Forecast Discussion

FXUS64 KMEG 190540

Area Forecast Discussion
National Weather Service Memphis TN
1140 PM CST Mon Nov 18 2019

Updated to include 06Z Aviation Discussion.


.PREV DISCUSSION... /issued 657 PM CST Mon Nov 18 2019/

A broad trough sits over the eastern CONUS this evening with
northwesterly flow aloft over the Plains providing an active storm
track across the Mid-South. A shortwave trough is moving across
the region this evening and will provide large scale ascent
through the overnight hours. This lift will be enhanced by the
indirect thermal circulation associated with the left exit region
of an approaching 120 kt jet streak on the backside of the
trough. An abundance of mid-level cloud cover is already in place
across the CWA, but the sub-cloud layer remains relatively dry
with surface dewpoints in the mid 30s to near 40F. We anticipate
a few showers tonight, but it may still take a few hours to
adequately saturate the air mass. Coverage will remain limited and
QPF light, so no change was made in to the first period, slight
chance PoPs. Other changes were minor but included increasing wind
speeds slightly on Tuesday and cloud cover tonight. Any showers
that develop tonight are expected to move east of the CWA before


PREV DISCUSSION... /issued 331 PM CST Mon Nov 18 2019/


Currently...The next upper level disturbance is sliding toward
the area in the NW flow aloft. Mid and high clouds are on the
advance across the region. Temps are in the mid 50s across the
Mid-South this afternoon or about 5 degrees below normal. Winds
are light NW east of the MS River and gradually backing toward the
SW as the next upper disturbance approaches.

Tonight through Wednesday...Upper level disturbance will slide
through the area overnight. SREF ensemble members are spitting out
some light showers as the disturbance moves through. Some places
may pick up a hundredth of an inch...most will not. Clouds will
help keep temps a little warmer with lows in the lower 40s.
Tuesday and Wednesday will be really nice days with plenty of sun
and warmer temps with highs in the 60s.

Wednesday night through Saturday...A wet period is in store for
the Mid-South. A cold front will push toward the area by
Thursday then stall over northern sections Thursday night into
early Friday before pushing through the region Friday night as an
upper low over the SW US ejects eastward. Right now it looks like
1.5 to 2 inches of rainfall is possible with this event. Severe
weather potential is very low. Some thunder is possible late
Thursday night into Friday as some elevated instability moves over
the area. There is some discrepancy on how quickly this system
exits the region. 12z runs are a little faster and as a result
Saturday...and perhaps even Friday evening...are looking drier so
have lowered pops some from the previous forecast. Cooler air
will push in for the weekend with highs in the 50s.

Sunday and Monday...Dry and cool with highs in the 50s.



/06Z TAFs/

VFR conditions expected to prevail through the period. SW winds
overnight will veer NW with passage of a shortwave trough. LLWS
remains a possibility at MEM over the next couple of hours with W
winds around 2000 ft up to 35 kts. NW winds between 8-11 kts will
become light/calm by Tuesday evening.