937
FXUS02 KWBC 290748
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
348 AM EDT SUN MAR 29 2026
VALID 12Z WED APR 01 2026 - 12Z SUN APR 05 2026
...HEAVY RAIN AND FLOODING POTENTIAL ACROSS THE EAST-CENTRAL U.S.
FROM MIDWEEK INTO NEXT WEEKEND...
..OVERVIEW
A COUPLE OF SHORTWAVE TROUGHS WILL PUSH A WAVY FRONTAL SYSTEM
THROUGH THE CENTRAL AND EASTERN U.S. AND SPREAD PRECIPITATION
ACROSS THE REGION FOR MIDWEEK. MEANWHILE MORE AMPLIFIED TROUGHING
IS FORECAST TO MOVE INTO THE NORTHWEST BY THURSDAY AND EASTWARD
INTO LATE WEEK, CONTINUING UNSETTLED WEATHER THERE, INCLUDING
RAIN/MOUNTAIN SNOW AND STRONG WINDS. AS THAT TROUGH PUSHES EAST
INTO THE PLAINS, ADDITIONAL MOISTURE WILL BE DRAWN NORTH AND RENEW
POTENTIAL FOR HEAVY RAIN AND STORMS IN THE MISSISSIPPI VALLEY AND
VICINITY ONCE AGAIN, ENDING UP WITH MULTIPLE DAYS OF FLOODING
CONCERNS IN THAT REGION. WINTRY WEATHER INCLUDING SNOW AND ICE ARE
POSSIBLE ON THE NORTHERN SIDE IN PARTS OF THE NORTHEAST.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODEL GUIDANCE REMAINS AGREEABLE ON THE BROADER PATTERN, BUT WITH
DETAIL DIFFERENCES THAT HAVE IMPACTS ON SENSIBLE WEATHER. THE FIRST
CONCERNS ARE WITH THE DEPTH OF A LINGERING SHORTWAVE IN THE
NORTHEASTERN U.S. AT THE START OF THE PERIOD WEDNESDAY, WHILE A
SOUTHERN STREAM SHORTWAVE MOVES THROUGH THE FOUR CORNERS EASTWARD.
THESE FEATURES WILL HELP PLACE THE SURFACE FRONT AND THUS THE
ORIENTATION OF QPF WEDNESDAY AND THURSDAY. THE 12/18Z MODEL CYCLE
WAS SOMEWHAT SPLIT REGARDING THE FRONT/QPF AXIS, WITH THE EC AND
CMC SHOWING A MORE EASTWARD ORIENTATION WITH SOMEWHAT HEAVY QPF
FROM THE MS VALLEY INTO KENTUCKY/TENNESSEE WEDNESDAY FOR EXAMPLE,
WHILE THE GFS AND AI GUIDANCE HAD MORE OF A SOUTHWEST TO NORTHEAST
ORIENTATION ACROSS THE ARK-LA-TEX AND MS VALLEY INTO THE OHIO
VALLEY. THE NEWER 00Z RUNS OF THE EC/CMC HAVE TRENDED MORE TOWARD
THE LATTER CLUSTER, FOR BETTER MODEL AGREEMENT NOW. THIS IS A
NORTHWESTERN TREND COMPARED TO THE PREVIOUS FORECAST. THE
PRECIPITATION CONTINUES SLOWLY EAST INTO THURSDAY AS THE SHORTWAVE
AND FRONT MOVE.
MEANWHILE, THE UPSTREAM UPPER LOW SHOWS REASONABLY AGREEABLE
TIMING AS IT COMES INTO THE NORTHWEST BY EARLY THURSDAY. THEN THE
TIMING OF THAT LOW (POTENTIALLY OPENING INTO A TROUGH) MOVING EAST
LATE WEEK INTO THE WEEKEND SHOWS BETTER CONSENSUS THAN IT DID A DAY
AGO, AS THE 12Z ECMWF FINALLY BOUNCED EASTWARD MORE QUICKLY THAN
ITS PREVIOUS RUNS AND LOOKED MORE LIKE THE OTHER DYNAMICAL AND AI
MODELS, BUT THERE IS STILL SOME SPREAD. THE NEW 00Z CMC WAS SLOWER
THAN ITS PREVIOUS RUN AND APPEARS LESS LIKE THE MODEL CONSENSUS.
THERE ARE ALSO NOTABLE TIMING/PLACEMENT/STRENGTH DIFFERENCES WITH
THE ASSOCIATED SURFACE LOW THAT ARE YET TO BE RESOLVED.
THE WPC FORECAST USED A MULTI-MODEL BLEND AT THE START OF THE
FORECAST PERIOD. GIVEN THE BROAD SCALE AGREEMENT, WAS ABLE TO
MAINTAIN A MAJORITY OF DETERMINISTIC MODELS PLUS THE AIFS IN THE
MODEL BLEND FOR MASS FIELDS, WITH THE BLENDING PROCESS SERVING TO
MINIMIZE INDIVIDUAL SMALLER SCALE DIFFERENCES ALONG WITH SOME
INCLUSION OF THE ENSEMBLE MEANS.
..WEATHER/HAZARDS HIGHLIGHTS
A LOW PRESSURE/FRONTAL SYSTEM STRETCHING FROM THE NORTHEAST ACROSS
THE MID-SOUTH WILL TAP INTO GULF MOISTURE AND SPREAD RAIN AND
THUNDERSTORMS TO PORTIONS OF THE CENTRAL AND EASTERN U.S. MIDWEEK.
THE MOISTURE AND INSTABILITY ALONG WITH THE UPPER-LEVEL SUPPORT
COULD LEAD TO FLOODING CONCERNS ACROSS PARTS OF THE SOUTHERN PLAINS
TO LOWER/MIDDLE MISSISSIPPI VALLEY ON WEDNESDAY AS MULTIPLE ROUNDS
OF RAIN COULD OCCUR. A MARGINAL RISK REMAINS IN EFFECT FOR DAY
4/WEDNESDAY IN THOSE REGIONS, WITH A NORTHWESTERN SHIFT COMPARED TO
THE PREVIOUS ISSUANCES DUE TO MODEL TRENDS. RECENT MODEL GUIDANCE
MAY BE STARTING TO AGREE ON A CORRIDOR OF HIGHER RAIN TOTALS
GENERALLY FROM EASTERN OKLAHOMA INTO SOUTHWESTERN MISSOURI, AND A
SLIGHT RISK IS NOT OUT OF THE QUESTION IN FUTURE ISSUANCES, BUT
WILL CONTINUE TO MONITOR MODEL TRENDS FOR THE HEAVIEST AXIS AND IF
HIGH RAIN RATES AND TRAINING CAN OVERCOME THE DRY ANTECEDENT
CONDITIONS. ON THURSDAY, THE FRONTAL SYSTEM SHOULD GRADUALLY PUSH
EAST, AND WITH THE GENERALLY SIMILAR METEOROLOGICAL SETUP, WILL
ONCE AGAIN SHOW A BROAD MARGINAL RISK FROM THE LOWER/MIDDLE
MISSISSIPPI VALLEY INTO THE TENNESSEE AND OHIO VALLEYS INTO THE
GREAT LAKES REGION FOR THE DAY 5 ERO. PRECIPITATION IS LIKELY TO
CONTINUE ACROSS THE EAST INTO FRIDAY. CHILLIER AIR IN THE NORTHERN
TIER COULD ALLOW WINTRY WEATHER TO AFFECT THE GREAT LAKES TO
INTERIOR NORTHEAST. THIS COULD INCLUDE FREEZING RAIN/ICE ALONG WITH
A FEW INCHES OF APRIL SNOW.
TROUGHING MOVING THROUGH THE WEST WILL PROVIDE SUPPORT FOR
MODERATE PRECIPITATION WEDNESDAY-FRIDAY. SOME ENHANCED QPF IS
LIKELY ACROSS THE PACIFIC NORTHWEST TO NORTHERN CALIFORNIA ON
WEDNESDAY, BUT THE ATMOSPHERIC RIVER IS FORECAST TO REMAIN TOO WEAK
TO CAUSE FLOODING ISSUES. RAIN AND MOUNTAIN SNOW IS FORECAST TO
GRADUALLY OVERSPREAD THE INTERMOUNTAIN WEST. GUSTY WINDS COULD BE A
CONCERN ACROSS THE INTERMOUNTAIN WEST TO ROCKIES AND PLAINS WITH
THIS TROUGHY PATTERN. BY FRIDAY, A PRIMARY FOCUS OF HEAVIER RAIN
WILL RETURN BACK WEST INTO THE CENTRAL PLAINS/MIDDLE MISSISSIPPI
VALLEY FRIDAY IN RESPONSE TO THE UPPER TROUGH MAKING ITS WAY INTO
THE CENTRAL U.S. PULLING IN ADDITIONAL MOISTURE. BY SATURDAY THERE
MAY BE A SIMILAR HEAVY RAINFALL FOOTPRINT TO THE MIDWEEK RAIN
(ACROSS PARTS OF THE MS/TN/OH VALLEYS), POTENTIALLY EXACERBATING
FLOODING CONCERNS, SO WILL CONTINUE TO MONITOR. BREEZY CONDITIONS
COULD REACH THE MIDWEST BY THE WEEKEND DEPENDENT ON THE LOW TRACK.
WARMER THAN AVERAGE TEMPERATURES ARE FORECAST FOR THE SOUTHERN
TIER INTO THE EASTERN SEABOARD ON WEDNESDAY, WITH HIGHS IN THE 80S
REACHING INTO THE MID-ATLANTIC. THE EASTERN SIDE OF THE FRONT WILL
PUSH THROUGH PARTS OF THE EAST THURSDAY AND FRIDAY (ALBEIT WITH
UNCERTAINTY HOW FAR SOUTH IT SETS UP), BUT THE SOUTHEAST SHOULD
HANG ONTO WARMER TEMPERATURES UNDER THE INFLUENCE OF A BERMUDA
HIGH. ROUNDS OF COOLER THAN AVERAGE CONDITIONS ARE LIKELY TO MOVE
THROUGH THE NORTH-CENTRAL U.S. BEHIND COLD FRONTS. THE WEST CAN
GENERALLY EXPECT NEAR TO SLIGHTLY BELOW AVERAGE CONDITIONS THROUGH
THE LATTER PART OF THE WEEK, BUT WARMING TO ABOVE AVERAGE OVER THE
WEEKEND AS UPPER RIDGING POTENTIALLY COMES IN BEHIND THE TROUGH
ALOFT.
TATE
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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