Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/13/24
Area Forecast Discussion
National Weather Service Aberdeen SD
804 PM CDT Wed Jun 12 2024
.KEY MESSAGES...
- After 10 PM CDT, an additional round of near 30% chances of
showers and thunderstorms will sets up over central SD and
persist into Thursday morning.
- Temperatures will be closer to normal Thursday and Thursday
night, along with dry conditions.
- A more active weather pattern sets up on Friday afternoon and
continues into early next week. This will bring multiple
opportunities for showers and thunderstorms to the region (near
50% chance). While there is an opportunity for severe weather
most days, the greatest chance for severe weather (15%) is
highlighted by the Storm Prediction Center on Monday in eastern
SD.
&&
.UPDATE...
Issued at 802 PM CDT Wed Jun 12 2024
Severe Thunderstorm Watch 405 has been cancelled, as storms have
moved out of the area. Convection has quickly diminished after
00Z, with only a few clouds lingering from Clark to Watertown and
Clear Lake. Will update the forecast to diminish the clouds faster
than originally anticipated. Otherwise, the forecast remains on
track.
&&
.SHORT TERM /THIS EVENING THROUGH THURSDAY NIGHT/...
Issued at 223 PM CDT Wed Jun 12 2024
At 2 pm CDT, temperatures were warming through the 80s, and in
several places were already nosing up into the low 90s. Skies were
generally partly to mostly sunny. Winds out ahead of a surface cold
front analyzed from northern Brown County southwestward into Buffalo
County were southwest around 10 to 15 mph, with some occasional
higher gusts, while behind the front, winds have shifted to the
northwest and are running closer to 15 to 25 mph with occasionally
higher gusts. The last remaining pesky convection from earlier this
morning finally fizzled out over Hand County.
Severe storm potential remains basically unchanged. The deep layer
shear this afternoon/evening supports supercell thunderstorms. The
low level shear is weak and basically rules out the possibility of
tornadoes in this CWA. But, the instability is quite large, with SPC
RAP instability forecast to increase to and then hold around 2000-
3000J/kg of MLCAPE through 23Z. Hail CAPE is still advertised at 750-
1050J/kg and low/mid level lapse rates are quite steep. Downdraft
CAPE is forecast to be around 1100-1750J/kg, so there is definitely
a supercell downdraft/strong wind concern. But, the biggest concern
is for very large hail (1.75in to 2.50in hail) over the far
eastern CWA, mainly east of a line from Hecla to Waubay to Clear
Lake between 21Z and 02Z. West and south of that line depiction,
areal coverage of the mid-level capping inversion (+10C or warmer)
looks to reside and should basically preclude the potential for
convection. Plus, without a clearly defined shortwave (PVA) moving
through, it will be harder to get updrafts to go and be sustained
(just a 110+knot upper level jet streak in the region, but not in
the proper quadrant for supportive lift) as there is a capping
inversion (albeit weaker) still to be overcome even in the far
northeast corner of the CWA. On a mesoscale note, there is outflow
air (an OFB) moving north of SD Hwy 20 this afternoon from
earlier convection. This boundary (plus any other boundaries that
may be around farther east from earlier convection that can`t be
detected by the 88D) will have to be monitored as one more source
of focused low level forcing/lift for convective initiation as it
moves further away from the warmer/stronger mid-level capping in
place.
Elevated showers/storms are still possible overnight within the
trailing/southward-shifting mid-level baroclinic zone over the
region and that impressive upper jet streak in play. Precipitation
potential should be waning considerably by 15Z Thursday.
Most of Thursday should be dry and a bit cooler than Wednesday`s
readings in the 90s. Thursday night should be dry as well with high
pressure over the region.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 223 PM CDT Wed Jun 12 2024
The upper ridge that will develop over the northern part of the
CONUS on Thursday will quickly push east and over the Dakotas on
Friday and then into the Great Lakes on Saturday. This will set our
region up for an unsettled weather pattern for the long term part of
the forecast, as the ensemble clusters are very consistent on an
upper trough gradually moving through the Pacific Northwest this
weekend and stalling over the Mountain West through at least the
first half of next week. This will lead to southwesterly flow aloft
over our region, and a series of upper level disturbances and
associated surface lows moving through. While this whole period
isn`t going to be a washout (and some locations may see limited
precipitation), there will be several opportunities for
precipitation and most locations have 30-60% rain chances through
the extended.
Starting with Friday, high pressure will be in place at the start of
the day while a surface low develops in eastern WY through the
afternoon. This will lead to increasing southeasterly flow and in
turn moisture/instability. Best instability plume is off to the west
of our CWA, but could see storms persisting eastward into our CWA
(storm motions to the ENE at 20kts), but diminishing with time as
the MUCAPE diminishes towards the Missouri River. Still could see
some weak showers pushing east across northern SD overnight, while
the better forcing focuses farther south into southeastern SD and
associated with a better shortwave lifting northeast through NE and
into IA/MN Friday night into Saturday. That area has the best
precipitation potential, but we still should see some potential for
heavier rain on the northwest side and over east central SD (15-35%
chance of 0.5" of rain in 24hrs ending at the end of the daytime
Saturday). Farther northwest, a cold front or surface trough looks
to move through during the Sat into early Sun period (uncertainty
remains in ensembles on timing/intensity). We do see instability
increase ahead of this trough/front, but also the potential for
capping with a good warm nose at 850-700mb. Shear does look to be
less impressive on Saturday in our area (20-25kts ahead of the
front/trough and better into wrn ND were there are increased CSU ML
probs of 15%), so overall severe threat does look lower during this
time.
Sunday will depend on where the front/trough that moves through Sat-
Sat night stalls out. Latest ensemble trends have it stalling in the
NE/IA/MN/southeast SD area, so largely to the southeast of our CWA.
That should limit the precipitation potential for our area on
Sunday.
Precipitation chances do increase on Monday, with ensemble clusters
showing increasing instability on the inverted surface trough
(previously mentioned weekend front/trough that stalls) stretching
from the low in eastern CO and through southeast SD and into MN.
Some differences in the location of the trough, so exact details are
too uncertain at this point and it`s possible the trough stays south
of us. But where that instability/lift sets up, we have ample shear
in place (40-55kts) and would support severe storms when/where they
develop. Thus, the Day 6 15% severe risk from SPC looks to be
reasonable at this time. This is also highlighted in EC-Ens EFI
values (0.6-0.7) in the CAPE-Shear realm across much of our CWA,
which aligns where the overlap of the better instability/shear is
located. Finally, 00Z GEFS based CSU ML severe probs also
highlighting this period with 15% probs over eastern SD into
central/southern MN. In addition to the severe storm potential, NBM
probabilities of 0.5" of rain on Monday increase to 30-40% over much
of the CWA, with the highest values over the east. Even greater
uncertainty on where the overall setup of instability/shear will be
for Tues/Wed, but it does look to slowly shift farther to the
east/southeast with time.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 802 PM CDT Wed Jun 12 2024
Terminals KABR,KATY,KPIR,KMBG
VFR ceilings and visibility are expected over the next 24 hours.
Storms have come to an end over eastern SD (near ATY).
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...KF
SHORT TERM...Dorn
LONG TERM...SRF
AVIATION...Dorn
Area Forecast Discussion
National Weather Service Cheyenne WY
942 PM MDT Wed Jun 12 2024
.KEY MESSAGES...
- Hot today. Scattered to numerous high-based showers and a few
rumbles of thunder in the afternoon and evening, possibly
associated with 45+ MPH wind gusts.
- Isolated thunderstorms Thursday along and east of the Laramie
Range.
- Widespread showers and thunderstorms are expected across the
high plains on Friday. Some storms may be severe, with all
hazard types possible.
&&
.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 311 PM MDT Wed Jun 12 2024
Hot, dry weather so far today across southeast WY and western
NE with an upper level ridge building over the central Rockies.
Most areas have reached the upper 80s to 90s with KBFF hovering
around 100F degrees at this hour. Latest GOES visible imagery
shows weak convection over south-central WY resulting in showers
with occasional lightning near Baggs and the Sierra Madres.
Based on latest RAP soundings west of the Laramie Range, LCLs
extending well above the freezing level with dry low-levels will
support the potential for gusty, erratic winds around 45 mph in
the vicinity of showers through late this afternoon. Hi-res
guidance continues to push convection farther east along the
I-80 corridor through early this evening with minimal precip
accumulation.
Better chances for showers and thunderstorms arrive later this week,
starting on Thursday. Post-frontal upslope flow with an upper level
system passing over the central CONUS will increase moisture
convergence across southeast WY and northeast CO. Despite
southeasterly low-level flow, wind profiles are fairly
unidirectional aloft supporting of straight hodographs and splitting
storms. However, slightly better turning of the wind profile is
noted closer to the Laramie Range near Cheyenne with the latest
NAMNest showing higher 0-3 km SRH values near 200 m^2/S^2. MLCAPE
with latest HREF guidance is generally below 1000 J/kg, but
additional moisture pooling along the Front Range with 40+ kt shear
could support strong to severe thunderstorms Thursday afternoon,
especially near the CO/WY/NE border.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 311 PM MDT Wed Jun 12 2024
Friday still looks to be the most active day in the long term
forecast. Throughout the day Friday, a potent, upper-level,
negatively tilted, shortwave trough will dig northeasterly out
of the Four Corners region across the Intermountain West. Ample
synoptic lift will be present ahead of the shortwave as it digs
towards the region. Strong 500mb cyclonic vorticity advection
will move overhead, further enhancing lift across the region.
Further down, at 700mb, a compact low-level jet attempts to
develop across far northeastern Colorado and southwestern
Nebraska. There is slight disagreement on the exact placement of
this jet, with the GFS suggesting a further west jet than the
ECMWF and NAM. However the NAM suggests a secondary, weaker,
low-level jet positioned across the Wyoming/Nebraska border. If
either the GFS or NAM solution comes to fruition, the CWA will
be under additional synoptic left from the jet dynamics surround
the low-level jet. However, if the ECMWF solution pans out, the
jet will probably be too far east to provide any additional
lift to the region. The big story is found closer to the
surface, where a moisture tongue will move overhead into the
region. Dewpoints across the Panhandle will increase into the
low- to mid-60s, with dewpoints into the low- to mid-50s across
southeast Wyoming. Southeasterly surface winds will continue to
advect moisture into the region throughout the morning and
afternoon hours, keeping ample moisture in the region. A dryline
is expected to develop across the Laramie Range and progress
easterly through the day before interacting with these high
dewpoints across the Panhandle. This will likely act as the
storm initiation mechanism, with storms moving into an excellent
environment as the fire and move off the dryline. MLCAPE and
MUCAPE values are progged to skyrocket towards the 3000 J/kg
across the Panhandle, according to the NAM. The GFS is much less
excited with the instability, but suggests CAPE values to be in
the 2500 J/kg range.
The one failure mode for severe storms on Friday will be the
relative lack of shear depending on exactly where storms fire across
the Panhandle. Northern portions of the Panhandle suggest favorable
shear with SRH values in the 150-200 range. However, further south
where the moisture will likely be better, limited shear is shown in
forecast soundings with minimal SRH values. Effective shear to the
south is around 30kts, which is still enough to get storms, but
would like to see more shear for a more significant threat of hail
and/or tornadoes. Further north could see a higher potential for
hail and, maybe, tornadoes. Therefore, we could see two separate
modes of convection depending on where storms form. The northern
threat may be hail producing storms, while the southern threat will
be heavy rain and flooding. According to the NAEFS, PW values will
be in the 95-99th percentile on Friday afternoon for much of the
Panhandle, with forecast soundings suggesting PW values well over
the 1 inch mark. Therefore, slow moving storms, with ample moisture
will lead to heavy downpours and the threat for flash flooding
across the Panhandle. Large hail could still be a threat with any
storms that form due to the strong instability throughout the
atmosphere and decent lapse rates, but flash flooding will likely be
the largest threat. SPC has most of southeast Wyoming and western
Nebraska in a Marginal Risk for severe weather, with a sliver of a
Slight Risk clipping Cheyenne County. WPC currently highlights a
Marginal Risk for excessive rainfall across a small portion of the
CWA. It is possible that these threats will progress further west
with future updates, but this setup will be something to watch over
the coming days.
The remaining long term forecast looks to be quieter than Friday as
southwesterly flow aloft moves overhead. An upper-level trough is
progged to move into the western CONUS with southwesterly flow ahead
of it over the CWA. There is some differences between long range
models as far as the progression of this trough. Both the ECMWF and
GFS suggest this low deepening across the western CONUS by Monday.
However, the GFS flattens this trough by Tuesday evening and ejects
if further to the northeast, keeping the CWA under weaker
southwesterly flow. The ECMWF on the other hand continues to deepen
the trough through Wednesday, with a large trough across much of the
western CONUS with strong jets on either side. With the GFS
solution, 700mb tank into the 1-8C range, while the strong upper-
level flow with the ECMWF heats 700mb temperatures into the 15-18C
range, before dropping them back into the 10C range as the trough
moves out of the region Wednesday. This leads to significant
uncertainty in the Tuesday temperature forecast. The GFS solution
suggests highs in the mid-60s while the ECMWF keeps them closer to
the upper-70s and low-80s across the region. Decided to keep the
Tuesday forecast closer to the GFS solution, but this will need to
be monitored. Daily precipitation chances return Monday through the
remaining long term due to the upper-level trough to the west.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 938 PM MDT Wed Jun 12 2024
VFR conditions expected overnight into most of Thursday. Winds
shift northeasterly Thursday as a cold front drops south across
the area from South Dakota and northern Wyoming. Showers and
thunderstorms expected to increase along this front Thursday
afternoon and evening...especially along and just east of the
Laramie Range. Some concern with lowering flight conditions
Thursday evening as the Panhandle and areas east of the Laramie
Range remain in easterly upslope flow. Started trending sky
conditions down with scattered lower clouds. Once we know which
airports will go down...will add lower conditions into TAFs.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...MB
LONG TERM...AM
AVIATION...GCC
Area Forecast Discussion
National Weather Service Des Moines IA
632 PM CDT Wed Jun 12 2024
...Updated for the 00z Aviation Discussion...
.KEY MESSAGES...
- Showers and thunderstorms earlier today with more possible
later this evening.
- Robust thunderstorms expected across southern Iowa tomorrow
afternoon with severe storms and heavy rain likely,
- Hot through the end of the week and early next week with
temperatures in the 90s and heat indicies in the low 100s for
some.
&&
.DISCUSSION...
Issued at 243 PM CDT Wed Jun 12 2024
Showers and thunderstorms have moved across northern Iowa from late
morning into the early afternoon. Very dry air is in place near the
surface, most notable in soundings which show over 1200 J/kg of
CAPE, steep lapse rates, and a deep inverted-V shape. This has
resulted in breezy environmental winds with convection
enhancing the winds further. So far gusts in northern Iowa with
showers have gusted 40-55+ mph. The more robust thunderstorms
are shifting off to the east this afternoon, but showers will
linger across the area into the after across the area. Much
later this evening a secondary round of thunderstorms is
expected to sweep across norther area, skimming northern
portions of the area. HREF runs this morning have shown UH
tracks identifying better updrafts mainly across northern to
northeast Iowa very late tonight. Gusty winds will remain a
concern, along with hail with good updraft support, with any
storms that develop in the area overnight. This will weaken
towards early morning and continue to move into eastern Iowa
and parts of Wisconsin and Illinois.
Our attention then turns to Thursday. Another embedded wave will
pass across the area with a boundary hanging up across southern Iowa
in the afternoon. This boundary will provide the focus for
thunderstorms develop in the afternoon and evening. Expect to
see much more robust convection on Thursday with SPC increasing
to an Enhanced (Level 3 of 5) in southeast Iowa. Storms will
have no problem initiating with a boundary to fire on and CAPE
of 2000-3000 J/kg, along with another inverted-v sounding shape.
This will be highly supportive of gusty winds with storms and
larger hail with strong updrafts. CAMs have been fairly
consistent in developing gusty wind with the storms that develop
in southeast Iowa, including the HRRR consistently putting out
some high end thunderstorms gusts. Given similar dry air in
place with doubled instability tomorrow, this makes sense with
the gusts we`ve seen so far today. Tornadoes would also be
possible, though not the main concern, with modest SRH in
soundings and curved low level hodographs. Also of concern is
hydrologic impacts. Weak flow keeps storm motions slow and
storms in CAMs look to look to line up and train along the
boundary. PWATs are 2"+ in the vicinity of the boundary in
southeast Iowa, so a few areas could pick up some heavier rain.
At the same time, heat will continue to be a concern with
temperatures into the 90s across central and southern Iowa with
heat indicies in southern Iowa pushing 100 degrees.
Temperatures moderate some into Friday and Saturday, but it will
still remain pretty warm with temperatures into the 80s. Additional
thunderstorms are possible into Saturday with another wave passing
across the area. The pattern remains active into early next week
with another robust wave progged for Monday. This one could bring
another chance for severe storms with SPC outlining a day 6 outlook
in our north. At the same time heat continues to build into early
next week with temperatures in the 90s and heat indicies near 100.
There will be little relief overnight as low still remain in the
70s.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 630 PM CDT Wed Jun 12 2024
While there are chances for a few stronger showers/storms during
the TAF period, have kept away from any prevailing TS mentions.
Do have VCTS at KMCW/KALO for a couple hours around/after 06z
with expectation continuing for scattered convection. Otherwise,
VFR conditions prevail with southerly winds eventually turning
northerly as a front drops down/through the state. Winds remain
largely under control with prevailing winds predominantly around
10 to 15 kts or less.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...Hagenhoff
AVIATION...Curtis
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1157 PM EDT Wed Jun 12 2024
.KEY MESSAGES...
- Warming trend continues through mid-week with high temperatures
nearing 90 degrees for Thursday.
- Scattered showers and thunderstorms also arrive Thursday. Strong
to severe storms will be possible during the afternoon and evening
with damaging winds and large hail the main threats. Southeast MI
is outlined in a Marginal to Slight Risk from SPC.
- Higher than usual confidence in hot and humid conditions next week.
Temperatures into the 90s Monday and Tuesday with relatively high
humidity will likely bring the highest heat indices we have seen so
far this year.
&&
.AVIATION...
A combination of thunderstorm remnants moving in from the west and
new showers developing overhead are expected to affect MBS down
toward Flint late tonight and early in the morning. The ongoing
activity weakens enough for conditions to remain VFR while any new
showers are also high based and light. The plume of mid level
moisture tracks east mid to late morning which gives daytime heating
a chance to recover for the afternoon. Thunderstorm timing,
coverage, and intensity the become the forecast highlights for the
afternoon into Thursday evening. There is a wide range of model
projections on timing/location of storm initiation, however earlier
and/or farther north solutions are favored as the larger scale mid
level trough and upper level jet approach from the upper Midwest.
Storms are expected to affect all terminals beginning around 20Z at
MBS then spreading southeast toward DTW during late afternoon.
For DTW/D21 Convection... An approaching low pressure system and
cold front bring a chance of thunderstorms later in the afternoon. A
general NW to SE progression with increasing coverage is expected
across the area, primarily affecting DTW after 22Z.
DTW THRESHOLD PROBABILITIES...
* Moderate for thunderstorms impacting the terminal after 22z
Thursday.
&&
.PREV DISCUSSION...
Issued at 957 PM EDT Wed Jun 12 2024
UPDATE...
Upstream observational trends this evening suggest the forecast is
in good shape calling for a chance of showers and possibly a rumble
of thunder late tonight and in the morning. The WI/IL convection has
weakened but the parent MCV remains with respectable strength while
set to track across Lower MI. The wave has some representation at
500 mb across the spatial range of model data and appears capable of
strengthening the low level jet with a corresponding increase in
elevated moisture transport and instability late tonight. This
forcing has potential for scattered shower production in its own
right out ahead of any remnant surface based activity approaching
from the upper Midwest. Consensus of hi-res model data carries the
bulk of the upstream storms across Upper Mi and northern Lower MI
along the instability axis. The latest runs of the RAP and NAM also
maintain a couple line segments of convection this far south toward
sunrise. This will be monitored as MUCAPE drops to sub 1000 J/kg
from west to east into SE MI, however lapse rate in the 700-500 mb
layer builds into the 6-7 C/km range toward sunrise, sufficient for
late developing elevated/nocturnal convection. The most favored area
is north of I-69 and mainly within a few hours of sunrise. Activity
dissipates while exiting eastward mid to late morning allowing ample
opportunity for recovery of instability for the anticipated afternoon
round of storms.
PREV DISCUSSION...
Issued at 320 PM EDT Wed Jun 12 2024
DISCUSSION...
Clear skies have pushed temperatures into the 80s this afternoon
ahead of the approaching cold front and associated storms moving in
tomorrow. Hi-Res guidance resolves two different chances for rain on
Thursday. The first round comes through early Thursday morning,
beginning as early as 4am. This threat for storms is focused mainly
in the Thumb, where there is potential for the storms to tap in to
some MUCAPE of up to 500 J/kg. By the time the rain moves in, shear
looks to be scarce and a diurnal temperature inversion will be in
place. Currently not expecting any severe storms to develop,
although an occasional rumble of thunder is possible.
The second round on Thursday boasts a greater potential for storms
to develop, but there is still much uncertainty on how everything
will play out. Later in the day Thursday a shortwave trough moves
overtop Michigan, allowing for a bit more divergence aloft than
earlier in the day. That said however, the left exit region of the
trough remains to the northeast, meaning that speaking dynamically,
the best region for storm development is still not quite lined up
with the CWA. Thermodynamics tell a similar story for a different
reason, with the better CAPE and moisture environment staying to the
southwest. ThetaE values range 10-20K greater to the southwest of
Lake Michigan, allowing for the possibility that storms may grow in
the direction of greater moisture rather than developing over
southeast Michigan. MUCAPE values over Michigan reach 1500 J/kg at
their peak, so updrafts still have the possibility to develop with
some help from the cold front. Hodographs look decent for the
development of supercells with the potential to produce hail, and
DCAPE values over 1000 J/kg signify the potential for severe wind
gusts. An isolated tornado can also not be ruled out at this time.
The cold front then passes over Michigan early Friday morning,
ending the severe storms chances.
High pressure takes control behind the front, bringing clear skies
Friday and Saturday along with slightly cooler, more seasonal
temperatures. The next chance for showers comes Sunday evening, when
a shortwave embedded within the development of an upper level ridge
brings some rain to the Great Lakes area. The timing and extent of
these showers is still uncertain, and depends on how the ridge
develops over the weekend.
Confidence continues to stay high on a significant warmup next week.
An upper level high settles in over the Southeast United States on
Sunday creating the aforementioned ridge overtop of the CWA. 500mb
heights have the potential to hit 590dam at peak, allowing for
temperatures 10-15 degrees above climatological normals. Flow is set
up in such a way that will allow for warm, moist mT air from the
Gulf of Mexico to fill in to the Great Lakes, bringing dew points up
into the 70s. Forecasted temperatures currently sit only a few
degrees shy of record highs across the area, and has the potential
to hit record highs if full insolation can be achieved. Ensemble
guidance shows only a handful of runs failing to hit 90 degrees on
Monday, with apparent temperatures reaching into the mid-to upper
90s. The same factors remain in place on Tuesday, with temperatures
and apparent temperatures once again reaching the low 90s and upper
90s respectively. Overnight temperatures stay in the 70s, offering
little relief from the hear. As such, the NWS Heat Risk product
identifies a Major Risk (Level 3/4) of heat related impacts on
Monday and Tuesday, with local pockets of Extreme Risk (Level 4/4)
on Tuesday. Showers are possible for the duration of the event
riding up the trough to the west into the Great Lakes region, which
could provide some brief relief from the heat. Still, much remains
to be resolved on the extent and timing of any rainfall.
A slight though not insignificant cooling trend has developed for
Wednesday. Previous runs looked to maintain the ridge through the
middle of next week, but now look to move it off to the east on
Wednesday. Zonal flow is set to take over, but temperatures will
remain above normal through the rest of the week.
MARINE...
Extremely stable over-lake conditions persist through the remainder
of the day which will promote light winds leading into tomorrow.
Upstream convection west of Lake Michigan will eventually cross the
lake and enter, first over northern Lake Huron, which will bring the
chance for showers and thunderstorms. Coverage and intensity of
activity is expected to wane overnight as it crosses both lakes, but
isolated to scattered coverage cannot be ruled out through southern
Lake Huron into late tomorrow morning. Southwest flow will become
reinforced over the lake through the day tomorrow, veering more
northwesterly late tomorrow night into Friday morning. Gusts 20-25
knots will be possible immediately along the nearshore zones,
especially through Saginaw Bay with the better fetch, however, have
precluded the issuance of any Small Craft Advisories at this time
given how stable the over-lake conditions continue to be. The stable
marine layer should keep the stronger winds aloft as they flow off
the land. Will consider a Small Craft Advisory for the Saginaw Bay
tomorrow afternoon and evening if modeled guidance suggests higher
probabilities of achieving sporadic gusts aoa 22 knots. Wave heights
reach right around the 3 ft mark for the Bay. A cold front and high
pressure builds in on Friday, promoting lighter winds speeds.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&
$$
AVIATION.....BT
UPDATE.......BT
DISCUSSION...BC
MARINE.......AM
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Quad Cities IA IL
653 PM CDT Wed Jun 12 2024
...Updated for 00z Aviation...
.KEY MESSAGES...
- Rain/Storms possible through the next 24-48 hours, with strong
to severe storms possible. Main threat for severe weather will
be tomorrow afternoon and evening.
- Unseasonably warm temperatures will invade the area,
especially through to the upcoming weekend. Many will see
temperatures approach or exceed 90. Humid conditions may
result in excessive heat for some!
&&
.SHORT TERM /THROUGH THURSDAY/...
Issued at 215 PM CDT Wed Jun 12 2024
Tonight...
Weak wave approaching from the northwest through the evening and
into tonight, which will bring the potential for a round of showers
and storms tonight after midnight. Moisture remains lacking in
areas, which will limit the spatial coverage, with lower instability
limiting the severity. Through the last couple of model runs, short
term guidance has trended in favor of scattered showers and
storms, along with their longevity. HREF guidance has even
caught on to this and also noted an increase in instability.
Timing will generally be storms moving in from the northwest
shortly after midnight, with storms reaching the Quad Cities
area between 4-6am. From there, quick decay of the storm can be
seen through the AM commute. Guidance keeps the activity below
severe limits for the most part, but some strong to severe
cannot be ruled out. SPC highlights our northwest in a Marginal
Risk for Severe Weather once again tonight and into Thursday
morning, highlighting winds and hail as the main threats in any
strong storms that we see.
Thursday...
Tomorrow has become a day that we must remain weather aware, as our
severe threat has increased and expanded throughout our area. To
preface, we now have an Enhanced Risk for Severe Weather (level 3/5)
for areas along and south of Interstate 80. Much of the remaining
area will fall under a Slight Risk (level 2/5). The timing will
generally fall within an 8-hour period, between the hours of 2pm-
10pm, with storms moving from northwest to southeast.
So, what exactly are we dealing with? Well, the cold front that
induced showers and storms for parts of the area overnight tonight
(Wednesday night) will slow down on its approach, with the cold
front generally draped west to east over the Interstate 80
corridor around noon Thursday. The location of this boundary
prior to peak heating will be key, as any location along/south
of the cold front and in the warm sector will see a chance for
severe weather. Those north of the front will have lower chances
for severe, yet nonzero, as some guidance hints at some post
frontal development tomorrow. So, with the cold front moving
through in the afternoon, our unseasonably warm and moist
conditions will allow for rapid/robust thunderstorm development.
For reference, our temperatures will largely be in the 90s,
with dewpoints in the low- mid 70s. This will result in
moderate to high instability, which will be conveniently located
in an area of sufficient shear for organized/severe storms.
Thus, we have three of the main ingredients in place for severe
storms, which is shear, instability, and surface forcing. Given
such warm and humid conditions ahead of the boundary tomorrow, I
wouldn`t be shocked to see some convective initiation earlier
in the afternoon, ahead of the main convective cluster.
Now onto storm mode and hazards. Storm mode is expected to be messy
tomorrow. While we may start out with discrete to semi-discrete
convection, we are expecting convection to grow upscale rather
quickly, with embedded supercell structures. All hazards will be
possible on the more discrete storms, with hail and winds remaining
the main threat. The earlier convection may be the best chance to see
significant hail (2" or larger), prior to upscale growth. Although,
once upscale growth begins, we will start to see that wind threat
ramp up quickly. The HRRR and NAM are catching onto this, with them
even highlighting the potential for significant winds (>75 mph). All
of this is supported by the SPC, who has much of our area hatched
for these hazards, signifying the potential for significant severe.
Thus, our confidence is increasing in the likelihood of severe
weather. The tornado threat will be low during all convective modes,
with only a 2% chance highlighted south of Interstate 80 tomorrow.
Thus, be prepared for all hazards, but keep in mind that hail and
wind are our main concern at the moment.
As was mentioned, it will be hot and mostly sunny tomorrow. So, if
outside, please take proper precautions in the heat and have
sunscreen handy! Areas along and south of Interstate 80 will have a
chance to see heat index values around 90-100.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
Issued at 215 PM CDT Wed Jun 12 2024
Incoming LLVL ridging under temporary northwesterly steering flow
will make for some nice summer days Friday through Saturday, with
the bulk of the warm-up being seen Saturday into Sunday. Friday will
be a beautiful end to the week, with high temperatures in the
low- mid 80s and a light northwesterly breeze. One of the
failure modes for these very warm temperatures will be the track
of the ridge- riding MCSs that result from this pattern. This
would bring residual cloud cover and convection in the mornings,
shunting much of the morning heating. Although, if we fall
south of that track, we will fall under that dome of hot air.
Guidance remains quite aggressive with the heat this weekend
into next week, showing widespread low- mid 90s. If this ends up
being the case, some heat headlines may be necessary. Although,
much uncertainty exists and will refrain from any further
details.
Have plenty of water and sunscreen handy!
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 645 PM CDT Wed Jun 12 2024
Periodic chances for showers and storms exist during the TAF
cycle. Initially this evening (mainly showers) near/north of
CID and DBQ terminals in the vicinity of an outflow boundary and
a weak disturbance approaching from north central Iowa.
Another chance will occur late tonight and early Thursday AM
(08z-13z) with warm air advection with another approaching
disturbance. Then an increasing and more widespread potential
evolving by Thursday afternoon into evening ahead of a cold
front. Have opted to leave out any mention of showers at CID/DBQ
this evening given the limited coverage and impact. The late
night and early Thursday AM chance was handled with PROB30 mention.
And, despite the likelihood of storms Thursday afternoon into
evening, I`ve opted for PROB30 mention given that the timing is
in the last 6 hours of the TAF. These PM storms will have the
greatest severe weather potential in the form of large to very
large hail and damaging winds 60-80 mph. Where the stronger
convection occurs expect transitory periods of MVFR to IFR
conditions. Otherwise, VFR conditions will largely dominate.
Winds will be a bit challenging. DBQ winds will start out E/NE
5-10 kts in the wake of an outflow boundary, but then eventually
veer around to SSW around 10 kts tonight. The outflow boundary
is slowing and so lower confidence exists on it reaching CID,
thus have kept SSW winds around 10 kts there and also at MLI and
BRL tonight and also Thursday AM when likely see some periodic
gusts 12-19 kts. Thursday afternoon through evening winds will
gradually turn northerly from north to south across the
terminals, as a cold front moves through the region.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...None.
MO...None.
&&
$$
SHORT TERM...Gunkel
LONG TERM...Gunkel
AVIATION...McClure
Area Forecast Discussion
National Weather Service Green Bay WI
1050 PM CDT Wed Jun 12 2024
Updated aviation portion for 06Z TAF issuance
.KEY MESSAGES...
- There is a chance of strong to severe thunderstorms across all
of north-central and northeast Wisconsin after 9 pm tonight.
Overall confidence in the severe weather threat is medium-low,
but a few of the strongest storms may produce strong to
damaging winds and hail.
- Well above normal temperatures are forecast from Sunday into
the middle of next week. Heat indices may surpass 90 degrees at
times.
- The next chance for widespread rainfall arrives Saturday, with
the best coverage Saturday evening through the overnight. It is
uncertain if these storms would become severe, but locally
heavy rainfall will be possible.
&&
.DISCUSSION...
Issued at 242 PM CDT Wed Jun 12 2024
Short Term...Tonight and Thursday
The latest RAP analysis and satellite/radar imagery show
relatively fast zonal flow in the mid and upper levels across the
US-Canadian border with embedded shortwaves within said flow. In
fact, the 200mb and 500mb flow is upwards of the 97.5 percentile.
This flow is above a warm front lifting northeast across Minnesota
and a trailing cold front across North Dakota. An area of showers
ahead of these features is slowly decaying over northern WI,
while more intense thunderstorm activity resides across southern
Minnesota and southwest Wisconsin. These thunderstorms are
expected to continue to move southeast and bypass central
Wisconsin. The area behind these showers and storms over northern
Minnesota is where greater concern lies as this area has seen
strong solar insolation and destabilization this afternoon. Storm
initiation is expected in the 3-4 pm timeframe in this area.
Evolution of these storms and the severe storm potential are the
focus of this forecast.
Precipitation Trends and Severe Thunderstorm Potential: While
it`s possible that some additional shower and storm activity could
redevelop behind the ongoing convection over central and southern
Minnesota, odds appear considerably reduced as the atmosphere
will have little time to destabilize prior to peak heating. If
storms redevelop, the airmass over central Wisconsin is
considerably more stable and likely to keep the severe threat very
low.
A considerably higher potential for severe weather is likely to
arrive from the storms that initiate over northern Minnesota.
These storms are forecast to track southeast towards north-central
WI in the 9 pm to 11 pm time frame. The airmass will be more
stable over northern WI than upstream by this time, and the storms
will likely be in the weakening process. Despite this, most
unstable capes upwards of 1000 j/kg will likely lead to a severe
threat continuing as storms arrive into north-central WI,
especially with deep layer shear from 40-50 kts. With such strong
wind fields aloft, strong to damaging winds will be the primary
threat tonight, but updrafts may be strong enough for large hail
to remain possible, at least over north-central WI. The threat of
damaging winds will likely persist, however, as forward
propagating vectors indicate a storm motion of 55-70 kts. The
chance of storms will end towards the middle of the overnight.
Thunderstorm Potential and Gusty Winds on Thursday: Thunderstorm
activity will likely push the cold front into southern Wisconsin
or northern Illinois by Thursday morning. However, ahead of a
secondary front and shortwave trough, models indicate 1000-1500
j/kg of cape developing over central and east-central WI by late
morning to early afternoon. Think widely scattered showers or
storms could develop in this unstable airmass and have added a
small chance to the forecast. Strong wind fields aloft could lead
to a gusty wind threat if storms develop.
Deep mixing through 6-8k feet should tap into strong winds aloft,
resulting in west winds gusting to around 30 mph in most areas.
Gusts should not be as strong over Lake Michigan, due to more
stable conditions over the relatively cool waters. Thus, expecting
gusts to remain below the 25 knot threshold for a Small Craft
Advisory.
Long Term...Thursday Night Through Wednesday
The two concerns in the extended period will be the potential for
another round of impactful weather moving through the region
Saturday and the much warmer weather anticipated by the end of the
weekend into early next week.
Saturday...
After a quiet start to the extended, active weather returns to the
region as southerly flow picks up again. As warm air advection
increases, showers are expected to develop across the region
Saturday afternoon. Although initial rain will only have a minimal
chance for thunder, the overall potential for stronger storms
increases as we get into the overnight hours. A strong low level
jet is expected to develop in the evening hours, helping to
sustain and strengthen any ongoing showers. With lingering MLCAPE
around 1000-1250 and strengthening shear, wouldn`t be surprised to
see an increase in elevated thunderstorm coverage. Whether
instability and shear remains sufficient for severe weather
remains uncertain. PWATs during this time will also push to
around 1.8-2.0, which will make heavy rainfall a concern,
especially if these storms start training along the warm front. A
few showers and storms may linger on to start off Sunday, which
may skew the high temperatures expected in the region.
Temperatures...
The push of the warm front from Saturday will bring with it some
well above normal temperatures. Highs could be well into the 80s
by Sunday, although this may change slightly depending on how
quickly clouds and active weather move out of the region Sunday
morning. Dewpoints during this time are also expected to push
towards the upper 60s which may make for one of the muggier days
so far this year.
Behind the Sunday system, temperatures early next week will remain
well above normal, with highs into the upper 80s both Monday and
Tuesday. A few of the warmer spots may even hit 90 during this
timeframe. With several days of very warm temperatures in the
forecast, make sure you have a way to beat the heat!.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1050 PM CDT Wed Jun 12 2024
A cluster of showers and thunderstorms will continue tracking
through the TAF sites during the overnight hours from northwest to
southeast. The strongest storms could produce small hail and gusty
winds, but should remain below severe limits. This activity will
wane through early Thursday morning. Conditions could briefly drop
to MVFR with the showers and thunderstorms.
In the wake of the storms, MVFR low clouds may stick around for a
time over far northern WI, including RHI, but then clear for a
time on Thursday morning. Convective clouds are then expected to
build over east-central WI by late morning, which could lead to
scattered showers developing.
Gusty west winds to 25 kts are possible at the taf sites on
Thursday.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION.....MPC/Uhlmann
AVIATION.......Kurimski
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
706 PM CDT Wed Jun 12 2024
.KEY MESSAGES...
- Weakening showers/storms may move into the northern portion of
the CWA late tonight or early tomorrow morning.
- Level 2 to 3 out 5 risk for severe weather Thursday afternoon/evening
for large hail and strong winds. There is also a localized
flooding threat.
- Hot and humid conditions likely to develop early next week,
particularly on Monday.
- Periodic chances for showers and storms next week as well.
&&
.UPDATE...
Issued at 501 PM CDT Wed Jun 12 2024
We are monitoring a small complex of storms moving ESE across
southwest Wisconsin that has showed some increase in strength
late this afternoon. This is primarily in response to a long-
lived MCV emanating from storms in the northern Great Plains
early this morning. The downstream environment remains only
slightly capped, with gradual erosion of this cap into the
northwest CWA as surface dew points increase from the upper 40s
into the mid to upper 50s. The trajectory of the MCV closer to
the IL line with time combined with an only slightly less
favorable kinematic profile suggests thunderstorm activity could
survive as far south as a line from Rockford to Chicago in the
6-9pm window. The primary threat would be strong gusty winds,
perhaps locally damaging, owing to a significant DCAPE reservoir
nearing 1500 J/kg.
Kluber
&&
.DISCUSSION...
Issued at 313 PM CDT Wed Jun 12 2024
Through Thursday Night:
It will continue to be hot (but with thankfully tolerable dew
points/humidity levels) through the remainder of the day with
temperatures holding in the upper 80s to lower 90s until near
sunset. The lake breeze hugging the Illinois shore will get
pushed back offshore and result in rising temps there into this
evening.
Zonal northwest flow across the northern Plains has already
allowed a cluster of storms to get going. As these storms
potentially approach the far northwestern and far northern CWA
this evening, they will be in a weakening phase with isolated
showers and perhaps an embedded rumble of thunder. Another round
of storms will likely form later tonight and advance southeast
through MN and WI towards the northwestern and far northern CWA.
Dry low to mid-level air and a capping inversion across the
area will result in these storms weakening as they reach the
CWA.
Although unlikely, there is a chance that a few of these storms
both tonight and into early tomorrow morning could pose a
strong to locally severe wind threat if outflow is able to
maintain itself (best chance far NW CWA). Outflow may maintain
long enough for a breezy/variable wind shift as far southeast as
the Chicago metro around dawn. Kept PoPs in the 15-35% range
through the late morning with the best chance for showers and
storms around sunrise Thursday morning across the northwest 1/3
to 1/4 of the CWA.
Thursday afternoon, models are in good agreement that
southwesterly flow will allow moisture to build into the area
with dew points in the upper 60s (more aggressive models reach
the low 70s). With temperatures rising to around 90 degrees,
MLCAPE values in the 2000-3000 J/kg range are expected. A
surface cold front will be moving southeast towards the CWA
Thursday afternoon. Initially weak surface convergence, a cap,
and weak upper-level support will inhibit storms early in the
afternoon, however, as frontal convergence increases and a
modestly strengthened mid-level jet moves overhead, storms will
become more likely through the late afternoon.
The large CAPE values and 35-45 kts of shear will cause storms
to become supercellular in nature early on. Steep mid-level
lapse rates (7-8 degrees C/km) will present a threat for large
to locally destructive (2"+ diameter) hail with large DCAPE
values (>1000 J/kg) bringing a threat for strong to severe winds
(70-80 mph gusts possible). These storms will also pose a
localized flooding threat with heavy rainfall rates and PWATs
forecasted to be around or potentially over 2 inches. The threat
for severe weather has warranted a level 3 out of 5 risk for
the southwestern portion of the CWA (where confidence in higher
coverage of severe weather is highest) and a level 2 out of 5
risk for the remainder of the CWA from SPC.
Depending how the convection plays out Thursday morning could
impact how things unfold Thursday afternoon/evening. If
showers/storms hold on through the late morning across the area,
then temperatures will take longer to rebound and instability
will struggle to build early in the afternoon. This stability
would limit storm initiation chances until later Thursday
allowing the cold front to advance further south and thus moving
the highest threat for storms and severe weather further south
as well.
However, if showers dissipate before they reach the CWA, then
temperatures and instability will be able to build quickly and
storms may be able to form further north during the afternoon.
The 12Z HRRR seems to be playing more into this scenario, which
would be a "worst case" scenario for this setup, featuring
convective initiation and the anticipated level 3 type threats
currently farther southwest to likely include more of the
Chicago metro. This will be monitored closely.
Initial supercell development will likely grow upscale into
clusters or a more linear mode as the evening progresses. Once
the convection moves out of the CWA Thursday night, things will
quiet down into Friday morning.
Carothers/Castro
Friday through Wednesday:
An upper trough is expected to be pivoting through the Great
Lakes on Friday as broad upper-level ridging begins to establish
across the southwestern CONUS. The position of the upper trough
will advect in cooler air into the region resulting in warm but
comfortable temperatures and humidity levels for Friday and
Saturday with readings in the low to mid-80s. Though, daily lake
breezes will likely keep temperatures cooler (in the 70s) for
locations closer to Lake Michigan. Otherwise, dry conditions are
expected during this period courtesy of the aforementioned
ridge.
Heading into Sunday, the aforementioned ridge is forecast to
shift into the Mid-Atlantic region as a large upper-level trough
establishes over the northwest CONUS. As this occurs southwest
flow is expected to develop across the Midwest resulting in
increasing heat and humidity through at least the early portion
of next week. While guidance is in good agreement on the upper-
level pattern, there continues to be a lot of variance on how
far east the ridge will drift. Therefore, the exact magnitude of
heat remains uncertain but there is a notable signal amongst
both deterministic and ensemble guidance that high temperatures
in the 90s are likely with overnight lows possibly in the 70s
Sunday through Tuesday.
Additionally, there is also the threat for showers and
thunderstorms Sunday and Monday which may further add a failure
mode to the magnitude of the aforementioned heat. If the ridge
does establish further east then our area would be in the
favored area for shortwave troughs to pivot through and generate
at least scattered showers and thunderstorms and in turn keep
high temperatures lower. However, if the ridge remains further
west then showers and storms could miss our area resulting in
highs over performing from the current forecast and possibly
even nearing record values (upper 90s) particularly on Monday.
Given these uncertainties I have decided to maintain the 20%
POPs offered by the NBM for Sunday and Monday, but did lower
high temperatures into the low to mid-90s to account for the
cooler temperature potential with storms. Obviously this will be
a period to watch especially for those with heat sensitivities
so stay tuned.
Guidance is hinting that cold front may try to push through the
region during the Wednesday into Thursday timeframe which looks
to bring a better potential for showers and storms in addition
to a break from the heat. Though, details on when and where this
possible front will track remains uncertain at this range
therefore stay tuned.
Yack
&&
.AVIATION /00Z TAFS THROUGH 06Z FRIDAY/...
Issued at 706 PM CDT Wed Jun 12 2024
* Outflow boundary will lead to some squirrelly winds mid-late
evening, particularly ORD, RFD, DPA
* Small chance of SHRA/TSRA toward sunrise, better chance of
TSRA later Thursday afternoon
Some showers associated with an outflow boundary near RFD just
before 00z will continue to push east-southeastward toward ORD
and DPA this evening. Wind shift to northwest is likely with
this outflow with some brief gusts 20-30kt+ possible at ORD &
DPA. In the wake of this outflow, winds likely have a tendency
to flop around to northeast, with the lake possibly enhancing
that northeast wind potential. The northeast winds should veer
to southeast then back around to southwest after midnight. Lower
confidence in the wind shift reaching MDW and GYY, so will
monitor trends and adjust accordingly.
Will need to monitor storms over MN tonight, some potential for
this activity to dive southeast and affect the terminals around
sunrise Thursday. Low confidence in this scenario, so held off
in including it in the TAFs for now. Will allow overnight crew
to get a look at observational trends and make call on threat
with 06z and/or 09z TAFs
TSRA expected to light up on a cold front over northern IL
Thursday afternoon. The TSRA chances look to be mainly south of
RFD, but look to be close to ORD, DPA, and MDW, so maintained
the PROB30 for those terminals.
It does look likely that winds will settle in at northeasterly
Thursday evening, but confidence is low on timing.
- Izzi
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
Visit us at weather.gov/chicago
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
847 PM EDT Wed Jun 12 2024
.SYNOPSIS...
High pressure returns through Thursday leading to mainly dry
conditions. A cold front tracks through the area on Friday
leading to renewed shower and thunderstorm chances. High
pressure settles over the area this weekend with lower humidity.
Next week looks to become hot as a very strong upper ridge
builds towards the region.
&&
.NEAR TERM /THROUGH TONIGHT/...
Evening update: Skies are clearing out this evening across much
of the area as daytime mixing wanes. Some cumulus remains
across the Central Shenandoah Valley and Potomac Highlands.
Recent runs of the HRRR hint that a few showers may try to form
there this evening, so 20 PoPs have been maintained in those
locations through the evening hours. Elsewhere, dry conditions
are expected overnight. Previous discussion follows...
High pressure will remain overhead tonight, resulting in light
winds once again. This will make for yet another cool night for
mid-June standards. Upper 50s to low 60s are expected across
most areas, accompanied by some mid 60s in the usual warmer
pockets. Some patchy fog may materialize overnight for locations
west of I-95. However, its development could be hindered by any
cloud cover that lingers into the night. Best chance for fog
would likely be in the valleys and along the eastern slopes of
the Blue Ridge.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Thursday and Friday will bring about a big shift into a much
warmer weather pattern that likely continues into next week (see
long term below). Thursday should generally remain dry across
the area as high pressure finishes its traverse of the region
and moves offshore. This will begin to usher in warmer and more
moist air into the region. High temperatures Thursday are
expected to reach the mid to upper 80s (upper 70s to low 80s in
the mountains). Could see an isolated thunderstorm or two
along/west of the Blue Ridge over the higher terrain during the
afternoon. These will largely be driven by terrain circulations
and would likely be very short-lived given an overall lack of
CAPE and steep lapse rates.
Thursday night will be warmer and more humid than previous
nights. Low temperatures will be in the 60s for most, with some
patchy fog possible once again.
By Friday morning, a cold front tracking across the Lower Great
Lakes and Ohio Valley will set the stages for a possible round
of showers and thunderstorms. Before this occurs, Friday will
mark the hottest day of the week and perhaps the first crack at
a 95 degree day in 2024. Heat indices should be in the mid/upper
90s based on the latest dew point forecast. While falling short
of typical heat headlines, it is the first real bout of summertime
heat this season.
This heat will not come without its consequences however. Dew
points are forecast to be in the mid to upper 60s, which paired
with highs in the 90s will set the stage for thunderstorms in
the afternoon as the front approaches. Forecast vertical shear
values between 35-45 knots would be more than enough to support
organized convection. Some of these storms could become severe,
with damaging winds and large hail being the main threats. This
will all be very dependent on just how much instability is in
place. Some ensembles have us at around 1000-1500 J/kg, while
others struggle to get us above 500 J/kg of CAPE Friday
afternoon. The 12z run of the NAMNest was our first look at a
convective- allowing model (CAM) regarding this system. For what
it is worth, it depicts the highest threat in our northeast,
where the highest shear values are. However, it does struggle to
get us over 1000 J/kg of CAPE. Even with that being said, low-
level lapse rates are very impressive given the temperatures in
the 90s, so at least some marginal threat for damaging winds
exists. Of note though is the gap in convection over central VA.
One of the things I am a bit concerned about is westerly flow
in the mid-levels, which can introduce extra dry air and really
keep things from developing depending on the scenario. This is
of course just one model run, but it does at least address the
few concerns I have with this setup.
This activity should all exit into the Eastern Shore by late
Friday night. In the wake, prevailing northwesterly flow will
gradually usher in some drier air from central Canada. However,
temperatures do stay slightly above average with widespread 60s
expected (50s over the mountains).
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Dry conditions expected this weekend as surface ridge over the Mid-
Atlantic region pushes offshore by the end of this weekend. Upper
troughing early Saturday also quickly departs to the northeast.
Afternoon highs in the 80s each day, with Saturday night lows in the
upper 50s to low 60s.
An extended period of hot temperatures is expected next week as a
mid-level ridge sets up atop the Mid-Atlantic. At the surface, the
western extent of the Bermuda High builds in across the Carolinas
through at least the middle of next week, producing light southerly
flow over our area. Afternoon highs are forecast to reach the low to
mid 90s Monday, then mid to upper 90s Tuesday. Even though it is
beyond the current forecast, highs look to be in the mid to upper
90s each day through next week Friday. Increasing humidity likely
results in peak heat indices to around 100-105 each afternoon.
Overnight lows become milder as the week progresses, likely only
dropping to the low 70s Tuesday night.
A plume of deep tropical moisture advects north along the western
periphery of the surface and mid-level ridges. This yields high rain
chances across parts of the Deep South, and TN/OH River Valleys.
While most of the resulting convection remains west of our area,
some showers and thunderstorms are possible each afternoon along and
west of I-81.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
VFR conditions continue as high pressure builds into the region.
Some model guidance hints at some trapped moisture in the valleys
and along the eastern slopes of the Blue Ridge tonight. This
could perhaps bring the chance for some fog to CHO and MRB, so
have included that in the latest TAF. Winds will be very light
during this time and generally out of the south.
Southerly winds will begin to pick up in intensity on Thursday
by mid-late morning, with gusts in the 10-15 knot range by the
afternoon at all terminals. MTN could see some locally higher
gusts coming off the waters closer to 20 knots. There is a very
slight chance of a pop-up shower or storm near CHO Thursday
afternoon, but chances are around 20 percent at this time, so
left out of the TAF at this time.
The period heading into Friday afternoon into the evening will
likely lead to some restrictions given the threat for showers
and thunderstorms along an approaching cold front. Some of
these could become severe given the degree of warmth and
instability in the atmosphere. Winds quickly shift over to west-
northwesterly in the wake Friday night.
Dry and VFR conditions expected this weekend as light northerly
winds Saturday veer east Saturday night, then become southerly
Sunday afternoon.
&&
.MARINE...
Southerly winds remain sub-SCA in nature through tonight. This
will continue through Thursday morning as high pressure
gradually pushes offshore.
By Thursday afternoon, expect southerly channeling to really
pick up in intensity as high pressure moves offshore. Wind gusts
of up to 25 knots can be expected over the wide waters of the
Chesapeake Bay. An SCA was issued for this threat for all Bay
zones as well as the lower Potomac. Could see an expansion up
the Potomac potentially, but wasn`t confident enough at this
time to do so.
A cold front tracking across the area Friday afternoon/evening
will lead to the threat of strong to severe convection. This
could require some Special Marine Warnings for the area waterways.
Dry conditions expected this weekend as high pressure moves across
the region. Northerly channeling during the first half of Saturday
could produce SCA conditions in the open waters of the Chesapeake
Bay. Winds diminish Saturday night and become east. As surface high
pressure moves offshore Sunday, winds quickly turn southerly and
could gust to near-SCA levels Sunday evening.
&&
.CLIMATE...
High temperatures early next week. Below is a list of record high
temperatures for June 17th and 18th, the year the record
was set, and the current forecast high temperatures for those
days. Daily temperature records are currently only maintained at
DCA, IAD, BWI, and MRB. Others are shown for reference.
Monday Jun 17th
Climate Site Record High Forecast High
Washington-National (DCA) 99F (2022) 95F
Washington-Dulles (IAD) 96F (2022) 95F
Baltimore (BWI) 96F (2022+) 93F
Martinsburg (MRB) 98F (1939+) 93F
Charlottesville (CHO) 97F (2022) 94F
Annapolis (NAK) 96F (1939) 88F
Hagerstown (HGR) 96F (1952) 94F
Tuesday Jun 18th
Climate Site Record High Forecast High
Washington-National (DCA) 97F (1944) 96F
Washington-Dulles (IAD) 94F (2018+) 96F
Baltimore (BWI) 97F (1957+) 95F
Martinsburg (MRB) 99F (1943) 94F
Charlottesville (CHO) 96F (2014+) 95F
Annapolis (NAK) 96F (1957) 91F
Hagerstown (HGR) 95F (1957) 96F
+ indicates that value has been reached on multiple years, with
the year displayed being the most recent.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 2 PM Thursday to 5 AM EDT Friday for
ANZ530>534-537>543.
&&
$$
SYNOPSIS...CJL
NEAR TERM...CJL/KJP
SHORT TERM...CJL
LONG TERM...KRR
AVIATION...CJL/KRR
MARINE...CJL/KRR
CLIMATE...BRO/CJL
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
646 PM CDT Wed Jun 12 2024
.KEY MESSAGES...
- Warm and muggy today with strong to severe thunderstorms expected
this afternoon and evening. Large hail, damaging winds and a few
tornadoes are possible.
- Seasonable temperatures and dry weather are expected to end the
week with rain returning Saturday through early Sunday.
- Chances for precipitation along with warmer temperatures will
persist through early next week.&&
.DISCUSSION...
Issued at 636 PM CDT Wed Jun 12 2024
Showers and thunderstorms are continuing to make their way gradually
to the east this afternoon. Visible satellite showing much
clearer skies across much of western and northern MN as compared
to western WI. Thus, nudged down MaxT mainly across western WI
due to ongoing cloud cover. Agitated cu has already began to
redevelop across western MN and is expected to continue growing
in coverage through this afternoon. Across southern and
southwestern MN, observations sites are reporting breezy
conditions with gusts consisting of 20-30 mph. Even more
noticeable, is the strength of a SW`ly LLJ which is forcing
temperatures to rebound quickly into the upper 70s, upper 80s,
and even a couple of 90s. Meanwhile in the upper-levels, zonal
flow with a 120kt upper-level jetstreak extends from Montana all
the way to the Great Lakes region allowing for plenty of
divergence aloft. Closer to the surface, low pressure continues
to skirt across the MN/CAN border to which remains our primary
driver for additional rounds of convection this afternoon.
A cold front associated with the low pressure will proceed through
MN/WI as we progress through the remainder of this afternoon and
evening. Instability will increase across western MN early this
afternoon to values between 2000 to 3000 J/kg, and effective bulk
shear between 40-50 kts. Convective redevelopment is forecast
to begin as early as 3 PM but looking more likely near 5 PM
onward. As of now, all storm hazard types are in play although
the more favorable environment for tornadoes looks to be focused
more over north- central and northeastern MN given the 50-60kts
of effective shear. As development does occur, storm mode
should begin as supercellular providing the tornado/hail threats
and then congealing into QLCS line with potential bowing
segments providing the damaging wind threat. Although one
concern though we have is the results from recent CAMS. The HRRR
has been trending less convection coverage except for a few
isolated cells across western MN and central MN as well as
delaying more widespread redevelopment later and across
southeastern MN whereas the Nam3k favors a more widespread
QLCS.
Conditions will begin to improve as we move into Thursday and
Friday. The aforementioned low pressure will vacate east while
ridging builds over the western CONUS. Skies will clear out by
Thursday afternoon with forecasted highs around the 80 degree
mark and with Td`s in the 50s, conditions will likely not feel
as sticky as compared to today. This weekend into early next
week looks to be more wet than dry. A broad troughing pattern to
our west will lag in progression and eject multiple shortwaves
across the northern plains. As for QPF, the Weather Prediction
Center QPF forecast consists much of central MN and western WI
could see at least an 1" if not more of rainfall. Portions of
southeastern MN could sneak over the 2" mark by the start of
next week. Temperatures during this time will fluctuate between
the upper 70s to mid/upper-80s.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 636 PM CDT Wed Jun 12 2024
A few strong to severe storms have developed early this evening
in central Minnesota. They continue to move into a favorable
environment to sustain themselves. The storms will move eastward
over the next few hours, with RWF and MKT being the most likely
sites to miss the action. We will clear out shortly after
midnight in Wisconsin with light northwest winds.
KMSP...The window for storms looks to be between 03-05z, with
the possibility for development ahead of that timeframe, but
lesser confidence on that. These storms will likely lead to
MVFR/IFR conditions and could be severe.
/OUTLOOK FOR KMSP/
FRI...VFR. Wind VRBL at 5 kts.
SAT...RA/TSRA/MVFR likely, IFR possible. Wind SE 10-15 kts.
SUN...Mainly VFR. Slight chc TSRA/MVFR. Wind SW 10-15 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&
$$
DISCUSSION...Dunleavy
AVIATION...PV
Area Forecast Discussion
National Weather Service Marquette MI
729 PM EDT Wed Jun 12 2024
.KEY MESSAGES...
- Showers and thunderstorms expected (80% chance) between 9 pm and 3
am EDT tonight from west to east.
- There is a slight risk (category 2/5) of severe weather for the
western UP, with the main threats being large hail in excess of an
inch and damaging winds in excess of 60 mph. There is a marginal
risk (category 1/5) elsewhere, except for the far east.
- Gusty winds expected Thursday along with lingering showers and
thunderstorms.
- Dry Friday and early Saturday before the return of showers and
thunderstorms later in the weekend.
- Warmer than normal temperatures frequent the forecast, with some
areas approaching 90 for highs by next week.
&&
.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 244 PM EDT Wed Jun 12 2024
Early afternoon water vapor shows a couple of low-amplitude
shortwaves embedded in fast midlevel flow over the north-central
CONUS. The first is generating lift and a couple areas of showers
along the WI/MI border and western Lake Superior, while an MCS is
ongoing further south into the better instability over southern MN.
No lightning strikes have been noted directly upstream as of yet,
and with HRRR trending a bit drier/less convective for this
afternoon, convection seems to be low probability and thus potential
for thunder was capped at slight chance (<25%) for the remainder of
the afternoon.
Of greater concern is the late evening/overnight period tonight.
Convection is expected to develop rapidly over northern MN this
afternoon as steep (> 8C/km) lapse rates overspread the area. A
classic loaded gun sounding in this area should yield intense storms
assuming that forcing from the second aforementioned low-amplitude
wave and attendant low-level boundary is sufficient, which it should
be. The question for our area is to what extent these storms will
hold together as they cross Lake Superior. The steep midlevel lapse
rates should maintain MUCAPE of 1000-1500 J/kg across the western UP
as the storms arrive. Wind shear is quite impressive both in the low
levels, with a low-level jet of 30-40 kt overspreading the area, and
in terms of deep-layer bulk shear which will max out between 40-60
kt. CAMs vary in their depiction of the incoming convection, but the
HRRR has been relatively consistent in maintaining a broken line of
organized strong/severe storms across the lake. Large hail in excess
of an inch is a threat given the strong shear and steep midlevel
lapse rates, and damaging winds in excess of 60 mph are also a
threat despite the nocturnal period given the strong low-level wind
field and likely maintenance of a respectable low-level mixed layer
as well. SPC slight risk (level 2/5) in effect over the western
counties. Storms should weaken with eastward extent as they outrun
the better midlevel lapse rates and instability, but at least
isolated strong/severe storm threat exists across most of the UP as
SPC Marginal Risk (level 1/5) covers all areas except the eastern
quarter or so. Main timeframe for storms looks to be roughly 01-06Z
from west to east (9 pm-2 am EDT).
&&
.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
Issued at 335 PM EDT Wed Jun 12 2024
The active weather pattern across the CONUS continues through the
long-term forecast. The main features of note at 500mb are a trough
passing over Lake Superior Thursday and a deep cutoff low off the
coast of the Baja California, which will be the cause of active
weather over the weekend. Despite high pressure keeping a day of ,
the overall weather pattern through the long term is wetter than
normal and warmer than normal, with some of the hottest temperatures
of the year thus far forecast for Monday.
Thursday, the aforementioned trough will pass over the area. 850mb
cold advection and dry air behind the trough will allow for 20-30kt
winds to mix down to the surface. EFI shift of tails has backed off
somewhat but the Euro ensemble still calls for the potential of
gusts up to 35 mph. These gusts will almost certainly (90+%) not be
consistently high enough for an advisory but it will still be a
gusty day. CAMs call for some diurnal showers supported by post-
tropa clearing allowing for some radiational heating, but only
isolated thunderstorms are expected. Highs look to be in the 70s for
the most part except for the southern reaches of the UP reaching
into the 80s and some of the near-Lake Superior communities only
seeing highs in the 60s.
Once showers move out of the UP entirely Thursday evening, dry
weather will be over the UP through at least Saturday morning as
ridging aloft builds in and supports a near-1020mb high pressure
over the Upper Great Lakes. Friday will be a slightly cooler day
with highs only in the 60s to low 70s, but highs recover to the mid
70s for Saturday. RHs look to fall into the 40s and 30s, but with
very light winds, weather should be benign to end the work week and
begin the weekend.
Meanwhile, the deep cutoff low over the Pacific will deamplify and
shift northeast through the Rockies. The GEFS shows a low pressure
will develop in the Canadian Prairie, with the GEFS suggesting a
central pressure potentially below 990mb and perhaps into the 970s
mb over Manitoba by Sunday afternoon. With high pressure shifting to
the east, predominantly southerly low level flow will allow Gulf
moisture to surge north, as shown in the NAEFS vapor transport being
at the 90th percentile of climatology along with PWATs of near 1.5
inches. As the weakening trough approaches the Upper Great Lakes and
the cold front of the Canadian Low approaches, multiple lifting
mechanisms for showers and thunderstorms will be present, with PoPs
spreading west to east beginning Saturday PM. As the pattern is
complex, details on the strength and timing of storms is tough to
narrow down, so look for future forecast packages to gain clarity
there, but with the available moisture to work with, ensembles do
show about a 15% chance of daily precip totals to exceed an inch by
Sunday. This is a little lower than the last 24 hours of guidance,
but still enough to maintain some concern about weekend outdoor
plans that would be ruined by a downpour.
The gradual warmup continues into next week, with high 80s in the
forecast for Monday, with widespread low to mid 90s in the 75th
percentile of the NBM. PoPs remain in the rest of the long term
forecast as ensembles show a continued chaotic pattern through mid-
June. The general pattern looks to support ridging over the eastern
CONUS with a persistent surface high off the East Coast, which
should help create southerly to southwesterly flow to advect further
Gulf moisture north. As a result, the CPC outlooks the 8-14 day
period as being more likely to be warmer than normal and wetter than
normal.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 729 PM EDT Wed Jun 12 2024
Upstream thunderstorms moving into northeastern Minnesota and
western Lake Superior will continue pressing east-southeast this
evening, bringing thunderstorms, potentially strong to severe, to
KCMX and KIWD into tonight. Guidance suggests upscale growth and
eventual storm mode becoming linear as it moves across Lake
Superior, and we`re already seeing this transformation upstream.
This suggests strong winds, in addition to the hail potential,
should be considered. Depending on how well these handle the lake
transit, these strong winds may be realized at KSAW as well.
In the wake of the storms, low level moisture will support MVFR
ceilings at KCMX and potentially some fog. After the sun rises,
expect improving ceilings to VFR at all sites and daytime mixing to
support gusty conditions. Current tafs are for 20-30kt westerlies,
but some guidance does suggest mixing to support upwards of 40kts in
some areas by afternoon Thursday.
&&
.MARINE...
Issued at 335 PM EDT Wed Jun 12 2024
This evening, strong to severe storms are expected to be over the
western half of the lake as storms come off of the MN Arrowhead and
reach the western UP. Otherwise, southerly winds will broadly remain
below 20 kt. Behind a cold front driving through Thursday, cold
advection will drive gusty winds aloft to the surface, with westerly
to northwesterly wind gusts of around 25 knots expected on Thursday.
High pressure building over the Upper Great Lakes into the weekend
will keep wind gusts below 20 kt Friday through Sunday morning, when
a cold front will bring a return of thunderstorm chances. Waves will
largely be below 4 ft until Sunday when waves along the US/Canada
border on Lake Superior will grow to 4-5 ft.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Thompson
LONG TERM...GS
AVIATION...JTP
MARINE...GS
Area Forecast Discussion...UPDATED
National Weather Service Nashville TN
900 PM CDT Wed Jun 12 2024
...New UPDATE...
.UPDATE...
Issued at 900 PM CDT Wed Jun 12 2024
Tweaked hourly temperature, dewpoint, sky condition, and wind
direction/wind speed grids blending them with associated
previously forecasted hourly late evening gridded values.
Per analysis of current regional satellite imagery and latest
HRRR sky cover forecast through tonight, slightly decreased cloud
coverage from generally partly cloudy skies to mostly clear skies
remainder of evening hours tonight. Current regional temperature
trends in line with forecasted overnight lows. KOHX 13/00Z Sounding
showing despite warmup today, PWAT values are still only 0.77 inch
which is in the 10 percentile range for PWAT values for today with
riding influences surface and aloft prevailing. Remainder of
forecast continues to be on track.
&&
.SHORT TERM...
(Rest of today through Thursday)
Issued at 1026 AM CDT Wed Jun 12 2024
A surface ridge is aligned just south of the Ohio Valley this
morning, leaving Middle Tennessee with a dry, stable atmosphere.
The ridge will gradually slide across the region during the next
couple of days and we can expect summer-like heat to build over
the mid state as a result.
&&
.LONG TERM...
(Thursday Night through next Wednesday)
Issued at 1026 AM CDT Wed Jun 12 2024
The forecast is rain-free through Sunday night. Of particular note
is Sunday, when afternoon temperatures are expected to top out
near 100 degrees, but we do expect enough moisture advection to
lead to additional cloudiness and low POP`s beginning on Monday,
and also slightly cooler temperatures. Perhaps "not as hot" would
be more accurate, as the 6-10 day and 8-14 outlooks continue to
favor above normal temperatures for Middle Tennessee. QPF totals
for days 6-8 (nothing prior to day 6) are coming in under 1/4"
across most of the mid state. So the rainy pattern that persisted
throughout May and the first week of June has definitely shifted.
&&
.AVIATION...
(00Z TAFS)
Issued at 622 PM CDT Wed Jun 12 2024
VFR conditions continue this taf cycle. Winds are light and
variable. IFR to LIFR fog will be possible overnight at SRB. Other
areas should remain fog-free as the air is still quite dry.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 61 92 67 94 / 0 0 0 0
Clarksville 58 88 64 91 / 0 0 0 10
Crossville 59 85 64 87 / 0 10 0 0
Columbia 59 92 65 94 / 0 0 0 0
Cookeville 60 87 65 89 / 0 0 0 0
Jamestown 59 86 65 88 / 0 0 0 10
Lawrenceburg 60 90 65 93 / 0 0 0 0
Murfreesboro 60 92 66 94 / 0 0 0 0
Waverly 58 89 64 92 / 0 0 0 0
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE.......JB Wright
SHORT TERM...Rose
LONG TERM....Rose
AVIATION.....Baggett