Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wilmington Ohio
959 PM EDT Friday Mar 14 2014
gusty southerly winds will occur ahead of a cold front that moves
through tonight. A brief period of precipitation will be possible
with this frontal passage. High pressure will briefly build in
Saturday before a low tracking across the Tennessee Valley spreads
wintry precipitation across the area on Sunday and Sunday night.
Near term /until 6 am Saturday morning/...
wind-based surface analysis would indicate that the cold front is
now in the northwest corner of the iln County Warning Area...with westerly winds
reported in Darke County. Radar echoes in the southern County Warning Area have
not reached the surface...but the main band of rain showers along
the front has finally developed...and appears to be timing out
nicely with the latest rap13 model runs. Given the high bases and
big dewpoint spreads...it seems likely that even this
precipitation may not be as intense as the dbz values would
indicate (most ob sites are still reporting 10sm under the
echoes). Probability of precipitation were adjusted to account for current trends...with
quantitative precipitation forecast kept under a tenth of an inch. Temperatures have remained
ahead of the trace tonight...and min temperatures were raised slightly.
However...temperatures will finally begin to fall a bit more once the
front has passed (and skies begin to clear later in the overnight
Short term /6 am Saturday morning through Sunday night/...
in split middle level flow area of confluence to work across Ohio. Weak
surface high pressure to build east across the region Sat/Saturday
night. Saturday should start out mainly clear early with an increase
in middle/hi level clouds during the day. Temperatures expected to be
near normal...ranging from the middle/upper 40s northwest to the middle/upper 50s
Expect to see middle/hi level clouds thicken Saturday night with
precipitation staying to our south. Lows expected to range from
the Lower/Middle 20s northwest to the Lower/Middle 30s south.
Southern stream energy to induce a surface low which tracks through the Tennessee
Valley sun/Sun night. NAM is furthest north with surface low track and
therefore has precipitation spreading further north and more warm air aloft.
GFS takes the surface low far south across the northern Gulf states...keeps
precipitation mainly snow and suppressed to south. Sref mean and the European model (ecmwf)
solutions offer more of a compromise. Complex situation with two
pieces of middle level energy phasing and at this timeframe the
numerical models typically struggle on resolving these situations.
Therefore will trend the forecast solution toward a blended compromise at
this time. Will allow precipitation to develop across the south in
response to isentropic lift by late morning and then spread north
during the day. For precipitation type will allow for a mix in the far south
and snow across central and north. Potential exists for several
inches of accumulating snow sun/Sun night.
Will continue to highlight this potential in the severe weather potential statement product. Expect
below normal highs Sunday with low level NE flow. Highs to range
from near 30 northwest to the upper 30s southeast. Lows Sunday night to range
fro the middle teens northwest to the upper 20s southeast.
Long term /Monday through Friday/...
kept a chance of snow in the east Monday morning when a shield of
moisture associated with low pressure will be moving east as the low
reaches the Atlantic Ocean. A ridge of high pressure and dry weather
will follow the low for Tuesday. A strong cold front coming from the
west will likely push a band of showers across the area late
Wednesday to early Thursday. High pressure and a dry weather regime
appear to be in store for late Thursday through Friday.
Chilly highs close to 40 are expected for Monday behind the low.
Moderation to near normal 50s can be anticipated by Wednesday as
warm advection takes hold ahead of the cold front. Highs may slip
back to slightly below normal 50 Thursday and Friday in the wake of
the cold front.
Aviation /02z Saturday through Wednesday/...
as low pressure moves away from the region tonight...winds will
continue to gradually diminish in intensity. A weak cold front
will cross through the region...allowing winds to shift from
southwesterly to westerly.
Along the front...there still appears to be some chance for rain
showers to develop. Prevailing showers were left in the tafs...but
with the expectation that this will have very little impact to
aviation...with conditions remaining VFR where and if showers do
Skies are expected to be mostly clear by early Saturday
morning...with high clouds gradually moving in during the day. West-northwest
winds will not be nearly as strong as the winds were today...with
sustained winds of around 10 knots and any gusts remaining under
Outlook...MVFR/IFR ceilings and visibilities are possible from
Sunday afternoon into Sunday night. MVFR ceilings may linger into
Monday. MVFR conditions are possible Wednesday.