Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 212316

Area Forecast Discussion
National Weather Service Raleigh NC
716 PM EDT FRI OCT 21 2016

An upper level trough and attendant cold front will track east
and off the coast this evening. Much cooler and drier air will
overspread the state tonight and Saturday.


As of 650 PM Friday...

The showers have all but ended in the far eastern Coastal Plain
associated with the cold frontal passage. We updated to eliminate
the shower chances for the remainder of the evening in all areas.
True CAA, DAA have arrived in the NW Piedmont where dew points were
in the upper 30s to lower 40s at 650 PM. Dew points in the east were
still in the 60s. Temperatures have already fallen into the upper
50s in the NW Piedmont, but remained near 70 in the SE. CAA will
bring these readings down into the 50s and lower 60s by midnight.

Behind the front, skies were clearing rapidly. We will speed up the
clearing currently forecast by a few hours. By late evening, skies
should be mostly clear, except partly cloudy in the NW zones where
stratocumulus will periodically make it out over the NW Piedmont
this evening. Winds also have been increased to indicate the 30-35
mph gusts for a few more hours this evening in the NW, and 20-25
mph gusts elsewhere through midnight or so. Winds will decrease
after midnight to around 10 mph, but will gust to 15-20 mph over the
Piedmont. Lows in general should be in the 40s in all areas.


As of 320 PM Friday...

Thicknesses crash to ~1330m tonight, with very little recovery on
Saturday as cold advection continues. Dry adiabatic mixing to
850mb yields upper 50s to mid 60s, with clear skies and a 10-15mph
northwest wind that will gust to 20-25mph. Winds will again weaken
Saturday night, possibly enough so to decouple across the southern
and western Piedmont as high pressure builds in from the
southwest. Areas that decouple will see lows in the upper 30s
given thicknesses again below 1340m, with low/mid 40s elsewhere.


As of 230 PM Friday...

Dry weather is expected for the end of the weekend through the
middle of the upcoming work week.

The general weather pattern during the extended period will feature
an exiting high amplitude upper trough early Sunday followed by
rising heights and a dry northwest to west-northwesterly flow through
late Wednesday with a dry cold front dropping across the region
on Monday. A short wave ridge will move across the region on
Wednesday night as troughing approaches the Appalachians on Thursday
and moves offshore on Friday.

The sensible weather will feature dry weather through the period
with near zero PoPs through early Wednesday night. After a chilly
start to the weekend, temperatures will modBreezy NW winds will
redevelop on Saturday, sustained at 10-15 kt with gusts up to 20-25
kt, becoming westerly and weakening Saturday night and Sunday.erate
on Sunday and especially Monday. Have adjusted maxes up a degree or
two on Sunday and several degrees on Monday. Even though a cold
front will move across the area on Monday, it appears the cold
advection will lag the fropa in central NC allowing temperatures to
moderate. The 10/21 00Z ECMWF ensemble guidance for RDU has a mean
of 77 on Monday, the warmest has 80, coolest has 72, and the
operational ECMWF has 75. Worth noting that consensus 1000-850
thickness values jump from Sun to Mon and range between 1365 and
1375m on Monday morning. Temperatures cool down a bit behind the
front on Monday night through Tuesday night.

Some uncertainty arrives for the end of the period as two northern
stream waves drop into the western Great Lakes on Thursday and shift
east on Friday. The 12Z GFS and ECMWF have cBreezy NW winds will
redevelop on Saturday, sustained at 10-15 kt with gusts up to 20-25
kt, becoming westerly and weakening Saturday night and Sunday.ome
into better agreement and suggest some slight chance PoPs are
warranted for Thursday night and early Friday across the north and


As of 715 PM Friday...

Sfc cold front and attendant band of showers and a few storms(in the
east)have pushed east of the forecast area. Post-frontal dry cold
air advection will continue to spread east, resulting in clear skies
overnight. The post-frontal cold air advection will also keep winds
up overnight, with NWLY wind gusts of 17 to 23 kts gradually
diminishing, with sustain winds between 7 to 10kts.

Cool high pressure building into the region will support dry VFR
conditions. Breezy NW winds will redevelop on Saturday, sustained at
10-15 kt with gusts up to 20-25 kt, becoming westerly and weakening
Saturday night.

Looking Ahead:  VFR conditions are expected to rule for the
remainder of the weekend and through the majority of next week.




NEAR TERM...Badgett
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