598
FXUS62 KRAH 140619
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
220 AM EDT Wed Aug 14 2024

.SYNOPSIS...
High pressure centered over the Great Lakes will shift east and
southeast into the mid Atlantic and the eastern Carolinas through
Friday and then shift offshore Saturday. A cold front will approach
the region from the west on Saturday.

&&

.NEAR TERM /TODAY AND TONIGHT/...
As of 220 AM Wednesday...

Areas of fog have begun to develop in the last hour or so, mainly
across the northern/northwest Piedmont into the northern Coastal
Plain. Satellite imagery reveals much of the mid/high clouds have
exited to the south and east. This trend should continue, although
some patchy 10 kft clouds may still exist across our southern zones.
Much of these low visibilities have developed where rain fell Tue.
Based on latest observational trends and model guidance, a dense fog
advisory may be needed for portions of the Piedmont and Coastal
Plain, mainly along/north of US-64. We will continue to monitor.

For the rest of today, northwest flow will persist through the
period. Another shortwave will dive down from OH/VA, skirting our
northeastern zones before exiting offshore later tonight. High
pressure will slowly build south from the OH valley into the Mid-
Atlantic states, resulting in a light NE flow. Highs this afternoon
should be warmer than Tue thanks to more sunshine, with low to
middle 80s. This is slightly below normal for mid-August. Afternoon
cumulus will develop at peak heating, and some CAMs still suggest a
few widely isolated showers or a storm could develop in the aftn/eve
as the shortwave aids some 250-500 J/kg of CAPE. Rain chances should
be 20-percent or less overall given lack of appreciable forcing,
with any isolated showers tapering off after sunset.

Tonight, with generally clear skies and calm winds, lows should
manage to dip some 2-6 degrees below normal in the upper 50s in
outlying areas to low to mid 60s elsewhere. This will certainly be a
comfortable night we have not seen in some time.

&&

.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
As of 220 AM Wednesday...

Ridging aloft over the Midwest and OH valley will gradually pivot
east into the Mid-Atlantic as an upper trough tracks into the Great
Lakes region. High pressure will continue to nose down into our area
from the northern Mid-Atlantic. Temperatures will be perhaps 1-2
degrees warmer than Wed owing to a slight rise in low-level
thicknesses, in the low to mid/upper 80s. This is just below
average. We will again see some afternoon fair weather cumulus.

The aforementioned trough will combine with low to mid-level WAA
across the TN/OH valleys Thu night, increasing some mid/high clouds
across the western Piedmont. The WAA will likely generate some
upstream convection as far south as the TN/KY region, but it will
not reach us due to high pressure and its stability. Lows should be
comfortable again, ranging from the low to middle 60s, lowest in the
Coastal Plain.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
As of 310 PM Tuesday...

Aloft, nwly flow will promote dry conditions Thursday and for much
of Friday. Flow will turn more swly late Friday and persist through
early next week over central NC.

Thursday through Friday: PWAT is forecast to drop to 60 to 80 %
below normal on Thursday as high pressure slides down the Atlantic
coast. Dry weather will result as afternoon dew points mix out into
the lower 60s. Temps will peak near normal, in the mid to upper 80s
Thursday afternoon. With calm winds, and minimal cloud coverage,
overnight lows should dip into the mid 60s.

Flow aloft will primarily remain wnwly Friday, promoting another day
of mostly dry conditions. However, later in the day, some deeper
moisture will start to trickle into the mountains/foothills. As
such, a few afternoon mountain showers/storms may trickle into our
far northwest to northern locations. Overall though, ensemble
probabilities for measurable rain remain low even in these
locations. Highs will once again reach the mid to upper 80s.
Overnight lows in the mid to upper 60s are expected Friday night.

Saturday through Tuesday: Flow aloft will finally turn more swly
Saturday and persist through Tuesday as general troughing anchors
over the eastern US. Associated increasing moisture flux into the
southeast ahead of a sfc cold front will increase the chances for
showers and storms each afternoon/evening. However, spatial and
temporal predictability this far is out is pretty low at this point.
As such, decided to maintain just slight to low chance POPs peaking
each afternoon.  Temps will hover the mid to upper 80s through this
period.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
As of 125 AM Wednesday...

The main forecast challenge with the 06z TAF issuance is the
potential for fog early this morning. Latest satellite imagery still
reveals some low to mid-level clouds across the area. Clearing,
however, is expected to build south from VA into the morning hours.
Where rain has occurred across the northern Piedmont and northern
Coastal Plain has resulted in current VIS ranging from LIFR to IFR.
Based on latest observational trends, model guidance, and the
rainfall footprint, highest confidence of IFR or lower VIS is at
GSO/RDU/RWI and lesser at FAY given more clouds at this terminal.
Confidence was not high enough to include LIFR restrictions, but
this cannot be ruled out at GSO/RDU/RWI early this morning. VFR
should prevail the rest of today with light NE winds and VFR cumulus
in the 4-7 kft range. An isolated shower is possible nearly anywhere
this afternoon/evening but coverage is too low to mention in the TAF.

Looking beyond 06Z Thurs, generally fair weather with VFR conditions
are expected across the area into Friday as high pressure extends
into the area. A cold front will approach this weekend producing a
limited threat of an afternoon or evening shower/storm across the
west on Friday with a marginally greater chance of mainly afternoon
and evening showers and storms for Saturday and Sunday.

&&

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

&&

$$
SYNOPSIS...Kren
NEAR TERM...Kren
SHORT TERM...Kren
LONG TERM...Luchetti
AVIATION...Kren/Blaes