Area Forecast Discussion
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FXUS62 KRAH 272020
Area Forecast Discussion
National Weather Service Raleigh NC
320 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 300 PM Monday...
An area of showers extending from the SC Upstate through the Atlanta
metro area is associated with a low amplitude trough crossing the
Deep South. This feature should continue to move in an east-
southeast fashion and weaken with time. The best lift associated
with this system will remain south of our region. While we will see
an increase in the mid-high level cloudiness associated with this
feature, the bulk of the evening hours should remain dry across
central NC. Eventually, increasing sly flow a few thousand feet
above the surface will result in isentropic upglide of sufficient
strength to trigger a few showers overnight, primarily along and
west of highway 1. What showers that do occur will be spotty and
brief in duration with amounts ranging from a trace to no more than
a couple of hundredths.
The considerable cloudiness tonight will act as a blanket and keep
us several degrees warmer than last night. Overnight temperatures
upper 40s to around 50 nw to the low-mid 50s 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 /18Z MONDAY THROUGH SATURDAY/...
As of 1250 PM Monday...
There is a high likelihood of VFR conditions across central NC
through 03Z Tuesday. An area of high pressure at the surface will be
positioned offshore by tonight while an area of low pressure drifts
slowly west. The resultant circulation around these two weather
systems will yield a sly flow. This flow will lead to moisture
increasing across the region overnight into Tuesday. This will
increase the chance for low end VFR/MVFR ceilings, primarily across
the western counties including the Triad terminals after 06Z
Tuesday. In addition, there is a chance for a few showers overnight
into the first half of Tuesday morning.
An unsettled weather pattern across central NC through Wednesday
night will lead to an increased risk for sub VFR conditions.
Additionally, a tightening pressure gradient will lead to windy
conditions Wednesday with gusts 30-40kts highly probable. Prior to
that, there is a chance for low level wind shear conditions
overnight Tuesday night, more so speed shear rather than directional
The approach and passage of a cold front late Wednesday and
Wednesday night will also increase the risk for a few thunderstorms.
At this time, VFR parameters appear highly probable Thursday through