Scientific Forecaster Discussion
fxus62 krah 180211
Area forecast discussion
National Weather Service Raleigh NC
1011 PM EDT Tue Sep 17 2019
a backdoor cold front will move south through central NC this
evening. Canadian high pressure will build down the eastern Seaboard
tonight through Friday, bringing much cooler and less humid
Near term /tonight/...
as of 1010 PM Tuesday...
The last of the isolated showers associated with a cold front coming
southward through the County Warning Area are exiting the County Warning Area to the south. Winds
have gone northeasterly everywhere but that being said the full
airmass change is still several hours away as lower 60s and upper
50s dewpoints are still back across the Tidewater Virginia area and will
filter in from the northeast overnight. No further showers are
expected overnight so have reduced precipitation chances to near nil
overnight although some very light returns may skim our western
border but of very little to no consequence. Overnight lows will
vary widely from upper 50s to low 60s in the northeast to mid 60s
across the southwest. The more likely bust scenario in this case is
that the temperatures may not come in quite as quickly in the
northeast as forecast so it is very possible that they do not drop
into the upper 50s.
Short term /Wednesday through Wednesday night/...
as of 355 PM Tuesday...
Surface high pressure building south down the eastern Seaboard will
advect cp air into the Carolinas through the period. Precipitable waters are
forecast to fall to ~ 0.50" Wednesday night with equally impressive
low sfc dewpoints, that will be aided by daytime mixing, falling
into the upper 40s and lower 50s. Northeasterly wind gusts of 15 to 20 mph
will provide a refreshing breeze through the afternoon as afternoon
temps top right around the 30 year avg. Highs ranging from mid to
upper 70s north to lower 80s south.
Slight mixing Wednesday night will prevent min temps from bottoming
out completely. But still expect a few upper 40s possible in the
typically cooler spots. Otherwise, lows in the lower 50s.
Long term /Thursday through Tuesday/...
as of 325 PM Tuesday...
High pressure will remain entrenched across central NC through the
period, allowing cooler and drier conditions to persist through the
remainder of the work-week. The upper ridge will begin to build back
east on Friday, allowing for a slow warming trend as we progress
through the weekend into early next week. Afternoon high
temperatures will remain in the upper 70s Thursday, rising to near
80 Friday, with an additional few degrees added on each afternoon
next weekend. Overnight lows will dip into the 50s, with a few upper-
40 degree readings possible in the usual cold spots. Chances of rain
will remain near zero for the majority of the period, with a slight
chance of showers returning to the forecast by the middle of next
week as a series of weak cold fronts approach from the northwest.
Aviation /00z Wednesday through Sunday/...
as of 745 PM Tuesday...
Brief MVFR conditions are possible at rdu and rwi through 02z near
and just behind a cluster of showers pushing southward through these
areas. These showers are ahead of a southward-moving backdoor front
now pushing through NC. Later tonight, between 05z and 11z, a period
of MVFR cigs and showers is possible at int/gso as the front and a
moist easterly flow settle over the west Piedmont. Otherwise, central
NC will see a clearing trend from NE to SW late tonight through Wed
morning as high pressure builds in from the NE behind the front. The
entire area will see a trend toward gusty winds from the NE starting
near or soon after sunrise, with sustained winds 8-12 kts gusting to
15-20 kts, lasting through Wed under mostly clear skies.
Looking beyond 00z Thu, VFR conditions will dominate through the
weekend under high pressure, although shallow ground fog near bodies
of water is possible early Fri morning and again Sun morning. -Gih
Synopsis...weather forecast office rah