Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC-- Remove Highlighting --
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FXUS62 KRAH 012355
Area Forecast Discussion
National Weather Service Raleigh NC
655 PM EST Thu Dec 1 2016
A departing cold front will push off the Southeast coast today.
High pressure will build over the Eastern U.S. from the west today
into the weekend. Upper level disturbances will approach the
eastern U.S. from the north and west on Sunday and from the
southwest on Monday bringing an increasing chance of precipitation
for late Sunday and again late Monday into Tuesday.
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
As of 320 PM Thursday...
Early afternoon surface analysis shows the cold front now well off
the Carolina coast with a lee trough across the western Piedmont.
A much drier air mass has moved into the area with surface dew
points in the 30s to lower 40s with a dew point of 27 at KINT at
20Z. Deep layer moisture is also much reduced with the
precipitable water value at KGSO from this morning`s 12Z sounding
at 0.32 inches. Given large scale subsidence tonight and the drier
atmosphere, skies will be mainly clear with perhaps a few high
clouds coming in from the west late overnight. Winds will relax
overnight which along with a cooler and drier air mass, should
result in considerable cooling with lows in the 33 to 39 range.
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/...
As of 205 PM Thursday...
Surface high pressure will build into and over the region through
Saturday with westerly flow aloft. As a result, expect this period
should be mainly dry, with rather seasonable temperatures (highs in
the mid 50s and lows in the low to mid 30s). There is a slight
chance that rain could move into the far west Saturday night,
however it is more likely they will hold off until sometime on
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
As of 335 PM Thursday...
The extended forecast will be characterized by a series of
shortwaves progressing through the central U.S. Though the model
solutions are in much better agreement for Sunday through Tuesday,
significant model differences arise thereafter. As a result,
forecast confidence beyond Tuesday is quite low.
Sunday through Tuesday: An upper level cut-off low over NW Mexico
will usher a good amount of moisture into the Gulf Coast states and
southeast U.S. Sunday while a weak ridge lingers over the east
coast. Meanwhile, a northern stream shortwave over the Midwest will
progress eastward, though the impact it will have on the ridge is a
bit uncertain and will have an impact on the northeastward extent of
the Pacific moisture. The better chance for rain to move into the
region will come Monday and Tuesday as the aforementioned low starts
to move northeast through the Midwest and interacts with another
shortwave traversing a strengthening trough over the Rockies. The
advection of additional moist air being picked up off the Gulf in
the southwesterly flow will result in increasing chances for rain
over the Carolinas. Highs Sunday will still be somewhat cool, upper
40s to low 50s before warming up into the mid to upper 50s Monday
and Tuesday. Lows will generally be in the upper 30s to low 40s.
Wednesday and Thursday: The low should be absorbed into the northern
stream flow by late Tuesday/Tuesday night and the rain should exit
to the east Tuesday night. Though the upper level patterns appear
similar on Wednesday and Thursday, the difference in the strength
and location of the next low/trough is significant. As a result,
forecast uncertainty is high with respect to both weather and
temperatures. Per the GFS...Central NC could get a quick shot of
rain followed by strong cold advection and the chance to see lows in
the low to mid 20s Thursday night. Conversely...the ECMWF is
stronger and slower with the system and given the latest solution,
the rain would be delayed until late Thursday/Thursday night. For
now, will keep this period dry with highs in the mid 50s to low 60s
and lows decreasing from 40s Wednesday night to 20s and 30s Thursday
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --As of 655 PM Thursday...
24 Hour TAF Period: High confidence of VFR conditions through the 24
hour TAF period. Surface high pressure will build/extend into the
area through the remainder of the work week with mostly clear/mostly
sunny skies expected. Winds will become light and variable
overnight, then increasing after sunrise out of the west to
northwest in the 5 to 10 mph range.
Outlook: Fair weather is expected to continue into the weekend as
surface high pressure builds/extends into the region. Mid and high
level cloudiness will increase and thicken on Saturday and lower and
thicken into early Sunday. A series of upper level disturbances will
bring increasing chances of adverse aviation conditions into the
area late Sunday and then late Monday especially Tuesday.
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