Apex, North Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

422
FXUS62 KRAH 040800
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
300 AM EST Wed Dec 4 2024

.SYNOPSIS...
Arctic high pressure over the region will move offshore this
afternoon, with onset of southerly return flow allowing a brief warm-
up before a reinforcing arctic front crosses the region
Thursday.

&&

.NEAR TERM /TODAY AND TONIGHT/...
As of 300 AM Wednesday...

Reloading of the upper trough gets well underway as a deep upper low
and associated upper trough swing southeast through the Upper
Midwest, Upper Great Lakes, and Ohio Valley through tonight. Under
quasi-zonal flow aloft, heights will steadily decrease with 30-50
meter height falls overspreading the area tonight. At the surface,
Arctic high pressure will move off the SE US coast during the
afternoon, ahead of a cold front that will be on our western
doorstep by daybreak Thursday.


Despite the synoptic forcing moving into the area, the lack of
substantial moisture transport into the area will result little in
the way of cloudiness with mostly sunny/clear skies prevailing.

Onset of southerly winds will result in a modest moderation of the
cA in place. Highs ranging from mid 40s north to near 50 south.
Winds will gradually increase with gustiness developing as a 40-50kt
LLJ overspreads the area during the late afternoon and into the
overnight hours. A well mixed BL with steady SSWLY winds of 10 to 20
mph will keep temps up overnight. Not as cold with lows in the lower
to mid 30s.


&&

.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
As of 300 AM Wednesday...

...Reinforcement of Arctic Air Thursday Night...

...Wind chills in the single digits to lower teens at the bus stop
Friday morning...

The upper trough will move through the region in clipper fashion and
will propel a dry, reinforcing Arctic cold front through the area
during the morning and early afternoon hours. Frequent pre and post
frontal gustiness of 25 to 35 mph is expected through the afternoon
the early evening, before subsiding Thursday night.

The NW to SE timing of the frontal passage will govern daytime highs
and will feature a sharp temperature gradient across the area. Highs
ranging from mid 40s north to upper 50s/near 60 across the SE.
Strong CAA Thursday night will bring very cold temps and low wind
chills. Lows in the mid/upper teens to lower 20s, with wind chills
in the single digits to lower teens.

 &&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
As of 230 PM Tuesday...

Broad northwesterly flow aloft will continue Friday through the
weekend, eventually veering and becoming southwesterly on Sunday. At
the surface, a sprawling 1030+mb high will position itself over the
Ohio Valley on Friday and off the NC coast Sunday. Friday will be
quite chilly with highs in the upper 30s to lower 40s, gradually
moderating into the mid 40s and mid 50s Saturday and Sunday
respectively. Lows will follow a similar trend, with teens Friday
night, mid 20s Saturday night, and upper 30s Sunday night.

There is general ensemble agreement in a southern stream trough
developing on Sunday with mid level moisture and forcing for ascent
overspreading the area early next week. Unfortunately, there remain
differences with respect to the trajectory that this trough will
take, with some scenarios taking the trough northward into the Great
Lakes with minimal precip across NC, while others take a more
southern track with more widespread rainfall. I will maintain NBM
PoPs in the 40-50 percent range Monday into Tuesday, but this
remains a low confidence portion of the forecast. At this point it
looks like temps should be sufficiently warm for an all-liquid
precip forecast, given antecedent surface high pressure migrating
offshore (southeasterly surface winds) vs holding strong over
eastern Canada (northeasterly surface winds).

&&

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

TAF period: High confidence in VFR conditions through the TAF
period. Light and variable winds will become SWLY after daybreak and
will increase with gusts of 15-20 kt by the afternoon. SWLY Winds
will stay up Wednesday night, with some intermittent gustiness as a
strong ~45-50kt LLJ overspreads the area, resulting in LLWS at all
TAF sites.

Outlook: Gusty conditions will continue on Thursday, ahead of a dry
cold frontal passage, with a period of NWLY post frontal gustiness
Thursday evening/night. Otherwise, VFR conditions should continue
through the weekend.

&&

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

&&

$$

SYNOPSIS...CBL
NEAR TERM...CBL
SHORT TERM...CBL
LONG TERM...Leins
AVIATION...CBL