Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service northern Indiana
353 PM EST Wednesday Mar 4 2015

issued at 355 PM EST Wednesday Mar 4 2015

Significant weather is expected tonight into Thursday near and south
of the Ohio River as heavy snow is expected with over 6 inches of
accumulation possible. Travel may be difficult in this region.
Elsewhere around the region it will be mostly cloudy and cold. Low
temperatures tonight will drop to below zero across Michigan and
into the single digits above zero central and south. Temperatures on
Thursday will be very cold for early March. Highs will be in the
middle to upper teens.


Short term...(this evening through thursday)
issued at 351 PM EST Wednesday Mar 4 2015

Robust deep latitudinal positive tilted longwave trough supporting
extreme baroclinicity from northestern Texas to Tennessee Valley. Trough to remain
positive tilted and progressive with potent upstream kickers
first across northern Alberta and additional shortwave topping ridge
axis into far northwestern British Columbia. Suppression of southern stream to maintain
primary sensible weather effects well to south of region.
Otherwise...anticipate nominal lake response as lake/800 mb
differentials reach to near 20c by 06 UTC amid 320-325 degree
fetch. Low eql should preclude all but scattered flurries/non
measurable overnight. Slight pop/msrbl mention on Thursday with
slightly hir differentials and Peak Lake induced convective available potential energy to 350 j/kg.
Cloud coverage...especially middle level stream persisting especially
southern/southeastern County Warning Area per WV imagery...affords difficult min temperature forecast
with bust potnl skewed strongly to warm side should breaks fail to
develop. Bottom trough/inflection of Arctic airmass expected Thursday/Thursday
night coincident with low level thermal trough axis across County Warning Area.


Long term...(thursday night through wednesday)
issued at 351 PM EST Wednesday Mar 4 2015

Modification of airmass begins on Friday as upper level pattern
flattens across northern North America. Eastern NAM trough continues
to shift east as the upper level pattern becomes less amplified
over the lower 48. Cold air will be pushed deeper into western NAM
with reamplification of the trough along the dateline.

This sets the stage for a pronounced warmup beginning during the
latter part of the coming weekend into early next week.
Temperatures will be somewhat cooler than the snow

Increased sun angle and less snow cover will allow temperatures
to really being to climb Monday night through the end of the
forecast period. rain and graual melting will keep flooding to a
minimum. Likely to see some ice flow/jam formation by late
weekend into early next week.


Aviation...(for the 18z tafs through 18z Thursday afternoon)
issued at 1242 PM EST Wednesday Mar 4 2015

High end MVFR to low end VFR met ceilings antcipated through the
forecast period as continued low level cold air advection continues. Northern
fringe of lesser/secondary middle level deformation axis could bring
afternoon/evening flurries...though of no visibility impact. Better chance for
nominal lake effect response in vicinity of ksbn late tonight into
Thu,..though again little if any impact to visibility anticipate.


Iwx watches/warnings/advisories...


short term...Murphy
long term...Lewis

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

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

National Weather Service Glossary of Abbreviations