818 
fxus64 kmeg 212337 aab 
afdmeg 


Area forecast discussion...updated 
National Weather Service Memphis Tennessee 
537 PM CST Sat Nov 21 2009 


Update... 
updated for aviation. 


&& 


Previous discussion... /issued 324 PM CST Sat Nov 21 2009/ 


Discussion...surface analysis this afternoon places an area of 
low pressure off the Louisiana coast while aloft an upper level 
low was located over East Texas. Skies have been mostly sunny with 
a gradual increase in clouds across north Mississippi this 
afternoon. Temperatures as of 3 PM CST are in the lower to middle 
60s across many locations. Rain chances tonight through Tuesday 
are the main challenges in this afternoon/S forecast package. 


Short term...(tonight through tuesday)...WRF/GFS short term 
models indicate weak surface/upper level low will continue to move 
east/northeast over the next 24 hours across Mississippi and 
Alabama. For the past few hours regional WSR-88D radar trends have 
shown an increase in returns over central/south Mississippi as 
isentropic ascent increases across the area. Metar observations have 
shown hourly rainfall amounts averaging around a hundredth at best 
thus far and agrees well thus far with light amounts advertised by short 
term model soundings. Rain chances will be limited to areas south 
of I-40 tonight and Sunday where best isentropic ascent /lift/ 
will be located. Any lingering rain Sunday will depart the middle 
south by late afternoon/early evening. 


Another cold front is expected to move through the lower 
Mississippi Valley Monday night into Tuesday morning. Raised probability of precipitation 
up to chance during this time frame...but expect overall rain 
amounts to be light. 


Long term...(tuesday night through saturday)...12z GFS/European model (ecmwf) in 
decent agreement with another upper level trough settling into the 
eastern United States by Thanksgiving into Friday. Rain free 
weather is expected during this period with near normal 
temperatures for November dropping to below normal values for 
late next week. 


Cjc 


&& 


Aviation... 
00z tafs 


Deep surface low pressure was located just off the la shore. MVFR 
ceilings were noted near the coast...while scattered middle and broken 
high clouds prevailed across the midsouth. 


Kgwx radar showed a band of light to moderate rain over central 
MS...headed north. This activity should arrive in the ktup area 
around 03z. 


As the surface low tracks northeast on Sunday... kmem/kmkl should 
be along the western periphery of rain...with occasional MVFR 
ceilings during the afternoon. Both GFS and NAM derived guidance 
brings ktup ceilings down to IFR conditions by late morning. Have 
generally followed the consensus...as ceilings could easily go IFR 
between bands of moderate rain. 


Pwb 


&& 


Preliminary point temps/pops... 
mem 48 62 46 62 / 20 10 10 10 
mkl 44 60 45 60 / 10 30 20 10 
jbr 44 61 44 62 / 10 10 10 10 
tup 46 56 46 63 / 70 40 20 10 


&& 


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


$$