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fxus64 klzk 231147 
afdlzk 


Area forecast discussion 
National Weather Service Little Rock Arkansas 
547 am CST Monday Nov 23 2009 


Aviation... 
high pressure continues over the area with low pressure developing 
in The Rockies. This low will move into the plains by tonight and 
bring a cold front with it. The low will remain north of Arkansas 
but the front will enter the state late tonight. Southerly winds 
will continue to bring moisture into the state today and tonight. 
Patchy fog will lift by middle morning but the clouds will remain 
over the area this afternoon and tonight. LIFR and IFR conditions 
are expected this morning before becoming MVFR. Patchy fog will 
develop again tonight central and south. 


&& 


Previous discussion... /issued 251 am CST Monday Nov 23 2009/ 


Discussion... 
main concerns this forecast cycle are chances of rain with system 
on Tuesday...then temperature forecast with cold air Wednesday and 
Thursday. 


At the surface...weak high pressure over the area with a return 
south wind flow bringing back moisture to the area. 00z klzk 
sounding had a precipitation water value of 0.71 inches...while surface 
dew points have increased to the lower 50s over southern and 
central Arkansas. Stratus was forming across much of Arkansas with ceilings 
mainly 800 feet to around 3k feet. Patchy fog was also seen forming 
in spots. Aloft...shortwave seen moving across the upper plains 
and will push to the Great Lakes...while second system over the 
northern rockies and is expected to deepen and move more 
southeast. 


Short term...today through Thursday night 
patchy morning fog will start the forecast with mostly cloudy 
skies. Expect clouds to dissipate and thin today bringing partly 
sunny conditions. Mild temperatures will hold today helped by the south 
flow. Then tonight...increasing clouds ahead of the cold front and 
upper system as it moves east. With a weak 850mb jet...precipitation 
water values reach around one inch along the cold front as it 
moves through Arkansas on Tuesday. Chance Cat is in forecast...but 
return is limited...as well as instability...and overall rain 
amounts expected to be less than a quarter of an inch. Most areas 
will see a tenth of two or less. Still not impressed with 
instability and would only expected a few elevated showers than 
might have the potential for lightning...so will continue to keep 
thunder out of forecast. Some differences in model timing of the 
cold front do exist...with GFS still a bit faster than NAM and 
European model (ecmwf)...but differences are becoming less with each run. Forecast 
does taper rain chances off Tuesday evening...clearing things late 
evening. The surface low lifts across MO to the Ohio Valley... 
while the cold front is out of Arkansas by 00z Wednesday. Cooler temperatures 
Tuesday night and Wednesday. Then the secondary cold surge will 
bring much cooler air on Wednesday night and Thanksgiving day. 
Used close to mav temperatures today and tonight...but went a bit cooler 
Wednesday through Thursday. 


Long term...Friday through Sunday 
low pressure aloft will be over the eastern Great Lakes and the 
West Coast with a well amplified ridge over The Rockies to begin 
the period. The ridge will move east into Arkansas Saturday. 
Models are in agreement the western trough will dig into the 
central part of the country Sunday but the GFS is a bit slower. 


Surface high pressure and subsidence will be over the area Friday 
and Saturday. The high will move east of the area Saturday night and 
to the East Coast Sunday. Return flow will bring moisture back into 
the area ahead of a cold front moving through the plains. Will bring 
in showers Sunday with increasing chances through the day as 
moisture becomes more abundant and the front approaches. Near normal 
temperatures are expected through the period with lows in the 30s 
and 40s and highs in the 50s mainly. 


&& 


Preliminary point temps/pops... 
Batesville Arkansas 62 48 60 37 / 0 20 50 30 
Camden Arkansas 69 49 64 39 / 0 20 50 30 
Harrison Arkansas 61 46 56 35 / 0 30 40 20 
Hot Springs Arkansas 66 48 62 37 / 0 20 50 20 
Little Rock Arkansas 65 48 62 38 / 0 20 50 30 
Monticello Arkansas 68 48 65 40 / 0 10 40 30 
Mount Ida Arkansas 66 47 61 37 / 0 30 40 20 
Mountain Home Arkansas 60 47 58 36 / 0 20 50 20 
Newport Arkansas 62 47 61 39 / 0 10 40 30 
Pine Bluff Arkansas 66 48 64 39 / 0 10 40 30 
Russellville Arkansas 64 47 59 36 / 0 30 50 20 
Searcy Arkansas 63 48 61 39 / 0 10 40 30 
Stuttgart Arkansas 65 48 62 40 / 0 10 40 30 
&& 


Lzk watches/warnings/advisories...none. 
&& 


$$ 




Aviation...51