Scientific Forecaster Discussion
fxus61 kpbz 171533
Area forecast discussion
National Weather Service Pittsburgh PA
1033 am EST sun Nov 17 2019
cool and mostly dry weather will prevail over the next several days.
The next chance for a widespread rainfall will be late Thursday into
Friday. In the meantime, a chilly November continues.
Near term /through tonight/...
Southerly flow in the low to mid-levels ahead of an approaching
shortwave will result in a temperature rise, compared to yesterday,
across the region. However, with the elongated trough across the
eastern conus, the temperature will stay below the climatological
average. Areas east of the ridges may remain under a cloud deck as
low- level moisture, near 2kft from a low pressure system off the
Carolina coast moves north. One can note the barrier the ridges
establish on the cloud deck on visible satellite.
Clouds will begin to increase from the west as the shortwave trough
approaches the Ohio River valley later today.
Short term /Monday through Tuesday night/...
the first of a series of shortwave troughs will swing through the
region on Monday. However, most upper-level divergence will be
displaced away from the forecast area. So this lack of upper-support
in conjunction with little moisture will result in only a very
minimal chance of precipitation through much of Monday.
Tuesday will be similar to Monday in terms of temperature, where
highs should reach the 40s. However, the next two shortwave troughs
will be better positioned to generate precipitation for the forecast
area. Still, moisture can be described as meager-at-best. Only very
light precip is expected, with most coming in the form of of rain.
Higher elevations (>2000ft) and locales north of I-80 may see a mix
of rain/snow, with potential changeover to all snow by late Tuesday
night. Little to no accumulation is expected.
Long term /Wednesday through Saturday/...
- a slow warming trend, Thursday will be the warmest day
- best chance of widespread rainfall comes Thursday - Friday
- no snow accumulation forecast this week
Any precipitation early Wednesday morning should quickly dissipate
by mid-morning as shortwave ridging builds across the area in wake of
the departing trough. Cool northwest flow off the Great Lakes may
keep cloud cover around for the day, before eroding in the evening
with a backing wind.
Models are coming to better agreement with that of a shortwave in
the northern stream phasing with an impulse ejecting northeastward
from the southern rockies toward the Great Lakes. Strong southerly
flow / warm advection ahead of this feature will result in Thursday
being the warmest day of the forecast period. The temperature should
climb to near or above 50 for most locations.
Most upper-support will be north of the forecast area, but warm
moist air in conjunction with convergence along an advancing cold
front will result in precipitation overspreading the region by late
Thursday evening. Temperature profile looks too warm for any snow for
most areas, but usual spots of high elevations and north of I-80
could see a mix before the precip ends.
Cool, dry weather will then follow for the subsequent 48 hours or so
until the approach of the next low pressure system.
Aviation /15z Sunday through Thursday/...
high confidence forecast. VFR is expected through the taf period.
Stratocu with southeast wind should stay east of duj and lbe.
Southeast wind around 10 kts is forecast.
sub VFR restrictions are likely Monday night into Tuesday with the
passage of a low pressure system especially at fkl and duj.