Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 05/09/23
forecast discussion, the NBM probabilities continue to indicate
greater than 50% chance of at least 3 inches of rain from Friday
through the weekend. While this is a good sign that a lot of the
area will receive beneficial rainfall, there is the concern for
Flash Flooding, if too much rain comes down in a too short of a
period of time. Otherwise, expect for cooler daytime temperatures
with all the cloud cover and moisture while the overnights will
remain warm and humid. Stay tuned to the forecast during the days
ahead as confidence increases leading up to this potential heavy
rainfall event.
&&
.AVIATION...
(00Z TAFS)
Issued at 623 PM CDT Mon May 8 2023
A cluster of SHRA/TSRA will impact KAUS in the next few hours and
have gone with TEMPOs through 03Z. As SHRA/TSRA get further organized
over west central Texas and near the Rio Grande this evening they may
impact KSAT/KSSF overnight and have replaced TEMPOs with VCTS. Then,
SHRA/TSRA will redevelop on Tuesday and have maintained PROB30s for
the afternoon hours. Otherwise, VFR skies turn MVFR overnight, then
gradually lift on Tuesday. Light to moderate S to SE winds prevail.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 70 85 68 81 / 10 50 30 50
Austin Bergstrom Intl Airport 68 84 66 80 / 10 50 30 50
New Braunfels Muni Airport 70 85 68 81 / 20 50 30 50
Burnet Muni Airport 67 84 66 81 / 30 40 20 40
Del Rio Intl Airport 71 93 72 90 / 30 30 40 20
Georgetown Muni Airport 68 84 66 79 / 10 50 30 50
Hondo Muni Airport 69 87 69 84 / 30 40 30 40
San Marcos Muni Airport 69 84 67 80 / 20 50 30 50
La Grange - Fayette Regional 72 82 69 81 / 20 60 40 50
San Antonio Intl Airport 70 85 69 81 / 20 50 30 40
Stinson Muni Airport 71 86 70 83 / 20 50 30 40
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term...04
Long-Term...05
Aviation...04
Area Forecast Discussion
National Weather Service Indianapolis IN
1013 PM EDT Mon May 8 2023
.Forecast Update...
Issued at 1013 PM EDT Mon May 8 2023
Latest observations across the region continue to show slow
stabilization of the surface layer. As temperatures cool, expect any
lingering instability to wane. Recent ACARS soundings out of IND
conquer, with a subtle near-surface inversion beginning to form.
There are a few lingering showers out there, but these have been
weakening since sunset and that trend is expected to continue. As
such, thunderstorms are no longer expected and the severe weather
threat has ended. Additionally, a weak cold front is now sagging
southward across the CWA.
Cirrus from thunderstorms in Missouri should cross the region at
some point tonight. Bumped up sky cover grids after midnight to
account for this. Some stratocumulus associated with the weak cold
front will also increase in coverage. These clouds could moderate
temperatures slightly should a more expansive coverage be realized.
Nevertheless, with weak cold air advection in place lows should be
cooler tonight compared to recent nights with values into the
mid to lower 50s.
&&
.Short Term...(This evening through Tuesday)
Issued at 255 PM EDT Mon May 8 2023
This afternoon through evening...
Main concerns:
* Timing/Coverage for thunderstorms
* Instability supporting stronger cores and severe weather
Discussion: Cirrus shield continues to slide east over Indiana, but
some erosion to the shield has occurred and is allowing some marginal
destabilization to the lower levels of the atmos. A cirrus shield is
developing along an axis/boundary that exists from earlier
convection, presently oriented from Central Illinois stretching
southeast through Southern Indiana. This is where we are beginning
to see some marginal building or vertical growth to the cumulus
field, which suggests presence of lift of parcels. Coupled with the
guidance soundings in this area indicating a moist column, along
with steepening mid-lvl lapse rates. Trend has been for the steeper
lapse rates over Missouri/Southwest Illinois to eventually reach
Southwest Indiana by 21Z. But what is keeping things in check thus
far has been a bit of a cap or inversion aloft. This does appear to
be dissipating as time progresses.
Elsewhere another channel of clouds that is along an old boundary
and much higher dewpoints was oriented across Central/Southern
Missouri and stretched east through Southern Illinois. This appears
to be shaping up to the main focal for upscale growth to any
convection that can initiate. This area is also along the transition
or gradient of much more unstable air, so additional processes are
likely going to take place and equally favor more development over
the next few hours.
The current expectations are that we will start to see some spotty
showers developing west of Lafayette in Illinois, reaching Northwest
Indiana around 20-21Z, then possibly some continued development
further east through sunset. But the greater focus is further south,
and initiation for convection along/south of I-70 will be dependent
upon the moist/boundary in Southern Illinois. Dewpoints continue to
pool into the mid/upper 60s in that area, so expect if storms do
develop they`d arrive in southern Indiana or along a Terre Haute to
Bloomington to Seymour line and south closer to 23Z.
While the main focus has been on convective development, the
integrated moisture is present and the forward speed does appear to
be present. That being said, there could be some heavy downpours
from efficient processes.
Overnight: Expect any ongoing convection to steadily slide southeast
with the axis of deeper moisture and 1-3km flow oriented southeast,
500mb weak troughing will pivot overhead as well, which will equally
help to nudge any ongoing convection further southeast. Clouds will
remain through the overnight, with flow slowly turning northwesterly
behind the boundary. By daybreak heights will be steadily rising,
with diffluent flow aloft helping to slowly erode any stratus deck
that has lingered overnight. Northerly flow will assist with some
drying as well, with the bulk of the overnight expected to remain
dry.
Tuesday: 500mb ridging continues to build overhead, with diffluent
low-levels continue to dry out the surface. Currently anticipate Tue
to be a beautiful day with highs in the low 70s and abundant
sunshine by midday.
&&
.Long Term...(Tuesday night through Monday)
Issued at 255 PM EDT Mon May 8 2023
* Above normal temperatures much of the long term.
* Dry and pleasant mid week, with shower and storm chances returning
late week into the weekend.
The main driver of the weather over the next 3-7 days will be an
amplifying trough over the eastern Pacific over the next couple
days. Currently, an elongated upper level ridge is situated over a
majority of the CONUS. However, as this low deepens west of CA,
broad WAA will induce height rises over the Plains, leading to
primarily ridging by mid-week over the Great Lakes and Ohio Valley.
This should keep the near to above normal temperatures Tuesday night
through Thursday night, with the warmest temperatures expected on
Thursday as the ridge axis centers over the region. Broad subsidence
upstream of the ridge with no low level disturbances will also lead
to a brief dry stretch.
By Friday, uncertainty will increase with central Indiana situated
in the periphery of the upper level ridge to the east and the
aforementioned trough to the west. This should induce moisture return
within unified SW flow, increasing instability and chances for
showers/thunderstorms. Uncertainty remains high, but expect multiple
rounds of showers and thunderstorms Friday through Sunday as mid to
upper level troughing remains just upstream. Severe thunderstorms
cannot be ruled out with the potential of locally enhanced shear;
however, a large scale disturbance does not look likely at this
time.
Temperatures late this week into the weekend should remain warm, but
additional cloud cover, and rain/moisture should limit diurnal
warming some. Current expectation is for most areas to be in the
upper 70s with isolated locations in the low 80s, depended on
mesoscale influences.
&&
.Aviation...(18Z TAF Issuance)
Issued at 528 PM EDT Mon May 8 2023
Impacts:
- Scattered to numerous thunderstorms along with MVFR conditions
will be possible at any of the terminals through 02z
- MVFR flying and worse flying conditions are expected 02z to 11-14z
- Winds will shift from WSW to NW and N in the wake of a cold front
after 02z
Discussion:
Convective initiation has begun along and ahead of a cold front and
outflow boundaries. This supports tempo thunderstorm groups through
0z at KLAF and 02z at the other sites. The cold front will move
through this evening from northwest to southeast which will allow
the winds to shift from WSW-NW and N. A few storms could be strong
or severe with large hail the main threat. Damaging winds will also
be possible. In addition, MVFR and worse flying conditions are
expected in convection and in the wake of the cold front. Flying
conditions will improve Tuesday morning as high pressure builds in
in the wake of the front.
Best case scenario: Thunderstorms don`t hit a particular TAF site.
Worst case scenario: A strong or severe thunderstorm hit a TAF site
this evening.
&&
.IND WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Update...Eckhoff
Short Term...Beach
Long Term...Updike
Aviation...MK
Area Forecast Discussion
National Weather Service Louisville KY
1112 PM EDT Mon May 8 2023
.Forecast Update...
Issued at 1112 PM EDT Mon May 8 2023
A cold front just north of the Ohio River will continue to sink
southward overnight, reaching the Tennessee border by morning. We`ll
be under the right entrance region of the upper jet with a slightly
strengthening west to east low level jet over southern Kentucky.
Although there hasn`t been much convection in central Kentucky so
far, with precipitable water values around 1.50" and plenty of
instability plus forcing ahead of the front, additional development
is expected, primarily over the southern half of the Commonwealth.
At the time of this writing, radar scans above 0.5 are showing cells
developing from the current storm in Ohio County all the way east to
Casey County.
BNA ACARS soundings have been showing some warmth aloft. Both mid-
and low-level lapse rates are forecast to weaken overnight. Still,
with WBZ heights in the prime range for hail production plus
moderate deep layer shear, and noting that the supercell west of
Bowling Green has an extreme amount of lightning in it, hail may be
the main threat with storms overnight. (We just received a report of
nickel sized hail in Ohio County.) DACPE around 1000 J/kg this
evening is expected to diminish somewhat overnight, but some locally
enhanced gusts with the strongest collapsing cores will still be
possible. The storm west of Bowling Green has had a healthy meso in
it, and low level helicity suggests an isolated tornado can`t be
ruled out.
The most likely area for severe weather during the late night hours
will be from Ohio to Grayson to Hart Counties and points south to
the Tennessee line. Over the next 1-2 hours WoFS has been
particularly zeroing in on Edmonson County (Mammoth Cave) and nearby
counties.
&&
.Short Term...(This evening through Tuesday)
Issued at 340 PM EDT Mon May 8 2023
The rest of the afternoon is expected to be quiet across southern
Indiana and central Kentucky, but convection has already initiated
over southern Missouri ahead of an approaching cold front. In the
coming hours further development is expected. Mid/upper level flow
will push the storms east-southeast. MLCAPE value up to 2,000 J/ kg
are expected to extend east to roughly the US 127 area in Kentucky.
Deep layer shear to and just above 40 knots is also expected in this
same general area. Satellite imagery also shows this region is
currently receiving lots of sunshine. This is helping to steepen low
level lapse rates while increasing instability. Further and quicker
development is expected in the coming hour or two. While the storms
are isolated, dry mid levels and rotating updrafts will help produce
hail and gusty winds, but as more storms develop, they are expected
to becoming clusters and linear. By the time the line reaches
southern Indiana and central Kentucky, a developed cold pool will
likely cause the southern part of the line to dive farther south. The
setting sun will also begin to reduce near surface lapse rates and
lower instability. Wind profiles will also see less backing at the
surface as near surface winds become more unidirectional. This will
help reduce the limited tornado risk as the storms move east.
Convection will likely arriving in southern Indiana during the 21-
23z time range and be near the river near 0z. This is using the HREF
which shows an overall good agreement between the CAM members. Most
of the convection is expected to be out of the CWA just after
midnight.
Behind the front, winds will begin veering towards the north. By
12z, 5-10 mph winds will be out of the north or northwest over most
of the region. A few gusts near 15 mph will be possible. For the
rest of the day, high pressure moving into the Lower Ohio Valley
will help mostly sunny skies return by the afternoon, but CAA is
expected to limit temperatures to the 70s throughout the CWA.
.Long Term...(Tuesday night through Monday)
Issued at 245 PM EDT Mon May 8 2023
Dry and mild spring weather is on tap through the middle of the
week, with sfc high pressure over the Great Lakes keeping a
northeasterly low-level flow into the Ohio Valley. From Thursday
onward, the pattern turns a little more unsettled as upper trofiness
develops over the Red River Valley and starts to pinch off the ridge
axis overhead.
By late Thursday the low-level return flow starts to draw
increasingly warm and moist air into the Ohio Valley, and a sfc
front will meander over the area through the weekend as the upper
ridging breaks down. PWATs will exceed 1.5 inches, with plenty of
instability but weak shear. Timing any upper impulses will be
difficult at best, but overall expect diurnally driven chances for
showers and storms, with mainly the typical pulse severe threats of
gusty to locally damaging winds and localized flooding in play.
Temperatures will run above normal through the period, especially at
night, with a muggy early summertime feel developing.
&&
.Aviation...(00Z TAF Issuance)
Issued at 731 PM EDT Mon May 8 2023
Things are currently quiet and VFR at the TAF sites, with variable
mid level clouds and a steady SW surface wind. Expecting convective
coverage to ramp up through the evening, and have given the best
expected timing for BWG where brief IFR vis is possible in heavier
thunderstorms. Elsewhere, feel our three northern TAF sites
(HNB/SDF/LEX) may miss out on most of the coverage so have elected
to only mention VCTS for best window for now.
Cold front will drop through as storm chances diminish, with wind
quickly going NW to N and then NE by tomorrow. Low ceilings in the
MVFR range are also expected in the post-frontal period, lasting
until around late morning/midday before improvement.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Update...13
Short Term...KDW
Long Term...RAS
Aviation...BJS