Area Forecast Discussion
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FXUS62 KRAH 280158
Area Forecast Discussion
National Weather Service Raleigh NC
858 PM EST Mon Feb 27 2017
High pressure will push further offshore through this evening,
followed by a warm front lifting through the area tonight. A mild
flow from the southwest will persist Tuesday through Wednesday,
ahead of a cold front that will cross the area Wednesday night.
.NEAR TERM /THROUGH TONIGHT/...
As of 900 PM Monday...
The 00z GSO sounding hints at a key shift in the forecast this
evening and that is extremely dry conditions below 700 mb all the
way to the surface. As a result, not much moistening of the
atmosphere has occurred and even though isentropic lift will pick up
during the overnight hours, having a hard time believing that we
will get any precipitation west of US Highway 1. Currently the warm
front can be seen in the observations near Columbia SC with an
increase in dewpoints of around 10 degrees. Earlier runs of the NAM,
WRF and others depicted precipitation forming in the western
Piedmont and moving east during the early morning hours as this
front pushes northward. Instead, would now favor the HRRR and RAP
solutions which show precipitation mainly in the southeastern
counties and after 6z and continuing to into the morning with the
bulk of the precipitation occurring east of I-95. Expect low temps
in the mid 40s in the Triad to low 50s in the southeast.
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
As of 320 PM Monday...
Tuesday...the isentropic lift will decrease shortly after daybreak
Tuesday which should lead to a diminishing of the shower coverage.
After 14z, the greatest threat for a shower or two will be roughly
along and east of I-95. An increasingly moist and conditionally
unstable air mass coupled with the approach of a perturbation
lifting east-ne from the TN Valley into the mid-Atlantic Tuesday
afternoon will trigger a few additional showers and possibly a
thunderstorm. SInce forcing fairly weak, do not expect coverage to
be any worse than isolated or scattered.
A steady sly flow along with periods of sun should boost afternoon
temperatures into the low-mid 70s with upper 70s highly probable
across the far southeast.
Tuesday night...the mild weather will continue as a low level jet
will strengthen overhead in response to an amplifying s/w lifting to
our northwest. The variably cloudy skies and steady sly flow will
maintain overnight temperatures in the 60-65 degree range, closer to
normal daytime highs for early-mid March.
While a shower or two may occur to the north-nw of Raleigh and the
Triad, the bulk of central NC will remain dry as forcing expected to
be weak at best.
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
As of 235 PM Monday...
Wednesday and Wednesday night: As the low pressure system over the
Midwest moves eastward on Wednesday, the parent low will move over
the Great Lakes region while the upper level trough/sfc cold front
extending from the Great Lakes southwest through the ARKLATEX
progress east toward the Carolinas. Over Central NC, continued warm
southerly flow will persist through the day Wednesday as cloud cover
and chances for convection increase from the west. Highs will range
from mid 70s NW to low 80s south. South-southwesterly winds will be
quite strong on Wednesday, sustained 15-20 kts with gusts to around
30 kts, strongest just before sunset and then again with the front.
Latest model solutions continue to suggest the best chances for
convection (shower and possible strong thunderstorms) will move into
the west late Wednesday evening, quickly moving eastward through
Central NC by early Thursday morning. Despite the poor diurnal
timing of the axis of convection the high (uni-directional) shear
and low (500-1000 J/Kg) CAPE will result in the slight chance for
thunderstorms to produce some damaging winds as they move through
the region. The likelihood decreases with time as the showers
progress through the area.
Wednesday night, winds will become more northwesterly, cold air
advection will commence and skies will begin to clear. As a result
of current fropa timing, low temperatures will range from mid 40s NW
to mid 50s SE. Winds will continue to be breezy overnight (10-15 kts
with gusts to around 20 kts).
Thursday through Monday: This period is expected to remain dry.
Highs Thursday and Friday will still be in the upper 50s to mid 60s,
lows Thursday night in the mid 30s. A reinforcing dry cold front
will push through late in the week with the coldest temperatures
(mid 20s to around 30 degrees) expected Friday night/Saturday
morning as the surface high moves overhead. Highs Saturday will be
the lowest of the period, mid to upper 50s. Expect moderating
temperatures once again for the remainder of the weekend and into
next week as yet another low pressure system develops out west and
the flow over the Carolinas becomes increasingly southerly.
.AVIATION /00Z Tuesday through Saturday/...
As of 710 PM Monday...
VFR conditions are likely to hold for a few more hours, but a trend
toward IFR at INT/GSO and MVFR elsewhere is expected later tonight,
mainly after 08z. Mid and high cloudiness over the area, caused by a
weak mid level disturbance, will be exiting slowly to the east
through tonight, however lower level moisture will stream in from
the SW later tonight, generating a trend to IFR cigs at INT/GSO and
MVFR cigs at RDU/FAY/RWI after 08z, lasting through around 13z, at
which time cigs will rise to MVFR at INT/GSO and VFR elsewhere
through mid/late morning. Winds will increase during the morning
from the SW at 8-12 kts with occasional gusts to 15-20 kts, lasting
through the afternoon. A few showers and isolated storms are
possible late Tue afternoon into the evening, but coverage and
confidence are too low to mention at this time.
Looking beyond 00z Wed, a trend back down to sub-VFR cigs is
expected after 06z early Wed morning with a steady breeze from the
SW overnight. Low level wind shear (unidirectional) is possible late
Tue night through daybreak Wed. Cigs will lift slowly toward VFR
through Wed, with a good chance of showers and storms -- some of
which could be very strong -- very late in the afternoon through the
evening and nighttime hours, ahead of a cold front. Strong and gusty
winds from the SW are likely Wed into Wed night, sustained around 20-
25 kts with gusts of 30-40 kts possible. Cold front passage Wed
night will shift winds around to NW with clearing skies, and VFR
conditions will dominate Thu through Sat. -GIH