Area Forecast Discussion Issued by NWS Raleigh/Durham, NC
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000
FXUS62 KRAH 151533
AFDRAH
Area Forecast Discussion
National Weather Service Raleigh NC
1133 AM EDT Fri Mar 15 2024
.SYNOPSIS...
Warm high pressure centered offshore will extend west across the
Southeast states today. A weak cold front will drop into the region
tonight, then stall out and hold over the Carolinas over the
weekend. A stronger cold front will cross the region late Sunday,
bringing cooler air for the beginning of next week, including a
frost and freeze potential Monday night.
&&
.NEAR TERM /TODAY THROUGH TONIGHT/...
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As of 1130 AM Friday...
Water vapor imagery continues to show a quasi-stationary upper low
spinning over the Desert Southwest, with a shortwave trough diving
south into the Northern Plains and Upper Great Lakes. These features
are helping to push the ridging that had been over the Southeast US
into the western Atlantic. At the surface, a low pressure system is
moving east over southern New England, with a cold front draped to
its southwest from the northern Mid-Atlantic into the TN and lower
MS Valleys. Along and ahead of this front, a widespread area of
convection continues to push east, with some lightning being
observed over the western Carolinas. These showers and storms are
about to move into the western Piedmont and will push east across
the rest of central NC through this afternoon. However, given they
are already on our doorstep and widespread clouds are beginning to
move in, we will have very little time to destabilize. Current dew
points are only in the mid-40s to about 50, and SPC mesoanalysis
shows no MLCAPE or effective shear. So only expecting a slight
chance of storms at best today, mainly across the south, and not
concerned about a severe threat. There will be decent moisture
transport given the deep WSW flow in both the upper and lower
levels, but the upper forcing will be weak as the best is displaced
well to our NW. Given these factors and what the CAMS continue to
show, expect the band of showers to gradually diminish in intensity
as it moves east across our region, clearing the Coastal Plain by
00z.
After a lull in precipitation this evening, a few light showers may
redevelop across the south and east after midnight as the cold front
moves through and taps into a more moist airmass by that point, with
dew points in the upper-50s to lower-60s. A rumble of thunder can`t
be ruled out, but given the timing, instability will still be
minimal, and the 12z CAMS are even drier overall than before. Total
amounts today and tonight are only expected to range from a tenth to
a quarter of an inch on average.
As for temperatures, lowered them slightly for today given the
overcast skies already moving into the west. Expect highs to range
from lower-70s around the Triad to lower-80s in the eastern
Sandhills and Coastal Plain. This is still well above normal for
this time of year thanks to the SW winds ahead of the front (gusting
up to 15-25 mph this afternoon). The cloudiness will keep tonight`s
lows quite mild as well, in the 50s.-- End Changed Discussion --
&&
.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
As of 329 AM Friday...
Friday`s cold front will stall along the coast Saturday promoting
dry conditions over central NC. Flow will turn more nely behind the
front early Saturday promoting stratocu into the afternoon period.
While temps will cool off a bit on Saturday, the airmass will
moderate a bit in the afternoon supporting highs in the lower 70s.
Overnight lows will dip into the lower 50s.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 235 AM Friday...
Apart from a shot of rain chances in our S/SE late Sun-Sun night,
we`ll likely stay dry through Thu, with warm weekend temps falling
below normal early in the week before trending back toward normal
mid week.
Sun/Sun night: Mid level flow will be zonal across the east-central
CONUS early Sun, as a polar low sit over the Ontario/Quebec border
and another low holds over AZ. Our steering flow will back to SW as
energy digs down into the polar trough, through the Upper
Midwest/Great Lakes region into the Ohio Valley through Sun night. A
much weaker perturbation through the southern stream will cross the
Southeast states late Sun into Sun night, ahead of the incoming
surface polar cold front. Models all depict an area of showers ahead
of the front streaking across SE NC, with spatial variations
regarding the primary swath of rain. Based on the LREF/NBM, much of
the heavier precip appears poised to sneak by just to our SE with
lower pops primarily covering just our SE 2/3rds, although the
outlier NAM is much further NW with heavier rain well into our area.
Will favor these further-SE ensemble output solutions, spreading low
chance pops across much of our SE but with low QPF overall, focusing
on late Sun through Sun night, ending prior to daybreak Mon. Expect
highs in the 70s followed by lows in the 40s to lower 50s.
Mon-Tue: The potent mid-upper shortwave trough just N of the Ohio
Valley early Mon will continue to drop SE, swinging through NC late
Mon through Mon night. This will draw a reinforcing secondary cold
front through our area Mon and bring the coldest air of this mini-
respite, along with stout/gusty winds. We should see a shot of
enhanced cloud cover just ahead of the incoming vorticity max,
although if it is sufficiently strong with a far-southward track
across the Carolinas, we could see enough lift/condensation late Mon
for a few sprinkles over the E and SE where the low levels will be a
bit more moist ahead of the secondary front. But, at this point, the
risk of anything substantial appears low, and will keep Mon dry. A
surge of Canadian air will peak late Mon night into Tue morning,
when our greatest chance for near- or sub-freezing temps will occur,
before the incoming high across the Deep South quickly moderates,
although as winds diminish Tue night, the greater radiational
cooling potential could make that a second near-freezing night in
some spots. Will have mid 50s to mid 60s for highs Mon, then lows
from around 30 to the mid 30s Mon night, which may include some
upper 20s in the typically colder spots. Tue highs will be our
coldest day and well below normal, in the 50s, followed by lows in
the 30s. Frost/freeze alerts will likely be needed, esp over
portions of the Piedmont and northern Coastal Plain, Mon night, and
perhaps again Tue night, albeit with a lower threat area.
Wed-Thu: Air mass moderation persists but with increasing model
spread in the details. Additional energy will dive SE through the
Northeast states (and possibly as far S as the Mid Atlantic coast,
if the Canadian model is to be believed) on Wed, as we maintain a
dry northwesterly steering flow into NC. This flow will back and
slow down by Thu as flat but amplifying shortwave ridging builds
into the Southeast states, ahead of a progressive shortwave low and
trough through the south central CONUS. The Canadian is slower than
the GFS/ECMWF with this feature, a result of its stronger/slower
polar stream mid week, so will favor the GFS/ECMWF solutions with a
solution suggesting greater incoming ridging aloft and greater
warming but with cirrus overspreading our area ahead of likely
convection Thu from the TX coast into the lower Miss Valley. Highs
will have rebounded in the 60s to around 70 both days. -GIH
&&
.AVIATION /10 FRIDAY THROUGH TUESDAY/...
As of 619 AM Friday...
VFR conditions continue this morning as high pressure remains
anchored just offshore. Scattered cirrus continue to spill across
central NC from upstream convection over the TN/OH valley. Expect
mid to high level cloudiness to thicken from west to east later this
morning/afternoon as showers approach the area. Showers and
possibly an isolated storm should generally diminish with eastward
extent this afternoon/evening, but can`t rule out at least some
brief potential for associated sub-VFR conditions to develop at
times (highest probability at KINT/KGSO). Otherwise, LLWS will
continue at northern terminals through about ~14Z. Beyond ~14Z, good
mixing should support swly gusts of 15 to 25 kts through early this
evening.
A period of post-frontal MVFR ceilings appears likely to form at
eastern TAF sites (KFAY/KRWI) early Saturday morning. Elsewhere,
should remain VFR.
Outlook: Any lingering MVFR ceilings early Saturday should lift with
time as dry conditions return to our area. Additional showers and
sub-VFR conditions will be possible Sunday night into Monday. VFR
conditions will return Monday into Tuesday.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Hartfield
NEAR TERM...Danco
SHORT TERM...Luchetti
LONG TERM...Hartfield
AVIATION...Luchetti