Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Memphis Tennessee
1140 PM CDT Sat Mar 15 2014
updated for 06z aviation.
Previous discussion... /issued 911 PM CDT Sat Mar 15 2014/
As of 9pm...a wide swath of rain located over most of
Arkansas...Mississippi...and Louisiana is beginning to move into
the southwestern half of our forecast area. Latest GOES-r water
vapor imagery shows a robust upper level low pressure system
churning over northern Texas right now. A few instances of large hail
have been reported...but mostly heavy rain has been associated with
this storm system thus far.
This system and an associated surface low are expected to track
eastward this evening...bringing periods of heavy rain as well as
some rumbles of thunder to the middle-south overnight. No storms are
expected to reach severe thresholds. Temperatures will cool into
the 50s overnight as rain overspreads the region. The rain is
expected to continue through at least tomorrow evening.
Trimmed back probability of precipitation a bit before 03z to reflect current
radar trends. All other forecast parameters look good.
New zones and grids will be available shortly.
Previous discussion... /issued 641 PM CDT Sat Mar 15 2014/
updated for 00z aviation discussion.
Previous discussion... /issued 340 PM CDT Sat Mar 15 2014/
Discussion...20z surface analysis places a developing surface low
over the Texas/Oklahoma Panhandle. Latest surface observations
indicate weak southerly flow occurring across the middle south this
afternoon with temperatures as of 3 PM CDT in the middle to upper
60s at most locations. Precipitation chances tonight through
Sunday night...including a potential for wintry precipitation
Sunday night...and Wind Advisory potential mainly Sunday afternoon
are the predominant forecast concerns in this afternoon/S forecast
Short term...(tonight through Sunday night)...short term models remain
in decent agreement as a surface low currently located over the
Texas/Oklahoma Panhandle deepens slightly as it moves into the
lower Mississippi Valley by Sunday morning and over north
Mississippi by Sunday afternoon. Rain showers over the lower
Mississippi Valley has been limited at best thus far with most
areas remaining dry throughout the day. Latest water vapor
satellite/WSR-88D VAD wind profiles indicate better moisture and
lift will arrive tonight as lift and moisture increase in advance
of an upper level trough located over West Texas and eastern New
Mexico. This will result in showers across the middle south tonight
with perhaps an elevated thunderstorm or two possible. As the low
moves across north Mississippi tomorrow afternoon...north winds
will increase on the back side of the low...especially along and
west of the Mississippi River. Short term models indicate
conditions could become favorable for some wake low type winds in
this area mainly from Sunday afternoon towards early Sunday
evening as the pressure rises quickly. Will let evening/midnight
shifts assess Wind Advisory potential and coverage once the 00z
model run has arrived. Nonetheless...will mention a potential for
a Wind Advisory in the hazardous weather outlook.
Models still indicate a potential for some precipitation in the
deformation zone on the back side of the low Sunday night. As
temperatures fall towards or slightly below freezing Sunday night
across areas mainly north of I-40...there remains a potential for
some of the rain to change over to a sleet/snow mixture. At this
time it appears that precipitation will be light and confidence on
headlines/impacts on the low end in this forecast.
Regardless...evening/midnight shifts will continue to monitor
winter weather potential in tonight/S 00z model data and assess
whether a winter headlines may be warranted across a portion of
the middle south Sunday night.
Long term...(monday through saturday)...12z GFS/European model (ecmwf) long term
models indicate high pressure will return across the middle south
Monday and persist across the middle south through Tuesday. Long term
models indicate a weak front will move across the region Tuesday
night into Wednesday. However...moisture is anticipated to be too
limited to support precipitation and have left this period dry for
now. Beyond Wednesday...another cold front will move across the
region Friday night into Saturday and will handle with slight
chance probability of precipitation until models come into better agreement.
Rain shield was moving into the midsouth at 0430z...ahead of an
upper level low south of okc. Few changes anticipated for the 06z
tafs. Ts potential will likely arrive after 09z...with the approach
of the upper low.