Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 06/28/22

Area Forecast Discussion

National Weather Service Indianapolis IN

 1100 PM EDT Mon Jun 27 2022

...Updated Aviation Discussion...

.Forecast Update...
Issued at 953 PM EDT Mon Jun 27 2022

Surface analysis confirms that a potent high pressure has advanced
slightly eastward into Missouri, leaving Indiana in weak
northwesterly flow for the near term. Amidst this HP-driven NW flow,
a cooler and drier continental airmass continues to slowly seep
south from Canada.

Upper-level water vapor imagery and visible/IR satellite reveal a
canopy of clouds over the central Plains. This cloud coverage is
associated with a shortwave centered over Kansas, and the deck will
push eastward towards the CWA as the night progresses. The shortwave
feature and its better forcing should remain displaced to the south,
but as the aforementioned high advects eastward, upper level flow
picks up more of a westerly component. These westerly winds aloft
will blow some of the upper-level clouds into Indiana, and forecast
soundings collectively agree that high clouds should enter Indiana
in the next few hours. Because of this trend, sky coverage grids
were bumped upwards from previous thinking. With this being said,
ACARS soundings show a dry column through the mid levels that will
prohibit any precipitation from reaching the surface overnight.
These upper clouds may limit overnight cooling, and minimum
temperatures were adjusted upwards in accordance with this line of
thought.

&&

.Short Term...(This evening through Tuesday night)
Issued at 231 PM EDT Mon Jun 27 2022

- Dry and warming weather through Tuesday Night

Surface analysis early this afternoon shows strong high pressure in
place over Eastern NB and eastern KS extending east into IL and
Indiana. Cooler and less humid air was flowing into Indiana on
northwest winds ahead of the high. Yesterday’s frontal boundary had
pushed well to the southeast, stretching from SE NY to Eastern PA
continuing south to points just east of the Appalachians. GOES16
shows mostly clear skies across Central Indiana as well as points
upstream across the upper midwest. Water vapor imagery shows strong
subsidence and drying in place across Illinois and Indiana amid NW
flow stretching the NW plains to the Ohio Valley.

Tonight...

Models show northwest flow remaining in place aloft with no forcing
dynamics passing. The surface high to the west of Indiana is
expected to advect eastward, reaching Indiana and expanding all the
while. By Tuesday morning the high is suggested to stretch from
western PA across Indiana to the southern plains. Forecast soundings
and time heights show a dry column. Thus mostly clear skies will be
expected. Minimal temperature advection is shown by the models as
north winds become light and variable through the night. Dew points
across the area have mixed to the mid 40s. Thus no fog will be
expected along with lows in the lower 50s.

Tuesday...

Little change in the overall pattern. The northwest flow aloft is
suggested to flatten a bit, however there are still no signs of any
forcing dynamics. The strong and large area of surface high pressure
is expected to be in place across Indiana through the day but
gradually drift to Ohio by the late afternoon. Forecast soundings
continue to show a dry column with unreachable convective
temperatures. Thus another mostly sunny day is expected. With
minimal temperature advection expected through the day will trend
highs toward or slightly above persistence, with upper 70s to around
80.

Tuesday Night...

Northwest flow aloft is suggested to redevelop on Tuesday night but
again no forcing dynamics will be present. The surface high will
have pushed east of Indiana…allowing the beginning of warmer and
more humid southerly flow to develop. The impact of this will not be
in the skies as clear skies will continue to be suggested, but with
warmer temperatures overnight. Warm air advection from the west is
shown by the models with 850mb temps rising to near 13C. Thus will
expect warmer lows on Tuesday Night in the upper 50s.

&&

.Long Term...(Wednesday through Monday)
Issued at 231 PM EDT Mon Jun 27 2022

Highlights:

* Dry, but warming trend mid week. Highs in the upper 80s to low
  90s.
* Rain chances return Friday; peaking over the weekend associated
  with a frontal passage.

Wednesday and Thursday

West to east WAA upstream of a ridge will continue to build low
level pressure further reinforcing the dry conditions over central
Indiana. This will simultaneously push temperatures back above
normal for late June, with highs in the upper 80s Wednesday and
even low 90s by Thursday. Model ensemble members are on in
agreement this high will remain throughout Thursday, leading to
high confidence in no precipitation for the remainder of June.

Friday through Sunday

High pressure moves off to the east beginning Thursday night into
Friday, associated with an eastward moving pressure trough.
Throughout Friday, warm southerly flow will aid in moisture return,
with a few showers possible along broad isentropic lift. The more
confined lift comes through late Friday into Saturday due to an
advancing frontal boundary. The parent low looks to occlude, leaving
the boundary significantly displaced from the upper level system.
This leads to lots of uncertainty heading into the weekend on precip
timing and the amount of rain expected.

Temperatures will be rather warm Friday as moisture returns from the
south. Afternoon highs will be similar to Thursday, but with dew
points increasing, apparent temperatures will be much higher;
approaching 100. By the weekend, extensive cloud cover along the
aforementioned boundary will limit temperature gains. Still, expect
highs in the mid 80s with muggy dew points near 70.

&&

.Aviation...(06Z TAF Issuance)
Issued at 1100 PM EDT Mon Jun 27 2022

IMPACTS:

- VFR conditions expected through the TAF period with high
  confidence.

Discussion:

High pressure and a dry column will result in VFR flying conditions
over the terminals through Tuesday evening and beyond. Winds will be
very light to calm.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

Update...Melo/Marcus
Short Term...Puma
Long Term...Updike
Aviation...MK



Area Forecast Discussion

National Weather Service Phoenix AZ

 503 PM MST Mon Jun 27 2022


.UPDATE...Updated Aviation Discussion.

&&

.SYNOPSIS...
Daily shower and thunderstorm chances will persist much of the week
with the better coverage focused over higher terrain locations north
and east of Phoenix as moisture remains locked over the region.
Storms mat occasionally progress into valley locations with
Wednesday afternoon and evening appearing to be the more likely time
frame for impact to lower elevation communities. Temperatures will
remain near normal with afternoon highs across the lower deserts
exceeding 100 degrees, resulting in a moderate HeatRisk.

&&

.DISCUSSION...
Early afternoon observational datasets indicate an environment not
nearly as conducive for expansive thunderstorm activity as the past
several days. A strengthening anti-cyclone was situated over the Los
Angeles basin while TS Celia was rapidly weakening and moving
westward away from the Baja peninsula. The resulting flow was
creating shearing, deformation, and deepening subsidence over the
forecast area while 12Z KPSR and ACARS soundings depict a
convectively overturned atmosphere with weak lapse rates and minimal
potential instability.

The most robust activity this afternoon should be associated with
inverted troughing over NE Mexico supporting explosive thunderstorm
development into central Sonora. Within Arizona, HREF members
indicate a few storms along the Rim and high terrain of Yavapai
County with the lingering moisture, however given the stable
environment, outflows should not be nearly as organized, and likely
decaying as they enter the forecast area. Latest HREF probabilities
for 30kt outflow barely clips 30% into the CWA, and even this may be
overly generous. Ridge expansion into northern and central Arizona
Tuesday should provide another convectively limited scenario through
most of the forecast area. Scattered mountain storms will again be
common, however the primary forcing and moisture pool appears to be
best collocated for strong storms across far SE Arizona along the
international border. A resulting MCV floating around southern
Arizona Wednesday morning would not be an unexpected outcome from
such a storm complex.

An increase in convective coverage is likely Wednesday as the ridge
core shifts eastward into the four corners, and a better south to
southeast flow becomes established and pulls midtropospheric
moisture northward. Whether an MCV or a longer tracking shortwave,
there have been numerous and recurring hints from models that
favorable energy will propagate into the area along the western
periphery of the ridge and enhance large scale ascent. Forecast BUFR
soundings continue to indicate 9-10 g/kg mixing ratios nicely
distributed through the top of the boundary layer resulting in
little to no inhibition with MLCape near 1000 J/kg and DCape ~1500
J/kg. Mandated NBM PoPs across the lower deserts increase up to 30-
40% which even may be too low given the scenario and tell-tale
reflection in BUFR sounding data of widespread and organized
thunderstorm complexes. The entire setup is not too dissimilar from
this past weekend with impacts also expected to be similar.

Thereafter into early next week, there is quite a spread among
ensemble members with respect to how deep and far east a trough and
negative PV anomaly digs into the West Coast. A handful of members
(mostly among the EPS regime) indicate strong troughing and westerly
flow developing over much of the region dislodging moisture eastward
and eliminating storm chances. On the other end of the spectrum,
another subset of members (more so among the CMC members) keep
troughing well to the north maintaining easterly flow, deeper
moisture, and storm chances. Given averaging of the forecast through
this time frame, POPs are a compromise of these extremes and follows
a somewhat enhanced or heightened climatology look, though certainly
a bit less active than the past several days.

&&

.AVIATION...Updated at 2355Z.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Winds will favor a combination of SE-SSW components this evening
until 06-07Z when SE flow should resume through mid to late Tue
afternoon, AOB 12 kts. A mid to late Tue afternoon SSW shift is
now also favored. SE outflow winds could also increase late
tonight to early Tue with some gusts upwards of 20 kts possible.
Thunderstorms this afternoon and evening will be much less in
coverage as compared to previous days, mostly favoring the high
terrain to the north and east and southeast. There are still
10-20% storm chances in the metro and 10-30% chances for >30 kt
outflow winds, with the most probable direction being from the SE
late tonight as per the latest guidance. Skies will remain mostly
clear to occasionally partly cloudy with FEW-SCT mostly mid-high
decks from 8-25 kft.

Southeast California/Southwest Arizona including KIPL and KBLH:
Isolated storms over La Paz County later this afternoon could lead
to a wind shift at KBLH. But, confidence in that scenario is too low
to reflect in the TAF. Similarly, there is potential for isolated
storms over the mountains of San Diego County and far northern Baja
which could produce outflow that reaches KIPL. But confidence in
that scenario is even lower than for KBLH. Otherwise, winds will
favor southeasterly at KIPL and southerly to southeasterly at KBLH.
Skies will be mostly clear.

&&

.FIRE WEATHER...
Atmospheric moisture will continue abnormally high through most
districts providing nearly daily opportunities for shower and
thunderstorm activity. Higher terrain locations will experience the
best storm and wetting rain chances though lower desert communities
may occasionally join in, especially Wednesday afternoon and
evening. Minimum afternoon humidity levels values will generally
fall in a 15-30% range through trends show lower values materializing
over western districts late in the week. Overnight recovery will
range between 25-50% across the lower elevations and between 50-80%
across the higher terrain areas. Aside from occasional late
afternoon/early evening thunderstorm outflows, winds should not be a
significant impact.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&

$$

DISCUSSION...18/Lojero
AVIATION...Sawtelle/Benedict
FIRE WEATHER...Lojero/18