Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 03/08/19

Area Forecast Discussion

National Weather Service Northern Indiana

 940 PM EST Thu Mar 7 2019

.SYNOPSIS...
Issued at 938 PM EST Thu Mar 7 2019

There is a chance of light snow overnight into early Friday
morning, mainly south of Route 24. Elsewhere, clouds will
increase overnight with scattered flurries possible. Dry
conditions are expected Friday afternoon with high temperatures in
the mid to upper 30s. This will be followed by a wet and windy
weekend. Widespread rain is expected Saturday afternoon with winds
possibly gusting up to 40 mph on Sunday. Quiet weather returns on
Monday with temperatures hovering around normal.

&&

.UPDATE...
Issued at 929 PM EST Thu Mar 7 2019

Based on latest observational/guidance trends, have continued
diminishment of PoPs/snow accums for tonight. Initial mid level
wave which brought some light snow to west central Indiana/east
central Illinois is skirting southeast of the area. Better chances
of light snow across the south appear to hold off until later in
the overnight hours as next low amplitude mid level trough kicks
out of the Mid MS Valley. Inspection of regional AMDAR soundings
across northeast Illinois continues to indicate very dry low
levels which should slowly saturate late in overnight hours as
this next upstream wave approaches with an accompanying increase
in isentropic lift toward daybreak. Will limit PoPs
overnight/Friday morning to mid chance across the far south due to
weak nature of forcing and moisture limitations. Have limited any
indication of dusting snow accums to areas south of Route 24.

&&

.SHORT TERM...(This Evening through Friday)
Issued at 327 PM EST Thu Mar 7 2019

Several weak and highly sheared shortwaves will ripple through the
area through tomorrow with little fanfare. What little dynamics and
moisture is available will be focused primarily south of our CWA.
Best chances for our area will be late tonight/early Fri when final
weak shortwave takes a more northern track across our area.
However...QG omega remains incredibly weak with limited moisture
advection and a dry antecedent airmass. Ceiling heights in our SW
currently well above 10 kft with 15 degree surface dewpoint
depression. Moisture quality increases slowly overnight as low level
winds back but full saturation will take time. Current thinking
based on latest 12Z guidance (including hi-res) is that best precip
chances will not arrive until 09Z and even then we may struggle to
get anything more than flurries. Have therefore made some
significant cuts to PoPs and QPF/Snow. Some concern for patchy
freezing drizzle early Fri morning. Forecast soundings currently
indicate saturation deep enough to support nucleation (when
saturated enough to precipitate) but not by a large margin and some
concern conditions may end up slightly drier than currently
predicted. Left just a brief mention of freezing drizzle in the far
south and will let later shifts monitor.

&&

.LONG TERM...(Friday Night through Thursday)
Issued at 327 PM EST Thu Mar 7 2019

Attention then turns to rain and wind event over the weekend.
Another deep and negatively tilted trough will lift into the Great
Lakes. Coupled upper jets and highly curved mid/upper level flow
will support strong ascent and strong SSW flow will advect very
moist airmass into the area. Not expecting any mix (even at the very
onset) with late day timing and strong WAA surge. Moisture quality
and degree of forcing support solid 0.5 to 0.75 inches. Can`t rule
out an isolated thunderstorm but current forecast soundings show
very paltry lapse rates and virtually no elevated instability. Winds
will be a concern...primarily during and after the dry slot pushes
through Saturday night. Strongest gradient and best isentropic
descent arrive overnight when mixing potential is lowest. Could
flirt with advisory criteria during the day Sunday but gradient
steadily weakens during that time. A few gusts around 45 mph
possible but certainly nothing like our last wind event.

Another quiet stretch heading into Monday with a decent ridge moving
overhead. That will be quickly followed by another deep, southwest
CONUS trough lifting NE with another round of rain midweek. Temps
generally hovering around average for this time of year.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
Issued at 938 PM EST Thu Mar 7 2019

A weak system tracking out of the Mid MS Valley tonight will
spread light snow across central Indiana and portions of north
central/northeast Indiana. Low levels remain quite dry late this
afternoon and weak nature of this system will keep better moisture
advection suppressed to the south of the area. Best chance of
some light snow with this system still appears to be at KFWA in
the 10Z-15Z window Friday, but the possibility exists that
measurable snow will remain limited to south of KFWA. Any light
snow may end as a period of drizzle Friday morning as temperatures
warm above freezing. Some light snow possible at KSBN Friday
morning, but confidence and very light nature to any precip
precludes a mention with the 00Z TAFs. VFR conditions should
prevail outside of a relatively narrow window for some MVFR cigs
above 2k feet at KFWA Friday morning. Winds to remain light this
period from east-southeast backing slightly to east-northeast
toward the end of the forecast period.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

UPDATE...Marsili
SYNOPSIS...AGD
SHORT TERM...AGD
LONG TERM...AGD
AVIATION...Marsili


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