Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Cleveland Ohio
1159 PM EST Sat Jan 31 2015
strong low pressure system will track across Ohio late Sunday into
Monday morning. The low will move off the middle Atlantic coast late
Monday as a dome of Arctic air spreads southeast across the forecast
Near term /until 6 am Sunday morning/...
Adjustments made to the winter storm forecast...mostly across the
southern half of the forecast area...trending towards a wintry mix
with less snow accumulation. Winter storm warnings remain in
effect for all areas.
Winter storm continues to take shape over the plains with
precipitation starting to reach the ground in SW Ohio.
Temperatures are already in the low 30s across central Ohio with
dewpoints across Indiana near 30. 00z NAM is now taking the
surface low track across central Ohio towards Youngstown by 06z
Monday. The new 00z GFS remains slightly to the south but is
plenty warm with 1000-850mb thicknesses up to 1305m as far north
as mfd-yng line which would support a transition to rain. These
more northern tracks continue to make sense given how much the
trough deepens to our west.
This leaves US with a difficult forecast in terms of low level
thicknesses/temperatures but have made adjustments to the warmer
scenario. The boundary layer does try to warm to near or above
freezing in our southern counties during the afternoon and evening
tomorrow. We could see a break in the precipitation in the south
which could allow temperatures to sneak up an extra couple
degrees. Expect the far southern counties will transition over to
rain for a period of time but hard to say exactly how far north
the wet snow/sleet line pushes. It could extend all the way to the
Cleveland metropolitan area. Raised highs on Sunday a few degrees but
some cooling due to melting is possible as precipitation intensity
increases. Lowered accumulations in the far south to 4 to 6 inches
of snow...tapering up to still near 10 inches in the far
north...with potentially up to a foot towards Toledo. The greater
forecast uncertainty is will we see freezing rain/icing or just
rain with less impact. We will look to high resolution models and
new guidance overnight to try to get a better handle on the storm
evolution for tomorrow. Adjustments to the forecast remain
Original discussion...temperature continue to rise as warm front
moves into western Ohio. Early evening should be pleasant with
sunshine and temperatures near 30....but that will not last long. All 3
models in good agreement moving Colorado low into southeastern Missouri by
daybreak Sunday. Think snow will develop across Northwest Ohio toward
midnight local and spread into northwest PA by 12z Sunday. Think
accumulations by Sunday morning will be on the light side with 1-2
inches across Northwest Ohio and an inch or less in the east.
Short term /6 am Sunday morning through Tuesday night/...
models continue to track the low to the Ohio River by Sunday evening
and then across southern Ohio Sunday night. The new GFS tracks the
low just south of Columbus Ohio while the NAM track continues to be
further south. GFS and European model (ecmwf) very similar so leaned toward a
European model (ecmwf)/GFS blend. Track of the 850mb low is further north than ydy
snow now the band of the heaviest snow a little further north...from
Northwest Ohio across Northern Ohio into northwest PA. Upwards of a foot of snow
is possible across the northern tier by Monday afternoon. A little
harder to determine for the southern counties. If GFS track holds
true could see some warm overrunning in the south which could
produce a short period of sleet or freezing rain south of a Marion
to Youngstown line. So snowfall southern counties may be closer to 8
inches. However the precise track of the low and the location for
the heaviest snow will likely continue to wobble over the next 24
Think accumulating snow will end from the west Monday morning.
However with a north to northeast flow off the lake and 850mb temperatures
plunging to -15c Monday afternoon...think there will be scattered
snow showers through early afternoon.
Arctic air will spill over the area Monday. With strong gusty winds
and single digit temperatures...Monday morning could see wind chills of -5
to -10 degrees. And if skies can clear Monday night actual lows
will be able to dip to below zero for a large portion of the area.
Long term /Wednesday through Saturday/...
the next cold front is expected to drop across the area Wednesday.
Some of the models spin up a weak wave on the front with a chance of
some enhanced precipitation but it is too early to try and pin down that
type of detail. Will have a "likely" pop for northeast Ohio and
northwest PA with a chance pop elsewhere. I doubt we would have
enough south southwest flow ahead of the front for mixed precipitation but
never say never. Will just forecast snow for the time being.
Colder again Wednesday night through Thursday night as a
reinforcing push of Arctic air crosses the area. The forecast
temperatures will be a little below guidance given the Arctic air
mass and the snow cover. Highs in the teens and lows down toward
zero or below.
The models vary late in the week on how fast the surface high will
move east. The European model (ecmwf) is faster bringing the next front across the
lower Great Lakes Saturday morning whereas the GFS is 12 hours
slower. The forecast will be a compromise with temperatures
recovering on Saturday into the 20s to near 30 and a small chance of
Aviation /06z Sunday through Thursday/...
the snow is spreading east somewhat slowly. Ceilings and
visibilities will drop to IFR from west to east by daybreak. A cold
front over lower Michigan will move into the area overnight and with
the low heading toward the Ohio Valley this will enhance the snow.
Will have to continue to monitor the track of the low. At this time
the GFS solution in tracking the low across central Ohio looks
great. This will cause some mix precipitation mainly at mfd...cak
and yng Sunday night. Confident some rain will occur at cak and yng
Sunday evening. At mfd it could be mainly freezing rain as
temperatures will be close to 32f. Very confident tol will remain
all snow. Moderately confident that fdy...cle and eri will remain
all snow...these will still need to be watched.
Outlook...non VFR conditions will persist late Sunday night into
Monday morning with snow and blowing snow...then conditions will
begin to improve. Non VFR possible again Tuesday night into
a light southwest flow on Lake Erie will persist for a while tonight
ahead of a cold front. Winds will transition to northeast fairly
quickly after the cold front drops south of the lake early Sunday
morning. A wave of deepening low pressure will track along the
front...across the Ohio Valley...Sunday evening. The increasing
pressure gradient will bring an increased northeast wind by late
Sunday and Sunday night. Northeast winds will approach gale force.
Tracks in the ice fields will not hold in the wind.
The wind should back to north northwest Monday and gradually
decrease as Arctic high pressure builds in. Winds will back to
southwest pretty quickly on Tuesday as another cold front
approaches. The next front will drop across the lake Wednesday and
more Arctic high pressure will build across the lakes late in the
Ohio...Winter Storm Warning from 4 am Sunday to noon EST Monday for
Winter Storm Warning until noon EST Monday for ohz003-006>010-
PA...Winter Storm Warning from 4 am Sunday to noon EST Monday for