Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/09/19
Area Forecast Discussion
National Weather Service Denver/Boulder CO
804 PM MDT Mon Jul 8 2019
.UPDATE...
Issued at 710 PM MDT Mon Jul 8 2019
The strongest thunderstorms from earlier this afternoon have
weaken while pushing eastward out of the area this evening.
Therefore, have allowed the Severe Thunderstorm Watch to expire
early for all of the far eastern counties. Expanded coverage of
pops for a few extra hours across the foothills and Urban Corridor
locations due to the last batch of scattered showers moving off
the higher terrain. Water vapor channel starting to show much
drier air aloft edging into the state from southwest and will
expect showers to diminish through 04z. Otherwise, current
forecast is on track.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 303 PM MDT Mon Jul 8 2019
Scattered thunderstorms have been developing on the plains over
the last couple hours with a combination of showers and outflow
boundaries currently being depicted in the radar data. Some storms
on the plains will be strong enough to produce hail and/or
damaging winds for the next couple hours. Shower activity extends
back into the mountains as far west as KRIL and as far south as
KALS. This line defines the back edge of the short wave trough
that we have been tracking. As the trough continues in
northeastward track, shower activity is expected to continue
developing ahead of it. The HRRR shows that the majority of shower
activity will be finished by 8 PM MDT with only isolated, weaker
showers after that. Thunderstorms on the eastern plains will tap
into better moisture and be strong to severe for the next couple
hours. Forecast will show thunderstorms through the early evening
and then rapid clearing by midnight.
For Tuesday, drier westerly flow will prevail, leading to a rare
summer day with no afternoon convection over the forecast area.
Skies will be mostly sunny with temperatures warmer than today.
.LONG TERM...(Tuesday night through Monday)
Issued at 303 PM MDT Mon Jul 8 2019
For Tuesday night into Wednesday, a closed low will be to the North
over North Dakota with the trough extending into portions of eastern
Wyoming and Nebraska. A boundary bringing slightly cooler air and
increasing stability will push into the northern plains by the
evening hours on Tuesday helping to cap convection for Wednesday
and decrease highs slightly into the lower to mid 80s. The only
exceptions would be the higher elevations where there would be
enough moisture to help diurnal heating spark some isolated
convection by the late afternoon hours. Some models are more
excited about these storms than others so will keep pops in the
slight chance area for now.
By late Wednesday into Thursday, the 596 DM ridge will continue to
build over the desert SW cutting off moisture for much of the state.
Models show some moisture making it under the ridge in the mid-
levels on Thursday. The focus for isolated storms will mainly be
over the higher terrain with just a slight chance across the Palmer
Divide given increased NE flow from a circulation over the southern
foothills. Storms will mainly produce light rain with some gusty
winds. Temperatures will rebound slightly with highs across the
plains in the lower 90s with 70s in the mountains.
For the latter half of the week, the ridge remains in place over the
region with an increasing plume of moisture from the desert SW.
Precipitable water (PW) values will increase starting Saturday with
GFS putting over an inch across the eastern plains through Sunday.
Storm coverage is expected to increase through the weekend. Friday
will be more isolated over the higher terrain and Park county with
Saturday having more widespread scattered storms into the evening
hours. Models show CAPE values increasing Saturday with values
from 500 to just over 1500 j/kg over the far NE plains. Steering
flow will be decent between 12 and 18 kts with deep layer shear
just between 20 and 25 kts. PW values will be around 0.90 inches
by Saturday evening. These storms could produce moderate to heavy
rain and gusty winds. Similar story for Sunday with slightly lower
confidence on storms making it onto the plains. Models are
showing increased warming in the mid-levels over portions of the
plains with increasing upper level zonal flow. Storms could have a
hard time surviving as the move east off the higher terrain. If
they are able to survive, the main hazards will be gusty winds
with DCAPE values near 1500 j/kg. Highs over the weekend will
reach back into the lower 90s with 70s expected in the high
country.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 710 PM MDT Mon Jul 8 2019
The greater coverage of showers and thunderstorm from earlier this
afternoon have pushed well east of the terminals. Clearing skies
should be the rule through the evening and overnight hours. Drier
westerly flow aloft will then bring mostly clear skies and
unlimited visibilities through Tuesday afternoon. Winds will
return to drainage southerlies this evening and then be light and
westerly through tomorrow.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Fredin
SHORT TERM...Dankers
LONG TERM...Bowen
AVIATION...Fredin
Area Forecast Discussion
National Weather Service Billings MT
834 PM MDT Mon Jul 8 2019
.UPDATE...
Severe convection and heavy rain continue to shift east this
evening. Have extended the Severe Thunderstorm Watch til 11 pm for
Custer, Fallon, Powder River and Carter Counties. Activity has
weakened to the west and have cancelled Rosebud, Treasure, Big
Horn and Sheridan Counties. JKL
&&
.SHORT TERM...valid for Tdy and Tue...
Potential exists for severe thunderstorms and flash flooding this
evening. BE PREPARED!
Convection already developing over the Beartooth Absarokas at 1140
am. Latest mesoanalysis shows capping across our lower elevations,
but since this morning`s activity we`ve had a few hours of sun
which is helping to destabilize our air mass. We are already
seeing temps in the 70s, with dew points mainly in the 50s, except
low 60s in our far east. Recent HRRR runs show convection
initiating in our southwest at 19-20z, but this is too late given
what we are seeing now. Water vapor imagery shows a seasonally
strong shortwave lifting thru the great basin, and this will
provide plenty of large scale ascent for today`s convection.
Ingredients are all coming together for a risk of both severe
storms (mainly hail/wind) and flash flooding (pwats over an inch)
this afternoon and evening. CAMs show a couple rounds of storms
moving thru, and this seems reasonable given the ascent. Moisture
will be greatest east of Yellowstone County, an area that has seen
significant rainfall over the past several days. Storms will be
moving, but any heavy rain (or multiple rounds of heavy rain) on
top of saturated soil could produce flash flooding. The potential
for severe weather will last til around midnight in our far east.
For Billings, 3-9 pm seems to be the prime time.
Cooler air will surge in tonight behind a cold front, and the
upper trof axis will finally shift east early tomorrow. We will
see hints of a trowal as the low deepens to our northeast, and
looks like a good chance of showers even in the morning on
Tuesday. Low will pull away later in the day but with enough
diurnal instability under the NW flow aloft to keep scattered
showers going thru the afternoon and early evening. Freezing
levels will be quite a bit lower under the upper trof, the GFS
shows wet bulb zero heights around 7kft agl, so expect small hail
with any modest thunderstorm that develops.
Tuesday high temps will be only in the low-mid 70s. After a
relatively chilly night, upper level ridge will build in for drier
and warmer conditions on Wednesday. We should see highs get
closer to normal and in the 80s.
JKL
.LONG TERM...valid for Wed...Thu...Fri...Sat...Sun...
Upper ridge over the area on Thursday gets flattened with a
shortwave moving through the region. Some late day showers and
thunderstorms are possible over western areas. Ridging builds back
over the region Friday and through much of the weekend, with moisture
and energy advecting into the area, undercutting the ridge.
Showers and thunderstorms look possible most afternoons/evenings
in this monsoonal pattern. High temperatures look to range from
the middle to upper 80s most days, with low temperatures mainly in
the 50s. STP
&&
.AVIATION...
Potential exists for severe thunderstorms east of KBIL through the
evening, with large hail, strong winds and very heavy rain
possible. Storms will produce a brief period of MVFR or lower
flight conditions. To the west, showers with a few embedded
thunderstorms will produce local MVFR, and mountains will be
occasionally obscured.
More showers w/ scattered thunderstorms can be expected on
Tuesday, along with breezy NW winds. Small hail is possible with
any storm, along with localized MVFR conditions. Mountains will be
frequently obscured. NW winds will gust from 20-30 kts across the
east, including KMLS and KBHK.
JKL
&&
.PRELIMINARY POINT TEMP/POPS...
Tdy Tue Wed Thu Fri Sat Sun
-------------------------------------------------------
BIL 080 056/073 054/085 062/087 061/085 062/089 063/091
+/T 96/T 20/B 02/T 21/U 11/B 21/U
LVM 075 049/074 047/084 055/086 055/085 055/087 057/088
9/T 85/T 00/B 12/T 22/T 22/T 23/T
HDN 080 056/072 052/085 059/086 060/084 061/089 062/091
8/T 96/T 20/B 01/U 11/B 11/B 20/U
MLS 084 058/070 051/081 059/087 060/084 061/088 063/090
4/T +8/T 30/U 00/U 11/U 21/U 21/U
4BQ 082 057/071 050/081 059/087 060/084 061/087 062/090
4/T +8/T 30/U 01/U 12/T 22/T 21/U
BHK 083 057/068 049/078 057/085 059/082 060/086 061/088
4/T +9/T 50/U 01/U 11/U 21/U 21/U
SHR 081 052/072 047/085 057/088 057/084 057/087 059/091
7/T 96/T 20/U 02/T 24/T 33/T 31/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Flash Flood Watch in effect until 6 AM MDT Tuesday FOR ZONES
30>33-36>38-57-58.
Severe Thunderstorm Watch 499 in effect until 11 PM MDT this
evening FOR ZONES 32-33-36-37.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service Cheyenne WY
651 PM MDT Mon Jul 8 2019
.UPDATE...
Issued at 649 PM MDT Mon Jul 8 2019
The Severe Thunderstorm Watch for the southern Nebraska Panhandle
has been canceled. The line of thunderstorms has moved out of our
area, and the severe threat has diminished for the day.
UPDATE Issued at 334 PM MDT Mon Jul 8 2019
A Severe Thunderstorm Watch is now in effect for counties in the
southern Nebraska Panhandle including Scotts Bluff, Banner,
Morrill, Kimball, and Cheyenne Counties until 10 PM tonight. A
line of thunderstorms is moving out of eastern Wyoming and into
western Nebraska. The main threats with this line of storms are wind
gusts up to 70 MPH and hail up to 2 inches in diameter. Heavy
rainfall is also possible.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 220 PM MDT Mon Jul 8 2019
Forecast concerns in the short term deal with severe thunderstorm
chances/locations both today and Tuesday.
Currently...Cold front lays across east central Wyoming this
afternoon from a surface low over northwestern South Dakota. Mid
60 dewpoints in the Panhandle with 64 being reported at
Alliance...63 at Sidney and 65 at Chadron. Water vapor imagery
showing an upper level disturbance moving into the central
Colorado/Wyoming state line at this time. 250mb jet around
50-55kts moving into the area with this shortwave. Thunderstorms
are beginning to develop along the Laramie Range...moving very
slowly to the east. Seeing outflow boundaries emanating from these
storms along the I-80 corridor. With the slow storm motions...do
expect erratic storm motions.
Latest SPC Mesoanalysis showing best instability over the
Panhandle this afternoon. By mid afternoon...looking at surface
based CAPE values on the order of 4000 J/KG out near Bridgeport.
Not a whole lot of shear out there with light low level winds.
Effective Bulk Shear around 20kts down near the southern
Panhandle. So not really looking at extremely large hail. Better
severe hazards may be heavy rain today. Latest HRRR shows on its
simulated radar forecast for storms to slowly shift east into the
Panhandle through 01Z. Given storms we have received the past
several days...did not want to go with no severe storms this
afternoon. Do expect severe storms to be on the low end though
this afternoon.
For Tuesday...Showing a surface boundary pushing southeast out of
north central Wyoming Tuesday afternoon with upper level trough
moving through late afternoon. Will need to watch the timing on
this front/shortwave as SPC does have a Slight Risk area for the
northern Panhandle.
.LONG TERM...(Tuesday night through Monday)
Issued at 220 PM MDT Mon Jul 8 2019
Drier and warmer period for Wednesday through Friday as upper
level ridge builds into the area from the south. Could see some
fire weather issues as afternoon humidity falls below 15 percent
each day...expanding east each day. Fortunately...fuels are still
reported as green...so chances for fire starts are small.
One final thing for the weekend...backdoor cold front set to move
back into the area Friday afternoon/evening from the north. So
looks like storms returning for the weekend.
For way out there...GFS and ECMWF beginning to show the onset of
the monsoon with a Four Corners high setting up and qpf
developing over northern Mexico. This qpf makes it up into
northern Colorado by mid week next week. Just on time for
Frontier Days.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 513 PM MDT Mon Jul 8 2019
Latest radar loop was showing a line of thunderstorms stretching
from Alliance to Sidney. This line should exit the area by 01z or
so. Gusty west winds have been following this line due to good
subsidence in the stratiform region. Meanwhile, more isolated
convection was moving through Carbon county. This convection may
produce some gusty winds, but this convection should die off after
sunset. Meanwhile, wind speeds are expected to be quite gusty
&&
.FIRE WEATHER...
Issued at 220 PM MDT Mon Jul 8 2019
Scattered to numerous showers and thunderstorms this
afternoon...mainly along and south of the Interstate 80 Corridor.
One more day of wetting rains mainly east of the Laramie Range for
Tuesday. High pressure then builds into the area for Wednesday
with very dry air. Afternoon humidity becoming critical each day
through Friday...especially along and west of the Laramie Range.
Overnight humidity recoveries poor Thursday and Friday mornings. Gusty
west winds to 30 mph possible...could lead to areas of critical
fire weather. Fortunately...fuels are still being reported as not
ready...so fire weather concerns should be minimal. Unsettled
weather returns to southeast Wyoming and Nebraska Panhandle by the
weekend with increasing chances for wetting rains.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
UPDATE...CW
SHORT TERM...GCC
LONG TERM...GCC
AVIATION...REC
FIRE WEATHER...GCC
Area Forecast Discussion
National Weather Service Wichita KS
650 PM CDT Mon Jul 8 2019
.SHORT TERM...(This evening through Thursday night)
Issued at 314 PM CDT Mon Jul 8 2019
Tonight:
Anticipate ongoing high precipitation storms will dwindle this
evening with loss of heating. Still appears probable that storms
rolling off High Plains will move into central KS sometime around
or just after midnight, given favorable upper support. Anticipate
storms will hold together overnight given the upper diffluent and
departing jet streak. The unknown is the southern extent of the
storms towards daybreak, which would be further removed from
upper support, but into a more moisture rich environment. Quick
peek at 1800 UTC SPC HRRR looks to be in the ballpark both the
rest of this afternoon and tonight.
Tuesday:
Think some showers/storms will probably be ongoing in the morning
across Flint Hills and into southeast KS. It is possible
precipitation might end in the morning, but thinking middle level
warm air advection and MCV would keep it festering. It is not
inconceivable that precipitation could linger/expand back across
central KS in the morning with middle level warm air advection.
With additional heating in the afternoon and plenty of moisture,
think storms will either develop or increase in the afternoon,
aided by outflow from morning storms.
Tues night-Thursday:
Front will likely push through sometime Tuesday night or
Wednesday, with a fair amount of slop on timing between various
models. Odds likely favor slower arrival if storms are less
organized Tuesday night. Kept small chances going in southeast KS
Tuesday night ahead of front. Drier air supposedly filters in
during the day Wednesday. Still not entirely convinced that
Wednesday will be completely dry - thinking slower frontal passage
is more likely, but consensus dictated a dry forecast on
Wednesday. Expansive surface high pressure will cover the area
later Wednesday through Thursday.
.LONG TERM...(Friday through Monday)
Issued at 314 PM CDT Mon Jul 8 2019
Weak return flow develops on Friday, with a slow increase in low
level moisture. Rising upper heights also signals an increase in
temperatures. There is an outside chance of isolated storms Sunday
afternoon in southeast KS and then again Monday, but chances were
too low to include at this point. Of note, ECMWF still shows
remnants of tropical system approaching area late Monday. -Howerton
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 644 PM CDT Mon Jul 8 2019
Main forecast concern will be storm chances tonight.
Storms that developed late this afternoon have pushed north and
convection over southeast KS is slowly pushing southeast. Next
chance for storms will come as the activity over the High Plains
works east tonight. Current thinking is that areas generally north
of Highway 50 will have the best chance to be affected generally
around or shortly after 06z, with strong winds being the main
threat. This activity should also push outflow south, which should
temporary flip winds around to the northeast.
&&
.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT 72 93 74 92 / 20 10 10 10
Hutchinson 71 93 72 91 / 30 10 10 10
Newton 71 92 72 90 / 30 20 10 10
ElDorado 72 91 73 90 / 20 20 20 10
Winfield-KWLD 72 91 73 92 / 20 10 20 10
Russell 66 94 68 89 / 70 10 10 0
Great Bend 67 93 69 90 / 50 10 10 0
Salina 70 93 71 90 / 60 20 10 10
McPherson 70 92 71 90 / 40 20 10 10
Coffeyville 73 91 74 94 / 40 20 30 10
Chanute 72 90 74 92 / 30 30 20 10
Iola 72 90 74 92 / 30 30 20 10
Parsons-KPPF 73 90 74 93 / 30 20 20 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...PJH
LONG TERM...PJH
AVIATION...RBL
Area Forecast Discussion
National Weather Service Key West FL
1039 PM EDT Mon Jul 8 2019
.DISCUSSION...
Temperatures this evening are already near forecast overnight
lows, but they shouldn`t fall much more as light south to
southwest winds have developed and will persist overnight. Boca
Chica is the warm spot of the Keys recording 85 degrees at 10 PM,
with Big Pine Key the cool spot clocking in at 79 degrees. Mid
70`s dew points are found all across the Keys and coastal waters.
Radar returns have dropped off substantially this evening, with a
very distinct dry area aloft (800-550 mb) on the evening sounding.
This area is capped off by an impressive inversion around 500 mb,
where there is very little adiabatic cooling for a depth of about
4000 ft. These features are in good agreement with the lack of
convection that we are seeing. Upper-level cloud cover is still
plentiful, with northerlies near the jet stream level continuing
to transport thunderstorm exhaust from our north over the region.
Concerning the forecast, the primary change from the afternoon
package was to lower PoPs for much of the overnight period. Short
term high resolution CAMs are in great agreement with MOS guidance
in continuing this lull in precipitation until the early morning
hours. As the atmosphere recovers from earlier convection, we are
still in a prime area of upper-level support as lobes of vorticity
pivot around the area of troughiness wedged between ridges to our
east and west. Southwesterly transport of moisture in the low-
levels will be the main catalyst to prime the atmosphere for new
convective initiation. The HRRR paints a picture of localized
convergence across the island chain sparking the development of
scattered showers and eventually thunderstorms after dawn. The
rest of the forecast is on track.
&&
.MARINE...
Light to gentle south to southwest breezes can be expected across
the coastal waters of the Florida Keys tonight. Although formation
of a tropical system is becoming increasingly likely in the
northeastern Gulf of Mexico later this week, the Keys will remain
on the periphery with no significant impacts other than increased
chances for showers and thunderstorms.
&&
.AVIATION...
A cyclonic low-level envelope is in place across Florida, with the
apex extending south of the Upper Keys. Long duration satellite and
radar loops reveal storm motion in line with the cyclonic envelope.
This evening`s KKEY 00Z RAOB sampled a distinct drop in TPW compared
to 12 hours ago. Of particular note, extremely dry air near 700 mb,
corroborated by composite 700-500 LPW satellite products. Moisture
recovering south to southwesterly BL winds should develop overnight
and showers are included in the vicinity of both terminals after
10Z. Statistical guidance once again agrees with our assessment of
thunder chances after 15Z. Prepare for spells of MVFR CIGS/IFR VIS
and convective wind gusts near 20 knots. Similar to today, a
distinct stable/dry period is expected after the storms.
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...None.
&&
$$
Public/Marine/Fire...WLC
Aviation/Nowcasts....CLR
Data Collection......DR
Visit us on the web at weather.gov/key
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Area Forecast Discussion
National Weather Service North Platte NE
642 PM CDT Mon Jul 8 2019
.SHORT TERM...(This evening through Tuesday night)
Issued at 118 PM CDT Mon Jul 8 2019
MCV is tracking northeast across southwest and south central
Nebraska this afternoon. Lift enhanced by the MCV is helping to
regenerate thunderstorm development across southwest Nebraska. In
addition to the MCV, large scale ascent is overspreading the area as
an upper trough approaches from the west. Storms should continue to
develop near the MCV late this afternoon and evening, with additional
thunderstorms forming across the western High Plains as the upper
trough approaches. PWATS are quite high, ranging from 1.3 to 1.5
inches across the region. Heavy rainfall can be expected with the
thunderstorm activity this evening. There is a lesser threat for
severe storms with weak shear and mid-level lapse rates around 6.5
C/km likely limiting the potential. The main severe threat would be
from strong outflow winds. The area most prone to see heavy rainfall
will be across portions of southwest Nebraska, where storms will be
most persistent due to the remnant MCV.
The upper trough tracks eastward across the Central and Northern
Plains Tuesday. This will result in a surface low developing across
North Dakota. A cold front will develop southwest from the low and
track into northwest Nebraska during the late afternoon hours.
Isolated thunderstorm development is possible along the front. CAPE
looks less than previous days but overall shear is stronger. Appears
that even though coverage will be isolated, shear supports the
potential for a supercell, and 12Z HRRR supports this scenario and
tracks a strong cell across Sheridan into Cherry county. Otherwise
expect a warm up ahead of the front...with highs nearing 90 across
portions of southwest Nebraska. Mid to upper 80s can be expected
elsewhere.
.LONG TERM...(Wednesday through Monday)
Issued at 118 PM CDT Mon Jul 8 2019
Warmer and drier weather is expected by the middle and end of the
work week. The GEFS and ECMWF build upper level ridging into the
four corners region and much of the Central and Southern Plains.
This will spread a warm layer aloft across the region which will
limit rain chances. The upper ridge will flatten just a bit Friday
night into the weekend, which will allow for a couple of weak
disturbances to migrate eastward across the area on the northern
periphery of the ridge. Isolated to scattered thunderstorm chances
will return as a result.
Above normal temperatures are expected with highs climbing into the
lower 90s Thursday into the weekend. Climate Prediction Center is
forecasting above normal temperatures and below normal precipitation
for both the 6 to 10 and 8 to 14 day outlook - a first for this
Summer.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 637 PM CDT Mon Jul 8 2019
Scattered thunderstorms this evening into the overnight across
western, southwest and north central Nebraska. Thunderstorms
should move out of the forecast area after 2am continuing into
central and eastern Nebraska. Skies should clear tomorrow morning
with VFR conditions.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...Taylor
LONG TERM...Taylor
AVIATION...Gomez
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
540 PM CDT Mon Jul 8 2019
.SHORT TERM...
241 PM CDT
Through Tuesday...
There are no significant concerns in the forecast through Tuesday
afternoon. Main item of note continues to be lingering haze from
wildfire smoke. HRRR experimental smoke fields show decreasing
concentration this evening into the overnight, so will carry
definite haze mention through mid evening. Area web cams indicate
that most visibility is 6+ miles in the haze, though possibly
locally around 4-5 miles. Suspect that the 2-3 mile visibility
being reported as of 2pm hour at DuPage Airport (DPA), Aurora
Airport (ARR) and Schaumburg Airport (06C) is overdone considering
FAA observers carrying 10 mile visibility at ORD and MDW. Winds
will be light easterly to calm/variable tonight, and with dew
points mixing out this afternoon along with clear skies tonight,
expecting lows in the upper 50s to lower 60s outside of Chicago
tonight (locally mid 50s near WI state line). Mid 60s will be the
rule in/near downtown Chicago.
On Tuesday, we`ll start to lose influence of departing surface
high pressure, as winds turn southeast/south-southeast
synoptically. Gradient will certainly remain weak enough for a
lake breeze to form and push inland, much farther so into Illinois
than northwest Indiana due to southeast synoptic component.
Warming thermal profiles will support highs in the 84-88 range,
including northwest Indiana near the lake prior to lake breeze
passage. The Illinois shore will top out in the mid to upper 70s.
There will be increasing high cloud cover through the afternoon.
Regarding humidity on Tuesday, lingering dry air aloft and mixing
into this should support dew points topping out in upper 50s-low
60s northeast IL and NW IN. With higher Td not far away to our
south, increasing southerly flow should increase dew points into
mid to upper 60s well inland in Illinois, making it a bit more
uncomfortable there during the afternoon.
Castro
&&
.LONG TERM...
312 PM CDT
Tuesday night and Wednesday...
A shortwave trough is projected to eject northeastward out ahead of
a larger mid-level trough that will move into the upper Great Plains
on Tuesday. This shortwave trough should have enough forcing
associated with it to generate convection over portions of Iowa and
Missouri on Tuesday night that should slowly decay overnight into
Wednesday morning as it works its way eastward into a stabilized
environment across northern Illinois.
Depending on how much this initial period of clouds/showers
influences the atmospheric conditions near the surface, a threat of
severe weather may exist later in the day. In the wake of this
shortwave trough, a cold front associated a surface low working its
way across Lake Superior will pass through the CWA sometime late
Wednesday afternoon/early Wednesday evening. Surface heating
throughout the day is expected to destabilize the boundary layer in
the thermal ridge out ahead of the cold front with temperatures
expected to rise into the low 90s and heat indices possibly
breaching the 100 degree threshold. This heating will lead to large
CAPE values, possibly in excess of 3000 J/kg in some areas. This
large amount of instability, coupled with pre-frontal moisture
advection and effective bulk shear values approaching 40 kts will
create an environment that will be conditionally favorable for
severe storms with large hail and damaging winds to fire up along
the aforementioned cold front in the late afternoon/early evening.
However, some uncertainty remains with the location and timing of
the development of the initial convection, as models disagree over
the timing of the frontal passage and the amount of influence the
earlier convection will have. While most models are supportive of
storm formation over southern Wisconsin and northern Illinois in the
late afternoon/early evening, some guidance suggests that the cold
front may pass through earlier in the afternoon, preventing the
atmosphere from destabilizing enough in time for storms to develop
over northern Illinois, instead favoring storm initiation over
northern Indiana. In addition, the main core of forcing for ascent
looks to remain displaced immediately to our north. However, hodographs
suggest that any initial storms that develop may initially be
discrete and supercellular before clustering and becoming more
linear over time. The main window for a severe potential seems to
be during the late afternoon into the early-evening hours on
Wednesday.
Ogorek
Wednesday night through Monday...
A noticeably drier and somewhat cooler airmass will descend upon
the region Wednesday evening and into Thursday in the wake of
evening storms and the attendant cold front. Thursday is shaping
up to be a pretty fantastic day featuring high temperatures either
side of 80 degrees with dewpoints which will probably mix out into
the upper 50s and lower 60s. Combined with a slight northwest
breeze (which will likely turn out of the north or northeast in
the afternoon near the lakeshore), can`t do much better in the
middle of July.
As the spine of a surface ridge builds across the region on
Friday, moisture will begin to creep upwards once again, however,
with dewpoints in the upper 60s and lower 70s looking like they`ll
return through the afternoon hours. The heat and humidity will
only build from there into the weekend, with afternoon heat
indices looking like they`ll once again make a run into the mid
and upper 90s across much of the region.
The core of the subtropical high will begin to build northward
Friday and through the weekend, settling across the Four Corners
region and into the Central Great Plains. As this occurs, we`ll be
located at the southern terminus of stronger northwesterly flow
aloft. Global model guidance hints at an initial mid-level
perturbation possibly drifting towards the region either late
Friday night or into Saturday afternoon. The presence of
strengthening 500 mb flow (40-45 kts), steepening mid-level lapse
rates at the edge of an expanding EML plume, and increasing
moisture in the 700-500 mb layer supports some potential for
elevated convection. This might occur across portions of northern
Iowa or southern Minnesota late Friday night and into Saturday
morning at the nose of a strengthening low-level jet. Should
storms develop, there`s a non-zero potential this activity could
congeal into a complex and press into our northern zones into
Saturday afternoon. Obviously a low confidence forecast, but opted
to throw in some low storm chances mainly near and north of I-80
to account for this potential.
We`ll remain in a pattern supportive for showers and storms into
Sunday, although confidence in this remains too low to warrant any
explicit precipitation mention at this juncture.
Carlaw
&&
.AVIATION...
For the 00Z TAFs...
Only forecast points of interest during this 00Z TAF cycle are:
- Possible smoke impacts on visibility tonight and early Tuesday
morning
- Likely lake breeze passage at ORD and MDW Tuesday afternoon
High pressure is centered over Michigan early this evening and
trapped within this light low to mid-level flow is smoke
originating from central Canadian fires. This smoke has provided
a milky white appearance to the sky as far south as the I-80
corridor in Illinois, and has resulted in a few northern Illinois
sites reporting 2-5 SM visibility. ORD and MDW have not been two
of those sites but it is possible tonight if some of this smoke
settles below the developing inversion. Also outlying airports
such as DPA and RFD that are reporting 3-5 SM already as of 23Z
could drop solidly into IFR visibility tonight if indeed the
smoke does settle lower.
For Tuesday, southeast winds will gradually increase, at times
possibly near due south, topping out near 10 kt. A lake breeze
will develop and there is medium-high confidence in this easterly
wind shift reaching ORD and MDW. Timing of this shift in the
current TAF has medium confidence.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
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Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1019 PM CDT Mon Jul 8 2019
.SHORT TERM... (Through Late Tuesday Afternoon)
Issued at 942 PM CDT Mon Jul 8 2019
Quiet weather is occurring across the CWA with isolated thunderstorms
staying near the stationary front over far southern Missouri into
eastern Kansas. Will maintain a dry forecast until late tonight
when latest RAP runs continue to show weak low level moisture
convergence over central Missouri which supports going isolated
thunderstorms. Going low forecasts look good.
Britt
.LONG TERM... (Wednesday through Next Monday)
Issued at 330 PM CDT Mon Jul 8 2019
The greatest weather impacts and threat potential resides on
Wednesday and there continues to be a fair amount of uncertainty
in some of the specifics, especially with regards to heat. The
concern is that clouds and/or ongoing showers and thunderstorms on
Wednesday morning could hamper heating. Basically kept close to
the previous forecast for both heat and thunderstorm chances. The
upper level trof currently in the Pacific Northwest will migrate
eastward through the upper-mid MS Valley and into the Great Lakes
on Wednesday into Wednesday evening sending a cold front and
accompanying pre-frontal trof through the area on Wednesday
afternoon and evening. Summer heat and humidity will be back
provide the morning cloud/precipitation scenario is at a minimum.
Afternoon temperatures in the upper 80s and lower 90s will
contribute to SBCAPE of 4000-5000 j/kg and little CIN. The
advancing boundaries should be able to initiate scattered
thunderstorms, with deep layer shear in the 20-30 kt range
favoring multicell modes. The combo of shear and instability would
suggest a few severe storms would be possible per the latest SPC
day3 outlooks with damaging winds and large hail the primary
threat. We are still anticipating heat index values of 100-105
across portions of east central MO and southwest IL centered on
metro St. Louis, and ultimately a heat advisory may be necessary.
It still looks like we finally see a respite from the heat and
especially humidity in the wake of the front on Thursday-Friday
with northwest flow aloft and controlling surface high pressure.
However model consensus shows that by the weekend an upper
high/ridge will build and elongate from the southern Rockies
eastward into the MS Valley bringing a return of the heat and
eventually humidity.
Glass
&&
.AVIATION... (For the 06z TAFs through 06z Tuesday Night)
Issued at 1013 PM CDT Mon Jul 8 2019
Dry and VFR conditions are expected to continue through late
tonight before a isolated thunderstorms move into central Missouri
which will affect KCOU. The chance of thunderstorms will spread
east and increase during the morning affecting KUIN and the St.
Louis area terminals by 18Z. The chance of thunderstorms will
continue at all of the terminals through 00Z with MVFR/possible
IFR ceilings and visibilities. Scattered thunderstorms will then
be confined to parts of central and northeast Missouri as well as
west central Illinois including COU and UIN after 00Z.
SPECIFICS FOR KSTL:
Mainly dry and VFR conditions are expected through 18Z Tuesday. The
chance of thunderstorms will continue until 00Z with
MVFR/possible IFR ceilings and visibilities. Winds will remain
light through the period.
Britt
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Marquette MI
753 PM EDT Mon Jul 8 2019
.SHORT TERM...(This evening through Tuesday)
Issued at 235 PM EDT MON JUL 8 2019
Per RAP analysis, broad surface high pressure centered over the
Upper Great Lakes has been nearly stationary. Satellite imagery
continues to show a broad area of elevated smoke, thicker over the
south-central than elsewhere. Diurnal cumulus has developed this
afternoon in Gogebic and Ontonagon Counties where the smoke has
generally cleared. The HRRR-smoke runs today have consistently
indicated more low level smoke over the east half, and this is
supported by reduced visibility to 5-8SM at KSAW and KERY at times
this afternoon. However, reduced visibility has also been reported
at KCMX, in Baraga County and at KIMT as well, so perhaps the model
is underdoing low level smoke over the central and west. Regardless,
afternoon temperatures have risen into the 75-83 degree range
inland, lowest south-central where the smoke layer is thickest.
Lakeside locations remain in the upper 60s.
As high pressure slowly moves off to the east, surface low pressure
crossing North Dakota will bring a slight increase to gradient
southerlies and southwesterlies at low to mid levels over Upper
Michigan. This should aid in dispersing the smoke, and as such it is
expected to gradually thin out from west to east overnight into
Tuesday. Lows will fall into the 50s for most, with some lower 60s
far west and a cold spot or two inland falling to around 49.
Some smaller concentrations of smoke are likely to still be floating
around tomorrow but will not be as ubiquitous or have as much of an
affect on temperatures. Early indications are that it will remain
thicker over the east and perhaps wrap around to the far west as
well, but given the HRRR-smoke didn`t have the best handle on it
today, have opted to hold off on adding smoke to the forecast after
12Z tomorrow. With more modest southerly flow, highs should easily
reach the 80s except for in locations near Lake Michigan and a few
spots right along the shores of Lake Superior like Grand Marais and
Copper Harbor. Clouds should begin to move in from the west during
the evening hours, but we are expected to remain dry though this
forecast period.
.LONG TERM...(Tuesday night through Monday)
Issued at 326 PM EDT MON JUL 8 2019
The long-term starts with an amplifying upper-level short wave over
the Northern Plains and WAA out ahead of it over the Upper Great
Lakes. Models depict enough moisture convergence and isentropic lift
with the warm front for showers Tuesday night, mainly across the
west and perhaps making it to the central U.P. by Wednesday morning.
The NAM shows just enough elevated CAPE that there could be a rumble
of thunder with these showers, but most of the destabilization is
behind the front so have kept capped thunder chances at slight for
now.
The main story this week will be the potential for strong to severe
thunderstorms on Wednesday as the aforementioned short wave moves
closer. As far as potential severe wx setups go in this part of the
country, the model solutions over the past two days have been
remarkably consistent. The GFS, NAM, EC, etc. all march the short
wave currently over the Pac NW eastward across the northern tier of
the U.S. tonight and tomorrow, to be overhead late Wednesday. Out
ahead of the associated cold front, warm moist southerly flow allows
modeled surface based CAPE values to rise to as high as 4000 J/kg.
Even with surface dew points probably overdone by a few degrees, and
assuming a bit more mixing, still looking at MLCAPE AOA 2000 J/kg
and MLLCLs < 1000 m. Seasonally strong mid-level flow through this
short wave means effective shear of anywhere from 35 to as high as
50 knots, which given the aforementioned buoyancy, would support
supercells along the cold front.
Any limiting factors? Yes, plenty. Given lack of a well-defined EML
in most (but not all) model solutions over the past couple of days,
and thus mid-level lapse rates that are a not-so-impressive 5.5 to
6.5 K/km, think severe hail will be less of a concern than severe
wind gusts - though that is not to say the most robust storms
couldn`t still support a few isolated instances of severe hail.
Timing is also a factor. The front looks to race across Upper
Michigan from west to east in as little as 9 hours, so a
difference of just a couple hours in FROPA timing could force it
through too quickly before diurnal instability builds, or too late
after it has already waned. Also, southerly surface flow off Lake
Michigan will stabilize the low levels over the east, forcing
storms to go elevated there and thus reducing the severe weather
risk. Could also end up with too much cloud debris from morning
showers and not realize all of the instability that`s modeled. To
summarize... Wednesday looks like the best severe weather setup
we`ve seen in our area so far this year (though that`s not saying
much), but it`s not without its caveats. For now, the best advice
is simply to continue watching. One last note, given fat CAPE
profiles and seasonally fast storm motions, do not expect flash
flooding to be a concern except perhaps in very isolated pockets.
Now for the rest of the long-term... Thursday looks cool and
comfortable behind the cold front with 850 mb temps dropping to
about 10 C and thus highs should stay in the upper 70s inland and in
the 60s along Lake Superior given NW surface flow. With cooler air
aloft, should mix down enough wind for 20-30 mph gusts Thursday both
on land and on the water.
WAA returns Friday and 850 temps quickly climb back to 15-17 C, so
will likely see highs back in the mid to upper 80s away from
Superior Friday. Models also bring another short wave/cold front
through and show enough shear/instability for another round of
thunderstorms, though obviously this is less certain simply given
how far out in time it is. Given right now this looks like an
overall weaker system, the amount of cooling behind the front looks
less than what`s expected Thursday. Therefore, looks like we stay in
the 80s for the weekend (inland). Though still far out, fairly good
model consensus right now that next week will be hot. With 850 temps
climbing to 20-22 C (gross!) could see highs near 90 with enough
sunshine, or at least 80s and high humidity. Hey, at least it`s not
fire weather.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 753 PM EDT MON JUL 8 2019
Although high pres will be drifting e away from the area tonight and
Tue, a dry air mass will linger, allowing for VFR conditions at
KIWD/KCMX/KSAW thru this fcst period. Only exception will be smoke
from Canadian wildfires that mixed down sufficiently to lead to some
vis restriction today. An MVFR vis may continue at KSAW this
evening. Otherwise, the elevated smoke layer will gradually thin out
over the next 24hrs.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 235 PM EDT MON JUL 8 2019
Winds under 20 knots are expected to prevail through Tuesday as high
pressure moves overhead. There is a chance for a brief period of 20-
25 knot winds Tuesday night over the central lake. A cold front will
pass through on Wednesday night and winds may increase to 25 knots
behind it over all zones except 162 and 263. Expect these elevated
winds to persist into Thursday. Through the end of the week into
early parts of next weekend, winds will again remain below 20
knots. Some fog is also a good bet Wednesday given the warmer
moister air moving in and showers moving across the lake, but
exactly where and how dense is still uncertain. Whatever does form
Wednesday should dissipate by midday Thursday given the amount of
wind behind the cold front.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...KCW
LONG TERM...RJC
AVIATION...Rolfson
MARINE...KCW/RJC
Area Forecast Discussion
National Weather Service Pueblo CO
336 PM MDT Mon Jul 8 2019
.SHORT TERM...(This evening through Tuesday)
Issued at 336 PM MDT Mon Jul 8 2019
Currently...Shortwave in the southwest flow aloft was tracking
across the state, tapping into the available moisture for isolated
convection across the forecast area. Temps have warmed into the 70s
for the high valleys as of 3 pm, and into the 80s to lower 90s for
the plains.
Tonight and Tomorrow...Latest HRRR model runs have a fairly decent
handle on current convection, and indicate that activity will
persist along the I-25 corridor until around 6 pm, then quickly exit
across the eastern plains between 8 and 9 pm. This is due to the
upper shortwave exiting the region, then as the upper trough crosses
the northern Rockies flow aloft becomes westerly. This westerly flow
will dry out the forecast area overnight through tomorrow, making
for mostly clear skies overnight and plenty of sun tomorrow.
The Marginal area for severe weather is still in place across the
far eastern plains, and with higher available precipitable water
amounts across the east, storms developing over or moving into
Kiowa, Bent and Prowers Counties will still need to be watched
closely through the early evening.
Clearing skies tonight will allow temps to drop into the upper 30s
to mid 40s for the high valleys, and 50s to near 60F for the plains.
Max temps tomorrow will heat up into the 80s for the high valleys,
and upper 80s to mid 90s for the plains. Moore
.LONG TERM...(Tuesday night through Monday)
Issued at 336 PM MDT Mon Jul 8 2019
Initially, basically dry meteorological conditions are expected
from Tuesday evening into early Wednesday afternoon as supported
by projected Interstate 25 precipitable water values dropping
form over 1 inch today(Monday) to under 0.70 inches in
combination with healthy upper ridging building over southern
Colorado during this time-frame. In addition, cooler maximum
temperatures are expected Wednesday afternoon in the wake of a dry
northerly surface surge moving across eastern locations Tuesday
night.
Upper ridging is then expected to remain anchored over southern
Colorado and northern New Mexico from later Wednesday into next
Monday, allowing near to above seasonal early to mid July temperatures
to prevail over the CWA during the period.
In addition, increased projected precipitable water values from
Wednesday afternoon into Friday and especially from this weekend
into possibly next Monday in combination with the diurnal heating
cycle and passing generally weak upper disturbances will allow
for increasing precipitation chances, favoring this weekend into
possibly next Monday(where an elevated potential for locally heavy
rainfall and associated primarily recent burn scar flash flood
risks may occur if recent trends continue).
Finally, latest longer range forecast model soundings and
computer simulations continue to signal that generally low-grade
gradient winds should be noted over the majority of the CWA during
the balance of the longer term.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 336 PM MDT Mon Jul 8 2019
VFR conditions expected across much of the forecast area over the
next 24 hrs, including the three main TAF sites of KCOS, KPUB and
KALS. Showers and storms have developed across the forecast area
this afternoon and may affect TAF sites through 00z this eve, with
all activity forecast to exit the plains between 02z-03z. Conditions
may become MVFR to at times IFR under heavier showers and storms.
Clearing skies then tonight, with mostly clear conditions overnight
and tomorrow morning.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$