Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 250150
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
950 PM EDT Fri Mar 24 2017

.SYNOPSIS...
An area of high pressure anchored offshore will extend west into
central NC through Saturday. A weakening upper disturbance will
cross our region on Sunday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 950 PM Friday...

Mid/upper level ridge centered over the region this evening will
shift offshore overnight in advance of the closed cyclone advancing
east across the southern central Plains. This will allow for a
marked increase in high-level moisture from west to east after
midnight, which based on IR imagery, be sufficiently opaque enough
to impede radiational cooling. Mild overnight lows generally in the
50s(~ 7 to 10 F degrees above normal).

Sfc ridge axis extending into the area from the parent high centered
off the Carolina coast, should maintain it`s influence across the
area overnight, which will result in only modest/marginal low-level
moisture recovery overnight, and thus should further limit fog
development.

&&

.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
As of 250 PM Friday...

Warming trend continues Saturday as the high continues to drift away
from our region, while an area of low pressure lifts from the
southern Plains into the mid MS Valley. The approach of this feature
will deepen our sw flow, increasing the moisture advection. This
will lead to increasing cloudiness. While the atmosphere moistens,
little if any lifting mechanisms noted to generate precip, aside
from afternoon heating, Saturday through Saturday evening. Still,
could see an isolated shower or two over the southern Piedmont but
probability and coverage is too remote at this time to mention in
the forecast. The warming air mass will translate to afternoon
temperatures in the 70-75 degree range.

Clouds will thicken and lower across the area Saturday night. This
blanket of clouds will trap the heat gained Saturday, resulting in
overnight temperatures in the 50s. A lead s/w ahead of the main low
pressure system over the mid MS Valley will support a band of
showers that will cross the mountains overnight, and may be in
vicinity of the Yadkin River just prior to daybreak. Will retain the
slight chance PoP over our western periphery late Saturday night.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
As of 240 PM Friday...

A deep low pressure system will lift northeast into the Great Lakes
Sunday. Its associated cold front will be weakening and essentially
stalling as it edges up against the mountains Sunday and the parent
low moves further northeast. This will result in central NC being
nicked by only a glancing blow from the stronger dynamic regime
associated with the upper system. So, despite our increasingly warm
and moist airmass, convection will be favored northwest, with
progressively smaller chances heading southeast. Some areas east of
I95 may not see any activity at all. Will also maintain small
chances for thunder west during the afternoon as instability will be
modest and the east will be strongly capped in proximity to the
Bermuda high offshore. Highs will reach the low to mid 70s, but the
northeast may struggle to reach upper 60s due to heavier cloud
coverage and potential shower activity.

Warm and moist airmass remains in place in return flow around the
Bermuda high with isolated convection on Monday and highs mostly in
the upper 70s. A rather weak, but more southerly tracking short wave
will be approaching from the west on Tuesday to increase our chance
of convection somewhat due to its moving through during the heat of
the day. Not seeing forcing that would readily signal potentially
strong or well-organized convection, though, so will maintain 40-50
chance PoPs. Tuesdays highs will again climb way up into the 70s,
with some lower 80s likely across the southern tier. Highs will
again reach upper 70s Wednesday, but only isolated showers look
doable in weak westerly low level flow and upper ridging over the
area.

Cooler high pressure makes a surge down the Atlantic coast on
Thursday, with a backdoor cold front threatening to make it as far
south as central NC, but low confidence in picking a model solution
at this point. We will concurrently have a more southerly low
pressure system taking shape over the southern Midwest which would
feed moisture into the frontal zone and potentially give us a rain
period Thursday night and Friday.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
As of 840 PM Friday...

24 Hour TAF Period: High pressure anchored offshore will allow for a
light south to southwesterly wind overnight along with a
continuation of increasing moisture. We may see some patchy sub-VFR
conditions develop late tonight/Saturday morning, though confidence
remains low. KGSO/KINT stand the best chance of seeing any sub-VFR
conditions, with possibly some sub-VFR cigs developing Saturday
morning from 13-16Z or so, before lifting to VFR. Otherwise, VFR
conditions are expected Saturday, with south to southwesterly winds
around 10-12 kts, with some gusts of up to 20 kts.

Outlook: The threat for showers appear minimal through Saturday,
though the potential appears higher for late Saturday night into
Sunday, along with the potential for some patchy sub-VFR cigs/visbys
early Sunday morning. Periods of MVFR/IFR ceilings and visibility
due to fog appear probable Sunday night through Wednesday. The
highest threat for scattered showers will be on Tuesday when another
upper disturbance passes primarily to our north.

&&

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

&&

$$
SYNOPSIS...WSS
NEAR TERM...CBL
SHORT TERM...WSS
LONG TERM...mlm
AVIATION...BSD/WSS


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