Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service northern Indiana
428 am EDT Wednesday Aug 20 2014

issued at 156 am EDT Wednesday Aug 20 2014

A weak ridge of high pressure will settle into the Ohio Valley
today. However...a weak upper level disturbance tracking across the
Great Lakes will provide a low chance of an afternoon shower or
thunderstorm on today across far Northeast Indiana...south central
lower Michigan...and Northwest Ohio. High temperatures today will
range from the upper 70s across central lower the
lower to middle 80s across central Indiana.


Short term...(today and tonight)
issued at 427 am EDT Wednesday Aug 20 2014

Better low level mixing along with some lingering clouds early this
morning have helped avert fog development. Drier air will temporarily
spread into the area today before moisture surges back northeast
into the area ahead of the next system tonight. The
GFS/NAM/Gem/ECMWF all support low level Theta-E flux increasing with
sufficient lift for storms tonight. Favored this general model blend
and trended shower/storm chances higher late tonight. Given a more
elevated storm nature tonight and limited convective available potential energy...storms are not
expected to become severe. As for temperatures...both the NAM/met
and GFS/mav support temperatures above normal with highs generally
in the middle 80s.


Long term...(thursday through tuesday)
issued at 427 am EDT Wednesday Aug 20 2014

Warm front expected to move NE into our County Warning Area Thursday in response to
shortwave lifting slowly NE across the northern plains/upper Midwest. This
should result in at least scattered thunderstorms in the area given combination of
decent low level forcing and very moist/moderately unstable airmass.
Northeastward progress of warm front across our County Warning Area may be hindered by
outflows from thunderstorms along the front Thursday-Friday which could also result
in locally heavy rainfall. By Saturday the warm front should wash
out as upper ridge strengthens over the MS valley/western Great Lakes in
response to trough digging into the northern rockies. This should result in
hot/humid conditions in our area over the weekend with isolated
thunderstorms at most. As western trough lifts into the northern plains early
next week a weakening cold front expected to approach our area from the west-northwest
bringing a chance of thunderstorms by Tuesday along with a downward trend in
temperatures... though will still be very warm and muggy at least through


Aviation...(for the 06z tafs through 06z Wednesday night)
issued at 156 am EDT Wednesday Aug 20 2014

The upper level trough was moving into the forecast area...with
showers and storms ahead of this system and east of the taf
sites. Better low level mixing tonight was helping to keep fog
from forming. Kept a tempo MVFR fog group at both sites given
favorable diurnal timing. Low level Theta-E convergence will
increase tonight...with the best chance for storms after the end
of the taf for now...left thunder out of tafs.


Iwx watches/warnings/advisories...


short term...skipper
long term...jt

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

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

National Weather Service Glossary of Abbreviations