Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 280821

Area Forecast Discussion
National Weather Service Indianapolis IN
421 AM EDT Fri Oct 28 2016

The AVIATION section has been updated below.


Issued at 331 AM EDT Fri Oct 28 2016

Dry and warmer weather is expected through Saturday as the Ohio
Valley remains under the influence of high pressure. A cold front
will drift into the region on Sunday bringing clouds and scattered
showers before stalling then lifting back north on Monday. Warm and
dry conditions will resume for the first half of next week with
cooler weather to follow late week as a cold front brings rain
showers to the region.


.NEAR TERM /Today/...
Issued at 331 AM EDT Fri Oct 28 2016

Low stratus lingers in pockets generally focused over the northeast
half of the forecast area with mid level clouds above early this
morning. Where skies had cleared patchy fog had developed as
well...especially over the Wabash Valley. 07Z temps ranged from the
upper 30s to mid 40s.

A dry and warmer day coming for central Indiana as high pressure
centered over the region this morning moves away to the east with
back side southerly flow developing. Primary focus early this
morning is the gradual diminishing of the lower stratus. RAP 925mb
RH progs and sounding data indicating the inversion may take until
mid morning to completely erode over far northeast portions of the
forecast area. Likewise patchy fog will likely take until 13 or 14Z
to completely diminish.

Once all of the stratus and fog has dissipated...expect a really
nice autumn day with plenty of sunshine and just some passing high
clouds. The arrival of a low level jet into the western Great Lakes
by late day combined with a tightening surface pressure gradient
across the Midwest will support increasing southerly flow by late
day. Most gusts however should hold off until tonight as the low
level jet passes by to the north.

Temps...warm advection will commence with the southerly flow
developing later today. Trended at or just above warmer MAVMOS
guidance for highs in the mid and upper 60s.


.SHORT TERM /Tonight through Sunday Night/...
Issued at 331 AM EDT Fri Oct 28 2016

Forecast challenges focus on precip chances Sunday and temps
throughout the forecast period. Wavy upper flow highlighted by
ridging aloft will promote warm and dry weather through much of the
short term. The passage of a weak wave aloft and an associated cold
front moving into the region on Sunday will provide a brief period
of cooler and potentially unsettled weather before ridging aloft
reestablishes for early next week.

The aforementioned cold front will sag into the lower Great Lakes on
Saturday but will be unable to move any further south into central
Indiana...blocked by ridging aloft and at the surface focused over
the Ohio and Tennessee Valleys. With the core of the low level jet
over the Great Lakes and tight gradient between the cold front to
the north and the surface ridge to the south...expect warm and
breezy southwest winds Saturday.

The approach of the upper wave into the region from the west late
Saturday night and early Sunday will buckle heights aloft and enable
the frontal boundary to make a more concerted push south into
northern portions of the forecast area. The combination of forcing
aloft and weak isentropic lift will likely be enough to generate
scattered light showers in the vicinity of the frontal boundary on
Sunday...focused primarily over areas near and north of I-70 before
transitioning into eastern Indiana by the afternoon as the wave
aloft moves east. Anticipate a fairly cloudy day for most of the
area except perhaps the far south as model soundings favor moisture
becoming trapped beneath a sharp inversion.

The boundary will become quasi-stationary over the forecast area by
Sunday evening before lifting back north towards daybreak Monday in
response to strong low pressure tracking into the Dakotas. Despite
the front remaining in the area Sunday night...lack of appreciable
forcing aloft with the return of upper ridging will limit any
rainfall. The inversion however will only gradually weaken with
cloud cover slow to diminish as well through the night.

Temps...low level thermals support a general model blend for highs
both Saturday and Sunday. Expect upper 70s to potentially lower 80s
for Saturday from north to south. The clouds and the front will keep
temps cooler on Sunday for much of the area...ranging from the mid
60s north to mid 70s far south. Lows will remain primarily in the
50s through the period.


.LONG TERM /Monday Through Thursday/...
Issued at 224 AM EDT Fri Oct 28 2016

Models are close enough that the SuperBlend initialization was
accepted for most items.

Upper ridging will keep central Indiana warm and most of the area
dry until mid week, when an upper trough pushes into the area from
the northwest. Models still differ a bit on timing, but the
uncertainty that far out leads to sticking with the model blend.

Temperatures will remain well above normal into mid week, then cool
some (but still above average) for Thursday.


.AVIATION /Discussion for 280900z TAF Update/...
Issued at 421 AM EDT Fri Oct 28 2016

Lower clouds have moved out of the KIND area, and it appears that a
light southeast wind (some impact from urban heat island) is
preventing fog formation at that site. Thus went optimistic and kept
conditions VFR there.

Previous discussion follows...

Patches of MVFR ceilings continues to hang around KIND/KLAF, so
included a mention of these for the first couple of hours.
Will also see some MVFR fog develop at the sites that could last
through daybreak. Not high confidence in how low it will get or how
long it will last though with high clouds streaming in to the area.

Winds will be light to calm for the rest of the night but then
increase to 5-8 kts out of the southwest by late morning. Could see
some LLWS Friday night.





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