821  
FXUS02 KWBC 250700  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
300 AM EDT FRI OCT 25 2024  
 
VALID 12Z MON OCT 28 2024 - 12Z FRI NOV 01 2024  
 
...HEAVY SNOW THREATS FOR THE WEST/NORTHWEST NEXT WEEK MAY FOCUS  
OVER THE CENTRAL ROCKIES TUESDAY. LEAD CENTRAL U.S. HEAT TO THEN BE  
REPLACED BY A COLD/WINDY POST-FRONTAL AIRMASS AS FROST/FREEZE  
ISSUES SPREAD FROM THE WEST INTO LATER NEXT WEEK...  
 
   
..GENERAL OVERVIEW
 
 
AN AMPLIFIED UPPER-LEVEL TROUGH SET TO DIG INTO THE WEST THIS  
WEEKEND WILL SPREAD HIGHLY UNSETTLED WEATHER ACROSS MUCH OF THE  
WESTERN U.S. EARLY NEXT WEEK TO INCLUDE HIGH-ELEVATION SNOW, GUSTY  
WINDS AND COLDER TEMPERATURES. THIS TROUGH WILL THEN PUSH EASTWARD  
AGAINST EXPANSIVE/WARM CENTRAL TO EASTERN U.S. UPPER RIDGING;  
RESULTING IN A WAVY SHARP FRONT FOR THE MID-SECTION OF THE COUNTRY  
WHERE A MODERATELY HEAVY RAIN EVENT APPEARS TO EMERGE FROM THE  
PLAINS THROUGH THE MISSISSIPPI VALLEY AND MIDWEST BY NEXT MIDWEEK.  
   
..GUIDANCE/PREDICTABILITY ASSESSMENT
 
 
LATEST GFS/ECMWF/UKMET/CANADIAN MODEL GUIDANCE SEEMS WELL CLUSTERED  
THROUGH EARLY TO MID NEXT WEEK AND ENJOYS GOOD ENSEMBLE AND  
NATIONAL BLEND OF MODEL (NBM) SUPPORT, BOLSTERING FORECAST  
CONFIDENCE. A COMPOSITE SOLUTION SEEMS TO WELL MITIGATE LINGERING  
SYSTEM TIMING DIFFERENCES NEXT WEEK, ALBEIT WITH FAVORED SLOW  
TRANSITION FROM THE MODELS TO A BLEND OF THE NBM AND COMPATIBLE  
GEFS/ECMWF ENSEMBLE MEANS. THIS HOLDS GOOD WPC PRODUCT CONTINUITY.  
   
..WEATHER/HAZARDS HIGHLIGHTS
 
 
 
A COLD FRONT ASSOCIATED WITH A DIGGING UPPER-LEVEL TROUGH FROM  
THE PACIFIC WILL INCREASINGLY WORK INLAND OVER THE WEST INTO EARLY  
NEXT WEEK. PERIODS OF RAIN, HIGH- ELEVATION SNOW, WINDY AND COLDER  
CONDITIONS ARE EXPECTED TO OVERSPREAD MUCH OF THE REST OF THE  
WESTERN U.S. THROUGH EARLY NEXT WEEK ALONG/BEHIND THE FRONT, WITH  
HIGH WINDS SET TO IMPACT THE SOUTHERN ROCKIES AND SOUTHERN HIGH  
PLAINS AS THE COLDER AIRMASS DIGS INTO THE REGION. THIS MAY ALSO  
LEAD TO SOME FROST/FREEZE CONCERNS.  
 
MODEST CYCLOGENESIS ACROSS THE CANADIAN PRAIRIES WILL ADVANCE A  
FRONT ACROSS THE NORTHERN PLAINS AND UPPER MIDWEST THROUGH EARLY  
NEXT WEEK. THIS FRONT IS FORECAST TO SHARPEN WITH TIME AS IT  
CONTINUES TO PUSH AGAINST AN EXPANSIVE HIGH PRESSURE SYSTEM  
ANCHORING ACROSS THE EASTERN AND SOUTHERN U.S. SNOW WILL APPEAR TO  
LINGER OVER THE NORTHERN TO CENTRAL ROCKIES AND INTO THE NORTHERN  
HIGH PLAINS BEHIND A LOW PRESSURE WAVE WHERE ACCUMULATING SNOWFALL  
APPEARS LIKELY. AHEAD OF THE SHARPENING FRONT, A LONG FETCH OF  
RETURN FLOW FROM THE GULF OF MEXICO COULD LEAD TO A MODERATE TO  
HEAVY RAIN EVENT TO EMERGE ACROSS THE MID- MISSISSIPPI VALLEY TO  
THE MIDWEST WITH EMBEDDED THUNDERSTORMS BY MIDWEEK NEXT WEEK  
ESPECIALLY IF A LOW PRESSURE WAVY IS ABLE TO CONSOLIDATE ALONG THE  
FRONT. IN THE MEANTIME, PRECIPITATION ASSOCIATED WITH THE NEXT  
PACIFIC SYSTEM IS FORECAST TO MOVE INTO THE PACIFIC NORTHWEST  
DURING MIDWEEK NEXT WEEK.  
 
THE DIGGING TROUGH IN THE WEST WILL BE MIRRORED BY A STAUNCH  
DOWNSTREAM RIDGE OVER THE CENTRAL TO EASTERN U.S. NEXT WEEK. THIS  
RIDGE WILL SUPPORT TEMPERATURES BETWEEN 20-30 DEGREES ABOVE AVERAGE  
ACROSS THE PLAINS ON MONDAY BEFORE SPREADING INTO THE MISSISSIPPI  
VALLEY AND MIDWEST/EAST INTO TUESDAY, WEDNESDAY AND THURSDAY.  
THERE'S ALSO A POTENTIAL FOR WIDESPREAD TEMPERATURE RECORDS TO BE  
TIED OR BROKEN ACROSS FROM ARIZONA TO TEXAS ON SUNDAY FOLLOWED BY  
AN EXPANSION OF THIS INTO THE PLAINS AND UPPER MIDWEST.  
 
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 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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