Area forecast discussion
National Weather Service Indianapolis in
731 am EDT Sat may 25 2013
Update...
the near term section has been updated below.
&&
Synopsis...
issued at 220 am EDT Sat may 25 2013
High pressure over the Great Lakes will drift east of Indiana
today and continue to provide dry...cool and pleasant Spring
weather for central Indiana through tonight. A warm front will
approach Indiana from the west on Sunday as a upper level weather
disturbance arrives in the region also. This will result in
clouds and chances for showers on Sunday.
Precipitation chances will continue on Monday and Monday night as
the warm front lingers in the area and weak upper level
weather disturbances continue to push into the area. Temperatures
will continue to moderate each day...with highs getting warmer
each day.
&&
Near term /today/...
Issued at 731 am EDT Sat may 25 2013
Increased cloud cover today based on current trends as seen on
satellite imagery. Radar shows some echoes moving into the forecast
area...but for the moment believe lower atmosphere is too dry for
anything to reach the ground. Will continue to monitor to see if
sprinkles need to be added...cloud cover increased...or temperatures
adjusted.
Previous discussion follows...
Surface analysis early this morning shows a broad area of high
pressure stretching from the Great Lakes south across Indiana and
Ohio into the Kentucky and Tennessee. Cool north winds were in
place across the forecast area with dew point temperatures in the dry
lower 40s.
The high will continue to provide dry weather across Indiana
today. Forecast soundings remain quite dry...but do hint at
saturation aloft by late this afternoon. Lower levels remain very
dry and Gulf continues to be cut off as we continue to be under
the influence of the strong high.
Will aim to the warmer side of the guidance highs as the strong
may sun provided plenty of good heating yesterday and see no
reason why we wont have a similar day today.
&&
Short term /tonight through Monday night/...
Issued at 220 am EDT Sat may 25 2013
Models are in pretty good agreement and will use a blend. Main
forecast challenge will be probability of precipitation.
GFS and NAM continue to suggest several ridge riding short wave
will be pushing into the Ohio Valley starting on Sunday afternoon
and again on Monday night. The lower levels show a warm front
passing through the state on Sunday and Monday will provide a
focus for lower level convergence. Forecast soundings show
increasing deep moisture by 00z Sunday with a saturated column at
that time. 305k GFS isentropic shows good upglide pushing into the
SW parts of Indiana on Sunday afternoon and then across the whole
forecast area on Monday. Specific humidities get quite moist
reaching values in excess of 6 g/kg. However questions remain as
to where this moisture will arrive from...since the Gulf remains
blocked. Thus given the factors that are available to provide
forcing will keep some low probability of precipitation in the forecast from Sunday
afternoon through Monday night. At this time given the limited
moisture sources and the albeit weak forcing...any precipitation amounts
should remain light. Given the expected clouds and warm air
advection through the period will trend lows warmer than mavmos
and stick close on highs.
&&
Long term /Monday night through Friday/...
Issued at 220 am EDT Sat may 25 2013
Ensembles in good agreement with the long wave features during this
period. Upper ridge currently over the plains is expected to
gradually shift east through into the Midwest and Ohio Valley by the
middle of next week...reaching the East Coast by next Friday.
Appears there is still a potential for embedded short wave troughs
to ride through the ridge on Tuesday. Will keep some small probability of precipitation in
the forecast for Tuesday.
By next Wednesday and Thursday...ensembles suggest the upper ridge
will build more aggressively over the area as deep troughing
develops over the West Coast and rockies. This should help to cap
off precipitation chances later next week...with the ensembles
suggesting little threat for precipitation Wednesday and Thursday.
Will go dry during those periods.
By next Friday...some of the ensembles push the ridge far enough
east to bring in a precipitation threat from a system that may be
moving through the northern plains. Will keep next Friday dry for
now...but probability of precipitation may need to be added in the future if things trend
towards the wetter solutions.
&&
Aviation /discussion for the 251200z tafs/...
issued at 645 am EDT Sat may 25 2013
Ceilings above 050...unrestricted visibility...surface winds at or
below 7 kts expected at the taf sites through 260000z.
&&
Ind watches/warnings/advisories...
none.
&&
$$
Synopsis...puma
near term...puma/50
short term...puma
long term....jas
aviation...jas
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