564
FXUS02 KWBC 071901
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
300 PM EDT WED JUN 07 2023
VALID 12Z SAT JUN 10 2023 - 12Z WED JUN 14 2023
...A MULTI-DAY THUNDERSTORM AND LOCAL HEAVY RAIN THREAT WILL
CONTINUE INTO EARLY NEXT WEEK FROM A VERY SATURATED NORTHERN
ROCKIES THROUGH PORTIONS OF THE GREAT PLAINS...
...HEAVY RAIN/STRONG THUNDERSTORM THREAT FROM THE
MIDWEST/MID-SOUTH TO THE EAST THIS WEEKEND INTO EARLY NEXT WEEK
WITH CLOSED LOW GENESIS...
...TEXAS/VICINITY EXCESSIVE HEAT THREAT BY NEXT MIDWEEK MAY LINGER
AS PER THE CLIMATE PREDICTION CENTER...
..OVERVIEW
A QUITE BLOCKY FLOW PATTERN LOOKS TO PERSIST THROUGH AT LEAST
EARLY NEXT WEEK AS AN ANOMALOUSLY STRONG UPPER RIDGE/HIGH REMAINS
SANDWICHED BETWEEN MEAN TROUGHING/CLOSED LOWS OVER THE SOUTHWEST
AND THE NORTHEAST. THIS PATTERN CONTINUES TO SUPPORT DIURNAL
SHOWERS AND STORMS, SOME LOCALLY HEAVY, FROM THE SOUTHERN PLAINS
THROUGH THE NORTHERN ROCKIES AND PARTS OF THE GREAT BASIN. THE
NEXT WAVE ROUNDING THE MID-CONTINENTAL RIDGE CROSSES ONTARIO AND
APPROACHES THE NORTHEAST THIS WEEKEND, WITH GROWING CONSENSUS ON
CLOSING OFF A LOW OVER THE UPPER GREAT LAKES AROUND MONDAY-TUESDAY
NEXT WEEK. THIS WOULD PROMPT AN ADDITIONAL AND LOCALLY ENHANCED
PRECIPITATION FOCUS BY THE WEEKEND INTO EARLY NEXT WEEK OUT ACROSS
THE EAST-CENTRAL U.S. AND THEN THE EASTERN SEABOARD.
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
THERE REMAINS GOOD AGREEMENT ON THE WEATHER PATTERN ACROSS THE
CONUS THROUGH EARLY NEXT WEEK, AGAIN BOLSTERING FORECAST
CONFIDENCE. THE WPC PRODUCT SUITE VALID FOR THE FIRST HALF OF THE
PERIOD (SATURDAY INTO MONDAY) WAS BASED ON A COMPOSITE BLEND OF
THE LATEST DETERMINISTIC MODEL SOLUTIONS FROM THE
GFS/ECMWF/UKMET/CANADIAN AND THE NATIONAL BLEND OF MODELS. EVEN
INTO DAYS 6 AND 7 (TUESDAY AND WEDNESDAY) THOUGH, MODELS SEEM TO
BE SIMILARLY TRENDING TOWARDS A FAIRLY STRONG CLOSED LOW OVER THE
GREAT LAKES, WITH SOME WEAKENING/OPENING UP AS IT PUSHES INTO THE
NORTHEAST. PREFER A MODEL AND ENSEMBLE BLEND AT THESE LONGER TIME
FRAMES, BUT DID SLANT THE FORECAST IN THE DIRECTION OF RECENT
CANADIAN RUNS THAT OFFER A SLIGHTLY MORE AMPLIFIED AND LESS
PROGRESSIVE SOLUTION GIVEN NATURE OF THE BLOCKY FLOW AND ANY FAR
DOWNSTREAM AFFECTS FROM THE EXPECTED EMERGENCE OF TYPHOON GUCHUL
INTO THE PACIFIC WESTERLIES NEXT WEEK. IN THIS PATTERN OUT WEST,
THE MODELS AGREE IN THE IDEA THAT THE CLOSED LOW OVER
CALIFORNIA/THE SOUTHWEST SHOULD SLOWLY SPLIT/OPEN UP AND SHIFT
EAST AND POSSIBLY FINALLY BREAK DOWN THE BLOCKY PATTERN. PLENTY OF
UNCERTAINTY AND TRENDS LEFT TO MONITOR THOUGH. THIS MAINTAINS GOOD
CONTINUITY WITH THE PREVIOUS WPC PROGS AS WELL.
..WEATHER/HAZARDS HIGHLIGHTS
A DAILY RISK FOR HEAVY SHOWERS AND STRONG TO SEVERE THUNDERSTORMS
FROM THE SOUTHERN PLAINS THROUGH THE NORTHERN ROCKIES AND WESTWARD
INTO THE GREAT BASIN IS EXPECTED TO BE SLOW TO DISLODGE OVER ABOUT
THE NEXT WEEK AS TROPICAL PACIFIC MOISTURE REMAINS FUNNELED
NORTHWARD BETWEEN A STRONG CENTRAL U.S. RIDGE AND AN UPPER
LOW/TROUGH PARKED OVER CALIFORNIA/THE SOUTHWEST. A FRONTAL
BOUNDARY DROPPING SOUTH AND EASTWARD THROUGH THE REGION SHOULD
ALSO HELP TO ENHANCE RAINFALL TOTALS THIS WEEKEND, WITH PARTICULAR
CONCERNS OVER AREAS THAT HAVE BEEN VERY WET AS OF LATE (NORTHERN
AND CENTRAL ROCKIES/WESTERN GREAT PLAINS). THERE WAS ENOUGH MODEL
SUPPORT FOR A "SLIGHT RISK" ON THE DAY 4 EXCESSIVE RAINFALL
OUTLOOK FROM CENTRAL/EASTERN MONTANA INTO WESTERN NEBRASKA
ESPECIALLY GIVEN HIGH STREAM FLOWS IN THAT REGION. THE DYNAMICS
SUPPORT AT LEAST LOCALLY HEAVY CONVECTION AND POSSIBLE COMPLEXES
FARTHER SOUTH AND EAST ALONG THE BOUNDARY INTO THE SOUTH-CENTRAL
PLAINS/MISSISSIPPI VALLEY, BUT THERE IS STILL ENOUGH MODEL
UNCERTAINTY OVER THIS REGION WHICH HAS ALSO BEEN MUCH DRIER TO
PRECLUDE EXTENDING THE "SLIGHT RISK" THAT FAR EAST AS EARLY AS DAY
4, BUT DID SEEM REASONABLE TO BE ADDED FOR DAY 5 HEADING INTO THE
MID-SOUTH AND VICINITY GIVEN INCREASING SUPPORT. ALSO FOR DAY 5, A
SLIGHT RISK IS DEPICTED IN EASTERN COLORADO AND FAR SOUTHEAST
WYOMING MAINLY GIVEN THE ANTECEDENT WETNESS AND FAVORABLE
CONDITIONS. THE WPC HAZARDS OUTLOOK CHART ALSO SHOWS AN AREA
FAVORABLE FOR HEAVY RAINS INTO DAY 6 OVER THE GREAT LAKES AND THE
EAST GIVEN A JUNE UPPER LOW.
FARTHER INTO THE CENTRAL U.S. AND THE OHIO VALLEY, STRONG
THUNDERSTORMS SHOULD FOCUS ALONG THE FAIRLY PROGRESSIVE FRONTAL
BOUNDARY AND A MARGINAL RISK REMAINS EXPANDED INTO THIS REGION FOR
DAYS 4 AND 5 AS MODELS INDICATE THE POTENTIAL FOR AT LEAST LOCALLY
HEAVY RAINFALL. THE GREAT LAKES CLOSED UPPER TROUGH/LOW
DEVELOPMENT AND ASSOCIATED AND WRAPPING SURFACE LOW AND FRONTAL
CHARACTERISTICS TRAILING OVER THE APPALACHIANS/EAST/SOUTHEAST INTO
EARLY NEXT WEEK MAY THEN SET THE STAGE FOR DEVELOPMENT OF A
PATTERN FAVORING ADDITIONAL WIDESPREAD THREATS FOR HEAVY
RAIN/THUNDERSTORMS TO MONITOR. EJECTING ENERGIES OUT OF THE
SOUTHWEST ALSO LOOKS TO FAVOR ADDITIONAL ROUNDS OF RAINFALL AND
CONVECTION AGAIN AROUND MID-WEEK NEXT WEEK FOR PARTS OF THE
SOUTH-CENTRAL PLAINS.
TEMPERATURES OVER THE NORTHERN TIER AND BACK INTO THE PACIFIC
NORTHWEST SHOULD MODERATE SOME THIS WEEKEND, BUT MAY CREEP BACK UP
AGAIN EARLY NEXT WEEK WITH ANOMALIES GENERALLY +10-15F POSSIBLE.
UNDERNEATH POSSIBLE CLOSED LOW DEVELOPMENT OVER THE GREAT
LAKES/MIDWEST AND BACK INTO THE SOUTHWEST/CALIFORNIA, TEMPERATURES
SHOULD TREND COOLER THAN NORMAL. UPPER RIDGING MOVING INTO PARTS
OF THE SOUTHERN PLAINS EARLY TO MIDDLE OF NEXT WEEK SHOULD ALLOW
FOR WARMER THAN AVERAGE VALUES THERE AS WELL AND AN EMERGING
EXCESSIVE HEAT THREAT FOR TEXAS AND VICINITY MAY LINGER AS PER CPC.
SCHICHTEL/SANTORELLI
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
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page