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Area forecast discussion 
National Weather Service Indianapolis in
255 PM EDT Sat Jul 4 2015

long term section has been updated below.


issued at 207 PM EDT Sat Jul 4 2015

Dry weather is in store this Fourth of July weekend as high pressure
camps out over the area. Showers and thunderstorms will be back in
the picture by Monday night as a cold front approaches from the
northwest and stalls nearby.

Temperatures will briefly return to normal with afternoon highs in
the lower to middle 80s on Sunday. will cool off a bit
again by Tuesday with highs in the middle 70s to around 80 through


Near term /tonight/...
issued at 207 PM EDT Sat Jul 4 2015

Quiet Fourth of July night in store for central Indiana weather-wise
under high pressure...with the only fireworks expected...being the
store bought kind. This should make those planning outdoor
activities satisfied if not Happy. Main focus will be on
temperatures as any diurnal cumulus will be lost at sunset and similar
model relative humidity time sections and satellite trends only hint at some
passing cirrus in west flow aloft.

850 temperatures from 13 to 14 degrees celsius...light to calm
winds...mostly clear skies and upper 50s to lower 60s dew points
suggest overnight lows will be at or slightly below 12z MOS numbers
in the lower to middle 60s. Could also see more overnight patchy fog.


Short term /Sunday through Tuesday/...
issued at 207 PM EDT Sat Jul 4 2015

The main focus for the short term will be on arrival timing and
coverage of thunderstorms early next week as models agree a cold
front will be approaching central Indiana from the northwest on

Although the models toy around with spotty quantitative precipitation forecast at various times
across our southern counties through Monday...associated with
developing Tennessee Valley upper low...think upper ridging over the
Great Lakes should keep things mostly dry with shower and
thunderstorm chances too low to mention. It will also be warmer with
850 millibar temperatures increasing a few degrees to 15 to 16
degrees celsius on Sunday and 17 to 18 on Monday. 850 millibar
forecasting chart using mostly sunny skies per model relative humidity time
sections and cumulus development forecasts suggests afternoon temperatures at
or near 12z MOS with normal highs in the lower to middle 80s Sunday and
middle to upper 80s Monday.

Things should change by Monday night as a cold front approaches from
the northwest...and an upper trough moves through on Tuesday. The
models...especially the NAM...are trending slower with the
Mississippi Valley part of the front. The NAM is actually faster
with the surface low and northeastern part of the front. With the
12z run...the GFS is now closer to the 00z European model (ecmwf)...00z gefs mean and
ecens mean with the frontal position. This would be from around
South Bend to Oklahoma City at 12z Tuesday...Fort Wayne to St. Louis
at 18z and Muncie to Indianapolis to Terre Haute at 00z Wednesday.
This looks like a reasonable progression based on trends and last
night's ensemble means. This would also favor holding off chance
probability of precipitation until overnight Monday night.

At any rate...the synoptic forcing will interact with increasing
moisture and instability and should result in more widespread storms
on Tuesday...when model time sections show the deepest moisture and
strongest vertical velocities. Likely probability of precipitation continue to look good.

The widespread storms and thick cloud cover will result in cooler
temperatures on Tuesday with highs in the middle 70s to lower 80s per
ensemble MOS looking good.


Long term /Tuesday through Saturday/...
issued at 255 PM EDT Sat Jul 4 2015

The cold front which will push across our region Tuesday will stall
near the Ohio River Wednesday as high pressure builds into the Great
Lakes. Both the GFS and Euro have trended wetter across southern
portions of central Indiana Tuesday night and Wednesday and will add
likely probability of precipitation across our south there with chance probability of precipitation elsewhere. A
weak area of low pressure will move east along the front Thursday
and another weak system will move our way towards Saturday. Went
with chance probability of precipitation most areas Thursday through Saturday...but my
confidence for rain seems low until Saturday.

Highs will be in the upper 70s early on rising to the lower to
middle 80s by Saturday with lows mostly in the 60s rising to the
upper 60s to near 70 by the weekend. Went slightly warmer than
super blend on lows Tuesday night and Wednesday night due to lots of
clouds and some precipitation. Otherwise...only minor changes made


Aviation /discussion for the 041800z taf issuance/...
issued at 1250 PM EDT Sat Jul 4 2015

Mainly VFR with brief MVFR fog possible late tonight at outlying taf

Weak high pressure over northern Illinois will move to eastern Ohio
by midday Sunday...while a weak area of low pressure remains across
Tennessee. Airmass will remain quite dry over north and central
sections with a little more moisture for daytime cumulus south of
Interstate 70.

Expect few cumulus over northern sections while kbmg may see broken cumulus
around 4 thousand feet this afternoon. All of this will clear out
tonight with patchy MVFR fog possible at kbmg...klaf and khuf tafs
from 08z to 12z Sunday. After that VFR with a few cumulus again Sunday.

North to northwest winds around 5 knots this afternoon becoming
light tonight and southeast around 5 knots Sunday.


Ind watches/warnings/advisories...

long term....jh

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