754
FXUS02 KWBC 080656
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
255 AM EDT SAT OCT 8 2022
VALID 12Z TUE OCT 11 2022 - 12Z SAT OCT 15 2022
..GENERAL PATTERN OVERVIEW
AN ANOMALOUS MID-UPPER RIDGE AXIS ACROSS THE EASTERN PACIFIC IS
EXPECTED TO BE NEARLY ANCHORED IN PLACE FOR MUCH OF NEXT WEEK, AND
THIS WILL TEND TO RESULT IN AN AMPLIFYING DOWNSTREAM TROUGH OVER
CENTRAL CANADA AND INTO THE NORTH-CENTRAL U.S. GOING INTO THE
MIDDLE OF THE WEEK, AND THIS WILL BE ACCOMPANIED BY ANOTHER STRONG
COLD FRONT EAST OF THE ROCKIES. THIS WILL HELP REINFORCE THE
AUTUMNAL AIRMASS ACROSS MUCH OF THE EASTERN U.S., WHILE STILL
REMAINING MILD TO WARM ACROSS THE NORTHWESTERN U.S. AND THE
SOUTHERN TIER STATES.
..MODEL AND PREDICTABILITY ASSESSMENT
IN TERMS OF THE BUILDING NORTHERN STREAM UPPER TROUGH FOR THE
MIDDLE OF NEXT WEEK, THE MODELS CONTINUE TO AGREE ON A STRONGLY
AMPLIFYING TROUGH IN THE NORTHERN STREAM FLOW WITH LESS SIGNAL FOR
A CUT-OFF LOW BREAKING AWAY ACROSS THE WESTERN U.S., AND THE CMC
IS STARTING TO SLOWLY TREND TOWARDS THE MODEL/ENSEMBLE CONSENSUS
IN DEPICTING LESS OF A WESTERN U.S. UPPER LOW. TELECONNECTIONS
WITH THE POSITIVE HEIGHT ANOMALY OVER THE EASTERN PACIFIC AND THE
NEGATIVE HEIGHT ANOMALY NORTH OF HAWAII SUGGEST A NON-CMC
SOLUTION, AND THIS WOULD NOT SUPPORT A WELL-DEFINED UPPER LOW
BREAKING OFF FROM THE MAIN TROUGH.
SIMILAR TO YESTERDAY, THE FORECAST WAS PRIMARILY DERIVED FROM A
UKMET/GFS/ECMWF/WPC CONTINUITY COMPOSITE THROUGH WEDNESDAY, AND
THEN SOME OF THE GFS AND PAST TWO RUNS OF ECMWF AND INCREASED USE
OF THE ENSEMBLE MEANS FOR THE THURSDAY THROUGH SATURDAY TIME
PERIOD.
..SENSIBLE WEATHER AND POTENTIAL HAZARDS
AN AMPLIFYING UPPER TROUGH AND A STRONG COLD FRONT REACHING THE
NORTHERN PLAINS AND UPPER MIDWEST BY EARLY WEDNESDAY WILL LIKELY
PRODUCE SHOWERS AND SOME THUNDERSTORMS FROM THE CENTRAL PLAINS TO
THE GREAT LAKES, ALTHOUGH RAINFALL TOTALS SHOULD BE LIGHT TO
MODERATE. THERE WILL LIKELY BE AN UPTICK IN SHOWERS AND
THUNDERSTORM COVERAGE AS THE FRONT APPROACHES THE OHIO VALLEY AND
THEN NORTHEAST U.S. TOWARDS THE END OF THE WEEK, AND ALSO FOR THE
GULF COAST REGION AS THE FRONT TAPS INTO DEEPER MOISTURE. THE
LATEST NBM HAS SOME AREAL 2-4 INCH RAINFALL TOTALS FROM UPSTATE
NEW YORK TO MAINE FOR THE THURSDAY TO FRIDAY NIGHT TIME PERIOD AS
DEEPER ATLANTIC MOISTURE IS ADVECTED TOWARDS THE NORTHERN
APPALACHIANS. ELSEWHERE, THE MONSOONAL CONVECTION ACROSS THE
SOUTHERN ROCKIES AND ARIZONA IS FINALLY EXPECTED TO SUBSIDE GOING
INTO THE MIDDLE OF THE WEEK AS THE UPPER LOW/TROUGH WEAKENS,
ALTHOUGH SOME ISOLATED STORMS MIGHT REMAIN THROUGH WEDNESDAY.
SOME HIGH ELEVATION SNOW SHOWERS ARE ALSO POSSIBLE FOR THE HIGHEST
TERRAIN OF THE CENTRAL AND NORTHERN ROCKIES ON TUESDAY AND
WEDNESDAY.
MUCH OF THE NORTHWESTERN U.S. SHOULD HAVE ABOVE NORMAL
TEMPERATURES NEXT WEEK WITH THE UPPER RIDGE JUST OFF THE COAST,
AND A WARM-UP IS LIKELY ACROSS THE CENTRAL/NORTHERN PLAINS
TUESDAY/WEDNESDAY AHEAD OF THE FRONT. THIS WILL LIKELY BE
FOLLOWED BY HIGHS ABOUT 5-15 DEGREES BELOW AVERAGE TO CLOSE OUT
THE WORK WEEK FROM THE UPPER MIDWEST TO THE OHIO VALLEY AND GREAT
LAKES, AND POTENTIAL FOR SOME FROST/FREEZE CONDITIONS AT NIGHT,
MAINLY NORTH OF THE OHIO RIVER.
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, 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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