Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/18/24
Area Forecast Discussion
National Weather Service La Crosse WI
959 PM CST Sun Nov 17 2024
.KEY MESSAGES...
- A strong weather system will bring 1-1.5 inches of rain Monday
afternoon into Tuesday morning to the area and potentially
wind gusts of 35 to 40 mph Monday night. Worst case scenario
rainfall amounts seem to be in the 2-2.25" range with a
preference in southwest WI.
- Cooler temperatures move in mid week, with chances (40-60%)
for light rain/snow showers across the area. Cooler (but seasonal)
conditions continue into the weekend.
&&
.DISCUSSION...
Issued at 256 PM CST Sun Nov 17 2024
Monday and Tuesday`s Rain and Wind Forecast:
Early this afternoon skies were clearing over much of MN/WI as
Canadian low pressure shifts away from the area. A more moist
airmass and southwesterly flow remains near a surface frontal
boundary from Oklahoma into northern IL. Some lingering mid-high
cloud will shift out of the area into the evening making for a
mainly clear sky tonight. 19Z GOES water vapor depicts the deep area
of low pressure over the Gulf of California with the southwest flow
ahead of it rooted in the sub-tropics. Precipitable water values in
the moist airmass over KS/OK/MO were in the 1" range per 17.12Z
upper air soundings and GOES estimates were closer to 1.25"...thus
the RAP forecasts are a bit high currently. Surface low pressure is
forming now near El Paso TX.
GOES imagery loops show the trough over Mexico starting to eject
northeast, shifting into the Upper Mississippi river valley later
Monday. Good model consensus remains that this negatively tilted
trough will bring near record precipitable water /1.25-1.50"/
northward Monday, peaking in the late evening hours. This moisture
stream is co-located with a strong 850mb moisture transport
convergent surge in the evening hours, when precipitation rates will
be maximized. This all in concert with increasing QG forcing aloft.
Thus, confidence is high in rain spreading north during the day
Monday.
Rainfall amounts through Tuesday noon have remained stable for the
most part with good consensus on 1-1.5", although the 17.12Z HREF
guidance suggests there may be a preference of higher amounts toward
2" in southwest WI and far northeast IA. This is in an area of RAP
forecast non-zero MUCAPE and toward the higher incoming precipitable
water source. The 17.12Z HREF PMM suggests 1.5-1.75", with a Max in
the 2-2.25" range, in that same area. This matches the NBM 90th
percentile well which suggested ~2". One limiting factor to amounts
much over 2" is that the system is progressive. The 17.00Z ECMWF
ensemble EFI/SOT suggests the anomalous rainfall amounts have
stronger signal west of the area. Thus, amounts of 2-2.5" seem to be
a good worst case scenario. Would expect within bank river rises,
with the potential for slightly greater river rises in southwest WI
/Kickapoo/. The morning river forecasts did have the Kickapoo in
action stage (Pre-flood). With minimal CAPE and what appears to be
all warm convectively unstable cloud, thunder is not in the
forecast.
With the low pressure tracking into northwest IA Monday night, the
surface pressure gradient is enhanced with the low-level wind field
increasing and gusting. The 17.12Z HREF 925mb wind field shows an
axis shifting through during the evening and overnight from
southwest to northeast of 30-50% probabilities of greater than 45
kts at 925mb...highest northeast of La Crosse. The HREF also has 60-
70% probabilities for over 45 mph surface wind gusts in that axis
shifting through...which seems high. The soundings from the HREF
members are bi-model in their boundary layer stability - some
unstable and mixed (gusty!) and others stable in the rain. There is
a moderate surface pressure rise/fall couplet, but have seen
stronger. Thus, confidence in the wind gust potential Monday night
is lower, but did increase the gusts a bit and think that
northcentral WI seems to have the better gust >45 mph potential.
Additional Light Rain/Snow Showers Wednesday, Cooler Mid to
Late Week:
Rain will continue to exit to the north through early Tuesday, with
guidance suggesting a lull/drier condition for late Tuesday. While
winds might weaken slightly, gusty conditions should continue for
Tuesday. Model guidance shows the aforementioned upper level low
merging with an incoming trough on Tuesday and developing into a
large upper level low. This system is then forecast to track
across our area on Wednesday and into the Ohio River Valley on
Thursday. Much cooler air filters in for Wednesday, with
additional light precipitation wrapping around and keeping
chances in for rain/snow showers. With the warmer ground, time
of day, and light amounts thinking it might limit accumulations
(perhaps a few could see light accums on grassy surfaces). There
still remain some differences between members of the ECMWF and
GEFS on the location of surface low pressure to the east, which
in turn is showing some impact on how much if any additional
precipitation chances linger into the day on Thursday.
Otherwise, as that system continues to push further eastward
ensemble solutions hint towards a return of drier conditions to
start the weekend.
The cooler temperatures, albeit much closer to normal than we have
been seeing, look to remain through the end of the week and into the
weekend. Highs in the mid 30s to low 40s with lows in the 20s to low
30s are currently forecast. The addition of continued gusty winds
through at least Thursday might add on to make a much cooler
feel.
&&
.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 951 PM CST Sun Nov 17 2024
While exact timing still remains a bit uncertain, conditions
are still expected to deteriorate to at least IFR southwest to
northeast after 18z Monday as light to moderate rain overspreads
the region. After 00z, additional potential concern arises
courtesy of low level wind shear due to the presence of 30-40
knot winds above 1500 feet. At this time, current thinking is
that surface gusts will remain strong enough for LLWS to remain
below 30 knots but if surface winds underachieve, will need to
add this to the TAF.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...Baumgardt/EMS
AVIATION...Ferguson
Area Forecast Discussion
National Weather Service Fort Worth TX
611 PM CST Sun Nov 17 2024
...New Short Term, Aviation...
.KEY MESSAGES...
- Widespread showers and thunderstorms are expected tonight
through Monday morning. Damaging winds and brief tornadoes will
be possible with the strongest storms.
- Cooler weather is expected during the latter half of the week,
but above normal temperatures will prevail during the upcoming
weekend.
&&
.SHORT TERM... /NEW/
/Tonight through Monday Night/
A brief period of active weather has commenced across Central and
North Texas this evening and will continue for the next 18 hours
or so. An initial wave of warm advection ascent is spreading
through Central Texas this evening where the latest RAP objective
analysis shows a well defined high theta-e axis across our
southeast counties. Strengthening low level flow is also helping
to maximize the 925-850 mb moisture transport in this area and as
a result we`ve seen a blossoming of showers and a few
thunderstorms. This area of precipitation is expected to expand
in coverage and spread north through the late evening hours as the
low level jet strengthens. While removed from the stronger forcing
ahead of a powerful upper trough which remains to our west, there
is a pocket of around 1000 J/kg of surface based instability
across our southeast counties where this convection is occurring.
Dewpoints have climbed into the lower 70s to the southeast of the
Metroplex. While shear profiles aren`t maximized to their
potential at this time, conditions are a little more favorable to
support rotating updrafts and perhaps a quick spin up tornado in
this region through late this evening. We`ll continue to monitor
this potential. All of this activity will lift north into the I-20
corridor through late evening.
Later tonight, the aforementioned upper trough to the west will
eject out of northern Mexico and into West Texas and will be
accompanied by a strongly forced line of convection which will
enter our western counties after midnight. This line of showers
and thunderstorms will initially have a damaging wind threat as
the low level jet strengthens to near 60 kt. Downward momentum
transfer should support a severe wind threat across our western
counties late tonight with the strongest cells within the line. In
addition to this threat for damaging wind, there will be a threat
for spin up tornadoes within the line given the strength of the
low level shear and likelihood that some surface based instability
will be available. Instability appears to be the main limiting
factor to a more robust severe weather threat, but we`ll monitor
this given the moisture rich boundary layer and potential that
instability could be higher than currently indicated in any of the
short term model guidance.
The main line of showers and thunderstorms will spread east toward
the I-35 corridor around daybreak and continue eastward through
the morning hours, losing some intensity as it pushes east away
from the stronger forcing aloft. All of this activity will be east
of our area by Monday afternoon with clearing skies and brisk
southwest winds. Some wrap around cloud cover may linger into the
evening north of I-20, but a quiet night is expected Monday night
with lows in the upper 40s and lower 50s.
Dunn
&&
.LONG TERM... /Issued 330 PM CST Sun Nov 17 2024/
/Monday Night Through Next Weekend/
After Monday`s event, another extended rain-free period will
begin. Aside from Wednesday, daytime temperatures will remain
above normal. However, overnight temperatures will be seasonally
cool during the latter half of the workweek.
Monday`s storm system will be ejecting into the Upper Midwest
Monday night, and its associated front in the Southern Plains will
correspondingly lose its forward momentum. Dry advection will
result in more pleasant humidity on Tuesday, but weak thermal
advection will mean that afternoon temperatures will reach the
70s across nearly all of North and Central Texas. However, the
passage of a longwave trough through the Plains will usher in a
stronger front Tuesday night. Wednesday will be noticeably cooler,
but the pattern won`t allow the coldest air to reach our latitude.
Sunshine and dry air should allow Wednesday afternoon temperatures
to top 60F. The mercury will dip into the 30s both Thursday and
Friday mornings. Wind speeds are looking more favorable for some
low-lying and outlying spots to see some colder readings. We will
continue to assess the potential for frost or an isolated freeze,
but neither looks likely. A warming trend will return 70F+
temperatures to the entire region during the upcoming weekend.
25
&&
.AVIATION... /NEW/
/00Z TAFs/
Scattered showers and a few thunderstorms are increasing in
coverage to the south of the D10 airspace this evening. This trend
is expected to continue through midnight with cigs eventually
lowering and widespread showers becoming likely. We`ve started the
TAFs off VFR with VCSH, but widespread MVFR cigs should become
likely in the next hour or so with precip chances increasing. An
initial wave of showers and perhaps a few TS will linger through
about 6-7Z before a little lull ahead of the main line of storms
late tonight and early Monday morning.
We`ll continue to lower cigs overnight to IFR after 7Z with timing
of thunderstorms associated with the main line between 13-15Z.
Gusty south winds will occur ahead of the line and become
southwest behind the line of storms. Condition swill improve late
Monday morning with VFR prevailing by afternoon.
Dunn
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 65 73 51 71 45 / 100 100 0 0 0
Waco 65 76 48 75 46 / 80 100 0 0 0
Paris 65 73 48 71 42 / 80 100 0 0 0
Denton 63 72 47 71 40 / 100 100 0 0 0
McKinney 64 73 49 72 42 / 100 100 0 0 0
Dallas 65 73 52 72 46 / 100 100 0 0 0
Terrell 65 74 49 73 44 / 90 90 0 0 0
Corsicana 67 76 51 75 47 / 90 80 0 0 0
Temple 63 78 48 79 44 / 60 100 0 0 0
Mineral Wells 61 72 46 72 39 / 100 100 0 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Goodland KS
720 PM MST Sun Nov 17 2024
.KEY MESSAGES...
- Rain is forecast to move through the area tomorrow. Locales
generally along and east of a line from Norton to Oakley could
see an inch or more of rain with much of the rest of the area
seeing a few hundredths to a few tenths. There is forecast to
be a fairly sharp gradient in rainfall amounts for the area.
- Winds are forecast to increase to 15-30 mph with gusts to 45
mph for much of Monday through Wednesday. Near 0F wind chills
possible Wednesday morning in the western CWA.
- Mild conditions are forecast for the end of the week.
&&
.UPDATE...
Issued at 707 PM MST Sun Nov 17 2024
Guidance continues to suggest a small shift to the east so have
cut back pops across western portions of the area some more. It
is a bit tricky to to nail down where the sharp gradient of rain
vs no rain will be but confidence is increasing it will set up
within the vicinity of a Hitchcock to Sherman to eastern
Cheyenne (CO) line. The ECMWF continues to do its own thing with
a more western path which would increase the rain chances but am
noticing that more ensemble members are trending east. So can`t
completely rule out that scenario but is looking less likely. I
did add in some thunder mention as well across the east as we
will be near the dry slot region of the low, but in somewhat
similar fashion to the low last week do think we can get some
convection within that region. Some guidance also does try to
suggest some stronger storms with 50+ mph wind in that
convection so may need to watch for a rogue 60 mph wind gust
around Graham/Norton/Gove counties Monday afternoon; confidence
in that occurring is around 10%.
The other change I made was to add in slight chance snow and
rain/snow for Tuesday morning. RAP and NAM both have an increase
in mid level moisture Tuesday morning and persisting west to
east across the area into early to mid afternoon. The moisture
is co-located along a 700mb FGEN band which will further help
increase lift. Snow looks to be the primary precipitation type
before turning to a more rain/snow mix as it moves further east
and temperatures warm slightly. Despite the strong signal in mid
level moisture the only thing precluding slightly higher pops is
that we will be having drier air at the surface moving in.
Should this dry air move in quicker then this may just be
flurries at best. Should this occur and more cloud will linger
which was the NAM is suggesting then high temperatures will
need to be lowered.
&&
.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 1236 PM MST Sun Nov 17 2024
Current satellite observations show a low/trough near the Baja
Peninsula with a larger trough beginning to push into the Northwest.
Ahead of these features, moisture is streaming across the Southern
Plains, with a few showers located just south of the Tri-State area.
With these features pushing east, the showers should stay south of
the area and allow the Tri-State area to stay mostly sunny with
temperatures in the 40`s and 50`s. Tonight, the upper low near the
Baja Peninsula is forecast to begin pushing northeast and bring a
surface low up from the south as well. With this, cloud cover is
forecast to increase with a few showers possible along and south of
Highway 40. Temperatures are forecast to drop into the 20`s and 30`s
before the cloud cover moves in, and then stabilize. Winds will
begin shifting to out of the northwest as the surface low nears the
area.
Tomorrow, the upper low and surface low are forecast to move through
Kansas. With the moisture wrapping around the upper and surface low,
cloudy skies are expected for most of the day with maybe some
sunshine peaking through for counties along the Colorado border. The
tracks as a whole have shifted east compared to prior forecasts.
This has lowered confidence in the area receiving the higher rain
totals and also lowered confidence that western portions of the area
will see any rain at all. The current forecast is for around half an
inch to an inch of rain from Norton to Oakley and locales east. The
rest of NW Kansas and SW Nebraska would likely see only a few
hundredths, to maybe half an inch. While the current deterministic
guidance and ensemble guidance favor the eastern track, there are
still a few solutions that track slower or further west and allow
for main rainfall in the area. Overall chances for the higher
amounts (1-2" in the east and 0.5-1" for much of the rest of the
area) is currently around 20%. Currently, there is little to no
concern for wintry precipitation with dewpoints forecast to
generally be above freezing, and with a large enough warm layer near
the surface to melt any frozen hydrometeors into rain. Little to no
precipitation is expected where there may be a chance for freezing
rain to develop (generally near the Colorado border and west). Even
with the more westerly track, the warmer near surface area and
higher dewpoints would also shift west and keep the chance very low
for freezing rain or frozen precipitation.
Highs are forecast to generally stay in the 40`s, as temperatures
may not move much during the day with persistent cloud cover and
little temperature advection. Winds are forecast to increase through
the day with the surface low moving nearby. However, the winds above
20 mph and wind gusts above 30 mph may stay confined to Highway 25
and east as the further east track keeps the stronger pressure
gradient over Central Kansas, and less into the Tri-State area. For
the locales with the stronger winds, gusts up to 45 mph are forecast
through much of the daytime hours. There is about a 15% chance for
occasional gusts around 50-60 mph, depending on if the showers can
help bring the stronger winds aloft to the surface.
Tomorrow night, winds are forecast to stay around 10-20 mph with
gusts to 40 mph as the pressure gradient remains fairly compact with
the surface low nearby and with the second upper trough forecast to
swing through the Northern Rockies. Lows are again forecast to reach
the 20`s and 30`s.
Tuesday is forecast to be a fairly cool day as higher pressure
builds in from the northwest while the second upper trough swings
through the Northern Plains. While the better moisture and forcing
will likely be east of the area, there is around a 5 to 10% chance
for a few rain or snow showers depending on how much moisture
lingers as the upper trough axis swings through the Plains.
Otherwise, a mix of sunny and cloudy skies along with the cooler air
mass are forecast to keep highs generally in the 40`s. With the
second trough axis swinging through and the higher pressure moving
into the area, winds are forecast to remain a bit strong at 15-30
mph with gusts to 45 mph. Winds are forecast to remain fairly strong
into Tuesday night, but with skies clearing as the upper trough
begins to push off to the Great Lakes region. Even with the breezy
winds, the drier air pushing in with cold air mass is forecast to
have low temperatures drop into the teens and 20`s. Winds chills
could drop into the single digits for the first time this year.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Issued at 1236 PM MST Sun Nov 17 2024
For the long term, a fairly mild patter is forecast for the
remainder of the work week. With the upper troughs pushed off, the
rest of the week is forecast to see some ridging aloft. With this,
the winds should weaken by Wed/Thu and temperatures moderate. Highs
are forecast to generally be in the 50`s and 60`s with lows in the
20`s and 30`s.
This pattern may persist through the weekend, but some guidance is
hinting at a shortwave trough moving through the Rockies. This could
provide a chance for some precipitation and cooler temperatures, but
nothing too exciting at this time.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 400 PM MST Sun Nov 17 2024
VFR conditions are forecast to start the period with southerly
winds around 05-08 knots. Clouds will then begin to increase in
coverage overnight as a system approaches the area. Best
potential rainfall looks to occur after 18Z with the highest
confidence in KMCK; a sharp gradient in the rainfall will be in
place so will maintain the prob30 for KGLD. Winds will also
become breezy as well throughout the day Monday. Continuing with
the AMD NOT SKED for KMCK due to the visibility concerns at KMCK
as a visibility issue with the ASOS sensor continues.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...None.
CO...None.
NE...None.
&&
$$
UPDATE...Trigg
SHORT TERM...KAK
LONG TERM...KAK
AVIATION...Trigg
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
859 PM CST Sun Nov 17 2024
.KEY MESSAGES...
- Rain on Monday will be accompanied by gusty winds. There is a
medium probability (60% chance) that gusts will exceed 45 mph
Monday evening, primarily in areas west of Interstate 55.
- A sharp cool down will arrive by midweek, signaling the return
of below-normal temperatures.
&&
.UPDATE...
Issued at 859 PM CST Sun Nov 17 2024
Updates this evening to slow the arrival of low chances of light
precipitation a couple of hours, but otherwise forecast looks on
track to spread widespread rain into the area near sunrise as
moist warm advection develops ahead of an approaching low. The
first sprinkles could develop as early as 1 am. Have also raised
lows for tonight, as we have likely already seen the lowest
temperatures of the night in the lower to mid 50s, and
temperatures should subtly increase the remainder of the night.
37
&&
.DISCUSSION...
Issued at 128 PM CST Sun Nov 17 2024
A surface low, currently positioned over central Ontario, has
filled and weakened with a diffuse cold front extending from
roughly Milwaukee to Davenport to Kansas City. A narrow band of
light rain has developed in the vicinity of the front, with
sprinkles and patchy drizzle being observed well out ahead of the
front within a broad area of warm/isentropic ascent.
The cold front will stall-out over central Illinois tonight as
the upper-level forcing becomes displaced too far east. With a
strong push of warm/isentropic ascent impinging on the stationary
boundary, we should see areas of low stratus and patchy drizzle
develop overnight. Model guidance is then in excellent agreement
of resurrecting the stationary boundary as a warm front by Monday
morning, lifting it back northward as a strong shortwave trough
ejects out of the Southern Rockies and kicks off rapid cyclogenesis
over the Plains. A robust influx of moisture surging northward
from the western Gulf will advect anomalous PWATS (> 1.5") into
central Illinois ahead of the frontal system. With strong synoptic
ascent juxtaposed to the moisture-laden airmass, we should see
another beneficial rainfall across much of the region. The latest
HREF LPMM QPF guidance supports between 0.25"-1" in areas north of
I-70.
Perhaps more impactful than the rain will be the wind. With the
deepening surface low lifting across central Iowa by Monday
evening, we should begin to experience synoptic gusts greater than
30 mph. Hi-res guidance remains fairly bullish with peak gusts,
with the deterministic HRRR and NAMNest offering a broad area of
45+ mph gusts accompanying showers along the cold front Monday
evening. Model soundings suggest this might be overdone, with a
stable layer likely limiting momentum transfer during the evening
hours. The more likely window for gusts exceeding 45 mph looks to
come late Monday night into early Tuesday morning as the occluded
front lifts across west central Illinois. By this time, the low-
level jet core won`t be quite as strong, but low-level lapse rates
appear to steepen, making the boundary layer unstable, and
augmenting vertical momentum transfer. At this point, confidence
and duration of enhanced gusts remains low enough to preclude a
Wind Advisory, but we will continue to monitor trends.
Attention then turns to Wed/Thu as the frontal system occludes and
phases together with another shortwave digging out of the Pacific
Northwest. Model trends have been for the upper-level low to be
further east and not quite as deep, resulting in a slightly less
impactful event for central Illinois. The CMC and its envelope of
ensemble guidance continues to be the outlier with the cold push,
though the ECMWF/EPS still hangs onto a glancing blow of cold
temperatures late next week. At this point we couldn`t rule out
some scattered snow showers along the I-74 corridor during the
Wed/Thu timeframe, but anything impactful continues to trend east
of our area.
At this point, temperatures into next weekend are not looking as
cold either. If anything, the deterministic NBM appears
unrealistically cold with its bias-correction solutions coming in
below the 25th percentile of the raw guidance.
MJA
&&
.AVIATION... (For the 00z TAFs through 00z Monday Evening)
Issued at 557 PM CST Sun Nov 17 2024
Cigs and vsbys will lower overnight as a frontal zone stalls out
over the area ahead of an approaching low and interacts with moist
southerly flow. Observations west of KDEC-KBMI show overcast cigs
spreading eastward and approaching MVFR levels, which should
overspread central IL over the next few hours. Further lowering of
cigs overnight should be accompanied by rain showers developing
and becoming widespread by 11Z-15Z, along with IFR cigs. Gradual
improvement in cigs should take place into Monday afternoon,
although MVFR will likely continue. Winds S 4-8 kts initially,
becoming SE around 15 kts overnight. SE winds will increase Monday
morning, becoming SE 12-16 kts, with gusts around 25 kts by
18Z-20Z.
37
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service New Orleans LA
529 PM CST Sun Nov 17 2024
...New AVIATION...
.SHORT TERM...
(This evening through Tuesday)
Issued at 235 PM CST Sun Nov 17 2024
Key message...heavy rainfall event looks to be developing for
roughly the eastern 2/3 of our CWFA for Monday night into Tuesday.
Upper ridge centered over the eastern Gulf of Mexico this
afternoon with a deep upper trough near the Arizona-Mexico border,
and weakening Tropical Depression Sara over the Yucatan Peninsula.
At the surface, high pressure was centered over the Carolinas with
a frontal boundary extending from the Great Lakes to west Texas.
Southeast winds were bringing moisture from the Gulf across the
area underneath an inversion around 5,000 feet. Partly to mostly
sunny skies were noted across the area at mid afternoon with
temperatures ranging from the upper 70s to mid 80s. Dew points
were in the lower and middle 60s.
Sara is expected to weaken and eventually dissipate over the
Yucatan during the next 24 hours, at least as a tropical system.
As the upper ridge shifts east to Florida and the upper trough
lifts northeastward from Arizona through the Plains States, some
or most of the moisture from the remnants of Sara will get pulled
northward tomorrow and tomorrow night on 850 MB winds of 40+
knots. This airmass will be unusually moist for mid-November, with
both the GFS and HRRR forecasts indicating precipitable water
values in the 2.2 to 2.5 range across about the eastern half of
the area ahead of the front Monday night and Tuesday morning. It
should be noted that the LIX upper air sounding climatology base
at SPC doesn`t include any soundings with precipitable water
values exceeding 2.2 inches beyond November 3rd.
Tonight and most of the daytime hours Monday are actually expected
to remain dry with precipitable water values near or below 1 inch.
Conditions will get somewhat breezy during the day on Monday with
sustained winds near 20 mph. At this point, don`t plan on a Wind
Advisory. Rain and thunderstorms are expected to become more
numerous during Monday evening with the primary threat between
midnight Monday night and noon Tuesday. While shear would be
sufficient for strong to severe storms, current forecast soundings
indicate that instability will be rather weak. Forecast rain
amounts of 3-5 inches across a portion of the local area look to
be entirely reasonable with isolated much higher amounts possible.
The one potential failure mode would be if strong storms were to
develop over the Gulf off the Louisiana coast and cut off the best
moisture inflow. With the potential for significantly heavy
rainfall over multiple large urban areas, have opted to issue a
Flood Watch for Monday night through noon Tuesday, generally from
about Hammond to Houma eastward. Later adjustments in areal extent
or timing may be necessary.
Minor coastal flooding will again be an issue tonight during the
high tide cycle on east and southeast facing shorelines. Generally
less than a foot above normally dry ground during high tide
tonight. With the increase in wind speeds on Monday, that`s
likely to push somewhat more water into prone places, with current
guidance indicating 1-2 foot inundation possible. Have issued
another Coastal Flood Advisory for tomorrow night. Didn`t have
enough confidence in water levels to justify a watch or warning.
Much above normal temperatures to continue through the daytime
hours on Tuesday with low-mid 80s not out of the question,
depending on cloud cover. Cold air likely to lag the frontal
passage by 6-12 hours across the area. If we get several hours of
sunshine Tuesday afternoon, even with northerly winds, guidance
may not be high enough.
&&
.LONG TERM...
(Tuesday night through Saturday night)
Issued at 235 PM CST Sun Nov 17 2024
The good news is that once the moisture gets swept out of the area
Tuesday, that pretty much ends any significant threat of
precipitation for the rest of the forecast package. A trailing
shortwave moving through the western Great Lakes Tuesday night
into Wednesday will usher in significantly cooler and drier air to
the area for the 2nd half of the week into next weekend.
The northern half of the area could see multiple nights with
overnight lows falling into the upper 30s, beginning Wednesday
night. Thursday into Saturday could see high temperatures falling
short of the 70 degree mark, especially on Friday. Our local area
hasn`t seen temperatures that cool since mid March for most of the
area.
&&
.AVIATION...
(00Z TAFS)
Issued at 526 PM CST Sun Nov 17 2024
For the majority of the forecast period, VFR conditions will
remain in place as drier air lingers over the region. However, a
surge of moisture will feed into the area after 20z, and this will
support the development of MVFR stratus ranging from 1500 to 2500
feet at HUM, MSY, and NEW by 22z. At MSY, further stratus build
down is expected after 00z as moisture continues to stream in, and
light rainfall could develop as early 03z resulting in prevailing
IFR conditions.
&&
.AVIATION...
(18Z TAFS)
Issued at 1133 AM CST Sun Nov 17 2024
Moisture trapped under an inversion near 850 mb will continue to
produce areas of broken clouds between FL025-035 over the next 24
hours. Don`t expect to see ceilings much below FL020 until very
close to 00z Tuesday, if that soon. Southeast winds 10 to 15 knots
should continue through about mid-morning Monday. As pressure
gradient tightens beyond that point, sustained winds will increase
to 15 to 20 knots at most terminals with occasional gusts above 25
knots. Any significant threat of TSRA is not expected until 00z
Tuesday or later.
&&
.MARINE...
Issued at 235 PM CST Sun Nov 17 2024
Will continue the Small Craft Advisories and Exercise Caution
headlines as currently depicted through Monday night with the
likelihood that they will be extended in later forecasts. While
there may be short periods where headlines might not be justified,
marine interests should anticipate hazardous conditions,
especially over the open waters, through much or all of the
workweek.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 61 80 68 80 / 0 20 100 60
BTR 67 85 72 84 / 0 30 100 50
ASD 64 82 71 81 / 0 20 90 80
MSY 68 83 73 81 / 0 30 90 80
GPT 67 80 70 79 / 0 10 80 90
PQL 63 83 72 81 / 0 10 70 100
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Flood Watch from Monday evening through Tuesday morning for
LAZ039-058>060-064>071-076>082-087>090.
Coastal Flood Advisory until 6 AM CST Monday for LAZ058-060-
066>070-076>078-080-082-084-086-087.
Coastal Flood Advisory from 6 PM Monday to noon CST Tuesday for
LAZ058-060-066>070-076>078-080-082-084-086-087.
GM...Small Craft Advisory until 6 AM CST Tuesday for GMZ550-552-555-
570-572-575-577.
MS...Flood Watch from Monday evening through Tuesday morning for
MSZ077-083>088.
Coastal Flood Advisory until 6 AM CST Monday for MSZ086>088.
Coastal Flood Advisory from 6 PM Monday to noon CST Tuesday for
MSZ086>088.
GM...Small Craft Advisory until 6 AM CST Tuesday for GMZ552-555-570-
572-575-577.
&&
$$
SHORT TERM...RW
LONG TERM....RW
AVIATION...PG
MARINE...RW
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
538 PM CST Sun Nov 17 2024
.KEY MESSAGES...
- Widespread soaking rainfall Monday afternoon into Tuesday morning.
An inch or so of rain appears likely at most locations.
- Colder air arrives for the middle of the week, with some snow
accumulation possible across western Minnesota Tuesday night
through Wednesday.
- Temperatures will be much colder by the end of the work week, with
highs in the 30s and lows in the 20s.
&&
.DISCUSSION...
Issued at 221 PM CST Sun Nov 17 2024
Visible satellite reveals clear skies across south central Minnesota
and western Wisconsin. Afternoon highs are on track to top out well
above normal, in the upper 40s to low 50s. WSW winds will
occasionally gust to around 20 mph through the afternoon, however
they are expected to diminish heading into the evening. Despite
clear skies tonight, light southerly winds will support
temperatures from falling below the freezing mark in many spots.
RAP forecast soundings have hinted at the possibility of patchy
fog generally along and north of I-94 where winds are forecast to
be the lightest and relative humidity climbs above 90 percent from
just after midnight through daybreak. Confidence is low in the
development of fog, but it will be something to keep an eye on
overnight. Monday will begin calm and dry. Temperatures are
forecast to climb into the low to mid 50s prior to the arrival of
soaking rain through the second half of the day.
CONUS water vapor imagery and 500mb analysis reveal a closed upper-
low currently located over Arizona. The closed low will become
negatively tilted as it lifts northeast over the southern Great
Plains. Broad ascent east of the upper-low will spawn a developing
surface cyclone across Texas tonight. The ~980s mb surface low
pressure system is progged to race north Monday and will bring a
period of region-wide rainfall Monday afternoon through Tuesday
morning. Favorable moisture transport and isentropic ascent will
work in tandem to produce a widespread shield of rainfall to the
north of the surface low. Expected moisture return into the Upper
Midwest remains quite remarkable, with PWATs (1-1.25") near record
values per MPX sounding climatology. Our latest forecast
illustrates the arrival of the rain across southern Minnesota by
early afternoon. Rain will continue to lift northward towards the
I-94 corridor through late afternoon, setting the stage for a
soggy evening commute. The rain will be moderate to heavy at times
through early Tuesday, prior to the arrival of the system`s dry
slot which will bring an end to the rain from south to north
Tuesday morning. Most locations are expected to see an inch or so
of rain, with up to an inch and a half possible. Westerly gusts
will reach speeds between 30-40 mph across western Minnesota
Tuesday.
Forecast guidance continues to come into better agreement with the
range of possible outcomes regarding wrap around precipitation and
potential snowfall on Wednesday. The latest runs of the EPS/GEM
suites remain steadfast on a due north/northwest track and cessation
of the occluding surface low across southern Manitoba. New GEFS
suite has trended further west across the ensemble membership, which
is reflected in the deterministic run as well. The aforementioned
stall of the surface low will allow for northwesterly flow to
transport colder air from southern Canada into the Upper Midwest,
allowing for wrap around precipitation to transition to light snow.
It looks like the best chance for several inches of accumulating
snow will be for locations near the surface low, say across
North Dakota, due to better dynamics. However, curvature vorticity
should provide enough lift to produce snow showers locally. The
best chance for a few inches of snow accumulation will be across
western Minnesota. We don`t expect as much in terms of accumulation
in eastern Minnesota and western Wisconsin, though the combination
of strong northwesterly winds and snow showers will make for a
rather unpleasant day outdoors. We have reflected this potential
with 40-60% PoPs in the grids. The 12z NAM is an outlier in the
data set, with an elongated surface low located further to the
north and east than the scenario captured above. In this solution,
the wrap around precipitation/snowfall are more likely across
north central Minnesota, with dry weather in the south.
The upper-low is progged to translate southeast over the Great
Lakes on Thursday. We`ll keep the chance for a few snowflakes
around early Thursday morning, before the upper-level features
move off to the east. Northwesterly flow will become the
dominating feature in the upper air pattern through the upcoming
weekend, which will drop temperatures into the 30s for highs
and 20s for lows. The forecast appears quiet through Saturday,
but global models have started to hint at a clipper-type system
moving across the northern CONUS roughly a week from now. There
is a long way to go before we can lock in any specifics, but
the expected environment should be cold enough for snow to be in
the discussion if a weather system were to take shape.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 528 PM CST Sun Nov 17 2024
Well, the rain we have been talking about for days early in the
upcoming week has finally made it into the TAF window. The only
fields that may stay dry this period are AXN & STC as rain will
just be moving into those terminals as this period ends. For all
other terminals, a wall of water will move in during the
afternoon. RAP soundings show the possibility of some MVFR cigs
moving in a couple of hours ahead of the rain, but once rains
hit, cigs will quickly drop to IFR levels, with IFR/MVFR vis. As
the rain arrives, east winds will be picking up in strength and
become gusty as well.
KMSP...For nearly 24 hours out, model spread is pretty small
with onset of rain on Monday at either 21z or 22z.
/OUTLOOK FOR KMSP/
TUE...MVFR/IFR. RA Early. Wind WSW 20-25G35 kts.
WED...MVFR. Chance -SHSN/IFR. Wind W 15-20G25-30kts.
THU...MVFR cigs likely. Wind NW 15-20G25-30kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&
$$
DISCUSSION...Strus
AVIATION...MPG
Area Forecast Discussion
National Weather Service Raleigh NC
958 PM EST Sun Nov 17 2024
.SYNOPSIS...
Offshore high pressure will extend across the South Atlantic states
ahead of a strong cold front that will move through the region
Wednesday night.
&&
.NEAR TERM /TONIGHT/...
As of 955 PM Sunday...
A sub-tropical high at the surface and aloft will continue to extend
across the Southeast tonight. Associated calm, to occasional, light,
swly stirring with the center of the surface high off the SC coast,
will favor strong radiational cooling amid passing cirrus. With
another day of modification of the associated airmass, overnight-Mon
morning temperatures will be less chilly/frosty than Sun morning --
by 4-8 F on average-- and mostly in the upr 30s to mid 40s. Low-
level moisture has likely not increased or deepened sufficiently, as
indicated by nearly steady, observed mean mixing ratios at GSO and
MHX for the past couple of days, to allow for anything more than
patchy mist/fog development at the usual AWOS sites and RWI.
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
As of 135 PM Sunday...
Aloft, the sub-tropical ridge will build to the west Mon, then shift
ewd into the area Mon night. At the surface, high pressure will sit
just off the Southeast US coast through Mon night, with generally
weak high pressure over central NC in the wake of a weak trough
exiting to the east early Mon. Winds should initially be wly to nwly
at 3-5 kts during the day, then become more wswly/swly before going
calm overnight. The weather should remain dry through Mon night. As
for temperatures, highs should range from upper 60s to low 70s. As
for lows Sun night, low-level thicknesses are again forecast to be
in the 1360-1375 meter range by 12Z Tue, with cloud cover increasing
from the wnw after midnight. Give the generally calm winds expected,
lows may be similar to perhaps a category higher than tonight,
mainly in the mid 40s.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
As of 318 PM Sunday...
Flow aloft will turn increasingly more swly Tuesday as a strong
upper trough lifts through the TN Valley. The trough and an
associated upper low will then push east across the eastern seaboard
Wednesday through Friday. Behind this feature, strong nwly flow
aloft returns through the weekend.
There continues to be better agreement amongst models wrt to
precipitation chances and QPF middle of this upcoming week. On
Tuesday, light rain will be possible starting in the afternoon and
continuing into the overnight period via increasing isentropic lift
and moisture depth (PWAT will surge to ~250 % of normal through
Tuesday night). SPC has introduced a very small area of the Triad in
a Day 3 Marginal for severe storms (valid 12Z Tuesday through 12Z
Wednesday). As of now, not overly concerned for this area, as any
instability should largely be shunted to our south over the Gulf
States/GA.
By Wednesday, the anomalously moist airmass will linger with
increasing mid-level height falls over our area via influence from
the amplifying cyclonic flow aloft. Dew points are expected to rise
into the lower to mid 60s Wednesday afternoon, and as such models
are hinting at the possibility of some instability developing (CAPE
values are generally less than 500 J/kg amongst models). Given that
bulk-layer shear will be quite potent (35 to 45 kts), we`ll have to
monitor for the potential for isolated severe storms. SPC did note
at least a non-zero, conditional, threat for a few stronger storms
Wednesday with their overnight forecast. PoPs should drop off from
west to east as considerably dry air crashes into our area by
Wednesday night. Mean ensemble QPF amongst ensembles suggest a few
tenths of an inch to a quarter of an inch is possible through
Wednesday night. However, the higher percentiles suggest upwards of
a half to three quarters of an inch maybe possible. This doesn`t
seem out of the realm of possibility, especially if instability can
actually be realized Wednesday.
Persistent nwly flow with strong CAA is expected behind the exiting
upper trough (as the upper low moves overhead Thursday night into
Saturday). As such, a drastic temperature change is expected from
highs in the upper 60s/lower 70s Tuesday/Wednesday to highs
struggling to reach the lower to mid 50s Thursday through Sunday.
The raw NBM is also already suggesting the potential for some quite
cold nights particularly this upcoming weekend. We could see
overnight lows dip near freezing for a good portion of our area.
Dry conditions are generally expected from Thursday through Sunday.
However, some lingering moisture, combined with steep mid-level
lapse rates, may promote sprinkles (and perhaps isolated graupel
reports) Thursday and Friday.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
As of 725 PM Sunday...
Conditions remain VFR this evening with surface high pressure
overhead/just offshore and light southwesterly winds around 4kts or
less. While thin in nature, there is a good amount of high cloud
cover across NC with with even more across portions of TN/AR/MS.
Earlier model guidance was very aggressive showing widespread IFR
fog at INT/GSO/RWI, but this has since backed off a bit, likely due
to increasing high clouds across the area. It seems plausible that
some MVFR vsbys are likely tonight but perhaps not as low as
previously suggested by the likes of the HRRR and NAM. The exception
may be RWI where cloud cover will likely be thinnest and winds
lightest of all the TAF sites. Went with a persistence forecast of
IFR fog at RWI, with only a few hours of MVFR vsbys elsewhere. Any
fog that develops should mix out by mid morning, with only high
clouds in place through the end of the TAF period.
Outlook: A strong cold front moving through the region will bring
widespread rain and associated sub-VFR restrictions to the area late
Tuesday and will linger into the day on Wednesday. VFR conditions
are expected to return late Wednesday afternoon. A deepening area of
low pressure INVOF the Great Lakes will yield frequent gusts of 20
to 30 kts Thursday and again on Friday.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...KC
LONG TERM...Luchetti
AVIATION...Leins/CBL