Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus63 kiwx 201034 

Area forecast discussion
National Weather Service northern Indiana
634 am EDT Fri Oct 20 2017

issued at 320 am EDT Fri Oct 20 2017

Unseasonably warm and dry conditions will continue today into
Saturday with highs each day well into the 70s. A cold front will
move through later Sunday into Monday with chances for rain. Much
cooler weather then arrives behind this front into Tuesday and


Short term...(today through saturday)
issued at 320 am EDT Fri Oct 20 2017

Upper ridge axis builds over the region today while surface high
pressure shifts off to the east-southeast. This will result in
unseasonable warmth as low level flow becomes more southerly.
Skies will remain mainly clear under subsident/stable regime

Mild/similar conditions will persist into tonight and Saturday as
south-southwest flow deepens in advance of a deep upper trough.
Some increase in high cirrus is expected, though this should not
impact temperatures as highs once again reach well into the 70s.


Long term...(saturday night through thursday)
issued at 320 am EDT Fri Oct 20 2017

The aforementioned upper trough will fracture eastward with
southern energy into the lower Michigan Valley and northern stream jet
energy more focused through the western/northern lakes. This will
force a slowing/weakening frontal circulation east through the
area later Sunday into early Monday. Good moisture return within
low level jet core and decent right entrance jet dynamics/height falls
should allow for a period of rain along the front. However, expect
line to narrow and diminish a bit in intensity as it shifts east
into the local area during this time. Temperatures will once again
be well above normal into Saturday night/Sunday otherwise.

Strong Pacific jet energy does eventually carve rather substantial
negative height anomalies into the Great Lakes and Ohio Valley by
Tuesday and Wednesday. A brief intrusion of much cooler air will
be the result as strong cold air advection Wing wraps in with lake
enhanced/effect showers under deep trough. Models continue to
suggest at least a partial phase with leftover lower MS valley
shortwave in the transition later Monday-early Tuesday. The GFS
continues to be weaker/farther east (drier) while the European model (ecmwf)
remains more phased/less progressive with a much wetter solution
locally (1-2 inches of rain). Will cover these periods with chance
pops at this range given the differences.


Aviation...(for the 12z tafs through 12z Saturday morning)
issued at 631 am EDT Fri Oct 20 2017

Light winds and clear skies will prevail through the period.


Iwx watches/warnings/advisories...


short term...steinwedel
long term...steinwedel

Visit US at www.Weather.Gov/iwx

National Weather Service Glossary of Abbreviations