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Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000
FXUS62 KRAH 251846
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
245 PM EDT SUN SEP 25 2016

.SYNOPSIS...
-- Changed Discussion --A cold front will move into northern South Carolina and stall
this evening and overnight. High pressure will build south into our
region from New England tonight. The front will return north as a
warm front late Monday as a cold front approaches from the west.-- End Changed Discussion --

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --As of 245 PM Sunday...

Surface high pressure (1025+ MB) extended from NY state southward
into NC this afternoon. The high pressure was building south into
North Carolina, behind a cold front that was pushing into southern
sections of the state. The front separated two seasons, with summer
to the south and fall to the north. There were plenty of stratus
over VA into central NC in the cool and moist NE flow behind the
front, where temperatures were in the lower to mid 70s. Sunshine was
noted south of the front over SC into far southern NC where
temperatures were in the 80s.

There has been some dissolving of the stratus over the southwest
Piedmont and that trend will continue to near sunset. However, a
dense overcast will likely to hold especially along and north and
east of Interstate 40 from the Triad to Raleigh to Clinton with a
few thin spots through sunset.

Expect a thickening and lowering of the cloudiness over the Piedmont
overnight. Lows generally from 60 north into the mid 60s south. Only
a few patchy areas of light drizzle are expected in the western
Piedmont with only trace amounts of QPF.-- End Changed Discussion --

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
-- Changed Discussion --As of 245 PM Sunday...

Monday will be a murky day as hybrid CAD is expected to develop over
the western Piedmont as a warm/moist advection pattern sets up
between the surface and 850 mb. This occurs as the low level ridge
axis begins to shift east and the next cold front approaches the
Appalachians from the west. Expect the moisture profile further
increase though the day, except for the far eastern zones were some
drying will linger with the ridging. As a mid level trough and the
cold front approach the mountains late, the associated lift and
upslope easterly flow generate areas of rain. This will aid in
locking in the hybrid CAD over the damming region. This pattern will
persist overnight with rain likely in the west, spreading east into
the rest of central NC overnight. We will cap of POP in the high
chance category in the SE Coastal Plain through 12Z/Tue as they will
be farther away from the approaching trough and cold front through
then. Highs Monday from the lower 70s NW to mid 80s south. Lows
Monday night 65-70. QFP of 0.25 to 0.50 forecast for the NW with
less than 0.10 in the SE through 12Z/Tue.-- End Changed Discussion --

.LONG TERM /Tuesday through Saturday/...
As of 310 AM Sunday...

A cold front will make its way through the state on Tuesday as the
parent low pressure system becomes stacked over the Great Lakes. At
this point it looks like there will be hardly any punch at all with
this system and thus expect most of the precipitation to be in the
form of convective showers with isolated thunder possible Tuesday
afternoon, particularly across the south but otherwise instability
is lacking. The effects on temperature will not be seen until
Wednesday and beyond so expect highs on Tuesday near 80 degrees with
upper 70s across the north.

The real curiosities in the long term center around how the stacked
low will evolve over time. The GFS solution has the low remaining
embedded in the upper level flow and gradually moves eastward
keeping the end of the week dry. The ecmwf solution is much
different and is beginning to gain a little consistency with the
upper low cutting off from the mean flow and dropping south along
the Appalachians and hovering there for several days. This would
greatly increase precipitation chances over our area for the end of
the week and needs to be watched because the latest run of the GFS
is showing a bit of a trend toward that upper low dropping further
south although it has not cut it off yet. For now will keep the
forecast dry outside of slight chances for showers across the east
on Thursday but if this trend in the forecast continues, then pops
will need to be increased significantly for the end of the week.
Temperatures will drop back into the mid 70s for highs for the rest
of the week with lows in the middle 50s.

.AVIATION /18Z SUNDAY THROUGH THURSDAY/...
As of 145 PM Sunday...

IFR CIGS continue over a portion of the region this afternoon, with
the forecast of MVFR CIGS in the KFAY to KRWI terminals to develop
through the late afternoon. Overnight, IFR CIGS are expected to
remain or redevelop between 02Z-06Z. VSBYS should fall into the MVFR
range, possibly IFR with patchy drizzle from KRDU to KINT late
tonight.

Looking beyond 00Z/TUE, CIGS again will lower with areas of rain and
fog in the west, with an increasing chance of rain and fog in the
east. IFR to MVFR CIGS and VSBYS are expected Monday night into
Tuesday.

Conditions are expected to improve Wednesday and Thursday.

.RAH WATCHES/WARNINGS/ADVISORIES...
None.

$$
SYNOPSIS...Badgett
NEAR TERM...Badgett
SHORT TERM...Badgett
LONG TERM...Ellis
AVIATION...Badgett

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