Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000
FXUS62 KRAH 220116
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
916 PM EDT Mon May 21 2018

.SYNOPSIS...
A moist and unstable air mass will remain entrenched across central
NC through the middle of the week. A cold front will move through
the area on Wednesday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 916 PM Monday...

An outflow-augmented back-door cold front, which has been the foci
for the slow moving convection and torrential rainfall
over the past several hours, has surged south-southwest across
the northern half of the forecast area, and has just settled south
of the US Highway 64 corridor, where it is forecast to eventually
dissipate over the next couple of hours.

Ongoing convection across the area is expected to gradually
diminish over the 3 to 4 hours, as the BL continues to stabilize
due to both convective turn-over and nocturnal cooling.
Under mostly cloudy conditions, lows overnight in the
mid 60s north to lower 70s south. Additionally, patchy fog
is possible, esp in areas that experienced heavy rain.


&&

.SHORT TERM /Tuesday through Tuesday night/...
As of 315 PM Monday...

The boundary that`s currently over our area is expected to lift back
to the north by 12Z Tuesday.  However, there is some indication in
models that a weak mid-level short wave moving up from the south
could prolong the risk for showers across our north/northeast zones
between daybreak and noon Tuesday. However, once this feature
passes, a pocket of dryer air in its wake should give us a brief
break in rain chances during the afternoon, esp across across the
eastern half of our CWA.

By Tuesday evening and night, we`ll turn our attention to a cold
front approaching from the northwest (the system currently across
the northern/central Plains).  Models suggest that pre-frontal
shower and thunderstorm activity will begin approaching our western
zones as early as Tuesday evening, with best chances for rain across
our western and central zones overnight into Wednesday morning.

With little change in the airmass, expect highs Tuesday again in the
low-mid 80s and lows Tuesday night in the upper 60s.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
As of 235 PM Monday...

The subtropical ridge off the Southeast coast will keep central
North Carolina in a tropical airmass on Wednesday.  A frontal zone
dropping southward from the Mid Atlantic will enter northern parts
of the region Wednesday night and become stationary close to the
NC/SC border on Thursday.  The tropical airmass will be suppressed to
the south of the boundary Thursday and Friday before returning
northward into central North Carolina over the holiday weekend. In
addition, a tropical low is forecast to move northward across Cuba
and the Gulf of Mexico/Florida over the holiday weekend and early
next week.

Diurnal heating combined with the frontal boundary will generate
scattered convection Wednesday afternoon and evening. Scattered
convection Thursday and Friday should be limited to locations near
the NC/SC border and western Piedmont. Convection will overspread
the entire region over the 3-day holiday weekend with the return of
a tropical airmass and close proximity of the tropical low.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
As of 817 PM Monday...

Ongoing cluster of thunderstorms across the central Piedmont
will impact KRDU through 02 to 03z, resulting in IFR to MVFR
ceilings and visibility restrictions. Elsewhere, convection has
weakened significantly across the area. As such, do not expect any
significant aviation impacts from storms at KINT, KGSO, KRWI, and
KFAY. Areas of fog/stratus will be apt to form between 06 to 12z,
especially in/near areas that receive heavy rain. Any sub-VFR cigs
Tuesday morning will quickly lift to VFR with heating. Convective
rain chances Tuesday afternoon are expected to be significantly
lower than today, generally isolated to widely scattered.

Outlook: A cold front will push SSE through the area late Wednesday
and Wednesday night. Numerous showers and thunderstorms are expected
to accompany the cold front. With the cold front forecast to stall
south of the area Thursday and Friday, expect drier conditions
through the remainder of the work week. However, rain chances will
be on the increase on Saturday as moisture overspreads the area
from the south.


&&

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

&&

$$

SYNOPSIS...np
NEAR TERM...CBL
SHORT TERM...np
LONG TERM...Franklin
AVIATION...CBL


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