Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC-- Highlight Changed Discussion --
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FXUS62 KRAH 250326
Area Forecast Discussion
National Weather Service Raleigh NC
1026 PM EST Fri Feb 24 2017
A strong low pressure system will push through the Great Lakes
tonight. This will allow an associated cold front to cross our
region on Saturday. Cooler high pressure will build into the area
Saturday night and Sunday.
.NEAR TERM /TONIGHT/...
-- Changed Discussion --As of 1025 PM FRIDAY...
Mainly clear with a light SSEly breeze, and temperature mainly in
the 50s overnight.
A narrow ridge of surface high pressure remains over Ern NC this
evening, between a pre-frontal line of convection and closely
following cold front over central KY/TN,and a pair of surface lows a
few hundred miles off the coast of the Carolinas. The MSL pressure
gradient over mainly the Wrn half of NC will tighten late tonight,
as the aforementioned cold front nears the W slopes of the
Appalachians by 12Z. A light SSEly surface wind will consequently
gradually increase overnight, particularly W of I-95 (away from the
lingering narrow surface ridge axis). Associated modest radiational
cooling, with projected 12Z low level thickness values around 1375
meters, favor lows about a category below consensus guidance.
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.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
As of 342 PM FRIDAY...
Deepening cyclone will lift north into Ontario and Quebec, with
attendant trailing sfc cold front crossing the area Saturday
afternoon/evening. With the better dynamics and deeper moisture
lifting off to the north, accompanying band of convection will
weaken across North Carolinas, with only isolated to scattered
convection skirting across the northern tier.
Temperatures will approach record territory once again, especially
across the south-southeastern tier where it will remain mostly dry.
Highs ranging from mid 70s NW to lower 80s SE. It will be breezy as
well, with sustained winds of 15 to 18 kts, gusting to 25 to 30kts.
As far as severe potential: Steep low-level rates from the
unseasonably strong diurnal heating along with mid-level lapse rates
of 6.8 to 7.50 C/Km will result in weak destabilization of 500 to
1000 J/Kg across central NC. Given impressive 50 to 60kts of
unidirectional shear, it will be possible to see an isolated strong
to severe wind gust across the northern tier.
Strong post-frontal dry cold air advection Friday evening/night
will result in abrupt clearing and seasonable overnight lows
in the lower 30s NW to upper 30s/near 40 SE.
.LONG TERM /SUNDAY THROUGH FRIDAY/...
As of 205 PM Friday...
A broad upper level trough covering most of the contiguous U.S. will
result in a slightly unsettled weather pattern across the U.S. this
period. Temperatures, overall, are expected to remain above or well
above normal through mid-week. Afterwards, lower than normal heights
translates to near or slightly below normal temperatures for the
later half of the work week.
A series of upper disturbances will keep the atmosphere slightly
unsettled across central NC for the beginning of this period. High
pressure building into our region Sunday in the wake of an exiting
s/w and attendant sfc cold front will lead to drier cool conditions
Sunday. This high quickly scoots offshore Monday, leading to an
appreciable warm up with high temps expected to be about 8-10
degrees warmer than Sunday afternoon highs.
Models in general agreement lifting a mid-upper level across the
Deep South and the Southeast U.S. Monday night into Tuesday,
leading to a chance of showers. At this time, the highest threat for
rain across central NC appears to be late Monday night into early
Tuesday. A more amplified s/w will begin to affect our region
Wednesday with another chance for showers and possibly a few
thunderstorms late Wednesday into Wednesday night. This system exits
our region Thursday morning, leading to a more stable and cooler
Ahead of the mid week system, temperatures will once again average
10-20 degrees above normal with Wednesday`s high temps most likely
in the 75-80 degrees range. Cooler temperatures anticipated Thu-Fri
as a l/w trough develops over the eastern U.S.
.AVIATION /00Z Saturday through Wednesday/...
As of 805 PM Friday...
VFR conditions are likely to hold through much of tonight, and again
on Saturday, although a period of IFR conditions is possible at
RWI/FAY late tonight. The flat VFR cumulus that formed today with
heating has largely dissipated, although cigs persist in the
Sandhills including FAY. High thin clouds will continue to streak
across the area overnight, and in the eastern CWA, pockets of IFR
cigs are expected to form 08z-09z at RWI and 09z-10z at FAY, lasting
until 12z-13z. MVFR-IFR vsbys are possible at RWI during this period
as well. VFR conditions will then rule areawide 13z through the end
of the forecast period (00z Sun), however a band of showers and
storms will cross primarily the northern terminals (INT/GSO/RDU/RWI)
during the 16z-21z time frame, and this will likely bring a short
period of IFR vsbys and MVFR cigs as they pass through, along with
locally strong wind gusts. Outside of any showers/storms, winds will
be light under 7 kts from the SSW tonight, increasing from the SW on
Sat to 13-18 kts with periodic gusts of 20-30 kts expected. Winds
will veer to westerly just behind a cold front that will cross the
area immediately behind the showers/storms, during the afternoon
Looking beyond 00z Sun, skies will clear out by Sat evening with the
cold front passage and high pressure building in from the west for
Sat night through Sun, moving east and offshore Mon. The next chance
for sub-VFR conditions will be Mon night, lasting through Tue night
and perhaps into Wed, as southwest flow brings in low level moisture
and an increased risk for showers, as well low stratus and fog,
especially dusk through dawn. -GIH
Record highs for February 25:
Greensboro: 81 (1930)
Raleigh: 82 (1930)
Fayetteville: 85 (1930)