Area Forecast Discussion
Issued by NWS
FXUS61 KPBZ 111936
Area Forecast Discussion
National Weather Service Pittsburgh PA
236 PM EST Wed Jan 11 2017
Several periods of rain will continue through the week until more
seasonable temperatures return by Friday. A wintry mix is
expected over the weekend.
.NEAR TERM /THROUGH TONIGHT/...
A strengthening shortwave, combining with increasing moisture
from the Tennessee Valley, will bring rain back into the region
later this afternoon/early evening. The quick progression of the
shortwave will end rain from the south to the north early tonight.
Temperatures will be well above normal.
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
The next cold front will bring more rain on Thursday mainly
during the afternoon and evening hours. Some parts of the region
may receive more rainfall due to the lack in eastward progression
of the front until the trough axis helps push the front out of the
area late Thursday. The boundary is expected to sag south of the
forecast area on Friday.
High pressure will build over the eastern Great Lakes behind the
front keeping the area dry on Friday. This feature will play a
crucial role in determining the weather type for the weekend. As
of now, confidence is increasing for the existence of a wintry
mix to occur on Saturday over much of the forecast area as
overriding warm air encroaches with the northward shift of the
aforementioned boundary. There is, however, uncertainty in the
northward extent of the boundary and therefore used the superblend
to maintain chance to likely PoPs. Sufficient cold air damming
should help result in freezing rain to occur, with the largest ice
accumulation amounts progged over Garrett and Tucker Counties.
.LONG TERM /Saturday NIGHT THROUGH WEDNESDAY/...
The weekend front will linger across southern portions of the
forecast area and may continue to cause a wintry mix, and with
uncertainty as to exactly where the front will be, have kept
likely pops generally contained to locations well south of
Pittsburgh on Sunday. GFS and ECMWF diverge in model solutions for
Sunday night and Monday with a system in the Plains, and have made
minimal changes to this portion of the forecast. Temperatures
should be near or slightly above normal.
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
VFR will deteriorate to mvfr with areas of IFR in rain showers
overnight as a frontal boundary pushes north. Low level wind shear
also expected as southwest low level jet over 50 KTs crosses
region. Some improvement across the far south Thursday morning,
otherwise continued IFR as cold front crosses Thursday afternoon.
Periodic restrictions in a possible wintry mix can be expected
for the weekend, especially across southern ports.