Area Forecast Discussion
Issued by NWS Wilmington, OH-- Remove Highlighting --
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FXUS61 KILN 211725
Area Forecast Discussion
National Weather Service Wilmington OH
Issued by National Weather Service Jackson KY
1225 PM EST Sat Jan 21 2017
Temperatures will remain well above normal today into Sunday as
warm southerly flow persists across the region. A developing upper
level low pressure system will move across the southeastern
United States Sunday into Monday, bringing an increasing chance of
rain to the area. This will also be accompanied by somewhat cooler
temperatures for the start of the work week.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Mid and high level clouds continue to overspread the area, with
a bit more thickening in the south-southeast. Temperatures are
responding nicely to southerly flow, particularly in the south.
Radar mosaic does show some very light echos moving northeast
across our southeastern zones, but expectations are that nothing
is reaching the ground. HRRR has consistently suggested the
potential for some isold shower activity across our southeast
later this afternoon and based on current trends this seems
reasonable as there is an occasional uptick in intensity with
those radar echoes. Did expand our forecasted slight pop just a
bit further northwest based on recent runs and trends in the
HRRR. Inherited temperatures from previous shift looked very
good. Thus afternoon highs in the low to mid 60s appear on
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
Quite a bit of uncertainty arises in the forecast tonight into
Sunday as the models continue to struggle with exactly how to
handle the developing upper level low that will move from the
Southern Plains to the East Coast through the rest of the weekend.
There are then additional uncertainties with the timing and
placement of mid level energy rotating around the upper low.
The 00Z NAM seems to be somewhat of an outlier with an elongated
upper low extending up toward the southern Great Lakes by Sunday
night. Meanwhile the 00Z ECMWF and CMC are farther south than the
00Z GFS with the track of the upper low across the southeastern
United States through the day on Sunday. The ECMWF is pretty much
keeping our area dry through the day on Sunday while the
remaining models are spreading a pretty good slug of moisture up
across our area. This seems to be backed up by the NCAR ensemble
forecast with most of its members spreading precipitation up into
our area through the day on Sunday. Will therefore go ahead and
trend that way and have high chance to likely pops developing
across our area. Some instabilities will also spread up into our
area through the day on Sunday so will go ahead and allow for at
least a chance of thunder across our southern areas for mainly
Sunday afternoon. Temperatures on Sunday will again be mild with
highs in the upper 50s to around 60 degrees.
Additional uncertainties arise for Sunday night into Monday as
the upper low pivots up across the mid Atlantic States. All of
the models are in pretty good agreement that there will be a
pretty heavy swath of precipitation somewhere along the pivot
point with the general consensus that this will primarily be
southeast of our FA. That being said, a few of the GEFS members are
showing 1.5 to 2 inches of rain across parts of our southeast
Sunday night into Monday and the parallel run of the GFS is
actually cranking out over three inches of rain at PMH. Based on
all of the timing and placement issues, there is quite of bit of
uncertainty here, but will go ahead and include a mention of some
heavy rain in our HWO product for our southeast.
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Cooler conditions will continue into Tuesday as clouds remain in
place, with low-level winds beginning to shift to the west, and
eventually the southwest. A narrow ridge will move east through
the area on Tuesday night into Wednesday, shifting the pattern
firmly to warm advection for a relatively short period of time. It
is at this point in the forecast that confidence in specifics
becomes poorer, with increasing spread between the timing and
magnitude of features between GEFS members and between the 12Z GFS
/ 12Z ECMWF. However, there is high confidence in the general
pattern, with a surface low and upper trough moving through the
Great Lakes. This will allow a cold front to move east through the
Ohio Valley at some point on Wednesday, though limited moisture
will limit the chances for precipitation. Ahead of the front, the
pressure gradient will increase, and some slightly gusty
conditions may occur -- along with temperatures well above normal.
Max temps were increased for Wednesday, slightly above the model
consensus. Behind the front, cooler conditions through the end of
the week. There is a very large amount of spread in the timing of
additional precipitation chances on Thursday and Friday, as a
general pattern of broad troughing moves over the Great Lakes and
Ohio Valley through the end of the week. Temperatures during the
low end of the diurnal cycle may be cool enough to support some
snow, depending on when precipitation occurs.
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
Expecting generally VFR conditions for area terminals through
the bulk of the first 18 to 24 hours of the TAF period. However,
light rain and lower CIGS will overspread much of the area from
the south through the day Sunday.
Initial disturbance moving across the deep south is responsible
for the mid and high level cloudiness over the area. There are
some very light echoes showing up on the radar mosaic and
models do suggest the potential for some isold shower activity
generally southeast of a line from CVG to CMH this afternoon and
across our north later tonight. Consequently there should be
some areas of virga across our southeast at a minimum along with
the possibility of some isold shower activity. Fairly confident
that CVG, LUK, DAY will remain precipitation free this
afternoon. However, will include mention of some showers in the
vicinity of ILN, CMH, and LCK. Shower activity may continue to
affect portions of the forecast area tonight, but generally
across the north.
A more significant storm system and surface low pressure center
will ride up into the lower Ohio Valley and Tennessee Valley
region Sunday. With decent model agreement in details of
sensible weather, confidence is increasing that rain will
rotate northward across the area through the day Sunday,
affecting CVG/LUK by mid morning and our more northern terminals
by early afternoon.
Aforementioned storm system moving through the area Sunday
night and Monday will keep our weather unsettled. There appears
to be a lull in the weather Tuesday and Tuesday night. Then a
cold frontal boundary will bring showers back into the area by
OUTLOOK...MVFR/IFR ceilings and visibilities possible Sunday
through Monday, then again Wednesday morning.