MESOSCALE PRECIPITATION DISCUSSION 0399
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1123 PM EDT SUN JUN 25 2017

AREAS AFFECTED...NORTHWEST TX & SOUTHEAST NM

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 260322Z - 260807Z

SUMMARY...THUNDERSTORMS WITH HEAVY RAIN SHOULD CONTINUE MARCHING
SOUTH AND SOUTHEAST THROUGH 08Z.  HOURLY RAIN RATES TO 2" WITH
LOCAL AMOUNTS TO 4" ARE EXPECTED.

DISCUSSION...THUNDERSTORMS WITH HEAVY RAINFALL ARE FORMING WITHIN
THE WARM ADVECTION PATTERN TO THE NORTHEAST OF A MESOSCALE WAVE
LOCATED IN SOUTHEAST NM.  AN MCV WAS NOTED IN EAST-CENTRAL NM ON
RADAR IMAGERY.  A SPEED MAXIMUM ALOFT ON THE NORTHERN SIDE OF THE
ACTIVITY IS ACTING AS A MECHANISM FOR UPPER DIVERGENCE.  THE
CONVECTION IS MOVING IN THE DIRECTION OF THE 1000-500 HPA GRADIENT
AT SPEEDS SUPPORTED BY THE FORWARD PROPAGATING CONVECTIVE VECTORS,
SOUTHEAST AT ROUGHLY 15-20 KTS.  AN INSTABILITY GRADIENT NEAR THE
101ST MERIDIAN IS HELPING TO HEM IN ACTIVITY ON THE EAST SIDE. 
MUCAPE VALUES OF 500-2000 J/KG LIE ACROSS THE REGION.  INFLOW AT
850 HPA OF 25-30 KTS OUT OF THE EAST-SOUTHEAST IS SEEN ON AREA VAD
WIND PROFILES, NEARLY TRIPLE THE MEAN 850-400 HPA WIND IN THE
REGION, WHICH IS AIDING PRECIPITATION EFFICIENCY.  EFFECTIVE BULK
SHEAR IS 25-35 KTS.  PRECIPITABLE WATER VALUES ARE 0.9-1.4" WITHIN
THIS PORTION OF THE HIGH PLAINS.

THE RAP MASS FIELDS INDICATE SOME VEERING WITH THE WINDS AT 850
HPA WITH TIME WITH SOME STRENGTHENING NOTED.  THIS SHOULD CONTINUE
THE MAIN THUNDERSTORM COMPLEX'S MOVEMENT TO THE SOUTHEAST. 
ULTIMATELY, INSTABILITY WILL BE THE MAIN PROBLEM AS A REGION OF
<500 J/KG MUCAPE SHOULD ACT AS A SOUTHERN BARRIER TO HEAVY RAIN
CONCERNS EITHER BY LEADING TO WEAKENING CONVECTION OR GREATER
FORWARD PROPAGATION.  ALSO, AT SOME POINT THE BREADTH OF THE
THUNDERSTORM ACTIVITY ALONG THE DIRECTION OF PROPAGATION SHOULD
NARROW AS THE COLD POOL CATCHES UP FROM THE NORTHWEST, POSSIBLY
AROUND 06Z, WHICH SHOULD LEAD TO A WANING RAIN THREAT.   UNTIL
THIS HAPPENS, HOURLY RAIN RATES TO 2" AND LOCAL AMOUNTS TO 4"
WOULD THREATEN FLASH FLOOD GUIDANCE VALUES IN THE REGION.  THE 22Z
HRRR EXPERIMENTAL RUN AND 01Z HRRR RUN APPEAR TO HAVE FUTURE
EXPECTATIONS WELL COVERED.  USED A FIVE HOUR WINDOW AS A
PRECAUTION, JUST IN CASE CONVECTIVE EVOLUTION IS NOT AS EXPECTED.

ROTH

ATTN...WFO...ABQ...AMA...LUB...MAF...

ATTN...RFC...ABRFC...WGRFC...

LAT...LON   35530229 35500073 33740059 32770149 31590337
            31480390 32030439 33100457 33790456 34340422
            35180329