606  
FXUS02 KWNH 080753  
PREEPD  
 
PRELIMINARY EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
353 AM EDT WED OCT 8 2025  
 
VALID 12Z SAT OCT 11 2025 - 12Z WED OCT 15 2025  
 
...TROPICAL MOISTURE TO BRING HEAVY RAINFALL HAZARDS TO PARTS OF  
THE SOUTHWEST THIS WEEKEND...  
 
...GUSTY WIND, COASTAL FLOOD, AND HEAVY RAINFALL THREATS EXPECTED  
ALONG PARTS OF THE CAROLINA AND MID-ATLANTIC COASTS THIS WEEKEND  
AND MAY LINGER THROUGH EARLY NEXT WEEK...  
 
   
..GENERAL OVERVIEW  
 
ACTIVE PATTERN WITH LOW DEVELOPMENT EXPECTED ON BOTH COASTS THIS  
WEEKEND INTO NEXT WEEK. AN UPPER LOW OPENS AS IT CROSSES THE  
PACIFIC NORTHWEST COAST SATURDAY MORNING AND THEN PROGRESSES EAST,  
REACHING THE NORTHERN ROCKIES SUNDAY. THIS IS FOLLOWED BY A SECOND  
UPPER LOW THEN DEVELOPS OVER THE SALISH SEA LATE SUNDAY AND DEEPENS  
AS IT TRACKS DOWN THE COAST TO NORTHERN CALIFORNIA BY TUESDAY  
NIGHT. TROPICAL TROPICAL MOISTURE FROM PRISCILLA AND POTENTIALLY  
THE NEXT EASTER PACIFIC TROPICAL SYSTEM WILL BE DRAWN UP BY THESE  
LOWS/TROUGHS AND LEAD TO WIDESPREAD PRECIPITATION ACROSS THE WEST.  
A COASTAL STORM WILL DEVELOP OFF THE CAROLINA COAST FRIDAY NIGHT  
AND DRIFT UP TOWARD THE MID-ATLANTIC COAST THROUGH THE WEEKEND AND  
MAY LINGER THROUGH EARLY NEXT WEEK. IN BETWEEN THESE SYSTEMS IS  
UPPER-LEVEL RIDGING CENTERED OVER TEXAS WITH AN AXIS THAT EXTENDS  
UP THE GREAT PLAINS SATURDAY THEN SHIFTS EAST TO THE MIDWEST FOR  
SUNDAY THROUGH EARLY NEXT WEEK.  
 
   
..GUIDANCE/PREDICTABILITY ASSESSMENT  
 
THE 00Z GUIDANCE SUITE HAS NOTABLY IMPROVED AGREEMENT ON THE  
PAIR OF NORTHWEST LOWS/TROUGHS, THE CENTRAL U.S. RIDGING, AND THE  
DEVELOPING EAST COAST LOW (AND IT'S INTERACTION WITH A NORTHERN  
STREAM LOW FROM THE MIDWEST). THE 12Z/18Z SUITE WAS IN POORER  
AGREEMENT ACROSS THE CONUS, SO THE WPC FORECAST LEANED TOWARD A GFS  
FAVORED GENERAL DETERMINISTIC BLEND FOR DAYS 3/4, THEN THE EC/CMC  
FOR DAYS 5/6 BASED ON THE NORTHWEST TROUGHS/LOWS.  
 
00Z PHYSICAL GUIDANCE TRENDED A BIT SLOWER WITH THE UPPER TROUGH  
TRACKING EAST OVER THE NORTHWEST THIS WEEKEND (WHICH IS IN LINE  
WITH THE EC-AIFS). GUIDANCE IS ALSO IN GOOD AGREEMENT WITH THE  
SUBSEQUENT TROUGH THAT DEVELOPS INTO A LOW SUNDAY NIGHT OVER  
WESTERN WA (ALSO TRENDED TOWARD THE EC-AIFS) THOUGH THE GFS STILL  
HAS A MORE INTERIOR TRACK TO THE OFFSHORE EC/CMC WHICH WERE  
PREFERRED (AND WERE IN AGREEMENT WITH THE EC-AIFS). PRISCILLA  
MOISTURE OVERSPREADS MUCH OF THE INTERMOUNTAIN WEST ON SATURDAY,  
THEN FROM THE NEXT TROPICAL SYSTEM THROUGH SOUTHERN AZ/NM ON  
SUNDAY.  
 
COASTAL CYCLOGENESIS WILL OCCUR OFF THE CAROLINAS FRIDAY NIGHT  
WITH FURTHER DEVELOPMENT AS IT DRIFTS NORTH TO AT LEAST THE  
OUTER BANKS IF NOT THE SOUTHERN MID-ATLANTIC COAST THIS WEEKEND.  
TRACKING UNCERTAINTY IS NOTABLE ON MONDAY WITH THE EC AND EC-AIFS  
FARTHER SOUTH (NEAR NC COAST), THE GFS/UKMET (AND NOW THE 00Z CMC  
WHICH TOOK A MAJOR LEAP NORTHWEST) IN AGREEMENT TO THE NORTH (OFF  
NJ). INTERACTION NOW LOOKS TO TAKE PLACE WITH A NORTHERN STREAM  
LOW TRACKING SOUTHEAST OVER THE GREAT LAKES SATURDAY AND OHIO ON  
SUNDAY. THE GFS/UKMET/CMC HAVE MORE INTERACTION (AND THUS A  
FARTHER NORTH TRACK) THAN THE EC.  
 
   
..WEATHER/HAZARDS HIGHLIGHTS  
 
AN INFLUX OF TROPICAL MOISTURE AHEAD OF PRISCILLA REMNANTS AND AN  
OPENING TROUGH ALONG THE WEST COAST IS EXPECTED ACROSS THE  
INTERMOUNTAIN WEST SATURDAY. STRONG FORCING FROM THE APPROACHING  
TROUGH (ALONG WITH WET ANTECEDENT CONDITIONS) ALLOW FOR A BIT MORE  
OF AN EXPANSION OF THE SLIGHT RISK FOR THE NEW DAY 4 ERO IN  
SOUTHEAST UTAH, NORTHEAST NEW MEXICO AS WELL AS MUCH OF ARIZONA  
AND WESTERN COLORADO. THE TROPICAL MOISTURE SURGE ON SUNDAY IS NOW  
FOCUSED OVER SOUTHERN AZ/NM FOR REMNANTS OF THE SUBSEQUENT TROPICAL  
SYSTEM WHERE A DAY 5 SLIGHT RISK IS RAISED.  
THE NEXT SYSTEM ALONG  
THE WEST COAST SENDS A PLUME OF ENHANCED MOISTURE THROUGH CA MONDAY  
AND TUESDAY. UNDER THESE LOWS/TROUGHS EXPECT MOUNTAIN SNOW.  
 
A LOW OFF THE CAROLINA COAST SATURDAY SENDS A SURGE OF HEAVY RAIN  
THROUGH EASTERN NORTH CAROLINA WHERE A DAY 4 SLIGHT RISK REMAINS IN  
PLACE. THERE IS UNCERTAINTY WITH HOW FAR THE LOW TRACKS, BUT WITH  
THE LIKELIHOOD OF THE LOW CENTER REACHING AT LEAST THE OUTER BANKS,  
THE DAY 5 SLIGHT RISK FOR THE SOUTHERN AND CENTRAL MID-ATLANTIC  
(ROUGHLY SOUTH FROM ATLANTIC CITY NJ TO THE OUTER BANKS WITH  
COORDINATION WITH WFOS MHX, AKQ, AND PHI). IN ADDITION TO HEAVY  
RAIN, GUSTY ONSHORE WINDS WILL ALSO ACCOMPANY THIS SYSTEM AND  
SHOULD CAUSE A COASTAL STORM SURGE IN THE CAROLINAS AND MID-  
ATLANTIC DESPITE THE QUARTER MOON PHASE/NEAP TIDES.  
 
COOL CONDITIONS PREVAIL UNDER LOW PRESSURE ALONG THE COASTS (AND  
EXPANDING OVER THE WESTERN U.S. UNDER UPPER TROUGHING) WITH ABOVE  
NORMAL TEMPERATURES IN BETWEEN UNDER UPPER RIDGING. MAX TEMPS REACH  
15 DEGREES ABOVE NORMAL IN THE MIDWEST BY THE MIDDLE OF NEXT WEEK.  
MAX TEMPS OF 15-20 DEGREES ABOVE NORMAL OVER THE GREAT BASIN AND  
CALIFORNIA THROUGH MUCH OF THE PERIOD.  
 
JACKSON  
 
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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