Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/15/25
Area Forecast Discussion
National Weather Service Des Moines IA
801 PM CDT Mon Apr 14 2025
...Updated for the 00z Aviation Discussion...
.KEY MESSAGES...
- Wind gusts over 45 mph accompany showers and storms through 9pm
- Elevated fire weather conditions this afternoon and Tuesday as
breezy to windy conditions prevail much of the period
- Temperatures remaining above normal, warmest days Wednesday and
Thursday
- Storm chances Thursday afternoon and night with main risk being
large hail
&&
.DISCUSSION...
Issued at 254 PM CDT Mon Apr 14 2025
It has been another windy spring day across the state. Relative
humidity (RH) values have fallen into the 30% and even upper 20%
approaching critical levels at mid-afternoon. For now, have
highlighted the windy and elevated fire weather conditions this
afternoon and early evening in the Special Weather Statement
issued earlier this morning. Current satellite imagery shows
scattered cumulus across the state with more agitated and
clumped cumulus over much of South Dakota and southern North
Dakota this afternoon associated with the next shortwave trough
and PV anomaly. This is where there are showers with isolated
thunderstorms at mid- afternoon, which will spread southeastward
into Iowa yet this afternoon and evening. Main concern with
this activity is the subcloud dry air with surface dewpoint
depressions of 20 to 25 degrees. Latest HREF paintball
probability of 30 knots has a strong signal among its membership
for gusty winds with the showers/storms, though gusts peak
around 40 or so knots. There has been a steady signal in the
HRRR runs of 50 knot wind gusts accompanying these
showers/storms with other convective allowing models such as the
RAP, NamNest, and ARW cores showing gusts of 40 to 50 knots.
SPC introduced a marginal risk of severe weather with low wind
probabilities at midday and will be expanding at the mid-
afternoon update a bit farther southward. All of this gusty
shower and storm activity will diminish into this evening as the
shortwave departs the state, but the breezy winds from the
northwest will remain overnight tonight and persist into
Tuesday. Winds will be slightly less than today on Tuesday
sustained at 15 to around 20 mph with gusts of 25 to 35 mph
possible. The strongest winds will be over the eastern half to
two-thirds of the state, which will be displaced from the
lowest, critical RH values over the opposite portion of the
state. While short cool-season grasses along with burn breaks
have begun to green up primarily over southern Iowa, warm season
grasses remain dormant and fire practitioners in southwest Iowa
late last week reported "volatile" conditions. Therefore, at
least elevated fire weather conditions will exist given the
offset wind and near critical to critical RH values Tuesday
afternoon.
The flow over the region will transition from northwesterly Tuesday
to southwesterly by late in the week. This will result in higher
heights and temperatures as low level thermal lift develops. Highs
Wednesday into Thursday will be well into the 60s and 70s and may
touch 80 degrees in portions of the state Thursday afternoon. An
area of thunderstorms is likely to develop late Wednesday night
aided by the low level jet and low level thermal lift that will
continue into a portion of Thursday. Behind this wave Thursday
afternoon and early evening, higher instability may be able to
develop with impressive deep layer shear. While hodographs have good
turning in the low levels, forecast soundings show elevated warm
layer that will result in storms following more of a linear
hodograph. Thus, main concern at this point would be large hail with
the storms and will continue to assess if any other hazards may be
present as we near that time. As the cold front moves through on
Friday, may see storms develop along this boundary, though this may
be just over our southeastern forecast area or more so southeast
Iowa Friday afternoon or evening. This front will move into Missouri
and stall into this weekend. A shortwave at the base of a western US
longwave trough, which has facilitated our southwesterly flow the
latter part of this week, will move over or near Iowa late in the
weekend. This would allow for the boundary to move back into the
state and should see renewed shower and storm chances late in the
weekend or early next week.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 627 PM CDT Mon Apr 14 2025
Main impact to aviation will be light showers moving through dry
air producing strong wind gusts over the area. Minimal
precipitation is expected, but gusts over 40 kts are possible
as they move through. Lightning/thunder has been extremely
isolated, so have removed this from most terminals and will
update if it appears more imminent than it has been. Showers
diminish overnight, but sites still remain breezy through
tomorrow. Otherwise, expect VFR ceilings and visibility to
persist through the period.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...Ansorge
AVIATION...Dodson
Area Forecast Discussion
National Weather Service Louisville KY
958 PM EDT Mon Apr 14 2025
.KEY MESSAGES...
* Cool and sunny conditions arrive for the middle of the week before
warmer temperatures return for the weekend along with more rain
chances.
&&
.UPDATE...
Issued at 957 PM EDT Mon Apr 14 2025
Instability is decreasing, showers in the area are struggling, and
the latest HRRR shows just some weak convection over the next few
hours, so after coordinating with SPC, have gone ahead and dropped
the rest of SVA 138 in central Kentucky.
Issued at 721 PM EDT Mon Apr 14 2025
At 23Z a cold front, depicted by a sharp drop in dew points and a
subtle shift in winds from west to west northwest, was draped across
central Kentucky from Morgantown to Elizabethtown to Frankfort. This
boundary will continue to push to the southeast this evening.
Convergence along the front is very weak and mid-level warmth has
kept convection is check so far this evening. However, there remains
good buoyancy in the warm air mass ahead of the boundary with SBCAPE
of 1000-1500 J/kg, along with strong deep layer shear around 60kt. A
small 5H speed max will be crossing southern Indiana over the next
few hours. Thus, it seems that we are not entirely out of the woods
yet regarding the possibility of more energetic cells. Indeed, since
about 2230Z new cells have begun to blossom over the southern
Bluegrass between Lexington and Lake Cumberland. DCAPEs are weak but
WBZ heights are around 10k`, suggesting hail may be the primary
threat with winds secondary. Earlier storms in the upper Ohio Valley
produced many more hail reports than wind.
Given the above, especially the fact that new storms are finally
starting to pop, which is in general agreement with the timing CAMs
were showing in earlier runs, will hold on to the Severe
Thunderstorm Watch ahead of the front for now.
&&
.SHORT TERM /THROUGH TUESDAY/...
Issued at 346 PM EDT Mon Apr 14 2025
A sfc cold front extends southwest through southern IN early this
afternoon, with a notable wind shift and low-level theta-e gradient
from our southern IN counties northward. South of the boundary, sfc
temperatures have warmed into the mid 70s to near 80 degrees with
sfc dewpoints in the lower 60s. As of 2 PM EDT, convective
initiation has taken place in Washington, Scott, and Jefferson
counties in Indiana. This is the first sign of convection able to
punch above a warm capping layer near 700 mb, as seen on recent SDF
ACARS soundings. It appears this activity will lift ENE toward
northern KY and SW Ohio with additional development along its
eastern flank. Further south, much of the rest of our forecast area
will remain dry until mid to late afternoon.
This afternoon and evening, a potent upper level trough currently
over the Northern Plains will rotate southeast toward the Mid-MS
Valley. Gradually strengthening mid and upper level WSW flow will
gradually overspread the destabilizing warm sector in central and
eastern KY. The sfc cold front will slowly sink southeast through
central KY through late this evening. We`ll also continue to see
gradual low-level moisture advection from the SW ahead of the
boundary. A broken line of showers and thunderstorms is still
expected to take shape between 20-22Z over central KY. The highest
severe threat is still expected to be east of I-65, where MLCAPE
should reach 1000-1500 J/kg by 20-22Z. In addition to the
increasingly warm, moist near-sfc layer, lapse rates exceeding 7-7.5
C/km are noted above the 700 mb capping inversion. Effective bulk
shear is robust at 50-60 kt, and the wind profile produces a long
straight hodograph with deep W/WSW flow.
Given the instability and deep-layer shear in place, some storms
will likely become strong to severe with a threat for isolated
damaging winds and large hail. The tornado threat appears lower,
limited by weak low-level SRH and relatively high LCLs. HREF
Significant Tornado Parameter does briefly increase to 1-2 along and
southeast of a Hodgenville to Frankfort line. So the highest tornado
risk (still relatively low) is over the Bluegrass Region.
Beyond 22-23Z, the broken line is expected to sink into south-
central KY. Updraft strength should wane during the 00-02Z time
frame with waning instability. Showers could linger in southern
KY/Lake Cumberland region through around Midnight or so, with mainly
dry conditions early Tue morning.
Clouds should gradually clear from NW to SE early Tue morning, with
CAA and breezy WNW flow in the wake of the front. Lows Tuesday
morning will range from the mid 40s to around 50 degrees. Cool NW
flow continues through Tuesday, with the upper level trough axis
swinging through during the first half of the day. Expect an
increase in cloud cover over southern IN and north-central KY during
the midday hours as additional moisture rotates through. Afternoon
highs will range from the mid 50s in the Bluegrass and southeastern
IN to the lower 60s in southern KY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Issued at 346 PM EDT Mon Apr 14 2025
Tuesday night, upper ridging and surface high pressure begin pushing
east into the Lower Ohio Valley. This will cause skies to clear. At
first while the region is east of the surface high, CAA will limit
highs on Wednesday to the upper 50s to mid 60s, but as the high
passes east of the area Wednesday night, WAA will lift highs to the
mid 60s to low 70s on Thursday and into the mid 70s to low 80s by
Friday as southwest winds gust to 30 mph ahead of an approaching
cold front.
Late Friday night into early Saturday morning, a cold front oriented
west-southwest to east-northeast will approach the Ohio River from
the northwest, resulting in increased precipitation chances over
southern Indiana and central Kentucky. Believe the best chances will
be near the Ohio River with little to no rain in far southern
Kentucky. The front will remain fairly stationary until Sunday
evening, keeping precipitation chances in place during this time.
Peak precipitable water values along the front are expected to reach
around 1.5". Highs rainfall amounts look to range from 0.5 to 1"
across southern Indiana and north central Kentucky with lower
amounts to the south, around 0.25" in Bowling Green. Thunder will be
possible at times, but severe weather doesn`t look like much of a
concern.
Monday, the next cold front will move through the CWA. This one will
extend from a low pressure system sliding northeast through the
Midwest, and with the latest model runs, model agreement in timing
is pretty good with the GFS and Euro. They both have the northeast
to southwest oriented front coming through early Monday morning.
With the timing early in the day, model soundings show very little
instability, and shear is also marginal. This could produce some
thunder, but doesn`t currently look severe.
&&
.AVIATION /18Z TAFS THROUGH 00Z THURSDAY/...
Issued at 639 PM EDT Mon Apr 14 2025
Main impact: Gusty winds
Confidence in gusty winds: High
A cold front passing through central Kentucky this evening may bring
scattered showers or an isolated thunderstorm to the LEX/RGA/BWG
airfields. Winds will continue to come in from the west.
On Tuesday a tight pressure gradient between low pressure over
Quebec and high pressure over Kansas and Oklahoma will result in
brisk west winds gusting to 20-30 knots at times. Stratocu are
expected to develop during the morning and last into the afternoon
but ceilings will remain VFR.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...None.
IN...None.
&&
$$
UPDATE...13
SHORT TERM...EBW
LONG TERM...KDW
AVIATION...13
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
640 PM CDT Mon Apr 14 2025
.KEY MESSAGES...
- Scattered showers this afternoon and evening, potentially
enhancing strong wind gusts across SW Minnesota.
- Warming back to above average by Weds/Thurs, ahead of another
surface low and rain chances.
&&
.DISCUSSION...
Issued at 326 PM CDT Mon Apr 14 2025
Tonight...Strong northwest winds continue this afternoon in the
wake of a deep cyclone exiting to our northeast. Expect
sustained speeds to remain around 20 to 30 mph and gusts up to
40 mph through the early evening. A broad area of scattered
showers and a few storms is tracking southeast into portions of
southwest Minnesota this afternoon. Given the already well-mixed
boundary layer, any stronger showers that are able to develop
could further enhance the gust potential. An extra 10 to 15 mph
on top of our already windy conditions would allow surface gusts
to approach or briefly exceed severe limits (58 mph). The
general consensus among the latest CAMS is for these to track
along and south of the MN river valley in SW and S Minnesota. At
the same time, more stratiform light rain will spread through
east-central Minnesota and western Wisconsin. As temperature
profiles cool down overnight, it is not out of the question for
some flakes to mix in, primarily over Wisconsin. Some hi-res
models, such as the 14.18z HRRR suggest some more narrow
corridors of locally enhanced snow showers could impact western
Wisconsin Tuesday morning.
Tuesday through Thursday...Clouds clear out from west to east,
making for a mostly sunny Tuesday with highs in the 50s. It`ll
remain breezy until the pressure gradient weakens by the
evening. Winds shift out of the south again, rising highs into
the 60s and 70s for Wednesday and Thursday. This will set the
stage for another surface low to bring showers and storms
across the region Thursday into Friday. The strength and extent
of any convection will largely be tied to LLJ Thursday evening.
Right now, southern Minnesota has the best shot to get in on any
action.
This Weekend...Temperatures will cool down back to around
normal to end the week, with ensembles continuing to hint at the
potential for another system to move through early next week.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 640 PM CDT Mon Apr 14 2025
Gusty northwest winds will persist tonight, though gusts will
decrease a little overnight. Diurnal showers from west central
to south central MN will diminish this evening, but more
persistent showers may last beyond 06Z from east central MN into
WI. Some MVFR in Wisconsin tonight is also indicated by short
term models, and current observations from central into northern
MN indicate this should continue extending into Wisconsin.
The MVFR ceilings will likely persist into late morning
Tuesday. Otherwise, gusts around 20-25 knots are expected into
mid afternoon Tuesday before the gradient begins weakening from
west to east.
KMSP...Steady light rain and some MVFR ceilings this evening just
north of the metro should slide east and southeast, but may
clip the airfield this evening with some MVFR ceilings and/or
visibilities. Otherwise, clouds should scatter out late tonight,
but am a little concerned some BKN040 may linger through the
night due to cyclonic low level flow that doesn`t really relax
until around 12Z. Doubt that it would be MVFR, however.
/OUTLOOK FOR KMSP/
WED...VFR. Wind SE 5-15kts.
THU...VFR, chc SHRA. TSRA/MVFR possible late. Wind SE 10-20kts.
FRI...MVFR, slgt chc SHRA. Wind NW 10-20kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&
$$
DISCUSSION...BED
AVIATION...TDK
Area Forecast Discussion
National Weather Service Marquette MI
1158 PM EDT Mon Apr 14 2025
.KEY MESSAGES...
- Winter Weather Advisories and Winter Storm Warnings are in effect
tonight into Tuesday as rain changes to wet snow, with snow
accumulations to near 8 inches in the high terrain of the western
UP, with accumulations of 2-6 inches for counties along Lake
Superior.
- Wind gusts to or above 45 mph are possible over the Keweenaw and
eastern U.P. tonight through Tuesday. Blowing snow in these areas
could locally reduce visibility and cause drifting over the roads.
Gales to 45 knots are expected over Lake Superior through Tuesday
night.
- Relative humidities will fall into the 20s% or lower range
Wednesday over the interior west and south central, but fire weather
concerns will be mitigated by light winds and prior precipitation.
&&
.SHORT TERM /THROUGH TUESDAY/...
Issued at 315 PM EDT Mon Apr 14 2025
Afternoon RAP analysis and GOES satellite imagery reveal a somewhat
vertically stacked 992 mb sfc low spinning just north of Lake
Superior. So far today, the system`s dry slot has kept much of the
UP dry save for some scattered rain showers. A tight pressure
gradient and modest mid to low level cold air advection has kicked
up winds across the area, where gusty westerlies between 35-45 mph
have already been realized. CMX has already managed a 54 mph gust!
Winds veer to the northwest this evening as the sfc low pulls to the
northeast. In response, have opted to extend the ongoing Wind
Advisory in Keweenaw and N Houghton counties through tomorrow
afternoon and introduce additional Wind Advisories eastward for
Marquette, Alger, Schoolcraft, and Luce counties through Tuesday
evening. Gusts 45-50 mph will be possible, especially along the
lakeshores, which combined with falling snow could significantly
reduce visibility and induce hazardous travel. Strong NW winds will
also create possible lakeshore flooding in Alger and Luce counties.
Speaking of falling snow, the main hazard this through the overnight
hours and into tomorrow morning will be heavy, wet snow. As cold air
continues to filter into the area on the cyclonic side of the
departing sfc low, deformation banding with a minor boost from lake
enhancement will begin to change rain showers to snow this evening
from west to east. Accumulating snow is expected across much of the
northern UP, specifically the high terrain areas of Marquette/Baraga
counties, the base of the Keweenaw, and Porcupine Mountain range. No
change has been made to the ongoing Winter Weather headlines. 6
hourly QPF amounts between 0.25-0.5" combined with wet SLRs 10:1 or
less will lead to total snow amounts between 5-10" for the
aforementioned high elevation areas, decreasing quickly nearer the
shorelines and across the south-central UP, where little to no snow
is expected at all. The latest 12z HREF guidance suggests increasing
probabilities (>75%) for 0.5-1" / hour snowfall rates across the
west half overnight, diminishing just after the morning commute.
Less confidence in snowfall totals exists across the east UP,
however, 3-6" of snow is still on the table east of Munising north
of M-28.
Bottom line: expect hazardous travel conditions to pick up tonight,
especially in the high terrain areas of the western U.P. and
lakeshores.
&&
.LONG TERM /TUESDAY THROUGH MONDAY/...
Issued at 408 PM EDT Mon Apr 14 2025
By 12Z Tuesday, an anomalously deep 500mb cutoff low will be north
of Georgian Bay (12Z GEFS 500mb height anomaly around -25 dam).
Strong cool meridional flow in the wake of this system will allow
for lake-enhanced to lake-effect snowfall and high winds 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 Tuesday, CAMs show a distinct lake-effect/upslope
signature which will end from west to east through the day as around
990mb low pressure south of James Bay is replaced by low-1020s mb
high pressure moving over the region by Wednesday afternoon. Before
the high pressure arrives though, cold advection and pressure rises
of up to 1mb/hr will lead to strong winds. The Euro ensemble mean
still suggests over 45 mph gusts over the eastern third of the UP,
though the HREF only suggests such gusts over the lakeshores over
the shores of the Great Lakes. Given some overperformance in the
gusts already so far today, will err on the side of stronger winds
and issue extensions to the current Wind Advisory for the Keweenaw
and issue new Wind Advisories for the eastern UP, and also Marquette
County given strong winds near the lakeshore. These winds will of
course be occurring during snowfall, though even the 75th percentile
of CAM guidance suggests PoPs falling below 30% for much of the west
coast of the UP by 14Z, so there is some potential for the Winter
Storm Warnings to be culled a bit sooner in real-time tonight into
tomorrow morning, but for this package, will elect to keep the
current headline levels and timing. The slushy nature of the
snowfall will make it challenging to blow and drift around, but
given the strength of the winds and cooler air aloft helping bring
snow ratios above 10:1, some visibility restrictions and travel
difficulties are still expected. The last of the snow showers should
end Tuesday night around 03Z, with snow totals in the east from 12Z
Tuesday onwards expected to be around 2-4 inches.
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
morning. This time of year, rain will be preferred and a few rumbles
of thunder cannot be ruled out, 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 6% or less through the
22nd. Another high pressure in the region should give fairer weather
to end the weekend, though early indications of yet another low
coming off the plains to kick off next week. 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 /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1157 PM EDT Mon Apr 14 2025
Rain has made the transition to snow early this morning at all TAF
sites as a low pressure system moves through Upper Michigan. The
system will move through rather quickly, though, with the heaviest
snow between Tue 06-12Z. Worst conditions remain concentrated at IWD
and CMX where IFR is prevailing with a period of LIFR likely from
Tue 09-12Z. Elsewhere, SAW should trend more toward MVFR with
possible IFR from sunrise through mid-morning. Look for a return to
VFR, though by mid to late afternoon. Meanwhile, strong northwest
winds will persist into tonight with gusts up to 35 kts. This could
contribute to visibility restrictions in blowing snow at IWD and
CMX.
&&
.MARINE...
Issued at 408 PM EDT Mon Apr 14 2025
As low pressure northeast of Lake Superior continues to depart the
region, west to northwest gales of 35-40 kt will ramp up to 40-45 kt
tonight, especially over the central to eastern Lake Superior.
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...
Wind Advisory until 2 PM EDT Tuesday for MIZ001-003.
Winter Storm Warning until 11 AM EDT /10 AM CDT/ Tuesday for
MIZ001>003-009-084.
Lakeshore Flood Advisory until 11 AM EDT Tuesday for MIZ001.
Winter Storm Warning until 2 PM EDT Tuesday for MIZ004.
Winter Weather Advisory until 2 PM EDT Tuesday for MIZ005.
Wind Advisory until 8 PM EDT Tuesday for MIZ005>007-014-085.
Winter Weather Advisory until 8 PM EDT Tuesday for MIZ006-007-
085.
Lakeshore Flood Advisory until 11 PM EDT Tuesday for MIZ006-
007.
Lake Superior...
Gale Warning until 8 AM EDT /7 AM CDT/ Tuesday for LSZ162.
Gale Warning until 10 AM EDT /9 AM CDT/ Tuesday for LSZ241-242-
263.
Gale Warning until 1 PM EDT Tuesday for LSZ243>245-248-264-265.
Gale Warning until 11 PM EDT Tuesday for LSZ249>251-266-267.
Lake Michigan...
Gale Warning until 2 PM EDT Tuesday for LMZ221-248-250.
&&
$$
SHORT TERM...BW
LONG TERM...GS
AVIATION...TDUD
MARINE...GS