MESOSCALE PRECIPITATION DISCUSSION 0208
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
612 AM EDT FRI AUG 09 2013
 
AREAS AFFECTED...SOUTHERN KS...SOUTHWEST MO...NORTHEAST
OK...NORTHWEST AR 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 090954Z - 091454Z
 
SUMMARY...SUSTAINED LIFT IN A MOIST AND WEAKLY UNSTABLE
ENVIRONMENT MAY YIELD ENOUGH RAINFALL TO CAUSE FLASH FLOODING IN
THE MOST SUSCEPTIBLE AREAS.

DISCUSSION...THE THURSDAY EVENING CONVECTIVE EVENT HAD MOWED
THROUGH MOST OF THE NEAR-SFC BASED INSTABILITY OVER THIS
REGION...BUT AT 0930Z RADAR STILL SHOWED POCKETS OF HEAVY RAIN
FROM BOTH SHALLOW UPDRAFTS IN KS AND DEEPER UPDRAFTS IN OK. OUR
CONCERN FOR HEAVY RAIN FOCUSES MAINLY IN TWO AREAS. FIRST THE WEST
TO EAST ORIENTED 700 MB TROUGH AXIS IN SOUTHERN KS AND MO.
CONVERGENCE OF 850 MB WINDS ALSO FOCUSES ALONG THIS AXIS...AND THE
RAP FORECASTS CONTINUED LIFT HERE THROUGH 15Z AND BEYOND. RAINFALL
HAD BEEN LOCALLY EFFICIENT IN NORTHERN OK EARLIER...WHERE 1-1.5
INCHES IN AN HOUR HAD BEEN NOTED PER THE OK MESONET. COVERAGE OF
INTENSE ECHOES HAD DECREASED BUT HEAVY RAIN COULD STILL BE FOUND
BASED ON DUAL POL DATA IN SOUTHERN KS. THE 00Z WRF ARW AND NSSL
WRF HAD HANDLED THE 06-09Z TIME FRAME RATHER WELL...AND BOTH
SUGGEST NARROW WEST-EAST BANDS OF MODERATE RAINFALL ACROSS KS/MO.
WITH AN EFFICIENT WARM RAIN PROCESS LIKELY TO EXIST IN THE SHALLOW
CONVECTION HERE...1-2 INCHES OF RAIN ARE POSSIBLE LOCALLY...WHICH
MAY JUST EXCEED THE LOW FLASH FLOOD GUIDANCE VALUES OVER 1 TO 3
HOURS.

MEANWHILE...DEEPER UPDRAFTS REMAIN POSSIBLE OVER CENTRAL/EASTERN
OK...EVENTUALLY WORKING INTO NORTHWEST AR...AS SOUTH TO
SOUTHWESTERLY LOW LEVEL FLOW PRODUCES UPGLIDE NORTH OF THE
RECENTLY REINFORCED FRONTAL ZONE. MODELS SHOW GRADUAL 700 MB
DRYING WORKING IN FROM THE WEST TO YIELD AN EASTWARD MOVEMENT TO
THE ACTIVITY...BUT WITH THE POTENTIAL FOR A FEW ROUNDS OF HEAVY
DOWNPOURS BEFORE ENDING AT A GIVEN LOCATION. HERE NEW RAINFALL
TOTALS COULD EXCEED 2 INCHES LOCALLY GIVEN THE DEEPER CORES AND
HIGHER RAIN RATES. 

BURKE

ATTN...WFO...PAH...LZK...SGF...EAX...TSA...TOP...ICT...OUN...
DDC...

ATTN...RFC...ABRFC...LMRFC...MBRFC...NCRFC...

LAT...LON   38159231 37609136 37119119 36149162 35069370 34459582
            34459712 35029748 36259727 36799773 36959893 38069888
            38439458 38159231