798  
FXUS04 KWBC 302057  
QPFPFD  
 
QUANTITATIVE PRECIPITATION FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
457 PM EDT WED MAY 30 2018  
 
PRELIM DAY 1, DAY 2 AND DAY 3 QPF DISCUSSION  
VALID MAY 31/0000 UTC THRU JUN 03/0000 UTC  
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR  
 
DAY 1  
   
..UPPER GREAT LAKES AND MIDWEST
 
 
ALBERTO IS EXPECTED TO CONTINUE TRACKING PROGRESSIVELY TO THE  
NORTH, PRODUCING LOCALLY HEAVY AMOUNTS NEAR THE CENTER AS IT  
TRACKS FROM INDIANA ACROSS LOWER MICHIGAN THIS EVENING OVERNIGHT,  
WITH ADDITIONAL MODERATE TO LOCALLY HEAVY AMOUNTS CONTINUING TO  
DEVELOP FURTHER WEST ACROSS WISCONSIN AND MINNESOTA AS MOISTURE  
STREAMING OUT AHEAD OF THE CENTER INTERACTS WITH AN APPROACHING  
NEGATIVELY-TILTED UPPER TROUGH. WPC QPF REFLECTS CONSENSUS OF THE  
12Z HI-RES MODELS, WHICH CONTINUED TO MAINTAIN A GOOD SIGNAL FOR  
1-2 INCH AMOUNTS, WITH LOCALLY HEAVIER AMOUNTS FROM NORTHERN  
INDIANA INTO WESTERN LOWER MICHIGAN THIS AFTERNOON AND EVENING.  
   
..CENTRAL PLAINS TO THE LOWER OHIO AND TENNESSEE VALLEYS
 
 
WHILE SHOWING SOME DIFFERENCES IN THE DETAILS, THE 12Z HI-RES  
MODELS RUNS CONTINUE TO SHOW A GOOD SIGNAL FOR DEVELOPING MODERATE  
TO HEAVY RAINS THIS EVENING-OVERNIGHT AS A SHORTWAVE TROUGH MOVING  
OUT OF THE CENTRAL ROCKIES INTERACTS WITH MOISTURE POOLING ALONG A  
STATIONARY BOUNDARY EXTENDING ALONG THE KANSAS-OKLAHOMA BORDER.  
CONVECTION IS EXPECTED TO WANE THU MORNING AS THE LEAD SHORTWAVE  
MOVES ACROSS THE MID MISSISSIPPI VALLEY BEFORE REDEVELOPING  
FURTHER DOWNSTREAM ACROSS THE LOWER OHIO AND TENNESSEE VALLEYS,  
WITH UPSTREAM ENERGY POSSIBLY SPURRING SOME ADDITIONAL  
REDEVELOPMENT ACROSS THE MID MISSISSIPPI VALLEY LATER IN THE DAY  
AS WELL. WPC QPF GAVE SIGNIFICANT WEIGHTING TO THE HREF MEAN  
THROUGH MOST OF THE PERIOD.  
 
...LOWER GREAT LAKES / UPPER OHIO VALLEY / CENTRAL APPALACHIANS /  
MID ATLANTIC...  
 
AS THE AFOREMENTIONED TROUGH OVER THE UPPER MIDWEST TRANSLATES  
EASTWARD THIS PERIOD, A NORTHWEST-SOUTHEAST ORIENTED BOUNDARY AND  
THE LEADING EDGE OF A VERY MOIST AIRMASS EXTENDING FROM THE  
MID-ATLANTIC FROM THE GREAT LAKES IS EXPECTED TO MOVE NORTH THIS  
PERIOD. GUIDANCE SHOWS DEEP MOISTURE SURGING NORTH ALONG THE  
CENTRAL APPALACHIANS AND MID-ATLANTIC AS THE LOW LEVEL FLOW BACKS  
AHEAD OF THE APPROACHING TROUGH. THIS MOISTURE ALONG WITH  
AFTERNOON HEATING AND THE LARGER SCALE FORCING AFFORDED BY THE  
APPROACHING TROUGH IS EXPECTED TO SUPPORT AND INCREASING THREAT  
FOR MODERATE TO LOCALLY HEAVY AMOUNTS BOTH ALONG THE HIGHER  
TERRAIN AND AHEAD OF A COLD FRONT PUSHING ACROSS THE LOWER GREAT  
LAKES LATE FRI. WPC QPF GAVE SIGNIFICANT WEIGHTING TO THE HREF  
MEAN THROUGH MOST OF THE PERIOD.  
 
...NORTHERN INTERMOUNTAIN WEST / NORTHERN ROCKIES AND HIGH  
PLAINS...  
 
AS AN UPPER LEVEL TROUGH CONTINUES TO AMPLIFY ACROSS THE  
NORTHWEST, A DEVELOPING UPPER JET COUPLET ALONG WITH AMPLE  
MOISTURE ALONG THE LOW TO MID LEVEL BOUNDARY THERE REMAINS A GOOD  
SIGNAL FOR WIDESPREAD LIGHT TO LOCALLY HEAVIER AMOUNTS ACROSS THE  
REGION. WPC QPF REFLECTS A CONSENSUS OF THE HI-RES MODELS HERE AS  
WELL.  
 
DAYS 2/3...  
   
..NORTHERN ROCKIES INTO NORTHERN PLAINS
 
 
A BAROCLINIC ZONE EXTENDING FROM NORTHERN HIGH PLAINS TO GREAT  
BASIN WILL MOVE EASTWARD TO THE UPPER/MIDDLE MISSISSIPPI VALLEY  
INTO THE SOUTHERN PLAINS BY SATURDAY EVENING. AS THE SYSTEM MOVES  
OUT OF THE ROCKIES INTO A PLUME OF MOISTURE WITH PRECIPITABLE  
WATER VALUES OF 1.25 TO 1.00 INCHES OVER THE NORTHERN PLAINS ON  
THURSDAY EVENING INTO FRIDAY EVENING PRODUCING CONVECTION OVER THE  
NORTHERN PLAINS WITH MAXIMUM QPF AMOUNTS RANGING FROM 1.50 TO 2.00  
INCHES. A SECONDARY MAXIMUM WILL DEVELOP UNDER THE ASSOCIATED  
UPPER-LEVEL LOW WITH MAXIMUM QPF AMOUNTS RANGING FROM 1.20 TO 1.00  
INCHES. OVERNIGHT FRIDAY, MOISTURE WILL SURGE INTO THE PLAINS  
WITH PRECIPITABLE WATER VALUES OF 1.50 INCHES AND THE MOISTURE  
INCREASING AGAIN OVER THE MIDDLE MISSISSIPPI VALLEY WITH  
PRECIPITABLE WATER VALUES OF 1.75 INCHES BY SATURDAY EVENING. THE  
SYSTEM WILL PRODUCE MAXIMUM QPF OVER THE CENTRAL PLAINS WITH QPF  
AMOUNTS RANGING FROM 2.20 TO 2.00 INCHES ON FRIDAY EVENING INTO  
SATURDAY EVENING. A SECONDARY MAXIMUM WILL ALSO DEVELOP OVER  
PARTS OF THE NORTHERN PLAINS WITH MAXIMUM QPF AMOUNTS RANGING FROM  
1.75 TO 2.00 INCHES. THE HIGH QPF AMOUNTS ON THURSDAY EVENING  
INTO FRIDAY EVENING AND FRIDAY EVENING INTO SATURDAY EVENING  
PROMPTED THE PLACEMENT OF A SLIGHT RISK OF EXCESSIVE RAINFALL OVER  
THE NORTHERN ROCKIES INTO THE NORTHERN PLAINS AND OVER PARTS OF  
THE NORTHERN/CENTRAL PLAINS.  
 
   
..OZARKS INTO THE NORTHEAST AND THE MID-ATLANTIC
 
 
ANOTHER BAROCLINIC ZONE EXTENDING FROM THE GREAT LAKES INTO THE  
CENTRAL PLAINS WILL MOVE OFF THE NORTHEAST/NORTHERN MID-ATLANTIC  
COAST EXTENDING WESTWARD TO THE MIDDLE MISSISSIPPI VALLEY BY  
SATURDAY EVENING. MOISTURE WILL POOL ALONG THE BOUNDARY WITH  
PRECIPITABLE WATER VALUES RANGING FROM 1.75 TO 1.50 INCHES THROUGH  
SATURDAY EVENING. THE SYSTEM WILL PRODUCE MAXIMUM QPF AMOUNTS  
RANGING FROM 1.25 TO 0.75 INCHES OVER THE SOUTHERN OHIO/TENNESSEE  
VALLEYS ON THURSDAY EVENING INTO FRIDAY EVENING WITH A SECONDARY  
MAXIMUM OVER THE OZARKS WITH MAXIMUM QPF AMOUNTS RANGING FROM 1.00  
TO 0.75 INCHES. AS THE SYSTEM MOVES EAST THE MAXIMUM QPF AMOUNTS  
WILL RANGE FROM 0.75 TO 0.50 INCHES OVER THE MID-ATLANTIC ON  
FRIDAY EVENING INTO SATURDAY EVENING.  
 
   
..FLORIDA
 
 
SHORT WAVE MOVING OVER THE FLORIDA PANHANDLE WILL MOVE INTO  
MOISTURE WITH PRECIPITABLE WATER VALUES RANGING FROM 1.7R TO 2.00  
INCHES. THE ENERGY WILL PRODUCE CONVECTION OVER THE CENTRAL  
PORTION OF THE PENINSULA PRODUCING MAXIMUM QPF AMOUNTS RANGING  
FROM 1.00 TO 1.20 INCHES ON THURSDAY EVENING INT FRIDAY EVENING.  
 
PEREIRA/ZIEGENFELDER  
 
GRAPHICS AVAILABLE AT WWW.WPC.NCEP.NOAA.GOV/QPF/QPF2.SHTML  
 

 
 
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