Quantitative Precipitation Forecast
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FOUS30 KWBC 231404
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1004 AM EDT SAT JUL 23 2016

...VALID 15Z SAT JUL 23 2016 - 12Z SUN JUL 24 2016...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
20 NW AAA 25 ESE MIW EBS 15 E ORC 25 S FSD 30 E ABR 25 ENE K46D
15 NNW FAR 10 NW BRD HZX 20 WSW ASX RHI 15 N GRB 25 SSE SBM IGQ
15 NNW TIP 20 NW AAA.


15Z UPDATE...
NO CHANGE TO PREVIOUS OUTLOOK AREA.  LATEST SATL/RADAR DATA SHOWED
SEVERAL STG CONVECTIVE COMPLEXES OVER THE ERN DAKOTAS AS OF 13Z..
ONE OVER CNTL ND AND THE OTHER WITH STGR COLD TOP TEMPS AFFECTING
ERN SD/SW MN NRN IA/ERN NEB.  ADDITIONAL STORMS WERE DVLPG AHEAD
OF THE MORE SRN COMPLEX NEAR E/W WARM FRONTAL BNDRY EXTENDING
TOWARD SW WI..WITHIN AXIS OF 2-3+ THSD MUCAPES.  WITHIN THIS MORE
ACTIVE SRN COMPLEX...RECENT HRRR PARALLEL RUN GUIDANCE SUGGESTED
POTNL FOR LOCALIZED RAINFALL AMOUNTS OF 3 TO 5+ INCHES IN AREAS OF
CELL TRAINING/REGENERATION OVER PARTS OF SRN MN/NRN IA THOUGH
RECENT HRRR EXPERIMENTAL RUN IS NOT QUITE AS AGGRESSIVE WITH
AMOUNTS BUT STILL INDICATES AMOUNTS COULD EXCEED 3 INCHES LOCALLY
IN SOME SPOTS IN A COUPLE HRS...WHICH WOULD SUPPORT THE
CONTINUATION OF THE SLIGHT RISK OF EXCESSIVE RAINS ACRS THIS
REGION.   SULLIVAN  PREVIOUS DISCUSSION FOLLOWS...


NORTHERN PLAINS/UPPER MIDWEST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
REMAINS OF ONGOING CONVECTIVE ACTIVITY ACROSS NE AND THE DAKOTAS
AND THEIR ASSOCIATED OUTFLOW BOUNDARIES ARE EXPECTED TO MARCH
EASTWARD AHEAD OF A LONGWAVE TROUGH.  A NEW COMPLEX IS EXPECTED
ACROSS PORTIONS OF MN, IA, WI, AND PERHAPS NORTHERN IL DURING THE
AFTERNOON AND EVENING HOURS, DRAWING 3000-5000 J/KG CAPES (PER 21Z
SREF MEAN FORECASTS) FROM UNDER A NEARBY CAPPING INVERSION AS
CONVERGENT LOW-LEVEL INFLOW OF 25-50 KTS INTERCEPTS A FRONTAL
BOUNDARY AND/OR RESIDUAL OUTFLOW BOUNDARIES FROM CURRENT
CONVECTION BEFORE TURNING SOUTHEAST TO SOUTH INTO OR ACROSS
NORTHERN IL BY SUNDAY MORNING.  THE MID-LEVEL CAPPING INVERSION
APPEARS MODERATELY SEPARATED FROM THE EXPECTED RAINFALL, OPENING
UP THE POSSIBILITY OF FURTHER TRENDS TO THE SOUTH AS WE GET CLOSER
TO THE HEAVY RAIN EVENT SATURDAY NIGHT.  A GREAT DEAL OF THE
GUIDANCE HAS A SIGNAL FOR LOCAL 3-6" OF RAIN IN THE NEIGHBORHOOD
OF SOUTHWEST WI/NORTHEAST IA.  HOURLY RAIN RATES UP TO 2.5" ARE
POSSIBLE WITHIN THIS MOIST AIR MASS, WHICH COULD OCCUR IN SHORT
TRAINING BANDS, CELL MERGERS, OR WHEREVER MESOCYCLONES/WAVES ON
POTENTIAL CONVECTIVE LINES HOLD UP FORWARD PROPAGATION.  FORWARD
PROPAGATION SHOULD BE IN THE ~20 KT RANGE, THOUGH WITH THIS SORT
OF INSTABILITY AND LOW-LEVEL INFLOW AT PLAY, A SQUALL
LINE/LINEARLY ORIENTED CONVECTION IS POSSIBLE WITH RELATED COLD
POOLS POTENTIALLY SPEED UP MOVEMENT CONSIDERABLY.  AFTER
COORDINATING WITH THE FORECAST OFFICES IN WI AND MN, DECIDED
AGAINST UPGRADING TO A MODERATE RISK NEAR THE IA/WI/MN BORDER DUE
TO FORECAST UNCERTAINTY.  SEE SPC OUTLOOKS FOR THE SEVERE WEATHER
POTENTIAL IN THIS REGION.

ROTH
$$





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