Area Forecast Discussion
Issued by NWS Columbia, SC

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS62 KCAE 201842
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
142 PM EST Mon Feb 20 2017

.SYNOPSIS...
Fair and warm conditions expect to continue through most of the day
Tuesday as high pressure shifts offshore ahead of an approaching
system, that will bring us a chance of showers mainly Tuesday night
and Wednesday, possibly into Thursday. A weak front will shift
through our region late Friday night into Saturday, with drier
air moving in for late Saturday and Sunday. Chance of showers
returns next Monday. Above normal temperatures expected through
the period.

&&

.NEAR TERM /THROUGH TONIGHT/...
Surface high pressure will ridge into the forecast area from the
north through tonight. The upper ridge axis will also be in the
area. The pattern supports limited low-level moisture through
tonight. Satellite trends indicate continued high cloudiness.
Nocturnal cooling may help support fog late tonight but it
should be limited by the dry air mass plus high cloudiness
limiting net radiational cooling. Also, the models indicate
some mixing should occur associated with a developing low-level
jet. The MAV and MET MOS plus SREF guidance were not indicative
of fog. Followed the NAM and GFS MOS for the wind forecast.
Expect light northeast to east wind. The temperature guidance
was consistent.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Upper and surface ridge will shift to our east late Tuesday as
upper low tracks east along the Gulf Coast. Increasing
isentropic lift and moisture transport could provide some light
shower activity, mainly CSRA and South Midlands, by late day or
evening, ahead of the main moisture plume that appears will
track east and affect the remainder of the FA Tue nt into Wed.
Upper and surface lows expected to track SE across the Eastern
Gulf of Mexico and towards South Florida Wed/Wed nt, with most
precipitation with that system staying mainly to our south,
although moisture lingers over our FA. Most guidance indicates
better rainfall coverage and amounts mainly to our north
enhanced by orographic lift and a weak in situ edge, though some
additional showers could develop in diurnal heating/differential
heating across the FA Wed aftn. With possibility of weak wedge
near the N FA, will cut down max temps a tad across that area
Wed.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Upper and surface lows progged to shift very slowly east in the
vicinity of S FL Thu/Thu nt. Weak in situ wedge may linger just
to our north Thu. A moist E to SE low level flow to provide a
continued chance of showers, enhanced by diurnal heating, Thu
aftn. However, by Thursday, some drier air aloft may move into
the region and cut down on overall shower chances. Forecasted
slight chance POPs for Thu. Some slight model differences in
timing of the closed low to our south eventually opening and
getting kicked out to the NE, but it appears to gradually do so
Fri/Fri nt, along with a surface boundary approaching from the
west. Models indicate nearly zonal flow across the southern tier
of states. Next disturbance to track ENE from the Rockies, with
it and the surface low staying to our north Fri nt/Sat, though
a weak impulse moves through our region. Next surface boundary
progged to track quickly across our FA late Fri nt/early Sat.
Chance pops appears ok with the front. Surface high pressure
and drier air will settle into our FA late Sat through Sun.
Modified Pacific air mass with cooler temps but still projected
to be above normal. Nearly zonal upper flow across the southern
states expected to continue late in the forecast period as
well, with systems moving rapidly. A quick moving trough will
track east across the country, with it and the surface low
staying to our north. Surface high to shift east ahead of it Sun
nt into Monday, with moisture return for our FA Mon/Mon nt into
early Tue. Chance POPs for that time period look ok for now.

&&

.AVIATION /19Z MONDAY THROUGH SATURDAY/...
Expect mainly VFR conditions through the TAF period.

Surface high pressure will ridge into the forecast area from the
north through tonight. The upper ridge axis will also be in the
area. The pattern supports limited low-level moisture through
tonight. Satellite trends indicate continued high cloudiness.
Nocturnal cooling may help support fog late tonight but it
should be limited by the dry air mass plus high cloudiness
limiting net radiational cooling. Also, the models indicate
some mixing should occur associated with a developing low-level
jet. The MAV and MET MOS plus SREF guidance were not indicative
of fog and we maintained VFR conditions. The models did not
indicate enough shear associated with the low-level jet for
inclusion in the terminal forecasts. Followed the NAM and GFS
MOS for the wind forecast. Expect light northeast to east wind.

The ridge at the surface and aloft will shift just off the coast
Tuesday. Low-level moisture should increase in an onshore flow.
The models also indicate isentropic lift. Believe stratocumulus
will develop especially at the southern terminals of AGS and
DNL where the models depict greater lift. Followed the MAV MOS
and forecasted a VFR ceiling developing at AGS and DNL.

EXTENDED AVIATION OUTLOOK....Moisture associated with an
onshore flow may help bring widespread MVFR or IFR conditions
through Friday.

&&

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

&&

$$


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.