Scientific Forecaster Discussion

NWS Discussion
			
				

Area forecast discussion 
National Weather Service Norman OK 
637 PM CDT Tuesday may 21 2013 


Aviation...00z taf issuance... 
VFR conditions will prevail through the evening and overnight. 
Skies will continue to clear from west to east across western and 
central OK this evening as the upper level low continues to shift 
eastward this evening. Some scattered to broken middle level clouds will 
likely linger across northwestern OK through Wednesday morning 
before dry south/southwest flow takes hold through noon Wednesday. 
Light and variable winds through the morning hours will result in 
possible MVFR to IFR fog at aerodromes across central and southern 
Oklahoma. Increasing west/southwest winds Wednesday morning from 
southwest OK/western North. Texas into central OK will allow any widespread 
fog to lift quickly through sunrise. 


Jtk 


&& 


Previous discussion... /issued 212 PM CDT Tuesday may 21 2013/ 


Discussion... 
the main forecast challenges for this package will be ongoing 
convection across Oklahoma and North Texas...and forecasting 
shower/storm chances over the coming week...which may hamper 
search and Rescue efforts in central Oklahoma. 


A strong upper level wave of low pressure is moving across the 
Southern Plains. Recent WV imagery shows a well pronounced dry 
slot developing west of an eastward moving line of strong to 
severe storms extending from just east of Holdenville...southward 
to near Tishomingo and Lake Texoma. At times...strong to severe 
wind gusts have occurred with this complex...and storms are likely 
to remain strong to severe. The threat for severe weather is 
expected to continue into the evening. In addition to the severe 
threat...persistent heavy rainfall has led to occurrences of 
flash flooding and possibly river flooding over parts of south 
central and southeast Oklahoma. Do not drive through flood waters 
if you come across them on the roadway! 


Further north...with cooler and drier air filtering into the 
region...and with expansive cloud shield and increasing 
stability...expect mainly light to moderate rain over most of 
northern and central Oklahoma...with occasional thunder. 


By tonight...most activity will have exited the region...with 
clouds hanging around southeast Oklahoma. With residual moisture 
in place...and surface high pressure moving in behind as passing 
front...patchy to widespread fog may develop...especially from 
central Oklahoma southeastward. Patchy dense fog may even develop 
near sunrise...as winds go calm...causing hazardous driving 
conditions. 


For the rest of this week...flat middle level ridging will build 
into Oklahoma and North Texas. With several small scale impulses 
moving along the northern periphery of the ridge...at least 
isolated shower and thunderstorm activity will be possible each 
day over the coming week. This will mainly be driven by diurnal 
heating. Rain chances will increase from this weekend into early 
next week...as a large upper storm system emerges into the 
Southern Plains. For now...will keep chance probability of precipitation or less through 
the entirety of the forecast period. 


Regarding search and Rescue operations in the south Oklahoma City 
metropolitan area...expect main impacts in the short term to be light 
shower activity...which will diminish by this evening. Any fog 
development that occurs tonight into tomorrow morning will make 
Rescue operations difficult. Cool morning temperatures and patchy 
fog will yield to mild temperatures and mostly clear to partly 
cloudy skies by early afternoon tomorrow. Again...at least a 
slight chance of storms will linger into the weekend...so 
personnel involved in cleanup and Rescue activities will need to 
monitor the weather situation closely over the coming days. 


&& 


Preliminary point temps/pops... 
Oklahoma City OK 73 56 80 60 / 90 10 0 20 
Hobart OK 75 53 87 60 / 40 0 10 10 
Wichita Falls Texas 76 58 89 63 / 90 10 0 10 
gage OK 78 48 85 56 / 10 0 10 20 
Ponca City OK 75 51 80 57 / 30 10 0 30 
Durant OK 77 59 85 64 / 100 30 0 10 


&& 


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


$$ 


03/04/04