646
FXUS02 KWBC 160752
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
352 AM EDT MON MAR 16 2026
VALID 12Z THU MAR 19 2026 - 12Z MON MAR 23 2026
***IMPRESSIVE EARLY SEASON HEATWAVE CONTINUES ACROSS THE
SOUTHWESTERN U.S. THROUGH SATURDAY WITH NUMEROUS RECORDS***
..GENERAL OVERVIEW
AN AMPLIFIED UPPER LEVEL FLOW PATTERN WILL BE IN PLACE ACROSS THE
CONTINENTAL U.S. FOR THE MIDDLE TO END OF THE WEEK, AND GRADUALLY
BECOMING LESS AMPLIFIED BY NEXT SUNDAY/MONDAY. A HIGHLY ANOMALOUS
UPPER RIDGE SITUATED ACROSS THE DESERT SOUTHWEST WILL DELIVER
SUMMER-LIKE HEAT TO THIS REGION WITH RECORDS EXPECTED FOR MULTIPLE
DAYS, AND WIDESPREAD WELL ABOVE AVERAGE TEMPERATURES FOR MOST
AREAS WEST OF THE MISSISSIPPI RIVER. UPPER LEVEL TROUGHING SHOULD
PERSIST ACROSS THE EASTERN U.S. WITH A NEW LOW PRESSURE SYSTEM
LIKELY AFFECTING THE GREAT LAKES AND THE NORTHEAST BY THE WEEKEND
AND A MODEST ATMOSPHERIC RIVER ACROSS WASHINGTON STATE.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE 00Z MODEL GUIDANCE SUITE IS IN GOOD OVERALL AGREEMENT ON MOST
ASPECTS OF THE FORECAST THROUGH THE END OF THE WORK WEEK ACROSS
THE CONTINENTAL U.S., WITH A GENERAL DETERMINISTIC AND AIFS MODEL
GUIDANCE BLEND WORKING WELL AS A STARTING POINT FOR FRONTS AND
PRESSURES. WITH THE UPPER RIDGE BREAKING DOWN BY THE WEEKEND, THERE
ARE STILL NOTEWORTHY DIFFERENCES IN NORTHERN STREAM ENERGY THAT
WILL EVENTUALLY SUPPORT SURFACE LOW DEVELOPMENT OVER THE GREAT
LAKES AND NORTHEAST BY SUNDAY, WITH THE GFS/CMC STRONGER AND THE
ECMWF WEAKER. THE GFS IS QUICKER TO BREAK DOWN THE WESTERN U.S.
RIDGE, WHEREAS THE CMC/ECMWF ARE MORE INDICATIVE OF ZONAL FLOW HERE
BY NEXT MONDAY. THE ENSEMBLE MEANS WERE INCREASED TO ABOUT 40% BY
NEXT MONDAY GIVEN MORE MODEL SPREAD IN SYSTEM TIMING. THE NBM
LOOKED REASONABLE FOR THE MOST PART, BUT WINDS WERE RAISED ACROSS
MUCH OF THE WEST TO BETTER ACCOUNT FOR THE INCOMING COLD FRONT AND
INCREASED PRESSURE GRADIENT.
..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 WATCHES
ARE ALREADY IN EFFECT TO ACCOUNT FOR THIS AND ALSO FOR HOW EARLY IN
THE SEASON THIS IS. WIDESPREAD WARMER THAN AVERAGE TEMPERATURES
WILL ALSO BE A CONCERN ACROSS MUCH OF THE INTERMOUNTAIN WEST AND
EXPANDING EAST TO THE WESTERN HIGH PLAINS FOR THE SECOND HALF OF
THE WEEK, WITH HIGHS LIKELY TO BE WELL INTO THE 90S ACROSS WESTERN
TEXAS AND MUCH OF NEW MEXICO. READINGS OVERALL ARE LIKELY TO BE
20-30 DEGREES ABOVE MID-MARCH LEVELS FROM THE SOUTHWEST UP TO THE
WESTERN DAKOTAS.
COLDER WEATHER WILL BE IN PLACE ACROSS THE EAST COAST REGION FOR
THE MIDDLE OF THE WEEK WITH A CANADIAN SURFACE HIGH IN PLACE, BUT
THERE SHOULD BE A GRADUAL MODERATION IN TEMPERATURES TOWARDS THE
END OF THE WEEK AS THE SURFACE HIGH MOVES OFFSHORE. RAIN AND INLAND
SNOW ACROSS THE NORTHERN MID-ATLANTIC AND THE NORTHEAST COULD MAKE
A RETURN IN TIME FOR NEXT WEEKEND AS THE NEXT STORM SYSTEM
APPROACHES FROM THE GREAT LAKES, ALTHOUGH UNCERTAINTIES REMAIN.
IN TERMS OF EXCESSIVE RAINFALL, THE MARGINAL RISK AREA ACROSS THE
OLYMPIC PENINSULA AND THE WESTERN SLOPES OF THE CASCADES WILL
REMAIN VALID FOR THE DAY 4/THURSDAY TIME PERIOD, WITH A MODERATELY
STRONG ATMOSPHERIC RIVER DRIFTING SOUTH FROM BRITISH COLUMBIA.
THERE WILL BE SOME ABATEMENT IN THE PRECIPITATION GOING INTO DAY
5/FRIDAY, SO NO RISK AREAS ARE NECESSARY. ELSEWHERE ACROSS THE
CONTINENTAL U.S., A MAINLY DRY WEATHER PATTERN CAN BE EXPECTED.
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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