718  
FXUS02 KWNH 290642  
PREEPD  
 
PRELIMINARY EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
241 AM EDT WED OCT 29 2025  
 
VALID 12Z SAT NOV 01 2025 - 12Z WED NOV 05 2025  
 
   
..OVERVIEW
 
 
LATEST GUIDANCE CONTINUES TO ADVERTISE AN AMPLIFIED UPCOMING  
MEDIUM RANGE PATTERN ALOFT, AT LEAST THROUGH THIS WEEKEND, WHICH  
FEATURES MEAN TROUGHING OVER THE EASTERN U.S. AND A BUILDING RIDGE  
OUT WEST. A SHORTWAVE DROPS SOUTHWARD FROM THE UPPER MIDWEST ON  
SATURDAY TO BRING RENEWED AMPLIFIED TROUGHING OVER THE EAST WITH  
LATEST GUIDANCE CONTINUING TO TREND TOWARD MORE STREAM SEPARATION  
WITH A POSSIBLE CUTOFF CLOSED LOW OVER OR NEAR THE GULF COAST BY  
EARLY NEXT WEEK, ALBEIT WITH STILL SIGNIFICANT UNCERTAINTY. THE  
TAIL END OF AN ATMOSPHERIC RIVER WILL KEEP THE NORTHWEST STILL WET  
INTO SATURDAY, BUT DRIER INTO EARLY NEXT WEEK WITH UPPER RIDGING.  
ANOTHER DEEP TROUGH MAY APPROACH THE WEST COAST BY AROUND WEDNESDAY  
OF NEXT WEEK.  
 
   
..GUIDANCE/PREDICTABILITY ASSESSMENT
 
 
THE MAIN FORECAST CONCERN CONTINUES TO BE WITH THE SHORTWAVE  
DROPPING SOUTHWARD FROM THE UPPER MIDWEST INTO SATURDAY, WITH  
POSSIBLE CUTOFF CLOSED LOW DEVELOPMENT OVER THE MISSISSIPPI VALLEY  
TO GULF COAST BY SUNDAY OR MONDAY. LATEST TREND IN THE MODELS  
CONTINUES TO BE FOR THIS SCENARIO, BUT THE CMC CONTINUES TO  
ADVERTISE A GENERAL PROGRESSIVE AMPLIFIED TROUGH THROUGH THE  
REGION. THE ENSEMBLE MEANS ARE MORE AMPLIFIED THAN THE CMC IS BUT  
STILL SOMEWHAT PROGRESSIVE BUT THERE IS ALSO A TON OF SPREAD IN THE  
INDIVIDUAL MEMBERS ADVERTISING BOTH SCENARIOS. THERE IS ALSO  
UNCERTAINTY IN WHETHER ANY SORT OF CLOSED LOW WILL LINGER NEAR THE  
GULF COAST (LIKE THE ECMWF) OR LIFT BACK OFF THE SOUTHEAST COAST  
(LIKE THE GFS). THE WPC FORECAST TONIGHT STUCK CLOSE WITH  
CONTINUITY AND THE GFS/ECMWF SHOWING MORE STREAM SEPARATION, BUT  
DID TREND MORE WITH ENSEMBLE MEANS LATE IN THE PERIOD AMIDST  
SIGNIFICANT UNCERTAINTY. OUT WEST, THERE IS QUESTION ON THE TIMING  
OF THE NEXT TROUGH TOWARDS THE COAST LATE PERIOD AND AN ENSEMBLE  
MEAN BLEND SEEMED TO SUFFICE AS A STARTING POINT.  
 
   
..WEATHER/HAZARDS HIGHLIGHTS
 
 
A DEPARTING STRONG SURFACE LOW OUT OF THE NORTHEAST/CANADIAN  
MARITIMES WILL INDUCE LAKE EFFECT RAINS BEHIND IT. THE SHORTWAVE  
DROPPING THROUGH THE MIDWEST MAY BRING SOME UNCERTAIN LIGHT RAIN  
SHOWERS WITH IT, BUT ADDITIONAL RAINFALL MAY DEVELOP ALONG THE GULF  
COAST WITH WEAK SURFACE LOW DEVELOPMENT ALONG A TRAILING FRONTAL  
BOUNDARY IN THE GULF. RAIN MAY EXPAND IN COVERAGE ACROSS THE  
SOUTHEAST AND EAST COAST EARLY NEXT WEEK, BUT WITH MUCH MORE  
UNCERTAINTY AND HIGHLY DEPENDENT ON THE PATTERN EVOLUTION OVER THIS  
REGION NEXT WEEK.  
 
LOCALLY MODERATE TO HEAVY PRECIPITATION MAY LINGER INTO SATURDAY  
ON THE BACK END OF A MODERATELY STRONG ATMOSPHERIC RIVER INTO THE  
NORTHWEST LATE THIS WEEK. BUT BY SATURDAY, INSTABILITY SHOULD BE  
LESS AND THE BETTER MOISTURE ANOMALIES WILL BE QUICKLY SHIFTING  
EASTWARD SO NO MARGINAL RISK IS PLANNED AT THIS TIME ON THE ERO  
SINCE FRIDAY SHOULD BE THE BIGGER DAY. MOST PRECIPITATION IS  
FORECAST TO STAY RAIN OTHER THAN SNOW IN THE HIGHEST PEAKS OF THE  
OLYMPICS AND THE CASCADES. THE REGION SHOULD TREND DRIER SUNDAY  
WITH POSSIBLY ANOTHER INCREASE IN PRECIPITATION INTO EARLY NEXT  
WEEK AGAIN. ELSEWHERE, THE SOUTHWEST TO THE PLAINS SHOULD STAY  
MOSTLY DRY THROUGH THE PERIOD UNDER THE WARMING RIDGE ALOFT.  
 
MUCH OF THE WEST CAN EXPECT WARMER THAN AVERAGE TEMPERATURES  
UNDERNEATH UPPER RIDGING THROUGH THE PERIOD, EXPANDING INTO THE  
CENTRAL U.S. SUNDAY AND BEYOND. MEANWHILE, THE EAST WILL BE MAINLY  
NEAR OR JUST BELOW NORMAL TEMPERATURES UNDERNEATH MEAN UPPER  
TROUGHING.  
 
SANTORELLI  
 
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 FORECAST (QPF), EXCESSIVE RAINFALL  
OUTLOOK (ERO), WINTER WEATHER OUTLOOK (WWO) PROBABILITIES, HEAT  
INDICES, AND KEY MESSAGES CAN BE ACCESSED FROM:  
 
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  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=OVW  
 

 
 
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