Area Forecast Discussion

FXUS61 KCLE 131725
Area Forecast Discussion
National Weather Service Cleveland OH
1225 PM EST Tue Nov 13 2018
...18z Aviation Forecast Update...
Low pressure over the Delmarva Peninsula will move up the East 
Coast today. High pressure will build in from the west over the 
lower Great Lakes by Wednesday. The high will move northeast to 
Maine by Thursday. Low pressure will move northeast to the Ohio 
Valley by Thursday and then shift to the East Coast by Thursday 
night. High pressure will build up the Appalachian Mountains 
Saturday with a cold front moving east across the local area 
Saturday night.
There are no significant changes to the on going forecast this
morning. We have updated cloud cover and scattered flurries or
light snow shower chances for the rest of the day for areas east
of Interstate 77. The Hi-Res HRRR and NAMnest have a good handle
on the lake effect snow bands developing later today into
tonight for the Snowbelt Region where several inches of snowfall
is likely.
Original Discussion...
Precipitation that was suppose to be associated with the low
pressure system that is currently over the Delmarva Peninsula
continues to have a tough time materializing across the local
area this morning. One factor has been the considerable dry air
in place but that appears to be moistening up over the last
several hours. One more shot of moisture is expected to stream
northeast over the next few hours. So, will bank on
precipitation from this activity to hit the eastern portions of
the forecast area early this morning. Pulled back on the QPF
amounts across the area due to the lack of current precipitation
and diminishing threat western two thirds of the area.
Winds are shifting around to or already have shifted to a 
northwest direction this morning. This will allow the colder air
to spill into the region and allow for the lake effect snow 
showers to fire up in the northeast snowbelt. Model soundings 
still support well aligned flow below the inversion today into 
tonight along with moderate instability. High pressure will 
begin to build into the local area Wednesday and with that will 
come drier air. This will bring a return to fair weather across 
the entire forecast area. Lake effect will linger during the 
morning hours in the northeast as flow shifts away from the 
Cold air advection spilling into the area will drop temperatures
a few degrees for Wednesday's high compared to today. Overnight
lows will be in the lower to middle 20s across the area.
A closed upper low moving out of the Mississippi Valley will lift 
north Wednesday Night and into the Ohio Valley by Thursday Night. 
This feature will bring confluent flow aloft supporting 
precipitation. Meanwhile a surface low off the east coast will 
deepen resulting in a strengthening of a warm air advection in the 
low level jet. This will have the effect of bringing some moisture 
into the area, though most will be captured east of the 
Appalachians. The overrunning will begin during the overnight with 
precip reaching the ground around dawn. At the onset, there is the 
potential for rain/snow/sleet/or freezing rain. Lingering drier mid 
levels will likely cut off saturation in the DGZ and ice crystal 
growth zone, so that most clouds in our area will just contain 
supercooled water droplets. This would result in precipitation being 
a very light rain or drizzle for areas south of US 30. Surface 
temperatures will be very close to the freezing mark, and any 
lingering drizzle or light rain showers could transition into 
freezing rain/drizzle, or sleet/snow if saturation occurs in the ice 
crystal growth zone. Any precipitation is expected to quickly turn 
over to all rain as warm air advection in the low levels increases. 
The bulk of the accumulative precipitation looks to exit the region 
Friday morning with some potential lake effect snow showers 
developing. Given that surface temperatures will be above freezing 
when/if the snow falls, and that the overall expected intensity of 
any snow showers should be light, any accumulations shouldn't amount 
to much.
Lake effect showers will be ongoing into Friday night. The pattern 
becomes more zonal on Saturday which will bring the potential for 
some smaller resolution/quick hitting and weaker upper level 
disturbances. These could bring light snow showers to the area that 
are difficult to time. Again with temperatures above freezing for 
most of the daytime hours and a modest diurnal swing don't 
anticipate accumulating snow.
.AVIATION /18Z Tuesday THROUGH Sunday/...
Conditions will slowly improve this afternoon into this evening.
Mainly MVFR ceilings and visibilities were being observed
areawide with occasional light snow showers being seen over the
eastern portions of the area. Most areas will have VFR ceilings
by later this evening and overnight. Winds will continue to be
northwest around 10 knots.
OUTLOOK...Non-VFR through Wednesday northeast Ohio and 
northwest Pennsylvania. Non-VFR possible again Thursday night 
and Friday.
Hoisted a small craft advisory as onshore winds are expected to 
increase to 15 to 25 knots this afternoon. An area of low pressure 
off the eastern seaboard will deepen today increasing the pressure 
gradient over the area with high pressure over the central plains. 
This will support a steady northwest wind into Wednesday. Wave 
heights with onshore flow will build to around 8 feet. Winds will 
relax gradually through Wednesday as surface high pressure moves 
east and over the lower lakes through Thursday. The pattern becomes 
more active late week as another east coast low develops. This 
feature will once again bring small craft conditions mainly on 
MARINE...Small Craft Advisory until 11 AM EST Wednesday for LEZ147>149.
     Small Craft Advisory until 7 AM EST Wednesday for LEZ145-146.
NEAR TERM...Griffin/Lombardy
SHORT TERM...Jamison
LONG TERM...Jamison