397  
AWUS01 KWNH 170931  
FFGMPD  
TXZ000-COZ000-NMZ000-AZZ000-UTZ000-171530-  
 
MESOSCALE PRECIPITATION DISCUSSION 1312  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
530 AM EDT THU SEP 17 2026  
 
AREAS AFFECTED...EASTERN AZ...CENTRAL AND WESTERN NM...SOUTHWEST  
CO  
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE  
 
VALID 170930Z - 171530Z  
 
SUMMARY...AREAS OF HEAVY SHOWERS AND THUNDERSTORMS WILL CONTINUE  
TO LIFT NORTHWARD THIS MORNING ACROSS THE SOUTHWEST. RAINFALL  
RATES AS HIGH AS 1.5 INCHES/HOUR AND LOCALIZED CELL-TRAINING WILL  
MAINTAIN A REGIONAL THREAT FOR FLASH FLOODING.  
 
DISCUSSION...THE LATEST GOES-W IR SATELLITE IMAGERY SHOWS A  
WELL-DEFINED AND INCREASINGLY ELONGATED SHORTWAVE TROUGH LIFTING  
NORTH ACROSS EASTERN AZ. THIS ENERGY ALONG WITH DEEP LAYER  
SOUTHERLY MOISTURE TRANSPORT AND MODEST INSTABILITY CONTINUES TO  
FOCUS BROKEN COVERAGE OF HEAVY SHOWERS AND THUNDERSTORMS.  
 
MUCAPE VALUES ARE AS HIGH AS 500 TO 1000 J/KG, BUT THE MOISTURE IS  
PARTICULARLY IMPRESSIVE WITH VALUES RUNNING 2 TO 3 STANDARD  
DEVIATIONS ABOVE NORMAL AND GENERALLY IN THE 95TH+ PERCENTILE OF  
CLIMATOLOGY. HIGH WBZ HEIGHTS ALONG WITH THE TRANSPORT OF TROPICAL  
MOISTURE NORTHWARD FROM MAINLAND MEXICO IS FOSTERING VERY  
EFFICIENT RAINFALL ACROSS THE BROADER SOUTHWEST U.S., WITH LOCALLY  
ENHANCED RAINFALL RATES WHERE AREAS OF DEEPER CONVECTION ARE  
SITUATED. RADAR AND SATELLITE DATA SHOWS THE STRONGEST AREAS OF  
CONVECTION GENERALLY OVER CENTRAL NM, BUT SOME DYNAMICALLY  
ENHANCED CONVECTION IS SEEN OVER EASTERN AZ IN CLOSER PROXIMITY  
THE SHORTWAVE ENERGY.  
 
THE LATEST GUIDANCE LIFTS THE SHORTWAVE ENERGY NORTHWARD TOWARD  
THE INTERMOUNTAIN WEST THIS MORNING WHICH WILL BRING MUCH OF THE  
BROKEN CONVECTIVE ACTIVITY NORTHWARD ALONG WITH IT. UPSLOPE FLOW  
AND RELATED OROGRAPHIC ASCENT OVER THE HIGHER TERRAIN, AND  
ESPECIALLY INTO SOUTHWEST CO, WILL BRING AREAS OF HEAVY RAINFALL  
THAT MAY RESULT IN FLASH FLOODING. RAINFALL RATES WITH ANY OF THE  
STRONGER CONVECTIVE ELEMENTS MAY REACH 1.5 INCHES/HOUR, WITH SOME  
LOCALIZED ADDITIONAL RAINFALL TOTALS THROUGH MID-MORNING OF 2 TO 3  
INCHES GIVEN CONCERNS FOR SOME CELL-TRAINING.  
 
A REGIONAL THREAT FOR FLASH FLOODING WILL CONTINUE AS A RESULT,  
AND THIS WILL AGAIN INCLUDE THE HIGHLY SENSITIVE DRY WASH AREAS,  
ALONG WITH BURN SCAR LOCATIONS AND SLOT/BOX CANYONS.  
 
ORRISON  
   
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
 
 
ATTN...WFO...ABQ...EPZ...FGZ...GJT...PSR...PUB...TWC...  
 
ATTN...RFC...FWR...STR...TUA...NWC...  
 
LAT...LON 38710671 38600544 37340481 35200492 32600555  
31830659 31810780 32670844 32900933 32631062  
33511138 34551139 35811081 36620950 38020818  
 
 
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