Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Cleveland Ohio
454 am EDT Monday Apr 27 2015
a trough will move south across the eastern Great Lakes today.
Weak high pressure will be overhead Tuesday and Wednesday. A cold
front is expected for Thursday.
Near term /until 6 PM this evening/...
trough/vorticity lobe across Lake Huron as seen on latest water vapor
img will pivot south today across the eastern Great Lakes. Low/middle
clouds associated with this trough have made steady progress
southward overnight and expect that entire area will be mostly
cloudy by middle/late morning. Limited moisture with the trough...but
enough to bring isolated/scattered showers to areas roughly east
of I-71. Precipitation will first reach northwest PA...but late enough that the
expectation is for it to be all rain...no early morning mix. Quantitative precipitation forecast
is light...a tenth of an inch or less of rain today. The best
precipitation chances will be this morning...with a few of the showers
lingering across Stark/Mahoning into the early afternoon. Will get
some breaks in the overcast across the west by this afternoon. We
maintain our light northerly flow with this trough passage.
Temperatures will continue to run below normal today...with 40s
far east to lower/possibly middle 50s across the I-75 corridor.
Short term /6 PM this evening through Thursday night/...
the region will be under the influence of brief ridging
Tuesday/Wednesday. Fair weather and temperatures closer to normal
can be expected. With northerly flow continuing...warmest
locations will be inland. Remaining cloud cover this evening is
expected to scatter out. Partly cloudy Tuesday/Wednesday.
Confidence in forecast for Thursday low. Interaction of jet energy
developing a trough/possibly closed low across the Great Lakes
Wednesday and the southern branch of the jet which takes a
shortwave across the Gulf Coast states/Tennessee Valley to the East Coast
varies. Op GFS appears to remain the outlier and have sided more
toward the European model (ecmwf) and GFS ens which are not as deep with the upper
low. So eventually will see some light showers with the upper
low/trough across the Ohio Valley...at this point Thursday. Kept
probability of precipitation at 30 or 40 percent at the highest for now. Temperatures
Long term /Friday through Sunday/...
not a lot of confidence in the extended portion of the forecast
although there will likely not be much significant weather for the
forecast area. The models are struggling with a couple of closed
lows and have been inconsistent. The GFS seems to be the only model
that deepens the northern closed low...and digs it farther south
than the other models by Wednesday night. This eventually leads to
an East Coast low that is deeper and rides farther up the coast than
the other models Thursday into Friday. We would likely be on
the west side of any upper trough or upper low and odds would favor
drier weather by Friday. A weakening cold front is prognosticated to
approach on Saturday.
The good news is that by late in the week we should flush out the
remaining chilly air and bring in a warmer southwest flow. Will
continue with a forecast of highs in the 60s to lower 70s Friday and
Saturday. More uncertainty by Sunday as the weakening front may
become stationary nearby. Some of the models show a wave on the
front. Will have a small chance of showers by Sunday as per the
current forecast and will keep it warm on Sunday.
Aviation /06z Monday through Friday/...
the trough over Ontario will drop south across the area this
morning. Patchy showers and MVFR ceilings are most likely across
northeast Ohio and northwest PA morning and midday. Northwest Ohio
will likely stay dry and VFR. Ceilings should improve to VFR by
middle/late afternoon. VFR tonight.
Outlook...non VFR possible on Thursday.
several troughs of low pressure will drop across the lake from the
north through middle week. The gradient should be rather weak but with
the passage of each trough the wind could pick up for a few hours
and the northwest to north wind direction will maximize the
wind/waves on the South Shore. Not expecting enough wind or waves
for a Small Craft Advisory though. Not much confidence in the
forecast toward the end of the week but the flow should begin to
back toward the west and southwest by Friday and the weekend.