424
FXUS02 KWBC 111756
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
156 PM EDT TUE MAR 11 2025
VALID 12Z FRI MAR 14 2025 - 12Z TUE MAR 18 2025
...HEAVY RAIN/FLOODING AND SEVERE WEATHER POSSIBLE FOR THE
MISSISSIPPI/OHIO/TENNESSEE VALLEYS AND SOUTHEAST LATE WEEK...
...WIDESPREAD HIGH WINDS CAUSE FIRE DANGER IN THE SOUTHERN PLAINS
AND LOCALIZED BLIZZARD CONDITIONS IN THE NORTH-CENTRAL CONUS...
..MULTIPLE ROUNDS OF PRECIPITATION LIKELY IN THE WEST
..OVERVIEW
THE FIRST WEATHER FEATURE OF CONCERN LATE THIS WEEK WILL BE AN
UPPER TROUGH WITH EMBEDDED UPPER LOW SUPPORTING A STRENGTHENING
SURFACE LOW IN THE CENTRAL HIGH PLAINS AS THE PERIOD BEGINS FRIDAY.
THIS LOW WILL TRACK NORTHEASTWARD INTO THE UPPER MIDWEST INTO
SATURDAY WITH POTENT COLD FRONTS TO ITS SOUTH. HAZARDS ASSOCIATED
WITH THE SURFACE LOW PRESSURE SYSTEM WILL INCLUDE HEAVY RAIN AND
SEVERE THUNDERSTORMS IN THE MISSISSIPPI VALLEY BEGINNING FRIDAY AND
INTO THE SOUTHEAST AND TENNESSEE/LOWER OHIO VALLEYS SATURDAY.
CONVECTION SHOULD REACH THE EASTERN SEABOARD SUNDAY. SNOW IS
POSSIBLE ON THE BACKSIDE OF THE LOW IN THE NORTHERN HALF OF THE
PLAINS INTO THE UPPER MIDWEST FRIDAY-SATURDAY. MEANWHILE AREAS OF
STRONG WINDS ARE LIKELY, WHICH COULD CAUSE FIRE DANGER ESPECIALLY
IN THE SOUTHERN PLAINS. WARMER THAN NORMAL TEMPERATURES WILL BE
COMMON AHEAD OF THE LOW AND ITS COLD FRONTS, WITH COOLER
TEMPERATURES BEHIND. BEHIND THAT LOW, ANOTHER UPPER TROUGH IS
FORECAST TO APPROACH THE WEST THIS WEEKEND AND SPREAD ADDITIONAL
PRECIPITATION THERE, LASTING INTO EARLY NEXT WEEK.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE LATEST MODEL GUIDANCE TODAY CONTINUES TO SHOW REASONABLE GOOD
AGREEMENT FOR THE LARGE SCALE UPPER PATTERN AND FEATURES FOR THE
MEDIUM RANGE PERIOD. THE UPPER TROUGH AND EMBEDDED UPPER LOW OVER
THE CENTRAL U.S. WILL ALLOW FOR A STRONG SURFACE LOW TO CONSOLIDATE
IN THE CENTRAL HIGH PLAINS. THE SURFACE LOW LOOKS TO BE AROUND
980MB EARLY FRIDAY AND IN THE 970S EARLY SATURDAY IN THE UPPER
MIDWEST, PER THE AVERAGE OF MODELS AND ENSEMBLE MEMBERS. ON SMALLER
SCALES, MODELS CONTINUE TO VARY A BIT MORE WITH FORECAST ASPECTS
LIKE THE POSITIONING OF BACKDOOR FRONTS IN THE EAST LATE THIS WEEK,
AND THE EXACT POSITIONING/TRACK OF THE LOW. DESPITE THESE DETAIL
DISCREPANCIES, A DETERMINISTIC MODEL BLEND SLIGHTLY FAVORING THE
ECMWF AND GFS CONTINUED TO WORK WELL FOR THE EARLY PART OF THE
FORECAST PERIOD.
BEYOND DAY 5, GREATER MODEL UNCERTAINTIES ARISE. FOR THE EAST, AS
THE UPPER TROUGH CLEARS THE COAST EARLY NEXT WEEK, THERE ARE SOME
TIMING DIFFERENCES. OUT WEST, THERE IS A LITTLE GREATER MODEL
SPREAD WITH THE NEXT UPPER TROUGH INTO THE REGION AROUND MONDAY.
LATEST GUIDANCE CONTINUES TO TREND TOWARDS A LITTLE STRONGER
SURFACE LOW OFF THE PACIFIC NORTHWEST ON SUNDAY. AS THE TROUGH
PROGRESSES INLAND MONDAY INTO TUESDAY, THERE ARE GROWING QUESTIONS
ON TIMING AND SMALLER SCALE EMBEDDED PIECES OF ENERGY. THE WPC
BLEND FOR THE LATER PERIOD (MONDAY AND TUESDAY NEXT WEEK), TRENDED
TO A 50/50 BLEND OF THE ENSEMBLE/DETERMINISTIC GUIDANCE. THIS
HELPED MAINTAIN GOOD CONTINUITY WITH THE PREVIOUS WPC FORECAST AS
WELL.
..WEATHER/HAZARDS HIGHLIGHTS
AS THE PRIMARY UPPER TROUGH MOVES INTO THE CENTRAL U.S., THERE IS
HIGH CONFIDENCE IN SURFACE LOW DEVELOPMENT/CONSOLIDATION IN THE
CENTRAL PLAINS BY FRIDAY WITH STRONG FRONTS AND NORTHEASTWARD
PROGRESSION OF THE SYSTEM THEREAFTER. POTENTIAL EXISTS FOR THIS LOW
TO CHALLENGE SOME SEA LEVEL PRESSURE RECORDS FOR MARCH FROM
EASTERN NEBRASKA INTO PARTS OF MINNESOTA/WISCONSIN. ON THE BACKSIDE
OF THE LOW, SNOW MAY BE POSSIBLE ACROSS THE CENTRAL HIGH PLAINS
AND INTO THE DAKOTAS ON FRIDAY AND FRIDAY NIGHT. THERE IS HIGHER
CONFIDENCE FOR MEANINGFUL SNOW ACROSS THE EASTERN DAKOTAS INTO
WESTERN MINNESOTA BY SATURDAY WRAPPING AROUND THE LOW. SOME OF
THESE AREAS MAY INITIALLY SEE RAIN IN THE WARM SECTOR, AND A
TRANSITION ZONE OF ICE IS ALSO POSSIBLE BEFORE CHANGING OVER TO
SNOW. WIDESPREAD HIGH WINDS IN THE CENTRAL U.S. ARE ANOTHER
POTENTIAL HAZARD WITH THE LOW. IN NORTHERN AREAS, LOCATIONS THAT
RECEIVE SNOW COULD EXPERIENCE BLIZZARD CONDITIONS FRIDAY-SATURDAY
GIVEN THE STRONG WINDS. MEANWHILE FARTHER SOUTH, HIGH WINDS IN THE
SOUTHERN ROCKIES AND SOUTHERN PLAINS WILL CAUSE FIRE WEATHER
CONCERNS.
RAIN AND THUNDERSTORM CHANCES WILL EMERGE AHEAD OF THE COLD FRONT
ACROSS THE MISSISSIPPI VALLEY ON FRIDAY. THE STORM PREDICTION
CENTER IS HIGHLIGHTING SEVERE POTENTIAL THERE. MOST GUIDANCE SHOWS
HEAVY RAIN RATE POTENTIAL BEGINNING LATE FRIDAY INTO FRIDAY NIGHT
THAT COULD CAUSE FLOODING CONCERNS. THE DAY 4/FRIDAY ERO MAINTAINS
A MARGINAL RISK FOR THE LOWER/MIDDLE MISSISSIPPI VALLEY AND MID-
SOUTH ON FRIDAY, WITH SOME EXPANSION OF THE AREA COMPARED TO THE
PREVIOUS ISSUANCE. BY SATURDAY, RAINFALL TOTALS LOOK MORE
SUBSTANTIAL AS THE LARGER SYSTEM SLOWS AND THE POTENTIAL FOR HIGH
RAIN RATES AND TRAINING STORMS INCREASES WITHIN AN UNSTABLE
ENVIRONMENT WITH GOOD DYNAMICS FOR LIFT. THE DAY 5/SATURDAY ERO
SHOWS A SLIGHT RISK OF FLASH FLOODING ACROSS MUCH OF ALABAMA AND
TENNESSEE AND NEARBY, WHILE A SURROUNDING MARGINAL RISK REACHES
FROM THE CENTRAL GULF COAST INTO THE OHIO VALLEY. SPC ALSO
INDICATES SEVERE POTENTIAL FOR SIMILAR AREAS SATURDAY. RAIN AND
STRONG TO SEVERE THUNDERSTORMS AREA LIKELY TO PUSH ACROSS THE EAST
ON SUNDAY AHEAD OF THE COLD FRONT CONTINUING EASTWARD.
ADDITIONAL ROUNDS OF PRECIPITATION ARE LIKELY IN THE WEST LATE
THIS WEEK INTO THE WEEKEND WITH MULTIPLE FRONTAL SYSTEMS CHANNELING
PACIFIC MOISTURE INLAND. RAIN AMOUNTS IN THE PACIFIC NORTHWEST TO
NORTHERN CALIFORNIA LOOK TO STAY BELOW THRESHOLDS FOR ANY EXCESSIVE
RAINFALL RISK THROUGH FRIDAY, BUT CHANCES FOR HEAVY PRECIPITATION
(LOWER ELEVATION RAIN AND HIGHER ELEVATION SNOW) COULD INCREASE BY
THE WEEKEND FOR THE PACIFIC NORTHWEST INTO CALIFORNIA. CURRENT
FORECASTS SHOW A WEAK TO MODERATE ATMOSPHERIC RIVER COMING INTO THE
PACIFIC NORTHWEST SATURDAY NIGHT AND MOVING SOUTHWARD INTO
CALIFORNIA ON SUNDAY. HELD OFF FROM DELINEATING ANY AREA IN THE DAY
5/SATURDAY ERO AS THE COASTAL PACIFIC NORTHWEST IS NOT VERY
SENSITIVE TO HEAVY RAIN, BUT SOME LOCALIZED RAIN RATES OF AN INCH
PER HOUR OR MORE ARE POSSIBLE, WHICH COULD MAKE THE FLOODING RISK
NONZERO. THE AR CURRENTLY LOOKS TO WEAKEN AS IT PUSHES INTO CENTRAL
AND SOUTHERN CALIFORNIA SUNDAY, HOPEFULLY PRECLUDING TOO MANY
FLOODING ISSUES OVER RECENT BURN SCARS. PRECIPITATION IS ALSO
LIKELY FARTHER EAST INTO THE INTERIOR WEST AND ROCKIES THROUGH THIS
WEEKEND AND EARLY NEXT WEEK WITH SOME HEAVY SNOW POTENTIAL IN THE
HIGHER TERRAIN.
ABOVE AVERAGE TEMPERATURES ARE LIKELY OVER THE EASTERN HALF OF THE
COUNTRY FRIDAY. TEMPERATURE ANOMALIES OF 20 TO AS MUCH AS 35
DEGREES ABOVE NORMAL ARE FORECAST FRIDAY FOR THE UPPER MIDWEST AS
HIGHS REACH THE 60S AND 70S. FARTHER SOUTH, TEMPERATURES IN TEXAS
INTO THE LOWER MISSISSIPPI VALLEY COULD REACH THE 80S WHILE
LOCALIZED AREAS LIKE FAR SOUTH TEXAS CAN EXPECT 90S, EVEN
APPROACHING 100F. WARMER THAN NORMAL TEMPERATURES WILL GRADUALLY
SHRINK IN AREA INTO THE WEEKEND AS POSSIBLY MULTIPLE COLD FRONTS
TRACK EAST. TEMPERATURES OF 20 TO 30 DEGREES ABOVE AVERAGE WILL BE
MORE LIMITED TO THE GREAT LAKES ON SATURDAY, AND WARMER THAN NORMAL
TEMPERATURES BY 15-25F ARE LIKELY IN THE NORTHEAST OVER THE
WEEKEND. THERE COULD BE A FEW DAILY RECORD HIGHS ISOLATED ACROSS
THE CENTRAL TO EASTERN U.S., BUT THERE COULD BE MORE WIDESPREAD
RECORD WARM LOWS FROM THE MIDWEST THROUGH THE EAST FRIDAY-SUNDAY IF
THE MORNING MINS HOLD FOR THE CALENDAR DAY. AFTER NEAR NORMAL
TEMPERATURES RETURN, TEMPERATURES MAY WARM TO ABOVE AVERAGE AGAIN
IN THE CENTRAL AND EASTERN U.S. EARLY NEXT WEEK WITH ANOTHER BOUT
OF UPPER RIDGING. MEANWHILE IN THE WEST, THE INITIAL UPPER
TROUGHING WILL PROMOTE BELOW NORMAL TEMPERATURES ACROSS THE REGION
FRIDAY INTO SATURDAY. HIGHS ARE FORECAST TO BE GENERALLY BELOW
AVERAGE BY 15-20 DEGREES FOR THE CENTRAL GREAT BASIN AND SOUTHWEST,
WHILE LOWS OF 5-15 DEGREES BELOW NORMAL ARE LIKELY. TEMPERATURES
SHOULD MODERATE SOMEWHAT BY SUNDAY AS THE TROUGH PULLS AWAY, BUT
ANOTHER TROUGH APPROACHING COULD LEAD TO ANOTHER ROUND OF COOL
TEMPERATURES THERE EARLY NEXT WEEK.
SANTORELLI/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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