Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 08/11/22

Area Forecast Discussion

National Weather Service Indianapolis IN

 1136 PM EDT Wed Aug 10 2022

...Updated Aviation Discussion...

.Forecast Update...
Issued at 952 PM EDT Wed Aug 10 2022

Forecast is in good shape this evening. Much of the cumulus field
has dissipated, but some lower clouds were hanging around the far
southern forecast area as expected. Tweaked sky cover based on
latest satellite images, but no big changes were made.

Some patchy ground fog may develop near sunrise with mostly clear
skies and light winds, but confidence just isn`t high enough to add
to the forecast at this time.

Otherwise just tweaked temperatures as needed.

&&

.Short Term...(This evening through Thursday night)
Issued at 224 PM EDT Wed Aug 10 2022

* Seasonable high temperatures in the low 80s

* An isolated shower possible Thursday

Mean troughing pattern over the Great Lakes and Northeast developing
midweek will keep conditions relatively calm with seasonable
temperatures in the short term. While a strong upper ridge persists
over the Western CONUS, a 100 kt jet streak over Southern
Manitoba/Ontario will dive southeast deepening the trough over the
region and placing Indiana solidly within northerly upper flow. At
the surface, a large area of high pressure extends from Central
Canadian Prairies southeast towards the Ohio Valley. High pressure
will continue to sink southward through the period while a very weak
cold front extending from a low in the Hudson Bay pushes through on
Thursday. High pressure maintains its influence over Indiana
through the end of the week, becoming centered over Michigan by
Friday.

...This Evening and Tonight...

Original front responsible for active weather earlier this week
still remains close enough to the region to have a few affects on
the overall weather. The front continues to very slowly push south
of the Ohio River while dry air lags behind to the north. As high
pressure settles over the region, a weak inversion evident on IND
ACARS soundings will work to keep low level moisture in the PBL
through the day and into the evening hours, especially closer the
front. Thickest cloud cover remains across portions of South Central
Indiana, while North Central Indiana has been able to dry out and
clear out during the day. As the inversion tonight redevelops and
strengthens, would not be surprised to see the development of low
clouds and patchy fog again, especially across far South Central
Indiana where low level moisture is more abundant.

Due to a potential gradient in cloud cover overnight, it is
reasonable to forecast low temperatures a few degrees warmer across
the south than areas further north under clear skies. Areas along
and north of the I-70 corridor have the best chance at clearing out
with lows potentially dropping into the upper 50s!

..Thursday...

High pressure continues to settle in from the north across the Great
Lakes and Ohio Valley. A very weak front extending from a low around
Northern Quebec to the Great Lakes will slide southward during the
day tomorrow with very little moisture associated with it. While
subsidence from high pressure over the region works to suppress
convection along the front and advect drier air in, there may be
just enough lift along the front and with the approaching exit
region of a 90 kt jet that a few showers could develop Thursday
afternoon around 16z-00z. Hi-res forecast soundings also show steep
lapse rates, low amounts of CAPE (500-1000j/kg), and effective bulk
shear 30-40 kt which could support a brief thundershower; however
organized convection is not expected. Outside of any shower, expect
partly to mostly cloudy skies as the front moves through followed by
a clearing trend during the evening hours.

Temperatures are expected to remain around seasonal norms in the low
to mid 80s across Central Indiana. Any area that gets a shower
tomorrow may struggle to reach the 80 degree mark.

&&

.Long Term...(Friday through Wednesday)
Issued at 224 PM EDT Wed Aug 10 2022

An amplifying upper level pattern is expected during the long term,
with a central/western US ridge and eastern US trough/potentially
closed low both strengthening as the period wears on into next week.
This should result in somewhat milder than normal conditions for the
time of year and largely quiet weather with the area likely stuck
between the two systems, although some low pops will be merited late
in the weekend for some showers and isolated thunderstorms as a weak
upper wave cresting the ridge drops into the western Great
Lakes/Ohio Valley.

Much of the rest of the period, the bulk of the guidance keeps a
closed or nearly closed upper level low off to our east with
northwest flow aloft and the amplifying ridge to our west. Subtle
shifts in this pattern to the east could mean warmer and drier
conditions or cooler and wetter conditions with western shifts.

&&

.Aviation...(06Z TAF Issuance)
Issued at 1136 PM EDT Wed Aug 10 2022

Impacts:

* Low probability of patchy ground fog overnight.
* Isolated convection Thursday afternoon.

Discussion:

A few VFR stratocumulus may linger into the morning hours. With
light winds and mostly clear skies overnight, there is a low chance
for some patchy ground fog, but odds remain too low to mention in
the TAFs.

A weak front will move north to south across the sites Thursday
afternoon, bringing a few hour period of VFR ceilings along with
isolated convection. Used a VCSH mention for now.

Winds will remain less than 10kt for much of the period, but
wouldn`t be surprised for a few gusts after the front passes
Thursday afternoon.

&&

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

$$

Update...50
Short Term...CM
Long Term...Nield
Aviation...50