Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Indianapolis in
1247 am EDT Tuesday Aug 4 2015
the aviation section has been updated below
issued at 626 PM EDT Monday Aug 3 2015
High pressure will bring dry weather to central Indiana through
Tuesday. Thunderstorm chances will return after that and continue
through Friday night as a pair of upper waves move through the
Ohio Valley and lower Great Lakes. Temperatures will be below
Near term /tonight/...
Issued at 626 PM EDT Monday Aug 3 2015
Pulled probability of precipitation as it appears the last of the storms exited the area
late this afternoon. Look for mostly clear to partly cloudy skies
tonight as drier air moves in behind the departing cold front. MOS
blend temperatures look reasonable with overnight lows in the
upper 50s north to the middle 60s south.
Short term /Tuesday through Thursday/...
Issued at 306 PM EDT Monday Aug 3 2015
On Tuesday the front will meander to the south just far enough to go
slight chance probability of precipitation in the far southwest by later Tuesday
evening...keeping the bulk of the area dry through early during the
By late Tuesday night and into Wednesday the forcing will gradually
increase from southwest to northeast as an upper trough moves toward
the area. This trough will interact with the surface front to
generate increasing chances of rain...with the best shot of rain
this period during the Wednesday night through early Thursday time
period. Went with categorical probability of precipitation for all locations at one point
during this 24 hour time frame. Very high precipitable water in
excess of 2 to 2.5 inches could allow for a couple of inches of
rain. For now have up to an inch in the forecast but rainfall totals
will likely change as we get closer to the event.
Generally stuck with a MOS blend for temperatures...however did
make some minor adjustments on Wednesday night into Thursday to account for
the abundant cloud cover and precipitation expected.
Long term /Thursday night through Monday/...
Issued at 232 PM EDT Monday Aug 3 2015
Regional initialization looks good and follows the models well.
The period will begin with the low pressure system exiting the area
to the east. This will be followed by an upper level wave that will
continue shower and thunderstorm chances through Saturday morning.
Dry weather will then move in as the large upper level high pressure
over the Desert Southwest pushes eastward over Texas and
expands...causing ridging to effect central Indiana. Shower and
thunderstorm chances will return for Monday as another wave
approaches from the plains.
Temperatures will remain below normal to start the period...but will
rebound back to seasonal normals by Sunday night as we move out of
the northwesterly flow pattern.
Aviation /discussion for the 04/0600z taf issuance/...
Issued at 1244 am EDT Tuesday Aug 4 2015
VFR expected at klaf and kind. Some potential for MVFR fog for a few
hours at khuf and kbmg with dew point depressions of only a few
degrees there and some subsidence from the building high.
Scattered VFR diurnal cumulus will be possible this afternoon with winds
9 kts or less out of the west to northwest. Winds will again drop to
calm after sunset.