166
FXUS02 KWBC 300649
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
249 AM EDT FRI MAY 30 2025
VALID 12Z MON JUN 02 2025 - 12Z FRI JUN 06 2025
..PATTERN OVERVIEW AND GUIDANCE/PREDICTABILITY ASSESSMENT
THROUGH THE DURATION OF THE EXTENDED PERIOD THERE WILL BE AN
AMPLIFIED SPLIT FLOW PATTERN ACROSS THE CONUS WITH BELOW AVERAGE
PREDICTABILITY. IN GENERAL MODEL CONSENSUS DEPICTS TROUGHS IN THE
WEST AND EAST WITH POTENTIAL TO CLOSE OFF AS THE WEEK PROGRESSES.
THERE HAS BEEN PERSIST RUN-TO-RUN DIFFERENCES THAT IMPACT THE
LOCATION, STRENGTH AND TIMING OF FRONTS, WEATHER CONDITIONS AND
PRECIPITATION TOTALS.
THE PREFERRED MODEL BLEND FOR THIS CYCLE COMPRISED OF THE 00Z
ECMWF/CMC/UKMET AND THE EC AND GEFS ENSEMBLE MEANS. THE WEIGHTING
OF MEANS INCREASED TO 50% FOR THE LATTER HALF OF THE FORECAST
PERIOD. AS PREVIOUSLY NOTED, THE GFS CONTINUED TO HANG ON TO THE
NOTION OF LAGGING BEHIND AND BEING STRONGER SHORTWAVE/VORT MAX
DESCENDING DOWN THE EASTERN FLANK OF A WESTERN U.S. RIDGE AT THE
START OF THE PERIOD.
..WEATHER/HAZARDS HIGHLIGHTS
AS AN AMPLIFIED UPPER TROUGH TRACKS SLOWLY OFF THE EAST COAST A
SERIES OF SHORTWAVES WILL DIG THROUGH THE FLOW; WHICH MAY
POTENTIALLY DEVELOP INTO A SEPARATED CLOSED LOW. A WAVY TRAILING
FRONT WILL SETTLE NEARBY FROM THE WESTERN ATLANTIC SOUTHWESTWARD TO
THE GULF. WHILE UNCERTAIN LOWS COULD ACT TO BRING SOME ACTIVITY
FROM THE COASTAL AREAS UP THE EASTERN SEABOARD SUNDAY AND INTO NEXT
WEEK, PARTICULAR RUNOFF ISSUES MAY DEVELOP WITH TIME FOR SOUTH
FLORIDA URBAN AREAS GIVEN DEEPER LOWER LATITUDE MOISTURE
AVAILABILITY AND SUPPORT TO MONITOR.
WHILE DIFFERENCES ON THE DETAILS PERSIST WITH TIME, THE GENERAL
CONSENSUS FAVORS UPPER TROUGH AMPLIFICATION WITH MULTIPLE SYSTEMS
INTO THE WEST ALONG WITH LEAD EJECTION OF A SOUTHERN STREAM CLOSED
SYSTEM FROM OFFSHORE BAJA THROUGH THE SOUTHWEST INTO THE ROCKIES.
THIS PATTERN CHANGE WILL BE A WELCOMED RELIEF TO RECENT HEAT ACROSS
THE WEST AS WELL AS TRANSITIONING TO A MORE UNSETTLED AND
INCREASINGLY WET FLOW PATTERN FARTHER INLAND AND DOWNSTREAM OVER
THE INTERMOUNTAIN WEST AND ESPECIALLY THE NORTHERN ROCKIES THROUGH
MIDWEEK. THIS WILL SUPPORT THE POSSIBILITY FOR ENHANCED MOUNTAIN
SNOW IN THE HIGHEST ELEVATIONS OF THE NORTHERN ROCKIES. FAVORABLE
UPPER SUPPORT, FRONTAL TRANSLATION, AND ANOMALOUS MOISTURE ALONG
WITH DOWNSTREAM CYCLE-/FRONTOGENESIS OVER THE PLAINS SHOULD ALSO
ACT TO ENHANCE PRECIPITATION AND AN EMERGING CONVECTIVE PATTERN
FROM PORTIONS OF THE NORTHERN ROCKIES TO THE NORTHERN PLAINS BY
THE START OF THE NEW WEEK. MAINTAINED THE BROAD MARGINAL RISK FOR
THE DAY 4 ERO FROM PORTIONS OF MINNESOTA, THE DAKOTAS, EASTERN
WYOMING AND NORTHEAST COLORADO. A BROAD MARGINAL RISK WAS
INTRODUCED FOR THE DAY 5 PERIOD AS THE PRECIPITATION ADVANCES OVER
THE CENTRAL PART OF THE COUNTRY AND ENCOMPASSES THE EASTERN
DAKOTAS, MINNESOTA, WESTERN WISCONSIN, IOWA, EASTERN NEBRASKA,
KANSAS, WESTERN MISSOURI AND NORTHEAST OKLAHOMA.
CAMPBELL/MILLER/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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