Area Forecast Discussion
Issued by NWS Indianapolis, IN
FXUS63 KIND 261732
Area Forecast Discussion
National Weather Service Indianapolis IN
132 PM EDT Wed Apr 26 2017
The AVIATION Section has been updated below.
.SYNOPSIS...Low pressure over eastern Iowa with a cold front
extending across the middle Mississippi valley to Texas will move
east across Indiana later tonight and early Thursday bringing
numerous showers and scattered thunderstorms.
Brief drying will occur late Thursday and Thursday night as weak
ridge of high pressure briefly builds in.
Very wet weather will occur over the weekend as a warm front
develops over the Ohio valley Friday and moves slowly north as
low pressure over the southern plains moves towards the great lakes
by Sunday night. A trailing cold front will push east across
Indiana Sunday night
Quieter weather will occur after the weekend...but another system
will move our way by the middle of next week.
.NEAR TERM /This afternoon/...
Issued at 1237 PM EDT Wed Apr 26 2017
Have increased sunshine for the afternoon and have bumped max
temperatures upward in western counties based on sunnier forecast.
Still projecting lead edge of showers and storms to reach state
line 5 to 6 pm and a brief period near Indy around 8pm. Await main
precipitation thrust to come in late tonight.
.SHORT TERM /Thursday through Friday Night/...
Issued at 355 AM EDT Wed Apr 26 2017
A cold front extending south from a surface low over the northern
great lakes across Indiana around 12Z Thursday will move rapidly
to the east. Thursday will start out breezy and wet with showers
and a few thunderstorms. All of this will end Thursday afternoon
as cold front moves quickly east and weak ridge of high pressure
temporarily builds in Thursday night.
Models develop a warm front over the Ohio valley Friday and move it
north Friday and Friday night as low pressure deepens over the
southern plains. We can expect a chance of showers by Friday
afternoon and numerous showers and a few thunderstorms developing
Friday night as we move towards a very wet weekend.
In most cases stayed close to a MOS blend on temperatures and overall
Superblend temperatures generally accepted with only a few minor
.LONG TERM /Saturday through Wednesday/...
Issued at 253 AM EDT Wed Apr 26 2017
Models continue to suggest a very active long term period. Warm
frontal zone is likely to set up somewhere in the region, likely
south, early in the weekend with widespread precipitation and likely
thunderstorms along and north of the boundary. A low pressure system
will organize and move into the Great Lakes, pushing the warm front
north and allowing the area into the warm sector, before the cold
front swings through the area Sunday night. Thus, expect a wet
weekend with multiple rounds of showers and thunderstorms.
Precipitation potential with the upper low and wraparound will
necessitate some low chances for showers into Monday.
These multiple rounds of showers and storms could pose a hydrologic
threat and will merit monitoring as the week wears on, especially
with the potential for prior precipitation during the short term
period. Even accounting for the GFS tendency to overdo moisture,
precipitable water values over the region this weekend will likely
approach and perhaps even briefly exceed the 99th percentile value
for the time of year climatologically speaking. River interests and
those in flood prone areas should remain alert to the forecast as
the week wears on.
.AVIATION /Discussion for 261700z TAFs/...
Issued at 124 PM EDT Wed Apr 26 2017
Synopsis...strong low pressure trough and cold front from
Wisconsin to Oklahoma today will sweep into Indiana after
midnight tonight and across the state early daybreak hours
VFR to prevail through 271000z then behind cold front IFR decks
around 1000 feet through 271800z.
Isolated thunderstorms will develop 262200z-2400z and be a threat
for 2-3 hours. Afterwards, steadier showers and isolated
thunderstorms arrive ahead of cold front after 270600z, departing
Winds from the south will be strong and gusty through early
evening today. As winds settle down after dark wind shear to
become an issue with winds aloft to 45 knots.