784
FXUS02 KWBC 130752
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
352 AM EDT THU OCT 13 2022
VALID 12Z SUN OCT 16 2022 - 12Z THU OCT 20 2022
..PATTERN OVERVIEW
AN AMPLIFIED UPPER-LEVEL PATTERN, WITH A RIDGE IN THE WEST AND A
TROUGH IN THE EAST WILL SUPPORT AUTUMN-LIKE TEMPERATURES ACROSS
THE CONUS. A POTENT UPPER LOW WILL WEAKEN AS IT MOVES INTO THE
SOUTHWEST FROM THE BAJA PENINSULA EARLY NEXT WEEK. THIS WEAKENED
UPPER LOW MAY PRODUCE HEAVY RAINFALL OVER PARTS OF THE SOUTHWEST
AND TEXAS GULF COAST THROUGH MONDAY. DEEP TROUGHING IN THE EAST
WILL PRODUCE RAIN SHOWERS AND COOL TEMPERATURES THROUGH TUESDAY.
SOME LIGHT LAKE EFFECT SNOW IS POSSIBLE OVER THE GREAT LAKES. WELL
BELOW AVERAGE TEMPERATURES ARE LIKELY OVER MUCH OF THE EAST ON THE
BACKSIDE OF THE DEEP TROUGH.
..MODEL AND PREDICTABILITY ASSESSMENT
GUIDANCE WAS IN REASONABLE AGREEMENT REGARDING THE EVOLUTION OF
THE SYNOPTIC SCALE PATTERN ACROSS THE LOWER 48 DURING THE MEDIUM
RANGE PERIOD. A GENERAL MODEL BLEND OF PREDOMINANTLY DETERMINISTIC
GUIDANCE CONSISTING OF THE 12Z EC/UK/CMC AND 18Z GFS WERE USED
THROUGH DAY 5 BEFORE INCORPORATING A MAJORITY ENSEMBLE MEAN BLEND
CONSISTING OF THE 12Z ECE/CMC AND 18Z GEFS. QPF TRENDS SUGGEST A
MORE PROGRESSIVE SOLUTION WITH RESPECT TO THE HEAVIEST AXIS OF
RAINFALL IN THE SOUTHERN PLAINS/SOUTHWEST EARLY NEXT WEEK. THE
LAST SEVERAL RUNS OF THE GFS AND EC SEESAWED 24 HOUR QPF MAXIMA
ALONG THE CENTRAL TEXAS COAST NEXT MONDAY. THE GFS IS A BIT FASTER
THAN THE EC WITH THE AXIS OF RAINFALL ALONG THE NORTHEAST COAST
EARLY NEXT WEEK. SOME UNCERTAINTY EXISTS WITH RESPECT TO THE
WEAKENING UPPER LOW OVER THE SOUTHWEST. THIS WILL INFLUENCE RAIN
HAZARDS IN THE SOUTHERN PLAINS/TEXAS NEXT WEEK.
..SENSIBLE WEATHER AND POTENTIAL HAZARDS
HEAVY RAINFALL IS LIKELY TO DEVELOP ALONG A SURFACE BOUNDARY OVER
THE SOUTHWEST AND SOUTHERN PLAINS SUNDAY AND THEN FOCUS OVER
CENTRAL/COASTAL TEXAS ON MONDAY. A POTENT CUT-OFF LOW, EMBEDDED
WITHIN AN AMPLIFIED UPPER RIDGE, WILL WEAKEN AS IT MOVES INTO THE
SOUTHWEST, BUT THE EXTENT TO WHICH IT WEAKENS WILL DETERMINE THE
AMOUNT OF RAINFALL THAT PARTS OF EASTERN ARIZONA, NEW MEXICO AND
SOUTHERN/CENTRAL/COASTAL TEXAS GET ON SUNDAY AND MONDAY. FOR NOW,
A SLIGHT RISK OF EXCESSIVE RAINFALL IS IN EFFECT OVER PORTIONS OF
EASTERN-CENTRAL ARIZONA INTO THE BIG BEND OF TEXAS ON SUNDAY.
PARTS OF SOUTHEASTERN NEW MEXICO ARE EMBEDDED WITHIN THE SLIGHT
AREA, BUT DRY SOILS AND A LACK OF ANTECEDENT PRECIPITATION MAY
MAKE FLASH FLOODING MORE OF A MARGINAL RISK. BY MONDAY THE FLASH
FLOOD THREAT SHIFTS INTO COASTAL TEXAS WHERE AN UPGRADE TO A
SLIGHT RISK CAN'T BE RULED OUT IF MODELS TREND A BIT HIGHER WITH
QPF TO OVERCOME DRY SOILS IN THE COMING DAYS.
MEANWHILE, SHORTWAVES ROTATING AROUND A MEAN UPPER-LEVEL TROUGH
WILL DEVELOP A POTENT SURFACE WAVE THAT WILL GENERATE MODERATE TO
HEAVY RAINFALL OVER THE GREAT LAKES AND NORTHEAST ON MONDAY AND
TUESDAY. WELL BELOW AVERAGE TEMPERATURES AND LIGHT LAKE EFFECT
SNOW ARE POSSIBLE ON THE BACKSIDE OF THIS SYSTEM AS IT PUSHES INTO
EASTERN CANADA. HIGH PRESSURE BUILDS OVER THE MIDWEST AND
SOUTHEAST IN THE WAKE OF A COLD FRONT, WHICH WILL ALL FOR THE FLOW
OF COOL NORTHERLY AIR TO SETTLE OVER THE REGION. THINGS QUIET DOWN
A BIT BY MIDWEEK.
THE WEST WILL EXPERIENCE ABOVE AVERAGE TEMPERATURES DUE TO THE
PRESENCE OF AN AMPLIFIED RIDGE NEXT WEEK. PARTS OF THE NORTHWEST
WILL BE PARTICULARLY WARMER THAN NORMAL WITH HIGHS BETWEEN 10-20
DEGREES ABOVE AVERAGE.
KEBEDE
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, EXPERIMENTAL EXCESSIVE RAINFALL
OUTLOOK, WINTER WEATHER OUTLOOK PROBABILITIES AND HEAT INDICES 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
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