Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 072016

Area Forecast Discussion
National Weather Service Indianapolis IN
316 PM EST Sun Mar 7 2021


The Short Term, Long Term, and Fire Weather sections have been
updated below.


.SHORT TERM /Tonight through Monday Night/...
Issued at 316 PM EST Sun Mar 7 2021

Guidance continues to show dry and warmer weather through the
short term as surface high pressure pushes eastward and upper
level heights build across the region.

Primary potential for impacts during the short term exists in the
realm of fire weather. See the Fire Weather section below for

Winds will increase tomorrow as the surface high pushes eastward
and warm advection and strong insolation promotes a well mixed
boundary layer. BUFKIT momentum progs suggest gusts into the mid
20KT range will be possible.

Min temps through the short term from the blend appear quite
reasonable, and see little reason for deviation. However, max
temps on Monday looked at least 3 degrees or so too cool given
the plentiful sunshine, ample boundary layer mixing, and fairly
dry surface, as well as the tendency in good warm advection
scenarios, particularly as the transition season begins, for
guidance to underperform. Expect the mid 60s to be easily
reachable across the entire area tomorrow.


.LONG TERM /Tuesday through Sunday/...
Issued at 316 PM EST Sun Mar 7 2021

A warm start to the extended period will shift back to cooler and
more seasonable conditions by the weekend as a slow moving cold
front drops through the region and produces multiple opportunities
for moderate to heavy rainfall,

Strong high pressure will center across the southeast part of the
country through midweek will maintain a nice S/SW low level flow
bringing the warmest temperatures of 2021 so far...likely on Tuesday
through Thursday. Suspect model guidance continues to not capture
potential warmth well at all considering the strength of the warm
advection. Have continued the trend of going a few degrees above
guidance for highs through Thursday. Mid 60s look solid and not out
of the question that a few spots make an effort to push 70 degrees.

The return to a more active weather pattern is set for late week as
the upper ridge breaks down and allows a cold front to progress
southeast into the Ohio Valley. The development of a deep upper low
over the four corners region by early Friday in tandem with strong
high pressure over the Gulf of Mexico will promote a broad
southwesterly flow aloft. This upper level pattern combined with a
continued Gulf fetch and the presence of the frontal boundary
becoming quasistationary over the Ohio Valley...will increase the
possibility for an prolonged stretch with periods of heavier
rainfall for late week. Confidence remains too low for a thunder
mention at this point but potential is there...especially late
Thursday into Friday.

Uncertainty increases with respect to the location of the front over
the weekend as global models have shifted that south of the forecast
area Saturday with a strong PV lobe tracking through the Canadian
Maritimes. Possible that showers may diminish for a period from
Saturday afternoon into early Sunday before returning again late
next weekend with the approach of the upper low from the southwest.
High temperatures will fall back into the upper 40s to mid 50s for
Saturday and Sunday.

Still a lot to hash out with the specifics and the potential that
the forecast area will eventually end up on the north side of the
front by late week and the weekend. The main takeaway at this point
is the possibility at a threat for locally heavy rainfall that will
renew flooding over parts of the region.


.AVIATION /Discussion for the 07/18Z TAFs/...
Issued at 1220 PM EST Sun Mar 7 2021

*IMPACTS: VFR through the period with light and variable winds
 gradually becoming stronger and more southerly/southwesterly late
 in the period. Gusts expected tomorrow late morning onward.

*DISCUSSION: High pressure remains the dominant feature over the
 area. Expect little more than a few passing cirrus as a result,
 and winds will be light and variable, gradually becoming more
 southerly. By late in the period...after about 16Z Monday, winds
 will be southwesterly and become stronger and gusty, with wind
 gusts approaching or exceeding 20KT at the end of the period and
 into the 30 hour period at IND. May be able to push 30KT at peak
 gustiness tomorrow afternoon.


Issued at 316 PM EST Sun Mar 7 2021

As mentioned above, plentiful sunshine and a strengthening
pressure gradient will promote a reasonably well mixed boundary
layer on Monday afternoon. Fuel moisture values in the 7 to 8
percent range will be the only criteria met on a widespread basis,
but 20 foot winds will approach or exceed 15 MPH at times in some
areas. While dewpoints will be on the increase, albeit slowly
with the Gulf still closed off to any good return flow, quality
mixing will be working against this rise, and expect that rise to
stall or reverse for a time in the afternoon. Thus, afternoon
minimum relative humidity values will likely drop well into the
low 30s and perhaps even the upper 20s in a few spots. This will
set the stage for an elevated fire danger midday Monday into late
afternoon. True Red Flag conditions are unlikely, however. Will
message this situation to relevant partners in the afternoon fire
weather products.





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