Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Memphis Tennessee
1222 PM CDT Friday Jul 3 2015
updated for 18z aviation discussion.
Previous discussion... /issued 951 am CDT Friday Jul 3 2015/
updated to lower high temperatures and increase afternoon probability of precipitation.
Significant rainfall and cloud cover throughout the day will keep
high temperatures in the upper 70s...to maybe the low 80s today.
So lowered forecast highs accordingly. Second complex of storms
now moving into the southwestern Delta counties and extends west
of Little Rock. This area of rain will slide east over already
well saturated ground in north Mississippi producing an
additional rainfall of up to 5 inches. As a result have increased
afternoon probability of precipitation in the flash Flood Advisory...and lowered them slightly across the
far north where activity will be more scattered.
Previous discussion... /issued 404 am CDT Friday Jul 3 2015/
the recent wet pattern will continue today...courtesy of an
unseasonal upper level longwave trough over the MS River Valley.
Early morning GOES water vapor imagery showed a shortwave trough
centered over Iowa. This feature will deamplify and lift east to
the southern Great Lakes today...while a positively tilted middle level
trough axis drops through the lower and middle MS river valleys.
This midlevel trough axis will aid in airmass destabilization over
the midsouth today...ahead of an approaching surface cold front.
By late this evening... the cold front will likely extend along
the i40 corridor...with greatest rain chances occuring along and
south of the front.
Saturday will mark the beginning of weakening flow aloft...as the
southern extension of the positively tilted trough is separated
from its northern branch component. Daytime convective inhibition
will remain weak...especially over north MS...in in the vicinity
of the upper trough axis.
Upper level heights will gradually build during the early part of
next week...but still remain below climatological norms. GFS forecasts
precipitable water values near 2 inches...with weak daytime
convective inhibition. Daytime temperatures will likely warm to a few
degrees shy of normal by midweek...but will be locally affected
by scattered afternoon thunderstorms.
18z taf cycle
Very active taf period with multiple rounds of showers and
T-storms. Heaviest activity will produce temporary IFR
conditions...and possibly brief LIFR visibility. Later tonight outside
of storms stratus is expected to form with borderline LIFR/IFR
ceilings. Not anticipating much improvement with conditions before
04/18z. Winds will be south to southwest at 5 to 10 kts...with
potential gusts up to 20 kts in T-storms. Winds will begin to
swing north to northeast at jbr late.
Arkansas...Flash Flood Watch through Saturday evening for Crittenden-cross-
Lee AR-Phillips-St. Francis.
MS...Flash Flood Watch through Saturday evening for Alcorn-Benton MS-
Tennessee...Flash Flood Watch through Saturday evening for Fayette-Hardeman-