Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Memphis Tennessee
531 am CST Wednesday Nov 25 2015
Updated for 12z aviation discussion
Previous discussion... /issued 323 am CST Wednesday Nov 25 2015/
.Heavy rain possible over parts of the midsouth this Holiday
Currently...surface high pressure is situated over the southeast
U.S. With just a few high clouds moving through the region at this time.
Temperatures are seasonably cool with readings in the 30s and lower 40s.
Today through Thanksgiving...as an upper low digs into the
southwest U.S an upper ridge will build across the middle south.
Expect dry and mild conditions with highs climbing well into the
60s by Thanksgiving. Overnight lows will continue to moderate each
night as well.
Thanksgiving night through Sunday night...a slow moving cold
front will being to push into the region on Friday and stall
across the northern part of the midsouth through much of the
Holiday weekend. A very moist airmass will overrun this frontal
boundary. Very strong 850 mb moisture transport is expected into
the region with precipitable waters greater than 1.5 inches. Latest 00z
GFS/European model (ecmwf) runs are in good agreement placing the heaviest rain
along and north of Interstate 40 where 3 to 5 inches is a good
bet. Northeast Arkansas and the Missouri bootheel should see the
heaviest rainfall in our area with some places receiving more than
5 inches by 12z Monday. The ground is still fairly wet from heavy
rain last week so flooding will be a concern. Will continue to
highlight this in the severe weather potential statement. Since the front will be stalled well to
the northwest for much of the weekend areas to the southeast
should see less rain and should salvage a fairly nice Holiday
weekend...at least through Saturday. Eventually a middle level
shortwave pushing through the lower Mississippi Valley will cause
a surface low to develop and track along the cold front on Sunday.
This will help push the front southeast and spread rain into
southeastern parts of the forecast area. Rain should taper
off...at least temporarily Sunday night.
Temperatures will start off mild Friday and gradually cool down
through the weekend as the front and rain spread southeast
Monday and Tuesday...model discrepancies show up early next week.
Both models have a closed upper low over the northern U.S. On
Monday but the European model (ecmwf) has a potent piece of energy rotating around
this upper low. This results in cyclogenesis over the middle
Mississippi Valley. This system could bring rain back into the
area as soon as Monday...continuing into Tuesday. The GFS has a
much weaker and drier solution for the same time period. Until
things clear up will carry chance probability of precipitation Monday-Tuesday for now and
12z taf cycle
VFR conditions will persist for the entire forecast period. Winds
will be mainly from the south at around 5 knots this and then
increasing to 10 to 15 knots this evening.