Scientific Forecaster Discussion
fxus62 krah 141132
Area forecast discussion
National Weather Service Raleigh NC
630 am EST Sat Dec 14 2019
low pressure will move up the mid-Atlantic coast today, with high
pressure briefly over the region Sunday and Monday. Another cold
front will sweep across the area Monday night and Tuesday, with the
rest of the week expected to be dry.
Near term /through tonight/...
as of 630 am Saturday...
The back edge of rainfall is quickly approaching the western edge of
the forecast area, with showers expected to come to an end by early
afternoon. Thunderstorms have expanded in coverage off the South
Carolina shore, but no thunderstorms are expected over North
Carolina at this point. Some partial clearing will occur through the
afternoon hours, but more definitive clearing does not appear to be
likely until after dark, especially after midnight. Winds will gust
out of the southwest up to 25 mph during the afternoon, and the
southerly flow along with partial sunshine should help to raise
highs anywhere from 5 to 15 degrees warmer than friday's values.
Overnight lows will be rather uniform in the upper 30s.
Short term /Sunday through Sunday night/...
as of 220 am Saturday...
Weak surface high pressure will build across the southeastern United
States with weak mid-level ridging developing across the East Coast.
Sunday will be a sunny day with clouds beginning to develop Sunday
night in advance of the next approaching system. Nearly calm winds
will also allow for some patchy fog Sunday night as well.
Temperatures Sunday and Sunday night will be within a degree or two
of values from Saturday.
Long term /Monday through Friday/...
as of 233 am Saturday...
Broad zonal flow across the mid Atlantic on Monday will gradually
transition and take on a more southwesterly component as a deepening
trough moves through the Ohio Valley. At the surface, high pressure
will retreat off the coast and pre-frontal warming should yield
afternoon highs in the low to mid 60s despite increasing clouds. By
Monday evening, the cold front is expected to enter the western
Piedmont with showers gradually overspreading the area by daybreak
Tuesday. Very good run to run agreement from the deterministic
solutions with respect to timing of the frontal passage, ensembles
have maintained good temporal consistency as well. All signs point
to widespread showers early Tuesday, gradually tapering off from
west to east Tuesday afternoon and evening. Pops were adjusted
slightly upward during the early part of Tuesday, then rapidly
trimmed Tuesday night Onward as high pressure settles over the area
Wednesday through Friday. Cooler temperature are also forecast from
Wednesday Onward with highs several degrees below normal.
Aviation /11z Saturday through Wednesday/...
as of 630 am Saturday...
24 hour taf period: while kint/kgso/kfay have reported VFR ceilings
as of 11z, am very suspicious of these observations considering all
surrounding obs remain under IFR/LIFR cigs. Have continued with low
cigs initially at all sites, with ceilings slowly rising to VFR by
early afternoon. Rain will also have moved east of the area by that
time. Although winds are currently light and variable, they will
eventually come around to the southwest with gusts up to 20-25 kt.
Looking ahead: some patchy fog will be possible in the pre-dawn
hours both Sunday and Monday mornings, but otherwise VFR conditions
should prevail Sunday and Monday. Another frontal system will move
through Monday night through Tuesday night, resulting in a return to
sub-VFR aviation conditions and rain.