349  
FXUS02 KWBC 220648  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
247 AM EDT THU SEP 22 2022  
 
VALID 12Z SUN SEP 25 2022 - 12Z THU SEP 29 2022  
   
..BREWING TROPICAL ACTIVITY TO MONITOR FROM THE CARIBBEAN
 
 
   
..PATTERN OVERVIEW
 
 
MODELS AND ENSEMBLES AGREE TO BUILD AN AMPLIFIED/WARMING WESTERN  
NORTH AMERICAN UPPER RIDGE THIS WEEKEND INTO NEXT WEEK WITH THE  
DECAY OF A HOT RIDGE OVER THE SOUTHERN TIER U.S.. THIS TRANSITION  
WILL ALLOW ENERGETIC MID-LATITUDE AND NORTHERN STREAM SHORTWAVE  
TROUGHS TO MORE ROBUSTLY DIG DOWNSTREAM TO CARVE OUT AN AMPLIFIED  
EAST-CENTRAL NORTH AMERICAN UPPER TROUGH TO FOCUS COOLER/UNSETTLED  
WEATHER AND OFFER SOME CONNECTION TO POSSIBLE TROPICAL ACTIVITY TO  
MONITOR BY MID-LATER NEXT WEEK.  
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
MODEL AND ENSEMBLE SOLUTIONS REMAIN WELL CLUSTERED SUNDAY INTO  
MONDAY AND A COMPOSITE OF THE GFS/ECMWF/UKMET/CANADIAN ALONG WITH  
THE NATIONAL BLEND OF MODELS (NBM) SEEMS TO PROVIDE A GOOD BASIS  
FOR THE FORECAST DURING THAT PERIOD, WITH ENHANCED DETAIL  
CONSISTENT WITH A PATTERN WITH ABOVE NORMAL FORECAST  
PREDICTABILITY. FORECAST SPREAD AND UNCERTAINTY GROWTH INTO LONGER  
TIME FRAMES AND TROPICAL SYSTEM DIFFERENCES IN PARTICULAR PROMPTED  
A SWITCH TO FORECAST USAGE OF THE ECMWF ENSEMBLE MEAN TO MAINTAIN  
WPC MAX PRODUCT AND NHC PREFERENCE CONTINUITY NEXT WEEK.  
   
..WEATHER/HAZARDS HIGHLIGHTS
 
 
UPPER RIDGE AMPLIFICATION OVER THE WEST WILL SUPPORT GENERALLY DRY  
AND WARMER THAN AVERAGE TEMPERATURES EARLY-MID NEXT WEEK AND SET  
THE STAGE FOR DOWNSTREAM FLOW AMPLIFICATION AS SHORTWAVES ACROSS  
THE NORTH-CENTRAL U.S. AND ENERGY FROM CANADA CARVE OUT A COOLING  
EAST-CENTRAL U.S. TROUGH. THIS UPPER TROUGH AND DEEPENED SURFACE  
LOW WILL COMBINE TO INCREASE LEAD FRONTAL AND WRAP-AROUND RAINFALL  
CHANCES FROM THE GREAT LAKES THROUGH THE  
APPALACHIANS/NORTHEAST/MID-ATLANTIC SUNDAY INTO MONDAY, WITH LAKE  
ENHANCED RAINFALL IN THE WAKE OF SYSTEM PASSAGE INTO TUESDAY. LEAD  
HOT WEEKEND TEMPERATURES OVER PARTS OF THE SOUTH THIS WEEKEND WILL  
THEN BE REFRESHED WITH TRAILING COLD FRONTAL PASSAGE ACROSS MUCH  
OF THE CENTRAL AND EASTERN U.S. AS CANADIAN HIGH PRESSURE BUILDS  
DOWN ACROSS THE BROAD REGION. THE FRONT SHOULD STALL ACROSS THE  
GULF OF MEXICO AND THE FLORIDA PENINSULA WHERE SHOWERS AND STORMS  
MAY INCREASE IN COVERAGE TUESDAY ONWARD WITH POTENTIAL INFLUX OF  
TROPICAL MOISTURE. WPC AND THE NATIONAL HURRICANE CENTER ARE  
CONTINUING TO MONITOR THE TROPICS REGARDING INVEST 98L, WHICH MAY  
FORM INTO A TROPICAL CYCLONE. WHILE THERE IS A THREAT FOR  
IMPACTFUL SYSTEM GENESIS AND POSSIBLE TRACK FROM THE CARRIBEAN TO  
THE GULF OF MEXICO, OPTED FOR NOW TO DECREASE SUBSTANTIAL NBM  
FLORIDA RAINFALL AMOUNTS NEXT WEEK GIVEN UNCERTAINTIES OF TROPICAL  
DEVELOPMENT, TIMING AND STEERING INTERACTION WITH THE DEVELOPING  
EAST-CENTRAL U.S. UPPER TROUGH.  
 
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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