423
FXUS62 KRAH 222354
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
654 PM EST Fri Nov 22 2024

.SYNOPSIS...
Low pressure will remain across the Northeast tonight into Saturday,
eventually moving northeast into Canada. Meanwhile, high pressure
will build into the Southeast from the Plains.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 235 PM Friday...

A surface low will linger around New York City through midnight
before starting to shift offshore to the east. Any precipitation
from this storm will remain to the north across Virginia or west
across the Appalachian Mountains. Mid level clouds currently across
southern counties in the forecast area are shifting south while high
clouds are moving into the state from Virginia. The clouds should
not make too much southward progress this afternoon before
retreating back into Virginia overnight, leaving mostly clear skies.
As mentioned in the midnight shift AFD, the GFS remains an outlier
compared to other models showing a mixed atmosphere and gusty winds
continuing through the night. Most other models show the surface
winds decoupling, although still remaining around 10 kt overnight,
which is the solution the official forecast is following. The
steadier wind compared to last night should allow overnight lows to
remain warmer than last night, although the expected values between
35-40 are near normal.

&&

.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
As of 235 PM Friday...

The Northeastern surface low should continue to move up the Atlantic
coast towards eastern Canada, and this pattern will allow west-
northwest wind to continue across the region. Mostly sunny skies are
expected tomorrow, except there could be a little more cloud cover
across the Triad. Wind gusts will continue, although values
shouldn`t be higher than 20 mph. Highs should be about 10 degrees
warmer than today, ranging from the mid 50s to the low 60s.

With high pressure settling in across the Southeast tomorrow night,
skies will be clear and the wind should significantly drop off,
going calm in some areas. Although Saturday night does not look as
cold as last night, with temperatures mostly staying above freezing,
there will still be frost possible. This will only be highlighted in
counties where the growing season has not ended. This area was
announced earlier this morning in a Public Information Statement
along with maps on social media, generally locations east of US-1.
Where the growing season continues, the threat of a widespread
freeze appears minimal at this point. Forecast lows across central
North Carolina will be in the 30s.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
As of 235 PM Friday...

* Moderating temperatures to well above average by Tues with a cold
  front returning near normal temperatures for mid to late week.
* Sprinkles and very light rain accompany the frontal passage on
  Tues, with a better chance for wetting rain Thurs into Fri.

Early next week begins with low-amplitude mid/upper level flow over
a majority of the CONUS with an area of surface high pressure
centered near the FL/GA line. Through the day Sun, high pressure
will slip over the western Atlantic ahead of a developing trough
over the northern Plains. This trough will gradually deepen as it
traverses the Great Lakes and into the Northeast through Tues
evening. Cluster analysis suggest the greatest uncertainty with this
trough is the speed it translates eastward. Although central NC
largely remains removed from the better synoptic forcing, this will
have implications on the timing of mid-level cloud cover and light
rain, but mostly sprinkles, to move through the area. The most-
likely cluster from the 00z cluster analysis suggests a quicker
system is favored and would bring clouds and low rain chances to
most of the area before the early afternoon. This would mostly
impact high temperatures for the day as the overall rain amounts in
the 24 hours appear to be minimal (less than a tenth of an inch).

The system late in the week will have a better chance for widespread
precipitation, but the finer details will still need to be resolved
in the coming days. Both the depth of the trough and the timing of
its eastward progression result in a great deal of uncertainty. With
that said a period of active/wet weather appears likely sometime
between early Thurs and Fri evening. Most likely spread in total
rainfall (25th to 75th percentile among the grand ensemble) ranges
from 0.25 to around 1 inch across the area during the time.
Temperatures will climb to well above normal by Tues with a return
to near normal behind the fropa. Some degree of in-situ damming
appears possible as rain may begin to spread into the area by Thurs.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
As of 650 PM Friday...

Lingering 20 kt gusts this evening should cease within the next
couple hours with light surface winds steadily backing out of the
WSW overnight. Strong winds out of the NW at 2,000 ft will increase
to 40 to 50 kts and persist for a majority of the night at all TAF
sites and result in 35 to 45 kts of LLWS. Blacksburg`s radar (KFCX)
is already consistently sampling 35 to 50 kts at 2,000 ft with
around 60 kts around 2,500 ft. A shallow inversion will quickly mix
Sat morning with NW gusts increasing to around 25 kts shortly after
sunrise. Point soundings suggest infrequent gusts of 30 kts will
certainly be possible, especially at the Triad terminals Sat
morning. After sunrise, there is about 20 to 30% probability of an
MVFR cig developing from 14 to 17z (highest probability at GSO/INT)
before lifting to VFR by early afternoon.

Outlook: VFR conditions are expected through the beginning of next
week. A mostly dry cold front will move through the region on
Tuesday, bringing a northerly wind shift and a chance for sprinkles
falling out of mid-level cigs.

&&

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

&&

$$
SYNOPSIS...Green
NEAR TERM...Green
SHORT TERM...Green
LONG TERM...Swiggett
AVIATION...Swiggett/Helock