Scientific Forecaster Discussion
Area forecast discussion
National Weather Service northern Indiana
829 PM EDT sun Mar 16 2014
issued at 103 PM EDT sun Mar 16 2014
Unseasonably cold temperatures can be expected today and tonight
as cold Arctic high pressure noses into the region. Other than a
few passing flurries...dry conditions will be in store for the
region into Tuesday. Look for afternoon highs only in the middle
20s north to lower 30s south. Lows tonight will drop into the
single digits north and middle teens south.
Short term...(this evening through monday)
issued at 347 PM EDT sun Mar 16 2014
Low pressure will track across the Gulf states with influence from
this system reaching well north into the upper Ohio Valley. Remnants
of baroclinic zone was continuing to shift south and was resulting
in low clouds lingering across southern parts of the County Warning Area and a few
areas of flurries. Skies will continue to clear from north to south
with southern areas not fully clearing until middle evening or later.
This will allow for a quick drop in temperatures across the north as
subsidence continues to push in and pressure gradient relaxes. Lows
will fall into the single digits across the north half of the area. MOS
guidance continues on the cold side with lows in some areas near
zero. Have lowered overnight lows somewhat following adjusted Euro
guidance which has been verifying best for last several forecasts.
Quiet start to the work week with high pressure still in control but
drifting east. A bit of cloud cover will spill in from increasing
warm air advection to the west that will clip northern areas. Still shouldn't
amount to much more that partly to mostly sunny skies. Challenge
remains how warm with afternoon highs get with already noted warm air advection
underway. While some guidance brings temperatures up several degrees
tomorrow afternoon will remain conservative with increasing cloud
cover in the afternoon.
Long term...(monday night through sunday)
issued at 347 PM EDT sun Mar 16 2014
A couple of shortwaves will impact our County Warning Area this period. First system
was off the Pacific northwest coast this afternoon and is expected to dig southeast
into the Central Plains by Tuesday and then lift NE across the Great Lakes on
Wednesday. Dry weather with a warming trend expected ahead of this system. With
light southeast gradient winds expected Monday night and some middle level warm air advection
clouds... consensus MOS lows seemed reasonable with lows ranging
from the upper teens NE to the u20s SW. Although surface winds will be
southeasterly Tuesday... gradient will strengthen and with considerable
sunshine and weak warm air advection... leaned toward warmer end of guidance with
highs ranging from the m40s NE to the u50s SW.
Still a fair amount of timing difference on frontal passage Tuesday night/Wednesday
with European model (ecmwf) a good 6hrs slower than GFS/Gem/NAM. Stuck with model
blend for temperatures which adjusted mins down across the northwest. Limited
moisture available for this system should be compensated by strong
dynamics and expect most if not all of the area will at least have
some light rain showers with the cold front... however with timing
differences remaining... held onto just chance probability of precipitation for most of the
area for Tuesday ngt/Wed. A few Post frontal wrap around snow showers
possible into Wednesday night across northern portion of the area. Modest cold air advection
behind this system and some gradient winds probably staying up
through the night should limit temperature falls with lows expected
in the u20s/l30s.
Next shortwave expected to move through the area Friday bringing
another chance of showers. Temperatures will warm up to near normal ahead of
the system by Friday... followed by colder conditions Saturday as
another Arctic high builds southeast into the north central Continental U.S..
Aviation...(for the 00z tafs through 00z Monday evening)
issued at 828 PM EDT sun Mar 16 2014
VFR conds expected through the period as ridging persists across the area.
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