053
FXUS21 KWNC 031951
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT JULY 03 2023
SYNOPSIS: MID-LEVEL HIGH PRESSURE PERSISTS OVER THE SOUTHERN CONTIGUOUS U.S.
(CONUS) DURING WEEK-2, LEADING TO THE POTENTIAL FOR EXCESSIVE HEAT FOR THE
SOUTHERN AND CENTRAL PLAINS. MID-LEVEL LOW PRESSURE OVER THE WEST COAST BRINGS
A CHANCE FOR HEAVY PRECIP TO PORTIONS OF THE NORTHWESTERN CONUS, WHILE A
CUT–OFF LOW OVER THE GREAT LAKES COMBINED WITH ABUNDANT TROPICAL MOISTURE
INCREASES THE RISK FOR HEAVY PRECIPITATION FOR PORTIONS OF THE NORTHEASTERN
CONUS. SNOWMELT SEASON CONTINUES FOR PORTIONS OF THE WEST AFTER EXCEPTIONAL
WINTER ACCUMULATIONS, LEADING TO THE CONTINUED POTENTIAL FOR FLOODING, WHILE
ABNORMALLY DRY CONDITIONS OVER PORTIONS OF WISCONSIN AND LOUISIANA RESULT IN
THE POTENTIAL FOR RAPID ONSET DROUGHT (ROD).
HAZARDS
MODERATE RISK FOR EXCESSIVE HEAT FOR PORTIONS OF THE DESERT SOUTHWEST AND
SOUTHERN ROCKIES, TUE-THU, JUL 11-13.
MODERATE RISK FOR EXCESSIVE HEAT FOR PORTIONS OF SOUTHERN PLAINS, TUE-MON, JUL
11-17.
SLIGHT RISK FOR EXCESSIVE HEAT FOR MUCH OF THE SOUTHERN CONUS, TUE-MON, JUL
11-17.
SLIGHT RISK FOR EXCESSIVE HEAT FOR PORTIONS OF THE NORTHWESTERN CONUS, TUE-WED,
JUL 11-12.
SLIGHT RISK FOR HEAVY PRECIPITATION FOR PORTIONS OF THE OHIO AND MIDDLE
MISSISSIPPI VALLEYS, TUE-SAT, JUL 11-15.
SLIGHT RISK FOR HIGH WINDS FOR PORTIONS OF THE SOUTHERN AND CENTRAL PLAINS,
TUE-MON, JUL 11-17.
POSSIBLE FLOODING FOR PORTIONS OF CALIFORNIA AND NEVADA.
RAPID ONSET DROUGHT RISK ACROSS PORTIONS OF EASTERN TEXAS AND CENTRAL LOUISIANA.
DETAILED SUMMARY
FOR THURSDAY JULY 06 - MONDAY JULY 10:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR TUESDAY JULY 11 - MONDAY JULY 17: ENSEMBLE MODEL SOLUTIONS FROM THE GEFS,
ECMWF, AND CMCE ALL DEPICT POSITIVE 500-HPA HEIGHT ANOMALIES IN EXCESS OF 595
DM PERSISTING OVER THE SOUTHERN CONUS THROUGHOUT THE FORECAST PERIOD. THIS
FAVORS INCREASING TEMPERATURES ACROSS THE SOUTHERN AND CENTRAL CONUS, LEADING
TO THE INCREASED POTENTIAL FOR EXCESSIVE HEAT. THE PROBABILISTIC EXTREMES TOOL
(PET) OF ALL THREE ENSEMBLES AFOREMENTIONED INDICATE AT LEAST A 40% PROBABILITY
OF MAXIMUM TEMPERATURES EXCEEDING THE 85TH PERCENTILE AND AT LEAST 100 DEG F
FOR MUCH OF THE SOUTHERN PLAINS AND THE DESERT SOUTHWEST FOR THE ENTIRE WEEK-2
PERIOD. THE CENTER OF THE POSITIVE HEIGHT ANOMALIES SHIFTS SLIGHTLY EASTWARD IN
MANY MODEL SOLUTIONS, RESULTING IN A SLIGHT REDUCTION OF PROBABILITIES FOR
EXTREME HEAT WEST OF CENTRAL NEW MEXICO AFTER JUL 13. THEREFORE A MODERATE RISK
FOR EXCESSIVE HEAT IS POSTED FOR MUCH OF THE DESERT SOUTHWEST AND SOUTHERN
ROCKIES JUL 11-13, AND FOR PORTIONS OF THE SOUTHERN PLAINS JUL 11-17.
ADDITIONALLY, THE PETS INDICATE AT LEAST A 20% PROBABILITY OF EXCEEDING THE
85TH PERCENTILE FOR MUCH OF THE SOUTHERN CONUS FOR THE WHOLE WEEK-2 PERIOD, AS
WELL AS FOR PORTIONS OF THE NORTHWEST CONUS FOR JUL 11-12. THUS SLIGHT RISKS
FOR EXCESSIVE HEAT ARE POSTED FOR THESE REGIONS AND DATES.
AT THE BEGINNING OF WEEK-2 MULTIPLE MODEL SOLUTIONS CONTINUE TO DEPICT
TROUGHING OVER THE GREAT LAKES, LEADING TO ENHANCED PRECIPITATION FOR THE
NORTHEASTERN CONUS. THE CMCE AND ECMWF PETS BOTH INDICATE AT LEAST A 20%
PROBABILITY OF 3-DAY PRECIPITATION ACCUMULATIONS EXCEEDING THE 85TH PERCENTILE
AND AT LEAST A HALF INCH FOR PORTIONS OF THE OHIO AND MIDDLE MISSISSIPPI
VALLEYS, JUL 11-15, SUPPORTING A SLIGHT RISK FOR HEAVY PRECIPITATION FOR THE
REGION.
WITH BROAD TROUGHING ANTICIPATED OVER THE GREAT LAKES AS WELL AS A SIGNIFICANT
CONTINENTAL-SCALE NORTH-SOUTH TEMPERATURE GRADIENT OVER THE CENTRAL CONUS
DURING WEEK-2, PERIODS OF HIGH WINDS ARE FAVORED FOR PORTIONS OF THE SOUTHERN
AND CENTRAL PLAINS. PETS INDICATE AT LEAST A 20% PROBABILITY OF WIND SPEEDS
EXCEEDING THE 85TH PERCENTILE THROUGHOUT THE FORECAST PERIOD, THUS A SLIGHT
RISK FOR HIGH WINDS IS POSTED FOR PORTIONS OF THE SOUTHERN AND CENTRAL PLAINS
FOR JUL 11-17.
DROUGHT CONCERNS ARE FORECAST TO INCREASE ACROSS PARTS OF EAST TEXAS AND
CENTRAL LOUISIANA AS THE HEAT OF SUMMER BUILDS AND A PERSISTENCE OF
BELOW-NORMAL PRECIPITATION IS FORECAST FOR THE REGION. WHILE THERE SOME
PRECIPITATION IS PREDICTED FOR CENTRAL LOUISIANA IN THE COMING WEEK,
ACCUMULATIONS ARE NOT EXPECTED TO MAKE A SIGNIFICANT DIFFERENCE FROM A SOIL
MOISTURE PERSPECTIVE SO NO CHANGES ARE MADE TO THE ROD OUTLOOK.
SNOWMELT SEASON CONTINUES ACROSS THE WESTERN CONUS AFTER ACCUMULATING A VERY
LARGE AND IN SOME CASES RECORD-BREAKING SNOWPACK, INDUCING RIVER FLOODING
ESPECIALLY ACROSS HIGHER ELEVATIONS FOR SOME AREAS IN THE WEST. AS SNOWMELT
CONTINUES IN PARTS OF THE SIERRA NEVADA, FLOODING MAY CONTINUE TO OCCUR ALONG
SOME RIVERS, AND IN AREAS ADJACENT TO THE HIGHER ELEVATIONS.
FORECASTER: DANNY BARANDIARAN
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