Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/14/25
Area Forecast Discussion
National Weather Service Bismarck ND
1021 PM CDT Sun Apr 13 2025
.KEY MESSAGES...
- Widespread rain will diminish from northwest to southeast
overnight, but isolated to scattered rain and snow showers
could continue through Monday afternoon, especially over
central North Dakota.
- Strong winds in southwest North Dakota will subside overnight.
Windy conditions are once again expected on Monday, strongest
in south central and eastern North Dakota.
- Dry conditions with temperatures trending warmer Tuesday and
Wednesday, followed by cooler temperatures and increasing
chances for rain Thursday and Friday.
&&
.UPDATE...
Issued at 1018 PM CDT Sun Apr 13 2025
At 10 PM CDT, the upper level was was located between Jamestown
and Fargo. Observed trends were blended into the forecast for
this update. On the western periphery of the low, a deformation
band of precipitation in northwest North Dakota has been slower
to progress eastward than guidance indicated. In addition, there
is now a more well defined band of precipitation streaming
south along the Saskatchewan/Manitoba border. This band is
likely to continue southward through central North Dakota
through the night.
Still seeing a few locations in southwest North Dakota with
sustained winds around 30 to 35 mph and gusts to around 50 mph,
so will allow the Wind Advisory to continue.
UPDATE
Issued at 728 PM CDT Sun Apr 13 2025
At 7 PM CDT, the center of the stacked low was located between
Bismarck and Harvey. Recent satellite imagery shows the low system
beginning to pick up southeastward momentum. We did see a few
thunderstorms during the late afternoon along the Highway 52
corridor from Minot to Carrington, which were prolific producers of
small hail. One storm in Wells County also produced a cold air
funnel cloud around 515 PM CDT. The last storm has shifted into
Griggs County. The threat for lightning, hail, and cold air funnels
has ended in our forecast area.
Wrap-around precipitation has not been as intense or widespread in
the southwest quadrant of the low as expected. In northwest North
Dakota, areas that experienced accumulating snow this afternoon,
mainly in far northern Divide County, have now seen temperatures
rise well above freezing as precipitation gradually winds down.
Still seeing a few snow observations from Mountrail to McKenzie and
Dunn Counties, but near-surface air and wet-bulb temperatures remain
above freezing. Snow could continue to mix in as temperatures begin
to cool this evening, but additional accumulations are becoming less
likely.
The mention of isolated to scattered rain/snow showers from late
tonight through Monday afternoon was made more widespread across the
area for this update. An upper level shortwave trailing the stacked
low is forecast to dig into the western and central Dakotas over
this time period, and CAMs have become more consistent that the
cyclonic flow will produce shower activity. The showers could be
both rain and snow through the morning, transitioning to mostly rain
in the afternoon, but possibly mixed with sleet, graupel, or even
small hail.
&&
.DISCUSSION...
Issued at 334 PM CDT Sun Apr 13 2025
A strong upper low is currently located over northwest North
Dakota with a surface low located over the north central.
Widespread rain will continue across the northern third of the
state as the entire system slides east southeast. Some snow has
also been mixing in at times on the northwest fringe of the
precpitation shield where temperatures are colder.
There has been some dry slotting across the southwest and south
central but clouds have been trying to fill in a bit over the
past hour or two. As mentioned in the previous update, RAP
soundings have been consistent in developing a large pocket of
MUCAPE values ranging from 200 to 500 J/kg, mainly across the
southern half of the state. Simulated HRRR reflectivity would
suggest the potential for some isolated thunderstorms getting
started here in the next hour or two if we can get enough
instability. While severe weather is not expected, cold
temperatures aloft could lead to some small hail and steep low-
level lapse rates could lead to some gustier winds.
Additionally, if enough low-level instability can be realized, a
couple of weak funnel clouds may not be out of the question in
the vicinity of the low where there should be some enhanced
surface vorticity.
The Wind Advisory continues to be in good shape across the far
southwest as we`ve seen several hours here of west northwest winds
in the 30 to 35 mph range and gusts up to 55 mph. Winds should
begin to relax through the evening, but they will remain breezy
overnight across most of western and central North Dakota.
Any thunderstorm activity should relax early in the evening as
the upper low pivots and moves east, bringing some more
widespread stratiform precipitation into the central.
Precipitation should become more isolated to scattered in nature
overnight with some snow mixing in at times. Little to no
accumulation is expected.
The windier conditions will move off to the east on Monday when
we may see some northwest winds close to advisory criteria in
and around the James River Valley. Some consideration was given
to issuing another Wind Advisory for the southeast on Monday,
but a few factors led us to hold off for now. For one, models
are suggesting low level warm air advection and widespread
cloud cover here during the afternoon. Additionally, while a
decent pressure gradient and steep low-level lapse rates are
forecast to be in place, pressure rises are forecast to be weak
to non-existent. Finally, with wind headlines in effect today
and high uncertainty regarding the setup tomorrow, we
collaborated with neighbors and decided to hold off for this
forecast package.
We will likely see some more isolated to scattered showers
develop in the afternoon on Monday as we remain in cyclonic flow
aloft. RAP soundings suggest we will see some more pockets of
MUCAPE in the 200 to 500 J/kg range so a few isolated rumbles of
thunder may not be out of the question. For now, will leave
thunder mention out of the forecast for Monday and see how
today`s setup ends up playing out. Temperatures will remain
cool with highs ranging from the mid 40s to the lower 50s.
We clear out Monday night, giving way to a sunny Tuesday and
warmer temperatures as an upper ridge axis moves across the
state. Tuesday`s highs will range from the lower 50s northeast
to the mid to upper 60s southwest. Wednesday will then be the
warmest day of the week as we transition back into low amplitude
southwest flow aloft. NBM highs are currently forecast to range
from the lower 60s to the lower 70s. Another shortwave then
moves into the region Wednesday night, leading to the next round
of low to medium precipitation chances through at least
Thursday evening (30 to 60 percent). Depending on your guidance
of choice, some low precipitation chances (20 percent) may
linger through the day on Friday. Cooler temperatures start to
move in on Thursday with highs forecast to range from the upper
40s northwest, to the lower 60s southeast. Friday`s highs will
range from the mid 40s to mid 50s. The NBM then suggests another
warmup through the weekend, but membership spread is also
rather large this far out. We will see breezy conditions almost
daily mid to late week.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 1018 PM CDT Sun Apr 13 2025
A low pressure system over central North Dakota this evening will
track southeastward into the overnight hours. Widespread
precipitation is expected to end from northwest to southeast through
tonight, but isolated to scattered rain or snow showers remain in
the forecast through Monday afternoon, primarily across central
North Dakota. MVFR to IFR ceilings will mostly prevail through the
evening, with gradual improvement to VFR anticipated from west to
east late tonight through Monday morning. Northwest winds around
10 to 20 kts with a few gusts to 30 kts will continue tonight
through Monday morning. Most areas will then see northwest
winds increase to 20 to 30 kts Monday afternoon, with gusts to
around 30 to 40 kts. The strongest winds Monday afternoon are
expected at KJMS and surrounding areas.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 1 AM CDT /midnight MDT/ Monday for
NDZ040>045.
&&
$$
UPDATE...Hollan
DISCUSSION...ZH
AVIATION...Hollan
Area Forecast Discussion
National Weather Service Dodge City KS
548 PM CDT Sun Apr 13 2025
.KEY MESSAGES...
- Widespread freezing temperatures increasingly likely (50%+
chance) Tuesday morning as center of cold high pressure moves
across Kansas
- Warming right back up later in the week with Thursday likely
seeing highs well into the 90s.
- Critical Fire Weather conditions increasingly likely as well
on Thursday afternoon.
- Cooler, wetter pattern emerging for next weekend with numerous
models and ensemble system members showing well in excess of
one-half inch of rain across portions of our region, however
details are highly uncertain this far out.
&&
.DISCUSSION...
Issued at 352 PM CDT Sun Apr 13 2025
This afternoon`s water vapor imagery and objective analysis fields
from the RAP model show a low-amplitude shortwave trough moving east
across the Dakotas. There was also a southern stream jet axis
extending from well down into the subtropics, west of Baja
California, extending northeast into the central CONUS, which
yielded an abundance of high cloud cover. A cold front pushed south
across southwestern Kansas earlier this morning, but the cooler
temperatures were still well to the north of the front itself as
afternoon temperatures pushed well into the 80s south of the
Arkansas River. A secondary surge of north wind and cooler air will
push across southwest Kansas later tonight with winds likely 20 to
30 mph at times, especially for the few hours when MSLP tendency
is greatest (5-7mb/3hr). The continued cold air advection will
allow surface temps to bottom out well down into the 40s for
lows with even some upper 30s possible across far west central
Kansas.
The north-northwest winds will continue through the day Monday with
the core of the cooler air mass across western Kansas. This will
result in afternoon temperatures 15 to 20 degrees cooler than this
afternoon (mid 60s for highs). Tuesday morning will be the coldest
morning as the center of the surface high will be positioned over
southwest Kansas right at daybreak. Ideal radiational cooling
conditions will result in widespread lows in the lower 30s. Latest
NBM shows probability of 32F or less temperatures in the 50-70%
range northwest of a Ulysses to Garden City to Hays line.
As we head deeper into the workweek, we will be reverting right back
to a very warm pattern as southwest downslope winds redevelop ahead
of a pattern change toward lowering heights across the Southwest.
The southerly winds will draw up some low level gulf moisture,
however much of the initial moisture advection mid-week will mainly
be east of southwest Kansas. We will see some showers and isolated
thunderstorms develop across mainly the eastern half of Kansas late
Wednesday Night/early Thusday morning. On Thursday, very warm and
very dry downslope west-southwesterly winds will likely yield
Critical Fire Weather conditions as all global models are showing a
similar MSLP pattern of a 996mb or deeper surface low across far
northwest Kansas or northeastern Colorado on Thursday afternoon.
This will be followed by a rather formidable cold front late
Thursday Night into Friday. After a day of highs well into the lower
to perhaps mid 90s on Thursday, temperatures Friday will likely be
some 20 degrees cooler, if not more, given the strength of the cold
air advection. We will probably see a downtrend of the forecast
highs for Friday, perhaps down to the current 25th percentile
numbers of lower to mid 60s. In fact, all three days Friday through
Sunday will present a very difficult temperature forecast,
especially considering the growing possibility of a wet storm system
with a low track favorable for widespread precipitation across our
region late in the upcoming weekend. Keep checking back for updates
concerning next weekend given all the uncertainty in both
temperatures and rainfall chances/amounts.
&&
.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1234 PM CDT Sun Apr 13 2025
Winds will remains sustained above 12 knots through the entire
overnight and begin gusting around 20-24 knots after about 4z
this evening. No restrictions are anticipated as the clouds
coming in after midnight will be above about 10k ft.
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...Umscheid
AVIATION...Russell
Area Forecast Discussion
National Weather Service Sioux Falls SD
1031 PM CDT Sun Apr 13 2025
.KEY MESSAGES...
- Critical fire danger will continue into the evening in areas
along and west of I-29.
- Winds will increase through the evening hours with potential
for winds to peak near advisory levels for a couple hours
overnight over the entire forecast area. Strongest sustained
winds expected west of I-29.
- Colder with scattered rain showers Monday afternoon. Would
not rule out isolated lightning/tiny hail. Very low (<20%)
potential for snow to mix with rain in the highest elevations.
- Winds may again approach advisory levels Monday afternoon,
and convective showers have potential to bring down pockets of
50+ mph winds. Additional wind advisories may be needed.
- Increased rain chances (30-50%) are seen by Thursday-Thursday
night. However, uncertainty in timing prevents greater details
at this time. VERY conditional severe weather risk along and
south of Highway 20.
&&
.DISCUSSION...
Issued at 224 PM CDT Sun Apr 13 2025
THIS AFTERNOON: Surface trough gradually sliding east this
afternoon, pushing surface winds to the west northwest in most
areas. Winds will begin gusting up to advisory levels in central SD
this afternoon and with mixing deepening, we`ll begin to finally
pull drier air downward. Fire danger remains critical west of I-29
into the evening. Please see separate fire weather discussion for
details.
TONIGHT: Stronger low-lvl cold advection begins to arrive this
evening, bringing a reinforcing push of stronger winds from west to
east across the CWA. While the combination of higher sustained and
gusts remains along and west of the James River, there will be
potential for an hour or two of near advisory gusts further east
into portions of Minnesota and Iowa overnight. At this time, given
the brevity of the gusts, will hold off on pushing the advisory
east, but will need to monitor this evening.
MONDAY: A very progressive upper trough swings southeast through the
Dakotas on Monday. While winds will subside slightly at sunrise, an
increasing SPG will keep sustained winds under advisory levels
through the morning. The initial surge of dPVA associated with
the trough may lead to a linear band of light rain developing
over eastern SODAK with this band of rain shifting into the
Buffalo Ridge by mid-day. Meanwhile behind the passage of the
initial surge of vorticity, surface lapse rates will sharpen
quickly as low lvl cold advection intensifies. Warming afternoon
temperatures should lead to the rapid development of convective
showers through the afternoon moving NW to SE. Soundings
suggest upwards of 100-300 J/KG MLCAPE (potentially up to 500
J/KG from RAP soundings), so anticipating some lightning, and
wouldn`t be surprised to see small hail. At times, if freezing
levels fall low enough, a few clusters of snow may be possible
late in the day. The deepening lapse rates will also promote an
increased potential to see strong wind gusts through the
afternoon near advisory levels. It`s not impossible, based on
convective model simulations, to see isolated gusts over 50 to
55 mph as showers move through. A wind advisory could certainly
be issued by later shifts, though if we instead see a deepening
strato- cu layer then widespread strong gust potential could be
subdued.
MONDAY NIGHT: The upper trough moves east overnight, allowing skies
to clear into Tuesday. Temperatures through may be quite cool,
with lows falling into the upper 20s to lower 30s.
TUESDAY-WEDNESDAY: Ridging moves into the Plains by Tuesday,
signaling a return of warm advection and also warmer temperatures.
We`ll likely see a return of temperatures into the upper 50s
and 60s. Mid-lvl clouds may be on the increase by Wednesday as a
subtle weakness moves through the mid-lvl flow. The presence of
this cloud layer likely won`t impact temperatures, with highs
by Wednesday afternoon rising into the 70s over much of the
area.
THURSDAY-FRIDAY: Troughing will increase over the western CONUS by
the middle of the week, allowing flow through the Central and
Northern Plains to turn southwesterly. Most medium range
guidance continues to indicate moisture transport from the Gulf
northwest into the Oklahoma Panhandle and then shifting further
north into the Plains on a 50 knot LLJ by Thursday morning. As
an embedded shortwave in the southwesterly flow arrive, elevated
convection is likely to develop at times late Wednesday night
into Thursday morning, potentially continuing through the day
north of a stalled warm front. AI based guidance continues to
hint at the potential for stronger storms into eastern Nebraska
and portions of western/northwestern Iowa in the afternoon and
evening hours of Thursday south of this aforementioned boundary,
though there the degree of capping remains problematic. Colder
air sinks into the region for Friday with temperatures falling
back into the 50s and 60s with considerable clouds.
SATURDAY-SUNDAY: Medium range guidance has settled into a solution
that will keep the majority of next weekend dry. However we`ll keep
an eye on an upper low tracking into the Plains from the Four
Corners region. This system has the potential to spread widespread
rain into the area to start next week. In fact, NBM/LREF
probabilities for >0.10" are already over 50% for most of the
area.
&&
.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1030 PM CDT Sun Apr 13 2025
VFR conditions begin the TAF period. Gusty northwest winds persist
across the area with gusts as high as about 35 knots. These winds
will slowly weaken through the night. At the same time, MVFR stratus
will push into the area tonight as well. The MVFR ceilings will
continue through the morning hours tomorrow before lifting back to
VFR levels during the afternoon hours. This is the same period of
time that scattered showers will overspread the area. At this time,
have only added PROB30 groups to all TAFs given the scattered nature
of the showers. There could be an isolated lightning strike in the
showers but confidence is too low to include mention of thunder in a
TAF at this time. Northwest winds will restrengthen for the
afternoon hours with gusts again up to 30-40 knots. Should see winds
begin to wane and the scattered showers dissipate during the evening
hours to end the TAF period.
&&
.FIRE WEATHER...
Issued at 224 PM CDT Sun Apr 13 2025
Lower dewpoints a bit slower to advect east and mix down this
afternoon, delaying the lowest relative humidity values slightly.
That said, with winds remaining well above red flag criteria into
the evening, see no reason to modify current red flag warning as
relative humidity value bottom out this evening.
A slightly more uncertain fire weather forecast is in place for
Monday. Strong sustained winds between 20 and 30 mph with
occasional gusts up to 45 mph may be again possible Monday and
Monday afternoon. More uncertain however is what will happen
with dew points in the afternoon, especially along the Missouri
River. Currently projected relative humidity values bottom at 25
to 30%, with potential for gusts in the afternoon around 40 to
45 mph. Additionally, the development of scattered to numerous
showers in the afternoon may limit fire danger slightly, though
lightning could provide fire starts. Do not feel confident
enough to issue a red flag warning at this time, but will issue
a fire weather watch to advertise the potential along the edge
of critical levels.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Fire Weather Watch from Monday afternoon through Monday
evening for SDZ050-063-068>071.
Wind Advisory until 4 AM CDT Monday for SDZ038-050-052-053-
057>060-063>065-068.
MN...None.
IA...Fire Weather Watch from Monday afternoon through Monday
evening for IAZ031.
NE...Fire Weather Watch from Monday afternoon through Monday
evening for NEZ013-014.
&&
$$
DISCUSSION...Dux
AVIATION...Meyers
FIRE WEATHER...Dux
Area Forecast Discussion
National Weather Service Grand Rapids MI
1004 PM EDT Sun Apr 13 2025
.KEY MESSAGES...
- Chance of precip thru Tuesday morning
- Storms on Friday?
&&
.UPDATE...
Issued at 1003 PM EDT Sun Apr 13 2025
The ongoing showers and thunderstorms are anchored along the
pressure gradient which has caused gusty winds to develop over the
open waters of Lake Michigan. These gusty winds could occur and
the area of rain moves onshore with gusts around 40 mph. Showers
will gradually exit east after midnight.
&&
.DISCUSSION...
Issued at 353 PM EDT Sun Apr 13 2025
- Chance of precip thru Tuesday morning
HRRR shows potential for bands of warm advection precip continuing
overnight. We had mostly trace to couple hundredths precip this
morning but deeper moisture and continued WAA/isentropic ascent
should result in perhaps a couple tenths QPF across the northern
zones where lift is strongest.
The low center passes north of the forecast area on Monday with
the cold front arriving on the afternoon, Winds could gust 35 to
40 mph in the afternoon and evening as cold air advection gets
going. Colder air on the backside of the low in cyclonic flow will
bring a mix of rain and snow showers Tuesday morning before
subsidence and drying arrives in the afternoon.
- Storms on Friday?
We will continue to monitor the path of the low at the end of the
week. Last couple runs of the ECMWF shows Lower Michigan on the
cool side of the slow-moving or stalled front while GFS shows
some potential for severe weather in a warm sector with a strong
shear environment.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 850 PM EDT Sun Apr 13 2025
VFR continues to dominate the weather pattern through the first
half of the overnight period. Showers continue to stream into
Michigan north of the TAF sites. LLWS is expected to move overhead
with LLWS between 1500 to 2KFT at 40 to 45 kts. That LLWS will
continue until around 06Z at the latest. At which showers and
drizzle will move overhead bringing MVFR to IFR cigs and vsbys.
There is still some question as to how low cigs and vsbys will
drop. There is the potential for IFR to LIFR between 09Z to 16Z.
Have continued the IFR accordingly.
Conditions will improve late morning with winds mixing down early
afternoon.
&&
.MARINE...
Issued at 1003 PM EDT Sun Apr 13 2025
Showers north of Grand Haven are producing gales and will continue
before subsiding by midnight. A cold front will move through
Monday bringing another round of gusty west to northwest winds and
building waves. A Small Craft Advisory is in effect for Monday
afternoon into Tuesday morning. Another cold front moves through
Monday night allowing for deeper mixing into Tuesday tapping into
stronger winds aloft. A Gale Warning may be needed for Tuesday
morning and afternoon, if not the Small Craft Advisory will need
to be extended into Wednesday.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory from 2 PM Monday to 6 AM EDT Tuesday for
LMZ844>849.
&&
$$
UPDATE...
DISCUSSION...Ostuno
AVIATION...RAH
MARINE...Ostuno/RAH
Area Forecast Discussion
National Weather Service Indianapolis IN
1153 PM EDT Sun Apr 13 2025
.KEY MESSAGES...
- Major flooding continues on the lower White River
- Significant river flooding continuing through at least the next 1
to 2 weeks in some spots on the lower White and lower Wabash
- Potential for thunderstorms Monday afternoon, a few cells in
the far SE may have stronger winds mix down
- Warming trend towards the end of the week
&&
.FORECAST UPDATE...
Issued at 930 PM EDT Sun Apr 13 2025
Clouds are expanding back into the region this evening ahead of a
warm front near the Mississippi River. Wind gusts had dropped off
for the moment but are expected to resume by late evening as the
pressure gradient tightens in advance of low pressure over Iowa. 01Z
temperatures largely ranged from the mid 50s to the lower 60s.
The overnight forecast is in good shape. Cloud coverage will
increase into the first part of the overnight prior to the warm
front moving through the region. Winds will veer to southwest in the
predawn hours in advance of the trailing cold front which will be
moving into the northern Wabash Valley shortly after daybreak.
Temperatures will be kept up by the clouds...winds and warm
advection...remaining in the 50s.
Zone and grid updates out.
&&
.SHORT TERM (This evening through Monday)...
Issued at 301 PM EDT Sun Apr 13 2025
Breezy southerly winds this afternoon will continue overnight. Can`t
rule out a few showers popping up this afternoon as passing clouds
move through.
A front will be moving through the region tomorrow. Ample WAA will
help to warm temperatures to the upper 60s to potentially low 70s
tomorrow by late morning ahead of the front. Temps will then remain
steady through the afternoon as the front slowly moves through and
finally start to cool off as normal in the evening after the front
passes, but with winds more westerly temps won`t drop off quite as
quickly as they do behind more prominent cold fronts. Showers and a
few thunderstorms may form along the front as well but models vary
on when and where precipitation will form. The global and regional
models are quicker for the precip to form, showing it will do so
over central Indiana during the day Monday. CAMs however are more so
indicating that showers will form either in our far SE or further
south later in the day. Thus confidence is low, especially as there
really won`t be much moisture to work with and while the front will
provide lift, it looks to be a broad enough front to limit it`s
power. There is a conditional threat for severe weather should
showers and storms form over the area. The best chance for strong to
severe storms will be over the SE, with strong winds the main threat
but hail can`t be ruled out.
&&
.LONG TERM (Monday night through Sunday)...
Issued at 301 PM EDT Sun Apr 13 2025
Monday`s cold front will be well east of Indiana at the start of the
long range. Persistent upper-level troughing over the East Coast
will maintain northwesterly flow and cooler temperatures through
about midweek. A gradual pattern shift is shown in ensemble
guidance, with increasingly prominent troughing setting up over the
Rocky Mountains. Simultaneously, troughing over the East Coast is
replaced by ridging. Such a pattern shift should bring about a
warming trend along with a potentially more active weather pattern.
In terms of impactful weather, the long range seems fairly quiet to
start. A tight MSLP gradient behind Monday`s front will lead to some
gusty northwest winds on Tuesday. Gusts may be a high as 35 to 40
mph. Those winds die down as surface high pressure arrives on
Wednesday. Increasing winds, this time from the south, look to
develop late Thursday or on Friday as the first upper-level impulse
ejects from the developing west coast trough. With flow turning
southerly, warmer temperatures are likely by week`s end.
Precipitation potential looks low until Thursday or Friday when the
aforementioned wave ejects from the Rockies. Strong southerly flow
ahead of it will bring rich moisture northward along with the warmer
air. A few rounds of rain are possible: first, showers and elevated
thunderstorms with the system`s warm front on Thursday night.
Second, showers and thunderstorms associated with the cold front
dropping southward the next day. Guidance shows sufficient wind
shear for organized convection, so severe potential will need to be
monitored closely in the coming days.
Uncertainty in the forecast comes from some model disagreement
regarding the upper-level evolution late in the week. While all
models show troughing developing out west, they show it becoming
partly cut off from the main jet stream further north. Guidance can
have trouble with cut off lows and some of these difficulties can be
seen with this one already. Trends in guidance have been slowing the
trough down, which is not unexpected as models tend to eject these
features too quickly. This in turn leads to uncertainty on exact
position, which can lead to timing differences on potential vort
maxes ejecting from the parent trough. These, in turn, can end up
playing a critical role on convective evolution further downstream.
&&
.AVIATION (06Z TAF Issuance)...
Issued at 1152 PM EDT Sun Apr 13 2025
Impacts:
- VFR Conditions expected this TAF period
- Westerly Wind gusts possible Monday afternoon
Discussion:
GOES16 shows extensive mid-level cloud cover across Indiana,
resulting in VFR ceilings. Regional radar show no precipitation
across the area as lower levels remained very dry. Dew point
depressions across the area were around 20F. Surface analysis shows
low pressure in place over western IL/Eastern IL with a trailing dry
cold front stretching SW into central MO.
Models show the low and the associated moderate pressure gradient
pushing across the Taf sites through this period. Forecast soundings
and time heights continue to keep lower levels dry, and HRRR only
develops some convection with the cold front well SE of the TAF
sites late on Monday. Thus a dry forecast with VFR conditions will
continue, with winds shifting to the west after 13Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Ryan
SHORT TERM...KF
LONG TERM...Eckhoff
AVIATION...Puma
Area Forecast Discussion
National Weather Service Marquette MI
1151 PM EDT Sun Apr 13 2025
.KEY MESSAGES...
- Rain shower coverage increases this evening into Monday
morning with a few embedded thunderstorms possible.
- Rain changes over to snow late Monday into Tuesday. Accumulating
wet snow and high winds will lead to travel impacts for the Tuesday
AM commute. Winter Weather Advisories are in effect.
- Wind gusts to or above 45 mph are possible over the Keweenaw and
eastern U.P. Monday night to Tuesday morning. Blowing snow in these
areas could significantly reduce visibilities in spots.
- Northwest gales of 35 to 45 knots are expected over much of Lake
Superior Monday and Tuesday.
- RHs will fall into the 20-30% range Wednesday, but fire weather
concerns mitigated by light winds and prior precipitation.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 303 PM EDT Sun Apr 13 2025
Afternoon satellite and RAP analysis reveal a broad mid-level trough
across the north-central CONUS with a few embedded waves nosing into
the upper Midwest. At the surface, a ~998 sfc low pressure is
beginning to take shape in far SW Iowa/NW Missouri. Isentropic
ascent ahead of the northern Plains shortwave has kicked off some
light showers across the UP this afternoon. Gusty southerly flow has
enabled temperatures to soar into the 50s area wide, with a few low
60s across the interior west.
Through the evening and into Monday morning, the developing sfc low
to the south continues its northward trek, phasing with the
weakening sfc feature in the northern Plains right over western Lake
Superior by daybreak. As this occurs, another round of showers is
expected this evening. This second round is currently developing
across far northern WI into the western UP, as seen by the uptick in
nearby radar reflectivity and agitated cu via Day Cloud Phase
Satellite. RAP analysis paints meager elevated MUCAPE between 100-
300j/kg across this region, which should nose into the area this
evening, thus cannot rule out an embedded thunderstorm overnight.
Rainfall amounts will vary depending on any heavier embedded showers
overnight. Though we are not anticipating any widespread flooding
impacts, its worth noting the potential rise in local streams and
rivers with rain on top of a melting snowpack. As the sfc low
reaches western Lake Superior by morning, the system`s dry slot will
work to diminish ongoing precip across the south-central.
&&
.LONG TERM /MONDAY THROUGH SUNDAY/...
Issued at 404 PM EDT Sun Apr 13 2025
By 12Z Monday, a pair of shortwaves will be traversing the Upper
Midwest, set to phase into one negatively tilted trough as it passes
north of Lake Ontario by Tuesday afternoon. Strengthening cool
meridional flow behind the system will allow for lake-enhanced to
lake-effect snowfall impacting the Tuesday morning commute. Ridging
aloft then brings quiet weather to the midweek before chances for
disturbed weather return to the forecast leading into the weekend,
though spread in the details is high at this time.
Moving into Monday, rain is expected to still be falling over the
eastern end of the UP and along Lake Superior. The 12Z HREF shows
pretty stark dry-slotting cutting into precip potential over the
interior west and south-central UP. While precip ramps back up for
the interior west on the back end of the system, Menominee County is
only around 15% likely to see precipitation beyond Monday afternoon.
While 6-hourly rain rates of over 0.1"/6hr in the western UP will
lead to some river rises especially in locations such as the
southern end of the Keweenaw Peninsula with a ripe snowpack to melt
(between 18 inches deep in Herman and 31 inches deep in Painesdale),
the bigger impacts from this system will be the lake-enhanced to
lake-effect snow on the back end Monday PM into Tuesday. With
surface temperatures cooling to sub-freezing through Monday night,
precipitation will change from rain to a wet snow, boosted by 850 mb
temperatures falling to around -8 C over a Lake Superior that is
around 2-3 C. Euro ensemble Snow EFI is around 0.5 for this system
but the shift-of-tails is low, meaning that impactful conditions are
expected (a "high floor"), but extreme solutions are not (a "low
ceiling"). Chances for at least 4 inches of snowfall are high enough
to warrant Winter Weather Advisories with this package, though
chances of at least 8 inches (worthy of a Winter Storm Warning) are
below 60% UP-wide and especially given the questions surrounding
temperatures impacting precip type and snow ratios, will stick to
advisories for now and generally not expect any Winter Storm
conditions except for perhaps in the immediate vicinity of Mount
Arvon. Chances and coverage of snowfall then gradually wane from
west to east Tuesday as synoptic support fades and temperatures
aloft become not supportive for pure lake effect snow.
One other hazard to consider with this system will be the gusty
winds. The cold advection in the cold sector of the system in
addition to rapid pressure falls/rises as the low tracks over Lake
Superior (up to 9 mb/6 hr by Tuesday 00Z) will lead to some gusty
conditions. Euro ensemble mean gusts are over 40 mph over the
central UP by 18Z Monday, though the HREF is closer to 35 mph. Euro
ensemble probabilities of 40mph are widespread 70-90% by 00Z Tuesday
and above 90% for the east half by 18Z Tuesday. On the other hand,
HREF probabilities of 40 mph gusts are only around 50%. Given the
spread in model guidance for the gusty wind conditions, will elect
to punt Wind Advisory headline decisions a bit later, but messaging
the wind gusts in the winter headlines is a priority.
A quiet Wednesday is then expected as ridging aloft pushes over the
region bringing high pressure over the region. Looking upstream, a
shortwave crossing the Rockies from the northwest will begin to brew
another lee surface low, but spread in the global deterministic
guidance as well as intra-ensemble spread is still fairly high for
this time range, resulting in surface lows passing through the Upper
Great Lakes anywhere from late Thursday night to early Saturday.
This time of year, rain will be preferred, but there is enough
spread in the temperature guidance to support at least some snow
chances mixing in at times, though impactful snowfall is not
expected at this time and chances of accumulating freezing rain is
20% or less through the 22nd. Another high pressure in the region
should give fairer weather to end the weekend. When precipitation is
not expected to occur, some attention to the fire weather forecast
should be taken as the NBM (which is notorious for not catching
events of RH dropping out in fair weather in the spring in the UP)
is already calling for RHs to fall to near 30% Wednesday. In
response, have dropped RHs a little bit further on Wednesday into
the 20s% range, though the light winds and preceding precipitation
keep fire concerns tempered somewhat.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 1149 PM EDT Sun Apr 13 2025
VFR conditions continue at this time, but carried TEMPOs over the
next 4 hours to highlight a slow transition over to MVFR as a low
pressure system enters the Upper Great Lakes. By Mon 08Z, MVFR
should become the predominant flight category with further
deterioration to IFR/LIFR by Mon 10Z, especially at IWD and CMX.
Deterioration at SAW should be a tad slower and less likely. So,
will only carry a PROB30 for IFR at that site around Mon 10-12Z.
IFR/LIFR flight restrictions will persist through Monday afternoon
at CMX, but IWD and SAW could see some improvement to MVFR by late
morning/early afternoon. Initial precip type with onset will be rain
with a few possible rumbles of thunder early this morning. It will
then transition to rain/snow and all snow by this afternoon at IWD
and CMX followed by SAW early tonight. Meanwhile, southerly winds
will shift to the west/northwest through the morning, becoming
strong with sustained speeds of 15-20 kts, gusting to 35 kts.
&&
.MARINE...
Issued at 404 PM EDT Sun Apr 13 2025
As low pressure cuts through the western half of Lake Superior
tonight, southeast winds gust to 25 knots over the east half through
tonight. As winds become westerly and then northwest across the
entire lake Monday, wind gusts ramp up to gales to 40 knots by the
evening hours and the north-central and east-central portions of the
lake are expected to reach up to 45 knots. Chances of storm force
gusts to 50 kt remain 20% or less. Gales fall off in the west half
Tuesday morning, though gales hang on through the day Tuesday in the
east, falling sub-gale by midnight. Long-duration intense northwest
will allow for waves to build especially over the east half of the
lake, peaking at 12-17 ft early Tuesday morning, highest along
the Pictured Rocks National Lakeshore. Under high pressure,
winds fall below 20 kt in the west half of the lake early
Wednesday morning and in the east by the mid-afternoon. Waves
fall below 4 feet lakewide by Wednesday night. Attention then
turns upstream, where another low is expected to pass through
the Upper Great Lakes, but uncertainty still remains in the
timing and intensity of such a system.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Winter Weather Advisory from 8 PM EDT /7 PM CDT/ Monday to 11
AM EDT /10 AM CDT/ Tuesday for MIZ001>003-009-084.
Winter Weather Advisory from 8 PM Monday to 2 PM EDT Tuesday
for MIZ004-005.
Lakeshore Flood Advisory from 2 AM to 11 PM EDT Tuesday for
MIZ006-007.
Winter Weather Advisory from 2 AM to 8 PM EDT Tuesday for
MIZ006-007-085.
Lake Superior...
Gale Warning from 2 PM EDT /1 PM CDT/ Monday to 8 AM EDT /7 AM
CDT/ Tuesday for LSZ162.
Gale Warning from noon EDT /11 AM CDT/ Monday to 10 AM EDT /9
AM CDT/ Tuesday for LSZ241-242-263.
Gale Warning from 2 PM Monday to 1 PM EDT Tuesday for LSZ243-
244-264.
Gale Warning from 5 PM Monday to 1 PM EDT Tuesday for LSZ245-
248-265.
Gale Warning from 4 PM Monday to 7 PM EDT Tuesday for LSZ249-
250-266.
Gale Warning from 9 PM Monday to 7 PM EDT Tuesday for LSZ251-
267.
Lake Michigan...
Gale Warning from 11 AM to 8 PM EDT Monday for LMZ221-248-250.
&&
$$
SHORT TERM...BW
LONG TERM...GS
AVIATION...TDUD
MARINE...GS
Area Forecast Discussion
National Weather Service Nashville TN
628 PM CDT Sun Apr 13 2025
...New AVIATION...
.KEY MESSAGES...
Updated at 621 PM CDT Sun Apr 13 2025
- Next chance for rain is late tomorrow evening. Severe weather is
low for wind and hail.
&&
.UPDATE...
Issued at 608 PM CDT Sun Apr 13 2025
Ok, I`m sitting here going through the latest CAMs for tomorrow
and I`ve got one eyebrow raised now. The 18Z HRRR came in strong.
1000+ J/Kg of sfc CAPE north of I-40 as the front enters the mid-
state late tomorrow afternoon. That`s an outlier. Maybe double
what any other member of the HREF is showing at the same time.
However, the soundings. If we can realize even half of what
instability the HRRR is suggesting, soundings are almost similar
to what we saw Thursday when we got all those wind and hail
reports. So, I`m not sounding the alarm, by any means, but those
along and north of I-40 should remain weather aware from 4 until
about 10 pm tomorrow. I would say that the chance for severe
weather isn`t zero, but it`s low for wind and hail. Tornado
chances are even lower than low as the hodographs remain
elongated. I`ll take a look at the 00Z CAMs here in a couple of
hours and we`ll see if there`s any consistency regarding a severe
potential. There could be a very small window before CAPEs quickly
fall off for the evening after sunset.
&&
.SHORT TERM...
(Rest of today through Monday Night)
Issued at 1113 AM CDT Sun Apr 13 2025
It`s a beautiful day in the neighborhood, with sunny skies and
temperatures in the 60s and 70s for highs. Not much to add to that
until we get into Monday evening. Our next chance for precipitation
is Monday evening into Tuesday, but it continues to look paltry in
guidance. Moisture advection seems to be really struggling, with
dewpoints stuck in the mid 50s in most models currently. QPF still
is very inconsistent in the guidance, but closing in on a tenth of
an inch being the most reasonable maxima for our area. Looking at
forecast soundings, some thunder could be possible Monday night into
Tuesday morning, but I`m just not impressed with this setup for
possible severe weather. The lower levels are dry, low level lapse
rates are very slow, just overall not supportive.
&&
.LONG TERM...
(Tuesday through next Sunday)
Issued at 1113 AM CDT Sun Apr 13 2025
More beautiful days to come mid-week for middle Tennessee! Once the
front passes through Monday night, a ridge builds in and we get
quiet for a period of time. Highs will drop back into the 60s for
Wednesday, but then slowly rise back into the 80s after. The rain
chance I mentioned yesterday during the Thursday time frame has
moved significantly to the north, with possibly only a few sprinkles
on the KY border. Guidance is picking up on a weekend disturbance,
but is too inconsistent to give us a concrete idea of what could
occur other than the possibility of some rain. We will have to see
what solution becomes favored as we get closer temporally to say
anything more.
&&
.AVIATION...
(00Z TAFS)
Issued at 621 PM CDT Sun Apr 13 2025
VFR conditions persist this taf cycle. Gusty southerly winds will
continue through the overnight hours with sustained speeds between
10-12 kts and gusts up to 20 kts. Winds will shift SSW after 14Z
and sustained speeds will increase to near 15 kts with gusts to 25
kts.
A cold front will be moving through at the end of this taf period,
bringing lower cigs and rain/storm chances after 15/00Z. This
will be captured in the taf next forecast cycle.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 59 83 52 66 / 0 10 40 0
Clarksville 61 78 48 64 / 0 20 30 0
Crossville 52 78 48 59 / 0 10 60 0
Columbia 59 83 52 66 / 0 10 30 0
Cookeville 54 79 49 60 / 0 10 60 0
Jamestown 53 78 47 59 / 0 10 60 0
Lawrenceburg 58 82 53 65 / 0 0 20 0
Murfreesboro 58 83 52 66 / 0 10 40 0
Waverly 61 80 49 64 / 0 10 20 0
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE.......Unger
SHORT TERM...Holley
LONG TERM....Holley
AVIATION.....Baggett