744
FXUS02 KWBC 231902
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 PM EST FRI FEB 23 2024
VALID 12Z MON FEB 26 2024 - 12Z FRI MAR 01 2024
..OVERVIEW
AN UPPER RIDGE TRAVERSING THE CENTRAL AND EASTERN U.S. FOR THE
FIRST HALF OF NEXT WEEK WILL SPREAD MUCH ABOVE NORMAL TEMPERATURES
TO THE PLAINS AND MIDWEST AND THEN THE EAST. MEANWHILE, NORTHERN
AND WEAKER SOUTHERN-STREAM TROUGHING FROM THE PACIFIC LOOK TO
TRACK INTO THE WEST AND BRING COOLER TEMPERATURES,
ELEVATION-DEPENDENT RAIN/SNOW, AND WINDY CONDITIONS FROM THE WEST
COAST TO THE ROCKIES THROUGH EARLY NEXT WEEK. DOWNSTREAM
TRANSLATION MAY THEN SUPPORT EMERGING GENESIS OF SYSTEMS AND
PRECIPITATION PATTERN FROM THE SOUTH-CENTRAL U.S. TO THE
MIDWEST/GREAT LAKES ONWARD INTO MIDWEEK, ALONG WITH A
POST-FRONTAL/TRAILING SOUTHWARD SURGE OF A COLD CANADIAN HIGH
PRESSURE SYSTEM TO OFFER SOME WINTRY POTENTIAL FOR THE
NORTHEASTERN QUARTER OF THE COUNTRY MID TO LATE NEXT WEEK BUT WITH
TIMING UNCERTAINTY.
..GUIDANCE/PREDICTABILITY ASSESSMENT
AS THE FORECAST PERIOD BEGINS NEXT MONDAY, GUIDANCE REMAINS IN
REASONABLY GOOD AGREEMENT DEPICTING AN UPPER-LEVEL TROUGH DIVING
SOUTHEAST ALONG THE WEST COAST OF CANADA TOWARDS THE PACIFIC
NORTHWEST. THE MAIN FORECAST CHALLENGE REMAINS WITH HOW THIS
NORTHERN STREAM TROUGH WILL LATER INTERACT WITH A DE-AMPLIFIED
UPPER-LOW LIFTING NORTHEAST FROM OFF THE COAST OF CALIFORNIA BY
THE TIME THEY REACH THE MID-SECTION OF THE COUNTRY ABOUT NEXT
TUESDAY. IT APPEARS THAT THE GENERAL EASTWARD ACCELERATION OF THE
GUIDANCE CONSENSUS FOR THIS SYSTEM HAS CONTINUED THIS MORNING,
PUSHING WHAT APPEARS TO BE A WELL-DEFINED COLD FRONT FASTER INTO
THE EASTERN U.S. BY NEXT WEDNESDAY. THE EC ENSEMBLE MEANS APPEAR
TO HAVE PERFORMED THE BEST SO FAR WITH THIS SYSTEM. GUIDANCE
UNCERTAINTY APPEARS TO IMPROVE ACROSS THE U.S. LATE NEXT WEEK AS
THE UNCERTAIN UPPER TROUGH LIFTS OFF THE NORTHEAST AND A RIDGE
PROGRESSIVELY BUILDS FROM THE SOUTHWEST INTO THE MID-SECTION OF
THE COUNTRY.
THE WPC MEDIUM-RANGE FORECAST PACKAGE WAS BASED ON A CONSENSUS OF
THE 06Z GFS/GEFS, 00Z EC/EC MEAN, AND SOME CONTRIBUTIONS FROM THE
00Z CMC/CMC MEAN. THIS BLEND PROVIDED QPF AND MASS FIELDS THAT
WERE VERY COMPATIBLE TO WPC CONTINUITY FROM 12 HOURS AGO, ALTHOUGH
A SOUTHWARD SHIFT ON THE QPF AXIS OVER THE MIDWEST, DUE TO THE
FASTER EASTWARD PROGRESSION OF THE LOW/FRONT MIDWEEK, WAS NOTED
BASED ON THE LATEST GUIDANCE CONSENSUS.
..WEATHER/HAZARDS HIGHLIGHTS
AS TROUGHING COMES INTO THE WEST EARLY NEXT WEEK, PRECIPITATION
WILL SPREAD INTO THE PACIFIC NORTHWEST AND NORTHERN ROCKIES INTO
MONDAY, INCLUDING SNOW THAT COULD BE HEAVY OVER FAVORED TERRAIN.
PRECIPITATION MAY NOW SPREAD THROUGH CALIFORNIA AND INTO THE
INTERMOUNTAIN WEST BY MONDAY, THEN OUT THROUGH THE ROCKIES TUESDAY
GIVEN LESS LIKELY STREAM PHASING AND NORTHERN STREAM UPPER TROUGH
PROGRESSION. ADDITIONAL MOISTURE AHEAD OF ADDITIONAL SYSTEMS
UPSTREAM OVER THE PACIFIC WILL CONTINUE PRECIPITATION CHANCES IN
THE PACIFIC NORTHWEST THEN CALIFORNIA THROUGH WEDNESDAY-NEXT
FRIDAY. OVERALL, THE HIGHEST LIKELIHOOD FOR WINTER-RELATED IMPACTS
IS IN THE CASCADES, SIERRA, AND PORTIONS OF THE NORTHERN/CENTRAL
ROCKIES, THOUGH MOST OF THE REGIONAL HIGHER ELEVATION MOUNTAIN
RANGES WILL AT LEAST SEE SOME SNOW THROUGH THE PERIOD. WIDESPREAD
STRONG, GUSTY WINDS ARE ALSO EXPECTED ACROSS MUCH OF THE WEST,
PARTICULARLY FOR HIGHER ELEVATIONS, AS A COUPLE FRONTAL SYSTEMS
PASS THROUGH, LINGERING THE LONGEST ALONG THE EASTERN
RANGES/FOOTHILLS OF THE ROCKIES AND IMMEDIATE HIGH PLAINS.
PRECIPITATION CHANCES WILL BEGIN TO INCREASE TUESDAY INTO
WEDNESDAY ACROSS MUCH OF THE EASTERN HALF TO THIRD OF THE COUNTRY
AS MOIST SOUTHERLY FLOW INCREASES AHEAD OF THE APPROACHING
UPPER-LEVEL TROUGH AND SURFACE LOW PRESSURE/FRONTAL SYSTEM FROM
THE WEST. MOST PRECIPITATION WILL BE IN THE FORM OF RAIN GIVEN
ANOMALOUS LEAD WARMTH, BUT SOME SNOW ON THE BACKSIDE OF THE LOW
AND COLD FRONT FOR THE UPPER MIDWEST/GREAT LAKES. THE WPC WINTER
WEATHER OUTLOOK HAS INCREASED PROBABILITIES THERE GIVEN THE LOW
AND POST-FRONTAL COLD ONSET. SOME RAINFALL AMOUNTS COULD BE
MODERATELY HEAVY, PARTICULARLY FOR THE OHIO VALLEY, WITH MULTIPLE
ROUNDS OF RAIN POSSIBLE THROUGH AT LEAST MIDWEEK. IN ADDITION, THE
MOIST, UNSTABLE AIRMASS AS WELL AS INCREASINGLY STRONG WINDS ALOFT
WITH THE APPROACHING TROUGH WILL BRING THE CHANCE FOR SOME SEVERE
THUNDERSTORMS, WITH THE STORM PREDICTION CENTER HIGHLIGHTING THIS
THREAT FROM THE SOUTHERN PLAINS TO MIDDLE MISSISSIPPI VALLEY
TUESDAY AND INTO THE MID-SOUTH AND OHIO/TENNESSEE VALLEYS
WEDNESDAY, WITH ADDITIONAL SOUTHWARD SHIFT OF THE QPF AXIS AS
NOTED ABOVE. LATER WEEK PRECIPITATION FOCUS ACROSS THE SOUTH
APPEARS BETTER DEFINED THIS FORECAST CYCLE AS THE PRECIPITATION
GENERALLY PUSHES EAST TOWARD THE SOUTHEASTERN U.S. BY NEXT FRIDAY.
THE CENTRAL U.S. WILL SEE QUITE MILD TO WARM TEMPERATURES EARLY
NEXT WEEK UNDERNEATH AN UPPER RIDGE. TEMPERATURES OF 20-35 DEGREES
ABOVE AVERAGE WILL EXPAND THROUGHOUT THE PLAINS AND MISSISSIPPI
VALLEY, PUTTING ACTUAL TEMPERATURES INTO THE 80S AND EVEN 90S IN
TEXAS BY MONDAY-TUESDAY WHILE 60S REACH AS FAR NORTH AS SOUTH
DAKOTA AND IOWA, WITH POTENTIAL FOR WIDESPREAD RECORDS. THE UPPER
TROUGH AND COLD FRONT PRESSING EASTWARD SHOULD COOL TEMPERATURES
DOWN CLOSER TO NORMAL OR A FEW DEGREES BELOW IN THE CENTRAL U.S.
BY MIDWEEK, BUT TEMPERATURES COULD ALREADY START TO REBOUND BY
THURSDAY. THE WELL ABOVE NORMAL TO POSSIBLY RECORD-BREAKING
TEMPERATURES WILL GET SHUNTED EASTWARD AHEAD OF THE UPPER
TROUGH/UNDERNEATH THE UPPER RIDGE INTO THE EAST-CENTRAL AND THEN
EASTERN U.S. TUESDAY-THURSDAY. 70S SHOULD BE WIDESPREAD ACROSS THE
SOUTHEAST AND COULD EVEN REACH AS FAR NORTH AS THE MID-ATLANTIC.
MEANWHILE THE WEST IS FORECAST TO SEE NEAR TO SLIGHTLY ABOVE
NORMAL TEMPERATURES INTO SUNDAY, BUT COOLING TO BELOW NORMAL
PARTICULARLY IN TERMS OF HIGHS BY MONDAY-TUESDAY AS UPPER
TROUGHING COMES IN.
KONG/SCHICHTEL
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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