Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Memphis Tennessee
432 am CDT Sat Apr 25 2015
early morning GOES water vapor imagery showed a closed upper low
centered over northeast Kansas. Ahead of the upper low...a large
plume of middle and upper level subtropical moisture extended from
central Mexico... across Texas...into the Ohio Valley. At the
surface... 09z surface map showed a surface low over northeast
Kansas...with a warm front extending southeast to near St Louis...
southeast toward the Ohio River. Further south... a marine warm
front was located along the i20 corridor of MS. The midsouth was
free of rain as of 0915z / 415 am CDT.
As the morning progresses... expect the upper low to lift east
into the middle MS River Valley...with storms developing east of the
low along the northern warm front. Further south... model solutions
vary with respect to rain chances in the dry slot over the midsouth.
Surface winds should veer to the southwest during the middle to late
morning. Even with the arrival of higher surface dewpoints...
expect insufficient forcing to overcome a rather Stout cap at
900mb. This cap will be weaker further north toward the Kentucky border.
Will maintain chance probability of precipitation and slight risk severe over portions of
northwest Tennessee through midday...but confidence is limited given
weaker capping and better positioned warm front in the Ohio
Valley. Otherwise... dry... breezy and mild over the midsouth
today. Will need to monitor winds for possible advisory.
Dry conditions should prevail until a southern branch cutoff upper
low passes through Tuesday and Wednesday. 00z GFS and European model (ecmwf) were
in fair agreement...with best rain chances south of i40.
The latter portion of next week appears dry...with weak northwest
upper level flow transitioning to upper level ridging and
slightly below normal temperatures moderating to near normal
values by next weekend.
06z taf cycle
Ceilings frequently IFR overnight with widespread showers and
scattered thunderstorms. Southeast winds continuing to turn more southerly
and increase in speed as a warm front lifts north through the region
Following the passage of the warm front...scattered showers and
thunderstorms can be expected late tonight into the morning hours
of Saturday. Skies will eventually scatter out with VFR ceilings
and a reduction in storm chances from west to east later Saturday
morning as a middle level dry slot surges into the region. Winds will
continue to veer southwesterly and westerly and increase in speeds
Saturday morning. Southwest to west winds becoming strong and
Winds diminishing Saturday evening with VFR conditions.