Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 101723

Area Forecast Discussion
National Weather Service Indianapolis IN
123 PM EDT Mon May 10 2021

...Updated Aviation Discussion...

.Forecast Update...
Issued at 945 AM EDT Mon May 10 2021

Current forecast is on track, so no changes needed.  Temperatures
around the forecast area at this time are generally in the mid 40s,
so the frost threat has ended.  Headlines were allowed to expire at
Mon 12Z.  Weak high pressure and zonal flow aloft will result in a
pleasant day across central Indiana with plenty of sunshine.  Highs
are still progged to top off in the low to mid 60s.


.Short Term...(Today through Tuesday)
Issued at 251 AM EDT Mon May 10 2021

Mainly Dry and cool weather expected through Tuesday.

Surface analysis early this morning shows low pressure over the
middle Atlantic States...dragging a cold front across Appalachia to
Tennessee. Broad and poorly organized high pressure was found over
the Canadian Plains...extending its influence across the upper
midwest to the Ohio Valley. Cool NNE surface flow was in place
across Central Indiana with dew points in the 30s. GOES16 shows
clear skies across the forecast area. Water Vapor showed deep low
pressure in place aloft over Ontario...yet mainly a zonal flow was
in place across Indiana.

Models today continue to keep the nearly zonal flow in place aloft
as the deep upper low over Ontario sags southward. High pressure to
the northwest is expected to continue to build
southeastward...continuing to provide a dry and cool flow of
Canadian air to Central Indiana. Forecast soundings remain dry with
CU development anticipated as convective temps are reached and a
thin layer of saturation is seen within the column this afternoon
with a dry inversion aloft. Thus will trend toward a becoming partly
cloudy type forecast today along with highs at or below the NBM
given the cool North flow and cold air advection.

Tonight the models suggest a short wave pivoting across Indiana
within the upper flow as the previously mentioned upper low sags
farther south...resulting in somewhat of a cyclonic flow aloft over
night. Mid levels suggest some saturation as this wave passes
overnight as do the time sections and forecast soundings. Moisture
remains a concern as pwats only reach around 0.50 inches. Lower
levels will also be unfavorable for development and also dry due to
the continental air mass in place. Thus confidence for any precip
is quite low...and should anything fall...amounts will be quite
minimal. Will trend any pops at or below the NBM...but will trend
toward a mostly cloudy type of night. The expected clouds at this
point should result in warmer low temps then the previous
forecasts...which may result in no frost. Stay tuned to see if the
models remain consistent with this approaching short wave overnight.

On Tuesday dry air looks to re-establish itself within the lower
levels as subsidence builds through the day. The previously
mentioned short wave looks to departs to east as does the previously
mentioned upper low. Meanwhile strong ridging builds aloft over the
Northern Plains...allowing strong high pressure to begin to build
across the Great Plains toward Indiana. Forecast soundings and time
heights through this time remain dry. Thus will once again trend
toward a partly cloudy Tuesday. Given the ongoing cold air advection
but plentiful sunshine...will trend lows close to the NBM.


.Long Term...(Tuesday night through Sunday)
Issued at 251 AM EDT Mon May 10 2021

...Gradual Warming Trend Expected...

A large dome of surface high pressure will be the dominant weather
feature across the area throughout the week, with dry weather
expected through at least Friday night as a result. Blended
initialization continues to want to insert some slight chance pops
on Thursday as a weak upper level wave moves through the region, but
with significant low level dry air, even if anything were able to
form given the low level subsidence, measurable precip would be
unlikely to make the ground. More likely, we`ll see an uptick in
cloud cover associated with the trough and that will be the extent
of it.

Things get a bit more messy toward the weekend as the low level
baroclinic zone begins to push back northward and one or more upper
level disturbances move into the region. Given timing and handling
differences between the various models will stick with low pops per
the NBM for showers Saturday onward.

Temperatures will gradually moderate as the week wears on, although
they will still be largely below normal at least until the very end
of the period. Blend handled this well.


.Aviation...(18Z TAF Issuance)
Issued at 123 PM EDT Mon May 10 2021

- Little to no impacts...VFR conditions

DISCUSSION: VFR conditions will prevail for the duration of the TAF
period.  Clouds will increase a bit in the mid levels late this
afternoon, but it will not affect flight categories.  Meanwhile,
winds will generally be light and variable.





Short Term...Puma
Long Term...Nield
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