903  
AWUS01 KWNH 191903  
FFGMPD  
MOZ000-ARZ000-OKZ000-200100-  
 
MESOSCALE PRECIPITATION DISCUSSION 0962  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
302 PM EDT TUE AUG 19 2025  
 
AREAS AFFECTED...THE OZARKS  
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE  
 
VALID 191902Z - 200100Z  
 
SUMMARY...SHOWERS AND THUNDERSTORMS DEVELOPING AHEAD OF AN MCV  
WILL EXPAND IN COVERAGE THROUGH THE AFTN. RAINFALL RATES OF  
1-2"/HR ARE EXPECTED, WHICH COULD RESULT IN 2-3" OF RAINFALL WITH  
LOCALLY HIGHER AMOUNTS. FLASH FLOODING IS POSSIBLE.  
 
DISCUSSION...THE REGIONAL RADAR MOSAIC THIS AFTN DEPICTS RAPID  
EXPANSION OF INCREASING REFLECTIVITY ASSOCIATED WITH DEVELOPING  
CONVECTION FROM SOUTHEAST MISSOURI THROUGH FAR EASTERN OKLAHOMA.  
THESE THUNDERSTORMS ARE DEVELOPING IN RESPONSE TO ASCENT PRODUCED  
THROUGH WEAK UPPER LEVEL DIRECTIONAL DIVERGENCE ATOP SUBTLE HEIGHT  
FALLS AS A CONVECTIVELY ENHANCED SHORTWAVE AND REMNANT MCV TRACKS  
SOUTHWARD FROM MISSOURI. AN OUTFLOW BOUNDARY (OFB) AHEAD OF THIS  
MCV NOTED IN SATELLITE IMAGERY IS PRODUCING ADDITIONAL LIFT  
THROUGH CONVERGENCE, WHILE GENERAL N/NW FLOW IS PRODUCING MODEST  
UPSLOPE ASCENT INTO THE OZARKS AS WELL. THIS ASCENT IS ACTING UPON  
FAVORABLE THERMODYNAMICS CHARACTERIZED BY PWS MEASURED BY GPS OF  
1.7 TO 1.8 INCHES, AROUND THE 90TH PERCENTILE FOR THE DATE,  
COLLOCATED WITH MUCAPE AROUND 3000 J/KG SOUTH OF THE OFB.  
 
CELLS THAT HAVE DEVELOPED SO FAR HAVE BEEN GENERALLY SMALL WITH  
NARROW UPDRAFTS, WHICH WITHIN THE PULSE ENVIRONMENT (LIMITED BULK  
SHEAR) IS KEEPING RAINFALL INTENSITY TO AROUND 0.5-1"/HR WITH  
SHORT TEMPORAL LIFESPANS. HOWEVER, THE CAMS SUGGEST THAT  
THUNDERSTORMS WILL BECOME MORE WIDESPREAD AND INTENSE AS THE MCV  
AND OFB DROP SOUTHWARD INTO THE EVENING, AND AS COVERAGE  
INCREASES, STORM MERGERS AND COLLISIONS WILL LEAD TO REGENERATING  
CELLS WITH LONGER LIFETIMES. DURING THIS TIME, PWS ARE LIKELY TO  
INCREASE TO ABOVE 2", SUGGESTING THE THERMODYNAMIC ENVIRONMENT  
WILL BECOME EVEN MORE FAVORABLE AS THE FORCING INTENSIFIES, WITH  
THE RESULT BEING HREF NEIGHBORHOOD PROBABILITIES FOR 2"/HR RAIN  
RATES PEAKING ABOVE 30%. ALTHOUGH CELLS SHOULD STEADILY MOVE  
SOUTHWARD ON MEAN 0-6KM WINDS OF 5-10 KTS, PROPAGATION VECTORS MAY  
VEER SUFFICIENTLY TO ALLOW REDEVELOPMENT UPSTREAM SUGGESTING THAT  
IN ADDITION TO STORM MERGERS, SOME AREAS COULD RECEIVE REPEATING  
ROUNDS OF THUNDERSTORMS. WHERE THIS OCCURS, TOTAL RAINFALL OF  
2-3", WITH LOCALLY 3-4", IS POSSIBLE AS REFLECTED BY HREF  
EXCEEDANCE PROBABILITIES FOR 3"/6HRS OF 40%.  
 
SOILS ACROSS THIS AREA ARE GENERALLY DRY ACCORDING TO NASA SPORT  
DUE TO MINIMAL RECENT RAINFALL NOTED VIA AHPS. THIS HAS ALLOWED  
FFG TO REACH 3-4"/3HRS. WHILE THIS SHOULD LIMIT THE MAGNITUDE AND  
COVERAGE OF ANY FLASH FLOODING, ISOLATED IMPACTS ARE POSSIBLE  
WHERE ANY REPEATING CELLS CAN OCCUR, ESPECIALLY WITHIN URBAN AREAS  
OR ANY MORE SENSITIVE TERRAIN.  
 
WEISS  
   
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT  
 
ATTN...WFO...LSX...LZK...MEG...PAH...SGF...TSA...  
 
ATTN...RFC...KRF...MSR...ORN...TUA...NWC...  
 
LAT...LON 37639064 37638986 37418952 36988951 36248997  
35739069 35389151 35249225 35029322 34849408  
34769465 34749508 35019555 35339540 35749483  
36279363 36969266 37259231 37569160  
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