Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 241942
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
340 PM EDT Mon Jul 24 2017

.SYNOPSIS...
A surface trough will extend from central Virginia southwest into
central North Carolin through tonight. A cold front will drop south
into the region late tonight and on Tuesday. The front will stall
across the Carolinas on Wednesday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 340 PM Monday...

The latest surface analysis shows a surface trough extending
southwest from the northern Chesapeake Bay into the Piedmont of NC.
A cold front extends from southern New Jersey west to southern Ohio
and then into western Kentucky. Further aloft, a moderate amplitude
trough extends south from the eastern Great Lakes into the Carolinas
with the last short wave trough sweeping across western VA and NC
early this afternoon. The air mass across central NC continues to
dry out from the northwest with precipitable water values now
ranging from 1.3" near KGSO to around 1.8" near KFAY. The air mass
has also cooled down with the 1000-850 MB thickness values about 20m
lower than yesterday day at this time at KGSO and KRNK with less
cooling, around 10m at KMHX.

The radar this afternoon is rather quiet with fairly widespread
convection across portions of GA and SC and scattered storms across
parts of VA and WV associated with the cold front. Convection
allowing models suggest storms will be isolated across central NC
this afternoon and evening. GOES-16 visible satellite imagery shows
some cumulus enhancements in the U.S. route 1 corridor, a few of
these are apt to develop into showers and perhaps a few
thunderstorms with the greatest storm threat across the southern
Coastal Plain and Sandhills. Convection upstream in VA and WV are
apt to weaken before reaching central NC. The atmosphere today is
less unstable than previous days with afternoon MLCAPE values
ranging between 800 and 1800 J/Kg range. Bulk shear values range
between 15 and 20 kts. Storm coverage will be less than previous
days with much weaker intensity.

Skies should average partly cloudy overnight with lows similar or
perhaps a degree or two cooler than previous nights, bottoming out
in the 71 to 77 range. -Blaes

&&

.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
As of 230 PM Monday...

The main portion of the upper level trough across the Northeast and
Mid Atlantic shifts east and lifts on Tuesday and Tuesday night
while a shear axis lays down east-northeast to west-southwest from
near Cape Hatteras to central GA. The latest GFS and EC both try to
close off a portion of the shear axis over eastern GA and the SC
coast. At the same time, the associated cold front drops south into
NC on Tuesday afternoon and evening and then stalls toward the NC
and SC border by daybreak Wednesday. This is a more aggressive and
southward solution than recent model runs. This trend would tend to
confine precipitation further south and east and could result in
additional cooling across our northern tier with the possibility of
a layering of additional stratus and then some clearing near the VA
border. Not ready to jump all in on this solution, but have trended
the forecast that way.  Highs on Tuesday will range in the lower 90s
but could be cooler near the VA border if the cooler air is
aggressive. Lows Tuesday night will range in the 68 to 75 range.
-Blaes
&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
As of 220 PM Monday...

Surface high pressure over the northeastern CONUS will extend into
the region on Wednesday as a frontal zone lingers south of the CWA.
This will be our first break from 90 degree temperatures as highs
are expected to be in the mid to upper 80s. This high will remain
over the area on Thursday as well although max temperatures will
climb into lower 90s. Although diurnal showers and a possible
thunderstorm cannot be ruled out, these days should be fairly dry.

By Friday, a developing low pressure system, spurred on by a
shortwave upper trough, will cross the mid-Atlantic states and move
off the coast. As it does so, an east-west oriented front will sag
southward towards central NC. Timing in both the GFS and ECMWF
solutions is fairly similar and it looks like enhanced precipitation
will begin at some point Friday afternoon/evening and continue
through the weekend. Highest chance for rain will lie across eastern
areas Sunday and Monday. After a brief stint back in the 90s on
Friday, temperatures will return to the mid to upper 80s through
Monday.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
As of 210 PM Monday...

24-Hour TAF period... VFR conditions are expected to be common
across central NC outside of some residual stratus in the Coastal
Plain near the KFAY terminal early this afternoon, areas of morning
stratus in the Coastal Plain on Tuesday morning, and local
restrictions in an isolated shower or thunderstorm. isolated showers
and storms will develop this afternoon and could persist into the
evening, mainly across the Coastal Plain and Sandhills. West to
southwest winds at 5 to 10kts will become light northerly after
midnight.

Looking ahead... Primarily VFR conditions are expected through much
of the work week with scattered, mainly afternoon and evening
showers and thunderstorms expected, especially toward the end of the
period. Areas of late night and morning stratus can be expected,
especially Thursday into Saturday. -Blaes

&&

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

&&

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

&&

$$
SYNOPSIS...BLAES
NEAR TERM...BLAES
SHORT TERM...BLAES
LONG TERM...RE/Franklin
AVIATION...BLAES
EQUIPMENT...BLAES


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