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Area forecast discussion 
National Weather Service northern Indiana
745 PM EST Monday Nov 30 2015

issued at 727 PM EST Monday Nov 30 2015

Chances of rain showers will increase tonight into early Tuesday
morning as an upper level disturbance and cold front approach the
region. Scattered rain showers may persist early Tuesday morning
but dry conditions are expected for most locations Tuesday
afternoon. Another disturbance will bring a likelihood of rain and
show showers on Wednesday. Low temperatures tonight will range
from the upper 30s to lower 40s. High temperatures on Tuesday will
range from the middle 40s across southwest lower Michigan to the
lower 50s across portions of Northwest Ohio.


issued at 727 PM EST Monday Nov 30 2015

Weak echoes this evening extending from southwest lower Michigan
to near kfwa appear to mark the leading edge of a low/middle level
theate advective surge. Any precipitation associated with these weak
echoes will likely be minimal with low level saturation issues to
overcome initially. General idea of previous forecast still
appears to be on track with slow eastward migration of higher
chances probability of precipitation late evening/overnight...with probability of precipitation ramping up more
significantly in the 09z-14z time period as large scale upper
support begins to increase. Evening update to be sent shortly to
remove late afternoon/early evening...but otherwise no significant
changes of note anticipated at this time.


Short term...(this evening through tuesday)
issued at 258 PM EST Monday Nov 30 2015

Continued dry easterly flow has kept our area dry today and will
delay the onset of precipitation this evening. Better push of moisture will
arrive after 00z as 850mb flow veers and advects 6 g/kg mixing
ratios into the County Warning Area. Scattered showers will move into the area with
this push...but with the better forcing to the northwest and the best
moisture southeast of our area...expect total precipitation to be less than
0.10" for most of the area. This is supported by the 16/17z rap/hrrr
which bring very little rain through the area overnight.

Surface dewpoints in the low 40s are currently located southeast of
the County Warning Area and will overspread the area into the evening. This added
low level moisture will bring with it areas of fog developing after
06z. Surface winds look to stay in the 5 to 6 knot range which will
keep the fog from becoming too dense. Although...if winds go calm
tonight...widespread dense fog is a concern. Increased probability of precipitation for the
first part of Tuesday to better reflect the slower progression of
this system. Expect most of the precipitation to be through the area
by middle-day tomorrow as the dry slot overspreads the County Warning Area.


Long term...(tuesday night through monday)
issued at 258 PM EST Monday Nov 30 2015

Precipitation chances will return on Wednesday as primary upper trough axis
and attendant/secondary surface trough swings east through the region.
Decent tropopause pressure advection with vorticity lobe wrap through...and
prognosticated ample deep layer moisture/cyclonic flow...warranted an
increase in probability of precipitation into northwest in/SW lower Michigan late Tuesday night into
Wednesday morning...and points east-southeast into the late morning/afternoon.
Higher probability of precipitation/coverage still anticipated in the north-northwest where some lake
enhancement is expected. Precipitation amounts will be light and more
showery in nature...with ptype mainly snow northwest to a mix of
rain/snow along/east of Interstate 69 given more marginal near surface
temperatures. Could see some light snow accums (<0.5") on mainly grassy
sfcs in Northwest Indiana/SW lower Michigan. Ridging aloft then builds
in thereafter will fair weather and gradual warming.


Aviation...(for the 00z tafs through 00z Tuesday evening)
issued at 727 PM EST Monday Nov 30 2015

Deteriorating aviation weather conditions are expected for this
forecast valid period. Low level moisture advection will continue
to work across northern Indiana the remainder of this evening.
Some light showers or sprinkles are possible with this initial
advective surge...but precipitation should be limited by initially dry
low levels. Better chance of rain should hold off until late
tonight/early Tuesday morning as large scale upper level support
begins to increase with approach of Central Plains upper trough.
Middle level dry slot to rapidly advect across the region Tuesday
morning bringing an end to most measurable precipitation...although a
period of some patchy drizzle is possible before precipitation ends
Tuesday afternoon. Trend to IFR still appears reasonable...with
alternate minimum criteria remaining a possibility late
tonight/early Tuesday. Conditions should improve to VFR or at
least above fuel alternate conditions early Tuesday afternoon as
drier low level air advects into the region.


Iwx watches/warnings/advisories...
Lm...Small Craft Advisory from 9 am to 7 PM EST Tuesday for lmz043-



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

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