611  
FXUS02 KWBC 020658  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
257 AM EDT THU JUN 02 2022  
 
VALID 12Z SUN JUN 05 2022 - 12Z THU JUN 09 2022  
   
..OVERVIEW
 
 
AS THE MEDIUM RANGE PERIOD BEGINS SUNDAY, A TROPICAL DISTURBANCE  
FOR WHICH THE NATIONAL HURRICANE CENTER SHOWS A HIGH CHANCE OF  
DEVELOPMENT SHOULD BE EAST OF THE FLORIDA PENINSULA AND PULLING  
AWAY FROM THE U.S., BUT WITH SOME SHOWERS AND STORMS POSSIBLY  
LINGERING OVER FLORIDA AND POTENTIALLY UP THE SOUTHEAST COAST  
DEPENDING ON HOW CLOSE THE LOW TRACKS TO LAND. MEANWHILE FARTHER  
NORTH, THE LOWER 48 SHOULD SEE A FAIRLY ZONAL PATTERN, BUT WITH  
SHORTWAVES AND SURFACE FRONTAL BOUNDARIES PROVIDING FOCI FOR  
THUNDERSTORMS AND POTENTIAL FOR HEAVY RAINFALL OVER MUCH OF THE  
CENTRAL U.S. AND POSSIBLY INTO THE EAST.  
 
   
..MODEL GUIDANCE EVALUATION/PREFERENCES
 
 
MODEL GUIDANCE GENERALLY AGREES THE TROPICAL LOW WILL BE CENTERED  
EAST OF FLORIDA BY SUNDAY MORNING, THOUGH ITS EFFECTS MAY BE  
LINGERING. THE 12Z CMC WAS A FAST SOLUTION WHILE THE NEWER 00Z CMC  
HAS SLOWED DOWN, EVEN SLOWER THAN OTHER GUIDANCE, SO THE EXACT  
TIMING IS STILL UNCERTAIN. THE ECMWF HAS BEEN PERSISTENTLY THE  
DEEPEST WITH THE LOW, AND THUS SHOWS MORE INFLUENCE IN THE  
MIDLEVELS WITH A CLOSED 500MB LOW AT TIMES. THE EC HAS ALSO  
INDICATED A SLIGHTLY FARTHER NORTH TRACK WITH THE GFS RUNS FARTHER  
SOUTH. A COMPOSITE BLEND OF THE DETERMINISTIC GUIDANCE SEEMS TO  
SHOW A GOOD COMPROMISE SOLUTION.  
 
OTHER THAN THAT FEATURE, THE PATTERN OVER THE U.S. SHOULD BE  
FAIRLY ZONAL WITH SHORTWAVES DOMINATING THE FLOW, SPINNING OFF  
FROM AN UPPER LOW OFFSHORE BRITISH COLUMBIA AND ANOTHER UPPER LOW  
INITIALLY IN SOUTH-CENTRAL CANADA THAT WILL GRADUALLY LIFT  
NORTHEASTWARD THROUGH NEXT WEEK. MODEL GUIDANCE IS REASONABLY  
AGREEABLE WITH THE OVERALL PATTERN, AND IS EVEN NOT TOO BAD WITH  
INDIVIDUAL SHORTWAVES THROUGH MIDWEEK. PREVIOUS MODEL CYCLES OF  
THE GFS IN PARTICULAR WERE SHOWING SOME PHASING OF ENERGY AROUND  
THE NORTHERN HIGH PLAINS THROUGH TUESDAY AND BEYOND, BUT NOW THE  
GFS/ECMWF/CMC ARE MORE AGREEABLE WITH LOW AMPLITUDE RIDGING THERE  
TUESDAY IN BETWEEN SHORTWAVE FEATURES. THESE SHIFT EASTWARD  
WEDNESDAY-THURSDAY AND THE UPSTREAM SHORTWAVE DOES END UP CAUSING  
SOME DIFFERENCES IN THE DEPTH OF TROUGHING ACROSS THE EAST-CENTRAL  
U.S. BY THURSDAY, WITH THE 12Z GFS AMONG THE STRONGEST. MEANWHILE  
MODELS ALSO SHOW GOOD CONSENSUS FOR SOUTHERN TIER RIDGING, WITH  
SOME TYPICAL TIMING AND MODEL VARIATIONS WITH OCCASIONAL CLOSED  
HIGHS. THUS A BLEND OF THE 12Z/18Z GFS RUNS AND THE 12Z ECMWF,  
CMC, AND UKMET ALSO WORKED WELL FOR THE CONUS FOR THE FIRST HALF  
OF THE MEDIUM RANGE PERIOD, SWAPPING THE UKMET FOR THE ECMWF MEAN  
DAY 6 AND ADDING IN A SMALL PORTION OF THE GEFS MEAN ON DAY 7 AS  
WELL. OVERALL A BIGGER PERCENTAGE OF OPERATIONAL MODELS THAN  
NORMAL COULD BE MAINTAINED THROUGH THE PERIOD WITH THE REASONABLY  
GOOD CONSENSUS.  
 
   
..SENSIBLE WEATHER/THREAT HIGHLIGHTS
 
 
THOUGH THE BULK OF THE EFFECTS OF THE TROPICAL DISTURBANCE WILL BE  
IN THE SHORT RANGE PERIOD, SOME SHOWERS AND STORMS COULD BE  
PRESENT ACROSS FLORIDA WITH LINGERING MOISTURE AND POSSIBLY REACH  
THE SOUTHEAST COAST. CONTINUED CONVERGENCE ACROSS SOUTH FLORIDA  
AND THE KEYS COULD PROMOTE ADDITIONAL RAIN AND THUNDERSTORMS THERE  
THROUGH AT LEAST THE FIRST HALF OF NEXT WEEK, BUT SCATTERED IN  
NATURE. MEANWHILE A WEAK TO MODERATE ATMOSPHERIC RIVER THIS  
WEEKEND AIMED AT THE NORTHWEST U.S. WILL INCREASE PRECIPITATION  
CHANCES THERE. THIS SHOULD BE MAINLY RAIN AS SNOW LEVELS ARE  
FORECAST TO BE HIGH, WITH CHANCES FOR SNOW ONLY IN THE HIGHEST  
PEAKS OF THE CASCADES AND NORTHERN ROCKIES. PARTS OF THE CENTRAL  
U.S. CAN LIKELY EXPECT THE MOST IMPACTFUL RAIN, HOWEVER.  
MEANDERING FRONTAL BOUNDARIES WILL PROVIDE AREAS OF FOCUS FOR  
ENHANCED RAINFALL WITH CONVECTION IN A PATTERN WITH PLENTY OF  
MOISTURE. THIS LOOKS TO BE MOST LIKELY ACROSS NORTHERN/CENTRAL  
PARTS OF THE PLAINS AND INTO THE MIDDLE MISSISSIPPI VALLEY AND  
POSSIBLY THE LOWER OHIO VALLEY. BUT UNFORTUNATELY, MODELS ARE  
QUITE VARIABLE WITH THE PLACEMENT OF HEAVY RAINFALL BEYOND THAT,  
AS THE AXES OF ENHANCED RAIN WILL BE HIGHLY DEPENDENT ON WHERE  
INDIVIDUAL BOUNDARIES SET UP. THE INGREDIENTS ARE CERTAINLY IN  
PLACE FOR HEAVY RAINFALL THAT COULD CAUSE FLASH FLOODING, BUT THE  
DETAILS OF AREAS WITH THE GREATEST THREAT COULD TAKE INTO THE  
SHORT RANGE TO RESOLVE, SO HELD OFF ON ADDING ANY SLIGHT RISKS TO  
THE EXPERIMENTAL DAY 4-5 EXCESSIVE RAINFALL OUTLOOK FOR NOW AS  
THEY WOULD ALMOST CERTAINLY HAVE TO MOVE AROUND. ADDITIONALLY,  
MODELS HAVE TRENDED HEAVIER WITH RAINFALL MOVING INTO THE  
NORTHEAST AROUND MONDAY-TUESDAY AHEAD OF A COLD FRONT.  
 
EXPECT THE GENERAL PATTERN FOR TEMPERATURES NEXT WEEK TO BE COOLER  
THAN AVERAGE IN THE NORTHERN TIER AND WARMER THAN AVERAGE IN THE  
SOUTHERN TIER. THE NORTHERN PLAINS IN PARTICULAR COULD SEE HIGHS  
10-20F AND LOWS AROUND 10F BELOW AVERAGE WITH PERIODS OF TROUGHING  
ALOFT. MEANWHILE, MUCH OF THE SOUTHERN TIER IS FORECAST TO SEE  
ABOVE NORMAL TEMPERATURES BY AROUND 5-10F BUT REACHING +15F  
ANOMALIES IN TEXAS FOR THE FIRST HALF OF NEXT WEEK GIVEN AN UPPER  
HIGH ALOFT. THE WEST COAST SHOULD BE A BIT COOLER THAN NORMAL OVER  
THE WEEKEND UNDER THE TROUGHING INFLUENCE, BUT MODERATING AND  
WARMING TO ABOVE NORMAL IN CALIFORNIA AND INTO THE GREAT BASIN AND  
SOUTHWEST BY AROUND MIDWEEK.  
 
TATE  
 
ADDITIONAL 3-7 DAY HAZARD INFORMATION CAN BE FOUND ON THE WPC  
MEDIUM RANGE HAZARDS OUTLOOK CHART AT:  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP  
 
WPC MEDIUM RANGE 500MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS,  
QUANTITATIVE PRECIPITATION, EXPERIMENTAL EXCESSIVE RAINFALL  
OUTLOOK, WINTER WEATHER OUTLOOK PROBABILITIES AND HEAT INDICES ARE  
AT:  
 
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST500_WBG.GIF  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST_WBG_CONUS.GIF  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/5KM_GRIDS/5KM_GRIDSBODY.HTML  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/DAY4-7.SHTML  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=ERO  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/WWD/PWPF_D47/PWPF_MEDR.PHP?DAY=4  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/HEAT_INDEX.SHTML  
 

 
 

 
 
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