Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 290739

Area Forecast Discussion
National Weather Service Raleigh NC
340 AM EDT Sat Apr 29 2017

A warm moist southerly flow will continue through the weekend, as a
strong high pressure remains anchored off the Southeast U.S. coast.


As of 340 AM Saturday...

It will definitely feel like summer today as central NC as an area
of high pressure at the surface and aloft extends across our region.
This abnormally strong high for this time of year will support high
temps a solid 10-15 degrees above normal ranging from the upper 80s-
lower 90s. The heating of the marginally moist and unstable air mass
may trigger an isolated shower or storm in vicinity of the
Yadkin/Pee Dee River Valley, though a mid level subsidence inversion
will provide a decent cap to prevent convection from popping across
the region.

Another night of warm/muggy conditions anticipated tonight. Skies
will start out mostly clear-partly cloudy though expect a deck of
low clouds to overspread the region from the south late this evening
into the overnight. Min temps upper 60s-near 70.


.SHORT TERM /Sunday and Sunday night/...
As of 340 AM Saturday...

Main adjustment to the Sunday-Sunday night period was to adjust max
temps up a few degrees from the previous forecast. Finding it
difficult to justify high temps as much as 7-8 degrees, primarily
over the western Piedmont, Sunday afternoon with little notable
change in the low level air mass. Surface and upper level ridge does
weaken with upper heights 30-50m lower than today, but warm/moist
sly flow will maintain the summer-like air mass. Morning clouds will
slowly depart in the afternoon, which should allow for at least
partial sun in the western Piedmont by mid afternoon. With
temperatures starting out near 70, should see temps recover into the
mid 80s across the west, upper 80s-near 90 in the east.

Some weakening of the mid level subsidence inversion and slightly
deeper moisture and instability will support isolated convection in
the late afternoon-early evening across the western half of central

May see an uptick in isolated showers late Sunday night, mainly
across the far west, as a s/w approaches from the southwest. This
system will may enhance convective coverage on Monday. Continued
warm and muggy with overnight temperatures once again in the 60s to
near 70.


As of 330 AM Saturday...

A shift in the longwave pattern next week will ultimately result in
lower heights over the eastern US and a ridge over the west.  The
sub-tropical ridge over the Southeast this weekend will shift east
Monday as a deep upper low lifts from the Southern Plains to the
Great Lakes.  The associated cold front and convective line will be
crossing the mountains early Monday, encountering more favorable
heating/instability in the west Monday afternoon before undergoing a
general downward trend in intensity as it progresses east Monday
night owing to a loss of better forcing and heating.  Still expect
PW over 1.5" and 60-80m height falls to support at least scattered
showers through central NC Monday night before moving to the coast
early Tuesday.  Highs Monday in the upper 70s to mid 80s.  Lows in
the mid 50s to lower 60s.

Temps will be knocked back top near normal briefly on Tuesday, but
with the secondary polar front holding to the north across VA, temps
will rebound into the mid 80s and above normal Wednesday.  the next
shortwave moving through the longwave trough is forecast to strongly
amplify over the Deep South Thursday, with medium range guidance
showing the potential for another cut off low near Tenn Thursday
night.  Models diverge quickly regarding out the eventual track of
the low, but the pattern will favor widespread precip late Thursday
and Friday, some of which could be heavy if the low slows and tracks
closer to the Southern Ablutions.   Temps are most likely to be
below normal int he upper 60s and low/mid 70s.


As of 120 AM Saturday...

Low level southerly flow around an area of high pressure anchored
offshore will advect moisture off the Atlantic overnight. This will
spread a deck of low stratus northward across central NC, resulting
in widespread IFR/LIFR ceilings across central NC. These ceilings
will likely persist through 14Z-16Z, afterwhich ceilings will lift
and dissipate with VFR parameters highly probable this afternoon-
early evening. An isolated shower or storm cannot be ruled out
across the western Piedmont, though probability of a shower or storm
affecting the Triad terminals is too remote to mention in the TAF at
this time.

Another round of IFR/LIFR ceilings are highly probable late this
evening through late morning Sunday. A few more isolated showers or
storms are possible Sunday afternoon, primarily over the western
Piedmont. IFR/LIFR ceilings are again likely late Sunday night
through Monday morning. Scattered showers and an isolated
thunderstorm and associated sub VFR ceilings/visibility are possible
across central NC Monday afternoon into Monday night as a cold front
approaches then crosses the region.

VFR conditions appear likely Tuesday and Wednesday.





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