Area Forecast Discussion
Issued by NWS Cleveland, OH
FXUS61 KCLE 062020
Area Forecast Discussion
National Weather Service Cleveland OH
320 PM EST Tue Dec 6 2016
An area of low pressure over the region will weaken as it moves
east overnight with a weak cold front trailing it. High pressure
will build in behind the cold front bringing dry and cooler
conditions for Wednesday. An upper level trough will move north of
the region with some much colder air expected Thursday. This will
generate lake effect snowfall into Saturday.
.NEAR TERM /THROUGH TONIGHT/...
An area of low pressure over southern Ohio will continue northeast
tonight. Rain will continue along and ahead of the track of the
center of the low this evening. Rain has already cleared the I-75
corridor and will continue to clear from west to east. Rain will
linger a bit longer in NW PA with some areas potentially seeing some
mix of rain and snow after midnight in the highest hills. Otherwise,
behind the rain, winds will shift to the west and some colder air
will advect into the region. Could see some breaks in the clouds to
the west and the temperatures out there could dip the lowest into
the mid 20s.
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
Wednesday will be fair weather with high pressure over the region.
Attention then turns to the lake effect snow event taking shape
for Thursday through Friday Night. Cold air advection will kick in
Thursday resulting in steady if not cooling temperatures during
the day with wind chills in the teens. The H850 temperatures will
plummet from the +4C of today to -12 to -14 C by Thursday
afternoon yielding very high delta t over the lake. In the DGZ
there is deep low level moisture along with respectable omega
values for a measurable lake effect snow event. At this time the
greatest potential for accumulating snow looks to start Thursday
afternoon through Friday Night. Instability increases along with
upper level support for some convective thunder possible Thursday
Night. The flow direction will fluctuate from a WSW, to W, NW, and
then back to WSW at which point the event will lift out of the
area Saturday morning. A lake effect snow watch has been issued
for Thursday morning through Saturday morning. Inversion heights
will be favorable and quite high Thursday night at around 9-11 kft
agl before lowering to around 5-7 kft agl Saturday. The overall
conditions favor several snowbelt areas receiving over 6" with the
potential for over a foot in the higher terrain of NW PA.
.LONG TERM /SATURDAY THROUGH TUESDAY/...
Lake effect snow will be ending at some point on Saturday as
southwesterly winds shift any remaining bands back up the lakeshore
into Western NY. There should then be a brief lull in precipitation
Saturday night before the arrival of the next system. The GFS and
ECMWF have come into better agreement with regards to the initial
onset of precipitation beginning Sunday afternoon, but they still
differ significantly with how long the precipitation will stick
around. The ECMWF brings up an area of low pressure behind the cold
front Sunday night into Monday with plenty of moisture, while the
GFS is much more progressive. The precipitation type Sunday is
trending more towards mostly snow, though a mix with or even change
over to rain at some point Sunday afternoon cannot be ruled out,
especially across the southwestern portion of the CWA. Overall,
confidence remains low with regard to the timing of this storm
system. The exact timing will have an impact on the precipitation
type, so confidence with regards to that is also low. Yet another
storm may affect the region Tuesday.
.AVIATION /18Z Tuesday THROUGH Sunday/...
Light rain is currently across the entire area with widespread
MVFR/IFR conditions. Expect this to continue through the afternoon
hours. Rain will end from west to east from mid afternoon into
the evening hours. The lower clouds will attempt to lift in the
wake of a weak cold front that will cross the region overnight.
Easterly winds will gradually shift to the southwest through the
day. Winds will then become westerly in the wake of the cold
front this evening into the overnight.
OUTLOOK...Non-VFR into Wednesday in rain/snow showers. Lake
Effect snow develops Thursday into Friday with non-VFR expected,
especially across NE OH/NW PA.
Southeasterly winds this evening will shift around to the west
overnight. Before winds shift around to the west, there will be
strong enough downslope winds to around 20 knots off the Erie lake
shore, so will start the Small Craft Advisory in this area at 00Z.
Farther west, the westerly winds will increase to 20 to 25 knots by
03Z, so the Small Craft Advisory goes into effect at that time for
the rest of Lake Erie. The Small Craft Advisory will continue
through 12Z Friday for the western basin, and until 00Z Saturday
elsewhere. There will likely be a little lull in the winds Wednesday
night and they may fall below Small Craft Advisory conditions for a
time, but will pick back up to 20 to 25 knots again by Thursday
morning, so just went with a continuous advisory.
OH...Lake Effect Snow Watch from Thursday morning through Saturday
morning for OHZ012>014-089.
PA...Lake Effect Snow Watch from Thursday morning through Saturday
morning for PAZ001>003.
MARINE...Small Craft Advisory from 7 PM this evening to 7 PM EST Friday
Small Craft Advisory from 10 PM this evening to 7 AM EST
Friday for LEZ142>144.
Small Craft Advisory from 10 PM this evening to 7 PM EST
Friday for LEZ145>147.