283
FXUS02 KWBC 031820
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
220 PM EDT WED APR 3 2024
VALID 12Z SAT APR 06 2024 - 12Z WED APR 10 2024
...HEAVY RAIN AND FLASH FLOODING CONCERNS WILL INCREASE IN THE
SOUTHERN U.S. NEXT WEEK...
..PATTERN OVERVIEW
INITIALLY AN OMEGA STYLE BLOCKING PATTERN WILL BE IN PLACE OVER
THE CONTINENTAL U.S. LATE THIS WEEK, WITH A DEEP UPPER LOW OVER THE
NORTHEAST AND ANOTHER DEEP LOW OVER THE WEST, SANDWICHING A
CENTRAL NATION UPPER RIDGE. THIS PATTERN WILL BE SLOWLY PROGRESSIVE
OVER THE WEEKEND AS THE NORTHEASTERN UPPER LOW EXITS INTO THE
ATLANTIC AND THE WESTERN LOW LIFTS NORTHEASTWARDS TOWARDS THE UPPER
MIDWEST THROUGH MID-NEXT WEEK. AS THE LOW LIFTS, IT WILL BE
ACCOMPANIED BY A SURFACE FRONTAL SYSTEM THAT COULD BRING A CHANCE
OF SHOWERS TO PARTS OF THE CENTRAL U.S. AND THE OHIO, TENNESSEE,
AND LOWER MISSISSIPPI VALLEYS (THIS WILL LIKELY HAVE IMPLICATIONS
FOR ECLIPSE VIEWING ON MONDAY). ANOTHER UPPER LOW WILL DIG DOWN THE
WEST COAST INTO THE SOUTHWEST EARLY IN THE WEEK AND MOVE INTO THE
SOUTH- CENTRAL U.S. BY MID-NEXT WEEK. THIS PATTERN WILL LIKELY
PRODUCE EXCESSIVE RAINFALL THAT COULD LEAD TO FLASH FLOODING IN THE
SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY MID-NEXT WEEK.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODEL GUIDANCE REMAINS IN REASONABLY GOOD AGREEMENT ON THE WEATHER
PATTERN THROUGH THE MEDIUM RANGE PERIOD; HOWEVER, THERE IS STILL
AN EXPECTED AMOUNT OF SPREAD AND UNCERTAINTY FOR THIS TIME RANGE.
THE MAIN DIFFERENCES BETWEEN MODEL SOLUTIONS SURROUND THE COMPLEX
EVOLUTION OF THE FRONTAL SYSTEM MOVING ACROSS THE CENTRAL U.S. NEXT
WEEK. THERE ARE DIFFERENCES IN HOW THE MODELS ARE HANDLING THE
EJECTION OF THE UPPER LOW TOWARDS THE UPPER MIDWEST, WHICH WILL IN
TURN AFFECT TIMING AND LOCATION OF FRONTS, PRECIPITATION, AND CLOUD
COVER.
THE WPC FORECAST WAS MAINLY DERIVED FROM A MULTI-MODEL BLEND OF
THE 06 UTC GFS AND 00 UTC ECMWF/UKMET/CMC FOR MAXIMUM SYSTEM DETAIL
THROUGH THIS WEEKEND INTO MONDAY. FOR TUESDAY AND WEDNESDAY,
ENSEMBLE MEANS FROM THE GEFS AND EC ENSEMBLE WERE ADDED TO THE
BLEND IN INCREASING AMOUNTS TO SMOOTH OUT MODEL DIFFERENCES AND
MAINTAIN TRENDS WITH THE AMPLIFIED UPPER PATTERN.
..WEATHER/HAZARDS HIGHLIGHTS
THE STRONG LOW PRESSURE SYSTEM THAT WILL IMPACT THE NORTHEAST LATE
THIS WEEK WILL MOVE OFFSHORE BY THIS WEEKEND, BUT LIGHT TO LOCALLY
MODERATE PRECIPITATION MAY LINGER OVER NEW ENGLAND AND DOWNWIND OF
THE GREAT LAKES ON SATURDAY. BRISK NORTHWESTERLY FLOW ON THE
BACKSIDE OF THE SYSTEM WILL PERSIST ACROSS THE NORTHEAST ON
SATURDAY, THEN DECREASE ON SUNDAY AS THE PRESSURE GRADIENT WEAKENS.
MEANWHILE, UNSETTLED WEATHER WILL IMPACT THE PACIFIC NORTHWEST AND
NORTHERN AND CENTRAL ROCKIES AS A COLD FRONT DROPS SOUTH FROM
CANADA AND A LOW PRESSURE SYSTEM STRENGTHENS OVER THE PLAINS. HEAVY
SNOW WILL BE POSSIBLE FOR PARTS OF THE NORTHERN ROCKIES SATURDAY
INTO SUNDAY, THEN CONDITIONS WILL IMPROVE AS THE SYSTEM PROGRESSES
EAST. EARLY NEXT WEEK, THIS SYSTEM WILL BRING A LARGE SWATH OF
SHOWERS AND THUNDERSTORMS (WITH SOME SEVERE THUNDERSTORMS POSSIBLE)
ACROSS THE PLAINS AND MISSISSIPPI VALLEY INTO THE MIDWEST. THIS
SYSTEM WILL BE RELATIVELY SLOW MOVING, WHICH COULD RESULT IN
LOCALLY HEAVY RAINFALL IN SOME AREAS. BEHIND THE SYSTEM, HIGH WINDS
WILL SPREAD FROM THE ROCKIES INTO THE PLAINS, WHICH WILL COMBINE
WITH DROPPING HUMIDITY TO PRODUCE A CRITICAL WILDFIRE RISK OVER
EASTERN NEW MEXICO, THE WESTERN HALF OF TEXAS, AND THE OKLAHOMA
PANHANDLE THIS WEEKEND.
UPSTREAM, A RENEWAL OF MAINLY LIGHT TO MODERATE PRECIPITATION IS
POSSIBLE ALONG THE WEST COAST EARLY NEXT WEEK AS A NEW PACIFIC
UPPER TROUGH/CLOSED LOW DIGS DOWN TOWARDS THE SOUTHWEST. THE FOCUS
FOR PRECIPITATION WILL THEN SHIFT TO THE SOUTH-CENTRAL U.S. TUESDAY
INTO WEDNESDAY, AND MOIST GULF INFLOW MAY BE RE-ENERGIZED AS A LOW
PRESSURE SYSTEM SWEEPS ACROSS THE SOUTHERN TIER OF THE NATION.
HEAVY RAINFALL SEEMS LIKELY ACROSS THE SOUTHERN PLAINS, LOWER
MISSISSIPPI VALLEY, AND MID-SOUTH, WHICH MAY LEAD TO FLASH FLOODING
CONCERNS.
TEMPERATURES WILL BE BELOW AVERAGE THIS WEEKEND INTO EARLY NEXT
WEEK ACROSS THE WESTERN U.S. AS UPPER LEVEL TROUGHING DOMINATES THE
WEATHER IN THIS REGION. TEMPERATURES FOR MUCH OF THE WEST SHOULD
REBOUND TO NEAR OR SLIGHTLY ABOVE AVERAGE BY TUESDAY, EXCEPT FOR IN
THE SOUTHWEST WHERE TEMPERATURES WILL REMAIN COOLER THAN AVERAGE.
IN THE CENTRAL U.S., TEMPERATURES SHOULD REMAIN NEAR TO SLIGHTLY
ABOVE AVERAGE WITH AREAS OF BELOW AVERAGE TEMPERATURES UNDER CLOUD
COVER AND PRECIPITATION. IN THE EAST, COLDER AIR WILL MOVE INTO THE
REGION BEHIND THE DEPARTING COASTAL LOW, WHICH WILL RESULT IN BELOW
NORMAL TEMPERATURES THIS WEEKEND. MORNING LOWS ARE FORECAST TO BE
NEAR FREEZING FROM THE NORTHEAST AND GREAT LAKES INTO THE MID-
MISSISSIPPI, OHIO, AND TENNESSEE VALLEYS, WHICH COULD AFFECT
SENSITIVE VEGETATION. A WARMING TREND SHOULD TAKE ROOT IN THE EAST
AND MIDWEST EARLY NEXT WEEK.
DOLAN/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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