072
FXUS02 KWBC 021931
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
330 PM EDT FRI JUN 02 2023
VALID 12Z MON JUN 05 2023 - 12Z FRI JUN 09 2023
...BROAD MULTI-DAY THUNDERSTORM AND LOCAL HEAVY RAIN THREAT FROM
THE NORTHERN ROCKIES TO THE SOUTHERN GREAT PLAINS CONTINUES WELL
INTO NEXT WEEK...
..OVERVIEW
THE UPPER LEVEL PATTERN DURING THE MEDIUM RANGE PERIOD NEXT WEEK
WILL REMAIN BLOCKY AS AN ANOMALOUSLY STRONG UPPER RIDGE REMAINS
PARKED OVER THE NORTHERN PLAINS/SOUTH-CENTRAL CANADA AND INTO THE
NORTHWEST U.S.. THIS SHOULD SUPPORT PROLONGED ABOVE NORMAL
TEMPERATURES FROM THE NORTHWEST INTO THE NORTHERN PLAINS AND THE
UPPER MIDWEST AND MISSISSIPPI VALLEY. MEANWHILE, A STATIONARY
UPPER LOW OVER/NEAR CALIFORNIA WILL MAINTAIN PERIODS OF CONVECTION
OVER MUCH OF THE CENTRAL/SOUTHERN PLAINS AND ROCKIES THROUGH NEXT
WEEK. IN THE NORTHEAST, AN UPPER LOW EXITING THE REGION ON DAY 3
WILL BE REPLACED BY ANOTHER UPPER LOW WHICH DRIVES LOWERING
HEIGHTS FARTHER SOUTH INTO THE MID-ATLANTIC SOMEWHAT COOLER AND
MORE UNSETTLED CONDITIONS.
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
THIS MORNING'S GUIDANCE CAPTURED THE OVERALL SYNOPTIC PATTERN
REASONABLY WELL DURING THE MEDIUM RANGE. A GENERAL MODEL BLEND
CONSISTING OF THE 00Z ECMWF/CMC/UKMET AND 06Z GFS WAS UTILIZED
THROUGH DAY 4, AND HIGHER WEIGHTING GIVEN TO THE EC DUE TO IT'S
RUN-TO-RUN CONSISTENCY IN ACROSS THE CONUS. THE 06Z GFS LOST SOME
FAVORABILITY ON DAY 3 BECAUSE OF ITS ATTEMPT TO BREAK DOWN THE
WEST COAST UPPER LOW EARLIER THAN THE REST OF THE MODELS. MODELS
BECOME MORE CONSISTENT AFTER DAY 4 DUE TO THE PREDICTABILITY OF
THE MASSIVE RIDGE OVER THE CENTRAL U.S.. THE 06Z GFS ATTEMPTS TO
CONSOLIDATE THE UPPER LEVEL ENERGY OVER THE NORTHEAST WHILE OTHERS
KEEP THEM SEPARATED AFTER DAY 4. THE ENSEMBLE MEANS ARE INTRODUCED
INTO THE BLEND ON DAY 6 AND ARE FAVORED THROUGH DAY 7 DUE TO THE
UNCERTAINTY OF THE NORTHEAST SYSTEM.
..WEATHER/HAZARDS HIGHLIGHTS
A CENTRAL CONTINENTAL RIDGE WITH WEAK TROUGHING OVER THE
INTERMOUNTAIN WEST KEEPS A MAINLY DIURNAL RISK FOR HEAVY SHOWERS
AND THUNDERSTORMS OVER MUCH OF THE ROCKIES/HIGH PLAINS THROUGH
TEXAS AND THE SIERRA NEVADA/GREAT BASIN NEXT WEEK. LOCALIZED FLASH
FLOOD POTENTIAL CONTINUES THROUGH AT LEAST TUESDAY GIVEN BROAD
MOIST FLOW FROM THE WESTERN GULF OF MEXICO ALONG WITH SOME
INSTABILITY. INCREASING TROPICAL PACIFIC MOISTURE FROM THE UPPER
LOW OVER CALIFORNIA EARLY NEXT WEEK BRINGS ADDITIONAL THREATS FOR
DIURNAL AND LOCALLY HEAVY SHOWERS AND STORMS FOR PARTS OF
CALIFORNIA AND THE GREAT BASIN. THE DAYS 4-5 EXCESSIVE RAINFALL
OUTLOOKS CONTINUE TO DEPICT JUST LARGE MARGINAL RISK AREAS FROM
CALIFORNIA/INTERMOUNTAIN WEST INTO THE ROCKIES AND SOUTHWARD TO
THE SOUTHERN PLAINS. EMBEDDED SLIGHT RISK AREAS MAY BECOME
NECESSARY, PARTICULARLY IF THE HEAVY RAIN FOCUS IS OVER ANTECEDENT
WET AREAS.
ELSEWHERE, A COLD FRONT THROUGH THE GREAT LAKES/UPPER MIDWEST
EARLY IN THE WEEK SHOULD FOCUS SHOWERS AND STORMS AHEAD OF IT
ACROSS THE NORTHERN PLAINS/UPPER MISSISSIPPI VALLEY. WITH DECENT
MOISTURE AND INSTABILITY, A MARGINAL RISK WAS ADDED TO THE DAYS 4
AND 5 EXCESSIVE RAINFALL OUTLOOKS. IN THE NORTHEAST, THE DEEPENING
UPPER TROUGH/LOWS SHOULD FAVOR POCKETS OF RAINFALL INTO FRIDAY.
THE LATEST ADVISORY FROM THE NHC FOR T.D. TWO HAS IT TRACKING
SOUTH AND DISSIPATING BEFORE NEXT WEEK, BUT A WEAKENING
FRONT/LINGERING TROUGHING OVER FLORIDA SHOULD ALLOW FOR CONTINUED
UNSETTLED WET CONDITIONS THROUGH MOST OF NEXT WEEK.
CENTRAL U.S. RIDGING ALOFT WILL MAINTAIN AN AXIS OF ABOVE NORMAL
TEMPERATURES FROM THE NORTHERN PLAINS SOUTH-SOUTHEAST TO THE
MID-SOUTH, WITH PLUS 10-15F ANOMALIES FOR HIGHS POSSIBLE MOST
DAYS. INITIAL WARMTH OVER THE GREAT LAKES WILL MODERATE EARLY NEXT
WEEK AFTER A COLD FRONT PUSHES THROUGH FROM THE NORTHEAST. THE
NORTHWEST WILL BE THE OTHER FOCUS FOR VERY WARM TEMPERATURES, WITH
HIGHS 10-20F OR SO ABOVE NORMAL. EXPECT BELOW NORMAL TEMPERATURES
OVER THE NORTHEAST AND AT TIMES INTO THE MID-ATLANTIC AS UPPER
TROUGHING BECOMES ESTABLISHED. CLOUDS AND PERIODS OF RAINFALL
SHOULD KEEP HIGHS 5-10F OR SO BELOW NORMAL OVER THE SOUTHERN HALF
OF THE ROCKIES/HIGH PLAINS FOR MOST OF THE PERIOD AND THE UPPER
LOW REACHING SOUTHERN CALIFORNIA MONDAY WILL ALSO BRING A COOLING
TREND INTO THE SOUTHWESTERN U.S. NEXT WEEK.
KEBEDE/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
HAZARDS:
- FLOODING POSSIBLE ACROSS PORTIONS OF THE NORTHERN PLAINS.
- FLOODING OCCURRING OR IMMINENT ACROSS PORTIONS OF THE NORTHERN
ROCKIES AND THE NORTHERN GREAT
BASIN.
- FLOODING LIKELY ACROSS PORTIONS OF THE CENTRAL ROCKIES, THE
CENTRAL GREAT BASIN, THE NORTHERN
ROCKIES, AND THE NORTHERN GREAT BASIN.
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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