416
FXUS02 KWBC 060641
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
240 AM EDT TUE JUN 06 2023
VALID 12Z FRI JUN 09 2023 - 12Z TUE JUN 13 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...
..OVERVIEW
A VERY AMPLIFIED AND BLOCKY FLOW PATTERN SHOULD PERSIST THROUGH AT
LEAST THIS COMING WEEKEND WITH AN ANOMALOUSLY STRONG UPPER
RIDGE/HIGH SANDWICHED BETWEEN MEAN TROUGHING/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, POSSIBLY CLOSING OFF A
LOW OVER/NEAR THE OHIO VALLEY LATE PERIOD. THIS WOULD ALLOW THE
PRECIP FOCUS TO SHIFT EAST FROM THE ROCKIES AND APPROACH THE
EASTERN SEABOARD BY EARLY NEXT WEEK.
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
A GENERAL MODEL BLEND OF THE LATEST DETERMINISTIC SOLUTIONS WORKED
WELL FOR DAYS 3-5 AMIDST GOOD MODEL AGREEMENT ON THE RATHER STATIC
PATTERN IN PLACE INTO THE WEEKEND. OUT WEST, MODELS SHOW GOOD
SYNOPTIC AGREEMENT ON THE NEXT UPPER LOW SETTLING OVER CALIFORNIA
AND TROUGHING MAINTAINED OVER THE WESTERN U.S.. THERE GREATEST
AREA OF UNCERTAINTY LATE IN THE PERIOD IS WITH THE WAVE DROPPING
TOWARDS THE GREAT LAKES THIS WEEKEND AND MODELS SEEM TO BE
TRENDING MORE AGGRESSIVE WITH THIS FEATURE WITH MANY SHOWING A
CLOSED LOW AROUND SUNDAY/MONDAY. THERE IS DISAGREEMENT ON
PLACEMENT OF THIS LOW AND STILL CONSIDERABLE RUN TO RUN
INCONSISTENCIES. THERE ARE SCENARIOS WHERE THE LOW GETS HELD UP
OVER THE GREAT LAKES, DROPS SOUTH INTO THE APPALACHIANS OR THE
SOUTHEAST, OR PROGRESSES QUICKLY INTO THE NORTHEAST. OBVIOUSLY,
THIS HAS IMPLICATIONS ON EVENTUAL PRECIPITATION INTO THE EASTERN
U.S. LATE PERIOD AND WILL NEED TO BE WATCHED. THE ENSEMBLE MEANS
ARE MORE SUBDUED BUT DO OFFER A NICE MIDDLE GROUND SOLUTION AT
THIS POINT. OVERALL, MODELS ARE SHOWING INCREASING POTENTIAL THAT
THIS STUBBORN AND BLOCKY PATTERN OVER THE CONUS MAY FINALLY BEGIN
TO BREAK DOWN AND SHIFT EAST BY NEXT WEEK.
..WEATHER/HAZARDS HIGHLIGHTS
THE DAILY DIURNAL RISK FOR HEAVY SHOWERS AND THUNDERSTORMS FROM
THE SOUTHERN PLAINS THROUGH THE NORTHERN ROCKIES AND WESTWARD INTO
THE GREAT BASIN PERSISTS INTO AT LEAST THE WEEKEND AS TROPICAL
PACIFIC MOISTURE IS FUNNELED NORTHWARD BETWEEN A STRONG CENTRAL
U.S. RIDGE AND AN UPPER LOW PARKED OVER CALIFORNIA. THE DAYS 4 AND
5 EXCESSIVE RAINFALL OUTLOOKS CONTINUE TO DEPICT A LARGE MARGINAL
RISK ACROSS THIS ENTIRE REGION WITH AN EMBEDDED SLIGHT RISK OVER
MONTANA AS ANOMALOUS MOISTURE FOCUSES ALONG A FRONTAL BOUNDARY
OVER AN AREA THAT HAS BEEN VERY WET LATELY. ADDITIONAL EMBEDDED
SLIGHT RISKS ARE ALSO POSSIBLE WITHIN THE LARGER MARGINAL RISK
AREA, ESPECIALLY IF HEAVY RAINFALL FALLS OVER ANTECEDENT WET AREAS.
ELSEWHERE, A FRONT MOVING SOUTHWARD THROUGH THE UPPER MIDWEST AND
OHIO VALLEY LATER THIS WEEK INTO THE WEEKEND SHOULD FOCUS SHOWERS
AND THUNDERSTORMS ALONG THE BOUNDARY. A MARGINAL RISK WAS EXPANDED
INTO THIS REGION BY DAY 5 AS MODELS INDICATE POTENTIAL FOR AT
LEAST LOCALLY HEAVY RAINFALL AND CONVECTION. SLIGHT RISKS ARE
POSSIBLE AS WE GET CLOSER IN TIME, BUT AT THIS POINT, ITS FAR TOO
UNCERTAIN TO PICK OUT WHERE THE BEST FOCUS MAY BE. A LEADING COLD
FRONT SETTLING OVER THE SOUTHEAST SHOULD BE A SECONDARY FOCUS FOR
SCATTERED CONVECTION, WITH POSSIBLY MORE WIDESPREAD/HEAVY SHOWERS
ACROSS SOUTHERN FLORIDA LATER THIS WEEK ALONG A WEAKENING FRONT.
WARMER THAN AVERAGE TEMPERATURES, GENERALLY +10-15F, FROM THE
NORTHERN TIER TO THE NORTHWEST SHOULD MODERATE SOME THIS WEEKEND,
BUT MAY CREEP UP AGAIN EARLY NEXT WEEK. EXPECT NEAR TO BELOW
NORMAL TEMPERATURES OVER THE NORTHEAST AND AT TIMES INTO THE
MID-ATLANTIC BENEATH UPPER TROUGHING, MAINLY EARLY IN THE PERIOD.
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 SECOND UPPER LOW REACHING SOUTHERN
CALIFORNIA NEXT WEEKEND WILL BRING A REINFORCING SHOT OF MUCH
COOLER TEMPERATURES AS WELL.
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
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