Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC
FXUS62 KRAH 200523
Area Forecast Discussion
National Weather Service Raleigh NC
1225 AM EST Mon Feb 20 2017
High pressure will build into the region tonight, then move offshore
on Tuesday. A low pressure system will cross to our south on
.NEAR TERM /THROUGH TONIGHT/...
As of 1059 PM Sunday...
Clear skies at sunset noted from the Mississippi Valley eastward to
well off in the western Atlantic. The light NW flow over central NC
continued to diminish. Nearly calm conditions are expected the
rest of the overnight. Temperatures late evening were around 50 NW
ranging to 60 SE. Clear skies expected overnight with lows very
mild, mostly in the lower to mid 40s, except for some upper 30s
in the normally colder locations of the northern Piedmont.
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
As of 150 PM Sunday...
The center of a high pressure ridge will drift across southern
Quebec during this time frame while nosing southward through central
NC. Dry and deeply stable air will persist through Monday, yielding
mostly sunny skies, with just a few high clouds within fast
northwesterly upper flow. Thicknesses will start out a bit lower
than in the last couple of mornings, particularly over the NE
sections of the forecast area, beneath the heart of the ridge axis.
But values will still be well above normal, supporting highs from
the upper 60s NE to the mid 70s in the far southern CWA. As the
ridge axis shifts to our east Mon night, resulting in a
southeasterly and southerly low level flow into central NC, low
level moisture will steadily advect into the area, with increasing
moist upglide focused around 290K across the western CWA overnight.
Will have increasing clouds Mon night, especially in the west, with
the relatively cooler ridge lingering in the NE CWA. Expect lows
from the upper 30s NE ranging to the mid to perhaps upper 40s in the
western CWA. -GIH
.LONG TERM /TUESDAY THROUGH SUNDAY/...
As of 254 PM Sunday...
Tuesday will begin with the upper level ridge axis right overhead
and a surface low pressure system over New England. Clouds will
increase throughout the day ahead of a frontal system over the
Mississippi Valley. Highs in the mid to upper 60s. As the surface
high moves offshore and the front gets closer, warm air advection
will begin and temperatures on Wednesday will soar into the mid 70s.
As the front moves through there will be some chance for rain
showers but not a soaker of a day by any means.
Despite the front moving through it eventually washes out and the
high pressure that was over new England dips southward off of the
Carolina Coast and thus no real change in airmass occurs as return
flow keeps warm air moving into central NC. This will keep
temperatures in the mid to upper 70s for Thursday as frontogenesis
begins to occur across the Appalachians as a low pressure system
develops over the plains and pushes eastward. This will give slight
chances for rain across the north on Thursday but again with meager
moisture content as a warm front organizes and pulls away to the
north as the parent low moves front the Plains northeastward towards
the Great Lakes. The timing of the evolution of this system is in a
big of question with the GFS showing a quicker progression of the
advancing cold front and the ECMWF still a little slower but faster
than yesterday. As a result the best chance for some significant
rainfall and perhaps a thunderstorm or two will begin on Friday and
progress through Saturday but clearing out for Sunday. Highs in the
70s through Saturday before easing back into the mid 60s for Sunday.
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
As of 1225 AM Monday...
There is a high likelihood of VFR conditions across central NC
through 06Z Tuesday. An area of high pressure at the surface will
build in from the north today. This system will maintain mostly
clear skies and light surface winds through tonight.
With high pressure to our north-northeast later tonight, a low level
ely flow will develop. This flow will transport moisture off the
Atlantic, and into the Piedmont. As the moisture meets the upslope
region of the foothills and the higher terrain of western NC, areas
of stratus will develop. This stratus layer may spread into the
western Piedmont after 06Z Tuesday, increasing the risk for sub VFR
ceilings. The risk for sub VFR ceilings appear higher late Tues day
night into Wednesday morning.
There will be a chance for sub VFR ceilings Wednesday through Friday
across central NC as a moderately moist air mass and an unsettled
weather pattern is expected.