104
FXUS62 KCAE 190554
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
154 AM EDT Sun May 19 2024

.SYNOPSIS...
Scattered showers with isolated thunderstorms move through
overnight as a cold front drops through the area. Abundant
moisture across the region will keep rain chances likely
lingering into Sunday, especially across the CSRA. Cooler and
drier air moves in for Monday and Tuesday with temperatures
rebounding during the middle of next week as another ridge moves
in from the west.

&&

.NEAR TERM /UNTIL 7 AM THIS MORNING/...
A line of showers and thunderstorms developed earlier this
evening across the northern Midlands. While convection has
waned, there remain isolated showers and even an embedded
thunderstorm or two. Maintained Chance PoPs across the northern
portion of the forecast area to account for recent radar trends.
Will need to monitor activity in the Upstate to see if it will
bleed into our forecast area, specifically the locations that
saw moderate to heavy rainfall earlier. Areas of low clouds and
fog are likely to develop towards daybreak, especially locations
that have seen rain tonight. Overnight lows will be in the
lower to mid 60s.

&&

.SHORT TERM /7 AM THIS MORNING THROUGH MONDAY NIGHT/...
Sunday and Sunday Night: Upper trough axis will swing through
the forecast area utilizing above normal PWATs which should
bring showers and isolated thunderstorms to the forecast area.
Expect scattered showers over the western Midlands Sunday
morning shifting southeastward through the day with a transition
to a more convective nature by early afternoon with some
surface heating. Hi-res CAM guidance in reasonable agreement
showing more widespread showers and thunderstorms across the
CSRA and southeast Midlands during the afternoon hours. Drier
and more stable air will move southward through the day so pops
will be decreasing from north to south through the afternoon
hours.

Abundant clouds and rain should limit temperatures tomorrow
with highs expected to range from the lower to mid 70s northern
Midlands to upper 70s to near 80 in the CSRA and southeast
Midlands. Clouds should begin to clear out from the north
overnight as drier air works into the region and some cool
advection will support overnight lows in the upper 50s to lower
60s.

Monday and Monday Night: High pressure will build over the
region with some rising 500mb heights in the wake of the
departing shortwave trough off the southeast coast. PWATs drop
to at or below an inch with forecast soundings showing a
subsidence inversion around 700mb and this should provide dry
and fair conditions. Temperatures should rebound a bit with
highs in the lower 80s under mostly sunny skies. Overnight lows
again expected in the upper 50s with reasonable radiational
cooling expected.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
Continued benign weather expected early in the extended
forecast period through mid week before some unsettled weather
returns by the weekend.

Ensemble guidance in fair agreement showing an amplified 500mb
pattern on Tuesday with a deep upper trough over the
intermountain west and off the southeast coast with an upper
ridge extending from the lower MS Valley through New England.
This upper ridge will build eastward over the forecast area by
Wednesday and although it weakens and flattens a bit on Thursday
due to a shortwave trough moving into southeastern Canada, the
ridge should still dominate over the southeastern states. At the
surface, high pressure centered off the New England coast will
ridge into the Carolinas and southeastern states Tuesday into
Wednesday and gradually shift eastward offshore by Thursday.
Ensemble mean PWATs are forecast to be below normal (around
70-80% of normal) Tue/Wed before PWAT values rise back above
normal on Thursday with the return deep southerly to
southwesterly flow as the surface high shifts further offshore.
This should result in a rain free forecast Tue/Wed followed by
low chances of convection returning by Thursday, mainly
diurnally driven.

Friday into Saturday, chances of rain increase as low pressure
lifts into southeast Canada pushing a cold front toward the
forecast area on Friday with ensembles showing sufficient
moisture (PWATs around 120% of normal) available and some weak
shortwave energy moving into the region. It is uncertain whether
or not the front will make it all the way into the forecast
area or not given it will be late May but nevertheless a
boundary in the area may still provide a focus for convection.
Temperatures during this period are expected to be near to above
normal with the upper ridging in place, warming through the
week.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
Monitoring for Restrictions Behind a Passing Frontal Boundary...

A backdoor cold front continues to move slowly south through the
northern Midlands tonight. Decreased ceilings are being noted at
stations behind this boundary and guidance remains bullish in
reduced ceilings reaching all terminals prior to daybreak. In
addition to these low clouds, area of fog are also possible,
especially at OGB and AGS. No significant changes were made to
the forecasts besides minor adjustments to the timing. Low
clouds will almost certainly last longer than guidance suggests
they will at this point, which is why this forecast keeps lower
MVFR at all sites through the end of the TAF period. Having said
that, some improvement is likely after 00Z Monday and a new line
will likely be added to the next forecast update to show this. A
few showers and perhaps a thunderstorm are possible at the
terminals later today, especially AGS/DNL. This potential has
been omitted from the TAFs for now due to low confidence but may
also be added with the next update if trends continue.

EXTENDED AVIATION OUTLOOK...Periodic restrictions from showers
and thunderstorms continue through Sunday evening. Conditions
should improve Sunday night followed by an extended period of
dry weather.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...None.
GA...None.

&&

$$