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Area forecast discussion 
National Weather Service northern Indiana
102 PM EDT Thursday Sep 18 2014

issued at 356 am EDT Thursday Sep 18 2014

High pressure will remain entrenched across the Ohio Valley
through Friday with dry conditions and moderating temperatures.
Highs this afternoon will peak out in the upper 60s to lower 70s.


Short term...(today and tonight)
issued at 356 am EDT Thursday Sep 18 2014

Renewed surface ridging building southeastward out of Canada in behind vigorous SW
trough amplifying eastward across southeast Canada will result in a contn of
stellar lt Summer conds this period. High this afternoon shld again notch a
degree or two warmer than yesterday followed by seasonably cool temperatures
overnight as surface ridge axis passes through County Warning Area.


Long term...(friday through wednesday)
issued at 356 am EDT Thursday Sep 18 2014

An upper level trough will top the upstream ridge and race southeast
toward the western Great Lakes region this weekend. Model solution
spreads among the GFS...Canadian...ECMWF still exist...with the
European model (ecmwf) faster than the GFS with the timing of the initial stronger
trough. Prefer the European model (ecmwf) overall handling of this system including the
timing and convective development Saturday night associated with
this system. Ahead of the cold front...850 mb temperatures still poised to
rise to around 17c...supporting highs near 80 degrees Saturday.
Concern that with relatively warm middle level temperatures...weak initial low
level forcing and somewhat of a low level cap associated with an
elevated mix layer these conditions will keep much of Saturday dry.
Lowered shower/storm chances over northern areas for this reason.
Also some concern that subtropical moisture and remnants of Odile
will reach the area this weekend...however...the latest wpc
forecasts along with model data keep this upper level moisture
generally south of the area. Nevertheless...southern moisture tap
should be sufficient for precipitable water values to rise to around
1.5 inches. The initial cold front should move across the area late
Saturday night/early Sunday morning. A secondary surge of cool air
should reach the area Sunday night. For now...have kept Sunday night
and Monday dry...but there is an outside chance there could be some
showers associated with a secondary upper level trough and cold
front...especially downwind of Lake Michigan where Delta T values
should rise to near 16c given a Warm Lake water temperature of around 20c
per GOES sounder. The surface high pressure area will build into the
area into Monday night...bringing an end to any showers as winds
veer northeast and subsidence increases. The surface ridge of high
pressure will remain over the area with an east wind Tuesday and
Wednesday accompanied by pleasant midweek weather.


Aviation...(for the 18z tafs through 18z Friday afternoon)
issued at 102 PM EDT Thursday Sep 18 2014

Surface ridging in subsident/dry northwest flow should result in a
continuation of VFR conditions/mainly clear skies through the taf
cycle. Could see some patchy fog/stratus development toward 9-12z
Friday...but coverage/confidence remains too low for inclusion
this issuance.


Iwx watches/warnings/advisories...


Synopsis...mesoscale discussion
short term...T
long term...skipper

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