954  
FXUS02 KWBC 101757  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
156 PM EDT SUN JUL 10 2022  
 
VALID 12Z WED JUL 13 2022 - 12Z SUN JUL 17 2022  
   
..EXCESSIVE RAINFALL THREAT FOR THE CENTRAL GULF COAST STATES
 
 
...GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT...  
 
ONE OF THE BIGGEST AREAS OF UNCERTAINTY IN THE MEDIUM RANGE PERIOD  
REMAINS ALONG THE CENTRAL GULF COAST, WHERE THERE IS GOOD  
AGREEMENT THAT SOME SORT OF UPPER LEVEL ENERGY WILL GET LEFT  
BEHIND BY AN UPPER TROUGH SHIFTING EAST AT THE END OF THE SHORT  
RANGE, BUT THE EVOLUTION OF THAT IS IN QUESTION TOWARDS NEXT  
WEEKEND. OVERNIGHT, SOME OF THE GUIDANCE (MOST NOTABLY THE ECMWF  
AND UKMET) SEEMED TO REALLY WANT TO BLOSSOM THIS INTO A FAIRLY  
WELL DEFINED TROPICAL LOW, AND NHC HAS RECENTLY ADDED THIS AREA  
INTO THEIR OUTLOOK (WITH A LOW CHANCE OF DEVELOPMENT). THERE IS A  
SIGNIFICANT UNCERTAINTY WHERE THOUGH THIS MAY (OR MAY NOT) IMPACT,  
FROM GENERALLY EAST TX TO THE WESTERN FL PANHANDLE. THE GFS, CMC,  
AND ENSEMBLE MEANS ARE MUCH LESS ENTHUSIASTIC BUT STILL SUGGEST  
THE PRESENCE OF AT LEAST A TROUGH OR LINGERING FRONT FOR SOME  
TIME. UNCERTAINTY REMAINS HIGH, AND SO THE WPC PROGS/QPF FAVOR  
SOMETHING CLOSER TO THE ENSEMBLE MEANS AND 13Z NBM UNTIL  
CONFIDENCE INCREASES. PLEASE REFER TO THE LATEST TROPICAL WEATHER  
OUTLOOKS FROM NHC FOR THE LATEST INFORMATION ON THIS FEATURE.  
 
OTHERWISE, THERE IS CONTINUED GOOD AGREEMENT FOR SOME SORT OF  
AMPLIFIED TROUGHING ACROSS THE EAST, AS A WEAK SHORTWAVE SLIDES  
INTO THE PACIFIC NORTHWEST ON WEDNESDAY AND RIDES OVERTOP A STRONG  
CENTRAL U.S. RIDGE THURSDAY-FRIDAY. EVENTUALLY, THIS ENERGY SHOULD  
DROP BACK TOWARDS THE GREAT LAKES SERVING TO REINFORCE TROUGHING  
OVER THE EAST BY LATE PERIOD. TYPICAL LATE PERIOD UNCERTAINTIES  
WITH TIMING AND DETAILS BEGINS TO ARISE BY DAYS 6-7 BOTH IN THE  
EASTERN TROUGH, BUT ALSO WITH A POSSIBLE CLOSED LOW TOWARDS THE  
PACIFIC NORTHWEST COAST NEXT WEEKEND. WITH THE LATTER, THE ECMWF  
IS WEAKER/FASTER TO BRING ENERGY INTO SOUTHWEST CANADA, BUT THE  
CMC AND GFS SHOW A MUCH STRONGER MORE COMPACT CLOSED LOW JUST OFF  
VANCOUVER ISLAND DAY 7.  
 
THE WPC BLEND FAVORED THE DETERMINISTIC MODELS FOR DAY 3-5, BUT  
QUICKLY TRANSITIONED TO A 50/50 ENSEMBLE MEAN/DETERMINISTIC BLEND  
BY 6 AND 7 TO HELP MITIGATE DIFFERENCES IN THE WEST, AS WELL AS  
ALONG THE GULF COAST. OVERALL, THIS APPROACH MAINTAINS GOOD WPC  
CONTINUITY FROM THE PREVIOUS SHIFT.  
   
..OVERVIEW AND WEATHER/HAZARDS HIGHLIGHTS
 
 
A MAIN UPPER HIGH/RIDGE WILL SETTLE WESTWARD INTO THE FOUR CORNERS  
THIS WEEK TO SUPPORT ABOVE NORMAL TEMPERATURES ACROSS MUCH OF THE  
WEST, BUT THE MOST ANOMALOUS HEAT IS FORECAST TO SPREAD DOWNSTREAM  
ACROSS THE NORTH-CENTRAL U.S. AS RIDGING/HEIGHTS BUILD OVER THE  
REGION. IN THIS PATTERN, MONSOONAL MOISTURE FLOW ACROSS THE  
SOUTHWEST INTO THE GREAT BASIN/ROCKIES MAY OFFER DAILY CHANCES FOR  
SHOWERS WITH SOME LOCALLY HEAVIER DOWNPOURS. 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.  
 
UPPER TROUGH POSITIONS WILL SANDWICH THE UPPER RIDGE BOTH OFF THE  
PACIFIC NORTHWEST WHERE RAINFALL CHANCES ARE LIMITED AND ALSO THE  
EAST WHERE FRONTS WILL FOCUS RAIN AND THUNDERSTORMS. MOISTURE WILL  
POOL FROM THE EASTERN MID-ATLANTIC TO THE SOUTHEAST AND GULF COAST  
STATES NEAR A WAVY STALLED LEAD FRONT. INTERACTION WITH A  
SUB-TROPICICAL DISTURBANCE IN THE GULF OF MEXICO MAY IN PARTICULAR  
SUPPORT HEAVY RAIN POTENTIAL NEAR THE CENTRAL GULF COAST. THIS  
COULD FOCUS SLOW-MOVING/REPEAT CELLS WITH VERY HEAVY DOWNPOURS  
LEADING TO LOCAL RUNOFF ISSUES, SO A "SLIGHT" RISK AREA WAS  
MAINTAINED ON THE EXPERIMENTAL WPC MEDIUM RANGE EXCESSIVE RAINFALL  
OUTLOOK FOR WEDNESDAY. SOME OF THE MODELS HINT AT THE POTENTIAL  
FOR THIS DISTURBANCE TO EVOLVE INTO SOMETHING MORE TROPICAL LIKE,  
ALTHOUGH THERE IS SIGNIFICANT UNCERTAINTY IN THIS, WHICH HAS  
IMPLICATIONS FOR HOW MUCH AND WHERE QPF FALLS. REGARDLESS OF  
DEVELOPMENT THOUGH, THERE IS AGREEMENT THAT HEAVY RAINFALL LIKELY  
IMPACTS THE CENTRAL GULF COAST AS MOISTURE INTERACTS WITH THE  
STALLED FRONTAL BOUNDARY.  
 
SANTORELLI/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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