Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 12/12/21
AREA FORECAST DISCUSSION
National Weather Service Raleigh NC
845 PM EST Sat Dec 11 2021
.SYNOPSIS...
A cold front will cross the area this evening. High pressure will
build into the region on Sunday and persist through mid week, with a
warming trend.
&&
.NEAR TERM /TONIGHT/...
As of 845 PM Saturday...
A line of sub-severe convection has advanced to the Interstate 95
corridor and continues to move east. There were a couple of reports
of trees down shortly after sunset, but nothing like the severe
weather that happened farther west in the last 24 hours. Some
stronger showers dropped a quarter to three-quarters of an inch of
rain, but in general rainfall has been relatively light. To the west
of the line of convection, light rainfall extends back to the actual
cold front which is currently just west of the forecast area.
Temperatures are still in the 60s (above mid-December normal highs)
and winds have a southerly component, but this will change during
the rest of the evening. Considering how isolated lightning has been
along the line of convection, have removed thunder from the forecast
at all locations for the rest of the night. Showers should be coming
to an end in the Triad around midnight with rain lingering in the
east through much of the night. Additional rainfall will be one-
quarter to one-half inch - nothing that will break the drought, but
every little bit is helpful right now. Overnight lows will range
from the mid-30s in the northwest to the mid-40s in the southeast.
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
As of 218 PM Saturday...
The mid-level trough axis will be exiting our area by 12Z Sunday,
then look for subsidence and clearing skies in it`s wake for the
rest of Sunday, and while high pressure builds in from the west. As
the high builds in during the morning and afternoon, the tightened p-
grad will result in N-NE winds with gusts aoa 15kt. But by evening,
the high will be settled right over central NC, so look for the p-
grad and winds to relax quickly. Overall, a nice weather day with
plenty of sunshine during the day and clear at night, but with
seasonably chilly temps with highs Sunday in the low to middle 50s.
Lows Sunday night 25 to 30, thanks to clear skies, calm winds, and
radiational cooling.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
As of 218 PM Saturday...
Dry and above normal through Friday, with a potential cold front and
showers late in the period.
High pressure will be in place across central NC on Monday. High
temperatures will be about 5 degrees warmer than Sunday in the upper
50s to lower 60s under sunshine. With clear skies and light winds
expected again in the evening, good radiational cooling will once
again favor overnight lows slightly below normal in the upper 20s to
lower 30s.
There is very little change in the extended period from Tuesday
through Friday, with a mid-level anomalous ridge of high pressure
over the northern Gulf of Mexico that slowly moves into the
southeast US by the end of the week. With the exception of a weak
back door cold front on Wednesday from high pressure settling into
the Northeast US lowering our highs into the upper 50s to middle
60s, temperatures will largely follow an upward trajectory, rising
into the upper 60s to low/mid 70s Thursday and Friday. This is about
15-20 degrees above our seasonal normals for the middle of December.
The latest model guidance has slowed the approach of a cold front
into central NC until Saturday night to early Sunday, as high
pressure over the Midwest settles into the Ohio Valley. Ensemble
guidance from the EPS/GEFS keep any rain chances largely in the
Saturday night to Sunday timeframe but there remains high spread in
the individual members. The pattern at mid-levels features a trough
over the Great Lakes Saturday tracking into the Northeast US and Mid-
Atlantic, with height falls over central NC Saturday night. At the
same time, another potential cutoff mid-level system may form over
Baja California. How the pattern evolves will likely change between
now and next weekend so have only introduced slight chances of rain
Saturday. Expect a downward trend in temperatures by the end of the
period as a result.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
As of 655 PM Saturday...
The primary aviation concern is now through midnight, as a line of
showers and isolated storms moves through central NC, producing a
period of MVFR cigs and MVFR to IFR vsbys as they pass through.
Strong surface gusts from the SW as high as 35-50 mph are occurring
with, and for a few hours after, the arrival of rain, and this will
produce some mechanical turbulence and difficulty with aircraft
handling this evening. A shift of winds to be from the NW will occur
W to E with passage of a cold front between 01z and 06z, followed by
a gradual diminishing of gusts behind the front later tonight in
tandem with rising cigs to VFR and, toward daybreak, clearing skies
as high pressure builds in. From mid Sun morning on, clear skies and
winds from the NW or N at 7-12 kts are expected, decreasing further
in the afternoon.
Looking beyond 00z Mon, VFR conditions should dominate through Thu
as high pressure builds over the region, although there is a chance
for sub-VFR fog early Thu morning. -GIH
&&
.CLIMATE...
Record high min temperature and record high temperatures on
December 11th...
RDU 57 (2008)74 (2007)
GSO 54 (2008)78 (2007)
FAY 60 (1972)80 (2007)
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Hartfield
NEAR TERM...Green
SHORT TERM...np
LONG TERM...Kren
AVIATION...Hartfield