Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/11/21
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
805 PM CDT Thu Jun 10 2021
.UPDATE...
Issued at 803 PM CDT Thu Jun 10 2021
Heat indices will continue to fall this evening, therefore allowed
the Heat Advisory to expire. No changes made to winds or
temperatures at this time. Things still look on track for a line
of thunderstorms to track across the CWA overnight, with strong
winds expected to be the main threat.
&&
.SHORT TERM...(This Evening through Friday Night)
Issued at 311 PM CDT Thu Jun 10 2021
An active overnight is expected. A decent looking wave on water
vapor imagery is lifting northeast through the basin this afternoon.
This system will continue to lift out to the northeast, and across
the western Dakotas late tonight/early Friday. Ahead of the system,
strong WAA/UVM will spread across the High Plains and into the
Dakotas overnight. Plenty of moisture/instability/shear should allow
for supercell development out west this evening, with forcing later
on leading to MCS development, especially around the Missouri
valley. The activity should ride the LLJ east overnight. All severe
modes appear possible out west this evening, with max STP values
progged over western ND. Later in the evening H5 winds increase
substantially over central/western SD as trof lifts into the region,
and this increase in winds aloft could lead to bowing line
segment(s) overnight with threat of strong winds. As the MCS moves
east it may outrun some of the upper support, and therefore the
strong wind threat is lower in the eastern CWA. Warm temps aloft may
also hinder things a bit in the east. That said, all CAMS are pretty
aggressive in moving an MCS over basically the entire CWA tonight,
with some rainfall amounts even possibly exceeding an inch. The last
couple runs of the HRRR have been the slowest, but not sure if that
makes it the model of choice or not. Any rain will be welcome.
Temperatures will cool down a bit for Friday, but then rebound again
for the weekend as upper ridge re-establishes itself. Friday will
also be much more comfortable as dry airmass advects into the
region behind departing frontal boundary.
.LONG TERM...(Saturday through Thursday)
Issued at 311 PM CDT Thu Jun 10 2021
To start the period, upper level ridging is in the process
of building over the area and remains the story through the entire
period. Supported by southerly flow at the surface, temperatures
will once again be quite toasty with highs reaching the 90s in most
locations every day. The occasional 100 degree temperature is not
out of the question either. The one fortunate thing is that unlike
this past week, moisture looks more limited and thus conditions will
be a little less stifling. Presently, mostly dry conditions are
expected through the forecast period. There are indications a
trough may begin to flatten the ridge towards the latter half of
next week potentially bringing relief to the region just beyond the
range of this forecast.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
Issued at 624 PM CDT Thu Jun 10 2021
Terminals KABR,KATY,KPIR,KMBG
VFR conditions will prevail across the area into the mid to late
evening hours. A line of thunderstorms will then track from west
to east across the area, exiting to the east early Friday morning.
Periods of MVFR cigs and vsbys and gusty winds are possible with
the storms. Once the line of storms exits, VFR conditions will
then prevail through the remainder of the day Friday.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...Parkin
SHORT TERM...TDK
LONG TERM...Telken
AVIATION...Parkin
Area Forecast Discussion
National Weather Service Binghamton NY
1015 PM EDT Thu Jun 10 2021
.SYNOPSIS...
Dry weather continues into tonight before a couple disturbances
bring in a chance for stray showers and some thunder Friday and
Saturday. Showers and storms become more likely for Sunday,
with more or less seasonable temperatures through the weekend.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
Mostly clear skies and comfortable temperatures are on tap for
tonight. With dew points in the lower 50s, temperatures will
fall to between 53 and 58 degrees along the NY/PA border.
Winds will remain light.
4 PM update...
Skies are staying sunny with light and variable winds behind
the front that has dropped down into southern PA. Temperatures
are peaking in the upper 70s and lower 80s across much of the
area, and in the mid 80s in the typically warmer valleys.
Mainly clear skies are expected overnight while winds stay
light, and this may help temperatures to quickly fall back as
far as the upper 40s in the higher terrain of the Catskills and
Poconos. Meanwhile, the rest of the area should bottom out in
the 50s.
Clouds will begin to move back in early Friday as the front
starts to lift northward once more. This may touch off a few
showers into the late morning, and showers and perhaps a few
rumbles of thunder will be possible through the afternoon as a
weak shortwave, currently analyzed over Lake Superior, passes
through the area. Given weak forcing and only a couple hundred
j/kg of CAPE at most, showers and storms should be pretty hit
and miss, and not very concerning. A general lack of moisture
present in soundings would also indicate fairly light
accumulations. A slightly cooler airmass and clouds should keep
highs in the 70`s to low 80`s for most of the region, but where
we can see rain showers, some cooler readings are possible.
A few stray rain showers are possible into Friday night, mainly
north of the NY/PA border ahead of yet another wave that will
drop through into Saturday. Otherwise, expect partly to mostly
cloudy skies while temperatures drop back once more into the
50s.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
For Saturday, an upper level wave will be dropping southeast
across NY and New England. This feature will push a weak front
southwest into central NY and northeast PA during the day.
Models indicate some moisture will linger at 925 mb and and even
850 mb especially into the afternoon. With northerly flow and
dry advection occurring during the maximum heating of the day,
we could see isolated showers popping up. NBM has a good handle.
Models show a capping inversion to preclude deep convection and
thunderstorms so have slight chance for showers mainly Saturday
afternoon.
Then for Saturday night, there will be lingering isolated showers in
the evening. Later Saturday night into the overnight hours Sunday
morning, another more defined upper level wave will approach and
bring more showers as cooling aloft combined with low-level moisture
advection increases instability. Have chance POPs between 06z and
12z Sunday.
For Sunday this wave is overhead and the models differ as to
how much instability is available for the afternoon heating. NAM
has much of northeast PA/central NY more stable suggesting
southeast low-level flow leads to more of a stable marine
layer advecting north. The GFS has more south to southwest flow
and lacks this more stable marine layer. Hence there is more
instability available on the GFS. For now, have chance for
thunderstorms with chance to likely POPs for showers as this
wave passes by. The GFS has decent mid-level winds 40-50 knots
at 500 mb or around 6 km. GFS CAPE which can be underdone is
around 500 to 750 J/kg. This suggests some potential for severe
weather Sunday. Since it is day 4 and there is a lot of
uncertainty related to the marine layer and instability Sunday,
we will hold off on any mention of severe weather. SPC has
predictability too low at Day 4 as well.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
For Sunday night, another upper level wave drops in quickly
behind the one on Sunday and continues the unsettled weather
pattern with more showers. There might be a few thunderstorms
Sunday evening with lingering instability.
Another upper level trough pushes through on Monday with a stronger
front. GFS CAPE is over 1000 J/kg along an axis ahead of front and
the shear is decent. Monday could be a severe weather event for our
area and we will have to keep an eye on this. Tuesday will see more
of the same with another stronger upper wave and more showers and
thunderstorms. Once this wave passes it looks like drier weather
will be in store for Wednesday and Thursday.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
VFR conditions are forecast to prevail through the taf period
areawide.
Expect SKC conditions overnight, with perhaps just a few mid or
high level clouds skirting northward at times.
Some model differences heading into Friday for the sky forecast.
The 3km NAM is more pessimistic, showing mid level clouds
quickly filling in from the south, and north by mid to late
morning, presumably aided by cumulus development. These clouds
would be in the 4-8k ft agl level. Meanwhile, the latest 21z
HRRR shows the strato-cu development remaining only across NE PA
through Friday morning (15z) with another area of sct to bkn
higher level clouds from SYR/RME northward. For the TAFs trended
toward a blended solution...but leaned a bit more optimistic
(HRRR solution).
For now, in the taf have bkn CIGs around 4k ft agl at AVP
Friday afternoon, but some of the guidance suggests this may be
an upper end MVFR cloud deck, between 2.5 to 3k ft agl. This
will be another trend to keep an eye on.
Another thing to watch will be the possibility for some
patchy fog/mist early Friday morning at ELM. Do not think the
fog would be nearly as widespread or thick as what was observed
early this morning. However, overnight lows dip down close to
the crossover temperature (low 50s) with clear skies, and light
winds. Therefore, cannot rule out localized shallow fog along
the river near sunrise.
Light and variable winds tonight turn over to the southeast at
around 5 to 8 kts Friday.
Outlook...
Friday Night...MVFR CIGs possible from an east-southeast flow
marine layer, then a cold front dropping south late at night.
Saturday...MVFR or lower CIG restrictions likely in the
morning, then gradually becoming VFR by afternoon (north to
south). Low chance for a few rain showers.
Sunday through Tuesday...Chance for afternoon SHRA/TSRA and
associated restrictions each day. Otherwise, mainly VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...HLC
NEAR TERM...DJP/HLC
SHORT TERM...DJN
LONG TERM...DJN
AVIATION...HLC/MJM
Area Forecast Discussion
National Weather Service Cheyenne WY
503 PM MDT Thu Jun 10 2021
.SHORT TERM...(Tonight - Saturday night)
Issued at 300 PM MDT Thu Jun 10 2021
High Wind Warnings remain on track this afternoon & tonight across
all of southeast Wyoming and the northern Nebraska Panhandle. Wind
gusts to 50+ MPH have been observed across much of Carbon & Albany
counties this afternoon w/ winds likely to increase further during
the next few hours post-fropa. 700-800 hpa flow increases markedly
to 55-65 knots over much of the CWA after 00z along with excellent
low-level gradients and intense downward omega comparable to major
bora events that typically occur in winter time. MAV/MET sustained
winds of 30-40 knots at several sites is a good indication of high
wind (50+ knot) potential and a variety of in-house guidance still
leads to exceptional confidence in the development of strong winds
over much of the area by early this evening. In the Neb Panhandle,
the higher terrain along the Pine Ridge will stand the best chance
to see locally higher gusts approach 70 MPH. No changes needed for
inherited High Wind Warnings. Winds should diminish for most areas
by early Friday AM.
A highly conditional threat for strong/severe thunderstorms exists
later this afternoon through this evening across our eastern zones
in the moist low-level environment east of the dryline. A strongly
unstable air mass is present in these areas with 3000-4000 J/kg of
MLCAPE alongside favorable effective bulk shear of 35-45 knots. As
such, any storms that develop in the next few hours could have the
potential to develop into significant supercells with large hail &
damaging winds the primary hazards. However, the HRRR has been the
most consistent high-resolution model with very little activity in
our CWA. NAM soundings suggest initially poor moisture quality and
a slight inversion aloft, which may suppress initiation until deep
layer forcing increases after 02z with the short wave & associated
cold front. Highest probability for severe storms today will be in
the northern Nebraska Panhandle around CDR/AIA. Slight possibility
that a couple of storms may develop southwest toward BFF, but this
would be heavily dependent on outflow boundaries.
Much cooler Friday in the post-frontal air mass. Highs will likely
be around 15 degrees cooler for most areas w/ little if any chance
for precipitation. Upper-level ridging builds back into the region
on Saturday w/ warm and dry conditions returning.
.LONG TERM...(Sunday - Wednesday)
Issued at 330 AM MDT Thu Jun 102021
A persistence forecast will be the theme for the long term as the
CWA will be dominated by a amplifying large scale ridge pattern.
The center of the 500mb ridge will retrograde west to the vicinity
of the Four Corners early next week. 700mb temperatures will range
from 18 to 20 degrees Celsius at this time, resulting in afternoon
highs in the 90s to near 100. Large scale subsidence and lack of
moisture will unfortunately preclude any mention of precipitation.
Lowest relative humidities (7 to 12 percent) will be west of the
Laramie Range where fuels will be drying out. Fortunately, wind
speeds will be below fire weather headline criteria.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 500 PM MDT Thu Jun 10 2021
VFR conditions likely through the forecast period for all
terminals. Main concerns for the forecast period exist with any
thunderstorm activity across the Nebraska Panhandle. Current HRRR
guidance has a primarily dry forecast across the Nebraska
Panhandle, with most of the precipitation in the northern boundary
of the CWA, and northward into South Dakota. Confidence has
remained low for any thunderstorm development across the Nebraska
terminals. However, with sufficient energy across the domain, any
atmospheric push could get convection started, just not seeing the
moisture required. As a result, went ahead and left VCTS wording
in the TAFs. Otherwise, gusty conditions will prevail as the front
pushes eastward through late tomorrow morning before calming down
to light and variable.
&&
.FIRE WEATHER...
Issued at 300 PM MDT Thu Jun 10 2021
Extremely critical fire weather conditions continue this afternoon
for areas along & west of the Laramie Range with RHs as low as 5 %
and wind gusts up to 60 MPH. Winds become more widespread tonight,
but RHs will begin to recover. Improving conditions are likely for
Friday in the post-frontal air mass with much cooler temperatures.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Warning until 6 AM MDT Friday for WYZ101-102-106>108-
116>119.
High Wind Warning until midnight MDT tonight for WYZ104-105-
109>111-113-115.
NE...High Wind Warning from 8 PM this evening to 6 AM MDT Friday for
NEZ002-003-095-096.
&&
$$
SHORT TERM...CLH
LONG TERM...MJ
AVIATION...MD
FIRE WEATHER...CLH
AREA FORECAST DISCUSSION
National Weather Service Sioux Falls SD
1031 PM CDT Thu Jun 10 2021
.SHORT TERM...(This Evening through Friday)
Issued at 305 PM CDT Thu Jun 10 2021
Early this afternoon, temperatures have risen to the lower to upper
90s across much of the region, with an axis of locally higher dew
points in the upper 60s to lower 70s and thus heat index readings
across south central SD. Quiet but hot weather is expected through
around midnight tonight as the region remains primarily influenced
by strong upper ridging and breezy southerly flow.
Late this afternoon through early evening, strong to severe
thunderstorms are expected to develop in the western Dakotas as
strong shortwave ejects from the Northern Rockies into North Dakota.
As a strong jet streak rounds the west side of the upper ridge over
the Central U.S. and the low level jet develops lee of the Rockies
through the evening, attention turns to storms tracking east with
cold pools conjoining and growing upscale into several complexes of
strong to severe thunderstorms. The latest HREF guidance still
favors the southernmost complex of storms reaching the MO River
Valley in south central South Dakota after midnight, likely not
until 07-09z. With the majority of severe wx threat occurring
between 2am and 8am, it is important for folks to have a means of
receiving severe wx warnings overnight tonight.
Initially, storms will encounter an environment ripe for severe
weather across south central SD with potential for for large hail up
to quarter size, brief tornadoes, and damaging winds potential 80+
mph west of the James River basin. This occurs amidst an axis of 2.5-
4.0 kJ/kg MLCAPE, mid level lapse rates around 8C/km, 30-40 kts 0-
3km shear oriented mostly normal to the line, and DCAPE upwards of
2000 J/kg.
Model soundings show a mainly west or southwest profile above the
boundary layer and nocturnal decoupling inducing a stable near sfc
layer in the early morning hours. This combined with the strong LLJ
(around 50 kts), a NW-oriented CLMW, and forcing for ascent along a
frontal boundary/upper trough axis supports a transition to a mainly
damaging wind threat as the complex tracks east of the James River
early in the morning. HREF updraft helicity tracks and most model
reflectivity fields show the main threat area shifting to the
southern portion of the line south of I-90 in the early morning
hours. This southern area is more likely to bow southward and turn
more ESE creating a more widespread damaging wind threat south of
the I-90 corridor, fed highly downstream unstable air from the LLJ.
Uncertainty remains regarding how far east the complex will progress
before the southern portion turns more southerly and becomes more of
a widespread wind threat - as early as 07z or as late as 12z.
Further north along and north of I-90, severe weather threat will
start to wane as sunrise approaches and storms approach the I-29
corridor, but there is still potential for scattered up to 70 mph
wind gusts and up to quarter sized hail with the complex. This will
likely affect areas along I-29 close to when the morning commute
occurs. Further east in southwest MN and northwest IA, storms
probably won`t move in until after sunrise with isolated hail and
wind threat persisting (highest along/south of the Hwy 20 corridor)
through the morning.
Tonight`s system is not expected to be a major rain-producer, though
it`ll be the most rain we`ve had here in a while. The best chance of
an inch or more of rain is for areas west of I-29 where
thunderstorms will be more numerous overnight. Areas along and east
of I-29, especially further north, will likely see a half inch of
rain or less. After storms move out of the area Friday morning, the
18z HRRR does depict potential for a wake low or locally higher
areas of winds, so this threat will bear watching through mid
morning as well.
Overall Friday should be a milder and drier yet breezy day behind
the passing front. There is some uncertainty in high temperatures,
depending how quickly clouds can clear out, but generally expect
temperatures to only rise into the 80s with dew points at a more
pleasant 45-60 degrees. Northwest winds will be breezy and gusty
early in the day, immediately behind the front, and weaken as sfc
high pressure builds in.
.LONG TERM...(Friday Night through Thursday)
Issued at 305 PM CDT Thu Jun 10 2021
After temperatures take a brief dip with the departing disturbance
on Friday, highs will once again rise into the 80s and 90s for
Saturday and beyond as southern stream upper ridging takes hold of
the Central U.S. again. While humidity levels will stay milder than
they`ve been over the last few days as Gulf moisture remains mostly
blocked from the region, hot and dry weather remains the theme
through at least the first half of next week. Cannot rule out a
period of spotty rain chances early in the week if a shortwave can
survive northwest flow aloft over the ridging, but it`s more likely
that any decent rains will hold off until late week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1027 PM CDT Thu Jun 10 2021
A line of thunderstorms is expected to move into central SD by
07Z, then track into the the KHON vicinity around 09Z, and KFSD
and KSUX around 11-12Z. These storms may have damaging winds in
excess of 40 kts as they move through. Showers and storms will
push out of the area by late morning on Friday. Winds will
transition from southerly to northwesterly by Friday morning,
gusting 20 to 25 kts through the afternoon. Winds will diminish on
Friday evening.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...BP
LONG TERM...BP
AVIATION...JM
Area Forecast Discussion
National Weather Service Lincoln IL
823 PM CDT Thu Jun 10 2021
.SYNOPSIS...
Issued at 232 PM CDT Thu Jun 10 2021
While primarily dry conditions will prevail, there will be at
least a chance of showers and storms each afternoon and evening
through Saturday. Meanwhile, temperatures will warm into the lower
90s Friday and Saturday with heat indices in the 95-100 degree
range.
&&
.UPDATE...
Issued at 823 PM CDT Thu Jun 10 2021
Mostly quiet conditions expected to start the night as flow aloft
remains weak. Patchy fog remains possible late tonight across
eastern and southeast IL where the lightest winds are expected in
the vicinity of a trough axis. However, anywhere the boundary layer
remains moist from earlier precipitation could develop brief periods
of patchy fog further to the north and west. Mid-level ridging moves
overhead going into Friday with temperatures expected to climb into
the upper 80s to low 90s once again.
&&
.SHORT TERM...(This evening through Friday)
ISSUED AT 232 PM CDT Thu Jun 10 2021
Hot and humid conditions are in place across much of the Midwest.
A surface trough is in place along the Ohio River Valley this
afternoon which is supporting scattered showers and thunderstorms
across the area. Some of this convection extends into portions of
central and southeast Illinois but the greatest coverage of precip
is expected to stay in the vicinity of the I-70 corridor and
areas south. Dew points near 70F and temperatures well into the
80s are contributing to moderately strong instability with the
latest RAP showing MLCAPE values peaking generally between
1500-2000 J/kg. Flow aloft remains very weak which is resulting in
slow storm motions and an overall low threat for severe weather
given the weak deep layer shear, though couldn`t rule out a storm
pulsing to severe limits briefly given the amount of instability.
Cloud bearing mean flow remains fairly weak as well, generally out
of the north at 5-10 kts this afternoon, so any stronger storms
could produce locally heavy rain as they slowly move over an area.
Coverage of showers and storms will diminish after sunset with
loss of daytime heating. Cumulus should dissipate as well leaving
mostly sunny skies and continued muggy conditions. Patchy fog
development is possible across the area, but especially in the
I-70 corridor where winds are lightest near the trough axis.
500mb ridge will begin to shift across the Mississippi River
Valley tonight with subsidence helping to provide mostly sunny
skies Friday and temperatures warming into the lower 90s. Heat
index values will top out in the 95-100F range Friday.
.LONG TERM...(Friday night through Thursday)
ISSUED AT 232 PM CDT Thu Jun 10 2021
Forecast details are still a bit fuzzy over the weekend though hot
and humid conditions should be the primary story. Weak low
pressure is expected to move east across the Canadian Prairies
Friday through the weekend with the tail end of a cold front
pushing across portions of the plains and Midwest where it will
tap into moderately strong to strong instability along with some
accompanying higher deep layer shear values sufficient to support
more organized thunderstorm evolution well to our west. Saturday
will be the best chance to see any precip locally as the synoptic
trough moves through the region, but mesoscale details may end up
telling a different story. Once the trough passes through though,
precip chances will diminish later Saturday into Sunday. Expect
afternoon highs near 90F or into the lower 90s this weekend.
Most of the upcoming week looks to be dry across central Illinois.
The local area will remain on the eastern periphery of a strong
upper ridge centered over the Great Plain. Meanwhile, an
expansive surface high will build from the Canadian Prairies to
the Midwest through the week providing some break from the muggy
conditions with dew points generally staying in the 50s despite
temperatures continuing to run slightly above normal.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 624 PM CDT Thu Jun 10 2021
Widely scattered showers and storms will come to an end here shortly
after 00Z. Winds become light and variable overnight before taking
on a more northwest direction on Friday. Patchy fog is possible
overnight from 09Z through about sunrise. The latest guidance
continues to keep the majority of fog development over eastern and
southeast IL. Cannot rule out a brief period of fog at CMI or DEC,
though confidence remains too low to introduce into TAF. Will re-
evaluate for 06Z issuance.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NMB
SYNOPSIS...Deubelbeiss
SHORT TERM...Deubelbeiss
LONG TERM...Deubelbeiss
AVIATION...NMB
Area Forecast Discussion
National Weather Service Louisville KY
734 PM EDT Thu Jun 10 2021
...Updated Aviation Discussion...
.Mesoscale Update...
Issued at 615 PM EDT Thu Jun 10 2021
Have been watching scattered cells over central KY and southern IN
this afternoon, which have so far stayed well north of the
Cumberland Pkwy. Mesoanalysis has roughly 2000-2500 J/kg of SBCAPE
with no effective shear to speak of. Moderate CAPE has (and will
continue for the next few hours) allowed for decent updrafts and
relatively cold cloud tops. However, with weaker flow aloft and no
wind shear to support organization, cells have remained rather
disorganized and slow moving. PWATs are in the 1.9-2.1" range, and
combined with slow moving cells, has led to some training and heavy
downpours, resulting in isolated areas meeting or slightly exceeding
3 or 6 hour FFG. Primary hazard for this evening will be localized
flooding issues, so will be keeping eyes on radar and MRMS flash
flood guidance products.
&&
.Short Term...(This evening through Friday)
Issued at 246 PM EDT Thu Jun 10 2021
Persistent pattern continues as the upper level low has now become
absorbed into the upper flow with troughing extending SSE across the
OH Valley. Surface analysis places a center of low pressure along
the OH River in western KY with troughing extending NE across
central KY and southern Indiana and 70 degree isodrosotherm
encompassing all of the CWA. Radar is currently showing scattered
showers and a few isolated thunderstorms across the area as KY
Mesonet shows temperatures in the upper 70s to mid 80s.
SPC Mesoanalysis shows a bullseye of surface convergence near the
low center in western KY and extending NE along the OH river
coincident with SBCAPE maxima of 2000 J/kg. This is where the best
chances of thunderstorms will be, though RAP model soundings have
been advertising a subtle warm nose around 700mb that could inhibit
robust thunderstorm development through the afternoon. Several
observations so far have reported 1/4SM within heavy rain showers,
so main threat continues to be brief torrential rainfall with flash
flooding potential. General flow appears to be progressive across
most of KY with storm motion approximately 260/20kt, but in southern
Indiana mean flow is noticeably weaker where radar shows storm
motions closer to 10kts. Southern Indiana is also where flash flood
guidance is lowest due to consecutive days of showers, so will keep
a close eye on radar and flood potential throughout this afternoon
and into the evening hours.
Tonight, expect to see convective activity wane as we lose surface
heating. Some clearing across the area will lead to low stratus and
fog development by early morning and persist through mid morning.
Low temperatures Friday morning will range between 66 and 71.
As the surface low pushes ENE across the OH Valley tonight through
tomorrow afternoon, the region will remain within a sultry
environment with surface dew points in the low 70s and PWATs
remaining around 1.80 inches. Expect another day of mainly diurnally
driven showers and isolated thunderstorms with high temps in the mid
80s.
.Long Term...(Friday night through Thursday)
Issued at 218 PM EDT Thu Jun 10 2021
The weekend:
A weak cold front will approach the region Saturday and push through
the area late Saturday night into early Sunday. With the warm, humid
air mass still in place ahead of this feature, scattered showers and
thunderstorms can be expected...particularly Saturday afternoon and
evening when instability peaks around 2000 J/kg SBCAPE with 20-25kt
bulk shear. High temperatures will be from the mid 80s to around 90.
In the humidity ahead of the front Saturday afternoon heat index
readings will climb into the middle 90s west of the Blue Grass.
Next week:
Overall, next week looks primarily dry as a couple of surface ridges
slide southward through the area. One possible interruption will be
the trough located between those two ridges. The ECMWF brings this
feature through Monday night but the operational GFS waits until
Tuesday and brings it through at a time of better instability. As a
result, the GFS develops a significant band of showers and storms in
the Ohio and Tennessee Valleys coincident with it. However, the
ECMWF and CMC so far have remained dry. Most members of the ENS EC
are dry, as are almost all members of the GEFS. Given that the
operational GFS is an outlier at this time, will stick with a dry
forecast for now. However this will be something to watch -- the GFS
has had good run-to-run consistency over its past four runs,
generating precipitation Tuesday.
Unfortunately the Desert Southwest will bake next week as a powerful
upper ridge sets up over the Four Corners. However, for us we`ll be
watching a corresponding upper trough dropping from southeast Canada
into the eastern United States, keeping our temperatures in check.
Highs for us each day should generally be in the 80s (can`t rule out
a few spots touching 90 on Monday...and the Blue Grass will peak
in the 70s on Wednesday).
&&
.Aviation...(00Z TAF Issuance)
Issued at 733 PM EDT Thu Jun 10 2021
IMPACTS: Scattered showers and storms ending this evening. MVFR
conditions likley overnight with patchy dense fog.
DISCUSSION: Convection has continued to diminish in intensity this
evening with the loss of heating. Expect scattered convection to
continue to wind down as the evening wears on. Overnight, clouds
and low-level moisture will remain and cigs should build downward
with time. MVFR fog is possible at the terminals, though KHNB may
drop down below IFR overnight. The lowest cigs/vsbys look to be
between 11/08-13Z. Low clouds are expected to linger into Friday
morning with cigs returning to VFR by mid-late morning Friday.
CONFIDENCE: Medium on all elements.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Mesoscale...CJP
Short Term...CG
Long Term....13
Aviation.....MJ
Area Forecast Discussion
National Weather Service Memphis TN
919 PM CDT Thu Jun 10 2021
.DISCUSSION...
An upper low continues to linger over the region. Scattered
showers and thunderstorms have developed across northern parts of
the Mid-South where the greatest instability is located. Latest
CAMs have this activity shifting east and percolating over West
TN overnight mainly near the TN River valley. A few strong storms
with locally heavy rain are possible.
The main question is what will happen across North MS. The setup
is similar to the last few nights with a stable low level airmass
across the region attm. Later tonight low level flow increases
slightly to 15-18 kts from the west which will feed moist and
unstable air over that stable low level airmass resulting in more
showers and thunderstorms. Latest CAMs are not nearly as
aggressive as the past few nights so perhaps with the upper trough
shifting slightly east, the low level flow a touch weaker, PWATs
a touch lower, the setup is not quite as good. Nevertheless,
given the threat for at least some additional rainfall on
saturated soils will leave the flash flood watch as is for now.
SJM
&&
PREV DISCUSSION... /issued 331 PM CDT Thu Jun 10 2021/
Latest KNQA radar shows scattered storms across northeast
Arkansas, the Missouri Bootheel and West Tennessee. North
Mississippi is currently getting a much needed break from activity
this afternoon, however, impacts from days of flash flooding are
being felt across the area. Since midnight portions of this area
has seen roughly 6 to 10 inches of rainfall. Aside from what is
occurring across the northern portion of the CWA, additional
storms are developing across Central Arkansas and Central
Mississippi this afternoon. Latest runs of the HRRR and 3kNAM do
indicate the possibility of additional redevelopment of storms
across portions of North Mississippi and East Arkansas tonight
into Friday. Though coverage is not anticipated to be as
widespread any additional rainfall will certainly pose a threat
given heavily saturated soils. Given the possibility of
redevelopment, the Flash Flood Watch was extended through Friday
evening.
Heat could be another potential issue heading into Friday and
Saturday. Despite temperatures in the upper 80s, heat indices will
could rise to near 100F as a result of evapotranspiration. This
will need to be watched closely.
Latest model guidance indicates the upper trough will finally lift
out of the area on Friday. At that point, northwest flow will set
up across the Mid- South as the area will be in between an upper
trough across the East CONUS and a building upper ridge to the
West. Another shortwave will rotate around the upper ridge
prompting additional showers and storms on Saturday. This will be
followed by a weak cold front that is expected to move through on
Sunday.
There is a light at the end of the tunnel...it appears upper
ridging will start to build into the region on Monday and remain
in place through at least mid-week next week. Beyond that point,
guidance start to diverge and differs on how to handle an upper
low across the northeast.
17
&&
.AVIATION...
00Z TAFs
MVFR ceilings have already begun to spread back in at MEM/MKL
over the past couple of hours. Current trends suggest MVFR
ceilings should overspread TAF sites again tonight with potential
development of IFR ceilings overnight towards sunrise Friday.
Conditions will gradually improve to MVFR/VFR throughout the day.
VCSH/VCTS possible at JBR/MKL through mid-evening with VCSH
possible overnight at TUP. VCTS possible Friday afternoon at sites during
peak heating.
CJC
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...Flash Flood Watch through Friday evening for Lee AR-Phillips.
MO...None.
MS...Flash Flood Watch through Friday evening for Alcorn-Benton MS-
Calhoun-Chickasaw-Coahoma-DeSoto-Itawamba-Lafayette-Lee MS-
Marshall-Monroe-Panola-Pontotoc-Prentiss-Quitman-
Tallahatchie-Tate-Tippah-Tishomingo-Tunica-Union-Yalobusha.
TN...None.
&&
$$
Area Forecast Discussion
National Weather Service Marquette MI
809 PM EDT Thu Jun 10 2021
.SHORT TERM...(This evening through Friday)
Issued at 249 PM EDT THU JUN 10 2021
Showers and thunderstorms moved through the west and Lake Superior
this morning ahead of a surface cold front moving into the western
part of Lake Superior. Cloud cover associated with these really
delayed warming through the day. By 10am, ob sites in the Keweenaw
were still in the low 60s and the west was only in the mid 70s. Fog
that developed after the rain moved through certainly helped keep
temps low, particularly in the Keweenaw. In areas where shower and
thunderstorm activity has been absent, temps warmed up into the mid-
upper 70s to near 80F in some interior locations this morning.
Closer to Lake Michigan, temps so far have topped out near 70F.
This afternoon, models are queuing in on another round of convective
activity across the west half. The driver appears to be an upper
level shortwave diving southeast across the lake and into the west.
There are some differences among the guidance, and likely some
exaggeration by some, mainly the NAM, but generally expecting 1-2000
j/kg of MLCAPE with minimal CIN to allow for activity to start
firing close to 18z. Limitations on sustaining updrafts will be weak
deep shear, but low level shear of 20-30 kts could sustain some
thunderstorms, particularly if the lake breeze is in the vicinity.
CAPE profiles, DCAPE and steep low-level lapse rates suggest severe
wind and hail could be possible.
Convection should dissipate overnight. However, recent HRRR runs try
to maintain activity a little longer over eastern Lake Superior,
which would then move into the east. Persistent surface moisture and
patchy dense fog should help to maintain above normal lows,
particularly in areas where it does end up raining. Overall,
expecting lows to bottom out near 60F with some mid 50s possible in
the mid 50s.
Upper level ridging will persist over the western half of our
forecast area, forcing an upstream low to drift north from the
Dakotas into Manitoba. Surface front tied to this low is expected to
move into the western half of our forecast area by afternoon, helping
to once again set the stage for another round of showers and
thunderstorms by afternoon. Highs tomorrow look to be in the
80s inland and high 60s to mid 70s by the lakeshores.
.LONG TERM...(Friday night through Thursday)
Issued at 358 PM EDT THU JUN 10 2021
A cold front is expected to move through the U.P. Friday night and
Saturday. Some thunderstorms and showers are expected in the west
early Friday night with this cold front, but as the night continues,
expect thunderstorm activity to diminish; by Saturday morning, only
rain showers are expected to continue across the eastern half of
Upper Michigan. After the cold front moves through on Saturday,
there may be a chance for some light rain Sunday evening. Otherwise,
no additional precipitation is expected until next Thursday, when
some models hint at a possible cold front moving through the area.
Expect cooler and drier conditions early next week, with
temperatures being much closer to climatologically normal. However,
by the end of the extended period, temperatures across the area
could again become well above average.
As a low pressure continues to lift northeast in Canada, a cold
front is expected to push through the U.P. Friday night into
Saturday. This front should bring some much needed rainfall across
the area. There`s a chance for some thunderstorms in the western
half of the CWA early Friday night as the cold front is progging
through the area. However, as the front weakens and as CAPE
decreases (due to lack of diurnal heating), thunderstorm chances
should diminish the further east the front travels. No more than a
stray thunderstorm should happen by Saturday morning when the front
is making its way through eastern Upper Michigan. No severe weather
is expected with the thunderstorms over the west early Friday
evening, although a wind threat could be possible if there is enough
organization of the convection to form a line of thunderstorms (like
a QLCS). Bulk shear, though, doesn`t look all that impressive, so,
again, it`s not expected. As for flash flooding, it is not expected
either at the moment.
Once the cold front moves through, there may be a string of light
showers and a thunderstorm or two that moves over the area. However,
did not increase the pops or cloud cover, as I was 50/50 on putting
slight chances in the grids, and I didn`t hear back from my
neighbors. Also, chances are above 10%, so I feel confident enough
to leave it in for now, but could see these chances increasing as we
approach next week.
Otherwise, dry and cooler weather is expected as a low sits over the
East and a ridge builds over the Plains. Eventually, this ridge
should build over us during the middle of next week. This should
progressively increase temperatures to what we`ve been seeing
recently throughout the week, with the warmest day Thursday as the
ridge moves over us. This would put us in the warm sector ahead of
an upcoming cold front, which should probably arrive Friday
(although there is a chance it could arrive Thursday or Thursday
night instead).
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 807 PM EDT THU JUN 10 2021
Some additional showers and possibly a thunderstorms may brush
locations near KCMX and KSAW this evening. Otherwise, with
lingering low level moisture under a developing inversion, expect
areas of fog to develop along with low ceilings. Guidance brings
all three terminals down to LIFR conditions before conditions
slowly improve through the day tomorrow.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 249 PM EDT THU JUN 10 2021
Winds are expected to be 20 knots or less for most of the forecast
period. As a cold front passes through the lake today, thunderstorms
are expected to develop. Some could product some gusty winds and
hail. After the front, lingering moisture atop the cool lake will
create pockets of dense fog. Areas of fog are expected at times
through the weekend as well, particularly in areas that have
experienced any rain fall.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JP
LONG TERM...TAP
AVIATION...JLB
MARINE...JP
...Updated Aviation Forecast Discussion...
.DISCUSSION...
Issued at 413 PM CDT Thu Jun 10 2021
After a stretch of monotonously quiet weather that lead to the
expansion of drought conditions across the area, the forecast is
heating up. Today is the warmest day of 2021 so far for most
locations with numbers at 20Z generally in the mid-90s. Heat
indices have sneaked up to 100 in spots. A heat advisory
continues through 8pm for far eastern and far northeastern
Nebraska which includes the metros of Omaha and Lincoln. These
last two areas deal with the urban heat island effect which can
leave downtown temperatures hotter than surrounding neighborhoods
with the asphalt and steel holding the heat longer into the night.
Temps tonight will generally hold in the 70s as a mesoscale
convective system approaches from the west. As of 21Z, convective
initiation is just beginning in eastern Montana ahead of a
negatively tilted shortwave trof. This is where the NAM predicted
CI. The NAM also suggests upscale growth quicker than the HRRR...
leading to a faster arrival time of about 08Z in the NW corner of
the CWA and 11Z for Lincoln and Omaha. The HRRR is about three
hours later. I`ve split the difference with the knowledge that
CAMs sometimes under estimate the forward pace of the cold pool.
Regardless of arrival time, the tornado and hail threat will be
greatest well west of our area earlier in the evening and by the
time the system works into the more stable (less unstable?)
environment of eastern Nebraska, the threat will be damaging wind
gusts. Still, 1500 J/kg of CAPE overnight is nothing to sneeze at.
A half of a much needed inch of rain is possible with localized
areas maybe getting the whole inch.
Models are in general agreement that the system tends to weaken
through the early morning hours, reducing the wind threat for
areas south of interstate 80. However, any ongoing storms may find
themselves in a moisture-rich and rapidly heating environment
where Missouri / Iowa / Nebraska and Kansas come to meet. T-storm
mode may revert to supercellular growth as the sun grows higher in
the sky on Friday. This would bring another severe threat for
Friday afternoon for the extreme SE corner of the CWA or points SE
of there.
Also tedious were the continued SSE winds that have helped keep
the temps high all week. They`ll finally turn to the NW on Friday
behind the departing system. A short-lived break from the
oppressive heat will leave highs ranging from low 80s along SD to
low 90s closer to Missouri. Dewpoints fall into the 50s through
the day as the cooler air is markedly drier, too. Occasional gusts
up to 30 mph are possible north and west of Lincoln and Norfolk
mid-day Friday as the new airmass works into the area. Friday
night should be pleasant with relaxing winds and lows near 60.
Highs begin climbing again with the redevelopment of the mid-level
ridge on Saturday. It grows increasingly amplified through the
weekend. By Monday, mid-90s find their way back onto our digital
thermometers. All guidance shows a cold front working through the
area Monday evening tied to a shortwave rounding the Hudson Bay.
At this point, only the GFS produces precip and perhaps severe
weather. Have kept the forecast dry for now, but will continue to
monitor.
Overall, the forecast remains warm and mostly dry. Here`s to
hoping that tonight`s convection brings more rain than wind as
precip chances are anemic for the remainder of the forecast.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 616 PM CDT Thu Jun 10 2021
The 00z TAF period is set to kick off quietly with cumulus at
around FL070 and some cirrus even higher. The main focus of the
TAF period will continue to be the morning thunderstorms Friday.
Short-term model guidance differ by up to 2 hours in terms of the
onset of the storm complex, but nonetheless thunderstorms look
likely from 11 to 17z from KOFK to KOMA. Wind gusts over 40 kts
are possible with the onset of the storms, and rain will likely
last for 2 to 3 hours after onset at a particular location. After
storms move out of the area, mid/high clouds are expected to
stick around along with the northwesterly winds to close out the
TAF period.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Heat Advisory until 8 PM CDT this evening for NEZ011-012-015>018-
033-034-044-045-051>053-066>068.
IA...None.
&&
$$
DISCUSSION...Nicolaisen
AVIATION...Petersen