Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC-- Highlight Changed Discussion --
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FXUS62 KRAH 231725
Area Forecast Discussion
National Weather Service Raleigh NC
125 PM EDT Mon May 23 2016
.SYNOPSIS...An upper level low will move across the area today,
before tracking along the East Coast and away from the region on
Tuesday. A strong upper level ridge will build over the Southeast
through the remainder of the week.
.NEAR TERM /through tonight/...
As of 1125 AM Monday...
Minor tweaks made to the near term forecast. Have adjusted PoPs up
over the northeast third of the CWA to account for patchy light rain
through mid day/early afternoon. Otherwise expect scattered showers
and a thunderstorm or two across the region from mid afternoon
Pesky upper level low has begun push to the east-northeast and on
track to exit our region by late in the day and well offshore
tonight. Spokes of vorticity will continue to pivot around this
feature with one axis currently working its way across our northern
counties. This feature will continue to progress south-southeast,
possibly triggering additional shower development across the
southern counties by mid afternoon.
While a thunderstorm possible, parameters are not quite there for
the potential for severe storms. The shear is too weak and
instability even weaker.
Temperatures this afternoon highly dependent upon extent of cloud
coverage and showers. Where clouds are thickest/more prominent and
potential for rain highest (ne third), temperatures in the 60s will
be the rule. Where peeks of sunshine occur, temperatures should warm
into the 70-75 degree range. Expect the warmest temperatures in the
far south and southwest where mixture of sun/clouds expected. -WSS
Height rise aloft and high pressure building in from the west will
rapidly diminish precip coverage this evening, while skies slowly
clear behind the departing upper trough. Lows in the low/mid 50s. -22
.SHORT TERM /Tuesday and Tuesday Night/...
As of 340 AM Monday...
While the center of the mid/upper-level low will be in the process
of lifting up the coast of the northern Middle Atlantic and
Northeast...a couple of low amplitude impulses are forecast to wrap,
in NW flow on the WSW periphery of the departing low, across eastern
VA/NC through early-mid afternoon Tue. Residually steep mid-level
lapse rates /6 to 6.5 C/KM/ over the NE Piedmont and Coastal Plain,
and diurnal heating into the lower 80s, will contribute to perhaps a
couple of hundred J/KG of MLCAPE there, where an isolated
shower/sprinkle (POP of only 10-15 %) may occur before following
strong height rises aloft and an associated subsidence inversion
overspread the region.
One more night in the 50s, to around 60 degrees, is expected in
continued height rises in NW flow aloft Tue night.
.LONG TERM /Wednesday through Sunday/...
As of 355 AM Monday...
Increasingly hot, but mainly dry.
Within a relatively highly amplified flow pattern consisting of a
western CONUS trough and eastern CONUS ridge, a couple of low
amplitude southern stream perturbations will migrate across the
Middle Atlantic late Wed-Fri. These perturbations will get trapped
and stretched in a deformation zone aloft between the center of a
couple of sub-tropical highs over Mexico and offshore the SE U.S
coast, and may contribute to the development of diurnal convection
across the Appalachians and/or along the sea breeze in coastal areas
during that time. While an associated shower or storm cannot
entirely be ruled out even over central NC, a lack of any more
appreciable focusing mechanism suggests that probability will be
low. Temperatures will climb into the upper 80s to around 90 degrees
mid-late week, with perhaps slightly cooler conditions owing to a
slightly onshore component to the low level flow, this weekend.
.AVIATION /18Z Monday through Saturday/...
-- Changed Discussion --As of 125 PM Monday...
Ceilings varying between MVFR across the northeast piedmont and the
coastal plain to low end VFR across the western and southern
piedmont will persist through sunset as energy rotating around an
upper level low over far northeast NC. As the atmosphere heats
up, scattered showers and isolated thunderstorms will blossom over
the region. The greatest coverage will occur between 20Z-00Z.
After 00Z, shower coverage will decrease. Later tonight, as
the low pulls farther away, skies will gradual clear, clearing
first over the western/southern piedmont and sandhills, and last in
the vicinity of KRWI.
Pockets of MVFR fog may occur early Tuesday morning. Otherwise,
high pressure will begin to exert its influence on our weather.
A prolonged period of VFR conditions is anticipated across central NC
Tuesday through Saturday.
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