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117
FXUS62 KRAH 240554
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
155 AM EDT Fri May 24 2024

.SYNOPSIS...
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A warm and humid air mass over our region, combined with the passage
of a series of upper level disturbances over the area, will produce
unsettled weather through Monday, with daily chances of showers and
storms. A drier air mass will arrive by the middle of next week.
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&&

.NEAR TERM /THROUGH TONIGHT/...
As of 810 PM Thursday...

A series of convectively enhanced disturbances will traverse the
region tonight and again on Friday.

The first disturbance and associated convection tracked mainly
across northern portions of the Piedmont earlier this evening and in
the process of exiting the northern coastal plain counties. Areas
along and north of the 64 corridor have either been rain or out-flow
cooled from the earlier convection. Thus, the threat for severe
storms across the northern half of the forecast area looks to be
greatly diminished.

Trailing this lead vort, a secondary impulse is supporting an area
of showers and storms across the western Piedmont. The southern
portions of the Piedmont/south of 64, has yet to be worked over. So
could still a severe or two over the next hour or two before the BL
starts to cool from loss of heating.

Finally, a tertiary disturbance, the strongest of the bunch, is
starting to move into the southern Appalachians. The vort
disturbance is progged to cross the area between 06 to 15z Friday.
Further nocturnal stabilization should preclude any severe storms,
but will continue to support scattered to numerous showers, with
some embedded thunder overnight.

Lows tonight generally 65-70.

&&

.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
As of 200 PM Thursday...

Confidence for Friday continues to be low with inconsistency for
timing and coverage. An upper level shortwave is expected to move
across the region bringing plenty of moisture through out the
atmosphere with PW values around 1.60 inches, which is slightly
above the daily average. Marginal to moderate CAPE across much of
the region especially in the southern half of the CWA mixed with
temps in the mid/upper 80s and dew points in the upper 60s to low
70s could result in a few isolated to scattered storms developing
across the region in the afternoon and early evening. It is not
expected to be a complete wash out across the region but some storms
could become strong and slow moving. For now, keeping chance pops
this afternoon and continuing overnight for showers and isolated
storms, but again, confidence of this is low. Overall, some breaks
in the clouds during the first half of the day, increased cloud
coverage and chance of storms second half of the day and continuing
into overnight. High will range from mid 80s in the north to upper
80s in the south. Lows will generally be in the mid to upper 60s.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
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As of 155 AM Friday...

Best rain chance in this stretch will be Memorial Day into the
night. A pattern change should bring a dry period for mid to late
week.

Starting Sun, with the shortwave trough expected to be shifting well
off the Mid Atlantic coast early, we`ll be under the influence of
mid level shortwave ridging building in from the W, ahead of a
potent northern stream low/trough over MT into the Midwest. While
the weak surface trough will hold in place through the NC Piedmont,
there will be little opportunity for low level moisture influx until
late in the day into Sun night, and even this is more focused to our
W. The warm and relatively stable mid levels and lull in mid level
flow along with the limited moisture transport into the area should
greatly limit rain chances, and will keep late day and evening pops
mainly in the far NW to account for any mountain convection spilling
toward our area. It`ll remain warm and humid for this time of year,
highs in the upper 80s-lower 90s and lows in the upper 60s/lower 70s.

Rain chances may increase late Sun night with an upturn in low level
moisture and greater PW spreading in ahead of a pronounced low to
mid level trough that will move in from the W, attending an
approaching surface cold front. Winds at all levels will strengthen,
including a low level pump from the Gulf that starts ramping up Sun
night. The improving kinematics and vorticity maxima moving through
the mean trough base across our area in tandem with this
increasingly deep moisture should prompt high rain chances. The
severe threat with any storms is tough to pin down, as an early
arrival of frontal showers and clouds will hold down SBCAPE,
although the incoming cooling aloft and rising low and mid level
lapse rates should still allow for a risk of a few strong storms.
Still warm and muggy with highs in the upper 80s-lower 90s. Lower
dewpoints should start to filter into the NW Mon night, so expect
slightly lower lows there, mid 60s with upper 60s to around 70
across the S and E.

Behind this front, as mid-upper level longwave troughing sets up
over E NOAM with low level CAA and drying through the column, we
should see largely dry weather Tue through Thu. Some deterministic
models do slow down the cold front such that a passing wave produces
convection chances across the S and E Tue, so will leave in a low
chance there. Otherwise, will have dry conditions through Thu with
temps running close to normal. -GIH
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&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
As of 742 PM Thursday...

24 hour TAF period: Forecast is tricky and somewhat low confidence
over the next 24 hours. The two primary concerns are: 1. the
possibility for continued convection and 2. the potential fog/low
stratus development where rain has occurred today. Some guidance has
multiple rounds of convection moving through central NC tonight into
the day Fri, however there is uncertainty whether that will persist
with loss of heating and some stabilization from convection earlier
this aft/eve. Outflow from the storms has met up with a lingering
surface boundary roughly W-E across the area, south of KRDU and
KRWI. Highest confidence of showers/storms tonight along and south
of that boundary. As for fog/low stratus tonight, there is a good
signal in the guidance for development where convection has
occurred, so that would be every site aside from KFAY as of 00Z.
However, showers/storms are expected to move through KFAY in the
coming hours, so there is a chance there as well. Have tried to add
all that to the TAF, however timing and extent may be a little off.

A return to VFR conditions is expected through the morn/aft from
west to east, but again that depends on development of sub-VFR
conditions in the first place. Otherwise, winds should generally be
calm to light and variable, with stronger winds/gusts with storms
where they occur.

Looking ahead: Primarily diurnally driven showers/storms will be
possible at all terminals through Tue, with the best chances Fri,
Sat, and Mon.

&&

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

&&

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