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Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC
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320
FXUS62 KRAH 010600
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
1255 AM EST Wed Feb 01 2017

.SYNOPSIS...
Mild southwesterly flow will continue ahead of a cold front that
will settle south across NC this evening. Cooler high pressure
will follow for Thursday and Thursday night, followed by colder
conditions Friday and Saturday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1255 AM Wednesday...

The latest satellite data indicated plenty of cirrostratus upstream
heading to the ESE. This supports the latest guidance in brining in
high level cloudiness this morning, which should help keep lows
mostly in the 40s. The NAM/GFS/RAP all suggest enhancement to the
cirrus after 09Z over VA and northern NC.

Today will bring another very mild day with a prefrontal surface
trough out ahead of a cold front that will be approaching from the
north by late afternoon. Models indicate dry conditions with the
front as moisture will be lacking. However, there will be enough
high level moisture for partly sunny to mostly cloudy skies at
times. Highs today should easily reach well into the 60s again, with
70s in the south and east. The wind shift to the north will not
arrive until very late day in the northern zones, and in the south
during the evening. Mid level cloudiness will be on the increase
behind the front tonight, which may negate some of the CAA affects.
Lows tonight will be in the upper 30s north, ranging into the 40s
south.

&&

.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
As of 1255 AM Wednesday...

The backdoor cold front will settle south of the NC/SC border
Thursday as another Alberta clipper wave dives SE though the Lakes
into New England. One weak high pressure will move offshore of the
Mid-Atlantic coast Thursday, followed by the approach of a much
stronger Polar high pressure Thursday night and Friday. However, the
CAA will be delayed with this high until Friday - as the reinforcing
cold front will be delayed until late Thursday and Thursday night
for our region. So, Thursday and Thursday night central NC will be
in between systems - with essentially neutral advection - and dry
conditions. Highs will be cooler (upper 50s and 60s) but still well
above the 30 year average. CAA will commence Thursday night - as the
Polar front settles through the region. Models indicate plenty of
mid level moisture associated with mid/upper level disturbances that
may affect lows. Right now it appears that at least partly cloudy
skies can be expected, becoming cloudy late. Lows generally in the
30s expected, with near 40 SE.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 1255 AM Wednesday...

Friday`s forecast will depend on the strength of approaching
mid/upper level wave, amount of cold air in place, and timing of
light precipitation (if any) during the day. Current thinking is
that if any light wintry precipitation falls Friday, it will be
very low impact if any, and confined to the early morning. Road and
ground temperatures will have been warm for many days - and even the
lows before any light precip begins Friday morning may not even
fall below freezing. Much more to come in later forecasts.

With WNW flow aloft in the wake of Friday`s departing short wave,
sfc high pressure and drier colder airmass will briefly build across
the area for Saturday. Highs on Saturday will only reach the mid-upr
40s despite ample sunshine.

The next weather system will then approach from the NW Saturday
night and move across the area Sunday morning and afternoon. While
forecast soundings show a well-defined developing warm nose and
partial thicknesses are in a warming trend at that time and suggest
Sunday`s p-type will be all rain, my concern right now is the
antecedent low level dry air and cold airmass in place over our area
(forecast low temps early Sunday morning are in the upper 20s).  If
the precip were to move in faster than currently forecast, I
wouldn`t be surprised to see a very brief mix of p-types Sunday
morning across our NW Piedmont zones before quickly changing to rain
as the morning progresses. If that happens, impacts should be
minimal given brief duration. It`s worth noting that the latest
ECMWF is somewhat faster than the GFS with the precip arrival, and
consequently it`s low level thicknesses are colder and support the
aforementioned mixed p-type scenario at the onset. Nevertheless,
this system will be quick-moving and gone by Sunday evening, but not
before leaving the daytime Sunday cloudy, damp, and chilly with
highs in the 40s (coldest NW).

For the first half of next week, look for a warming trend as a
longwave trough deepens in the  middle of the country.  Highs Monday
and Tuesday will climb to the mid-upr 60s, and lows falling back
only into the 40s. Rain chances Monday through Tuesday will be
mostly confined to Monday night and across our northern zones as a
short wave passes by to our north during that time.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
As of 1255 AM Wednesday...

VFR conditions expected for the next 24 hours, with only mid and
high cloudiness at times through the period.

Outlook: A weak wave of low pressure will develop along the coast
Fri, at which time a period of light rain and sub-VFR conditions may
result in central NC. Another fast-moving frontal system will bring
another chance of rain and sub-VFR conditions to the area on Sunday.

&&

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

&&

$$
SYNOPSIS...MWS/Badgett
NEAR TERM...Badgett
SHORT TERM...Badgett
LONG TERM...Badgett/BSD/NP
AVIATION...MWS/Badgett
National Weather Service Regional Headquarters
