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Area forecast discussion 
National Weather Service northern Indiana
347 am EDT sun Oct 4 2015

issued at 347 am EDT sun Oct 4 2015

Light showers and drizzle will persist through the morning hours as
a weak front lifts through the area. Dry conditions expected by
afternoon. Partial clearing will allow highs near 70 degrees over
central Indiana and Ohio while locations near Lake Michigan remain
mostly cloudy with highs around 60. Overnight lows will drop into
the low 50s.


Short term...(today and tonight)
issued at 347 am EDT sun Oct 4 2015

Slowly improving conditions expected today as inverted surface
trough transitions northwest and Atlantic moisture plume is cut off.
Midlevel deformation band will set up shop just to our north/northwest by later
today and should allow most of our County Warning Area to dry out as low level flow
backs and highest Theta-E is shunted out of our area. Will have to
contend with some lingering showers/drizzle in our northwest half
through the late morning though with some residual weak isentropic
upglide and moisture transport up until midday. Pushed back end time
of precipitation a bit based on latest hi-res guidance but overall flavor
of previous forecast largely in tact. Thereafter should start to see
some limited effects of filtered insolation and weak dry air
advection as ceiling heights rise and low clouds begin to scatter in
our southeast. Nothing to really support an aggressive push of drier
air so this process will likely take some time and our northwest may
remain cloudy through most of the day. This leads to a precarious
maximum temperature forecast as areas that break out and tap into warm nose
aloft could easily jump into the low 70s while locations that remain
locked under moisture laden inversion struggle to reach 60f. Kept
upper 60s in the southeast but did trim a degree or two off the northwest
counties given lower confidence clouds will scatter in time. Some
bust potential in either direction. Winds drop off overnight but
should still be a fair amount of cloud cover. This will keep
overnight lows in the low 50s. Some concern for fog development
early Monday morning based on latest NAM forecast soundings and met
guidance. Confidence in these moisture profiles is very low however
and will hold off on mentioning in the forecast for now. Will let
day shift assess with the benefit of more clarity on cloud and near
surface moisture trends.


Long term...(monday through saturday)
issued at 347 am EDT sun Oct 4 2015

Most of the long term period will be characterized by
mild conditions...although the main theme for the for the Thursday-
next weekend period will be toward a more progressive pattern with a
frontal passage followed by cooler conditions Friday/Saturday.

Some residual middle level clouds in vicinity of old weakening
deformation zone may still be persisting across lower Michigan/far
northern Indiana on Monday. These middle clouds should tend to drop
southeastward during the Monday as remnants of old deformation zone
finally get kicked eastward by next northern stream trough working
out of the northern plains. This northern stream wave will remain
well north of local area...and overall low level thermal advections
will remain weak for Monday-Tuesday...with mild air mass remaining
in place. Some question as to cloud cover/middle cloud thickness by
Monday afternoon but it appears highs reaching to around 70 or the
lower 70s are still reasonable. Southward shifting western Great
Lakes anticyclone should allow for onshore flow across Lakeshore
areas...where highs will likely be limited to the middle/upper 60s.

The next feature of interest for Thursday and Friday will be a more
progressive northern stream wave...with models now starting to
exhibit some respectable run to run continuity. A pronounced eastern
Pacific jet should allow for this system to be in a deepening Mode
as it works across the Great Lakes region Thursday night into
Friday...which should be accompanied by a brief period of fairly
robust low level thetae advection ahead of the front. GFS does
depict a narrow 1.5 inch precipitable water axis advecting into the local area
Thursday night along with decent frontal forcing. Given all the
above factors have continued to ramp up probability of precipitation for Thursday
night/early Friday to high chance. Did consider likely probability of precipitation Thursday
night...but will hold off at this time with still enough inherent
timing uncertainty at this forecast distance. Mild temperatures into the
70s are still expected Wednesday/Thursday...with Thursday likely
shaping up as the warmest day of the period when greater prefrontal
mixing is expected.

Temperatures should lower to near seasonable norms behind fridays frontal
passage for the first part of the weekend. However...latest 00z
suite of medium range models are generally in agreement that this
cool down will be short-lived as broad western Continental U.S. Ridging dampens
across central Continental U.S. In advance of next northern stream wave...with
moderating temperatures once again toward the end of the period.


Aviation...(for the 06z tafs through 06z Sunday night)
issued at 132 am EDT sun Oct 4 2015

IFR/LIFR conditions will persist through the early morning as
moisture-laden inverted surface trough swings through the area.
Slow improvement expected thereafter as best forcing and moisture
is shunted northwest. Filtered insolation and weak dry air
advection should allow for transition to VFR by later today though
confidence in exact timing is low...especially at ksbn. Pushed
back timing of improvement a bit based on latest forecast
soundings and MOS guidance but upstream observation are highly variable
and earlier improvement still possible.


Iwx watches/warnings/advisories...
Lm...Small Craft Advisory until 5 am EDT early this morning for



short term...agd
long term...marsili

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