Quantitative Precipitation Forecast
Issued by NWS

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FOUS30 KWBC 020829
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
429 AM EDT WED SEP 02 2015

...VALID 12Z WED SEP 02 2015 - 12Z THU SEP 03 2015...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


...UPPER MISSISSIPPI VALLEY...

LATEST SATELLITE IR/WV LOOPS SHOW CONTINUED COMPACT MCS
DEVELOPMENT ACROSS THE UPPER MS VALLEY...OUT AHEAD OF A
WELL-DEFINED SHORTWAVE CURRENTLY PROGRESSING THROUGH EASTERN SD
AND NORTHERN NE. THE COMPACT AREA OF UPPER LEVEL FORCING (UPPER
DIVERGENCE) IS INTERSECTING A THERMODYNAMICALLY-RICH
ENVIRONMENT...WITH MUCAPES ON THE ORDER OF 3000+ J/KG...PWS OF
1.5+ INCHES...AND INCREASING LOW LEVEL INFLOW OF 25-35 KTS ABOVE
THE DECOUPLED LAYER (~925 MB). THESE PARAMETERS WILL LIKELY
FURTHER UPSCALE GROWTH THROUGH THE EARLY AM HOURS...WITH THE
STRENGTH/DEPTH OF THE INSTABILITY CAPABLE OF INTENSE RAINFALL
RATES ON THE ORDER OF 2+ INCHES PER HOUR. GIVEN SOME OF THE
INTENSE RAINFALL RATES ALREADY BEING OBSERVED WITHIN THE
DEVELOPING MESOCYCLONE EARLY THIS AM...LOCALIZED SHORT TERM RUNOFF
ISSUES ARE ANTICIPATED CONSIDERING THE CURRENT FFG.

DO EXPECT A DIMINISHING TREND LATER THIS MORNING WITH THE DECAY OF
THE LOW LEVEL JET...HOWEVER...THE MODELS (ESPECIALLY THE MESOSCALE
GUIDANCE) REMAINS ROBUST WITH RE-DEVELOPMENT LATER IN THE DAY WITH
PEAK HEATING OUT AHEAD OF THE SLOW MCV TRACK...THOUGH FEEL THE
GUIDANCE IS TOO FAR NORTH WITH THE HEAVIER QPF. BASED ON THE
CURRENT TRENDS AND ANTICIPATED AREA OF BEST DESTABILIZATION (LESS
MCS DEBRIS TO OVERCOME)...FEEL THE BEST CHANCE FOR LOCALIZED
EXCESSIVE RAINFALL WILL BE ACROSS CEN/SRN WI INTO NORTHERN IL.

HURLEY

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