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Next 12 Hours

Forecast data from the National Digital Forecast Database.

5 Day Forecast

• Monday
• 
• High: 90 °
• Low: 68 °
• Chance of a Thunderstorm

• Tuesday
• 
• High: 84 °
• Low: 66 °
• Chance of T-Storms

• Wednesday
• 
• High: 77 °
• Low: 59 °
• T-Storms

• Thursday
• 
• High: 70 °
• Low: 50 °
• Chance of Rain

• Friday
• 
• High: 70 °
• Low: 50 °
• Clear

Area forecast discussion 
National Weather Service Indianapolis in 
1050 am EDT Monday may 20 2013 


Update... 
the near term section has been updated below. 


&& 


Synopsis... 
issued at 300 am EDT Monday may 20 2013 


A large upper low currently over the plains is expected to bring 
unsettled weather to the area through Thursday as it slowly moves 
east and weakens with time. High pressure is expected to build in 
behind this system towards the end of the week. Another frontal 
system may approach the area by next Sunday. 


&& 


Near term /rest of today/... 
issued at 1045 am EDT Monday may 20 2013 


Outflow boundary currently moving into the western border zones 
seems to be losing its eastward push...but still quite a dewpoint 
gradient along it with dewpoints falling into the upper 50s behind 
boundary. 


Remnants of this boundary may move farther into the area this 
afternoon as it weakens. Convection may develop along this boundary 
later this afternoon as air mass is expected to become very 
unstable...however a middle level cap noted on this morning/S upper air 
may help suppress convection. Model data weaken this cap by middle to 
late afternoon...but some question as to whether this will actually 
happen. Will keep chance probability of precipitation going for mainly later this afternoon. 
If storms can break the cap...lapse rates quite favorable for 
severe...although deep shear continues to look rather weak. 


Quite a bit of cloud cover has developed over the past couple of 
hours...although satellite indicates some thinning recently. As a 
result...will lower the highs today a couple of degrees. 


Previous discussion follows. 


Models still hinting at a weak boundary originating from convective 
activity to the west that will move into the area this afternoon. As 
so...the air mass will become very unstable later today with lifted 
indexes around -7/-8 and steep low level lapse rates. Will continue to 
carry chance probability of precipitation with the highest amounts to the north. Very warm 
temperatures expected today...and along with the higher dew points 
will make it feel much like a middle Summer/S day. Leaned closer to the 
warmer met for high in the upper 80s to around 90. 


&& 


Short term /tonight through Wednesday night/... 
issued at 300 am EDT Monday may 20 2013 


Models progging better chances for showers and thunderstorms...and 
potentially severe for tonight...as much of the County Warning Area is in a slight 
risk. Bumped up much of the forecast area to likely based on good 
model consensus. 


The rest of the period looks very unsettled with rounds of 
convection making the position of the cold front hard to find. 
However it appears models have bumped up the timing of the main cold 
front to Wednesday...rather than Wednesday night. Have likely probability of precipitation in for 
Wednesday...but before and after that cannot really pin down any periods 
to concentrate high probability of precipitation on...so will continue to broadbrush high 
chance probability of precipitation Tuesday through Tuesday night and again Wednesday night. 


&& 


Long term /Thursday through Monday/... 
issued at 233 am EDT Monday may 20 2013 


End of an active weather period is anticipated in the long term portion 
of the forecast...as low pressure pulls out of the area and a 
broad surface ridge settles into the region downstream of an upper 
ridge across the central portion of the country. Not overly 
pleased with allblend initialization probability of precipitation beyond Thursday as it 
wants to introduce another lengthy period of slight chance to 
chance probability of precipitation over the weekend and into next week...even with this 
surface ridge across the area and limited if any upper level 
support for precipitation. Have gone dry from Thursday night on. 


On temperatures...expecting numbers closer to seasonable levels...if not 
slightly below at times throughout the period. If dry forecast 
holds...could make for a very pleasant Holiday weekend across 
central Indiana. 


&& 


Aviation /discussion for the 201500z ind taf update/... 


Brief MVFR ceilings are expected the next 1-2 hours. Observational trends and 
satellite show broken cumulus across several of the taf sites. As heating 
continues cloud condensation level/S are expected to rise above 3000ft and VFR ceilings 
will be the rule this afternoon. 


Plenty of cape and instability still appear available this 
afternoon based upon forecast soundings. Thus for now the ongoing 
thunderstorms in the vicinity seems reasonable. 


Previous discussion below 


/discussion for the 20/12z tafs/... 
issued at 713 am EDT sun may 19 2013 


MVFR conditions at some sites early in the period in fog and stratus 
will give way to VFR conditions later today...outside of any 
potential showers and thunderstorms. 


Warm moist airmass in place across the area...primed for possible 
showers and storms later today and tonight. Uncertainties in timing 
and coverage preclude explicit mentions beyond thunderstorms in the vicinity/cumulonimbus from midday 
on. 


Winds will generally be out of the south and will become gusty 
today...into the low to middle 20kt range. Gusts will subside this 
evening but winds will remain near 8-10kt. 




&& 


Ind watches/warnings/advisories... 
none. 
&& 


$$ 


Synopsis...smf 
near term...smf/jas 
short term...smf 
long term....nield 
aviation...nield/jp 


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