Area forecast discussion
National Weather Service northern Indiana
752 PM EDT Thursday may 23 2013
Synopsis...
issued at 443 PM EDT Thursday may 23 2013
High pressure will build into the region from the northwest
tonight... and remain over the area through the weekend. This
will bring below normal temperatures and generally clear skies
over the next few days.
&&
Short term...(this evening through friday)
issued at 400 PM EDT Thursday may 23 2013
Surface cold front moved through the forecast area
this morning which brought a round of light rain through most of the
area. Rain showers and drizzle have continued dreary conditions
through the day due to cva ahead of a short wave trough digging into the
lower Great Lakes. These conditions were exacerbated in our
northwestern areas where an extensive marine layer has advected as
far inland as Elkhart and Kosciusko counties with drizzle and sub
1kft ceilings observed. Conditions will quickly improve across the
area from northwest to southeast as subsidence behind the sharp
trough axis...evident on water vapor crossing Lake Michigan
now...Ushers in mostly clear skies overnight.
These mostly clear skies tonight will allow temperatures to drop
into the upper 30s. Have little concern about frost given surface
winds between 6 and 8 kts overnight in the wake of the departing low
pressure system.
High pressure will keep skies sunny on Friday which will help
temperatures recover for a near 25 degree diurnal swing. Cold air
advection will cease near 12z and some 850mb warming will occur in
our western areas as subsidence increases with the approaching
ridge. Most model guidance for tomorrow is lower than current
forecast high temperatures...but elected to make only minor
adjustments to previous forecast high temperatures given
aforementioned full sun and building ridge.
&&
Long term...(friday night through thursday)
issued at 400 PM EDT Thursday may 23 2013
Quiet weather to begin this period as low level ridge axis extends
from western Great Lakes into the middle MS River Valley. Main forecast
challenge for the weekend into early next week will be resolving
amplitude of middle/upper level ridging and the possibility of embedded
convectively enhanced vorticity maximum progressing through the mean
ridge. A greater chance of convection for the Saturday/Sunday period
should remain to the west of the area across the middle MS River Valley
in better colocation with low level mass convergence associated with
low level jet. Thickness orientation/propagation vectors may support
east/southeast track of this convection into far west or southwest
portions of the forecast area in the Saturday night-Monday period.
Will continue to play it conservatively with this forecast with more
credence into Gem/ec idea of slower eastward progression of low
level thetae ridge and slower northward warm frontal push. Some
concern that GFS is overdoing convectively enhanced vortices given
recent biases and somewhat overdone low level moisture. Thus...will
maintain just some slight chance probability of precipitation across the far west/southwest
during this period. With local area in inflection zone of upper
level pattern...low level thermal advections will remain weak
through the weekend with only a slow moderating temperature trend
into the lower 70s by Monday.
More aggressive warm frontal push still expected late Monday into
Tuesday with ec preference...and highs to around 80 possible once
again by Tuesday afternoon. Maintained previous chance thunderstorms and rain probability of precipitation for
Tuesday/Tuesday night as warm front lifts north through the
area...with focus for additional thunderstorms and rain chances likely shifting north
of the area toward midweek as capping issues arise in warm sector.
Have kept Wednesday/Thursday dry at this time...although depending on warm
frontal progression may eventually need to add a chance across the
north. Medium range models in general agreement on upper ridge
amplification toward the end of the period downstream of next
amplified western Continental U.S. Trough. Did nudge CR allblend highs up a bit
for Wednesday/Thursday into the lower to middle 80s. South/southwest near surface flow
trajectories should limit lake cooling to northern portions of
Berrien County.
&&
Aviation...(for the 00z tafs through 00z Friday evening)
issued at 751 PM EDT Thursday may 23 2013
Slight delay in scour of stratocu deck across northern Indiana
per continued influence of slight 925mb cyclonic flow amid
saturated 900-850mb layer within subsidence inversion. A few hours
of fuel alternate conditions at ksbn then transition to high end
MVFR...in line with kfwa expected dominant trend where a deeper
mixed layer/lack of dominant marine layer has helped to maintain
better flight conds through the day. With time...gradual
transition to anticyclonic low level flow as upstream surface high
centroid near Minnesota arrowhead continues to drop southeastward into yoop along with
persistent subsident/dry air advection to assuredly yield
substantial clearing across northern in by about 04 UTC.
&&
Iwx watches/warnings/advisories...
in...beach hazards statement through Friday evening for inz003.
Michigan...Beach hazards statement through Friday evening for miz077.
Ohio...none.
Lm...Gale Warning until 8 PM EDT this evening for lmz043-046.
&&
$$
Synopsis...kg
short term...Bentley
long term...marsili
aviation...Murphy
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