455
FXUS02 KWBC 171957
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
357 PM EDT FRI APR 17 2026
VALID 12Z MON APR 20 2026 - 12Z FRI APR 24 2026
..OVERVIEW
AN ACTIVE WEATHER PATTERN IS EXPECTED NEXT WEEK WITH A DEEP UPPER
LOW/TROUGH MOVING INTO THE WEST AND SHORTWAVE ENERGY EJECTING
ACROSS THE INTERMOUNTAIN WEST AND INTO THE PLAINS. THIS PATTERN
WILL PUSH A STRONG FRONTAL SYSTEM ACROSS THE WEST THAT WILL
STRENGTHEN OVER THE CENTRAL U.S. MID-TO-LATE NEXT WEEK AND BRING
WIDESPREAD PRECIPITATION CHANCES WITH THE POTENTIAL FOR MOUNTAIN
SNOW. COOLER THAN AVERAGE TEMPERATURES WILL PERSIST THROUGH EARLY
NEXT WEEK IN THE NORTHEAST WHILE ABOVE NORMAL TEMPERATURES DEVELOP
ACROSS THE INTERMOUNTAIN WEST AND THE PLAINS. ABOVE NORMAL TEMPS
SHOULD PUSH INTO THE EAST MID-WEEK.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODELS REMAIN IN GOOD AGREEMENT ON THE LARGE SCALE PATTERN THROUGH
EARLY NEXT WEEK, WITH INCREASING UNCERTAINTY MID-TO-LATE NEXT WEEK.
THE HIGHEST UNCERTAINTY SURROUNDS SHORTWAVE INTERACTIONS IN THE
WEST, WHICH WILL AFFECT TIMING OF SURFACE FEATURES AND SENSIBLE
WEATHER. SINCE THE PREVIOUS FORECAST, MODELS HAVE BEEN TRENDING A
BIT SLOWER WHEN PUSHING THE INITIAL SYSTEM ONSHORE IN THE WEST,
RESULTING IN A LONGER PERIOD OF PRECIPITATION AND HIGHER
PRECIPITATION TOTALS FOR CALIFORNIA. A BLEND OF THE AVAILABLE
DETERMINISTIC MODELS SERVED AS A GOOD STARTING POINT FOR THE
FORECAST, AND ENSEMBLE MEANS WERE ADDED IN INCREASING AMOUNTS
WEDNESDAY THROUGH FRIDAY TO HELP SMOOTH OUT MODEL DIFFERENCES.
..WEATHER/HAZARDS HIGHLIGHTS
INCREASING RETURN FLOW FROM THE GULF WILL SUPPORT A BROAD AXIS OF
MOISTURE CONVERGENCE AND INSTABILITY ALONG A FRONTAL BOUNDARY OVER
THE GULF, WHICH WILL TRIGGER CONVECTION OVER PORTIONS OF CENTRAL,
SOUTH, AND EAST TEXAS ON MONDAY AND TUESDAY. LOCALLY HEAVY RAINFALL
AND ISOLATED FLASH FLOODING MAY BE POSSIBLE, AND THERE IS A
MARGINAL RISK OF EXCESSIVE RAINFALL FOR THESE AREAS IN THE DAY
4/MONDAY AND DAY 5/TUESDAY EXCESSIVE RAINFALL OUTLOOKS (EROS).
MEANWHILE, A PACIFIC FRONTAL SYSTEM WILL GRADUALLY PUSH ONSHORE,
RESULTING IN INCREASING PRECIPITATION CHANCES ALONG THE WEST COAST
MONDAY INTO TUESDAY. MODERATE RAINFALL AND MOUNTAIN SNOW ARE
EXPECTED, WITH LOCALLY HEAVY RAINFALL POSSIBLE IN NORTHERN
CALIFORNIA THAT COULD LEAD TO ISOLATED FLOODING CONCERNS. THIS
FLOOD THREAT IS REPRESENTED BY A MARGINAL RISK OF EXCESSIVE
RAINFALL FOR PORTIONS OF NORTHERN CALIFORNIA IN THE DAY 4/MONDAY
AND DAY 5/TUESDAY EROS.
THE PACIFIC SYSTEM WILL PUSH ACROSS THE INTERMOUNTAIN WEST ON
WEDNESDAY AND EMERGE IN THE PLAINS WHILE STRENGTHENING WEDNESDAY
NIGHT INTO THURSDAY. WIDESPREAD PRECIPITATION CHANCES AND STRONG
GUSTY WINDS WILL ACCOMPANY THIS SYSTEM, SPREADING FROM THE
INTERMOUNTAIN WEST TO THE PLAINS AND MISSISSIPPI VALLEY.
ACCUMULATING SNOW WILL BE POSSIBLE ACROSS PORTIONS OF THE CENTRAL
AND NORTHERN ROCKIES AND INTO THE NORTHERN PLAINS. WHILE IMPACTS
SHOULD BE MAINLY CONFINED TO HIGHER ELEVATIONS, SOME TRAVEL IMPACTS
MAY BE POSSIBLE.
THE DESERT SOUTHWEST AND SOUTHEAST WILL EXPERIENCE MAINLY DRY
CONDITIONS NEXT WEEK, BUT ISOLATED SHOWERS AND STORMS WILL BE
POSSIBLE FOR SOUTH FLORIDA NEAR A STALLED FRONTAL BOUNDARY.
ISOLATED TO SCATTERED PRECIPITATION CHANCES WILL ALSO BE POSSIBLE
ALONG A RELATIVELY WEAK COLD FRONT FROM THE OHIO VALLEY TO NEW
ENGLAND EARLY NEXT WEEK.
TEMPERATURES WILL TREND BELOW AVERAGE EARLY NEXT WEEK OVER MUCH OF
THE EASTERN U.S. IN THE WAKE OF A COLD FRONT, AND FROST/FREEZE
CONDITIONS WILL BE POSSIBLE MONDAY NIGHT FOR THE OHIO VALLEY AND
CENTRAL/SOUTHERN APPALACHIANS. TEXAS WILL ALSO SEE BELOW AVERAGE
TEMPERATURES AS A RESULT OF FORECAST PRECIPITATION AND CLOUD COVER.
ABOVE NORMAL TEMPERATURES WILL DEVELOP OVER MUCH OF CENTRAL AND
WESTERN U.S. AHEAD OF THE STRONG FRONTAL SYSTEM, WITH THE ROCKIES
AND PLAINS SEEING HIGH TEMPERATURES RISE TO 15-25 DEGREES ABOVE
AVERAGE. MID-WEEK, WARMER TEMPERATURES WILL SPREAD TOWARDS THE EAST
COAST WHILE BELOW NORMAL TEMPERATURES SPREAD FROM WEST TO EAST
BEHIND THE WESTERN FRONTAL SYSTEM.
DOLAN/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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