Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus61 Kiln 181041 
afdiln

Area forecast discussion
National Weather Service Wilmington Ohio
641 am EDT Fri Oct 18 2019

Synopsis...
high pressure centered over the region will provide dry and
tranquil weather conditions today and tonight before a weak
system moving through the Ohio Valley brings a chance for some
isolated to scattered precipitation into the area for Saturday
night. Warmer and wetter conditions are expected Monday into
Monday night before a cold front Ushers in slightly cooler air
by Tuesday and beyond.

&&

Near term /until 6 PM this evening/...
most of the stratocu that had persisted across the iln forecast area
earlier Thursday evening has since dissipated, yielding mainly
clear skies across pretty much the entire local area. That has
set the stage for a little bit of River Valley fog in south-
central Ohio per GOES-16 nighttime microphysics imagery. Outside
of the river valleys, however, the mainly clear skies and light
winds have allowed temperatures to drop into the low to mid
30s. Have seen a few spots dip to 32-33f, but this seems to be
confined mainly to the rural areas of east-central Indiana and
west-central Ohio. Most locations will see temps bottom out
between 33f (west) and 37f (east) by daybreak. This undoubtedly
will yield widespread frost formation in some spots -- and
already seeing that here at the office in Wilmington where the
temp has dipped to 36f as of this writing. However, despite a
few isolated locations falling to the freezing mark, do think
that the prevalence of such an occurrence is low/isolated
enough as to not warrant an upgrade to a freeze warning even in
the "cool" spots.

After a frosty start to the day, abundant sunshine will allow
temps to reach between 60f-65f by late afternoon as surface high
pressure traverses the region. A gradual shift from
northwesterly winds to more east-southeasterly winds will occur
during the daytime period as the high center migrates east.
Other than a few passing cirrus, expect clear skies through the
day.

&&

Short term /6 PM this evening through 6 PM Saturday/...
another tranquil night is in store tonight -- although perhaps
not quite as cool for some spots (particularly in the west).
Still anticipate lows to drop into the mid to upper 30s, with
central Ohio and south-central Ohio being the cool spots.

Debated going with a frost advisory for eastern zones for
tonight but decided to hold off as to not promote confusion with
current frost advisory out area-wide. Will likely need an
advisory for a small subset of the area for later tonight but
will re-address once the frost from this morning Burns off. Will
maintain highlight in severe weather potential statement for tonight/early Saturday morning.

By Saturday, several impulses of midlevel energy will track
northeast into the Ohio Valley as the remnants of a tropical
system push across the Tennessee Valley. Better forcing for
ascent associated with a midlevel short wave will arrive by Saturday
evening, but we will likely see some difficulty in any precip
reaching the ground initially -- owing to the antecedent drier
bl conditions entrenched across the region. Any substantial
(chance pop) precip potential will likely hold off until
Saturday night/after the conclusion of the short term period.

Even with a bit more cloud cover infiltrating the region from
the South/West by late Saturday afternoon, expect highs to top
out a degree or two either side of the 70-degree mark.

&&

Long term /Saturday night through Thursday/...
couldn't quite remove all chances for scattered showers on Sunday as
the combination of a shortwave trough and remnants of a possible
tropical cyclone work northeastward up the Appalachians. Model
guidance continues to suggest above average pwats move in from the
south late Saturday night and into Sunday morning with few scattered
showers possible. There is also some quantitative precipitation forecast support from both ensemble
groups of the GFS and European model (ecmwf) so still not completely confident of no
rain across the area. The best chances are forecast to be across
southeast portions of the forecast area. Rain chances quickly move
to the east Sunday afternoon as mid-level ridging builds in. Clouds
clear and warm air advection helps push temperatures into the low to
mid 70s for Sunday afternoon.

Mid-level ridging begins to move eastward during the day on Monday
as the next deep trough moves into the central US. An initial
shortwave rapidly intensifies an area of low pressure over the
Midwest during the day on Monday, pushing a strong cold front
eastward toward the forecast area Monday evening. This cold front
eventually moves through late Monday night, bringing increased
chances for showers and embedded thunderstorms. Most recent 00z
European model (ecmwf) lowered overall quantitative precipitation forecast quite substantially as the low pressure
occludes over the Midwest. Overall support for enhanced lift along
the front is rather lacking until a secondary shortwave moves
through the base of the trough on Tuesday. The cold front has pushed
well off to the east by this time, therefore missing the window of
opportunity overnight on Monday. The secondary source of lift keeps
some shower chances for the first part of the day on Tuesday, mainly
across eastern zones, but overall accumulation expectations are
rather limited at this time. Still closely monitoring chances for
severe weather late Monday night as the cold front is associated
with a very intense area of low pressure, but overall, confidence is
decreasing given the occluding low and timing of the two shortwaves.

Ahead of the front, highs on Monday will push into the mid 70s. Good
cold air advection on the back side of the front will keep highs on Tuesday in the
upper 50s to lower 60s.

Weak mid level ridging will develop across the region through the
day on Wednesday before some additional short wave energy approaches
from the northwest through the day on Thursday. This will eventually
help push another cold front and a chance of showers southeast
toward our area but this will likely hold off until at least
Thursday night and into Friday. Temperatures for the end of the
extended are expected to be near normal (highs in the mid 60s, lows
is the lower 40s).

&&

Aviation /12z Friday through Tuesday/...
VFR conditions will prevail through the taf period with the lone
exception being the possibility of some brief MVFR vsbys in the
several hour period around sunrise Saturday morning due to br
at kluk. Other than some passing cirrus, do not expect much in
the way of cloud cover during the afternoon hours today. Clear
skies are expected again tonight with more River Valley fog
possible.

Light west-northwesterly winds of 3-5kts will go light and
variable before going more northeasterly and eventually east-
southeasterly by the evening through the overnight. Winds
should generally remain about 5kts or less everywhere through
the period.

Outlook...MVFR conditions and gusty winds to 35kts will be
likely Monday into Monday night.

&&

Iln watches/warnings/advisories...
Ohio...frost advisory until 10 am EDT this morning for ohz026-034-035-
042>046-051>056-060>065-070>074-077>082-088.
Kentucky...frost advisory until 10 am EDT this morning for kyz089>100.
In...frost advisory until 10 am EDT this morning for inz050-058-059-
066-073>075-080.

&&

$$

National Weather Service Glossary of Abbreviations