334
FXUS02 KWBC 160701
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 AM EST THU NOV 16 2023
VALID 12Z SUN NOV 19 2023 - 12Z THU NOV 23 2023
..PATTERN OVERVIEW
A SPLIT FLOW PATTERN WILL PERSIST WELL INTO NEXT WEEK. SYSTEMS IN
A NORTHERN STREAM WILL TRACK EAST ACROSS CENTRAL/SOUTHERN CANADA
AND U.S. NORTHERN TIER WHILE SYSTEMS IN A SOUTHERN STREAM WILL
TRACK EAST ACROSS THE SOUTHERN UNITED STATES AND CURVE NORTHEAST
OVER THE EAST COAST. THIS WILL FUEL AN EMERGING WET PATTERN ACROSS
THIS BROAD AREA OF OUR FINE NATION NEXT WEEK.
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
MODEL AND ENSEMBLE SOLUTIONS REMAIN IN BETTER THAN AVERAGE
AGREEMENT THROUGH MEDIUM RANGE TIME SCALES AND OVERALL SEEM TO
PROVIDE A REASONABLE FORECAST BASIS. THE WPC PRODUCT SUITE WAS
PRIMARILY DERIVED FROM A COMPOSITE BLEND OF THE 18 UTC GFS AND 12
UTC ECMWF/UKMET/CANADIAN ALONG WITH THE 01 UTC NATIONAL BLEND OF
MODELS AND WPC CONTINUITY TO PROVIDE MAX DETAIL CONSISTENT WITH A
PATTERN WITH SEEMINGLY ABOVE NORMAL PREDICTABILITY FOR
SUNDAY-TUESDAY. NEWER 00 UTC GUIDANCE REMAINS REASONABLY WELL IN
LINE DURING THIS PERIOD. OPTED TO ADD MODEST INFLUENCE FROM THE 18
UTC GEFS MEAN AND 12 UTC ECMWF ENSEMBLE MEAN TO THE AFOREMENTIONED
COMPOSITE BLEND TO BEST MAINTAIN CONTINUITY INTO NEXT
WEDNESDAY/THURSDAY AMID SLOWLY GROWING FORECAST SPREAD AND RUN TO
RUN VARIANCES.
..WEATHER/HAZARDS HIGHLIGHTS
COLDER AIR WRAPPING AROUND THE BACKSIDE OF AN EXITING NORTHEAST
SYSTEM AND LEAD COASTAL LOW INTO SUNDAY WILL ALLOW FOR SOME
LINGERING WINTRY PRECIPITATION OVER NORTHERN NEW ENGLAND AND
DOWNSTREAM OF THE GREAT LAKES.
ELSEWHERE, HEAVY RAINFALL POTENTIAL WILL REMAIN LOW THROUGH THE
WEEKEND, BUT WILL INCREASE ACROSS THE SOUTH-CENTRAL TO EASTERN
U.S. NEXT WEEK AS A MAIN LOW PRESSURE SYSTEM DEEPENS AND TRACKS
ACROSS THE REGION. THE LOW WILL DEVELOP IN THE LEE OF THE ROCKIES
OVER THE CENTRAL/SOUTHERN PLAINS ON SUNDAY AND MOVE TO THE
EAST-CENTRAL STATES EARLY NEXT WEEK BEFORE CURVING TOWARDS THE
NORTHEAST MID-WEEK. THE TIGHTENING PRESSURE GRADIENT AS THE LOW
SPINS UP WILL LIKELY PRODUCE A PERIOD OF HIGH WINDS ACROSS THE
HIGH PLAINS EARLY NEXT WEEK. THERE IS NOW A SIGNAL FOR HEAVY
RAINFALL BY MONDAY WITH FOCUS OVER THE CENTRAL GULF COAST STATES
AND VICINITY, A WPC EXCESSIVE RAINFALL OUTLOOK "MARGINAL RISK AREA
WAS INTRODUCED TO ADDRESS THIS EMERGING THREAT. AMPLE MOISTURE
WILL STREAM INTO THE SOUTHERN AND EASTERN U.S. AHEAD OF THE SYSTEM
AS IT WORKS DOWNSTREAM, SO DESPITE PROGRESSION OVER TIME MAY LEAD
TO SOME LOCALIZED RUNOFF ISSUES IN THE VICINITY OF THE
CENTRAL/SOUTHERN APPALACHIANS ON TUESDAY AND THE MID-ATLANTIC AND
NORTHEAST ON WEDNESDAY. URBAN FLOODING POTENTIAL MAY BE A CONCERN
ESPECIALLY FOR THE METRO AREAS UP THROUGH MID-ATLANTIC AND THE
NORTHEAST. THERE IS SOME POSSIBILITY FOR SNOW ON THE NORTHERN
PERIPHERY OF THIS PRECIPITATION SHIELD.
IN THE WEST, UNSETTLED WEATHER INCLUDING A BURST OF MOUNTAIN SNOWS
IS EXPECTED SUNDAY AS NORTHERN STREAM UPPER TROUGH ENERGY DIGS
THROUGH THE NORTH-CENTRAL INTERMOUNTAIN WEST/ROCKIES. AN AMPLIFIED
UPPER RIDGE WILL THEN BUILD OVER THE WEST COAST EARLY NEXT WEEK,
RESULTING IN MORE STABLE AND DRY WEATHER. HOWEVER, UPSTREAM
PACIFIC SYSTEM ENERGIES MAY WORK INTO THIS RIDGE ENOUGH TO BRING
ANOTHER OPPORTUNITY FOR ORGANIZED PRECIPITATION INTO THE PACIFIC
NORTHWEST NEXT TUESDAY/WEDNESDAY.
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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