600  
FXUS02 KWBC 151900  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
300 PM EDT WED JUN 15 2022  
 
VALID 12Z SAT JUN 18 2022 - 12Z WED JUN 22 2022  
 
...HEAT OVER THE NORTHERN/CENTRAL PLAINS THROUGH THE WEEKEND  
LIKELY TO SHIFT INTO THE MIDWEST THROUGH SOUTHEAST NEXT WEEK...  
 
   
..OVERVIEW
 
 
A VERY AMPLIFIED UPPER PATTERN WILL BE IN PLACE DURING THE  
WEEKEND, FEATURING A STRONG CENTRAL U.S. RIDGE BETWEEN TROUGHS  
NEAR THE WESTERN AND EASTERN COASTS. THEN FLOW SHOULD STEADILY  
TREND TOWARD A MORE TYPICAL SUMMERTIME REGIME BY NEXT WEDNESDAY  
WHEN THE MAIN AXIS OF WESTERLIES WILL LIKELY ALIGN ACROSS THE  
NORTHERN TIER WHILE BROAD RIDGING (ANCHORED BY A HIGH NEAR THE  
LOWER MISSISSIPPI VALLEY) WOULD COVER A LARGE PART OF THE SOUTHERN  
HALF OF THE LOWER 48. WIDESPREAD HOT TEMPERATURES WILL PREVAIL  
UNDERNEATH THE RIDGE, WITH HIGHS REACHING 100F AS FAR NORTH AS THE  
DAKOTAS DURING THE WEEKEND FOLLOWED BY THE MOST ANOMALOUS HIGH  
TEMPERATURES SHIFTING MORE INTO THE MIDWEST THROUGH SOUTHEAST  
DURING THE EARLY/MIDDLE PART OF NEXT WEEK. THE AMPLIFIED FLOW  
REGIME IN PLACE THROUGH THE WEEKEND SHOULD PROMOTE AN EARLY  
MONSOON TYPE PATTERN OVER THE FOUR CORNERS STATES ALONG WITH  
MOISTURE AND RAIN CHANCES IN THE NORTHWEST. FARTHER EAST, THERE  
WILL BE POTENTIAL FOR RAIN AHEAD OF A WARM FRONT ADVANCING INTO  
THE GREAT LAKES/NORTHEAST AND SCATTERED DIURNAL SHOWERS AND STORMS  
ACROSS FLORIDA.  
 
   
..GUIDANCE/PREDICTABILITY EVALUATION
 
 
THE LATEST MODELS AND ENSEMBLE MEANS MAINTAIN GOOD AGREEMENT FOR  
THE LARGE SCALE PATTERN EVOLUTION THROUGH THE PERIOD. SOLUTIONS  
DEVELOP TYPICAL SPREAD FOR THE UPPER HIGH CENTER (AROUND OR  
STRONGER THAN 594DM) EXPECTED TO SETTLE OVER OR NEAR THE LOWER  
MISSISSIPPI VALLEY BY THE MIDDLE OF NEXT WEEK, AND CONTINUE TO  
VARY WITH SOME OF THE DETAILS AND TIMING OF WESTERN U.S. UPPER  
TROUGH/LOW ENERGY EJECTING INTO SOUTHERN CANADA. THE 00Z UKMET WAS  
PARTICULARLY FAST WITH AT LEAST THE NORTHERN CONCENTRATION OF  
ENERGY INTO CENTRAL CANADA AND THUS FAST/EAST WITH AN ASSOCIATED  
SURFACE LOW THERE, THOUGH OVER THE U.S. WITH THE SOUTHERN ENERGY  
LOOKED REASONABLE. ANOTHER WEAKER ROUND OF ENERGY WILL KEEP A  
PROBABLY LOW AMPLITUDE MEAN TROUGH ALONG THE WEST COAST, WITH CMC  
RUNS GENERALLY THE STRONGEST SOLUTIONS. WITHIN THE TROUGH NEAR THE  
EAST COAST, THERE IS STILL SOME INDECISION AS TO THE TIMING OF THE  
FORMATION AND THE LOCATION OF AN EMBEDDED UPPER LOW WHICH IS MOST  
LIKELY TO BE OVER OR NORTH/NORTHEAST OF MAINE DURING THE FIRST  
HALF OF THE PERIOD. LATEST TRENDS SUGGEST THAT THE UPPER TROUGH  
COULD DEPART FROM THE NORTHEAST A LITTLE MORE QUICKLY IN RESPONSE  
TO THE FLATTER FLOW UPSTREAM. THE ARRAY OF GUIDANCE GENERALLY  
FAVORED AN INTERMEDIATE/CONSENSUS APPROACH FOR THE UPDATED  
FORECAST, BY WAY OF A 12Z/18Z OPERATIONAL MODEL BLEND WITH MOST  
EMPHASIS ON THE ECMWF AND GFS RUNS TRANSITIONING TO A MODEL/MEAN  
MIX BY THE LATTER HALF OF THE PERIOD. THE RESULTING FORECAST  
PROVIDED REASONABLE CONTINUITY.  
 
   
..SENSIBLE WEATHER/THREAT HIGHLIGHTS
 
 
THE UPPER TROUGH PUSHING INLAND OVER THE WEST AFTER EARLY SATURDAY  
SHOULD BRING LIGHT TO LOCALLY MODERATE RAINFALL TO PARTS OF THE  
NORTHWEST. PRECIPITATION EXTENDING INTO THE NORTHERN ROCKIES  
DURING THE WEEKEND AND PERHAPS INTO MONDAY (SNOW LIKELY LIMITED TO  
HIGHEST ELEVATIONS) COULD BE LOCALLY HEAVY GIVEN THE STRONG  
DYNAMICS AND AVAILABLE MOISTURE CROSSING THE REGION. IT WILL TAKE  
SOME ADDITIONAL TIME TO RESOLVE IMPORTANT DETAILS OF THE UPPER  
LEVEL SYSTEM WHICH WILL HELP TO REFINE THE FORECAST, WHICH  
CURRENTLY SHOWS SPREAD BETWEEN A TYPICAL RAIN EVENT AND POTENTIAL  
FOR HEAVY RAIN CAUSING FLOODING IN PARTS OF THE NORTHWEST. THE  
UNUSUALLY EARLY MONSOON TYPE PATTERN FARTHER SOUTH WILL BRING MUCH  
ABOVE NORMAL MOISTURE FOR THE TIME OF YEAR NORTHWARD THROUGH THE  
FOUR CORNERS STATES AND VICINITY THROUGH THE WEEKEND, SUPPORTING  
AN INCREASE IN COVERAGE AND INTENSITY OF RAINFALL ACROSS THE  
REGION. RAIN/THUNDERSTORMS SHOULD CONTINUE INTO EARLY NEXT WEEK AS  
THE MOISTURE INTERACTS WITH THE FRONT SLOWLY ADVANCING THROUGH THE  
WEST, THOUGH WITH ACTIVITY TENDING TO DECREASE IN THE NORTHWESTERN  
PART OF THE FOUR CORNERS REGION. CURRENTLY THERE ARE MIXED SIGNALS  
OVER HOW MUCH RAINFALL THE INTERACTION OF THIS MOISTURE WITH THE  
WESTERN FRONT ADVANCING INTO THE PLAINS WILL PRODUCE. FARTHER  
EAST, THE EAST COAST/WESTERN ATLANTIC UPPER TROUGH AND POSSIBLE  
EMBEDDED LOW MAY BRING A FEW SHOWERS TO NEW ENGLAND OVER THE  
WEEKEND. THEN AN AREA OF SHOWERS AND THUNDERSTORMS MAY PUSH ACROSS  
THE GREAT LAKES AND POSSIBLY INTO THE NORTHEAST UNDER  
NORTHWESTERLY FLOW ALOFT AND AHEAD OF AN ADVANCING WARM FRONT. THE  
GULF COAST SHOULD SEE A DIMINISHING OF DIURNALLY FAVORED SHOWERS  
AND THUNDERSTORMS INTO THE WEEKEND WHILE THE FLORIDA PENINSULA  
SHOULD SEE MULTIPLE DAYS OF DIURNAL SHOWERS/STORMS FROM THE  
WEEKEND INTO NEXT WEEK AS THE FRONT PUSHING INTO THE SOUTHEAST  
STALLS.  
 
THE MOST ANOMALOUS TEMPERATURES DURING THE PERIOD WILL BE WITH A  
HEAT WAVE ACROSS THE NORTHERN HALF OF THE PLAINS, WITH MOST AREAS  
SEEING A COUPLE DAYS WITH HIGHS REACHING 20-25F ABOVE NORMAL THIS  
WEEKEND. THIS HEAT MAY PIVOT AROUND THE CENTRAL PORTIONS OF THE  
PLAINS WHERE PLUS 10-20F ANOMALIES MAY PERSIST INTO EARLY NEXT  
WEEK. SOME DAILY RECORDS FOR HIGHS AND WARM LOWS WILL BE POSSIBLE,  
WITH EVEN SOME POTENTIAL FOR A FEW MONTHLY RECORDS FOR WARM LOWS,  
GIVEN THAT LOWS IN THE UPPER 70S ARE FORECAST IN PORTIONS OF THE  
NORTH-CENTRAL U.S. A FRONT MOVING INTO THE PLAINS SHOULD START A  
MODEST COOLING TREND/EASTWARD SHIFT OF THE HEAT EARLY NEXT WEEK.  
AS THE HEAT EXTENDS INTO THE MIDWEST THROUGH SOUTHEAST DURING  
MONDAY-WEDNESDAY, PLUS 10-15F OR SO ANOMALIES FOR HIGHS SHOULD  
BECOME COMMON AND MAY CHALLENGE DAILY RECORD HIGHS/WARM LOWS.  
BEFORE NEXT WEEK'S WARMER TREND OVER THE EAST, THE NORTHERN HALF  
OF THE REGION WILL SEE HIGHS 5-10F OR SO BELOW NORMAL THIS  
WEEKEND. ALSO DURING THE WEEKEND, THE UPPER TROUGH CROSSING THE  
WEST WILL BRING THE REGION A COUPLE DAYS OF HIGHS UP TO 10-15F  
BELOW NORMAL. MORE MODERATE COOL TEMPERATURES WILL PREVAIL OVER  
THE WEST ON MONDAY FOLLOWED BY AREAS OF SOMEWHAT ABOVE OR BELOW  
READINGS.  
 
TATE/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  
 
HAZARDS:  
- HEAVY RAIN ACROSS PORTIONS OF THE NORTHERN PLAINS, THE NORTHERN  
ROCKIES, AND THE NORTHERN GREAT BASIN, SUN-MON, JUN 19-JUN 20.  
- HEAVY RAIN ACROSS PORTIONS OF THE SOUTHERN ROCKIES, THE CENTRAL  
ROCKIES, THE CENTRAL GREAT BASIN, AND THE SOUTHWEST, SAT-MON, JUN  
18-JUN 20.  
- FLOODING POSSIBLE ACROSS PORTIONS OF THE MIDDLE MISSISSIPPI  
VALLEY AND THE NORTHERN PLAINS.  
- FLOODING OCCURRING OR IMMINENT ACROSS PORTIONS OF THE UPPER  
MISSISSIPPI VALLEY, THE PACIFIC NORTHWEST, THE NORTHERN ROCKIES,  
THE NORTHERN GREAT BASIN, AND THE NORTHERN PLAINS.  
- FLOODING LIKELY ACROSS PORTIONS OF THE NORTHERN PLAINS AND THE  
NORTHERN ROCKIES.  
- EXCESSIVE HEAT ACROSS PORTIONS OF THE SOUTHEAST, THE LOWER  
MISSISSIPPI VALLEY, AND THE SOUTHERN PLAINS, SAT, JUN 18 AND  
MON-WED, JUN 20-JUN 22.  
- EXCESSIVE HEAT ACROSS PORTIONS OF THE CENTRAL PLAINS, THE LOWER  
MISSISSIPPI VALLEY, THE CENTRAL APPALACHIANS, THE TENNESSEE  
VALLEY, THE GREAT LAKES, THE MIDDLE MISSISSIPPI VALLEY, THE  
MID-ATLANTIC, THE SOUTHERN APPALACHIANS, THE UPPER MISSISSIPPI  
VALLEY, THE SOUTHEAST, THE SOUTHERN PLAINS, AND THE OHIO VALLEY,  
MON-WED, JUN 20-JUN 22.  
- EXCESSIVE HEAT ACROSS PORTIONS OF THE CENTRAL PLAINS, THE MIDDLE  
MISSISSIPPI VALLEY, THE LOWER MISSISSIPPI VALLEY, AND THE SOUTHERN  
PLAINS, SAT-WED, JUN 18-JUN 22.  
- EXCESSIVE HEAT ACROSS PORTIONS OF THE NORTHERN PLAINS, SAT, JUN  
18.  
- EXCESSIVE HEAT ACROSS PORTIONS OF THE CENTRAL PLAINS, THE MIDDLE  
MISSISSIPPI VALLEY, THE GREAT LAKES, THE UPPER MISSISSIPPI VALLEY,  
AND THE NORTHERN PLAINS, SAT-MON, JUN 18-JUN 20.  
- EXCESSIVE HEAT ACROSS PORTIONS OF THE SOUTHERN APPALACHIANS, THE  
MID-ATLANTIC, THE CENTRAL APPALACHIANS, AND THE OHIO VALLEY,  
TUE-WED, JUN 21-JUN 22.  
- HIGH WINDS ACROSS PORTIONS OF THE CENTRAL GREAT BASIN,  
CALIFORNIA, THE NORTHERN GREAT BASIN, AND THE SOUTHWEST, SAT, JUN  
18.  
- ENHANCED WILDFIRE RISK ACROSS PORTIONS OF THE CENTRAL GREAT  
BASIN AND THE SOUTHWEST, SAT, JUN 18.  
 
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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