596  
FXUS02 KWBC 250818  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
318 AM EST SAT JAN 25 2025  
 
VALID 12Z TUE JAN 28 2025 - 12Z SAT FEB 1 2025  
   
..GENERAL OVERVIEW  
 
THE FORECAST PERIOD BEGINS ON TUESDAY WITH A VERY SLOW MOVING  
CLOSED LOW OVER NORTHERN CALIFORNIA, AND BROAD CYCLONIC FLOW ALOFT  
FROM THE NORTHERN PLAINS TO THE NORTHEAST STATES, WITH A SPLIT  
UPPER LEVEL FLOW PATTERN IN PLACE FOR THE BEGINNING OF THE WEEK.  
THE CLOSED LOW ONLY MAKES IT TO EASTERN NEW MEXICO BY FRIDAY, WITH  
A RIDGE AXIS TRYING TO BUILD NORTH AHEAD OF IT ACROSS THE MIDWEST  
AND DEEP SOUTH REGION, AND A TROUGH REMAINING OVER NEW ENGLAND AND  
A SEPARATE TROUGH NEAR THE PACIFIC NORTHWEST. IT APPEARS LIKELY  
THAT SURFACE CYCLOGENESIS WILL TAKE PLACE OVER TEXAS IN RESPONSE  
TO THE APPROACHING UPPER LOW, AND THIS WILL LIKELY FUEL AN INCREASE  
IN RAIN FROM TEXAS TO PORTIONS OF THE DEEP SOUTH FOR THE SECOND  
HALF OF THE WEEK, SOME OF WHICH COULD BE HEAVY.  
   
..GUIDANCE/PREDICTABILITY ASSESSMENT  
 
THE 00Z MODEL GUIDANCE SUITE IS INITIALLY IN GOOD OVERALL SYNOPTIC  
SCALE AGREEMENT ACROSS THE CONTINENTAL U.S. FOR THE BEGINNING TO  
MIDDLE OF THE WEEK. THE GUIDANCE HAS TRENDED EVEN SLOWER WITH THE  
UPPER LOW CROSSING THE SOUTHERN ROCKIES AND EVENTUALLY THE WESTERN  
HIGH PLAINS, WITH THE ENSEMBLE MEANS GENERALLY A LITTLE FASTER THAN  
THE DETERMINISTIC GUIDANCE. THE SURFACE LOW EVOLUTION IS A BIT MORE  
UNCERTAIN, BUT THERE IS A TREND FOR THIS TO BE A LITTLE MORE TO THE  
SOUTH COMPARED TO YESTERDAY'S FORECAST. THE ENSEMBLE MEANS  
ACCOUNTED FOR ABOUT 60% OF THE FORECAST BLEND BY NEXT SATURDAY  
MORNING TO ACCOUNT FOR INCREASING DETERMINISTIC MODEL DIFFERENCES.  
   
..WEATHER/HAZARDS HIGHLIGHTS  
 
THE EVOLUTION OF THE SOUTHERN PLAINS LOW PRESSURE SYSTEM STARTING  
MID-WEEK WILL LIKELY PRODUCE INCREASING SHOWERS AND THUNDERSTORMS  
FROM CENTRAL TEXAS TO THE ARKLATEX REGION, BUT GIVEN MODEL  
DIFFERENCES WITH RESPECT TO LOCATION AND MAGNITUDE, NO RISK AREAS  
ARE CURRENTLY WARRANTED FOR EITHER THE DAY 4 OR DAY 5 EXCESSIVE  
RAINFALL OUTLOOKS. HOWEVER, THIS COULD CHANGE AS SPECIFICS BECOME  
CLEARER IN FUTURE OUTLOOKS. LOOKING BEYOND THE DAY 5 PERIOD, THERE  
HAS BEEN A GENERAL UPWARD TREND IN EXPECTED RAINFALL TOTALS  
COMPARED TO THE PREVIOUS WPC FORECAST OVER THE ARKLATEX REGION TO  
THE WESTERN GULF COAST, WITH THE POTENTIAL FOR 2 TO 4 INCHES FOR  
THIS REGION DURING THE THURSDAY TO FRIDAY TIME PERIOD. SOME STRONG  
THUNDERSTORMS ARE ALSO POSSIBLE DEPENDING ON HOW THE WARM SECTOR OF  
THIS LOW PRESSURE SYSTEM EVOLVES.  
 
ELSEWHERE ACROSS THE NATION, A SWATH OF LIGHT TO MODERATE SNOW IS  
LIKELY FROM NORTHERN MINNESOTA TO NORTHERN NEW ENGLAND TUESDAY INTO  
WEDNESDAY AS A CLIPPER TYPE LOW PRESSURE SYSTEM CROSSES THE REGION.  
LATER IN THE WEEK, RAIN AND MOUNTAIN SNOW IS EXPECTED TO MAKE A  
RETURN TO THE PACIFIC NORTHWEST AS THE NEXT SHORTWAVE TROUGH AND  
SURFACE COLD FRONT MOVES INTO THE REGION, AND THIS COULD REACH MUCH  
OF CALIFORNIA GOING INTO FRIDAY.  
 
MUCH OF THE EAST SHOULD FINALLY BE BACK UP TOWARDS NORMAL  
TEMPERATURES EARLY NEXT WEEK, FOLLOWED BY A RETURN TO COLDER  
READINGS BY THURSDAY INTO FRIDAY AFTER A COLD FRONT MOVES THROUGH.  
ANOMALOUSLY COLD TEMPERATURES ARE EXPECTED ACROSS THE SOUTHWESTERN  
U.S. UNDER THE INFLUENCE OF UPPER TROUGHING/CLOSED LOW, WITH SNOW  
FOR THE MOUNTAINS OF ARIZONA AND NEW MEXICO.  
 
HAMRICK  
 
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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