Forecast Discussion

FXUS64 KMEG 191605

Area Forecast Discussion
National Weather Service Memphis TN
1005 AM CST Fri Jan 19 2018


High pressure remains centered over Alabama this morning.
Southerly winds on the back side of the high have already warmed
temperatures into the 30s across the Mid-South. However looking
at the latest satellite images, a large area of clouds between
4000-5000 FT are pushing into portions of Eastern Arkansas and
Northwest Mississippi. The RAP shows these clouds spreading as far
north as I-40 and as far east as the Alabama line. Will adjust
the sky conditions accordingly. In addition, have lowered highs
slightly in locations that still have a lot of snow pack and that
will be impacted by the cloud cover. Update will be out shortly.



.DISCUSSION... /issued 301 AM CST Fri Jan 19 2018/

Temperatures are in the low to middle 20s across most of the
Midsouth, likely cooling another 2-4 degrees by sunrise. We should
see plenty of sunshine today. Temperatures will warm quickly,
with moist of the region above freezing before midday.
Temperatures will remain above freezing for several days. Highs
will be in the 40s...still a little below normal at most
locations, but much warmer than we have endured for most of 2018.

Clouds will return to the Midsouth tonight as a low latitude
trough tracks along the Gulf Coast. Farther West a low will deepen
over the 4 corners area resulting in the development of strong
Southwest flow across the Midsouth late Saturday into early
Sunday. Cloud cover will likely keep temperatures in check a bit
Saturday...undercut guidance temperatures a bit over the weekend.
We will see several days of southerly flow ahead of the next
storm system. Dew points may surge into the middle 50s by midday
Sunday as a deep trough shifts into the Plains. Late Sunday into
early Monday, this feature and its associated cold front at the
surface will shift across the Midsouth. With dew points only in
the mid 50s, instability is expected to be limited. However
guidance indicates favorable diffluence aloft, a 125kt Jet and a
50-60 kt LLJ will result in the potential for some strong storms.
This actually may be too much shear for storms to sustain healthy
updrafts. Will maintain a low confidence of strong storms in the
HWO for now. It wouldn`t take much...slightly higher dew points
and or slightly warmer create conditions much
more supportive of severe thunderstorms. A little less shear would
likely increase the severe potential as well resulting in a more
healthy balance of instability and sheer. For now we are only
expecting a weakening line of showers and isolated thunderstorms
moving quickly across the area early Monday. The ECMWF is a little
slower than the GFS. This solution could help the system take
advantage of daytime heating early Monday.

Above normal temperatures are expected over the weekend into early
next week. The warmest day should be Sunday. It will only be
slightly cooler Tuesday through midweek as the airmass behind the
front is of Pacific origin instead of Arctic. Expect near to
slightly above normal temperatures for the Middle and later part
of the work week. A few showers may return by Friday.




12z TAFs

VFR conditions prevail for the TAF set, possibly reaching MVFR
cigs towards the end of the period. A cut-off low located over
southeast Texas will slowly drift eastward toward the region,
eventually bringing with it a stratus deck based at 4-5k ft. This
deck may lower to MVFR cigs, near 3k ft by 10-15z tomorrow at
KMEM and KJBR. Southerly winds increase to 6-12 kts today,
becoming light this evening.