Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 06/29/22

Area Forecast Discussion

National Weather Service Indianapolis IN

 949 PM EDT Tue Jun 28 2022

.Forecast Update...
Issued at 948 PM EDT Tue Jun 28 2022

Current surface analysis reveals a broadening area of high pressure
stretching from the Central Plains up into New York and
Pennsylvania. This feature is presently centered to the SE in
southern Ohio, and as it ejects eastward, winds across the CWA
should shift into a more uniform southwesterly flow than the
variable directions currently being observed. In accordance with
their proximity to the center of the quite broad high, the magnitude
of wind speeds in southern portions of the CWA is likely to be
lower; winds grids were adjusted in accordance with this. Even in
the northern counties, wind speeds are not expected to be
particularly potent through the evening, but the directional
adjustment may be slightly more noticeable there.

With very weak surface flow, minimal temperature advection will
occur. This combined with a lack of forecast cloud cover supports
substantial radiative cooling overnight, and temperatures should dip
into the mid to upper 50s. BUFKIT forecast soundings indicate a
strong surface inversion tomorrow morning, further supporting
current thinking in regards to min temp forecasts. Likewise,
dewpoints remain very dry tonight. With northwesterly flow aloft and
subsidence overhead, it appears that the Indianapolis CWA is in for
yet another cool, clear, and dry night, and thus the forecast
remains in excellent shape.

&&

.Short Term...(This evening through Wednesday night)
Issued at 244 PM EDT Tue Jun 28 2022

- Dry and warming weather through Wednesday Night

Surface analysis early this afternoon shows broad high pressure
centered over Central Indiana and southern Illinois. The high
stretched from NY/PA to KS/OK. A weak upper level disturbance was
found streaming some high cloud across Srn IL and Srn IN. Water
Vapor imagery showed mainly NW flow still in place across Central
Indiana along with subsidence across the northern parts of the
state. Light and variable surface flow was found in place across
central Indiana with dew point temps in the 40s, making for very
comfortable conditions.

Tonight -

Northwest flow aloft is suggested to persist tonight and no
forcing dynamics will be present. Meanwhile the large surface high
will remain dominant across Central Indiana as its center slowly
drifts east. This will result in continued light and variable
winds overnight, along with mostly clear skies. The only caveat is
the departing weak upper wave over southern Indiana that is
expected to continue to progress south and east. Thus a few more
clouds, mainly this evening, will be expected across the southern
parts of the forecast area. Warm air advection begins tonight with
850mb temps rising to near 13C. However, very dry dew points in
the 40s are in place. Thus will aim for lows in the mid 50s,
perhaps slightly warmer in the urban heat island of IND.

Wednesday and Wednesday Night -

Little change is expected within the overall pattern. Northwest flow
continues aloft with no forcing dynamics. Forecast soundings and
time heights show a dry column with convective temperatures that are
unreachable. By Wednesday Night, the surface high drifts to the
middle Atlantic States, allowing the full development of warmer and
more humid southerly gulf flow into the Ohio Valley. Thus with
little forcing and Indiana really still under the influence of the
strong and broad high pressure system, a mostly sunny Wednesday and
mostly clear Wednesday Night will be expected. Temperatures will be
a bit warmer on Wednesday and Wednesday Night with highs in the low
to mid 80s and lows in the mid 60s respectively.

&&

.Long Term...(Thursday through Tuesday)
Issued at 244 PM EDT Tue Jun 28 2022

* Next chance for storms arrives by the end of the week

* Temperatures remain at or above normal through the extended period

* Low confidence forecast by next week; but the potential is there
  for an increased storm threat

Progressive weather pattern for this time of year takes shape across
the northern half of the CONUS as multiple waves ride along the jet
stream. Overall upper pattern setting up this summer features a mean
ridge across the Plains and West while mean troughing persists
across the Northeast CONUS and eastern Canada. While ridging
temporally builds eastward over the Midwest, the pattern has been
for waves riding the jet to suppress the eastern portion of the
ridge, allowing it to retrograde and/or rebuild back west. Similar
type of set up occurs during the extended period as we head into
July.

The period begins with a broad, yet flat ridge stretching across the
country, while impulses rotate about a mean upper low across north
central Canada. An impulse riding along the jet stream phases with a
secondary wave rotating about the Canadian low, leading to weak
troughing developing over the Northeast and ridging rebuilding out
west this weekend. This pattern places the Ohio Valley and Great
Lakes region in another northwest flow pattern which could persist
for a few days before the western ridge shifts east across the
Plains and Midwest by the middle of next week.

...Thursday...

Southerly return flow, ahead of an approaching low in the Northern
Plains, continues to advect in a warmer and more moist airmass on
Thursday. Temperatures aloft at 850 mb rise from around 13C the
previous day to almost 20C by Thursday evening, supporting high
temperatures much warmer than what they have been this week. Highs
exceeding the 90 degree mark look likely Thursday across Central
Indiana. While southerly flow pumps in a warmer and moist airmass,
BUFKIT soundings indicate the possibility of mixing during the
afternoon into a much drier layer aloft. Expect dew points to
gradually rise early Thursday to near 60 degrees; however if mixing
occurs high enough, the rate at which humidity levels rise during
the afternoon may slow down. Although after sunset, still expect dew
points to surge to near 70 by Friday morning. Despite being in the
warm sector of the approaching system, subsidence under the high to
the east keeps conditions dry for the moment as all the forcing and
energy for storms remains well to the north.

...Friday - Saturday...

As mentioned above, ridging over the Midwest won`t last long in this
weather pattern as the next impulse in the jet stream works to
suppress the ridge and dig a weak trough over the north and east. At
the surface, a trailing cold front from the low in Canada sags
southward and approaches the region from the north on Friday. This
front is not very impressive as it continues to weaken and becomes
more east-west oriented as it travels further away from upper level
support and its parent low occludes.

Uncertainty still remains regarding specific details of the front,
where it may stall, and the coverage of storms along it. With little
forcing and upper level support, do not expect a widespread severe
weather outbreak. A hot, humid airmass south of the front will
however support pulse thunderstorms during the peak heating of the
day which could merge together into a line. Confidence will increase
in the finer details closer to the event, especially with the help
of CAMS guidance. Overall not too concerned with the severe weather
threat; however a severe storm or two is not out of the question.

Models disagree with the speed and timing of the front, which could
have big impacts on sensible weather during the first half of the
weekend. With the possibility of the front lingering across Indiana
through Saturday, the potential is there for clouds and storms to
stick around. If the front pushes right through, Saturday will be
drier with potential clearing as everything exits to the south and
east. Will also need to watch for the potential of waves/areas of
more organized convection forming along the front, keeping it from
progressing southward and increasing the storm threat locally.
Something to note, both EC and GFS ensembles have a less than a 10-
20% chance of more than 1 inch of QPE and less than a 50% chance of
more than 1/2 inch of QPE through Sunday morning. Ensembles keep the
probability of heaviest precipitation across the southern 1/3 of
Indiana through the weekend. Highest confidence remains across the
southern portion of the forecast area for showers and storms this
weekend.

Overall, expect a hot and humid day ahead of the front Friday as
southwesterly flow continues to advect in a tropical airmass from
the Gulf. Highs approaching 90 look increasingly likely once again;
however timing and coverage of storms could affect max temperatures.
This will be something to monitor over the next couple days. With
the likelihood of increased clouds and precipitation around, keeping
highs lower on Saturday in the mid 80s; however cloud and storm
coverage will significantly affect highs overall. There isn`t much
cold air behind the front, so any clearing on Saturday could allow
for warm air aloft to mix down and support high temperatures closer
to 90 degrees. For this reason, confidence remains low on the
forecast highs as well.

...Sunday - Early Next Week...

Northwest flow pattern sets up Sunday and persists into the first
half of next week before ridging begins to build back east again.
Guidance disagrees with how far east the western ridge builds and
the placement of lows and fronts; which could significantly impact
weather conditions across the state. However if more of a northwest
flow pattern does persist, potential is there for convective storm
complexes to form in the Plains then ride the jet stream
southeastward into Indiana as some models suggest. Keeping chance
wording for PoPs Sunday through early next week to account for the
lower confidence in the placement of mesoscale and synoptic features
and the possibility of MCS`s impacting the region. Aside from the
storm chances, this type of pattern supports temperatures at or
above normal in the mid 80s to near 90 degrees with higher humidity
levels. However, daytime highs could be significantly impacted on
any given day by storms and increased cloud cover from thunderstorms
across the region. With all this being said, low confidence exists
in the extended range forecast.

&&

.Aviation...(00Z TAF Issuance)
Issued at 744 PM EDT Tue Jun 28 2022

IMPACTS:

- VFR conditions will prevail thru current 00z TAF period

Discussion:

Some afternoon diurnally driven cumulus clouds have developed with
bases around 6kft agl across the Northwest Indiana airfields, but
expect as sunset approaches these clouds will quickly depart to
mostly clear skies. Further north is a frontal boundary that is
slowly sliding south, but it is expected this will not produce any
thick cloud decks for Central Indiana airfields during current TAF
period; however, there may be some high bases that develop midday
Wednesday.

Winds will continue to be very light to at times variable from the
north to northwest at or around 4kt or less, which shouldn`t pose
any impacts to smaller aircraft this evening. Making it optimal
flying conditions. Winds during the day Wednesday may begin to
increase slightly from the southwest around 6-8kt.


&&

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

$$

Update...Marcus
Short Term...Puma
Long Term...CM
Aviation...Beach