Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wilmington Ohio
649 PM EST Sat Mar 8 2014
a weak cold front will continue to move southeast through the Ohio
Valley this evening. A ridge of high pressure will quickly build
back into the area overnight. The high will move east just as
quickly on Sunday with a general southwesterly flow at the surface
expected to warm the region up for early next week.
Near term /until 6 am Sunday morning/...
cold front is currently northwest of the I-71 corridor and the
majority of precipitation found with it is northwest of metropolitan
Columbus. Expect rain to start out for much of central Ohio and be
generally light...mixing with and changing to snow after an hour
or two. At this time...accumulating snow is not expected with this system
and any precipitation should be light in nature. Northerly winds
bringing in cooler air will usher in cooler air tonight and Sunday
in the Post-frontal environment.
Remainder of County Warning Area has slight chances of rain or rain/snow this
afternoon and evening. One caveat here is that the upper level
trough helping spark the precipitation is going to be over the region
towards midnight. The increased upper lift combined with the
proximity of the surface front just southeast of the County Warning Area at this
time has a heightened area of snow or rain/snow over southeastern
County Warning Area later this evening. Once again...precipitation should remain light
and no accumulations are expected even if the ptype happens to be
Short term /6 am Sunday morning through Monday night/...
while temperatures on Sunday will definitely have a Post frontal
chill to them and only top out in the 40s...flow will turn
southwesterly and a continued warmup to Spring-like and above
normal temperatures is expected from Sunday night Onward.
Zonal west-northwest flow aloft and west-southwest at the surface will prevail and let
temperatures moderate under fair sky conditions. Expect a 500 mb short wave to track
north of the region and bring an increase in cloud cover Monday
night for northern sections of County Warning Area. This energy will prime a
convergent boundary over the Ohio Valley Monday night and a
surface boundary/warm frontal processes aloft will increase the
chance of a passing light shower at this time.
Long term /Tuesday through Saturday/...
models begin the period with a front straddled across the region.
The GFS appears to the farthest south with the fnt positioning it near
the Ohio River at 12z Tuesday.
500 mb trough in the northern stream digs down out of Canada Tuesday and into
the upper MS valley Tuesday night. In response...a low pressure
center develops on the fnt and rides eastward towards the forecast area. The
GFS/European model (ecmwf) take the low across Kentucky...while the Canadian hemispheric
model is stronger and quicker as it takes the low across central
Ohio. The 00z European model (ecmwf) had been much warmer with the thermal fields
than the GFS...but the 12z European model (ecmwf) has now trended towards the cooler
GFS. Will run a GFS/European model (ecmwf) blend for the storm system Tuesday night
into Wednesday. Upped probability of precipitation late Tuesday night to categorical across
the southern half of the forecast area. Temperatures should be warm enough for
the precipitation to begin as rain...but then as the night progresses colder
air will filter in and the rain/snow line will dip south.
As the low quickly passes to the east Wednesday morning...critical
thicknesses will continue to drop south and the rain/snow line will
follow them. Went with an early high on Wednesday with temperatures
falling during the afternoon.
Some convective cold air advection snow showers will be possible Wednesday night on
the backside of the system.
By Thursday high pressure will build across the Ohio Valley. By the
end of the week a low will pass across the northern Great Lakes...but it
will drag a cold front into the region late Friday night into Saturday.
Right now it looks like the moisture with the front will be
limited...so left the forecast dry.
Tuesday will be the end of the Spring warm up as highs push into the
middle 50s to lower 60s. As mentioned above the storm system Tuesday
night into Wednesday will bring cold air back into the region. Lows
Tuesday night will range from around 30 in the northwest to around 40 along
the Ohio River. Temperatures on Wednesday will go up a few degrees
before beginning to fall back in the afternoon. Highs on Thursday
are forecast to only reach the middle 30s to lower 40s. Thanks to high
pressure on Friday temperatures should be back up around normal.
Aviation /00z Sunday through Thursday/...
MVFR ceilings and visibilities will spread across all terminals by
early in the taf period. Expect some IFR conditions as well at
most locations at least through 06z. Should hold on to MVFR until
around 12z when conditions should start to improve with clouds
lifting and scattering and visibility restrictions ending. Once
conditions become VFR they will remain that way through the end of
the taf period with few if any clouds during the latter portion of
the forecast. North northwest winds will slowly diminish tonight
and then back to the southwest on Sunday.
Outlook...MVFR ceilings and visibilities likely Tuesday night