Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Memphis Tennessee
1144 am CST Thursday Jan 29 2015
Updated to include 18z taf discussion.
Previous discussion... /issued 1008 am CST Thursday Jan 29 2015/
Skies are mostly sunny across the forecast area this morning with
temperatures ranging from the middle 50s to lower 60s. The cold front
has started to move into the forecast area from the northwest but
clouds are lagging behind the front at this time so it will take a
few hours before we see less sun. Made some minor changes to
clouds and temperatures for this afternoon.
Previous discussion... /issued 509 am CST Thursday Jan 29 2015/
Much milder night across the midsouth with mostly cloudy skies and
breezy south winds. Temperatures were in the middle 40s to upper 50s.
Warm air advection was taking place over the area producing a broken line of
showers just east of the Mississippi River. The best chance for
anything measurable will be across west Tennessee before sunrise.
For today...tonight and Friday...milder weather will be able to
sustain itself for one more day before a cold front seen in
Missouri passes through. Skies will generally be partly sunny as
gusty southwest winds...flirting close to advisory criteria this
morning diminish and veer northwest behind the boundary. Lighter
winds and variable cloudiness are expected tonight with much
cooler lows in the 20s and 30s. High pressure across the Midwest
will keep the region cool and dry tomorrow.
Saturday through Monday...models trending a bit further south with
the push of Arctic air this weekend. A deeper upper trough will
drop out of the Canadian prairie provinces...while the upper low
west of the Baja California moves east into Mexico. The upper flow over our
area will back from northwest to westerly allowing deeper moisture
to surge north out of Texas...and then a right turn east. Thus
clouds will quickly move into the region early Saturday...and with
winds remaining more easterly have trended cooler than forecast
guidance. Models show eastern extent of rain crossing Missouri
Saturday afternoon. This activity may clip portions of northeast
Arkansas and the bootheel region otherwise rain will likely move
into the midsouth Saturday night.
As the approaching wave moves closer on Sunday a surface low will
eject out of Texas and into the southeast states...while a 1040mb
surface high drops into the Dakotas. Both the European model (ecmwf) and GFS have
this solution with the leading edge of the Arctic air reaching the
northwest midsouth counties by afternoon...so have introduced a
rain/snow mix a bit earlier than previously thought. Believe
better chances for any minor snow accumulations will occur in the
evening hours. BUFKIT soundings indicate subfreezing 925mb
temperatures making their way down into north Mississippi before
precipitation shuts off...so with this...plan on wording a snow
threat in the morning severe weather potential statement. Late Sunday night the brunt of the
Arctic air will encompass the region...and with gusty north
winds...wind chills will drop into the teens. Clouds will linger
Monday with a few snow flurries possible. It will be cold as highs
for several midsoutherners will only climb into the low 30s.
Tuesday and Wednesday...southerly winds will push highs back into
the 40s and low 50s. Clouds will increase Tuesday night as models
depict the aforementioned upper low reaching the western Gulf. Any
precipitation for now appears to stay just to our south.
18z taf cycle
VFR conditions to begin the period as a front moves through the
region this afternoon. Winds will transition from the SW to the north
throughout the afternoon as frontal passage occurs. Gusts should
ease up this afternoon...but winds will remain near 10 kts from a
northerly direction throughout the evening. Included MVFR ceilings
for kmem...kjbr...and kmkl later this afternoon through tonight
as a low deck moves in from the northwest behind the front. Ceilings
should rise back to VFR after midnight with skies clearing late in
the period with winds again near 10 kts.