408 
fxus64 kmeg 231140 
afdmeg 


Area forecast discussion 
National Weather Service Memphis Tennessee 
540 am CST Monday Nov 23 2009 


Update... 


Updated for 12z taf discussion. 


&& 


Previous discussion... /issued 447 am CST Monday Nov 23 2009/ 


Discussion... 
skies will remain mainly overcast across the midsouth through the 
day as low level moisture remains trapped under a strong 850 mb 
inversion. This combined with light southerly surface flow will 
keep temperatures about the same as yesterday. The region should 
remain dry through the day. Some patchy fog is possible mainly 
along the Tennessee River valley later this evening and through 
the overnight hours. 


Strong 500 mb trough will make its push toward the Ohio Valley on 
Tuesday. The associated surface low will push toward the Great 
Lakes and swing a cold front though the area Tuesday afternoon. 
The front will occlude in the vicinity of the midsouth and with 
the lack of decent forcing...believe the area will experience only 
a few light rain showers Tuesday evening. 


Skies will slowly begin to clear Wednesday into Thursday. A much 
stronger 500 mb shortwave will follow the first and bring sharp height 
falls into the midsouth Thursday. Models depict 850 mb temperatures 
in the -4c to -6c range Friday morning which would translate to 
surface temperatures near the freezing mark. Dry high pressure 
from the Southern Plains will then build into the area keeping 
temperatures below normal through Saturday. 


Southerly surface flow will return Sunday as high pressure slides 
east of the area. Surface low pressure will then slide east across 
central Mississippi and Alabama bringing chances for showers back 
to the midsouth Monday into Tuesday. Models diverge at this point. 
The European model (ecmwf) builds another surface ridge into the area. The GFS on 
the other hand depicts a much stronger 500 mb trough digging deep into 
the Southern Plains and slowing the surface low and subsequent 
ridge development. 


Ccd 


&& 


Aviation... 


12z taf cycle 


Low ceilings and visbys persist at most taf sites this morning with 
IFR down to vlifr conditions occurring. Expect ceilings and visbys to 
slowly improve by middle to late morning but still expecting MVFR 
conditions to persist through the day with a persistent overcast 
as low level inversion remains strong trapping low level moisture. 
Winds should remain light southeasterly today as well. 


Skies may temporarily become broken for a period later this 
evening...especially at mem and jbr...but should quickly fill in 
and deteriorate later tonight with IFR or lower ceilings and visbys 
redeveloping and persisting through the early morning hours of 
Tuesday at all taf sites. 


Jlh 


&& 


Preliminary point temps/pops... 
mem 62 49 63 45 / 0 10 50 20 
mkl 57 46 61 41 / 10 10 40 20 
jbr 62 46 61 40 / 10 10 50 10 
tup 58 46 64 44 / 0 10 20 20 


&& 


Meg watches/warnings/advisories... 
Arkansas...none. 
MO...none. 
MS...none. 
Tennessee...none. 
&& 


$$