Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Indianapolis in
1250 am EDT Thursday Oct 23 2014
aviation section has been updated below.
issued at 259 PM EDT Wednesday Oct 22 2014
A weak system could bring a few showers to parts of central Indiana
Thursday night. A stronger system will bring better chances for rain
around Tuesday of next week. Otherwise look for dry and near average
to above average temperatures for much of the next 7 days.
Near term /rest of tonight/...
Issued at 936 PM EDT Wednesday Oct 22 2014
current infrared satellite continues to show high pressure over the
region...so no changes to forecast. Updated grids have been sent.
with surface high pressure moving across the area tonight and
ridging building in aloft...expect clear to mostly clear conditions.
Winds will be light with the high in the vicinity.
Given these conditions went with low temperatures near the colder of
the MOS numbers...which puts lows in the middle 30s most locations.
This will allow areas of frost to form overnight. Will go with a
frost advisory all areas.
There is also a potential for some ground fog near sunrise.
Short term /Thursday through Saturday/...
Issued at 259 PM EDT Wednesday Oct 22 2014
Focus is on any chances for rain during the period. Models are close
enough that a blend was used.
Thursday will start off sunny with the ridge overhead...but an upper
trough will quickly approach the area during the day. This will lead
to an increase in middle and high clouds during the afternoon. Not sure
how thick these will be and how they will impact the partial solar
eclipse near sunset.
The upper trough will move across the area Thursday night. There is
some weak isentropic lift with this system...but moisture is limited
with this system...especially in the lower levels. Thus feel chances
for measurable rain are pretty low.
Went slight chance probability of precipitation across roughly the northern half of the area
Thursday night...with sprinkles mentioned farther south. Went dry
far south with that area being pretty far from most forcing.
Area will remain in northwest upper flow Friday into Saturday.
Friday should be dry as central Indiana remains in between
systems...but a front will move into the area on Friday night into
Saturday. Once again moisture is pretty limited.
While cannot rule out some sprinkles Friday night into early
Saturday...feel that moisture is limited enough to keep the forecast
Looking at temperatures...a blend of MOS looks good for highs on
Thursday with the increasing clouds. On Friday mav MOS just looks
too warm given some cloud cover. Went closer to met MOS. Otherwise
generally stuck with a model blend.
Long term /Saturday night through Wednesday/...
Issued at 259 PM EDT Wednesday Oct 22 2014
Pleasant Fall weather continues into early week as surface high
pressure remains the dominant weather feature across the Ohio
Valley. Expect dry pleasant days and cool nights through Monday. As
the high shifts east...surface flow will veer around to southerly
and draw moisture north into the region by Tuesday ahead of low
pressure and an associated cold front lifting out of the Central
Plains. The front will move through central Indiana Tuesday and
Tuesday night...bringing the only chance for rainfall in the
extended period. Model soundings indicate some elevated instability
developing ahead of the front so do expect some embedded thunder.
Highs will be in the 60s through Tuesday...with 70s in southern
Indiana possible on Monday in warm advection regime ahead of the
front. High pressure reestablishes behind the boundary for midweek
but with predominant zonal flow aloft...only expecting temperatures to fall
back into the upper 50s Wednesday.
Some growing hints beyond the extended period of a more unsettled
pattern establishing with the potential for a colder blast of air
into the region for the end of next week. Will continue to monitor
in the days to come.
Aviation /discussion for the 23/0600z taf issuance/...
issued at 1250 am EDT Thursday Oct 23 2014
Visibility restrictions possible with shallow ground fog towards
Strong high pressure ridge will move southeast across our region
bringing clear skies and light winds. There is a good potential of
ground fog at the outlying taf sites from 09z-13z which may
temporarily lower visibilities to IFR category at outlying taf sites
and MVFR at kind where city effect may lessen fog potential a little
On Thursday expect increasing high clouds and southwest winds up to
5 knots. Models indicate an upper disturbance late Thursday night
may spread middle clouds into our region towards the end of the
frost advisory from 4 am to 9 am EDT Thursday for inz021-028>031-
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