Quantitative Precipitation Forecast
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FOUS30 KWBC 251415
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1014 AM EDT WED MAY 25 2016

...VALID 15Z WED MAY 25 2016 - 12Z THU MAY 26 2016...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
20 WSW ERV 35 SSE COT 40 SSW HBV 55 NNE MMAN 6R6 20 WSW SJT
20 WSW ERV.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
20 E UNO 35 SW CIR 20 WSW HOP 30 W BNA 45 NNE MSL 35 W MSL
25 SE OLV 10 E UTA 25 W UTA 20 SE SGT 20 WSW PBF 35 ENE TXK
25 WSW TXK 25 NNE PRX 20 SW OKM 15 NNW TQH 35 NE ROG 20 E UNO.




...EASTERN OKLAHOMA ACROSS ARKANSAS TO WESTERN TENNESSEE AND
ADJACENT NORTHERN MS...

A PREFERRED STORM/MCS TRACK HAD BEEN ON THE NORTHERN AND EASTERN
PERIPHERY OF A WARM MID LEVEL CAP...AND EACH SUCCESSIVE DAY OF
CONVECTION HAD BEEN SHEDDING DEPRESSIONS IN THE HEIGHT FIELD
DOWNSTREAM INTO THE MID MISSISSIPPI VALLEY. SEE NO REASON FOR THIS
PATTERN TO BREAK TODAY. THE LEADING
DEPRESSION/TROUGH HAD PRODUCED HEAVY RAIN IN AR/MO TUESDAY...AND
THERE ARE SHORT TERM SIGNALS THAT CONVECTION MAY IGNITE AGAIN AS
THE LATEST MESOSCALE CIRCULATION CROSSING AR THIS MORNING REACHES
WESTERN TN EARLY THIS AFTERNOON. THIS AREA HAS REDUCED FLASH FLOOD
GUIDANCE FROM YESTERDAYS RAINS.

THE HEAVIER RAIN AND FLASH FLOOD POTENTIAL SHOULD REMAIN ACROSS
EASTERN OK TO AR. IN ADDITION TO THE COMPLEX THIS MORNING WITH THE
GFS SHOWING A DEFINED 700 MB WAVE AND ASSOCIATED CONVERGENCE
MAXIMA TRIGGERING ACTIVITY IN EASTERN OK TO AR...SEVERAL HIGH RES
MODELS INCLUDING THE 00Z WRF ARW SHOW ADDITIONAL ACTIVITY
DEVELOPING TONIGHT IN AR...WHICH IS VULNERABLE FOLLOWING ROUNDS OF
SHOWERS AND STORMS AND LOCALIZED FLOODING THAT OCCURRED YESTERDAY
AND LAST NIGHT.  OUTFLOW BOUNDARIES FROM CURRENT ACTIVITY IN
NORTHWEST AR AND EASTERN OK WILL BE WATCHED FOR POTENTIAL TO SERVE
AS A LIFTING MECHANISM THIS AFTERNOON/EVENING...WITH THE LAST FEW
RAP RUNS REDEVELOPING BOUNDARY LAYER MOISTURE CONVERGENCE MAXIMA
IN AR.

...SOUTHWEST TEXAS...

RIGHT MOVING SUPERCELLS WILL BE VERY SLOW...WITHIN A REGIME
CHARACTERIZED BY STRONG INSTABILITY AND HIGH MOISTURE
CONTENT...HENCE POTENTIAL FOR HIGH PRECIPITATION SUPERCELLS AND
LOCALLY INTENSE RAIN RATES. COVERAGE OF CELLS PRODUCING A FLASH
FLOOD THREAT MAY BE SPARSE...BUT OPTED TO KEEP CONTINUITY RATHER
THAN DOWNGRADE TO SEE TEXT/MARGINAL. MULTIPLE HIGH RES RUNS
INDICATE SHOWERS AND STORMS DEVELOPING IN NORTHEAST MEXICO AND
CROSSING THE RIO GRANDE TO THE TX SIDE...WITH HIGH MOISTURE
CONTENT AS THE ECMWF/GFS SHOW MOISTURE ADVECTING UP THE RIO GRANDE
AND ACROSS SOUTH TEXAS...SETTING UP GROWING ACTIVITY AT THE END OF
THIS PERIOD AND BEYOND.


...KS/NE/IA/MO...

BROAD BAROCLINICITY HAS BEEN PERSISTENT ALONG THE NORTHERN FRINGES
OF THE CAPPED AIRMASS. THUS...REPEATED CLUSTERS OF DIURNALLY
DRIVEN CONVECTION HAVE TENDED TO ROLL OUT ACROSS SOUTHERN
NE/NORTHERN KS AND INTO ADJACENT IA/MO IN RECENT DAYS. SIMILAR
ACTIVITY IS EXPECTED WEDNESDAY AND WEDNESDAY NIGHT. WE NOTE A
LOCAL MAXIMUM OF MOISTURE TRANSPORT IN THE GFS ACROSS THIS
REGION...BUT AT TIMES THOSE SYNOPTIC SIGNALS HAVE NOT BEEN AS
PREDICTIVE OF ORGANIZED HEAVY RAIN...OWING TO DISRUPTION VIA
CONVECTIVE CLUSTERS AND OUTFLOWS OCCURRING ELSEWHERE. WITHOUT MUCH
CONFIDENCE AS TO THE EXACT PLACEMENT OF CONVECTION IN
NE/KS/IA/MO...AND WHETHER SUCH CONVECTION WOULD OVERLAP WITH WET
ANTECEDENT CONDITIONS...WE STOPPED SHORT OF ADDING A SLIGHT RISK
OF EXCESSIVE RAINFALL HERE...BUT WILL MONITOR TRENDS FOR POSSIBLE
INTRODUCTION.

PETERSEN/BURKE
$$





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