Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 03/03/23
Area Forecast Discussion
National Weather Service Houston/Galveston TX
548 PM CST Thu Mar 2 2023
...New AVIATION...
.SHORT TERM...
(This evening through Friday Night)
Issued at 352 PM CST Thu Mar 2 2023
So far this afternoon, capping is holding strong - and as a
result, only a handful of weak showers have been seen across the
area today. ACARS soundings as well as the 18Z soundings at FWD
and CRP imply pretty strongly that the cap is strong enough to
hold for some time in our area, though the lack of upper air data
in our north, where severe potential is the greatest is a bit of a
concern. Fortunately, that will change at 21Z when the TAMU
meteorology folks will have a balloon up. I suspect that the cap
will be quite operational when our friend (the balloon) arrives.
So...when does that change? Well, it may be some time...it might
not meaningfully change until we are in a post-frontal
environment. The warm front is already well up into North and
Northeast Texas where a new mesoscale discussion has gone up, and
the cap is just so strong, that there`s a good chance that we
won`t be able to defeat it until the mechanical forcing of the
cold front - or rather, the QLCS leading it - makes its way into
the area from Central Texas. This shouldn`t happen until 02Z or
so.
Once we get to that point, we`ll have to see how healthy an
updraft can be once it is forced into an environment much more
supportive of deep convection. Because above this cap, there is a
deep well of instability to tap into with steep midlevel lapse
rates. But...I`ve seen more than once that updrafts are so
disrupted that they`re simply unable to take advantage of this
environment, leaving only more anemic showers and storms. This
seems most likely to happen in our southwest around Matagorda Bay,
where numerical guidance has pretty strong agreement in nothing
more than a broken line of showers moving through this area. The
farther north and east you head, the better a chance we`ll see of
getting a stronger to severe storm.
Ultimately, I think the guidance is on the right track in showing
that the focus of this event will be north of our area, and if the
southern fringes of the strongest core of storms manages to dip
into our area, it will be in the northern third or so of our area
(think places like B/CS, Huntsville, Crockett, etc.) Even then,
I`d say our chances are pretty limited - with such a highly
conditional environment where the monster cap needs to be defeated
before we can even start talking about a storm becoming severe,
we`re probably only looking at a small handful of storms at most
getting into this discussion.
Expect the line to exit stage right an hour or two after midnight.
In the post-frontal environment, look for gusty west to northwest
winds to develop as a cooler, drier airmass surges into the area.
We won`t have a ton of time for temps to fall before sunrise, but
lows in the upper 40s in the north to the middle 50s at the coast
can be expected. Highs tomorrow should be notably cooler than
today - not an 80 degree high to be seen in the area. That said,
a sunny sky with dry air should warm up pretty effectively, so I
still have highs in the middle 60s to middle 70s in the forecast.
Winds should also begin to diminish later in the morning and into
the afternoon.
Finally, tomorrow night should again cool off effectively, and
with a fully night to chill out, we should see lows drop farther
into the 40s up north, and below 50 for all but the immediate
coast.
&&
.LONG TERM...
(Saturday through next Wednesday)
Issued at 352 PM CST Thu Mar 2 2023
No changes to the dry/quiet forecast on tap for the weekend. A flat
almost zonal ridge aloft combined with an eastward exiting surface
high will help to maintain this mild air mass over SE TX with day-
time highs in the upper 70s to lower 80s. Overnight lows should be
in the 50s and 60s. As the surface high shifts further east, winds
from the SE will be more established by Mon with temperatures war-
ming into the mid 80s for Mon/Tues. These latest 12Z runs have not
been as aggressive with the return of low-level moisture/POPs dur-
ing the late Mon/Tues period as the next front seems to be slower.
For now, the better rain chances should be Weds/Thurs as this next
cold front moves south through the CWA.
&&
.AVIATION...
(00Z TAF Issuance)
Issued at 548 PM CST Thu Mar 2 2023
Periods of -RA/-SHRA are possible through early this evening before
the currently located central Texas line of strong to severe SHRA/
TSRA moves across CLL (around 03Z or so) and races eastward across
the rest of the area and then off the coast around 06Z. Storms along
the front could be strong/severe. Gusty S to SW winds ahead of the
front/storms will shift to the W and NW and remain gusty behind the
front. MVFR/IFR ceilings ahead of the boundary this evening will
become VFR with skies eventually clearing out behind the boundary
late tonight.
Tomorrow`s gusty WNW to NW winds in the morning will gradually weaken
as the afternoon progresses. VFR tomorrow evening with light winds.
42
&&
.MARINE...
Issued at 352 PM CST Thu Mar 2 2023
Strong gusty onshore winds will remain in the forecast into the eve-
ning hours ahead of the next cold front. A Small Craft Advisory does
look reasonable for our bays/coastal waters tonight through tomorrow
for both before and after this front. Moderate to strong north winds
are expected in the wake of this line overnight through late morning
or early afternoon Fri. So, this along with already low astronomical
tides could produce abnormally low tides on Fri with low tide Friday
morning around 1ft below Mean Low Lower Water.
Light NE/E winds are expected Fri night/Sat with SE winds likely re-
turning by Sun...persisting through much of next week. Extended out-
look as the next cold front tentatively scheduled for next Thurs.
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 49 68 46 76 / 90 0 0 0
Houston (IAH) 53 73 51 79 / 70 10 0 0
Galveston (GLS) 58 72 59 70 / 50 0 0 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk until 6 PM CST this evening for TXZ436>439.
GM...Small Craft Advisory until 10 AM CST Friday for GMZ330-335-350-
355-370-375.
&&
$$
Area Forecast Discussion
National Weather Service Indianapolis IN
1014 PM EST Thu Mar 2 2023
.Forecast Update...
Issued at 1014 PM EST Thu Mar 2 2023
A thickening cloud shield has encompassed the region this evening
with the onset of light rain showers quickly approaching the lower
Wabash Valley. 0230Z temperatures ranged from the upper 30s to the
mid 40s from north to south across central Indiana.
The current forecast is on point for the rest of the night as rain
will expand into the forecast area from the southwest mainly after
midnight. LAPS and ACARS soundings still show a fairly stout dry
layer present below 650-700mb. With more extensive isentropic lift
not expected to build into the region until after 06Z...rain should
largely remain light and focus primarily over the lower Wabash
Valley and south central Indiana for the next 3-5 hours as the
airmass slowly saturates from the top down. With more extensive lift
and the arrival of the low level jet during the predawn hours as the
warm front lifts north into the lower Ohio Valley...widespread rain
will expand north across much of the forecast area by shortly after
daybreak.
The greatest impacts with the heaviest rainfall will come just prior
to daybreak across our southwest counties...then focus across the
region on Friday with strong gradient wind gusts as the intense
surface low lifts into the Ohio Valley by the afternoon. Newest
model trends continue to support the potential for widespread 2 to 3
inch rainfall totals across the forecast area with highest amounts
focused across the southwest half of the forecast area. Any embedded
convection will produce localized areas with even higher totals as
well.
There remains a risk for some severe weather during the late morning
through mid afternoon focused primarily across south central Indiana
as the frontal boundary moves quickly across the region. The best
instability remains anchored near and south of the Ohio River with
the focus for more widespread severe weather in those areas. That
being said...the track of the surface low across southern Indiana
with large amounts of shear and SRH values do support the potential
for isolated damaging winds with convection as winds near 50kts will
be just 2-3kft off the ground. The presence of a shallow inversion
may serve as a mitigating factor for more widespread stronger
convective gusts.
And as if this is not enough...recent model trends are attempting to
pull colder air into the northern Wabash Valley a touch faster late
Friday afternoon as a strong deformation band pivots around the back
side of the surface low. The overall setup remains sloppy with near
surface temperatures in the mid to upper 30s and the deeper
dendritic growth zone will likely remain just to our northwest...but
there is enough of a trend to introduce snow mixing with rain over
northwest counties after 21Z. This could bring a slushy...wet light
accum into the evening in these areas before precip tapers off. Will
continue to monitor these trends closely.
Zone and grid updates out.
&&
.Short Term...(This evening through Friday night)
Issued at 248 PM EST Thu Mar 2 2023
...Heavy Rain Potential Later Tonight into Friday...
...Windy Conditions at Times Friday...
Key Messages:
* Flood Watch continues for all of Central Indiana but start time
delayed in north
* Widespread rain will move into the area from the south overnight
and continue on Friday. Rainfall amounts over 2 inches are
possible.
* Potential for strong wind gusts at times Friday, with some strong
to severe thunderstorms across mainly southern areas
Rest of this afternoon into this evening...
Quiet conditions will persist during this period with high pressure
still in control. Clouds will be on the increase.
Overnight...
An upper trough will move into Arkansas with a potent surface low
not too far to the northeast. Ahead of these, a 50-60kt southerly
low level jet will develop ahead of this and pump in plentiful
moisture. Isentropic lift will ramp up with the low level jet. This
will result in rain spreading north across much of the area by 12Z.
Will go likely or higher PoPs most areas by 12Z.
Highest moisture transport will reach the southern forecast area by
late in the night so that`s where the best threat for heavy rain
would be tonight. Based on the expected arrival of heavier rain,
have delayed the start of the flood watch in the north until 12Z.
Friday...
An upper low will move into northern Indiana while the surface low
will begin to occlude and move into central Indiana. The surface low
will be quite deep (around 980mb).
Integrated vapor transport progs show very strong transport of
moisture (near the 99th percentile) into the area thanks to the
continued low level jet. In addition to the broad forcing with this
system, good frontogenetical forcing will be present as well during
the first half of the day. Thus, heavy rain will continue to be a
threat. Will continue the flood watch for all areas.
Very strong winds will remain not far off the surface on Friday. The
question is then how much of these can mix down to the surface. Warm
air will be brought in aloft and could inhibit mixing. However, some
showers could mix down brief periods of stronger winds.
Questions remain on how far north the warm sector will get. Some
models are keeping the surface low farther south and thus the warm
sector only in the far southern portions of the area. However, the
system may become negatively titled, which favors a more northern
warm sector. At the moment, believe this latter scenario is the most
likely, but confidence is not as high as would prefer this close to
the event.
In the warm sector, winds will mix down easier and could get to
advisory criteria. Also, the strength of the surface low also lends
to stronger winds being possible. Will err on side of caution and go
with a Wind Advisory for Friday given the above.
Within the warm sector, a few strong to perhaps severe thunderstorms
could develop, as again, it wouldn`t take much to get the strong
winds down to the surface. The Storm Prediction Center has placed
much of the area in a risk for severe storms, which looks reasonable
given the above.
Temperatures will depend on where the warm sector gets. Will go
lower 40s north to upper 50s south.
Friday night...
The system will exit the area to the northeast during this time.
Precipitation will still be likely northeast at the start of the
period, with lesser chances southwest as the system exits. Colder
air will work in behind the low and could turn the lingering
precipitation into some snow in the northwest. However, by the time
that occurs precipitation amounts and rates will be low, so not
expecting much if any accumulation.
Winds will continue to be gusty behind the low thanks to cold
advection and the pressure gradient. Will have the advisory go until
03Z.
&&
.Long Term...(Saturday through Thursday)
Issued at 248 PM EST Thu Mar 2 2023
* Primarily dry and warming through the week into Monday, with
temperatures moderating thereafter.
* Minor chances for precipitation next work week, no significant
weather impacts anticipated beyond ongoing flooding from short
term rainfall.
Once the strong low impacting the area in the short term exits the
region, flow aloft over much of the CONUS will become quasizonal,
with low amplitude disturbances sliding through fairly fast upper
level flow over primarily the northern CONUS as the new work week
unfolds. The pattern begins to amplify very late in the period which
may lead to more significant variation in temperatures.
Surface high pressure will keep the area dry through the weekend
with temperatures gradually warming as heights rise in the wake
of the anomalously strong low exiting the area.
The first weak disturbance slides quickly to our northwest early in
the work week, and will necessitate low shower chances Monday
afternoon and evening. Moisture concerns are paramount with this
system as some models keep the Gulf closed off and significantly
limits moisture return, so any precipitation that does occur will
very likely be light.
As the work week unfolds, model differences increase in speed and
positioning of systems, which is typical with amplifying patterns.
Will stick mostly with NBM slight chances at times Tuesday night
into Wednesday night owing to this uncertainty. There is some chance
that light snowfall could occur midweek were the faster Euro to
verify, but typically a slower progression is best with amplified
flow, and given the fairly consistent anomalous warmth recently,
impactful wintry precipitation is going to be tough to come by
without a very strong system at the proper time in the diurnal cycle.
The primary impact of concern for the long term will be the
progression and hopefully recession of any flooding that continues
and/or develops as a result of the short term significant rainfall.
&&
.Aviation...(00Z TAF Issuance)
Issued at 611 PM EST Thu Mar 2 2023
Impacts:
* VFR this evening then deteriorating conditions overnight as rain
spreads north
* Steady rain late tonight through mid afternoon Friday with locally
heavy rainfall and thunder
* IFR and lower conditions developing Friday morning and persisting
for much of the day
* Winds increasing overnight and Friday with peak gusts to 30-35kts
on Friday
Discussion:
Poor flying conditions will develop across central Indiana beginning
late tonight and continuing throughout the day Friday as an intense
surface low tracks across the region.
Clouds will steadily increase through the evening with rain
expanding into the area near or after midnight. Rain will overspread
the terminals from south to north late tonight through daybreak
Friday...with IFR conditions developing throughout the morning. The
heaviest rainfall will occur from just prior to daybreak through mid
afternoon as a strong low pressure approaches from the southwest.
Potential exists for a band of heavier rain and embedded
thunderstorms along a frontal boundary set to track through the area
early to mid afternoon Friday. Showers will become more scattered
late afternoon into the evening once the front passes.
Winds will increase late tonight into Friday with gusts routinely
peaking at 30-35kts if not briefly higher during the day Friday. The
wind direction will be predominantly easterly tonight through midday
Friday with a shift to N/NW by late day once the surface low passes
through the region and into northwest Ohio during the evening.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
Flood Watch from 7 AM EST Friday through late Friday night for
INZ021-028>031-035>042-049.
Wind Advisory from 10 AM to 10 PM EST Friday for INZ021-028>031-
035>049-051>057-060>065-067>072.
Flood Watch through late Friday night for INZ043>048-051>057-
060>065-067>072.
&&
$$
Update...Ryan
Short Term...50
Long Term...Nield
Aviation...Ryan