308  
FXUS02 KWBC 121857  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
257 PM EDT TUE JUL 12 2022  
 
VALID 12Z FRI JUL 15 2022 - 12Z TUE JUL 19 2022  
 
...UNCERTAIN EXCESSIVE RAINFALL THREAT FOR THE CENTRAL GULF COAST  
STATES...  
 
19Z UPDATE: THERE IS GOOD OVERALL SYNOPTIC SCALE AGREEMENT IN THE  
12Z MODEL GUIDANCE SUITE THROUGH ABOUT SATURDAY NIGHT. GIVEN THE  
LACK OF A WELL DEFINED SURFACE LOW SIGNAL IN THE GUIDANCE ACROSS  
THE CENTRAL GULF COAST REGION, A WEAK SURFACE TO MID LEVEL TROUGH  
AXIS WILL REMAIN THE MORE UNCERTAIN ASPECT OF THE FORECAST FOR THE  
END OF THE WEEK AND INTO THE WEEKEND. THE MAJORITY OF THE HEAVY  
RAINFALL REMAINS LIKELY DURING THE SHORT RANGE FORECAST PERIOD,  
BUT THERE SHOULD BE ENOUGH HEAVY SHOWERS AND STORMS NEAR THE COAST  
TO MAINTAIN THE SLIGHT RISK AREA FOR EXCESSIVE RAINFALL ON FRIDAY,  
PRIMARILY OWING TO SATURATED GROUNDS FROM EXPECTED HEAVY RAINFALL  
LEADING UP TO FRIDAY. THE MODEL SIGNAL IS WEAKER GOING INTO  
SATURDAY, AND THEREFORE THE SLIGHT RISK AREA FOR SATURDAY ACROSS  
THE SAME GENERAL REGION WAS DROPPED FOR NOW.  
 
ELSEWHERE, MODEL SPREAD BECOMES NOTEWORTHY ACROSS THE NORTHWESTERN  
QUADRANT OF THE NATION GOING INTO EARLY NEXT WEEK WITH THE TROUGH  
AXIS MOVING INLAND FROM THE PACIFIC. THE 12Z CMC BECOMES MORE  
PROGRESSIVE AS THE SYSTEM CROSSES THE NORTHERN ROCKIES, WHEREAS  
THE GFS IS SLIGHTLY AHEAD OF THE SLOWER ECMWF SOLUTION.  
THEREFORE, MORE OF THE GEFS/ECENS, ALONG WITH SOME PREVIOUS WPC  
CONTINUITY, WAS INCORPORATED FOR THE SECOND HALF OF THE FORECAST  
PERIOD. THE PREVIOUS DISCUSSION FOLLOWS BELOW. /HAMRICK  
--------------------  
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
GUIDANCE OVERALL OFFERS A DECENTLY SIMILAR PATTERN EVOLUTION  
THROUGH MEDIUM RANGE TIME SCALES OVER THE CONUS AND A COMPOSITE  
MODEL/ENSEMBLE/NBM SOLUTION SEEMS TO PROVIDE A GOOD FORECAST  
BASIS. THIS INCLUDES FOR UPPER TROUGH ENERGIES BREAKING INLAND  
INTO THE PACIFIC NORTHWEST THROUGH THE PERIOD AS WELL AS FOR AN  
UPPER TROUGH OVER THE EAST TO BE REINFORCED SOME LATE WEEK INTO  
THE WEEKEND AS A SHORTWAVE TROUGH DIGS TO THE LEE OF A  
BUILDING/HOT WEST-CENTRAL U.S. UPPER RIDGE.  
 
A NOTABLE EXCEPTION WITH HIGH UNCERTAINTY REMAINS ALONG THE  
CENTRAL GULF COAST WHERE SOME UPPER LEVEL ENERGY MAY BE LEFT  
BEHIND THIS WEEK WHERE A COL MAY EXIST ALOFT, BUT THE EVOLUTION  
HAS BECOME INCREASINGLY IN QUESTION. SOME GUIDANCE (MOST NOTABLY  
EARLIER RUNS OF THE ECMWF AND UKMET) WANT TO BLOSSOM THIS INTO A  
FAIRLY WELL DEFINED TROPICAL LOW, AND NHC IS MONITORING IN THEIR  
OUTLOOK. HOWEVER, THERE IS SIGNIFICANT UNCERTAINTY WHERE THIS MAY  
FOCUS COASTAL IMPACT FROM LOUISIANA TO THE FLORIDA PANHANDLE.  
RECENT GFS, CMC AND ICON MODELS AND NOW THE 00 UTC ECMWF ARE LESS  
ENTHUSIASTIC WITH SYSTEM DEVELOPMENT, BUT DO SHOW MORE ORGANIZED  
EJECTING PIECES OF ENERGY INLAND ACROSS THE SOUTHEAST/FL. THE 00  
UTC UKMET STILL HAS THE LOW. WPC QPF STILL FOCUSES ACTIVITY ON THE  
CENTRAL GULF COAST CONSIDERING CONTINUITY AND COLLABORATED NHC  
SYSTEM PREFERENCES, BUT DID TREND QPF AMOUNTS DOWNWARD. PLEASE  
REFER TO THE LATEST TROPICAL WEATHER OUTLOOKS FROM NHC FOR THE  
LATEST INFORMATION ON THIS FEATURE.  
 
   
..OVERVIEW AND WEATHER/HAZARDS HIGHLIGHTS
 
 
A HOT UPPER HIGH/RIDGE WILL SETTLE WESTWARD INTO THE FOUR CORNERS  
TO SUPPORT ABOVE NORMAL TEMPERATURES ACROSS MUCH OF THE WEST, BUT  
ALSO WITH WIDESPREAD HEAT TO PERSIST DOWNSTREAM ACROSS THE CENTRAL  
U.S. AS RIDGING/HEIGHTS BUILD OVER THE REGION. IN THIS PATTERN,  
MODEST MONSOONAL MOISTURE FLOW ACROSS THE SOUTHWEST INTO THE GREAT  
BASIN/ROCKIES UNDER THE UPPER RIDGE MAY OFFER DAILY CHANCES FOR  
SHOWERS WITH SOME LOCALLY HEAVIER DOWNPOURS WITH SLOWED CELL  
MOTIONS. MEANWHILE, A SERIES OF UNCERTAIN IMPULSES WILL ROUND THE  
TOP OF THE RIDGE TO PERIODICALLY FOCUS STRONG CONVECTION LOCALLY  
OVER THE NORTH-CENTRAL PLAINS/UPPER MIDWEST, BUT RAINS MAY PROVE  
MORE PROGRESSIVE IN NATURE.  
 
UPPER TROUGH POSITIONS WILL SANDWICH THE UPPER RIDGE, BOTH INTO  
THE PACIFIC NORTHWEST WHERE RAINFALL CHANCES ARE LIMITED AND ALSO  
THE EAST WHERE FRONTS WILL FOCUS SOME RAIN AND THUNDERSTORMS.  
MOISTURE WILL POOL FROM THE EASTERN MID-ATLANTIC TO THE SOUTHEAST  
AND GULF COAST STATES. POSSIBLE SUB-TROPICAL/TROPICAL INTERACTION  
OVER THE NORTHERN THE GULF OF MEXICO MAY SUPPORT HEAVY RAIN  
POTENTIAL INTO THE CENTRAL GULF COAST AND VICINITY AS SLOW-MOVING  
AND REPEAT CELLS WITH VERY HEAVY DOWNPOURS LEAD TO LOCAL RUNOFF  
ISSUES. A "SLIGHT" RISK AREA WAS ISSUED ON THE EXPERIMENTAL WPC  
MEDIUM RANGE EXCESSIVE RAINFALL OUTLOOK THROUGH MID-LATE WEEK.  
MODELS OFFER POTENTIAL FOR A DISTURBANCE OR TROPICAL LOW, ALTHOUGH  
THERE IS SIGNIFICANT UNCERTAINTY IN THIS PER NHC.  
 
SCHICHTEL  
 
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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