Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 05/13/23
Area Forecast Discussion
National Weather Service Fort Worth TX
646 PM CDT Fri May 12 2023
...New Aviation, Short Term...
.SHORT TERM... /NEW/
Update:
Upstream convection to our west/northwest has been on the slower
side of guidance in terms of development and upscale growth so far
today. Most of this morning`s HREF suite has been way off the
mark in terms of activity in southwestern Oklahoma, and was much
too aggressive in depicting an MCS developing and sweeping through
North Texas this afternoon/evening. Recent runs of the HRRR/WoFS
have caught up to present radar trends, and are depicting a slower
and more realistic scenario for the arrival of an MCS from the
west later this evening/tonight.
It does still appear that one or more MCS segments will organize
from West Texas activity during the next few hours which will
spread into most of the forecast area tonight. While this
convection could pose a hail/wind threat on an isolated basis,
the greater concern will be heavy rain and flooding, particularly
west of I-35 where training convection is possible. The Flood
Watch configuration remains adequate at this time, and no further
eastward expansion is presently planned. There is still
considerable uncertainty of coverage of thunderstorms tomorrow
which will depend heavily on how convective trends evolve in the
next 12 hours.
-Stalley
Previous Discussion:
/This Afternoon through Saturday Night/
A warm and unstable airmass is in place across Central and North
Texas this afternoon and some warm advection showers have started
to develop beneath what was a fairly strong cap this morning.
Latest RAP objective analysis and an aircraft sounding from
earlier suggest this capping has weakened and we should see a
slight uptick in scattered afternoon thunderstorms mainly south of
I-20. This activity will be aided by weak ascent ahead of a slow
moving upper trough over north-central Mexico. Farther to the
northwest, a frontal boundary and surface dryline are positioned
from north to south across western Oklahoma and into northwest
Texas. A warm and humid airmass to the east of this boundary
yields around 4000+ J/kg of most unstable CAPE and will fuel
thunderstorm development through the late afternoon and early
evening. It`s a little uncertain whether or not this activity will
directly impact North Texas as the boundary is still displaced to
the northwest, but several of the high resolution CAMs rapidly
develop convection, then spread it east into North Texas along
surging outflows early this evening. We`ll keep PoP around 30-40%
across the northwest this evening with a substantial uptick in
rain chances expected overnight. Any storms that develop this
afternoon/evening have the potential to become severe with a
damaging wind and hail threat. This severe threat will taper off
tonight with heavy rainfall becoming more of a threat overnight.
The aforementioned upper trough will spread out of northern Mexico
and into the Southern Plains overnight tonight with persistent
lift occurring throughout much of Central Texas. This should keep
scattered to numerous showers and thunderstorms ongoing overnight,
particularly west of I-35. As the trough continues northward on
Saturday, a steady stream of moisture will persist through Central
and North Texas with PWs increasing to 1.8". Deep meridional flow
will favor training showers and thunderstorms which will likely
produce bands of heavier rainfall. This is most likely to occur
along and west of I-35, tied to the strongest forcing for ascent.
Rain chances will continue into Saturday night across the entire
region.
A Flood Watch is in effect for areas west of I-35 currently,
however, an expansion may be needed at some point over the weekend.
Widespread rainfall amounts of 1-3 inches can be expected west of
I-35 with lesser amounts to the east. The potential for training
showers and storms means that some locations will likely see
considerably more rainfall.
Dunn
&&
.LONG TERM... /Issued 323 PM CDT Fri May 12 2023/
/Sunday Onward/
With no significant pattern change in the forecast through the
next week or so, expect an unsettled weather pattern to persist
across North and Central Texas. Periods of heavy rain will
increase the flash flooding potential, thus, a Flood Watch is in
effect through Sunday evening.
As we begin the new week, our region will be on the eastern
periphery of a mid-level trough that will gradually be retreating
eastward. Given the trough`s influence, southerly flow will
continue to advect plenty of moisture northward into a weakly
forced environment. Even with weak forcing, sufficient daytime
heating will promote the development of isolated to scattered
showers and thunderstorms on Sunday along any remnant boundary.
The retreating trough will allow for an area of high pressure to
shift eastward across the Lower Mississippi River. The weakened
southerly flow may lead to a weak front moving in on Monday
afternoon. Although there may be increased surface convergence
along the front, weak deep layer shear and low instability should
keep the threat for severe weather at bay. Weak impulses are
likely to traverse across the region, and although overall storm
chance will remain low, there will continue to be isolated to
scattered showers and storms each day.
The aforementioned area of high pressure will be temporary as the
expectation is that by mid-week, the longwave trough across the
eastern CONUS will strengthen and return an active weather pattern
to our region to finish out the work week. As we approach next
weekend, guidance continues to advertise a cold front moving into
our region with high pressure settling in behind the front. If
this is the case, there may be a break in precipitation next
weekend.
Hernandez
&&
.AVIATION... /NEW/
/00z TAFs/
Timing of convective impacts to D10 airports has been pushed back
slightly with the 00z TAF updates with radar trends and model
guidance suggesting a North Texas arrival around/after 04z. While
impacts to the western cornerposts are possible earlier than
that, the most likely timing for storms in the immediate vicinity
of the TAF sites is from 05-11z. Afterwards, lighter showers and
probably less frequent lightning activity could linger into early
Sunday morning before a break in activity through midday. Ragged
MVFR stratus may attempt to develop during this time period as
well, but any nearby convection could certainly interrupt or delay
its formation. Isolated/scattered thunderstorm redevelopment is
expected with daytime heating, and intermittent convective impacts
seem likely through the afternoon and early evening period
tomorrow. Outside of influences from thunderstorm outflow, a SE
wind will prevail.
-Stalley
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 69 82 68 83 67 / 70 60 60 60 40
Waco 68 79 66 80 66 / 70 70 60 70 40
Paris 67 84 66 85 67 / 30 50 40 40 30
Denton 67 81 65 81 64 / 70 60 60 60 50
McKinney 67 82 66 82 66 / 60 70 50 50 40
Dallas 70 83 68 84 68 / 70 70 50 60 40
Terrell 69 83 67 84 67 / 30 60 50 50 40
Corsicana 71 84 68 85 67 / 40 60 50 50 30
Temple 68 79 66 80 65 / 60 70 60 70 40
Mineral Wells 66 78 64 78 64 / 70 70 70 70 60
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Sunday evening for TXZ091-100>102-115>117-
129>132-141>144-156>160-174.
&&
$$
Area Forecast Discussion
National Weather Service Indianapolis IN
938 PM EDT Fri May 12 2023
.Forecast Update...
Issued at 938 PM EDT Fri May 12 2023
Earlier convection from the afternoon had moved well to the north
and east of the forecast area this evening with only a few light
showers present. With the warm front north of the area and moist
southerly flow...01Z temps remained in the upper 60s and lower 70s
over much of the forecast area with a muggy feel to the airmass.
With the exception of the earlier activity during the second half of
the afternoon...the convective expectations across central Indiana
to this point have underwhelmed and not sure that changes much for
the rest of the night. The airmass remains weakly unstable with the
bulk of the SBCAPE west of the region...and forcing aloft is not
overly impressive. The mid and upper level flow will continue in a
quasi-zonal pattern through the night with a few subtle waves
drifting through the area. But that combined with minimal
instability will limit convection to largely isolated in coverage
with many locations remaining dry overnight. Have cut back on pops
accordingly.
The bigger impact for the overnight is the expected expansion of
lower stratus already present over south central Indiana and a
growing confidence in at least patchy fog development after 06Z
persisting through daybreak. Model soundings and low level RH progs
both support stratus and fog becoming more prevalent as the night
progresses.
Lows will remain warm in the mid and upper 60s. Zone and grid
updates out.
&&
.Short Term...(This evening through Saturday)
Issued at 300 PM EDT Fri May 12 2023
- Chance of showers/T-storms Tonight and Saturday
- Very warm Saturday. Afternoon highs in the upper 70s to middle 80s
.Tonight...
This afternoon featured a moist column per BUFKIT and ACARs
soundings, 305K Isentropic lift, a pair of upper waves around the
northwestern Kansas upper low, southerly low level flow and a weakly
to moderately unstable atmosphere (surface CAPEs 500 to 1500 J/kg).
These ingredients and eroding cap have failed to lead to increasing
convection to this point, and lightning has been absent. Still
expect upper wave, currently over eastern Missouri, to eventually
get things rocking and rolling by late this afternoon.
As the Plains low lifts north tonight an associated front will setup
somewhere across central Indiana. Meanwhile, drier air will move in
aloft and keep enough instability around for the convection to
continue through the night. The lingering cloud cover and
convection, mid 60s dew points and light south winds will keep
temperatures from falling lower than the mid 60s overnight.
.Saturday...
Dry air will remain in place aloft on Saturday per BUFKIT soundings
and RH progs as upper flow becomes northwest, due to a building
southern ridge and weakening northern Plains upper low. This will
result in enough sunshine to allow temperatures to climb to well
above normal during the afternoon. That combined with some lingering
low level moisture and will also result in a more unstable
atmosphere than today with SB CAPEs to near 2000 J/kg possible. The
biggest question for tomorrow will be where will the surface
boundary be located? Primary indications are it will be somewhere
from the I-70 corridor to western Kentucky. CAMs suggest
thunderstorms will erupt near and north of this boundary during the
afternoon over parts of central Indiana. The further south the front
ends up, the lower the potential for convection will be over central
Indiana. With this uncertainty ongoing, will stick with chance PoPs
with the best chances over south central sections. Dry air aloft
supports SPC Day2 Marginal Risk for severe thunderstorms. With low
level inflow weak and deep shear marginal, large hail and perhaps a
downburst will be the main severe risks.
Temperatures will also be conditionally based on where the front
settles but confident with plenty of sunshine, upper 70s to mid 80s
are likely with the warmest temperatures over southwestern sections.
&&
.Long Term...(Saturday night through Friday)
Issued at 302 PM EDT Fri May 12 2023
* Scattered showers/t-storms through weekend, *conditional* severe
threat greatest Sunday afternoon and evening
* Mainly dry and pleasant workweek with seasonably mild temperatures
Saturday Night and Sunday...
The rather humid pattern will continue through the remainder of the
weekend...although latest guidance is continuing to suggest more
reasonable dewpoints amid a mainly easterly flow...following the
quasi-stationary surface boundary`s passage back southward towards
the Ohio Valley late Saturday. Nevertheless the cold-side broad
surface ridge will stay retracted well to our north, allowing the
system`s frontal zone and theta-E gradient to stretch from northern
Illinois to southern Ohio...and therefore across our local region.
Saturday Night...suspect any organized scattered showers/non-severe
storms from Saturday to diminish in coverage Saturday night along
with once-adequate CAPE waning early in the evening. Any isolated
stronger TRWs at this time would need to be fueled by elevated
support, or perhaps arrive later at night from the west-northwest as
part of a MCS. Both scenarios are possible yet not likely, with
lackluster mid-level lapse rates and any MCS/remnants to be focused
near/south of Terre Haute and toward pre-dawn hours.
Sunday...Attention then turns to Sunday with the greatest chance of
severe weather in the next week. The overall pattern with the theta-
E gradient and aloft frontal zone both stretched across the CWA will
continue. High/very high levels of vertical wind shear will cross
the region from the WNW to ESE through the Sunday afternoon and
evening hours...although this well-timed potential will likely match
with zero/near-zero instability given our proximity on the cooler
side of the surface front, what should be BKN/OVC decks limiting
surface hearing, and even mediocre 700-500mb lapse rates.
Nevertheless, any partial clearing could result in strong convective
initiation. Any daytime thunderstorms could persist several hours
into the overnight amid the highly sheared column...even cells
initiating well to our west that may arrive after dark.
Very high precipitable water values for mid-May...generally 1.0-1.5
inches along the usual north-south gradient...would fuel any
potentially heavier downpours, yet suspect storm motion would be
great enough and antecedent moisture low enough to prevent any
flooding concerns. Total additional rainfall for the Saturday night-
Sunday period should be under 1.00 inch, with most locations
expected to pick-up less than 0.50 inch. Temperatures will exhibit
a limited range amid considerable cloudiness and still somewhat
humid conditions...with lows Saturday night expected to range from
the upper 50s to mid-60s...and highs Sunday in the 70s.
Monday through Friday...
The overall synoptic pattern will continue for the workweek...with
an elongated upper ridge aligned from the northern Rockies to the
Deep South...while the last gasps of late winter attempt to hold on
under pronounced troughs passing through eastern Canada. Indiana
will find itself between these features, with confidence increasing
that the local region catches the southern edge of the cooler, drier
Canadian flow. The first cold frontal zone should be pushing
southward through the CWA early Monday, bringing a much drier column
and surface dewpoints to 40F or lower. No evidence to suggest ample
moisture becoming trapped amid the modest subsidence, so suspect
ample May sunshine...amid light breezes backing from northeast to
westerly as the surface ridge axis crosses the region from north to
south through the early week.
Ensembles favoring no major changes to the overall light and west-
northwesterly steering flow aloft through next week, which should
allow a second potent Canadian trough to drag another cold front
south through the Midwest during the midweek. The associated,
subsequent surface ridge may have a bit more gumption than the early
week, while passing from the Great Lakes to the Mid-Atlantic. A
more southerly flow into Indiana would be favored given the ridge
tracking to our east, which may return enough moisture to allow for
widely-scattered showers. Several seasonably mild days are expected
through the workweek, with temperatures generally ranging from cool
mornings in the low to mid-50s to very mild days in the mid to upper
70s.
&&
.Aviation...(00Z TAF Issuance)
Issued at 655 PM EDT Fri May 12 2023
Impacts:
* Restrictions developing overnight and peaking early
Saturday morning with IFR and lower conditions possible
* Scattered showers and a few storms possible through the forecast
period with greatest chances this evening and Saturday morning
Chaotic pattern into Saturday as a warm front settles across
northern Indiana tonight...then slips back to the southwest by
Saturday night. This is creating a lower than desired confidence in
aviation concerns across central Indiana into Saturday.
Quasi-zonal flow aloft present with multiple subtle waves drifting
across the Ohio Valley. Combined with a weakly unstable airmass over
the region...a periodic threat will exist for isolated to scattered
convection into Saturday. The best potential to see any convective
impacts at the terminals will be into the early overnight and again
Saturday morning with precip coverage diminishing for Saturday
afternoon. These impacts are likely to be brief at any one point.
The much greater impact to aviation operations across the region
will be the expansion of lower stratus late evening into the
overnight with model soundings and RH progs both suggesting
increased confidence in sub-IFR conditions developing during the
predawn hours and likely lasting into Saturday morning. VFR
conditions will return by midday Saturday.
Wind directions will be variable throughout the forecast
period...but a general S/SW flow this evening will eventually
transition to E/NE by Saturday afternoon as the aforementioned
boundary drops back southwest across the area.
&&
.IND WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Update...Ryan
Short Term...MK
Long Term...AGM
Aviation...Ryan