MESOSCALE PRECIPITATION DISCUSSION 0489
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
538 PM EDT THU JUL 13 2017
AREAS AFFECTED...PORTIONS OF THE SOUTHERN HIGH PLAINS
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 132137Z - 140337Z
SUMMARY...THUNDERSTORMS ARE CONGEALING NORTH OF A WAVE OF LOW
PRESSURE IN NORTHEAST NM. HOURLY RAIN RATES UP TO 2" WITH LOCAL
AMOUNTS TO 4" ARE POSSIBLE.
DISCUSSION...A MID-LEVEL LOW NEAR THE FOUR CORNERS IS ENHANCING
DIVERGENCE ALOFT IN AN AREA OF BROADENING CONVECTION IN NORTHEAST
NM. INFLOW AT 850 HPA IS 15-20 KTS FROM THE SOUTH-SOUTHEAST,
NEARLY TRIPLE THE MEAN 850-400 HPA WIND. EFFECTIVE BULK SHEAR IN
THE AREA IS NEAR 20 KTS. PRECIPITABLE WATER VALUES ARE 1.25-1.5"
PER RAP ANALYSES. ML CAPE VALUES ARE 500-1500 J/KG IN THIS
REGION.
THE EXPECTATION IS FOR CONVECTION TO MOVE EAST-NORTHEAST AT ~10
KTS. THE SURFACE BOUNDARY IN THE REGION IS EXPECTED TO SHIFT
SOUTHWARD. HOWEVER, CIN REDEVELOPING IN A FEW HOURS COULD ALLOW
FOR SOME CONVECTIVE ELEVATION THIS EVENING. INFLOW AT 850 HPA IS
EXPECTED TO RAMP UP AFTER 01Z, WHICH COULD LEAD TO CONVECTIVE
EXPANSION AND A PERIOD OF BACKBUILDING WITHIN THE WEAK FLOW
REGIME. THE MESOSCALE GUIDANCE IN GENERAL IS TOO FAR NORTH WITH
THIS ACTIVITY, SO ADJUSTED THEIR SOLUTIONS SOUTHWARD IN CREATING
THE MPD AREA. BECAUSE OF THIS, IT IS UNCLEAR WHETHER OR NOT THE
CONVECTION WILL WIPE OUT THE INSTABILITY POOL BY THIS EVENING.
USED THE COL POINT IN THE LOW-LEVEL FLOW BETWEEN THE NM WAVE AND
THE KS WAVE FOR THE EASTWARD EXTENT OF THE MPD. HOURLY RAIN RATES
UP TO 2", WITH SPOTTY LOCAL MAXIMA TO 4", ARE POSSIBLE WHERE CELLS
MERGE AND/OR BACKBUILD.
ROTH
ATTN...WFO...ABQ...AMA...DDC...PUB...
ATTN...RFC...ABRFC...WGRFC...
LAT...LON 38200287 37800049 37179999 36030263 35250484
35410551 37500476
Last Updated: 538 PM EDT THU JUL 13 2017