Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service northern Indiana
751 PM EDT sun Aug 30 2015

issued at 739 PM EDT sun Aug 30 2015

A weak trough will continue to sag slowly southeast across the
area tonight and Monday. A few showers and thunderstorms are
possible over central portions of Indiana and Ohio Monday
afternoon... otherwise dry conditions will continue. Lows tonight
will be in the lower to middle 60s with areas of fog likely late.
Highs Monday will be in the middle 80s.


Short term...(this evening through monday)
issued at 355 PM EDT sun Aug 30 2015

Increased instability across eastern County Warning Area with sbcapes to 2000-2500
j/kg as surface T/dew point reach the middle 80s/upper 60s...hiest across far southeastern
County Warning Area. Focus for lift associated with weak trough passing through southeastern
half of County Warning Area this afternoon should aid in continued uptick in
convective development...though anticipate relatively meager
coverage given weak shear environment. Additionally southward moving middle
tropopause vorticy over southeastern Michigan per WV imagery to aid in general ascent
thi aftn/eve. Convection strongly tied to diurnal heat cycle with
marked downtrend in chances shortly after sunset.

Concern for br/fog and stratus development late tonight. Expansive
stratus/visibility reductions Neath upstream surface ridge/northwestern County Warning Area quite slow
in mixing today. Given weak/none surface flow overnight along with high
925mb relative humidity fields...stratus/br to likely expand in coverage again over
southern Great Lakes. 10-15 knots flow at 925mb should serve to
sufficiently mix blyr for stratus Blossom. Only slight chance probability of precipitation far
southern/southeastern County Warning Area associated with surface dps pooled to upper 60s/near 70 along
diffuse surface feature and possible peripheral vorticity /currently
across far western Kentucky/ swept into vorticity channel/into cntl in. Little change
with respect to for a cooler/drainage flow tonight along
Berrien Colorado shoreline/kbeh.


Long term...(tuesday through sunday)
issued at 355 PM EDT sun Aug 30 2015

Its looking to be a toasty week. The 500mb ridge over our area
continues to build through the long term period as a trough moves
into the western Continental U.S.. 850mb temperatures are expected to rise to 17-
20c...which puts temperatures in the upper 80s for inland locations.
Normal temperatures for the first week of September range from the
upper 70s to low 80s.

Uncertainty exists however about the chances for precipitation this
week. The Fly in the ointment is that there are a couple of weak
shortwaves aloft that models generate convection for Tue-Fri. In the
absence of any mentionable forcing associated with these waves...I
am hesitant to include any probability of precipitation at all...except Tuesday/Wednesday
when the strongest of these waves moves through. Have limited these
to slight chance...mainly in the afternoon. If anything does
develop...expect it to be isolated and non-severe. Otherwise...kept
conditions dry Thursday through sun...where slight chance of showers/T-
storms is possible in the west and central.

Added patchy fog to the forecast for late Monday night/Tuesday
morning given light winds and low level moisture.


Aviation...(for the 00z tafs through 00z Monday evening)
issued at 739 PM EDT sun Aug 30 2015

Cumulus over the area will continue to slowly dissipate with loss of
heating this evening. Lingering low level moisture combined with
radiational cooling overnight should lead to fog/stratus with
MVFR/IFR conditions developing late tonight... then burning off by
late morning with predominantly scattered cumulus and VFR conditions likely
for the rest of the day.


Iwx watches/warnings/advisories...


short term...Murphy
long term...Dodson

Visit US at www.Weather.Gov/iwx (all lower case)

Follow US on facebook...twitter...and youtube at:

National Weather Service Glossary of Abbreviations