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Area forecast discussion 
National Weather Service northern Indiana
107 am EDT Sat Aug 30 2014

Synopsis...
issued at 107 am EDT Sat Aug 30 2014

Today will feature warm and humid conditions as a warm front lifts
north of the area. Skies will be partly cloudy with highs likely
reaching the 80s. Scattered showers and thunderstorms will be
possible by mainly this afternoon and evening as low pressure
tracks into the Great Lakes region. Drier air will briefly work
into the area on Sunday before a cold front brings renewed chances
for showers and thunderstorms on Monday. Highs on Sunday and
Monday are forecast to reach the low to middle 80s.

&&

Short term...(this evening through saturday)
issued at 323 PM EDT Friday Aug 29 2014

Warm front making quick progress northward this afternoon in association/west SW trough and
attendant surface cyclone lifting northeastward out of the plains. Broad belt of
ll moisture flux tied to low level jet within Theta-E ridge leading to an
expanding area of rain showers/embedded thunderstorms and rain across western zones extending southwestward
into eastern Illinois/western in and expect this will continue to gravitate north/northeastward
through this afternoon. Southeastern half though expected to remain dry given
influence of western periphery of retreating Continental ridge and poor
eastward moisture flux bound.

Otrws west/warm front lifting through this evening do not see much of an
appreciable focus Sans far northwest zones for anything more than a
threshold lower bound slight chance pop mention. On Sat warm sector is
fully entrenched across County Warning Area along west/a very moist airmass. Diurnal heating
shld Foster sig instability by afternoon and west/southern edge of height falls in
association/west ejecting plains SW and approaching surface frontal zone will keep
west/prior likely probability of precipitation although did add some temporal detail to Sat
morning. Some low risk for severe (damaging winds) per modest 0-6km
bulk shear near 30-35kts which combined west/precipitable waters near 2 inches suggestive
of local mass loading and a pulse severe threat. Much warmer west/low to
middle 80s west-east across County Warning Area.

&&

Long term...(saturday night through friday)
issued at 323 PM EDT Friday Aug 29 2014

Main focus in long term remains on timing of precipitation chances and
potential for additional heavy rainfall. Upper trough and associated surface
boundary will be moving across the area Saturday night with rain
chances continuing through the overnight hours. As mentioned by several
previous shifts...localized heavy rainfall remains a threat as
impressive Gulf moisture transport continues into the area (pwats in
the 1.7 to 2 inch range which is near 99th percentile for this time
of year). System will exit during the day Sunday with precipitation
tapering off from northwest to southeast. Latest 12z model runs in agreement with
timing and suspect most of Sunday will be dry...especially in northwest so have
cut probability of precipitation further especially during the afternoon/evening hours. Brief dry period
likely into the start of Labor Day as forcing diminishes and
shortwave ridge moves in ahead of next system.

Aforementioned system prognosticated to move east from North Plains/S Canada
and swing a cold front through the area by late afternoon into the
evening hours. Latest nam12 has sped up timing a few hours from
previous run with front moving through in the 21z timeframe during peak
heating with middle level jet ramping up. 12z GFS/Gem/ECMWF remain
slower with frontal passage in the 00-06z timeframe. Severe threat remains
conditional and will hinge on timing of frontal passage which can be further
nailed down as Labor Day approaches. Lapse rates will remain meager
with marginal shear on the order of 20-30 kts but if destabilization
occurs...expect moderate instability which may be enough to trigger
a few stronger storms. Again heavy rainfall would be biggest threat
as Bountiful moisture transport continues in warm sector. Precipitation
will taper off during the day Tuesday as front departs and stalls
east-west in vicinity of Ohio Valley. Models differ a bit in details and placement of
several shortwaves riding along boundary in zonal upper level flow
through end of period. For now have kept with going dry forecast for
Wednesday through Thursday afternoon until details are better resolved.

Temperatures will remain near normal for the start of the period
before ramping up by end of the week with more muggy conditions
expected. Highs will generally be in the low 80s through Wednesday with middle
to upper 80s possible by end of the week. Overnight lows will be in
the 60s.

&&

Aviation...(for the 06z tafs through 06z Saturday night)
issued at 107 am EDT Sat Aug 30 2014

Mainly dry/VFR this morning as a warm front mixes north of the
area. There may be a brief period of MVFR br toward daybreak but
confidence remains too low for inclusion. Chances for scattered
convection increases this afternoon/evening as a weak low level
convergent boundary drops southeast into an increasingly
moist/unstable environment.

&&

Iwx watches/warnings/advisories...
in...none.
Michigan...none.
Ohio...none.
Lm...none.
&&

$$

Synopsis...steinwedel
short term...T
long term...ceo
aviation...steinwedel



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