097  
FXUS02 KWBC 091844  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
243 PM EDT MON MAY 09 2022  
 
VALID 12Z THU MAY 12 2022 - 12Z MON MAY 16 2022  
 
...BLOCKY PATTERN FAVORS RECORD HEAT FROM THE SOUTHERN  
PLAINS/LOWER MISSISSIPPI VALLEY TO THE MIDWEST/NORTHEAST ALONG  
WITH EPISODES OF CENTRAL U.S. CONVECTION AND AN EMERGING ONSHORE  
RAINFALL FOCUS TO THE CAROLINAS...  
...EMERGING HEAT THREAT FOR CALIFORNIA AND THE SOUTHWEST BY EARLY  
NEXT WEEK...  
 
   
..OVERVIEW
 
 
THE BLOCKY PATTERN INTO LATER THIS WEEK WILL STILL FEATURE A MEAN  
TROUGH ALOFT OVER THE WEST, AMPLIFIED UPPER RIDGING FROM THE  
SOUTHERN PLAINS THROUGH GREAT LAKES/NORTHEAST, AND AN UPPER LOW  
OFF THE SOUTHEAST COAST. TEMPERATURES WILL LIKELY CHALLENGE DAILY  
RECORDS UNDER AND NEAR THE UPPER RIDGE AXIS LATE THIS WEEK WHILE  
PARTS OF THE WEST WILL SEE CHILLY WEATHER WITH RAIN AND HIGHER  
ELEVATION SNOW. BETWEEN THESE REGIMES, A STORM SYSTEM EMERGING  
OVER THE NORTHERN PLAINS MAY PRODUCE SOME AREAS OF HEAVY RAINFALL  
WHERE WET GROUND CONDITIONS ALREADY EXIST. THEN DURING THE  
WEEKEND AND EARLY NEXT WEEK MOST GUIDANCE SHOWS THE PATTERN  
TRANSITIONING TOWARD A WESTERN RIDGE/EAST-CENTRAL U.S. TROUGH  
CONFIGURATION. THIS EVOLUTION SHOULD FINALLY PUSH THE RAINFALL  
FOCUS TO THE EAST OF THE PLAINS. THE INITIAL UPPER LOW TRACKING  
INTO THE SOUTHEAST AROUND FRIDAY DUE TO A RETROGRADING ATLANTIC  
RIDGE SHOULD QUICKLY LIFT NORTHWARD AND OPEN UP DURING THE  
WEEKEND, WITH ASSOCIATED RAINFALL SPREADING INTO AND NORTH FROM  
THE CAROLINAS. THE RIDGE BUILDING OVER THE WEST WILL LEAD TO  
INCREASING COVERAGE OF VERY WARM TO HOT TEMPERATURES OVER THE  
SOUTHERN HALF OF THE WEST DURING SATURDAY-MONDAY.  
   
..GUIDANCE EVALUATION/PREFERENCES
 
 
THE 06 UTC GFS/GEFS AND 00 UTC UKMET/CANADIAN/ECMWF/ECMWF ENSEMBLE  
MEAN SEEM REASONABLY WELL CLUSTERED INTO DAY 3/4 (THURSDAY/FRIDAY)  
AND A COMPOSITE SOLUTION SEEMS TO OFFERS A GOOD FORECAST BASIS IN  
CONJUNCTURE WITH THE 13 UTC NATIONAL BLEND OF MODELS. THESE  
GFS/ECMWF RUNS, ALONG WITH LATEST 12 UTC VERSIONS, REMAIN BEST  
COMPATIBLE WITH THE GEFS/ECMWF ENSEMBLE MEANS INTO DAYS 5-7 AND  
THIS FAVORED BLEND MAINTAINS GOOD WPC PRODUCT CONTINUITY.  
   
..WEATHER/THREAT HIGHLIGHTS
 
 
THE STRONG UPPER RIDGE EXTENDING FROM THE SOUTHERN PLAINS THROUGH  
THE GREAT LAKES/NORTHEAST AS OF THURSDAY WILL PROMOTE MUCH ABOVE  
NORMAL TEMPERATURES FROM MUCH OF THE PLAINS AND MISSISSIPPI VALLEY  
THROUGH THE GREAT LAKES AND NORTHEAST LATE THIS WEEK.  
HIGHS/MORNING LOWS WILL BE AT LEAST 10-20F ABOVE NORMAL WITH SOME  
EMBEDDED PLUS 20-25F ANOMALIES POSSIBLE FROM THE CENTRAL PLAINS  
INTO GREAT LAKES, AND LOCATIONS ACROSS A FAIRLY BROAD AREA MAY  
CHALLENGE DAILY RECORDS. AFTER FRIDAY EXPECT THE ABOVE NORMAL  
TEMPERATURES TO BE MORE CONFINED TO THE GREAT LAKES/NORTHEAST AND  
THE FAR SOUTHERN PLAINS/WESTERN GULF COAST REGION. THERE WILL BE  
A LINGERING POTENTIAL FOR DAILY RECORDS OVER THE NORTHEAST INTO  
SATURDAY AND OVER EASTERN TEXAS AND VICINITY THROUGH THE END OF  
THE PERIOD.  
 
THE FRONTAL SYSTEM AND UPPER DYNAMICS CROSSING THE NORTHWEST LATE  
THIS WEEK WILL PRODUCE A BRIEF PERIOD OF ENHANCED RAIN AND HIGH  
ELEVATION SNOW AS WELL AS HIGHS 5-15F BELOW NORMAL. MEANWHILE THE  
SOUTHERN PART OF THE WEST SHOULD MODERATE TO SLIGHTLY ABOVE NORMAL  
BY FRIDAY. THEN ARRIVAL OF THE UPPER RIDGE WILL EXTEND THE  
WARMING TREND OVER THE WEST THROUGH THE WEEKEND. HIGHS OF 10-20F  
ABOVE NORMAL SHOULD EXPAND FROM CALIFORNIA EASTWARD FROM SATURDAY  
ONWARD AND SOME LOCATIONS COULD REACH RECORD HIGHS BY  
SUNDAY-MONDAY. NORTHERN AREAS OF THE WEST SHOULD BE CLOSER TO  
NORMAL AND ONE OR MORE FRONTS MAY PRODUCE PERIODS OF LIGHT TO  
MODERATE PRECIPITATION OVER THE PACIFIC NORTHWEST.  
 
LATE THIS WEEK THE SYSTEM EMERGING FROM THE WEST AND DEVELOPING  
OVER THE NORTHERN PLAINS BEFORE TRACKING INTO SOUTHERN CANADA,  
ALONG WITH ASSOCIATED FRONTS, MAY PRODUCE AREAS OF HEAVY RAINFALL  
OVER PARTS OF THE FAR NORTHERN TIER WHERE SOME AREAS ARE QUITE  
SENSITIVE TO ADDED RAIN DUE TO VERY WET GROUND CONDITIONS. THE  
EXPERIMENTAL DAY 4 (THURSDAY-THURSDAY NIGHT) EXCESSIVE RAINFALL  
OUTLOOK SHOWS A SLIGHT RISK AREA OVER PARTS OF NORTHERN NORTH  
DAKOTA AND MINNESOTA WHERE THERE IS THE BEST OVERLAP OF GUIDANCE  
SIGNALS FOR SIGNIFICANT RAIN AND INSTABILITY, ALONG WITH HIGH SOIL  
MOISTURE. DEPENDING ON SYSTEM EVOLUTION, AREAS FARTHER WEST BACK  
TO THE NORTHERN HIGH PLAINS COULD ALSO SEE SIGNIFICANT RAINFALL.  
SOME LOCALLY MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS WILL BE  
POSSIBLE FARTHER SOUTH ALONG THE WAVY TRAILING FRONT (WHICH MAY  
HANG UP FOR ABOUT A DAY AS WESTERN ENERGY CATCHES UP TO IT) BUT SO  
FAR WITH LESS AGREEMENT FOR SPECIFICS. THE STORM PREDICTION  
CENTER IS ALSO MONITORING THE POTENTIAL FOR SEVERE WEATHER, SO  
CHECK THE LATEST OUTLOOKS FOR UPDATED INFORMATION. RAINFALL AND  
THE FOCUSING FRONT SHOULD BECOME MORE PROGRESSIVE FROM SATURDAY  
ONWARD, LEADING TO A DRIER TREND OVER THE PLAINS. RETROGRESSION  
OF THE WESTERN ATLANTIC UPPER LOW INTO THE SOUTHEAST TOWARD THE  
END OF THE WEEK SHOULD SPREAD ENHANCED RAINS INTO THE CAROLINAS  
AND VICINITY BY FRIDAY WITH SOME OF THIS MOISTURE SPREADING  
NORTHWARD ACROSS THE MID-ATLANTIC/NORTHEAST THIS WEEKEND. HIGHEST  
TOTALS SHOULD BE OVER OR NEAR THE EASTERN CAROLINAS. AMOUNTS  
FARTHER NORTH SHOULD TREND LIGHTER DUE TO DECREASING FOCUS OF  
MOISTURE AS THE UPPER LOW OPENS UP WHILE IT LIFTS NORTHWARD.  
 
SCHICHTEL/RAUSCH  
 
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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