Area Forecast Discussion
Issued by NWS Charleston, SC

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FXUS62 KCHS 232352

Area Forecast Discussion
National Weather Service Charleston SC
752 PM EDT Mon May 23 2022

Warm and humid conditions along with a few smaller scale
systems moving through, will maintain unsettled weather across
the area through much of the week. Drier conditions could then
return this weekend.


This Evening and Tonight: An area of low pressure will continue to
shift north-northeast across northern Georgia and eventually into
the South Carolina Upstate and western North Carolina while much of
the local area remains along the edge of high pressure centered
across the western Atlantic. Low-lvl convergence extending well
southeast of the low pressure center will continue to support
showers and thunderstorms shifting across the area through
early evening hours. Latest radar indicates a congealed line of
showers/thunderstorms just east of the I-95 corridor displaying
a weakening trend, mainly outflow dominant heading northeast
toward the coast. Although there is a risk of an isolated
strong wind for the next hour or two across the Tri-County Area,
the environment is becoming less conducive for severe weather
due to the loss of peak diurnal heating. For this reason, shower
and thunderstorm intensity/coverage should continue on a
downward trend heading into sunset, followed by a further
weakening/dissipating trend through late evening hours due to a
worked over environment. By midnight, dry conditions should
prevail across most areas. Despite cloud cover, ample moisture
from recent rains and favorable condensation pressure deficits
suggest the potential for some patchy fog inland. Low temps
should remain mild, generally ranging in the upper 60s to lower


Pattern Synopsis/Forecast: Strong Pacific short-wave energy will dig
into the southern and central Plains heading into midweek, with a
mid-level low closing off along the the front range of the Rockies
Tuesday before slowly progressing into the Plains. System is a bit
stronger, deeper and slower than in previous guidance forecasts.
Downstream, upper level ridging will hold along the SE states into
the Atlantic through the short-term period with warm and modestly
moist conditions persisting across the region.

Convective evolution and precip chances remain the main forecast
challenge through the short-term. After today`s round of convection
wanes later tonight, appears we will start the day Tuesday rain-
free, probably through the morning hours. Ample low level moisture
and daytime heating will drive MLCAPE values into the 1-2K J/Kg
range for the afternoon. Recent high-res CAM guidance along with the
NAM/GFS continue to suggest we see another round of thunderstorm
development later in afternoon into the evening, possibly along any
residual outflows from todays storms as well as sea breeze
interactions. But unlike today, flow aloft/shear profiles will be a
bit weaker owing to the departure of the Gulf low. No doubt there
will be some strong storms to monitor, but an organized severe
weather threat looks lower than today. Still quite a bit of
uncertainty regarding the timing and coverage, and thus I will
maintain just chancy pops for now.

Wednesday and Thursday may quiet down some. But with the warm and
somewhat humid conditions remaining, we will have to maintain some
chances for showers and storms for the afternoon into the evening.

Temperatures through the period will remain at or a little above
normal for late May.


Closed upper level low will be slowly migrating through the SE CONUS
and Gulf Coast region through most of the extended period, pressing
a boundary into the region late Friday into Saturday. But, as is
typically the case with these closed upper lows, timing is
problematic (slower is usually better and guidance is already slower
today compared to yesterday). Right now, highest rain chances will
come with the front later Friday/Friday night, with a potential
drying trend heading into the weekend and early next week. Will see
how that goes and adjust as we go along. Temperatures through the
period will remain around normal.


Tempo MVFR conditions remain in place at all terminals due to
showers and/or thunderstorms between 00-01Z this evening. VFR
conditions should then prevail overnight through much of
Tuesday. However, latest guidance suggests the potential for
a round of MVFR cigs a few hours before daybreak, then potentially
with afternoon showers and thunderstorms Tuesday afternoon.
Confidence remains too low to include in the terminals for the
00Z TAF issuance.

Extended Aviation Outlook: VFR conditions will largely prevail
throughout the week. However, flight restrictions remain possible at
times at the terminals, as periodic showers and thunderstorms impact
the region during the afternoon into the evening. A touch of fog is
also possible each morning as well.


This Evening and Tonight: Outside showers/thunderstorms that
shift offshore this evening, southerly winds will prevail with
speeds mostly in the 10-15 kt range or less during the overnight
period. However, some enhancement remains along the land/sea
interface this evening, with gusts around 20 kt at times. Seas
will range between 2-3 ft through the period.

Tuesday through Saturday: Conditions will remain below Small Craft
Advisory levels through midweek, although locally higher winds and
waves will occur with any storms that move through the coastal
waters. A bit stronger south to southeasterly flow along with higher
seas develop through the coastal waters late in the week as a strong
cold front approaches from the west. However, at this juncture,
winds and seas are still expected to remain below headline





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