Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 251842

Area Forecast Discussion
National Weather Service Raleigh NC
242 PM EDT Tue Jul 25 2017

A cold front will drop south across North Carolina today and then
stall across South Carolina on Wednesday. This front will lift back
north on Thursday before a strong cold front approaches the region
from the northwest on Friday.


As of 225 PM Tuesday...

Latest surface analysis shows the cold front making good
southward progress and stretching from near KPGV southwest to
KGSB to near KGSP. Surface dew points have already fallen into
the lower to mid 60s across the border counties with a dew
point of 64 noted at Roxboro and Henderson, just to the east
higher dew points in the lower 70s persist at KIXA and KASJ.
Aloft, the upper-level trough axis has shifted toward the coast.
Precipitable water values continue to fall and now range from
1.1" along the NC/VA border to around 1.6" across the south and
southeast. A weak short wave will drop into the region from the
northwest late tonight while a southwest-northeast elongated
upper level jet axis extends across the Southeast.

With decreased moisture, a weakly unstable air mass and limited
forcing, precipitation chances will be limited this evening and
tonight. The only organized area of convection near our CWA
will likely be scattered storms across the coastal region near
the surface front and another area of isolated convection across
the higher elevation of the NC mountains. Given the higher dew
points in the lower 70s lingering across the Coastal Plain and
Sandhills and slightly better mid- level lapse rates, could see
a shower pop up in the east or a shower in the higher
elevations move into the western Piedmont. Will include slight
chance pops tonight.

Expect periods of cirrus tonight with the enhanced upper level
jet. A layer lower stratus may develop late tonight in an arc
from the Coastal Plain west and northwest across the Sandhills
and into the Yadkin Valley. It will be cooler tonight with a
some lows reaching the upper 60s across the northern Piedmont,
especially near the VA border with most locations ranging from
67 to 74 degrees. The EC ensemble guidance for Henderson gives
an operational and a mean low both of 67 with the warmest
ensemble member giving a low of 69 and the coldest 63!


As of 240 PM Tuesday...

The cold front should be positioned south of central NC on
Wednesday morning allowing high pressure to extend into the
region from the north. The front will begin lifting north on
later Wednesday as the surface flow veers to southeasterly and
southerly. This will allow an increase in moisture roughly in
the 925 to 850 hPa layer and promote an increase in cloud cover
and perhaps a shower or storm, generally in an arc from the
Coastal Plain west and northwest across the Sandhills and into
the Yadkin early in the day that will expand northward during
the afternoon and evening. Precipitation chances will be limited
to the slight chance range across most of the area, so all in
all it will be a much cooler and more tolerable day. Highs will
range in the upper 80s to near 90 with lows in the 68 to 74
range. -Blaes &&

As of 320 AM Tuesday...

Thursday is expected to be a relatively dry day as upper flow over
central NC remains zonal and a surface low passes to the north of
the area. The attendant cold front to this low is expected to drop
southward across the area on Friday. The upper trough becomes deeper
than in yesterday`s simulations and helps to now push the front
completely through the area by Saturday afternoon. This will keep
the best chances for showers and storms between 18z Friday through
12z Saturday. Continental high pressure to the northwest dries out
the area, keeping weather settled through Sunday before a wave out
of the Gulf of Mexico becomes a player early next week.

Highs in the upper 80s to low 90s Thursday and Friday will drop into
the mid 80s for the weekend into early next week. Lows in the low to
mid 70s early in the time frame will drop into the upper 60s to low
70s for the later stages of the long term forecast.


As of 200 PM Monday...

24-Hour TAF period... Central NC is under the influence of high
pressure to the north with a cold front stalled south of the
area in SC and GS. This will result in VFR conditions across
much of central NC through Wednesday afternoon with the
exception of some morning MVFR stratus and fog across the south
which may impact the KFAY terminal. An isolated shower or storm
is possible across the Southern Coastal Plain, Sandhills and
souther/Western Piedmont. But with limited and coverage and
confidence, will omit from the TAF. Otherwise, expect periods
of fair weather cumulus this afternoon and periods of BKN cirrus
clouds. A layer lower stratus the VFR and MVFR range may
develop in an arc from the Coastal Plain west and northwest
across the Sandhills and into the Yadkin Valley late tonight and
Wednesday morning. Light north to northeast winds at less than
10kts will continue through the period before veering to
southeasterly on Wednesday afternoon.

Looking ahead... The cold front to the south will lift north as
a warm front on Thursday before a stronger cold front moves
through the area on Friday and then stalls to our south over the
weekend. Mainly VFR conditions expected through much of the
period with scattered mainly afternoon and evening showers and
thunderstorms and a chance of morning fog and stratus. The
greatest chance of adverse aviation conditions in showers and
storms will be Thursday night through Friday night ahead of the
approaching cold front. -Blaes


The KRAX WSR-88D will be down for the Service Life Extension
Upgrade (SLEP) beginning this morning and likely lasting through
Thursday or Friday.

The temperature & dew point sensor at site KFAY, located at the
Fayetteville Regional Airport, is malfunctioning. NWS technicians
have turned the sensor off and ordered parts to repair it. At
this time, we expect the sensor to be returned to service early
next week.




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