Area Forecast Discussion Issued by NWS Raleigh/Durham, NC
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FXUS62 KRAH 170756
AFDRAH
Area Forecast Discussion
National Weather Service Raleigh NC
352 AM EDT Sun Mar 17 2024
.SYNOPSIS...
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A cold front will cross the region late Sunday, bringing cooler air
for the beginning of next week, including freeze potential Monday
night.-- End Changed Discussion --
&&
.NEAR TERM /TODAY THROUGH TONIGHT/...
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As of 352 AM Sunday...
Zonal flow over central NC was evident on water vapor imagery this
morning. Further north, an upper trough was digging into the upper
Midwest. Simultaneously, weak vorticity perturbations embedded
within a developing shortwave have generated convection from central
TX northeastward through AR.
At the sfc, a weak area of low pressure was located near Cape
Lookout, with a boundary extending just offshore and south through
the Gulf of Mexico. Further northeast, a 1014 mb high anchored off
Cape Cod was extending light ssely flow across central NC ahead of a
cold front draped across the Ohio Valley. Residual stratus will
quickly lift this morning, but additional mid to level cloudiness
will blanket the sky as the aforementioned shortwave over the deep
south moves through the southeast today. Highs will remain a bit
above average again today in the upper 60s to lower 70s.
A sfc low associated with the shortwave over TX this morning will
push east across the Gulf of Mexico today and scoot by just to our
south overnight. Rain chances for our area appear to be quite low
today given that 1) the deeper moisture will pool to our south and
2) the better upper and sfc forcing will remain well to our north.
Still can`t rule out a few passing showers across the Sandhills and
Coastal Plain, but overall expecting a low QPF event.
The cold front currently over the Ohio Valley will pass through our
area tonight. Swly flow ahead of the cold front may induce some
gusts of 10 to 20 mph this afternoon/evening. Additionally, good
mixing behind the front will likely support periods of nwly
gustiness with frontal passage through early Monday morning. CAA
should lag the front, allowing overnight lows to remain in the lower
50s.-- End Changed Discussion --
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.SHORT TERM /MONDAY AND MONDAY NIGHT/...
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As of 352 AM Sunday...
Deep mixing behind Sunday night`s cold front should allow for gusty
nwly sfc flow (15 to 25 mph at times) and considerably drier air to
move across central NC Monday. Strong CAA and periods of cloudiness
will limit daytime heating as high temperatures struggle to reach
the mid to upper 50s.
Aloft, a strong upper trough will move over our area Monday night
into Tuesday morning. Forecast soundings indicate additional
stronger gusts and CAA may accompany it`s passage promoting chilly
overnight lows upper 20s to mid 30s. Given that the growing season
has officially began for our southern Piedmont locations, decided to
issue a Freeze Watch for Stanly, Montgomery, Lee, Anson, and
Richmond counties. Probabilities for sub-freezing temperatures in
these counties amongst varying ensembles are high enough to
necessitate the watch. Regardless of your location and associated
official growing season start dates, make sure to protect any
sensitive vegetation Monday night. Lastly, a few sprinkles or
isolated showers may accompany the passing of the upper trough early
Tuesday morning.-- End Changed Discussion --
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.LONG TERM /TUESDAY THROUGH SATURDAY/...
As of 320 AM Sunday...
Overview: Cool and dry early-week weather will rebound back closer
to normal temps by mid to late week. The late-week rain chances that
appeared fairly certain yesterday are now much less clear, with
recent models exhibiting varied solutions in terms of sensible
weather, leading to lower-than-usual confidence for Thu-Sat.
Tue-Wed: The potent mid level shortwave trough will have shifted
offshore by Tue morning, although another much weaker perturbation
will shift ESE through NC Tue afternoon. Our dry NW steering flow
will then slow and back gradually through Wed night, while the
persistent closed low over AZ finally opens a bit and tracks E
through NM to OK/N TX. At the surface, our incoming chilly high
initially centered over E TX will expand eastward across the Deep
South/N Gulf/FL through Wed, while moderating, as noted in model
forecast low level thicknesses which improve from about 50 m below
normal Tue morning to just 10 m below normal Wed morning. After a
frigid start Tue, temps should peak around 10 deg below normal, in
the 50s, despite plenty of sunshine. Fair skies and light winds with
decoupling Tue night should yield good radiational cooling, but
guidance still suggests that only outlying/rural areas of the
Piedmont and W Sandhills have a risk of near-freezing temps, while
the majority of central NC will see lows in the mid 30s to around
40. Expect a seasonably mild Wed with highs in the mid 60s to lower
70s under mostly sunny skies. Operational models and the LREF do
bring an Arctic cold front in backdoor fashion SSE into or through
NC Wed night, driven by a passing shortwave trough through the
Northeast states and incoming dense air associated with a cold high
pushing from Manitoba/W Ontario into the Upper Midwest/Great Lakes.
Thus, our temps should drop back below normal Wed night, esp across
the N, with lows from the mid 30s near the VA border to the low-mid
40s S.
Thu-Sat: Forecast confidence declines late in the week. As the
Arctic trough lifts NE into the Canadian Maritimes, with a portion
of the high to our north shifting over and off the Mid Atlantic
coast, we`ll be left primarily under the influence of the southern
stream, with our forecast hinging on the mid-upper shortwave trough
tracking from OK/N TX across the Gulf states and to the Southeast
coast through this period. Over the last 24-36 hrs, the ECMWF/ENS
and the EC-based ML models have trended toward significant dampening
of this wave as it moves into the Gulf states and Southeast, such
that they are largely dry for NC during this period, with only the
GraphCast ML model with light precip in S NC while the ECMWF/ENS and
other ML models keep us dry, except near and off the Carolina coast.
The GFS/GEFS/Canadian/GEPS, meanwhile maintains a sufficiently
robust shortwave trough moving through the Gulf/Southeast states and
off the Southeast coast during this period with rain chances
spreading over the Carolinas due to the increasing long fetch of
Atlantic moisture spreading NW into NC. With these latter model
clusters along with the NBM output still depicting rain chances, esp
over our SE, from late Thu night into Sat (peaking Fri/Fri night),
will maintain pops during this time frame but hold them at chance,
modestly above climatology. Expect near normal temps Thu with
increasing clouds, then slightly below normal Fri/Sat with mostly
cloudy skies and rain chances. -GIH
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
As of 148 AM Sunday...
Periods of MVFR to IFR stratus will continue KRDU, KFAY, and KRWI
through early to mid morning. Additionally, some reduced
visibilities via fog will be possible at KFAY/KRWI between ~6 and
10Z. Conditions at these terminals should lift to VFR by early to
mid-morning. Otherwise, swly sfc flow will pick up a bit in the
afternoon gusting to 10 to 20 kts at times. Mid to high level
cloudiness will increase ahead of an approaching cold front which
will pass through the area later tonight. A few showers may scoot
by late in the TAF period, but overall expect mostly dry conditions
today and tonight.
Outlook: Another cold front will clear the area Sunday night into
Monday, behind which, gusty nwly flow will develop Monday. VFR
conditions are then expected through the remainder of the outlook
period.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Kren/Luchetti
NEAR TERM...Luchetti
SHORT TERM...Luchetti
LONG TERM...Hartfield
AVIATION...Luchetti