Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/05/24
AREA FORECAST DISCUSSION
National Weather Service Albany NY
1020 PM EDT Sat May 4 2024
.SYNOPSIS...
As a storm system approaches from the west, rain will overspread
the area late tonight and continue through much of the day on
Sunday, with much cooler temperatures. Clouds will break for
some sun on Monday with milder temperatures returning to the
region. Warm and sunny weather is expected on Tuesday before the
threat for showers returns to the region for Wednesday and into
the latter portion of the week.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
.UPDATE...As of 1020 PM EDT, light rain showers and overcast
skies are moving into the region from the southwest, although
surface dewpoint depressions greater than 10 degrees persist
outside of the southern Mid-Hudson Valley and eastern Catskills;
even Poughkeepsie ASOS is still reporting an 11F dewpoint
depression as of 10 PM EDT. As the column saturates, light
precipitation will begin to reach the ground through the
overnight period and will continue for much of the day on Sunday
resulting in a soaking rain for most of the region. With only
minor updates made to the arrival time of rain showers
overnight, the forecast remains largely on track; see previous
discussion below...
.PREV DISCUSSION [0730 PM EDT]...At the surface, high pressure
(around 1030 hpa) is exiting off the coast of Maine and will
continue to slowly depart off to the east tonight. Meanwhile, a
slow moving frontal boundary is located over the Upper Midwest
and Great Lakes and it will be heading towards the area for
tonight into Sunday.
Visible satellite shows a mostly cloudy sky over the region,
with the most breaks for far southern areas. Skies will continue
to be mostly cloudy through the evening with some occasional
breaks, but sky cover will start to lower and thicken for
tonight as the storm system approaches from the west.
A few light sprinkles and brief showers can be seen on radar
across central New York, with a few of these already sneaking
into the Adirondacks. Through the evening hours, a brief shower
can`t be ruled out for western areas, but most of the area will
be staying dry this evening, as the best forcing continues to
remain off to the west.
As the ridge axis continues to depart off to the east tonight,
warm advection thanks a southerly low level jet around 30 kts
will allow for a period of fairly steady rain showers to spread
towards the area for the late night hours. 18z HRRR suggest
this will be spreading across southern and western areas after
midnight and expanding northeast across the area for the late
night hours. Rainfall looks fairly light in intensity overall,
but all areas will be see rainfall by daybreak, with up to a
quarter inch of rainfall occurring by sunrise Sunday. Southerly
winds will be starting to pick up by the late night as well,
especially in the larger north-south valleys.
After another mild and comfortable day, temps will drop this
evening and will continue to fall for tonight with the rain
spreading into the area. Most areas will see lows in the mid to
upper 40s (some spots may bottom out right around 50).
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
As the frontal boundary slowly approaches from the west, most of
Sunday looks to be fairly wet and damp with periods of showers
through the entire day, with the steadiest and heaviest rainfall
across northern and western areas. Temps will be held down and
steady due to the persistent clouds and precip, with most spots
being held into the lower to middle 50s through the day.
Overall, additional precip on Sunday will be one third to two
thirds of an inch of rainfall. While this won`t be enough to
cause any hydro issues (especially within greenup starting to
occur), it still make for some wet and soggy conditions
outdoors.
Although the steadiest precip will be done for Sunday evening,
some showers may still linger into Sunday night as the main
frontal boundary crosses the area from west to east overnight.
Otherwise, it will remain cloudy and damp with some patchy fog
and temps in the upper 40s.
On Monday, clouds will eventually break for some sun by the mid
to late morning hours. A stray shower or sprinkle is still
possible for some high terrain or eastern areas, but most spots
should be dry on Monday. Temps will be mild once again,
especially once the sun returns by Monday afternoon, when temps
should reach back into the 70s for valley areas. Quiet weather
will continue into Monday night, with skies becoming mainly
clear and lows falling into the 40s.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
The long term period will begin will high pressure and upper
level ridging close to the area on Tuesday. This should allow
for a nice day with plenty of sun and rather mild temps. Many
valley areas may reach into the mid to upper 70s on Tuesday
afternoon.
However, the quiet and pleasant weather will only be short lived,
as the ridge will be breaking down for the middle to latter
portion of the week. The first in a series of shortwaves will be
moving across the area on Wednesday. Guidance suggest a wave of
low pressure will be tracking over or just north of the area.
As a result, a period of showers is expected for Wednesday and
some thunder will be possible as well (especially southern
areas). It should still be fairly mild with temps in the 60s and
70s once again.
Behind this initial disturbance, additional storms are expected
to impact the region, as an upper level trough sets up over the
Northeast and disturbances rotate across the region. With more
wet weather expected for Thursday through the weekend, will
continue to go with chc to likely POPs each day. A few
additional rumbles of thunder are possible from time to time as
well, although it will depend on just how much instability is
available. Temps still look close to normal, with highs in the
60s and overnight lows in the 40s to near 50 through the late
week and no threat for any frost/freeze in areas where the
growing season has begun.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Through 00Z Monday...VFR conditions expected to initially prevail at
all terminals, before vsbys/cigs trend downward to MVFR and possibly
IFR late tonight into early Sunday morning as showers arrive.
Current cigs at 4-6 kft will slowly lower while coverage increases,
reaching MVFR levels and becoming ovc by around 10Z at ALB/GFL/POU
and possibly a few hours earlier, before 06Z, at PSF. Shower
coverage increases from southwest to northeast, with MVFR vsbys
during rain showers after 10Z Sun along the Hudson Valley, and by 12-
14Z farther east at PSF. Cigs may continue to trend downward,
possibly reaching IFR levels after 15Z Sun. MVFR/IFR conditions
within rain showers will then continue through the remainder of the
period to 00Z Mon.
Southeast winds around 10-15 kt are expected throughout the period
at all terminals. Occasional gusts of 15-20 kt are additionally
possible at ALB/PSF. Late in the period, after 15Z Sun, winds will
begin to shift slightly out of the south to southeast. Low-level
wind shear may approach 30 kt out out of the south-southwest across
the region after 12-15Z Sun, but is at this point expected to remain
below thresholds.
Outlook...
Sunday Night: High Operational Impact. Breezy. Likely SHRA.
Monday: No Operational Impact. NO SIG WX.
Monday Night: No Operational Impact. NO SIG WX.
Tuesday: No Operational Impact. NO SIG WX.
Tuesday Night: Moderate Operational Impact. Chance of SHRA.
Wednesday: High Operational Impact. Likely SHRA...TSRA.
Wednesday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Thursday: High Operational Impact. Likely SHRA.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...Frugis
NEAR TERM...Frugis/Picard
SHORT TERM...Frugis
LONG TERM...Frugis
AVIATION...Picard
Area Forecast Discussion
National Weather Service La Crosse WI
1046 PM CDT Sat May 4 2024
.KEY MESSAGES...
- Fog possible tonight along and east of the Mississippi River.
- An active stretch of weather from Monday night through at
least Thursday as multiple rounds of showers move through.
Severe weather risk for Tuesday is trending south.
&&
.DISCUSSION...
Issued at 200 PM CDT Sat May 4 2024
TONIGHT: fog, frost?
With a day of wetting rains saturating the boundary layer and clouds
not slated to clear until near or after sundown, decent setup for
fog. Add in diminishing winds and the potential increases. Short
term models aren`t overly enthusiastic on the widespread possiblity
for thick/dense fog though. HREF and RAP hold any "thicker" type fog
to the I-94 corridor northward. Can`t rule out a thin fog layer in
the river layers too, ala what occurred a couple days ago. Will hold
with some mention of fog mostly along, east of the Mississippi river
for now.
In addition, passage of a cold front will bring in colder air with
lows expected to bottom out in the upper 30s to lower 40s. Some
potential for frost in low lying areas as a result, mostly in
central and north-central WI. Not widespread enough, nor high enough
confidence, to warrant a frost adv at this time.
Active Weather Pattern Next Week:
Shortwave ridging will be over the area through Monday. Warm
southerly flow and increasing PWATs are expected out ahead of a low
moving through the Upper Plains. Temperatures in the low 70s
expected. An 850mb jet with winds between 30 and 45 kts will be over
our area during the late evening on Monday and overnight period into
Tuesday. Convection across the Plains is expected to begin Monday
afternoon and push eastward throughout the day. Moisture
transport increases late in the day on Monday across eastern
Minnesota and Iowa. As the storms push eastward into Wisconsin,
even though shear and life potential increases, instability will
decrease. Thus the severe threat with this first round of
storms is low. Another factor that plays into the severe threat
is timing. These storms will push through the overnight period,
so daytime heating and the gradually weakening warm sector will
help to minimize the severe threat.
After this first round moves out by early Tuesdsay afternoon, model
guidance continues to show another round of storms forming over Iowa
as a shortwave pushes around the main low. While this wave does look
stronger with higher CAPE and lift potential, moisture advection is
weaker and so is the low-level shear. Even though the ingredients
are there to at least have some thunderstorm development, the
biggest inhibitors for development is that environment will
probably be worked over the morning thunderstorms and that the
warm sector will be further southeast of our area. At the
moment, southeastern Iowa and northern Illinois will have the
better chances at afternoon thunderstorm development.
From Wednesday through the rest of the week, this shortwave becomes
a cutoff low and the original low weakens and gets absorbed by the
new low. This cutoff low will be over the Upper Midwest providing
the area with northwest flow and periodic chances for precipitation
to occur. With this flow pattern, temperatures will cool down and
remain in the low to mid 60s from Thursday through the weekend.
&&
.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1045 PM CDT Sat May 4 2024
Main aviation forecast question for this TAF period revolves
around fog potential towards daybreak at LSE. Rainfall earlier
today combined with clear skies and light winds will prove
favorable, but the highest likelihood for fog development looks
to be along and north of I-94 in Wisconsin. Models have
struggled with recent post-rain fog events and are not very
supportive for fog at LSE late tonight, but observed dewpoint
depressions are dropping at this hour, so trends suggest the
possibility exists. Will introduce MVFR visibility (20%
probability) in the 06Z TAF, but confidence is only medium in
overall fog potential and how low visibility might drop. Right
now there is a small (10-15%) chance for IFR visibility at LSE
by daybreak and possibly some accompanying low stratus if this
full-on fog development scenario would pan out.
Otherwise VFR conditions for the TAF sites with light winds
under 10 knots, fluctuating between westerly and southerly as
high pressure drifts overhead.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...Cecava/Rieck
AVIATION...Kurz
Area Forecast Discussion
National Weather Service Goodland KS
1003 PM MDT Sat May 4 2024
.KEY MESSAGES...
- Monday will see a chance for severe thunderstorms east of
Highway 25 in northwest Kansas and southwest Nebraska from the
late morning to mid afternoon hours.
- Also on Monday, for areas west of Highway 25 near critical to
critical fire weather conditions will be likely during the
afternoon due to low humidity and gusty west winds. Some
patchy blowing dust will also be possible.
&&
.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 130 PM MDT Sat May 4 2024
High pressure in control today with light winds and mostly sunny
skies. Tonight, return flow around the high begins with
increasing southeasterly winds. Stratus will develop by 12z in
the Kansas and Colorado border area, with perhaps some patchy
fog, expanding across much of the area through the morning. HRRR
suggests the low clouds will be slow to erode through Sunday
afternoon in central and eastern portions of the area,
potentially impacting temperatures. Hard to find much support
for lower temperatures in guidance, so will only tweak
temperatures down a few degrees in eastern areas. It will also
be windy with south to southeast winds gusting over 40 mph in
western areas by the afternoon as a trough deepens in eastern
Colorado. Lows tonight will be in the lower 40s and highs on
Sunday in the 60s in the aforementioned cooler areas to the
lower 70s in western areas with some afternoon sun.
Sunday night will see those winds continue to increase. Models
may be over mixing, particularly the GFS, but still going to be
breezy to windy south winds through the night. Upper trough axis
will be in central Colorado by early Monday morning. May see
scattered showers begin to develop overnight Sunday with an
isolated thunderstorm or two with favorable MUCAPE.
As upper trough lifts into the Nebraska panhandle Monday morning
westerly winds will overspread the area aloft and at the
surface. Dry line will race eastward in the morning and by 18z
probably be all the way to Highway 83. There is a short window,
between about 16z and 20z, when the dry line may still be in
the area and thunderstorms may initiate. Forecast soundings
from the NAMnest, which initiates storms on the dry line in the
eastern six counties, shows around 1500 j/kg of SBCAPE and 60
kts of 0-6km shear, which should be sufficient for a severe risk
of large hail, damaging winds and perhaps a tornado. Meanwhile,
west of the dry line it will be dry and windy with a risk for
critical fire weather conditions. Lowest humidity will be south
of Interstate 70 and west of Highway 25 with high probabilities
for relative humidity of 15% or lower and for wind gusts of 25
mph or higher. However, models not in the best of agreement on
potential for meeting high wind warning criteria. NBM
probabilities for gusts of 55 mph or greater are generally
confined to Colorado during the morning at 20-30 percent,
decreasing in the afternoon. Finally, low level lapse rates west
of the dry line are favorable for blowing dust, but wind gusts
a bit lacking, and recent rainfall may negate some of the
potential as well. Precipitation should be done for the area by
Monday afternoon. Highs will be in the lower 70s and lows Monday
night ranging from the upper 30s in Colorado to the lower 40s
in eastern areas.
On Tuesday, the upper low will be in the northern plains with
zonal flow across the central plains. It will be breezy to
windy and dry. Critical fire weather conditions may be met once
again, but potentially more widespread compared to Monday with
just about the entire area dropping into the teens for humidity
in the afternoon. High temperatures will be in the 70s and lows
Tuesday night ranging from the middle 30s in Colorado to the
lower 40s in eastern areas.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Issued at 130 PM MDT Sat May 4 2024
Upper low in the northern plains will be the dominant feature
Wednesday through Friday. Occasional shortwave energy rotating
around it will bring low chances for showers and thunderstorms.
However, moisture will be lacking, dew points in the 20s on
Wednesday and 30s on Thursday and Friday, so no severe storms
are anticipated. With those low dew points on Wednesday and
continued gusty west to northwest winds may see another day of
critical fire weather across parts of the area. Highs will be
mainly in the 60s and lows in the 30s and 40s each day.
By Saturday appears the upper low will finally lose its
influence over the area with shortwave ridging ahead of the next
system in the Great Basin. Temperatures will warm up slightly
with highs in the 60s and 70s with only low chances for an
afternoon shower or thunderstorm with a weak wave coming over
the ridge.
&&
.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1002 PM MDT Sat May 4 2024
For KGLD, conditions start as VFR through about 08z Sunday,
then transition to MVFR with 5-6sm in fog and ceilings around
BKN015-025. VFR do not return until 03z Monday onward. Winds,
southeast 10-15kts, increasing to around 25-35kts from 17z
Sunday onward.
For KMCK, VFR conditions through much of the forecast period,
with MVFR ceilings(BKN015-020) working into the area by 00z
Monday. Winds, southeast 10-15kts through 17z Sunday, then
increasing to around 20-30kts. LLWS 00z-06z Monday 160@45kts.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...None.
CO...None.
NE...None.
&&
$$
SHORT TERM...24
LONG TERM...24
AVIATION...JN
Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
1028 PM CDT Sat May 4 2024
.KEY MESSAGES...
- Scattered thunderstorms will develop this afternoon west of
Interstate 57, mainly between 3pm and 9pm. The potential severe
weather hazards include hail to the size of ping pong balls and
damaging wind gusts up to 60 mph.
- Confidence is medium that hazardous weather will occur both
Tuesday and Wednesday as a pair of disturbances track across the
region, bringing periods of thunderstorms.
&&
.UPDATE...
Issued at 807 PM CDT Sat May 4 2024
A cold front is working across central Illinois this evening with
a line of showers and thunderstorms preceding the front. In
addition, a gust front has surged ahead of the leading edge of
storms and is kicking up some dust resulting in lowered visibility
in some areas. Overall, the severe threat has diminished from
earlier and will continue to trend down, but will need to continue
to monitor for a stronger storm or two over the next couple
hours. Gusts of 40 to 50 mph will be possible in spots with the
strongest storms. Leading edge of the storms should clear the
forecast area by around 1000/1030 pm with precip chances ending
altogether in the following hour or two. Behind the front, breezy
northwest winds are overspreading the Illinois River Valley with
upstream dewpoints in the 40s expected to work across at least the
Illinois River Valley through the night.
Deubelbeiss
&&
.DISCUSSION...
Issued at 141 PM CDT Sat May 4 2024
*********************************************************************
Today`s Severe Weather Potential:
*********************************************************************
Up until this point, two limiting factors for afternoon convective
coverage has been the idea that deep-layer shear is somewhat
underwhelming (30 kts or less), and that synoptic forcing atop the
cold front is somewhat nebulous. If true, then updrafts may
struggle to get organized or struggle to stay organized -- thus
limiting the severe risk.
However, we have recalibrate our expectations due to a decaying
MCV currently lifting across northeast Missouri. MCVs notoriously
augment forcing and vertical wind profiles, and it bears watching
over the next couple hours. If this feature can hold together as
it crosses the mid-Mississippi Valley, then convective coverage
should become greater than previously anticipated.
A quick glance at the RAP-derived parameter space suggests the
mesoscale environment this afternoon will be sufficiently unstable
as steepening 0-3 km lapse rates and good solar insolation work to
erode convection inhibition. SBCAPE values are now progged to be
2000-2500 J/kg ahead of the cold front; which is a notable increase
from yesterday`s modeled instability.
This all adds up to increased confidence in severe weather coverage
this afternoon and early evening in areas west of I-55.
The primary severe weather hazards are still hail and wind, and
recent HRRR guidance suggests that the latter could be the more
formidable feature as cold pools strengthen ahead of the front.
Any attendant flash flood risk with storm activity looks low. The 3-
hr flash flood guidance in areas west of I-55 is currently between
1.5" - 2.0". When overlaying the HREF 3-hr PMM QPF, this same area
only achieves 0.5" - 1.0". It`s at least worth noting that recent
runs of the HRRR offer a couple localized QPF pockets of 1.75", but
any flash flooding that occurs would be the exception and not the
rule.
Our expectation is still for severe convection to fade after sunset,
as the lack of an appreciable LLJ will make it difficult for storms
to maintain their punch.
*********************************************************************
Tuesday-Wednesday Severe Weather Potential:
*********************************************************************
A seasonable and otherwise low-drama forecast has been drawn up for
Sunday and Monday, but concern quickly focuses on the convective
potential unfolding during the Tuesday-Wednesday timeframe. Global
deterministic guidance continues to resolve a synoptic pattern
favorable for a multi-day severe weather outbreak, and this signal
is reflected in other analogs (CIPS) and machine learning tools (CSU
MLP Severe).
In a sentence or two, we`re monitoring the evolution of what looks
to be a deepening upper-level low positioned over the Northern
Plains by Monday night, with a strong jetcore nosing into the Mid-
Mississippi Valley above multiple shortwaves traversing meridional
flow. This combination of strong forcing, strong kinematics, and
favorable thermodynamics evolving in deep southwest flow could lead
to widespread severe weather within a broadening warm sector.
Our confidence at this time is only medium, as we cannot possibly
imagine how certain mesoscale processes (convective feedback,
debris, outflow boundaries, etc) evolve in time and space. But,
the synoptic setup currently being modeled for Tuesday-Wednesday
is concerning.
When leveraging our 100-member ensemble comprised of the GEFS, EPS,
and CMCE to assess a favorable parameter space for supercell
development (SBCAPE > 1000 J/kg, SBCINH > -75 J/kg, and bulk shear >
40 kts), we see a 50-70% chance of achieving these conditions on
Tuesday in areas along and south of I-72. When looking toward
Wednesday, we see probabilities of 50-60% in areas south of I-72.
And so while the emphasis appears to currently favor the southern
half of our CWA on both days, our confidence is only medium. The
severe weather outlook will undoubtedly change in coming days, so do
check back.
MJA
&&
.AVIATION... (For the 06z TAFs through 06z Sunday Night)
Issued at 1028 PM CDT Sat May 4 2024
A cold front has pushed across central Illinois leaving NW winds
in its wake. NW winds in place overnight will veer to the NE
Sunday morning and east Sunday evening. MVFR ceilings are expected
to develop across portions of the area, mainly along and east of
I-55 overnight into Sunday morning, but any ceilings should
scatter back to VFR by around midday Sunday.
Deubelbeiss
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Jackson MS
1033 PM CDT Sat May 4 2024
...New MESOSCALE UPDATE...
.MESOSCALE UPDATE...
Issued at 1030 PM CDT Sat May 4 2024
Rest of tonight...
Evening RAP analysis/GOES East water vapor imagery westerly flow
aloft across the region, with dwindling rain chances. Stronger
shortwave ascent is again leading to ascent & GOES East infrared
imagery indicate MCS/cold cloud tops across the southern Plains.
PWs have come up across the region but most convection has died
down. Clouds will gradually fill in from the west, with rain after
daybreak, but moist southeasterly boundary layer flow will pick up
before then. Lows will fall into the mid-upper 60s, with
crossover temps not as as much as last night & focused more into
southern-southeast MS. This pattern supports low stratus & dense
fog developing overnight across the Hwy 84 to I-59 corridors. HREF
probs >15-30% expanding up to near the I-20 corridor, but some
concerns with clouds lingering & high clouds later decrease some
confidence. Convective allowing models (CAMs) indicate potential
for areas of dense fog across the Pine Belt, mainly focused along
& southeast of a line from Lincoln, Lawrence, Simpson, Smith,
Jasper & Clarke counties in MS. Added a "Limited" in HWO graphics
for patchy dense fog. Can`t rule out it expanding further north &
being more areal coverage. Some HREF probs are hitting pretty
hard in the 35-50% range in the Jefferson Davis to Jones & Marion
to Forrest corridor. Held off on any "Elevated" or dense fog
advisory for now. Updates are out. /DC/
&&
.DISCUSSION...
Issued at 253 PM CDT Sat May 4 2024
Tonight through Sunday...Isolated showers/storms will be possible
into the early evening hours, but will dissipate with skies
becoming partly cloudy overnight. A short wave will move into the
area on Sunday with more scattered showers/storms Sunday afternoon
and evening. With decent instability, afternoon heating and at least
some flow, strong to possibly severe storms will be possible mainly
for areas along and north of the Natchez Trace Corridor. A graphic
has already been issued for this potential. Highs will range from
around 80 in the west to the upper 80s in the east. The storms will
move east of the area during the evening hours. /15/
Monday through Saturday:
As a closed low pressure system cuts off over the Northern High
Plains through the early part of the work week, upper-level flow
over the Southern CONUS will increase. Ripples in the flow
interacting with a warm, moist air mass over the Gulf Coast will
continue to support mainly diurnal showers and thunderstorms through
midweek. Thursday into Friday, ridging over the eastern CONUS is
expected to flatten and allow for shortwave energy to eject east
across the Midwest and Great Lakes region. A cold front pushing
south into our forecast area during this time frame will be a focus
for additional shower and thunderstorm activity, eventually yielding
to cooler and drier air with high pressure coming out of the Plains.
/NF/
&&
.AVIATION...
(00Z TAFS)
Issued at 753 PM CDT Sat May 4 2024
Other than a few storms on the edges of the area in the northwest
MS and southern MS, expect dissipation over the next hour or so.
Some MVFR vsby due to BR are psbl around the area, with LIFR low
stratus/dense fog expected overnight at HBG/PIB & psbl at MEI.
Onset timing looks to be around 05/08-10Z before lifting to VFR
flight categories around 05/14-15Z. Light southerly sfc winds
will persist, sustained up to 10mph & brief higher gusts up to
15mph. Some light SHRA & iso TSRA are psbl Sunday aftn, with
highest confidence for introduction at GLH & GWO for the 00Z TAF
cycle. There are low probs at GTR, JAN, HKS & HEZ after 05/20-21Z
through the end of the period. /DC/
&&
.PRELIMINARY POINT TEMPS/POPS...
Jackson 65 84 67 86 / 20 50 30 30
Meridian 64 88 65 88 / 20 50 30 30
Vicksburg 66 83 66 86 / 10 50 30 30
Hattiesburg 66 88 68 88 / 20 30 10 20
Natchez 66 83 66 86 / 20 50 20 30
Greenville 67 80 68 84 / 10 60 60 30
Greenwood 66 83 67 85 / 10 70 60 40
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...None.
LA...None.
AR...None.
&&
$$
DC/NF/DC
Area Forecast Discussion
National Weather Service Lake Charles LA
1007 PM CDT Sat May 4 2024
...New UPDATE...
.UPDATE...
Issued at 1002 PM CDT Sat May 4 2024
Area radar shows a couple of thunderstorms moving into
Hardin and Jefferson county at this time, with more activity back
to our west. Short term models are still in good agreement with
shower and thunderstorm activity increasing further after midnight
(mainly for SE TX), followed by another MCS feature moving across
the region tomorrow around sunrise. Therefore, only made some
small changes to the hourly POP forecast over the remainder of the
overnight period, just to fall more in line with current radar
and CAMs trends. Otherwise, the forecast is on track.
17
&&
.SYNOPSIS...
Issued at 356 PM CDT Sat May 4 2024
Scattered convection continues to develop across the area this
afternoon in response to a subtle disturbance passing over the
region. This activity continues to develop in a very moist
airmass, with PWATs around 1.70 inches (around the 90th
percentile per SPC Climo). Given the considerable moisture, some
storms could be capable of producing heavy rainfall and very high
rain rates, potentially aggravating ongoing flooding across SE TX.
So far today, a few small cells have produced heavy rains,
yielding increased flows per FLASH data, but convection has not
been particularly robust and the generally progressive nature
has helped limit flash flooding.
Otherwise, the rainy pattern is expected to persist with another
disturbance moving into the region tonight into Sunday. A Flood
Watch has been issued for our SE TX Counties, as any additional
rain over the saturated ground will contribute further to ongoing
flooding.
24
&&
.SHORT TERM...
(Tonight through Monday night)
Issued at 356 PM CDT Sat May 4 2024
This afternoon`s convection is expected to diminish by early this
evening. The next round of showers and storms will be forming
across TX and moving into the area later tonight after midnight.
Rain chances will expand and increase from west to east overnight
into Sunday.
PWATs are progged to remain elevated across the region (peaking
between 1.6 and 1.7 inches, or slighter higher). Sufficient lift,
instability and deep layer shear will support organization and
strong updrafts to allow for both heavy rainfall and a low end
severe threat. A few isolated storms could produce a damaging wind
gust or two as well as some marginally severe hail, although
convection will likely weaken as it progresses east. SPC has
outlined a MRGL risk for severe weather given this scenario.
The more impactful threat however continues to be the potential
for heavy rainfall over an area that is already saturated, with
moderate to major river flooding ongoing. WPC has outlined
much of our SE TX areas with a MDT risk for excessive rainfall
tonight into Sunday. The HRRR, ARW and HREF show some of the
highest rainfall accumulations across Tyler, Hardin and Jefferson
Counties (areas that have already received between 8 and 12 inches
of rain over the past week). At this time, blended guidance and
WPC suggest area totals of 1 to 3 inches of rain across this area,
but localized higher totals of up to 6 inches will certainly be
possible (possibly higher if some guidance members verify).
There is still some uncertainty when the rain chances will finally
begin to decrease as the HRRR and ARW suggest one last cluster of
convection will move through early Sunday evening. Rain chances
should begin to diminish after midnight Sunday night, but some low
chances will develop again with daytime heating on Monday.
24
&&
.LONG TERM...
(Tuesday through next Friday)
Issued at 356 PM CDT Sat May 4 2024
At the start of the extended period low pressure will be across the
northern plains with weak ridging across the northern gulf coast
into the Atlantic. This is anticipated to produce dry but breezy
conditions across the local area for Tuesday and Wednesday.
Temperatures are also expected to run several degrees above climo
normals for the date.
Late in the week, an upper trough and associated surface low will
move across the upper midwest and Great Lakes region. This may push
a cold front to the gulf coast by Friday, however ahead of the
boundary, compressional heating may nudge high temperatures in the
90s north of I-10 Thursday afternoon. Showers and storms may be
possible along the boundary, but overall coverage is only forecast
to be in the 10 to 30% range at the current time. Drier and cooler
temperatures are forecast to filter in behind the boundary for the
weekend.
05
&&
.AVIATION...
(00Z TAFS)
Issued at 638 PM CDT Sat May 4 2024
Generally VFR will transition to MVFR/IFR later this evening with
increasing risk for Iso/Sct convection. Probabilities further
increase after midnight and early morning hours, especially for
KBPT and eventually KLCH. Later in the morning and early afternoon
probabilities will rise for locales east of KLCH.
Better timing and impacts for TAF locales will be issued later
this evenign with updated high reoslution modeling.
&&
.MARINE...
Issued at 356 PM CDT Sat May 4 2024
A light to moderate onshore flow and seas two to four feet will
prevail for much of the upcoming week. Scattered showers and
storms are again expected to develop tonight into Sunday, then
diminishing Sunday night with rain chances remaining limited
through the week.
24
&&
.HYDROLOGY...
Issued at 356 PM CDT Sat May 4 2024
River flooding is expected to persist for several days, and
additional rainfall on Sunday may extend or worsen conditions
within area basins.
Moderate to Major Flooding continues within the Neches River
basin, with major flooding occurring or forecast on the Village
Creek near Kountze, the Pine Island Bayou at Sour Lake and at the
Neches River Saltwater Barrier. Moderate flooding is also expected
along the Sabine River from Bon Wier to Deweyville. Further east,
flooding remains in minor category along the Calcasieu River.
Please monitor updated forecasts via the NWS AHPS website
and/or the new NWS NWPS webpage (https://water.noaa.gov/) as the
river flood threat continues.
24
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 67 82 66 85 / 30 60 20 30
LCH 71 83 71 84 / 20 40 20 20
LFT 71 85 72 86 / 10 40 20 20
BPT 72 82 71 84 / 30 50 20 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...Flood Watch through Sunday evening for TXZ180-201-259>262-515-
516-615-616.
GM...None.
&&
$$
SHORT TERM...24
LONG TERM....05
AVIATION...24
Area Forecast Discussion
National Weather Service Louisville KY
1110 PM EDT Sat May 4 2024
.KEY MESSAGES...
* Isolated to scattered showers and thunderstorms are forecast
this afternoon. Slow moving storm motion and moderate to heavy
rain expected with any storm.
* Isolated showers and thunderstorms are expected on Sunday before
widespread rain chances return Sunday night into Monday.
* Potential for multiple rounds of strong to severe storms next
Tuesday through Thursday. Although confidence in timing remains
low, all severe hazards will be possible.
* Elevated flooding potential will exist where repeated rounds of
heavy rainfall occur next week.
&&
.UPDATE...
Issued at 1109 PM EDT Sat May 4 2024
Over the past 90 minutes or so, there has been an uptick in
thunderstorm activity across our westernmost counties, where latest
SPC mesoanalysis delineates 500-1000 J/kg MLCAPE. It is also
noteworthy that there are where the greatest amount of convection is
currently ongoing has largely been rain-free this afternoon, and a
relative minimum in CIN is observed in these areas. Finally, outflow
from storms along the frontal boundary farther west has likely
spurred this development to some extent, providing just enough
mechanical lifting to raise initially stable parcels to their LFC.
Over the next few hours, would expect convective activity to spread
eastward across southern IN and west central KY, gradually
diminishing after midnight as instability continues to wane.
The only notable changes to the going forecast were tweaks to PoP
grids over the next 3-6 hours. Otherwise, the forecast remains on
track at this time.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 348 PM EDT Sat May 4 2024
========== Rest of This Afternoon ==========
Fairly moist atmosphere over the area, with precipitable waters
around the 90th percentile. Storms have developed in this humid
airmass, with best convective development where the MLCAPE per SPC
mesoanalysis is over 1000 J/kg. Louisville ACARS most recent
sounding shows a couple of small inversions, at ~800 mb and 700 mb,
which may be inhibiting deeper development over the city. HRRR
sounding forecast represents these inversions well and keep them in
place through the afternoon. Thus will keep the best chances for
storms east of the i-65 corridor.
========== Tonight ==========
Showers/Storms from the afternoon should steadily decrease this
evening. Cannot rule out some isolated development in the moist
airmass. Should be another mild night as dewpoints remain elevated
and lows by Sunday morning should be in the low 60s. Model progs
keep clouds around overnight and thicken/lower them during the
morning hours.
========== Sunday ===========
How long those low clouds hang around in the morning and early
afternoon hours will have a direct influence on afternoon
convection. Have bumped PoPs down a touch, with the better chances
south and east of a Russellville to Bardstown to Frankfort line.
Some CAM`s have gone dry for the afternoon, but given potential for
some breaks in clouds and precipitable waters still above normal,
though not as much, feel prudent to keep in some storm chances.
Temperatures should rise into the 80`s for most places.
&&
.LONG TERM /SUNDAY THROUGH SATURDAY/...
Issued at 348 PM EDT Sat May 4 2024
Synopsis...A multi-day severe weather episode will be possible by
the middle of the next week as an upper-level trough evolves and
amplifies over the central US and eastern CONUS upper ridge axis
transitions from the Great Lakes to the Mid Atlantic/Southeast US.
The timing for best chances of severe weather will be tied to the
progression of periodic, mid-level shortwave troughs rounding the
base of the large through and embedded upper low. Eventually,
continuous ejection of strong shortwave troughs will carry the main
upper low energy towards the eastern CONUS while deeply amplifying
once again due to further reinforcement from upstream Canadian
troughing.
Model Evaluation/Confidence...Confidence in large-scale features
continue to be medium to high with expected decreasing confidence in
timing and intensity of shortwaves ejecting ahead of the main upper
low. The timing differences in incoming strong mid-level forcing
could lead to great variability in convective intensity, coverage,
and maintenance based on a potential onset time around sunset (both
Tuesday and Wednesday) and the resultant distribution/amount of
available daytime instability. Also, it is too early to pinpoint
specifics about meso features that would certainly play an important
role in initiation convection, such as the position of the residual
outflow boundary on Tuesday afternoon/evening or the effect of
previous convection and the interaction with approaching frontal
wave on Wednesday. In any case, machine learning derived guidance
has been consistently highlighting elevated probabilities of severe
weather across the region for Tuesday and Wednesday, with a recent
trend for higher probabilities for Wednesday.
Sun Night - Monday...Increased shower activity along with some
isolated storms are likely Sun night into Monday morning as a
southern-stream shortwave trough moves from the southern Plains to
the lower Ohio Valley. A combination of increased moisture advection
and potentially slow storm motions/backbuilding could result in
isolated accumulations over half an inch or more. On the other hand,
warming mid-level temperatures and decreasing instability will limit
thunder chances and promote more of a low-centroid type of storms.
The vorticity wave will push a frontal wave stalled across the
region to the north, so will keep mentioning reduced PoPs during the
afternoon and evening.
Tuesday - Thursday...Daily severe weather chances appear to focus
around sunset and overnight every day. For Tuesday, a weakening cold
front will move into the forecast area Tuesday morning and early
afternoon and although there will be an increase in showers during
the morning, it seems that forcing will subside substantially to
reinvigorate convection. Nonetheless, the residual outflow boundary
will establish somewhere along the Wabash Valley and into central
Indiana, which could be the mesoscale focus for convection late in
the afternoon and early evening as a surface low (ejecting across
the Upper Midwest) drags a cold front to the southeast. Based on
current guidance, highest severe probs will be close to the outflow
boundary further north with a decreasing trend in convective
intensity as it approaches southern Indiana and north-central
Kentucky. On the other hand, Wednesday looks more threatening as the
front will be located closer to the forecast area and the second mid-
level shortwave energy brings a surface low across the Wabash Valley
and IN. Therefore, forcing will be significantly higher amid a
moderately high unstable warm sector and sufficient deep-layer shear
for organized, spinning updrafts. All severe hazards are on the
table as well as a risk of flooding given the possibility of
repeated rounds of heavy rainfall.
Friday - Sunday...Amplifying trough over the eastern CONUS will push
the cold frontal and associated unsettled weather activity south of
the forecast area. As a result, rain and storm chances will decrease
during the day on Friday with breezy NW winds and persistent low-
level cloud cover the rest of the day. Temperatures during the
weekend seems to fall near or slightly below normal under light NW
breeze and partly to mostly skies. A more stable airmass will
indicate dry conditions for Saturday and Sunday.
&&
.AVIATION /00Z TAFS THROUGH 06Z MONDAY/...
Issued at 802 PM EDT Sat May 4 2024
We currently have a line of thunderstorms in central
Illinois. The line is oriented north to south and will continue
traveling to the east. The line is expected to impact the area of
HNB and could make it to SDF later tonight. Ceilings around
convection have been bouncy, but later tonight/ early tomorrow
morning, expecting MVFR to IFR stratus to develop over southern
Indiana and central Kentucky. Ceilings during this time could also
see some jumping around between VFR and IFR levels. Winds will
remain light and slowly begin veering towards the west tomorrow.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...None.
IN...None.
&&
$$
UPDATE...CSG
SHORT TERM...RJS
LONG TERM...ALL
AVIATION...KDW
Area Forecast Discussion
National Weather Service Memphis TN
945 PM CDT Sat May 4 2024
...New UPDATE...
.UPDATE...
Issued at 929 PM CDT Sat May 4 2024
Fairly quiet this evening as mid level shortwave ridging spreads
into the region ahead of the next disturbance moving toward the
Arklatex. Fog is the main concern once again this evening. Best
chances appear to be across the TN River Valley and NE MS where
dewpoint depressions are already 1 degree or less. Confidence is
not quite as high as last evening since the HRRR has not really
jumped on board yet. Ongoing forecast handles it well and we will
monitor fog development for potential Dense Fog Advisory later
tonight. The next disturbance will swing through on Sunday
afternoon with numerous showers and thunderstorms. A few severe
storms are possible with gusty winds and large hail.
&&
.SYNOPSIS...
Issued at 326 PM CDT Sat May 4 2024
Warm and humid conditions will support scattered to numerous
showers and thunderstorms through the middle of next week. A few
severe thunderstorms will possible on Sunday, as an upper level
disturbance lifts from Texas into the lower Mississippi River
Valley. Severe thunderstorm chances will increase by midweek,
ahead of a deep upper level low pressure system moving through the
Great Plains and mid-Mississippi River Valley.
A cold frontal passage on will bring cooler and less humid conditions
to the Midsouth by next weekend.
&&
.DISCUSSION...
(This evening through next Friday)
Issued at 326 PM CDT Sat May 4 2024
An active weather pattern is ahead for the Midsouth through the
middle of next week.
A convectively- enhanced shortwave will lift from west central
Texas into the western Ozarks by midday Sunday. Mixed layer CAPE
over the Midsouth will increase to 1000-1500 J/kg. 0-6km bulk
shear will prevail at 20-30kt, relatively modest but about double
that of today. This will support a marginal severe threat by
midmorning Sunday. Damaging winds, hail and heavy rainfall appear
to be the primary threats. Given the projected timing of the
shortwave, storms should exit and/or diminish by Sunday evening.
Monday should be relatively quiet under shortwave ridging. But the
ridge axis will be east of the area Monday evening, opening the
door for storms to enter the Midsouth from southern AR, aided by a
40kt low level jet.
Severe thunderstorms are appearing more likely Tuesday and
Wednesday, aided by height falls associated with a deepening northern
branch longwave trough over the western two-thirds of the CONUS.
Low level return flow will strengthen in response, driving surface
dewpoints to around 70F over the Midsouth. The increased low
level moisture will drive surface-based CAPE in excess of 2500
J/kg Tuesday afternoon, accompanied by 0-6km bulk shear around
45kt north of I-40.
With strong southerly flow continuing, the lower atmosphere should
recover Wednesday from Tuesday night storms. An upper level
trough axis, pendant from a closed low over eastern Nebraska, will
pivot through the Ozarks Wednesday afternoon and evening, driving
height falls and enhancing frontal convergence over the lower
Ohio River Valley and Midsouth. Surface-based CAPE will peak
around 3000 J/kg Wednesday afternoon, before moderating below a
still impressive 1500-2000 J/kg Wednesday evening. GFS and ECMWF
mean 700-500mb lapse rates are progged at an impressive 8 C/km
Wednesday afternoon and evening. Given the projected CAPE, this
would be supportive of very large hail, at least during the
afternoon. Given the tendency for prefrontal veering of low level
winds, convection may transition to a linear mode Wednesday
evening, perhaps reducing the large hail and tornado threat, but
enhancing the flash flooding threat. Projected PWAT is around 2
inches, about as high as it gets this time of the year.
Quieter weather should prevail Thursday, following the passage of
the convectively-reinforced cold front. Another cold frontal
passage appears likely on Friday, as a deep longwave trough
sets up briefly over the eastern CONUS. This should bring relatively
cool and dry conditions to the Midsouth next weekend.
PWB
&&
.AVIATION...
(00Z TAFS)
Issued at 710 PM CDT Sat May 4 2024
Near term aviation concerns pertain to the development of reduced
visibilities, ceilings, and possible fog overnight as winds go
calm and variable. High resolution CAM guidance depicts a line of
showers and thunderstorms that will move through the airspace
sometime tomorrow afternoon. Have elected to use a PROB30 for now
with respect to this situation until further details can be
resolved.
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
PUBLIC FORECAST...SJM
AVIATION...JPR
Area Forecast Discussion
National Weather Service Shreveport LA
1044 PM CDT Sat May 4 2024
...New UPDATE...
.UPDATE...
Issued at 1033 PM CDT Sat May 4 2024
Not much change from previous forecast for this evening into the
overnight hours. A large complex of showers and thunderstorms have
formed across portions of West and North-Central Texas. The HRRR,
which seems to have a good handle on this set-up, continues to
suggest this complex will form into a MCS and shift eastward
towards the region during the overnight hours. Can`t rule out an
isolated strong to severe thunderstorm, with damaging winds and
large hail being the primary threat. Moderate to heavy rainfall
can also be expected. Although WPC has a Moderate Risk for
excessive rainfall across portions of Deep East Texas and a Slight
Risk for a large portion of the region, decided to hold off on a
Flash Flood watch at this time. RFC Flash Flood Guidance suggest
we can handle the expected amount of QPF, but this will need to
be monitored closely. Otherwise, expect overnight lows in the mid
to upper 60s. /20/
&&
.SHORT TERM...
(This evening through Sunday Night)
Issued at 310 PM CDT Sat May 4 2024
A few showers and thunderstorms will persist through early this
evening, mainly across portions of Angelina, San Augustine, and
Sabine Counties along a stalled surface boundary. Most of the
heavier storms should remain south of the CWA. Farther north, more
isolated convection associated with a shortwave trough approaching
the Mississippi River should exit the area by early this evening.
In fact, most of the ongoing precip should end by sunset. However,
this break will only be temporary.
Another complex of strong to severe thunderstorms is expected to
develop across West Texas this evening and tonight as the next
shortwave trough strengthens while ejecting northeast across Texas
and towards the ArkLaTex. The HRRR and HREF have tended to perform
the best over the last couple of days, so this forecast more
closely follows those models versus the NAM, GFS, and ECMWF. This
is also results and earlier time of arrival of the leading edge
of the storms into Southeast Oklahoma and East Texas, which should
be between 05z-09z (midnight-4 AM CDT)tonight/Sunday morning. This
complex should weaken somewhat with eastward extent across the
forecast area Sunday morning, but an isolated severe weather
threat cannot be ruled out. Damaging winds and large hail should
be the main threat.
The forecast becomes more uncertain after mid to late Sunday
morning. The HRRR suggests a notable lack of convection across
most of the CWA with the exception of the far northern and far
southern zones, probably because the atmosphere should be worked
over. However, there may be some recovery during the day, which
should allow for renewed, and likely more scattered development.
This is most likely across Southeast Oklahoma, Southwest Arkansas,
and Northeast Texas where lift will be maximized with the
shortwave trough. Farther south, a series of thunderstorms
complexes with the potential to produce locally heavy rain is
possible as a secondary wave in the flow aloft moves across
Southeast Texas. Current thinking is that most of this convection
should remain just south of the CWA. It is somewhat concerning,
and worth noting, that the NAM brings this heavy rain threat into
Deep East Texas Sunday afternoon, which would increase the risk
for flooding.
There is a moderate risk for excessive rainfall in portions of
Deep East Texas on Sunday per WPC. For our area, this appears to
be associated mainly with the morning convection. While locally
heavy rain is possible, the risk for flooding is expected to be
short-lived and localized at this time, especially as compared to
areas just south and southwest. Therefore, we opted to forego
issuing a Flood Watch. Overall, an additional 1 to 3 inches of
rainfall, with locally higher amounts, are possible through
Sunday evening in Deep East Texas.
Rain chances should finally diminish from southwest to northeast
Sunday night and early Monday morning.
CN
&&
.LONG TERM...
(Monday through next Friday)
Issued at 310 PM CDT Sat May 4 2024
Strong southwesterly flow aloft associated with a powerful upper
low across the Northern Plains combined with a deep low-level
southerly flow will keep a rather abundant pool of moisture
throughout the atmospheric column. With a cold front northwest of
the area, this will keep near daily chances for scattered
convection in the forecast for much of next week. Sufficient
instability and deep layer shear will also result in at least some
threat for severe storms each day. The highest rain chances and
corresponding chances for severe weather should be Wednesday and
possibly into Thursday as a cold front finally approaches and
moves across the area. The greatest coverage and best rain chances
can be expected in the afternoons and evenings.
Surface ridging should finally build into the area by Friday and
into Saturday providing enough subsidence and dry air advection to
bring most of our rain chances to an end. While the deterministic
GFS and ECMWF remove all chances for rain, the ensembles and the
NBM still keep some light QPF and slight chances for rain in the
forecast as one more shortwave trough dives south along the
Mississippi River to start the weekend.
With the strong southerly surface flow at the beginning of the
week, strong warm air advection can also be expected. With showers
and thunderstorms being more of a scattered nature, temperatures
will be able to climb ever upwards. Confidence continues to
increase regarding unseasonably high temperatures, especially next
Tuesday through Thursday. NBM probabilities of high temperatures
of at least 90 deg F are now on the order of 80 to 90 percent in
some portions of Louisiana by Wednesday. With peak heat index
values near the century mark, the hot and humid conditions will be
more typical of mid June versus early May.
CN
&&
.AVIATION...
(00Z TAFS)
Issued at 707 PM CDT Sat May 4 2024
Skies are anticipated to fall overnight, as clouds and rain move
back into the region by tomorrow morning. Widespread MVFR and IFR
CIGS should return by 05/10z, with RA and SHRA following shortly
after. There is a chance for some thunderstorms tomorrow
afternoon, but confidence was not high enough to introduce TS at
this time.
/44/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 69 79 68 85 / 70 100 30 40
MLU 69 80 66 86 / 20 60 40 40
DEQ 67 73 63 80 / 70 100 30 30
TXK 69 75 66 84 / 70 100 40 40
ELD 68 76 63 83 / 30 80 40 40
TYR 68 79 68 85 / 90 80 20 20
GGG 69 78 67 84 / 90 100 20 30
LFK 68 80 68 86 / 80 100 10 20
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
SHORT TERM...09
LONG TERM....09
AVIATION...44