Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 07/01/19
Area Forecast Discussion
National Weather Service Fort Worth TX
656 PM CDT Sun Jun 30 2019
.AVIATION...
/00Z TAFs/
Concerns for this TAF period are the potential for ceiling
reductions around daybreak Monday and convective impacts from
morning into the afternoon.
In the meantime, have removed mention of VCSH from Metroplex TAFs.
Visible satellite trends and AMDAR data from Love Field indicate
cumulus should remain shallow enough to prevent development around
local sites. At KACT, adjusted VCTS to VCSH, and this may be
generous given similar trends. Nocturnal cooling should reduce
convective chances further later this evening.
A notable change in this forecast cycle is the introduction of
VCSH around daybreak Monday. Short-term guidance suggests a weak
impulse will pivot around the periphery of the broader inverted
trough, yielding enough deep-layer ascent for at least isolated
showers. Cannot rule out a thunderstorm, as well, but not
confident enough in this outcome to mention in TAFs during the
morning. By mid-day, adequate (albeit perhaps muted) heating
should offer enough buoyancy for deeper convection. Thus, TAFs
then advertise VCTS into the mid afternoon hours. Thereafter,
deep-layer ascent is expected to have shifted north of the
Metroplex, bringing an end to convective potential. Still, some
deviations will be possible north of DFW into early evening.
As for CIGs, southerly 925mb flow will increase overnight,
bringing transient saturation around 015-030 across KACT and
towards the Metroplex around 11-13Z. Confidence in MVFR CIGs at
Metroplex sites is not particularly high, though; therefore, TAFs
advertise only a TEMPO group of high-end MVFR.
Picca
&&
.SHORT TERM... /Issued 314 PM CDT Sun Jun 30 2019/
/Through Monday Morning/
Overall the short term forecast period should feature slightly
quieter weather, as showers and a few isolated storms will be the
primary concern. Otherwise, overnight lows will be seasonal
averages.
A diffuse MCV continues to churn across the Brazos Valley this
afternoon and will be the culprit for afternoon showers and a few
isolated thunderstorms. Indeed...weak convection has proliferated
along the northern flank of this MCV near and north of the I-20
corridor along an axis of low level moisture convergence. This
activity will continue to slide towards the west through the
afternoon. While instability continues to build beneath the warm
and moist atmosphere...modest subsidence will likely suppress
updrafts such that efficient growth stunts the lightning
potential. Still...a handful of storms remain possible and will be
hazardous to those with outdoor festivities. The other area that
we will continue to monitor for additional CI will be down across
Central TX...though visible imagery from GOES suggests a rather
flat CU field. Still...will continue a mention of chance showers
and storms across this area. Overall kinematic and thermodynamic
profiles do not appear to support a gusty to damaging wind convective
event that we saw on Saturday afternoon/evening. That in mind,
the strongest storms will still be capable of strong to near-
severe caliber winds.
Showers and thunderstorms will be largely diurnally driven with
the exception of any clusters that establish a decent cold pool
and persist a little after dark. The most likely area for this
will be across East and Central Texas. There`s a low risk for
patchy fog on Monday morning across areas that experience
rain/storms and can clear out. This also appears most likely
across East and Central Texas.
Bain
&&
.LONG TERM... /Issued 314 PM CDT Sun Jun 30 2019/
/This Week and Next Weekend/
A lingering mid-level weakness aloft will remain across North and
Central Texas through the July 4th holiday and result in low
convective chances across varying parts of the area. Trying to
pinpoint the subtle, meandering shortwave energy aloft,
differential heating from anvil debris of convection, and location
of mainly diurnal convection always poses significant challenges
for even CAMs as today has shown quite well given the post-storm
subsidence. Either way, a strong storm or two with gusty winds,
frequent lightning, and small hail can`t be ruled out through this
period. Any severe weather threat appears pretty low and not any
one location will be a washout for outdoor events, especially
those celebrating the holiday with fireworks. That said, it won`t
be completely hot n` rain/storm-free like usual and if you plan
on attending such events, you need to have some source of weather
information and be ready to find shelter if a storm were to pop
up on or near you while outdoors. Typical summertime humidity
will be around each day with highs averaging in the mid-upper 80s
southeast to the lower 90s far northwest. Though humid, enough
mixing will occur by each afternoon to keep heat index values well
below advisory criteria and below 100 "feel-like" degrees.
A broad, but not overly intense subtropical upper ridge will
expand across the southern tier of the country from Texas to
Florida, but the higher mid level heights will remain offshore
across the Gulf of Mexico Friday into next weekend. Mainly
isolated convective chances will occur this period north of the
I-20 corridor....where subsidence will not be overly strong. From
Central Texas southward, a stronger subsident airmass will be
present. High temperatures more conducive for moving into early
July will return with highs in the lower-middle 90s and a few
locations in eastern Central Texas seeing heat index values around
the century mark. Though delayed, Summer is slowly making its
appearance across the region and what we`re used to this time of
year.
South-southeast breezes 10-15 mph with occasional gusts over 20
mph during the day are generally anticipated each day, as the main
jet stream and storm track remain well north of the area.
05/
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 73 89 74 91 74 / 20 40 20 10 0
Waco 72 88 72 89 72 / 30 30 10 20 10
Paris 71 85 71 87 70 / 30 50 30 20 0
Denton 72 89 73 91 72 / 20 30 20 10 0
McKinney 70 87 72 89 72 / 30 40 20 10 0
Dallas 74 89 75 91 74 / 20 40 20 10 0
Terrell 70 87 72 91 72 / 30 40 20 10 5
Corsicana 71 86 70 86 70 / 30 40 10 20 10
Temple 71 88 71 89 71 / 40 30 10 20 10
Mineral Wells 71 88 71 91 70 / 10 20 10 10 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
11
Area Forecast Discussion
National Weather Service Louisville KY
1003 PM EDT Sun Jun 30 2019
.Forecast Update...
Issued at 1003 PM EDT Sun Jun 30 2019
Have dropped the watch as the storms have weakened and the gust
front has moved well south.
Storms over central Illinois continue to show a general weakening
trend, with the strongest storms showing a more southward push
toward western and southern Illinois.
Issued at 858 PM EDT Sun Jun 30 2019
Have dropped a few counties in southern Indiana from the Severe
Thunderstorm Watch behind the line of storms crossing the Ohio River
into Kentucky.
Still watching the MCS moving into central Illinois from eastern
Iowa. Latest radar returns have shown a slight decrease in intensity
and the outflow rushing out ahead. IR satellite shows cloud tops
warming. 850-300 flow would steer the complex SSEwd, eventually into
areas affected by the first MCS. So, still leaning toward the idea
of it weakening as it approaches, but watching it closely.
Issued at 755 PM EDT Sun Jun 30 2019
SPC has issued a Severe Thunderstorm Watch west of Louisville for a
few hours this evening as a severe MCS drops south out of Indiana.
This threat should be relatively short-lived as CIN increases and
there isn`t much upper support to keep it going at severe levels.
Also, cloud tops have shown a slight warming trend and a gust front
from earlier convection will be undercutting the incoming
thunderstorms.
The next MCS up over eastern Iowa and northern Illinois will also
head southeast but current indications are that it won`t make it as
far as the Ohio Valley, or at least as little more than a shadow of
its former self.
&&
.Short Term...(This evening through Monday)
Issued at 215 PM EDT Sun Jun 30 2019
Have a couple of things to watch for in the near term. First will be
the strength of scattered to numerous storms forming over the next
several hours. Temperatures have gotten into the low 90s at each of
our climate sites. With dewpoints around 70 and model and AMDAR
soundings showing little if any inhibition, expect cells to start
popping along axis where cumulus field has formed...running from
Scottsburg, IN to Crestwood and Nicholasville in KY. Outflow
boundaries will take over after that, with a general westward drift
in coverage this evening.
The second issue will be storms, now over the WI/IL border, dropping
in late this evening/overnight. Most hi-res guidance has these cells
dying off before they get here, as our environment likely will get
worked over by this afternoon/evening`s convection. Still cannot
rule out some elevated cells or even just cloud cover lingering into
the overnight period.
Lastly, moisture from rain falling in the evening and light winds
overnight should lead to some fog formation. Have highlighted area
river valleys for areas of fog, but have patchy fog wording
elsewhere. Guidance is not coming in overly dense with this
fog...and it`s not the time of year for dense fog to form
either...but will watch for development overnight.
.Long Term...(Monday night through Sunday)
Updated at 225 PM EDT Sun Jun 30 2019
Unsettled conditions are expected to continue throughout the work
week, as a upper level trough to our north moves through the Great
Lakes region. Isolated to scattered showers/storms will be possible
across much of our area Tuesday through Thursday, especially with
the aid of diurnal heating and any outflow boundaries that head
south into our region. Fortunately, these showers/storms will be
short lived, so not expecting much in the way of rainfall totals.
Highs during the work week are forecast to remain in the upper 80s
to lower 90s. However, dewpoints in the mid to low 70s will cause
heat index values to climb into the upper 90s. Summer is definitely
coming in HOT!
As we head into the weekend, precip chances really begin to ramp up
as a cold front extending southwest from Ontario into Iowa begins
diving southeast into our region. As a result, showers will be
likely ahead of this boundary. While model soundings show plenty of
instability, shear values are lacking, which will cause any
organized convection to be limited. Highs are forecast to cool of
slightly this weekend with values reaching the mid to upper 80s.
&&
.Aviation...(00Z TAF Issuance)
Updated at 728 PM EDT Sun Jun 30 2019
Line of strong storms this evening has cleared SDF and LEX, but will
move through HNB in the first couple hours of the TAF period. There
is some question of whether or not they will make it all the way
down to BWG...at this time will keep them out of the BWG TAF but
will keep an eye on it. Even if BWG doesn`t get storms they may
still be affected by the southward-pushing outflow from the storms
to their north.
Additional storms over Wisconsin and Iowa are moving into northern
Illinois but are not expected to make it to the TAF sites. Still,
something to keep an eye on tonight.
Went ahead and included some BR at LEX towards dawn since they
received a little bit of rain earlier. Kept it out of drier BWG.
Tomorrow looks a little quieter with weak surface ridging and ridge
building aloft. Widely scattered convection still possible, but will
keep TAFs dry for now.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Update...13
Short Term...RJS
Long Term...SSC
Aviation...13
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
651 PM CDT Sun Jun 30 2019
.MESOSCALE DISCUSSION...
555 PM CDT
Flipping the calendar back exactly five years ago today provides
a guide for how the rest of the evening could evolve, although
mainly west of the I-39 corridor rather than across the Kankakee
Valley as it did five years ago. Though hopefully things will not
get quite as active as that event.
The concern is the approaching cluster of severe storms moving in
from southwest WI. SPC mesoanalysis suggests an axis of large
instability remains in place across western IL while areas in the
wake of today`s first event are more worked over. We do not
however know with confidence how shallow the stable layer might
be. We do know there has already been one tornado warning issued
upstream. 0-1km SRH values on the mesoanalysis page in the 100-200
m2/s2 range across that area are not terribly high, but like five
years ago these are probably underdone by quite a bit based on
the unrepresentative and too slow storm motion around 15 kts used
to calculate these values. Instead the leading edge of the line
has been moving closer to 50 kts which would greatly ramp up the
SRH values and support a greater tornadic threat than might
otherwise be expected.
This of course depends on the stable surface layer being shallow
enough to allow for development of surface based parcels, and that
remains the key question at this time. A couple of AMDAR
soundings out of MDW and ORD suggest the stable layer is around
2000` deep at this time, which may be enough to suppress activity
at the surface, but this is farther downstream of the approaching
cluster and more recently affected by the first round of activity.
The other hint of a lingering surface stable layer is the
widespread AP seen on radar to our west, though this also was
present during the 2014 event up to the time that tornadoes
started to develop.
What isn`t as evident this evening so far is the location of a
remnant outflow boundary from the first event, which would serve
to focus the development of tornadic activity. So for now the
tornado threat does not appear to be high relative to a renewed
damaging wind threat, but if outflow from the initial storms today
manages to evolve into an effective warm front across NW IL then
things could get more active.
Another key factor that is missing relative to five years ago is
sufficient deep layer shear to assist in organization and
maintenance of the activity this evening. Winds at 500mb are only
in the 25-30kt range.
The most likely outcome is that the strongest part of the system
stays west of our area and begins to dissipate as it moves into
the relatively more stable downstream airmass over us. But we are
just trying to convey the full range of possibilities.
Lenning
&&
.SHORT TERM...
419 PM CDT
Through Monday...
Complex of storms which moved through the area today continues to
slowly drift to the south southeast. A severe threat remains for
locations along/south of the Kankakee river valley through the 5
to 6 pm cdt time frame. Overall precip chances will lower during
this time, but continue to monitor additional upstream development
across southwest WI which is also moving to the south. These
additional showers/storms will likely reach the IL/WI border by 7
and then possibly continue south through 8-9. With more stable
conditions in place across northern IL, the storm intensity should
remain limited. However, will continue to monitor this as it is
still somewhat early, with some clearing occurring across southern
WI and northern IL that could aid in more favorable conditions
for thunderstorm intensification.
Confidence does lower with additional thunderstorm chances later
tonight into early Monday morning. However, with some focus
remaining in place tonight along with moisture/instability
centering overhead, can`t rule out at least some isolated to
scattered thunderstorms tonight. Do have chance pops to account
for this, but will need to monitor this time frame for isolated
stronger storms as well as the possibility for additional heavy
rainfall and localized flooding.
Rodriguez
&&
.LONG TERM...
419 PM CDT
Monday night through Saturday...
Through much of the upcoming week we should continue to see
seasonably warm and humid conditions with at least periodic
chances of showers and thunderstorms as the region remains on the
periphery of the upper ridge which should move to the southeastern
U.S. Strong shortwave trough over southeastern Canada could
provide enough oomph to push a cold front south across the area
late in the week. The front could provide a focus for greater
coverage of convection as it moves through, followed by
potentially some less humid conditions with lesser rain chances by
Friday into the start of next weekend. Generally speaking it
should be a typical summertime set up with ample instability but
lacking in shear, so at this point, barring any convective
enhancements to shear profiles, looks like many more days this
upcoming week with a marginal/low end severe weather threat due to
the instability.
Rodriguez/Izzi
&&
.AVIATION...
For the 00Z TAFs...
Ongoing severe convection in western IL near the MS River will
continue tracking south over the next couple hours. The eastern
extent of this activity will likely soon affect RFD, and clip the
Chicago metro sites mid-evening.
After a lull in activity late this evening into the early
overnight, increase warm air advection may initiate renewed
convection across portions of northern IL. Confidence has
increased enough to introduce a VCTS from 08-11Z, with activity
possibly remaining just west of the Chicago metro. There is also
the chance that activity will linger later than 11Z, but
confidence is fairly low at this time. Increasing capping will
likely end any convection by mid-morning Monday at the latest,
keeping the remainder of the period dry.
Regarding winds, light NW winds at TAF issuance may briefly become
NE/E/SE with a modest outflow boundary shifting south near the
WI/IL state line. A brief 10-20min period of gusts to 15 kts will
be possible along the immediate boundary before winds likely
settle to light SE. SW winds are then expected overnight through
Monday, with a Lake MI lake breeze likely remaining pinned to the
lakeshore and away from ORD/MDW.
Kluber
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
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