884
FXUS02 KWBC 090707
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
207 AM EST THU JAN 9 2025
VALID 12Z SUN JAN 12 2025 - 12Z THU JAN 16 2025
.. ARCTIC AIRMASS TO REINFORCE OVER THE LOWER 48 NEXT WEEK
..PATTERN OVERVIEW AND GUIDANCE/PREDICTABILITY ASSESSMENT
AN AMPLIFIED MEAN UPPER TROUGH WITH A SERIES OF EMBEDDED
SHORTWAVES WILL SETTLE OVER MUCH OF THE LOWER 48 BY EARLY NEXT
WEEK IN A COLD WINTER PATTERN. AMPLIFIED UPPER RIDGING SLOWLY WORKING
FROM THE EASTERN PACIFIC TO THE NORTHWEST/WEST WILL COINCIDE WITH
DOWNSTREAM SHORTWAVE DIGGING THROUGH A COOLING WEST, LIKELY LEADING
TO THE SPLITTING AND UNDERCUTTING OF DEVELOPING CLOSED LOW ENERGY
BACK OVER THE SOUTHWEST TO OFFSHORE CALIFORNIA. MEANWHILE, HIGH
PRESSURE BUILDING IN THE WEST EARLY NEXT WEEK AND INCREASED
PRESSURE GRADIENTS MAY SUGGEST STRONGER THAN GUIDANCE WINDS/GUSTS.
FORECAST SPREAD AND UNCERTAINTY SEEM BELOW NORMAL IN GUIDANCE
SUNDAY INTO TUESDAY IN A LESS ACTIVE WEATHER PATTERN FOR MUCH OF
THE LOWER 48. PREDICTABILITY SEEMS TO LOWER TOWARD AVERAGE LEVELS
INTO MID-LATER NEXT WEEK, ESPECIALLY OVER THE MORE TRANSITIONAL
FLOW OVER THE WEST AND EASTERN PACIFIC. THE WPC MEDIUM RANGE
PRODUCT SUITE WAS PRIMARILY DERIVED FROM A BLEND OF BEST CLUSTERED
GUIDANCE FROM THE 18 UTC GFS/GEFS MEAN, THE 12 UTC ECMWF AND THE 12
UTC ECMWF/CANADIAN ENSEMBLE MEANS ALONG WITH THE COMPATIBLE 01 UTC
NATIONAL BLEND OF MODELS. WPC BLEND EMPHASIS ON THE MODELS THROUGH
EARLY NEXT WEEK MOVES TO THE ENSEMBLE MEANS MID-LATER NEXT WEEK
AMID SLOWLY FROWING VARIANCES. THIS FORECAST PLAN MAINTAINS GOOD
WPC CONTINUITY AND SEEMS MAINLY IN LINE WITH LATEST 00 UTC MODELS.
..WEATHER/HAZARDS HIGHLIGHTS
AN ANOMALOUSLY COLD AIR MASS WILL REMAIN IN PLACE OVER THE SOUTH,
SOUTHEAST, AND MID-ATLANTIC THROUGH THE WEEKEND, AND TRAILING
FRONTS MAY CONTINUE TO FOCUS PERIODIC RAIN/CONVECTION BACK ACROSS
FLORIDA, THE GULF OF MEXICO, AND SOUTHERN TEXAS NEXT WEEK.
LOW PRESSURE SYSTEM TRANSLATION AND UPPER SUPPORT SHOULD FAVOR
LIGHT TO MODERATE ORGANIZED SNOWS EXPECTED TO SLOWLY WORK OVER THE
MIDWEST AND GREAT LAKES EARLY NEXT WEEK, THEN LEADING TO THE
TRIGGERING OF ADDITIONAL LAKE EFFECT SNOWS. IN THE WAKE OF THIS
SYSTEM, ANOTHER BLAST OF ARCTIC AIR IS FORECAST TO SPILL INTO THE
NORTH-CENTRAL U.S. AND SPREAD TO THE EAST AND SOUTHEAST NEXT
WEEK. HAZARDOUS COLD TEMPERATURES ARE EXPECTED FROM THE NORTHERN
PLAINS TO THE GULF AND SOUTHEAST COASTS, WITH TEMPERATURE ANOMALIES
POTENTIALLY REACHING 10-20 DEGREES BELOW NORMAL.
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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