Area Forecast Discussion
Issued by NWS Memphis, TN
FXUS64 KMEG 251130
Area Forecast Discussion
National Weather Service Memphis TN
530 AM CST Sat Feb 25 2017
Updated for the 12Z Aviation Discussion
.PREV DISCUSSION... /issued 403 AM CST Sat Feb 25 2017/
A few storms developed across north MS Friday evening along the
cold front, but this boundary has moved well to the east of the
area. The drier and cooler post-frontal airmass will continue to
advect into the Mid-South today with northwest winds of 10-20 mph
this morning, decreasing to 10-15 mph by mid afternoon. Dewpoints
will fall into the upper teens and lower 20s today, resulting in
minimum relative humidity of 30-35%. These conditions are
marginal for elevated fire weather conditions which will
necessitate mention in the Fire Weather Planning Forecast. Expect
afternoon highs in the mid 40s to lower 50s this afternoon.
Winds will decrease rapidly around sunset as the surface
anticyclone builds into the region and the boundary layer
decouples. Dewpoints will remain quite low and skies will be
mostly clear, setting the stage for strong radiational cooling.
South winds are expected to resume over the western half of the
CWA by morning which may limit surface cooling. Regardless, many
areas will fall into the upper 20s and lower 30s. Some areas of
west TN and northeast MS will likely fall into the mid 20s, with a
few locations reaching the lower 20s, mainly throughout the
Tennessee River Valley. Sunday is shaping up to be a pretty nice
day with temperatures rebounding to near or just above seasonal
norms. Temperatures will be around 60 degrees south of I-40, but
increasing cloud cover over the northwest half of the CWA may
limit highs to the mid 50s farther north.
The flow aloft will be quasi-zonal on Sunday, but is forecast to
gradually back from a more west-southwesterly direction through
Tuesday as a progressive trough digs over the western CONUS. A
warm front will lift back north into the Mid-South Sunday night
into Monday, concomitant with a shortwave trough moving across the
region. A strong southwesterly low-level jet is progged to
develop, providing forcing for rain showers over the CWA. Very
little instability is anticipated at this time, mitigating the
potential for thunderstorms.
Though instability will increase on Monday, the initial shortwave
trough will be moving east and the surface boundary washes out.
This will limit rain chances to mainly the morning hours. The
latest model runs indicate that Monday afternoon could be mainly
dry across the area. Afternoon temperatures are forecast to be
primarily in the upper 50s to mid 60s. Temperatures aren`t
expected to cool significantly Monday night as warm, moist air
advects into the CWA. Rain chances will continue Monday night with
overnight lows in the mid/upper 50s.
Temperatures will warm into the 70s on Tuesday as southerly winds
increase to 15-20 mph. We`ll also see an increase in surface
instability with scattered showers and thunderstorms expected
throughout the day. Rain chances peak Tuesday night and Wednesday
as the main trough approaches from the west. Decent instability
and strong deep-layer shear will be present Tuesday night and
Wednesday. This may support organized strong to severe
thunderstorms across the region. CIPS analogs have been
highlighting this potential for the past few runs and we`ll
continue to monitor the evolution of this system.
The trough will move east of the area Wednesday night, bringing
rain chances to an end as a cold front moves across the Mid-South.
Cooler and dry weather is anticipated for the remainder of the
work week, with pleasant early March weather continuing into
Saturday. Low temperatures will fall back into the 30s by late
week with afternoon highs generally in mid 50s to mid 60s.
12Z TAF cycle
VFR conditions will continue for the entire forecast period. Winds
will be mainly from the northwest at 10 to 15 knots with higher
gusts through this afternoon before becoming light and variable