Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/27/24
Area Forecast Discussion
National Weather Service La Crosse WI
1100 PM CDT Sat Oct 26 2024
.KEY MESSAGES...
- Seasonable conditions this weekend will give way to near-
record temperatures early next week. Tuesday will likely be
the warmest day with high temperatures reaching 80 degrees for
many.
- Precipitation chances increase throughout the first half of
next week with the highest chances (60-90%) being overnight
Tuesday and on Wednesday.
&&
.DISCUSSION...
Issued at 152 PM CDT Sat Oct 26 2024
Dry and Seasonable Conditions To End Weekend:
GOES-16 water vapor imagery and 26.15z RAP 500mb heights this
afternoon show our region subjected to northwesterly flow with upper-
level ridging situated to our west and broad troughing to the east.
As a result, with our local area situated at the inflection point of
the upper-level flow, surface high pressure is firmly in place
allowing for clear conditions with light winds. As we head through
the day tomorrow, the high pressure center will push southeastward
allowing for a tightening pressure gradient. Consequently, expecting
breezy conditions with southerly winds generally at 10-15 mph with
wind gusts up to 25 mph as diurnal mixing maximizes during the
afternoon. Overall, with the upper-level ridge beginning to move
into the region, expecting high temperatures to warm marginally but
likely will remain in the 60s tomorrow.
Unseasonably Warm Temperatures Through Wednesday:
The first half of next week continues to suggest a very strong
signal for well above normal temperatures. As the aforementioned
upper-level ridge moves overhead, a continuously tightening south to
north surface pressure gradient will enable strong southerly flow
both keeping conditions breezy for Monday and aiding in warming
temperatures. As a result, the deterministic NBM and its
corresponding percentile data keep high temperatures in the upper
60s and lower 70s with minimal deviation across the percentile
groups. Additionally, with fairly robust 850mb moisture transport on
Monday evening, expecting dewpoints to increase throughout the day.
As a result, overnight low temperatures are expected to maintain on
the warmer side in the upper 50s and lower 60s which could near warm
low records in spots.
Tuesday really warms up with continued strong southwesterly flow and
surface low pressure continues to deepen to our west. As a result,
expecting temperatures to really crank for Tuesday with high
probabilities (50-70%, 70-90% in river valley locations) within the
26.07z NBM of reaching 80 degrees or higher late Tuesday afternoon.
This is further supported by the 26.00z EFI which has values of 0.9
to 0.95 suggesting temperatures towards the highest percentiles of
model climatology. To illustrate how unusual this is for our region,
if this setup had occurred just 3 days later on November 1st,
we would likely be breaking all-time monthly records for
November. Regardless, with these anomalously warm temperatures
expected, daily record temperatures will be challenged, see
Climate section for more details. Overnight temperatures will
remain warm with very strong moisture advection coupled with the
warm air advection. As a result, overnight lows across guidance
only fall into the 60s with even the 26.00z grand ensemble
(GEFS/EC ensemble/Canadian ensemble) having a 20-50% probability
that temperatures do not fall below 70 by 7am on Wednesday.
Wednesday remains the most uncertain day for temperatures as there
are differences on when a surface cold front progresses through the
region. The deterministic 26.12z GFS and EC illustrate this
with the GFS favoring more Wednesday morning and early afternoon
with the EC favoring later into the afternoon and evening. As a
result, noting huge differences in guidance for daytime high
temperatures for Wednesday with an increasing tendency for a
later frontal passage at this time in ensemble guidance.
Consequently, have kept with the national blend for highs in the
60s further northwest and warming into the 70s the further
southeast you get.
Rain Chances Increase This Week, Highest Chances Wednesday:
This active pattern for next week brings some chances for
precipitation as well. Monday evening shows some potential (20-40%
east of the Mississippi River) for shower activity with a relatively
weak nose of 850mb moisture transport pushing into the region later
into the evening hours. However, both very weak instability (under
150 J/kg of MUCAPE in the 26.12z GFS) and minimal deep layer shear
with the aforementioned upper-level ridge axis overhead should keep
the thunderstorm threat to a minimum.
Tuesday evening and overnight becomes more interesting as a
developing surface low to our west begins to lift north of the
region enabling strong 850mb transport to advect northward
within the corresponding warm sector. As this occurs, weak and
capped instability (250-500 J/kg of MLCAPE) is currently progged
in the 26.12z GFS. Robust shear profiles will be present with
strong southwesterly flow aloft. As a result, the 26.00z grand
ensemble (GEFS/EC ensemble/Canadian ensemble) has 70-90% of over
50 kts of sfc to 500mb shear north of I-90. Lots of questions
with this setup still though both with track and intensity of
this surface low not being resolved. Additionally, instability
profiles remain weak and likely capped within the 26.00z grand
ensemble member soundings (100-500 J/kg of MUCAPE across the
25th to 75th at KRST). With similar parameters likely in place
for Wednesday, convection and will be possible with the cold
frontal passage. However, as stated earlier, there remains a
large degree of spread in the timing of its passage which would
have implications for any convective trends. As a result,
confidence for any severe potential remains low at this time for
Tuesday evening through Wednesday.
Regardless, this system has a fairly strong probability for bringing
meaningful precipitation for portions of the region Tuesday night
and Wednesday. This is reflected in the 26.00z grand ensemble with
robust probabilities (40-80%) for over 0.1" across the area. Worth
noting that the EC really favors the heavier totals further east
with convective development and peak heating at this time and
keeping lighter amounts west of the Mississippi River due to the
later frontal timing. Either way, with the 26.00z NAEFS integrated
WV Transport percentiles paints much of the area in the 99.5
percentile suggesting very strong moisture advection into the region
along with precipitable waters of around 1.25". As a result, would
not completely discount the areawide lower probabilities (10-20%) of
over an inch of QPF in the 26.00z grand ensemble.
In summary, confidence is high that temperatures will challenge
daily temperature records early next week, especially on Tuesday.
Confidence remains less clear on precipitation and convection
potential but there is higher confidence for at least some
precipitation areawide with low confidence on any severe potential.
&&
.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1055 PM CDT Sat Oct 26 2024
Surface high pressure pushes southeast through eastern Illinois
at 27.06Z TAF issuance resulting in winds turning south. The
high continues to exit southeast overnight into Sunday morning,
allowing winds to turn south-southwest. A tightened surface
pressure gradient will also increase winds through Sunday.
Highest winds expected west of the Mississippi River from
northeast Iowa into southeast Minnesota, sustained near 15kts
gusting up to 25kts. Elsewhere, from western into central
Wisconsin, winds sustain below 15kts (~12kts) with gusts up to
20kts. Increased winds expected to slightly wane post diurnal
heating Sunday night.
&&
.CLIMATE...
Issued at 152 PM CDT Sat Oct 26 2024
Based on current forecast, daily high records may be challenged at
La Crosse and Rochester this upcoming week. Below are the daily
temperature records that could be broken:
* - Near record to record temperature forecasted
La Crosse
Date Record High Forecast High
----- ----------- ---------------
10/28 75F(1945) 69F
10/29 81F(1937) 80F*
Rochester
Date Record High Forecast High
----- ----------- ---------------
10/28 72F(1945) 70F*
10/29 80F(1950) 81F*
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...Naylor
AVIATION...JAR
CLIMATE...Naylor
Area Forecast Discussion
National Weather Service Shreveport LA
930 PM CDT Sat Oct 26 2024
...New UPDATE...
.UPDATE...
Issued at 919 PM CDT Sat Oct 26 2024
As of 9:15 PM CDT, temperatures are falling into the upper
60s/middle 70s under mostly cloudy skies as a meandering frontal
boundary drifts further into the Ark-La-Tex. Light winds and some
moist air bunched up against the frontal boundary will once again
allow for more patchy fog development across Deep East Texas and
along the I-20 corridor. With weather and observed trends
continuing as anticipated, forecast grid adjustments were not
necessary at this time. /16/
&&
.SHORT TERM...
(This evening through Sunday Night)
Issued at 203 PM CDT Sat Oct 26 2024
Another nice warm day for our Four-State area with partly cloudy
skies area wide. A nice cu field, but still likely a midlevel
inversion capping lift off for now. The old KSHV 88D radar is
still dusty with just a few showers over SW AR. The HRRR is
hopeful for some development over E TX and our I-30 corridor. Then
shifting eastward overnight for areas mainly north of I-20 and
tailing out early on Sunday. The SPC has a swath of general risk
over the midSouth including much of our area in their day one.
Our winds are still east for Idabel and DeQueen right now with
slightly drier upper 50s dew points into central AR. We will not
see any exchange of air mass with light speeds and generally a bit
more cloudiness to start the day. And yes south of I-20 a little
more fog in the offing around daybreak. Highs on Sunday will only
be slightly cooler and our winds will veer early back to SE as the
1030+mb air mass slides from the midWest into the Oh River
Valley. Then again a couple of upper 50s and a range of mostly low
to mid 60s with no rain, but some patchy light fog to start the
new week. /24/
&&
.LONG TERM...
(Monday through next Friday)
Issued at 136 PM CDT Sat Oct 26 2024
The upper level pattern will see a flat ridge over most of the
country east of the MS River, while the west will see a dynamic
trough edging over S CA and the desert SW as the Baja upper high
starts strong in the week, with falling heights over time and a
shift down into Mexico during the week. By midweek the upper ridge
over the Carolinas will hold around 591dam with SW flow edging
slowly over TX and OK. The long wave trough will dampen the Mexico
upper ridge completely with falling heights in the SW flow pattern.
So, it is still looking warm and dry to start the work week, but
clouds will soon gather with the SW flow, and eventually more and
more rain areas will nudge in over our Four-States during the week.
The chance for better rain will wrap up the month and kick start
November with a lingering wet pattern. Of course, this is just a
start what is generally our rainy season. The WPC amounts continue
with an inch or two along our I-30 corridor with less than one
inch amounts down over our Parishes on their day 6. So suffice it
to say, little effect on the drought or burn bans, but more to
come in November is likely. Our air temperatures will settle down
closer to averages by mid to late week with some highs in the 70s
and lows in the 50s north and lower 60s south as we are not expecting
the usual clear cool night pattern, but rather a blanketing of
clouds extending into next weekend as the rain lifts back to the
north, until a bowling ball drops into the long wave trough,
deepening and fortifying it for more SW flow action for us the
following week. /24/
&&
.AVIATION...
(00Z TAFS)
Issued at 614 PM CDT Sat Oct 26 2024
While VFR conditions are anticipated for the entire TAF period,
there was some uncertainty regarding convection this evening. I
did not introduce any VCTS or TSRA given the limited confidence.
Additionally, I did not introduce FG or BR overnight given a lack
of confidence as well.
/44/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 64 86 64 89 / 20 10 0 0
MLU 60 86 59 88 / 20 10 0 0
DEQ 59 79 57 87 / 20 10 0 0
TXK 60 81 62 88 / 30 10 0 0
ELD 56 81 57 87 / 30 10 0 0
TYR 63 87 64 89 / 10 10 0 0
GGG 62 86 63 88 / 30 10 0 0
LFK 64 88 61 87 / 0 0 0 0
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
SHORT TERM...16
LONG TERM....24
AVIATION...44