007
FXUS02 KWBC 200600
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 AM EDT MON APR 20 2026
VALID 12Z THU APR 23 2026 - 12Z MON APR 27 2026
..OVERVIEW
A FAIRLY ACTIVE AND EVOLVING SPRING PATTERN ACROSS MUCH OF CONUS
AS A PACIFIC MID/UPPER-LEVEL TROUGH CONTINUES TO MOVE EAST ACROSS
THE ROCKIES/PLAINS BEFORE EJECTING EASTWARD INTO THE MIDWEST BY
LATE WEEK. THIS SYSTEM WILL BRING VERY STRONG WINDS AND WIDESPREAD
PRECIPITATION, INCLUDING LOW ELEVATION RAIN AND HEAVY MOUNTAIN
SNOW. AS THE TROUGH AND ITS ASSOCIATED SURFACE LOW INTERACTS WITH
SURGING GULF MOISTURE OVER THE CENTRAL U.S., EPISODES OF HEAVY RAIN
AND SEVERE WEATHER WILL BECOME MORE LIKELY THURSDAY AND FRIDAY.
THE SYSTEM WILL BRING PERIODS OF ANOMALOUS WARMTH AND LATE-SEASON
COOL INTRUSIONS AS BELOW AVERAGE TEMPERATURES EXPAND FROM THE
WESTERN U.S. TO THE CENTRAL U.S. BEHIND A STRONG EASTWARD ADVANCING
COLD FRONT.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODEL GUIDANCE REMAINS IN GENERALLY GOOD AGREEMENT ON THE LARGE-
SCALE EVOLUTION OF THE THE RIDGE OVER CENTRAL U.S. MOVING EASTWARD,
WHILE THE PACIFIC SYSTEM AND AMPLIFIED TROUGH LIFTS INTO
WESTERN/CENTRAL U.S. LATER IN THE PERIOD, MODEL SPREAD PERSIST
MOSTLY WITH THE UPPER LOW/TROUGH IN RESPECT TO THE TIMING AND
AMPLITUDE OF THE EMBEDDED SHORTWAVES AND ASSOCIATED SURFACE
FEATURES. THIS INCLUDES DIFFERENCES IN PLACEMENT OF FRONTAL ZONES
AND THE TRACK OF DEVELOPING SYSTEMS EMERGING FROM THE WEST. THE
ENSEMBLE MEANS CONTINUE TO SMOOTH SOME OF THE SMALL SCALE
DIFFERENCES AMONGST THE DETERMINISTIC MODELS. THE GFS CONTINUES TO
SHOW HIGHER RUN-TO-RUN VARIABILITY AND SOME NOTICEABLE DIFFERENCES
IN RESPECT TO SHORTWAVE TROUGHS. THE FORECAST INCORPORATED A BLEND
OF MODELS FOR THE INITIAL PERIOD, BUT GRADUALLY PHASED IN THE
ENSEMBLES BY DAY 5.
..WEATHER/HAZARDS HIGHLIGHTS
THE RIDGE OVER EASTERN U.S. WILL BREAK DOWN AND SHIFT OFFSHORE, AS
THE PACIFIC SYSTEM AND AMPLIFIED TROUGH CONTINUES TO DIGS ACROSS
WESTERN U.S. INTO CENTRAL U.S. THIS WILL BRING UNSETTLED
CONDITIONS ACROSS THE ROCKIES, PLAINS, AND MIDWEST. MULTIPLE
EMBEDDED SHORTWAVES ROTATING WITHIN AND AROUND THE BASE OF THE
TROUGH WILL BRING PERIODS OF WIDESPREAD LOW ELEVATION RAIN AND
MOUNTAIN SNOW, WITH LOCALLY HEAVY PRECIPITATION POSSIBLE ALONG
FAVORED TERRAIN. ACCUMULATING SNOW WILL PRIMARY BE CONFINED TO
HIGHER ELEVATIONS, WITH IMPACTS LIMITED TO HIGH MOUNTAIN PASSES AND
MOUNTAIN TOWNS. IN ADDITION, STRONG GUSTY WINDS ARE EXPECTED ACROSS
MUCH OF CENTRAL U.S. AS THE SYSTEM MOVES ACROSS INTO THE PLAINS AND
MISSISSIPPI VALLEY THROUGH THE WEEK.
THE DEEPENING PACIFIC SYSTEM EJECTS EASTWARD INTO THE PLAINS BY
THURSDAY, SUPPORTING THE EASTWARD PROGRESSION OF A COLD FRONT. THE
COLD FRONT WILL INTERACT WITH WARM GULF MOISTURE AND UNSTABLE
AIRMASS, WHICH WILL SUPPORT A CORRIDOR OF SHOWERS AND THUNDERSTORMS
ACROSS THE PLAINS INTO MUCH OF EASTERN U.S. THROUGH THE WEEKEND.
THE COMBINATION OF THE LARGE SCALE FORCING AND INCREASING
INSTABILITY ALONG AND AHEAD OF A STRENGTHENING SURFACE LOW AND
STRONG COLD FRONT, WILL SUPPORT WIDESPREAD CLUSTERS OF STRONG TO
SEVERE THUNDERSTORMS CAPABLE OF PRODUCING HEAVY RAINFALL AND
ISOLATED FLASH FLOODING OVER THE CENTRAL/SOUTH PLAINS AND PARTS OF
THE MISSISSIPPI VALLEY. THIS FLOODING THREAT IS HIGHLIGHTED BY A
MARGINAL RISK IN THE DAY 4/THURSDAY ERO. GIVEN INCREASING SOIL
MOISTURE FROM PREVIOUS BOUTS OF CONVECTION, AN UPGRADE TO A SLIGHT
RISK IS NOT OUT OF THE QUESTION IN FUTURE UPDATES. AS THE FRONT MOVES
FURTHER EAST, FLOOD RISK SHIFTS INTO THE OHIO/TENNESSEE VALLEY ON
FRIDAY. THIS FLOODING THREAT IS HIGHLIGHTED BY A MARGINAL RISK IN
THE DAY 5/FRIDAY ERO.
ELSEWHERE, A RELATIVELY WEAK COLD FRONT WILL CONTINUE TO PUSH
THROUGH THE OHIO VALLEY, MID-ATLANTIC, AND NORTHEAST ON THURSDAY,
BRINGING CHANCES FOR ISOLATED TO SCATTERED SHOWERS. OTHERWISE, MUCH
OF THE DESERT SOUTHWEST AND SOUTHEAST WILL BE MAINLY DRY THROUGH
THE END OF THE WEEK, BEFORE THE COLD FRONT DROPS INTO THE SOUTHERN
PLAINS/MISSISSIPPI VALLEY BY FRIDAY AND OVER THE SOUTHWEST BY THE
WEEKEND, WHICH MAY BRING SHOWERS AND THUNDERSTORMS FRIDAY INTO
THE WEEKEND.
BELOW NORMAL TEMPERATURES OVER MUCH OF WESTERN U.S. WILL EXPAND
EAST INTO NORTHERN/CENTRAL PLAINS AND ROCKIES BY THE END OF THE
WEEK AND PARTS OF MISSISSIPPI VALLEY BY THE WEEKEND. PARTS OF THE
NORTHERN PLAINS/ROCKIES WILL DROP TO 15-20 DEGREES BELOW NORMAL,
WHERE HIGHS WILL BE WITHIN THE 40S OVER THE NORTHERN ROCKIES ON
THURSDAY AND WILL GRADUALLY SPREAD INTO THE NORTHERN PLAINS BY
FRIDAY. AHEAD OF THE FRONTAL SYSTEM, ABOVE AVERAGE TEMPERATURES
WILL PERSIST THROUGH FRIDAY ACROSS PARTS OF CENTRAL U.S. INTO MUCH
OF EASTERN U.S. BEFORE TEMPERATURES MODERATE INTO THE WEEKEND. OVER
INTO THE PACIFIC NORTHWEST, TEMPERATURES WILL BEGIN TO TREND
SLIGHTLY ABOVE AVERAGE LATE IN THE PERIOD.
OUDIT
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, EXCESSIVE RAINFALL OUTLOOK, WINTER WEATHER OUTLOOK PROBABILITIES, HEAT INDICES AND KEY MESSAGES 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
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=OVW
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