696
FXUS02 KWBC 261900
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 PM EST SUN JAN 26 2025
VALID 12Z WED JAN 29 2025 - 12Z SUN FEB 02 2025
..SOUTH-CENTRAL U.S. HEAVY RAINFALL THREAT WEDNESDAY-SATURDAY
..GENERAL OVERVIEW
A MAIN WEATHER SYSTEM THIS WEEK WILL BE A SLOW MOVING CLOSED UPPER
LOW WILL LINGER OVER THE SOUTHWEST WEDNESDAY AND THURSDAY, THEN
GRADUALLY EJECT NORTHEAST TOWARDS THE SOUTHERN/CENTRAL PLAINS AND
MIDWEST FRIDAY AND SATURDAY. THIS FEATURE WILL BE ACCOMPANIED BY AN
OCCLUDED LOW PRESSURE SYSTEM AT THE SURFACE THAT COULD BRING A
HEAVY RAINFALL THREAT TO THE SOUTH- CENTRAL U.S. DURING THE SECOND
HALF OF THE WEEK. MEANWHILE, A BROAD UPPER TROUGH WILL SWING ACROSS
THE NORTH- CENTRAL AND NORTHEASTERN U.S. AND RIDGING WILL EXTEND
NORTH INTO THE PACIFIC NORTHWEST. BY FRIDAY, A TROUGH WILL APPROACH
THE WEST COAST AND PUSH A PACIFIC FRONTAL SYSTEM EAST ACROSS THE
WEST NEXT WEEKEND WHILE AN ARCTIC FRONT SINKS SOUTH ACROSS THE
NORTH-CENTRAL U.S..
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODEL GUIDANCE HAS BEEN IN REASONABLE AGREEMENT ON THE OVERALL
PATTERN THROUGH THE END OF THE WEEK, AND TO A LESSER DEGREE BY NEXT
WEEKEND. THERE IS UNCERTAINTY SURROUNDING THE EVOLUTION OF THE MAIN
SOUTHWEST U.S. OCCLUDED SURFACE LOW, AND RECENT GUIDANCE INCLUDING
THE LATEST 12 UTC CYCLE HAS TRENDED MORE PROGRESSIVE EXCEPT FOR
THE GFS. WHILE THE TIMING COULD BE FASTER, CLOSED UPPER LOWS TEND
NOT TO BE. OVERALL, THERE IS STILL GOOD AGREEMENT FOR DEVELOPMENT
OF HEAVY RAINFALL DOWNSTREAM, ESPECIALLY IN THE WARM SECTOR OF THE
SYSTEM OVER THE SOUTH-CENTRAL U.S. LATER THIS WEEK, WITH
EXPECTED STRONG TO SEVERE CONVECTIONS AS PER SPC. THE WPC FORECAST
MODEL BLEND CONSISTS OF A BLEND OF BEST CLUSTERED GUIDANCE OF
EARLIER CYCLE 06 UTC GFS AND 00 UTC ECMWF/UKMET FOR WEDNESDAY TO
FRIDAY. OPTED TO ADD TO THE MIX INPUT FROM THE GEFS/ECMWF ENSEMBLE
MEANS FOR NEXT WEEKEND AMID GENERALLY SLOW FORECAST SPREAD GROWTH.
..WEATHER/HAZARDS HIGHLIGHTS
A SLOW MOVING OCCLUDED LOW PRESSURE SYSTEM IS FORECAST TO MOVE
ACROSS THE SOUTHERN PLAINS WEDNESDAY THROUGH FRIDAY WITH A COLD
FRONT EXTENDING SOUTHWEST INTO MEXICO AND A WARM FRONT LIFTING INTO
THE LOWER MISSISSIPPI VALLEY. WARM, MOIST AIR FROM THE GULF WILL
BE IN PLACE ACROSS THE SOUTH-CENTRAL U.S., SETTING THE STAGE FOR A
MULTI-DAY HEAVY RAINFALL EVENT. THE BEST CHANCE FOR HEAVY RAINFALL
WILL BE IN THE WARM SECTOR AND IN THE VICINITY OF THE TRIPLE POINT
LOW WHERE MOISTURE AND INSTABILITY WILL BE MAXIMIZED, AND THERE
COULD BE POTENTIAL FOR TRAINING/REPEAT CONVECTION AHEAD OF THE
SLOW TRAILING COLD FRONT. HEAVY RAINFALL COULD LEAD TO FLASH
FLOODING CONCERNS ACROSS THE SOUTHERN PLAINS AND LOWER MISSISSIPPI
VALLEY, ESPECIALLY IN THE ARK-LA-TEX REGION DOWN TO THE GULF ON
THURSDAY AND THE CENTRAL GULF COAST STATES FRIDAY INTO SATURDAY.
FOR THE DAY 4/WEDNESDAY EXCESSIVE RAINFALL OUTLOOK, THERE IS A BIT
TOO MUCH UNCERTAINTY IN RAINFALL LOCATION TO INTRODUCE ANY RISK
AREAS AT THIS TIME, BUT THERE STILL COULD BE LIMITED POTENTIAL FOR
HEAVY RAINFALL IN PORTIONS OF TEXAS IN AN EMERGING PATTERN TO
MONITOR. FOR THE DAY 5/THURSDAY EXCESSIVE RAINFALL OUTLOOK, A
BROAD MARGINAL RISK FROM THE SOUTHERN PLAINS TO THE MID/LOWER
MISSISSIPPI VALLEY AND A SLIGHT RISK FOR THE ARK-LA-TEX HAS BEEN
DEPICTED GIVEN THE STRONG SIGNAL FOR HEAVY RAINFALL.
EARLY IN THE PERIOD, A CLIPPER TYPE LOW PRESSURE SYSTEM WILL BRING
A SWATH OF WINTRY WEATHER TO THE GREAT LAKES AND NORTHEAST, WITH
SOME LOCALIZED HEAVY SNOW POTENTIAL. THIS SYSTEM WILL QUICKLY MOVE
EAST, AND A COUPLE DAYS OF DRY WEATHER ARE EXPECTED FOR THE
NORTHERN TIER BEFORE PRECIPITATION ASSOCIATED WITH THE OCCLUDED LOW
REACHES THE AREA. PRECIPITATION CHANCES WILL EXTEND TO THE NORTH
OF THE OCCLUDED SYSTEM, SPREADING TO ENCOMPASS MUCH OF THE EASTERN
THIRD OF THE NATION BY SATURDAY, AND THERE WILL BE A CHANCE FOR
SNOW/ICE ON THE NORTHERN EXTENT OF THE PRECIPITATION SHIELD GIVEN
LINGERING COLD AIR DAMMED IN PLACE. WINTRY WEATHER IS ALSO
ANTICIPATED ON THE BACKSIDE OF THE LOW, AND HEAVY SNOW/ICE WILL BE
POSSIBLE IN NORTHERN NEW MEXICO AND SOUTHERN COLORADO AND THEN
NORTHEASTWARD OUT ACROSS THE CENTRAL U.S INTO THURSDAY AND FRIDAY.
IN THE WEST, PRECIPITATION CHANCES WILL GRADUALLY INCREASE ACROSS
THE REGION LATE WEEK INTO THE WEEKEND AS A PACIFIC FRONTAL SYSTEM
PUSHES INLAND. WIDESPREAD RAIN AND MOUNTAIN SNOW IS EXPECTED, AND
HEAVY SNOWFALL IS FORECAST FOR THE CASCADES AND THE SIERRA INLAND
THROUGH THE NORTHERN ROCKIES. THE GUIDANCE SIGNAL HAS INCREASED
WITH THE DIGGING OF AMPLE UPPER TROUGH/LOW ENERGY DOWN THE COAST.
TEMPERATURES WILL GENERALLY BE NEAR OR ABOVE NORMAL FOR MUCH OF THE
LOWER 48 LATE THIS WEEK INTO THE WEEKEND, BUT THERE WILL BE A FEW
OPPORTUNITIES FOR BELOW NORMAL TEMPERATURES. THE SOUTHWEST WILL
LIKELY BE BELOW NORMAL WEDNESDAY AND THURSDAY UNDER THE INFLUENCE
OF THE CLOSED UPPER LOW. THE NORTHEAST WILL LIKELY BE BELOW NORMAL
WEDNESDAY INTO NEXT WEEKEND IN AS CLIPPER SYSTEMS MOVE THROUGH AND
COLDER AIR SINKS INTO THE REGION. FINALLY, THERE WILL BE A CHANCE
FOR WELL BELOW NORMAL TEMPERATURES IN THE NORTHERN ROCKIES/HIGH
PLAINS NEXT SUNDAY AS AN ARCTIC FRONT SINKS SOUTH OVER THE REGION.
DOLAN/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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