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fxus64 koun 221118 
afdoun 


Area forecast discussion 
National Weather Service Norman OK 
618 am CDT Monday Mar 22 2010 


Aviation... 
VFR with only a modest increase in cirrus. Winds coming around to 
S on back side of surface ridge. Air aloft will remain exceptionally 
dry - relative humidity below 15 percent - at least up to 500mb through the forecast 
period. 


&& 


Previous discussion... /issued 351 am CDT Monday Mar 22 2010/ 


Discussion... 
most of the snow cover melted off Sunday and the rest of it should 
go today courtesy of the late-March sun... setting up a quick 
return of Spring today through Tuesday beneath ridging aloft. The 
only inhibiting factor might be the front that sags into northwest OK on 
Tuesday... but the main cooling is likely to hold off until Tuesday 
night and Wednesday as the front moves farther into southeast OK and ncentral 
Texas. Light rain... mainly Post frontal... may start spreading into 
northwest OK late Tuesday night before becoming more widespread Wednesday. 
Convection will become more likely near and just to the cool side 
of the surface front late Wednesday into Wednesday night in response to low-level 
warm advection and cooling aloft with the approaching upper trough. 
T-storms will be more likely over the southeast half of the County Warning Area. 
Boundary-layer relative humidity forecasts indicate widespread stratus developing S 
of the front across Texas Tuesday night and likely lingering over much of 
the area Wednesday. Result will be limited heating of the low levels... 
which along with only modest return of low-level moisture will 
lead to very limited instability. Thus mainly a stratiform event 
for most of the area. There are some model timing differences 
regarding how fast the upper system and the surface low will move out 
on Thursday... but all seem to agree that precipitation will have moved east of 
the area by Thursday evening. Canadian air will not make it this far SW 
before the system exits... so this one looks like all rain with 
only a low-end chance of a changeover late in far northwest OK. 


Another system moves through quickly toward next weekend. This one 
appears likely to set up more like a typical early-Spring 
dryline-type event for TX/OK... but like its predecessors will 
probably be fueled by modified Gulf air. As such it may suffer 
from limited Gulf moisture/instability. Nonetheless the GFS shows 
an axis of 1000-1500 j/kg SBCAPE by late Sat into west OK along the 
dryline... so we will need to keep an eye on it. 


&& 


Preliminary point temps/pops... 
Oklahoma City OK 63 39 70 49 / 0 0 0 10 
Hobart OK 63 37 69 45 / 0 0 0 10 
Wichita Falls Texas 68 42 78 51 / 0 0 0 10 
gage OK 69 36 67 41 / 0 0 0 20 
Ponca City OK 55 37 65 43 / 0 0 0 10 
Durant OK 61 39 73 50 / 0 0 0 10 


&& 


Oun watches/warnings/advisories... 
OK...none. 
Texas...none. 
&& 


$$ 


30/24/24