043
FXUS02 KWBC 280716
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
315 AM EDT SAT MAY 28 2022
VALID 12Z TUE MAY 31 2022 - 12Z SAT JUN 04 2022
...MULTIPLE ROUNDS OF HEAVY RAINFALL ARE EXPECTED ACROSS
CENTRAL/SOUTHERN PARTS OF THE PLAINS AND MISSISSIPPI VALLEY NEXT
WEEK...
..OVERVIEW
THE MEDIUM RANGE PERIOD BEGINS TUESDAY WITH AN AMPLIFIED PATTERN
CONSISTING OF TROUGHING OVER THE WEST AND AN UPPER LOW ACROSS THE
CENTRAL U.S. WHILE RIDGING PREVAILS ACROSS THE GULF COAST STATES
INTO THE EAST, WITH THE EXCEPTION OF THE NORTHEAST WHERE THE RIDGE
IS SUPPRESSED BY AN EASTERN CANADA UPPER LOW. THE UPPER PATTERN
SHOULD FLATTEN ACROSS THE LOWER 48 AS ENERGY CONSOLIDATES INTO A
FAIRLY DEEP UPPER LOW ACROSS CENTRAL CANADA, BUT TROUGHING
EXTENDING FROM THE LOW WILL SHIFT A COLD FRONT SOUTHEASTWARD AS
NEXT WEEK PROGRESSES, PROVIDING A FOCUS FOR RAIN ESPECIALLY OVER
THE CENTRAL/SOUTHERN PLAINS AND THE MIDDLE/LOWER MISSISSIPPI
VALLEY WHERE MULTIPLE ROUNDS OF CONVECTION ARE LIKELY.
..MODEL GUIDANCE EVALUATION/PREFERENCES
ON DAY 3/TUESDAY AS THE PERIOD BEGINS, THERE ARE ALREADY SOME
DIFFERENCES WITH THE DETAILS OF ENERGY WITHIN THE WESTERN TO
NORTH-CENTRAL U.S. TROUGH. THE 12Z AND NEWER 00Z ECMWF/UKMET AS
WELL AS THE 12Z EC ENSEMBLE MEAN AGREE WITH THE EXISTENCE AND
POSITION OF A CLOSED UPPER LOW NEAR THE NORTH DAKOTA/MINNESOTA
BORDER TUESDAY MORNING, AND CMC RUNS ARE SIMILAR THOUGH NOT QUITE
A CLOSED LOW (DEPENDING ON THE CONTOUR INTERVAL). HOWEVER GFS RUNS
SEEM TO BE THE OUTLIERS WITH MORE STRUNG OUT UPPER ENERGY IN THE
AREA IN THE 18Z AND 00Z RUNS, WHILE THE 12Z SHOWED A CLOSED LOW
BUT TO THE NORTHEAST OF CONSENSUS, AND THE SURFACE LOWS SHOWED THE
SAME FAST/NORTHEAST POSITION. SO FAVORED THE NON-NCEP CONSENSUS
EARLY IN THE PERIOD, BUT BY DAY 4/WEDNESDAY MODELS INCLUDING THE
GFS GENERALLY COME TO BETTER AGREEMENT WITH A CONSOLIDATED LOW IN
CENTRAL CANADA. THERE ARE STILL SOME QUESTIONS WITH ADDITIONAL
UPSTREAM ENERGY TUESDAY-WEDNESDAY AROUND THE GREAT BASIN TO
CENTRAL ROCKIES AS TO WHETHER THERE COULD BE AN ADDITIONAL SMALL
CLOSED LOW AND HOW LONG THE ENERGY WILL LAST BEFORE GETTING
ABSORBED INTO THE MEAN FLOW. A MULTI-MODEL BLEND SEEMED REASONABLE
THOUGH THERE IS VARIETY IN THE DETAILS.
ELSEWHERE, MODEL GUIDANCE IS AGREEABLE WITH INITIAL RIDGING FROM
THE SOUTH-CENTRAL TO EASTERN U.S. BEFORE AN UPPER HIGH/RIDGE
RETROGRADES TOWARD THE SOUTHERN PLAINS/NORTHERN MEXICO, CONNECTING
WITH THE RIDGE THAT BUILDS OVER THE INTERIOR WEST/ROCKIES.
MEANWHILE UPPER ENERGY LOOKS TO SLOWLY DRIFT WEST ACROSS THE
WESTERN ATLANTIC TOWARD FLORIDA WEDNESDAY-THURSDAY, BUT WITH
UNCERTAINTY IN ITS STRENGTH, AND THEN QUESTIONS AS TO WHETHER IT
COULD MERGE WITH TROUGHING ACROSS THE EAST. GFS RUNS SHOW THIS
TROUGH MERGE MORE THAN OTHER GUIDANCE, LIKELY BECAUSE IT ALSO
COMBINES WITH ENERGY STEMMING FROM WHAT IS CURRENTLY TROPICAL
DEPRESSION ONE-E IN THE EASTERN PACIFIC. THERE IS AMPLE
UNCERTAINTY WITH THE POTENTIAL FOR ANY REDEVELOPMENT OF THE
FEATURE AND ITS TRACK AND TIMING, BUT IF ANY ENERGY OR A FEATURE
DOES PERSIST OR REDEVELOP, A TRACK AS FAST AS THE GFS RUNS SEEMS
UNLIKELY AS OTHER GUIDANCE IS MUCH SLOWER. THEN TROUGHING IS
EXPECTED TO COME INTO THE NORTHWEST LATE WEEK STEMMING FROM AN
UPPER LOW IN THE EASTERN PACIFIC, WITH ABOUT AVERAGE CONFIDENCE
AND A TREND TOWARD A FARTHER SOUTH UPPER LOW IN THE NEWER 00Z
GUIDANCE.
THUS THE WPC MEDIUM RANGE FORECAST UTILIZED A MULTI-MODEL
DETERMINISTIC BLEND EARLY IN THE PERIOD FAVORING THE ECMWF, THEN
PHASING IN THE GEFS AND EC ENSEMBLE MEANS TO HALF BY THE END OF
THE PERIOD TO REDUCE THE INFLUENCE OF INDIVIDUAL MODEL RUNS.
..SENSIBLE WEATHER/THREAT HIGHLIGHTS
THE SURFACE LOW PRESSURE SYSTEM LIFTING INTO CENTRAL CANADA
BEGINNING TUESDAY WILL SEND A COLD FRONT ACROSS THE NORTH-CENTRAL
U.S. AND ACROSS THE NORTHEASTERN QUADRANT THROUGH THE LATTER PART
OF THE WORKWEEK. RAIN IS POSSIBLE FIRST ACROSS NORTH DAKOTA AND
THE UPPER MIDWEST TO GREAT LAKES ALONG THIS FRONT TUESDAY AND THEN
SHIFTING EASTWARD ACROSS THE OHIO VALLEY AND INTO THE
NORTHEAST/MID-ATLANTIC BY THURSDAY, AFTER SOME INITIAL SHOWERS IN
PARTS OF THE NORTHEAST TUESDAY-WEDNESDAY NEAR A BACKDOOR FRONT.
HOWEVER, THE BACK END OF THE MAIN FRONT IS FORECAST TO MOVE MORE
SLOWLY THROUGH CENTRAL AND SOUTHERN PARTS OF THE PLAINS AND
MISSISSIPPI VALLEY, AND WILL PROVIDE A FOCUS FOR RAIN AND
THUNDERSTORMS FOR MULTIPLE DAYS AROUND TUESDAY-THURSDAY. FLASH
FLOODING IS POSSIBLE ESPECIALLY WHERE STORMS REPEAT OVER THE SAME
AREA, WHICH AT THIS POINT APPEARS MOST LIKELY TO OCCUR AROUND
KANSAS, OKLAHOMA, AND MISSOURI, BUT WITH UNCERTAINTY IN THE
DETAILS BEYOND THAT.
ELSEWHERE, FLORIDA COULD SEE A SHOWERY PATTERN NEXT WEEK AS WEAK
UPPER-LEVEL ENERGY PASSES THROUGH, WITH DIURNALLY FAVORED
CONVECTION. THIS MAY INCREASE BY LATE NEXT WEEK AS THERE IS
POTENTIAL FOR MOISTURE AND ENERGY ASSOCIATED WITH WHAT IS
CURRENTLY TROPICAL DEPRESSION ONE-E IN THE EASTERN PACIFIC TO LIFT
INTO THE GULF OF MEXICO. THERE IS AMPLE UNCERTAINTY WITH THE
POTENTIAL FOR ANY REDEVELOPMENT OF THE FEATURE AND ITS TRACK AND
TIMING, BUT REGARDLESS IT COULD ENHANCE MOISTURE AND RAINFALL
POTENTIAL OVER FLORIDA. THE NORTHWEST CAN EXPECT INCREASING
PRECIPITATION (MOST LIKELY RAIN) CHANCES LATER IN THE WEEK AS A
FRONT PUSHES THROUGH THE REGION.
THE EASTERN U.S./MISSISSIPPI VALLEY UPPER RIDGE WILL PROMOTE ABOVE
AVERAGE TEMPERATURES BY 10-20F OVER THE MIDWEST/OHIO VALLEY AND
PARTS OF THE NORTHEAST/MID-ATLANTIC TUESDAY-WEDNESDAY, WITH SOME
DAILY RECORD HIGH MAXIMUM AND MINIMUM TEMPERATURES POSSIBLE. THE
BACKDOOR FRONT REACHING NEW ENGLAND AND POSSIBLY AS FAR SOUTH AS
THE NORTHERN MID-ATLANTIC WOULD BRING A COOLER TREND TO THESE
AREAS THOUGH. MEANWHILE UPPER TROUGHING WILL BRING VERY COOL
TEMPERATURES TO AREAS FROM THE INTERMOUNTAIN WEST THROUGH
NORTHERN/CENTRAL PLAINS THROUGH MIDWEEK WITH HIGHS FORECAST TO BE
10-20F OR BELOW NORMAL. THE FLATTENING PATTERN ALOFT WILL PUSH THE
INITIAL PLAINS COLD FRONT EASTWARD WHILE LEADING TO A MODERATING
TREND FOR BELOW NORMAL TEMPERATURES OVER THE CENTRAL U.S., WITH
MOSTLY SINGLE-DIGIT NEGATIVE ANOMALIES BY THURSDAY-FRIDAY, THOUGH
AROUND 10F BELOW NORMAL IN RAIN-COOLED KANSAS AND OKLAHOMA. THE
EAST SHOULD SEE SHRINKING COVERAGE OF WARM TEMPERATURES ON
THURSDAY AND ESPECIALLY FRIDAY-SATURDAY. THE WEST COAST AND INTO
THE GREAT BASIN COULD FLIP BACK TO WARMER THAN NORMAL TEMPERATURES
BY AROUND 5-15F WEDNESDAY AND BEYOND, FOLLOWED BY A MODEST COOLER
TREND ON FRIDAY-SATURDAY ALONG THE IMMEDIATE WEST COAST WITH THE
ARRIVAL OF A PACIFIC FRONT.
TATE
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, EXPERIMENTAL EXCESSIVE RAINFALL
OUTLOOK, WINTER WEATHER OUTLOOK PROBABILITIES AND HEAT INDICES ARE
AT:
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
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