048  
FXUS21 KWNC 141933  
PMDTHR  
US HAZARDS OUTLOOK  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD  
300 PM EDT JUNE 14 2024  
 
SYNOPSIS: A HEAT WAVE IS FORECAST TO BE ONGOING ACROSS PORTIONS OF THE MIDWEST,  
MID-ATLANTIC, AND NORTHEAST AS WELL AS MUCH OF THE INTERIOR WEST AT THE OUTSET  
OF WEEK-2 ASSOCIATED WITH BROAD MID-LEVEL HIGH PRESSURE OVER MUCH OF THE  
CONTIGUOUS U.S.(CONUS). ENHANCED SOUTHERLY FLOW AND AN INFLUX OF TROPICAL  
MOISTURE FAVOR ELEVATED CHANCES OF HEAVY PRECIPITATION AND POTENTIAL FLOODING  
NEAR THE GULF OF MEXICO COAST, ALTHOUGH THERE IS UNCERTAINTY REGARDING TIMING  
AND COVERAGE OF THE HEAVIEST PRECIPITATION. HIGH TEMPERATURES AND ANTECEDENT  
RAINFALL DEFICITS RESULT IN THE POTENTIAL FOR RAPID ONSET DROUGHT FOR PORTIONS  
OF THE CORN BELT AND MID-ATLANTIC.  
 
HAZARDS  
 
MODERATE RISK OF EXCESSIVE HEAT ACROSS PORTIONS OF THE OHIO VALLEY, NORTHERN  
APPALACHIANS, MID-ATLANTIC, AND NORTHEAST SAT-MON, JUN 22-24.  
 
MODERATE RISK OF EXCESSIVE HEAT ACROSS PORTIONS OF THE CENTRAL GREAT BASIN,  
SAT-TUE, JUN 22-25.  
 
SLIGHT RISK OF EXCESSIVE HEAT ACROSS PORTIONS OF THE CENTRAL AND EASTERN CONUS,  
SAT-WED, JUN 22-26.  
 
SLIGHT RISK OF EXCESSIVE HEAT ACROSS PORTIONS OF THE WESTERN CONUS, SAT-WED,  
JUN 22-26.  
 
MODERATE RISK OF HEAVY PRECIPITATION ALONG THE WESTERN AND CENTRAL GULF OF  
MEXICO COAST, MON-WED, JUN 24-26.  
 
SLIGHT RISK OF HEAVY PRECIPITATION FOR MUCH OF THE GULF COAST AND LOWER  
MISSISSIPPI VALLEY, SAT-THU, JUN 22-27.  
 
SLIGHT RISK OF HEAVY PRECIPITATION ACROSS PORTIONS OF THE NORTHERN PLAINS AND  
UPPER MISSISSIPPI VALLEY, SAT-SUN, JUN 22-23.  
 
SLIGHT RISK OF HIGH WINDS ACROSS PORTIONS OF THE EASTERN ROCKIES, AND THE  
CENTRAL AND SOUTHERN PLAINS, SAT-MON, JUN 22-24.  
 
FLOODING POSSIBLE ACROSS PORTIONS OF THE GULF OF MEXICO COAST.  
 
RAPID ONSET DROUGHT RISK FOR PARTS OF THE EASTERN CORN BELT AND MID-ATLANTIC.  
 
DETAILED SUMMARY  
 
FOR MONDAY JUNE 17 - FRIDAY JUNE 21:  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP  
 
FOR SATURDAY JUNE 22 - FRIDAY JUNE 28: TODAY’S ENSEMBLE SOLUTIONS FROM THE GEFS  
AND ECMWF ARE SHOWING GOOD CONTINUITY WITH YESTERDAY, PARTICULARLY WITH REGARD  
TO THE SPREADING MID-LEVEL RIDGE OVER THE CONUS AT THE OUTSET OF WEEK-2.  
GUIDANCE FROM THE GEFS AND ECMWF PROBABILISTIC EXTREMES TOOLS (PETS) CONTINUE  
TO DEPICT AT LEAST A 40% PROBABILITY OF DAILY MAXIMUM TEMPERATURES EXCEEDING  
THE 85TH PERCENTILE FOR PORTIONS OF THE OHIO VALLEY, MID-ATLANTIC, NORTHERN  
APPALACHIANS AND NORTHEAST ON JUN 22. TODAY’S MODEL SOLUTIONS DO NOT FAVOR A  
WEAKENING OF THIS RIDGE TRANSLATING TO THE PETS INDICATING AT LEAST A 40%  
CHANCE OF TEMPERATURES EXCEEDING HAZARDOUS THRESHOLDS THROUGH THE 24TH.  
THEREFORE, A MODERATE RISK FOR EXCESSIVE HEAT IS POSTED FOR AREAS HIGHLIGHTED  
ABOVE FOR JUN 22-24. BY THE 24TH THE GEFS AND ECMWF SOLUTIONS DIVERGE, WITH  
THE GEFS FAVORING COOLER CONDITIONS THAN THE ECMWF, WHICH MAINTAINS THE HEAT  
OVER THE EAST. THE GEFS SOLUTION IS PREFERRED DUE TO HISTORICAL SKILL IN THE  
REGION WITH RESPECT TO SUMMERTIME EXCESSIVE HEAT. BOTH THE GEFS AND ECWMF PETS  
CONTINUE TO INDICATE AT LEAST A 20% PROBABILITY OF DAILY MAXIMUM TEMPERATURES  
EXCEEDING THE 85TH PERCENTILE FOR A BROADER AREA OF THE CENTRAL AND EASTERN  
CONUS FOR JUN 22-25, ENCOMPASSING MUCH OF THE TENNESSEE VALLEY AND MICHIGAN,  
MID-ATLANTIC, AND NORTHEAST. MUCH OF THE WEST IS ALSO INFLUENCED BY THIS BROAD  
RIDGE, WHICH IS ALSO INDICATED BY THE PETS HAVING WIDESPREAD 20% CHANCES OF  
MAXIMUM TEMPERATURES EXCEEDING THE 85TH PERCENTILE FOR MOST OF THE FORECAST  
PERIOD. THEREFORE, A SLIGHT RISK FOR EXCESSIVE HEAT IS POSTED FOR JUN 22-26 FOR  
MUCH OF THE WESTERN CONUS. ADDITIONALLY, BOTH THE GEFS AND ECMWF PETS INDICATE  
AT LEAST A 40% PROBABILITY OF EXCEEDING THE 85TH PERCENTILE FOR MAXIMUM  
TEMPERATURES FOR THE WASATCH FRONT OF UTAH AND EXTENDING EASTWARD INTO EASTERN  
NEVADA EARLY IN WEEK-2, THUS A MODERATE RISK FOR EXCESSIVE HEAT IS DESIGNATED  
FOR THIS REGION, JUN 22-25.  
 
IN ADDITION TO THE WIDESPREAD POTENTIAL FOR EXCESSIVE HEAT ACROSS LARGE  
PORTIONS OF THE CONUS, ENSEMBLE SOLUTIONS CONTINUE TO DEPICT AN INCREASE IN  
TROPICAL MOISTURE AND CONVECTIVE ACTIVITY OVER THE SOUTHERN GULF OF MEXICO LATE  
IN WEEK-1 AND CONTINUING INTO WEEK-2. TODAY’S SOLUTIONS DISTRIBUTE THE HEAVIEST  
PRECIPITATION ACROSS A BROADER AREA RELATIVE TO YESTERDAY, CONTINUING THE  
INCREASED POTENTIAL FOR HEAVY PRECIPITATION ACROSS MUCH OF THE GULF COAST. THE  
GEFS AND ECMWF PETS DEPICT AT LEAST A 20% PROBABILITY OF 3-DAY PRECIPITATION  
TOTALS EXCEEDING THE 85TH PERCENTILE AND AT LEAST ONE INCH FOR MUCH OF THE GULF  
COAST, JUN 22-27, WITH HIGHER PROBABILITIES AND THE POTENTIAL FOR EXCEEDING 2  
INCHES ACROSS PORTIONS OF THE WESTERN GULF. TODAY’S MODEL SOLUTIONS ARE A  
LITTLE SLOWER TO BRING THE HEAVIEST PRECIPITATION ONSHORE, THEREFORE A MODERATE  
RISK FOR HEAVY PRECIPITATION IS NOW POSTED FOR PORTIONS OF THE WESTERN AND  
CENTRAL GULF COAST FOR JUN 24-26, WITH A SLIGHT RISK FOR HEAVY PRECIPITATION  
EXTENDING FURTHER INLAND AND INCLUDING THE REST OF THE GULF COAST FOR JUN  
22-27. FINALLY, ABUNDANT ANTECEDENT RAINFALL OVER MUCH OF EASTERN TEXAS HAS  
RESULTED IN MOST OF THE AREA RESERVOIRS AT OR NEAR CAPACITY. GIVEN THE  
POTENTIAL FOR HEAVY RAINFALL DURING WEEK-2, A RISK FOR POSSIBLE FLOODING AND  
FLASH FLOODING IS ALSO HIGHLIGHTED FOR THE COASTAL PLAINS OF TEXAS AND  
LOUISIANA.  
 
ENSEMBLE SOLUTIONS DEPICT A CLIPPER SYSTEM POTENTIALLY AFFECTING THE NORTHERN  
TIER EARLY IN THE PERIOD, INCREASING THE LIKELIHOOD FOR HEAVY PRECIPITATION  
ACROSS PORTIONS OF THE UPPER MIDWEST AT THE OUTSET OF WEEK-2. THIS IS  
WELL-INDICATED BY THE ECMWF (AND TO A LESSER EXTENT THE GEFS) PETS, WHICH  
DEPICT AT LEAST A 20% PROBABILITY OF 3-DAY PRECIPITATION TOTALS EXCEEDING THE  
85TH PERCENTILE AND 1 INCH FOR JUN 22-24. THEREFORE A SLIGHT RISK FOR HEAVY  
PRECIPITATION IS POSTED FOR PORTIONS OF THE UPPER MIDWEST AND UPPER MISSISSIPPI  
VALLEY FOR THE DATES INDICATED ABOVE. THE SYNOPTIC PATTERN ALSO FAVORS ENHANCED  
WINDS ALONG THE EASTERN ROCKIES AND WESTERN GREAT PLAINS. THE ECMWF AND GEFS  
BOTH INDICATE HIGH PROBABILITIES (>60%) OF WIND SPEEDS TO REACH AT LEAST 10KT,  
AND THE ECMWF WIND-GUST FORECAST DEPICTS A NEAR-CERTAINTY FOR GUSTS EXCEEDING  
20KT, EARLY IN THE FORECAST PERIOD. A SLIGHT RISK FOR HIGH WINDS IS POSTED FOR  
PORTIONS OF THE EASTERN ROCKIES AND WESTERN PLAINS FOR JUN 22-24 GIVEN THESE  
ENHANCED WIND SIGNALS.  
 
PORTIONS OF THE MID-ATLANTIC FROM NORTHERN VIRGINIA TO SOUTHERN NEW JERSEY, THE  
OHIO VALLEY AND MIDWEST HAVE HAD SUBSTANTIAL PRECIPITATION DEFICITS OVER THE  
LAST MONTH. WITH SOIL MOISTURE DEFICITS ALREADY IN PLACE, AN EXTENDED HEAT WAVE  
FOR THE REGION PREDICTED, AND MINIMAL PRECIPITATION ANTICIPATED THROUGH AT  
LEAST THE MIDDLE OF WEEK-2, THESE AREAS ARE HIGHLIGHTED IN TODAY’S OUTLOOK FOR  
THE POTENTIAL OF RAPID ONSET DROUGHT.  
 
FORECASTER: DANNY BARANDIARAN  
 
 
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