483
FXUS02 KWBC 161957
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
357 PM EDT MON MAR 16 2026
VALID 12Z THU MAR 19 2026 - 12Z MON MAR 23 2026
...IMPRESSIVE EARLY SEASON HEAT WAVE CONTINUES ACROSS THE
SOUTHWESTERN U.S. THROUGH THE WEEKEND WITH NUMEROUS RECORDS,
GRADUALLY EASING EARLY NEXT WEEK...
..OVERVIEW
AN AMPLIFIED UPPER LEVEL FLOW PATTERN WILL BE IN PLACE THROUGH LATE
WEEK, SHIFTING TO MORE ZONAL EARLY NEXT WEEK. A HIGHLY ANOMALOUS
UPPER RIDGE WILL BE IN PLACE ACROSS THE SOUTHWEST AS THE PERIOD
BEGINS THURSDAY, BRINGING CONTINUED SUMMERLIKE HEAT THAT SHOULD SET
NUMEROUS DAILY AND SCATTERED MARCH TEMPERATURE RECORDS FOR
CALIFORNIA, THE INTERMOUNTAIN WEST, AND SPREADING INTO THE PLAINS.
THIS REGION SHOULD GRADUALLY MODERATE BUT STILL REMAIN WARM INTO
EARLY NEXT WEEK. JUST NORTH OF THE RIDGE, THE SOUTHERN END OF AN
ATMOSPHERIC RIVER COULD CAUSE HEAVY RAIN IN THE PACIFIC NORTHWEST
ESPECIALLY THROUGH THURSDAY. DOWNSTREAM, UPPER TROUGHING WILL BE IN
PLACE IN THE EAST, WITH RELOADING ENERGIES IN THE NORTHEAST AND
UNCERTAIN LOW PRESSURE POSSIBLY CAUSING RAIN AND SNOW.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODEL GUIDANCE REMAINS IN GOOD AGREEMENT FOR THE EARLY PART OF THE
FORECAST PERIOD, INCLUDING THE UPPER HIGH ATOP THE SOUTHWEST
REACHING OVER 594DM AT TIMES. DOWNSTREAM, THE TROUGH AXIS SHOULD
SLOWLY MOVE ACROSS THE EAST LATE WEEK. INTO NEXT WEEKEND, THE
INITIAL TROUGH SHOULD MOVE INTO THE ATLANTIC, BUT NORTHERN STREAM
ENERGY COULD AFFECT THE NORTHEASTERN QUADRANT OF THE U.S. ALONG
WITH POSSIBLE SURFACE LOW PRESSURE. THESE FEATURES ARE CONSIDERABLY
MORE UNCERTAIN, WITH A LOT OF RUN TO RUN INCONSISTENCY, SO EXPECT
FUTURE FORECAST CHANGES. THE 06Z AIFS WAS AMONG THE STRONGEST WITH
THE ENERGY AND SURFACE LOW BY SUNDAY, BUT THE 12Z AIFS DOES NOT DIG
THE ENERGY QUITE AS DEEP INTO THE EAST. DETERMINISTIC MODELS
GENERALLY VARY IN TIMING AND DEPTH WITHOUT A LOT OF CONSENSUS.
FARTHER WEST, CMC RUNS START TO BECOME A LITTLE OUT OF PHASE WITH
INDICATING TROUGHING IN THE INTERMOUNTAIN WEST BY EARLY NEXT WEEK
AND SUPPRESSING THE SOUTHWEST RIDGE MORE THAN OTHER GUIDANCE. THE
WPC FORECAST WAS BASED ON A MULTI-MODEL BLEND EARLY, BUT ENSEMBLE
MEANS REACHED HALF THE BLEND DAY 6 AND MORE DAY 7 GIVEN THE
INCREASING MODEL DIFFERENCES.
..WEATHER/HAZARDS HIGHLIGHTS
WARM TO HOT TEMPERATURES ARE FORECAST TO BREAK MARCH RECORDS
ACROSS MUCH OF THE SOUTHWESTERN U.S. MID TO LATE WEEK AS A MASSIVE
UPPER RIDGE BUILDS IN, PEAKING IN INTENSITY THURSDAY INTO FRIDAY.
HIGHS ARE FORECAST TO SOAR PAST 100 DEGREES FOR THE FIRST TIME THIS
SEASON (AND EARLIEST ON RECORD) FOR THE LOWER ELEVATIONS OF
SOUTHERN CALIFORNIA (AWAY FROM THE COAST) AND ARIZONA. NUMEROUS
DAILY RECORDS WILL BE BROKEN BY THE MIDDLE TO END OF THE WEEK, AND
MANY MONTHLY MARCH RECORDS ARE ALSO LIKELY. EXTREME HEAT WARNINGS
ARE ALREADY IN EFFECT TO ACCOUNT FOR THIS AND ALSO FOR HOW EARLY IN
THE SEASON THIS IS. WIDESPREAD WARMER THAN AVERAGE TEMPERATURES BY
20 TO 30 DEGREES WILL ALSO BE A CONCERN ACROSS MUCH OF THE
INTERMOUNTAIN WEST AND THE PLAINS INTO LATE WEEK, WITH TEMPERATURES
IN THE 80S INTO THE CENTRAL GREAT BASIN AND CENTRAL PLAINS, AND
90S IN THE SOUTHERN PLAINS. EXPECT TEMPERATURES TO STAY ABOVE
AVERAGE ACROSS THE WESTERN TO SOUTH-CENTRAL U.S. INTO EARLY NEXT
WEEK, BUT MODERATED COMPARED TO THIS WEEK.
ONE MORE COLD MORNING IS EXPECTED IN THE SOUTHEAST ON THURSDAY
UNDERNEATH A CHILLY SURFACE HIGH BEHIND A COLD FRONT, LEADING TO
POTENTIAL FROST/FREEZE CONCERNS IN AREAS WHERE VEGETATION COULD BE
SENSITIVE. THE SOUTHEAST SHOULD GRADUALLY WARM UP THROUGH THE REST
OF THE PERIOD TO ABOVE AVERAGE TEMPERATURES, BUT FARTHER NORTH
UPPER TROUGHING ATOP THE NORTHEASTERN U.S. WILL GRADUALLY LEAD TO
COOLER TEMPERATURES. THE EXACT TIMING OF THE TROUGH(S) AND RELATED
SURFACE LOW/FRONTAL SYSTEMS ARE UNCERTAIN, BUT A PATTERN OF RAIN
AND INLAND SNOW ARE POSSIBLE ACROSS THE GREAT LAKES AND MID-
ATLANTIC/NORTHEAST AT TIMES LATE THIS WEEK INTO EARLY NEXT WEEK.
IN TERMS OF EXCESSIVE RAINFALL, THE ONLY CONCERN WILL BE THE
PACIFIC NORTHWEST, WHERE THE SOUTHERN SIDE OF AN ATMOSPHERIC RIVER
WILL AFFECT WASHINGTON INTO THURSDAY AND THURSDAY NIGHT. CONTINUE
TO MAINTAIN A DAY 4 MARGINAL RISK FOR FLOODING CONCERNS ESPECIALLY
AFTER THE ALREADY WET PATTERN IN THE SHORT RANGE. THE AR SHOULD
LESSEN IN STRENGTH BY FRIDAY AND BEYOND, BUT SOME ADDITIONAL
PRECIPITATION IS POSSIBLE, REACHING THE NORTHERN ROCKIES AS WELL.
OTHER PARTS OF THE COUNTRY SHOULD REMAIN MOSTLY DRY.
TATE/HAMRICK
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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