Area Forecast Discussion
Issued by NWS Indianapolis, IN

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215
FXUS63 KIND 240558
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
158 AM EDT Fri Mar 24 2017

.UPDATE...
The LONG TERM Section has been updated below.

&&

.SYNOPSIS...
Issued at 214 PM EDT Wed Mar 22 2017

Cool high pressure overhead will move to the east coast Thursday and
re-establish a southerly flow of milder air in our region. A
weather system impacting the west coast today will bring some rain
showers and perhaps a few storms Friday into early Sunday. An
exit of this system late Sunday will be followed by a brief dry
period before a couple of weather systems in the north Pacific
sweep into the Midwest with mild, showery weather, and perhaps a
few thunderstorms, for much of the next work week.

Severe weather does not appear likely for the next week but
more spring-like temperatures at or above normal will be welcome,
with highs Friday onward in the 60s...and a few 70s south...for
most days.

&&

.NEAR TERM /Overnight/...
Issued at 955 PM EDT Wed Mar 22 2017

Strong high pressure centered over the eastern Great Lakes this
evening continues to provide a dry cool easterly flow of air into
the region. 0130Z temperatures were generally in the 30s..although
a few locations had already slipped into the upper 20s.

Little change needed with another quiet night anticipated as the
forecast area remains firmly under the influence of the high
pressure. Winds have diminished with sunset but a subtle pressure
gradient will likely keep lower levels from fully decoupling
overnight with winds staying up at 5-10mph most areas. This
combined with the onset of warm advection should counteract the
very dry flow of air from the east and keep temperatures from
bottoming out overnight. Still will be a chilly night as lows
fall into the 20s all but the lower Wabash Valley. Nudged lows
down a couple degrees in the northeast counties...otherwise no
changes to temperatures overnight.

Will continue with the Freeze Warning for just Jackson and
Jennings Counties overnight where confidence is higher in
achieving 3-4 hours below freezing and potentially at or below 28
degrees. Further west over southern counties from Lawrence Co to
Knox/Sullivan Cos...temps near to just below freezing for a short
period of time during predawn hours and will keep them out of the
headlines. Thankfully...this looks like the last night for a while
where freezing temperatures will be an issue.

Zone and grid updates out.

&&

.SHORT TERM /Thursday through Saturday/...
Issued at 214 PM EDT Wed Mar 22 2017

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

Southeast surface winds begin a return of slightly milder and
more humid air Thursday. Temps should top out a degree or so
cooler than previous forecast as winds remain more southeasterly
out of cool high. Mid cloud will increase Thursday afternoon as
warm advection ensues. A few sprinkles may occur Thursday
afternoon and evening as upper ridge arrives but lower levels
are so dry am not certain rain will be a player. Will keep for now.

Upper ridge passage in advance of todays west coast trough
deepening in the Plains Friday returns drier condition here
late Thursday night through Friday evening. As system continues
its approach, chance showers Friday night become likely for
Saturday. And with elevated instability Saturday...thunder appears
in play then.

Temperature guidance blend appears pretty good and will be
followed with last subfreezing night for awhile occurring tonight.

&&

.LONG TERM /Monday through Thursday/...

Issued at 158 AM EDT Fri Mar 24 2017

ECMWF suggests lingering rain showers will remain in the area on
Monday as another upper level short wave is poised to push through
the Ohio Valley. A surface low will accompany this system on
Monday...pushing across Indiana. Thus have included pops
continuing on Monday.

Dry weather should return on Tuesday and Wednesday as the ECMWF
suggests High pressure building at the surface with Ridging in
place aloft. An Intrusion of cold air seems unlikely as the
ridging builds within the southwest flow aloft. THus will trend
temps at or above seasonal normals.

By Thursday...return flow of warmer and perhaps more humid air
begins as surface high pressure is east of Indiana. Forecast
Builder blend appears to overplay pops here given the uncertainty
and the apparent lack of dynamics. Thus have trended to a dry
forecast on Thursday where possible.

&&

.AVIATION /Discussion for 240600Z TAFS/...
Issued at 1230 AM EDT Thu Mar 23 2017

VFR visibility through the period. VFR decks drop to MVFR around
2000 feet AGL from 241500z-241900z as moist lower layer advects
northward from Kentucky in warm frontal type behavior.

Low level wind shear overnight but as warm frontal layer overtakes
the area Friday, surface winds will become increasingly gusty,
especially when lower decks rise and break for the afternoon hours
Friday.


&&

.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...Tucek
NEAR TERM...Ryan
SHORT TERM...Tucek
LONG TERM....Puma
AVIATION...Ryan



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