Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Indianapolis in
1000 PM EST Friday Feb 12 2016
The near term section has been updated below.
issued at 330 PM EST Friday Feb 12 2016
We will transition from a cold pattern to mild pattern over the next seven
days as strong upper trough over Ontario...eastern Great Lakes and New
England moves on to the east and is replaced by a broad upper ridge
over much of the U.S.
In near term...a clipper which brought light snow showers today will move
quickly eastward. Lake effect snow showers are possible over northeast
sections through early Saturday as a very cold northwest flow picks
up some moisture off of Lake Michigan. A stronger disturbance will bring
a likelihood of snow to most areas Sunday and Sunday night. Then a couple of
other disturbances will bring chances of mixed precipitation or snow Monday
through the middle of next week and a chance of rain by day 7.
Near term /tonight and Saturday/...
issued at 1000 PM EST Friday Feb 12 2016
Going forecast in very good shape. Made minor tweaks to the sky
grids but otherwise we are on track. Previous discussion follows.
Issued at 330 PM EST Friday Feb 12 2016
Light snow showers have increased this afternoon as an upper disturbance
moves east southeast across our region. The snow showers should end over
western and southern sections by evening...but will continue east of a
Frankfort to Indianapolis and Shelbyville line overnight and some areas
early Saturday as a northwest flow off of Southern Lake mihcigan produces
scattered light snow showers. Accumulations up to a third of an inch are
possible over the far northeast...while little or no accumulation occurs
Other issues tonight will be low temperatures in the single digits and wind
chills of around 10 below late tonight. Raised temperatures slightly in the
far northeast...otherwise stayed close to a MOS blend on temperatures.
Saturday will be cold with highs in the teens...but with temperatures
approaching 20 far south which was near a MOS blend. High pressure over
the upper Midwest Saturday morning will build to northern Indiana late Saturday.
Short term /Saturday night through Monday/...
issued at 330 PM EST Friday Feb 12 2016
Main focus will be snow chances and accumulations Sunday into Monday
as a could of systems move our way.
High pressure over northern Indiana and the Great Lakes Saturday
evening will move quickly eastward as a couple of upper disturbances
move our way. Warm advection ahead of this system will cause precipitation
to spread into our region by Sunday morning. Started slight chance probability of precipitation
over southwest sections after 09z Sunday and elsewhere had probability of precipitation increasing
to likley's during the day Sunday.
Models indicate one disturbance will move east across the southern Great
Lakes as another disturbance causes a low pressure system to develop over
the lower Mississippi Valley Sunday night. Most of our weather will be
from the northern system which will produce a couple inches of snow Sunday
and Sunday night. Precipitation from this system will gradually end from
Monday over northern and western sections. But will keep low chances
across our south and east through the short term.
Models indicate some warming by Monday...but GFS seems a bit too warm and will
lean towards the cooler NAM on Monday. But this warming may still be
enough for mixed precipitation or low chances of rain Monday afternoon
in the south.
Long term /Monday night through Friday/...
issued at 234 PM EST Friday Feb 12 2016
One wave is exiting the area as the long term starts but it is
quickly followed by another wave bringing more precipitation chances to
central Indiana for Tuesday and Tuesday night. With high
variability in ensembles and cips analogs not keying in on any
significant event accepted the initialization low chance probability of precipitation for
that time frame. Could see enough warming for Tuesday to be a mix
of rain and snow for much of the area switching back over to snow
Tuesday night. A warming trend will ramp up from Wednesday through
Friday with highs climbing from the middle 30s to the middle 50s.
Aviation /discussion for the 130300z kind taf update/...
issued at 920 PM EST Friday Feb 12 2016
No changes made to the forecast at this time. Previous discussion
Snow shower activity currently in the process of pushing off to the
southeast of the terminals...and should be gone by issuance time.
Otherwise...expecting VFR ceilings around 040 to gradually scatter
out with time this evening. Pressure rise maximum still off to the
northwest...so should see surface gusts around 25 kts from 300-320
degrees linger well into the evening hours before settling in the
10-15 knots range.