Turner Downs Forecast Discussion

000
FXUS62 KRAH 010735
AFDRAH

AREA FORECAST DISCUSSION
National Weather Service Raleigh NC
335 AM EDT Wed Apr 01 2020

.SYNOPSIS...
Strengthening low pressure will drift slowly away from the North
Carolina coast this morning, bringing a cool northerly flow into the
area. The low will meander over the northwest Atlantic just off the
Mid Atlantic and Northeast coast through Saturday, as deep high
pressure extends over the eastern United States.

&&

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

The surface low is analyzed just off Cape Hatteras at this hour,
with the solid area of steady rain shifting slowly E out of the
forecast area, accompanied by the upper divergence max and area of
greatest mid level DPVA. Spotty light showers persist over the E
Sandhills as well as over the far NW Piedmont and adjacent VA,
within a band of low level confluent flow and a weak vorticity max
dropping into the SE side of the mean mid level low. This shower
risk appears poised to continue and even increase a bit later this
morning into early/mid afternoon over the NW Piedmont, with models
showing high moisture persisting in the lowest 2 km along with a
steepening of low level lapse rates, in conjunction with continued
low level moisture convergence, over the W Piedmont into this
afternoon. Several CAMs also indicate a N-S band of showers
extending down into the Triad later this morning before shifting
slowly E through central NC and gradually diminishing this
afternoon. After trending the low chance pops downward early this
morning as the low departs, will include a band of isolated to
scattered showers over the N and W Piedmont for a few hours late
this morning into mid afternoon to account for this deep low level
moisture and lingering confluent band. Otherwise, expect the thick
low clouds to gradually break apart today as drier air aloft works
into the area, with skies becoming generally clear by nightfall.
Confidence in high temps today is low, with CAA and the potential
for some areas to be overcast well into the afternoon. Will have
highs in the mid 50s to near 60, assuming at least some insolation
but with thicknesses running 25 m or more below normal. Gusty winds
mainly from the N today are likely to gust to 20-30 mph but should
diminish later this afternoon as the MSLP gradient starts to relax.
Decreasing winds and clear skies overnight should facilitate enough
radiational cooling for temps to bottom out in the upper 30s to
lower 40s. -GIH

&&

.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
As of 325 AM Wednesday...

Expect lots of sunshine but cool temps as CAA persists around the
deep circulation off the Northeast coast. The temporary blocking
pattern consisting of ridging between the NW Atlantic low and a low
over the Canadian Prairies will lead to a dry and subsiding column,
albeit with modest height rises over central NC. Despite the CAA and
low level thicknesses projected to be 20-25 m below normal, the
strong early-April sun should allow temps to warm up through the day
to highs in the low-mid 60s, about 1-2 categories below normal, with
another round of gusty winds from the NW. Expect another cool night
Thu night with diminishing winds and clear skies. Lows should again
be in the upper 30s to lower 40s. -GIH

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 330 AM Wednesday...


Coastal low off the New England Coast will wobble slowly out to sea
through Saturday. This will allow surface high pressure to our west
to take control, and will maintain dry, below normal conditions
through at least Saturday. Highs 65 to 70, with morning lows
generally in the 40s.

Sfc high pressure will shift offshore early Sunday. Corresponding
return flow will boost temps to near normal on Sunday. Models
indicate a weak front will move east and stall out across the area
late Sunday and Sunday night. Limited moisture owing to deep W-NWLY
flow preceding the front, coupled with very weak instability will
greatly limit precip chances with the front. Thus, have kept PoPs in
the isolated/slight chance ranges.

The front is forecast to either wash out across the area or lift
north as a warm front on Monday, which will result in further lower
tropospheric warming with highs climbing into the upper 70s to near
80 by Tuesday. More substantial rain chances may arrive Tuesday and
into Wednesday with the arrival of shortwave impulses and related
low to mid-level warm moist air advection spilling over the
shortwave ridge.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
As of 155 AM Wednesday...

Poor aviation conditions, mainly high-end IFR to low-end MVFR, will
persist through this morning, with blustery winds from the N and
patchy light rain. A strong surface low currently just off the S
Outer Banks will continue a slow drift to the NE through this
morning, taking with it last evening`s widespread rain, although the
moist northerly flow around the low will keep the low clouds over
the area with patches of light rain and drizzle through mid morning.
A gradual lifting of cigs through the MVFR category to low-end VFR
is expected to occur late morning through lunchtime at all sites,
although a brief sprinkle remains possible mainly at INT/GSO during
this time. Cigs should clear by 21z-23z and remain generally clear
through the end of the TAF valid period. Winds will remain brisk
from the N (ranging from NNE to NNW direction), sustained 8-13 kts
gusting to 18-28 kts through much of the afternoon, then will
diminish to under 10 kts after 21z.

Looking beyond 06z Thu, VFR conditions are likely tonight through
much of Sun, as high pressure will be in control, although there is
a small chance for MVFR cigs with showers near INT/GSO late Sun.-GIH

&&

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

&&

$$
SYNOPSIS...Hartfield
NEAR TERM...Hartfield
SHORT TERM...Hartfield
LONG TERM...CBL
AVIATION...Hartfield

NWS RAH Office Area Forecast Discussion