969
AWUS01 KWNH 080959
FFGMPD
LAZ000-ARZ000-TXZ000-081500-
MESOSCALE PRECIPITATION DISCUSSION 0972
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
558 AM EDT SAT AUG 08 2026
AREAS AFFECTED...ARKANSAS INTO FAR NORTHERN LOUISIANA
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 080957Z - 081500Z
SUMMARY...SHOWERS AND THUNDERSTORMS WILL EXPAND ACROSS
SOUTHWEST/SOUTH-CENTRAL ARKANSAS THROUGH LATE MORNING. RAINFALL
RATES OF 2"/HR ARE EXPECTED, WHICH THROUGH SLOW STORM MOTIONS
COULD PRODUCE 2-4" OF RAIN WITH LOCALLY HIGHER AMOUNTS. FLASH
FLOODING IS POSSIBLE.
DISCUSSION...THE REGIONAL RADAR MOSAIC EARLY THIS MORNING SHOWS A
RAPID UPTICK IN THUNDERSTORM ACTIVITY ACROSS SOUTHWEST ARKANSAS.
THIS ACTIVITY IS BLOSSOMING RAPIDLY DOWNSTREAM OF AN MCV EVIDENT
IN THE GOES-E PROXYVIS SATELLITE IMAGERY, WITH THE RAPID GROWTH
DRIVING A COINCIDENT INCREASE IN LIGHTNINGCAST PROBABILITIES. THIS
SUGGESTS THAT CONVECTION WILL CONTINUE TO STRENGTHEN THE NEXT FEW
HOURS, SUPPORTED BY AN IMPRESSIVE OVERLAP OF PWS MEASURED VIA GPS
OF AROUND 2 INCHES AND MUCAPE OF 1000 J/KG. DESPITE THIS
CONVECTION BEING QUITE FRESH, HOURLY RAINFALL IN EXCESS OF 1 INCH
HAS ALREADY BEEN MEASURED BY MRMS, ADDITIONALLY SUGGESTIVE OF THE
FAVORABLE ENVIRONMENT IN PLACE.
THE HIGH-RES CAMS ARE STRUGGLING WITH THIS EARLY ACTIVITY, AS BOTH
THE HRRR AND RRFS ARE COMPLETELY MISSING THIS NEW DEVELOPMENT.
HOWEVER, THERE IS A SIGNAL IN BOTH ARWS WHICH IS TRANSLATING TO A
REASONABLE SOLUTION IN THE HREF BLENDED-MEAN QPF SUGGESTING 2-4"
OF RAIN WITH LOCALLY HIGHER AMOUNTS ABOVE 5" POSSIBLE (10-20%
CHANCE FROM THE HREF). THIS WILL BE DUE TO THE ANTICIPATED
EXTREMELY SLOW MOVEMENT OF THE CONVECTION AS MEAN 0-6KM WINDS
REMAIN JUST AROUND 5-10 KTS.
850MB INFLOW IS MODEST AT JUST 10-15 KTS AS REFLECTED BY BOTH THE
SPC RAP ANALYSIS AND REGIONAL VWPS. HOWEVER, THIS IS STILL
SUFFICIENT TO DRIVE STRONG CONVERGENCE AS IT EXCEEDS THE MEAN WIND
BY ALMOST ALMOST DOUBLE IN SOME PLACES. THE VEERING OF THIS INFLOW
WILL ADDITIONALLY RESULT IN CORFIDI VECTORS BECOMING ALIGNED
AGAINST THE MEAN WIND AND COLLAPSING, WHICH WILL RESULT IN
BACKBUILDING AND TRAINING CELLS WITH NET MOTION APPROACHING 0KTS
AT TIMES, LENGTHENING THE DURATION OF HEAVY RAINFALL.
ANTECEDENT CONDITIONS ARE QUITE DRY (NASA SPORT 0-40CM SOIL
MOISTURE GENERALLY BELOW THE 10TH PERCENTILE) FROM A LACK OF
RECENT RAINFALL, AND 3-HR FFG IS ELEVATED AT 3-4 INCHES. HOWEVER,
THE FAVORABLE SETUP FOR VERY SLOW MOVING STORMS WITH INTENSE RAIN
RATES COULD STILL OVERWHELM SOILS, AT LEAST LOCALLY, LEADING TO
ISOLATED TO SCATTERED INSTANCES OF FLASH FLOODING.
WEISS
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...JAN...LZK...SHV...TSA...
ATTN...RFC...ORN...TUA...NWC...
LAT...LON 35799328 35589182 34759147 33959151 33299200
32869276 32639359 32809436 33699427 35439397
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page