s in the
typical cool spots, with 50s elsewhere. Highs Monday will range
from the upper 70s to lower 80s.
.LONG TERM...Monday Night Through Sunday
Issued at 309 PM CDT Sun Jul 30 2023
500mb ridge across the central and southern plains will lead to a
northwest flow pattern across the western Great Lakes through the
end of next week before the ridge begins to flatten next weekend.
High temperatures will run at least a few degrees above each day.
There is a small chance of showers and thunderstorms early Monday
evening, otherwise the chances of showers and thunderstorms return
Tuesday night and then continue into Thursday.
For Monday night, an isolated shower or storm should dissipate
around sunset. Otherwise, areas of haze and patchy smoke are
expected during the evening. Patchy fog is also possible after
midnight. Tranquil conditions are expected on Tuesday with highs
in the lower to middle 80s. For Tuesday night, a cluster of
showers and thunderstorms will move across Upper Michigan and
Lake Superior. A few of the showers and storms could clip far
northern Wisconsin. On Wednesday, diurnally driven convection
is expected to break out across portions of north-central and
northeast Wisconsin. CAPE values of 500 to 1,500 J/KG along
with 0-6 km bulk shear values of 30 to 40 knots would support
scattered thunderstorms during the afternoon. Some of these
storms could become strong or severe if they do develop.
The forecast becomes muddled Wednesday night and Thursday
as a cold front moves across the area. The 12Z ECMWF is
now depicting and MCS moving into northern Wisconsin Thursday
morning. This could cause issues for convection along the
cold front Thursday afternoon. Strong or severe storms
are possible along the cold front Thursday afternoon if
we should see sunshine during the afternoon. Will have to
sort out the details in the coming days. Dry conditions
are expected Friday and Saturday, and Sunday will likely
be mostly dry. There is low confidence in the small
chance of rain on this day. Temperatures should return
closer to normal by next weekend.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1031 PM CDT Sun Jul 30 2023
VFR flight conditions are expected through at least Monday.
Mostly clear skies are expected during the overnight hours across
the region. Patchy ground fog is possible north of a AUW to IMT
line late tonight.
An elevated layer of smoke is expected to arrive Monday from
Central Canada. It will probably not affect surface visibility
very much. Some clouds will likely form Monday afternoon, and
there could be a shower in the far northeast corner of the
state. Any showers or cumulus clouds should dissipate by Monday
evening with the loss of daytime heating.
.OSH...clear skies are expected during the overnight hours. VFR
conditions are also expected Monday, with an elevated layer of
smoke and additional few to scattered cumulus clouds around 5000
feet. Cumulus clouds will dissipate Monday evening with the loss
of daytime heating.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM.....KLJ
LONG TERM......Eckberg
AVIATION.......Kurimski
Area Forecast Discussion
National Weather Service Memphis TN
734 PM CDT Sun Jul 30 2023
...New UPDATE...
.UPDATE...Issued at 727 PM CDT Sun Jul 30 2023
Updated to drop the heat advisory as temperatures have fallen
below advisory criteria across the Midsouth. Cooler, sub-advisory
temperatures are expected to continue through midweek with hot
conditions returning by Thursday.
The HRRR has an MCS approaching western portions of the Midsouth
late tonight, but the latest run keeps it just to our west over
central Arkansas. We will have to monitor this scenario for
additional MCS`s over the next few days, but in the absence of one
the forecast should be mostly dry.
30/Sirmon
&&
.SYNOPSIS...
Issued at 211 PM CDT Sun Jul 30 2023
A cold front has made its way through TN and into northern MS
resulting in slightly drier air and lower temps into the first
half of the week. Later this week, expect the ridge to return and
increase temps briefly before another cold front enters the
region.
&&
.DISCUSSION...
(This evening through next Saturday)
Issued at 211 PM CDT Sun Jul 30 2023
The Mid-South is still lodged between an upper level ridge from
the west and a shortwave trough on its eastern side. The ridge is
retrograding back west briefly in the beginning of the week
allowing NW flow to dominate and bring drier air and possible
convection into the area. There is still a small chance for a few
pop up storms this evening but confidence is very low and impacts
will likely remain very minimal.
For the next few days, chances for convection are more favorable
due to multiple disturbances rotating around the ridge. Tomorrow
morning into the afternoon, an unorganized complex of storms is
likely to move across MO and into central AR with the bulk of the
activity remaining to our west. Pops were added to include the NW
portion of our CWA. Continued upper level disturbances are
expected for Tuesday and Wednesday.
On Wednesday, the ridge returns slowly and by Thursday warmer
temperatures return to the region for the latter part of the
week. Heat headlines may be needed for Thursday and Friday. Friday
evening into Saturday, another cold front comes through the
region reinstating the slightly cooler temps and higher rain
chances seen at the beginning of the week.
&&
.AVIATION...
(00Z TAFS)
Issued at 544 PM CDT Sun Jul 30 2023
VFR conditions and generally light winds are expected overnight.
TUP and MKL may experience BR overnight with calm winds and clear
skies, but TUP may experience more impacts than MKL.
Tomorrow afternoon, a bowing segment of showers and thunderstorms is
anticipated to sweep through JBR and MEM. Winds may have
intermittent gusting as the line moves through and VISBYS may
decease (causing MVFR and potential IFR) for brief periods due to
possible TSRA. Confidence is low on direct impacts to MEM, so VCTS
will suffice.
DNM
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
PUBLIC FORECAST...JDS
AVIATION...DNM
Area Forecast Discussion
National Weather Service Marquette MI
724 PM EDT Sun Jul 30 2023
.UPDATE...
Issued at 724 PM EDT SUN JUL 30 2023
The forecast remains on track tonight. Diurnal cumulus streets
continue to diminish this evening, and skies should be clear across
most of the UP overnight. The exception will be in the eastern UP,
as patchy cloud cover from upstream convection is expected to move
southeast across Superior tonight. A few showers may even reach the
far eastern UP into the pre-dawn hours. Temperatures hover in the
lower to mid 70s still, but should be able to quickly fall back
through the 60s and 50s after sunset with another cool night ahead.
&&
.SHORT TERM...(This evening and overnight)
Issued at 138 PM EDT SUN JUL 30 2023
GOES Water Vapor and RAP analysis highlight well the ridge/trough
pattern across CONUS today. Within this flow, Upper Michigan has
been under the influence of surface ridging and northwest flow
aloft. This has supported a cloudy period around mid-day thanks to a
shortwave dropping southeast through the forecast area. Behind the
wave, diurnally driven strato-cu has developed. Daytime highs have
warmed mostly into the 70s across the region, and diurnal mixing has
supported minimum RH values in the region dipping into the 40s and
in some places, the high 30s.
Expecting skies to trend toward clear in the evening as we loose the
daytime heating. With the main synoptic drivers and dry air still in
place, expecting a cool night with lows in the upper 40s and 50s in
interior locations and upper 50s to near 60F by the lakeshores. A
stretched out PV streamer tied up in northwest flow aloft may be
able to support a stray shower or two by morning near Copper Harbor
and east of Munising, but confidence is low.
.LONG TERM...(Monday night through Sunday)
Issued at 245 PM EDT SUN JUL 30 2023
The North American western ridge/eastern trough pattern (+PNA)
amplifies into early week as low-amplitude shortwaves dig toward the
base of the trough. These clipper-like waves embedded within
northwest flow aloft over the Upper Great Lakes may support some
diurnal instability showers Monday afternoon. Marginal instability
and limited moisture suggests only isolated shower coverage and
light rainfall as many of the models have backed off on the MLCAPE
values from yesterday`s runs (now only a few hundred j/kg). With
northwest surface winds and perhaps the aid of developing lake
breezes off the Bay of Green Bay or northern Lake MI it looks like
the best convergence, and hence best shower activity should be over
the south-central UP which most of the CAMs are targeting. Highs
Monday should be mainly in the 70s.
The center of the surface ridge approaches on Monday and should be
overhead Monday night leading to good radiational cooling and
perhaps some shallow/patchy radiational fog too. Forecast interior
low temps are now in the mid-40s, which still may not be cool enough
across the interior east where EFI guidance indicates unseasonably
chilly temperatures. The surface ridge axis shifts east on Tuesday
with WAA ramping up during the day resulting in a large diurnal
temperature range as sunny skies allow temperatures to warm well
into the 70s and even lower 80s for western locations.
EPS and GEFS means indicate a surface low tracking east across
Ontario toward James Bay late Wednesday through Thursday placing the
UP within the warm sector. Wednesday and Thursday will be the
warmest and most humid days of the week with highs mainly in the
lower to mid-80s. More clouds and higher precip chances on Thursday
could shave a few degrees off high temps across the northwestern UP.
Quite a bit of ensemble spread persists for the Wed-Thu time frame
regarding the timing of the sfc low track across Ontario, but recent
model trends suggest that a slower cold front passage Thursday
afternoon/evening seems to be increasingly likely. Removed most PoPs
Tuesday night, but otherwise stuck with the model blend as models
continue to refine frontal timing and resultant PoPs. Modest MUCAPE
of 1000-1500 J/kg and bulk shear (=>40 kts) suggest the potential
for stronger to perhaps isolated severe storms, probably in the late
Wed night into Thu evening time frame. Shower and thunderstorm
potential diminishes quickly behind the cold front as a much cooler
and drier air mass returns for Friday into next weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 724 PM EDT SUN JUL 30 2023
VFR conditions prevail at all terminals through the forecast period.
Winds remain somewhat breezy out of the west/northwest this evening,
but will be generally light and variable overnight while skies
remain mostly clear. Skies remain mostly clear Monday, but some high-
level haze may be present as smoke from upstream wildfires spreads
over the area.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 245 PM EDT SUN JUL 30 2023
Winds should generally be less than 20 kt for most of the forecast
period. A low level jet Tuesday night brings the potential for south-
southwesterly gusts around 25 kt over the higher platforms of the
eastern lake that continues into Wednesday. A cold front Wednesday
night or Thursday shifts winds northwesterly with gusts around 20 kt
behind the front. Thunderstorm chances shift from west to east
across the lake late Tuesday night through Wednesday night with
chances lingering over the eastern half on Thursday.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
UPDATE...LC
SHORT TERM...JTP
LONG TERM...Voss
AVIATION...LC
MARINE...Voss
Area Forecast Discussion
National Weather Service Phoenix AZ
453 PM MST Sun Jul 30 2023
.Update...Updated 00Z Aviation Discussion
.SYNOPSIS...
As high pressure shifts to the east away from the region today,
an area of low pressure will approach from Mexico. This will
result in temperatures retreating somewhat closer to normal as
moisture levels increase. Today will bring an increase in shower
and thunderstorm chances to much of the area, particularly across
southwest Arizona. The unsettled weather pattern will continue
into Monday with eastern and central Arizona likely seeing the
best chances for showers and thunderstorms. While strong gusty
winds and dense blowing dust will be the primary weather hazards,
some locations could experience heavy rainfall. This wetter
pattern will be short lived as abnormally hot and dry weather is
expected to return during the latter half of the week.
&&
.DISCUSSION...
Today/Tonight...
Latest water vapor imagery and streamline analysis reveal a well-
defined inverted trough across northern Mexico. Ahead of this
system, conditions are considerably cooler and more moist across
the Desert Southwest than they were 24 hours ago. Earlier this
afternoon, surface dewpoints reached the lower 60s across central
Arizona and as high as the lower 70s across the Imperial Valley of
southeastern California. Temperatures across the lower deserts
have also struggled to rise through the lower 100s.
Clouds have been slow to clear across the Phoenix metro area,
likely in response to weak ascent associated with an MCV in the
vicinity of Coconino County. The steering flow is also stronger
than normal between the stubborn Monsoon High across northern New
Mexico and the approaching trough, with 20 kt noted in the KPHX
ACARS soundings. This is yielding 0-6 km shear of 30 kt across
Pinal/Pima Counties. Mesoanalysis indicates some drier air has
worked its way into eastern Arizona. Nevertheless, isolated
convection has already initiated across the White Mountains.
Latest HREF depicts a strong signal for an MCS developing tonight
near the Maricopa/Pinal/Pima triple point, before spreading
westward into southwestern Arizona and ultimately southeastern
California after midnight. Conceptually, this seems reasonable
given the presence of deeper moisture and stronger deep layer
shear closer to the inverted trough. Any cells within this complex
will be capable of producing strong to severe wind gusts, blowing
dust, and localized heavy rain.
Across central Arizona, variability in the CAMs suggests the
forecast is more uncertain. Latest ACARS soundings still show
abundant CIN associated with some drying near 700 mb. Rainfall in
the Valley largely hinges on the development of activity further
upstream across the Mazatzal and Superstition Mountains. There is
some potential for at least isolated activity, per the latest runs
of the HRRR and U of A WRF-GFS. However, latest trends in these
CAMs are not nearly as bullish in these areas and more closely
resemble this morning’s NSSL WRF. One other low-probability
scenario is the organized complex of storms across Pima County
produces an outflow boundary that triggers additional development
further north across the Valley later this evening.
&&
.PREVIOUS DISCUSSION...
For Monday, the inverted trough is forecast to track north
northwestward through the western half of the region, while
moisture levels continue to improve. Depending on the extent of
the convection later today and tonight, Monday may actually be the
better day for showers and storms across eastern and south-central
Arizona. The latest hi-res guidance shows higher instability on
Monday vs today with forecast CAPEs in a 1000-1500 J/kg range
across south-central Arizona to 500-750 J/kg over the eastern
Arizona high terrain. The better quality moisture and higher
instability could result in more widespread storm coverage during
the afternoon across southeast Arizona northward through the
Mogollon Rim as long as there isn`t too much leftover morning
debris cloud to inhibit insolation. This scenario could then
present an optimal pac-man collision of outflows over the Phoenix
area with outflows coming from the Tucson area and from the high
terrain east of Phoenix. Shear will be lower on Monday, but with
the higher CAPE and the possibility of significant outflows
colliding over the south-central Arizona lower deserts, right now
it seems Monday evening may be the best chance for decent rain
over the Phoenix metro. Looking farther west over southwest
Arizona and southeast California on Monday, it very well could be
a fairly quiet day as it seems likely the atmosphere will be
convectively overturned from this evening/early overnight
convection.
By Tuesday, the inverted trough is forecast to have ejected well
to our north with southwesterly flow overtaking the region. This
will result in a gradual drying and likely less shower and
thunderstorm chances on Tuesday with the best focus of convection
likely over the eastern Arizona high terrain. Temperatures should
also be the coolest we have seen since late June with forecast
highs on Monday and Tuesday right around normal readings. The rest
of the coming week will see a resurgence of the sub-tropical high
first across northern Mexico and then into the Desert Southwest
late in the week into next weekend. The positioning of the high to
our south is expected to continue to bring a drying flow during
the latter half of the week with any residual boundary layer
moisture likely getting scoured out. This should nearly completely
end any storm chances, even over the high terrain, starting
Thursday. As the sub-tropical high takes over across the region
again later this week and we dry out, temperatures will also start
climbing to above normal readings. The latest NBM forecast highs
show readings back to around 110 degrees across the lower deserts
during the latter half of the week and possibly back to around
115 degrees for some areas by next weekend.
&&
.AVIATION...Updated at 2350Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
The main concerns over the next few hours will be line of showers
and thunderstorms approaching from the east. The arrival time is
expected by 02Z-03Z at the metro terminals. The best chances for
storms will be between 03Z-05Z as well as gusty northeasterly
winds up to 30-35 kts. Storm chances will wane by 06Z tonight.
Winds are expected to return back to west as activity moves out of
the region with a late easterly shift expected early tomorrow
morning.
Southeast California/Southwest Arizona including KIPL and KBLH:
A complex of thunderstorms is expected to develop across SW AZ and
move west into SE CA late tonight. This activity looks to reach
the TAF sites generally after the 07-08z timeframe where VCTS is
expected with gusty outflows up to 35kts. There is a risk that
visibilities could come down both in blowing dust and heavy
rainfall, something that will be monitored for future updates.
Otherwise, a general SSE wind and SCT/BKN mid to high clouds.
&&
.FIRE WEATHER...
An unsettled weather pattern will be seen over the area through
Monday with much better shower and thunderstorm chances areawide.
Storms today are more likely to be seen across western Maricopa
Co. westward through the Colorado River Valley. For Monday, the
likely best area for storm activity will be across the eastern and
south-central Arizona. Gusty erratic outflow winds are the
greatest concern with these storms, though some beneficial wetting
rainfall is likely for some areas. Minimum afternoon humidity
levels will fall into a 15-25% range today and 20-30% on Monday,
while temperatures fall back closer to normal readings by Monday.
Starting Tuesday, a drying flow will overtake the region bringing
decreasing shower and storm chances. For the latter half of the
week, storm chances will completely come to an end, while
temperatures once again warm to above normal readings. Minimum
humidities later this week will also dip back into a 10-20% range
by Wednesday and possibly even into the single digits by Friday.
&&
.CLIMATE...
Active Streaks:
PHOENIX
1. Consecutive days of high temperatures 110F or greater: longest
on record at 30 days (previous record: 18 days in June 1974)
2. Consecutive days of no measurable precipitation: 4th longest on
record at 129 days
YUMA
1. Consecutive days of low temperatures 85F or greater: 2nd longest
on record at 19 days
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
DISCUSSION...Hirsch
PREVIOUS DISCUSSION...Kuhlman
AVIATION...Salerno
FIRE WEATHER...Kuhlman
AREA FORECAST DISCUSSION
National Weather Service Charleston WV
736 PM EDT Sun Jul 30 2023
.SYNOPSIS...
Isolated showers across the south this afternoon, showers across
the north tonight. Cooler and less humid through mid week.
Another system returns for the end of the work week.
&&
.NEAR TERM /THROUGH MONDAY/...
As of 643 PM Sunday...
Reflected the grids to show current obs. This entails increased
PoPs over our SW Virginia and SE Ohio counties. Showers and
thunderstorms are popping up along a stationary front over
SW Virginia and E Kentucky. Expecting this activity to continue
in Buchanan and Dickenson counties for at least another hour or
two before this front sags a little further south.
Showers and thunderstorms are also spawning to our north due to
a shortwave over N Ohio. This disturbance will continue to drift
southeast and through our area in the overnight hours. Perry
County and even Washington County in Ohio will see some spotty
showers and thunderstorms moving through within the next few
hours. There is some variance in the models, but the RAP and
HRRR agree that precipitation will be likely across the northern
West Virginia lowlands and then the northeastern mountains
overnight.
As of 125 PM Sunday...
Generally fair conditions are expected through the remainder of the
afternoon with only a diurnal cumulus field to contend with. The one
exception will be across SW VA/far S WV where a proximity of a
stalled frontal boundary could yield a few pop-up showers later this
afternoon.
Overnight tonight, a shortwave dropping in from the northwest will
brush by our northern counties with a chance of showers or perhaps a
rumble of thunder. Parcel equilibrium levels are right at the -20C
isotherm, so will include a mention of isolated thunder. Clouds
associated with this shortwave should assist in limiting fog
overnight, but will code at least a patchy fog mention in the
valleys heading into Monday morning.
Monday looks to be another stellar day with afternoon highs across
the lowlands in the low 80s with dew points mid 50s amid a light
northerly wind.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
As of 150 PM Sunday...
A high pressure system will remain over the area for Monday
night through Tuesday night. This will allow for dry weather
with a warm afternoon and unseasonably cool nights.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
As of 1205 PM Sunday...
A surface high pressure system will remain over the area for
Wednesday, providing dry weather.
Models show a disturbance pushing across the area Thursday or
Thursday night, allowing for some showers and thunderstorms.
There is some disagreement between the models on the timing and
amount of moisture available.
Models then show a cold front pushing into the region from the
northwest either Friday or Friday night, providing showers and
thunderstorms. Models continue to differ on the timing of this
front and especially on how quickly it will move south of the
region. Some models hang the front over the region, while
others push it south of the area quicker. Therefore, confidence
in chances of precipitation on Saturday are low.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
As of 728 PM Sunday...
Mainly VFR through the period. An approaching upper level
disturbance will brush by our northern counties tonight
bringing some SHRA or even an isolated TSRA to PKB/CKB/EKN
during the evening/overnight hours(~02Z-10Z). Mid-level clouds
associated with this disturbance coupled with a light northerly
wind should help to keep fog from being too dense tonight.
Protected valleys where skies are clear or any areas that
receive fresh rainfall could still pickup some patchy fog.
Fog formation tonight will largely depend on cloud cover and
how quickly it moves out. That said, confidence is in the middle
as to where and if fog even forms overnight. Any fog that does
form dissipates by ~13Z.
Monday will be another mostly quiet day with FEW-SCT diurnal
cumulus at 040-060.
Winds from the north, 3-8KTs through the period.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z TUESDAY...
FORECAST CONFIDENCE: Medium.
ALTERNATE SCENARIOS: Fog formation tonight will depend on any
light rainfall across the north, and how quickly mid-level
clouds clear out.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 22 23 00 01 02 03 04 05 06 07 08 09
EDT 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
CRW CONSISTENCY H H H H H H H H H H L L
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H L
EKN CONSISTENCY H H H H H H H H H L L M
PKB CONSISTENCY H H H H H H H H H H H M
CKB CONSISTENCY H H H H H H H H H L L M
AFTER 00Z TUESDAY...
IFR possible in valley fog Tuesday morning.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...None.
OH...None.
KY...None.
VA...None.
&&
$$
SYNOPSIS...RPY/JP
NEAR TERM...JP/LTC
SHORT TERM...RPY
LONG TERM...RPY
AVIATION...LTC
Area Forecast Discussion...UPDATED
National Weather Service Shreveport LA
940 PM CDT Sun Jul 30 2023
...New UPDATE...
.UPDATE...
Issued at 931 PM CDT Sun Jul 30 2023
Two areas of convection are ongoing: one in Central Arkansas, and
another in Eastern Kansas/Western Missouri. The Arkansas storms
will likely remain just to the northeast of our CWA. The second
convective complex has a bit better of a chance of reaching us.
However, most of the model guidance suggests it will likely
dissipate just north of our Arkansas counties shortly before
sunrise Monday morning. This seems reasonable given the strong
ridging and aloft across the ArkLaTex. A few storms tried to move
south into Southern Arkansas earlier this evening but fell apart
as they encountered the stronger subsidence. It is worth noting
the HRRR suggests a few lingering showers or storms could brush
Union County AR or our eastern-most parishes of Louisiana Monday
morning. However, confidence in this scenario is quite low, so a
dry forecast will be maintained.
Otherwise, the going forecast for the remainder of tonight appears
to be on track. Some minor updates were made to the hourly
temperatures and dewpoint grids to better follow observed trends.
CN
&&
.SHORT TERM...
(This evening through Monday Night)
Issued at 1235 PM CDT Sun Jul 30 2023
Upper-level ridge across the desert southwest and extending into
Texas and across the ArkLaTex to maintain hot conditions through
the short-term period ending Monday night. High temperatures
ranging from 100 to 105 degrees, combined with dewpoint values in
the upper 60s to mid 70s, will allow for heat index values to
approach or possibly exceed 110 degrees across much of the region
on Monday. For this forecast package, went ahead and extended the
Heat Advisory through Monday into the early hours of Monday
evening. However, will hold off on upgrading to a warning based
on today`s trends and later model runs.
A few high-res models have suggested that isolated to widely
scattered showers and thunderstorms may be possible on the eastern
periphery of the ridge across south Arkansas and north Louisiana
on Monday. Some storms could produce locally heavy rainfall, gusty
winds and small hail. Thus, went ahead and added pop wording to
the grids for these area for Monday afternoon.
Otherwise, stable conditions expected tonight and tomorrow night
with overnight lows in the upper 70s to near 80 degrees and winds
light and variable. /05/
&&
.LONG TERM...
(Tuesday through next Saturday)
Issued at 1235 PM CDT Sun Jul 30 2023
Hot and humid conditions will continue into the upcoming work week
as the pesky upper level ridge settles over the Southern Plains.
Afternoon highs will likely climb into the triple digits over most
of the region daily under mostly sunny to partly cloudy skies. Heat
Advisories will likely continue, as heat indices are expected to
climb above the 105 degree threshold. It`s even possible that some
areas could see indices reach the 110 degree Excessive Heat Warning
criteria. By next weekend, the upper ridge will start to retrograde
back into the SW CONUS. This will allow for rain chances to return,
as seabreeze activity is expected to develop and move into the
region. Also, an upper trough is expected to dig southward across
the Plains, sending a cool front and additional rain chances by the
end of the weekend into the early portions of the following work
week. /20/
&&
.AVIATION...
(00Z TAFS)
Issued at 642 PM CDT Sun Jul 30 2023
VFR conditions should continue to prevail as strong ridging aloft
dominates the region. Winds will also remain somewhat light and
variable throughout the period. Isolated to widely scattered
showers and thunderstorms may develop across portions of the area
after 31/18z. Areal coverage is very uncertain, but Southern
Arkansas and Northern Louisiana are the most likely to be
affected. Therefore, a mention of VCTS was mentioned at KELD and
KMLU late in the period.
CN
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 79 103 80 102 / 0 20 20 10
MLU 77 101 76 100 / 10 20 20 10
DEQ 76 101 75 100 / 0 10 10 0
TXK 78 103 79 100 / 0 20 20 10
ELD 76 98 75 97 / 0 20 20 10
TYR 79 105 80 102 / 0 10 10 10
GGG 78 104 79 102 / 0 10 10 10
LFK 78 105 79 104 / 0 20 20 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...Heat Advisory until 8 PM CDT Monday for ARZ050-051-059>061-
070>073.
LA...Heat Advisory until 8 PM CDT Monday for LAZ001>006-010>014-
017>022.
OK...Heat Advisory until 8 PM CDT Monday for OKZ077.
TX...Heat Advisory until 8 PM CDT Monday for TXZ096-097-108>112-
124>126-136>138-149>153-165>167.
&&
$$
SHORT TERM...09
LONG TERM....24
AVIATION...09
Area Forecast Discussion
National Weather Service Topeka KS
1036 PM CDT Sun Jul 30 2023
.UPDATE...
Issued at 1036 PM CDT Sun Jul 30 2023
We are seeing thunderstorms redevelop across southeastern NE as
the low level jet begins to strengthen. RAP forecast soundings and
objective analysis suggests there is still around 1000 J/kg of
elevated CAPE, and 0-6km bulk shear is around 40KT. So it is not
out of the question for some damaging winds or small hail with the
stronger updrafts. It is questionable how likely damaging winds
are to reach the ground since temps have cooled into the 70s
across northeast KS. But forecast soundings still show decent
downdraft CAPE as well. So we may be looking at round two for
thunderstorms over the next several hours.
UPDATE Issued at 400 PM CDT Sun Jul 30 2023
Elevated thunderstorms are continuing to develop over southeast
NEB. Given the current mid level pattern, these showers should
continue to move southeast into northern parts of the forecast
area through the late afternoon.
Currently they appear to be well elevated and not tapping into
all of the available energy. Objective analysis shows around 2000
J/kg of MLCAPE but there is also still a fair amount of mixed
layer convective inhibition based on RAP forecast soundings. So it
is unclear whether storms will strengthen or not. Bulk shear
around 40KT and the CAPE would support supercell structure and the
risk for damaging winds and large hail, so this is worth keeping
an eye on.
Have increased POPs for the late afternoon and evening hours
across the northern counties. There remains a good signal from the
models for increasing warm air advection around 03Z as the low
level jet strengthens and veers more to the southwest. So if
storms don`t make it in this evening, chances look to improve
overnight.
&&
.DISCUSSION...
Issued at 256 AM CDT Sun Jul 30 2023
Key Messages:
- Morning thunderstorms may impact portions of northeast Kansas
this morning. Isolated updrafts may be marginally severe with
damaging wind gusts being the main hazard.
- Portions of central KS are forecast to see heat indices from 100
to 104 this afternoon and Monday, becoming widespread up to 110 Tuesday
and Wednesday.
Several embedded impulses are noted rounding the upper ridge into
the northern plains this morning. The wave over SD is producing a
small cluster of showers and thunderstorms that may expand and
impact far northeast Kansas later this morning. Mid level lapse
rates are not as poignant compared to yesterday with lesser MUCAPE
on the order of 1000 to 1500 J/KG so there is some uncertainty in
maintenance and/or severity of convection as they enter the CWA in
the 12-14Z time frame. CAMS are still varied on handling this
scenario, however with the latest runs of the GFS, RAP, and HRRR
depicting scattered convection riding along the theta-e axis amid
mid level lapse rates on the order of 7 C/KM, confidence was
moderate enough to add 40-50 pops this morning. Activity exits by
mid day with scattered to broken cloud cover lingering as cooler
high pressure settles into eastern portions of the area. Meanwhile,
southerly sfc flow in closer proximity to the upper ridge across
central Kansas results in a decent gradient in highs today from the
mid 80s in far northeast areas to the upper 90s in north central KS.
Heat indices may flirt close to advisory levels in this area, up to
104.
Upper pattern repeats this evening with an additional embedded wave
developing an MCS off the high plains, more likely impacting far
northeast Kansas Monday morning, based on the placement of the
ridge. Unfortunately could not justify raising pops above 40% as
CAMs remain varied on the coverage and track of these storms.
Environment is characterized by MUCAPE up to 2000 J/KG and effective
shear at 30-40 kts so cannot rule out a few severe storms capable of
damaging wind gusts and small hail.
Upper ridge axis shifts east into the southern plains Monday through
Wednesday, returning the dangerous heat area wide as heat indices
peak from 105 to 110 Tuesday and Wednesday. A stronger frontal
boundary approaches the region on Thursday, which may provide relief
to the north while near and south of I-70 could see another
afternoon of heat indices near 105. NBM maintained slight pops
Monday and Tuesday evenings, however I foresee these being removed if
model trends continue with the northwesterly flow to our east.
Several upper disturbances coming off the Pac Northwest late
Wednesday into the weekend signal several chances for much needed
precip while temperatures drop back closer to normal values in the
upper 80s next weekend.
&&
.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1244 PM CDT Sun Jul 30 2023
VFR conditions are expected to be the rule through much of this
forecast. An isolated high-based thunderstorm is possible through
at least the first few hours of the forecast in modest warm-air
advection. Better chances come late as a convective complex may
work its way southeast out of the northern Plains, with also some
chance for local development in slightly strong WAA. Confidence
is high enough for a PROB30 group at TOP and FOE at this range.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 1 PM Monday to 9 PM CDT Tuesday for KSZ034-
035-037-054-058.
&&
$$
UPDATE...Wolters
DISCUSSION...22
AVIATION...65
Area Forecast Discussion
National Weather Service Tucson AZ
237 PM MST Sun Jul 30 2023
.SYNOPSIS...Hot temperatures again today with scattered showers
and thunderstorms. Some storms will generate strong winds and
locally heavy rain. Monday expect an uptick in storm strength and
coverage with flash flooding possible as well. Temperatures cool
to near normal Monday through Wednesday. Rain chances dwindle
after Tuesday as drier air moves in. Hotter temperatures return
by next weekend.
&&
.DISCUSSION...Early afternoon convection starting near the
mountains and favored locations discussed this morning. The 12Z
KTWC sounding suggests another day with strong convective
potential. Precipitable water near average for late July, coming
in at 1.37 inches. Sfc and MU CAPE near 1.9k, but a little less
shear than recent days. Latest RAP keeping CAPE near or above
those levels while bumping PW up a little from Tucson westward,
even as Cochise county falls toward 3/4 of an inch. The HRRR
continues to show eastern areas struggling with lower surface
dewpoints spreading through Cochise County, currently dropping
into the lower 40s. The most favorable area is still likely be the
T.O. Nation into western Pima County, with an increasing moisture
gradient and weak upper level diffluence ahead of the weakening
inverted trough that`s rotating up from the south. It looks like
Tucson will be on the far eastern edge of the busiest storm
environment. As expected, steering level flows and a sharpening
east/west moisture gradient has seen the outflow propagating from
the Mogollon Rim more oriented toward Pinal County in the evening
hours. However, we`re not ruling out another batch for the greater
Tucson area.
The weakening inverted trough rotating up the western flank of
the high is now over southern Sonora and Chihuahua. This feature
is expected to bring a few showers up from the south early
tomorrow, and could push enough debris cloud into the area to
limit insolation Monday. If that occurs, we may end up with our
first daytime high temperature below 100 at Tucson Airport since
mid June. The dynamics and shear associated with the afore
mentioned impulse will likely enhance both coverage and intensity
of storms Monday afternoon into the early evening hours. With
precipitable water values pushing closer to 1.5 inches, we`ll have
to watch for wet microburst activity with both elevated chances
for severe and localized flash flooding. That is, as long as we
don`t gunk over too much in the morning and struggle to reach a
convective temperature.
Some drying as early as Tuesday afternoon, with weak subsidence
behind the impulse limiting thunderstorm coverage. Additional
drying the second half of the week with well below average
thunderstorm coverage expected as the ridge builds back in from
the east and into a blocking position through southeast Arizona
and northwest Mexico by the end of the week. Both GEFS and ECMWF
thicknesses still support a return to 110+ next Saturday, with the
NBM coming in with 109 and a 41% chance of 110 Friday through
Sunday. It`s not east to hit 110 in August, with only 11 total
110 days all time recorded in Tucson (4 of them in 2020).
Both GEFS and ECMWF 5 day ensemble means still suggest positive
height anomalies over our area through mid August. Something that
even the elevated tropical activity expected off the western
Mexico coast over the next 7 days will have a hard time impacting
(a named storm is expected to form and track south of the Baja
Peninsula this week). It looks like the main story will once
again shift back to record breaking heat.
&&
AVIATION...valid through 01/00Z.
Isolated to scattered SHRA/TSRA, potentially impacting KTUS and
KOLS through 31/05Z. Increased storm coverage and intensity
Monday. Gusty outflow winds to 40+ kts along with VSBY reductions
to 3SM or less are possible with TSRA. Outside of thunderstorm
outflows, afternoon SFC winds will be SELY around 15 kts becoming
light and terrain driven overnight. Aviation discussion not
updated for TAF amendments.
&&
.FIRE WEATHER...Isolated to scattered afternoon and evening showers
and thunderstorms are expected across portions of southeast Arizona
this afternoon with a substantial increase in coverage and rainfall
potential tomorrow afternoon. Storms will be capable of producing
strong, gusty, and erratic outflow winds of 45 mph or higher.
Although sustained 20-foot winds will generally remain under 15 mph
today, gusts to around 25 mph may occur. Temperatures will remain
hot but will be a few degrees cooler today with continued cooling
expected through the middle of the week before warming up again
Wednesday and beyond. Valley min RH readings will generally range
between 15-25% today before increasing to 20-30% for tomorrow and
Tuesday. Conditions gradually dry out by the end of next week with
valley min RH values of 15-25% Wednesday and 10-20% for Thursday and
beyond.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Meyer
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