Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Memphis Tennessee
1048 am CST sun Jan 25 2015
Discussion...water vapor satellite/WSR-88D VAD wind profiles
place a closed upper level low over Missouri. This is producing
rain showers over the middle south...especially along and north of
I-40. Overall forecast is in good shape and only changes were to
adjust probability of precipitation and temperatures to account for short term trends.
Previous discussion... /issued 521 am CST sun Jan 25 2015/
updated for 12z aviation discussion.
Previous discussion... /issued 402 am CST sun Jan 25 2015/
Currently...a 1001 mb low pressure system is moving across
southern Iowa while a potent upper level trough pushes into the
middle Mississippi Valley. Middle and high clouds are increasing
north of I-40. Winds are southerly...5-10 miles per hour east of the MS
river and southwesterly 10-15 miles per hour west of the MS river.
Today...the potent upper trough will close off as it moves into the
western Ohio Valley. This system has acquired quite a bit of
moisture and the associated very cold air aloft will create steep
middle level lapse rates. Lifted index values actually fall to near
zero across much of the area from 18z-00z. A band of showers...now
developing across northwest Arkansas along and ahead of a developing
cold front...will move across areas north of I-40 this morning.
Winds will gradually veer from the southwest this morning to the
northwest this afternoon and become gusty. This afternoon expect
showers to re-develop as the upper low moves just north of the
area. Best chances for will be across northern and eastern
sections where probability of precipitation have been increased to likely. Will also
mention a slight chance of thunder due to the instability aloft.
Tonight...the upper low will quickly move east of the area though
scattered showers will linger into the evening over much of the
area...especially east of the MS river. Northwest winds will actually
strengthen during the evening with gusts to 30 miles per hour. Low clouds
will invade the entire midsouth overnight so expect temperatures to drop
only into the middle and upper 30s.
Monday...beginning to think low clouds will linger for a
while...especially across the east. Strong northwest flow aloft...weak
surface high pressure and lingering clouds will lead to a cool day
with highs from the low 40s near Paris to around 50 in Clarksdale.
Monday night through Wednesday...a pleasant period transitioning
from northwest flow aloft to broad upper ridging across the region by
Wednesday. Weak high pressure will prevail at the surface. High
temperatures will be a little above average with readings in the 50s.
Lows generally in the 30s except from some 20s along the Tennessee River
Wednesday night into Thursday...a moisture starved cold front will
push through with only slight chance for rain across mainly
eastern sections. Temperatures will still be mild with highs in the 50s
Friday and Saturday...cool high pressure will settle over the
region with highs back in the 40s. Precipitation looks to remain
mostly to the south and west.
VFR weather to start. But as a disturbance pushes through
conditions will start to flirt between VFR and MVFR...before
settling to MVFR late. Scattered rain showers will also develop
along a cold front...and their is an afternoon threat for a stray
thunderstorm. Gusty winds will also be a concern...starting off
southwest...and veering west and northwest behind the front.
Winds will subside some near the tail end of the period.