Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/24/23
Area Forecast Discussion
National Weather Service La Crosse WI
1103 PM CDT Sat Sep 23 2023
.DISCUSSION...(This evening through Saturday)
Issued at 255 PM CDT Sat Sep 23 2023
Key Messages:
- Showers and storms are expected this evening and overnight,
isolated strong to severe storms are possible (5% chance) west
of Highway 52.
- Winds will increase to 20 to 25 mph this evening with gusts as
high as 40 mph west of the Mississippi River.
- Additional showers and storms are expected tomorrow along and
east of the Mississippi River.
The rest of Today and Tonight:
Conditions for the rest of the afternoon will continue to have small
chances for showers and storms as shown in the CAMs with continued
850mb moisture transport in play for the region, however the next
robust chance for precipitation comes in this evening with a linear
complex associated with WAA in the southerly flow ahead of an upper-
level low progressing through the Dakotas. As it progresses into our
CWA it will encounter some difficulties, mainly being no longer
associated to an axis of 1000-2000 J/kg of MLCAPE located over
central Iowa. As a result, expecting the line of storms to weaken
quickly as it enters our CWA. With some respectable 0-3km shear,
decent SRHs, and an enhancing low-level jet of 50-60 kts associated
with the synoptic flow, isolated large hail or a severe criteria
wind gust should not be ruled out. However, with capping noted in
the forecast 23.15z RAP soundings, expecting it will be hard to mix
any higher wind gusts down to the surface in addition to the rapidly
diminishing instability.
With the enhancing synoptic winds and low-level jet this evening,
expecting that surface winds will increase with sustained winds to
be in the 20-25 mph range with gusts upwards of 40 mph west of the
Mississippi River in our flatter, more windy spots across southeast
Minnesota and northeast Iowa. Exactly how high wind gusts end up
getting still appears uncertain with some guidance such as the
23.17z HRRR trying to have gusts a bit higher in the 40-45 mph
range. However, given the low and mid-level WAA setup keeping it
difficult for much mixing to occur, this does not appear likely but
isolated higher gusts are possible. Regardless, wind advisory
issuance does not appear likely at this time with widespread gusts
not expected to reach criteria this evening.
As storms progress eastward overnight, scattered non-severe showers
and storms will overtake the region providing a much needed second
round of decent rainfall in lieu of the good soaking we got last
night. The 23.06 EC ensembles show high chances (70-100% chance) for
seeing over 0.5" of precip through tonight west of the Mississippi
River. The 23.12z HREF 24-hr PMM paints a similar pictures with the
exception of keeping the 0.5" or greater totals further west of US-
52 where the stronger convection will occur. With PWATs being
roughly 200% of normal for this time of year, expecting some fairly
efficient rainmakers with PWATs of around 1.5", however with limited
instability overnight there will not be much strong convection
present which will limit totals to a half an inch or so for many.
Sunday:
Sunday will feature continued chances for showers and non-severe
storms with a continued moisture feed in the southerly cyclonic
flow. This will allow for a narrow feed of weak instability in the
vicinity of the Mississippi River with MLCAPE values in the ballpark
of a few hundred J/kg, with the higher PWATs being slightly lower
but still about 150% of normal. Still could expect some efficient
rain in spite of the low instability with the 23.12z HREF PMM
showing the potential for upwards of 0.25" in spots Sunday
afternoon. Otherwise temperatures will be fairly cool with the
upper-level low in place to the northwest for Sunday keeping our
highs in the upper 60s and lower 70s.
Next Week:
Slight precipitation chances continue into Monday with the lingering
upper-level low to our northwest. Temperatures for Monday will trend
slightly warmer with widespread highs in the lower 70s. As the upper-
level low gets squeezed out of our region, upper-level ridging will
slowly build into our region over the course of the week. There is
some disagreement between the long range guidance as to how much the
ridging amplifies going into late week, regardless generally
expecting a drier forecast for this week with temperatures remaining
seasonable in the middle to upper 70s and gradually warming late-
week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1103 PM CDT Sat Sep 23 2023
A line of showers and scattered storms are expected to develop
along a cold front which will move east through the TAFs
overnight. The best chance for thunderstorms for KRST will be from
24.06z and 24.08z and for KLSE between 24.08z and 24.10z.
In the wake of the cold front, ceilings will become MVFR and
continue into early Sunday afternoon before becoming VFR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
DISCUSSION...Naylor
AVIATION...Boyne
Area Forecast Discussion
National Weather Service Grand Forks ND
1033 PM CDT Sat Sep 23 2023
.UPDATE...
Issued at 1024 PM CDT Sat Sep 23 2023
The main area of rain has shifted into NW and west central MN this
evening. Light showers move WNW along Highway 2 on the ND side.
Showers and isolated thunder will remain possible overnight, with
another band of showers and isolated storms developing tomorrow.
Dry conditions are in sight, but occur early into the work week.
Areas underneath the rain could see brief heavy rain at times.
UPDATE Issued at 618 PM CDT Sat Sep 23 2023
Band of showers and storms are moving through the I-94 corridor
this evening and will continue to shift north over the next
several hours. Visibility reductions and heavy rainfall are
possible in and around the thunderstorms. Looking at a lull in
activity post 9pm in the southern Red River Valley, with scattered
showers lingering overnight. The band of rainfall has been
efficient with producing up to 3 inches of new rainfall as it
moves through. However as it continues to move north, it will
gradually weaken.
&&
.SHORT TERM...(This evening through Sunday night)
Issued at 228 PM CDT Sat Sep 23 2023
Key Messages
-SPC left the southern half of the FA in a marginal risk for
severe weather late this afternoon into early evening
-Widespread rain is expected across the FA tonight, with more
on Sunday
As of mid afternoon, there were still clusters of showers and
storms across the FA. A slightly stronger one was over northeast
South Dakota, lifting north to northwest. There is a lot of
lightning associated with this cluster, but not severe weather.
Think as this cluster lifts north to northwest, it will bring more
shower and storm activity to at least southeast North Dakota. It
is also spreading more cirrus into the southern FA, so it is not
looking like any areas in this FA are going to see much heating
today.
Some clearing/heating has been ongoing across southeast South
Dakota, where temperatures have risen to the mid 70s now, and
there are some breaks of sun. So instability should continue to
build in this area through the late afternoon. A surface low is
also down around Sioux Falls, but is only expected to lift up
toward Brookings/Watertown by 00z tonight. So think the best area
for severe development could be from southwest Minnesota up toward
St. Cloud/Minneapolis. The CAMS which are still showing a QLCS
type line of storms developing along this corridor, have it
already ongoing, which it is not. For what it is worth, the HRRR
has been backing off on that line of storm scenario, and has been
showing more clusters of storms from southwest Minnesota up toward
the Twin Cities. Can`t completely rule out a strong to severe
storm rotating up into our west central Minnesota FA, which would
be in the late afternoon to early evening time frame. However,
most of the UH tracks greater than 75 have shifted east of the FA
now.
More likely, the FA will experience widespread rainfall tonight.
The surface low will eventually become stacked overnight, as the
500mb low lifts up into southeast North Dakota by 12z Sunday.
There is a strong low level jet/warm advection on the east side of
the low, along with a nice upper jet, and good moisture transport.
Don`t believe it will be the entire night, but at least a 2 to 5
hour period of time with pretty steady rain. Moving into Sunday,
the stacked low remains over the FA, so there could be periods of
showers/storms rotating around the low throughout the day. This
activity will linger into Sunday night, especially along and east
of the Valley.
.LONG TERM...(Monday through Saturday)
Issued at 228 PM CDT Sat Sep 23 2023
Persistent upper ridging over the southern Hudson Bay area will
stall the upper low over northern Minnesota with it eventually
getting trapped under the ridge with ridging building out of the
rockies ahead of the next large scale pacific trough. With the
stalling upper low rain lingers into the early part of the week
before it gets ejected around the base of the ridge through the
great lakes. With a much drier profile from H500-H700 rounding the
ridge and the addition of low level cold air advection behind the
occluded low, precip will wind down by Tuesday with 24 hour NBM 50th
probs placing an additional 0.01-0.10" by Tuesday morning in our MN
counties.
The incoming ridge bring a return to near normal highs in the upper
60s to lower 70s through the week per the NBM 25th percentile. Late
in the week approaching Pacific troughing will increase chances for
shortwave activity cresting the ridge thus increasing chances for
precip, although with little agreement from cluster analysis on the
strength of the ridge past Thursday confidence remains low. Possible
impacts through the period remain harvest operations with the
lasting rain while frost is a low probability with the NBM 10th
percentile for min temps not dipping past the low 40s.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1024 PM CDT Sat Sep 23 2023
Rain with embedded thunderstorms are times continues to move
across west central MN and along the Highway 2 corridor. Rain and
VCTS are possible for TVF, GFK, and BJI through 10-12z. Other
areas could see VCSH through the overnight period as the main area
of rain has moved further into MN. Another band of showers is
expected to develop in the southern Red River Valley during the
late morning and early afternoon and track north. FAR will see the
showers and isolated storms first around 18-20z. Ceilings will
drift between MVFR and IFR through the TAF period, but improve
near the end of the TAF period starting from the west and
gradually moving east ward. Otherwise, rain chances will start to
diminish late tomorrow afternoon in DVL and work its way east
through the remainder of the TAF period and beyond.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...Spender
SHORT TERM...Godon
LONG TERM...TT
AVIATION...Spender
Area Forecast Discussion
National Weather Service Fort Worth TX
643 PM CDT Sat Sep 23 2023
...New Aviation, Short Term...
.SHORT TERM... /NEW/
Update:
No major changes to the forecast through Sunday night. We`re still
watching a small area of focused low level convergence along and
ahead of a dryline bulge near Wichita Falls this evening. Latest
satellite imagery shows a small cumulus field bubbling in this
area, but latest RAP objective analysis indicates modest
inhibition remains. Water vapor imagery shows a slightly better
mid and upper level moisture feed into this area which may
indicate the presence of at least some modest mid level forcing
for ascent, so it remains to be seen if this will be sufficient
for a few storms to develop or not. We`ll maintain some very low
PoPs right along the Red River to account for this potential.
Otherwise, we`ll be watching the ongoing convection across the
eastern half of Oklahoma as it eventually organizes into a cluster
and spreads south into the Arklatex. This should clip our
northeast counties after midnight and may linger into the early
morning hours Sunday across our far eastern counties. Later in the
day, a cold front will sag south into North Texas and will become
the primary focus for thunderstorm development during the
afternoon. At this time, we think late afternoon into the evening
will be the main timing for the front to initiate convection,
however, any strong residual outflow boundaries from morning
storms could trigger some development well before then. Any storms
that develop on Sunday could be severe with large hail and
damaging winds being the primary threats.
Until storms develop, it`ll be another hot day with high
temperatures pushing 100 degrees again. Heat indices will again be
above 105 but cloud cover may limit heating in some areas. Given
some uncertainty in this, we`ve left the heat advisory alone at
this time. No other changes made as of this evening.
Dunn
Previous Discussion:
/This Afternoon through Sunday Night/
Water vapor imagery shows a stream of moisture around the
periphery of stronger mid level ridging across Central and South
Texas. This ridging should keep a lid on most convective activity
in our area this afternoon and allow temperatures to soar into the
upper 90s and low 100s. On top of that, low level moisture will be
difficult to mix out and dewpoints should remain in the upper 60s
during peak heating. This will result in heat indices between 105
and 110 degrees...therefore the heat advisory will remain in
effect.
At the surface, an elongated area of low pressure extends
throughout the Plains with a cold front expected to spread
southward later today. This is in response to a potent shortwave
racing across the Northern Plains. While the front will remain
north of our area today, a weak dryline will be in place across
our northwest counties. Focused convergence along this feature
could be sufficient for an isolate storm or two to develop during
peak heating, but coverage is expected to remain slim and we`ll
keep PoPs less than 10%.
Meanwhile, tonight, thunderstorms are expected to develop along
the frontal boundary well to our north across Oklahoma and these
will spread southward during the late overnight hours. A modest
low level jet will develop across North Texas and should veer
into the southeast moving complex. This may tend to allow the
storms to turn a little more southerly with time and we`ll have
some respectable PoPs across our northeast counties to account for
this. While there will be some potential for severe storms, the
overall complex should be in a weakening stage by this time.
Strong outflow winds would be the main concern along with locally
heavy rainfall.
On Sunday, the cold front will make steady southward progress into
our area and should be somewhere northwest of the Metroplex by
early afternoon. A trailing shortwave trough will spread through
the Southern Plains during this time and should provide additional
forcing for ascent atop the frontal zone. With another hot and
humid day expected, thunderstorms should develop along the frontal
boundary by late afternoon and spread south into the late evening
hours. There is a little uncertainty with respect to where the
boundary will be located when thunderstorms develop and for now
we`ve broadbrushed some higher PoPs into the evening hours. These
will continue to be refined with time. Any storms that develop on
Sunday will have the potential to be severe with mainly a damaging
wind and hail threat.
Dunn
&&
.LONG TERM... /Issued 223 PM CDT Sat Sep 23 2023/
/Monday Morning Through Next Week/
A cold front that has been advertised over the past several days
will already be passing through the area on Monday morning. As the
front drapes southward, increased chances for showers and storms
(generally 60 to 70%) will remain in the forecast along and ahead
of the boundary. By this point in the forecast, the atmosphere
will likely be overworked because of prior activity across North
Texas on Sunday afternoon and evening. This will limit widespread
strong to severe thunderstorms across Central Texas, but isolated
instances of severe weather will remain possible ahead of the
front due to marginal ascent and weaker deep layer shear. That
being said, some thunderstorms will still have a low threat for
hail and damaging winds as we move into Monday afternoon. Before
the front clears our southern zones, it is expected to slow down
and stall out. This will keep the potential for showers and
thunderstorms in the forecast across portions of Central Texas
overnight Monday through Tuesday afternoon before the front
finally departs from our area.
When all is said and done, storm total accumulations are expected
to range anywhere from 0.50 inches along and west of the I-35
corridor and into the Big Country to upwards of 2.00 inches along
our northeastern counties. Locally higher amounts will also be
possible, but because of lingering drought conditions across North
and Central Texas, widespread flood issues remain unlikely at
this time. Despite this however, minor nuisance flooding and
isolated instances of flash flooding will be possible, especially
in those areas across our northeast that have received rainfall
recently.
Seasonably warm and drier conditions will prevail in the wake of
this early week system, though an upper-level ridge is expected to
build back in as we close out the month of September. Slightly
above normal temperatures will continue with highs in the upper
80s and into the low 90s as we move toward the end of the week.
Reeves
&&
.AVIATION... /NEW/
/00Z TAFs/
VFR will prevail with south flow 10 to 20 kt overnight and into
Sunday. The main concern through the period will be a cold front
entering North Texas and developing thunderstorms by Sunday
afternoon. Timing is a little uncertain, but we`ll delay the VCTS
until 23Z based on the latest guidance and continue TS into the
late evening hours. It`s likely that a TEMPO or prevailing TS will
be needed at some point, but we`ll wait until we get a better
handle on timing. North flow will commence behind the front and
thunderstorm activity on Sunday night into early Monday.
Dunn
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 80 99 72 88 70 / 10 30 80 40 10
Waco 78 99 72 88 69 / 10 20 70 70 30
Paris 74 86 68 83 65 / 50 50 90 50 10
Denton 78 98 70 88 65 / 10 30 70 30 10
McKinney 77 96 70 86 66 / 20 30 80 40 10
Dallas 80 99 72 88 70 / 10 30 80 40 10
Terrell 77 96 70 85 67 / 10 30 90 60 20
Corsicana 79 97 73 88 70 / 5 30 80 70 20
Temple 77 98 72 91 69 / 5 20 60 70 40
Mineral Wells 77 99 71 91 66 / 10 30 60 40 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 7 PM CDT Sunday for TXZ091>094-100>105-
115>121-129>134-141>146-156>161-174-175.
&&
$$
Area Forecast Discussion
National Weather Service Gray ME
1038 PM EDT Sat Sep 23 2023
.SYNOPSIS...
High pressure remains largely in control over northern New
England through much of this upcoming week. Some showers from
the northern fringe of Ophelia may clip far southern areas at
times tonight into Sunday night. The remnants of Ophelia exit
into the Atlantic Monday with high pressure becoming centered
over New England through the middle of next week.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
1035 PM...POPs were mainly adjusted to capture current radar
trend and adjust them forward over the next few few hours. Based
on current T/Td and the trend, have raised mins by a degree or
two again, with mid to upper 40s in the N and low 50s in the S.
750 PM...Fine tuned the POPs and nature of the SHRA overnight
across the S areas. HRRR shows showers trying to push N into srn
NH for the rest of the evening, but only making it into souther
counties, and this is where some likely POPs have been added,
although amounts will be only a few hundredths of an inch in
most spots. Brought the slt chc POPs further N, following the
HRRR with weaken band of showers maybe producing some sprinkles
into the NH lakes region and into the ME coastal plain later
tonight. Also, adjusted temps a bit. Given the thicker cirrus
deck, even in the N, not sure rad cooling will be as good as
last night, so mins were bumped up a degree or two in many
spots.
Previously...Sprinkles have moved into extreme southern New
Hampshire, but elsewhere the drier air being supplied by the
building high pressure center to the north continues to erode
the northern edge of the rain and keep conditions dry. Clouds
steadily thicken with southward progress, and these trends are
expected to continue through the overnight hours. Clearer skies
up north have allowed temperatures to warm more today, and will
also allow temps to cool the most tonight. Valley fog is
expected again tonight across the north, as well as through the
CT River Valley.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Conditions remain quite similar tomorrow, with a few sprinkles
and showers across southern areas through the day, with brighter
and warmer conditions north. Waves along the coastline increase
during the day tomorrow to around 4 ft, bringing an increase to
the rip current risk. At this point the periods look short
enough that the risk only rises to moderate, but will still be
an increased threat for any swimmers tomorrow.
The pattern continues tomorrow night, with a few light showers
across southern areas, and clearer skies thanks to high pressure
across the north. Cloud cover looks to be a little thicker
across southern and central areas tomorrow night, so lows likely
won`t dip as much as they will tonight.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
Dry and mild weather looks to be the norm for much of this
upcoming week as most deterministic and ensemble guidance agree
that ridging will remain put. There may be a few exiting brief
showers early monday morning across southernmost NH but that`s
it for PoPs during the extended. With high pressure in place
we`ll expect warm days with plenty of sun along with clear cool
nights with good radiational cooling. This will mean valley fog
late at night and early mornings much of the week. Looking even
further ahead, not sure when the next chance of substantial
rain will even be as ridging continues to get stronger as per
most ensemble data.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
Short Term...Mainly VFR conditions prevail through tomorrow
night, with some exceptions. Nighttime valley fog is likely at
LEB and HIE again tonight, and possible tomorrow night. MVFR
ceilings are possible later tonight across far southern New
Hampshire, and would then linger through at least tomorrow
morning.
Long Term...Northeasterly gusts to around 20 kts will be possible
for coastal TAF sites Monday into Tuesday morning. Conditions will
remain VFR for much of next week, other than night time valley fog
likely bringing restrictions.
&&
.MARINE...
Short Term...High pressure remains parked north of the waters
as Tropical Storm Ophelia moves through the Mid Atlantic. A
shorter period swell from the interaction between the two
systems arrives tomorrow afternoon, with seas building close the
SCA levels. These continue through tomorrow night as a
northeasterly breeze remains near 20kts.
Long Term...Northeasterly flow between high pressure over eastern
Canada and the remnants of Ophelia passing south of New England
could bring wind gusts to around 25 kts Monday into Monday night.
High pressure then settles over New England through the middle of
next week with winds and seas remaining below SCA thresholds.
&&
.TIDES/COASTAL FLOODING...
Distant Ophelia will allow for increasing swells across our
waters Sunday and Monday which will allow for an increased
threat for strong rip currents.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.
&&
$$
SYNOPSIS...
NEAR TERM...Cempa/Clair
SHORT TERM...Clair
LONG TERM...Ekster
AVIATION...
MARINE...
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
920 PM EDT Sat Sep 23 2023
.SYNOPSIS...
High pressure and a dry airmass will remain in place across the
region through the weekend. Chances for rain will increase into
mid week next week as an upper level low moves southeast into
the Great Lakes and Ohio Valley.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Latest guidance has shown more cloud coverage encroaching on the
middle Ohio Valley late tonight into tomorrow. While blended
guidance continues to suggest scattered clouds, latest satellite
trends lean toward a sharp cutoff between mostly clear skies and
mostly cloudy to overcast coverage. Have used time-lapsed RAP
guidance to nudge sky coverage grids in this direction.
Otherwise, steady, but light northeast winds will continue
through the night with cool temperatures in the 50 to 55 range
by morning.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
The remnants of Tropical Storm Ophelia will lift north across
the mid Atlantic States Sunday into Sunday night with the clouds
associated with it generally remaining off to our east. Mid
level ridging will be in place across the mid Ohio Valley
through the day on Sunday before it begins to slowly break down
Sunday night. This will lead to mostly sunny skies through the
day on Sunday with some increasing clouds Sunday night. Highs
on Sunday will be in the 75 to 80 degree range with lows Sunday
night mostly in the 50s.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
Story lines remain the same for this week`s much needed
rainfall chances. While these chances are largely driven by the
evolution of the mid-level low south of the Hudson Bay ridge, a
shortwave exiting the southwest CONUS this weekend, will provide
another source for lift Monday night through Tuesday. Chances
increase Tuesday night through Wednesday night as the closed low
over the Midwest shifts southeastward into the lower Great
Lakes and Ohio Valley regions. Chances trend downward late in
the week, as the low shifts eastward, placing the region in
drier northeasterly mid-level flow.
Due to the chances for showers and the expected widespread cloud
cover, afternoon temperatures are lowest on Wednesday and Thursday.
As the forecast nears, these values may trend downward if confidence
in shower activity increases. Generally expecting amounts to be
fairly limited across the entire area, however, there is potential
for slow moving showers. This should allow for at least a localized
potential for higher rainfall amounts of 1-2".
Regarding the forecast confidence, it`s important to note that while
there are larger features which appear to modeled well leading to
mentions of rainfall throughout the period, the smaller features
will be very important to iron out as the days draw closer. WPC
cluster analysis suggests there are still drier solutions that are
more than possible. As a result, expect rainfall probabilities to
continue to be adjusted throughout the weekend and into early next
week.
&&
.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
Still maintain VFR conditions through the taf period. However,
some lower CIGs will work their way across KCMH/KLCK late
tonight and persist through most of the daylight hours Sunday.
Coverage in these CIGs remains uncertain, but certainly possible
for an MVFR reduction at those terminals. For the remaining taf
sites, expecting mainly cirrus clouds through the taf period.
Wind direction remains from the northeast below 10 kts.
OUTLOOK...MVFR conditions possible Tuesday into Wednesday.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...Hickman
NEAR TERM...
SHORT TERM...JGL
LONG TERM...McGinnis
AVIATION...Clark
Area Forecast Discussion
National Weather Service Memphis TN
835 PM CDT Sat Sep 23 2023
...New UPDATE...
.UPDATE...
Issued at 827 PM CDT Sat Sep 23 2023
Currently, a line of showers and storms extends from southwest
Missouri into northeast Oklahoma. As this line propagates east
over the next few hours, significant weakening is expected as it
approaches the Mid-South. The 00Z HRRR depicts areas along and
west of the Mississippi River seeing the best chance of showers by
morning. Additional shower and thunderstorm development is
expected Sunday afternoon, with the bulk of activity confined to
areas around the Mississippi River.
Outside of showers and thunderstorms, temperatures across the
Mid-South will be near-normal for the beginning of the week with
afternoon highs in the low to mid 80s through Wednesday.
ANS
&&
.SYNOPSIS...
Issued at 241 PM CDT Sat Sep 23 2023
Showers and thunderstorms over the central and southern plains
will move into Arkansas tonight and gradually weaken toward
morning. Additional showers and thunderstorms will develop over
the Midsouth Sunday afternoon, with most of the activity along
and west of the Mississippi River. An upper level disturbance
will move slowly through the Midsouth Sunday night into Monday. A
weak surface cold front will interact with warm and humid
conditions to bring additional scattered showers and thunderstorms
through early Tuesday.
A building upper level high pressure ridge will bring dry and warm
conditions to the Midsouth in the mid to late part of next week.
&&
.DISCUSSION...
(This evening through next Friday)
Issued at 241 PM CDT Sat Sep 23 2023
The Midsouth remains under the influence of a sharp upper level
ridge this afternoon. This ridge extends from northern Mexico
into the Great Lakes. East of the ridge, Tropical Storm Ophelia`s
remnant low is tracking up the mid-Atlantic seaboard, while to the
northwest, a closed upper low over SD was moving slowly east. An
associated upper trough axis extending from this low will lift
through the central plains tonight. Moderate instability ahead of
this feature will support thunderstorms and an Enhanced Risk of
severe storms in an area from Tulsa to Kansas City to Joplin. This
convection will take a southeast turn toward the Arklamiss
overnight, roughly along the midlevel thickness gradient. Some of
the convection will likely enter eastern AR toward daybreak, but
will likely have weakened significantly.
Another open upper level trough will track from the central
plains into the Midsouth Sunday night into Monday. This feature
will likely bring the greatest rain chance to the Midsouth, aided
by mid 60s surface dewpoints and PWATs near 2 inches.
From Monday night through midweek, the upper low over the upper
Midwest will pass through the Great Lakes, taking a more northerly
and progressive track than predicted by yesterday`s models. This
will allow a 589dm 500mb ridge to move into the lower and middle
MS River Valley by Friday. For the Midsouth, midweek rain chances
near the TN River are lower, relative to earlier forecasts, while
late week temps across the Midsouth are a few degrees warmer.
Given the amplification of this ridge depicted in the GFS and
ECMWF ensembles, future NBM guidance for late next week may be
warmer still.
PWB
&&
.AVIATION...
(00Z TAFS)
Issued at 616 PM CDT Sat Sep 23 2023
Short term models keep currently the developing MCS well west of
the Mid-South overnight. Some showers are possible across western
sections of the Mid-South Sunday afternoon. Have included VCSH at
KJBR for Sunday afternoon. VFR conditions will continue through
the forecast period. Winds will be light and mainly from the
southeast for much of the forecast period.
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
UPDATE...ANS
PUBLIC FORECAST...PWB
AVIATION...ARS
Area Forecast Discussion...UPDATED
National Weather Service Reno NV
852 PM PDT Sat Sep 23 2023
.UPDATE...
The Quarry Wildfire on the west slope of the Sierra about 75 miles
due south of Lake Tahoe became a bit more active this evening
with webcams showing a decent plume earlier this evening. Air
quality sensors have begun to show a worsening of air quality in
the Tahoe Basin and far western NV with HRRR and other high
resolution simulations indicating smoke continuing to advect into
the area for the next few hours. Given we will be decoupling,
what smoke gets trapped will remain with us until later in the
morning Sunday when mixing will begin to disperse the smoke and
haze. If the fire remains active Sunday, additional smoke will
likely reach over into these areas once again in the evening. We
have updated the forecast through Sunday morning to reflect these
latest trends. Hohmann
&&
.PREVIOUS DISCUSSION... /issued 231 PM PDT Sat Sep 23 2023/
SYNOPSIS...
Dry and seasonable weather will prevail through the weekend before
gusty winds and chances for showers arrive early next week across
northeast California. Areas of critical fire weather conditions
will be possible in areas of receptive fuels across portions of NE
CA and NW NV Monday afternoon. Drier conditions return through
mid-week before the next shortwave trough arrives around Thursday
which could yield another round of gusty winds, showers, and
cooler temperatures into next weekend.
DISCUSSION...
Cool mornings, seasonable high temperatures, and west breezes will
continue through the balance of the weekend before changes arrive
early next week as an eastern Pacific low approaches the region.
For this afternoon, look for highs to reach into the upper 70s
across western Nevada today and Sunday while Sierra valleys reach
into the mid-60s. While morning lows will also be near average for
most areas, colder Sierra valleys may dip as much as 4-8 degrees
below average with lows in the mid 20s. Western Nevada valleys
will see upper 30s to lower 40s Sunday morning.
The first hint of changes will arrive on Sunday in the form of
increasing high clouds across the region as the E.Pac low nears the
west coast. While temperatures will largely be the same as
Saturday, we will begin to see an uptick in southwesterly breezes
Sunday afternoon with gusts reaching into the 20-30 mph range with
Sierra ridgetops gusting 40-50 mph.
Winds will continue to ramp up through Monday with gusty conditions
spreading along the northern Sierra and far western Nevada. Gusts
could reach into the 30-40 mph range Monday afternoon. This may
result in recreational impacts with choppy conditions across area
lakes and also cross winds for high profile vehicles.
The combination of dry conditions and gusty conditions may also
yield critical fire weather conditions across portions of NE
California and NW Nevada Monday afternoon. Main fire weather
concerns will focus across eastern portions Lassen County, far
northern Washoe County, and the Surprise Valley. Gusts could reach
into the 35-45 mph range in these parts with minimum RH of
15-20%. Any areas of critical fuels could see an elevated fire
weather threat as a result.
After the winds diminish Monday evening, light showers will push
into NE CA/NW NV Monday night into Tuesday (25-50% chance). Rain
accumulations in these parts will be on the lighter side with a
few hundredths to a tenth of an inch possible. Far western
portions of Lassen County could receive higher totals with about a
40% chance of up to 0.25".
Drier conditions and lighter breezes will return Tuesday through
Wednesday before the next shortwave trough swings across the
Pacific Northwest late Wednesday into Thursdays. This could push a
frontal boundary across the region with an additional increase in
winds and chances for precipitation as the front moves through.
While uncertainty exists in the exact trajectory of this next
system, there is increasing confidence a cooler and breezier
period for the second half of next week. Fuentes
AVIATION...
VFR conditions will prevail through the weekend outside of areas of
FZFG around KTRK once again early Sunday morning. More unsettled
weather is expected late Sunday into early next week with enhanced
breezes, periods of LLWS and mountain wave turbulence over the
Sierra. Increased chances (25-50%) for rain showers along the Sierra
from northeast CA down to KTVL and a 15-20% chance over the Sierra
Front. Fuentes/Justin
&&
.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&
$$
Area Forecast Discussion
National Weather Service Springfield MO
655 PM CDT Sat Sep 23 2023
Key Messages:
1. Severe threat to ramp up this evening as storms develop over
Kansas and move eastward into Missouri overnight. Initial threat
to be hail to the size of tennis balls transitioning to a damaging
wind threat eastward to Highway 63 after midnight. The threat for
tornadoes remains conditional.
2. Heavy rainfall is also a threat tonight. A Flood Watch has
been expanded over far southwest Missouri...with locally heavy
rainfall of 3 to 6 inches possible.
3. Rainfall to diminish Sunday morning as a cold front slowly
clears the region...then it will be dry into next weekend with
near normal highs around 80 and lows around 60.
.SHORT TERM...(This evening through Sunday)
Issued at 230 PM CDT Sat Sep 23 2023
Morning convection which developed within an axis of higher
precipital water and coincident with 925-850 thermal advection
supported by a strong low level jet has largely stayed north of the
SGF CWA. Thunderstorms have continued to develop within the
moisture axis with only minor propagation eastward which has
limited the severe threat over the northern portion of the
forecast area.
Water vapor depicts a well defined wave/closed low over western
South Dakota which will lead to increasing upper diffluence into
this evening...and a north-south orientated cold front extending
southward from the low bisecting Kansas to a surface low near
Woodward, OK. Thunderstorm development is expected over eastern
Kansas as the influence of the upper system and surface front come
together.
Model soundings closer to the Missouri/Kansas border yield an
atmosphere containing 2500-3000 MLCAPE with just a touch of surface
CIN. 0-3KM helicities exceeding 300 will support rotating updrafts
with the CIN expected to keep the tornado threat minimized but
still possible. This will lead to a large hail to the size of
tennis balls as the initial primary threat (generally outlined by
the SPC Enhanced Threat) though the expectations is for the system
to grow into a line over southwest Missouri into the eastern
Ozarks. The 12z KTOP sounding depicted dry air above H7 with
Downward CAPE of over 1400 Joules (increasing to over 1600 Joules
over Oklahoma)to lead to damaging winds as the line forms. This
will further limit the tornado threat by increasing the magnitude
of the RFD.
As the system transitions it will encounter the axis of strong low
level southerly flow and increasing moisture. The 12z HRRR depicts a
moist sounding to around 600 mb with a dry layer aloft yielding a
precipital water to near 2 inches and still over 3000 MLCAPE over
far southwest Missouri. Morning CAMS models continue to depict
varying solutions, though some have picked up on hourly rain rates
over an inch. Thus the potential for flooding exists as the line
is initially parallel to the moisture axis then evolves to cross
boundary flow as the front is slowed by a wave along the above
mentioned cold front. Have extended the Flood Watch a bit
eastward tonight where confidence is the highest in training
storms.
Scattered showers and possibly a few thunderstorms may then
develop along the front on Sunday before it completes its passage
through the forecast area.
.LONG TERM...(Sunday Night through Saturday)
Issued at 208 PM CDT Sat Sep 23 2023
In the wake of the front the region will find itself in weak
northwest flow through midweek that will set up a prolonged period
of climatologically "normal" weather for late September with high
temperatures in the upper 70s to near 80 and lows in the upper
50s to near 60.
The forecast period will end with an upper ridge building
northward into the Central Plains that will result in rising
heights and warming temperatures.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 630 PM CDT Sat Sep 23 2023
Numerous thunderstorms, with some being severe, are currently
ongoing across western MO. Current anticipation is that new storms
will form in a NE-SW oriented line along and west of the
SW MO/KS border this evening. Initially these storms will be
scattered with possible hazards of large hail up to 1-2 inches and
wind gusts up to 50 kts. These storms are expected to congeal
into a line, possessing 50 kt wind gusts as the dominant hazard,
and progress ESE into southwest MO impacting all TAF sites
throughout the night (generally within the 01-06Z timeframe). High
confidence that ceilings and visibilities are expected to
decrease to at least MVFR with these storms. Medium confidence
that abundant moisture leading to intense rain rates could
potentially reduce visibilities to IFR. Additionally, winds will
likely be strong beneath these storms and largely shifting to out
of the NW with storm passage before returning back to the
background flow of 5-10 kt SE winds. Will mention that the severe
threat is lowest for BBG, but thunderstorms with high rain rates
and some high wind gusts can still be expected.
Remnant stratiform rain with embedded thunderstorms may be ongoing
through Sunday morning but these are expected to clear out by
midday at the latest. Skies will be broken with ceilings between
5-10 kft and winds will be 5-10 kts out of the SSE before a fropa
will shift winds out of the N between 15-21Z. Have included a
PROB30 for additional isolated thunderstorm development along this
front, though confidence is currently low on coverage.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...Flood Watch through Sunday morning for MOZ077-088-089-093>095-
101>104.
KS...Flood Watch through Sunday morning for KSZ101.
&&
$$
SHORT TERM...Runnels
LONG TERM...Runnels
AVIATION...Price
Area Forecast Discussion
National Weather Service Salt Lake City UT
317 PM MDT Sat Sep 23 2023
.SYNOPSIS...High pressure will build over the area through the
weekend, kicking off a warming and drying trend area-wide. The
ridge will begin to shift east early next week, but dry
conditions will continue under southwest flow aloft until the
arrival of the next storm system by the weekend.
&&
.SHORT TERM (Through 12Z Monday)...With split flow in the upper
levels and a modest shortwave trough in the mid levels, seeing
continued active weather across southern Utah this afternoon, with
height rises across northern Utah and southwest Wyoming leading to
subsidence and quiet weather across that portion of the forecast
area.
Satellite and radar both slow a tight mesoscale surface low with
mid and high cloud spreading north through Beaver and Millard
counties as the feature shifts slowly to the northeast. The latest
HRRR is reasonably in-line with this analysis, though
precipitation intensity appears considerably overforecast by the
HRRR at this time given that observations show < 0.1" in 3 hours
across the recently impacted areas. Still watching sensitive
regions of far southern Utah for any flood potential this evening
should a more potent convective shower develop embedded within the
stratiform.
Dry conditions set in area-wide for Sunday with temperatures
rebounding to seasonal normals. Temps will begin a day-over-day
climb as the northern branch of the split flow and ridging begin
to dominate with building high pressure at the surface and broad
subsidence aloft.
.LONG TERM (After 12Z Monday)...High pressure will be in control
across Utah and southwest Wyoming next week. Temperatures are
forecast a few degrees above climate normals through mid-week with
dry conditions. The first hints of a change in the weather pattern
arrives Thursday. A broad low pressure trough over the Pacific
Northwest is forecast to begin digging southward by this time. The
strength of this trough does vary between cluster means with some
even closing off the trough into a closed low. A frontal boundary is
expected to accompany this low which will bring cooler temperatures
in its wake late week; look for seasonal temperatures by the end of
the week and over the weekend as a result. At this time, there is
some moisture associated with the low but it is by no means copious.
As such, rain showers are possible late week across northern Utah
and southwest Wyoming. Southern Utah is expected to remain dry
through Saturday.
&&
.AVIATION...KSLC...VFR conditions will prevail under continued quiet
weather and clear skies. Light northerly flow takes us into the
overnight hours before southerly flow returns by 04Z under clear
skies.
.REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions expected area-
wide as a quiet day is expected outside of some lingering showers in
far southern Utah. Outside of any rogue wind gusts from showers,
diurnal winds are expected under mostly clear skies.
&&
.FIRE WEATHER...Unsettled weather across southern Utah will end late
this evening as an area of low pressure departs to the east.
Behind it, expecting a strengthening ridge to build in, bringing
high pressure to the region for the weekend and early next week.
This will allow for warming and drying across the area, with
daytime minimum relative humidities across the state ranging from
the mid teens in low lying areas to mid 20-30s in the mountains.
That said, expecting overnight recoveries to be quite good for most
areas except perhaps the far southwestern corner of UT across the
Mojave.
Little of concern in the forecast, with temperatures peaking on
Tuesday and relatively light winds throughout the forecast period.
By Thursday, an approaching low pressure system will likely lead
to increased winds across the state, with gusts up to 35 mph
across the West Desert and eastern valleys. Friday morning brings
the next potential moist and cold storm system for the region.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...None.
WY...None.
&&
$$
Wessler/NDeSmet/Selbig
For more information from NOAA`s National Weather Service visit...
http://weather.gov/saltlakecity